Province-Wide Review of Pediatric Shiga Toxin-Producing Escherichia coli Case Management.

OBJECTIVE: To identify the gaps in the care of children infected with Shiga toxin-producing Escherichia coli (STEC), we sought to quantitate care received and management timelines. Such knowledge is crucial to the design of interventions to prevent the development of hemolytic uremic syndrome (HUS). STUDY DESIGN: We conducted a retrospective case-series study of 78 children infected with STEC in Alberta, Canada, through the linkage of microbiology and laboratory results, telephone health advice records, hospital charts, physician billing submissions, and outpatient antimicrobial dispensing databases. Outcomes were the time intervals between initial presentation and reporting of positive culture result and symptom onset to HUS and to describe the proportions that had baseline blood work performed and received antibiotics. RESULTS: Seventy-eight children infected with STEC were identified; 13% (10/78) developed HUS. Median time from initial presentation to laboratory stool sample receipt was 33 hours (IQR 18, 42); time to positive culture was 120 hours (IQR 86, 205). Time from symptom onset to HUS diagnosis was 188 ± 37 hours. Baseline blood tests were obtained in 74% (58/78) of infected children. Antibiotics were administered to 50% (5/10) of those who developed HUS and 22% (15/78) of those who did not; P = .11. The provincial telephone advice system received 31 calls regarding 24 children infected with STEC; 23% (7/31) of callers were recommended to seek emergency department care. CONCLUSIONS: A significant proportion of children developed HUS following multiple interactions with the health care system. Delays in the confirmation of STEC infection occurred. There are numerous opportunities to improve the timing, monitoring, and interventions in children infected with STEC.

Physician perspectives on vaccination and diagnostic testing in children with gastroenteritis: A primary care physician survey.

OBJECTIVES: Gastroenteritis remains a common paediatric illness. Little is known about physician knowledge of enteric pathogen diagnostic tests. At the time of study conduct, Alberta lacked a publicly funded rotavirus vaccination program and knowledge of primary care physician perspectives was lacking. We sought to ascertain diagnostic testing methods and to understand knowledge and perceptions regarding enteric pathogen vaccination. METHODS: A 30-item electronic survey was distributed across Alberta's five health care zones. The survey was developed by virology, microbiology, paediatrics, family medicine and public health experts. Participants were members of Alberta's Primary Care Networks, the TARRANT network and The Society of General Pediatricians of Greater Edmonton. Study outcomes included: (1) physician knowledge of available diagnostic tests, (2) perspectives regarding stool sample collection and (3) support for an enteric vaccine program. RESULTS: Stool culture was reported as the test to identify parasites (47%), viruses (74%) and Clostridium difficile (67%). Although electron microscopy and enzyme immunoassay were used to identify viruses in Alberta during the study period, only 20% and 48% of respondents respectively identified them as tests employed for such purposes. Stool testing was viewed as being inconvenient (62%; 55/89), whereas rectal swabs were thought to have the potential to significantly improve specimen collection rates (82%; 72/88). Seventy-three per cent (66/90) of the respondent physicians support the adoption of future enteric pathogen vaccines. CONCLUSIONS: Simplification of diagnostic testing and stool sample collection could contribute to improved pathogen identification rates. Implementation of an enteric vaccine into the routine paediatric vaccination schedule is supported by the majority of respondents.

Shiga Toxin-Producing Escherichia coli Infection, Antibiotics, and Risk of Developing Hemolytic Uremic Syndrome: A Meta-analysis.

