HPV genotype-specific distribution and attributable risk in cervical intraepithelial neoplasia in a referral population with a history of LSIL.

BACKGROUND AND OBJECTIVE: CINtec PLUS and cobas HPV tests (Roche) were previously ascertained for triaging an LSIL referral population [1]. As part of this study, genotype-specific distribution and attributable risk of high-risk (HR)-HPV in cervical intraepithelial neoplasia (CIN) were determined. METHODS: Archived cervical specimens in ThinPrep PreservCyt (Hologic Inc) from the LSIL referral population (n= 533) were genotyped using the Anyplex II HPV HR test (Anyplex, Seegene Inc). Since the study specimens had been in storage in ambient temperature for 31-47 months since collection, Anyplex results were compared with that of the initial cobas testing of fresh specimens to validate the suitability and stability of specimens for the present study. RESULTS: Overall, Anyplex test was positive in 63% (336/533) vs. 55.7% (297/533) for cobas test. Anyplex test performed identical to cobas test identifying 93.2% (82/88) of ⩾CIN2/adenocarcinoma in situ (AIS). Anyplex test detected genotypes 16/18 in 15.7% (36/230) ⩽CIN1 vs. 45.5% (40/88) ⩾CIN2/AIS; the corresponding figures were 13.5% (31/230) and 45.5% (40/48) for the cobas test. Genotype 16 showed increasing attribution, 13.2% in CIN1, 27.1% in CIN2 and 40% in CIN3/AIS. Of the 12 other high-risk (OHR) types collectively identified by cobas, Anyplex test specifically detected, in decreasing order, genotypes 51, 31, 35, 56, 39, and 45 as the most frequent types, often in multiple-type infections, in 64.8% ⩾CIN2. Regardless, estimated attribution was evident for each of the 12 OHR types in ⩾CIN2. Multiple-type infections were more frequent than single-type infections in all CIN grades. CONCLUSIONS: Attributable risk of all HR-HPV genotypes targeted by both Anyplex and cobas tests was evident in ⩾CIN2/AIS Testing for these genotypes in HPV primary cervical screening and cytology triage could identify those at increased risk of cervical cancer and also be beneficial in the management of LSIL referral populations.

Comparison of CINtec PLUS cytology and cobas HPV test for triaging Canadian patients with LSIL cytology referred to colposcopy: A two-year prospective study.

OBJECTIVES & METHODS: CINtec PLUS and cobas HPV tests were compared for triaging patients referred to colposcopy with a history of LSIL cytology in a 2-year prospective study. Cervical specimens were tested once at enrollment, and test positivity rates determined. Test performance was ascertained with cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and CIN3 or worse (CIN3+) serving as clinical endpoints. RESULTS: In all ages, (19-76 years, n= 598), 44.3% tested CINtec PLUS positive vs. 55.4% HPV positive (p< 0.001). To detect CIN2+ (n= 99), CINtec PLUS was 81.8% sensitive vs. 93.9% for HPV testing (p= 0.009); genotype 16/18-specific sensitivity was 46.5%. Specificity was 52.9% vs. 36.6%, respectively (p< 0.001). In all ages, to detect CIN3+ (n= 44), sensitivity was 93.2% for both tests; genotype 16/18-specific sensitivity was 52.3%. Specificity was 48.4% for CINtec PLUS vs. 31.1% for HPV testing (p< 0.001). In patients < 30 years, CINtec was 91.7% sensitive vs 95.8% for HPV testing (p= 0.549). CONCLUSIONS: CINtec PLUS or cobas HPV test could serve as a predictor of CIN3+ with high sensitivity in patients referred to colposcopy with a history of LSIL regardless of age while significantly reducing the number of LSIL referral patients requiring further investigations and follow-up in colposcopy clinics.

Comparison of Alinity m HPV and cobas HPV assays on cervical specimens in diverse storage media.

