Ana Varela

Insights into the relationship between antimicrobial residues and bacterial populations in a hospital-urban wastewater treatment plant system

The relationship between antimicrobial residues, antibiotic resistance prevalence and bacterial community composition in hospital effluent and in the receiving wastewater treatment plant was studied. Samples from hospital effluent, raw inflow and final effluent of the receiving wastewater treatment plant were characterized for amoxicillin and ciprofloxacin resistance prevalence, content of heavy metals and antimicrobial residues and bacterial community structure, based on 16S rRNA gene PCR-DGGE analysis. The concentration of fluoroquinolones, arsenic and mercury was in general higher in hospital effluent than in raw inflow, while the opposite was observed for tetracyclines, sulfonamides and penicillin G. The prevalence of ciprofloxacin resistance was significantly higher in hospital effluent than in raw inflow. The concentration of antimicrobial residues was observed to be significantly correlated with the prevalence of antibiotic resistant bacteria and with variations in the bacterial community. Hospital effluent was confirmed as a relevant, although not unique, source of antimicrobial residues and antibiotic resistant bacteria to the wastewater treatment plant. Moreover, given the high loads of antibiotic residues and antibiotic resistant bacteria that may occur in hospital effluents, these wastewater habitats may represent useful models to study and predict the impact of antibiotic residues on bacterial communities.

Vancomycin resistant enterococci: From the hospital effluent to the urban wastewater treatment plant

Vancomycin is an important antibiotic to treat serious nosocomial enterococci infections. Human activities, in particular those related with clinical practices performed in hospitals, can potentiate the transfer and selection of clinically-relevant resistant bacteria such as vancomycin resistant enterococci (VRE). Indeed, previous studies demonstrated the occurrence of VRE in urban wastewater treatment plants and related environments (e.g. sewage, rivers). In this study, the occurrence of VRE in a hospital effluent and in the receiving urban wastewater treatment plant was investigated. Vancomycin and ciprofloxacin resistant bacteria occurred in the hospital effluent and in raw municipal inflow at densities of 10(3) to 10(2) CFU mL(-1), being significantly more prevalent in the hospital effluent than in the urban wastewater. Most of the VRE isolated from the hospital effluent belonged to the species Enterococcus faecalis and Enterococcus faecium and presented multidrug-resistance phenotypes to ciprofloxacin, tetracycline, erythromycin, and high-level gentamicin. The same pattern was observed in clinical isolates and in enterococci isolated from the final effluent of the urban wastewater treatment plant. These results show that hospital effluents discharged into urban wastewater treatment plants may be a relevant source of resistance spread to the environment.

Human health implications of clinically relevant bacteria in wastewater habitats

The objective of this review is to reflect on the multiple roles of bacteria in wastewater habitats with particular emphasis on their harmful potential for human health. Indigenous bacteria promote a series of biochemical and metabolic transformations indispensable to achieve wastewater treatment. Some of these bacteria may be pathogenic or harbour antibiotic resistance or virulence genes harmful for human health. Several chemical contaminants (heavy metals, disinfectants and antibiotics) may select these bacteria or their genes. Worldwide studies show that treated wastewater contain antibiotic resistant bacteria or genes encoding virulence or antimicrobial resistance, evidencing that treatment processes may fail to remove efficiently these bio-pollutants. The contamination of the surrounding environment, such as rivers or lakes receiving such effluents, is also documented in several studies. The current state of the art suggests that only some of antibiotic resistance and virulence potential in wastewater is known. Moreover, wastewater habitats may favour the evolution and dissemination of new resistance and virulence genes and the emergence of new pathogens. For these reasons, additional research is needed in order to obtain a more detailed assessment of the long-term effects of wastewater discharges. In particular, it is important to measure the human and environmental health risks associated with wastewater reuse.

