Bacteriemia por Vibrio cholerae no-O1/no-O139 que porta una región homóloga a la isla de patogenicidad VpaI-7 / Bacteremia caused by Vibrio cholerae non-O1/non-O139 carrying a region homologous to pathogenicity island VpaI-7

Resumen Presentamos un caso de bacteriemia por Vibrio cholerae no-O1/ no-O139 en una mujer de 81 años con un cuadro de dolor abdominal, fiebre, vómitos, diarrea, coluria e ictericia, mientras visitaba una zona rural sin acceso a agua potable. La identificación se realizó por la técnica de espectrometría de masa MALDI-TOF, confirmándose una cepa no toxigénica no-O1/no-139. La caracterización molecular del aislado demostró la ausencia del gen de la toxina del cólera (CTX), y pilus TCP; sin embargo, presentó cinco de los seis genes de virulencia presentes en la isla de patogenicidad homóloga denominada VPaI-7 del V. parahaemolyticus (vcs N2+, vcs C2+, vcs V2+,toxR-, vspD+, T vopF+). Además, el aislado presentó los genes de virulencia hylA y rtxA. Este es el primer caso reportado en Chile de una cepa clínica de V. cholerae no-O1, no-O139 aislada de hemocultivos portador de un segmento homólogo de la isla de patogenicidad denominada VPaI-7 de V. parahaemolyticus, el cual codifica para un sistema de secreción tipo III (TTSS), que probablemente contribuye a su virulencia.

We report a case of V. cholerae non-O1 / non-O139 bacteremia in an 81-year-old woman with abdominal pain, fever, vomiting, liquid stools, choluria and jaundice, while visiting a rural area without access to potable water. The identification was made by the MALDI-TOF mass spectrometry technique and subsequently the non-toxigenic non-O1 / non-139 strain was confirmed in the national reference laboratory. The molecular characterization demonstrated the absence of the cholera toxin gene (CTX), and the TCP pilus, however, presented 5 of 6 virulence genes present in an island of homologous pathogenicity named VPaI-7 of V. parahaemolyticus (vcs N2 +, vcs C2 +, vcs V2 +, toxR-, vspD +, T vopF +) and in addition it was positive for hylAy rtxA virulence genes recognized outside the island. This is the first case reported in Chile of a clinical strain of V. cholerae non-O1, non-O139 isolated from blood culture that carries in its genome a homologous segment of the pathogenicity island named VPaI-7 of V. parahaemolyticus, which codifies for a type III secretion system (TTSS) that probably contributes to his virulence.

Bacteremia por Vibrio cholerae NO-O1/NO-O139 en un paciente cirrótico: Primer reporte de caso en el Perú y revisión de la literatura / Vibrio cholerae NO-O1/NO-O139 bacteremia in a cirrhotic patient: First case report in Peru and literatura review

Vibrio cholerae serogrupo NO-O1/NO-O139 (VCNO) es causa infrecuente de gastroenteritis. Sin embargo, se le asocia a infección extra-intestinal severa en huéspedes inmunocomprometidos, y entre ellas, la bacteremia en pacientes con cirrosis hepática es digna de mención. A continuación, presentamos el caso de una mujer de 58 años, con el diagnóstico de cirrosis hepática de fondo, que desarrolló progresivamente choque séptico, disfunción orgánica múltiple y desenlace fatal al cuarto día de su admisión. Los resultados obtenidos post mortem, de los hemocultivos previamente tomados, aislaron bacilos gram negativos compatibles con Vibrio cholerae. Posteriormente, se identificó el serogrupo NO-O1/NO-O139, a través de aglutinación en placa y PCR negativo para el gen ctxA. El antibiograma mostró susceptibilidad conservada a ampicilina, cloranfenicol, tetraciclina y ciprofloxacino, con resistencia al trimetoprim-sulfametoxazol. El presente caso, descrito en el Hospital Nacional Dos de Mayo, es hasta la fecha, el primer reporte de bacteremia VCNO en el Perú.

