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Proceedings of the National Academy of... Nov 2019An earlier report described a human case of necrotizing fasciitis (NF) caused by mixed infection with 4 strains (NF1-NF4). While the NF2, NF3, and NF4 strains were...
An earlier report described a human case of necrotizing fasciitis (NF) caused by mixed infection with 4 strains (NF1-NF4). While the NF2, NF3, and NF4 strains were clonal and possessed exotoxin A (ExoA), the NF1 strain was determined to be phylogenetically distinct, harboring a unique type 6 secretion system (T6SS) effector (TseC). During NF1 and NF2 mixed infection, only NF1 disseminated, while NF2 was rapidly killed by a contact-dependent mechanism and macrophage phagocytosis, as was demonstrated by using in vitro models. To confirm these findings, we developed 2 NF1 mutants (NF1Δ and NF1Δ); encodes an essential T6SS structural component. NF1 VasK and TseC were proven to be involved in contact-dependent killing of NF2 in vitro, as well as in its elimination at the intramuscular injection site in vivo during mixed infection, with overall reduced mouse mortality. ExoA was shown to have an important role in NF by both NF1- (with ) and NF2 during monomicrobial infection. However, the contribution of ExoA was more important for NF2 than NF1 in the murine peritonitis model. The NF2∆ mutant did not significantly alter animal mortality or NF1 dissemination during mixed infection in the NF model, suggesting that the ExoA activity was significant at the injection site. Immunization of mice to ExoA protected animals from NF2 monomicrobial challenge, but not from polymicrobial infection because of NF2 clearance. This study clarified the roles of T6SS and ExoA in pathogenesis caused by NF strains in both mouse peritonitis and NF models in monomicrobial and polymicrobial infections.
Topics: Aeromonas hydrophila; Animals; Bacterial Toxins; Coinfection; Exotoxins; Fasciitis, Necrotizing; Humans; Metagenome; Mice; Peritonitis; Phagocytosis; Type VI Secretion Systems; Virulence
PubMed: 31712444
DOI: 10.1073/pnas.1914395116 -
Viruses Mar 2021is an opportunistic pathogen that infects fish, amphibians, mammals, and humans. This study isolated a myophage, vB_AhyM_Ahp2 (Ahp2), that lytically infects . We...
is an opportunistic pathogen that infects fish, amphibians, mammals, and humans. This study isolated a myophage, vB_AhyM_Ahp2 (Ahp2), that lytically infects . We observed that 96% of the Ahp2 particles adsorbed to within 18 min. Ahp2 also showed a latent period of 15 min with a burst size of 142 PFU/cell. This phage has a linear double-stranded DNA genome of 47,331 bp with a GC content of 57%. At least 20 Ahp2 proteins were detected by SDS-polyacrylamide gel electrophoresis; among them, a 40-kDa protein was predicted as the major capsid protein. Sequence analysis showed that Ahp2 has a genome organization closely related to a group of phages (13AhydR10RR, 14AhydR10RR, 85AhydR10RR, phage 3, 32 Asp37, 59.1), which infect and . The tail module encompassing ORF27-29 in the Ahp2 genome was present in all phages analyzed in this study and likely determines the host range of the virus. This study found that Ahp2 completely lyses AH300206 in 3.5 h at a MOI of 0.0001 and does not lysogenize its host. Altogether, these findings show that Ahp2 is a lytic phage and could be a candidate for therapeutic phage cocktails.
Topics: Aeromonas hydrophila; Bacteriophages; DNA Viruses; Genome, Viral; Host Specificity
PubMed: 33799428
DOI: 10.3390/v13030477 -
MicrobiologyOpen Nov 2019Aeromonas is recognized as a human pathogen following ingestion of contaminated food and water. One major problem in Aeromonas identification is that certain species are...
Proteomic characterization and discrimination of Aeromonas species recovered from meat and water samples with a spotlight on the antimicrobial resistance of Aeromonas hydrophila.
