Purpose: Bloodstream infection remains a major cause of morbidity and mortality in patients undergoing treatment for cancer. Severe infections due to
Gram-negative bacilli & staphylococci are common in cancer patients. Altered gut flora because of frequent antibiotic administration and damage of epithelial surfaces
contribute to the development of infection. To access the use of new potent antibiotics against bloodstream infection in cancer patients and to determine the cross resistance
of Gram-negative bacterial strains.
Materials and Methods: We studied the bacterial spectrum & antimicrobial susceptibility pattern of cephalosporins,
fluoroquinolones, carbapenems and aminoglycosides against Gram-negative bacterial strains in cancer patients. The susceptibility was determined by broth dilution method
according to National Committee for Clinical Laboratory Standards (NCCLS) now called Clinical Laboratory Standards Institute (CLSI) during study period (July 2006 to Jan 2007).
Results: A total of 60 Gram-negative bacterial blood cultures were examined. Among these,
Pseudomonas aeruginosa
was the most common (38%). The Minimum Inhibitory Concentration at which 50% (MIC
50 ) and 90% (MIC
90 ) of
Enterobacteriaceae
and
P. aeruginosa inhibited were found. Resistance in
P.aeruginosa against cefepime, meropenem, ciprofloxacin, ceftriaxone, tobramycin, cefoperazone and imipenem
was 60%, 13%, 80%, 67%, 40%, 90% and 10% respectively while for
Enterobacteriaceae 80%, 20%, 88%,
72%, 20%, 90% and four per cent resistance was observed. Meropenem was found to be the most effective antimicrobial against Gram-negative bacteria.
Conclusion: High resistance observed in this study warrants the needs of surveillance of resistant pattern of antimicrobial agents. Due to increased level of drug
resistance, carbapenem would be a prudent choice in high- risk cases.