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Open Forum Infectious Diseases Dec 2023The genus is increasingly implicated in human infections, but knowledge of its clinical characteristics and antimicrobial resistance profiles has been limited owing to...
BACKGROUND
The genus is increasingly implicated in human infections, but knowledge of its clinical characteristics and antimicrobial resistance profiles has been limited owing to its complex taxonomy.
METHODS
We conducted a multicenter prospective cohort study of patients with infections at hospitals across Japan. Patients were eligible for inclusion if they had an spp. strain in a clinical culture and were considered infected at the culture site. Clinical data were collected, and isolates underwent susceptibility testing and whole-genome sequencing.
RESULTS
A total of 144 patients were included. Hepatobiliary infection accounted for a majority of infections (73% [105 of 144]), which mostly occurred in elderly patients with comorbid conditions, including hepatobiliary complications. The all-cause 30-day mortality rate was 10.0% (95% confidence interval, 4.9%-14.8%). By whole-genome sequencing, 141 strains (98%) belonged to 4 species, , , and with significant intraspecies diversity. was predominant in all infection sites except skin and soft tissue, for which was the prevailing species. The genes encoding chromosomally mediated class B, C, and D β-lactamases were harbored by 92%-100% of the isolates in a species-specific manner, but they often lacked association with resistance phenotypes. The activity of cefepime was reliable. All isolates of and carried an like colistin resistance gene and showed reduced susceptibility to colistin.
CONCLUSIONS
Hepatobiliary tract was the most common infection site of spp., with being the dominant causative species. The resistance genotype and phenotype were often incongruent for β-lactam agents.
PubMed: 38156048
DOI: 10.1093/ofid/ofad587 -
Open Veterinary Journal Jan 2024The high summer mortality in many fish farms, which had detrimental economic and social implications, was a serious challenge that the fish industry had to deal with.
BACKGROUND
The high summer mortality in many fish farms, which had detrimental economic and social implications, was a serious challenge that the fish industry had to deal with.
AIM
With an examination of the most effective antibiotic, the ongoing research was intended to shed light on the identification of the main bacterial pathogens associated with the summer mortality syndrome in the diseased farmed Nile tilapia.
METHODS
Six hundred dead Nile tilapia samples that had suffered from summer mortality were collected from several fish farms between May and October of 2022. The gathered fish displayed hemorrhagic areas on the skin, scale detachment, fin degeneration, erosions, skin ulcers, and corneal opacity with unilateral and/or bilateral exophthalmia. The most prominent internal appearance was swelling of the internal organs with sanguineous ascetic fluid.
RESULTS
There were 225 bacterial isolates found. Six species were identified through phenotypic and biochemical analysis; they were , o, , , , and spp., in descending percentage, respectively. spp., spp., and spp. were the three most frequent isolated bacterial pathogens. The identification of , spp., and , the three most common bacterial isolates, was confirmed by molecular analysis by polymerase chain reaction. Most of the tested strains were found to be responsive to Ciprofloxacin (CIP), Gentamicin (CN), and Chloramphenicol (C) but resistant to Amoxicillin (AMX), according to an antibiotic sensitivity test.
CONCLUSION
The three most dangerous common bacterial infections discovered during mass-farmed tilapia summer mortality are , sp., and . This makes it clear that high water temperatures may raise the possibility of bacterial infections, which could cause widespread tilapia mortality and substantial financial losses. Therefore, it is crucial to maintain a beneficial fish culture, environment, and husbandry practices to enhance the tilapia-rearing environment and lessen the virulence of the disease. Isolated bacterial strains showed low levels of resistance to AMX but were vulnerable to CIP, CN, and C.
Topics: Animals; Cichlids; Streptococcus; Anti-Bacterial Agents; Virulence; Bacterial Infections
PubMed: 38633195
DOI: 10.5455/OVJ.2024.v14.i1.7 -
Microbiome Jul 2023For more than a century, the Koch's postulates have been the golden rule for determining the causative agents in diseases. However, in cases of multiple pathogens-one...
