Antibiotic resistance in Listeria species isolated from catfish fillets and processing environment

Abstract

Aims: To investigate the susceptibility of 221 Listeria spp. (86 Listeria monocytogenes, 41 Listeria innocua and 94 Listeria seeligeri‐Listeria welshimeri‐Listeria ivanovii) isolated from catfish fillets and processing environment to 15 antibiotics. Methods and Results: Listeria isolates were analysed by disc‐diffusion assay for their resistance to 15 drugs. All isolates were resistant to cefotaxime and clindamycin but were sensitive to ampicillin, cephalothin, chloramphenicol, erythromycin, gentamycin, kanamycin, rifampin, streptomycin, sulfamethoxazole/trimethoprim and vancomycin. Unlike L. monocytogenes and L. seeligeri‐L. welshimeri‐L. ivanovii isolates, 22% of L. innocua isolates displayed tetracycline/oxytetracycline resistance. Screening of tet genes by PCR identified tet(M) gene in the chromosome of all tetracycline/oxytetracycline‐resistant L. innocua. However, this gene was not associated with the integrase gene of Tn1545. Repetitive extragenic palindromic‐ and enterobacterial repetitive intergenic consensus‐PCR typing methods showed no genotype‐specific tetracycline resistance in the tet(M)‐positive strains. Conclusions: Catfish fillets and processing environment were currently free of L. monocytogenes resistant to antibiotics commonly used in human listeriosis treatment. However, the presence of tet(M) gene in L. innocua raises the possibility of future acquisition of resistance by L. monocytogenes. Significance and Impact of the Study: These data will be helpful in improving background data on antibiotics resistance strains isolated from food and processing environment.

Characterization of antibiotic resistance in Listeria spp. isolated from slaughterhouse environments, pork and human infections

“…However, increasing reports of Listeria strains isolated from various sources that are resistant to penicillin, ampicillin, tetracycline, streptomycin, clindamycin, and even oxacillin and vancomycin represent a major public health concern [9][10][11]. The genetic mechanisms responsible for these resistances are an important research topic, given that L. monocytogenes can acquire resistance genes from, and transfer them to, enterococci, staphylococci, and streptococci [12,13].…”

Comparison of sample preparation for the isolation of Listeria species in naturally contaminated catfish and tilapia samples

“…in tilapia and its water was relatively higher than catfish and its water (Table 1). Other study found that Listeria was found in tilapia and catfish (Chen et al, 2010;Jaleewar et al, 2007). This study found 3 isolates of L. ivanovii isolated from catfish, 2 isolates of L. ivanovii, 2 isolates of L. grayi and 1 isolates of L. welshimeri isolated from tilapia.…”

“…However, catfish and tilapia are potential agents of pathogenic bacteria such as Listeria sp. (Chen et al, 2010;Jaleewar et al, 2007).…”

Isolation of Listeria monocytogenes in lamb meat and determination of the antibiotic resistance

“…Other studies also indicated that L. innocua is the most prevalent Listeria species found in food products (27,35,46). This may be related to differential selection during enrichment and recovery procedures, or because L. innocua is simply more common in the environment than L. monocytogenes (12,41). According to the studies L. innocua grows faster than the pathogenic species in enrichment broths therefore with the L. monocytogenes both species are present almost the same levels (35).…”