Outcomes Following Surgical and Nonsurgical Treatment for Uncomplicated Appendicitis in Older Adults.

Importance: The optimal treatment of acute uncomplicated appendicitis in older adults with frailty is not defined. Objective: To examine outcomes associated with treatment strategies for acute uncomplicated appendicitis in older adults with or without frailty. Design, Setting, and Participants: This retrospective cohort study used National Inpatient Sample data from adults 65 years or older with a diagnosis of uncomplicated appendicitis from January 1, 2016, to December 31, 2018. Data were analyzed from July to November 2023. The National Inpatient Sample database approximates a 20% stratified sample of all inpatient hospital discharges in the US. Exposures: Study patients were categorized into 3 groups: nonoperative management, immediate operation, and delayed operation. Main Outcomes and Measures: Clinical outcomes, including hospital complications and in-hospital mortality, were assessed among older adults with and without frailty, identified using an adapted claims-based frailty index. Results: A total of 24 320 patients were identified (median [IQR] age, 72 [68-79] years; 50.9% female). Of those, 7290 (30.0%) were categorized as having frailty. Overall, in-hospital mortality was 1.4%, and the incidence of complications was 37.3%. In patients with frailty, multivariable analysis showed both nonoperative management (odds ratio [OR], 2.89; 95% CI, 1.40-5.98; P < .001) and delayed appendectomy (OR, 3.80; 95% CI, 1.72-8.43; P < .001) were associated with increased in-hospital mortality compared with immediate appendectomy. In patients without frailty, immediate appendectomy was associated with increased hospital complications compared with nonoperative management (OR, 0.77; 95% CI, 0.64-0.94; P = .009) and lower hospital complications compared with delayed appendectomy (OR, 2.05; 95% CI, 1.41-3.00; P < .001). Conclusions and Relevance: In this cohort study of older adults with uncomplicated appendicitis, outcomes differed among management strategies based on frailty status. Routine frailty assessments incorporated in the care of older adult patients may help guide discussions for shared decision-making.

Initial management and outcomes of nonmalignant esophageal perforations: A Nationwide Inpatient Sample analysis.

BACKGROUND: Management of esophageal perforation includes open surgery, minimally invasive surgery, and endoscopic stent placement. This study analyzed initial treatment and the associated short-term outcomes. METHODS: A retrospective study using the National Inpatient Sample between October 2015 and December 2019 identified adults >18 years with esophageal perforation undergoing an initial nonelective esophageal procedure categorized into either open surgery, minimally invasive surgery, or endoscopic stent placement. Patients with esophageal cancer were excluded. Baseline characteristics and the van Walraven-weighted Elixhauser Comorbidity Index were identified. Outcomes included in-hospital mortality and postintervention complications. Univariable and multivariable Cox regression was used to compare in-hospital survival. RESULTS: In total, 3,345 patients met inclusion criteria: the median age was 62 years (interquartile range 50-72 years), and 1,310 (39%) were female. Open procedure was pursued in 2,650 (79%), minimally invasive surgery in 310 (9%), and endoscopic stent placement in 385 (12%) with no differences in van Walraven-weighted Elixhauser Comorbidity Index or mortality. Patients who underwent minimally invasive surgery had a greater proportion of gastrointestinal complications (P = .006); otherwise, there were no differences in postintervention complications. In total, 380 (11%) patients died and were significantly older, with greater van Walraven-weighted Elixhauser Comorbidity Index, and had more postintervention complications. Univariable Cox regression identified age (hazard ratio 1.95, P < .001), van Walraven-weighted Elixhauser Comorbidity Index (hazard ratio 1.06, P < .001), stent placement (hazard ratio 1.93, P = .045), and transfer from a health facility (HR 2.40, P = .049) as associated with decreased in-hospital survival. Multivariable Cox regression revealed age (hazard ratio 1.041, P < .001) and van Walraven-weighted Elixhauser comorbidity index (hazard ratio 1.055, P < .001) were associated with decreased in-hospital survival. CONCLUSION: Patients with esophageal perforation had an 11% in-hospital mortality rate and significant associated complications regardless of intervention. Increasing age and comorbidities are associated with poorer in-hospital survival.

