Bacteremia por Staphylococcus coagulasa negativo con concentración inhibitoria mínima para vancomicina ≥ 2

Bacteremia in the red blood cells obtained from the cell saver in patients submitted to heart surgery

OBJECTIVE

to determine the microbiological characteristics of the red blood cells obtained with the cell saver in heart surgery patients on an extra-body circuit.

METHOD

a cross-sectional and descriptive study conducted with 358 patients scheduled for heart surgery where the saver was used. Sociodemographic variables were collected, as well as from the saver and of the microbial identification in the re-infusion bag proceeding from the cell saver. Informed consent performed.

RESULTS

of the 170 GRAM+ bacteria isolations, the most frequent species were Staphylococcus epidermidis in 69% (n=138) of the cases and Streptococcus sanguinis with a report of 10% (n=20). Significant differences were found in the Staphylococcus epidermidis strain in patients with a Body Mass Index ≥25 (p=0.002) submitted to valve surgery (p=0.001). Vancomycin was the antimicrobial which resisted the Staphylococcus epidermidis strain with a minimum inhibitory concentration of >16 µg/ml.

CONCLUSION

the microbiological characteristics of the red blood cells obtained after processing autologic blood recovered with the cell saver during heart surgery are of GRAM+ bacterial origin, the most isolated species being Staphylococcus epidermidis. Consequently, in order to reduce the presence of these GRAM+ cocci, an antibiotic should be added to the cell saver reservoir, according to a previously established protocol.

Violacein antimicrobial activity on Staphylococcus epidermidis and synergistic effect on commercially available antibiotics

AIMS

The study aimed to assess whether violacein has antimicrobial activity on Staphylococcus epidermidis and synergistically modulates the action of commercially available antimicrobial drugs.

METHODS AND RESULTS

Violacein showed excellent antimicrobial activity on biofilm-forming and nonbiofilm-forming S. epidermidis strains (ATCC 35984) (ATCC 12228), with bacteriostatic (MIC = 20 μg ml^-1 and 10 μg ml^-1 respectively) and bactericidal effects (MBC = 20 μg ml^-1 for both strains), observed in short periods of exposure. The violacein bactericidal concentration led to S. epidermidis death after 2-3 h of exposure. Additionally, violacein synergistically modulated the activity of different antimicrobial classes on S. epidermidis ATCC 12228 (81·8%; n = 9) and on S. epidermidis ATCC 35984 (54·5%; n = 6), reducing the MIC of these antibiotics by up to 16-fold.

CONCLUSION

Violacein shows excellent antimicrobial activity on S. epidermidis strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

Violacein shows the potential for the development of a new drug for the treatment of infections caused by S. epidermidis.