BACKGROUND: Antibiotic administration to individuals with Shiga toxin-producing Escherichia coli (STEC) infection remains controversial. We assessed if antibiotic administration to individuals with STEC infection is associated with development of hemolytic uremic syndrome (HUS). METHODS: The analysis included studies published up to 29 April 2015, that provided data from patients (1) with STEC infection, (2) who received antibiotics, (3) who developed HUS, and (4) for whom data reported timing of antibiotic administration in relation to HUS. Risk of bias was assessed; strength of evidence was adjudicated. HUS was the primary outcome. Secondary outcomes restricted the analysis to low-risk-of-bias studies employing commonly used HUS criteria. Pooled estimates of the odds ratio (OR) were obtained using random-effects models. RESULTS: Seventeen reports and 1896 patients met eligibility; 8 (47%) studies were retrospective, 5 (29%) were prospective cohort, 3 (18%) were case-control, and 1 was a trial. The pooled OR, including all studies, associating antibiotic administration and development of HUS was 1.33 (95% confidence interval [CI], .89-1.99; I(2) = 42%). The repeat analysis including only studies with a low risk of bias and those employing an appropriate definition of HUS yielded an OR of 2.24 (95% CI, 1.45-3.46; I(2) = 0%). CONCLUSIONS: Overall, use of antibiotics was not associated with an increased risk of developing HUS; however, after excluding studies at high risk of bias and those that did not employ an acceptable definition of HUS, there was a significant association. Consequently, the use of antibiotics in individuals with STEC infections is not recommended.

Alberta Provincial Pediatric EnTeric Infection TEam (APPETITE): epidemiology, emerging organisms, and economics.

BACKGROUND: Each year in Canada there are 5 million episodes of acute gastroenteritis (AGE) with up to 70% attributed to an unidentified pathogen. Moreover, 90% of individuals with AGE do not seek care when ill, thus, burden of disease estimates are limited by under-diagnosing and under-reporting. Further, little is known about the pathogens causing AGE as the majority of episodes are attributed to an "unidentified" etiology. Our team has two main objectives: 1) to improve health through enhanced enteric pathogen identification; 2) to develop economic models incorporating pathogen burden and societal preferences to inform enteric vaccine decision making. METHODS/DESIGN: This project involves multiple stages: 1) Molecular microbiology experts will participate in a modified Delphi process designed to define criteria to aid in interpreting positive molecular enteric pathogen test results. 2) Clinical data and specimens will be collected from children aged 0-18 years, with vomiting and/or diarrhea who seek medical care in emergency departments, primary care clinics and from those who contact a provincial medical advice line but who do not seek care. Samples to be collected will include stool, rectal swabs (N = 2), and an oral swab. Specimens will be tested employing 1) stool culture; 2) in-house multiplex (N = 5) viral polymerase chain reaction (PCR) panel; and 3) multi-target (N = 15) PCR commercially available array. All participants will have follow-up data collected 14 days later to enable calculation of a Modified Vesikari Scale score and a Burden of Disease Index. Specimens will also be collected from asymptomatic children during their well child vaccination visits to a provincial public health clinic. Following the completion of the initial phases, discrete choice experiments will be conducted to enable a better understanding of societal preferences for diagnostic testing and vaccine policy. All of the results obtained will be integrated into economic models. DISCUSSION: This study is collecting novel samples (e.g., oral swabs) from previously untested groups of children (e.g., those not seeking medical care) which are then undergoing extensive molecular testing to shed a new perspective on the epidemiology of AGE. The knowledge gained will provide the broadest understanding of the epidemiology of vomiting and diarrhea of children to date.

The utility of multiple molecular methods including whole genome sequencing as tools to differentiate Escherichia coli O157:H7 outbreaks.

A standardised method for determining Escherichia coli O157:H7 strain relatedness using whole genome sequencing or virulence gene profiling is not yet established. We sought to assess the capacity of either high-throughput polymerase chain reaction (PCR) of 49 virulence genes, core-genome single nt variants (SNVs) or k-mer clustering to discriminate between outbreak-associated and sporadic E. coli O157:H7 isolates. Three outbreaks and multiple sporadic isolates from the province of Alberta, Canada were included in the study. Two of the outbreaks occurred concurrently in 2014 and one occurred in 2012. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem repeat analysis (MLVA) were employed as comparator typing methods. The virulence gene profiles of isolates from the 2012 and 2014 Alberta outbreak events and contemporary sporadic isolates were mostly identical; therefore the set of virulence genes chosen in this study were not discriminatory enough to distinguish between outbreak clusters. Concordant with PFGE and MLVA results, core genome SNV and k-mer phylogenies clustered isolates from the 2012 and 2014 outbreaks as distinct events. k-mer phylogenies demonstrated increased discriminatory power compared with core SNV phylogenies. Prior to the widespread implementation of whole genome sequencing for routine public health use, issues surrounding cost, technical expertise, software standardisation, and data sharing/comparisons must be addressed.

