[Studies of treatment for Haemophilus influenzae type b meningitis in children].

We summarize 41 cases of bacterial meningitis in the last 11 years caused by Haemophilus influenzae. All isolates were serotype b strain (Hib). Initial chemotherapy was started with ceftriaxone (CTRX) in 22 cases, ampicillin plus cefotaxime (CTX) in 9, CTRX plus panipenem/betamipron in 5, and CTX in 2. Some 31 cases were treated mainly with CTRX. Although therapeutic antibiotics showed good susceptibility for isolates, 8 complicated cases (19.5%) occurred. Sequalae were observed in 7 (17.1%) but none were fatal. Five strains with elevated MIC of CTX (0.12 to 1 microg/mL) recovered after 2001, and 3 of 5 strains also showed elevated MIC of CTRX (0.12 to 0.5 microg/mL), but all were cured completely with CTRX. At present, no treatment failures due to antibiotic resistance have been observed, and CTRX remains suitable as initial therapy for Hib meningitis. A decline in susceptibility for third-generation cephalosporin against beta-lactamase-nonproducing ampicillin-resistant H. influenzae is emerging, however, so it will be necessary to consider combination therapy with CTRX given the foreseeable trend in MICs.

[Clinical effects of piperacillin and tazobactam/piperacillin on Haemophilus influenzae lower respiratory tract infection in pediatric patients].

OBJECTIVE: The prevalence of beta-lactamase-nonproducing ampicillin-resistant (BLNAR) Haemophilus influenzae (H. influenzae) has been increasing in recent years. Piperacillin (PIPC) is one of a few beta-lactams possessing good activity against BLNAR H. influenzae. We studied clinical efficacy of piperacillin and its beta-lactamase inhibitor, tazobactam/piperacillin (TAZ/PIPC) in children with lower respiratory tract infection caused by H. influenzae including resistance strains. METHODS: Subjects were 20 children with lower respiratory tract infection caused by H. influenzae treated with PIPC 100mg/kg/day (7 cases) or TAZ/PIPC 125mg/kg/day (13 cases). We selected cases from which resistant H. influenzae strains might be detected. Patients received prior antimicrobial therapy within two weeks before admission, or with underlying diseases. We examined patient profiles, clinical efficacy, susceptibilities for 6 beta-lactam antibiotics [PIPC, TAZ/PIPC, ampicillin (ABPC), cefotaxime (CTX), ceftriaxone (CTRX), and meropenem (MEPM)] and analyzed 6 genotype patterns of beta-lactam resistant genes by PCR. RESULTS: Efficacy was 7/7 in patients in PIPC group and 12/13 in patients in TAZ/PIPC group. Diminished efficacy was seen in only one case complicated with severe RSV infection. The susceptibility of all strains but one beta-lactamase producing, ABPC resistant (BLP) strain to PIPC and of all to TAZ/ PIPC was below 0.25 microg/mL. The genotype of the 15 strains isolated from the sputum on administration was as follows; beta-lactamase nonproducing, ABPC-susceptible (gBLNAS) strains were 4, gBLP strain was 1, beta-lactamase nonproducing, and ABPC-resistant (gLow-BLNAR) strains were 2, beta-lactamase nonproducing, ABPC resistant (gBLNAR) strains were 8. CONCLUSION: PIPC and TAZ/PIPC were useful against lower respiratory tract infection caused by H. influenzae including BLNAR in children.

[Successful treatment of beta-lactamase-negative ampicillin-resistant Haemophilus influenzae type b meningitis with high-dose ceftriaxone administration].

Haemophilus influenzae type b (Hib) is the most frequent pathogen of bacterial meningitis in Japanese children. The prevalence of beta-lactamase-negative ampicillin-resistant (BLNAR) Hib strain has been increasing in recent years. Furthermore, antibiotic activities of cefotaxime (CTX) and ceftriaxone (CTRX) have decreased against some of those BLNAR strains. We report a case of one-year-old boy who suffered from meningitis caused by BLNAR Hib. The MICs of CTX and CTRX for the strain isolated from cerebrospinal fluid was 1.0 and 0.5 microg/ml, respectively. The patient was administered high-dose CTRX (150 mg/kg/day) and recovered completely without any sequela. The high-dose CTRX administration may be a considerable choice of the treatment of BLNAR meningitis.

[Antimicrobial susceptibility testing of clinical isolates of Haemophilus influenzae derived from Japanese children].

We examined the antimicrobial susceptibility testing of 1,024 Haemophilus influenzae isolates recovered from Japanese children. Percent distribution of beta-lactamase-negative ampicillin (ABPC)--resistant strain (BLNAR; ABPC-MIC > or = 4 microg/ml) was 15.0%. Prevalence of BLNAR increased remarkably from 12.7 to 22.1% in recent 4 years. Furthermore, the frequency of highly resistant strains (ABPC-MIC > or = 8 microg/ml) increased from 28.6 to 56.9% among BLNAR. Decreased susceptibility for cephems was observed in non-BLNAR strains including serotype b strain isolated from the cerebrospinal fluid.