Safety of redo sleeve gastrectomy as a primary revisional procedure.

BACKGROUND: Insufficient weight loss after primary laparoscopic sleeve gastrectomy (LSG) occasionally requires revisional surgery. A few single-institution studies have examined the safety of redo LSG (RSG) and have shown mixed results. OBJECTIVES: The aim of this study was to evaluate the safety of RSG compared with LSG over a period of 30 days. SETTING: University of Southern California, United States; Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database. METHODS: The 2020-2021 MBSAQIP registry was used to evaluate patients who underwent RSG. Thirty-day outcomes were evaluated using univariable analysis and multivariable logistic and linear regression. RESULTS: A total of 226,029 patients were reviewed, of whom 1454 (.7%) underwent RSG and 224,575 (99.3%) underwent initial LSG. Patients who underwent RSG were older (45 versus 42 yr), predominantly female (86.2% versus 81.3%), had a lower body mass index (40.0 versus 43.4), fewer co-morbidities, and greater rates of gastroesophageal reflux (38.7% versus 25.1%). They demonstrated increased overall complications (3.6% versus 2.1%, P < .001) and a longer operative time (81 versus 62 min, P < .001), but there was no difference in mortality. On multivariable analysis, patients who underwent RSG were independently associated with an increased risk of overall postoperative complications (odds ratio [OR]: 1.493, P = .018), organ space infection (OR: 6.231, P < .001), staple line leak (OR: 12.838, P < .001), pneumonia (OR: 3.85, P = .013), ventilator requirement over 48 hours (OR: 6.404, P = .035), sepsis (OR: 4.397, P = .010), septic shock (OR: 8.669, P < .001), reoperation (OR: 1.808, P = .013), readmission (OR: 2.104, P < .001), reintervention (OR: 4.435, P < .001), and longer operative times (ß = 12.790, P < .001). CONCLUSIONS: In this national database study, RSG was associated with increased rates of postoperative complications and a longer operative time. Although these results are concerning, further studies are required to examine long-term outcomes.

The Emergence of Candida auris is Not Associated with Changes in Antifungal Prescription at Hospitals.

Purpose: This study describes the emergence of Candida auris in Hong Kong, focusing on the incidence and trends of different Candida species over time. Additionally, the study analyzes the relationship between C. auris and antifungal prescription, as well as the impact of outbreaks caused by C. auris. Patients and Methods: Data were collected from 43 public hospitals across seven healthcare networks (A to G) in Hong Kong, including Candida species culture and antifungal prescription information. Among 150,267 patients with 206,405 hospitalization episodes, 371,653 specimens tested positive for Candida species. Trends in Candida species and antifungal prescription were analyzed before (period 1: 2015 1Q to 2019 1Q) and after (period 2: 2019 2Q to 2023 2Q) the emergence of C. auris in Hong Kong. Results: Candida albicans was the most prevalent species, accounting for 57.1% (212,163/371,653) of isolations, followed by Candida glabrata (13.1%, 48,666), Candida tropicalis (9.2%, 34,261), and Candida parapsilosis (5.3%, 19,688). C. auris represented 2.0% of all Candida species isolations. Comparing period 2 to period 1, the trend of C. albicans remained stable, while C. glabrata, C. tropicalis, and C. parapsilosis demonstrated a slower increasing trend in period 2 than in period 1. Other species, including C. auris, exhibited a 1.1% faster increase in trend during period 2 compared to period 1. Network A, with the highest antifungal prescription, did not experience any outbreaks, while networks F and G had 40 hospital outbreaks due to C. auris in period 2. Throughout the study period, healthcare networks B to G had significantly lower antifungal prescription compared to network A, ranging from 54% to 78% less than that of network A. Conclusion: There is no evidence showing correlation between the emergence of C. auris and antifungal prescription in Hong Kong. Proactive infection control measures should be implemented to prevent nosocomial transmission and outbreak of C. auris.

