Antibiotic and Cadmium Resistance Patterns in Non-fermentative Gram-Negative Bacilli Isolated from Hospital and Urban Wastewater

An anthropic pressure is exerted on water matrices due to the discharge of partially treated or untreated wastewater. Among the micropollutants found are heavy metals (HMs) which can induce the co-selection of antibiotic-heavy metal-resistant organisms, posing a serious public health problem. This study aimed to detect and characterize cadmium and carbapenem-resistant non-fermenting Gram-negative bacilli (NFGNB) isolated from urban and hospital wastewater. In this study, 52 NFGNB were isolated from urban wastewater (UWW, n = 24) and hospital wastewater (HWW, n = 28). Pseudomonas spp. (n = 32, 61.5%) and Acinetobacter spp. (n = 7. 13.5%) were the most frequently isolated. The MAR index varied from 0 (pansusceptible) to 0.81 (resistant to 13/16). Nine strains were resistant to carbapenems. PCR screening indicated that the A. baumannii S57 strain produced an OXA-23 carbapenemase, while the P. mendocina S119 produced a VIM M beta L. A total of 37 strains had MICs of cadmium >= 700 mu g/ml. This study explored the potential reservoirs of both types of effluent to harbor opportunistic bacteria considered to be emerging pathogens of the MDR cadmium-resistant phenotype constituting a double reservoir for the propagation of antibiotics (ATBs) and HM resistance genes.

Automated summary

An anthropic pressure on water matrices due to discharge of partially treated or untreated wastewater has led to the presence of micropollutants like heavy metals (HMs). These HMs can result in the co-selection of antibiotic-heavy metal-resistant organisms, causing a significant public health problem. This study aimed to identify and characterize cadmium and carbapenem-resistant non-fermenting Gram-negative bacilli (NFGNB) isolated from urban and hospital wastewater. The study isolated 52 NFGNB strains, with Pseudomonas spp. and Acinetobacter spp. being the most frequently found. The study also revealed the presence of carbapenem-resistant strains and the production of carbapenemases and metal resistance genes.