Healthcare Associated Outbreak Management Manual

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Kingdom of Saudi Arabia
Ministry of Health
General Directorate of Infection Prevention and Control
الجراحه الصحيه
Ministry of Health
Healthcare-Associated
Outbreak Management Manual
September 2023
V. 7.1
Contributors
Written by:
Members of the GDIPC- MOH Outbreak team
Mrs. Eman Barnawi
Dr. Hala Roushdy
Dr. Nadeen Burhan
Dr. Nasser Alsharif
Mr. Nawaf Almatrafi
Mrs. Nawal Alenazi
Mrs. Safaa Fallatah
Mr. Yahya Alnshbah
Ms. Zainah Alshahrani
Edited by:
Dr. Aiman El-Saed Ramadan
Approved by:
Dr. Khalid H. Alanazi
General director of infection Prevention and Control, GDIPC, MOH
® 2023 Ministry of Health, Riyadh, Saudi Arabia

Message of the General Director
This manual (January 2023 edition) of the “Healthcare-Associated Outbreak Management Manual”, was prepared by the General Directorate of Infection Prevention and Control (GDIPC) Outbreak Management Department. The current edition aimed at guiding healthcare workers, especially infection preventionists who manage healthcare-associated infections (HAIs) across different levels of Healthcare Facilities in Saudi Arabia. The 7th version included several modifications based on the feedback of fellow professionals.
This manual helps in early detection and notification, proper investigation, management, and control of outbreaks. It is considered an essential strategy for managing healthcare-associated outbreaks in the Ministry of Health and non-Ministry of Health Hospitals.
I encourage healthcare workers to follow and implement this manual with great care, as it is expected to have a beneficial effect in reducing the number of outbreaks and their associated morbidity and mortality.
My sincere thanks to members of the Outbreak Management Department for their contributions and hard efforts in formulating, editing, reviewing, submitting, and publishing this manual.
Dr. Khalid H. Alanazi
General director of infection Prevention and Control, GDIPC, MOH

Abbreviations
<table><tr><td>AIDS</td><td>Acquired Immunodeficiency Syndrome</td></tr><tr><td>ARDS</td><td>Acute respiratory distress syndrome</td></tr><tr><td>ASC</td><td>Active surveillance cultures</td></tr><tr><td>ATP</td><td>Adenosine Triphosphate</td></tr><tr><td>BAL</td><td>Bronchoalveolar Lavage</td></tr><tr><td>C. Diff</td><td>Clostridium Difficile</td></tr><tr><td>CAP</td><td>Community Acquired Pneumonia</td></tr><tr><td>CAUTI</td><td>Catheter-Associated Urinary Tract Infection</td></tr><tr><td>CDC</td><td>Centers For Disease Control and Prevention</td></tr><tr><td>CDI</td><td>Clostridium difficile infections</td></tr><tr><td>CHG</td><td>Chlorhexidine gluconate</td></tr><tr><td>CLABSI</td><td>Central Line Associated Bloodstream Infection</td></tr><tr><td>CO</td><td>Community-onset</td></tr><tr><td>COVID-19</td><td>Coronavirus Disease 2019</td></tr><tr><td>CRE</td><td>Carbapenem-Resistant Enterobacteriaceae</td></tr><tr><td>CRKP</td><td>Carbapenem-resistant Klebsiella pneumonia</td></tr><tr><td>CSF</td><td>Cerebrospinal Fluid</td></tr><tr><td>DNA</td><td>Deoxyribonucleic Acid</td></tr><tr><td>ELISA</td><td>Enzyme-Linked Immunoassay</td></tr><tr><td>ESBL</td><td>Extended-Spectrum Beta-Lactamases</td></tr><tr><td>FFP2</td><td>Filtering Face Pieces Offer Protection</td></tr><tr><td>GDIPC</td><td>General Directorate for Infection Prevention &amp; Control</td></tr><tr><td>GIT</td><td>Gastrointestinal tract</td></tr><tr><td>HAI</td><td>Healthcare-Associated Infections</td></tr><tr><td>HAIO</td><td>Hospital-Associated Infection Outbreaks</td></tr><tr><td>HAP</td><td>Hospital Acquired Pneumonia</td></tr><tr><td>HBsAg</td><td>Hepatitis B Surface Antigen</td></tr><tr><td>HCW</td><td>Health care workers</td></tr><tr><td>HEPA</td><td>High-Efficiency Particulate Air</td></tr><tr><td>HAV</td><td>Hepatitis A Virus</td></tr><tr><td>HBV</td><td>Hepatitis B Virus</td></tr><tr><td>HCV</td><td>Hepatitis C Virus</td></tr><tr><td>HIV</td><td>Human Immunodeficiency Virus</td></tr><tr><td>HO</td><td>Healthcare facility-onset</td></tr><tr><td>HSCT</td><td>Hematopoietic stem cell transplantation</td></tr><tr><td>HVAC</td><td>Heating, Ventilation, and Air Conditioning.</td></tr><tr><td>IC</td><td>Infection Control</td></tr><tr><td>ICP</td><td>Infection Control Practitioner</td></tr></table>
III

<table><tr><td>ICU</td><td>Intensive Care Unit</td></tr><tr><td>ILI</td><td>Influenza Like Illness</td></tr><tr><td>IP</td><td>Infection Preventionist</td></tr><tr><td>IPC</td><td>Infection Prevention and Control</td></tr><tr><td>IT</td><td>Information Technology</td></tr><tr><td>IV</td><td>Intravenous</td></tr><tr><td>LCM</td><td>Lymphocytic choriomeningitis</td></tr><tr><td>MDR</td><td>Multidrug-Resistant</td></tr><tr><td>MDRO</td><td>Multidrug-Resistant Organisms</td></tr><tr><td>MDR-TB</td><td>Multidrug-Resistant Tuberculosis</td></tr><tr><td>MERS-CoV</td><td>Middle East Respiratory Syndrome Coronavirus</td></tr><tr><td>MMR</td><td>Measles, Mumps, and Rubella</td></tr><tr><td>MOH</td><td>Ministry of Health</td></tr><tr><td>MRSA</td><td>Methicillin-Resistant Staphylococcus Aureus</td></tr><tr><td>MSSA</td><td>Methicillin-Sensitive Staphylococcus Aureus</td></tr><tr><td>NIAID</td><td>National Institute of Allergy and Infectious Diseases</td></tr><tr><td>N95</td><td>Non-Oil 95 Percent Efficiency Mask</td></tr><tr><td>OMAP</td><td>Outbreak Management Action Plan</td></tr><tr><td>OMT</td><td>Outbreak Management Team</td></tr><tr><td>OR</td><td>Operating Room</td></tr><tr><td>PCR</td><td>Polymerase Chain Reaction</td></tr><tr><td>PDR</td><td>Pan-Drug Resistance</td></tr><tr><td>PFGE</td><td>Pulsed-field gel electrophoresis</td></tr><tr><td>PPE</td><td>Personal Protective Equipment</td></tr><tr><td>RHD</td><td>Regional Health Directorate</td></tr><tr><td>RNA</td><td>Ribonucleic Acid</td></tr><tr><td>RSV</td><td>Respiratory Syncytial Virus</td></tr><tr><td>SARI</td><td>Acute Respiratory Infection</td></tr><tr><td>SARS</td><td>Severe Acute Respiratory Syndrome</td></tr><tr><td>SOT</td><td>Solid organ transplantation</td></tr><tr><td>SSI</td><td>Surgical Site Infection</td></tr><tr><td>TB</td><td>Tuberculosis</td></tr><tr><td>UTI</td><td>Urinary Tract Infection</td></tr><tr><td>VAP</td><td>Ventilator-Associated Pneumonia</td></tr><tr><td>VRE</td><td>Vancomycin-Resistant Enterococci</td></tr><tr><td>VZV</td><td>Varicella Zoster Virus</td></tr><tr><td>WGS</td><td>Whole genome sequencing</td></tr><tr><td>XDR</td><td>Extensive Drug Resistance</td></tr><tr><td>WHO</td><td>World Health Organization</td></tr></table>
IV

