Advances in molecular diagnostic tests for pneumonia.

PURPOSE OF REVIEW: Pneumonia is the main global cause of sepsis, and has been associated with high morbidity and high short and long-term mortality rates. As it may be caused by a wide spectrum of microorganisms, microbial diagnosis is challenging and the choice of adequate therapy remains an important problem. This review focuses on recently published studies of microbiological diagnostic tests and clinical assessments for pneumonia, including community-acquired pneumonia, hospital-acquired pneumonia, and ventilator-associated pneumonia. RECENT FINDINGS: Over the past decade, the microbiological diagnosis of pneumonia has improved significantly - thanks to the development and implementation of molecular diagnostic tests for identifying the most frequent pathogens causing pneumonia and for determining their patterns of resistance. Molecular methods for the diagnosis of pneumonia focus on multiple target detection systems and pathogen detection arrays, and, more recently, have been used in combination with mass spectrometry. SUMMARY: The implementation of rapid diagnostic techniques in routine clinical practice able to identify and determine the resistance patterns of the causative microbes may transform the management of pneumonia, improving the selection and administration of antimicrobial therapies especially in critically ill patients. The validation of new diagnostic technology platforms is crucial in order to assess their usefulness and to guide antimicrobial treatment in this population.

Acute respiratory distress syndrome in mechanically ventilated patients with community-acquired pneumonia.

Our aim was to assess the incidence, characteristics, aetiology, risk factors and mortality of acute respiratory distress syndrome (ARDS) in intensive care unit (ICU) patients with community-acquired pneumonia (CAP) using the Berlin definition.We prospectively enrolled consecutive mechanically ventilated adult ICU patients with CAP over 20 years, and compared them with mechanically ventilated patients without ARDS. The main outcome was 30-day mortality.Among 5334 patients hospitalised with CAP, 930 (17%) were admitted to the ICU and 432 required mechanical ventilation; 125 (29%) cases met the Berlin ARDS criteria. ARDS was present in 2% of hospitalised patients and 13% of ICU patients. Based on the baseline arterial oxygen tension/inspiratory oxygen fraction ratio, 60 (48%), 49 (40%) and 15 (12%) patients had mild, moderate and severe ARDS, respectively. Streptococcus pneumoniae was the most frequent pathogen, with no significant differences in aetiology between groups. Higher organ system dysfunction and previous antibiotic use were independent risk factors for ARDS in the multivariate analysis, while previous inhaled corticosteroids were independently associated with a lower risk. The 30-day mortality was similar between patients with and without ARDS (25% versus 30%, p=0.25), confirmed by propensity-adjusted multivariate analysis.ARDS occurs as a complication of CAP in 29% of mechanically ventilated patients, but is not related to the aetiology or mortality.

The Effect of Macrolide Resistance on the Presentation and Outcome of Patients Hospitalized for Streptococcus pneumoniae Pneumonia.

RATIONALE: There are conflicting reports describing the effect of macrolide resistance on the presentation and outcomes of patients with Streptococcus pneumoniae pneumonia. OBJECTIVES: We aimed to determine the effect of macrolide resistance on the presentation and outcomes of patients with pneumococcal pneumonia. METHODS: We conducted a retrospective, observational study in the Hospital Clinic of Barcelona of all adult patients hospitalized with pneumonia who had positive cultures for S. pneumoniae from January 1, 2000 to December 31, 2013. Outcomes examined included bacteremia, pulmonary complications, acute renal failure, shock, intensive care unit admission, need for mechanical ventilation, length of hospital stay, and 30-day mortality. MEASUREMENTS AND MAIN RESULTS: Of 643 patients hospitalized for S. pneumoniae pneumonia, 139 (22%) were macrolide resistant. Patients with macrolide-resistant organisms were less likely to have bacteremia, pulmonary complications, and shock, and were less likely to require noninvasive mechanical ventilation. We found no increase in the incidence of acute renal failure, the frequency of intensive care unit admission, the need for invasive ventilatory support, the length of hospital stay, or the 30-day mortality in patients with (invasive or noninvasive) macrolide-resistant S. pneumoniae pneumonia, and no effect on outcomes as a function of whether treatment regimens did or did not comply with current guidelines. CONCLUSIONS: We found no evidence suggesting that patients hospitalized for macrolide-resistant S. pneumoniae pneumonia were more severely ill on presentation or had worse clinical outcomes if they were treated with guideline-compliant versus noncompliant regimens.

Risk and Prognostic Factors in Very Old Patients with Sepsis Secondary to Community-Acquired Pneumonia.

BACKGROUND: Little is known about risk and prognostic factors in very old patients developing sepsis secondary to community-acquired pneumonia (CAP). Methods: We conducted a retrospective observational study of data prospectively collected at the Hospital Clinic of Barcelona over a 13-year period. Consecutive patients hospitalized with CAP were included if they were very old (≥80 years) and divided into those with and without sepsis for comparison. Sepsis was diagnosed based on the Sepsis-3 criteria. The main clinical outcome was 30-day mortality. Results: Among the 4219 patients hospitalized with CAP during the study period, 1238 (29%) were very old. The prevalence of sepsis in this age group was 71%. Male sex, chronic renal disease, and diabetes mellitus were independent risk factors for sepsis, while antibiotic therapy before admission was independently associated with a lower risk of sepsis. Thirty-day and intensive care unit (ICU) mortality did not differ between patients with and without sepsis. In CAP-sepsis group, chronic renal disease and neurological disease were independent risk factors for 30-day mortality. Conclusion: In very old patients hospitalized with CAP, in-hospital and 1-year mortality rates were increased if they developed sepsis. Antibiotic therapy before hospital admission was associated with a lower risk of sepsis.