Draft genome of Rosenbergiella nectarea strain 8N4T provides insights into the potential role of this species in its plant host.

Background:Rosenbergiella nectarea strain 8N4T, the type species of the genus Rosenbergiella, was isolated from Amygdalus communis (almond) floral nectar. Other strains of this species were isolated from the floral nectar of Citrus paradisi (grapefruit), Nicotiana glauca (tobacco tree) and from Asphodelus aestivus. R. nectarea strain 8N4T is a Gram-negative, oxidase-negative, facultatively anaerobic bacterium in the family Enterobacteriaceae. Results:Here we describe features of this organism, together with its genome sequence and annotation. The DNA GC content is 47.38%, the assembly size is 3,294,717 bp, and the total number of genes are 3,346. The genome discloses the possible role that this species may play in the plant. The genome contains both virulence genes, like pectin lyase and hemolysin, that may harm plant cells and genes that are predicted to produce volatile compounds that may impact the visitation rates by nectar consumers, such as pollinators and nectar thieves. Conclusions:The genome of R. nectarea strain 8N4T reveals a mutualistic interaction with the plant host and a possible effect on plant pollination and fitness

Antimicrobial Susceptibility of Environmental Non-O1/Non-O139 Vibrio cholerae Isolates

Vibrio cholerae serogroups O1 and O139 are the causative agents of cholera disease. There are more than 200 serogroups in this species that are termed V. cholerae non-O1/non-O139. Non-O1/non-O139 strains can cause gastroenteritis and cholera like diarrhea, wound infections, external otitis, and bacteraemia that may lead to mortality. Previous antimicrobial susceptibility studies were conducted mainly on O1/O139 serogroups and on clinical isolates. Our aim was to study and compare the antimicrobial susceptibilities of non-O1/non-O139 environmental strains isolated from chironomids, fish, and waterfowl. Significant differences were found in the antimicrobial susceptibilities between the environmental strains that were isolated from three different reservoir habitats. Significant increase in minimum inhibitory concentrations (MICs) of ampicillin and chloramphenicol was found in chironomid isolates from 2009 compared to those from 2005. V. cholerae isolates from different waterfowl species displayed the highest MIC values to chloramphenicol and trimethoprim-sulfamethoxazole (SXT), while chironomid isolates demonstrated the highest MIC values toward ampicillin. Isolates from fish and waterfowl showed high MIC values toward doxycycline. No significant differences were found between the MICs of isolates from the different waterfowl species. The percentage of antimicrobial resistance among V. cholerae isolates from waterfowl was the highest compared to the abundance of antimicrobial resistant isolates from chironomids or fish. The antimicrobial resistance genes can be carried on mobile genetic elements, thus, waterfowl may act as reservoirs for these elements and may spread them all over the globe. Data regarding treatment with antimicrobial agents toward V. cholerae non-O1/non-O139 serogroups is lacking and therefore further studies are needed

High quality draft genome sequence of Leucobacter chironomi strain MM2LBT (DSM 19883T) isolated from a Chironomus sp. egg mass

Leucobacter chironomi strain MM2LB(T) (Halpern et al., Int J Syst Evol Microbiol 59:665-70 2009) is a Gram-positive, rod shaped, non-motile, aerobic, chemoorganotroph bacterium. L. chironomi belongs to the family Microbacteriaceae, a family within the class Actinobacteria. Strain MM2LB(T) was isolated from a chironomid (Diptera; Chironomidae) egg mass that was sampled from a waste stabilization pond in northern Israel. In a phylogenetic tree based on 16S rRNA gene sequences, strain MM2LB(T) formed a distinct branch within the radiation encompassing the genus Leucobacter. Here we describe the features of this organism, together with the complete genome sequence and annotation. The DNA GC content is 69.90%. The chromosome length is 2,964,712 bp. It encodes 2,690 proteins and 61 RNA genes. L. chironomi genome is part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project

Accumulating evidence suggests that some waterbird species are potential vectors of Vibrio cholerae.

Vibrio cholerae is the causative agent of cholera, a life-threatening diarrheal disease. Cholera causes epidemics and pandemics, but the ways this disease spreads worldwide is still unclear. This review highlights a relatively new hypothesis regarding the way V. cholerae can be globally dispersed. Copepods and chironomids are natural reservoirs of V. cholerae and are part of different fish species' diet. Furthermore, V. cholerae inhabits marine and freshwater fish species. Waterbird species feed on fish or on small invertebrates such as copepods and chironomids. Waterbirds have also been found to carry living copepods and/or chironomids internally or externally from one waterbody to another. All of the above points to the fact that some waterbird species might be vectors of V. cholerae. Indeed, we and others have found evidence for the presence of V. cholerae non-O1 as well as O1 in waterbird cloacal swabs, feces, and intestine samples. Moreover, hand-reared cormorants that were fed on tilapia, a fish that naturally carries V. cholerae, became infected with this bacterial species, demonstrating that V. cholerae can be transferred to cormorants from their fish prey. Great cormorants as well as other waterbird species can cover distances of up to 1,000 km/day and thus may potentially transfer V. cholerae in a short time across and between continents. We hope this review will inspire further studies regarding the understanding of the waterbirds' role in the global dissemination of V. cholerae

Chironomus ramosus Larval Microbiome Composition Provides Evidence for the Presence of Detoxifying Enzymes

