Effects of surface-attached durations, nutrients, and relative humidity on the resuspension of bacteria during human walking.

Resuspension caused by human walking activities is an important source of indoor bioaerosols and has been associated with health effects such as allergies and asthma. However, it is unknown whether inhalation of resuspended bioaerosols is an important exposure pathway for airborne infection. Also, crucial factors influencing the resuspension of settled microbes have not been quantified. In this study, we experimentally investigated the resuspension of culturable bacteria from human-stepping on polyvinyl chloride (PVC) flooring under different conditions. We determined the bacterial resuspension emission factor (ER), a normalized resuspension parameter for the ratio of resuspended mass in the air to the mass of settled particles, for two common bacteria, Escherichia coli and Salmonella enterica. The investigation involved varying factors such as microbial surface-attached durations (0, 1, 2, and 3 days), the absence or presence of nutrients on flooring surfaces, and changes in relative humidity (RH) (35%, 65%, and 85%). The results showed that, in the absence of nutrients, the highest ER values for E. coli and S. enterica were 3.8 × 10-5 ± 5.2 × 10-6 and 5.3 × 10-5 ± 6.0 × 10-6, respectively, associated with surface-attached duration of 0 days. As the surface-attached duration increased from 0 to 3 days, ER values decreased by 92% and 84% for E. coli and S. enterica, respectively. In addition, we observed that ER values decreased with the increasing RH, which is consistent with particle adhesion theory. This research offers valuable insights into microbial resuspension during human walking activities and holds the potential for assisting in the assessment and estimation of risks related to human exposure to bioaerosols.

Fracture Risk in Pediatric Patients With MEN2B.

CONTEXT: The skeletal phenotype of patients with MEN2B has been described but fracture risk in these patients has not yet been evaluated. OBJECTIVE: This work aims to better delineate fracture risk in patients with multiple endocrine neoplasia type 2B (MEN2B). METHODS: This case series with chart review was conducted at the National Institutes of Health, Pediatric Oncology Branch. A total of 48 patients with MEN2B were identified, with an age range of 5 to 36 years, median of 19; 24 of 48 (50%) patients were female. Medical records, demographic information, available imaging, and laboratory results were reviewed. History up to age 19 was included in the statistical analyses. RESULTS: Of the 48 patients with MEN2B, 20 patients experienced at least one fracture. The majority (n = 18) experienced their first fracture at or before age 19. The observed frequency of fracture occurrence throughout childhood (0-19 years) was 38%, with very little difference between males and females. This frequency is higher than the 9.47 to 36.1 fractures per 1000 persons per year that has been reported in healthy pediatric cohorts in the United States. Less common sites of fracture including vertebral compression fracture and pelvic fractures were observed in patients with MEN2B. CONCLUSION: In this group of patients with MEN2B, there was an increased overall risk of fracture compared to general pediatric cohorts in the United States. Less common sites of fracture were also observed. This suggests a possible effect of an activating RET mutation on bone physiology and warrants further investigation.

Microfluidic particle dam for direct visualization of SARS-CoV-2 antibody levels in COVID-19 vaccinees.

Various COVID-19 vaccines are currently deployed, but their immunization varies and decays with time. Antibody level is a potent correlate to immune protection, but its quantitation relies on intensive laboratory techniques. Here, we report a decentralized, instrument-free microfluidic device that directly visualizes SARS-CoV-2 antibody levels. Magnetic microparticles (MMPs) and polystyrene microparticles (PMPs) can bind to SARS-CoV-2 antibodies simultaneously. In a microfluidic chip, this binding reduces the incidence of free PMPs escaping from magnetic separation and shortens PMP accumulation length at a particle dam. This visual quantitative result enables use in either sensitive mode [limit of detection (LOD): 13.3 ng/ml; sample-to-answer time: 70 min] or rapid mode (LOD: 57.8 ng/ml; sample-to-answer time: 20 min) and closely agrees with the gold standard enzyme-linked immunosorbent assay. Trials on 91 vaccinees revealed higher antibody levels in mRNA vaccinees than in inactivated vaccinees and their decay in 45 days, demonstrating the need for point-of-care devices to monitor immune protection.

