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Frontiers in Microbiology 2021Water resources contaminated with pathogenic species are usually a source of devastating infection outbreaks that have been a public health concern in both developed...
Water resources contaminated with pathogenic species are usually a source of devastating infection outbreaks that have been a public health concern in both developed and developing countries over the decades. The present study assessed the prevalence of six medically significant species in some water resources in Eastern Cape Province, South Africa for 12 months. We detected vibrios in all the 194 water samples analyzed using polymerase chain reaction (PCR). The prevalence of , , , , , and in freshwater samples was 34, 19, 9, 2, 3, and 2%, and that in brackish water samples was 44, 28, 10, 7, 46, and 51%, respectively. The population of the presumptive spp. isolated from freshwater (628) and brackish water (342) samples that were confirmed by PCR was 79% (497/628) and 85% (291/342), respectively. Twenty-two percent of the PCR-confirmed isolates from freshwater ( = 497) samples and 41% of the PCR-confirmed isolates from brackish water samples ( = 291) fall among the species of interest. The incidences of , , , , , and amidst these spp. of interest that were recovered from freshwater samples were 75, 14, 4, 6, 1, and 1%, whereas those from brackish water samples were 24, 7, 3, 3, 47, and 18%, respectively. Our observation during the study suggests pollution as the reason for the unusual isolation of medically important vibrios in winter. Correlation analysis revealed that temperature drives the frequency of isolation, whereas salinity drives the composition of the targeted species at our sampling sites. The finding of the study is of public health importance going by the usefulness of the water resources investigated. Although controlling and preventing most of the factors that contribute to the prevalence of medically important bacteria, such as species, at the sampling points might be difficult, regular monitoring for creating health risk awareness will go a long way to prevent possible -related infection outbreaks at the sampling sites and their immediate environment.
PubMed: 34149632
DOI: 10.3389/fmicb.2021.617703 -
Frontiers in Microbiology 2021Bacterial pathogens are a major cause of infectious diseases in aquatic animals. The abuse of antibiotics in the aquatic industry has led to the proliferation of...
Bacterial pathogens are a major cause of infectious diseases in aquatic animals. The abuse of antibiotics in the aquatic industry has led to the proliferation of antibiotic resistance. It is therefore essential to develop more effective and safer strategies to increase the efficacy and extend the life span of the antibiotics used in aquaculture. In this study, we show that six aquaculture bacterial pathogens (i.e., , , , , , and ) in the stationary phase can be rapidly killed after immersion in gentamicin- or neomycin-containing, ion-free solutions for a few minutes. Such hypoionic shock treatment enhances the bacterial uptake of gentamicin in an ATP-dependent manner. Importantly, we demonstrate, as a proof of concept, that gentamicin under hypoionic shock conditions can effectively kill in a skin infection model of zebrafish (), completely curing the infected fish. Given that pathogenic bacteria generally adhere to the skin surface and gills of aquatic animals, our strategy is of potential significance for bacterial infection control, especially for small-scale economic fish farming and ornamental fish farming. Further, the combined treatment can be completed within 5 min with a relatively small volume of solution, thus minimizing the amount of residual antibiotics in both animals and the environment.
PubMed: 33889141
DOI: 10.3389/fmicb.2021.641846 -
Emerging Microbes & Infections Dec 2021is an emerging enteric pathogen of increasing public health threat. Two quorum sensing (QS) systems, VfqI-VfqR and CqsA/LuxS-HapR, and two type VI secretion systems...
is an emerging enteric pathogen of increasing public health threat. Two quorum sensing (QS) systems, VfqI-VfqR and CqsA/LuxS-HapR, and two type VI secretion systems (T6SSs), VflT6SS1 and VflT6SS2, have been identified in . Whether there exists any correlation between the two systems is unclear. In this study, we found that CqsA/LuxS-HapR circuit regulator LuxO represses while HapR activates VflT6SS2. The effect of LuxO is more pronounced at low cell density and is HapR-dependent. Deletion of abolished Hcp expression and alleviated antibacterial virulence. However, these effects were rescued by HapR-expressing plasmid. Reporter fusion analyses showed that HapR is required for the promoter activities of VflT6SS2. Sequence inspection of the major cluster promoter revealed two potential Motif 1 HapR binding sites, and their bindings to HapR were confirmed by both electrophoretic mobility shift assay (EMSA) and DNase I footprinting assay. Meanwhile, two single Motif 2 sites were identified in 2_a (A) and 2_b (B) promoter regions of the orphan cluster which are less conserved and displayed lower affinities to HapR. Together, our study demonstrated that CqsA/LuxS-HapR QS manipulate VflT6SS2 in , and this finding will enhance our understanding of possible crosstalk between T6SS and QS in microbes.
