Browsing by Author "Nunes, Olga C."
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- Acetobacter sicerae sp. nov., isolated from cider and kefir, and identification of species of the genus Acetobacter by dnaK, groEL and rpoB sequence analysisPublication . Li, Leilei; Wieme, Anneleen; Spitaels, Freek; Balzarini, Tom; Nunes, Olga C.; Manaia, Celia M.; Van Landschoot, Anita; De Vuyst, Luc; Cleenwerck, Ilse; Vandamme, PeterFive acetic acid bacteria isolates, awK9_3, awK9_4 (5LMG 27543), awK9_5 (5LMG 28092), awK9_6 and awK9_9, obtained during a study of micro-organisms present in traditionally produced kefir, were grouped on the basis of theirMALDI-TOFMS profile with LMG1530 and LMG1531T, two strains currently classified as members of the genus Acetobacter. Phylogenetic analysis based on nearly complete 16S rRNA gene sequences as well as on concatenated partial sequences of the housekeeping genes dnaK, groEL and rpoB indicated that these isolates were representatives of a single novel species together with LMG 1530 and LMG 1531T in the genus Acetobacter, with Acetobacter aceti, Acetobacter nitrogenifigens, Acetobacter oeni and Acetobacter estunensis as nearest phylogenetic neighbours. Pairwise similarity of 16S rRNA gene sequences between LMG 1531T and the type strains of the above-mentioned species were 99.7%, 99.1%, 98.4% and 98.2%, respectively. DNA–DNA hybridizations confirmed that status, while amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) data indicated that LMG 1531T, LMG 1530, LMG 27543 and LMG 28092 represent at least two different strains of the novel species. The major fatty acid of LMG 1531T and LMG 27543 was C18 : 1v7c. The major ubiquinone present was Q-9 and the DNA G+C contents of LMG 1531T and LMG 27543 were 58.3 and 56.7 mol%, respectively. The strains were able to grow on D-fructose and D-sorbitol as a single carbon source. They were also able to grow on yeast extract with 30% D-glucose and on standard medium with pH 3.6 or containing 1% NaCl. They had a weak ability to produce acid from Darabinose. These features enabled their differentiation from their nearest phylogenetic neighbours. The name Acetobacter sicerae sp. nov. is proposed with LMG1531T (5NCIMB 8941T) as the type strain
- Acinetobacter rudis sp. nov., isolated from raw milk and raw wastewaterPublication . Vaz-Moreira, Ivone; Novo, Ana; Hantsis-Zacharov, Elionora; Lopes, Ana Rita; Gomila, Margarita; Nunes, Olga C.; Manaia, Célia M.; Halpern, MalkaTwo bacterial strains, G30T and A1PC16, isolated respectively from raw milk and raw wastewater, were characterized using a polyphasic approach. Chemotaxonomic characterization supported the inclusion of these strains in the genus Acinetobacter, with Q-8 and Q-9 as the major respiratory quinones, genomic DNA G+C contents within the range observed for this genus(38–47 mol%) and C16 : 0, C18 : 1v9c and C16 : 1v7c/iso-C15 : 0 2-OH as the predominant fatty acids. The observation of 16S rRNA gene sequence similarity lower than 97% with other Acinetobacter species with validly published names led to the hypothesis that these isolates could represent a novel species. This hypothesis was supported by comparative analysis of partial sequences of the genes rpoB and gyrB, which showed that strains G30T and A1PC16 did not cluster with any species with validly published names, forming a distinct lineage. DNA–DNA hybridizations confirmed that the two strains were members of the same species, which could be distinguished from their congeners by several phenotypic characteristics. On the basis of these arguments, it is proposed that strains G30T and A1PC16 represent a novel species, for which the name Acinetobacter rudis sp. nov. is proposed. The type strain is strain G30T (5LMG 26107T 5CCUG 57889T 5DSM 24031T 5CECT 7818T).
- AlicycliphilusPublication . Nunes, Olga C.; Manaia, Célia M.; Vaz-Moreira, IvoneAlicycliphilus (A.li.cy.cli'phi.lus. Gr. neut. n. aleiphar annointing oil; Gr. masc. n. kyklos circle or ring; Gr. masc. n. philos friend; N.L. masc. n. Alicyciphilus alicyclic compound liking, referring to the substrates used for the isolation of this organism). Proteobacteria / Betaproteobacteria / Burkholderiales / Comamonadaceae / Alicycliphilus. Short rods, 1–2 μm long and 0.6 μm wide. Motile. Gram‐negative. Nonsporulating. Facultative anaerobe. Nitrate is reduced to N2. Mesophilic, with optimal growth at 28–30°C and pH 7.2–7.4 under aerobic or anoxic conditions. Chemoorganotroph, with strictly respiratory metabolism. Degrade aromatic and alicyclic compounds. Catalase‐ and cytochrome c oxidase‐positive. The respiratory quinone is ubiquinone 8, and major fatty acids are C16:1 ω7c, C16:0, and C18:1 ω7c. Major polar lipids are hosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The type strain of the type species was isolated from a wastewater treatment plant, cultivated with cyclohexanol as sole carbon source and nitrate as electron acceptor. DNA G + C content (mol%): 66 (HPLC) or 67.9 (genome analysis, GenBank). Type species: Alicycliphilus denitrificans Mechichi et al. 2003VP.
