Genetic and Phenotypic Characterization of the First Canadian Case of Ambler Class A Carbapenemase FRI-8.

This study investigated the mechanism of carbapenem resistance in an Enterobacter cloacae complex positive by the modified carbapenem inactivation method (mCIM) but negative by the Rosco Neo-Rapid Carb Kit, ß CARBA, and conventional PCR for common carbapenemase genes (KPC, NDM, OXA-48, IMP, VIM, GES, and IMI/NMC). Using whole genome sequencing (WGS) data we confirmed the identification of Enterobacter asburiae (ST1639) and the presence of blaFRI-8 located on a 148kb IncFII(Yp) plasmid. This is the first occurrence of a clinical isolate harboring the FRI-8 carbapenemase and the second occurrence of FRI in Canada. This study highlights the need to use both WGS and phenotypic screening methods for detection of carbapenemase-producing strains if we consider the growing diversity of carbapenemases.

A Burkholderia stabilis outbreak associated with the use of ultrasound gel in multiple healthcare centres in Montréal, Canada, May-October 2021.

Background: Burkholderia stabilis is a non-fermenting, gram-negative bacteria that has previously been implicated in multiple nosocomial outbreaks through the use of contaminated medical devices and substances. This article reports on an outbreak of B. stabilis infections and colonizations, involving 11 patients from five acute care hospitals in Montréal, Canada. Methods: One sample was not available for testing, but the remaining 10 isolates (91%) were sent for phylogenetic testing. Medical materials and the patients' environments were also sampled and cultured. Samples were tested using pulsed field gel electrophoresis and multilocus sequence typing. Results: The outbreak was found to be associated with the use of intrinsically contaminated non-sterile ultrasound gel. Relatedness of the gel's and the patients' B. stabilis strains was demonstrated using gel electrophoresis and multilocus sequence typing analyses. The investigation was concluded with a prompt recall of the product, and the outbreak was declared over by the end of October 2021. Conclusion: Contaminated non-sterile gel caused infections and pseudo-infections in several patients.

Natural spring water gargle samples as an alternative to nasopharyngeal swabs for SARS-CoV-2 detection using a laboratory-developed test.

The objective of this study was to validate the use of spring water gargle (SWG) as an alternative to oral and nasopharyngeal swab (ONPS) for SARS-CoV-2 detection with a laboratory-developed test. Healthcare workers and adults from the general population, presenting to one of two COVID-19 screening clinics in Montréal and Québec City, were prospectively recruited to provide a gargle sample in addition to the standard ONPS. The paired specimens were analyzed using thermal lysis followed by a laboratory-developed nucleic acid amplification test (LD-NAAT) to detect SARS-CoV-2, and comparative performance analysis was performed. An individual was considered infected if a positive result was obtained on either sample. A total of 1297 adult participants were recruited. Invalid results (n = 18) were excluded from the analysis. SARS-CoV-2 was detected in 144/1279 (11.3%) participants: 126 from both samples, 15 only from ONPS, and 3 only from SWG. Overall, the sensitivity was 97.9% (95% CI: 93.7-99.3) for ONPS and 89.6% (95% CI: 83.4-93.6; p = 0.005) for SWG. The mean ONPS cycle threshold (Ct ) value was significantly lower for the concordant paired samples as compared to discordant ones (22.9 vs. 32.1; p < 0.001). In conclusion, using an LD-NAAT with thermal lysis, SWG is a less sensitive sampling method than the ONPS. However, the higher acceptability of SWG might enable a higher rate of detection from a population-based perspective. Nonetheless, in patients with a high clinical suspicion of COVID-19, a repeated analysis with ONPS should be considered. The sensitivity of SWG using NAAT preceded by chemical extraction should be evaluated.

Analysis of an IncR Plasmid Carrying blaNDM-1 Linked to an Azithromycin Resistance Region in Enterobacter hormaechei Involved in an Outbreak in Quebec.

