A retrospective study on nested PCR detection of syphilis treponemes in clinical samples: PCR detection contributes to the diagnosis of syphilis in patients with seronegative and serodiscrepant results.

Syphilis, caused by Treponema pallidum ssp. pallidum (TPA), is a persisting global health problem. Although syphilis diagnostics relies mainly on serology, serological tests have some limitations, and it is recommended that the final diagnosis be supported by additional tests. The purpose of this study was to analyze the relationship between serology and PCR in syphilis diagnostics. From the year 2004 to May 2019, a total of 941 samples were taken from 833 patients suspected of having syphilis, in Czech Republic. In all these samples, both nested PCR detection of TPA and serology testing were performed. Of the 941 samples, 126 were seronegative, 651 were seropositive, and 164 were serodiscrepant. Among seronegative samples (n = 126), 11 were PCR-positive (8.7%). Among seropositive samples (n = 651; i.e., samples positive for both non-treponemal and treponemal serology tests), 368 samples were PCR-positive (56.5%). The remaining 164 serodiscrepant samples included RPR negative and treponemal serological test-positive samples (n = 154) and a set of 10 RPR-positive samples negative in treponemal serological tests. While the first group revealed 73 PCR-positive samples (47.4%), the second revealed 5 PCR positive samples (50.0%). PCR detection rates were highest in primary syphilis, with lower rates in the secondary and undetermined syphilis stages. As shown here, the nested PCR can improve diagnostics of syphilis, especially in seronegative patients and in patients with discrepant serology.

MLST typing of Treponema pallidum subsp. pallidum in the Czech Republic during 2004-2017: Clinical isolates belonged to 25 allelic profiles and harbored 8 novel allelic variants.

A recently introduced Multilocus Sequence Typing scheme for Treponema pallidum subsp. pallidum was applied to clinical samples collected from 2004 to 2017 from the two largest cities (Prague and Brno) in the Czech Republic. Altogether, a total of 675 samples were tested in this study and 281 of them were found PCR-positive for treponemal DNA and typeable. Most of the typed samples (n = 281) were swabs from primary or secondary syphilis lesions (n = 231), and only a minority were whole blood or tissue samples (n = 50). Swab samples from patients with rapid plasma regain (RPR) values of 1-1024 were more frequently PCR-positive (84.6%) compared to samples from patients with non-reactive RPR test (46.5%; p-value = 0.0001). Out of 281 typeable samples, 136 were fully-typed at all TP0136, TP0548, and TP0705 loci. Among the fully and partially typed samples, 25 different allelic profiles were identified. Altogether, eight novel allelic variants were found among fully (n = 5) and partially (n = 3) typed samples. The distribution of TPA allelic profiles identified in the Czech Republic from 2004 to 2017 revealed a dynamic character with allelic profiles disappearing and emerging over time. While the number of samples with the A2058G mutation was seen to increase (86.7% in 2016/2017), the number of samples harboring the A2059G mutation was found to have decreased over time (3.3% in 2016/2017). In addition, we found several allelic profile associations with macrolide resistance or susceptibility, the gender of patients, as well as patient residence.

Molecular typing of Treponema pallidum in the Czech Republic during 2011 to 2013: increased prevalence of identified genotypes and of isolates with macrolide resistance.

From January 2011 to December 2013, a total of 262 samples, from 188 patients suspected of having syphilis were tested for the presence of treponemal DNA by PCR amplification of five chromosomal loci, including the polA (TP0105), tmpC (TP0319), TP0136, TP0548, and 23S rRNA genes. Altogether, 146 samples from 103 patients were PCR positive for treponemal DNA. A set of 81 samples from 62 PCR-positive patients were typeable, and among them, nine different genotypes were identified. Compared to a previous study in the Czech Republic during 2004 to 2010, the number of genotypes detected among syphilis patients in a particular year increased to six in both 2012 and 2013, although they were not the same six. The proportion of macrolide-resistant clinical isolates in this 3-year study was 66.7%.

Syphilis-causing strains belong to separate SS14-like or Nichols-like groups as defined by multilocus analysis of 19 Treponema pallidum strains.

Treponema pallidum strains are closely related at the genome level but cause distinct diseases. Subspecies pallidum (TPA) is the causative agent of syphilis, subspecies pertenue (TPE) causes yaws while subspecies endemicum (TEN) causes bejel (endemic syphilis). Compared to the majority of treponemal genomic regions, several chromosomal loci were found to be more diverse. To assess genetic variability in diverse genomic positions, we have selected (based on published genomic data) and sequenced five variable loci, TP0304, TP0346, TP0488, TP0515 and TP0558, in 19 reference Treponema pallidum strains including all T. pallidum subspecies (TPA, TPE and TEN). Results of this multilocus analysis divided syphilitic isolates into two groups: SS14-like and Nichols-like. The SS14-like group is comprised of SS14, Grady, Mexico A and Philadelphia 1 strains. The Nichols-like group consisted of strains Nichols, Bal 73-1, DAL-1, MN-3, Philadelphia 2, Haiti B and Madras. The TP0558 locus was selected for further studies because it clearly distinguished between the SS14- and Nichols-like groups and because the phylogenetic tree derived from the TP0558 locus showed the same clustering pattern as the tree constructed from whole genome sequences. In addition, TP0558 was shown as the only tested locus that evolved under negative selection within TPA strains. Sequencing of a short fragment (573bp) of the TP0558 locus in a set of 25 clinical isolates from 22 patients collected in the Czech Republic during 2012-2013 revealed that clinical isolates follow the SS14- and Nichols-like distribution.

Incidence, Clinical Features, Risk Factors and Outcome of Bacteremia due to Vancomycin-Resistant and Vancomycin-Sensitive Enterococcus Species Analyzed Over a 7-year Period in a Single Cancer Institution.

The aim of this study was to retrospectively compare the incidence, risk factors, and outcome in patients seen over a 7-year period at the National Cancer Institute in the Slovak Republic, with vancomycin-sensitive or vancomycin-resistant enterococcal bacteremia. The total incidence of enterococcal bacteremia at the National Cancer Institute increased from 5.1% in 1991 to 11.1% in 1993 and then decreased to 4.3% in 1995. Analysis of the 77 episodes of enterococcal bacteremia from 66 patients showed that 69 episodes from 60 patients were due to vancomycin-sensitive Enterococcus faecalis (group 1) and 8 episodes from 8 patients were due to vancomycin-resistant Enterococcus faecium (group 2). The features most frequently associated with enterococcal bacteremia were the insertion of a central venous catheter, neutropenia lasting more than 10 days, previous therapy with cephalosporins or vancomycin, previous prophylaxis with quinolones, and the incidence of superinfections. There was no difference in the clinical course or outcome between the 2 study groups. Previous therapy with aminoglycosides, cephalosporins, vancomycin or imipenem, neutropenia less than 10 days in length, malignancies other than leukemia or solid tumors, and the incidence of breakthrough bacteremia significantly correlated with patients with vancomycin-resistant E. faecium rather than patients with vancomycin-sensitive E. faecalis. The overall mortality was similar in both groups and averaged 32.5% for all enterococcal bacteremic patients. In this study, the major risk factors associated with cancer patients for developing vancomycin-resistant enterococcal bacteremia were previous therapy with aminoglycosides, cephalosporins or vancomycin, superinfections with other organisms and the incidence of breakthrough bacteremia.