Jurai Wongsawat, M.D. Bamrasnaradura Institute Nonthaburi, Thailand

1. MRSA Infection control & outbreak investigation Jurai Wongsawat, M.D. Bamrasnaradura Institute Nonthaburi, Thailand

2. Outlines • Mechanism of transmission • Prevention & Control • Outbreak investigation

3. Staphylococci • Hardiest non spore – forming bacteria • Relatively heat resistance • Can survive in environmental for several months • Children and adult up to 25% can be colonized

4. HOST Hemodialysis/ CAPD Injection drug users Dermatologic diseases DM Those who required repeated injections Liver disease HIV or other defect immune function Nasal abnormalities OTHER FACTORS Presence of invasive device Prior antimicrobial therapy History of antecedent colonization Increase chance of exposure - HCWs High risk - Colonization

5. Modes of transmission • Mainly via direct contact - hands of HCWs • Indirect contact - clothes, environmental surface, equipment • Airborne transmission - Staph pneumonia

6. Special problems • Epidemic vs endemic MRSA • Community acquired - skin and soft tissue infection - positive culture on admission or within 48 hours • Frequent antibiotic use

7. Problem of ATB use • Reducing use of second or third gen. cephalosporin can reduce rate of colonization/ infection ( Matsumara H, et al. Burns 1996;22:283-6) • Reduction use of many broad spectrum B-lactam ATB was associated with drop of MRSA cases ( Frank, et al. Clin Perform qual Health Care 1997;5:180-88) • Significant reduction in monthly number of MRSA following decreased use of cephalosporin, imipenam, clindamycin, vancomycin ( Landman D, et al. Clin Infect Dis 1999;28:1062-66)

8. Outlines • Mechanism of transmission • Prevention & Control • Outbreak investigation

9. Administrative - Surveillance - Hand hygiene policy - Antibiotic control program Engineering - Isolation room Protective equipments - Gown, gloves, mask Surveillance Isolation or cohort nursing & Encourage for hand hygiene Management of colonizers or carriers Tretment of infected patients Prevention Control

10. Advocated measures (1)

11. Advocated measures (2)

12. Surveillance • Laboratory based • Line listing of MRSA cases • Routine screening in patients is not recommended • Screening for high risk patients • Screen known cases upon readmission

13. Isolation or cohort nursing • Contact precaution • Isolation - not necessary if routine standard practice is in place - necessary for : MRSA respiratory tract infections : wounds that cannot be adequately covered

14. Hand hygiene (1) • The most important measure • Transmission decreased from 16.9% to 9.9% ( 2.16 to 0.93 episodes per 10,000 patient days) when hand hygiene improved from 48% to 66% ( Pittet et al) • Problem – low adherence

15. Hand hygiene (2) • The most important measure • Transmission decreased from 16.9% to 9.9% ( 2.16 to 0.93 episodes per 10,000 patient days) when hand hygiene improved from 48% to 66% ( Pittet et al) • Problem – low adherence

16. Hand hygiene (3) • A simple 10 second wash with soap and water shows an absence of MRSA on 96% of cultured individuals hand (Simmons B, et al) • Alcohol based hand rub - increase compliance

17. Management of colonizers or carriers • Consider during the outbreak • More likely to transmitt - skin lesion/dermatitis - persistent nasal carriage • Nasal screening - endemic with serious infection - outbreak

18. Decolonization • 2% mupirocin intranasal • Rifampin 600 mg bid for 5 days • Ciprofloxacin 750 mg bid for 14 days • Combination drug • High rate of recurrence at 1 mo

19. Treatment of infected patients • Parenteral glycopeptide therapy • Serum concentration should be monitored

20. Outlines • Mechanism of transmission • Prevention & Control • Outbreak investigation

21. Approach • Surveillance – problem, cluster • Determine existence of an outbreak - define case, compare preepidemic • Epidemiologic study - line listing, epidemic curve, risk factor study ( case control/ cohort) • Additional studies - reviews, culture surveys, isolate typing • Interventions/ control measures • Assess interventions

22. Elimination of Epidemic MRSA from a University Hospital and District Institutions, Finland • August 1991 – October 1992, two outbreaks in surgery & medicine • Screening policy after cases occurred - all pts, contact HCWs - nasal swab +other sites after 2 neg results – individuals were no longer screened • Subsequent admission - screen and isolate Kotilainen P, et al. Emerg Infect Dis 2003;9: 169 -75)

23. Elimination of Epidemic MRSA from a University Hospital and District Institutions, Finland • Identification - NCCLS - Typed with International phage set ( Phage typing) pulsed – field gel electrophoresis ( PFGE - molecular typing) • Elimination treatment Topical or combined – high risks gr. Kotilainen P, et al. Emerg Infect Dis 2003;9: 169 -75)

24. Elimination of Epidemic MRSA from a University Hospital and District Institutions, Finland Results • 202 were infected/ colonized • 15 strains - 10 outbreak strains - 5 community strains • IC measures - Intensive education of staff on hospital hygiene - single room isolation - strict adherence - screening all patients in outbreak ward - closed to new admission ( epidemic) • 20 staff members were colonized Kotilainen P, et al. Emerg Infect Dis 2003;9: 169 -75)

25. Conclusion • Aware of high risk patients • Early identification • Proper infection control measures • Good surveillance systems • Proper use of antibiotics

26. Thank you