Chironomids (Diptera; Chironomidae) are aquatic insects that are abundant in freshwater. We aimed to study the endogenous microbiota composition of Chironomus ramosus larvae that were sampled from the Mutha River and a laboratory culture in India. Furthermore, we performed a metagenomic analysis of the larval microbiome, sampled from the Mutha River. Significant differences were found between the bacterial community composition of C. ramosus larvae that were sampled from the Mutha River and the laboratory culture. A total of 54.7% of the amplicon sequence variants (ASVs) that were identified in the larvae from the Mutha River were unique, compared to only 12.9% of unique ASVs that were identified from the laboratory-reared larvae. The four most abundant phyla across all samples were: Proteobacteria, Fusobacteria, Firmicutes, and Bacteroidetes, while the nine most abundant genera were: Aeromonas, Alkanindiges, Breznakia, Cetobacterium, Chryseobacterium, Desulfovibrio, Dysgonomonas, Thiothrix, and Vibrio. Moreover, in the metagenomic analysis, we detected bacterial genes and bacterial pathways that demonstrated the ability to degrade different toxic compounds, detoxify metal, and confer resistance to antibiotics and UV radiation, amongst other functions. The results illuminate the fact that there are detoxifying enzymes in the C. ramosus larval microbiome that possibly play a role in protecting the insect in polluted environments

Identification of chironomid species as natural reservoirs of toxigenic Vibrio cholerae strains with pandemic potential.

Vibrio cholerae causes the fatal cholera diarrhea. Chironomids (Diptera; Chironomidae) are abundant in freshwater aquatic habitats and estuaries and are natural reservoirs of V. cholerae. Until now, only the non-O1/O139 serogroups of V. cholerae were identified in chironomids. Here, we explored whether chironomids are natural reservoirs of V. cholerae O1/O139 serogroups, which are associated with cholera endemics and pandemics. All four life stages of chironomids were sampled from two rivers, and a laboratory culture in Pune, India, and from a pond in Israel. In total, we analyzed 223 chironomid samples. The presence of V. cholerae O1/O139 serogroups was verified using molecular tools. Nine chironomid species were identified; of them, Chironomus circumdatus was the most abundant. The presence of V. cholerae serogroup O1 and the cholera toxin genes were detected in samples from all chironomid species. However, serogroup O139 was detected in only two chironomid species. Besides PCR to detect specific genes, a metagenomic analysis that was performed in three selected C. ramosus larvae, identified a list of virulence genes associated with V. cholerae. The findings provide evidence that chironomids are natural reservoirs of toxigenic V. cholerae O1/O139. Chironomid populations and V. cholerae show biannual peak patterns. A similar pattern is found for cholera epidemics in the Bengal Delta region. Thus, we hypothesize that monitoring chironomids in endemic areas of the disease may provide a novel tool for predicting and preventing cholera epidemics. Moreover, serogroup O139 was detected only in two chironomid species that have a restricted distribution in the Indian subcontinent, possibly explaining why the distribution of the O139 serogroup is limited

Otitis Media Caused by V. cholerae O100: A Case Report and Review of the Literature

Infections due to Vibrio cholerae are rarely documented in Israel. Here we report a case of recurrent otitis media in a young male, caused by V. cholerae non-O1/O139. This extra-intestinal infection was caused by V. cholerae O100 and has been associated with freshwater exposure and travel. Symptoms of chronic periodic earaches along with purulent exudate began about one week after the patient suffered a water skiing accident on a river in Australia. The condition lasted for three years, until his ear exudate was examined in a clinical laboratory, diagnosed and treated. Five bacterial isolates were identified as V. cholerae O100. The isolates were screened for genetic characteristics and were found positive for the presence of hapA, hlyA, and ompU virulence genes. All isolates were negative for the presence of ctxA. Based on antibiogram susceptibility testing, ciprofloxacin ear drops were used until the patient’s symptoms disappeared. This case demonstrates that exposure to freshwater can cause otitis media by V. cholerae non-O1/O139 in young and otherwise healthy humans

Table_1_Antimicrobial Susceptibility of Environmental Non-O1/Non-O139 Vibrio cholerae Isolates.pdf

<p>Vibrio cholerae serogroups O1 and O139 are the causative agents of cholera disease. There are more than 200 serogroups in this species that are termed V. cholerae non-O1/non-O139. Non-O1/non-O139 strains can cause gastroenteritis and cholera like diarrhea, wound infections, external otitis, and bacteraemia that may lead to mortality. Previous antimicrobial susceptibility studies were conducted mainly on O1/O139 serogroups and on clinical isolates. Our aim was to study and compare the antimicrobial susceptibilities of non-O1/non-O139 environmental strains isolated from chironomids, fish, and waterfowl. Significant differences were found in the antimicrobial susceptibilities between the environmental strains that were isolated from three different reservoir habitats. Significant increase in minimum inhibitory concentrations (MICs) of ampicillin and chloramphenicol was found in chironomid isolates from 2009 compared to those from 2005. V. cholerae isolates from different waterfowl species displayed the highest MIC values to chloramphenicol and trimethoprim-sulfamethoxazole (SXT), while chironomid isolates demonstrated the highest MIC values toward ampicillin. Isolates from fish and waterfowl showed high MIC values toward doxycycline. No significant differences were found between the MICs of isolates from the different waterfowl species. The percentage of antimicrobial resistance among V. cholerae isolates from waterfowl was the highest compared to the abundance of antimicrobial resistant isolates from chironomids or fish. The antimicrobial resistance genes can be carried on mobile genetic elements, thus, waterfowl may act as reservoirs for these elements and may spread them all over the globe. Data regarding treatment with antimicrobial agents toward V. cholerae non-O1/non-O139 serogroups is lacking and therefore further studies are needed.</p