A comparative clinical study of pneumonia by penicillin-resistant and -sensitive Streptococcus pneumoniae in a community hospital.
This study aimed to determine the clinical difference of pneumonia between penicillin-resistant and penicillin-sensitive Streptococcus pneumoniae. Forty-nine cases in 46 patients of pneumococcal pneumonia were studied from December 1992 to May 1997. There were 24 cases (in 22 patients) of penicillin-resistant pneumococci (PRSP) pneumonia which were compared with 25 cases (in 24 patients) with penicillin-sensitive pneumococci (PSSP). Both the mean age and the underlying disease states did not differ between the two groups. However, hospital-acquired pneumonia and previous use of antibiotics were observed in eight (33.3%) and 12 (50.0%) patients in PRSP compared with three (12.0%) and two (8.0%) in PSSP, respectively. The clinical efficacy rate and bacteriological eradication rates were 87.5 and 87.5% in PRSP compared with 87.5 and 87.0% in PSSP, respectively. Minimum inhibitory concentration (MIC) of antibiotics against 30 pneumococcal isolates was examined, and 10 strains ranged from 0.10-0.78 microg/mL and five strains were more than 1.56 microg/mL against penicillin G, while the MIC showed higher resistance to other antibiotics except for the carbapenems. Serotyping of the isolates by antiserum revealed differences in the predominant types PRSP (19F) and PSSP (6A,9V) [corrected]. We must care for not only community-acquired infection but also nosocomial transmission of PRSP pneumonia. Most patients with infections due to PRSP tended to have a milder illness with a good outcome (no patient died). As such it appears that empiric therapy for pneumococcal pneumonia does not require modification from what is recommended at present. However, in patients with infection due to highly resistant strains, and who are not responding to conventional therapy should have their treatment modified according to subsequent susceptibility testing.