E. coli cellulitis

Virulence potential of Escherichia coli isolates from skin and soft tissue infections

Escherichia coli strains frequently are isolated from skin and soft tissue infections (SSTI); however, their virulence potential has not yet been extensively studied. In the present study, we characterized 102 E. coli SSTI strains isolated mostly from surgical and traumatic wounds, foot ulcers, and decubitus. The strains were obtained from the Institute of Microbiology and Immunology, University of Ljubljana, Slovenia. Phylogenetic backgrounds, virulence factors (VFs), and antibiotic resistance profiles were determined. Correlations between VFs and phylogenetic groups were established and analyzed with regard to patient factors. Further, the associations of the three most prevalent antibiotic resistance patterns with virulence potential were analyzed. Our results showed that the majority of the studied strains (64%) [corrected] belonged to the B2 phylogenetic group. The most prevalent VF was ompT (80%), while toxin genes cnf1 and hlyA were found with prevalences of 32 and 30%, respectively. None of the investigated bacterial characteristics were significantly associated with patient gender, age, type of infection, or immunodeficiency. The most prevalent antibiotic resistance pattern was resistance to ampicillin (46%), followed by resistance to tetracycline (25%) and fluoroquinolones (21%). Strains resistant to ciprofloxacin exhibited a significantly reduced prevalence of cnf1 (P < 0.05) and usp (P < 0.01). Our study revealed that E. coli isolates from SSTIs exhibit a remarkable virulence potential that is comparable to that of E. coli isolates from urinary tract infections and bacteremia.

Spontaneous Escherichia coli cellulitis in a child with nephrotic syndrome

Spontaneous bacterial peritonitis is the most common infectious complication of childhood nephrotic syndrome, and Streptococcus pneumoniae is the preponderant bacterial pathogen. Spontaneous bacterial cellulitis, especially of the lower extremities, is another common infection encountered in the same patient group given that chronic edema acts as a potential culture medium. Gram-positive bacteria, including streptococci and staphylococci, are the most common causes of bacterial cellulitis. We report a case of spontaneous Escherichia coli cellulitis in a patient with steroid-dependent nephrotic syndrome.

Flucloxacillin alone or combined with benzylpenicillin to treat lower limb cellulitis: a randomised controlled trial

OBJECTIVE

To determine whether using intravenous benzylpenicillin in addition to intravenous flucloxacillin would result in a more rapid clinical response in patients with lower limb cellulitis.

METHODS

This was a randomised controlled trial set in an inner city teaching hospital, comprising 81 patients with lower limb cellulitis requiring intravenous antibiotics. The main outcome measure was the mean number of doses of antibiotic required until clinical response.

RESULTS

The mean number of doses required was 8.47 (95% confidence interval (CI) 7.09 to 9.86) in the benzylpenicillin and flucloxacillin combined group. In the flucloxacillin only group it was 8.71 doses (95% CI 6.90 to 10.5), a mean difference of -0.24 doses (95% CI -2.48 to 2.01, p = 0.83). Other markers of treatment efficacy showed no difference between groups at review the following day; temperature decrease (mean difference -0.07 degrees C, 95% CI -0.76 to 0.62, p = 0.84), or diameter decrease of affected area (mean difference -34 mm, 95% CI -99 to 31, p = 0.30). Patient subjective assessments were also similar between the different drug regimen; improvement on a visual analogue scale of pain/discomfort from admission to first review (mean difference 10 mm, 95% CI -12.6 to 14.2, p = 0.91) and on second review (mean difference 15 mm, 95% CI -18.6 to 21.6, p = 0.88). Patient overall subjective feelings of improvement on first review (p = 0.32) and on second review (p = 0.64) were also similar.

CONCLUSIONS

This study provides no evidence to support the addition of intravenous benzylpenicillin to intravenous flucloxacillin in the treatment of lower limb cellulitis.

Rapidly progressive soft tissue infections

Skin and soft tissue infections are among the most common reasons for people to seek medical advice. They also represent one of the most common indications for antimicrobial therapy and account for approximately 7-10% of hospitalisations in North America. Although non-limb and non-life threatening infections may be treated on an out-patient basis with oral antibiotics, patients with more serious acute skin and soft tissue infections may require admission to hospital for management; this decision is especially true if the infection is rapidly progressive. We provide a concise overview of the differential diagnosis and approach to management of community-acquired rapidly progressive skin and soft tissue infections.