Distribution of SCCmec-associated phenol-soluble modulin in staphylococci.

LENUS (Irish Health Repository)

Monecke, Stefan

2012-04-01

The recently described phenol-soluble modulin PSM-mec was detected in Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus fleuretti, Staphylococcus hominis, Staphylococcus pseudintermedius, Staphylococcus saprophyticus, Staphylococcus simulans and Staphylococcus vitulinus from different hosts (humans, goats, dogs, cats, pigs, cattle and turkeys). It was identified in isolates harbouring SCCmec types II, IIA, IIB, IID, III, VIII and in some irregular or truncated elements.

mec-associated dru typing in the epidemiological analysis of ST239 MRSA in Malaysia.

Science.gov (United States)

Ghaznavi-Rad, E; Goering, R V; Nor Shamsudin, M; Weng, P L; Sekawi, Z; Tavakol, M; van Belkum, A; Neela, V

2011-11-01

The usefulness of mec-associated dru typing in the epidemiological analysis of methicillin-resistant Staphylococcus aureus (MRSA) isolated in Malaysia was investigated and compared with pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and spa and SCCmec typing. The isolates studied included all MRSA types in Malaysia. Multilocus sequence type ST188 and ST1 isolates were highly clonal by all typing methods. However, the dru typing of ST239 isolates produced the clearest discrimination between SCCmec IIIa and III isolates, yielding more subtypes than any other method. Evaluation of the discriminatory power for each method identified dru typing and PFGE as the most discriminatory, with Simpson's index of diversity (SID) values over 89%, including an isolate which was non-typeable by spa, but dru-typed as dt13j. The discriminatory ability of dru typing, especially with closely related MRSA ST239 strains (e.g., Brazilian and Hungarian), underscores its utility as a tool for the epidemiological investigation of MRSA.

Methicillin-resistant Staphylococcus aureus in Rio de Janeiro hospitals: dissemination of the USA400/ST1 and USA800/ST5 SCCmec type IV and USA100/ST5 SCCmec type II lineages in a public institution and polyclonal presence in a private one.

Science.gov (United States)

Caboclo, Roberta Mello Ferreira; Cavalcante, Fernanda Sampaio; Iorio, Natalia Lopes Pontes; Schuenck, Ricardo Pinto; Olendzki, André Nogueira; Felix, Maria José; Chamon, Raiane Cardoso; dos Santos, Kátia Regina Netto

2013-03-01

Methicillin-resistant Staphylococcus aureus (MRSA) infections have changed since certain non-multiresistant MRSA lineages have emerged in hospitals. In this study, 99 MRSA isolates, 77 from a public and 22 from a private hospital, were characterized. Isolates were tested for antimicrobial susceptibility, whereas staphylococcal chromosomal cassette mec (SCCmec) typing and Panton-Valentine leukocidin genes were assessed by polymerase chain reaction. Pulsed-field gel electrophoresis and multilocus sequence typing analyses were carried out to determine the MRSA lineages. High rates of resistance were found to erythromycin (96%), ciprofloxacin (93%), and clindamycin (90%). The SCCmec types found were as follows: type II (14.2%), III (62.6%), and IV (23.2%). Approximately 85% of type III isolates was related to the Brazilian epidemic clone in both hospitals. For type IV isolates, 94.4% were related to both USA400/ sequence type (ST) 1 and USA800/ST5 lineages in the public hospital, whereas the USA400/ST1, USA800/ST5, USA1100/ST30, and EMRSA (Epidemic MRSA)-15/ST22 lineages were detected in the private hospital. Among the SCCmec II isolates, approximately 85% were related to the USA100/ST5 lineage. Three MRSA isolates were positive to Panton-Valentine leukocidin genes. The study showed that there was an emergence of USA400/ST1, USA800/ST5 SCCmec IV, and USA100/ST5 SCCmec II MRSA lineages in both hospitals. There was a dissemination of them in the public hospital and a polyclonal presence of the MRSA isolates in the private hospital. The spread of these lineages can be facilitated by the characteristics of the health institution. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Roles of CcrA and CcrB in Excision and Integration of Staphylococcal Cassette Chromosome mec, a Staphylococcus aureus Genomic Island▿

OpenAIRE

Wang, Lei; Archer, Gordon L.

2010-01-01

The gene encoding resistance to methicillin and other β-lactam antibiotics in staphylococci, mecA, is carried on a genomic island, SCCmec (for staphylococcal cassette chromosome mec). The chromosomal excision and integration of types I to IV SCCmec are catalyzed by the site-specific recombinases CcrA and CcrB, the genes for which are encoded on each element. We sought to identify the relative contributions of CcrA and CcrB in the excision and integration of SCCmec. Purified CcrB but not CcrA ...

Analysis of Staphylococcal cassette chromosome mec in Staphylococcus haemolyticus and Staphylococcus sciuri: identification of a novel ccr gene complex with a newly identified ccrA allotype (ccrA7).

Science.gov (United States)

Urushibara, Noriko; Paul, Shyamal Kumar; Hossain, Mohammad Akram; Kawaguchiya, Mitsuyo; Kobayashi, Nobumichi

2011-06-01

Methicillin resistance in staphylococci is conferred by the acquisition in its chromosome of the mecA gene, which is located on a mobile genetic element called staphylococcal cassette chromosome mec (SCCmec). Genetic type of SCCmec is defined by combination of mec gene complex class and cassette chromosome recombinase gene (ccr) allotype. In this study, we analyzed genetic diversity of the SCCmec in 11 Staphylococcus haemolyticus strains and a Staphylococcus sciuri strain, which were recently isolated from clinical specimens in Bangladesh. Among these strains, only two S. haemolyticus strains were proved to have the known types of SCCmec, that is, SCCmec V (class C2 mec-ccrC) and VII (class C1 mec-ccrC). Five S. haemolyticus strains were assigned two unique mec-ccr gene complexes combination; that is, class C1 mec-ccrA4B4 (four isolates) and class A mec-ccrC (one isolate). In the remaining four S. haemolyticus strains with class C1 mec, no known ccr allotypes could be detected. A single S. sciuri strain with class A mec complex carried a ccrA gene belonging to a novel allotype designated ccrA7, together with ccrB3. The ccrA7 gene in the S. sciuri strain showed 61.7%-82.7% sequence identity to the ccrA gene sequences published so far, and 75.3% identity to ccrA3, which is a component of the type 3 ccr complex (ccrA3-ccrB3) in methicillin-resistant Staphylococcus aureus. The results of the present study indicated that mec gene complex and ccr genes in coagulase-negative staphylococci are highly divergent, and distinct from those of common methicillin-resistant S. aureus. Identification of the novel ccrA7 allotype combined with ccrB3 suggested an occurrence of recombination between different ccr complexes in nature.

Determination of staphylococcal exotoxins, SCCmec types, and genetic relatedness of Staphylococcus intermedius group isolates from veterinary staff, companion animals, and hospital environments in Korea

Science.gov (United States)

Youn, Jung-Ho; Ahn, Kuk Ju; Lim, Suk-Kyung

2011-01-01

The Staphylococcus (S.) intermedius group (SIG) has been a main research subject in recent years. S. pseudintermedius causes pyoderma and otitis in companion animals as well as foodborne diseases. To prevent SIG-associated infection and disease outbreaks, identification of both staphylococcal exotoxins and staphylococcal cassette chromosome mec (SCCmec) types among SIG isolates may be helpful. In this study, it was found that a single isolate (one out of 178 SIG isolates examined) harbored the canine enterotoxin SEC gene. However, the S. intermedius exfoliative toxin gene was found in 166 SIG isolates although the S. aureus-derived exfoliative toxin genes, such as eta, etb and etd, were not detected. SCCmec typing resulted in classifying one isolate as SCCmec type IV, 41 isolates as type V (including three S. intermedius isolates), and 10 isolates as non-classifiable. Genetic relatedness of all S. pseudintermedius isolates recovered from veterinary staff, companion animals, and hospital environments was determined by pulsed-field gel electrophoresis. Strains having the same band patterns were detected in S. pseudintermedius isolates collected at 13 and 18 months, suggesting possible colonization and/or expansion of a specific S. pseudintermedius strain in a veterinary hospital. PMID:21897094

Prevalence and characterization of methicillin-resistant Staphylococcus aureus carrying mecA or mecC and methicillin-susceptible Staphylococcus aureus in dairy sheep farms in central Italy.

Science.gov (United States)

Giacinti, G; Carfora, V; Caprioli, A; Sagrafoli, D; Marri, N; Giangolini, G; Amoruso, R; Iurescia, M; Stravino, F; Dottarelli, S; Feltrin, F; Franco, A; Amatiste, S; Battisti, A

2017-10-01

Between January and May 2012, a total of 286 bulk tank milk samples from dairy sheep farms located in central Italy were tested for the presence of Staphylococcus aureus. One hundred fifty-three samples were positive for S. aureus (53.5%), with an average count of 2.53 log cfu/mL. A total of 679 S. aureus colonies were screened for methicillin resistance by the cefoxitin disk diffusion test, and 104 selected cefoxitin-susceptible isolates were also tested for their susceptibility to other antimicrobials representative of the most relevant classes active against Staphylococcus spp. by using the Kirby-Bauer disk diffusion method. Two methicillin-resistant Staphylococcus aureus (MRSA) isolates, carrying respectively the mecA and the mecC genes, were detected in 2 samples from 2 different farms (prevalence 0.7%). The mecA-positive MRSA isolate was blaZ positive, belonged to spa type t127, sequence type (ST)1, clonal complex (CC)1, carried a staphylococcal cassette chromosome mec (SCCmec) type IVa, and was phenotypically resistant to all the β-lactams tested and to erythromycin, streptomycin, kanamycin, and tetracycline. The mecC-positive MRSA isolate was negative for the chromosomally or plasmid-associated blaZ gene but positive for the blaZ allotype associated with SCCmec XI (blaZ-SCCmecXI), belonged to spa type 843, ST(CC)130, carried a SCCmec type XI, and was resistant only to β-lactams. Both MRSA were negative for the presence of specific immune-evasion and virulence genes such as those coding for the Panton-Valentine leucocidin, the toxic shock syndrome toxin 1, and the immune evasion cluster genes. Regarding the presence of the major S. aureus enterotoxin genes, the mecC-positive MRSA tested negative, whereas the ST (CC)1 mecA-positive MRSA harbored the seh gene. Among the 104 methicillin-susceptible S. aureus isolates examined for antimicrobial susceptibility, 63 (60.58%) were susceptible to all the antimicrobials tested, and 41 (39.42%) were resistant to at

A simplified multiplex PCR assay for fast and easy discrimination of globally distributed staphylococcal cassette chromosome mec types in meticillin-resistant Staphylococcus aureus

NARCIS (Netherlands)

E. Ghaznavi Rad (Ehsanollah); N.S. Mariana (Nor Shamsudin); Z. Sekawi (Zamberi); A.F. van Belkum (Alex); V. Neela (Vasanthakumari)

2010-01-01

textabstractA multiplex PCR assay was developed for the identification of major types and subtypes of staphylococcal cassette chromosome mec (SCCmec) in meticillin-resistant Staphylococcus aureus (MRSA) strains. The method uses a novel 9 valent multiplex PCR plus two primer pairs for S. aureus

Diversity of staphylococcal cassette chromosome mec structures in methicillin-resistant Staphylococcus epidermidis and Staphylococcus haemolyticus strains among outpatients from four countries.

Science.gov (United States)

Ruppé, Etienne; Barbier, François; Mesli, Yasmine; Maiga, Aminata; Cojocaru, Radu; Benkhalfat, Mokhtar; Benchouk, Samia; Hassaine, Hafida; Maiga, Ibrahim; Diallo, Amadou; Koumaré, Abdel Karim; Ouattara, Kalilou; Soumaré, Sambou; Dufourcq, Jean-Baptiste; Nareth, Chhor; Sarthou, Jean-Louis; Andremont, Antoine; Ruimy, Raymond

2009-02-01

In staphylococci, methicillin (meticillin) resistance (MR) is mediated by the acquisition of the mecA gene, which is carried on the size and composition variable staphylococcal cassette chromosome mec (SCCmec). MR has been extensively studied in Staphylococcus aureus, but little is known about MR coagulase-negative staphylococci (MR-CoNS). Here, we describe the diversity of SCCmec structures in MR-CoNS from outpatients living in countries with contrasting environments: Algeria, Mali, Moldova, and Cambodia. Their MR-CoNS nasal carriage rates were 29, 17, 11, and 31%, respectively. Ninety-six MR-CoNS strains, comprising 75 (78%) Staphylococcus epidermidis strains, 19 (20%) Staphylococcus haemolyticus strains, 1 (1%) Staphylococcus hominis strain, and 1 (1%) Staphylococcus cohnii strain, were analyzed. Eighteen different SCCmec types were observed, with 28 identified as type IV (29%), 25 as type V (26%), and 1 as type III (1%). Fifteen strains (44%) were untypeable for their SCCmec. Thirty-four percent of MR-CoNS strains contained multiple ccr copies. Type IV and V SCCmec were preferentially associated with S. epidermidis and S. haemolyticus, respectively. MR-CoNS constitute a widespread and highly diversified MR reservoir in the community.

Genetic diversity of methicillin resistant Staphylococcus aureus strains isolated from burn patients in Iran: ST239-SCCmec III/t037 emerges as the major clone.

Science.gov (United States)

Goudarzi, Mehdi; Bahramian, Mahnaz; Satarzadeh Tabrizi, Mahboobeh; Udo, Edet E; Figueiredo, Agnes Marie Sá; Fazeli, Maryam; Goudarzi, Hossein

2017-04-01

Methicillin-resistant Staphylococcus aureus (MRSA) as a major cause of infection in health care, hospital and community settings is a global health concern. The purpose of this study was to determine the antibiotic susceptibility pattern and distribution of circulating molecular types of MRSA in a burn hospital in Tehran, the capital of Iran. During a 10-month study period, 106 Staphylococcus aureus isolates were assessed. Isolates were subjected to susceptibility testing using the disk diffusion method and Polymerase Chain Reaction (PCR) for detection of mecA, fem and nuc genes. The presence of PVL and tst encoding genes were determined by PCR method. All the MRSA isolates were genotyped by multilocus sequence typing (MLST), spa typing, SCCmec typing and agr typing. The presence of mecA gene was confirmed in all the Staphylococcus aureus isolates. Antimicrobial susceptibility testing revealed a high resistance rate (90.6%) to ampicillin, tetracycline, and erythromycin. The rates of resistance to remaining antibiotics tested varied between 18.9% and 84.9%. The high- level of resistance to mupirocin was confirmed in 19.8% of MRSA strains isolated from burn patients. Multi-drug resistance was observed in 90.6% of isolates. Sixteen of the 106 MRSA isolates (15.1%) harbored PVL-encoding genes. The majority of our MRSA strains carried SCCmec III (71.7%). ST239-SCCmec III/t037 (34%) was the most common genotype followed by ST239-SCCmec III/t030 (24.5%), ST15-SCCmec IV/t084 (15.1%), ST22-SCCmec IV/t790 (13.2%), and ST239-SCCmec III/t631 (13.2%). Mupirocin resistant MRSA isolates belonged to ST15-SCCmec IV/t084 (40%), ST22-SCCmec IV/t790 (23.3%), ST239-SCCmec III/t631 (20%), and ST239-SCCmec III/t030 (16.7%) clones. The results showed that genetically diverse strains of MRSA are circulating in our burn hospitals with relatively high prevalence of ST239-SCCmec III/t037 clone. The findings support the need for regular surveillance of MRSA to determine the distribution of

A new multiplex PCR for easy screening of methicillin-resistant Staphylococcus aureus SCCmec types I-V

DEFF Research Database (Denmark)

Boye, Kit; Bartels, Mette Damkjær; Andersen, Ina S

2007-01-01

A multiplex PCR with four primer-pairs was designed to identify the five main known SCCmec types. A clear and easily discriminated band pattern was obtained for all five types. The SCCmec type was identified for 98% of 312 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA......). SCCmec type IV was by far the most common SCCmec type among both hospital- and community-acquired MRSA isolates in Denmark....

SCCmec type IX element in Methicillin resistant Staphylococcus aureus spa-type t337 (CC9 isolated from pigs and pork in Thailand

Directory of Open Access Journals (Sweden)

Martin eVestergaard

2012-03-01

Full Text Available Methicillin resistant Staphylococcus aureus (MRSA have emerged among livestock in several countries. In this study, we describe the results of a screening performed in pigs and raw pork samples in Thailand. Ten pork samples and 15 nasal swabs from pigs were collected from two markets and one pig farm in the Samuth Songkhram province in Thailand. MRSA were isolated using selective isolation procedures and confirmed by mecA PCR. The MRSA were characterized by antimicrobial susceptibility testing, PFGE, spa typing, SCCmec typing, and MLST. Resistance and virulence markers were screened using a microarray. Five of the pork samples and six pig nasal swabs were positive for MRSA. All 11 isolates belonged to spa type t337 and CC9 but showed diversity in antimicrobial resistance patterns and PFGE profiles. All isolates harbored SCCmec IX and were resistant to seven out of 14 tested antimicrobials; additional resistances were found in the pork isolates. Microarray analysis identified blaZ, aac-aphD, vga(A, tetM, and a tet efflux marker, in all strains and additionally ermB and aadD, cat and fex(A in the pork isolates. None of the isolates were found PVL-positive, but enterotoxins were identified in all isolates. This is, to our knowledge, the first description of MRSA in livestock and food products in Thailand and also the first observation of MRSA CC9 associated with SCCmec IX. This study indicates a likely widespread distribution of MRSA in pig and pork in Thailand and further investigation on the prevalence and importance of livestock associated MRSA in Thailand is needed.

Antimicrobial susceptibility pattern and SCCmec types of methicillin-resistant coagulase-negative staphylococci from subclinical bovine mastitis in Hatay, Turkey

Directory of Open Access Journals (Sweden)

Aslantaş Özkan

2014-12-01

Full Text Available Eighty-nine isolates of coagulase-negative staphylococci (CoNS of eight species from subclinical bovine mastitis were screened for the phenotypic and genotypic methicilline-resistance. In addition, all methicillin-resistant (MR isolates indicating the mecA gene were examined by PCR for the antimicrobial susceptibility patterns, and staphylococcal cassette chromosome mec (SCCmec types were also determined by multiplex PCR. A total of 21 (23.6% CoNS isolates were found to be resistant to oxacillin in broth microdilution assay. All isolates phenotypically resistant to oxacillin did not have the mecA gene, which was only found in 14.6% (13 of the isolates. Most MR-CoNS isolates were highly resistant to erythromycin (92.3%, fusidic acid (84.6%, penicillin (76.9%, and rifampycin (61.5%, and susceptible to mupirocin (100%, tetracycline (100%, vancomycin (100%, clindamycin (92.3%, and sulfamethoxazole-trimethoprim (69.2%. In conclusion, a high rate of antimicrobial resistance among MR-CoNS isolated from food producing animals emphasises the need for periodic surveillance of their resistance.

Characterization of a novel arginine catabolic mobile element (ACME) and staphylococcal chromosomal cassette mec composite island with significant homology to Staphylococcus epidermidis ACME type II in methicillin-resistant Staphylococcus aureus genotype ST22-MRSA-IV.

LENUS (Irish Health Repository)

Shore, Anna C

2011-05-01

The arginine catabolic mobile element (ACME) is prevalent among methicillin-resistant Staphylococcus aureus (MRSA) isolates of sequence type 8 (ST8) and staphylococcal chromosomal cassette mec (SCCmec) type IVa (USA300) (ST8-MRSA-IVa isolates), and evidence suggests that ACME enhances the ability of ST8-MRSA-IVa to grow and survive on its host. ACME has been identified in a small number of isolates belonging to other MRSA clones but is widespread among coagulase-negative staphylococci (CoNS). This study reports the first description of ACME in two distinct strains of the pandemic ST22-MRSA-IV clone. A total of 238 MRSA isolates recovered in Ireland between 1971 and 2008 were investigated for ACME using a DNA microarray. Twenty-three isolates (9.7%) were ACME positive, and all were either MRSA genotype ST8-MRSA-IVa (7\\/23, 30%) or MRSA genotype ST22-MRSA-IV (16\\/23, 70%). Whole-genome sequencing and comprehensive molecular characterization revealed the presence of a novel 46-kb ACME and staphylococcal chromosomal cassette mec (SCCmec) composite island (ACME\\/SCCmec-CI) in ST22-MRSA-IVh isolates (n=15). This ACME\\/SCCmec-CI consists of a 12-kb DNA region previously identified in ACME type II in S. epidermidis ATCC 12228, a truncated copy of the J1 region of SCCmec type I, and a complete SCCmec type IVh element. The composite island has a novel genetic organization, with ACME located within orfX and SCCmec located downstream of ACME. One PVL locus-positive ST22-MRSA-IVa isolate carried ACME located downstream of SCCmec type IVa, as previously described in ST8-MRSA-IVa. These results suggest that ACME has been acquired by ST22-MRSA-IV on two independent occasions. At least one of these instances may have involved horizontal transfer and recombination events between MRSA and CoNS. The presence of ACME may enhance dissemination of ST22-MRSA-IV, an already successful MRSA clone.

Multiple-locus variable number of tandem repeats fingerprinting (MLVF) and virulence factor analysis of methicillin resistant Staphylococcus aureus SCCmec type III.

Science.gov (United States)

Emaneini, Mohammad; Jabalameli, Leila; Iman-Eini, Hossein; Aligholi, Marzieh; Ghasemi, Amir; Nakhjavani, Farrokh Akbari; Taherikalani, Morovat; Khoramian, Babak; Asadollahi, Parisa; Jabalameli, Fereshteh

2011-01-01

Methicillin resistant Staphylococcus aureus (MRSA), particularly strains with type III staphylococcal cassette chromosome mec (SCCmec), represent a serious human pathogen in Tehran, Iran. The disease-causing capability depends on their ability to produce a wide variety of virulent factors. The prevalence of exotoxin genes and multiple-locus variable number of tandem repeats fingerprinting (MLVF) profile among MRSA isolates, from patients in Tehran, was evaluated by PCR and Multiplex-PCR. The MLVF typing of 144 MRSA isolates with type III SCCmec produced 5 different MLVF types. Generally, 97.2% (140/144) of all the isolates were positive for at least one of the tested exotoxin genes. The most prevalent genes were hld, found in 87.5% (126/144) of the isolates followed by lukE-lukD and hla found in 72.9% (105/144) and 70.1% (101/144) of the isolates, respectively. The tst gene, belonging to MLVF types I, IV and V, was found among three of the isolates from blood and wound samples. The sea gene was detected in 58.3% (84/144) of the isolates and the sed and see genes were found in one isolate with MLVF type V. The coexistence of genes was observed in the 87.5% (126/144) of the isolates. The rate of coexistence of hld with lukE-lukD, hla with lukE-lukD and sea with lukE-lukD were 66.7% (96/144), 44.4% (64/144) and 44.4% (64/144), respectively. The present study demonstrated that MRSA strains with type III SCCmec show different MLVF patterns and exotoxin profiles.

Excision of the Staphylococcal Cassette Chromosome mec (SCCmec) and its crucial role in the horizontal transfer of methicillin resistance in staphylococci.

OpenAIRE

Stojanov, M.

2012-01-01

Staphylococcus aureus est un pathogène humain majeur ayant développé des résistances contre la quasi totalité des antibiotiques disponibles, incluant la très importante famille des β- lactamines. La résistance à cette classe d'antibiotiques est conférée par la « Staphylococcal Cassette Chromosome mec » (SCCmec), qui est un élément génétique mobile capable de s'insérer dans le chromosome bactérien et capable d'être transféré horizontalement chez d'autres staphylocoques. Le mécanisme moléculair...

An Improved MLVF Method and Its Comparison with Traditional MLVF, spa Typing, MLST/SCCmec and PFGE for the Typing of Methicillin-Resistant Staphylococcus aureus

Science.gov (United States)

Du, Xue-Fei; Xiao, Meng; Liang, Hong-Yan; Sun, Zhe; Jiang, Yue-Hong; Chen, Guo-Yu; Meng, Xiao-Yu; Zou, Gui-Ling; Zhang, Li; Liu, Ya-Li; Zhang, Hui; Sun, Hong-Li; Jiang, Xiao-Feng; Xu, Ying-Chun

2014-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) has become an important nosocomial pathogen, causing considerable morbidity and mortality. During the last 20 years, a variety of genotyping methods have been introduced for screening the prevalence of MRSA. In this study, we developed and evaluated an improved approach capillary gel electrophoresis based multilocus variable-number tandem-repeat fingerprinting (CGE/MLVF) for rapid MRSA typing. A total of 42 well-characterized strains and 116 non-repetitive clinical MRSA isolates collected from six hospitals in northeast China between 2009 and 2010 were tested. The results obtained by CGE/MLVF against clinical isolates were compared with traditional MLVF, spa typing, Multilocus sequence typing/staphylococcal cassette chromosome mec (MLST/SCCmec) and pulse field gel electrophoresis (PFGE). The discriminatory power estimated by Simpson’s index of diversity was 0.855 (28 types), 0.855 (28 patterns), 0.623 (11 types), 0.517 (8 types) and 0.854 (28 patterns) for CGE/MLVF, traditional MLVF, spa typing, MLST/SCCmec and PFGE, respectively. All methods tested showed a satisfied concordance in clonal complex level calculated by adjusted Rand’s coefficient. CGE/MLVF showed better reproducibility and accuracy than traditional MLVF and PFGE methods. In addition, the CGE/MLVF has potential to produce portable results. In conclusion, CGE/MLVF is a rapid and easy to use MRSA typing method with lower cost, good reproducibility and high discriminatory power for monitoring the outbreak and clonal spread of MRSA isolates. PMID:24406728

CC8 MRSA strains harboring SCCmec type IVc are predominant in Colombian hospitals.

Directory of Open Access Journals (Sweden)

J Natalia Jiménez

Full Text Available BACKGROUND: Recent reports highlight the incursion of community-associated MRSA within healthcare settings. However, knowledge of this phenomenon remains limited in Latin America. The aim of this study was to evaluate the molecular epidemiology of MRSA in three tertiary-care hospitals in Medellín, Colombia. METHODS: An observational cross-sectional study was conducted from 2008-2010. MRSA infections were classified as either community-associated (CA-MRSA or healthcare-associated (HA-MRSA, with HA-MRSA further classified as hospital-onset (HAHO-MRSA or community-onset (HACO-MRSA according to standard epidemiological definitions established by the U.S. Centers for Disease Control and Prevention (CDC. Genotypic analysis included SCCmec typing, spa typing, PFGE and MLST. RESULTS: Out of 538 total MRSA isolates, 68 (12.6% were defined as CA-MRSA, 243 (45.2% as HACO-MRSA and 227 (42.2% as HAHO-MRSA. The majority harbored SCCmec type IVc (306, 58.7%, followed by SCCmec type I (174, 33.4%. The prevalence of type IVc among CA-, HACO- and HAHO-MRSA isolates was 92.4%, 65.1% and 43.6%, respectively. From 2008 to 2010, the prevalence of type IVc-bearing strains increased significantly, from 50.0% to 68.2% (p = 0.004. Strains harboring SCCmec IVc were mainly associated with spa types t1610, t008 and t024 (MLST clonal complex 8, while PFGE confirmed that the t008 and t1610 strains were closely related to the USA300-0114 CA-MRSA clone. Notably, strains belonging to these three spa types exhibited high levels of tetracycline resistance (45.9%. CONCLUSION: CC8 MRSA strains harboring SCCmec type IVc are becoming predominant in Medellín hospitals, displacing previously reported CC5 HA-MRSA clones. Based on shared characteristics including SCCmec IVc, absence of the ACME element and tetracycline resistance, the USA300-related isolates in this study are most likely related to USA300-LV, the recently-described 'Latin American variant' of USA300.

Diversity of staphylococcal cassette chromosome mec structures in coagulase-negative staphylococci and relationship to drug resistance.

Science.gov (United States)

Garza-González, Elvira; López, Daniel; Pezina, Cesar; Muruet, Walter; Bocanegra-García, Virgilio; Muñoz, Ivan; Ramírez, Camilo; Llaca-Díaz, Jorge M

2010-03-01

The objective of this study was to determine the distribution of staphylococcal cassette chromosome mec (SCCmec) elements in meticillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from a tertiary-care hospital in Mexico and to examine the relationship to drug resistance. Fifty selected MR-CoNS isolates collected from catheters (n=15), blood (n=15), bone (n=9), bronchial lavage (n=2) and urine (n=2) and one isolate each from an abscess, cerebrospinal fluid, eye, pleural effusion, synovial fluid, tracheal aspirate and wound secretion were examined. Susceptibility testing was performed by the broth microdilution method. SCCmec types were determined by multiplex PCR and PFGE was carried out as described previously for Staphylococcus aureus. Among the MR-CoNS strains studied, the most frequently isolated species were Staphylococcus epidermidis (n=26) and Staphylococcus haemolyticus (n=13). Staphylococcus cohnii (n=5), Staphylococcus hominis (n=3), Staphylococcus sciuri (n=1), Staphylococcus pasteuri (n=1) and the recently described species Staphylococcus pettenkoferi (n=1) were also identified. The most frequent MR-CoNS genotype identified was SCCmec type IVa in S. epidermidis isolates, which also showed a high diversity in their PFGE patterns. A clone was found that amplified both SCCmec III and V elements in five isolates examined. The single MR S. pettenkoferi isolate harboured SCCmec type IVd and the single MR S. pasteuri isolate harboured SCCmec type I. The carriage of SCCmec type III was associated with resistance or intermediate resistance to meropenem (P <0.05). These results confirm the high prevalence of S. epidermidis SCCmec IVa and the high genetic diversity among MR-CoNS strains. As far as is known, this is the first report describing the newly identified S. pettenkoferi possessing SCCmec IVd and S. pasteuri harbouring SCCmec type I. MR-CoNS harbouring SCCmec type III were found to be more resistant to meropenem.

Methicillin-resistant Staphylococcus aureus isolates with SCCmec type V and spa types t437 or t1081 associated to discordant susceptibility results between oxacillin and cefoxitin, Central Taiwan.

Science.gov (United States)

Ho, Cheng-Mao; Lin, Chien-Yu; Ho, Mao-Wang; Lin, Hsiao-Chuan; Chen, Chao-Jung; Lin, Lee-Chung; Lu, Jang-Jih

2016-12-01

Staphylococcus aureus isolates with discordant susceptibility results between oxacillin and cefoxitin obtained using automated microbiology systems are infrequently observed. From April 2013 to December 2014, 1956 methicillin-resistant S. aureus (MRSA) and 1761 methicillin-susceptible S. aureus isolates were obtained from different patients. Forty isolates (1.1% and 2% in case of S. aureus and MRSA, respectively) with discordant susceptibility results (oxacillin susceptible and cefoxitin resistant) and carrying mecA gene were obtained. Except 2 SCCmec type IV isolates, 38 MRSA isolates were all SCCmec type V (V T or non-V T ), which were further divided into V T (n=22) and non-V T (n=16). The most common spa type in V T and non-V T isolates were t437 (n=19) and t1081 (n=13), respectively. Only 55% of patients received effective antimicrobial agents; 2 mortalities were not attributable to MRSA infection. Using standard agar dilution, 17 MRSA isolates (0.46% and 0.87% in case of S. aureus and MRSA, respectively) had oxacillin MIC in the susceptible ranges (oxacillin-susceptible MRSA [OS-MRSA]); all carried SCCmec type V (V T , n=8; non-V T , n=9). The most common spa-MLST types of OS-MRSA in V T and non-V T were t437-ST59 (n=4) and t1081-ST45 (n=7), respectively. Concomitant testing by both cefoxitin- and oxacillin-based methods is a practical strategy for OS-MRSA detection in the clinical laboratories. Continuous monitoring of OS-MRSA isolates is necessary to elucidate their impact in clinical infectious diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

A new multiplex PCR for easy screening of methicillin-resistant Staphylococcus aureus SCCmec types I-V

DEFF Research Database (Denmark)

Boye, Kit; Bartels, Mette Damkjær; Andersen, Ina S

2007-01-01

A multiplex PCR with four primer-pairs was designed to identify the five main known SCCmec types. A clear and easily discriminated band pattern was obtained for all five types. The SCCmec type was identified for 98% of 312 clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA...

Predominant Dissemination of PVL-Negative CC89 MRSA with SCCmec Type II in Children with Impetigo in Japan

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H. Kikuta

2011-01-01

Full Text Available Background. The ratio of CA-MRSA in children with impetigo has been increasing in Japan. Methods. Antimicrobial susceptibilities of 136 S. aureus isolates from children with impetigo were studied. Furthermore, molecular epidemiological analysis and virulence gene analysis were performed. Results. Of the 136 S. aureus isolates, 122 (89.7% were MSSA and 14 (10.3% were MRSA. Of the 14 MRSA strains, 11 belonged to CC89 (ST89, ST91, and ST2117 and carried diverse types of SCCmec: type II (IIb: 3 strains; unknown subtype: 4 strains, type IVa (2 strains, and unknown type (2 strains. The remaining three strains exhibited CC8 (ST-8-SCCmec type VIa, CC121 (ST121-SCCmec type V, and CC5 (ST5-nontypeable SCCmec element, respectively. None were lukS-PV-lukF-PV gene positive. Gentamicin- and clarithromycin-resistant strains were frequently found in both MRSA and MSSA. Conclusions. PVL-negative CC89-SCCmec type II strains are the most predominant strains among the CA-MRSA strains circulating in the community in Japan.

Tetracycline and trimethoprim/sulfamethoxazole at clinical laboratory: can they help to characterize Staphylococcus aureus carrying different SCCmec types?

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Cavalcante, Fernanda Sampaio; Schuenck, Ricardo Pinto; Caboclo, Roberta Mello Ferreira; Ferreira, Dennis de Carvalho; Nouér, Simone Aranha; Santos, Kátia Regina Netto dos

2013-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) can be difficult to detect at the clinical practice. We analyzed 140 MRSA isolates from inpatients to correlate the antimicrobial susceptibility with the SCCmec types. Type III (n = 63) isolates were more resistant to ciprofloxacin, clindamycin, cloramphenicol, erythromycin, gentamicin, and rifampin than type IV (n = 65) ones (p < 0.05). Moreover, type IV isolates were susceptible to tetracycline (100%) and trimethoprim/sulfamethoxazole (98%), while type III isolates presented resistance to them. In regions where these SCCmec types are prevalent, the detection of specific resistant phenotypes could help to predict them, mainly when there are no technical conditions to SCCmec typing.

Fine typing of methicillin-resistant Staphylococcus aureus isolates using direct repeat unit and staphylococcal interspersed repeat unit typing methods.

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Ho, Cheng-Mao; Ho, Mao-Wang; Li, Chi-Yuan; Lu, Jang-Jih

2015-08-01

Methicillin-resistant Staphylococcus aureus (MRSA) typing is an important epidemiologic tool for monitoring trends and preventing outbreaks. However, the efficiency of various MRSA typing methods for each SCCmec MRSA isolate is rarely evaluated. A total of 157 MRSA isolates from four different regions in Taiwan were typed with five different molecular methods, including SCCmec typing, multilocus sequence typing (MLST), spa typing, mec-associated direct repeat unit (dru) copy number determination, and staphylococcal interspersed repeat unit (SIRU) profiling. There were four SCCmec types, eight MLST types, 15 spa types, 11 dru types, and 31 SIRU profiles. The most common type determined by each molecular typing method was SCCmec III (115 isolates, 73.2%), ST239 (99 isolates, 63.1%), t037 (107 isolates, 68.2%), 14 dru copies (76 isolates, 48.4%), and SIRU profile 3013722 (102 isolates, 65%), respectively. When using the combination of MLST, spa typing, and dru copy number, ST5-t002-4 (n = 8), ST239-t037-14 (n = 68), ST59-t437-9 (n = 9), and ST59-t437-11 (n = 6) were found to be the most common types of SCCmec types II (n = 9), III (n = 115), IV (n = 21), and VT (n = 11) isolates, respectively. SCCmec type III isolates were further classified into 11 dru types. Of the 21 SCCmec type IV isolates, 14 SIRU profiles were found. Seven SIRU patterns were observed in the 11 SCCmec type VT isolates. Different typing methods showed a similar Hunter-Gaston discrimination index among the 157 MRSA isolates. However, dru and SIRU typing methods had a better discriminatory power for SCCmec type III and SCCmec types IV and VT isolates, respectively, suggesting that dru and SIRU can be used to further type these isolates. Copyright © 2013. Published by Elsevier B.V.

Evolutionary Origin of the Staphylococcal Cassette Chromosome mec (SCCmec)

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Rolo, Joana; Worning, Peder; Nielsen, Jesper Boye

2017-01-01

, many steps are still missing from this evolutionary history. In particular, it is not known how mecA was incorporated into the mobile element SCC prior to dissemination among Staphylococcus aureus and other pathogenic staphylococcal species. To gain insights into the possible contribution of several...

Spreading of genes encoding enterotoxins, haemolysins, adhesin and biofilm among methicillin resistant Staphylococcus aureus strains with staphylococcal cassette chromosome mec type IIIA isolated from burn patients.

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Motallebi, Mitra; Jabalameli, Fereshteh; Asadollahi, Kheirollah; Taherikalani, Morovat; Emaneini, Mohammad

2016-08-01

The emergence of antibiotic-resistant Staphylococcus aureus in particular methicillin-resistant S. aureus (MRSA) is an important concern in burn medical centers either in Iran or worldwide. A total of 128 S. aureus isolates were collected from wound infection of burn patients during June 2013 to June 2014. Multiplex-polymerase chain reaction (MPCR) assay was performed for the characterization of the staphylococcal cassette chromosome mec (SCCmec). Genes encoding virulence factors and biofilm were targeted by PCR. Of 128 S. aureus isolates, 77 (60.1%) isolates were MRSA. Fifty four (70.1%) isolates were identified as SCCmec type IIIA. The most frequently detected toxin genes among MRSA isolates with SCCmec type IIIA were sea (64.1%) and hla (51.8%). The rate of coexistence of sea with hla and sea with hla and hlb was 37% and12.9%, respectively. The sec, eta, tst, pvl, hla and hlb genes were not detected in any of the MRSA isolates. The most prevalent genes encoding biofilm was eno, found in 61.1% of isolates, followed by fib and icaA found in 48.1% and 38.8% of the isolates, respectively. The rate of coexistence of fib + eno + icaA + icaD and fib + eno was 20.3% and 9.2%, respectively. The ebps gene was not detected in any of the isolates. In conclusion, our study indicated that the sea, hla, fib and icaA were most frequent genes encoding virulence factors among MRSA with SCCmec type IIIA isolated from burn wound infection. Moreover, the results of this study shows that the rate of coexistence of genes encoding different virulence factor were high. Copyright © 2016 Elsevier Ltd. All rights reserved.

Methicillin-resistant Staphylococcus aureus carrying SCCmec type II was more frequent than the Brazilian endemic clone as a cause of nosocomial bacteremia.

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Caiaffa-Filho, Helio Hehl; Trindade, Priscila A; Gabriela da Cunha, Paula; Alencar, Cecilia Salete; Prado, Gladys V B; Rossi, Flavia; Levin, Anna S

2013-08-01

Fifty consecutive MRSA blood isolates were evaluated: 30(60%) carried SCCmec type II (single PFGE clone; sequence type 5 or ST105); 12 (26%), IV; 5 (10%), III; 3 (6%), I. Brazilian endemic clone, carrying SCCmec type III, has been the main nosocomial clone in Brazil; however, this study showed that a clone carrying type II predominated. Copyright © 2013 Elsevier Inc. All rights reserved.

Recombinations in staphylococcal cassette chromosome mec elements compromise the molecular detection of methicillin resistance in Staphylococcus aureus

KAUST Repository

Hill-Cawthorne, Grant A.

2014-06-27

Clinical laboratories are increasingly using molecular tests for methicillin-resistant Staphylococcus aureus (MRSA) screening. However, primers have to be targeted to a variable chromosomal region, the staphylococcal cassette chromosome mec (SCCmec). We initially screened 726 MRSA isolates from a single UK hospital trust by recombinase polymerase amplification (RPA), a novel, isothermal alternative to PCR. Undetected isolates were further characterised using multilocus sequence, spa typing and whole genome sequencing. 96% of our tested phenotypically MRSA isolates contained one of the six orfX-SCCmec junctions our RPA test and commercially available molecular tests target. However 30 isolates could not be detected. Sequencing of 24 of these isolates demonstrated recombinations within the SCCmec element with novel insertions that interfered with the RPA, preventing identification as MRSA. This result suggests that clinical laboratories cannot rely solely upon molecular assays to reliably detect all methicillin-resistance. The presence of significant recombinations in the SCCmec element, where the majority of assays target their primers, suggests that there will continue to be isolates that escape identification. We caution that dependence on amplification-based molecular assays will continue to result in failure to diagnose a small proportion (?4%) of MRSA isolates, unless the true level of SCCmec natural diversity is determined by whole genome sequencing of a large collection of MRSA isolates. © 2014 Hill-Cawthorne et al.

Recombinations in staphylococcal cassette chromosome mec elements compromise the molecular detection of methicillin resistance in Staphylococcus aureus.

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Grant A Hill-Cawthorne

Full Text Available Clinical laboratories are increasingly using molecular tests for methicillin-resistant Staphylococcus aureus (MRSA screening. However, primers have to be targeted to a variable chromosomal region, the staphylococcal cassette chromosome mec (SCCmec. We initially screened 726 MRSA isolates from a single UK hospital trust by recombinase polymerase amplification (RPA, a novel, isothermal alternative to PCR. Undetected isolates were further characterised using multilocus sequence, spa typing and whole genome sequencing. 96% of our tested phenotypically MRSA isolates contained one of the six orfX-SCCmec junctions our RPA test and commercially available molecular tests target. However 30 isolates could not be detected. Sequencing of 24 of these isolates demonstrated recombinations within the SCCmec element with novel insertions that interfered with the RPA, preventing identification as MRSA. This result suggests that clinical laboratories cannot rely solely upon molecular assays to reliably detect all methicillin-resistance. The presence of significant recombinations in the SCCmec element, where the majority of assays target their primers, suggests that there will continue to be isolates that escape identification. We caution that dependence on amplification-based molecular assays will continue to result in failure to diagnose a small proportion (∼4% of MRSA isolates, unless the true level of SCCmec natural diversity is determined by whole genome sequencing of a large collection of MRSA isolates.

Recombinations in staphylococcal cassette chromosome mec elements compromise the molecular detection of methicillin resistance in Staphylococcus aureus

KAUST Repository

Hill-Cawthorne, Grant A.; Hudson, Lyndsey O.; Abd El Ghany, Moataz; Piepenburg, Olaf; Nair, Mridul; Dodgson, Andrew; Forrest, Matthew S.; Clark, Taane G.; Pain, Arnab

2014-01-01

Clinical laboratories are increasingly using molecular tests for methicillin-resistant Staphylococcus aureus (MRSA) screening. However, primers have to be targeted to a variable chromosomal region, the staphylococcal cassette chromosome mec (SCCmec). We initially screened 726 MRSA isolates from a single UK hospital trust by recombinase polymerase amplification (RPA), a novel, isothermal alternative to PCR. Undetected isolates were further characterised using multilocus sequence, spa typing and whole genome sequencing. 96% of our tested phenotypically MRSA isolates contained one of the six orfX-SCCmec junctions our RPA test and commercially available molecular tests target. However 30 isolates could not be detected. Sequencing of 24 of these isolates demonstrated recombinations within the SCCmec element with novel insertions that interfered with the RPA, preventing identification as MRSA. This result suggests that clinical laboratories cannot rely solely upon molecular assays to reliably detect all methicillin-resistance. The presence of significant recombinations in the SCCmec element, where the majority of assays target their primers, suggests that there will continue to be isolates that escape identification. We caution that dependence on amplification-based molecular assays will continue to result in failure to diagnose a small proportion (?4%) of MRSA isolates, unless the true level of SCCmec natural diversity is determined by whole genome sequencing of a large collection of MRSA isolates. © 2014 Hill-Cawthorne et al.

Rapid detection, differentiation and typing of methicillin-resistant Staphylococcus aureus harbouring either mecA or the new mecA homologue mecA(LGA251).

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Stegger, M; Andersen, P S; Kearns, A; Pichon, B; Holmes, M A; Edwards, G; Laurent, F; Teale, C; Skov, R; Larsen, A R

2012-04-01

The recent finding of a new mecA homologue, mecA(LGA251) , with only 70% nucleotide homology to the conventional mecA gene has brought the routine testing for mecA as a confirmatory test for methicillin-resistant Staphylococcus aureus (MRSA) into question. A multiplex PCR was designed to differentiate mecA(LGA251) from the known mecA together with detection of lukF-PV and the spa gene fragments, enabling direct spa typing by sequencing of the PCR amplicons. The PCR analysis and subsequent spa typing were validated on a large collection (n=185) of contemporary MRSA and methicillin-sensitive S. aureus isolates, including 127 isolates carrying mecA(LGA251) . The mecA(LGA251) gene was situated in staphylococcal cassette chromosome mec type XI elements, and sequence variation within a 631-bp fragment of mecA(LGA251) in 79 isolates indicated a very conserved gene sequence. Following a successful validation, the multiplex PCR strategy was implemented in the routine testing of MRSA for national surveillance. Over a 2-month period, among 203 samples tested, 12 new MRSA cases caused by isolates carrying mecA(LGA251) were identified, emphasizing the clinical importance of testing for these new MRSA isolates. © 2011 STATENS SERUM INSTITUT. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.

Antibiotic resistance and mecA characterization of coagulase-negative staphylococci isolated from three hotels in London, UK

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Zhen eXu

2015-09-01

Full Text Available Antibiotic resistance in bacteria isolated from non–healthcare environments, is a potential problem to public health. In our survey a total of 71 coagulase negative staphylococci belonging to 11 different species were isolated from 3 large hotels in London, UK. The most prevalent species was Staphylococcus haemolyticus, with S. hominis, S. warneri, S.cohnii and S. epidermidis commonly detected. Antimicrobial susceptibilities and carriage of the mecA gene were determined for all of these isolates. Most (85.9% staphylococci were resistant to multiple antibiotics with all displaying increased susceptibility towards penicillin, fusidic acid, erythromycin and cefepime. 21 (29.5% of the isolates were mecA positive, however MIC values to oxacillin, normally associated with the carriage of mecA, varied widely in this group (from 0.06 mg/L to 256 mg/L. 15 of the 21 mecA positive isolates carried SCCmec of these 7 were type V, 1 type I, 1 type II and 1 type IV. Additionally, five of these 15 isolates carried a previously unreported type, 1A, which involves an association between class A mec complex and ccr type 1. The remaining 6 of the 21 isolates were non-typeable and carried a combination of class A mec complex and ccrC. In addition to this, we also report on new MLST types which were assigned for 5 Staphylococcus epidermidis isolates. 4 out of these 5 isolates had MICs between 0.06 to 256 mg/L to oxacillin and would be regarded as clinically susceptible but one isolate had a high oxacillin MIC of 256 mg/L. We demonstrated widespread multiple drug resistance among different staphylococcal species isolated from non-healthcare environments highlighting the potential for these species to act as a reservoir for methicillin and other forms of drug resistance.

Antibiotic resistance and mecA characterization of coagulase-negative staphylococci isolated from three hotels in London, UK.

Science.gov (United States)

Xu, Zhen; Mkrtchyan, Hermine V; Cutler, Ronald R

2015-01-01

Antibiotic resistance in bacteria isolated from non-healthcare environments, is a potential problem to public health. In our survey a total of 71 coagulase negative staphylococci (CNS) belonging to 11 different species were isolated from three large hotels in London, UK. The most prevalent species was Staphylococcus haemolyticus, with S. hominis, S. warneri, S. cohnii, and Staphylococcus epidermidis commonly detected. Antimicrobial susceptibilities and carriage of the mecA gene were determined for all of these isolates. Most (85.9%) staphylococci were resistant to multiple antibiotics with all displaying increased susceptibility toward penicillin, fusidic acid, erythromycin, and cefepime. Twenty-one (29.5%) of the isolates were mecA positive, however MIC values to oxacillin, normally associated with the carriage of mecA, varied widely in this group (from 0.06 to 256 mg/L). Fifteen of the twenty-one mecA positive isolates carried SCCmec of these seven were type V, one type I, one type II, and one type IV. Additionally, five of these 15 isolates carried a previously unreported type, 1A, which involves an association between class A mec complex and ccr type 1. The remaining six of the 21 isolates were non-typeable and carried a combination of class A mec complex and ccrC. In addition to this, we also report on new MLST types which were assigned for five S. epidermidis isolates. Four out of these five isolates had MICs between 0.06 and 256 mg/L to oxacillin and would be regarded as clinically susceptible but one isolate had a high oxacillin MIC of 256 mg/L. We demonstrated widespread multiple drug resistance among different staphylococcal species isolated from non-healthcare environments highlighting the potential for these species to act as a reservoir for methicillin and other forms of drug resistance.

Old Drugs To Treat Resistant Bugs: Methicillin-Resistant Staphylococcus aureus Isolates with mecC Are Susceptible to a Combination of Penicillin and Clavulanic Acid.

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Ba, Xiaoliang; Harrison, Ewan M; Lovering, Andrew L; Gleadall, Nicholas; Zadoks, Ruth; Parkhill, Julian; Peacock, Sharon J; Holden, Matthew T G; Paterson, Gavin K; Holmes, Mark A

2015-12-01

β-Lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is mediated by the expression of an alternative penicillin-binding protein 2a (PBP2a) (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA, known as mecC, was identified in MRSA isolates from both humans and animals. In this study, we demonstrate that mecC-encoded PBP2c does not mediate resistance to penicillin. Rather, broad-spectrum β-lactam resistance in MRSA strains carrying mecC (mecC-MRSA strains) is mediated by a combination of both PBP2c and the distinct β-lactamase encoded by the blaZ gene of strain LGA251 (blaZLGA251), which is part of mecC-encoding staphylococcal cassette chromosome mec (SCCmec) type XI. We further demonstrate that mecC-MRSA strains are susceptible to the combination of penicillin and the β-lactam inhibitor clavulanic acid in vitro and that the same combination is effective in vivo for the treatment of experimental mecC-MRSA infection in wax moth larvae. Thus, we demonstrate how the distinct biological differences between mecA- and mecC-encoded PBP2a and PBP2c have the potential to be exploited as a novel approach for the treatment of mecC-MRSA infections. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Zinc resistance within swine associated methicillin resistant Staphylococcus aureus (MRSA) isolates in the USA is associated with MLST lineage

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Zinc resistance in livestock-associated methicillin resistant Staphylococcus aureus (LA-MRSA) is mediated by the czrC gene co-located with the mecA gene, encoding methicillin resistance, on the type V SCCmec element. Since the czrC gene and the mecA gene are co-located on the SCCmec element, it has ...

CPRMethicillin resistant coagulase-negative staphylococci isolated from South Korean ducks exhibiting tremor.