BACKGROUND
For more than a century, the Koch's postulates have been the golden rule for determining the causative agents in diseases. However, in cases of multiple pathogens-one disease, in which different pathogens can cause the same disease, the selection of microorganisms that regress infection is hard when Koch's postulates are applied. Microbiome approaches can obtain relatively complete information about disease-related microorganisms and can guide the selection of target microorganisms for regression infection. In the present study, whitish muscle syndrome (WMS) of Scylla paramamosain, which has typical symptoms with whitish muscle and blackened hemolymph was used as an example to establish a new research strategy that integrates microbiome approaches and Koch's postulates to determinate causative agents of multiple pathogens-one disease.
RESULTS
Microbiome results revealed that Aeromonas, Acinetobacter, Shewanella, Chryseomicrobium, Exiguobacterium, Vibrio and Flavobacterium, and Kurtzmaniella in hemolymph were bacterial and fungal indicators for WMS. A total of 23 bacteria and 14 fungi were isolated from hemolymph and muscle tissues, and among the bacteria, Shewanella chilikensis, S. xiamenensis, Vibrio alginolyticus, S. putrefaciens, V. fluvialis, and V. parahaemolyticus were present in hemolymph and/or muscle tissues in each WMS crab, and the last three species were also present in three Healthy crabs. The target bacteria and fungi were further screened to regression infections based on two criteria: whether they belonged to the indicator genera for WMS, whether they were isolated from both hemolymph and muscle tissues in most WMS crabs. Only S. chilikensis, S. putrefaciens, S. xiamenensis, V. alginolyticus, V. fluvialis, and V. parahaemolyticus met both two criteria. The six bacteria that met both two criteria and six fungi and another bacterium that unmatched any of two criteria were used to perform regression infection experiments based on Koch's postulates. S. chilikensis, S. putrefaciens, S. xiamenensis, V. alginolyticus, V. fluvialis, and V. parahaemolyticus met both two criteria, and the results indicate that they cause WMS in crabs independently.
CONCLUSIONS
This study fully demonstrated that our research strategy that integrates the microbiome and Koch's postulates can maximize the ability to catch pathogens in one net for the situation of multiple pathogens-one disease. Video Abstract.
Topics: Animals; Brachyura; Vibrio; Microbiota; Muscles
PubMed: 37475003
DOI: 10.1186/s40168-023-01570-6 -
Applied Microbiology and Biotechnology Dec 2023Bacterial polyhydroxyalkanoates (PHAs) are promising bio-based biodegradable polyesters. It was recently reported that novel PHA block copolymers composed of...
Bacterial polyhydroxyalkanoates (PHAs) are promising bio-based biodegradable polyesters. It was recently reported that novel PHA block copolymers composed of (R)-3-hydroxybutyrate (3HB) and (R)-2-hydroxybutyrate (2HB) were synthesized by Escherichia coli expressing PhaC, a chimeric enzyme of PHA synthases derived from Aeromonas caviae and Ralstonia eutropha. In this study, the sequence-regulating PhaC was applied in the natural PHA-producing bacterium, R. eutropha. During the investigation, (R/S)-2HB was found to exhibit strong growth inhibitory effects on the cells of R. eutropha. This was probably due to formation of excess 2-ketobutyrate (2KB) from (R/S)-2HB and the consequent L-valine depletion caused by dominant L-isoleucine synthesis attributed to the excess 2KB. Deletion analyses for genes of lactate dehydrogenase homologs identified cytochrome-dependent D-lactate dehydrogenase (Dld) and [Fe-S] protein-dependent L-lactate dehydrogenase as the enzymes responsible for sensitivity to (R)-2HB and (S)-2HB, respectively. The engineered R. eutropha strain (phaC, ldhA-hadA encoding clostridial (R)-2-hydroxyisocaproate dehydrogenase and (R)-2-hydoroxyisocaproate CoA transferase, ∆dld) synthesized PHA containing 10 mol% of 2HB when cultivated on glucose with addition of sodium (RS)-2HB, and the 2HB composition in PHA increased up to 35 mol% by overexpression phaC. The solvent fractionation and NMR analyses showed that the resulting PHAs were most likely to be block polymers consisting of P(3HB-co-3HV) and P(2HB) segments, suggesting that PhaC functions as the sequence-regulating PHA synthase independently from genetic and metabolic backgrounds of the host cell. KEY POINTS: (R/S)-2-hydroxubutyrates (2HB) caused l-valine deletion in Ralstonia eutropha (R)- and (S)-lactate/2HB dehydrogenases functional in R. eutropha were identified The engineered R. eutropha synthesized block copolymers of 2HB-containing polyhydroxyalkanoates on glucose and 2HB.
