Methods: Retrospective descriptive study (Jan/2014 - Sept/2016). 138 records were collected from the blood culture Severo Ochoa University Hospital registry. 31 cases with <8 weeks of difference between them and 9 with incompleted data, were excluded. 98 cases were analyzed through electronic clinical records. Microbiological analysis of Vancomycin MIC was performed using a microdilution technique. Statistical analysis was performed using SPSS 20.0 package using: Shapiro-Wilk, χ2, U of Mann Whitney, logistic regression and Kaplan Meier.
Results: The mean age was 71.41 with 59.2% of men and 40.8% of women. 63.3% of the patients had a Charlson comorbidity index≥6. A total of a 26.53% were carriers of a venous central catheter (VVC).The most frequent source of bacteremia was VVC with 26.5%, followed by primary bacteremia (22.4%), osteoarticular site (13.3%) and peripheral catheter (11.2%). The 77.55% of the episodes were health care related and 52.04% were nosocomial. A 41.8% of the patients had a complicated evolution but only a 14.24% were directly attributable to bacteremia. The 23.5% of patients needed admission in ICU. The admission in ICU was related with the delay in starting the correct antibiotic therapy (p= 0.06).The global mortality rate at 30 days was 25.5% and the related mortality rate at 30 days was 18.4%. The 43.87% of the S. aureus had a MIC≥2 to Vancomycin (20 MRSA and 23 MSSA). The Vancomycin MIC≥2 was significantly associated with persistent bacteremia (p = 0.05), this statistic trend is maintained in the subgroup of MSSA (p = 0.09), but not in the subgroup MRSA (p = 0.56). There was no significant association between Vancomycin MIC ≥ 2 with high Charlson's comorbidity index, direct complications or related mortality.
Conclusion: Vancomycin MIC≥2 may be a useful parameter in daily clinical practice as a marker of poor clearance of bacteremia (p=0.05). In our series, this trend is maintained in MSSA subgroup but not in MRSA subgroup.
R. Núñez, None
M. Cervero, None