暂无摘要。

Pneumonia is the leading cause of mortality in pediatric population. The etiology of pneumonia in this population is variable and changes according to age and disease severity and where the study is conducted. Our aim was to determine the etiology of community-acquired pneumonia (CAP) in children aged 1 month to 17 years admitted to 13 Colombian hospitals.
Prospective cohort study. Hospitalized children with radiologically confirmed CAP and ≤ 15 days of symptoms were included and followed together with a control group. Induced sputum (IS) was submitted for stains and cultures for pyogenic bacteria and Mycobacterium tuberculosis, and multiplex PCR (mPCR) for bacteria and viruses; urinary antigens for pneumococcus and Legionella pneumophila; nasopharyngeal swabs for viruses, and paired serology for atypical bacteria and viruses. Additional cultures were taken at the discretion of primary care pediatricians.
Among 525 children with CAP, 71.6% had non-severe pneumonia; 24.8% severe and 3.6% very severe pneumonia, and no fatal cases. At least one microorganism was identified in 84% of children and 61% were of mixed etiology; 72% had at least one respiratory virus, 28% pyogenic bacteria and 21% atypical bacteria. Respiratory syncytial virus, Parainfluenza, Rhinovirus, Influenza, Mycoplasma pneumoniae, Adenovirus and Streptococcus pneumoniae were the most common etiologies of CAP. Respiratory syncytial virus was more frequent in children under 2 years and in severe pneumonia. Tuberculosis was diagnosed in 2.3% of children. IS was the most useful specimen to identify the etiology (33.6%), and blood cultures were positive in 3.6%. The concordance between all available diagnostic tests was low. A high percentage of healthy children were colonized by S. pneumoniae and Haemophilus influenzae, or were infected by Parainfluenza, Rhinovirus, Influenza and Adenovirus.
Respiratory viruses are the most frequent etiology of CAP in children and adolescents, in particular in those under 5 years. This study shows the challenges in making an etiologic diagnosis of CAP in pediatric population because of the poor concordance between tests and the high percentage of multiple microorganisms in healthy children. IS is useful for CAP diagnosis in pediatric population.

In the context of age- and risk-based pneumococcal vaccine recommendations in Canada, this study presents updated data from active surveillance of pneumococcal community acquired pneumonia (pCAP) and invasive pneumococcal disease (IPD) in hospitalized adults from 2010 to 2017.
S. pneumoniae was detected using culture (blood and sputum), and urine antigen detection (UAD). Serotyping was performed with Quellung, PCR, or using the PCV13- and PPV23 (non-PCV13)-specific UADs. Laboratory results, demographic, and outcome data were categorized by age (16-49, 50-64, and 65 + ) and by disease [non-bacteremic pCAP, bacteremic pCAP, and IPD(non-CAP)].
11,129 CAP cases and 216 cases of IPD (non-CAP) were identified. Laboratory testing for S. pneumoniae was performed in 8912 CAP cases, identifying 1264 (14.2%) as pCAP. Of pCAP cases, 811 (64.1%) were non-bacteremic and 455 (35.9%) were bacteremic. Adults 65 + years represented 54.5% of non-bacteremic pCAP, 41.4% of bacteremic pCAP, and 48.6% of IPD cases. Adults 50-64 years contributed 30.3%, 33.1%, and 29.9%, respectively. In pCAP, PCV13 serotypes declined between 2010 and 2014 due to declines in serotypes 7F and 19A, then plateaued from 2015 to 2017 with persistence of serotype 3. In later study years, non-bacteremic pCAP was predominant, and PPV23 (non-PCV13) serotypes increased from 2015 to 2017, with serotypes 22F, 11A, and 9 N being most frequently identified. Compared to non-pCAP, pCAP cases were more likely to be admitted to intensive care units and require mechanical ventilation. These outcomes and mortality were more common in bacteremic pCAP and IPD, versus non-bacteremic pCAP.
Along with IPD, pCAP surveillance (bacteremic and non-bacteremic) is important as their trends may differ over time. With insufficient herd protection from PCV13 childhood immunization, or use of PPV23 in adults, this study supports direct adult immunization with PCV13 or higher valency conjugate vaccines to reduce the residual burden of pCAP and IPD.

