The prevalence of antibiotic resistance in Haemophilus influenzae in Wales. Report from the Standing Specialist Advisory Group for Microbiology in Wales.

From January to April 1986 all 21 Clinical Microbiology Laboratories in Wales took part in a survey to determine the prevalence of antibiotic resistance in Haemophilus influenzae. All isolates were collected and despatched to a central laboratory where identification was confirmed and antibiotic sensitivity tests repeated. One thousand four hundred and forty strains were available for analysis. Resistance was present in 128 (8.9%) to ampicillin, 23 (1.6%) to cefaclor, 28 (1.7%) to chloramphenicol, 282 (19.6%) to erythromycin, 43 (3.0%) to tetracycline, 90 (6.2%) to sulphonamide and 66 (4.6%) to trimethoprim. One hundred and twenty-one strains (8.4%) were beta-lactamase producers. Thirteen (0.9%) were resistant to four or more antibiotics and included one type b strain isolated from cerebrospinal fluid resistant to ampicillin, chloramphenicol, tetracycline, trimethoprim and sulphonamide. The prevalence of resistance to ampicillin and trimethoprim was higher than that recorded previously in two large studies elsewhere in the United Kingdom. Ampicillin resistance was more common in strains from hospital inpatients than those from general practice.