Antibiotic resistance plasmids of Staphylococcus aureus and their clinical importance.

Lacey, R. W.

doi:10.1128/mmbr.39.1.1-32.1975

Cited by 115 publications

(63 citation statements)

References 149 publications

(331 reference statements)

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“…The present study has shown that the methicillin resistance expressed by Staphylococcus auras MR-1 is of a very stable phenotype. Unlike many other methicillin-resistant staphylococci, strain MR-1 shows no evidence for heterogeneity of expression of resistance which is unaffected by such factors as growth at low temperatures, growth in the presence of high concentrations of NaCl or in the presence of methicillin [2,3]. The composition of the walls of strain MR-1 was typical of staphylococci and the peptidoglycan was very highly cross-linked.…”

Section: Discussionmentioning

confidence: 91%

“…Methicillin-resistant strains of Staphylococci were first described more than 20 years ago [I] but despite many studies of the characteristics of these strains (for review, see [2,3]) the biochemical mechanisms responsible for expression of resistance remain unknown. Even though some strains produce p-lactamase, resistance does not appear to be due to enzymic hydrolysis of the antibiotic [4] and many resistant strains are 13-lactamase-negative [5].…”

mentioning

confidence: 99%

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Synthesis of Peptidoglycan in vivo in Methicillin‐Resistant Staphylococcus aureus

Wyke

Ward²,

Hayes

1982

European Journal of Biochemistry

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The cell‐wall composition and degree of cross‐linking of peptidoglycan in a strain of Staphylococcus aureus (strain MR‐1) which is highly resistant to methicillin were similar to those of other strains of S. aureus. When the organism was grown in the presence of very low concentrations of methicillin (equivalent to 3 · 10−4× minimum growth‐inhibitory concentration [MGIC] there was a large decrease in the degree of cross‐linking of the peptidoglycan. Increasing concentrations of methicillin (up to 1.25 · 10−2× MGIC) caused a further decrease in cross‐linkage but thereafter a minimum value was reached. This remained unchanged even after growth of the organisms in much higher concentrations of the antibiotic up to 0.3 × minimum growth‐inhibitory concentration. S. aureus MR‐1 was able to grow normally for many generations under these conditions and reduction in cross‐linkage of peptidoglycan was the only change detected in wall chemistry. Growth in the presence of methicillin (up to 0.3 × MGIC) (or other β‐lactam antibiotics) did not lead to an imbalance in the biosynthesis of peptidoglycan since no soluble polymers were secreted into the growth medium and nucleotide‐linked precursors did not accumulate intracellularly. High concentrations of β‐lactam antibiotics (5 × MGIC) were bacteriostatic not bactericidal and this may be related to an apparent deficiency in the endogenous autolytic enzymes of strain MR‐1. Studies of the penicillin‐binding proteins after growth in the presence of methicillin suggest that one of these proteins remains resistant to very high concentrations of the antibiotic. We propose that this protein acts as the primary transpeptidase responsible for the incorporation of newly synthesised peptidoglycan into the growing wall.

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Section: Discussionmentioning

confidence: 91%

mentioning

confidence: 99%

Synthesis of Peptidoglycan in vivo in Methicillin‐Resistant Staphylococcus aureus

Wyke

Ward²,

Hayes

1982

European Journal of Biochemistry

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“…Most of the antibiotic resistance genes of Staphylococcus aureus are located in plasmids (18). Many kinds of antibiotic resistance plasmids of Staphylococcus aureus have been studied in the field of molecular genetics (19,20).…”

Section: Discussionmentioning

confidence: 99%

CORRELATIONS BETWEEN COAGULASE TYPES AND ANTIBIOGRAMS OF STAPHYLOCOCCUS AUREUS FROM BACTERIAL SKIN INFECTIONS

Dekio

Onimura

1982

The Journal of Dermatology

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We investigated coagulase types by a simplified method for coagulase typing and antibiotic sensitivities by a disk diffusion method in 557 strains of Staphylococcus aureus isolated from lesions of vatious bacterial skin infections. Every strain investigated fell into only one of eight coagulase types by coagulase typing, and obvious correlations were seen between the coagulase types and the antibiograms. It was suggested that compatibility-incompatibility relationships might be present between genes of coagulases of different coagulase types and antibiotic resistance plasmids.

