scholarly journals The type of anticoagulant used for plasma collection significantly affects in vitro Rhodococcus equi assays

2021 ◽  
Vol 53 (S56) ◽  
pp. 19-20
Keyword(s):  
Rhodococcus Equi ◽  
Plasma Collection

scholarly journals The Type of Anticoagulant Used for Plasma Collection Affects in Vitro Rhodococcus Equi Assays

2021 ◽  
Author(s):  
Alejandra Antonella Rivolta ◽  
Dana Christine Pittman ◽  
Amanda J Kappes ◽  
Robert K Stancil ◽  
Clark Kogan ◽  
...  
Keyword(s):  
Veterinary Medicine ◽  
Direct Effect ◽  
Bacterial Growth ◽  
Rhodococcus Equi ◽  
Macrophage Infection ◽  
Negative Effect ◽  
Bacterial Replication ◽  
Delayed Growth ◽  
Plasma Collection

Abstract Objective: The efficacy of Rhodococcus equi-specific hyperimmune plasma (HIP) is usually evaluated in vitro. Anticoagulants (AC) used for plasma collection can negatively impact bacterial replication but their effect on R. equi growth has not been evaluated. The aim of this study was to establish the effect that AC routinely used in veterinary medicine (ACD, K2EDTA, Li Heparin, and Na Citrate) have on in vitro R. equi growth. To assess this, in vitro assays commonly used to test HIP efficacy (direct effect on microorganism and macrophage infection), were performed using each AC and non-treated bacteria. Results: There was no direct effect of ACD, Li Heparin or Na Citrate on R. equi growth. These AC significantly (p < 0.05) delayed growth for 12 h following opsonization. The number of R. equi colonies after macrophage infection was significantly (p < 0.05) lower 72h post-opsonization with Na Citrate. K2EDTA inhibited the formation of R. equi colonies by 12 h in all the assays. In conclusion, AC should be taken into consideration when interpreting in vitro results as their negative effect on bacterial growth may be mistakenly interpreted as HIP efficacy. ACD and Li Heparin appear more appropriate for the selected assays.

scholarly journals Dimetilsulfóxido - DMSO no teste de sensibilidade microbiana in vitro em cepas de Rhodococcus equi isoladas de afecções pulmonares em potros

2001 ◽  
Vol 31 (5) ◽  
pp. 889-892 ◽  
Author(s):  
Márcio Garcia Ribeiro ◽  
Aldo Santana de Carvalho Filho ◽  
Fernando José Paganini Listoni
Keyword(s):  
Rhodococcus Equi

Comparou-se a sensibilidade microbiana in vitro de isolados de Rhodococcus equi pelo teste padrão de difusão com discos, com o modificado, pela adição de 5% de dimetilsulfóxido-DMSO. Observou-se aumento da sensibilidade do R. equi no teste com DMSO, frente a aminoglicosídeos (canamicina, amicacina, estreptomicina) e ao cloranfenicol, enquanto para a eritromicina e derivados ß-lactâmicos (penicilina G, cefalosporinas, amoxicilina, oxacilina), constatou-se redução da sensibilidade do agente.

scholarly journals In vitro performances of novel co-spray-dried azithromycin/rifampicin microparticles for Rhodococcus equi disease treatment

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Elisa Rampacci ◽  
Maria Luisa Marenzoni ◽  
Elisabetta Chiaradia ◽  
Fabrizio Passamonti ◽  
Maurizio Ricci ◽  
...  
Keyword(s):  
Rhodococcus Equi ◽  
Disease Treatment ◽  
Spray Dried

scholarly journals Horizontal Spread of Rhodococcus equi Macrolide Resistance Plasmid pRErm46 across Environmental Actinobacteria

2020 ◽  
Vol 86 (9) ◽  
Author(s):  
Sonsiray Álvarez-Narváez ◽  
Steeve Giguère ◽  
Londa J. Berghaus ◽  
Cody Dailey ◽  
José A. Vázquez-Boland
Keyword(s):  
Bacterial Species ◽  
Low Frequency ◽  
Rhodococcus Equi ◽  
Macrolide Resistance ◽  
Conjugative Plasmid ◽  
Bacterial Populations ◽  
Prolonged Incubation ◽  
Content Type ◽  
Host Restriction