Aeromonas is recognized as a human pathogen following ingestion of contaminated food and water. One major problem in Aeromonas identification is that certain species are phenotypically very similar. The antimicrobial resistance is another significant challenge worldwide. We therefore aimed to use mass spectrometry technology for identification and discrimination of Aeromonas species and to screen the antimicrobial resistance of Aeromonas hydrophila (A. hydrophila). A total of 150 chicken meat and water samples were cultured, and then, the isolates were identified biochemically by the Vitek 2 Compact system. Proteomic identification was performed by MALDI-TOF MS and confirmed by a microchannel fluidics electrophoresis assay. Principal component analysis (PCA) and single-peak analysis created by MALDI were also used to discriminate the Aeromonas species. The antimicrobial resistance of the A. hydrophila isolates was determined by Vitek 2 AST cards. In total, 43 samples were positive for Aeromonas and comprised 22 A. hydrophila, 12 Aeromonas caviae (A. caviae), and 9 Aeromonas sobria (A. sobria) isolates. Thirty-nine out of 43 (90.69%) Aeromonas isolates were identified by the Vitek 2 Compact system, whereas 100% of the Aeromonas isolates were correctly identified by MALDI-TOF MS with a score value ≥2.00. PCA successfully separated A. hydrophila, A. caviae and A. sobria isolates into two groups. Single-peak analysis revealed four discriminating peaks that separated A. hydrophila from A. caviae and A. sobria isolates. The resistance of A. hydrophila to antibiotics was 95.46% for ampicillin, 50% for cefotaxime, 45.45% for norfloxacin and pefloxacin, 36.36% for ceftazidime and ciprofloxacin, 31.81% for ofloxacin and 27.27% for nalidixic acid and tobramycin. In conclusion, chicken meat and water were tainted with Aeromonas spp., with a high occurrence of A. hydrophila. MALDI-TOF MS is a powerful technique for characterizing aeromonads at the genus and species levels. Future studies should investigate the resistance of A. hydrophila to various antimicrobial agents.
Topics: Aeromonas; Aeromonas caviae; Aeromonas hydrophila; Animals; Anti-Bacterial Agents; Bacterial Proteins; Bacterial Typing Techniques; Chickens; Drug Resistance, Bacterial; Humans; Meat; Microbial Sensitivity Tests; Proteome; Proteomics; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Water Microbiology
PubMed: 30614207
DOI: 10.1002/mbo3.782 -
Frontiers in Cellular and Infection... 2022spp. are recognized as opportunistic pathogens causing diseases. Infections in humans can result mainly in gastrointestinal and wound diseases with or without...
spp. are recognized as opportunistic pathogens causing diseases. Infections in humans can result mainly in gastrointestinal and wound diseases with or without progression to septicemia. Although spp. are not known uropathogens and they rarely cause urinary tract infection, we hypothesize that the presence of these bacteria in the water and the contact during, .., recreational and bathing activity can create the conditions for the colonization of the human body and may result to diseases in various locations, including the urinary tract. Our study presents the occurrence of aeromonad fluoroquinolone-susceptible phenotypes with the presence of plasmid-mediated fluoroquinolone resistance (PMQR) genes in a natural freshwater reservoir occasionally used for recreational activities. Sixty-nine isolates collected during the bathing period were identified by mass spectrometry and screened for the presence of fluoroquinolone-resistant phenotypes and genotypes. Fluoroquinolone susceptibility was determined as minimal inhibitory concentration values. PMQR genes were detected by PCR. Isolates comprising eight species, namely, mainly (50.7% isolates) and (24.6% isolates) and rarely , , , , and , were selected. All isolates were phenotypically susceptible either to ciprofloxacin or levofloxacin. Unexpectedly, at least one to three of the PMQR genes were detected in 42.0% of the fluoroquinolone-susceptible spp. phenotypes. Mainly the (34.8% isolates) and (14.5% isolates) determinants were detected. In conclusion, the freshwater reservoir occasionally used for bathing was tainted with aeromonads, with a high occurrence of opportunistic pathogens such as and . MALDI-TOF MS is a powerful technique for aeromonad identification. Our data reveals the mismatch phenomenon between fluoroquinolone-susceptible aeromonad phenotypes and the presence of plasmid-mediated resistance genes. It suggests that phenotypically susceptible bacteria might be a potential source for the storage and transmission of these genes. The exposure during, .., a recreational activity may create the potential risk for causing infections, both diagnostically and therapeutically difficult, after expressing the resistance genes and quinolone-resistant strain selection.
