RESUMO
Rhodococcus equi is responsible for infections in multiple-host animals. In humans, the prevalence of rhodococcus has increased worldwide and represents an emergent risk. R. equi is a soil-borne opportunistic bacterium isolated from feces of a wide variety of domestic species, except cats; thus, there is no known potential risk of its transmission from humans. Here, the mono- and cooccurrence of Rhodococcus equi and other bacteria and selected virulence markers were investigated in feces of nondiarrheic cats from urban (n=100) and rural (n=100) areas. Seven (7/200=3.5%) R. equi isolates were recovered in ceftazidime, novobiocin, and cycloheximide (CAZ-NB) selective media, exclusively of cats from three distinct farms (p=0.01), and these cats had a history of contact with horses and their environment (p=0.0002). None of the R. equi isolates harbored hosted-adapted plasmid types associated with virulence (pVAPA, pVAPB, and pVAPN). One hundred seventy-five E. coli isolates were identified, and 23 atypical enteropathogenic E. coli (aEPEC), 1 STEC (Shiga-toxin producing E. coli), and 1 EAEC (enteroaggregative E. coli) were detected. Eighty-six C. perfringens type A isolates were identified, and beta-2 and enterotoxin were detected in 21 and 1 isolates, respectively. Five C. difficile isolates were identified, one of which was toxigenic and ribotype 106. The main cooccurring isolates in cats from urban areas were E. coli and C. perfringens A (26/100=26%), E. coli and C. perfringens type A cpb2+ (8/100=8%), and aEPEC (eae+/escN+) and C. perfringens type A (5/100=5%). In cats from farms, the main cooccurring isolates were E. coli and C. perfringens type A (21/100=21%), E. coli and C. perfringens type A cpb 2 + 8/100=8%), and E. coli and R. equi (4/100=4%). We identified, for the first time, R. equi in nondiarrheic cats, a finding that represents a public health issue because rhodococcus has been reported in both immunosuppressed and immunocompetent humans, particularly people living with HIV/AIDS.
Assuntos
Gatos/microbiologia , Fezes/microbiologia , Rhodococcus equi/isolamento & purificação , Microbiologia do Solo , Animais , Clostridioides difficile/genética , Clostridioides difficile/isolamento & purificação , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Cavalos/microbiologia , Humanos , Rhodococcus equi/genética , Rhodococcus equi/patogenicidadeRESUMO
RESUMEN Rhodococcus equi es un microorganismo emergente asociado a infecciones oportunistas en individuos inmunocomprometidos, especialmente en pacientes con infección por virus de inmunodeficiencia humana. Se desarrolló una búsqueda en la Biblioteca Virtual de Infomed, fueron revisados 215 trabajos científicos sin limitación de año y país, seleccionándose 55. El rhodococcus es un patógeno intracelular capaz de crecer y persistir dentro de los macrófagos que expresan en su superficie el receptor Mac-1 (CD11b/CC18), y posteriormente destruirlos. La manifestación clínica más frecuente es la neumonía de comienzo insidioso y en su evolución natural tiende a la cavitación. El diagnóstico se realiza mediante su identificación en cultivo de muestras de tejido afectado. Los hemocultivos son positivos en el 50% de los inmunodeprimidos En el diagnóstico radiográfico, los hallazgos más comunes referidos en la literatura científica son el compromiso lobar y la cavitación. La particular evolución que experimentan los pacientes con síndrome de inmunodeficiencia adquirida y neumonía por R. equi, obliga a implementar esquemas terapéuticos basados en antimicrobianos con actividad bactericida intracelular, administrados inicialmente por vía intravenosa y durante un tiempo prolongado e incluso la cirugía. La infección por R. equi es una complicación infrecuente en pacientes con síndrome de inmunodeficiencia adquirida, pero con una elevada tasa de letalidad, por lo que debe ser sospechado en pacientes que presenten una infección respiratoria de curso inhabitual. El diagnóstico precoz, el tratamiento antimicrobiano combinado y prolongado y el inicio de la Terapia Antiretroviral de Gran Actividad en forma temprana pueden mejorar la evolución y el pronóstico de estos pacientes.
