Antibiotic resistance among recent clinical isolates of Haemophilus influenzae in Japanese children.
From January 1997 to July 1999, a total of 867 isolates of Haemophilus influenzae were recovered in the microbiology laboratory of Chiba Children's Hospital. The overall prevalence of beta-lactamase production was 12.8%. Ampicillin-MICs for all of the 111 beta-lactamase-producing isolates was > or =4 microg/ml. A total of 26 beta-lactamase-negative isolates (3.4% of all beta-lactamase-negative isolates and 3.0% of all isolates) were found to be resistant to ampicillin. The prevalence of beta-lactamase negative ampicillin-resistant strains (BLNAR) increased remarkably to 8.9% during the last 7-month period. It is noteworthy that the MICs not only of penicillins but also of cephems for BLNAR were significantly higher than those for ampicillin-susceptible isolates. Eight beta-lactamase-producing isolates of H. influenzae (7.2% of all beta-lactamase-producing isolates) were resistant to amoxicillin-clavulanate (AMPC/CVA). Consequently, the overall resistance to ampicillin was 15.8%, and that to AMPC/CVA was 3.0%. The results of this study corroborate the findings of previous investigators in the US (Doern et al., 1997) regarding the emergence of BLNAR and beta-lactamase-producing AMPC/CVA-resistant strains (BLPACR) of H. influenzae. Continued monitoring of susceptibility trends will be required to guide appropriate chemotherapy.
Ohkusu
K
K
Institution:Division of Clinical Laboratory, Chiba Children's Hospital, 579-1 Heta cho, Midori-ku, Chiba-City, Japan. okiyo@apricot.ocn.ne.jp
Nakamura
A
A
Sawada
K
K
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan; D007769:Lactams; D008297:Male; D008826:Microbial Sensitivity Tests; D018440:beta-Lactam Resistance
D000900:Anti-Bacterial Agents; D007769:Lactams