OBJECTIVE: It is well recognized that only Vibrio cholerae O1 causes cholera pandemics. However, not all O1 strains cause pandemic-level disease. In this study, we analyzed non-pandemic O1 V. cholerae isolates from the 1960s to the 1990s from China and found that they fell into three lineages, one of which shared the most recent common ancestor with pandemic O1 strains. Each of these non-pandemic O1 lineages has unique properties that contribute to their capacity to cause cholera. The findings of this study enhanced our understanding of the emergence and evolution of both pandemic and non-pandemic O1 V. cholerae.

UNASSIGNED: Vibrio cholerae O1/O139 is responsible for cholera epidemics that remains a huge public health menace across the globe. Furthermore, an increasing resistance rate among V. cholerae strains has been reported around the world. Therefore, the objective of this meta-analysis was to evaluate the weighted pooled resistance (WPR) rates in clinical V. cholerae O1/O139 isolates based on different years, areas, antimicrobial susceptibility testing, and resistance rates.
UNASSIGNED: We searched the studies in PubMed, Scopus, Embase, and Web of Science (until January 2020). Statistical analyses were conducted using STATA software (ver. 14.0).
UNASSIGNED: A total of 139 studies investigating 24,062 V. cholerae O1/O139 isolates were analyzed. The majority of the studies originated in Asia (n = 102). The WPR rates were as follows: azithromycin 1%, erythromycin 36%, ciprofloxacin 3%, cotrimoxazole 79%, doxycycline 7%, and tetracycline 20%. There was increased resistance to cotrimoxazole, ciprofloxacin, and tetracycline during the 1980-2020 years.
UNASSIGNED: Temporal changes in antibiotic resistance rate found in this study demonstrated the critical continuous surveillance of antibiotic resistance. Also, ciprofloxacin, azithromycin, gentamicin, cephalexin, imipenem, ofloxacin, and norfloxacin were found to be the best antibiotics against V. cholera, with the highest and the lowest effectiveness resistance rate.

Objective: To analyze the etiological and epidemiological characteristics of Vibrio cholerae in Beijing during 2015-2021 and provide evidence for the prevention and control of cholera. Methods: The V. cholerae strains isolated in Beijing during 2015-2021 were analyzed by serotyping and virulence genes detection. Pulsed field gel electrophoresis (PFGE) was performed for the molecular typing of the strains. Based on the collected epidemiological and clinical data of cholera cases,the epidemiological characteristics of cholera were analyzed by descriptive epidemiology method. Results: A total of 76 Vibrio cholerae O1 strains were isolated in Beijing during 2015-2021, including 61 strains from human, 10 strains from environment and 5 strains from seafood. The 76 strains consisted of 68 Ogawa strains and 8 Inaba strains. Six Ogawa strains isolated from sporadic cases carried ctxAB. After NotⅠ digestion, 76 strains were divided into 33 PFGE patterns. From 2015 to 2021, a total of 38 cholera epidemics were reported in Beijing, most of them were sporadic ones, accounting for 92.11% (35/38). A total of 45 cases were reported, and the cases occurred during June-September accounted for 97.78% (44/45). Cholera cases occurred in 9 districts of Beijing, and the cases reported in Chaoyang district accounted for 42.22% (19/45) and in Changping district accounted for 31.11% (14/45). The age of the cholera cases ranged from 19 to 63 years. Except for one case with unknown clinical symptoms, 44 cases had diarrhea symptoms with 84.09% (37/44) of the cases reporting diarrhea (3-9 times/day), followed by yellow watery stool (95.45%, 42/44), abdominal pain (68.18%, 30/44), nausea and vomiting (40.91%, 18/44) and fever (36.36%, 16/44). Conclusion: Vibrio cholerae strains isolated in Beijing during 2015-2021 were mainly O1 serotype Ogawa,most of which were non-toxigenic. The PFGE of the strains varied. Cholera epidemics occurred in 9 districts of Beijing, but most were sporadic ones with incidence peak during June-September.
目的： 分析2015-2021年北京市霍乱弧菌的病原学和流行特征，为霍乱防控提供参考。 方法： 对北京市2015-2021年分离到的霍乱弧菌，进行血清分型、毒力基因检测和PFGE实验；对收集的霍乱病例流行病学和临床资料，用描述性流行病学方法分析其流行特征。 结果： 北京市2015-2021年共分离76株O1群霍乱弧菌（来源分别为人源性61株、环境涂抹10株和水产品5株），包括68株小川型菌株和8株稻叶型菌株，其中6株为O1群小川型菌株ctxAB基因阳性，均分离自散发病例。PFGE结果显示，76株分为33种带型。北京市2015-2021年共报告霍乱疫情38起，以散发疫情为主（92.11%，35/38）；累计报告病例45例，6-9月占97.78%（44/45）。北京市有9个行政区报告霍乱病例，朝阳区和昌平区分别占42.22%（19/45）和31.11%（14/45）；霍乱病例的年龄分布在19~63岁，44例病例均出现腹泻症状，1例临床症状不详。腹泻次数为3~9次/d的占84.09%（37/44）。临床症状中，出现黄色稀水样便、腹痛、恶心/呕吐和发热的分别占95.45%（42/44）、68.18%（30/44）、40.91%（18/44）和36.36%（16/44）。 结论： 2015-2021年北京市分离到的霍乱弧菌以O1群小川型为主，PFGE带型多样；北京市有9个行政区报告霍乱疫情，以散发为主，6-9月为疫情高峰。.

