Abstract
AimThis study was designed to investigate the occurrence of serotypes of Listeria monocytogenes, an important food-borne pathogen, in gallbladder samples from cattle and sheep.Materials and MethodsThree hundred samples were collected and screened for the presence of L. monocytogenes. The identification of the isolates was confirmed by API-Listeria system and by the presence of hemolysin (hyl) gene. The isolates were subjected to polymerase chain reaction-based serotype identification with d1 (division 1), d2 (division 2), glt, mama (mismatch amplification mutation assay), and flaA (flagellin protein) genes.ResultsA total of 8 (2.7%) L. monocytogenes were recovered from 6 (4.0%) samples of sheep and 2 (1.3%) samples of cattle. All isolates showed positive results with Hly primers. Four isolates carried d1 gene, did not possess glt gene and harbored mama gene. The serotypes of these isolates were identified as 4a or 4c. The other 4 isolates carried d2 gene, 3 of them were positive with the FlaA primers, and hence, determined to be a 1/2a or 3a serotype, and 1 isolate was determined to be 1/2c or 3c serotype.ConclusionThis study concluded that the presence of 1/2a serotype in gallbladder samples indicates public health risk through cross-contamination of meat at slaughterhouses.
Highlights
Listeria monocytogenes is a Gram-positive, facultative, intracellular bacterial pathogen that causes morbidity and mortality in human and livestock [1]
This study concluded that the presence of 1/2a serotype in gallbladder samples indicates public health risk through cross-contamination of meat at slaughterhouses
The identification of the suspect colonies was confirmed as they appeared as typical Listeria species when they subcultured onto HiChrom Listeria agar plates and incubated at 37°C for 48 h
Summary
Listeria monocytogenes is a Gram-positive, facultative, intracellular bacterial pathogen that causes morbidity and mortality in human and livestock [1]. It is a significant foodborne pathogen due to its widespread distribution in nature [2]. Gahan and Hill [3] have already described the isolation of L. monocytogenes from the gallbladder in humans. L. monocytogenes strains are serotyped according to variation in the somatic (O) and flagellar (H) antigens [5]. More than 13 serotypes of L. monocytogenes have been described [6], only three
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