Background In our population, the most common serotype (ST) of S. pneumoniae causing invasive pneumococcal disease (IPD) is now ST 3. We undertook an analysis of population based surveillance for IPD to examine the incidence and... more
Background In our population, the most common serotype (ST) of S. pneumoniae causing invasive pneumococcal disease (IPD) is now ST 3. We undertook an analysis of population based surveillance for IPD to examine the incidence and epidemiology of ST 3 disease over the last 25 years. Methods The Toronto Invasive Bacterial Diseases Network has performed population-based surveillance for IPD in Toronto/Peel region (pop’n 4.5M) since 1995. All sterile site isolates of S. pneumoniae are reported to a central study laboratory, isolates are serotyped, and clinical and vaccination data are collected via patient and physician interview and chart review. Population data are obtained from Statistics Canada. Results From 1995-2020, 11032 episodes of IPD occurred; 10015 had STs available, and 10484 clinical data. Overall, ST 3 comprised 9.2% of cases (N=931). Compared to other patients with IPD, those with ST 3 IPD were older (median age 65 vs. 58.5, P< .001), more likely to have underlying lun...
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Additional file 1: Appendix S1. Junior Rounds 2015â 2016 survey questions.
OBJECTIVE To review insights gained from a 21-year experience with gentamicin-induced vestibulotoxicity including differences in vestibulotoxicity between single daily dosing (SDD) and multiple daily dosing (MDD) regimens. STUDY DESIGN... more
OBJECTIVE To review insights gained from a 21-year experience with gentamicin-induced vestibulotoxicity including differences in vestibulotoxicity between single daily dosing (SDD) and multiple daily dosing (MDD) regimens. STUDY DESIGN Retrospective case series. SETTING Tertiary care center. PATIENTS Patients with gentamicin vestibulotoxicity referred to the Hertz Multidisciplinary Neurotology Clinic between January 1993 and September 2014. INTERVENTION None. MAIN OUTCOME MEASURES Spectrum of vestibular dysfunction measured using videonystagmography, vestibular evoked myogenic potentials, video head impulse testing, and magnetic scleral search coil testing. RESULTS Of 53 patients with gentamicin-induced vestibulotoxicity, 24 received SDD and 29 received MDD treatment. The most common indications for treatment were sepsis, endocarditis, and osteomyelitis. Angular acceleration receptor function (semicircular canals) was more commonly affected than linear acceleration receptor function (otolithic organ of the saccule; 100% vs. 62%). A significant proportion of patients (53%) developed vestibulotoxicity in the absence of nephrotoxicity and 40% experienced vestibulotoxicity in a delayed fashion up to 10 days posttreatment cessation (mean 3.9 ± 0.7). Therapeutic monitoring did not necessarily prevent delayed vestibulotoxicity. Nephrotoxicity was less common for SDD compared with MDD (60% vs. 35%, p = 0.01). However, the SDD group experienced vestibulotoxicity at a lower cumulative dose (6.3 vs. 7.0 g, p = 0.04) and shorter duration of therapy (20.7 vs 29.4 d, p = 0.02). CONCLUSIONS Our study further highlights important insights regarding gentamicin-induced vestibulotoxicity. While SDD is associated with decreased risk for nephrotoxicity compared with MDD, it confers a higher risk for vestibulotoxicity.
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Surveillance data from Southern Ontario show that a majority of Verona Integron-encoded Metallo-β-lactamase (VIM)-producingEnterobacteriaceaeare locally acquired. To better understand the local epidemiology, we analysed clinical and... more
Surveillance data from Southern Ontario show that a majority of Verona Integron-encoded Metallo-β-lactamase (VIM)-producingEnterobacteriaceaeare locally acquired. To better understand the local epidemiology, we analysed clinical and environmentalblaVIM-positiveEnterobacteriaceaefrom the area. Clinical samples were collected within the Toronto Invasive Bacterial Diseases Network (2010–2016); environmental water samples were collected in 2015. We gathered patient information on place of residence and hospital admissions prior to the diagnosis. Patients with and without plausible source of acquisition were compared regarding risk exposures. Microbiological isolates underwent whole-genome sequencing (WGS);blaVIMcarrying plasmids were characterized. We identified 15 patients, thereof 11 withblaVIM-1-positiveEnterobacter hormaecheiwithin two genetic clusters based on WGS. Whereas no obvious epidemiologic link was identified among cluster I patients, those in cluster II were connected to a...
