From the Guidelines
The most common bacteria causing UTIs are Escherichia coli, accounting for approximately 75% of recurrent UTIs, followed by Enterococcus faecalis, Proteus mirabilis, Klebsiella, and Staphylococcus saprophyticus.
Bacterial Causes of UTIs
The bacteria that cause UTIs typically originate from the periurethral area and ascend to the urinary tract, causing infection [ 1 ]. The most common organisms responsible for UTIs include:
- Escherichia coli (E. coli)
- Enterococcus faecalis
- Proteus mirabilis
- Klebsiella
- Staphylococcus saprophyticus These bacteria are usually found in the bowel flora and can colonize the urinary tract, leading to infection [ 1 ]. It's essential to note that the specific bacteria causing UTIs can vary depending on the patient's underlying risk factors and medical conditions.
Patient Risk Factors
Certain patient populations, such as postmenopausal women with atrophic vaginitis, are at increased risk for recurrent UTIs [ 1 ]. Additionally, patients with underlying structural or medical problems, such as urinary tract obstruction, diabetes, or immunosuppression, are more likely to develop complicated UTIs with less common bacterial species [ 1 ].
Clinical Considerations
When evaluating patients with UTIs, it's crucial to consider their individual risk factors and medical history to guide diagnosis and treatment [ 1 ]. In most cases, UTIs can be treated empirically with antimicrobial therapy, but recurrent or complicated infections may require further evaluation and imaging studies to detect underlying anatomical abnormalities or persistent infection [ 1 ].
From the Research
Bacteria that Cause UTIs
- The most common bacterium implicated in UTI is uropathogenic Escherichia coli 2
- Other bacteria that can cause UTIs include:
- Yeast such as Candida species can also cause UTIs 2
Prevalence of Bacteria in UTIs
- E. coli is the predominant uropathogenic organism, accounting for 67.1% of UTI cases in one study 5
- Klebsiella pneumoniae accounts for around 10% of UTI cases 5
- Proteus mirabilis accounts for around 3.7% of UTI cases 5
- The prevalence of UTI-causing bacteria can vary depending on the population and location 3, 5