Vibrio cholerae pathogenicity island 2 encodes two distinct types of restriction systems.

In response to predation by bacteriophages and invasion by other mobile genetic elements such as plasmids, bacteria have evolved specialized defense systems that are often clustered together on genomic islands. The O1 El Tor strains of Vibrio cholerae responsible for the ongoing seventh cholera pandemic (7PET) contain a characteristic set of genomic islands involved in host colonization and disease, many of which contain defense systems. Notably, Vibrio pathogenicity island 2 contains several characterized defense systems as well as a putative type I restriction-modification (T1RM) system, which, interestingly, is interrupted by two genes of unknown function. Here, we demonstrate that the T1RM system is active, methylates the host genomes of a representative set of 7PET strains, and identify a specific recognition sequence that targets non-methylated plasmids for restriction. We go on to show that the two genes embedded within the T1RM system encode a novel two-protein modification-dependent restriction system related to the GmrSD family of type IV restriction enzymes. Indeed, we show that this system has potent anti-phage activity against diverse members of the Tevenvirinae, a subfamily of bacteriophages with hypermodified genomes. Taken together, these results expand our understanding of how this highly conserved genomic island contributes to the defense of pandemic V. cholerae against foreign DNA. IMPORTANCE: Defense systems are immunity systems that allow bacteria to counter the threat posed by bacteriophages and other mobile genetic elements. Although these systems are numerous and highly diverse, the most common types are restriction enzymes that can specifically recognize and degrade non-self DNA. Here, we show that the Vibrio pathogenicity island 2, present in the pathogen Vibrio cholerae, encodes two types of restriction systems that use distinct mechanisms to sense non-self DNA. The first system is a classical Type I restriction-modification system, and the second is a novel modification-dependent type IV restriction system that recognizes hypermodified cytosines. Interestingly, these systems are embedded within each other, suggesting that they are complementary to each other by targeting both modified and non-modified phages.

DdmABC-dependent death triggered by viral palindromic DNA sequences.

Defense systems that recognize viruses provide important insights into both prokaryotic and eukaryotic innate immunity mechanisms. Such systems that restrict foreign DNA or trigger cell death have recently been recognized, but the molecular signals that activate many of these remain largely unknown. Here, we characterize one such system in pandemic Vibrio cholerae responsible for triggering cell density-dependent death (CDD) of cells in response to the presence of certain genetic elements. We show that the key component is the Lamassu DdmABC anti-phage/plasmid defense system. We demonstrate that signals that trigger CDD were palindromic DNA sequences in phages and plasmids that are predicted to form stem-loop hairpins from single-stranded DNA. Our results suggest that agents that damage DNA also trigger DdmABC activation and inhibit cell growth. Thus, any infectious process that results in damaged DNA, particularly during DNA replication, can in theory trigger DNA restriction and death through the DdmABC abortive infection system.

Vibrio cholerae O1 and Escherichia coli O157:H7 from drinking water and wastewater in Addis Ababa, Ethiopia.

BACKGROUND: In Addis Ababa, Ethiopia, open ditches along innner roads in residential areas serve to convey domestic wastewater and rainwater away from residences. Contamination of drinking water by wastewater through faulty distribution lines could expose households to waterborne illnesses. This prompted the study to assess the microbiological safety of wastewater and drinking water in Addis Ababa, identify the pathogens therein, and determine their antibiotic resistance patterns. RESULTS VIBRIO CHOLERAE: O1, mainly Hikojima serotype, was isolated from 23 wastewater and 16 drinking water samples. Similarly, 19 wastewater and 10 drinking water samples yielded Escherichia coli O157:H7. V. cholerae O1 were 100% resistant to the penicillins (Amoxacillin and Ampicillin), and 51-82% were resistant to the cephalosporins. About 44% of the V. cholerae O1 isolates in this study were Extended Spectrum Beta-Lactamase (ESBL) producers. Moreover, 26% were resistant to Meropenem. Peperacillin/Tazobactam was the only effective ß-lactam antibiotic against V. cholerae O1. V. cholerae O1 isolates showed 37 different patterns of multiple resistance ranging from a minimum of three to a maximum of ten antimicrobials. Of the E. coli O157:H7 isolates, 71% were ESBL producers. About 96% were resistant to Ampicillin. Amikacin and Gentamicin were very effective against E. coli O157:H7 isolates. The isolates from wastewater and drinking water showed multiple antibiotic resistance against three to eight antibiotic drugs. CONCLUSIONS: Open ditches for wastewater conveyance along innner roads in residence areas and underground faulty municipal water distribution lines could be possible sources for V. cholerae O1 and E. coli O157:H7 infections to surrounding households and for dissemination of multiple drug resistance in humans and, potentially, the environment.

