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Antibiotics (Basel, Switzerland) Mar 2022The emergence of antimicrobial-resistant bacteria is an enormous challenge to public health. and are opportunistic pathogens in fish. They exert tremendous adverse...
The emergence of antimicrobial-resistant bacteria is an enormous challenge to public health. and are opportunistic pathogens in fish. They exert tremendous adverse effects on aquaculture production, owing to their acquired antibiotic resistance. A few Clinical and Laboratory Standards Institute (CLSI) epidemiological cut-off values (ECVs) against spp. are available. We evaluated antimicrobial susceptibility by establishing 8 ECVs using two analytical methods, normalized resistance interpretation and ECOFFinder. We detected antimicrobial resistance genes in two motile spp. isolated from aquatic animals. Results showed that 89.2% of and 75.8% of isolates were non-wild types according to the oxytetracycline ECV and ECV, respectively. The antimicrobial resistance genes included , , , , , , , , , , and . The most common gene in spp. isolates was , followed by . Some strains carried more than one gene, with - and - found in ; however, was not detected in any of the strains. Furthermore, 18.6% of and 24.2% of isolates showed presumptive multidrug-resistant phenotypes. The emergence of multidrug resistance among aquatic aeromonads suggests the spread of drug resistance and difficult to treat bacterial infections.
PubMed: 35326806
DOI: 10.3390/antibiotics11030343 -
Frontiers in Microbiology 2021) is a zoonotic pathogen. It causes clinically a variety of diseases such as dysentery, bacteremia, and meningitis, and brings huge losses to aquaculture. has been...
) is a zoonotic pathogen. It causes clinically a variety of diseases such as dysentery, bacteremia, and meningitis, and brings huge losses to aquaculture. has been documented as a multiple antibiotic resistant bacterium. Hfq (host factor for RNA bacteriophage Qβ replication) participates in the regulations of the virulence, adhesion, and nitrogen fixation, effecting on the growth, metabolism synthesis and stress resistance in bacteria. The deletion of gene in showed more sensitivity to trimethoprim, accompanying by the upregulations of purine metabolic genes and downregulations of efflux pump genes by transcriptomic data analysis. Coherently, the complementation of efflux pump-related genes and recovered the trimethoprim resistance in Δ. Besides, the accumulations of adenosine and guanosine were increased in Δ in metabonomic data. The strain Δ conferred more sensitive to trimethoprim after appending 1 mM guanosine to M9 medium, while wild type was not altered. These results demonstrated that Hfq mediated trimethoprim resistance by elevating efflux pump expression and degrading adenosine, and guanosine metabolites. Collectively, Hfq is a potential target to tackle trimethoprim resistance in infection.
PubMed: 34899630
DOI: 10.3389/fmicb.2021.742114 -
Applied and Environmental Microbiology Mar 2021is included in the Dutch Drinking Water Decree as an indicator for elevated microbial regrowth in non-chlorinated drinking water distribution systems (DWDS). The...
is included in the Dutch Drinking Water Decree as an indicator for elevated microbial regrowth in non-chlorinated drinking water distribution systems (DWDS). The temporal and spatial diversity of species in ten DWDS and their planktonic growth characteristics for different carbon sources was investigated. Genotyping of the B gene of isolates showed a non-systematic temporal and spatial variable prevalence of seven different species in these DWDS and no correlation with AOC-P17/NOX and concentrations. Pure cultures of these seven species showed a high affinity to low concentrations (μg/L) of individual amino acids and fatty acids, compounds associated with biomass. Growth occurred at 0.5 μg-C/L of an amino acid mixture. Growth of a mixed community of , , and in drinking water occurred in pasteurized samples, however, no growth and decay occurred in competition with the autochthonous bacteria (non-pasteurized samples). This community also failed to grow in non-pasteurized distribution samples from a location with clear increase in planktonic concentrations in the transported drinking water. For competitive planktonic growth of an amino acid concentration of ≥5 μg-C/L is required. AOC-P17/NOX concentrations showed that such concentrations are not expected in Dutch drinking water. Therefore, we suspect that competitive planktonic growth is not the major cause of the observed non-compliance with the standard in non-chlorinated DWSD. The occurrence of the bacterial genus in non-chlorinated drinking water in the Netherlands is regarded as an indication for elevated microbial regrowth in the distribution system. Identification of the prevalent species in ten distribution systems by genotyping yielded seven different species, with , and as the most dominant ones. Planktonic growth experiments of pure cultures confirmed former published affinity of for certain biomass compounds (amino and fatty acids). In competition with the autochthonous microflora, however, planktonic growth was not observed, only after addition of a threshold amino acid concentration of 5 μg-C/L. Based on our results and further observations we deduced that planktonic growth of in the DWDS is not very likely. Benthic growth in loose deposits and planktonic release is a more plausible explanation for the observed planktonic increase of .
