A survey of β-lactamase-producing Haemophilus influenzae an evaluation of 5750 isolates

Previous studies have reported that 15%–34% of Haemophilus influenzae produce β-lactamase. A surveillance program was developed by SmithKline Beecham Clinical Laboratories to determine the current percentage of β-lactamase-producing H. influenzae from five selected geographic locations in the United States. In 1993, results of 5750 isolates from specimens submitted to five reference clinical laboratories were evaluated. Data were collected from 29 states and the District of Columbia. The percentages of β-lactamase-producing H. influenzae was 33% and ranged from 22%–40% for the individual states.