back to 2010, vol. 16, b. 3

Journal of IMAB - Annual Proceeding (Scientific Papers)
Publisher: Peytchinski, Gospodin Iliev
ISSN: 1312 773X (Online)
Issue: 2010, vol. 16, book 3
Subject Collection: Medicine
Page: 66 - 69
DOI: 10.5272/jimab.1632010_66
Online date: February 8, 2011

Tomislav Kostyanev*, L. Setchanova, V. Ouzounova-Raykova, Y. Proevska, I. Mitov
Department of Medical Microbiology, Faculty of Medicine, Medical University - Sofia, Bulgaria

A total of 175 H. influenzae strains were collected between 1994 and 2009 from all aged patient groups. The strains were isolated from patients with invasive and community-acquired respiratory tract infections. All strains were identified according to standard microbiological methods. Serotyping was done by a coagglutination test and by molecular PCR capsular genotyping. Beta-lactamase production was determined by the chromogenic cephalosporin test with nitrocephin as substrate.
Most of the isolated H. influenzae strains were from children under 5 years of age (57.7%). Overall, 61 strains belonged to serotype b (34.9%) by the means of PCR capsular typing, 1 strain was type f, and 113 isolates (64.6%) were non-typeable (non-encapsulated) H. influenzae. Among the infants and children with meningitis or other invasive infections, aged 2 month to 5 years, all strains, except one, were serotype b. In respiratory tract infections (pneumonia, otitis media, sinusitis and people with chronic pulmonary diseases - exacerbations of COPD, bronchiectasis, cystic fibrosis) the most common - 96.5% were non-typeable strains in both groups children and adults. Overall, the prevalence of beta-lactamase production was 19.4%. But, it was much higher for invasive strains from CSF isolates - 37.7%, 25% in blood samples, and 37.5% in otitis media causative strains. Beta-lactamase production was less frequent in respiratory tract isolates - in sputum 13.3% and in URT samples - 2.3%. The rate of beta-lactamase production in CSF isolates has not changed for the last 10 years.
PCR capsular genotyping method has to be performed for all non-b-type strains. The implementation of Hib vaccine in our country will be accompanied by a reduction in invasive diseases caused by H. influenzae type b in children, but it is not useful in preventing infections caused by non-typeable H. influenzae strains.

Key words:  H. influenzae, capsular genotyping, non-typeable H. influenzae, beta-lactamase .

Page: 66-69; FULL TEXT PDF (286 KB) Abstract

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