选择性富集沙门氏菌、副溶血弧菌和霍乱弧菌的共增菌培养基SVV

本研究通过单因素试验和响应面分析试验建立了能够选择性富集沙门氏菌、副溶血弧菌和霍乱弧菌的共增菌培养基SVV,采用平板计数法及三重荧光PCR技术验证了SVV的增菌效果。结果表明:SVV能同时富集以不同浓度比例混合的3种目标菌,37oC振荡培养18h后,菌体浓度达到105~108CFU/mL;SVV强烈抑制大部分的非目标菌;用荧光PCR方法检测经过37oC振荡培养18h的10份人工接种样品和608份实际样品,结果表明目标菌在SVV中增殖18h后菌量达到检测限以上,SVV联合荧光PCR检测方法的检出率为4.06%,比传统检测方法(3.78%)高,无假阴性和假阳性。SVV可望应用于水产品中沙门氏菌、副溶血弧菌和霍乱弧菌检测前的增菌处理,可简化检测过程,有效克服漏检,提高检出率。     

Incidence of Salmonella spp., Clostridium botulinum, and Vibrio parahaemolyticus in an estuary.

A study of the incidence of Salmonella spp., Vibrio parahaemolyticus-like organisms, and clostridium botulinum in samples collected at five stations located in the Upper Chesapeake Bay, a major estuary on the Atlantic Coast of the United States, was conducted in December 1973 through December 1974. C. botulinum types B and E were detected in 12.3% of the total sediment samples examined. V. parahaemolyticus was recovered from 10.4% of a total of 86 water, sediment, and suspended sediment samples. Of 131 samples examined for the presence of Salmonella spp., approximately 3% were found to be positive for serologically confirmed Salmonella isolates. Shellfish examined during the investigation were also found to be free of enteric pathogens. The low frequency of occurrence of V. parahaemolyticus was attributed to the low salinities encountered at the sites included in the study. A low incidence of Salmonella spp. in the Upper Chesapeake Bay samples was found, whereas the distribution of C. botulinum appeared to be both random and autochthonous. A strong relationship between presence of potential pathogens and other generally accepted microbiological indicators of pollution was not observed.     

Ecology of Vibrio cholerae non-O1 and Salmonella spp. and role of zooplankton in their seasonal distribution in Fukuyama coastal waters, Japan

Seasonal variation of human pathogens such as Vibrio Cholerae non-01 and Salmonella spp. in Fukuyama coastal waters and the role of zooplankton in their distribution were studies for a period of 1 year. Comparison of two established methods, viz., the elevated temperature method and the two-step enrichment method of enumerating V. cholerae, showed that the former is superior in the recoveries of V. cholerae non-01. Isolation of this pathogen on a wider range of salinities (0.4 to 32.5%) revealed that these organisms are apparently an autochthonous component of the aquatic environment. Temperature appears to be the most crucial element in governing the distribution of V. cholerae non-01. Among the 69 isolates serotyped, 22 different serovars were identified, while one isolate failed to react with any of the known Louisiana State University antisera tested. Zooplankton samples did not harbor more V. Cholerae non-01 than the water column did. Better isolation of an allochthonous pathogen, viz., Salmonella spp., was noticed from the water samples when swabs were employed. Of the 251 isolates serotyped, 18 serotypes with three variants of Salmonella spp. were identified. A high amount of nutrients in the water column increased the survival rate of these pathogens in saline waters as evidenced by a higher incidence of various serotypes in polluted Fukuyama port than in clean marine waters. Salmonella spp. association between V. cholerae non-01 of Salmonella spp. with zooplankton could be noticed as influencing their seasonal distribution.     

Ecology of Vibrio cholerae non-O1 and Salmonella spp. and role of zooplankton in their seasonal distribution in Fukuyama coastal waters, Japan.

Seasonal variation of human pathogens such as Vibrio Cholerae non-01 and Salmonella spp. in Fukuyama coastal waters and the role of zooplankton in their distribution were studies for a period of 1 year. Comparison of two established methods, viz., the elevated temperature method and the two-step enrichment method of enumerating V. cholerae, showed that the former is superior in the recoveries of V. cholerae non-01. Isolation of this pathogen on a wider range of salinities (0.4 to 32.5%) revealed that these organisms are apparently an autochthonous component of the aquatic environment. Temperature appears to be the most crucial element in governing the distribution of V. cholerae non-01. Among the 69 isolates serotyped, 22 different serovars were identified, while one isolate failed to react with any of the known Louisiana State University antisera tested. Zooplankton samples did not harbor more V. Cholerae non-01 than the water column did. Better isolation of an allochthonous pathogen, viz., Salmonella spp., was noticed from the water samples when swabs were employed. Of the 251 isolates serotyped, 18 serotypes with three variants of Salmonella spp. were identified. A high amount of nutrients in the water column increased the survival rate of these pathogens in saline waters as evidenced by a higher incidence of various serotypes in polluted Fukuyama port than in clean marine waters. Salmonella spp. association between V. cholerae non-01 of Salmonella spp. with zooplankton could be noticed as influencing their seasonal distribution.     

