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. 1979 Aug;16(2):214–216. doi: 10.1128/aac.16.2.214

Importance of Medium in Demonstrating Penicillin Tolerance by Group B Streptococci

Kwang Sik Kim 1, Robert N Yoshimori 2, David T Imagawa 1,3, Bascom F Anthony 1
PMCID: PMC352824  PMID: 384895

Abstract

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, Mueller-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 μg/ml) than in Mueller-Hinton broth (0.22 μg/ml) or Todd-Hewitt broth (0.15 μg/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.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Allen J. L., Sprunt K. Discrepancy between minimum inhibitory and minimum bactericidal concentrations of penicillin for group A and group B beta-hemolytic streptococci. J Pediatr. 1978 Jul;93(1):69–71. doi: 10.1016/s0022-3476(78)80603-9. [DOI] [PubMed] [Google Scholar]
  2. Anthony B. F., Concepcion N. F. Group B streptococcus in a general hospital. J Infect Dis. 1975 Nov;132(5):561–567. doi: 10.1093/infdis/132.5.561. [DOI] [PubMed] [Google Scholar]
  3. Baker C. J., Webb B. J., Barrett F. F. Antimicrobial susceptibility of group B streptococci isolated from a variety of clinical sources. Antimicrob Agents Chemother. 1976 Jul;10(1):128–131. doi: 10.1128/aac.10.1.128. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Broughton D. D., Mitchell W. G., Grossman M., Hadley W. K., Cohen M. S. Recurrence of group B streptococcal infection. J Pediatr. 1976 Aug;89(2):182–185. doi: 10.1016/s0022-3476(76)80441-6. [DOI] [PubMed] [Google Scholar]
  5. Dorand R. D., Adams G. Relapse during penicillin treatment of group B streptococcal meningitis. J Pediatr. 1976 Aug;89(2):188–190. doi: 10.1016/s0022-3476(76)80444-1. [DOI] [PubMed] [Google Scholar]
  6. Edwards K., Ferrieri P., Thompson T. R., Davis A. T. Group B streptococcal meningitis: delayed response to treatment. Childs Brain. 1977;3(6):343–351. doi: 10.1159/000119685. [DOI] [PubMed] [Google Scholar]
  7. Feldman W. E. Concentrations of bacteria in cerebrospinal fluid of patients with bacterial meningitis. J Pediatr. 1976 Apr;88(4 Pt 1):549–552. doi: 10.1016/s0022-3476(76)80003-0. [DOI] [PubMed] [Google Scholar]
  8. Overturf G. D., Horowitz M., Wilkins J., Leedom J., Steinberg E. Bactericidal studies of penicillin-gentamicin combinations against group B streptococci. J Antibiot (Tokyo) 1977 Jun;30(6):513–518. doi: 10.7164/antibiotics.30.513. [DOI] [PubMed] [Google Scholar]
  9. Sabath L. D., Wheeler N., Laverdiere M., Blazevic D., Wilkinson B. J. A new type of penicillin resistance of Staphylococcus aureus. Lancet. 1977 Feb 26;1(8009):443–447. doi: 10.1016/s0140-6736(77)91941-9. [DOI] [PubMed] [Google Scholar]
  10. Schauf V., Deveikis A., Riff L., Serota A. Antibiotic-killing kinetics of group B streptococci. J Pediatr. 1976 Aug;89(2):194–198. doi: 10.1016/s0022-3476(76)80446-5. [DOI] [PubMed] [Google Scholar]
  11. Tomasz A., Albino A., Zanati E. Multiple antibiotic resistance in a bacterium with suppressed autolytic system. Nature. 1970 Jul 11;227(5254):138–140. doi: 10.1038/227138a0. [DOI] [PubMed] [Google Scholar]
  12. Truog W. E., Davis R. F., Ray C. G. Recurrence of group B streptococcal infection. J Pediatr. 1976 Aug;89(2):185–186. doi: 10.1016/s0022-3476(76)80442-8. [DOI] [PubMed] [Google Scholar]
  13. Walker S. H., Santos A. Q., Quintero B. A. Recurrence of group B III streptococcal meningitis. J Pediatr. 1976 Aug;89(2):187–188. doi: 10.1016/s0022-3476(76)80443-x. [DOI] [PubMed] [Google Scholar]

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