Document Detail


Differentiation of beta-lactamase-negative ampicillin-resistant Haemophilus influenzae from other H. influenzae strains by a disc method.
MedLine Citation:
PMID:  11957120     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We established breakpoints for differentiating ampicillin (ABPC)-susceptible strains from resistant strains among Haemophilus influenzae isolates according to susceptibility to various beta-lactam antibiotics, using a disc method. Susceptibility testing of isolates for 13 beta-lactam agents was followed by analysis of the resistance genes, using a polymerase chain reaction (PCR) to identify the TEM-1 beta-lactamase gene ( bla) and the ftsI gene encoding penicillin-binding protein (PBP) 3, which affects beta-lactam minimum inhibitory concentrations (MICs). A total of 228 H. influenzae isolates were classified into 114 beta-lactamase-negative, ABPC-susceptible (BLNAS) strains; 29 beta-lactamase-negative, ABPC-resistant (BLNAR) strains; 53 low-BLNAR strains with a low degree of ABPC resistance; 27 TEM-1-producing strains (BLPAR); and 5 strains with ftsI gene mutations in addition to TEM-1 production (BLPACR) according to the PCR results. To identify resistant strains by disc-method susceptibility testing, the zone of inhibition was measured for ABPC (10 microg/disc), cefaclor (30 microg/disc), cefpodoxime (10 microg/disc), and cefdinir (5 microg/disc) discs. Strains were identified as BLNAS without resistant genes when the diameter was > or =27 mm for the ABPC disc and > or =21 mm for the cefaclor disc. Other strains were identified as BLNAR when the diameter was < or =22 mm for the cefpodoxime disc and < or =17 mm for the cefdinir disc. Remaining strains were identified as low-BLNAR. These criteria differentiated resistance types with high accuracy. A discrepancy was noted between genetic results and disc-testing breakpoints for differentiating resistant from susceptible H. influenzae. A disc-testing breakpoint for cefditoren (5 microg/disc) was proposed, with the susceptibility statistically defined as a diameter of > or =24 mm, which corresponds to the breakpoint (1 microg/ml) of the microdilution method recommended by the Japanese Society of Chemotherapy.
Authors:
Kimiko Ubukata; Naoko Chiba; Keiko Hasegawa; Yumi Shibasaki; Keisuke Sunakawa; Masato Nonoyama; Satoshi Iwata; Masatoshi Konno
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy     Volume:  8     ISSN:  1341-321X     ISO Abbreviation:  J. Infect. Chemother.     Publication Date:  2002 Mar 
Date Detail:
Created Date:  2002-04-16     Completed Date:  2002-05-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9608375     Medline TA:  J Infect Chemother     Country:  Japan    
Other Details:
Languages:  eng     Pagination:  50-8     Citation Subset:  IM    
Affiliation:
Center for Epideniology and Clinical Microbiology, Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd., 760 Morookacho, Kohoku-ku, Yokohama 222-8567, Japan. kimiko_ubukata@meiji.co.jp
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MeSH Terms
Descriptor/Qualifier:
Ampicillin Resistance
Anti-Bacterial Agents / pharmacology
Haemophilus influenzae / drug effects*,  enzymology
Humans
Microbial Sensitivity Tests / methods*
beta-Lactamases / metabolism*
beta-Lactams
Chemical
Reg. No./Substance:
0/Anti-Bacterial Agents; 0/beta-Lactams; EC 3.5.2.6/beta-Lactamases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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