Prevalence of Metallo-betalactamase Producing Pseudomonas aeruginosa in Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi

Pseudomonas aeruginosa is a common nosocomial pathogen that readily develops resistance to cephalosporins like Ceftazidime and beta-lactam antibiotics such as Imipenem through the production of Metallo-betalactamase (MBL). This study investigated the prevalence of MBL-producing P. aeruginosa at NAUTH, Nnewi. A total of 125 swab samples were collected from 44 ward door handles and 81 patient bedside handles. Samples were cultured on selective media to isolate P. aeruginosa, followed by standard identification using Gram staining and biochemical tests. Antibiotic sensitivity testing (AST) was performed, and Ceftazidimeresistant isolates were screened for MBL production using Imipenem alone, Imipenem with EDTA, and Imipenem with Dipicolinic acid. Contamination was highest on patient bedside handles (62.5%), followed by ward door handles (25%) and controls (12.5%); no isolates were found on laboratory door handles. The Male Surgical Ward (MSW) had the highest P. aeruginosa prevalence (57.14%), followed by the Children’s Ward (28.57%) and Female Surgical Ward (14.29%). MBL-producing strains were most prevalent in MSW (66.67%), followed by FSW (33.33%). No MBL-producing strains were found in the Children’s Ward. One ward door handle isolate (25%), two bedside isolates (50%), and one control (25%) tested positive for MBL production. Imipenem-EDTA showed the highest inhibition zone (29 mm), followed by Imipenem-Dipicolinic acid (28 mm), while Imipenem alone had the least (11 mm). Imipenem combined with EDTA was most effective against MBL-producing P. aeruginosa. Regular disinfection of high-touch surfaces in affected wards is strongly recommended.

Keywords: Handles, Pseudomonas aeruginosa, Metallo-beta lactamase, Imipenem, Imipenem with chelating agents (EDTA, Dipicolinic acid).