A prospective assessment of the medic autologous blood transfusion skills for field transfusion preparation.

BACKGROUND: Data demonstrate the benefit of blood product administration near point-of-injury (POI). Fresh whole blood transfusion from a pre-screened donor provides a source of blood at the POI when resources are constrained. We captured transfusion skills data for medics performing autologous blood transfusion training. METHODS: We conducted a prospective, observational study of medics with varying levels of experience. Inexperienced medics were those with minimal or no reported experience learning the autologous transfusion procedures, versus reported experience among special operations medics. When available, medics were debriefed after the procedure for qualitative feedback. We followed them for up to 7 days for adverse events. RESULTS: The median number of attempts for inexperienced and experienced medics was 1 versus 1 (interquartile range 1-1 for both, p = .260). The inexperienced medics had a slower median time to needle venipuncture access for the donation of 7.3 versus 1.5 min, needle removal after clamping time of 0.3 versus 0.2 min, time to bag preparation of 1.9 versus 1.0 min, time to IV access for reinfusion of 6.0 versus 3.0 min, time to transfusion completion of 17.3 versus 11.0 min, and time to IV removal of 0.9 versus 0.3 min (all p < .05). We noted one administrative safety event in which an allogeneic transfusion occurred. No major adverse events occurred. Qualitative data saturated around the need for quarterly training. CONCLUSIONS: Inexperienced medics have longer procedure times when training autologous whole blood transfusion skills. This data will help establish training measures of performance for skills optimization when learning this procedure.

Face mask leak with nasal cannula during noninvasive positive pressure ventilation: A randomized crossover trial.

BACKGROUND: Nasal cannula can achieve apneic oxygenation during emergency intubation. However, pre-procedure nasal cannula placement may be difficult in patients undergoing non-invasive positive pressure ventilation (NPPV) prior to intubation. Our objective was to compare mask leak during NPPV with versus without simultaneous application of nasal cannula. We hypothesized mask leak would be no worse with concomitant use of nasal cannula (non-inferiority design). METHODS: We performed a randomized crossover non-inferiority study of healthy volunteers. We randomized subjects undergoing 60s trials of NPPV (10cmH2O continuous positive airway pressure) to either NPPV alone (NPPV-a) or NPPV with nasal cannula at 15L/min (NPPV-nc). After a brief rest period, all subjects underwent the alternative intervention. The primary outcome was time averaged mask leak over 60s (L/min). We defined a non-inferiority margin of 5L/min. RESULTS: We enrolled 64 subjects. Mean time-averaged mask leak was 2.2L/min for NPPV-a versus 4.0L/min for NPPV-nc for a difference of 1.7L/min (one-sided 95% CI -∞ to 3.2L/min). NPPV-a resulted in higher mean minute volume received (13.5 versus 12.2L) and higher mean respiratory rates (14.8 versus 13.5 breaths per minute). CONCLUSION: The addition of nasal cannula during NPPV does not significantly increase mask leak. The simultaneous application of nasal cannula with NPPV may be a useful strategy to streamline airway management among patients undergoing NPPV prior to intubation.

End-Tidal Oxygen Saturation with Nasal Cannula During Noninvasive Positive Pressure Ventilation: A Randomized Crossover Trial.

