N. Rau - Academia.edu (original) (raw)
Papers by N. Rau
CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, Jan 27, 2003
In August and September 2002 an outbreak of West Nile virus (WNV) infection occurred in southern ... more In August and September 2002 an outbreak of West Nile virus (WNV) infection occurred in southern Ontario. We encountered a number of seriously ill patients at our hospitals. In this article we document the clinical characteristics of these cases. We conducted a retrospective chart review of patients who came to the attention of infectious disease or neurology consultants or the microbiology laboratories at 7 hospitals in the municipalities of Toronto, Peel and Halton, Ont. Patients were included if they had been admitted to hospital or stayed overnight in the emergency department, had serological evidence of WNV infection and had clinical evidence of WNV fever, aseptic meningitis, encephalomyelitis or motor neuronopathy. In all, 64 patients met the inclusion criteria; 57 had encephalitis or neuromuscular weakness or both, 5 had aseptic meningitis, and 2 had WNV fever. The mean age was 61 years (range 26-87). The patients were predominantly active, middle-aged or elderly people livin...
Clinical Infectious Diseases, 2014
Estimating the risk of antibiotic resistance is important in selecting empiric antibiotics. We as... more Estimating the risk of antibiotic resistance is important in selecting empiric antibiotics. We asked how the timing, number of courses, and duration of antibiotic therapy in the previous 3 months affected antibiotic resistance in isolates causing invasive pneumococcal disease (IPD). We conducted prospective surveillance for IPD in Toronto, Canada, from 2002 to 2011. Antimicrobial susceptibility was measured by broth microdilution. Clinical information, including prior antibiotic use, was collected by chart review and interview with patients and prescribers. Clinical information and antimicrobial susceptibility were available for 4062 (90%) episodes; 1193 (29%) of episodes were associated with receipt of 1782 antibiotic courses in the prior 3 months. Selection for antibiotic resistance was class specific. Time elapsed since most recent antibiotic was inversely associated with resistance (cephalosporins: adjusted odds ratio [OR] per day, 0.98; 95% confidence interval [CI], .96-1.00; P = .02; macrolides: OR, 0.98; 95% CI, .96-.99; P = .005; penicillins: OR [log(days)], 0.62; 95% CI, .44-.89; P = .009; fluoroquinolones: profile penalized-likelihood OR [log(days)], 0.62; 95% CI, .39-1.04; P = .07). Risk of resistance after exposure declined most rapidly for fluoroquinolones and penicillins and reached baseline in 2-3 months. The decline in resistance was slowest for macrolides, and in particular for azithromycin. There was no significant association between duration of therapy and resistance for any antibiotic class. Too few patients received multiple courses of the same antibiotic class to assess the significance of repeat courses. Time elapsed since last exposure to a class of antibiotics is the most important factor predicting antimicrobial resistance in pneumococci. The duration of effect is longer for macrolides than other classes.
European Journal of Clinical Microbiology & Infectious Diseases, 1999
Decision analysis methods were used to compare four mycobacteriology laboratory strategies with r... more Decision analysis methods were used to compare four mycobacteriology laboratory strategies with respect to time to confirmation and exclusion of smear-positive and smear-negative cases of pulmonary tuberculosis. Strategies assessed included the following: (i) polymerase chain reaction (PCR) on all respiratory specimens; (ii) PCR on smear-positive specimens and on the broth of vials for other specimens attaining a growth index >10 in a radiometric culture detection system; (iii) PCR on smear-positive specimens only; and (iv) radiometric culture detection, with DNA probe for species identification of vials attaining a growth index >999. Strategies i and ii had predicted average times to confirm cases of 5 and 7.6 days, respectively, and remained within 3 days of each other over a broad range of PCR performance with smear-negative specimens. In contrast, case-confirmation times using strategies iii and iv were 10.4 and 15.3 days, respectively. Only 10% of specimens were processed by PCR in strategy ii. Times to confirm smear-negative cases were comparable for strategies i and ii when PCR sensitivity was <40% with these specimens. Times to exclude pulmonary tuberculosis were similar for all strategies. Given the current suboptimal performance of PCR with smear-negative specimens, strategy ii offers accelerated case confirmation with limited PCR usage.
CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, Jan 27, 2003
In August and September 2002 an outbreak of West Nile virus (WNV) infection occurred in southern ... more In August and September 2002 an outbreak of West Nile virus (WNV) infection occurred in southern Ontario. We encountered a number of seriously ill patients at our hospitals. In this article we document the clinical characteristics of these cases. We conducted a retrospective chart review of patients who came to the attention of infectious disease or neurology consultants or the microbiology laboratories at 7 hospitals in the municipalities of Toronto, Peel and Halton, Ont. Patients were included if they had been admitted to hospital or stayed overnight in the emergency department, had serological evidence of WNV infection and had clinical evidence of WNV fever, aseptic meningitis, encephalomyelitis or motor neuronopathy. In all, 64 patients met the inclusion criteria; 57 had encephalitis or neuromuscular weakness or both, 5 had aseptic meningitis, and 2 had WNV fever. The mean age was 61 years (range 26-87). The patients were predominantly active, middle-aged or elderly people livin...
Clinical Infectious Diseases, 2014
Estimating the risk of antibiotic resistance is important in selecting empiric antibiotics. We as... more Estimating the risk of antibiotic resistance is important in selecting empiric antibiotics. We asked how the timing, number of courses, and duration of antibiotic therapy in the previous 3 months affected antibiotic resistance in isolates causing invasive pneumococcal disease (IPD). We conducted prospective surveillance for IPD in Toronto, Canada, from 2002 to 2011. Antimicrobial susceptibility was measured by broth microdilution. Clinical information, including prior antibiotic use, was collected by chart review and interview with patients and prescribers. Clinical information and antimicrobial susceptibility were available for 4062 (90%) episodes; 1193 (29%) of episodes were associated with receipt of 1782 antibiotic courses in the prior 3 months. Selection for antibiotic resistance was class specific. Time elapsed since most recent antibiotic was inversely associated with resistance (cephalosporins: adjusted odds ratio [OR] per day, 0.98; 95% confidence interval [CI], .96-1.00; P = .02; macrolides: OR, 0.98; 95% CI, .96-.99; P = .005; penicillins: OR [log(days)], 0.62; 95% CI, .44-.89; P = .009; fluoroquinolones: profile penalized-likelihood OR [log(days)], 0.62; 95% CI, .39-1.04; P = .07). Risk of resistance after exposure declined most rapidly for fluoroquinolones and penicillins and reached baseline in 2-3 months. The decline in resistance was slowest for macrolides, and in particular for azithromycin. There was no significant association between duration of therapy and resistance for any antibiotic class. Too few patients received multiple courses of the same antibiotic class to assess the significance of repeat courses. Time elapsed since last exposure to a class of antibiotics is the most important factor predicting antimicrobial resistance in pneumococci. The duration of effect is longer for macrolides than other classes.
European Journal of Clinical Microbiology & Infectious Diseases, 1999
Decision analysis methods were used to compare four mycobacteriology laboratory strategies with r... more Decision analysis methods were used to compare four mycobacteriology laboratory strategies with respect to time to confirmation and exclusion of smear-positive and smear-negative cases of pulmonary tuberculosis. Strategies assessed included the following: (i) polymerase chain reaction (PCR) on all respiratory specimens; (ii) PCR on smear-positive specimens and on the broth of vials for other specimens attaining a growth index >10 in a radiometric culture detection system; (iii) PCR on smear-positive specimens only; and (iv) radiometric culture detection, with DNA probe for species identification of vials attaining a growth index >999. Strategies i and ii had predicted average times to confirm cases of 5 and 7.6 days, respectively, and remained within 3 days of each other over a broad range of PCR performance with smear-negative specimens. In contrast, case-confirmation times using strategies iii and iv were 10.4 and 15.3 days, respectively. Only 10% of specimens were processed by PCR in strategy ii. Times to confirm smear-negative cases were comparable for strategies i and ii when PCR sensitivity was <40% with these specimens. Times to exclude pulmonary tuberculosis were similar for all strategies. Given the current suboptimal performance of PCR with smear-negative specimens, strategy ii offers accelerated case confirmation with limited PCR usage.