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1.
Microbiol Immunol ; 66(6): 307-316, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35274358

RESUMO

Rhodococcus equiis the causative agent of pyogenic pneumonia in foals, and a virulence-associated protein A (VapA) encoded on the pVAPA virulence plasmid is important for its pathogenicity. In this study, we analyzed the virulence of R. equi strain U19, originally isolated in the Netherlands in 1997 and the genetic characteristics of the pVAPA_U19 plasmid. U19 expressed VapA that was regulated by temperature and pH and underwent significant intracellular proliferation in macrophages. The restriction fragment length polymorphism of pVAPA_U19 digested with EcoRI was similar to that of pREAT701 (85 kb Type I) harbored by R. equi ATCC33701, although the band pattern at 10-20 kb differed. Whole-genome sequencing showed that pVAPA_U19 was 51,684 bp in length and that the vapA pathogenicity island region and the replication/participation were almost identical to those in pREAT701. By contrast, the open reading frames (ORF26-ORF45) genes of pREAT701 (approximately 29,000 bp) were absent from pVAPA_U19. In this lacking region, mobility (MOB) genes, such as relaxase, which allow conjugative DNA processing, and the mating pair formation (MPF) genes, which are a form of the Type IV secretion system and provide the mating channel, were present. Coculture between U19 and five different recipient strains (two plasmid-cured strains and three cryptic plasmid-harboring strains) demonstrated that pVAPA_U19 could not support conjugation. Therefore, pVAPA_U19 does not differ significantly from the previously reported pVAPA in terms of virulence and plasmid replication and maintenance but is a nonmobilizable plasmid unable to cause conjugation because of the absence of genes related to MOB and MPF.


Assuntos
Doenças dos Cavalos , Rhodococcus equi , Rhodococcus , Animais , Proteínas de Bactérias/genética , Cavalos/genética , Plasmídeos/genética , Rhodococcus/genética , Rhodococcus equi/genética , Virulência/genética , Fatores de Virulência/genética
2.
Int J Med Microbiol ; 311(6): 151519, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34280738

RESUMO

Rhodococcus equi is a saprophytic soil bacterium and intracellular pathogen that causes refractory suppurative pneumonia in foals and has emerged as a pathogenic cause of zoonotic disease. Several studies have reported human infections caused by R. equi harboring a recently described third type of virulence plasmid, the ruminant-associated pVAPN, which carries the vapN virulence determinant. Herein, we analyzed pathogenicity and genomic features of nine vapN-harboring R. equi isolated from human patients with and without HIV/AIDS. Four of these strains showed significant VapN production and proliferation in cultured macrophages. These strains were lethally pathogenic after inoculation with 1.0 × 108 CFU in mice and reproduced a necrotizing granulomatous inflammation in the liver and spleen similar to that observed in humans. Additionally, we determined entire genome sequences of all nine strains. Lengths of sequences were 5.0-5.3 Mbp, and GC contents were 68.7 %-68.8 %. All strains harbored a 120- or 125-kbp linear plasmid carrying vapN (Type I or Type II pVAPN) classified on the basis of differences in the distal sequences on the 3' side. Interestingly, VapN production differed significantly among strains harboring nearly identical types of pVAPN with variation limited to several SNPs and short base pair indels. The pVAPN sequences possessed by the VapN-producing strains did not retain any common genetic characteristics, and more detailed analyses, including chromosomal genes, are needed to further elucidate the VapN expression mechanism.


Assuntos
Infecções por Actinomycetales , Rhodococcus equi , Rhodococcus , Infecções por Actinomycetales/veterinária , Animais , Genômica , Cavalos , Humanos , Camundongos , Plasmídeos/genética , Rhodococcus equi/genética , Virulência
3.
Microb Pathog ; 160: 105186, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34509529