Vibrio cholerae O1/O139 were the predominant circulating serogroups exhibiting multi-drug resistance (MDR) during the cholera outbreak which led to cholera treatment failures.
This meta-analysis aimed to evaluate the weighted pooled resistance (WPR) rates in V. cholerae O1/O139 isolates obtained from environmental samples.
We systematically searched the articles in PubMed, Scopus, and Embase (until January 2020). Subgroup analyses were then employed by publication year, geographic areas, and the quality of studies. Statistical analyses were conducted using STATA software (ver. 14.0).
A total of 20 studies investigating 648 environmental V. cholerae O1/O139 isolates were analysed. The majority of the studies were originated from Asia (n = 9). In addition, a large number of studies (n = 15 i.e. 71.4%) included in the meta-analysis revealed the resistance to cotrimoxazole and ciprofloxacin. The WPR rates were as follows: cotrimoxazole 59%, erythromycin 28%, tetracycline 14%, doxycycline 5%, and ciprofloxacin 0%. There was increased resistance to nalidixic acid, cotrimoxazole, furazolidone, and tetracycline while a decreased resistance to amoxicillin, ciprofloxacin, erythromycin, chloramphenicol, ampicillin, streptomycin, and ceftriaxone was observed during the years 2000-2020. A significant decrease in the doxycycline and ciprofloxacin-resistance rates in V. cholerae O1/O139 isolates was reported over the years 2011-2020 which represents a decrease in 2001-2010 (p < 0.05).
Fluoroquinolones, gentamicin, ceftriaxone, doxycycline, kanamycin, and cefotaxime showed the highest effectiveness and the lowest resistance rate. However, the main interest is the rise of antimicrobial resistance in V. cholerae strains especially in low-income countries or endemic areas, and therefore, continuous surveillance, careful appropriate AST, and limitation on improper antibiotic usage are crucial.

There is a growing demand for rapid, sensitive, field-deployable nucleic acid tests for cholera, which usually occurs in rural areas. In this study, we developed a Cas12a-assisted rapid isothermal detection (CARID) system for the detection of toxigenic V. cholerae serogroups O1 and O139 by combining recombinase-aided amplification and CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins). The results can be determined by fluorescence signal and visualized by lateral flow dipstick. We identified 154 V. cholerae strains and 129 strains of other intestinal diarrheagenic bacteria with a 100% coincidence rate. The limit of detection of CARID was 20 copies/reaction of V. cholerae genomic DNA, which is comparable to that of polymerase chain reaction (PCR) and qPCR. Multiple-CARID was also established for efficiency and economic considerations with an acceptable decrease in sensitivity. Simulated sample tests showed that CARID is suitable for complex samples. In conclusion, CARID is a rapid, sensitive, economically efficient, and portable method for the detection of V. cholerae, which makes it suitable for field responses to cholera.

Prophage 919TP is widely distributed among Vibrio cholera and is induced to produce free φ919TP phage particles. However, the interactions between prophage φ919TP, the induced phage particle, and its host remain unknown. In particular, phage resistance mechanisms and potential fitness trade-offs, resulting from phage resistance, are unresolved. In this study, we examined a prophage 919TP-deleted variant of V. cholerae and its interaction with a modified lytic variant of the induced prophage (φ919TP cI-). Specifically, the phage-resistant mutant was isolated by challenging a prophage-deleted variant with lytic phage φ919TP cI-. Further, the comparative genomic analysis of wild-type and φ919TP cI--resistant mutant predicted that phage φ919TP cI- selects for phage-resistant mutants harboring a mutation in key steps of lipopolysaccharide (LPS) O-antigen biosynthesis, causing a single-base-pair deletion in gene gmd. Our study showed that the gmd-mediated O-antigen defect can cause pleiotropic phenotypes, e.g., cell autoaggregation and reduced swarming motility, emphasizing the role of phage-driven diversification in V. cholerae. The developed approach assists in the identification of genetic determinants of host specificity and is used to explore the molecular mechanism underlying phage-host interactions. Our findings contribute to the understanding of prophage-facilitated horizontal gene transfer and emphasize the potential for developing new strategies to optimize the use of phages in bacterial pathogen control.

