Differences in clinical features and outcomes between group A and group G Streptococcus -induced cellulitis

Group G Streptococcal Necrotizing Soft Tissue Infection: A Pitfall of Rapid Antigen Detection Test for Group A

Background

Necrotizing soft tissue infection (NSTI) caused by group A Streptococcus (GAS) is a life-threatening disease with high morbidity and mortality. Recently, group G Streptococcus (GGS) is increasingly reported as a cause of NSTI, which shows a similar fatality rate. A rapid antigen detection test (RADT) was used for GAS-induced NSTI to assist in the immediate diagnosis when judging the need for debridement surgery.

Methods

We describe 2 NSTI cases in which an RADT for GAS was negative, and in which GGS-induced NSTI was subsequently diagnosed. Both cases involved patients over 80 years of age whose medical histories included multiple conditions, including cardiac disorder and lower leg disease. After making a 1-cm skin incision at the central part of erythema, samples for both a wound culture and an RADT for GAS were taken from the subcutaneous layer.

Results

The RADTs were negative; however, the rapidly progressing clinical courses suggested the need for immediate debridement surgeries under general anesthesia. Removal of the skin and subcutaneous tissue and an incision for drainage achieved limb salvage. Wound cultures identified Group G Streptococcus (Streptococcus dysgalactiae) without other bacteria. Negative pressure wound therapy and split-layer mesh skin graft surgery cured the severe wounds without the need for amputation.

Conclusions

Surgeons must be aware of the limitations of the RADT for GAS and determine the appropriate initial treatment based on comprehensive physical and laboratory findings.

Colonization of β-hemolytic streptococci in patients with erysipelas-a prospective study

Erysipelas is a common skin infection causing significant morbidity. At present there are no established procedures for bacteriological sampling. Here we investigate the possibility of using cultures for diagnostic purposes by determining the perianal colonization with beta-hemolytic streptococci (BHS) in patients with erysipelas. Patients with erysipelas and a control group of patients with fever without signs of skin infection were prospectively included and cultures for BHS were taken from the tonsils, the perianal area, and wounds. BHS were grouped according to Lancefield antigen, species-determined, and emm-typed. Renewed cultures were taken after four weeks from patients with erysipelas and a positive culture for BHS. 25 patients with erysipelas and 25 with fever were included. In the group with erysipelas, 11 patients (44%) were colonized with BHS, ten patients were colonized in the perianal area, and one patient in the throat. In contrast, only one patient in the control group was colonized (p = 0.005 for difference). All of the patients with erysipelas colonized with BHS had an erythema located to the lower limb. The BHS were then subjected to MALDI-TOF MS and most commonly found to be Streptococcus dysgalactiae. Renewed cultures were taken from nine of the 11 patients with BHS and three of these were still colonized. Streptococcus dysgalactiae colonizes the perianal area in a substantial proportion of patients with erysipelas. The possibility of using cultures from this area as a diagnostic method in patients with erysipelas seems promising.

Daptomycin-Based 3 Week Treatment Scheme for the First Cellulitis Episode: Low Recurrence Rate Indicative of Decreased Recurrence Propensity?

Introduction

Cellulitis recurrences are frequent, difficult to manage, and contribute considerably to overall disease burden. This retrospective cases series reports recurrence rates of first community-acquired lower limb disease episode initially treated with daptomycin.

Methods

Treatment consisted of a 21-day two substances sequential scheme: intravenous daptomycin (4 mg/kg/day) during hospitalization and roxithromycin (2 × 150 mg per os) afterwards. Primary study end-point was the rate of recurrences during follow-up; recurrence rates and their binomial 95% confidence intervals (CI) were calculated with SPSS 22.0. Recurrences were identified by (1) review of hospital records and (2) telephone questionnaires.

Results

Twenty-seven patients hospitalized for first lower limb cellulitis episodes were started on daptomycin and 26 patients completed the above three-week sequential treatment scheme. During follow-up (range 37–85 months) one recurrence occurred among the 26 patients who completed the treatment: 96.2% of these patients remained relapse free at the end of follow-up (CI 79.5–99.9%). Considering also treatment failure, the overall effectiveness of this combination treatment was 92.6% recurrence free after more than 3 years follow-up (25/27 patients; CI 75.5–99.0%). This study is limited by retrospective planning and the restricted number of included patients.

Conclusion

The choice of the treatment for the initial lower limb cellulitis episode may impact the risk of disease recurrences. Future studies should explore interventions for the first cellulitis episode as a means to modify the risk of the recurring course of this disease.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-016-0095-8) contains supplementary material, which is available to authorized users.

Etiology of Cellulitis and Clinical Prediction of Streptococcal Disease: A Prospective Study

Background.  The importance of bacteria other than group A streptococci (GAS) in different clinical presentations of cellulitis is unclear, commonly leading to treatment with broad-spectrum antibiotics. The aim of this study was to describe the etiological and clinical spectrum of cellulitis and identify clinical features predicting streptococcal etiology. Methods.  We prospectively enrolled 216 patients hospitalized with cellulitis. Clinical details were registered. Bacterial culture was performed from blood, cutaneous or subcutaneous tissue, and/or swabs from skin lesions. Paired serum samples were analyzed for anti-streptolysin O and anti-deoxyribonuclease B antibodies. Results.  Serology or blood or tissue culture confirmed β-hemolytic streptococcal (BHS) etiology in 72% (146 of 203) of cases. An additional 13% (27 of 203) of cases had probable BHS infection, indicated by penicillin response or BHS cultured from skin swabs. β-hemolytic streptococcal etiology was predominant in all clinical subgroups, including patients without sharply demarcated erythema. β-hemolytic group C or G streptococci (GCS/GGS) were more commonly isolated than GAS (36 vs 22 cases). This predominance was found in the lower extremity infections. Group C or G streptococci in swabs were associated with seropositivity just as often as GAS. Staphylococcus aureus was cultured from swabs as a single pathogen in 24 cases, 14 (64%) of which had confirmed BHS etiology. Individual BHS-associated clinical characteristics increased the likelihood of confirmed BHS disease only slightly; positive likelihood ratios did not exceed 2.1. Conclusions.  β-hemolytic streptococci were the dominating cause of cellulitis in all clinical subgroups and among cases with S aureus in cutaneous swabs. Group C or G streptococci were more frequently detected than GAS. No single clinical feature substantially increased the probability of confirmed BHS etiology.

Erysipelas, a large retrospective study of aetiology and clinical presentation

Background

Erysipelas is a common and severe infection where the aetiology and optimal management is not well-studied. Here, we investigate the clinical features, bacteriological aetiology, and treatment of erysipelas.

Methods

Episodes of erysipelas in a seven-years period in our institution were studied retrospectively using a pre-specified protocol and is presented with descriptive and comparative statistics.

Results

1142 episodes of erysipelas were identified in 981 patients. Patients had a median age of 61 years, 59 % were male, a majority had underlying diseases or predisposing conditions, and the leg was most often affected. Wound cultures were taken in 343 episodes and 56 grew group A streptococci (GAS), 53 grew group G streptococci (GGS), 11 grew group C streptococci (GCS), and 153 grew Staphylococcus aureus. Blood cultures were drawn in 49 % of episodes and 50 cultures were positive with GGS as the most common finding (21 cultures) followed by GAS in 13, group B streptococci in 5, S. aureus in 4, and GCS in 3 cultures. In 45 % of episodes, patients received antibiotics with activity against S. aureus.

Conclusions

GGS is the most common streptococcus isolated in erysipelas and the role of S. aureus in erysipelas remains elusive.