What is the appropriate treatment for a patient with a urine culture positive for Beta-hemolytic Streptococcus, group B, with 25,000-50,000 colony forming units per milliliter (CFU/mL), despite a negative urinalysis?

From the Guidelines

The patient's urine culture showing Beta hemolytic Streptococcus group B at 25,000-50,000 colony forming units per mL requires treatment with penicillin or ampicillin as first-line therapy, despite a negative urinalysis. This represents a significant bacterial growth that necessitates antibiotic treatment to prevent potential complications. The most recent and highest quality study 1 provides guidelines for the management of asymptomatic bacteriuria, but it does not directly address the treatment of Beta hemolytic Streptococcus group B infections. However, based on the provided evidence, penicillin or ampicillin are the recommended treatments for Beta hemolytic streptococcal infections. For adults, a typical regimen would be amoxicillin 500mg three times daily for 5-7 days, or penicillin V 500mg four times daily for 5-7 days. For patients with penicillin allergy, alternatives include cephalexin 500mg four times daily or nitrofurantoin 100mg twice daily for 5-7 days. It's essential to note that the negative urinalysis does not rule out the presence of a significant bacterial infection, as the culture results take precedence. Complete treatment is necessary to prevent complications like pyelonephritis or systemic infection. The guidelines for the prevention of perinatal group B streptococcal disease 1 also support the use of penicillin or ampicillin as first-line therapy for GBS infections. Therefore, treatment with penicillin or ampicillin should be initiated promptly to ensure the best possible outcome for the patient.

From the FDA Drug Label

In cases of β-hemolytic streptococcal infections, treatment should continue for at least 10 days. The patient has a urine culture showing Beta hemolytic Streptococcus, group B with 25,000-50,000 colony forming units per mL. The drug of choice for treatment of beta-hemolytic streptococcal infections is penicillin and ampicillin. However, clindamycin can be used as an alternative in clinically appropriate circumstances. The recommended treatment duration for β-hemolytic streptococcal infections with clindamycin is at least 10 days 2. Penicillin therapy must be sufficient to eliminate the organism, with a ten-day minimum 3.

From the Research

Urine Culture Results

• The patient's urine culture result shows Beta hemolytic Streptococcus, group B with 25,000-50,000 colony forming units per mL 4.
• The presence of group B streptococci in urine cultures from males and non-pregnant females can be significant, with 1% of 24,000 urine cultures found to harbor group B streptococci in quantities greater than or equal to 10^5 colony forming units (cfu)/ml 4.

Antibiotic Resistance Patterns

• Penicillin and ampicillin are drugs of choice for treatment of beta-hemolytic streptococcal infections 5, 6.
• However, some studies have reported resistance to penicillin and ampicillin, with 15% of clinical isolates exhibiting intermediate or decreased sensitivity to penicillin, and 17% to ampicillin 6.
• All isolates were sensitive to vancomycin, ofloxacin, ampicillin, ciprofloxacin, nitrofurantoin, and penicillin, but resistance was noted to other antibiotics such as azithromycin, ceftriaxone, clindamycin, cefazolin, and cefamandole 6.

Treatment Options

• For patients with group B streptococcal bacteriuria, treatment with nitrofurantoin may be considered 6.
• The choice of antibiotic for intrapartum chemoprophylaxis should be guided by the organism's antibiotic sensitivity pattern, especially in women allergic to penicillin and colonized with group B streptococci 6.