RESUMO

Rhodococcus equi is a well-known intracellular facultative bacterium that is opportunistic in nature, and a contagious disease-causing agent of pyogranulomatous infections in humans and multihost animals. Feline rhodococcosis is an uncommon or unnoticed clinical condition, in which the organism is usually refractory to conventional antimicrobial therapy. The pathogenicity of the agent is intimately associated with plasmid-governed infectivity, which is attributed to the presence of plasmid-encoded virulence-associated proteins (Vap). Three host-adapted virulence plasmid types (VAPs) have been distinguished to date: pVAPA, pVAPB, and pVAPN, whose infections are related to equine, pig, and bovine or caprine origin, respectively, while humans are infected by all three VAP types. Most virulence studies with R. equi plasmid types in animals involve livestock species. Conversely, data on the pathogenicity and human relevance of the virulence plasmid profile of R. equi isolated from cats remains unclear. This report describes a case of cellulitis-related R. equi that harbors the pVAPA-type in a cat with cutaneous lesion. Long-term therapy of the cat using marbofloxacin, a broad-spectrum third-generation fluoroquinolone, resulted effectiveness. pVAPA is a host-adapted virulent type that has been associated predominantly with pulmonary foal infections. Our cat had a history of contact with other cats, livestock (including horses), and farm environment that could have favored the transmission of the pathogen. Besides no clear evidence of cat-to-humans transmission of the pathogen, the identification of R. equi harboring pVAPA-type in a cat with cutaneous abscessed lesion represent relevance in human health because this virulent type has been described in people worldwide with clinical rhodococcal disorders.


Assuntos
Infecções por Actinomycetales , Celulite (Flegmão) , Rhodococcus equi , Infecções por Actinomycetales/veterinária , Animais , Proteínas de Bactérias/genética , Gatos , Celulite (Flegmão)/microbiologia , Celulite (Flegmão)/veterinária , Plasmídeos/genética , Rhodococcus equi/genética , Fatores de Virulência/genética
4.
Food Microbiol ; 92: 103588, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32950172

RESUMO

Staphylococcal enterotoxins (SEs) are extracellular proteins, produced mainly by Staphylococcus aureus, which cause staphylococcal food poisoning (SFP) when ingested. Here, a novel SE was identified from two strains, which were identified as the causative microbes of the SFP outbreak that occurred in Tokyo in 2004. Both strains harbored the SEA gene, but its production was lower than that of other SEA-producing SFP isolates. Whole-genome sequencing analysis demonstrated that both strains harbored a SE-like gene besides sea. Phylogenetic analysis revealed that the amino acid sequence deduced from the SE-like gene belonged to the SEB group. Therefore, this gene was presumed to be a novel SE gene and termed "SE02." The stability of SE02 against heating and proteolytic digestions was a little different from that of SEA. SE02 has both superantigenic and emetic bioactivities. Namely, SE02 activated mouse splenocytes and exhibited emetic activity in the common marmoset. SE02 mRNA was highly expressed in both isolates during the exponential phase of cultivation. In addition, SE02 protein was produced at 20 °C and 25 °C, which reflects the actual situation of SFP. SE02 appears to be a novel emetic toxin that was likely the causative toxin in combination with SEA in the SFP outbreak.


Assuntos
Enterotoxinas/toxicidade , Intoxicação Alimentar Estafilocócica/microbiologia , Staphylococcus aureus/metabolismo , Animais , Callithrix , Surtos de Doenças , Enterotoxinas/genética , Enterotoxinas/metabolismo , Feminino , Genoma Bacteriano , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Filogenia , Intoxicação Alimentar Estafilocócica/epidemiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Tóquio/epidemiologia
5.
Mol Microbiol ; 98(4): 712-26, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26239091

RESUMO

Campylobacter jejuni, one of the most common causes of gastroenteritis worldwide, is transmitted to humans through poultry. We previously reported that Lactobacillus gasseri SBT2055 (LG2055) reduced C. jejuni infection in human epithelial cells in vitro and inhibited pathogen colonization of chickens in vivo. This suggested that the LG2055 adhesion and/or co-aggregation phenotype mediated by cell-surface aggregation-promoting factors (APFs) may be important for the competitive exclusion of C. jejuni. Here, we show that cell surface-associated APF1 promoted LG2055 self-aggregation and adhesion to human epithelial cells and exhibited high affinity for the extracellular matrix component fibronectin. These effects were absent in the apf1 knockout mutant, indicating the role of APF1 in LG2055-mediated inhibition of C. jejuni in epithelial cells and chicken colonization. Similar to APF1, APF2 promoted the co-aggregation of LG2055 and C. jejuni but did not inhibit C. jejuni infection. Our data suggest a pivotal role for APF1 in mediating the interaction of LG2055 with human intestinal cells and in inhibiting C. jejuni colonization of the gastrointestinal tract. We thus provide new insight into the health-promoting effects of probiotics and mechanisms of competitive exclusion in poultry. Further research is needed to determine whether the probiotic strains reach the epithelial surface.


