Diagnosis Of Lower Respiratory Tract Infections Research Articles

Stacked Ensemble Improvement of the Lower Respiratory Tract Infection Diagnoses in Peadiatric

Lower Respiratory Tract Infections (LRTIs) are the second and third causes of pediatric patients' death in Nigeria and the United States of America. It is observed from several reviewed literature that the LRTIs accounted for more than a million children morbidity and mortality yearly due to lack of prompt diagnosis or no diagnosis due to a shortage of medical experts and medical facilities in our localities. Intense research is ongoing on applying machine learning (ML) to its clinical diagnosis and reducing its spread in pediatric patients. In this research, K-Nearest Neighbor (KNN), C4.5 Decision Tree, and Naive Bayes' ML algorithms were used to develop three base diagnosis models with Correlation, consistency, and information gain selected feature of the LRTI dataset, Multiple Model Trees (MMT) Meta algorithm is used to combine and improve the diagnoses of all the base models using stacked ensemble. The preliminary diagnosis findings using base models have established that the information gained feature extraction method performed much better than the other two. It, therefore, suffix that the results from this should be used for further processing. All the models built with the reduced feature set recorded improved diagnoses accuracy more than the model built with the whole feature set. The MMT stacked ensemble models recorded an improvement on the diagnosis of LRTIs in Peadiatric, it recorded the highest diagnostic accuracies improvement of 12.80%, 13.52%, and 12.37%, and lowest diagnostic accuracies improvement of 6.37%, 5.22%, and 6.09% with the MMT stacked ensemble models of the Consistency, the Correlation, and the information gain reduced selected feature set respectively. These experimental results show the potential for this approach to deliver a reliable and improved diagnosis of LRTIs. It is recommended to be used to diagnose LRTIs in primary health care centers to reduce its mortality rate.

Particulate matter at third trimester and respiratory infection in infants, modified by GSTM1.

To investigate the association between particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5 ) exposure during each trimester of pregnancy and development of lower respiratory tract infections (LRTIs) during the first 3 years of life and whether GSTM1 gene polymorphisms modify these effects. This study included 1,180 mother-child pairs from the Cohort for Childhood Origin of Asthma and allergic diseases. The PM2.5 levels during pregnancy were estimated by residential address using land-use regression models based on a national monitoring system. A diagnosis of LRTIs was based on a parental report of a physician's diagnosis. Real-time polymerase chain reaction was used for GSTM1 genotyping. Higher PM2.5 exposure during the third trimester was associated with LRTIs at 1 year of age (aRR, 1.06; 95% CI, 1.00-1.13). This result did not change after adjusting for PM2.5 exposures during the first and second trimesters (aRR, 1.06; 95% CI, 0.99-1.13). This association was significant after adjusting for PM2.5 exposures during first year of age (aRR, 1.08; 95% CI, 1.02-1.15) and exposures to NO2 and ozone at the third trimester (aRR, 1.07; 95% CI, 1.00-1.16). In addition, PM2.5 exposure during the third trimester increased the risk of LRTIs at 1 year of age in cases with the GSTM1 null genotype (aRR, 1.26; 95% CI, 1.01-1.57; P for interaction .20). Higher PM2.5 exposure during the third trimester of pregnancy may increase the susceptibility to LRTIs at 1 year of age. This effect is modified by GSTM1 gene polymorphisms.

Diagnostic value of serum neutrophil gelatinase-associated lipocalin, interleukin-6 and anti-citrullinated alpha-enolase peptide 1 for lower respiratory tract infections