PubMed: 33310721
DOI: 10.1128/AEM.02867-20 -
Pathogens (Basel, Switzerland) Oct 2022is associated with substantial economic losses in the fish industry and with food-borne illness in humans. This study aimed to determine the prevalence, antibiogram...
is associated with substantial economic losses in the fish industry and with food-borne illness in humans. This study aimed to determine the prevalence, antibiogram profiles, sequence analysis, virulence and antimicrobial resistance genes, and pathogenicity of recovered from . A total of 80 fish were randomly gathered from various private farms in Suez Province, Egypt. Subsequently, samples were subjected to clinical, post-mortem, and bacteriological examinations. The retrieved isolates were tested for sequence analysis, antibiogram profile, pathogenicity, and PCR detection of virulence and resistance genes. The prevalence of in the examined was 22.5 % (18/80). The phylogenetic analyses revealed that the tested strains shared high genetic similarity with other strains from India, UK, and China. Using PCR it was revealed that the retrieved isolates harbored the A, , , AII, , , and virulence genes with prevalence of 100%, 82.9%, 61.7%, 55.3%, 44.7%, 36.17%, and 29.8%, respectively. Our findings revealed that 29.8% (14/47) of the retrieved strains were XDR to nine antimicrobial classes and carried , , A, A1, and 1 resistance genes. Likewise, 19.1% (9/47) of the obtained strains were MDR to eight classes and possessed , , A, A1, and 1 genes. The pathogenicity testing indicated that the mortality rates positively correlated with the prevalence of virulence-determinant genes. To our knowledge, this is the first report to reveal the occurrence of XDR and MDR in , an emergence that represents a risk to public health. Emerging XDR and MDR in frequently harbored A, , , AII, and virulence genes, and , 1, A, , , and A1 resistance genes.
PubMed: 36365013
DOI: 10.3390/pathogens11111262 -
Pathogens (Basel, Switzerland) Apr 2023A case of severe mortality in farmed was investigated to characterize the causative agent. We identified the bacterial strain as isolated from the gut of infected by...
A case of severe mortality in farmed was investigated to characterize the causative agent. We identified the bacterial strain as isolated from the gut of infected by biochemical assay, scanning electron microscopy and 16S rRNA gene sequence analysis. The in vivo challenge experiment showed that the LD of was 2.2 × 10 CFU/fish. Virulence gene investigation revealed that the isolated possesses Aerolysin, Cytotoxic enterotoxin, Serine protease, Dnase and Type III secretion system genes. The isolated strain was resistant to two antibiotics (ampicillin and dicloxacillin) while susceptible to 22 other antibiotics. The study further revealed that induced both stresses along with non-specific and specific immune responses marked by elevated cortisol HSP70, HSP90 and IgM levels in the treated fingerlings. Although the bacterial pathogen enhances the immune response, the negative effect on fish, including stress, and high mortality, create concern and a need for management in farms. The knowledge gained from this study would facilitate future research aimed at assessing the pathogenicity of , with an emphasis on microbial disease management in other farmed fish species.
PubMed: 37111485
DOI: 10.3390/pathogens12040598 -
Antimicrobial Resistance and Infection... Feb 2021The study aimed to elucidate the species taxonomy, clinical manifestations, virulence gene profiles and antimicrobial susceptibilities of Aeromonas strains isolated from...
BACKGROUND
The study aimed to elucidate the species taxonomy, clinical manifestations, virulence gene profiles and antimicrobial susceptibilities of Aeromonas strains isolated from life-threatening bacteremia in southeastern China.
