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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. [ABSTRACT FROM AUTHOR]

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 Nsil 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. [ABSTRACT FROM AUTHOR]

Forty-five foals with Rhodococcus equi infection and pneumonia symptoms were classified into a surviving group and a dead group. Using serum samples, the oxidative stress index (OSI) was determined at the first visit and the follow-up visit. The OSI of the surviving group was significantly lower at the follow-up than that at the first visit. No significant difference was observed between the OSI of the dead group at the first and follow-up visits. In the surviving group, treatment at the first visit mitigated inflammation and reduced OSI. However, in the dead group, poor response to the treatment provided at the first visit led to continued inflammation, and no change was observed the OSI. [ABSTRACT FROM AUTHOR]

• Due to treatment of R-equi pneumonia Il-2 and IL-10 in serum increase • serum INF-γ and INF-α levels suggest persistent clearing of rhodococci • INF-α, INF-γ, IL-2 and IL-10 in serum displays innate immunity Rhodococcus equi (R. equi) , a gram-positive facultative intracellular pathogen, is a common cause of pneumonia in foals and represents a major cause of disease and death. The aim of the present study was to investigate the time-depended changes in White Blood Cells (WBC), basophils (Baso), neutrophils (Neu), lymphocytes (Lymf), monocytes (Mon), eosinophils (Eos), platelet (PLT) counts, fibrinogen (Fbg) concentration, interferon (IFN-α, IFN-γ) and interleukins (IL-2 and IL-10) in foals with clinical R. equi pneumonia. The main treatment was with azithromycin-rifampicin for 14 days. Blood was sampled prior to, 7 and 14 days after starting therapy. Treatment was associated with significantly decreased counts of WBC, (25.6 ± 6.7 and 14.2 ± 2,7 × 103/ml), Neu (18.6 ±6.2 and 10.7 ± 3.1 × 103/ml), Mon (1.5 ± 0.5 and 0.9 ± 0.2 × 103/ml) and Fbg (539 ± 124 and 287 ± 26 g/dl) between day 0 and day 14. IL-2 and IL-10 concentrations were significantly increased (P = 0.028, P = 0.013, respectively) after treatment, whereas IFN-α and IFN-γ concentrations were not. The diagnostic potentials of INF-α, INF-γ, IL-2 and IL-10 per se seems not very high, however, the study suggests that the activity change of selected interleukins in the course of the disease may be associated with amelioration. We concluded that patterns of serum concentration changes of INF-α, INF-γ, IL-2 and IL-10 may help in the study of the innate immune response in foals during infection and treatment of R. equi pneumonia. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objectives: This retrospective study aimed to describe clinical manifestations, diagnostic options, radiological features, therapeutic plans and outcomes for cats infected with Rhodococcus equi. Methods: Forty cats aged between 2 months and 11 years old (median 6 months) that were definitively diagnosed with rhodococcosis between 2012 and 2018 were recruited in this study. Medical records were reviewed for information on signalment, history, clinical presentation, diagnostic testing, treatment plans and clinical outcomes. Results: Of the 40 cats, 36 showed the pulmonary form of the disease, with 35 (87.5%) presenting with dyspnoea, while four cats presented with only cutaneous lesions. Mean body temperature was 38.7 ± 0.2°C. Dyspnoea was noted in 87.5% of the cats. Leukocytosis (58.3%) with band neutrophilia (83.3%), monocytosis (58.3%) and thrombocytopenia (55.5%) were prominent findings in the haematology reports. Hyperproteinaemia (61.1%) with hypoalbuminaemia (22.2%) and hyperglobulinaemia (63.8%) with a low albumin:globulin ratio (38.9%) were prominent features of blood biochemistry reports. An alveolar–interstitial pattern was noted in 75% of pre-thoracocentesis radiographs. Pleural effusion, hepatomegaly, thoracic lymphadenopathy and atelectasis of any lung lobe were seen in 88.9%, 75%, 41.7% and 36.1% of cats, respectively. Overall, the mortality rate was 67.5% in both forms. Conclusions and relevance: Clinicians should be aware that feline rhodococcosis manifests as a pulmonary disease at a much higher rate than previously reported. Further studies are required to address the epidemiology, pathophysiology, disease management and prognosis of feline rhodococcosis. The role of immunosuppression as a predisposing factor in feline rhodococcosis requires further investigation. [ABSTRACT FROM AUTHOR]

