Dissemination of Polymyxin B Sensitivity in El Tor <i>Vibrio cholerae</i> O1 Strains in Odisha, India

ABSTRACTAntimicrobial peptides are critical for innate antibacterial defense. Both Gram-negative and Gram-positive microbes have mechanisms to alter their surfaces and resist killing by antimicrobial peptides. InVibrio cholerae, two natural epidemic biotypes, classical and El Tor, exhibit distinct phenotypes with respect to sensitivity to the peptide antibiotic polymyxin B: classical strains are sensitive and El Tor strains are relatively resistant. We carried out mutant screens of both biotypes, aiming to identify classicalV. choleraemutants resistant to polymyxin B and El TorV. choleraemutants sensitive to polymyxin B. Insertions in a gene annotatedmsbB(encoding a predicted lipid A secondary acyltransferase) answered both screens, implicating its activity in antimicrobial peptide resistance ofV. cholerae. Analysis of a defined mutation in the El Tor biotype demonstrated thatmsbBis required for resistance to all antimicrobial peptides tested. Mutation ofmsbBin a classical strain resulted in reduced resistance to several antimicrobial peptides but in no significant change in resistance to polymyxin B.msbBmutants of both biotypes showed decreased colonization of infant mice, with a more pronounced defect observed for the El Tor mutant. Mass spectrometry analysis showed that lipid A of themsbBmutant for both biotypes was underacylated compared to lipid A of the wild-type isolates, confirming that MsbB is a functional acyltransferase inV. cholerae.

Download Full-text

Vibrio cholerae O1 clinical strains isolated in 1992 in Kolkata with progenitor traits of the 2004 Mozambique variant

Journal of Medical Microbiology ◽

10.1099/jmm.0.003780-0 ◽

2009 ◽

Vol 58 (2) ◽

pp. 239-247 ◽

Cited By ~ 17

Author(s):

Souvik Chatterjee ◽

Tapas Patra ◽

Kausik Ghosh ◽

Amit Raychoudhuri ◽

Gururaja P. Pazhani ◽

...

Keyword(s):

Retrospective Analysis ◽

Vibrio Cholerae ◽

Polymyxin B ◽

Small Chromosome ◽

Phenotypic Traits ◽

Clinical Strains ◽

Vibrio Cholerae O1 ◽

Ctx Prophage ◽

El Tor ◽

Clinical Cases

Retrospective analysis led to the detection of two Vibrio cholerae variant O1 strains (VC51 and VC53), which were isolated in 1992 in Kolkata from clinical cases, with identical traits to 2004 Mozambique variant O1 strains. The Mozambique O1 strains that caused a huge outbreak in 2004 have been shown to have phenotypic traits of both classical and El Tor biotypes, and thereby have been reported as variant. Our study demonstrated that two O1 strains isolated in Kolkata during 1992 were of the El Tor background as evidenced by polymyxin B (50 U ml−1) resistance, positivity in Voges–Proskauer reactions and sensitivity to biotype-specific vibrio phages. With the features of classical CTX prophage, localization in the small chromosome, and an absence of RS1 and pTLC, both Mozambique and Kolkata strains appeared to be identical. Furthermore, two Kolkata strains exhibited an identical ribotype to that of the Mozambique variant, displaying ribotype pattern RI that had been assigned to Kolkata V. cholerae O1 strains isolated on or before 1992. NotI pulsotype analysis indicated that these 1992 Kolkata strains along with the Mozambique variant O1 belonged to very closely related clones. Considering the chronological events, and the typical identity at the phenotypic and the genotypic level between the two O1 strains isolated during 1992 from Kolkata and during 2004 from Mozambique, we propose that some of the 1992 Kolkata O1 strains might have acted as progenitors for Mozambique variant O1 strains.

Download Full-text

Identification of Vibrio cholerae O1 strains of the El Tor biovar sensitive to polymyxin B and their molecular genetic analysis

Journal of microbiology epidemiology immunobiology ◽

10.36233/0372-9311-138 ◽

2021 ◽

Vol 98 (5) ◽

pp. 538-547

Author(s):

S. P. Zadnova ◽

Ya. M. Krasnov ◽

N. A. Plekhanov ◽

A. A. Kritskiy ◽

V. V. Kutyrev

Keyword(s):