Assuntos
Antibiose , Aderência Bacteriana , Proteínas de Bactérias/metabolismo , Campylobacter jejuni/fisiologia , Lactobacillus/química , Lactobacillus/fisiologia , Animais , Proteínas de Bactérias/genética , Infecções por Campylobacter/microbiologia , Infecções por Campylobacter/prevenção & controle , Infecções por Campylobacter/terapia , Campylobacter jejuni/crescimento & desenvolvimento , Galinhas/microbiologia , Células Epiteliais/microbiologia , Humanos , Intestinos/microbiologia , Probióticos
6.
Microbiol Immunol ; 59(8): 495-9, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26094962

RESUMO

A virulence plasmid of Rhodococcus equi harbors the vap mutigene family. Here it is shown that transcription of vap gene family members other than vapA (vapD, vapE and vapG) is regulated by temperature and pH and abolished when either virS or virR is deleted. Expression of VirS in the absence of functional VirR was found to increase the transcription of vap genes to the amount expressed in the presence of VirR. These findings suggest that transcription of vap genes is regulated by VirS and that VirR is involved in the mechanism of transcriptional responses to temperature and pH.


Assuntos
Regulação Bacteriana da Expressão Gênica , Genes Reguladores , Família Multigênica , Rhodococcus equi/genética , Ativação Transcricional/efeitos dos fármacos , Ativação Transcricional/efeitos da radiação , Fatores de Virulência/biossíntese , Concentração de Íons de Hidrogênio , Plasmídeos , Rhodococcus equi/efeitos dos fármacos , Rhodococcus equi/efeitos da radiação , Temperatura , Transcrição Gênica , Virulência
7.
BMC Microbiol ; 14: 243, 2014 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-25281192

RESUMO

BACKGROUND: Rhodococcus equi is an important pulmonary pathogen in foals and in immunocompromised individuals. Virulent R. equi strains carry an 80-90 kb virulence plasmid that expresses the virulence-associated protein A (VapA). VapA expression is regulated by temperature and pH. The LysR-type transcriptional regulator, VirR, is involved in the regulation of the vapA gene. To examine the mechanism underlying transcriptional regulation of vapA, we characterized an R. equi mutant in which another putative transcriptional regulator encoded on the virulence plasmid, VirS, was deleted. RESULTS: Deletion of virS reduced vapA promoter activity to non-inducible levels. Complementary expression of VirS in the virS deletion mutant restored transcription at the PvapA promoter, even under non-inducing conditions (30°C and pH 8.0). In addition, VirS expression increased PvapA promoter activity in the absence of functional VirR. Further, transcription of the icgA operon containing virS was regulated by pH and temperature in the same manner as vapA. CONCLUSIONS: This study suggests that VirS is required for VapA expression and that regulation of PvapA-promoter activity may be achieved by controlling VirS expression levels.


Assuntos
Proteínas de Bactérias/biossíntese , Regulação Bacteriana da Expressão Gênica , Rhodococcus equi/genética , Fatores de Transcrição/metabolismo , Deleção de Genes , Concentração de Íons de Hidrogênio , Plasmídeos , Regiões Promotoras Genéticas , Rhodococcus equi/efeitos dos fármacos , Rhodococcus equi/efeitos da radiação , Temperatura , Fatores de Transcrição/genética
8.
Nihon Saikingaku Zasshi ; 79(1): 15-24, 2024.
Artigo em Japonês | MEDLINE | ID: mdl-38382971