Detection of pathogenic Vibrio spp. in foods: polymerase chain reaction-based screening strategy to rapidly detect pathogenic Vibrio parahaemolyticus, Vibrio cholerae, and Vibrio vulnificus in bivalve mollusks and preliminary results.

The majority of human diseases attributed to seafood are caused by Vibrio spp., and the most commonly reported species are Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae. The conventional methods for the detection of Vibrio species involve the use of selective media, which are inexpensive and simple but time-consuming. The present work aimed to develop a rapid method based on the use of multiplex real-time polymerase chain reaction (PCR) to detect V. parahaemolyticus, V. vulnificus, and V. cholerae in bivalve mollusks. 30 aliquots of bivalve mollusks (Mytilus galloprovincialis) were experimentally inoculated with two levels of V. parahaemolyticus, V. vulnificus, and V. cholerae. ISO 21872-1:2017 was used in parallel for qualitative analysis. The limit of detection of 50% was 7.67 CFU/g for V. cholerae, 0.024 CFU/g for V. vulnificus, and 1.36 CFU/g for V. parahaemolyticus. For V. vulnificus and V. cholerae, the real-time PCR protocol was demonstrated to amplify the pathogens in samples seeded with the lowest and highest levels. The molecular method evaluated showed a concordance rate of 100% with the reference microbiological method. V. parahaemolyticus was never detected in samples contaminated with the lowest level, and it was detected in 14 samples (93.33%) seeded with the highest concentration. In conclusion, the developed multiplex real-time PCR proved to be reliable for V. vulnificus and V. cholerae. Results for V. parahaemolyticus are promising, but further analysis is needed. The proposed method could represent a quick monitoring tool and, if used, would allow the implementation of food safety.

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.

CRISPR RNA-Guided Transposases Facilitate Dispensable Gene Study in Phage.

Phages provide a potential therapy for multi-drug-resistant (MDR) bacteria. However, a significant portion of viral genes often remains unknown, posing potential dangers. The identification of non-essential genes helps dissect and simplify phage genomes, but current methods have various limitations. In this study, we present an in vivo two-plasmid transposon insertion system to assess the importance of phage genes, which is based on the V. cholerae transposon Tn6677, encoding a nuclease-deficient type I-F CRISPR-Cas system. We first validated the system in Pseudomonas aeruginosa PAO1 and its phage S1. We then used the selection marker AcrVA1 to protect transposon-inserted phages from CRISPR-Cas12a and enriched the transposon-inserted phages. For a pool of selected 10 open-reading frames (2 known functional protein genes and 8 hypothetical protein genes) of phage S1, we identified 5 (2 known functional protein genes and 3 hypothetical protein genes) as indispensable genes and the remaining 5 (all hypothetical protein genes) as dispensable genes. This approach offers a convenient, site-specific method that does not depend on homologous arms and double-strand breaks (DSBs), holding promise for future applications across a broader range of phages and facilitating the identification of the importance of phage genes and the insertion of genetic cargos.

IncA/C plasmid encoding blaCTX-M-55 in non-O1 Vibrio cholerae isolates from the edible river fish Mastacembelus sp.

Extended-spectrum ß-lactamase-producing non-O1 Vibrio cholerae was isolated from edible Mastacembelus sp. in Vietnam. The genome sequence was sequenced using DNBSEQ-G400 and MinION Mk1b. A plasmid of approximately 183-kb encoding blaCTX-M-55 and blaTEM-1 was detected.