ABSTRACT Rhodococcus equi is an emergent microorganism associated to opportunistic infections in immune-compromised individuals, especially in patients infected with the human immunodeficiency virus. A search was carried out in the Virtual Library of Infomed; 215 scientific works were reviewed without limits of publication years and countries. From them, 55 were chosen. Rhodococcus equi is an intracellular pathogen that is able to grow and live inside the macrophages expressing the Mac-1 (CD11b/CC18) receptor in the surface and destroying them later. The most common clinical manifestation is insidious beginning pneumonia, tending to cavitation in its natural evolution. The diagnosis is made through identification in culture of affected tissues samples. Blood cultures are positive in 50 % of the immune-depressed people. At the radiographic diagnosis, the most common findings referred to in the scientific literature are lobar compromise and cavitation. The particular evolution of the patients with acquired immune-deficiency syndrome and pneumonia due to Rhodococcus equi forces the implementation of therapeutic schemes based on antimicrobials with intracellular bactericide activity, administered firstly intravenously and during a long time, and even to perform the surgery. Rhodococcus equi infection is an infrequent complication in patients with acquired immunodeficiency syndrome, but having a high lethality rate, therefore it should be suspected in patients presenting a respiratory infection of unusual curse. The precocious diagnosis, combined and prolonged antimicrobial treatment and early beginning of the highly active antiretroviral therapy could improve the evolution and prognosis of these patients.
Assuntos
Humanos , Infecções por HIV/complicações , Pneumonia Bacteriana/complicações , Pneumonia Bacteriana/diagnóstico , Pneumonia Bacteriana/tratamento farmacológico , Antirretrovirais/uso terapêutico , Infecções por Actinomycetales/diagnóstico , Rhodococcus equi/patogenicidade , Pneumonia Bacteriana/etiologiaRESUMO
Resumen Rhodococcusequi, bacteria aislada principalmente en potros, se considera en la actualidad un patógeno zoonótico emergente en seres humanos, la mayoría inmunocomprometidos, coincidiendo con la epidemia de VIH y los avances en la medicina de trasplantes y la quimioterapia del cáncer, lo que justifica la revisión sobre su patogenia, características clínicas, diagnóstico y tratamiento. Más frecuente en hombres que en mujeres, el inicio de las infecciones es generalmente insidioso y los síntomas que presentan varían según el sitio de la infección, la enfermedad respiratoria, caracterizada por neumonía necrosante es la manifestación más común, y tiende a seguir un curso subagudo, mientras las personas inmunocompetentes son afectadas con baja frecuencia y suelen presentarse con enfermedad localizada. Las infecciones de la piel o partes blandas, incluyendo abscesos, son poco frecuentes incluso en huéspedes inmunocomprometidos y están usualmente relacionadas con contaminación ambiental. El laboratorio de microbiología juega un papel clave en la identificación del organismo, ya que este puede confundirse con flora normal de la piel. El caso que se presenta corresponde a una paciente adulta inmunocompetente, con infección de herida quirúrgica por R equiluego de una cirugía estética, requirió tratamiento antibiótico, múltiples lavados quirúrgicos y debridamientos, más drenaje de absceso, con mejoría del proceso infeccioso. Este caso sugiere la importancia clínica de la identificación precisa de patógenos inusuales, capaces de entorpecer la evolución normal de un proceso quirúrgico y de producir un alto costo de atención de salud y el alcance medidas preventivas relacionadas con la vigilancia de la salud.
Abstract Rhodococcusequi, a bacterium isolated mainly in foals, is currently considered an emerging zoonotic pathogen in humans, most of them immunocompromised, coinciding with the HIV epidemic and advances in transplant medicine and cancer chemotherapy, which justifies the review on its pathogenesis, clinical characteristics, diagnosis and treatment. More frequent in men than in women, the onset of infections is usually insidious and the symptoms they present vary according to the site of infection, the respiratory disease, characterized by necrotizing pneumonia is the most common manifestation, and tends to follow a subacute course , while immunocompetent people are affected with low frequency and usually have localized disease. Infections of the skin or soft tissues, including abscesses, are rare even in immunocompromised hosts and are usually related to environmental contamination. The microbiology laboratory plays a key role in the identification of the organism, since it can be confused with normal flora of the skin. The case presented corresponds to an adult immunocompetent patient, with surgical wound infection by R equiafter cosmetic surgery, required antibiotic treatment, multiple surgical washes and debridements, and abscess drainage, with improvement of the infectious process. This case suggests the clinical importance of the precise identification of unusual pathogens, capable of obstructing the normal evolution of a surgical process and of producing a high cost of health care and the scope of preventive measures related to health surveillance.
