1例白血病患者血液中检出非O1非O139群霍乱弧菌

2012年8月,浦东新区儿童医学中心从1名6岁急性淋巴细胞性白血病复发患儿血液中分离到霍乱弧菌,随后浦东新区疾病预防控制中心对该分离株进行了系统生化鉴定、毒力基因及药物敏感性检测,结果为不产霍乱毒素的非O1非O139霍乱弧菌。     

Vibrio cholerae (non-O1, non-O139) sepsis in a child with Fanconi anemia

A 9-year-old female child who was a known case of Fanconi anemia was admitted to hospital because of fever and gastrointestinal symptoms. Blood culture at the time of admission yielded growth of Gram-negative curved rod that was identified as Vibrio cholerae (non-O1, non-O139), whereas repeated fecal cultures were negative for enteropathogens. To our knowledge, this is the first case of V. cholerae (non-O1, non-O139) septicemia associated with Fanconi anemia.     

O1 and non-O1 Vibrio cholerae bacteremia produced by hemolytic strains

Vibrio cholerae are Gram-negative bacteria capable of producing serious infections. They are differentiated into O1 and non-O1 serogroups, depending on their ability to agglutinate with specific antiserum. In contrast to non-O1 V. cholerae, which are more prone to invading the bloodstream, V. cholerae O1 is rarely the cause of bacteremia. We describe 2 cases of O and non-O1 V. cholerae bacteremia in patients with hepatitis C virus cirrhosis. We postulate that the hemolytic properties of the isolates contributed to their virulence in immunocompromised hosts.     

Spontaneous bacterial empyema due to non-O1, non-O139 Vibrio cholerae in a cirrhotic patient with hepatocellular carcinoma

Vibrio cholerae is known as a common etiology of epidemic diarrheal disease and rarely causes extra-intestinal infections. In this report, we described a cirrhotic patient with hepatocellular carcinoma who developed spontaneous bacterial empyema due to non-O1, non-O139 V. cholerae. The patient was successfully treated with antimicrobial agents and percutaneous drainage.     

Fatalities associated with Vibrio parahaemolyticus and Vibrio cholerae non-O1 infections in Florida (1981 to 1988)

Vibrio infections constitute a continuing source of morbidity and mortality in Florida. Seven fatal infections caused by Vibrio parahaemolyticus or V cholerae non-O1 were reported in Florida between 1981 and 1988. Review of those seven medical records and Vibrio case investigation forms showed that although all patients died of sepsis, gastrointestinal signs and symptoms characterized the early illness in four patients, whereas the other three initially had painful swelling and/or lesions of the lower extremities. All patients had preexisting chronic diseases. Five patients (71%) had eaten seafood during the week before oneset of illness, including four (57%) who had eaten raw oysters. To reduce the risk of acquiring Vibrio infections, raw or undercooked seafood should be eliminated from the diet, particularly by persons with underlying chronic diseases.     

New carbenicillin-hydrolyzing beta-lactamase (CARB-7) from Vibrio cholerae non-O1, non-O139 strains encoded by the VCR region of the V. cholerae genome

In a previous study, an analysis of 77 ampicillin-nonsusceptible (resistant plus intermediate categories) strains of Vibrio cholerae non-O1, non-O139, isolated from aquatic environment and diarrheal stool, showed that all of them produced a beta-lactamase with a pI of 5.4. Hybridization or amplification by PCR with a probe for bla(TEM) or primers for bla(CARB) gene families was negative. In this work, an environmental ampicillin-resistant strain from this sample, ME11762, isolated from a waterway in the west region of Argentina, was studied. The nucleotide sequence of the structural gene of the beta-lactamase was determined by bidirectional sequencing of a Sau3AI fragment belonging to this isolate. The gene encodes a new 288-amino-acid protein, designated CARB-7, that shares 88.5% homology with the CARB-6 enzyme; an overall 83.2% homology with PSE-4, PSE-1, CARB-3, and the Proteus mirabilis N29 enzymes; and 79% homology with CARB-4 enzyme. The gene for this beta-lactamase could not be transferred to Escherichia coli by conjugation. The nucleotide sequence of the flanking regions of the bla(CARB-7) gene showed the occurrence of three 123-bp V. cholerae repeated sequences, all of which were found outside the predicted open reading frame. The upstream fragment of the bla(CARB-7) gene shared 93% identity with a locus situated inside V. cholerae's chromosome 2. These results strongly suggest the chromosomal location of the bla(CARB-7) gene, making this the first communication of a beta-lactamase gene located on the VCR island of the V. cholerae genome.     