Growth response of Vibrio cholerae and other Vibrio spp. to cyanobacterial dissolved organic matter and temperature in brackish water

Environmental control of growth and persistence of vibrios in aquatic environments is poorly understood even though members of the genus Vibrio are globally important pathogens. To study how algal-derived organic matter and temperature influenced the abundance of different Vibrio spp., Baltic Sea microcosms inoculated with Vibrio cholerae, Vibrio vulnificus, Vibrio parahaemolyticus, Vibrio alginolyticus and native bacterioplankton, were exposed to different temperatures (12-25 degrees C) and amended with dissolved organic matter from Nodularia spumigena (0-4.2 mg C L(-1)). Vibrio abundance was monitored by culture-dependent and molecular methods. Results suggested that Vibrio populations entered a viable but nonculturable state during the incubations. Abundance of Vibrio spp. and total bacterioplankton were orders of magnitude higher in microcosms amended with organic matter compared with reference microcosms. Vibrio cholerae abundances ranged from 0.9 to 1.9 x 10(5) cells mL(-1) in treatments amended with 4.2 mg C L(-1). Vibrio cholerae abundance relative to total bacterioplankton and other Vibrio spp. also increased >10-fold. In addition, V. vulnificus abundance increased in mesocosms with the highest organic matter addition (0.9-1.8 x 10(4) cells mL(-1)). Temperature alone did not significantly affect abundances of total bacterioplankton, total Vibrio spp. or individual Vibrio populations. By contrast, cyanobacterial-derived organic matter represented an important factor regulating growth and abundance of V. cholerae and V. vulnificus in brackish waters.     

A universal protocol for PCR detection of 13 species of foodborne pathogens in foods

A universal protocol for PCR detection of 13 species of foodborne pathogens in foods wasdeveloped. The protocol used a universal culture medium and the same PCR conditions with 13sets of specific primers. The 13 species of foodborne pathogens examined were Escherichiacoli, E. coli- ETEC, E. coli -O157:H7, Shigella spp. , Salmonella spp. , Yersinia enterocolitica, Y. pseudotuberculosis, Vibrio cholerae, V.parahaemolyticus, V. vulnificus , Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus . No interference was observed using the PCR assay when foodsample was artificially inoculated with each individual bacterial species. Twelve different seafoodsamples and two soft cheese samples without artificial inoculation were examined by thisprotocol. Vibrio vulnificus, Salmonella spp. , E. coli,Listeria monocytogenes and Bacillus cereus were detected in some foods.Internal probe hybridization and nested PCR procedures were used to confirm the above findings.     

Detection of pathogenic Vibrio spp. in shellfish by using multiplex PCR and DNA microarrays

This study describes the development of a gene-specific DNA microarray coupled with multiplex PCR for the comprehensive detection of pathogenic vibrios that are natural inhabitants of warm coastal waters and shellfish. Multiplex PCR with vvh and viuB for Vibrio vulnificus, with ompU, toxR, tcpI, and hlyA for V. cholerae, and with tlh, tdh, trh, and open reading frame 8 for V. parahaemolyticus helped to ensure that total and pathogenic strains, including subtypes of the three Vibrio spp., could be detected and discriminated. For DNA microarrays, oligonucleotide probes for these targeted genes were deposited onto epoxysilane-derivatized, 12-well, Teflon-masked slides by using a MicroGrid II arrayer. Amplified PCR products were hybridized to arrays at 50 degrees C and detected by using tyramide signal amplification with Alexa Fluor 546 fluorescent dye. Slides were imaged by using an arrayWoRx scanner. The detection sensitivity for pure cultures without enrichment was 10(2) to 10(3) CFU/ml, and the specificity was 100%. However, 5 h of sample enrichment followed by DNA extraction with Instagene matrix and multiplex PCR with microarray hybridization resulted in the detection of 1 CFU in 1 g of oyster tissue homogenate. Thus, enrichment of the bacterial pathogens permitted higher sensitivity in compliance with the Interstate Shellfish Sanitation Conference guideline. Application of the DNA microarray methodology to natural oysters revealed the presence of V. vulnificus (100%) and V. parahaemolyticus (83%). However, V. cholerae was not detected in natural oysters. An assay involving a combination of multiplex PCR and DNA microarray hybridization would help to ensure rapid and accurate detection of pathogenic vibrios in shellfish, thereby improving the microbiological safety of shellfish for consumers.     

