Scaling Up Citizen Workshops in Public Libraries to Disseminate and Discuss Primary Care Research Results: Quasi-Experimental Study.

BACKGROUND: Little is known about engaging patients and stakeholders in the process of scaling up effective knowledge translation interventions targeting the public. OBJECTIVE: Using an integrated knowledge translation approach, we aimed to scale up and evaluate an effective pilot program to disseminate research results in public libraries. METHODS: We conducted a scaling-up study targeting the public. On the basis of our successful pilot project, we codeveloped and implemented a large-scale program of free citizen workshops in public libraries, in a close research partnership with stakeholders and patient representatives. Citizen workshops, each facilitated by 1 participating physician and 1 science communicator, consisted of a 45-minute computer-assisted presentation and a 45-minute open exchange. The intervention outcome was knowledge gained. The scale-up outcomes were satisfaction, appropriateness, coverage, and costs. An evaluation questionnaire was used to collect data of interest. Both quantitative and qualitative analyses were performed. RESULTS: The workshop theme chosen by the patient and stakeholder representatives was the high prevalence of medication overuse among people aged ≥65 years. From April to May 2019, 26 workshops were conducted in 25 public libraries reaching 362 people. The mean age of participants was 64.8 (SD 12.5) years. In total, 18 participating physicians and 6 science communicators facilitated the workshops. Participants reported significant knowledge gain (mean difference 2.1, 95% CI 2.0-2.2; P<.001). The median score for overall public satisfaction was 9 out of 10 (IQR 8-10). The public participants globally rated the workshops as having a high level of appropriateness. Coverage was 92% (25/27) of the total number of public libraries targeted. Costs were CAD $6051.84 (US $4519.69) for workshop design and CAD $22,935.41 (US $17,128.85) for scaling them up. CONCLUSIONS: This project successfully established a large-scale and successful implementation science or knowledge translation bridge among researchers, clinicians, and citizens via public libraries. This study provides a model for a dissemination practice that benefits the public by both engaging them in the dissemination process and targeting them directly.

Transcriptional analysis of antibiotic resistance and virulence genes in multiresistant hospital-acquired MRSA.

The staphylococcal chromosome cassette mec cannot solely explain the multiresistance phenotype or the relatively mild virulence profile of hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA). This study reports that several multiresistant HA-MRSA strains differently expressed genes that may support antibiotic resistance, modify the bacterial surface and influence the pathogenic process. Genes encoding efflux pumps (norA, arsB, emrB) and the macrolide resistance gene ermA were found to be commonly expressed by HA-MRSA strains, but not in the archetypal MRSA strain COL. At equivalent cell density, the agr system was considerably less activated in all MRSA strains (including COL) in comparison with a prototypic antibiotic-susceptible strain. These results are in contrast to those observed in recent community-acquired MRSA isolates and may partly explain how multiresistant HA-MRSA persist in the hospital setting.

Binding of ceftaroline to penicillin-binding proteins of Staphylococcus aureus and Streptococcus pneumoniae.

OBJECTIVES: This study evaluated the affinity of ceftaroline and comparator beta-lactams for penicillin-binding proteins (PBPs) of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA) and Streptococcus pneumoniae with varying susceptibility to penicillin. Ceftaroline is currently in Phase 3 development for the treatment of complicated skin and skin structure infections and community-acquired pneumonia, including infections caused by MRSA and multidrug-resistant S. pneumoniae. METHODS: Binding affinities (IC(50)s) of ceftaroline, ceftriaxone, oxacillin and penicillin G for PBPs were measured in a competition assay by adding various concentrations of the test drugs to membranes or whole cells. PBPs were labelled using the fluorescent reporter molecule Bocillin FL. RESULTS: Overall, ceftaroline exhibited greater binding affinity for the range of PBPs tested, as compared with comparator beta-lactams. The high affinity of ceftaroline for PBPs 1-3 of MSSA and PBP2a of MRSA correlates well with its efficacy against these organisms, as determined by MIC. Similarly, efficient binding of ceftaroline to key S. pneumoniae PBPs, such as PBP2x/2a/2b, taken together, correlates well with its low MICs for penicillin-resistant isolates of S. pneumoniae. CONCLUSIONS: The high affinities of ceftaroline for MRSA PBP2a, MSSA PBPs 1-3 and S. pneumoniae PBP2x/2a/2b support the potential efficacy of ceftaroline in the treatment of infections caused by MRSA and S. pneumoniae.