Topics: Cupriavidus necator; L-Lactate Dehydrogenase; Lactate Dehydrogenases; Cadmium; Hydroxybutyrates; Polyhydroxyalkanoates; Polyesters; Escherichia coli; Valine; Lactates; Glucose
PubMed: 37773219
DOI: 10.1007/s00253-023-12797-6 -
Heliyon Sep 2023Finding eco-friendly alternatives for antibiotics in treating bacterial diseases affecting the aquaculture sector is essential. Herbal plants are promising alternatives,...
Finding eco-friendly alternatives for antibiotics in treating bacterial diseases affecting the aquaculture sector is essential. Herbal plants are promising alternatives, especially when combined with nanomaterials. Neem () leaves extract was synthesized using a chitosan nanocapsule. Chitosan neem nanocapsule (CNNC) was tested in- and in- against the () challenge in Nile tilapia. A preliminary experiment with 120 Nile tilapia was conducted to determine the therapeutic dose of CNNC, which was established to be 1 mg/L. A treatment study was applied for seven days using 200 fish categorized into four groups (10 fish/replicate: 50 fish/group). The first (control) and second (CNNC) groups were treated with 0 and 1 mg/L CNNC in water without being challenged. The third () and fourth (CNNC + ) groups were treated with 0 and 1 mg/L CNNC, respectively, and challenged with (1 × 10 CFU/mL). Interestingly, CNNC had an in- antibacterial activity against ; the minimum inhibitory concentration and minimum bactericidal concentration of CNNC against were 6.25 and 12.5 mg/mL, respectively. challenge caused behavioral alterations, skin hemorrhage, fin rot, and reduced survivability (60%). The infected fish suffered a noticeable elevation in the malondialdehyde level and hepato-renal function markers (aspartate aminotransferase, alanine aminotransferase, and creatinine). Moreover, a clear depletion in the level of the antioxidant and immune indicators (catalase, reduced glutathione, lysozymes, nitric oxide, and complement 3) was obvious in the group. Treatment of the challenged fish with 1 mg/L CNNC recovered these parameters and enhanced fish survivability. Overall, CNNC can be used as a new versatile tool at 1 mg/L as a water treatment for combating the challenge for sustainable aquaculture production.
PubMed: 37662722
DOI: 10.1016/j.heliyon.2023.e19354 -
Frontiers in Microbiology 2023Infectious hematopoietic necrosis (IHN) is a major disease that limits the culture of rainbow trout. In practical production, it has been found that the temperature of...
Metagenomic and metabolomic analysis of changes in intestinal contents of rainbow trout () infected with infectious hematopoietic necrosis virus at different culture water temperatures.
