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Species identification and subtyping of Ureaplasma parvum and Ureaplasma urealyticum using PCR-based assays
1Centre for Infectious Diseases and Microbiology, Institute of Clinical Pathology and Medical Research, Westmead, New South Wales, Australia.
Abstract:
There is good evidence that the organism currently known as Ureaplasma urealyticum should be divided into two species-U. parvum (previously U. urealyticum biovar 1) and U. urealyticum (previously U. urealyticum biovar 2). In this study, we designed a series of primers, targeting the 16S rRNA gene and 16S rRNA-23S rRNA intergenic spacer regions, the urease gene subunits, and the 5' ends of the multiple-banded antigen (MBA) genes, to identify and subtype these Ureaplasma species. All of the species-specific primer pairs could distinguish the two species, but only subtype-specific primer pairs targeting the MBA genes could distinguish subtypes within each species. U. parvum was separated into three subtypes, represented by serovars 1, 3/14, and 6. U. urealyticum was also separated into three subtypes by PCR and/or direct sequencing. Subtype 1 consisted of serovars 2, 5, 8, and 9; subtype 2 contained serovars 4, 10, 12, and 13; and subtype 3 contained serovars 7 and 11. A selection of primer pairs was used to identify and subtype 78 clinical ureaplasma isolates from vaginal swabs of pregnant women and to identify and subtype ureaplasmas directly in 185 vaginal swabs in which they had been previously detected. U. parvum was identified in 228 (87%) of 263 isolates or specimens, and U. urealyticum was identified in 50 (19%) (both were present in 6%). Serovars 3/14 (48%) and 1 (43%) were most common among U. parvum isolates, and subtypes 2 (62%) and 1 (34%) were most common among U. urealyticum isolates. This new PCR-based typing system will facilitate future studies of the relationship between individual Ureaplasma species or subtypes and human disease.
Insights
This study introduces a new PCR method to differentiate Ureaplasma parvum and Ureaplasma urealyticum, along with their subtypes. This advancement aids in understanding the link between Ureaplasma types and human health conditions.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- The organism Ureaplasma urealyticum is now recognized as two distinct species: Ureaplasma parvum (formerly biovar 1) and Ureaplasma urealyticum (formerly biovar 2).
- Accurate identification and subtyping of these species are crucial for understanding their roles in human health and disease.
Purpose of the Study:
- To develop and validate a polymerase chain reaction (PCR)-based method for differentiating Ureaplasma parvum and Ureaplasma urealyticum.
- To identify and subtype these Ureaplasma species using novel primer sets targeting specific genes.
Main Methods:
- Design and application of species-specific and subtype-specific primer pairs targeting the 16S rRNA gene, 16S rRNA-23S rRNA intergenic spacer regions, urease gene subunits, and multiple-banded antigen (MBA) genes.
- PCR and direct sequencing were employed for identification and subtyping.
- The developed method was applied to clinical isolates and vaginal swab specimens from pregnant women.
Main Results:
- All designed species-specific primer pairs successfully distinguished between U. parvum and U. urealyticum.
- Subtype-specific primers targeting MBA genes differentiated subtypes within each species: U. parvum into three subtypes (serovars 1, 3/14, 6) and U. urealyticum into three subtypes (serovars 2, 5, 8, 9; 4, 10, 12, 13; and 7, 11).
- U. parvum was detected in 87% and U. urealyticum in 19% of 263 specimens, with serovar 3/14 (48%) and subtype 2 (62%) being the most prevalent within their respective species.
Conclusions:
- A novel PCR-based typing system effectively identifies and differentiates Ureaplasma parvum and Ureaplasma urealyticum species and their subtypes.
- This system provides a valuable tool for future research into the association between specific Ureaplasma species/subtypes and human diseases.