Characterizing fitness and immune escape of SARS-CoV-2 EG.5 sublineage using elderly serum and nasal organoid.

SARS-CoV-2 Omicron variant has evolved into sublineages. Here, we compared the neutralization susceptibility and viral fitness of EG.5.1 and XBB.1.9.1. Serum neutralization antibody titer against EG.5.1 was 1.71-fold lower than that for XBB.1.9.1. However, there was no significant difference in virus replication between EG.5.1 and XBB.1.9.1 in human nasal organoids and TMPRSS2/ACE2 over-expressing A549 cells. No significant difference was observed in competitive fitness and cytokine/chemokine response between EG.5.1 and XBB.1.9.1. Both EG.5.1 and XBB.1.9.1 replicated more robustly in the nasal organoid from a younger adult than that from an older adult. Our findings suggest that enhanced immune escape contributes to the dominance of EG.5.1 over earlier sublineages. The combination of population serum susceptibility testing and viral fitness evaluation with nasal organoids may hold promise in risk assessment of upcoming variants. Utilization of serum specimens and nasal organoid derived from older adults provides a targeted risk assessment for this vulnerable population.

Identifying Pregnant Patients With Suspected Intimate Partner Violence.

INTRODUCTION: Intimate partner violence (IPV) is the leading cause of death in pregnant women. Although it can be difficult to identify patients experiencing IPV, injuries to the head, neck, or face due to an assault are known to correlate with intentional injury. The objective of this study is to assess the contemporary burden of IPV in pregnancy and describe the patient characteristics. METHODS: The National Inpatient Sample was queried for all pregnant women between January 2016 and December 2019. Patients were divided into two groups: suspected IPV (SIPV) and no-SIPV groups. We defined SIPV as any pregnant patient with an identified head, neck, or face injuries categorized as intentional assault. Multivariable logistic regression analysis was performed to assess the association between SIPV and variables of interest. RESULTS: A total of 28,540 pregnant patients presented with traumatic injuries with 530 (.02%) identified as SIPV. Suspected IPV patients were younger (25 vs 27 years, P = .012), more likely to be of Black race (46% vs 28%, P = .002), more likely to be in the lowest income quartile (51% vs 38%, P = .031), less likely to have private insurance (12% vs 34%, P < .001), and have higher rates of substance use disorder (35% vs 18%, P < .001). Black race and history of substance use disorder were associated with increased odds of SIPV-related injuries (odds ratio [OR]: 2.01, interquartile range [IQR]: 1.27-3.16, P = .003 and OR: 2.30, IQR 1.54-3.43, P < .001, respectively). CONCLUSIONS: Our results suggest that there are significant racial and socioeconomic disparities in potential risk for IPV during pregnancy.

Rat hepatitis E virus (Rocahepevirus ratti) exposure in cats and dogs, Hong Kong.

Hepatitis E virus (HEV) variants infecting humans belong to two species: Paslahepevirus balayani (bHEV) and Rocahepevirus ratti (rat hepatitis E virus; rHEV). R. ratti is a ubiquitous rodent pathogen that has recently been recognized to cause hepatitis in humans. Transmission routes of rHEV from rats to humans are currently unknown. In this study, we examined rHEV exposure in cats and dogs to determine if they are potential reservoirs of this emerging human pathogen. Virus-like particle-based IgG enzymatic immunoassays (EIAs) capable of differentiating rHEV & bHEV antibody profiles and rHEV-specific real-time RT-PCR assays were used for this purpose. The EIAs could detect bHEV and rHEV patient-derived IgG spiked in dog and cat sera. Sera from 751 companion dogs and 130 companion cats in Hong Kong were tested with these IgG enzymatic immunoassays (EIAs). Overall, 13/751 (1.7%) dogs and 5/130 (3.8%) cats were sero-reactive to HEV. 9/751 (1.2%) dogs and 2/130 (1.5%) cats tested positive for rHEV IgG, which was further confirmed by rHEV immunoblots. Most rHEV-seropositive animals were from areas in or adjacent to districts reporting human rHEV infection. Neither 881 companion animals nor 652 stray animals carried rHEV RNA in serum or rectal swabs. Therefore, we could not confirm a role for cats and dogs in transmitting rHEV to humans. Further work is required to understand the reasons for low-level seropositivity in these animals.