Infectious hematopoietic necrosis (IHN) is a major disease that limits the culture of rainbow trout. In practical production, it has been found that the temperature of the culture water is a crucial factor affecting its mortality. Currently, little is known about how temperature affects the immune response of rainbow trout gut microbiota and metabolites to IHNV. In this study, our main objective is to analyze the changes in gut microorganisms of rainbow trout (juvenile fish with a consistent genetic background) after 14 days of infection with IHNV (5 × 10 pfu/fish) at 12-13°C (C: injected with saline, A: injected with IHNV) and 16-17°C (D: injected with saline, B: injected with IHNV) using metagenomic and metabolomic analyses, and to screen for probiotics that are effective against IHNV. The results showed that infection with IHNV at 12-13°C caused Eukaryote loss. Compared to Group C, Group A showed a significant increase in harmful pathogens, such as Yersiniaceae, and a significant alteration of 4,087 gut metabolites. Compared to group D, group B showed a significant increase in the abundance of Streptococcaceae and , along with significant changes in 4,259 intestinal metabolites. Compared with their respective groups, the levels of two immune-related metabolites, 1-Octadecanoyl-glycero-3-phosphoethanolamine and L-Glutamate, were significantly upregulated in groups A and B. Compared to group B, Group A showed significantly higher pathogenic bacteria including , , and Yersiniaceae, while group B showed a significant increase in Streptococcaceae and . Additionally, there were 4,018 significantly different metabolites between the two groups. Interestingly, 1-Octadecanoyl-sn-glycero-3-phosphoethanolamine and L-Glutamate were significantly higher in group A than in group B. Some of the different metabolites in C vs. A are correlated with , while in D vs. B they were correlated with , and in A vs. B they were correlated with . This study exposed how rainbow trout gut microbiota and metabolites respond to IHNV at different temperatures, and screens beneficial bacteria with potential resistance to IHN, providing new insights and scientific basis for the prevention and treatment of IHN.
PubMed: 37908544
DOI: 10.3389/fmicb.2023.1275649 -
Fish and Shellfish Immunology Reports Dec 2023As one of the mucosal barriers, fish gills represent the first line of defense against pathogen infection. However, the exact mechanism of gill mucosal immune response...
As one of the mucosal barriers, fish gills represent the first line of defense against pathogen infection. However, the exact mechanism of gill mucosal immune response to bacterial infection still needs further investigation in fish. Here, to investigate pathological changes and molecular mechanisms of the mucosal immune response in the gills of crucian carp () challenged by , the transcriptomics and proteomics were performed by using multi-omics analyses of RNA-seq coupled with iTRAQ techniques. The results demonstrated gill immune response were mostly related to the activation of complement and coagulation cascades, antigen processing and presentation, phagosome, NOD-like receptor (NLR) and nuclear factor κB (NFκB) signaling pathway. Selected 21 immune-related DEGs (ie., and ) were verified for their immune roles in the infection using qRT-PCR assay. Meanwhile, some complement (C3, C7, C9, CFD, DF and FH) and antigen presenting (HSP90, MHC Ⅱ, CALR, CANX and PSME) proteins were significantly participated in the process of defense against infections in gill tissues, and protein-protein interaction (PPI) network displayed the immune signaling pathways and interactions among these DEPs. The correlation analysis indicated that the iTRAQ and qRT-PCR results was significantly correlated (Pearson's correlation coefficient = 0.70, < 0.01). To our knowledge, the transcriptomics and proteomics of gills firstly identified by multi-omics analyses contribute to understanding on the molecular mechanisms of local mucosal immunity in cyprinid species.
PubMed: 36589261
DOI: 10.1016/j.fsirep.2022.100077 -
Plants (Basel, Switzerland) Oct 2023This research comparatively investigates the in vitro antimicrobial activity of extracts from (pink water lily) leaves against pathogenic bacteria. The experimental...
