No abstract

Viral shedding profile of infections caused by the pandemic H1N1 2009 influenza A virus has not been reported. The aim of this study was to determine the viral load in different body sites. Viral loads of pandemic H1N1 virus in respiratory specimens, stool, urine, and serum were determined by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Respiratory specimens from patients with seasonal influenza were used as historical controls. Initial pre-treatment viral load were compared between these two groups. Serial respiratory specimens from patients with pandemic H1N1 virus infection were obtained for analysis of viral dynamics. Twenty-two pandemic H1N1 cases and 44 seasonal influenza historical controls were included. The mean initial viral load before oseltamivir therapy was 1.84 x 10(8) copies/ml for pandemic H1N1 virus compared with 3.28 x 10(8) copies/ml in seasonal influenza historical controls (P = 0.085). Among patients with pandemic H1N1 virus infection, peak viral load occurred on the day of onset of symptoms, and declined gradually afterwards, with no virus being detectable in respiratory specimens by RT-PCR 8 days and by culture 5 days after the onset of symptoms respectively, except in one patient. Pandemic H1N1 virus was detected in stool and in urine from 4/9 and 1/14 patients, respectively. Viral culture was also positive from the stool sample with the highest viral load. Younger age was associated with prolonged shedding in the respiratory tract and higher viral load in the stool. Data from this quantitative analysis of viral shedding may have implications for formulating infection control measures.

Sinopulmonary and rhinocerebral zygomycosis has been increasingly found in patients with hematological malignancies and bone marrow transplantation, but intestinal zygomycosis remains very rare in the literature. We investigated an outbreak of intestinal infection due to Rhizopus microsporus in 12 patients on treatment for hematological malignancies over a period of 6 months in a teaching hospital. The intake of allopurinol during hospitalization (P < 0.001) and that of commercially packaged ready-to-eat food items in the preceding 2 weeks (P < 0.001) were found to be independently significant risk factors for the development of intestinal zygomycosis. A total of 709 specimens, including 378 environmental and air samples, 181 food samples, and 150 drug samples, were taken for fungal culture. Among them, 16 samples of allopurinol tablets, 3 prepackaged ready-to-eat food items, and 1 pair of wooden chopsticks were positive for Rhizopus microsporus, which was confirmed by ITS1-5.8S-ITS2 rRNA gene cluster (internal transcribed spacer [ITS]) sequencing. The mean viable fungal counts of allopurinol obtained from wards and pharmacy were 4.22 ؋ 10 3 CFU/g of tablet (range, 3.07 ؋ 10 3 to 5.48 ؋ 10 3 ) and 3.24 ؋ 10 3 CFU/g of tablet (range, 2.68 ؋ 10 3 to 3.72 ؋ 10 3 ), respectively, which were much higher than the mean count of 2 ؋ 10 2 CFU/g of food. Phylogenetic analysis by ITS sequencing showed multiple clones from isolates of contaminated allopurinol tablets and ready-to-eat food, of which some were identical to patients' isolates, and with one isolate in the cornstarch used as an excipient for manufacture of this drug. We attempted to type the isolates by random amplification of polymorphic DNA analysis, with limited evidence of clonal distribution. The primary source of the contaminating fungus was likely to be the cornstarch used in the manufacturing of allopurinol tablets or ready-to-eat food. Rhizopus microsporus is thermotolerant and can multiply even at 50°C. The long holding time of the intermediates during the manufacturing process of allopurinol amplified the fungal load. Microbiological monitoring of drugs manufactured for highly immunosuppressed patients should be considered.Zygomycosis has become an important emerging infection in patients with hematological malignancy undergoing chemotherapy or bone marrow transplantation (24), especially with the availability of voriconazole as antifungal prophylaxis (25,28,44). Breakthrough zygomycosis in patients on voriconazole prophylactic treatment is usually manifested as sinopulmonary or rhinocerebral disease, since the fungal spores are ubiquitously found in the environment and could therefore be acquired through inhalation or traumatic inoculation through the skin or mucosa. Gastrointestinal zygomycosis has been a rare clinical entity (50, 54), but cases or outbreaks of tongue, gastric, or cutaneous zygomycosis due to Rhizopus microsporus after exposure to contaminated wooden tongue depressors have been reported (23,26,33).The Rhizopus microsporus species gr...

BackgroundPositive 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 FindingsClinical 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.ConclusionPresence 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.

In addition to age, several clinical parameters were different between pandemic A (H1N1) and seasonal influenza. However, since both seasonal and pandemic influenza can lead to significant morbidity and mortality, the impact of pre-existing seasonal influenza should not be underestimated during the pandemic period.

h 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 chromatographyelectrospray 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 4␣-formyl-4␤-methyl-5␣-cholesta-8-en-3␤-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 ( T uberculosis (TB) is a disease caused by the bacterium Mycobacterium tuberculosis. Although it is a well-known disease that has been around for much of human history, there are still millions of new TB cases occurring per year worldwide, and TB remains a leading cause of deaths worldwide, especially in developing countries. Since the 1980s, TB has reemerged as a result of the AIDS epidemic and increasing use of immunosuppressants. In recent years, a higher incidence of extrapulmonary disease in immunocompromised hosts and the emergence of multidrug-resistant strains have further complicated diagnosis and treatment (1-3). Despite the medical importance of TB, diagnosis is still associated with many unresolved problems. The traditional gold standard methods are smear and culture for acid-fast bacilli from clinical specimens. Although culture offers higher sensitivity and specificity than those of smears, it is not useful for culture-negative cases, especially in early, disseminated, or extrapulmonary disease (4, 5). Moreover, it often takes 2 to 6 weeks before culture is positive and even longer for definitive species identification. While newer diagnostic modalities, such as adenosine deaminase levels in pleural fluid, lipoarabinomannan levels in urine, PCR, and Xpert MTB/RIF assays, have been developed (6-12), there are still limitations in terms of their sensitivity and/or specificity.Metabolomics is an emerging platform for studies of infectious diseases or pathogens (13)(14)(15)(16)(17)(18)(19). For TB, the technique has been applied on cultured isolates for differentiation from other Mycobacterium species and studies on the biology and virulence of tuberculosis (14,15,(20)(21)(22). For example, lipidomics studies have revealed novel metabolites potentially associated with growth and virulence of M. tuberculosis (23,24). We also recently identified ...

Shewanella is a rare human pathogen that can lead to fatal infections. However, clinical information about this bacterium remains scarce. In this study, we retrospectively reviewed all patients with laboratory isolates of Shewanella over an 8-y period to assess risk factors, clinical manifestations and outcome. Twenty-nine patients were identified. Shewanella was most commonly isolated from intra-abdominal specimens (48.2%), followed by skin and soft tissue specimens (27.6%), blood (13.8%) and sputum (10.3%). Malignancy, hepatobiliary disease and diabetes mellitus were common underlying diseases. The overall 30-day mortality rate was 20.6%. Shewanella was considered a definite causative pathogen in 7 patients, and a recurrent infection occurred in 2 patients. Colonization of the biliary tract was common. Among co-isolated pathogens, the enteric flora was most represented. All isolates were susceptible to ceftazidime and aminoglycosides, but 1 isolate was resistant to imipenem. In conclusion, Shewanella may become a colonizing bacterium, subsequently causing invasive diseases in patients with an underlying disease.

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.