Jason Barnhill

RGA protein associates with a TRPV ion channel during biosynthesis and trafficking.

TRPV ion channels transduce a range of temperature stimuli. We proposed that analysis of the protein–protein interactions made by TRPV2 might give insight into the key issues surrounding this channel. These issues include the potential functional significance of TRPV2 in non‐sensory tissues, the molecules involved in transducing its activation signal(s) and the mechanism by which its trafficking to the cell surface is regulated. Here we describe the interaction of TRPV2 channel with the RGA gene product. RGA is a four‐transmembrane domain, intracellularly localized protein. RGA associates with TRPV2 in a rat mast cell line that is a native context for both proteins. The interaction between TRPV2 and RGA is transient and occurs intracellularly. RGA does not accompany TRPV2 to the cell surface. Formation of the TRPV2/RGA complex is dependent upon a cellular glycosylation event, suggesting that RGA may play a chaperone or targeting role for TRPV2 during the maturation of the ion channel protein. These data record a novel protein–protein interaction for TRPV2 and provide a foundation for future study of the potential regulatory contribution of RGA to TRPV2 function.

Real time application of whole genome sequencing for outbreak investigation – What is an achievable turnaround time?

Whole genome sequencing (WGS) is increasingly employed in clinical settings, though few assessments of turnaround times (TAT) have been performed in real-time. In this study, WGS was used to investigate an unfolding outbreak of vancomycin resistant Enterococcus faecium (VRE) among 3 patients in the ICU of a tertiary care hospital. Including overnight culturing, a TAT of just 48.5 h for a comprehensive report was achievable using an Illumina Miseq benchtop sequencer. WGS revealed that isolates from patient 2 and 3 differed from that of patient 1 by a single nucleotide polymorphism (SNP), indicating nosocomial transmission. However, the unparalleled resolution provided by WGS suggested that nosocomial transmission involved two separate events from patient 1 to patient 2 and 3, and not a linear transmission suspected by the time line. Rapid TATs are achievable using WGS in the clinical setting and can provide an unprecedented level of resolution for outbreak investigations.

Characterization of the cortisol stress response to sedation and anesthesia in children.

CONTEXT The cortisol stress response to sedation and anesthesia in children is not well characterized. It is not clear whether it is necessary to give stress doses of corticosteroids to children with adrenal insufficiency undergoing sedated procedures. OBJECTIVE Our objective was to describe the cortisol stress response to sedation and anesthesia in normal children. DESIGN, SETTING, AND PATIENTS This was a prospective cohort study of 149 children ages 1 month to 17 yr who presented for routine sedated procedures. Salivary cortisol was measured at baseline, every 30 min during procedures, at completion, and at recovery. MAIN OUTCOME MEASURES We evaluated relative change in salivary cortisol from baseline for level of sedation achieved and type of procedure performed. RESULTS In total, 117 patients had adequate samples collected, and 110 were included in the main analysis. Twenty-five percent of patients showed an increase in salivary cortisol greater than four times baseline, consistent with a stress response. Mean salivary cortisol increased more than 3-fold from baseline (3.7±0.4, P<0.001) for all patients in the study. There was no difference for change in cortisol when comparing by level of sedation achieved or by type of procedure performed. The majority of patients with a stress response had their highest levels in the recovery phase, after their procedure was completed. CONCLUSION Sedation and anesthesia can induce a significant rise in cortisol in children. Additional studies should be performed to validate our results and to determine whether stress dosing of corticosteroids may be needed for children with adrenal insufficiency undergoing sedated procedures.

Antibiotic resistance, molecular characterizations, and clinical manifestations of Campylobacteriosis at a military medical center in Hawaii from 2012–2016: a retrospective analysis

Hawaii has one of the highest incidences of Campylobacteriosis in the United States, but there remains little published data on circulating strains or antimicrobial resistance. We characterized 110 clinical Campylobacter isolates (106 C. jejuni, 4 C. coli) processed at Tripler Army Medical Center in Honolulu, HI from 2012–2016. Twenty-five percent of C. jejuni isolates exhibited fluoroquinolone (FQ) resistance, compared with 16% for tetracycline (TET), and 0% for macrolides. Two of the four C. coli isolates were resistant to FQ, TET, and macrolides. C. jejuni isolates further underwent multilocus sequence typing, pulsed-field gel electrophoresis, and molecular capsular typing. Nineteen capsule types were observed, with two capsule types (HS2 and HS9) being associated with FQ resistance (p < 0.001 and p = 0.006, respectively). HS2 FQ-resistant isolates associated with clonal complex 21, possibly indicating clonal spread in FQ resistance. Macrolides should be considered for treatment of suspect cases due to lack of observed resistance.

An Analysis of Staphylococcus aureus Infections at a Military Medical Center Using the PLEX-ID Combined Polymerase Chain Reaction-Mass Spectrometry System

Staphylococcus aureus (S. aureus) is a major cause of morbidity in the military health care setting. Culture-based methods are the most common means of identifying infections caused by this agent. However, culture-based methods lack sensitivity and specificity. The Abbott PLEX-ID instrument uses a combination of the polymerase chain reaction and mass spectrometry for the identification of bacterial isolates. We investigated whether the Abbott PLEX-ID system could identify S. aureus in clinical material and facilitate the epidemiological analysis of individual isolates. The PLEX-ID system positively identified 100% of isolates previously found to be methicillin resistant S. aureus by culture. In addition, analysis using the PLEX-ID software revealed that the majority of S. aureus isolates at Tripler Army Medical Center derive from clonal complex 8 and nearly 100% of these strains express the R-variant of the Panton-Valentine leukocidin virulence factor. These results demonstrate the utility of the PLEX-ID system in identifying clinical isolates and reveal an unexpected level of homogeneity among clinical S. aureus isolates recovered at Tripler Army Medical Center. These results also demonstrate the utility of the PLEX-ID system in identifying the resistance patterns, predicting the virulence properties, and tracking the migration of bacterial pathogens in the clinical setting.