Klebsiella pneumoniae respiratory isolates from 2000 to 2004 in a Malaysian hospital: characteristics and relation to hospital antibiotics consumption.

INTRODUCTION: Klebsiella pneumoniae ranks high as a cause of community-acquired pneumonia in hospitalised patients in Malaysia. METHODS: A retrospective study of 5,990 clinical respiratory specimens in patients, with a mean age of 54 (standard deviation 18.5) years, admitted to an urban-based general hospital between 2000 and 2004, was conducted. RESULTS: The percentages of K. pneumoniae isolates during these years were 11, 19.1, 41.4, 27.8 and 16.6 percent, respectively. During this time, the percentage of isolates resistant to ampicillin were consistently in excess of 80 percent, those resistant to cephalosporins were relatively stable between eight and 23 percent, while those resistant to beta-lactam/beta-lactamase inhibitors [amoxicillin clavulanic acid/ ampicillin-sulbactam] and aminoglycosides steadily increased between six and 58 percent. Compared with hospital consumption of these corresponding antibiotic classes, only beta-lactam/beta-lactamase inhibitors and aminoglycosides showed a clear trend of eight- and four-fold increases, respectively. Co-resistance rates in isolates resistant to ampicillin and amoxicillin-clavulanic acid/ampicillin-sulbactam were generally low to second to third generation cephalosporins (less than 20 percent). CONCLUSION: Our local findings highlighted the changing trend in respiratory K. pneumoniae over a five-year period, and its escalating resistance to beta-lactam/beta-lactamase inhibitors and aminoglycosides that is possibly attributable to the widespread use of these antibiotics in our hospital.