Macrolide-resistant Streptococcus pneumoniae and use of antimicrobial agents

The prevalence of isolates of Streptococcus pneumoniae (pneumococcus) that are resistant to antimicrobial agents is increasing globally. We studied th e connection between antimicrobial resistance of pneumococci and regional u se of antimicrobial agents in Finland. In 1997, a total of 6106 pneumococca l isolates were identified in clinical microbiology laboratories in Finland . Most of the pneumococci were isolated from respiratory tract samples, 8% were from blood culture samples, and 0.5% were from cerebrospinal fluid sam ples. The regional levels of resistance for pneumococci in 1997 were compar ed with the regional rates of use of antimicrobial agents from 1995 through 1996. We found that resistance to macrolides correlated highly significant ly with macrolide use (P=.006). A significant correlation was also found be tween resistance to trimethoprim-sulfamethoxazole and trimethoprim-sulfamet hoxazole use (P=.043). We did not find a correlation between penicillin res istance and the use of any antimicrobial agent. The positive correlation be tween macrolide-resistant pneumococci and the use of macrolides is worrying , because macrolides are used worldwide in the treatment of patients with r espiratory tract infections, which are often caused by pneumococci.