Molecular surveillance of hepatitis C virus genotypes identifies the emergence of a genotype 4d lineage among men in Quebec, 2001-2017.

BACKGROUND: Molecular phylogenetics are generally used to confirm hepatitis C virus (HCV) transmission events. In addition, the Laboratoire de santé publique du Québec (LSPQ) has been using molecular phylogenetics for surveillance of HCV genotyping since November 2001. OBJECTIVES: To describe the emergence of a specific lineage of HCV genotype 4d (G4d) and its characteristics using molecular phylogenetics as a surveillance tool for identifying HCV strain clustering. METHODS: The LSPQ prospectively applied Sanger sequencing and phylogenetic analysis to determine the HCV genotype on samples collected from November 2001 to December 2017. When a major G4d cluster was identified, demographic information, HIV-infection status and syphilis test results were analyzed. RESULTS: Phylogenetic analyses performed on approximately 22,000 cases identified 122 G4d cases. One major G4d cluster composed of 37 cases was singled out. Two cases were identified in 2010, 10 from 2011-2014 and 25 from 2015-2017. Cases in the cluster were concentrated in two urban health regions. Compared to the other G4d cases, cluster cases were all male (p<0.001) and more likely to be HIV-positive (adjusted risk ratio: 4.4; 95% confidence interval: 2.5-7.9). A positive syphilis test result was observed for 27 (73%) of the cluster cases. The sequences in this cluster and of four outlier cases were located on the same monophyletic lineage as G4d sequences reported in HIV-positive men who have sex with men (MSM) in Europe. CONCLUSION: Molecular phylogenetics enabled the identification and surveillance of ongoing transmission of a specific HCV G4d lineage in HIV-positive and HIV-negative men in Quebec and its cross-continental spread. This information can orient intervention strategies to avoid transmission of HCV in MSM.

Canadian recommendations for laboratory interpretation of multiple or extensive drug resistance in clinical isolates of Enterobacteriaceae, Acinetobacter species and Pseudomonas aeruginosa.

The goal of this document was to provide Canadian laboratories with a framework for consistent reporting and monitoring of multidrug resistant organisms (MDRO) and extensively drug resistant organisms (XDRO) for common gram-negative pathogens. This is the final edition of the interim recommendations, which were modified after one year of broad consultative review. This edition represents a consensus of peer-reviewed information and was co-authored by the Canadian Public Health Laboratory Network and the Canadian Association of Clinical Microbiology and Infectious Diseases. There are two main recommendations. The first recommendation provides standardized definitions for MDRO and XDRO for gram-negative organisms in clinical specimens. These definitions were limited to antibiotics that are commonly tested clinically and, to reduce ambiguity, resistance (rather than non-susceptibility) was used to calculate drug resistance status. The second recommendation identifies the use of standardized laboratory reporting of organisms identified as MDRO or XDRO. Through the broad consultation, which included public health and infection prevention and control colleagues, these definitions are ready to be applied for policy development. Both authoring organizations intend to review these recommendations regularly as antibiotic resistance testing evolves in Canada.

Lymphogranuloma venereum in Quebec: Re-emergence among men who have sex with men.

