agar and Leptospirosis

Topics: Agar; Animals; Blood; Cerebrospinal Fluid; Cricetinae; Culture Media; Fluorescent Antibody Technique; Fluorouracil; Guinea Pigs; Kidney; Leptospira; Leptospirosis; Mice; Microscopy; Plasma; Rabbits; Rats; Serum Albumin, Bovine; Staining and Labeling; Urine; Water Microbiology

A toolbox for chemotaxis assay adapted to Leptospira spp. has emerged in the recent years: soft agar assay, capillary assay, and videomicroscopy tracking. Those methods allow to demonstrate chemotaxis defect, identify diverse chemoattractants, or decipher motile behavior quantitatively. These experiments have demonstrated a role of motility and potentially chemotaxis in leptospirosis pathogenesis. We describe extensively the methods and provide the key steps to use this toolbox.

Topics: Agar; Biological Assay; Chemotactic Factors; Chemotaxis; Electrophoresis, Capillary; Leptospira; Leptospirosis

Leptospirosis is a global zoonotic disease caused by pathogenic bacteria of the

Topics: Agar; Anti-Bacterial Agents; Azithromycin; Ciprofloxacin; Culture Media; Disk Diffusion Antimicrobial Tests; Drug Resistance, Multiple, Bacterial; Humans; Laos; Leptospira; Leptospirosis

Pathogenic Leptospira spp., the causative agents of leptospirosis, are slow-growing Gram-negative spirochetes. Isolation of Leptospira from clinical samples and testing of antimicrobial susceptibility are difficult and time-consuming. Here, we describe the development of a new solid medium that facilitates more-rapid growth of Leptospira spp. and the use of this medium to evaluate the Etest's performance in determining antimicrobial MICs to drugs in common use for leptospirosis. The medium was developed by evaluating the effects of numerous factors on the growth rate of Leptospira interrogans strain NR-20157. These included the type of base agar, the concentration of rabbit serum (RS), and the concentration and duration of CO(2) incubation during the initial period of culture. The highest growth rate of NR-20157 was achieved using a Noble agar base supplemented with 10% RS (named LVW agar), with an initial incubation at 30°C in 5% CO(2) for 2 days prior to continuous culture in air at 30°C. These conditions were used to develop the Etest for three species, L. interrogans (NR-20161), L. kirschnerii (NR-20327), and L. borgpetersenii (NR-20151). The MICs were read on day 7 for all samples. The Etest was then performed on 109 isolates of pathogenic Leptospira spp. The MIC(90) values for penicillin G, doxycycline, cefotaxime, ceftriaxone, and chloramphenicol were 0.64 units/ml and 0.19, 0.047, 0.5, and 2 μg/ml, respectively. The use of LVW agar, which enables rapid growth, isolation of single colonies, and simple antimicrobial susceptibility testing for Leptospira spp., provides an opportunity for new areas of fundamental and applied research.

Topics: Agar; Animals; Anti-Bacterial Agents; Carbon Dioxide; Colony Count, Microbial; Culture Media; Humans; Leptospira interrogans; Leptospirosis; Microbial Sensitivity Tests; Rabbits

Topics: Agar; Animals; Cattle; Cattle Diseases; Leptospirosis; Rodent Diseases