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Journal of Veterinary Internal Medicine 2011Pneumonia is a major cause of disease and death in foals. Rhodococcus equi, a gram-positive facultative intracellular pathogen, is a common cause of pneumonia in foals.... (Review)
Review
Pneumonia is a major cause of disease and death in foals. Rhodococcus equi, a gram-positive facultative intracellular pathogen, is a common cause of pneumonia in foals. This article reviews the clinical manifestations of infection caused by R. equi in foals and summarizes current knowledge regarding mechanisms of virulence of, and immunity to, R. equi. A complementary consensus statement providing recommendations for the diagnosis, treatment, control, and prevention of infections caused by R. equi in foals can be found in the same issue of the Journal.
Topics: Actinomycetales Infections; Animals; Horse Diseases; Horses; Rhodococcus equi; Virulence
PubMed: 22092609
DOI: 10.1111/j.1939-1676.2011.00804.x -
Animals : An Open Access Journal From... May 2022is an important veterinary pathogen that takes the lives of many foals every year. With the emergence and spread of MDR to current antimicrobial treatment, new tools...
is an important veterinary pathogen that takes the lives of many foals every year. With the emergence and spread of MDR to current antimicrobial treatment, new tools that can provide a fast and accurate diagnosis of the disease and antimicrobial resistance profile are needed. Here, we have developed and analytically validated a multiplex qPCR for the simultaneous detection of and related macrolide resistance genes in equine respiratory samples. The three sets of oligos designed in this study to identify housekeeping gene and macrolide resistance genes (46) and (51) showed high analytic sensitivity with a limit of detection (LOD) individually and in combination below 12 complete genome copies per PCR reaction, and an amplification efficiency between 90% and 147%. Additionally, our multiplex qPCR shows high specificity in in-silico analysis. Furthermore, it did not present any cross-reaction with normal flora from the equine respiratory tract, nor commonly encountered respiratory pathogens in horses or other genetically close organisms. Our new quantitative PCR is a trustable tool that will improve the speed of infection diagnosis, as well as helping in treatment selection.
PubMed: 35565598
DOI: 10.3390/ani12091172 -
Frontiers in Microbiology 2021ATCC13557 was selected as a model organism to study oestrogen degradation based on its previous ability to degrade 17α-ethinylestradiol (EE2). Biodegradation...
ATCC13557 was selected as a model organism to study oestrogen degradation based on its previous ability to degrade 17α-ethinylestradiol (EE2). Biodegradation experiments revealed that ATCC13557 was unable to metabolise EE2. However, it was able to metabolise E2 with the major metabolite being E1 with no further degradation of E1. However, the conversion of E2 into E1 was incomplete, with 11.2 and 50.6% of E2 degraded in mixed (E1-E2-EE2) and E2-only conditions, respectively. Therefore, the metabolic pathway of E2 degradation by ATCC13557 may have two possible pathways. The genome of ATCC13557 was sequenced, assembled, and mapped for the first time. The genome analysis allowed the identification of genes possibly responsible for the observed biodegradation characteristics of ATCC13557. Several genes within ATCC13557 are similar, but not identical in sequence, to those identified within the genomes of other oestrogen degrading bacteria, including strain SJTE-1 and strain KC8. Homologous gene sequences coding for enzymes potentially involved in oestrogen degradation, most commonly a cytochrome P450 monooxygenase (), extradiol dioxygenase (), and 17β-hydroxysteroid dehydrogenase (), were identified within the genome of ATCC13557. These searches also revealed a gene cluster potentially coding for enzymes involved in steroid/oestrogen degradation; 3-carboxyethylcatechol 2,3-dioxygenase, 2-hydroxymuconic semialdehyde hydrolase, 3-alpha-(or 20-beta)-hydroxysteroid dehydrogenase, 3-(3-hydroxy-phenyl)propionate hydroxylase, cytochrome P450 monooxygenase, and 3-oxosteroid 1-dehydrogenase. Further, the searches revealed steroid hormone metabolism gene clusters from the 9, 10- pathway, therefore ATCC13557 also has the potential to metabolise other steroid hormones such as cholesterol.
PubMed: 34276604
DOI: 10.3389/fmicb.2021.670928 -
International Journal of Medical... Aug 2021Rhodococcus equi is a saprophytic soil bacterium and intracellular pathogen that causes refractory suppurative pneumonia in foals and has emerged as a pathogenic cause...
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 × 10 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.
Topics: Actinomycetales Infections; Animals; Genomics; Horses; Humans; Mice; Plasmids; Rhodococcus; Rhodococcus equi; Virulence
PubMed: 34280738
DOI: 10.1016/j.ijmm.2021.151519 -
Emerging Infectious Diseases Feb 2021Multidrug resistance has been detected in the animal and zoonotic human pathogen Rhodococcus equi after mass macrolide/rifampin antibioprophylaxis in endemically...
