Occurrence, Antibiotic Resistance, and Population Diversity of Listeria monocytogenes Isolated From Fresh Aquatic Products in China

Abstract

Listeria monocytogenes is an important Gram-positive foodborne pathogen. However, limited information is available on the comprehensive investigation and potential risk of L. monocytogenes in fresh aquatic products, which are popular to consumers in China. This study aimed to determine the occurrence, virulence profiles, and population diversity of L. monocytogenes isolated from aquatic products in China. In total, 846 aquatic product samples were collected between July 2011 and April 2016 from 43 cities in China. Approximately 7.92% (67/846) aquatic product samples were positive for L. monocytogenes, 86.57% positive samples ranged from 0.3 to 10 MPN/g, whereas 5.97% showed over 110 MPN/g by the Most Probable Number method, which included two samples of products intended to be eaten raw. Serogroups I.1 (serotype 1/2a), I.2 (serotype 1/2b), and III (serotype 4c) were the predominant serogroups isolated, whereas serogroup II.1 (serotype 4b) was detected at much lower frequencies. Examination of antibacterial resistance showed that nine antibacterial resistance profiles were exhibited in 72 isolates, a high level susceptibility of 16 tested antibiotics against L. monocytogenes were observed, indicating these common antibacterial agents are still effective for treating L. monocytogenes infection. Multilocus sequence typing revealed that ST299, ST87, and ST8 are predominant in aquatic products, indicating that the rare ST299 (serotype 4c) may have a special ecological niche in aquatic products and associated environments. Except llsX and ptsA, the 72 isolates harbor nine virulence genes (prfA, actA, hly, plcA, plcB, iap, mpl, inlA, and inlB), premature stop codons (PMSCs) in inlA were found in four isolates, three of which belonged to ST9. A novel PMSC was found in 2929-1LM with a nonsense mutation at position 1605 (TGG→TGA). All ST87 isolates harbored the ptsA gene, whereas 8 isolates (11.11%) carried the llsX gene, and mainly belonged to ST1, ST3, ST308, ST323, ST330, and ST619. Taken together, these results first reported potential virulent L. monocytogenes isolates (ST8 and ST87) were predominant in aquatic products which may have implications for public health in China. It is thus necessary to perform continuous surveillance for L. monocytogenes in aquatic products in China.

Prevalence, Pathogenicity, Virulence, Antibiotic Resistance, and Phylogenetic Analysis of Biofilm-Producing Listeria monocytogenes Isolated from Different Ecological Niches in Egypt: Food, Humans, Animals, and Environment

“…The absence of genes encoding the inlC or inlJ in only four of the isolates suggests a L. monocytogenes population with potentially diverse markers associated with infectivity. L. monocytogenes isolates from imported frozen fish lacked the four main internalin genes (inlA, inlB, inlC, and inlJ) in contrast to the previous studies, where internalin genes were present in almost all previously examined L. monocytogenes isolates from all 4 niches-humans, animals, food, and environment [46][47][48][70][71][72][73][74][75][76][77][78].…”

“…Globally, the prevalence rates in fish show great variability [3,25,44,[46][47][48][49]: The prevalence of L. monocytogenes in fish are presumably from contaminated waters or during manipulation and processing with contaminated environment and/or equipment [47,50]. The L. monocytogenes isolated from our frozen fish samples indicates that L. monocytogenes has the ability to endure freezing of food, thereby acting as a reservoir to participate in future human listerial outbreaks [9,25,[51][52][53].…”

“…monocytogenes exhibiting resistance to antibiotics commonly used for the treatment of listeriosis, including ampicillin and other penicillins, and gentamicin resulting in treatment failure, are of major concern [79]. While antibiotic resistance of L. monocytogenes isolates from food, the environment, and human have been reported during the present decade [49], differences between the phenotypic antibiotic resistance of isolates from different ecological niches appear to vary by antimicrobial usage in humans and animals of different geographical location [3,46,50,80]. The isolates in this study showed sensitivity to antibiotics within the penicillin class, second generation fluoroquinolones, glucopeptide class, and rifampicin, while showing complete resistance to phenicols, polypeptides, and lincosamides.…”

Immunoinformatics Prediction of Epitope Based Peptide Vaccine Against Listeria Monocytogenes Fructose Bisphosphate Aldolase Protein

“…The disease includes, but not limited to sepsis, meningitis, encephalitis, spontaneous abortion, or fever and self-limiting gastroenteritis in a healthy adult [2]. Food-borne listeriosis has a global economic and health burden due to the wide spread of Listeria Monocytogenes in food and food processing environments [4]. It capable of proliferating in different stressful environmental conditions, including high salinity, low temperature (refrigerator), and a wide range of pH values [4].…”

“…Food-borne listeriosis has a global economic and health burden due to the wide spread of Listeria Monocytogenes in food and food processing environments [4]. It capable of proliferating in different stressful environmental conditions, including high salinity, low temperature (refrigerator), and a wide range of pH values [4]. Although the incidence of listeriosis is relatively rare compared to other food-borne illnesses, listeriosis accounts for approximately 19% of deaths among all food-borne illness [5].…”