In the context of a recent rise in prevalence of NDM-encoding carbapenemase-producing Enterobacterales (CPE) in the province of QC, Canada, the genetic environment of blaNDM-1 was investigated. Three NDM-producing clinical isolates of Enterobacter hormaechei recovered from hospitalized patients involved in a putative outbreak were further characterized by whole-genome sequencing (WGS). Two isolates were confirmed by pulsed-field gel electrophoresis and WGS to be closely related. In addition to a ∼128 kb IncFII conjugative multidrug-resistance (MDR) plasmid, these isolates possessed a ∼45 kb mobilizable IncR MDR plasmid containing 2 MDR regions: a complex class 1 integron harboring blaNDM-1 and 7 other AMR genes, and the IS26-mph(A)-mrx-mphR(A)-IS6100 azithromycin resistance unit. The predicted antimicrobial resistance (AMR) genes correlated with the antimicrobial susceptibility testing results. The multidrug-resistant phenotype in addition to the presence of two important mobile genetic elements, suggest a potent role as a reservoir of antibiotic resistance for such a small IncR plasmid. IMPORTANCE Analyzing the genetic environment of clinically relevant MDR genes can provide information on the way in which such genes are maintained and disseminated. Understanding this phenomenon is of interest for clinicians as it can also provide insight on where these genes might have been sourced, possibly supporting outbreak investigations.

Source Tracking Based on Core Genome SNV and CRISPR Typing of Salmonella enterica Serovar Heidelberg Isolates Involved in Foodborne Outbreaks in Québec, 2012.

Whole-genome sequencing (WGS) is the method of choice for bacterial subtyping and it is rapidly replacing the more traditional methods such as pulsed-field gel electrophoresis (PFGE). Here we used the high-resolution core genome single nucleotide variant (cgSNV) typing method to characterize clinical and food from Salmonella enterica serovar Heidelberg isolates in the context of source attribution. Additionally, clustered regularly interspaced short palindromic repeats (CRISPR) analysis was included to further support this method. Our results revealed that cgSNV was highly discriminatory and separated the outbreak isolates into distinct clusters (0-4 SNVs). CRISPR analysis was also able to distinguish outbreak strains from epidemiologically unrelated isolates. Specifically, our data clearly demonstrated the strength of these two methods to determine the probable source(s) of a 2012 epidemiologically characterized outbreak of S. Heidelberg. Using molecular cut-off of 0-10 SNVs, the cgSNV analysis of 246 clinical and food isolates of S. Heidelberg collected in Québec, in the same year of the outbreak event, revealed that retail and abattoir chicken isolates likely represent an important source of human infection to S. Heidelberg. Interestingly, the isolates genetically related by cgSNV also harbored the same CRISPR as outbreak isolates and clusters. This indicates that CRISPR profiles can be useful as a complementary approach to determine source attribution in foodborne outbreaks. Use of the genomic analysis also allowed to identify a large number of cases that were missed by PFGE, indicating that most outbreaks are probably underestimated. Although epidemiological information must still support WGS-based results, cgSNV method is a highly discriminatory method for the resolution of outbreak events and the attribution of these events to their respective sources. CRISPR typing can serve as a complimentary tool to this analysis during source tracking.

HIV-1 Envelope Glycoprotein Amino Acids Signatures Associated with Clade B Transmitted/Founder and Recent Viruses.

BACKGROUND: HIV-1 transmitted/founder viruses (TF) are selected during the acute phase of infection from a multitude of virions present during transmission. They possess the capacity to establish infection and viral dissemination in a new host. Deciphering the discrete genetic determinant of infectivity in their envelope may provide clues for vaccine design. METHODS: One hundred twenty-six clade B HIV-1 consensus envelope sequences from untreated acute and early infected individuals were compared to 105 sequences obtained from chronically infected individuals using next generation sequencing and molecular analyses. RESULTS: We identified an envelope amino acid signature associated with TF viruses. They are more likely to have an isoleucine (I) in position 841 instead of an arginine (R). This mutation of R to I (R841I) in the gp41 cytoplasmic tail (gp41CT), specifically in lentivirus lytic peptides segment 1 (LLP-1), is significantly enriched compared to chronic viruses (OR = 0.2, 95% CI (0.09, 0.44), p = 0.00001). Conversely, a mutation of lysine (K) to isoleucine (I) located in position six (K6I) of the envelope signal peptide was selected by chronic viruses and compared to TF (OR = 3.26, 95% CI (1.76-6.02), p = 0.0001). CONCLUSIONS: The highly conserved gp41 CT_ LLP-1 domain plays a major role in virus replication in mediating intracellular traffic and Env incorporation into virions in interacting with encoded matrix protein. The presence of an isoleucine in gp41 in the TF viruses' envelope may sustain its role in the successful establishment of infection during the acute stage.

