scholarly journals Two perspectives of Listeria monocytogenes hazards in dairy products: the prevalence and the antibiotic resistance

2019 ◽  
Author(s):  
Beyza H Ulusoy ◽  
Kefyalew Chirkena
Keyword(s):  
Antibiotic Resistance ◽  
Listeria Monocytogenes ◽  
Dairy Products ◽  
Acquired Resistance ◽  
Raw Milk ◽  
Resistance Mechanisms ◽  
Penicillin G ◽  
Conjugative Transposons ◽  
Food Borne ◽  
Veterinary Importance

Abstract Listeria monocytogenes is among the most food-borne pathogens. It has the ability to grow over a range of temperature, including refrigeration temperature. Foods kept in refrigerator more than the prescribed period of time create an opportunity for the occurrence of Listeria monocytogenes. As this review shows, the prevalence of L. monocytogenes has more likely evident in pasteurized milk than other dairy products, such as raw milk. Inadequate temperature and faults in technology during pasteurization can be the disposing factors for the presence of the organism in dairy products. The organism, on the other hand, has been found to be resistant to those commonly known antibiotics that have human and veterinary importance, namely, ampicillin, Tetracycline, and chloramphenicol, streptomycin, erytromycin, penicillin G., and others. Resistance ability of the organism can be mediated by different natural and acquired resistance mechanisms, such as self-transferrable plasmids, mobilizable plasmids, and conjugative transposons. The emergence and spread of antibiotic resistance of L. monocytogenes has serious public health and economic impacts at large. This paper has reviewed the prevalence and the antibiotic resistance of L. monocytogenes isolates of dairy products and the strategic mechanisms of the organism develop resistance against the antibiotics.

scholarly journals Complex Phenotypic and Genotypic Responses of Listeria monocytogenes Strains Exposed to the Class IIa Bacteriocin Sakacin P

2009 ◽  
Vol 75 (22) ◽  
pp. 6973-6980 ◽  
Author(s):  
Girum Tadesse Tessema ◽  
Trond M�retr� ◽  
Achim Kohler ◽  
Lars Axelsson ◽  
Kristine Naterstad
Keyword(s):  
Listeria Monocytogenes ◽  
Acquired Resistance ◽  
Resistance Mechanisms ◽  
Gene Encoding ◽  
Genetic Characteristics ◽  
Food Borne ◽  
Resistant Strains ◽  
Resistant Mutants ◽  
Related Stress ◽  
The Stability

ABSTRACT Sakacin P is a class IIa bacteriocin that is active against the food-borne pathogen Listeria monocytogenes, and use of this compound as a biopreservative in foods has been suggested. In the present study, we characterized 30 spontaneous sakacin P-resistant mutants of L. monocytogenes obtained after single exposure to sakacin P. The frequency of development of sakacin P resistance for all strains was in the range from 10−8 to 10−9. Using the 50% inhibitory concentration (IC50) of sakacin P, the strains could be grouped into strains with high levels of resistance (IC50, ≥104 ng ml−1) and strains with low levels of resistance (IC50, <104 ng ml−1). Resistant strains belonging to the same IC50 group also had similar physiological and genetic characteristics. Generally, the resistant strains showed substantial variations in many parameters, such as differences in the stability of the acquired resistance to sakacin P, growth fitness, food-related stress tolerance, and biofilm-forming ability. Fourier transform infrared spectroscopy revealed differences between wild-type and resistant strains in polysaccharide, fatty acid, and, protein regions. A mannose-specific phosphotransferase (PTS) operon has been described for class IIa bacteriocin resistance, and the sakacin P-resistant strains displayed both up- and downregulation of the expression of the mptA gene encoding the PTS system. This is the first comprehensive study of the diversity of a large number of spontaneous resistant mutants obtained after one exposure to a class IIa bacteriocin, particularly to sakacin P. The great diversity among the resistant strains exposed to the same stress conditions suggests that there are different resistance mechanisms.

scholarly journals Listeria monocytogenes: An emerging food-borne pathogen and its public health implications

