From the Guidelines
The recommended treatment for a urinary tract infection (UTI) caused by Methicillin-Sensitive Staphylococcus aureus (MSSA) typically involves beta-lactam antibiotics, with first-line therapy consisting of oral cephalexin 500 mg four times daily for 7-14 days, depending on infection severity. When considering the treatment for MSSA UTI, it's essential to note that the microbial spectrum is greater than for uncomplicated UTIs, and antimicrobial resistance is more likely 1. The European Association of Urology guidelines on urological infections emphasize the importance of appropriate management of the urological abnormality or the underlying complicating factor, as well as optimal antimicrobial therapy based on the severity of the illness, local resistance patterns, and specific host factors 1. Key factors to consider in the treatment of complicated UTIs include:
- Obstruction at any site in the urinary tract
- Urinary tract infection in males
- Pregnancy
- Diabetes mellitus
- Immunosuppression
- Recent history of instrumentation
- Health care–associated infections
- Multidrug-resistant organisms isolated Treatment duration should be closely related to the treatment of the underlying abnormality, and a urine culture and susceptibility testing should be performed to guide the choice of antimicrobial agent 1. In general, treatment for 7 d to 14 d is recommended, but the duration may be shorter (e.g., 7 d) in cases where short-course treatment is desirable due to relative contraindications to the antibiotic administered 1. Alternative options for MSSA UTI treatment include dicloxacillin 500 mg four times daily or amoxicillin-clavulanate 875/125 mg twice daily, and for more severe infections requiring hospitalization, intravenous options such as cefazolin 1-2 g every 8 hours or nafcillin 1-2 g every 4-6 hours may be effective 1.
From the Research
Treatment of MSSA Urinary Tract Infections
- The recommended treatment for urinary tract infections (UTIs) caused by Methicillin-Sensitive Staphylococcus aureus (MSSA) is not explicitly stated in the provided studies, as they primarily focus on bloodstream infections, MRSA infections, or the effects of human urine on MRSA virulence.
- However, based on the study 2, penicillinase-resistant penicillins (flucloxacillin, dicloxacillin) are the antibiotics of choice for the management of serious MSSA infections.
- First-generation cephalosporins (cefazolin, cephalothin, and cephalexin) may also be used for less serious MSSA infections, such as skin and soft tissue infections, or in patients with penicillin hypersensitivity 2.
- It is essential to note that the treatment of MSSA UTIs may require a different approach than the treatment of other types of MSSA infections, and the choice of antibiotic should be guided by the severity of the infection, patient factors, and local resistance patterns.
Considerations for MSSA UTI Treatment
- The study 3 highlights the importance of optimal early antibiotic therapy in the treatment of MSSA bloodstream infections, which may also be relevant for the treatment of MSSA UTIs.
- The study 4 reports a case of MRSA UTI that progressed to meningitis, emphasizing the potential severity of Staphylococcus aureus infections in the urinary tract.
- The studies 5 and 6 provide insights into the effects of human urine on MRSA virulence and the role of copper resistance in MRSA fitness during UTI, which may have implications for the development of novel therapeutic strategies for MSSA UTIs.