BACKGROUND: Simultaneous use of nasal cannula (NC) with noninvasive positive pressure ventilation (NIPPV) may help streamline the transition from preoxygenation to intubation with apneic oxygenation in patients with deteriorating respiratory status, but may also compromise preoxygenation by impairing NIPPV mask seal. OBJECTIVES: To demonstrate that end-tidal oxygen (EtO2) after NIPPV with NC is noninferior to that of NIPPV without NC. METHODS: We conducted a randomized cross-over noninferiority study using healthy volunteers. All subjects underwent a 3-min trial of NIPPV with or without high-flow NC at 15 L/min of oxygen, followed by a 5-min washout period, and then a second 3-min trial of the opposite intervention. We randomized subjects to order of interventions. The primary outcome was postintervention EtO2 as measured by immediate exhalation into an oxygen analyzer after the 3-min ventilation period. We compared this outcome between the two study arms using an absolute 5% noninferiority margin. RESULTS: We enrolled 37 subjects, each of whom underwent both interventions of NIPPV alone and NIPPV with 15 L/min NC. The paired mean difference in EtO2 between NIPPV with NC measurements vs. NC alone measurements was 0.5% (95% confidence interval -∞ to 2.7%). Analyses stratified by order of intervention yielded similar results. CONCLUSIONS: The mean difference confidence interval did not include the noninferiority margin. Hence, NIPPV with NC seems noninferior to NIPPV alone with regard to EtO2. These results indicate that concomitant use of NC with NIPPV may be an appropriate preoxygenation strategy in anticipation of the potential need for transition to intubation.

The Tourniquet Gap: A Pilot Study of the Intuitive Placement of Three Tourniquet Types by Laypersons.

BACKGROUND: The "Stop the Bleed" campaign in the United States advocates for nonmedical personnel to be trained in basic hemorrhage control and that "bleeding control kits" be available in high-risk areas. However, it is not clear which tourniquets are most effective in the hands of laypersons. OBJECTIVES: The objective of this pilot study was to determine which tourniquet type was the most intuitive for a layperson to apply correctly. METHODS: This project is a randomized study derived from a "Stop the Bleed" education initiative conducted between September 2016 and March 2017. Novice tourniquet users were randomized to apply one of three commercially available tourniquets (Combat Action Tourniquet [CAT; North American Rescue, LLC, Greer, SC], Ratcheting Medical Tourniquet [RMT; m2 Inc., Winooski, VT], or Stretch Wrap and Tuck Tourniquet [SWAT-T; TEMS Solutions, LLC, Salida, CO]) in a controlled setting. Individuals with formal medical certification, prior military service, or prior training with tourniquets were excluded. The primary outcome of this study was successful tourniquet placement. RESULTS: Of 236 possible participants, 198 met the eligibility criteria. Demographics were similar across groups. The rates of successful tourniquet application for the CAT, RMT, and SWAT-T were 16.9%, 23.4%, and 10.6%, respectively (p = 0.149). The most common causes of application failure were: inadequate tightness (74.1%), improper placement technique (44.4%), and incorrect positioning (16.7%). CONCLUSION: Our pilot study on the intuitive nature of applying commercially available tourniquets found unacceptably high rates of failure. Large-scale community education efforts and manufacturer improvements of tourniquet usability by the lay public must be made before the widespread dissemination of tourniquets will have a significant public health effect.

A Survey of Wilderness Medicine Analgesia Practice Patterns.

INTRODUCTION: In 2014, the Wilderness Medical Society (WMS) published guidelines for the treatment of acute pain in remote settings. We surveyed wilderness medicine providers on self-reported analgesia prescribing practices. METHODS: We conducted a prospective, anonymous survey. Respondents were recruited from the WMS annual symposium in 2016. All willing attendees were included. RESULTS: During the symposium, we collected a total of 124 surveys (68% response rate). Respondent age was 42±12 (24-79) years (mean±SD with range), 58% were male, and 69% reported physician-level training. All respondents had medical training of varying levels. Of the physicians reporting a specialty, emergency medicine (59%, n=51), family medicine (13%, n=11), and internal medicine (8%, n=7) were reported most frequently. Eighty-one (65%) respondents indicated they prefer a standardized pain assessment tool, with the 10-point numerical rating scale being the most common (54%, n=67). Most participants reported preferring oral acetaminophen (81%, n=101) or nonsteroidal anti-inflammatory drugs (NSAID) (91%, n=113). Of those preferring NSAID, most reported administering acetaminophen as an adjunct (82%, n=101). Ibuprofen was the most frequently cited NSAID (71%, n=88). Of respondents who preferred opioids, the most frequently preferred opioid was oxycodone (26%, n=32); a lower proportion of respondents reported preferring oral transmucosal fentanyl citrate (9%, n=11). Twenty-five (20%, n=25) respondents preferred ketamine. CONCLUSIONS: Wilderness medicine practitioners prefer analgesic agents recommended by the WMS for the treatment of acute pain. Respondents most frequently preferred acetaminophen and NSAIDs.