Multi-Province Listeriosis Outbreak Linked to Contaminated Deli Meat Consumed Primarily in Institutional Settings, Canada, 2008.

A multi-province outbreak of listeriosis occurred in Canada from June to November 2008. Fifty-seven persons were infected with 1 of 3 similar outbreak strains defined by pulsed-field gel electrophoresis, and 24 (42%) individuals died. Forty-one (72%) of 57 individuals were residents of long-term care facilities or hospital inpatients during their exposure period. Descriptive epidemiology, product traceback, and detection of the outbreak strains of Listeria monocytogenes in food samples and the plant environment confirmed delicatessen meat manufactured by one establishment and purchased primarily by institutions was the source of the outbreak. The food safety investigation identified a plant environment conducive to the introduction and proliferation of L. monocytogenes and persistently contaminated with Listeria spp. This outbreak demonstrated the need for improved listeriosis surveillance, strict control of L. monocytogenes in establishments producing ready-to-eat foods, and advice to vulnerable populations and institutions serving these populations regarding which high-risk foods to avoid.

Emergence of new CMRSA7/USA400 methicillin-resistant Staphylococcus aureus spa types in Alberta, Canada, from 2005 to 2012.

Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the most significant pathogens affecting global public health and health care systems. In Canada and the United States, the spread of MRSA is primarily attributed to a single dominant epidemic clone: CMRSA10/USA300. Despite this, the CMRSA7/USA400 epidemic clone has been reported to be the predominate epidemic clone in several Canadian provinces and some parts of the United States. This study examined the epidemiology of CMRSA7/USA400 MRSA in Alberta, Canada, from June 2005 to December 2012. Molecular characterization of CMRSA7/USA400 isolates was done using spa, SCCmec, PVL, and PFGE typing and identified two predominant spa types in Alberta: t128 and t1787. Although closely related, these spa types have distinct geographic distributions. From 2010 to 2012, the number of t128 infections has remained stable while there has been a nearly 3-fold increase in the number of provincial t1787 infections, accompanied by 10-fold increases in t1787 infection rates in some communities. Most t128 and t1787 patients were First Nations or Inuit people, and isolates were usually from skin and soft tissue infections in outpatients. t128 patients were significantly older than t1787 patients. Antimicrobial susceptibility testing showed higher mupirocin resistance in t1787 than in t128 MRSA. Improved strategies to reduce or stabilize t1787 infections in Alberta are needed.

Emergence of multidrug-resistant Salmonella enterica serotype 4,[5],12:i:- involving human cases in Canada: results from the Canadian Integrated Program on Antimicrobial Resistance Surveillance (CIPARS), 2003-10.

OBJECTIVES: Over the last decade, a marked increase in Salmonella enterica serotype 4,[5],12:i:- with a core resistance to ampicillin, streptomycin, sulphonamides and tetracycline (ASSuT) has been observed in Europe. This study describes the emergence and characterization of isolates of multidrug-resistant Salmonella 4,[5],12:i:- in Canada. METHODS: Human clinical isolates of Salmonella 4,[5],12:i:- were identified by provincial laboratories from 2003 to 2010. Serotyping and phage typing were performed by standardized methodologies. MIC values were determined using broth microdilution. PCR was used to determine the presence of resistance genes. Multilocus sequence typing was performed on a selected number of isolates. RESULTS: A total of 26 251 Salmonella were submitted as part of the Canadian Integrated Program on Antibiotic Resistance Surveillance (CIPARS). Of these, Salmonella 4,[5],12:i:- accounted for a total of 766 isolates (2.9%), and the number increased significantly from 42 (1.4%) in 2003 to 164 (4.8%) in 2010. The ASSuT+ phenotype was observed in 11.9% (n = 91) of Salmonella 4,[5],12:i:- isolates and increased from two isolates in 2003 to 35 isolates in 2010. Two sequence types (STs) were observed. ST34 was mainly associated with the ASSuT isolates (n = 24; 38%), which contained blaTEM, strA-strB, tet(B) and sul2. ST19 was more likely to be associated with the ACSSuT phenotype and contained blaTEM, floR, strA-strB, sul2 and tet(A) or blaPSE-1, floR, aadA2, sul1 and tet(G). CONCLUSIONS: The prevalence of Salmonella 4,[5],12:i:- has significantly increased from 2003 to 2010 and it is now the fifth most common serotype reported in Canada causing human disease. Similar antimicrobial resistance patterns, phage types and STs have been observed in Europe.

