header
Image from OpenLibrary

Prevalence and transmissibility of antimicrobial resistance genes in heat treated milk / Eman Mostafa Salah Mohamed Taher ; Supervised Hamdy A. Elesawy , Salwa A. Aly , Kiro R. Petrovski

By: Contributor(s): Material type: TextTextLanguage: English Publication details: Cairo : Eman Mostafa Salah Mohamed Taher , 2020Description: 107 P . : charts , facsimiles ; 25cmOther title:
  • تواجد وانتقال الجينات المقاومة لمضادات الميكروبات فى اللبن المعالج حراريا [Added title page title]
Subject(s): Available additional physical forms:
  • Issued also as CD
Dissertation note: Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Food Hygiene and Control Summary: This study investigated the persistence and quantification of blaZ, mecC and tetK plasmid-mediated ARGs copy numbers of two staphylococcal strains in both milk and Tris - EDTA (TE) buffer over 3 weeks storage on refrigeration +4oC. During subsequent storage after pasteurization, all tested genes showed increased copy numbers. By electroporation of these genes to the Staphylococcus aureus RN42200 electro-competent strain, both mecC and tetK genes were still expressive and transferable. The formation of VBNC cells was estimated with viability staining and quantitative PCR of 16S rDNA copy numbers of both staphylococcal strains. On the other hand, surveying the prevalence of nine plasmid-mediated and one genomic AMR genes in 100 (50 bulk tank milk & 50 milk filters socks) samples at farm level and 152 (84 pasteurized and 68 ultra-heat-treated milk) commercial samples, results revealed that sul2 gene was the most prevalent plasmid-mediated gene in (96%) milk filters socks, (48%) bulk tank milk, (68%) pasteurized and (43%) UHT samples; on contrary the mecA gene could not be detected in any sample. Moreover, currently practiced commercial pasteurization not only failed to decrease the prevalence of the bla-TEM-B1 (43%), tetK (30%) and tetA (55%) plasmid-mediated AMR genes, but also potentially stimulates dairy microbiota to enter into a viable but non-culturable (VBNC) state. In contrast, after the sterilization treatment all the genes showed decreases in copy numbers, and viability assessment showed that UHT treatment is less to induce VBNC state. Continued research is necessary to identify bacterial species entering the VBNC state after pasteurization, assess their potential resuscitation hazard level, and shed more light on the expression and possibility of horizontal gene transfer of those plasmid-mediated AMR genes to gut microbiota
Tags from this library: No tags from this library for this title. Log in to add tags.
Star ratings
    Average rating: 0.0 (0 votes)
Holdings
Item type Current library Home library Call number Copy number Status Date due Barcode
Thesis Thesis قاعة الرسائل الجامعية - الدور الاول المكتبة المركزبة الجديدة - جامعة القاهرة Cai01.10.06.Ph.D.2020.Em.P (Browse shelf(Opens below)) Not for loan 01010110082222000
CD - Rom CD - Rom مخـــزن الرســائل الجـــامعية - البدروم المكتبة المركزبة الجديدة - جامعة القاهرة Cai01.10.06.Ph.D.2020.Em.P (Browse shelf(Opens below)) 82222.CD Not for loan 01020110082222000

Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Food Hygiene and Control

This study investigated the persistence and quantification of blaZ, mecC and tetK plasmid-mediated ARGs copy numbers of two staphylococcal strains in both milk and Tris - EDTA (TE) buffer over 3 weeks storage on refrigeration +4oC. During subsequent storage after pasteurization, all tested genes showed increased copy numbers. By electroporation of these genes to the Staphylococcus aureus RN42200 electro-competent strain, both mecC and tetK genes were still expressive and transferable. The formation of VBNC cells was estimated with viability staining and quantitative PCR of 16S rDNA copy numbers of both staphylococcal strains. On the other hand, surveying the prevalence of nine plasmid-mediated and one genomic AMR genes in 100 (50 bulk tank milk & 50 milk filters socks) samples at farm level and 152 (84 pasteurized and 68 ultra-heat-treated milk) commercial samples, results revealed that sul2 gene was the most prevalent plasmid-mediated gene in (96%) milk filters socks, (48%) bulk tank milk, (68%) pasteurized and (43%) UHT samples; on contrary the mecA gene could not be detected in any sample. Moreover, currently practiced commercial pasteurization not only failed to decrease the prevalence of the bla-TEM-B1 (43%), tetK (30%) and tetA (55%) plasmid-mediated AMR genes, but also potentially stimulates dairy microbiota to enter into a viable but non-culturable (VBNC) state. In contrast, after the sterilization treatment all the genes showed decreases in copy numbers, and viability assessment showed that UHT treatment is less to induce VBNC state. Continued research is necessary to identify bacterial species entering the VBNC state after pasteurization, assess their potential resuscitation hazard level, and shed more light on the expression and possibility of horizontal gene transfer of those plasmid-mediated AMR genes to gut microbiota

Issued also as CD

There are no comments on this title.

to post a comment.