Development and Evaluation of an In-House Real-Time RT-PCR Targeting nsp10 Gene for SARS-CoV-2 Detection.

The emergence of SARS-CoV-2 mutations poses significant challenges to diagnostic tests, as these mutations can reduce the sensitivity of commonly used RT-PCR assays. Therefore, there is a need to design diagnostic assays with multiple targets to enhance sensitivity. In this study, we identified a novel diagnostic target, the nsp10 gene, using nanopore sequencing. Firstly, we determined the analytical sensitivity and specificity of our COVID-19-nsp10 assay. The COVID-19-nsp10 assay had a limit of detection of 74 copies/mL (95% confidence interval: 48-299 copies/mL) and did not show cross-reactivity with other respiratory viruses. Next, we determined the diagnostic performance of the COVID-19-nsp10 assay using 261 respiratory specimens, including 147 SARS-CoV-2-positive specimens belonging to the ancestral strain and Alpha, Beta, Gamma, Delta, Mu, Eta, Kappa, Theta and Omicron lineages. Using a LightMix E-gene RT-PCR assay as the reference method, the diagnostic sensitivity and specificity of the COVID-19-nsp10 assay were found to be 100%. The median Cp values for the LightMix E-gene RT-PCR and our COVID-19-nsp10 RT-PCR were 22.48 (range: 12.95-36.60) and 25.94 (range 16.37-36.87), respectively. The Cp values of the COVID-19-nsp10 RT-PCR assay correlated well with those of the LightMix E-gene RT-PCR assay (Spearman's ρ = 0.968; p < 0.0001). In conclusion, nsp10 is a suitable target for a SARS-CoV-2 RT-PCR assay.

Post-COVID-19 Pandemic Rebound of Macrolide-Resistant Mycoplasma pneumoniae Infection: A Descriptive Study.

The rebound characteristics of respiratory infections after lifting pandemic control measures were uncertain. From January to November 2023, patients presenting at a teaching hospital were tested for common respiratory viruses and Mycoplasma pneumoniae using a combination of antigen, nucleic acid amplification, and targeted next-generation sequencing (tNGS) tests. The number and rate of positive tests per month, clinical and microbiological characteristics were analyzed. A rapid rebound of SARS-CoV-2 was followed by a slower rebound of M. pneumoniae, with an interval of 5 months between their peaks. The hospitalization rate was higher, with infections caused by respiratory viruses compared to M. pneumoniae. Though the pediatric hospitalization rate of respiratory viruses (66.1%) was higher than that of M. pneumoniae (34.0%), the 4094 cases of M. pneumoniae within 6 months posed a huge burden on healthcare services. Multivariate analysis revealed that M. pneumoniae-infected adults had more fatigue, comorbidities, and higher serum C-reactive protein, whereas children had a higher incidence of other respiratory pathogens detected by tNGS or pathogen-specific PCR, fever, and were more likely to be female. A total of 85% of M. pneumoniae-positive specimens had mutations detected at the 23rRNA gene, with 99.7% showing A2063G mutation. Days to defervescence were longer in those not treated by effective antibiotics and those requiring a change in antibiotic treatment. A delayed but significant rebound of M. pneumoniae was observed after the complete relaxation of pandemic control measures. No unusual, unexplained, or unresponsive cases of respiratory infections which warrant further investigation were identified.

