Showing papers on "El Tor published in 2023"
TL;DR: The initial investigation, ongoing outbreak, and public health response to cholera in Haiti was described in this paper . But, the investigation of the cholerae O1 infection was not concluded until January 3, 2023, and the moving 14-day case fatality ratio was 3.0%.
Abstract: On September 30, 2022, after >3 years with no confirmed cholera cases (1), the Directorate of Epidemiology, Laboratories and Research (DELR) of the Haitian Ministry of Public Health and Population (Ministère de la Santé Publique et de la Population [MSPP]) was notified of two patients with acute, watery diarrhea in the metropolitan area of Port-au-Prince. Within 2 days, Haiti's National Public Health Laboratory confirmed the bacterium Vibrio cholerae O1 in specimens from the two patients with suspected cholera infection, and an outbreak investigation began immediately. As of January 3, 2023, >20,000 suspected cholera cases had been reported throughout the country, and 79% of patients have been hospitalized. The moving 14-day case fatality ratio (CFR) was 3.0%. Cholera, which is transmitted through ingestion of water or food contaminated with fecal matter, can cause acute, severe, watery diarrhea that can rapidly lead to dehydration, shock, and death if not treated promptly (2). Haiti is currently facing ongoing worsening of gang violence, population displacement, social unrest, and insecurity, particularly in the metropolitan area of Port-au-Prince, including Belair, Bas-Delmas, Centre-Ville, Martissant, Cité Soleil, Croix-des Bouquets, and Tabarre, creating an environment that has facilitated the current resurgence of cholera (3). This report describes the initial investigation, ongoing outbreak, and public health response to cholera in Haiti. Cholera outbreak responses require a multipronged, multisectoral approach including surveillance; case management; access to safe water, sanitation, and hygiene (WASH) services; targeted oral cholera vaccine (OCV) campaigns; risk communication; and community engagement. This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy.
6 citations
TL;DR: In this paper , the authors investigated the antimicrobial susceptibility profiles of Vibrio cholerae O1 strains from two consecutive epidemics and examined their associated antimicrobial genetic determinants.
Abstract: Kenya is a country where cholera is endemic; it has experienced three substantial epidemics over the past few decades, but there are limited data on the drug resistance patterns of V. cholerae at the national level. To the best of our knowledge, this is the first study to investigate the antimicrobial susceptibility profiles of V. cholerae O1 strains isolated from two consecutive epidemics and to examine their associated antimicrobial genetic determinants. ABSTRACT Multidrug-resistant Vibrio cholerae O1 strains have long been observed in Africa, and strains exhibiting new resistance phenotypes have emerged during recent epidemics in Kenya. This study aimed to determine the epidemiological aspects, drug resistance patterns, and genetic elements of V. cholerae O1 strains isolated from two cholera epidemics in Kenya between 2007 and 2010 and between 2015 and 2016. A total of 228 V. cholerae O1 strains, including 226 clinical strains isolated from 13 counties in Kenya during the 2007–2010 and 2015–2016 cholera epidemics and two environmental isolates (from shallow well water and spring water isolates) isolated from Pokot and Kwale Counties, respectively, in 2010 were subjected to biotyping, serotyping, and antimicrobial susceptibility testing, including the detection of antibiotic resistance genes and mobile genetic elements. All V. cholerae isolates were identified as El Tor biotypes and susceptible to ceftriaxone, gentamicin, and ciprofloxacin. The majority of isolates were resistant to trimethoprim-sulfamethoxazole (94.6%), streptomycin (92.8%), and nalidixic acid (64.5%), while lower resistance was observed against ampicillin (3.6%), amoxicillin (4.2%), chloramphenicol (3.0%), and doxycycline (1.8%). Concurrently, the integrating conjugative (SXT) element was found in 95.5% of the V. cholerae isolates; conversely, class 1, 2, and 3 integrons were absent. Additionally, 64.5% of the isolates exhibited multidrug resistance patterns. Antibiotic-resistant gene clusters suggest that environmental bacteria may act as cassette reservoirs that favor resistant pathogens. On the other hand, the 2015–2016 epidemic strains were found susceptible to most antibiotics except nalidixic acid. This revealed the replacement of multidrug-resistant strains exhibiting new resistance phenotypes that emerged after Kenya's 2007–2010 epidemic. IMPORTANCE Kenya is a country where cholera is endemic; it has experienced three substantial epidemics over the past few decades, but there are limited data on the drug resistance patterns of V. cholerae at the national level. To the best of our knowledge, this is the first study to investigate the antimicrobial susceptibility profiles of V. cholerae O1 strains isolated from two consecutive epidemics and to examine their associated antimicrobial genetic determinants. Our study results revealed two distinct antibiotic resistance trends in two separate epidemics, particularly trends for multidrug-associated mobile genetic elements and chromosomal mutation-oriented resistant strains from the 2007–2010 epidemic. In contrast, only nalidixic acid-associated chromosomal mutated strains were isolated from the 2015–2016 epidemic. This study also found similar patterns of antibiotic resistance in environmental and clinical strains. Continuous monitoring is needed to control emerging multidrug-resistant isolates in the future.
