Comparative susceptibility of veliger larvae of four bivalve mollusks to a Vibrio alginolyticus strain

The susceptibility of 7 d old veliger larvae of the scallops Argopecten ventricosus and Nodipecten subnodosus, the penshell Atrina maura, and the Pacific oyster Crassostrea gigas to a pathogenic strain of Vibrio alginolyticus was investigated by challenging the larvae with different bacterial concentrations in a semi-static assay. The results indicate that the larvae of the 2 scallop species are more susceptible to the V. alginolyticus strain than those of the oyster and the penshell. Signs of the disease were similar to bacillary necrosis described in previous work. Interspecies differences in susceptibility to pathogens are discussed.     

Phenotypic characterization and RAPD fingerprinting of Vibrio parahaemolyticus and Vibrio alginolyticus isolated during Tunisian fish farm outbreaks

The genus Vibrio is characterized by a large number of species and some of them are human pathogens causing gastrointestinal and wound infections through the ingestion or manipulation of contaminated fishes and shellfish including Vibrio parahaemolyticus and Vibrio alginolyticus. In this study, we reported the phenotypic and molecular characterization of 9 V. parahaemolyticus and 27 V. alginolyticus strains isolated from outbreaks affecting cultured Gilthead sea bream (Sparus aurata L.) and Sea bass (Dicentrarchus labrax) along the Tunisian coast from 2008 to 2009. All isolates were tested for the presence of DNase, caseinase, protease, lipase, amylase, gelatinase, hemolytic activity and antibacterial resistance to different drugs. Randomly amplified polymorphic DNA was used to examine the genetic relatedness among the V. parahaemolyticus and V. alginolyticus strains.     

Isolation of thermophilic fungal strains producing oxido-reductase and hydrolase enzymes from various Tunisian biotopes

The present study surveys 37 thermophilic fungal strains, that were isolated from various Tunisian biotopes such as litter, husk and compost, for their involvement in lignin degradation activities. Oxido-reductase and hydrolase activities were screened. Oxido-reductase activities, such as Extracellular Oxidase, Laccase, Tyrosinase and Peroxidase, were tested. Hydrolase activities, namely Lipase, Protease, Amylase and Cellulase, were also revealed. Strain ST26, isolated from locally made compost, and showed an important laccase activity with ABTS and DMP, was selected. Laccase activity of strain ST26 was 1575 U/l in liquid media. This strain was identified and was belonging to Scytalidium genus and more precisely to the specie Scytalidium thermophilum using 5.8S rRNA gene sequencing analysis.     

Immunotropic properties of exoglycan obtained from the marine micro-organism Vibrio alginolyticus]

Immune system modulating activity of exoglycane isolated from culture media of Vibrio alginolyticus (strain 945-80) was investigated. The substance demonstrated stimulating activity on the humoral and cell immune system, potentiated phagocyte activity of macrophage and neutrophils, increased survival index of the animals infected by Gram-positive and Gram-negative bacteria.     

Differentiation of Vibrio alginolyticus strains isolated from Sardinian waters by ribotyping and a new rapid PCR fingerprinting method

We investigated the usefulness of a novel PCR fingerprinting technique, based on the specific amplification of genomic regions, to differentiate 30 Vibrio alginolyticus strains isolated in Sardinian waters. The different profiles obtained were scanned and analyzed by a computer program in order to determine genetic relationships. The results were then compared with the patterns obtained by ribotyping with HindIII, KpnI, and XbaI restriction enzymes. PCR fingerprinting could differentiate the strains analyzed into 12 different patterns, whereas ribotyping with XbaI, which produced the highest number of patterns, generated only 7 different profiles. This study revealed the superior discriminative power of the proposed technique for the differentiation of related V. alginolyticus strains and the potential use of PCR fingerprinting in epidemiological studies.     

