Antimicrobial surveillance of Haemophilus influenzae in the United States during 2000-2001 leads to detection of clonal dissemination of a beta-lactamase-negative and ampicillin-resistant strain.
A 2000-2001 U.S. Haemophilus influenzae surveillance study (n = 1,434) detected nine (0.6%) beta-lactamase-negative and ampicillin-resistant (BLNAR) isolates collected from two different hospitals. The MICs of ampicillin for all nine isolates were 4 microg/ml, with results being reproducible; and all nine isolates were susceptible to amoxicillin-clavulanate, cefuroxime, cefprozil, macrolides, and fluoroquinolones. Pulsed-field gel electrophoresis of genomic DNA following SmaI digestion demonstrated identical patterns for each of the nine isolates, suggesting intra- and interhospital dissemination of a BLNAR clone.
Karlowsky
James A
JA
Focus Technologies, Inc., Herndon, Virginia 20171. 1217 KP Hilversum, The Netherlands. jkarlowsky@focusanswers.com
Critchley
Ian A
IA
Blosser-Middleton
Renée S
RS
Karginova
Elena A
EA
Jones
Mark E
ME
Thornsberry
Clyde
C
Sahm
Daniel F
DF
D000668:Ampicillin Resistance; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000032:analysis*
D001618:beta-Lactamases