Instituto Nacional Of Enfermedades Infecciosas

Buenos Aires, Argentina

Instituto Nacional Of Enfermedades Infecciosas

Buenos Aires, Argentina
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Chan P.K.S.,Chinese University of Hong Kong | Picconi M.A.,Instituto Nacional Of Enfermedades Infecciosas | Cheung T.H.,Prince of Wales Hospital | Giovannelli L.,Sezione di Microbiologia | Park J.S.,Catholic University of Korea
Critical Reviews in Clinical Laboratory Sciences | Year: 2012

Human papillomavirus (HPV) infection is associated with a wide spectrum of disease that ranges from self-limited skin warts to life-threatening cancers. Since HPV plays a necessary etiological role in cervical cancer, it is logical to use HPV as a marker for early detection of cervical cancer and precancer. Recent advances in technology enable the development of high-throughput HPV assays of different formats, including DNA-based, mRNA-based, high-risk group-specific and type-specific methods. The ultimate goal of these assays is to improve the accuracy and cost-effectiveness of cervical screening programs. HPV testing has several potential advantages compared to cytology-based screening. However, since the cancer to transient infection ratio is always low in the general population, HPV test results are bound to have a low positive predictive value that may subject women to unnecessary follow-up investigations. The wide-spread administration of prophylactic HPV vaccine will substantially decrease the incidence of cancer and precancer. This poses a number of challenges to cytology-based screening, and the role of HPV testing is expected to increase. Finally, apart from technical and cost-effectiveness considerations, one should also keep in mind the psycho-social impact of using sexually-transmitted agents as a marker for cancer screening. © 2012 Informa Healthcare USA, Inc.

Ritacco V.,Instituto Nacional Of Enfermedades Infecciosas | Lopez B.,Instituto Nacional Of Enfermedades Infecciosas | Ambroggi M.,Hospital Dr Fj Muniz | Palmero D.,Hospital Dr Fj Muniz | And 4 more authors.
Emerging Infectious Diseases | Year: 2012

During 2003-2009, the National Tuberculosis (TB) Laboratory Network in Argentina gave 830 patients a new diagnosis of multidrug-resistant (MDR) TB and 53 a diagnosis of extensively drug- resistant (XDR) TB. HIV co-infection was involved in nearly one third of these cases. Strain genotyping showed that 7 major clusters gathered 56% of patients within restricted geographic areas. The 3 largest clusters corresponded to epidemic MDR TB strains that have been undergoing transmission for >10 years. The indigenous M strain accounted for 29% and 40% of MDR and XDR TB cases, respectively. Drug-resistant TB trends in Argentina are driven by spread of a few strains in hotspots where the rate of HIV infection is high. To curb transmission, the national TB program is focusing stringent interventions in these areas by strengthening infection control in large hospitals and prisons, expediting drug resistance detection, and streamlining information-sharing systems between HIV and TB programs.

Abbate E.,University of Buenos Aires | Vescovo M.,University of Buenos Aires | Natiello M.,University of Buenos Aires | Cufre M.,University of Buenos Aires | And 7 more authors.
Journal of Antimicrobial Chemotherapy | Year: 2012

Objectives: Current drug choices to treat extensively drug-resistant (XDR) tuberculosis (TB) are scarce; therefore, information on the safety, tolerability and efficacy of alternative regimens is of utmost importance. The aim of this study was to describe the management, drug adverse effects and outcome of alternative combined treatment in a series of XDR-TB patients. Patients and methods: A retrospective study was performed on 17 non-AIDS, pulmonary adult patients with XDR-TB admitted to a referral treatment centre for infectious diseases in Buenos Aires from 2002 through 2008. Drug susceptibility testing was performed under regular proficiency testing and confirmed at the national TB reference laboratory. Results: Linezolid was included in the drug regimens of all patients; moxifloxacin and/or thioridazine were included in the regimens of 14 patients. Clinically tractable drug adverse effects were observed in nine patients, the most frequent being haematological disorders and neurotoxicity. In two patients, thioridazine was discontinued. Negative culture conversion was achieved in 15 patients, 11 completed treatment meeting cure criteria, 4 are still on follow-up with good evolution, 1 defaulted treatment and 1 was lost to follow-up. Conclusions: The combination of linezolid, moxifloxacin and thioridazine is recommended for compassionate use in specialized centres with expertise in the management of XDR-TB. ©The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

Romero M.M.,Inmunologia de enfermedades respiratorias | Basile J.I.,Inmunologia de enfermedades respiratorias | Lopez B.,Instituto Nacional Of Enfermedades Infecciosas | Ritacco V.,Instituto Nacional Of Enfermedades Infecciosas | And 3 more authors.
BMC Infectious Diseases | Year: 2014

