Non-serogroup O1/O139 agglutinable Vibrio cholerae: a phylogenetically and genealogically neglected yet emerging potential pathogen of clinical relevance

Vibrio cholerae Bacteremia: An Enigma in Cholera-Endemic African Countries

Cholera is highly endemic in many sub-Saharan African countries. The bacterium Vibrio cholerae is responsible for this severe dehydrating diarrheal disease that accounts for over 100,000 deaths each year globally. In recent years, the pathogen has been found to invade intestinal layers and translocate into the bloodstream of humans. The non-toxigenic strains of V. cholerae (non-O1/O139), also known as NOVC, which do not cause epidemic or pandemic cases of cholera, are the major culprits of V. cholerae bacteremia. In non-cholera-endemic regions, clinical reports on NOVC infection have been noted over the past few decades, particularly in Europe and America. Although low-middle-income countries are most susceptible to cholera infections because of challenges with access to clean water and inappropriate sanitation issues, just a few cases of V. cholerae bloodstream infections have been reported. The lack of evidence-based research and surveillance of V. cholerae bacteremia in Africa may have significant clinical implications. This commentary summarizes the existing knowledge on the host risk factors, pathogenesis, and diagnostics of NOVC bacteremia.

Vibriosis in South Asia: A systematic review and meta-analysis

OBJECTIVES

South Asia remains home to foodborne diseases caused by the Vibrio species. We aimed to compile and update information on the epidemiology of vibriosis in South Asia.

METHODS

For this systematic review and meta-analysis, we searched PubMed, Web of Science, EMBASE, and Google Scholar for studies related to vibriosis in South Asia published up to May 2023. A random-effects meta-analysis was used to estimate the pooled isolation rate of non-cholera-causing Vibrio species.

RESULTS

In total, 38 studies were included. Seven of these were case reports and 22 were included in the meta-analysis. The reported vibriosis cases were caused by non-O1/non-O139 V. cholerae, V. parahaemolyticus, V. fluvialis, and V. vulnificus. The overall pooled isolation rate was 4.0% (95% confidence interval [CI] 3.0-5.0%) in patients with diarrhea. Heterogeneity was high (I2 = 98.0%). The isolation rate of non-O1/non-O139 V. cholerae, V. parahaemolyticus, and V. fluvialis were 9.0 (95% CI 7.0-10.0%), 1.0 (95% CI 1.0-2.0%), and 2.0 (95% CI: 1.0-3.0%), respectively. Regarding V. parahaemolyticus, O3:K6 was the most frequently isolated serotype. Cases peaked during summer. Several studies reported antibiotic-resistant strains and those harboring extended-spectrum beta-lactamases genes.

CONCLUSIONS

This study demonstrates a high burden of infections caused by non-cholera-causing Vibrio species in South Asia.

Isolation and Characterization of Cholera Toxin Gene-Positive Vibrio cholerae Non-O1/Non-O139 Isolated from Urinary Tract Infection: A Case Report

Background

Urinary tract infection (UTI) caused by V. cholerae is rare and less common. V. cholerae is a Gram-negative bacterium motile using single polar flagellum and, originally, is a waterborne microbe found in aquatic and estuarine environments. Toxigenic V. cholerae is well-known as a causative agent of acute and excessive watery diarrhea after ingesting food and water contaminated with this bacterium.

Case Presentation

A 27-year-old male patient presented to the emergency department on 17th July 2021 with burning micturition, normal vital signs, and no fever, vomiting, or diarrhea. In 2017, the patient complained of short stature and vitamin D deficiency. He was on human growth hormone from January 2018 till October 2019. The diagnosis was V. cholerae Non-O1/non-O139 urinary tract infection (UTI). Considering a urinary tract infection, empirical treatment with Lornoxicam and Ciprofloxacin was initiated, while the result of urine culture was still pending. The patient was discharged on the same day and without any complications.

Conclusion

V. cholerae non-O1/non-O139 is primarily a marine inhabitant and is associated with sporadic cases resulting in cholera-like diarrhea after consumption of contaminated seafood and exposure to seawater. Extraintestinal infection associated with this bacterium should no longer be ignored as this change in the behavior of cholera bacteria mechanism of pathogenicity might be related to some associated virulence genes.

Polymyxin sensitivity/resistance cosmopolitan status, epidemiology and prevalence among O1/O139 and non-O1/non-O139 Vibrio cholerae: A meta-analysis

