Category Archives: Microbial contaminants

Bacterial contamination of drinking water, Guadalajara, Mexico

Rubino F, Corona Y, Pérez JGJ, Smith C. Bacterial Contamination of Drinking Water in Guadalajara, Mexico. International journal of environmental research and public health.  2018 Dec 27;16(1). pii: E67. doi: 10.3390/ijerph16010067.

In many regions where drinking water supply is intermittent and unreliable, households adapt by storing water in cisterns or rooftop tanks. Both intermittent supply and stored water can be vulnerable to contamination by microorganisms with deleterious health effects. The Metropolitan Zone of Guadalajara is a rapidly growing urban center with over five million residents where household storage is nearly ubiquitous. This pilot study was conducted in July 2018 to examine the microbiological quality of drinking water in Guadalajara. Samples were tested for free available chlorine residual, total coliform bacteria, and Escherichia coli. A survey on access to water and public perspectives was also conducted. Water exiting rooftop tanks exceeded regulatory limits for total coliform levels in half of the homes studied. Piped water arriving at two homes had total coliform levels that far exceeded regulatory limits. No E. coli were detected in any of the samples. Only 35% of homes had a chlorine residual between the recommended 0.2 and 1.5 mg/L. Many homes reported unpleasant odors and colors. Only 7% of residents drank the piped water. Future studies are needed, especially during April and May when many homes reported a higher disruption to water service.

Opportunistic pathogens in drinking water treatment plants

Wang H, Xu J, Tang W, Li H, Xia S, Zhao J, Zhang W, Yang Y. Removal Efficacy of Opportunistic Pathogens and Bacterial Community Dynamics in Two Drinking Water Treatment Trains. Small. 2018 Dec 7:e1804436. doi: 10.1002/smll.201804436.

Drinking water treatment processes (DWTPs) impact pathogen colonization and microbial communities in finished water; however, their efficacies against opportunistic pathogens are not fully understood. In this study, the effects of treatment steps on the removal of Legionella spp., Legionella pneumophila, nontuberculous mycobacteria, Mycobacterium avium, and two amoeba hosts (Vermamoeba vermiformis, Acanthamoeba) are evaluated in two parallel trains of DWTPs equipped with different pretreatment units. Quantitative polymerase chain reaction analysis demonstrates significantly reduced numbers of total bacteria, Legionella, and mycobacteria during ozonation, followed by a rebound in granular activated carbon (GAC) filtration, whereas sand filtration exerts an overarching effect in removing microorganisms in both treatment trains. V. vermiformis is more prevalent in biofilm (34%) than water samples (7.7%), while Acanthamoeba is not found in the two trains of DWTPs. Illumina sequencing of bacterial 16S rRNA genes reveals significant community shifts at different treatment steps, as well as distinct bacterial community structures in water and biofilm samples in parallel units (e.g., ozonation, GAC, sand filtration) between the two trains (analysis of similarities (ANOSIM), p < 0.05), implying the potential influence of different pretreatment steps in shaping the downstream microbiome. Overall, the results provide insights to mitigation of opportunistic pathogens and engineer approaches for managing bacterial communities in DWTPs.

Bacterial contamination of drinking water and health, Egypt

Ouf SA, Yehia RS, Ouf AS, Abdul-Rahim RF. Bacterial contamination and health risks of drinking water from the municipal non-government managed water treatment plants. Environmental monitoring and assessment. 2018 Oct 29;190(11):685. doi: 10.1007/s10661-018-7054-z.

Water quality and bacterial contamination from 18 drinking water municipal plants in three locations at Giza governorate were investigated. The average total count of bacteria detected after four stages of treatments in the investigated plants was 32 CFU/1 mL compared to 2330 cfu/mL for raw water, with a reduction percentage of 98.6. Although there is a relatively high removal percent of bacterial contamination from the water sources, however, several bacterial pathogens were identified in the produced water prepared for drinking including Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, and Shigella spp. After 3 days of water incubation at 30 °C, the amount of bacterial endotoxins ranged from 77 to 137 ng/mL in the water produced from the municipal plants compared to 621-1260 ng/mL for untreated water. The main diseases reported from patients attending different clinics and hospitals during summer 2014 at the surveyed locations and assuredly due to drinking water from these plants indicated that diarrheas and gastroenteritis due to E. coli and Campylobacter jejuni constituted 65.7% of the total patients followed by bacillary dysentery or shigellosis due to Shigella spp. (7.9%) and cholera due to Vibrio cholera (7.2%). There was an increase in serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) as well as urea and creatinine values of guinea pigs consuming water produced from the non-governmental plants for 6 months indicating remarkable liver and kidney damages. Histological sections of liver and kidney from the tested animal revealed liver having ballooning degeneration of hepatocytes and distortion and fragmentation of the nuclei, while the section of the kidney showed irregularly distributed wrinkled cells, degenerated Bowman’s capsule, congested blood vessels, and inflammatory cells.

