Staphylococcus aureus is the most common bacterial agent of the skin flora of patients with seborrheic dermatitis

Background Seborrheic dermatitis is an inflammatory skin disease that affects 1–3% of the general population. The Malassezia species has been implicated as the main causative agent; however, the bacterial flora of the skin may also play role in the etiopathogenesis. Therefore, we investigated the most common bacterial agent of the skin flora of patients with seborrheic dermatitis. Materials and Methods Fifty-one patients with seborrheic dermatitis and 50 healthy individuals are included in this study. Sterile cotton swabs were rubbed on the scalp of the participants for bacterial culture. Colonial morphology was identified with gram stain and catalase test. Results Staphylococcus aureus was isolated from 25 (49%) patients with seborrheic dermatitis and 10 (20%) healthy individuals within the control group. Coagulase-negative staphylococci were isolated from 24 (47.1%) patients with seborrheic dermatitis and 17 (34%) healthy individuals within the control group. Diphtheroids were present in 2 (3.9%) patients and 1 (2%) subject within the control group. Gram-negative bacilli were present only in 1 (2%) patient. Hemolytic streptococci and bacilli were identified in 1 (2%) subject from each group. Colonization of coagulase-negative staphylococci, diphtheroids, gram-negative bacilli, hemolytic streptococci, and bacillus did not differ between patients and healthy controls. However, S. aureus colonization was significantly more common in patients with seborrheic dermatitis than in healthy controls. Conclusion Within this study we revealed that S. aureus colonization was significantly higher among the patients. Therefore, we propose that, in addition to the Malassezia species, S. aureus may play a role in the etiopathogenesis of seborrheic dermatitis.

gram-positive cocci that produced yellow pigmentation on mannitol-salt agar were described as S. aureus.
Statistical analysis was performed using SPSS 22.0 (SPSS Inc., Chicago, IL). Continuous variables were defined as the mean (±) standard deviation and medians (minimum-maximum). Categorical variables were expressed as percentages.
Differences between groups were analyzed by Independent Samples t test for numerical variables and chi-square test for categorical variables. A p-value <0.05 was considered statistically significant.

Results
Fifty-one patients with seborrheic dermatitis (28 female, 23 male) and 50 healthy individuals within the control group (30 female, 20 male) were included in the study (p=0.60

Introduction
Seborrheic dermatitis is a chronic inflammatory skin disease that affects 1-3% of the general population [1]. Seborrheic dermatitis is more common in men than in women and usually occurs in adolescents and young adults. Seborrheic dermatitis presents with erythematous, yellowish, greasy, scaly plaques. The lesions predominantly occur on sebaceous gland-rich areas like scalp, eyebrows, ears, nasolabial folds, chest, axillae, and groin [1]. The diagnosis of seborrheic dermatitis is usually made on the basis of its clinical features.
The etiology remains unknown; however, Malassezia yeasts, skin sebum levels, androgens, and immunologic mechanisms have been described as contributing factors [2]. Overgrowth of Malassezia species has been found to be associated with inflammation in seborrheic dermatitis. However, similar amounts of Malassezia species have also been reported in patients with seborrheic dermatitis and control groups [2,3].
Nevertheless, bacterial skin microbiota has been implicated in the pathogenic process of seborrheic dermatitis [4]. Propionibacterium acnes and micrococci like Micrococcus butyricus, Micrococcus pyogenes var. aureus have been considered as possible etiologic agents [5]. However, the association of bacteria with seborrheic dermatitis remains controversial [4]. Therefore, in this study, we aim to investigate the most common bacterial agent of the skin flora in patients with seborrheic dermatitis.

Materials and Methods
This study included 51 patients with seborrheic dermatitis of the scalp and 50 healthy individuals within the control group who were admitted to the dermatology outpatient clinic between February and April 2016. All participants provided written informed consent. The exclusion criteria were having an inflammatory skin disease like psoriasis or lichen planus and receiving any topical or systemic treatment for seborrheic dermatitis. The scoring index that was described by Koca et al was used to determine the severity of seborrheic dermatitis [6]. We evaluated the presence of erythema, desquamation, pruritus and irritation as absent (0), mild (1), moderate (2) and severe (3)  The prevalence of seborrheic dermatitis in patients with

Discussion
The etiopathogenesis of seborrheic dermatitis is not clearly understood. However, Malassezia species has been implicated as the main causative agent in seborrheic dermatitis [7]. In    burning, and pain were caused by bacterial community [14].
In our study, S. aureus and coagulase-negative staphylococcus were the most common bacteria isolated from the patient and control groups, respectively. S. aureus colonization was significantly more frequent in the skin lesions of patients with seborrheic dermatitis (49%) than in healthy subjects within the control group (20%). There was no clinical sign and symptom of any bacterial infection in the lesions of the patients with seborrheic dermatitis. In addition, coagulase-negative Staphylococcus was more com-