Spectrum and antimicrobial susceptibility of bacterial organisms isolated from patients in a bone marrow transplant centre-A review of 6 years

ABSTRACT

To determine the spectrum and antimicrobial susceptibility pattern of pathogens isolated from bone marrow transplant centre and to examine the evolution of bacterial resistance to antibiotics in these patients. It was a retrospective study conducted in the department of Microbiology, Armed Forces institute of Pathology [AFIP] from January 2004 to December 2009. Isolation, identification and antimicrobial susceptibilities were performed by standard methods. Gram negative bacterie accounted for 50.4% of the total isolates and Gram positives 49.6%. Escherichia coli was the most common isolate among the gram negative rods followed by Pseudomonas spp and Acinetobacter spp. Amongst the Gram positive organisms staphylococcus aureus and coagulase negative staphylococci followed by enterococci were the predominant organisms. The susceptibility of methicillin resistant staphylococcus aureus remained 100% for Vancomycin and Linezolid, while those of minocycline, fusidic acid and doxycycline were at an acceptable level of above 60%. Imipenem remained the most effective antibiotic for Gram negative rods. Acinetobacter spp. was the most problematic organism as only 62% isolates were susceptible to imipenem. Linezolid, vancomycin and tigecycline were very effective for enterococci. Ciprofloxacin sensitivity has been reduced among most of the bacteria isolated. The spectrum of isolates from neutropenic patients in our population appears to be changing with a shift towards Gram-positive microorganisms. At the same time resistance to most of the commonly used antimicrobials is increasing. Continuous surveillance of their susceptibility patterns is essential for formulation of empiric therapeutic regimens for these patients