SEROTYPES AND ANTIBIOTIC SUSCEPTIBILITY PATTERN OF STREPTOCOCCUS PNEUMONIAE ISOLATES AT AHMADU BELLO UNIVERSITY TEACHING HOSPITAL, ZARIA

Abstract

Pneumococcal infections remain major causes of morbidity and mortality in persons of all ages
worldwide despite antibiotic usage.
The aim of the study was to obtain a knowledge of the prevalence and serotypes of Streptococcus
pneumoniae isolates in Ahmadu Bello University Teaching Hospital (ABUTH), Zaria. While
also determining the antibiotic susceptibility pattern of Streptococcus pneumoniae by the disc
diffusion method. To identify Streptococcus pneumoniae serotypes associated with invasive
infections and the minimum inhibitory concentration of Streptococcus pneumoniae to
penicillin.
A total number of 420 clinical specimens were cultured only 23 strains of Streptococcus
pneumoniae were isolated and confirmed for Streptococcus pneumoniae from different
specimens over a period of 18months.Antibiotic susceptibility testing was carried out using the
following antibiotics : oxacillin(1ug),erythromycin(15ug),cotrimoxazole (25ug),
chloramphenicol(30ug),ciprofloxacin(5ug),benzylpenicillin(10ug),cefuroxime (30ug),ceftriaxone
(30ug). Minimum Inhibitory Concentration using E-test was carried out for benzylpenicillin on
the isolates which were resistant to oxacillin.
The prevalence of Streptococcus pneumoniae was found to be 5.4%.Out of the Streptococcus
pneumoniae strains, 52.2% were obtained from blood and 26.1% from sputum. No isolate was
obtained from cerebrospinal fluid(CSF), pus, aspirates and wound swabs. Majority of the
isolates(95.7%) were sensitive to ciprofloxacin and 90.9% to chloramphenicol, 52.2% to
ceftriaxone while only 34.8% were sensitive to cefuroxime and 30.4% to benzyl penicillin.
3
Minimum inhibitory concentration (MIC) done using the E-Test method for 18 resistance
strains to penicillin, showed a level of high resistance to penicillin ranging from 0.75 mg/ml
6mg/ml.
The major serotypes found in this study were 6,19 and 20 and all were from blood. Serotype 6
was the commonest .All the Isolates from sputum were found untypable.
It is evident that penicillins are no longer effective in the treatment of invasive pneumococcal
infection. Pneumococcal vaccines should be implemented in the National Programme on
Immunization in developing countries in order to reduce the mortality and morbidity caused by
Streptococcus pneumoniae infections. Strategies to promote appropriate prescribing and
dispensing of effective antibiotics should be immediately implemented for the benefit of local
and global health. Surveillance for laboratory confirmed pneumococcal disease is useful and
should be implemented