From the Guidelines
The Streptococcus urine antigen test is not a recommended or standard clinical test for diagnosing streptococcal infections, as there is no widely available or validated test for this purpose. The use of urinary antigen tests for other pathogens, such as Streptococcus pneumoniae and Legionella pneumophila, has been studied, but their impact is difficult to establish, with one interventional study showing reduced prescription of broad-spectrum antibiotics but increased risk of clinical relapse 1. For diagnosing streptococcal infections, healthcare providers typically rely on:
- Throat swabs for rapid antigen detection tests or throat cultures for Group A Strep
- Blood cultures for more invasive streptococcal infections If streptococcal infection is suspected, appropriate diagnostic testing would include a throat swab for pharyngitis or blood cultures for more serious infections. Treatment for confirmed streptococcal infections usually involves antibiotics such as penicillin, amoxicillin, or macrolides (for penicillin-allergic patients), with specific regimens depending on the type and severity of infection 1. The absence of a streptococcal urine antigen test reflects the biology of these infections, as streptococcal antigens are not typically excreted in urine in sufficient quantities to make such testing reliable for clinical diagnosis.
In terms of reducing antibiotic use, studies have shown that strategies such as invasive sampling and rapid diagnostic testing can help reduce antibiotic consumption and improve patient outcomes 1. However, the use of urinary antigen tests for streptococcal infections is not a recommended strategy due to the lack of available and validated tests.
Key points to consider when diagnosing and treating streptococcal infections include:
- The importance of prompt and accurate diagnosis to guide antibiotic therapy
- The use of throat swabs and blood cultures as primary diagnostic tools
- The selection of appropriate antibiotic regimens based on the type and severity of infection
- The need for careful consideration of antibiotic use and resistance patterns in the treatment of streptococcal infections 1.
From the Research
Strepto Urine Antigen Testing
- The Streptococcus pneumoniae urinary antigen (u-Ag) test has been used to diagnose pneumococcal infections, including community-acquired pneumonia (CAP) 2, 3, 4.
- A study published in 2020 found that u-Ag testing helped to better target antibiotic therapy and reduced mortality in COVID-19 patients with pneumococcal co-infection 2.
- Another study published in 2013 found that positive urinary antigen tests for Streptococcus pneumoniae allowed for an early switch from empiric to targeted treatment in hospitalized CAP patients, resulting in cost savings 3.
- A 2014 study found that the immunochromatographic technique for detecting pneumococcal antigen in urine had a sensitivity of 74.6% and was associated with poorer clinical outcomes in patients with bacteraemic pneumococcal pneumonia 4.
Antibiotic Treatment and Resistance
- Group A Streptococcus (GAS) has remained susceptible to penicillin and other β-lactams, but treatment failure and reduced susceptibility have been reported 5.
- A 2021 review discussed the challenges in treating GAS infections, including the mechanisms that contribute to antibiotic failure and the need for adjunctive therapeutics 5.
- Another study published in 2021 compared different antibiotic treatments for group A streptococcal pharyngitis and found that cephalosporins and macrolides may be effective alternatives to penicillin, but the evidence was uncertain 6.
Clinical Applications and Outcomes
- The use of u-Ag testing has been shown to improve patient outcomes by allowing for targeted antibiotic therapy and reducing the risk of treatment failure 2, 3, 4.
- However, the test is not without limitations, and its use should be guided by clinical judgment and laboratory results 3, 4.
- Further research is needed to fully understand the clinical applications and outcomes of u-Ag testing and to develop effective treatment strategies for GAS infections 6, 5.