Multi-species biofilms defined from drinking water microorganisms provide increased protection against chlorine disinfection.

A model biofilm, formed of multiple species from environmental drinking water, including opportunistic pathogens, was created to explore the tolerance of multi-species biofilms to chlorine levels typical of water-distribution systems. All species, when grown planktonically, were killed by concentrations of chlorine within the World Health Organization guidelines (0.2-5.0 mg l(-1)). Higher concentrations (1.6-40-fold) of chlorine were required to eradicate biofilm populations of these strains, ~70% of biofilms tested were not eradicated by 5.0 mg l(-1) chlorine. Pathogenic bacteria within the model multi-species biofilms had an even more substantial increase in chlorine tolerance; on average ~700-1100 mg l(-1) chlorine was required to eliminate pathogens from the biofilm, 50-300-fold higher than for biofilms comprising single species. Confocal laser scanning microscopy of biofilms showed distinct 3D structures and multiple cell morphologies and arrangements. Overall, this study showed a substantial increase in the chlorine tolerance of individual species with co-colonization in a multi-species biofilm that was far beyond that expected as a result of biofilm growth on its own.

Antimicrobial-resistant Escherichia coli in public beach waters in Quebec.

INTRODUCTION: Human exposure to antimicrobial-resistant bacteria may result in the transfer of resistance to commensal or pathogenic microbes present in the gastrointestinal tract, which may lead to severe health consequences and difficulties in treatment of future bacterial infections. It was hypothesized that the recreational waters from beaches represent a source of antimicrobial-resistant Escherichia coli for people engaging in water activities. OBJECTIVE: To describe the occurrence of antimicrobial-resistant E coli in the recreational waters of beaches in southern Quebec. METHODS: Sampling occurred over two summers; in 2004, 674 water samples were taken from 201 beaches, and in 2005, 628 water samples were taken from 177 beaches. The minimum inhibitory concentrations of the antimicrobial-resistant E coli isolates against a panel of 16 antimicrobials were determined using microbroth dilution. RESULTS: For 2004 and 2005, respectively, 28% and 38% of beaches sampled had at least one water sample contaminated by E coli resistant to one or more antimicrobials, and more than 10% of the resistant isolates were resistant to at least one antimicrobial of clinical importance for human medicine. The three antimicrobials with the highest frequency of resistance were tetracycline, ampicillin and sulfamethoxazole. DISCUSSION: The recreational waters of these beaches represent a potential source of antimicrobial-resistant bacteria for people engaging in water activities. Investigations relating the significance of these findings to public health should be pursued.

INTRODUCTION: L'exposition humaine à des bactéries résistant aux antimicrobiens peut provoquer le transfert de la résistance à des microbes commensaux ou pathogènes présents dans le tube digestif, ce qui peut avoir de graves conséquences sur la santé et compliquer le traitement de futures infections bactériennes. On a soulevé l'hypothèse que les eaux de baignade des plages représentent une source d'infection à l'Escherichia coli résistant aux antimicrobiens pour les personnes qui s'adonnent à des activités aquatiques. La présente étude visait principalement à décrire l'occurrence d'E coli résistant aux antimicrobiens dans les eaux de baignade du sud du Québec. MÉTHODOLOGIE: Les chercheurs ont procédé à l'échantillonnage sur deux étés. En 2004, ils ont prélevé 674 échantillons d'eau sur 201 plages, et en 2005, 628 échantillons d'eau sur 177 plages. Ils ont établi les concentrations inhibitrices minimales des isolats d'E coli résistant aux antimicrobiens par rapport à un groupe de 16 antimicrobiens au moyen d'une dilution en bouillon. RÉSULTATS: En 2004 et en 2005, respectivement, 28 % et 38 % des plages échantillonnées comptaient au moins un échantillon d'eau contaminée par l'E coli résistant à au moins un antimicrobien, et plus de 10 % de ces isolats résistaient à un moins un antimicrobien d'importance clinique en médecine humaine. La tétracycline, l'ampicilline et le sulfaméthoxazole étaient les trois antimicrobiens les plus touchés par la résistance. EXPOSÉ: Les eaux de baignade de ces plages représentent une source potentielle de bactéries résistant aux antimicrobiens pour les personnes qui s'adonnent à des activités aquatiques. Il faudrait poursuivre les recherches sur la signification de ces observations en matière de santé publique.