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Han, Jee Eun; Hwang, Sun Young; Kim, Ji Hyung; Shin, Sang Phil; Jun, Jin Woo; Chai, Ji Young; Park, Yong Ho; Park, Se Chang

2013-12-11

We describe coagulase-negative staphylococci (CoNS) isolates collected from ducklings exhibiting tremor in South Korea over the period of 2010 to 2011. Screening of antimicrobial susceptibility and analysis of SCCmec elements of CoNS were also investigated. Staphylococcus cohnii was the most frequent staphylococcus (9 isolates) and S. sciuri (4 isolates), S. lentus (3 isolate), S. simulans (1 isolate) and S. epidermidis (1 isolate) were also detected. Among the 15 antimicrobials tested in this study, resistance against oxacillin (15 isolates, 83.3%) was most frequently observed, but only one isolate (SNUDS-1) possessed mecA. This isolate was shown to possess SCCmec type III; the type 3 ccr complex and the class A mec complex. Based on these results, isolate SNUDS-1 was shown to possess SCCmec type III; the type 3 ccr complex and the class A mec complex. Although the SCCmec type III is not predominant in human, MR-CoNS (Methicillin resistance Coagulase-negative staphylococci) in food animals should be monitored to prevent the dissemination of antimicrobial resistance genes and resistant pathogens to the community.

Genome-wide analysis of the regulatory function mediated by the small regulatory psm-mec RNA of methicillin-resistant Staphylococcus aureus.

Science.gov (United States)

Cheung, Gordon Y C; Villaruz, Amer E; Joo, Hwang-Soo; Duong, Anthony C; Yeh, Anthony J; Nguyen, Thuan H; Sturdevant, Daniel E; Queck, S Y; Otto, M

2014-07-01

Several methicillin resistance (SCCmec) clusters characteristic of hospital-associated methicillin-resistant Staphylococcus aureus (MRSA) strains harbor the psm-mec locus. In addition to encoding the cytolysin, phenol-soluble modulin (PSM)-mec, this locus has been attributed gene regulatory functions. Here we employed genome-wide transcriptional profiling to define the regulatory function of the psm-mec locus. The immune evasion factor protein A emerged as the primary conserved and strongly regulated target of psm-mec, an effect we show is mediated by the psm-mec RNA. Furthermore, the psm-mec locus exerted regulatory effects that were more moderate in extent. For example, expression of PSM-mec limited expression of mecA, thereby decreasing methicillin resistance. Our study shows that the psm-mec locus has a rare dual regulatory RNA and encoded cytolysin function. Furthermore, our findings reveal a specific mechanism underscoring the recently emerging concept that S. aureus strains balance pronounced virulence and high expression of antibiotic resistance. Published by Elsevier GmbH.

A Look into the Melting Pot: The mecC-Harboring Region Is a Recombination Hot Spot in Staphylococcus stepanovicii.

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Torsten Semmler

Full Text Available Horizontal gene transfer (HGT is an important driver for resistance- and virulence factor accumulation in pathogenic bacteria such as Staphylococcus aureus.Here, we have investigated the downstream region of the bacterial chromosomal attachment site (attB for the staphylococcal cassette chromosome mec (SCCmec element of a commensal mecC-positive Staphylococcus stepanovicii strain (IMT28705; ODD4 with respect to genetic composition and indications of HGT. S. stepanovicii IMT28705 was isolated from a fecal sample of a trapped wild bank vole (Myodes glareolus during a screening study (National Network on "Rodent-Borne Pathogens" in Germany. Whole genome sequencing (WGS of IMT28705 together with the mecC-negative type strain CM7717 was conducted in order to comparatively investigate the genomic region downstream of attB (GenBank accession no. KR732654 and KR732653.The bank vole isolate (IMT28705 harbors a mecC gene which shares 99.2% nucleotide (and 98.5% amino acid sequence identity with mecC of MRSA_LGA251. In addition, the mecC-encoding region harbors the typical blaZ-mecC-mecR1-mecI structure, corresponding with the class E mec complex. While the sequences downstream of attB in both S. stepanovicii isolates (IMT28705 and CM7717 are partitioned by 15 bp direct repeats, further comparison revealed a remarkable low concordance of gene content, indicating a chromosomal "hot spot" for foreign DNA integration and exchange.Our data highlight the necessity for further research on transmission routes of resistance encoding factors from the environmental and wildlife resistome.

High incidence of oxacillin-susceptible mecA-positive Staphylococcus aureus (OS-MRSA associated with bovine mastitis in China.

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WanXia Pu

Full Text Available Staphylococcus aureus is a main cause of bovine mastitis and a major pathogen affecting human health. The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA has become a significant concern for both animal health and public health. This study investigated the incidence of MRSA in milk samples collected from dairy cows with clinical mastitis and characterized the MRSA isolates using antimicrobial susceptibility tests and genetic typing methods. In total, 103 S. aureus isolates were obtained from dairy farms in 4 different provinces in China, including Gansu, Shanghai, Sichuan, and Guizhou. Antimicrobial susceptibility testing of these isolates revealed that the resistance rates to penicillin and sulfamethoxazole were high, while the resistance rates to ciprofloxacin and vancomycin were low. Among the 103 isolates, 49 (47.6% were found to be mecA-positive, indicating the high incidence of MRSA. However, 37 of the 49 mecA-positive isolates were susceptible to oxacillin as determined by antimicrobial susceptibility assays and were thus classified as oxacillin-susceptible mecA-positive S. aureus (OS-MRSA. These isolates could be misclassified as methicillin susceptible Staphylococcus aureus (MSSA if genetic detection of mecA was not performed. Molecular characterization of selected mecA-positive isolates showed that they were all negative with Panton-Valentine leukocidin (PVL, but belonged to different spa types and SCCmec types. These results indicate that OS-MRSA is common in bovine mastitis in China and underscore the need for genetic methods (in addition to phenotypic tests to accurately identify MRSA.

An investigation of resistance to β-lactam antimicrobials among staphylococci isolated from pigs with exudative epidermitis.

Science.gov (United States)

Park, Jeonghwa; Friendship, Robert M; Weese, J Scott; Poljak, Zvonimir; Dewey, Cate E

2013-10-17

A high proportion of staphylococci isolated from pigs affected with exudative epidermitis were found to be resistant to β-lactam antimicrobials. The primary objective of this research was to investigate and characterize β-lactam resistance in Staphylococcus hyicus, Staphylococcus aureus and other staphylococci isolated from these pigs. The antimicrobial resistance patterns of 240 staphylococci isolates were determined by disk diffusion, of which 176 (73.3%) of the isolates were resistant to 3 β-lactams (penicillin G, ampicillin, and ceftiofur). The presence of mecA gene was identified in 63 staphylococci isolates from skin samples by PCR. The mecA gene was identified in 19 S. aureus, 31 S. hyicus, 9 Staphylococcus chromogenes, 2 Staphylococcus pseudintermedius isolates, and in 1 isolate each of Staphylococcus arlettae, and Staphylococcus cohnii subspecies urealyticus. From SCCmec typing results, the majority (45/63, 71.4%) were shown to be SCCmec type V. One isolate was SCCmec III. Fourteen isolates were detected as mec class A, mec class C or ccr type 5. The ccr complex and mec complex was not detected in 3 isolates of methicillin resistant S. hyicus (MRSH) based on multiplex PCR. Of the 30 isolates of MRSA identified from nasal samples of the pigs, 29 isolates were SCCmec type V and 1 isolate was SCCmec type II. Staphyloccoci isolates that were mecA negative but resistant to β-lactam antimicrobials were further examined by screening for mecC, however all were negative. Furthermore, the majority of mecA negative β-lactam resistant staphylococci isolates were susceptible to oxacillin and amoxicillin-clavulanic acid in a double disk diffusion test. Methicillin resistance can be identified in a variety of staphylococcal species isolated from pigs. In this study there was a great deal of similarity in the SCCmec types between staphylococcal species, suggesting that resistance may be passed from one species of staphylococci to another species of staphylococci

Microbiological and molecular characterization of Staphylococcus hominis isolates from blood.

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Soraya Mendoza-Olazarán

Full Text Available BACKGROUND: Among Coagulase-Negative Staphylococci (CoNS, Staphylococcus hominis represents the third most common organism recoverable from the blood of immunocompromised patients. The aim of this study was to characterize biofilm formation, antibiotic resistance, define the SCCmec (Staphylococcal Chromosomal Cassette mec type, and genetic relatedness of clinical S. hominis isolates. METHODOLOGY: S. hominis blood isolates (n = 21 were screened for biofilm formation using crystal violet staining. Methicillin resistance was evaluated using the cefoxitin disk test and the mecA gene was detected by PCR. Antibiotic resistance was determined by the broth microdilution method. Genetic relatedness was determined by pulsed-field gel electrophoresis (PFGE and SCCmec typed by multiplex PCR using two different methodologies described for Staphylococcus aureus. RESULTS: Of the S. hominis isolates screened, 47.6% (10/21 were categorized as strong biofilm producers and 23.8% (5/21 as weak producers. Furthermore, 81% (17/21 of the isolates were methicillin resistant and mecA gene carriers. Resistance to ampicillin, erythromycin, and trimethoprim was observed in >70% of isolates screened. Each isolate showed a different PFGE macrorestriction pattern with similarity ranging between 0-95%. Among mecA-positive isolates, 14 (82% harbored a non-typeable SCCmec type: eight isolates were not positive for any ccr complex; four contained the mec complex A ccrAB1 and ccrC, one isolate contained mec complex A, ccrAB4 and ccrC, and one isolate contained the mec complex A, ccrAB1, ccrAB4, and ccrC. Two isolates harbored the association: mec complex A and ccrAB1. Only one strain was typeable as SCCmec III. CONCLUSIONS: The S. hominis isolates analyzed were variable biofilm producers had a high prevalence of methicillin resistance and resistance to other antibiotics, and high genetic diversity. The results of this study strongly suggested that S. hominis isolates harbor

Comparative Genotypes, Staphylococcal Cassette Chromosome mec (SCCmec) Genes and Antimicrobial Resistance amongst Staphylococcus epidermidis and Staphylococcus haemolyticus Isolates from Infections in Humans and Companion Animals

OpenAIRE

McManus, Brenda A.; Coleman, David C.; Deasy, Emily C.; Brennan, Gráinne I.; O’ Connell, Brian; Monecke, Stefan; Ehricht, Ralf; Leggett, Bernadette; Leonard, Nola; Shore, Anna C.

2015-01-01

This study compares the characteristics of Staphylococcus epidermidis (SE) and Staphylococcus haemolyticus (SH) isolates from epidemiologically unrelated infections in humans (Hu) (28 SE-Hu; 8 SH-Hu) and companion animals (CpA) (12 SE-CpA; 13 SH-CpA). All isolates underwent antimicrobial susceptibility testing, multilocus sequence typing and DNA microarray profiling to detect antimicrobial resistance and SCCmec-associated genes. All methicillin-resistant (MR) isolates (33/40 SE, 20/21 SH) und...

Thioridazine potentiates the effect of a beta-lactam antibiotic against Staphylococcus aureus independently of mecA expression

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Poulsen, Marianne Østergaard; Jacobsen, Kirstine; Bonde, Mette

2013-01-01

The neuroleptic antipsychotic derivate thioridazine has been shown to increase the susceptibility of a methicillin-resistant Staphylococcus aureus (MRSA) isolate towards dicloxacillin. The aim of this study was to investigate the combinatorial effect of the two drugs on a broad selection of staph......The neuroleptic antipsychotic derivate thioridazine has been shown to increase the susceptibility of a methicillin-resistant Staphylococcus aureus (MRSA) isolate towards dicloxacillin. The aim of this study was to investigate the combinatorial effect of the two drugs on a broad selection...... of staphylococcal strains by analyzing a large collection of MRSA strains carrying different types of SCCmec, as well as MSSA strains. Transcription and translation of the resistance marker PBP2a encoded by mecA within the SCCmec cassette were analyzed by primer extension and western blotting. We observed increased...... susceptibility to dicloxacillin in the presence of thioridazine in all tested MRSA isolates. In contrast to previously published results, the synergistic effect was also applicable to methicillin-susceptible S. aureus (MSSA). We conclude that the combination of dicloxacillin and thioridazine potentiates...

SCC mec typing and antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) from pigs of Northeast India.

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Rajkhowa, S; Sarma, D K; Pegu, S R

2016-12-01

Staphylococcus aureus is one of the most important pathogens of both humans and animal. Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen that causes serious infections both in hospitals and communities due to its multidrug resistance tendency. This study was undertaken to characterize the MRSA isolates from pigs and to determine the antimicrobial resistance of these isolates. Forty nine MRSA strains (one strain per positive pig) isolated from pigs of Northeast India were characterized by SCCmec typing and antimicrobial resistance. The overall prevalence of MRSA was 7.02 % with the highest prevalence recorded in pigs aged 1-3 months (P = 0.001) and in nasal samples (P = 0.005). Two SCC mec types (type III and V) were found in Indian pigs with predominance of type V. All isolates were resistant to penicillin. Seventeen resistance groups were observed where 87.75 % isolates showed multidrug resistance (showed resistance to three or more classes of antimicrobials). The most predominant resistance pattern observed was Oxytetracycline + Penicillin + Sulfadiazine + Tetracycline accounting 12.24 % of the isolates. The present study contributes to the understanding of characteristics and antimicrobial resistance of porcine MRSA isolates which in turn will help in devising strategy for the control of this pathogen. Findings of the study also throw light on multidrug resistance MRSA and emphasize the need for judicious use of antimicrobials in animal practice.

Meticillin-resistant Staphylococcus aureus with a novel mecA homologue in human and bovine populations in the UK and Denmark: a descriptive study.

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García-Álvarez, Laura; Holden, Matthew T G; Lindsay, Heather; Webb, Cerian R; Brown, Derek F J; Curran, Martin D; Walpole, Enid; Brooks, Karen; Pickard, Derek J; Teale, Christopher; Parkhill, Julian; Bentley, Stephen D; Edwards, Giles F; Girvan, E Kirsty; Kearns, Angela M; Pichon, Bruno; Hill, Robert L R; Larsen, Anders Rhod; Skov, Robert L; Peacock, Sharon J; Maskell, Duncan J; Holmes, Mark A

2011-08-01

Animals can act as a reservoir and source for the emergence of novel meticillin-resistant Staphylococcus aureus (MRSA) clones in human beings. Here, we report the discovery of a strain of S aureus (LGA251) isolated from bulk milk that was phenotypically resistant to meticillin but tested negative for the mecA gene and a preliminary investigation of the extent to which such strains are present in bovine and human populations. Isolates of bovine MRSA were obtained from the Veterinary Laboratories Agency in the UK, and isolates of human MRSA were obtained from diagnostic or reference laboratories (two in the UK and one in Denmark). From these collections, we searched for mecA PCR-negative bovine and human S aureus isolates showing phenotypic meticillin resistance. We used whole-genome sequencing to establish the genetic basis for the observed antibiotic resistance. A divergent mecA homologue (mecA(LGA251)) was discovered in the LGA251 genome located in a novel staphylococcal cassette chromosome mec element, designated type-XI SCCmec. The mecA(LGA251) was 70% identical to S aureus mecA homologues and was initially detected in 15 S aureus isolates from dairy cattle in England. These isolates were from three different multilocus sequence type lineages (CC130, CC705, and ST425); spa type t843 (associated with CC130) was identified in 60% of bovine isolates. When human mecA-negative MRSA isolates were tested, the mecA(LGA251) homologue was identified in 12 of 16 isolates from Scotland, 15 of 26 from England, and 24 of 32 from Denmark. As in cows, t843 was the most common spa type detected in human beings. Although routine culture and antimicrobial susceptibility testing will identify S aureus isolates with this novel mecA homologue as meticillin resistant, present confirmatory methods will not identify them as MRSA. New diagnostic guidelines for the detection of MRSA should consider the inclusion of tests for mecA(LGA251). Department for Environment, Food and Rural Affairs

Molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from patients with bacteremia based on MLST, SCCmec, spa, and agr locus types analysis.

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Goudarzi, Mehdi; Seyedjavadi, Sima Sadat; Nasiri, Mohammad Javad; Goudarzi, Hossein; Sajadi Nia, Raheleh; Dabiri, Hossein

2017-03-01

The widespread emergence of methicillin resistant Staphylococcus aureus, as a common cause of nosocomial infections, is becoming a serious concern in global public health. The objective of the present study was to investigate antimicrobial susceptibility pattern, frequency of virulence genes and molecular characteristics of methicillin-resistant Staphylococcus aureus strains isolated from patients with bacteremia. A total of 128 methicillin-resistant Staphylococcus aureus isolates were collected during February 2015 to January 2016. In vitro antimicrobial susceptibility of the isolates was assessed using the disk diffusion method. Conventional PCR was performed for the detection of adhesion (can, bbp, ebp, fnbB, fnbA, clfB, clfA) and toxin (etb, eta, pvl, tst) encoding genes, determining the agr type, SCCmec, MLST and spa typing of the isolates. All the methicillin-resistant Staphylococcus aureus isolates were found to be sensitive to linezolid, teicoplanin, and vancomycin. Resistance to the tested antibiotics varied from 97.7% for penicillin to 24.2% for mupirocin. The rate of multi drug resistance (MDR) in the present study was 97.7%. The most commonly detected toxin and adhesion genes were tst (58.6%), and clfB (100%), respectively. The majority of SCCmec III isolates were found in agr group I while SCCmec IV and II isolates were distributed among agr group III. Multilocus Sequence Typing (MLST) of the MRSA isolates showed five different sequence types: ST239 (43%), ST22 (39.8%), ST585 (10.9%), ST45 (3.9%) and ST240 (2.3%). All of the pvl positive strains belonged to ST22-SCCmec IV/t790 clone and were MDR. Among different 7 spa types, the most common were t790 (27.3%), t037 (21.9%), and t030 (14.1%). spa types t016, t924 and spa type t383 were reported for the first time from Asia and Iran, respectively. It was shown that spa types circulating in the studied hospitals varied which support the need to perform future surveillance studies in order to understand

Isolation of coagulase-positive staphylococci from bitches' colostrum and milk and genetic typing of methicillin-resistant Staphylococcus pseudintermedius strains.

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Rota, Ada; Corrò, Michela; Drigo, Ilenia; Bortolami, Alessio; Börjesson, Stefan

2015-07-23

Among the coagulase-positive, potentially pathogenic staphylococci, Staphylococcus pseudintermedius has been frequently isolated from bitches' milk. This organism colonizes the mammary gland or causes infection, while S. aureus has been only occasionally reported. The objective of this study was to investigate the occurrence and persistence of coagulase-positive staphylococci in the colostrum and milk of postpartum bitches, either treated or untreated with antimicrobials, and to assess the incidence, antibiotic resistance profile and genetic type of the methicillin-resistant strains. On postpartum D1, D7 and D15, drops of secretion were collected from the mammary glands of 27 postpartum bitches, nine of which were treated with antimicrobials. Coagulase-positive staphylococci were identified, antimicrobial susceptibility and the presence of mecA were tested and the genetic profile of methicillin-resistant strains was assessed. Staphylococcus pseudintermedius was the only coagulase-positive staphylococcus isolated, and its presence was detected in 21 out of 27 bitches and in 66 out of 145 swabs. In a single bitch, it caused puerperal mastitis. In untreated bitches, the frequency of isolation was lower in colostrum than in milk. All of the isolates except one were resistant to at least three antimicrobial classes, while 14 out of 66 S. pseudintermedius strains were methicillin-resistant mecA positive (MRSP) and were isolated from eight bitches housed in the same breeding kennel. A significant association was found between antimicrobial treatment and the presence of MRSP. Six of the 12 typed isolates belonged to spa-type t02 carrying SCCmec II/III, and another six were non-typeable with spa carrying SCCmec IV. The t02-SCCmec II/III isolates were sequence type (ST) 71; four NT-SCCmec IV isolates were ST258 and two were ST369. PFGE showed that isolates from the same dog had identical band patterns, while isolates from different dogs had unique band patterns. MRSP strains

Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India.

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Hiral Mistry

Full Text Available Bovine mastitis caused by multidrug resistant Staphylococcus aureus is a huge problem reported worldwide, resulting in prolonged antibiotic treatment and death of livestock. The current study is focused on surveillance of antibiotic susceptibility along with genotypic and phenotypic characterization of the pathogenic S. aureus strains causing mastitis in India. One hundred and sixty seven milk samples were collected from mastitis-affected cows from different farms in India resulting in thirty nine isolated S. aureus strains. Antibiotic sensitivity profiling revealed the majority of the strains (n = 24 to be multidrug resistant and eleven strains showed reduced susceptibility to vancomycin (MICs = 2μg/ml. All strains were oxacillin sensitive, but 19 strains were positive for the mecA gene, which revealed the occurrence of oxacillin susceptible mecA positive strains (OS-MRSA for the first time from India. Additionally, 32 strains were positive for the pvl gene, a virulence determinant; of these 17 were also OS-MRSA strains. Molecular characterization based on multilocus sequence typing (MLST, spa typing, agr typing and SCCmec classification revealed strains belonging to different groups. Moreover, strains showed spa types (t2526, t9602 and MLST sequence types, ST-72, ST-88 and ST-239 which have been earlier reported in human infections. The prevalence of OS-MRSA strains indicates the importance of including both the genetic and phenotypic tests in characterizing S. aureus strains. Increased genotypic variability with strain related to human infections and pvl positive isolates indicates a worrisome situation with the possibility of bilateral transfer.

Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India.

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Mistry, Hiral; Sharma, Paresh; Mahato, Sudipta; Saravanan, R; Kumar, P Anand; Bhandari, Vasundhra

2016-01-01

Bovine mastitis caused by multidrug resistant Staphylococcus aureus is a huge problem reported worldwide, resulting in prolonged antibiotic treatment and death of livestock. The current study is focused on surveillance of antibiotic susceptibility along with genotypic and phenotypic characterization of the pathogenic S. aureus strains causing mastitis in India. One hundred and sixty seven milk samples were collected from mastitis-affected cows from different farms in India resulting in thirty nine isolated S. aureus strains. Antibiotic sensitivity profiling revealed the majority of the strains (n = 24) to be multidrug resistant and eleven strains showed reduced susceptibility to vancomycin (MICs = 2μg/ml). All strains were oxacillin sensitive, but 19 strains were positive for the mecA gene, which revealed the occurrence of oxacillin susceptible mecA positive strains (OS-MRSA) for the first time from India. Additionally, 32 strains were positive for the pvl gene, a virulence determinant; of these 17 were also OS-MRSA strains. Molecular characterization based on multilocus sequence typing (MLST), spa typing, agr typing and SCCmec classification revealed strains belonging to different groups. Moreover, strains showed spa types (t2526, t9602) and MLST sequence types, ST-72, ST-88 and ST-239 which have been earlier reported in human infections. The prevalence of OS-MRSA strains indicates the importance of including both the genetic and phenotypic tests in characterizing S. aureus strains. Increased genotypic variability with strain related to human infections and pvl positive isolates indicates a worrisome situation with the possibility of bilateral transfer.

Methicillin-resistant Staphylococcus aureus nasal carriage between healthy students of medical and nonmedical universities.

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Abroo, Soleiman; Hosseini Jazani, Nima; Sharifi, Yaeghob

2017-07-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a challenge for public health, and community-acquired (CA) infections seem to be increasing among people in different areas. A total of 700 healthy student volunteers residing in dormitories of universities in Urmia, Iran, were enrolled in this study. After identification of the isolates, antibiotic susceptibility, presence of mecA and pvl genes, and staphylococcal cassette chromosome mec (SCCmec) typing were evaluated. Nasal screening identified 137 (19.6%) carriers of S aureus, and 18 (13.14%) were MRSA isolates. The antimicrobial susceptibility patterns of isolates revealed high resistance to penicillin (93.4%). All isolates were sensitive to vancomycin. The SCCmec typing showed that most MRSA strains belonged to SCCmec type IV (n = 14; 77.8%). Only 1 (5.56%) MRSA isolates carried the pvl gene. Our findings revealed the relatively high frequency of S aureus nasal carriers and the advent of multidrug resistance among these isolates. Most MRSA isolates were SCCmec type IV; the transfer of such MRSA strains from carriers to other individuals in crowded living conditions such as dormitories can act as a risk factor for outbreak of CA MRSA and is a serious threat for the study groups. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Molecular Characterization of Methicillin Resistant Staphylococcus aureus Strains Isolated from Intensive Care Units in Iran: ST22-SCCmec IV/t790 Emerges as the Major Clone.

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Goudarzi, Mehdi; Goudarzi, Hossein; Sá Figueiredo, Agnes Marie; Udo, Edet E; Fazeli, Maryam; Asadzadeh, Mohammad; Seyedjavadi, Sima Sadat

2016-01-01

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) in different patient populations is a major public health concern. This study determined the prevalence and distribution of circulating molecular types of MRSA in hospitalized patients in ICU of hospitals in Tehran. A total of 70 MRSA isolates were collected from patients in eight hospitals. Antimicrobial resistance patterns were determined using the disk diffusion method. The presence of toxin encoding genes and the vancomycin resistance gene were determined by PCR. The MRSA isolates were further analyzed using multi-locus sequence, spa, SCCmec, and agr typing. The MRSA prevalence was 93.3%. Antimicrobial susceptibility testing revealed a high resistance rate (97.1%) to ampicillin and penicillin. The rate of resistance to the majority of antibiotics tested was 30% to 71.4%. Two isolates belonging to the ST22-SCCmec IV/t790 clone (MIC ≥ 8 μg/ml) had intermediate resistance to vancomycin. The majority of MRSA isolates (24.3%) were associated with the ST22-SCCmec IV/t790 clone; the other MRSA clones were ST859-SCCmec IV/t969 (18.6%), ST239-SCCmec III/t037 (17.1%), and ST291-SCCmec IV/t030 (8.6%). The circulating MRSA strains in Iranian hospitals were genetically diverse with a relatively high prevalence of the ST22-SCCmec IV/t790 clone. These findings support the need for future surveillance studies on MRSA to better elucidate the distribution of existing MRSA clones and detect emergence of new MRSA clones.

Emergence of community-acquired methicillin-resistant Staphylococcus aureus in an Iranian referral paediatric hospital.

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Mamishi, S; Mahmoudi, S; Bahador, A; Matini, H; Movahedi, Z; Sadeghi, R H; Pourakbari, B

2015-01-01

The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals has been changed in recent years due to the arrival of community-associated MRSA (CA-MRSA) strains into healthcare settings. The aim of this study is to investigate the distribution of staphylococcal cassette chromosome mec (SCCmec) type V as well as SCCmec IV subtypes, which have been associated with community-acquired infection among healthcare-associated MRSA (HA-MRSA) isolates. Antimicrobial susceptibility, SCCmec type, spa type and the presence of Panton-Valentine leukocidin (PVL) genes were determined for all HA-MRSA isolates in an Iranian referral hospital. In this study of 48 HA-MRSA isolates, 13 (27%), three (6.2%), five (10.4%) and one (2%) belonged to SCCmec subtypes IVa, IVb, IVc and IVd, respectively. Only two isolates (4.2%) belonged to SCCmec types V Notably, one isolate was found to harbour concurrent SCCmec subtypes IVb and IVd. MRSA containing SCCmec subtype IVb, IVc and IVd as well as type V isolates were all susceptible to chloramphenicol, clindamycin and rifampicin, while the sensitivity to these antibiotics was lower among MRSA containing SCCmec subtype IVa. The most frequently observed spa ttype was t037, accounting for 88% (22/25). Three other spa type was t002, t1816 and t4478. Large reservoirs of MRSA containing type IV subtypes and type V now exist in patients in this Iranian hospital. Therefore, effective infection control management in order to control the spread of CA-MRSA is highly recommended.

Cost-effectiveness and efficacy of spa, SCCmec, and PVL genotyping of methicillin-resistant Staphylococcus aureus as compared to pulsed-field gel Electrophoresis.

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Vincent Li

Full Text Available Pulsed-field gel electrophoresis (PFGE is a valuable molecular typing assay used for methicillin-resistant Staphylococcus aureus (MRSA surveillance and genotyping. However, there are several limitations associated with PFGE. In Alberta, Canada, the significant increase in the number of MRSA isolates submitted to the Provincial Laboratory for Public Health (ProvLab for PFGE typing led to the need for an alternative genotyping method. In this study, we describe the transition from PFGE to Staphylococcus protein A (spa, Staphylococcal cassette chromosome (SCCmec, and Panton-Valentine leukocidin (PVL typing. A total of 1915 clinical MRSA isolates collected from 2005 to 2009 were used to develop and validate an algorithm for assigning PFGE epidemic types using spa, SCCmec, and PVL typing and the resulting data was used to populate a new Alberta MRSA typing database. An additional 12620 clinical MRSA isolates collected from 2010 to 2012 as part of ongoing routine molecular testing at ProvLab were characterized using the new typing algorithm and the Alberta MRSA typing database. Switching to spa, SCCmec, and PVL from PFGE typing substantially reduced hands-on and turn-around times while maintaining historical PFGE epidemic type designations. This led to an approximate $77,000 reduction in costs from 2010 to 2012. PFGE typing is still required for a small subset of MRSA isolates that have spa types that are rare, novel, or associated with more than one PFGE epidemic type.

New multilocus sequence typing of MRSA in São Paulo, Brazil

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M.S. Carmo

2011-10-01

Full Text Available An increased incidence of nosocomial and community-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA has been observed worldwide. The molecular characterization of MRSA has played an important role in demonstrating the existence of internationally disseminated clones. The use of molecular biology methods in the surveillance programs has enabled the tracking of MRSA spread within and among hospitals. These data are useful to alert nosocomial infection control programs about the potential introduction of these epidemic clones in their areas. Four MRSA blood culture isolates from patients hospitalized at two hospitals in the city of São Paulo, Brazil, were analyzed; one of them was community acquired. The isolates were characterized as SCCmec, mecA and PVL by PCR, pulsed-field gel electrophoresis (PFGE profile and molecular sequence typing (MLST genotyping. The isolates presented type IV SCCmec, and none proved to be positive for PVL. The isolates showed a PFGE profile similar to the pediatric clone. MLST genotyping demonstrated that the isolates belonged to clonal complex 5 (CC5, showing a new yqiL allele gene, resulting in a new sequence typing (ST (1176. Our results showed that strains of MRSA carrying a new ST are emerging in community and nosocomial infections, including bacteremia, in São Paulo, Brazil.

Molecular epidemiology of nasal isolates of methicillin-resistant Staphylococcus aureus from Jordan

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Amin A. Aqel

2015-01-01

Full Text Available Summary: Asymptomatic carriage of methicillin-resistant Staphylococcus aureus (MRSA can predispose the host to a wide range of infections. To inform public health strategies, this study sought to determine the prevalence and the phenotypic and genotypic characteristics of MRSA from nasal swabs of health care workers (HCWs and other healthy individuals in Jordan. Overall, 716 nasal swabs were collected from 297 HCWs, 141 adults and 278 children in the community. MRSA was recovered from 56 (7.8% nasal swabs, which represented carriage rates of 10.1%, 4.3% and 7.2% among HCWs, adults and children, respectively. The MRSA isolates were resistant to oxacillin (100%, erythromycin (42.8%, tetracycline (37.5%, clindamycin (5.3%, fucidin (5.3%, and ciprofloxacin (3.5%. A total of 17 different spa types belonging to eight different clonal complexes (CCs were identified. All isolates were mecA positive, and mecC-MRSA was not detected. Analysis of the staphylococcal cassette chromosome mec (SCCmec elements revealed that the majority (54; 96.4% of the samples harbored the smaller type IV and V elements (the most common were SCCmec IVa or IVc, and there were two each of the IVg and V elements, and two were nontypable. The genes for Panton-Valentine leukocidin (luk-PV were detected in 5.4% of the study isolates. A tst-positive, CC22-MRSA-SCCmecIVa clone (spa type t223 was identified as the dominant MRSA lineage among the nasal carriage isolates from both HCWs and other individuals (adults and children in the community. These findings provide important information for public health personnel for the formulation of effective infection prevention and control strategies. Studies to further our understanding of the distribution, pathogenicity, transmissibility and fitness of this lineage would be prudent. Keywords: MRSA, Healthcare workers, Healthy individuals, SCCmecIVa

Evaluation of antimicrobial susceptibilities and virulence factors of Staphylococcus aureus strains isolated from community-acquired and health-care associated pediatric infections.

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Karbuz, Adem; Karahan, Zeynep Ceren; Aldemir-Kocabaş, Bilge; Tekeli, Alper; Özdemir, Halil; Güriz, Haluk; Gökdemir, Refik; İnce, Erdal; Çiftçi, Ergin

2017-01-01

Karbuz A, Karahan ZC, Aldemir-Kocabaş B, Tekeli A, Özdemir H, Güriz H, Gökdemir R, İnce E, Çiftçi E. Evaluation of antimicrobial susceptibilities and virulence factors of Staphylococcus aureus strains isolated from community-acquired and health-care associated pediatric infections. Turk J Pediatr 2017; 59: 395-403. The aim of this study was to investigate the enterotoxins and Panton-Valentine leukocidin (PVL) gene as virulence factor, identification if antimicrobial sensitivity patterns, agr (accessory gene regulator) types and sequence types and in resistant cases to obtain SCCmec (staphylococcal cassette chromosome mec) gene types which will be helpful to decide empirical therapy and future health politics for S. aureus species. Total of 150 isolates of S. aureus were isolated from the cultures of the child patients in January 2011 and December 2012. In this study, the penicillin resistance was observed as 93.8%. PVL and mecA was detected positive in 8.7% and in 6% of all S. aureus strains, respectively. Two MRSA (methicillin resistant S.aureus) strains were detected as SCCmec type III and SCCmec type V and five MRSA strains were detected as SCCmec type IV. SET-I and SET-G were the most common detected enterotoxins. In both community-associated and healthcare-associated MRSA strains, agr type 1 was detected most commonly. The most common sequence types were ST737 in 13 patients than ST22 in eight patients and ST121 in six patients. This study highlights a necessity to review the cause of small changes in the structural genes in order to determine whether it is a cause or outcome; community-acquired and healthcare associated strains overlap.

Discriminatory Indices of Typing Methods for Epidemiologic Analysis of Contemporary Staphylococcus aureus Strains.

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Rodriguez, Marcela; Hogan, Patrick G; Satola, Sarah W; Crispell, Emily; Wylie, Todd; Gao, Hongyu; Sodergren, Erica; Weinstock, George M; Burnham, Carey-Ann D; Fritz, Stephanie A

2015-09-01

Historically, a number of typing methods have been evaluated for Staphylococcus aureus strain characterization. The emergence of contemporary strains of community-associated S. aureus, and the ensuing epidemic with a predominant strain type (USA300), necessitates re-evaluation of the discriminatory power of these typing methods for discerning molecular epidemiology and transmission dynamics, essential to investigations of hospital and community outbreaks. We compared the discriminatory index of 5 typing methods for contemporary S. aureus strain characterization. Children presenting to St. Louis Children's Hospital and community pediatric practices in St. Louis, Missouri (MO), with community-associated S. aureus infections were enrolled. Repetitive sequence-based PCR (repPCR), pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), staphylococcal protein A (spa), and staphylococcal cassette chromosome (SCC) mec typing were performed on 200 S. aureus isolates. The discriminatory index of each method was calculated using the standard formula for this metric, where a value of 1 is highly discriminatory and a value of 0 is not discriminatory. Overall, we identified 26 distinct strain types by repPCR, 17 strain types by PFGE, 30 strain types by MLST, 68 strain types by spa typing, and 5 strain types by SCCmec typing. RepPCR had the highest discriminatory index (D) of all methods (D = 0.88), followed by spa typing (D = 0.87), MLST (D = 0.84), PFGE (D = 0.76), and SCCmec typing (D = 0.60). The method with the highest D among MRSA isolates was repPCR (D = 0.64) followed by spa typing (D = 0.45) and MLST (D = 0.44). The method with the highest D among MSSA isolates was spa typing (D = 0.98), followed by MLST (D = 0.93), repPCR (D = 0.92), and PFGE (D = 0.89). Among isolates designated USA300 by PFGE, repPCR was most discriminatory, with 10 distinct strain types identified (D = 0.63). We identified 45

An Unexpected Location of the Arginine Catabolic Mobile Element (ACME) in a USA300-Related MRSA Strain

DEFF Research Database (Denmark)

Damkjær Bartels, Mette; Hansen, Lars H.; Boye, Kit

2011-01-01

In methicillin resistant Staphylococcus aureus (MRSA), the arginine catabolic mobile element (ACME) was initially described in USA300 (t008-ST8) where it is located downstream of the staphylococcal cassette chromosome mec (SCCmec). A common health-care associated MRSA in Copenhagen, Denmark (t024......-ST8) is clonally related to USA300 and is frequently PCR positive for the ACME specific arcA-gene. This study is the first to describe an ACME element upstream of the SCCmec in MRSA. By traditional SCCmec typing schemes, the SCCmec of t024-ST8 strain M1 carries SCCmec IVa, but full sequencing...... of SCCmec, M1 had two new DR between the orfX gene and the J3 region of the SCCmec. The region between the orfX DR (DR1) and DR2 contained the ccrAB4 genes. An ACME II-like element was located between DR2 and DR3. The entire 26,468 bp sequence between DR1 and DR3 was highly similar to parts of the ACME...

Molecular characterisation of methicillin-resistant Staphylococcus aureus (MRSA) isolated at a large referral hospital in Zambia.

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Samutela, Mulemba Tillika; Kalonda, Annie; Mwansa, James; Lukwesa-Musyani, Chileshe; Mwaba, John; Mumbula, Enoch Mulowa; Mwenya, Darlington; Simulundu, Edgar; Kwenda, Geoffrey

2017-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) is globally recognized as an important public health problem. Whereas comprehensive molecular typing data of MRSA strains is available, particularly in Europe, North America and Australia, similar information is very limited in sub-Saharan Africa including Zambia. In this study, thirty two clinical isolates of Staphylococcus aureus , collected at a large referral hospital in Lusaka, Zambia between June 2009 and December 2012 were analysed by Staphylococcal cassette chromosome mec (SCCmec), Staphylococcus protein A gene typing (spa) and detection of the Panton-Valentine Leukocidin genes (pvl) . Three SCC mec types were identified namely SCC mec type IV (65.6%), SCCmec type III (21.9%), SCC mec type I (3.1%). Nine point four percent (9.4%) of the isolates were untypable. Five spa types, which included a novel type, were detected and the most prevalent spa type was t064 (40.6%). Other spa types included spa types t2104 (31.3%), t355 (3.1%) and t1257 (21.9%). The pvl genes were detected in 3 out of 32 isolates. These molecular typing data indicated that the MRSA strains collected in Lusaka were diverse. Although the source of these MRSA was not established, these results stress the need for assessing infection prevention and control procedures at this health-care facility in order to curtail possible nosocomial infections. Furthermore, country-wide surveillance of MRSA in both the community and health-care facilities is recommended for infection prevention and control. To our knowledge, this represents the first study to characterise MRSA using molecular tools in Zambia.

Methicillin resistance gene diversity in staphylococci isolated from captive and free-ranging wallabies

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Michelle M. S. Chen

2016-05-01

Full Text Available Background: Infection with methicillin-resistant staphylococci (MRS can be life-threatening in humans and its presence in animals is a cause for public health concern. The aim of this study was to measure the prevalence of MRS in captive and free-ranging wallabies over a 16-month period in South Australia, Australia. Materials and methods: Eighty-nine purified staphylococcal isolates recovered from 98 captive and free-ranging wallabies' anterior nasal swabs were used in this study. All isolates were tested for the presence of the mecA, mecA1, and mecC genes. Multiplex PCR-directed SCCmec-typing, ccrB-typing, and determination of the minimal inhibitory concentration of oxacillin were performed on mec-positive isolates. Results and discussion: In total, 11 non-Staphylococcus aureus MRS were isolated from 7 out of 98 animals, corresponding to a 7.1% carriage rate. The SCCmec types I, III, and V were identified by multiplex PCR and sequencing of the ccrB gene. This is the first report of MRS carriage in both captive and free-ranging wallabies in Australia. These data demonstrate a low prevalence of MRS and no association between wallaby captivity status and MRS carriage could be assigned. These animals may act as a reservoir for the exchange of genetic elements between staphylococci. Furthermore, the mecA genes of animal isolates were identical to that found in human MRS strains and thus the possibility of zoonotic transfer must be considered.

Molecular epidemiology of community-onset methicillin-resistant Staphylococcus aureus infections in Israel.

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Biber, A; Parizade, M; Taran, D; Jaber, H; Berla, E; Rubin, C; Rahav, G; Glikman, D; Regev-Yochay, G

2015-08-01

Data on community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) in Israel are scarce. The objective of this study was to characterize the major CA-MRSA clones in Israel. All clinical MRSA isolates detected in the community during a period of 2.5 years (2011-2013) from individuals insured by a major health maintenance organization in Israel were collected, with additional data from medical records. Antibiotic susceptibility patterns and staphylococcal chromosomal cassette mec (SCCmec) typing were determined. SCCmec IV and V isolates were further typed by pulsed-field gel electrophoresis (PFGE), spa typing, and detection of a panel of toxin genes. MRSA were detected in 280 patients, mostly from skin infections. Patients with SCCmec IV (n = 120, 43 %) were younger (p Israel, approximately 20 % are typical CA-MRSA clones, mainly USA300 and a local clone, t991.

Enhanced discrimination of highly clonal ST22-methicillin-resistant Staphylococcus aureus IV isolates achieved by combining spa, dru, and pulsed-field gel electrophoresis typing data.

LENUS (Irish Health Repository)

Shore, Anna C

2010-05-01

ST22-methicillin-resistant Staphylococcus aureus type IV (ST22-MRSA-IV) is endemic in Irish hospitals and is designated antibiogram-resistogram type-pulsed-field group (AR-PFG) 06-01. Isolates of this highly clonal strain exhibit limited numbers of pulsed-field gel electrophoresis (PFGE) patterns and spa types. This study investigated whether combining PFGE and spa typing with DNA sequencing of the staphylococcal cassette chromosome mec element (SCCmec)-associated direct repeat unit (dru typing) would improve isolate discrimination. A total of 173 MRSA isolates recovered in one Irish hospital during periods in 2007 and 2008 were investigated using antibiogram-resistogram (AR), PFGE, spa, dru, and SCCmec typing. Isolates representative of each of the 17 pulsed-field group 01 (PFG-01) spa types identified underwent multilocus sequence typing, and all isolates were ST22. Ninety-seven percent of isolates (168 of 173) exhibited AR-PFG 06-01 or closely related AR patterns, and 163 of these isolates harbored SCCmec type IVh. The combination of PFGE, spa, and dru typing methods significantly improved discrimination of the 168 PFG-01 isolates, yielding 65 type combinations with a Simpson\\'s index of diversity (SID) of 96.53, compared to (i) pairwise combinations of spa and dru typing, spa and PFGE typing, and dru and PFGE typing, which yielded 37, 44, and 43 type combinations with SIDs of 90.84, 91.00, and 93.57, respectively, or (ii) individual spa, dru, and PFGE typing methods, which yielded 17, 17, and 21 types with SIDs of 66.9, 77.83, and 81.34, respectively. Analysis of epidemiological information for a subset of PFG-01 isolates validated the relationships inferred using combined PFGE, spa, and dru typing data. This approach significantly enhances discrimination of ST22-MRSA-IV isolates and could be applied to epidemiological investigations of other highly clonal MRSA strains.

Nasal carriage of methicillin resistant staphylococci

DEFF Research Database (Denmark)

Faria, Nuno A; Conceição, Teresa; Miragaia, Maria

2014-01-01

Coagulase-negative staphylococci (CoNS) are believed to function as reservoirs, as well as possible sources of staphylococcal chromosome cassette mec (SCCmec) to Staphylococcus aureus, but the frequency, preferred partners, and factors promoting SCCmec transfer are not known. Such postulated...

The human clone ST22 SCCmec IV methicillin-resistant Staphylococcus aureus isolated from swine herds and wild primates in Nepal: is man the common source?

Science.gov (United States)

Roberts, Marilyn C; Joshi, Prabhu Raj; Greninger, Alexander L; Melendez, Daira; Paudel, Saroj; Acharya, Mahesh; Bimali, Nabin Kishor; Koju, Narayan P; No, David; Chalise, Mukesh; Kyes, Randall C

2018-05-01

Swine nasal samples [n = 282] were collected from 12 randomly selected farms around Kathmandu, Nepal, from healthy animals. In addition, wild monkey (Macaca mulatta) saliva samples [n = 59] were collected near temples areas in Kathmandu using a non-invasive sampling technique. All samples were processed for MRSA using standardized selective media and conventional biochemical tests. MRSA verification was done and isolates characterized by SCCmec, multilocus sequence typing, whole genome sequencing [WGS] and antibiotic susceptibilities. Six (2.1%) swine MRSA were isolated from five of the different swine herds tested, five were ST22 type IV and one ST88 type V. Four (6.8%) macaques MRSA were isolated, with three ST22 SCCmec type IV and one ST239 type III. WGS sequencing showed that the eight ciprofloxacin resistant ST22 isolates carried gyrA mutation [S84L]. Six isolates carried the erm(C) genes, five isolates carried aacC-aphD genes and four isolates carried blaZ genes. The swine linezolid resistant ST22 did not carry any known acquired linezolid resistance genes but had a mutation in ribosomal protein L22 [A29V] and an insertion in L4 [68KG69], both previously associated with linezolid resistance. Multiple virulence factors were also identified. This is the first time MRSA ST22 SCCmec IV has been isolated from livestock or primates.

Characterization of a Novel Arginine Catabolic Mobile Element (ACME) and Staphylococcal Chromosomal Cassette mec Composite Island with Significant Homology to Staphylococcus epidermidis ACME type II in Methicillin-Resistant Staphylococcus aureus Genotype ST22-MRSA-IV.

LENUS (Irish Health Repository)

Shore, Anna C

2011-02-22

The arginine catabolic mobile element (ACME) is prevalent among ST8-MRSA-IVa (USA300) isolates and evidence suggests that ACME enhances the ability of ST8-MRSA-IVa to grow and survive on its host. ACME has been identified in a small number of isolates belonging to other MRSA clones but is widespread among coagulase-negative staphylococci (CoNS). This study reports the first description of ACME in two distinct strains of the pandemic ST22-MRSA-IV clone. A total of 238 MRSA isolates recovered in Ireland between 1971 and 2008 were investigated for ACME using a DNA microarray. Twenty-three isolates (9.7%) were ACME-positive, all were either MRSA genotype ST8-MRSA-IVa (7\\/23, 30%) or ST22-MRSA-IV (16\\/23, 70%). Whole-genome sequencing and comprehensive molecular characterization revealed the presence of a novel 46-kb ACME and SCCmec composite island (ACME\\/SCCmec-CI) in ST22-MRSA-IVh isolates (n = 15). This ACME\\/SCCmec-CI consists of a 12-kb DNA region previously identified in ACME type II in S. epidermidis ATCC 12228, a truncated copy of the J1 region of SCCmec I and a complete SCCmec IVh element. The composite island has a novel genetic organization with ACME located within orfX and SCCmec located downstream of ACME. One pvl-positive ST22-MRSA-IVa isolate carried ACME located downstream of SCCmec IVa as previously described in ST8-MRSA-IVa. These results suggest that ACME has been acquired by ST22-MRSA-IV on two independent occasions. At least one of these instances may have involved horizontal transfer and recombination events between MRSA and CoNS. The presence of ACME may enhance dissemination of ST22-MRSA-IV, an already successful MRSA clone.

Characteristics related to antimicrobial resistance and biofilm formation of widespread methicillin-resistant Staphylococcus epidermidis ST2 and ST23 lineages in Rio de Janeiro hospitals, Brazil.

Science.gov (United States)

Iorio, Natalia Lopes Pontes; Caboclo, Roberta Ferreira; Azevedo, Milena Borgo; Barcellos, Ariane Guimarães; Neves, Felipe Piedade Gonçalves; Domingues, Regina Maria Cavalcanti Pilotto; dos Santos, Kátia Regina Netto

2012-01-01

Staphylococcus epidermidis is a leading cause of hospital-acquired infections, mostly associated with the use of medical devices in seriously ill or immunocompromised patients. Currently, the characteristics of methicillin-resistant S. epidermidis (MRSE) isolates from Rio de Janeiro hospitals are unknown. In this study, staphylococcal chromosomal cassette mec (SCCmec) types, antimicrobial susceptibility profiles, biofilm formation genes, and multilocus sequence types (MLST) were investigated in 35 MRSE clinical isolates. The collection of isolates was previously well characterized by pulsed-field gel electrophoresis (PFGE) into 2 main genotypes (A and B, 22 isolates) and 10 sporadic genotypes (13 isolates). MLST revealed a total of 8 different sequence types (STs), but ST2 and ST23, which were icaAB-positive, represented the majority (71.4%) of MRSE isolates tested. Almost all isolates (91.4%) belonged to clonal complex 2. SCCmec types III and IV were identified among 71.4% of the isolates, while the remaining was nontypeable. The predominant MRSE genotypes were defined as SCCmec type III/ST2 (PFGE type A) and SCCmec type IV/ST23 (PFGE type B) isolates, which were both associated with high antimicrobial resistance and presence of biofilm-related genes. Copyright © 2012 Elsevier Inc. All rights reserved.

SCCmec Type IX Element in Methicillin Resistant Staphylococcusaureusspa Type t337 (CC9) Isolated from Pigs and Pork in Thailand

DEFF Research Database (Denmark)

Vestergaard, Martin; Cavaco, Lina M; Sirichote, Pantip

2012-01-01

blaZ, aac-aphD, vga(A), tetM, and a tet efflux marker, in all strains and additionally ermB and aadD, cat and fex(A) in the pork isolates. None of the isolates were found PVL-positive, but enterotoxins were identified in all isolates. To our knowledge, only a few descriptions of MRSA in livestock...... and food products in Thailand have been observed but this is the first observation of MRSA CC9 associated with SCCmec IX in pork. This study indicates a likely widespread distribution of MRSA in pig and pork in Thailand and further investigation on the prevalence and importance of livestock associated MRSA...

Colonization of butchers with livestock-associated methicillin-resistant Staphylococcus aureus

DEFF Research Database (Denmark)

Boost, Maureen; Ho, J.; Guardabassi, Luca

2013-01-01

contamination levels of 10% of retail pork were reported from the Netherlands and Canada, there are limited data of contamination rates of workers handling raw meat. We investigated the rates of MRSA contamination of local butchers working in wet markets, where recently slaughtered pigs are cut up. Nasal swabs...... collected from 300 pork butchers at markets throughout Hong Kong were enriched in brain heart infusion broth with 5% salt and cultured on MRSASelect(®) . Isolates were confirmed as Staphylococcus aureus and susceptibility testing performed. The presence of mecA was confirmed, SCCmec and spa type determined...... and relatedness investigated by PFGE. Subjects completed a questionnaire on MRSA carriage risk factors. Seventeen samples (5.6%) yielded MRSA, 15 harbouring SCCmec IVb. Ten strains were t899 (CC9), previously reported from local pig carcasses. Five strains were healthcare associated: SCCmec type II, t701(CC6...

