Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 576
Filtrar
1.
Lett Appl Microbiol ; 70(3): 221-229, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31854000

RESUMO

Hard-shelled mussel (Mytilus coruscus) is a popular seafood in Korea. This study aimed to determine the virulence markers and antimicrobial resistance patterns of 33 Aeromonas strains isolated from mussels. The isolates were identified as A. salmonicida (n = 14), A. veronii (n = 9), A. enteropelogenes (n = 4), A. caviae (n = 3), A. allosaccharophila (n = 2) and A. bivalvium (n = 1) by gyrB gene sequencing. The sequence divergence between and within the species ranged from 3·70 to 10·40% and 0-1·50% respectively. Every species formed a distinct group in a neighbour-joining phylogenetic tree. The DNase, gelatinase, caseinase, ß-haemolysis, biofilm and lipase activities were observed in 33 (100·00%), 31 (93·93%), 30 (90·90%), 27 (81·81%), 21 (63·63%) and 17 (51·51%) isolates respectively. The virulence genes were detected by PCR in the following frequencies: fla (90·09%), aer (87·88%), hlyA (87·88%), ahyB (81·19%), gcaT (75·76%), ser (69·70%), lip (66·67%), alt (57·58%), ast (51·51%) and act (21·21%). Every isolate was resistant to at least three of 18 antimicrobials in the disk diffusion test. The multiple antimicrobial resistance index values ranged from 0·11 to 0·44 among the isolates. Our study suggests that mussels can be a potential reservoir of virulent and multidrug-resistant Aeromonas sp. SIGNIFICANCE AND IMPACT OF THE STUDY: Aeromonas sp. are known as common pathogenic bacteria isolated from seafood. The virulence factors and antimicrobial resistance profiles of mussel-borne Aeromonas sp. are poorly understood. This study demonstrated for the first time the existence of virulence markers and antimicrobial resistance of Aeromonas sp. from mussels in Korea. Majority of the isolates were positive for phenotypic virulence characteristics and harboured several virulence genes which reveal the potential virulence of mussel-borne Aeromonas sp. Multiple antimicrobial resistance was also observed among the isolates. Our study highlights the importance of food safety standards in mussel consumption.


Assuntos
Aeromonas/classificação , Aeromonas/isolamento & purificação , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Mytilus/microbiologia , Aciltransferases/genética , Aeromonas/genética , Aeromonas/patogenicidade , Animais , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Infecções por Bactérias Gram-Negativas/microbiologia , Lipase/genética , Filogenia , Reação em Cadeia da Polimerase , República da Coreia , Alimentos Marinhos/microbiologia , Virulência/genética , Fatores de Virulência/genética
2.
Arq. bras. med. vet. zootec. (Online) ; 71(5): 1609-1615, set.-out. 2019. tab
Artigo em Português | LILACS, VETINDEX | ID: biblio-1038678

RESUMO

Objetivou-se avaliar a ocorrência de Aeromonas spp. em peixes e amostras de água na região semiárida de Pernambuco e avaliar a frequência de aerolissina (aerA), enterotoxina citotóxica (act), enterotoxina citotônica (alt) e serina protease (ahp) nesses isolados. Foram analisados 70 peixes vivos e oito mortos com sinais clínicos de aeromoniose e 16 amostras de água. Aeromonas spp. foram identificadas por análises microbiológicas (provas bioquímicas) e molecular, usando-se primers específicos para a região 16S rRNA, e a distribuição dos quatro fatores de virulência (aerA, alt, act e ahp) foi investigada por ensaio de PCR. Cento e cinquenta e cinco (84,7%) isolados foram confirmados como Aeromonas spp. na análise molecular. Os genes de virulência mais frequentes foram act (53,55%) e aerA (51,61%). De acordo com o tipo de amostra, observou-se maior frequência do gene aerA (87,5% P=0,0474) em isolados de peixes mortos e a menor frequência do gene act (47,73% P=0,0002) em peixes vivos. Este estudo demonstrou a presença de aeromoniose no cultivo de tilápias em tanques-rede, nos municípios de Jatobá e Petrolândia, na região semiárida de Pernambuco. A detecção de aerA, act e alt pode ser utilizada na tipagem de virulência de Aeromonas spp.(AU)


The purpose of this study was to evaluate the occurrence of Aeromonas spp. from fishes and tilapia net-cage farm water in semi-arid regions of Pernambuco and to evaluate the frequency of the aerolysin (aerA), cytotoxic enterotoxin (act), cytotonic enterotoxin (alt) and serine protease (ahp) genes in Aeromonas isolates. 70 live and eight dead fish with aeromoniosis clinical signs and 16 water samples were analyzed. Aeromonas spp. isolated were identified by microbiological (biochemical evidence) and molecular analysis using specific primers for 16SrRNA region, while the distribution of four virulence factors, including aerA, alt, act and ahp, was investigated by PCR assay. One hundred fifty-five (84.7%) isolates were confirmed as Aeromonas spp. by molecular analysis. The most frequent virulence genes in isolates were act (53.55%) and aerA (51,61%). According to the kind of sample, the higher frequency of aerA gene (87.5% P= 0.0474) was observed in isolates from dead fish and the lowest frequency of act gene (47.73% P= 0.0002) from live fish. This study found the presence of aeromoniosis on tilapia farming in net-cages on Jatobá and Petrolândia counties in the semiarid Pernambuco region. The detection of aerA, act and alt can be used for virulence typing of Aeromonas spp. isolates.(AU)


