Using Principal Component Analysis to Identify Priority Neighbourhoods for Health Services Delivery by Ranking Socioeconomic Status.

Objectives. Socioeconomic status (SES) is a comprehensive indicator of health status and is useful in area-level health research and informing public health resource allocation. Principal component analysis (PCA) is a useful tool for developing SES indices to identify area-level disparities in SES within communities. While SES research in Canada has relied on census data, the voluntary nature of the 2011 National Household Survey challenges the validity of its data, especially income variables. This study sought to determine the appropriateness of replacing census income information with tax filer data in neighbourhood SES index development. Methods. Census and taxfiler data for Guelph, Ontario were retrieved for the years 2005, 2006, and 2011. Data were extracted for eleven income and non-income SES variables. PCA was employed to identify significant principal components from each dataset and weights of each contributing variable. Variable-specific factor scores were applied to standardized census and taxfiler data values to produce SES scores. Results. The substitution of taxfiler income variables for census income variables yielded SES score distributions and neighbourhood SES classifications that were similar to SES scores calculated using entirely census variables. Combining taxfiler income variables with census non-income variables also produced clearer SES level distinctions. Internal validation procedures indicated that utilizing multiple principal components produced clearer SES level distinctions than using only the first principal component. Conclusion. Identifying socioeconomic disparities between neighbourhoods is an important step in assessing the level of disadvantage of communities. The ability to replace census income information with taxfiler data to develop SES indices expands the versatility of public health research and planning in Canada, as more data sources can be explored. The apparent usefulness of PCA also contributes to the improvement of SES measurement and calculation methods, and the freedom to input area-specific data allows the present method to be adapted to other locales.

Molecular epidemiology of Campylobacter jejuni human and chicken isolates from two health units.

A study was conducted over a 2-year period in the Perth District and Wellington-Dufferin-Guelph health units in Ontario, with an objective of using comparative genomic fingerprinting (CGF) with a 40-gene assay (CGF40) to investigate the association between human cases of campylobacteriosis and spatially and temporally related Campylobacter isolates from retail chicken. CGF results were available for isolates from 115 human cases and 718 retail chicken samples. These data were combined with CGF results from a large reference database of Campylobacter isolates. Isolates were categorized into types based on >90% CGF40 fingerprint similarity (CGF-90%). CGF-90% types were categorized as chicken associated (CA90) when the proportion of animal isolates in the given type that originated from chicken was at least 80% and was statistically significant. Risk factor data were collected from cases by questionnaire. Urban cases were significantly more likely than rural cases to be CA90 and there were significantly fewer CA90 cases in the second year of the study. Due to the population distribution in Canada and most industrialized countries, the majority of campylobacteriosis cases are urban dwellers. Therefore, the association between urban cases and chicken-associated types of Campylobacter emphasizes the importance of educational and food safety efforts to reduce the impact of Campylobacter from retail chicken on public health. Sources other than chicken may be more important for rural dwellers.

Antimicrobial resistance and antimicrobial use associated with laboratory-confirmed cases of Campylobacter infection in two health units in Ontario.

AIM: A population-based study was conducted over a two-year period in the Perth District (PD) and Wellington-Dufferin-Guelph (WDG) health units in Ontario to document antimicrobial resistance and antimicrobial use associated with clinical cases of laboratory-confirmed campylobacteriosis. METHODS: Etest (bioMérieux SA, France) was used to determine the minimum inhibitory concentration of amoxicillin/clavulanic acid, ampicillin, chloramphenicol, ciprofloxacin (CIP), clindamycin, erythromycin (ERY), gentamicin, nalidixic acid and tetracycline. Data regarding antimicrobial use were collected from 250 cases. RESULTS: Of the 250 cases, 165 (65.7%) reported staying home or being hospitalized due to campylobacteriosis. Fifty-four per cent of cases (135 of 249) reported taking antimicrobials to treat campylobacteriosis. In 115 cases (51.1%), fecal culture results were not used for treatment decisions because they were not available before the initiation of antimicrobial treatment and/or they were not available before the cessation of symptoms. Of the 250 cases, 124 (49.6%) had available Campylobacter isolates, of which 66 (53.2%) were resistant to at least one of the antimicrobials tested. No resistance to ampicillin, chloramphenicol or gentamicin was found in these isolates. Six isolates (4.8%) were resistant to CIP. Two isolates (1.6%) were resistant to ERY; however, no isolates were resistant to both CIP and ERY. CONCLUSION: Prudent use practices should be promoted among physicians to reduce the use of antimicrobials for the treatment of gastroenteritis in general and campylobacteriosis in particular, as well as to minimize the future development of resistance to these antimicrobials in Campylobacter species.