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Background The burden of Clostridium difficile infection (CDI) has increased in the last decade, with more adverse outcomes and related mortality. Although many predictive scores were developed, few were validated and their performances... more
Background The burden of Clostridium difficile infection (CDI) has increased in the last decade, with more adverse outcomes and related mortality. Although many predictive scores were developed, few were validated and their performances were sub-optimal. We conducted an external validation study of predictive scores or models for mortality in CDI. Methods Published predictive tools were identified through a systematic review. We included those reporting at least an internal validation approach. A multicenter prospective cohort of 1380 adults with confirmed CDI enrolled in two Canadian provinces was used for external validation. Most cases were elderly (median age 71), had a healthcare facility-associated CDI (90%), and 52% were infected by NAP1/BI/027 strains. All-cause 30-day death occurred in 12% of patients. The performance of each scoring system was analyzed using individual primary outcomes. Results We identified two scores which performances (95% CI) are shown in the table. Bo...
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We enrolled 91 consecutive inpatients with COVID-19 at 6 hospitals in Toronto, Canada, and tested 1 nasopharyngeal swab/saliva sample pair from each patient using real-time RT-PCR for severe acute respiratory syndrome coronavirus 2.... more
We enrolled 91 consecutive inpatients with COVID-19 at 6 hospitals in Toronto, Canada, and tested 1 nasopharyngeal swab/saliva sample pair from each patient using real-time RT-PCR for severe acute respiratory syndrome coronavirus 2. Sensitivity was 89% for nasopharyngeal swabs and 72% for saliva (P = .02). Difference in sensitivity was greatest for sample pairs collected later in illness.
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Background Clostridium difficile infection (CDI) is the most common cause of nosocomial diarrhea. About one in 5 patients with CDI (median 18%) develop a complication (cCDI), including mortality. Many predictive scores have been published... more
Background Clostridium difficile infection (CDI) is the most common cause of nosocomial diarrhea. About one in 5 patients with CDI (median 18%) develop a complication (cCDI), including mortality. Many predictive scores have been published to identify patients at risk of cCDI but none is currently recommended for clinical use and few were validated. We conducted an external validation study of predictive tools for cCDI. Methods Predictive tools were identified through a systematic review. We included those reporting at least an internal validation process. We performed the external validation on a multicenter prospective cohort of 1380 Canadian adults with confirmed CDI. Most cases were elderly (median age 71), had a healthcare facility-associated CDI (90%), and cCDI occurred in 8%. NAP1 strain was found in 52%. The performance of each scoring system was analyzed using individual outcomes. Modifications in predictors were made to match available data in the validation cohort. Results...
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Background In Ontario, Canada, PCV13 is covered for immunocompromised (IC) adults over 50y. PCV13 programs are thought not to be cost-effective in other adults because it is assumed that herd immunity from pediatric vaccination programs... more
Background In Ontario, Canada, PCV13 is covered for immunocompromised (IC) adults over 50y. PCV13 programs are thought not to be cost-effective in other adults because it is assumed that herd immunity from pediatric vaccination programs (PCV7 since 2005; PCV13 since 2010) will reduce PCV13 disease burden dramatically in adults. We analyzed data from the Toronto Invasive Bacterial Diseases Network (TIBDN) to ask whether PCV13-type invasive pneumococcal disease (IPD) in adults persists in our population. Methods TIBDN performs population-based surveillance for IPD in Toronto+Peel Region, Ontario (pop4.1M). All microbiology laboratories receiving specimens from residents report cases of IPD and submit isolates to a central study lab for serotyping; annual audits are conducted. Demographic, medical and vaccination information are obtained from patients, families and physicians. Population data are from Statistics Canada. Results Since 1995, 10,365 episodes of IPD have been identified; d...