Characterisation of virulence genes in methicillin susceptible and resistant Staphylococcus aureus isolates from a paediatric population in a university hospital of Medellín, Colombia

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Judy Natalia Jiménez

2011-12-01

Full Text Available Virulence and antibiotic resistance are significant determinants of the types of infections caused by Staphylococcus aureus and paediatric groups remain among the most commonly affected populations. The goal of this study was to characterise virulence genes of methicillin-susceptible S. aureus (MSSA and methicillin-resistant S. aureus (MRSA strains isolated from a paediatric population of a Colombian University Hospital during 2009. Sixty MSSA and MRSA isolates were obtained from paediatric patients between zero-14 years. We identified the genes encoding virulence factors, which included Panton-Valentine leucocidine (PVL, staphylococcal enterotoxins A-E, exfoliative toxins A and B and toxic shock syndrome toxin 1. Typing of the staphylococcal chromosome cassette mec (SCCmec was performed in MRSA strains. The virulence genes were more diverse and frequent in MSSA than in MRSA isolates (83% vs. 73%. MRSA strains harboured SCCmec types IVc (60%, I (30%, IVa (7% and V (3%. SCCmec type IVc isolates frequently carried the PVL encoding genes and harboured virulence determinants resembling susceptible strains while SCCmec type I isolates were often negative. PVL was not exclusive to skin and soft tissue infections. As previously suggested, these differences in the distribution of virulence factor genes may be due to the fitness cost associated with methicillin resistance.

Characterisation of virulence genes in methicillin susceptible and resistant Staphylococcus aureus isolates from a paediatric population in a university hospital of Medellín, Colombia.

Science.gov (United States)

Jiménez, Judy Natalia; Ocampo, Ana María; Vanegas, Johanna Marcela; Rodríguez, Erika Andrea; Garcés, Carlos Guillermo; Patiño, Luz Adriana; Ospina, Sigifredo; Correa, Margarita María

2011-12-01

Virulence and antibiotic resistance are significant determinants of the types of infections caused by Staphylococcus aureus and paediatric groups remain among the most commonly affected populations. The goal of this study was to characterise virulence genes of methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains isolated from a paediatric population of a Colombian University Hospital during 2009. Sixty MSSA and MRSA isolates were obtained from paediatric patients between zero-14 years. We identified the genes encoding virulence factors, which included Panton-Valentine leucocidine (PVL), staphylococcal enterotoxins A-E, exfoliative toxins A and B and toxic shock syndrome toxin 1. Typing of the staphylococcal chromosome cassette mec (SCCmec) was performed in MRSA strains. The virulence genes were more diverse and frequent in MSSA than in MRSA isolates (83% vs. 73%). MRSA strains harboured SCCmec types IVc (60%), I (30%), IVa (7%) and V (3%). SCCmec type IVc isolates frequently carried the PVL encoding genes and harboured virulence determinants resembling susceptible strains while SCCmec type I isolates were often negative. PVL was not exclusive to skin and soft tissue infections. As previously suggested, these differences in the distribution of virulence factor genes may be due to the fitness cost associated with methicillin resistance.

Structural dynamics of the MecA-ClpC complex: a type II AAA+ protein unfolding machine.

Science.gov (United States)

Liu, Jing; Mei, Ziqing; Li, Ningning; Qi, Yutao; Xu, Yanji; Shi, Yigong; Wang, Feng; Lei, Jianlin; Gao, Ning

2013-06-14

The MecA-ClpC complex is a bacterial type II AAA(+) molecular machine responsible for regulated unfolding of substrates, such as transcription factors ComK and ComS, and targeting them to ClpP for degradation. The six subunits of the MecA-ClpC complex form a closed barrel-like structure, featured with three stacked rings and a hollow passage, where substrates are threaded and translocated through successive pores. Although the general concepts of how polypeptides are unfolded and translocated by internal pore loops of AAA(+) proteins have long been conceived, the detailed mechanistic model remains elusive. With cryoelectron microscopy, we captured four different structures of the MecA-ClpC complexes. These complexes differ in the nucleotide binding states of the two AAA(+) rings and therefore might presumably reflect distinctive, representative snapshots from a dynamic unfolding cycle of this hexameric complex. Structural analysis reveals that nucleotide binding and hydrolysis modulate the hexameric complex in a number of ways, including the opening of the N-terminal ring, the axial and radial positions of pore loops, the compactness of the C-terminal ring, as well as the relative rotation between the two nucleotide-binding domain rings. More importantly, our structural and biochemical data indicate there is an active allosteric communication between the two AAA(+) rings and suggest that concerted actions of the two AAA(+) rings are required for the efficiency of the substrate unfolding and translocation. These findings provide important mechanistic insights into the dynamic cycle of the MecA-ClpC unfoldase and especially lay a foundation toward the complete understanding of the structural dynamics of the general type II AAA(+) hexamers.

Carriage frequency, phenotypic, and genotypic characteristics of methicillin-resistant Staphylococcus aureus isolated from dental health-care personnel, patients, and environment.

Science.gov (United States)

Khairalla, Ahmed S; Wasfi, Reham; Ashour, Hossam M

2017-08-07

There is limited data on methicillin-resistant Staphylococcus aureus (MRSA) carriage in dental clinics. 1300 specimens from patients, health personnel, and environmental surfaces of a dental clinic in Egypt were tested for MRSA. Antibiotic susceptibility, biofilm formation, Staphylococcal protein A (spa) typing, SCCmec typing, and PCR-based assays were used to detect mecA, mecC, vanA, Panton-Valentine Leukocidin toxin (PVL), and toxic shock syndrome toxin-1 (tst) genes. Among 34 mecA-positive MRSA isolates, five (14.7%) were PVL-positive, seventeen (50%) were tst-positive, ten (29.4%) were vanA-positive, while none harboured mecC. MRSA hand carriage rates in patients, nurses, and dentists were 9.8%, 6.6%, and 5%. The respective nasal colonization rates were 11.1%, 6.7%, and 9.7%. 1.3% of the environmental isolates were MRSA-positive. Strong and moderate biofilm-forming isolates represented 23.5% and 29.4% of MRSA isolates. 24 MRSA isolates (70.6%) were multi-resistant and 18 (52.9%) harboured SCCmec IV. Among eight spa types, t223 (26.5%), t267 (23.5%), and t14339 (23.5%) were predominant. We noted an alarming genetic relatedness between 7 (20.6%) MRSA isolates and the epidemic EMRSA-15 clone, as well as a combined occurrence of tst and PVL in 3 (8.8%) isolates. Results suggest high MRSA pathogenicity in dental wards highlighting the need for more efficient surveillance/infection control strategies.

Dredging in Sediments Containing Munitions and Explosives of Concern (MEC)

National Research Council Canada - National Science Library

Welp, Timothy; Follett, George; Crull, Michelle; Pollock, Cheryl

2008-01-01

.... This report describes the different types of dredges and dredging projects that can encounter MEC, describes how these dredges' operational methodologies can be impacted by MEC, and summarizes past...

Changing epidemiology of methicillin-resistant Staphylococcus aureus in Iceland from 2000 to 2008: a challenge to current guidelines

DEFF Research Database (Denmark)

Holzknecht, B.J.; Hardardottir, H.; Haraldsson, Gustav Helgi

2010-01-01

and microbiological data of all MRSA patients from the years 2000 to 2008 were collected prospectively. Isolates were characterized by pulsed-field gel electrophoresis (PFGE), sequencing of the repeat region of the Staphylococcus protein A gene (spa typing), staphylococcal cassette chromosome mec (SCCmec) typing...... setting. However, MRSA in Iceland is now shifting into the community, challenging the current Icelandic guidelines, which are tailored to the health care system....

Genotyping of methicillin-resistant Staphylococcus aureus in the Sultan Qaboos University Hospital, Oman reveals the dominance of Panton–Valentine leucocidin-negative ST6-IV/t304 clone

Directory of Open Access Journals (Sweden)

E.E. Udo

2014-07-01

Full Text Available The objective of this study was to determine the prevalence and distribution of methicillin-resistant Staphylococcus aureus (MRSA genotypes circulating at a tertiary hospital in the Sultanate of Oman. A total of 79 MRSA isolates were obtained from different clinical samples and investigated using antibiogram, pulsed-field gel electrophoresis (PFGE, staphylococcal chromosome cassette mec (SCCmec, Spa typing and multilocus sequence typing (MLST. The isolates were susceptible to linezolid, vancomycin, teicoplanin, tigecycline and mupirocin but were resistant to tetracycline (30.4%, erythromycin (26.6%, clindamycin (24.1%, trimethoprim (19.0%, ciprofloxacin (17.7%, fusidic acid (15.2% and gentamicin (12.7%. Molecular typing revealed 19 PFGE patterns, 26 Spa types and 21 sequence types. SCCmec-IV (86.0% was the dominant SCCmec type, followed by SCCmec-V (10.1%. SCCmec-III (2.5% and SCCmec-II (1.3% were less common. ST6-IV/t304 (n = 30 and ST1295-IV/t690 (n = 12 were the dominant genotypes followed by ST772-V/t657 (n = 5, ST30-IV/t019/t021 (n = 5, ST22-IV/t852 (n = 4, ST80-IV/t044 (n = 3 and 18 single genotypes that were isolated sporadically. On the basis of SCCmec typing and MLST, 91.2% of the isolates were classified as community-associated MRSA and 8.8% of the isolates (consisting of four ST22-IV/t852, one ST239-III/t632, one ST5-III/t311 and one ST5-II/t003 were classified as healthcare-associated MRSA. The study has revealed the dominance of a Panton–Valentine leucocidin-negative ST6-IV/t304 clone and provided insights into the distribution of antibiotic resistance in MRSA at the tertiary hospital in Oman. It also highlights the importance of surveillance in detecting the emergence of new MRSA clones in a healthcare facility.

The dissemination of ST80-SCCmec-IV community-associated methicillin resistant Staphylococcus aureus clone in Kuwait hospitals

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Sarkhoo Eiman

2010-11-01

Full Text Available Abstract Background Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA is a global healthcare problem. The purpose of this study was to characterize CA-MRSA clones and their distribution in Kuwait hospitals. Methods In total, 135 CA-MRSA isolates, carrying the SCCmec IV or V genetic elements, isolated in eight hospitals were characterized using antibiogram, pulsed-field gel electrophoresis, multilocus sequence typing, and carriage of genes for Panton-Valentine Leukocidin (PVL, capsular polysaccharides types (cap 5 and 8, accessory genes regulators (agr, Staphylococcal enterotoxins (SE and toxic shock syndrome toxin 1 (tst. Results They were susceptible to vancomycin, teicoplanin and linezolid but resistant to kanamycin (62%, fusidic acid (42.2%, tetracycline (39.3%, erythromycin and clindamycin (21.5%, gentamicin (5.9%, streptomycin (6.7%, trimethoprim (5.9%, mupirocin (6.6% and cadmium acetate (82.2%. They consisted of 10 pulsotypes with the majority belonging to PFGE type I (51.1%, type II (22.2%, type IV (13.3% and type III (3.7%. They belonged to 10 sequence types (ST comprising ST80 (51.1%, ST30 (22.2%, ST5 (14.1%, ST1 (4.45, ST6 (3.7%, ST88 (1.5%, ST834 (1.5%, ST8 (0.7%, ST46 (0.7% and ST950 (0.7%. Genes for PVL, cap 8, cap 5 and agr III, agr I and agr II were detected in 61.5%, 77.3%, 20.7% and 62.2%, 17% and 8.1% of the isolates respectively. Nine (6.7% isolates contained tst while 103 isolates were positive for SE genes with sei (63.0%, seg (41.5% and sed (29.6% as the common SE genes. Conclusions ST80-SCCmecIV was the most common CA-MRSA clone in Kuwait hospitals presenting new challenges for infection control.

Detection of diverse genotypes of Methicillin-resistant Staphylococcus aureus from hospital personnel and the environment in Armenia

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Hermine V. Mkrtchyan

2017-02-01

Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA is a public health concern internationally. Studies examining a range of cohorts have been reported from various regions of the world, but little is known about the molecular epidemiology of MRSA in Armenia. Methods Between May and September 2013, twenty isolates of methicillin-resistant Staphylococcus aureus (MRSA; mecA positive were recovered from hospital personnel (n = 10; 9 females, 1 male and environmental sites (n = 10 in the maternity ward of one of the teaching hospitals in Armenia. Results Multi-locus sequence type clonal complex (MLST-CC assignments inferred from spa typing data revealed the majority belonged to 3 pandemic lineages of MRSA including: t008-CC8-SCCmecV (n = 10; 7 from personnel; t021-CC30-SCCmecIV (n = 5; all environmental; and t1523-CC45 (n = 2; 1 from personnel, one harboured SCCmecV the other was SCCmec non-typable. The remainder identified as belonging to genotype t364-CC182, both of which harboured a novel SCCmec cassette with kdp, rif5, ccrB2 and ccrC detected by PCR (both from personnel; and t325-CC88-SCCmecIV (n = 1; environmental. All MRSA were negative for the Panton-Valentine Leukocidin (PVL locus and three CC8 strains were positive for the arginine catabolic element (ACME. Conclusions In this small study, we report for the first time of the occurrence of diverse MRSA genotypes belonging to both pandemic and more sporadic international clones in Armenia harbouring the smaller SCCmec types and/or ACME, both of which have been associated with strain fitness. Further surveillance is warranted to better understand the prevalence, clinical and molecular epidemiology of MRSA throughout Armenia.

Molecular investigation of Staphylococcus aureus isolated from the patients, personnel, air and environment of an ICU in a hospital in Tehran.

Science.gov (United States)

Mirzaii, Mehdi; Emaneini, Mohammad; Jabalameli, Fereshteh; Halimi, Shahnaz; Taherikalani, Morovat

2015-01-01

The aim of this study was to determine the prevalence and characteristics of Staphylococcus aureus isolates from the patients, staff, air and environments of an ICU in a hospital in Tehran. During this study, 37 S. aureus isolates were collected and analyzed via the spa typing method. Of the 37 S. aureus isolates, 35 (94%) were methicillin resistant (MRSA), 28 (76%) were identified as SCCmec types III or IIIA, four (10%) were identified as SCCmec types I or IA and three (8%) were identified a SCCmec type IV. All of the MRSA isolates were resistant to oxacillin and contained mecA. The isolates were all spa typed and found to comprise 11 spa types, including t7688, t7689, and t7789, which have not previously been reported. The spa type t7688 was isolated from the hands of two ICU personnel. The spa type t7689 was observed among five isolates from the air and the environment. The spa type t7789 was observed among three isolates from the patients, ventilators and the air. The majority of the isolates (43%) belonged to spa types t030 and t037. Our results revealed that MRSA strains that were isolated from the air, the environment of the ICU and the patients who were colonized or infected with MRSA often exhibited the same spa and SCCmec types. These results also reveal that the isolates from the patients and environment were usually indistinguishable. Copyright © 2014 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

Molecular epidemiology and antimicrobial resistance of methicillin-resistant Staphylococcus aureus bloodstream isolates in Taiwan, 2010.

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Chih-Jung Chen

Full Text Available The information of molecular characteristics and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus (MRSA is essential for control and treatment of diseases caused by this medically important pathogen. A total of 577 clinical MRSA bloodstream isolates from six major hospitals in Taiwan were determined for molecular types, carriage of Panton-Valentine leukocidin (PVL and sasX genes and susceptibilities to 9 non-beta-lactam antimicrobial agents. A total of 17 genotypes were identified in 577 strains by pulsotyping. Five major pulsotypes, which included type A (26.2%, belonging to sequence type (ST 239, carrying type III staphylococcal chromosomal cassette mec (SCCmec, type F (18.9%, ST5-SCCmecII, type C (18.5%, ST59-SCCmecIV, type B (12.0%, ST239-SCCmecIII and type D (10.9%, ST59-SCCmecVT/IV, prevailed in each of the six sampled hospitals. PVL and sasX genes were respectively carried by ST59-type D strains and ST239 strains with high frequencies (93.7% and 99.1%, respectively but rarely detected in strains of other genotypes. Isolates of different genotypes and from different hospitals exhibited distinct antibiograms. Multi-resistance to ≥3 non-beta-lactams was more common in ST239 isolates (100% than in ST5 isolates (97.2%, P = 0.0347 and ST59 isolates (8.2%, P<0.0001. Multivariate analysis further indicated that the genotype, but not the hospital, was an independent factor associated with muti-resistance of the MRSA strains. In conclusion, five common MRSA clones with distinct antibiograms prevailed in the major hospitals in Taiwan in 2010. The antimicrobial susceptibility pattern of invasive MRSA was mainly determined by the clonal distribution.

Study of methicillin resistant Staphylococcus aureus (MRSA) in Danish pigs at slaughter and in imported retail meat reveals a novel MRSA type in slaughter pigs

DEFF Research Database (Denmark)

Agersø, Yvonne; Hasman, Henrik; Cavaco, Lina M.

2012-01-01

Methicillin-resistant Staphylococcus aureus (MRSA), especially CC398, have emerged in livestock worldwide. We investigated the occurrence of MRSA in pigs at slaughter and in retail meat. During 2009, nasal swabs (n=789) were taken from pigs at slaughter. Moreover, 866 meat samples [Danish: pork...... (153), broiler meat (121), beef (142) and; imported: pork (173), broiler meat (193), and beef (84)] were randomly collected in retail stores and outlets. MRSA was isolated from nasal swabs or from meat samples after preenrichment (Mueller Hinton broth with 6.5% NaCl), selective enrichment (tryptone...... soya broth with 4mg/L cefoxitine and 75mg/L aztreonam) and selective plating on Brilliance Chromogenic MRSA agar. The presence of mecA was confirmed by PCR and the MRSA isolates were spa typed. Novel MRSA spa types were characterized by MLST, PFGE and SCCmec typing. Thirteen percent (101...

Prevalence and characterisation of Staphylococcus aureus causing community-acquired skin and soft tissue infections on Java and Bali, Indonesia.

Science.gov (United States)

Santosaningsih, Dewi; Santoso, Sanarto; Setijowati, Nanik; Rasyid, Harun A; Budayanti, Nyoman S; Suata, Ketut; Widhyatmoko, Dicky B; Purwono, Priyo B; Kuntaman, Kuntaman; Damayanti, Damayanti; Prakoeswa, Cita R S; Laurens, Mitchell; van Nierop, Josephine W I; Nanninga, Geraldine L; Oudenes, Neline; de Regt, Michelle; Snijders, Susan V; Verbrugh, Henri A; Severin, Juliëtte A

2018-01-01

To define the role of Staphylococcus aureus in community settings among patients with skin and soft tissue infections (SSTI) in Indonesia. Staphylococcus aureus were cultured from anterior nares, throat and wounds of 567 ambulatory patients presenting with SSTI. The mecA gene and genes encoding Panton-Valentine leukocidin (PVL; lukF-PV and lukS-PV) and exfoliative toxin (ET; eta and etb) were determined by PCR. Clonal relatedness among methicillin-resistant S. aureus (MRSA) and PVL-positive S. aureus was analysed using multilocus variable-number tandem-repeat analysis (MLVA) typing, and multilocus sequence typing (MLST) for a subset of isolates. Staphylococcal cassette chromosome mec (SCCmec) was determined for all MRSA isolates. Moreover, determinants for S. aureus SSTI, and PVL/ET-positive vs PVL/ET-negative S. aureus were assessed. Staphylococcus aureus were isolated from SSTI wounds of 257 (45.3%) patients, eight (3.1%) of these were MRSA. Genes encoding PVL and ETs were detected in 21.8% and 17.5% of methicillin-susceptible S. aureus (MSSA), respectively. PVL-positive MRSA was not detected. Nasopharyngeal S. aureus carriage was an independent determinant for S. aureus SSTI (odds ratio [OR] 1.8). Primary skin infection (OR 5.4) and previous antibiotic therapy (OR 3.5) were associated with PVL-positive MSSA. Primary skin infection (OR 2.2) was the only factor associated with ET-positive MSSA. MLVA typing revealed two more prevalent MSSA clusters. One ST1-MRSA-SCCmec type IV isolate and a cluster of ST239-MRSA-SCCmec type III were found. Community-acquired SSTI in Indonesia was frequently caused by PVL-positive MSSA, and the hospital-associated ST239-MRSA may have spread from the hospital into the community. © 2017 John Wiley & Sons Ltd.

Complete Circular Genome Sequence of Successful ST8/SCCmecIV Community-Associated Methicillin-Resistant Staphylococcus aureus (OC8 in Russia: One-Megabase Genomic Inversion, IS256's Spread, and Evolution of Russia ST8-IV.

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Tsai-Wen Wan

Full Text Available ST8/SCCmecIV community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA has been a common threat, with large USA300 epidemics in the United States. The global geographical structure of ST8/SCCmecIV has not yet been fully elucidated. We herein determined the complete circular genome sequence of ST8/SCCmecIVc strain OC8 from Siberian Russia. We found that 36.0% of the genome was inverted relative to USA300. Two IS256, oppositely oriented, at IS256-enriched hot spots were implicated with the one-megabase genomic inversion (MbIN and vSaβ split. The behavior of IS256 was flexible: its insertion site (att sequences on the genome and junction sequences of extrachromosomal circular DNA were all divergent, albeit with fixed sizes. A similar multi-IS256 system was detected, even in prevalent ST239 healthcare-associated MRSA in Russia, suggesting IS256's strong transmission potential and advantage in evolution. Regarding epidemiology, all ST8/SCCmecIVc strains from European, Siberian, and Far Eastern Russia, examined had MbIN, and geographical expansion accompanied divergent spa types and resistance to fluoroquinolones, chloramphenicol, and often rifampicin. Russia ST8/SCCmecIVc has been associated with life-threatening infections such as pneumonia and sepsis in both community and hospital settings. Regarding virulence, the OC8 genome carried a series of toxin and immune evasion genes, a truncated giant surface protein gene, and IS256 insertion adjacent to a pan-regulatory gene. These results suggest that unique single ST8/spa1(t008/SCCmecIVc CA-MRSA (clade, Russia ST8-IVc emerged in Russia, and this was followed by large geographical expansion, with MbIN as an epidemiological marker, and fluoroquinolone resistance, multiple virulence factors, and possibly a multi-IS256 system as selective advantages.

Complete Circular Genome Sequence of Successful ST8/SCCmecIV Community-Associated Methicillin-Resistant Staphylococcus aureus (OC8) in Russia: One-Megabase Genomic Inversion, IS256's Spread, and Evolution of Russia ST8-IV.

Science.gov (United States)

Wan, Tsai-Wen; Khokhlova, Olga E; Iwao, Yasuhisa; Higuchi, Wataru; Hung, Wei-Chun; Reva, Ivan V; Singur, Olga A; Gostev, Vladimir V; Sidorenko, Sergey V; Peryanova, Olga V; Salmina, Alla B; Reva, Galina V; Teng, Lee-Jene; Yamamoto, Tatsuo

2016-01-01

ST8/SCCmecIV community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been a common threat, with large USA300 epidemics in the United States. The global geographical structure of ST8/SCCmecIV has not yet been fully elucidated. We herein determined the complete circular genome sequence of ST8/SCCmecIVc strain OC8 from Siberian Russia. We found that 36.0% of the genome was inverted relative to USA300. Two IS256, oppositely oriented, at IS256-enriched hot spots were implicated with the one-megabase genomic inversion (MbIN) and vSaβ split. The behavior of IS256 was flexible: its insertion site (att) sequences on the genome and junction sequences of extrachromosomal circular DNA were all divergent, albeit with fixed sizes. A similar multi-IS256 system was detected, even in prevalent ST239 healthcare-associated MRSA in Russia, suggesting IS256's strong transmission potential and advantage in evolution. Regarding epidemiology, all ST8/SCCmecIVc strains from European, Siberian, and Far Eastern Russia, examined had MbIN, and geographical expansion accompanied divergent spa types and resistance to fluoroquinolones, chloramphenicol, and often rifampicin. Russia ST8/SCCmecIVc has been associated with life-threatening infections such as pneumonia and sepsis in both community and hospital settings. Regarding virulence, the OC8 genome carried a series of toxin and immune evasion genes, a truncated giant surface protein gene, and IS256 insertion adjacent to a pan-regulatory gene. These results suggest that unique single ST8/spa1(t008)/SCCmecIVc CA-MRSA (clade, Russia ST8-IVc) emerged in Russia, and this was followed by large geographical expansion, with MbIN as an epidemiological marker, and fluoroquinolone resistance, multiple virulence factors, and possibly a multi-IS256 system as selective advantages.

Complete Circular Genome Sequence of Successful ST8/SCCmecIV Community-Associated Methicillin-Resistant Staphylococcus aureus (OC8) in Russia: One-Megabase Genomic Inversion, IS256’s Spread, and Evolution of Russia ST8-IV

Science.gov (United States)

Wan, Tsai-Wen; Higuchi, Wataru; Hung, Wei-Chun; Reva, Ivan V.; Singur, Olga A.; Gostev, Vladimir V.; Sidorenko, Sergey V.; Peryanova, Olga V.; Salmina, Alla B.; Reva, Galina V.; Teng, Lee-Jene; Yamamoto, Tatsuo

2016-01-01

ST8/SCCmecIV community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been a common threat, with large USA300 epidemics in the United States. The global geographical structure of ST8/SCCmecIV has not yet been fully elucidated. We herein determined the complete circular genome sequence of ST8/SCCmecIVc strain OC8 from Siberian Russia. We found that 36.0% of the genome was inverted relative to USA300. Two IS256, oppositely oriented, at IS256-enriched hot spots were implicated with the one-megabase genomic inversion (MbIN) and vSaβ split. The behavior of IS256 was flexible: its insertion site (att) sequences on the genome and junction sequences of extrachromosomal circular DNA were all divergent, albeit with fixed sizes. A similar multi-IS256 system was detected, even in prevalent ST239 healthcare-associated MRSA in Russia, suggesting IS256’s strong transmission potential and advantage in evolution. Regarding epidemiology, all ST8/SCCmecIVc strains from European, Siberian, and Far Eastern Russia, examined had MbIN, and geographical expansion accompanied divergent spa types and resistance to fluoroquinolones, chloramphenicol, and often rifampicin. Russia ST8/SCCmecIVc has been associated with life-threatening infections such as pneumonia and sepsis in both community and hospital settings. Regarding virulence, the OC8 genome carried a series of toxin and immune evasion genes, a truncated giant surface protein gene, and IS256 insertion adjacent to a pan-regulatory gene. These results suggest that unique single ST8/spa1(t008)/SCCmecIVc CA-MRSA (clade, Russia ST8-IVc) emerged in Russia, and this was followed by large geographical expansion, with MbIN as an epidemiological marker, and fluoroquinolone resistance, multiple virulence factors, and possibly a multi-IS256 system as selective advantages. PMID:27741255

Clinical and molecular features of methicillin-resistant, coagulase-negative staphylococci of pets and horses.

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Kern, Andrea; Perreten, Vincent

2013-06-01

To determine the antibiotic resistance and fingerprint profiles of methicillin-resistant coagulase-negative staphylococci (MRCoNS) from animal infections among different practices and examine the history of antibiotic treatment. Isolates were identified by mass spectrometry and tested for antimicrobial resistance by broth dilution, microarrays and sequence analysis of the topoisomerases. Diversity was assessed by PFGE, icaA PCR and staphylococcal cassette chromosome mec (SCCmec), arginine catabolic mobile element (ACME) and multilocus sequence typing. Clinical records were examined retrospectively. MRCoNS were identified as Staphylococcus epidermidis (n=20), Staphylococcus haemolyticus (n=17), Staphylococcus hominis (n=3), Staphylococcus capitis (n=1), Staphylococcus cohnii (n=1) and Staphylococcus warneri (n=1). PFGE identified one clonal lineage in S. hominis isolates and several in S. haemolyticus and S. epidermidis. Fourteen sequence types were identified in S. epidermidis, with sequence type 2 (ST2) and ST5 being predominant. Ten isolates contained SCCmec IV, seven contained SCCmec V and the others were non-typeable. ACMEs were detected in 11 S. epidermidis isolates. One S. hominis and 10 S. epidermidis isolates were icaA positive. In addition to mecA-mediated β-lactam resistance, the most frequent resistance was to gentamicin/kanamycin [aac(6')-Ie-aph(2')-Ia, aph(3')-III] (n=34), macrolides/lincosamides [erm(C), erm(A), msr, lnu(A)] (n=31), tetracycline [tet(K)] (n=22), streptomycin [str, ant(6)-Ia] (n=20), trimethoprim [dfr(A), dfr(G)] (n=17), sulfamethoxazole (n = 34) and fluoroquinolones [amino acid substitutions in GyrA and GrlA] (n=30). Clinical data suggest selection through multiple antibiotic courses and emphasize the importance of accurate diagnosis and antibiograms. MRCoNS from animal infection sites are genetically heterogeneous multidrug-resistant strains that represent a new challenge in the prevention and therapy of infections in veterinary

Occurrence and molecular characteristics of methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus pseudintermedius in an academic veterinary hospital.

Science.gov (United States)

Ishihara, Kanako; Shimokubo, Natsumi; Sakagami, Akie; Ueno, Hiroshi; Muramatsu, Yasukazu; Kadosawa, Tsuyoshi; Yanagisawa, Chie; Hanaki, Hideaki; Nakajima, Chie; Suzuki, Yasuhiko; Tamura, Yutaka

2010-08-01

Recently, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) have been increasingly isolated from veterinarians and companion animals. With a view to preventing the spread of MRSA and MRSP, we evaluated the occurrence and molecular characteristics of each in a veterinary college. MRSA and MRSP were isolated from nasal samples from veterinarians, staff members, and veterinary students affiliated with a veterinary hospital. Using stepwise logistic regression, we identified two factors associated with MRSA carriage: (i) contact with an identified animal MRSA case (odds ratio [OR], 6.9; 95% confidence interval [95% CI], 2.2 to 21.6) and (ii) being an employee (OR, 6.2; 95% CI, 2.0 to 19.4). The majority of MRSA isolates obtained from individuals affiliated with the veterinary hospital and dog patients harbored spa type t002 and a type II staphylococcal cassette chromosome mec (SCCmec), similar to the hospital-acquired MRSA isolates in Japan. MRSA isolates harboring spa type t008 and a type IV SCCmec were obtained from one veterinarian on three different sampling occasions and also from dog patients. MRSA carriers can also be a source of MRSA infection in animals. The majority of MRSP isolates (85.2%) carried hybrid SCCmec type II-III, and almost all the remaining MRSP isolates (11.1%) carried SCCmec type V. MRSA and MRSP were also isolated from environmental samples collected from the veterinary hospital (5.1% and 6.4%, respectively). The application of certain disinfection procedures is important for the prevention of nosocomial infection, and MRSA and MRSP infection control strategies should be adopted in veterinary medical practice.

Technical support document for proposed 1994 revision of the MEC thermal envelope requirements

Energy Technology Data Exchange (ETDEWEB)

Conner, C.C.; Lucas, R.G.

1994-03-01

This report documents the development of the proposed revision of the Council of American Building Officials` (CABO) 1994 supplement to the 1993 Model Energy Code (MEC) building thermal envelope requirements for maximum component U{sub 0}-value. The 1994 amendments to the 1993 MEC were established in last year`s code change cycle and did not change the envelope requirements. The research underlying the proposed MEC revision was conducted by Pacific Northwest Laboratory (PNL) for the US Department of Energy (DOE) Building Energy Standards program. The goal of this research was to develop revised guidelines based on an objective methodology that determines the most cost-effective (least total cost) combination of energy conservation measures (ECMs) (insulation levels and window types) for residential buildings. This least-cost set of ECMs was used as a basis for proposing revised MEC maximum U{sub 0}-values (thermal transmittances). ECMs include window types (for example, double-pane vinyl) and insulation levels (for example, R-19) for ceilings, walls, and floors.

Research Paper ISSN: 2006-0165©2009

African Journals Online (AJOL)

altered PBP2a by latex agglutination test and β-lactamase production/hyper ... Staphylococcal cassette chromosome mec (SCCmec) (Lowy, 2003; ... resistance and the slow growth of the resistant bacteria can make detection difficult. Detection ...

Environmental methicillin-resistant Staphylococcus aureus in a veterinary teaching hospital during a nonoutbreak period.

Science.gov (United States)

Hoet, Armando E; Johnson, Amanda; Nava-Hoet, Rocio C; Bateman, Shane; Hillier, Andrew; Dyce, John; Gebreyes, Wondwossen A; Wittum, Thomas E

2011-06-01

Concurrent to reports of zoonotic and nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary settings, recent evidence indicates that the environment in veterinary hospitals may be a potential source of MRSA. The present report is a cross-sectional study to determine the prevalence of MRSA on specific human and animal contact surfaces at a large veterinary hospital during a nonoutbreak period. A total of 156 samples were collected using Swiffers(®) or premoistened swabs from the small animal, equine, and food animal sections. MRSA was isolated and identified by pre-enrichment culture and standard microbiology procedures, including growth on Mueller-Hinton agar supplemented with NaCl and oxacillin, and by detection of the mecA gene. Staphylococcal chromosome cassette mec (SCCmec) typing and pulsed-field gel electrophoresis profile were also determined. MRSA was detected in 12% (19/157) of the hospital environments sampled. The prevalence of MRSA in the small animal, equine, and food animal areas were 16%, 4%, and 0%, respectively. Sixteen of the MRSA isolates from the small animal section were classified as USA100, SCCmec type II, two of which had pulsed-field gel electrophoresis pattern that does not conform to any known type. The one isolate obtained from the equine section was classified as USA500, SCCmec type IV. The molecular epidemiological analysis revealed a very diverse population of MRSA isolates circulating in the hospital; however, in some instances, multiple locations/surfaces, not directly associated, had the same MRSA clone. No significant difference was observed between animal and human contact surfaces in regard to prevalence and type of isolates. Surfaces touched by multiple people (doors) and patients (carts) were frequently contaminated with MRSA. The results from this study indicate that MRSA is present in the environment even during nonoutbreak periods. This study also identified specific surfaces in a

Distribution of the ACME-arcA gene among meticillin-resistant Staphylococcus haemolyticus and identification of a novel ccr allotype in ACME-arcA-positive isolates.

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Pi, Borui; Yu, Meihong; Chen, Yagang; Yu, Yunsong; Li, Lanjuan

2009-06-01

The aim of this study was to investigate the prevalence and characteristics of ACME (arginine catabolic mobile element)-arcA-positive isolates among meticillin-resistant Staphylococcus haemolyticus (MRSH). ACME-arcA, native arcA and SCCmec elements were detected by PCR. Susceptibilities to 10 antimicrobial agents were compared between ACME-arcA-positive and -negative isolates by chi-square test. PFGE was used to investigate the clonal relatedness of ACME-arcA-positive isolates. The phylogenetic relationships of ACME-arcA and native arcA were analysed using the neighbour-joining methods of mega software. A total of 42 (47.7 %) of 88 isolates distributed in 13 PFGE types were positive for the ACME-arcA gene. There were no significant differences in antimicrobial susceptibility between ACME-arcA-positive and -negative isolates. A novel ccr allotype (ccrAB(SHP)) was identified in ACME-arcA-positive isolates. Among 42 ACME-arcA-positive isolates: 8 isolates harboured SCCmec V, 8 isolates harboured class C1 mec complex and ccrAB(SHP); 22 isolates harbouring class C1 mec complex and 4 isolates harbouring class C2 mec complex were negative for all known ccr allotypes. The ACME-arcA-positive isolates were first found in MRSH with high prevalence and clonal diversity, which suggests a mobility of ACME within MRSH. The results from this study revealed that MRSH is likely to be one of the potential reservoirs of ACME for Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus emerged long before the introduction of methicillin into clinical practice.

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Harkins, Catriona P; Pichon, Bruno; Doumith, Michel; Parkhill, Julian; Westh, Henrik; Tomasz, Alexander; de Lencastre, Herminia; Bentley, Stephen D; Kearns, Angela M; Holden, Matthew T G

2017-07-20

The spread of drug-resistant bacterial pathogens poses a major threat to global health. It is widely recognised that the widespread use of antibiotics has generated selective pressures that have driven the emergence of resistant strains. Methicillin-resistant Staphylococcus aureus (MRSA) was first observed in 1960, less than one year after the introduction of this second generation beta-lactam antibiotic into clinical practice. Epidemiological evidence has always suggested that resistance arose around this period, when the mecA gene encoding methicillin resistance carried on an SCCmec element, was horizontally transferred to an intrinsically sensitive strain of S. aureus. Whole genome sequencing a collection of the first MRSA isolates allows us to reconstruct the evolutionary history of the archetypal MRSA. We apply Bayesian phylogenetic reconstruction to infer the time point at which this early MRSA lineage arose and when SCCmec was acquired. MRSA emerged in the mid-1940s, following the acquisition of an ancestral type I SCCmec element, some 14 years before the first therapeutic use of methicillin. Methicillin use was not the original driving factor in the evolution of MRSA as previously thought. Rather it was the widespread use of first generation beta-lactams such as penicillin in the years prior to the introduction of methicillin, which selected for S. aureus strains carrying the mecA determinant. Crucially this highlights how new drugs, introduced to circumvent known resistance mechanisms, can be rendered ineffective by unrecognised adaptations in the bacterial population due to the historic selective landscape created by the widespread use of other antibiotics.

Directory of Open Access Journals (Sweden)

Cristina Motta Ferreira

2013-04-01

Full Text Available Methicillin-resistant Staphylococcus remains a severe public health problem worldwide. This research was intended to identify the presence of methicillin-resistant coagulase-negative staphylococci clones and their staphylococcal cassette chromosome mec (SCCmec-type isolate from patients with haematologic diseases presenting bacterial infections who were treated at the Blood Bank of the state of Amazonas in Brazil. Phenotypic and genotypic tests, such as SCCmec types and multilocus sequence typing (MLST, were developed to detect and characterise methicillin-resistant isolates. A total of 26 Gram-positive bacteria were isolated, such as: Staphylococcus epidermidis (8/27, Staphylococcus intermedius (4/27 and Staphylococcus aureus (4/27. Ten methicillin-resistant staphylococcal isolates were identified. MLST revealed three different sequence types: S. aureus ST243, S. epidermidis ST2 and a new clone of S. epidermidis, ST365. These findings reinforce the potential of dissemination presented by multi-resistant Staphylococcus and they suggest the introduction of monitoring actions to reduce the spread of pathogenic clonal lineages of S. aureus and S. epidermidis to avoid hospital infections and mortality risks.

Comparative genomics and drug resistance of a geographic variant of ST239 methicillin-resistant Staphylococcus aureus emerged in Russia.

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Tatsuo Yamamoto

Full Text Available Two distinct classes of methicillin-resistant Staphylococcus aureus (MRSA are spreading in hospitals (as hospital-acquired MRSA, HA-MRSA and in the community (as community-acquired MRSA, CA-MRSA. Multilocus sequence type (ST 239 MRSA, one of the most worldwide-disseminated lineages, has been noted as a representative HA-MRSA. Here, we isolated ST239 MRSA (spa type 3 [t037] and staphylococcal cassette chromosome mec [SCCmec] type III.1.1.1 and its novel variant with ST239/spa351 (t030/SCCmecIII.1.1.4 (SCCmecIII(R not only from hospitals but also from patients with urethritis in the community in Russia. The Russian variant (strain 16K possessed a hybrid genome consisting of CC8 and CC30, similar to the ST239/spa3/SCCmecIII.1.1.1 HA-MRSA (TW20 genome, but with marked diversity. The 16K' CC30 section had SCCmecIII(R carrying the dcs-carrying unit (which corresponded to the SCCmecIVc J3 joining region of ST30 CA-MRSA, lacked SCCmercury, and possessed a novel mobile element structure (MES16K carrying the ccrC-carrying unit (with the recombinase gene ccrC1 allele 3 and drug resistance tranposons. The Russian variant included strains with a high ability to transfer its multiple drug resistance by conjugation; e.g., for strain 16K, the transfer frequency of a chloramphenicol resistance plasmid (p16K-1 with 2.9 kb in size reached 1.4×10(-2, followed by Tn554 conjugative transfer at 3.6×l0(-4. The Russian variant, which has been increasing recently, included divergent strains with different plasmid patterns and pulsed field gel electrophoresis profiles. The data demonstrate the alternative nature of ST239 MRSA as CA-MRSA and also as a drug resistance disseminator, and its micro but dynamic evolution in Russia.

Copresence of tet(K) and tet(M) in Livestock-Associated Methicillin-Resistant Staphylococcus aureus Clonal Complex 398 Is Associated with Increased Fitness during Exposure to Sublethal Concentrations of Tetracycline

DEFF Research Database (Denmark)

Larsen, Jesper; Clasen, Julie; Hansen, Julie Elvekjær

2016-01-01

The tetracycline resistance gene tet(K) was shown to be integrated within the predominant staphylococcal cassette chromosome mec (SCCmec) element of Danish livestock-associated methicillin-resistant Staphylococcus aureus CC398 (LA-MRSA CC398). These LA-MRSA CC398 isolates already possessed tet(M)......(M), but the acquisition of tet(K) significantly improved their fitness at sublethal concentrations of tetracycline. Because tet(K) is genetically linked to SCCmec, the use of tetracycline in food animals may have contributed to the successful spread of LA-MRSA CC398....

Hospital clones of methicillin-resistant Staphylococcus aureus are carried by medical students even before healthcare exposure

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Ido Orlin

2017-01-01

Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA strains are prevalent in healthcare and the community. Few studies have examined MRSA carriage among medical students. The aim of this study is to examine Staphylococcus aureus (SA carriage, and particular MRSA, over time in cohort medical students Methods Prospective collection of nasal swabs from medical students in Israel and assessment of SA carriage. Three samples were taken per student in preclinical and clinical parts of studies. Antibiotic susceptibilities were recorded and MRSA typing was performed by staphylococcal cassette chromosome mec (SCCmec types, Panton Valentine Leukocidin (PVL encoding genes, and spa types. Clonality was assessed by pulsed-field gel electrophoresis. Results Among 58 students, SA carriage rates increased from 33% to 38% to 41% at baseline (preclinical studies, 13 and 19 months (clinical studies, respectively (p = 0.07. Methicillin-susceptible SA (MSSA carriage increased in the clinical studies period (22 to 41%, p = 0.01. Overall, seven students (12% carried 13 MRSA isolates. MRSA isolates were PVL negative and were characterized as SCCmecII-t002, SCCmecIV-t032, or t12435 with untypable SCCmec. MRSA carriage during the pre-clinical studies was evident in 4/7 students. Two students carried different MRSA clones at various times and persistent MRSA carriage was noted in one student. Simultaneous carriage of MRSA and MSSA was not detected. Conclusions MSSA carriage increased during the clinical part of studies in Israeli medical students. Compared with previous reports, higher rates of MRSA carriage were evident. MRSA strains were genotypically similar to Israeli healthcare-associated clones; however, carriage occurred largely before healthcare exposure, implying community-acquisition of hospital strains.

Molecular and Phenotypic Characterization of Staphylococcus epidermidis Isolates from Healthy Conjunctiva and a Comparative Analysis with Isolates from Ocular Infection.

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Luis A Flores-Páez

Full Text Available Staphylococcus epidermidis is a common commensal of healthy conjunctiva and it can cause endophthalmitis, however its presence in conjunctivitis, keratitis and blepharitis is unknown. Molecular genotyping of S. epidermidis from healthy conjunctiva could provide information about the origin of the strains that infect the eye. In this paper two collections of S. epidermidis were used: one from ocular infection (n = 62, and another from healthy conjunctiva (n = 45. All isolates were genotyped by pulsed field gel electrophoresis (PFGE, multilocus sequence typing (MLST, staphylococcal cassette chromosome mec (SCCmec, detection of the genes icaA, icaD, IS256 and polymorphism type of agr locus. The phenotypic data included biofilm production and antibiotic resistance. The results displayed 61 PFGE types from 107 isolates and they were highly discriminatory. MLST analysis generated a total of 25 STs, of which 11 STs were distributed among the ocular infection isolates and lineage ST2 was the most frequent (48.4%, while 14 STs were present in the healthy conjunctiva isolates and lineage ST5 was the most abundant (24.4%. By means of a principal coordinates analysis (PCoA and a discriminant analysis (DA it was found that ocular infection isolates had as discriminant markers agr III or agr II, SCCmec V or SCCmec I, mecA gene, resistance to tobramycin, positive biofilm, and IS256+. In contrast to the healthy conjunctiva isolates, the discriminating markers were agr I, and resistance to chloramphenicol, ciprofloxacin, gatifloxacin and oxacillin. The discriminant biomarkers of ocular infection were examined in healthy conjunctiva isolates, and it was found that 3 healthy conjunctiva isolates [two with ST2 and another with ST9] (3/45, 6.66% had similar genotypic and phenotypic characteristics to ocular infection isolates, therefore a small population from healthy conjunctiva could cause an ocular infection. These data suggest that the healthy conjunctiva

Disease: H01409 [KEGG MEDICUS

Lifescience Database Archive (English)

Full Text Available H01409 Methicillin-sensitive Staphylococcus aureus (MSSA) infection Staphylococcus... of the human population. Methicillin-resistant S. aureus (MRSA) is known to have evolved from methicillin-s...e mec (SCCmec) element which includes the mecA gene coding for resistance to the antibiotic methicillin. A h...ighly cytotoxic and clinically virulent methicillin-sensitive strain, S. aureus strain 6850 is a well-charac... ... Complete Genome Sequence of Staphylococcus aureus 6850, a Highly Cytotoxic and Clinically Virulent Methic

Reduced susceptibility to vancomycin and biofilm formation in methicillin-resistant Staphylococcus epidermidis isolated from blood cultures

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Luiza Pinheiro

2014-11-01

Full Text Available This study aimed to correlate the presence of ica genes, biofilm formation and antimicrobial resistance in 107 strains of Staphylococcus epidermidis isolated from blood cultures. The isolates were analysed to determine their methicillin resistance, staphylococcal cassette chromosome mec (SCCmec type, ica genes and biofilm formation and the vancomycin minimum inhibitory concentration (MIC was measured for isolates and subpopulations growing on vancomycin screen agar. The mecA gene was detected in 81.3% of the S. epidermidis isolated and 48.2% carried SCCmec type III. The complete icaADBC operon was observed in 38.3% of the isolates; of these, 58.5% produced a biofilm. Furthermore, 47.7% of the isolates grew on vancomycin screen agar, with an increase in the MIC in 75.9% of the isolates. Determination of the MIC of subpopulations revealed that 64.7% had an MIC ≥ 4 μg mL-1, including 15.7% with an MIC of 8 μg mL-1 and 2% with an MIC of 16 μg mL-1. The presence of the icaADBC operon, biofilm production and reduced susceptibility to vancomycin were associated with methicillin resistance. This study reveals a high level of methicillin resistance, biofilm formation and reduced susceptibility to vancomycin in subpopulations of S. epidermidis. These findings may explain the selection of multidrug-resistant isolates in hospital settings and the consequent failure of antimicrobial treatment.

The increase of methicillin-resistant Staphylococcus aureus (MRSA) and the presence of an unusual sequence type ST49 in slaughter pigs in Switzerland

Science.gov (United States)

2011-01-01

Background In years past, methicillin-resistant S. aureus (MRSA) has been frequently detected in pigs in Europe, North America and Asia. Recent, yet sporadic studies have revealed a low occurrence of MRSA in Switzerland. In 2009, a monitoring survey of the prevalence and genetic diversity of methicillin-resistant S. aureus (MRSA) in slaughter pigs in Switzerland was conducted using methods recommended by the EU guidelines, and using a sampling strategy evenly distributed throughout the year and representative of the Swiss slaughter pig population. Monitoring should determine if the overall prevalence of MRSA in the entire country is increasing over the years and if specific multi-resistant MRSA clones are spreading over the country. Results In 2009, the nasal cavities of eight out of 405 randomly selected pigs were positive for MRSA, representing a prevalence of 2.0% (95% CI 0.9-3.9). The following year, 23 out of 392 pigs were positive for MRSA [5.9% prevalence (95% CI 3.8-8.7)]. Three multilocus sequence types (ST), four spa types and two types of staphylococcal cassette chromosome mec (SCCmec) elements were detected. The most frequent genotypes were ST398 (MLST)-(spa)t034-V(SCCmec) (n = 18) and ST49-t208-V (n = 7), followed by ST398-t011-V (n = 4), ST398-t1451-V (n = 1), and ST1-t2279-IVc (n = 1). The isolates displayed resistance to ß-lactams [mecA, (31/31); blaZ, (19/31)]; tetracycline [tet(M), (31/31); tet(K), (30/31)] (n = 31); macrolides and lincosamides [erm(C) (4/31) or erm(A) (18/31)] (n = 22); tiamulin [vga(A)v (9/31) or unknown mechanism (18/31)] (n = 27); trimethoprim [dfr(G) (18/31); spectinomycin [ant(9)-Ia (19/31) or unknown mechanism (3/31)] (n = 22); streptomycin [str (19/31)]; sulphamethoxazole (7/31) and ciprofloxacin (n = 1) (mechanisms not determined). Conclusions This study is the first to describe the presence of MRSA ST49 in slaughter pigs, and to demonstrate a significant and nearly three-fold increase of MRSA prevalence in pigs within

The increase of methicillin-resistant Staphylococcus aureus (MRSA and the presence of an unusual sequence type ST49 in slaughter pigs in Switzerland

Directory of Open Access Journals (Sweden)

Büttner Sabina

2011-06-01

Full Text Available Abstract Background In years past, methicillin-resistant S. aureus (MRSA has been frequently detected in pigs in Europe, North America and Asia. Recent, yet sporadic studies have revealed a low occurrence of MRSA in Switzerland. In 2009, a monitoring survey of the prevalence and genetic diversity of methicillin-resistant S. aureus (MRSA in slaughter pigs in Switzerland was conducted using methods recommended by the EU guidelines, and using a sampling strategy evenly distributed throughout the year and representative of the Swiss slaughter pig population. Monitoring should determine if the overall prevalence of MRSA in the entire country is increasing over the years and if specific multi-resistant MRSA clones are spreading over the country. Results In 2009, the nasal cavities of eight out of 405 randomly selected pigs were positive for MRSA, representing a prevalence of 2.0% (95% CI 0.9-3.9. The following year, 23 out of 392 pigs were positive for MRSA [5.9% prevalence (95% CI 3.8-8.7]. Three multilocus sequence types (ST, four spa types and two types of staphylococcal cassette chromosome mec (SCCmec elements were detected. The most frequent genotypes were ST398 (MLST-(spat034-V(SCCmec (n = 18 and ST49-t208-V (n = 7, followed by ST398-t011-V (n = 4, ST398-t1451-V (n = 1, and ST1-t2279-IVc (n = 1. The isolates displayed resistance to ß-lactams [mecA, (31/31; blaZ, (19/31]; tetracycline [tet(M, (31/31; tet(K, (30/31] (n = 31; macrolides and lincosamides [erm(C (4/31 or erm(A (18/31] (n = 22; tiamulin [vga(Av (9/31 or unknown mechanism (18/31] (n = 27; trimethoprim [dfr(G (18/31; spectinomycin [ant(9-Ia (19/31 or unknown mechanism (3/31] (n = 22; streptomycin [str (19/31]; sulphamethoxazole (7/31 and ciprofloxacin (n = 1 (mechanisms not determined. Conclusions This study is the first to describe the presence of MRSA ST49 in slaughter pigs, and to demonstrate a significant and nearly three-fold increase of MRSA prevalence in pigs within two years

An Internet Study of User's Experiences of the Synthetic Cathinone 4-Methylethcathinone (4-MEC).