OBJECTIVE: To assess the concordance of high-risk HPV (HR-HPV) testing with the Alinity assay on cervical samples collected with diverse collection/storage protocols (ThinPrep, SurePath, Cervicollect) and to assess inter-assay concordance of HR-HPV testing of cervical cell specimens with Alinity m HR HPV assay (Alinity) vs cobas® 4800 HPV assay (cobas). METHODS: Specimens were obtained from 560 women attending a Women's Health clinic. Two specimens were obtained from each woman with combinations of two of the three collection devices and aliquots were tested by the two assays. RESULTS: Alinity showed an agreement of 93.9%, Kappa = 0.89 (263/280) between ThinPrep and SurePath specimens; 97.5%, Kappa = 0.95 (347/356) and 92.9%, Kappa = 0.85 (104/112) between ThinPrep and SurePath aliquots taken before or after cytology processing, respectively. Cervi-Collect specimens showed an agreement of 94.6%, Kappa = 0.89 (265/280) with ThinPrep specimens. Compared to cobas, Alinity showed agreements of 94.3%, Kappa = 0.88 (395/419) and 91.8%, Kappa = 0.82 (257/280) between ThinPrep and SurePath specimens, respectively. Alinity and cobas detected genotypes 16/18 and other high-risk HPV types at similar rates and showed similar correlations with cytology grades. CONCLUSIONS: Compared to cobas, Alinity performed equally well for detecting HPV in cervical specimens obtained with ThinPrep and SurePath. The Cervi-Collect device compared well to the other collection methods. Alinity is a reliable assay for simultaneous detection of HPV-16/18 and other high-risk genotypes in cervical specimens.

Workflow and Throughput of Commercial Assays to Detect Mycoplasma genitalium and Macrolide Resistance-Mediating Mutations.

ABSTRACT: Aptima Mycoplasma genitalium (MG) required the shortest and STD6 the longest time to detect MG in clinical samples. ResistancePlus MG detected MG and macrolide resistance-mediating mutations simultaneously. Times were influenced by specimen numbers. M. genitalium positives from the other 2 assays required increased time for macrolide resistance-mediating mutation sequencing.

Comparison of Assays for the Diagnosis of Mycoplasma genitalium and Macrolide Resistance Mutations in Self-Collected Vaginal Swabs and Urine.

BACKGROUND: The objective was to compare commercial assays on clinical specimens for Mycoplasma genitalium (MG) detection and macrolide resistance mutation (MRM) frequency. METHODS: Three self-collected vaginal swabs (VS) and a first-void urine (FVU) from 300 consented women were tested by Aptima MG (AMG), ResistancePlus MG (RPMG) and Seeplex STD6 ACE (STD6) for detection of MG. Aptima MG and STD6 MG positives were tested for MRM using MG 23S rRNA polymerase chain reaction with Sanger sequencing (23SMGSS) compared with MRM determination in the RPMG assay. Unique AMG positives were tested with confirmatory Aptima assays. RESULTS: M. genitalium prevalence ranged from 7.1% to 19.7%, influenced by the assay used and the specimen tested. Overall agreements for MG detection were 96.3% (κ = 0.91) for VS and 93.3% (κ = 0.72) for FVU between AMG and RPMG with lower agreements with STD6. Using a rotating reference standard, sensitivities on VS and FVU were 100% and 100% for AMG, 100% and 83.3% for RPMG, and 54.2% and 48.4% for STD6. Specificities were high for RPMG and STD6 and AMG detected extra positives, most of which were confirmed. Macrolide resistance mutation frequency rates testing VS and FVU were 50% (24/48) and 58.1% (18/31) by RPMG compared with 52.5% (31/59) and 23.5% (12/51) by 23SMGSS. MRM overall agreements between RPMG and 23SMGSS were 73.2% (κ = 0.41) for VS and 76.0% (κ = 0.52) for FVU. CONCLUSIONS: Aptima MG detected more cases of MG infections. ResistancePlus MG detection was more effective on VS than on FVU. Seeplex STD6 ACE performance was inferior. The MRM detection component of RPMG agreed with results from 23SMGSS most of the time.

