Characterization of invasive Pneumococcal isolates recovered from patients in two Selected Hospitals, Ethiopia

Abstract

Background: Pneumococcus is a major public health challenge with high frequency of infection and serotype diversity.

Objective: This study aims at serotyping, sequence typing and antimicrobial susceptibility profiling of pneumococcal isolates circulating in selected health facilities of Ethiopia.

Methods: A total of 228 cerebrospinal fluid samples were collected from hospitalized patients at University of Gondar Hospital and Black Lion Specialized Hospital during June –December, 2012.  Samples were processed using both conventional and modern microbiological techniques. Serotype was determined by Quelung reaction. Antimicrobial susceptibility test was performed using E-test. Real Time –polymerase chain reaction and Multilocus sequence typing was also done for confirmation test and genotyping of isolates, respectively.

Results: Sixty eight pneumococcal isolates were recovered (26.3%) from the total 228 processed samples. Of these, 15 serotypes were identified, with serotype 1 (21%) being the leading followed by 19F and 20 (each 10%), and serotype 14 (8%). More than one serotype was identified in seven of the samples. Seventeen sequence types (mainly, ST1203, ST1475, ST217, and ST6451) were identified, of which seven of them were novel. RT-PCR analysis of 140 culture negative cerebrospinal fluid samples detected 12 Neisseria meningitidis, nine Streptococcus pneumoniae and 2 mixed strains.

Conclusion:  Serotype 1 was predominantly found in suspected meningitis patients admitted in the study hospitals. Novel variants of pneumococcal sequence types that are new for the Streptococcus pneumoniae MLST database were also identified.