Etiologia e sensibilidade bacteriana em infecções do tracto urinário

AbstractIntroductionUrinary tract infections (UTI) are very prevalent in Humans immediately following respiratory infections. The main microorganisms involved have remained relatively constant over time, and their treatment, in many cases, has been done empirically, making use of antibiotics that, in principle, are supposed to have an extended-spectrum and are able to eradicate the infection.ObjectiveThe main objective of this work was to understand the behaviour of the most prevalent strains that cause urinary tract infections and assess if we can discern some trends in their resistance to antibiotics during two different time periods.Material and methodsThe retrospective study was carried out at Local Health Unit (Guarda), involving the use of 200 cultures with a positive result, for half of the year 2002 and for the rest of the year 2007. All urine samples were plated on agar CLED. The identification and their respective antibiotic were performed at VITEK 2 system (bioMérieux).ResultsThe main results suggested that the most prevalent strain in 2002 was E. coli constituting 64% of the strains identified, followed by S. marcescens with 16% and K. pneumoniae with 14%. For the year 2007, E. coli prevailed again with 66% of urinary infections, followed by P. aeruginosa with 14%. As far as the behavior of more prevalent strains towards antibiotics is concerned we found that there was an increased sensitivity of Escherichia coli compared to amoxicillin (68.8% in 2002 to 93.9% in 2007), compared to ampicillin (56.3% in 2002 to 75.8% in 2007) and to cephalothin (84.4% in 2002 to 93.9% in 2007). It only increased its resistance to trimethoprim, in 2002 it had a resistance of 18.8% and this number rose to 24.2% in 2007. Klebsiella pneumoniae has increased its capacity of resistance to amoxicillin (0% in 2002 to 75% in 2007), became completely resistant to ampicillin and reduced its sensitivity to cephalothin (85.7% in 2002 and only 25% in 2007). They also increased their resistance to pefloxacin, since in 2002 all strains were sensitive and in 2007 only 25% showed sensitivity to this antibiotic. For trimethoprim there was also a sharp increase of resistance to this bacterium: in 2002 only 28.6% of Klebsiella pneumoniae strains were resistant while in 2007 this figure rose to 75%. Klebsiella pneumoniae only increased its susceptibility to netilmicin, from a sensitivity of 85.7% in 2002 to 100% in 2007.DiscussionFrom the results we can see that Escherichia coli did not change its performance towards the antibiotics tested, even increasing its sensitivity in some cases. In relation to Klebsiella pneumoniae, there is a clear decrease in their sensitivity to most antibiotics tested.ConclusionIt is necessary to know the prevalence of the main bacteria that infect the urinary tract in order to continue empirical treatments with antibiotics