Assuntos
Humanos , Feminino , Adulto , Nádegas/cirurgia , Rhodococcus equi/patogenicidade , Rhodococcus equi/efeitos dos fármacos , Costa RicaRESUMO
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.
Assuntos
Artiodáctilos/microbiologia , Linfonodos/microbiologia , Mycobacterium/isolamento & purificação , Rhodococcus equi/isolamento & purificação , Animais , Humanos , Mycobacterium/genética , Reação em Cadeia da Polimerase , Rhodococcus equi/patogenicidade , VirulênciaRESUMO
Seven genomes of Corynebacterium pseudotuberculosis biovar equi were sequenced on the Ion Torrent PGM platform, generating high-quality scaffolds over 2.35 Mbp. This bacterium is the causative agent of disease known as "pigeon fever" which commonly affects horses worldwide. The pangenome of biovar equi was calculated and two phylogenomic approaches were used to identify clustering patterns within Corynebacterium genus. Furthermore, other comparative analyses were performed including the prediction of genomic islands and prophages, and SNP-based phylogeny. In the phylogenomic tree, C. pseudotuberculosis was divided into two distinct clades, one formed by nitrate non-reducing species (biovar ovis) and another formed by nitrate-reducing species (biovar equi). In the latter group, the strains isolated from California were more related to each other, while the strains CIP 52.97 and 1/06-A formed the outermost clade of the biovar equi. A total of 1,355 core genes were identified, corresponding to 42.5% of the pangenome. This pangenome has one of the smallest core genomes described in the literature, suggesting a high genetic variability of biovar equi of C. pseudotuberculosis. The analysis of the similarity between the resistance islands identified a higher proximity between the strains that caused more severe infectious conditions (infection in the internal organs). Pathogenicity islands were largely conserved between strains. Several genes that modulate the pathogenicity of C. pseudotuberculosis were described including peptidases, recombination enzymes, micoside synthesis enzymes, bacteriocins with antimicrobial activity and several others. Finally, no genotypic differences were observed between the strains that caused the three different types of infection (external abscess formation, infection with abscess formation in the internal organs, and ulcerative lymphangitis). Instead, it was noted that there is a higher phenetic correlation between strains isolated at California compared to the other strains. Additionally, high variability of resistance islands suggests gene acquisition through several events of horizontal gene transfer.
Assuntos
Infecções por Corynebacterium/genética , Corynebacterium pseudotuberculosis/genética , Genoma Bacteriano/genética , Doenças dos Cavalos/genética , Rhodococcus equi/genética , Animais , Infecções por Corynebacterium/microbiologia , Corynebacterium pseudotuberculosis/patogenicidade , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Doenças dos Cavalos/microbiologia , Cavalos/microbiologia , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Rhodococcus equi/patogenicidadeRESUMO
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...
Rhodococcus equi é um patógeno intracelular facultativo, o qual causa pneumonia piogranulosa severa em potros e lesões semelhantes à tuberculose em humanos. A sua capacidade de formar biofilme foi descrita em cepas humanas, isoladas a partir de doenças crônicas associadas a falhas de tratamento. Este estudo teve como objetivo verificar a formação de biofilme por 113 cepas de R. equi, isoladas a partir de amostras de equinos (clínicas e fecais), utilizando-se dois diferentes métodos (biofilme em cultura - com e sem adição de glicose - e microscopia de epifluorescência). Além disso, buscou-se determinar a eficácia da azitromicina, claritromicina e eritromicina sobre biofilme consolidado de R. equi. Verificou-se 80,5% (26/41) e 63% dos isolados (58/72) positivos para formação de biofilme, em amostras fecais e clínicas, respectivamente. A adição de glicose amentou a formação de biofilme em amostras fecais, mas não em amostras clínicas. Os antimicrobianos aqui testados não foram capazes de erradicar R. equi em biofilme consolidado, mesmo em concentrações elevadas. Este é o primeiro estudo a demonstrar a formação de biofilme por cepas de R. equi isoladas a partir de amostras de equinos. Os resultados indicam que os isolados de R. equi produtores de biofilme podem ser mais resistentes aos antimicrobianos avaliados. Estudos adicionais são necessários para testar essa hipótese...
