Stratifying Risk Factors for Multidrug-Resistant Pathogens in Hospitalized Patients Coming From the Community With Pneumonia

Abstract

Risk factors for acquiring MDR bacteria should be weighted differently, and a probabilistic approach to identifying resistant pathogens among patients coming from the community with pneumonia should be embraced.

“Does this patient have…” “Is this patient at risk for infection with multidrug resistant bacteria?”

“…Several other risk factor models have been developed as outlined in Table 1 [7][8][9][10][11][12]. These algorithms were locally developed by investigators, often with the assistance of outside experts, with the primary goal of improving upon the identification of patients with pneumonia attributed to antibiotic-resistant bacteria.…”

Community acquired pneumonia in the elderly: the Pneumonia in Italian Acute Care for Elderly units (PIACE) study protocol by the Italian Society of Hospital and Community Geriatrics (SIGOT)

“…11,12,25 Thus, recent studies have tried to develop new scoring systems to help recognizing pneumonias due to MDR pathogens and the subsequent indication for broad-spectrum empiric therapy. 8,10,28,29 While confirming the predictive role of most HCAP criteria (prior hospitalizations, residence in long-term care facilities, hemodialysis, recent antibiotic use), these studies have proved the value of some typically geriatric features, such as poor functional status, comorbidity, and impaired renal function in identifying patients with MDR pathogens. 8,10,28,29 In older pneumonia populations, a more extensive geriatric assessment, such as that performed in the PIACE study, may help determining the predictive role of other unexplored yet important factors, such as poor nutrition and cognition.…”

“…5,25 Since studies of patients with positive cultures have proved that HCAP is characterized by a higher prevalence of MDR pathogens and worse outcomes than CAP, criteria for HCAP may indeed contribute to identify patients with increased risk for MDR pathogens who should receive this broad-spectrum therapy. [6][7][8][9][10] However, there is increasing recognition that the value of HCAP criteria in identifying pneumonias caused by MDR pathogens is limited, given that many HCAP patients do not have MDR pathogens, with the result of overtreatment without improving outcomes if a broad-spectrum therapy is indiscriminately offered to all HCAP patients. 11,12,25 Thus, recent studies have tried to develop new scoring systems to help recognizing pneumonias due to MDR pathogens and the subsequent indication for broad-spectrum empiric therapy.…”

“…Also, the researcher could describe in the CRF any other additional investigation performed to determine the etiology of pneumonia and a copy of any positive microbiological report had to be uploaded in the e-CRF. The etiology of pneumonia was considered definite if 1 of the following result was obtained: 8,10 When at least 2 of these etiological criteria were found, a polymicrobial infection was diagnosed; patients for whom no etiological investigation was performed, or those with negative results, were considered to have pneumonia of unknown etiology.…”

“…[6][7][8][9][10] It has been argued, however, that up to 75% of HCAP episodes (as calculated in the cohort of patients with etiological microbiological diagnosis) may not be caused by MDR pathogens [9][10][11] and that the use of guidelineconcordant empiric therapy for MDR bacteria may not improve prognosis of HCAP, 12 leading to an overestimation of real risk and antibiotic resistance. Also, outcome of pneumonias (CAP and HCAP) is strongly affected by host and process factors, including older age, 13 failure of initial therapy, 9,13 comorbidity, 1,2,13 impaired mobility, 11 nursing home residency, 13 as well as by the severity of pneumonia [8][9][10]13 and the susceptibility to and adequate management of pneumonia-related complications (mainly acute respiratory failure and sepsis). 1 Consequently, even though older and frail patients frequently correspond to the ATS/IDSA definition of HCAP, it is plausible that the involvement of MDR pathogens or the presence of HCAP criteria do not entirely account for the increased incidence and severity of pneumonia in the elderly.…”