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Listeria monocytogenes in spontaneous abortions in humans and its detection by multiplex PCR
S Kaur1, S V S Malik, V M Vaidya
1Division of Veterinary Public Health, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.
Aim:
To assess the extent of Listeria monocytogenes in causation of human spontaneous abortions by isolation methods and PCR analysis for the presence of virulence-associated genes.
Methods And Results:
A total of 305 samples comprising blood, urine, placental bits, faecal and vaginal swabs were collected from 61 patients with spontaneous abortions. Listeria spp. were isolated from 10 samples collected from nine (14.8%) patients. Confirmation of these isolates was based on biochemical tests, haemolysis on blood agar, CAMP test, phosphatidylinositol-specific phospholipase C (PI-PLC) assay followed by in vivo pathogenicity tests and multiplex PCR to detect virulence-associated genes (prfA, plcA, hlyA, actA and iap). Three isolates were confirmed as L. monocytogenes. Of these, two isolates turned out to be pathogenic and found to posses all five genes. However, the remaining two haemolytic L. monocytogenes isolates lacking the plcA gene and activity in the PI-PLC assay were found to be nonpathogenic by in vivo tests.
Conclusions:
The occurrence of pathogenic L. monocytogenes in cases of spontaneous abortions was 3.3%. It seems that the plcA gene and its expression have an important role as essential virulence determinants in pathogenic Listeria spp.
Significance And Impact Of The Study:
The recovery of pathogenic L. monocytogenes isolates from cases of spontaneous abortion indicates the significance of listeric infection in pregnant women.
Insights
Pathogenic Listeria monocytogenes, a cause of spontaneous abortion, was identified in 3.3% of cases. The plcA gene is crucial for Listeria virulence, highlighting the significance of listeric infections in pregnant women.
Area of Science:
- Microbiology
- Infectious Diseases
- Obstetrics and Gynecology
Background:
- Listeria monocytogenes is a foodborne pathogen.
- Listeriosis can cause severe outcomes in pregnant women, including spontaneous abortion.
- Virulence factors of Listeria monocytogenes are critical for pathogenesis.
Purpose of the Study:
- To determine the prevalence of Listeria monocytogenes in human spontaneous abortions.
- To identify virulence-associated genes in isolated Listeria strains.
- To assess the role of specific genes in Listeria pathogenesis.
Main Methods:
- Samples (blood, urine, placenta, etc.) collected from 61 patients with spontaneous abortions.
- Isolation and biochemical confirmation of Listeria species.
- Multiplex PCR to detect virulence genes (prfA, plcA, hlyA, actA, iap) and in vivo pathogenicity tests.
Main Results:
- Listeria spp. isolated from 9 patients (14.8%); 3 confirmed as Listeria monocytogenes.
- Two pathogenic Listeria monocytogenes isolates possessed all five tested virulence genes.
- Two nonpathogenic isolates lacked the plcA gene and phosphatidylinositol-specific phospholipase C (PI-PLC) activity.
Conclusions:
- Pathogenic Listeria monocytogenes occurred in 3.3% of spontaneous abortion cases.
- The plcA gene and its expression are important virulence determinants in Listeria.
- Listeric infection is significant in pregnant women experiencing spontaneous abortions.