Repurposing of Miltefosine as an Adjuvant for Influenza Vaccine.

We previously reported that topical imiquimod can improve the immunogenicity of the influenza vaccine. This study investigated another FDA-approved drug, miltefosine (MTF), as a vaccine adjuvant. Mice immunized with an influenza vaccine with or without MTF adjuvant were challenged by a lethal dose of influenza virus 3 or 7 days after vaccination. Survival, body weight, antibody response, histopathological changes, viral loads, cytokine levels, and T cell frequencies were compared. The MTF-adjuvanted vaccine (MTF-VAC) group had a significantly better survival rate than the vaccine-only (VAC) group, when administered 3 days (80% vs. 26.7%, p = 0.0063) or 7 days (96% vs. 65%, p = 0.0041) before influenza virus challenge. Lung damage was significantly ameliorated in the MTF-VAC group. Antibody response was significantly augmented in the MTF-VAC group against both homologous and heterologous influenza strains. There was a greater T follicular helper cell (TFH) response and an enhanced germinal center (GC) reaction in the MTF-VAC group. MTF-VAC also induced both TH1 and TH2 antigen-specific cytokine responses. MTF improved the efficacy of the influenza vaccine against homologous and heterologous viruses by improving the TFH and antibody responses. Miltefosine may also be used for other vaccines, including the upcoming vaccines for COVID-19.

A review of the manufacturing process and infection rate of 3D-printed models and guides sterilized by hydrogen peroxide plasma and utilized intra-operatively.

3D printing in the context of medical application can allow for visualization of patient-specific anatomy to facilitate surgical planning and execution. Intra-operative usage of models and guides allows for real time feedback but ensuring sterility is essential to prevent infection. The additive manufacturing process restricts options for sterilisation owing to temperature sensitivity of thermoplastics utilised for fabrication. Here, we review one of the largest single cohorts of 3D models and guides constructed from Acrylonitrile butadiene styrene (ABS) and utilized intra-operatively, following terminal sterilization with hydrogen peroxide plasma. We describe our work flow from initial software rendering to printing, sterilization, and on-table application with the objective of demonstrating that our process is safe and can be implemented elsewhere. Overall, 7% (8/114 patients) of patients developed a surgical site infection, which was not elevated in comparison to related studies utilizing traditional surgical methods. Prolonged operation time with an associated increase in surgical complexity was identified to be a risk factor for infection. Low temperature plasma-based sterilization depends upon sufficient permeation and contact with surfaces which are a particular challenge when our 3D-printouts contain diffusion-restricted luminal spaces as well as hollows. Application of printouts as guides for power tools may further expose these regions to sterile bodily tissues and result in generation of debris. With each printout being a bespoke medical device, it is important that the multidisciplinary team involved in production and application understand potential pitfalls to ensuring sterility as to minimize infection risk.

Risk of cutaneous herpes zoster in patients with spondyloarthritis treated with conventional and biologic disease-modifying antirheumatic drugs.

OBJECTIVES: To investigate the risk of cutaneous herpes zoster (HZ) in spondyloarthritis (SpA) compared with that in rheumatoid arthritis (RA), and in disease-modifying antirheumatic drugs (DMARDs) used in SpA. METHOD: A total of 727 patients with an expert diagnosis of SpA were identified retrospectively from four rheumatology centers in Hong Kong. Electronic medical records from 1995 to 2018 were reviewed for incidence of cutaneous HZ and demographic data including age, sex, comorbidities, smoking and drinking status. DMARDs used included sulphasalazine, methotrexate, leflunomide, steroids, etanercept, infliximab, adalimumab, golimumab, secukinumab and ustekinumab. Cox regression models were used to evaluate hazard ratios (HRs) of different DMARDs in patients with SpA. Propensity score was used for matching and comparison with 857 patients with RA. RESULTS: There were 23 cases of cutaneous HZ in patients with SpA and 59 cases in patients with RA. Among patients with SpA, 7 cases of cutaneous HZ may be attributed to sulfasalazine treatment, 7 to methotrexate, 2 to leflunomide, 2 to infliximab, 1 to etanercept, 2 to adalimumab, and 1 to secukinumab. Risks of cutaneous HZ were the same in SpA (stratified HR 0.97; 95% CI 0.58; 1.61; P = .89) and RA. Methotrexate (adjusted HR 3.47; 95% CI 1.25; 9.63; P = .02) and infliximab (adjusted HR 10.67; 95% CI 1.37; 82.88; P = .02) were found to be associated with HZ after adjustments for traditional risk factors. CONCLUSION: Risk of cutaneous HZ in SpA was not lower than in RA. Methotrexate and infliximab were associated with cutaneous HZ in SpA.

