Occurrence and antibiotic resistance pattern of gram-negative bacteria isolated from restaurant table surfaces

Abstract

Pathogenic bacteria present on frequently touched surfaces represent a significant public health concern, particularly due to their potential to spread antibiotic-resistant infections. This study aimed to isolate and characterize pathogenic bacteria from restaurant (15 restaurant table surfaces) in Dhaka city and to evaluate their antibiotic susceptibility patterns. A total of Acinetobacter, Escherichia coli (N=5), Salmonella spp. (N=6), Shigella spp. (N=15), Vibrio spp. (N=14), Klebsiella pneumoniae (N=18), and Staphylococcus aureus (N=1) were analyzed against six commonly used antibiotics: Vancomycin, Amoxicillin, Azithromycin, Cefepime, Kanamycin, and Tetracycline. All Gram-negative isolates demonstrated 100% resistance to Vancomycin, indicating its ineffectiveness against these organisms. High resistance to Amoxicillin was observed among E. coli (80%), Salmonella spp. (83%), Shigella spp. (87%), Vibrio spp. (64%), and K. pneumoniae (83%). In contrast, Kanamycin, Cefepime, and Tetracycline showed comparatively higher effectiveness, particularly against E. coli, Shigella spp., Vibrio spp., and K. pneumoniae. Klebsiella pneumoniae exhibited the highest sensitivity to Cefepime (84%), while Shigella spp. showed notable sensitivity to Kanamycin (80%) and Cefepime (74%). Intermediate susceptibility was most prominent for Azithromycin and Cefepime across several isolates, especially in Salmonella spp. and Vibrio spp. The single Staphylococcus aureus isolate showed complete resistance to Vancomycin and Amoxicillin but remained fully sensitive to Azithromycin, Cefepime, and Tetracycline. Although identification and resistance profiling were based on conventional microbiological and phenotypic methods, molecular confirmation using polymerase chain reaction (PCR) targeting species-specific genes and antibiotic resistance determinants would further enhance the accuracy and reliability of pathogen identification. Overall, the findings highlight the presence of multidrug-resistant pathogenic bacteria on restaurant table surfaces, emphasizing the need for improved hygiene practices, molecular surveillance, and continuous monitoring of antibiotic resistance to reduce public health risks.