Table of Contents
Contributors.... I
Message of the General Director.... II
Abbreviations .... III
Introduction to epidemiology of infectious diseases....1
Steps of investigation of an outbreak ....18
Steps of the initial investigation of an outbreak....19
Steps of follow-up investigation of an outbreak .... 31
Post-outbreak analytic studies .... 33
Use of Epidemic Curve in outbreak ....35
Epidemiology and Prevention of MDRO outbreaks....39
Epidemiology of specific MDRO outbreaks in hospitals....51
MRSA....52
VRE 55
CRE 57
ESBL 60
MDR Pseudomonas aeruginosa....62
MDR Acinetobacter 64
Clostridium difficile 66
Epidemiology of specific bacterial outbreaks in hospitals ....69
Tuberculosis (TB)....70
Legionella....72
Burkholderia 74
Epidemiology of specific viral outbreaks in hospitals....76
SARS 77
SARS-cov-2 (COVID-19)....79
MERS-CoV 83
Influenza Viruses A and B 85
Varicella....87
Measles....89
Respiratory Syncytial Virus....91
Hepatitis B virus....92
Hepatitis C virus 94
V

Hepatitis A Virus....96
Rotavirus....98
Epidemiology of specific fungal outbreaks in hospitals ....99
Nosocomial/invasive candidiasis 100
Candida Auris 102
Aspergillosis....106
Operation of Outbreak 108
Outbreak Classification Matrix- Class A....110
Outbreak Classification Matrix- Class B....113
Outbreak Classification Matrix- Class C....116
References 119
Appendices 121
Appendix-1: Incubation periods....122
Appendix-2: Emerging Infectious Diseases 123
Appendix-3: Survival of Microorganisms....125
Appendix-4: Control measures....129
Appendix-5: Environmental Sampling 130
Appendix-6: Intensified interventions to prevent MDROs 135
Appendix-7: Risk Assessment Tool for MDRO 141
Appendix-8: MRSA Decolonization 143
Appendix-9 Classification of organisms....145
VI

Introduction to epidemiology of infectious diseases
Natural course of disease:
It refers to the progression of a disease process in an individual over time in the absence of treatment

Impacts of pathogens:
<table><tr><td>Infection</td><td>Colonization</td></tr><tr><td>Infection is the entry and multiplication of organisms in the tissue of a host.Infection may be clinical or subclinical and may not produce identifiable disease.However, it is usually accompanied by measurable host response(s), either through the appearance of specific antibodies or through cell-mediated reaction(s)</td><td>The multiplication of a microorganism at a body site or sites without any overt clinical expression or detected immune reaction in the host at the time that the organism is isolated.Colonization may or may not be a precursor of infection.Colonization may be a form of carriage and a potential transmission source.Commensal or normal flora are microorganisms present in or on a body site without causing clinical infection.</td></tr></table>

Types of patients:
<table><tr><td>Case</td><td>Carrier</td></tr><tr><td>A case is a person who has the pathogen multiplying (infected) and meets the case definition of a specific diseaseA clinical case is a term that refers to overt disease when the signs and symptoms are apparentThe subclinical case is a term that refers to an apparent (subclinical) infection, and an immune response can occur without overt clinical disease.</td><td>A carrier is a person in whom organisms are present and may be multiplying but who shows no clinical response to their presence.The carrier state may be permanent, with the organism always present; intermittent, with the organism present for various periods; or temporary, with carriage for only a brief period.Carriers may shed microorganisms during the incubation period and recovery.</td></tr></table>
Timelines for infection and disease
<table><tr><td>Infection-wise</td><td>Disease-wise</td></tr><tr><td>Latent period (also known as the latency period or the pre-infectious period): It is the time interval from exposure to infection (infected by a pathogen) to infectiousness (capable of transmitting pathogens to other susceptible individuals).It is usually shorter or sometimes similar to the incubation period</td><td>Incubation period: It is the time from exposure to infection (infected by a pathogen) to the development of symptomatic disease (appearance of the first symptom)It is usually longer or sometimes similar to the latent period.It determines the duration of quarantine for exposed persons until they can resume regular activities.</td></tr><tr><td>Infectious period (also known as the period of communicability or infectivity): It is the time during which the host is infectious (capable of transmitting pathogens to other susceptible individuals)A related term is a shedding period, which is defined as the period during which a host or patient excretes pathogens through sputum, saliva, urine, feces, or other bodily fluids.</td><td>Symptomatic period: It is the period in which characteristic symptoms of the disease are presentAlthough variable form disease to disease, the patient can be infectious before and after the symptomatic period</td></tr></table>
For incubation periods of common infectious diseases, see Appendix-1: Incubation periods

Exercise: A child was exposed to a case of chickenpox on Jan 6 and got a fever and rash two weeks later. The blisters have crusted over within a week from the appearance of rash. When is this child considered infectious?