Relative cytotoxicity of Escherichia coli O157:H7 isolates from beef cattle and humans.

Differences and similarities between Escherichia coli O157:H7 isolates from beef cattle and those from sporadic human outbreaks are not fully elucidated. Here, we compared 44 O157:H7 isolates of bovine and human origins (22 isolates of each) to better understand their cytotoxic potential. The Shiga toxin genes stx1, stx2, or both were detected in the 44 isolates, and all elicited Vero cell cytotoxicity. The greatest cytotoxicity was caused by bovine isolates having only stx2 and which represented the majority of such isolates (81.8%). However, no correlation was found between the level of stx gene transcription and cytotoxicity. All human and bovine isolates possessed variant type stx2 and stx2c, respectively, as determined by PCR-restriction fragment length polymorphism. Isolates harboring both stx1 and stx2 genes were much more frequent in human isolates (86.4%). The combination stx1-stx2c found in only four bovine isolates was less cytotoxic. It is clear that cytotoxicity alone cannot account for the apparent inability of O157:H7 bovine isolates to cause diseases in humans. We have found that stx1-stx2-containing or stx1-stx2c-containing isolates were less cytotoxic than several bovine isolates having only stx2c, suggesting that the stx gene combination or other virulence genes in specific genetic lineages may affect the disease outcome.

Characterization of a Staphylococcus aureus small colony variant (SCV) associated with persistent bovine mastitis.

Staphylococcus aureus is a common cause of bovine mastitis and foodborne and other diseases in humans. This study tested the hypothesis that small colony variants (SCVs) of S. aureus are implicated in chronic bovine mastitis. Six S. aureus isolates from foremilk samples from 11 chronically infected cows were investigated. Five isolates had typical morphology and were hemolytic and coagulase positive; one was a heterogeneous population of typical and SCV phenotype (tiny nonhemolytic colonies). In the presence of gentamicin, three of the previously typical S. aureus developed SCVs that were confirmed as S. aureus by biochemical and genetic analyses; these SCVs reverted to the typical form on antibiotic-free medium. The SCV isolate (Heba3231) from the heterogeneous population had a slow growth rate and prolonged lag phase and did not revert during 10 h of incubation. Transcriptional analysis showed that SCV Heba3231 had reduced expression of agr, hla, and coa and increased expression of indicators of fermentation pathways compared to the parent strain. Invasion of and persistence in a primary culture of bovine aortic endothelial cells (BAEC) showed that SCV Heba3231 had minimal deleterious effects, whereas the parent strain or the Newbould 305 strain caused severe damage. Recovery of the parent strain from BAEC yielded a mixture of the parent and SCV phenotypes. This study reports for the first time the isolation of S. aureus SCV from persistent bovine mastitis and suggests that SCV may be an important contributor to the prolonged survival of S. aureus in some cases of mastitis.

Detection of virulence-associated genes in Escherichia coli O157 and non-O157 isolates from beef cattle, humans, and chickens.

