RESUMO
Sichuan is a significant aquaculture province in China, with a total aquaculture output of 1.72 × 106 tons in 2022. One of the most significant microorganisms hurting the Sichuan aquaculture is Aeromonas hydrophila, whose genotype and antibiotic resistance are yet unknown. This study isolated a total of 64 strains of A. hydrophila from various regions during September 2019 to June 2021 within Sichuan province, China. The technique of Multi-Locus Sequence Typing (MLST) was used for the purpose of molecular typing. Meanwhile, identification of antibiotic resistance phenotype and antibiotic resistance gene was performed. The findings of the study revealed that 64 isolates exhibited 29 sequence types (ST) throughout different regions in Sichuan, with 25 of these ST types being newly identified. Notably, the ST251 emerged as the predominant sequence type responsible for the pandemic. The resistance rate of isolated strains to roxithromycin was as high as 98.3%, followed by co-trimoxazole (87.5%), sulfafurazole (87.5%), imipenem (80%), amoxicillin (60%), and clindamycin (57.8%). Fifteen strains of A. hydrophila exhibited resistance to medicines across a minimum of three categories, suggesting the development of multidrug resistance in these isolates. A total of 63 ARGs were detected from the isolates, which mediated a range of antibiotic resistance mechanisms, with deactivation and efflux potentially serving as the primary mechanisms of antibiotic resistance. This study revealed the diversity of A. hydrophila genotypes and the risk of antibiotic resistance in Sichuan, providing reference for scientific and effective control of A. hydrophila infection.
Assuntos
Aeromonas hydrophila , Aeromonas , Aeromonas hydrophila/genética , Tipagem de Sequências Multilocus , Resistência Microbiana a Medicamentos , Genótipo , Fenótipo , Antibacterianos/farmacologia , China , Aeromonas/genéticaRESUMO
Wastewater treatment plants (WWTPs) are recognized as important sources of Antibiotic Resistant Bacteria (ARBs) and Antibiotic Resistant Genes (ARGs), and might play a role in the removal and dissemination of antimicrobial resistance (AMR) in the environment. Detailed information about AMR removal by the different treatment technologies commonly applied in urban WWTPs is needed. This study investigated the occurrence, removal and characterization of ARBs in WWTPs employing different technologies: WWTP-A (conventional activated sludge-CAS), WWTP-B (UASB reactor followed by biological trickling filter) and WWTP-C (modified activated sludge followed by UV disinfection-MAS/UV). Samples of raw sewage (RI) and treated effluent (TE) were collected and, through the cultivation-based method using 11 antibiotics, the antibiotic resistance profiles were characterized in a one-year period. MAS was effective in reducing ARB counts (2 to 3 log units), compared to CAS (1 log unit) and UASB/BTF (0.5 log unit). The composition of cultivable ARB differed between RI and TE samples. Escherichia was predominant in RI (56/118); whilst in TE Escherichia (31/118) was followed by Bacillus (22/118), Shigella (14/118) and Enterococcus (14/118). Most of the isolates identified (370/394) harboured at least two ARGs and in over 80 % of the isolates, 4 or more ARG (int1, blaTEM, TetA, sul1 and qnrB) were detected. A reduction in the resistance prevalence was observed in effluents after CAS and MAS processes; whilst a slight increase was observed in treated effluents from UASB/BTF and after UV disinfection stage. The multi-drug resistance (MDR) phenotype was attributed to 84.3 % of the isolates from RI (27/32) and 63.6 % from TE (21/33) samples and 52.3 % of the isolates (34/65) were resistant to carbapenems (imipenem, meropenem, ertapenem). The results indicate that treated effluents are still a source for MDR bacteria and ARGs dissemination to aquatic environments. The importance of biological sewage treatment was reinforced by the significant reductions in ARB counts observed. However, implementation of additional treatments is needed to mitigate MDR bacteria release into the environment.
Assuntos
Esgotos , Purificação da Água , Esgotos/microbiologia , Antagonistas de Receptores de Angiotensina/farmacologia , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/análise , Brasil , Genes Bacterianos , Antibacterianos/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Bactérias/genética , Farmacorresistência Bacteriana MúltiplaRESUMO
OBJECTIVES: Earlier studies have demonstrated the use of inactivated recombinant E. coli (bacterins), to protect against Clostridium spp. in vaccinated animals. These bacterins have a simpler, safer, and faster production process. However, these bacterins carry expression plasmids, containing antibiotic resistance gene, which could be assimilate accidentally by environmental microorganisms. Considering this, we aimed to impair this plasmids using formaldehyde at different concentrations. RESULTS: This compound inactivated the highest density of cells in 24 h. KanR cassette amplification was found to be impaired with 0.8% for 24 h or 0.4% for 72 h. Upon electroporation, E. coli DH5α ultracompetent cells were unable to acquire the plasmids extracted from the bacterins after inactivation procedure. Formaldehyde-treated bacterins were incubated with other viable strains of E. coli, leading to no detectable gene transfer. CONCLUSIONS: We found that this compound is effective as an inactivation agent. Here we demonstrate the biosafety involving antibiotic resistance gene of recombinant E. coli vaccines allowing to industrial production and animal application.
Assuntos
Escherichia coli/genética , Formaldeído/farmacologia , Resistência a Canamicina/efeitos dos fármacos , Plasmídeos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Vacinas contra Escherichia coli/efeitos adversos , Vacinas contra Escherichia coli/genética , Transferência Genética Horizontal/efeitos dos fármacos , Plasmídeos/genética , Vacinas de Produtos Inativados , Vacinas SintéticasRESUMO
The worldwide dispersion and sudden emergence of new antibiotic resistance genes (ARGs) determined the need in uncovering which environment participate most as their source and reservoir. ARGs closely related to those currently found in human pathogens occur in the resistome of anthropogenic impacted environments. However, the role of pristine environment as the origin and source of ARGs remains underexplored and controversy, particularly, the marine environments represented by the oceans. Here, due to the ocean nature, we hypothesized that the resistome of this pristine/low-impacted marine environment is represented by distant ARG homologs. To test this hypothesis we performed an in silico analysis on the Global Ocean Sampling (GOS) metagenomic project dataset focusing on the metallo-ß-lactamases (MßLs) as the ARG model. MßLs have been a challenge to public health, since they hydrolyze the carbapenems, one of the last therapeutic choice in clinics. Using Hidden Markov Model (HMM) profiles, we were successful in identifying a high diversity of distant MßL homologs, related to the B1, B2, and B3 subclasses. The majority of them were distributed across the Atlantic, Indian, and Pacific Oceans being related to the chromosomally encoded MßL GOB present in Elizabethkingia genus. It was observed only a reduced number of metagenomic sequence homologs related to the acquired MßL enzymes (VIM, SPM-1, and AIM-1) that currently have impact in clinics. Therefore, low antibiotic impacted marine environment, as the ocean, are unlikely the source of ARGs that have been causing enormous threat to the public health.