[An epidemiological study of penicillin-resistant Streptococcus pneumoniae in Japan]

In order to investigate penicillin resistance (Pcr) in Streptococcus pneumoniae from clinical sources in Japan, a total 1,127 strains of S. pneumoniae was collected at random from 36 institutions participating to "Working group for Pcr S. pneumoniae" around the country in 1993-1994. These strains were isolated more frequently from sputum (38.2%), throat (31.4%), nasal discharge (16.4%), and otorrhea (5.7%). A small number of isolates from blood (19 strains; 1.8%), cerebrospinal fluid (11 strains; 1.0%), and pleural fluid (2 strains; 0.2%) were included respectively. Patients from whom S. pneumoniae was isolated have mostly been associated with children < or = 12 years of age and adults 60 < or = years olds. These isolates were tested for susceptibility to penicillin G, ampicillin, oxacillin, cefixime, cefdinir, imipenem, panipenem, erythromycin, clindamycin, minocycline, and vancomycin by an agar dilution method using Mueller Hinton agar supplemented with 10% sheep blood. Strains with the MICs > or = 0.125 micrograms/ml for penicillin G were defined as a Pc resistance. Of the 1,127 strains, 471 strains (41.8%) were identified as a Pc resistance. Pcr S. pneumoniae were almost resistant to other beta-lactams, including ampicillin, oxacillin, ceftizoxime, cefixime, cefdinir. Although, the MICs of imipenem and panipenem ragned from 0.004-2.0 micrograms/ml with 2 peaks distributions, these antibiotics inhibited the growth of most of Pcr S. pneumoniae at the lowest concentrations of < or = 0.5 microgram/ml. Only vancomycin resistant strain was not detected in these isolates. Most of the Pcr strains were simultaneously resistant to macrolides and minocycline. Further more, isolation frequencies of Pcr S. pneumoniae in west Japan, were relatively high compared with those of east Japan.