Multi-laboratory validation study of multilocus variable-number tandem repeat analysis (MLVA) for Salmonella enterica serovar Enteritidis, 2015.

Multilocus variable-number tandem repeat analysis (MLVA) is a rapid and reproducible typing method that is an important tool for investigation, as well as detection, of national and multinational outbreaks of a range of food-borne pathogens. Salmonella enterica serovar Enteritidis is the most common Salmonella serovar associated with human salmonellosis in the European Union/European Economic Area and North America. Fourteen laboratories from 13 countries in Europe and North America participated in a validation study for MLVA of S. Enteritidis targeting five loci. Following normalisation of fragment sizes using a set of reference strains, a blinded set of 24 strains with known allele sizes was analysed by each participant. The S. Enteritidis 5-loci MLVA protocol was shown to produce internationally comparable results as more than 90% of the participants reported less than 5% discrepant MLVA profiles. All 14 participating laboratories performed well, even those where experience with this typing method was limited. The raw fragment length data were consistent throughout, and the inter-laboratory validation helped to standardise the conversion of raw data to repeat numbers with at least two countries updating their internal procedures. However, differences in assigned MLVA profiles remain between well-established protocols and should be taken into account when exchanging data.

Sentinel community Clostridium difficile infection (CDI) surveillance in Scotland, April 2013 to March 2014.

Surveillance of Clostridium difficile infection (CDI) in Scotland does not currently distinguish between CDI cases from hospitals and the community. Therefore, the incidence of CDI in the community is unknown, and the burden of disease and the relationship with the hospital/healthcare setting is not well understood. A one-year sentinel community surveillance programme was initiated in collaboration with five Scottish health boards in 2013 (representing 36% of all CDI cases reported in Scotland). Inclusion criteria were all cases aged ≥15 years with a CDI diagnosis in the community or within 48 h following admission to hospital. CDI cases were categorised according to definitions used by the European Centre for Disease Prevention and Control. 256 CDI cases met the inclusion criteria, of which 158 (62%) were community-associated cases (CA-CDI). This represented 26% of all cases reported during the surveillance period by the participating health boards (n = 614). The overall CA-CDI incidence rate was 9.9 per 100 000 population per year. CA-CDI cases were more likely to be female and younger, compared to hospital acquired cases (HA-CDI). The total proportion of cases that had onset in the community was 27%. Ribotypes 015, 002, 078 and 005 were the most common types isolated from both CA-CDI and HA-CDI cases. There were no statistically significant differences between the proportion of types that were either CA-CDI or HA-CDI. Of the CA-CDI cases, 37% had not received antibiotics in the 12 weeks preceding CDI diagnosis, 4% were resident in care homes, and the case-fatality rate for CA-CDI cases was 5.6% (with a 30-day mortality rate for CA-CDI of 0.44 per 100 000 population per year). This study has shown that a substantial proportion of CDI cases reported in Scotland are community associated and that there are close links between the community and healthcare settings. It is therefore essential to monitor the trends in CDI in the community at a national level. The study also provides evidence for the need to examine the feasibility for development of interventions to reduce the burden in the community in addition to hospitals.

Global phylogeny of Shigella sonnei strains from limited single nucleotide polymorphisms (SNPs) and development of a rapid and cost-effective SNP-typing scheme for strain identification by high-resolution melting analysis.

The current Shigella sonnei pandemic involves geographically associated, multidrug-resistant clones. This study has demonstrated that S. sonnei phylogeny can be accurately defined with limited single nucleotide polymorphisms (SNPs). By typing 6 informative SNPs using a high-resolution melting (HRM) assay, major S. sonnei lineages/sublineages can be identified as defined by whole-genome variation.

An ecological approach to assessing the epidemiology of antimicrobial resistance in animal and human populations.