Background: Neutrophils (PMN) are the first cells to infiltrate the lung after infection, and they play a significant protective role in the elimination of pathogen, by releasing preformed oxidants and proteolytic enzymes from granules and generating ROS, thus limiting inflammation by succumbing to apoptosis. In a previous study, we found marked differences in ROS-induced apoptosis between two Mycobacterium tuberculosis (Mtb) strains, M and Ra, representative of widespread Mtb families in South America, i.e. Haarlem and Latin-American Mediterranean (LAM), being strain M able to generate further drug resistance and to disseminate aggressively.Methods: In this study we evaluate the nature of bacteria-PMN interaction by assessing ROS production, apoptosis, lipid raft coalescence, and phagocytosis induced by Mtb strains.Results: Dectin-1 and TLR2 participate in Mtb-induced ROS generation and apoptosis in PMN involving p38 MAPK and Syk activation with the participation of a TLR2-dependent coalescence of lipid rafts. Further, ROS production occurs during the phagocytosis of non-opsonized bacteria and involves α-glucans on the capsule. In contrast, strain M lacks the ability to induce ROS because of: 1) a reduced phagocytosis and 2) a failure in coalescence of lipid raft.Conclusions: The differences in wall composition could explain the success of some strains which stay unnoticed by the host through inhibition of apoptosis and ROS but making possible its replication inside PMN as a potential evasion mechanism. Innate immune responses elicited by Mtb strain-to-strain variations need to be considered in TB vaccine development. © 2014 Romero et al.

Gomez S.A.,Instituto Nacional Of Enfermedades Infecciosas | Abrey-Recalde M.J.,CONICET | Panek C.A.,CONICET | Ferrarotti N.F.,University of Buenos Aires | And 6 more authors.
Clinical and Experimental Immunology | Year: 2013

Typical haemolytic uraemic syndrome (HUS) is caused by Shiga toxin (Stx)-producing Escherichia coli infections and is characterized by thrombotic microangiopathy that leads to haemolytic anaemia, thrombocytopenia and acute renal failure. Renal or neurological sequelae are consequences of irreversible tissue damage during the acute phase. Stx toxicity and the acute inflammatory response raised by the host determine the development of HUS. At present there is no specific therapy to control Stx damage. The pathogenic role of reactive oxygen species (ROS) on endothelial injury has been largely documented. In this study, we investigated the in-vivo effects of Stx on the oxidative balance and its contribution to the development of HUS in mice. In addition, we analysed the effect of anti-oxidant agents as therapeutic tools to counteract Stx toxicity. We demonstrated that Stx induced an oxidative imbalance, evidenced by renal glutathione depletion and increased lipid membrane peroxidation. The increased ROS production by neutrophils may be one of the major sources of oxidative stress during Stx intoxication. All these parameters were ameliorated by anti-oxidants reducing platelet activation, renal damage and increasing survival. To conclude, Stx generates a pro-oxidative state that contributes to kidney failure, and exogenous anti-oxidants could be beneficial to counteract this pathogenic pathway.© 2013 British Society for Immunology, Clinical and Experimental Immunology.

Degiuseppe J.I.,Instituto Nacional Of Enfermedades Infecciosas | Parra G.I.,National University of Asunción | Stupka J.A.,Instituto Nacional Of Enfermedades Infecciosas
PLoS ONE | Year: 2014

Seasonal shifts in the predominant strains and the periodic emergence of new strains are epidemiological features of human rotaviruses. After the sporadic detection in two samples in 1998, G3P[8] strains reemerged as the predominant rotavirus during 2008-2009 in Argentina. Notably, in 2011 6.3% (37/587) of samples presented the G3P[6] genotypes, which coincided with the recent detection of G3P[6] and G2P[6] strains in South America and Europe. Analyses of the 11 gene segments of four G3P[8] and two G3P[6] strains revealed that G3P[8] strains detected a decade apart (1998 and 2009) presented minor differences, while the G3P[6] strains presented a complete different genomic constellation albeit showing a similar VP7 gene. This study provides insights in the dynamics and evolution of one of the genotypes with the wider range of hosts and inter-species transmission potential. ©2014 Degiuseppe et al.

Stupka J.A.,Instituto Nacional Of Enfermedades Infecciosas | Degiuseppe J.I.,Instituto Nacional Of Enfermedades Infecciosas | Parra G.I.,National University of Asunción
Journal of Clinical Virology | Year: 2012

