Hospital Acquired Infections. Anucha Apisarnthanarak, MD Infectious Disease Division Thammasart University Hospital

Transcription

1 Hospital Acquired Infections Anucha Apisarnthanarak, MD Infectious Disease Division Thammasart University Hospital

2 Nosocomial Infections (NI) Infections acquired in the hospital May become apparent in hospital or after discharge 2 million people per year affected 5% of all hospitalized patients Direct costs over 5-10 billion $ per year

3 Nosocomial Infections Characteristics Most are endemic rather than epidemic Source may be endogenous or exogenous 30-50% may be preventable

4 Risk Factors for Noso Infections Age Surgery Immunosuppression Length of hospitalization Severity of illness Previous infection Invasive procedures

5 Endemic vs Epidemic NI Endemic UTI (38%) SSI (27%) Pneumonia (16%) E. coli (19%) Enterococcus (10%) Staph. aureus (10%) Epidemic UTI (10%) SSI (9%) Pneumonia (12%) Enteritis (17%) Hepatitis (12%) E. coli, ENTS <1% S. aureus (12%) Serratia (8%) HBV (10%)

6 What is the most common nosocomial infection? A) UTI B) BSI C) SSI D) VAP E) Infections in other organ systems

7 Sites of Noso Infections Urinary tract: UTI (42%) Surgical site (incision): SSI (24%) Pneumonia (11%) Bacteremia (5%) Other sites (18%)

8 Nosocomial UTIs The most common NI 1% complicated by bacteremia Common pathogens- gram (-) rods Enterococci 75-85% related to urinary catheterization Cumulative daily risk 5-10% / day

9 Which practice should be discourage? A) Start Ampho B bladder irrigation in patient with evidence of candiduria, but without Foley s cath B) Hand washing everytime, when perform any procedure C) Try to discontinue Foley s catheter for every patient D) Apply universal precuation in every patient E) All are correct

10 Prevention of Noso UTIs Avoid catheters, Remove ASAP Insert by trained personnel Do not break system Bag off floor, Secure to thigh, Downhill flow Wash hands between pt. care activities Ag+ /Nitrofurantoin coated devices

11 How many percent will SSI occur in patients underwent emergency surgery for bowel perforation? A) 1.5 % B) 10 % C) 15 % D) 25 % E) 30 %

12 Types of Surgical Site & Risk Clean 1.5% Clean contaminated 8-11% Contaminated % Dirty & Infected >27% NNIS Risk Index = stratifies by procedure based on length of surgery, severity of illness

13 Determinants of SSI Microbial contamination antibiotic prophylaxis, prep, razor shave, wound care Surgical technique tissue damage, hematoma, closure, duration Host conditions age, obesity, vascular disease, diabetes (esp. poor control), infection at a distant site (e.g., UTI)

14 Nosocomial Pneumonia More than 300,000 / year Highest mortality rate of nosocomial infections Estimated 17,500 deaths / year Higher incidence in surgical and ICU patients Risk factors =Intubation, ventilator duration

15 Etiology of Nosocomial Pneumonia Pseudomonas aeruginosa (16.9%) Staphylococcus aureus (12.9%) Klebsiella sp. (11.6%) Enterobacter sp. (9.4%) E. coli (6.4%) Serratia sp.(5.8%) Other (37%)

16 What is not a modificable risk factors for VAP? A) Elevate head of bed B) Good hand washing C) Pulmonary toilet D) Avoid H2 blocker E) Use selective gut decontamination

17 Nosocomial Pneumonia Prevention: elevate head of bed - anti-aspiration measures good pulmonary toilet good infection control Avoid H2 blockers Selective gut decontamination not beneficial

18 Risk Factors for Nosocomial Pneumonia Age Antibiotics, colonization Aspiration, mental status changes Surgery, length of stay, SOI, Immunosuppression, obesity, pulm disease Intubation, ventilator, vent days Viral infections, bacteremia

19 Fatality Rates Noso Pneumonia Pseudomonas sp. (72%) Klebsiella, Enterobacter sp, Serratia (40%) E. coli (31%) Staphylococci (35%) Others (35%)

20 Legionella Seasonal & Geographic differences Epidemic and Endemic Potable water, heat exchange apparatus Large buildings Susceptible hosts: immunosuppressed, elderly, lung disease, smokers, renal failure, diabetes

21 Nosocomial Bacteremia Increasing in frequency IV catheters risk at insertion & with increased duration Common pathogens S. epidermidis, S. aureus, Enterococci, gram (-) rods, & Candida sp.