Vibrio Cholerae ◽

Environmental Samples ◽

Genetically Modified ◽

Polymyxin B ◽

Molecular Genetic Analysis ◽

Photometric Method ◽

Snp Analysis ◽

Parsimony Method ◽

Cholera Vibrio ◽

El Tor

The aim of the work was the identification and genetic characterization of Vibrio cholerae O1 strains of the El Tor biovar sensitive to polymyxin B among isolates imported to Russia.Materials and methods. We used 56 toxigenic and non-toxigenic strains of V. cholerae isolated from patients and from the environmental samples on the territory of Russia in 1970-2020. Resistance to polymyxin B was determined according to MR4.2.2218-07. The ability of strains to form a biofilm on the abiotic surface was assessed by a photometric method. Nucleotide sequences of genes were determined using UGENE 1.32 and MEGA X software. Phylogenetic analysis and tree construction were performed using "maximum parsimony" method in MEGA X software.Results and discussion. Two genetically modified strains of V. cholerae O1 biovar El Tor, M1509 and 3265/80, which were imported to Russia from India in 2012 and 2014, respectively, were identified. The analysis of 12 genes responsible for the resistance of V. cholerae O1 biovar El Tor strains to polymyxin B demonstrated that these strains contain the allele of the carRS gene, which is typical for all strains of cholera vibrio sensitive to polymyxin B. Study of V. cholerae M1509 and 3265/80 phylogeny based on SNP analysis showed that they fall into the same cluster with isolates containing the carRS allele isolated in India (2015) and Bangladesh (2018). V. cholerae M1509 and 3256/8 strains had the ability to form a biofilm similar to those observed in other genetically modified strains of cholera vibrio included into analysis.Conclusion. Highly virulent strains of the cholera agent with altered diagnostically significant features are imported into Russia, which should be taken into account when identifying V. cholerae O1 biovar El Tor strains isolated from patients and environmental samples during monitoring studies.

Download Full-text

A Point Mutation in carR Is Involved in the Emergence of Polymyxin B-Sensitive Vibrio cholerae O1 El Tor Biotype by Influencing Gene Transcription

Infection and Immunity ◽

10.1128/iai.00080-20 ◽

2020 ◽

Vol 88 (5) ◽

Cited By ~ 1

Author(s):

Prosenjit Samanta ◽

Rahul Shubhra Mandal ◽

Rudra Narayan Saha ◽

Sreeja Shaw ◽

Priyanka Ghosh ◽

...

Keyword(s):

Vibrio Cholerae ◽

Lipid A ◽

Polymyxin B ◽

Sensitive Strain ◽

Two Component System ◽

Content Type ◽

Vibrio Cholerae O1 ◽

Binding Cleft ◽

Culturing Conditions ◽

El Tor

ABSTRACT Antimicrobial peptides play an important role in host defense against Vibrio cholerae. Generally, the V. cholerae O1 classical biotype is polymyxin B (PB) sensitive and El Tor is relatively resistant. Detection of classical biotype traits like the production of classical cholera toxin and PB sensitivity in El Tor strains has been reported in recent years, including in the devastating Yemen cholera outbreak during 2016-2018. To investigate the factor(s) responsible for the shift in the trend of sensitivity to PB, we studied the two-component system encoded by carRS, regulating the lipid A modification of El Tor vibrios, and found that only carR contains a single nucleotide polymorphism (SNP) in recently emerged PB-sensitive strains. We designated the two alleles present in PB-resistant and -sensitive strains carRr and carRs alleles, respectively, and replaced the carRs allele of a sensitive strain with the carRr allele, using an allelic-exchange approach. The sensitive strain then became resistant. The PB-resistant strain N16961 was made susceptible to PB in a similar fashion. Our in silico CarR protein models suggested that the D89N substitution in the more stable CarRs protein brings the two structural domains of CarR closer, constricting the DNA binding cleft. This probably reduces the expression of the carR-regulated almEFG operon, inducing PB susceptibility. Expression of almEFG in PB-sensitive strains was found to be downregulated under natural culturing conditions. In addition, the expression of carR and almEG decreased in all strains with increased concentrations of extracellular Ca2+ but increased with a rise in pH. The downregulation of almEFG in CarRs strains confirmed that the G265A mutation is responsible for the emergence of PB-sensitive El Tor strains.

