Streptococcus Pneumoniae Serotype Prevalence, Antibiotic Susceptibility And Associated Risk Factors Among Children Attending Gertrudes Children’s Hospital In Nairobi City County-Kenya

ABSTRACT

Pneumococcal disease remains the biggest killer of children living in Kenya. This is true despite inclusion of the 10-valent pneumococcal conjugate vaccine in the Kenya Expanded Program on Immunization. Serotype replacement, emergence of antibiotic resistance, inaccurate laboratory diagnosis due to optochin resistant bacterial types and a range of environmental and host related risk factors have been touted to be the cause of these statistics elsewhere. This study sought to establish prevalence of Streptococcus pneumoniae serotypes, antibiotic susceptibility patterns and associated risk factors among PCV-10 vaccinated and unvaccinated children attending Gertrude’s Childrens Hospital. A total of 206 children were recruited for this study. Nasopharyngeal swabs were the main specimen used. Culturing and isolation of the bacteria was done on blood agar with gentamicin and plain blood agar plates respectively. Optochin and bile solubility (where necessary) tests were done as confirmatory assays for the bacteria. Pneumococci serotyping was done using the Gold Standard Quellung Reaction test while the disk diffusion method was used to asses antibiotic susceptibility profiles. Out of the 206 subjects sampled, 20.39% (n=42) were found to be carriers of the bacteria. About 52% (n=22) of the carriers had received the recommended dose of PCV-10, while 48% (n=20) had not. Almost all (n=41; 19.90% of subjects) isolates contained non-vaccine type serotypes, while n=1 of the isolates (0.49% of subjects) were both optochin resistant and untypeable. Serotypes 28F, 6A, 11A, 3 and 7C were prevalent in both vaccinated and unvaccinated children, whereas serotypes 23A, 17F, 35F, 48, 13 and 35B, and 23B, 20, 19B, 21, untypeable, 15B and 39 were found among unvaccinated and vaccinated cohorts, respectively. Thirty nine (92.86%) of pneumococci isolates were susceptible to erythromycin, 39 (92.86%) were susceptible to vancomycin, 8 (19.86%) were susceptible to oxacillin; 40 (95.24%) were susceptible to clindamycin, 24 (57.86%) were susceptible to ceftriaxone while 18 (42.86%) were non-susceptible. The risk of nasopharyngeal carriage decreased insignificantly when the subject was female (odds ratio [OR]: 0.766, 95% CI: 0.388, 1.511, p-value=0.442). Children between the age of 25-36 months (OR: 1.147 (95% I: 483, 2.722) and 37-48 months (OR: 1, 95% CI: 0.286, 3.501) had an insignificant elevated risk of nasopharyngeal carriage of the bacteria. Children whose mothers were non-cigarrate smokers exhibited low odds of carriage (OR: 0.764 (95% CI: 0.077, 7.537; p=0.818). Serotype replacement, resistance to penicillins and exposure to smoke were correlated with incresaed risk of nasopharyngeal carriage. Continuous and broader epidemiological surveys should be carried out in the entire country to accurately determine the degree of serotype replacement and; people should be sensitised on judicious use and/or consumption of antibiotics. Optochin test should be introduced as a routine assay in diagnosis of Streptococcus pneumoniae in hospitals.