Vol.57 No.5 September 2009

Antimicrobial susceptibility of Haemophilus influenzae isolated from children with respiratory tract infection

Hiroshi Sakata

Department of Pediatrics, Asahikawa Kosei Hospital, 1-24 Asahikawa, Hokkaido, Japan

Abstract

We studied the minimum inhibitory concentration(MIC) of ampicillin(ABPC), piperacillin(PIPC), cefotaxime(CTX), ceftriaxone(CTRX), meropenem(MEPM), and amoxicillin/clavulanic acid(AMPC/CVA) using the E-test against 179 strains of Haemophilus influenzae isolated between September 2007 and March 2008 from upper nasopharyngeal swabs in children age from 1 month to 15 years old with respiratory tract infection. Of 179 isolates, β-lactamase-negative ABPC-susceptible(BLNAS) strains accounted for 55 (30.7%), β-lactamase-negative ABPC-intermediate-resistant(BLNAI) strains for 41 (22.9%), β-lactamase-negative ABPC-resistant(BLNAR) strains for 73 (40.8%), β-lactamase-positive ABPC-resistant(BLPAR) strains for 2 (1.1%), and β-lactamase-positive AMPC/CVA-resistant(BLPACR) strains for 8 (4.5%). BLNAR incidence was significantly greater than that 5 years earlier (p<0.001). The most frequent MIC in BLNAR increased from 8 μg/mL to 16 μg/mL. MIC₉₀ was 0.38 μg/mL in CTRX, 0.5 μg/mL in PIPC, 1.5 μg/mL in MEPM, and 2 μg/mL in CTX.

Key word

Haemophilus influenzae, drug susceptibility, β-lactamase negative ampicillin resistant, respiratory tract infection, child

Received

March 18, 2009

Accepted

August 11, 2009

Jpn. J. Chemother. 57 (5): 434-437, 2009