Etiological analysis of a patient with Listeria monocytogenes infection

ObjectiveTo investigate the etiology and traceability of an infection case caused by Listeria monocytogenes.

MethodsOn the basis of Field epidemiological investigation, samples of patient, foods, kitchen environmental appliances were collected for strain isolation and identification. Six pairs of virulence genes (prfA, plcB, hly, actA, iap, inlA) of positive strains were tested. The positive strains were analyzed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) techniques. The homologous analysis was finally performed on the isolated strain.

ResultsSix strains of Listeria monocytogenes were isolated, one from the case, two from the kitchen environmental kit, and three from the food of patient's family. In addition to the deletion of the virulence gene of the strain plcB detected by the two samples of the refrigerator inner wall and canned sweet corn, the other five virulence and all the virulence genes of other strains were all positive.. The isolated strains were all ST121 type, and the PFGE band type was 100% consistent.

ConclusionThe reason for the prevalence of this patient was due to poor hygiene in the home kitchen and contamination of both food and the environment.