AUTHOR=Li Xin-Xin , Xiao Shu-Zhen , Gu Fei-Fei , Zhao Sheng-Yuan , Xie Qing , Sheng Zi-Ke , Ni Yu-Xing , Qu Jie-Ming , Han Li-Zhong 

TITLE=Serotype Distribution, Antimicrobial Susceptibility, and Multilocus Sequencing Type (MLST) of Streptococcus pneumoniae From Adults of Three Hospitals in Shanghai, China

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=9

YEAR=2019

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2019.00407

DOI=10.3389/fcimb.2019.00407

ISSN=2235-2988

ABSTRACT=<p><bold>Background:</bold><italic>Streptococcus pneumoniae</italic>, a main causative agent associated with invasive and non-invasive infection in elderly population, is a major global health problem. After pneumococcal conjugate vaccines (PCV) and pneumococcal polysaccharide vaccines (PPV) were introduced, the distribution of <italic>S. pneumoniae</italic> serotypes has changed. There was currently limited data on epidemiology and status of antimicrobial resistance of <italic>S. pneumoniae</italic> in Shanghai.</p><p><bold>Objective:</bold> To determine the serotype distribution, antimicrobial susceptibility and molecular epidemiology of <italic>S. pneumoniae</italic> isolated from adults in Shanghai.</p><p><bold>Method:</bold> A total of 75 <italic>S. pneumoniae</italic> isolates consecutively collected from 2015 through 2017 were serotyped by conventional multiplex-PCR. The antimicrobial susceptibility was determined by broth microdilution method. The multilocus sequence type (MLST) was performed to estimate the molecular epidemiology.</p><p><bold>Results:</bold> The predominant serotypes among the isolates were 19F (20.00%), 3 (16.00%), 23F (9.33%), 14 (8.00%), and19A (5.33%). The prevalence of pneumococcal strains with serotypes targeted by vaccines PCV7, PCV10, PCV13, and PPV23 was 44, 45.33, 66.67, and 80%, respectively. Penicillin non-susceptible <italic>S. pneumoniae</italic> (PNSSP) accounted for 16% of the isolates examined and resistance to erythromycin, azithromycin, tetracycline, clindamycin, cefaclor and trimethoprim-sulfamethoxazole were found in 92.00, 90.67, 86.67, 81.33, 54.67, and 54.67% of isolates, with most isolates (78.67%) presenting multidrug-resistance. The top three sequence types (STs) were ST271 (17.33%), ST180 (9.33%), and ST81 (8.00%). The international resistance clone complexes Spain<sup>23F</sup>-1 (<italic>n</italic> = 4), Netherland<sup>3</sup>-31 (<italic>n</italic> = 8), and Taiwan<sup>19F</sup>-14 (<italic>n</italic> = 14) were identified.</p><p><bold>Conclusions:</bold> The <italic>S. pneumoniae</italic> isolates showed high genetic diversity in Shanghai and the prevalence of antimicrobial resistance was also high among <italic>S. pneumoniae</italic> isolates, most of which were multidrug-resistant. The spread of international resistance clones might contribute to the increase of resistant isolates. The PPV23 could protect against most pneumococcal capsular serotypes causing infection of adults in Shanghai.</p>