Assuntos
Animais , Biofilmes , Cavalos/microbiologia , Macrolídeos/antagonistas & inibidores , Rhodococcus equi/fisiologia , Rhodococcus equi/patogenicidade , Resistência Microbiana a Medicamentos , Glucose/isolamento & purificaçãoRESUMO
Virulence of Rhodococcus equi strains from 20 humans in Brazil was investigated by using a polymerase chain reaction to characterize isolates as virulent (VapA), intermediately virulent (VapB), and avirulent. Nine isolates were obtained from human immunodeficiency virus (HIV)-positive patients, six from HIV-negative patients, and five from patients of unknown status. Five isolates were VapB positive, four were VapA positive, and eleven were avirulent. Among the nine isolates from HIV-positive patients, five contained VapB plasmids and two contained VapA plasmids. Five VapB-positive isolates had the type 8 virulence plasmid. Eleven of the patients had a history of contact with livestock and/or a farm environment, and none had contact with pigs.
Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , Infecções por Actinomycetales/microbiologia , Plasmídeos/metabolismo , Rhodococcus equi/patogenicidade , Síndrome da Imunodeficiência Adquirida/epidemiologia , Infecções por Actinomycetales/epidemiologia , Brasil/epidemiologia , Regulação Bacteriana da Expressão Gênica , Humanos , Plasmídeos/genética , Pneumonia Bacteriana/microbiologia , Rhodococcus equi/genética , VirulênciaRESUMO
The virulence genes and plasmid profiles of 23 Rhodococcus equi isolates from 258 lymph nodes from domestic pigs (129 nodes with lesions and 129 without lesions) and 120 lymph nodes from slaughtered wild boars (60 nodes with lesions and 60 without) were characterized. R. equi was obtained from 19 lymph nodes of domestic pigs, 17 with, and two without lesions, and from four lymph nodes with lesions, from wild boars. The 23 isolates were tested for the presence of vapA and vapB genes, responsible for the 15-17 and 20 kDa virulence-associated proteins, respectively, by PCR in order to characterize as virulent (VapA), intermediately virulent (VapB) and avirulent. Plasmid DNAs were isolated and analyzed by digestion with restriction endonucleases to estimate size and compare their polymorphisms. Of the 19 domestic pigs strains, seven (36.8%) were avirulent and 12 (63.2%) were intermediately virulent, with the intermediately virulent isolates being plasmid types 8 (8 isolates), 10 (2 isolates), 1 (1 isolate) and 29 (1 isolate). The plasmid type of four strains isolated from wild boars was also intermediately virulent type 8. None of the domestic pigs and wild boar isolates showed the vapA gene. These findings demonstrate a high occurrence of plasmid type 8 in isolates from pigs and wild boars, and the similarity of plasmid types in the domestic pigs, wild boars and human isolates in Brazil.
