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GAPDH, rhbC, and vapA gene expression in Rhodococcus equi cultured under different iron concentrations. Microb Pathog 2019; 139:103885. [PMID: 31790793 DOI: 10.1016/j.micpath.2019.103885] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/07/2019] [Accepted: 11/21/2019] [Indexed: 11/22/2022]
Abstract
The ability of Rhodococcus equi to survive in macrophages and cause pneumonia in foals depends on vapA and rhbC genes, which produce the virulence-associated protein A (VapA) and the rhequichelin siderophore, respectively. Virulent R. equi acquires Fe from transferrin by unknown mechanisms. Our objectives were to determine the role of GAPDH in Fe homeostasis, to further characterize GAPDH, rhbC, and vapA expression under iron homeostasis, and to document the occurrence of rhbC gene in R. equi isolates. Therefore, vapA + R. equi was cultured under excessive, physiologic, and restricted iron concentrations, and quantitative culture and gene expression were performed. The relative expression of GAPDH, rhbC, and vapA after 48 h of culture were analyzed by qPCR. To determine the rhbC occurrence, total DNA was extracted from R. equi isolated from foals with clinical rhodococcosis (n = 22), healthy horses (feces, n = 16; nasal swab, n = 9), soil (n = 6), and 2 ATCC reference strains. Conventional PCR was performed to identify genus/species, vapA, and rhbC genes. Iron restriction proportionally decreased R. equi growth rates, and induced high expression of both GAPDH and vapA. The putative role of GAPDH in R. equi iron homeostasis should be further investigated. rhbC was significantly up-regulated under both Fe excess and critical starvation. The rhbC gene was identified in all clinical isolates and soil, but it was absent in 2 isolates from healthy horses, suggesting that rhequichelin is not required for R. equi nasal and intestinal colonization.
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Oliveira LG, Watanabe TT, Boabaid FM, Wouters F, Wouters AT, Bandarra PM, Guerra PR, Driemeier D. Clinical and pathological findings of Rhodococcus equi infection in foals. PESQUISA VETERINARIA BRASILEIRA 2019. [DOI: 10.1590/1678-5150-pvb-6252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ABSTRACT: Infection by Rhodococcus equi is considered one of the major health concerns for foals worldwide. In order to better understand the disease’s clinical and pathological features, we studied twenty cases of natural infection by R. equi in foals. These cases are characterized according to their clinical and pathological findings and immunohistochemical aspects. Necropsy, histologic examination, bacterial culture, R. equi and Pneumocystis spp. immunohistochemistry were performed. The foals had a mean age of 60 days and presented respiratory signs (11/20), hyperthermia (10/20), articular swelling (6/20), prostration (4/20), locomotor impairment (3/20) and diarrhea (3/20), among others. The main lesions were of pyogranulomatous pneumonia, seen in 19 foals, accompanied or not by pyogranulomatous lymphadenitis (10/20) and pyogranulomatous and ulcerative enterocolitis (5/20). Pyogranulomatous osteomyelitis was seen in 3 foals, one of which did not have pulmonary involvement. There was lymphoplasmacytic (4/20), lymphoplasmacytic and neutrophilic (1/20) or pyogranulomatous arthritis (1/20), affecting multiple or singular joints. Immunohistochemistry revealed to be a valuable tool for the detection of R. equi, confirming the diagnosis in all cases. Furthermore, pulmonary immunostaining for Pneumocystis spp. demonstrates that a coinfection with R. equi and this fungal agent is a common event in foals, seen in 13 cases.