Multidrug resistance has been detected in the animal and zoonotic human pathogen Rhodococcus equi after mass macrolide/rifampin antibioprophylaxis in endemically affected equine farms in the United States. Multidrug-resistant (MDR) R. equi emerged upon acquisition of pRERm46, a conjugative plasmid conferring resistance to macrolides, lincosamides, streptogramins, and, as we describe, tetracycline. Phylogenomic analyses indicate that the increasing prevalence of MDR R. equi since it was first documented in 2002 is caused by a clone, R. equi 2287, attributable to coselection of pRErm46 with a chromosomal rpoB mutation driven by macrolide/rifampin therapy. pRErm46 spillover to other R. equi genotypes has given rise to a novel MDR clone, G2016, associated with a distinct rpoB mutation. Our findings illustrate that overuse of antimicrobial prophylaxis in animals can generate MDR pathogens with zoonotic potential. MDR R. equi and pRErm46-mediated resistance are currently disseminating in the United States and are likely to spread internationally through horse movements.
Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Drug Resistance, Bacterial; Horse Diseases; Horses; Macrolides; Rhodococcus; Rhodococcus equi; United States
PubMed: 33496218
DOI: 10.3201/eid2702.203030 -
Microbiology Spectrum Jun 2022A previously reported method for evaluating the intracellular growth of Rhodococcus equi using enhanced green fluorescent protein is unsuitable for the quantitative...
A previously reported method for evaluating the intracellular growth of Rhodococcus equi using enhanced green fluorescent protein is unsuitable for the quantitative evaluation of the entire sample because the signal can be detected only in the excitation region. Therefore, we created an autobioluminescent using luciferase (). First, we connected to the functional promoter P and introduced it into the chromosomes of ATCC33701 and ATCC33701_P-. Luminescence was detected in both transformants, and a correlation between the bacterial number and luminescence intensity in the logarithmic phase was observed, indicating that is functionally and quantitatively expressed in . The luminescence of ATCC33701 was significantly higher than that of ATCC33701_P- at 24 h after infection with J774A.1. Next, RNA-Seq analysis of ATCC33701 to search for endogenous high-expression promoters resulted in the upstream sequences of RS29370, RS41760, and being selected as candidates. Luminescence was detected in each transformant expressing the using these upstream sequences. We examined the luminescence intensity by coexpressing the gene, an enhancer of the luciferase reaction, with . The luminescence intensity of the coexpressing transformant was significantly enhanced in J774A.1 compared with the non-coexpressing transformant. Finally, we examined the luminescence . The luminescence signals in the organs peaked on the third day following the administration of ATCC33701 derivatives in mice, but no luminescence signal was detected when the ATCC33701_P- derivative was administered. The autologous bioluminescent method described herein will enhance the and quantitative analysis of proliferation. We established an autologous bioluminescent strain of and a method to evaluate its proliferation and quantitatively. This method overcomes the weakness of the fluorescence detection system that only measures the site of excitation light irradiation. It is expected to be used as an and growth evaluation method with excellent quantitative properties. In addition, it was suggested that the selection of a promoter that expresses could produce a luminescence with high intensity. Although this method needs further improvement, such as creating transformants that can maintain high luminescence intensity regardless of environmental changes such as temperature fluctuations, it is possible to observe bacterial growth over time in mice without killing them. Therefore, this method can be used to not only evaluate the pathogenicity of various wild and gene-deficient strains but also to screen preventive and therapeutic methods such as vaccines.
Topics: Actinomycetales Infections; Animals; Bacterial Proteins; Mice; Rhodococcus equi; Virulence Factors
PubMed: 35638814
DOI: 10.1128/spectrum.00758-22 -
Frontiers in Cellular and Infection... 2022is a zoonotic pathogen that can cause fatal disease in patients who are immunocompromised. At present, the epidemiology and pathogenic mechanisms of infection are not...
is a zoonotic pathogen that can cause fatal disease in patients who are immunocompromised. At present, the epidemiology and pathogenic mechanisms of infection are not clear. This study characterized the genomes of 53 strains from different sources. Pan-genome analysis showed that all strains contained 11481 pan genes, including 3690 core genes and 602 ~ 1079 accessory genes. Functional annotation of pan genome focused on the genes related to basic lifestyle, such as the storage and expression of metabolic and genetic information. Phylogenetic analysis based on pan-genome showed that the strains were clustered into six clades, which was not directly related to the isolation location and host source. Also, a total of 84 virulence genes were predicted in 53 strains. These virulence factors can be divided into 20 categories related to substance metabolism, secreted protein and immune escape. Meanwhile, six antibiotic resistance genes ( and ) were detected, and all strains carried related to rifamycin resistance. In addition, 28 plasmids were found in the 53 strains, belonging to Type-A (n = 14), Type-B (n = 8) and Type-N (n = 6), respectively. The genetic structures of the same type of plasmid were highly similar. In conclusion, strains show different genomic characteristics, virulence-related genes, potential drug resistance and virulence plasmid structures, which may be conducive to the evolution of its pathogenesis.