Characterization and distribution of Vibrio alginolyticus and Vibrio parahaemolyticus isolated in Indonesia

Previous studies have shown that Vibrio alginolyticus and Vibrio parahaemolyticus can be isolated from similar types of marine samples. In this report, the results of an examination of 567 V. alginolyticus and V. parahaemolyticus strains, isolated from seawater in Jakarta Bay and from more than 30 types of seafood from markets in Jakarta, Indonesia, are presented. Most isolates were from mackerel, shrimp, or squid. Numerical taxonomic analyses clustered 337 isolates and three V. alginolyticus reference strains at S greater than or equal to 80%. These strains produced acid from sucrose, but only approximately 80% produced acetoin or grew in the presence of 10% NaCl. The frequency of occurrence of V. alginolyticus in seawater samples ranged from 0% (in February and March 1972) to 100% (in September and December 1972) and was highest in seafood samples from August to December 1972. A second cluster of 230 isolates and seven V. parahaemolyticus reference strains was observed at S greater than or equal to 82%. These strains did not produce acetoin or acid from sucrose, and approximately 20% grew in the presence of 10% NaCl. V. parahaemolyticus was detected in seawater samples each month, with the highest frequency of occurrence (83.3%) in May 1972. Twenty-nine K antigen serotypes were demonstrated in V. parahaemolyticus isolates, and another 40% were untypable. The modal antibiotic resistance pattern for each species included five drugs. Only 12% of the V. parahaemolyticus strains were Kanagawa positive, and 10% elicited fluid accumulation in ligated rabbit ileal loops. All of the 7 V. alginolyticus strains and 94 (70%) of the V. parahaemolyticus strains tested killed mice when inoculated intraperitoneally.(ABSTRACT TRUNCATED AT 250 WORDS)     

Occurrence of antibiotic and metal resistance and plasmids in Bacillus strains isolated from marine sediment

Eleven hundred Bacillus strains isolated from marine sediment from the Minas Basin, Nova Scotia, Canada, were purified on LB agar supplemented with ampicillin, chloramphenicol, erythromycin, streptomycin, tetracycline, or mercuric chloride. Seventy-seven isolates were examined for plasmid DNA, and for resistance to 11 antibiotics, HgCl2, and phenylmercuric acetate. Minimum inhibitory concentrations of Ag, Cd, Co, Cu, and Zn were also determined. Forty-three percent of antibiotic- and mercury-resistant strains contained one or more plasmids ranging from 1.9 to 210 MDa. Fifty-four percent carried plasmids greater than 20 MDa, and 97% were resistant to two or more metals. There was no correlation between plasmid content and resistance either to antibiotics or to mercurial compounds in these strains. Mercury-resistant isolates were unable to transform Hg2+ to volatile Hg0 by virtue of a mercuric reductase enzyme system (mer). Strains resistant to Hg2+ were investigated for their ability to produce H2S and intracellular acid-labile sulfide when grown in the absence and presence of HgCl2. Lower levels of H2S and intracellular sulfide were detected only in metal-resistant strains grown in the presence of HgCl2, suggesting that cellular sulfides complexed with Hg2+ in these strains.     

A Comparative Study of the Sugar Composition of O-antigenic Lipopolysaccharides Isolated from Vibrio alginolyticus and Vibrio parahaemolyticus

