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IN HOSPITAL EPIDEMIOLOGY AND INFECTION CONTROL

Chapter 32 Role of The Clinical Microbiology Laboratory in Hospital Epidemiology and Infection Control Hui Wang. IN HOSPITAL EPIDEMIOLOGY AND INFECTION CONTROL. Nosocomial infection : acquired in a hospital or healthcare facility

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IN HOSPITAL EPIDEMIOLOGY AND INFECTION CONTROL

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  1. Chapter 32 Role of The Clinical Microbiology Laboratory in Hospital Epidemiology and Infection Control HuiWang

  2. IN HOSPITAL EPIDEMIOLOGY AND INFECTION CONTROL Nosocomial infection : acquired in a hospital or healthcare facility an onset of symptom more than 48 hours after admission (shorter hospital stays) (eg. surgical wound infections ) may not be recognized until after discharge (postdischarge surveillance )

  3. EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(1) Main Infection Sites (5% to 10% of inpatients) UTI: urinary tract 35% to 40% SSI: surgical wound infections 20% LRI: lower respiratory tract 15% BSI: bloodstream infections 5% to 10% Devices related: various catheters, tubes, etc. Device days —risk adjustment of nosocomial infection rates (ICU)

  4. EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(2) Predominant Pathogens

  5. EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(3) Predominant Pathogens NNIS :ICU Jan 1986-Apr 1997

  6. EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(4) Predominant Pathogens NNIS :ICU Jan 1986-Apr 1997

  7. EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(5) NNIS, ICU, HA-Candidemia, 1989-1999

  8. The Hospital Infection Control Program surveillance of nosocomial infections continuing education of medical staff control of infectious diseases outbreaks protection of employees from infection advice on new products and procedures timely feedback of infection rates suggestions for improvement and reemphasis of existing infection control practices EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(6)

  9. The Hospital Infection Control Program Device days — risk adjustment of nosocomial infection rates (ICU) CAUTI: urinary catheter-associated urinary tract infection CLAB: central line-associated bloodstream infection VAP: ventilator-associated pneumonia EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(7)

  10. The Hospital Infection Control Program Surveillance -- essential Limited resources focused in the highest risk areas (ICUs, hematology-oncology, burn units, organ transplant wards) various screens : microbiology reports, nursing care plans, antibiotic orders, and discharge diagnoses EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(8)

  11. The Hospital Infection Control Program Review of microbiology reports ward-based, laboratory-based linking data from pharmacy (antimicrobial use) laboratory Radiology billing (diagnostic codesnursing notes (temperature charts, care plans) EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(9)

  12. The Hospital Infection Control Program sensitivity and specificity frequency of culturing quality of the specimens Optimal surveillance a combination of all the above data charts deserve further review EPIDEMIOLOGY CHARACTERISTICS OF NOSOCOMIAL INFECTIONS(10)

  13. MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION(1) Specimens Collection nosocomial pathogens colonizing organisms colonizing organisms

  14. Specimens Collection inappropriate specimens wrong transport media leaking containers undue delay from collection to transport accurate, least misleading microbiological data monitoring of specimen quality enforcement of strict criteria for acceptance MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION (2)

  15. MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION (3) Accurate Identification of Nosocomial Pathogens capability to identify microorganisms to species level Conventional identification methods automated commercial systems unusual nosocomial pathogens: send to a reference laboratory

  16. MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION (4) Accurate Identification of Nosocomial Pathogens

  17. MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION(5) Antimicrobial Susceptibility Testing • macro- and microbroth dilution method

  18. MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION (6) Antimicrobial Susceptibility Testing agar dilution method

  19. MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION(7) Antimicrobial Susceptibility Testing disk diffusion method

  20. MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION(8) Antimicrobial Susceptibility Testing Etest

  21. MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION(9) Antimicrobial Susceptibility Testing automated commercial systems short (3- to 5-hour) incubation periods significant AST errors ( ESBL-producing Enterobacteriaceae, MRS, VRE, VRSA, false resistance ) Supplement with additional methods keep up with current literature regarding the ability of automated systems

  22. Resistance Patterns Testing extended-spectrum β-lactamases (ESBL) stably derepressed Bush-Jacoby-Medeiros group 1 cephalosporinases among Enterobacteriaceae glycopeptide resistance among enterococci and staphylococci penicillin resistance among S. pneumoniae and viridans-group streptococci MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION (10)

  23. Reporting of Laboratory Data direct communication between laboratory and infection control personnel a weekly “work rounds”: discuss areas of mutual concern supplementary studies (molecular typing, environmental cultures, etc.) an early phone call MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION (11)

