ABSTRACT
Aim@#The aim of this study was to monitor the restricted water systems during the period of COVID-19 lockdown for the waterborne pathogen Legionella pneumophila. Selected water systems were monitored to evaluate the effect of stagnation in terms of Legionella colonization.@*Methodology and results@#A total of 160 water samples were taken from buildings which were temporarily shut down or had restricted usage between April-December 2020. None of the sampling points had Legionella positive history in the last three years. All water samples were tested using classic microbiological culture as the gold standard and rapid Vermicon ScanVIT Legionella test kit combined with epifluorescence microscopy. Sixteen (10%) out of 160 water samples were recorded as Legionella-positive by both methods, where none of them was positive before the COVID-19 lockdown. All positives were tested as L. pneumophila serogroup 1 with latex agglutination kit.@*Conclusion, significance and impact of study@#Colonization of Legionella in stagnant water systems occurs rapidly. Before reopening, routine monitoring in buildings is extremely important especially under restricted use or closure is in case. Flushing, disinfecting and testing are crucial for minimizing the health risks for the public health.
ABSTRACT
Objective: To evaluate effect of the morphology of simulated S-shaped root canals with Reciproc or Mtwo instruments on root canal irrigation. Methods: A total of 40 simulated S-shaped resin blocks were randomly divided into 2 groups (n=20), which was prepared by Reciproc or Mtwo. Blue ink was injected with constant speed and volume into the canals using 30G lateral opening syringe. hTe distance from needle tip to apex and vapor lock length were measured. A type of 25# 0.04 gutta-percha point was used to stir and remove the vapor lock. hTe time for removal of the vapor lock was recorded. Another syringe was used to inject saline into the canals and to measure the length of stagnant water. Results: hTe distance from needle tip to apex in the Reciproc group was signiifcantly longer than that in the Mtwo group [(4.276 ± 0.221) mm vs (3.459 ± 0.205) mm,P<0.05]. The vapor lock length in the Reciproc group was signiifcantly longer than that in the Mtwo group [(4.472 ± 0.230) mm vs (3.668±0.217) mm,P<0.05]. hTe time to remove vapor lock was signiifcantly shorter in the Reciproc group than that in the Mtwo group [(10.13 ± 1.79) s vs (15.29 ± 2.15) s,P<0.05]. The length of stagnant water was also shorter in the Reciproc group than that in the Mtwo group[(1.351 ± 0.142) mm vs (2.245 ± 0.206) mm,P<0.05]. Conclusion: hTe morphology of S-shaped root canal affects the root canal irrigation. hTe effect of root canal irrigated by Reciproc is better than that by Mtwo.