A comparative study of the sugar composition of O-antigenic lipopolysaccharides (LPS) isolated from Vibrio alginolyticus and those from V. parahaemolyticus was carried out. 3-Deoxy-d-mannooctulosonic acid, 2-keto-3-deoxy octonate (KDO), a regular sugar constituent of gram-negative bacterial LPS, was totally absent from LPS of all V. alginolyticus strains examined as it was from those of V. parahaemolyticus. Furthermore, a KDO-like thiobarbituric acid test-positive substance, identical with that of either V. parahaemolyticus 07 or 012, was also found in LPS from three strains, 505–78, 905–78, and 1013–79 (designated tentatively as group I), out of the five strains of V. alginolyticus tested. LPS from the members of group I contained, as component sugars, glucose, galactose, l-glycero-d-manno-heptose, glucosamine, galactosamine, the KDO-like substance, and an unidentified amino sugar P1. Thus, LPS of the members of group I possessed a similar sugar composition which is similar to that of LPS from either V. parahaemolyticus 07 or 012. LPS of strain 1027–79, one of the other two strains (designated tentatively as gorup II), contained as component sugars, glucose, l-glycero-d-mannoheptose, glucosamine, galactosamine, and the other unidentified amino sugar P2, while LPS of strain 53–79, the other member of group II, contained galactose as an additional component. The results indicate that LPS of strain 1027–79 has a sugar composition similar to that of V. parahaemolyticus 09 LPS.     

溶藻弧菌质粒pVAE259全序列测定与分子生物学特征分析

【目的】获得溶藻弧菌环状质粒pVAE259全序列,分析其分子生物学特征并探索该质粒可能具备的功能。【方法】使用酶切、克隆测序的方法获得pVAE259的全序列,利用软件分析DNA序列和可能的编码蛋白,推测质粒的生物学信息。【结果】pVAE259为闭合环状质粒,全长6,075 bp,GC含量为42.16%。在NCBI中比对发现pVAE259与Vibriosp.41隐蔽性质粒pPS41具有较高的相似性。我们在序列中找到一个oriT位点,另外全序列的4118-5494 bp推测为质粒复制区域。pVAE259中存在7个氨基酸序列长度大于100的开放式阅读框(ORF):ORF1-ORF7。其中ORF1编码蛋白属于释放酶超级家族(Relaxase Super-family)蛋白,在NCBI数据库中它与大肠杆菌(Escherichia coli)的MobA-like蛋白最相似;ORF2编码蛋白属于复制酶超级家族(Replicase Super-family),它与嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia)的复制蛋白RepA最相似;ORF5与伸长盐单胞菌(Halomonas elongata)质粒pHE1的转移蛋白MobC相似。【结论】根据上述结果及相关文献分析,pVAE259可能是具有转移能力的质粒,该质粒是否影响宿主菌的表型性状还不清楚。     

Virulence of Vibrio vulnificus strains from marine environments

Vibrio vulnificus strains isolated from geographically diverse marine sources were compared with clinical isolates for phenotype and in vitro and in vivo production of virulence factors. There were no differences between environmental and clinical strains on the basis of biochemical characteristics or antimicrobial susceptibility patterns. Cytolysin and cytotoxin titers produced by environmental strains were generally comparable to those of clinical strains. Of 29 environmental isolates tested, 25 were pathogenic for mice. These data show that environmental V. vulnificus strains are phenotypically indistinguishable from clinical isolates and that approximately 90% of the environmental strains tested produced in vitro virulence factors and in vivo pathogenicity for mice comparable to those produced by clinical V. vulnificus isolates.     

A comparison of four susceptibility tests on Yersinia enterocolitica strains isolated from human and animal material

The results of antibiotic sensitivity tests are presented for 20 strains of Yersinia enterocolitica from human and animal material as well as for one commercial standard strain. Results obtained with four different methods of assays were compared. One of the methods used was flow cytometric Minimum Inhibitory Concentration (MIC) assay (FC-MIC). Results of all four tests were comparable and were in range for Gentamycin sensitive strains. Problems of resistant bacterial strains in the clinical surrounding are discussed.     

Characterization and distribution of Vibrio alginolyticus and Vibrio parahaemolyticus isolated in Indonesia.

