Distribution and characterization of dominant serovars of listeria monocytogenes strains isolated from woman with spontaneous abortion in tehran,iran

Maryam Rezaei,1,* Nadia kazemipour,2 Jalil vandyousefi ,3 Farokh rokhbakhsh zamin,4 Gholamreza irajian,5

1. Department of Microbiology Kerman branch Islamic Azad University Kerman, Iran
2. Department of Microbiology Kerman branch Islamic Azad University Kerman, Iran
3. Proffesor of Microbiology Shila Medical Diagnostic Laboratory Tehran, Iran
5. Department of Microbiology Iran University of Medical Science Tehran, Iran

Abstract

Introduction

Listeria monocytogenes a gram positive, non- sporulating , facultative, intracellular, a pathogenic bacterium that cause morbidity and mortality in human and livestock. it is a significant food-borne pathogen due its widespread distribution in nature, its ability to survive in a wide range of environmental condition, and its ability to grow at refrigeration temperature. listeria monocytogenes has been found in %10 normal health people usually in the gut. all the 13 serovars of listeria monocytogenes are reported to cause human listeriosis , but serovars 1/2a , 4b and 2c are in implicated with most cases. pregnant women are particularly prone to infection, the placental provides protective niche for the growth of listeria monocytogenes, thereby resulting in spontaneous abortion , stillbirth neonatal infection, severe necrotizing hepatitis, placental necrosis and increased risk of post implantation loss . latent listeriosis in pregnant women leads habitual abortion. in this study, all isolates from spontaneous abortions after confirmation with biochemical, api system were serotyped with a commercially available monoclonal antisera kit according to the manufacturer’s instruction. thepresent study described to detect dominant serovars (1/2a, 4b) in pathogenic listeria monocytogenes isolated from women with spontaneous abortion in tehran,iran

Methods

a total of 258 samples comprising placental bits (n=118), vaginal swabs (n=87) and blood (n=53), were collected from 123 patients with spontaneous abortion listeria monocytogenes isolated from 28 samples that confirmation of these isolates was based on biochemical tests, palcam agar with 5% sheep blood, camp test , pi-plc assay and api system, followed by invivo pathogenicity test and multiplex pcr to detect dominant serovars.

Results

In this study 28(18.8%) listeria monocytogenes with various serovars from 123 patients including 118(47.5%) placental bits, 54(20.5%) patients blood and 87(33.7%) vaginal swabs were isolated. the presence of listeria monocytogenes in placental bits and blood , in this study, indicated the most and the least outbreaks in all clinical sampling, it was completely confirmed with the studies of listeria monocytogenes isolates from vaginal secretion 35(14.5%) and in placental bits 53(7.5%) by pournajaf ,a, etal.(2016). [37] in this study from samples of placental bits , blood and vaginal secretion , belong to two patients in their second trimester of the pregnancy with averaged age of 28.5 listeria monocytogenes was isolation and all confirmation and pathogenicity tests invivo condition demonstrated the virulence of isolated species. listeria monocytogenes was isolated from placental bits belong to 37 years old patients with spontaneous abortion in the early trimester of pregnancy , with biochemical, serological and molecular confirmation experiments. listeria monocytogenes was also obtained from vaginal secretion as well as placental bits belong to three patients with the average age of 30 years old. meanwhile from 123 patients it only was isolated from placental bits. (17.7%) it is indicated that listeria monocytogenes has a desire to placental bits. therefore, in listeria monocytogenes from spontaneous or habitual abortions, in human or animal, the growing bacteria spot should be found in placental bits. in serological tests with monoclonal antibodies provided from (denka-japan company), in order to determine the dominant serovars of the isolated listeria monocytogenes in this research , according to the produces company,s instructions, from 28(18.8%) listeria monocytogenes cases obtained from 21(17.7%) placental bit , 2(3.77%) blood cases and 5(5.7%) vaginal secretions , serovars 1/2a and 4b were diagnosed dominant .it is for the first time in iran that serovars 1/2a and 4b are reported as dominant serovars which are isolated from spontaneous abortions , which fourteen 2a serovars 14(50%) are with the most of the cases in comparison, with 4b serovars 10(37.5%) .

Conclusion

The results indicated a presence of listeria monocytogenes in cases of spontaneous abortion was 46.6%. it seems 1/2a and 4b serovars have important role as essential dominant serotypes to cause spontaneous abortion. the results show the api system and multiplex pcr methods are sensitive and faster than culture and biochemical tests to detect listeria monocytogenes serovars from clinical samples.

Keywords

Dominant serovars, listeria monocytogenes, spontaneous abortion