Resistance/sensitivity to polymyxin-B (PB) antibiotic has been employed as one among other epidemiologically relevant biotyping-scheme for Vibrio cholerae into Classical/El Tor biotypes. However, recent studies have revealed some pitfalls bordering on PB-sensitivity/resistance (PBR/S) necessitating study. Current study assesses the PBR/S cosmopolitan prevalence, epidemiology/distribution among O1/O139 and nonO1/nonO139 V. cholerae strains. Relevant databases (Web of Science, Scopus and PubMed) were searched to retrieve data from environmental and clinical samples employing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Random-effect-model (REM) and common-effect-model (CEM) of meta-analysis was performed to determine prevalence of PBR/S V. cholerae strains, describe the cosmopolitan epidemiological potentials and biotype relevance. Heterogeneity was determined by meta-regression and subgroup analyses. The pooled analyzed isolates from articles (7290), with sensitive and resistance are 2219 (30.44%) and 5028 (69.56%). Among these PB-sensitive strains, more than 1944 (26.67%) were O1 strains, 132 (1.81%) were nonO1 strains while mis-reported Classical biotype were 2080 (28.53) respectively indicating potential spread of variant/dual biotype. A significant PB-resistance was observed in the models (CEM = 0.66, 95% CI [0.65; 0.68], p-value = 0.001; REM = 0.83 [0.74; 0.90], p = 0.001) as both models had a high level of heterogeneity (I2 = 98.0%; d f = 33 2 = 1755.09 , Q p = 2.4932 ). Egger test (z = 5.4017, p < 0.0001) reveal publication bias by funnel plot asymmetry. The subgroup analysis for continents (Asia, Africa) and sources (acute diarrhea) revealed (98% CI (0.73; 0.93); 55% CI (0.20; 0.86)), and 92% CI (0.67; 0.98). The Epidemiological prevalence for El tor/variant/dual biotype showed 88% CI (0.78; 0.94) with O1 strains at 88% CI (0.78; 0.94). Such global prevalence, distribution/spread of phenotypes/genotypes necessitates updating the decades-long biotype classification scheme. An antibiotic stewardship in the post antibiotic era is suggestive/recommended. Also, there is need for holistic monitoring/evaluation of clinical/epidemiological relevance of the disseminating strains in endemic localities.

Duped by dumping syndrome: non-endemic Vibrio cholerae bacteremia in an immunocompetent host with gastric bypass surgery, a case report

Extra-intestinal infection with non-O1/non-O139 strains of Vibrio cholerae (NOVC) is rare, though bacteremia and hepatobiliary manifestations have been reported. Reduced stomach acid, or hypochlorhydria, can increase risk of V. cholerae infection. We describe a 42-year-old woman with hypochlorhydria due to untreated Helicobacter pylori infection, gastric-bypass surgery, and chronic proton pump inhibitors (PPI) exposure, who developed acute diarrhoea following raw oyster consumption. Her symptoms were attributed to rapid gastric emptying (dumping syndrome) after a negative limited stool work-up. She had persistent diarrhoea, weight loss, and after 5 months was admitted with acute cholecystitis and NOVC bacteremia, requiring cholecystectomy. This is the first reported case of NOVC bacteremia and cholecystitis in a patient with gastric bypass. This case highlights the potential for NOVC biliary carriage, the role of hypochlorhydria as a risk factor for Vibrio infection, and the importance of excluding infectious diarrhoea in patients with new onset of symptoms compatible with dumping syndrome and a relevant travel history.

Whole Genome Analysis of a Non-O1, Non-O139 Vibrio cholerae Detected from Human Blood in China

Non-O1, non-O139 Vibrio cholerae (NOVC) can cause cholera-like diarrhea, but it rarely causes extraintestinal infection, so it is easily overlooked. In this report, we present a case of NOVC detected through blood culture in a 58-year-old male patient with cirrhosis, resulting in severe infection. The patient had been diagnosed with cirrhosis seven years prior and was admitted to the hospital due to abdominal distension and gastrointestinal bleeding. Gram-negative bacilli were isolated from blood cultures and identified as V. cholerae using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and average nucleotide identity (ANI). Moreover, the serum agglutination test showed that the strain was non-O1/non-O139. Further whole genome sequencing and analysis of the strain showed that the strain mainly carried virulence genes tox R, RTX, hly A, T3SS/T6SS, but no resistant genes such as sulII, dfrA1, strB were detected. It provides information for the study of the pathogenic mechanism and drug resistance mechanism of V. cholerae. The patient had severe symptoms and a poor prognosis, indicating that although the NOVC strain infected in this patient had few virulence genes, it was not weak in pathogenicity. It may be caused by the effect of some virulence genes, which should be paid attention to.

Occurrence of waterborne pathogens and antibiotic resistance in water supply systems in a small town in Mozambique

BACKGROUND

. Microbiological quality of drinking water supplied in Moamba, a small town in southern Mozambique, was assessed by collecting and analyzing 91 water sample from 5 sampling sites: raw or inlet water, treated water and 3 household taps along the water distribution system. The presence of Escherichia coli as indicator fecal contamination, three bacterial pathogens, Vibrio cholerae, Salmonella and Campylobacter spp., and Cefotaximee resistant E. coli as antibiotic resistance determinant, was assessed.

RESULTS

. The results showed fecal contamination in all types of water samples: E. coli was found in 100% of inlet water samples, in 21% of treated water samples, and in 22% of tap water samples. No Salmonella spp. was detected during the study. The presence of V. cholerae was detected in 42% of all water samples tested: 100% of inlet water samples, in 16% of treated water samples, and in 23% household tap water samples. All V. cholerae confirmed isolates where genotyped by PCR as non-O1/non-O139; however, 9 isolates showed the presence of the genes encoding for cholera toxin. The presence of Campylobacter spp. was detected in 36% of the water samples tested: in 95% of inlet water samples, in 10% of treated water samples and in 23% household tap water samples. Cefotaxime resistant E. coli was detected in 63% of inlet water, 16% of treated water, and in 9% of tap water samples, these isolates were also resistant to multiple other antibiotics: ampicillin, streptomycin, tetracycline chloramphenicol. All 70 V. cholerae non-O1/non-O139 confirmed isolated were resistant to ampicillin, 51% to streptomycin, 13% to gentamycin, and 1 isolate was resistant to tetracycline; 13% showed a multi-drug resistant profile, being resistant to at least three antibiotics.

CONCLUSION

. The presence of fecal contamination and pathogens in the water treatment system and household taps in Moamba indicates a health risk for the population. This burden increases by the presence of bacterial pathogens showing multidrug resistance.