  24. Reporting of Laboratory Data an early phone call positive blood or normally sterile site cultures smears or cultures positive for acid-fast bacilli (AFB) isolation of Salmonella or Shigella isolation of MRSA, VRE, etc. detection of new or unusual pathogens (e.g., Legionella spp., vancomycin-resistant Gram-positive organisms) MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION(12)

  25. Reporting of Laboratory Data a computer database facilitating retrieval and analysis specimen type date of collection patient identification hospital number hospital service ward location organisms identified specialized testing antimicrobial susceptibility test results establishing a baseline for nosocomial infection rates MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION(13)

  26. Reporting of Laboratory Data Summary antibiogram frequency of isolation of nosocomial pathogens by anatomical site by hospital service empiric antimicrobial therapy MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION (14)

  27. Organism Storage isolates from normally sterile sites important antibiotic-resistant organisms from any site (MRSA, VRE, ESBL-producing Enterobacteriaceae) epidemiologically important pathogens (e.g., M. Tuberculosis) 3 to 5 years MICROBIOLOGY TESTING IN NOSOCOMIAL INFECTION (15)

  28. OUTBREAK RECOGNITION AND INVESTIGATION (1) infection control committee detects an outbreak of nosocomial infection define the extent of the outbreak learn the mode of transmission institute appropriate control measures clinical microbiology laboratory: support

  29. Communication infection control practitioners & Laboratory personnel outbreak types in the past laboratory resources required in the future extra costs OUTBREAK RECOGNITION AND INVESTIGATION (2)

  30. Problem 1: the number of cases necessary to constitute an outbreak organism patient population institution Problem 2: pseudo-outbreak misdiagnosis misinterpretation of epidemiologic data OUTBREAK RECOGNITION AND INVESTIGATION (3)

  31. Quality control problems contamination of strain preparation reagents false antimicrobial susceptibility test results culture specimen contamination Resolvent Care attention to quality control sterile technique construction controls OUTBREAK RECOGNITION AND INVESTIGATION (4)

  32. MOLECULAR TYPING IN THE OUTBREAKING SETTING (1) hospital epidemiology clinical setting species identification an epidemiologic link Antibiogram phenotypic typing methods AST biochemical profiles bacteriophage susceptibility patterns multilocus enzyme electrophoresis profiles

  33. epidemiologic objectives etermination of the source and extent the mode of transmission efficacy of preventative measures monitoring of infection in high risk areas genotypic typing methods MOLECULAR TYPING IN THE OUTBREAKING SETTING(2)

  34. MOLECULAR TYPING IN THE OUTBREAKING SETTING(3) genotypic typing methods Plasmid fingerprinting

  35. MOLECULAR TYPING IN THE OUTBREAKING SETTING(4) genotypic typing methods Restriction endonuclease analysis of chromosomal DNA with conventional electrophoresis

  36. MOLECULAR TYPING IN THE OUTBREAKING SETTING (5) genotypic typing methods Restriction-fragment length polymorphism (RFLP) analysis with nucleic acid probes

  37. MOLECULAR TYPING IN THE OUTBREAKING SETTING(6) genotypic typing methods Pulsed-field gel electrophoresis

  38. MOLECULAR TYPING IN THE OUTBREAKING SETTING(7) genotypic typing methods Polymerase chain reaction (e.g., RAPD, rep-PCR, CFLP, AFLP)

  39. CULTRUES OF HOSPITAL PERSONNEL AND ENVIRONMENT (1) Only when involvement in transmission of a nosocomail pathogen. • Blood products • Parenteral fluids and intravenous devices • Environmental surfaces • Tubes and containers • Disinfectants and Antiseptics • Respiratory therapy equipment • Air • Water and ice • Hands of personnel • Anterior nares of personnel

  40. hand of healthcare workers an important vehicle for transmission confirming the mechanism of cross-infection Culture method: broth-bag technique anterior nares usual reservoir for S. aureus (including MRSA) colonization CULTRUES OF HOSPITAL PERSONNEL AND ENVIRONMENT (2)

  41. Result interpretation finding the outbreak strain does not establish the direction of transmission or definitively implicate the health care worker as the source or reservoir for the outbreak Indiscriminate culturing confusing results ill will toward the infection control program CULTRUES OF HOSPITAL PERSONNEL AND ENVIRONMENT(3)

  42. routine monitoring sterilization infant formula other hospital-prepared products blood components prepared in an “open” system hemodialysis fluid disinfected equipment Others should not be performed. CULTRUES OF HOSPITAL PERSONNEL AND ENVIRONMENT (4)

  43. CONCLUSION Clinical microbiology laboratory --an essential component Ongoing cooperation and collaboration between the laboratory and the infection–control personnel Appropriate application of the newer methods for detection, identification, and typing of nosocomial pathogens

  44. Thanks!

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