Browsing by Author "Santos, A."
Now showing 1 - 10 of 13
Results Per Page
Sort Options
- Distribution, abundance and ecology of ticks in Portugal mainland: data from five years of a surveillance program REVIVEPublication . Santos-Silva, M.M.; Santos, A.; Lopes de Carvalho, I.; Sousa, R.; Luz, T.; Parreira, L.; Chainho, L.; Gomes, M.S.; Milhano, N.; Osório, H.; Alves, M.J.; Núncio, M.S.; REVIVE WorkgroupREVIVE (National Network for Vector Surveillance) aims to: i) Monitor the activity of hematophagous arthropods; ii) Characterize the species and its seasonal occurrence; iii) Identify important pathogens in Public Health, depending on the density of the vectors, the level of infection or the introduction of exotic species to alert for control measures.
- Expression of adenosine kinase in human mesial temporal lobe epilepsy with hippocampal sclerosis: A preliminary studyPublication . Leal, B.; Rangel, R.; Chaves, J.; Carvalho, C.; Bettencourt, A.; Zenatti, L.; Santos, A.; Magalhães, T.; Martins da Silva, A.; Correia de Sá, P.; Martins da Silva, B.; Costa, P.P.Background: Adenosine is a ubiquitous homeostatic molecule that acts as an “endogenous neuromodulator”. Adenosine attenuates neuronal activity either presynaptically by inhibiting neurotransmitter release or by controlling neurotransmitter responsiveness at post-synaptic sites. Unbalanced adenosine metabolism has been implicated in pathological conditions such as epilepsy. Adenosine kinase (ADK), synthetized by astrocytes, is the key regulator of extracellular adenosine levels in the brain. Evidences from experimental studies support a role for ADK in brain injury associated with astrogliosis, a morphological hallmark of Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS). In fact, expression of astrocytic ADK was found to be increased in the hippocampus and temporal cortex of MTLE-HS patients. Overexpression of ADK decreases extracellular adenosine and consequently may cause seizures. The aim of this study was to characterize ADK gene expression in MTLE-HS patients. Methods: Previous studies used immunohistochemistry and Western blot analysis to investigate ADK expression. Here we quantified the expression levels of ADK by Real-Time PCR in the hippocampus (lesional and peri-lesional cortical area) of 10 MTLE-HS patients submitted to surgery as compared with 9 autopsy controls with no history of neurological disorders. Results: Our results showed that ADK expression levels were similar in the hippocampus and temporal cortex of MTLE-HS patients when compared to healthy controls. Conclusion: Our preliminary data demonstrate that ADK expression levels are not altered in MTLE-HS. These results do not preclude post-transcriptional ADK abnormalities at both protein and functional levels. Our results should be confirmed in a larger cohort as well as with complementary methodologies.
- Helicobacter pylori infection features in a paediatric gastroenterology reference centre in PortugalPublication . Oliveira, L.; Santos, A.; Oleastro, M.; Cabral, J.Aim : To describe H. pylori infecon features in a Portuguese paediatric gastroenterology reference centre over the last five years.
- Helicobacter pylori prevalence, histological and antibiotic resistance patterns among paediatric patients, at a single hospital in Lisbon, during a 5- year periodPublication . Santos, A.; Pereira, L.; Paixão, P.; Braga, A.C.; Oliveira, R.; Catarino, A.; Oleastro, M.Background : Decreasing prevalence of H. pylori infection has been reported worldwide, in parallel with the improvement in sociodemographic conditions. In contrast, in Portugal, there is still a high prevalence of infection, including in pediatric population, and of gastric carcinoma. Aim : This study aims to evaluate H. pylori prevalence, histological and antibiotic resistance patterns in symptomatic Portuguese children/adolescents attending a hospital in Lisbon.