Background. Background Invasive Group A streptococcal (iGAS) infections remain a substantial source of morbidity and mortality. We explore the clinical and molecular epidemiology of iGAS infections in Toronto, Ontario, Canada over a... more
Background. Background Invasive Group A streptococcal (iGAS) infections remain a substantial source of morbidity and mortality. We explore the clinical and molecular epidemiology of iGAS infections in Toronto, Ontario, Canada over a 26-year period. Methods The Toronto Invasive Bacterial Diseases Network has performed population-based surveillance for iGAS infections in metropolitan Toronto and Peel regions since 1992. Participating microbiology laboratories report and submit sterile site specimens for central processing. M typing was performed on iGAS isolates until September 2006; thereafter emm typing was performed. Clinical information was collected by chart review using standardized collection forms. Results Over the 26-year period there were 2819 iGAS infections, representing an average incidence of 2.85 per 100,000 residents with a nadir of 1.65 in 1993 and a peak of 4.52 in 2014. Nosocomial infections occurred in 8.9% (251/2,819). There was substantial variation in annual inc...
At our institution, Morning Report focuses mostly on diagnostic reasoning. This makes it a challenge for first-year residents to learn to manage common on-call emergencies, such as hyperkalemia. We sought to improve their preparedness for... more
At our institution, Morning Report focuses mostly on diagnostic reasoning. This makes it a challenge for first-year residents to learn to manage common on-call emergencies, such as hyperkalemia. We sought to improve their preparedness for the transitions they would encounter: from medical student to physician at the beginning of the academic year, and from junior resident to senior resident toward the end. In response to feedback, we developed the Junior Rounds curriculum: a weekly session focused on the approach to commonly encountered on-call emergencies and internal medicine referrals. Anonymous surveys were sent to trainees, and iterative analysis of monthly feedback led to changes to Junior Rounds. Junior Rounds was implemented from August 2015 to June 2016. Thirty-nine of 92 possible respondents (44%) completed surveys in that period. Most respondents agreed that Junior Rounds met their educational needs, was presented at an appropriate level, and was more important to their l...
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Changing the default for peripherally inserted central catheters (PICCs) ordered from non-critical care units to single-lumen devices resulted in a sustained reduction in PICC-related complications. This system of care would be... more
Changing the default for peripherally inserted central catheters (PICCs) ordered from non-critical care units to single-lumen devices resulted in a sustained reduction in PICC-related complications. This system of care would be transferrable to other institutions with potential for improved patient safety and efficiency in outpatient parenteral antimicrobial therapy clinics.
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Medical training poses many challenges to trainees' wellbeing. To address the impact of learning in a high turnover, high volume, acute care setting in the General Internal Medicine Clinical Teaching Unit, the Chief Medical Resident,... more
Medical training poses many challenges to trainees' wellbeing. To address the impact of learning in a high turnover, high volume, acute care setting in the General Internal Medicine Clinical Teaching Unit, the Chief Medical Resident, in this personal account, shares how she and the Spiritual Care Practitioner united to form an innovative partnership. The introduction of the skills of spiritual care practitioners, generally referred to patients and families, to support medical students and residents resulted in the co-development and co-implementation of a unique, reflective, one-hour session. The objective was to create a protected space and time to discuss the impact of training and clinical experiences on medical trainees' wellbeing, in the context of "living from the heart".
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Tongue piercing has become an increasingly popular form of body art. However, this procedure can occasionally be complicated by serious bacterial infections. The present article reports a case of prosthetic valve endocarditis caused by... more
Tongue piercing has become an increasingly popular form of body art. However, this procedure can occasionally be complicated by serious bacterial infections. The present article reports a case of prosthetic valve endocarditis caused by aGemellaspecies in a patient with a pierced tongue, and reviews 18 additional cases of local and systemic bacterial infections associated with tongue piercing. Infections localized to the oral cavity and head and neck region included molar abscess, glossal abscess, glossitis, submandibular lymphadenitis, submandibular sialadenitis, Ludwig’s angina and cephalic tetanus. Infections distal to the piercing site included eight cases of infective endocarditis, one case of chorioamnionitis and one case of cerebellar abscess. Oropharyngeal flora were isolated from all cases. While bacterial infections following tongue piercing are rare, there are reports of potentially life-threatening infections associated with the procedure. Both piercers and their clients ...
