Neisseria meningitidis: evolution of penicillin resistance and phenotype in a children's hospital in Barcelona, Spain

Neisseria meningitidis is the most prevalent micro-organism involved in pae diatric bacterial meningitis in the Barcelona area in children over 3 mo of age and it is an important cause of morbidity and mortality in Spain. A to tal of 498 strains of N. meningitidis, obtained between the years 1986 and 1997 from children with sepsis and/or meningitis, were characterized accord ing to their serogroup and penicillin resistance; their distribution in ser otypes and subtypes was studied from 1990. A decreasing tendency in the num ber of annual isolates was observed in this period. Most isolates belonged to serogroups B (403 strains) and C (77 strains). Serogroup C accounted for 1.8% of the strains in 1986 and 57.1% in 1997. The most prevalent phenotyp e between 1990 and 1996 was B:4:P1.15, but C:2b:P1.2,5 was the most prevale nt in 1997. Overall penicillin-resistance rates ranged from 9.1% in 1986 (w hen a non-susceptible strain was isolated for the first time in the Hospita l Sant Joan de Deu, Barcelona, Spain) to 71.4% in 1997, and it was more com mon among strains belonging to serogroup C (52% of resistant strains) than to serogroup B (22.1% of resistant strains). The penicillin-resistance leve l was low, MIC always less than or equal to 0.5 mu g/ml. The present increa se in N. meningitidis group C isolates, mainly C:2b:P1.2,5, and the availab ility of preventive measures for this highly pathological and resistant phe notype, argues strongly for the establishment of an epidemiological monitor ing system. Detection of penicillin resistance should be standardized world wide in order to unify data from all laboratories. Conclusion: A shift between serogroups B and C is observed in Barcelona fro m 1986 to 1997 as well as a rapid distribution of decreased penicillin susc eptibility.