Peter Daley

• The primary goal of testing for tuberculosis infection is to identify individuals who are at increased risk for the development of tuberculosis disease and who therefore would benefit from tuberculosis preventive treatment. • Testing for tuberculosis infection is NOT recommended in the following situations: ○ In persons who have a low risk of infection and if infected; ○ To support a tuberculosis disease diagnosis in adults and adolescents >12 years of age; ○ For routine mass screening of individuals outside of contact investigations or occupational screening programs; and ○ For the monitoring of tuberculosis disease treatment response. • Both the tuberculin skin test and interferon-gamma release assay are acceptable alternatives for tuberculosis infection diagnosis. Either test can be used for tuberculosis infection screening in any of the situations in which testing is indicated. However, there are preferences and exceptions: ○ An interferon-gamma release assay is the preferred test when: ○ children over two years of age and less than 10 years of age previously received a Bacille Calmette-Guérin (BCG) vaccine against tuberculosis; ○ persons at least 10 years of age received a BCG vaccine after infancy (older than one year of age), or received a BCG vaccine more than once and/or are uncertain about when they received a BCG vaccine; ○ adequate training and quality assessment and control are NOT available for tuberculin skin test administration and/or reading, but personnel and facilities to perform interferon-gamma release assays are available; ○ a person is unable or unlikely to return to have their tuberculin skin test read; or ○ tuberculin skin testing is contraindicated. ○ The tuberculin skin test is the preferred test when serial testing is planned to assess risk of new infection (ie, conversions). This includes repeat testing in a contact investigation, or serial testing of health care workers or other populations (eg, corrections staff or prison inmates) with potential for ongoing exposure. In these situations, interferon-gamma release assays are not acceptable. • Both tuberculosis infection diagnostic tests may be used sequentially in the following situations: ○ If either the tuberculin skin test or interferon-gamma release assay are negative, the other test may be used to increase sensitivity if the risk for infection is high, the risk for progression to tuberculosis disease is elevated, the risk for a poor outcome from tuberculosis disease is high and/or a person has conditions or habits that may reduce the sensitivity of the test. ○ If the initial tuberculin skin test is positive, but the likelihood of tuberculosis infection is low, or risk of a false positive result due to BCG is high, then an interferon-gamma release assay may be used to increase specificity. • When interpreting a tuberculosis infection diagnostic test result and considering whether someone is at risk of developing tuberculosis disease and would likely benefit from tuberculosis preventive treatment, the diagnostic test result should be considered in light of other factors, including the pretest probability for the person being truly infected, the individual risk of developing tuberculosis disease and the ability of the test to identify persons at risk of tuberculosis disease (ie, predictive value). Online tools exist to support this interpretation.

Commercial point-of-care (POC) diagnostic tests for Group A Streptococcus, Streptococcus pneumoniae, and influenza virus have large potential diagnostic and financial impact. Many published reports on test performance, often funded by diagnostics companies, are prone to bias. The Standards for Reporting of Diagnostic Accuracy (STARD 2015) are a protocol to encourage accurate, transparent reporting. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool evaluates risk of bias and transportability of results. We used these tools to evaluate diagnostic test accuracy studies of POC studies for three respiratory pathogens. For the 96 studies analysed, compliance was <25% for 14/34 STARD 2015 standards, and 3/7 QUADAS-2 domains showed a high risk of bias. All reports lacked reporting of at least one criterion. These biases should be considered in the interpretation of study results.

Rat bite fever is rare in Western countries. It can be very difficult to diagnose as blood cultures are typically negative and a history of rodent exposure is often missed. Unless a high index of suspicion is maintained, the associated polyarthritis can be mistaken for rheumatoid arthritis. We report a case of culture-positive rat bite fever in a 46-year-old female presenting with fever and polyarthritis. The clinical presentation mimicked rheumatoid arthritis. Infection was complicated by discitis, a rare manifestation. We discuss the diagnosis and management of this rare zoonotic infection. We also review nine reported cases of rat bite fever, all of which had an initial presumptive diagnosis of a rheumatological disorder. Rat bite fever is a potentially curable infection but can have a lethal course if left untreated.