BACKGROUND: Lymphogranuloma venereum (LGV) is a sexually transmitted infection (STI) caused by Chlamydia trachomatis genotypes L1, L2 and L3. This LGV is associated with significant morbidity and increased risk of HIV transmission. While fewer than two cases per year were reported in Quebec before 2005, LGV emerged in 2005-2006 with 69 cases, followed by a period of low incidence (2007-2012), and subsequent re-emergence since 2013. OBJECTIVES: To describe the incidence of LGV in Quebec and the characteristics of the affected population, including demographics and risk factors, clinical manifestations, laboratory tests, treatments and reinfection rates. METHODS: Descriptive data were collected from the notifiable diseases records through the Institut national de santé publique du Québec (INSPQ) infocentre portal. Questionnaires were obtained through the enhanced surveillance system and transmitted anonymously to the Quebec Ministry of Health. In-depth analysis was performed on cases from 2013 to 2016. RESULTS: There were 338 cases of LGV over the four-year period in Quebec. All cases were male, excluding one transsexual. Mean age was 41 years. Most lived in Montréal (81%) and were men who have sex with men (MSM; 99%). The majority (83%) reported four sexual partners or more in the last year, met mostly through the Internet (77%) and in saunas (73%). Frequency of sexual intercourse with out-of-province residents decreased in 2013-2016 (27%) compared with 2005-2012 (38%). History of STIs was frequent: 83% were HIV-infected, 81% reported previous syphilis and 78% previous gonorrhea. Recreational drug use was frequent (57%), reaching 71% in 2016. Most cases were symptomatic, a proportion which decreased in 2016 (68%) compared with 2013-2015 (82%; p=0.006). Clinical presentations included proctitis (86%), lymphadenopathy (13%) and ulcer/papule (12%). Reinfections, mostly within two years of first infection, occurred in 35 individuals (10%).Conclusion: The re-emergence of LGV in Quebec involves an urban subpopulation composed almost exclusively of MSM with STIs, who have a high number of partners and often use drugs.

Trends in the use of laboratory tests for the diagnosis of Clostridium difficile infection and association with incidence rates in Quebec, Canada, 2010-2014.

BACKGROUND: Several Clostridium difficile infection (CDI) surveillance programs do not specify laboratory strategies to use. We investigated the evolution in testing strategies used across Quebec, Canada, and its association with incidence rates. METHODS: Cross-sectional study of 95 hospitals by surveys conducted in 2010 and in 2013-2014. The association between testing strategies and institutional CDI incidence rates was analyzed via multivariate Poisson regressions. RESULTS: The most common assays in 2014 were toxin A/B enzyme immunoassays (EIAs) (61 institutions, 64%), glutamate dehydrogenase (GDH) EIAs (51 institutions, 53.7%), and nucleic acid amplification tests (NAATs) (34 institutions, 35.8%). The most frequent algorithm was a single-step NAAT (20 institutions, 21%). Between 2010 and 2014, 35 institutions (37%) modified their algorithm. Institutions detecting toxigenic C difficile instead of C difficile toxin increased from 14 to 37 (P < .001). Institutions detecting toxigenic C difficile had higher CDI rates (7.9 vs 6.6 per 10,000 patient days; P = .01). Institutions using single-step NAATs, GDH plus toxigenic cultures, and GDH plus cytotoxicity assays had higher CDI rates than those using an EIA-based algorithm (P < .05). CONCLUSIONS: Laboratory detection of CDI has changed since 2010. There is an association between diagnostic algorithms and CDI incidence. Mitigation strategies are warranted.

[Antibiotic consumption and bacterial sensitivity in a teaching hospital: A 5-year study]. / Profil de consommation et de sensibilité aux antibiotiques utilisés dans un centre hospitalier universitaire : étude rétrospective sur cinq ans.

