Introduction: Leptospirosis is one of the neglected reemerging zoonoses that is of public health concern globally. The need to discover novel therapeutic alternatives for leptospirosis through screening for and elucidating the mechanism/s of the anti-leptospiral activity of plant extracts is therefore necessary. This study analyzes the optimized tube dilution technique and the BiologTM sole carbon utilization phenotype microarray as screening tool for anti-leptospiral activity of plant extracts. Methods: The suitability of the optimized tube dilution technique was evaluated by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and motility inhibition property of a plant extract and an antimicrobial control (pen G) against 4 dominantly circulating Leptospira serovars/serogroup in the Philippines. Likewise, the suitability of the BiologTM sole carbon utilization assay was evaluated using a plant extract and selected antimicrobials against L. interrogans serovar Manilae strain K64 and L. interrogans serovar Losbanos strain K37. Results: The MIC, MBC, and motility inhibition property of a plant extract and the antibiotic controls as well as its effect on the carbon utilization phenome of the Leptospira serovars gave consistent results, within and between several runs. With standard deviation = 0 for all serovars. The MIC and MBC of the antimicrobial control (pen G), the positive control, was 10 ug/ml. The growth control (leptospires without treatment), the negative control, showed presence of motile leptospires. The MIC and the MBC of the test plant extract was 250 ug/ml – 500 ug/ml. Results of the carbon utilization phenome or pattern of carbon utilization were consistent within the 3 replicates and between two runs. Conclusion The optimized tube dilution technique and the BiologTM sole carbon utilization assay is a potential in vitro screening tool for determining anti-leptospiral activity of plant extracts.
Leptospira ; Serogroup

BACKGROUND: Domestic animals are known to be either maintenance or accidental hosts of Leptospira. Determination of seroprevalence of leptospirosis among these animals is of great importance due to their close association with humans, economic loss as well as the public and veterinary health problems caused by the said zoonosis.

OBJECTIVE: This study aimed to determine the seroprevalence of leptospirosis among water buffaloes, pigs, and dogs in selected areas in the Philippines.

METHODS: Microscopic agglutination test (MAT) was used to test for leptospirosis. Testing was done from January 2007 to August 2008.

RESULTS: With the cut-off titer set at 1:80, the MAT-positivity rates were 82%, 67%, and 79% for 190 water buffaloes, 45 pigs, and 106 dogs, respectively. The most common prevailing serovars detected were Hardjo, Tarassovi, and Hebdomadis for water buffaloes; Semaranga, Grippotyphosa, and Patoc for pigs; and, Manilae, Patoc, and Autumnalis for dogs. MAT-positivity rates among these animals in terms of age (except for water buffaloes), sex and sample collection sites were not statistically significant. No Leptospira was isolated from the blood, urine, and kidney samples of these animals.

CONCLUSION: Results indicate a high seroprevalence of leptospirosis among the animals studied and that several pathogenic leptospires are causing infection in these animals.

Animal ; Seroepidemiologic Studies ; Leptospirosis ; Swine ; Philippines