Antibiotic Resistance Patterns of Airborne Bacteria Isolated from Waste Dumpsites in Elele, Rivers State, Nigeria

Antibiotic resistance remains a critical global health concern, particularly in low- and middle-income countries where pharmaceutical misuse and inadequate waste management exacerbate the proliferation of resistant microorganisms. Environmental reservoirs such as open dumpsites are understudied sources of bioaerosol-borne pathogens with the potential to disseminate resistance genes. This study investigated the antibiotic resistance profiles of airborne bacterial isolates from waste dumpsites in Elele, Rivers State, Nigeria. Ten air samples were collected using the passive sedimentation method, including a control site located 10 meters from the dumpsites. Isolates were identified and subjected to antimicrobial susceptibility testing via the Kirby-Bauer disk diffusion method on Mueller-Hinton agar. Micrococcus spp. exhibited the highest susceptibility to chloramphenicol (36.00 mm) but displayed marked resistance to rifampicin (2.0 mm), levofloxacin (1.0 mm), and norfloxacin (9.0 mm). Escherichia coli were sensitive to gentamicin, streptomycin, and erythromycin (22.0 mm), but resistant to rifampicin, chloramphenicol, ampiclox, and levofloxacin (0–4 mm). Pseudomonas aeruginosa demonstrated extensive multidrug resistance, with susceptibility only to gentamicin and streptomycin (22.0 mm), and complete resistance to chloramphenicol and levofloxacin (0 mm). Serratia marcescens showed high susceptibility to ciprofloxacin, norfloxacin, gentamicin, amoxicillin, and streptomycin (22–26 mm), while exhibiting resistance to erythromycin, rifampicin, chloramphenicol, ampiclox, and levofloxacin (≤10 mm). Pseudomonas oleovorans was susceptible to ciprofloxacin, norfloxacin, gentamicin, amoxicillin, and streptomycin (20–25 mm), exhibited intermediate resistance to levofloxacin (13 mm), and was resistant to erythromycin, rifampicin, chloramphenicol, and ampiclox (0–12 mm). These findings highlight the significant presence of multidrug-resistant airborne bacteria in unmanaged waste sites, underscoring the environmental dimension of antimicrobial resistance and the need for strengthened surveillance and mitigation strategies.