Assuntos
Animais , Tilápia/microbiologia , Aeromonas/patogenicidade , Ciclídeos/microbiologia , Pesqueiros , Virulência
3.
PLoS One ; 14(8): e0221344, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31419250

RESUMO

Aeromonas sobria is a pathogen causing food-borne illness. In immunocompromised patients and the elderly, A. sobria can leave the intestinal tract, and this opportunistically leads to severe extraintestinal diseases including sepsis, peritonitis, and meningitis. To cause such extraintestinal diseases, A. sobria must pass through the intestinal epithelial barrier. The mechanism of such bacterial translocation has not been established. Herein we used intestinal (T84) cultured cells to investigate the effect of A. sobria serine protease (ASP) on junctional complexes that maintain the intercellular adhesion of the intestinal epithelium. When several A. sobria strains were inoculated into T84 monolayer grown on Transwell inserts, the strain with higher ASP production largely decreased the value of transepithelial electrical resistance exhibited by the T84 monolayer and markedly caused bacterial translocation from the apical surface into the basolateral side of T84 monolayer. Further experiments revealed that ASP acts on adherens junctions (AJs) and causes the destruction of both nectin-2 and afadin, which are protein components constituting AJs. Other studies have not revealed the bacterial pathogenic factors that cause the destruction of both nectin-2 and afadin, and our present results thus provide the first report that the bacterial extracellular protease ASP affects these molecules. We speculate that the destruction of nectin-2 and afadin by the action of ASP increases the ability of A. sobria to pass through intestinal epithelial tissue and contributes to the severity of pathological conditions.


Assuntos
Aeromonas/patogenicidade , Proteínas de Bactérias/metabolismo , Doenças Transmitidas por Alimentos/patologia , Mucosa Intestinal/patologia , Serina Proteases/metabolismo , Aeromonas/metabolismo , Translocação Bacteriana , Técnicas de Cultura de Células , Linhagem Celular , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Mucosa Intestinal/citologia , Cinesina/metabolismo , Miosinas/metabolismo , Nectinas/metabolismo
4.
PLoS One ; 14(6): e0214035, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31163020

RESUMO

The genetic determinants of bacterial pathogenicity are highly variable between species and strains. However, a factor that is commonly associated with virulent Gram-negative bacteria, including many Aeromonas spp., is the type 3 secretion system (T3SS), which is used to inject effector proteins into target eukaryotic cells. In this study, we developed a bioinformatics pipeline to identify T3SS effector proteins, applied this approach to the genomes of 105 Aeromonas strains isolated from environmental, mutualistic, or pathogenic contexts and evaluated the cytotoxicity of the identified effectors through their heterologous expression in yeast. The developed pipeline uses a two-step approach, where candidate Aeromonas gene families are initially selected using Hidden Markov Model (HMM) profile searches against the Virulence Factors DataBase (VFDB), followed by strict comparisons against positive and negative control datasets, greatly reducing the number of false positives. This approach identified 21 Aeromonas T3SS likely effector families, of which 8 represent known or characterized effectors, while the remaining 13 have not previously been described in Aeromonas. We experimentally validated our in silico findings by assessing the cytotoxicity of representative effectors in Saccharomyces cerevisiae BY4741, with 15 out of 21 assayed proteins eliciting a cytotoxic effect in yeast. The results of this study demonstrate the utility of our approach, combining a novel in silico search method with in vivo experimental validation, and will be useful in future research aimed at identifying and authenticating bacterial effector proteins from other genera.


Assuntos
Aeromonas/patogenicidade , Sistemas de Secreção Tipo III/metabolismo , Fatores de Virulência/toxicidade , Aeromonas/genética , Aeromonas/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/toxicidade , Biologia Computacional/métodos , Simulação por Computador , Genoma Bacteriano , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/efeitos dos fármacos , Fatores de Virulência/genética
5.
J Appl Microbiol ; 127(2): 418-428, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31136041

RESUMO

AIMS: Under intensive and stressful aquaculture conditions, cultured eels are highly susceptible to virulent Aeromonas sp. infections. To rapidly and simultaneously confirm Aeromonas isolate and its virulence, a two-tube multiplex PCR (mPCR) assay incorporating gyrB gene for genus-specific recognition and seven major virulence genes for virulence assessment was developed. METHODS AND RESULTS: Eight pairs of primers were designed and divided into two groups-gyrB, ahpA, epr and aerA in tube 1 and alt, act, ast and hlyA in tube 2. The optimized mPCR conditions were the same except for their final concentrations. The specificity of the mPCR was validated by the extracted DNA of 10 Aeromonas and 8 non-Aeromonas species, or mixed DNA templates. Detection limits were determined to be 200 copies per µl in tube 1 and 20 copies per µl in tube 2. The mPCR reproducibility was tested by both artificial challenge and clinical samples. CONCLUSIONS: The results showed this two-tube mPCR assay was rapid, specific, sensitive and reliable. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report to distinguish virulent Aeromonas isolates from nonvirulent ones by seven popular and major virulence genes at the genus-specific level. And it will be useful for large-scale screening of virulent Aeromonas sp. in cultured eels.