ObjectivesThe aim of this study was to explore the auxiliary diagnostic value of neutrophil gelatinase-associated lipocalin (NGAL) and anti-citrullinated alpha-enolase peptide 1 (CEP-1) in lower respiratory tract infections (LRTIs). MethodsBlood samples were collected from 99 in-patients with LRTIs [62 community-acquired pneumonia (CAP), 14 acute exacerbated chronic obstructive pulmonary diseases (AECOPD), 23 other diseases] and 50 healthy subjects. NGAL, CEP-1 and IL-6 were measured and compared. IL-6 was tested by electrochemiluminescence assay kit on Roche E601 immunology analyzer, CEP-1 was assessed with enzyme-linked immunosorbent assay kit, and NGAL was detected by latex immunoturbidimetric assay kit on Beckman Coulter AU2700. ResultsCompared with healthy controls, NGAL and IL-6 levels were significantly increased in the patients with LRTIs, the area under the curves (AUC) was 0.97 and 0.88 respectively (P < 0.01). The sensitivity and specificity of NGAL at a cut-off of 86 ng/ml were 93.0% and 96.0%, respectively, in which the sensitivity was consistent with IL-6 (P = 0.21) and the specificity was better than IL-6 (P < 0.01). CEP-1 slightly increases in the patient group, however the difference was not significant (P = 0.41). The levels of NGAL and IL-6 was no differences in different diseases, the P-value was 0.50 and 0.29, respectively. LRTIs with and without underlying diseases have similar NGAL and IL-6 values. ConclusionsNGAL, rather than CEP-1, may be appealing adjuncts for diagnosis of LRTIs. NGAL proved to be a better biomarker than IL-6.

The Etiology of Viral Lower Respiratory Tract Infections at a Tertiary Hospital in Jordan over Five Years

Background&#x0D; Lower respiratory tract infection (LRTI) is the most common condition treated in primary care and is considered the third leading cause of death worldwide. The objective of our study is to determine the etiological agents that cause viral LRTI in Jordan, aiming to help physicians to choose the appropriate treatment strategy.&#x0D; Materials and Methods &#x0D; We conducted a retrospective study on patients who were admitted with the diagnosis of LRTI between January, 2011 and January, 2016. We used Fast-track Diagnostics (FTD)® Respiratory 21 Kit (Fast-track Diagnostics, Luxembourg) real-time PCR to determine the viral etiology of LRTI, and we investigated pandemic H1N1 2009 swine flu virus using rapid test PCR.&#x0D; Results &#x0D; This study involved 495 patients with a mean age of 57.79 ± 18.43 years. The causative agents were identified in 157 patients out of 495 patients (31.7%). FTD real-time PCR was done for 170 patients, and the test was positive for seasonal Influenza A virus in 7.1% of patients, influenza B in 4.1%, RSV in 4.7%, metapneumovirus in 4.1%, adenovirus in 4.1%, corona 229E/NL63 in 4.1%, parainfluenza virus in 7.6%, and rhinovirus in 3.5%. The percent of cases who were positive for pandemic H1N1 2009 swine flu virus was 4.2%. The rate of ICU admission was 16.8%, and the mortality rate of LRTI was as low as 3.64%.&#x0D; Conclusions&#x0D; Viral LRTI is more common in winter season in Jordan, especially in January. Remarkably, Influenza A and Parainfluenza viruses were the main viral causative agents for LRTI in our study.

Bacterial Aetiologies of Lower Respiratory Tract Infections among Adults in Yaoundé, Cameroon.

Lower respiratory tract infections (LRTIs) remain a challenge in African healthcare settings and only few data are available on their aetiology in Cameroon. The purpose of this study was to access the bacterial cause of LRTIs in patients in Cameroon by two methods. Methods. Participants with LRTIs were enrolled in the referral centre for respiratory diseases in Yaoundé city and its surroundings. To detect bacteria, specimens were tested by conventional bacterial culture and a commercial reverse-transcriptase real-time polymerase chain reaction (RT-PCR) assay. One hundred forty-one adult patients with LRTIs were enrolled in the study. Among the participants, 46.8% were positive for at least one bacterium. Streptococcus pneumoniae and Haemophilus influenzae were the most detected bacteria with 14.2% (20/141) followed by Klebsiella pneumoniae, 9.2% (13/141), Staphylococcus aureus, 7.1% (10/141), and Moraxella catarrhalis, 4.3% (6/141). Bacterial coinfection accounted for 23% (14/61) with Haemophilus influenzae being implicated in 19.7% (12/61). The diagnostic performance of RT-PCR for bacteria detection (43.3%) was significantly different from that of culture (17.7%) (p< 0.001). Only Streptococcus pneumoniae detection was associated with empyema by RT-PCR (p<0.001). These findings enhance understanding of bacterial aetiologies in order to improve respiratory infection management and treatment. It also highlights the need to implement molecular tools as part of the diagnosis of LRTIs.

