๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
Skin flora
Skin flora
Skin is colonized by many bacteria, which may vary by anatomical location (Table 7- 6).11 Mucous membranes tend to be colonized by E. coli, Streptococcus viridans, and Peptostreptococci. Intertriginous areas are often moist and macerated, predisposing to the growth of S. aureus and Streptococci. In diabetic patients, streptococcal and coliform bacteria can be found in the perioral area, ear, perineum, and anatomical sites below the waist.
S. aureus has become increasingly important in terms of both causing severe SSIs and increasing intractability to antibiotic treatment. S. aureus is commonly found in the mucosa, including the nasal mucosa (a common colonizing location), oropharynx, and anogenital area.41 S. aureus resistance has become more common, and in severe cases may be associated with mortality rates up to 20%. While MRSA had been separated into those related to health care (HC-MRSA) and community acquired (CA-MRSA), distinctions between HC-MRSA and CA-MRSA are currently much less clinically
relevant as the evolution of the bacterial species has led to the loss of epidemiologic distinction.41 The CA-MRSA clones have been increasingly found in hospital and healthcare facilities42 leading to increased concern for healthcare providers, as these highly virulent strains can infect otherwise healthy people.43
Other skin flora include nonbacterial causes such as Candida and less common fungal species such as Cryptococcus, Aspergillus, and Mucor, particularly in the immunosuppressed and immunocompromised population. Patients with inflammatory skin conditions such as atopic dermatitis carry different bacterial strains. Prolonged antibiotic use may change local skin flora, just as vancomycin can disturb the natural gastrointestinal flora which secrete antimicrobial peptides and indirectly facilitate the colonization of opportunistic pathogens.44 Moreover, low-virulence Streptococci are a concern for infectious endocarditis, and S. aureus and S. epidermidis are a concern for prosthetic joint infections.
With the increased prevalence of antibiotic resistance exemplified by S. aureus and the slow development of new antibiotics, it is important to follow strict guidelines to prevent worsening resistance.41
Table 7-6. Bacteria Present in Normal Skin Flora in Various Anatomical Locations