Molecular Analysis of Antimicrobial Resistance Mechanisms in Neisseria gonorrhoeae Isolates from Ontario, Canada▿

Surveillance of gonococcal antimicrobial resistance and the molecular characterization of the mechanisms underlying these resistance phenotypes are essential in order to establish correct empirical therapies, as well as to describe the emergence of new mechanisms in local bacterial populations. To address these goals, 149 isolates were collected over a 1-month period (October-November 2008) at the Ontario Public Health Laboratory, Toronto, Canada, and susceptibility profiles (8 antibiotics) were examined. Mutations in previously identified targets or the presence of some enzymes related to resistance (r), nonsusceptibility (ns) (resistant plus intermediate categories), or reduced susceptibility (rs) to the antibiotics tested were also studied. A significant proportion of nonsusceptibility to penicillin (PEN) (89.2%), tetracycline (TET) (72.3%), ciprofloxacin (CIP) (29%), and macrolides (erythromycin [ERY] and azithromycin; 22.3%) was found in these strains. Multidrug resistance was observed in 18.8% of the collection. Although all the strains were susceptible to spectinomycin and extended-spectrum cephalosporins (ESC) (ceftriaxone and cefixime), 9.4% of them displayed reduced susceptibility to extended-spectrum cephalosporins. PBP 2 mosaic structures were found in all of these ESCrs isolates. Alterations in the mtrR promoter, MtrR repressor (TETr, PENns, ESCrs, and ERYns), porin PIB (TETr and PENns), and ribosomal protein S10 (TETr) and double mutations in gyrA and parC quinolone resistance-determining regions (QRDRs) (CIPr) were associated with and presumably responsible for the resistance phenotypes observed. This is the first description of ESCrs in Canada. The detection of this phenotype indicates a change in the epidemiology of this resistance and highlights the importance of continued surveillance to preserve the last antimicrobial options available

The epidemiology of sexually transmitted co-infections in HIV-positive and HIV-negative African-Caribbean women in Toronto

Abstract Background HIV disproportionately affects African-Caribbean women in Canada but the frequency and distribution of sexually transmitted infections in this community have not been previously studied. Methods We recruited women based on HIV status through a Toronto community health centre. Participants completed a socio-behavioural questionnaire using Audio Computer Assisted Self-Interview (ACASI) and provided blood for syphilis, HIV, hepatitis B and C, herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), and human cytomegalovirus (CMV) serology, urine for chlamydia and gonorrhea molecular testing and vaginal secretions for bacterial vaginosis (BV) and human papillomavirus (HPV). Differences in prevalence were assessed for statistical significance using chi-square. Results We recruited 126 HIV-positive and 291 HIV-negative women, with a median age of 40 and 31 years, respectively (p < 0.001). Active HBV infection and lifetime exposure to HBV infection were more common in HIV-positive women (4.8% vs. 0.34%, p = 0.004; and 47.6% vs. 21.2%, p < 0.0001), as was a self-reported history of HBV vaccination (66.1% vs. 44.0%, p = 0.0001). Classical STIs were rare in both groups; BV prevalence was low and did not vary by HIV status. HSV-2 infection was markedly more frequent in HIV-positive (86.3%) than HIV-negative (46.6%) women (p < 0.0001). Vaginal HPV infection was also more common in HIV-positive than in HIV-negative women (50.8% vs. 22.6%, p < 0.0001) as was infection with high-risk oncogenic HPV types (48.4% vs. 17.3%, p < 0.0001). Conclusions Classical STIs were infrequent in this clinic-based population of African-Caribbean women in Toronto. However, HSV-2 prevalence was higher than that reported in previous studies in the general Canadian population and was strongly associated with HIV infection, as was infection with hepatitis B and HPV

The glucocorticoid response in a free-living bird predicts whether long-lasting memories fade or strengthen with time

For decades, scientists have used threat conditioning (traditionally termed ‘fear conditioning’) to study the link between glucocorticoids and the consolidation of long-term memories (i.e. memories that last hours to weeks) in model organisms in the laboratory. We assessed this relationship in a free-living species, and examined a possible relationship between glucocorticoids and the retention of long-lasting memories (i.e. memories that last months to a lifetime). We developed a novel threat-conditioning protocol by which free-living Florida scrub-jays, Aphelocoma coerulescens, were either chased by a novel predator or exposed to a control. We measured flight initiation distance (FID) 48 h, 11 months and 2 years after conditioning or control exposures, and compared these measures to levels of stress-induced glucocorticoids. Conditioned subjects maintained significantly longer FIDs for at least 2 years. Furthermore, the long-term memory consolidation of conditioned subjects positively correlated with their stress-induced glucocorticoid response, similar to results from laboratory studies. Surprisingly, individuals with a moderate stress response exhibited an exaggerated defence response (i.e. FIDs increased) at 11 months and 2 years post-conditioning, whereas low and high stress responders exhibited memory decay or extinction (i.e. FIDs decreased). We speculate that the recently discovered processes of memory reconsolidation and system consolidation may help explain why some Florida scrub-jays exhibit more fearful-like behaviour with time