Antibiotic resistance profiles in cultivable microbiota isolated from some romanian natural fishery lakes included in Natura 2000 network

Abstract

Background The present study aims the characterization of antibiotic resistance phenotypes and encoding genes in bacterial strains isolated from some Romanian aquatic fishery lowland salted lakes. Material/Methods This study was conducted on 44 bacterial strains, mainly belonging to species used as microbiological indicators of fecal pollution isolated from four natural fishery lakes. All strains were tested for their antibiotic susceptibility by disk diffusion method. Simplex and multiplex PCR were performed to identify the β-lactams antibiotic resistance genes (blaNMD, blaOXA−48, blaVIM, blaIMP, blaCTX−M, blaTEM), sulfonamides (Sul1, Sul2), tetracyclines (TetA, TetB, TetC, TetD, TetM), aminoglycosides (aac3Ia), vancomycin (VanA, VanB, VanC), macrolides (ermA, ermB, ermC) as well as the plasmid-mediated quinolone resistance (PMQR) markers (QnrA, QnrB, QnrS), and class 1 integrons (Int1, drfA1-aadA1). Results The Enterococcus spp. isolates exhibited phenotypic resistance to vancomycin (35 %) and macrolides (erythromycin) (75 %); from the vancomycin – resistant strains, 5 % harboured VanA (E. faecalis), while the erythromycin resistant isolates were positive for the ermA gene (E. faecalis − 10 %, E. faecium − 5 %). The Gram- negative rods (GNR) exhibited a high level of resistance to β-lactams: cefuroxime (63 %), cefazolin (42 %), ceftriaxone (8 %), ceftazidime and aztreonam (4 % each). The genetic determinants for beta-lactam resistance were represented by blaCTX−M−like (33 %), blaNDM−like and blaIMP−like (8.33 %) genes. The resistance to non-β-lactam antibiotics was ascertained to the following genes: quinolones (QnrS − 4.16 %); sulfonamides (Sul1–75 %, Sul2–4.16 %); aminoglycosides (aac3Ia − 4.16 %); tetracyclines (tetA – 25 %, tetC − 15 %). The integrase gene was found in more than 50 % of the studied strains (58.33 %). Conclusions The cultivable aquatic microbiota from fishery lakes is dominated by enterococci and Enterobacterales strains. The GNR strains exhibited high levels of β-lactam resistance mediated by extended spectrum beta-lactamases and metallo-β-lactamases. The Enterococcus sp. isolates were highly resistant to macrolides and vancomycin. The high level and diversity of resistance markers, correlated with a high frequency of integrons is suggesting that this environment could act as an important reservoir of antibiotic resistance genes with a great probability to be horizontally transmitted to other associated species from the aquatic sediments microbiota, raising the potential zoonotic risk for fish consumers.

Nationwide Surveillance on Antimicrobial Resistance Profiles of Enterococcus faecium and Enterococcus faecalis Isolated from Healthy Food Animals in South Korea, 2010 to 2019

“…Macrolide-lincosamide-streptogramin antibiotics constitute an alternative therapy for the treatment of insidious enterococcal infections [43]. We noted high erythromycin and tylosin resistance in E. faecium isolated from chickens and E. faecalis from pigs and chickens.…”

Molecular Typing Reveals Environmental Dispersion of Antibiotic-Resistant Enterococci under Anthropogenic Pressure

“…Very few Romanian studies concerning antimicrobial resistance of enterococci have been published. Clinical variants of Enterococcus showed a high resistance profile for fluoroquinolones and penicillins [ 27 , 28 ], while bacterial clones from fishery lakes were highly resistant to macrolides [ 29 ]. Vancomycin resistance recently emerged in this One-Health continuum.…”

Temporo-spatial variations in resistance determinants and clonality of Acinetobacter baumannii and Pseudomonas aeruginosa strains from Romanian hospitals and wastewaters

“…Also, we have demonstrated the spread of K. pneumoniae ST101 from hospital to wastewater influent and its persistence in the wastewater effluent after the chlorine treatment, suggesting its dissemination in the community and in different aquatic compartments [ 63 ]. Our previous research showed that enterococci and Enterobacterales strains in four Romanian natural aquatic fishery lowland salted lakes from Natura 2000 Network carried a high diversity of resistance markers correlated with class 1 integrons [ 64 ]. Other authors described tetracycline and sulfonamides ARGs in the WWTP and the receiver river from northwestern Romania and demonstrated that some ARGs, such as bla VIM and bla SHV could persist in the chlorinated hospital wastewater, being detected both in the influent and chlorinated effluent [ 65 , 66 ].…”