We document the causes and pathological findings in 50 cases of equine pneumonia and pleuritis in Southern Brazil. Suppurative (17/50), pyogranulomatous (14/50), aspiration (5/50), mycotic (4/50), bronchointerstitial (3/50), embolic (3/50) and eosinophilic granulomatous pneumonia (1/50) and pleuritis (3/50) were the main conditions identified. Streptococcus spp. were identified in 11 cases of suppurative pneumonia. Suppurative pneumonia was further divided into acute (8/17), subacute (6/17) and chronic (3/17) based on the morphological pattern of lesions. Rhodococcus equi was identified in all cases of pyogranulomatous pneumonia and exclusively affected young foals. [ABSTRACT FROM AUTHOR]

Rhodococcus equi infection in horses is common and is characterized by pyogranulomatous pneumonia and ulcerative enterocolitis. R. equi clinical disease in cattle, however, is rare and typically manifests as granulomatous lymphadenitis discovered in the abattoir. A 19-mo-old female Santa Gertrudis had a history of intermittent inappetence and weight loss for a 3-mo period before euthanasia. Gross and histologic examination revealed severe, chronic, ulcerative, and granulomatous inflammation in the tongue, pharynx, and small intestine. Also, the heifer had severe, granulomatous pharyngeal and mesenteric lymphadenitis. Bacterial cultures from the ileum, tongue, and liver yielded numerous-to-moderate numbers of R. equi. PCR analysis of the isolate detected the linear virulence plasmid vapN, which is often identified in bovine isolates (traA - and vapN -positive). The bacteria also lack the circular plasmids vapA and vapB that are associated with virulence in horses and swine, respectively. We report herein an atypical and unusual clinical presentation of R. equi infection in cattle, which has zoonotic potential. [ABSTRACT FROM AUTHOR]

We report herein Rhodococcus equi infection in an 11-y-old, male llama with a history of diarrhea and endoparasitism. Postmortem examination revealed granulomatous and ulcerative enteritis, pyogranulomatous mesenteric lymphadenitis, fibrinosuppurative peritonitis, and granulomatous hepatitis. Intralesional macrophages were laden with gram-positive cocci. Bacteriology identified R. equi, and cultures tested positive for R. equi choE and vapA genes by PCR. This case expands the reported spectrum of lesions associated with R. equi infections in llamas from pyogranulomatous bronchopneumonia and peripheral lymphadenitis to pyogranulomatous mesenteric lymphadenitis and enteritis. We also link a R. equi that is carrying the virulent-associated protein gene VapA to clinical disease in New World camelids. [ABSTRACT FROM AUTHOR]

The distinction between lower respiratory tract infections caused by Rhodococcus equi and those caused by other pathogens is difficult. The aim of this retrospective study was to describe cytological findings in bronchoalveolar lavage fluid (BALF) of foals with pneumonia caused by R. equi or other bacteria. Nineteen foals aged from 3 weeks to 6 months with evidence of respiratory disease between 2015 and 2016 were selected from the database of the Veterinary Teaching Hospital "Mario Modenato" of the University of Pisa. Eight foals of 19 (42.1%) had R. equi pneumonia, whereas 11 of 19 (57.9%) had another bacterial pneumonia. R. equi –positive foals had statistically significant higher total nucleated cell count (P =.02) and neutrophils percentage (P =.002) than R. equi –negative ones. Macrophages proportion (P =.01) was lower in R. equi –positive than in R. equi –negative foals. Bronchoalveolar lavage is a quite easy procedure that can be performed in the field with minimal equipment required. Here we reported significant differences in the cellular composition of BALF that can be used to differentiate foals with R. equi bronchopneumonia from those with other bacterial pneumonias, whereas waiting for culture results. • Differentiating between Rhodococcus equi and other bacterial pneumonia is difficult. • Bronchoalveolar lavage fluid (BALF) culture for R. equi pneumonia is time-consuming. • Cytology of BALF can identify foals with R. equi from other bacterial pneumonias. • Bronchoalveolar lavage fluid in foals with R. equi pneumonia can be used while waiting for culture result. [ABSTRACT FROM AUTHOR]

