Antimicrobial resistance of 280 bacterial pathogens isolated from hematology unit

Objective All bacterial pathogens isolated from hematology unit during the period of January 2000 - June 2004 were analyzed to understand the distribution of infection site and pathogens, as well as the status of antimicrobial resistance for better empirical antibiotic therapy. Methods Bacterial susceptibility test was carried out using Kirby-Bauer disk method. Results were interpreted according to NCCLS standards. WHONET-4 software was used to analyze the susceptibility data. Results A total of 280 clinical isolates including 129 (46.1%) strains of gram-positive cocci, 149 (53.2%) strains of gram-negative bacilli and 2 (0.7%) gram-positive bacilli. The dominant source of pathogens was blood (115/280, 41.1%), followed by sputum (80/280, 28.6%). Coagulase negative Staphylococcus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus were the most frequently isolated pathogens. Oxacillin resistance was identified in 17.6% (3/17) of S. aureus and 69.9% (51/73) of coagulase negative Staphylococcus. About 35% (7/20) of Klebsiella spp. and 40.5% (17/42) of E. coli isolates produced extended-spectrum β-lactamases. Gram-negative bacilli were most susceptible to imipenem (91.1%), amikacin (89%), cefepime (84.1%), and cefoperazone-sulbactam (81.1%). Gram-positive cocci were most susceptible to vancomycin (100%) and teicoplanin (95.6%). Conclusions The most common site of infection is bloodstream and the dominant pathogen is conditional pathogen in hematology. Timely collection of specimens, better microbiological identification and appropriate susceptibility testing are essential for effective infection control and prevention of resistance.