Harnessing Next-Generation Sequencing as a Timely and Accurate Second-Tier Screening Test for Newborn Screening of Inborn Errors of Metabolism.

In this study, we evaluated the implementation of a second-tier genetic screening test using an amplicon-based next-generation sequencing (NGS) panel in our laboratory during the period of 1 September 2021 to 31 August 2022 for the newborn screening (NBS) of six conditions for inborn errors of metabolism: citrullinemia type II (MIM #605814), systemic primary carnitine deficiency (MIM #212140), glutaric acidemia type I (MIM #231670), beta-ketothiolase deficiency (#203750), holocarboxylase synthetase deficiency (MIM #253270) and 3-hydroxy-3-methylglutaryl-CoA lyase deficiency (MIM # 246450). The custom-designed NGS panel can detect sequence variants in the relevant genes and also specifically screen for the presence of the hotspot variant IVS16ins3kb of SLC25A13 by the copy number variant calling algorithm. Genetic second-tier tests were performed for 1.8% of a total of 22,883 NBS samples. The false positive rate for these six conditions after the NGS second-tier test was only 0.017%, and two cases of citrullinemia type II would have been missed as false negatives if only biochemical first-tier testing was performed. The confirmed true positive cases were citrullinemia type II (n = 2) and systemic primary carnitine deficiency (n = 1). The false positives were later confirmed to be carrier of citrullinemia type II (n = 2), carrier of glutaric acidemia type I (n = 1) and carrier of systemic primary carnitine deficiency (n = 1). There were no false negatives reported. The incorporation of a second-tier genetic screening test by NGS greatly enhanced our program's performance with 5-working days turn-around time maintained as before. In addition, early genetic information is available at the time of recall to facilitate better clinical management and genetic counseling.

Investigation of air dispersal during a rhinovirus outbreak in a pediatric intensive care unit.

BACKGROUND: While airborne transmission of rhinovirus is recognized in indoor settings, its role in hospital transmission remains unclear. METHODS: We investigated an outbreak of rhinovirus in a pediatric intensive care unit (PICU) to assess air dispersal. We collected clinical, environmental, and air samples, and staff's surgical masks for viral load and phylogenetic analysis. Hand hygiene compliance and the number of air changes per hour in the PICU were measured. A case-control analysis was performed to identify nosocomial rhinovirus risk factors. RESULTS: Between March 31, 2023, and April 2, 2023, three patients acquired rhinovirus in a cubicle (air changes per hour: 14) of 12-bed PICU. A portable air-cleaning unit was placed promptly. Air samples (72,000 L in 6 hours) from the cohort area, and outer surfaces of staff's masks (n = 8), were rhinovirus RNA-negative. Hand hygiene compliance showed no significant differences (31/34, 91.2% vs 33/37, 89.2%, P = 1) before and during outbreak. Only 1 environmental sample (3.8%) was positive (1.86 × 103 copies/mL). Case-control and next-generation sequencing analysis implicated an infected staff member as the source. CONCLUSIONS: Our findings suggest that air dispersal of rhinovirus was not documented in the well-ventilated PICU during the outbreak. Further research is needed to better understand the dynamics of rhinovirus transmission in health care settings.

Determination of seroprevalence and kinetics of humoral response using mpox virus A29 protein.

