Characteristics of Escherichia coli Exposed to Pseudomonas aeruginosa-Inoculated Medium Pretreated with Herbal Medicine
Raymond, Obumneme Dominic
Department of Medical Microbiology, Rivers State University, Port Harcourt, Nigeria.
Monsi Tombari Pius
Department of Medical Microbiology, Rivers State University, Port Harcourt, Nigeria.
Giami, Lynda Kadi *
Department of Medical Microbiology, Rivers State University, Port Harcourt, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
The acquisition and dissemination of antimicrobial resistance remain major challenges in the clinical management of bacterial infections. This study investigated the phenotypic characteristics of Escherichia coli following exposure to Pseudomonas aeruginosa–secreted products, with and without pretreatment using Ruzu herbal bitters. E. coli isolates were cultured in Tryptic Soy Broth containing P. aeruginosa secreted products alone (P+B) or in combination with Ruzu herbal bitters (P+B+R) and compared with a negative control (B). Antimicrobial susceptibility testing using the disc diffusion method revealed reduced zones of inhibition against gentamicin and ceftriaxone in treated isolates relative to the control, with ceftriaxone exhibiting greater activity than gentamicin. Biofilm assessment using the 24-well plate method showed enhanced biofilm formation in both treated conditions, with the highest biofilm density observed in isolates exposed to the combined herbal and P. aeruginosa secreted products. Viable plate counts further demonstrated increased bacterial growth under combined treatment, followed by exposure to P. aeruginosa secreted products alone. Overall, the findings indicate that exposure to P. aeruginosa secreted factors, particularly in the presence of herbal pretreatment, enhances E. coli growth and biofilm formation, which may contribute to reduced antimicrobial susceptibility.
Keywords: Escherichia coli, pseudomonas aeruginosa-inoculated medium, pretreatment, herbal drug