Changing antimicrobial resistance pattern of isolates from an ICU over a 2 year period.

OBJECTIVE: To study the changing patterns of antimicrobial resistance in gram negative bacilli esp. E. coli, Klebsiella Pneumoniae, Pseudomonas and Staphylococcus aureus isolates from a 37 bedded ICU of a private hospital.
METHODS: All isolates obtained from a wide range of clinical samples (e.g.: urine, pus, blood, sputum, BAL, tracheal secretions) from ICU patients were evaluated for sensitivity patterns by Kirby-Bauer disc diffusion method.
RESULTS: In the 2 year study period the rise in the number of gram negative isolates was proportionally high along with increase in their resistance pattern. Dramatic rise in ESBL's has led to multidrug resistant E. coli and Klebsiella pneumoniae. Also organisms like Acinetobacter spp. and Pseudomonas aeruginosa are multiresistant making optimal therapy selection difficult. The incidence of ESBL's has increased from 30-75% of the total isolates. The sensitivity of Pseudomonas aeruginosa to Meropenem has decreased from 90% to 60%.The antibiotic that remained most active against all gram negative organisms for 2 years was Imepenem, Piperacillin-Tazobactum and Amikacin. The positive result from this study was decrease in the number of S. aureus isolates from 25% in 2008 to 12% in 2009. The reason for this achievement was implementation of good and strict infection control practices.
CONCLUSION: 1) Antibiotic resistance continues to rise among hospital acquired gram negative pathogens and complicates empirical selection of antibiotics in the ICU. 2) Klebsiella pneumoniae and Pseudomonas are still the dominant organisms in the ICU. 3) Imepenem, Piperacillin-Tazobactum and Amikacin are still highly active against Enterobacteriacea. 4) Local data and strict infection control practices can only control the spread of virulent and resistant organisms.