Characterization of invasive Neisseria meningitidis strains isolated at the Children's Hospital of Tunis, Tunisia.

Neisseria meningitidis, a leading cause of bacterial meningitis and other serious infections, is responsible for approximately one-third of cases of bacterial meningitis in the Children's Hospital of Tunis. The serogroup distribution, antibiotic susceptibility and antigenic and molecular characteristics of N. meningitidis isolates were determined in patients aged 3 days-13 years between February 1998 and June 2013. In all 107 invasive strains of N. meningitidis were isolated. Reduced susceptibility to penicillin G was seen in 55.7% of isolates, with a low level of resistance in all cases; 28.4% showed a low level of resistance to amoxicillin. Serogroup B isolates were the most frequent (80.4%), followed by serogroups C (12.2%) and A (5.6%). Isolates of serogroup A had the same antigenic formula (A:4:P1.9), the same variable regions VR1, VR2 and VR3, and belonged to the same clonal complex (CC5). Isolates of serogroups B and C were more heterogeneous with several antigenic formulae. The most frequent clonal complex in these isolates was CC35. Serogroup B accounted for a large percentage of our isolates with marked diversity.

[Neisseria meningitidis invasive infections in children in Tunis: about 79 cases]. / Les infections invasives a Neisseria meningitidis chez l'enfant a Tunis : a propos de 79 cas.

We conducted a retrospective study of meningococcal invasive diseases (MID) contracted in children in Tunis between January 1997 and January 2006. The purpose of this study is to specify the clinical, epidemiological, therapeutic and evolutionary features of these infections and to determine antimicrobial susceptibility and the antigenic formula of N. meningitidis isolates. During the study period, we have collected 79 cases of MID arising in children aged 3 days to 11 years. The majority of children's were less than of 4 years (57.3%). We note a frequency of the MID in winter and in spring. The most frequent clinical shape was meningitis (53%). Twenty one patients (26.6%) had a fulminant meningococcal disease. In our series, the rate of lethality was equal to 17.7%. Among the 46 meningococcal isolates, the most frequent serogroup was the B (73%) followed by C and A. A high heterogeneousness of the antigenic formulae was observed The most frequent phenotype was NT: NST for the group B isolates and 4:P1.13 for the group C ones. N meningitidis with reduced susceptibility to penicillin and to amoxicillin account for 54% and 10% of all isolates respectively. The cefotaxim and the rifampin were uniformly active.