Distribution and characterization of ampicillin- and tetracycline-resistant Escherichia coli from feedlot cattle fed subtherapeutic antimicrobials.

BACKGROUND: Feedlot cattle in North America are routinely fed subtherapeutic levels of antimicrobials to prevent disease and improve the efficiency of growth. This practice has been shown to promote antimicrobial resistance (AMR) in subpopulations of intestinal microflora including Escherichia coli. To date, studies of AMR in feedlot production settings have rarely employed selective isolation, therefore yielding too few AMR isolates to enable characterization of the emergence and nature of AMR in E. coli as an indicator bacterium. E. coli isolates (n = 531) were recovered from 140 cattle that were housed (10 animals/pen) in 14 pens and received no dietary antimicrobials (control--5 pens, CON), or were intermittently administered subtherapeutic levels of chlortetracycline (5 pens-T), chlortetracycline + sulfamethazine (4 pens-TS), or virginiamycin (5 pens-V) for two separate periods over a 9-month feeding period. Phenotype and genotype of the isolates were determined by susceptibility testing and pulsed field gel electrophoresis and distribution of characterized isolates among housed cattle reported. It was hypothesized that the feeding of subtherapeutic antibiotics would increase the isolation of distinct genotypes of AMR E. coli from cattle. RESULTS: Overall, patterns of antimicrobial resistance expressed by E. coli isolates did not change among diet groups (CON vs. antibiotic treatments), however; isolates obtained on selective plates (i.e., M(A),M(T)), exhibited multi-resistance to sulfamethoxazole and chloramphenicol more frequently when obtained from TS-fed steers than from other treatments. Antibiograms and PFGE patterns suggested that AMR E. coli were readily transferred among steers within pens. Most M(T) isolates possessed the tet(B) efflux gene (58.2, 53.5, 40.8, and 50.6% of isolates from CON, T, TS, and V steers, respectively) whereas among the M(A) (ampicillin-resistant) isolates, the tem1-like determinant was predominant (occurring in 50, 66.7, 80.3, and 100% of isolates from CON, T, TS, and V steers, respectively). CONCLUSIONS: Factors other than, or in addition to subtherapeutic administration of antibiotics influence the establishment and transmission of AMR E. coli among feedlot cattle.

Determination of the relative economic impact of different molecular-based laboratory algorithms for respiratory viral pathogen detection, including Pandemic (H1N1), using a secure web based platform.

BACKGROUND: During period of crisis, laboratory planners may be faced with a need to make operational and clinical decisions in the face of limited information. To avoid this dilemma, our laboratory utilizes a secure web based platform, Data Integration for Alberta Laboratories (DIAL) to make near real-time decisions.This manuscript utilizes the data collected by DIAL as well as laboratory test cost modeling to identify the relative economic impact of four proposed scenarios of testing for Pandemic H1N1 (2009) and other respiratory viral pathogens. METHODS: Historical data was collected from the two waves of the pandemic using DIAL. Four proposed molecular testing scenarios were generated: A) Luminex respiratory virus panel (RVP) first with/without US centers for Disease Control Influenza A Matrix gene assay (CDC-M), B) CDC-M first with/without RVP, C) RVP only, and D) CDC-M only. Relative cost estimates of different testing algorithm were generated from a review of historical costs in the lab and were based on 2009 Canadian dollars. RESULTS: Scenarios A and B had similar costs when the rate of influenza A was low (< 10%) with higher relative cost in Scenario A with increasing incidence. Scenario A provided more information about mixed respiratory virus infection as compared with Scenario B. CONCLUSIONS: No one approach is applicable to all conditions. Testing costs will vary depending on the test volume, prevalence of influenza A strains, as well as other circulating viruses and a more costly algorithm involving a combination of different tests may be chosen to ensure that tests results are returned to the clinician in a quicker manner. Costing should not be the only consideration for determination of laboratory algorithms.