非O1/O139群霍乱弧菌:流行、致病因子和耐药

非O1/O139群霍乱弧菌引起的腹泻在许多发展中国家都有发生,其流行涉及到多个血清群。在有些地方,非O1/O139群霍乱弧菌腹泻的发病率甚至超过了O1/O139群霍乱弧菌腹泻的发病率。非O1/O139群霍乱弧菌的致病因子多种多样,肠毒素、蛋白酶、溶血素和三型分泌系统等被认为是重要的致病因子,但其致病机制非常复杂,至今仍然不完全清楚。随着抗生素使用的增加,出现了许多耐药甚至多重耐药菌株。本研究从非O1/O139群霍乱弧菌腹泻的流行情况、致病因子以及耐药方面加以综述。     

致血流感染非O1群非O139群霍乱弧菌的鉴定及毒力基因检测

目的对襄阳市中心医院分离1株疑似霍乱弧菌进行鉴定及药物敏感性试验,并检测其主要毒力基因。方法利用MicroScan WalkAway 40鉴定仪进行生化鉴定及药物敏感性试验,玻片凝集法确定其血清型别,应用PCR及测序技术分析其16SrRNA基因;PCR检测其6个毒力基因。结果经鉴定,该株疑似霍乱菌株为非O1群非O139群霍乱弧菌,经16SrRNA分析与美国国家生物技术信息中心数据库中霍乱弧菌相似性达100%。药敏试验结果显示该菌对氨苄西林、氯霉素、甲氧苄啶-磺胺甲（口恶）唑、四环素均敏感,毒力基因检测rtxC和toxR阳性,tcpAET、ctxA、hlyA、tcpACL阴性。结论该株疑似霍乱弧菌为非O1群非O139群霍乱弧菌,其致病与rtxC、toxR毒力基因有关。     

广州市一起非O1/O139群霍乱弧菌食物中毒分离株的病原特征分析

目的 了解2014年广州市某工厂发生的一起非O1/O139群霍乱弧菌食物中毒分离株的耐药特性及分子特征。方法 对分离到的6株非O1/O139群分离株进行生化鉴定、血清学鉴定、药物敏感性实验、毒力相关基因检测和脉冲场凝胶电泳（PFGE）分子分型分析。结果 6株分离株经生化鉴定、血清学鉴定为非O1/O139群。药物敏感性分析显示,6株分离株均对氨苄西林、头孢克肟、头孢拉定、阿米卡星、妥布霉素、庆大霉素和多粘菌素B耐药,对诺氟沙星、环丙沙星、复方新诺明、呋喃唑酮、四环素、吡哌酸、红霉素和氯霉素敏感。毒力基因聚合酶链反应检测结果显示,所有菌株均携带毒力表达调控基因（toxR）和溶血素基因（hlyA）,未检出霍乱肠毒素基因（ctxA）、毒力协同调节菌毛基因（tcpA）和肠毒素基因（ST）;5株病例分离株和1株冷柜内壁分离株经限制性内切酶NotⅠ消化后的PFGE图谱为同一型别。结论 此次食物中毒的病原体为非O1/O139群霍乱弧菌,具有共同的遗传特征,菌株出现了多重耐药,提示应加强该类菌株的监测,防止大范围扩散或暴发流行。     

CARB-9, a carbenicillinase encoded in the VCR region of Vibrio cholerae non-O1, non-O139 belongs to a family of cassette-encoded beta-lactamases

The gene bla(CARB-9) was located in the Vibrio cholerae super-integron, but in a different location relative to bla(CARB-7). CARB-9 (pI 5.2) conferred beta-lactam MICs four to eight times lower than those conferred by CARB-7, differing at Ambler's positions V97I, L124F, and T228K. Comparison of the genetic environments of all reported bla(CARB) genes indicated that the CARB enzymes constitute a family of cassette-encoded beta-lactamases.     

Territorial waters of the Baltic Sea as a source of infections caused by Vibrio cholerae non-O1, non-O139: report of 3 hospitalized cases

A fatal infection with temporal relation to 2 other febrile infections caused by Vibrio cholerae non-O1, non-O139 (NCV) occurred in Finland in 2003. All infections were associated with contact with seawater. The patient who died had also eaten home-salted whitefish, tested positive for NCV, preceding his symptoms. All patients had compromising factors, and all strains were distinguishable by pulsed-field gel electrophoresis and negative for the ctx gene. These 3 cases illustrate that, despite being uncommon in Finland, NCVs can cause clinically significant and even fatal infections.     