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Gressler LT, Machado G, da Silveira BP, Cohen ND, Corbellini LG, Leotti VB, Diehl GN, Dos Santos LC, de Vargas AC. Prevalence of Rhodococcus equi from the nasal cavity of 1010 apparently healthy horses. Equine Vet J 2018; 50:667-671. [PMID: 29341220 DOI: 10.1111/evj.12804] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 01/09/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Rhodococcus equi is an important cause of foal pneumonia. While its isolation from different sources has been widely evaluated, there is a need to better understand the R. equi epidemiology from samples of the nasal cavity of healthy horses. OBJECTIVES To determine the prevalence of R. equi from the nasal cavity of healthy horses, along with its virulence profile, antimicrobial susceptibility and environmental variables associated. STUDY DESIGN Cross-sectional study. METHODS Swabs from the nasal cavity of 1010 apparently healthy horses from 341 farms were submitted for bacteriological analyses. The identity and virulence profile of the R. equi isolates were assessed by multiplex PCR; antimicrobial susceptibility was determined by the disk-diffusion method. The occurrence of R. equi was calculated at the level of both animal and farm. The association of seven specific environmental factors with R. equi isolation was assessed using logistic regression and by a spatial scan statistical method to determine the presence of local clusters. RESULTS Antimicrobial-sensitive R. equi was isolated from 10 (1%) of 1010 horses ranging between 3 and 29 years old. Ten farms (3%) had at least one positive horse. Only one R. equi isolate (10%) was classified as virulent. Red-Yellow Argisol (PVA/PV) soils were significantly associated with R. equi isolation (odds ratio (OR) 8.02; CI95% , 1.98-32.50, P = 0.01), and areas with well-drained soil were less likely to be test positive (OR 0.85; CI95% , 0.76-0.96, P = 0.03). MAIN LIMITATIONS The use of culture-based method instead of PCR-based assay and the lack of soil sampling. CONCLUSIONS Antimicrobial-sensitive R. equi may be considered a minor part of the normal bacterial flora in the nasal cavity of healthy and immunologically functional horses breeding on pasture. Further studies are warranted to determine if soils rich in iron and well-drained are, in fact, associated with the occurrence of R. equi.
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Affiliation(s)
- L T Gressler
- Laboratory of Bacteriology, Federal University of Santa Maria (UFSM), Cidade Universitária, Bairro Camobi, Santa Maria - Rio Grande do Sul, Brazil
| | - G Machado
- Department of Population Health and Pathobiology, College of Veterinary Medicine North, Carolina State University, Raleigh, North Carolina, USA
| | - B P da Silveira
- Laboratory of Bacteriology, Federal University of Santa Maria (UFSM), Cidade Universitária, Bairro Camobi, Santa Maria - Rio Grande do Sul, Brazil
| | - N D Cohen
- College of Veterinary Medicine, Veterinary Large Animal Clinical Sciences, Texas A&M, College Station, Texas, USA
| | - L G Corbellini
- Department of Statistics, Institute of Mathematics and Statistics and Post-Graduate Program of Epidemiology, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - V B Leotti
- Department of Statistics, Institute of Mathematics and Statistics and Post-Graduate Program of Epidemiology, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - G N Diehl
- Department of Agriculture, Livestock and Agribusiness of the State of Rio Grande do Sul (SEAPA-RS), Brazil, Porto Alegre, Rio Grande do Sul, Brazil
| | - L C Dos Santos
- Department of Agriculture, Livestock and Agribusiness of the State of Rio Grande do Sul (SEAPA-RS), Brazil, Porto Alegre, Rio Grande do Sul, Brazil
| | - A C de Vargas
- Laboratory of Bacteriology, Federal University of Santa Maria (UFSM), Cidade Universitária, Bairro Camobi, Santa Maria - Rio Grande do Sul, Brazil
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Monitoring Foals by Thoracic Ultrasonography, Bacterial Culture, and PCR: Diagnostic of Rhodococcus equi Subclinical Pneumonia in South of Brazil. J Equine Vet Sci 2018. [DOI: 10.1016/j.jevs.2017.08.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Trevisani MM, Hanna ES, Oliveira AF, Cardoso SA, Roque-Barreira MC, Soares SG. Vaccination of Mice with Virulence-Associated Protein G (VapG) Antigen Confers Partial Protection against Rhodococcus equi Infection through Induced Humoral Immunity. Front Microbiol 2017; 8:857. [PMID: 28553279 PMCID: PMC5425581 DOI: 10.3389/fmicb.2017.00857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 04/27/2017] [Indexed: 11/13/2022] Open
Abstract
Rhodococcus equi is a facultative intracellular bacterium causing severe pyogranulomatous pneumonia, ulcerative enterocolitis, and mesenteric lymphadenopathy in foals aged less than 6 months. Less frequently, this pathogen affects various other species, such as pigs, cattle, cats, and even humans. Although rhodococcosis is treated with a combination of antimicrobial agents, resistance is developed in some cases, and thus, antimicrobial susceptibility must be monitored and managed. Considering these limitations of the current therapy and unavailability of a vaccine to prevent the disease, research is particularly focused on the development of an effective vaccine against rhodococcosis. Most vaccines undergoing development utilize the virulence-associated protein (Vap) A antigen, which was identified previously as a key virulence factor of R. equi. Nevertheless, other proteins, such as VapG, present in most virulent R. equi strains, are also encoded by vap genes located on the R. equi bacterial virulence plasmid. In the present study, we evaluated the effect of VapG immunization on the survival of R. equi-challenged mice. We used attenuated Salmonella as a carrier for VapG (Salmonella-vapG+), a procedure previously adopted to develop a VapA-based vaccine. We observed that vaccination with Salmonella-vapG+ induced both an increased IFN-γ, IL-12, and TNF-α production, and a decreased bacterial burden in organs of the R. equi-challenged mice. Nevertheless, Salmonella-vapG+ vaccination protected only 50% of the mice challenged with a lethal dose of R. equi. Interestingly, we observed an increased frequency of B cells in the spleen of Salmonella-vapG+-vaccinated mice and showed that Salmonella-vapG+-vaccinated R. equi-challenged B-cell-knockout mice did not reduce the bacterial burden. Given these results, we discussed the potential role of the humoral immune response induced by Salmonella-vapG+ vaccination in conferring protection against R. equi infection, as well as the employment of VapG antigen for obtaining hyperimmune plasma to prevent rhodoccocosis in young foals.