Exposure routes and health effects of microcystins

Massey IY, Yang F, Ding Z, Yang S, Guo J, Tezi C, Al-Osman M, Kamegni RB, Zeng W. Exposure Routes and Health Effects of Microcystins on Animals and Humans: A Mini-review. Toxicon. 2018 Jul 9. pii: S0041-0101(18)30306-4. doi: 10.1016/j.toxicon.2018.07.010.

Microcystins (MCs) pollution has quickly risen in infamy and has become a major problem to public health worldwide. MCs are a group of monocyclic hepatotoxic peptides, which are produced by some bloom-forming cyanobacteria in water. More than 100 different MCs variants posing a great threat to animals and humans due to their potential carcinogenicity have been reported. To reduce MCs risks, the World Health Organization has set a provisional guideline of 1 µg/L MCs in human’s drinking water. This paper provides an overview of exposure routes of MCs into the human system and health effects on different organs after MCs exposure including the liver, intestine, brain, kidney, lung, heart and reproductive system. In addition, some evidences on human poisoning and deaths associated with MCs exposure are presented. Finally, in order to protect human life against the health threats posed by MCs, this paper also suggests some directions for future research that can advance MCs control and minimize human exposure to MCs.

Transmission of Helicobacter pylori

Mladenova I, Durazzo M. Transmission of Helicobacter pylori. Minerva Gastroenterol Dietol. 2018 Feb 19. doi: 10.23736/S1121-421X.18.02480-7.

The exact modes and routes of transmission of Helicobacter pylori (H. pylori) infection remain unproven. Studies showed that H. pylori bacteria can spread directly from one person to the other, or indirectly from an infected person to the environment. Presently, interpersonal pathways are more probable than environmental exposure routes. Person to person transmission can be mainly fecal-oral or oral-oral. In the last 30 years many authors have investigated the main potential sources of H. pylori infections, vectors and risk factors for both fecal-oral and oral-oral routes of transmission, eating of contaminated food, drinking of contaminated water, and exposure to animals. They have tried to isolate H. pylori from feces, saliva, dental plaque. These aspects are the basis for the effective prevention of both H. pylori acquisition and gastroduodenal pathology associated with it. These issues will be discussed in this narrative review.

Malaria Deaths Decline in Age of Global Warming

“In the visualisations below we provide estimates of the total number of deaths from the World Health Organization (WHO) from 2000 to 2015, and the Institute of Health Metrics and Evaluation (IHME), Global Burden of Disease (GBD) from 1990 to 2016. These estimates are notably different across various countries which affects the total number of reported deaths. IHME figures, as shown below, tend to be higher; they report deaths greater than 720,000 in 2015 versus only 438,000 from the WHO.” click here

Drinking water contamination with Helicobacter pylori, Peru

Boehnke KF, Brewster RK, Sánchez BN, Valdivieso M, Bussalleu A, Guevara M, Saenz CG, Alva SO, Gil E, Xi C. An assessment of drinking water contamination with Helicobacter pylori in Lima, Peru. Helicobacter. 2018 Jan 8. doi: 10.1111/hel.12462.

BACKGROUND: Helicobacter pylori is a gut bacterium that is the primary cause of gastric cancer. H. pylori infection has been consistently associated with lack of access to sanitation and clean drinking water. In this study, we conducted time-series sampling of drinking water in Lima, Peru, to examine trends of H. pylori contamination and other water characteristics.

MATERIALS AND METHODS: Drinking water samples were collected from a single faucet in Lima’s Lince district 5 days per week from June 2015 to May 2016, and pH, temperature, free available chlorine, and conductivity were measured. Quantities of H. pylori in all water samples were measured using quantitative polymerase chain reaction. Relationships between the presence/absence and quantity of H. pylori and water characteristics in the 2015-2016 period were examined using regression methods accounting for the time-series design.

RESULTS: Forty-nine of 241 (20.3%) of drinking water samples were contaminated with H. pylori. Statistical analyses identified no associations between sampling date and the likelihood of contamination with H. pylori. Statistically significant relationships were found between lower temperatures and a lower likelihood of the presence of H. pylori (P < .05), as well as between higher pH and higher quantities of H. pylori (P < .05).

CONCLUSIONS: This study has provided evidence of the presence of H. pylori DNA in the drinking water of a single drinking water faucet in the Lince district of Lima. However, no seasonal trends were observed. Further studies are needed to determine the presence of H. pylori in other drinking water sources in other districts in Lima, as well as to determine the viability of H. pylori in these water sources. Such studies would potentially allow for better understanding and estimates of the risk of infection due to exposure to H. pylori in drinking water.