We examined long-term surveillance data on antimicrobial resistance (AMR) in Salmonella Typhimurium DT104 (DT104) isolates from concurrently sampled and sympatric human and animal populations in Scotland. Using novel ecological and epidemiological approaches to examine diversity, and phenotypic and temporal relatedness of the resistance profiles, we assessed the more probable source of resistance of these two populations. The ecological diversity of AMR phenotypes was significantly greater in human isolates than in animal isolates, at the resolution of both sample and population. Of 5200 isolates, there were 65 resistance phenotypes, 13 unique to animals, 30 unique to humans and 22 were common to both. Of these 22, 11 were identified first in the human isolates, whereas only five were identified first in the animal isolates. We conclude that, while ecologically connected, animals and humans have distinguishable DT104 communities, differing in prevalence, linkage and diversity. Furthermore, we infer that the sympatric animal population is unlikely to be the major source of resistance diversity for humans. This suggests that current policy emphasis on restricting antimicrobial use in domestic animals may be overly simplistic. While these conclusions pertain to DT104 in Scotland, this approach could be applied to AMR in other bacteria-host ecosystems.

Population genetic structure of 4,12:a:- Salmonella enterica strains from harbor porpoises.

According to pulsed-field gel electrophoresis (PFGE) typing, 4,12:a:- Salmonella enterica isolates from harbor porpoises are highly diverse. However, porpoise isolates belong to only two multilocus sequence types within the eBurst group 18 (eBG18) genetic cluster, which also includes S. enterica serovars Bispebjerg and Abortusequi. Isolates of other, serologically similar serovars belong to unrelated eBGs. These assignments to eBGs were supported by eBG-specific sequences of the flagellar gene fliC.

Salmonella enterica strains belonging to O serogroup 1,3,19 induce chlorosis and wilting of Arabidopsis thaliana leaves.

The number of outbreaks and illness linked to the consumption of contaminated salad leaves have increased dramatically in the last decade. Escherichia coli and Salmonella enterica are the most common food-borne pathogens linked to consumption of fresh produce. Different serovars of S. enterica subspecies enterica have been shown to bind the surface of salad leaves, to exhibit tropism towards the stomata and to invade leaves and reach the underlying mesophyll. However the consequences of leaf invasion are not known. Here we show that following infiltration, serovars Typhimurium, Enteritidis, Heidelberg and Agona, as well as strains of S. enterica subspecies arizonae and diarizonae, survive in the mesophyll of Arabidopsis thaliana leaves but induce neither leaf chlorosis nor wilting. In contrast, S. Senftenberg induced strong leaf wilting 4 days post infiltration in A. thaliana accession Col-0 but not in accession Ws-0. Dead S. Senftenberg and bacterial lysates also induced leaf wilting. We found that mutations in the Arabidopsis pathogen associated molecular pattern (PAMP) recognition receptors (PRRs) FLS2, which recognizes flagellin, and EFR, which recognizes the bacterial elongation factor EF-Tu, had no effect on the wilting response of A. thaliana to S. Senftenberg. Infiltration of A. thaliana leaves with serovars Cannstatt, Krefeld and Liverpool, which like Senftenberg belong to Salmonella serogroup E(4) (O:1,3,19), also resulted in rapid leaf wilting, while all tested rough S. Senftenberg strains (lacking the O antigen) failed to elicit leaf wilting. These results suggest that the Salmonella O antigen 1,3,19 specifically triggers leaf chlorosis and wilting in A. thaliana.

Clostridium difficile in ready-to-eat salads, Scotland.

Of 40 ready-to-eat salads, 3 (7.5%) were positive for Clostridium difficile by PCR. Two isolates were PCR ribotype 017 (toxin A-, B+), and 1 was PCR ribotype 001. Isolates were susceptible to vancomycin and metronidazole but variably resistant to other antimicrobial drugs. Ready-to-eat salads may be potential sources for virulent C. difficile.

Assessment of the potential risk of infection associated with Clostridium difficile from porcine xenografts.

