Detection of Vibrio anguillarum and Vibrio alginolyticus by Singleplex and Duplex Loop-Mediated Isothermal Amplification (LAMP) Assays Targeted to groEL and fklB Genes

Singleplex and duplex loop-mediated isothermal amplification (LAMP) assays were developed for detecting Vibrio anguillarum, a major bacterial pathogen of fish, and Vibrio alginolyticus, a pathogen of fish and humans, separately and simultaneously from contaminated seawater by targeting the groEL gene of V. anguillarum, which encodes a molecular chaperone protein, and the fklB gene of V. alginolyticus, which encodes a 22 kilodalton (kDa) peptidyl prolyl isomerase. The optimal reaction conditions to produce consistent results were 65°C for 30 min, 63°C for 30 min, and 63°C for 40 min for the groEL (singleplex for V. anguillarum), fklB (singleplex for V. alginolyticus), and groEL + flkB (duplex) LAMP assays, respectively, analyzed via visual detection methods (use of calcein, and SYBR Green I) and agarose gel electrophoresis. The assays were found to be species-specific, as closely related Vibrio spp. were not detected. The limits of detection (LoDs) of the LAMP assays for DNA template from pure culture and artificially contaminated seawater were 10 and 14 fg (groEL assay; for V. anguillarum), 12.5 and 17 fg (fklB assay; for V. alginolyticus), and 50 and 70 fg (duplex assay) per reaction, respectively, which were much better than the LoDs of conventional polymerase chain reaction (PCR). Singleplex and duplex LAMP assays were found to be rapid, species-specific, and sensitive for the detection of V. anguillarum and V. alginolyticus and are applicable to laboratory and field diagnostics

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Virulence factors and antimicrobial resistance in environmental strains of Vibrio alginolyticus

Vibrio alginolyticus has acquired increasing importance because this microorganism may be pathogenic to aquatic animals and humans. It has been reported that some V. alginolyticus strains carry virulence genes derived from pathogenic V. cholerae and V. parahaemolyticus strains. In this work V. alginolyticus was isolated from oyster samples acquired from a food-market in Mexico City. Thirty isolates were identified as V. alginolitycus. Strains showed β-haemolysis and proteolytic activity and produced a capsule. Strains displayed swimming and swarming motility and 93.3% of them produced siderophores. Several genes encoding virulence factors were detected using PCR amplification. These included proA, wza, vopD, vopB, hcp, vasH and vgrG genes, which were present in all strains. Other genes had a variable representation: tdh (86.6%), lafA (96.6%), pvsA (62%) and pvuA (16%). The trh gene could not be amplified from any of the strains. The antimicrobial resistance profile revealed that more than 90% of the strains were resistant to beta-lactams antibiotics, 60% to cephalotin, 45% to amikacin, 16% to cephotaxime, and 10% to pefloxacin, while 100% were susceptible to ceftriaxone. The V. alginolyticus strains isolated from oysters showed multiple resistance to antibiotics and several virulence factors described in well-characterized pathogenic vibrios (AU)

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Úlcera cutánea sobre radiodermitis crónica por Vibrio alginolyticus / Cutaneous Ulcer at the Site of Radiation-Induced Dermatitis Caused by Infection With Vibrio alginolyticus

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Prevalence of mobile genetic elements and transposase genes in Vibrio alginolyticus from the southern coastal region of China and theirrole in horizontal gene transfer

Vibrio alginolyticus has high genetic diversity, but little is known about the means by which it has been acquired. In this study, the distributions of mobile genetic elements (MGEs), including integrating conjugative elements (ICEs), superintegron-like cassettes (SICs), insertion sequences (ISs), and two types of transposase genes (valT1 and valT2), in 192 strains of V. alginolyticus were investigated. ICE, SIC, and IS elements, valT1, and valT2 were detected in 8.9%, 13.0%, 4.7%, 9.4%, and 2.6% of the strains, respectively. Blast searches and phylogenetic analysis of the acquired sequences of the ICE, SIC, IS elements and transposase genes showed that the corresponding homologues were bacterial and derived from extensive sources. The high prevalences of these MGEs in V. alginolyticus implied the extensive and frequent exchange of genes with environmental bacteria and that these elements strongly contribute to the genetic and phenotypic diversity of the bacterium. To our knowledge, this is the first report of V. alginolyticus harboring ICE and SIC elements (AU)

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