1 citations
TL;DR: In this article , the authors analyzed Vibrio cholerae (n = 172) associated with endemic cholera in Dhaka during the years 2015-2021 were analyzed for major phenotypic and genetic characteristics, including drug resistance patterns.
Abstract: Despite the advancement in our understanding of cholera and its etiological agent, Vibrio cholerae, the prevention and treatment of the disease are often hindered due to rapid changes in drug response pattern, serotype, and the major genomic islands namely, the CTX-prophage, and related genetic characteristics. In the present study, V. cholerae (n = 172) associated with endemic cholera in Dhaka during the years 2015-2021 were analyzed for major phenotypic and genetic characteristics, including drug resistance patterns.Results revealed that the V. cholerae strains belonged to serogroup O1 biotype El Tor carrying El Tor -specific genes rtxC, tcpA El Tor, and hlyA El Tor, but possessed classical-biotype cholera toxin. Serotypes of V. cholerae strains differed temporally in predominance with Inaba during 2015-2017, and again in 2020-2021, while Ogawa was the predominant serotype in 2018-2019. Also, ctxB1 was predominant in V. cholerae associated with cholera during 2015-2017, while ctxB7 was predominant in 2018, and in the subsequent years, as observed until 2021. V. cholerae strains differed in their antibiotic resistance pattern with a majority (97%) being multi-drug resistant (MDR) and belonging to six sub-groups. Notably, one of these MDR strains was resistant to eleven of the eighteen antibiotics tested, with resistance to fourth-generation cephalosporin (cefepime), and aztreonam. This extreme drug resistant (XDR) strain carried resistance-related genes namely, extended-spectrum β-lactamases (ESBL), blaOXA-1 and blaPER-3.The observed temporal switching of serotypes, as well as the ctxB genotype, and the emergence of MDR/XDR V. cholerae and their association with endemic cholera in Dhaka underscore the need for routine monitoring of the pathogen for proper patient management.
1 citations
TL;DR: In this paper , a comprehensive analysis of Vibrio cholerae O1 and non-O1/non-O139 serogroups isolated from environmental water sources during cholera outbreaks, epidemics and surveillance studies between years 2007 to 2019 from different districts of Odisha, India.
Abstract: Abstract Background The present study reports on the comprehensive analysis of Vibrio cholerae O1 and non-O1/non-O139 serogroups isolated from environmental water sources during cholera outbreaks, epidemics and surveillance studies between years 2007 to 2019 from different districts of Odisha, India. Methods A total of 85 stocked cultures of V. cholerae O1 and non-O1/non-O139 strains were analyzed for different ctx B genotypes, toxic genes, antibiogram profiles through PCR assays and pulsotyped by pulsed-field gel electrophoresis (PFGE). Results From all V. cholerae strains tested, 51 isolates were O1 Ogawa and the rest 34 strains were non-O1/non-O139. All the V. cholerae O1 strains were altered El Tor variants carrying ctx B1, ctx B3 and ctx B7 genotypes. However, only ctx B1 genotypes were present in V. cholerae non-O1/non-O139. Though non-O1/non-O139 strains were negative by O1 antisera, 20% strains were positive for rfbO1 gene by PCR assay. All the V. cholerae isolates possessed a variety of virulence genes including ace, ctxAB, toxR, zot, hlyA which were in higher percentage in the case of V. cholerae O1. The Vibrio cholerae O1 and non-O1-/non-O139 strains showed multiple antibiotic resistances in 2007 and 2012. The PCR detection of four resistance associated genes ( strB, dfrA1, sulll, SXT ) confirmed higher prevalence in V. cholerae non-O1/non-O139 strains. The PFGE analysis revealed 3 pulsotypes having 93% similarity among V. cholerae O1 strains. Conclusion This study indicates the changing epidemiology, antibiogram patterns and continuous genetic variation in environmental V. cholerae strains of Odisha over the years. So continuous surveillance is necessary to understand the changing patterns of V. cholerae different serogroups isolated from stool and water samples from Odisha.