Pneumocystis jirovecii-related spontaneous pneumothorax, pneumomediastinum and subcutaneous emphysema in a liver transplant recipient: a case report.

BACKGROUND: Pneumocystis pneumonia (PCP) is a common opportunistic infection caused by Pneumocystis jirovecii. Its incidence at 2 years or more after liver transplant (LT) is < 0.1%. PCP-related spontaneous pneumothorax and/or pneumomediastinum is rare in patients without the human immunodeficiency virus, with an incidence of 0.4-4%. CASE PRESENTATION: A 65-year-old woman who had split-graft deceased-donor LT for primary biliary cirrhosis developed fever, dyspnea and dry coughing at 25 months after transplant. Her immunosuppressants included tacrolimus, mycophenolate mofetil, and prednisolone. PCP infection was confirmed by molecular detection of Pneumocystis jirovecii,in bronchoalveolar lavage. On day-10 trimethoprim-sulphamethoxazole, her chest X-ray showed subcutaneous emphysema bilaterally, right pneumothorax and pneumomediastinum. Computed tomography of the thorax confirmed the presence of right pneumothorax, pneumomediastinum and subcutaneous emphysema. She was managed with 7-day right-sided chest drain and a 21-day course of trimethoprim-sulphamethoxazole before discharge. CONCLUSION: Longer period of PCP prophylaxis should be considered in patients who have a higher risk compared to general LT patients. High index of clinical suspicion, prompt diagnosis and treatment with ongoing patient reassessment to detect and exclude rare, potentially fatal but treatable complications are essential, especially when clinical deterioration has developed.

Acute hepatitis E virus infection causing acute liver failure requiring living-donor liver transplantation in a non-pregnant immunocompetent woman.

We report a rare case of acute liver failure from acute hepatitis E virus (HEV) in a non-pregnant woman without comorbidities who survived after liver transplantation. The source was likely consumption of partially cooked pig liver. HEV genotype 3 is the second most common genotype causing acute hepatitis E in developed countries. Fulminant hepatitis E rarely occurs without a risk factor, as in our patient. Vigilant monitoring for chronic hepatitis E in post-transplant immunocompromised patients is needed.

Sequential Mycoplasma pneumoniae pneumonia and Chromobacterium violaceum skin abscess in a pediatric patient.

Mycoplasma pneumoniae is a common atypical respiratory pathogen causing community-acquired pneumonia in children. Co-infection with other respiratory viruses is common in pediatric patients but super-infection with bacteria other than Streptococcus pneumoniae and Haemophilus influenzae is rare. The first case of Chromobacterium violaceum infection incubated during and manifested after pneumonia caused by Mycoplasma pneumoniae in a 12-month old girl without any known history of immunodeficiency is here reported. The patient developed fever with redness and swelling over the middle phalanx of the right hand index finger which progressed to the formation of skin abscess. Following a course of intravenous meropenem and surgical drainage of the skin abscess, the patient fully recovered and was discharged.

Lipid metabolites as potential diagnostic and prognostic biomarkers for acute community acquired pneumonia.

