text: <unk>  species <unk>  and U. parvum) are commensal organisms commonly found in the urogenital tract of sexually active men and women. These organisms are considered to be of low virulence although several studies have demonstrated an association between vaginal colonization by<unk>  species and adverse pregnancy outcomes including perinatal morbidity and mortality. Some studies also show an association between urogenital colonization by<unk>  and nongonococcal urethritis in men. However, the pathogenic role of<unk>  in nongonococcal urethritis is still not clear. Colonization with<unk>  species occur in asymptomatic and symptomatic infants and adults, and further investigations to determine the exact pathogenic role of<unk>  is required. There is often a medical dilemma as to whether an isolation of<unk>  represents a 'true' infection or 'mere' colonization. Hence, the challenge in making a decision whether medical treatment is necessary.
option_0: Ureaplasma urealyticum
option_1: Klebsiella rhinoscleromatis
option_2: Haemophilus ducreyi
option_3: Cryptosporidium hominis
option_4: Mycobacterium chelonae
option_5: Mycobacterium xenopi
option_6: Gardnerella vaginalis
option_7: Streptobacillus moniliformis