Antimicrobial resistance is a public health concern affecting human, animal, and environmental health. Antimicrobial-resistant pathogens, such as Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli (ESKAPEE), the most important microorganisms involved in healthcare-related infections, can be excreted by patients into hospital effluent which then becomes a reservoir for these pathogens. In this context, we characterized and compared resistant microorganisms of the ESKAPEE group, isolated from hospital effluent and clinical samples from patients of the Pequeno Príncipe Hospital, located at Curitiba, Paraná. Out of 345 microorganisms isolated, 208 from the ESKAPEE group were obtained from hospital effluent and 18 were from clinical samples. Among them, K. pneumoniae was the most frequently identified microorganism in both clinical and environmental settings. The genomic context of the resistance of 52 single-clone isolates with satisfactory genome assembly parameters was analyzed. The identified carbapenem resistance genes were bla_KPC-2,bla_GES-5, and bla_NDM-1. Two Enterobacter kobei isolates co-produced the carbapenemases bla_KPC-2 and bla_GES-5. The samples were defined as polyclonal for K. pneumoniae and E. cloacae complexes and clonal for E. coli isolates. ST392 and ST11 were identified in both clinical and environmental samples of K. pneumoniae that produces Klebsiella pneumoniae carbapenemase (KPC) or New Delhi metallo-β-lactamase (NDM), suggesting the persistence of these microorganisms in hospital effluents. The ESKAPEE group is present in hospitals, and its dissemination through hospital effluents is a significant concern due to its capacity to transfer antimicrobial resistance genes, which poses a risk to public health and food safety.

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.

Multidrug-resistant (MDR) Klebsiella pneumoniae (Kp) is a major bacterial pathogen responsible for hospital outbreaks worldwide, mainly via the spread of high-risk clones and epidemic resistance plasmids. In this study, we evaluated the molecular epidemiology and β-lactam resistance mechanisms of MDR-Kp strains isolated in a Brazilian academic care hospital. We used whole-genome sequencing to study drug resistance mechanisms and their relationships with a K. pneumoniae carbapenemase-producing (KPC) Kp outbreak. Forty-three Kp strains were collected between 2003 and 2012. Antimicrobial susceptibility testing was performed for 15 antimicrobial agents, and polymerase chain reaction (PCR) was used to detect 32 resistance genes. Mutations in ompk35, ompk36, and ompk37 were evaluated by PCR and DNA sequencing. Pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were carried out to differentiate the strains. Based on distinct epidemiological periods, six Kp strains were subjected to whole-genome sequencing. β-lactamase coding genes were widely distributed among isolates. Almost all isolates had mutations in porin genes, particularly ompk35. The presence of bla_KPC promoted a very high increase in carbapenem minimum inhibitory concentration only when ompk35 and ompk36 were interrupted by insertion sequences. A major cluster was identified by PFGE analysis and all isolates from this cluster belonged to clonal group (CG) 258. We have also identified a large repertoire of resistance genes in the sequenced isolates. A bla_KPC–2-bearing plasmid (pUFPRA2) was also identified, which was very similar to a plasmid previously described in the first Brazilian KPC-Kp (2005). We found high-risk clones (CG258) and an epidemic resistance plasmid throughout the duration of the study (2003 to 2012), emphasizing a persistent presence of MDR-Kp strains in the hospital setting. Finally, we found that horizontal transfer of resistance genes between clones may have played a key role in the evolution of the outbreak.

We investigated the molecular mechanisms underlying azole resistance in seven Candida tropicalis isolates that caused candidemia and candiduria in Paraná, Brazil (2016–2022). Biofilm production, antifungal susceptibility testing, multilocus sequence typing, amplification and sequencing of ERG11, and quantification of ERG11, MDR1, and CDR1 expression levels were performed. Notably, five isolates (71.4%) were from urine samples and two (28.6%) were from blood samples. All strains were biofilm producers, with levels ranging from moderate to strong. The minimum inhibitory concentration (MIC) values ranged from 8–>64 mg/L for fluconazole and 0.25–1 mg/L for voriconazole. All isolates had mutations in ERG11; Y132F and Y257N were predominant (71.4%), followed by Y132F and S154F (14.3%) and Y257H (14.3%). No differences in ERG11 expression were found between the susceptible and resistant groups, but MDR1 and CDR1 were more highly expressed in the susceptible isolates. All the isolates contained previously unassigned diploid sequence types. The emergence of C. tropicalis azole resistance has been previously described in Brazil; however, the presence of resistant isolates in urine highlights the need for surveillance resistant strains in both urinary and invasive contexts. In our study mutations in ERG11 were the main resistance mechanism identified in C. tropicalis.

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.