Clinical and pathological findings of Rhodococcus equi infection in foals / Achados clínicos e patológicos da infecção por Rhodococcus equi em potros

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.(AU)

Infecção por Rhodococcus equi é considerado um dos maiores problemas sanitários para potros em todo o mundo. Para melhor compreender a apresentação clínica e patológica da enfermidade, foram avaliados vinte casos de infecção natural por R. equi em potros. Os casos são caracterizados de acordo com seus achados clínicos e patológicos e aspectos imuno-histoquímicos. Foram realizados exames de necropsia, histologia, bacteriologia e imuno-histoquímica para R. equi e Pneumocystis spp. Os potros tinham idade media de 60 dias e apresentaram sinais respiratórios (11/20), hipertermia (10/20), aumento de volume articular (6/20), prostração (4/20), distúrbios locomotores (3/20) e diarreia (3/20), entre outros. As lesões mais importantes eram pneumonia piogranulomatosa, vista em 19 potros, acompanhada ou não por linfadenite piogranulomatosa (10/20) e enterocolite ulcerativa (5/20). Osteomielite piogranulomatosa foi constatada em três potros, um dos quais não apresentava envolvimento pulmonar. Artrites afetando uma ou múltiplas articulações eram caracterizadas por infiltrado linfoplasmocítico (4/20), linfoplasmocítico e neutrofílico (1/20) e piogranulomatoso (1/20). A imuno-histoquímica demonstrou ser uma ferramenta valiosa na detecção de R. equi, permitindo confirmar o diagnóstico em todos os casos avaliados. Além disso, a imuno-histoquímica para Pneumocystis spp. demonstra que a coinfecção por R. equi e o agente fúngico é um evento frequente em potros, constatado em 13 casos.(AU)

Clinical and pathological findings of Rhodococcus equi infection in foals / Achados clínicos e patológicos da infecção por Rhodococcus equi em potros

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.(AU)

Infecção por Rhodococcus equi é considerado um dos maiores problemas sanitários para potros em todo o mundo. Para melhor compreender a apresentação clínica e patológica da enfermidade, foram avaliados vinte casos de infecção natural por R. equi em potros. Os casos são caracterizados de acordo com seus achados clínicos e patológicos e aspectos imuno-histoquímicos. Foram realizados exames de necropsia, histologia, bacteriologia e imuno-histoquímica para R. equi e Pneumocystis spp. Os potros tinham idade media de 60 dias e apresentaram sinais respiratórios (11/20), hipertermia (10/20), aumento de volume articular (6/20), prostração (4/20), distúrbios locomotores (3/20) e diarreia (3/20), entre outros. As lesões mais importantes eram pneumonia piogranulomatosa, vista em 19 potros, acompanhada ou não por linfadenite piogranulomatosa (10/20) e enterocolite ulcerativa (5/20). Osteomielite piogranulomatosa foi constatada em três potros, um dos quais não apresentava envolvimento pulmonar. Artrites afetando uma ou múltiplas articulações eram caracterizadas por infiltrado linfoplasmocítico (4/20), linfoplasmocítico e neutrofílico (1/20) e piogranulomatoso (1/20). A imuno-histoquímica demonstrou ser uma ferramenta valiosa na detecção de R. equi, permitindo confirmar o diagnóstico em todos os casos avaliados. Além disso, a imuno-histoquímica para Pneumocystis spp. demonstra que a coinfecção por R. equi e o agente fúngico é um evento frequente em potros, constatado em 13 casos.(AU)

Clinical and pathological findings of Rhodococcus equi infection in foals

ABSTRACT: Infection by Rhodococcus equi is considered one of the major health concerns for foals worldwide. In order to better understand the diseases 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.