Topics: Aeromonas; Anti-Bacterial Agents; Drug Resistance, Bacterial; Fluoroquinolones; Fresh Water; Phenotype; Plasmids; Quinolones
PubMed: 35646727
DOI: 10.3389/fcimb.2022.885360 -
Viruses Feb 2022Phage therapy can be an effective alternative to standard antimicrobial chemotherapy for control of infections in aquaculture. -specific phages AhMtk13a and AhMtk13b...
Phage therapy can be an effective alternative to standard antimicrobial chemotherapy for control of infections in aquaculture. -specific phages AhMtk13a and AhMtk13b were studied for basic biological properties and genome characteristics. Phage AhMtk13a (Myovirus, 163,879 bp genome, 41.21% CG content) was selected based on broad lytic spectrum and physiologic parameters indicating its lytic nature. The therapeutic potential of phage AhMtk13a was evaluated in experimental studies in zebrafish challenged with GW3-10 via intraperitoneal injection and passive immersion in aquaria water. In experimental series 1 with single introduction of AhMtk13a phage to aquaria water at phage-bacteria ratio 10:1, cumulative mortality 44% and 62% was registered in fish exposed to phage immediately and in 4 h after bacterial challenge, correspondingly, compared to 78% mortality in the group with no added phage. In experimental series 2 with triple application of AhMtk13a phage at ratio 100:1, the mortality comprised 15% in phage-treated group compared to the 55% in the control group. GW3-10 was not detectable in aquaria water from day 9 but still present in fish at low concentration. AhMtk13a phage was maintained in fish and water throughout the experiment at the higher concentration in infected fish.
Topics: Aeromonas hydrophila; Animals; Aquaculture; Bacteriophages; Fish Diseases; Genome, Viral; Gram-Negative Bacterial Infections; Phage Therapy; Zebrafish
PubMed: 35216005
DOI: 10.3390/v14020412 -
International Journal of Molecular... Nov 2021Four chitinases were cloned and characterized from three strains isolated from a mudflat: sp. SK10, sp. SK15, and sp. SK16. In SK10, three genes, Chi18A, Pro2K, and...
Four chitinases were cloned and characterized from three strains isolated from a mudflat: sp. SK10, sp. SK15, and sp. SK16. In SK10, three genes, Chi18A, Pro2K, and Chi19B, were found as a cluster. Chi18A and Chi19B were chitinases, and Pro2K was a metalloprotease. With combinatorial amplification of the genes and analysis of the hydrolysis patterns of substrates, Chi18A and Chi19B were found to be an endochitinase and exochitinase, respectively. Chi18A and Chi19B belonged to the glycosyl hydrolase family 18 (GH18) and GH19, with 869 and 659 amino acids, respectively. Chi18C from SK15 belonged to GH18 with 864 amino acids, and Chi18D from SK16 belonged to GH18 with 664 amino acids. These four chitinases had signal peptides and high molecular masses with one or two chitin-binding domains and, interestingly, preferred alkaline conditions. In the activity staining, their sizes were determined to be 96, 74, 95, and 73 kDa, respectively, corresponding to their expected sizes. Purified Chi18C and Chi18D after pET expression produced ,'-diacetylchitobiose as the main product in hydrolyzing chitooligosaccharides and colloidal chitin. These results suggest that Chi18A, Chi18C, and Chi18D are endochitinases, that Chi19B is an exochitinase, and that these chitinases can be effectively used for hydrolyzing natural chitinous sources.