CINtec PLUS and cobas HPV testing for triaging Canadian women referred to colposcopy with a history of low-grade squamous intraepithelial lesion: Baseline findings.

OBJECTIVE AND METHODS: CINtec PLUS and cobas HPV tests were assessed for triaging women referred to colposcopy with a history of LSIL cytology. Both tests were performed at baseline using ThinPrep cervical specimens and biopsy confirmed cervical intraepithelial neoplasia grade 2 or worse (CIN2+) served as the clinical endpoint. RESULTS: In all ages, (19-76 years, n = 600), 44.3% (266/600) tested CINtec PLUS positive vs. 55.2% (331/600) HPV positive (p = 0.000). Based on 224 having biopsies, sensitivity to detect CIN2+ (n = 54) was 81.5% (44/54) for CINtec PLUS vs. 94.4% (51/54) for HPV testing (p = 0.039); specificities were, 52.4% (89/170) vs. 44.1% (75/170), respectively (p = 0.129). In women ≥30 years (n = 386), 41.2% (159/386) tested CINtec PLUS positive vs. 50.8% (196/386) HPV positive (p = 0.008). Based on 135 having biopsies, sensitivity to detect CIN2+ (n = 24) was 95.8% (23/24) for both CINtec PLUS and HPV tests; specificities were, 55.0% (61/111) vs. 50.5% (56/111), respectively (p = 0.503). CONCLUSIONS: For women referred to colposcopy with a history of LSIL cytology, CINtec PLUS or cobas HPV test could serve as a predictor of CIN2+ with high sensitivity, particularly in women ≥30 years. Either test can significantly reduce the number of women requiring further investigations and follow up in colposcopy clinics.

Performance of AmpFire HPV assay on neck cervical lymph node aspirate and oropharyngeal samples.

Early determination of high-risk human papillomaviruses causing oropharyngeal squamous cell carcinomas (OPSCC) may influence treatment. The objectives were to evaluate the performance of a new rapid isothermal nucleic acid amplification point of care HPV test (AmpFire HPV) on fine needle neck aspirates (FNA) of cervical lymph nodes and oropharyngeal swabs and saliva (OPS) which had been previously tested by the cobas HPV assay. The comparison was performed on 56 FNA and 81 OPS. The two assays showed strong agreement (94.6 %, K = 0.88) on FNA and fair agreement (65.4 %, K = 0.34) on OPS. AmpFire HPV performed on FNA demonstrated a sensitivity of 76.7 % and specificity of 81.8 % for the prediction of p16 antigens in OPSCC with results available in 1.5 h.

Mycoplasma genitalium, Chlamydia trachomatis, and Neisseria gonorrhoeae Detected With Aptima Assays Performed on Self-Obtained Vaginal Swabs and Urine Collected at Home and in a Clinic.

Self-obtained vaginal swabs, first-void urine and pooled specimens were collected at home and in a clinic. Percent prevalence and collection site concordance was 30.3 and 100 for Mycoplasma genitalium (74.4% azithromycin resistant) 15.1 and 96.7 for Chlamydia trachomatis and 6.6 and 100 for Neisseria gonorrhoeae (27% ciprofloxacin-resistant).

Treatment of first-void urine with Aptima Transfer Solution increases detection of high-risk HPV E6/E7 mRNA.

