Antimicrobial resistance profiles of and associated risk factors for Pseudomonas aeruginosa nosocomial infection among patients at two tertiary healthcare facilities in Lusaka and Copperbelt Provinces, Zambia.

Background: Antimicrobial resistance (AMR) of pathogens such as Pseudomonas aeruginosa is among the top 10 threats to global health. However, clinical and molecular data are scarce in Zambia. We, therefore, evaluated the AMR profiles of P. aeruginosa nosocomial infections (NIs).

Methods: A year-long hospital-based cross-sectional study was conducted at two large tertiary-level hospitals in Zambia. Patients with current or previous hospital contact were screened for NIs. The current study focused on patients diagnosed with P. aeruginosa NIs. Clinical specimens were collected for bacteriological culture, and PCR amplification of 16S rRNA gene fragments was performed on pure isolates. Hospital or NIs were defined as infections that arise during hospitalization, occurring at least 48 h after admission. The Kirby-Bauer's disk diffusion method was used to evaluate antibiotic resistance patterns. The association between AMR and risk factors was analysed using the χ² test.

Results: Eight hundred and forty-one patients were screened, and clinical specimens were collected and analysed. Of them, 116 (13.7%) were diagnosed with P. aeruginosa NIs. The participants' ages ranged from 15 to 98 years, with a mean of 51 (SD ± 18). Catheter-associated urinary tract infections (57%) were the most common, followed by pressure sores (38.7%). P. aeruginosa isolates were primarily susceptible to amikacin, which had the highest resistance to FEP. We observed a high prevalence of multidrug resistance (73.6%). The AMR was associated with carbapenem-hydrolysing β-lactamase gene blaOXA-51 and surgical care.

Conclusions: This study has demonstrated that multidrug-resistant P. aeruginosa is prevalent in hospitals in Zambia's Lusaka and Ndola districts and possibly countrywide.