Answer:
• The incubation period is 14 days (Jan 6 to Jan 19)
• The symptomatic period is 7 days (Jan 20 to Jan 26)
- The infectious period is probably 11 days (Jan 18 to Jan 28, as the patient with chickenpox is infectious from 1-2 days before the rash first appears to 1-2 days after the final crop of blisters have crusted over).
• The latent period is 12 days (Jan 6 to Jan 17)

Case definition:
It is a set of uniform criteria used to define a disease for surveillance purpose. Case definition in an outbreak situation can be divided into three categories:
- Suspected/possible case: clinical signs and symptoms without epidemiologic link or laboratory confirmation
- Probable case: clinical signs and symptoms with epidemiologic link (been exposed to a confirmed case, eaten the same food, stayed in the same ward, etc.) To a confirmed case
- Confirmed case: the diagnosis is confirmed by appropriate laboratory analysis of appropriate specimen(s) with or without clinical signs and symptoms and epidemiologic link
Index case:
The first case among a number of similar cases that are epidemiologically related
Case finding:
It is a method of identifying patients with healthcare-associated events (infection/colonization) through a combination of reviewing medical records, asking questions directed to patients or HCWs, and checking laboratory, imaging, or other relevant data, if available.
Environmental sampling:
It is the collection of samples from the health care environment or equipment (rather than from humans) that are cultured for microorganisms.

Levels of disease occurrence:
- Sporadic level: occasional cases occurring at irregular intervals
• Endemic level: persistent occurrence with a low to moderate level
• Hyperendemic level: persistently high level of occurrence
- Epidemic or outbreak: occurrence clearly in excess of the expected level for a given time period and location
- Pandemic: epidemic spread over several countries or continents, affecting a large number of people.

Levels of disease occurrence:
<table><tr><td>Level</td><td>Example</td></tr><tr><td>Sporadic disease</td><td>A Single case of rabies was diagnosed in a community.Records showed another 6 cases over the last 2 years.The duration between cases ranged between 2 and 8 months.Therefore, rabies spread sporadically in this community.Similar examples in Saudi Arabia, rubella, tetanus, and MERS-CoV</td></tr><tr><td>Endemic disease</td><td>Every year between 2010 and 2020, about 7 to 11 thousand tuberculosis cases were reported in the US (the rate ranged between 2.2 to 3.6 per 100,000).Therefore, tuberculosis is an endemic disease in the US.Similar examples in Saudi Arabia, hepatitis-B, salmonellosis, brucellosis, and tuberculosis</td></tr><tr><td>Hyperendemic disease</td><td>The Average annual incidence was 364 cases of pulmonary tuberculosis per 100,000 populations in one Indian city, compared with national average of 188 cases per 100,000 populations.Therefore, pulmonary tuberculosis is hyperendemic in that city.Similar example in Saudi Arabia, hepatitis B in Jeddah is approximately 31.5 per 100,000 while the national average in 19.8 per 100,000.Therefore, hepatitis B is hyperendemic in Jeddah.</td></tr><tr><td>Epidemic disease</td><td>Health authorities detected 22 cases of legionellosis occurred within 3 weeks among residents of a particular neighborhood (that usually report 0 or 1 case per year).Therefore, an epidemic of legionellosis can be declared.Similar examples in Saudi Arabia, COVID-19, influenza, chickenpox, and MERS-CoV</td></tr><tr><td>Pandemic disease</td><td>More than 20 million people worldwide died from influenza in 1918–1919.Pandemics of influenza were re-recorded again in 1957, and 1968, and 2009.Currently, COVID-19 is considered the biggest pandemic in the current century.</td></tr></table>

Health care-associated infection (HAI):
- It is an infection that occurs in a patient as a result of care at a healthcare facility that was not present at the time of admission to the facility.
- To be considered an HAI, the infection must be diagnosed after the patient spends more than two calendar days in the healthcare facility. Therefore, HAI can be diagnosed on or after the third day of admission, considering admission on the first day). For example, if admitted Sunday, HAI cannot be diagnosed on Sunday or Monday, and the first acceptable diagnosis of HAI will be Tuesday or after. Note that we are using calendar days (Sunday, Monday, ...etc.). In HAI determination (>2 calendar days).
- The term “healthcare-associated infection” replaces the formerly used “nosocomial” or “hospital” infection because evidence has shown that these infections can affect patients in any setting where they receive health care.
- It should be noted that HAI and outbreaks are two different terms.
- Therefore, HAI is not necessarily to be an outbreak (when detected sporadically).
- Additionally, an outbreak can be due to HAI or non-HAI events (when community infections become the source of in-hospital outbreak).
- Prevention measures should be implemented for any detected HAIs, whether outbreak or not
Outbreak:
- It is the disease occurrence in a population above the normally expected rates at any given time or location.
- The expected number of cases can be determined through ongoing disease surveillance.
- This involves the systematic collection of numerator and denominator data using standardized case definitions and surveillance methods.
Healthcare-Associated Outbreak:
- It is an increase in the number of healthcare-associated events (infection/colonization) among patients or staff over and above the expected number of cases.
- Healthcare-associated outbreak is met when there are two or more cases of infection/colonization caused by the same organism, epidemiological linked to the location, exposure, and duration. See below.
- When outbreak definition is met, record all involved patients, irrespective they have infection or colonization, caused by sensitive or resistant organisms, or meet the definition of HAI or community-related infection. See Presentation by onset time and by symptoms.
- Once the healthcare-associated outbreak is met, notification process should be started according to the steps described in the Operation of Outbreak

Epidemiological linked cases
- Epidemiologically linked locations: Cases involved in the outbreak shared the same unit or stop in one unit (example radiology section) during the course of hospital stay
• Epidemiologically linked exposure:
○ Human to human transmission: Any person who has had contact with a laboratory-confirmed human case in such a way as to have had the opportunity to acquire the infection
○ Environmental exposure: Any person who has contact with a contaminated environmental source that has been laboratory confirmed
○ Exposure to a common source: Any person who has been exposed to the same common source or vehicle of infection as a confirmed human case
- Epidemiologically linked duration: The duration varies from one infection to another based on the incubation period of different organisms or diseases.
- Outbreaks in healthcare facilities are often multifactorial, including branches in infection control or clinical practices, contaminated devices, and infected or colonized patients and/or HCWs.
- For more details, see Outbreak Classification Matrix- Class A Outbreak Classification Matrix- Class B Outbreak Classification Matrix- Class C
Emerging infections:
- In some rare, emerging and re-emerging diseases, and high-risk pathogens, one pathogen is enough to declare an outbreak in healthcare facilities that unlikely to be affected by that type of pathogens e.g., MERS-CoV, Monkeypox, and Ebola.... etc.
- Emerging infectious diseases are defined as infectious diseases that are newly recognized in a population or have existed but are rapidly increasing in incidence or geographic range.
- Zoonotic pathogens cause most emerging infectious diseases.
- Factors contributing to EID include population growth, spread in health care facilities, aging population, global travel, and changing vector habitats related to climate change.
- It should be noted that a disease that can be considered emerging/reemerging in one country is not necessarily considered emerging/reemerging. For example, dengue fever is considered emerging/reemerging disease in the US, while it is endemic in certain cities of Saudi Arabia, such as Jeddah and Makkah
• A list of emerging infections is shown in Appendix-2: Emerging Infectious Diseases.

