Isolation, Potential Virulence, and Population Diversity of Listeria monocytogenes From Meat and Meat Products in China

Moutong Chen; Jianheng Cheng; Jumei Zhang; Yuetao Chen; Haiyan Zeng; Liang Xue; Tao Lei; Rui Pang; Shi Wu; Haoming Wu; Shuhong Zhang; Xianhu Wei; Youxiong Zhang; Yu Ding; Qingping Wu

doi:10.3389/fmicb.2019.00946

Isolation, Potential Virulence, and Population Diversity of Listeria monocytogenes From Meat and Meat Products in China

Front Microbiol. 2019 May 7:10:946. doi: 10.3389/fmicb.2019.00946. eCollection 2019.

Authors

Moutong Chen¹, Jianheng Cheng¹, Jumei Zhang¹, Yuetao Chen^{1

2}, Haiyan Zeng¹, Liang Xue¹, Tao Lei¹, Rui Pang¹, Shi Wu¹, Haoming Wu¹, Shuhong Zhang¹, Xianhu Wei¹, Youxiong Zhang¹, Yu Ding³, Qingping Wu¹

Affiliations

¹ Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Open Laboratory of Applied Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangzhou, China.
² College of Food Science, South China Agricultural University, Guangzhou, China.
³ Department of Food Science and Technology, Jinan University, Guangzhou, China.

Abstract

Listeria monocytogenes is a globally notorious foodborne pathogen. This study aimed to qualitatively and quantitatively detect L. monocytogenes from meat and meat products in China and to establish their virulence profiles and population diversity. From 1212 meat and meat product samples, 362 (29.9%) were positive for L. monocytogenes. Of these positive samples, 90.6% (328/362) had less than 10 MPN/g, 5.5% (20/364) samples had 10-110 MPN/g, and 3.9% (14/362) of the positive samples had over 110 MPN/g. Serogroup analysis showed that the most prevalent serogroup of L. monocytogenes was I.1 (1/2a-3a), which accounted for 45.0% (123/458) of the total, followed by serogroup I.2 (1/2c-3c) that comprised 26.9%, serogroup II.1 (4b-4d-4e) that comprised 4.8%, and serogroup II.2 (1/2b-3b-7) that comprised 23.3%. A total of 458 isolates were grouped into 35 sequence types (STs) that belonged to 25 clonal complexes (CCs) and one singleton (ST619) by multi-locus sequence typing. The most prevalent ST was ST9 (26.9%), followed by ST8 (17.9%), ST87 (15.3%), ST155 (9.4%), and ST121 (7.6%). Thirty-seven isolates harbored the llsX gene (representing LIPI-3), and they belonged to ST1/CC1, ST3/CC3, ST288/CC288, ST323/CC288, ST330/CC288, ST515/CC1, and ST619, among which ST323/CC288, ST330/CC288, and ST515/CC1 were newly reported to carry LIPI-3. Seventy-five isolates carried ptsA, and they belonged to ST87/CC87, ST88/CC88, and ST619, indicating that consumers may be exposed to potential hypervirulent L. monocytogenes. Antibiotics susceptibility tests revealed that over 90% of the isolates were susceptible to 11 antibiotics; however, 40.0% of the isolates exhibited resistance against ampicillin and 11.8% against tetracycline; further, 45.0 and 4.6% were intermediate resistant and resistant to ciprofloxacin, respectively. The rise of antibiotic resistance in L. monocytogenes suggests that stricter regulations should be formulated to restrict the use of antibiotic agents in human listeriosis treatment and livestock breeding.

Keywords: LIPI-3; LIPI-4; Listeria monocytogenes; animal-derived food products; antibiotic resistance; multi-locus sequence typing.