Evaluation of housestaff physicians’ preparation and interpretation of sputum gram stains for communityacquired pneumonia

Fine, Michael J.; Orloff, John J.; Rihs, John D.; Vickers, Richard M.; Kominos, Spyros D.; Kapoor, Wishwa N.; Arena, Vincent C.; Yu, Victor L.

doi:10.1007/bf02598958

Cited by 64 publications

(26 citation statements)

References 16 publications

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“…Blood and sputum cultures are time-consuming and lack sensitivity (18,30), particularly for patients with antecedent antibiotic exposure. Sputum culture is also difficult to interpret due to oropharyngeal contamination, and sputum Gram stains are frequently unreliable (2,10,17); pleural fluid aspirates are rarely performed. Newer pneumococcal urinary antigen tests offer the promise of improved sensitivity (70 to 82%) but are reported to have variable specificity based on the standards of comparison chosen, the manner in which the test is performed and interpreted, and the particular population studied (6,8,14,20,26).…”

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confidence: 99%

Quantitative PCR Assay Using Sputum Samples for Rapid Diagnosis of Pneumococcal Pneumonia in Adult Emergency Department Patients

Yang¹,

Lin²,

Khalil³

et al. 2005

J Clin Microbiol

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Accurate diagnosis of pneumococcal pneumonia in the acute-care setting remains a challenge due to the inadequate sensitivity of conventional diagnostic tests. Sputum cultures, which are likely to have the highest diagnostic yields of all specimen types, have been considered unreliable, due to their inability to differentiate colonization from infection. Our objective was to evaluate the potential clinical utility of a rapid quantitative real-time PCR assay using sputum samples for Streptococcus pneumoniae in adult patients with communityacquired pneumonia (CAP). A prospective clinical observational study of consecutively enrolled emergency department patients with CAP was performed; only those patients with excess good-quality sputum samples were included for evaluation. Sputum samples were tested for the presence of S. pneumoniae by using a quantitative PCR that targets the pneumolysin gene. PCR findings were compared with those of a composite reference standard comprising Gram staining of sputum samples and sputum/blood cultures. The area under the curve (AUC) and a log-transformed threshold, which provides the maximal sensitivity and specificity, were calculated. Of 487 subjects enrolled, 129 were evaluable. Receiver operating characteristic curve analysis demonstrated an AUC of 0.87. Sensitivity and specificity were 90.0 percent and 80.0 percent, respectively; positive and negative predictive values were 58.7 percent and 96.2 percent, respectively. We have demonstrated that a quantitative rapid pneumolysin PCR assay has favorable accuracy for diagnosis of pneumococcal pneumonia in adult patients with CAP; this assay may be a useful diagnostic adjunct for clinicians, particularly those practicing in the acute-care setting, where rapid pathogen identification may assist in selection of the most appropriate antibiotics.Streptococcus pneumoniae, the leading cause of communityacquired pneumonia (CAP), accounts for roughly two-thirds of cases in which an etiology can be found (11). Early and accurate diagnosis of pneumococcal pneumonia in the acute-care setting remains difficult due to the limitations of conventional diagnostic methods. Blood and sputum cultures are time-consuming and lack sensitivity (18, 30), particularly for patients with antecedent antibiotic exposure. Sputum culture is also difficult to interpret due to oropharyngeal contamination, and sputum Gram stains are frequently unreliable (2, 10, 17); pleural fluid aspirates are rarely performed. Newer pneumococcal urinary antigen tests offer the promise of improved sensitivity (70 to 82%) but are reported to have variable specificity based on the standards of comparison chosen, the manner in which the test is performed and interpreted, and the particular population studied (6,8,14,20,26). In the absence of a reliable, rapid diagnostic tool, empirical use of broad-spectrum antibiotics is recommended due to the uncertainties of identifying the causative pathogen (2). This approach to patient care results in significant and potentially unnecessary costs...

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confidence: 99%

Quantitative PCR Assay Using Sputum Samples for Rapid Diagnosis of Pneumococcal Pneumonia in Adult Emergency Department Patients

Yang¹,

Lin²,

Khalil³

et al. 2005

J Clin Microbiol

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“…The isolation of S. pneumoniae from blood or pleural fluid, the gold standard test, is positive in only 15-30% of cases [8]. Diagnosis based only on sputum culture is controversial due to both nasopharyngeal carriage of pneumococci in healthy individuals and inadequate sputum specimens [9,10]. In addition,y30% of patients with CAP have been treated with antibiotics before admission, which may decrease the sensitivity of conventional methods [11].…”

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Rapid urinary antigen test for diagnosis of pneumococcal community-acquired pneumonia in adults

