title: Rapidly increasing prevalence of beta-lactamase-nonproducing, ampicillin-resistant Haemophilus influenzae type b in patients with meningitis.
abstract: A total of 395 Haemophilus influenzae strains from 226 Japanese institutions participating in the Nationwide Surveillance Study Group for Bacterial Meningitis were received from 1999 to 2002. All strains were analyzed by PCR to identify the resistance genes, and their susceptibilities to beta-lactam agents were determined. Of these strains, 29.1% were beta-lactamase nonproducing and ampicillin (AMP) susceptible (BLNAS) and lacked all resistance genes; 15.4% were beta-lactamase producing and AMP resistant and had the bla(TEM-1) gene; 30.6% were beta-lactamase nonproducing and AMP resistant (low-BLNAR) and had a Lys-526 or His-517 amino acid substitution in ftsI encoding PBP 3; 13.9% were beta-lactamase nonproducing and AMP resistant (BLNAR) and had an additional substitution of Thr-385 in ftsI; 9.1% were amoxicillin-clavulanic acid resistant (BLPACR I) and had the bla(TEM-1) gene and a Lys-526 or His-517 amino acid substitution in ftsI; and 1.8% showed resistance similar to that of the BLPACR I group (BLPACR II) but had bla(TEM-1) gene and ftsI substitutions, as was the case for the BLNAR strains. All but three strains were serotype b. The prevalence of BLNAR strains has increased rapidly: 0% in 1999, 5.8% in 2000, 14.1% in 2001, and 21.3% in 2002. The MICs at which 90% of BLNAR isolates were inhibited were as follows: AMP, 16 micro g/ml; cefotaxime, 1 micro g/ml; ceftriaxone, 0.25 micro g/ml; and meropenem, 0.5 micro g/ml. All of these values were higher than those for the BLNAS counterpart strains. The relatively wide distributions of the beta-lactam MICs for BLNAR strains presumably reflect variations in ftsI gene mutations. Pulsed-field gel electrophoresis suggested the rapid spread of specific H. influenzae type b strains throughout Japan. Expedited vaccination, rapid identification, and judicious antibiotic use could slow their spread.
authors.affiliation: Kitasato Institute for Life Sciences & Graduate School of Infection Control Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Japan. keiko@lisci.kitasato-u.ac.jp
authors.forename: Keiko
authors.initials: K
authors.lastname: Hasegawa
authors.forename: Naoko
authors.initials: N
authors.lastname: Chiba
authors.forename: Reiko
authors.initials: R
authors.lastname: Kobayashi
authors.forename: Somay Y
authors.initials: SY
authors.lastname: Murayama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iwata
authors.forename: Keisuke
authors.initials: K
authors.lastname: Sunakawa
authors.forename: Kimiko
authors.initials: K
authors.lastname: Ubukata
mesh_terms: D000367:Age Factors; D000668:Ampicillin Resistance; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D019741:Haemophilus influenzae type b / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006602:Hexosyltransferases / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D008583:Meningitis, Haemophilus / Q000453:epidemiology / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D002267:Muramoylpentapeptide Carboxypeptidase / Q000235:genetics; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014481:United States; D001618:beta-Lactamases / Q000378:metabolism*; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D046915:Penicillin-Binding Proteins; D047090:beta-Lactams; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D001618:beta-Lactamases