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

ABSTRACT

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.