Chain of infection:
The chain of infection is a model to display interconnected steps that describe how a pathogen is causing an infection. The chain of infection includes:
- Infectious Agent is a pathogen (germ) that causes diseases.
- The reservoir includes places in the environment where the pathogen lives (this includes people, animals and insects, medical equipment, and soil and water)
- Portal of exit is the way the infectious agent leaves the reservoir (through open wounds, aerosols, and splatter of body fluids, including coughing, sneezing, and saliva)
- Mode of transmission is the way the infectious agent can be passed on (through direct or indirect contact, ingestion, or inhalation)
- Portal of entry is the way the infectious agent can enter a new host (through broken skin, the respiratory tract, mucous membranes, and catheters and tubes)
- A susceptible host can be any person (the most vulnerable of whom are receiving healthcare, are immunocompromised, or have invasive medical devices including lines, devices, and airways)

Infectious Agent (pathogen):
- Infectious agents are microorganisms with the ability to cause disease:
• Bacteria: tuberculosis, plague, or anthrax
- Viruses: influenza, yellow fever, or AIDS
• Fungi: candidiasis or histoplasmosis.
- Parasites: malaria and toxoplasmosis
Mode of infections:
• Endogenous infections: caused by body flora in immuno-compromised patients
- Exogenous infections: caused by organisms from the outside environment

Ability to survive:
- The ability of the agent will remain viable in the environment until contact with the host, which is affected by:
- Ability to resist the effects of heat, drying, UV light, and chemical agents, including antimicrobials (See Appendix-3: Survival of Microorganisms)
- Ability to compete with other microorganisms
- Ability to independently multiply in the environment or to develop and multiply within another (vector) host
Infectivity:
- The capacity of an agent to enter and multiply in a susceptible host producing infection or disease, is affected by:
• The virulence: ability to grow and multiply
• The invasiveness: ability to enter the tissue
- Pathogenicity: the ability to cause clinical disease in the infected host
• Toxigenicity: ability to produce toxins
- Dose: number at the entry site of the host
Resistance:
- The ability of an agent to survive adverse environmental conditions (hepatitis agents are generally very resistant, whereas influenza viruses are typically fragile). Note: “resistance” is also applied to the host.
Antigenicity:
- An agent can induce antibody production in the host. (e.g., re-infection with the measles virus is very rare).
- The related term “immunogenicity” refers to an infection’s ability to produce specific immunity.

A reservoir of infection:
- Any animate or inanimate niche in the environment in which an infectious agent may survive and multiply to become a source of transmission to a susceptible host
- The reservoir typically harbors the infectious agent without injury to itself and serves as a source from which other individuals can be infected.
- The infectious agent primarily depends on the reservoir for its survival.
- It is from the reservoir that the infectious substance is transmitted to a human or another susceptible host.
• Examples from a healthcare setting
○ Human reservoir
√ Healthcare worker carriage of staphylococci in the anterior nares: methicillin-resistant Staphylococcus aureus (MRSA) in the nares, groin, or axilla of patients
○ Inanimate reservoir
√ Pseudomonas species or Legionella in air-conditioning humidification systems
√ Clostridium difficile spores on inpatient work surfaces
√ Serratia marcescens growing in contaminated soap or hand lotion preparations
Mode of transmission
- Mode of transmission is the method of transfer by which the organism moves from host to susceptible individual
• Transmission could be direct or indirect
<table><tr><td>Direct</td><td>Indirect</td></tr><tr><td>· Droplet contact: coughing or sneezing (1 meter)· Direct physical contact: to infected person secretions, blood, stool/urine (This method includes sexual contact)· Trans-placental infection: from mother to the fetus</td><td>· Airborne transmission: if the microorganism can remain in the air for long periods (TB, varicella, measles)· Indirect contact: usually by touching contaminated surface· Fecal-oral transmission: usually from contaminated food or water sources· Vector borne transmission: carried by insects or other animals· Iatrogenic Transmission: Transmission due to contaminated medical procedures</td></tr></table>

Mode of Transmission with examples
<table><tr><td>Type of transmission</td><td>Disease/pathogen</td></tr><tr><td>Airborne transmission○ Transmission via aerosols (airborne particles &lt;5μm) that contain organisms in droplet nuclei or in dusts○ Can spread via ventilation systems○ Precautions: Single negative pressure room and respirator (e.g. N 95) mask</td><td>○ Tuberculosis○ Chickenpox○ Measles○ Herpes zoster○ SARS○ Smallpox○ Pulmonary plague○ Legionella○ Fungal spores</td></tr><tr><td>Droplet transmission○ Transmission via sneezes or coughs○ Also can happen during suctioning○ Droplets are relatively large (&gt;5 μm) and can be projected up to about one meter○ Precautions: Masks, cover mouth, stand clear, and other droplet precautions</td><td>○ Bacterial Meningitis○ Respiratory viruses○ Influenza○ Mumps○ Whooping cough○ Diphtheria○ Group A streptococcus○ MERS-CoV</td></tr><tr><td>Fecal-oral transmission○ Transmission via ingestion of contaminated food and water drinks○ This included some victor-borne, swimming pools and even oral sex○ Precautions: hand hygiene, food sanitations, adequate sewage treatment, water chlorination, cleaning, and proper hygiene.</td><td>○ Rotavirus○ Enteroviruses○ Clostridium difficile○ Hepatitis A○ Poliomyelitis○ Cholera○ Salmonella○ Shigella○ Parasites</td></tr></table>

<table><tr><td>Type of transmission</td><td>Disease/pathogen</td></tr><tr><td>Waterborne transmission○ Ingestion of contaminated water○ Contact with or the inhalation of aerosols○ Precautions:○ Water disinfection and shock treatment○ Periodic cleaning and maintenance of showers, baths and sinks○ Installing disinfection systems and filters○ Avoiding the installation of other potential sources of infection such as decorative pools and fountains.</td><td>○ Pseudomonas aeruginosa,○ Legionella pneumophila○ Burkholderia cepacia○ Stenotrophomonas maltophilia○ Acinetobacter○ Non-tubercular mycobacteria</td></tr><tr><td>Direct contact transmission○ Direct physical contact between infected or colonized individual and susceptible host○ Examples of transmission: touching, kissing, sexual contact, contact with oral secretions, or contact with body lesions○ Precautions: Hand hygiene, masks, &amp; condoms</td><td>Sexually transmitted diseases○ HIV/AIDS○ Chlamydia○ Genital warts○ Gonorrhea○ Hepatitis B○ Syphilis○ Common cold○ Ebola</td></tr><tr><td>Indirect contact transmission○ Contact with reservoir as contaminated surfaces or objects, or to vectors such as mosquitoes, flies, mites, fleas, rodents or dogs○ No direct human-to-human contact○ Precautions: Sterilizing instruments, disinfect surfaces, and other contact precautions</td><td>○ MDRO○ MRSA○ VRE○ Gram negatives○ RSV○ Norwalk virus○ Rhinovirus</td></tr></table>

