Is urine culture necessary to start antibiotic treatment for urinary tract infections? What is appropriate starting therapy?
The etiology and treatment of urinary tract infections (MVP) depends on the patient's gender, age and sexual activity, as well as the symptoms of the disease; the presence of a history of MVP infections, the conduct of a history of antibiotic therapy (for any indication); the presence of conditions that contribute to the development of the infection, its persistence or its tendency to relapse.
Asymptomatic bacteriuria is an indication for antibiotic therapy in children, pregnant women and the immunodeficient patient. Most patients who do not have clinical signs of infection do not need to be given antibiotics. Thus, this article is devoted to examining and treating patients with profit center complaints.
Bacteriuria is an indisputable indicator of MEP infection. It was traditionally believed that the detection of more than 105 uropathogens in 1 ml of urine is a sign that can differentiate a bladder infection from urinary contamination in women with pyelonephritis. Recent studies have shown that with cystitis and even pyelonephritis in women, bacteriuria at the level of 102-104 / ml can be observed [1,2,3].
Upper MEP infections (e.g. pyelonephritis), as well as infections in patients with concomitant complicating factors (e.g. structural or functional changes in MEP, previous catheterization or surgery, male) can be caused by a large number of pathogens susceptible to antimicrobials, often difficult to predict. In such cases, urine culture is recommended before the start of antibiotic therapy, in order to select the most optimal antibiotic.
In women with acute uncomplicated cystitis, the main pathogens are Escherichia coli and Staphylococcus saprophyticus, with a relatively well-known sensitivity to antibiotics. most commonly used. Many members of the Enterobacteriaceae family, which are somewhat less common in this class of individuals, are generally also susceptible to the antibiotics of choice for MVP infections. In this regard, to select a starting antibiotic, it is not necessary to carry out a microbiological examination of the urine .
Express non-cultural methods can assist in the diagnosis of PEM infections. They are particularly useful in patients suspected of cystitis, since the culture of urine in these cases is not always necessary and economically justified. Pyuria, detected using precise and rapid and inexpensive methods of quantitative urine microscopy (detection of more than 10 leukocytes in 1 μl of non-centrifuged urine) , is a fairly sensitive indicator of l infection with MEP . In the absence of microscopy, the determination of the leukocyte esterase can be used as an alternative . Microhematuria or detection of bacteria when staining non-centrifuged urine according to Gram (bacteriuria) are less sensitive indicators than pyuria, however, both methods are very specific for MVP infections . Thus, the detection of pyuria, hematuria or bacteriuria by microscopic examination of the urine in patients with symptoms of uncomplicated MEP infections, in the absence of complicating factors, indicates without no doubt an acute cystitis and does not require microbiological examination of the urine .
For patients with uncomplicated cystitis, a 3-day course of trimethoprim / sulfamethoxazole (cotrimoxazole) is an effective treatment . If there is a history of allergies to sulfa drugs or trimethoprim, as well as other contraindications to the appointment of one of these drugs, alternative antibiotics should be used. Across the world, resistance to amoxicillin (ampicillin) is increasing in pathogens of MVP infections, including community-acquired E.coli strains. In addition, short cycles of ampicillin (and other β-lactam antibiotics) may be less effective than cotrimoxazole in eradicating E. coli from the vagina, causing high relapse rate . With high efficacy, 3-day cycles of fluoroquinolones (eg ciprofloxacin) can be used . However, given the risk of reproductive resistance to this class of antibiotics, which are very important for the treatment of more severe infections, the systematic use of fluoroquinolones in cystitis should be limited. As an alternative, nitrofurantoin can be used for 7 days or once with fosfomycin trometamol . Despite reports of resistance to fosfomycin, there is no evidence of cross-resistance between fosfomycin and other classes of antibiotics. Thus, given the fact that nitrofurantoin is primarily used to treat infections of the lower parts of MVP and that fosfomycin is used (in the United States) only for uncomplicated cystitis, the emergence of resistance to nitrofurantoin or fosfomycin will not have an adverse effect on the effectiveness of antibiotic therapy for more severe infections.