22 What is the most common sites of bacteremia from CVC? A) Contaminated infusated B) Contaminated hub C) Skin flora near the site of infection D) Contaminated device before insertion E) All are correct

23 Sources of Catheter-associated Bacteremia CONTAMINATION OF DEVICE PRIOR TO INSERTION Extrinsic >>Manufacturer SKIN ORGANISMS Endogenous Flora HCW hands Contam Disinfectant Invading Wound CONTAMINATION OF CATHETER HUB Extrinsic (HCW) Endogenous (Skin) CONTAMINATED INFUSATE Fluid Medication Extrinsic Manufacturer Vein Skin Fibrin Sheath, Thrombus HEMATOGENOUS From Distant Local Infection

24 Bacteremia Associated with Contaminated Infusions Usually in epidemics Characteristic pathogens: Pseudomonas cepacia, Enterobacteragglomerans, E. cloacae, Flavobacterium May affect patients who lack traditional risk factors for line related infections

25 Prevention of IV Related Bacteremia Sterile, aseptic technique, barrier precautions for insertion Chlorhexidine, dressing changes, line care Remove as soon as possible Change peripheral catheters every 72 hours No routine changes of central catheters Ag+\ chlorhexidine, Rifampin\minocycline coated catheters

26 Which pathogens could be transmitted via blood borne route? A) Syphilis B) Hepatitis C C) Malaria D) West Nile E) CMV F) All can be transmitted via blood borne route

27 Infections Related to Blood Transfusions Hepatitis B Hepatitis C Non A, B, C hepatitis HIV CMV Malaria, Babesiois, Q Fever, Syphilis West Nile virus

28 Infections Related to Contaminated Equipment Respiratory Therapy Equipment (Pneumonia) Bronchoscopes/ Endoscopes (Mycobacteria, Salmonella, Pseudomonas) Syringes (Mycobacteria, HBV, HIV) Whirlpools (Legionella, Pseudomonas) Dialysis (Mycobacteria, gram (-) rods)

29 Environmental/Material Contamination Construction (Aspergillus, Legionella, sugical wounds) Water (Legionella, Mycobacteria) Bone wax (Mycobacteria) Elastoplast (Rhizopus)

30 Pediatric Nosocomial Infections S. aureus, S. epidermidis, Pseudomonas, other gram (-) rods Candida Rotavirus, RSV, Influenza Varicella Bordetella pertussis

31 Example of a Pediatric NI: RSV Respiratory syncytial virus (RSV) Seasonal: winter & early spring Stable on solid surfaces for ~6-24hrs Transmission via healthcare workers hands Pneumonia, apnea prematurity, immunosuppressed, cardiopulmonary disease Prevention gloves & gloves, cohorting

32 Highly Contagious Nosocomial Infections Influenza Rubella, Measles Varicella RSV Rotavirus Pertussis Ebola /Viral Hemorrhagic fevers

33 Setting for Nosocomial Infections Susceptible host: debilitated, devices, surgery, antibiotics Unusual Exposure: many people, close proximity hospital flora unique modes of transmission

34 Control of Nosocomial Infections Infection control practitioners Physicians Organized surveillance and control activities System to report surgical wound infection rates to surgeons HANDWASHING & YOU

35 What are not antibiotic resistant bacteria that warrant contact isolation? A) MRSA B) MDR-gram negative C) Imipenem resistant Gm-negative microorganisms D) ESBL E) Tuberculosis

36 Antibiotic Resistant Bacteria Methicillin resistant S. aureus (MRSA, ORSA) Vancomycin resistant S. aureus (VRSA) Vancomycin resistant enterococci (VRE) Inducible beta lactamases (Enterobacter, Serratia, Acinetobacter, Citrobacter) Pseudomonas sp., Klebsiella sp.