- Aminoglycoside resistance in ralstonia pickettiiPublication . Vaz-Moreira, Ivone; Ferro, Pompeyo; Nunes, Olga C.; Manaia, Célia M.
- Antibiotic resistance in urban aquatic environments: can it be controlled?Publication . Manaia, Célia; Macedo, Gonçalo; Fatta-Kassinos, Despo; Nunes, Olga C.Over the last decade, numerous evidences have contributed to establish a link between the natural and human-impacted environments and the growing public health threat that is the antimicrobial resistance. In the environment, in particular in areas subjected to strong anthropogenic pressures, water plays a major role on the transformation and transport of contaminants including antibiotic residues, antibiotic-resistant bacteria, and antibiotic resistance genes. Therefore, the urban water cycle, comprising water abstraction, disinfection, and distribution for human consumption, and the collection, treatment, and delivery of wastewater to the environment, is a particularly interesting loop to track the fate of antibiotic resistance in the environment and to assess the risks of its transmission back to humans. In this article, the relevance of different transepts of the urban water cycle on the potential enrichment and spread of antibiotic resistance is reviewed. According to this analysis, some gaps of knowledge, research needs, and control measures are suggested. The critical rationale behind the measures suggested and the desirable involvement of some key action players is also discussed.
- Antibiotic resistance in waste water and surface water and human health implicationsPublication . Manaia, C. M.; Vaz-Moreira, Ivone; Nunes, Olga C.The utilization of antibiotics to control infectious diseases is one of the biggest advances in human and veterinary health care. However, the generalized use of antibiotics has been accompanied by a worrisome increase in the prevalence of antibiotic-resistant bacteria. This evidence motivated numerous studies on the diversity and distribution of antibiotic-resistant bacteria and resistance genetic determinants not only in clinic but also in different environmental compartments. Given the particular importance that the anthropic water cycle (waste water/surface water/drinking water) may have in the development and dissemination of antibioticresistant organisms, this chapter aims at summarizing the recent advances in this area. Sections 1 and 2 are an Introduction to antibiotic resistance, summarizing some mechanisms and modes of resistance acquisition. In Sect. 3, the contribution of the environmental pollution and other anthropic pressures for antibiotic resistance evolution is discussed. The use of different methodologies and the limitations to achieve general conclusions on the characterization and quantification of antibiotic resistance in aquatic environments are examined in Sects. 4 and 7. Sections 5–7 summarize recent evidences on the widespread distribution of antibiotic resistance in different compartments of the anthropic water cycle. The scarcity of studies giving evidences on the direct effect of anthropic pressures on antibiotic resistance acquisition and maintenance in treated waste/drinking waters is highlighted. The contribution of bacterial community rearrangement, imposed by water treatment processes, on the increase of antibiotic resistance is discussed.
- Antibiotic resistance in wastewater treatment plants: tackling the black boxPublication . Manaia, Célia M.; Rocha, Jaqueline; Scaccia, Nazareno; Marano, Roberto; Radu, Elena; Biancullo, Francesco; Cerqueira, Francisco; Fortunato, Gianuário; Iakovides, Iakovos C.; Zammit, Ian; Kampouris, Ioannis; Vaz-Moreira, Ivone; Nunes, Olga C.Wastewater is among the most important reservoirs of antibiotic resistance in urban environments. The abundance of carbon sources and other nutrients, a variety of possible electron acceptors such as oxygen or nitrate, the presence of particles onto which bacteria can adsorb, or a fairly stable pH and temperature are examples of conditions favouring the remarkable diversity of microorganisms in this peculiar habitat. The wastewater microbiome brings together bacteria of environmental, human and animal origins, many harbouring antibiotic resistance genes (ARGs). Although numerous factors contribute, mostly in a complex interplay, for shaping this microbiome, the effect of specific potential selective pressures such as antimicrobial residues or metals, is supposedly determinant to dictate the fate of antibiotic resistant bacteria (ARB) and ARGs during wastewater treatment. This paper aims to enrich the discussion on the ecology of ARB&ARGs in urban wastewater treatment plants (UWTPs), intending to serve as a guide for wastewater engineers or other professionals, who may be interested in studying or optimizing the wastewater treatment for the removal of ARB&ARGs. Fitting this aim, the paper overviews and discusses: i) aspects of the complexity of the wastewater system and/or treatment that may affect the fate of ARB&ARGs; ii) methods that can be used to explore the resistome, meaning the whole ARB&ARGs, in wastewater habitats; and iii) some frequently asked questions for which are proposed addressing modes. The paper aims at contributing to explore how ARB&ARGs behave in UWTPs having in mind that each plant is a unique system that will probably need a specific procedure to maximize ARB&ARGs removal.