<table><tr><td>Type of transmission</td><td>Disease/pathogen</td></tr><tr><td>Vector borne transmission○ Transmission may be mechanical or biologic transmission○ Mechanical vector such as housefly can cause food-born diseases○ Biological vectors such as mosquitoes and fleas are often responsible for blood-borne diseases○ Precautions: barriers (window screens, bed nets), insect sprays, killing animals</td><td>○ Mosquitoes○ Dengue fever○ Rift Valley fever○ Yellow fever○ Malaria○ West Nile fever○ Sandflies○ Leishmaniosis○ Fleas○ Plague○ Rickettsiosis○ Aquatic snails○ Schistosomiasis</td></tr></table>
Susceptible host:
- Susceptible Host: A person who cannot resist a microorganism invading the body, multiplying, and resulting in infection.
- A combination of host defense reductions and an agent's ability to cause infection are typical of the acquisition of opportunistic infections in immunocompromised patients.
- Intrinsic or extrinsic factors influence the susceptibility and response of a host to an agent

Body's Defense Mechanism
- Barriers: intact skin, tears of eyes, cough, sneeze, respiratory cilia, stomach acids, and vaginal secretions
- Immune response:
√ Non-specific: neutrophils and monocytes
√ Specific: cellular (T cells) and humoral (B cells)
<table><tr><td>Intrinsic factors</td><td>Extrinsic factors</td></tr><tr><td>○ Age at infection○ Sex○ Race○ Nutritional status○ Birth weight○ Comorbid conditions○ Immune status○ Immunosuppression associated with other infections, diseases, or therapy○ Vaccination or immunization status○ Previous experience with this or similar agents○ The psychologic state of the host</td><td>○ Invasive medical or surgical procedures○ Medical devices, such as intravenous catheters, urinary catheter, or mechanical ventilators○ Duration of antimicrobial therapy○ Duration of hospitalization○ Exposure to hospital personnel.○ Sexual practices and contraception○ Behavior as smoking or alcohol intake</td></tr></table>
Breaking the Chain of Infection:
1. Control or elimination of infectious agents:
√ Rapid identification and isolation of source
√ Applying barrier precautions
√ Disinfection and sterilization of items and equipment
√ Environmental cleanliness
2. Control of reservoir:
√ Using disposable equipment
√ Disinfection and sterilization of non-disposable equipment
√ Identifying and controlling infections in carriers
3. Control of Portal of Exit:
√ Proper control of secretions and excretion
√ Environmental sanitations (waste disposal)
4. Control of transmission:
√ Hand hygiene
√ Source isolation
√ Aseptic techniques and proper device care
√ Control of air flow

√ Proper food handling
√ Environmental sanitations
5. Control of Portal of Entry:
√ Aseptic techniques and proper device care
6. Control of susceptible host:
√ Identifying high risk patients
√ Treating underlying disease
Herd immunity:
- Herd immunity is indirect protection from an infectious disease that happens when a population is immune through vaccination or immunity developed through the previous infection.
- Once a high proportion of all people in the community are immune, the likelihood is small that an infected person will encounter a susceptible person.
- Achieving herd immunity for a specific disease limits the probability of an outbreak of that disease and, if it happens, makes its control much more manageable.
• For herd immunity to work,
- Disease agents must be restricted to a single host species, and
- Transmission must be relatively direct from one member of the host species to another (e.g., no reservoir outside the human host in which the organism can exist, such as birds or mosquitoes)
- Herd immunity operates when there is random mixing of the population.
- The percentage of people who need to be immune in order to achieve herd immunity varies with each disease. For example, herd immunity against measles requires about 95% of the population to be vaccinated. The remaining 5% will be protected by the fact that measles will not spread among those who are vaccinated. For poliomyelitis, the threshold is about 80%. The remaining 20% will be protected by the fact that polio-myelitis will not spread among those who are vaccinated.
- Herd immunity does not apply to all diseases. For example, herd immunity against COVID-19 probably cannot be achieved because the virus continually changes its phenotype (therefore, new variants can escape immunity derived from infections and vaccines). Moreover, neither infection nor vaccination appears to induce prolonged protection against COVID-19 in many or most people.

Levels of prevention:
Primary prevention:
- Measures are taken to prevent the development of a disease in a person who is well and does not have the disease in question (by eliminating or reducing the disease risk factors)
• Example: immunizing a healthy baby against infectious diseases
Secondary prevention:
- Through screening and early intervention, measures are taken to identify people who have already developed the disease at an early stage in the disease’s natural history.
• Example: Surveillance culture to detect MRSA carriers to reduce HAI in ICU patients
Tertiary prevention:
- Measures taken to care of persons with already established disease, with attempts made to restore to highest function, minimize the negative effects of a disease, and prevent disease-related complications.
• Example: Treating pulmonary tuberculosis to prevent complications and restore workability

Steps of investigation of an outbreak
Steps of initial investigation of an outbreak
1. Recognize potential outbreak
2. Confirm presence of outbreak
3. Alert key individuals
4. Perform literature review
5. Establish a preliminary case definition
6. Develop method for case findings
7. Perform descriptive epidemiology
8. Implement initial control measures
9. Identify potentially implicated health practices
10. Consider environmental sampling
11. Communicating Information about Outbreaks
Steps of follow up investigation of an outbreak
1. Refine the case definition
2. Continue case finding
3. Review regularly control measures
4. Consider if analytic study should be performed

Steps of the initial investigation of an outbreak
1- Recognize potential outbreak:
A potential outbreak may be identified by:
1. Laboratory reports
- Frequently involves the identification of a particular organism in a number of clinical isolates that exceeds the expected baseline from a specific setting or within a specific period of time
2. Surveillance system.
- Such as infection control surveillance and communicable disease surveillance
- However, since targeted surveillance has rarely done continuously in the same place, the possibility of regular surveillance to detect surveillance is low
3. Front-line HCWs (nurses and physicians working in the affected unit)
- Many outbreaks are first recognized by front-line HCWs who recognize
- Increase in infections or deaths or identification of an unusual pathogen
• Un-common anatomic site of infection
- Unusual organisms, or infections occurring within a special subpopulation or specific location in a facility
Using advanced laboratory technologies in outbreak identification:
- Whole genome sequencing (WGS): It provides highly supported phylogenetic trees and has become the new reference standard for bacterial typing. WGS provides detailed and precise data for identifying outbreaks cause. Additionally, WGS is used to characterize bacteria as well as track outbreaks
- Pulsed-field gel electrophoresis (PFGE): It is a laboratory technique used by scientists to produce a DNA fingerprint for a bacterial isolate. A bacterial isolate is a group of the same type of bacteria. It has been used to determine epidemiological links between bacterial isolates
Note: Advanced laboratory technologies can help in outbreak identification. However, they are not necessarily available to diagnose an outbreak. Most of outbreaks are detected in hospitals that do not have these advanced laboratory technologies

