Recurrence of group B streptococcal infection

Broughton, Daniel D.; Mitchell, Wendy G.; Grossman, Moses; Hadley, W K; Cohen, Martin S.

doi:10.1016/s0022-3476(76)80441-6

Cited by 56 publications

(22 citation statements)

References 5 publications

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“…This alternative has not been generally considered for group B streptococcal meningitis, and the regimen most often used has been a combination of penicillin and an aminoglycoside (4,15 (11).…”

Section: Resultsmentioning

confidence: 99%

“…These differences may be responsible for the higher clinical failure rates in patients with group B streptococcal infections who are treated with penicillin. These failures have subsequently led to changes in the therapy regimens required to effect cures in group B streptococcal infections (4,11,15 (1) to obtain solutions at 10 times each of the desired final concentrations. One part of the 1Ox stock solution was added to nine parts of broth to obtain each desired concentration and dispensed in 0.1-ml volumes into each well of microdilution trays with the MIC 2000 dispenser (Dynatech Laboratories, Inc., Alexandria, Va.).…”

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confidence: 99%

See 1 more Smart Citation

Synergism, killing kinetics, and antimicrobial susceptibility of group A and B streptococci

Baker¹,

Thornsberry²,

Facklam³

1981

Antimicrob Agents Chemother

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Synergism, killing kinetics, and antimicrobial susceptibility of group A and B streptococci

Baker¹,

Thornsberry²,

Facklam³

1981

Antimicrob Agents Chemother

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“…Although group B streptococci appear to be consistently susceptible to penicillin (2, 3), unsatisfactory results have often followed penicillin treatment of septic infants, including reoccurrence of disease after apparently successful therapy (4,13,14), persistence of viable streptococci in the cerebrospinal fluid after several days of treatment (6,7), and frank bacteriological and clinical relapse of meningitis during therapy (5). The reasons for these poor responses are undoubtedly complex, but one proposed explanation is penicillin tolerance by Streptococcus, defined as delayed or diminished killing by growthinhibiting concentrations of the antibiotic.…”

Section: Discussionmentioning

confidence: 99%

Importance of Medium in Demonstrating Penicillin Tolerance by Group B Streptococci

Kim

Yoshimori

Imagawa

et al. 1979

Antimicrob Agents Chemother

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A total of 30 clinical isolates of group B streptococci were studied for penicillin tolerance in vitro. Minimal inhibitory and bactericidal concentrations of penicillin were determined simultaneously in three test media which have been used for group B streptococci, tryptose phosphate, Muelier-Hinton, and Todd-Hewitt broths, using a logarithmic-phase inoculum of 105 colony-forming units per ml.Minimal inhibitory concentrations in the three media did not differ significantly. However, minimal bactericidal concentrations were significantly higher in tryptose phosphate broth (mean, 1.04 ,ug/ml) than in Mueller-Hinton broth (0.22 ,ug/ ml) or Todd-Hewitt broth (0.15 ,ug/ml). Similarly, ratios of minimal bactericidal to minimal inhibitory concentrations were significantly greater in tryptose phosphate broth than in Mueller-Hinton or Todd-Hewitt broth. After incubation in tryptose phosphate broth for an additional 24 h, the minimal bactericidal concentration consistently fell to levels which were only twice or equal to the minimal inhibitory concentration. This study illustrates the importance of the medium in the demonstration of penicillin tolerance and of controlling laboratory variables in the susceptibility testing of group B streptococci with penicillin.The group B streptococci are recognized as a major cause of serious neonatal infections. Poor results with penicillin therapy, despite consistent susceptibility to this group of antimicrobial agents, have prompted studies of the in vitro susceptibility ofthese streptococci to antibiotics. There are several reports of penicillin tolerance (minimal bactericidal concentration [MBC] significantly higher than minimal inhibitory concentration [MIC]), but the methodology has varied from study to study. In this report, we describe the importance of the test medium in the demonstration of this phenomenon. MATERIALS AND METHODSA total of 30 strains of group B streptococci were obtained from the clinical microbiology laboratory at Harbor/UCLA Medical Center, 12 were fsh isolates, and 18 were previous isolates which had been stored at -70°C in 10% sterile skimmed milk (Difco Laboratories, Detroit, Mich.) for up to 12 months. Each strain was from a different patient. They were identified as group B streptococci by the method of Lancefield (8) with sera provided by the Center for Disease Control, Atlanta, Ga. Twelve isolates were from throat cultures, five were from cervical swabs, two were from cerebrospinal fluid, two were from umbilical cultures, and one each was from blood, gastric aspirate, urine, stool, conjunctiva, nose, external ear, endometrium, and scalp lesion.Five colonies were subcultured from sheep blood agar to 10 ml of tryptose phosphate (TP) broth (Difco), which was incubated at 37°C for 6 h. This was diluted in fresh TP broth to a concentration of approximately 105 colony-forming units per ml, as determined by measuring the light scattering of the suspension with a Coleman model 9 nephocolorimeter (Coleman Instruments, Oak Brook, Ill.). Colony counts performe...