This research comparatively investigates the in vitro antimicrobial activity of extracts from (pink water lily) leaves against pathogenic bacteria. The experimental extracts are aqueous, acetonic, and 95% ethanolic extracts; and the pathogenic bacteria being studied include , , , and , which are commonly found in freshwater fish and brackish aquatic animals. The ethanolic extract achieves the highest bacterial inhibitory effects against and . The minimum inhibitory concentrations of the ethanolic extract against and are 10 mg/mL; and 2.5 mg/mL against and . The ethanolic extract is effective against . The high-performance liquid chromatography results show that, in the phenolic acids group, gallic acid is the most dominant (0.600-3.21% /), followed by sinapic acid (0.37-0.83% /). In the flavonoids group, catechin is the most dominant (0.02-1.08% /), followed by rutin (0.002-0.03% /). Essentially, the ethanolic extract can potentially be used as a natural antibiotic agent to treat bacterial infections in fish and aquatic animals.
PubMed: 37896051
DOI: 10.3390/plants12203588 -
Foods (Basel, Switzerland) Feb 2024Bivalves can concentrate biological and chemical pollutants, causing foodborne outbreaks whose occurrence is increasing, due to climatic and anthropic factors that are...
Bivalves can concentrate biological and chemical pollutants, causing foodborne outbreaks whose occurrence is increasing, due to climatic and anthropic factors that are difficult to reverse, hence the need for improved surveillance. This study aimed to evaluate the hygienic qualities of bivalves sampled along the production and distribution chain in Sicily and collect useful data for consumer safety. Bacteriological and molecular analyses were performed on 254 samples of bivalves for the detection of enteropathogenic , spp., spp., spp., and beta-glucuronidase-positive . A total of 96 out of 254 samples, collected in the production areas, were processed for algal biotoxins and heavy metals detection. Bacterial and algal contaminations were also assessed for 21 samples of water from aquaculture implants. spp., spp., , spp., and were detected in 106/254, 79/254, 12/254, 16/254, and 95/254 molluscs, respectively. A total of 10/96 bivalves tested positive for algal biotoxins, and metals were under the legal limit. , and were detected in 5, 3, and 3 water samples, respectively. , , and spp. were detected in water samples collected with the biotoxin-containing molluscs. Traces of yessotoxins were detected in molluscs from water samples containing the corresponding producing algae. Despite the strict regulation by the European Commission over shellfish supply chain monitoring, our analyses highlighted the need for efficiency improvement.
PubMed: 38397529
DOI: 10.3390/foods13040552 -
Antibiotics (Basel, Switzerland) Oct 2023Beta-lactam resistance can lead to increased mortality, higher healthcare expenses, and limited therapeutic options. The primary mechanism of beta-lactam resistance is...
Beta-lactam resistance can lead to increased mortality, higher healthcare expenses, and limited therapeutic options. The primary mechanism of beta-lactam resistance is the production of extended-spectrum beta-lactamases (ESBL) and AmpC beta-lactamases. The spread of beta-lactamase-producing via the food chain may create a resistance reservoir. The aims of this study were to determine the prevalence of ESBL/AmpC-producing in vegetables, to examine the association between EBSL/AmpC-producing bacteria and types of vegetables, packaging, and markets, and to investigate the genetic features of ESBL-producing isolates. The antibiotic susceptibilities were determined using VITEK. Phenotypic ESBL/AmpC production was confirmed using disk diffusion. ESBL-producing isolates were subjected to Fourier-transform infrared (FT-IR) spectroscopy and to whole genome sequencing using Oxford Nanopore sequencing technology. Of the 301 vegetable samples, 20 (6.6%) were positive for ESBL producers (16 and 4 ), and 63 (20.9%) were positive for AmpC producers (56 complex, 4 /, and 3 spp., , and ). The CTX-M and SHV genes were most common among ESBL-producing isolates. The beta-lactamase genes of the ESBL producers were mainly carried on plasmids. Multilocus sequence typing and FT-IR typing revealed high diversity among the ESBL producers. AmpC producers were significantly more common in leafy greens and ESBL producers were significantly less common in climbing vegetables. The presence of ESBL/AmpC-producing in raw vegetables may contribute to the dissemination of resistance genes in the community.
PubMed: 37887229
DOI: 10.3390/antibiotics12101528