TL;DR: This paper investigated 6 cases in South Africa and found that isolates linked to the outbreak were Vibrio cholerae O1 serotype Ogawa from the seventh pandemic El Tor sublineage AFR15, indicating a new introduction of cholera into Africa from south Asia.
Abstract: Since February 2022, Malawi has experienced a cholera outbreak of >54,000 cases. We investigated 6 cases in South Africa and found that isolates linked to the outbreak were Vibrio cholerae O1 serotype Ogawa from seventh pandemic El Tor sublineage AFR15, indicating a new introduction of cholera into Africa from south Asia.
TL;DR: In this article , the epidemic risk of circulating Vibrio cholerae strains by determining if isolates linked to the ongoing global cholera pandemic ("7PET" lineage) were responsible for outbreaks in Cox's Bazar was inferred.
Abstract: Ongoing diarrheal disease surveillance throughout Bangladesh over the last decade has revealed seasonal localised cholera outbreaks in Cox's Bazar, where both Bangladeshi Nationals and Forcibly Displaced Myanmar Nationals (FDMNs) reside in densely populated settlements. FDMNs were recently targeted for the largest cholera vaccination campaign in decades. We aimed to infer the epidemic risk of circulating Vibrio cholerae strains by determining if isolates linked to the ongoing global cholera pandemic ("7PET" lineage) were responsible for outbreaks in Cox's Bazar. We found two sublineages of 7PET in this setting during the study period; one with global distribution, and a second lineage restricted to Asia and the Middle East. These subclades were associated with different disease patterns that could be partially explained by genomic differences. Here we show that as the pandemic V. cholerae lineage circulates in this vulnerable population, without a vaccine intervention, the risk of an epidemic was very high.
TL;DR: In this paper , the authors conducted a longitudinal study nested under a clinical trial in which samples from a cohort of 223 adults who were vaccinated with two doses of Shanchol™ and followed up over 4 years were used.
Abstract: Histo-blood group antigens (HBGAs) which include the ABO and Lewis antigen systems have been known for determining predisposition to infections. For instance, blood group O individuals have a higher risk of severe illness due to V. cholerae compared to those with non-blood group O antigens. We set out to determine the influence that these HBGAs have on oral cholera vaccine immunogenicity and seroconversion in individuals residing within a cholera endemic area in Zambia.We conducted a longitudinal study nested under a clinical trial in which samples from a cohort of 223 adults who were vaccinated with two doses of Shanchol™ and followed up over 4 years were used. We measured serum vibriocidal geometric mean titers (GMTs) at Baseline, Day 28, Months 6, 12, 24, 30, 36 and 48 in response to the vaccine. Saliva obtained at 1 year post vaccination was tested for HBGA phenotypes and secretor status using an enzyme-linked immunosorbent assay (ELISA).Of the 133/223 participants included in the final analysis, the majority were above 34 years old (58%) and of these, 90% were males. Seroconversion rates to V. cholerae O1 Inaba with non-O (23%) and O (30%) blood types were comparable. The same pattern was observed against O1 Ogawa serotype between non-O (25%) and O (35%). This trend continued over the four-year follow-up period. Similarly, no significant differences were observed in seroconversion rates between the non-secretors (26%) and secretors (36%) against V. cholerae O1 Inaba. The same was observed for O1 Ogawa in non-secretors (22%) and the secretors (36%).Our results do not support the idea that ABO blood grouping influence vaccine uptake and responses against cholera.