There are numerous concerns over the potential for transfer of pathogens between species during clinical xenotransplantation, and although current clinical application is limited, porcine xenografts have been previously used to treat patients with severe burns. Donor animals providing the xenografts are sourced from a healthy commercial herd, however, as pigs are a known source of zoonotic agents, a number of diseases are required to be excluded from pigs used for xenotransplantation purposes. Many studies have indicated the relevance of viral zoonoses, however, little has been done with regard to the potential for transfer of pathogens related to health care associated infections. Clostridium difficile is a major cause of neonatal enteritis in pigs and an important feature of this organism is that pigs can be asymptomatic carriers. This study has examined the incidence of C. difficile PCR ribotypes present in healthy donor pigs to determine if pig faeces, and in particular, contamination of skin with faecal matter, is a potential route for the transfer of C. difficile. Animals were found to have human ribotype 017 present in the faecal matter, however, no C. difficile was isolated from skin samples taken from the same animals. In addition, due to the risk factors associated with C. difficile infection, the antimicrobial susceptibility of the C. difficile isolates has been determined.

Characterization of the genomes of a diverse collection of Salmonella enterica serovar Typhimurium definitive phage type 104.

Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104) has caused significant morbidity and mortality in humans and animals for almost three decades. We completed the full DNA sequence of one DT104 strain, NCTC13348, and showed that significant differences between the genome of this isolate and the genome of the previously sequenced strain Salmonella serovar Typhimurium LT2 are due to integrated prophage elements and Salmonella genomic island 1 encoding antibiotic resistance genes. Thirteen isolates of Salmonella serovar Typhimurium DT104 with different pulsed-field gel electrophoresis (PFGE) profiles were analyzed by using multilocus sequence typing (MLST), plasmid profiling, hybridization to a pan-Salmonella DNA microarray, and prophage-based multiplex PCR. All the isolates belonged to a single MLST type, sequence type ST19. Microarray data demonstrated that the gene contents of the 13 DT104 isolates were remarkably conserved. The PFGE DNA fragment size differences in these isolates could be explained to a great extent by differences in the prophage and plasmid contents. Thus, here the nature of variation in different Salmonella serovar Typhimurium DT104 isolates is further defined at the gene and whole-genome levels, illustrating how this phage type evolves over time.

Packed with Salmonella--investigation of an international outbreak of Salmonella Senftenberg infection linked to contamination of prepacked basil in 2007.

Salmonella Senftenberg is uncommon in the United Kingdom. In January-June 2007, the Health Protection Agency reported on 55 primary human cases of Salmonella Senftenberg in England and Wales. In May 2007, fresh basil sold in the United Kingdom was found to be contaminated with Salmonella Senftenberg. We launched an investigation to elucidate the cause of this outbreak. Isolates were examined using plasmid profiling and pulsed-field gel electrophoresis, and the outbreak strain (SSFTXB.0014) was identified. We enquired via Enter-net whether other countries had isolated the outbreak strain, analyzed samples of fresh herbs from U.K. retailers, and interviewed patients on food history. Thirty-two patient-cases were referred to this outbreak in England and Wales. Onsets of illness occurred between 5 March and 6 June 2007. Fifty-six percent of patient-cases were females and 90% adults (>20 years old); three were admitted to hospital as a result of Salmonella infection. Scotland, Denmark, the Netherlands, and the United States reported on 19 cases of Salmonella Senftenberg infection presenting with the outbreak strain since January 2007. Eight samples of prepacked fresh basil imported from Israel tested positive with the same strain. A minority of patients could recall the consumption of basil before illness, and some reported consumption of products where basil was a likely ingredient. Environmental investigations in Israel did not identify the contamination source. Microbiological evidence suggested an association between contamination of fresh basil and the cases of Salmonella Senftenberg infection, leading to withdrawal of basil from all potentially affected batches from the U.K. market.

Prehospital airway procedures performed in trauma patients by ground forces in Afghanistan.