RESUMO

Rhodococcus equi is a facultative intracellular gram-positive coccobacillus which is a well-known cause of foal pneumonia and/or enteritis in equine veterinary medicine. More than 300 cases of R. equi infection have been reported since the first description of human disease in 1968. Most patients who become infected with R equi are immunocompromised, such as those infected with human immunodeficiency virus (HIV), recipients of organ transplantation, and patients receiving cancer treatment. However, there are increasing reports of the immunocompetent hosts. The pathogenicity of R. equi has been attributed to the presence of plasmid-encoded virulence-associated proteins (Vap). To date, three host-associated virulence plasmid types of R. equi have been identified as follows: the circular pVAPA and pVAPB, related, respectively, to equine and porcine isolates in 1991 and 1995, and a recently described linear pVAPN plasmid associated with bovine and caprine strains in 2015. More recently, these three plasmid types have been re-found in the human isolates which were isolated during 1980s to 1990s. Not only horses, but also pigs, goats, cattle and their environment should be considered as a potential source of R. equi for humans. In this review, we shed light on the current understanding of R. equi as an emerging zoonotic pathogen.


Assuntos
Rhodococcus equi , Fatores de Virulência , Humanos , Animais , Cavalos , Bovinos , Suínos , Fatores de Virulência/genética , Rhodococcus equi/genética , Cabras , Plasmídeos/genética
9.
J Vet Med Sci ; 86(6): 600-605, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38631887

RESUMO

To investigate the etiological role of vapB-positive Rhodococcus equi in pigs, R. equi was isolated from the submaxillary lymph nodes with or without macroscopically detectable lesions of apparently healthy growing-finishing pigs at a slaughterhouse in Toyama Prefecture, Japan. R. equi was isolated from 57 (24.6%) of 232 pigs with macroscopically detectable lymph node lesions, and 56 (98.2%) of the 57 isolates were vapB-positive. R. equi was isolated from 10 (2.4%) of 420 pigs without lymph node lesions, and six (60%) of the 10 isolates were vapB-positive. Plasmid DNA was isolated from the 62 vapB-positive isolates and digested with EcoRI and NsiI to obtain the plasmid profile. Fifty-two (83.9%), three (4.8%), and four (6.5%) isolates contained pVAPB subtypes 1, 2, and 3, respectively, while the remaining three isolates were of pVAPB subtypes 9, 13, and 14, respectively. Twelve specimens from lymph nodes with macroscopically detectable lesions were randomly selected for histopathological staining. Granulomatous lesions resembling tuberculosis were found in 11 of the 12 specimens, and the remaining specimen showed typical foci of malakoplakia in the lymph node. The isolation rates of R. equi and vapB-positive R. equi from lymph nodes with macroscopically detectable lesions were significantly higher (P<0.05) than those of lymph nodes without lesions, suggesting an etiologic association between vapB-positive R. equi and macroscopically detectable granulomatous lesions in porcine submaxillary lymph nodes. Previous reports on the prevalence of vapB-positive R. equi in pigs are reviewed and discussed.


Assuntos
Infecções por Actinomycetales , Linfonodos , Rhodococcus equi , Doenças dos Suínos , Animais , Rhodococcus equi/isolamento & purificação , Rhodococcus equi/genética , Linfonodos/microbiologia , Linfonodos/patologia , Doenças dos Suínos/microbiologia , Doenças dos Suínos/patologia , Suínos , Japão/epidemiologia , Infecções por Actinomycetales/veterinária , Infecções por Actinomycetales/microbiologia , Infecções por Actinomycetales/patologia , Proteínas de Bactérias/genética , Plasmídeos , Granuloma/veterinária , Granuloma/microbiologia , Granuloma/patologia
10.
Vet Microbiol ; 295: 110132, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38838383