Science.gov (United States)

Van Hout, Marie Claire

2014-01-01

Abstract A synthetic cathinone called 4-methylethcathinone (4-MEC) emerged online in 2010, and was cyber-marketed to be a replacement for mephedrone. The study aimed to present user experiences of 4-MEC as reported on the Internet, with a focus on user profiles, sourcing and product characteristics, routes of administration, dosage, positive and undesirable effects, and comparisons to mephedrone. Twenty-three individual, anonymous trip reports of the sole use of 4-MEC, and 112 screenshots of general 4-MEC user discussion boards, were taken from a purposeful sample of public drug-related sites. A content textual analysis was conducted on extracted qualitative information and produced 41 categories compiled into five general themes: "Type of 4-MEC user"; "Sourcing, informed decision making, product characteristics, and quality assurance"; "Routes of administration, gauging of dosage, and consumption of other drugs"; "Time course effects and outcomes"; and "Comparisons with mephedrone." 4-MEC is sold as white beads, crystalline shards, or green balls. User motives centered on curiosity, pricing, and ease of web sourcing. Oral, nasal, injecting, eyeball, and rectal routes of administration were described. Testing for purity, "allergy testing," and gauging of dosage were common. Users described euphoric but short-lived effects, with little comedown. Continued research is vital to inform harm reduction.

Emergence of Community-Associated Methicillin-Resistant Staphylococcus aureus Associated with Pediatric Infection in Cambodia

Science.gov (United States)

Chheng, Kheng; Tarquinio, Sarah; Wuthiekanun, Vanaporn; Sin, Lina; Thaipadungpanit, Janjira; Amornchai, Premjit; Chanpheaktra, Ngoun; Tumapa, Sarinna; Putchhat, Hor; Day, Nicholas P. J.; Peacock, Sharon J.

2009-01-01

Background The incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection is rising in the developed world but appears to be rare in developing countries. One explanation for this difference is that resource poor countries lack the diagnostic microbiology facilities necessary to detect the presence of CA-MRSA carriage and infection. Methodology and Principal Findings We developed diagnostic microbiology capabilities at the Angkor Hospital for Children, Siem Reap, western Cambodia in January 2006 and in the same month identified a child with severe community-acquired impetigo caused by CA-MRSA. A study was undertaken to identify and describe additional cases presenting between January 2006 and December 2007. Bacterial isolates underwent molecular characterization using multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec) typing, and PCR for the presence of the genes encoding Panton-Valentine Leukocidin (PVL). Seventeen children were identified with CA-MRSA infection, of which 11 had skin and soft tissue infection and 6 had invasive disease. The majority of cases were unrelated in time or place. Molecular characterization identified two independent MRSA clones; fifteen isolates were sequence type (ST) 834, SCCmec type IV, PVL gene-negative, and two isolates were ST 121, SCCmec type V, PVL gene-positive. Conclusions This represents the first ever report of MRSA in Cambodia, spread of which would pose a significant threat to public health. The finding that cases were mostly unrelated in time or place suggests that these were sporadic infections in persons who were CA-MRSA carriers or contacts of carriers, rather than arising in the context of an outbreak. PMID:19675670

Emergence of community-associated methicillin-resistant Staphylococcus aureus associated with pediatric infection in Cambodia.

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Kheng Chheng

2009-08-01

Full Text Available The incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA infection is rising in the developed world but appears to be rare in developing countries. One explanation for this difference is that resource poor countries lack the diagnostic microbiology facilities necessary to detect the presence of CA-MRSA carriage and infection.We developed diagnostic microbiology capabilities at the Angkor Hospital for Children, Siem Reap, western Cambodia in January 2006 and in the same month identified a child with severe community-acquired impetigo caused by CA-MRSA. A study was undertaken to identify and describe additional cases presenting between January 2006 and December 2007. Bacterial isolates underwent molecular characterization using multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec typing, and PCR for the presence of the genes encoding Panton-Valentine Leukocidin (PVL. Seventeen children were identified with CA-MRSA infection, of which 11 had skin and soft tissue infection and 6 had invasive disease. The majority of cases were unrelated in time or place. Molecular characterization identified two independent MRSA clones; fifteen isolates were sequence type (ST 834, SCCmec type IV, PVL gene-negative, and two isolates were ST 121, SCCmec type V, PVL gene-positive.This represents the first ever report of MRSA in Cambodia, spread of which would pose a significant threat to public health. The finding that cases were mostly unrelated in time or place suggests that these were sporadic infections in persons who were CA-MRSA carriers or contacts of carriers, rather than arising in the context of an outbreak.

Methicillin-resistant Staphylococcus aureus in public transportation vehicles (buses): another piece to the epidemiologic puzzle.

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Lutz, Jonathan K; van Balen, Joany; Crawford, John Mac; Wilkins, John R; Lee, Jiyoung; Nava-Hoet, Rocio C; Hoet, Armando E

2014-12-01

Little is known about the occurrence and epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in public transportation in the United States. This research sought to determine the background prevalence and phenotypic and genotypic characteristics of MRSA strains circulating on buses from a large, metropolitan transportation agency. Electrostatic wipes were used to collect 237 surface samples from 40 buses randomly selected from July-October 2010. Six samples were collected from each bus immediately postservice and before any cleaning and disinfection. Positive isolates were analyzed for antibiotic resistance, staphylococcal cassette chromosome mec (SCCmec) type, and pulsed-field gel electrophoresis; and potential epidemiologic factors were examined. Of the buses, 68% (27/40) were contaminated with S aureus, and 63% (25/40) were contaminated with MRSA. Seats and seat rails were the surfaces most frequently contaminated, followed by the back door and stanchions. Most (62.9%) of the MRSA isolates were classified as community-associated MRSA clones (SCCmec type IV), and 22.9% were health care-associated MRSA clones (SCCmec type II). Of the MRSA strains, 65% (5/20) were multidrug resistant. MRSA was frequently isolated from commonly touched surfaces in buses serving both hospital and community routes. Phenotypic and genotypic analysis demonstrated that buses may be effective mixing vessels for MRSA strains of both community and health care-associated origin. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Impairments of mecA gene detection in bovine Staphylococcus spp.

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Dayanne Araújo de Melo

2014-09-01

Full Text Available Staphylococcus aureus antimicrobial resistance, especially to beta-lactams, favors treatment failures and its persistence in herd environment. This work aimed to develop a more specific primer for mecA gene detection based on the comparison of the conserved regions from distinct host origins and also investigated the presence of homologue mecA LGA251 in bovine strains. A total of 43 Staphylococcus spp. were included in this study, comprising 38 bovine S. aureus, two human and three equine coagulase-negative staphylococci (CNS. Phenotypical methicillin-resistance detection was performed through oxacillin agar-screening and cefoxitin disk-diffusion test. None isolate tested positive for mecA LGA251 gene. For mecA gene PCR, new primers were designed based on the sequences of human S. aureus (HE681097 and bovine S. sciuri (AY820253 mecA. The new primers based on the S. aureus mecA sequence amplified fragments of human and equine CNS and the ones based on S. sciuri mecA sequence only yielded fragments for S. aureus bovine strains. Multiples alignments of mecA gene sequences from bovine, human and equine revealed punctual but significant differences in bovine strains that can lead to the mecA gene detection impairment. The observed divergences of mecA gene sequences are not a matter of animal or human origin, it is a specificity of bovine samples.

Cambios a lo largo del tiempo en la distribución de los complejos de clones dominantes de Staphylococcus aureus resistente a la meticilina en Medellín, Colombia

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Ana M. Ocampo

2014-04-01

Full Text Available Introducción. Parte del éxito de Staphylococcus aureus resistente a la meticilina (SARM como patógeno se debe a la rápida diseminación de linajes pandémicos con perfiles variables de virulencia y sensibilidad antimicrobiana. En Colombia se han identificado clones asociados al hospital como el pediátrico (CC5-ST5-SCCmecIV, el brasilero (CC8-ST239-SCCmecIII y el chileno/cordobés (CC5-ST5-SCCmecI. Asimismo, se describió el USA300 (CC8-ST8-SCCmecIV, tradicionalmente asociado a la comunidad, causante de infecciones hospitalarias. Objetivo. Describir el comportamiento en el tiempo de los clones de SARM provenientes de un hospital universitario de Medellín en aislamientos recolectados con una década de diferencia. Materiales y métodos. Se analizaron 398 aislamientos de SARM, 67 recolectados en 1994 y 331 recolectados entre 2008 y 2010. La identificación y la sensibilidad a la meticilina se confirmaron mediante los genes nuc y mecA. La caracterización molecular incluyó la tipificación de spa, SCCmec, la electroforesis en gel de campo pulsado (Pulsed Field Gel Electrophoresis, PFGE, y la tipificación por secuenciación de locus múltiples (Multilocus Sequence Typing, MLST. Resultados. Al analizar los aislamientos de SARM de 1994 se encontró que pertenecían a un único linaje, el CC5-SCCmecIV, mientras que los aislamientos de 2008 a 2010 presentaron dos linajes dominantes: el CC8-SCCmecIVc, con cepas de los tipos spa t008 y t1610, estrechamente relacionadas con el clon USA 300, y el CC5-SCCmecI, con las de tipo spa t149, relacionadas con el clon chileno; no se detectaron cepas del linaje encontrado en 1994. Conclusiones. En este estudio se demuestra una dinámica en el tiempo de las cepas de S. aureus, y se señala la importancia de la vigilancia local y la difusión de los resultados, sobre todo en países como el nuestro, donde SARM es prevalente y la comprensión de su epidemiología es limitada.

Whole-genome comparison of meticillin-resistant Staphylococcus aureus CC22 SCCmecIV from people and their in-contact pets.

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Loeffler, Anette; McCarthy, Alex; Lloyd, David H; Musilová, Eva; Pfeiffer, Dirk U; Lindsay, Jodi A

2013-10-01

Meticillin-resistant Staphylococcus aureus (MRSA) infections remain important medical and veterinary challenges. The MRSA isolated from dogs and cats typically belong to dominant hospital-associated clones, in the UK mostly EMRSA-15 (CC22 SCCmecIV), suggesting original human-to-animal transmission. Nevertheless, little is known about host-specific genetic variation within the same S. aureus lineage. To identify host-specific variation amongst MRSA CC22 SCCmecIV by comparing isolates from pets with those from in-contact humans using whole-genome microarray. Six pairs of MRSA CC22 SCCmecIV from human carriers (owners and veterinary staff) and their respective infected in-contact pets were compared using a 62-strain whole-genome S. aureus microarray (SAM-62). The presence of putative host-specific genes was subsequently determined in a larger number of human (n = 47) and pet isolates (n = 93) by PCR screening. Variation in mobile genetic elements (MGEs) occurred frequently and appeared largely independent of host and in-contact pair. A plasmid (SAP078A) encoding heavy-metal resistance genes (arsR, arsA, cadA, cadC, mco and copB) was found in three of six human and none of six animal isolates. However, only two of four resistance genes were associated with human hosts (P = 0.015 for arsA and cadA). The variation found amongst MGEs highlights that genetic adaptation in MRSA continues. However, host-specific MGEs were not detected, which supports the hypothesis that pets may not be natural hosts of MRSA CC22 and emphasizes that rigorous hygiene measures are critical to prevent contamination and infection of dogs and cats. The host specificity of individual heavy-metal resistance genes warrants further investigation into different selection pressures in humans and animals. © 2013 ESVD and ACVD.

Neumonía necrosante por Staphylococcus aureus extrahospitalario resistente a la meticilina:reporte de dos casos en Colombia

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Ana María Perilla

2009-12-01

Ambos desarrollaron falla renal aguda, por lo que fueron manejados con linezolide, con adecuada respuesta clínica. Con la caracterización molecular de los aislamientos se confirmó la presencia del gen mecA que porta el casete SCCmec tipo IV y la producción de la toxina leucocidina Panton-Valentine.

Coagulase-negative staphylococci causing blood stream infection at an Indian tertiary care hospital: Prevalence, antimicrobial resistance and molecular characterisation

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S Singh

2016-01-01

Full Text Available Introduction: Recent years have seen a rise of coagulase-negative staphylococci (CoNS from common contaminants to agents of nosocomial blood stream infections (BSI's. Molecular typing and establishing a correlation with antibiotic resistance is essential particularly in countries like India where genotyping studies for drug-resistant CoNS are sparse. Methods: A prospective study was done over 18 months, wherein 42,693 blood samples were received, and 59 patients with BSI due to CoNS were evaluated. The isolates recovered were identified by a biochemical test panel and matrix-assisted laser desorption ionization – time of flight mass spectrometry followed by antimicrobial susceptibility testing by Kirby–Baur disc diffusion method and E-test strips. Staphylococcal chromosomal cassette mec (SCCmec element was characterised by multiplex polymerase chain reaction for all methicillin-resistant (MR isolates. Results: The majority of CoNS isolated were constituted by Staphylococcus haemolyticus (47.5% followed by Staphylococcus epidermidis (33.9%, Staphylococcus hominis (11.86%, Staphylococcus cohnii (5.08% and Staphylococcus warneri (1.69%. Among all isolates 57.6% were MR with statistically significant higher resistance versus methicillin sensitive-CoNS. This difference was significant for erythromycin (76% vs. 44%, P = 0.011, rifampicin (50% vs. 12%,P= 0.002 and amikacin (26.5% vs. 4%, P = 0.023, ciprofloxacin (64.7% vs. 20%, P = 0.001 and cotrimoxazole (55.9% vs. 20%, P = 0.006. SCCmec type I was predominant (61.8%, P = 0.028 and exhibited multidrug resistance (76.2%. Coexistence of SCCmec type I and III was seen in 8.82% MR isolates. Conclusion: CoNS exhibit high antimicrobial resistance thereby limiting treatment options. The presence of new variants of SCCmec type in hospital-acquired CoNS may predict the antibiotic resistance pattern. This is the first evaluation of the molecular epidemiology of CoNS causing BSI from India and can serve as a

Coagulase-negative staphylococci causing blood stream infection at an Indian tertiary care hospital: Prevalence, antimicrobial resistance and molecular characterisation.

Science.gov (United States)

Singh, S; Dhawan, B; Kapil, A; Kabra, S K; Suri, A; Sreenivas, V; Das, B K

2016-01-01

Recent years have seen a rise of coagulase-negative staphylococci (CoNS) from common contaminants to agents of nosocomial blood stream infections (BSI's). Molecular typing and establishing a correlation with antibiotic resistance is essential particularly in countries like India where genotyping studies for drug-resistant CoNS are sparse. A prospective study was done over 18 months, wherein 42,693 blood samples were received, and 59 patients with BSI due to CoNS were evaluated. The isolates recovered were identified by a biochemical test panel and matrix-assisted laser desorption ionization - time of flight mass spectrometry followed by antimicrobial susceptibility testing by Kirby-Baur disc diffusion method and E-test strips. Staphylococcal chromosomal cassette mec (SCCmec) element was characterised by multiplex polymerase chain reaction for all methicillin-resistant (MR) isolates. The majority of CoNS isolated were constituted by Staphylococcus haemolyticus (47.5%) followed by Staphylococcus epidermidis (33.9%), Staphylococcus hominis (11.86%), Staphylococcus cohnii (5.08%) and Staphylococcus warneri (1.69%). Among all isolates 57.6% were MR with statistically significant higher resistance versus methicillin sensitive-CoNS. This difference was significant for erythromycin (76% vs. 44%, P = 0.011), rifampicin (50% vs. 12%,P= 0.002) and amikacin (26.5% vs. 4%, P = 0.023), ciprofloxacin (64.7% vs. 20%, P = 0.001) and cotrimoxazole (55.9% vs. 20%, P = 0.006). SCCmec type I was predominant (61.8%, P = 0.028) and exhibited multidrug resistance (76.2%). Coexistence of SCCmec type I and III was seen in 8.82% MR isolates. CoNS exhibit high antimicrobial resistance thereby limiting treatment options. The presence of new variants of SCCmec type in hospital-acquired CoNS may predict the antibiotic resistance pattern. This is the first evaluation of the molecular epidemiology of CoNS causing BSI from India and can serve as a guide in the formulation of hospital infection

A Livestock-Associated, Multidrug-Resistant, Methicillin-Resistant Staphylococcus aureus Clonal Complex 97 Lineage Spreading in Dairy Cattle and Pigs in Italy.

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Feltrin, Fabiola; Alba, Patricia; Kraushaar, Britta; Ianzano, Angela; Argudín, María Angeles; Di Matteo, Paola; Porrero, María Concepción; Aarestrup, Frank M; Butaye, Patrick; Franco, Alessia; Battisti, Antonio

2016-02-01

Pandemic methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 97 (CC97) lineages originated from livestock-to-human host jumps. In recent years, CC97 has become one of the major MRSA lineages detected in Italian farmed animals. The aim of this study was to characterize and analyze differences in MRSA and methicillin-susceptible S. aureus (MSSA) mainly of swine and bovine origins. Forty-seven CC97 isolates, 35 MRSA isolates, and 6 MSSA isolates from different Italian pig and cattle holdings; 5 pig MRSA isolates from Germany; and 1 human MSSA isolate from Spain were characterized by macrorestriction pulsed-field gel electrophoresis (PFGE) analysis, multilocus sequence typing (MLST), spa typing, staphylococcal cassette chromosome mec (SCCmec) typing, and antimicrobial resistance pattern analysis. Virulence and resistance genes were investigated by PCR and microarray analysis. Most of the isolates were of SCCmec type V (SCCmec V), except for two German MRSA isolates (SCCmec III). Five main clusters were identified by PFGE, with the German isolates (clusters I and II) showing 60.5% similarity with the Italian isolates, most of which (68.1%) grouped into cluster V. All CC97 isolates were Panton-Valentine leukocidin (PVL) negative, and a few (n = 7) tested positive for sak or scn. All MRSA isolates were multidrug resistant (MDR), and the main features were erm(B)- or erm(C)-mediated (n = 18) macrolide-lincosamide-streptogramin B resistance, vga(A)-mediated (n = 37) pleuromutilin resistance, fluoroquinolone resistance (n = 33), tet(K) in 32/37 tet(M)-positive isolates, and blaZ in almost all MRSA isolates. Few host-associated differences were detected among CC97 MRSA isolates: their extensive MDR nature in both pigs and dairy cattle may be a consequence of a spillback from pigs of a MRSA lineage that originated in cattle as MSSA and needs further investigation. Measures should be implemented at the farm level to prevent spillover to humans in intensive farming

Meticillin-resistant Staphylococcus aureus (MRSA)

DEFF Research Database (Denmark)

Stefani, Stefania; Chung, Doo Ryeon; Lindsay, Jodi A

2012-01-01

decisions with regard to harmonisation of typing methods. A stratified, three-level organisation of testing laboratories was proposed: local; regional; and national. The functions of, and testing methodology used by, each laboratory were defined. The group consensus was to recommend spa and staphylococcal......This article reviews recent findings on the global epidemiology of healthcare-acquired/associated (HA), community-acquired/associated (CA) and livestock-associated (LA) meticillin-resistant Staphylococcus aureus (MRSA) and aims to reach a consensus regarding the harmonisation of typing methods...... cassette chromosome mec (SCCmec) typing as the preferred methods. Both are informative in defining particular strain characteristics and utilise standardised nomenclatures, making them applicable globally. Effective communication between each of the different levels and between national centres was viewed...

Methicillin-resistant Staphylococcus aureus containing mecC in Swedish dairy cows

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Unnerstad Helle Ericsson

2013-01-01

Full Text Available Abstract Background Hitherto, methicillin-resistant Staphylococcus aureus (MRSA has not been detected in Swedish cattle. However, due to the report of mecC, a novel homologue to the mecA gene, there was reason to re-evaluate susceptibility results from strain collections of Staphylococcus aureus and test suspected isolates for the presence of mecC. Findings Bovine isolates of S. aureus with elevated minimum inhibitory concentrations of beta-lactams were retrospectively tested for presence of mecC. In four of the isolates mecC was detected. Conclusion In Sweden, this is the first finding of MRSA in cattle and the first detection of MRSA harbouring mecC of domestic animal origin. MRSA in animal populations has implications as a potential reservoir with risk for spread to humans. Occurrence of MRSA among Swedish cattle appears still very limited.

Staphylococcus aureus resistente a meticilina causante de infecciones comunitarias y de infecciones asociadas a la atención en salud en pacientes pediátricos del Hospital Universitario de Santander

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Mayra Alejandra Machuca

2014-04-01

Full Text Available Introducción. Staphylococcus aureus resistente a la meticilina (SARM es un agente frecuente de infección en la población pediátrica. Aunque inicialmente las cepas de SARM estaban restringidas a los hospitales, se han reportado a nivel mundial brotes de infección por SARM en individuos sin factores de riesgo y, actualmente, SARM es una causa frecuente de infecciones hospitalarias y comunitarias. Objetivo. Describir la relación entre las características moleculares de aislamientos de SARM (casete cromosómico estafilocócico mec SCCmec y leucocidina Panton-Valentine y el origen de la infección y su presentación clínica en pacientes pediátricos del Hospital Universitario de Santander en Bucaramanga, Colombia. Materiales y métodos. Se incluyeron 43 aislamientos de SARM obtenidos de niños hospitalizados. La clasificación del SCCmec (I-V y la subclasificación del SCCmec-IV se realizaron en todos los aislamientos. Además, los genes de la leucocidina Panton-Valentine se detectaron mediante amplificación por PCR. Las características moleculares fueron asociadas con las características clínicas de cada paciente. Resultados. Entre los 43 SARM tipificados, el SCCmec-IVc fue el más frecuente con 77 %, seguido por el SCCmec-I con 16 % y el SCCmec-IVa con 2 %. Tres aislamientos no pudieron ser tipificados. Los genes de la leucocidina Panton Valentine se detectaron en 88 % de los SARM en aislamientos portadores del SCCmec-IVc/IVa y el SCCmec-I. Los SARM SCCmec-IV positivos para la leucocidina Panton-Valentine se asociaron con infecciones adquiridas en la comunidad (47 % y en el hospital (53 % con compromiso de piel y tejidos blandos, y en los casos más graves, con compromiso osteoarticular. Conclusiones. Estos resultados sugieren la presencia de cepas SARM-CO (SCCmec-IV positiva para PVL causantes de infecciones adquiridas en la comunidad y en el medio hospitalario en pacientes pediátricos en Colombia.

Mecánica de los suelos

OpenAIRE

Duque Escobar, Gonzalo; Escobar Potes, Carlos Enrique

2002-01-01

Mecánica de los suelos: texto para la asignatura Mecánica de Suelos I del programa de Ingeniería Civil de la Universidad Nacional de Colombia sede Manizales, cuyo contenido desarrollado en 15 capítulos, es: Origen, formación y constitución del Suelo. Las arcillas. Relaciones de volumen y peso para Suelos. Estructura del suelo y granulometría. Plasticidad de los Suelos. Clasificación e identificación de los Suelos. Capilaridad. Propiedades hidráulicas de los suelos. Redes d...

Interspecies spread of Staphylococcus aureus clones among companion animals and human close contacts in a veterinary teaching hospital. A cross-sectional study in Greece.

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Drougka, Eleanna; Foka, Antigoni; Koutinas, Christos K; Jelastopulu, Eleni; Giormezis, Nikolaos; Farmaki, Ourania; Sarrou, Styliani; Anastassiou, Evangelos D; Petinaki, Efthimia; Spiliopoulou, Iris

2016-04-01

Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) prevalence among companion animals and veterinary personnel (VP) was investigated. Strains' molecular characteristics were evaluated in order to assess S. aureus transmission. Specimens (224) from colonized and infected sites of 102 animals (92 dogs, 10 cats) and 18 VP were collected during 2012 and 2013. Antibiotic susceptibility was performed by the disk diffusion method and Etest. mecA, mecC, tst (toxic shock syndrome toxin) and lukF/lukS-PV (Panton-Valentine leukocidin, PVL) genes were investigated by PCR. Genotypes were identified by Multi Locus Sequence Typing (MLST), Staphylococcal Cassette Chromosome mec (SCCmec), accessory gene regulator group (agr), spa and Pulsed Field Gel Electrophoresis (PFGE). S. aureus prevalence among pets and VP was 36.3% (37/102) and 38.9% (7/18), respectively. Younger companion animals, those living in rural areas, having a disease upon admission or Coagulase-negative staphylococci co-carriage showed significantly higher prevalence of S. aureus isolation (panimals and VP. Companion animals harbor PVL-positive clones constituting a possible source for transmission to humans. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecular characterization of nasal methicillin resistant Staphylococcus aureus isolates from workers of an automaker company in southeast Iran.

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Sobhanipoor, Mohammad Hossein; Ahmadrajabi, Roya; Karmostaji, Afsaneh; Saffari, Fereshteh

2017-10-01

Colonization of methicillin resistant Staphylococccus aureus (MRSA) can occur more commonly in healthy people who live in close together or are in close physical contact with each other. Having knowledge about the molecular characteristics of these strains provides considerable discernment into the epidemiology of this important microorganism. A total of 806 nasal swabs were collected from healthy workers of an automaker company in the southeast of Iran and were analyzed to detect MRSA isolates. Multilocus sequence typing (MLST), spa typing, and detection of staphylococcal cassette chromosome mec (SCCmec) were performed. The presence of genes encoding Panton-Valentine Leukocidin (PVL) and Arginine Catabolic Mobile Element (ACME) were also investigated. Carriage rate of S. aureus was 20%. Among 10 identified MRSA, no acme was found while high prevalence of pvl (60%) was of great concern. Seven different spa types including five new ones were identified. The most frequent sequence type was the novel one; ST 3373 (n = 3), followed by each of ST22, ST88, ST859 (n = 2) and ST1955 (n = 1). MRSA isolates were clustered into two main clonal complexes; CC22 (n = 6) and CC88 (n = 4). Low genetic diversity with the dominance of CC22, SCCmecIV was found. Distribution of previously found hospital-associated MRSA was demonstrated among our isolates. © 2017 APMIS. Published by John Wiley & Sons Ltd.

Relatividad galileana y ondas mecánicas

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Londoño Vega, Mario Felipe

1991-01-01

Las leyes de la mecánica son las mismas para todos los observadores inerciales, observadores que se mueven con velocidad constante unos respecto a otros. Así lo asevera el principio de la relatividad galileana ( o Newtoniana). Los diversos observadores correlacionan su observación mediante las transformaciones galileana y así, cuando en la expresión de una ley de la mecánica efectuamos una de tales transformaciones, la ley no cambia, su forma permanece inalterada: decimos que es invariante b...

Low prevalence of methicillin-resistant Staphylococcus aureus nasal carriage in urban and rural community settings in Bolivia and Peru.

Science.gov (United States)

Bartoloni, Alessandro; Pallecchi, Lucia; Fernandez, Connie; Mantella, Antonia; Riccobono, Eleonora; Magnelli, Donata; Mannini, Dario; Strohmeyer, Marianne; Bartalesi, Filippo; Segundo, Higinio; Monasterio, Joaquin; Rodriguez, Hugo; Cabezas, César; Gotuzzo, Eduardo; Rossolini, Gian Maria

2013-05-01

To investigate the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage in rural and urban community settings of Bolivia and Peru. MRSA nasal carriage was investigated in 585 individuals living in rural and urban areas of Bolivia and Peru (one urban area, one small rural village, and two native communities, one of which was highly isolated). MRSA isolates were subjected to molecular analysis for the detection of virulence genes, characterization of the staphylococcal cassette chromosome mec (SCCmec), and genotyping (multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE)). An overall very low prevalence of MRSA nasal carriage was observed (0.5%), with MRSA carriers being detected only in a small rural village of the Bolivian Chaco. The three MRSA isolates showed the characteristics of community-associated MRSA (being susceptible to all non-beta-lactam antibiotics and harboring the SCCmec type IV), were clonally related, and belonged to ST1649. This study provides an insight into the epidemiology of MRSA in community settings of Bolivia and Peru. Reliable, time-saving, and low-cost methods should be implemented to encourage continued surveillance of MRSA dissemination in resource-limited countries. Copyright © 2012 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Ddc2 mediates Mec1 activation through a Ddc1- or Dpb11-independent mechanism.

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Amitava Bandhu

2014-02-01

Full Text Available The protein kinase Mec1 (ATR ortholog and its partner Ddc2 (ATRIP ortholog play a key role in DNA damage checkpoint responses in budding yeast. Previous studies have established the model in which Ddc1, a subunit of the checkpoint clamp, and Dpb11, related to TopBP1, activate Mec1 directly and control DNA damage checkpoint responses at G1 and G2/M. In this study, we show that Ddc2 contributes to Mec1 activation through a Ddc1- or Dpb11-independent mechanism. The catalytic activity of Mec1 increases after DNA damage in a Ddc2-dependent manner. In contrast, Mec1 activation occurs even in the absence of Ddc1 and Dpb11 function at G2/M. Ddc2 recruits Mec1 to sites of DNA damage. To dissect the role of Ddc2 in Mec1 activation, we isolated and characterized a separation-of-function mutation in DDC2, called ddc2-S4. The ddc2-S4 mutation does not affect Mec1 recruitment but diminishes Mec1 activation. Mec1 phosphorylates histone H2A in response to DNA damage. The ddc2-S4 mutation decreases phosphorylation of histone H2A more significantly than the absence of Ddc1 and Dpb11 function does. Our results suggest that Ddc2 plays a critical role in Mec1 activation as well as Mec1 localization at sites of DNA damage.

High prevalence of EMRSA-15 in Portuguese public buses: a worrisome finding.

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Roméo Rocha Simões

Full Text Available BACKGROUND: The nosocomial prevalence of methicillin resistant Staphylococcus aureus (MRSA in Portugal remains one of the highest in Europe and is currently around 50%. Transmission of S. aureus, including MRSA, occurs principally by direct human-to-human skin contact. However, S. aureus can survive for long periods on inanimate objects, which may represent an important reservoir for dissemination as well. METHODOLOGY/PRINCIPAL FINDINGS: Between May 2009 and February 2010, handrails of 85 public urban buses circulating in Oporto, Portugal, were screened for the occurrence of MRSA. Twenty-two (26% buses showed MRSA contamination. The molecular characterization of a total of 55 MRSA, by pulsed-field gel electrophoresis (PFGE, staphylococcal cassette chromosome (SCC mec typing, spa typing, and multilocus sequence typing (MLST, clustered the isolates into three clonal types. However, the overwhelming majority (n = 50; 91% of the isolates belonged to a single clone (PFGE A, spa types t747, t032, t025 or t020, ST22, SCCmec type IVh that exhibits the characteristics of the pandemic EMRSA-15, currently the major lineage circulating in Portuguese hospitals, namely in the Oporto region. Two additional clones were found but in much lower numbers: (i PFGE B, ST5, spa type t002, SCCmec IVa (n = 3, and (ii PFGE C, spa type t008, ST8, SCCmec IVa (n = 2. None of the 55 isolates was PVL positive. CONCLUSIONS/SIGNIFICANCE: Public buses in Oporto seem to be an important reservoir of MRSA of nosocomial origin, providing evidence that the major hospital-associated MRSA clone in Portugal is escaping from the primary ecological niche of hospitals to the community environment. Infection control measures are urgently warranted to limit the spread of EMRSA-15 to the general population and future studies are required to assess the eventual increase of MRSA in the Portuguese community, which so far remains low.

Methicillin-resistant Staphylococcus aureus isolates from surfaces and personnel at a hospital laundry facility.

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Michael, K E; No, D; Roberts, M C

2016-09-01

Examine a clinical laundry facility for the presence of methicillin-resistant Staphylococcus aureus (MRSA) on environmental surfaces and among personnel. Nasal and face samples along with surface samples were collected four times in 2015. MRSA isolates were confirmed using standardized biochemical assays and molecular characterization. MRSA was identified in 33/120 (28%) samples from the dirty and 3/120 (3%) samples from the clean environmental areas. MRSA isolates included: (dirty) ST5 SCCmec type II, ST8 SCCmec type IV, ST231 SCCmec type II, ST239 SCCmec type III, ST239 SCCmec type IV, ST256 SCCmec type IV and (clean) ST5 SCCmec type II and ST8 SCCmec type IV. Five different employees were MRSA positive, 4/8 (50%) from the dirty: and 1/15 (6·7%) from the clean, but there was a 10-fold higher MRSA carriage 6/22 (27%) dirty vs 1/38 (2·6%) clean when all 50 human samples were combined. MRSA prevalence was significantly higher (28 vs 3%) in dirty vs clean areas within the laundry facility suggesting a greater risk for personnel on the dirty side. This is the first report of isolation and characterization of MRSA from surfaces and personnel from a clinical laundry facility. © 2016 The Society for Applied Microbiology.

MECs: "Building Blocks" for Creating Biological and Chemical Instruments.

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Douglas A Hill

Full Text Available The development of new biological and chemical instruments for research and diagnostic applications is often slowed by the cost, specialization, and custom nature of these instruments. New instruments are built from components that are drawn from a host of different disciplines and not designed to integrate together, and once built, an instrument typically performs a limited number of tasks and cannot be easily adapted for new applications. Consequently, the process of inventing new instruments is very inefficient, especially for researchers or clinicians in resource-limited settings. To improve this situation, we propose that a family of standardized multidisciplinary components is needed, a set of "building blocks" that perform a wide array of different tasks and are designed to integrate together. Using these components, scientists, engineers, and clinicians would be able to build custom instruments for their own unique needs quickly and easily. In this work we present the foundation of this set of components, a system we call Multifluidic Evolutionary Components (MECs. "Multifluidic" conveys the wide range of fluid volumes MECs operate upon (from nanoliters to milliliters and beyond; "multi" also reflects the multiple disciplines supported by the system (not only fluidics but also electronics, optics, and mechanics. "Evolutionary" refers to the design principles that enable the library of MEC parts to easily grow and adapt to new applications. Each MEC "building block" performs a fundamental function that is commonly found in biological or chemical instruments, functions like valving, pumping, mixing, controlling, and sensing. Each MEC also has a unique symbol linked to a physical definition, which enables instruments to be designed rapidly and efficiently using schematics. As a proof-of-concept, we use MECs to build a variety of instruments, including a fluidic routing and mixing system capable of manipulating fluid volumes over five orders

Complete substitution of the Brazilian endemic clone by other methicillin-resistant Staphylococcus aureus lineages in two public hospitals in Rio de Janeiro, Brazil.

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Chamon, Raiane Cardoso; Ribeiro, Sthefanie da Silva; da Costa, Thaina Miranda; Nouér, Simone Aranha; Dos Santos, Katia Regina Netto

Staphylococcus aureus is an important cause of bloodstream infections. Therefore, the main purpose of this work was to characterize a collection of 139 S. aureus isolates from bloodstream infections in two public hospitals in relation to their antimicrobial susceptibility profile, staphylococcal cassette chromosome mec types, and clonal relationship. Methicillin resistance and resistance to other 12 agents were accessed by the disk diffusion test. Minimum inhibitory concentration to mupirocin was also determined. The SCCmec types were accessed by multiplex PCR, and the clonal relationship was determined by pulsed field gel electrophoresis method and restriction modification system characterization. Besides, multilocus sequence typing was performed for representative methicillin-resistant S. aureus isolates. The military hospital showed a dissemination of the New York/Japan (USA100/ST5/CC5/SCCmecII) lineage associated to multidrug resistance, including mupirocin resistance, and the teaching hospital presented polyclonal and non-multidrug resistant MRSA isolates. Complete substitution of the Brazilian endemic clone by other lineages was found in both hospitals. These findings can highlight differences in policy control and prevention of infections used in the hospitals and a change in the epidemiological profile of MRSA in Brazilian hospitals, with the replacement of BEC, a previously well-established clone, by other lineages. Copyright © 2016 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. All rights reserved.

Changing epidemiology of methicillin-resistant Staphylococcus aureus in Iceland from 2000 to 2008: a challenge to current guidelines

DEFF Research Database (Denmark)

Holzknecht, B.J.; Hardardottir, H.; Haraldsson, Gustav Helgi

2010-01-01

, and screening for the Panton-Valentine leukocidin (PVL) gene. Two hundred twenty-six infected (60%) or colonized (40%) individuals were detected (annual incidence 2.5 to 16/100,000). From 2000 to 2003, two health care-associated outbreaks dominated (spa types t037 and t2802), which were successfully controlled...... with extensive infection control measures. After 2004, an increasing number of community-associated (CA) cases without relation to the health care system occurred. A great variety of clones (40 PFGE types and 49 spa types) were found, reflecting an influx of MRSA from abroad. The USA300 and Southwest Pacific...... and microbiological data of all MRSA patients from the years 2000 to 2008 were collected prospectively. Isolates were characterized by pulsed-field gel electrophoresis (PFGE), sequencing of the repeat region of the Staphylococcus protein A gene (spa typing), staphylococcal cassette chromosome mec (SCCmec) typing...

A Livestock-Associated, Multidrug-Resistant, Methicillin-Resistant Staphylococcus aureus Clonal Complex 97 Lineage Spreading in Dairy Cattle and Pigs in Italy

DEFF Research Database (Denmark)

Feltrin, Fabiola; Alba, Patricia; Kraushaar, Britta

2016-01-01

by macrorestriction pulsed-field gel electrophoresis (PFGE) analysis, multilocus sequence typing (MLST), spa typing, staphylococcal cassette chromosome mec (SCCmec) typing, and antimicrobial resistance pattern analysis. Virulence and resistance genes were investigated by PCR and microarray analysis. Most...... resistance, fluoroquinolone resistance (n = 33), tet(K) in 32/37 tet(M)-positive isolates, and blaZ in almost all MRSA isolates. Few host-associated differences were detected among CC97 MRSA isolates: their extensive MDR nature in both pigs and dairy cattle may be a consequence of a spillback from pigs......Pandemic methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 97 (CC97) lineages originated from livestock-to-human host jumps. In recent years, CC97 has become one of the major MRSA lineages detected in Italian farmed animals. The aim of this study was to characterize and analyze...

Molecular Characterization of Methicillin-Resistant Staphylococcus aureus from Outpatients in Northern Japan: Increasing Tendency of ST5/ST764 MRSA-IIa with Arginine Catabolic Mobile Element.

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Aung, Meiji Soe; Kawaguchiya, Mitsuyo; Urushibara, Noriko; Sumi, Ayako; Ito, Masahiko; Kudo, Kenji; Morimoto, Shigeo; Hosoya, Shino; Kobayashi, Nobumichi

2017-07-01

Arginine catabolic mobile element (ACME) is a genomic island of staphylococcus and is considered to confer enhanced ability to survive and growth on host bacterial cells. ACME has been typically identified in Panton-Valentine Leukocidin (PVL)-positive ST8 methicillin-resistant Staphylococcus aureus (MRSA) with SCCmec type IVa (USA300 clone), and it is also found in other lineages at low frequency. Prevalence and molecular characteristics of PVL + and/or ACME + MRSA were investigated for 624 clinical isolates collected from outpatients in northern Japan from 2013 to 2014. Both PVL genes and ACME type I were detected in nine isolates (1.4%), which were ST8-MRSA-SCCmec IVa/spa type t008/agr-I; whereas solely PVL genes were positive in two isolates, ST30-MRSA-SCCmec IV and ST59-MRSA-SCCmec V. ACME type II' (previously referred to as ACME ΔII) was detected in 36 isolates (5.8%) with SCCmec II and V (32 and 4 isolates, respectively), exhibiting an increased rate within SCCmec II-MRSA (7.1%) compared with our previous studies (0.86-4.5%, 2008-2011). ACME II'-positive MRSA strains were classified into ST5-SCCmec IIa/V or ST764-SCCmec IIa belonging to five different spa types, with t002 being dominant. They harbored mostly enterotoxin gene clusters (seg-sei-sem-sen-seo-seu) and some more enterotoxin genes (seb1, seb2, sec3, sel, sep), showing resistance to more antimicrobials than ST8-MRSA-SCCmec IVa. ACME-SCCmec composite island (CI) of the 36 ACME II'-positive MRSA was classified into five types (ii)-(vi), among which type (ii) (orfX-ΨSCC ΔJ1 SCCmec I -ACME II'-SCCmec II) was dominant and subdivided into the A3 variant and the less common A2 variant. CI types (v) and (vi) were considered novel genetic organizations having speG (acetyltransferase genes for polyamines) in inserted SCC4610/SCC266-like genetic elements. The present study revealed increased prevalence and genetic diversity of the ST5/ST764-MRSA-SCCmec II with ACME II' in northern Japan.

Mecánica de medios continuos para ingenieros

OpenAIRE

Oliver Olivella, Xavier; Agelet de Saracibar Bosch, Carlos

2002-01-01

Mecánica de medios continuos para ingenieros pretende ser una herramienta para la formación de los ingenieros en la mecánica de medios continuos, que mantiene un equilibrio adecuado entre la rigurosidad de su planteamiento y la claridad de los principios físicos tratados. El contenido del texto está claramente dividido en dos partes, que se presentan secuencialmente. En la primera (capítulos 1 a 5), se introducen los aspectos fundamentales y descriptivos comunes a todos los medios continu...

Mecánica de suelos : problemas resueltos

OpenAIRE

Olivella Pastallé, Sebastià

2001-01-01

Esta publicación contiene una colección de problemas resueltos de mecánica de suelos que ha sido preparada para los estudios de ingeniería técnica de obras públicas que se imparten en la UPC. Se trata de una titulación de primer ciclo, por lo que el enfoque que se da a los problemas se centra en aspectos de concepto y no requiere la realización de desarrollos matemáticos. Incluye problemas relativos a propiedades básicas de los suelos, aspectos básicos de la mecánica de medios porosos indefor...

Long-term molecular epidemiology of Staphylococcus epidermidis blood culture isolates from patients with hematological malignancies.

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Erik Ahlstrand

Full Text Available Staphylococcus epidermidis is an important cause of bloodstream infections in patients with hematological malignancies. Knowledge of the long-term epidemiology of these infections is limited. We surveyed all S. epidermidis blood culture isolates from patients treated for hematological malignancies at the University Hospital of Örebro, Sweden from 1980 to 2009. A total of 373 S. epidermidis isolates were identified and multilocus sequence typing, staphylococcal chromosome cassette mec (SCCmec typing and standard antibiotic susceptibility testing were employed to characterize these isolates. The majority of the isolates 361/373 (97% belonged to clonal complex 2, and the 373 isolates were divided into 45 sequence types (STs; Simpson's Diversity Index was 0.56. The most prevalent STs were ST2 (243/373, 65% and ST215 (28/373, 8%. Ninety three percent (226/243 of the ST2 isolates displayed either SCCmec type III or IV. ST2 and 215 were isolated during the entire study period, and together these STs caused temporal peaks in the number of positive blood cultures of S. epidermidis. Methicillin resistance was detected in 213/273 (78% of all isolates. In the two predominating STs, ST2 and ST215, methicillin resistance was detected in 256/271 isolates (95%, compared with 34/100 (34% in other STs (p<0.001. In conclusion, in this long-term study of patients with hematological malignancies, we demonstrate a predominance of methicillin-resistant ST2 among S. epidermidis blood culture isolates.

Analysis about modeling MEC7000 excitation system of nuclear power unit

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Liu, Guangshi; Sun, Zhiyuan; Dou, Qian; Liu, Mosi; Zhang, Yihui; Wang, Xiaoming

2018-02-01

Aiming at the importance of accurate modeling excitation system in stability calculation of nuclear power plant inland and lack of research in modeling MEC7000 excitation system,this paper summarize a general method to modeling and simulate MEC7000 excitation system. Among this method also solve the key issues of computing method of IO interface parameter and the conversion process of excitation system measured model to BPA simulation model. At last complete the simulation modeling of MEC7000 excitation system first time in domestic. By used No-load small disturbance check, demonstrates that the proposed model and algorithm is corrective and efficient.

Molecular characterization of methicillin resistant Staphylococcus aureus isolated from hospitals environments and patients in Northern Palestine

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Ghaleb Adwan

2015-09-01

Full Text Available BACKGROUND: Staphylococcus aureus (S. aureus is considered one of the most common pathogen to humans. Infections caused by this mocroorganism can be acquired through both hospital and community settings. This study was carried out to investigate molecular characterization of MRSA strains isolated from the patients and their environment in two hospitals (Rafidia hospital and Thabet hospital inNorthern Palestine, and to determine the clonal identity between these strains and their possible contribution to nosocomial infections.METHODS: Two hundred sixty five swabbed samples were collected from these hospitals, S. aureus was isolated,  antibiotic resistant genes were Panton–Valentin leukocidin (PVL gene were detected and SCCmec and spA were typed by PCR and/or sequencing.RESULTS: The prevalence of MRSA among S. aureus isolates was 29% and 8.2% in Rafidia hospital and Thabet hospital, respectively. All strains resistant to oxacilllin disk were carried mecA gene. Majority of strains (84.6% carried SCCmec type II (n = 11, type IVa and non-typeable were also detected. In addition, PVL was detected in 2 (14.3% clinical strains. ERIC PCR patterns revealed that 2 strains recovered from patient bed and nasal swab isolated from Thabet Hospital were nontypeable, spA typing showed that they belonged to type t386 and have identical DNA sequences. Other 2 clinical isolates were spa typed, one belonged to clone t044, while the other is new clone not exist in database.CONCLUSIONS: Results may give evidence that environmental contamination possibly contributing to nosocomial infections.

Cytoplasmic localization of Hug1p, a negative regulator of the MEC1 pathway, coincides with the compartmentalization of Rnr2p–Rnr4p

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Ainsworth, William B. [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States); Hughes, Bridget Todd; Au, Wei Chun; Sakelaris, Sally [Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Kerscher, Oliver [Biology Department, The College of William and Mary, Williamsburg, VA 23185 (United States); Benton, Michael G., E-mail: benton@lsu.edu [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States); Basrai, Munira A., E-mail: basraim@mail.nih.gov [Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States)

2013-10-04

Highlights: •Hug1p overexpression sensitizes wild-type cells to DNA damage and hydroxyurea (HU). •Expression of Hug1p in response to HU treatment is delayed relative to Rnr3p. •MEC1 pathway genes are required for cytoplasmic localization of Hug1p. •Hug1p subcellular compartmentalization to the cytoplasm coincides with Rnr2p–Rnr4p. -- Abstract: The evolutionarily conserved MEC1 checkpoint pathway mediates cell cycle arrest and induction of genes including the RNR (Ribonucleotide reductase) genes and HUG1 (Hydroxyurea, ultraviolet, and gamma radiation) in response to DNA damage and replication arrest. Rnr complex activity is in part controlled by cytoplasmic localization of the Rnr2p–Rnr4p subunits and inactivation of negative regulators Sml1p and Dif1p upon DNA damage and hydroxyurea (HU) treatment. We previously showed that a deletion of HUG1 rescues lethality of mec1Δ and suppresses dun1Δ strains. In this study, multiple approaches demonstrate the regulatory response of Hug1p to DNA damage and HU treatment and support its role as a negative effector of the MEC1 pathway. Consistent with our hypothesis, wild-type cells are sensitive to DNA damage and HU when HUG1 is overexpressed. A Hug1 polyclonal antiserum reveals that HUG1 encodes a protein in budding yeast and its MEC1-dependent expression is delayed compared to the rapid induction of Rnr3p in response to HU treatment. Cell biology and subcellular fractionation experiments show localization of Hug1p-GFP to the cytoplasm upon HU treatment. The cytoplasmic localization of Hug1p-GFP is dependent on MEC1 pathway genes and coincides with the cytoplasmic localization of Rnr2p–Rnr4p. Taken together, the genetic interactions, gene expression, and localization studies support a novel role for Hug1p as a negative regulator of the MEC1 checkpoint response through its compartmentalization with Rnr2p–Rnr4p.

Antimicrobial Agent of Susceptibilities and Antiseptic Resistance Gene Distribution among Methicillin-Resistant Staphylococcus aureus Isolates from Patients with Impetigo and Staphylococcal Scalded Skin Syndrome

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Noguchi, Norihisa; Nakaminami, Hidemasa; Nishijima, Setsuko; Kurokawa, Ichiro; So, Hiromu; Sasatsu, Masanori

2006-01-01

The susceptibilities to antimicrobial agents of and distributions of antiseptic resistance genes in methicillin-resistant Staphylococcus aureus (MRSA) strains isolated between 1999 and 2004 in Japan were examined. The data of MRSA strains that are causative agents of impetigo and staphylococcal scalded skin syndrome (SSSS) were compared with those of MRSA strains isolated from patients with other diseases. The susceptibilities to antiseptic agents in MRSA isolates from patients with impetigo and SSSS were higher than those in MRSA isolates from patients with other diseases. The distribution of the qacA/B genes in MRSA strains isolated from patients with impetigo and SSSS (1.3%, 1/76) was remarkably lower than that in MRSA strains isolated from patients with other diseases (45.9%, 95/207). Epidemiologic typings of staphylococcal cassette chromosome mec (SCCmec) and pulsed-field gel electrophoresis (PFGE) showed that MRSA strains isolated from patients with impetigo and SSSS had type IV SCCmec (75/76), except for one strain, and 64.5% (49/76) of the strains had different PFGE types. In addition, the patterns of restriction digestion of all tested qacA/B plasmid in MRSA isolates having different PFGE types were identical. The results showed that a specific MRSA clone carrying qacA/B was not prevalent, but qacA/B was spread among health care-associated MRSA strains. Therefore, it was concluded that the lower distribution rate of qacA/B resulted in higher susceptibilities to cationic antiseptic agents in MRSA isolated from patients with impetigo and SSSS. PMID:16757607

Temas de ventilación mecánica

OpenAIRE

Caballero López, Armando

2011-01-01

Se trata de la presentación de cinco capítulos del Tomo II del libro *TERAPIA INTENSIVA* muy íntimamente relacionados con la teoría y la práctica de la ventilación mecánica, incluyéndose una introducción con un análisis histórico de la ventilación mecánica y la evolución de conceptos recientes en la temática. Se usan como referencias bibliográficas la producción científica y experiencia del autor, relacionada con la temática que se trata. Los principales novedades y aportes son el conocimient...