Topics: Aeromonas; Bacterial Proteins; Betaproteobacteria; Chitin; Chitinases; Geologic Sediments; Hydrolysis; Phylogeny
PubMed: 34884628
DOI: 10.3390/ijms222312822 -
Environmental Microbiology Reports Aug 2019Aeromonas hydrophila and Aeromonas caviae adapt to saline water environments and are the most predominant Aeromonas species isolated from estuaries. Here, we isolated...
Potential KPC-2 carbapenemase reservoir of environmental Aeromonas hydrophila and Aeromonas caviae isolates from the effluent of an urban wastewater treatment plant in Japan.
Aeromonas hydrophila and Aeromonas caviae adapt to saline water environments and are the most predominant Aeromonas species isolated from estuaries. Here, we isolated antimicrobial-resistant (AMR) Aeromonas strains (A. hydrophila GSH8-2 and A. caviae GSH8M-1) carrying the carabapenemase bla gene from a wastewater treatment plant (WWTP) effluent in Tokyo Bay (Japan) and determined their complete genome sequences. GSH8-2 and GSH8M-1 were classified as newly assigned sequence types ST558 and ST13, suggesting no supportive evidence of clonal dissemination. The strains appear to have acquired bla -positive IncP-6-relative plasmids (pGSH8-2 and pGSH8M-1-2) that share a common backbone with plasmids in Aeromonas sp. ASNIH3 isolated from hospital wastewater in the United States, A. hydrophila WCHAH045096 isolated from sewage in China, other clinical isolates (Klebsiella, Enterobacter and Escherichia coli), and wastewater isolates (Citrobacter, Pseudomonas and other Aeromonas spp.). In addition to bla , pGSH8M-1-2 carries an IS26-mediated composite transposon including a macrolide resistance gene, mph(A). Although Aeromonas species are opportunistic pathogens, they could serve as potential environmental reservoir bacteria for carbapenemase and AMR genes. AMR monitoring from WWTP effluents will contribute to the detection of ongoing AMR dissemination in the environment and might provide an early warning of potential dissemination in clinical settings and communities.
Topics: Aeromonas; Aeromonas caviae; Aeromonas hydrophila; Anti-Bacterial Agents; Bacterial Proteins; Cities; DNA Transposable Elements; Drug Resistance, Bacterial; Genome, Bacterial; Japan; Microbial Sensitivity Tests; Plasmids; Wastewater; Water Microbiology; beta-Lactamases
PubMed: 31106978
DOI: 10.1111/1758-2229.12772 -
Microbiology Spectrum Jun 2022KPC-24, different from KPC-2 by a single amino acid alteration at codon 6 (R6P), was initially discovered in Klebsiella pneumoniae in Chile. Here, we reported...
KPC-24, different from KPC-2 by a single amino acid alteration at codon 6 (R6P), was initially discovered in Klebsiella pneumoniae in Chile. Here, we reported KPC-24-producing Aeromonas veronii isolates from hospital sewage in China. The was cloned and the MICs were tested against β-lactams antimicrobial agents. KPC-24 exhibited a β-lactam susceptibility profile similar to that of KPC-2. Whole-genome sequencing and analysis revealed that was located within a Tn-related region on an IncP-6 plasmid. Our study described a variant of K. pneumoniae carbapenemase (KPC), KPC-24, from two A. veronii strains isolated from hospital sewage, in which antibiotics, biocides, pharmaceuticals, and heavy metals may supply an appropriate condition for the evolution of carbapenemases. Some variants exhibited stronger hydrolysis activity to antibiotics and gave rise to a major public health concern. More seriously, species are prevalent in aquatic environments and, thus, may act as a suitable vector for antibiotics-resistance genes and foster the transmission of resistance. We should attach importance to surveying the evolution and transmission of antibiotics-resistance genes.
Topics: Aeromonas veronii; Anti-Bacterial Agents; Bacterial Proteins; Hospitals; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Plasmids; Sewage; beta-Lactamases
PubMed: 35546572
DOI: 10.1128/spectrum.00555-22 -
Molecular Biology and Evolution May 2021Horizontal gene transfer (HGT) is central to prokaryotic evolution. However, little is known about the "scale" of individual HGT events. In this work, we introduce the...
