Elizabeth Hand, Pharm.D., BCPS, BCIDP
Pharmacy Residency Program Director and Clinical Assistant Professor at the UT - Austin College of Pharamacy
University Hospital System, UT - Austin College of Pharmacy
Nothing to disclose
Problem: Streptococcus anginosus group (SAG) bacteria are gram positive cocci known to colonize the human oropharynx. SAG have a propensity to cause pyogenic infections including dentoalveolar abscesses. Throughout infectious disease literature, there is a concern for bacteremia and metastatic infections following a primary SAG infection with multiple case reports of intracranial sepsis secondary to SAG bacteria. Aggressive surgical and medical management for these infections is recommended, but the optimal antibiotic management is unclear. Furthermore, we have identified a significant increase in invasive infections due to SAG at our institution over the past decade, prompting us to review the incidence, treatment, and outcomes of SAG infections originating from an oromaxillofacial source.
Materials and Methods: This is a retrospective study of all patients admitted to University Hospital between January 1, 2006 and December 31, 2017 with cultures positive for a Streptococcus anginosus group bacteria. Demographic data including age, gender, weight, comorbid conditions, and empiric antibiotic therapy were collected. The primary objective of this study was to describe the outcomes associated with SAG infections of the head and neck, including number of surgical debridements required for source control, incidence of concomitant bacteremia, in hospital and 30-day mortality, and readmission or repeat isolation of SAG from the same site within 30 days. A total of 1492 charts were screened with a documented positive culture of SAG bacteria. Of the 1492 charts, 248 patients (16.7%) were identified as having a primary head or neck infection with cultured SAG bacteria.
Results: There were an average of 18.5 cases per year (range: 8-38) between 2006 and 2017. Patients were predominantly female (n = 127, 57%) with a median age of 35 years (range: 10-87). Comorbid conditions were uncommon, with diabetes (n = 41, 18.5%) and liver disease (n = 15, 6.7%) being the most frequent. Median length of hospitalization was 5 days (range: 1-33 days). Infections were largely polymicrobial (n = 174, 78.4%) with anaerobes (n = 139, 79.9%) and methicillin-susceptible Staphylococcus aureus (n = 104; 46.8%) being the most common co-infecting pathogens. The most common empiric antibiotic therapy was ampicillin/sulbactam (n = 85, 38.3%) or clindamycin (n = 80, 36%). Definitive antibiotic therapy following culture results was given for a median of 13 total days, with 134 patients (60.4%) receiving less than 14 days. Oral antibiotics were utilized for definitive therapy in 89.2% of cases (n = 198). A small percentage of patients (n = 35, 15.8%) required more than 1 surgical debridement. Four patients (1.8%) were readmitted within 30 days for infectious complications, but only 1 patient had re-isolation of SAG from the same site. No patients had re-isolation of SAG at a distant site within 30 days post discharge.
Outcomes and Conclusion: Infections of the head and neck involving SAG are increasing at our institution. Limited data exist on the optimal management of these patients. Our study represents the largest descriptive study to date of head and neck infections in which SAG is identified. Complications were infrequent, despite the majority of patients receiving short-course oral antibiotic therapy following 1 surgical debridement. Additionally, methicillin-resistant Staphylococcus aureus and aerobic gram negative bacilli were not frequently identified, indicating broad spectrum, intravenous antimicrobial agents may be unnecessary. Our study suggests that prolonged, intravenous antibiotic therapy may not be required for SAG infections of the head and neck.
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