Susceptibility of group B streptococci to 16 beta-lactam antibiotics, including new penicillin and cephalosporin derivatives

Jacobs, M. R.; Kelly, Florene C.; Speck, William T.

doi:10.1128/aac.22.5.897

Cited by 26 publications

(12 citation statements)

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“…We ascertained that our results were reproducible by means of the kill kinetic method. The results of the susceptibility studies showed that the ,B-lactam agents tested displayed good activity in vitro, although this was less than that noted by the majority of investigators (3,4,6,15,21). We found two strains with intermediate susceptibility to penicillin and eight with intermediate susceptibility to ampicillin.…”

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confidence: 68%

“…The incidence and clinical significance of penicillin tolerance in GBS infections have not been established. The different methods used by researchers may explain the discrepant results observed in published studies; the occurrence of penicillin tolerance in clinical isolates of GBS varies widely and ranges from 0% (15) to 4% (18,33), 13% (8), 30% (1), and 87% (19). Tolerance is best detected by quantitative killing curve procedures.…”

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confidence: 89%

“…Despite consistent susceptibility of the majority of GBS to penicillin and ampicillin (3,4,6,15,21,27), there are several reports of poor clinical responses to appropriate therapy and of relapses in GBS infections in newborn infants and adults (2,11,12,38). These failures have led to changes in the treatment of GBS infections: increase in penicillin dosages or combination with an aminoglycoside has been recommended for treatment of serious GBS infections in adults and neonates (23).…”

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confidence: 99%

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Antibiotic resistance and penicillin tolerance in clinical isolates of group B streptococci

Betriú

Gómez

Sánchez

et al. 1994

Antimicrob Agents Chemother

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The aim of this study was to determine the susceptibility patterns of 100 group B streptococcal strains isolated in our hospital and to ascertain tolerance to penicillin by determining quantitative killing curves. We found two strains with intermediate susceptibility to penicillin and eight strains to ampicillin. Seventeen isolates were tolerant to penicillin, with bacterial counts decreasing 2 to 3 log during the first 8 h but still above 10(2) CFU/ml after 24 h. The kinetic study shows that penicillin tolerance is not rare among group B streptococci isolated in our hospital.

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confidence: 68%

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confidence: 89%

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confidence: 99%

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Antibiotic resistance and penicillin tolerance in clinical isolates of group B streptococci

Betriú

Gómez

Sánchez

et al. 1994

Antimicrob Agents Chemother

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“…DISCUSSION The details of the methods used in broth dilution susceptibility testing of group B streptocqcfi have varied widely, as exemplified by the choice of niodium. In the reports cited in this paper, Todd-Hewitt b oth has been used by four groups (2, 12, 23, 24), Mueller-17tnton broth by three groups (1,4,13,(15)(16)(17)20), Trypticase soy broth (BBL Microbiology Systems) by two groups (9,18), and Schaedler broth (19) and the Sensititre medium (3) by one group each. Our choice of Todd-Hewitt broth was conservative, and it remains to be seen whether any of our findings were medium dependent.…”

Section: Resultsmentioning

confidence: 99%

Reverse inoculum effect in bactericidal activity and other variables affecting killing of group B streptococci by penicillin

