Clinical characteristics of pneumonia caused by penicillin resistant and sensitive Streptococcus pneumoniae in Japan.

BACKGROUND

S. pneumoniae is the leading cause of morbidity and mortality worldwide. P-lactam antibiotics were very effective against S. pneumoniae, however resistance to this class of antibiotic has become an increasing problem.

OBJECTIVES

To assess the clinical differences between penicillin-sensitive and penicillin-resistant pneumococcal pneumonia.

METHODS

The medical records of 306 patients with pneumococcal pneumonia who visited Nagasaki University Hospital or affiliated institutions between January 1997 and December 2001 were retrospectively reviewed. The Pneumonia Severity Index (PSI), sensitivity of S. pneumoniae, antibiotic choices and information on clinical outcome were evaluated.

RESULTS

Penicillin sensitive and resistant organisms were responsible for 177 (57.7%) and 129 (42.0%) cases of pneumonia, respectively. The median age of patients was 65.5 years, and 72.3% (222) were males. There were no significant differences in the resistance rate between elderly (>65 years) and young patients. The median PSI score was 76. No significant association was observed between the severity of illness and sensitivities of S. pneumoniae. Previous use of beta-lactams in the last 3 months and chronic obstructive pulmonary disease were associated with penicillin resistance. The failure rate of first line antibiotics was significantly higher in the resistant group (22.5%) than in the sensitive group (9.0%). Four of 306 patients died (mortality, 1.3%).

CONCLUSION

There were no significant differences clinically between the penicillin-sensitive and penicillin-resistant groups. The failure rate of first line antibiotics was higher in the resistant than in the sensitive group. Thus, the selection of antimicrobial agents should be carefully considered in the context of the patient's risk factors.