Previous studies have shown that Vibrio alginolyticus and Vibrio parahaemolyticus can be isolated from similar types of marine samples. In this report, the results of an examination of 567 V. alginolyticus and V. parahaemolyticus strains, isolated from seawater in Jakarta Bay and from more than 30 types of seafood from markets in Jakarta, Indonesia, are presented. Most isolates were from mackerel, shrimp, or squid. Numerical taxonomic analyses clustered 337 isolates and three V. alginolyticus reference strains at S greater than or equal to 80%. These strains produced acid from sucrose, but only approximately 80% produced acetoin or grew in the presence of 10% NaCl. The frequency of occurrence of V. alginolyticus in seawater samples ranged from 0% (in February and March 1972) to 100% (in September and December 1972) and was highest in seafood samples from August to December 1972. A second cluster of 230 isolates and seven V. parahaemolyticus reference strains was observed at S greater than or equal to 82%. These strains did not produce acetoin or acid from sucrose, and approximately 20% grew in the presence of 10% NaCl. V. parahaemolyticus was detected in seawater samples each month, with the highest frequency of occurrence (83.3%) in May 1972. Twenty-nine K antigen serotypes were demonstrated in V. parahaemolyticus isolates, and another 40% were untypable. The modal antibiotic resistance pattern for each species included five drugs. Only 12% of the V. parahaemolyticus strains were Kanagawa positive, and 10% elicited fluid accumulation in ligated rabbit ileal loops. All of the 7 V. alginolyticus strains and 94 (70%) of the V. parahaemolyticus strains tested killed mice when inoculated intraperitoneally.(ABSTRACT TRUNCATED AT 250 WORDS)     

Recent progress in the Na(+)-translocating NADH-quinone reductase from the marine Vibrio alginolyticus

The respiratory chain of Gram-negative marine and halophilic bacteria has a Na(+)-dependent NADH-quinone reductase that functions as a primary Na(+) pump. The Na(+)-translocating NADH-quinone reductase (NQR) from the marine Vibrio alginolyticus is composed of six structural genes (nqrA to nqrF). The NqrF subunit has non-covalently bound FAD. There are conflicting results on the existence of other flavin cofactors. Recent studies revealed that the NqrB and NqrC subunits have a covalently bound flavin, possibly FMN, which is attached to a specified threonine residue. A novel antibiotic, korormicin, was found to specifically inhibit the NQR complex. From the homology search of the nqr operon, it was found that the Na(+)-pumping NQR complex is widely distributed among Gram-negative pathogenic bacteria.     

Comparative analysis of antibiotic sensitivity of Streptococcus pneumoniae strains isolated from patients and carriers

The data on antibiotic sensitivity of 38 strains of S. pneumoniae isolated from children and 46 strains isolated from carriers are presented. The isolates from the carriers had significantly higher sensitivity to benzylpenicillin, ampicillin, methicillin, oxacillin, cefazolin, erythromycin, oleandomycin and lincomycin. Resistance to gentamicin was more frequent in the strains isolated from the carriers. Among the strains of S. pneumoniae isolated from the patients and carriers representatives of serovar K19 were more frequent. There were no statistically reliable difference in them by sensitivity to benzylpenicillin, ampicillin, cefazolin, lincomycin and rifampicin. Still, the isolates from the carriers were much more sensitive to methicillin, oxacillin, oleandomycin and erythromycin.     