Magnetic chitin beads (MCB) coated with Vibrio cholerae reveals transcriptome dynamics in adult mice with a complex gut microbiota.

Vibrio cholerae adapts to the host environment by altering gene expression. Because of the complexity of the gut microbiome, current in vivo V. cholerae transcriptome studies have focused on microbiota-undeveloped conditions, neglecting the interaction between the host's commensal gut microbiota and V. cholerae. In this study, we analyzed the transcriptome of fully colonized adult mice in vivo using V. cholerae coated-magnetic chitin beads (vcMCB). This provides a simple yet powerful method for obtaining high-quality RNA from V. cholerae during colonization in mice. The transcriptome of V. cholerae recovered from adult mice infected with vcMCB shows differential expression of several genes when compared to V. cholerae recovered from the infant mouse and infant rabbit model. Some of these genes were also observed to be differentially expressed in previous studies of V. cholera recovered from human infection when compared to V. cholerae grown in vitro. In particular, we confirmed that V. cholerae resists the inhibitory effects of low pH and formic acid from gut microbiota, such as Anaerostipes caccae and Dorea formicigenerans, by downregulating vc1080. We propose that the vc1080 product may protect V. cholerae from formic acid stress through a novel acid tolerance response mechanism. Transcriptomic data obtained using the vcMCB system provide new perspectives on the interaction between V. cholerae and the gut microbiota, and this approach can also be applied to studies of other pathogenic bacteria.

Cholera outbreak in 2022 among children in Karachi: Study of cases attending to a Tertiary Care Hospital.

Objective & Background: Repeated outbreaks of cholera have occurred in Karachi. Changing patterns in seasonality, serotypes and antibiotic resistance have been observed in these outbreaks. Recently, in the year 2022, a surge of cholera cases has been reported from Karachi during the months of April-June. This study aimed to identify clinical features, antibiotic susceptibility, complications, and response to treatment of V. cholerae infection among children attending Indus hospital, Karachi. Methods: A retrospective chart review of pediatric patients was conducted for children aged 0-16 years. All children treated for culture-proven cholera infection at Indus Hospital from March to June 2022 were included. Details of clinical features, complications, antibiotic susceptibility, and response to treatment were retrieved from the health management information system (HMIS) of the hospital. Results: Twenty children were included. The median age was 01 (0.50-3.75) years. There were 9 (45%) males and 11 (55%) females. All the culture isolates belonged to serogroup O1 Ogawa of the Vibrio cholerae. Vomiting and diarrhea were the most common symptoms. Dehydration, acute kidney injury, and shock were seen in 19 (95%), 6 (30%), and 2 (10%) children respectively. Eleven children were admitted with an average hospital stay of 5 (Median-IQR 3-6) days. The isolates were completely susceptible to tetracycline, ciprofloxacin, and azithromycin. Different antibiotics were given which included cefotaxime, ceftriaxone, doxycycline, and ciprofloxacin. All children responded completely to the antibiotics. Conclusion: In present study all V. cholerae isolates belonged to the O1 Ogawa serotype that showed complete susceptibility to tetracycline, ciprofloxacin, and azithromycin. Dehydration, electrolyte imbalance, and renal impairment were the most common complications observed. Drinking unboiled water was identified as a potential source of cholera in most children. Therefore, advocacy of hygienic practices and disinfection of water supplies is recommended to prevent future cholera outbreaks.

Macrophytes and their wrack as a habitat for faecal indicator bacteria and Vibrio in coastal marine environments.

Waterborne pathogenic bacteria, including faecal indicator bacteria and potentially pathogenic Vibrio, are a global concern for diseases transmitted through water. A systematic review was conducted to analyse publications that investigated these bacteria in relation to macrophytes (seagrasses and macroalgae) in coastal marine environments. The highest quantities of FIB were found on brown algae and seagrasses, and the highest quantities of Vibrio bacteria were on red algae. The most extensively studied macrophyte group was brown algae, green algae were the least researched. Macrophyte wrack was found to favor the presence of FIB, but there is a lack of information about Vibrio quantities in this environment. To understand the role of Vibrio bacteria that are pathogenic to humans, molecular methods complementary to cultivation methods should be used. Further research is needed to understand the underlying mechanisms of FIB and potentially pathogenic Vibrio with macrophytes and their microbiome in the coastal marine environment.