Background: Blastomycosis can cause severe disease with progressive respiratory failure and dissemination even in immunocompetent individuals. We sought to evaluate risk factors for severe disease and mortality using clinical and laboratory data within a large health system in an endemic area. Methods: We performed a retrospective cohort study of patients diagnosed with blastomycosis at all Mayo Clinic sites from 1 January 2004 through 31 March 2020. Diagnosis was established by culture, histopathology/cytopathology, serology, antigen testing, or PCR. Disease was categorized as mild for patients treated in the outpatient setting, moderate for hospitalized patients who did not require intensive care, and severe for patients admitted to the intensive care unit. Logistic regression was used to evaluate risk factors for severe disease. A Cox proportional hazards model was constructed to evaluate mortality. Findings: We identified 210 patients diagnosed with blastomycosis. Mean age was 51 years (range, 6-84). Most subjects were male (71.0%). Extrapulmonary disease was confirmed in 24.8%. In this cohort, 40.5% of patients had mild disease, 37.6% had moderate disease, and 21.9% had severe disease. Independent risk factors for severe disease were neutrophilia (odds ratio (OR) 3.35 (95% CI 1.53-7.35), p = 0.002) and lymphopenia (OR 3.34 (95% CI 1.59-7.03), p = 0.001). Mortality at 90 days was 11.9%. Median time from diagnosis to death was 23 days (interquartile range 8-31 days). Independent risk factors for mortality were age (OR 1.04 (95% CI 1.01-1.08), p = 0.009), neutrophilia (OR 2.84 (95% CI 1.04-7.76), p = 0.041), and lymphopenia (OR 4.50 (95% CI 1.67-12.11), p = 0.003). Blastomyces immunodiffusion had an overall sensitivity of 39.6% (95% CI 30.1-49.8). Sensitivity was higher among those who were tested 4 weeks or longer after the onset of symptoms. Urine Blastomyces antigen had a significantly higher sensitivity of 80.8% (95% CI 68.1-89.2) compared to serology. There was a trend towards higher antigen concentration in patients with severe disease. The sensitivity of PCR from respiratory specimens was 67.6% (95% CI 50.1-85.5). Conclusion: In this cohort, we did not find an association between pharmacologic immunosuppression and disease severity. Lymphopenia at diagnosis was an independent risk factor for mortality. This simple marker may aid clinicians in determining disease prognosis.

Disseminated histoplasmosis (DH) is endemic in Latin America and the Caribbean where diagnostic tools are restricted. We carried-out a 1-year prospective cohort study at a referral hospital in São Paulo, Brazil. Participants had > or =18 years old, were hospitalized due to any indication and had CD4+ < 200 cells/µl. A urine commercial monoclonal Histoplasma galactomannan enzyme-linked immunosorbent assay (IMMY, Norman, OK, USA) and \'in house\' Histoplasma blood nested PCR were performed in all cases. Probable/proven DH cases were defined according to international guidelines. Conventional mycological methods were available in routine conditions to investigate suspected DH cases. Treatment of participants followed the institutional routine. One-hundred six participants were included. Median age (interquartile range [IQR]) was 39.5 years (30.0-47.3) and 80 individuals (75.5%) were males. Median (IQR) CD4 cell count was 26.5 (9.4-89.3) cells/mm3. DH was diagnosed in 8/106 patients (7.5%). Antigen assay and/or PCR were positive in 4.7% (5/106) of patients. The antigen assay and/or PCR identified 37.5% (3/8) of DH cases, which had not been diagnosed with conventional mycological methods, but had clinical manifestations compatible with HD. In conclusion, the use of Histoplasma urine antigen and Histoplasma blood PCR guided by CD4 status contributed to the diagnosis of DH in hospitalized individuals. These assays were complementary to conventional mycologic methods and are urgently needed in our setting.
UNASSIGNED: In this prospective cohort study carried-out in a referral center in São Paulo, Brazil, we found a high frequency of AIDS-related disseminated histoplasmosis (8/106, 7.5%). We used urine antigen test and blood PCR assay to improve the diagnosis of this opportunistic disease.

Acute disseminated histoplasmosis (ADH) is an AIDS-defining illness and reported in Cameroon, but there are few data about its incidence. Between June and August 2019, we conducted a descriptive cross-sectional study to screen for histoplasmosis in a population of adults with HIV infection, irrespective of their CD4 T-cell counts, using Histoplasma urine antigen detection enzyme immunoassay (EIA) and histoplasmin skin test. Of the 138 participants screened, 36 (26%) had detectable antigen in urine, using an OD cut off of 0.045. Skin lesions were present in two (6%) cases. Of 39 patients tested for histoplasmin skin test positivity, one was positive. Histoplasma antigenuria was associated with a positive history of chest infection (Odds ratio: 3.632, 95% confidence interval: 1.635-8.071, p= 0.001). As 30 (21.7%) of titres were between 0.045 (the current cut off) and 0.25, the cut off may need adjustment in Cameroon, using disease confirmation with alternative, highly sensitive diagnostic approaches such as PCR and bone marrow examination. H. capsulatum infection appears to be common among HIV-infected patients attending outpatient clinics at the Buea Regional Hospital. There is an acute need to improve awareness and management of HIV patients with respect to H. capsulatum infection.

