Urinary Tract Infection, UTI - Etiological agents, Source of Infection

Etiological agents, Source of infection in Urinary Tract Infection (UTI)

Etiological agents, Sources of infection in Urinary Tract Infection (UTI) are as follows:

Community-acquired

Escherichia coli is the most frequent cause of uncomplicated community-acquired Urinary Tract Infection (UTI). E. coli that cause Urinary Tract Infection (UTI) are designated Uropathogenic E. coli (UPEC) and are sufficiently different from other types of E. coli.

Other bacteria isolated from patients with Urinary Tract Infection (UTI) are Klebsiella spp, other Enterobacteriaceae, Staphylococcus saprophyticus, and Enterococcus spp. In most complicated UTIs, especially in cases of recurrent infection, Proteus, Pseudomonas, Klebsiella, and Enterobacter spp are majorly isolated.

Community-acquired Urinary Tract infections (UTI) are increasingly associated with MDR organisms. Eg: β-lactamase resistant E. coli

Hospital-acquired

Nosocomial Urinary Tract Infection (UTI) is mostly associated with microorganisms such as E. coli, Klebsiella spp, Proteus spp, Staphylococci, other Enterobacteriaceae, Pseudomonas aeruginosa, Enterococcus, and Candida spp.

About 35% of nosocomial infections are Urinary Tract infections (UTIs). Among them, 80% are due to indwelling catheters (eg. Foley catheters).

These foreign bodies once introduced into the urinary tract, especially one that remains in place for an extended period and particularly in obstruction present provide a substantial risk of Urinary Tract Infection (UTI). The infected urinary tract is the most frequent source of bacteremia.

Miscellaneous

Other less frequently isolated agents are other gram-negative bacilli such as Acinetobacter and Alealigens spp., other Pseudomonas spp., Citrobacter spp., Gardnerella vaginalis, Aerococcus urinae, and β-hemolytic Streptococci.

Bacteria such as Mycobacterium, Chlamydia trachomatis, Ureaplasma urealyticum, Campylobacter spp., Haemophilus influenza, Leptospira, and certain Corynebacterium spp. (eg: C. renale) are rarely recovered from the urine.

Renal transplant patients are immunocompromised. So, these patients not only suffer from common uropathogens but also unusual pathogens.

In the case of Salmonella spp, being isolated during the early stages of typhoid fever, it must be immediately reported to the physician. If anaerobes are suspected, the physician should perform a percutaneous bladder tap unless urine can be obtained from the upper urinary tract by another means (eg. from a nephrostomy tube).

In patients with “sterile pyuria”, gram stain may reveal unusual organisms with distinctive morphology (eg. H. influenzae, anaerobes). The presence of microorganisms in the smear that does not grow in culture is important due to the cause of infection.

Viruses and parasites are usually not considered urinary tract pathogens. Trichomonas vaginalis may occasionally be observed in urinary sediment. Schistosoma haematobium can lodge in the urinary tract and release eggs into the urine. Adenovirus types 11 and 21 have been implicated as causative agents in agents in hemorrhagic cystitis in children.