Variation between penicillin-tolerant and penicillin-sensitive states in Streptococcus faecium ATCC9790

Daneo-Moore, L

doi:10.1016/0378-1097(85)90333-7

Cited by 2 publications

(4 citation statements)

References 9 publications

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“…A problem that might complicate the determination of tolerance is that it is not always a stable property. In enterococci (14), Streptococcus pyogenes (15) and Staphylococcus aureus (3,16) tolerance may be lost partially or completely after storage, even at -70°C. On the other hand, it has been shown for Staphylococcus aureus (17,18), Streptococcus sanguis (8) and Streptococcus pyogenes (18) that tolerance could emerge in nontolerant strains after repeated exposure to [~-lactam antibiotics in vitro.…”

Section: In Vitro Development and Stability Of Tolerance To Cloxacillmentioning

confidence: 99%

In vitro development and stability of tolerance to cloxacillin and vancomycin inStaphylococcus aureus

Voorn

Thompson

Goessens

et al. 1994

Eur. J. Clin. Microbiol. Infect. Dis.

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The stability of tolerance of Staphylococcus aureus during subculturing at 37 degrees C and development of this property after repeated exposure to cloxacillin or vancomycin were investigated in vitro. Four of five tolerant strains lost this property during repeated subculturing at 37 degrees C for 50 days. Conversely, tolerance emerged in two of four nontolerant strains after repeated cycles of exposure to 25 micrograms of cloxacillin/ml or 10 micrograms of vancomycin/ml alternating with growth in antibiotic-free medium. Previous in vivo exposure to cloxacillin did not enhance the development of tolerance in vitro. MICs of both cloxacillin and vancomycin did not change significantly during this procedure. Whether the conversion of nontolerant strains to the tolerant state can also occur during antibiotic exposure in treatment of patients remains to be determined.

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Section: In Vitro Development and Stability Of Tolerance To Cloxacillmentioning

confidence: 99%

In vitro development and stability of tolerance to cloxacillin and vancomycin inStaphylococcus aureus

Voorn

Thompson

Goessens

et al. 1994

Eur. J. Clin. Microbiol. Infect. Dis.

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“…For any one antibiotic, lysis was not necessarily initiated near the MIC, which was determined at a much lower inoculum and after 24 h of incubation. We have shown previously that the MICs of each of the above-mentioned antibiotics for S and T derivatives are essentially indistinguishable but that the MBCs are 16-to 100-fold higher for T derivatives than for S derivatives (8).…”

mentioning

confidence: 89%

“…We recently reported that Streptococcus faecium ATCC 9790 was tolerant (T) of the lethal action of penicillin G as well as of that of bacitracin, vancomycin, and D-cyclOserine (8). Single-cell-colony isolates of ATCC 9790 exhibited an approximate 5% loss of tolerance.…”

mentioning

confidence: 99%

“…A lineage analysis over many transfers indicated that the change from tolerance to susceptibility was reversible and that susceptible (S) derivatives became tolerant at the same 5% frequency (8). The T and S cultures studied differed from each other in the extent of survival after exposure to penicillin G or to several other inhibitors of cell wall synthesis and also in the rate of penicillin-induced lysis (8). At concentrations that produced detectable lysis of S cultures, penicillin induced lysis of T cultures at a barely detectable rate.…”

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confidence: 99%

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Penicillin tolerance in Streptococcus faecium ATCC 9790

Said

Fletcher

Volpe

et al. 1987

Antimicrob Agents Chemother

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Tolerant strains of Streptococcus faecium had higher levels of muramidase 2 and lower levels of trypsinactivable muramidase 1 than did susceptible strains. Susceptible strains lysed faster than did tolerant strains in buffer and at some antibiotic concentrations. The addition of Triton X-100 produced equal lysis rates for susceptible and tolerant cultures.We recently reported that Streptococcus faecium ATCC 9790 was tolerant (T) of the lethal action of penicillin G as well as of that of bacitracin, vancomycin, and D-cyclOserine (8). Single-cell-colony isolates of ATCC 9790 exhibited an approximate 5% loss of tolerance. A lineage analysis over many transfers indicated that the change from tolerance to susceptibility was reversible and that susceptible (S) derivatives became tolerant at the same 5% frequency (8). The T and S cultures studied differed from each other in the extent of survival after exposure to penicillin G or to several other inhibitors of cell wall synthesis and also in the rate of penicillin-induced lysis (8). At concentrations that produced detectable lysis of S cultures, penicillin induced lysis of T cultures at a barely detectable rate. The availability of strains with a high rate of change between tolerant and susceptible states permitted an analysis of the physiological basis for tolerance. S and T derivatives recloned three times were used in this study.Cultures were grown in Todd-Hewitt medium supplemented with 0.15% glucose, and antibiotics were added in the exponential phase of growth when the cultures contained about 108 cells per ml. All glassware was acid washed. For autolysis assay cells were harvested as described previously (14) by filtration on 0.65-p.m-pore membrane filters (Millipore Corp., Bedford, Mass.), washed twice with about 5 ml (each time) of ice-cold distilled water, and suspended in 0.3 M potassium phosphate buffer (pH 6.8) (12). Autolysis rates (h-') were determined from the pseudo first-order reaction rate as described previously (14). Table 1 shows the rates of lysis of exponential cultures exposed to various antibiotics. In the case of penicillin G or D-cycloserine, S cultures lysed faster than did T cultures at antibiotic concentrations below the MIC but not at or above the MIC. For bacitracin, S cultures lysed faster than did T cultures above the MIC. Finally, for vancomycin, rates of lysis were not very different for S and T cultures examined both above and below the MIC. The data shown in Table 1 indicate that in terms of cell lysis, T strains were only relatively tolerant, since high enough concentrations of each antibiotic resulted in lysis. For any one antibiotic, lysis was not necessarily initiated near the MIC, which was determined at a much lower inoculum and after 24 h of incubation. We have shown previously that the MICs of each of the above-mentioned antibiotics for S and T derivatives are essentially indistinguishable but that the MBCs are 16-to 100-fold higher for T derivatives than for S derivatives (8).* Corresponding author. t Present address: CE...

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Variation between penicillin-tolerant and penicillin-sensitive states in Streptococcus faecium ATCC9790

Cited by 2 publications

References 9 publications

In vitro development and stability of tolerance to cloxacillin and vancomycin inStaphylococcus aureus

In vitro development and stability of tolerance to cloxacillin and vancomycin inStaphylococcus aureus

Penicillin tolerance in Streptococcus faecium ATCC 9790

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