Occurrence and phenotypic and molecular characterization of Listeria monocytogenes and Salmonella spp. in slaughterhouses in southern Brazil

Listeria monocytogenes and Salmonella spp. are considered important foodborne pathogens that are commonly associated with foods of animal origin. The aim of this study was to perform molecular characterization of L. monocytogenes and Salmonella spp. isolated from biofilms of cattle and poultry slaughterhouses located in the Federal District and State of Goiás, Brazil. Fourteen L. monocytogenes isolates and one Salmonella sp. were detected in poultry slaughterhouses. No isolates were detected in cattle slaughterhouses. All L. monocytogenes isolates belonged to lineage II, and 11 different pulsotypes were detected. Pulsed-field gel electrophoresis analysis revealed the dissemination of two strains within one plant, in addition to the regional dissemination of one of them. The Salmonella isolate was identified via whole genome sequencing as Salmonella enterica serovar Minnesota ST548. In the sequence analysis, no premature stop codons were detected in the inlA gene of Listeria. All isolates demonstrated the ability to adhere to Caco-2 cells, while 50% were capable of invading them. Antimicrobial resistance was detected in 57.1% of the L. monocytogenes isolates, and resistance to sulfonamide was the most common feature. The tetC, ermB, and tetM genes were detected, and four isolates were classified as multidrug-resistant. Salmonella sp. was resistant to nine antimicrobials and was classified as multidrug-resistant. Resistance genes qnrB19, blaCMY-2, aac(6’)-Iaa, sul2, and tetA, and a mutation in the parC gene were detected. The majority (78.5%) of the L. monocytogenes isolates were capable of forming biofilms after incubation at 37°C for 24 h, and 64.3% were capable of forming biofilms after incubation at 12°C for 168 h. There was no statistical difference in the biofilm-forming capacity under the different evaluated conditions. Salmonella sp. was capable of forming biofilms at both tested temperatures. Biofilm characterization was confirmed by collecting the samples consistently, at the same sampling points, and by assessing biofilm formation in vitro. These results highlight the potential risk of cross-contamination in poultry slaughterhouses and the importance of surveillance and pathogen control maintenance programs within the meat production industry.

Download Full-text

Molecular characterization of Listeria monocytogenes isolates from a small-scale meat processor in Montenegro, 2011–2014

Food Microbiology ◽

10.1016/j.fm.2018.12.005 ◽

2019 ◽

Vol 79 ◽

pp. 116-122 ◽

Cited By ~ 7

Author(s):

Ivana Zuber ◽

Brankica Lakicevic ◽

Ariane Pietzka ◽

Dubravka Milanov ◽

Vesna Djordjevic ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Molecular Characterization ◽

Small Scale

Download Full-text

Prevalence and Molecular Characterization of Microbial Contaminants in Raw Cow Milk of Tangail District in Bangladesh

Current Nutrition & Food Science ◽

10.2174/1573401317666210830114109 ◽

2021 ◽

Vol 17 ◽

Author(s):

Shahin Mahmud ◽

Md. Firoz Ali ◽

Md. Omar Faruque ◽

Muhammad Wasim ◽

Fatematuz Zuhura Evamoni ◽

...

Keyword(s):

Molecular Characterization ◽

Raw Milk ◽

Health Impact ◽

Cow Milk ◽

Milk Consumption ◽

Salmonella Spp ◽

Mean Values ◽

The Mean ◽

Quality Of Milk

Objectives: The aim of this study is to evaluate the microbial quality and associated health Methodology: An intensive study was carried out from January¬ to October 2019 at the Tangail district of Bangladesh to assess bacterial contamination of raw milk. A total of 60 samples were examined by following the standard bacteriological methods and the health impact was evaluated with the help of a semi-structured-based questionnaire. Molecular characterization of isolated bacteria was carried out by PCR. Results: Results revealed the mean values of TVC and TCC in raw milk, udder, oil, and utensil samples were 7.6×106, 8.8×106, 4.6×106, and 1.3×106 cfu/ml and 3.7×105, 1.4×106, 4.4×105, and 8.9×104 cfu/ml, respectively. The yeast and mold in raw milk, udder, and oil were 1.5×103, 1.8×103, and 1.3×102cfu/ml, respectively, and the mean values of E. coli in the above-mentioned samples were 1.9×103, 1.8×104, 2.1×103, and 1.6×103cfu/ml, respectively. On the other hand, the mean values of Salmonella spp. in raw milk, udder, oil, and utensil samples were 2.4×102, 7.9×102, 1.5×102, and 1.1×102cfu/ml, respectively. Some selected isolates confirmed by molecular identification were tested for their sensitivity against some common antibiotics used in Bangladesh. Escherichia coli showed 70% resistance to Amoxicillin and 90% sensitivity to Ciprofloxacin whereas Salmonella spp. And Staphylococcus aureus showed 90% resistance to Ampicillin and both were 80% and 90% sensitive to Ciprofloxacin, respectively. Conclusion, Significance, and Impact of Study: Milk producers should be appropriately trained to monitor the overall hygienic conditions surrounding the production and handling of milk until it reaches the consumer. Frequent monitoring of the milk production facility, occasional testing of raw milk, and minimal use of antibiotics will ensure the quality of milk. Consumption of quality milk and avoidance of raw milk consumption will reduce the health risk of the consumers.

Download Full-text