A Short-Term Assessment of Nascent HIV-1 Transmission Clusters Among Newly Diagnosed Individuals Using Envelope Sequence-Based Phylogenetic Analyses.

The identification of transmission clusters (TCs) of HIV-1 using phylogenetic analyses can provide insights into viral transmission network and help improve prevention strategies. We compared the use of partial HIV-1 envelope fragment of 1,070 bp with its loop 3 (108 bp) to determine its utility in inferring HIV-1 transmission clustering. Serum samples of recently (n = 106) and chronically (n = 156) HIV-1-infected patients with status confirmed were sequenced. HIV-1 envelope nucleotide-based phylogenetic analyses were used to infer HIV-1 TCs. Those were constructed using ClusterPickerGUI_1.2.3 considering a pairwise genetic distance of ≤10% threshold. Logistic regression analyses were used to examine the relationship between the demographic factors that were likely associated with HIV-1 clustering. Ninety-eight distinct consensus envelope sequences were subjected to phylogenetic analyses. Using a partial envelope fragment sequence, 42 sequences were grouped into 15 distinct small TCs while the V3 loop reproduces 10 clusters. The agreement between the partial envelope and the V3 loop fragments was significantly moderate with a Cohen's kappa (κ) coefficient of 0.59, p < .00001. The mean age (<38.8 years) and HIV-1 B subtype are two factors identified that were significantly associated with HIV-1 transmission clustering in the cohort, odds ratio (OR) = 0.25, 95% confidence interval (CI, 0.04-0.66), p = .002 and OR: 0.17, 95% CI (0.10-0.61), p = .011, respectively. The present study confirms that a partial fragment of the HIV-1 envelope sequence is a better predictor of transmission clustering. However, the loop 3 segment may be useful in screening purposes and may be more amenable to integration in surveillance programs.

Genomic Investigation of the Emergence of Invasive Multidrug-Resistant Salmonella enterica Serovar Dublin in Humans and Animals in Canada.

Salmonella enterica subsp. enterica serovar Dublin is a zoonotic pathogen that often leads to invasive bloodstream infections in humans that are multidrug resistant. Described here are the results of Canadian national surveillance of S Dublin from 2003 to 2015 in humans and bovines, principally collected through the Canadian Integrated Program for Antibiotic Resistance Surveillance (CIPARS). An increase in human infections due to multidrug-resistant (MDR) S Dublin was observed in 2010, many of which were bloodstream infections. Phylogenomic analysis of human and bovine isolates revealed a closely related network that differed by only 0 to 17 single nucleotide variants (SNVs), suggesting some potential transmission between humans and bovines. Phylogenomic comparison of global publicly available sequences of S Dublin showed that Canadian isolates clustered closely with those from the United States. A high correlation between phenotypic and genotypic antimicrobial susceptibility was observed in Canadian isolates. IS26 replication was widespread among U.S. and Canadian isolates and caused the truncation and inactivation of the resistance genes strA and blaTEM-1B A hybrid virulence and MDR plasmid (pN13-01125) isolated from a Canadian S Dublin isolate was searched against NCBI SRA data of bacteria. The pN13-01125 coding sequences were found in 13 Salmonella serovars, but S Dublin appears to be a specific reservoir. In summary, we have observed the rise of invasive MDR S Dublin in humans in Canada and found that they are closely related to bovine isolates and to American isolates in their mobile and chromosomal contents.

Evaluation of the Bio-Rad Geenius HIV 1/2 Assay as Part of a Confirmatory HIV Testing Strategy for Quebec, Canada: Comparison with Western Blot and Inno-Lia Assays.