Early diagnosis of acute community-acquired pneumonia (CAP) is important in patient triage and treatment decisions. To identify biomarkers that distinguish patients with CAP from non-CAP controls, we conducted an untargeted global metabolome analysis for plasma samples from 142 patients with CAP (CAP cases) and 97 without CAP (non-CAP controls). Thirteen lipid metabolites could discriminate between CAP cases and non-CAP controls with area-under-the-receiver-operating-characteristic curve of >0.8 (P ≤ 10(-9)). The levels of glycosphingolipids, sphingomyelins, lysophosphatidylcholines and L-palmitoylcarnitine were higher, while the levels of lysophosphatidylethanolamines were lower in the CAP cases than those in non-CAP controls. All 13 metabolites could distinguish CAP cases from the non-infection, extrapulmonary infection and non-CAP respiratory tract infection subgroups. The levels of trihexosylceramide (d18:1/16:0) were higher, while the levels of lysophosphatidylethanolamines were lower, in the fatal than those of non-fatal CAP cases. Our findings suggest that lipid metabolites are potential diagnostic and prognostic biomarkers for CAP.

Tracking and Resolving CT Dose Metric Outliers Using Root-Cause Analysis.

PURPOSE: The aim of this study was to examine the frequency and type of outlier dose metrics for three common CT examination types on the basis of a root-cause analysis (RCA) approach. METHODS: Institutional review board approval was obtained for this retrospective observational study. The requirement to obtain informed consent was waived. Between January 2010 and December 2013, radiation dose metric data from 34,615 CT examinations, including 26,878 routine noncontrast CT head, 2,992 CT pulmonary angiographic (CTPA), and 4,745 renal colic examinations, were extracted from a radiation dose index monitoring database and manually cleaned. Dose outliers were identified on the basis of the statistical distribution of volumetric CT dose index and dose-length product for each examination type; values higher than the 99th percentile and less than the 1st percentile were flagged for RCA. RESULTS: There were 397 noncontrast CT head, 52 CTPA, and 80 renal colic outliers. Root causes for high-outlier examinations included repeat examinations due to patient motion (n = 122 [31%]), modified protocols mislabeled as "routine" (n = 69 [18%]), higher dose examinations for patients with large body habitus (n = 27 [7%]), repeat examinations due to technical artifacts (n = 20 [5%]), and repeat examinations due to suboptimal contrast timing (CTPA examinations) (n = 18 [5%]). Root causes for low-outlier examinations included low-dose protocols (n = 112 [29%]) and aborted examinations (n = 8 [2%]). On the basis of examination frequency over a 3-month period, the 90th and 10th percentile values were set in the radiation dose index monitoring database as thresholds for sending notifications to staff members responsible for outlier investigations. CONCLUSIONS: Systematic RCA of dose outliers identifies sources of variation and dose excess and pinpoints specific protocol and technical shortcomings for corrective action.

Examining the Role of the Human Hippocampus in Approach-Avoidance Decision Making Using a Novel Conflict Paradigm and Multivariate Functional Magnetic Resonance Imaging.

Rodent models of anxiety have implicated the ventral hippocampus in approach-avoidance conflict processing. Few studies have, however, examined whether the human hippocampus plays a similar role. We developed a novel decision-making paradigm to examine neural activity when participants made approach/avoidance decisions under conditions of high or absent approach-avoidance conflict. Critically, our task required participants to learn the associated reward/punishment values of previously neutral stimuli and controlled for mnemonic and spatial processing demands, both important issues given approach-avoidance behavior in humans is less tied to predation and foraging compared to rodents. Participants played a points-based game where they first attempted to maximize their score by determining which of a series of previously neutral image pairs should be approached or avoided. During functional magnetic resonance imaging, participants were then presented with novel pairings of these images. These pairings consisted of images of congruent or opposing learned valences, the latter creating conditions of high approach-avoidance conflict. A data-driven partial least squares multivariate analysis revealed two reliable patterns of activity, each revealing differential activity in the anterior hippocampus, the homolog of the rodent ventral hippocampus. The first was associated with greater hippocampal involvement during trials with high as opposed to no approach-avoidance conflict, regardless of approach or avoidance behavior. The second pattern encompassed greater hippocampal activity in a more anterior aspect during approach compared to avoid responses, for conflict and no-conflict conditions. Multivoxel pattern classification analyses yielded converging findings, underlining a role of the anterior hippocampus in approach-avoidance conflict decision making. SIGNIFICANCE STATEMENT: Approach-avoidance conflict has been linked to anxiety and occurs when a stimulus or situation is associated with reward and punishment. Although rodent work has implicated the hippocampus in approach-avoidance conflict processing, there is limited data on whether this role applies to learned, as opposed to innate, incentive values, and whether the human hippocampus plays a similar role. Using functional neuroimaging with a novel decision-making task that controlled for perceptual and mnemonic processing, we found that the human hippocampus was significantly active when approach-avoidance conflict was present for stimuli with learned incentive values. These findings demonstrate a role for the human hippocampus in approach-avoidance decision making that cannot be explained easily by hippocampal-dependent long-term memory or spatial cognition.