Background: Group A rotaviruses are the leading cause of non-bacterial severe diarrhea disease in infants and young children. In humans, the most common genotypes are G1-G4 and G9. Recently, G12 strains have been sporadically reported in several countries, including Argentina, Brazil and Paraguay. Objectives: To analyze rotavirus strain diversity in Argentina during 2008-2009 and to describe the whole genome-based classification of emerging G12P[8] strains detected in our country. Study design: Rotavirus positive-samples (n= 544) were collected from Argentinean children during 2008-2009, as a part of the National Surveillance Network for Viral Diarrheas. Specimens were genotyped by reverse transcription-polymerase chain reaction (RT-PCR) followed by nested-multiplex PCR. Sequencing of 11 genome segments was performed in 3 randomly selected G12P[8] strains. Results: G9P[8] was the most frequent strain in 2008, but in 2009 G3P[8] and G12P[8] were the most frequent strains in different geographical regions of the country. The novel emerging G12P[8] strains presented the following combination of genes: G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 (i.e. genotype1, Wa-like strains). The phylogenetic analysis of the VP7 gene of the G12P[8] strains grouped them within lineage III. Previously reported Argentinean G12P[9] strains presented genes from genotype 3 (AU-1-like strains) with a VP7 gene from lineage II. Conclusions: The emergence of G12P[8] rotaviruses was due to the introduction of a new strain, rather than to a reassortment of the G12P[9] strains previously circulating in our country. This study assesses the temporal and geographical changes in genotypes prevalence as well as the periodic emergence of unusual G genotypes. © 2012 Elsevier B.V.

Martinez V.P.,Instituto Nacional Of Enfermedades Infecciosas | Padula P.J.,Instituto Nacional Of Enfermedades Infecciosas
Journal of Medical Virology | Year: 2012

Andes virus (ANDV) is responsible for the Hantavirus Pulmonary Syndrome cases in Argentina and neighboring countries, with moderate to high case-fatality rates. ANDV has some particular features, which make it unique among other members of the Hantavirus genus such as person-to-person transmission and causing a disease similar to Hantavirus Pulmonary Syndrome in the hamster as an animal model. The kinetics of replication in Vero E6 cells of an ANDV strain isolated in Argentina, called Andes/ARG, was studied. Cytopathic effect and the formation of clear plaques were observed and therefore Andes/ARG could be quantified by classic plaque assay. The Andes/ARG strain was found to be highly lethal in Syrian hamsters allowing experiments to demonstrate the protective potential of vaccines. A recombinant nucleocapsid protein of ANDV induced a long lasting antibody response and protective immunity against a homologous challenge, but to a lower extent against heterologous challenge by the Seoul virus. © 2011 Wiley Periodicals, Inc.

Krivokapich S.J.,Instituto Nacional Of Enfermedades Infecciosas | Gonzalez Prous C.L.,Instituto Nacional Of Enfermedades Infecciosas | Gatti G.M.,Instituto Nacional Of Enfermedades Infecciosas | Saldia L.,Hospital Dr Jose Formenti
Veterinary Parasitology | Year: 2015

Prior to this study, only encapsulated species of Trichinella had been found in South America, i.e., T. spiralis and T. patagoniensis. Here we report the molecular identification of a non-encapsulated isolate of Trichinella from a domestic pig in Argentina. The multiplex PCR technique and the analysis of mitochondrial and nuclear DNA sequences revealed that it belongs to T. pseudospiralis, which parasitises birds and mammals from Australian, Nearctic, and Palaearctic regions. Interestingly, the isolate is closely related to the Palaearctic population. This is the first report of a non-encapsulated species of Trichinella from the Neotropical region. © 2015 Elsevier B.V.

Pasteran F.,Instituto Nacional Of Enfermedades Infecciosas | Gonzalez L.J.,National University of Rosario | Albornoz E.,Instituto Nacional Of Enfermedades Infecciosas | Bahr G.,National University of Rosario | And 2 more authors.
Journal of Clinical Microbiology | Year: 2016

Accurate detection of carbapenemase-producing Gram-negative bacilli is of utmost importance for the control of nosocomial spread and the initiation of appropriate antimicrobial therapy. The modified Hodge test (MHT), a carbapenem inactivation assay, has shown poor sensitivity in detecting the worldwide spread of New Delhi metallo--lactamase (NDM). Recent studies demonstrated that NDM is a lipoprotein anchored to the outer membrane in Gram-negative bacteria, unlike all other known carbapenemases. Here we report that membrane anchoring of -lactamases precludes detection of carbapenemase activity by the MHT. We also show that this limitation can be overcome by the addition of Triton X-100 during the test, which allows detection of NDM. We propose an improved version of the assay, called the Triton Hodge test (THT), which allows detection of membrane- bound carbapenemases with the addition of this nonionic surfactant. This test was challenged with a panel of 185 clinical isolates (145 carrying known carbapenemase-encoding genes and 40 carbapenemase nonproducers). The THT displayed test sensitivity of>90% against NDM-producing clinical isolates, while improving performance against other carbapenemases. Ertapenem provided the highest sensitivity (97 to 100%, depending on the type of carbapenemase), followed by meropenem (92.5 to 100%). Test specificity was not affected by the addition of Triton (87.5% and 92.5% with ertapenem and meropenem, respectively). This simple inexpensive test confers a large improvement to the sensitivity of the MHT for the detection of NDM and other carbapenemases. © 2016, American Society for Microbiology. All Rights Reserved.

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