- Human herpes virus 6B and mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS): is there a link?Publication . Leal, B.; Castelo Branco, R.; Rangel, R.; Chaves, J.; Carvalho, C.; Bettencourt, A.; Honavar, M.; Melo Pires, M.; Santos, A.; Magalhães, T.; Lopes, J.; Ramalheira, J.; Martins da Silva, A.; Costa, P.P.; Martins da Silva, B.Purpose: Human Herpesvirus 6 (HHV-6) is a ubiquitous virus acquired mainly during the first 2 years of life. Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS) is the most frequent pharmacoresistant epilepsy. One of the most common antecedents of MTLE-HS is febrile seizures (FS). Although the aetiology of MTLE-HS remains unclear, evidences suggest that HHV-6 infection could be implicated. The objective of this study was to investigate the presence of HHV-6B DNA in the hippocampus and adjoining temporal cortex of MTLE-HS patients submitted to surgery. Methods: A total of 22 MTLE-HS (13 females and nine males) cases were studied. The mean age at surgery was 39 9 years and mean age at onset of seizures was 10 6 years. These study cohort was compared to a group of 10 epileptic patients without MTLE-HS (six females, four males; mean age = 26 15 years) and with autopsy material from nine individuals without neurological disease. HHV-6B DNA was identified by real-time PCR with specific TaqMan probes. Results: We detected HHV-6B DNA in only one hippocampus from a MTLE-HS patient. This patient had a disease duration of 36 years and a history of febrile seizures in childhood. None of the non-MTLE or controls specimens showed positivity for HHV-6B. Conclusions: Our findings do not support a relevant etiologic role for HHV-6B in MTLE-HS, at least in this population. However, the possible role of viral infection in MTLE-HS epileptogenic process, in individual cases, cannot be excluded.
- Human, food and animal Campylobacter spp. isolated in Portugal: high genetic diversity and antibiotic resistance ratesPublication . Duarte, A.; Santos, A.; Manageiro, V.; Martins, A.; Fraqueza, M.J.; Caniça, Manuela; Domingues, F.; Oleastro, M.Infections by Campylobacter jejuni and Campylobacter coli are considered the major cause of bacterial gastroenteritis in humans, with food being the main source of infection. In this study, a total of 196 Campylobacter strains (125 isolates from humans, 39 from retail food and 32 from food animal sources) isolated in Portugal between 2009 and 2012 were characterised by multilocus sequence typing (MLST) and flaA short variable region (SVR) typing. Susceptibility to six antibiotics as well as the mechanisms underlying antibiotic resistance phenotypes was also studied. Based on MLST typing, C. coli strains were genetically more conserved, with a predominant clonal complex (CC828), than C. jejuni strains. In contrast, C. coli isolates were genetically more variable than C. jejuni with regard to flaA-SVR typing. A high rate of resistance was observed for quinolones (100% to nalidixic acid, >90% to ciprofloxacin) and, in general, resistance was more common among C. coli, especially for erythromycin (40.2% vs. 6.7%). In addition, most isolates (86%) were resistant to multiple antimicrobial families. Besides the expected point mutations associated with antibiotic resistance, detected polymorphisms in the cmeABC locus likely play a role in the multiresistant phenotype. This study provides for the first time an overview of the genetic diversity of Campylobacter strains from Portugal. It also shows a worrying antibiotic multiresistance rate and the emergence of Campylobacter strains resistant to antibiotics of human use.