2- Confirm the presence of the healthcare-associated outbreak
How to confirm the presence of outbreak:
- Compare the observed (the current) number of cases with the expected (previous) number of cases (same location and period)
• To detect the occurrence of more cases of disease than expected
Sources expected rates:
- Laboratory reports: for some pathogens, like Klebsiella pneumonia and Pseudomonas aeruginosa.
- Local hospital discharge records or local mortality statistics for hospitalized infections
• Ministry of Health (MOH) surveillance reports for notifiable disease
- If local data are unavailable, you may conduct a telephone survey of physicians to determine whether they have seen more cases of the disease than usual.
Pseudo-outbreak:
- It is generally applied to situations with a rise in positive laboratory findings (e.g., positive microbiology cultures) without a similar increase in the number of related clinical cases.
- It may also be caused by a change in the surveillance system/ laboratory methods resulting in the misclassification of non-infected cases as infection or identification of cases that were always present but previously missed by surveillance.
Causes of rising positive laboratory findings:
1- Laboratory factors
- Introduction of a new test, which was previously unavailable locally.
- Improving laboratory techniques for identification.
- Introduction of new laboratory tests with poor specificity and/or sensitivity.
- Contamination during laboratory processing, e.g., contamination of media or cross-contamination of a specimen during processing.
2- Non-laboratory factors.
- Incorrect diagnosis of the clinical entity
- Contamination during collection if the correct procedure for the collection of specimens is not followed
- Use of water of poor microbiological quality in the washer-disinfectors. Example. Misdiagnosis of tuberculosis has been reported due to contamination of the endoscope with environmental mycobacteria (e.g., Mycobacterium chelonae) from the rinse water

Example of rising positive laboratory findings:
- Several pseudo-outbreaks of bloodstream infection have been reported (increase in laboratory positive blood culture not parallel to clinically diagnosed bloodstream infection) due to contaminated culture media, contaminated antiseptics, contaminated blood culture vials, or inadequate disinfection of the analyzer.
Causes of overcalling cases:
• Changes in local reporting procedures
• Changes in the case definition
- Increased interest because of local or national awareness
- Improvements in diagnostic procedures
If, after investigation, an outbreak is not confirmed, then the IPC team must inform the clinical team who have reported the outbreak and provide reassurance.
3- Alert key individuals
- It is important to make supervisors and hospital leadership aware of the presence of an outbreak situation so that resources can be made available and communication with staff and the community can be managed.
- In addition, the microbiology laboratory and staff working in the area where the outbreak is occurring should be alerted to look out for new cases and to collect and save the appropriate samples for investigation.
- Alerting key individuals in the hospital are essential to halting hospital outbreaks, especially those of large-scale, serious outbreaks and those that need unusually high resources
Example of alerting key individuals:
- After confirming the presence of the Burkholderia Cepacia outbreak in one of the big tertiary care hospitals, the IPC staff communicated the early finding to the healthcare workers and hospital administration to stop using chlorhexidine which was confirmed to be the contaminated solution. Additionally, a notice was sent to the Saudi Food and Drug Administration (FDA) to withdraw the product from all other hospitals
- After confirming the presence of a carbapenem-resistant Enterobacterales outbreak in one of the hospital wards, the IPC staff communicated the early finding with healthcare workers in other units to take extra measures to prevent the spread of the outbreak into their units.
- Early during the COVID-19 pandemic, the outbreak management team alerted the hospital administration in one of the big tertiary care hospitals about the shortage of staff and supplies to levels that can impede the control measures in the near future. The administration reacted by stipulating several managerial orders to facilitate logistics and supply management. Adopting a central tracking and distribution system for personal protective equipment, creating surge capacity in unfavorable pressure rooms, establishing quarantine hotels, and training and up-skilling nursing staff in non-urgent units.

4- Perform a literature review
- Literature reviews help answer several questions about the current outbreak, especially in the case of rare pathogens such as Burkholderia Cepacia. For example, in previous similar outbreaks, what have been the sources, modes of transmission, and risk factors for the disease? Previously used sample questionnaires can be reused to detect new cases.
- A literature review can also guide the investigators in looking for the cause and providing strategies to stop the outbreak.
The following resources may be of help to those in limited-resource settings:
√ GDIPC website (https://gdipc.sa/)
√ Ministry of Health of Saudi Arabia (https://www.moh.gov.sa/)
√ Public Health Authority-Weqaya (https://covid19.cdc.gov.sa/)
√ Public Health Authority (https://od.data.gov.sa/Data/en/organization/about/weqaya)
√ National Library of Medicine (http://www.nlm.nih.gov/)
√ US Centers for Disease Control and Prevention (CDC) (www.cdc.gov/) provides abundant information ranging from current outbreaks and immunizations to disease-specific subject matter.
√ Worldwide Database for Nosocomial Outbreaks (www.outbreak-database.com)
√ The World Health Organization (WHO) Global Outbreak Alert and Response Network (http://www.who.int/ihr/alert_and_response/outbreak-network/en/).
5- Establish a preliminary case definition
➢ Develop a case definition which may include:
- Persons: description of affected individuals
• Time: range for when the illnesses occurred
- Place: geographic range, such as residency in a state or region
- Agent: pathogen or toxin, if known
• Symptoms: certain symptoms typical for that pathogen or toxin
<table><tr><td>Element</td><td>Descriptive Feature</td><td>Example</td></tr><tr><td>Laboratory</td><td>Pathogen, serotype</td><td>E. Coli O157:H7</td></tr><tr><td>Symptoms</td><td>Acute gastrointestinal tract (GIT) illness</td><td>3 or more loose stools in a 24 hour period</td></tr><tr><td>Person</td><td>Age group</td><td>Children under 5 years old</td></tr><tr><td></td><td>Sex</td><td>Males</td></tr><tr><td></td><td>Occupation</td><td>HCWs at hospital A</td></tr><tr><td></td><td>Exclusion criteria</td><td>Persons with chronic diarrhea</td></tr><tr><td>Place</td><td>Geographic location</td><td>Resident or visitor to ward B</td></tr><tr><td></td><td>Water source</td><td>Residents connected to water line C</td></tr><tr><td>Time</td><td>Illness onset</td><td>Onset of illness on or after January 1, 2020</td></tr></table>

