Is alpha-hemolytic Streptococcus (Strep) on a urine culture likely a contaminant?

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From the Research

Alpha hemolytic strep in a urine culture is likely a contaminant and not a true urinary tract infection (UTI). No treatment is typically necessary for this finding alone. However, if the patient has symptoms of a UTI (such as frequent urination, burning sensation, or lower abdominal pain), consider repeating the urine culture with a clean catch midstream sample to confirm the result. Alpha hemolytic streptococci are part of the normal flora of the skin and genital area. Their presence in urine cultures often results from contamination during sample collection, rather than indicating a true infection. True UTIs are typically caused by gram-negative bacteria like E. coli, not alpha hemolytic strep. Some studies have shown that certain bacteria, such as Aerococcus urinae and Actinotignum schaalii, can be underestimated causes of UTIs 1. However, these bacteria are not typically associated with alpha hemolytic strep. The contamination rate of urine cultures can be significant, with a median institution having a contamination rate of 15.0% 2. Providing patient instruction and refrigeration of the specimen can help reduce contamination rates. In rare cases, alpha hemolytic strep can cause infections, particularly in immunocompromised patients or those with underlying medical conditions 3, 4. However, these cases are not typically associated with UTIs. If repeat culture shows the same result and the patient is symptomatic, consult with a specialist to determine if treatment is necessary. In rare cases where treatment is deemed necessary, penicillin or amoxicillin would typically be effective against alpha hemolytic strep. Always correlate laboratory findings with clinical symptoms when making treatment decisions for suspected UTIs.

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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