Assuntos
Infecções por Actinomycetales/veterinária , Plasmídeos/genética , Rhodococcus equi/genética , Rhodococcus equi/patogenicidade , Sus scrofa , Doenças dos Suínos/microbiologia , Infecções por Actinomycetales/epidemiologia , Infecções por Actinomycetales/microbiologia , Animais , Brasil/epidemiologia , Suínos , Doenças dos Suínos/epidemiologia , VirulênciaRESUMO
This study evaluated the molecular characteristics of Rhodococcus equi isolates obtained from horses by a multiplex PCR assay that amplifies the vap gene family (vapA, -B, -C, -D, -E, -F, -G, and -H). A total of 180 R. equi isolates were studied from four different sources, namely healthy horse feces (112), soil (12), stalls (23), and clinical isolates (33) from horse-breeding farms. The technique was performed and confirmed by sequencing of amplified vap gene family controls. Thirty-two (17.8%) of the R. equi isolates were positive for the vapA gene and carried at least three other vap genes. All 147 isolates from equine feces, stalls, and soil failed to demonstrate any genes associated with virulence-inducing proteins. About 32 (97.0%) out of the 33 clinical equine isolates tested positive for the multiplex PCR assay for the vap gene family. They demonstrated six molecular profiles: 100% featured the vapA, vapD, and vapG genes, 86.6% vapF, 76.6% vapH, 43.3% vapC, 36.6% vapE, and none vapB. The most frequent molecular profile was vap A, -D, -F, G, and -H, where this profile was present in 37.5% of the strains. Moreover, there was no molecular epidemiological pattern for R. equi isolates that uniquely mapped to each horse-breeding farm studied. Our proposed technique allows the identification of eight members of the vap gene family (vapA, B, -C, -D, -E, -F, -G, and -H). It is a practical and efficient method of conducting clinical and epidemiological studies on R. equi isolates.
Assuntos
Infecções por Actinomycetales/veterinária , Proteínas de Bactérias/genética , Doenças dos Cavalos/microbiologia , Cavalos/microbiologia , Glicoproteínas de Membrana/genética , Rhodococcus equi/genética , Fatores de Virulência/genética , Infecções por Actinomycetales/epidemiologia , Infecções por Actinomycetales/microbiologia , Animais , Brasil/epidemiologia , Cruzamento , Doenças dos Cavalos/epidemiologia , Humanos , Esterco/microbiologia , Epidemiologia Molecular , Família Multigênica/genética , Reação em Cadeia da Polimerase/métodos , Rhodococcus equi/isolamento & purificação , Rhodococcus equi/patogenicidade , Microbiologia do Solo , Virulência/genéticaRESUMO
A 2-year-old intact male domestic shorthaired cat presented with a chronic, nodular, ulcerated, cutaneous lesion on the right thoracic limb. Histological and cytological examination revealed a pyogranulomatous inflammation with basophilic organisms in the macrophages. A virulent form of Rhodococcus equi containing an 87 kb type I (VapA) virulence plasmid was identified from cultures of biopsy samples. This report describes the clinicopathological features, plasmid profile and virulence of this case of R equi infection.
Assuntos
Infecções por Actinomycetales/veterinária , Doenças do Gato/microbiologia , Rhodococcus equi , Infecções por Actinomycetales/microbiologia , Infecções por Actinomycetales/patologia , Animais , Doenças do Gato/patologia , Gatos , DNA Bacteriano/análise , Evolução Fatal , Masculino , Plasmídeos/genética , Rhodococcus equi/genética , Rhodococcus equi/patogenicidade , Virulência/genéticaRESUMO
Rhodococcus equi is a gram-positive, facultative intracellular bacterium which infects macrophages and causes rhodococcal pneumonia and enteritis in foals. Recently, this agent has been recognized as an opportunistic pathogen for immunocompromised humans. Several murine experimental models have been used to study R. equi infection. High (H(IV-A)) and Low (L(IV-A)) antibody (Ab)-producers mice were obtained by bi-directional genetic selections for their ability to produce antibodies against sheep and human erythrocytes (Selection IV-A). These lines maintain their phenotypes of high and low responders also for other antigens than those of selection (multispecific effect). A higher macrophage activity in L(IV-A) mice has been described for several intracellular infectious agents, which could be responsible for their intense macrophage antigens (Ag)-handling and low Ab production. Due to these differences, L(IV-A) mice were found to exhibit a better performance to trigger an effective immune response towards intracellular pathogens. The objective of this work was to characterize the immune response of Selection IV-A against R. equi. H(IV-A) and L(IV-A) mice were infected with 2.0x10(6) CFU of ATCC 33701+R. equi by intravenous route. With regards to bacterial clearance and survival assays, L(IV-A) mice were more resistant than H(IV-A) mice to virulent R. equi. L(IV-A) mice presented a higher hydrogen peroxide (H2O2) and nitric oxide (NO) endogenous production by splenic macrophages than H(IV-A) mice. L(IV-A) expressed the most intense cellular response, available by the Delayed-Type Hypersensitivity (DTH) reaction, which activated macrophages and produced more H2O2 and NO. The three times higher specific antibodies titres in H(IV-A) indicated that Selection IV-A maintained the multispecific effect and the polygenic control of humoral and cellular responses also to R. equi.
