DDI - Capítulos (ou partes) de livros
Permanent URI for this collection
Browse
Recent Submissions
- Exposure to Fungi in Health Care FacilitiesPublication . Sabino, RaquelThe number of nosocomial fungal infections is increasing due to several factors, but especially due to the higher number of immunocompromised patients, advances in medicine such as the increasing number of invasive procedures and treatments and longer stays within health care facilities. Air and surfaces of those facilities, health-care workers’ hands, and contaminated medical products are some of the main sources of fungi and associated with nosocomial infection. Aspergillus and Candida species are responsible for the majority of the cases of nosocomial fungal infections in immunocompromised patients. However, other fungi have emerged, namely Fusarium species, Pseudallescheria boydii, species belonging to the subphylum Mucormicotina, and yeasts like Malassezia or Saccharomyces. Some of these emerging pathogens are, in some cases, resistant to the available antifungals, potentiating the threat of novel fungal diseases. In this chapter, some of these etiological agents, associated infections, transmission routes and potential sources of infection in health care facilities will be discussed. In addition, collection procedures and new methods of laboratory analysis will also be mentioned.
- Overview of Clostridium difficile Infection: Life Cycle, Epidemiology, Antimicrobial Resistance and TreatmentPublication . Isidro, Joana; Mendes, Aristides L.; Serrano, Mónica; Henriques, Adriano O.; Oleastro, MónicaThe use of antimicrobial agents and acquired resistances explains in part the emergence and spreading of epidemic strains of Clostridium difficile. Continued use of antimicrobial therapy still represents an acute danger in triggering the emergence and spreading of new resistant and multiresistant strains including against first line antibiotics. We examine the pathway of peptidoglycan synthesis in this organism and associated resistances, as well as resistance to other classes of antibiotics. The life-cycle of C. difficile involves growth, spore formation and germination. Spores endow the organism with a formidable capacity of persistence in the environment and in the host, resistance, dissemination and infectious potential. Highly resistant spores produced by antibiotic resistant/multiresistant strains may be one of the most serious challenges we face in what concerns the containment of C. difficile. Finally, we review recent developments in treatment and prevention of C. difficile infection.
- Antifungal ResistancesPublication . Sabino, RaquelThe increasing number of invasive procedures and clinical therapies has led to an increase number of patients at-risk of suffering invasive fungal infections. The prophylaxis with antifungals is now broader used in specic groups of patients. Therefore, it is not surprising the emergence of antifungal resistance. In the follow- ing chapter this issue will be discussed, raising awareness to possible sources as well as modes of transmission of resistant isolates in specic environmental settings.
- Bacterial resistancesPublication . Manageiro, Vera; Salgueiro, Vanessa; Ferreira, Eugénia; Caniça, ManuelaHere we review several factors involved in the emergence of antibiotic resistance. They are numerous, and the constant adaptation of microorganisms to the selective pressure exerted by antibiotics is extraordinary. The monitoring systems to assess antibiotic resistance levels and the extent of dissemination were highlighted. In addition, the success of spread of certain bacterial lineages and resistant mechanisms remains sometimes difficult to determine. The need to enlarge research in the area of antibiotic resistance was also stated, not only to better understand the dynamics of dissemination of resistance between different bacteria and different ecosystems, but also to enlarge the pharmaceutical pipeline of antibacterials against multidrug-resistant pathogens. It is manifest the severe consequences of antibiotic resistances to humans, animals and environment, constituting a global public health priority. In consequence, it should be tackled on all fronts in view to the essential concept of “One World-One Medicine-One Health”.
- Probiotics as an Alternative Therapy for Helicobacter pylori-Associated DiseasesPublication . Vale, F.F.; Vítor, J.; Oleastro, M.Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit to the host. Probiotics are not part of the current treatment therapies prescribed for Helicobacter pylori eradication, but there are numerous studies, most of them using probiotics as adjuvants to therapy, showing a reduction of side effects in the greater majority of cases. The probiotics administered vary hugely in the composition of microorganisms used, as well as the duration and mode of administration, which renders the comparison difficult. However, the most used probiotics for H. pylori infection are composed of Lactobacillus, Bifidobacterium, Saccharomyces, and Streptococcus. The mode of action of these probiotics relies on competition for nutrients and for adhesion to cell receptors, antimicrobial activity, and modulation of the immune system and microbiota.
- Molecular epidemiology of carbapenemase resistant Klebsiella pneumoniaePublication . Jones-Dias, Daniela; Caniça, Manuela; Manageiro, VeraCarbapenem-resistant Klebsiella pneumoniae have emerged as a class of pathogens that pose a significant threat to patients admitted to healthcare facilities. This phenotype is mostly due to the production of carbapenemases, which constitute the group of β-lactamases capable of hydrolysing all β-lactam antibiotics, including carbapenems. However, the successful worldwide dissemination of carbapenem resistant K. pneumoniae has been linked to the emergence of a specific type of carbapenemase: KPC (K. pneumoniae carbapenemase). Although this carbapenemase has been identified in several sequence-types (STs), the pandemic seems to be mainly driven by the spread of KPC-producing K. pneumoniae from ST258. Apart from the triumph of the clonal spread, there is a considerable variability in the number of mobile genetic elements that KPC-producing K. pneumoniae might harbour, and that contribute to the mobilization and transference of the KPC-encoding gene (blaKPC). This transmission can be mediated by different molecular mechanisms that include the mobilization of minor genetic elements and the horizontal transfer of different conjugative plasmids. Tn4401 transposon is highly involved in the horizontal dissemination of blaKPC. This transposon can even assume different isoforms that, in turn, may become associated with multiple blaKPC-bearing plasmids. Although many plasmids have been linked to the dissemination of blaKPC gene, the incompatibility groups enclosing Tn4401 seem to be predominant. In K. pneumoniae, other carbapenem resistance determinants have been identified throughout the years but none has disseminated to the extent of KPC. Its spread and success seems to be multifactorial with virulence factors, antibiotic resistance determinants and mobile genetic elements playing major roles. Only the early detection of these factors may ease their establishment worldwide and prevent their emergence in non endemic countries.