Topics: Humans; Phylogeny; Plasmids; Rhodococcus equi; Rifamycins; Virulence
PubMed: 35252029
DOI: 10.3389/fcimb.2022.807610 -
FEMS Microbiology Reviews Sep 2009The soil actinomycete Rhodococcus equi is a pulmonary pathogen of young horses and AIDS patients. As a facultative intracellular bacterium, R. equi survives and... (Review)
Review
The soil actinomycete Rhodococcus equi is a pulmonary pathogen of young horses and AIDS patients. As a facultative intracellular bacterium, R. equi survives and multiplies in macrophages and establishes its specific niche inside the host cell. Recent research into chromosomal virulence factors and into the role of virulence plasmids in infection and host tropism has presented novel aspects of R. equi infection biology and pathogenicity. This review will focus on new findings in R. equi biology, the trafficking of R. equi-containing vacuoles inside host cells, factors involved in virulence and host resistance and on host-pathogen interaction on organismal and cellular levels.
Topics: AIDS-Related Opportunistic Infections; Actinomycetales Infections; Animals; Bacterial Proteins; Gene Expression Regulation, Bacterial; Horse Diseases; Horses; Host-Pathogen Interactions; Humans; Macrophages; Rhodococcus equi; Virulence; Virulence Factors
PubMed: 19453748
DOI: 10.1111/j.1574-6976.2009.00181.x -
Animals : An Open Access Journal From... Oct 2020The aim of this review was to summarize studies on equine rhodococcosis over the last decade. For many years has remained one of the major health challenges in the... (Review)
Review
The aim of this review was to summarize studies on equine rhodococcosis over the last decade. For many years has remained one of the major health challenges in the equine breeding industry worldwide. Recently, many novel approaches and ideas have been described and some of them were initially implemented into the clinical practice. This study reviews a variety of new information about neonatal susceptibility, clinical appearance, considered and applied diagnostic procedures and treatment alternatives, factors limiting accurate prognosis, ideas regarding environmental management and prophylaxis considerations. Although multiple research were conducted, the main problems such as high morbidity and mortality, a lack of reliable prevention strategies and treatment limitations are still unresolved and require further scientific effort.
PubMed: 33081047
DOI: 10.3390/ani10101910 -
Differential Effects of Virulence-Associated Proteins on Macrophages and Artificial Lipid Membranes.Microbiology Spectrum Feb 2023irulence-ssociated rotein (VapA) of Rhodococcus equi is a pathogenicity factor required for the multiplication of virulent strains within spacious macrophage vacuoles....
irulence-ssociated rotein (VapA) of Rhodococcus equi is a pathogenicity factor required for the multiplication of virulent strains within spacious macrophage vacuoles. The production of VapA is characteristic for isolates from pneumonic foals. VapB and VapN proteins in isolates from infected pig (VapB) and cattle (VapN) have amino acid sequences very similar to VapA and consequently have been assumed to be its functional correlates. Using model membrane experiments, phagosome pH acidification analysis, lysosome size measurements, protein partitioning, and degradation assays, we provide support for the view that VapA and VapN promote intracellular multiplication of by neutralizing the pH of the -containing vacuole. VapB does not neutralize vacuole pH, is not as membrane active as VapA, and does not support intracellular multiplication. This study also shows that the size of the sometimes enormous -containing vacuoles or the partitioning of purified Vaps into organic phases are not features that have predictive value for virulence of , whereas the ability of Vaps to increase phagosome pH is coupled to virulence. Rhodococcus equi is a major cause of life-threatening pneumonia in foals and occasionally in immunocompromised persons. Virulence-associated protein A (VapA) promotes multiplication in lung macrophages, which are the major host cells during foal infection. In this study, we compare cellular, biochemical, and biophysical phenotypes associated with VapA to those of VapB (typically produced by isolates from pigs) or VapN (isolates from cattle). Our data support the hypothesis that only some Vaps support multiplication in macrophages by pH neutralization of the phagosomes that inhabit.
PubMed: 36786596
DOI: 10.1128/spectrum.03417-22