Laboratory based surveillance of travel-related Shigella sonnei and Shigella flexneri in Alberta from 2002 to 2007.

Between 2002 and 2007, travel related cases of Shigella sonnei and S. flexneri in Alberta, Canada were acquired from Central America, the Indian subcontinent and North America. Of this group, resistance to ciprofloxacin and nalidixic acid was identified in isolates from patients who had travelled to the Indian subcontinent. This study provides a Canadian perspective to a growing body of literature linking ciprofloxacin and nalidixic acid resistance to travel to the Indian subcontinent.Shigella is a common cause of diarrheal illness in North America with a rate of 2.0 per 100,000 in Canada 1 and a rate of 3.2 per 100,000 in the United States 23. Imported cases of Shigella infections have been reported in developed countries following travel to a foreign or developing country 45 and may be impacted by factors including socio-economic factors 6, food distribution networks 5 and microbiologic factors 7. Across multiple geographic regions, high rates of antimicrobial resistance to multiple agents (e.g. sulfonamides, tetracycline, chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole) have limited the choices for empiric antimicrobial therapy required to manage Shigella infections and reduce fecal excretion of the bacteria 8910 with descriptions of shifting species dominance and changes in antimicrobial susceptibility 1011. Generally, Shigella flexneri and Shigella sonnei are the dominant species and are heavily impacted by changes in antimicrobial susceptibility 1213.This study identifies the global regions associated with travel-related cases of S. flexneri and S. sonnei in Alberta, Canada and compares antibiotic resistance patterns of these isolates for 2002 to 2007 inclusive.Specimens collected 2002-2007 (inclusive) from S. flexneri and S. sonnei infections in Alberta, Canada were included for study. Data collected at time of specimen submission included: date of specimen collection, outbreak association if present, travel history and antibiogram (data source-ProvLab Information Systems; Communicable Disease Report at Alberta Health and Wellness). Outbreaks were defined by public health officials as ≥ 2 epidemiologically related cases. Each outbreak was assigned a unique incident number. Repeat isolates received within six months of original case infections were excluded. Only one representative case for each outbreak was included, unless the isolates had different antibiotic susceptibility patterns. Based on travel history the origin of an isolate was grouped into corresponding regions and continents. Regions included in the study represented major travel destinations for individuals living in Canada. Domestic exposures were defined as "travel within North America."

Isolation and detection of Shiga toxin-producing Escherichia coli in clinical stool samples using conventional and molecular methods.

The isolation of Shiga toxin-producing Escherichia coli (STEC) other than serogroup O157 from clinical stool samples is problematic due to the lack of differential phenotypic characteristics from non-pathogenic E. coli. The development of molecular reagents capable of identifying both toxin and serogroup-specific genetic determinants holds promise for a more comprehensive characterization of stool samples and isolation of STEC strains. In this study, 876 stool samples from paediatric patients with gastroenteritis were screened for STEC using a cytotoxicity assay, commercial immunoassay and a conventional PCR targeting Shiga-toxin determinants. In addition, routine culture methods for isolating O157 STEC were also performed. The screening assays identified 45 stools presumptively containing STEC, and using non-differential culture techniques a total of 20 O157 and 22 non-O157 strains were isolated. These included STEC serotypes O157 : H7, O26 : H11, O121 : H19, O26 : NM, O103 : H2, O111 : NM, O115 : H18, O121 : NM, O145 : NM, O177 : NM and O5 : NM. Notably, multiple STEC serotypes were isolated from two clinical stool samples (yielding O157 : H7 and O26 : H11, or O157 : H7 and O103 : H2 isolates). These data were compared to molecular serogroup profiles determined directly from the stool enrichment cultures using a LUX real-time PCR assay targeting the O157 fimbrial gene lpfA, a microsphere suspension array targeting allelic variants of espZ and a gnd-based molecular O-antigen serogrouping method. The genetic profile of individual stool cultures indicated that the espZ microsphere array and lpfA real-time PCR assay could accurately predict the presence and provide preliminary typing for the STEC strains present in clinical samples. The gnd-based molecular serogrouping method provided additional corroborative evidence of serogroup identities. This toolbox of molecular methods provided robust detection capabilities for STEC in clinical stool samples, including co-infection of multiple serogroups.

