Showing papers by "Juliana Calábria de Araújo published in 2020"

Effect of alkaline treatment on pathogens, bacterial community and antibiotic resistance genes in different sewage sludges for potential agriculture use.

Abstract: Alkaline treatment is widely used to reduce pathogens in sewage sludge in developing countries and guarantee that it is safe for use in agriculture. The aim of this study was to investigate the eff...

Evaluation of nitrogen removal and the microbial community in a submerged aerated biological filter (SABF), secondary decanters (SD), and horizontal subsurface flow constructed wetlands (HSSF-CW) for the treatment of kennel effluent.

Abstract: To ensure microbial activity and a reaction equilibrium with efficiency and energy saving, it is important to know the factors that influence microbiological nitrogen removal in wastewater. Thus, it was investigated the microorganisms and their products involved in the treatment of kennel effluents operated with different aeration times, phase 1 (7 h of continuous daily aeration), phase 2 (5 h of continuous daily aeration), and phase 3 (intermittent aeration every 2 h), monitoring chemical and physical parameters weekly, monthly microbiological, and qualitative and quantitative microbiological analyzes at the end of each applied aeration phase. The results showed a higher mean growth of nitrifying bacteria (NB) (106) and denitrifying bacteria (DB) (1022) in phase with intermittent aeration, in which better total nitrogen (TN) removal performance, with 33%, was achieved, against 21% in phase 1 and 17% in phase 2, due to the longer aeration time and lower carbon/nitrogen ratio (15.7), compared with the other phases. The presence of ammonia-oxidizing bacteria (AOB), the genus Nitrobacter nitrite–oxidizing bacteria (NOB), and DB were detected by PCR with specific primers at all phases. The analysis performed by 16S-rRNA DGGE revealed the genres Thauera at all phases; Betaproteobacteria and Acidovorax in phase 3; Azoarcus in phases 2 and 3; Clostridium, Bacillus, Lactobacillus, Turicibacter, Rhodopseudomonas, and Saccharibacteria in phase 1, which are related to the nitrogen removal, most of them by denitrifying. It is concluded that, with the characterization of the microbial community and the analysis of nitrogen compounds, it was determined, consistently, that the studied treatment system has microbiological capacity to remove TN, with the phase 3 aeration strategy, by simultaneous nitrification and denitrification (SND). Due to the high density of DB, most of the nitrification occurred by heterotrophic nitrification-aerobic. And denitrification occurred by heterotrophic and autotrophic forms, since the higher rate of oxygen application did not harm the DB. Therefore, the aeration and carbon conditions in phase 3 favored the activity of the microorganisms involved in these different routes. It is considered that, in order to increase autotrophic nitrification-aerobic, it is necessary to exhaust the volume of sludge in the secondary settlers (SD), further reducing the carbon/nitrogen ratio, through more frequent cleaning, whose periodicity should be the object of further studies.

Detecção e quantificação de bactérias resistentes aos antibióticos ampicilina e cloranfenicol em estações de tratamento de esgoto doméstico

Abstract: RESUMO Estacoes de tratamento de esgotos (ETEs) estao entre as principais fontes de disseminacao de bacterias resistentes a antibioticos (BRAs) e genes de resistencia (GRAs) no ambiente. Este trabalho quantificou a ocorrencia de bacterias resistentes aos antibioticos ampicilina e cloranfenicol no esgoto bruto (EB), no efluente tratado (ET) e no lodo de duas ETEs em escala plena por um periodo de nove meses. As unidades investigadas utilizavam os seguintes sistemas de tratamento: ETE-A, sistema de lodos ativados convencional; e a ETE-B, reatores anaerobios (UASB) seguidos de filtros biologicos percoladores (FBP). Os resultados evidenciaram que a ETE-A foi mais eficiente na reducao das concentracoes de bacterias resistentes a ampicilina e ao cloranfenicol (cerca de 1,1 e 0,7 log10UFC.mL−1 de remocao, respectivamente), quando comparada com a ETE-B (0,5log10 UFC.mL−1 de remocao para as bacterias resistentes ao cloranfenicol e nenhuma remocao para as resistentes a ampicilina). As amostras de lodo, de ambas ETEs, apresentaram elevadas concentracoes de bacterias heterotroficas totais — BHTs (4,8–7,6 log10UFC.mL−1) e de BRAs (3,0–6,3 log10UFC.mL−1). A maioria das cepas resistentes a ampicilina e ao cloranfenicol isoladas foi identificada como sendo da familia Enterobacteriaceae. Algumas das especies identificadas sao bacterias potencialmente patogenicas, tais como: Klebsiella pneumoniae, Aeromonas hydrophila, Escherichia coli, Enterococcus faecium, Salmonella spp. Os resultados chamam a atencao para a disseminacao de BRAs, potencialmente patogenicas, no meio ambiente a partir do efluente final (proveniente do tratamento secundario) das ETEs, independentemente do tipo de sistema adotado. Fica evidente que para reduzir significativamente a concentracao das BRAs no ET, este deveria passar por tratamento adicional e desinfeccao.