四株杂交鳢致病性舒伯特气单胞菌特性及致病性比较

【背景】舒伯特气单胞菌为革兰氏阴性短杆菌,是一种人-畜-鱼共患的条件性致病菌,它能引起不同程度的人类疾病,近年来更是在水产养殖中被频繁报道。【目的】比较分析4株杂交鳢源舒伯特气单胞菌(WL-4、ZL-1、ZL-13、D075)菌株间生理生化特性、致病性以及对常用药物的敏感性差异,为水产舒伯特气单胞菌病的防治提供参考依据。【方法】使用全自动细菌生化鉴定仪检测菌株的生理生化特性;运用PCR扩增和测序比对菌株的gyrB、16S rRNA基因序列;采用改良平板法检测毒力因子表达,PCR技术检测菌株毒力基因和耐药基因的携带情况;通过人工注射感染分析4株舒伯特气单胞菌对杂交鳢的致病性差异;并采用微量二倍稀释法测试15种抗菌药物对菌株的最小抑菌浓度。【结果】以ATCC43700 (人源舒伯特气单胞菌)作为参考,4株菌株理化特性基本相同,gyrB和16SrRNA基因一致性分别为99.57%和100%,聚类分析聚为一簇;不同的舒伯特气单胞菌(ATCC43700、WL-4、ZL-1、ZL-13、D075)均具有溶血性、蛋白酶活性和脂肪酶活性;但人源菌株(ATCC43700)与杂交鳢源舒伯特气单胞菌携带的毒力基因存在差异,其中人源菌株携带了hlyA、ela、lip、ahal、act,而杂交鳢源菌株(WL-4、ZL-1、ZL-13、D075)携带hlyA、ela、lip、ahal、aer;4株杂交鳢源舒伯特气单胞菌对杂交鳢致病性存在差异,1.2×10~5CFU/mL浓度腹腔注射感染健康杂交鳢,WL-4、ZL-1、ZL-13、D075对杂交鳢的感染致死率依次为30%、40%、70%和80%;不同菌株(ATCC43700、WL-4、ZL-1、ZL-13、D075)的药物敏感性以及携带的耐药基因也存在差异。【结论】4株杂交鳢源舒伯特气单胞菌在致病性、药物敏感性等方面存在差异,研究结果有助于进一步开展舒伯特气单胞菌病发病机制和防控技术研究。     

Pathogenicity of Vibrio alginolyticus isolated from diseased small abalone Haliotis diversicolor supertexta

Outbreaks of mass mortality among cultured small abalone Haliotis diversicolor supertexta with abscess/ulcers in the mantle occurred in 1998 at Kao-Hsiung, Taiwan. A swarming bacterium, strain H-11 was isolated from the haemolymph of the moribund small abalone using tryptic soy agar supplemented with 3% NaCl and/or thiosulphate citrate bile salt sucrose agar. This strain was characterized and identified as Vibrio alginolyticus on the basis of various biochemical tests. The H-11 strain and its extracellular products were virulent to small abalones with LD50 values of 3.6 x 10(5) colony forming units and 2.96 microg protein/g body weight, respectively.     

Investigation of seven Vibrio virulence genes among Vibrio alginolyticus and Vibrio parahaemolyticus strains from the coastal mariculture systems in Guangdong, China

AIMS: To investigate the distribution of the virulence of two Vibrio species among different strains obtained from the mariculture systems on the coast of Guangdong in China and the correlation between the virulence strains and the virulence genes among Vibrio alginolyticus. METHODS: Besides three strains, 72 V. alginolyticus strains and seven Vibrio parahaemolyticus strains were examined by PCR or semi-nested PCR for the virulence genes (tlh, trh, tdh, toxR, toxRS, ctxA, VPI). Additionally, the virulence of 18 V. alginolyticus strains was tested. SIGNIFICANCE AND IMPACT OF THE STUDY: Virulence genes homologous to those in the V. parahaemolyticus and Vibrio cholerae are widely distributed among V. alginolyticus and V. parahaemolyticus in the coastal mariculture systems in Guangdong, China. Some of the V. alginolyticus strains are pathogenic to aquatic animals, and might have derived their virulence genes from V. parahaemolyticus or V. cholerae, representing a possible reservoir of these genes. However, there is no correlation between presence and absence of the virulence genes used to investigate V. alginolyticus and its virulent strains. In this report, we also show that tlh is distributed among V. alginolyticus.     