The rapid confirmatory Bio-Rad Geenius HIV 1/2 assay was evaluated as an alternative to the HIV-1 Western blot (WB) confirmatory assay. A total of 370 retrospective samples collected from 356 patients were tested. Sensitivity of the Geenius assay to detect HIV-1 and HIV-2 infections was 100% and 97%, respectively, and that of the WB assay was 86% and 39%, respectively. Geenius reduced the number of indeterminate results by 85% and exhibited a differentiation capacity for HIV-1 and HIV-2 of 100% and 89%, respectively. Three of 10 patients presenting with an early HIV infection (1 to 2 weeks before seroconversion by WB) were positive using Geenius. None of the HIV-negative samples were positive using Geenius or WB. However, 7% and 10% of them were indeterminate with Geenius and WB, respectively, leading to a specificity rate of 93% for Geenius and 90% for WB. Ninety cadaveric samples (54 negative, 23 HIV-1 positive, and 3 HIV-1 indeterminate) were tested with Geenius, leading to a sensitivity of 100%, a specificity of 96%, and an indeterminate rate of 4%. Our results indicate that the Bio-Rad Geenius HIV 1/2 rapid test exhibits better sensitivity to detect HIV-1 infections and better performance than WB to confirm and differentiate between HIV-1 and HIV-2 infections. The performance of this new confirmatory assay to detect early infections, to reduce the rate of indeterminate status, and to confirm HIV-1 infection in cadaveric blood samples makes Geenius a potent reliable alternative to the WB.

Genetic Mechanisms behind the Spread of Reduced Susceptibility to Azithromycin in Shigella Strains Isolated from Men Who Have Sex with Men in Québec, Canada.

We analyzed 254 Shigella species isolates collected in Québec, Canada, during 2013 and 2014. Overall, 23.6% of isolates showed reduced susceptibility to azithromycin (RSA) encoded by mphA (11.6%), ermB (1.7%), or both genes (86.7%). Shigella strains with RSA were mostly isolated from men who have sex with men (68.8% or higher) from the Montreal region. A complete sequence analysis of six selected plasmids from Shigella sonnei and different serotypes of Shigella flexneri emphasized the role of IS26 in the dissemination of RSA.

Improvement of reverse sequence algorithm for syphilis diagnosis using optimal treponemal screening assay signal-to-cutoff ratio.

BACKGROUND: Although reverse sequence algorithms (RSA) for syphilis screening are performing well, they still have to rely on treponemal confirmatory tests at least for sera reactive by enzyme immunoassay/chemiluminescence immunoassay (EIA/CIA) and unreactive by rapid plasma reagin (RPR). Quebec's laboratory network previously showed that 3.3% of EIA/CIA reactive and weakly-reactive RPR samples (RPR titer of 1 to 4) would have been misclassified as syphilis cases if a treponemal confirmatory test had not been performed. OBJECTIVES: To correlate the magnitude of signal-to-cutoff (S/CO) ratios of the 4 most used commercial first-line EIA/CIA kits in Quebec with syphilis confirmation results and establish a S/CO value above which treponemal confirmation would not be required. METHODS: Serum samples from previously undiagnosed individuals (n = 7 404) obtained between January 2014 and February 2017 that were reactive by EIA/CIA and either negative by RPR or reactive with a low titer (1 to 4) were included in the study. All samples were tested with Treponema pallidum particle agglutination (TP-PA) and, if negative or inconclusive, with a line immunoassay (LIA). Syphilis infection confirmation was defined by a reactive TP-PA or LIA. Logistic regression analysis was used to determine S/CO values (95% CI lower bound = 0.98) above which confirmation would not be required. The four kits studied were Architect TP, BioPlex IgG, Syphilis EIA II, and Trep-Sure. RESULTS: Of 2609 reactive EIA/CIA specimens tested for the determination of S/CO values, 1730 (66%) were confirmed as true syphilis cases. Confirmation rate was significantly higher in samples with low-titer positive RPR (92%) than with negative RPR samples (54%); p<0.01. A linear probability model (95% CI lower bound = 0.98) predicted the S/CO value above which a confirmation would no longer be needed for the Architect TP (16.4), Bioplex IgG (7.4) and Trep-Sure (24.6). No linearity was observed between the S/CO value of Syphilis EIA II and the confirmation rate. The validity of the predicted S/CO values was investigated using 4 795 specimens. The use of an S/CO value of 16.4 with the Architect TP kit and of 24.6 for the Trep-Sure kit would obviate the need for confirmation of 18.5% and 13.2% of sera from the all RPR subgroup, respectively. For the BioPlex IgG kit, 81.1% of sera would not require confirmation when using the S/CO value of 7.4 in the low titer RPR subgroup. CONCLUSION: Signal-to-cut-off values could be used to identify sera that do not require extra treponemal confirmation for 3 of the 4 most used first-line EIA/CIA kits in Quebec. Using these values in our current reverse screening algorithm (RSA) would avoid the need for confirmatory tests in 14 to 20% of sera, a proportion that could reach 75% among low-titer RPR.

