Molecular Epidemiology of Streptococcus pneumoniae Detected in Hospitalized Pediatric Acute Respiratory Infection Cases in Central Vietnam

Abstract

Streptococcus pneumoniae is the major bacterial pathogen causing high pneumonia morbidity and mortality in children <5 years of age. This study aimed to determine the molecular epidemiology of S. pneumoniae detected among hospitalized pediatric ARI cases at Khanh Hoa General Hospital, Nha Trang, Vietnam, from October 2015 to September 2016 (pre-PCV). We performed semi-quantitative culture to isolate S. pneumoniae. Serotyping, antimicrobial susceptibility testing, resistance gene detection and multi-locus sequence typing were also performed. During the study period, 1300 cases were enrolled and 413 (31.8%) S. pneumoniae were isolated. School attendance, age <3 years old and prior antibiotic use before admission were positively associated with S. pneumoniae isolation. Major serotypes were 6A/B (35.9%), 19F (23.7%) and 23F (12.7%), which accounted for 80.3% of vaccine-type pneumococci. High resistance to Clarithromycin, Erythromycin and Clindamycin (86.7%, 85%, 78.2%) and the mutant drug-resistant genes pbp1A (98.1%), pbp2b (98.8%), pbp2x (99.6%) ermB (96.6%) and mefA (30.3%) were detected. MLST data showed high genetic diversity among the isolates with dominant ST 320 (21.2%) and ST 13223 (19.3%), which were mainly found in Vietnam. Non-typeables accounted for most of the new STs found in the study. Vaccine-type pneumococcus and macrolide resistance were commonly detected among hospitalized pediatric ARI cases.

High Prevalence of Novel Sequence Types in Streptococcus pneumoniae That Caused Invasive Diseases in Kuwait in 2018

“…In some studies, some STs were found to be dominant. For example, the dominant STs were ST320, ST271, ST81, ST876, and ST3173 in China [ 19 ]; ST179, ST2918, ST386, and ST3772 in Tunisia [ 32 ]; ST320 and ST13223 in Vietnam [ 33 ]; ST618 and ST3081 in the Gambia [ 34 ]; and ST306, ST191, ST989, and ST180 in Spain [ 35 ].…”