Transfusing foals with Rhodococcus equi hyperimmune plasma (REHIP) is a standard practice at many horse-breeding farms to help prevent R. equi pneumonia. At many large breeding farms, pneumonia is most commonly recognized as subclinical based on thoracic ultrasonography findings. The efficacy of REHIP transfusion and the impact of the volume of plasma transfused for reducing the cumulative incidence of subclinical R. equi pneumonia are unknown. A retrospective cohort study was conducted among foals born and residing through weaning at a large breeding farm. Foals were transfused with either 0 L (n = 2 foals), 1 L (n = 85 foals), or 2 L (n = 62 foals) of REHIP within 36 hours of birth. Volume transfused was principally based on intended use of the foals. All foals at the ranch were routinely screened using thoracic ultrasonography at 5, 7, and 9 weeks of age to detect subclinical pneumonia attributed to R. equi based on farm history. The proportion of the foals receiving < 1 L REHIP that developed subclinical pneumonia (32%; 26/82) was significantly (P =.0068; chi-squared test) greater than that among foals transfused with 2 L of REHIP (12%; 8/68). Despite the important limitations of this observational study, it provides evidence supporting the need for well-designed clinical trials to evaluate the impact of the use and dose of REHIP for preventing subclinical pneumonia. Reducing the incidence of subclinical pneumonia is important because reducing antibiotic treatment of subclinical cases will decrease selection pressure for antimicrobial resistance in R. equi. • First evidence that transfusion of plasma hyperimmune against Rhodococcus equi can reduce the incidence of subclinical pneumonia. • Transfusion of 2 L is clinically more effective than 1 L or less for preventing subclinical R. equi pneumonia. • Foals can be safely transfused with 2 L of plasma hyperimmune against Rhodococcus equi. • Because of inherent biases of observational studies, well-designed clinical trials are needed to substantiate the evidence presented here. [ABSTRACT FROM AUTHOR]

• Rhodococcus equi causes subclinical to severe disease in foals. • There is a lack of effective preventive measures for the disease in endemic farms. • Due to the increase in antimicrobial treatment, macrolide resistance has emerged. • The emergence of antimicrobial resistance is a veterinary and public health concern. • Alternatives to antimicrobials to treat and prevent R. equi infections are needed. Rhodococcus equi , a gram-positive facultative intracellular pathogen and a soil saprophyte, is one of the most common causes of pneumonia in young foals. It poses a threat to the economy in endemic horse-breeding farms and to animal welfare annually. Many farms use thoracic ultrasonographic screening and antimicrobial treatment of subclinically affected foals as a preventive measure against severe R. equi infections. The wide use antimicrobials to treat subclinically affected foals has contributed to the emergence of multidrug resistant (MDR)- R. equi in both clinical isolates from sick foals and in the environment of horse-breeding farms. Alternatives to treat foals infected with MDR- R. equi are scarce and the impact of the emergence of MDR- R. equi in the environment of farms is still unknown. The aim of this review is to discuss the emergence of MDR- R. equi in the United States and the challenges faced to guide antimicrobial use practices. Reduction of antimicrobial use at horse-breeding farms is essential for the preservation of antimicrobial efficacy and, ultimately, human, animal, and environmental health. [ABSTRACT FROM AUTHOR]

Rhodococcus equi was isolated from the granulomatous lesions of the lung, kidney, liver, and hepatic, mesenteric, and abomasum lymph nodes of a Japanese black heifer. R. equi isolates were analyzed by polymerase chain reaction for virulence-associated protein genes. The vapN gene was detected in all the isolates examined. This is the first report in which vapN-positive R. equi was isolated from cattle in Japan. [ABSTRACT FROM AUTHOR]