Assuntos
Aeromonas/isolamento & purificação , Aeromonas/patogenicidade , Enguias/microbiologia , Reação em Cadeia da Polimerase Multiplex/métodos , Aeromonas/genética , Animais , Aquicultura , Primers do DNA , Reprodutibilidade dos Testes , Fatores de Virulência/genética
6.
Lett Appl Microbiol ; 69(2): 100-109, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31107978

RESUMO

Members of the genus Aeromonas are opportunistic pathogen of a variety of aquatic animals that exhibits multidrug resistance, phenotypes, virulence genes and virulence. The present study described the species distribution and the potential pathogenicity of Aeromonas isolated from healthy Northern snakehead (Channa argus) in China. Molecular identification revealed that A. veronii biovar veronii (69/167; 41·3%) and A. hydrophila (41/167; 24·6%) were the most common species found in Northern snakehead intestine based on sequencing of the 16S rRNA gene and DNA gyrase subunit B protein. The distribution of seven virulence factors including aer (84·4%), act (80·8%), ser (40·1%), Aha (27·5%), lip (23·4%), exu (15·0%) and LuxS (12·6%) were determined exclusively in Aeromonas isolates. All the seven virulence genes were present in 9·6% (16/167), among which 11 strains were identified as A. veronii biovar veronii. For the strains harbouring seven virulence genes, the 50% lethal doses (LD50 ) of isolates were lower compared to the isolates carrying two virulence genes. The challenge tests revealed that isolate W31 had the lowest lethal dose, causing 50% mortality at 4·5 × 103 colony-forming units (CFU) per ml. Furthermore, histopathology of Northern snakehead infected with Aeromonas strains showed necrosis and congestion in liver, spleen and kidney and also damage to the intestine. This study confirms that the Aeromonas strains isolated from healthy Northern snakehead may be a cause of concern for public health. SIGNIFICANCE AND IMPACT OF THE STUDY: Aeromonas species are widely distributed in aquatic environments and have considerable virulence potential. The aim of this study was to identify Aeromonas strains isolated from healthy Northern snakehead, and to investigate if Aeromonas species isolated from healthy fish potential pathogenicity with special reference to virulence and epidemiology studies.


Assuntos
Aeromonas/patogenicidade , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Fatores de Virulência/genética , Aeromonas/genética , Aeromonas/isolamento & purificação , Animais , Proteínas de Bactérias/genética , China/epidemiologia , DNA Girase/genética , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/patologia , Peixes , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/patologia , Humanos , Saúde Pública , Virulência/genética
7.
Microb Pathog ; 130: 81-94, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30849490

RESUMO

The genus Aeromonas comprises more than thirty Gram-negative bacterial species which mostly act as opportunistic microorganisms. These bacteria are distributed naturally in diverse aquatic ecosystems, where they are easily isolated from animals such as fish and crustaceans. A capacity for adaptation also makes Aeromonas able to colonize terrestrial environments and their inhabitants, so these microorganisms can be identified from different sources, such as soils, plants, fruits, vegetables, birds, reptiles, amphibians, among others. Infectious processes usually develop in immunocompromised humans; in fish and other marine animals this process occurs under conditions of stress. Such events are most often associated with incorrect practices in aquaculture. Aeromonas has element diverse ranges, denominated virulence factors, which promote adhesion, colonization and invasion into host cells. These virulence factors, such as membrane components, enzymes and toxins, for example, are differentially expressed among species, making some strains more virulent than others. Due to their diversity, no single virulence factor was considered determinant in the infectious process generated by these microorganisms. Unlike other genera, Aeromonas species are erroneously differentiated by conventional biochemical tests. Therefore, molecular assays are necessary for this purpose. Nevertheless, new means of identification have been considered in order to generate methods that, like molecular tests, can correctly identify these microorganisms. The main objectives of this review are to explain environmental and structural characteristics of the Aeromonas genus and to discuss virulence mechanisms that these bacteria use to infect aquatic organisms and humans, which are important aspects for aquaculture and public health, respectively. In addition, this review aims to clarify new tests for the precise identification of the species of Aeromonas, contributing to the exact and specific diagnosis of infections by these microorganisms and consequently the treatment.


Assuntos
Aeromonas/classificação , Aeromonas/isolamento & purificação , Doenças dos Animais/microbiologia , Microbiologia Ambiental , Infecções por Bactérias Gram-Negativas/veterinária , Doenças das Plantas/microbiologia , Aeromonas/patogenicidade , Animais , Técnicas Bacteriológicas/métodos , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Técnicas de Diagnóstico Molecular/métodos , Virulência , Fatores de Virulência/genética
8.
J Appl Microbiol ; 126(1): 288-299, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30218592

