Microbiological and Minimum Inhibitory Concentration Study of Ventilator-associated Pneumonia Agents in Two University-associated Hospital Intensive Care Units in Mazandaran

Abstract

Objectives: This study aimed to determine the antimicrobial susceptibility pattern of microorganisms causing VAP in the intensive care units (ICU) of two university associated hospitals in the province of Mazandaran in Iran from 2008 to 2010. Materials and Methods: This study was performed on VAP patients diagnosed with the clinical pulmonary infection score (CPIS) in ICU’s of two university hospitals. For each patient suspected of VAP, quantitative culture of endotracheal aspiration (QEA) was performed and minimum inhibitory concentration (MIC) was determined by a micro dilution test. Data was analyzed by the SPSS 17 software and a P < 0.05 was considered to be statistically significant. Results: In this study, the type and the frequency of the microbial agents causing VAP was as follows: coagulate negative staphylococci (23.3%), Escherichia coli (E. coli) (21.7%), Staphylococcus aureus (S. aureus) (18.3%), Pseudomonas aeruginosa (P. aeroginosa) (18.3%), Enterobacter spp (11.7%). and Klebsiella pneumoniae (K. pneumonia) (6.7%). 35.71% of coagulate negative staphylococci were sensitive to vancomycin. All of the isolated E. coli was resistant to ceftazidime, but 50% sensitive to gentamicin and meropenem. 54.54% of isolated S. aureus were resistant to vancomycin. All of the isolated P. aeroginosa cases were sensitive to imipenem while 50% were resistant to ceftazidime. Conclusions: In patients with VAP, carbapenems had good activity against P. aeroginosa. Increasing resistance of S. aureus to vancomycin requires more attention and further studies.