Comparison of advanced whole genome sequence-based methods to distinguish strains of Salmonella enterica serovar Heidelberg involved in foodborne outbreaks in Québec.

Salmonella enterica serovar Heidelberg (S. Heidelberg) is one of the top serovars causing human salmonellosis. This serovar ranks second and third among serovars that cause human infections in Québec and Canada, respectively, and has been associated with severe infections. Traditional typing methods such as PFGE do not display adequate discrimination required to resolve outbreak investigations due to the low level of genetic diversity of isolates belonging to this serovar. This study evaluates the ability of four whole genome sequence (WGS)-based typing methods to differentiate among 145 S. Heidelberg strains involved in four distinct outbreak events and sporadic cases of salmonellosis that occurred in Québec between 2007 and 2016. Isolates from all outbreaks were indistinguishable by PFGE. The core genome single nucleotide variant (SNV), core genome multilocus sequence typing (MLST) and whole genome MLST approaches were highly discriminatory and separated outbreak strains into four distinct phylogenetic clusters that were concordant with the epidemiological data. The clustered regularly interspaced short palindromic repeats (CRISPR) typing method was less discriminatory. However, CRISPR typing may be used as a secondary method to differentiate isolates of S. Heidelberg that are genetically similar but epidemiologically unrelated to outbreak events. WGS-based typing methods provide a highly discriminatory alternative to PFGE for the laboratory investigation of foodborne outbreaks.

Impact of the choice of reference genome on the ability of the core genome SNV methodology to distinguish strains of Salmonella enterica serovar Heidelberg.

Salmonella enterica serovar Heidelberg (S. Heidelberg) is one of the top serovars causing human salmonellosis. The core genome single nucleotide variant pipeline (cgSNV) is one of several whole genome based sequence typing methods used for the laboratory investigation of foodborne pathogens. SNV detection using this method requires a reference genome. The purpose of this study was to investigate the impact of the choice of the reference genome on the cgSNV-informed phylogenetic clustering and inferred isolate relationships. We found that using a draft or closed genome of S. Heidelberg as reference did not impact the ability of the cgSNV methodology to differentiate among 145 S. Heidelberg isolates involved in foodborne outbreaks. We also found that using a distantly related genome such as S. Dublin as choice of reference led to a loss in resolution since some sporadic isolates were found to cluster together with outbreak isolates. In addition, the genetic distances between outbreak isolates as well as between outbreak and sporadic isolates were overall reduced when S. Dublin was used as the reference genome as opposed to S. Heidelberg.

Comparison of sequential multiplex PCR, sequetyping and whole genome sequencing for serotyping of Streptococcus pneumoniae.

Streptococcus pneumoniae is one of the major causes of pneumonia, meningitis and other pneumococcal infections in young children and elders. Determination of circulating S. pneumoniae serotypes is an essential service by public health laboratories for the monitoring of putative serotype replacement following the introduction of pneumococcal conjugate vaccines (PCVs) and of the efficacy of the immunization program. The Quellung method remains the gold standard for typing S. pneumoniae. Although this method is very effective, it is also costly, time consuming and not totally reliable due to its subjective nature. The objectives of this study were to test and evaluate the efficiency of 3 different molecular methods compared to the Quellung method. Sequential multiplex PCR, sequetyping and whole genome sequencing (WGS) were chosen and tested using a set of diverse S. pneumoniae. One-hundred and eighteen isolates covering 83 serotypes were subjected to multiplex PCR and sequetyping while 88 isolates covering 53 serotypes were subjected to WGS. Sequential multiplex PCR allowed the identification of a significant proportion (49%) of serotypes at the serogroup or subset level but only 27% were identified at the serotype level. Using WGS, 55% to 60% of isolates were identified at the serotype level depending on the analysis strategy used. Finally, sequetyping demonstrated the lowest performance, with 17% of misidentified serotypes. The use of Jin cpsB database instead of the GenBank database slightly improved results but did not significantly impact the efficiency of sequetyping. Although none of these molecular methods may currently replace the Quellung method, WGS remains the most promising molecular pneumococcal serotyping method.