RESUMO: Infecção por Rhodococcus equi é considerado um dos maiores problemas sanitários para potros em todo o mundo. Para melhor compreender a apresentação clínica e patológica da enfermidade, foram avaliados vinte casos de infecção natural por R. equi em potros. Os casos são caracterizados de acordo com seus achados clínicos e patológicos e aspectos imuno-histoquímicos. Foram realizados exames de necropsia, histologia, bacteriologia e imuno-histoquímica para R. equi e Pneumocystis spp. Os potros tinham idade media de 60 dias e apresentaram sinais respiratórios (11/20), hipertermia (10/20), aumento de volume articular (6/20), prostração (4/20), distúrbios locomotores (3/20) e diarreia (3/20), entre outros. As lesões mais importantes eram pneumonia piogranulomatosa, vista em 19 potros, acompanhada ou não por linfadenite piogranulomatosa (10/20) e enterocolite ulcerativa (5/20). Osteomielite piogranulomatosa foi constatada em três potros, um dos quais não apresentava envolvimento pulmonar. Artrites afetando uma ou múltiplas articulações eram caracterizadas por infiltrado linfoplasmocítico (4/20), linfoplasmocítico e neutrofílico (1/20) e piogranulomatoso (1/20). A imuno-histoquímica demonstrou ser uma ferramenta valiosa na detecção de R. equi, permitindo confirmar o diagnóstico em todos os casos avaliados. Além disso, a imuno-histoquímica para Pneumocystis spp. demonstra que a coinfecção por R. equi e o agente fúngico é um evento frequente em potros, constatado em 13 casos.

Identification of Mycobacterium species and Rhodococcus equi in peccary lymph nodes.

Mycobacterium species and the virulence-associated proteins (vapA, vapB, and vapN genes) of Rhodococcus equi isolated from 330 lymph nodes of collared peccaries (Tayassu tajacu) and white-lipped peccaries (Tayassu pecari) intended for human consumption were investigated. Thirty-six (10.9%) R. equi strains were isolated; 3.3% (n = 11/330) were from white-lipped peccary lymph nodes, and 7.6% (25/330) were from collared peccary lymph nodes. Among the 11 isolates of R. equi from the white-lipped peccaries, 90.9% (n = 10/11) were obtained from the mesenteric lymph nodes, and only 9.1% (n = 1/10) were obtained from the mediastinal lymph nodes. In the 25 isolates of R. equi obtained from the collared peccaries, 40.0% (n = 10/25) were recovered from the mesenteric lymph nodes, 36% (n = 9/25) from the submandibular lymph nodes, and 24.0% (n = 6/25) from the mediastinal lymph nodes. No vapA, vapB, or vapN genes (plasmidless) or three host-associated types (pVAPA, pVAPB, and pVAPN) were identified among the R. equi isolates. Mycobacterium species were isolated in 3.03% (n = 10/330) of all the lymph nodes analyzed. Among the 10 mycobacterial isolates, 60% (n = 6/10) were from the white-lipped peccary lymph nodes, and 40% (n = 4/10) were from the collared peccary lymph nodes. Ten Mycobacterium species were detected by PCR-PRA with a predominance of M. avium type 1. Sequencing of the hsp65 and rpob genes revealed mycobacteria that were saprophytic (M. sinense and M. kumamotonense) and potentially pathogenic (M. colombiense and M. intracellulare) to humans and animals. To our knowledge, this is the first description of R. equi and/or mycobacterial species identified in the lymph nodes of peccary specimens. R. equi (plasmidless) and the mycobacterial species described here have been reported as causes of pulmonary and extrapulmonary infections in both immunocompetent and immunocompromised humans.

Novel bovine-associated pVAPN plasmid type in Rhodococcus equi identified from lymph nodes of slaughtered cattle and lungs of people living with HIV/AIDS.

Rhodococcus equi is a well-recognized Gram-positive intracellular facultative bacterium that is opportunistic in nature, which causes pyogranulomatous infections in humans and multiple host animals. The pathogenicity of the microorganism 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, and a recently described linear pVAPN plasmid associated with bovine strains, although these three types are found in human isolates. Recent phylogenomic studies support the evidence that human R. equi infection is zoonotically acquired. Nevertheless, data regarding distribution and prevalence of the host-adapted virulence plasmid types of R. equi isolated from meat animals are scarce or unnoticed. Here, the three host-associated virulence plasmid types (pVAPA, pVAPB, and pVAPN) were investigated in 154 R. equi isolates recovered from lymph nodes of cattle with lymphadenitis (n = 31), faeces of cattle without enteric signs (n = 49), as well as different clinical specimens from human patients (n = 74). The analysis of virulence profile of 74 R. equi from humans revealed six (8.1%) isolates pVAPB (type 8), two (2.7%) pVAPN, and one (1.3%) pVAPB (type 11), all of which were from lung samples from people living with HIV/AIDS. From the lymph node samples of cattle, 41.9% (13 of 31) isolates revealed pVAPN type, whereas all isolates from faecal samples were negative for three host-associated types. Here, recently described bovine-associated pVAPN type was detected in R. equi isolates recovered from the lungs of people living with HIV/AIDS and lymph nodes from slaughtered cattle intended for human consumption; a finding that represents a public health concern, mainly in countries where undercooked or raw meat are traditionally consumed.

