A province-level risk factor analysis of fluoroquinolone consumption patterns in Canada (2000-06).

OBJECTIVES: To assess potential risk factors among socioeconomic variables and the rate of influenza for the use of different fluoroquinolone antimicrobials in Canada, and to evaluate modelling fluoroquinolone-use data by two different outcome measures. METHODS: Fluoroquinolone use was described monthly from 2000 to 2006 by two outcome measurements: defined daily doses and prescription counts. Multivariable linear and negative binomial models were produced with socioeconomic and influenza rate data. RESULTS: Significant socioeconomic predictors varied among the individual fluoroquinolone models, which may reflect the range of infections that are treated with fluoroquinolones. However, socioeconomic variables within the ciprofloxacin and levofloxacin models were similar, and indicated that use was highest in advantaged populations, depending on the measures being assessed. The rate of influenza was a significant predictor within models describing levofloxacin use and the defined daily dose model for ciprofloxacin use, after accounting for season. Influenza significantly interacted with the education variable in the levofloxacin defined daily dose model. CONCLUSIONS: Significant associations between levofloxacin use and influenza rates, after accounting for season, may suggest that levofloxacin was used to treat secondary bacterial infections or was prescribed inappropriately for seasonal viral respiratory tract infections. Yearly patterns of ciprofloxacin use show that prescribing practices changed; more ciprofloxacin prescriptions were dispensed towards the end of the study period, but for smaller doses or shorter treatment times. Associations with socioeconomic variables suggest that the fluoroquinolones ciprofloxacin and levofloxacin were more likely to be used in advantaged populations, probably due to the high cost of fluoroquinolone antimicrobials in comparison to the penicillin and macrolide groups.

Canadian province-level risk factor analysis of macrolide consumption patterns (2000-2006).

OBJECTIVES: To assess provincial-level predictors among socioeconomic and influenza rate data for the use of different macrolide antimicrobials in Canada from 2000 to 2006. METHODS: Multivariable models were developed to describe macrolide defined daily doses per capita. RESULTS: Use was highest during October to March for all macrolides. Investigated yearly and provincial patterns differed considerably among the macrolide agents. Associations with socioeconomic variables were similar between clarithromycin and erythromycin, while azithromycin consumption showed some differences in its association with these variables. Consistently, the rate of influenza was significantly associated with increased macrolide use. The influenza rate interacted with socioeconomic variables in some models; as the influenza rate increased, the greatest increase in demand for macrolides occurred in populations with high percentages of low-income individuals, high unemployment levels and low percentages of individuals with bachelor's degrees. CONCLUSIONS: The impact of associations among macrolide consumption, influenza and socioeconomic factors may reflect inappropriate use of these agents to treat viral infections and/or prescribing for secondary infections, and knowledge of the virus versus bacteria problem and accessibility of healthcare. Further research surrounding differences in access to antimicrobial prescriptions and treatment options between advantaged and disadvantaged populations is suggested to further understand the dynamics of antimicrobial use in Canada.

The effect of transposon Pokey insertions on sequence variation in the 28S rRNA gene of Daphnia pulex.

The goal of this study was to determine the impact of breeding system and the presence of the transposon Pokey on intraindividual variation in 28S rRNA genes. We PCR-amplified, cloned, and sequenced 1000 nucleotides downstream of the Pokey insertion site in genes with and without insertions from 10 obligately and 10 cyclically parthenogenetic isolates of Daphnia pulex. Variation among genes with Pokey insertions was higher than variation among genes without insertions in both cyclic and obligate isolates. Although the differences were not quite significant (p = 0.06 in both cases), the results suggest that Pokey insertions are likely to inhibit the homogenization of their host genes to some extent. We also observed that the complement of 28S rRNA alleles differed between genes with and without inserts in some isolates, suggesting that a particular inserted gene can persist for substantial periods of time and even spread within the rDNA array, despite the fact that insertions are deleterious. This apparently contradictory pattern can be explained if homogenization of rRNA genes occurs primarily by gene conversion, but copies with Pokey inserts can occasionally increase in frequency within arrays owing to unequal crossing over events that do not originate in the inserted genes themselves.