SUMMARYA virulent strain of the obligate intracellular bacterium Wolbachia pipientis that shortens insect lifespan has recently been transinfected into the primary mosquito vector of dengue virus, Aedes aegypti L. The microbe's ability to shorten lifespan and spread through host populations under the action of cytoplasmic incompatibility means it has the potential to be used as a biocontrol agent to reduce dengue virus transmission. Wolbachia is present in many host tissues and may have local effects on diverse biological processes. In other insects, Wolbachia infections have been shown to alter locomotor activity and response time to food cues. In mosquitoes, locomotor performance relates to the location of mates, human hosts, resting sites and oviposition sites. We have therefore examined the effect of the virulent, life-shortening Wolbachia strain wMelPop on the locomotion of Ae. aegypti as they age and as the pathogenicity of the infection increases. In parallel experiments we also examined CO 2 production as a proxy for metabolic rate, to investigate a potential mechanistic explanation for any changes in locomotion. Contrary to expectation, we found that the infection increased activity and metabolic rate and that these effects were relatively consistent over the insect's lifespan. The results do not fit a standard model of bacterial pathogenesis in insects, and instead may reveal additional physiological changes induced by infection, such as either increased hunger or defects in the nervous system.

BackgroundMutations that cause learning and memory defects in Drosophila melanogaster have been found to also compromise visual responsiveness and attention. A better understanding of attention-like defects in such Drosophila mutants therefore requires a more detailed characterization of visual responsiveness across a range of visual parameters.Methodology/Principal FindingsWe designed an automated behavioral paradigm for efficiently dissecting visual responsiveness in Drosophila. Populations of flies walk through multiplexed serial choice mazes while being exposed to moving visuals displayed on computer monitors, and infra-red fly counters at the end of each maze automatically score the responsiveness of a strain. To test our new design, we performed a detailed comparison between wild-type flies and a learning and memory mutant, dunce 1. We first confirmed that the learning mutant dunce 1 displays increased responsiveness to a black/green moving grating compared to wild type in this new design. We then extended this result to explore responses to a wide range of psychophysical parameters for moving gratings (e.g., luminosity, contrast, spatial frequency, velocity) as well as to a different stimulus, moving dots. Finally, we combined these visuals (gratings versus dots) in competition to investigate how dunce 1 and wild-type flies respond to more complex and conflicting motion effects.Conclusions/SignificanceWe found that dunce 1 responds more strongly than wild type to high contrast and highly structured motion. This effect was found for simple gratings, dots, and combinations of both stimuli presented in competition.

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Background Pseudomonas aeruginosa isolates from sputum cultures do not always require treatment, often representing chronic airways colonization. By releasing sputum P. aeruginosa antimicrobial susceptibility results, only after specific phone request by treating doctors, we aimed to reduce the use of ciprofloxacin without compromising clinical outcomes.MethodsFrom February 26, 2015, antimicrobial susceptibility results for P. aeruginosa in sputum were routinely suppressed except for immunosuppressed, Intensive Care Unit, cystic fibrosis, or bronchiectasis patients. A database search of the Wollongong Hospital Microbiology laboratory information system identified 108 patients with susceptibility results suppressed (February 26, 2015–February 25, 2017), compared with 108 patients where antimicrobial susceptibility results were routinely reported (February 26, 2013–February 25, 2015). Data collected included age, sex, residency, admission date and diagnosis, comorbidities, allergy, empirical and definitive antibiotic treatment, date of sputum culture, resistance patterns of P. aeruginosa, ciprofloxacin usage, antimicrobial stewardship interventions, length of stay, inpatient mortality, and readmission within 30 days.ResultsThe prevalence of P. aeruginosa in sputum cultures was 11% (1,252/11,388). Patient characteristics were comparable in the two groups. Ciprofloxacin use was significantly reduced postintervention [26.9% (29/108) vs. 39.8% (43/108); P = 0.043] as well as Guidance MS approvals [9.03% (87/963) vs. 17.72% (188/1,061); P = 0.000001]. Interrupted time series analysis of this intervention was not associated with a significant change in the rates of ciprofloxacin use. Rates of ciprofloxacin resistance were lower postintervention [2.8% (3/108) vs. 16.7% (18/108); P = 0.0006], reaffirmed by SQL database search of the OMNI-Client [9.30% (32/343) vs. 15.00% (60/399); P = 0.0187]. Ciprofloxacin usage against resistance over time There was no difference in length of stay, 30-day readmission, and mortality.ConclusionThis study offers a successful model of collaboration between the microbiology laboratory and antimicrobial stewardship activity. It showed a reduction in the use of ciprofloxacin with possible influence on P. aeruginosa resistance rates, without affecting patient outcomes.Disclosures All authors: No reported disclosures.