Antimicrobial resistance among respiratory pathogens collected in Thailand during 1999-2000

Prevalence and clinical significance of community-acquired penicillin-resistant pneumococcal pneumonia in Thailand

OBJECTIVE

The study aimed to evaluate the prevalence, clinical significance and outcome of community-acquired penicillin-resistant Streptococcus pneumoniae (PRSP) pneumonia in Thailand.

METHODOLOGY

We conducted a prospective study in culture-proven pneumococcal pneumonia. Pneumococci were defined as susceptible, intermediate resistance and high resistance according to the definitions of the United States National Committee for Clinical Laboratory Standards (NCCLS).

RESULTS

Forty-six consecutive patients were enrolled. Of the S. pneumoniae isolates collected, 41.3% were resistant to penicillin (37% intermediate resistance and 4.3% high resistance). Resistance to other antibiotics was 13% to ceftriaxone (8.7% intermediate resistance and 4.3% high resistance), 34.8% to erythromycin, 39.1% to tetracycline, 26.1% to chloramphenicol, and 43.5% to trimethoprim -sulfamethoxazole. Prior antibiotic use within 3 months was significantly associated with resistance to penicillin. The overall mortality of pneumococcal pneumonia was 26.1%. Multilobar involvement and requirement for mechanical ventilation proved to be associated with mortality. However, resistance to penicillin or ceftriaxone was not associated with death.

CONCLUSIONS

According to the US NCCLS guidelines, we found a high prevalence of drug-resistant S. pneumoniae in Thai patients with community-acquired pneumonia. Prior antibiotic use was significantly associated with penicillin resistance. However, the outcome was not related to in vitro penicillin susceptibility of S. pneumoniae isolated from the patients.