Antimicrobial resistance and co-selection phenomenon in Listeria spp. recovered from food and food production environments

• Published in: Food microbiology 2013-06, Vol.34 (2), p.319-327
• Main Authors: Kovacevic, Jovana, Sagert, Jason, Wozniak, Anna, Gilmour, Matthew W., Allen, Kevin J.
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Antimicrobial resistance; Biological and medical sciences; Cattle; Co-selection; Cross-resistance; Dairy Products - microbiology; Drug Resistance, Multiple, Bacterial; Efflux pump; Fishes; Food Contamination - analysis; Food Handling; Food industries; Food microbiology; Fundamental and applied biological sciences. Psychology; Listeria - classification; Listeria - drug effects; Listeria - genetics; Listeria - isolation & purification; Listeria monocytogenes; Listeria spp; Seafood - microbiology
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2013.01.002

Antimicrobial resistance (AMR), co-selection phenomenon, and the relationship between reduced susceptibility (RSC) to ciprofloxacin (CIP) and resistance to other antimicrobials in Listeria spp. (n = 103) recovered from food processing environments (FPE) and food were investigated. Resistance of Listeria monocytogenes and other listeriae, respectively, to cefoxitin (FOX; 98% vs. 88%), CIP (7% vs. 4%), clindamycin (CLI; 33% vs. 59%) and tetracycline (6% vs. 8%) was observed, as was RSC to CIP (67% vs. 57%) and CLI (65% vs. 41%). L. monocytogenes also possessed RSC to linezolid (LZD; 6%), rifampicin (2%) and streptomycin (6%), with other listeriae displaying RSC to chloramphenicol (4%). L. monocytogenes serotype 1/2a (90%) isolates were more frequently resistant or possessed RSC to CIP compared to serotype 4b (55%) (p = 0.015). When eight strains were experimentally adapted to high concentrations of CIP, co-selection occurred as MICs to benzalkonium chloride (BAC) increased (n = 5), gentamicin MICs remained the same (n = 6) or increased 2-fold (n = 2), and led to RSC to LZD (n = 1) and resistance to CLI (n = 8). Overall, levels of resistance/RSC to CIP in food chain isolates, particularly 1/2a, are concerning. Further, reduced sensitivity to disparate antimicrobials following CIP exposure highlights the need for increased knowledge of co-selection phenomenon linked with antimicrobial agents. ► AMR was observed in all Listeria, and included clinically relevant antimicrobials. ► Most Listeria spp. were resistant or had reduced susceptibility to ciprofloxacin. ► Serotype 1/2a strains were more frequently tolerant to ciprofloxacin than 4b. ► Ciprofloxacin (CIP) adaptation led to AMR co-selection phenomenon. ► Experimental CIP adaptation led to increased tolerance to BAC, CLI and GEN.