Detection of biofilm in coagulase-negative staphylococcus and its relationship

The capacity of some strains of coagulase-negative Staphylococcus to produce biofilm has been considered by some authors as an index of virulence and serves to differentiate them from contaminating strains. The aim of this study was to determine the relationship between biofilm production and clinical-epidemiological variables, as well as to compare the effectiveness of the congo red agar medium for its diagnosis with the one conventionally used in our laboratory. For this purpose, an observational, analytical and cross-sectional study was carried out during the period January-December 2012 in the Microbiology laboratory of the "Saturnino Lora" Provincial Hospital. The universe consisted of 107 strains of coagulase-negative staphylococcus that grew in catheter and blood culture samples from patients admitted to the Intensive Care, Cardiology, Nephrology and Cardiocenter wards; for the detection of biofilm, the congo red agar medium and the mucus test were applied. It is concluded that coagulase-negative staphylococcus infection is frequent in these patients, that in them advanced age, the presence of coagulase-negative staphylococcus and especially diabetes mellitus are factors to be taken into account. It was demonstrated that congo red agar medium, due to its simplicity, high sensitivity and specificity, can be added to the diagnostic arsenal of our laboratories for the detection of biofilm.