Research article: Phenotypic Detection and Antimicrobial Profile of Metallo-Beta-Lactamase Producing Pseudomonas aeruginosa from Gunshot Wounds of In-Patients in Tertiary Hospitals in Maiduguri, Nigeria


Tijani Isa, Ibrahim Yusuf Ngoshe, Khadija Abdulkarim Ma’aji, Amnon Jonathan, Adam Mustapha



Background: Pseudomonas aeruginosa (P. aeruginosa) is the most common and significantly drug resistant bacteria isolated from all categories of in-patient wounds. The resistance is attributed to the production of metallo-β-lactamases (MβLs) responsible for high morbidity and mortality.

Methods: P. aeruginosa was isolated and identified from wound samples using Bergey’s manual of systemic bacteriology. Each wound swab was used to inoculate MacConkey agar and Cetrimide agar. The ethylenediaminetetraacetic acid (EDTA) disk testing method and modified Kirby-Bauer disc diffusion method was conducted to determine the phenotypic characterization and antimicrobial profile of MβL-producing P. aeruginosa.

Results: Out of the 100 wound swabs examined, 24 (24.0%) of the isolates were identified as P. aeruginosa. Among the 24 isolates identified as P. aeruginosa, 8/24 (33.3%) of those isolates were MβL-producing. Male in-patients had a higher prevalence of 19 (79.2%) for P. aeruginosa than females with 5 (20.8%) (P< 0.05). MβL-producing P. aeruginosa was of a higher prevalence in males with 7 (87.5%) than in females with 1 (12.5%) (P<0.05). Based on wound location, the lower limbs had a higher prevalence of 18 (75%) than those on the upper limbs 3 (12.5%), head 2 (8.3%) and abdomen 1 (4.2%) (P<0.05) for P. aeruginosa. MβL-producing P. aeruginosa also had higher prevalence for wounds on the lower limbs 7 (87.5%) compared with those on the upper limb 1 (12.5%), head and abdomen each with 0(0%) (P<0.05). Antimicrobial profiles of P. aeruginosa isolates indicated a 100% resistance against cefepime 30 µg and ceftazidime 30 µg and highest level of susceptibility (20.8%) for meropenem 10 µg, imipenem 10 µg and gentamicin 10 µg. While all the MβL-producing P. aeruginosa isolates recorded a 100% resistance against all the antibiotics used.

Conclusion and Recommendation: These results demonstrate that spread as well as the rate of drug resistance among the MβL-producing P. aeruginosa is concerning. Imipenem and meropenem are potential drugs of choice for treatment of infections caused by MβL-producing P. aeruginosa.


Key words: Metallo-Beta-Lactamases, Pseudomonas aeruginosa, Gunshot-wounds, In-patients, Antibiotic resistance, Maiduguri-Nigeria


Int. J. Bio. Lab. Sci 2023(12)1:31-39 【PDF】