Guillermo Martín-Gutiérrez1, Carlos Martín-Pérez2, Antonio Gutiérrez-Pizarraya3, José A Lepe4, José M Cisneros4, Javier Aznar5. 1. Infectious Diseases, Clinical Microbiology and Preventive Medicine Unit, Virgen Macarena and Virgen del Rocío University Hospitals, Calle Manuel Siurot s/n, 41013 Seville, Spain; Institute of Biomedicine of Seville (IBiS), Virgen del Rocío, Calle Manuel Siurot s/n, 41013 Seville, Spain. Electronic address: guiller_mg86@hotmail.es. 2. Centro de Salud Marquesado, Área Nordeste de Granada, Carretera los Pozos, 2, Alquife, 18518 Granada, Spain. 3. Institute of Biomedicine of Seville (IBiS), Virgen del Rocío, Calle Manuel Siurot s/n, 41013 Seville, Spain; Spanish Clinical Research Network, Virgen del Rocío University Hospital, Calle Manuel Siurot s/n, 41013 Seville, Spain. 4. Infectious Diseases, Clinical Microbiology and Preventive Medicine Unit, Virgen Macarena and Virgen del Rocío University Hospitals, Calle Manuel Siurot s/n, 41013 Seville, Spain; Institute of Biomedicine of Seville (IBiS), Virgen del Rocío, Calle Manuel Siurot s/n, 41013 Seville, Spain. 5. Infectious Diseases, Clinical Microbiology and Preventive Medicine Unit, Virgen Macarena and Virgen del Rocío University Hospitals, Calle Manuel Siurot s/n, 41013 Seville, Spain; Institute of Biomedicine of Seville (IBiS), Virgen del Rocío, Calle Manuel Siurot s/n, 41013 Seville, Spain; Microbiology Department, University of Seville, Avda. Sánchez Pizjuan, s/n, 41009 Seville, Spain.
Abstract
OBJECTIVE: The time to positivity (TTP) of blood cultures in patients with bloodstream infections (BSIs) has been considered to be a possible prognostic tool for some bacterial species. However, notable differences have been found between sampling designs and statistical methods in published studies to date, which makes it difficult to compare results or to derive reliable conclusions. Our objective was to evaluate the clinical and microbiological implications of TTP among patients with BSI caused by the most common pathogens. METHODS: A total of 361 episodes of BSI were reported for 332 patients. The survival of the entire cohort was measured from the time of blood culture sampling. In order to compare our results with those of previous studies, TTP was divided in three different groups based on log rank (short TTP <12h; medium TTP ≥12h to ≤27h, and long TTP >27h). Cox proportional hazard models were used to calculate crude and adjusted hazard ratios (HR). RESULTS: The Cox proportional hazard model revealed that TTP is an independent predictor of mortality (HR=1.00, p=0.031) in patients with BSIs. A higher mortality was found in the group of patients with the shortest TTP (<12h) (HR=2.100, p=0.047), as well as those with longest TTP (>27h) (HR=3.277, p=0.031). CONCLUSIONS: It seems that TTP may provide a useful prognostic tool associated with a higher risk of mortality, not only in patients with shorter TTP, but also in those with longer TTP.
OBJECTIVE: The time to positivity (TTP) of blood cultures in patients with bloodstream infections (BSIs) has been considered to be a possible prognostic tool for some bacterial species. However, notable differences have been found between sampling designs and statistical methods in published studies to date, which makes it difficult to compare results or to derive reliable conclusions. Our objective was to evaluate the clinical and microbiological implications of TTP among patients with BSI caused by the most common pathogens. METHODS: A total of 361 episodes of BSI were reported for 332 patients. The survival of the entire cohort was measured from the time of blood culture sampling. In order to compare our results with those of previous studies, TTP was divided in three different groups based on log rank (short TTP <12h; medium TTP ≥12h to ≤27h, and long TTP >27h). Cox proportional hazard models were used to calculate crude and adjusted hazard ratios (HR). RESULTS: The Cox proportional hazard model revealed that TTP is an independent predictor of mortality (HR=1.00, p=0.031) in patients with BSIs. A higher mortality was found in the group of patients with the shortest TTP (<12h) (HR=2.100, p=0.047), as well as those with longest TTP (>27h) (HR=3.277, p=0.031). CONCLUSIONS: It seems that TTP may provide a useful prognostic tool associated with a higher risk of mortality, not only in patients with shorter TTP, but also in those with longer TTP.