Assuntos
Infecções por Actinomycetales/imunologia , Anticorpos Antibacterianos/sangue , Rhodococcus equi/imunologia , Infecções por Actinomycetales/microbiologia , Animais , Contagem de Colônia Microbiana , Modelos Animais de Doenças , Feminino , Peróxido de Hidrogênio/metabolismo , Hipersensibilidade Tardia , Fígado/microbiologia , Pulmão/microbiologia , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Óxido Nítrico/metabolismo , Rhodococcus equi/patogenicidade , Rhodococcus equi/fisiologia , Baço/microbiologia , Análise de SobrevidaRESUMO
Rodococose constitui-se na infecção causada por Rhodococcus equi, cocobacilo que se multiplica no interior de macrófagos. Este agente patogênico foi primeiramente isolado em 1923 e é capaz de infectar diversos mamíferos. Este trabalho reúne breve revisão bibliográfica e relato de um caso. O primeiro relato envolvendo seres humanos aconteceu em 1967, e a maioria dos casos ocorrem em indivíduos com defeitos na imunidade celular que têm contato com o solo. Desde a primeira descrição em pacientes com Aids, já foram descritos 228 casos clínicos. São mais freqüentes as formas pneumônicas com formação de abscessos. Alguns casos estão associados ao desenvolvimento de malacoplaquia. Destacamos que: 1) a rodococose é uma infecção oportunista que ocorre em pacientes com estágios avançados de imunodepressão; 2) deve ser suspeitada em pacientes imunodeprimidos com focos de infecção pulmonar; 3) o sucesso terapêutico da rodococose está relacionado ao rápido diagnóstico etiológico.
Assuntos
Humanos , Masculino , Adulto , Soropositividade para HIV , Malacoplasia , Pneumopatias/diagnóstico , Rhodococcus , Rhodococcus equi/patogenicidade , Prognóstico , Sinais e Sintomas , TerapêuticaRESUMO
OBJECTIVE: To compare isolates of Rhodococcus equi on the basis of geographic source and virulence status by use of pulsed-field gel electrophoresis (PFGE). SAMPLE POPULATION: 290 isolates of R equi (218 virulent isolates from foals and 72 avirulent isolates from feces, soil, and respiratory tract samples) obtained between 1985 and 2000 from horses and horse farms from 4 countries. PROCEDURE: DNA from isolates was digested with the restriction enzyme Asel and tested by use of PFGE. Products were analyzed for similarities in banding patterns by use of dendrograms. A similarity matrix was constructed for isolates, and the matrix was tested for nonrandom distributions of similarity values with respect to groupings of interest. RESULTS: There was little grouping of isolates on the basis of country, virulence status, or region within Texas. Isolates of R equi were generally < 80% similar, as determined by use of PFGE. Isolates from the same farm generally were rarely of the same strain. CONCLUSIONS AND CLINICAL RELEVANCE: Considerable chromosomal variability exists among isolates of R equiobtained from the same farm, sites withinTexas, or among countries from various continents. Only rarely will it be possible to link infections to a given site or region on the basis of analysis of isolates by use of PFGE of chromosomal DNA.