Characterization of tetracycline- and ampicillin-resistant Escherichia coli isolated from the feces of feedlot cattle over the feeding period.

The objective of this study was to investigate tetracycline and ampicillin resistance in Escherichia coli isolated from the feces of 50 crossbred steers housed in 5 feedlot pens. The steers were not administered antibiotics over a 246-day feeding period. A total of 216 isolates were selected for further characterization. The E. coli isolates were selected on MacConkey agar or on MacConkey agar amended with ampicillin (50 microg/mL) or tetracycline (4 microg/mL). Pulsed-field gel electrophoresis (PFGE) typing (XbaI digestion), screening against 11 antibiotics, and multiplex PCR for 14 tet and 3 beta-lactamase genes were conducted. Prevalence of antimicrobial resistance in E. coli at each sampling day was related both temporally and by pen. Multiplex PCR revealed that tet(B) was most prevalent among tetracycline-resistant isolates, whereas beta-lactamase tem1-like was detected mainly in ampicillin-resistant isolates. Our results suggest that antimicrobial resistance in E. coli populations persists over the duration of the feeding period, even in the absence of in-feed antibiotics. Many of the isolates with the same antibiograms had indistinguishable PFGE patterns. Characterization of the factors that influence the nature of this nonselective resistance could provide important information for consideration in the regulation of in-feed antimicrobials for feedlot cattle.

Escherichia coli O157:H7 lineages in healthy beef and dairy cattle and clinical human cases in Alberta, Canada.

The aim of this study was to examine the prevalence and distribution of Escherichia coli O157:H7 lineage-specific polymorphism assay (LSPA) 6 genotypes from cattle (n = 313) and clinical human (n = 203) isolates from northern and southern Alberta, Canada, to understand possible associations of genotypes with host and geographic location. The majority of cattle isolates (feedlot and dairy) typed as LSPA-6 111111 (72.2%), with proportionately higher LSPA-6 222222 (19.4%) than other LSPA-6 genotypes (10.7%). Clinical human isolates also typed primarily as LSPA-6 111111 (90.1%), but a higher percentage of genotypes (6.8%) other than LSPA-6 222222 (3.1%) was observed. A significantly higher frequency of LSPA-6 111111 in southern Alberta cattle (P < 0.0001) and a significant difference in LSPA-6 genotypes between human versus feedlot cattle from northern Alberta (P < 0.0001) were detected. LSPA-6 211111 genotype was third and second most common in cattle and humans, respectively, and several new LSPA-6 genotypes (n = 19) were also discovered. Despite avoiding over-representation of isolates from specific farms or outbreaks, higher strain diversity among cattle by pulsed-field gel electrophoresis (PFGE; 50 genotypes) in contrast to human (9 PFGE genotypes) isolates was observed. The majority of cattle (74.4%) and human (90.6%) isolates were susceptible to the antimicrobials tested. Within resistant cattle isolates, sulfisoxazole-tetracycline resistance was common (62.5%) and was accounted for by the presence of sul1 and sul2, and tet(A) and tet(B) determinants. An association between LSPA-6 and PFGE genotypes but not between geographic location and PFGE genotype for both hosts was evident.

One-year outcomes and health care utilization in survivors of severe acute respiratory syndrome.

BACKGROUND: Severe Acute Respiratory Syndrome (SARS) became a global epidemic in 2003. Comprehensive information on 1-year outcomes and health care utilization is lacking. Research conducted during the SARS outbreak may help inform research planning for future public health emergencies. The objective of this study was to evaluate the 1-year outcomes in survivors of SARS and their family caregivers. METHOD: The study was prospective and observational. We evaluated 117 SARS survivors from Toronto, Ontario. Patients were interviewed and underwent physical examination, pulmonary function testing, chest radiography, a 6-minute-walk test, quality-of-life measures, and self-report of health care utilization. At 1 year, informal caregivers were identified for a survey on caregiver burden. RESULTS: The enrolled survivors of SARS were young (median age, 42 years), and most were women (67%) and health care workers (65%). At 1 year after hospital discharge, pulmonary function measures were in the normal range, but 18% of patients had a significant reduction in distance walked in 6 minutes. The Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) domains were 0.3 to 1.0 SD below normal at 1 year. Of the patients, 17% had not returned to work by 1 year. Fifty-one patients required 668 visits to psychiatry or psychology practitioners. During the SARS epidemic, informal caregivers reported a decline of 1.6 SD below normal on the mental component score of the SF-36. CONCLUSIONS: Most SARS survivors had good physical recovery from their illness, but some patients and their caregivers reported a significant reduction in mental health 1 year later. Strategies to ameliorate the psychological burden of an epidemic on the patient and family caregiver should be considered as part of future pandemic planning.