Vibrio cholerae O1 serotype Ogawa in a neonate

In India, cholera is endemic and affects usually the 3 to 5-year-old age group. There have been occasional reports in the neonatal period with Vibrio cholerae O139 Bengal. We report here a case of Vibrio cholerae O1 diarrhea in a 2-day-old, breastfed male, who had been delivered in the hospital and developed severe dehydration.     

一起引起食物中毒的非O1群霍乱弧菌实验室鉴定

目的 查明引发浙江省宁波市某服饰公司食物中毒事件的病原菌.方法 对采集到可疑食品和肛拭等标本参照GB/T4789-2003标准进行细菌的分离、鉴定及血清学分型;参照霍乱防治手册检测菌株的CT毒力基因.结果 6份患者大便标本与14份轻微腹泻患者或腹部不适者大便标本中检出非O1群霍乱弧菌O29血清型9株,其中腹泻患者标本检出6株,轻微腹泻患者中检出3株,检出率为45.0%.未检出志贺菌、副溶血性弧菌、致病性大肠杆菌、O1群和O139霍乱弧菌、金黄色葡萄球菌等致病菌,剩余食物未检出志贺菌、副溶血性弧菌、致病性大肠杆菌、O1群和O139霍乱弧菌、金黄色葡萄球菌等致病菌.结论 此次食物中毒为非O1群霍乱弧菌O29血清型所致.     

Invasive Vibrio cholerae infection following burn injury.

Vibrio cholerae is a pathogen predominantly appreciated for its potential to produce life-threatening watery diarrhea, usually without invasive disease. However, nonepidemic forms, which are present worldwide, may have a severe invasive presentation, especially among those with liver disease or other immunocompromised states. We present a case of invasive infection (pulmonary, wound, and bacteremia) by nonepidemic V. cholerae, in a soldier that sustained burn injury in Iraq. Multiple factors, to include burn injury and water exposure, likely contributed to this presentation. A brief discussion of the pertinent literature is included.     

Plasmid penicillin resistance in Vibrio cholerae: identification of new beta-lactamase SAR-1.

Two strains of Vibrio cholerae biotype El Tor, isolated in Tanzania, possessed a single IncC resistance plasmid of 113 kilobases. Both plasmids encoded the production of a novel beta-lactamase, SAR-1, which was 33,700 daltons in size and was able to hydrolyze carbenicillin as well as penicillin G. The SAR-1 beta-lactamase was quite distinct from all other plasmid beta-lactamases by virtue of its unusually low isoelectric point and a combination of its size, substrate profile, and inhibition properties. This enzyme is only the second beta-lactamase identified in V. cholerae species and the first to be reported in V. cholerae strains isolated in Southern Africa.     

Transferable Quinolone Resistance in Vibrio cholerae

Ciprofloxacin was introduced for treatment of patients with cholera in Bangladesh because of resistance to other agents, but its utility has been compromised by the decreasing ciprofloxacin susceptibility of Vibrio cholerae over time. We correlated levels of susceptibility and temporal patterns with the occurrence of mutation in gyrA, which encodes a subunit of DNA gyrase, followed by mutation in parC, which encodes a subunit of DNA topoisomerase IV. We found that ciprofloxacin activity was more recently further compromised in strains containing qnrVC3, which encodes a pentapeptide repeat protein of the Qnr subfamily, members of which protect topoisomerases from quinolone action. We show that qnrVC3 confers transferable low-level quinolone resistance and is present within a member of the SXT integrating conjugative element family found commonly on the chromosomes of multidrug-resistant strains of V. cholerae and on the chromosomes of Escherichia coli transconjugants constructed in the laboratory. Thus, progressive increases in quinolone resistance in V. cholerae are linked to cumulative mutations in quinolone targets and most recently to a qnr gene on a mobile multidrug resistance element, resulting in further challenges for the antimicrobial therapy of cholera.Cholera remains a major public health problem in many areas of the developing world. In addition to maintenance oral rehydration therapy, adjunctive antimicrobial therapy reduces the extent and duration of diarrhea, resulting in reduced fluid requirements and hospitalizations, reductions that are particularly important in resource-limited areas. Antimicrobial therapies have included tetracycline, azithromycin, and fluoroquinolones, such as ciprofloxacin, but the activity of fluoroquinolones has decreased in some areas, and this decreased activity has been associated with substantial reductions in the efficacy of ciprofloxacin relative to that of azithromycin (15, 20). To evaluate the evolution of ciprofloxacin resistance in Vibrio cholerae, we studied isolates from Bangladesh available over a 6-year period in which poor clinical responses of cholera patients to ciprofloxacin were recognized. We determined the presence of resistance mutations in genes encoding the subunits of the quinolone target enzymes DNA gyrase (gyrA and gyrB) and DNA topoisomerase IV (parC and parE) and the presence of qnr and other acquired genes that confer additional resistance to quinolones (25). Some qnr gene products have been shown to protect gyrase and topoisomerase IV from quinolone action in enteric bacteria (26, 27). qnr genes are usually located on mobile genetic elements, such as plasmids, that can transfer between strains but have been found on the chromosomes of some Vibrio spp. (5, 18). In V. cholerae, a qnr homolog, qnrVC1, has been described for isolates from Brazil (9) but has not been shown to confer transferable quinolone resistance or to be linked to incremental quinolone resistance and poor response to ciprofloxacin therapy of cholera. We show here that progressively higher levels of resistance in V. cholerae in Bangladesh were driven by accumulating mutations in topoisomerase target enzymes and by the acquisition of a quinolone resistance determinant, qnrVC3, which we identified as part of an SXT integrating conjugative element (4, 10) that also carried genes conferring resistance to tetracycline, trimethoprim-sulfamethoxazole, and streptomycin and accounted for transferable multidrug resistance that included ciprofloxacin in isolates positive for qnrVC3.     