A comprehensive review of microbial electrolysis cells (MEC reactor designs and configurations for sustainable hydrogen gas production

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Abudukeremu Kadier

2016-03-01

Full Text Available Hydrogen gas has tremendous potential as an environmentally acceptable energy carrier for vehicles. A cutting edge technology called a microbial electrolysis cell (MEC can achieve sustainable and clean hydrogen production from a wide range of renewable biomass and wastewaters. Enhancing the hydrogen production rate and lowering the energy input are the main challenges of MEC technology. MEC reactor design is one of the crucial factors which directly influence on hydrogen and current production rate in MECs. The rector design is also a key factor to up-scaling. Traditional MEC designs incorporated membranes, but it was recently shown that membrane-free designs can lead to both high hydrogen recoveries and production rates. Since then multiple studies have developed reactors that operate without membranes. This review provides a brief overview of recent advances in research on scalable MEC reactor design and configurations.

Several Virulence Factors of Multidrug-Resistant Staphylococcus aureus Isolates From Hospitalized Patients in Tehran

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Abdolmajid Ghasemian

2015-05-01

Full Text Available Background: Biofilm formation plays an important role in resistance of Staphylococcus aureus isolates; especially multidrug-resistant isolates are a threat to healthcare settings. Objectives: The aims of this study were to detect biofilm formation and presence of several related genes among multidrug-resistant (MDR isolates of Staphylococcus aureus. Patients and Methods: A total Of 209 S. aureus strains were isolated from patients and identified by conventional diagnostic tests. The multidrug-resistant MRSA isolates were detected by antibiotic susceptibility test. The phenotypic biofilm formation was detected by micro-titre tissue plate assay. The polymerase chain reaction (PCR was performed to detect the mecA, Staphylococcal Cassette Chromosome mec (SCCmec types, accessory gene regulatory (agr genes, the icaADBC and several genes encoding staphylococcal surface proteins including clfAB, fnbAB, fib, eno, can, ebps and bbp genes with specific primers. Results: Sixty-four (30.6% isolates were methicillin-resistant, among which thirty-six (56.2% were MDR. These isolates were resistant to amoxicillin, tetracycline, ciprofloxacin, gentamicin, erythromycin and trimethoprim-sulfamethoxazole (except to 6 isolates. All the isolates were susceptible to vancomycin and linezolid. All the MDR-MRSA harbored SCCmec type III. All the MDR- MRSA isolates were strong biofilm producers in the phenotypic test. The majority of MDR- MRSA was belonged to agrI (67%, n = 24, followed by agr II (17%, n = 6, agrIV (11%, n = 4 and agrIII (5.5%, n = 2. The frequency of icaADBC genes were 75% (n = 27, 61% (n = 22, 72% (n = 26 and 72% (n = 26, respectively. Furthermore, the prevalence of clfA, clfB, fnbA, fnbB, fib, can, eno, ebps and bbp genes was 100%, 100%, 67%, 56%, 80%, 63%, 78%, 7% and 0%, respectively. Furthermore, approximately all the MRSA was strong biofilm producers. Conclusions: Multidrug-resistant isolates produced biofilm strongly and the majority harbored most

Estudio de las propiedades mecánicas del sistema óseo (segunda parte)

OpenAIRE

Mendoza, Alvaro

2011-01-01

Los estudios se hicieron bajo la supervisión del área de Biomecánica. Los ensayos dieron a conocer los valores reales de los esfuerzos mecánicos que es capaz de resistir el tejido óseo. Se elaboraron curvas de esfuerzo-deformación, con la ayuda de deformímetros mecánicos y rosetas de deformación, encontrándose las diferentes propiedades mecánicas y dando una base sólida para estudios posteriores en el área, que ayuden aún más al desarrollo de la bioingeniería en Colombia.

Control of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak in a day-care institution

DEFF Research Database (Denmark)

Jensen, Jens Ulrik; Jensen, ET; Larsen, AR

2006-01-01

in the study: 38 children, 60 staff members and 12 close relatives of colonized subjects. Infection control measures included screening all individuals. When MRSA infection or colonization was found, an attempt was made to eradicate MRSA, staff education was undertaken and attempts were made to determine...... the route of transmission. Eleven individuals were found to be positive for MRSA (10.0%). All isolates were identical by pulsed-field gel electrophoresis and harboured the staphylococcal cassette chromosome mec (SCCmec) type IV. All colonized and infected individuals were associated with a single room...... in one of the institutions. MRSA was eradicated from all the colonized and infected subjects. This study shows that it is possible to control an MRSA outbreak in institutions for multi-handicapped children where there is a high degree of physical contact....

Algorítmica del diseño mecánico

OpenAIRE

José Martínez Escanaverino

1997-01-01

Se demuestra que cualquier procedimiento de diseño mecánico puede interpretarse como un proceso de solución de problemas sobre modelos matemáticos, lo cual equivale a la obtención de los algoritmos de solución de tales problemas. Se utilizan los grafos bicromáticos como medio de expresión de los modelos, problemas yalgoritmos. Se ilustran los conceptos teóricos con un ejemplo práctico tomado de la mecánica de los sólidos.

POTENTIAL USE OF MICROBIAL ELECTROLYSIS CELLS (MECs IN DOMESTIC WASTEWATER TREATMENT PLANTS FOR ENERGY RECOVERY

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Adrian eEscapa

2014-06-01

Full Text Available Globally, large amounts of electrical energy are spent every year for domestic wastewater (dWW treatment. In the future, energy prices are expected to rise as the demand for energy resources increases and fossil fuel reserves become depleted. By using appropriate technologies, the potential chemical energy contained in the organic compounds present in dWWs might help to improve the energy and economic balance of dWW treatment plants. Bioelectrochemical Systems (BESs in general and microbial electrolysis cells (MECs in particular represent an emerging technology capable of harvesting part of this energy. This study offers an overview of the potential of using MEC technology in dWW treatment plants (dWWTPs to reduce the energy bill. It begins with a brief account of the basics of BESs, followed by an examination of how MECs can be integrated in dWW treatment plants (dWWTPs, identifying scaling-up bottlenecks and estimating potential energy savings. A simplified analysis showed that the use of MEC technology may help to reduce up to ~20% the energy consumption in a conventional dWWTP. The study concludes with a discussion of the future perspectives of MEC technology for dWW treatment. The growing rates of municipal water and wastewater treatment markets in Europe offer excellent business prospects and it is expected that the first generation of MECs could be ready within 1-4 years. However, before MEC technology may achieve practical implementation in dWWTPs, it needs not only to overcome important techno-economic challenges, but also to compete with other energy-producing technologies.

Estudio de las propiedades mecánicas del sistema óseo (Segunda parte

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Alvaro Mendoza

1998-09-01

Full Text Available Los estudios se hicieron bajo la supervisión del área de Biomecánica. Los ensayos dieron a conocer los valores reales de los esfuerzos mecánicos que es capaz de resistir el tejido óseo. Se elaboraron curvas de esfuerzo-deformación, con la ayuda de deformímetros mecánicos y rosetas de deformación, encontrándose las diferentes propiedades mecánicas y dando una base sólida para estudios posteriores en el área, que ayuden aún más al desarrollo de la bioingeniería en Colombia.

Comportamiento mecánico de yeso reforzado con polímeros sintéticos

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García Santos, Alfonso

1988-01-01

Se presenta un estudio de la resistencia mecánica del yeso, basado en su refuerzo mediante la adición de polímeros sintéticos, en forma de fibras y dispersiones acuosas. Se pretende mejorar las características mecánicas del yeso, entre cuyas cualidades se pueden enumerar las siguientes: abundancia en España, bajo coste energético, manejabilidad y propiedades de habitabilidad (acústicas, higrotérmicas, etc.). El aumento de las características mecánicas del yeso permite su utilización como elem...

Antimicrobial resistance and virulence genes profiling of methicillin-resistant Staphylococcus aureus isolates in a burn center: A 5-year study.

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Jiang, Bei; Yin, Supeng; You, Bo; Gong, Yali; Huang, Guangtao; Yang, Zichen; Zhang, Yulong; Chen, Yu; Chen, Jing; Yuan, Zhiqiang; Hu, Xiaomei; Peng, Yizhi

2018-01-01

Methicillin-resistant S. aureus (MRSA) has attracted more and more attention in recent years, especially in burn medical centers. Here we conducted a 5-year period study to evaluate the MRSA infection in our burn center. The staphylococcal chromosomal cassette mec (SCCmec) typing, antimicrobials susceptibility and virulence profiles were also performed among the MRSA isolates. Of the 259 S. aureus isolates, 239 (92.28%) isolates were identified as MRSA. A decreased trend of MRSA isolation rate over time was found (P = 0.0063). Majority of MRSA isolates in our center belonged to SCCmec type III (230/239, 96.23%). Antimicrobials susceptibility tests of the MRSA isolates revealed significantly decreased resistance to clindamycin (P = 0.0183), and increased resistance to chloramphenicol (P = 0.0020) and minocycline (P Virulence factors profiling showed that most of MRSA isolates in our center carried the virulence factor pattern of cna-clfA-clfB-eno-fib-icaA-icaD-sea-psmα-lukED-hlg-hlgv-hla-hld (214/239, 89.54%). In conclusion, our study suggests that MRSA infection is serious in our burn center, but presented decreased trend over time. Most of MRSA isolates in our center presented the same virulence factor profile. More attention should be attached to nosocomial infection in burn medical center. Antimicrobials susceptibility changing over time was observed. Antimicrobials susceptibility monitoring is necessary and helps to select appropriate drugs against MRSA infections. Copyright © 2017. Published by Elsevier Ltd.

Antimicrobial resistance and population structure of Staphylococcus epidermidis recovered from animals and humans.

Science.gov (United States)

Argudín, M Angeles; Vanderhaeghen, Wannes; Vandendriessche, Stien; Vandecandelaere, Ilse; André, François-Xavier; Denis, Olivier; Coenye, Tom; Butaye, Patrick

2015-07-09

While Staphylococcus epidermidis, as part of the commensal flora, is a well-known human opportunistic pathogen, only little is known about the genetic relatedness of S. epidermidis carriage isolates from animal and human origin. This study aimed to compare S. epidermidis recovered from livestock, livestock-farmers and humans associated with the hospital environment. A total of 193 S. epidermidis isolates from three populations [animals (n=33), farmers (n=86) and hospital-associated (n=74)] were characterized by broth microdilution antimicrobial susceptibility testing, staphylococcal cassette chromosome mec (SCCmec) typing, pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The overall S. epidermidis nasal colonization rate was low in animals (1-9%) but high among farmers (75%). High levels of multi-resistance were found in all populations. Tetracycline resistance was high in animal and farmer isolates; resistance to erythromycin, clindamycin and trimethoprim was high in animal and hospital-associated isolates. Methicillin-resistant S. epidermidis - MRSE isolates were found in all collections, with 22 (67%) MRSE in animals, 44 (51%) MRSE in farmers and 42 (57%) MRSE associated with the hospital-setting. Known SCCmec types and variants were detected in 79% of MRSE; the rest were non-typeable cassettes. In total 79 PFGE-types were found, of which 22 were shared between livestock, farmers and the hospital settings. Clonal complex 2 was predominant in all three populations and most STs corresponded to types previously observed in community and nosocomial S. epidermidis populations. S. epidermidis isolates from livestock, farmers and hospital-setting showed a high level of diversity, but some clones can be found in humans as well as in animals. Copyright © 2015 Elsevier B.V. All rights reserved.

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Fernanda Sampaio Cavalcante

2013-01-01

Full Text Available INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA can be difficult to detect at the clinical practice. METHODS: We analyzed 140 MRSA isolates from inpatients to correlate the antimicrobial susceptibility with the SCCmec types. RESULTS: Type III (n = 63 isolates were more resistant to ciprofloxacin, clindamycin, cloramphenicol, erythromycin, gentamicin, and rifampin than type IV (n = 65 ones (p CONCLUSIONS: In regions where these SCCmec types are prevalent, the detection of specific resistant phenotypes could help to predict them, mainly when there are no technical conditions to SCCmec typing.

Dissemination of Methicillin-Resistant Staphylococcus aureus (MRSA), USA300 Sequence Type 8 Lineage in Latin-America

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Reyes, Jinnethe; Rincón, Sandra; Díaz, Lorena; Panesso, Diana; Contreras, Germán A.; Zurita, Jeannete; Carrillo, Carlos; Rizzi, Adele; Guzmán, Manuel; Adachi, Javier; Chowdhury, Shahreen; Murray, Barbara E.; Arias, Cesar A.

2009-01-01

Background Methicillin-resistant Staphylococus aureus (MRSA) is an important nosocomial and community-associated (CA) pathogen. Recently, a variant of the MRSA USA300 clone emerged and disseminated in South-America causing important clinical problems. Methods S. aureus isolates were prospectively collected (2006 to 2008) from 32 tertiary hospitals in Colombia, Ecuador, Peru, and Venezuela. MRSA isolates were subjected to antimicrobial susceptibility testing, pulsed field gel electrophoresis (PFGE), and categorized as healthcare-associated (HA)-like or CA-like clones based on genotypic characteristics and detection of genes encoding the Panton-Valentine leukocidin (PVL) and staphylococcal cassette mec (SCCmec) IV. Additionally, MLST of representative isolates of each major CA-MRSA pulsotype, and detection of USA300-associated toxins and the arcA gene were performed in all isolates categorized as CA-MRSA. Results A total of 1570 S. aureus were included; 651 were MRSA (41%), with the highest rates of MRSA isolation in Peru (62%), and lowest in Venezuela (26%) and 71%, 27%, and 2% were classified as HA-like, CA-like, and non-CA/HA-like clones, respectively. Only 9 MRSA isolates were confirmed to have reduced susceptibility to glycopeptides (GISA phenotype). The most common pulsotype (designated ComA) amongst the CA-like MRSA strains was found in 96% of isolates with the majority (81%) having ≤6 bands difference with the USA300-0114 strain. Representative isolates of this clone were ST8 but, unlike the USA300-0114 strain, they harbored a different SCCmec IV subtype and lacked arcA (an indicator of the arginine catabolic mobile element (ACME)). Conclusion A variant CA-MRSA USA300 clone has now become established in South America and, in some countries, is endemic in hospital settings. PMID:19911971

Complicaciones pulmonares asociadas a ventilación mecánica en el paciente neonatal

OpenAIRE

Cristabel Torres-Castro; Jaime Valle-Leal; Alba J. Martínez-Limón; Zaira Lastra-Jiménez; Lesvia Carmina Delgado-Bojórquez

2016-01-01

Introducción: Se buscó determinar la incidencia de complicaciones pulmonares asociadas a ventilación mecánica en pacientes ingresados a un servicio de cuidados intensivos neonatales (UCIN) en un hospital de 2° nivel. Metodología: Estudio analítico retrospectivo en expedientes de recién nacidos ingresados a una sala de UCIN y que recibieron ventilación mecánica en un hospital de segundo nivel de atención médica. Se recabaron datos demográficos, de la ventilación mecánica, la intubación y co...

Prevalence and molecular characteristics of Staphylococcus aureus, including methicillin resistant strains, isolated from bulk can milk and raw milk products in pastoral communities of South-West Uganda.

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Asiimwe, Benon B; Baldan, Rossella; Trovato, Alberto; Cirillo, Daniela M

2017-06-13

Staphylococcus aureus strains are now regarded as zoonotic agents. In pastoral settings where human-animal interaction is intimate, multi-drug resistant microorganisms have become an emerging zoonotic issue of public health concern. The study of S. aureus prevalence, antimicrobial resistance and clonal lineages in humans, animals and food in African settings has great relevance, taking into consideration the high diversity of ethnicities, cultures and food habits that determine the lifestyle of the people. Little is known about milk carriage of methicillin resistant S. aureus strains (MRSA) and their virulence factors in Uganda. Here, we present the prevalence of MRSA in bulk can milk and raw milk products in pastoral communities of south-west Uganda. We also present PFGE profiles, spa-types, as well as frequency of enterotoxins genes. S. aureus was identified by the coagulase test, susceptibility testing by the Kirby-Bauer disc diffusion and E-test methods and MRSA by detection of the mecA gene and SCCmec types. The presence of Panton - Valentine Leucocidin (PVL) genes and staphylococcal enterotoxins was determined by PCR, while genotyping was by PFGE and spa typing. S. aureus were isolated from 30/148 (20.3%) milk and 11/91(12%) sour milk samples. mecA gene carriage, hence MRSA, was detected in 23/41 (56.1%) of the isolates, with 21 of the 23 (91.3%) being SCCmec type V; while up to 30/41 (73.2%) of the isolates were resistant to tetracycline. Only five isolates carried the PVL virulence gene, while PFGE typing revealed ten clusters (ranging from two seven isolates each) that comprised 83% of the sample, and only eight isolates with unique pulsotypes. The largest PFGE profile (E) consisted of seven isolates while t7753, t1398, and t2112 were the most common spa-types. Thirty seven of the 41 strains (90.2%) showed at least one of the eight enterotoxin genes tested, with sem 29 (70.7%), sei 25 (61%) and seg 21 (51.2%) being the most frequently observed genes. This

Livestock-Associated Methicillin Resistant and Methicillin Susceptible Staphylococcus aureus Sequence Type (CC)1 in European Farmed Animals: High Genetic Relatedness of Isolates from Italian Cattle Herds and Humans

DEFF Research Database (Denmark)

Alba, Patricia; Feltrin, Fabiola; Cordaro, Gessica

2015-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) Sequence Type (ST)1, Clonal Complex( CC) 1, SCCmec V is one of the major Livestock-Associated (LA-) lineages in pig farming industry in Italy and is associated with pigs in other European countries. Recently, it has been increasingly detected...... in Italian dairy cattle herds. The aim of this study was to analyse the differences between ST1 MRSA and methicillin-susceptible S. aureus (MSSA) from cattle and pig herds in Italy and Europe and human isolates. Sixty-tree animal isolates from different holdings and 20 human isolates were characterized...... by pulsed-field gel electrophoresis (PFGE), spa-typing, SCCmec typing, and by micro-array analysis for several virulence, antimicrobial resistance, and strain/host-specific marker genes. Three major PFGE clusters were detected. The bovine isolates shared a high (>= 90% to 100%) similarity with human...

Antimicrobial susceptibility of methicillin-resistant Staphylococcus pseudintermedius isolated from veterinary clinical cases in the UK.

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Maluping, R P; Paul, N C; Moodley, A

2014-01-01

Staphylococcus pseudintermedius is a leading aetiologic agent of pyoderma and other body tissue infections in dogs and cats. In recent years, an increased prevalence of methicillin-resistant S. pseudintermedius (MRSP) has been reported. Isolation of MRSP in serious infections poses a major therapeutic challenge as strains are often resistant to all forms of systemic antibiotic used to treat S. pseudintermedius -related infections. This study investigates the occurrence of MRSP from a total of 7183 clinical samples submitted to the authors' laboratories over a 15-month period. Identification was based on standard microbiological identification methods, and by S. pseudintermedius-specific nuc polymerase chain reaction (PCR). Methicillin resistance was confirmed by PBP2a latex agglutination and mecA PCR. Susceptibility against non-beta-lactam antibiotics was carried out using a disc-diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. In addition, susceptibility to pradofloxacin--a new veterinary fluoroquinolone--was also investigated. SCCmec types were determined by multiplex PCR. Staphylococcus pseudintermedius was isolated from 391 (5%) samples and 20 were confirmed as MRSP from cases of pyoderma, otitis, wound infections, urinary tract infection and mastitis in dogs only. All 20 isolates were resistant to clindamycin and sulphamethoxazole/trimethoprim. Nineteen were resistant to chloramphenicol, enrofloxacin, gentamicin, marbofloxacin and pradofloxacin; additionally, seven isolates were resistant to tetracycline. Fifteen isolates carried SCCmec type II-III, four isolates had type V and one harboured type IV. To date, only a few scientific papers on clinical MRSP strains isolated from the UK have been published, thus the results from this study would provide additional baseline data for further investigations.

Requirement of the Mre11 complex and exonuclease 1 for activation of the Mec1 signaling pathway.

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Nakada, Daisuke; Hirano, Yukinori; Sugimoto, Katsunori

2004-11-01

The large protein kinases, ataxia-telangiectasia mutated (ATM) and ATM-Rad3-related (ATR), orchestrate DNA damage checkpoint pathways. In budding yeast, ATM and ATR homologs are encoded by TEL1 and MEC1, respectively. The Mre11 complex consists of two highly related proteins, Mre11 and Rad50, and a third protein, Xrs2 in budding yeast or Nbs1 in mammals. The Mre11 complex controls the ATM/Tel1 signaling pathway in response to double-strand break (DSB) induction. We show here that the Mre11 complex functions together with exonuclease 1 (Exo1) in activation of the Mec1 signaling pathway after DNA damage and replication block. Mec1 controls the checkpoint responses following UV irradiation as well as DSB induction. Correspondingly, the Mre11 complex and Exo1 play an overlapping role in activation of DSB- and UV-induced checkpoints. The Mre11 complex and Exo1 collaborate in producing long single-stranded DNA (ssDNA) tails at DSB ends and promote Mec1 association with the DSBs. The Ddc1-Mec3-Rad17 complex associates with sites of DNA damage and modulates the Mec1 signaling pathway. However, Ddc1 association with DSBs does not require the function of the Mre11 complex and Exo1. Mec1 controls checkpoint responses to stalled DNA replication as well. Accordingly, the Mre11 complex and Exo1 contribute to activation of the replication checkpoint pathway. Our results provide a model in which the Mre11 complex and Exo1 cooperate in generating long ssDNA tracts and thereby facilitate Mec1 association with sites of DNA damage or replication block.

Apuntes de Mecánica de Fluidos

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Martín Domingo, Agustín

2011-01-01

Esta publicacion contiene unos apuntes para la parte de Mecánica de Fluidos de las asignaturas de la ETSAM, junto con cierta cantidad de material adicional que excede el ámbito del curso. Aunque está lejos de ser completa y de estar libre de errores, el autor espera sea útil.

Epidemiology of Staphylococcus aureus harboring the mecA or Panton-Valentine leukocidin genes in hospitals in Java and Bali, Indonesia.

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Santosaningsih, Dewi; Santoso, Sanarto; Budayanti, Nyoman S; Kuntaman, Kuntaman; Lestari, Endang S; Farida, Helmia; Hapsari, Rebriarina; Hadi, Purnomo; Winarto, Winarto; Milheiriço, Catarina; Maquelin, Kees; Willemse-Erix, Diana; van Belkum, Alex; Severin, Juliëtte A; Verbrugh, Henri A

2014-04-01

Data of Staphylococcus aureus carriage in Indonesian hospitals are scarce. Therefore, the epidemiology of S. aureus among surgery patients in three academic hospitals in Indonesia was studied. In total, 366 of 1,502 (24.4%) patients carried S. aureus. The methicillin-resistant S. aureus (MRSA) carriage rate was 4.3%, whereas 1.5% of the patients carried Panton-Valentine leukocidin (PVL)-positive methicillin-sensitive S. aureus (MSSA). Semarang and Malang city (odds ratio [OR] 9.4 and OR 9.0), being male (OR 2.4), hospitalization for more than 5 days (OR 11.708), and antibiotic therapy during hospitalization (OR 2.6) were independent determinants for MRSA carriage, whereas prior hospitalization (OR 2.5) was the only one risk factor for PVL-positive MSSA carriage. Typing of MRSA strains by Raman spectroscopy showed three large clusters assigned type 21, 24, and 38, all corresponding to ST239-MRSA-SCCmec type III. In conclusion, MRSA and PVL-positive MSSA are present among patients in surgical wards in Indonesian academic hospitals.

Community-acquired necrotizing pneumonia caused by methicillin-resistant Staphylococcus aureus ST30-SCCmecIVc-spat019-PVL positive in San Antonio de Areco, Argentina

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Silvina Fernández

2015-03-01

Full Text Available Community-acquired methicillin-resistant Staphylococcus aureus is the first cause of skin and soft tissue infections, but can also produce severe diseases such as bacteremia, osteomyelitis and necrotizing pneumonia. Some S. aureus lineages have been described in cases of necrotizing pneumonia worldwide, usually in young, previously healthy patients. In this work, we describe a fatal case of necrotizing pneumonia due to community-acquired methicillin-resistant S. aureus clone ST30-SCCmecIVc-spat019-PVL positive in an immunocompetent adult patient.

Research Progress of Hydrogen Production fromOrganic Wastes in Microbial Electrolysis Cell(MEC

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YU Yin-sheng

2015-08-01

Full Text Available Microbial electrolysis cell(MECtechnology as an emerging technology, has achieved the target of hydrogen production from different substrates such as waste water, forestry wastes, activated sludge by simultaneous enzymolysis and fermentation, which can effectively improve the efficiency of resource utilization. This paper described the working principle of MEC and analyzed these factors influencing the process of hydrogen production from organic waste in MEC.

Colonization of butchers with livestock-associated methicillin-resistant Staphylococcus aureus.

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Boost, M; Ho, J; Guardabassi, L; O'Donoghue, M

2013-12-01

Reports have documented colonization of swine in Europe, North America and more recently in China with livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA). Contamination of pig farmers, veterinarians and abattoir workers with these strains has been observed. However, although contamination levels of 10% of retail pork were reported from the Netherlands and Canada, there are limited data of contamination rates of workers handling raw meat. We investigated the rates of MRSA contamination of local butchers working in wet markets, where recently slaughtered pigs are cut up. Nasal swabs collected from 300 pork butchers at markets throughout Hong Kong were enriched in brain heart infusion broth with 5% salt and cultured on MRSASelect(®) . Isolates were confirmed as Staphylococcus aureus and susceptibility testing performed. The presence of mecA was confirmed, SCCmec and spa type determined and relatedness investigated by PFGE. Subjects completed a questionnaire on MRSA carriage risk factors. Seventeen samples (5.6%) yielded MRSA, 15 harbouring SCCmec IVb. Ten strains were t899 (CC9), previously reported from local pig carcasses. Five strains were healthcare associated: SCCmec type II, t701(CC6), colonizing two subjects at the same establishment, and single isolates of t008 (CC8), t002 (CC5) and t123 (CC45). The remaining isolates were t359 (CC97), previously reported from buffaloes, and t375 (CC5), reported from bovine milk. None of these butchers reported recent hospitalization or a healthcare worker in the family. Two had recently received antibiotics, one for a skin infection. Four reported wound infections within the last year. All were exposed to meat for >9 h per day. Carriage of MRSA was higher in butchers than in the general community. Although five strains were probably of healthcare origin, the high incidence of t899 (CC9) suggests that cross-contamination from pork occurs frequently. Washing of hands after touching raw pork is advised

Evidence for the evolutionary steps leading to mecA-mediated β-lactam resistance in staphylococci

DEFF Research Database (Denmark)

Rolo, Joana; Worning, Peder; Boye Nielsen, Jesper

2017-01-01

the most primitive staphylococci. In this study we aimed to identify evolutionary steps linking these mecA precursors to the β-lactam resistance gene mecA and the resistance phenotype. We sequenced genomes of 106 S. sciuri, S. vitulinus and S. fleurettii strains and determined their oxacillin...

Typing of Panton-Valentine Leukocidin-Encoding Phages and lukSF-PV Gene Sequence Variation in Staphylococcus aureus from China.

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Zhao, Huanqiang; Hu, Fupin; Jin, Shu; Xu, Xiaogang; Zou, Yuhan; Ding, Baixing; He, Chunyan; Gong, Fang; Liu, Qingzhong

2016-01-01

Panton-Valentine leukocidin (PVL, encoded by lukSF-PV genes), a bi-component and pore-forming toxin, is carried by different staphylococcal bacteriophages. The prevalence of PVL in Staphylococcus aureus has been reported around the globe. However, the data on PVL-encoding phage types, lukSF-PV gene variation and chromosomal phage insertion sites for PVL-positive S. aureus are limited, especially in China. In order to obtain a more complete understanding of the molecular epidemiology of PVL-positive S. aureus, an integrated and modified PCR-based scheme was applied to detect the PVL-encoding phage types. Phage insertion locus and the lukSF-PV variant were determined by PCR and sequencing. Meanwhile, the genetic background was characterized by staphylococcal cassette chromosome mec (SCCmec) typing, staphylococcal protein A (spa) gene polymorphisms typing, pulsed-field gel electrophoresis (PFGE) typing, accessory gene regulator (agr) locus typing and multilocus sequence typing (MLST). Seventy eight (78/1175, 6.6%) isolates possessed the lukSF-PV genes and 59.0% (46/78) of PVL-positive strains belonged to CC59 lineage. Eight known different PVL-encoding phage types were detected, and Φ7247PVL/ΦST5967PVL (n = 13) and ΦPVL (n = 12) were the most prevalent among them. While 25 (25/78, 32.1%) isolates, belonging to ST30, and ST59 clones, were unable to be typed by the modified PCR-based scheme. Single nucleotide polymorphisms (SNPs) were identified at five locations in the lukSF-PV genes, two of which were non-synonymous. Maximum-likelihood tree analysis of attachment sites sequences detected six SNP profiles for attR and eight for attL, respectively. In conclusion, the PVL-positive S. aureus mainly harbored Φ7247PVL/ΦST5967PVL and ΦPVL in the regions studied. lukSF-PV gene sequences, PVL-encoding phages, and phage insertion locus generally varied with lineages. Moreover, PVL-positive clones that have emerged worldwide likely carry distinct phages.

Typing of Panton-Valentine Leukocidin-encoding Phages and lukSF-PV Gene Sequence Variation in Staphylococcus aureus from China

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Huanqiang Zhao

2016-08-01

Full Text Available Panton-Valentine leucocidin (PVL, encoded by lukSF-PV genes, a bi-component and pore-forming toxin, is carried by different staphylococcal bacteriophages. The prevalence of PVL in Staphylococcus aureus (S. aureus have been reported around the globe. However, the data on PVL-encoding phage types, lukSF-PV gene variation and chromosomal phage insertion sites for PVL-positive S. aureus are limited, especially in China. In order to obtain a more complete understanding of the molecular epidemiology of PVL-positive S. aureus, an integrated and modified PCR-based scheme was applied to detect the PVL-encoding phage types. Phage insertion locus and the lukSF-PV variant were determined by PCR and sequencing. Meanwhile, the genetic background was characterized by staphylococcal cassette chromosome mec (SCCmec typing, staphylococcal protein A (spa gene polymorphisms typing, pulsed-field gel electrophoresis (PFGE typing, accessory gene regulator (agr locus typing and multilocus sequence typing (MLST. Seventy eight (78/1175, 6.6% isolates possessed the lukSF-PV genes and 59.0% (46/78 of PVL-positive strains belonged to CC59 lineage. Eight known different PVL-encoding phage types were detected, and Φ7247PVL/ΦST5967PVL (n=13 and ΦPVL (n=12 were the most prevalent among them. While 25 (25/78, 32.1% isolates, belonging to ST30 and ST59 clones, were unable to be typed by the modified PCR-based scheme. Single nucleotide polymorphisms (SNPs were identified at five locations in the lukSF-PV genes, two of which were non-synonymous. Maximum-likelihood tree analysis of attachment sites sequences detected six SNP profiles for attR and eight for attL, respectively. In conclusion, the PVL-positive S. aureus mainly harbored Φ7247PVL/ΦST5967PVL and ΦPVL in the regions studied. lukSF-PV gene sequences, PVL-encoding phages and phage insertion locus generally varied with lineages. Moreover, PVL-positive clones that have emerged worldwide likely carry distinct phages.

Structural Basis of Mec1-Ddc2-RPA Assembly and Activation on Single-Stranded DNA at Sites of Damage.

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Deshpande, Ishan; Seeber, Andrew; Shimada, Kenji; Keusch, Jeremy J; Gut, Heinz; Gasser, Susan M

2017-10-19

Mec1-Ddc2 (ATR-ATRIP) is a key DNA-damage-sensing kinase that is recruited through the single-stranded (ss) DNA-binding replication protein A (RPA) to initiate the DNA damage checkpoint response. Activation of ATR-ATRIP in the absence of DNA damage is lethal. Therefore, it is important that damage-specific recruitment precedes kinase activation, which is achieved at least in part by Mec1-Ddc2 homodimerization. Here, we report a structural, biochemical, and functional characterization of the yeast Mec1-Ddc2-RPA assembly. High-resolution co-crystal structures of Ddc2-Rfa1 and Ddc2-Rfa1-t11 (K45E mutant) N termini and of the Ddc2 coiled-coil domain (CCD) provide insight into Mec1-Ddc2 homodimerization and damage-site targeting. Based on our structural and functional findings, we present a Mec1-Ddc2-RPA-ssDNA composite structural model. By way of validation, we show that RPA-dependent recruitment of Mec1-Ddc2 is crucial for maintaining its homodimeric state at ssDNA and that Ddc2's recruitment domain and CCD are important for Mec1-dependent survival of UV-light-induced DNA damage. Copyright © 2017 Elsevier Inc. All rights reserved.

Factors associated with the occurrence of MRSA CC398 in herds of fattening pigs in Germany

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Alt Katja

2011-11-01

Full Text Available Abstract Background The purpose of this study was to investigate the prevalence of MRSA in herds of fattening pigs in different regions of Germany, and to determine factors associated with the occurrence of this pathogen. For this purpose pooled dust samples were collected, and a questionnaire covered information regarding herd characteristics and management practices. Samples were pre-enriched in high-salt medium followed by selective enrichment containing cefoxitin/aztreonam, and culturing. Presumptive colonies were confirmed by multiplex-PCR targeting nuc-, mecA- and 16S rRNA-genes. Isolates were spa- and SCCmec-, and in selected cases, multilocus sequence-typed. Susceptibilities to 13 antimicrobials were determined by broth microdilution. Statistical analysis was carried out using backward stepwise logistic regression to calculate odds ratios with the MRSA test result as the outcome and herd characteristics as categorical covariates. Results Overall, 152 of 290 (52% fattening pig farms tested positive for MRSA. The prevalence in the east, north- and south-west of Germany ranged from 39 to 59%. t011 (66% and t034 (23% were the most commonly identified spa-types, and 85% of isolates carried SCCmec Type V. Identified spa-types were all associated with clonal complex CC398. Susceptibility testing revealed that all isolates were resistant to tetracycline. High resistance rates were also found for sulfamethoxazole/trimethoprim (40%, and quinupristin/dalfopristin (32%. In addition, 83% of strains displayed multidrug resistant (> 3 substance classes phenotypes. Logistic regression revealed herd size (large farms OR: 5.4; CI: 2.7-11.2; p Conclusions MRSA CC398 is widely distributed among herds of fattening pigs in Germany. Farm management plays a crucial role in the dissemination of MRSA with herd size, and production type representing potential major indicators.

Factors associated with the occurrence of MRSA CC398 in herds of fattening pigs in Germany.

Science.gov (United States)

Alt, Katja; Fetsch, Alexandra; Schroeter, Andreas; Guerra, Beatriz; Hammerl, Jens A; Hertwig, Stefan; Senkov, Natalja; Geinets, Anna; Mueller-Graf, Christine; Braeunig, Juliane; Kaesbohrer, Annemarie; Appel, Bernd; Hensel, Andreas; Tenhagen, Bernd-Alois

2011-11-10

The purpose of this study was to investigate the prevalence of MRSA in herds of fattening pigs in different regions of Germany, and to determine factors associated with the occurrence of this pathogen. For this purpose pooled dust samples were collected, and a questionnaire covered information regarding herd characteristics and management practices. Samples were pre-enriched in high-salt medium followed by selective enrichment containing cefoxitin/aztreonam, and culturing. Presumptive colonies were confirmed by multiplex-PCR targeting nuc-, mecA- and 16S rRNA-genes. Isolates were spa- and SCCmec-, and in selected cases, multilocus sequence-typed. Susceptibilities to 13 antimicrobials were determined by broth microdilution. Statistical analysis was carried out using backward stepwise logistic regression to calculate odds ratios with the MRSA test result as the outcome and herd characteristics as categorical covariates. Overall, 152 of 290 (52%) fattening pig farms tested positive for MRSA. The prevalence in the east, north- and south-west of Germany ranged from 39 to 59%.t011 (66%) and t034 (23%) were the most commonly identified spa-types, and 85% of isolates carried SCCmec Type V. Identified spa-types were all associated with clonal complex CC398. Susceptibility testing revealed that all isolates were resistant to tetracycline. High resistance rates were also found for sulfamethoxazole/trimethoprim (40%), and quinupristin/dalfopristin (32%). In addition, 83% of strains displayed multidrug resistant (> 3 substance classes) phenotypes.Logistic regression revealed herd size (large farms OR: 5.4; CI: 2.7-11.2; p pig operations. MRSA CC398 is widely distributed among herds of fattening pigs in Germany. Farm management plays a crucial role in the dissemination of MRSA with herd size, and production type representing potential major indicators.

Short communication: Characterization of methicillin-resistant Staphylococcus aureus isolated from raw milk fresh cheese in Colombia.

Science.gov (United States)

Herrera, Fanny C; García-López, María-Luisa; Santos, Jesús A

2016-10-01

The aim of this study was the characterization of a collection of 8 methicillin-resistant Staphylococcus aureus (MRSA) isolates, obtained from samples of fresh cheese (Doble Crema) produced from raw cow milk in small dairies in Colombia. All the isolates harbored the mecA and Panton-Valentine leukocidin (PVL) genes, presented with SCCmec type IV, and belonged to multilocus sequence type 8 and spa type 024. Seven isolates presented 3 closely related pulsed-field gel electrophoresis profiles. Three of them carried the staphylococcal enterotoxin B gene. The isolates were resistant to cefoxitin, oxacillin, penicillin, and ampicillin and susceptible to all non-β-lactams antibiotics tested, with minimum inhibitory concentration values for oxacillin of 4 to 8mg/L. The isolates belonged to the community-acquired MRSA group, suggesting a human source of contamination. The risk of human infection by MRSA via contaminated foods is considered low, but contaminated food commodities can contribute to the worldwide dissemination of clones of community-acquired MRSA. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Distribution and characterization of methicillin-resistant Staphylococcus aureus (MRSA) at the small animal hospital, faculty of veterinary medicine, Chiang Mai University, Thailand.

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Patchanee, Prapas; Tadee, Pakpoom; Ingkaninan, Pimlada; Tankaew, Pallop; Hoet, Armando E; Chupia, Vena

2014-03-01

Of 416 samples taken from veterinary staff (n = 30), dogs (n = 356) and various environmental sites (n = 30) at the Small Animal Hospital, Faculty of Veterinary Medicine, Chiang Mai University, Thailand, 13 samples contained methicillin-resistant Staphylococcus aureus (MRSA), of which 1 (SCCmec type II) came from veterinarian, 9 (SCCmec types I, III, IVa, V and untypeable) from dogs, and 3 (SCCmec types I, III, and IVb) from environmental samples. The MRSA isolates were 100% susceptible to vancomycin (100%), 69% to cephazolin and 62% to gentamicin, but were up to 92% resistant to tetracycline group, 69% to trimethoprim-sulfamethoxazoles and 62% to ceftriaxone. In addition, all MRSA isolates showed multidrug resistance. As the MRSA isolates from the veterinary staff and dogs were of different SCCmec types, this suggests there were no cross-infections. However, environmental contamination appears to have come from dogs, and appropriate hygienic practices should be introduced to solve this problem.

Evaluation of pharmaceuticals in surface water: reliability of PECs compared to MECs.

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Celle-Jeanton, Hélène; Schemberg, Dimitri; Mohammed, Nabaz; Huneau, Frédéric; Bertrand, Guillaume; Lavastre, Véronique; Le Coustumer, Philippe

2014-12-01

Due to the current analytical processes that are not able to measure all the pharmaceutical molecules and to the high costs and the consumption of time to sample and analyze PhACs, models to calculate Predicted Environmental Concentrations (PECs) have been developed. However a comparison between MECs and PECs, taking into account the methods of calculations and peculiarly the parameters included in the calculation (consumption data, pharmacokinetic parameters, elimination rate in STPs and in the environment), is necessary to assess the validity of PECs. MEC variations of sixteen target PhACs [acetaminophen (ACE), amlodipine (AML), atenolol (ATE), caffeine (CAF), carbamazepine (CAR), doxycycline (DOX), epoxycarbamazepine (EPO), fluvoxamine (FLU), furosemide (FUR), hydrochlorothiazide (HYD), ifosfamide (IFO), losartan (LOS), pravastatin (PRA), progesterone (PROG), ramipril (RAM), trimetazidine (TRI)] have been evaluated during one hydrological cycle, from October 2011 to October 2012 and compared to PECs calculated by using an adaptation of the models proposed by Heberer and Feldmann (2005) and EMEA (2006). Comparison of PECs and MECS has been achieved for six molecules: ATE, CAR, DOX, FUR, HYD and PRA. DOX, FUR and HYD present differences between PECs and MECs on an annual basis but their temporal evolutions follow the same trends. PEC evaluation for these PhACs could then be possible but need some adjustments of consumption patterns, pharmacokinetic parameters and/or mechanisms of (bio)degradation. ATE, CAR and PRA are well modeled; PECs can then be used as reliable estimation of concentrations without any reserve. Copyright © 2014 Elsevier Ltd. All rights reserved.

Public health officials and MECs should be held liable for harm ...

African Journals Online (AJOL)

Public health officials and MECs should be held liable for harm caused to patients through incompetence, indifference, maladministration or negligence regarding the availability of hospital equipment.

Methicillin-resistant Staphylococcus aureus in cows with mastitis, the presence of the mecA gene and the gene for virulence

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Vesna Jaki Tkalec

2015-11-01

Full Text Available The physiological properties of 47 Staphylococcus aureus strains were investigated. The test strains were grown on bacteriological media and identified by the ID32 STAF system for biochemical identification of bacteria. Sensitivity to antimicrobial agents was performed by the disc diffusion method. The nuc gene and the virulence factors coa, hla, hlb, hld, hlg, hlg-2, tst, eta, etb, lukF-PV and lukS-PV and mecA gene were detected by the polymerase chain reaction. Furthermore, the spa type of the studied isolates was also set. According to the obtained results, all strains had the nuc, coa, hla and hld gene. Ten strains (21.3 % had also the tst gene, while 37 strains (78.7 % had the hlg gene and 35 strains (74.5 % had the hlb and hlg-2 genes. All of the investigated S. aureus isolates were penicillin resistant (100 %, with 29 strains which were also resistant to oxacillin (61.7 %. Methicillin (oxacillin resistance was detected by the mecA gene detection, which is also the first MRSA result from the secretion samples of cows’ mammary glands in Croatia. The researched MRSA strains proved to belong to different spa types, and the most common were spa types t005, t011 and t521, and a new spa type t9498 was detected.

RNA-processing proteins regulate Mec1/ATR activation by promoting generation of RPA-coated ssDNA.

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Manfrini, Nicola; Trovesi, Camilla; Wery, Maxime; Martina, Marina; Cesena, Daniele; Descrimes, Marc; Morillon, Antonin; d'Adda di Fagagna, Fabrizio; Longhese, Maria Pia

2015-02-01

Eukaryotic cells respond to DNA double-strand breaks (DSBs) by activating a checkpoint that depends on the protein kinases Tel1/ATM and Mec1/ATR. Mec1/ATR is activated by RPA-coated single-stranded DNA (ssDNA), which arises upon nucleolytic degradation (resection) of the DSB. Emerging evidences indicate that RNA-processing factors play critical, yet poorly understood, roles in genomic stability. Here, we provide evidence that the Saccharomyces cerevisiae RNA decay factors Xrn1, Rrp6 and Trf4 regulate Mec1/ATR activation by promoting generation of RPA-coated ssDNA. The lack of Xrn1 inhibits ssDNA generation at the DSB by preventing the loading of the MRX complex. By contrast, DSB resection is not affected in the absence of Rrp6 or Trf4, but their lack impairs the recruitment of RPA, and therefore of Mec1, to the DSB. Rrp6 and Trf4 inactivation affects neither Rad51/Rad52 association nor DSB repair by homologous recombination (HR), suggesting that full Mec1 activation requires higher amount of RPA-coated ssDNA than HR-mediated repair. Noteworthy, deep transcriptome analyses do not identify common misregulated gene expression that could explain the observed phenotypes. Our results provide a novel link between RNA processing and genome stability. © 2014 The Authors.

Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in Horses, Cats, and Dogs Over a 5-Year Period in France

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Marisa Haenni

2017-12-01

Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA has been reported as a worldwide pathogen in humans and animals including companion animals, i.e., cats, dogs, and horses. France lacked a comprehensive nationwide study describing the molecular features of MRSA circulating among companion animals over a large period of time. Here is reported the characterization of 130 non-duplicate clinical MRSA isolates collected from those three animal species from 2010 to 2015 through the French national Resapath network. Characterization of isolates was performed using phenotypic (antimicrobial susceptibility tests and molecular (DNA arrays, spa-typing methods. A horse-specific epidemiology was observed in France with the large dissemination of a unique clone, the CC398 clone harboring a Staphylococcal chromosomal cassette mec (SCCmec type IV and spa-type t011. It was even the unique clone collected in 2015 whereas the clone CC8 USA500 (SCCmec type IV, classically described in horses, was present until 2014. Contrarily, cats and dogs were mainly infected by human-related MRSA isolates, i.e., clones usually reported in human infections, thus mirroring the human epidemiology in hospitals in France. Isolates belonging to the CC398 clone (SCCmec type IV or V were also identified in 21.4% of dogs’ and 26.5% of cats’ MRSA isolates. In order to differentiate human-related from CC398 MRSA, tetracycline-resistance [or tet(M detection] could be useful since this resistance is scarce in human-related strains but constant in CC398 MRSA isolates. In all, our data give a nationwide epidemiological picture of MRSA in companion animals over a 5-year period in France, adding further epidemiological information on the contribution of those animal species to a major public health issue. Considering the wide dissemination of CC398 MRSA isolates and the fact that 11/64 (17.2% of them presented the Immune Evasion Cluster which enhances CC398 capacities to colonize humans, a

Trends and molecular mechanisms of antimicrobial resistance in clinical staphylococci isolated from companion animals over a 16 year period.

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Couto, Natacha; Monchique, Cláudia; Belas, Adriana; Marques, Cátia; Gama, Luís T; Pomba, Constança

2016-06-01

The objective of this study was to investigate the evolution of resistance to antimicrobials, corresponding mechanisms and molecular characteristics of Staphylococcus spp., between 1999 and 2014. Susceptibility to 38 antimicrobials was determined for 632 clinical staphylococcal isolates obtained from companion animals (dogs, cats, horses and other animals). Twenty antimicrobial resistance genes, including mecA and mecC, were screened by PCR. Methicillin-resistant staphylococci were characterized by spa (Staphylococcus aureus), SCCmec, MLST and PFGE typing. Statistical analyses were performed using SAS v9.3 and differences were considered relevant if P ≤ 0.05. The mecA gene was identified in 74 staphylococcal isolates (11.6%): 11 MRSA (40.7%), 40 methicillin-resistant Staphylococcus pseudintermedius (MRSP; 8.7%) and 23 methicillin-resistant CoNS (26.7%). Resistance to the majority of antimicrobials and the number of mecA-positive isolates increased significantly over time. Eighteen spa types were identified, including two new ones. MRSA isolates were divided into three PFGE clusters that included ST22-IV, ST105-II, ST398-V and ST5-VI. Most methicillin-resistant Staphylococcus epidermidis isolates were of clonal complex (CC) 5, including a new ST, and clustered in eight PFGE clusters. MRSP were grouped into five PFGE clusters and included ST45-NT, ST71-II-III, ST195-III, ST196-V, ST339-NT, ST342-IV and the new ST400-III. Methicillin-resistant Staphylococcus haemolyticus clustered in two PFGE clusters. The significant increase in antimicrobial-resistant and mecA-positive isolates in recent years is worrying. Furthermore, several isolates are MDR, which complicates antimicrobial treatment and increases the risk of transfer to humans or human isolates. Several clonal lineages of MRSA and methicillin-resistant S. epidermidis circulating in human hospitals and the community were found, suggesting that companion animals can become infected with and contribute to the

Efeito do ultrassom terapêutico sobre as propriedades mecânicas do gastrocnêmio em ratos

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Hállamo Henrique Saraiva Barbosa

2014-04-01

Full Text Available INTRODUÇÃO: Apesar de algumas controvérsias quanto à sua utilização, o ultrassom terapêutico (UST é um recurso comumente aplicado na reabilitação desportiva para aceleração do reparo tecidual de lesões musculares. Sabe-se que lesões musculares influenciam negativamente as propriedades mecânicas da musculatura estriada esquelética e algumas evidências demonstram que o UST poderia ter efeitos benéficos sobre o reparo muscular e, consequentemente, sobre suas propriedades mecânicas. OBJETIVO: Analisar o efeito do UST no reparo tecidual por meio das propriedades mecânicas musculares de ratos após trauma por criolesão. MÉTODOS: Foram utilizados no estudo 30 ratos da linhagem Wistar, os quais foram divididos em três grupos: grupo controle intacto (GC, grupo lesionado sem tratamento (GL, e grupo lesionado e estimulado com UST (frequência de 1 MHz; intensidade de 0,5 W/cm2; ciclo de trabalho de 50%; por quatro minutos diários, durante sete dias consecutivos (GLUST. As propriedades mecânicas obtidas através de ensaio mecânico de tração foram avaliadas em uma máquina universal de ensaios. RESULTADOS: Foram analisados estatisticamente, com nível de significância de 95% (P<0,05. Após sete sessões de tratamento, houve melhora estatisticamente significativa nas propriedades mecânicas de carga no limite de proporcionalidade, carga no limite máximo e resiliência para o GLUST em relação ao GL (p<0,05. CONCLUSÃO: O UST foi eficaz no processo de reparo tecidual, conferindo ao tecido muscular maior resistência à tração e absorção de energia.

In vitro transfer of methicillin resistance determinants mecA from methicillin resistant Staphylococcus aureus (MRSA) to methicillin susceptible Staphylococcus aureus (MSSA).

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Bitrus, Asinamai Athliamai; Zunita, Zakaria; Bejo, Siti Khairani; Othman, Sarah; Nadzir, Nur Adilah Ahmad

2017-04-04

Staphylococcus aureus more than any other human pathogen is a better model for the study of the adaptive evolution of bacterial resistance to antibiotics, as it has demonstrated a remarkable ability in its response to new antibiotics. This study was designed to investigate the in vitro transfer of mecA gene from methicillin resistant S. aureus to methicillin susceptible S. aureus. The recipient transconjugants were resistant to erythromycin, cefpodoxime and were mecA positive. PCR amplification of mecA after mix culture plating on Luria Bertani agar containing 100 μg/mL showed that 75% of the donor and 58.3% of the recipient transconjugants were mecA positive. Additionally, 61.5% of both the donor cells and recipient transconjugants were mecA positive, while 46.2% and 41.75% of both donor and recipient transconjugants were mecA positive on LB agar containing 50 μg/mL and 30 μg/mL respectively. In this study, the direction of transfer of phenotypic resistance as well as mecA was observed to have occurred from the donor to the recipient strains. This study affirmed the importance of horizontal transfer events in the dissemination of antibiotics resistance among different strains of MRSA.

Distribution of mecA gene amongst Staphylococcus aureus isolates

African Journals Online (AJOL)

Dr Olaleye

Antibiotics susceptibility testing including methicillin sensitivity testing, beta lactamase testing, PCR for detection of mecA gene, and minimum inhibitory concentrations to methicillin were carried out on all the 194 isolates of S. aureus. Among the 194 strains, 40 (20.6%) were MRSA using 10 µg methicillin disc. PCR analysis.

