Isolation and characterization of vancomycin-tolerant Streptococcus pneumoniae from the cerebrospinal fluid of a patient who developed recrudescent meningitis

The emergence of tolerance to vancomycin has recently been reported in Stre ptococcus pneumoniae, the most common cause of bacterial meningitis. A vanc omycin- and cephalosporin-tolerant strain of S, pneumoniae, the Tupelo stra in, was isolated from the cerebrospinal fluid of a patient who then develop ed recrudescence of meningitis despite treatment with vancomycin and a thir d-generation cephalosporin. The Tupelo strain evidenced no lysis in the exp onential or stationary phase of growth when exposed to vancomycin and only minimal loss of viability. Further characterization revealed normal autolys in expression, localization, and triggering by detergents, indicating that the defect leading to tolerance in the Tupelo strain is in the control path way for triggering of autolysis, Because tolerance is a precursor phenotype to resistance and may lead to clinical failure of antibiotic therapy, thes e observations may have important implications for vancomycin use in infect ions caused by S. pneumoniae.