EVOLVING CLINICAL PROBLEMS WITH STREPTOCOCCUS-PNEUMONIAE - INCREASINGRESISTANCE TO ANTIMICROBIAL AGENTS, AND FAILURE OF TRADITIONAL OPTOCHIN IDENTIFICATION IN CHICAGO, ILLINOIS, BETWEEN 1993 AND 1996

Infections due to multidrug-resistant pneumococci are a growing concer n. Through December 1995, over 85% of isolates recovered from our pati ents in Chicago, Illinois, were fully susceptible to penicillin, and o nly a rare resistant strain was recovered from brood or cerebrospinal fluid (CSF). In December 1995, we began to observe bloodstream infecti ons due to Streptococcus pneumoniae with penicillin MICs that represen ted either intermediate or full resistance to penicillin. S. pneumonia e isolated between January 1, 1993, and December 31, 1996, were tested against II different antimicrobial agents. There were 158 from blood or CSF, and 303 from other (primarily respiratory) sources. During 199 6, 46% of our total S. pneumoniae isolates were no longer fully suscep tible to penicillin, representing a threefold increase from the previo us year's experience. In isolates from blood and CSF, move than 90% of strains had been fully susceptible to penicillin through 1995, but si nce the start of 1996, 29% of our invasive isolates were no longer ful ly susceptible to penicillin. During 1996, vancomycin was the only cur rently approved agent that was active against all recovered isolates. We also noted two isolates during 1996 where optochin testing did not accurately identify strains as S. pneumoniae. A major problem with mul tidrug resistant S. pneumoniae causing both respiratory and invasive d iseases appears to have now reached the Chicago area. Laboratories nee d to be aware of a continued increase in anti microbial agent resistan ce exhibited by this pathogen, as well as potential difficulties that can be encountered using traditional laboratory identification methods . (C) 1997 Elsevier Science Inc.