Multiplex Real-Time PCR for Detection of Staphylococcus aureus, mecA and Panton-Valentine Leukocidin (PVL) Genes from Selective Enrichments from Animals and Retail Meat

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Velasco, Valeria; Sherwood, Julie S.; Rojas-García, Pedro P.; Logue, Catherine M.

2014-01-01

The aim of this study was to compare a real-time PCR assay, with a conventional culture/PCR method, to detect S. aureus, mecA and Panton-Valentine Leukocidin (PVL) genes in animals and retail meat, using a two-step selective enrichment protocol. A total of 234 samples were examined (77 animal nasal swabs, 112 retail raw meat, and 45 deli meat). The multiplex real-time PCR targeted the genes: nuc (identification of S. aureus), mecA (associated with methicillin resistance) and PVL (virulence factor), and the primary and secondary enrichment samples were assessed. The conventional culture/PCR method included the two-step selective enrichment, selective plating, biochemical testing, and multiplex PCR for confirmation. The conventional culture/PCR method recovered 95/234 positive S. aureus samples. Application of real-time PCR on samples following primary and secondary enrichment detected S. aureus in 111/234 and 120/234 samples respectively. For detection of S. aureus, the kappa statistic was 0.68–0.88 (from substantial to almost perfect agreement) and 0.29–0.77 (from fair to substantial agreement) for primary and secondary enrichments, using real-time PCR. For detection of mecA gene, the kappa statistic was 0–0.49 (from no agreement beyond that expected by chance to moderate agreement) for primary and secondary enrichment samples. Two pork samples were mecA gene positive by all methods. The real-time PCR assay detected the mecA gene in samples that were negative for S. aureus, but positive for Staphylococcus spp. The PVL gene was not detected in any sample by the conventional culture/PCR method or the real-time PCR assay. Among S. aureus isolated by conventional culture/PCR method, the sequence type ST398, and multi-drug resistant strains were found in animals and raw meat samples. The real-time PCR assay may be recommended as a rapid method for detection of S. aureus and the mecA gene, with further confirmation of methicillin-resistant S. aureus (MRSA) using

Multiplex real-time PCR for detection of Staphylococcus aureus, mecA and Panton-Valentine Leukocidin (PVL genes from selective enrichments from animals and retail meat.

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Valeria Velasco

Full Text Available The aim of this study was to compare a real-time PCR assay, with a conventional culture/PCR method, to detect S. aureus, mecA and Panton-Valentine Leukocidin (PVL genes in animals and retail meat, using a two-step selective enrichment protocol. A total of 234 samples were examined (77 animal nasal swabs, 112 retail raw meat, and 45 deli meat. The multiplex real-time PCR targeted the genes: nuc (identification of S. aureus, mecA (associated with methicillin resistance and PVL (virulence factor, and the primary and secondary enrichment samples were assessed. The conventional culture/PCR method included the two-step selective enrichment, selective plating, biochemical testing, and multiplex PCR for confirmation. The conventional culture/PCR method recovered 95/234 positive S. aureus samples. Application of real-time PCR on samples following primary and secondary enrichment detected S. aureus in 111/234 and 120/234 samples respectively. For detection of S. aureus, the kappa statistic was 0.68-0.88 (from substantial to almost perfect agreement and 0.29-0.77 (from fair to substantial agreement for primary and secondary enrichments, using real-time PCR. For detection of mecA gene, the kappa statistic was 0-0.49 (from no agreement beyond that expected by chance to moderate agreement for primary and secondary enrichment samples. Two pork samples were mecA gene positive by all methods. The real-time PCR assay detected the mecA gene in samples that were negative for S. aureus, but positive for Staphylococcus spp. The PVL gene was not detected in any sample by the conventional culture/PCR method or the real-time PCR assay. Among S. aureus isolated by conventional culture/PCR method, the sequence type ST398, and multi-drug resistant strains were found in animals and raw meat samples. The real-time PCR assay may be recommended as a rapid method for detection of S. aureus and the mecA gene, with further confirmation of methicillin-resistant S. aureus (MRSA

Community-acquired necrotizing pneumonia caused by methicillin-resistant Staphylococcus aureus ST30-SCCmecIVc-spat019-PVL positive in San Antonio de Areco, Argentina.

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Fernandez, Silvina; Murzicato, Sofía; Sandoval, Orlando; Fernández-Canigia, Liliana; Mollerach, Marta

2015-01-01

Community-acquired methicillin-resistant Staphylococcus aureus is the first cause of skin and soft tissue infections, but can also produce severe diseases such as bacteremia, osteomyelitis and necrotizing pneumonia. Some S. aureus lineages have been described in cases of necrotizing pneumonia worldwide, usually in young, previously healthy patients. In this work, we describe a fatal case of necrotizing pneumonia due to community-acquired methicillin-resistant S. aureus clone ST30-SCCmecIVc-spat019-PVL positive in an immunocompetent adult patient. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Nasal carriage of mecA-positive methicillin-resistant Staphylococcus aureus in pigs exhibits dose-response to zinc supplementation.

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Amachawadi, Raghavendra G; Scott, Harvey M; Nitikanchana, Sureemas; Vinasco, Javier; Tokach, Mike D; Dritz, Steve S; Nelssen, Jim L; Goodband, Robert D; Nagaraja, Tiruvoor G

2015-02-01

Zinc (Zn) is often supplemented at elevated concentrations in swine diets, particularly in piglets, to prevent enteric infections and promote growth. Previous studies from Denmark have suggested a genetic linkage and a phenotypic association between Zn resistance, encoded by czrC, and methicillin-resistance conferred by mecA in Staphylococcus aureus. Such an association has not been reported in the U.S. swine population. We conducted an analysis of the effects of Zn, supplemented as zinc oxide (ZnO), on the nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) in nursery (n=40) and finisher pigs (n=40) enrolled in a nutritional study. Nasal swabs, collected from nursery and finisher pigs, were inoculated onto MRSA CHROMagar and presumptive MRSA colonies were tested for the presence of mecA and czrC genes by polymerase chain reaction. Zinc susceptibility was determined by the agar dilution method. The prevalence of mecA-positive MRSA was 10% (4/40) and 20% (8/40) among nursery and finisher pigs, respectively. Of the 12 mecA-positive S. aureus isolates, 7 had the czrC gene (58.3%) compared to none among the 68 mecA-negative isolates. The presence of both mecA (p=0.002) and czrC (p=0.006) genes were positively associated with higher levels of Zn supplementation. The median minimum inhibitory concentrations of Zn for czrC-positive and czrC-negative isolates were 12 and 2 mM, respectively (presistance among S. aureus in pigs.

Presence, distribution, and molecular epidemiology of methicillin-resistant Staphylococcus aureus in a small animal teaching hospital: a year-long active surveillance targeting dogs and their environment.

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van Balen, Joany; Kelley, Christina; Nava-Hoet, Rocio C; Bateman, Shane; Hillier, Andrew; Dyce, Jonathan; Wittum, Thomas E; Hoet, Armando E

2013-05-01

Methicillin-resistant Staphylococcus aureus (MRSA) is known to be present in small animal veterinary clinical environments. However, a better understanding of the ecology and dynamics of MRSA in these environments is necessary for the development of effective infectious disease prevention and control programs. To achieve this goal, a yearlong active MRSA surveillance program was established at The Ohio State University (OSU) Veterinary Medical Center to describe the spatial and molecular epidemiology of this bacterium in the small animal hospital. Antimicrobial susceptibility testing, staphylococcal chromosomal cassette mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE) typing, and dendrogram analysis were used to characterize and analyze the 81 environmental and 37 canine-origin MRSA isolates obtained during monthly sampling events. Overall, 13.5% of surfaces were contaminated with MRSA at 1 or more sampling times throughout the year. The majority of the environmental and canine isolates were SCCmec type II (93.8% and 86.5%, respectively) and USA100 (90.1% and 86.5%, respectively). By PFGE analysis, these isolates were found to be closely related, which reflects a low diversity of MRSA strains circulating in the hospital. For 5 consecutive months, 1 unique pulsotype was the most prevalent across the medical services and was recovered from a variety of surfaces and hospital locations. Carts/gurneys, doors, and examination tables/floors were the most frequently contaminated surfaces. Some surfaces maintained the same pulsotypes for 3 consecutive months. Molecular analysis found that incoming MRSA-positive dogs were capable of introducing a new pulsotype into the hospital environment during the surveillance period. Our results suggest that once a MRSA strain is introduced into the hospital environment, it can be maintained and spread for extended periods of time. These findings can aid in the development of biosecurity and biocontainment protocols aimed at

Community-acquired methicillin-resistant Staphylococcus aureus: community transmission, pathogenesis, and drug resistance.

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Yamamoto, Tatsuo; Nishiyama, Akihito; Takano, Tomomi; Yabe, Shizuka; Higuchi, Wataru; Razvina, Olga; Shi, Da

2010-08-01

Methicillin-resistant Staphylococcus aureus (MRSA) is able to persist not only in hospitals (with a high level of antimicrobial agent use) but also in the community (with a low level of antimicrobial agent use). The former is called hospital-acquired MRSA (HA-MRSA) and the latter community-acquired MRSA (CA-MRSA). It is believed MRSA clones are generated from S. aureus through insertion of the staphylococcal cassette chromosome mec (SCCmec), and outbreaks occur as they spread. Several worldwide and regional clones have been identified, and their epidemiological, clinical, and genetic characteristics have been described. CA-MRSA is likely able to survive in the community because of suitable SCCmec types (type IV or V), a clone-specific colonization/infection nature, toxin profiles (including Pantone-Valentine leucocidin, PVL), and narrow drug resistance patterns. CA-MRSA infections are generally seen in healthy children or young athletes, with unexpected cases of diseases, and also in elderly inpatients, occasionally surprising clinicians used to HA-MRSA infections. CA-MRSA spreads within families and close-contact groups or even through public transport, demonstrating transmission cores. Re-infection (including multifocal infection) frequently occurs, if the cores are not sought out and properly eradicated. Recently, attention has been given to CA-MRSA (USA300), which originated in the US, and is growing as HA-MRSA and also as a worldwide clone. CA-MRSA infection in influenza season has increasingly been noted as well. MRSA is also found in farm and companion animals, and has occasionally transferred to humans. As such, the epidemiological, clinical, and genetic behavior of CA-MRSA, a growing threat, is focused on in this study.

Detection of oxacillin-susceptible mecA-positive Staphylococcus aureus isolates by use of chromogenic medium MRSA ID.

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Kumar, V Anil; Steffy, Katherin; Chatterjee, Maitrayee; Sugumar, Madhan; Dinesh, Kavitha R; Manoharan, Anand; Karim, Shamsul; Biswas, Raja

2013-01-01

Reports of oxacillin-susceptible mecA-positive Staphylococcus aureus strains are on the rise. Because of their susceptibility to oxacillin and cefoxitin, it is very difficult to detect them by using routine phenotypic methods. We describe two such isolates that were detected by chromogenic medium and confirmed by characterization of the mecA gene element.

Recomendações brasileiras de ventilação mecânica 2013. Parte I

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Carmen Sílvia Valente Barbas

2014-04-01

Full Text Available O suporte ventilatório artificial invasivo e não invasivo ao paciente crítico tem evoluído e inúmeras evidências têm surgido, podendo ter impacto na melhora da sobrevida e da qualidade do atendimento oferecido nas unidades de terapia intensiva no Brasil. Isto posto, a Associação de Medicina Intensiva Brasileira (AMIB e a Sociedade Brasileira de Pneumologia e Tisiologia (SBPT - representadas pelo seus Comitê de Ventilação Mecânica e Comissão de Terapia Intensiva, respectivamente, decidiram revisar a literatura e preparar recomendações sobre ventilação mecânica objetivando oferecer aos associados um documento orientador das melhores práticas da ventilação mecânica na beira do leito, baseado nas evidencias existentes, sobre os 29 subtemas selecionados como mais relevantes no assunto. O projeto envolveu etapas visando distribuir os subtemas relevantes ao assunto entre experts indicados por ambas as sociedades que tivessem publicações recentes no assunto e/ou atividades relevantes em ensino e pesquisa no Brasil na área de ventilação mecânica. Esses profissionais, divididos por subtemas em duplas, responsabilizaram-se por fazer revisão extensa da literatura mundial sobre cada subtema. Reuniram-se todos no Forum de Ventilação Mecânica na sede da AMIB em São Paulo, em 03 e 04 de agosto de 2013 para finalização conjunta do texto de cada subtema e apresentação, apreciação, discussão e aprovação em plenária pelos 58 participantes, permitindo a elaboração de um documento final.

Complicaciones mecánicas del infarto agudo de miocardio: aunque infrecuentes, potencialmente letales

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Jerson Quitian Moreno

2017-09-01

Full Text Available Aunque la incidencia de complicaciones mecánicas en el infarto agudo de miocardio ha descendido después de la era de la intervención coronaria percutánea, la mortalidad sigue siendo significativa. La ruptura septal ventricular, la regurgitación mitral aguda y la ruptura de la pared libre del ventrículo izquierdo conforman el espectro de complicaciones mecánicas posteriores al infarto agudo de miocardio. La reparación quirúrgica es el pilar del tratamiento; sin embargo, como puente para la cirugía, el manejo médico permite estabilizar al paciente.

Retrospective study of necrotizing fasciitis and characterization of its associated Methicillin-resistant Staphylococcus aureus in Taiwan

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Changchien Chih-Hsuan

2011-10-01

Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA has emerged as a prevalent pathogen of necrotizing fasciitis (NF in Taiwan. A four-year NF cases and clinical and genetic differences between hospital acquired (HA- and community-acquired (CA-MRSA infection and isolates were investigated. Methods A retrospective study of 247 NF cases in 2004-2008 and antimicrobial susceptibilities, staphylococcal chromosomal cassette mec (SCCmec types, pulsed field gel electrophoresis (PFGE patterns, virulence factors, and multilocus sequence typing (MLST of 16 NF-associated MRSA in 2008 were also evaluated. Results In 247 cases, 42 microbial species were identified. S. aureus was the major prevalent pathogen and MRSA accounted for 19.8% of NF cases. Most patients had many coexisting medical conditions, including diabetes mellitus, followed by hypertension, chronic azotemia and chronic hepatic disease in order of decreasing prevalence. Patients with MRSA infection tended to have more severe clinical outcomes in terms of amputation rate (p S. aureus or non-S. aureus infection. NF patients infected by HA-MRSA had a significantly higher amputation rate, comorbidity, C-reactive protein level, and involvement of lower extremity than those infected by CA-MRSA. In addition to over 90% of MRSA resistant to erythromycin and clindamycin, HA-MRSA was more resistant than CA-MRSA to trimethoprim-sulfamethoxazole (45.8% vs. 4%. ST59/pulsotype C/SCCmec IV and ST239/pulsotype A/SCCmec III isolates were the most prevalent CA- and HA-MRSA, respectively in 16 isolates obtained in 2008. In contrast to the gene for γ-hemolysin found in all MRSA, the gene for Panton-Valentine leukocidin was only identified in ST59 MRSA isolates. Other three virulence factors TSST-1, ETA, and ETB were occasionally identified in MRSA isolates tested. Conclusion NF patients with MRSA infection, especially HA-MRSA infection, had more severe clinical outcomes than those infected by

Livestock-Associated Methicillin Resistant and Methicillin Susceptible Staphylococcus aureus Sequence Type (CC1 in European Farmed Animals: High Genetic Relatedness of Isolates from Italian Cattle Herds and Humans.

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Patricia Alba

Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA Sequence Type (ST1, Clonal Complex(CC1, SCCmec V is one of the major Livestock-Associated (LA- lineages in pig farming industry in Italy and is associated with pigs in other European countries. Recently, it has been increasingly detected in Italian dairy cattle herds. The aim of this study was to analyse the differences between ST1 MRSA and methicillin-susceptible S. aureus (MSSA from cattle and pig herds in Italy and Europe and human isolates. Sixty-tree animal isolates from different holdings and 20 human isolates were characterized by pulsed-field gel electrophoresis (PFGE, spa-typing, SCCmec typing, and by micro-array analysis for several virulence, antimicrobial resistance, and strain/host-specific marker genes. Three major PFGE clusters were detected. The bovine isolates shared a high (≥90% to 100% similarity with human isolates and carried the same SCCmec type IVa. They often showed genetic features typical of human adaptation or present in human-associated CC1: Immune evasion cluster (IEC genes sak and scn, or sea; sat and aphA3-mediated aminoglycoside resistance. Contrary, typical markers of porcine origin in Italy and Spain, like erm(A mediated macrolide-lincosamide-streptograminB, and of vga(A-mediated pleuromutilin resistance were always absent in human and bovine isolates. Most of ST(CC1 MRSA from dairy cattle were multidrug-resistant and contained virulence and immunomodulatory genes associated with full capability of colonizing humans. As such, these strains may represent a greater human hazard than the porcine strains. The zoonotic capacity of CC1 LA-MRSA from livestock must be taken seriously and measures should be implemented at farm-level to prevent spill-over.

Livestock-Associated Methicillin Resistant and Methicillin Susceptible Staphylococcus aureus Sequence Type (CC)1 in European Farmed Animals: High Genetic Relatedness of Isolates from Italian Cattle Herds and Humans.

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Alba, Patricia; Feltrin, Fabiola; Cordaro, Gessica; Porrero, María Concepción; Kraushaar, Britta; Argudín, María Angeles; Nykäsenoja, Suvi; Monaco, Monica; Stegger, Marc; Aarestrup, Frank M; Butaye, Patrick; Franco, Alessia; Battisti, Antonio

2015-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) Sequence Type (ST)1, Clonal Complex(CC)1, SCCmec V is one of the major Livestock-Associated (LA-) lineages in pig farming industry in Italy and is associated with pigs in other European countries. Recently, it has been increasingly detected in Italian dairy cattle herds. The aim of this study was to analyse the differences between ST1 MRSA and methicillin-susceptible S. aureus (MSSA) from cattle and pig herds in Italy and Europe and human isolates. Sixty-tree animal isolates from different holdings and 20 human isolates were characterized by pulsed-field gel electrophoresis (PFGE), spa-typing, SCCmec typing, and by micro-array analysis for several virulence, antimicrobial resistance, and strain/host-specific marker genes. Three major PFGE clusters were detected. The bovine isolates shared a high (≥90% to 100%) similarity with human isolates and carried the same SCCmec type IVa. They often showed genetic features typical of human adaptation or present in human-associated CC1: Immune evasion cluster (IEC) genes sak and scn, or sea; sat and aphA3-mediated aminoglycoside resistance. Contrary, typical markers of porcine origin in Italy and Spain, like erm(A) mediated macrolide-lincosamide-streptograminB, and of vga(A)-mediated pleuromutilin resistance were always absent in human and bovine isolates. Most of ST(CC)1 MRSA from dairy cattle were multidrug-resistant and contained virulence and immunomodulatory genes associated with full capability of colonizing humans. As such, these strains may represent a greater human hazard than the porcine strains. The zoonotic capacity of CC1 LA-MRSA from livestock must be taken seriously and measures should be implemented at farm-level to prevent spill-over.

Public health officials and MECs for health should be held criminally ...

African Journals Online (AJOL)

2017-12-01

Dec 1, 2017 ... MEC and his colleagues award the same company a service contract ... the intention to kill; (ii) the person's act or omission was unlawful; ..... Director of Public Prosecution Gauteng v Pistorius 2016(1) SACR 431 (SCA). 6.

Structural variations of staphylococcal cassette chromosome mec Type IVa in Staphylococcus aureus clonal complex 8 and unrelated lineages

DEFF Research Database (Denmark)

Damborg, Peter Panduro; Bartels, Mette Damkjær; Boye, Kit

2011-01-01

PCR mapping of staphylococcal cassette chromosome mec type IVa and adjacent mobile elements in 94 methicillin-resistant Staphylococcus aureus (MRSA) strains identified two primary structures (A and B) that could be further classified into two (A1 and A2) and five (B1 to B5) variants, primarily...... based on structural differences in the orfX-J3 region. While spa type t008 (USA300) invariably contained the A variants, other spa types belonging to clonal complex 8 and unrelated lineages generally contained B variants. These findings have important implications for the typing and identification...

Qualidade de maçãs 'Fuji Suprema' submetidas a diferentes tipos de dano mecânico

Directory of Open Access Journals (Sweden)

Marcos Vinicius Hendges

2011-06-01

Full Text Available Objetivo deste trabalho foi avaliar o efeito do dano mecânico por impacto, compressão e corte sobre a qualidade de maçãs 'Fuji Suprema' mantidas em condição ambiente. Os tratamentos avaliados foram: controle (sem dano mecânico, dano mecânico por impacto, dano mecânico por compressão e dano mecânico por corte. Os diferentes danos não influenciaram na firmeza de polpa e no ângulo 'hue' da casca. O dano por corte proporcionou frutos com menor acidez titulável, nove dias após a aplicação do dano. Frutos submetidos ao dano por impacto apresentaram maior teor de sólidos solúveis, quinze dias após a aplicação dos danos. Os danos por impacto e corte causaram o menor valor de L da polpa em todas as avaliações, evidenciando o escurecimento da polpa. Contudo, este efeito não foi observado na epiderme. Todos os frutos danificados por corteapresentaram podridão após nove dias da aplicação dos danos.De maneira geral, pode-se concluir que, nas intensidades testadas, maçãs 'Fuji Suprema' submetidas ao dano por impacto e corte apresentam prejuízos em sua qualidade, pois ocorre escurecimento da polpa no local do dano. Além disso, o dano por corte reduz a vida pós-colheita dos frutos, facilitando a ocorrência de podridões.

Caracterización de propiedades físico-mecánicas de rocas ígneas utilizadas en obras de infraestructura

OpenAIRE

M. Navarrete

2013-01-01

Los materiales pétreos se emplean actualmente en casi todos los procesos edificatorios y debido a esto se les realizan diferentes pruebas, pudiendo ser tanto físicas como mecánicas; en éstas, el ensayo de carga puntual normado por ASTM D 5731, describe el empleo del equipo Point Load para determinar la resistencia mecánica en rocas no labradas, con tamaño aproximado de 4 pulgadas de diámetro, determinándose características mecánicas con alta confiabilidad y facilidad...

Trombolisis farmacológica y mecánica en tromboembolismo pulmonar submasivo

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Jorge O. Cáneva

2014-04-01

Full Text Available La enfermedad tromboembólica pulmonar, en sus formas aguda, subaguda o crónica, presenta dificultades para su tratamiento y tiene elevada morbimortalidad. La gravedad del evento agudo y su potencial compromiso sobre la función del ventrículo derecho necesitan estrategias terapéuticas, a veces combinadas, para cambiar el curso de la enfermedad a favor de la supervivencia del paciente. Las trombolisis farmacológica y mecánica son instrumentos útiles para tratar un evento embólico pulmonar agudo grave. Se presenta el caso de una joven que desarrolló una embolia pulmonar submasiva de instalación subaguda en quien la terapia combinada y secuencial trombolítica, farmacológica y mecánica, fue exitosa.

Asistencia respiratoria mecánica: Influencia de la edad en la evolución

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Felipe J. Chertcoff

2011-02-01

Full Text Available No existe un concepto definido sobre la influencia de la edad en la mortalidad de la asistencia respiratoria mecánica. Realizamos un trabajo prospectivo-observacional para determinar si la edad es un factor independiente de mortalidad de la asistencia respiratoria mecánica. Se incluyeron 200 pacientes internados en la Unidad de Cuidados Intensivos del Hospital Británico de Buenos Aires. Se registraron características y comorbilidades al ingreso, al inicio de la asistencia respiratoria mecánica, complicaciones y evolución en el Hospital y a los 6 meses. Los 200 pacientes incluidos fueron divididos en dos grupos: Grupo 1 (n = 164 menores de 80 años y Grupo 2 (n = 36 de 80 años o más. No hubo diferencias en la mortalidad en la Unidad de Cuidados Intensivos y en el Hospital entre los pacientes menores de 80 años y los de 80 años o más. (55.56% vs. 41.46% y 58.33% vs. 42.68%. La supervivencia a los 6 meses de los = 80 años fue significativamente menor (22.22% vs. 48.17%, p = 0.0051. En el análisis multivariado solamente un APACHE II > 20 (p = 0.0007 o la ausencia de vida autónoma (p = 0.0028 conservaron poder predictivo independiente. Los pacientes añosos que reciben asistencia respiratoria mecánica no presentan una mayor mortalidad por el sólo hecho de ser ancianos. La restricción de los cuidados terapéuticos invasivos no parece justificada por la edad avanzada.

Molecular and clinical characteristics of clonal complex 59 methicillin-resistant Staphylococcus aureus infections in Mainland China.

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Juan Li

Full Text Available Detailed molecular analyses of Clonal Complex 59 (CC59 methicillin-resistant Staphylococcus aureus (MRSA isolates from children in seven major cities across Mainland China were examined. A total of 110 CC59 isolates from invasive and non-invasive diseases were analyzed by multilocus sequence typing (MLST, Staphylococcus cassette chromosome mec (SCCmec typing, staphylococcal protein A (spa typing and pulsed-field gel electrophoresis (PFGE. Antibiotics susceptibilities, carriage of plasmids and 42 virulence genes and the expression of virulence factors were examined. ST59 (101/110, 91.8% was the predominant sequence type (ST, while single locus variants (SLVs belonging to ST338 (8/110, 7.3% and ST375 (1/110, 0.9% were obtained. Three SCCmec types were found, namely type III (2.7%, type IV (74.5% and type V (22.7%. Seven spa types including t437, which accounted for 87.3%, were determined. Thirteen PFGE types were obtained. PFGE types A and B were the major types totally accounting for 81.8%. The dominant clone was ST59-t437-IVa (65.5%, followed by ST59-t437-V (14.5%. The positive rate of luks-PV and lukF-PV PVL encoding (pvl gene was 55.5%. Plasmids were detected in 83.6% (92/110 of the strains. The plasmid size ranging from 23.4 kb to 50 kb was most prevalent which accounted for 83.7% (77/92. A significantly lower expression of hla was found in ST59-t437-IVa compared with ST59-t437-V. Among the 110 cases, 61.8% of the patients were less than 1 year old. A total of 90 cases (81.8% were community-associated (CA infections whereas 20 cases (18.2% were hospital-associated (HA infections. Out of the 110 patients, 36.4% (40/110 were diagnosed with invasive infectious diseases in which ST59-t437-IVa accounted for 67.5% (27/40. In brief, ST59-t437-IVa was proved as the dominant clone in CC59 MRSA strains. The carriage rate of pvl gene was high. CC59 MRSA could result in CA and HA infections. The majortiy of MRSA infection children were in young age.

MRSA Causing Infections in Hospitals in Greater Metropolitan New York: Major Shift in the Dominant Clonal Type between 1996 and 2014.

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Maria Pardos de la Gandara

Full Text Available A surveillance study in 1996 identified the USA100 clone (ST5/SCCmecII-also known as the "New York/Japan" clone-as the most prevalent MRSA causing infections in 12 New York City hospitals. Here we update the epidemiology of MRSA in seven of the same hospitals eighteen years later in 2013/14. Most of the current MRSA isolates (78 of 121 belonged to the MRSA clone USA300 (CC8/SCCmecIV but the USA100 clone-dominant in the 1996 survey-still remained the second most frequent MRSA (25 of the 121 isolates causing 32% of blood stream infections. The USA300 clone was most common in skin and soft tissue infections (SSTIs and was associated with 84.5% of SSTIs compared to 5% caused by the USA100 clone. Our data indicate that by 2013/14, the USA300 clone replaced the New York/Japan clone as the most frequent cause of MRSA infections in hospitals in Metropolitan New York. In parallel with this shift in the clonal type of MRSA, there was also a striking change in the types of MRSA infections from 1996 to 2014.

Characterisation of MRSA from Malta and the description of a Maltese epidemic MRSA strain.

LENUS (Irish Health Repository)

Scicluna, E A

2010-02-01

Malta has one of the highest prevalence rates of methicillin-resistant Staphylococcus aureus (MRSA) in Europe. However, only limited typing data are currently available. In order to address this situation, 45 MRSA isolates from the Mater Dei Hospital in Msida, Malta, were characterised using DNA microarrays. The most common strain was ST22-MRSA-IV (UK-EMRSA-15, 30 isolates). Sporadic strains included ST36-MRSA-II (UK-EMRSA-16, two isolates), PVL-positive ST80-MRSA-IV (European Clone, one isolate), ST228-MRSA-I (Italian Clone\\/South German Epidemic Strain, one isolate) and ST239-MRSA-III (Vienna\\/Hungarian\\/Brazilian Epidemic Strain, one isolate). Ten MRSA isolates belonged to a clonal complex (CC) 5\\/ST149, spa type t002 strain. This strain harboured an SCCmec IV element (mecA, delta mecR, ugpQ, dcs, ccrA2 and ccrB2), as well as novel alleles of ccrA\\/B and the fusidic acid resistance element Q6GD50 (previously described in the sequenced strain MSSA476, BX571857.1:SAS0043). It also carried the gene for enterotoxin A (sea) and the egc enterotoxin locus, as well as (in nine out of ten isolates) genes encoding the toxic shock syndrome toxin (tst1) and enterotoxins C and L (sec, sel). While the presence of the other MRSA strains suggests foreign importation due to travel between Malta and other European countries, the CC5\\/t002 strain appears, so far, to be restricted to Malta.

Carriage of methicillin-resistant Staphylococcus pseudintermedius in small animal veterinarians

DEFF Research Database (Denmark)

Paul, Narayan Chandra; Moodley, Arshnee; Ghibaudo, G.

2011-01-01

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is increasingly reported in small animals and cases of human infections have already been described despite its recent emergence in veterinary practice. We investigated the prevalence of MRSP and methicillin-resistant Staphylococcus...... aureus (MRSA) among small animal dermatologists attending a national veterinary conference in Italy. Nasal swabs were obtained from 128 veterinarians, seven of which harboured MRSP (n = 5; 3.9%) or MRSA (n = 2; 1.6%). A follow-up study of two carriers revealed that MRSP persisted for at least 1 month...... by spa typing. Methicillin-resistant isolates were further typed by antimicrobial susceptibility testing, SCCmec and multi-locus sequence typing. Two lineages previously associated with pets were identified among the five MRSP isolates; the European epidemic clone ST71-SCCmec II-III and ST106-SCCmec IV...

Dredging in Sediments Containing Munitions and Explosives of Concern (MEC)

Science.gov (United States)

2008-08-01

UXO diver tech- niques to recover the targets. First, the diver using a fluxgate magnetometer attempted to verify the exist- ence of a target...MEC. These technologies included: 1. Synthetic Aperture SONAR. 2. Magnetometers and electromagnetic induction sensors. 3. Magnetometer /SONAR...4. Differential Magnetometer . 5. Mobile Underwater Debris Survey System. The feasibility of site characterization of the borrow area

Disentangling the Role of the MEC and LEC in the Processing of Spatial and Non-Spatial Information: Contribution of Lesion Studies

Directory of Open Access Journals (Sweden)

Etienne Save

2017-10-01

Full Text Available It is now widely accepted that the entorhinal cortex (EC plays a pivotal role in the processing of spatial information and episodic memory. The EC is segregated into two sub-regions, the medial EC (MEC and the lateral EC (LEC but a comprehensive understanding of their roles across multiple behavioral contexts remains unclear. Considering that it is still useful to investigate the impact of lesions of EC on behavior, we review the contribution of lesion approach to our knowledge of EC functions. We show that the MEC and LEC play different roles in the processing of spatial and non-spatial information. The MEC is necessary to the use of distal but not proximal landmarks during navigation and is crucial for path integration, in particular integration of linear movements. Consistent with predominant hypothesis, the LEC is important for combining the spatial and non-spatial aspects of the environment. However, object exploration studies suggest that the functional segregation between the MEC and the LEC is not as clearly delineated and is dependent on environmental and behavioral factors. Manipulation of environmental complexity and therefore of cognitive demand shows that the MEC and the LEC are not strictly necessary to the processing of spatial and non-spatial information. In addition we suggest that the involvement of these sub-regions can depend on the kind of behavior, i.e., navigation or exploration, exhibited by the animals. Thus, the MEC and the LEC work in a flexible manner to integrate the “what” and “where” information in episodic memory upstream the hippocampus.

Criterios de extubación ampliados en ventilación mecánica prolongada

OpenAIRE

Benveniste Pérez, Eva

2016-01-01

Tot i l'experiència acumulada durant dècades en l'ús de la Ventilació Mecànica Invasiva (VMI), al voltant d'un 20-25% dels pacients pateixen fracàs d'extubació. Aquest fenòmen comporta un augment de la durada de la ventilació mecànica, de l'estada a la UCI i hospitalària i de la mortalitat. Els pacients sotmesos a VMI de forma prolongada (VMP) i els pacients neurològics tenen més probabilitats de patir fracàs d'extubació. Ens hem proposat esbrinar quins són els factors de risc de fracàs d'ext...

An Efficient Offloading Scheme For MEC System Considering Delay and Energy Consumption

Science.gov (United States)

Sun, Yanhua; Hao, Zhe; Zhang, Yanhua

2018-01-01

With the increasing numbers of mobile devices, mobile edge computing (MEC) which provides cloud computing capabilities proximate to mobile devices in 5G networks has been envisioned as a promising paradigm to enhance users experience. In this paper, we investigate a joint consideration of delay and energy consumption offloading scheme (JCDE) for MEC system in 5G heterogeneous networks. An optimization is formulated to minimize the delay as well as energy consumption of the offloading system, which the delay and energy consumption of transmitting and calculating tasks are taken into account. We adopt an iterative greedy algorithm to solve the optimization problem. Furthermore, simulations were carried out to validate the utility and effectiveness of our proposed scheme. The effect of parameter variations on the system is analysed as well. Numerical results demonstrate delay and energy efficiency promotion of our proposed scheme compared with another paper’s scheme.

Realización de un protocolo en el proceso de destete en pacientes sometidos a ventilación mecánica asistida

OpenAIRE

Amo Simón, Sofía del

2015-01-01

El presente Trabajo de Fin de Grado (TFG) sobre el establecimiento de un protocolo para el destete de los pacientes sometidos a ventilación mecánica invasiva consta de una introducción y un desarrollo acerca del tema de la ventilación mecánica invasiva y el proceso de retirada progresiva de la misma, también conocido como destete o “weaning”, para establecer el protocolo, objetivo final de este trabajo. La ventilación mecánica invasiva es uno de los procedimientos más emplea...

Análisis del comportamiento mecánico de una aleación Ni-Cr-Mo para pilares dentales/Analysis of Mechanical Behavior of Ni-Cr-Mo alloy for Dental Abutments

Directory of Open Access Journals (Sweden)

Luis Alberto Laguado Villamizar

2012-12-01

Full Text Available El presente estudio caracteriza una aleación aplicable al diseño de pilares para implantes dentales. Se propone un material biocompatible y de alta resistencia mecánica como alternativa a las aleaciones de Titanio, disminuyendo los costos de materia prima y procesamiento. Se realizan pruebas mecánicas de tracción y de compresión a la aleación de Ni-Cr-Mo, posteriormente se realiza modelado 3D y simulación de sus propiedades mecánicas por medio de análisis de elementos finitos. Como resultado se obtiene que el material disminuye su resistencia mecánica después del proceso de fundición empleado. El modelo de simulación es válido para análisis de resistencia en pilares dentales.This study presents the characterization of a dental implant alloy for abutments. It proposes a biocompatible material and high mechanical resistance as an alternative to Titanium alloys, lowering costs of raw materials and processing. Mechanical testing of the Ni-Cr-Mo alloy and subsequently perform simulations of its mechanical properties by means of finite element analysis. As a result is obtained that the material reduces its mechanical strength after the casting for electric induction molding process. The simulation model is valid to make analysis of resistance to this type of dental devices.

Propiedades mecánicas del acero de refuerzo utilizado en Colombia Propiedades mecánicas del acero de refuerzo utilizado en Colombia

OpenAIRE

Victoria González Quintana; Juan Carlos Botero; Roberto Rochel; Julián Vidal; Martha Cecilia Alvarez Uribe

2005-01-01

Se presentan resultados del análisis estadístico aplicado al estudio experimental que de- termina las propiedades mecánicas de aceros colombianos sometidos a cargas monotónicas de tracción. Se obtienen curvas típicas de esfuerzo-deformación que permiten caracterizar aceros nacionales estudiados haciendo énfasis en las variables que determinan el cambio de comportamiento del materialA statistical analysis applied to a experimental study that determines the mechanical properties of steels produ...

Avaliação das propriedades mecânicas de atadura gessada de três diferentes fabricantes, utilizada para confecção de órteses

OpenAIRE

Vieira,Gustavo Cardoso; Fonseca,Marisa de Cássia Registro; Shimano,Antônio Carlos; Mazzer,Nilton; Barbieri,Cláudio Henrique; Elui,Valéria Carril Meirelles

2006-01-01

Foram realizados testes mecânicos com atadura gessada de três diferentes fabricantes, utilizada para confecção de órteses. Para isso, foram confeccionados corpos de provas (CDPs) na forma de placas e de cilindros. Os CDPs foram submetidos a dois tipos de ensaios mecânicos: para o grupo das placas foi realizado ensaio de flexão em três pontos e para o grupo dos cilindros, ensaio de compressão. Os ensaios mecânicos foram realizados na Máquina Universal de Ensaios EMIC®. Três propriedades mecâni...

Identification of Variable Traits among the Methicillin Resistant and Sensitive Coagulase Negative Staphylococci in Milk Samples from Mastitic Cows in India

Directory of Open Access Journals (Sweden)

Sudipta Mahato

2017-07-01

Full Text Available Methicillin resistant Staphylococcus aureus causing bovine mastitis has been very well investigated worldwide. However, there are only limited reports on the characterization of methicillin resistant and sensitive coagulase negative staphylococci (CoNS across the globe. Hence, in the present study, we aim to determine the phenotypic traits based on antimicrobial susceptibility profile and genotypic characterization by verifying the presence of resistance determinants, virulence and toxin genes present in the CoNS causing clinical mastitis. We obtained 62 CoNS isolates from 167 mastitic milk samples collected from three different states of India. The 62 isolates comprises of 10 different CoNS species S. sciuri, S. haemolyticus, S. chromogenes, S. saprophyticus, S. xylosus, S. simulans, S. agnetis, S. epidermidis, S. gallinarum, and S. cohinii. Susceptibility screening against 11 antibiotics determined 45.16% isolates as multidrug resistant (resistant to more than two class of antibiotic, 46.74% resistant (one or two antibiotic class and 8.06% isolates were pan-sensitive (sensitive to all drugs. High resistance was observed against oxacillin and cefoxitin, whereas all isolates were susceptible toward vancomycin and linezolid. Fifty three isolates were methicillin resistant and 9 isolates were sensitive as determined by oxacillin susceptibility assay. The methicillin resistance gene, mecA was found in 95.16% isolates and staphylococcal cassette chromosome mec (SCCmec typing predominantly revealed Type III (n = 34 and Type V (n = 18. Interestingly, 11.9% of mecA positive isolates were oxacillin susceptible and referred as oxacillin susceptible mecA positive staphylococci (OS-MRS. Additionally, genes encoding for enterotoxin, (sea, seb, seh, see toxic shock syndrome (tsst, exfoliatin (eta, etb, etd and virulence (pvl, Y-hlg were also screened. Of all the genes examined, 67.74% of isolate were positive for the Y-hlg gene, followed by the sea gene in

Propiedades mecánicas de materiales compuestos de matriz de aluminio reforzados con intermetálicos

Directory of Open Access Journals (Sweden)

Torres, B.

2001-04-01

Full Text Available In this work 2124 aluminium matrix composites reinforced with Ni₃Al, NiAl, MoSiO₂ and Cr₃Si intermetallic powder particles have been investigated. For comparision purposes, unreinforced 2124 and reinforced with SiC have also been studied. In all cases, the same powder metallurgy route was used, i.e. the 2124 alloy was obtained by rapid solidification and the intermetallic particles by self-propagating high-temperature synthesis (SHS. The matrix and the intermetallics were mechanically blended, cold compacted and finally hot extruded. Tensile tests were carried out in T1 and T4 treatments. Results indicate that mechanical properties depend strongly on the tendence to form new phases at the matrixintermetallic interface during procesing and/or futher thermal treatments. The materials which present better properties are those that present less reaction between matrix and intermetallic reinforcement, i.e. MoSiO₂ and SiC reinforced composites.

En este trabajo se estudia el comportamiento mecánico de varios materiales compuestos de matriz de aluminio 2124 reforzados con partículas de los intermetálicos, Ni₃Al, NiAl, MoSiO₂ y Cr₃Si. Los resultados obtenidos se comparan con la aleación 2124 monolítica y con esa misma aleación reforzada con partículas del cerámico SiC. En todos los casos, se sigue la misma ruta de procesado pulvimetalúrgico a partir de polvos rápidamente solidificados, en el caso de la aleación 2124, y de la molienda mecánica de un tocho obtenido por síntesis autopropagada a temperatura elevada (SHS, para el refuerzo intermetálico. Matriz y reforzante se mezclan, mecánicamente, para, a continuación, compactar uniaxialmente en frío, procediéndose, finalmente, a la consolidación por extrusión. Las propiedades mecánicas se estudian mediante ensayos de tracción en estado T1 y T4. Los resultados obtenidos indican que las propiedades mec

Visión anatomo-mecánica del cuerpo humano en Descartes

OpenAIRE

Idoate García, Victor M.

1999-01-01

Pese a que Descartes concibe al cuerpo humano como constituido por un cuerpo (res extensa) y una alma (res cogitans), en este trabajo sólo se considerará la parte que corresponde a la descripción anatómico y mecánica del cuerpo humano.

Breve historia de la ventilación mecánica

OpenAIRE

Salas Segura, Donato A.

2000-01-01

Se dan unos adarmes sobre la historia del desarrollo de la ventilación mecánica asistida, una de las tecnologías médicas que más ha revolucionado el cuidado del paciente gravemente enfermo y que frecuentemente es ignorada en los textos y publicaciones de la historia de la medicina. UCR::Docencia::Salud::Facultad de Medicina::Escuela de Tecnologías en Salud

Detection of methicillin resistant Staphylococcus aureus (MRSA) from recreational beach using the mecA gene

Science.gov (United States)

Zulkifli, Aisya; Ahmad, Asmat

2015-09-01

Water samples were collected in triplicates from three different locations choosen from the recreational beach of Teluk Kemang, Port Dickson as sampling station including main area of recreation activity for the public. Bacteria were isolated from the water and cultured. Out of 286 presumptive Staphylococcus aureus enumerated by using culture method, only 4 (1.4 %) confirmed as Meticillin Resistant S. aureus (MRSA) based on PCR detection of mecA gene. Interestingly, all of MRSA detections were found at the main area of recreational activity. Our results suggested that public beaches may be reservoir for transmission of MRSA to beach visitors and PCR using the mecA gene is the fastest way to detect this pathogenic bacteria.

An S/T-Q cluster domain census unveils new putative targets under Tel1/Mec1 control

Directory of Open Access Journals (Sweden)

Cheung Hannah C

2012-11-01

Full Text Available Abstract Background The cellular response to DNA damage is immediate and highly coordinated in order to maintain genome integrity and proper cell division. During the DNA damage response (DDR, the sensor kinases Tel1 and Mec1 in Saccharomyces cerevisiae and ATM and ATR in human, phosphorylate multiple mediators which activate effector proteins to initiate cell cycle checkpoints and DNA repair. A subset of kinase substrates are recognized by the S/T-Q cluster domain (SCD, which contains motifs of serine (S or threonine (T followed by a glutamine (Q. However, the full repertoire of proteins and pathways controlled by Tel1 and Mec1 is unknown. Results To identify all putative SCD-containing proteins, we analyzed the distribution of S/T-Q motifs within verified Tel1/Mec1 targets and arrived at a unifying SCD definition of at least 3 S/T-Q within a stretch of 50 residues. This new SCD definition was used in a custom bioinformatics pipeline to generate a census of SCD-containing proteins in both yeast and human. In yeast, 436 proteins were identified, a significantly larger number of hits than were expected by chance. These SCD-containing proteins did not distribute equally across GO-ontology terms, but were significantly enriched for those involved in processes related to the DDR. We also found a significant enrichment of proteins involved in telophase and cytokinesis, protein transport and endocytosis suggesting possible novel Tel1/Mec1 targets in these pathways. In the human proteome, a wide range of similar proteins were identified, including homologs of some SCD-containing proteins found in yeast. This list also included high concentrations of proteins in the Mediator, spindle pole body/centrosome and actin cytoskeleton complexes. Conclusions Using a bioinformatic approach, we have generated a census of SCD-containing proteins that are involved not only in known DDR pathways but several other pathways under Tel1/Mec1 control suggesting new

Methicillin-resistant Staphylococcus aureus carriage among veterinary staff and dogs in private veterinary clinics in Hokkaido, Japan.

Science.gov (United States)

Ishihara, Kanako; Saito, Mieko; Shimokubo, Natsumi; Muramatsu, Yasukazu; Maetani, Shigeki; Tamura, Yutaka

2014-03-01

To explore the prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) in veterinary medical practices, MRSA carriage was tested among 96 veterinarians (Vets), 70 veterinary technicians (VTs) and 292 dogs with which they had contact at 71 private veterinary clinics (VCs) in Hokkaido, Japan. MRSA isolates were obtained from 22 Vets [22.9%] and 7 VTs [10%]. The prevalence of MRSA among Vets was as high as that found in an academic veterinary hospital in our previous study. In contrast, only two blood donor dogs and one dog with liver disease (1.0%, 3/292) yielded MRSA. All MRSA-positive dogs were reared or treated in different VCs, in each of which at least one veterinary staff member carrying MRSA worked. Sequence types (ST) identified by multilocus sequence typing, spa types, and SCCmec types for canine MRSA isolates (ST5-spa t002-SCCmec II [from two dogs] or ST30-spa t021-SCCmec IV [from a dog]) were concordant with those from veterinary staff members in the same clinics as the MRSA-positive dogs, with which they had potentially had contact. Most MRSA isolates from veterinary staff were the same genotype (SCCmec type II and spa type t002) as a major hospital-acquired MRSA clone in Japan. The remaining MRSA was the same genotypes as domestic and foreign community-associated MRSA. Measures against MRSA infection should be provided in private VCs. © 2014 The Societies and Wiley Publishing Asia Pty Ltd.

The ATM homologue MEC1 is required for phosphorylation of replication protein A in yeast

International Nuclear Information System (INIS)

Brush, G.S.; Morrow, D.M.; Hieter, P.; Kelly, T.J.

1996-01-01

Replication protein A (RPA) is a highly conserved single-stranded DNA-binding protein, required for cellular DNA replication, repair, and recombination. In human cells, RPA is phosphorylated during the S and G2 phases of the cell cycle and also in response to ionizing or ultraviolet radiation. Saccharomyces cerevisiae exhibits a similar pattern of cell cycle-regulated RPA phosphorylation, and our studies indicate that the radiation-induced reactions occur in yeast as well. We have examined yeast RPA phosphorylation during the normal cell cycle and in response to environmental insult, and have demonstrated that the checkpoint gene MEC1 is required for the reaction under all conditions tested. Through examination of several checkpoint mutants, we have placed RPA phosphorylation in a novel pathway of the DNA damage response. MEC1 is similar in sequence to human ATM, the gene mutated in patients with ataxia-telangiectasia (A-T). A-T cells are deficient in multiple checkpoint pathways and are hypersensitive to killing by ionizing radiation. Because A-T cells exhibit a delay in ionizing radiation-induced RPA phosphorylation, our results indicate a functional similarity between MEC1 and ATM, and suggest that RPA phosphorylation is involved in a conserved eukaryotic DNA damage-response pathway defective in A-T

Conserved binding of GCAC motifs by MEC-8, couch potato, and the RBPMS protein family

Science.gov (United States)

Soufari, Heddy

2017-01-01

Precise regulation of mRNA processing, translation, localization, and stability relies on specific interactions with RNA-binding proteins whose biological function and target preference are dictated by their preferred RNA motifs. The RBPMS family of RNA-binding proteins is defined by a conserved RNA recognition motif (RRM) domain found in metazoan RBPMS/Hermes and RBPMS2, Drosophila couch potato, and MEC-8 from Caenorhabditis elegans. In order to determine the parameters of RNA sequence recognition by the RBPMS family, we have first used the N-terminal domain from MEC-8 in binding assays and have demonstrated a preference for two GCAC motifs optimally separated by >6 nucleotides (nt). We have also determined the crystal structure of the dimeric N-terminal RRM domain from MEC-8 in the unbound form, and in complex with an oligonucleotide harboring two copies of the optimal GCAC motif. The atomic details reveal the molecular network that provides specificity to all four bases in the motif, including multiple hydrogen bonds to the initial guanine. Further studies with human RBPMS, as well as Drosophila couch potato, confirm a general preference for this double GCAC motif by other members of the protein family and the presence of this motif in known targets. PMID:28003515

Propriedades Mecânicas e Dinâmico-mecânicas de Composições de Policloropreno com Negro de Fumo Mechanical and Dynamic Mechanical Properties of Chloroprene Rubber Compositions with Carbon Black

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Agnes F. Martins

2002-01-01

Full Text Available As cargas são fundamentais em composições elastoméricas sendo classificadas, segundo desempenho mecânico, em reforçadoras ou não. O negro de fumo é a carga de reforço mais utilizada nessas composições, não só pelas excelentes propriedades que confere ao artefato, mas também pelo baixo preço e facilidade de processamento. As propriedades dinâmico-mecânicas de sistemas poliméricos são modificadas pela adição de cargas, o que acarreta mudanças nos módulos elástico (E' e viscoso (E", bem como na razão entre eles, isto é, a tangente de perda (tan delta. Neste trabalho, são estudadas as propriedades mecânicas e dinâmico-mecânicas de composições de policloropreno (CR com negro de fumo (NF. O teor de negro de fumo incorporado variou entre 0 e 45 phr. A composição contendo 40 phr de carga apresentou o melhor conjunto das propriedades estudadas.Often used in elastomeric compositions, fillers can be classified, according to their mechanical performance, as reinforcing or non-reinforcing fillers. Carbon black is the most used reinforcing filler in rubber compositions, either because of the excellent properties it confers to the rubber article, or due to its low cost and easy processing. When added to polymer systems, fillers are known to cause a considerable change in both dynamic moduli, viscous (E" and elastic (E', and also in the loss factor (tan delta, which is the ratio between those two parameters. In this work, the mechanical and dynamic mechanical properties of compositions of chloroprene rubber (CR with carbon black (CB were investigated. The filler content varied from 0 to 45 phr. The composition containing 40 phr of carbon black showed the best set of results.

Comparison of Biofilm Formation between Methicillin-Resistant and Methicillin-Susceptible Isolates of Staphylococcus aureus.