BACKGROUND: Mpox virus (MPXV), previously known as monkeypox virus, has spread globally in 2022. An accurate and convenient antibody test is essential for the determination of seroprevalence and for studying immune response after natural infection or vaccination. Most seroprevalence or vaccine studies used either live MPXV (or vaccinia virus [VACV]) or inactivated MPXV (or VACV) culture lysate for serological assays, but MPXV culture can only be performed in biosafety level 3 (BSL-3) facilities. Here, we developed and evaluated an enzyme immunoassay (EIA) based on the MPXV A29 surface envelope protein. METHODS: We compared the specificity of the MPXV A29, VACV A27, and VACV lysate EIA using serum specimens collected prior to the global spread of MPXV. Next, we performed these EIAs for serum specimens collected from two mpox patients and an MVA-BN vaccine recipient. We also assessed the kinetics of plasmblast and MPXV A29-specific B-cell response. RESULTS: Using sera collected from different age groups in Hong Kong, we found that most individuals, including those born before 1981 who have received the smallpox vaccine, tested negative using the MPXV A29 protein. MPXV A29-specific antibody could be detected in the serum of mpox patients and an MVA-BN recipient. In a mpox patient, the frequency of plasmablast and MPXV A29-specific B cell peaked on day 8 post-symptom onset and gradually decreased. Finally, we demonstrated that antibodies against the A29 protein can be used for immunofluorescence staining of MPXV-infected cells. CONCLUSIONS: MPXV A29 protein is suitable for studying the immune response against MPXV infection.

Since early 2022, mpox (monkeypox) has been reported in many countries where the disease is not regularly found to occur. The aim of the study was to develop and evaluate the performance of laboratory assays based on the mpox virus surface protein, named A29. We found our assays could accurately distinguish naturally infected cases from smallpox vaccine recipients as well as those who were neither infected nor vaccinated. Our assays provide a useful tool for studying the host immune response to mpox virus.

Common postbariatric surgery emergencies for the acute care surgeon: What you need to know.

ABSTRACT: The field of bariatric and metabolic surgery has changed rapidly over the past two decades, with an exponential increase in case volumes being performed because of its proven efficacy for morbid obesity and obesity-related comorbidities. Although this increased volume of procedures has been accompanied by significant decrease in postoperative complication rates, there are numerous potential complications after bariatric surgery that may require urgent or emergent surgical evaluation or interventions. Many of these risks extend well beyond the early postoperative period and can present months to years after the index procedure. Acute care surgeons are increasingly covering most or all of the emergency general surgery services at many centers and must be familiar with the numerous bariatric surgical procedures being performed and their individual complication profile to provide optimal care for these frequently challenging patients. This article provides a focused and concise review of the common bariatric procedures being performed, their early and late complication profiles, and a practical guide to the optimal diagnostic evaluations, surgical interventions, and perioperative management options. The author group includes both acute care surgeons and bariatric surgeons with significant experience in the emergency management of the complicated postbariatric surgical patient. LEVEL OF EVIDENCE: Literature Synthesis and Expert Opinion; Level V.

Humoral and cellular immunity against different SARS-CoV-2 variants in patients with chronic kidney disease.

Chronic kidney disease (CKD) patients are at higher risk of severe COVID-19. Humoral and cellular immunity from prior infection or vaccination are important for protection, but the neutralizing antibody (nAb) response against SARS-CoV-2 variants is impaired. We investigated the variant-specific nAb and T cell immunity among CKD patients. Adult CKD patients were recruited between August and October 2022. nAb against the SARS-CoV-2 (ancestral strains and four Omicron sublineages) and T cell response were measured using the live virus neutralization assay and interferon-gamma release assay (IGRA). The correlation between nAb/T-cell response and subsequent infection after recruitment were also determined. Among the 88 recruited patients, 95.5% had prior infection or had completed the primary vaccine series. However, only 77.3% had detectable nAb against at least one SARS-CoV-2 strains, 59.1% tested positive in IGRA, and 52.3% had detectable nAb and tested positive in the IGRA. The nAb geometic mean titers (GMTs) against XBB.1, BA.5 and BA.2.3.20 were significantly lower than those against BA.2 and ancestral strain. Prior SARS-CoV-2 infection was associated with elevated nAb and T cell response. More kidney transplant recipients (KTRs) showed absent nAb and T cell response (36.8% vs. 10.1%), despite a higher prevalence of vaccine booster in this population (94.7% vs. 50.7%). Lower levels of nAb titer and T cell response were significantly associated with subsequent infection. A considerable proportion of CKD patients, especially KTRs, showed absence of humoral and cellular protective immunity against SARS-CoV-2. Strategies to improve immunogenicity in this population are urgently needed.

