Molecular Based Detection and Antibiotic Sensitivity Profiling of Listeria monocytogenes Isolated from Different Meat Sources

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Fawad Shabir Memon et al.


Objective: Food borne infections are the major and growing public health concern. Listeria monocytogenes is one of the emerging pathogens responsible for major food borne outbreaks round the globe. In the following study, the prevalence and antimicrobial susceptibility pattern of L. monocytogenes in fresh and frozen meat samples was detected.  

Method: A total of 120 meat samples (60 fresh and 60 frozen) were collected from various sources including 10 samples each from chicken meat, chicken boneless meat, mutton, minced mutton, beef and minced beef. Identification of Listeria species was done using selective and differential medium (PALCAM agar and blood agar). The confirmation of L. monocytogenes was done by Polymerase chain reaction (PCR) using species specific primers for the amplification of hly A and iap genes. The confirmed isolates were subjected to antimicrobial susceptibility profiling.

Results: Of 120 meat samples 19 (15.83%) were found positive for L. monocytogenes. L. monocytogenes was more prevalent in frozen samples18.33% (11/60) in comparison to fresh meat samples 13.33% (08/60). Highest resistance was observed against Penicillin (63.15%) followed by Clindamycin (57.89%), Ciprofloxacin (36.84%) and Rifampicin (26.31%). All the 19 (100%) isolates were found susceptible to Cephalothin, chloramphenicol and vancomycin. Nine of the 19 isolates were found resistant to more than three classes of antibiotics hence, were declared as multidrug resistant (MDR). The most common pattern found was PEN-CLN-CIP among MDR phenotypes.

Conclusion:  L. monocytogenes could be a source of food born disease outbreak due to its simultaneous presence in fresh and frozen meat with a special focus to MDR strains. PCR based detection is a good tool for its detection in meat samples but there is a need to develop rapid and isothermal methods which may be directly applied on food samples for quick detection of food pathogens.

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