Susceptibility profile of Brazilian Rhodococcus equi isolates against azithromycin, clarithromycin and erythromycin / Perfil de susceptibilidade de isolados brasileiros de Rhodococcus equi frente à azitromicina, claritromicina e eritromicina

Rhodococcus equi infection treatment is usually a macrolide (azithromycin - AZM, clarithromycin - CLR and erythromycin - ERY) and rifampicin combination. However, resistance cases have been reported, especially for ERY. In view of the need of a study about Brazilian isolates susceptibility profile, this study aimed to characterize the minimum inhibitory concentration (MIC) of the macrolides - AZM, CLR and ERY - against 44 R. equi isolates. It was found all isolates CLR and AZM sensitive; however, for ERY, 27% (12/44) were classified as intermediate sensitivity. R. equi Brazilian isolates used here showed a large susceptibility profile, except against ERY, for which it was observed some resistance evidence. In order to avoid failures in the equine rhodococcosis therapy it was highlighted the importance of microbiological culture and antimicrobial susceptibility testing in vitro before beginning treatment.

No tratamento de infecções por R. equi, usualmente emprega-se uma combinação de macrolídeos (azitromicina - AZI, claritromicina - CLARI e eritromicina - ERI) e rifampicina. Todavia, casos de resistência frente a esses antimicrobianos vêm sendo reportados, especialmente à ERI. Tendo em vista a necessidade de um estudo sobre o perfil de susceptibilidade de isolados brasileiros, buscou-se verificar a concentração inibitória mínima (CIM) de AZI, CLARI e ERI frente a 44 isolados de R. equi de diferentes origens. Todos os isolados analisados demonstraram perfil de sensibilidade à AZI e CLARI; em contraste, frente à ERI, 27% (12/44) apresentaram sensibilidade intermediária. A fim de evitar falhas no tratamento da rodococcse equina, destaca-se a importância da cultura microbiológica e a realização de testes in vitro de susceptibilidade antimicrobiana de R .equi antes do início do tratamento.

Susceptibility profile of Brazilian Rhodococcus equi isolates against azithromycin, clarithromycin and erythromycin / Perfil de susceptibilidade de isolados brasileiros de Rhodococcus equi frente à azitromicina, claritromicina e eritromicina

Rhodococcus equi infection treatment is usually a macrolide (azithromycin - AZM, clarithromycin - CLR and erythromycin - ERY) and rifampicin combination. However, resistance cases have been reported, especially for ERY. In view of the need of a study about Brazilian isolates susceptibility profile, this study aimed to characterize the minimum inhibitory concentration (MIC) of the macrolides - AZM, CLR and ERY - against 44 R. equi isolates. It was found all isolates CLR and AZM sensitive; however, for ERY, 27% (12/44) were classified as intermediate sensitivity. R. equi Brazilian isolates used here showed a large susceptibility profile, except against ERY, for which it was observed some resistance evidence. In order to avoid failures in the equine rhodococcosis therapy it was highlighted the importance of microbiological culture and antimicrobial susceptibility testing in vitro before beginning treatment.(AU)

No tratamento de infecções por R. equi, usualmente emprega-se uma combinação de macrolídeos (azitromicina - AZI, claritromicina - CLARI e eritromicina - ERI) e rifampicina. Todavia, casos de resistência frente a esses antimicrobianos vêm sendo reportados, especialmente à ERI. Tendo em vista a necessidade de um estudo sobre o perfil de susceptibilidade de isolados brasileiros, buscou-se verificar a concentração inibitória mínima (CIM) de AZI, CLARI e ERI frente a 44 isolados de R. equi de diferentes origens. Todos os isolados analisados demonstraram perfil de sensibilidade à AZI e CLARI; em contraste, frente à ERI, 27% (12/44) apresentaram sensibilidade intermediária. A fim de evitar falhas no tratamento da rodococcse equina, destaca-se a importância da cultura microbiológica e a realização de testes in vitro de susceptibilidade antimicrobiana de R .equi antes do início do tratamento.(AU)