37 Antimicrobial Resistance among Pathogens Causing Nosocomial Infections Methicillin (oxacillin)-resistant Staphylococcus aureus Percent Resistance Non-Intensive Care Unit Patients Intensive Care Unit Patients Percent Resistance Vancomycin-resistant enterococci Source: National Nosocomial Infections Surveillance (NNIS) System

38 Antimicrobial Resistance among Pathogens Causing Nosocomial Infections 3 rd generation cephalosporinresistant Klebsiella pneumoniae Fluoroquinolone-resistant Pseudomonas aeruginosa Percent Resistance Percent Resistance Non-Intensive Care Unit Patients Intensive Care Unit Patients Source: National Nosocomial Infections Surveillance (NNIS) System

39 Antibiotic Resistant Bacteria: Risk Factors Severity of illness Chronic hemodialysis Oncology, BMT, organ transplantation Recent nursing home or hospital stay Prolonged hospitalization Invasive devices (catheters) Prior antibiotic use

40 Antibiotic resistance in S. aureus 1943 Introduction of penicillin 1945 S. aureus penicillinase reported 1961 Methicillin introduced 1963 Methicillin resistance reported 1975 NNIS rate of MRSA = 2.4% 1991 NNIS rate of MRSA = 29% 1999 NNIS rate of MRSA = 50% 2002 Vancomycin resistance reported in US

41 Trends of prevalence rates for penicillinase-producing S. aureus in hospitals and the community Year Hospital Community 1940 % Resistant

42 MRSA - Sites of colonization Nares Perineum Groin & axillae Throat Non-intact skin (decubital ulcers, eczema, psoriasis, surgical site, burns)

43 MRSA- Nosocomial Transmission Case reports of MRSA outbreaks from the 1980 s & early 1990 s - rapid spread VA NH - asymptomatic MRSA carrier resulted in 39/114 (34%) pt colonization w/ the MRSA within 15 mos. UVA - index case of MRSA resulted in 22 cases within 6 mos.; in 14 mos % all S. aureus nosocomial infection were MRSA Strausbaugh et al, ICHE, 1991 Peacock et al, Ann Int Med, 1980

44 Nosocomial transmission of MRSA Healthcare workers hands- primary mode of transmission MRSA transiently carried on hands recovered from re-used gloves Environmental (?) environmental samples in MRSA(+) pt rooms 85% of urine and wound (+) pts had (+) environmental cx vs 36% of others 65% of RN uniforms or gowns (+)MRSA Boyce et al. ICHE, 1997

45 Vancomycin-Resistant S. aureus (VRSA) Michigan July 2002 Diabetic on chronic dialysis Chronic vancomycin rx for foot ulcer VRSA isolated from catheter tip; VRSA, VRE, & K. oxytoca from foot ulcer Pennsylvania Sept 2002 Chronic foot ulcer VRSA isolated unrelated to Michigan case Limited treatment options (IV antibiotics, expensive) MMWR, 2002;51(26); MMWR, 2002 / 51(40);902

46 Preventing the Spread of Antibiotic Resistance WASH YOUR HANDS! Limit antibiotic use Treat true infections, not colonization Use narrow-spectrum antibiotics when possible Remove invasive devices ASAP Stop treatment when infection is cured No abx use for viral syndromes (e.g., URI) Isolate pts known to carry resistant bacteria

47 Infection Control : Isolation Systems Standard Precautions Category Specific contact, respiratory, blood and body fluid Disease Specific measles, TB, varicella, MRSA

48 Standard Precautions All body substances considered infectious Barrier precautions for activity based on risk of exposure to body fluids Avoid sharps injuries, exposures Avoid contact w/ mucosa & non-intact skin

49 Contact Precautions Infection or colonization with highly contagious or multiply-resistant pathogens VRE, MRSA, C. difficile, impetigo etc. Gowns & gloves to enter room, NO EXCEPTIONS! Dedicated equipment Remove gowns, gloves, wash hands before leaving room

50 Droplet Precautions Meningococcus, influenza, pertussis, mumps Single room No special air handling system Surgical mask wore by all entering room Avoid transport out of room; patient to wear surgical mask

51 Airborne (AFB) Precautions Use negative pressure Keep doors closed Use N95 respirator (not surgical mask) Limit visitors, avoid transport Patient to wear surgical mask (NOT N95) & cover mouth for coughing

52 Chicken Pox, Measles Use negative pressure Keep door closed Non-immune persons should not enter room If patient transport essential, patient wears surgical mask and cover all lesions

53 General Recommendations Standard precautions always applies Do not DC isolation without consulting IC WASH hands or disinfect frequently Minimize transport of isolated patients Notify receiving departments of isolation