Abstract

Background and objective: Bioindicators of drinking water are always influenced by physical and chemical factors such as turbidity and chlorine.  Considering the assessment of drinking water quality is based on residual chlorine, E.coli, heterotrophic bacteria and turbidity.  We aimed to evaluate the effect of pH, chlorine residual and turbidity on the microbial bioindicators.

Material and methods: In this descriptive-analytic study, 324 and 32 water samples were collected from rural and urban water distribution network of Aq Qala city in 2013, respectively. All steps were performed according to standard methods.

Results: In rural water supply, 5%, 9% and 33% of the samples were contaminated with fecal coliform, fecal streptococcus and the heterotrophic more than 500CFU / ml. In urban network, coliform contamination was not seen and other bioindicators were less than those of rural networks were. Turbidity of above 5 NTU in urban and rural samples was 3 and 9 percent, respectively. Bioindicators had significant relationship with residual chlorine, fecal coliform bacteria with pH and turbidity with heterotrophic bacteria (P ≤0.05).

Conclusion: The presence of fecal streptococcus bacteria in some samples without fecal coliform cannot confirm the safety of drinking water.  Microbial contamination in the presence of residual chlorine implies that just chlorination   is not enough for having healthy water.

Keywords: Chlorine, Turbidity, Biological Factors, Drinking water

ABSTRACT
             Background and objectives: Accurate diagnosis of preterm rupture of membrane (PROM) is critical during pregnancy, and researchers are seeking ways to decrease the rate of false negative results in diagnostic tests. In the present study, we compare diagnostic properties of Amnisure test and human chorionic gonadotropin (hCG) test for diagnosis of PROM.
             Methods: The study was performed on singleton pregnant women (gestational age: 20 to 41 weeks) who were referred to the Taleghani Hospital in Tehran (Iran) between December 2016 and December 2017. The study included 44 PROM patients and 44 control pregnant women. Speculum examination for cervicovaginal fluid washing, hCG test and Amnisure test were performed for all of patients.  Statistical analysis of data was performed in SPSS software package (Version 18, Chicago, IL, USA) using t-test, Chi-square test, and Mann-Whitney test. P-values less than 0.05 were considered statistically significant.
             Results: The Amnisure test had better sensitivity and specificity compared with the β-hCG test (95.5% and 97.7% vs. 93.2% and 95.5%). The Amnisure test also had higher positive and negative predictive values than the β-hCG test (97.7% and 95.5% vs. 93.3% and 94.3%). Diagnostic accuracy of the Amnisure test was also higher than that of the β-hCG test (96.6% vs. 94.3%).
             Conclusion: According to the results, the two tests have almost equal diagnostic power for detection of PROM during pregnancy.
             Keywords: Chorionic Gonadotropin, Fetal Membranes, Premature Rupture