***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: INTRODUCTION The cost-effectiveness of blood cultures in community-acquired pneumonia ( CAP ) has been question ed . Although penicillin-resistant Streptococcus pneumoniae is an increasing problem , penicillin therapy , where appropriate , reduces cost and may reduce antibiotic resistance . Blood cultures , however , can only reduce cost if physicians are prepared to alter therapy based on the results . We review ed our experience to determine how often physicians changed management based on blood culture results positive for S pneumoniae . METHODS Retrospective chart review was performed of all CAP admissions between January 1996 and December 1998 with blood culture results positive for S pneumoniae . RESULTS Seventy-four patients out of 1,805 patients admitted with CAP during this period had pneumococcemia .  Penicillin resistance was identified in 15 cases ( 20.3 % ; high grade in 4 cases ) with cephalosporin resistance in 4 of these cases ( 1 high grade ) . Fifty-one patients had initial empiric therapy with a third-generation cephalosporin , and 58 patients had empiric coverage of atypical organisms ; no patient received empiric penicillin therapy . Blood culture results altered management in 31 patients ( 41.9 % ) , but in only 2 cases was this due to antibiotic resistance . Fifty-one patients without penicillin allergy grew penicillin-sensitive pneumococci ; only 11 patients ( 21.6 % ) were changed to penicillin therapy . Thirteen of 35 patients ( 37.1 % ) who were given an additional antibiotic for atypical coverage had this antibiotic ceased . CONCLUSION Despite evidence of penicillin-sensitive pneumococcal CAP , physicians were reluctant to narrow antibiotic therapy , potentially adding to treatment cost and reducing the impact of blood culture results on management . The impact of penicillin resistance was reduced by the usual empiric choice of a third-generation cephalosporin . While positive blood culture results can clearly be useful in the management of patients with CAP , their cost-effectiveness needs to be assessed in prospect i ve clinical trials STUDY OBJECTIVE Although it is considered st and ard of care to obtain blood cultures on patients hospitalized for pneumonia , several studies have question ed the utility and cost-effectiveness of this practice . The objective of this study is to determine the impact of emergency department ( ED ) blood cultures on antimicrobial therapy for patients with pneumonia . METHODS We performed a prospect i ve , observational , cohort study of consecutive adult ( age > or = 18 years ) patients treated at an urban university ED between February 1 , 2000 and February 1 , 2001 . Inclusion criteria were radiographic evidence of pneumonia , clinical evidence of pneumonia , and blood culture obtained . Blood cultures were classified as positive , negative , or contaminant based on previously established criteria . Additionally , data were collected on antimicrobial sensitivities , empiric antibiotic therapy , antibiotic changes , and reasons for changes . RESULTS There were 3,926 ED visits with blood cultures obtained for any reason , of which 3,762 ( 96 % ) were available for review . Of these , 414 of 3,762 ( 11 % ) patients met pneumonia study inclusion criteria , and blood cultures identified 29 of 414 ( 7.0 % ) patients with true bacteremia . In the 414 patients , blood culture results altered therapy for 15 patients ( 3.6 % ) with suspected pneumonia , of which 11 ( 2.7 % ) patients had their coverage narrowed ; only 4 ( 1.0 % ) patients had their coverage broadened because of resistance to empiric therapy . For the 11 patients with bacteremia whose therapy was not altered , culture results actually supported narrowing therapy in 8 ( 1.9 % ) cases , but this was not done . CONCLUSION Blood cultures rarely altered therapy for patients presenting to the ED with pneumonia . More discriminatory blood culture use may potentially reduce re source utilization BACKGROUND Penicillin-resistant strains of Streptococcus pneumoniae are now found worldwide , and strains with resistance to cephalosporin are being reported . The appropriate antibiotic therapy for pneumococcal pneumonia due to resistant strains remains controversial . METHODS To examine the effect of resistance to penicillin and cephalosporin on mortality , we conducted a 10-year , prospect i ve study in Barcelona of 504 adults with culture-proved pneumococcal pneumonia . RESULTS Among the 504 patients , 145 ( 29 percent ) had penicillin-resistant strains of S. pneumoniae ( minimal inhibitory concentration [ MIC ] of penicillin G , 0.12 to 4.0 micrograms per milliliter ) , and 31 patients ( 6 percent ) had cephalosporin-resistant strains ( MIC of ceftriaxone or cefotaxime , 1.0 to 4.0 micrograms per milliliter ) . Mortality was 38 percent in patients with penicillin-resistant strains , as compared with 24 percent in patients with penicillin-sensitive strains ( P = 0.001 ) . However , after the exclusion of patients with polymicrobial pneumonia and adjustment for other predictors of mortality , the odds ratio for mortality in patients with penicillin-resistant strains was 1.0 ( 95 percent confidence interval , 0.5 to 1.9 ; P = 0.84 ) . Among patients treated with penicillin G or ampicillin , the mortality was 25 percent in the 24 with penicillin-resistant strains and 19 percent in the 126 with penicillin-sensitive strains ( P = 0.51 ) . Among patients treated with ceftriaxone or cefotaxime , the mortality was 22 percent in the 59 with penicillin-resistant strains and 25 percent in the 127 with penicillin-sensitive strains ( P = 0.64 ) The frequency of resistance to cephalosporin increased from 2 percent in 1984 - 1988 to 9 percent in 1989 - 1993 ( P = 0.002 ) . Mortality was 26 percent in patients with cephalosporin-resistant S. pneumoniae and 28 percent in patients with susceptible organisms ( P = 0.89 ) . Among patients treated with ceftriaxone or cefotaxime , mortality was 22 percent in the 18 with cephalosporin-resistant strains and 24 percent in the 168 with cephalosporin-sensitive organisms ( P = 0.64 ) . CONCLUSIONS Current levels of resistance to penicillin and cephalosporin by S. pneumoniae are not associated with increased mortality in patients with pneumococcal pneumonia . Hence , these antibiotics remain the therapy of choice for this disease Objectives Although blood cultures are commonly ordered in the emergency department , there is controversy about their utility . This study aim ed to determine the usefulness of blood cultures in the management of patients presenting to a tertiary adult teaching hospital emergency department in Perth , Western Australia . Methods A detailed chart review was undertaken of all blood cultures taken in our emergency department over a 2-month period . All patients within the hospital having blood cultures taken were identified ; from this group , blood cultures originating from the emergency department were review ed . Data were collected concerning patient demographics , culture indication , vital signs , culture outcome , disposition and alterations in management result ing from the blood culture . Results 218 blood cultures were ordered from the emergency department during the study period . This represented 4.0 % ( 218/5478 ) of the total number of patients seen . Of the 218 cultures , only 30 were positive ( 13 % of the study population ) , with 16 ( 7.3 % ) probable contaminants and 14 ( 6.4 % ) true positives . No anaerobic isolates were identified . Of the 14 significantly positive blood cultures , the result influenced management in six patients , result ing in a useful culture rate of 2.8 % ( 6/218 ) . Conclusion Blood cultures are ordered on a significant number of patients seen in the emergency department but rarely alter management . Our findings in conjunction with other studies suggest that eliminating blood cultures in immunocompetent patients with common illnesses such as urinary tract infection , community acquired pneumonia and cellulitis , may significantly reduce the number of blood cultures , producing substantial savings without jeopardizing patient care . This needs prospect i ve study and validation BACKGROUND Since the last British study of the microbial aetiology of community acquired pneumonia ( CAP ) about 20 years ago , new organisms have been identified ( for example , Chlamydia pneumoniae ) , new antibiotics introduced , and fresh advances made in microbiological techniques . Pathogens implicated in CAP in adults admitted to hospital in the UK using modern and traditional microbiological investigations are described . METHODS Adults aged 16 years and over admitted to a teaching hospital with