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“…From the findings described here, one might expect that group B streptococci colonizing such sites would be relatively resistant to the bactericidal effect of penicillin, and this phenomenon may contribute to the problems encountered during attempts to prophylactically eradicate colonizing group B streptococci (13,23) and also to treatment failures described in "early onset" neonatal infections (7,10,18,19,25,26). The relatively low pH of vaginal secretions has already been invoked as a possible factor contributing to the ineffectiveness of erythromycin treatment in vaginitis caused by Haemophilus vaginalis infection (11).…”

Section: Methodsmentioning

confidence: 83%

“…Penicillin has been the chemotherapeutic agent of choice in treating these infections (5), and prophylactic use of penicillin has been also suggested for the elimination of the bacteria from parturient women (13). Nevertheless, there have been numerous reports of treatment failures (7,10,18,19,25,26), and difficulties have been encountered in eradicating group B streptococci colonizing mucosal surfaces in both infants and adults (13,19,23). These failures have sometimes been attributed to the relatively high minimal inhibitory concentrations (MICs) of penicillin (1) and to the slow bactericidal effect of this antibiotic (21) in comparison with the highly penicillin-susceptible group A streptococci.…”

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confidence: 99%

pH-dependent penicillin tolerance of group B streptococci

Horne¹,

Tomasz²

1981

Antimicrob Agents Chemother

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Group B streptococci lose viability without apparent lysis during treatment with beta-lactam antibiotics and vancomycin. Rapid loss of viability was observed in early-exponential-phase cultures. Cultures in the mid-exponential growth phase exhibited various degrees of resistance to the bactericidal effect of the antibiotics, whereas their susceptibilities to the growth-inhibitory effect remained unchanged. This growth-phase-dependent tolerance was caused by the gradual increase in acidity of the cultures as the cell concentration increased. Retitration of the pH to neutrality made the formerly tolerant bacteria again fully susceptible to the killing effect of penicillin. Conversely, lowering the pH value of the medium resulted in antibiotic tolerance throughout culture growth. The penicillin-binding proteins of whole bacteria and their labeling pattern were found to be independent of culture pH. It is suggested that the mechanism of Ph-dependent tolerance is indirect and may be mediated by an autolysin. The tolerance of group B streptococci for penicillin could be clinically relevant in view of the relatively low pH values known to prevail in the natural host environments colonized by these bacteria.

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Recurrence of group B streptococcal infection

Cited by 56 publications

References 5 publications

Synergism, killing kinetics, and antimicrobial susceptibility of group A and B streptococci

Synergism, killing kinetics, and antimicrobial susceptibility of group A and B streptococci

Importance of Medium in Demonstrating Penicillin Tolerance by Group B Streptococci

pH-dependent penicillin tolerance of group B streptococci

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