INTRODUCTION Urine specimens for quantitative culture for the diagnosis of urinary tract infection may be unreliable due to bacterial overgrowth within 4 h after collection, at room temperature. Because specimen transportation may take longer than 4 h, urine preservatives may reduce overgrowth. Further evidence is needed to support a recommendation for use of preservative and to compare preservative products. METHODS Consecutive midstream urine specimens submitted for culture were quantitatively cultured on receipt and then inoculated into 3 storage conditions [BD Urine Vacutainer (BD), Copan UriSwab (US), and refrigeration, with a room temperature control] for 72 h, with quantitative culture performed every 24 h. Odds ratio for significant growth interpretation was reported. RESULTS Ninety-five of 501 (19.0%) urine specimens demonstrated significant growth. Within 24 h of storage, unpreserved urine at room temperature demonstrated a significantly increased odds ratio for significan...

Background: Stewardship of microbiological tests can improve laboratory efficiency. One indicator of appropriate test stewardship is test impact on patient management decisions. We sought to assess the impact of cerebrospinal fluid (CSF) Gram stain and culture results on treatment decisions. Our hypothesis was that CSF Gram stain and culture have low impact on patient management. Methods: CSF specimens received at a tertiary microbiology laboratory between January 1, 2013, and December 31, 2013, were included. Clinical information and data on antibiotic treatment before CSF collection, antibiotic treatment after CSF Gram stain results, and antibiotic treatment after CSF culture results were collected. Ethics approval for secondary use of data was obtained. Results: We received 242 CSF specimens for Gram stain and culture during the study period; 120 were excluded (84 from children, 2 from indwelling ventricular drains, 12 collected at outside hospitals, 21 data missing, 1 duplicate)...

Objectives Inappropriate antibiotic use contributes to antimicrobial resistance. The SpectrumTM app provides antibiotic decision support, based on local antimicrobial resistance rates. We determined the impact of regional implementation of the app on inpatient antimicrobial appropriateness, inpatient antimicrobial usage (AMU), population-based Clostridioides difficile infection (CDI) rates and cost, using a retrospective, before and after quasi-experimental design, including a one-year study period. Methods The SpectrumTM app was released to prescribers in February, 2019. We performed two one-day inpatient point prevalence surveys using the National Antimicrobial Prescribing Survey tool, six months before (June 25, 2018) and six months after (June 25, 2019) app dissemination. Inpatient AMU in Defined Daily Dose/1000 patient days and CDI incidence were compared, before and after app dissemination. Results The pre-survey included 184 prescriptions, and the post-survey included 197 pre...

Background: Late diagnosis of HIV is associated with poor outcomes and increased cost. Novel HIV testing promotion strategies may reduce late diagnosis. The purpose of this study was to determine the timeliness of HIV testing in Newfoundland and Labrador (NL), missed opportunities for testing, and barriers to HIV testing. Methods: Demographic and clinical information from individuals diagnosed with HIV in NL from 2006–2016 was retrospectively reviewed. Patients were also invited to participate in semi-structured interviews regarding knowledge about HIV transmission, risk associated with their behaviour, testing decision making, and testing opportunities. Results: Fifty-eight new HIV diagnoses occurred during the study period: 53/58 (91.4%) were male and 33/58 (56.9%) were men who have sex with men. The mean age at diagnosis was 40.6 (SD 11.05) years. CD4 count at diagnosis ranged from 2 to 1,408 cells/mm3, with a mean of 387 cells/mm3. For 39/58 (67.2%) of individuals, the first-eve...

Background: Surveillance of the appropriateness of antimicrobial prescribing can identify targets for quality improvement in antimicrobial stewardship. Our objective was to measure antibiotic prescription prevalence, indication, and appropriateness at three rural community hospitals in a 1-day point prevalence study. Methods: Inpatient antibiotic prescriptions given at three community hospitals on April 24, 2019 were provided by the hospital pharmacies. These prescriptions were analyzed using the Australian National Antimicrobial Prescribing Survey (NAPS) tool. Prescriptions were assessed by an infectious diseases physician and analyzed per prescription. Results: Eighty prescriptions given to 58 inpatients were included. Antibiotic treatment prevalence was 58/120 beds (48.3%), and overall appropriateness was 37/80 prescriptions (46.3%). The most prescribed antibiotics were ceftriaxone (17 [21.3%]; 47.1% appropriate), piperacillin–tazobactam (10 [12.5%]; 10.0% appropriate), and moxif...