Epidemiology and potential land-sea transfer of enteric bacteria from terrestrial to marine species in the Monterey Bay Region of California

Marine mammals are at risk for infection by fecal-associated zoonotic pathogens when they swim and feed in polluted nearshore marine waters. Because of their tendency to consume 25-30% of their body weight per day in coastal filter-feeding invertebrates, southern sea otters (Enhydra lutris nereis) can act as sentinels of marine ecosystem health in California. Feces from domestic and wildlife species were tested to determine prevalence, potential virulence, and diversity of selected opportunistic enteric bacterial pathogens in the Monterey Bay region. We hypothesized that if sea otters are sentinels of coastal health, and fecal pollution flows from land to sea, then sea otters and terrestrial animals might share the same enteric bacterial species and strains. Twenty-eight percent of fecal samples tested during 2007-2010 were positive for one or more potential pathogens. Campylobacter spp. were isolated most frequently, with an overall prevalence of 11%, followed by Vibrio cholerae (9%), Salmonella spp. (6%), V. parahaemolyticus (5%), and V. alginolyticus (3%). Sea otters were found positive for all target bacteria, exhibiting similar prevalences for Campylobacter and Salmonella spp. but greater prevalences for Vibrio spp. when compared to terrestrial animals. Fifteen Salmonella serotypes were detected, 11 of which were isolated from opossums. This is the first report of sea otter infection by S. enterica Heidelberg, a serotype also associated with human clinical disease. Similar strains of S. enterica Typhimurium were identified in otters, opossums, and gulls, suggesting the possibility of land-sea transfer of enteric bacterial pathogens from terrestrial sources to sea otters.     

A novel multiplex PCR for the identification of Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus

AIM: To establish a simple multiplex polymerase chain reaction (PCR) that will identify Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus. METHODS AND RESULTS: A total of 429 Vibrio spp. from various origins were tested with the novel primers targeting toxR. The reverse primers were all designed to be species specific, while the forward primer was universal. The primers correctly identified all the V. parahaemolyticus, V. cholerae and V. vulnificus isolates tested. CONCLUSIONS: The toxR multiplex PCR works well when the initial colony morphology is known. If not, Vibrio alginolyticus might represent a diagnostic obstacle. SIGNIFICANCE AND IMPACT OF THE STUDY: The method provides a fast and reliable way of identifying the main Vibrio spp. involved in food-borne disease. The method could prove very useful for laboratories working with identification of these Vibrio spp.     

PCR detection of a newly emerged pandemic Vibrio parahaemolyticus O3:K6 pathogen in pure cultures and seeded waters from the Gulf of Mexico

This study describes the optimization of PCR parameters and testing of a wide number of microbial species to establish a highly specific and sensitive PCR-based method of detection of a newly emerged pandemic Vibrio parahaemolyticus O3:K6 strain in pure cultures and seeded waters from the Gulf of Mexico (gulf water). The selected open reading frame 8 (ORF8) DNA-specific oligonucleotide primers tested were found to specifically amplify all 35 pathogenic V. parahaemolyticus O3:K6 pandemic isolates, whereas these primers were not found to detectably amplify two strains of V. parahaemolyticus O3:K6 that were isolated prior to the 1996 outbreaks, 122 non-O3:K6 strains of V. parahaemolyticus, 198 non-V. parahaemolyticus spp., or 16 non-Vibrio bacterial spp. The minimum level of detection by the PCR method was 1 pg of purified genomic DNA or 10(2) ORF8-positive V. parahaemolyticus O3:K6 cells in 100 ml of water. The effectiveness of this method for the detection of ORF8-positive isolates in environmental samples was tested in gulf water seeded with 10-fold serial dilutions of this pathogen. A detection level of 10(3) cells per 100 ml of gulf water was achieved. Also, the applicability of this methodology was tested by the detection of this pathogen in gulf water incubated at various temperatures for 28 days. This PCR approach can potentially be used to monitor with high specificity and well within the required range of sensitivity the occurrence and distribution of this newly emerged pathogenic V. parahaemolyticus O3:K6 strain in coastal, marine, and ship ballast waters. Early detection of V. parahaemolyticus O3:K6 will help increase seafood safety and decrease the risk of infectious outbreaks caused by this pathogen.     