An efficient DNAzyme for the fluorescence detection of Vibrio cholerae.

Vibrio cholerae (Vc) causes cholera disease. Vc contamination is widely found in water and aquatic products, and therefore is a serious food safety concern, especially for the seafood industry. In this paper, we attempted the rapid detection of V. cholerae. Nine rounds of in vitro selection using an unmodified DNA library were successfully performed to find specific DNAzymes of Vc. Their activity was evaluated based on a fluorescence assay and gel electrophoresis. Finally, a DNAzyme (named DVc1) with good activity and specificity with a detection limit of 7.2 × 103 CFU/mL of Vc was selected. A simple biosensor was constructed by immobilizing DVc1 and its substrate in shallow circular wells of a 96-well plate using pullulan polysaccharide and trehalose. When the crude extracellular mixture of Vc was added to the detection wells, the fluorescent signal was observed within 20 min. The sensor effectively detected Vc in aquatic products indicating its simplicity and efficiency. This sensitive DNAzyme sensor can be a rapid onsite Vc detection tool.

Antibiotic-Resistant Vibrio cholerae O1 and Its SXT Elements Associated with Two Cholera Epidemics in Kenya in 2007 to 2010 and 2015 to 2016.

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.

Spectrum of ctxB genotypes, antibiogram profiles and virulence genes of Vibrio cholerae serogroups isolated from environmental water sources from Odisha, India.

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 ctxB 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 ctxB1, ctxB3 and ctxB7 genotypes. However, only ctxB1 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.

Sequential outbreaks due to mixed ctxB alleles of Vibrio cholerae O1 in Mayurbhanj district of Odisha, India.

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.

Serotype conversion gene rfbT is directly regulated by histone-like nucleoid structuring protein (H-NS) in V. cholerae O1.

Vibrio cholerae serogroup O1 (V. cholerae O1) is closely associated with cholera epidemics and has two main immunologically distinguishable serotypes, Ogawa and Inaba. Isolates serotype as Ogawa if the O-antigen polysaccharide (O-PS) is methylated or as Inaba if the O-PS is not methylated. This methylation is mediated by a methyltransferase encoded by the rfbT gene, and the mutation and low expression of rfbT results in serotype switch from Ogawa to Inaba. Previously, we have shown that cAMP receptor protein (CRP) activates rfbT. In this study, we demonstrated that histone-like nucleoid structuring protein (H-NS) is directly involved in the transcriptional repression of rfbT. This finding is supported by the analyses of rfbT mRNA level, rfbT-lux reporter fusions, electrophoretic mobility shift assay (EMSA), and DNase I footprinting assay. The rfbT mRNA abundances were significantly increased by deleting hns rather than fis which also preferentially associates with AT-rich sequences. A single-copy chromosomal complement of hns partly restored the down-regulation of rfbT. Analysis of rfbT-lux reporter fusions validated the transcriptional repression of hns. Subsequent EMSA and DNase I footprinting assay confirmed the direct binding of H-NS to rfbT promoter and mapped the exact binding site which was further verified by site-directed mutagenesis and promoter functional analysis. Furthermore, we found that in hns deletion mutant, CRP is no longer required for transcriptionally activating rfbT, suggesting that CRP functions as a dedicated transcription factor to relieve H-NS repression at rfbT. Together, this study expanded our understanding of the genetic regulatory mechanism of serotype conversion by global regulators in V. cholerae O1.

Environmental Drivers of Vibrio cholerae Abundances in Mobile Bay, Alabama.