Rhodococcus equi is a facultative intracellular bacterium that can escape from bactericidal mechanisms associated with phagocytosis. Virulence-associated protein A (VapA), encoded on a virulence-associated plasmid, is essential for intracellular survival in macrophages, but its function is not known. Here, we show that the extracellular addition of recombinant glutathione S-transferase (GST)-VapA fusion protein rescued the intracellular replication defect of a mutant lacking the vapA gene. Furthermore, the virulence-plasmid-cured strain could also multiply to nearly wild-type levels by the addition of GST-VapA. The present data suggest that VapA can alter the intraphagocytic environment, thereby affecting its suitability for the growth of R. equi. [ABSTRACT FROM AUTHOR]

Summary Immune Reconstitution Syndrome (IRIS) has been associated with a variety of infections in patients with human immunodeficiency virus (HIV). However, we are reporting the first case of IRIS secondary to Rhodococcus equi ( R. equi ) in a patient with HIV. We report the case of a 48-year-old male found to have HIV infection in the setting of Burkitt's lymphoma. While on anti-retroviral therapy and chemotherapy, he had developed IRIS secondary to R. equi that manifested as a cavitating pneumonia. This report outlines the successful management of the R. equi infection with the use of a combination of antibiotics, radiographic follow up and suppressive antibiotic while on chemotherapy. [ABSTRACT FROM AUTHOR]

Transgenic cotton GK 12 producing Cry1Ab/Ac proteins can effectively control lepidopteran pests in agriculture. However, there are concerns that GK 12 has unintended side-effects on actinobacterial communities in the soil. Actinobacterial communities in the rhizosphere soil of cottons were analyzed by real-time PCR (qPCR) and denaturing gradient gel electrophoresis (DGGE) at different growth stages in three annual replications under field conditions. Population sizes and community structures of Actinobacteria were markedly affected by natural variations in years, growth stages and cultivars. No significant differences were found in population sizes (excepting at budding in 2009), community structures, and Shannon indices of Actinobacteria (excepting at budding in 2010) between the GK 12 and its non-transgenic parent Simian 3, although there were differences between the GK 12 and the conventional cotton DP 5415. Phylogenetic analysis of DGGE band sequences indicated that Cellulosimicrobium sp. and Rhodococcus sp. only occurred in the GK 12 and the Simian 3. The dominant Actinobacteria did not differ between the GK 12 and the Simian 3. In conclusion, the overall impacts of the GK 12 on actinobacterial communities in the rhizosphere soil, based on qPCR and DGGE, were not significant during three continuous years in northern China. [ABSTRACT FROM AUTHOR]

Steroid estrogens have been detected in oceans, rivers, lakes, groundwaters, soils, and even urban water supply systems, thereby inevitably imposing serious impacts on human health and ecological safety. Indeed, many estrogen-degrading bacterial strains and degradation pathways have been reported, with the 4,5-seco pathway being particularly important. However, few studies have evaluated the use of the 4,5-seco pathway by actinomycetes to degrade 17β-estradiol (E2). In this study, 5 genes involved in E2 degradation were identified in the Rhodococcus equi DSSKP-R-001 (R-001) genome and then heterologously expressed to confirm their functions. The transformation of E2 with hsd17b14 reached 63.7% within 30 h, resulting in transformation into estrone (E1). Furthermore, we found that At1g12200 -encoded flavin-binding monooxygenase (FMO At1g12200) can transform E1 at a rate of 51.6% within 30 h and can transform E1 into 4-hydroxyestrone (4-OH E1). In addition, catA and hsaC genes were identified to further transform 4-OH E1 at a rate of 97–99%, and this reaction was accomplished by C–C cleavage at the C4 position of the A ring of 4-OH E1. This study represents the first report on the roles of these genes in estrogen degradation and provides new insights into the mechanisms of microbial estrogen metabolism and a better understanding of E2 degradation via the 4,5-seco pathway by actinomycetes. [Display omitted] • Rhodococcus equi can degrade E2 through the 4,5-seco pathway. • Hsd17b14 and At1g12200 play key roles in the initial steps of E2 degradation. • For the first time, At1g12200, and hsaC are confirmed to operate in estrogen degradation. [ABSTRACT FROM AUTHOR]