Blastomycosis is endemic in Wisconsin with Blastomyces dermatitidis and B. gilchristii responsible for infections. Urine antigen testing is a non-invasive diagnostic method for blastomycosis with up to 93% test sensitivity. However, the test\'s sensitivity has not been evaluated with relationship to B. gilchristii infections.
We aimed to assess physician use of the urine antigen assay and its sensitivity to B. gilchristii and B. dermatitidis infections in a retrospective study. Culture confirmed clinical cases of blastomycosis from 2008-2016 were identified within Marshfield Clinic Health System (MCHS) and UW Hospital and Clinics (UWHC) medical records. Clinical data were abstracted from each medical record and included the following: patient demographics, presence of immune compromising and underlying medical conditions, treatment drugs, presence of isolated pulmonary or disseminated disease, death, urine antigen testing, timeframe of testing, and quantitative test values (EIA units or ng/mL).
A total of 140 blastomycosis cases were included in this study, with MCHS contributing 114 cases to the study and UWHC contributing 26 cases. The majority of UWHC cases (n=22; 85%) were caused by B. dermatitidis and the majority of MCHS cases (n=73; 64%) were caused by B. gilchristii. UWHC physicians were significantly more likely to treat with multiple drugs during the course of infection and were more likely to prescribe amphotericin B and voriconazole. Urine antigen testing was more frequently used at UWHC (n=24; 92%) than MCHS (n=51; 45%; P < 0.00001). In this study, the urine antigen assay demonstrated 79% sensitivity. Sensitivity was significantly associated with the timeframe of testing (P < 0.05), with most true positive urine antigen tests (83%) being performed ≤ 7 days from diagnosis. In this study, the urine antigen assay was capable of detecting both B. dermatitidis and B. gilchristii at about equal sensitivity. Urine antigen concentration (ng/mL) trended higher in B. dermatitidis infections.
This study found that the urine antigen assay is capable of detecting both species of Blastomyces at about the same sensitivity. We recommend continued use of the urine antigen assay for diagnosis of blastomycosis and recommend that the assay be used early in the diagnostic process to minimize the chance of false negative results.

Histoplasma capsulatum, a dimorphic fungus found world-wide, is endemic to regions of the Mississippi and Ohio River valleys and portions of Central and South America. Initial infection can present with acute pulmonary symptoms or remain clinically asymptomatic, with disease course generally guided by degree of inoculum and underlying immunosuppression. A chronic, progressive course of weight loss, oral ulceration, and fatigue has been associated with elderly males. We present a 79-year-old man with a chronic, progressive course of oral lesions, odynophagia, and weight loss who was found to have histoplasmosis on oral biopsy performed for suspicions of oropharyngeal squamous cell carcinoma. Histoplasma urine antigen, serum complement fixation antibody titers, and fungal tissues were all negative despite validated sensitivities in the >90% range. Our case report highlights the critical role of tissue biopsy in establishing a diagnosis of oropharyngeal histoplasmosis.

BACKGROUND: An outbreak of Streptococcus pneumoniae (pneumococcal) infection complicated by concomitant influenza A on an elderly care ward was detected.
METHODS: Thirteen patients with hospital-acquired respiratory infections were investigated during the course of the outbreak investigation. Six had a positive BinaxNOW S. pneumoniae urinary antigen test and two patients had culture-confirmed pneumococcal bacteraemia and a positive urine antigen test. Five patients gave positive influenza A PCR results of which two were also positive for S. pneumoniae antigen.
CONCLUSIONS: The concurrence of influenza and pneumococcal infections made tracking the course of the infection difficult. This case study shows how the use of a sensitive, S. pneumoniae serotype-specific urine antigen assay, in the absence of cultured isolates, helped determine whether patients were infected with the same pneumococcal serotype. This was particularly useful when additional respiratory symptoms were seen following the administration of chemoprophylaxis.

Legionella is a Gram-negative bacterium that can cause Pontiac fever, a mild upper respiratory infection and Legionnaire\'s disease, a more severe illness. We aimed to compare the performance of urine antigen, culture, and polymerase chain reaction (PCR) test methods and to determine if sputum is an acceptable alternative to the use of more invasive bronchoalveolar lavage (BAL). Data for this study included specimens tested for Legionella at Public Health Ontario Laboratories from 1st January, 2010 to 30th April, 2014, as part of routine clinical testing. We found sensitivity of urinary antigen test (UAT) compared to culture to be 87%, specificity 94.7%, positive predictive value (PPV) 63.8%, and negative predictive value (NPV) 98.5%. Sensitivity of UAT compared to PCR was 74.7%, specificity 98.3%, PPV 77.7%, and NPV 98.1%. Out of 146 patients who had a Legionella-positive result by PCR, only 66 (45.2%) also had a positive result by culture. Sensitivity for culture was the same using either sputum or BAL (13.6%); sensitivity for PCR was 10.3% for sputum and 12.8% for BAL. Both sputum and BAL yield similar results regardless testing methods (Fisher Exact p-values = 1.0, for each test). In summary, all test methods have inherent weaknesses in identifying Legionella; therefore, more than one testing method should be used. Obtaining a single specimen type from patients with pneumonia limits the ability to diagnose Legionella, particularly when urine is the specimen type submitted. Given ease of collection and similar sensitivity to BAL, clinicians are encouraged to submit sputum in addition to urine when BAL submission is not practical from patients being tested for Legionella.