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Start Over Author "Chen, Mingliang" Journal frontiers in microbiology
7 results on '"Chen, Mingliang"'

2. Virulence and Stress Responses of Shigella flexneri Regulated by PhoP/PhoQ

Author

Xiaofei Wang, Zhiwei Lin, Zhihui Lv, Xia Cai, Di Qu, Yang Wu, Lina Ye, Yongpeng Shang, and Chen Mingliang

Subjects
0301 basic medicine, Microbiology (medical), PhoP/PhoQ, Operon, 030106 microbiology, lcsh:QR1-502, Virulence, Mg2+, medicine.disease_cause, Microbiology, Virulence factor, lcsh:Microbiology, 03 medical and health sciences, Shigella flexneri, icsA, medicine, Shigella, S. flexneri, Sereny test, biology, two-component signal transduction system, Chemistry, biochemical phenomena, metabolism, and nutrition, biology.organism_classification, virulence, bacteria, Bacteria, Polymyxin B, medicine.drug
Abstract

The two-component signal transduction system PhoP/PhoQ is an important regulator for stress responses and virulence in most Gram-negative bacteria, but characterization of PhoP/PhoQ in Shigella has not been thoroughly investigated. In the present study, we found that deletion of phoPQ (ΔphoPQ) from Shigella flexneri 2a 301 (Sf301) resulted in a significant decline (reduced by more than 15-fold) in invasion of HeLa cells and Caco-2 cells, and less inflammation (- or +) compared to Sf301 (+++) in the guinea pig Sereny test. In low Mg2+ (10 μM) medium or pH 5 medium, the ΔphoPQ strain exhibited a growth deficiency compared to Sf301. The ΔphoPQ strain was more sensitive than Sf301 to polymyxin B, an important antimicrobial agent for treating multi-resistant Gram-negative infections. By comparing the transcriptional profiles of ΔphoPQ and Sf301 using DNA microarrays, 117 differentially expressed genes (DEGs) were identified, which were involved in Mg2+ transport, lipopolysaccharide modification, acid resistance, bacterial virulence, respiratory, and energy metabolism. Based on the reported PhoP box motif [(T/G) GTTTA-5nt-(T/G) GTTTA], we screened 38 suspected PhoP target operons in S. flexneri, and 11 of them (phoPQ, mgtA, slyB, yoaE, yrbL, icsA, yhiWX, rstA, hdeAB, pagP, and shf-rfbU-virK-msbB2) were demonstrated to be PhoP-regulated genes based on electrophoretic mobility shift assays and β-galactosidase assays. One of these PhoP-regulated genes, icsA, is a well-known virulence factor in S. flexneri. In conclusion, our data suggest that the PhoP/PhoQ system modulates S. flexneri virulence (in an icsA-dependent manner) and stress responses of Mg2+, pH and antibacterial peptides.

Published
2018

3. Identification and Characterization of Fluoroquinolone Non-susceptible Streptococcus pyogenes Clones Harboring Tetracycline and Macrolide Resistance in Shanghai, China

Author

Shen, Yinfang, primary, Cai, Jiehao, additional, Davies, Mark R., additional, Zhang, Chi, additional, Gao, Kun, additional, Qiao, Dan, additional, Jiang, Haoqin, additional, Yao, Weilei, additional, Li, Yuefang, additional, Zeng, Mei, additional, and Chen, Mingliang, additional

Published
2018
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7. An emm 5 Group A Streptococcal Outbreak Among Workers in a Factory Manufacturing Telephone Accessories.

Author

Chen M, Wang W, Tu L, Zheng Y, Pan H, Wang G, Chen Y, Zhang X, Zhu L, Chen J, and Chen M

Abstract

Ranked among the top10 infectious causes of death worldwide, group A Streptococcus (GAS) causes small- and large-scale outbreaks, depending on the trigger as transmission of a GAS strain or expansion of predominant clones. In China, GAS infections other than scarlet fever are not notifiable. In Shanghai, an epidemiological investigation was initiated after two successive severe pneumonia cases with one death in a digital factory, from where outbreaks are less widely reported. The investigation was performed using emm typing, pulsed-field gel electrophoresis (PFGE) typing, superantigen profiling, and genome analysis. This enabled characterization of relatedness among the outbreak isolates and identification of the mobile genetic elements present. Among 57 patients with respiratory symptoms investigated in the factory, emm 5 GAS strains were isolated from 8 patients. The eight GAS infection cases comprising one fatal severe pneumonia case, six influenza-like illness cases, and one pharyngitis case. Two risk factors were identified: adult with an age of 18-20 years and close contact with a GAS patient or carrier. GAS attack rate was 14.0% (8/57), and GAS carriage rate was probably around 2.7% (14/521) based on surveys in two nearby districts. All the 10 outbreak associated isolates were assigned to emm 5 and sequence type ST-99 ( emm 5/ST-99), harbored superantigen genes speC, speG , and smeZ , and were assigned to two similar PFGE patterns (clones). Among the outbreak associated isolates, all carried ermA with resistance to erythromycin and inducible resistance to clindamycin, and eight (80%) carried a tetM gene with resistance to tetracycline. Among the 14 carriage isolates, 12 were emm 12/ST-36, and 2 were emm 1/ST-28, all with superantigen genes speC, speG, ssa , and smeZ . All the carriage isolates harbored ermB and tetM with resistance to erythromycin, clindamycin, and tetracycline. Genome analysis showed the two outbreak clones were closely related and possessed new prophages carrying virulence gene sdc and antibiotic resistance genes of ermA and tetM , which were not found in the emm 5 reference strain Manfredo. This is the first report of a GAS outbreak in this type of workplace. The outbreak was caused by two closely related emm 5 clones that differed from the predominant emm types circulating in China.

Published
2017
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