Deciphering the Multifactorial Nature of Acinetobacter baumannii Pathogenicity

Background: Acinetobacter baumannii is an emerging bacterial pathogen that causes a broad array of infections, particularly in hospitalized patients. Many studies have focused on the epidemiology and antibiotic resistance of A. baumannii, but little is currently known with respect to its virulence potential. Methodology/Principal Findings: The aim of this work was to analyze a number of virulence-related traits of four A. baumannii strains of different origin and clinical impact for which complete genome sequences were available, in order to tentatively identify novel determinants of A. baumannii pathogenicity. Clinical strains showed comparable virulence in the Galleria mellonella model of infection, irrespective of their status as outbreak or sporadic strains, whereas a non-human isolate was avirulent. A combined approach of genomic and phenotypic analyses led to the identification of several virulence factors, including exoproducts with hemolytic, phospholipase, protease and iron-chelating activities, as well as a number of multifactorial phenotypes, such as biofilm formation, surface motility and stress resistance, which were differentially expressed and could play a role in A. baumannii pathogenicity. Conclusion/Significance: This work provides evidence of the multifactorial nature of A. baumannii virulence. While A. baumannii clinical isolates could represent a selected population of strains adapted to infect the human host, subpopulations of highly genotypically and phenotypically diverse A. baumannii strains may exist outside the hospita

Acinetobacter baumannii Secretes Cytotoxic Outer Membrane Protein A via Outer Membrane Vesicles

Acinetobacter baumannii is an important nosocomial pathogen that causes a high morbidity and mortality rate in infected patients, but pathogenic mechanisms of this microorganism regarding the secretion and delivery of virulence factors to host cells have not been characterized. Gram-negative bacteria naturally secrete outer membrane vesicles (OMVs) that play a role in the delivery of virulence factors to host cells. A. baumannii has been shown to secrete OMVs when cultured in vitro, but the role of OMVs in A. baumannii pathogenesis is not well elucidated. In the present study, we evaluated the secretion and delivery of virulence factors of A. baumannii to host cells via the OMVs and assessed the cytotoxic activity of outer membrane protein A (AbOmpA) packaged in the OMVs. A. baumannii ATCC 19606T secreted OMVs during in vivo infection as well as in vitro cultures. Potential virulence factors, including AbOmpA and tissue-degrading enzymes, were associated with A. baumannii OMVs. A. baumannii OMVs interacted with lipid rafts in the plasma membranes and then delivered virulence factors to host cells. The OMVs from A. baumannii ATCC 19606T induced apoptosis of host cells, whereas this effect was not detected in the OMVs from the ΔompA mutant, thereby reflecting AbOmpA-dependent host cell death. The N-terminal region of AbOmpA22-170 was responsible for host cell death. In conclusion, the OMV-mediated delivery of virulence factors to host cells may well contribute to pathogenesis during A. baumannii infection

I ♥ U: Attachment Style and Gender as Predictors of Deception in Online and Offline Dating

Online dating is becoming an increasingly used method for meeting significant others. This study had two central goals. The first goal was to explore the factors that contribute to deception used to attract a romantic partner online. The second aim was to discover the reasons that people with different attachment styles might lie as well as their justifications and interpretations for those lies. Male and female single college undergraduates (N = 208), who had previously completed an attachment style measure via an online screening, were asked to complete an online dating profile and an email to a potential dating partner. Participants reviewed these correspondences and noted any inaccuracies. They also completed a questionnaire related to lying in romantic relationships. It was hypothesized that both attachment style and gender would affect lying behavior. For online dating, results indicated that women told more self-oriented and subtle lies than men, and that high attachment avoidance and anxiety predicted greater lying behavior for participants with relationship experience. Offline, attachment predicted the motivations, justifications, and acceptability of lying to romantic partners. Implications related to online dating and attachment processes in relational deception are discussed

Extinctions and threats to avifaunas on oceanic islands: Tests of influences of human populations and the filter effect Extinctions and Threats to Avifaunas on Oceanic Islands: 1 tests of influences of human populations and the filter effect 2 3 Extinctio

