Characteristics of rifampin-resistant variants obtained from clinical isolates of Staphylococcus aureus

Moorman, David R.; Mandell, Gerald L.

doi:10.1128/aac.20.6.709

Cited by 40 publications

(23 citation statements)

References 18 publications

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“…No change in rifampin MICs from that for the parent strain was observed for any of the derivative isolates. Several reports of rifampin resistance of Legionella species and other bacteria document that the rifampin MICs for the resistant strains are much higher than those for the parent strains as was the case for the L. pneumophila isolates that grew on the gradient and resistance frequency assay plates (1,3,6,14,17,18). It is therefore unlikely that significant rifampin resistance was undetected by the MIC determinations performed in this study.…”

Section: Resultsmentioning

confidence: 60%

Rifampin resistance of Legionella pneumophila is not increased during therapy for experimental Legionnaires disease: study of rifampin resistance using a guinea pig model of Legionnaires disease

Edelstein

1991

Antimicrob Agents Chemother

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Isolates of Legionella pneumophila serogroup 1, obtained from guinea pigs with experimentally induced Legionnaires disease, were tested for rifampin resistance. Thirteen isolates were from animals treated with rifampin alone, four isolates were from animals treated with saline, and three isolates each were from animals treated with erythromycin or erythromycin plus rifampin; all of these isolates were derived from the same parent strain, F889. Most of the isolates were obtained from rifampin-treated animals that survived infection but had persistence of bacteria in their lungs at necropsy. No differences in rifampin agar dilution MICs were detected for the 23 isolates and parent strain that were tested. None of the 13 isolates from animals treated with rifampin alone had a high number of resistant organisms detected by using a rifampin gradient plate assay. Thirteen isolates plus the parent strain were tested by using a quantitative method of determining resistance frequency. Considerable heterogeneity among isolates was observed, but there was no evidence of increased resistance for any treatment group. The range of rifampin resistance frequencies was 10-7 to 10-8. No evidence for rifampin-induced resistance of L. pneumophila was found in this study.

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Section: Resultsmentioning

confidence: 60%

Rifampin resistance of Legionella pneumophila is not increased during therapy for experimental Legionnaires disease: study of rifampin resistance using a guinea pig model of Legionnaires disease

Edelstein

1991

Antimicrob Agents Chemother

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“…Previous studies indicated that the addition of rifampin to the medium tended to turn B. abortus cultures rough and that organisms resistant to rifampin were less virulent than rifampin-susceptible strains (28). RB51 has also been used for comparative evaluation because of its well documented ability in mouse models to confer protection not only against B. abortus infection but also against B. melitensis and B. ovis (19).…”

Section: Discussionmentioning

confidence: 99%

Protective Properties of Rifampin-Resistant Rough Mutants ofBrucella melitensis

et al. 2005

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Vaccination against Brucella infections in animals is usually performed by administration of live attenuated smooth B. abortus strain S19 and B. melitensis strain Rev1. They are proven effective vaccines against B. abortus in cattle and against B. melitensis and B. ovis in sheep and goats, respectively. However, both vaccines have the main drawback of inducing O-polysaccharide-specific antibodies that interfere with serologic diagnosis of disease. In addition, they retain residual virulence, being a cause of abortion in pregnant animals and infection in humans. To overcome these problems, one approach is to develop defined rough mutant Brucella strains lacking O antigen of lipopolysaccharide. B. abortus rough strain RB51, a rifampin-resistant mutant of virulent strain B. abortus 2308, is used as a vaccine against B. abortus infection in cattle in some countries. However, RB51 is not effective in sheep, and there is only preliminary evidence that it is effective in goats. In this study, we tested the efficacies of six rifampin-resistant rough strains of B. melitensis in protecting BALB/c mice exposed to B. melitensis infection. The protective properties, as well as both humoral and cellular immune responses, were assessed in comparison with those provided by B. melitensis Rev1 and B. abortus RB51 vaccines. The results indicated that these rough mutants were able to induce a very good level of protection against B. melitensis infection, similar to that provided by Rev1 and superior to that of RB51, without inducing antibodies to O antigen. In addition, all B. melitensis mutants were able to stimulate good production of gamma interferon. The characteristics of these strains encourage further evaluation of them as alternative vaccines to Rev1 in primary host species.Brucellosis is a major zoonotic disease, widely distributed in humans and domestic and wild animals, especially in developing countries. Among the different species of the Brucella genus, B. abortus and B. melitensis are the most pathogenic and virulent, not only for cattle or for sheep and goats, respectively, but also for other animal species. The occurrence of the disease in humans is largely dependent on the animal reservoir, with the highest rate of human infection in areas where rates of brucellosis in sheep and goats are high (6,35).Brucellosis vaccines are essential elements in control programs. Attenuated B. abortus strain 19 and B. melitensis strain Rev1 are proven effective vaccines; they induce good levels of protection against B. abortus in cattle and against B. melitensis in sheep and goats, preventing premature abortions (7, 30, 31). However, both vaccines have the drawback of inducing Opolysaccharide-specific antibodies that interfere with the discrimination between vaccinated and infected animals during serological screening (7, 31). In addition, they retain pathogenicity and sometimes cause abortion in vaccinated animals (10, 18, 41) and remain infectious for humans (3,5,26). The use of the conjunctival route when administering B. melit...

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“…Rifampicin-resistant (Rif ') isolates of S. aureus have been shown to have reduced virulence (Moorman & Mandel, 1981) and, more recently, it has been demonstrated that Rif' mutants are associated with altered expression of exoprotein virulence factors (Exp-phenotype; Al-Ani et al, 1991). Several relatively specific phenotypic effects have also been described for rifampicin-resistant mutants of a number of Gram-positive and Gram-negative bacteria (Yura & Ishihama, 1979;Jin & Gross, 1989).…”

Section: -7482 0 1992 Sgmmentioning

confidence: 99%

Cloning and physical mapping of the Staphylococcus aureus rplL, rpoB and rpoC genes, encoding ribosomal protein L7/L12 and RNA polymerase subunits and '

Aboshkiwa

Al‐Ani

Coleman

et al. 1992

Journal of General Microbiology

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Using segments of the Escherichia coli rpoB and rpoC genes as heterologous probes, we have identified and cloned an 8.3 kb PstI fragment from the Staphylococcus aureus genome containing the rpoB and rpoC genes, which respectively encode the p and p' subunits of DNA-directed RNA polymerase. This region is almost certainly equivalent to the riflocus, located near tofus at interval 12/13 on the S. aureus linkage map. Limited DNA sequencing revealed the gene order rpoB-rpoC (transcribed from left to right) and identified the rplL gene, encoding ribosomal protein L7/L12, upstream of rpoB. This and other evidence suggests that the rpoBC genes of S. aureus form part of a large gene cluster encoding components of the transcription and translation apparatus which is well-conserved in other eubacteria.

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Characteristics of rifampin-resistant variants obtained from clinical isolates of Staphylococcus aureus

Cited by 40 publications

References 18 publications

Rifampin resistance of Legionella pneumophila is not increased during therapy for experimental Legionnaires disease: study of rifampin resistance using a guinea pig model of Legionnaires disease

Rifampin resistance of Legionella pneumophila is not increased during therapy for experimental Legionnaires disease: study of rifampin resistance using a guinea pig model of Legionnaires disease

Protective Properties of Rifampin-Resistant Rough Mutants ofBrucella melitensis

Cloning and physical mapping of the Staphylococcus aureus rplL, rpoB and rpoC genes, encoding ribosomal protein L7/L12 and RNA polymerase subunits and '

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