Feeding patterns of infants admitted with lower respiratory tract infections in an HIV-endemic area

Background. Lower respiratory tract infections (LRTIs) remain a major cause of mortality and morbidity in infants in South Africa (SA). Exclusive breastfeeding has been shown to decrease mortality and morbidity in infants with LRTIs, especially in the context of HIV/AIDS. Major effort has been put into educating HIV-positive mothers on the benefits of exclusive breastfeeding within effective prevention of mother-to-child transmission (PMTCT) programmes. Objectives. To determine the feeding practices among infants admitted with LRTIs in an HIV-endemic area. Methodology. The study was a retrospective chart review of all infants admitted with a diagnosis of LRTI between 1 January 2015 and 31 December 2015 at King Edward VIII Hospital, Durban, SA. Data on feeding patterns, socioeconomic status, maternal HIV status and clinical outcomes of LRTI admissions were collected. Results. Of the 308 infants enrolled, 63% were male. Exclusive breastfeeding rates of those aged <6 months with LRTIs were higher than those found in previous studies; however, these feeding patterns were significantly associated with the HIV status of the mother ( p =0.003). Mothers who were HIV-negative were twice as likely to breastfeed as those who were HIV-positive (odds ratio 2.25; 95% confidence interval 1.32- 3.88). There was no association between the type of feeding and the clinical outcomes for LRTIs. Conclusion. Maternal HIV status influenced the feeding patterns of infants admitted with LRTIs with lower exclusive breastfeeding rates in the HIV-exposed group. Despite extensive efforts to promote breastfeeding within effective PMTCT programmes, HIV-positive mothers are still not harnessing the benefits that exclusive breastfeeding provides.

Integrating host response and unbiased microbe detection for lower respiratory tract infection diagnosis in critically ill adults

Lower respiratory tract infections (LRTIs) lead to more deaths each year than any other infectious disease category. Despite this, etiologic LRTI pathogens are infrequently identified due to limitations of existing microbiologic tests. In critically ill patients, noninfectious inflammatory syndromes resembling LRTIs further complicate diagnosis. To address the need for improved LRTI diagnostics, we performed metagenomic next-generation sequencing (mNGS) on tracheal aspirates from 92 adults with acute respiratory failure and simultaneously assessed pathogens, the airway microbiome, and the host transcriptome. To differentiate pathogens from respiratory commensals, we developed a rules-based model (RBM) and logistic regression model (LRM) in a derivation cohort of 20 patients with LRTIs or noninfectious acute respiratory illnesses. When tested in an independent validation cohort of 24 patients, both models achieved accuracies of 95.5%. We next developed pathogen, microbiome diversity, and host gene expression metrics to identify LRTI-positive patients and differentiate them from critically ill controls with noninfectious acute respiratory illnesses. When tested in the validation cohort, the pathogen metric performed with an area under the receiver-operating curve (AUC) of 0.96 (95% CI, 0.86-1.00), the diversity metric with an AUC of 0.80 (95% CI, 0.63-0.98), and the host transcriptional classifier with an AUC of 0.88 (95% CI, 0.75-1.00). Combining these achieved a negative predictive value of 100%. This study suggests that a single streamlined protocol offering an integrated genomic portrait of pathogen, microbiome, and host transcriptome may hold promise as a tool for LRTI diagnosis.

Progression of the Radiologic Severity Index predicts mortality in patients with parainfluenza virus-associated lower respiratory infections.