Metabolomic Profiling of Plasma from Patients with Tuberculosis by Use of Untargeted Mass Spectrometry Reveals Novel Biomarkers for Diagnosis.

Although tuberculosis (TB) is a reemerging disease that affects people in developing countries and immunocompromised populations in developed countries, the current diagnostic methods are far from optimal. Metabolomics is increasingly being used for studies on infectious diseases. We performed metabolome profiling of plasma samples to identify potential biomarkers for diagnosing TB. We compared the plasma metabolome profiles of TB patients (n = 46) with those of community-acquired pneumonia (CAP) patients (n = 30) and controls without active infection (n = 30) using ultrahigh-performance liquid chromatography-electrospray ionization-quadrupole time of flight mass spectrometry (UHPLC-ESI-QTOFMS). Using multivariate and univariate analyses, four metabolites, 12R-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid [12(R)-HETE], ceramide (d18:1/16:0), cholesterol sulfate, and 4α-formyl-4ß-methyl-5α-cholesta-8-en-3ß-ol, were identified and found to have significantly higher levels in TB patients than those in CAP patients and controls. In a comparison of TB patients and controls, the four metabolites demonstrated area under the receiver operating characteristic curve (AUC) values of 0.914, 0.912, 0.905, and 0.856, sensitivities of 84.8%, 84.8%, 87.0%, and 89.1%, specificities of 90.0%, 86.7%, 86.7%, and 80.0%, and fold changes of 4.19, 26.15, 6.09, and 1.83, respectively. In a comparison of TB and CAP patients, the four metabolites demonstrated AUC values of 0.793, 0.717, 0.802, and 0.894, sensitivities of 89.1%, 71.7%, 80.4%, and 84.8%, specificities of 63.3%, 66.7%, 70.0%, and 83.3%, and fold changes of 4.69, 3.82, 3.75, and 2.16, respectively. 4α-Formyl-4ß-methyl-5α-cholesta-8-en-3ß-ol combined with 12(R)-HETE or cholesterol sulfate offered ≥70% sensitivity and ≥90% specificity for differentiating TB patients from controls or CAP patients. These novel plasma biomarkers, especially 12(R)-HETE and 4α-formyl-4ß-methyl-5α-cholesta-8-en-3ß-ol, alone or in combination, are potentially useful for rapid and noninvasive diagnosis of TB. The present findings may offer insights into the pathogenesis and host response in TB.

Identifying Institutional Diagnostic Reference Levels for CT with Radiation Dose Index Monitoring Software.

