What is Bacteriuria (Urinary Tract Infection)?
Bacteriuria means there are bacteria in the urine, but it can show up in two different ways: symptomatic or asymptomatic. Asymptomatic bacteriuria is when someone has bacteria in their urine but doesn’t experience any symptoms or signs of an infection. An example of this could be someone who has a long-term Foley catheter and doesn’t show any symptoms, even though they might have lots of bacteria in their urine. Symptomatic bacteriuria happens when the bacteria leads to an infection in the urinary tract, and usually, it’s a result of a single type of bacteria.
Urinary tract infections can occur in different parts of the urinary system. Lower infections can include conditions like cystitis and prostatitis, and upper infections can include pyelonephritis and pyonephrosis. Most of the time, these infections are considered “simple” or “uncomplicated.” This typically means they occur in healthy women who aren’t pregnant.
However, “complicated” urinary tract infections happen in individuals with a condition or a resistant pathogen that makes it harder for treatment to work. This could include all urinary infections in men, or in patients with an abnormal or blocked urinary tract, a weakened immune system, a catheter, or another device like a double-J stent in the urinary tract.
What Causes Bacteriuria (Urinary Tract Infection)?
The urinary tract can become contaminated or infected with bacteria in various ways. This often occurs in people over the age of 65 or those who have certain conditions like a constant urinary catheter, a bladder that can’t control urine, or a urinary opening in the abdomen. Women who have gone through menopause might be more likely to have bacteria in their urinary tract due to a change in the acidity of their vagina.
Some people can start to have bacteria in their urinary tract within 48 hours of having a urinary catheter put in. Usual bacteria and fungi that can be found include Escherichia coli, Enterococcus species, and Candida species. People who have these bacteria may not show any symptoms, but sometimes the bacteria can cause an infection that needs to be treated.
Women are more likely than men to get urinary tract infections (UTIs) due to the differences in their bodies. E. coli is the most common bacteria that causes UTIs.
Risk Factors and Frequency for Bacteriuria (Urinary Tract Infection)
Asymptomatic bacteriuria and urinary tract infections (UTIs) can occur in various groups of people. Healthy young individuals might show no symptoms despite having bacteria in their urine, but this is rare compared to older people. Women, those aged 70 and above, and people living in long-term care facilities tend to have higher rates of asymptomatic bacteriuria. The use of long-term urinary catheters and being a female diabetic also increase these rates.
- In healthy premenopausal women, about 1% to 5% may have asymptomatic bacteriuria.
- Pregnant women have a rate of 1.9% to 9.5%.
- Women and men who are at least 70 years old have rates of 10.8% to 16% and 3.6% to 19%, respectively.
- For residents in long-term care facilities, 25% to 50% of female residents and 15% to 40% of male residents might have asymptomatic bacteriuria.
- The usage of long-term urinary catheters is linked to a 100% asymptomatic bacteriuria rate.
- For diabetics, females show a higher prevalence rate of 9% to 27%, compared to males at 0.7% to 11%.
When it comes to UTIs, women are more prone to develop the condition, though men over 50 also see an increased likelihood. Half of all women will experience at least one UTI in their lifetime. For younger women, there is a 25% chance of a UTI recurrence within six months. Pregnant women who have asymptomatic bacteriuria and are untreated can have a UTI rate of around 40%. Older individuals who are not in long-term care often get UTIs, which account for a quarter of all their infections. People using long-term urinary catheters are also more at risk of UTIs. The most frequent hospital-acquired infection is catheter-associated urinary tract infections.
- Approximately 50% of women will experience at least one UTI during their lifetime.
- 1 in 3 women will develop a UTI before they turn 24.
- Within six months of the first UTI, there is a 25% chance of another UTI in younger women.
- Untreated pregnant women with asymptomatic bacteriuria may see UTI rates of up to 40%, but the typical UTI rate in pregnant women is as low as 4%.
- For elderly people not in long-term care, UTIs constitute 25% of all infections.
- People who have long-term urinary catheters are more at risk of UTIs.
- Catheter-related UTIs are the most common infection acquired in hospitals and nursing homes.
Signs and Symptoms of Bacteriuria (Urinary Tract Infection)
Lower urinary tract infections (UTIs) are generally characterized by a range of symptoms which may include frequent and urgent urination, painful urination, and lower belly pain. These symptoms are likely to appear quickly, usually within a day. It should be noted that older folks experiencing a UTI might behave in unusual ways, such as seeming confused. Of course, there could be other causes for these changes in mental state, so it shouldn’t immediately be assumed that a UTI is the culprit. A UTI can also cause more general feelings of being unwell such as energy depletion, moodiness, unease, nausea, headaches, abdominal discomfort, and back pain.
Individuals suffering from an upper UTI (which impacts the kidneys) might exhibit the symptoms associated with a lower UTI, along with high body temperature and pain in the side of the lower back. Those with a UTI may also notice some changes in their urine – it might be cloudy, darker in color, have traces of blood or emit a foul smell. However, if a person only has one of these symptoms but not the others, a UTI isn’t necessarily the cause.
Testing for Bacteriuria (Urinary Tract Infection)
If someone shows symptoms of a urinary tract infection (UTI) or has severe sepsis of unknown cause, doctors may suspect a UTI. They typically carry out a urinalysis and urine culture to confirm this. If certain values like the number of white blood cells or leukocyte esterase are high in a urinalysis, it may indicate a UTI.