BackgroundRadiologic severity may predict adverse outcomes after lower respiratory tract infection (LRI). However, few studies have quantified radiologic severity of LRIs. We sought to evaluate whether a semi-quantitative scoring tool, the Radiologic Severity Index (RSI), predicted mortality after parainfluenza virus (PIV)-associated LRI.MethodsWe conducted a retrospective review of consecutively-enrolled adult patients with hematologic malignancy or hematopoietic stem cell transplantation and with PIV detected in nasal wash who subsequently developed radiologically-confirmed LRI. We measured RSI (range 0–72) in each chest radiograph during the first 30 days after LRI diagnosis. We used extended Cox proportional hazards models to identify factors associated with mortality after onset of LRI with all-cause mortality as our failure event.ResultsAfter adjustment for patient characteristics, each 1-point increase in RSI was associated with an increased hazard of death (HR 1.13, 95% confidence interval [CI] 1.05–1.21, p = 0.0008). Baseline RSI was not predictive of death, but both peak RSI and the change from baseline to peak RSI (delta-RSI) predicted mortality (odds ratio for mortality, peak: 1.11 [95%CI 1.04–1.18], delta-RSI: 1.14 [95%CI 1.06–1.22]). A delta-RSI of ≥19.5 was 89% sensitive and 91% specific in predicting 30-day mortality.ConclusionsWe conclude that the RSI offers precise, informative and reliable assessments of LRI severity. Progression of RSI predicts 30-day mortality after LRI, but baseline RSI does not. Our results were derived from a cohort of patients with PIV-associated LRI, but can be applied in validated in other populations of patients with LRI.

Vitamin D Levels in Premature Children Admitted to the Hospital with Viral Respiratory Infection.

Children born preterm are at risk of hospital admission for respiratory infection in the first years of life. Vitamin D deficiency has been associated with increased risk of developing lower respiratory tract infection (LRTI). We assessed vitamin D levels in children born preterm admitted to the hospital ward or pediatric intensive care unit (PICU) with viral LRTI. A prospective observational cohort study was conducted over 3 years that enrolled 87 children <3 years of age, born <37 weeks of gestation. Children were enrolled in the ward and PICU if they had a diagnosis of LRTI with confirmed viral testing. Children seen in the outpatient clinic for well-child care were enrolled as study controls. Vitamin D and cathelicidin levels were measured and associations between vitamin D, cathelicidin, and admission sites were tested. Vitamin D levels were lower in children admitted to the PICU when compared to controls (28 ng/mL versus 36 ng/mL; P < 0.03) but were not different between children admitted to the ward or PICU. Overall, vitamin D levels were lower in children born late preterm (≥34 weeks, LPT) when compared to those born early preterm (<34 weeks, EPT), (28 ng/mL versus 34 ng/mL; P = 0.016), and EPT children were more likely to receive multivitamin supplementation before admission. Vitamin D levels in children born prematurely, admitted to the PICU, were lower than in controls. Overall levels were lower in LPT infants and this group did not receive multivitamin supplementation as much as those considered EPT. Prior research has shown associations between low vitamin D levels and respiratory disease. To our knowledge, this is the first study showing an association between low vitamin D levels and severity of respiratory disease, specifically in preterm children. Further, we found that late preterm children have lower levels of vitamin D and less frequent multivitamin supplementation.

Hospitalisation for lower respiratory tract infection in children in the province of Quebec, Canada, before and during the pneumococcal conjugate vaccine era