RESUMO

Rhodococcus equi has recently been identified in various animals, including ruminants. Several studies have highlighted the emergence of pVAPN-harboring strains, isolated from multiple abscesses, in the liver and lungs of ruminants. Epidemiological evidence strongly suggests that pVAPN-harboring strains are pathogenic in ruminants. This study aims to replicate the disease in goats through experimental infection. Intravenous administration of the pVAPN-harboring strain (Yokkaichi), pVAPA-harboring strain (ATCC33701), and pVAPN-cured strain (Yokkaichi_P-), each at 1.0 × 107 CFU/head, was conducted in 24-month-old goats (n = 1 per group). During the observation period, goats treated with Yokkaichi or ATCC33701 exhibited transient increases in body temperature and white blood cell count, alongside a decrease in body weight from the administration day. Conversely, goats treated with Yokkaichi_P- displayed no significant changes in these values. The Yokkaichi-treated goat demonstrated a >10-fold increase in anti-VapN antibody titers from 11 to 14 days postadministration, whereas the other two goats exhibited no variation in anti-VapA and VapN antibody titers. Pathological autopsy analysis of organs harvested 28 days postadministration revealed no characteristic lesions on gross examination. However, the inoculated strain (vapN-positive R. equi) was exclusively recovered from the tracheobronchial lymph node in the Yokkaichi-treated goat. Immunohistochemistry detected a VapN-positive reaction in the tracheobronchial lymph node, confirming latent infection despite the absence of dramatic suppurative lesions seen in ruminants. Overall, this study highlights the latent infection in lymph nodes induced by the pVAPN-harboring strain, despite the absence of overt pathological manifestations.


Assuntos
Infecções por Actinomycetales , Doenças das Cabras , Cabras , Linfonodos , Rhodococcus equi , Animais , Rhodococcus equi/patogenicidade , Linfonodos/microbiologia , Linfonodos/patologia , Infecções por Actinomycetales/veterinária , Infecções por Actinomycetales/microbiologia , Infecções por Actinomycetales/patologia , Doenças das Cabras/microbiologia , Doenças das Cabras/patologia , Proteínas de Bactérias/genética , Anticorpos Antibacterianos/sangue
11.
Folia Microbiol (Praha) ; 69(2): 347-360, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37405631

RESUMO

The populations of Japanese deer and boar have increased dramatically and have a serious impact on farming and mountain villages. Although the Japanese government promotes the use of captured wild animals, game meat is not subject to sanitary control considering that it is not subject to meat inspection or quality control. Here, we have attempted to isolate Staphylococcus aureus, a typical foodborne pathogen, as a part of an investigation of contamination in the meats of wild animals and their processing stages. We examined 390 samples of deer feces, 117 samples of wild boar feces, and 75 samples of disemboweled deer meat for isolation of S. aureus; ultimately, 30 (positive rate: 7.7%), 2 (1.7%), and 21 (28.0%) strains were isolated, respectively, from the samples. The genome sequences of these isolates were analyzed and were subjected to multilocus sequence typing. We identified 12 new sequence types (STs) and a dominant population of S. aureus with a characteristic genetic background in wild animals, namely, the ST groups derived from CC121 (number of strains = 39). These strains did not harbor the enterotoxin gene or only harbored egc-related enterotoxin, which is of low involvement in Staphylococcal food poisoning. However, one ST2449 strain, which produces causative enterotoxins, was isolated from a deer's feces. Since there are several common STs isolated from feces and dismembered meat and because fecal contamination during dismemberment is suspected, continuous monitoring and guidance for improving sanitary management conditions during processing and handling of the meat are highly warranted with immediate effect.


Assuntos
Cervos , Infecções Estafilocócicas , Animais , Suínos , Staphylococcus aureus/genética , Animais Selvagens , Enterotoxinas/genética , Infecções Estafilocócicas/epidemiologia , Carne , Fezes , Microbiologia de Alimentos
12.
Vet Microbiol ; 287: 109919, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38000208

RESUMO

Virulent Rhodococcus equi strains expressing virulence-associated 15-17 kDa protein (VapA) and having a large virulence plasmid (pVAPA) of 85-90 kb containing vapA gene are pathogenic for horses. In the last two decades, following pVAPA, two host-associated virulence plasmid types of R. equi have been discovered: a circular plasmid, pVAPB, associated with porcine isolates in 1995, and a recently detected linear plasmid, pVAPN, related to bovine and caprine isolates. Molecular epidemiological studies of R. equi infection in foals on horse-breeding farms in Japan and many countries around the world have been conducted in the last three decades, and the epidemiological studies using restriction enzyme digestion patterns of plasmid DNAs from virulent isolates have shown 14 distinct pVAPA subtypes and their geographical preference. This short review summarizes previous reports regarding equine-associated pVAPA subtypes in the world and discusses their geographic distribution from the standpoint of horse movements.