- Antibiotic resistance of enterococci and related bacteria in an urban wastewater treatment plantPublication . Silva, Miguel Ferreira da; Tiago, Igor; Veríssimo, António; Boaventura, Rui A. R.; Nunes, Olga C.; Manaia, Célia M.The main objective oflhis work was to study the ecology of enterooocci and related bacteria in raw and treated wastewater from a treatment plant receiving domestic and pretreated industrial effluents in order to assess the influence of treatment on the prevalence of antibiotic resistance phenotypes among this group ofbacteria. The predominant species found in the raw wastewater-were Erztercaccus hirae, Entercoc- cus faecium and Enrercnrcus faecalis. Wastewater treatment led to a reduction in E. hirae (ar < 0.1) and an increase Ln B fnecium [nt < [}_1); the relative proportions ofE. fczecalis remained the same in the raw and in the treated wastewater. Among the isolates tested, no vanoornyclln resistance was observed among the cnterococci. Entercoccus faecium and E. fneculis showed resistance prevalence values reaching 33%. 40% and 57% for the antibiotics ciprofloxacin, erythromycin and tetracycline, respectively. Antibiotieresistant strains of enterococci were not eliminated by wastewater treatment. A positive selection of ciprofloxacin-resistant enterococci was indicated by a significant increase in resistance prevalence (ac < 0.52) in treated wastewater compared with the raw wastewater.
- Antibiotic resistance, antimicrobial residues and bacterial community composition in urban wastewaterPublication . Novo, Ana; André, Sandra; Viana, Paula; Nunes, Olga C.; Manaia, Célia M.This study was based on the hypothesis that the occurrence of antimicrobial residues and antibiotic resistant bacteria in the sewage could be correlated with the structure and composition of the bacterial community and the antibiotic resistance loads of the final effluent. Raw and treated wastewater composite samples were collected from an urban treatment plant over 14 sampling dates. Samples were characterized for the i) occurrence of tetracyclines, penicillins, sulfonamides, quinolones, triclosan, arsenic, cadmium, lead, chromium and mercury; ii) antibiotic resistance percentages for tetracycline, sulfamethoxazole, ciprofloxacin and amoxicillin and iii) 16S rRNA gene-DGGE patterns. The data of corresponding samples, taking into account the hydraulic residence time, was analyzed using multivariate analysis. Variations on the bacterial community structure of the final effluent were significantly correlated with the occurrence of tetracyclines, penicillins, sulfonamides, quinolones and triclosan in the raw inflow. Members of the class Epsilonproteobacteria presented positive correlations with those antimicrobials, whereas negative correlations were observed with Beta and Gammaproteobacteria and Firmicutes. Antibiotic resistance percentages presented different trends of variation in heterotrophs/enterobacteria and in enterococci, varied over time and after wastewater treatment. Antibiotic resistance was positively correlated with the occurrence of tetracyclines residues and high temperature. A relationship between antibiotic residues, bacterial community structure and composition and antibiotic resistance is demonstrated. Further studies, involving more wastewater treatment plants may help to elucidate this complex relationship.
- Antimicrobial resistance patterns inEnterobacteriaceae isolated froman urbanwastewater treatment plantPublication . Silva, Miguel Ferreira da; Vaz-Moreira, Ivone; Gonzalez-Pajuelo, Maria; Nunes, Olga C.; Manaia, Célia M.Over 18 months, enterobacteria were isolated from the raw (189 isolates) and treated (156 isolates) wastewater of a municipal treatment plant. The isolates were identified as members of the genera Escherichia (76%), Shigella (7%), Klebsiella (12%) and Acinetobacter (4%). Antimicrobial susceptibility phenotypes were determined using the agar diffusion method for the antibiotics amoxicillin, gentamicin, ciprofloxacin, sulfamethoxazole/trimethoprim, tetracycline and cephalothin, the disinfectants hydrogen peroxide, sodium hypochlorite, quaternary ammonium/formaldehyde and iodine, and the heavy metals nickel, cadmium, chromium, mercury and zinc. Class 1 integrons were detected by PCR amplification using the primers CS5 and CS3. Compared with the raw influent, the treated wastewater presented higher relative proportions of Escherichia spp. isolates resistant to ciprofloxacin and cephalothin (Po0.0001 and Po0.05, respectively). Except for mercury, which showed a positive correlation with tetracycline and sulfamethoxazole/trimethoprim, no significant positive correlations were observed between antibiotic, disinfectant and heavy metal resistance. The variable regions of class 1 integrons, detected in c. 10% of the Escherichia spp. isolates, contained predominantly the gene cassettes aadA1/dhfrI.