Download Full-text

Characterization of a clinicalVibrio choleraeO139 isolate from Mexico

Canadian Journal of Microbiology ◽

10.1139/w03-004 ◽

2003 ◽

Vol 49 (1) ◽

pp. 65-70 ◽

Cited By ~ 3

Author(s):

Salina Parveen ◽

Samuel R Farrah ◽

Celia Gonzalez-Bonilla ◽

Altagracia V Zamudio ◽

Mark L Tamplin

Keyword(s):

Cholera Toxin ◽

Vibrio Cholerae ◽

Gel Electrophoresis ◽

Polymyxin B ◽

Pulsed Field Gel Electrophoresis ◽

Phenotypic Characteristics ◽

Vibrio Cholerae O139 ◽

A Subunit ◽

El Tor

Pathogenic strains of Vibrio cholerae O139 possess the cholera toxin A subunit (ctxA) gene as well as the gene for toxin co-regulated pili (tcpA). We report the isolation of a ctxA-negative, tcpA-negative V. cholerae O139 strain (INDRE1) from a patient in Mexico diagnosed with gastrointestinal illness. Certain phenotypic characteristics of this strain were identical to those of V. cholerae O1 biotype El Tor. Unlike ctxA-positive V. cholerae O139 strains, this strain was sensitive to a wide panel of antibiotics, including ampicillin, chloramphenicol, ciprofloxacin, gentamicin, furazolidone, nalidixic acid, nitrofurantoin, tetracycline, trimethoprim-sulfamethoxazole, and streptomycin, but was resistant to polymyxin B. Ribotype and pulsed-field gel electrophoresis profiles of INDRE1 differed from those of ctxA-positive V. cholerae O139 and other V. cholerae strains. Phenotypic characteristics of the Mexico strain were similar to those reported for V. cholerae O139 isolates from Argentina and Sri Lanka.Key words: Vibrio cholerae O139, cholera toxin, ctxA, tcpA.

Download Full-text

Atypical and dual biotypes variant of virulent SA-NAG-Vibrio cholerae: an evidence of emerging/evolving patho-significant strain in municipal domestic water sources

Annals of Microbiology ◽

10.1186/s13213-021-01661-5 ◽

2022 ◽

Vol 72 (1) ◽

Author(s):

Bright E. Igere ◽

Anthony I. Okoh ◽

Uchechukwu U. Nwodo

Keyword(s):

Vibrio Cholerae ◽

Ground Surface ◽

Polymyxin B ◽

Protease Production ◽

Eastern Cape Province ◽

Eastern Cape ◽

Domestic Water ◽

Public Health Systems ◽

Microbiological Methods ◽

El Tor

Abstract Introduction and purpose The recent cholera spread, new cases, and fatality continue to arouse concern in public health systems; however, interventions on control is at its peak yet statistics show continuous report. This study characterized atypical and patho-significant environmental Vibrio cholerae retrieved from ground/surface/domestic water in rural-urban-sub-urban locations of Amathole District municipality and Chris Hani District municipality, Eastern Cape Province, South Africa. Methods Domestic/surface water was sampled and 759 presumptive V. cholerae isolates were retrieved using standard microbiological methods. Virulence phenotypic test: toxin co-regulated pili (tcp), choleragen red, protease production, lecithinase production, and lipase test were conducted. Serotyping using polyvalent antisera (Bengal and Ogawa/Inaba/Hikojima) and molecular typing: 16SrRNA, OmpW, serogroup (Vc-O1/O139), biotype (tcpAClas/El Tor, HlyAClas/El Tor, rstRClas/El Tor, RS1, rtxA, rtxC), and virulence (ctxA, ctxB, zot, ace, cep, prt, toxR, hlyA) genes were targeted. Result Result of 16SrRNA typing confirmed 508 (66.9%) while OmpW detected/confirmed 61 (12.01%) V. cholerae strains. Phenotypic-biotyping scheme showed positive test to polymyxin B (68.9%), Voges proskauer (6.6%), and Bengal serology (11.5%). Whereas Vc-O1/O139 was negative, yet two of the isolates harbored the cholera toxin with a gene-type ctxB and hlyAClas: 2/61, revealing atypical/unusual/dual biotype phenotypic/genotypic features. Other potential atypical genotypes detected include rstR: 7/61, Cep: 15/61, ace: 20/61, hlyAElTor: 53/61, rtxA: 30/61, rtxC: 11/61, and prtV: 15/61 respectively. Conclusion Although additional patho-significant/virulent genotypes associated with epidemic/sporadic cholera cases were detected, an advanced, bioinformatics, and post-molecular evaluation is necessary. Such stride possesses potential to adequately minimize future cholera cases associated with dynamic/atypical environmental V. cholerae strains.

Download Full-text