Because of its non-invasive nature urine testing may enable increased screening for HPV in women who avoid cervical sampling. Comparisons have shown fewer HPV positives in urine. The objectives were to compare first-void urine (FVU) treated with proteinase K (PK) to untreated FVU and cervical samples collected from women attending a colposcopy clinic using an Aptima HPV mRNA assay, and comparing the HPV rates to cytology and pathology results. Female FVU (n = 433) was treated with Aptima Transfer Solution (ATS) containing PK within 24 h or after months of storage. Untreated female FVU samples were HPV-positive in 20.8-27.6% compared to 34.4-45.6% of ATS-treated FVU and 44.9-48.4% of PreservCyt samples. Good overall agreement for HR-HPV detection between ATS-FVU and PreservCyt was observed (81.1%; k 0.63). Validation of ATS treatment was performed on 356 male FVU, detecting 6.7% HPV positive compared to 3.4% of untreated samples (p = 0.059). Although HPV presence in ATS FVU and PreservCyt samples were similar, significantly more women with abnormal cervical cytology and histopathology were HPV-positive in cervical specimens than in ATS-treated FVU.

Assessing the time dependence of prognostic values of cytology and human papillomavirus testing in cervical cancer screening.

Accurate assessment of risks for developing cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) after a given set of screening test results is instrumental to reaching valid conclusions and informing cervical cancer screening recommendations. Using data from the Canadian Cervical Cancer Screening Trial (CCCaST), we assessed prognostic values of enrollment screening test results to predict CIN2+ among women attending routine cervical screening using multivariable Cox proportional hazards (PH) regression and its flexible extension during each of two follow-up periods (protocol-defined and extended). Nonproportional (time-dependent (TD)) and/or nonlinear effects were modeled, as appropriate. Women with abnormal cytology had hazard ratios (HRs) for CIN2+ detection of 17.61 (95% CI: 11.25-27.57) and 10.46 (95% CI: 5.41-20.24) relative to women with normal cytology during the protocol-defined and extended follow-up periods, respectively. High-risk human papillomavirus (HR-HPV) positivity was an even stronger predictor of CIN2+ risk, with significant TD effects during both follow-up periods (p <0.001 for both TD effects). Risks among women co-testing HR-HPV+ with and without abnormal cytology (relative to women co-testing negative) were highest immediately after baseline, and decreased significantly thereafter (p <0.001 for both TD effects). HRs for HPV16+ and HPV18+ women (relative to those testing HR-HPV-) did not vary significantly over time (HR = 182.96; 95% CI: 95.16-351.77 and HR = 111.81; 95% CI: 44.60-280.31, respectively). Due to TD effects, conventional Cox model estimates considerably underestimated adjusted HRs associated with positive HR-HPV testing results early on in the follow-up periods.

Detection of cervical precancerous lesions with Aptima HPV assays using SurePath preservative fluid specimens.

SurePath specimens from women referred to colposcopy were treated with Aptima Transfer Solution (ATS) before testing in Aptima HPV (AHPV) and Aptima HPV 16, 18/45 (AHPV-GT) assays. Untreated SurePath specimens were tested with the cobas HPV test. PreservCyt specimens were assessed for cytology and tested with AHPV. High-grade cervical intraepithelial neoplasia lesions served as the reference standard. Excellent agreement (95.5%; k=0.91) was observed for ATS-treated SurePath specimens between Tigris and Panther systems and between the PreservCyt and ATS-treated SurePath specimens (91.1%, k=0.81) with the AHPV assay on Tigris. Agreement between the AHPV and cobas assays with SurePath specimens was substantial (89.9%, k=0.80). AHPV sensitivity for CIN2+(n=147) was 91.2% for SurePath and PreservCyt. Cobas HPV sensitivity was 93.9% for SurePath specimens. AHPV testing of SurePath specimens was more specific (59.4%) than cobas (54.7%) (p<0.001). Detection and genotyping showed similar absolute and relative risks. ATS-treated SurePath specimens tested with AHPV and AHPV-GT assays showed similar performance with greater specificity than cobas HPV on SurePath specimens. Similar overall results were seen using a CIN3 disease endpoint.

Mycoplasma genitalium Antibiotic Resistance-Mediating Mutations in Canadian Women With or Without Chlamydia Trachomatis Infection.