Non-O1, non-O139 Vibrio cholerae (NOVC) strains are an uncommon cause of gastroenteritis. However, they have been recently associated with severe extraintestinal infections in immunocompromised hosts. Among them, bacteremia in cirrhotic patients is noteworthy. We present the case of a 58-year-old woman with cirrhosis that developed septic shock, multiple organ failure and died four days after admission. Blood cultures yielded Gram-negative rods identified as Vibrio cholerae. Further serogrouping by slide agglutination and a negative PCR for ctxA gen confirmed the strain to be NOVC. Antimicrobial susceptibility testing showed sensitivity to ampicillin, chloramphenicol, tetracycline and ciprofloxacin; and resistance to trimethoprim-sulfamethoxazole. To the best of our knowledge, this is first report in Peru, described in the Hospital Nacional Dos de Mayo, of NOVC bacteremia.

Characterization of Vibrio cholerae isolates from 1976 to 2013 in Shandong Province, China

Abstract Cholera continues to be a serious public health issue in developing countries. We analyzed the epidemiological data of cholera from 1976 to 2013 in Shandong Province, an eastern coastal area of China. A total of 250 Vibrio cholerae isolates were selected for PCR analysis of virulence genes and pulsed-field gel electrophoresis (PFGE). The analysis of the virulence genes showed that the positive rates for tcpA and tcpI were the highest among strains from the southwest region, which had the highest incidence rate of cholera. Low positive rates for tcpA, tcpI and ctxAB among isolates from after 2000 may be an influencing factor contributing to the contemporary decline in cholera incidence rates. Spatiotemporal serotype shifts (Ogawa, Inaba, Ogawa, Inaba and O139) generally correlated with the variations in the PFGE patterns (PIV, PIIIc, PIa, PIIIb, PIIIa, PIb, and PII). O1 strains from different years or regions also had similar PFGE patterns, while O139 strains exclusively formed one cluster and differed from all other O1 strains. These data indicate that V. cholerae isolates in Shandong Province have continually undergone spatiotemporal changes. The serotype switching between Ogawa and Inaba originated from indigenous strains, while the emergence of serogroup O139 appeared to be unrelated to endemic V. cholerae O1 strains.

Evaluación de la vigilancia microbiológica del cólera / Evaluation of cholera microbiological surveillance

Introducción: el cólera constituye una enfermedad infecciosa, por lo que desde hace más de 40 años ha sido objeto de vigilancia en Cuba. La razón de ser de la vigilancia es la obtención de información, su procesamiento, análisis y elaboración de recomendaciones para la acción oportuna. Objetivo: evaluar la vigilancia microbiológica del cólera en el Centro Provincial de Higiene y Epidemiología de La Habana. Método: se realizó un estudio descriptivo transversal de evaluación táctica en el período del I de octubre al I8 de noviembre del año 20I2. El universo lo constituyeron la Vicedirección de Higiene y Epidemiología y la Vicedirección de Microbiología con sus 22 laboratorios. Se seleccionó una muestra no aleatoria, por conveniencia, que quedó integrada por el jefe de departamento de la unidad de análisis y tendencias de salud, el jefe del programa de control de enfermedades de transmisión digestiva, el vicedirector de microbiología y el personal que se encontraba presente en los laboratorios de agua y de enterobacterias. Se aplicó la metodología de la evaluación rápida propuesta por la Dra. Fariñas, visitándose en un período de 2 días, el laboratorio provincial de microbiología. Resultados: se identificaron brechas existente entre lo que estaba orientado para realizar ante todo paciente sospechosos o confirmado de cólera por parte del laboratorio de microbiología y lo que en realidad se estaba realizando. Conclusiones: las acciones de vigilancia microbiológica del cólera en el Centro Provincial de Higiene y Epidemiología fueron evaluadas de medianamente útil. Estructura medianamente suficiente. Proceso aceptable e impacto satisfactorio...