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Affiliation(s)
- Marcel M Trevisani
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Ebert S Hanna
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Aline F Oliveira
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Silvia A Cardoso
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Maria C Roque-Barreira
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Sandro G Soares
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
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Madrigal RG, Shaw SD, Witkowski LA, Sisson BE, Blodgett GP, Chaffin MK, Cohen ND. Use of Serial Quantitative PCR of the vapA Gene of Rhodococcus equi in Feces for Early Detection of R. equi Pneumonia in Foals. J Vet Intern Med 2016; 30:664-70. [PMID: 26806422 PMCID: PMC4913589 DOI: 10.1111/jvim.13828] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/13/2015] [Accepted: 12/16/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Current screening tests for Rhodococcus equi pneumonia in foals lack adequate accuracy for clinical use. Real-time, quantitative PCR (qPCR) for virulent R. equi in feces has not been systematically evaluated as a screening test. OBJECTIVE The objective of this study was to evaluate the accuracy of qPCR for vapA in serially collected fecal samples as a screening test for R. equi pneumonia in foals. ANIMALS One hundred and twenty-five foals born in 2011 at a ranch in Texas. METHODS Fecal samples were collected concurrently with thoracic ultrasonography (TUS) screening examinations at ages 3, 5, and 7 weeks. Affected (pneumonic) foals (n = 25) were matched by age and date-of-birth to unaffected (n = 25) and subclinical (ie, having thoracic TUS lesions but no clinical signs of pneumonia) foals (n = 75). DNA was extracted from feces using commercial kits and concentration of virulent R. equi in feces was determined by qPCR. RESULTS Subsequently affected foals had significantly greater concentrations of vapA in feces than foals that did not develop pneumonia (unaffected and subclinical foals) at 5 and 7 weeks of age. Accuracy of fecal qPCR, however, was poor as a screening test to differentiate foals that would develop clinical signs of pneumonia from those that would remain free of clinical signs (including foals with subclinical pulmonary lesions attributed to R. equi) using receiver operating characteristic (ROC) methods. CONCLUSIONS AND CLINICAL IMPORTANCE In the population studied, serial qPCR on feces lacked adequate accuracy as a screening test for clinical R. equi foal pneumonia.