Testing remnant Aptima specimens from women infected with Chlamydia trachomatis detected 13.4% (53/396) with Mycoplasma genitalium compared with 5.4% (22/406) in matched C. trachomatis-negative women. Overall, 9.4% (provincial ranges of 3-20%) were infected with M. genitalium and resistance mediating mutations were found in 47.3% (26/55) to macrolides and 1.9% (1/53) to fluoroquinolones by sequencing.

Phylogenetic analysis of emergent Streptococcus pneumoniae serotype 22F causing invasive pneumococcal disease using whole genome sequencing.

Since implementation of the 13-valent polyvalent conjugate vaccine (PCV13) in Canada during 2010, the proportion of PCV13 serotypes causing invasive pneumococcal disease (IPD) has declined from 55% (n = 1492) in 2010 to 31% (n = 764) in 2014. A concurrent increase of non-PCV13 serotypes has occurred and 22F has become the most prevalent serotype in Canada increasing from 7% (n = 183) to 11% (n = 283). Core single nucleotide variant phylogenetic analysis was performed on 137 Streptococcus pneumoniae serotype 22F isolates collected across Canada from 2005-2015. Six phylogenetic lineages (n = 117) were identified among a serotype 22F/ST433 clonal complex (CC), including a recently expanding erythromycin-resistant clone. Erythromycin-resistance was observed in 25 isolates possessing ermB, mef or a 23S rRNA A2061G point mutation; 2 penicillin-resistant isolates had recombinant pbp1a, pbp2a and/or pbp2x; 3 tetracycline-resistant isolates contained tetM; and 1 isolate was multidrug-resistant. Virulence factor analysis indicated a high level of homogeneity among the 22F/ST433 clonal complex strains. A group of 6 phylogenetic outlier strains had differing MLST, antimicrobial resistance and molecular profiles suggestive of capsule switching events. While capsule switch events among S. pneumoniae serotype 22F has been observed, increasing prevalence of S. pneumoniae serotype 22F can be attributed to an evolving homogenous clone expanding nationally through local transmission events.

Approaches for triaging women who test positive for human papillomavirus in cervical cancer screening.

Substantial evidence exists to support the introduction of molecular testing for human papillomavirus (HPV) as the primary technology in cervical cancer screening. While HPV testing is much more sensitive than cytology for detection of high-grade precancerous lesions, it is less specific. To improve efficiency, it is therefore recommended that a specific test (like cytology) be used in triaging HPV positive women to colposcopy. A number of studies have been conducted that support the use of cytology alone or in conjunction with HPV genotyping for triage. The decision to incorporate genotyping also depends on the commercial HPV test that is selected since not all tests provide results for certain individual high-risk types. Regardless of whether policy officials decide to adopt a triage approach that incorporates genotyping, the use of liquid based cytology (LBC) may also improve screening performance by reducing diagnostic delays. With LBC, the same cell suspension from a single collection may be used for HPV testing and a smear can be immediately prepared if HPV status is positive. This was a critical lesson from a community based demonstration project in Montreal (VASCAR study), where conventional cytology exists and specimen co-collection was not permitted for ethical reasons, requiring HPV positive women to return for an additional screening visit prior to colposcopy.

Introduction of molecular HPV testing as the primary technology in cervical cancer screening: Acting on evidence to change the current paradigm.