Topics: Amino Acid Motifs; Bacterial Proteins; Binding Sites; DNA-Binding Proteins; Gene Expression Regulation, Bacterial; Genetic Complementation Test; Mutation; Promoter Regions, Genetic; Quorum Sensing; RNA, Bacterial; Repressor Proteins; Trans-Activators; Type VI Secretion Systems; Vibrio; Virulence
PubMed: 33689580
DOI: 10.1080/22221751.2021.1902244 -
Antibiotics (Basel, Switzerland) Feb 2021Cyadox has potential use as an antimicrobial agent in animals. However, its pharmacodynamic properties have not been systematically studied yet. In this study, the in...
Cyadox has potential use as an antimicrobial agent in animals. However, its pharmacodynamic properties have not been systematically studied yet. In this study, the in vitro antibacterial activities of cyadox were assayed, and the antibacterial efficacy of cyadox against facultative anaerobes was also determined under anaerobic conditions. It was shown that and (MIC = 0.25 and 1 μg/mL) from pigs, and from poultry, , spp., and from fish were highly susceptible to cyadox (MIC= 1 and 8 μg/mL). However, has no killing effect for drug tolerance. Under in vitro anaerobic conditions, the antibacterial activity of cyadox against most facultative anaerobes was considerably enhanced Under anaerobic conditions for the facultative anaerobes, susceptible bacteria were , . (including , , , , and , excluding ), , spp. (including , , and ), , , , , , and (MICs were 0.25~8 μg/mL, MBCs were 1-64 μg/mL). Intermediate bacteria were spp. (including and ), , and spp. (MICs mainly were 8~32 μg/mL, MBCs were 16~128 μg/mL). This study firstly showed that cyadox had strong antibacterial activity and had the potential to be used as a single drug in the treatment of bacterial infectious diseases.
PubMed: 33546407
DOI: 10.3390/antibiotics10020153 -
Microbiology (Reading, England) Nov 2020the aetiological agent of cholera, possesses multiple iron acquisition systems, including those for the transport of siderophores. How these systems benefit in...
the aetiological agent of cholera, possesses multiple iron acquisition systems, including those for the transport of siderophores. How these systems benefit in low-iron, polymicrobial communities in environmental settings or during infection remains poorly understood. Here, we demonstrate that in iron-limiting conditions, co-culture of with a number of individual siderophore-producing microbes significantly promoted growth . We further show that in the host environment with low iron, colonizes better in adult mice in the presence of the siderophore-producing commensal . Taken together, our results suggest that in aquatic reservoirs or during infection, may overcome environmental and host iron restriction by hijacking siderophores from other microbes.
Topics: Animals; Bacterial Outer Membrane Proteins; Coculture Techniques; Enterobactin; Escherichia coli; Gastrointestinal Microbiome; Iron Deficiencies; Mice; Microbial Viability; Receptors, Cell Surface; Seawater; Siderophores; Vibrio cholerae
PubMed: 33074088
DOI: 10.1099/mic.0.000975 -
Frontiers in Microbiology 2020Agarose-oligosaccharide production from agar degradation by agarase exhibits lots of advantages and good application prospects. In this study, a novel agar-degrading...
Agarose-oligosaccharide production from agar degradation by agarase exhibits lots of advantages and good application prospects. In this study, a novel agar-degrading bacterium sp. A8 was isolated from a red algae in the South China Sea. The whole genome sequencing with comparative genomic and secretomic analysis were used to better understand its genetic components about agar degradation. This strain exhibited good agarase production in artificial seawater after culture optimization. The complete genome (4.88 Mb) of this strain comprised two circular chromosomes (3.19 and 1.69 Mb) containing 4,572 protein-coding genes, 108 tRNA genes and 31 rRNA genes. This strain was identified as A8 by comparative genomic analysis based on genome phylogenetic tree and average nucleotide identity (ANI) similarity. Different from other 20 similar strains including three strains of the same species, A8 possessed unique agar degradation ability with four β-agarases (GH50) and one α-1,3-L-NA2 hydrolase (GH117) due to the horizontal gene transfer. Secretomic analysis showed that only β-agarase (gene 3152) was abundantly expressed in the secretome of A8. This agarase had a good substrate specificity and wide work conditions in complex environments, suggesting its potential application for agarose-oligosaccharide production.
PubMed: 32849481
DOI: 10.3389/fmicb.2020.01934 -
Veterinary World Jun 2020bacteria are autochthonous inhabitants of aquatic and marine environments. Certain strains are responsible for important seafood-borne outbreaks in developed nations....
BACKGROUND AND AIM
bacteria are autochthonous inhabitants of aquatic and marine environments. Certain strains are responsible for important seafood-borne outbreaks in developed nations. The aim of this study was to investigate the occurrence of spp. along the Algerian Mediterranean coast in several samples of two prominent wild and farmed marine fishes, and .
