Utilização de marcadores fenogenotípicos de virulência na caracterização de Vibrio spp. isolados a partir de mexilhões (Perna perna) em diferentes pontos do litoral do Rio de Janeiro

Abstract

Mussels are bivalve filtrating mollusks, which feed of microorganism uptaken from the water current, and it is not a selective mechanism, so mussels microbiological analysis shows up the aquatic environment quality. The objective of the study was to characterize the bacterial species of public health importance associated with bivalve mollusks incrustated in underwater cable and into the coastal rocks of Arquipélago de Santana, Macaé, and mariculture farms in Angra dos Reis of Ilha Grande and Arraial do Cabo, all in Rio de Janeiro State. Associated with this, the present study aimed to detect antimicrobial resistance profile of bacterial isolates and virulence markers and genes from Vibrio spp. Characterization was performed by detecting of target gene (rpoA), found in all strains of Vibrio, species specific genes (tlh and cth) and virulence genes (tdh, trh and cth). It was evaluated the water quality for possible contamination from fishing activities and underwater. Seven samples were taken and obtained a total of 209 strains of Vibrio spp., represented by Vibrio parahaemolyticus 40.66% (85/209), Vibrio alginolyticus 19.6% (41/209), Vibrio vulnificus 12.4% ( 26/209) and other species 27.2% (57/209). Was detected 91.3% (191/209) ampicillin resistance, 23.9% (50/209) to ciprofloxacin, 18.6% (39/209) to nitrofurantoin, 5.7% (12/209) to tetracycline, 4.3% (9/209) to pefloxacin and 3.3% (7/209) to chloramphenicol. All 209 isolates phenotypically identified as Vibrio spp. amplified rpoA gene, generating a fragment of 242 bp. The tlh gene was detected in 40.6% (85/209) of the isolated Vibrio spp., all phenotypically identified as V. parahaemolyticus. Among 85 strains of Vibrio parahaemolyticus, the tdh gene was detected in 68.2% (58/85), and the trh gene was not detected. The cth gene was detected in 12.5% (26/209) of isolates, all identified phenotypically as V. vulnificus, amplifying a fragment of 386 bp. The correlation between the fenotipic and genotypic identification of the Vibrio spp. strains with the sequencing data was obtained in 50% (4/8) of isolates. In isolates whithout correlation (4/8) biochemical assays and genotypic identification based on speciesspecific genes tests were applied to identify the isolates. The detection of Enterobacteriaceae achieved a total of 88 isolates, represented by 29.5% (26/88) of Escherichia coli, 10.2% (9/88) of Enterobacter agglomerans and Enterobacter cloacae, 9.1% (8/88) of Citrobacter diversus, 7.9% (7/88) of Enterobacter aerogenes, 5.7% (5/88) of Proteus vulgaris, 4.5% (4/88) of Serratia rubidae, Enterobacter sakazakii and Citrobacter freundii, 3.4% (3/88) of Hafnia alvei, 2.3% (2/88) of Serratia marcencens, Klebsiella oxytoca, Morganella morganii and Yersinia enterocolitica and 1.1% (1/88) of Proteus mirabilis. Also, it was detetecetd 64.7% (57/88) ampicillin resistance, 39.7% (35/88) to cephalothin, 30.7% (27/88) to gentamicin, 26.1% (23/88) to cefoxitin, 15.9% (14/88) to ceftriaxone and tetracycline, 13.6% (12/88) to chloramphenicol, 11.4% (10/88) to ciprofloxacin, 7.9% (7/88) to ampicillin and sulbactam, aztreonam, and 1.1% (1/88) to imipenem. Microbiological analysis of seawater revealed presence of coliforms in 50% (4/8) of samples from Arraial do Cabo. A total of 12 strains of Aeromonas spp. were detected. Due to intrinsic pathogenicity of some bacterial species, plus the antibiotics resistance, it is important the microbiological evaluation of mussels for their monitoring, ensuring the safety of handlers and consumers.