Streptococcus pneumoniae is an important cause of community-acquired pneumonia and pneumococcal conjugate vaccines (PCVs) may reduce this burden. This study's goal was to analyse trends in lower respiratory tract infections (LRTI) hospitalisations before and during a routine vaccination programme targeting all newborns with PCV was started in the province of Quebec, Canada in December 2004. The study population included hospital admissions with a main diagnosis of LRTI among 6-59 month-old Quebec residents from April 2000 to December 2014. Trends in proportions and rates were analysed using Cochran-Armitage tests and Poisson regression models. We observed a general downward trend in all LTRI hospitalisations rate: from 11·55/1000 person-years in 2000-2001 to 9·59/1000 in 2013-2014, a 17·0% reduction, which started before the introduction of PCV vaccination. Downward trends in hospitalisation rates were more pronounced for all-cause of pneumonia (minus 17·8%) than for bronchiolitis (minus 15·4%). There was also a decrease in the mean duration of hospital stay. There was little evidence that all-cause pneumonia decreased over the study period due mainly to the introduction of PCVs. Trends may be related to changes in clinical practice. This study casts doubt on the interpretation of ecological analyses of the implementation of PCV vaccination programmes.

Isolation and Identification of Bacteria Associated with Lower Respiratory Tract Infection among Patients Attending General Hospital Katsina

Lower respiratory tract infections (LRTIs) have been one of the major causes of morbidity and mortality worldwide. Routine diagnosis of LRTIs in our hospitals does not include adequate and extensive identification of these organisms. This study was carried out to isolate and identify some of the bacteria associated with LRTIs and their common antibiotic sensitivity pattern. Streptococcus pneumoniae was screened by Optochin disc sensitivity testing in all the samples collected. A total of 35 (41.18%) bacterial pathogens were isolated from the 85 samples collected from General Hospital Katsina. Klebsiella pneumoniae (34.29%) has the highest percentage of occurrence, followed by Staphylococcus aureus (31.43%), Pseudomonas aeruginosa (25.71%) and Escherichia coli (8.57%). Streptococcus pneumoniae was not isolated in this study. Patients in age groups 21 – 30 years and 31 – 40 years had the highest percentage of occurrence. Gentamycin and fluoroquinolones showed higher activity on the bacterial isolates and are therefore essential in the treatment of LRTIs.&#x0D;

C-reactive protein and radiographic findings of lower respiratory tract infection in infants.

AIMTo evaluate the association between C-reactive protein (CRP) and radiological evidence of lower respiratory tract infection (LRTI) in infants.METHODSAll patients aged less than 4 years who presented with suspected lower respiratory tract infection, who received a peri-presentation chest radiograph and CRP blood measurement over an 18-mo period were included in the study. Age, gender, source of referral, CRP, white cell count, neutrophil count along with the patients’ symptoms and radiologist’s report were recorded.RESULTSThree hundred and eleven patients met the inclusion criteria. Abnormal chest radiographs were more common in patients with elevated CRP levels (P < 0.01). Radiologic signs of LRTI were identified in 73.7% of chest radiographs when a patient had a CRP level between 50-99 mg/L. CRP levels were a better predictor of positive chest radiograph findings for those aged greater than I year compared to those 1 year or less.CONCLUSIONCRP may be used in patients with suspected LRTI diagnosis to select those who are likely to have positive findings on chest radiograph, thus reducing unnecessary chest radiographs.

Composition and dynamics of the respiratory tract microbiome in intubated patients.

BackgroundLower respiratory tract infection (LRTI) is a major contributor to respiratory failure requiring intubation and mechanical ventilation. LRTI also occurs during mechanical ventilation, increasing the morbidity and mortality of intubated patients. We sought to understand the dynamics of respiratory tract microbiota following intubation and the relationship between microbial community structure and infection.ResultsWe enrolled a cohort of 15 subjects with respiratory failure requiring intubation and mechanical ventilation from the medical intensive care unit at an academic medical center. Oropharyngeal (OP) and deep endotracheal (ET) secretions were sampled within 24 h of intubation and every 48–72 h thereafter. Bacterial community profiling was carried out by purifying DNA, PCR amplification of 16S ribosomal RNA (rRNA) gene sequences, deep sequencing, and bioinformatic community analysis. We compared enrolled subjects to a cohort of healthy subjects who had lower respiratory tract sampling by bronchoscopy. In contrast to the diverse upper respiratory tract and lower respiratory tract microbiota found in healthy controls, critically ill subjects had lower initial diversity at both sites. Diversity further diminished over time on the ventilator. In several subjects, the bacterial community was dominated by a single taxon over multiple time points. The clinical diagnosis of LRTI ascertained by chart review correlated with low community diversity and dominance of a single taxon. Dominant taxa matched clinical bacterial cultures where cultures were obtained and positive. In several cases, dominant taxa included bacteria not detected by culture, including Ureaplasma parvum and Enterococcus faecalis.ConclusionsLongitudinal analysis of respiratory tract microbiota in critically ill patients provides insight into the pathogenesis and diagnosis of LRTI. 16S rRNA gene sequencing of endotracheal aspirate samples holds promise for expanded pathogen identification.Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-016-0151-8) contains supplementary material, which is available to authorized users.

