Phylogenetics of Mycoplasma hominis clinical strains associated with gynecological infections or infertility as disclosed by an expanded multilocus sequence typing scheme

International audienceTo our knowledge, the phylodistribution of M. hominis clinical strains associated with various pathological conditions of the urogenital tract has not been explored hitherto. Here we analyzed the genetic diversity and phylogenetic relationships among 59 M. hominis Tunisian clinical isolates, categorized as gynecological infections-or infertility-associated pathotypes. For this purpose, we developed an expanded multilocus sequence typing (eMLST) scheme, combining the previously reported multilocus sequence typing (MLST) loci (gyrB, tuf, ftsY, uvrA, gap) with a new selected set of putative virulence genes (p120', vaa, lmp1, lmp3, p60), referred herein to as multi-virulence-locus sequence typing (MVLST) loci. In doing so, M. hominis population was segregated into two distinct genetic lineages, which were differentially associated with each pathotype. Such a clear dichotomy was supported by several phylogenetic and population genetic analysis tools. Recombination was found to take place, but not sufficient enough to break down the overall clonal population structure of M. hominis, most likely as a result of purifying selection, which accommodated the most fit clones. In sum, and owing to the eMLST scheme described herein, we provide insightful data on the phylogenetics of M. hominis, arguing for the existence of genetically differentiable urogenital pathotypes. Mycoplasma hominis, which belongs to the Mycoplasmataceae family, in the Mollicutes class, was the first myco-plasma species isolated from humans in 1937 1. It resides, as a commensal, in the lower urogenital tract of healthy persons. Under certain circumstances, M. hominis can cause a variety of genital infections such as bacterial vag-inosis, pelvic inflammatory disease, and cervicitis 2. This microorganism seems to be associated with pregnancy complications and neonatal diseases 3. In addition, several studies reported the pathogenic role of M. hominis in infertility 4,5. More interestingly, this species has been linked to a wide range of extragenital infections (septic arthritis, endocarditis, brain abscess), especially in immunocompromised patients 6-8. To better understand the epidemiology and the mode of spread of M. hominis, several molecular typing systems have been developed. These include Pulse-Field Gel Electrophoresis (PFGE), Restriction Fragment Length Polymorphism (RFLP) analysis, Amplified Fragment Length Polymorphism (AFLP), and Random Amplified Polymorphic DNA (RADP). All these methods have revealed a high degree of both genetic and antigenic het-erogeneity among M. hominis strains 9-12. Although informative, these approaches proved to be quite difficult t

Genetic variability of the P120' surface protein gene of Mycoplasma hominis isolates recovered from Tunisian patients with uro-genital and infertility disorders

<p>Abstract</p> <p>Background</p> <p>Among the surface antigens of <it>Mycoplasma hominis</it>, the P120' protein was previously shown to elicit a subtle antibody response and appears to be relatively conserved. To get better insight into the evolution of this protein, we analysed the genetic variability of its surface exposed region in 27 <it>M. hominis </it>isolates recovered from the genital tract of Tunisian patients with infertility disorders.</p> <p>Methods</p> <p>All specimens were processed for culture and PCR amplification of the N-terminal surface exposed region of p120' gene. PCR products were sequenced to evaluate the genetic variability, to test for adaptive selection, and to infer the phylogenetic relationship of the <it>M. hominis </it>isolates.</p> <p>Results</p> <p>Sequence analysis showed a total of 25 single nucleotide polymorphisms distributed through 23 polymorphic sites, yielding 13 haplotypes. All but one mutation were confined within three distinct regions. Analysis of the amino acid-based phylogenetic tree showed a predominant group of 17 closely related isolates while the remaining appear to have significantly diverged.</p> <p>Conclusion</p> <p>By analysing a larger sample of <it>M. hominis </it>recovered from patients with urogenital infections, we show here that the P120' protein undergoes substantial level of genetic variability at its surface exposed region.</p

Phylogenetics of Mycoplasma hominis clinical strains associated with gynecological infections or infertility as disclosed by an expanded multilocus sequence typing scheme

Abstract To our knowledge, the phylodistribution of M. hominis clinical strains associated with various pathological conditions of the urogenital tract has not been explored hitherto. Here we analyzed the genetic diversity and phylogenetic relationships among 59 M. hominis Tunisian clinical isolates, categorized as gynecological infections- or infertility-associated pathotypes. For this purpose, we developed an expanded multilocus sequence typing (eMLST) scheme, combining the previously reported multilocus sequence typing (MLST) loci (gyrB, tuf, ftsY, uvrA, gap) with a new selected set of putative virulence genes (p120’, vaa, lmp1, lmp3, p60), referred herein to as multi-virulence-locus sequence typing (MVLST) loci. In doing so, M. hominis population was segregated into two distinct genetic lineages, which were differentially associated with each pathotype. Such a clear dichotomy was supported by several phylogenetic and population genetic analysis tools. Recombination was found to take place, but not sufficient enough to break down the overall clonal population structure of M. hominis, most likely as a result of purifying selection, which accommodated the most fit clones. In sum, and owing to the eMLST scheme described herein, we provide insightful data on the phylogenetics of M. hominis, arguing for the existence of genetically differentiable urogenital pathotypes

Multiple alignment of the deduced amino acid sequences of the P120'surface exposed region of isolates (Mh1 to Mh27) relative to the reference strain PG21

<p><b>Copyright information:</b></p><p>Taken from "Genetic variability of the P120' surface protein gene of isolates recovered from Tunisian patients with uro-genital and infertility disorders"</p><p>http://www.biomedcentral.com/1471-2334/7/142</p><p>BMC Infectious Diseases 2007;7():142-142.</p><p>Published online 5 Dec 2007</p><p>PMCID:PMC2225410.</p><p></p> Dots indicate identical residues. The 3 regions where amino acid changes which tend to occur are underlined

Representative illustration of PCR amplification of the 510-bp fragment of

<p><b>Copyright information:</b></p><p>Taken from "Genetic variability of the P120' surface protein gene of isolates recovered from Tunisian patients with uro-genital and infertility disorders"</p><p>http://www.biomedcentral.com/1471-2334/7/142</p><p>BMC Infectious Diseases 2007;7():142-142.</p><p>Published online 5 Dec 2007</p><p>PMCID:PMC2225410.</p><p></p> M: 100 bp molecular size ladder, lanes 1 and 7: PG21 strain (positive control), lane 2: No DNA with Mhp120' primers (negative control), lanes 3–6: Mhp120' primers with DNA from ATCC 33530 (lane 3), ATCC 19989 (lane 4), ATCC 15531 (lane 5), and UuipT3 (lane 6), lanes 8–19: isolates