Prevalence of Listeria monocytogens in Farm Milk and Some Dairy Products with Comparing its Sensitivity to Different Antibiotics and H2O2 Loaded on Silver Nanoparticles in Dakahlia Governorate, Egypt.

Abstract

L. monocytogens is one of the major food-borne pathogens which can affect humans and a wide variety of animal species. It usually invades Milk and its products at several steps in the food chain, Listeriosis outbreaks remain an important problem globally. High resistance of L. monocytogens to the most of antibiotics due to misusing of it in both veterinary and human field, it necessitates searching about alternatives. Drug laden nanoparticles possibly will overwhelm the restrictions of conservative antibiotic actions related with poisonousness, unsuitable distribution, or enzymatic dilapidation. The aim of this research is to detect prevalence of this bacteria in farm milk and some milk products and to mark the result of H2O2 loaded on silver nanoparticles on Multidrug resistance strains of L. monocytogenes. Therefore, One hundred samples (25 farm bulk tank, 25 plain yoghurt and 50 fresh soft cheese (Talaga)) were haphazardly composed from dairy farms and different shops in different areas of Mansoura city, Dakahlia governorate. Egypt. The isolated strains of L. monocytogenes were evaluated phenotypically and genotypically for detection of virulence factors (invasive linked protein (iap), haemolysin (hylA) and actin polymerization protein (actA)) that were carried out by using multiplex PCR. Out of 100 samples 7 listeria monocytogenes isolates from Fresh soft cheese (Talaga) samples (14%). These 7 isolates had iap gene, while 6 isolates had hly gene and 5 isolates had actA gene. Also the three types of virulence genes were in four isolates at which a higher multiple antibiotic resistance between L.monocytogenes isolates. Assessment of antibacterial action of silver nanoparticles and hydrogen peroxide Antibacterial doings was assessed by broth micro-dilution test and our results revealed that H2O2/AgNPs with 6.25-3.13 µg/mL MIC values of the original concentrations 13 µg/mL MIC values of the original concentrations highly effective against L. monocytogens.