Antibacterial and anti-biofilm activities of probiotic Lactobacillus plantarum against Listeria monocytogenes isolated from milk, chicken and pregnant women

Frontiers in Microbiology

Microbiology

Amira I. Abousaty¹  Nashwa El-Gazzar¹  Asmaa B. M. B. Tahoun²  Reem M. Algendy²  Ibrahim Elsohaby³  Eman A. A. Mohamed⁴  Abdul-Raouf Al-Mohammadi⁵  Rasha M. M. Abou Elez⁶  Marwa Seliem⁶ 

[1] Department of Botany and Microbiology, Faculty of Science, Zagazig University, Zagazig, Egypt;Department of Food Hygiene, Safety and Technology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt;Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR, China;Centre for Applied One Health Research and Policy Advice (OHRP), City University of Hong Kong, Kowloon, Hong Kong SAR, China;Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt;Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt;Department of Science, King Khalid Military Academy, Riyadh, Saudi Arabia;Department of Zoonoses, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt;

关键词: Listeria monocytogenes;    virulotyping;    serotyping;    antimicrobial resistance;    biofilm;    Lactobacillus plantarum;   

DOI  :  10.3389/fmicb.2023.1201201

 received in 2023-04-06, accepted in 2023-07-07,  发布年份 2023

来源: Frontiers

【 摘 要 】

Listeria monocytogenes (L. monocytogenes) is a foodborne pathogen that poses significant risks to public health and food safety. The present study aimed to identify the presence of Listeria spp. in various samples, including pasteurized milk, chicken fillets, and stool samples from pregnant women in Sharkia Governorate, Egypt. Additionally, the study identified the serotypes, virulence-associated genes, antimicrobial resistance patterns, and biofilm formation in L. monocytogenes isolates. Moreover, the antibacterial and anti-biofilm activity of Lactobacillus plantarum ATCC 14917 (L. plantarum) against L. monocytogenes isolates was investigated. A cross-sectional study was conducted from August 2021 to January 2022 to collect 300 samples of pasteurized milk, chicken fillets, and stool from pregnant women admitted to outpatient clinics of hospitals. The results showed that 32.7% of the samples were positive for Listeria spp., including L. innocua (48.9%), L. monocytogenes (26.5%), L. ivanovii (14.3%), L. grayi (5.1%), and L. welshimeri (5.1%). Among all L. monocytogenes isolates, hlyA, actA, inlC, and inlJ virulence-associated genes were detected. However, the virulence genes plcB, iap, and inlA were found in 10 (38.5%), 8 (30.8%), and 25 (96.2%) isolates, respectively. The L. monocytogenes isolates classified into four serotypes (1/2a, 1/2b, 1/2c, and 4b), with 1/2a and 4b each identified in 30.8% of the isolates, while 1/2b and 1/2c were identified in 19.2% of the isolates. All L. monocytogenes isolates showed 100% resistance to streptomycin, kanamycin, and nalidix acid, and 92.3% of isolates showed gentamicin resistance. However, all isolates were susceptible to ampicillin and ampicillin/sulbactam. Multidrug resistance (MDR) was observed in 20 (76.9%) L. monocytogenes isolates. The biofilm formation ability of 26 L. monocytogenes isolates was evaluated at different incubation temperatures. At 4°C, 25°C, and 37°C, 53.8, 69.2, and 80.8% of the isolates, respectively, were biofilm producers. Furthermore, 23.1% were strong biofilm producers at both 4°C and 25°C, while 34.6% were strong biofilm formers at 37°C. Treating L. monocytogenes isolates with L. plantarum cell-free supernatant (CFS) reduced the number of biofilm-producing isolates to 15.4, 42.3, and 53.8% at 4°C, 25°C, and 37°C, respectively. L. plantarum’s CFS antibacterial activity was tested against six virulent, MDR, and biofilm-forming L. monocytogenes isolates. At a concentration of 5 μg/mL of L. plantarum CFS, none of the L. monocytogenes isolates exhibited an inhibition zone. However, an inhibition zone was observed against L. monocytogenes strains isolated from pasteurized milk and pregnant women’s stools when using a concentration of 10 μg/mL. Transmission electron microscopy (TEM) revealed that L. plantarum CFS induced morphological and intracellular structural changes in L. monocytogenes. In conclusion, this study identified virulent MDR L. monocytogenes isolates with strong biofilm-forming abilities in food products in Egypt, posing significant risks to food safety. Monitoring the prevalence and antimicrobial resistance profile of L. monocytogenes in dairy and meat products is crucial to enhance their safety. Although L. plantarum CFS showed potential antibacterial and anti-biofilm effects against L. monocytogenes isolates, further research is needed to explore its full probiotic potential.

【 授权许可】

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Copyright © 2023 Abou Elez, Elsohaby, Al-Mohammadi, Seliem, Tahoun, Abousaty, Algendy, Mohamed and El-Gazzar.