Antimicrobial Resistance Profiles ofListeria monocytogenesandListeria innocuaIsolated from Ready-to-Eat Products of Animal Origin in Spain

Abstract

The objective of this work was to investigate the antimicrobial resistance in Listeria spp. isolated from food of animal origin. A total of 50 Listeria strains isolated from meat and dairy products, consisting of 7 Listeria monocytogenes and 43 Listeria innocua strains, were characterized for antimicrobial susceptibility against nine antimicrobials. The strains were screened by real-time PCR for the presence of antimicrobial resistance genes: tet M, tet L, mef A, msr A, erm A, erm B, lnu A, and lnu B. Multidrug resistance was identified in 27 Listeria strains, 4 belonging to L. monocytogenes. Resistance to clindamycin was the most common resistance phenotype and was identified in 45 Listeria strains; the mechanisms of resistance are still unknown. A medium prevalence of resistance to tetracycline (15 and 9 resistant and intermediate strains) and ciprofloxacin (13 resistant strains) was also found. Tet M was detected in Listeria strains with reduced susceptibility to tetracycline, providing evidence that both L. innocua and L. monocytogenes displayed acquired resistance. The presence of antimicrobial resistance genes in L. innocua and L. monocytogenes indicates that these genes may be transferred to commensal and pathogenic bacteria via the food chain; besides this, antibiotic resistance in L. monocytogenes could compromise the effective treatment of listeriosis in humans.

Emergence of Antibiotic Resistance in Listeria monocytogenes Isolated from Food Products: A Comprehensive Review

“…Zeinali, Jamshidi, Bassami, and Rad () indicated that 52.8%, 44.5%, 41.0%, 25.0%, and 16.7% of 36 L. monocytogenes isolates from fresh chicken carcasses were resistant to erythromycin, tetracycline, clindamycin, trimethoprim, and chloramphenicol. Escolar, Gómez, Del Carmen Rota García, Conchello, and Herrera () reported that 100% and 42.9% of seven L. monocytogenes isolates from RTE meat and dairy products were resistant to clindamycin and ciprofloxacin, respectively. In Egypt, Mohamed, Abdelmonem, and Amin () reported that all 47 L. monocytogenes isolates from frozen vegetables were resistant to amoxicillin, gentamicin, and norfloxacin.…”

“…Six classes of tetracycline resistance genes have been described in Gram‐positive bacteria ( tetK , tetL , tetM , tetO , tetP , and tetS ). However, only tetS , tetM , and tetL have been identified in L. monocytogenes (Charpentier & Courvalin, ; Escolar et al., ; Granier et al., ). It has also been reported that 19 of 38 L. monocytogenes isolates (50%) from dairy farms harbored more than one antibiotic resistance gene sequence.…”

Behavior of Listeria innocua Strains Under Pressure Treatment – Inactivation and Sublethal Injury

“…Listeria innocua was used in this study. This bacteria is physiologically very close to the previously mentioned L. monocytogenes, and is frequently found in the same food products, therefore it is often used for experiments [Escolar et al, 2017].…”

Molecular characterization of drug resistant Listeria monocytogenes from food and water samples

“…The tested organism, L. monocytogenes showed high resistance (100%) to rifampicin, trimethoprim / sulphamethoxazole, linezolid and oxacillin and low resistance (0%) to tetracycline and chloramphenicol (Figure 8). While studies showed that this bacterium has high resistance to rifampicin and oxacillin (Escolar et al, 2017;Kuan et al, 2017), results regarding chloramphenicol vary with other studies. Surprisingly, resistance to ciprofloxacin (87.5%), streptomycin (87.5%) and penicillin G (75%) was found to be high, whereas studies show sensitivity towards these antibiotics (Morvan et al, 2010;Kuan et al, 2017).…”

“…monocytogenes are capable of forming biofilms on many abiotic surfaces after short contact times of 20 min (Zadernowska et al, 2017). This formation of biofilms on surfaces like glass and stainless steel gives it the ability to be resistant to harsh chemicals such as detergents and antibiotics; this is because the microbes in the film are embedded in an Extracellular Polymeric Substance (EPS) (Escolar et al, 2017). Drug resistance also arises as a consequence of the misuse of antibiotics and incorrect dosage.…”