Predictors of hospitalization for lower respiratory tract infection in children aged

Young age, adverse environmental conditions and infectious agents are established risk factors of lower respiratory tract infection (LRTI), whereas pneumococcal conjugate vaccines may be protective. To explore their relative role as predictors of hospitalizations under the continental climate prevailing in the province of Quebec, Canada, an ecological study was performed. Records with a main diagnosis of LRTI in children born during 2007-2010 and observed up to their second-year anniversary were extracted from the provincial hospital administrative database. Respiratory virus surveillance data and statistics on ambient air temperature were obtained. Vaccine use in different birth cohorts was derived from the Quebec City Immunization Registry. Additive and multiplicative Poisson regression models were applied to estimate attributable fractions. Age, month of birth, ambient temperature, and respiratory syncytial virus (RSV), human metapneumovirus (hMPV) and influenza-positive test proportions were significant predictors of LRTI hospitalizations. No substantial differences were observed in cohorts exposed to the 7-valent or 10-valent pneumococcal conjugate vaccines. In the additive model, the fraction of hospitalizations explained by temperature variation was 37%, whereas RSV circulation explained 28%, hMPV 4% and influenza 1%. Complex interplay between biological, environmental and social mechanisms may explain the important role of ambient air temperature in predicting LRTI hospitalization risk in young children.

Retrospective cohort study of inappropriate piperacillin-tazobactam use for lower respiratory tract and skin and soft tissue infections: Opportunities for antimicrobial stewardship

Patients with skin and skin structure infections (SSTIs) and lower respiratory tract infections (LRTIs) are frequently prescribed piperacillin-tazobactam (TZP) on hospital admission. Inappropriate broad-spectrum coverage may be associated with patient harm, excess expenditure, and escalating rates of antimicrobial resistance. Patients who received empirical TZP for a diagnosis of LRTI or SSTI from January 1-June 30, 2012, were identified retrospectively. Clinical and antimicrobial data were systematically collected from electronic hospital information systems. Using published guidelines, microbiologic results, and individual clinical responses, the appropriateness of TZP use was assessed. Drug utilization after potential standard audit of therapy on day 3 was also evaluated. We reviewed 60 patients with SSTI and 169 patients with LRTI. Inappropriate empirical TZP therapy was found in 41.7% in those with SSTI, and a further 15% had inappropriate continuation of therapy. In LRTI patients, 38.3% received inappropriate empirical TZP, and 10.3% of the treatment courses were continued inappropriately. Community-acquired pneumonia was the most frequent diagnosis where TZP was used inappropriately (96%). A day 3 audit of therapy may have saved 256days of TZP. In our institution, inappropriate empirical TZP is common for community-onset infections of mild to moderate severity. A prospective audit and feedback program may be a strategy to reduce inappropriate use of TZP as empirical therapy.