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“…They collected evidence that the high-resistance group was of the ribosomal-chromosomal type whereas the low-resistance group was plasmid-borne in some strains. Attempts to transduce the plasmid-borne SM-resistance failed and there is no indication for transfers to occlir under clinical conditions (LACEY and RICHMOND, 1974;LACEY, 1975 IRWIN, 1974), while only a few reports provide substantial evidence of synergistic effects of the same combination against staphylococci (HANCOCK, 1960;BOROWSKI, 1973). CANTOR and PALOCHAK (1975) reported on the synergism in vitro of the 1 : 1 combination of procaine-PEN and DHSM2 with mastitis pathogens including a strain of Staph.…”

Section: Introductionmentioning

confidence: 99%

A Quantitative in vitro Evaluation of the Combined Action of Benzylpenicillin and Dihydrostreptomycin on Staphylococci Isolated from the Bovine Udder with Special Regard to Synergistic Activities

Rosselet

Schluep

Knüsel

1977

Zentralblatt für Veterinärmedizin Reihe B

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Summary 206 strains of Staph, aureus isolated from bovine mastitic milks were analysed for their susceptibility to benzylpenicillin (PEN) and dihydrostreptomycin (DHSM). On the base of MIC‐determinations 43% of the strains turned out to be PEN‐resistant and 33% DHSM‐resistant. 97% of the PEN‐resistant strains were penicillinase producers. The influence of the inoculum size on the PEN‐susceptibility of the PEN‐resistant group was very pronounced. On the other hand, the response of the strains to DHSM was hardly influenced by the inoculum size. The comparison of cumulative percentages of inhibition of the antibiotics used singly and combined and the analysis of the fractional inhibitory concentrations led to the conclusion of a significant synergistic effect of the combination. A synergistic effect of the combination was established also with the group of staphylococci resistant to both PEN and DHSM. The induction of penicillinase by PEN was examined on two PEN‐resistant strains. The beta‐lactamase production was reduced to one tenth by the concomitant influence of DHSM (PEN 100 I. U./ml, DHSM 100 mcg/ml). In an agar‐diffusion assay, one tenth MIC of DHSM increased the activity of PEN 9–14 fold while PEN potentiated the efficacy of DHSM by a factor 3–7. These data are discussed with respect to the number of staphylococci that are likely to occur in the bovine udder in cases of chronic mastitis, and with regard to the concentrations of the drugs present in the mammary glands of cows treated at drying‐off. The results give substantial evidence to explain the excellent therapeutic effect obtained against staphylococcal mastitis by combinations of PEN and DHSM at high dosage rates. Zusammenfassung Quantitative Erfassung der kombinierten in‐vitro Aktivitäten von Benzylpenicillin und Dihydrostreptomycin auf bovine Euter‐Staphylokokken unter besonderer Berücksichtigung von synergistischen Wirkungen 206 aus Milchproben isolierte Staph. aureus‐Stämme wurden auf ihre Empfindlichkeit gegen Benzylpenicillin (PEN) und Dihydrostreptomycin (DHSM) untersucht. Bei einer angenommenen Grenzkonzentration von 4.1 I. E./ml resp. 37 mcg/ml wurden 43% der Stämme als PEN‐resistent und 33% als DHSM‐resistent klassiert. 97% der PEN‐resistenten Stämme produzierten Penicillinase. Die PEN‐Empfindlichkeit der PEN‐resistenten Staphylokokken war stark inokulumabhängig. In viel geringerem Ausmaß wurde die DHSM‐Empfindlichkeit der DHSM‐resistenten Stämme durch die Größe des Inokulums beeinflußt. Aus dem Vergleich der kumulativen Prozentsätze der Wachstumshemmung durch die Antibiotika allein und in Kombination sowie aus einer Analyse der fraktionierten Hemmkonzentrationen (FIC) ergaben sich eindeutige Anhaltspunkte für eine signifikante synergistische Wirkung der Kombination PEN/DHSM. Diese synergistische Wirkung kam auch bei PEN‐ und DHSM‐resistenten Stämmen zum Ausdruck. An zwei Stämmen wurde die Penicillinase‐Induktion durch PEN überprüft. Es zeigte sich, daß die Beta‐Laktamase‐Produktion durch den Einfluß von DHSM auf einen Zehntel der durch PEN ...

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Antibiotic resistance plasmids of Staphylococcus aureus and their clinical importance.

Cited by 115 publications

References 149 publications

Synthesis of Peptidoglycan in vivo in Methicillin‐Resistant Staphylococcus aureus

Synthesis of Peptidoglycan in vivo in Methicillin‐Resistant Staphylococcus aureus

CORRELATIONS BETWEEN COAGULASE TYPES AND ANTIBIOGRAMS OF STAPHYLOCOCCUS AUREUS FROM BACTERIAL SKIN INFECTIONS

A Quantitative in vitro Evaluation of the Combined Action of Benzylpenicillin and Dihydrostreptomycin on Staphylococci Isolated from the Bovine Udder with Special Regard to Synergistic Activities

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