Antimicrobial resistance of pneumococci in children with acute lower respiratory tract infection in Pakistan.

87 strains of Streptococcus pneumoniae isolated during three winter seasons (1986-89) from the blood of children with acute lower respiratory tract infection (ALRI) in Pakistan were serotyped and tested for susceptibility to a range of antimicrobial agents. 97% of isolates were resistant to at least one antimicrobial drug. 62% had decreased susceptibility to co-trimoxazole (trimethoprim/sulphamethoxazole) (31% were fully resistant) and 39% were resistant to chloramphenicol. All isolates were susceptible to erythromycin, cefaclor, cephalothin, ceftriaxone, cefuroxime, rifampicin, vancomycin, and clindamycin. 29% of isolates were neither vaccine types nor vaccine-related types. Serotype distribution and antimicrobial susceptibility varied significantly during the three winter seasons. No single serotype was found in all three winters. The findings highlight the need for surveillance of antimicrobial resistance and serotype distribution of S pneumoniae in developing countries as a guide both to the choice of agent for treatment of pneumococcal infections, especially ALRI, and to the formulation of new pneumococcal conjugate vaccines for use in young children.