2016 ◽  
Vol 10 (02) ◽  
pp. 149-154 ◽  
Author(s):  
Waffa W Reda ◽  
Khaled Abdel-Moein ◽  
Ahmed Hegazi ◽  
Yasmin Mohamed ◽  
Khaled Abdel-Razik
Keyword(s):  
Listeria Monocytogenes ◽  
Raw Milk ◽  
Food Samples ◽  
Food Borne ◽  
Contaminated Food ◽  
Luncheon Meat ◽  
Stool Specimens ◽  
Polymerase Chain ◽  
Minced Meat

Introduction: Listeria monocytogenes is considered one of the most important food-borne pathogens transmitted to humans via contaminated food. The aim of the present study was to demonstrate the importance of L. monocytogenes as a food-borne pathogen. Methodology: A total of 340 samples were collected from different localities in El Giza Governorate, Egypt, to check the occurrence of L. monocytogenes in that area. The collected samples comprised 250 food samples, 40 swabs from food refrigerators, and 50 stool specimens from diarrheic children. L. monocytogenes was isolated from the examined samples according to the International Organization for Standardization. The isolates were tested biochemically using Listeria Microbact 12L and confirmed by polymerase chain reaction. Results: The isolation rates of L. monocytogenes were 8% in beef burger, 4% in minced meat, 4% in luncheon meat, while sausage samples were all negative. Eight percent of raw milk samples were positive for L. monocytogenes, whereas cheese samples and refrigerator swabs were negative. Only Listeria grayi was isolated from human stools (2.5%). Conclusion: The high isolation rates of L. monocytogenes among the examined food stuffs highlight the crucial role of food as an important vehicle for this pathogen. More efforts should be made to ensure safe handling and processing of these foods to reduce the transmission of L. monocytogenes to humans.

Occurrence of Listeria monocytogenes in Milk and Dairy Products Produced or Imported Into Morocco

1993 ◽  
Vol 56 (3) ◽  
pp. 256-259 ◽  
Author(s):  
A. EL MARRAKCHI ◽  
A. HAMAMA ◽  
F. EL OTHMANI
Keyword(s):  
Listeria Monocytogenes ◽  
Dairy Products ◽  
Raw Milk ◽  
Listeria Innocua ◽  
Pasteurized Milk ◽  
Listeria Species ◽  
Fresh Cheese ◽  
Milk And Dairy Products

Examination of 227 samples of milk and dairy products for Listeria monocytogenes showed that raw milk and some Moroccan traditionally made dairy products such as Iben and raib (fermented milks) and jben (fresh cheese) were contaminated with this pathogen. L. monocytogenes was the only Listeria species isolated except in one case in which it was associated with Listeria innocua. Pasteurized milk, fresh cream, and fresh and ripened cheeses (industrially made) were free from L. monocytogenes.

Comparison of EB and Fraser Enrichment Broths for the Detection of Listeria spp. and Listeria monocytogenes in Raw-Milk Dairy Products and Environmental Samples

1996 ◽  
Vol 59 (11) ◽  
pp. 1172-1175 ◽  
Author(s):  
GEERTRUI M. VLAEMYNCK ◽  
RENAAT MOERMANS
Keyword(s):  
Listeria Monocytogenes ◽  
Dairy Products ◽  
Raw Milk ◽  
Chain Reaction ◽  
Enrichment Broth ◽  
Selective Enrichment ◽  
Isolation Frequency ◽  
Detection And Identification ◽  
Significant Difference ◽  
Polymerase Chain

This study is a comparison of the isolation frequency of Listeria spp. and Listeria monocytogenes from selected naturally contaminated dairy products, especially soft smear-ripened cheeses from raw milk and samples of feces and rinse samples from the udder taken on the farm, by using an enrichment broth (EB) recommended by the International Dairy Federation and the U.S. Food and Drug Administration (IDF and FDA) or Fraser broth as the selective enrichment. Detection and identification were carried out according to the IDF protocols and a polymerase chain reaction technique. Listeria spp. were detected in 39.8% of the 570 samples while 15.3% were positive for L. monocytogenes. For cheese and curd samples, Fraser enrichment broth gave a statistically significant higher recovery for all Listeria spp. (26 to 21 %) as well as for L. monocytogenes in particular (9 to 1.4%). For raw milk and samples taken from feces and the udder rinse no significant difference was found between EB and Fraser broth. A combination of both enrichments resulted in an increase of recovery over all matrices by 15%.