TL;DR: In this article , the authors proposed the value of studies that could support the potential of V. cholerae non-toxigenic strains to repress virulence gene expression in cholera-infected humans.
Abstract: Vibrio cholerae, is the causative agent of cholera, that infects millions, annually. Chironomids are aquatic insects that host V. cholerae. Toxigenic strains produce cholera toxin (CT) which is the main virulence factor that causes cholera symptoms. In contrast to other bacterial pathogens, V. cholerae produces CT when at low cell densities while hemagglutinin/protease (HAP) is a high cell density-controlled gene. When V. cholerae behavior was examined on chironomids, we showed that high cell densities of non-toxigenic strains, increased HAP production in a toxigenic strain, conditions which could also potentially reduce CT production. Here we propose the value of studies that could support the potential of V. cholerae non-toxigenic strains to repress virulence gene expression in cholera-infected humans. High cell densities of a non-toxigenic strain present in an infected individual, may down-regulate CT expression, reducing cholera symptoms. To further test the hypothesis supported by a chironomid model, additional experiments in animal models are first needed.
TL;DR: Cholera is an infection caused by toxigenic strains of gram-negative bacterium Vibrio cholerae (O1 or O139) and can be deadly if not treated timely as discussed by the authors .
Abstract: Cholera is an infection caused by toxigenic strains of gram-negative bacterium Vibrio cholerae (O1 or O139), and can be deadly if not treated timely. It is an acute, secretory diarrheal disease that spreads through contaminated food and water. It spreads rapidly and is affecting millions of people each year, resulting in tens of thousands of deaths as a severe diarrheal disease. Of note, cholera has resulted in 7 pandemics during the past 2 centuries1. Cholera is endemic in Iraq and at least in 47 other countries around the world, primarily in Africa and South and South-East Asia as a disease associated mainly with poverty and poor hygienic and sanitation conditions. However, this number is dynamic and the list of affected countries changes frequently2–4. Cholera outbreaks have been rare in developed countries, and its cases typically may get imported from endemic countries by returning travelers. Exposure to cholera is a possible risk for subjects traveling to endemic countries and the infection can be imported from areas where it is endemic or epidemic to cholera-free countries5. In 2017, 12 cases of imported cholera were reported in North America6. Cholera was also reported to be imported from Iraq to Kuwait in 20157. As the World Health Organization (WHO) estimated that officially reported cases represent only 5%–10% of the true number of cases8, the cases of imported cholera might be much higher than that. Cholera is endemic in Iraq and Syria, with periodic outbreaks recorded since 19663,9. Recently, cholera outbreaks have been reported in both Iraq and Syria. As of September 1, 2022, around 1000 confirmed cases of cholera, with 4 associated deaths have been reported from Iraq. The most affected governorates are Kirkuk in the north (480 cases and 3 deaths), Baghdad-Rasafa in the middle region of Iraq (224 cases and 1 death), and Thi-Qar in the south (55 cases). In Syria, the cholera outbreak was declared on September 10, 2022, after 15 confirmed laboratory cases including 1 patient death were reported. The source of infection is believed to be the unsafe water from the Euphrates River and using contaminated water to irrigate crops. In addition, dropping in Euphrates levels with drought-like conditions and underdeveloped national water infrastructure will fuel the situation. In previous outbreaks, the Governments of both countries mobilized a multisectoral response to the outbreak. However, during the current outbreak, it is felt that both governments are reluctant to confirm all cases. While thousands of patients with symptoms and signs of cholera visited hospitals, a small fraction of this number has been confirmed with the V. cholerae infection with 48 deaths among confirmed cases in Iraq and 1 death in Syria10,11. The number of cases and case fatality rate is escalating in both countries12. This might be due to the political instability in both countries and the collective fatigability after the COVID-19 pandemic. The situation may worsen and both countries are prone to increased incidences of cholera cases. In addition, the cholera outbreaks in both countries and particularly in Iraq may have an