Assuntos
Infecções por Actinomycetales , Doenças dos Bovinos , Doenças das Cabras , Doenças dos Cavalos , Rhodococcus equi , Doenças dos Suínos , Animais , Cavalos , Bovinos , Suínos , Rhodococcus equi/genética , Cabras , Fatores de Virulência/genética , Infecções por Actinomycetales/epidemiologia , Infecções por Actinomycetales/veterinária , Plasmídeos/genética , Proteínas de Bactérias/genética , Doenças dos Cavalos/epidemiologia
13.
Microbiol Spectr ; 11(6): e0072923, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-37800907

RESUMO

IMPORTANCE: Rhodococcus equi can cause infection in ruminants, and its pathogenicity is suggested to be associated with VapN. Despite its wide distribution, no immunological diagnostic method has been developed for VapN-producing R. equi. Against this background, we attempted to develop monoclonal antibodies targeting VapN and assess their application in immunostaining. In the study, mice were immunized with recombinant VapN, and cell fusion and cloning by limiting dilution permitted the generation of three antibody-producing hybridomas. The utility of the antibodies produced from the hybridomas in immunostaining was demonstrated using an infected mouse model, and the antibodies were further applied to previously reported cases of R. equi infection in goats and cattle. Although the 4H4 antibody induced the strongest reactions, the reactivity of two other antibodies was improved by antigen retrieval. Our monoclonal antibodies will be utilized to support the definitive diagnosis of suspected R. equi infection, including cases that were previously missed.


Assuntos
Infecções por Actinomycetales , Rhodococcus equi , Bovinos , Animais , Camundongos , Virulência , Anticorpos Monoclonais , Infecções por Actinomycetales/diagnóstico , Infecções por Actinomycetales/veterinária , Anticorpos Antibacterianos
14.
Microbiol Spectr ; 10(3): e0075822, 2022 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-35638814

RESUMO

A previously reported method for evaluating the intracellular growth of Rhodococcus equi using enhanced green fluorescent protein is unsuitable for the quantitative evaluation of the entire sample because the signal can be detected only in the excitation region. Therefore, we created an autobioluminescent R. equi using luciferase (luxABCDE). First, we connected luxABCDE to the functional promoter PaphII and introduced it into the chromosomes of ATCC33701 and ATCC33701_P-. Luminescence was detected in both transformants, and a correlation between the bacterial number and luminescence intensity in the logarithmic phase was observed, indicating that luxABCDE is functionally and quantitatively expressed in R. equi. The luminescence of ATCC33701 was significantly higher than that of ATCC33701_P- at 24 h after infection with J774A.1. Next, RNA-Seq analysis of ATCC33701 to search for endogenous high-expression promoters resulted in the upstream sequences of RS29370, RS41760, and vapA being selected as candidates. Luminescence was detected in each transformant expressing the luxABCDE using these upstream sequences. We examined the luminescence intensity by coexpressing the frp gene, an enhancer of the luciferase reaction, with luxABCDE. The luminescence intensity of the coexpressing transformant was significantly enhanced in J774A.1 compared with the non-coexpressing transformant. Finally, we examined the luminescence in vivo. The luminescence signals in the organs peaked on the third day following the administration of ATCC33701 derivatives in mice, but no luminescence signal was detected when the ATCC33701_P- derivative was administered. The autologous bioluminescent method described herein will enhance the in vitro and in vivo quantitative analysis of R. equi proliferation. IMPORTANCE We established an autologous bioluminescent strain of R. equi and a method to evaluate its proliferation in vitro and in vivo quantitatively. This method overcomes the weakness of the fluorescence detection system that only measures the site of excitation light irradiation. It is expected to be used as an in vitro and in vivo growth evaluation method with excellent quantitative properties. In addition, it was suggested that the selection of a promoter that expresses luxABCDE could produce a luminescence with high intensity. Although this method needs further improvement, such as creating transformants that can maintain high luminescence intensity regardless of environmental changes such as temperature fluctuations, it is possible to observe bacterial growth over time in mice without killing them. Therefore, this method can be used to not only evaluate the pathogenicity of various wild and gene-deficient strains but also to screen preventive and therapeutic methods such as vaccines.


