Bacteraemia and antibiotic-resistant pathogens in community acquired pneumonia: risk and prognosis

Abstract

The sensitivity of blood cultures in the diagnosis of bacteraemia for community-acquired pneumonia is low. Recommendations, by guidelines, to perform blood cultures are discordant. We aimed to determine the incidence, microbial aetiology, risk factors and outcomes of bacteraemic patients with community-acquired pneumonia, including cases with antibiotic-resistant pathogens (ARP).A prospective, observational study was undertaken on consecutive adult patients admitted to the Hospital Clinic of Barcelona (Barcelona, Spain) with community-acquired pneumonia and blood cultures were obtained.Of the 2892 patients included, bacteraemia was present in 297 (10%) patients; 30 (10%) of whom had ARP (multidrug-resistant Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and an extended spectrum of beta-lactamase producing Enterobacteriaceae). In multivariate analyses, pleuritic pain, C-reactive protein ⩾21.6 mg·dL −1 and intensive care unit admissions were independently associated with bacteraemia, while prior antibiotic treatment and pneumococcal vaccine were protective factors. The risk factors for ARP bacteraemia were previous antibiotics and C-reactive protein <22.2 mg·dL −1 , while pleuritic pain was the only protective factor in the multivariate analysis. Bacteraemia (excluding ARP), appropriate empiric treatment, neurological disease, arterial oxygen tension/inspiratory oxygen fraction <250, pneumonia severity index risk classes IV and V, and intensive care unit admission were independently associated with a 30-day hospital mortality in the multivariate analysis. Inappropriate therapy was more frequent in ARP bacteraemia, compared with other bacteraemias (27% versus 3%, respectively, p<0.001).Antibiotic therapy protected against bacteraemia, but increased specifically the risk of bacteraemia from ARP due to the inappropriate coverage of these pathogens. Identifying patients at risk of ARP bacteraemia would help in deciding appropriate empiric antimicrobial therapy. The results from this study provide evidence concerning community-acquired pneumonia patients in whom blood cultures should not be performed. @ERSpublications Understand risk factors for ARP bacteraemia and the importance of identifying patients who may have these organisms

Prognostic factors in hospitalized community-acquired pneumonia: a retrospective study of a prospective observational cohort

“…Previous reports have shown that CAP patients with bacteremia [7] or multilobar pneumonia [8] have a worse prognosis; therefore, we included these variables in the analysis.…”

Microbial Etiology of Pneumonia: Epidemiology, Diagnosis and Resistance Patterns

“…An important study on bacteremia caused by antibiotic-resistant pathogens (ARP) in CAP [80] reported that the risk factors for ARP bacteremia in CAP patients were; previous antibiotic use and C-reactive protein < 22.2 mg/dL. The authors also reported that inappropriate therapy was more frequent in ARP bacteremia compared with other bacteremias (27% and 3%, respectively, p < 0.001).…”

Predictive factors for true bacteremia and clinical utility of blood cultures as a prognostic tool in patients with community-onset pneumonia

“…[31,37] This is 1 reason why the guidelines did not refer to whether BCs should be performed in HCAP patients. [1,[9][10][11] Our study found that HCAP was not a predictive factor of TB, and the rates of change in antibiotic therapy did not differ between CAP and HCAP.…”

“…[36] In contrast, a recent prospective, observational study revealed a relatively high rate of ARP bacteremia in CAP (30/2892 patients; 1.0%). [37] In our Table 2 Microorganisms identified from blood cultures in patients with community-onset pneumonia. Relationship between severity of pneumonia and true bacteremia.…”