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BACKGROUND: Rising costs present a major threat to the sustainability of health care delivery. Resource stewardship is increasingly becoming an expected competency of physicians. The Choosing Wisely framework was used to introduce... more
BACKGROUND: Rising costs present a major threat to the sustainability of health care delivery. Resource stewardship is increasingly becoming an expected competency of physicians. The Choosing Wisely framework was used to introduce resource stewardship at a national educational retreat for infectious disease and microbiology residents.METHODS: During the 2014 Annual Canadian Infectious Disease and Microbiology Resident Retreat in Toronto, Ontario, infectious disease (n=50) and microbiology (n=17) residents representing 11 Canadian universities from six provinces, were invited to participate in a modified Delphi panel. Participants were asked, in advance of the retreat, to submit up to five practices that infectious disease and microbiology specialists should not routinely perform due to lack of proven benefit(s) and/or potential harm to patients. Submissions were discussed in small and large group forums using an iterative approach involving electronic polling until consensus was rea...
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Pneumococcal disease burden is difficult to quantify due to limited data regarding non-bacteremic disease. We assessed serotype-specific differences in pneumococcal disease presentations in adults in Toronto, Canada. From 2003 to 2011,... more
Pneumococcal disease burden is difficult to quantify due to limited data regarding non-bacteremic disease. We assessed serotype-specific differences in pneumococcal disease presentations in adults in Toronto, Canada. From 2003 to 2011, population-based surveillance for invasive pneumococcal disease was conducted and respiratory pneumococcal isolates collected in Metropolitan Toronto/Peel Region, Canada. Episodes of care were classified into disease categories. Of 3105 eligible cases of IPD, 2060 cases were bacteremic pneumonia, and 1045 bacteremia without pneumonia. Of 2751 eligible respiratory cases, 1542 (35.0%) were non-bacteremic pneumonia (NBPP), 467 (11.0%) were other acute respiratory infection (oARI), and 742 (17.1%) were isolates representing colonization. Serotypes 3 (11.3%), 19A (8.4%) and 22F (6.2%) were the most common; serotypes 1,5, and 8 were rare. Serotypes 4, 14, 7F, 9V, 12F, 14, 19A and 6C were over-represented in bacteremic disease, and serotypes 3, 6A, 11A, 19F, 23A, 23B, 23F, 35B, 35F were more common in NBPP. The proportion of cases due to PCV7 serotypes declined from 48.7% to 8.7% in bacteremic pneumonia, from 35.3% to 10.9% in NBPP, from 34.2% to 7.5% in oARI, and from 38.7% to 12.2% in colonizing isolates. In 2010-2011, PCV13 serotypes accounted for 62.6% of isolates associated with bacteremic pneumonia, 42.0% of bacteremia without pneumonia, 41.1% of NBPP, 25.7% of oARI, and 32.9% of colonizing isolates. Serotype distributions differ significantly in different presentations of pneumococcal disease. Herd protection due to PCV7 has changed serotype distribution, but PCV13 serotypes remain important in all categories of disease.
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In 2012/3, a single dose of 13-valent pneumococcal conjugate vaccine (PCV13) was recommended for immunocompromised adults in the United States and Canada. To assess the potential benefits of this recommendation, we assessed the serotype... more
In 2012/3, a single dose of 13-valent pneumococcal conjugate vaccine (PCV13) was recommended for immunocompromised adults in the United States and Canada. To assess the potential benefits of this recommendation, we assessed the serotype specific burden of invasive pneumococcal disease (IPD) among immunocompromised individuals. From 1995 to 2012 population-based surveillance for IPD was conducted in Metropolitan Toronto and Peel Region, Canada. Disease incidence and case fatality were measured in immunocompromised populations over time, and the contribution of different serotypes determined. Overall, 2115/7604 (28%) episodes of IPD occurred in immunocompromised persons. IPD incidence was 12 fold higher (95% CI 8.7-15) in immunocompromised compared to immunocompetent persons; the case fatality rate was elevated in both younger (OR 1.8) and older (OR 1.3) adults. Use of immunosuppressive medications was associated with a 2.1-2.7 fold increase in the risk of IPD. Five years after PPV...
