Influence of Selective Agents (EMJH-STAFF), Sample Filtration and pH on Leptospira interrogans Serovar Icterohaemorrhagiae Cultivation and Isolation from Swine Urine.

Romana Steinparzer,Friedrich Schmoll,Adi Steinrigl,Christine Unterweger,Tamara Mair

doi:10.3390/vetsci8060090

Romana Steinparzer, Friedrich Schmoll + Show 3 more

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https://doi.org/10.3390/vetsci8060090

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Abstract

Leptospira spp. cause the zoonotic disease leptospirosis, which occurs in numerous mammalians worldwide. Isolation is still important for serotyping and genotyping of Leptospira, which in turn is essential for epidemiological surveillance of leptospirosis and the development of diagnostic tests and vaccines. However, isolation of Leptospira from clinical specimens is inherently insensitive. This study was conducted to examine the influence of selective agents, sample filtration, sample pH and the use of phosphate buffered saline (PBS) buffer for sample storage to improve the success of cultivation and isolation of Leptospira interrogans serovar Icterohaemorrhagiae from swine urine. EMJH (Ellinghausen McCullough, Johnson and Harris) medium including the selective agents sulfamethoxazole, trimethoprim, amphotericin, fosfomycin and 5-fluorouracil (STAFF) increased the success of Leptospira isolation from spiked swine urine samples. Sample filtration yielded only negative results. Isolation in EMJH-STAFF was successful from swine urine with a density as low as 104 Leptospira/mL, and urine with pH ≤ 7 impaired the cultivation rate. Cultivation and isolation were not improved by the addition of PBS to spiked urine samples prior to storage for 24 h at 4 °C. The results of the study demonstrate that cultivation and isolation of leptospires from swine urine can be improved by enhanced methods.

Highlights

Leptospirosis is a worldwide occurring zoonotic disease caused by pathogenic Leptospira species
The aim of our study was to determine the influence of urine pH, selective agents (STAFF) and sample filtration on the success of Leptospira interrogans serovar Icterohaemorrhagiae cultivation and isolation from spiked swine urine
Most cultures with Leptospira plus contamination were detected after four weeks and with pure Leptospira after two weeks in both EMJH and EMJH + STAFF

Summary

Introduction

Leptospirosis is a worldwide occurring zoonotic disease caused by pathogenic Leptospira species. Numerous mammals are susceptible to the spirochetal disease including livestock and humans. Leptospirosis causes infertility, abortion and stillbirth [1]. Direct detection of Leptospira from samples can be performed by molecular diagnostic techniques and cultivation. Leptospira mainly affect the kidneys, the urogenital tract and the liver and they are shed in urine [2]. Tissue samples from affected organs and urine can be used for direct Leptospira detection. Molecular techniques are usually able to provide results within a short period of time, are (semi-)quantitative in the case of quantitative

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