Development and evaluation of two novel oligonucleotide probes based on 16S rRNA sequence for the identification of Salmonella in foods

DNA sequence in the V3 to V6 region of the 16S rRNA gene of Salmonella enteritidis was determined. By comparison of this sequence with those of Escherichia coli and Proteus vulgaris obtained from GenBank/EMBL database, three oligonucleotides termed as 16S I, 16S II and 16S III were synthesized. Hybridization of these oligonucleotides with 325 Salmonella isolates and some non- Salmonella isolates including the Salmonella closely related species of the family of Enterobacteriaceae showed that 16S II could not be used as a Salmonella specific-probe. 16S I and 16S III hybridized with all the Salmonella isolates tested, the former also hybridizing with Citrobacter spp. and the latter hybridizing with Klebsiella pneumoniae as well as Serratia marcescens. Since enrichment of the target cells in food samples was usually required prior to the DNA hybridization assay, the interference from those non- Salmonella isolates could be prevented by enrichment by culturing in lactose-combined tetrathionate (CTET) broth followed by Gram-negative (GN) broth at 37°C and/or 43°C. Such a culture step could inhibit the growth of Klebsiella spp., Ser. marcescens and/or Citrobacter spp. and allowed the specific detection of Salmonella .     

Sequence of a cloned pR72H fragment and its use for detection of Vibrio parahaemolyticus in shellfish with the PCR.

The nucleotide sequence of pR72H cloned from Vibrio parahaemolyticus 93 was determined. We examined all V. parahaemolyticus gene sequences published in the GenBank-EMBL databases for homology and found that no other DNA sequence of V. parahaemolyticus was highly homologous to the sequence reported in this study. A pair of primers, VP33-VP32, derived from a pR72H fragment were selected to detect V. parahaemolyticus. The sensitivity of PCR detection for a pure culture of V. parahaemolyticus was 10 cells from crude bacterial lysates. Furthermore, a detection level of 2.6 fg, equivalent to 1 cell, was obtained by using purified chromosomal DNA as the template. The expected PCR products were obtained from all V. parahaemolyticus strains tested (n = 124), while no PCR amplicons were found in other vibrios or related genera (n = 50). High levels (10(6) to 10(10) CFU/ml) of Escherichia coli cells did not affect the PCR assay sensitivity. The presence of 10(8) V. parahaemolyticus cells or 10(9) E. coli cells in the PCR mixtures completely inhibited the PCR. When oyster samples were inoculated with V. parahaemolyticus 93 and cultured in tryptic soy broth containing 3% NaCl for 3 h at 35 degrees C, an initial sample inoculum level of 9.3 CFU/g was detected in a PCR assay with crude bacterial lysates. The PCR assay with enrichment culturing in salt polymyxin broth was compared with the conventional method for naturally contaminated shellfish and fish samples. We conclude that this PCR assay with enrichment culturing is a good alternative method for the detection of V. parahaemolyticus.     

Incidence of Vibrio species associated with blue crabs (Callinectes sapidus) collected from Galveston Bay, Texas.

Bacteria were readily isolated from the hemolymph of a majority (88%) of the blue crabs collected from Galveston Bay, Texas. The hemolymph of most crabs contained moderate (greater than 10(3) bacteria/ml) to heavy (greater than (10(5) bacteria/ml) infections. Large variances were observed in the bacterial number associated with individual crabs, but no significant difference was observed between the mean bacterial levels in the hemolymph of crabs collected during different seasons of the sampling year. Vibrio spp. were the predominant bacterial types in the hemolymph of infected crabs and increased in number significantly during the summer season. Warmer water temperatures were thought to be responsible for this increase. Bacterial numbers and the percentage of Vibrio spp. were highest in the interior of the crab bodies, especially in the digestive tract. The exterior of the crabs did not appear to be the source of the hemolymph's bacterial flora. Bacteria taxonomically identical to Vibrio cholerae. V. vulnificus, and V. parahaemolyticus were routinely isolated from the crab hemolymph and external carapace. V. parahaemolyticus was the most prevalent of the pathogenic Vibrio spp. and was isolated from 23% of the hemolymph samples. V. vulnificus (7%) and V. cholerae (2%) occurred less commonly in the hemolymph. The incidences of V. parachaemolyticus and V. vulnificus were related and increased in the summer months. Both organisms were frequently isolated from the same crab.     