- Arcobacter spp. in food chain – From culture to omicsPublication . Ferreira, S.; Oleastro, M.; Domingues, F.Book description by editor: Food is an essential means for humans and other animals to acquire the necessary elements needed for survival. However, it is also a transport vehicle for foodborne pathogens, which can pose great threats to human health. Use of antibiotics has been enhanced in the human health system; however, selective pressure among bacteria allows the development for antibiotic resistance. Foodborne Pathogens and Antibiotic Resistance bridges technological gaps, focusing on critical aspects of foodborne pathogen detection and mechanisms regulating antibiotic resistance that are relevant to human health and foodborne illnesses This groundbreaking guide: - Introduces the microbial presence on variety of food items for human and animal consumption; - Provides the detection strategies to screen and identify the variety of food pathogens in addition to reviews the literature; - Provides microbial molecular mechanism of food spoilage along with molecular mechanism of microorganisms acquiring antibiotic resistance in food; - Discusses systems biology of food borne pathogens in terms of detection and food spoilage; - Discusses FDA’s regulations and Hazard Analysis and Critical Control Point (HACCP) towards challenges and possibilities of developing global food safety. Foodborne Pathogens and Antibiotic Resistance is an immensely useful resource for graduate students and researchers in the food science, food microbiology, microbiology, and industrial biotechnology.
- Polyclonal KPC-3-producing Enterobacteriaceae in PortugalPublication . Manageiro, Vera; Ferreira, Eugénia; Louro, Deolinda; The Antimicrobial Resistance Surveillance Program in Portugal; Caniça, ManuelaAll 6 KPC-3-producing Enterobacteriaceae isolates (5 K. pneumoniae and 1 Enterobacter cloacae), identified among 61 isolates, from different Portuguese health institutions (March 2010 to December 2011) were multidrug resistant, showing susceptibility only to colistin. The blaKPC-3 gene, conferring resistance to carbapenemes, was present alone or in combination with other bla genes: blaSHV-26, blaCTX-M-15, and the ESBL blaSHV-164, here firstly described. The Tn4401-harbouring blaKPC-3 encountered in all isolates, showed a 68 bp deletion upstream of the bla gene. All but two KPC-3-containing plasmids revealed the following types: IncFrepB plus IncFIIs (n=3) and IncFrepB plus IncP (n=1). Dissemination of blaKPC seems to be due to carriage of similar KPC-harbouring plasmids within genetically distinct K. pneumoniae (ST14, ST34, ST59, ST416 and the novel ST960, by MLST) and E. cloacae clinical strains.
- Comparison of fungal contamination between hospitals and companies food unitsPublication . Viegas, C.; Ramos, C.; Almeida, M.; Sabino, R.; Verissimo, C.; Rosado, L.A descriptive study was developed to compare air and surfaces fungal contamination in ten hospitals’ food units and two food units from companies. Fifty air samples of 250 litres through impaction method were collected from hospitals’ food units and 41 swab samples from surfaces were also collected, using a 10 by 10 cm square stencil. Regarding the two companies, ten air samples and eight surface samples were collected. Air and surface samples were collected in food storage facilities, kitchen, food plating and canteen. Outdoor air was also collected since this is the place regarded as a reference. Simultaneously, temperature, relative humidity and meal numbers were registered. Concerning air from hospitals’ food units, 32 fungal species were identified, being the two most commonly isolated genera Penicillium sp.
- Assessment of fungal contamination in a Portuguese maternity unitPublication . Viegas, C.; Sabino, R.; Veríssimo, C.; Rosado, L.A descriptive study was developed to monitor air fungal contamination in one Portuguese maternity. Sixty air samples were collected through impaction method. Air sampling was performed in food storage facilities, kitchen, food plating, canteen, pharmacy, sterilization areas, genecology wards, intensive care unit, operating rooms, urgency and also, outside premises, since this was the place regarded as reference. Besides air samples, forty three samples were collected by swabbing the surfaces using a 10 by 10 cm square stencil. Simultaneously, temperature, relative humidity and particles counting (PM10) were registered. Twenty three species of fungi were identified in air, being the two most commonly isolated the genera Penicillium (41,5%) and Cladosporium (28,4%). Regarding yeasts, only Rhodotorula sp. (45,2%), Trichosporon mucoides (51,6%) and Cryptococcus neoformans (3,2%) were found. Thirteen species of fungi were identified in surfaces, being the most frequent the Penicillium genus (91,6%). Concerning yeasts found in surfaces, four species were identified being Rhodotorula sp. (29,1%) the most frequent. There was no coincidence between prevailing genera indoors and outside premises. Moreover, some places presented fungal species different from the ones isolated outside. In the inside environment, Aspergillus species were isolated in air and surfaces. There was no significant relationship (p>0,05) between fungal contamination and the studied environmental variables. Keywords: air, surfaces, fungal contamination, environmental variables, maternity.