RESUMO

AIMS: Yesso scallop (Patinopecten yessoensis) is a popular seafood in Korea. Aeromonas spp., well-known pathogenic bacteria, has been reported in some molluscan shellfish, but it has not been studied in scallops so far. Therefore, we aimed to isolate, identify and characterize the Aeromonas spp. isolated from marketed Yesso scallops to estimate their potential risk to public health. METHODS AND RESULTS: Thirty-two Aeromonas spp. including A. hydrophila (n = 13), A. salmonicida (n = 11), A. media (n = 3), A. caviae (n = 2), A. veronii (n = 2) and A. enteropelogenes (n = 1) were isolated from 105 marketed scallops and tested for phenotypic pathogenicity, virulence genes and antimicrobial susceptibility. Mean total bacterial count of scallop meat was 1·34 × 104 CFU per gram. Slime production and lipase tests were positive in 97% of the isolates while DNase, protease, gelatinase, phospholipase and haemolysis were shown by 88, 88, 81, 88 and 72% of the isolates respectively. Eleven virulence genes were detected among Aeromonas spp. (act (75%), alt (59%), ast (47%), aerA (78%), lip (59%), ahyB (94%), ser (75%), hlyA (75%), fla (64%), gcat (84%) and ascV (23%)), and exu was negative in all isolates. Aeromonas hydrophila and A. salmonicida harboured ≥7 virulence genes and positive for enterotoxin genes, act, alt and ast. All the isolates were multidrug resistant and 100% resistant to ampicillin, colistin, vancomycin and cephalothin. Also, 30, 31, 20, 21, 29, 24, 27 and 27 of the isolates were resistant to piperacillin, clindamycin, erythromycin, nalidixic acid, imipenem, meropenem, trimethoprim-sulfamethoxazole and rifampicin respectively. CONCLUSIONS: It is obvious with our results that the Aeromonas spp. isolated from Yesso scallops are highly virulent and potentially pathogenic, whereas the multidrug resistance further expedite their importance. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first study reporting Aeromonas spp. in scallop. This implies that not only the common varieties like oysters, but other bivalves can also harbour potentially pathogenic aeromonads which may have impacts on consumer health.


Assuntos
Aeromonas , Pectinidae/microbiologia , Alimentos Marinhos/microbiologia , Aeromonas/efeitos dos fármacos , Aeromonas/genética , Aeromonas/isolamento & purificação , Aeromonas/patogenicidade , Animais , Antibacterianos/farmacologia , Filogenia , Virulência/genética
9.
J Fish Dis ; 42(2): 189-219, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30521094

RESUMO

Aeromonas spp. are ubiquitous in the aquatic environment, acting as facultative or obligate pathogens for fish. Identifying Aeromonas spp. is important for pathogenesis and prognosis in diagnostic cases but can be difficult because of their close relationship. Forty-four already characterized isolates of Aeromonas spp. were analysed by 16S rRNA gene sequencing, by gyrase B sequencing, by analysing their fatty acid profiles, by biochemical reactions and by MALDI-TOF MS. To determine their pathogenicity, cytotoxicity, adhesion to mucus and the expression of 12 virulence factors were tested. The susceptibility of the isolates towards 13 different antibiotics was determined. MALDI-TOF MS was found to be an acceptable identification method for Aeromonas spp. Although the method does not detect all species correctly, it is time-effective and entails relatively low costs and no other methods achieved better results. A high prevalence of virulence-related gene fragments was detected in almost all examined Aeromonas spp., especially in A. hydrophila and A. salmonicida, and most isolates exhibited a cytotoxic effect. Single isolates of A. hydrophila and A. salmonicida showed multiple resistance to antibiotics. These results might indicate the potentially pathogenic capacity of Aeromonas spp., suggesting a risk for aquatic animals and even humans, given their ubiquitous nature.


Assuntos
Aeromonas/classificação , Doenças dos Peixes/diagnóstico , Doenças dos Peixes/microbiologia , Muco/microbiologia , Aeromonas/genética , Aeromonas/patogenicidade , Animais , DNA Girase/química , Farmacorresistência Bacteriana , Ácidos Graxos/análise , Peixes , RNA Ribossômico 16S , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/veterinária , Fatores de Virulência
10.
Dev Comp Immunol ; 89: 131-140, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30125584

RESUMO

Hepcidin, a cysteine-rich antimicrobial peptide, is an important effector molecule in the innate immune system. Recently, Brachymystax lenok has become to be a valuable cold-water fish in China, particularly as the wild resources are rapidly declining. In this study, the hepcidin gene of Brachymystax lenok (Blhepc) has been cloned. The 870-bp mRNA contains a coding sequence (CDS) of 267 bp that encodes 88 amino acid residues. Amino acid sequence identities of Blhepc with hepcidin in Oncorhynchus mykiss, Salmo salar, and Hucho taimen were found to be 93.18%, 89.77% and 93.18%, respectively. Phylogenetic analysis indicated that Blhepc was clustered in the family Salmonidae. The putative signal peptide and the mature peptide contained 24 and 25 amino acid residues, respectively. The RXXR motif for recruitment of propeptide convertase was identified upstream of the mature peptide of Blhepc by sequence analysis. The N-terminal amino acid residues of the mature Blhepc peptide were Q-SH-L, a structure involved in regulating iron metabolism. Eight conserved cysteine residues in the mature peptide were held together by four disulfide bonds. Expression profiling of Blhepc indicated its highest level in the liver; its expression was stronger in males than in similar-aged females. Moreover, its expression in the liver increased significantly with age. Expression of Blhepc in six immune tissues showed increase in various degrees when challenged with Aeromonas salmonicida and Aeromonas hydrophila. A synthetic Blhepc mature peptide was validated to have significant antimicrobial activity against gram-negative and gram-positive bacteria and fungi in vitro. These results show that Blhepc may be an important component in the innate immunity of Brachymystax lenok, which could provide antimicrobial activities against invading pathogens.


