Serotypes and antibiotic susceptibility of Streptococcus pneumoniae in the Jigme Dorji Wangchuck National Referral Hospital, Thimphu, Bhutan: a preliminary finding

Introduction: Streptococcus pneumoniae cause life-threatening infections, mostly affecting children under five years in developing countries. Several countries in South Asia have incorporated a pneumococcal vaccine in their immunization schedule. Bhutan is currently considering the introduction of a vaccine, although no studies in the country to date have characterized the serotypes of S.pneumoniae to gauge the potential vaccine coverage. We, therefore, characterized pneumococcal serotypes isolated from patients in the Jigme Dorji Wangchuck National Referral Hospital (JDWNRH), Thimphu. Methods: Four hospitals attempted to study S.pneumoniae from various clinical specimens from January 2014 to December 2015, although only the JDWNRH was able to isolate pneumococci. Isolates were tested for antibiotic susceptibility and serotyped at a reference laboratory in India. Results: Thirtyseven isolates were preliminarily identified as S. pneumoniae at the JDWNRH. At the reference laboratory, two isolates could not be revived and 14 were identified as non-pneumococcal streptococci. From the remaining 21 isolates, 15 different serotypes were identified. The Bhutanese serotypes were more comparable to those of India than Bangladesh or Nepal. Current vaccines would cover 26.7% (Prevnar, 7-valent), 40.0% (Synflorix, 10-valent), and 53.3% (Prevnar, 13-valent and Pneumovax23, 23-valent) of these serotypes. All isolates were sensitive to penicillin, chloramphenicol, and ceftriaxone; 9.5% were resistant to erythromycin and 38.1% to cotrimoxazole. Conclusions: For the first time, we characterized serotypes of S. pneumoniae in Bhutan. However, the findings need to be interpreted cautiously due to small numbers of isolates from one referral hospital. A larger study is needed to validate the findings and guide selection of an appropriate vaccine.