Rhodococcus equi is the most important causative bacterium of severe pneumonia in foals. We report herein the development of a specific loop-mediated isothermal amplification (LAMP) assay, which targets a gene encoding vapA for detecting virulent R. equi. The detection limit of the LAMP assay was 104 colony forming units (CFU)/mL, which was equal to 10 CFU/reaction. The clinical efficacy of the LAMP assay was compared with those of 2 published PCR-based methods: nested PCR and quantitative real-time (q)PCR. Agreements between bacterial culture, which is the gold standard for detection of R. equi, and each of the 3 molecular tests were measured by calculating a kappa coefficient. The kappa coefficients of the LAMP (0.760), nested PCR (0.583), and qPCR (0.888) indicated substantial agreement, moderate agreement, and almost perfect agreement, respectively. Although the clinical efficacy of LAMP was not the best among the 3 methods tested, LAMP could be more easily introduced into less well-equipped clinics because it does not require special equipment (such as a thermocycler) for gene amplification. Veterinary practitioners could diagnose R. equi pneumonia more quickly by using LAMP and could use the results to select an appropriate initial treatment. [ABSTRACT FROM AUTHOR]

Rhodococcus equi is the causative agent of rhodococcosis in horses, resulting in significant morbidity and mortality in foals. This bacterium has also been isolated from a variety of animals and is being increasingly reported as a cause of infection in humans, mainly in immunosuppressed individuals. Laboratory diagnostics of R. equi infections based only on conventional microbiological methods shows low accuracy and can lead to misidentification. The objective of the study was to develop and evaluate a real-time PCR assay for direct detection of R. equi in various clinical specimens, including tissue samples. The species-specific region of the gene encoding R. equi cholesterol oxidase, choE, was used as a qPCR-target. The diagnostic applicability of the assay was confirmed by testing various tissue specimens obtained from horses with clinical signs of rhodoccocal infection and swine submaxillary lymph nodes. The rate of R. equi detection in clinical specimens by the developed assay was higher in comparison to the culture method (90% vs. 60.0% of positive samples) and conventional PCR (90.0% vs. 20.0% of positive samples). In case of 13 samples that were negative in the culture-based method, R. equi was detected by the developed assay. Only in one case, it gave negative result for culture-positive sample. The assay may provide a simple and rapid tool to complement the classical methods of R. equi detection based on culture and phenotypic identification of isolates, as the performed evaluation indicated a high specificity and accuracy of the results. [ABSTRACT FROM AUTHOR]

Copyright of Pesquisa Veterinaria Brasileira is the property of Colegio Brasileiro de Patologia Animal - CBPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rhodococcus equi is one of the most important pathogens of foals, in which it causes a disease manifesting in pyogranulomatous bronchopneumonia, abscesses, lymphadenitis or ulcerative enterocolitis. R. equi can be pathogenic to other domestic and wild animals and humans as well. Although, R. equi is prevalent in India, the work carried out in our country has not gone much beyond isolation of organism from clinical cases of foal pneumonia. Therefore, the present study was carried out for characterization of R. equi strains isolated from clinical cases based on plasmid markers (fraA, vapA and vapB genes) and antibiotic sensitivity. In the present study, 298 samples (nasal swab, 136; fecal sample, 130; soil, 28; tissue, 4) were collected and processed for isolation, identification, and characterization of R. equi via biochemical test, antimicrobial susceptibility test and PCR. A total of 28 R. equi isolates could be recovered from clinical samples. All the 28 isolates were found sensitive to chloramphenicol, erythromycin, oxytetracycline, ciprofloxacine, neomycin and rifampin while resistant to ampicillin, trimethoprim, sulphadiazine, cloxacin, amikacin, cephalexin, and kanamycin in in vitro antimicrobial assay. PCR typing based on plasmid gene markers: traA, vapA, and vapB revealed that vapA plasmid was present in 26 isolates whereas it was absent in 2 isolates. Periodic monitoring of horse farm before and after foaling season is recommended for diagnosis of R. equi and initiating requisite bio-security and therapeutic measures. [ABSTRACT FROM AUTHOR]

