Resistance studies of erythromycin and rifampin for Rhodococcus equi over a 10-year period

Buckley, Tom; McManamon, E; Stanbridge, Siobhan

doi:10.1186/2046-0481-60-12-728

Cited by 29 publications

(30 citation statements)

References 16 publications

(24 reference statements)

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“…Treatment of R. equi infection must be based on the results of antimicrobial susceptibility tests because there is no standard drug regimen for R. equi infection in humans (Roda et al 2009) and the emergence of some strains resistant to various antibiotics has been reported within the last 10 years (Buckley et al 2007). R. equi isolates in our study showed resistance to β-lactam agents, in agreement with the results described by Roda et al (2009).…”

Section: Discussionsupporting

confidence: 82%

“…Interpretation categories beta-lactamase inhibitor, the activity was significantly increased (98.04% for amoxicillin-clavulanate), confirming the correlation of β-lactamase enzyme production and resistance. Because R. equi is an intracellular bacteria, the infection can be treated with macrolides, such as erythromycin and rifampicin (Heidmann et al 2006, Buckley et al 2007). The macrolides tested in our study, azithromycin and clarithromycin, were 100% effective, while erythromycin was 98% effective against the R. equi isolates.…”

Section: Discussionmentioning

confidence: 99%

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Rhodococcus equi isolation from sputum of patients with suspected tuberculosis

Silva

Miyata²,

Sato

et al. 2010

Mem. Inst. Oswaldo Cruz

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Rhodococcus equi has emerged as an opportunistic pathogen associated with pulmonary, invasive or systemic infections in immunocompromised patients. We report the identification of 51 R. equi isolates found in sputum samples of 546 individuals suspected to have pulmonary tuberculosis in two Public Health Hospital Units in Brazil.The epidemiology of R. equi infection as well as the phenotypic identification and drug susceptibility profile of isolates are described in this paper.Key words: Rhodococcus equi -identification -tuberculosis -antimicrobial profile -epidemiologyThe genus Rhodococcus belongs to the group of nocardioform, Gram-positive rods containing mycolic acids in the cell wall; this group also includes the genera My� cobacterium, Nocardia, Corynebacterium, Dietzia, Gor� donia, Millisia, Segniliparus, Skermania, Tsukamurella and Williamsia (Soddell et al. 2006a, b, Tsitko et al. 2006). The genus Rhodococcus was discovered by Zopf in 1891 (Goodfellow & Alderson 1977) and comprises 30 species, of which Rhodococcus equi is considered the most opportunistic pathogen in mammals, including humans (Meijer & Prescott 2004). The first case of human infection was reported in 1967 in a patient presenting with a pulmonary abscess. The two first cases that occurred in Brazil were reported by Severo et al. (2001). However, with the AIDS epidemic, the number of patients infected by R. equi has grown (Roda et al. 2009). R. equi also causes infection in patients with lymphoma, chronic renal failure, alcoholism, lung cancer, leukaemia, diabetes mellitus and other immunodeficient syndromes. Some cases have been reported in which the infection can also occur in immunocompetent hosts (von Bargen & Haas 2009).When incubated aerobically at 37°C, R. equi grows efficiently in the majority of nonselective culture media, including media used in mycobacteria isolation and produces irregular, smooth and mucoid colonies that turn a shade of salmon pink to yellow after a week of growth (Prescott 1991). R. equi appears coccoid on stained smears of clinical specimens, especially purulent material and tissue (obtained by biopsy, during surgery and upon autopsy). However, long rods have been reported in clinical specimens isolated from blood, sputum and bronchial lavage fluid In general, R. equi is biochemically non-reactive, has no proteolytic activity and fails to oxidize or ferment carbohydrates, with the exception of glucose, which is oxidized by R. equi in 14 days. R. equi is strictly aerobic, catalase positive, oxidase negative and mostly urease positive. R. equi produces soluble "equi factors" that are associated with phospholipase and cholesterol oxidase activity and interact with phospholipase D of Listeria ivanovii to induce complete haemolysis of sheep erythrocytes (Prescott 1991).The Laboratory of Mycobacteriology at the Adolfo Lutz Institute in Ribeirão Preto (SP, Brazil) has frequently isolated partial acid-fast bacteria from sputum of patients suspected to have pulmonary tuberculosis. Considering the emerging clinical im...

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Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Rhodococcus equi isolation from sputum of patients with suspected tuberculosis

Silva

Miyata²,

Sato

et al. 2010

Mem. Inst. Oswaldo Cruz

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“…Buckley et al (10) highlighted a 2-fold increase in MICs over a 10-year period. Moreover, the emergence of rhodococci resistant to these antibiotics has already been reported in humans and animals (2,7,10,28). This suggests that there may be a problem in the treatment of R. equi infection, and new effective broad-spectrum drugs will be needed in the near future.…”

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confidence: 99%

In Vitro Potential of Equine DEFA1 and eCATH1 as Alternative Antimicrobial Drugs in Rhodococcosis Treatment

Schlusselhuber¹,

Jung

Bruhn³

et al. 2012

Antimicrob Agents Chemother

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f Rhodococcus equi, the causal agent of rhodococcosis, is a severe pathogen of foals but also of immunodeficient humans, causing bronchopneumonia. The pathogen is often found together with Klebsiella pneumoniae or Streptococcus zooepidemicus in foals. Of great concern is the fact that some R. equi strains are already resistant to commonly used antibiotics. In the present study, we evaluated the in vitro potential of two equine antimicrobial peptides (AMPs), eCATH1 and DEFA1, as new drugs against R. equi and its associated pathogens. The peptides led to growth inhibition and death of R. equi and S. zooepidemicus at low micromolar concentrations. Moreover, eCATH1 was able to inhibit growth of K. pneumoniae. Both peptides caused rapid disruption of the R. equi membrane, leading to cell lysis. Interestingly, eCATH1 had a synergic effect together with rifampin. Furthermore, eCATH1 was not cytotoxic against mammalian cells at bacteriolytic concentrations and maintained its high killing activity even at physiological salt concentrations. Our data suggest that equine AMPs, especially eCATH1, may be promising candidates for alternative drugs to control R. equi in mono-and coinfections.

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“…Since then, R. equi resistance to these drugs has been observed (BUCKLEY et al, 2007). In this respect, azithromycin (AZM) and clarithromycin (CLR) have been proposed as alternatives to ERY for the treatment of R. equi infections in foals (JACKS et al, 2003).…”

mentioning

confidence: 99%

“…In vitro, R. equi has to be sensitive to a wide variety of antibiotics, such as aminoglycosides, beta-lactams and second-generation of cephalosporins (GIGUÈRE et al, 2010). However, their ability to replicate in macrophages and neutrophils limited the therapeutic options to drugs able to penetrate in lipophilic environment (BUCKLEY et al, 2007).…”

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confidence: 99%