Science.gov (United States)

Ghasemian, Abdolmajid; Najar Peerayeh, Shahin; Bakhshi, Bita; Mirzaee, Mohsen

2016-07-01

The aim of this study was to compare the biofilm formation and the prevalence of biofilm-associated genes between the isolates of methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus. In total, 209 S. aureus isolates were collected. The antibiotic susceptibility test was conducted using nine antibiotics according to the guidelines of Clinical and Laboratory Standards Institute. Phenotypic biofilm formation was performed with microtiter plate assay. The polymerase chain reaction was employed to detect icaA, icaD, icaB, icaC, clfA, clfB, fnbA, fnbB, fib, cna, eno, ebps, bbp, mecA, and SCCmec types as well as agr group genes with specific primers. Sixty-four (30.62%) isolates were resistant to methicillin, and 54 (83%) MRSA harbored SCCmec III. Furthermore, 122 (58.3%) isolates belonged to agr group I. Twenty-six (36.1%) MRSA and 42 (28.9%) MSSA isolates were strong biofilm producers (no significant difference). The prevalence of icaA, icaD, icaB, and icaC genes in MSSA isolates was 71, 41, 76, and 72%, respectively. The frequency of clfA, clfB, fnbA, fnbB, fib, cna, eno, ebps, and bbp in MSSA was 100, 100, 56, 46, 74, 54, 78, 11, and 1%, respectively. However, in MRSA isolates, the frequency was 97, 97, 64, 51, 76, 56, 79, and 12% with no track of bbp, respectively. Statistical difference between MSSA and MRSA regarding biofilm formation and the frequency of all biofilm-encoding genes was not significant. The majority of the S. aureus isolates harbored clfA, clfB, eno, fib, icaA, and icaD genes.

ESPAMACS: el nuevo Registro Español de Asistencia Mecánica Circulatoria

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Paloma Martínez Cabeza

2016-10-01

Full Text Available ESPAMACS es el nuevo Registro Español de Asistencia Mecánica Circulatoria, que ha sido creado en el seno del Grupo de Trabajo de Asistencia Mecánica Circulatoria y Trasplante Cardiaco de la Sociedad Española de Cirugía Torácica-Cardiovascular (GRUTAT-SECTCV con el objetivo de registrar todas las asistencias, tanto de corto como de largo plazo, que se implanten en España. Técnicamente, es una base de datos «on-line» que permite a los usuarios introducir datos a tiempo real desde cualquier puesto con acceso a Internet. Está operativa desde octubre del 2014, sustituyendo a la anterior base de datos en formato Microsoft Excel en la que se recogieron los dispositivos implantados entre 2007 y 2012. En el presente artículo se justifica la necesidad de este registro en el actual escenario de tratamiento de la insuficiencia cardiaca, caracterizado por la progresión de la asistencia mecánica circulatoria y la limitada disponibilidad del trasplante cardiaco. Asimismo, se describen las características y el funcionamiento de ESPAMACS: propiedad, modo de acceso, planificación y desarrollo, financiación, objetivos, aspectos éticos, requisitos para participar, selección de pacientes, dispositivos incluidos, diseño, variables registradas, sistema de extracción de datos para su análisis estadístico y posterior elaboración de estudios científicos y control de calidad.

Ventilación mecánica asistida en el Hospital San Rafael de Alajuela

OpenAIRE

Salas Segura, Donato A.

1999-01-01

Se trata de un estudio observacional sobre el empleo de la ventilación mecánica en un hospital de 2do nivel sin unidad de cuidados intensivos. UCR::Docencia::Salud::Facultad de Medicina::Escuela de Medicina

Efeitos do tramadol sobre variáveis clínicas e limiar nociceptivo mecânico em equinos

OpenAIRE

Franco, Leandro Guimarães; Moreno, Juan Carlos Duque; Teixeira Neto, Antônio Raphael; Souza, Moisés Caetano e; Silva, Luiz Antônio Franco da

2014-01-01

Avaliaram-se os efeitos clínicos e o potencial antinociceptivo mecânico de diferentes doses de tramadol administradas por via intravenosa (IV) em equinos. Sete animais foram tratados com 1 (Tr1), 2 (Tr2) ou 3 (Tr3) mg kg-1de tramadol IV em um estudo cruzado do tipo cego e randomizado. Foram avaliados frequência cardíaca, frequência respiratória, temperatura retal, pressão arterial, nível de sedação, motilidade gastrointestinal, alterações comportamentais e limiar antinociceptivo mecânico (Von...

Fragilidad y comportamiento mecánico del esmalte dental

OpenAIRE

Rivera-Velásquez, C. A. (Camilo Alberto); Ossa, A. (Alexander); Arola, D. (Dwayne)

2012-01-01

El esmalte dental es el tejido duro más mineralizado del cuerpo humano. En este trabajo se estudiaron las propiedades mecánicas fundamentales de este tejido para terceros molares de pacientes jóvenes colombianos. Se establecieron la dureza, la tenacidad a la fractura aparente y la fragilidad del esmalte dental en función de la profundidad a partir de la superficie oclusal mediante técnicas de medición de microindentación. Se encontró que las mediciones de dureza son altamente dependi...

Complicaciones mecánicas de los accesos venosos centrales

OpenAIRE

Rodrigo Rivas, T.

2011-01-01

Las complicaciones mecánicas de los accesos venosos centrales son frecuentes, 2 a 15% y en ocasiones pueden comprometer la vida del paciente. Hay factores que determinan el riesgo de una u otra, que pueden ser modificados o enfrentados de diferente forma para minimizarlo. En esta puesta al día se describen las complicaciones más frecuentes o de mayor gravedad como son: el neumotórax, la embolia aérea, mal-posición del catéter, perforación de grandes venas, punción arterial, arritmias, trom...

El mantenimiento de la potencia mecánica en tenistas de categoría cadete

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J. M. Sarabia

2010-12-01

Full Text Available

El objetivo de este estudio fue comprobar la eficiencia de un entrenamiento de fuerza para el tren inferior y superior, basado en el mantenimiento de la potencia mecánica en jugadores cadetes de tenis. 18 tenistas (10 en el grupo experimental y 8 en el grupo control participaron en el estudio. Se realizó un periodo de adaptación anatómica (cinco semanas de duración previo al periodo de intervención en el grupo experimental. El periodo de intervención tuvo una duración de seis semanas donde se trabajó con los ejercicios de bench-press con peso libre y semi-squat en maquina Smith, con una carga estable del 60% de la fuerza dinámica máxima. Se evaluaron previa y posteriormente al periodo de intervención la potencia desarrollada en el tren superior como inferior con diferentes tests, tanto directos como indirectos. Los resultados parecen indicar que la metodología de entrenamiento basada en el mantenimiento de la potencia mecánica es eficiente para la mejora de la potencia máxima, permitiendo una optimización de las sesiones y minimizando el trabajo residual.
Palabras clave: Fuerza, sobrecarga, fallo mecánico

Evolución del estado mental del paciente sometido a la contención mecánica

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Alix Bohórquez

2010-12-01

Full Text Available La investigación es de naturaleza cuantitativa, descriptivo de corte prospectivo, en donde se pretende caracterizar el tiempo de reversión que se manifiesta en la contención mecánica de pacientes psiquiátricos. El colectivo en estudio correspondió a 30 pacientes con edades comprendidas entre los 15 a los 65 años, Servicio de Observación Constante (SOC en el ESE Hospital Mental Rudesindo Soto (HMRS durante el segundo semestre del 2009, de ambos sexos que manifestaron como características comunes: agitación psicomotriz, con variables alternas comprendidas en, etiología orgánica y número de contenciones implementadas en cada caso. Para realizar la aplicación de los instrumentos de recolección de información se creó un formato de valoración individual de la contención mecánica, el cual fue revisado y ajustado. Los resultado obtenidos indican que el 60% de la muestra es de género masculino, el cual el 30% comprenden edades entre los 35 a 44 años, en donde se evidencian alteraciones en la normalidad de signos vitales y componentes de las esferas mentales. Aunque los síntomas se revierten en un tiempo de 2 a 3 horas por lo cual se da retiro de la contención mecánica, el paciente continua confuso. Finalmente, se observa que la reversión de la contención mecánica en la mayoría de la muestra se presenta en tiempos de +/- 1.1 a 2 horas.

Propriedades mecânicas de espumas cerâmicas produzidas via "gelcasting" Mechanical properties of ceramic foams produced by gelcasting

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F. S. Ortega

2003-03-01

Full Text Available Cerâmicas porosas são materiais de grande interesse tecnológico, devido à associação de propriedades únicas como alta refratariedade e inércia química com alta permeabilidade, alta área superficial e baixa condutividade térmica. No entanto, o aumento da porosidade resulta, invariavelmente, na deterioração das propriedades mecânicas. Este trabalho faz uma investigação sobre as propriedades mecânicas de espumas cerâmicas obtidas pela aeração de suspensões associada à polimerização "in situ" de monômeros orgânicos previamente adicionados (processo gelcasting. A macroestrutura resultante deste processo é constituída por poros que tendem a uma geometria esférica, a qual minimiza a concentração de tensões mecânicas. Além disso, as paredes dos poros podem ser completamente densificadas, proporcionando uma microestrutura homogênea. A resistência mecânica de espumas cerâmicas com várias densidades foi avaliada por flexão em quatro pontos e por compressão. Os resultados mecânicos foram analisados através da estatística de Weilbull. O módulo elástico das amostras foi caracterizado pelo método de ressonância mecânica de barras. Os resultados obtidos possibilitam uma melhor compreensão dos fatores que determinam as propriedades mecânicas desta nova classe de material, fornecendo subsídios para futuros desenvolvimentos.Porous ceramics have great technological importance, since they combine ceramics unique properties, such as refractoriness and chemical resistance, with high surface area, high permeability and low thermal conductivity. Nevertheless, increasing porosity generally deteriorates the mechanical behavior of ceramics. In this work, the mechanical properties of ceramic foams produced by the aeration of ceramic suspensions associated to the polymerization of previously added monomers (gelcasting process is investigated. The macrostructure that results from this process is constituted of nearly

Reactividad y propiedades mecánicas de escoria de alto horno activada por álcalis

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Escalante-García, J. I.

2002-10-01

Full Text Available Investigations were carried out to characterize the reactivity and mechanical properties in blast furnace slag pastes activated by 5 alkali systems such as NaOH, waterglass and combinations of Na2CO3, Na2SO4 y Ca(OH2 in concentrations of 5%. Cubes of 5cm were prepared and cured under water for up to 120 days at 20 and 60°C. The highest compressive strengths were noted for the waterglass activation, followed by one of the combination of 3 compounds, while NaOH activation resulted in the lowest strengths. Increased temperatures favored the strength for the waterglass activation, outperforming those of the Portland cement paste used as control at all times, whereas it had a negative effect for all other activations. The reactivity of the systems, as obtained by measurements of non evaporable water and selective chemical dissolution, indicated that the slag is more reactive under the NaOH activation. Scanning electron microscopy by means of backscattered electrons confirmed the different reactivities and the mechanical properties observed.

Se realizaron estudios de caracterización de reactividad y propiedades mecánicas en pastas de escoria de alto horno activada por 5 sistemas alcalinos como NaOH, vidrio soluble y combinaciones de Na2CO3, Na2SO4 y Ca(OH2 en concentraciones de 5%. Se prepararon cubos de 5cm por lado y se curaron durante 120 días a 20 y 60°C bajo agua. Los valores mas altos de resistencia mecánica fueron registrados por el sistema de escoria activada con vidrio soluble, seguido por una de las combinaciones de 3 reactivos químicos, mientras que el desarrollo de propiedades mecánicas fue más pobre con la activación por NaOH. El aumento en la temperatura de curado favoreció la resistencia a la compresión de escoria con vidrio soluble, superando a la del cemento Portland a todos los tiempos de curado; para los otros sistemas el incremento de la temperatura de curado resultó perjudicial. En contraste con las

La imagen del Departamento de Ingeniería Mecánica

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Julio Mario Rodríguez Devis

1991-07-01

Full Text Available El presente trabajo extrae los principales puntos referentes al estudio de imagen de la Facultad de Ingenieria de la Universidad Nacional de Colombia, sede Bogotá, y se centra en el departamento de Ingenieria Mecánica. El estudio fue contratado a finales de 1989, y coordinado por el autor; como parte de una estrategia de la Facultad de vincularse más activamente al sector productivo.

Estudio de las propiedades mecánicas del sistema óseo

OpenAIRE

Alvaro Mendoza G.

2011-01-01

Los estudios adelantados fueron realizados para el área de Biomecánica, tratando de que su desarrollo fuera lo más científico posible; y aplicado al estudio del sistema óseo del hombre, ya que él posee un material que tiene un comportamiento que hace posible las aplicaciones de conceptos mecánicos y físicos de la Ingenlerla para su análisis.

Resolución por elementos finitos de problemas de mecánica de fluidos

OpenAIRE

Nigro, Norberto

1993-01-01

Tesis (DCI)--FCEFN-UNC, 1993 Recomienda dar respuesta a algunas de las dificultades que surgen en la simulación numérica de problemas de mecánica de fluídos mediante el método de los elementos finitos

Modelo mecánico para el análisis biomecánico del servicio de tenis

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Esperanza Navarro

2010-10-01

Full Text Available

El propósito de este artículo es plantear un nuevo modelo mecánico del cuerpo, adaptado a los gestos técnicos del tenis. El modelo consta de 28 puntos articulares, en él se definen barras y sólido-rígidos. Dicho modelo permite un estudio del gesto técnico completo. Se analizó un servicio filmado con dos cámaras a 250 fps de una jugadora con ranking WTA mundial 42. Los resultados reflejan la validez de dicho modelo ya que nos permite cuantificar la evolución de la energía de toda la cadena cinética.
Palabras Clave: Modelo, mecánico, biomecánica, servicio, tenis.

Molecular and phenotypic characteristics of methicillin-resistant Staphylococcus aureus isolated from hospitalized patients.

Science.gov (United States)

de Oliveira, Caio Ferreira; Morey, Alexandre Tadachi; Santos, Jussevania Pereira; Gomes, Ludmila Vilela Pereira; Cardoso, Juscélio Donizete; Pinge-Filho, Phileno; Perugini, Márcia Regina Eches; Yamauchi, Lucy Megumi; Yamada-Ogatta, Sueli Fumie

2015-07-30

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of infections acquired in both community and hospital settings. In this study, MRSA isolated from different sources of hospitalized patients was characterized by molecular and phenotypic methods. A total of 123 S. aureus isolates were characterized according to their genetic relatedness by repetitive element sequence based-PCR (REP-PCR), in vitro antimicrobial susceptibility profile, SCCmec typing and presence of seven virulence factor-encoding genes. REP-PCR fingerprinting showed low relatedness between the isolates, and the predominance of one specific lineage or clonal group was not observed. All isolates were susceptible to teicoplanin and linezolide. All isolates were resistant to cefoxitin and penicillin, and the majority were also resistant to one or more other antimicrobials. Fifty isolates (41.7%) were intermediately resistant to vancomycin. Most isolates harbored SCCmec type II (53.7%), followed by type I (22.8%), type IV (8.1%) and type III (1.6%). All isolates harbored at least two virulence factor-encoding genes, and the prevalence was as follows: coa, 100%; icaA, 100%; hla, 13.0%; hlb, 91.1%, hld, 91.1%; lukS-PV and lukF-PV, 2.4%; and tst, 34.1%. A positive association with the presence of hla and SCCmec type II, and tst and SCCmec type I was observed. This study showed the high virulence potential of multidrug-resistant MRSA circulating in a teaching hospital. A high prevalence of MRSA showing intermediate vancomycin resistance was also observed, indicating the urgent need to improve strategies for controlling the use of antimicrobials for appropriate management of S. aureus infections.

Estudio de las propiedades mecánicas del sistema óseo

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Alvaro Mendoza G.

1991-03-01

Full Text Available Los estudios adelantados fueron realizados para el área de Biomecánica, tratando de que su desarrollo fuera lo más científico posible; y aplicado al estudio del sistema óseo del hombre, ya que él posee un material que tiene un comportamiento que hace posible las aplicaciones de conceptos mecánicos y físicos de la Ingenlerla para su análisis.

Barreira capilar construída com resíduo pré-tratado mecânica e biologicamente

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Ronaldo Luis dos Santos Izzo

2013-12-01

Full Text Available O controle da entrada de água de chuva no interior do aterro de resíduos sólidos urbanos durante sua construção e após seu fechamento é crucial para manter o controle da geração de lixiviado. Este fator pode contribuir para a elevação de gastos com tratamento e monitoramento e para a instabilidade mecânica do aterro. Por esta razão, o sistema de cobertura final de um aterro de resíduos sólidos urbanos é decisivo ao controle da entrada de água no mesmo. Na maioria dos casos, o sistema de cobertura final é composto por solo compactado. Frequentemente, um solo adequado para a cobertura não é encontrado nos arredores do aterro; portanto, recursos têm que ser despendidos para o transporte do mesmo até o devido local. Uma alternativa seria a utilização de uma barreira capilar construída com resíduos pré-tratados mecânica e biologicamente. No entanto, o uso deste material para esta construção ainda não foi bem estudado, e as diversas variáveis envolvidas no funcionamento de uma barreira capilar construída com resíduos sólidos pré-tratados mecânica e biologicamente são desconhecidas. O objetivo deste trabalho foi analisar os parâmetros envolvidos no funcionamento de uma barreira capilar construída exclusivamente de resíduos sólidos urbanos pré-tratados mecânica e biologicamente. Observou-se que este utilizado como material de uma barreira capilar pode funcionar de maneira equivalente àquela construída com solo, sendo boa a sua capacidade de retenção da água de chuva.

Aislamientos de Staphylococcus aureus sensibles a meticilina relacionados genéticamente con el clon USA300, ¿origen de los aislamientos SARM de genotipo comunitario en Colombia?

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Javier Antonio Escobar-Pérez

2014-04-01

Full Text Available Introducción. USA300 es un linaje genético que se encuentra en aislamientos de Staphylococcus aureus sensibles (SASM y resistentes a meticilina (SARM. Actualmente, en Colombia las infecciones por SARM en hospitales y en la comunidad son causadas principalmente por un clon con genotipo comunitario (SARM-GC relacionado genéticamente con el clon USA300. El origen de esta variante es aún desconocido. Objetivo. Identificar y caracterizar aislamientos de S. aureus resistentes y sensibles a meticilina con el fin de aportar información para establecer un posible origen de los aislamientos SARM-GC en Colombia. Materiales y métodos. Se realizó una caracterización de aislamientos SASM relacionados con el clon USA300 detectados a partir de un análisis de 184 aislamientos de S. aureus (90 SARM y 94 SASM causantes de infecciones. La relación genética de los aislamientos se determinó por electroforesis en gel de campo pulsado (PFGE, tipificación de secuencias multilocus (MLST y tipificación del gen de la proteína A (spa. Resultados. De los 184 aislamientos, 27 (14,7 % presentaron características moleculares y relación genética con el clon USA300, y de ellos, 18 fueron SARM y nueve fueron SASM. Todos los aislamientos SARM relacionados con este clon albergaban un casete estafilocócico cromosómico mec (SCCmec IVc (3.1.2. En ningún aislamiento SASM se detectaron secuencias remanentes de SCCmec o una duplicación del sitio attB que evidenciaran la pérdida del casete. Conclusión. El origen de los aislamientos SARM-GC en Colombia probablemente se encuentre en la diseminación de clones SASM relacionados con el clon USA300 que adquirieron el SCCmec IVc posteriormente.

Influência do suporte e fixação anterior na resistência mecânica do fixador interno vertebral Influencia del soporte y de la fijación anterior sobre la resistencia mecánica del fijador interno vertebralartrodesis cervical anterior por hernia del disco cervica The influence of anterior reconstruction and fixation on the mechanical performance of an internal fixator

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Gisele Cristina Ale dos Santos

2009-03-01

Full Text Available OBJETIVO: avaliar a influência da reconstrução e fixação anterior no desempenho mecânico do fixador interno da coluna vertebral. MÉTODOS: foram formados três grupos experimentais de acordo com a reconstrução e fixação anterior: grupo I -sem suporte anterior; grupo II - com suporte anterior; grupo III - com suporte e fixação anterior. Os corpos de prova foram submetidos a ensaios mecânicos de flexo-compressão, flexão lateral e torção, realizados em máquina de universal de ensaios, tendo sido realizados dez ensaios para cada modalidade (flexo-compressão, flexão lateral e torção em cada grupo experimental, perfazendo um total de 90 ensaios mecânicos. As propriedades mecânicas estudadas foram: o momento-fletor, o torque e a rigidez obtidos a partir da curva carga x deflexão de cada ensaio mecânico. RESULTADOS: observou-se que a colocação do suporte e da fixação anterior aumentou a resistência mecânica nos ensaios de flexo-compressão. Nos ensaios de flexão lateral observou-se aumento da resistência mecânica somente com a fixação anterior. CONCLUSÃO: nos ensaios de torção o suporte anterior e a fixação anterior não aumentaram a resistência mecânica do sistema de fixação vertebral.OBJETIVO: evaluar la influencia de la reconstrucción y fijación anterior en el desempeño mecánico del fijador interno de la columna vertebral. MÉTODOS: fueron formados tres grupos experimentales de acuerdo com la reconstrucción y fijación anterior: grupo I- sin soporte anterior, grupo II- con soporte anterior y grupo III- con soporte y fijación anterior. Los cuerpos de prueba fueron sometidos a ensayos mecánicos de flexocompresión, flexión lateral y torción, realizados en la máquina universal de ensayos, habiéndose realizados 10 ensayos para cada modalidad (flexocompresión, flexión lateral y torción en cada grupo experimental,con untotal de 90 ensayos mecánicos. Las propiedades mecánicas estudiadas fueron el

Treatability studies on different refinery wastewater samples using high-throughput microbial electrolysis cells (MECs)

KAUST Repository

Ren, Lijiao; Siegert, Michael; Ivanov, Ivan; Pisciotta, John M.; Logan, Bruce E.

2013-01-01

High-throughput microbial electrolysis cells (MECs) were used to perform treatability studies on many different refinery wastewater samples all having appreciably different characteristics, which resulted in large differences in current generation. A de-oiled refinery wastewater sample from one site (DOW1) produced the best results, with 2.1±0.2A/m2 (maximum current density), 79% chemical oxygen demand removal, and 82% headspace biological oxygen demand removal. These results were similar to those obtained using domestic wastewater. Two other de-oiled refinery wastewater samples also showed good performance, with a de-oiled oily sewer sample producing less current. A stabilization lagoon sample and a stripped sour wastewater sample failed to produce appreciable current. Electricity production, organics removal, and startup time were improved when the anode was first acclimated to domestic wastewater. These results show mini-MECs are an effective method for evaluating treatability of different wastewaters. © 2013 Elsevier Ltd.

Treatability studies on different refinery wastewater samples using high-throughput microbial electrolysis cells (MECs)

KAUST Repository

Ren, Lijiao

2013-05-01

High-throughput microbial electrolysis cells (MECs) were used to perform treatability studies on many different refinery wastewater samples all having appreciably different characteristics, which resulted in large differences in current generation. A de-oiled refinery wastewater sample from one site (DOW1) produced the best results, with 2.1±0.2A/m2 (maximum current density), 79% chemical oxygen demand removal, and 82% headspace biological oxygen demand removal. These results were similar to those obtained using domestic wastewater. Two other de-oiled refinery wastewater samples also showed good performance, with a de-oiled oily sewer sample producing less current. A stabilization lagoon sample and a stripped sour wastewater sample failed to produce appreciable current. Electricity production, organics removal, and startup time were improved when the anode was first acclimated to domestic wastewater. These results show mini-MECs are an effective method for evaluating treatability of different wastewaters. © 2013 Elsevier Ltd.

Adesão às medidas preventivas de pneumonia associada à ventilação mecânica.

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Luany Caroline Adamovicz Bork

2015-01-01

Full Text Available Justificativa e Objetivos: Ressaltando a relevância da adoção de medidas preventivas de infecção para a realização de uma assistência livre de danos emergiu a necessidade de observar como a equipe de saúde aplica o bundle. Objetivou-se verificar a adesão de medidas preventivas de pneumonia pelos profissionais de saúde, da Unidade de Terapia Intensiva geral adulta de um hospital público, Ponta Grossa-PR. Métodos: Pesquisa transversal, de abordagem quantitativa, prospectiva e observacional, realizada no período de abril a julho de 2013. A amostra constituiu-se de 33 pacientes que estavam em ventilação mecânica, totalizando o registro de 1522 momentos de aplicações das medidas preventivas de pneumonia associada à ventilação mecânica (PAVM. Resultados: Dos 33 pacientes, 13 desenvolveram pneumonia, a média de idade foi de 59,72 anos e a prevalência foi do gênero feminino (44,44%. Verificou-se que os profissionais de saúde atenderam a cabeceira elevada dos leitos em média 69,80%, assim como aderiram à interrupção da sedação em média 66,66%, realizaram a higiene oral com clorexidina 94,61%, mantiveram o cuff do tubo orotraqueal (entre 20 e 25 mmH20 64,44%, adequaram o filtro de nebulizador para ficar dentro da validade 89,50% e em 93,4% das observações deixaram os circuitos livre de condensados. Analisou-se que o valor médio de dias passados em ventilação mecânica dos pacientes que adquiriram infecção foi de 15,85 (DP = 8,65 dias. Conclusão: Revela-se que quando a equipe aplica todas as medidas preventivas ao paciente sob ventilação mecânica há redução do risco de adquirir infecção no trato respiratório. DESCRITORES: Terapia intensiva; Pneumonia associada à ventilação mecânica; Infecção hospitalar; Equipe de assistência ao paciente.

Energy-positive wastewater treatment and desalination in an integrated microbial desalination cell (MDC)-microbial electrolysis cell (MEC)

Science.gov (United States)

Li, Yan; Styczynski, Jordyn; Huang, Yuankai; Xu, Zhiheng; McCutcheon, Jeffrey; Li, Baikun

2017-07-01

Simultaneous removal of nitrogen in municipal wastewater, metal in industrial wastewater and saline in seawater was achieved in an integrated microbial desalination cell-microbial electrolysis cell (MDC-MEC) system. Batch tests showed that more than 95.1% of nitrogen was oxidized by nitrification in the cathode of MDC and reduced by heterotrophic denitrification in the anode of MDC within 48 h, leading to the total nitrogen removal rate of 4.07 mg L-1 h-1. Combining of nitrogen removal and desalination in MDC effectively solved the problem of pH fluctuation in anode and cathode, and led to 63.7% of desalination. Power generation of MDC (293.7 mW m-2) was 2.9 times higher than the one without salt solution. The electric power of MDC was harvested by a capacitor circuit to supply metal reduction in a MEC, and 99.5% of lead (II) was removed within 48 h. A kinetic MDC model was developed to elucidate the correlation of voltage output and desalination efficiency. Ratio of wastewater and sea water was calculated for MDC optimal operation. Energy balance of nutrient removal, metal removal and desalination in the MDC-MEC system was positive (0.0267 kW h m-3), demonstrating the promise of utilizing low power output of MDCs.

Metodología para caracterizar el proceso de innovación tecnológica en la empresa sidero-mecánica cubana.

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García, Yulian

2009-12-01

Full Text Available El presente trabajo resume los resultados obtenidos mediante la aplicación de un procedimiento general de diagnóstico que permite caracterizar los procesos tecnológicos y de innovación en la industria sidero-mecánica cubana. El estudio se realizó en una muestra representativa de las empresas que integran el sector sidero-mecánico de la provincia de Villa Clara.

Alternate switching between MFC and MEC for H2O2 synthesis and residual removal in Bioelectro-Fenton system

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2016-01-01

Sustainable H2O2 supply and elimination of residual H2O2 are two key challenges to the Fenton processes treating recalcitrant contaminants. In this study, an innovative Bioelectro-Fenton system capable of alternate switching between microbial electrolysis cell (MEC) and microbial fuel cell (MFC......) mode of operation was developed to meet the challenges. In the MEC mode, H2O2 was electrochemically produced which reacts with Fenton’s reagent (Fe II) to form hydroxyradical. The residual H2O2 (unused H2O2) is removed as electron acceptor by switching the system to MFC mode. Complete decolorization...

Uso de clorexidina 2% gel e escovação mecânica na higiene bucal de pacientes sob ventilação mecânica: efeitos na pneumonia associada a ventilador The use of 2% chlorhexidine gel and toothbrushing for oral hygiene of patients receiving mechanical ventilation: effects on ventilator-associated pneumonia

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Maria Cristina de Avila Meinberg

2012-12-01

Full Text Available OBJETIVO: Avaliar os efeitos da higiene bucal com clorexidina 2% e escovação mecânica sobre a taxa de pneumonia associada a ventilador em uma população mista de pacientes sob ventilação mecânica prolongada. MÉTODOS: Estudo piloto prospectivo, aleatório e placebo-controlado. Foram incluídos pacientes sob ventilação mecânica, com menos de 24 horas de internação e cuja perspectiva de duração da ventilação mecânica era a de um período >72 horas. Os pacientes foram randomizados para o grupo clorexidina (gel com clorexidina a 2% e escovação mecânica ou grupo placebo (gel da mesma coloração e consistência e escovação mecânica na higiene bucal. RESULTADOS: A análise interina planejada foi realizada quando 52 pacientes foram incluídos, e o estudo foi interrompido precocemente. Um total de 28 pacientes foi incluído no grupo clorexidina/escovação mecânica e 24 no grupo placebo. As taxas de pneumonia associada a ventilador foram de 45,8% no grupo placebo e de 64,3% no grupo clorexidine/escovação mecânica (RR=1,4; IC95%=0,83-2,34;p=0,29. CONCLUSÃO: Devido a interrupção precoce por futilidade, não foi possível avaliar o impacto do uso de clorexidina a 2% e escovação mecânica na higiene bucal na incidência de pneumonia associada a ventilador nessa população heterogênea de pacientes críticos sob ventilação mecânica prolongada, não tendo sido evidenciado nenhum efeito benéfico dessa intervenção.OBJECTIVE: To evaluate the effects of oral chlorhexidine hygiene with toothbrushing on the rate of ventilator-associated pneumonia in a mixed population of critically ill patients under prolonged mechanical ventilation. METHODS: Prospective, randomized, and placebo-controlled pilot study. Patients who were receiving mechanical ventilation, had been admitted less than 24 hours prior, and were anticipated to require mechanical ventilation for more than 72 hours were included in the study. The patients were randomly

Materiales de la asignatura Mecánica de Fluidos (curso 2011-2012)

OpenAIRE

Salcedo Díaz, Raquel; Martín Gullón, Ignacio

2012-01-01

En este material están contenidos los conceptos básicos del curso de Mecánica de fluidos, de tercer curso de la titulación de Ingeniero Químico de la Universidad de Alicante. En dicho curso se aborda el flujo interno de fluidos, el flujo externo sólido-fluido y las operaciones de separación basadas en el flujo de fluidos.

A cfr-positive clinical staphylococcal isolate from India with multiple mechanisms of linezolid-resistance

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Vineeth Rajan

2014-01-01

Full Text Available Background & objectives: Linezolid, a member of the oxazolidinone class of antibiotics, has been an effective therapeutic option to treat severe infections caused by multidrug resistant Gram positive bacteria. Emergence of linezolid resistant clinical strains is a serious issue in the healthcare settings worldwide. We report here the molecular characterization of a linezolid resistant clinical isolate of Staphylococcus haemolyticus from India. Methods: The species of the clinical isolate was identified by 16S rRNA gene sequencing. The minimum inhibitory concentrations (MICs of linezolid, clindamycin, chloramphenicol and oxacillin were determined by E-test method. To elucidate the mechanism of linezolid-resistance, presence of cfr gene (chloramphenicol florfenicol resistance and mutations in 23S rRNA and ribosomal proteins (L3, L4 and L22 were investigated. Staphylococcal Cassette Chromosome mec (SCCmec typing was performed by multiplex PCR. Results: The study documented a rare clinical S. haemolyticus strain with three independent mechanisms of linezolid-resistance. The strain carried cfr gene, the only known transmissible mechanism of linezolid-resistance. The strain also possessed resistance-conferring mutations such as G 2576 T in domain V of 23S rRNA gene and Met 156 Thr in L3 ribosomal protein. The other ribosomal proteins (L4 and L22 did not exhibit mutations accountable for linezolid-resistance. Restriction digestion by NheI revealed that all the alleles of 23S rRNA gene were mutated. The isolate showed elevated MIC values (>256 ΅g ml -[1] of linezolid, clindamycin, chloramphenicol and oxacillin. Methicillin resistance was conferred by type I SCCmec element. The strain also harboured lsa(B gene which encodes an ABC transporter that can efflux clindamycin. Interpretation & conclusions: The present study reports the first clinical strain from India with transmissible and multiple mechanisms of linezolid-resistance. Judicious use of

Comportamiento mecánico del polimetilmetacrilato sometido a envejecimiento artificial mediante cámara xenotest

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Colom, X.

2001-04-01

Full Text Available In this investigation, the mechanical behavior of poly(methylmethacrylate due to aging in Xenon test chamber, using a xenon-arch lamp as a light radiation to simulate natural sun light has been studied. This work studies the mechanical properties (elongation at break. Young's modulus, tensile strength and toughness of PMMA samples exposed to different aging conditions (until 1560 h xenotest that correspond to 750 days exposure at natural light. The evolution of different mechanical properties characterizes the PMMA's process of degradation.

En el presente trabajo de investigación se ha estudiado el comportamiento mecánico del polimetilmetacrilato sometido a envejecimiento en cámara ''xenotest". El Xenotest es un aparato formado por una lámpara de arco de xenón que irradia en el intervalo 700-300 nm, simulando, adecuadamente, las condiciones de exposición a la luz solar. El estudio se centra en la caracterización de las propiedades mecánicas (módulo de Young, resistencia máxima a la tracción, deformación en el punto de rotura y tenacidad de las muestras de PMMA sometidas a las condiciones de envejecimiento durante períodos de tiempo variables (hasta 1.560 h xenotest que corresponden a una iluminación solar a la intemperie de 750 días. La evolución de las distintas propiedades mecánicas caracteriza el proceso de envejecimiento/degradación del PMMA.

Comparative proteomic analysis of extracellular proteins expressed by various clonal types of Staphylococcus aureus and during planktonic growth and biofilm development.

Science.gov (United States)

Atshan, Salman S; Shamsudin, Mariana N; Sekawi, Zamberi; Thian Lung, Leslie T; Barantalab, Fatemeh; Liew, Yun K; Alreshidi, Mateg Ali; Abduljaleel, Salwa A; Hamat, Rukman A

2015-01-01

Staphylococcus aureus is well known for its biofilm formation with rapid emergence of new clones circulating worldwide. The main objectives of the study were (1) to identify possible differences in protein expression among various and closely related clonal types of S. aureus, (2) to establish the differences in protein expression in terms of size of protein spots and its intensities between bacteria which are grown statically (biofilm formation) with that of under aeration and agitation, and (3) to compare the differences in protein expression as a function of time (in hours). In this study, we selected six clinical isolates comprising two similar (MRSA-527 and MRSA-524) and four different (MRSA-139, MSSA-12E, MSSA-22d, and MSSA-10E) types identified by spa typing, MLST and SCCmec typing. We performed 2D gel migration comparison. Also, two MRSA isolates (527 and 139) were selected to determine quantitative changes in the level of extracellular proteins at different biofilm growth time points of 12, 24, and 48 h. The study was done using a strategy that combines 2-DGE and LC-MS/MS analysis for absolute quantification and identification of the extracellular proteins. The 2DGE revealed that the proteomic profiles for the isolates belonging to the similar spa, MLST, and SCCmec types were still quite different. Among the extracellular proteins secreted at different time points of biofilm formation, significant changes in protein expression were observed at 48 h incubation as compared to the exponential growth at 12 h incubation. The main conclusion of the work is that the authors do observe differences among isolates, and growth conditions do influence the protein content at different time points of biofilm formation.

La mecánica ilustrada en los ingenieros militares españoles. El proyecto de los almacenes de pólvora (1715-1798

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Lluis i Ginovart, J.

2015-09-01

Full Text Available The catenary arches were part of the great structural success of the modernist architecture, and especially in the Gaudí’s work. The study of the Spanish military engineers’ projects shows that they were the first that introduced in the Spanish territory in the first third of the eighteenth century. Knowledge and the attempt to apply this type of structure, especially in the construction of Powder-Magazines, will demonstrate the knowledge of the scientific theory of these structures made by Hooke. The study of pre-scientific Mechanics was claimed by Juan de Herrera in the Academy of Mathematics (1583, as it is scientific Mechanics at the Academy of Barcelona (1720. For this reason and due to the use of catenary arch and vault, this will show that they provided the bases of modern mechanic.Los arcos catenarios formaron parte del gran éxito estructural de la arquitectura modernista y, especialmente, de la obra de Gaudí. El estudio de los proyectos de los ingenieros militares españoles, demuestra que fueron ellos los primeros que los introdujeron en el territorio español en el primer tercio del siglo XVIII. El conocimiento y el intento de aplicación de este tipo de estructuras, especialmente en la construcción de polvorines, demostraría el conocimiento de la teoría científica de estas estructuras formulada por Hooke. El estudio de la Mecánica pre-científica fue reclamado por Juan de Herrera en la Academia de Matemáticas (1583, al igual que lo será la Mecánica científica en la Academia de Barcelona (1720. Por ello y ante la utilización del arco y bóveda catenaria, se demostraría también que aportaron las bases de la Mecánica moderna.

Accuracy of phenotypic methicillin susceptibility methods in the detection of Staphylococcus aureus isolates carrying different SCCmec types

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Pricilla DM de Matos

2010-11-01

Full Text Available A total of 138 isolates, 118 methicillin-resistant Staphylococcus aureus (MRSA isolates (staphylococcal cassette chromosome type II, 20 isolates, type III, 39 isolates and type IV, 59 isolates and 20 methicillin-sensitive S. aureus isolates were evaluated by phenotypic methods: cefoxitin and oxacillin disk diffusion (DD, agar dilution (AD, latex agglutination (LA, oxacillin agar screening (OAS and chromogenic agar detection. All methods showed 100% specificity, but only the DD tests presented 100% sensitivity. The sensitivity of the other tests ranged from 82.2% (OAS-98.3% (AD. The LA test showed the second lowest sensitivity (86.4%. The DD test showed high accuracy in the detection of MRSA isolates, but there was low precision in the detection of type IV isolates by the other tests, indicating that the genotypic characteristics of the isolates should be considered.

Accuracy of phenotypic methicillin susceptibility methods in the detection of Staphylococcus aureus isolates carrying different SCCmec types.

Science.gov (United States)

Matos, Pricilla D M de; Schuenck, Ricardo P; Cavalcante, Fernanda S; Caboclo, Roberta M F; Santos, Kátia Regina N dos

2010-11-01

A total of 138 isolates, 118 methicillin-resistant Staphylococcus aureus (MRSA) isolates (staphylococcal cassette chromosome type II, 20 isolates, type III, 39 isolates and type IV, 59 isolates) and 20 methicillin-sensitive S. aureus isolates were evaluated by phenotypic methods: cefoxitin and oxacillin disk diffusion (DD), agar dilution (AD), latex agglutination (LA), oxacillin agar screening (OAS) and chromogenic agar detection. All methods showed 100% specificity, but only the DD tests presented 100% sensitivity. The sensitivity of the other tests ranged from 82.2% (OAS)-98.3% (AD). The LA test showed the second lowest sensitivity (86.4%). The DD test showed high accuracy in the detection of MRSA isolates, but there was low precision in the detection of type IV isolates by the other tests, indicating that the genotypic characteristics of the isolates should be considered.

Texto guía mecánica básica

OpenAIRE

De la Cruz Morales, Claudia Jenny

2014-01-01

EI siguiente texto consta de la unión de los conceptos básicos de las asignaturas estática y mecánica de materiales, que se dictan en la carrera de Ingeniería Civil, de la Facultad de Minas; con algunos ejemplos y ejercicios desarrollados, para explicar conceptos, como otros propuestos, tomados en su mayoría de las referencias utilizadas. En su primera etapa se presentan generalidades de la estática, en cuanto al manejo de vectores, cuerpo rígido, equilibrio de cuerpo rígido entre otros y alg...

Caracterización mecánica de uniones adhesivas caucho-metal

OpenAIRE

Gómez Gómez, Fabián Esteban; Escobar Trujillo, Santiago

2011-01-01

Este proyecto tiene como objetivo principal la caracterización de uniones adhesivas caucho-metal realizando tratamientos superficiales a los sustratos -- Los tratamientos utilizados fueron de tipo mecánico (granallado) y químico (Primer) y tienen como finalidad modificar superficialmente uno de los sustratos para establecer si la resistencia de la unión adhesiva se modifica -- Para ello, se fabrican probetas tipo sándwich de caucho y metal y se ensayan a tracción de acuerdo a la norma ISO 182...

Reciclagem de carcaças de monitores: propriedades mecânicas e morfológicas

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Adjanara P. Gabriel

2013-01-01

Full Text Available A substituição da tecnologia CRT (cathode ray tube utilizada em televisores e monitores, há mais de 60 anos, pelas novas tecnologias de Plasma, LCD (liquid crystal display e LED (light-emitting diode tem gerado grande quantidade de resíduos. Não existem estatísticas oficiais da quantidade de resíduos gerados no Brasil, contudo, para alguns países, como os EUA, a China e Taiwan, estimam-se descartes anuais de 3,2 milhões, 5 milhões e 1 milhão de televisores e monitores, respectivamente. Os monitores são compostos por polímeros, metais e cerâmicas, incluindo alguns materiais tóxicos. Este trabalho está focado na caracterização e reciclagem da carcaça polimérica dos monitores CRT. Foram coletados monitores danificados ou obsoletos e as carcaças foram separadas por marca, caracterizadas, cominuídas e injetadas para obter corpos de provas para os ensaios mecânicos. A caracterização mostrou que as carcaças, independentemente da marca, utilizam o mesmo material polimérico, o ABS (Acrilonitrila Butadieno Estireno. Os resultados dos ensaios mecânicos apresentaram variações nas diferentes marcas, provavelmente por possuírem composições diferenciadas. Esta variação também foi verificada analisando a superfície de fratura dos corpos de prova após o ensaio de tração. Com base nos resultados pode-se concluir que o material reciclado apresentou desempenho mecânico satisfatório, viabilizando tecnicamente a sua reciclagem.

Genotyping of Methicillin Resistant Staphylococcus aureus Strains Isolated from Hospitalized Children

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Mouna Ben Nejma

2014-01-01

Full Text Available Community associated methicillin resistant Staphylococcus aureus (CA-MRSA is an emerging pathogen increasingly reported to cause skin and soft tissue infections for children. The emergence of highly virulencet CA-MRSA strains in the immunodeficiency of young children seemed to be the basic explanation of the increased incidence of CA-MRSA infections among this population. The subjects of this study were 8 patients hospitalized in the Pediatric Department at the University Hospital of Monastir. The patients were young children (aged from 12 days to 18 months who were suffering from MRSA skin infections; two of them had the infections within 72 h of their admission. The isolates were classified as community isolates as they all carried the staphylococcal cassette chromosome mec (SCCmec IV and pvl genes. Epidemiological techniques, pulsed-field gel electrophoresis (PFGE and multilocus sequence typing (MLST, were applied to investigate CA-MRSA strains. Analysis of molecular data revealed that MRSA strains were related according to PFGE patterns and they belonged to a single clone ST80. Antimicrobial susceptibility tests showed that all strains were resistant to kanamycin and 2 strains were resistant to erythromycin.

Determinación de la presencia de fatiga mecánica en materiales cerámicos

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Casellas, D.

1999-04-01

Full Text Available It is well known that ceramic materials are highly susceptible to environmental assisted subcritical crack growth. In addition, this subcritical crack growth could be also related to cyclic loading (mechanical fatigue. This type of behaviour is not observed either in glasses nor in traditional ceramics. However this phenomena is clearly active in many advanced ceramics. The aim of this work is to obtain a procedure for detecting the presence of cyclic fatigue in ceramic materials. This procedure attempts to obtain cyclic fatigue life estimations and to compare it with the static loading experimental results. Through this comparisons it is possible to asses whether the cyclic fatigue is acting or not. Finally some calculations are conducted in ceramic materials (alumina, mullite and ZTA with natural and indentation flaws.

Los materiales cerámicos son susceptibles al crecimiento de fisuras por la acción combinada del medio ambiente y la aplicación de carga (fatiga estática. Por otra parte, el crecimiento subcrítico de fisuras en cerámicas también puede ser producido por la aplicación de cargas fluctuantes (fatiga mecánica. Este fenómeno no se observa en vidrios ni en cerámicas monocristalinas, pero si en muchos de los llamados materiales cerámicos avanzados. En este trabajo se describe una metodología utilizada para detectar la presencia de fatiga mecánica en materiales cerámicos, basada en la obtención de estimaciones de la vida a fatiga del material bajo cargas fluctuantes y su comparación con los resultados experimentales bajo carga constante. Este método se ha aplicado a fisuras naturales y de indentación en algunos materiales cerámicos (mullita, alúmina y ZTA.

Propiedades mecánicas del acero de refuerzo utilizado en Colombia Propiedades mecánicas del acero de refuerzo utilizado en Colombia

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Victoria González Quintana

2005-04-01

Full Text Available Se presentan resultados del análisis estadístico aplicado al estudio experimental que de- termina las propiedades mecánicas de aceros colombianos sometidos a cargas monotónicas de tracción. Se obtienen curvas típicas de esfuerzo-deformación que permiten caracterizar aceros nacionales estudiados haciendo énfasis en las variables que determinan el cambio de comportamiento del materialA statistical analysis applied to a experimental study that determines the mechanical properties of steels produced in Colombia subjected to monotonic loads of tension is presented. Typical stress-strain diagram that allow to characterize these steels making emphasis in the variables that determine the change of behaviour of the materia are presented.

Efetividade da rizotomia facetária por radiofrequência na lombalgia mecânica crônica Efectividad de la rizotomía facetaria en lumbago mecánico Effectiveness of radiofrequency facet rhizotomy in the treatment of mechanical back pain

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Lourimar Octaviano de Tolêdo

2011-01-01

Full Text Available OBJETIVO: Avaliar a efetividade da rizotomia facetária lombar por radiofreqüência no tratamento da dor lombar mecânica. MÉTODOS: Estudo prospectivo de 23 pacientes tratados com rizotomia por radiofrequência devido à dor lombar mecânica. O registro da intensidade da dor foi medido através de pontuação pela escala visual analógica (EVA e o número de analgésicos administrado a cada paciente no pré-operatório e nos controles de 3, 6 e 12 meses de pós-operatórios. RESULTADOS: Foi observado um declínio significativo da intensidade da dor (p OBJETIVO: Evaluar la efectividad de la rizotomía por radiofrecuencia facetaria lumbar en el tratamiento del lumbago mecánico. MÉTODOS: Estudio prospectivo de 23 pacientes tratados con rizotomía por radiofrecuencia en lumbago mecánico. El registro de la intensidad del dolor se midió por la puntuación de la escala analógica visual (VAS y el número de analgésicos administrados a cada paciente antes de la operación, y 3, 6 y 12 meses después de la intervención. RESULTADOS: Se observó una disminución significativa en la intensidad del dolor (p OBJECTIVE: To evaluate the effectiveness of radiofrequency lumbar facet rhizotomy in the treatment of mechanical low back pain. METHODS: Prospective study of 23 patients treated with radiofrequency rhizotomy in mechanical low back pain. The pain intensity was measured by the visual analog scale (VAS and the number of analgesics administered for each patient preoperatively and 3, 6 and 12 months postoperatively. RESULTS: We observed a significant decline in pain intensity (p<0.0001 in patients. CONCLUSIONS: In the series of patients assessed the treatment was effective in relieving symptoms of mechanical low back pain and the use of analgesics after the procedure was lower.

Detecção do gene mecA em estafilococos coagulase negativa resistentes à oxacilina isolados da saliva de profissionais da enfermagem Detection of mecA gene in oxacillin-resistant coagulase-negative staphylococci isolated from the saliva of nursing professionals

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Juliana de Oliveira Rosa

2009-08-01

Full Text Available Estafilococos coagulase negativa estão frequentemente associados às infecções nosocomiais e os profissionais da saúde podem ser reservatório e dissemina-los no hospital e comunidade. O objetivo desse estudo foi identificar espécies de estafilococos coagulase negativa isolados da saliva de profissionais da enfermagem, determinar o perfil de resistência e detectar o gene mecA. Foram selecionados 100 estafilococos coagulase negativa, sendo 41 identificados como Staphylococcus epidermidis, 25 Staphylococcus saprophyticus, 18 Staphylococcus haemolyticus, 8 Staphylococcus cohnii, 4 Staphylococcus lugdunenses, 3 Staphylococcus capitis, e 1 Staphylococcus Simulans. Desses, 32% apresentaram resistência à oxacilina, 84,4% à mupirocina, 32% à cefoxitina, e todos sensíveis a vancomicina. Dos estafilococos coagulase negativa resistentes à oxacilina, 93,7% desenvolveram-se no agar oxacilina (6µg/ml e o gene mecA foi detectado em 75%. Os resultados sinalizam que maiores investimentos devem ser direcionados a identificação das espécies de estafilococos coagulase negativa nas instituições de saúde e na comunidade.Coagulase-negative staphylococci are frequently associated with nosocomial infections, and healthcare professionals can be reservoirs and spread them in hospitals and in the community. The aim of this study was to identify species of coagulase-negative staphylococci isolated from the saliva of nursing professionals, determine the resistance profile and detect the mecA gene. One hundred coagulase-negative staphylococci were selected: 41 were identified as Staphylococcus epidermidis, 25 as Staphylococcus saprophyticus, 18 as Staphylococcus haemolyticus, eight as Staphylococcus cohnii, four as Staphylococcus lugdunenses, three as Staphylococcus capitis and one as Staphylococcus simulans. Of these, 32% presented oxacillin resistance, 84.4% mupirocin resistance and 32% cefoxitin resistance, and all were vancomycin sensitive. Among the

Comparison of different phenotypic methods of detection of methicillin resistance in staphylococcus aureus with the molecular detection of mec-a gene

International Nuclear Information System (INIS)

Zeeshan, M.; Jabeen, K.; Irfan, S.; Parween, Z.; Zafar, A.