Prescottella equi (formerly Rhodococcus equi) is an intracellular pathogen that causes pyogranulomatous pneumonia in Thoroughbred foals. There is currently no vaccine available for the prevention of this disease in foals despite years of research. Cell mediated immunity is considered crucial for overcoming an infection caused by this pathogen. The virulence associated protein (VapA) is a well characterized immunogenic protein associated with this pathogen and was used to develop DNA and recombinant protein vaccines in this study. Vaccine candidates and live P. equi based vaccine were tested in BALB/c mice. Mice were challenged with virulent P.equi 2 weeks following the last boost and IgG subtypes and bacterial clearance from spleen and liver determined. The DNA vaccine elicited a significant IgG2a response indicating a Th1 biased immune response. The IFN gamma response from DNA and recombinant VapA vaccinated mice was moderate. The results of the challenge study showed that neither the recombinant VapA protein nor DNA vaccine enhanced clearance of P. equi in this model. [ABSTRACT FROM AUTHOR]

The article examines the susceptibility of Rhodococcus equi isolates against antimicrobials and the emergence and relation of antimicrobial multiple resistance index and vapA gene. The study verifies different resistance levels against antibiotics used in rodococosis treatment. It notes the absence of drug resistance in its restricted use in human rodococosis treatment. It also features the value of more caution and restrictive measures in using the drugs in infections caused by R. equi.

Copyright of RPDI - Revista Portuguesa de Doenças Infecciosas is the property of Sociedade Portuguesa de Doencas Infecciosas e Microbiologia Clinica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article discusses a study which determined the risk factors associated with the incidence of Rhodococcus equi (R. equi) pneumonia in Basse-Normandie, France. Data gathered from 93 farms was processed through univariate analysis and conditional logistic regression analysis. Researchers attributed R. equi infections to factors such as exceeded maximum broodmare capacity, late births, shared use of medical facilities among mares, and dust exposure. The study also cited that length of time in farm usage for horse husbandry was not a significant factor in the degree of contamination for R. equi pneumonia.

Summary: The aim of the present study was to develop an immunocytochemical procedure for the early detection and demonstration of Rhodococcus equi in smears of tracheal aspirates taken from live foals in field conditions. Tracheal wash samples were collected from thoroughbred foals, aged 1–5 months and located in studs around Bursa and Istanbul, Turkey. Some foals were suspected of having R. equi infection on the basis of clinical examination (n =56) and others were unaffected control animals (n =54). Serum samples were also collected from each foal for testing for the presence of R. equi-specific antibody by enzyme linked immunosorbent assay (ELISA). Thirty-six of the control foals (66.7%) and 37 of the affected foals (66.1%) were seropositive for R. equi. Immunocytochemical labelling was detected in the smears from 73.2% of the affected foals and 70.4% of the control foals. For both ELISA and immunocytochemistry (ICC), there was no significant difference between the affected and control foals (P >0.05) and there was no significant difference between the two test modalities (P >0.05). ICC may therefore have similar diagnostic utility when compared with ELISA. There is no clear relationship between clinical signs and ELISA or ICC positivity. [ABSTRACT FROM AUTHOR]

Summary: A 26-month-old thoroughbred colt with a 4-month history of continuous diarrhoea and weight loss was subject to necropsy examination. The small intestinal mucosa was thickened and this change particularly affected the terminal ileum. Microscopical examination revealed multifocal epithelial hyperplasia, with multifocal granulomas and marked lymphocytic infiltration of the lamina propria. Numerous gram-negative argyrophilic curved bacilli were observed within the cytoplasm of affected enterocytes. Macrophages and epithelioid cells forming the granulomas had abundant, lightly eosinophilic, foamy cytoplasm, with occasional large, clear vacuoles containing gram-positive coccobacilli. Immunohistochemical studies suggested that the argyrophilic bacilli were Lawsonia intracellularis and the gram-positive coccobacilli were Rhodococcus equi. L. intracellularis-specific DNA fragments were amplified from the affected ileocaecal mucosa by polymerase chain reaction. Virulent R. equi (VapA positive) was isolated in pure culture from the liver and mesenteric lymph nodes. These results suggested that the two intracytoplasmic organisms had induced multifocal proliferative and granulomatous enteritis accompanied by severe and extensive lymphocytic infiltration. [ABSTRACT FROM AUTHOR]

