PNEUMOCOCCAL RESISTANCE IN THE UK

The first case reports of infection with peniciliin-resistant pneumoco cci (PRP, MIC > 0.1 mg/L) and multidrug-resistant pneumococci were mad e in Australia in 1967 and South Africa in 1977, respectively. Since t his time these organisms have spread to become a worldwide problem. In Europe PRP prevalence rates of up to 40% have been reported from Spai n and 58% from Hungary, although there has been considerable national, regional and local variation in these figures. Until recently the UK was considered to have low prevalence of PRP. As recently as 1990, 100 % of 7255 strains of pneumococci from 61 centres across the UK were fo und to be penicillin sensitive. However, there have now been several r eports of significant and rising levels of resistance nationwide. Eryt hromycin resistance has also risen from 2.8% to 8.6% between 1990 and 1995 in England and Wales. At the Northern ireland Public Health Labor atory (NIPHL) 3171 strains of pneumococci were examined using the oxac illin screening test between 1988 and 1995, during which time the annu al rate of penicillin resistance was found to increase from <1% to 10. 6%. The proportion of PRP with high-level resistance (MIG > 1 mg/L) in creased from 0% to 36% and levels of PRP cross-resistance to cephalosp orins and ciprofloxacin were 89% and 78%, respectively, which are amon gst the highest in the UK. Similar rates of penicillin resistance have now been reported from several geographically disparate regions in th e UK including Liverpool, Manchester and London. The number of laborat ories in England and Wales reporting the isolation of PRPs to the Cent ral Public Health Laboratory increased from 23 (3%) in 1987 to 72 (21% ) in 1991 and a recent study from this reference laboratory showed tha t the prevalence of pneumococcal resistance to penicillin had increase d 2.5-fold between 1990 and 1995. Clearly both PRP and multidrug-resis tant pneumococci are increasing in prevalence in the UK, and this incr ease is likely to continue. A recent model of the evolution of nationa l PRP prevalence rates describes a slow emergence phase, followed by a n exponential growth phase of around 10 years reaching a stationary ph ase when the proportion of PRP reaches 50%. It is possible that the UK is currently at the beginning of the exponential growth phase of PRP. This has implications for the future treatment of pneumococcal infect ions in this country and emphasizes the need for new anti-pneumococcal agents. The new quinolone grepafloxacin, which has an MIG(90) of 0.25 mg/L for pneumococci, may represent a future alternative oral treatme nt for multidrug-resistant strains. The activity of this antibiotic ag ainst 70 PRPs is compared with that of two other quinolones and macrol ides.