Clinical and community strains of Klebsiella pneumoniae: multiple and increasing rates of antibiotic resistance in Abha, Saudi Arabia

Abstract

Klebsiella pneumoniae is the most commonly isolated bacterial species in a maternity hospital in Saudi Arabia. Here, 380 strains isolated in 1997 and 480 strains in 1999 were studied for their resistance antibiograms, using the standardised disc diffusion test. Of 16 antibiotics tested, four in 1997 and six in 1999 were ineffective against > 50% of the respective isolates, and resistance rates to 11 antibiotics increased over the two-year period (P = 0.05-< 0.0001). With resistance rates of < 20%, imipenem, ciprofloxacin, gentamicin and cefotaxime were more effective in 1997; only imipenem and ciprofloxacin remained as effective in 1999. In addition, 105 community strains were tested and > 50% were resistant to four antibiotics. Resistance rates to most antibiotics were lower than those of clinical strains (P = 0.0285-< 0.0001). Imipenem resistance was detected among both clinical and community isolates. Multiresistance was 64.5% in 1997 and 79.2% in 1999 (P < 0.0001), and 83.8% in community strains in 1999. Using the double-disc synergy test, extended-spectrum beta-lactamase (ESBL) was detected in 27.5% of ceftazidime-resistant clinical strains isolated in 1999. Among the clinical strains, seven (65%) and 11 (67.9%) resistance antibiograms occurred frequently in 1997 and 1999, respectively. Such frequency was not observed among community isolates. These findings confirm the alarmingly high rates of multiresistance and the emergence of ESBL-producing strains, highlighting the urgent need to restrict over-the-counter availability of antibiotics, and increase awareness in the local medical community.