Biochemical and microbiological diagnosis

Abstract

Urinary tract infections (UTIs) occur when bacteria and fungi colonize the urethra and ascend to the bladder and kidney, by generating an infection. Biochemical and microbiological studies are required to confirm the diagnosis and the infectious etiology that will lead to the antimicrobial therapy. There are different stages to study urine: sample taking, cooling and processing along with the physical-chemical study and urine culture identifying the causing organism and quantifying the number of bacteria per milliliter expressed as colony forming units/ml (CFU/ml). To differentiate infection from contamination in asymptomatic patients, bacterial growth should be ≥10⁵ CFU/ml. Streptococcus group B should be routinely searched in pregnant women and in people with diabetes, the most frequent are Escherichia coli. and enterobacteria. The presence of Candida should be considered in hospitalized patients, with urinary catheters, patients with diabetics, patients with neoplasms, history of broad-spectrum antibiotic drugs, steroids, urological procedures or fungal vaginitis. The antibiogram allows knowing the sensitivity of a germ before exposure with an antibiotic.