Faculty: Health Sciences And Technology
Department: Medical Laboratory Science


Ehiaghe, I. J.
Nwobu, R. A. U.


Postoperative surgical wound infection is a significant clinical challenge in hospitals in developing countries where proper healthcare delivery is hampered by limited resources. Currently there is paucity of documented information on the prevalence of multidrug resistant bacteria isolated from surgical wound infections at University of Benin Teaching Hospital (UBTH) and Nnamdi Azikiwe University Teaching Hospital (NAUTH). Availability of such information would assist in the development or the review of in –use antibiotic policy of the institution. This study investigate the phenotypic and molecular characterization of multidrug resistant bacteria isolates implicated in surgical wound infections among hospitalized patients at UBTH and NAUTH in order to generate findings which could drive reformation of policies in management of patients with surgical wound infections. This study was conducted to investigate the phenotypic and molecular characterization of bacteria recovered from 362 swabs specimens of patients with clinically diagnosed postoperative surgical wound infections from UBTH (Edo state) and NAUTH (Anambra state) within a period of one year. A cross sectional study using the randomized sampling method and specimens were cultured on Blood and MacConkey agar media and incubated aerobically and anaerobically for 48 hours. Antibiotic susceptibility of isolates was determined by Kirby-Bauer disk diffusion technique on Mueller-Hinton agar. Plasmid DNA profiling were carried out on all multidrug resistant isolates on agarose gel. All plasmid positive isolates were cured of their plasmids (100%) and post plasmid antibiogram carried out increased susceptibility pattern of isolates to the previously used antibiotics. Chromosomally mediated multidrug resistant strains were targeted against four selected different antibiotics to detect the resistant genes (TEM, gyrA, ereA and Blaoxa) expression patterns, with the use of polymerase chain reaction. Bivariate analysis of variance (Anova) using GraphPad InStat version 3.05 were employed to determine the significant differences in isolation, distribution and multidrug resistance of bacterial isolates from surgical wound specimens. Differences were considered significant at P < 0.05 showed that one hundred and twenty two (33.7%) surgical wound bacteria isolates which included four different genera (P. aeruginosa, E. coli, P. mirabilis and S. aureus) were recovered from postoperative surgical wound swab specimens. There were no significant differences (P>0.05) in the isolation of pathogens with respect to locations. Most bacteria exhibited resistance to Augmentin, Cefuroxime and cefixime from both locations and least resistance to Imipenem among the antibiotic discs tested against Gram negative isolates. The most predominant isolates from both locations were P. aeruginosa (UBTH=60%; NAUTH= 36%) and E. coli (UBTH=34%; NAUTH=52%). They exhibited high preponderance of multidrug resistance in both locations {P. aeruginosa, UBTH (90%), NAUTH (92%); E. coli, UBTH (70%), NAUTH (95%)}. There were no significant difference in the prevalence of TEM resistant genes expressed by the isolates in both locations (P value = 0.6). However most isolates from UBTH expressed TEM gene (OR = 9.7). Meanwhile gyrA resistant genes expressed by the isolates were significantly different (OR = 16.10; P = 0.014). S.aureus isolated from NAUTH expressed both Blaoxa and ereA resistant genes. There was a positive evidence of multidrug resistant genes from both locations which may constitutes a significant cause of morbidity in the study areas. Though phenotypic characterization may be reliable but molecular method is conclusive. Findings in this study justify the need to strengthen infection control and drug dispensing policies, and together force greater collaboration between microbiologists and medical practioners to prevent the spread of multidrug resistant bacteria.

Recently browsed