Quinolone resistant Aeromonas spp. as carriers and potential tracers of acquired antibiotic resistance in hospital and municipal wastewater

Members of the genus Aeromonas are recognized carriers of antibiotic resistance in aquatic environments. However, their importance on the spread of resistance from hospital effluents to the environment is poorly understood. Quinolone resistant Aeromonas spp. (n = 112) isolated from hospital effluent (HE) and from raw (RWW) and treated wastewater (TWW) of the receiving urban wastewater treatment plant (UWTP) were characterized. Species identification and genetic intraspecies diversity were assessed based on the 16S rRNA, cpn60 and gyrB genes sequence analysis. The antibiotic resistance phenotypes and genotypes (qnrA, qnrB, qnrC, qnrD, qnrS, qnrVC; qepA; oqxAB; aac(6′)-Ib-cr; blaOXA; incU) were analyzed in function of the origin and taxonomic group. Most isolates belonged to the species Aeromonas caviae and Aeromonas hydrophila (50% and 41%, respectively). The quinolone and the beta-lactamase resistance genes aac(6′)-Ib-cr and blaOXA, including gene blaOXA-101, identified for the first time in Aeromonas spp., were detected in 58% and 56% of the isolates, respectively, with identical prevalence in HE and UWTP wastewater. In contrast, the gene qnrS2 was observed mainly in isolates from the UWTP (51%) and rarely in HE isolates (3%), suggesting that its origin is not the clinical setting. Bacterial groups and genes that allow the identification of major routes of antibiotic resistance dissemination are valuable tools to control this problem. In this study, it was concluded that members of the genus Aeromonas harboring the genes aac(6′)-Ib-cr and blaOXA are relevant tracers of antibiotic resistance dissemination in wastewater habitats, while those yielding the gene qnrS2 allow the traceability from non-clinical sources.

blaTEM and vanA as indicator genes of antibiotic resistance contamination in a hospital–urban wastewater treatment plant system

Four indicator genes were monitored by quantitative PCR in hospital effluent (HE) and in the raw and treated wastewater of the municipal wastewater treatment plant receiving the hospital discharge. The indicator genes were the class 1 integrase gene intI1, to assess the capacity of bacteria to be involved in horizontal gene transfer processes; blaTEM, one of the most widespread antibiotic resistance genes in the environment, associated with Enterobacteriaceae; vanA, an antibiotic resistance gene uncommon in the environment and frequent in clinical isolates; and marA, part of a locus related to the stress response in Enterobacteriaceae. Variation in the abundance of these genes was analysed as a function of the type of water, and possible correlations with cultivable bacteria, antimicrobial residue concentrations, and bacterial community composition and structure were analysed. HE was confirmed as an important source of blaTEM and vanA genes, and wastewater treatment showed a limited capacity to remove these resistance genes. The genes blaTEM and vanA presented the strongest correlations with culturable bacteria, antimicrobial residues and some bacterial populations, representing interesting candidates as indicator genes to monitor resistance in environmental samples. The intI1 gene was the most abundant in all samples, demonstrating that wastewater bacterial populations hold a high potential for gene acquisition.

Pregnancy after bariatric surgery: Maternal and fetal outcomes of 39 pregnancies and a literature review

We aimed to evaluate the impact of bariatric surgery (BS) on maternal and fetal outcomes.

Effect of different bariatric surgery type on the leukocyte formula

BACKGROUND Obesity is associated with higher leukocyte counts, whereas weight loss decreases these counts. It is unknown if different bariatric surgery (BS) types have different effects on leukocytes. OBJECTIVES The aim of the study was to determine predictors of leukocyte and their subset count variation in patients submitted to BS. SETTING Tertiary care university hospital, Porto, Portugal. METHODS This was a retrospective analysis of patients submitted to Roux-en-Y gastric bypass (RYGB), laparoscopic adjustable gastric banding (LAGB), or sleeve gastrectomy (SG). Leukocyte and subset counts were compared between baseline and 1-year postsurgery and between BS types. A multivariate linear regression model was built to study determinants of leukocyte and subset variation. RESULTS We analyzed 764 patients: 238 submitted to LAGB; 452 to RYGB, and 74 to SG. Mean age was 42 years and 86.6% were women. All BS types were associated with a decrease in leukocyte and neutrophil counts but the variation in body mass index and homeostatic model assessment (HOMA-IR) were the only variables independently associated with a decrease 1-year postsurgery. Monocytes increased in patients submitted to LAGB and decreased in those who underwent RYGB and SG. The BS type was independently associated with monocyte variation. Patients who underwent RYGB and SG had a decrease in monocyte counts of 77/µL and 62/µL, respectively, compared with LAGB. CONCLUSION Weight and insulin resistance are the main predictors of leukocyte and neutrophil variation after BS. The specific type of BS is a determinant of monocyte count variation independent of the amount of weight loss or the degree of insulin resistance improvement.