Occurrence of antibiotic resistance gene cassettes aac(6')-Ib,dfrA5, dfrA12, and ereA2 in class I integrons in non-O1, non-O139 Vibrio cholerae strains in India

Molecular mechanisms of multidrug resistance in Vibrio cholerae belonging to non-O1, non-O139 serogroups isolated during 1997 to 1998 in Calcutta, India, were investigated. Out of the 94 strains examined, 22 strains were found to have class I integrons. The gene cassettes identified were dfrA1, dfrA15, dfrA5, and dfrA12 for trimethoprim; aac(6')-Ib for amikacin and tobramycin; aadA1 and aadA2 for streptomycin and spectinomycin; and ereA2 for erythromycin resistance. To our knowledge, this is the first report of the presence of dfrA5, dfrA12, aac(6')-Ib, and ereA2 cassettes in class I integrons of V. cholerae. Forty-three of 94 strains also had plasmids, and out of these, 14 contained both class I integrons and plasmids. Pulsed-field gel electrophoresis followed by Southern hybridization revealed that in the 14 plasmid-bearing strains, class I integrons resided either on chromosomes, on plasmids, or on both. Our results indicated that besides class I integrons and plasmids, a conjugative transposon element, SXT, possibly contributed to the multiple antibiotic resistance.     

Antigenic cross-reactions between Escherichia coli O157, Vibrio cholerae O1 (Inaba) and group N salmonella

Lipopolysaccharide antigen-antibody cross-reactions between Escherichia coli O157 and other members of the Enterobacteriaceae were examined. Using serotyping schemes established in the Laboratory of Enteric Pathogens (LEP), cross-reactions were demonstrated between E. coli O157, Vibrio cholerae O1-Inaba and group N (O = 30) salmonella. SDS-PAGE and immunoblotting showed that the lipopolysaccharide (LPS) of E. coli O157 contained epitopes shared with LPS expressed by group N salmonella. These cross-reactions were also detected using sera from patients with haemolytic uraemic syndrome (HUS) caused by E. coli O157:H7. Rabbit antibodies, prepared to the LPS of V. cholerae O1-Inaba reacted with the LPSs of both E. coli O157 and V. cholerae O1-Inaba, whilst rabbit antisera prepared to E. coli O157 did not react with the LPS of V. cholerae O1-Inaba. Antibodies in sera from patients with HUS, which reacted with the LPS of E. coli O157, did not react with the LPS from V. cholerae O1-Inaba. We concluded from our study that cross-reactions between E. coli O157 and other bacterial species are rare; and that patients infected with bacteria known to share epitopes with E. coli O157 are unlikely to give false positive results when their sera were tested for E. coli O157 serology.     

Toxin, toxin-coregulated pili, and the toxR regulon are essential for Vibrio cholerae pathogenesis in humans

Isogenic mutant strains of V. cholerae O1 lacking elements of a genetic regulon controlled by toxR and implicated in virulence were tested in volunteers. A deletion mutation in ctxA, the gene encoding the A subunit of cholera toxin, markedly attenuated disease symptoms without affecting intestinal colonization. Deletion of toxR, the gene encoding the cholera toxin-positive regulatory protein resulted in a diminution in colonizing capacity. A deletion mutation in tcpA, encoding the major subunit of the toxin coregulated pilus (regulated by toxR), abolished the colonizing capacity of this strain. These results show for the first time the role of a specific pilus structure in colonization of the human intestine by V. cholerae O1 and exemplify the significance of a genetic regulon in pathogenesis.