Extinctions and threats of extinctions in avifaunas on oceanic islands appear to be influenced by several island characteristics and introduced mammalian predators. These predators may have caused a "filter effect"; low numbers of threatened avian species on some islands might be due to high rates of past extinctions. Using path analysis, we examined these factors and the influence of human population size (as an indicator of human activity) on the number of species extinctions and threatened bird species on islands. Human population size had substantial influences on the number of extinctions (standardized partial regression coefficient ρ = 0.315, N = 172, P = 0.0005) but not on the number of threatened species on oceanic islands (ρ = -0.061, P = 0.43), independent of the number of introductions of predator species. The number of extinctions on islands produced a significant filter effect (viz., had a negative impact; ρ = -0.186, P = 0.003) on the number of currently threatened species. The activities of human populations, including mammalian predators they introduced, have likely resulted in a greater number of bird extinctions on these islands, and producing a significant filter effect, wherein islands with larger human populations now have fewer threatened species. Abstract. Extinctions and threats of extinctions in avifaunas on oceanic islands appear to be influenced by several island characteristics and introduced mammalian predators. These predators may have caused a "filter effect"; low numbers of threatened avian species on some islands might be due to high rates of past extinctions. Using path analysis, we examined these factors and the influence of human population size (as an indicator of human activity) on the number of species extinctions and threatened bird species on islands. Human population size had substantial influences on the number of extinctions (standardized partial regression coefficient ρ = 0.315, N = 172, P = 0.0005) but not on the number of threatened species on oceanic islands (ρ = -0.061, P = 0.43), independent of the number of introductions of predator species. The number of extinctions on islands produced a significant filter effect (viz., had a negative impact; ρ = -0.186, P = 0.003) on the number of currently threatened species. The activities of human populations, including mammalian predators they introduced, have likely resulted in a greater number of bird extinctions on these islands, and producing a significant filter effect, wherein islands with larger human populations now have fewer threatened species

Effect of botulinum toxin pretreatment on laser resurfacing results: a prospective, randomized, blinded trial.

BACKGROUND: Facial laser resurfacing and chemodenervation with botulinum toxin type A are used independently as means of nonsurgical facial rejuvenation. Recent reports in the literature have described combining these 2 therapies, claiming improved and longer-lasting laser resurfacing results. To date, no scientific investigation has been undertaken to prove or disprove this theory. DESIGN: Institutional review board-approved, prospective, randomized, blinded study at university-affiliated outpatient cosmetic surgery offices. INTERVENTION: Patients had one side of their face injected, at specific anatomic subsites (crow\u27s feet, horizontal forehead furrows, and glabellar frown lines), with botulinum toxin 1 week before laser resurfacing. After receiving an injection, patients underwent cutaneous laser exfoliation on both sides of the face with either a carbon dioxide or an erbium dual-mode laser. MAIN OUTCOME MEASURES: Patients\u27 injected (experimental) and noninjected (control) sides were compared after laser resurfacing. Follow-up was documented at 6 weeks, 3 months, and 6 months after laser resurfacing. Subjective evaluation, based on a visual analog scale, was performed in person by a blinded observer. Furthermore, a blinded panel of 3 expert judges (1 facial plastic surgeon, 1 oculoplastic surgeon, and 1 cosmetic dermatologist) graded 35-mm photographs taken during postoperative follow-up visits. RESULTS: Ten female patients were enrolled in the study. A 2-tailed t test showed that all sites that were pretreated with botulinum toxin showed statistically significant improvement (P\u3c or =.05) over the nontreated side, with the crow\u27s feet region showing the greatest improvement. Comparing results between the carbon dioxide and erbium lasers did not result in any statistically significant differences. CONCLUSIONS: Hyperdynamic facial lines, pretreated with botulinum toxin before laser resurfacing, heal in a smoother rhytid-diminished fashion. These results were clinically most significant in the crow\u27s feet region. We recommend pretreatment of movement-associated rhytides with botulinum toxin before laser resurfacing. For optimum results, we further recommend continued maintenance therapy with botulinum toxin postoperatively