HIV-1 envelope sequence-based diversity measures for identifying recent infections.

Identifying recent HIV-1 infections is crucial for monitoring HIV-1 incidence and optimizing public health prevention efforts. To identify recent HIV-1 infections, we evaluated and compared the performance of 4 sequence-based diversity measures including percent diversity, percent complexity, Shannon entropy and number of haplotypes targeting 13 genetic segments within the env gene of HIV-1. A total of 597 diagnostic samples obtained in 2013 and 2015 from recently and chronically HIV-1 infected individuals were selected. From the selected samples, 249 (134 from recent versus 115 from chronic infections) env coding regions, including V1-C5 of gp120 and the gp41 ectodomain of HIV-1, were successfully amplified and sequenced by next generation sequencing (NGS) using the Illumina MiSeq platform. The ability of the four sequence-based diversity measures to correctly identify recent HIV infections was evaluated using the frequency distribution curves, median and interquartile range and area under the curve (AUC) of the receiver operating characteristic (ROC). Comparing the median and interquartile range and evaluating the frequency distribution curves associated with the 4 sequence-based diversity measures, we observed that the percent diversity, number of haplotypes and Shannon entropy demonstrated significant potential to discriminate recent from chronic infections (p<0.0001). Using the AUC of ROC analysis, only the Shannon entropy measure within three HIV-1 env segments could accurately identify recent infections at a satisfactory level. The env segments were gp120 C2_1 (AUC = 0.806), gp120 C2_3 (AUC = 0.805) and gp120 V3 (AUC = 0.812). Our results clearly indicate that the Shannon entropy measure represents a useful tool for predicting HIV-1 infection recency.

A Syst-OMICS Approach to Ensuring Food Safety and Reducing the Economic Burden of Salmonellosis.

The Salmonella Syst-OMICS consortium is sequencing 4,500 Salmonella genomes and building an analysis pipeline for the study of Salmonella genome evolution, antibiotic resistance and virulence genes. Metadata, including phenotypic as well as genomic data, for isolates of the collection are provided through the Salmonella Foodborne Syst-OMICS database (SalFoS), at https://salfos.ibis.ulaval.ca/. Here, we present our strategy and the analysis of the first 3,377 genomes. Our data will be used to draw potential links between strains found in fresh produce, humans, animals and the environment. The ultimate goals are to understand how Salmonella evolves over time, improve the accuracy of diagnostic methods, develop control methods in the field, and identify prognostic markers for evidence-based decisions in epidemiology and surveillance.

Performance of Bio-Rad and Limiting Antigen Avidity Assays in Detecting Recent HIV Infections Using the Quebec Primary HIV-1 Infection Cohort.

BACKGROUND: Accurate and practical biologic tools to estimate HIV incidence is crucial to better monitor the epidemic and evaluate the effectiveness of HIV prevention and treatment programs. METHODS: We evaluated two avidity assays to measure recent HIV infection: the Sedia HIV-1 LAg-Avidity EIA (Sedia Biosciences, Portland) and the Centers for Disease Control and Prevention (CDC)-modified Bio-Rad-Avidity assay (Bio-Rad Laboratories, Mississauga, ON). Longitudinal specimens (n = 473) obtained from 123 treatment-naive seroconverted individuals enrolled in the Primary HIV-1 Infection (PHI) cohort of Quebec were used to determine the average time an individual is considered to be recently infected (mean duration of recent infection; MDRI), for the two avidity assays alone and in combination using a nonparametric survival method analysis. A total of 420 specimens from individuals with established HIV infection (90 individuals from the PHI cohort of Quebec and 330 individuals from the Laboratoire de santé publique du Quebec (LSPQ) serobank) were also tested to investigate false recency rate (FRR). RESULTS: The CDC-modified Bio-Rad-Avidity gave an estimated MDRI of 234 days (95% CI 220-249) at the avidity index cutoff of 30% while the Sedia-LAg-Avidity assay gave an estimated MDRI of 120 days (95% CI 109-132) at the normalized optical density (ODn) cutoff of 1.5. The FRR among individuals with established HIV infection was 10.2% (7.5%-13.5%) with the CDC-modified Bio-Rad-Avidity assay as compared to 6.0% (3.9%-8.7%) with the Sedia-LAg-Avidity assay. When optimizing a multiassay algorithm (MAA) that includes sequentially the CDC-modified Bio-Rad-Avidity assay then the Sedia-LAg-Avidity assay EIA (avidity index/ODn: 30%/1.7), the MDRI was 136 days (95% CI 123-148) and the FRR, 3.3% (95% CI 1.8-5.6). CONCLUSION: Multiassay algorithms that include the CDC-modified Bio-Rad-Avidity assay and the Sedia-LAg-Avidity assay performed better than each avidity assay alone. Such 2-assay algorithm that starts with the CDC-modified Bio-Rad-Avidity assay followed by the Sedia-LAg-Avidity assay allowed a better classification of HIV-1 infections.