PURPOSE: To retrospectively evaluate radiation optimization efforts over 4 years for three computed tomography (CT) protocols and to determine institutional (local) diagnostic reference levels for prospective tracking by using automated radiation dose index monitoring software. MATERIALS AND METHODS: Approval for this retrospective observational study was obtained from the hospital research ethics board, and the need to obtain informed consent was waived. The study followed a 48-month radiation dose optimization effort in a large academic inner-city trauma and quaternary referral center. Exposure according to equipment, protocol, and year (2010-2013) for adult patients was determined for routine unenhanced head CT examinations, CT pulmonary angiography examinations, and CT examinations for renal colic. Mean exposure (as volume CT dose index [CTDIvol] and dose-length product [DLP]) was averaged to establish local diagnostic reference levels. Means and 75th percentiles for 2013 were compared with findings from surveys in Canada and diagnostic reference levels for similar protocol types internationally. Student t tests were performed to assess significance between annual means, and χ(2) tests were performed for changes in categoric variables. RESULTS: There were 36 996 examinations in 25 234 patients. There was an average exposure reduction of 22% for CTDIvol and 13% for DLP from 2010 to 2013. In 2013, mean CTDIvol for routine head examinations was 50.8 mGy ± 3.7 (standard deviation), 11.8 mGy ± 5.6 for CT pulmonary angiography examinations, and 10.2 mGy ± 4.2 for renal colic CT examinations, while mean DLP was 805.7 mGy · cm ± 124.3, 432.8 mGy-cm ± 219.9, and 469.4 mGy · cm ± 209.2, respectively. The mean CTDIvol and DLP in 2013 were at or close to identified reference values; however, additional optimization is required to reach "as low as reasonably achievable" values for all examinations. CONCLUSION: Automated methods of radiation dose data collection permit a detailed analysis of radiation dose according to protocol and equipment over time. Radiation dose optimization measures were effective, but their full value may be realized only with changes in internal processes and real-time, prospective data monitoring and analysis.

Circulating cytomegalic cells in a patient with advanced HIV presenting with cytomegalovirus rhinosinusitis.

We report a patient with newly diagnosed late-stage HIV presenting with fever, rhinosinusitis and cognitive impairment. Analysis of cerebrospinal fluid and nasal turbinate tissue confirmed cytomegalovirus (CMV) infection. CMV pp65 antigen assay conducted on peripheral blood leukocytes revealed large CMV infected mononuclear cells (diameter ∼ 50 µm) with an unusual cytoplasmic pattern of pp65 staining. These large cells were also seen in buffy coat Wright's stained smears; their size, morphology and pp65 antigen uptake pattern were consistent with CMV infected cytomegalic endothelial cells. While CMV sinus infections are occasionally encountered in AIDS patients, this is the first report to document CMV infection of the nasal mucosa with secondary sinusitis and chronic suppurative otitis media. Furthermore, the detection of circulating cytomegalic cells is described--a rare finding with pathological and clinical significance in immunocompromised patients with CMV disease.

Fatal empyema thoracis caused by Schizophyllum commune with cross-reactive cryptococcal antigenemia.

We report a fatal case of Schizophyllum commune empyema thoracis with cross-reactive cryptococcal antigenemia. In vitro testing confirmed the ability of the fungus to cause a positive cryptococcal antigen latex agglutination system (CALAS) test result. Such a result may lead to delay in diagnosis and treatment, as most strains of S. commune are resistant to fluconazole.

Haemophagocytic lymphohistiocytosis: an uncommon clinical presentation of tuberculosis.

Secondary haemophagocytic lymphohistiocytosis is a rare but fatal complication of tuberculosis. We describe two cases, and review the local and international experience on the management of this clinical entity. Prompt treatment with anti-tuberculous drugs forms the cornerstone of therapeutic success.

Extensive contact tracing and screening to control the spread of vancomycin-resistant Enterococcus faecium ST414 in Hong Kong.

