MALDI-TOF is not useful in the diagnosis of catheter colonization based on superficial cultures: results from an in vitro study.
We compared in an vitro model the yields of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and conventional culture (CC) for the detection of catheter colonization with superficial catheter samples (SS). We used blood culture bottles (BCB) with an inserted cannula and incubated at 37 °C. The BCB were manipulated with different contaminations and when a BCB turned positive, SS were obtained to perform both techniques. To compare both techniques we analyzed the mean time to colonization (MTC) and the mean time to a result (MTR). The MTC (SD, days) by CC and MALDI-TOF was as follows: hub, 0.59 (0.79) versus 1.07 (1.39), P=0.06; surface: 0.62 (0.67) versus 0.82 (0.81), P<0.001. The MTR (SD, days) of CC and MALDI-TOF was as follows: hub: 1.58 (0.79) versus 2.25 (1.48), P=0.04; surface: 1.62 (0.67) versus 1.95 (0.80), P<0.001. In general, the use of MALDI-TOF performed directly with SS was no better than CC and did not anticipate colonization results.
Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain. Electronic address: mariaguembe@hotmail.com.
María
M
Guembe
CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain; Cardiac Surgery Postoperative Care Unit, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
María Jesús
MJ
Pérez-Granda
Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.
Raquel
R
Cruces
Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.
Belén
B
Rodríguez-Sánchez
Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Adrián
A
Ruíz
Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Luis
L
Alcalá
Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain; CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain; Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.
Emilio
E
Bouza
D062905:Central Venous Catheters / Q000382:microbiology*; D006801:Humans; D008828:Microbiological Techniques / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013696:Temperature
Central venous catheters; Colonization; Hub culture; In vitro model; MALDI-TOF; Skin culture; Superficial cultures