MATERIALS AND METHODS
A total of 350 (n=280 farmed and n=70 wild) and 340 (n=250 farmed and n=90 wild) were sampled among three different locations along the Algerian Mediterranean coastal area. The samples were processed for research according to the ISO methods. Isolated colonies were identified utilizing biochemical tests and consecutively confirmed with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry, combined with polymerase chain reaction (PCR) analysis when appropriate, or confirmed with PCR analysis alone.
RESULTS
A total of 42 spp. were detected only among the farmed fishes. Taking into account, all 690 fishes sampled, the incidence of spp. was 6.08% (with peaks up to 7.92%) among the total number of farmed fishes. Overall, 25 strains were isolated from and 17 strains were isolated from . The isolated strains belonged to four different species and were represented as follows: (n=20), (n=15), (n=5), and (n=2). The incidence of was higher in places characterized by greater levels of anthropogenic contamination of seawater.
CONCLUSION
Considering the growing production and consequent rising consumption of farmed fish in Algeria, the reported incidence of and the presence of potentially pathogenic strains of such as cause particular concern for food safety matters. Even if innovative and natural techniques are desired in aquaculture, proper hygiene and manufacturing practices are essential for the correct management of infection risk in farmed fishes at both industrial and domestic levels.
PubMed: 32801574
DOI: 10.14202/vetworld.2020.1199-1208 -
Engineering in Life Sciences Oct 2019The increasing demand for freshwater and the continued depletion of available resources has led to a deepening global water crisis. Significant water consumption...
The increasing demand for freshwater and the continued depletion of available resources has led to a deepening global water crisis. Significant water consumption required by many biotechnological processes contributes to both the environmental and economic cost of this problem. Relatively few biocatalytic processes have been developed to utilize the more abundant supply of seawater, with seawater composition and salinity limiting its use with many mesophilic enzymes. We recently reported a salt tolerant ω-transaminase enzyme, Ad2-TAm, isolated from the genome of a halophilic bacterium, sp. CSM-2, from a Triassic period salt mine. In this study we aimed to demonstrate its applicability to biocatalytic reactions carried out in a seawater-based medium. Ad2-TAm was examined for its ability to aminate the industrially relevant substrate, furfural, in both seawater and freshwater-based reaction systems. Furfural was aminated with 53.6% conversion in a buffered seawater system, displaying improved function versus freshwater. Ad2-TAm outperformed the commonly employed commercial ω-TAms from and , both of which showed decreased conversion in seawater. Given the increasingly precarious availability of global freshwater, such applications of enzymes from halophiles have the ability to reduce demand for freshwater in large-scale industrial processes, delivering considerable environmental and economic benefits.
PubMed: 32624965
DOI: 10.1002/elsc.201900053 -
Open Forum Infectious Diseases Jun 2020is a foodborne pathogen known to cause a cholera-like gastroenteritis syndrome. Here we report the first case of liver abscess and bacteremia presumed to be from...
is a foodborne pathogen known to cause a cholera-like gastroenteritis syndrome. Here we report the first case of liver abscess and bacteremia presumed to be from sashimi, a Japanese raw seafood delicacy. We also provide a literature review of reported cases of extra-intestinal diseases including bacteremia.
PubMed: 32587879
DOI: 10.1093/ofid/ofaa212 -
Computational and Structural... 2019Transaminases (TAs) reversibly catalyze the transfer reaction of an amino group between an amino group donor and an amino group acceptor, using pyridoxal 5'-phosphate... (Review)
Review
Transaminases (TAs) reversibly catalyze the transfer reaction of an amino group between an amino group donor and an amino group acceptor, using pyridoxal 5'-phosphate (PLP) as a cofactor. TAs are categorized according to the amino group position of the donor substrate and respective TAs recognize their own specific substrates. Over the past decade, a number of TA structures have been determined by X-ray crystallography. On the basis of the structural information, the detailed mechanism of substrate recognition by TAs has also been elucidated. In this review, fold type I TAs are addressed intensively. Comparative studies on structural differences between the apo and holo forms of fold type I TAs have demonstrated that regions containing the active site exhibit structural plasticity in the apo form, facilitating PLP insertion into the active site. In addition, given that TAs recognize two different kinds of substrates, they possess dual substrate specificity. It is known that spatial rearrangements of active site residues occur upon binding of the substrates. Intriguingly, positively charged residues are predominantly distributed at the active site cavity. The electric field generated by such charge distributions may attract negatively charged molecules, such as PLP and amino group acceptors, into the active site. Indeed, TAs show remarkable dynamics in diverse aspects. In this review, we describe the comprehensive working mechanism of fold type I TAs, with a focus on conformational changes.
PubMed: 31452855
DOI: 10.1016/j.csbj.2019.07.007