Preoperative thyroid function and weight loss after bariatric surgery

Thyroid function has an important role on body weight regulation. However, the impact of thyroid function on weight loss after bariatric surgery is still largely unknown. We evaluated the association between preoperative thyroid function and the excess weight loss 1 year after surgery, in 641 patients with morbid obesity who underwent bariatric surgery. Patients with a history of thyroid disease, treatment with thyroid hormone or antithyroid drugs and those with preoperative evaluation consistent with overt hypothyroidism or hyperthyroidism were excluded. The preoperative levels of TSH and FT4 were not associated with weight loss after bariatric surgery. The variation of FT3 within the reference range was also not associated with weight loss. In contrast, the subgroup with FT3 above the reference range (12.3% of patients) had a significantly higher excess weight loss than patients with normal FT3. This difference remained significant after adjustment for age, sex, BMI, type of surgery, TSH and FT4. In conclusion, we observed an association between high FT3 and a greater weight loss after bariatric surgery, highlighting a group of patients with an increased benefit from this intervention. Our results also suggest a novel hypothesis: the pharmacological modulation of thyroid function may be a potential therapeutic target in patients undergoing bariatric surgery.

Insulin resistance and sex hormone-binding globulin are independently correlated with low free testosterone levels in obese males

Male obesity is associated with decreased testosterone levels but the pathophysiological mechanisms behind this association are not completely understood. This study aimed to investigate the impact of hyperglycaemia/insulin resistance and sex hormone‐binding globulin (SHBG) levels on testosterone levels in a population of obese men. We investigated the impact of several clinical, anthropometric and analytic measures on testosterone levels in 150 obese males. Testosterone deficiency was present in 52.0% of the enrolled patients. This percentage dropped to 17.6% when only calculated free testosterone (FT) was accounted, as SHBG levels were correlated negatively with body mass index (r = −.20; p < .05). Older age (p < .05) and higher homoeostasis model assessment of insulin resistance (HOMA‐IR) (p < .01) and lower SHBG levels (p < .05) were independently correlated with lower FT. Weight and fasting plasma glucose lost their statistical significance after multivariate adjustment. Patients with type 2 diabetes mellitus and pre‐diabetes had lower FT than those with normal glucose tolerance (p < .05 and p < .01 respectively). Insulin resistance, and not hyperglycaemia and weight per se, seems to be the main determinant of low testosterone levels in obese males. Low SHBG levels are correlated with low FT even after HOMA‐IR adjustment. This suggests that SHBG can be associated with testosterone deficiency beyond the influence of insulin resistance unlike previously reported.

Vitamin D Levels in an Obese Population, before and after Bariatric Surgery

Background: Obesity has been associated with vitamin D deficiency. The purpose of this study was to evaluate vitamin D status in obese patients, before and after bariatric surgery, and to examine the relationship of 25(OH)D3 levels with anthropometric measurements and body fat. Methods: Laboratory values of 25(OH)D3, anthropometric measurements, body fat and demographics were retrospectively collected from 239 obese patients, 179 of whom had undergone bariatric surgery. Blood levels of 25(OH)D3 were correlated with anthropometric measurements, body fat, and with weight loss in patients undergone bariatric surgery. Results: The prevalence of vitamin D deficiency (3 and anthropometric measurements and body fat in both groups. Body mass index, gender and season were predictors of 25(OH)D3. Each body mass index increase of 1 kg/m2 was associated with a decrease of 0.5 ng/mL in 25(OH)D3. In addition, it was found a positive association between 25(OH)D3 and weight loss after bariatric surgery. Conclusion: The levels of vitamin D seem to be associated with obesity. This finding suggests the need for assessment of vitamin D status and oral vitamin D supplementation in this population.