MICROBIOLOGY OF NONBULLOUS IMPETIGO

Our objective was to establish the aerobic and anaerobic microbiology of nonbullous impetigo (NI) in children. We used a retrospective revie w of clinical microbiology laboratory and patients' records. Specimens were obtained from 40 patients with NI lesions and showed bacterial g rowth. Aerobic or facultative anaerobic bacteria only were present In 24 patients (60%), strict anaerobic bacteria only in 5 patients (12.5% ), and mixed anaerobic-aerobic flora was present in 11 patients (27.5% ). Sixty-four isolates were recovered (1.6 per specimen): 43 aerobic o r facultative, and 21 anaerobic. The predominant aerobic and facultati ve bacteria were Staphylococcus aureus (29 isolates), Group A beta hem olytic streptococcus (GABHS) (13 isolates), and Escherichia coli (1 is olate). The predominant anaerobes were Peptostreptococcus spp. (12), p igmented Prevotella spp. (5), Fusobacterium spp. (2), and Bacteroides fragilis (1). Single bacterial isolates were recovered in 17 patients (42.5%), 13 of which were S. aureus. S. aureus alone or mixed with GAB HS or Peptostreptococcus spp. were isolated from all body sites. Mixed flora of Peptostreptococcus spp. with Prevotella spp. or Fusobacteriu m spp. was mostly found in infections of the head and neck, while E. c oli mixed with B. fragilis and Peptostreptococcus spp. were isolated f rom one infection of the buttocks area. Thirty-three organisms isolate d from 32 patients (80%) produced the enzyme beta-lactamase. This stud y demonstrates the polymicrobial aerobic-anaerobic microbiology of NI lesions.