Diagnostic value of the soluble triggering receptor expressed on myeloid cells‐1 in lower respiratory tract infections: A meta‐analysis

The soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) is a promising diagnostic marker for many types of infections. A bivariate meta-analysis was performed to evaluate its diagnostic value for lower respiratory tract infections (LRTI). We searched PubMed, Cochrane Library and Web of Science (from January 1966 to August 2013) for all trials assessing diagnostic value of sTREM-1 for LRTI. The pooled sensitivity, specificity, positive likelihood ratio(PLR), negative likelihood ratio(NLR), diagnostic odds ratio (DOR), the area under summary receiver operator characteristic (SROC) curve and the Q* were calculated. Thirteen studies with 1138 patients were included in our meta-analysis. The pooled sensitivity and specificity of sTREM-1 for diagnosis of LRTI was 0.84 and 0.77. The PLR, NLR and DOR were 3.6, 0.21 and 17. The area under SROC curve was 0.88 and the Q* was 0.82. The univariate meta-regression analysis demonstrated that the assay method for sTREM-1 significantly affected sensitivity for LRTI. The Q* of sTREM-1 for diagnosis of community-acquired LRTI was 0.82, and the area under SROC curve was 0.88. The Q* of sTREM-1 in diagnosis of hospital-acquired LRTI was 0.83, and the area under SROC curve was 0.90. The Q* of sTREM-1 for distinguishing culture-positive LRTI from culture-negative diseases was 0.79, and the area under SROC curve was 0.86. Current evidence suggests that sTREM-1 is an accurate marker of LRTI. The overall diagnostic value of sTREM-1 for LRTI, community-acquired LRTI and hospital-acquired LRTI is similar.

Characterization of Hospitalized Community-Onset Staphylococcus aureus Lower Respiratory Tract Infections Among Generally Healthy Persons 50 Years of Age or Younger

Background Case series have described severe lower respiratory tract infection (LRI) in healthy, community-dwelling persons caused by methicillin-resistant Staphylococcus aureus (MRSA). Evaluating populations at risk is needed. Methods Surveillance for patients aged 50 years or younger hospitalized with LRI who had S aureus isolated from blood or respiratory specimen during September 2008 to August 2010 was performed at 25 hospitals in 5 US metropolitan areas. Persons with recent health care exposure were excluded. Lower respiratory tract infection diagnosis required supporting radiographic or clinical evidence. Clinical characteristics of LRI were compared by methicillin resistance phenotype. Results In total, 94 hospitalized community-onset S aureus LRI cases were identified. Lower respiratory tract infection cases were identified in both young adults and children (60%, 35–50 years; and 19%, younger than 17 years), without any seasonality or association with influenza circulation. Among the 94 case patients with LRI, 34 patients (36%) had bacteremia, 36 patients (40%) required ICU admission, and 6 patients (6%) died; proportions were similar between cases with methicillin-susceptible S aureus and MRSA. Lower respiratory tract infection cases with MRSA had longer median length of stay compared with those with methicillin-susceptible S aureus (9 vs. 6 days; P = 0.04). Lower respiratory tract infection cases with evidence of influenza infection had higher mortality compared with LRI cases without influenza infection (31% vs. 2%; P = 0.003). During influenza circulation, 35 (55%) of 64 case patients with LRI were tested for influenza, and 9 (26%) of the 35 case patients tested positive. Conclusions S aureus LRI occurred in both adults and children, without any seasonality or association with MRSA and with and without evidence of influenza infection, although case fatality was higher among those with evidence of influenza infection.

Markers of lower respiratory tract infections in emergency departments

Background: Acute respiratory tract infections are the common causes for admission to emergency department. Appropriate diagnosis and initiating treatment on time are important for reducing morbidity and mortality rate due to lower respiratory tract infection (LRTI). The aim of this study is to determine if C-reactive protein (CRP) levels and white blood cells (WBC) count are considerable markers to help rapid diagnosis and prediction of antibiotic need for lower respiratory infections in emergency departments. The relationships between infectious agents and those markers have also been evaluated. Methods: Study subjects and control group were selected by defined criteria. Patients were analyzed and assessed for CRP and WBC, sputum Gram stain and culture besides routine laboratory tests and chest X-Rays. Results: One hundred and ninety four episodes out of 175 patients were evaluated for the study. CRP level and WBC count were detected significantly higher in patients ofstudy group than in those of control group. Pseudomonas aeruginosa and Haemophilus influenzae were the pathogens most often isolated. Conclusion: In conclusion, CRP and WBC sputum are important markers for diagnosis of LRTI at the emergency departments and results of microbiological analysis of respiratory specimens were correlated with these markers. Trial registration: Registation number of ethic committee of Dr. Suat Seren Chest Diseases and Surgery Training and Research Hospital: 28.04.2006/114

Efficacy and Safety of Procalcitonin-Guided Antibiotic Therapy in Lower Respiratory Tract Infections.

