Acute dehiscence of a valve prosthesis 5 years after implantation

Bacterial recolonization of the skin and wound contamination during cardiac surgery: a randomized controlled trial of the use of plastic adhesive drape compared with bare skin

BACKGROUND

Sternal wound infection after cardiac surgery is a serious complication. Various perioperative strategies, including plastic adhesive drapes, are used to reduce bacterial contamination of surgical wounds.

AIM

To compare plastic adhesive drape to bare skin regarding bacterial growth in wound and time to recolonization of the adjacent skin intraoperatively, in cardiac surgery patients.

METHODS

This single-blinded randomized controlled trial (May 2010 to May 2011) included 140 patients scheduled for cardiac surgery via median sternotomy. The patients were randomly allocated to the adhesive drape (chest covered with plastic adhesive drape) or bare skin group. Bacterial samples were taken preoperatively and intraoperatively every hour during surgery until skin closure.

RESULTS

Disinfection with 0.5% chlorhexidine solution in 70% alcohol decreased coagulase-negative staphylococci (CoNS), while the proportion colonized with Propionibacterium acnes was not significantly reduced and was still present in more than 50% of skin samples. P. acnes was significantly more common in men than in women. Progressive bacterial recolonization of the skin occurred within 2-3 h. At 120 min there were significantly more positive cultures in the adhesive drape group versus bare skin group for P. acnes (63% vs 44%; P = 0.034) and for CoNS (45% vs 24%; P = 0.013). The only statistically significant difference in bacterial growth in the surgical wound was higher proportion of CoNS at the end of surgery in the adhesive drape group (14.7% vs 4.4%; P = 0.044).

CONCLUSION

Plastic adhesive drape does not reduce bacterial recolonization. P. acnes colonized men more frequently, and was not decreased by disinfection with chlorhexidine solution in alcohol.

Propionibacterium acnes endocarditis of a prosthetic aortic valve

In the few reported cases of Propionibacterium infective endocarditis involving prosthetic aortic valves, abscess is common and frequently requires surgery. We report a case of P. acnes infective endocarditis identified on prolonged blood cultures with aortic root abscess involving a Starr-Edwards valve. Intravenous antibiotics and valve replacement led to recovery.

Chronic prosthetic valve endocarditis due to Propionibacterium acnes: an unexpected cause of prosthetic valve dysfunction

INTRODUCTION AND OBJECTIVES

To determine the characteristics of Propionibacterium acnes prosthetic valve endocarditis (PAPVE).

METHODS

Prospective descriptive study of 16 consecutive cases of PAPVE.

RESULTS

Seven patients developed PAPVE early and 9 developed it late. In all those who developed PAPVE late, there was a history of mucocutaneous barrier manipulation. The delay in diagnosis was >3 months in 75%. The clinical presentation was asymptomatic prosthetic valve dysfunction in 31%, heart failure in 19%, coronary syndrome in 12.5%, fever in 25%, and neurological deficits in 19%. At diagnosis, 62.5% had heart failure and 44% had fever. The predominant echocardiographic finding was prosthesis dysfunction due to dehiscence of metallic aortic valves (6 out of 7) or stenosis of metallic mitral valves (4 out of 7). In 2 of the 3 biological aortic prostheses, dysfunction was due to leaflet distortion. Blood cultures and surgical specimens tested positive after a mean of 11.6 and 12.2 days, respectively. In 2 cases, the diagnosis was confirmed by PCR. The principle intraoperative finding was the presence of abundant grayish pannus. Histology demonstrated the absence of acute inflammatory features. Twelve patients received antibiotic treatment with valve replacement: 7 were cured, 4 experienced early prosthesis dehiscence and 1 relapsed. All 3 patients who were initially treated with antibiotics alone suffered relapses.

CONCLUSIONS

Generally, PAPVE presents as prosthetic valve dysfunction with few symptoms of infection. Prolonged incubation of cultures is essential for diagnosis. Antibiotic treatment provides clinical control but does not eradicate the infection, and valve replacement is necessary for a cure. The postoperative course can be complicated by prosthesis dehiscence.

Infective endocarditis due to Propionibacterium species

Propionibacterium species rarely cause infective endocarditis. When identified in blood cultures, they may be inappropriately disregarded as skin flora contaminants. The purpose of this study was to characterize the clinical presentation and management of endocarditis due to Propionibacterium species. All cases of endocarditis due to Propionibacterium species that were treated at the Mayo Clinic, Rochester, USA were retrospectively reviewed, and the English language medical literature was searched for all previously published reports. Seventy cases, which included eight from the Mayo Clinic, were identified (clinical details were available for only 58 cases). The median age of patients was 52 years, and 90% were males. In 79% of the cases, the infection involved prosthetic material (39 prosthetic valves, one left ventricular Teflon patch, one mitral valve ring, one pulmonary artery prosthetic graft, three pacemakers, and one defibrillator). Blood cultures were positive in 62% of cases. All 22 cases with negative blood cultures were microbiologically confirmed by either positive valve tissue cultures (n = 21) or molecular methods (n = 1). Endocarditis was complicated by abscess formation in 36% of cases. The majority (81%) of patients underwent surgery, either for valve replacement and debridement of a cardiac abscess, or removal of an infected device. Crude in-hospital mortality was 16%. The median duration of postoperative antibiotic treatment was 42 days. Patients were commonly treated with a penicillin derivative alone or in combination with gentamicin. On the basis of the above data, it is recommended that infective endocarditis should be strongly suspected when Propionibacterium species are isolated from multiple blood cultures, particularly in the presence of a cardiovascular device.