Assuntos
Infecções por Actinomycetales/microbiologia , Infecções por Actinomycetales/veterinária , Doenças dos Cavalos/microbiologia , Rhodococcus equi/genética , Rhodococcus equi/isolamento & purificação , Infecções por Actinomycetales/epidemiologia , Animais , Argentina/epidemiologia , DNA Bacteriano/análise , Eletroforese em Gel de Campo Pulsado , Evolução Molecular , Cavalos/microbiologia , Irlanda/epidemiologia , Japão/epidemiologia , Filogenia , Rhodococcus equi/patogenicidade , Texas/epidemiologia , VirulênciaRESUMO
A malakoplakia-like lesion was detected in a pleural biopsy from an AIDS patient presenting clinical and radiologic features of pneumonia. Cultures of bronchoalveolar lavage and pleural fluid evidenced Rhodococcus equi as the causative agent of pleuro-pulmonary infection. Immunochemical characterization of the R. equi isolate showed the presence of a strain similar to the ATCC 33704 reference strain presenting the capsular antigen of serotype 4, and the intermediate virulence-associated antigen of 20-kDa. Histopathology of the patient's pleural biopsy showed plaques of macrophages interspersed with lymphocytes, and intracytoplasmic cocci and bacilli in macrophages, which were variably acid-fast positive. Immunohistochemistry of cocci, bacilli and their degradation products resulted strongly positive when stained with a mouse monoclonal antibody (MAb) produced against the 20-kDa antigen. This finding could have important implications for the pathogenicity of R. equi for human beings, since we do not know yet all the factors involved in the formation of malakoplakia. Indeed, the results obtained in the present study, taken together with the results obtained for pigs inoculated with R. equi strains of intermediate virulence (Madarame et al. 1998), raise the possibility that most strains presenting the 20-kDa antigen may be capable of inducing malakoplakia. If this hypothesis is confirmed by immunohistochemical analysis of human pulmonary malakoplakia cases due to R. equi, the detection of this antigen may be extremely helpful in the diagnosis and treatment of such patients. This is the first report of R. equi infection in human beings that suggests a relationship between pleural malakoplakia and the virulence-associated antigen of 20-kDa.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Infecções por Actinomycetales/microbiologia , Antígenos de Bactérias/análise , Malacoplasia/microbiologia , Doenças Pleurais/microbiologia , Rhodococcus equi/imunologia , Infecções Oportunistas Relacionadas com a AIDS/imunologia , Infecções Oportunistas Relacionadas com a AIDS/patologia , Infecções por Actinomycetales/imunologia , Infecções por Actinomycetales/patologia , Adulto , Animais , Anticorpos Monoclonais , Humanos , Técnicas Imunoenzimáticas , Macrófagos Alveolares/microbiologia , Macrófagos Alveolares/patologia , Malacoplasia/imunologia , Malacoplasia/patologia , Masculino , Camundongos , Peso Molecular , Doenças Pleurais/imunologia , Doenças Pleurais/patologia , Rhodococcus equi/patogenicidade , Abuso de Substâncias por Via Intravenosa , Virulência/imunologiaRESUMO
Diversity of virulence-associated antigens of Rhodococcus equi was detected among thirteen strains isolated from AIDS patients on two continents. One out of four Brazilian isolates presented the virulence-associated antigen of 15- to 17-kDa, and the other three isolates had the 20-kDa virulence-associated antigen. In contrast, only three out of nine Italian isolates were positive for virulence-associated antigens - two for the 15- to 17-kDa antigen and one for the 20-kDa antigen. In four other Italian strains, one or more other low-molecular-weight antigens were identified. Because of R. equi variability and host immune dysfunction, no characteristic antibody profile was detected among patients, although the presence of specific antibodies in serum samples suggested prognostic value: good patient outcome and recovery from pneumonia were correlated with R. equi antibody detection, whereas the lack or disappearance of specific antibodies, mainly those to low-molecular-weight antigens, was correlated with disease progression and patient death. These results confirmed the nonobligatory presence of the well-known virulence-associated antigens for the pathogenicity of R. equi in humans, and also the diversity of R. equi strains isolated from AIDS patients, which may be related to the geographic origin of the isolates or may be a consequence of the route of R. equi transmission in different countries. Some mechanisms underlying the results obtained are discussed, suggesting immune complex formation during the progress of the disease.