Assuntos
Proteínas de Peixes/genética , Hepcidinas/genética , Salmonidae/genética , Aeromonas/imunologia , Aeromonas/patogenicidade , Sequência de Aminoácidos , Animais , China , Clonagem Molecular , Feminino , Proteínas de Peixes/química , Proteínas de Peixes/imunologia , Expressão Gênica , Hepcidinas/química , Hepcidinas/imunologia , Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata , Ferro/metabolismo , Masculino , Modelos Moleculares , Filogenia , Salmonidae/imunologia , Homologia de Sequência de Aminoácidos , Distribuição Tecidual
11.
J Fish Dis ; 41(10): 1559-1569, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30105751

RESUMO

Information about motile aeromonads from aquaculture systems of the Neotropical region is scarce. The aim of this study was to characterize motile Aeromonas isolated from ornamental and consumable fishes cultured in Uruguay. Biochemical and molecular methods were used for species identification. Antimicrobial susceptibility and the presence of virulence genes were evaluated. Genetic diversity was analysed by rep-PCR, and virulence of the most representative isolates was determined by calculating the fifty lethal dose in experimentally challenged fish (Australoheros facetus). Aeromonas hydrophila and A. veronii were the most prevalent identified species (38.2% and 32.4%, respectively), whereas A. allosacharophila, A. bestiarium, A. caviae and A. punctata were less prevalent. This study constitutes the first report of these last four species in Uruguay. All isolates were resistant to at least three antimicrobials, and 82.3% of them showed multidrug resistance. Virulence genotypes were correlated with the Aeromonas species and haemolytic activity. The genotype act+/alt+/ast+/ela+/lip+ was the most prevalent (26.5%). A correlation between virulence genotypes and Aeromonas species was found. A. punctata showed a clonal structure according to rep-PCR analysis, whereas other species showed high genetic diversity. The number of virulence genes of the isolates was related with virulence according to the experimental challenge assays.


Assuntos
Aeromonas/genética , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/patologia , Infecções por Bactérias Gram-Negativas/veterinária , Fenótipo , Aeromonas/efeitos dos fármacos , Aeromonas/isolamento & purificação , Aeromonas/patogenicidade , Animais , Antibacterianos/farmacologia , Aquicultura , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla , Doenças dos Peixes/microbiologia , Doenças dos Peixes/mortalidade , Variação Genética , Genótipo , Infecções por Bactérias Gram-Negativas/epidemiologia , Filogenia , Reação em Cadeia da Polimerase , Uruguai/epidemiologia , Virulência/genética , Fatores de Virulência/genética
12.
PLoS One ; 13(8): e0201428, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30110345

RESUMO

Many virulence factors have been described for opportunistic pathogens within the genus Aeromonas. Polymerase Chain Reactions (PCRs) are commonly used in population studies of aeromonads to detect virulence-associated genes in order to better understand the epidemiology and emergence of Aeromonas from the environment to host, but their performances have never been thoroughly evaluated. We aimed to determine diagnostic sensitivity and specificity of PCR assays for the detection of virulence-associated genes in a collection of Aeromonas isolates representative for the genetic diversity in the genus. Thirty-nine Aeromonas strains belonging to 27 recognized species were screened by published PCR assays for virulence-associated genes (act, aerA, aexT, alt, ascFG, ascV, ast, lafA, lip, ser, stx1, stx2A). In parallel, homologues of the 12 putative virulence genes were searched from the genomes of the 39 strains. Of the 12 published PCR assays for virulence factors, the comparison of PCR results and genome analysis estimated diagnostic sensitivities ranging from 34% to 100% and diagnostic specificities ranged from 71% to 100% depending upon the gene. To improve the detection of virulence-associated genes in aeromonads, we have designed new primer pairs for aerA/act, ser, lafA, ascFG and ascV, which showed excellent diagnostic sensitivity and specificity. Altogether, the analysis of high quality genomic data, which are more and more easy to obtain, provides significant improvements in the genetic detection of virulence factors in bacterial strains.


