Atypical pathogens in urinary tract infections: a systematic review

Abstract

Urinary tract infection [UTI] accounts for a significant portion of the worldwide infections, whose cause occurs predominantly through Gram-negative bacilli, followed by Gram-positive bacteria and fungi. However, a number of cases by atypical pathogens are increasing. Thus, a systematic review was carried out on UTIs caused by atypical/emerging agents, covering etiological, epidemiological, clinical and therapeutic aspects. The search conducted via PubMed database and 59 articles composed the final sample. The laboratory approaches reported have included uroculture with special media; molecular methods such as PCR, real-time PCR, and nucleic acid sequencing; and MALDI-TOF mass spectrometry. Pathogens found among bacteria, including Gram-negative bacilli, Gram-positive cocci, diphtheroids, Mycoplasmataceae members, actinomycetes, and Gram-variable coccobacilli; yeasts, molds and microsporidia; virus, including BK polyomavirus, HPV, CMV and HSV-2; and a protozoan, Trichomonas vaginalis. The risk factors appear to be associated with patients' intrinsic features, such as advanced age, female gender, chronic diseases, prostatic hyperplasia, immunocompromised, genitourinary tract alteration; or risky situations as long-term urinary catheter usage, urinary tract manipulation, cancer chemotherapy, alcoholism, prolonged use of antibiotics and risky sexual behavior. The difficulty in identifying these agents was also evident, due to their peculiar characteristics or the unavailability of more sophisticated methods in the laboratorial routines, which implicates in the clinical management. Therefore, it is important that the medical and the microbiology teams are aware of the possibility of these agents in order to assess the need for further testing. The importance of antimicrobial susceptibility tests is also emphasized because of these organisms’ different profiles.