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From the Research
Common Bacteria Found in Urine
- Escherichia coli (E. coli) is the most predominant pathogen causing 80-90% of community-acquired UTIs and 30-50% of nosocomially-acquired UTIs 1
- Staphylococcus saprophyticus, Enterococcus faecalis, and Streptococcus agalactiae are also common Gram-positive uropathogens 2
- Other bacteria such as Aerococcus, Corynebacterium, Actinobaculum, and Gardnerella can also cause UTIs, although they are less common 2
- Uncultivated bacteria are also present in the adult female bladder, and their presence is widespread among women 3
Bacterial Characteristics
- Phylogenetic group B2 is the most predominant group among primary infecting E. coli, and is associated with susceptibility to many antimicrobials 1
- Phylogenetic group A is associated with resistance to many antimicrobials and multidrug resistant (MDR) strains 1
- Biofilm formation capacity is higher in primary infecting E. coli that cause persistence or relapse of UTI 1
- Certain virulence factor genes (VFGs) such as adhesins, iron-uptake systems, and toxins are associated with persistence or relapse of UTI 1
Urine Culture and Diagnosis
- A urine culture with ≥ 10(5) CFU/ml is classically considered as positive, although lower counts are valued in certain clinical settings 4
- The development of antimicrobial resistance affects uropathogens, mainly E. coli, which remains the most frequently isolated in urine cultures 4
- Factors related to urine culture count, such as methods to obtain urine, conservation of the sample, or use of chemical preservatives, are critical points to be discussed in detail 4