Listeria monocytogenes in raw milk, milking equipment and dairy workers: Molecular characterization and antimicrobial resistance patterns. (September 2017)

• Record Type: Journal Article
• Authors: Tahoun, Asmaa B.M.B.; Abou Elez, Rasha M.M.; Abdelfatah, Eman N.; Elsohaby, Ibrahim; El-Gedawy, Attia A.; Elmoslemany, Ahmed M.
• Is Part Of: Journal of global antimicrobial resistance. Volume 10(2017)
• Page Start: 264
• Page End: 270
• Publication Date: 2017-09
• Subjects: Raw milk -- Equipment -- Farm worker -- Listeria monocytogenes -- Antimicrobial resistance; Drug resistance -- Periodicals; Drug resistance -- Periodicals; Drug resistance; Periodicals; 616.9041
• DOI: 10.1016/j.jgar.2017.07.008
• Languages: English
• ISSNs: 2213-7165

Abstract

Highlights: L. monocytogenes are frequently found in raw milk, milking equipment, and farm workers in dairy farms in Egypt. Most virulence genes ( hlyA, prfA, inlA, and inlB ) were highly prevalent in the isolates. ERIC-PCR indicated high genetic relatedness between isolates recovered from raw milk, milking equipment, and farm workers. Resistant to tetracycline and clindamycin was the highest (81%). Susceptibility to ampicillin, levofloxacin, moxifloxacin, linezolid, and tigecycline was high (100%). Abstract: Objectives: The aim of this study was to evaluate the genetic relatedness and patterns of antimicrobial resistance amongst L. monocytogenes isolated from raw milk, milking equipment, and hand swabs from workers in dairy farms. Methods: A total of 300 samples of raw milk, milking equipment, and hand swabs were collected from four dairy farms to examine the presence of Listeria species. Suspected isolates were further identified by VITEK-2 system and Polymerase Chain Reaction (PCR). Antimicrobial susceptibility of the L. monocytogenes isolates was determined, and genotyping analysis was performed by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). Results: Listeria spp. was isolated from 79 (26.3%) of the 300 samples, including 29 (36.7%), 32 (40.5%), and 18 (22.8%) isolates found in raw milk, milking equipment, and hand swabs, respectively. L. monocytogenes was the most common isolated (87.3%) species, while the remaining Listeria isolates were L. innocua (12.7%). Among the 69 L. monocytogenes isolates, 42 (60.8%) showed the mutual presence of hly A, prf A, inl A, and inl B virulence-associated genes. L. monocytogenes isolates from raw milk, milking equipment, and hand swabs showed high genetic relatedness. The potentially virulent L. monocytogenes isolates were most frequently resistance to tetracycline and clindamycin (81%, each) followed by rifampicin (71.4%), whereas, antimicrobial susceptibility was most frequently observed for ampicillin, levofloxacin, moxifloxacin, linezolid, and tigecycline (100%, each). Furthermore, 88% of L. monocytogenes isolates showed multidrug-resistance. Conclusions: The findings of this study show that the contamination of dairy farms with L. monocytogenes is relatively high, and highlight the emergence of multi-drug resistant L. monocytogenes in dairy farms. However, ampicillin is a good choice for treatment of listeriosis in the study area.