Jokipii¹,

Brander²,

Jokipii³

1985

Antimicrob Agents Chemother

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Variables of the effect of penicillin G on the numbers of viable group B streptococci in broth cultures were studied. One-fourth of the MIC was the lowest concentration that reduced the viable count compared with antibiotic-free controls. The rate of killing increased with the concentration of penicillin up to 4x MIC, but no further. During the first 2 or 3 h, the bactericidal activity was more rapid than later on. The MIC and supraoptimal concentrations of penicillin killed an inoculum of 10' organisms more rapidly than an inoculum of 104 organisms. The MIC was not inoculum dependent. The reverse inoculum effect was revealed by the killing curves but not by the MBC. There were reproducible differences among strains as to the rate of killing by penicillin; these did not correlate with the rate of multiplication, which also varied among strains. Among the 11 strains tested, there were no tolerant ones.Huge numbers of antimicrobial susceptibility tests are performed daily to predict therapeutic efficacy. Such predictive value is known in only few instances (10). Most tests detect growth inhibitory activity, and dissociation of in vitro and in vivo results is to be expected when bactericidal activity is needed for cure, as is believed to be the case with infections of immunocompromised patients or with infections, like endocarditis, of immunologically privileged sites. Group B streptococci are susceptible to penicillin in the conventional sense, but neonatal infections have turned out to be difficult to treat, and failures have been ascribed to penicillin tolerance, i.e., relative resistance to the bactericidal effect (4, 23).The description of bactericidal activity has remained a problem. The most widely used parameter is the MBC, and we have characterized several variables of the effect of penicillin on the numbers of viable group B streptococci to see to what extent the MBC reveals all relevant information about bactericidal activity. The model combination was chosen, because it has been studied extensively before, because it is one of the combinations with which phenomena like paradoxically reduced killing at high antibiotic concentrations (7) and antibiotic tolerance have been described, and because it has been associated with therapeutic failures. MATERIALS AND METHODSBacteria. Group B streptococci were isolated from clinical specimens from various male and female genital, throat, nose, ear, and skin infections as the predominant probable pathogen. They were identified by three presumptive tests, hippurate hydrolysis, cAMP reaction, and pigment production, as well as serologically, as described earlier (14). Thirty-five isolates were selected randomly for these studies from a collection maintained lyophilized and by serial passage on blood agar plates.Inoculum. In preliminary studies of 18-to 21-h growth curves, supplementing Todd-Hewitt broth (BBL Microbiology Systems, Cockeysville, Md.) with 0.8% glucose reduced the growth of group B streptococci, and 10% horse serum had essentially no effect. Thus, plai...

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“…Among above mentioned antibiotics penicillin is the drug of choice next to cefazolin. However, it also have certain limitations such as high minimum inhibitory concentration (MIC), a factor associated with high level of bacteremia and more concentration of microbes in tissue, especially in cerebrospinal fluid [7,8]. Therefore, some alternative treatment strategies are needed to overcome these lacunas against β-hemolytic strain of gr.…”

Section: Introductionmentioning

confidence: 99%

Effect of Biofield Energy Treatment on Streptococcus group B: A Postpartum Pathogen

Trivedi¹,

Branton²,

Trivedi³

et al. 2015

J Microb Biochem Technol

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Streptococcus agalactiae group B (S. agalactiae gr. B) is widespread in nature mainly causes bacterial septicemia and neonatal meningitis. The current study was attempted to investigate the effect of biofield treatment on S. agalactiae gr. B with respect of antimicrobial sensitivity, biochemical reactions and bio typing. S. agalactiae gr. B strain was used in this experiment bearing the American Type Culture Collection (ATCC 12386) number and stored according to the recommended storage protocol. The revived and lyophilized state of ATCC strains of S. agalactiae gr. B were selected for the study. Gr. I was considered as control. Both revived (Group; Gr. II) and lyophilized (Gr. III) strains of S. agalactiae gr. B were subjected to Mr. Trivedi's biofield treatment. Gr. II was assessed on day 5 and day 10 while Gr. III on day 10 with respect to the control (Gr. I) using MicroScan Walk-Away ® system. Although biofield treatment did not show any change with respect to susceptibility pattern. However the minimum inhibitory concentration of S. agalactiae gr. B showed significant (70.37%) alteration, out of twenty-seven tested antimicrobials, among which in Gr. II i.e. 62.96% on day 5 and 66.67% on day 10 while no alteration was found in lyophilized group (Gr. III) as compared to the control. Moreover, the improvement of MIC value of norfloxacin was observed by two-fold (8 to ≤4 µg/mL) in Gr. II on day 10 after biofield energy treatment as compared to the control. It was observed that overall 48.28% biochemical reactions, out of twenty-nine were altered in Gr. II with respect to the control. Moreover, biotype numbers were changed in Gr. II on day 5 (777777615) and on day 10 (757677405) as compared to the control (237147047). The results suggest that biofield treatment has significant impact on S. agalactiae gr. B in revived treated cells (Gr. II) with respect to MIC values, biochemical reactions pattern and biotype number.

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Susceptibility of group B streptococci to 16 beta-lactam antibiotics, including new penicillin and cephalosporin derivatives

Cited by 26 publications

References 12 publications

Antibiotic resistance and penicillin tolerance in clinical isolates of group B streptococci

Antibiotic resistance and penicillin tolerance in clinical isolates of group B streptococci

Reverse inoculum effect in bactericidal activity and other variables affecting killing of group B streptococci by penicillin

Effect of Biofield Energy Treatment on Streptococcus group B: A Postpartum Pathogen

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