Carriage of an ACME II variant may have contributed to methicillin-resistant staphylococcus aureus sequence type 239-like strain replacement in Liverpool hospital, Sydney, Australia

Approximately 39% of methicillin-resistant Staphylococcus aureus (MRSA) sequence type 239 (ST239)-like bloodstream isolates from Liverpool Hospital (obtained between 1997 and 2008) carry an arginine catabolic mobile element (ACME). Whole-genome sequencing revealed that an ACME II variant is located between orfX and SCCmec III, and based on pulsed-field gel electrophoresis patterns and temporal relationships of all ST239-like isolates (n = 360), ACME carriage may have contributed to subpulsotype strain replacement

Chromosomal mutations involved in antibiotic resistance in Staphylococcus aureus

Staphylococcus aureus is an important pathogen involved in infections in both the community and hospital setting. Strains that are resistant to multiple classes of antibiotics, particularly methicillin-resistant strains (MRSA), are prevalent in nosocomial infections and are associated with high morbidity and mortality rates. Such antibiotic-resistant strains limit the therapeutic options and place a burden on the health care system. In the hospital setting, horizontal gene transfer plays an important role in disseminating antibiotic resistant determinants among S. aureus. However, resistance to all known classes of antibiotics have been attributed to genes found within the S. aureus chromosome or to due to mutation as a result of selection pressure. Spontaneous mutations, in particular, are pivotal in the emergence of novel resistances. Consequently, newer drugs with better activity and/or antibacterial agents with novel targets need to be developed to combat and control the further spread of antibiotic resistance

Clinical classrooms : reflections on the choice of technologies when creating a new blended learning experience

This study analyses how technology supported the roll out of a new teaching approach for medical students, in order to improve engagement with traditional lecture content. A flipped classroom approach was implemented during the teaching of Infectious Diseases and Immunity using a modified Team Based Learning (TBL) learning design. Students first viewed a set of online lectures, followed by a face-to-face session called a Clinical Classroom. In the Clinical Classroom students participated in team based quizzes and discussions. Students were surveyed on six occasions to collect data on how this new approach helped their learning and staff reflected how their assumptions changed over the course of their teaching. Medical students generally valued having their lectures divided into smaller sections and placed online, followed by the clinical classroom. There were some limitations with the technology (such as lack of access to the questions after the class), which will be addressed in future iterations of the course

Evolutionary dynamics of Enterococcus faecium reveals complex genomic relationships between isolates with independent emergence of vancomycin resistance.

Background: Enterococcus faecium, a major cause of hospital-acquired infections, remains problematic because of its propensity to acquire resistance to vancomycin, which currently is considered first-line therapy. Here, we assess the evolution and resistance acquisition dynamics of E. faecium in a clinical context using a series of 132 blood-stream infection isolates from a single hospital. All isolates, of which 49 (37%) were vancomycin resistant, underwent whole-genome sequencing. Results: E. faecium was found to be subject to high rates of recombination with little evidence of sequence importation from outside the local E. faecium population. Apart from disrupting phylogenetic reconstruction, recombination was frequent enough to invalidate MLST typing in the identification of clonal expansion and transmission events, suggesting that where available, whole-genome sequencing should be used in tracing the epidemiology of E. faecium nosocomial infections and establishing routes of transmission. Several forms of the Tn1549-like element-vanB gene cluster, that was exclusively responsible for vancomycin resistance, appeared and spread within the hospital during the study period. Several transposon gains and losses and instances of in situ evolution were inferred and although usually chromosomal, the resistance element was also observed on a plasmid background. There was qualitative evidence for clonal expansions of both vancomycin-resistant and vancomycin-susceptible E. faecium with evidence of hospital specific sub-clonal expansion. Conclusions: Our data are consistent with continuing evolution of this established hospital pathogen and confirm hospital vancomycin-susceptible and -resistant E. faecium patient transmission events, underscoring the need for careful consideration before modifying current E. faecium infection control strategies

Shaping minds to action: An evaluation of the environmental influences of primary school students in an urbanizing community

Environmental perspectives are shaped by both affective and cognitive domains of education. In the urbanizing municipality of Balanga City, the primary school students of its 19 public schools were reported to have a skewed perspective of the environment, equating the term to only the natural components of their surroundings. This does not prevent the students from being actively concerned about the environment, but their confusion is aggravated by the contrasting habits observed in their households to those taught in school. Education is only a limited means to help develop sustainable practices needed as the global community addresses the challenges brought by climate change so to determine how to further develop the environmental knowledge of primary school students in Balanga City, and the influences enumerated by the children of its public schools were studied. Based on the students’ response, their school and television provide the fundamentals for their understanding of the environment, but the social atmosphere in their homes causes the trivialization of the environmental information they acquire. The ease by which these students are compelled to let go of environment-friendly habits may be caused by the absence of a solid cognitive foundation of environmental science due to the integrated curriculum design for teaching science to elementary students and the lack of sufficient training of the teachers involved. Although reiteration and emphasis of learned environmental principles in school can also come from mass media, the forms the students are exposed to are local and subject to sensationalism. There is a lack of sufficient infrastructure needed to expose the students to global viewpoints and issues about the environment, while those with immediate family members overseas have limited avenues for sharing their external influences. Involving the family in environmental education is the key, together with proper training of faculty and a modification of how environmental science is taught, to create an effective system for the improvement of the environmental perspectives of the children of Balanga City. Though environmental education may rely on the linearity of communication, the meeting point of the social influences of these children should emphasize the values of environmental stewardship for them to ascertain the right perspectives toward the environment. © 2014, Springer Science+Business Media Dordrecht