Antibiotic use in hospitalized patients with COVID-19: a population-based study in Hong Kong.

Background: Hong Kong experienced four epidemic waves caused by the ancestral strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2020-2021 and a large Omicron wave in 2022. Few studies have assessed antibacterial prescribing for coronavirus disease 2019 (COVID-19) inpatients throughout the pandemic. Objectives: To describe inpatient antibacterial prescribing and explore factors associated with their prescription. Methods: Electronic health records of patients with COVID-19 admitted to public hospitals in Hong Kong from 21 January 2020 to 30 September 2022 were used to assess the prevalence and rates of inpatient antibacterial drug use (days of therapy/1,000 patient days [DOT/1,000 PD]). We used multivariable logistic regression to investigate potential associations between patients' baseline characteristics and disease severity and prescription of an antibacterial drug during hospital admission. Results: Among 65,810 inpatients with COVID-19, 54.0% were prescribed antibacterial drugs (550.5 DOT/1,000 PD). Compared to waves 1-2 (46.7%; 246.9 DOT/1,000 PD), the prescriptions were lowest during wave 4 (28.0%; 246.9; odds ratio (OR): 0.39, 95% CI: 0.31-0.49) and peaked in early wave 5 (64.6%; 661.2; 0.82, 0.65-1.03). Older age (≥80 years: OR 2.66, 95% CI, 2.49-2.85; 60-79 years: 1.59, 1.51-1.69, compared with 20-59 years), more severe disease (fatal: 3.64, 3.2-4.16; critical: 2.56, 2.14-3.06, compared with severe), and COVID-19 vaccine doses (two doses: 0.74, 0.69-0.78; three doses: 0.69, 0.64-0.74; four doses: 0.52, 0.44-0.62, compared with unvaccinated) were associated with inpatient antibacterial drug use. Conclusions: Antibacterial prescribing changed over time for hospitalized patients with confirmed COVID-19 and was potentially related to patients' demographics, medical conditions, and COVID-19 vaccination status as well as healthcare capacity during epidemic waves.

Prevalence and Characteristics of Invasive Staphylococcus argenteus among Patients with Bacteremia in Hong Kong.

Staphylococcus argenteus is a novel Staphylococcus species derived from Staphylococcus aureus. Information on the prevalence and genetic characteristics of invasive S. argenteus in Asia is limited. In this study, 275 invasive S. aureus complex strains were retrieved from blood culture specimens in Hong Kong and re-analyzed using MALDI-TOF mass spectrometry and an in-house multiplex real-time PCR for S. argenteus. The prevalence of invasive S. argenteus in Hong Kong was found to be 4.0% (11/275). These strains were primarily susceptible to commonly used antibiotics, except penicillin. Whole-genome sequencing revealed the circulation of three S. argenteus genotypes (ST-2250, ST-1223, and ST-2854) in Hong Kong, with ST-2250 and ST-1223 being the predominant genotypes. The local ST-2250 and ST-1223 strains showed close phylogenetic relationships with isolates from mainland China. Antimicrobial-resistant genes (fosB, tet-38, mepA, blaI, blaZ) could be found in nearly all local S. argenteus strains. The ST-1223 and ST-2250 genotypes carried multiple staphylococcal enterotoxin genes that could cause food poisoning and toxic shock syndrome. The CRISPR/Cas locus was observed only in the ST-2250 strains. This study provides the first report on the molecular epidemiology of invasive S. argenteus in Hong Kong, and further analysis is needed to understand its transmission reservoir.

An Australian convective wind gust climatology using Bayesian hierarchical modelling.