ABSTRACT Conjugation is one of the main mechanisms involved in the spread and maintenance of antibiotic resistance in bacterial populations. We recently showed that the emerging macrolide resistance in the soilborne equine and zoonotic pathogen Rhodococcus equi is conferred by the erm(46) gene carried on the 87-kb conjugative plasmid pRErm46. Here, we investigated the conjugal transferability of pRErm46 to 14 representative bacteria likely encountered by R. equi in the environmental habitat. In vitro mating experiments demonstrated conjugation to different members of the genus Rhodococcus as well as to Nocardia and Arthrobacter spp. at frequencies ranging from ∼10−2 to 10−6. pRErm46 transfer was also observed in mating experiments in soil and horse manure, albeit at a low frequency and after prolonged incubation at 22 to 30°C (environmental temperatures), not 37°C. All transconjugants were able to transfer pRErm46 back to R. equi. Conjugation could not be detected with Mycobacterium or Corynebacterium spp. or several members of the more distant phylum Firmicutes such as Enterococcus, Streptococcus, or Staphylococcus. Thus, the pRErm46 host range appears to span several actinobacterial orders with certain host restriction within the Corynebacteriales. All bacterial species that acquired pRErm46 expressed increased macrolide resistance with no significant deleterious impact on fitness, except in the case of Rhodococcus rhodnii. Our results indicate that actinobacterial members of the environmental microbiota can both acquire and transmit the R. equi pRErm46 plasmid and thus potentially contribute to the maintenance and spread of erm(46)-mediated macrolide resistance in equine farms. IMPORTANCE This study demonstrates the efficient horizontal transfer of the Rhodococcus equi conjugative plasmid pRErm46, recently identified as the cause of the emerging macrolide resistance among equine isolates of this pathogen, to and from different environmental Actinobacteria, including a variety of rhodococci as well as Nocardia and Arthrobacter spp. The reported data support the notion that environmental microbiotas may act as reservoirs for the endemic maintenance of antimicrobial resistance in an antibiotic pressurized farm habitat.

scholarly journals Cooperation between Reactive Oxygen and Nitrogen Intermediates in Killing of Rhodococcus equi by Activated Macrophages

2000 ◽  
Vol 68 (6) ◽  
pp. 3587-3593 ◽  
Author(s):  
Patricia A. Darrah ◽  
Mary K. Hondalus ◽  
Quiping Chen ◽  
Harry Ischiropoulos ◽  
David M. Mosser
Keyword(s):  
Nitric Oxide ◽  
Prolonged Exposure ◽  
Rhodococcus Equi ◽  
Activated Macrophages ◽  
Intracellular Killing ◽  
Oxygen Intermediates ◽  
Bacterial Killing ◽  
Ifn Γ

ABSTRACT Rhodococcus equi is a facultative intracellular bacterium of macrophages which can infect immunocompromised humans and young horses. In the present study, we examine the mechanism of host defense against R. equi by using a murine model. We show that bacterial killing is dependent upon the presence of gamma interferon (IFN-γ), which activates macrophages to produce reactive nitrogen and oxygen intermediates. These two radicals combine to form peroxynitrite (ONOO−), which kills R. equi. Mice deficient in the production of either the high-output nitric oxide pathway (iNOS−/−) or the oxidative burst (gp91 phox−/− ) are more susceptible to lethalR. equi infection and display higher bacterial burdens in their livers, spleens, and lungs than wild-type mice. These in vivo observations, which implicate both nitric oxide (NO) and superoxide (O2 −) in bacterial killing, were reexamined in cell-free radical-generating assays. In these assays, R. equi remains fully viable following prolonged exposure to high concentrations of either nitric oxide or superoxide, indicating that neither compound is sufficient to mediate bacterial killing. In contrast, brief exposure of bacteria to ONOO− efficiently kills virulent R. equi. The intracellular killing of bacteria in vitro by activated macrophages correlated with the production of ONOO− in situ. Inhibition of nitric oxide production by activated macrophages by usingN G-monomethyl-l-arginine blocks their production of ONOO− and weakens their ability to control rhodococcal replication. These studies indicate that peroxynitrite mediates the intracellular killing of R. equiby IFN-γ-activated macrophages.

