UMMS Affiliation

Department of Clinical Microbiology

Date

2-1-1988

Document Type

Article

Subjects

Ampicillin Resistance; Anti-Bacterial Agents; Cefaclor; Cefamandole; Cephalexin; Cephalothin; Chloramphenicol Resistance; Drug Combinations; Drug Resistance, Microbial; Erythromycin; Haemophilus influenzae; Humans; Rifampin; Sulfamethoxazole; Tetracycline Resistance; Trimethoprim; Trimethoprim-Sulfamethoxazole Combination; United States; beta-Lactamases

Disciplines

Microbiology

Abstract

A total of 2,811 clinical isolates of Haemophilus influenzae were obtained during 1986 from 30 medical centers and one nationwide private independent laboratory in the United States. Among these, 757 (26.9%) were type b strains. The overall rate of beta-lactamase-mediated ampicillin resistance was 20.0%. Type b strains were approximately twice as likely as non-type b strains to produce beta-lactamase (31.7 versus 15.6%). The MICs of 12 antimicrobial agents were determined for all isolates. Ampicillin resistance among strains that lacked beta-lactamase activity was extremely uncommon (0.1%). Percentages of study isolates susceptible to cefamandole, cefaclor, cephalothin, and cephalexin were 98.7, 94.5, 87.3, and 43.3%, respectively. For 14 strains (0.5% of the total), chloramphenicol MICs were greater than or equal to 8.0 micrograms, and thus the strains were considered resistant. All of these resistant strains produced chloramphenicol acetyltransferase. In addition, all 14 strains were resistant to tetracycline; 11 produced beta-lactamase. The percentage of isolates susceptible to tetracycline was 97.7%. In contrast, erythromycin and sulfisoxazole were relatively inactive. The combination of erythromycin-sulfisoxazole (1/64) was more active than erythromycin alone but essentially equivalent in activity to sulfisoxazole alone. Finally, small numbers of clinical isolates of H. influenzae were resistant to trimethoprim-sulfamethoxazole and rifampin.

Rights and Permissions

Citation: Antimicrob Agents Chemother. 1988 Feb;32(2):180-5.

Related Resources

Link to article in PubMed

Journal Title

Antimicrobial agents and chemotherapy

PubMed ID

3259121

Included in

Microbiology Commons

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.