As one of the earliest developed antimicrobial classes, sulfonamides remain important therapeutic options for the empiric and definitive treatment of various infectious diseases. In the general population, approximately 3–8% of patients are reported to experience a sulfonamide allergy. Sulfonamide allergies can result in various physical manifestations; however, rash is reported as the most frequently observed. In patients with human immunodeficiency virus (HIV), dermatologic reactions to sulfonamide antimicrobial agents occur 10 to 20 times more frequently compared to immunocompetent patients. This article describes the incidence, manifestations, and risk factors associated with sulfonamide allergies. The potential for cross-reactivity of allergies to sulfonamide antimicrobials with nonantimicrobial sulfonamide medications is also reviewed. Data suggest that substitutions at the N1 and N4 positions are the primary determinants of drug allergy instead of the common sulfonamide moiety. For patients with an indication for a sulfonamide antimicrobial with a listed allergy, it is important for healthcare practitioners to adequately assess the allergic reaction to determine appropriate management. Rechallenge and desensitization strategies may be appropriate for patients with delayed maculopapular eruptions, while alternative treatment options may be prudent for more severe reactions. Available data suggests a low risk of cross-allergenicity between sulfonamide antimicrobial and nonantimicrobial agents.

Background Vancomycin-resistant enterococci are an important cause of healthcare-associated infections and are inherently resistant to many commonly used antibiotics. Linezolid is the only drug currently approved by the US Food and Drug Administration to treat vancomycin-resistant enterococci; however, resistance to this antibiotic appears to be increasing. Although outbreaks of linezolid- and vancomycin-resistant Enterococcus faecium (LR-VRE) in solid organ transplant recipients remain uncommon, they represent a major challenge for infection control and hospital epidemiology. Methods We describe a cluster of 4 LR-VRE infections among a group of liver and multivisceral transplant recipients in a single intensive care unit. Failure of treatment with linezolid in 2 cases led to a review of standard clinical laboratory methods for susceptibility determination. Testing by alternative methods including whole genome sequencing (WGS) and a comprehensive outbreak investigation including sampling of staff members and surfaces was performed. Results Review of laboratory testing methods revealed a limitation in the VITEK 2 system with regard to reporting resistance to linezolid. Linezolid resistance in all cases was confirmed by E-test method. The use of WGS identified a resistant subpopulation with the G2376C mutation in the 23S ribosomal RNA. Sampling of staff members’ dominant hands as well as sampling of surfaces in the unit identified no contaminated sources for transmission. Conclusions This cluster of LR-VRE in transplant recipients highlights the possible shortcomings of standard microbiology laboratory methods and underscores the importance of WGS to identify resistance mechanisms that can inform patient care, as well as infection control and antibiotic stewardship measures.

Background: Antibiotics are commonly prescribed for uncomplicated urinary tract infection (UTI) and acute otitis media (AOM) and may be unnecessary at times. The aim of this study was to evaluate prescribing practices for UTIs and AOM in a rural ambulatory care setting and to identify areas for improvement. Methods: In a single-center, retrospective review conducted at a rural clinic, patients diagnosed with uncomplicated UTI and AOM were included. Patients were identified by International Classification of Diseases, Tenth (ICD-10) codes, and data were collected for visits between January 1, 2017, and December 31, 2017. The primary outcome was to assess adherence of antimicrobial prescribing to current treatment guidelines. Results: Of the 76 patients identified, 28 met inclusion criteria. Of the 28 patients, 75% received an agent recommended first line in the treatment guidelines, and 18 of the 21 received a recommended dose. Only 17% of patients were prescribed an appropriate duration of treatment. Conclusion: Opportunities exist for antimicrobial stewardship interventions for uncomplicated UTIs and AOM. Prescribers are not consistently adhering to guidelines in regard to antibiotic choice, dose, or duration. Additional education and stewardship interventions are crucial considering the increased prevalence of antimicrobial resistance.