Identification of Enteric Viruses in Oral Swabs from Children with Acute Gastroenteritis.

Stool is the diagnostic specimen of choice to identify enteropathogens in pediatric gastroenteritis. However, stool collection is challenging and its diagnostic characteristics in patients with isolated vomiting are unknown. Therefore, we evaluated if oral swabs are a suitable alternative specimen to stools. In total, 738 oral swabs and 577 stool specimens were collected from 738 children with vomiting and/or diarrhea. All specimens were tested by a laboratory-developed quantitative RT-PCR Gastroenteritis Virus Panel; 150 oral swabs and 577 stool specimens were tested by the commercial gastroenteritis pathogen panel. The Gastroenteritis Virus Panel identified adenovirus (n = 38), norovirus (n = 21), and rotavirus (n = 16) commonly in oral swabs. In stool specimens, rotavirus (n = 139), norovirus (n = 86), and adenovirus (n = 69) were detected commonly. Compared with stool specimens, the specificity of oral swabs was 99% (95% CI, 96%-100%); the sensitivity of oral swabs was 18% (95% CI, 14%-22%) for the detection of enteric viruses. The Gastrointestinal Pathogen Panel identified enteric bacteria and parasites in stool but not in oral swabs. Given the lower sensitivity of oral swabs, stool remains a preferable specimen to detect enteric viruses. However, with their high specificity, oral swabs can be considered as a suitable specimen if stool specimens are unavailable. Nevertheless, negative oral swabs require a confirmative test of stool specimens.

Adverse events associated with high-dose ribavirin: evidence from the Toronto outbreak of severe acute respiratory syndrome.

STUDY OBJECTIVES: To distinguish adverse events related to ribavirin therapy from those attributable to severe acute respiratory syndrome (SARS), and to determine the rate of potential ribavirin-related adverse events. DESIGN: Retrospective cohort study. SETTING: Hospitals in Toronto, Ontario, Canada. PATIENTS: A cohort of 306 patients with confirmed or probable SARS, 183 of whom received ribavirin and 123 of whom did not, between February 23, 2003, and July 1, 2003. Of the 183 treated patients, 155 (85%) received very high-dose ribavirin; the other 28 treated patients received lower-dose regimens. MEASUREMENTS AND MAIN RESULTS: Data on all patients with SARS admitted to hospitals in Toronto were abstracted from charts and electronic databases onto a standardized form by trained research nurses. Logistic regression was used to evaluate the association between ribavirin use and each adverse event (progressive anemia, hypomagnesemia, hypocalcemia, bradycardia, transaminitis, and hyperamylasemia) after adjusting for SARS-related prognostic factors and corticosteroid use. In the primary logistic regression analysis, ribavirin use was strongly associated with anemia (odds ratio [OR] 3.0, 99% confidence interval [CI] 1.5-6.1, p<0.0001), hypomagnesemia (OR 21, 99% CI 5.8-73, p<0.0001), and bradycardia (OR 2.3, 99% CI 1.0-5.1, p=0.007). Hypocalcemia, transaminitis, and hyperamylasemia were not associated with ribavirin use. The risk of anemia, hypomagnesemia, and bradycardia attributable to ribavirin use was 27%, 45%, and 17%, respectively. CONCLUSIONS: High-dose ribavirin is associated with a high rate of adverse events. The use of high-dose ribavirin is appropriate only for the treatment of infectious diseases for which ribavirin has proven clinical efficacy, or in the context of a clinical trial. Ribavirin should not be used empirically for the treatment of viral syndromes of unknown origin.