Abstract: Rhodococcus equi (R equi) pneumonia is an important cause of disease and death in foals. Feces from mares can contain R equi, including virulent R equi, and thus may act as a source of the bacteria at horse breeding farms. A previous report documented that every mare at a farm in central Kentucky shed virulent R equi in at least one of four fecal samples collected serially during the periparturient period. The objective of this study was to assess the extent to which this high prevalence of fecal shedding could be replicated at other horse breeding farms. The frequency of detection of R equi and virulent R equi in fecal samples was studied among 131 mares from 24 farms in central Kentucky. The proportions of fecal samples from mares containing R equi and virulent R equi were 95% and 76%, respectively. These findings indicate that R equi and virulent R equi may be isolated with high frequency from feces of mares at breeding farms in central Kentucky, and that mares are a source of virulent R equi for the environment of their foals. [Copyright &y& Elsevier]

A 2-month-old foal with septic shock and severe respiratory distress was referred to the Veterinary Teaching Hospital. Due to poor prognosis, the foal was euthanized. Histopathology showed lesions suggestive of Rhodococcus equi infection associated with a diffuse interstitial infiltrate of foamy macrophages and syncytial cells presenting large acidophilic intranuclear inclusion bodies, fibrin exudates and hyaline membranes. Bacteriological examination from lung and respiratory exudates confirmed R. equi infection, whilst immunohistochemistry and PCR yielded a positive result for Equid herpesvirus type 1 (EHV-1). Several etiologies have been proposed for bronchointerstitial pneumonia in foals, although a multifactorial origin for this lesional pattern could be possible. This work is the first one describing a combined EHV-1 and R. equi infection in a foal affected with bronchointerstitial pneumonia. [ABSTRACT FROM AUTHOR]

Abstract: A relative immunodeficiency of young foals is considered to account for the increased susceptibility of foals to infectious diseases, including pneumonia caused by Rhodococcus equi. In this report, peripheral blood mononuclear cells (PBMCs) from healthy foals at 14 and 56 days of age, or from their dams, were incubated with three stimulatory and one nonstimulatory (control) synthetic cytosine-phosphate-guanosine oligodeoxynucleotides (CpG-ODNs), and mRNA expression of tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), interleukin (IL) -6, IL-8, IL12-p35, and IL-12p40 were determined. Results indicated that synthetic CpG-ODNs can induce strong, rapid cytokine responses in healthy foals and adult horses. B-class CpG-ODNs 2135 and 2142 induced greater messenger RNA (mRNA) expression of IFN-γ, IL-6, and IL-12p40 than the C-class CpG-ODN 2395 in foal PBMCs. In foals, B-class CpG-ODNs induced IFN-γ, IL-6, and IL-12P40 mRNA expression that was similar to or higher in magnitude than that observed in adult horses. These observations indicate that CpG-ODNs might be useful as immunomodulators or as potential adjuvants for vaccines to aid in preventing R. equi pneumonia and other bacterial diseases of foals. [Copyright &y& Elsevier]

Abstract: The objective of this study was to assess the ability of prophylactically administered gallium maltolate (GaM) to inhibit growth or kill Rhodococcus equi within murine macrophage-like (J774A.1) cells. Cells were treated with three different doses of GaM or a single dose of maltol (equivalent to the concentration present in the highest dose of GaM studied); they were then infected with virulent R. equi and incubated. Quantitative cultures of R. equi from lysed macrophages were obtained at 0, 24, 48, and 72 hours. All GaM dosages resulted in significant reductions of intracellular R. equi compared with untreated control cells, and a dose–response effect was evident. Maltol treatment alone had no significant effect on intracellular R. equi concentrations compared with untreated control cells. Results suggest the potential usefulness of gallium maltolate for the prevention or control of R. equi infections. [Copyright &y& Elsevier]

