AUTHOR=Li Xin-Xin , Xiao Shu-Zhen , Gu Fei-Fei , He Wei-Ping , Ni Yu-Xing , Han Li-Zhong 

TITLE=Molecular Epidemiology and Antimicrobial Resistance of Haemophilus influenzae in Adult Patients in Shanghai, China

JOURNAL=Frontiers in Public Health

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2020.00095

DOI=10.3389/fpubh.2020.00095

ISSN=2296-2565

ABSTRACT=<p><bold>Background:</bold> The serotype and antimicrobial resistance of <italic>Haemophilus influenzae</italic> in adult patients have changed due to the application of antimicrobials and <italic>H. influenzae</italic> type b (Hib) vaccine worldwide. However, the epidemiologic characteristics of <italic>H. influenzae</italic> in Shanghai are still unavailable.</p><p><bold>Objective:</bold> To determine the serotype distribution, antimicrobial resistance and multilocus sequence type (MLST) of <italic>H. influenzae</italic> in adult patients in Shanghai.</p><p><bold>Methods:</bold> A total of 51 clinical isolates from adult patients were consecutively collected. Serotypes were determined according to specific capsule gene, <italic>bexA</italic>, amplified by PCR. Antimicrobial susceptibility test was carried out by the broth microdilution method. β-lactamase production was detected by cefinase disk and the <italic>ftsI</italic> gene were amplified and sequenced to determine the penicillin binding protein 3 (PBP3) mutation. Molecular epidemiology was performed by MLST analyses.</p><p><bold>Results:</bold> All isolates studied were nontypeable <italic>H. influenzae</italic> (NTHi) and three of them (5.88%) caused invasive infection. The resistant rates of ampicillin and trimethoprim/sulfamethoxazole were both 45.10%. One third of these isolates produced TEM-1 type β-lactamase and 11.76% were β-lactamase negative ampicillin resistant strains (BLNAR). The PBP3 mutation was detected in 74.51% of the isolates, of which 12 belonged to group III. A total of 36 sequence types (STs) were identified among all isolates. Four isolates of ST103 (7.84%) all produced β-lactamase without mutation of PBP3.</p><p><bold>Conclusion:</bold><italic>H. influenzae</italic> infections among adults in Shanghai are predominately caused by NTHi with genetic diversity among adult patients. The prevalence of both β-lactamase production and PBP3 mutation may contribute to high ampicillin resistance rate in Shanghai.</p>