PurposeAcanthamoeba keratitis (AK) is a painful and potentially blinding corneal infection caused by Acanthamoeba spp. In Madrid, environmental studies have demonstrated a high presence of these free-living amoebae in tap water. Since most of AK cases occur in contact lenses (CL) wearers with inadequate hygiene habits, the presence of Acanthamoeba in discarded CL has been studied and compared with other common etiological agents of keratitis, such as Pseudomonas aeruginosa and Staphylococcus aureus.MethodsOne hundred and seventy-seven healthy individuals from Madrid contributed their discarded CL and answered a questionnaire on hygiene habits. DNA was extracted from the CL solution and analyzed by real-time PCR for Acanthamoeba, Pseudomonas aeruginosa and Staphylococcus aureus. These CL and their solutions were also cultured on non-nutrient agar to isolate Acanthamoeba.ResultsAmong the 177 samples, Acanthamoeba DNA was detected in 87 (49.2%), P. aeruginosa DNA in 14 (7.9%) and S. aureus DNA in 19 (10.7%). Cultivable amoebae, however, were observed in only one sample (0.6%). This isolate was genotyped as T4. The habits reported by this CL owner included some recognized risk factors for AK, but in this study only the practice of “not cleaning the CL case” presented some statistical significant association with Acanthamoeba DNA presence. Detection of the investigated bacterial DNA did not demonstrate statistical significant association with the studied practices, but the presence of P. aeruginosa revealed a possible inhibition of Acanthamoeba in these samples.ConclusionsThe PCR results suggest a high presence of Acanthamoeba spp. in healthy CL wearers from Madrid, but we can assume that CL solutions are properly disinfecting the CL since only 1.1% of the positive PCR samples correspond to viable amoebae and, after four years, only one participant reported stronger ocular problems. Nevertheless, more studies are necessary to corroborate this hypothesis.

Microsporidia are opportunistic intracellular parasites, generating serious pathology in individuals with a compromised immune system. Infection by microsporidia inhibits p53 and Caspase 3, proteins involved in apoptosis and the cell cycle, which are vital in the malignant process of epithelial cells. The presence of microsporidia in the intestinal tissues of 87 colon cancer (CC) patients and 25 healthy controls was analyzed by real-time PCR and an immunofluorescence antibody test. Anti-Encephalitozoon antibodies were analyzed in serum samples by ELISA (enzyme linked immunosorbent assay). In 36 (41.3%) CC cases, microsporidia infections were identified in their tissues vs. no cases among control subjects (p < 0.0001). An increase in IgG and IgE anti-Encephalitozoon antibodies was found in patients with CC, which would demonstrate continuous and previous contact with the parasite. The high prevalence of microsporidia in tissues and the seroprevalence in patients with CC suggest a relationship between microsporidia and the etiopathogenesis of CC.