Status of the effectiveness of contact lens disinfectants in Malaysia against keratitis-causing pathogens

The aim of this study was (i) to assess the antimicrobial effects of contact lens disinfecting solutions marketed in Malaysia against common bacterial eye pathogens and as well as eye parasite, Acanthamoeba castellanii, and (ii) to determine whether targeting cyst wall would improve the efficacy of contact lens disinfectants. Using ISO 14729 Stand-Alone Test for disinfecting solutions, bactericidal and amoebicidal assays of six different contact lens solutions including Oxysept®, AO SEPT PLUS, OPTI-FREE® pure moist®, Renu® fresh™,FreshKon® CLEAR and COMPLETE RevitaLens™ were performed using Manufacturers Minimum recommended disinfection time (MRDT). The efficacy of contact lens solutions was determined against keratitis- causing microbes, namely: Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, and Acanthamoeba castellanii. In addition, using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, we determined whether combination of both agents can enhance efficacy of marketed contact lens disinfectants against A. castellanii trophozoites and cysts, in vitro. The results revealed that all contact lens disinfectants tested showed potent bactericidal effects exhibiting 100% kill against all bacterial species tested. In contrast, none of the contact lens disinfectants had potent effects against Acanthamoeba cysts viability. When tested against trophozoites, two disinfectants, Oxysept Multipurpose and AO-sept Multipurpose showed partial amoebicidal effects. Using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, the findings revealed that combination of both agents in contact lens disinfectants abolished viability of A. castellanii cysts and trophozoites. Given the inefficacy of contact lens disinfectants tested in this study, these findings present a significant concern to public health. These findings revealed that targeting cyst wall by using cyst wall degrading molecules in contact lens disinfecting solutions will enhance their efficacy against this devastating eye infection

Resistance of Acanthamoeba castellanii cysts to physical, chemical, and radiological conditions

Resistance of Acanthamoeba castellanii cysts to disinfection agents, antimicrobial agents, heat, freeze-thawing, ultraviolet radiation (UV), gamma irradiation, and cellulase were evaluated in vitro. Following exposure to different agents, the cysts were removed and cultured for A. castellanii trophozoites for 3-14 days. Solutions containing 20% isopropyl alcohol or 10% formalin effectively killed A. castellanii cysts. Hydrogen peroxide (3%, AOSept Disinfectant) effectively killed A. castellanii cysts after 4 hr of exposure. Polyhexamethylene biguanide (0.02%), clotrimazole (0.1%), or propamidine isethionate (Brolene) were effective in killing A. castellanii cysts in vitro. Acanthamoeba castellanii cysts were resistant to both 250 K rads of gamma irradiation and 800 mJ/cm(2) Of UV irradiation. Excystment of trophozoites was accelerated after exposure to 10, 100, and, 1,000 units of cellulase. These results suggest that A. castellanii cysts benefit by enhanced survival because of their resistance to very harsh environmental conditions

Serologic response to Epstein-Barr virus antigens in patients with systemic lupus erythematosus: a controlled study

Previous studies showed a link between systemic lupus erythematosus (SLE) and Epstein-Barr virus (EBV) infection. We sought to determine the features of serologic response to EBV in SLE patients and whether this response differs from those of systemic sclerosis (SSc) and primary antiphospholipid syndrome (PAPS) patients as well as healthy individuals. Sera from 198 consecutive SLE patients have been tested to detect IgG antibodies to EA/D, EBNA-1, VCA P18 and for comparison, cytomegalovirus (CMV) using commercially available ELISA kits (Trinity Biotech, USA). Forty-six SSc patients and 38 PAPS patients were enrolled as diseased control groups and sixty-five individuals as healthy controls. Significantly more SLE (54%, P = 0.001, OR 5.77, 95% CI 2.8-11.6), SSc (41.3%, P = 0.005, OR 3.4, 95% CI 1.4-8.2) and PAPS sera (36.8%, P = 0.023, OR 2.86, 95% CI 1.14-7.22) reacted against EA/D than healthy controls (16.9%). The mean age of anti-EA/D-positive SLE patients was significantly higher, and their disease duration was longer compared to anti-EA/D-negative SLE patients (41 +/- 14 vs. 33.8 +/- 10.8 years, P < 0.001 and 100 +/- 73 vs. 71 +/- 62 months, P = 0.003). In SLE patients, EA/D reactivity was associated with Raynaud's phenomenon and the presence of any anti-ENA antibodies. Although it did not reach a statistical significance, anti-EBNA-1 reactivity was slightly lower in patients with SLE. The frequency of anti-CMV Ig G positivity was found significantly higher in SLE patients (100%) when compared to patients with SSc (95.7%), PAPS (94.7%) and healthy controls (95.4%) (P = 0.035, P = 0.025 and P = 0.015 respectively). Our results support the proposed link between EBV and SLE. The finding that SSc and PAPS patients also have increased frequency of anti-EA/D response has revealed that this immune interaction may not be unique to patients with SLE, and there may be a common mechanism involving EBV in these autoimmune diseases

HEPATITIS C TESTING AMONG ADULTS BORN BETWEEN 1945 AND 1965 IN TURKEY: A MULTICENTRE STUDY

Conclusions: We determined that the anti-HCV seropositivity rate is significantly higher in adults born between 1945-1965 compared to the younger adults as indicated in the literature. According to data from this study together with the WHO and CDC suggestions, we believe that it is appropriate to offer anti-HCV serology testing for people over 50 years of age since the anti- HCV seroprevalence in this age group is relatively high