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Affiliation(s)
- R G Madrigal
- Department of Large Animal Clinical Sciences, College of Biomedical Sciences and Veterinary Medicine, Texas A&M University, College Station, TX
| | - S D Shaw
- Department of Large Animal Clinical Sciences, College of Biomedical Sciences and Veterinary Medicine, Texas A&M University, College Station, TX
| | - L A Witkowski
- Laboratory of Veterinary Epidemiology and Economics, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland
| | - B E Sisson
- Department of Large Animal Clinical Sciences, College of Biomedical Sciences and Veterinary Medicine, Texas A&M University, College Station, TX
| | | | - M K Chaffin
- Department of Large Animal Clinical Sciences, College of Biomedical Sciences and Veterinary Medicine, Texas A&M University, College Station, TX
| | - N D Cohen
- Department of Large Animal Clinical Sciences, College of Biomedical Sciences and Veterinary Medicine, Texas A&M University, College Station, TX
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Shaw SD, Cohen ND, Chaffin MK, Blodgett GP, Syndergaard M, Hurych D. Estimating the Sensitivity and Specificity of Real-Time Quantitative PCR of Fecal Samples for Diagnosis of Rhodococcus equi Pneumonia in Foals. J Vet Intern Med 2015; 29:1712-7. [PMID: 26436545 PMCID: PMC4895660 DOI: 10.1111/jvim.13631] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 07/17/2015] [Accepted: 08/26/2015] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Real-time, quantitative PCR (qPCR) methods for detecting Rhodococcus equi in feces have been developed as a noninvasive, rapid diagnostic test for R. equi pneumonia, but have not been evaluated in a large population of foals. OBJECTIVE The objective of this study was to evaluate the clinical utility of fecal PCR as a diagnostic test for R. equi pneumonia in foals using receiver operating characteristic (ROC) methods. ANIMALS 186 foals born in 2011 at an R. equi-endemic ranch in Texas. METHODS Fecal samples were collected at the time of onset of clinical signs for pneumonic foals (n = 31). Foals with pneumonia were matched by age and birth date to healthy (n = 31) and subclinical (n = 124) control foals; fecal samples were collected from these controls. DNA was extracted from feces using commercial kits and concentration of virulent R. equi in feces was determined by qPCR. RESULTS Concentration of R. equi in feces differed significantly (P < .05) among groups. The area under the ROC curve for fecal qPCR for diagnosis of R. equi pneumonia was 89% (95% CI, 83-99), with a sensitivity of 94% and specificity of 72%. CONCLUSIONS AND CLINICAL IMPORTANCE qPCR of feces can be useful as an alternative to tracheobronchial aspiration for the diagnosis of R. equi in foals with clinical signs of pneumonia. Caution should be used in extrapolating results of this study to other populations because fecal concentration of R. equi might vary by geographic location or management practices.
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Affiliation(s)
- S D Shaw
- Department of Large Animal Clinical Sciences, College of Biomedical Sciences and Veterinary Medicine, Texas A&M University, College Station, TX
| | - N D Cohen
- Department of Large Animal Clinical Sciences, College of Biomedical Sciences and Veterinary Medicine, Texas A&M University, College Station, TX
| | - M K Chaffin
- Department of Large Animal Clinical Sciences, College of Biomedical Sciences and Veterinary Medicine, Texas A&M University, College Station, TX
| | | | | | - D Hurych
- Department of Large Animal Clinical Sciences, College of Biomedical Sciences and Veterinary Medicine, Texas A&M University, College Station, TX
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Gressler LT, Vargas ACD, Costa MMD, Sutili FJ, Schwab M, Pereira DIB, Sangioni LA, Botton SDA. Biofilm formation by Rhodococcus equi and putative association with macrolide resistance. PESQUISA VETERINARIA BRASILEIRA 2015. [DOI: 10.1590/s0100-736x2015001000003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abstract: Rhodococcus equi is a facultative intracellular pathogen, which cause severe pyogranulomatous pneumonia in foals and tuberculosis-like lesions in humans. Its ability to form biofilm was described in strains isolated from chronic diseases associated to treatment failures in humans. This study aimed to verify the biofilm formation by 113 R. equi isolated from equine samples (clinical and fecal) using two different methods (biofilm-culturing with and without additional glucose and epifluorescence microscopy). We also aimed to determine the efficacy of azithromycin, clarithromycin and erythromycin on R. equi in established biofilm. We found 80.5% (26/41) and 63% (58/72) biofilm-positive isolates, in fecal and clinical samples, respectively. The additional glucose increased the biofilm formation by R. equi fecal samples, but not by clinical samples. The antimicrobials tested herein were not able to eradicate R. equi in biofilm even at higher concentrations. This is the first study showing the biofilm formation by R. equi isolated from equine samples. Our findings indicate that R. equi biofilm-producers may be more resistant to the antimicrobials evaluated. Further studies are warranted to test this hypothesis.
