Fifty-one patients admitted to hospital with severe exacerbations of
chronic bronchitis entered a double-blind trial of treatment with
cefaclor (500 mg
tds) compared with
amoxycillin (500 mg
tds) for 7 days. Twenty-six patients received
cefaclor and 25
amoxycillin. Sputum and throat swabs were collected on admission, after 7 days of
therapy and at outpatient follow-up, 3 weeks
after treatment had finished. Clinical status and spirometry were assessed on admission and at the third, seventh and 28th day. There was no significant difference between the two regimes for clinical outcome, spirometry or numbers of infecting pathogens. Opportunistic colonization with resistant Gram-negative organisms and Candida species was highly prevalent on admission (56%) in both groups, perhaps because of previous
antibiotic administration and general
debility of the majority of patients. The high prevalence of opportunistic colonizing organisms persisted at follow-up (48%) with a significant excess of new organisms (Enterobacter cloacae, Klebsiella species and Candida species) present in sputum in the
amoxycillin-treated patients.
Cefaclor may be less damaging to normal flora than
amoxycillin with a consequently reduced risk of colonization and
superinfection of the respiratory tract with resistant Gram-negative organisms and yeasts.