Family physicians' intention to support women in making informed decisions about breast cancer screening with mammography: a cross-sectional survey.

BACKGROUND: The net benefits of routine breast cancer screening with mammography have been questioned, and there is evidence to indicate that supporting women to make an informed decision about breast cancer screening with mammography is preferable. The aims of this study were to assess the intention of family physicians to provide women with this support and the determinants of this intention, and to identify factors that might influence family physicians adopting this behavior. METHODS: Family physicians from the province of Quebec, Canada, attending a 45-min lecture on informed decision making and cancer screening were asked to complete a questionnaire after the lecture regarding their intention to adopt the behavior. The questions, based on the Theory of Planned Behavior, measured physicians' intention and its determinants (attitude, perceived behavioral control, and socio-professional norm) regarding supporting women to make informed decisions about breast cancer screening with mammography. Open-ended questions were also used to explore complementary factors influencing their intention. RESULTS: Out of 800 questionnaires distributed, 301 (38 %) were returned and 288 were included in data analysis. The mean ± standard deviation and median score for intention were respectively 1.9 ± 1.2 and 2.0 on a 6-point Likert scale (-3 to +3). Perceived behavioral control was the variable most strongly associated with intention (high versus low score, odds ratio = 15.7, 95 % CI 6.7-36.6), followed by attitude (high versus low score, odds ratio = 7.5, 95 % CI 3.3-16.8), then social norm (high versus low score, odds ratio = 5.8, 95 % CI 2.6-12.9). The most-reported barrier to adopting the behavior was time constraints (41 %) while the most-reported facilitator was availability of relevant decision support tools (29 %). CONCLUSIONS: Respondents showed strong intention to support women in informed decision-making about breast cancer screening, the strongest predictor being perceived behavioral control. These results could contribute to training physicians to integrate this behavior into their practices and to designing relevant decision support tools.

Carbapenem non-susceptible enterobacteriaceae in Quebec, Canada: results of a laboratory surveillance program (2010-2012).

The emergence and spread of carbapenemase-producing Enterobacteriaceae (CPE) represent a major public health concern because these bacteria are usually extensively resistant to most antibiotics. In order to evaluate their dissemination in Quebec, a surveillance program was introduced in 2010. We report the molecular and epidemiological profiles of CPE isolates collected. Between August 2010 and December 2012, a total of 742 non-duplicate isolates non-susceptible to carbapenems were analysed. AmpC ß-lactamase and metallo-ß-lactamase production were detected by Etest and carbapenemase production by the modified Hodge test (MHT). Antibiotic susceptibility profiles were determined using broth microdilution or Etest. Clonality of Klebsiella pneumoniae carbapenemase (KPC) strains was analyzed by pulsed-field gel electrophoresis (PFGE). The presence of genes encoding carbapenemases as well as other ß-lactamases was detected using PCR. Of the 742 isolates tested, 169 (22.8%) were CPE. Of these 169 isolates, 151 (89.3%) harboured a blaKPC gene while the remaining isolates carried blaSME (n = 9), blaOXA-48 (n = 5), blaNDM (n = 3), and blaNMC (n = 1) genes. Among the 93 KPC strains presenting with a unique pattern (unique PFGE pattern and/or unique antibiotics susceptibility profile), 99% were resistant to ertapenem, 95% to imipenem, 87% to meropenem, 97% to aztreonam, 31% to colistin and 2% to tigecycline. In 19 patients, 2 to 5 KPC strains from different species or with a different PFGE pattern were isolated. CPE strains were present in the province of Quebec with the majority of strains harbouring KPC. Alternately, SME, OXA-48 and NMC containing strains were rarely found.