BACKGROUND: Proactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci (VRE) endemicity is not yet established, contact tracing and screening, together with other infection control measures are essential in limiting intra- and inter-hospital transmission. The objective of this study was to illustrate the control measures used to eradicate a VRE outbreak in a hospital network in Hong Kong. METHODS: We described an outbreak of VRE in a healthcare region in Hong Kong, involving a University affiliated hospital and a convalescent hospital of 1600 and 550 beds respectively. Computer-assisted analysis was utilized to facilitate contact tracing, followed by VRE screening using chromogenic agar. Multi-locus sequence typing (MLST) was performed to assess the clonality of the VRE strains isolated. A case-control study was conducted to identify the risk factors for nosocomial acquisition of VRE. RESULTS: Between November 26 and December 17, 2011, 11 patients (1 exogenous case and 10 secondary cases) in two hospitals with VRE colonization were detected during our outbreak investigation and screening for 361 contact patients, resulting in a clinical attack rate of 2.8% (10/361). There were 8 males and 3 females with a median age of 78 years (range, 40 - 87 years). MLST confirmed sequence type ST414 in all isolates. Case-control analysis demonstrated that VRE positive cases had a significantly longer cumulative length of stay (P < 0.001), a higher proportion with chronic cerebral and cardiopulmonary conditions (P = 0.001), underlying malignancies (P < 0.001), and presence of urinary catheter (P < 0.001), wound or ulcer (P < 0.001), and a greater proportion of these patients were receiving ß-lactam/ß-lactamase inhibitors (P = 0.009), carbapenem group (P < 0.001), fluoroquinolones (P = 0.003), or vancomycin (P = 0.001) when compared with the controls. CONCLUSION: Extensive contact tracing and screening with a "search-and-confine" strategy was a successful tool for outbreak control in our healthcare region.

High mortality associated with Catabacter hongkongensis bacteremia.

Catabacter hongkongensis is a recently described catalase-positive, motile, anaerobic, nonsporulating, Gram-positive coccobacillus that was first isolated from blood cultures of four patients from Hong Kong and Canada. Although DNA sequences representing C. hongkongensis have been detected in environmental sources, only one additional case of human infection has been reported, in France. We describe five cases of C. hongkongensis bacteremia in Hong Kong, two presenting with sepsis, one with acute gangrenous perforated appendicitis, one with acute calculous cholecystitis, and one with infected carcinoma of colon. Three patients, with gastrointestinal malignancy, died during admission. All five isolates were catalase positive, motile, and negative for indole production and nitrate reduction and produced acid from arabinose, glucose, mannose, and xylose. They were unambiguously identified as C. hongkongensis by 16S rRNA gene analysis. Of the total of 10 reported cases of C. hongkongensis bacteremia in the literature and this study, most patients had underlying diseases, while two cases occurred in healthy young individuals with acute appendicitis. Six patients presented with infections associated with either the gastrointestinal or biliary tract, supporting the gastrointestinal tract as the source of bacteremia. C. hongkongensis bacteremia is associated with a poor prognosis, with a high mortality of 50% among reported cases, especially in patients with advanced malignancies. All reported isolates were susceptible to metronidazole. Identification of more C. hongkongensis isolates by 16S rRNA gene sequencing will help better define its epidemiology and pathogenesis.

Clinical and virological factors associated with viremia in pandemic influenza A/H1N1/2009 virus infection.

BACKGROUND: Positive detection of viral RNA in blood and other non-respiratory specimens occurs in severe human influenza A/H5N1 viral infection but is not known to occur commonly in seasonal human influenza infection. Recently, viral RNA was detected in the blood of patients suffering from severe pandemic influenza A/H1N1/2009 viral infection, although the significance of viremia had not been previously studied. Our study aims to explore the clinical and virological factors associated with pandemic influenza A/H1N1/2009 viremia and to determine its clinical significance. METHODOLOGY/PRINCIPAL FINDINGS: Clinical data of patients admitted to hospitals in Hong Kong between May 2009 and April 2010 and tested positive for pandemic influenza A/H1N1/2009 was collected. Viral RNA was detected by reverse-transcription polymerase chain reactions (RT-PCR) targeting the matrix (M) and HA genes of pandemic influenza A/H1N1/2009 virus from the following specimens: nasopharyngeal aspirate (NPA), endotracheal aspirate (ETA), blood, stool and rectal swab. Stool and/ or rectal swab was obtained only if the patient complained of any gastrointestinal symptoms. A total of 139 patients were included in the study, with viral RNA being detected in the blood of 14 patients by RT-PCR. The occurrence of viremia was strongly associated with a severe clinical presentation and a higher mortality rate, although the latter association was not statistically significant. D222G/N quasispecies were observed in 90% of the blood samples. CONCLUSION: Presence of pandemic influenza A/H1N1/2009 viremia is an indicator of disease severity and strongly associated with D222G/N mutation in the viral hemagglutinin protein.