Assuntos
Aeromonas , Proteínas de Bactérias/genética , Genoma Bacteriano , Infecções por Bactérias Gram-Negativas/genética , Reação em Cadeia da Polimerase/métodos , Fatores de Virulência/genética , Aeromonas/genética , Aeromonas/patogenicidade , Infecções por Bactérias Gram-Negativas/diagnóstico , Humanos
13.
Pol J Microbiol ; 67(2): 137-149, 2018 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-30015452

RESUMO

Aeromonads have been isolated from varied environmental sources such as polluted and drinking water, as well as from tissues and body fluids of cold and warm-blooded animals. A phenotypically and genotypically heterogenous bacteria, aeromonads can be successfully identified by ribotyping and/or by analysing gyrB gene sequence, apart from classical biochemical characterization. Aeromonads are known to cause scepticemia in aquatic organisms, gastroenteritis and extraintestinal diseases such as scepticemia, skin, eye, wound and respiratory tract infections in humans. Several virulence and antibiotic resistance genes have been identified and isolated from this group, which if present in their mobile genetic elements, may be horizontally transferred to other naive environmental bacteria posing threat to the society. The extensive and indiscriminate use of antibiotics has given rise to many resistant varieties of bacteria. Multidrug resistance genes, such as NDM1, have been identified in this group of bacteria which is of serious health concern. Therefore, it is important to understand how antibiotic resistance develops and spreads in order to undertake preventive measures. It is also necessary to search and map putative virulence genes of Aeromonas for fighting the diseases caused by them. This review encompasses current knowledge of bacteriological, environmental, clinical and virulence aspects of the Aeromonas group and related diseases in humans and other animals of human concern.


Assuntos
Aeromonas/patogenicidade , Farmacorresistência Bacteriana Múltipla , Fatores de Virulência/genética , Aeromonas/genética , Animais , Antibacterianos/farmacologia , Diarreia/microbiologia , Gastroenterite/microbiologia , Infecções por Bactérias Gram-Negativas/complicações , Humanos , Filogenia , Sepse/microbiologia , Virulência , Microbiologia da Água
14.
J Fish Dis ; 41(10): 1529-1538, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30039866

RESUMO

A disease with white spots in internal organs of Nile tilapia occurred in Zhanjiang, southern China. Multiple, white nodules, 0.8-2.2 mm in diameter, were scattered throughout the liver, spleen and kidney of diseased fish. Signs of nodules reproduced after artificial infection with the isolated strain. Isolated bacteria were Gram-negative, facultative anaerobic, motile, short rod-shaped, with a length of 1.2-2.2 µm. Morphological and biochemical tests, as well as phylogenetic analysis, all strongly indicated that the isolate from tilapia is identical to Aeromonas schubertii (A. schubertii) which temporary named LF1708 strain. Antibiotic sensitivity assays showed the LF1708 is sensitive to 24 of 27 tested antibiotics. Pathogenicity test revealed that the isolate at the dose of 3.75 × 106 CFU/g killed 100% of experimental tilapia within 2 days and the dose of 1 × 107 CFU/g killed 100% of experimental zebrafish within 1 day. Histopathology of diseased tilapia infected with A. schubertii showed numerous necrotic lesions widely distributed in spleen, liver and kidney, and infiltration with a large number of bacteria. To our knowledge, this was the first report that associated A. schubertii with mortality in tilapia.


Assuntos
Aeromonas/patogenicidade , Ciclídeos/microbiologia , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Necrose/veterinária , Aeromonas/efeitos dos fármacos , Aeromonas/genética , Aeromonas/crescimento & desenvolvimento , Animais , Antibacterianos/farmacologia , China , DNA Girase/genética , RNA Polimerases Dirigidas por DNA/genética , Doenças dos Peixes/mortalidade , Doenças dos Peixes/patologia , Pesqueiros , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/patologia , Concentração de Íons de Hidrogênio , Rim/microbiologia , Rim/patologia , Fígado/microbiologia , Fígado/patologia , Necrose/microbiologia , Necrose/mortalidade , Filogenia , RNA Ribossômico 16S/genética , Salinidade , Baço/microbiologia , Baço/patologia , Peixe-Zebra/microbiologia
15.
Int J Mol Sci ; 19(7)2018 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-30036965

RESUMO

In order to understand the molecular basis underlying the host immune response of koi carp (Cyprinus carpio), Illumina HiSeqTM 2000 is used to analyze the muscle and spleen transcriptome of koi carp infected with Aeromonas sobria (A. sobria). De novo assembly of paired-end reads yielded 69,480 unigenes, of which the total length, average length, N50, and GC content are 70,120,028 bp, 1037 bp, 1793 bp, and 45.77%, respectively. Annotation is performed by comparison against various databases, yielding 42,229 (non-redundant protein sequence (NR): 60.78%), 59,255 (non-redundant nucleotide (NT): 85.28%), 35,900 (Swiss-Prot: 51.67%), 11,772 (clusters of orthologous groups (COG): 16.94%), 33,057 (Kyoto Encyclopedia of Genes and Genomes (KEGG): 47.58%), 18,764 (Gene Ontology (GO): 27.01%), and 32,085 (Interpro: 46.18%) unigenes. Comparative analysis of the expression profiles between bacterial challenge fish and control fish identifies 7749 differentially expressed genes (DEGs) from the muscle and 7846 DEGs from the spleen. These DEGs are further categorized with KEGG. Enrichment analysis of the DEGs and unigenes reveals major immune-related functions, including up-regulation of genes related with Toll-like receptor signaling, complement and coagulation cascades, and antigen processing and presentation. The results from RNA-Seq data are also validated and confirmed the consistency of the expression levels of seven immune-related genes after 24 h post infection with qPCR. Microsatellites (11,534), including di-to hexa nucleotide repeat motifs, are also identified. Altogether, this work provides valuable insights into the underlying immune mechanisms elicited during bacterial infection in koi carp that may aid in the future development of disease control measures in protection against A. sobria.