Assuntos
Infecções por Actinomycetales , Rhodococcus equi , Infecções por Actinomycetales/microbiologia , Infecções por Actinomycetales/prevenção & controle , Animais , Proteínas de Bactérias/genética , Camundongos , Rhodococcus equi/genética , Fatores de Virulência/genética
15.
Vet Microbiol ; 267: 109373, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35217354

RESUMO

Tracheal washing fluid was collected from 170 foals at 28 and 35 d old from February to July in a foaling season on horse-breeding farms with sporadic rhodococcosis in Japan and was investigated by quantitative culture. The history of the 170 foals followed up for the next few months. The proportion of R. equi-positive foals at 28 and 35 d old was significantly increased according to the birth month. Furthermore, the mean number of R. equi in the tracheal washing fluid of each month group increased according to their birth month with the rise in outside temperature. During the follow-up observation, 9/30 foals (30.0 %) born in February showed the first clinical signs at 56 ± 8 d old, 21/61 foals (34.4 %) born in March showed the signs at 37 ± 3 d old, 15/49 foals (30.6 %) born in April showed the signs at 39 ± 2 d old, and 7/30 foals (23.3 %) born in May showed signs at 44 ± 3 d old. Two sick foals (6.7 %) born in February, 19 sick foals (31.1 %) born in March, 15 sick foals (30.6 %) born in April, and 6 sick foals (20.0 %) born in May showed a positive culture of R. equi at 28 or 35 d old. The present study revealed that birth month is associated with the initial colonization of R. equi in the trachea of newborn foals on farms with sporadic rhodococcosis in Japan. Therefore, birth month might be a risk factor for developing R. equi pneumonia in foals.


Assuntos
Infecções por Actinomycetales , Doenças dos Cavalos , Rhodococcus equi , Infecções por Actinomycetales/veterinária , Animais , Animais Recém-Nascidos , Fazendas , Doenças dos Cavalos/epidemiologia , Cavalos , Japão/epidemiologia , Traqueia
16.
Microbiology (Reading) ; 157(Pt 5): 1279-1289, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21292743

RESUMO

Campylobacter jejuni is a leading cause of bacterial gastroenteritis in humans and a commensal bacterium of the intestinal tracts of animals, especially poultry. Chemotaxis is an important determinant for chicken colonization of C. jejuni. Adaptation has a crucial role in the gradient-sensing mechanism that underlies chemotaxis. The genome sequence of C. jejuni reveals the presence of genes encoding putative adaptation proteins, CheB and CheR. In-frame deletions of cheB, cheR and cheBR were constructed and the chemosensory behaviour of the resultant mutants was examined on swarm plates. CheB and CheR proteins significantly influence chemotaxis but are not essential for this behaviour to occur. Increased mobility of two methyl-accepting chemotaxis proteins (MCPs), DocC and Tlp1, during SDS-PAGE was detected in the mutants lacking functional CheB in the presence of CheR, presumably resulting from stable methylation of receptors. In vitro studies using tissue culture revealed that deletion of cheR resulted in hyperadherent and hyperinvasive phenotypes, while deletion of cheB resulted in nonadherent, noninvasive phenotypes. Furthermore, the ΔcheBR mutant showed significantly reduced ability to colonize chick caeca. Our data suggest that modification of chemoreceptors by the CheBR system is involved in regulation of chemotaxis in C. jejuni although CheB is apparently not controlled by phosphorylation.