Since being introduced in the 1940s, cervical cytology - despite its limitations - has had unequivocal success in reducing cervical cancer burden in many countries. However, we now know that infection with human papillomavirus (HPV) is a necessary cause of cervical cancer and there is overwhelming evidence from large-scale clinical trials, feasibility studies and real-world experience that supports the introduction of molecular testing for HPV as the primary technology in cervical cancer screening (i.e., "HPV primary screening"). While questions remain about the most appropriate age groups for screening, screening interval and triage approach, these should not be considered barriers to implementation. Many countries are in various stages of adopting HPV primary screening, whereas others have not taken any major steps towards introduction of this approach. As a group of clinical experts and researchers in cervical cancer prevention from across Canada, we have jointly authored this comprehensive examination of the evidence to implement HPV primary screening. Our intention is to create a common understanding among policy makers, agencies, clinicians, researchers and other stakeholders about the evidence concerning HPV primary screening to catalyze the adoption of this improved approach to cervical cancer prevention. With the first cohort of vaccinated girls now turning 21, the age when routine screening typically begins, there is increased urgency to introduce HPV primary screening, whose performance may be less adversely affected compared with cervical cytology as a consequence of reduced lesion prevalence post-vaccination.

Comparison of cobas 4800, m2000, Viper XTR, and Infinity 80 Automated Instruments When Processing Urine Specimens for the Diagnosis of Chlamydia trachomatis and Neisseria gonorrhoeae.

OBJECTIVES: North American and European advisory groups recommend testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) with nucleic acid amplification tests. Testing is often performed on automated instruments. The objectives of this study were to process urines for the diagnosis of CT and NG and to examine workflow procedures and outcomes. METHODS: While processing 1, 24, 48, 96, and 192 urine specimens on 3 batch-mode systems which use 96-well plates: cobas 4800, m2000, and Viper XTR and the random access cartridge testing GeneXpert Infinity 80, we measured assay performance, hands-on time for processing and maintenance, reagents and plastics consumption, time required to obtain results, and testing accuracy. RESULTS: The Infinity 80 required the least hands-on time for single specimens and smaller batches, whereas the Viper XTR and m2000 required the most hands-on time for all batch sizes. Cumulative daily, weekly, and monthly maintenance was highest for the Viper XTR and lowest for Infinity 80. All batch-mode instruments consumed large amounts of disposables. Time to results was shortest for the Infinity 80, and the Viper XTR provided the shortest time for the batch-mode instruments. All systems showed similar diagnostic accuracy. CONCLUSIONS: Because detection performances were similar, issues of hands-on time, maintenance, time to results, and consumables are important operational factors for the diagnosis and treatment of CT/NG infections.

Comparison of Triage Strategies for HPV-Positive Women: Canadian Cervical Cancer Screening Trial Results.

Background: High-risk human papillomavirus (HR-HPV) testing has become a preferred cervical cancer screening strategy in some countries due to its superior sensitivity over cytology-based methods for identifying cervical intraepithelial neoplasia of grade 2 or worse (CIN2+). Improved sensitivity has been accompanied by reductions in specificity and concerns regarding overscreening and overtreatment of women with transient or nonprogressing HR-HPV infections. Triage of HR-HPV+ women to colposcopy is, thus, warranted for appropriate management and treatment.Methods: Using data from the Canadian Cervical Cancer Screening Trial (CCCaST), we compared the performance of cytology and HR-HPV strategies to detect CIN2+ among HR-HPV+ women (age, 30-69 years). Colposcopy referral rates and performance gains from adding other HR-HPV genotypes to HPV16/18+ triage were also evaluated.Results: A strategy referring all women HPV16/18+ and HPV16/18-, but with atypical squamous cells of undetermined significance or worse cytology (ASC-US+) had the highest sensitivity [82.5%; 95% confidence interval (CI), 70.9%-91.0%] but yielded the highest colposcopy referral rate. HPV16/18+ triage was the next most sensitive strategy (64.1%; 95% CI, 51.1%-75.7%). Low-grade squamous intraepithelial lesion or worse cytology (LSIL+) triage yielded a low sensitivity (32.8%; 95% CI, 21.9%-45.4%) but had the most favorable specificity (93.6%; 95% CI, 91.0%-95.6%), positive predictive value (41.5%; 95% CI, 28.1%-55.9%), and colposcopy referral rate of strategies examined. HPV viral load triage strategies did not perform optimally overall. Inclusion of HR-HPV genotypes 31 and 52 to HPV16/18+ triage provided the highest sensitivities.Conclusion: Concerns surrounding HPV-based screening can be effectively mitigated via triage.Impact: Balancing the benefits of HPV-based primary cervical screening with informed management recommendations for HR-HPV+ women may decide the success of its widening utilization. Cancer Epidemiol Biomarkers Prev; 26(6); 923-9. ©2017 AACR.