Oligoribonuclease (Orn), a member of the DEDDh superfamily, can hydrolyse 2-5 nt nanoRNAs to mononucleotides. It is involved in maintaining the intracellular levels of RNA, c-di-GMP signalling and transcription initiation in many bacterial species. Here, the crystal structure of Orn from Vibrio cholerae O1 El Tor (VcOrn) is reported at a resolution of 1.7 Å. VcOrn, which consists of nine α-helices and six β-strands, crystallizes with a single monomer in the asymmetric unit but forms a homodimer via crystallographic twofold symmetry. Electron density is observed in the active pocket that corresponds to an intersubunit N-terminal expression tag with sequence GPLGSHHH. The positively charged N-terminal tag binds in the negatively charged nucleotide-binding pocket with a buried surface area of ∼500 Å2. The N-terminal tag interacts with VcOrn via π-π stacking with two conserved residues involved in nucleotide binding, as well as via salt bridges and hydrogen bonds. The structure reported here reveals that the active pocket can accommodate polypeptides in addition to nucleotides, thus providing an important starting point for investigation into substrate modification and inhibitor design targeting VcOrn.

The phosphoenolpyruvate (PEP): carbohydrate phosphotransferase system (PTS) allows bacteria to use various carbohydrates as energy resources including mannitol. The mannitol-specific PTS transporter in Vibrio cholerae is encoded by the mtlADR operon. Expression of the mtl operon has been shown to be strictly regulated by CRP, MtlS, and MtlR. In the present study, we investigated the regulation of mtlADR by the ferric uptake regulator (Fur). The results showed that Fur binds to the promoter-proximal DNA region of mtlADR to repress its transcription independent of iron, in mannitol-containing growth medium. The capacity for mannitol fermentation was significantly increased in Δfur relative to that of WT for normal and iron-replete growth media. The level of organic acids produced by Δfur was significantly enhanced relative to that produced by the WT strain in the normal and iron-replete media but not in an iron-starved medium. The results provided for a deeper understanding of the regulation of mtlADR in V. cholerae.

Determining the source and genetic characteristics of the imported pathogen is critical in the control of infectious diseases. Here, we reported the investigation of an imported cholera case in China in 2018 with a recent travel history in Nepal and India. Stool culture from the patient was identified as Vibrio cholerae serogroup O1, biotype El Tor, serotype Ogawa. The strain 2018HL24 possessed intact Vibrio seventh pandemic island I (VSP-I), Vibrio pathogenicity Island 1 and 2 (VPI-1, VPI-2). A VSP-II variant with a 13 kb deletion was also detected, which was identical to those observed in V. cholerae in cluster \"Nepal-4\". Phylogenetic analysis based on the core genome SNPs showed that the isolate was most closely related to the V. cholerae isolated in northern India not far from the border of Nepal in 2012 (16 SNPs). Combining the epidemiological data with phylogenetic analysis results, we speculate that the patient may got infected in Nepal-India region.

Vibrio cholerae can enter a viable but non-culturable (VBNC) state when it encounters unfavourable environments; VBNC cells serve as important reservoirs and still pose threats to public health. The genetic regulation of V. cholerae entering its VBNC state is not well understood. Here, we show a confrontation strategy adapted by V. cholerae O1 in which it utilizes a quorum sensing (QS) system to prevent transition into a VBNC state under low nutrition and temperature conditions. The upregulation of hapR resulted in a prolonged culturable state of V. cholerae in artificial sea water at 4°C, whereas the mutation of hapR led to fast entry into the VBNC state. We also observed that different V. cholerae O1 natural isolates with distinct QS functions present a variety of abilities to maintain culturability during the transition to a VBNC state. The strain groups with higher or constitutive expression of QS genes exhibit a greater tendency to maintain the culturable state during VBNC induction than those lacking QS functional groups. In summary, HapR-mediated QS regulation is associated with the transition to the VBNC state in V. cholerae. HapR expression causes V. cholerae to resist VBNC induction and become dominant over competitors in changing environments.