Food-producing animals can be reservoirs of pathogenic Escherichia coli strains that can induce diseases in animals or humans. Contamination of food by E. coli O157:H7 raises immediate concerns about public health, although it is not clear whether all E. coli O157 isolates of animal origin are equally harmful to humans. Inversely, the pathogenic potential of atypical E. coli O157 isolates and several non-O157 serotypes often is ignored. We used a DNA microarray capable of detecting a subset of 346 genes to compare the virulence-associated genes present in eight E. coli O157 isolates from human cases, 14 antibiotic-resistant and/or hypermutable E. coli O157 isolates from beef cattle, and four antibiotic-resistant, sorbitol-negative, non-O157 E. coli isolates from healthy broiler chickens. Hybridization on arrays (HOA) revealed that O157 isolates from beef cattle and humans were genetically distinct, although they possessed most of the same subset of virulence genes. HOA allowed discrimination between hypermutable and antibiotic-resistant O157 isolates from beef cattle based on hybridization results for the stx2 and ycgG genes (hypermutable) or ymfL, stx1, stx2, and hlyE(avian) genes (resistant). However, the absence of hybridization to gene yfdR characterized human isolates. HOA also revealed that an atypical sorbitol-fermenting bovine O157 isolate lacked some genes of the type 3 secretion system, plasmid pO157, and the stx1 and stx2 genes. This isolate had a particular pathotype (eaeA(beta) tir(alpha) espA(alpha) espB(alpha) espD(alpha)) not found in typical E. coli O157:H7. HOA revealed that some non-O157 E. coli isolates from healthy chickens carried genes responsible for salmochelin- and yersiniabactin-mediated iron uptake generally associated with pathogenic strains.

Transcriptional modulation of some Staphylococcus aureus iron-regulated genes during growth in vitro and in a tissue cage model in vivo.

Staphylococcus aureus can proliferate in iron-limited environments such as the mammalian host. The transcriptional profiles of 460 genes (iron-regulated, putative Fur-regulated, membrane transport, pathogenesis) obtained for S. aureus grown in iron-restricted environments in vitro and in vivo were compared in order to identify new iron-regulated genes and to evaluate their potential as possible therapeutic targets in vivo. Iron deprivation was created in vitro by 2,2-dipyridyl, and in vivo, S. aureus was grown in tissue cages implanted in mice. Bacterial RNA was obtained from each growth condition and cDNA probes were co-hybridized on DNA arrays. Thirty-six upregulated and 11 downregulated genes were commonly modulated in animals and in the low-iron medium. Real-time PCR confirmed the iron-dependent modulation of four novel genes (SACOL0161, 2170, 2369, 2431) with a Fur box motif. Some genes expressed in the dipyridyl medium were not expressed in vivo (e.g., copA, frpA, SACOL1045). Downregulated genes included an iron-storage protein gene and genes of the succinate dehydrogenase complex, reminiscent of a small RNA-dependent regulation thus far only demonstrated in Gram-negative bacteria. The expression of iron-regulated genes in distinct low-iron environments provided insight into their relative importance in vitro and in vivo and their usefulness for vaccine and drug development.

Transcription of virulence factors in Staphylococcus aureus small-colony variants isolated from cystic fibrosis patients is influenced by SigB.

Staphylococcus aureus small-colony variants (SCVs) are believed to account in part for the persistence of S. aureus during chronic infections. Little is understood about the gene expression profile that may explain the phenotype and distinguish SCVs from prototype S. aureus strains. In this study, DNA array transcriptional profiles of clinical SCVs isolated from the airways of cystic fibrosis patients were obtained and compared to those obtained from a laboratory-derived SCV strain (i.e., a respiratory-deficient hemB mutant) and prototype S. aureus strains. The genes commonly up-regulated in both hemB and clinical SCVs were found to be implicated in fermentation and glycolysis pathways. The well-known virulence regulator agr was not activated in SCVs, and such strains had low levels of alpha-toxin (hla) gene expression. Clinical SCVs also had a transcriptional signature of their own. Of striking interest is that many genes, most of them under the positive control of the alternate sigma factor SigB, were specifically up-regulated and differed in that way from that seen in prototype S. aureus and the hemB mutant. Since SigB influences up-regulation of adhesin type genes while indirectly down-regulating exoproteins and toxins, we evaluated the internalization and persistence of SCVs in mammalian cells. Results showed that clinical SCVs persisted much more efficiently in cells than the hemB and prototype strains and that a sigB mutant was a poor persister. Thus, it appears that the agr locus plays a minor role in the regulation of the virulon of SCVs, unlike SigB, which may have a key role in intracellular persistence.