Example of preliminary case definition
- Three cases of new HIV infection among hemodialysis patients at a hemodialysis unit in Saudi Arabia were investigated to determine if there was an HAI outbreak.
- The investigators developed the following case definition:
- A case was defined as a patient among those undergoing treatment at hemodialysis unit 1, during November and December 2011. They seroconverted to HIV-positive status, and their self-reported behaviors did not include HIV risk factors, and their spouse was seronegative for HIV.
Categories of case definition:
<table><tr><td>Case category</td><td>General features</td></tr><tr><td>Confirmed</td><td>Laboratory confirmation of agent</td></tr><tr><td>Probable</td><td>Typical clinical features of illness AND Partial laboratory results (confirmation pending) OR Epidemiologic link to a laboratory-confirmed case</td></tr><tr><td>Suspected</td><td>Typical clinical features of illness AND Missing laboratory and epidemiologic information</td></tr></table>
Primary versus secondary cases
- It is important to distinguish between primary and secondary cases.
- Primary cases are directly exposed to the outbreak source. In contrast, secondary cases are defined as individuals who contracted the illness through exposure to a primary case rather than the outbreak source (e.g., household contacts who become infected).
- Secondary cases should be included in defining the scope of the outbreak but are not included in an analytic study to identify the source of the outbreak; only.
- Primary cases would be included in a study.
- For example, studies were done to see how many exposed households get COVID-19 infection. It was found that 15% of households became secondary cases in the 14 days since the last unprotected exposure to the primary case.
- Another example was the MERS-CoV outbreak in one of the large tertiary care hospitals; it was found that primary cases (admitted with the infection from the community) were 20% while secondary cases (got the infection in the hospital from primary cases) were 80%. Secondary cases were less likely to infect patients than primary ones, which helped completely control the outbreak after enforcing infection control practices. Few primary cases spread the infection to a large number of secondary patients (called super-spreader)

Sensitivity versus specificity in a case definition
- Ideally, a case definition will include all cases (high sensitivity) but exclude any person who does not have the illness (high specificity).
- A sensitive case definition will detect many cases (true positives) but may also count as cases of individuals who do not have the disease (false positives).
- A more specific case definition is more likely to include only persons who truly have the disease under investigation (reduce false positives) but also more likely to miss some cases (false negatives).
- There are no rules about how sensitive or specific a case definition should be.
- At the start of an outbreak, use a broad case definition (more sensitive) and then narrow the case definition down (more specific) at a later date when more information is available from the clinical and laboratory investigation.
<table><tr><td></td><td>Sensitive case definition</td><td>Specific case definition</td></tr><tr><td>Advantages</td><td>Increase chances of finding cases (“true positives”); able to find as much information on true cases early on, rather than having to go back and find cases later.</td><td>Improve case classification (i.e., minimize “false positives”); strengthen subsequent analytical tests or studies; may be more resource efficient.</td></tr><tr><td>Disadvantages</td><td>May capture individuals who are not actually part of the outbreak (“false positives”); may be resource intensive.</td><td>May miss cases (“false negative”).</td></tr><tr><td>Example</td><td>In the peak of an outbreak of chickenpox, case definition can be “any generalized rash illness of acute onset.” This sensitive definition can detect all chickenpox cases (true positive) but also cases with similar disease as measles, rubella, and drug allergies (false positive).</td><td>When the number of cases is reduced and the resources became available, more specific case definition can be used “positive PCR test to detect Varicella-zoster virus in skin lesions”. It will not report similar disease (false positive) but may miss some chickenpox cases who are tested towards the end of the disease (false negative)</td></tr></table>

6- Develop a method for case finding
Methods of case finding:
- The investigator conducts a planned search for cases using case definitions to identify new or additional cases of an infection or disease.
- Looking both backward and forward in time may be necessary to identify new cases as well as additional cases from the past using the time frame in the case definition.
- Signs and symptoms of the infection or positive laboratory results from the case definition may be used to trigger a further investigation to see if a patient matches the case definition.
- A simple data collection form (line list) is usually developed to collect information on possible cases.
- The line list may include a few variables or be comprehensive. The benefits should be weight against the efforts required to collect the data.
- The line list data will be used in plotting the epidemic curve later.
Sources for cases findings:
- Assemble the information from medical charts, microbiology reports, pharmacy reports, and logbooks from affected areas.
- Surveillance culture for high-risk groups. However, benefits should be weight against the cost. This may be done for a short period to determine the burden of colonized patients, which will help you decide whether to extend the surveillance culture or not.
- Reviewing regular surveillance reports
- Asking local clinical and laboratory professionals to report cases of the particular illness more quickly, as soon as they suspect the diagnosis
- Reviewing emergency room records for similar illnesses
- Sometimes, alert the public to seek medical advice if they have symptoms compatible with the case definition.
Data variables to be collected:
• These data may vary from outbreak to outbreak but may include the following:
√ Identifying information: ID, name, and telephone number
√ Items from the case definition
√ Demographic information (age, sex, date, the reason for admission, diagnosis, date of surgery or procedures, antibiotics, etc.)
√ Location information (admission, discharge, and transfer)
√ Clinical data (onset of signs and symptoms, frequency and duration, treatments, medical devices)
√ Outcome information (hospitalization, ICU care, ventilator, and death).
√ Risk factor information: differ from disease to disease

7- Perform descriptive epidemiology
Descriptive epidemiology:
- Characterizing an outbreak by time, place, and person using an epidemic curve
• Calculating the attack rate
Epidemic curve:
- It plots the cases in an outbreak based on the time of onset of illness.
- Done by drawing a histogram of the number of cases (on the y-axis) by their date of onset (on the x-axis)
Advantages of the epidemic curve:
- Can identify the exact period of the outbreak
- Can identify the probable period of exposure
- Can determine the epidemic pattern; common source, propagated, or both
- When combined with other information gathered during the investigation, it can help identify the possible exposure.
Calculating the attack rate
- An attack rate is a form of incidence that measures the proportion of persons in a defined population who had an acute health event during a limited time period (e.g., during an outbreak).
- It is typically used in the investigation of acute outbreaks of disease, where they can help identify exposures that contributed to the illness (e.g., using Burkholderia-contaminated saline solution).
Attack Rate = \( \frac{\text{Number of new cases who got infected during the outbreak specified location and time interval}}{Population at the same location at the start of outbreak} \) X 100
- The attack rate can also be calculated stratified by relevant characteristics such as sex, age, location, or specific exposure (ventilation, catheterization, operating rooms, and occupational exposure).
- At the end of the descriptive analysis, it should be possible to:
√ Formulate a hypothesis on the type of infection (exogenous, endogenous)
√ Tentatively identify the source and route of infection
√ Suggest and implement initial control measures.

