Showing papers by "Tom Wong published in 2016"
TL;DR: Geographic and temporal phylogenetic clustering indicates that emergent AZMr strains arise independently and can then rapidly expand clonally in a region through local sexual networks.
Abstract: The emergence of Neisseria gonorrhoeae strains with decreased susceptibility to cephalosporins and azithromycin (AZM) resistance (AZM(r)) represents a public health threat of untreatable gonorrhea infections. Genomic epidemiology through whole-genome sequencing was used to describe the emergence, dissemination, and spread of AZM(r) strains. The genomes of 213 AZM(r) and 23 AZM-susceptible N. gonorrhoeae isolates collected in Canada from 1989 to 2014 were sequenced. Core single nucleotide polymorphism (SNP) phylogenomic analysis resolved 246 isolates into 13 lineages. High-level AZM(r) (MICs ≥ 256 μg/ml) was found in 5 phylogenetically diverse isolates, all of which possessed the A2059G mutation (Escherichia coli numbering) in all four 23S rRNA alleles. One isolate with high-level AZM(r) collected in 2009 concurrently had decreased susceptibility to ceftriaxone (MIC = 0.125 μg/ml). An increase in the number of 23S rRNA alleles with the C2611T mutations (E. coli numbering) conferred low to moderate levels of AZM(r) (MICs = 2 to 4 and 8 to 32 μg/ml, respectively). Low-level AZM(r) was also associated with mtrR promoter mutations, including the -35A deletion and the presence of Neisseria meningitidis-like sequences. Geographic and temporal phylogenetic clustering indicates that emergent AZM(r) strains arise independently and can then rapidly expand clonally in a region through local sexual networks.
126 citations
TL;DR: The proportion of isolates with decreased susceptibility to cephalosporins declined significantly between 2011 and 2014, whereas azithromycin resistance increased significantly during that period, indicating continued surveillance of antimicrobial drug susceptibilities is imperative to inform treatment guidelines.
Abstract: Gonorrhea, caused by Neisseria gonorrhoeae, is the second most commonly reported sexually transmitted infection in Canada; ≈13,000 cases occur yearly, and rates have increased from 20.1 cases/100,000 population in 2000 to 39.2 cases/100,000 in 2013 (1). The infection is also a global public health threat, with ≈106 million cases/year occurring worldwide (2). Gonococci have acquired resistance to many antimicrobial agents used for treatment (3), however, which makes it imperative to conduct surveillance programs so appropriate treatment recommendations can be determined. In 2011, the increases in MICs of cephalosporins prompted the authors of the Canadian Sexually Transmitted Infections Guidelines to update the recommended gonorrhea treatment from a single antimicrobial drug to combination therapy with ceftriaxone (250 mg intramuscularly) and azithromycin (1 g orally in a single dose) as the first-line treatment for uncomplicated anogenital and pharyngeal N. gonorrhoeae infections in adults (4). We analyzed antimicrobial drug susceptibility levels of N. gonorrhoeae to cephalosporins and azithromycin in Canada since the recommended treatments were updated in 2011.
46 citations
TL;DR: If cervical cancer screening uptake would increase among under-screened women living in rural Ontario, Canada, if at-home self-collected sampling for human papillomavirus (HPV) testing was offered as a primary cervical cancerScreening modality, compared to invited papanicolaou (Pap) testing or routine opportunistic screening.
Abstract: Background: Our aim was to determine if cervical cancer screening uptake would increase among under-screened women living in rural Ontario, Canada, if at-home self-collected sampling for human papillomavirus (HPV) testing was offered as a primary cervical cancer screening modality, compared to invited papanicolaou (Pap) testing or routine opportunistic screening. Methods: Women 30–70 years of age who were overdue for cervical cancer screening were randomized to receive (1) an at-home self-collected HPV kit, (2) a reminder invitation for Pap testing, or (3) standard of care opportunistic screening. The first two arms were also asked demographic and screening history questions. Women randomized to arm 1 were asked about acceptability. Results: In total, 818 eligible women were identified in a small rural community in Southwestern Ontario: 335 received a self-collected HPV testing kit, 331 received a reminder letter, and 152 received standard of care. In the HPV self-collection arm, 21% (70/335) ret...
34 citations