Detection of Leptospira in environmental samples of wet markets and paddy fields in Penang, Malaysia.

Abstract

Leptospirosis, caused by the Leptospira spp., is endemic in humid subtropical and tropical climates. Several environmental settings can harbour the survival of Leptospira; hence, continuous surveillance of the high-risk areas is critical. This study was conducted to detect the presence of Leptospira in wet markets and paddy fields in Penang, Malaysia. A total of 62 soil and water samples were collected aseptically from three wet markets and two paddy fields. The samples were cultured twice on the sampling day and after two weeks of storage in the dark at ambient temperature. All environmental samples and positive cultures were subjected to deoxyribonucleic acid (DNA) extraction and polymerase chain reaction (PCR) targeting 16S rRNA, lipL32 and rrs genes. 16S rRNA-positive samples were further sent for sequencing. Of 62 samples, 21 (21/62, 33.9%) tested positive via culture and PCR. Wet markets significantly had a higher detection rate of leptospires (29%) than paddy fields (4.8%). Four Leptospira species (L. selangorensis, L. dzoumogneensis, L. mtsangambouensis, and L. meyeri) were identified in wet markets and three (L. meyeri, L. wolffii, and L. kmetyi) in paddy fields. Storing the environmental samples for two weeks before isolation yielded a higher positivity (11/14) than culturing samples on the sampling day (6/14). The presence of Leptospira in the environment of wet markets and paddy fields in Penang although primarily intermediate and saprophyte indicates the crucial need to implement preventive measures to prevent the possibility of leptospirosis infection among the workers.