8- Implement initial control measures
Implement initial control measures
• Take action and implement infection control measures without delay.
• Full implementation of infection control measures as recommended by the IPC
• Special cleaning and disinfection procedures.
- Depending on the type of pathogen, incubation period, and susceptibility, consider the isolation of patients, staff, and visitors and initiate contact tracing as appropriate.
- Determine patients/staff at risk of becoming ill and offer the appropriate treatment, e.g., antimicrobial agents, active and/or passive immunization
- It is always appropriate to educate or reinforce HCWs about IPC precautions and to develop a plan to ensure ongoing compliance with them.
- Closure of catering facilities, if considered appropriate.
- Closure of health care facilities, if necessary.
- For the details of the control measures required according to the transmission type, see Appendix-4: Control measures.
9- Identify potentially implicated health practices (creating hypothesis)
How to identify potentially implicated health practices
- An outbreak can be stopped by identifying and interrupting the chain of transmission.
- Information from the literature review on the type of pathogen and infection, and a review of the cases in the line list, may help identify which healthcare practices to focus on.
- Discussing the outbreak and possible causes with staff is also essential.
- Investigations are more productive if investigators are seen as partnering with the staff rather than attempting to find someone to blame
- Observations should at first be done without a detailed data collection form and should focus on workflow and practices that are different from best practices, recommended IPC guidelines, and hospital policies.
- General IPC practices such as hand hygiene and Standard Precautions should be observed.
- It can be helpful to ask about shortcuts and methods that have been created by staff to work around perceived barriers to make workflow easier.
Examples of useful questions to ask during observations:
1. Exposure to a reusable instrument
√ Review of the facility’s reprocessing procedures for that instrument
2. Infections associated with indwelling devices
√ Review of procedures for the access and maintenance of these devices

3. MDRO
√ Assessment of staff adherence to hand hygiene and contact precautions, as well as cleaning and disinfection of high-touch surfaces and shared medical equipment
4. Environmental organisms (e.g., Aspergillus)
√ Review and observations of construction activities in or near patient areas
5. Waterborne pathogens (e.g., Legionella or Pseudomonas aeruginosa)
√ Assessment for potential routes of exposure to tap water
√ Review of local wound care practices, preparation, and handling of injectable or aerosolized medications (near vicinity of sinks)
6. Similar types of injectable medications among case-patients
√ Review of medication preparation and handling in the affected unit, central pharmacy, particularly if the medication was prepared or compounded onsite
7. Assessing environmental cleaning and disinfection
√ Fluorescent markers
√ Adenosine triphosphate (ATP) bioluminescence assay can also be used to detect residual organic material after cleaning
10- Consider environmental sampling
When to consider environmental sampling
- If environmental sampling is an option, cautious consideration should be given before deciding upon this course of action due to cost, lack of standards for interpretation, and the high possibility of inconclusive results (see Appendix-5: Environmental Sampling)
- Isolation of an organism from the environment rarely explains an outbreak.
- Environmental sampling should be pursued only if strong epidemiological evidence indicates a possible source or reservoir of organisms exists.
• Environmental sampling may not be possible due to a lack of lab capacity or supplies
- On the other hand, if environmental sampling is indicated and possible, a positive result matching the pathogen causing the outbreak can be very satisfying.
Interpreting negative environmental sampling
- It is important to note that if negative results occur, it will not be known if the environment can be ruled out or if the sampling failed for some reason.
- There are many reasons why sampling the environment might not reveal a source pathogen, even if it is present.
√ Inadequate collection or cultural technique
√ The pathogen was already removed by cleaning or only present transiently.
√ The sample was taken from the wrong place.

Recommendations that can improve environmental sampling:
- Perform these cultures after making the line list and doing observations so that they can focus on items that seem the most likely to be implicated. Environmental cultures should never be the first step in an outbreak investigation.
- Before obtaining any environmental cultures, talk with microbiology laboratory personnel to determine whether they are able to process the cultures that will be obtained and discuss the optimal methods of obtaining them.
• Culture-only items are possible vectors of transmission.
- Culture the items that make the most sense as the likely reservoir for the organism. For example, outbreaks of Pseudomonas should focus on liquid items, whereas outbreaks of Acinetobacter should focus on surfaces.
11- Communicating information about outbreaks
Communicate early:
- If an outbreak is identified, it is important to communicate early and clearly.
- Notification process should be started according to the steps described in the Operation of Outbreak
√ Meeting the MOH outbreak criteria of notification
√ New or emergent pathogen that is first identified in the healthcare facility
√ Outbreak with the source is suspected or traced to an iatrogenic
√ Outbreaks that are deemed not manageable by the facility
- Keep the staff, patients, relatives, and visitors informed and assured.
- Flag the electronic medical system in certain conditions (such as MDRO) to allow other staff to deal with the patient using appropriate infection control measures
- Communication between health care facilities in case of transfer to enable the receiving institution to put in place appropriate precautions.
- Communication between laboratory and clinicians to provide instant information about the organism and resistance
- Communication between pharmacy and clinicians to provide instant information about appropriate medication and to modify formulary if required
- It is also essential that the spokesperson, not the staff members, would communicate directly with the media.
Write preliminary and final confidential outbreak reports
- The report must summarize complete investigations, lessons learned, and recommendations to prevent a recurrence in the future.
- The report must be sent to the senior management and other appropriate personnel/authorities for action.

When to declare that the outbreak is over
- The point at which an outbreak can be declared over depends on the nature of the outbreak (type of microorganism).
<table><tr><td>Outbreak</td><td>Explanation</td></tr><tr><td>Healthcare-associated outbreaks</td><td>○ There are no new cases epidemiologically linked to the relative outbreak are identified within 14 days from the last outbreak case (the last case included in the outbreak should be either negative, discharged, or deceased)○ The declaration of outbreak end must be arranged with GDIPC</td></tr><tr><td>Ebola outbreak</td><td>○ No confirmed or probable Ebola cases are detected for a period of 42 days (i.e. twice the maximum incubation period for Ebola infections) since the death/recovery of the last confirmed case</td></tr><tr><td>MERS-CoV outbreak</td><td>○ No confirmed MERS-CoV cases are detected for a period of 28 days (i.e. twice the maximum incubation period for MERS-CoV infections) since the death/recovery of the last confirmed case</td></tr><tr><td>Cholera</td><td>○ No new cases reported for 7 weeks</td></tr><tr><td>Meningitis</td><td>○ Weekly number of reported cases below the “epidemic and alert threshold” for 8 weeks</td></tr></table>
Source: https://doi.org/10.1093/aje/kwaa212

Steps of follow-up investigation of an outbreak
1. Refine the case definition:
- As the outbreak continues, the outbreak case definition may need to be refined
- We can refine the case definition with the new information available with time or with additional diagnos

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