Horizontal gene transfer (HGT) is central to prokaryotic evolution. However, little is known about the "scale" of individual HGT events. In this work, we introduce the first computational framework to help answer the following fundamental question: How often does more than one gene get horizontally transferred in a single HGT event? Our method, called HoMer, uses phylogenetic reconciliation to infer single-gene HGT events across a given set of species/strains, employs several techniques to account for inference error and uncertainty, combines that information with gene order information from extant genomes, and uses statistical analysis to identify candidate horizontal multigene transfers (HMGTs) in both extant and ancestral species/strains. HoMer is highly scalable and can be easily used to infer HMGTs across hundreds of genomes. We apply HoMer to a genome-scale data set of over 22,000 gene families from 103 Aeromonas genomes and identify a large number of plausible HMGTs of various scales at both small and large phylogenetic distances. Analysis of these HMGTs reveals interesting relationships between gene function, phylogenetic distance, and frequency of multigene transfer. Among other insights, we find that 1) the observed relative frequency of HMGT increases as divergence between genomes increases, 2) HMGTs often have conserved gene functions, and 3) rare genes are frequently acquired through HMGT. We also analyze in detail HMGTs involving the zonula occludens toxin and type III secretion systems. By enabling the systematic inference of HMGTs on a large scale, HoMer will facilitate a more accurate and more complete understanding of HGT and microbial evolution.
Topics: Aeromonas; Gene Transfer, Horizontal; Genomics; Software
PubMed: 33565580
DOI: 10.1093/molbev/msab043 -
The Brazilian Journal of Infectious... 2019Aeromonas species are renowned enteric pathogens with virulence determinants linked to human diseases, such as gastroenteritis, skin, soft-tissue and muscle infections,...
INTRODUCTION
Aeromonas species are renowned enteric pathogens with virulence determinants linked to human diseases, such as gastroenteritis, skin, soft-tissue and muscle infections, and septicemia. A recent concern of resistance in this organism has emerged, especially the presence carbapenemases. Herein we describe a case series of emerging carbapenem-resistant Aeromonas species infection in our hospital in Cali, Colombia.
MATERIALS AND METHODS
Cases from 2012 to 2018 are reported. Clinical data was abstracted from the clinical charts and laboratory information. Phenotypic detection of resistance was identified using the VITEK®2 system (BioMérieux) and broth microdilution MicroScan WalkAway plus System (Beckman Coulter). CARBA NP-test and multiplex qPCR assay was performed in 11 isolates to identify genes encoding carbapenemases (bla bla bla and bla).
RESULTS
21 cases of Aeromonas infection in hospitalized patients with phenotypic resistance to carbapenems were studied. The median age was 50 years, 55% (12/21) were male, and 67% (14/21) were healthcare-associated infections (HAI). Aeromonas hydrophila was the most common species (19/21). Forty-three percent (9/21) of the patients were immunocompromised. The mortality was 33% (7/21), and in patients with bacteremia was 100%. Most patients received empirical treatment with meropenem and failed to this treatment. PCR amplification tests showed negative results for the carbapenemases analyzed.
CONCLUSION
Emerging phenotypic carbapenem-resistant infection has been seen in our hospital, most as HAI. High mortality was found, especially in immunocompromised patients and in those who failled empirical treatment with carbapenems. As the main carbapenemases tested were negative, carbapenem-resistant could be attributed to an intrinsic metallo-β-lactamase, CphA encoded by the cphA gene, possible hyperproduction of ampC β-lactamase and/or porins expression.
Topics: Adult; Aeromonas; Aged; Anti-Bacterial Agents; Carbapenems; Colombia; Cross-Sectional Studies; Female; Gram-Negative Bacterial Infections; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Phenotype; beta-Lactam Resistance; beta-Lactamases
PubMed: 31541615
DOI: 10.1016/j.bjid.2019.08.005