BACKGROUND: Airway management is of critical importance in combat trauma patients. Airway compromise is the second leading cause of potentially survivable death on the battlefield and accounts for approximately 1 in 10 preventable deaths. Reports from the Iraq and Afghanistan wars indicate 4% to 7% incidence of airway interventions on casualties transported to combat hospitals. The goal of this study was to describe airway management in the prehospital combat setting and document airway devices used on the battlefield. METHODS: This study is a retrospective review of casualties that required a prehospital lifesaving airway intervention during combat operations in Afghanistan. We obtained data from the Prehospital Trauma Registry that was linked to the Department of Defense Trauma Registry for outcome data for the time period between January 2013 and September 2014. RESULTS: Seven hundred five total trauma patients were included, 16.9% required a prehospital airway management procedure. There were 132 total airway procedures performed, including 83 (63.4%) endotracheal intubations and 26 (19.8%) nasopharyngeal airway placements. Combat medics were involved in 48 (36.4%) of airway cases and medical officers in 73 (55.3%). Most (94.2%) patients underwent airway procedures due to battle injuries caused by explosion or gunshot wounds. Casualties requiring airway management were more severely injured and less likely to survive as indicated by Injury Severity Score, responsiveness level, Glascow Coma Scale, and outcome. CONCLUSION: Percentages of airway interventions more than tripled from previous reports from the wars in Afghanistan and Iraq. These changes are significant, and further study is needed to determine the causes. Casualties requiring airway interventions sustained more severe injuries and experienced lower survival than patients who did not undergo an airway procedure, findings suggested in previous reports. LEVEL OF EVIDENCE: Prognostic and epidemiological study, level III.

Stop the Bleed: The Effect of Hemorrhage Control Education on Laypersons' Willingness to Respond During a Traumatic Medical Emergency.

BACKGROUND: The "Stop the Bleed" campaign advocates for non-medical personnel to be trained in basic hemorrhage control. However, it is not clear what type of education or the duration of instruction needed to meet that requirement. The objective of this study was to determine the impact of a brief hemorrhage control educational curriculum on the willingness of laypersons to respond during a traumatic emergency. METHODS: This "Stop the Bleed" education initiative was conducted by the University of Texas Health San Antonio Office of the Medical Director (San Antonio, Texas USA) between September 2016 and March 2017. Individuals with formal medical certification were excluded from this analysis. Trainers used a pre-event questionnaire to assess participants knowledge and attitudes about tourniquets and responding to traumatic emergencies. Each training course included an individual evaluation of tourniquet placement, 20 minutes of didactic instruction on hemorrhage control techniques, and hands-on instruction with tourniquet application on both adult and child mannequins. The primary outcome in this study was the willingness to use a tourniquet in response to a traumatic medical emergency. RESULTS: Of 236 participants, 218 met the eligibility criteria. When initially asked if they would use a tourniquet in real life, 64.2% (140/218) responded "Yes." Following training, 95.6% (194/203) of participants responded that they would use a tourniquet in real life. When participants were asked about their comfort level with using a tourniquet in real life, there was a statistically significant improvement between their initial response and their response post training (2.5 versus 4.0, based on 5-point Likert scale; P<.001). CONCLUSION: In this hemorrhage control education study, it was found that a short educational intervention can improve laypersons' self-efficacy and reported willingness to use a tourniquet in an emergency. Identified barriers to act should be addressed when designing future hemorrhage control public health education campaigns. Community education should continue to be a priority of the "Stop the Bleed" campaign. Ross EM , Redman TT , Mapp JG , Brown DJ , Tanaka K , Cooley CW , Kharod CU , Wampler DA . Stop the bleed: the effect of hemorrhage control education on laypersons' willingness to respond during a traumatic medical emergency. Prehosp Disaster Med. 2018;33(2):127-132.

New Variant of Multidrug-Resistant Salmonella enterica Serovar Typhimurium Associated with Invasive Disease in Immunocompromised Patients in Vietnam.