Research Interests: Adolescent, Streptococcus pneumoniae, Biological Sciences, Canada, Humans, and 15 moreChild, Female, Infant, Incidence, Aged, Middle Aged, Adult, Immunocompromised host, Oxford university, Clinical Infectious Diseases, Pneumococcal Vaccines, Cohort Studies, Child preschool, Medical and Health Sciences, and Serogroup
Background: Since 2002, coincident with an increase in reported cases of infectious syphilis in Toronto, Canada, less common presentations of the disease have been observed among persons with HIV co-infection. We review the clinical and... more
Background: Since 2002, coincident with an increase in reported cases of infectious syphilis in Toronto, Canada, less common presentations of the disease have been observed among persons with HIV co-infection. We review the clinical and laboratory features and treatment outcomes of seven HIV-positive patients with auditory syphilis. Methods: Patient interview and chart review of cases identified at teaching hospitals and clinics affiliated with the Univ. of Toronto. Results: All patients presented with tinnitus; 6 of 7 patients (86%) reported hearing loss. Excluding auditory findings, 3 patients were classified as having secondary syphilis, 2 patients as having early latent syphilis, and 2 patients as having late latent syphilis. Four of seven patients (57%) had concomitant neurosyphilis according to CSF (cerebrospinal fluid) analysis. Three of these four patients had a positive CSF VDRL (Venereal Disease Research Laboratory) result with a mean titre of 1:4. The mean CSF white blood...
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Background: Gentamicin is used for the treatment of resistant gram-negative bacterial infections. Studies comparing single-daily dosing (SDD) to multiple-daily dosing (MDD) show similar efficacy and less nephrotoxicity. Less is known... more
Background: Gentamicin is used for the treatment of resistant gram-negative bacterial infections. Studies comparing single-daily dosing (SDD) to multiple-daily dosing (MDD) show similar efficacy and less nephrotoxicity. Less is known about the effects of different dosing regimens on the development of ototoxicity. Among patients referred to our Multidisciplinary Neurotology Clinic (MNC), we compared the impact of SDD versus MDD of gentamicin in patients without acute kidney injury (AKI) on the development of vestibulotoxicity. Methods: Data was collected for consecutive patients referred to our MNC between 1993 and 2012, including patient demographics, medical co-morbidities, concurrent medications, gentamicin dosing regimen, indications for use, cumulative dose and duration of therapy-to-time of diagnosis of vestibulotoxicity, and presence of AKI, determined by history or 1.5-fold elevation in serum creatinine. Results: Forty-six patients were identified of whom 19 (43.1%) had no e...
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Background: Clostridium difficile infection (CDI) is the most common cause of nosocomial diarrhea and often results in severe complications including sepsis, colectomy and death. We conducted a prospective study to identify risk factors... more
Background: Clostridium difficile infection (CDI) is the most common cause of nosocomial diarrhea and often results in severe complications including sepsis, colectomy and death. We conducted a prospective study to identify risk factors for complications or death due to CDI. Methods: Adult inpatients with confirmed CDI in 10 acute care hospitals across Quebec and Ontario, Canada, were enrolled in a prospective cohort between 2005 and 2008. A follow-up was performed on day 30 and 90 after enrollment. CDI was defined by diarrhea and a positive toxin (EIA or direct cytotoxin). Complicated CDI (cCDI) was confirmed if one or more of the following was observed: colonic perforation, toxic megacolon, septic shock, colectomy or death within 30 days. Data on potential factors predictive of cCDI were collected within 48 hours of the diagnosis. Isolates were typed by PCR-ribotyping. A multivariate logistic regression model was used to identify predictors of cCDI. Results: A total of 1380 patien...
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A case of Bacille Calmette-Guerin (BCG)-associated epididymitis that was non responsive to 6 months of antituberculous therapy, but stable after 2 years, is reported. We review the clinical and pathological features of previously reported... more
A case of Bacille Calmette-Guerin (BCG)-associated epididymitis that was non responsive to 6 months of antituberculous therapy, but stable after 2 years, is reported. We review the clinical and pathological features of previously reported cases of pathologically diagnosed BCG-associated epididymitis. Surgery has been the primary treatment for BCG-associated epididymitis in all previous cases.
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Background: In August, 2005, the Central Public Health Laboratory (CPHL) in Toronto, Ontario introduced the Enzygnost (Dade Behring) enzyme immunoassay (EIA) as the screening test for syphilis, replacing the RPR. The EIA is a treponemal... more
Background: In August, 2005, the Central Public Health Laboratory (CPHL) in Toronto, Ontario introduced the Enzygnost (Dade Behring) enzyme immunoassay (EIA) as the screening test for syphilis, replacing the RPR. The EIA is a treponemal specific assay with higher reported sensitivity and specificity than the RPR. It may remain positive for life. The current CPHL protocol is to screen with the EIA and confirm all positive results with both an RPR and another treponemal specific test (treponemal pallidum particle agglutination). Previously, all RPR+ results were confirmed with another treponemal specific test. Methods: Results of testing were compared for two similar calendar time periods: (A) RPR screening, September 2004 - February 2005 (N = 10 480 specimens tested) and (B) EIA screening, September 2005 - February 2006 (N = 106,882 specimens tested). Results: During period (A), 1734 (16.5%) were positive on screening (RPR+). During period (B), 3659 (3.4%) were positive on screening ...