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Infecções Oportunistas Relacionadas com a AIDS/imunologia , Infecções por Actinomycetales/diagnóstico , Infecções por Actinomycetales/imunologia , Anticorpos Antibacterianos/sangue , Rhodococcus equi/imunologia , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Infecções por Actinomycetales/microbiologia , Infecções por Actinomycetales/veterinária , Animais , Antígenos de Bactérias/imunologia , Eletroforese em Gel de Poliacrilamida , Doenças dos Cavalos/imunologia , Doenças dos Cavalos/microbiologia , Cavalos , Humanos , Immunoblotting , Rhodococcus equi/classificação , Rhodococcus equi/genética , Rhodococcus equi/patogenicidade , VirulênciaRESUMO
An R. equi vaccine, prepared under conditions which induce the expression of many antigens, and which has given encouraging results in field trials, was analyzed by SDS-PAGE and immunoblots and compared with other R. equi preparations: a preparation made in with the same technique from a nonvirulent isolate (virulence associated protein negative, VapA-negative); a whole cell preparation of a VapA-positive R. equi, prepared as a standard bacterin; and a semipurified VapA preparation (APTX). The antigens in these preparations were analyzed using hyperimmune sera (from adult horses vaccinated with the R. equi vaccine), passively and actively immunized foals' sera, asymptomatic but serologically positive foals' sera sera from R. equi pneumonic foals, an equine APTX antiserum, and a VapA monoclonal antibody (Mab). The vaccine under study had many proteins in high concentrations. Hyperimmune sera reacted strongly with vaccine antigens in the high molecular weight regions. In the low molecular weight range, it reacted in the 14 and less kDa zone. Sera from passively immunized foals reacted similarly but not so strongly. Actively immunized foals gave very weak reactions. With the APTX extract, the Mab reacted with bands at 15-17, 44 and 66 kDa; it reacted weakly with the whole cell and not with the VapA-negative preparations. The APTX antiserum and the Mab reacted strongly with the vaccine at the 14 and less kDa zone, and also with bands at 21, 44 and 66 kDa and very tenuously at 18 kDa, but not in the expected 15-17 kDa zone, suggesting that the native form of VapA is altered but without loss of antigenicity in the vaccine preparation. Our results suggest that other higher molecular weight antigens, in addition to VapA, may be important in inducing antibodies that protect young foals from R. equi pneumonia. These antigens are in high concentrations and in an immunogenic form in the vaccine.
Assuntos
Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/imunologia , Vacinas Bacterianas , Lipoproteínas/imunologia , Rhodococcus equi/imunologia , Fatores de Virulência , Animais , Anticorpos Monoclonais , Formação de Anticorpos , Reações Antígeno-Anticorpo , Antígenos de Bactérias/análise , Proteínas de Bactérias/análise , Eletroforese em Gel de Poliacrilamida , Cavalos , Immunoblotting , Lipoproteínas/análise , Rhodococcus equi/patogenicidade , VirulênciaRESUMO
O presente trabalho de revisäo detalha informaçöes sobre o papel do Rhodococcus equi como agente patogênico de infecçöes em animais e no homem. Inicialmente, säo destacados dados da literatura sobre sua participaçäo na patogênese de infecçöes, incluindo referências sobre os principais métodos de isolamento, identificaçäo, composiçäo antigênica, fatores de virulência, suscetibilidade antimicrobiana e procedimentos quanto ao tratamento. Os autores reafirmam a necessidade de maiores atençöes ao importante papel patogênico desempenhado pelo Rhodococcus equi na etiologia da broncopneumonia em potros e nos processos infecciosos em pacientes imunodeprimidos por drogas, linfoma, leucemia e pela Síndrome da Imunodeficiência Adquirida (AIDS).
Assuntos
Animais , Infecções por Actinomycetales , Rhodococcus equi/patogenicidade , Infecções por Actinomycetales/diagnóstico , Infecções por Actinomycetales/tratamento farmacológicoRESUMO
Se comunican dos casos de pacientes seropositivos para el Virus de la Inmunodeficiencia Humana, con diagnóstico de neumonía cavitaria crónica por Rhodococcus equi, que presentan los primeros casos de esta patología registrados en la bibliografía latinoamericana de acuerdo con nuestra búsqueda. Se resumen las diferencias en las formas de presentación en pacientes inmunocompetentes e inmunocomprometidos, con una revisión de los casos reportados en la literatura internacional. Uno de los pacientes permitió evaluar la eficiencia terapéutica del tratamiento indicado