international impact because of prolong upcoming religious rituals of Al-Arbaeen and related religious events where millions of people from around the world gather in one small city. During those days, people share food and slaughter animals as a part of the holy ritual of Al-Arbaeen. Therefore, it is advised that all countries, whom people travel to these 2 countries (Iraq and Syria), should take needful precautions to prevent the spread of the disease. In countries where cholera is not endemic, medical personnel may not be expecting to see it. Therefore, health care providers need to consider the diagnosis of cholera in any returning travelers with acute watery diarrhea. Visitors and pilgrims must be informed of the risk of cholera, take appropriate preventive measures to avoid infection, and appropriate counselling and self-treatment options (oral rehydration and antibiotics for moderate to severe diarrhea) to mitigate morbidity. If it is possible, vaccine is recommended to all adults travelling to Iraq and other endemic countries1,11. Advances in diagnosis, surveillance and monitoring, molecular epidemiology, immunology, biotechnology, gene sequencing, developing effective vaccines and drugs would certainly support the global roadmap for controlling cholera while limiting transmission in cholera hotspots regions through vaccination, taking due care of emerging drug resistance along with facilitating safer and improved water supplies, checking sewage contamination of drinking water, enhancing sanitation, and hygiene, with the mission to decrease cholera deaths by up to 90% in coming years1,13. Ethical approval This work was written according to the ethical committee of the College of Medicine, University of Zakho criteria. Sources of funding None. Author contribution All authors contributed in this work equally and agreed on the final draft of manuscript. Conflict of interest disclosures The authors declare that they have no financial conflict of interest with regard to the content of this report Research registration unique identifying number (UIN) None. Guarantor All authors.
TL;DR: In this paper , rectal swabs from diarrhea patients were analyzed for the identification, antibiogram profiles and detection of ctxB genotypes by double mismatch amplification mutation (DMAMA) polymerase chain reaction (PCR) assays and sequenced.
Abstract: INTRODUCTION
Cholera is a significant threat causing outbreaks/epidemics with high morbidity and mortality in coastal and tribal districts of Odisha. A sequential cholera outbreak reported from four places in Mayurbhanj district of Odisha during June to July 2009 was investigated.
METHODOLOGY
Rectal swabs from diarrhea patients were analyzed for the identification, antibiogram profiles and detection of ctxB genotypes by double mismatch amplification mutation (DMAMA) polymerase chain reaction (PCR) assays and sequenced. The different virulent and drug resistant genes were detected by multiplex PCR assays. The clonality analysis on selected strains was done by pulse field gel electrophoresis (PFGE).
RESULTS
Bacteriological analysis of rectal swabs revealed the presence of V. cholerae O1 Ogawa biotype El Tor which were resistant to co-trimoxazole, chloramphenicol, streptomycin, ampicillin, nalidixic acid, erythromycin, furazolidone and polymyxin B. DMAMA-PCR assay revealed that the cholera outbreak in Mayurbhanj district was due to both ctxB1 and ctxB7 alleles of V. cholerae O1 El Tor strains. All the V. cholerae O1 strains were positive for all virulence genes. The multiplex PCR assay on V. cholerae O1 strains revealed the presence of antibiotic resistance genes like dfrA1 (100%), intSXT (100%), sulII (62.5%) and StrB (62.5%). PFGE results on V. cholerae O1 strains exhibited two different pulsotypes with 92% similarity.
CONCLUSIONS
This outbreak was a transition phase where both ctxB genotypes were prevalent after which the ctxB7 genotype gradually became dominant in Odisha. Therefore, close monitoring and continuous surveillance on diarrheal disorders is essential to prevent the future diarrheal outbreaks in this region.
TL;DR: Wang et al. as mentioned in this paper integrated analysis of 207 genomes of Hangzhou isolates from these two waves (119 and 88) and 1573 publicly available genomes, and showed that L3b and L9 lineages together caused the second wave as had happened in the first wave, but the dominant lineage shifted from L 3b (first wave: 69%) to L 9 (second wave: 50%).
TL;DR: In this paper , a recombinant plasmid was constructed for Vibrio cholerae that can express intracellular CTB under the control of the toxT-139F allele.