scholarly journals Molecular Characterization of Shiga Toxin-ProducingEscherichia coliIsolated from Ruminant and Donkey Raw Milk Samples and Traditional Dairy Products in Iran

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Hassan Momtaz ◽  
Rahil Farzan ◽  
Ebrahim Rahimi ◽  
Farhad Safarpoor Dehkordi ◽  
Negar Souod
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Shiga Toxin ◽  
Dairy Products ◽  
Antibiotic Resistance Genes ◽  
Culture Method ◽  
Raw Milk ◽  
Antibiotics Resistance ◽  
E Coli ◽  
Pathogenic Genes

The aims of the current study were to detect the virulence factors and antibiotic resistance of Shiga toxin-producingE. coli, in animal milk and dairy products in Iran. AfterE. colidentification with culture method, PCR assay were developed for detection of pathogenic genes, serotypes and antibiotic resistance genes ofE. coli. Results showed that out of 719 samples, 102 (14.18%) were confirmed to be positive forE. coliand out of 102 positive samples, 17.64% were O26 and 13.72% were O157 and 1.96% were O91 and 1.96% were O145 serotypes. Totally, the prevalence ofstx1 andpapAgenes were the highest while the prevalence ofsfaSandfyuAwere the lowest in the positive samples. PCR results showed thattetA, tetBwere the highest (64.70%) andaac(3)-IVwere the lowest (27.45%) antibiotic resistant genes inE. colipositive samples. Our study indicated that the isolatedE. colitrains in these regions had a highest antibiotic resistance to tetracycline (58.82%) and the lowest to nitrofurantoin (3.92%).tetAgene andE. coliO157 serotype had highest andaac(3)-IVgene, andE. coliO145 serotype had a lowest frequency rates of antibiotics resistance genes, in the region.

Assessing and analysing contamination of a dairy products processing plant byStaphylococcus aureususing antibiotic resistance and PFGE

2000 ◽  
Vol 46 (12) ◽  
pp. 1108-1114 ◽  
Author(s):  
E C Tondo ◽  
MC M Guimarães ◽  
J AP Henriques ◽  
M AZ Ayub
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Antibiotic Susceptibility ◽  
Dairy Products ◽  
Dairy Product ◽  
Raw Milk ◽  
Food Handler ◽  
Processing Plant ◽  
Pfge Analysis ◽  
Antibiotic Susceptibility Test

A dairy product processing plant was studied for 2.5 years to examine contamination with Staphylococcus aureus and try to correlate the source of contamination. Cultures were submitted to an antibiotic susceptibility test (AST) and characterised by Pulsed-field Gel Electrophoresis (PFGE) analysis. Results showed that 35.2% (19/51) of food handlers were asymptomatic carriers of S. aureus, and that 90.4% (19/21) of raw milk sampled was contaminated. Staphylococcus aureus was isolated from only 10 samples among more than 3200 investigated dairy products. No S. aureus contamination was found on machinery. The AST analysis demonstrated sensitivity of tested S. aureus to oxacillin, cephalothin, vancomycin, gentamicin, and sulfamethoxazole/trimethoprim. AST analysis generated eight different phenotypic profiles, but did not allow us to identify the source of contamination in seven of ten final products. PFGE analysis proved to be a sensitive method as it generated 42 different DNA banding profiles among the 48 S. aureus investigated, demonstrating a lack of predominance of endemic strains in the plant, contrary to suggestions raised by antibiotic resistance typing. Based on PFGE genotyping, S. aureus strains isolated from four contaminated final products were similar to four S. aureus isolated from raw milk. Five final products contained S. aureus different from all other strains collected, and one showed similarity to a strain isolated from a food handler. These results suggest contamination by raw milk as the main source of contamination of the final dairy products.Key words: Staphylococcus aureus, dairy products, antibiotic susceptibility, PFGE.

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