Characteristics of polymerase chain reaction-positive syphilis cases in Manitoba, Canada, 2017 to 2020: Demographic analysis, specimen types, and Treponema pallidum gene targets.

BACKGROUND: A resurgence of syphilis infections has been described in a number of countries including Canada in the last decade. METHODS: This study identified polymerase chain reaction (PCR) positive syphilis cases based on detection of Treponema pallidum genes (polA, tpp47, and bmp) in 3,350 clinical specimens obtained from patients in the province of Manitoba, Canada between 2017 and 2020. Patient demographics were obtained from specimen requisition forms. RESULTS: PCR identified 740 syphilis cases: 718 were adolescents and adults, while 22 were congenital syphilis cases. For non-congenital syphilis investigation, the clinical specimens with the highest yield of positive PCR results were genital (632), oral (73), and anal (55), while for congenital syphilis, they were nasal or nasopharyngeal secretions (20), followed by blood (5) and umbilical cord (4). Female syphilis cases appeared younger (61.7% between 14 and 29 years), while male syphilis cases appeared older (58.4% between 30 and 65 years). Although, overall more syphilis cases (62.7%) occurred in the urban cities; the proportion of urban cases showed a significant decline from 87.0% in 2017 to 55.6% in 2020, while in rural regions it increased from 13.0% in 2017 to 44.4% in 2020. Most (98.8%) PCR- positive specimens were found to contain all three T. pallidum genes and 99.8% also displayed the macrolide resistance genotype. CONCLUSIONS: This study identified the clinical specimen types and T. pallidum genes most suitable for PCR diagnosis of syphilis. Changing demographics of cases were noted over time.

HISTORIQUE: Depuis dix ans, les infections par la syphilis sont en recrudescence dans plusieurs pays, y compris le Canada. MÉTHODOLOGIE: La présente étude relève les cas positifs à l'amplification en chaîne par polymérase (PCR) d'après la détection des gènes du Treponema pallidum (polA, tpp47 et bmp) dans 3 350 échantillons cliniques prélevés auprès de patients de la province du Manitoba, au Canada, entre 2017 et 2020. Les caractéristiques démographiques des patients sont tirées des formulaires de réquisition des prélèvements. RÉSULTATS: Le test PCR a permis de détecter 740 cas de syphilis, soit 718 chez des adolescents et des adultes et 22 cas de syphilis congénitale. Pour ce qui est des examens de la syphilis non congénitale, les échantillons cliniques donnant le plus fort taux de résultats positifs au test PCR ont été prélevés dans la région génitale (632), orale (73) et anale (55), tandis qu'à l'égard des cas de syphilis congénitale, ils provenaient des sécrétions nasales ou nasopharyngées (20), suivis du sang (5) et du cordon ombilical (4). La syphilis se manifestait chez des femmes plus jeunes (61,7 % entre 14 et 29 ans) et plus tard chez les hommes (58,4 % entre 30 et 65 ans). Même si, dans l'ensemble, plus de cas de syphilis (62,7 %) se déclaraient en région urbaine, cette proportion a connu un recul important, passant de 87,0 % en 2017 à 55,6 % en 2020, tandis que la proportion des cas en région rurale a progressé de 13,0 % en 2017 à 44,4 % en 2020. La plupart des échantillons ayant obtenu un résultat positif au test PCR (98,8 %) contenaient les trois gènes du T. pallidum, et 99,8 % possédaient également le génotype de résistance aux macrolides. CONCLUSIONS: La présente étude a relevé les types d'échantillons cliniques et les gènes de T. pallidum les plus appropriés pour le diagnostic de syphilis par test PCR. On constate une évolution de la démographie des cas au fil du temps.

Laboratory evaluation of two point-of-care test kits for the identification of infectious syphilis.

Background: Syphilis is a sexually transmitted disease that can have atypical clinical presentations. Conventional laboratory tests to confirm the diagnosis are not rapid enough to affect clinical decision on treatment and contact tracing. Rapid point-of-care tests (POCT) can be useful for control of infectious diseases; however, no POCT for syphilis detection is currently available in Canada. The aim of this study is to evaluate two POCTs (RevealTM Rapid TP (Treponema pallidum) Antibody test and DPP® Syphilis Screen and Confirm test) for detection of infectious syphilis. Methods: One hundred serum samples with known syphilis serological status, based on treponemal and non-treponemal test results, were analysed in the laboratory with two POCTs by two independent operators in a blind fashion. Results were analysed to evaluate their ability to detect infectious syphilis. Results: The Reveal Rapid TP Antibody POCT showed an overall sensitivity of 95.0% and a specificity of 83.3%, while the DPP Syphilis Screen and Confirm POCT showed a sensitivity of 87.5% and a specificity of 98.3%. Both POCTs gave a sensitivity of 100% on active syphilis samples with Venereal Disease Research Laboratory (VDRL) titres of greater than 1:4, but their sensitivities decreased for samples with low VDRL titres. Both POCTs gave weakly or very weakly reactive results on 11.3%-25.0% of the treponemal antibody positive samples. Conclusion: This laboratory evaluation has shown promising results for both POCTs to detect infectious syphilis. Further evaluations in the field would be required to confirm this preliminary finding.

Whole genome sequencing to study the phylogenetic structure of serotype a Haemophilus influenzae recovered from patients in Canada.

