Wound contamination in cardiac surgery. A systematic quantitative and qualitative study of the bacterial growth in sternal wounds in cardiac surgery patients.
OBJECTIVE
To investigate the degree of bacterial contamination in the sternal wound during cardiac surgery and the sternal skin flora after operation in order to increase our understanding of the pathogenesis of sternal wound infections.


METHODS
Prospective study where cultures were taken peri- and postoperatively from sternal wounds and skin.


METHODS
University Hospital.


METHODS
201 cardiac surgery patients.


RESULTS
89% of the patients grew bacteria from the subcutaneous sternal tissue. 98% of the patients showed bacterial growth on the surrounding skin at the end of the operation. We found both commensal and nosocomial bacteria in the sternal wound. These bacteria had different temporal distribution patterns. Coagulase-negative staphylococci (CoNS) and Propionibacterium acnes (PA) were by far the most prevalent bacteria during and after the operation. Furthermore, 41% of patients had more than 10,000 CFU/pad CoNS on the skin. There was no correlation between length of operation and number of bacteria. Men displayed higher bacterial counts than women on the skin.


CONCLUSIONS
Skin preparation with ethanol/chlorhexidine is unable to suppress the physiological skin flora for the duration of a heart operation. A decrease of CoNS and PA postoperatively can be caused by competitive recolonisation of commensal and nosocomial bacteria.
Kühme
Tobias
T
Department of Vascular Diseases Malmö-Lund, Malmö University Hospital, Malmö, Sweden. tobias.kuhme@skane.se
Isaksson
Barbro
B
Dahlin
Lars-Göran
LG
D000368:Aged; D006348:Cardiac Surgical Procedures; D015169:Colony Count, Microbial; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000209:etiology / Q000382:microbiology*; D016908:Gram-Positive Bacterial Infections / Q000209:etiology / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011425:Propionibacterium acnes / Q000254:growth & development; D011446:Prospective Studies; D012867:Skin / Q000382:microbiology; D013211:Staphylococcus aureus / Q000254:growth & development; D018709:Statistics, Nonparametric; D013249:Sternum / Q000601:surgery; D013530:Surgical Wound Infection / Q000382:microbiology*