Occurrence and potential pathogenesis of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus on the South Coast of Sweden

During the summer of 2006, several wound infections - of which three were fatal - caused by Vibrio cholerae were reported from patients who had been exposed to water from the Baltic Sea. Before these reports, we initiated a sampling project investigating the occurrence of potential human pathogenic V. cholerae, Vibrio vulnificus and Vibrio parahaemolyticus in The Sound between Sweden and Denmark. The Blue mussel (Mytilus edulis) was used as an indicator to follow the occurrence of vibrios over time. Molecular analyses showed high frequencies of the most potent human pathogenic Vibrio spp.; 53% of mussel samples were positive for V. cholerae (although none were positive for the cholera toxin gene), 63% for V. vulnificus and 79% for V. parahaemolyticus (of which 47% were tdh(+) and/or trh(+)). Viable vibrios were also isolated from the mussel meat and screened for virulence by PCR. The mortality of eukaryotic cells when exposed to bacteria was tested in vivo, with results showing that the Vibrio strains, independent of species and origin, were harmful to the cells. Despite severe infections and several deaths, no report on potential human pathogenic vibrios in this area had been published before this study.     

Detection of Vibrio cholerae by real-time nucleic acid sequence-based amplification

A multitarget molecular beacon-based real-time nucleic acid sequence-based amplification (NASBA) assay for the specific detection of Vibrio cholerae has been developed. The genes encoding the cholera toxin (ctxA), the toxin-coregulated pilus (tcpA; colonization factor), the ctxA toxin regulator (toxR), hemolysin (hlyA), and the 60-kDa chaperonin product (groEL) were selected as target sequences for detection. The beacons for the five different genetic targets were evaluated by serial dilution of RNA from V. cholerae cells. RNase treatment of the nucleic acids eliminated all NASBA, whereas DNase treatment had no effect, showing that RNA and not DNA was amplified. The specificity of the assay was investigated by testing several isolates of V. cholerae, other Vibrio species, and Bacillus cereus, Salmonella enterica, and Escherichia coli strains. The toxR, groEL, and hlyA beacons identified all V. cholerae isolates, whereas the ctxA and tcpA beacons identified the O1 toxigenic clinical isolates. The NASBA assay detected V. cholerae at 50 CFU/ml by using the general marker groEL and tcpA that specifically indicates toxigenic strains. A correlation between cell viability and NASBA was demonstrated for the ctxA, toxR, and hlyA targets. RNA isolated from different environmental water samples spiked with V. cholerae was specifically detected by NASBA. These results indicate that NASBA can be used in the rapid detection of V. cholerae from various environmental water samples. This method has a strong potential for detecting toxigenic strains by using the tcpA and ctxA markers. The entire assay including RNA extraction and NASBA was completed within 3 h.     

Effect of Mg(2+) ion in protein secretion by magnesium-resistant strains of Pseudomonas aeruginosa and Vibrio parahaemolyticus isolated from the coastal water of Haldia port

A rapidly growing industrial complex including oil refineries and chemical industries has developed around the coastal area of Haldia port in the district of Midnapore, West Bengal, India. The coastal water is highly polluted with industrial wastes along with petroleum hydrocarbons. The bacteria isolated from the different sites of the coastal waters were Escherichia coli, Alcaligenes, Acinetobacter, Klebsiella spp., Micrococcus spp., Vibrio spp., Pseudomonas aeruginosa and Vibrio parahaemolyticus. The salinity of the water during the time of collection of samples around the port area was 8. 2 ppt. Among the isolated organisms, only two isolates, P. aeruginosa and V. parahaemolyticus, showed growth at 300 mM Mg(2+) ion concentration. However, a 3 mM Mg(2+) concentration was detected in the coastal water whereas other metal ion concentrations were less than 3x10(-5) mM. Resistance to Mg(2+) (300 mM) was determined by a 5.5-kb plasmid. A large amount of a 40-kDa outer membrane protein, which was highly soluble in 1 M MgCl(2), was isolated from both V. parahaemolyticus and P. aeruginosa. The secretion of proteins in the culture supernatant of V. parahaemolyticus was highly increased when the cells were grown in the presence of 300 mM Mg(2+), whereas very low secretion was observed in the same concentration of Mg(2+) in the case of P. aeruginosa. Mg(2+) may act as a specific release factor in protein secretion by V. parahaemolyticus strains.     