Antibiotic Resistance, Sanitation, and Public Health

Abstract: Antimicrobial resistance (AMR) poses a serious threat to global health. In countries with poor sanitation conditions, the situation is worrisome. In this chapter, worldwide data, particularly from Brazil, supports a discussion about the risks of sewage and livestock manure on spreading antibiotic resistance, calling attention to the relationship between poor sanitation conditions, water pollution, and public health. The role of wastewater treatment plants (WWTP) and different treatment technologies in reducing AMR from municipal and livestock wastewaters are discussed based on the information available. It has been observed that municipal WWTPs with tertiary treatment systems can be decisive in the prevention and control of AMR spread and thus contribute to the maintenance of environmental and public health. Considering the information provided, there is a potential for antibiotic-resistant bacteria and antibiotic resistance gene dissemination through conventional WWTP effluents and sludges, especially when the latter are used as biosolids. By reaching surrounding aquatic environments, antibiotic-resistant bacteria may arise as a threat for public health since WWTP and water treatment plants (WTP) are not normally designed to specifically remove AMR. In summary, globally and in particular, Brazil has a lot of challenges to monitor and control AMR not only in municipal WWTPs but also in clinical and natural environments. Accurate information provided by research and routine monitoring, political engagement, new policies, and multidisciplinary actions will be vital to tackle this problem. In the short term, the control of the antibiotic prescription and their use by the population and farmers (already in place) and the increase of sewage collection and treatment are strategic actions to reduce AMR and guarantee public health in the country.

Family planning among female medical students: are their plans comparable to other professionals?

Abstract: SUMMARY INTRODUCTION Late pregnancy is a problem among physicians, especially surgeons. This paper studies family planning among Medical Students (MS) and Law students (LS). METHODS A questionnaire was sent to all female MS and LS attending the two last years of University in the first semester of 2019. Data on age, family income, marital status, and family planning (age, planning for future pregnancies, timing, professional relationship or other issues, the ideal moment for a pregnancy, attitude towards eventual pregnancies, or maternity leave) were researched. RESULTS MS were significantly older than LS. A minority of women did not plan future pregnancies (10.6% of MS and 16.4% of LS), for markedly different reasons: 40% of the MS mentioned career plans, while for 70% of LS motherhood was not a personal project. The ages chosen for pregnancy also differed: MS tended to choose older ages. The most important priorities were financial planning and professional career for both groups, but specialization/post-graduation were only cited among MS. Both groups considered that the ideal moment for pregnancy was after professional consolidation in the job market. There were differences between MS that chose a surgical specialty and other MS. DISCUSSION MS tend to go through pregnancy late, especially students planning a surgical career. Professional issues are more influential over MS than LS. Medical educators and health managers must recognize there is a need to reconcile the medical career and motherhood as females represent > 50% of MS in Brasil.

Air-drying bed as an alternative treatment for UASB sludge under tropical conditions

Abstract: This study investigated the behaviour of pathogens and microbial indicators during dewatering of sludge from an upflow anaerobic sludge blanket (UASB) reactor treating real domestic wastewater under tropical conditions. The sludge was dewatered in air-drying beds during wet and dry seasons and was monitored for 90 days. Culture-based methods, direct microscopy identification and quantitative polymerase chain reaction assays, were used to evaluate pathogenic and microbiological indicator microorganisms in the sludge. Thermotolerant coliforms and coliphages (somatic and male F-specific) were monitored as bacterial and viral indicators, respectively. Pathogenic organisms monitored included Salmonella spp., Salmonella Typhimurium, Salmonella Enteritidis, pathogenic Escherichia coli strains (intimin-coding genes), Campylobacter jejuni, Cryptosporidium spp., adenovirus, and viable helminths eggs. Results revealed that microbial indicators did not show a significant variation between the dry and wet seasons, as it was verified for some pathogens. During the 90 days of sludge dewatering, the air-drying bed was able to remove microbial indicators and the pathogenic organisms E. coli, S. Typhimurium, and Cryptosporidium spp. (when present). Pathogenic C. jejuni, S. Enteriditis, and adenovirus decreased 0.5–1.7, 0.3–0.4, and 2.6–4.8 log units, respectively. These results highlight the potential of air-drying beds as a simple and low-cost process for sludge dewatering and hygienisation.