Introduction: On the eleventh of March 2020, the World Health Organization (WHO) declared the novel coronavirus disease 2019 (COVID-19) a pandemic by the number of cases and deaths worldwide: more than 91.1 million confirmed cases and approx. 1.9 million deaths globally, as of date. The aims of this systematic review were to identify and to evaluate the reports associated on Knowledge, Attitude and Practices (KAP) towards COVID-19 pandemic in America. Methodology: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were adopted for searching reports published from December 2019 to September 2020, regarding “COVID-19 KAP” across six electronic databases. Inclusion and exclusion criteria were taken up to select the articles and focus to the topic. Results: Thirteen scientific papers were finally eligible and included in this systematic review. The surveys were directed to common citizens, healthcare workers and patients with chronic conditions. General public acquired information about COVID-19 mainly through social media; several misconceptions due to falsehoods circulating on-line were identified. The pandemic COVID-19 has severely affected the physical and emotional health of many people in America. Nevertheless, many American citizens do not recognize or have poor knowledge about COVID-19 risks. Conclusions: This systematic review brings information for governments and scientific community that may be useful in the development of official awareness and prevention campaigns aiming mainly at marginated groups of the society.

This present study aimed to characterize the bacterial community in a well-established nitrifying reactor by high-throughput sequencing of 16S rRNA amplicons. The laboratory-scale continuous stirred tank reactor has been supplied with ammonium (NH4+) as sole energy source for over 5 years, while no organic carbon has been added, assembling thus a unique planktonic community with a mean NH4+ removal rate of 86 ± 1.4 mg NH4+-N/(L d). Results showed a nitrifying community composed of bacteria belonging to Nitrosomonas (relative abundance 11.0%) as the sole ammonia oxidizers (AOB) and Nitrobacter (9.3%) as the sole nitrite oxidizers (NOB). The Alphaproteobacteria (42.3% including Nitrobacter) were the most abundant class within the Proteobacteria (62.8%) followed by the Gammaproteobacteria (9.4%). However, the Betaproteobacteria (excluding AOB) contributed only 0.08%, confirming that Alpha- and Gammaproteobacteria thrived in low-organic-load environments while heterotrophic Betaproteobacteria are not well adapted to these conditions. Bacteroidetes, known to metabolize extracellular polymeric substances produced by nitrifying bacteria and secondary metabolites of the decayed biomass, was the second most abundant phylum (30.8%). It was found that Nitrosomonas and Nitrobacter sustained a broad population of heterotrophs in the reactor dominated by Alpha- and Gammaproteobacteria and Bacteroidetes, in a 1:4 ratio of total nitrifiers to all heterotrophs.