Blooms of cyanobacteria have been documented throughout history, all over the world. Mass populations of these organisms typically present hazards to human health and are known for the production of a wide range of highly toxic metabolites-cyanotoxins, of which among the most common and most investigated are the microcystins. The toxicity of the family of microcystin congeners to animal and cell models has received much attention; however, less is known about their negative effects on human health, whether via acute or chronic exposure. Useful information may be acquired through epidemiological studies since they can contribute to knowledge of the relationships between cyanotoxins and human health in environmental settings. The aim of this review is to compile and evaluate the available published reports and epidemiological investigations of human health incidents associated with exposure to mass populations of cyanobacteria from throughout the world and to identify the occurrence and likely role of microcystins in these events. After an initial screening of 134 publications, 42 publications (25 on the chronic and 17 on the acute effects of cyanotoxins) describing 33 cases of poisonings by cyanobacterial toxins in 11 countries were reviewed. The countries were Australia, China, Sri Lanka, Namibia, Serbia, Sweden, UK, Portugal, Brazil, USA, and Canada. At least 36 publications link cyanobacteria/cyanotoxins including microcystins to adverse human health effects. The studies were published between 1960 and 2016. Although the scattered epidemiological evidence does not provide a definitive conclusion, it can serve as additional information for the medical assessment of the role of microcystins in cancer development and other human health problems. This paper discusses the major cases of cyanotoxin poisonings as well as the strengths, weaknesses, and importance of the performed epidemiological research. This study also proposes some recommendations for future epidemiological work.

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BackgroundThe objective of this study was to investigate independent risk factors (RFs) connected with healthcare-associated (HA) Clostridium difficile infection (CDI) in surgical patients, its frequency per surgical wards and in-hospital-mortality at a single hospital.MethodsRisk factors for the infection were prospectively assessed among surgical patients with laboratory confirmed HA CDI and compared with a control group without HA CDI.ResultsThe overall incidence rate of HA CDI was 2.6 per 10000 patient-days. Significant independent RFs for HA CDI were the use of carbapenems (P = 0.007, OR: 10.62, 95% CI: 1.93–58.4), the admission to intensive care unit (P = 0.004, OR:3.00, 95% CI:1.41–6.40), and the administration of 3rd generation cephalosporins (P = 0.014, OR:2.27, 95% CI:1.18–4.39). Patients with HA CDI had significantly higher in–hospital mortality compared to controls (P: 0.007; OR: 8.95; 95% CI: 1.84–43.43).ConclusionsCDI is an important HA infection in population of surgical patients and this study emphasizes the importance of the wise use of antibiotics, and other infection control strategies in order to prevent HA CDI, and to decrease the incidence and in-hospital mortality rate.

The results of our study are valuable confirmation of relations between risk factors and SSI in orthopedic patients. A decreasing incidence rate of SSI (from 4.6% to 1.6%) during a 4-year active surveillance approved its implementation as an important component of SSI reduction strategy.