Effectiveness of immunoprophylaxis in suppressing carriage of Neisseria meningitidis in the military environment.

Neisseria meningitidis, etiological factor of invasive meningococcal disease, is a human commensal that colonizes the nasopharynx. Colonization is usually asymptomatic, but it is a prerequisite for disease. Asymptomatic carriers are the major source of infection. In the present study, a survey of N. meningitidis carriage was conducted between January and March 2013 in a military unit in Poland. Single-time throat culture samples were collected from professional 559 soldiers (302 unvaccinated vs. 257 vaccinated individuals with the quadrivalent conjugate vaccine ACYW-135). Bacterial identification was performed with classic microbiological methods (culture, incubation, identification). Non-culture method (PCR) was used for confirmation of detected strains of N. meningitidis and determination of serogroups. We found 29 carriers in the group of unvaccinated soldiers (9.6 % of examined individuals) whereas among vaccinated soldiers only 3 persons were carriers of N. meningitidis (1.2 %). The most frequently identified serogroups among the carriers serving in the same military facility were serogroup B (28 %), followed by Y (25 %), and C (22 %). In conclusion, the initiation of mass vaccination with the quadrivalent conjugate vaccine ACYW-135 in the military environment seems an effective method of suppressing N. meningitidis carriage.

Recent trends in epidemiology of invasive pneumococcal disease in Poland.

The objectives of this study were to assess the current incidence of invasive pneumococcal disease (IPD) in Poland (2011-2013), where mass vaccination has not been implemented, and to characterize the Streptococcus pneumoniae isolates responsible for invasive infections by determining their serotype distribution and antimicrobial resistance patterns. For all isolates identification, serotyping and antimicrobial minimal inhibitory concentrations determination were performed based on routine techniques. The highest incidence rates were observed among adults older than 85 years old (4.62/100,000) and children under 1 year of age (4.28/100,000). The general case fatality ratio (CFR) was 25.4%, with the highest CFR in the age group ≥85 years old (59.7%). The most common serotypes were 3, 14, 19A, 4, 9V, 19F, 1, and 23 F (61.3% of all isolates). The 10- and 13-valent pneumococcal conjugated vaccines (PCV) covered 46.0 and 71.8% of all IPD cases, 61.4 and 79.5% of cases in children under two years, and 60.4 and 78.6% of cases involving children under five years of age, respectively. The PCV13 and 23-valent polysaccharide vaccine covered 68.7 and 86.0% of cases in adults >65 years old, respectively. Decreased susceptibility was noted for penicillin (24.8%), cefotaxime (10.0%), meropenem (5.0%), rifampicin (0.8%), chloramphenicol (4.3%), erythromycin (29.7%) and clindamycin (25.6%). Multi-drug resistance characterized 21.6% of the pneumococci tested. Despite deficiencies in the Polish surveillance system and strong underestimation of IPD cases, results of the study showed good theoretical coverage of PCV, which should encourage inclusion of anti-pneumococcal conjugate vaccine into the national immunization program.

Resistance patterns of selected respiratory tract pathogens in Poland.

This study presents the results of a survey of the in-vitro susceptibility to antimicrobial agents of major pathogens responsible for community-acquired respiratory tract infections in Poland during 2002-2004. The collection of 1184 bacterial isolates comprised 398 Streptococcus pneumoniae, 344 Haemophilus influenzae, 302 Streptococcus pyogenes and 140 Moraxella catarrhalis. Among the pneumococcal isolates, 16.8% were penicillin-non-susceptible (PNSP), of which 80.6% were identified as multidrug-resistant. Overall, 9.0% of H. influenzae isolates were beta-lactamase-positive, although this percentage increased noticeably in the third year of the study. Based on PCR results, 12.8% of H. influenzae isolates were identified as low-level beta-lactamase-negative, ampicillin-resistant (BLNAR), and one isolate as low-level beta-lactamase-positive, amoxycillin-clavulanic acid-resistant (BLPACR). Pulsed-field gel electrophoresis (PFGE) classified 45 H. influenzae isolates with altered penicillin-binding proteins into 15 PFGE types, including two predominant types (with four and six sub-types) containing 15 and ten isolates, respectively. Resistance to tetracycline, erythromycin and clindamycin was found in 20.9%, 8.9% and 4.6% of S. pyogenes isolates, respectively. The production of beta-lactamase characterised 91.4% of M. catarrhalis isolates. In summary, the overall occurrence of PNSP in Poland remains stable, although there was a noticeable increase in the proportion of fully-resistant isolates. A rising trend in the prevalence of beta-lactamase producers and low-level BLNAR isolates was observed among Polish isolates of H. influenzae.

Characterisation of Neisseria meningitidis C:2b:P1.2,5 isolates in Poland.

This study aimed to characterise Neisseria meningitidis C:2b:P1.2,5 isolates from Poland, which have now become predominant among serogroup C isolates in this country. Overall, 44 isolates (25 invasive and 19 from contact carriers) were typed by whole-cell ELISA and pulsed-field gel electrophoresis. Additionally, the invasive isolates were analysed by multilocus sequence typing, which revealed that they all belonged to the ST-8 complex/cluster A4. The emergence of this clone in other countries has resulted in mass immunisation campaigns and has been associated with a higher level of decreased susceptibility to penicillin; however the present study detected only one isolate that was penicillin-non-susceptible.