Epidemiology of Penicillin-resistant Pneumococci in a Merseyside Health District over a 14-year Period

Abstract Objectives: To determine the prevalence and epidemiology of penicillin-resistant Streptococcus pneumoniae isolates in the St Helens and Knowsley Health District of Merseyside. Methods: Penicillin-resistant pneumococci were isolated from clinical samples taken from 549 patients between January 1987 and December 2000. Patient profile, bacterial serotype and resistance patterns were analysed. Results: Between January 1987 and December 2000, the prevalence of penicillin-resistant pneumococci increased from 1.4% to a peak of 12.9% in 1997, subsequently falling to 8.9%. High-level penicillin resistance was found in 243 (44.3%) of the isolates. Two hundred and eighty isolates were from children (mean age 2.2 years), of whom only 25% were clinically infected. Two hundred and sixty nine isolates were from adults (average age 68.4 years) of whom 88% were infected. Over 65% of isolates were community acquired with 53% of patients having received antibiotics in the 3 months prior to their first isolate. Twenty six per cent of patients had underlying disease of the respiratory tract. The changing evolution of serotypes over the 14 years of the study was associated with changes in sensitivity patterns. Serotype 9 was the most common serotype (36%). Conclusions: The study demonstrates the evolution of penicillin resistance in the patient population of this District over the past 14 years.