Marcos

Anta²,

Bellacasa³

et al. 2003

Eur Respir J

164

127

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Streptococcus pneumoniae is suspected to cause an important proportion of community-acquired pneumonia (CAP) whose aetiology cannot be detected with conventional tests.In this study, the authors evaluated the diagnostic yield of a new immunochromatographic membrane test (ICT) for the detection of the S. pneumoniae antigen in the urine of patients admitted with diagnosed CAP. ICT was performed in unconcentrated and concentrated urine from all the patients. ICT was repeated 1 month after discharge in a group initially testing positive. The authors also studied the ICT in clinically stable human immunodeficiency virus type 1 (HIV1)-infected patients.S. pneumoniae antigen was detected in all of the 68 (100%) patients tested with definitive pneumococcal pneumonia. In five of these cases ICT was only positive when it had been performed on the patients. The S. pneumoniae antigen was also detected in 36 (69.2%) of 52 patients with probable pneumococcal pneumonia and in 50 of 277 (18%) patients without pneumococcal pneumonia. ICT remained positive in 16 (69.5%) of 23 patients, 1 month after hospital discharge. Nasopharyngeal colonisation with S. pneumoniae was detected in 8 (12%) of 68 clinically stable HIV1 infected patients, but none tested ICT positive.The Binax NOW1 immunochromatographic membrane test is a rapid, sensitive and specific test for detecting pneumococcal community-acquired pneumonia in adults. The test may remain positive for several weeks after pneumococcal pneumonia.

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“…In their study this criterion was met in 18 of 29 (62%) specimens from which S pneumoniae was isolated. Others (9) have found that experience is important in the interpretation of the Gram stain-pneumococci tend to be overdiagnosed and H influenzae underdiagnosed by house staff when interpreting Gram stains. House staff performed a Gram stain on 40% of the sputum samples processed for culture at MGH and 28.4% of those at UPMC.…”

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confidence: 99%

Observations from a Multicentre Study on the Use of the Sputum Specimen in Patients Hospitalized with Community‐Acquired Pneumonia

Fine

et al. 1998

Canadian Journal of Infectious Diseases and Medical Microbiolog

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OBJECTIVE:To describe the use of sputum Gram stain and culture in patients with community-acquired pneumonia (CAP) and to determine the factors that are associated with obtaining sputum for culture. TYPE OF STUDY: Prospective observational cohort study of patients hospitalized for treatment of CAP at four medical institutions in three geographic locations. MAIN MEASUREMENTS: Results of Gram stain and culture of sputum; comparison of patients who had sputum processed for culture within 24 h of admission with those who did not have such a specimen processed during the first week of hospitalization; and the results of investigator assignment of etiology of pneumonia according to predefined criteria. RESULTS: Four hundred and seventy-eight of 1339 (36%) patients had a sputum specimen processed for culture within 24 h of admission. Patients who had a sputum specimen processed within 24 h of admission were more likely to be hospitalized at the Boston site (odds ratio [OR] 20.6) or Pittsburgh sites (3.4) and to have current sputum production, chronic obstructive lung disease and moderate or large amount of sputum. Female sex (0.4), neutropenia (0.05), and do not resuscitate status (0.36) were important predictors of failure to have a sputum processed for culture. The rate of Streptococcus pneumoniae isolation was highest in Boston, 53 of 269 (19.3 %) patients (P<0.001) compared with the other sites; Moraxella catarrhalis was isolated only at the Boston site. Sputum culture results served as the basis for the assignment of an etiological diagnosis of the pneumonia by investigators in 67% of 397 patients. CONCLUSIONS: Sputum is not processed for culture in the majority of patients with CAP. The factors that determine whether sputum is processed for culture within 24 h of admission are site of care and a variety of patient factors. Common respiratory pathogens when present in sputum culture tend to be used to assign an etiological diagnosis. A positive sputum culture result appears not to result in a more favourable outcome.

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Evaluation of housestaff physicians’ preparation and interpretation of sputum gram stains for communityacquired pneumonia

Cited by 64 publications

References 16 publications

Quantitative PCR Assay Using Sputum Samples for Rapid Diagnosis of Pneumococcal Pneumonia in Adult Emergency Department Patients

Quantitative PCR Assay Using Sputum Samples for Rapid Diagnosis of Pneumococcal Pneumonia in Adult Emergency Department Patients

Rapid urinary antigen test for diagnosis of pneumococcal community-acquired pneumonia in adults

Observations from a Multicentre Study on the Use of the Sputum Specimen in Patients Hospitalized with Community‐Acquired Pneumonia

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