Nontyphoidal Salmonella (NTS), particularly Salmonella enterica serovar Typhimurium, is among the leading etiologic agents of bacterial enterocolitis globally and a well-characterized cause of invasive disease (iNTS) in sub-Saharan Africa. In contrast, S Typhimurium is poorly defined in Southeast Asia, a known hot spot for zoonotic disease with a recently described burden of iNTS disease. Here, we aimed to add insight into the epidemiology and potential impact of zoonotic transfer and antimicrobial resistance (AMR) in S Typhimurium associated with iNTS and enterocolitis in Vietnam. We performed whole-genome sequencing and phylogenetic reconstruction on 85 human (enterocolitis, carriage, and iNTS) and 113 animal S Typhimurium isolates isolated in Vietnam. We found limited evidence for the zoonotic transmission of S Typhimurium. However, we describe a chain of events where a pandemic monophasic variant of S Typhimurium (serovar I:4,[5],12:i:- sequence type 34 [ST34]) has been introduced into Vietnam, reacquired a phase 2 flagellum, and acquired an IncHI2 multidrug-resistant plasmid. Notably, these novel biphasic ST34 S Typhimurium variants were significantly associated with iNTS in Vietnamese HIV-infected patients. Our study represents the first characterization of novel iNTS organisms isolated outside sub-Saharan Africa and outlines a new pathway for the emergence of alternative Salmonella variants into susceptible human populations.IMPORTANCESalmonella Typhimurium is a major diarrheal pathogen and associated with invasive nontyphoid Salmonella (iNTS) disease in vulnerable populations. We present the first characterization of iNTS organisms in Southeast Asia and describe a different evolutionary trajectory from that of organisms causing iNTS in sub-Saharan Africa. In Vietnam, the globally distributed monophasic variant of Salmonella Typhimurium, the serovar I:4,[5],12:i:- ST34 clone, has reacquired a phase 2 flagellum and gained a multidrug-resistant plasmid to become associated with iNTS disease in HIV-infected patients. We document distinct communities of S Typhimurium and I:4,[5],12:i:- in animals and humans in Vietnam, despite the greater mixing of these host populations here. These data highlight the importance of whole-genome sequencing surveillance in a One Health context in understanding the evolution and spread of resistant bacterial infections.

Comparison of intestinal invasion and macrophage response of Salmonella Gallinarum and other host-adapted Salmonella enterica serovars in the avian host.

The purpose of this investigation was to study the host specific infection of Salmonella Gallinarum in chickens and to determine the contribution of intestinal invasion and macrophage survival in relation to systemic infection in the host. This was carried out by comparing the kinetics of infection of S. Gallinarum to that of other Salmonella host-adapted (S. Cholerae-suis, S. Dublin and S. Typhimurium) and host-specific (S. Pullorum and S. Abortus-ovis) serovars. Establishment of the rate of colonisation in intestinal tissue, bursa and systemic sites was carried out by oral infection in day-old and week-old birds. Salmonella Gallinarum was the only serovar capable of causing systemic infection in chickens, however, general colonising ability in the intestine and bursa demonstrated no apparent selective advantage for S. Gallinarum. Further quantification of gastrointestinal invasion was carried out using ligated loops in the small intestine. Invasion in the jejunum of the chicken intestine over 3h demonstrated that Salmonella Typhimurium invasion was statistically higher (P<0.01) when compared with S. Gallinarum. Specific sites of high lymphoid tissue concentration in the chicken, including the bursa of Fabricius and caecal tonsils, were also targeted in invasion assays to investigate possible areas of tissue tropism. S. Typhimurium demonstrated significantly higher (P<0.01) invasion at these sites when compared with S. Gallinarum. Infection of chicken macrophages with S. Gallinarum did not demonstrate increased multiplication and survival intracellularly when compared with other Salmonella serotypes. The only difference seen was with S. Abortus-ovis, which demonstrated a significantly lower (P<0.05 to 0.001) intracellular survival. Together these data suggest that although S. Gallinarum host specificity in the chicken correlates with systemic infection, intestinal and lymphoid tissue invasion in the bursa and caeca, and macrophage survival does not influence this outcome.