Journal Article

Clinical Isolates of <i>Streptococcus pneumoniae</i> That Exhibit Tolerance of Vancomycin

Birgitta Henriques Normark, Rodger Novak, Åke Örtqvist, Gunilla Källenius, Elaine Tuomanen and Staffan Normark

in Clinical Infectious Diseases

Published on behalf of Infectious Diseases Society of America

Volume 32, issue 4, pages 552-558
Published in print February 2001 | ISSN: 1058-4838
Published online February 2001 | e-ISSN: 1537-6591 | DOI:
Clinical Isolates of Streptococcus pneumoniae That Exhibit Tolerance of Vancomycin

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The ability of Streptococcus pneumoniae to escape lysis and killing by vancomycin, a property termed “tolerance,” has recently been noted in a laboratory strain of the species. Vancomycin tolerance in clinical isolates represents a potential new health risk. We determined the prevalence of vancomycin and penicillin tolerance among 116 clinical isolates of pneumococci by monitoring lysis and viability after exposure to the respective antibiotic for 4 hours. Eight percent of the strains were tolerant to penicillin and 3% were tolerant to vancomycin. The 3 vancomycin-tolerant isolates also had a high ratio of minimum bactericidal concentration to minimum inhibitory concentration, in contrast to nontolerant strains. They were of serotype 9V and had reduced susceptibility to penicillin. Only 1 was also tolerant to penicillin. Growth rate and ability to divide were not affected in the 3 vancomycin-tolerant strains, and they all lysed with deoxycholate, which indicates autolysin production. Vancomycin tolerance among clinical isolates of pneumococci will necessitate tracking to determine the magnitude of the evolving health risk, since tolerance may contribute to treatment failure (in particular, cases of meningitis, in which bactericidal activity is critical for eradication) and since it may also be a favored background for acquisition of resistance of vancomycin.

Journal Article.  4157 words.  Illustrated.

Subjects: Infectious Diseases ; Immunology ; Public Health and Epidemiology ; Microbiology

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