OBJECTIF: Les chercheurs ont mené une étude en population pendant une période de deux ans dans les unités sanitaires du district de Perth et de Wellington-Dufferin-Guelph en Ontario, afin d'étayer la résistance antimicrobienne et l'utilisation d'antimicrobiens associées à des cas cliniques de campylobactériose confirmés en laboratoire. MÉTHODOLOGIE: Les chercheurs ont utilisé l'Etest (bioMérieux SA, France) pour déterminer la concentration inhibitrice minimale d'amoxicilline-acide clavulanique, d'ampicilline, de chloramphénicol, de ciprofloxacine (CIP), de clindamycine, d'érythromycine (ERY), de gentamicine, d'acide nalidixique et de tétracycline. Ils ont colligé les données sur l'utilisation d'antimicrobiens auprès de 250 cas. RÉSULTATS: Sur les 250 cas, 165 (65,74 %) ont déclaré être restés à la maison ou avoir été hospitalisés en raison de leur campylobactériose. Cinquante-quatre pour cent des cas (135 sur 249) ont déclaré avoir pris des antimicrobiens pour traiter leur campylobactériose. Dans 115 cas (51,1 %), les résultats de la coproculture n'ont pas été utilisés pour prendre les décisions thérapeutiques parce qu'ils n'étaient pas disponibles avant l'amorce du traitement antimicrobien ou avant l'arrêt des symptômes. Sur les 250 cas, 124 (49,6 %) disposaient d'isolats du Campylobacter, dont 66 (53,2 %) étaient résistants à au moins un des antimicrobiens testés. Les chercheurs n'ont relevé aucun cas de résistance à l'ampicilline, au chloramphénicol ou à la gentamicine dans ces isolats. Six (4,8 %) étaient résistants à la CIP et deux (1,6 %), à l'ERY, mais aucun n'était résistant à la fois à la CIP et à l'ERY. CONCLUSION: Il faudrait promouvoir des pratiques d'utilisation prudentes chez les médecins pour réduire l'utilisation d'antimicrobiens dans le traitement de la gastroentérite en général et de la campylobactériose en particulier, ainsi que pour limiter le plus possible l'apparition future de résistance à ces antimicrobiens dans les espèces de Campylobacter.

Bayesian spatial methods for small-area injury analysis: a study of geographical variation of falls in older people in the Wellington-Dufferin-Guelph health region of Ontario, Canada.

OBJECTIVES: To examine falls in older people in the Wellington-Dufferin-Guelph (WDG) health region of Ontario, Canada, and to identify areas with excess RR and associated risk factors, particularly those related to private dwellings. METHODS: Cases of hospitalisation following falls among older people in the WDG health region between 2002 and 2006 were geocoded to the dissemination area level and used in the spatial analysis. The falls data and covariates from the 2006 Canadian census were analysed using Poisson log-linear models with (spatial and non-spatial) random effects at the dissemination area level. A Bayesian approach with Markov chain Monte Carlo simulation allowed the spatial random effects models to be fitted. Map decomposition was used to visualise the results. RESULTS: The percentage of occupied private dwellings requiring repairs and median income were significantly associated with falls in older people in the WDG health region. Twenty-six dissemination areas with high RR of falls in older people in the WDG health region were identified. Map decomposition revealed that RR were also driven by unknown factors that have spatial patterns. CONCLUSIONS: This research identified an association between falls in older people and housing conditions; the higher the percentage of dwellings requiring repairs in an area, the higher its risk of falls in older people. Bayesian spatial modelling accounts for measurement errors and unobserved or unknown risk factors that have spatial patterns. The findings have the potential to contribute to future research in reducing falls in older people and generate more interest in using Bayesian spatial modelling approaches in injury and public health research.

Prevalence and antimicrobial resistance in Campylobacter spp. isolated from retail chicken in two health units in Ontario.

Campylobacter is an important enteric pathogen of humans and can cause diarrhea, fever, and abdominal pain. Campylobacter infections have frequently been associated with the handling and consumption of raw and undercooked poultry. Antimicrobial resistance among Campylobacter strains is of concern in the treatment of campylobacteriosis in vulnerable populations. A 2-year multidisciplinary study was conducted in the Perth and Wellington-Dufferin-Guelph public health units in Ontario, Canada, to investigate the prevalence and antimicrobial resistance of Campylobacter spp. in retail chicken. Retail chicken samples were collected from randomly selected stores in these health units. Resulting Campylobacter isolates were tested for susceptibility to amoxicillin-clavulanic acid (AMC), ampicillin (AMP), chloramphenicol (CHL), ciprofloxacin (CIP), clindamycin (CLI), erythromycin (ERY), gentamicin (GEN), nalidixic acid (NAL), tetracycline (TCY), and trimethoprim-sulfamethoxazole (SXT) using the E test. The prevalence of Campylobacter in 1,256 retail chicken samples was 59.6%. Of these positive samples, 9% contained Campylobacter coli, 1% contained Campylobacter lari, and 90% contained Campylobacter jejuni. Of the chicken isolates that were resistant to one or more antimicrobial agents, 301 isolates (40%) were resistant to one agent, 374 (50%) were resistant to two, 39 (5%) were resistant to three, 20 (3%) were resistant to four, and 6 (1%) were resistant to five. Nine isolates (1%) were susceptible to all antimicrobial agents tested. All isolates were susceptible to AMC, CHL, and GEN. Less than 10% of isolates were resistant to NAL, CIP, CLI, ERY, and AMP. Resistance to TCY was common (56%). No isolates had a resistance pattern that included all three antimicrobials important in the treatment of human campylobacteriosis (CIP, ERY, and TCY); however, 24 isolates (3.2%) were resistant to at least two of these antimicrobials.