Background: cholera is an infectious disease, so for more than 40 years it has been under surveillance in Cuba. The reason for monitoring cholera in Cuba is to obtain information, processing, analysis, and development of recommendations for appropriate action. Objective: to evaluate cholera microbiological surveillance in Havana Center of Hygiene and Epidemiology. Method: a descriptive cross-sectional study of tactical assessment was conducted from October to 1st November I8th, 20I2. The universe was formed by vice-direction of Hygiene and Epidemiology and vice-direction of Microbiology with its 22 laboratories. A non-random sample of convenience was chosen. it was composed of the head of the department of the unit for analysis and health trends, the program chief for controlling digestive transmission disease, the deputy director of microbiology and the staff who was present in water laboratories and Enterobacteriaceae. A rapid assessment methodology proposed by Dr. Farinas was applied, visiting the provincial microbiology laboratory over a period of 2 days. Results: existing gaps were identified between what was primarily instructed for a suspected or confirmed case of cholera by the microbiology laboratory and what actually was taking place. Conclusions: cholera microbiological surveillance actions were evaluated fairly useful in Havana Center of Hygiene and Epidemiology, as reasonably sufficient structure, good enough process, and satisfactory impact...

Presence of CTX gene cluster in environmental non-O1/O139 Vibrio cholerae and its potential clinical significance.

Purpose: The aim of this study was to understand the epidemiological linkage of clinical and environmental isolates of Vibrio cholerae and to determine their genotypes and virulence genes content. Materials and Methods: A total of 60 V. cholerae strains obtained from clinical specimens (n = 40) and surface waters (n = 20) were subjected to genotyping using PFGE and determination of their virulence-associated gene clusters. Result: PCR analysis showed the presence of chromosomally located hly and RTX genetic elements in 100% and 90% of the environmental isolates, respectively. The phage-mediated genetic elements such as CTX, TLC and VPI were detected in 5% of the environmental isolates suggesting that the environmental isolates cannot acquire certain mobile gene clusters. A total of 4 and 18 pulsotypes were obtained among the clinical and environmental V. cholerae isolates, respectively. Non-pathogenic environmentally isolated V. cholerae constituted a distinct cluster with one single non-O1, non-O139 strain (EP6) carrying the virulence genes similar to the epidemic strains. This may suggest the possible potential of conversion of non-pathogenic to a pathogenic environmental strain. Conclusions: The emergence of a single environmental isolate in our study containing the pathogenicity genes amongst the diverse non-pathogenic environmental isolates needs to be further studied in the context of V. cholerae pathogenicity sero-coversion.

SXT constin among Vibrio cholerae isolates from a tertiary care hospital.

Background & objectives: The SXT element, also known as ‘constin’ (conjugable, self transmissible, integrating element) is an integrating conjugative element (ICE) in Vibrio cholerae discovered in the chromosome of epidemic V. cholerae O139 strain MO10 (SXTMO10) which arose in late 1992 in Chennai, India. SXT related ICEs have become widespread and currently, most if not all Asian V. cholerae clinical isolates contain SXT related ICEs. The present study attempts to determine the presence of SXT Int gene in V. cholerae recovered between 2005 to 2007 in a tertiary care hospital, demonstrate its conjugal nature and also detect co-presence and co-transfer of plasmids in representative isolates. Methods: This prospective study was done on 116 V. cholerae isolates [114- O1 (107 ogawa and 7 inaba) and 2 - Non O1 Non O139 V. cholerae] from watery stools between 2005 to 2007 recovered from equal number of patients. PCR was carried out using SXT Int specific primers that produced a 592 bp internal fragment of SXT element, and rifampicin resistant strain of E.coli K-12 was used as recipient in conjugation experiments to study transfer of SXT, as also co-transfer of resistance to tetracycline, erythromycin, and nalidixic acid. Antibiotic susceptibility was performed against various antibiotics. Results: Of the 116 isolates, 110 (94.8%) were positive for SXT element by PCR. It was demonstrated in 94.7 per cent of the O1, and 100 per cent of non O1 non O139 V. cholerae. All 2005 isolates, 25 per cent of 2006 isolates and 96.6 per cent of 2007 isolates were positive for SXT. Thirty two drug resistance patterns were observed and the 2007 isolates showed resistance to as many as eight antibiotics. The resistance of SXT positive isolates was higher than those of SXT negative and the typical drug resistance pattern corresponding to SXTET and SXTMO10 was shown by only one V. cholerae O1 isolate. Successful conjugal transfer of SXT was seen in 31 (88.6%) of the 35 isolates studied without any co-transfer while, presence of plasmids was observed in two of the 31 donor V. cholerae studied. Interpretation & Conclusions: The demonstration of SXT element and its successful horizontal transfer in V. cholerae isolates studied emphasizes the need for its detection to monitor antibiotic resistance and dissemination in V. cholerae.

