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Rapid identification and characterization of Listeria monocytogenes are required for the food industry, epidemiological studies, and disease prevention and control. However, typing procedures are labor-intensive and time-consuming, and they require technical expertise, a panel of sera and reference culture strains or sophisticated and expensive equipment. To improve upon traditional diagnostic methods for L. monocytogenes we developed and evaluated an efficient procedure for the specific identification of L. monocytogenes and the major pathogenic serotypes of the species based on loop-mediated isothermal amplification (LAMP). Four individual reactions were designed using primers targeting any L. monocytogenes serotypes (LAMP-AS) and the 1/2a (LAMP-1/2a), 1/2b (LAMP-1/2b), and 4b (LAMP-4b) serotypes. The procedure distinguished L. monocytogenes from closely genetically related species and the targeted serotypes. Cross-reactivity with a few rare serotypes isolated from food or clinical samples did not impair the usefulness of the procedure. Thus, our approach constitutes a fast, easy and low-cost alternative for L. monocytogenes diagnosis and serotyping and may be useful for surveillance and epidemiological investigation programs.

Plague caused by Yersinia pestis is one of the infectious diseases subject to the International Health Regulations (IHR). Permanent monitoring of the focal plague areas is mandatory in order to enable prompt control measures to prevent the spread of the disease. Therefore, the availability of efficient diagnosis tests is of paramount importance. Here, we describe a loop-mediated isothermal amplification (LAMP)-based procedure for rapid Y. pestis detection. We constructed a set of LAMP primers, which were used in assays to establish the reaction conditions that would lead to the quick visualization of the results by evaluating the test tube with the naked eye. The primers were specifically designed to target the caf1 gene located on pFra/Tox (pMT), a prototypical plasmid of Y. pestis. The LAMP procedure was performed at 65°C for 45 min in a water bath and allowed for the detection of at least 10 pg of bacterial DNA. Due to its simplicity, specificity, sensitivity and rapidity, the LAMP technique is an additional tool that may be implemented in routine plague diagnoses, especially in emergencies.