scholarly journals In Vivo Expression of and Cell-Mediated Immune Responses to the Plasmid-Encoded Virulence-Associated Proteins of Rhodococcus equi in Foals

2007 ◽  
Vol 14 (4) ◽  
pp. 369-374 ◽  
Author(s):  
Stephanie Jacks ◽  
Steeve Giguère ◽  
John F. Prescott
Keyword(s):  
Lymph Node ◽  
Rhodococcus Equi ◽  
Interleukin 4 ◽  
Significant Difference ◽  
In Vivo Expression ◽  
Associated Proteins ◽  
Ifn Γ ◽  
Bronchial Lymph Node

ABSTRACT Rhodococcus equi is a facultative intracellular pathogen that causes pneumonia in foals but does not induce disease in adult horses. Virulence of R. equi depends on the presence of a large plasmid, which encodes a family of seven virulence-associated proteins (VapA and VapC to VapH). Eradication of R. equi from the lungs depends on gamma interferon (IFN-γ) production by T lymphocytes. The objectives of the present study were to determine the relative in vivo expression of the vap genes of R. equi in the lungs of infected foals, to determine the recall response of bronchial lymph node (BLN) lymphocytes from foals and adult horses to each of the Vap proteins, and to compare the cytokine profiles of proliferating lymphocytes between foals and adult horses. vapA, vapD, and vapG were preferentially expressed in the lungs of infected foals, and expression of these genes in the lungs was significantly (P < 0.05) higher than that achieved during in vitro growth. VapA and VapC induced the strongest lymphoproliferative responses for foals and adult horses. There was no significant difference in recall lymphoproliferative responses or IFN-γ mRNA expression by bronchial lymph node lymphocytes between foals and adults. In contrast, interleukin 4 (IL-4) expression was significantly higher for adults than for foals for each of the Vap proteins. The ratio of IFN-γ to IL-4 was significantly higher for foals than for adult horses for most Vap proteins. Therefore, foals are immunocompetent and are capable of mounting lymphoproliferative responses of the same magnitude and cytokine phenotype as those of adult horses.

scholarly journals Isolamento e teste de susceptibilidade a antimicrobianos de bactérias em infecções uterinas de éguas

1999 ◽  
Vol 51 (3) ◽  
pp. 213-216 ◽  
Author(s):  
N. Silva ◽  
C.E. Braga ◽  
G.M. Costa ◽  
F.C.F. Lobato
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Proteus Mirabilis ◽  
Rhodococcus Equi ◽  
Minas Gerais ◽  
Streptococcus Equi ◽  
Bacillus Spp

Foram examinados 206 "swabs" cervicais e uterinos de éguas de várias raças, de diversas regiões do Estado de Minas Gerais, durante o período de 1986 a 1996. Cerca de 164 "swabs" foram positivos para a presença de microrganismos causadores de endometrites. Streptococcus equi subsp. zooepidemicus (25,7%) e Escherichia coli (15,1%) foram os principais agentes infecciosos isolados. Outros microrganismos presentes foram: Staphylococcus aureus (9,2%), Streptococcus alfa-hemolítico (9,2%), Pseudomonas aeruginosa (3,9%), Staphylococcus coagulase negativo (6,3%), Bacillus spp. (1,9%), Rhodococcus equi (3,4%) e Proteus mirabilis (1,5%). As provas de susceptibilidade aos antimicrobianos revelaram que amicacina e gentamicina (70,2%), ampicilina (59,5%) e cloranfenicol (59,5%) foram os antibióticos de maior ação in vitro contra os microrganismos isolados.

scholarly journals Strain-to-strain variation of Rhodococcus equi growth and biofilm formation in vitro

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Adina R. Bujold ◽  
Nicholas R. Lani ◽  
Macarena G. Sanz
Keyword(s):  
Biofilm Formation ◽  
Rhodococcus Equi ◽  
Strain Variation
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