If the tests suggest a UTI in a patient with symptoms and without other reasons for these results, such as frequently wearing a urinary catheter, then antibiotics should be started. In some cases, even if the urinalysis is negative, it might be appropriate to start antibiotics if the patient shows other signs of a UTI. If the sample is considered contaminated due to excess squamous cells, no antibiotics should be started until a cleaner sample can be obtained.
It is worth noting that people with a urinary catheter may show results suggesting a UTI even if they don’t have one. In these cases, actual symptoms of a UTI should be confirmed before starting treatment.
After the urine culture results come back, doctors will determine if there are enough colony-forming units (CFUs) per milliliter to suggest a UTI or if the sample might just be contaminated. Generally, over 100,000 CFUs/mL in a voided specimen could mean a UTI. However, a urinary catheter might show only 1,000 CFUs/mL and still suggest a UTI as the threshold here is much lower. If more than three organisms are seen, it typically means the sample was contaminated.
Imaging isn’t generally needed in straightforward cases, but it might be used when symptoms don’t improve after 48 to 72 hours of antibiotics, or if the patient is very ill. CT scans, with or without contrast, are commonly used. If there’s a history of kidney stones or suspicion of one, an imaging study may be considered to correctly diagnose and treat the condition.
Treatment Options for Bacteriuria (Urinary Tract Infection)
Adults who have bacteria in their urine but no symptoms, a condition known as asymptomatic bacteriuria, should generally not receive treatment unless they are pregnant, about to have a urinary procedure, or have a weakened immune system. If they have a urinary catheter and a confirmed urinary tract infection (UTI), the catheter should be removed or replaced before starting antibiotics. Several antibiotics are available to treat UTIs, including fluoroquinolones, sulfamethoxazole/trimethoprim, beta-lactams, and nitrofurantoin. The latter is only recommended for bladder infections known as cystitis.
With bacterial resistance to commonly used oral antibiotics on the rise, it’s crucial to check how susceptible the bacteria are to the chosen antibiotic. This resistance is found not only in hospital patients but also in outpatients. Certain bacteria that cause UTIs, like E. Coli and Klebsiella, are developing resistance through mechanisms that render most penicillin, cephalosporin, and monobactam antibiotics ineffective. Carbapenems are usually the chosen drugs for these resistant bacteria.
When deciding on the first-choice therapy for UTIs, healthcare providers should consider local data to determine which antibiotic is likely to work best. For bacteria such as E. Coli, Klebsiella, and Proteus, an effective antibiotic should have an 80% to 90% susceptibility rate. Any allergies the patient may have, and any recent urinary cultures should also be considered, especially if the infection is caused by bacteria resistant to multiple drugs.
As soon as the susceptibility of the bacteria is known, the antibiotic choice should be reviewed to ensure the narrowest spectrum drug is used. This ensures that only the bacteria causing the infection are targeted and minimizes the impact on other healthy bacteria. The chosen antibiotic should also be able to reach the bladder and kidneys and be capable of killing the bacteria if the patient also has a bloodstream infection. If an oral antibiotic is used, it should be easily absorbed from the gut into the bloodstream. Kidney function should be assessed when using antibiotics that require dose adjustments in patients with reduced kidney functionality.
Healthcare providers should also ensure that the duration of therapy is long enough to kill the bacteria but not so long that it causes side effects or resistance. Patients with a simple bladder infection usually take antibiotics for 3 to 7 days, depending on the type of antibiotic. For a simple kidney infection, antibiotic therapy lasts from 5 to 14 days. In the case of complex bladder and kidney infections, the treatment may last from 7 to 14 days, but this can depend on the individual case. Studies are ongoing to evaluate the effectiveness of shorter treatment durations for urinary infections.
What else can Bacteriuria (Urinary Tract Infection) be?
When trying to figure out what might be causing a urinary infection, doctors need to consider a wide range of conditions that may have similar symptoms. These might include:
- Severe kidney infection (known as acute pyelonephritis)
- Bladder cancer
- Genitourinary infections caused by Chlamydia
- Nonbacterial cystitis, an inflammation of the bladder
- Emphysematous pyelonephritis, a rare, severe kidney infection
- Emphysematous cystitis, a rare, severe bladder infection
- Interstitial cystitis, a type of chronic bladder pain syndrome
- Pelvic inflammatory disease, an infection of the organs of a woman’s reproductive system
Nailing down a diagnosis involves careful consideration of these possibilities and conducting appropriate tests to get an accurate result.
What to expect with Bacteriuria (Urinary Tract Infection)
Studies have found that women who frequently experience urinary tract infections (UTIs), even when they don’t show symptoms and receive treatment, often have a higher incidence of symptomatic UTIs and are more likely to carry bacteria resistant to antibiotics.
For most people with UTIs, the outlook is generally positive unless they develop severe sepsis, a dangerous infection throughout the body. In these severe cases, choosing the right antibiotic based on the bacteria’s susceptibility, patient’s medical history, and characteristics becomes crucial for successful treatment. It’s also important to note that every delay in starting the right antibiotic therapy can increase the risk of death. Also, unnecessary treatment should be avoided to ensure the best outcome.
