MICROBIOLOGICAL ORGANISMS AND THEIR ANTIMICROBIAL SENSITIVITY CAUSING VENTILATOR ASSOCIATED PNEUMONIA (VAP)

Antimicrobial Sensitivity Causing Ventilator Associated Pneumonia

Abstract

Objective: To determine the frequency of different causative bacteriological organisms and their antibiotic
sensitivity from Endotracheal Aspirate (EA) of patients suffering from Ventilator Associated Pneumonia (VAP).
Study Design: Prospective cross sectional study.
Place and Duration of Study: Intensive Care Unit (ICU), Combined Military Hospital (CMH) Lahore, from May
2013 to Nov 2013.
Material and Methods: A total of 180 cases of VAP, fulfilling the ınclusion criteria and admitted in the ICU, were
included in the study using the non-probability consective sampling technique. A written informed consent was
obtained from the family. All these patients underwent endotracheal aspirate for microscopy and culture.
Antibiotic sensitivity was determined using standard antibiotics regimens.
Results: Out of 180 patients, 165 (91.7%) were culture positive while 15  (8.3%) were culture negative. Gramnegative
bacilli accounted for about 70% of all isolates. The most common organism isolated was Pseudomonas
aeruginosa 25% (n=45) followed by MRSA 18.9% (n=34), Klebsiella 15.6% (n=28), Actinobacter spp 13.3% (n=24),
E.coli 11.7% (n=21) and Citrobacter spp 4.4% (n=8). Carbapenem was the most sensitive drug that was seen in our
setup but still 43.9% of the isolates showed resistance against it and resistance was noted still higher with
Actinobacter spp, where 83% isolates were resistant. Quinolones showed resistance in 100% of the isolates of
Actinobacter, MRSA and Citrobacter. While more than 50% strains of Pseudomonas, E.coli and Klebsiella were also
resistant to quinolones. Cephalosporins showed excellent sensitivity towards gram negative bacteria which
included Citrobacter (100% sensitive) and E.coli (80% sensitive). Polymxins showed more than 50% sensitivity to
Pseudomonas aeruginosa, Actinobacter, E. coli and Klebsiella.
Conclusion: VAP remains a very important hospital-acquired infection. The most prevalent etiological organism
in our study was Pseudomonas aeruginosa and the most effective antibiotics were carbapenems.