Background: In 14 randomized controlled studies to date, a procalcitonin (PCT)-based algorithm has been proven to markedly reduce the use of antibiotics along with an unimpaired high safety and low complication rates in patients with lower respiratory tract infections (LRTIs). However, compliance with the algorithm and safety out of controlled study conditions has not yet been sufficiently investigated. Methods: We performed a prospective international multicenter observational post-study surveillance of consecutive adults with community-acquired LRTI in 14 centers (Switzerland (n = 10), France (n = 3) and the United States (n = 1)). Results: Between September 2009 and November 2010, 1,759 patients were enrolled (median age 71; female sex 44.4%). 1,520 (86.4%) patients had a final diagnosis of LRTI (community-acquired pneumonia (CAP), 53.7%; acute exacerbation of chronic obstructive pulmonary disease (AECOPD), 17.1%; and acute bronchitis, 14.4%). Compliance with the PCT-guided therapy (overall 68.2%) was highest in patients with bronchitis (81.0% vs. AECOPD, 70.1%; CAP, 63.7%; p < 0.001), outpatients (86.1% vs. inpatients, 65.9%; p < 0.001) and algorithm-experienced centers (82.5% vs. algorithm-naive, 60.1%; p < 0.001) and showed significant geographical differences. The initial decision about the antibiotic therapy was based on PCT value in 72.4%. In another 8.6% of patients, antibiotics were administered despite low PCT values but according to predefined criteria. Thus, the algorithm was followed in 81.0% of patients. In a multivariable Cox hazard ratio model, longer antibiotic therapy duration was associated with algorithm-non-compliance, country, hospitalization, CAP vs. bronchitis, renal failure and algorithm-naïvety of the study center. In a multivariable logistic regression complications (death, empyema, ICU treatment, mechanical ventilation, relapse, and antibiotic-associated side effects) were significantly associated with increasing CURB65-Score, CAP vs. bronchitis, multilobar pneumonia, but not with algorithm-compliance. Discussion: Cultural and geographic differences in antibiotic prescribing affected the compliance with our PCT-guided algorithm. Efforts to reinforce compliance are needed. Antibiotic stewardship with PCT is possible, effective and safe without increasing the risk of complications in real-life conditions.

Markers of lower respiratory tract infections in emergency departments

BackgroundAcute respiratory tract infections are the common causes for admission to emergency department. Appropriate diagnosis and initiating treatment on time are important for reducing morbidity and mortality rate due to lower respiratory tract infection (LRTI). The aim of this study is to determine if C-reactive protein (CRP) levels and white blood cells (WBC) count are considerable markers to help rapid diagnosis and prediction of antibiotic need for lower respiratory infections in emergency departments. The relationships between infectious agents and those markers have also been evaluated.MethodsStudy subjects and control group were selected by defined criteria. Patients were analyzed and assessed for CRP and WBC, sputum Gram stain and culture besides routine laboratory tests and chest X-Rays.ResultsOne hundred and ninety four episodes out of 175 patients were evaluated for the study. CRP level and WBC count were detected significantly higher in patients ofstudy group than in those of control group. Pseudomonas aeruginosa and Haemophilus influenzae were the pathogens most often isolated.ConclusionIn conclusion, CRP and WBC sputum are important markers for diagnosis of LRTI at the emergency departments and results of microbiological analysis of respiratory specimens were correlated with these markers.Trial registrationRegistation number of ethic committee of Dr. Suat Seren Chest Diseases and Surgery Training and Research Hospital: 28.04.2006/114