Cloning and sequences of inducible and constitutive macrolide resistance genes in<i>Staphylococcus aureus</i>that correspond to an ABC transporter

Matsuoka, Masao; Janosi, Laszlo; Endou, Kikutarou; Nakajima, Yoshinori

doi:10.1111/j.1574-6968.1999.tb08830.x

Cited by 32 publications

(9 citation statements)

References 23 publications

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“…20,32 . In the present study, the msr (A) gene was detected in isolates having MIC I of 8 mg/L, supporting the loss of activity of this gene when cloned in E. coli 33 . The other ATP binding transporter studied, Msr(D), it was detected independently of the presence of Mef(A).…”

Section: Discussionsupporting

confidence: 83%

Azithromycin resistance levels and mechanisms in Escherichia coli

Gomes

Ruiz-Roldán

Mateu

et al. 2019

Sci Rep

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Despite azithromycin being used in some countries to treat infections caused by Gram-negative pathogens, no resistance breakpoint for Escherichia coli exists. The aim of this study was to analyse the levels and mechanisms of azithromycin resistance in E. coli . The presence of chromosomal ( rplD, rplV and 23 S rRNA ) mutations, 10 macrolide resistance genes (MRGs) and efflux pump overexpression was determined in 343 E. coli isolates. Overall, 89 (25.9%) isolates had MICs ≥ 32 mg/L to azithromycin, decreasing to 42 (12.2%) when assayed in the presence of Phe-Arg-β-Napthylamide, with 35 of these 42 possessing at least one MRG. Efflux pumps played a role in azithromycin resistance affecting the Minimal Inhibitory Concentration (MIC) levels of 91.2% isolates whereas chromosomal alterations seem to have a minimal role. At least one MRG was found in 22.7% of the isolates with mph (A) being the most commonly found gene. The mph (A) gene plays the main role in the development of azithromycin resistance and 93% of the mph (A)-carrying isolates showed a MIC of 32 mg/L. In the absence of a specific resistance breakpoint our results suggest a MIC of 32 mg/L to be considered in order to detect isolates carrying mechanisms able to confer azithromycin resistance.

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Section: Discussionsupporting

confidence: 83%

Azithromycin resistance levels and mechanisms in Escherichia coli

Gomes

Ruiz-Roldán

Mateu

et al. 2019

Sci Rep

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“…In contrast to the use of radiolabeled antibiotics and measurement by liquid scintillation counter [8,16,17], we lysed the cells, isolated the target compounds, and determined their concentrations by LC-MS/MS, the “gold standard” for the identification and quantification of small molecules [19,20]. During the sample preparation procedure, we focused on the rapid separation of bacterial cells from culture medium and minimization of cell membrane disruption.…”

Section: Discussionmentioning

confidence: 99%

“…In a recent study, Sharkey et al provided the first direct evidence that Vga and Lsa-type proteins confer resistance by acting directly on the ribosome [15]. However, previous studies showed that Staphylococcus aureus and Staphylococcus haemolyticus carrying msr or vga exhibited decreased intracellular accumulation of the corresponding target antibiotics [8,16,17], although this may also result from ribosomal protection [8]. Until now, little has been known regarding the resistance mechanism of optrA .…”

Section: Introductionmentioning

confidence: 99%

Intracellular Accumulation of Linezolid and Florfenicol in OptrA-Producing Enterococcus faecalis and Staphylococcus aureus

Wang

et al. 2018

Molecules

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The optrA gene, which confers transferable resistance to oxazolidinones and phenicols, is defined as an ATP-binding cassette (ABC) transporter but lacks transmembrane domains. The resistance mechanism of optrA and whether it involves antibiotic efflux or ribosomal protection remain unclear. In this study, we determined the MIC values of all bacterial strains by broth microdilution, and used ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry to quantitatively determine the intracellular concentrations of linezolid and florfenicol in Enterococcus faecalis and Staphylococcus aureus. Linezolid and florfenicol both accumulated in susceptible strains and optrA-carrying strains of E. faecalis and S. aureus. No significant differences were observed in the patterns of drug accumulation among E. faecalis JH2-2, E. faecalis JH2-2/pAM401, and E. faecalis JH2-2/pAM401+optrA, but also among S. aureus RN4220, S. aureus RN4220/pAM401, and S. aureus RN4220/pAM401+optrA. ANOVA scores also suggested similar accumulation conditions of the two target compounds in susceptible strains and optrA-carrying strains. Based on our findings, the mechanism of optrA-mediated resistance to oxazolidinones and phenicols obviously does not involve active efflux and the OptrA protein does not confer resistance via efflux like other ABC transporters.

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“…MLS resistance genes (ermA, ermB, ermC, msrA/B, lnuA, lnuB, and lsaA) were identified by multiple PCR methods on 60 isolates from the total number of tested enterococcal strains for which the MLS resistance phenotype was determined using primers, whose sequences have been previously published (Table 1) [12,[18][19][20].…”

Section: Isolation Of Dna and Pcr Primersmentioning

confidence: 99%

Human enterococcal isolates as reservoirs for macrolide-lincosamide-streptogramin and other resistance genes

Mišić

Kocić

Arsović³

et al. 2022

J Antibiot

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According to recent studies, the importance of MLS (macrolide-lincosamide-streptogramin) resistance phenotypes and genes in enterococci are reflected in the fact that they represent reservoirs of MLS resistance genes. The aim of this study was to investigate distribution of MLS resistance genes and phenotypes in community-and hospital-acquired enterococcal isolates and to determine their prevalence. The MLS resistance phenotypes (cMLSb, iMLSb, M/MSb, and L/LSa) were determined in 245 enterococcal isolates were characterized using the double-disc diffusion method. Specific primers were chosen from database sequences for detection of the MLS resistance genes (ermA, ermB, ermC, msrA/B, lnuA, lnuB, and lsaA) in 60 isolates of enterococci by end-point PCR. There was no linezolid-resistant enterococcal isolate. Only one vancomycinresistant (0.6%) isolate was found and it occurred in a community-acquired enterococcal isolate. The most frequent MLS resistance phenotype among enterococcal isolates was cMLSb (79.7% community-and 67.9% hospital-acquired). The most common identified MLS resistance genes among enterococcal isolates were lsaA (52.9% community-and 33.3% hospitalacquired) and ermB (17.6% community-and 33.3% hospital-acquired). The most prevalent MLS gene combination was lnuA + lsaA (five enterococcal isolates). The ermB gene encoded cMLSb phenotype, and it was identified in only one isolate that displayed iMLSb resistance phenotype. Based on the results obtained, we can conclude that the most frequent MLS resistance phenotype among enterococcal isolates was cMLSb. Surprisingly, a vancomycin-resistant enterococcal isolate was identified in a community-acquired enterococcal isolate. This study shows that enterococci may represent a major reservoir of ermB, lsaA, and lnuA genes.

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Cloning and sequences of inducible and constitutive macrolide resistance genes inStaphylococcus aureusthat correspond to an ABC transporter

Cited by 32 publications

References 23 publications

Azithromycin resistance levels and mechanisms in Escherichia coli

Azithromycin resistance levels and mechanisms in Escherichia coli

Intracellular Accumulation of Linezolid and Florfenicol in OptrA-Producing Enterococcus faecalis and Staphylococcus aureus

Human enterococcal isolates as reservoirs for macrolide-lincosamide-streptogramin and other resistance genes

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