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Sagave L, Gressler L, Flores F, Silva CB, Vargas A, Lovato M, Sangioni L, Pötter L, Botton S. Atividade de nanoformulações de Melaleuca alternifolia e terpinen-4-ol em isolados de Rhodococcus equi. ARQ BRAS MED VET ZOO 2015. [DOI: 10.1590/1678-7454] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Rhodococcus equi é o agente etiológico da rodococose equina, importante doença respiratória de potros. Especialmente na última década, a emergência de cepas resistentes aos antimicrobianos empregados no tratamento da rodococose tem sido relatada. Nesse sentido, há a necessidade de estudos envolvendo terapias alternativas e novas tecnologias, incluindo o uso de plantas medicinais e nanotecnologia. Neste trabalho utilizou-se Melaleuca alternifolianas seguintes formulações: óleo livre, nanocápsula, nanoemulsão e a combinação de óleo livre com nanocápsula e com nanoemulsão, além do seu composto majoritário, terpinen-4-ol, a fim de verificar a atividade antimicrobiana frente a isolados de R. equide diferentes origens. Utilizou-se o método de microdiluição em caldo na determinação das concentrações inibitória mínima (CIM) e bactericida mínima (CBM) das diferentes formulações frente aos isolados (n=24). Verificou-se baixo potencial para atividade antibacteriana de M. alternifoliana formulação de óleo livre. Todavia, essa atividade foi potencializada quando se incorporou o óleo essencial às nanoformulações. O composto terpinen-4-ol demonstrou potencial atividade antibacteriana quando incorporado ao óleo essencial e quando utilizado isoladamente. Verificou-se que tanto M. alternifolia quanto terpinen-4-ol testados possuem atividade antimicrobiana contra isolados de R. equi, sugerindo seu emprego em estudos avaliando seu potencial para o tratamento da rodococose.
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Gressler LT, de Vargas AC, da Costa MM, Pötter L, da Silveira BP, Sangioni LA, de Avila Botton S. Genotypic and phenotypic detection of efflux pump in Rhodococcus equi. Braz J Microbiol 2014; 45:661-5. [PMID: 25242956 PMCID: PMC4166297 DOI: 10.1590/s1517-83822014000200040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 03/14/2014] [Indexed: 11/22/2022] Open
Abstract
The req_39680 gene, associated to a putative efflux system, was detected in 60% (54/90) of R. equi isolates by PCR. The phenotypic expression of efflux mechanism was verified in 20% of the isolates using ethidium bromide. For the first time, the expression of efflux mechanism was demonstrated in R. equi.
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Affiliation(s)
- Letícia Trevisan Gressler
- Departamento de Medicina Veterinária Preventiva Universidade Federal de Santa Maria Santa MariaRS Brazil Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Agueda Castagna de Vargas
- Departamento de Medicina Veterinária Preventiva Universidade Federal de Santa Maria Santa MariaRS Brazil Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Mateus Matiuzzi da Costa
- Laboratório de Imunologia e Microbiologia Universidade Federal do Vale do São Francisco PetrolinaPE Brazil Laboratório de Imunologia e Microbiologia, Universidade Federal do Vale do São Francisco, Petrolina, PE, Brazil
| | - Luciana Pötter
- Departamento de Zootecnia Universidade Federal de Santa Maria Santa MariaRS Brazil Departamento de Zootecnia, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Bibiana Petri da Silveira
- Departamento de Medicina Veterinária Preventiva Universidade Federal de Santa Maria Santa MariaRS Brazil Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Luis Antônio Sangioni
- Departamento de Medicina Veterinária Preventiva Universidade Federal de Santa Maria Santa MariaRS Brazil Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Sônia de Avila Botton
- Departamento de Medicina Veterinária Preventiva Universidade Federal de Santa Maria Santa MariaRS Brazil Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
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Girardini LK, Gressler LT, Costa MMD, Botton SDA, Pellegrini DDCP, Vargas ACD. Perfil de suscetibilidade antimicrobiana e presença do gene vapA em Rhodococcus equi de origem humana, ambiental e equina. PESQUISA VETERINARIA BRASILEIRA 2013. [DOI: 10.1590/s0100-736x2013000600008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rhodococcus equi é um micro-organismo intracelular facultativo, agente etiológico da rodococose, uma importante enfermidade que acomete principalmente potros com menos de seis meses de idade, causando a morte geralmente em decorrência de lesões pulmonares. Este agente também tem potencial zoonótico e emergiu como um patógeno oportunista no mundo, acometendo humanos imunocomprometidos, especialmente os transplantados e infectados pelo vírus da imunodeficiência humana (HIV). Entretanto, infecções por R. equi em hospedeiros hígidos tem sido relatadas, principalmente