MICROBIOLOGICAL EPIDEMIOLOGY OF RESPIRATORY SPECIMENS IN ICU PATIENTS Dr Farooq Cheema, Dr Waseem Tariq, Dr Raja Ishtiaq, Dr Tabassum Qureshi, Dr Vincent Ioos, Dr Rubina Aman. Medical ICU, Pakistan Intsitute of Medical Sciences, Islamabad

VENTILATOR ASSOCIATED PNEUMONIA Ventilator Associated Pneumonia (VAP) is defined as a bacterial nosocomial pneumonia occurring more than 48 hours after endotracheal intubation in patients placed on mechanical ventilation. VAP is the most prevalent infection in ICU patients, accounting for up to 46% of nosocomial infections 1. VAP causes a significant increase in mortality, morbidity and length of stay amongst ICU patients. Early institution of empirical antibiotic therapy with appropriate drugs leads to a decrease in the mortality attributable to VAP. 1. Vincent JL, Bihari DJ, Suter PM, et al.: Prevalence of Nosocomial Infections in ICU’s in Europe. Results of the European Prevalence of Infection in Intensive Care (EPIC) Study, JAMA 1995, 274:

ORGANISMS RESPONSIBLE FOR VAP The major pathogens responsible for causing VAP are Gram Negative Bacteria and Staph. Aureus. However, there is often a big difference in the causative organisms for VAP even from one hospital to another due to the varying microbiological environment. There is also a dearth of data regarding the microbiological epidemiology of VAP in developing countries.

VAP: PATHOGENS IN DEVELOPING COUNTRIES

VAP: PATHOGENS IN DEVELOPED COUNTRIES

AIMS AND OBJECTIVES Description of the epidemiology of the pathogens found in the tracheal secretions of mechanically ventilated patients in the Medical ICU at PIMS. Basis for editing recommendations for the empirical treatment of VAP in our institution –Improving outcome –Decreasing emergence of resistant bugs

STUDY DESIGN This is a retrospective analysis of data collected from the PIMS Laboratory Management Information System (LMIS). We analyzed the results of tracheal secretions c-s study done for patients admitted in the Medical ICU and placed on mechanical ventilation from 01/01/2007 to 31/12/2007. Data regarding the severity of illness, mortality and length of mechanical ventilation was collected from an Excel® file maintained prospectively in the ICU.

MATERIALS AND METHODS A total of 182 samples from 96 patients were retrieved, in which 242 bacteria were cultured. 24 samples showed no growth, 1 sample showed a mixed growth. Bacteria which were cultured twice from the same patient within 7 days were excluded from the analysis to prevent duplication of results. Tracheal Secretions C-S studies are usually done in the ICU only if there is a clinical suspicion of an infection e.g. fever, new infiltrates on a chest x-ray, worsening ABGs, elevated WBC counts, new onset of purulent secretions.

POPULATION STUDIED Pop: 96 patients (2007 MICU 358 with 77% on MV) Mean age: 38 years (2007 MICU 39) Sex ratio (M/W): 1,52 (2007 MICU 1,8) 81% medical, 19% surgical (2007 MICU 74% M) Mean SAPS3: 63 (2007 MICU 65) Expected mortality: 41,8% Observed mortality: 44,5% SMR=1,06 (2007 MICU 1,18) Mean length of stay: 17 days (2007 MICU 9 days) Mean length of mechanical ventilation: 13 days (2007 MICU 7 days)

RESULTS Bacteria CulturedPercentage Pseudomonas5628.3% Klebsiella pneumoniae % Escherichia coli2010.1% Proteus2613.1% Citrobacter spp.10.51% Serratia liquefaciens10.51% Acinetobacter3216.2% Staph. Aureus (MSSA)73.53% Staph. Aureus (MRSA)136.55% Coagulase neg. Staph.10.51%

RESULTS

PSEUDOMONAS SENSITIVITY TO ANTI-PSEUDOMONAL PENICILLINS

PSEUDOMONAS SENSITIVITY TO CEPHALOSPORINS

PSEUDOMONAS SENSITIVITY TO QUINOLONES

PSEUDOMONAS SENSITIVITY AMINOGLYCOSIDES

PSEUDOMONAS SENSITIVITY TO CARBAPENAMS

ENTEROBACTERIACEAE SENSITIVITY TO PENICILLINS

ENTEROBACTERIACEAE SENSITIVITY TO CEPHALOSPORINS

ENTEROBACTERIACEAE SENSITIVITY TO QUINOLONES

ENTEROBACTERIACEAE: SENSITIVITY TO AMINOGLYCOSIDES

ENTEROBACTERIACEAE SENSITIVITY TO CARBAPENAMS

ACINETOBACTER SENSITIVITY TO PENICILLINS

ACINETOBACTER SENSITIVITY TO CEPHALOSPORINS

ACINETOBACTER SENSITIVITY TO QUINOLONES

ACINETOBACTER SENSITIVITY TO AMINOGLYCOSIDES

ACINETOBACTER SENSITIVITY TO CARBAPENAMS

MRSA SENSITIVITY TO VARIOUS ANTIBIOTICS

LIMITATIONS Retrospective analysis, colonization versus infection not assessed. Low specificity of tracheal secretions C-S in the diagnosis of VAP. Lack of standardization of the culture and sensitivity study.

DISCUSSION Epidemiology of respiratory specimen is dominated by gram negative bacteria and pseudomonas as the first pathogen High incidence of the resistance to ceftazidime, imipenem, amynoglycoside and quinolones Low incidence of staphylococcus aureus isolates and among them one third are methicillin sensitive

CONCLUSION Recommendations for empirical treatment of VAP in our MICU: should target pseudomonas (piperacillin +tazobactam or cefoperazone + sulbactam) + (amikacine or tobramycine) MRSA should be considered only when the patient is very severe or is known to be colonized by MRSA Prospective surveillance of VAP: –on the basis of internationally recognized definition –correlated with the number of days of mechanical ventilation –To calculate an incidence Interventions to reduce VAP

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ENTEROBACTERIACEAE SENSITIVITY TO PENICILLINS

ENTEROBACTERIACEAE SENSITIVITY TO CEPHALOSPORINS

ENTEROBACTERIACEAE SENSITIVITY TO QUINOLONES

ENTEROBACTERIACEAE: SENSITIVITY TO AMINOGLYCOSIDES

ENTEROBACTERIACEAE SENSITIVITY TO CARBAPENAMS