METHODS
Clinical samples of Aeromonas causing bacteremia were isolated from a teaching hospital in Wenzhou from 2013 to 2018 and a retrospective cohort study was performed. Aeromonas strains were identified at species level by housekeeping gene gyrB. Virulence and drug resistance-associated genes were screened by polymerase chain reaction (PCR) and antimicrobial susceptibility testing (AST) was performed by the VITEK 2 Compact system.
RESULTS
A total of 58 Aeromonas isolated from patients with bacteremia were collected during 6 years (2013-2018). 58 isolates were identified to five different species, where Aeromonas dhakensis appeared to be the predominant species (26/58), followed by Aeromonas veronii (13/58), Aeromonas caviae (10/58), Aeromonas hydrophila (7/58) and Aeromonas jandaei (2/58). 16 of 58 patients had poor prognosis. Poor prognosis was significantly associated with liver cirrhosis and inappropriate empirical antimicrobials therapy. The progression of bacteremia caused by Aeromonas was extremely fast, especially in A. dhakensis infections. Virulence genes aer, lip, hlyA, alt, ast, and act, were detected at ratios of 24.1% (14/58), 62.1% (36/58), 65.5% (38/58), 58.6% (34/58), 15.5% (9/58) and 65.5% (38/58), respectively. Antimicrobial susceptibility testing exhibited that 9 out of 58 isolates were identified as multi-drug resistant (MDR) organism. The bla gene was identified in all 9 MDR isolates. bla, bla, bla, bla, bla and aac(6')-Ib-cr were detected in 4 isolates, 2 isolates, 1 isolate, 3 isolates, 8 isolates, and 3 isolates, respectively. The majority of Aeromonas strains maintained susceptible to 3rd generation cephalosporins, aminoglycosides, fluoroquinolones and furantoin.
CONCLUSIONS
The prevalence and dangerousness of Aeromonas infections, especially A. dhakensis, are underestimated in clinic. Continuous monitoring is essential to keep track of MDR Aeromonas due to the increasing prevalence recently and a more effective measure is required to control the spread of resistance determinants.
Topics: Adult; Aeromonas; Aged; Anti-Bacterial Agents; Bacteremia; China; Female; Gram-Negative Bacterial Infections; Hospitals, Teaching; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Phylogeny; Retrospective Studies; Virulence; Virulence Factors
PubMed: 33640019
DOI: 10.1186/s13756-021-00911-0 -
Antibiotics (Basel, Switzerland) Feb 2024spp. are environmental bacteria able to infect animals and humans. Here, we aim to evaluate the role of biofilms in persistence in freshwater. were isolated from...
spp. are environmental bacteria able to infect animals and humans. Here, we aim to evaluate the role of biofilms in persistence in freshwater. were isolated from water and biofilm samples and identified by Vitek-MS and sequencing. Antibiotic susceptibility profiles were determined according to EUCAST, and a crystal violet assay was used to assess biofilm assembly. MTT and the enumeration of colony-forming units were used to evaluate biofilm and planktonic susceptibility to chlorination, respectively. Identification at the species level was challenging, suggesting the need to improve the used methodologies. Five different species (, , , and ) were identified from water, and one species was identified from biofilms (). and presented resistance to different antibiotics, whith the highest resistance rate observed for (multiple antibiotic resistance index of 0.25). Of the 21 isolates, 11 were biofilm producers, and 10 of them were strong biofilm producers (SBPs). The SBPs presented increased tolerance to chlorine disinfection when compared with their planktonic counterparts. In order to elucidate the mechanisms underlying biofilm tolerance to chlorine and support the importance of preventing biofilm assembly in water reservoirs, further research is required.
PubMed: 38391552
DOI: 10.3390/antibiotics13020166 -
Animals : An Open Access Journal From... Apr 2020is an important pathogen causing freshwater fish sepsis and ulcer syndrome. An increasing number of cases have demonstrated its significance as an aquatic zoonotic...