INTRODUCTION: To reduce risks of antibiotic resistance, governmental and learned societies decreed the optimal use of antibiotics. The relation between antibiotic consumption and bacterial resistance increase has been clearly demonstrated over the last several years. Antibiotic consumption data and bacterial sensitivity data are regularly published, but very few publications have searched for a correlation between these two variables. This study focused on antibiotic use and consumption as well as bacterial sensitivity to these antibiotics. OBJECTIVES: The main objective was to describe the changes in antibiotic consumption and bacterial sensitivity in a mother-child teaching hospital. The secondary objectives were to explore whether antibiotic use and bacterial sensitivity were correlated and to comment on the usefulness of these data for clinicians. METHODS: This was a 5-year retrospective, descriptive, cross-sectional study. All samples from usually sterile biologic liquids of hospitalized pediatric patients were included in the study. The samples from outpatient clinics were excluded. All types of bacteria identified in more than 30 isolates were included in the study. The antibiotics usually used to treat these bacteria were included. To assess antibiotic consumption, we calculated the number of days of therapy per 1000 patient-days for hospitalized pediatric patients and we calculated the Pearson correlation coefficient between antibiotic consumption and sensitivity rates to these antibiotics. Two scenarios were explored: one with correlation by year and one with the next year for bacterial sensitivity. RESULTS: During the study period (2010-2011 to 2014-2015), overall antibiotics consumption remained relatively stable. Concerning bacterial sensitivity, we noted important changes (sensitivity rates increased for 12 antibiotic-bacteria pairs, remained stable for five, and decreased for 15). We found three significant correlations for the first scenario: Pseudomonas aeruginos-ceftazidime (P=0.01), P. aeruginosa-ciprofloxacin and fluoroquinolone consumption (P=0.02), Enterococcus sp-ampicillin and penicillin consumption (P=0.04). For the second scenario, we found only two significant correlations: coagulase-negative Staphylococcus-oxacilline and penicillin consumption (P=0.02), P. aeruginosa/piperacillin (P=0.04). CONCLUSION: This exploratory study allowed us to describe antibiotic consumption and bacterial sensitivity progression. To our knowledge, this is the first study exploring the correlation between antibiotic consumption and the bacterial sensitivity rate in pediatrics in Canada. It remains very difficult to show this correlation between these two variables because of the multiple sources of bacterial resistance. These data are particularly useful for the antimicrobial stewardship programs and for clinicians.

Modeling optical breakdown in dielectrics during ultrafast laser processing.

Laser ablation is widely used in micromachining, manufacturing, thin-film formation, and bioengineering applications. During laser ablation the removal of material and quality of the features depend strongly on the optical breakdown region induced by the laser irradiance. The recent advent of amplified ultrafast lasers with pulse durations of less than 1 ps has generated considerable interest because of the ability of the lasers to process virtually all materials with high precision and minimal thermal damage. With ultrashort pulse widths, however, traditional breakdown models no longer accurately capture the laser-material interaction that leads to breakdown. A femtosecond breakdown model for dielectric solids and liquids is presented that characterizes the pulse behavior and predicts the time- and position-dependent breakdown region. The model includes the pulse propagation and small spatial extent of ultrashort laser pulses. Model results are presented and compared with classical breakdown models for 1-ns, 1-ps, and 150-fs pulses. The results show that the revised model is able to model breakdown accurately in the focal region for pulse durations of less than 10 ps. The model can also be of use in estimating the time- and position-resolved electron density in the interaction volume, the breakdown threshold of the material, shielding effects, and temperature distributions during ultrafast processing.

Calculation of mean cell residence time for unsteady-state activated sludge systems.

A formulation to calculate the mean cell residence time (MCRT or sludge age) of unsteady-state activated sludge systems is presented. The formulation was studied by applying it to data generated by computer simulation and to data obtained from an actual wastewater treatment plant. The computer simulation study allowed the effects of step and pulse changes in biochemical oxygen demand (BOD) loading, and step changes in a control variable, waste sludge flow rate, to be studied independently of each other and of other disturbances. The unsteady-state MCRT formulation (herein called the dynamic sludge age, or DSA) was found to be an improvement over the traditional steady-state calculation, both for process control, and for research into activated sludge dynamics.

"Cytogenetic" studies of spermatids of mice carrying Cattanach's translocation by flow cytometry.

The DNA content of spermatids of mice carrying Cattanach's translocation has been measured with high precision by flow cytometry. The observation that the two peaks of DNA content in the haploid region of the DNA histograms represent X- and Y-bearing spermatids was tested and confirmed. Using flow cytometry, the difference in DNA content between the X and Y chromosomes in these mice was measured to be 5.2 +/- 0.1% of the total haploid genome as compared to 3.4 +/- 0.1% in normal mice. These results demonstrated the precision of flow cytometry for cytogenetic studies. Additional information on spermatogenesis in mice bearing Cattanach's translocation was obtained and showed a gradual loss of cells during spermatogenesis in those bearing the balanced form of the translocation.