Assuntos
Aeromonas/patogenicidade , Carpas/metabolismo , Carpas/microbiologia , Infecções por Bactérias Gram-Negativas/metabolismo , Infecções por Bactérias Gram-Negativas/microbiologia , Animais , Carpas/imunologia , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Infecções por Bactérias Gram-Negativas/imunologia , Anotação de Sequência Molecular , Músculos/metabolismo , Baço/metabolismo , Transcriptoma/genética
16.
Fish Shellfish Immunol ; 80: 573-581, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29964197

RESUMO

Fish can be potentially co-infected by two or more bacterial strains, which can make synergistic influence on the virulence of infection. In this study, two opportunistic and multidrug resistant Aeromonas strains were isolated from wounds of morbid zebrafish with typical deep skin lesions similar to Motile Aeromonas Septicemia. Isolates were genetically identified as A. hydrophila and A. veronii by 16 S rRNA sequencing and phylogenetic analysis. Both isolates were positive for virulent genes (aerA, lip, ser, exu gcaT) and selected phenotypic tests (DNase, protease, gelatinase, lipase, biofilm production and ß-haemolysis). A. hydrophila and A. veronii had strong antibiotic resistance against ampicillin, tetracycline, nalidixic acid, kanamycin, erythromycin, clindamycin and trimethoprim-sulfamethoxazole. Histopathological studies revealed that co-infection causes severe necrosis and hypertrophy in the muscles, kidney and liver of zebrafish. Naturally co-infected zebrafish showed highly induced tnf-α, il-1ß, il-6, il-12, ifn, ifn-γ, cxcl18 b and ccl34a.4 at transcription level compared to healthy fish, suggesting virulence factors may activate immune and inflammatory responses of zebrafish. Experimentally infected zebrafish showed significantly higher mortality under co-infection with A. hydrohila and A. veronii (87%), followed by individual challenge of A. hydrophila (72%) or A. veronii (67%) suggesting that virulence of A. hydrophila have greater pathogenicity than A. veronii during co-infection.


Assuntos
Aeromonas , Coinfecção , Doenças dos Peixes , Infecções por Bactérias Gram-Negativas , Peixe-Zebra , Aeromonas/efeitos dos fármacos , Aeromonas/genética , Aeromonas/patogenicidade , Animais , Antibacterianos/farmacologia , Coinfecção/genética , Coinfecção/imunologia , Coinfecção/veterinária , Citocinas/genética , Farmacorresistência Bacteriana , Doenças dos Peixes/genética , Doenças dos Peixes/imunologia , Doenças dos Peixes/patologia , Proteínas de Peixes/genética , Infecções por Bactérias Gram-Negativas/genética , Infecções por Bactérias Gram-Negativas/imunologia , Infecções por Bactérias Gram-Negativas/patologia , Infecções por Bactérias Gram-Negativas/veterinária , Rim/patologia , Fígado/patologia , Músculos/patologia , RNA Mensageiro/metabolismo , RNA Ribossômico 16S/genética , Virulência/genética , Peixe-Zebra/genética , Peixe-Zebra/imunologia , Peixe-Zebra/microbiologia
17.
Dis Aquat Organ ; 129(2): 107-116, 2018 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-29972371

RESUMO

Aeromonas dhakensis (Ad) CAIM 1873 growth was evaluated at different conditions and antibiotic susceptibility. Mortality and histopathological damages in hybrid tilapia Oreochromis niloticus × O. mossambicus, and virulence factors caused by Ad bacterial cells and extracellular products (ECPs) were evaluated, and the whole genome was obtained. Ad grew between 0.0 and 5.5% NaCl at a pH of between 4 and 10 and from 4 to 37°C. The lowest minimum inhibitory concentration was found for enrofloxacin (<5 µg ml-1), and bacteria were resistant to erythromycin, amoxicillin and ampicillin. Ad bacterial cells (1.86 × 105 cells g-1) and ECPs (0.462 µg protein fish-1) were highly virulent to challenged hybrid tilapia and caused over 80% mortality at 24 h. The primary clinical sign caused was haemorrhage, and damage was most marked in the spleen, liver, kidney and brain of fish challenged with bacterial cells. To our knowledge, this is the first report that Ad causes pyknotic and karyorrhectic nuclei of erythrocytes in the internal organs of hybrid tilapia, which was the most striking histopathological observation. The virulence of Ad to hybrid tilapia may be primarily related to the activity of haemolysins (hlyA genes) and cytotoxins (aerolysin aerA), along with the production of siderophores and proteases. We also found ß-lactamase, tetracycline and multiple antibiotic resistance genes, as well as adherence, iron acquisition, toxins (aerolysin family, haemolysins) and diverse protease genes.