Polyclonal emergence of vanA vancomycin-resistant Enterococcus faecium in Australia

Objectives: To investigate the genetic context associated with the emergence of vanA VRE in Australia. Methods: The whole genomes of 18 randomly selected vanA-positive Enterococcus faecium patient isolates, collected between 2011 and 2013 from hospitals in four Australian capitals, were sequenced and analysed. Results: In silico typing and transposon/plasmid assembly revealed that the sequenced isolates represented (in most cases) different hospital-adapted STs and were associated with a variety of different Tn1546 variants and plasmid backbone structures. Conclusions: The recent emergence of vanA VRE in Australia was polyclonal and not associatedwith the dissemination of a single 'dominant' ST or vanA-encoding plasmid. Interestingly, the factors contributing to this epidemiological change are not known and future studies may need to consider investigation of potential community sources

Evolutionary dynamics of Enterococcus faecium reveals complex genomic relationships between isolates with independent emergence of vancomycin resistance.

Background: Enterococcus faecium, a major cause of hospital-acquired infections, remains problematic because of its propensity to acquire resistance to vancomycin, which currently is considered first-line therapy. Here, we assess the evolution and resistance acquisition dynamics of E. faecium in a clinical context using a series of 132 blood-stream infection isolates from a single hospital. All isolates, of which 49 (37%) were vancomycin resistant, underwent whole-genome sequencing. Results: E. faecium was found to be subject to high rates of recombination with little evidence of sequence importation from outside the local E. faecium population. Apart from disrupting phylogenetic reconstruction, recombination was frequent enough to invalidate MLST typing in the identification of clonal expansion and transmission events, suggesting that where available, whole-genome sequencing should be used in tracing the epidemiology of E. faecium nosocomial infections and establishing routes of transmission. Several forms of the Tn1549-like element-vanB gene cluster, that was exclusively responsible for vancomycin resistance, appeared and spread within the hospital during the study period. Several transposon gains and losses and instances of in situ evolution were inferred and although usually chromosomal, the resistance element was also observed on a plasmid background. There was qualitative evidence for clonal expansions of both vancomycin-resistant and vancomycin-susceptible E. faecium with evidence of hospital specific sub-clonal expansion. Conclusions: Our data are consistent with continuing evolution of this established hospital pathogen and confirm hospital vancomycin-susceptible and -resistant E. faecium patient transmission events, underscoring the need for careful consideration before modifying current E. faecium infection control strategies

Can molecular DNA-based techniques unravel the truth about diabetic foot infections?

Diabetes foot infections (DFI) are a common condition and a major causal pathway to lower extremity amputation. Identification of causative pathogens is vital in directing antimicrobial therapy. Historically, clinicians have relied upon culture-dependent techniques that are now acknowledged as both being selective for microorganisms that thrive under the physiological and nutritional constraints of the microbiology laboratory, and that grossly underestimate the microbial diversity of a sample. The amplification and sequence analysis of the 16S rRNA gene has revealed a diversity of microorganisms in DFIs, extending the view of the diabetic foot microbiome. The interpretation of these findings and their relevance to clinical care remains largely unexplored. The advent of molecular methods that are culture-independent and employ massively parallel DNA sequencing technology represent a potential “game changer”. Metagenomics and its shotgun approach to surveying all DNA within a sample (whole genome sequencing, WGS) affords the possibility to characterize not only the microbial diversity within a DFI (i.e., “which microorganisms are present”) but the biological functions of the community such as virulence and pathogenicity (i.e., “what are the microorganisms capable of doing”), moving the focus from single species as pathogens to groups of species

Staphylococcus aureus dry-surface biofilms are not killed by sodium hypochlorite : implications for infection control

Background: Dry hospital environments are contaminated with pathogenic bacteria in biofilms, which suggests that current cleaning practices and disinfectants are failing. Aim: To test the efficacy of sodium hypochlorite solution against Staphylococcus aureus dry-surface biofilms. Methods: The Centers for Disease Control and Prevention Biofilm Reactor was adapted to create a dry-surface biofilm, containing 1.36x107 S. aureus/coupon, by alternating cycles of growth and dehydration over 12 days. Biofilm was detected qualitatively using live/dead stain confocal laser scanning microscopy (CLSM), and quantitatively with sonicated viable plate counts and crystal violet assay. Sodium hypochlorite (1000 to 20,000 parts per million) was applied to the dry-surface biofilm for 10 min, coupons were rinsed three times, and residual biofilm viability was determined by CLSM, plate counts and prolonged culture up to 16 days. Isolates before and after exposure underwent minimum inhibitory concentration (MIC) and minimum eradication concentration (MEC) testing, and one pair underwent whole-genome sequencing. Findings: Hypochlorite exposure reduced plate counts by a factor of 7 log10, and reduced biofilm biomass by a factor of 100; however, staining of residual biofilm showed that live S. aureus cells remained. On prolonged incubation, S. aureus regrew and formed biofilms. Post-exposure S. aureus isolates had MICs and MECs that were not significantly different from the parent strains. Whole-genome sequencing of one pre- and post-exposure pair found that they were virtually identical. Conclusions: Hypochlorite exposure led to a 7-log kill but the organisms regrew. No resistance mutations occurred, implying that hypochlorite resistance is an intrinsic property of S. aureus biofilms. The clinical significance of this warrants further study