IntroductionCulture-negative sepsis is a common but relatively understudied condition. The aim of this study was to compare the characteristics and outcomes of culture-negative versus culture-positive severe sepsis.MethodsThis was a prospective observational cohort study of 1001 patients who were admitted to the medical intensive care unit (ICU) of a university hospital from 2004 to 2009 with severe sepsis. Patients with documented fungal, viral, and parasitic infections were excluded.ResultsThere were 415 culture-negative patients (41.5%) and 586 culture-positive patients (58.5%). Gram-positive bacteria were isolated in 257 patients, and gram-negative bacteria in 390 patients. Culture-negative patients were more often women and had fewer comorbidities, less tachycardia, higher blood pressure, lower procalcitonin levels, lower Acute Physiology and Chronic Health Evaluation II (median 25.0 (interquartile range 19.0 to 32.0) versus 27.0 (21.0 to 33.0), P = 0.001) and Sequential Organ Failure Assessment scores, less cardiovascular, central nervous system, and coagulation failures, and less need for vasoactive agents than culture-positive patients. The lungs were a more common site of infection, while urinary tract, soft tissue and skin infections, infective endocarditis and primary bacteremia were less common in culture-negative than in culture-positive patients. Culture-negative patients had a shorter duration of hospital stay (12 days (7.0 to 21.0) versus 15.0 (7.0 to27.0), P = 0.02) and lower ICU mortality than culture-positive patients. Hospital mortality was lower in the culture-negative group (35.9%) than in the culture-positive group (44.0%, P = 0.01), the culture-positive subgroup, which received early appropriate antibiotics (41.9%, P = 0.11), and the culture-positive subgroup, which did not (55.5%, P < 0.001). After adjusting for covariates, culture positivity was not independently associated with mortality on multivariable analysis.ConclusionsSignificant differences between culture-negative and culture-positive sepsis are identified, with the former group having fewer comorbidities, milder severity of illness, shorter hospitalizations, and lower mortality.

Background: The 2007 Infectious Disease Society of America (IDSA)/American Thoracic Society (ATS) guidelines defined severe community-acquired pneumonia (CAP) and recommended intensive care unit (ICU) admission when patients fulfilled three out of nine minor criteria. These criteria have not been validated. Methods: All patients admitted to our hospital from 2004 to 2007 for CAP were reviewed retrospectively. Patients who fulfilled any IDSA/ATS major criteria for severe CAP at the emergency department (ie, the need for mechanical ventilation or vasopressors) were excluded. The predictive characteristics of the IDSA/ATS minor criteria were compared with those of the Pneumonia Severity Index (PSI) and the CURB-65 score for hospital mortality and ICU admission. Results: 1242 patients were studied (mean age 65.7 years, hospital mortality 14.7%). The areas under the receiver operating characteristic curves for the IDSA/ATS minor criteria were 0.88 (95% CI 0.86 to 0.91) and 0.85 (95% CI 0.81 to 0.88) for predicting hospital mortality and ICU admission, respectively. These were greater than the corresponding areas for the PSI and the CURB-65 score (p,0.05). The sensitivity, specificity, positive and negative predictive values of the minor criteria were 81.4%, 82.9%, 45.2% and 96.3%, respectively, for hospital mortality and 58.3%, 90.6%, 52.9% and 92.3%, respectively, for ICU admission. The minor criteria were more specific than the PSI and more sensitive than the CURB-65 score for both outcomes. Conclusion: These findings support the use of the IDSA/ ATS minor criteria to predict hospital mortality and guide ICU admission in inpatients with CAP who do not require emergency mechanical ventilation or vasopressors.

The primary objective of the present study was to evaluate the effect on hospital mortality of a delay in intensive care unit (ICU) admission for severe community-acquired pneumonia (CAP). The secondary objectives were to assess if such delays were associated with treatment variations by the emergency department (ED) and deterioration in the general wards, and to evaluate the prognostic ability of the Infectious Disease Society of America (IDSA)/ American Thoracic Society (ATS) minor criteria.We retrospectively compared patients who were admitted straight from the ED to the ICU (direct group, n554) and those who were first admitted from the ED to the general wards before ICU transfer (delayed group, n549), over 2.5 yrs.Even after excluding patients who required mechanical ventilation and/or vasopressors at the ED, delayed ICU admission was an independent predictor of hospital mortality (OR 9.61). The delayed group received fewer fluid boluses in the ED and rapidly deteriorated in the general wards. The presence of o3 IDSA/ATS minor criteria was associated with increased mortality in the delayed group.In conclusion, prompt recognition of severe CAP using the IDSA/ATS minor criteria, followed by aggressive management at the ED and direct ICU admission, are all crucial toward improving outcomes.

The effect of employing severity scores to identify severe community-acquired pneumonia (SCAP) cases for early aggressive resuscitation is unknown. Optimising pre-intensive care unit (ICU) care may improve outcomes in patients at risk of SCAP.We conducted a before-and-after study of patients classified into control and intervention groups (January 2004 to December 2007 and January 2008 to December 2010, respectively). Our intervention was two-pronged, using the 2007 Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) minor criteria to identify SCAP for aggressive emergency department resuscitation. Patients with SCAP, defined as those with three or more IDSA/ATS minor criteria, were targeted. Differences in mortality, triage and compliance with emergency department resuscitation were compared between the groups.The hospital mortality rate was lower in the intervention versus the control group (5.7% versus 23.8%, p,0.001). On multivariate analysis, the intervention group was associated with lower mortality (OR 0.24, 95% CI 0.09-0.67). ICU admission rates decreased from 52.9% to 38.6% (p50.008) and inappropriately delayed ICU admissions decreased from 32.0% to 14.8% (p,0.001). There was increased compliance with the aggressive resuscitation protocol after the intervention.A combined intervention, using a pneumonia score to identify those at risk of SCAP early and an aggressive pre-ICU resuscitation protocol may reduce mortality and ICU admissions. @ERSpublications IDSA/ATS minor criteria can help identify at-risk SCAP patients for early resuscitation

Background: Pathogens are often not identified in severe community-acquired pneumonia (CAP), and the few studies using polymerase chain reaction (PCR) techniques for virus detection are from temperate countries. Objective: This study assesses if PCR amplification improves virus and bacteria detection, and if viral infection contributes to mortality in severe CAP in a tropical setting, where respiratory pathogens have less well-defined seasonality. Methods: In this cohort study of patients with severe CAP in an intensive care unit, endotracheal aspirates for intubated patients and nasopharyngeal swabs for non-intubated patients were sent for PCR amplification for respiratory viruses. Blood, endotracheal aspirates for intubated patients, and sputum for non-intubated patients were analysed using a multiplex PCR system for bacteria. Results: Out of 100 patients, using predominantly cultures, bacteria were identified in 42 patients; PCR amplification increased this number to 55 patients. PCR amplification identified viruses in 32 patients. In total, only bacteria, only viruses, and both bacteria and viruses were found in 37, 14, and 18 patients, respectively. The commonest viruses were influenza A H1N1/2009 and rhinovirus; the commonest bacterium was Streptococcus pneumoniae. Hospital mortality rates for patients with no pathogens, bacterial infection, viral infection, and bacterial-viral co-infection were 16.1, 24.3, 0, and 5.6%, respectively (p = 0.10). On multivariable analysis, virus detection was associated with lower mortality (adjusted odds ratio 0.12, 95% confidence interval 0.2-0.99; p = 0.049). Conclusions: Viruses and bacteria were detected in 7 of 10 patients with severe CAP with the aid of PCR amplification. Viral infection appears to be independently associated with lower mortality.

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