Epidemiological characteristics of Klebsiella ozaenae infection and its antibiotic susceptibility: Experience of a tertiary care hospital in the Eastern Province of Saudi Arabia

BACKGROUND:Klebsiellaozaenae (K. ozaenae), a forgotten pathogen that normally colonizes the upper respiratory mucosa, can be associated with severe and invasive infections. The objectives of this study were to determine the frequency of isolation of K. ozaenae at the microbiology laboratory in a tertiary hospital and the scope of diseases associated with it and to characterize its antimicrobial susceptibility pattern. MATERIALS AND METHODS:This cross-sectional study analyzed the retrospective data, from 2002 to 2021, on cases with laboratory-confirmed isolation of K. ozaenae at a tertiary care hospital. The primary outcome was to identify the scope of K. ozaenae infections and their antimicrobial susceptibility patterns. K. ozaenae isolation was done by cultivation on microbiological culture media, whereas its identification and antimicrobial susceptibility pattern were performed using either Microscan or Vitek automated systems. Data was gathered and analyzed in Excel. The percentage of resistance was calculated as the number of resistant isolates from the total isolates multiplied by 100. Similarly, the percentage of sensitivity was calculated as the number of sensitive isolates from total isolates multiplied by 100. RESULTS:K. ozaenae was detected in 59 cases during the study period. K. ozaenae was associated with urinary tract infections (39%), nasal infections (18.6%), other respiratory tract infections including sinusitis, bronchiectasis, and pneumonia (16.9%), and wound infections (15.3%). It was also associated with invasive infections such as bacteremia (3.4%) and abscesses (3.4%). K. ozaenae showed susceptibility to multiple antibiotic classes, but was resistant to ampicillin, piperacillin, nalidixic acid, and nitrofurantoin. K. ozaenae isolates from urinary tract infections had higher antibiotic resistance percentage than isolates from other infections, particularly to amoxicillin/clavulanic acid (P = 0.007, 95% confidence interval [CI]: 1.84-375), ciprofloxacin (P < 0.0001, 95% CI: 4.6-111.2), and trimethoprim/sulfamethoxazole (P < 0.001, 95% CI: 3.1-63.6). CONCLUSION:Our data show that K. ozaenae is a pathogen with a spectrum of diseases wider than expected and a unique antibiotic susceptibility pattern in urinary tract infections.