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An outbreak of severe acute respiratory syndrome (SARS) began in Canada in February 2003. The initial diagnosis of SARS was based on clinical and epidemiological criteria. During the outbreak, molecular and serologic tests for the... more
An outbreak of severe acute respiratory syndrome (SARS) began in Canada in February 2003. The initial diagnosis of SARS was based on clinical and epidemiological criteria. During the outbreak, molecular and serologic tests for the SARS-associated coronavirus (SARS-CoV) became available. However, without a "gold standard," it was impossible to determine the usefulness of these tests. We describe how these tests were used during the first phase of the SARS…
Research Interests: Adolescent, Medicine, Humans, Female, Male, and 15 moreDifferential Diagnosis, Ontario, Aged, Middle Aged, Gold Standard, Adult, Diagnostic Test, Severe Acute Respiratory Syndrome (SARS), Sensitivity and Specificity, Laboratory Tests, Confidence Interval, Lower respiratory tract, reverse transcriptase polymerase chain reaction, Severe Acute Respiratory Syndrome, and Medical and Health Sciences
Research Interests: Adolescent, Medicine, Biological Sciences, Canada, Humans, and 15 moreChild, Female, Male, Infant, Aged, Adult, Acinetobacter, Microbial Sensitivity Tests, Cross Sectional Studies, Clinical Infectious Diseases, Acinetobacter Infections, Child preschool, Medical and Health Sciences, Cross Infection, and Epidemiological monitoring
Research Interests: Educational Measurement, Medical Education, Problem Based Learning, Blogging, Teaching, and 14 moreHumans, Internal Medicine, Data Collection, Ontario, North America, Survey data, Medical Image, Curriculum and Pedagogy, Educational Status, Case Based Learning, Training Program, Internet, web metrics, and Pharmacology and pharmaceutical sciences
In 2005, syphilis screening in the Greater Toronto Area of Canada moved from the rapid plasma reagin (RPR) to a treponemal enzyme immunoassay (EIA). We sought to understand the consequences of this change on laboratory results and testing... more
In 2005, syphilis screening in the Greater Toronto Area of Canada moved from the rapid plasma reagin (RPR) to a treponemal enzyme immunoassay (EIA). We sought to understand the consequences of this change on laboratory results and testing patterns with a population-based retrospective study of laboratory-based diagnoses of syphilis. Samples positive under RPR (1998-2005) and EIA (2005-2008) screening were confirmed with an alternate treponemal test, and during the latter period underwent RPR testing. We compared monthly rates and the forecasting relationship between positives and future submissions with time-series methods, and assessed risk factors for EIA(+)/RPR(-) results using Poisson regression. A total of 3,092,938 submissions were included. Following EIA implementation, confirmed positive rates increased by 10.3 per 100,000 population (P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). 0.59% of EIA(+)/RPR(-) individuals converted to RPR(+) within 2 months. EIA(+)/RPR(-) patients were more likely to be male (incidence rate ratio [IRR]: 2.3, 95% confidence interval [CI]: 1.6-2.5), asymptomatic (IRR: 1.8, 95% CI: 1.3-2.8), and aged&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;50 years (IRR: 2.4, 95% CI: 1.6-3.5) than those with EIA(+)/RPR(+) results. We detected a significant positive feedback loop between positive tests and subsequent submissions. This relationship was only transiently evident for EIA(+)/RPR(-) results up to 1 year following the changeover. EIA screening facilitates identification of probable latent syphilis and earlier serological detection of infectious syphilis, but may transiently cause increases in testing and indirectly suggests that physicians&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; interpretation of RPR(-) serology may lead to partner testing. In the absence of a true gold standard, implementation of EIA screening warrants careful communication regarding serological interpretation.