is an important pathogen causing freshwater fish sepsis and ulcer syndrome. An increasing number of cases have demonstrated its significance as an aquatic zoonotic agent. The purpose of this study was to ensure the safety of freshwater products by evaluating the infection status of edible freshwater fish. In this experiment, we isolated from several species of apparently healthy freshwater fish, including , , , and . was identified through bacterial staining, culture characteristics, and 16S rDNA gene sequence. In addition, polymerase chain reaction (PCR) was used to investigate the distribution of seven major virulence genes, including aerolysin (: 88.51%), cytotoxic enterotoxin (: 71.26%), serine proteinase (: 54.02%), adhesin (: 40.23%), phospholipase (: 45.98%), nuclease (: 51.72%), and quorum sensing-controlled virulence factor (: 59.77%). In total, 496 strains of were isolated, including 87 strains of . The isolates of were Gram-negative, rod-shaped bacteria, and the colonies are yellow on Rimler-Shotts (RS) medium and showed greater than 99% homology with ATCC35624 according to analyses of the 16S rDNA sequence. Nearly 50% of the isolates carried at least four or more virulence genes, 25% of the isolates carried at least five types of virulence genes, and 59.77% isolates carried the gene, and the isolates carrying more virulence genes were found to be more virulent. These results are of great significance for further improving the food safety assessment of freshwater aquatic products.
PubMed: 32252334
DOI: 10.3390/ani10040608 -
Antibiotics (Basel, Switzerland) Aug 2022A patient with oral squamous cell carcinoma (OSCC) underwent complex surgical tumor therapy, including the reconstruction of soft tissues using a radial forearm flap....
A patient with oral squamous cell carcinoma (OSCC) underwent complex surgical tumor therapy, including the reconstruction of soft tissues using a radial forearm flap. Due to venous congestion that could only partly be resolved by revision surgery, leech therapy was started on the second postoperative day. The patient developed pneumonia and sepsis and died as a result of septic shock, despite having received targeted broad-spectrum antibiotic therapy since day 5. spp. were cultured from both the patient's specimens and unused leeches. Biochemical identification and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) yielded inconsistent identification results. Finally, microbiological identification of spp. was performed via 16S rDNA sequencing and use of the basic local alignment search tool (BLAST), and strains from both the patient and the leeches were identified as . spp. strains derived from the patient and leeches and independent laboratory strains were submitted to randomly amplified polymorphic DNA (RAPD) subtyping. RAPD of strains from both sources revealed an identical pattern, strongly suggesting the transmission of from the leeches to the patient. Physicians should be aware of the potential for severe lethal infections as a fatal side-effect of leech therapy in critically ill patients, which should be addressed using antibiotic prophylaxis.
PubMed: 36139958
DOI: 10.3390/antibiotics11091180 -
Frontiers in Microbiology 2022The aquatic environment is an important medium for the accumulation and dissemination of antibiotic-resistant bacteria as it is often closely related to human...
The aquatic environment is an important medium for the accumulation and dissemination of antibiotic-resistant bacteria as it is often closely related to human activities. Previous studies paid little attention to the prevalence and mechanism of polymyxin-resistant bacteria in the aquatic environment. As a Gram-negative opportunistic pathogen widely distributed in aquatic ecosystems, the antibiotic-resistant profile of spp. deserves much attention. In this study, we identified 61 spp. isolates from water samples in the section of the Yangtze River. The total polymyxin B (PMB) resistance rate of these strains was 49.18% (30/61), showing a high level of polymyxin resistance in spp. The MIC and MIC for PMB exhibited a significant discrepancy among different species ( < 0.001). The MIC and MIC for PMB in the were 128 mg/L and above 128 mg/L while in and , the MIC and MIC value were both 2 mg/L. Only two . strains (MIC = 2 mg/L) and one . strain (MIC = 0.5 mg/L) were identified as carrying mobilized polymyxin resistant gene ., and .. All genes were located in the chromosome. This is the first report that the downstream region of -3.42 was the truncated -like gene separated by the insertion sequences of IS (1,674 bp) and IS (1,084 bp). Analysis of epidemiology of -positive genomes from GenBank database showed that the genus and the aquatic environment might be the potential container and reservoir of . By the whole-genome sequencing and qRT-PCR, we inferred that the sequence differences in the AAA domain of MlaF protein and its expression level among these three species might be involved in the development of polymyxin resistance. Our study provided evidences of the possible mechanism for the variety of polymyxin susceptibility in different species of the genus and a theoretical basis for the surveillance of the aquatic environment.
PubMed: 36386612
DOI: 10.3389/fmicb.2022.1030564