Identification of Streptococcus pneumoniae resistant to optochin / 中华检验医学杂志

ABSTRACT

Objective Correctly identify Streptococcus pneumoniae resistant to optochin and other alpha hemolytic streptococcus susceptible to optochin.Methods Optochin susceptibility test, bile resolution test, latex agglutination test as well as some biochemical methods (VITEKCC4-GPI identifying cards,API-Strept identifying bar, VITEK TWO-GPC identifying cards) were applied.Results It was observed that 2 strains(0.3%)of Streptococcus pneumoniae out of 630 were resistant to optochin and 31strains of Streptococci, classfied as alpha hemolytic streptococci, susceptible to optochin, including 13 of S. mitis, 6 of S.oralis, 6 of S. twin, 3 of S. acidominimus, 2 of S.intermedius and 1 of S. constellatus. The inhibition zone of these alpha hemolytic streptococci susceptible sensitive to optochin was within the range of 14-17mm in diameter, in not 20 mm or more than 20 mm, compared with the inhibition zone of most strains of S.pneumoniae. Most of these alpha hemolytic streptococci (93.5%) susceptible to optochin showed highly resistance to benzoxazolecillin,to which most Streptococci (94%) showed sensitivity . Conclusion S.pneumoniae can be effectively identified by bile resolution test and latex agglutination test because of its high specificity with credible test results. API-Strept identifying bar and VITEK TWO-GPC identifying cards can be applied to identify S. pneumoniae resistant to optochin.