em crianças e idosos. Estudos tem mostrado um nível crescente na resistência de isolados de R. equi em relação aos antimicrobianos comumente utilizados no tratamento de animais e seres humanos infectados por este agente. A virulência deste pode estar associada a fatores como a cápsula de polissacarídeo, fosfolipase C e à enzima colesterol oxidase (fator equi). No entanto, uma proteína localizada em um plasmídeo, designada vapA, é essencial para a sobrevivência e replicação do agente em macrófagos. Com isso, os objetivos deste estudo foram avaliar o perfil de suscetibilidade de isolados de R. equi de diferentes fontes em relação aos antimicrobianos mais comumente utilizados na terapêutica animal e humana, bem como verificar a associação entre a presença do gene vapA e o índice de resistência múltipla aos antimicrobianos (IRMA). Neste estudo, 67 isolados brasileiros de R. qui de diferentes fontes foram analisados: 30 provenientes de amostras clínicas de equinos, sete de humanos e 30 ambientais (seis do solo e 24 de fezes de equinos). Para avaliar o perfil de suscetibilidade dos isolados utilizou-se o método de disco difusão, sendo testadas 16 drogas de diferentes classes de antimicrobianos. As amostras clínicas de equinos apresentaram as maiores taxas de resistência à penicilina (86,7%) e lincomicina (30%). Além disso, foram também resistentes a macrolídeos (azitromicina a 6,7%, eritromicina a 6% e claritromicina a 3,3%) e rifamicina (13%). Todas as amostras humanas e ambientais foram sensíveis aos macrolídeos e rifamicina. Contudo, isolados ambientais demonstraram níveis elevados de resistência à penicilina e cloranfenicol. Da mesma forma, os isolados humanos apresentaram alto nível de resistência ao ceftiofur, lincomicina e sulfazotrim. O IRMA em todos os isolados de R. equi variou de 0 a 0,67, tendo como valores médios 0,19 para as amostras clínicas de equinos, 0,14 nas ambientais e em isolados humanos foi de 0,1. Apesar da alta sensibilidade observada nos isolados analisados, verificaram-se diferentes níveis de resistência nas amostras clínicas de equinos. Em contraste, os isolados ambientais não demonstraram resistência em relação aos agentes antimicrobianos utilizados na terapia da rodococose equina. Além disso, em isolados humanos não se observou resistência contra a droga para uso restrito em terapia de humano. Com base no IRMA observado em isolados clínicos de equinos, destacamos a importância de medidas restritivas e mais cautela na utilização de antimicrobianos em infecções causadas por R. equi para evitar o aumento de novas cepas multirresistentes.
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de Vargas AC, Monego F, Gressler LT, de Avila Botton S, Lazzari AM, da Costa MM, Ecco R, Ribeiro MG, Lara GHB, Takai S. Bronchopneumonia in wild boar (Sus scrofa) caused by Rhodococcus equi carrying the VapB type 8 plasmid. BMC Res Notes 2013; 6:111. [PMID: 23531380 PMCID: PMC3630014 DOI: 10.1186/1756-0500-6-111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 03/18/2013] [Indexed: 11/29/2022] Open
Abstract
Background Rhodococcus equi is associated with pyogranulomatous infections, especially in foals, and this bacterium has also emerged as a pathogen for humans, particularly immunocompromised patients. R. equi infections in pigs, wild boar (Sus scrofa) and humans are mainly due to strains carrying the intermediate virulence (VapB) plasmid. In Brazil, R. equi carrying the VapB type 8 plasmid is the most common type recovered from humans co-infected with the human immunodeficiency virus (HIV). R. equi infection in pigs and wild boar is restricted predominantly to the lymphatic system, without any reports of pulmonary manifestations. Findings This report describes the microbiological and histopathological findings, and molecular characterization of R. equi in two bronchopneumonia cases in wild boar using PCR and plasmid profile analysis by digestion with restriction endonucleases. The histological findings were suggestive of pyogranulomatous infection, and the plasmid profile of both R. equi isolates enabled the characterization of the strains as VapB type 8. Conclusions This is the first report of bronchopneumonia in wild boar due to R. equi. The detection of the VapB type 8 plasmid in R. equi isolates emphasize that wild boar may be a potential source of pathogenic R. equi strains for humans.
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Affiliation(s)
- Agueda Castagna de Vargas
- Department of Preventive Veterinary Medicine, Universidade Federal de Santa Maria, UFSM, 97105-900, Santa Maria, State of Rio Grande do Sul, Brazil.
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Yamshchikov AV, Schuetz A, Lyon GM. Rhodococcus equi infection. THE LANCET. INFECTIOUS DISEASES 2010; 10:350-9. [DOI: 10.1016/s1473-3099(10)70068-2] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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