Hybrid & El Tor variant biotypes of Vibrio cholerae O1 in Thailand.

Background & objectives: El Tor Vibrio cholerae O1 carrying ctxBC trait, so-called El Tor variant that causes more severe symptoms than the prototype El Tor strain, first detected in Bangladesh was later shown to have emerged in India in 1992. Subsequently, similar V. cholerae strains were isolated in other countries in Asia and Africa. Thus, it was of interest to investigate the characteristics of V. cholerae O1 strains isolated chronologically (from 1986 to 2009) in Thailand. Methods: A total of 330 V. cholerae O1 Thailand strains from hospitalized patients with cholera isolated during 1986 to 2009 were subjected to conventional biotyping i.e., susceptibility to polymyxin B, chicken erythrocyte agglutination (CCA) and Voges-Proskauer (VP) test. The presence of ctxA, ctxB, zot, ace, toxR, tcpAC, tcpAE, hlyAC and hlyAE were examined by PCR. Mismatch amplification mutation assay (MAMA) - and conventional- PCRs were used for differentiating ctxB and rstR alleles. Results: All 330 strains carried the El Tor virulence gene signature. Among these, 266 strains were typical El Tor (resistant to 50 units of polymyxin B and positive for CCA and VP test) while 64 had mixed classical and El Tor phenotypes (hybrid biotype). Combined MAMA-PCR and the conventional biotyping methods revealed that 36 strains of 1986-1992 were either typical El Tor, hybrid, El Tor variant or unclassified biotype. The hybrid strains were present during 1986-2004. El Tor variant strains were found in 1992, the same year when the typical El Tor strains disappeared. All 294 strains of 1993-2009 carried ctxBC ; 237 were El Tor variant and 57 were hybrid. Interpretation & conclusions: In Thailand, hybrid V. cholerae O1 (mixed biotypes), was found since 1986. Circulating strains, however, are predominantly El Tor variant (El Tor biotype with ctxBC).

Genetic components of stringent response in Vibrio cholerae.

Nutritional stress elicits stringent response in bacteria involving modulation of expression of several genes. This is mainly triggered by the intracellular accumulation of two small molecules, namely, guanosine 3’-diphosphate 5’-triphosphate and guanosine 3’,5’-bis(diphosphate), collectively called (p)ppGpp. Like in other Gram-negative bacteria, the cellular level of (p)ppGpp is maintained in Vibrio cholerae, the causative bacterial pathogen of the disease cholera, by the products of two genes relA and spoT. However, apart from relA and spoT, a novel gene relV has recently been identified in V. cholerae, the product of which has been shown to be involved in (p)ppGpp synthesis under glucose or fatty acid starvation in a ΔrelA ΔspoT mutant background. Furthermore, the GTP binding essential protein CgtA and a non-DNA binding transcription factor DksA also seem to play several important roles in modulating stringent response and regulation of other genes in this pathogen. The present review briefly discusses about the role of all these genes mainly in the management of stringent response in V. cholerae.

The complexity of ToxT-dependent transcription in Vibrio cholerae.

Vibrio cholerae is the causative agent of the disease cholera, characterized by profuse watery diarrhoea. Two of the main virulence factors associated with the disease are cholera toxin (CT) and toxin-coregulated pilus (TCP). Expression of CT and TCP is regulated via a complex cascade of factors that respond to environmental signals, but ultimately ToxT is the direct transcriptional activator of the genes encoding CT and TCP. Recent studies have begun to unveil the mechanisms behind ToxT-dependent transcription. We review current knowledge of transcriptional activation by ToxT and the environmental stimuli that allow ToxT to regulate virulence gene expression, resulting in cholera pathogenesis.

Molecular mechanism of acquisition of the cholera toxin genes.

One of the major pathogenic determinants of Vibrio cholerae, the cholera toxin, is encoded in the genome of a filamentous phage, CTX. CTX makes use of the chromosome dimer resolution system of V. cholerae to integrate its single stranded genome into one, the other, or both V. cholerae chromosomes. Here, we review current knowledge about this smart integration process.