To quantify the hazard or risks associated with severe convective wind gusts, it is necessary to have a reliable and spatially complete climatology of these events. The coupling of observational and global reanalysis (ERA-Interim) data over the period 2005-2015 is used here to facilitate the development of a spatially complete convective wind gust climatology for Australia. This is done through the development of Bayesian Hierarchical models that use both weather station-based wind gust observations and seasonally averaged severe weather indices (SWI), calculated using reanalysis data, to estimate seasonal gust frequencies across the country while correcting for observational biases specifically, the sparse observational network to record events. Different SWI combinations were found to explain event counts for different seasons. For example, combinations of Lifted Index and low level wind shear were found to generate the best results for autumn and winter. While for spring and summer, the composite Microburst Index and the combination of most unstable CAPE and 0-1 km wind shear were found to be most successful. Results from these models showed a minimum in event counts during the winter months, with events that do occur mainly doing so along the southwest coast of Western Australia or along the coasts of Tasmania and Victoria. Summer is shown to have the largest event counts across the country, with the largest number of gusts occurring in northern Western Australia extending east into the Northern Territory with another maximum over northeast New South Wales. Similar trends were found with an extended application of the models to the period 1979-2015 when utilizing only reanalysis data as input. This implementation of the models highlights the versatility of the Bayesian hierarchical modelling approach and its ability, when trained, to be used in the absence of observations.

An immunoassay system to investigate epidemiology of Rocahepevirus ratti (rat hepatitis E virus) infection in humans.

Background & Aims: Rat hepatitis E virus (Rocahepevirus ratti; HEV-C1) is an emerging cause of hepatitis E that is divergent from conventional human-infecting HEV variants (Paslahepevirus balayani; HEV-A). Validated serological assays for HEV-C1 are lacking. We aimed to develop a parallel enzymatic immunoassay (EIA) system that identifies individuals with HEV-C1 exposure. We also aimed to conduct the first HEV-C1 seroprevalence study in humans using this validated EIA system. Methods: Expressed HEV-A (HEV-A4 p239) and HEV-C1 (HEV-C1 p241) peptides were characterised. Blood samples were simultaneously tested in HEV-A4 p239 and HEV-C1 p241 IgG EIAs. An optical density (OD) cut-off-based interpretation algorithm for identifying samples seropositive for HEV-A or HEV-C1 was validated using RT-PCR-positive infection sera. This algorithm was used to measure HEV-C1 seroprevalence in 599 solid organ transplant recipients and 599 age-matched immunocompetent individuals. Results: Both peptides formed virus-like particles. When run in HEV-A4 p239 and HEV-C1 p241 EIAs, HEV-A and HEV-C1 RT-PCR-positive samples formed distinct clusters with minimal overlap in a two-dimensional plot of optical density values. The final EIA interpretation algorithm showed high agreement with RT-PCR results (Cohen's κ = 0.959) and was able to differentiate HEV-A and HEV-C1 infection sera with an accuracy of 94.2% (95% CI: 85.8-98.4%). HEV-C1 IgG seroprevalence was 7/599 (1.2%) among solid organ transplant recipients and 4/599 (0.7%) among immunocompetent individuals. Five of 11 (45.5%) of these patients had history of transient hepatitis of unknown cause. Conclusions: HEV-C1 exposure was identified in 11/1198 (0.92%) individuals in Hong Kong indicating endemic exposure. This is the first estimate of HEV-C1 seroprevalence in humans. The parallel IgG EIA algorithm is a valuable tool for investigating epidemiology and risk factors for HEV-C1 infection. Impact and Implications: Rat hepatitis E virus has recently been discovered to infect humans, but antibody tests for this infection are lacking, making it difficult to gauge how common this infection is. We developed an antibody test algorithm that can identify individuals with past rat hepatitis E virus exposure. We used this algorithm to estimate rat hepatitis E exposure rates in humans in Hong Kong and found that approximately 1% of all tested people had been exposed to this virus previously.

Resuscitative Endovascular Balloon Occlusion of the Aorta for Nontraumatic Gastrointestinal Hemorrhage in the US.

This cohort study describes the use of and outcomes for resuscitative endovascular balloon occlusion of the aorta for managing nontraumatic gastrointestinal bleeding.