Abstract: Rhodococcus equi infection is considered the most common cause of pneumonia in foals less than 6 months of age. Immunization of foals and/or mares may become a procedure of choice for prevention. The present work documents the antibody response of neonate foals to R. equi virulence-associated protein (Vap) vaccine candidate peptides. A mixture of 4 R. equi (ATCC 33701) Vap peptides was selected based on their hydrophilicity and recognition by naturally acquired IgG antibodies from 13 adult horses and 33 neonate foals from France and Japan. They were combined with a water-based nanoparticular adjuvant to promote a protective immune response including both Th1 cytokine pattern and antibody response. A single intramuscular injection resulted in an IgG antibody response 30 days later, although inconsistently. In responding animals, no bias in IgG subclass distribution was observed, and antibody response was associated with enhanced serum opsonic activity. In conclusion, data indicate that synthetic Vap peptides combined with nanoparticular adjuvant were immunogenic and resulted in a significant increase in IgG antibodies against the corresponding virulent R. equi strain in a majority of foals. [Copyright &y& Elsevier]

Rhodococcus equi is a Gram-positive facultative intracellular bacterial pathogen and the most common cause of severe infectious pneumonia in foals. The pathogen is ubiquitous in the environment, but becomes concentrated in breeding farm situations due to its ability to reproduce in the gastrointestinal tract of herbivores. Foals may be exposed to the organism soon after birth; overt infection results in variable number of foals due to a combination of pathogen virulence, host susceptibility, and infective dose of the organism. Herd health programs using passive transfer of antibodies, especially with transfusions of equine hyperimmune plasma, can decrease incidence rates on affected premises, but rarely prevent infection in all susceptible individuals. An effective vaccine is not currently available. Combined therapy of clinically affected individuals using macrolide antibiotics combined with rifampin has improved outcome, including both morbidity and mortality. [Copyright &y& Elsevier]

Abstract: Rhodococcus equi is a significant pathogen in foals predominantly causing a pyogranulomatous bronchopneumonia. Many vaccine candidates have been tested for the prevention of R. equi disease in foals. However, none of these have been developed for widespread commercial use. Previous studies have shown that a Th1 immune response is imperative for the protection of foals against R. equi disease. In this study a DNA and a protein vaccine based upon the well-characterised R. equi virulence-associated protein VapA were developed. The vaccines were tested in the BALB/c murine model and the results showed that both vaccine candidates elicited a Th1-type response in the host. Upon co-administration of an IL-12 expression plasmid with the DNA vaccine, an increase in the Th1 response was observed. However, when mice were challenged with 1.5×107 virulent R. equi ATCC 33701 none of the vaccinated mice showed protection apart from the mice immunised with live R. equi. These results indicate that despite their immunogenicity the VapA-based DNA and recombinant protein vaccines developed in this study were unable to prevent bacterial replication following a high-dose systemic challenge with virulent R. equi in the BALB/c model. [Copyright &y& Elsevier]

• This study showed the pathogenicity and genomic features of vapN -harboring R. equi. • VapN-producing strains showed the proliferation in cultured macrophages. • VapN-producing strains reproduced fatal necrotizing granulomatous inflammation. • Both VapN-producing and non-producing strains have nearly identical pVAPNs. • More genomic analyses are needed to explain the mechanism of VapN expression. 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. [ABSTRACT FROM AUTHOR]

The article focuses on the differential diagnosis for Rhodococcus equi pneumonia in an AIDS patient. A brief overview is given on the medical history and clinical manifestations of the patient. Topics discussed include the main pattern of lung involvement of Rhodococcus equi pneumonia, the typical histopathological finding of R. equi infection, and the multiple factors of the diagnosis of disease activity in patients with pulmonary tuberculosis.

We present two cases of Rhodococcus equi bacteremia as a cause of sepsis in premature infants who had increasing respiratory distress with multiple episodes of apnea. When we investigated these infants for apnea etiology, blood cultures were taken, and R. equi was confirmed based on the colony characteristics on nutrient agar; extended antibiotherapy was started. R. equi has been identified frequently as an opportunistic pathogen in immunocompromised patients. Infection in immunocompetent patients is rare. R. equi infection in the neonatal period is also rare, and to our knowledge, these are the first cases of R. equi as a sepsis agent in preterm infants. [ABSTRACT FROM AUTHOR]