This study examined the phylogenetic structure of serotype a Haemophilus influenzae (Hia) isolates recovered from patients in Canada. Hia isolates from 490 separate patients and an American Type Culture Collection (ATCC) strain were analyzed by multilocus sequence typing (MLST), with 18 different sequence types (STs) identified. Most (85.7%) Hia patient isolates were typed as ST-23 and another 12.7% belonged to 14 different STs with 6, 5, or 4 MLST gene loci related to ST-23 (ST-23 complex). Core genome single-nucleotide variation phylogeny (SNVPhyl) on whole genome sequence (WGS) data of 121 Hia patient isolates representing all identified STs and the ATCC strain revealed 2 phylogenetic populations, with all the ST-23 complex isolates within 1 population. The other phylogenetic population contained only the ATCC strain and 3 patient isolates. Concatenated hitABC sequences retrieved from WGS data and analyzed by MEGA (Molecular Evolutionary Genetic Analysis) alignment confirmed the phylogeny obtained by SNVPhyl. The sodC gene was found only in isolates in the minor phylogenetic population. The 2 phylogenetic populations of the Canadian Hia isolates are similar to the 2 clonal divisions described for serotype b H. influenzae. Combining MLST, core SNVPhyl, and hitABC gene sequence alignment showed that most (99.4%) Canadian Hia patient isolates belonged to 1 major phylogenetic population.

Molecular Typing and Macrolide Resistance of Syphilis Cases in Manitoba, Canada, From 2012 to 2016.

BACKGROUND: The province of Manitoba, Canada, with a population of approximately 1.3 million, has been experiencing increased incidence of syphilis cases since 2015. In this study, we examined the detection of Treponema pallidum DNA in 354 clinical samples from 2012 to 2016, and determined molecular types and mutations conferring resistance to azithromycin in the polymerase chain reaction (PCR)-positive samples. METHODS: T. pallidum DNA detection was done by PCR amplification of tpp47, bmp, and polA genes. Syphilis serology results were reviewed for the PCR-positive cases. Molecular typing of syphilis strains was done by analysis of the T, pallidum arp, tpr, and tp0548 gene targets as well as partial sequencing of the 23S rRNA gene for azithromycin resistance. RESULTS: Of the 354 samples tested, 74 individual cases were PCR positive. A result from the treponemal antibody chemiluminescent microparticle immunoassay test was positive in 72 of these cases and that from the Venereal Disease Research Laboratory testing was positive in 66. Mutations conferring resistance to azithromycin were found in all 74 PCR-positive samples. Molecular typing was completed on 57 PCR-positive samples, and 12 molecular types were identified with 14d/g found in 63.2%. Increased strain diversity was observed with 8 molecular types detected in 2016, whereas only 2 to 3 types were found in 2012 to 2014. A patient with 2 episodes of infection 9 months apart caused by different molecular strain types was also identified. CONCLUSIONS: The finding of an increase in genetic diversity in the strains in this study and an increase in macrolide resistance compared with previous Canadian reports highlighted the need for continued surveillance including strain characterization.

Characteristics of invasive Haemophilus influenzae serotype a (Hia) from Nunavik, Canada and comparison with Hia strains in other North American Arctic regions.

OBJECTIVE: This study examines the microbiological characteristics of invasive Haemophilus influenae serotype a (Hia) isolates from Nunavik (northern Quebec), Canada. The relationship between invasive Hia isolates from Nunavik, Nunavut, Canada, and Alaska, USA will be discussed. METHODS: Twenty invasive Hia isolates were recovered from patients in Nunavik from 2010 to 2013 and characterized by biotype, multi-locus sequence typing, IS1016-bexA deletion, antibiotic susceptibility and pulsed field gel electrophoresis (PFGE). RESULTS: All 20 Hia isolates were biotype II, sequence type -23, did not have IS1016-bexA deletions and were susceptible to all antibiotics tested. PFGE showed only two patterns, with 19 isolates giving identical molecular fingerprints, and the remaining isolate gave a PFGE pattern >95% similar. CONCLUSION: One major clone of Hia appears to be causing invasive disease in Nunavik, Canada. Based on previous studies, Hia from Nunavut were also typed as ST-23, while invasive Hia isolates from Alaska belonged to either ST-23 or closely related STs. Thus invasive Hia in the North America Arctic belonged to the ST-23 clonal complex and lacked the IS1016-bexA partial deletion.

First Complete Genome Sequence of Haemophilus influenzae Serotype a.

Haemophilus influenzae is an important human pathogen that primarily infects small children. In recent years, H. influenzae serotype a has emerged as a significant cause of invasive disease among indigenous populations. Here, we present the first complete whole-genome sequence of H. influenzae serotype a.

Antigenic and genetic characterization of Bordetella pertussis recovered from Quebec, Canada, 2002-2014: detection of a genetic shift.

Despite vaccination, cyclical peaks of Bordetella pertussis incidence rates are still observed in Canada and other developed countries, making pertussis one of the most prevalent vaccine preventable bacterial diseases. In the postacellular vaccine era, evolution of bacterial strains has resulted in strains with altered vaccine antigens. Previous Canadian studies have focused on isolates mainly from the provinces of Ontario and Alberta, with only small numbers of isolates from other provinces. Therefore, in this study, we examined a larger sample (n = 52) of isolates from Quebec, Canada, between 2002 and 2014. Isolates were characterized by serotype, sequence type, and prevalence of pertactin deficiency. The Quebec isolates shared characteristics similar to other Canadian isolates and to isolates circulating globally. Although pertactin-deficient isolates were not present, a significant shift in sequence type was observed in more recent years. This study highlights the importance of continually monitoring disease-causing isolates to track evolutionary trends and gain a better understanding of the molecular epidemiology of pertussis in Canada.