Vibrio cholerae is the etiological agent of the illness cholera. However, there are non-O1/non-O139 V. cholerae (NOVC) strains that generally lack the toxin gene (ctx) and colonization factors that cause cholera. These NOVC strains are autochthonous members of estuarine environments and a significant cause of seafood-borne gastroenteritis in the United States. The objective of this study was to identify environmental parameters that correlate with NOVC prevalence in oysters, water, and sediment at three ecologically diverse locations in Mobile Bay, AL, including Dog River (DR), Fowl River (FR), and Cedar Point (CP). Oyster, water, and sediment samples were collected twice a month when conditions were favorable for NOVC growth and once a month when they were not. A most probable number (MPN)/real-time PCR assay was used to determine NOVC abundances. Environmental parameters were measured during sampling to determine their relationship, if any, with NOVC at each site. NOVC abundances in oysters at DR, FR, and CP were 0.87, 0.87, and -0.13 log MPN/g, respectively. In water, the median NOVC levels at DR, FR, and CP were 1.18, -0.13, and -0.82 log MPN/mL, and in sediment, the levels were 1.48, 1.87, and -0.03 log MPN/g, respectively. Correlations of NOVC abundances in oyster, water, and sediment samples with environmental parameters were largely site specific. For example, the levels of NOVC in oysters at DR had a positive correlation with temperature but a negative correlation with dissolved oxygen (DO) and nutrient concentrations, NO2-, NO3-, dissolved inorganic nitrogen (DIN), total dissolved nitrogen (TDN), and dissolved inorganic phosphorus (DIP). At FR, however, the levels of NOVC in oysters displayed only a negative correlation with NO2-. When grouping NOVC abundances by temperature, the main driving factor for prevalence, additional correlations with salinity, total cell counts, dissolved organic nitrogen (DON), and dissolved organic carbon (DOC) became evident regardless of the site. IMPORTANCE NOVC can cause gastrointestinal illness in humans, which typically occurs after the consumption of raw or undercooked seafood. Incidence rates of NOVC gastroenteritis have increased during the past decade. In this study, NOVC was enumerated from oysters, sediment, and water collected at three sites in Mobile Bay, with environmental parameters measured concurrently over the course of a year, to identify potential environmental drivers of NOVC abundances. The data from this study, from an area lacking in V. cholerae research, provide a useful baseline for risk analysis of V. cholerae infections. Defining correlations between NOVC and environmental attributes at different sites and temperatures within a dynamic system such as Mobile Bay provides valuable data to better understand the occurrence and proliferation of V. cholerae in the environment.

Antimicrobial resistance among clinical Vibrio cholerae non-O1/non-O139 isolates: systematic review and meta-analysis.

Non-O1/non-O139 Vibrio cholerae (NOVC) are nonpathogenic or asymptomatic colonizers in humans, but they may be related to intestinal or extra-intestinal (severe wound infections or sepsis) infections in immunocompromised patients.The present study aimed to evaluate the weighted pooled resistance (WPR) rates in clinical NOVC isolates based on different years, areas, quality, antimicrobial susceptibility testing (AST), and resistance rates. We systematically searched the articles in PubMed, Scopus, and Embase (until January 2020). Data analyses were performed using the Stata software program (version 17). A total of 16 studies that had investigated 824 clinical NOVC isolates were included in the meta-analysis. The majority of the studies were conducted in Asia (n = 14) and followed by Africa (n = 2). The WPR rates were as follows: erythromycin 10%, ciprofloxacin 5%, cotrimoxazole 27%, and tetracycline 13%. There was an increase in resistance to ciprofloxacin, nalidixic acid, and gentamicin, norfloxacin during the period from 2000 to 2020. On the contrary, there was a decreased resistance to erythromycin, tetracycline, chloramphenicol, cotrimoxazole, ampicillin, streptomycin, kanamycin, and neomycin during the period from 2000 to 2020. The lowest resistance rate were related to gentamicin, kanamycin, ciprofloxacin, and chloramphenicol against NOVC strains. However, temporal changes in antimicrobial resistance rate were found in our study. We established continuous surveillance, careful appropriate AST, and limitations on improper antibiotic usage, which are essential, especially in low-income countries.

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%; df=332=1755.09,Qp=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.

