Assessment of the Prevalence and Drug Susceptibility of Listeria monocytogenes Strains Isolated from Various Types of Meat

Abstract

Listeria monocytogenes are the etiological factor of listeriosis, and their main source for humans is food. The aim of the current study was to assess the contamination of various types of meat and the drug susceptibility of isolated L. monocytogenes. Between 2016–2018, 6000 swabs were taken (2000 annually) from the surface of pork, beef, and poultry. The analysis of intermediate and finished product samples was carried out in accordance with ISO 11290-1 (International Organization for Standardization). The genetic similarity assessment of the isolates obtained was based on the Pulsed Field Gel Electrophoresis (PFGE) method, and drug-sensitivity assessment using the disc-diffusion method. We found 2.1% of collected samples were L. monocytogenes positive. The level of meat contamination varied depending on its matrix. Most L. monocytogenes were isolated from poultry. It was shown that 39 (32.5%) strains were sensitive to all tested antibiotics and eight (6.7%) were resistant to all five tested antimicrobials. Most strains tested were resistant to cotrimoxazole (55; 45.8%) and meropenem (52; 43.3%), followed by erythromycin (48; 40.0%), penicillin (31; 25.8%), and ampicillin (21; 17.5%). High prevalence of this pathogen may be a serious problem, especially when linked with antibiotic resistance and high percentage of serotypes responsible for listeriosis outbreaks.

Antibiotic Resistance in Bacteria—A Review

“…One of the latest studies, analysing drug resistance among 120 L. monocytogenes strains isolated in Poland [ 180 ] from a total of 6000 samples from pigs, cattle, and poultry, confirmed resistance to cotrimoxazole (45.8%), meropenem (43.3%), erythromycin (40.0%), penicillin (25.8%), and ampicillin (17.5%), with a high level of multi-drug resistance. In Germany [ 181 ], among 259 L. monocytogenes strains isolated from food and processing environments and samples from patients, as many as 145 strains revealed multidrug resistance (resistance to ≥3 antibiotics).…”

Prevalence and antimicrobial susceptibility of Listeria monocytogenes strains isolated from a meat processing plant

“…An important issue significantly affecting determination of the proper sanitary procedures, and thus the reduction of cross-contamination, is the assessment of genetic similarity between strains isolated within a processing plant. Martin et al [29], analyzing 18 meat plants, detected persistent strains of L. monocytogenes (106 isolates) in the raw material, RTE products and food contact surfaces. In this study, RAPD-PCR confirmed the presence of the same genotype on the floor of the smokehouse at an interval of 2 months.…”

Listeria monocytogenes Isolates from Meat Products and Processing Environment in Poland Are Sensitive to Commonly Used Antibiotics, with Rare Cases of Reduced Sensitivity to Ciprofloxacin

“…The method typically applied by authors to determine antibiotic resistance of L. monocytogenes is disc diffusion [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ], with differences in the procedures such as exact antibiotics used in the study, the content of the antibiotic in impregnated discs, divergent media, and varying incubation conditions. What is more, authors often decide to apply different criteria for interpreting the results of their experiments in terms of classifying particular strains as resistant, intermediate, or sensitive to antibiotics.…”