Background: Choosing Wisely Canada is a forum for health care professional societies to lead system change through identification and reduction of low-value practices. Microbiologic investigations are frequently overused and may contribute to unnecessary health care expenditures as well as patient harm. Methods: A Choosing Wisely Canada top five list in medical microbiology was developed by the Association of Medical Microbiology and Infectious Disease (AMMI) Canada through broad consultation of its members. Following an electronic survey of members, recommendations were developed and ranked by a working group, then further narrowed during a national open forum using the modified Delphi method. Feedback was solicited through an online forum prior to dissemination. Results: The top five declarative statements in medical microbiology are: (1) Don’t collect urine specimens for culture from adults who lack symptoms localizing to the urinary tract or fever, (2) Don’t routinely collect or...

DESIGNWe conducted a randomized, parallel, unblinded, superiority trial of a laboratory reporting intervention designed to reduce antibiotic treatment of asymptomatic bacteriuria (ASB).METHODSResults of positive urine cultures from 110 consecutive inpatients at 2 urban acute-care hospitals were randomized to standard report (control) or modified report (intervention). The standard report included bacterial count, bacterial identification, and antibiotic susceptibility information including drug dosage and cost. The modified report stated: "This POSITIVE urine culture may represent asymptomatic bacteriuria or urinary tract infection. If urinary tract infection is suspected clinically, please call the microbiology laboratory … for identification and susceptibility results." We used the following exclusion criteria: age <18 years, pregnancy, presence of an indwelling urinary catheter, samples from patients already on antibiotics, neutropenia, or admission to an intensive c...

Background. Acute pharyngitis caused by Group A Streptococcus (GAS) is a common presentation to pediatric emergency departments (ED). Diagnosis with conventional throat culture requires 18-24 hours, which prevents point-of-care treatment decisions. Rapid antigen detection tests (RADT) are faster, but previous reports demonstrate significant operator influence on performance. Objective. To measure operator influence on the diagnostic accuracy of a RADT when performed by pediatric ED nurses and clinical microbiology laboratory technologists, using conventional culture as the reference standard. Methods. Children presenting to a pediatric ED with suspected acute pharyngitis were recruited. Three pharyngeal swabs were collected at once. One swab was used to perform the RADT in the ED, and two were sent to the clinical microbiology laboratory for RADT and conventional culture testing. Results. The RADT when performed by technologists compared to nurses had a 5.1% increased sensitivity (8...

Sequencing of the 16S gene or other targets and line probe assay are in wide use for the identification of nontuberculous mycobacteria. We compared in-house and commercial sequencing with 3 sequence databases against high-performance liquid chromatography (HPLC) and line ...

Methicillin-resistant Staphylococcus aureus (MRSA) infections are common among humans in Aboriginal communities in Canada, for unknown reasons. Cross sectional study of humans and dogs in an Aboriginal community of approximately 1200 persons. Our objectives were to measure community-based prevalence of nasal MRSA colonization among humans, use multivariable logistic regression to analyze risk factors for MRSA colonization, and perform molecular typing of Staphylococci isolated to investigate interspecies transmission. 461 humans were approached for consent and 442 provided complete data. 109/442 (24.7 %, 95 % C.I. = 20.7-28.7 %) of humans were colonized with MRSA. 169/442 (38.2 %) of humans had received antibiotics in the last 12 months. Only number of rooms in the house (OR 0.86, p = 0.023) and recreational dog use (OR 7.7, p = 0.002) were significant risk factors for MRSA colonization. 95/109 (87.1 %) of MRSA strains from humans were of the same spa type (CMRSA10/USA300). 8/157 (5...

Acute upper respiratory tract infections are the most com- mon cause of illness in children (3) and in the institutionalized elderly. Timely laboratory diagnosis may allow specific anti- viral therapy, avoidance or discontinuation of antibacterial agents, appropriate institutional infection control measures, and improved surveillance. Rapid testing with direct fluores- cent antibody (DFA) shortens the time to laboratory diagnosis for upper

Traditional methods for laboratory diagnosis of tuberculosis (TB) may require weeks, and delay can impede treatment and control efforts. Nucleic acid amplification (NAA) tests, such as polymerase chain reaction (PCR) and other methods for amplifying DNA and RNA, may facilitate rapid detection of microorganisms. An NAA test for Mycobacterium tuberculosis complex (Amplified Mycobacterium Tuberculosis Direct Test of MTD [Gen-Probe, San Diego, California]) was recently approved by the Food and Drug Administration (FDA) for use on processed clinical specimens, and others are under development. Although NAA tests have been offered by individual laboratories, approval of commercial kits may result in increased use for clinical practice and TB control. This report summarizes potential uses of NAA tests for TB diagnosis and provides interim guidelines for the use of such tests.