Assuntos
Aeromonas/patogenicidade , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Tilápia/genética , Aeromonas/genética , Aeromonas/metabolismo , Animais , Doenças dos Peixes/patologia , Regulação Bacteriana da Expressão Gênica , Genoma Bacteriano , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/patologia , Virulência
18.
J Aquat Anim Health ; 30(3): 201-209, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29799641

RESUMO

In response to population declines of North American Burbot Lota lota maculosa (hereafter, Burbot), conservation aquaculture methods have been developed for this species. In general, Burbot are relatively resistant to many salmonid pathogens; however, cultured juvenile Burbot have experienced periodic epizootic disease outbreaks during production. A series of trials was conducted to determine the virulence of select bacteria isolated from juvenile Burbot after outbreaks that occurred in 2012 and 2013 at the University of Idaho's Aquaculture Research Institute. Initial clinical diagnostics and sampling resulted in the isolation of numerous putative bacterial pathogens. To determine which bacteria were the most likely causative agents contributing to these epizootics, juvenile Burbot received intraperitoneal (IP) injections of select bacteria in log-phase growth. Mortality associated with specific isolates was recorded, and more comprehensive challenges followed this initial screening. These challenges used side-by-side IP and immersion methods to expose Burbot to potential pathogens. The challenges resulted in significantly higher mortalities in fish after IP injection with two Aeromonas sp. isolates compared to controls, but no significant difference in mortality for immersion-challenged groups was observed. Results demonstrate that two Aeromonas sp. isolates cultured from the epizootics are virulent to Burbot.


Assuntos
Aeromonas/fisiologia , Aeromonas/patogenicidade , Doenças dos Peixes/microbiologia , Gadiformes , Infecções por Bactérias Gram-Negativas/veterinária , Aeromonas/isolamento & purificação , Animais , Bactérias/isolamento & purificação , Bactérias/patogenicidade , Doenças dos Peixes/epidemiologia , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/microbiologia
19.
J Food Prot ; 81(6): 1015-1021, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29757009

RESUMO

The aim of this study was to determine the public health significance of hemolytic Aeromonas species isolated from 213 food samples in Egypt, based on their virulence and antimicrobial-resistance potential. We recovered 63 strains, isolated from fish, raw milk, karish cheeses, and ras cheese in 29 (31.18%) of 93, 10 (25.00%) of 40, 13 (32.50%) of 40, and 11 (27.50%) of 40 samples, respectively. The most prevalent virulence gene was alt (50.79%), followed by aerA (34.92%), asa1 (39.68%), ahh1 (20.63%), act (11.11%), and ast (3.17%). Thirteen strains screened in this study carried no hemolysin gene, but only the alt gene, and another eight hemolytic strains screened, carried no virulence gene. The virulence signatures " ahh1+ aerA" and " alt+ act," in which the genes interact synergistically to induce severe diarrhea, were detected in two and four strains, respectively. Most showed resistance to third-generation cephalosporins, aztreonam, and imipenem, which indicates the complexity of the ß-lactamase production in our hemolytic Aeromonas strains. Fourteen (22.22%) of 63 strains carried one or more antimicrobial-resistance markers, including the blaCTX-M, blaTEM, tet(A), tet(E), and intI1 genes, which were detected in 6.34, 3.17, 3.17, 4.76, and 14.28% of isolates, respectively. In conclusion, the majority of hemolytic Aeromonas strains isolated from the intestinal contents of healthy fish and naturally contaminated milk and cheeses were not commensal but had developed multidrug-resistance and virulence profiles, indicating an emerging potential health risk. Importantly, screening for certain hemolysin genes may not be reliable in predicting the pathogenic potential of Aeromonas species and, thereby, the safety of analyzed foods. Our findings indicate that specific criteria are required for the phenotypic and molecular analysis of Aeromonas species in food items, particularly those eaten without further treatment, to ensure their safety.


Assuntos
Aeromonas , Resistência a Múltiplos Medicamentos , Fatores de Virulência , Aeromonas/efeitos dos fármacos , Aeromonas/genética , Aeromonas/patogenicidade , Animais , Egito , Humanos , Virulência/genética
20.
Proc Natl Acad Sci U S A ; 115(4): 726-731, 2018 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-29311327

RESUMO

Mucosal surfaces represent critical routes for entry and exit of pathogens. As such, animals have evolved strategies to combat infection at these sites, in particular the production of mucus to prevent attachment and to promote subsequent movement of the mucus/microbe away from the underlying epithelial surface. Using biochemical, biophysical, and infection studies, we have investigated the host protective properties of the skin mucus barrier of the Xenopus tropicalis tadpole. Specifically, we have characterized the major structural component of the barrier and shown that it is a mucin glycoprotein (Otogelin-like or Otogl) with similar sequence, domain organization, and structural properties to human gel-forming mucins. This mucin forms the structural basis of a surface barrier (∼6 µm thick), which is depleted through knockdown of Otogl. Crucially, Otogl knockdown leads to susceptibility to infection by the opportunistic pathogen Aeromonas hydrophila To more accurately reflect its structure, tissue localization, and function, we have renamed Otogl as Xenopus Skin Mucin, or MucXS. Our findings characterize an accessible and tractable model system to define mucus barrier function and host-microbe interactions.


Assuntos
Mucinas/metabolismo , Membrana Mucosa/metabolismo , Xenopus/metabolismo , Aeromonas/patogenicidade , Animais , Proteínas de Membrana/metabolismo , Mucinas/fisiologia , Membrana Mucosa/fisiologia , Muco/metabolismo , Muco/fisiologia , Pele/metabolismo , Xenopus/imunologia , Xenopus/fisiologia , Proteínas de Xenopus/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA