Development of Outbreak Investigation Database for hospital Infections

Osaka University, Osaka University,

Faculty of Medicine, JAPANFaculty of Medicine, JAPANKiyoko Makimoto, Ph.D.,

MPH

What are hospital infections?

• Two types of infections you find in the hospital– Hospital-acquired infections– Community-acquired infections

• How can we distinguish them?– By latency period– CDC definition for NIs: developm

ent of infections after 48 hours of admission

Brief history of hospital infections• First well documented hospital infections

– In the middle of 1800 Lying-in Hospital in Vienna – Maternal mortality rates exceeded 10%, mainly

due to puerperal fever (child-bed fever) endemic

• Modern epidemiology of hospital infections– In 1950s, Staphylococcus aureus infection

outbreaks in hospitals all over the world

• Advances in 1970• Intensive research in the 1990s

What kinds of hospital infections exit?

• Device-related– Blood stream infections (BSI)– Urinary tract infections (UTI)– Ventilator-associated pneumonia (VAP)

• Procedure-related– Surgical site infections (SSI)

• Environmental contamination– Water, disinfectant, etc.

Devices and procedures as major sources of hospital infections

Surgeries

Arterial/venous catheters

Urinary catheters

Respirators

Cross-infections: 20-

40%

Changes in flora due to antibiotic therapy :20-25% Others

:　 20%

Patients’ own flora:

40-60%

Why do we need to study hospital infections?

Not all hospital infections are preventable, but they are associated with

• Excess length of hospital stay

• Excess cost

• Excess mortality

• Law suits

Distribution of hospital infections by sites, SENIC study

Urinary tract

Surgical wound

Pneumonia

Bacteremia

Other sites

Increases in the mean length of hospital stay due to hospital infections

in the U.S. , SENIC study

Days0 1 2 3 4 5 6 7 8

All

Other sites

Urinary tract

Pneumonia

Surgical wound

Bacteremia

Excess cost of hospitalization due to hospital infections in the U.S., 1992

0 1000 2000 3000 4000 5000 6000

All

Other sites

Urinary tract

Surgical wound

Bacteremia

Pneumonia

U.S. dollars

Who are at risk for acquiring hospital infections?

• Patients in Intensive Care Units– ICU （medical, surgical, burn, Neonatal

ICU、 Pediatric ICU)– Surgery department

• Immunocompromised patients– Cancer treatment, transplant, HIV infections

• Other factors– Age, smoking, chronic diseases

Distribution of hospital infections by infection sites and

endemic/outbreak status

Urinary tractSurgical woundPneumomiaHepatitisGastroenteritisCutaneousBacteremiaOther

EndemicOutbreak

Why do we need an outbreak investigation database?

• Literature search is considered essential for outbreak investigation

• Difficulty in collecting relevant articles in hospitals with limited resources

• Shortage of health care workers trained in epidemiology in Japan

• Epidemiology of hospital infections is not taught in school

Conducting Medline search

• Medline search yielded >600 articles between 1970 and 2000

• Only a small number of outbreak investigations reported all the information necessary to replicate the investigation

• Recent investigations tend to focus on DNA typing to identify epidemic strains

What kinds of outbreaks have been reported?

• The largest number of people affected– Norwalk-like virus affected 635 employees (27%

attack rate), 79 people affected in a single day– Am J Epidemiol. 1988 Jun;127(6):1261-71.

• The longest duration– >= 10 years of unrecognized hospital

transmission of legionnaires' disease among transplant patients (25 cases)

– Infect-Control-Hosp-Epidemiol. 1998 Dec; 19(12): 898-904

Continued• Unusual source of outbreak

– Klebsiella pneumoniae producing ESBL transmitted by gel used for ultrasonography

– 2 adults and 1 neonates were infected; 5 colonized

– J-Clin-Microbiol. 1998 May; 36(5): 1357-60

• Outbreak due to non-infectious origin– Hemolysis (discolored, pink serum visualize

d in spun serum sample) due to defect products (30 cases in 11 days)

– Kidney-Int. 2000 Apr; 57(4): 1668-74

What kinds of fields do we need?

• Mode of transmission• Pathogens• Type of investigation• Place (NICU, ICU,

surgery, etc.)• Country• Author

• Hospital size• No. of patient affected• No. of deaths• Detail investigation

process• Infection control and

prevention strategies

Usefulness of the Database I

• A learning tool for epidemiologic and microbiologic investigations

– Specific pathogens to look for in certain symptoms

– Guide epidemiologic investigations• Identify study design in similar situations• Types of information to collect

Epidemiologic skills required in complex investigations

• Case definition

– Able to learn how to write a case definition to find cases

• Selection of controls in case-control studies

– Selection of controls is the most difficult part

Usefulness of the Database II

• Provide infection prevention strategies by– pathogens

– type of service

– infectious diseases

– mode of transmission, etc.

Searching by Pathogens: Acinetobacter

baumannii

Any impacts of the database on Japanese culture?

• Very few Japanese professionals report outbreak investigations

• Reporting outbreaks to professional journals as professional and social obligation

• Providing information in sufficient detail to help investigations

Challenges

• Currently 220 records have been entered

• Changes in hospital practices affecting the outbreak investigation

• Funding is necessary to complete and keep updating outbreak database

Changes in hospital practices

• Factors related to patients– Shorter hospital stay– Increased patients’ acuity– Increases in intra- and inter-hospital transfer

• Factors related to health care workers– High turnover of nurses– Floating shift– Employment of temporary staff

Your comments are greatly appreciate it

URL for the outbreak investigation database

http://health-db.net/infection/index.asp