Aim The current study was conducted to determine the antimicrobial resistance profile and genetic relatedness of Aeromonas spp. isolated from healthcare and urban effluents, wastewater treatment plant (WWTP), and river water. Methods and results We detected the presence of genes conferring resistance to β‐lactam, quinolone, and aminoglycoside. Multilocus sequence typing (MLST) was carried out to differentiate the strains, and multilocus phylogenetic analysis (MLPA) was used to identify species. A total of 28 cefotaxime‐resistant Aeromonas sp. strains were identified, harboring uncommon Guiana‐Extended‐Spectrum (GES)‐type β‐lactamases (GES‐1, GES‐5, GES‐7, and GES‐16). Multidrug‐resistant Aeromonas spp. were found in hospital wastewater, WWTP, and sanitary effluent and A. caviae was identified as the most prevalent species (85.7%). Conclusion The release of untreated healthcare effluents, presence of antimicrobials in the environment, in addition to multidrug‐resistant Aeromonas spp., are all potential factors for the spread of resistance. Significance and impact of the sstudy We identified a vast repertoire of antimicrobial resistance genes in Aeromonas spp. from diverse aquatic ecosystems, including those that encode enzymes degrading broad‐spectrum antimicrobials widely used to treat healthcare‐associated infections. Hospital and sanitary effluents serve as potential sources of bacteria harboring antimicrobial resistance genes and are a threat to public health.

Key words: ESBL; CTX-M; Enterobacteriaceae

In the “One Health” approach, which encompasses human, animal, and environmental health, emerging issues of antimicrobial resistance are associated with hospital effluents that contain clinically relevant antibiotic-resistant bacteria along with a wide range of antibiotic concentrations, and lack regulatory status for mandatory prior and effective treatment. bla _GES genes have been reported in aquatic environments despite the low detection of these genes among clinical isolates within the studied hospitals. Carbapenemase enzymes, which are relatively unusual globally, such as GES type inserted into new integrons on plasmids, are worrisome.

Carbapenem-resistant Acinetobacter baumannii infection is a concern in developing countries due to high incidence, few therapeutic options, and increasing costs. Characterize and analyze the antibiotic susceptibility patterns of carbapenem-resistant A. baumannii isolates and evaluate clinical data of meningitis and bacteremia caused by this microorganism. Twenty-six A. baumannii isolates from 23 patients were identified by MALDI-TOF and automated methods and genotyped using pulsed field genotyping electrophoresis. Clinical data and outcomes were evaluated. Susceptibility of isolates to colistin, tigecycline, meropenem, imipenem, and doxycycline was determined. Mortality due to A. baumannii infections was 73.91%; all patients with meningitis and 7/8 patients with ventilator-associated pneumonia died. All isolates were susceptibility to polymyxin (100%; MIC50, MIC90: 1μg/mL, 1μg/mL) and colistin (100%; MIC50, MIC90: 2μg/mL, 2μg/mL), and 92% were susceptible to tigecycline (MIC50, MIC90: 1μg/mL, 1μg/mL) and doxycycline (MIC50, MIC90: 2μg/mL, 2μg/mL). blaOXA-23 was identified in 24 isolates. Molecular typing showed 8 different patterns: 13 isolates belonged to pattern A (50%). Carbapenem-resistant A. baumannii infections mortality is high. Alternative antimicrobial therapy (doxycycline) for selected patients with carbapenem-resistant A. baumannii infection should be considered.