Human papillomavirus testing versus cytology in primary cervical cancer screening: End-of-study and extended follow-up results from the Canadian cervical cancer screening trial.

The Canadian Cervical Cancer Screening Trial was a randomized controlled trial comparing the performance of human papillomavirus (HPV) testing and Papanicolaou cytology to detect cervical intraepithelial neoplasia of grades 2 or worse (CIN2+) among women aged 30-69 years attending routine cervical cancer screening in Montreal and St. John's, Canada (n = 10,154). We examined screening and prognostic values of enrollment cytologic and HPV testing results. Extended follow-up data were available for St. John's participants (n = 5,754; 501,682.6 person-months). HPV testing detected more CIN2+ than cytology during protocol-defined (82.9 vs. 44.4%) and extended (54.2 vs. 19.3%) follow-up periods, respectively. Three-year risks ranged from 0.87% (95% CI: 0.37-2.05) for HPV-/Pap- women to 35.77% (95% CI: 25.88-48.04) for HPV+/Pap+ women. Genotype-specific risks ranged from 0.90% (95% CI: 0.40-2.01) to 43.84% (95% CI: 32.42-57.24) among HPV- and HPV16+ women, respectively, exceeding those associated with Pap+ or HPV+ results taken individually or jointly. Ten-year risks ranged from 1.15% (95% CI: 0.60-2.19) for HPV-/Pap- women to 26.05% (95% CI: 15.34-42.13) for HPV+/Pap+ women and genotype-specific risks ranged from 1.13% (95% CI: 0.59-2.14) to 32.78% (95% CI: 21.15-48.51) among women testing HPV- and HPV16+, respectively. Abnormal cytology stratified risks most meaningfully for HPV+ women. Primary HPV testing every 3 years provided a similar or greater level of reassurance against disease risks as currently recommended screening strategies. HPV-based cervical screening may allow for greater disease detection than cytology-based screening and permit safe extensions of screening intervals; genotype-specific testing could provide further improvement in the positive predictive value of such screening.

Phenotypic H-Antigen Typing by Mass Spectrometry Combined with Genetic Typing of H Antigens, O Antigens, and Toxins by Whole-Genome Sequencing Enhances Identification of Escherichia coli Isolates.

Mass spectrometry-based phenotypic H-antigen typing (MS-H) combined with whole-genome-sequencing-based genetic identification of H antigens, O antigens, and toxins (WGS-HOT) was used to type 60 clinical Escherichia coli isolates, 43 of which were previously identified as nonmotile, H type undetermined, or O rough by serotyping or having shown discordant MS-H and serotyping results. Whole-genome sequencing confirmed that MS-H was able to provide more accurate data regarding H antigen expression than serotyping. Further, enhanced and more confident O antigen identification resulted from gene cluster based typing in combination with conventional typing based on the gene pair comprising wzx and wzy and that comprising wzm and wzt The O antigen was identified in 94.6% of the isolates when the two genetic O typing approaches (gene pair and gene cluster) were used in conjunction, in comparison to 78.6% when the gene pair database was used alone. In addition, 98.2% of the isolates showed the existence of genes for various toxins and/or virulence factors, among which verotoxins (Shiga toxin 1 and/or Shiga toxin 2) were 100% concordant with conventional PCR based testing results. With more applications of mass spectrometry and whole-genome sequencing in clinical microbiology laboratories, this combined phenotypic and genetic typing platform (MS-H plus WGS-HOT) should be ideal for pathogenic E. coli typing.