The discovery of cholera - like enterotoxins produced by Escherichia coli causing secretory diarrhoea in humans.

Non-vibrio cholera has been recognized as a clinical entity for as long as cholera was known to be caused by Vibrio cholerae. Until 1968, the aetiologic agent of this syndrome was not known. Following a series of studies in patients with non-vibrio cholera it was found that these patients had large concentrations of Escherichia coli in the small bowel and stools which produced cholera toxin-like enterotoxins, and had fluid and electrolyte transport abnormalities in the small bowel similar to patients with documented cholera. Furthermore, these patients developed antibodies to the cholera-like enterotoxin. Later studies showed that these strains, when fed to volunteers produced a cholera-like disease and that two enterotoxins were found to be produced by these organisms: a heat-labile enterotoxin (LT) which is nearly identical to cholera toxin, and a heat-stable enterotoxin (ST), a small molecular weight polypeptide. E. coli that produced one or both of these enterotoxins were designated enterotoxigenic E. coli (ETEC). ETEC are now known not only to cause a severe cholera-like illness, but to be the most common bacterial cause of acute diarrhoea in children in the developing world, and to be the most common cause of travellers’ diarrhoea in persons who visit the developing world.

Lessons from cholera & Vibrio cholerae.

Cholera is an acute form of diarrhoeal disease that plagued human civilization over the centuries. The sudden and explosive onset of the disease in the form of an outbreak or epidemic, coupled with high mortality and morbidity rates, had a tragic impact on the personal as well as social life of people living in the affected areas. The enormity of human sufferings led clinicians and scientists to carry out extensive research on cholera and Vibrio cholerae (the causative bacterium of the disease) leading to major discoveries that opened up novel areas of research or new disciplines in biomedical sciences. An attempt is made here to summarize some of these breakthroughs and outline their significance in broader perspectives. Finally, the possible impact of the global socio-political scenario on the spread of cholera epidemics (pandemicity of cholera) is briefly discussed.

A De in the life of cholera.

The 50-year commemoration of S.N. De’s seminal 1959 publication in Nature provides an opportunity to reflect on scientific discovery, recognition, and public health. De’s paper marked the first major conceptual advance in cholera research since 1884, when Robert Koch definitively identified Der Kommabazillus as the aetiological agent of cholera. Unfortunately, Koch reported that systemic toxinosis and multi-organ failure led to severe dehydrating diarrhoea, thereby mistaking cause for effect. As a consequence, while work on other microbial pathogens advanced into the development of vaccines and therapeutics, cholera research languished as scientists injected animals parenterally in decades of futile effort to develop an animal model of diarrhoea. This fundamental misconception in cholera pathogenesis was swept away when S.N. De used ligated loops of rabbit ileum to demonstrate lumenal fluid accumulation in the presence of Vibrio cholerae culture filtrates. After some delay, De’s observation of a diarrhoeagenic exotoxin became the founding principle of modern cholera research, vaccination, and treatment; and a burst of discovery saw V. cholerae transformed into the enteric pathogen best understood at the molecular level. The scientific basis for orally administering vaccines to induce mucosal immunity was established, and the success of oral rehydration, what has been described as one of the 20th century’s most important medical advances, was explained.Nobel laureate Joshua Lederberg wrote of De’s iconoclastic creativity, experimental skill, and observational mastery, and many other leaders in the field concurred. De was nominated for the Nobel Prize in Physiology or Medicine more than once. But despite the passage of half a century from De’s work, cholera remains a frustrating problem: we are clearly missing something. In reviewing the scientific and programmatic impact of S.N. De on cholera, it is clear that a defining victory against the disease is achievable, but only if basic scientific discoveries are relentlessly driven towards progress in public health.

Influence of relative humidity in Vibrio cholerae infection: A time series model.