- Human, food and animal Campylobacter spp. isolated in Portugal: high genetic diversity and antibiotic resistance ratesPublication . Duarte, A.; Santos, A.; Manageiro, V.; Martins, A.; Fraqueza, M.J.; Caniça, Manuela; Domingues, F.C.; Oleastro, M.Infections by Campylobacter jejuni and Campylobacter coli are considered the major cause of bacterial gastroenteritis in humans, with food being the main source of infection. In this study, a total of 196 Campylobacter strains (125 isolates from humans, 39 from retail food and 32 from food animal sources) isolated in Portugal between 2009 and 2012 were characterised by multilocus sequence typing (MLST) and flaA short variable region (SVR) typing. Susceptibility to six antibiotics as well as the mechanisms underlying antibiotic resistance phenotypes was also studied. Based on MLST typing, C. coli strains were genetically more conserved, with a predominant clonal complex (CC828), than C. jejuni strains. In contrast, C. coli isolates were genetically more variable than C. jejuni with regard to flaA-SVR typing. A high rate of resistance was observed for quinolones (100% to nalidixic acid, >90% to ciprofloxacin) and, in general, resistance was more common among C. coli, especially for erythromycin (40.2% vs. 6.7%). In addition, most isolates (86%) were resistant to multiple antimicrobial families. Besides the expected point mutations associated with antibiotic resistance, detected polymorphisms in the cmeABC locus likely play a role in the multiresistant phenotype. This study provides for the first time an overview of the genetic diversity of Campylobacter strains from Portugal. It also shows a worrying antibiotic multiresistance rate and the emergence of Campylobacter strains resistant to antibiotics of human use.
- A infeção humana por Campylobacter em Portugal: alguns dados epidemiológicosPublication . Duarte, A.; Santos, A.; Benoliel, J.; Domingues, F.; Oleastro, M.
- Investigação de um cluster de infeções por Clostridium difficile em contexto oncológicoPublication . Santos, A.; Isidro, J.; Lameiras, C.; Campilho, F.; Branca, R.; Campos, A.; Oleastro, M.A infeção por Clostridium difficile (ICD) é das infeções mais frequentemente associadas aos cuidados de saúde. A exposição prévia a antibióticos constitui o principal fator de risco para o desenvolvimento da ICD, sendo outros fatores a idade avançada e a existência de comorbilidades, como a imunossupressão. Apesar de o contacto entre indivíduos/transmissão cruzada constituir uma importante via de transmissão da ICD, tem sido demonstrado que uma parte significativa dos casos de ICD não está ligada a outros casos ocorridos no mesmo serviço hospitalar. Neste trabalho reportamos três casos de ICD ocorridos no Serviço de Transplantação de Medula Óssea do IPO do Porto, dois episódios ocorreram em dias consecutivos (28 e 29 de Outubro), o terceiro a 16 de Novembro, em 2015.
- Molecular and epidemiologic study of Clostridium difficile reveals unusual heterogeneity in clinical strains circulating in different regions in PortugalPublication . Santos, A.; Isidro, J.; Silva, C.; Boaventura, L.; Diogo, J.; Faustino, A.; Toscano, C.; Oleastro, M.Clostridium difficile infection (CDI) represents a great healthcare burden in developed countries. The emergence of the epidemic PCR ribotype (RT) 027 and its acquired fluoroquinolones resistance have accentuated the need for an active surveillance of CDI. Here we report the first countrywide study of CDI in Portugal with the characterization of 498 C. difficile clinical isolates from 20 hospitals in four regions in Portugal regarding RT, virulence factors and antimicrobial susceptibility. We identified 96 RTs with marked variations between and within regions, as only six RTs appeared in all four regions. RT027 was the most frequent RT overall (18.5%) and among healthcare facility-associated isolates (19.6%), while RT014 was the most common among community-associated isolates (12%). The north showed a high RT diversity among isolates and a low moxifloxacin (MXF) resistance rate (11.9%), being the only region in which RT027 was not predominant. In contrast, the isolates from the centre presented the highest RT027 frequency, and 53.4% were resistant to MXF. Overall, MXF resistance (33.2%) was associated (p <0.001) with the presence of binary toxin genes and mutations in tcdC regardless of the RT. Both traits appeared in almost 30% of the strains. RT027 showed a reduced susceptibility to metronidazole (p <0.01), and RT126 had higher minimum inhibitory concentrations to vancomycin (p = 0.03) compared to other RTs. The present study highlights an unusual heterogeneity of RTs in Portugal, with a high frequency of hypervirulent RTs and the emergence of virulence factors in non-027 RTs, emphasizing the need for a surveillance system for CDI in Portugal.