Assuntos
Proteínas de Bactérias/metabolismo , Campylobacter jejuni/fisiologia , Fatores Quimiotáticos/metabolismo , Quimiotaxia , Metiltransferases/metabolismo , Animais , Proteínas de Bactérias/genética , Infecções por Campylobacter/microbiologia , Campylobacter jejuni/enzimologia , Campylobacter jejuni/genética , Fatores Quimiotáticos/genética , Galinhas , Regulação Bacteriana da Expressão Gênica , Humanos , Metiltransferases/genética
17.
J Vet Med Sci ; 73(3): 389-91, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21041987

RESUMO

Campylobacter jejuni reportedly exhibits chemotactic behavior towards fucose, several amino acids and organic acids, mucin and bile. The chemotaxis of C. jejuni has mainly been studied using the chemical-in-plug chemotaxis assay. In this study, a nonchemotactic mutant (cheY mutant) and nonmotile mutant (flhA mutant) were constructed and used as negative controls in an assay. Apparent zones of accumulation around test plugs containing several amino acids and organic acids were observed with both of the mutants. Our results suggest that positive responses of C. jejuni in the chemical-in-plug assay are not always indicative of chemotaxis.


Assuntos
Bioensaio/veterinária , Campylobacter jejuni/isolamento & purificação , Quimiotaxia/fisiologia , Técnicas Bacteriológicas , Reações Falso-Positivas
18.
Vet Med Int ; 2021: 6646846, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33747429

RESUMO

We surveyed Staphylococcus aureus contamination in 110 pork samples from 12 fresh meat markets in Nongchok district, Bangkok, Thailand, and performed antimicrobial susceptibility testing with the disk diffusion method. The prevalence of S. aureus was 28.18%, and 52 strains were isolated. Antimicrobial susceptibility testing using the disk diffusion method revealed that 80.77% of the isolates were resistant to tetracycline and 76.92% to ampicillin. All strains were 100% susceptible to cloxacillin, cefoxitin, gentamicin, and cefazolin. The high percentage of antibiotic resistance to tetracycline and ampicillin was attributed to their use in treating infections in farmed animals and their addition to animal food for disease prevention. Interestingly, the present study revealed the intermediate resistance of S. aureus (13.46% of S. aureus-positive pork samples) to vancomycin which is a common medicine for treating severe infection in humans, suggesting that the trend of resistance might increase and becoming a serious problem of public health for both humans and animals.

19.
J Vet Med Sci ; 83(8): 1182-1190, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34108307

RESUMO

Rhodococcus equi is a Gram-positive facultative intracellular bacterium that causes pyogranulomatous pneumonia in foals and immunocompromised people. In the present study, signature-tagged transposon mutagenesis was applied for the negative selection of R. equi mutants that cannot survive in vivo. Twenty-five distinguishable plasmid-transposon (plasposon) vectors by polymerase chain reaction (PCR), each containing a unique oligonucleotide tag, were constructed and used to select the transposon mutants that have in vivo fitness defects using a mouse systemic infection model. Of the 4,560 transposon mutants, 102 mutants were isolated via a real-time PCR-based screening as the mutants were unable to survive in the mouse model. Finally, 50 single transposon insertion sites were determined via the self-cloning strategy. The insertion of the transposon was seen on the virulence plasmid in 15 of the 50 mutants, whereas the remaining 35 mutants had the insertion of transposon on the chromosome. The chromosomal mutants contained transposon insertions in genes involved in cellular metabolism, DNA repair and recombination, gene regulation, non-ribosomal peptide synthesis, and unknown functions. Additionally, seven of the chromosomal mutants showed a reduced ability to multiply in the macrophages in vitro. In this study, we have identified several biosynthetic pathways as fitness factors associated with the growth within macrophages and survival in mice.


Assuntos
Rhodococcus equi , Rhodococcus , Animais , Elementos de DNA Transponíveis/genética , Cavalos , Mutagênese , Plasmídeos/genética , Rhodococcus equi/genética , Virulência/genética
20.
Microbiol Resour Announc ; 10(10)2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33707339

RESUMO

The complete genome sequences of two Staphylococcus argenteus strains, Tokyo13064 and Tokyo13069, isolated from human feces and suspected causative foods during a staphylococcal food poisoning outbreak, consist of 2,750,811-bp and 2,751,556-bp circular chromosomes and 2,543 and 2,548 genome annotation-predicted coding DNA sequences, respectively, with 19 rRNAs, 61 tRNAs, and 1 CRISPR each.

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