Cellular fatty acid profiles of ninety-five strains of Vibrio vulnificus isolated from clinical specimens in Korea

There have been many reports of primary Vibrio vulnificus septicemia in Korea since 1987. This study was undertaken to determine the cellular fatty acid (CFA) compositions of 95 clinical strains of V. vulnificus isolated in Korea during 1985-1995. We compared these results with the CFA profile of V. vulnificus in the Microbial Identification System (MIS) (CLIN library version 3.9; Microbial ID Inc., Newark, DE, U.S.A.), and the grouping of V. vulnificus by CFA analysis was also performed. The relationship between groups and serotypes of V. vulnificus was described. Although most of the CFAs in V. vulnificus strains were similar to the CFA profile of V. vulnificus in the MIS, some distinctive differences were observed between the results of this study and the MIS CFA profile of V. vulnificus. First, the means of 2 major CFAs, 16 : 0 and 16 : 1w7c, were 22.16 and 18.26% in this study but 23.52 and 25.44% in the MIS, respectively. Second, all isolates had 11 : 0iso3OH, which was not present in the MIS. Of 95 strains, 10 strains (10.5%) showed 'NO MATCH' results by the MIS identification. Eighty five strains (89.5%) were identified as V. vulnificus by the MIS (the first choice identification), but they disclosed low SI values of <0.6 (not 'EXCELLENT MATCH') except 2 strains (2.1%). This showed that V. vulnificus strains isolated in Korea had different characteristics in CFA composition in comparison with the MIS V. vulnificus library. Nine groups comprising all the strains were obtained by cluster analysis and were further characterized by principal-component analysis. There was heterogeneity between the groups by CFA and serotypes of V. vulnificus. The same serovars were distributed into diverse groups.     

Molecular characterisation and antimicrobial resistance of Vibrio vulnificus and Vibrio alginolyticus isolated from mussels (Mytilus galloprovincialis)

Twelve Vibrio vulnificus biotype 1 and 11 Vibrio alginolyticus isolated from mussels in Italy were analysed by antimicrobial resistance, plasmid profiles, random amplification of polymorphic DNA (RAPD), and single enzyme amplified fragment length polymorphism (sAFLP). Plasmid DNA was detected in three V. vulnificus and four V. alginolyticus cultures. All isolates were resistant to at least two antimicrobial agents: all isolates were resistant to ampicillin, carbenicillin and streptomycin, except one V. alginolyticus which was sensitive to carbenicillin and two V. alginolyticus which were sensitive to streptomycin. No association was detected between the presence of plasmid DNA and antimicrobial resistance. Seven of the twelve V. vulnificus and two of the eleven V. alginolyticus cultures were susceptible to the 10 microg of the vibriostatic compound O/129; all cultures were susceptible to the 150 microg of O/129. Both RAPD and sAFLP was found to be reproducible. Ten sAFLP and seven RAPD profiles were detected amongst the 12 V. vulnificus cultures: three cultures were identified as indistinguishable by both methods. RAPD and sAFLP analysis of V. alginolyticus generated nine and seven profiles respectively, and these two methods were independent. These results demonstrate extreme variability of V. vulnificus and V. alginolyticus isolated from mussels, and both RAPD and sAFLP provided information on intraspecific differences which will be useful for molecular epidemiological or ecological studies. A combination of methods gave optimal discrimination, although a single method could provide sufficient information to characterise V. vulnificus isolates.     

Virulence of Vibrio vulnificus strains from marine environments.

Vibrio vulnificus strains isolated from geographically diverse marine sources were compared with clinical isolates for phenotype and in vitro and in vivo production of virulence factors. There were no differences between environmental and clinical strains on the basis of biochemical characteristics or antimicrobial susceptibility patterns. Cytolysin and cytotoxin titers produced by environmental strains were generally comparable to those of clinical strains. Of 29 environmental isolates tested, 25 were pathogenic for mice. These data show that environmental V. vulnificus strains are phenotypically indistinguishable from clinical isolates and that approximately 90% of the environmental strains tested produced in vitro virulence factors and in vivo pathogenicity for mice comparable to those produced by clinical V. vulnificus isolates.