Molecular Epidemiology of Antimicrobial Resistance and Virulence Profiles of Escherichia coli, Salmonella spp., and Vibrio spp. Isolated from Coastal Seawater for Aquaculture.

The occurrence of waterborne antimicrobial-resistant (AMR) bacteria in areas of high-density oyster cultivation is an ongoing environmental and public health threat given the popularity of shellfish consumption, water-related human recreation throughout coastal Thailand, and the geographical expansion of Thailand's shellfish industry. This study characterized the association of phenotypic and genotypic AMR, including extended-spectrum ß-lactamase (ESBL) production, and virulence genes isolated from waterborne Escherichia coli (E. coli) (n = 84), Salmonella enterica (S. enterica) subsp. enterica (n = 12), Vibrio parahaemolyticus (V. parahaemolyticus) (n = 249), and Vibrio cholerae (V. cholerae) (n = 39) from Thailand's coastal aquaculture regions. All Salmonella (100.0%) and half of V. cholerae (51.3%) isolates harbored their unique virulence gene, invA and ompW, respectively. The majority of isolates of V. parahaemolyticus and E. coli, ~25% of S. enterica subsp. enterica, and ~12% of V. cholerae, exhibited phenotypic AMR to multiple antimicrobials, with 8.9% of all coastal water isolates exhibiting multidrug resistance (MDR). Taken together, we recommend that coastal water quality surveillance programs include monitoring for bacterial AMR for food safety and recreational water exposure to water for Thailand's coastal water resources.

Heterogeneous Growth Enhancement of Vibrio cholerae in the Presence of Different Phytoplankton Species.

Vibrio cholerae is a ubiquitously distributed human pathogen that naturally inhabits marine and estuarine ecosystems. Two serogroups are responsible for causing cholera epidemics, O1 and O139, but several non-O1 and non-O139 V. cholerae (NOVC) strains can induce cholera-like infections. Outbreaks of V. cholerae have previously been correlated with phytoplankton blooms; however, links to specific phytoplankton species have not been resolved. Here, the growth of a NOVC strain (S24) was measured in the presence of different phytoplankton species, alongside phytoplankton abundance and concentrations of dissolved organic carbon (DOC). During 14-day experiments, V. cholerae S24 was cocultured with strains of the axenic phytoplankton species Actinocyclus curvatulus, Cylindrotheca closterium, a Pseudoscourfieldia sp., and a Picochlorum sp. V. cholerae abundances significantly increased in the presence of A. curvatulus, C. closterium, and the Pseudoscourfieldia sp., whereas abundances significantly decreased in the Picochlorum sp. coculture. V. cholerae growth was significantly enhanced throughout the cogrowth experiment with A. curvatulus, whereas when grown with C. closterium and the Pseudoscourfieldia sp., growth only occurred during the late stationary phase of the phytoplankton growth cycle, potentially coinciding with a release of DOC from senescent phytoplankton cells. In each of these cases, significant correlations between phytoplankton-derived DOC and V. cholerae cell abundances occurred. Notably, the presence of V. cholerae also promoted the growth of A. curvatulus and Picochlorum spp., highlighting potential ecological interactions. Variations in abundances of NOVC identified here highlight the potential diversity in V. cholerae-phytoplankton ecological interactions, which may inform efforts to predict outbreaks of NOVC in coastal environments. IMPORTANCE Many environmental strains of V. cholerae do not cause cholera epidemics but remain a public health concern due to their roles in milder gastrointestinal illnesses. With emerging evidence that these infections are increasing due to climate change, determining the ecological drivers that enable outbreaks of V. cholerae in coastal environments is becoming critical. Links have been established between V. cholerae abundance and chlorophyll a levels, but the ecological relationships between V. cholerae and specific phytoplankton species are unclear. Our research demonstrated that an environmental strain of V. cholerae (serogroup 24) displays highly heterogenous interactions in the presence of different phytoplankton species with a relationship to the dissolved organic carbon released by the phytoplankton species. This research points toward the complexity of the interactions of environmental strains of V. cholerae with phytoplankton communities, which we argue should be considered in predicting outbreaks of this pathogen.