Background & objectives : Spread of cholera in West Bengal is known to be related to its ecosystem which favours Vibrio cholerae. Incidence of cholera has not been correlated with temperature, relative humidity and rainfall, which may act as favourable factors. The aim of this study was to investigate the relational impact of climate changes on cholera. Methods : Monthly V. cholerae infection data for of the past 13 years (1996-2008), average relative humidity (RH), temperature and rainfall in Kolkata were considered for the time series analysis of Seasonal Auto-Regressive Integrated Moving Average (SARIMA) model to investigate relational impact of climatic association of V. cholerae infection and General Linear Model (GLM) for point estimation. Results : The SARIMA (1,0,0)(0,1,1) model revealed that monthly average RH was consistently linear related to V. cholerae infection during monsoon season as well as temperature and rainfall were non-stationary, AR(1), SMA(1) and SI(1) (P<0.001) were highly significant with seasonal difference. The GLM has identified that consistent (<10%) range of RH (86.78 ± 4.13, CV=5.0, P <0.001) with moderate to highest (>7 cm) rainfall (10.1 ± 5.1, CV=50.1, P <0.001) and wide (>5-10°C) range of temperature (29.00 ± 1.64, CV=5.6, P <0.001) collectively acted as an ideal climatic condition for V. cholerae infection. Increase of RH to 21 per cent influenced an unusual V. cholerae infection in December 2008 compared to previous years. Interpretation & conclusions : V. cholerae infection was associated higher RH (>80%) with 29°C temperature with intermittent average (10 cm) rainfall. This model also identified periodicity and seasonal patterns of cholera in Kolkata. Heavy rainfall indirectly influenced the V. cholerae infection, whereas no correlation was found with high temperature.

Atypical presentation of vibrio cholera

Cholera is known to be one of the most infectious diseases and is characterized by profuse watery diarrhea, vomiting and muscular cramps leading to dehydration, collapse and high mortality. Cholera is not endemic in Kuwait. We report a case of a Kuwaiti patient with atypical presentation of cholera that was diagnosed accidently by detection of Vibrio cholera in constipated stool. The patient was given treatment and discharged after clinical and laboratory cure. This patient is considered the first Kuwaiti cholera carrier over last ten years [documented by prevention control department in Kuwait]

Occurrence and composition of class 1 and class 2 integrons in clinical and environmental O1 and non-O1/non-O139 Vibrio cholerae strains from the Brazilian Amazon

This study identified and characterised class 1 and 2 integrons in clinical and environmental Vibrio cholerae O1 and non-O1/non-O139 strains isolated from the Brazilian Amazon. The aadA2 and aadA7 gene cassettes were found in class 1 integrons in two genotypes of environmental V. cholerae non-O1/non-O139. Empty integrons were found in strains from the Brazilian cholera epidemic. A class 2 integron was detected in one strain from the V. cholerae Amazonia lineage harbouring sat1 and aadA1 genes. All isolates were resistant to aminoglycosides, indicating aadA functionality. These findings suggest that environmental bacteria act as cassette reservoirs that favour the emergence of resistant pathogens.

Prevalence of cholera in pediatric patients with acute dehydrating diarrhea.

Objective. To estimate the prevalence of culture-confirmed cholera in patients with acute dehydrating diarrhea, at a tertiary care center in north India, during a 6-month period from March to August, 2006. Methods. We studied 145 children, who presented to the pediatric emergency services of a tertiary care teaching hospital in north India with acute dehydrating diarrhea. Each patient had his/her stool sample collected for Vibrio cholerae culture and hanging drop preparation for darting motility. The stool specimen for hanging drop analysis was immediately transported to the emergency laboratory, where a trained technician prepared the slides and examined them for darting motility characteristic of Vibrio cholerae. Results. V. cholerae was isolated in 36 (24.8%) patients. Forty-nine (33.7%) patients had a positive hanging drop examination. Hanging drop examination had a sensitivity and specificity of 85.8% and 81.7%, respectively. Severe dehydration (OR 4.3; P<0.01) and hanging drop positivity (OR 12.42; P<0.001) were associated with higher odds of cholera after adjustment for other risk factors. Conclusion. Cholera is an important cause of acute watery diarrhea in pediatric patients in urban north India and should be ruled out in all children presenting with acute dehydrating diarrhea, particularly those with severe dehydration. Hanging drop test is useful for diagnosis in the emergency setting.