Fungal Agents as a Cause of Surgical Wound Infections: An Overview of Host Factors
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Surgical infections (SIs) are infections of the tissues, organs or spaces, exposed by surgeons during performance of an invasive procedure. The development of SIs is related to 3 factors; the degree of microbial contamination of the wound during surgery, the duration of the procedure and host factors, such as diabetes, malnutrition, obesity, immunosuppression, and the number of other underlying disease states.1
SIs are associated with considerable morbidity and occasional lethality, as well as substantial healthcare costs and patient inconvenience and dissatisfaction.2 For that reason surgeons strive to avoid SIs by the use of mechanical, chemical and antimicrobial modalities, or a combination of these methods for prophylaxis.
Bacteria are responsible for the majority of surgical infections. Gram-positive bacteria that frequently cause infections in surgical patients include aerobic skin commensals and enteric organisms. There are many pathogenic gram-negative bacterial species that are capable of causing surgical infections, predominantly members of the Enterobacteriaceae family. Anaerobic bacteria, fungi, and viruses are the other causes of SIs. Fungi cause nosocomial infections in surgical patients as a part of polymicrobial infections or fungemia, rare causes of aggressive soft tissue infections and so-called opportunistic pathogens.1
The aim of this study was to evaluate the fungal agents as a cause of SIs, and to discuss the host factors predisposing the infection.
Methods
The study was carried out in the laboratory of Microbiology Department of Medical Faculty of Duzce University. Culturing results of surgical wound infections between January 2001 and December 2005 were evaluated. A total of 824 samples were sent to the laboratory from surgical clinics during this period.
The specimens were obtained by using sterile swabs and immediately inserted in Dio-Transport swab/Stuart medium (Diomed Inc, Istanbul, Turkey) and sent to the laboratory. All samples were inoculated onto 5% sheep blood agar, Eosin Methylene Blue (EMB) agar and Sabouraud Dextrose Agar (SDA)’s and Gram, EZN and Giemsa staining procedures were applied for all samples. Plates were incubated for 24–48 hours and than examined. Growth was obtained and conventional microbiological methods and the API System (bioMérieux, Marcy l’Étoile, France) were used to identify the organism. The results were interpreted parallel to the staining results.
Results
A total of 824 samples including all submitted surgical specimens were evaluated and organisms were recovered from 455 (55.2%) of the samples. Of 455 isolates, 443 (97.4 %) were bacteria, 12 (2.6%) were fungi, 47 (10.3%) bacteria, and 9 (2%) fungi were isolated as the cause of SIs. Fungal growth was obtained as pure cultures. As a result of identification of these fungi, all were yeasts. Five (55.6%) were identified as Candida albicans, 3 (33.3%) as Candida tropicalis, and 1 (11.1%) as Candida glabrata.
Fungal growth was obtained in 9 specimens of the patients who have at least 1 predisposing factor to fungal infections. Two of these patients had died as a result of fungemia, which was diagnosed by the growth of fungi in blood cultures. Of these patients, 5 had cancer, 1 was receiving chemotherapy, and 4 were terminally ill. Two patients from the intensive care unit had head injuries, and a body mass index (BMI) under 15 kg/m2, and 2 patients had type 2 diabetes mellitus. All of the patients were receiving prophylactic antimicrobial therapy. Characteristics of the patients were listed in Table 1.
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