Changing Antimicrobial Resistance Pattern of Isolates from an ICU Over a 3 Year period.

OBJECTIVE: To study the changing patterns of antimicrobial resistance in gram negative bacilli esp. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa species and Gram positive Staphylococcus aureus isolates from a 37 bedded ICU of a private hospital. METHODS: Antibiotic susceptibilities were determined by using disk diffusion and Vitek-2 system. RESULTS: A total of 13410 clinical samples were screened over a period of 3 years, among which 16.77 percent (2250 isolates) were culture positive. In recent years there has been an increased incidence of extended-spectrum ß- lactamase (ESBL). The ESBL producing Escherichia coli and Klebsiella pneumonia has shown an increase in resistance to the tune of 80-90% from 2011 to 2013. The prevalence of resistant strains of Acinetobacter species and Pseudomonas aeruginosa has shown an increase in Imipenem and Meropenem resistance at the rate of 75-80%. CONCLUSIONS: Antibiotic resistance has shown an increase in gram negative pathogens and thereby has created a significant problem in choosing the right antibiotic for empirical usage. Rise in resistance has left little choice for the clinicians to select antibiotics. Klebsiella pneumonia ESBL and Escherichia coli ESBL have become dominant organisms in the ICU. Piperacillin + Tazobactum, Imipenem and Amikacin have decreased sensitivity against Enterobacter. A number of old antibiotic compounds such as Polymyxins, Fosfomycin, and Aminoglycosides are re-emerging as valuable alternatives for the treatment of ESBL producing bacteria. Cases of MDR Escherichia coli and Klebsiella pneumonia bacteria have increased in recent years and are now the most frequent cause of hospital acquired infections.

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.