CAP over a 12 month period from 4 October 1998 were prospect ively studied . Sample s of blood , sputum , and urine were collected for microbiological testing by st and ard culture techniques and new serological and urine antigen detection methods . RESULTS Of 309 patients admitted with CAP , 267 fulfilled the study criteria ; 135 ( 50.6 % ) were men and the mean ( SD ) age was 65.4 ( 19.6 ) years . Aetiological agents were identified from 199 ( 75 % ) patients ( one pathogen in 124 ( 46 % ) , two in 53 ( 20 % ) , and three or more in 22 ( 8 % ) ) : Streptococcus pneumoniae 129 ( 48 % ) , influenza A virus 50 ( 19 % ) , Chlamydia pneumoniae 35 ( 13 % ) , Haemophilus influenzae 20 ( 7 % ) , Mycoplasma pneumoniae 9 ( 3 % ) , Legionella pneumophilia 9 ( 3 % ) , other Chlamydiaspp 7 ( 2 % ) , Moraxella catarrhalis 5 ( 2 % ) , Coxiella burnetii 2 ( 0.7 % ) , others 8 ( 3 % ) . Atypical pathogens were less common in patients aged 75 years and over than in younger patients ( 16 % v27 % ; OR 0.5 , 95 % CI 0.3 to 0.9 ) . The 30 day mortality was 14.9 % . Mortality risk could be stratified by the presence of four “ core ” adverse features . Three of 60 patients ( 5 % ) infected with an atypical pathogen died . CONCLUSION S pneumoniae remains the most important pathogen to cover by initial antibiotic therapy in adults of all ages admitted to hospital with CAP . Atypical pathogens are more common in younger patients . They should also be covered in all patients with severe pneumonia and younger patients with non-severe infection BACKGROUND Prompt antibiotic administration , oxygenation measurement , and blood cultures are generally considered markers of high- quality care in the inpatient management of community-acquired pneumonia ( CAP ) . However , few studies have examined the relationship between prompt achievement of process-of-care markers and outcomes for patients with CAP . We examined whether antibiotic administration within 8 hours of hospital arrival , a blood culture within 24 hours , an oxygenation measurement within 24 hours , or performing blood cultures before giving antibiotics was associated with the following : ( 1 ) reaching clinical stability within 48 hours of hospital admission , ( 2 ) a decreased length of hospital stay , or ( 3 ) fewer inpatient deaths . METHODS A retrospective medical record review identified 1062 eligible patients discharged from the hospital with a diagnosis of CAP between December 1 , 1997 , and February 28 , 1998 , among 38 US academic hospitals . We assessed the independent relationship between each process marker and the 3 clinical outcomes , controlling for the Pneumonia Severity Index on admission . We also examined the relationship of pneumonia severity on admission to process marker achievement and clinical outcomes . RESULTS Overall , there was no consistent or statistically significant relationship between achieving process markers and better clinical outcomes ( P>.40 for all ) . We did observe that performing blood cultures within 24 hours was related to not achieving clinical stability within 48 hours ( odds ratio , 1.62 ; 95 % confidence interval , 1.13 - 2.33 ) . However , this finding likely reflects residual confounding by severity of illness , since increasing pneumonia severity on admission was associated with blood culture performance ( P = .009 ) and with shorter times to antibiotic administration ( P = .04 ) . CONCLUSIONS Achieving process-of-care markers was not associated with improved outcomes , but was related to the severity of pneumonia as assessed on admission . Our results highlight the difficulty in demonstrating a link between process-of-care markers and outcomes in observational studies of CAP . R and omized studies are needed to objective ly evaluate the impact of process-of-care markers on CAP outcomes To assess the association between inclusion of a macrolide in a beta-lactam-based empirical antibiotic regimen and mortality among patients with bacteremic pneumococcal pneumonia , 10 years of data from a data base were analyzed . The total available set of putative prognostic factors was subjected to stepwise logistic regression , with in-hospital death as the dependent variable . Of the 409 patients analyzed , 238 ( 58 % ) received a beta-lactam plus 
    Output:
    
BCs have very limited utility in immunocompetent patients hospitalized with CAP .