Abstract: The introduction of the toxT-139F allele triggers the expression of TCP (toxin co-regulated pilus) and CT (cholera toxin) under simple laboratory culture conditions in most Vibrio cholerae strains. Such V. cholerae strains, especially strains that have been used in OCVs (oral cholera vaccines), can induce antibody responses against TCP in animal models. However, CT produced in these V. cholerae strains is secreted into the culture medium. In this study, V. cholerae strains that can express intracellular CTB under the control of the toxT-139F allele have been constructed for potential application in OCVs. First, we constructed a recombinant plasmid directly linking the ctxAB promoter to ctxB without ctxA and confirmed CTB expression from the plasmid in V. cholerae containing the toxT-139F allele. We constructed another recombinant plasmid to express NtrCTB, from which 14 internal amino acids—from the 7th to the 20th amino acid—of the leader peptide of CTB have been omitted, and we found that NtrCTB remained in the cells. Based on those results, we constructed V. cholerae strains in which chromosomal ctxAB is replaced by ntrctxB or ntrctxB-dimer. Both NtrCTB and NtrCTB-dimer remained in the bacterial cells, and 60% of the NtrCTB-dimer in the bacterial cells was maintained in a soluble form. To develop improved OCVs, these strains could be tested to see whether they induce immune responses against CTB in animal models.
TL;DR: In this article , the type VI secretion system (T6SS) has gained considerable attention given its ability to mediate interbacterial killing, and the authors performed a comparative in vitro study on T6SS activity using diverse strains or regulatory mutants.
Abstract: Vibrio cholerae is a pathogen that causes disease in millions of people every year by colonizing the small intestine and then secreting the potent cholera toxin. How the pathogen overcomes the colonization barrier created by the host’s natural microbiota is, however, still not well understood. In this context, the type VI secretion system (T6SS) has gained considerable attention given its ability to mediate interbacterial killing. Interestingly, and in contrast to non-pandemic or environmental V. cholerae isolates, strains that are causing the ongoing cholera pandemic (7PET clade) are considered T6SS-silent under laboratory conditions. Since this idea was recently challenged, we performed a comparative in vitro study on T6SS activity using diverse strains or regulatory mutants. We show that modest T6SS activity is detectable in most of the tested strains under interbacterial competition conditions. The system’s activity was also observed through immunodetection of the T6SS tube protein Hcp in culture supernatants, a phenotype that can be masked by the strains’ haemagglutinin/protease. We further investigated the low T6SS activity within the bacterial populations by imaging 7PET V. cholerae at the single-cell level. The micrographs showed the production of the machinery in only a small fraction of cells within the population. This sporadic T6SS production was higher at 30 °C than at 37 °C and occurred independently of the known regulators TfoX and TfoY but was dependent on the VxrAB two-component system. Overall, our work provides new insight into the heterogeneity of T6SS production in populations of 7PET V. cholerae strains in vitro and provides a possible explanation of the system’s low activity in bulk measurements.
TL;DR: In this article , the authors used population genomics to investigate the attributes and origin of the Malawi 2022-2023 Vibrio cholerae (Vc) outbreak isolates and demonstrated the predominance of ST69 seventh cholera pandemic El Tor (7PET) strains expressing O1 Ogawa (~80%) serotype followed by Inaba and typical non-outbreak-associated non-O1/non-ST69 serotypes (~4%).
Abstract: Malawi is experiencing its deadliest Vibrio cholerae (Vc) outbreak following devastating cyclones, with >58,000 cases and >1,700 deaths reported between March 2022 and May 2023. Here, we use population genomics to investigate the attributes and origin of the Malawi 2022-2023 Vc outbreak isolates. Our results demonstrate the predominance of ST69 seventh cholera pandemic El Tor (7PET) strains expressing O1 Ogawa (~80%) serotype followed by Inaba (~16%) and typical non-outbreak-associated non-O1/non-ST69 serotypes (~4%). Phylogenetic reconstruction of the current and historical Vc isolates from Malawi, together with global Vc isolates, suggested the Malawi outbreak strains originated from Asia. The unique antimicrobial resistance and virulence profiles of the 2022-2023 isolates, notably the acquisition of ICEGEN/ICEVchHai1/ICEVchind5 SXT/R391-like integrative conjugative elements and a CTX{varphi} prophage, which caused ctxB3 to ctxB7 genotype shift, support the importation hypothesis. These data suggest that the recent importation of ctxB7 O1 strains, coupled with climatic changes, may explain the magnitude of the cholera outbreak in Malawi.