A urinary tract infection (UTI) is a common condition typically caused by Escherichia coli (E. coli). However, Group B Streptococcus (GBS), also known as Streptococcus agalactiae, can sometimes be the cause. While GBS is widely recognized for its potential risk to newborns, it is also a uropathogen that causes UTIs in adults. GBS UTIs present with familiar symptoms but require specific identification and a tailored antibiotic regimen. Treating this infection correctly is important to ensure the bacteria are fully cleared and to prevent potential complications.
What is Group B Strep UTI?
Group B Streptococcus frequently lives in the gastrointestinal and genitourinary tracts of many healthy individuals without causing illness. This presence without symptoms is called colonization, and 20% to 40% of adults normally carry GBS. The bacteria only become a problem when they move into the urinary system and multiply, leading to an active infection. This transition from harmless colonization to a symptomatic infection is how a GBS UTI develops.
Once an infection takes hold, the symptoms are often indistinguishable from a UTI caused by E. coli. Common signs include dysuria (painful or burning urination), increased frequency, and urgency to urinate. Some people may also experience pressure in the lower abdomen or blood in the urine, indicating bladder inflammation. Individuals with underlying conditions, such as diabetes or obesity, as well as older adults, are at a higher risk for GBS UTIs.
How Healthcare Providers Diagnose GBS UTIs
Classic UTI symptoms are not sufficient to determine the specific bacterial cause, making laboratory confirmation essential for a GBS UTI. Healthcare providers request a clean-catch urine sample, which is sent for a urine culture and sensitivity testing (C&S). The culture process allows the laboratory to grow and isolate the bacteria, which is the only way to positively identify Streptococcus agalactiae as the infectious agent.
The C&S test is particularly important because it reveals the specific antibiotics that will be effective against the identified GBS strain. This susceptibility profile is necessary to guide treatment, as GBS can be naturally resistant to certain antibiotics used for other UTIs. A diagnosis of a true GBS UTI is confirmed when a significant colony count of the bacteria (typically 10,000 colony-forming units per milliliter of urine or more) is found alongside a patient’s symptoms. This diagnostic step ensures the prescribed treatment is specifically targeted at the organism causing the illness.
The Treatment Protocol for GBS Infections
Once a GBS UTI is confirmed by culture, the treatment focuses on administering appropriate antibiotics to eradicate the bacteria. The preferred first-line treatment is a class of antibiotics known as beta-lactams, specifically penicillins like ampicillin or amoxicillin. These agents are highly effective because GBS is generally sensitive to them, allowing for a targeted attack on the bacterial cell wall. A standard treatment course for an uncomplicated GBS UTI typically lasts between 7 and 10 days, though the exact duration may vary based on the infection’s severity.
For individuals who have an allergy to penicillin, alternative antibiotics are available, but their selection must be carefully guided by the C&S testing. Cephalosporins, such as cephalexin, are often used if the allergy is not severe. If a patient has a severe penicillin allergy, other options like nitrofurantoin or vancomycin may be considered, depending on the susceptibility results. The choice of an alternative medication is important because GBS strains show increasing resistance to certain other drug classes, including erythromycin and clindamycin.
It is important to complete the entire course of the prescribed antibiotic, even if symptoms begin to clear up quickly. Stopping medication prematurely can allow the most resistant bacteria to survive, potentially leading to a relapse or a harder-to-treat infection. Following the conclusion of the antibiotic regimen, a healthcare provider may recommend a follow-up urine culture, known as a “test of cure.” This test confirms that the bacteria have been completely eliminated from the urinary tract, especially in pregnant individuals or those with complicated infections.
Reducing the Likelihood of Recurrence
After an acute GBS UTI is treated, implementing preventative measures is an important part of long-term urinary tract health. Maintaining a high fluid intake by drinking plenty of water helps to flush bacteria out of the urinary system regularly. This simple action reduces the concentration of bacteria in the bladder and minimizes the chance of colonization turning into an active infection.
Careful hygiene practices are a fundamental preventative step, particularly wiping from front to back after using the toilet. This helps prevent the transfer of GBS bacteria from the gastrointestinal area to the urethra, a common route for infection. Urinating immediately after sexual intercourse can also help wash away any bacteria that may have entered the urethra.
For postmenopausal women, local estrogen replacement therapy can be helpful because it supports the natural health and microbial balance of the genitourinary tissue. Individuals with chronic health issues, such as diabetes, should focus on managing their underlying condition, as high blood sugar levels can increase the risk of recurrent infections. If non-antimicrobial interventions are not sufficient, a healthcare provider may discuss continuous or postcoital low-dose antibiotic prophylaxis to further reduce the frequency of recurrent UTIs.