Direct immunofluorescence assay for rapid environmental detection ofVibrio cholerae O1

An immunofluorescence assay for direct detection of V. cholerae O1 was developed using polyclonal antibodies raised against outer membrane proteins (OMPs) of V. cholerae O1. Production of OMPs varied with growth media used; maximum production was found in tryptic soy broth. The detection system was specific because no cross-reactivity was observed with other bacteria including V. cholerae O139, E. coli, S. dysenteriae and Salmonella enterica subsp. enterica serovar Typhi. The technique was able to detect 240 CFU/mL of V. cholerae O1 suspended in phosphate-buffered saline. The assay coupled with bacterial enrichment in APW for 6 h detected as few as 5 CFU of V. cholerae in spiked samples. Moreover, a 2-h incubation of enriched bacterial cells in 0.1% yeast extract with 10 ppm nalidixic acid enhanced the bacterial size and helped in morphological identification of V. cholerae. Among 32 potable water samples from afflicted hand pumps and wells collected from a cholera-plagued area 12 were found to be contaminated with V. cholerae by immunofluorescence assay as well as by conventional culture methods. The proposed method could thus be employed in environmental surveillance of V. cholerae O1.     

Improved method for detection of Vibrio parahaemolyticus in seafood.

We have developed a new, effective procedure for detecting Vibrio parahaemolyticus in seafoods using enrichment and plating onto a chromogenic agar medium. Samples were cultured in salt Trypticase soy broth, which is a nonselective medium, and then a portion of the culture was cultured with salt polymyxin broth, which is a selective medium for V. parahaemolyticus. This two-step enrichment was more effective than the one-step enrichment in salt polymyxin broth alone. The enrichment cultures were then plated onto a new chromogenic agar containing substrates for beta-galactosidase. The V. parahaemolyticus colonies developed a purple color on this growth medium that distinguished them from other related bacterial strains. V. parahaemolyticus was isolated more frequently from naturally contaminated seafood samples using the chromogenic agar than thiosulfate citrate bile salts sucrose agar medium, which is currently used for the isolation of V. parahaemolyticus. Our findings suggest that this new enrichment and isolation scheme is more sensitive and accurate for identifying V. parahaemolyticus in seafood samples than previously used methods.     

一种能同时富集沙门氏菌、金黄色葡萄球菌和单增李斯特菌的培乔基

[目的]设计制备一种能够同时富集沙门氏菌、金黄色葡萄球菌及单增李斯特菌的复合增菌肉汤.[方法]挑选合适的添加剂进行单因素实验,确定增菌肉汤的成分及配比,采用平板计数法及三重荧光PCR技术验证肉汤的增菌效果.[结果]结果得到一种能同时富集沙门氏菌、金黄色葡萄球菌及单增李斯特菌的选择性增菌肉汤(SSL),经验证SSL可使得3种目标菌以相对一致的速度进行富集,经过37℃ 150 r/min振荡培养24 h后,菌体浓度到达10~7～10~8 CFU/mL,非目标菌生长受到抑制.应用荧光PCR扩增样品,可同时得到3种目标菌的扩增曲线.在710份实际样品检测中,无假阳性及假阴性报告.[结论]研究结果表明,SSL肉汤可用于沙门氏菌、金黄色葡萄球菌及单增李斯特菌的共增菌,可用于多重PCR检测的前增菌.     

Catecholamine-induced stimulation of growth in Vibrio species

AIMS: To evaluate the effect of norepinephrine (NE) and related compounds on the growth of bacteria, we have examined the effect of the neuroendocrine hormone NE and related compounds on the growth of Vibrio parahaemolyticus and other human-pathogenic Vibrio species (Vibrio cholerae, Vibrio vulnificus, and Vibrio mimicus). METHODS AND RESULTS: The effects on bacterial growth were examined using the serum-based medium and viable cells were counted using agar plates. We have shown that NE and its related compounds stimulate growth of V. parahaemolyticus in serum-based medium. This NE-induced growth stimulation was dependent upon the presence of transferrin. NE also stimulated growth of V. mimicus, but not V. cholerae and V. vulnificus. CONCLUSIONS: These results suggest that the Vibrio species differ in their ability to respond to NE. SIGNIFICANCE AND IMPACT OF THE STUDY: It is possible that NE and related compounds modulate the pathogenicity of V. parahaemolyticus and V. mimicus.