2007-01-01

To evaluate accuracy, cost-effectiveness and ease to perform different phenotypic methods i.e. Cefoxitin 30 micro g disc, Oxacillin 1micro g disc and Oxacillin agar screening plate (6 micro g/ml) for early and accurate identification of MRSA by comparing with the detection of mec-A gene in our clinical isolates. Out of 200 clinical samples, conventional Polymerase Chain Reaction (PCR) was done on 62 pure biochemically identified S. aureus isolates for mec-A gene detection. Phenotypic methods for detecting methicillin sensitivity (Cefoxitin 30 microg disc, Oxacillin 1 micro g disc and Oxacillin agar screening plate) were also used according to the recommended incubation time, duration and temperature on the same isolates. Out of 62 isolates of S. aureus, mec-A gene were detected (MRSA) in 32, whereas 30 were mec-A gene negative (MSSA). Cefoxitin disc and agar screening plate correctly identify all MRSA isolates with the sensitivity and specificity of 100%. Single isolate was false, positively detected as sensitive with Oxacillin 1g disc, due to which, the sensitivity and negative predictive value of this method were reduced to 96.9% and 96.8% respectively, while positive predictive value and specificity remained 100%. Comparing different phenotypic methods for MRSA screening in routine microbiology laboratory, Cefoxitin disc and Oxacillin agar screening has better sensitivity and specificity comparative to Oxacillin disc. However, Cefoxitin disc can be preferred especially for small laboratories because it is easy to perform, do not require special technique and media preparation is consequently more cost-effective. (author)

Inducción de la biosíntesis local de antocianinas en frutos de Myrciaria dubia mediante lesiones mecánicas

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Daniel Motta Santillán

2014-12-01

Full Text Available En las plantas las antocianinas cumplen roles fundamentales en sus interacciones con el medio ambiente, son una de las líneas de defensa contra los radicales libres, la radiación ultravioleta y el ataque de patógenos. Observaciones realizadas muestran que los frutos de M. dubia acumulan antocianinas alrededor de lesiones mecánicas probablemente causadas por insectos. Por tanto, hemos probado la hipótesis que produciendo lesiones mecánicas en frutos verdes de M. dubia se induce la biosíntesis local de antocianinas. De tres plantas en fructificación de la colección de germoplasma del INIA se seleccionaron aleatoriamente 40 frutos verdes (25 ± 5 mm de Ø y se causaron lesiones mecánicas con estilete o bisturí al 75% de ellos. Posteriormente, se registró el porcentaje de acumulación de antocianinas por área superficial del fruto a las 0, 24, 48 y 72 horas. Se observó acumulación de antocianinas en ~10% (24 horas, ~30% (48 horas y ~70% (72 horas del área superficial de los frutos. En conclusión, las lesiones mecánicas causadas en frutos de M. dubia inducen la biosíntesis local de antocianinas, probablemente como un mecanismo de defensa efectivo desarrollado por esta especie. La comprensión de los mecanismos moleculares implicados en esta respuesta fisiológica nos permitirá establecer las bases para la mejora genética de esta especie.

Inducción de la biosíntesis local de antocianinas en frutos de Myrciaria dubia mediante lesiones mecánicas

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Daniel Motta-Santillán

2015-01-01

Full Text Available En las plantas las antocianinas cumplen roles fundamentales en sus interacciones con el medio ambiente, son una de las líneas de defensa contra los radicales libres, la radiación ultravioleta y el ataque de patógenos. Observaciones realizadas muestran que los frutos de M. dubia acumulan antocianinas alrededor de lesiones mecánicas probablemente causadas por insectos. Por tanto, hemos probado la hipótesis que produciendo lesiones mecánicas en frutos verdes de M. dubia se induce la biosíntesis local de antocianinas. De tres plantas en fructificación de la colección de germoplasma del INIA se seleccionaron aleatoriamente 40 frutos verdes (25 ± 5 mm de Ø y se causaron lesiones mecánicas con estilete o bisturí al 75% de ellos. Posteriormente, se registró el porcentaje de acumulación de antocianinas por área superficial del fruto a las 0, 24, 48 y 72 horas. Se observó acumulación de antocianinas en ~10% (24 horas, ~30% (48 horas y ~70% (72 horas del área superficial de los frutos. En conclusión, las lesiones mecánicas causadas en frutos de M. dubia inducen la biosíntesis local de antocianinas, probablemente como un mecanismo de defensa efectivo desarrollado por esta especie. La comprensión de los mecanismos moleculares implicados en esta respuesta fisiológica nos permitirá establecer las bases para la mejora genética de esta especie.

Propiedades mecánicas de tres marcas de arcos ortodóncicos de níquel-titanio termoactivados. Estudio in vitro

OpenAIRE

Ramos Torres, Viviana; Soldevilla Galarza, Luciano; Mattos Vela, Manuel

2014-01-01

La selección óptima de los alambres ortodóncicos permite al profesional realizar el tratamiento de manera eficiente; por ello, se requiere el conocimiento de las propiedades mecánicas básicas, las cuales no son reveladas por sus fabricantes. El estudio tuvo como objetivo comparar las propiedades mecánicas (tensión en la zona de activación constante, elongación en la zona de activación constante, resistencia máxima y límite de ruptura) de tres marcas de alambres ortodóncicos de níquel-titanio ...

Mistr tesař diachronní lexikografie (Igor Němec a Staročeský slovník)

Czech Academy of Sciences Publication Activity Database

Nejedlý, Petr

2015-01-01

Roč. 98, č. 1 (2015), s. 1-10 ISSN 0027-8203 R&D Projects: GA ČR GAP406/10/1153 Institutional support: RVO:68378092 Keywords : diachronic lexicography * lexicological analysis * Old Czech Dictionary * Igor Němec Subject RIV: AI - Linguistics

PENERAPAN METODE INTERACTIVE DEVELOPMENT DALAM PEMBELAJARAN KETERAMPILAN BERBICARA DI MERCURY EDUCATION CENTRE (MEC PAMEKASAN

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Kristanti Ayuanita

2018-03-01

Full Text Available The purpose of this study is to know how is the application of Interactive development method in teaching speaking skill in Mercury Education Centre (MEC Pamekasan, what are the difficulties in applying interactive development method in teaching speaking skill in Mercury Education Centre (MEC Pamekasan. The researcher uses qualitative approach with descriptive kind of research. The data collection means are observation, interview, field notes and data documentation. To check the validity of the data, the researcher uses the techniques of  longer observation, triangulation. The research result show that the interactive development method started with giving motivation in the beginning and the end of the class. After that the students are given some minutes to pronounce vocabulary and to make sentences to do debate or presentation. While the difficulties faced are the different ability to memorize words, the large amount of the students in a class, the students’ condition, and also the different atmosphere between the school and Mercury. The effort done by the teacher coping these difficulties are giving more motivation, giving reward or appreciation, making the target system arranging to send the mentor to go on seminar on it.

Ventilação mecânica na crise de asma aguda Mechanical ventilation in acute asthma crisis

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Carmen Sílvia Valente Barbas

2007-06-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: Em 2000, foi publicado o II Consenso Brasileiro de Ventilação Mecânica. Desde então, o conhecimento na área da ventilação mecânica avançou rapidamente, com a publicação de inúmeros estudos clínicos que acrescentaram informações importantes para o manuseio de pacientes críticos em ventilação artificial. Além disso, a expansão do conceito de Medicina Baseada em Evidências (MBE determinou a hierarquização das recomendações clínicas, segundo o rigor metodológico dos estudos que as embasaram. Essa abordagem explícita vem ampliando a compreensão e a aplicação das recomendações clínicas. Por esses motivos, a AMIB - Associação de Medicina Intensiva Brasileira - e a SBPT - Sociedade Brasileira de Pneumologia e Tisiologia - julgaram conveniente a atualização das recomendações descritas no Consenso anterior. Dentre os tópicos selecionados a Ventilação Mecânica na Crise de Asma foi um dos temas propostos. O objetivo deste estudo foi descrever os pontos mais importantes relacionados à ventilação mecânica durante a crise de asma e sugerir as principais abordagens terapêuticas. MÉTODO: Objetivou-se chegar a um documento suficientemente sintético, que refletisse a melhor evidência disponível na literatura. A revisão bibliográfica baseou-se na busca de estudos através de palavras-chave e em sua gradação conforme níveis de evidência. As palavras-chave utilizadas para a busca foram: Ventilação mecânica na asma: asthma and mechanical ventilation. RESULTADOS: São apresentadas recomendações quanto aos modos ventilatórios e aos parâmetros a serem aplicados quando do ajuste do ventilador, além da monitoração recomendada. Apresentam-se ainda, técnicas alternativas que possam ser utilizadas. CONCLUSÕES: Estratégias protetoras de ventilação mecânica são recomendadas durante a ventilação mecânica de paciente asmático grave.BACKGROUND AND OBJECTIVES: The II Brazilian

Relação das propriedades mecânicas e densidade de postes de madeira de eucalipto com seu estado de deterioração

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Rafael Colombo Abruzzi

2012-12-01

Full Text Available Este trabalho apresenta correlações obtidas entre propriedades mecânicas, densidade e o estado de deterioração de postes de eucalipto novos e retirados de serviço. O estado de deterioração foi determinado por inspeções em campo de postes da rede de distribuição de energia elétrica no sul do Brasil. Postes em diferentes estados de deterioração foram retirados da rede para os ensaios de flexão estática e medidas de densidade. Os testes mecânicos indicaram que os valores médios da resistência a flexão e da rigidez decrescem com o estado de deterioração do eucalipto. Entretanto, verificou-se uma grande variação nessas medidas com diferentes classes de deterioração apresentando resistência mecânica residual similar. Esse comportamento pode ser explicado pela influência da densidade da madeira nas correlações entre propriedades mecânicas e o estado de deterioração dos postes. Madeiras menos densas podem apresentar baixa resistência mecânica residual mesmo sem apresentar sinais de deterioração. O estudo da caracterização da madeira de eucalipto indicou que o estado de deterioração avaliado pela inspeção em campo, por si só não é um bom indicativo para prever a durabilidade das estruturas de madeiras, fazendo-se necessária uma análise preliminar da densidade da mesma.

Avaliação das principais propriedades físicas e mecânicas da madeira de Eucalyptus benthamii Maiden et Cambage

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Bruna Verediana Müller

Full Text Available O presente estudo teve como objetivo determinar as propriedades físicas e mecânicas da madeira de Eucalyptus benthamii Maiden et Cambage. Foram determinadas as seguintes propriedades físicas: massa específica aparente a 12 e 0% de umidade, massa específica aparente básica e os coeficientes de contração, além das propriedades mecânicas, por meio dos ensaios de flexão estática, compressão paralela às fibras, cisalhamento e dureza, para a idade de seis anos. Com base nos resultados obtidos na determinação das propriedades físicas, a madeira de E. benthamii, na idade estudada, pode ser classificada como moderadamente pesada e dimensionalmente instável. Em relação às propriedades mecânicas, de modo geral, a espécie apresentou baixa resistência, o que possivelmente está relacionado com a grande proporção de madeira juvenil presente no material estudado.

Evolución de las propiedades mecánicas con la temperatura de cintas amorfas Mg10Ni10Y

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Torrijos, M. A.

2006-02-01

Full Text Available The mechanical behaviour by tensile strength test from room temperature to 350 ºC in the rapidly solidified Mg-10Ni-10Y (at. % ribbon has been studied. To determine the effect of yttrium additions the results are compared with those of Mg-11Ni studied in a previous work. Before studding the mechanical behavior of the material the thermal stability of the amorphous ribbon and the crystallization reactions were determined by DSC experiments. Results show that yttrium stabilizes the amorphous phase but it has not reinforcement effect. The tensile strength and elongation to failure values of the ternary alloy are lower than those of Mg-11Ni

El objetivo de este estudio es la caracterización mecánica, mediante ensayos de tracción, desde temperatura ambiente hasta 350 °C, de una aleación amorfa de composición Mg-10Ni-10Y (% at. obtenida mediante solidificación rápida por la técnica de la rueda. Se analiza la influencia de la adición de itrio al Mg-Ni para lo cual los resultados se comparan con los de la aleación binaria Mg-11Ni estudiada previamente. Antes de iniciar la caracterización mecánica del material, se realizó un estudio mediante calorimetría diferencial de barrido para comprobar la naturaleza amorfa de la cinta, analizar su estabilidad térmica y conocer las transformaciones que experimenta hasta la cristalización. Los resultados indican que el itrio es un estabilizador de la fase amorfa pero no mejora las propiedes mecánicas de la cinta binaria. Los valores de resistencia mecánica y alargamiento a rotura medidos en la cinta con itrio son menores que los obtenidos para la aleación binaria.

Mutagenic potency of MMS-induced 1meA/3meC lesions in E. coli.

Science.gov (United States)

Nieminuszczy, Jadwiga; Mielecki, Damian; Sikora, Anna; Wrzesiński, Michał; Chojnacka, Aleksandra; Krwawicz, Joanna; Janion, Celina; Grzesiuk, Elzbieta

2009-12-01

The mutagenic activity of MMS in E. coli depends on the susceptibility of DNA bases to methylation and their repair by cellular defense systems. Among the lesions in methylated DNA is 1meA/3meC, which is recently recognized as being mutagenic. In this report, special attention is focused on the mutagenic properties of 1meA/3meC which, by the activity of AlkB-dioxygenase, are quickly and efficiently converted to natural A/C bases in the DNA of E. coli alkB(+) strains, preventing 1meA/3meC-induced mutations. We have found that in the absence of AlkB-mediated repair, MMS treatment results in an increased frequency of four types of base substitutions: GC-->CG, GC-->TA, AT-->CG, and AT-->TA, whereas overproduction of PolV in CC101-106 alkB(-)/pRW134 strains leads to a markedly elevated level of GC-->TA, GC-->CG, and AT-->TA transversions. It has been observed that in the case of AB1157 alkB(-) strains, the MMS-induced and 1meA/3meC-dependent argE3-->Arg(+) reversion occurs efficiently, whereas lacZ(-)--> Lac(+) reversion in a set of CC101-106 alkB(-) strains occurs with much lower frequency. We considered several reasons for this discrepancy, namely, the possible variance in the level of the PolV activity, the effect of the PolIV contents that is higher in CC101-106 than in AB1157 strains and the different genetic cell backgrounds in CC101-106 alkB(-) and AB1157 alkB(-) strains, respectively. We postulate that the difference in the number of targets undergoing mutation and different reactivity of MMS with ssDNA and dsDNA are responsible for the high (argE3-->Arg(+)) and low (lacZ(-) --> Lac(+)) frequency of MMS-induced mutations.

Evaluación de las Propiedades Mecánicas de una Mezcla Densa en Caliente Modificada con un Desecho de PVC

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Hugo A. Rondón-Quintana

2011-12-01

Full Text Available El presente trabajo evaluó en laboratorio, la resistencia mecánica bajo carga monotónica, el módulo resiliente y la resistencia a la deformación permanente que experimenta una mezcla asfáltica cuando se modifica con un desecho de policloruro de vinilo (PVC por vía húmeda. Adicionalmente, fue evaluada durante 21 meses, la influencia del medio ambiente de la ciudad de Bogotá D.C. sobre las propiedades mecánicas de la mezcla modificada. De los resultados obtenidos se concluye que la resistencia mecánica de la mezcla asfáltica modificada es superior en comparación con la convencional. La tendencia general de las mezclas con el tiempo de exposición al medio ambiente de Bogotá D.C. es experimentar un aumento en los valores de rigidez debido principalmente a procesos de endurecimiento por envejecimiento del ligante asfáltico. Sin embargo, para el caso de las mezclas fabricadas con CA 60-70 y modificadas con PVC en los primeros 15 meses de exposición, la rigidez disminuye por efecto de micro-fisuración térmica.

Molecular characterization of resistance to Rifampicin in an emerging hospital-associated Methicillin-resistant Staphylococcus aureus clone ST228, Spain

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Liñares Josefina

2010-03-01

Full Text Available Abstract Background Methicillin-resistant S. aureus (MRSA has been endemic in Hospital Universitari de Bellvitge, Barcelona, since 1990. During the 1990-95 period the Iberian clone (ST-247; SCCmec-I was dominant. Isolates of clonal complex 5 (ST-125; SCCmec-IV gradually replaced the Iberian clone from 1996 to 2003. A new multiresistant MRSA phenotype showing rifampicin resistance emerged in 2004 and rapidly increased from 25% in 2004 to 45% in 2006. The aims of this study were i the molecular characterisation of rifampicin resistant MRSA isolates, ii the study of the rifampicin resistance expression by disk diffusion, microdilution and E-test, and iii the analysis of the rpoB gene mutations involved in rifampicin resistance. Results A sample of representative 108 rifampicin-resistant MRSA isolates belonged to a single PFGE genotype, ST-228, SCCmec type I and spa type t041. Of 108 isolates, 104 (96% had a low-level rifampicin resistance (MICs, 2 to 4 mg/L and 4 a high-level rifampicin resistance (MICs, 128 - ≥ 256 mg/L. Disk diffusion and E-test methods failed to identify a low-level rifampicin resistance in 20 and 12 isolates, respectively. A low-level rifampicin resistance was associated with amino acid substitution 481His/Asn in the beta-subunit of RNA polymerase. Isolates with a high-level rifampicin resistance carried additional mutations in the rpoB gene. Conclusions The emergence of MRSA clone ST228-SCCmecI, related to the Southern Germany clone, involved a therapeutical challenge for treating serious MRSA infections. Decreased susceptibility to rifampicin in MRSA strains of ST228-SCCmecI was associated with one or two specific mutations in the rpoB gene. One fifth of isolates with low-level rifampicin-resistance were missed by the diffusion methods.

Evaluación del dolor en pacientes sometidos a ventilación mecánica invasiva ingresados en las unidades de cuidados intensivos

OpenAIRE

Ferreras Llamazares, Cristina

2012-01-01

Introducción. La valoración del dolor presenta especial dificultad en pacientes críticos, en concreto en pacientes sometidos a ventilación mecánica invasiva, ya que no pueden comunicar este dolor. Objetivos. • Conocer en los enfermeros, el grado de conocimientos y la utilización de escalas del dolor en pacientes sometidos a ventilación mecánica. • Conocer la prevalencia, grado de dolor y las respuestas fisiológicas de los pacientes, antes, durante y después del cambio postural reali...

Meson exchange current (MEC) models in neutrino interaction generators

International Nuclear Information System (INIS)

Katori, Teppei

2015-01-01

Understanding of the so-called 2 particle-2 hole (2p-2h) effect is an urgent program in neutrino interaction physics for current and future oscillation experiments. Such processes are believed to be responsible for the event excesses observed by recent neutrino experiments. The 2p-2h effect is dominated by the meson exchange current (MEC), and is accompanied by a 2-nucleon emission from the primary vertex, instead of a single nucleon emission from the charged-current quasi-elastic (CCQE) interaction. Current and future high resolution experiments can potentially nail down this effect. For this reason, there are world wide efforts to model and implement this process in neutrino interaction simulations. In these proceedings, I would like to describe how this channel is modeled in neutrino interaction generators

Influencia del enfriamiento de la etapa de cocción sobre las propiedades mecánicas del gres porcelánico

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de Noni Junior, A.

2007-08-01

Full Text Available This study was undertaken to determine the influence of post-fire cooling on generation of residual stress and mechanical properties in porcelain tile. The test pieces were prepared and subjected to different types of cooling. Macroscopic stresses were determined by the strain relaxation method with incremental cutting. Microscopic stresses on the quartz particles were analysed by X-ray diffraction (XRD. During fast cooling, a macroscopic residual stress profile, characteristic of tempering processes in glasses, was observed to develop with the ensuing increase in mechanical strength. XRD analysis showed that the quartz particles were subjected to tension, additionally strengthening the material. However, the quartz also gave rise to microstructural deterioration owing to crack generation and growth. Such microstructural deterioration limits the increase in mechanical strength, in particular for the high cooling rates used after the allotropic transformation of quartz.

El presente estudio ha sido planteado con el objeto de determinar la influencia del enfriamiento de la etapa de cocción sobre el desarrollo de tensiones residuales y las propiedades mecánicas del gres porcelánico. Para ello se prepararon probetas que fueron sometidas a diferentes tipos de enfriamiento. Las tensiones macroscópicas fueron determinadas con el método de relajación de deformaciones por corte incremental. Las tensiones microscópicas sobre las partículas de cuarzo fueron analizadas por DRX. Se observó que durante el enfriamiento rápido el material desarrolla un perfil de tensiones residuales macroscópicas característico de procesos de templado de vidrios, con el consecuente incremento en la resistencia mecánica. La difracción de rayos X ha puesto de manifiesto que las partículas de cuarzo se encuentran sometidas a tracción, reforzando también el material. Sin embargo, el cuarzo provoca un deterioro microestructural por la generación y crecimiento

Esfera em plano inclinado: conservação da energia mecânica e força de atrito

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Silva Wilton Pereira da

2003-01-01

Full Text Available Este artigo propõe um experimento visando demonstrar que a força de atrito estático é conservativa. O experimento consiste em uma esfera rolando em um plano inclinado. para o qual a inclinação pode ser variada. Para cada ângulo estabelecido a energia mecânica no início e no fim da pista foi determinada. A análise dos resultados mostrou que a conservação da energia mecânica ocorre até um ângulo limite, a partir do qual há escorregamento. A determinação deste ângulo por inspeção gráfica possibilitou o cálculo do coeficiente de atrito estático entre a pista e a esfera em movimento.

Relación entre la presión inspiratoria pico y la activación mecánica de los músculos inspiratorios durante respiración tranquila en pacientes con EPOC

OpenAIRE

Sarlabous Uranga, Leonardo; Torres Cebrián, Abel; Fiz Fernández, José Antonio; Gea Guiral, Joaquim; Martínez Llorens, Juana María; Jané Campos, Raimon

2014-01-01

En la enfermedad pulmonar obstructiva crónica (EPOC) la fuerza muscular inspiratoria (FMI) y la eficiencia mecánica de los músculos inspiratorios (EMMI) podrían verse reducidas como consecuencia de la hiperinsuflación. En este trabajo se registraron la presión inspiratoria en boca (PIpico) y la activación mecánica de los músculos inspiratorios en 10 pacientes EPOC severos y muy severos, durante respiración tranquila. Para determinar la activación mecánica de los músculos inspiratorios se empl...

Comportamiento mecánico de la aleación AZ31 reforzada con nanofibras de carbono

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Adeva, P.

2010-12-01

Full Text Available The aim of this study is to investigate the effect of reinforcing AZ31 with carbon nanofibres. The materials AZ31, AZ31-1 % C y AZ31-2 % C were produced by a conventional powder metallurgy route consisting of mechanical mixing of nanofibres and powders of AZ31, cool compactation and extrusion at 350 °C. After extrusion the three materials exhibited a recrystallized microstructure of similar grain size, fine and rather inhomogeneous. Furthermore, they presented a weak fibre texture with basal plane parallel to the extrusion direction. The tensile properties were affected by the nanofibres presence only at 100 °C. At this temperature, yield strength and tensile strength were 30% higher than in the unreinforced alloy.

En este trabajo se ha estudiado el efecto de la adición de nanofibras de carbono en las propiedades mecánicas de la aleación AZ31 procesada por una ruta pulvimetalúrgica convencional. Se prepararon tres materiales, AZ31, AZ31- 1 % C y AZ31-2 % C. Tras una mezcla mecánica de las nanofibras con los polvos de AZ31, se precompactaron en frío y se extruyeron a 350 °C. Los tres presentan una microestructura recristalizada con un tamaño de grano similar, fino aunque algo heterogéneo. Los tres materiales presentan una débil textura de fibra con el plano basal paralelo a la dirección de extrusión. Las propiedades mecánicas a tracción únicamente se ven afectadas por la presencia de nanofibras a 100 °C superando los materiales reforzados en un 30 % a los valores de límite elástico y resistencia de la aleación sin reforzar.

Identification of Methicillin-Resistant Staphylococcus aureus (MRSA) Using Simultaneous Detection of mecA, nuc, and femB by Loop-Mediated Isothermal Amplification (LAMP).

Science.gov (United States)

Chen, Changguo; Zhao, Qiangyuan; Guo, Jianwei; Li, Yanjun; Chen, Qiuyuan

2017-08-01

The aim of this study was to develop a rapid detection assay to identify methicillin-resistant Staphylococcus aureus by simultaneous testing for the mecA, nuc, and femB genes using the loop-mediated isothermal amplification (LAMP) method. LAMP primers were designed using online bio-software ( http://primerexplorer.jp/e/ ), and amplification reactions were performed in an isothermal temperature bath. The products were then examined using 2% agarose gel electrophoresis. MecA, nuc, and femB were confirmed by triplex TaqMan real-time PCR. For better naked-eye inspection of the reaction result, hydroxy naphthol blue (HNB) was added to the amplification system. Within 60 min, LAMP successfully amplified the genes of interest under isothermal conditions at 63 °C. The results of 2% gel electrophoresis indicated that when the Mg 2+ concentration in the reaction system was 6 μmol, the amplification of the mecA gene was relatively good, while the amplification of the nuc and femB genes was better at an Mg 2+ concentration of 8 μmol. Obvious color differences were observed by adding 1 μL (3.75 mM) of HNB into 25 μL reaction system. The LAMP assay was applied to 128 isolates cases of methicillin-resistant Staphylococcus aureus, which were separated from the daily specimens and identified by Vitek microbial identification instruments. The results were identical for both LAMP and PCR. LAMP offers an alternative detection assay for mecA, nuc, and femB and is faster than other methods.

A importância da pressão pleural na avaliação da mecânica respiratória

OpenAIRE

Fernandes,Cláudia Regina

2006-01-01

JUSTIFICATIVA E OBJETIVOS: Para a partição das medidas de mecânica do sistema respiratório em seus componentes pulmão e parede torácica, faz-se necessário o conhecimento da pressão pleural. A finalidade desta revisão foi discutir sobre medidas alternativas à obtenção da pressão pleural para o cálculo da mecânica pulmonar, relatar as peculiaridades do método do balão esofágico para obtenção indireta da pressão pleural, as particularidades da obtenção da medida da pressão esofágica em pacientes...

Caracterización de las propiedades mecánicas y microestructurales de soldaduras empleadas en la recuperación de ejes

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César Cerón Bolaños

2006-01-01

Full Text Available Se analizaron las propiedades mecánicas y las características microestructurales de los materiales de aporte y la zona afectada térmicamente (ZAT de tres procedimientos de soldadura de arco eléctrico, usados para la recuperación de ejes desgastados de molinos de caña de azúcar. En dos procedimientos se identificó que en la ZAT había ferrita en bordes de grano, mayor crecimiento de grano y la estructura Widmanstaetten, lo cual reduce la tenacidad del acero. Las soldaduras se compararon partiendo de sus propiedades mecánicas por medio de ensayos de tensión y de impacto Charpy.

[Spread of genetically related methicillin-susceptible Staphylococcus aureus belonging to CC45, in healthy nasal carriers in Child Day Care Centers of Medellin, Colombia].

Science.gov (United States)

Rodríguez-Tamayo, Erika Andrea; Ruiz-Cadavid, Alejandra; Sánchez-González, Leidy Maritza; García-Valencia, Natalia; Jiménez-Quiceno, Judy Natalia

2016-03-01

Colonization plays a major role in the epidemiology and pathogenesis of Staphylococcus aureus infections. The child population is one of the most susceptible to colonization; however, community and children studies are limited in Colombia. To assess the clonal relationship of S.aureus strains isolated from colonized children in eight day care centers (DCCs) from Medellin and to determine the presence of epidemiological characteristics in these populations. An observational cross-sectional study was conducted on a sample of 200 children aged from 6 months to 5 years attending eight DCCs in Medellin, Colombia, during 2011. Nasal samples were collected from each nostril. The isolates species and methicillin resistance were molecularly confirmed using nuc and mec genes. Genotypic analysis included SCCmec typing, spa typing, PFGE and MLST. Epidemiological information was obtained from the parents and analyzed using the statistics program SPSS 21.0 RESULTS: The colonization frequency in DCCs ranged from 16.7% (n=3) to 53.6% (n=15). Genetically related isolates were identified inside four DCCs. Half (50%) of the isolates were grouped in 3 clusters, which belonged to the clonal complexes CC45, CC30, and CC121. Molecular typing of isolates from colonized children and comparison among DCCs showed the spread of colonizing strains inside DCCs in Medellin; predominantly the CC45 clone, a successful child colonizer. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Zinc Resistance within Swine-Associated Methicillin-Resistant Staphylococcus aureus Isolates in the United States Is Associated with Multilocus Sequence Type Lineage.

Science.gov (United States)

Hau, Samantha J; Frana, Timothy; Sun, Jisun; Davies, Peter R; Nicholson, Tracy L

2017-08-01

Zinc resistance in livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) sequence type 398 (ST398) is primarily mediated by the czrC gene colocated with the mecA gene, encoding methicillin resistance, within the type V staphylococcal cassette chromosome mec (SCC mec ) element. Because czrC and mecA are located within the same mobile genetic element, it has been suggested that the use of zinc in feed as an antidiarrheal agent has the potential to contribute to the emergence and spread of methicillin-resistant S. aureus (MRSA) in swine, through increased selection pressure to maintain the SCC mec element in isolates obtained from pigs. In this study, we report the prevalence of the czrC gene and phenotypic zinc resistance in U.S. swine-associated LA-MRSA ST5 isolates, MRSA ST5 isolates from humans with no swine contact, and U.S. swine-associated LA-MRSA ST398 isolates. We demonstrated that the prevalence of zinc resistance in U.S. swine-associated LA-MRSA ST5 isolates was significantly lower than the prevalence of zinc resistance in MRSA ST5 isolates from humans with no swine contact and swine-associated LA-MRSA ST398 isolates, as well as prevalences from previous reports describing zinc resistance in other LA-MRSA ST398 isolates. Collectively, our data suggest that selection pressure associated with zinc supplementation in feed is unlikely to have played a significant role in the emergence of LA-MRSA ST5 in the U.S. swine population. Additionally, our data indicate that zinc resistance is associated with the multilocus sequence type lineage, suggesting a potential link between the genetic lineage and the carriage of resistance determinants. IMPORTANCE Our data suggest that coselection thought to be associated with the use of zinc in feed as an antimicrobial agent is not playing a role in the emergence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) ST5 in the U.S. swine population. Additionally, our data indicate

Efeitos do treinamento físico sobre a resistência mecânica do terço proximal do fêmur de ratos

OpenAIRE

Aguiar,Andreo Fernando; Agati,Leandro Barile; Müller,Sérgio Swain; Pereira,Oduvaldo Camara; Dal-Pai-Silva,Maeli

2010-01-01

OBJETIVO: Analisar o comportamento mecânico do terço proximal do fêmur de ratos submetidos ao treinamento aeróbio e resistido crônicos. MÉTODOS: Ratos Wistar machos (80 dias, 300 a 350 g) foram divididos em 3 grupos (n=8 por grupo): Treinamento aeróbio/8 semanas (TA), Treinamento resistido/8 semanas (TR) e controle/8 semanas (CO). Ao término do período de treinamento os animais foram sacrificados e o fêmur direito coletado. Para análise do comportamento mecânico do fêmur foram realizados ensa...

Characterisation of methicillin-resistant Staphylococcus aureus clinical isolates from animals in New Zealand, 2012-2013, and subclinical colonisation in dogs and cats in Auckland.

Science.gov (United States)

Karkaba, A; Benschop, J; Hill, K E; Grinberg, A

2017-03-01

To characterise methicillin-resistant Staphylococcus aureus (MRSA) isolates from infection sites in animals in New Zealand and assess the prevalence of subclinical MRSA colonisation in dogs and cats attending veterinary clinics in Auckland. MRSA isolates from clinical specimens obtained by the main New Zealand veterinary diagnostic laboratories between June 2012 and June 2013, were genotypically characterised by DNA microarray hybridisation analysis and spa typing. In addition, nasal or perineal skin swabs collected from a cross-sectional sample of dogs (n=361) and cats (n=225) attending 29 veterinary clinics in Auckland during the same period were analysed for MRSA by culture. Eight MRSA clinical isolates were submitted for characterisation by the participating laboratories. The isolates originated from five dogs, including two isolates from the same dog, one foal, and one isolate had no identification of the source. The strain-types identified were AK3 (ST-5 SCCmecIV t045; n=1), USA500 (ST8 SCCmecIV t064; n=1), WSPP (ST30 SCCmecIV t019; n=1), Rhine Hesse (ST5 SCCmecII t002; n=2), and EMRSA-15 (ST22 SCCmecIV t032; n=3). No MRSA were isolated from 586 cultured swabs. Methicillin-susceptible S. aureus were detected in 9/257 (3.5%) swabs and non-aureus staphylococci in 22/257 (8.5%) swabs. The estimated true MRSA subclinical colonisation prevalence was 0%, with an upper 95% CI boundary of 1.9% for cats and 1.4% for dogs. The modest number of MRSA isolates submitted for this study by the participating laboratories suggests clinical MRSA infection in animals in New Zealand continues to be sporadic. The wide variety of strain-types found mirrored the evolving strain-type diversity observed in humans. We cannot rule out bias due to the non-random sampling of dogs and cats, but the apparent colonisation prevalence of 0% was consistent with the low prevalence of subclinical colonisation in humans in New Zealand. These similarities indicate the epidemiology of animal and

Relación microestructura - comportamiento mecánico en estructuras bainíticas

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Altuna, M. A.

2005-10-01

Full Text Available In the present work, the microestructures and their mechanical properties have been studied in different bainitic structures. Therefore, different bainitic morphologies have been produced by isothermal treatments carried out at different temperatures. For these steels, 400-450 °C is the optimum range of temperatures in order to obtain bainitic structures. If the Temperature is higher, perlite is also formed and if it is lower, martensite is obtained during quenching. SEM and EBSD/OIM techniques were applied in order to study the microstructure. Tensile tests were carried out for mechanical characterization.

En el presente trabajo, se ha estudiado la microestructura de distintos tipos de estructuras bainíticas y las correspondientes propiedades mecánicas. Con el fin de generar diferentes microestructuras de tipo bainítico se han realizado tratamientos térmicos a distintas temperaturas. Para los aceros analizados, se ha obtenido que el rango óptimo, a la hora de obtener estructuras baíniticas, es aproximadamente 400-450 °C. Si la temperatura de tratamiento es más alta, se favorece la formación de perlita y, en cambio, si la temperatura es más baja, tiene lugar la formación de martensita durante el temple final. La microestructura se ha analizado mediante SEM y EBSD/OIM. La caracterización mecánica de los aceros sé ha llevado a cabo mediante ensayos de tracción.

Técnicas de indentación: medición de propiedades mecánicas en cerámicas

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JUAN MANUEL MEZA

2006-01-01

Full Text Available Las técnicas de indentación poseen una gran versatilidad que permite evaluar propiedades mecánicas en volúmenes inferiores a 0.001 mm3, hasta volúmenes del orden de los mm3, útil tanto en materiales compuestos como en volumen. Este artículo hace una revisión general de los fundamentos de éstas técnicas. También se muestran algunas de las dificultades que surgen cuando éstas son aplicadas a la medición de propiedades mecánicas de materiales cerámicos, tales como su dureza tenacidad a la fractura, módulo de elasticidad y adherencia de capas cerámicas en sustratos metálicos. Para esto se utilizan algunos materiales cerámicos en volumen como alúmina Al2O3, Titanato de Bario BaTiO3 y capas TiN depositadas sobre acero M2.

Vivenciando o contato pele a pele com o recém-nascido no pós-parto como um ato mecânico

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Luciano Marques dos Santos

2014-04-01

Full Text Available Objetivou-se compreender a vivência da puérpera durante o primeiro contato pele a pele com o recém-nascido no pós-parto imediato, no centro obstétrico de um hospital público de uma cidade no interior da Bahia. Estudo exploratório, descritivo e qualitativo, aprovado por Comitê de Ética e realizado com quatorze puérperas, através de entrevistas semiestruturadas, no período de julho a agosto de 2011. Os dados foram analisados por meio da Teoria Fundamentada nos Dados, identificando-se o fenômeno "Vivenciando o contato pele a pele como um ato mecânico" e suas três subcategorias "Incentivando só o contato", "O contato como um ato mecânico" e "Sendo obrigada a iniciar o aleitamento materno". O incentivo do contato pele a pele e aleitamento imediatos ocorrem de forma mecânica, sendo destacado só o contato, obrigando a puérpera a iniciar o aleitamento materno de forma brusca e repentina, não sendo respeitada sua vontade de executar ou não essa prática.

Propriedades mecânicas da madeira resinada de Pinus elliottii

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André Luiz Missio

2015-08-01

Full Text Available As propriedades mecânicas por flexão estática da madeira resinada de Pinus elliottii foram avaliadas por meio de testes destrutivos e não destrutivos. Para tanto, foram confeccionados corpos de prova de 10x10x200mm3 (radial, tangencial e longitudinal, levando em consideração dois fatores: lenho (juvenil, próximo à medula e adulto, próximo à casca e resina, isto é, corpos de prova oriundos de toras com e sem estrias de resinagem. Para a avaliação não destrutiva, utilizou-se um aparelho de ultrassom com transdutores do tipo ponto seco, em que se pode calcular a velocidade da onda ultrassônica e consequentemente o módulo de elasticidade dinâmico (ED. Para obtenção do módulo de elasticidade (MOE e do módulo de ruptura (MOR, realizou-se o ensaio destrutivo de flexão estática de três pontos. De posse das curvas de força x deformação, calculou-se a fragilidade do material. Os resultados confirmaram que o fator lenho foi significativo para as propriedades analisadas e o fator resina, em especial, para aumento do MOR e da massa específica. A fragilidade aumentou quando analisada a madeira juvenil e o fator resina quando incluso tendeu a aumentar a fragilidade no lenho adulto. O modelo de regressão múltiplo com variáveis Dummies, proposto para estimar o MOE pelo ED, foi significativo em 1% de probabilidade de erro (r2=0,75. Os resultados apresentados no presente trabalho mostraram que os fatores lenho e resina não afetaram negativamente as propriedades mecânicas da madeira de Pinus elliottii, em que, para o segundo fator, conclui-se, de maneira geral, que a madeira serrada oriunda de toras resinadas pode não representar danos significativos quando em serviço estrutural

Eficacia de métodos químicos, físicos y mecánicos en la limpieza de costras y grafitis en granito

OpenAIRE

Pozo Antonio, Jose Santiago

2013-01-01

[spa] En esta tesis doctoral “Eficacia de métodos químicos, físicos y mecánicos en la limpieza de costras y grafitis en granito” se realiza la evaluación de la eficacia y efectos nocivos de diferentes métodos de limpieza aplicados con el objeto de extraer costras negras biológicas, costras negras sulfatadas y grafitis en granito. Los métodos evaluados son de tipo químico (productos químicos aplicados de manera directa o mezclados con espesantes), mecánicos (abrasivo a baja pres...

Caracterização mecânica de toros de madeira lamelada colada

OpenAIRE

Branco, Jorge M.; Cruz, Paulo J. S.

2009-01-01

Neste trabalho descreve-se a caracterização mecânica de toros de madeira lamelada colada pertencentes a um sistema construtivo de casas pré-fabricadas de madeira. Os módulos de elasticidade global e local à flexão, à compressão paralela e perpendicular às fibras, bem como os valores das respectivas tensões resistentes, foram obtidos de acordo com a norma Europeia EN 408:2003. Na análise destas propriedades foi tida em conta a influência do número de lamelas, ao considerar-se pa...

Efeitos da tosse manualmente assistida sobre a mecânica do sistema respiratório de pacientes em suporte ventilatório total

OpenAIRE

Avena,Katia de Miranda; Duarte,Antonio Carlos Magalhães; Cravo,Sergio Luiz Domingues; Sologuren,Maria José Junho; Gastaldi,Ada Clarice

2008-01-01

OBJETIVO: A tosse manualmente assistida (TMA) consiste na compressão vigorosa do tórax no início da expiração espontânea ou da fase expiratória da ventilação mecânica. Tendo em vista a utilização rotineira da TMA na unidade de terapia intensiva, a proposta deste estudo foi analisar os efeitos dessa técnica no comportamento da mecânica do sistema respiratório de pacientes submetidos a suporte ventilatório total. MÉTODOS: Foram estudados 16 pacientes intubados, sedados e submetidos à ventilação...

Detection and Characterization of Staphylococcus aureus and Methicillin-Resistant S. aureus in Foods Confiscated in EU Borders

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David Rodríguez-Lázaro

2017-07-01

Full Text Available The aim of the study was to evaluate the potential role of the illegal entry of food in UE in the Methicillin-resistant S. aureus (MRSA spread. We studied the prevalence and characteristics of Staphylococcus aureus and MRSA isolated from foods of animal origin confiscated from passengers on flights from 45 non-EU countries from 2012 to 2015 by the Border Authorities at Bilbao International Airport (Spain and Vienna International Airport (Austria, as well as foods from open markets close to EU land borders. Of 868 food samples tested (diverse meat samples including antelope, duck, guinea pig, pork, rodents, turkey, dairy products, and eggs, 136 (15.7% were positive for S. aureus and 26 (3.0% for MRSA. All MRSA strains were mecA-positive. The prevalence of S. aureus-positive dairy samples among food confiscated at Bilbao International Airport was 64.6%, and this airport also had the highest value (11.8% for MRSA-positive samples. The predominant sequence type was ST5 (30.8%, followed by ST8, ST1649, ST1, and other lineages were found to a lesser extent (ST7, ST22, ST72, ST97, and ST398. Six isolates tested positive for luk-PVL genes (SCCmec IV subtypes IVc and IVe. Enterotoxin profiling revealed that 19 MRSA strains were enterotoxigenic, harboring one or more se genes. The MRSA isolates positive for luk-PVL genes were not enterotoxigenic, and none of the isolates tested positive for enterotoxin E. We found 14 resistance profiles, and more than 69% of the MRSA isolates were resistant to three or more types of antimicrobial agents. This finding reveals both the wide diversity of the antimicrobial resistance found in the strains and the capacity to resist not only to beta-lactam drugs. One MRSA strain showed unusual characteristics: it was oxacillin-susceptible, harbored SCCmec V, and was positive for sed, seg, and sej but negative for PVL virulence factors. This study shows the presence of enterotoxigenic HA-, CA-, and LA-MRSA in foods illegally

Interaction of humic acids and humic-acid-like polymers with herpes simplex virus type 1

Science.gov (United States)

Klöcking, Renate; Helbig, Björn

The study was performed in order to compare the antiviral activity against herpes simplex virus type 1 (HSV-1) of synthetic humic-acid-like polymers to that of their low-molecular-weight basic compounds and naturally occurring humic acids (HA) in vitro. HA from peat water showed a moderate antiviral activity at a minimum effective concentration (MEC) of 20 µg/ml. HA-like polymers, i.e. the oxidation products of caffeic acid (KOP), hydrocaffeic acid (HYKOP), chlorogenic acid (CHOP), 3,4-dihydroxyphenylacetic acid (3,4-DHPOP), nordihydroguaretic acid (NOROP), gentisinic acid (GENOP), pyrogallol (PYROP) and gallic acid (GALOP), generally inhibit virus multiplication, although with different potency and selectivity. Of the substances tested, GENOP, KOP, 3,4-DHPOP and HYKOP with MEC values in the range of 2 to 10 µg/ml, proved to be the most potent HSV-1 inhibitors. Despite its lower antiviral potency (MEC 40 µg/ml), CHOP has a remarkable selectivity due to the high concentration of this polymer that is tolerated by the host cells (>640 µg/ml). As a rule, the antiviral activity of the synthetic compounds was restricted to the polymers and was not preformed in the low-molecular-weight basic compounds. This finding speaks in favour of the formation of antivirally active structures during the oxidative polymerization of phenolic compounds and, indirectly, of corresponding structural parts in different HA-type substances.

Caracterización del gen mecA de Staphylococcus aureus resistentes a meticilina aislados de tres grupos poblacionales de la ciudad de Medellín

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Marcela Sanchez

Full Text Available Introducción: Staphylococcus aureus resistente a la meticilina (SARM es responsable de infecciones intrahospitalarias, las que constituyen una importante causa de morbilidad y mortalidad en nuestro medio, por lo cual la rápida identificación y tipificación molecular de la resistencia como el complejo SSCmec es esencial para entender la epidemiología de la infección. Objetivo: Caracterizar fenotípicamente la resistencia a meticilina y genotípicamente el casete cromosomal SSCmec en cepas de S. aureus aislados de individuos de la ciudad de Medellín mediante PCR múltiple. Materiales y métodos: A 41 aislamientos (hospitalarios y de la comunidad de S. aureus se les estableció la resistencia a cefoxitin mediante la técnica de Kirby-Bauer y la concentración inhibitoria mínima para oxacilina. Mediante PCR convencional se les confirmó la presencia del gen mecA. Para la tipificación del complejo SSCmec se utilizó PCR múltiple para amplificar 6 loci diferentes de este gen. Resultados: A todos los aislamientos se les confirmó resistencia a meticilina y la presencia del gen mecA, de los cuales 17 fueron clasificados como SSC mec I, 1 como SSC mec II, 21 como SSC mecIV; dos aislamientos no fue posible clasificarlos. Conclusiones: Con el uso de esta técnica clasificamos el 95% de los aislamientos del estudio, encontrando una mayor prevalencia de los SSCmec I y IV. La implementación de esta técnica permite una fácil caracterización de los aislamientos SARM y un apropiado manejo de la información de los integrantes de los comités de infecciones hospitalarios, lo cual podría impactar positivamente en el tratamiento a los pacientes y el control de enfermedades infecciosas intrahospitalarias.

Defects in the medial entorhinal cortex and dentate gyrus in the mouse model of Sanfilippo syndrome type B.

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Kazuhiro Ohmi

Full Text Available Sanfilippo syndrome type B (MPS IIIB is characterized by profound mental retardation in childhood, dementia and death in late adolescence; it is caused by deficiency of α-N-acetylglucosaminidase and resulting lysosomal storage of heparan sulfate. A mouse model, generated by homologous recombination of the Naglu gene, was used to study pathological changes in the brain. We found earlier that neurons in the medial entorhinal cortex (MEC and the dentate gyrus showed a number of secondary defects, including the presence of hyperphosphorylated tau (Ptau detected with antibodies raised against Ptau in Alzheimer disease brain. By further use of immunohistochemistry, we now show staining in neurons of the same area for beta amyloid, extending the resemblance to Alzheimer disease. Ptau inclusions in the dentate gyrus of MPS IIIB mice were reduced in number when the mice were administered LiCl, a specific inhibitor of Gsk3β. Additional proteins found elevated in MEC include proteins involved in autophagy and the heparan sulfate proteoglycans, glypicans 1 and 5, the latter closely related to the primary defect. The level of secondary accumulations was associated with elevation of glypican, as seen by comparing brains of mice at different ages or with different mucopolysaccharide storage diseases. The MEC of an MPS IIIA mouse had the same intense immunostaining for glypican 1 and other markers as MPS IIIB, while MEC of MPS I and MPS II mice had weak staining, and MEC of an MPS VI mouse had no staining at all for the same proteins. A considerable amount of glypican was found in MEC of MPS IIIB mice outside of lysosomes. We propose that it is the extralysosomal glypican that would be harmful to neurons, because its heparan sulfate branches could potentiate the formation of Ptau and beta amyloid aggregates, which would be toxic as well as difficult to degrade.

Condiciones de seguridad en el trabajo relacionadas con la exposición a peligro mecánico en una empresa de logística - Bogotá 2013

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Jhon Jairo Beltrán Molina

2015-08-01

Full Text Available Introducción: En una empresa de logística se evidencian peligros mecánicos relacionados con el uso de máquinas y herramientas, que puede generar accidentes trabajo. Objetivo: Caracterizar y evaluar las condiciones de seguridad en el trabajo relacionadas con la manipulación de máquinas y herramientas, el movimiento manual de objetos y el movimiento mecánico de materiales. Materiales y métodos: Estudio cualitativo descriptivo de corte transversal. Se utilizó la regional Bogotá de la empresa internacional. Se seleccionaron los procesos críticos en manipulación de máquinas, uso de herramientas, manipulación manual de objetos y transporte mecánico de materiales. La muestra se determinó por muestreo aleatorio simple. Se aplicó un Instrumento con 61 preguntas a trabajadores y 4 listas de chequeo a maquinaria. El procesamiento se realizó en una hoja de cálculo y su análisis mediante estadística descriptiva. Resultados: Los empleados tienen un buen nivel de conocimientos. Los trabajadores no se comportan frente al peligro mecánico de manera coherente a sus conocimientos. El grado de peligrosidad de su actividad está relacionado con la exposición a peligro mecánico. El nivel de conocimiento de las normas de seguridad no tiene variación por el tiempo de experiencia o por nivel de escolaridad, mientras que la valoración del grado de peligrosidad sí. Se evidencia controles con cumplimientos parciales. Conclusiones: La empresa tiene controles frente a las condiciones de seguridad que garantizan la protección de los trabajadores, pero es necesario incluir sistemas que minimicen los riesgos. Es importante establecer en el trabajador la cultura de auto cuidado.

Molecular epidemiology of Staphylococcus spp. contamination in the ward environment: study on mecA and femA genes in methicillin-resistant strains.

Science.gov (United States)

Ashimoto, A; Hamada, T; Adachi, A; Tanigawa, T; Tanaka, Y

1995-01-01

Staphylococcus spp. were isolated from the ward environment and antibiotic susceptibility tests were performed. Twenty-nine strains out of 274 isolates were S. aureus, and 41.4% of the S. aureus strains were methicillin resistant (MRSA). All 12 strains of MRSA were also resistant to oxacillin, ceftizoxime, ampicillin and clindamycin. Among the coagulase-negative staphylococci (CNS), methicillin-resistant (MR) strains of S. epidermidis, S. capitis, S. warneri, S. haemolyticus, S. hominis, S. auricularis, S. saprophyticus and S. cohnii were isolated. Eight of the 10 S. Haemolyticus strains were methicillin resistant. The femA gene was detected in S. aureus (MSSA and MRSA), but not in CNS by polymerase chain reaction (PCR) analysis and Southern blot analysis. The mecA gene was found in all the MRSA and MR-S. epidermidis strains tested, and one of the two MR-S. hominis strains, but not in MSSA, MS-S. epidermidis, MS-S. hominis, or MS-S. haemolyticus. DNA from one strain of MR-S. hominis and 2 strains of MR-S. haemolyticus was not amplified by PCR using the mecA gene primer, or hybridized by Southern blotting. The ambiguity that mecA was detected in some MR-CNS strains, but not in others is discussed.

The Plasmin-Sensitive Protein Pls in Methicillin-Resistant Staphylococcus aureus (MRSA Is a Glycoprotein.

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Isabelle Bleiziffer

2017-01-01

Full Text Available Most bacterial glycoproteins identified to date are virulence factors of pathogenic bacteria, i.e. adhesins and invasins. However, the impact of protein glycosylation on the major human pathogen Staphylococcus aureus remains incompletely understood. To study protein glycosylation in staphylococci, we analyzed lysostaphin lysates of methicillin-resistant Staphylococcus aureus (MRSA strains by SDS-PAGE and subsequent periodic acid-Schiff's staining. We detected four (>300, ∼250, ∼165, and ∼120 kDa and two (>300 and ∼175 kDa glycosylated surface proteins with strain COL and strain 1061, respectively. The ∼250, ∼165, and ∼175 kDa proteins were identified as plasmin-sensitive protein (Pls by mass spectrometry. Previously, Pls has been demonstrated to be a virulence factor in a mouse septic arthritis model. The pls gene is encoded by the staphylococcal cassette chromosome (SCCmec type I in MRSA that also encodes the methicillin resistance-conferring mecA and further genes. In a search for glycosyltransferases, we identified two open reading frames encoded downstream of pls on the SCCmec element, which we termed gtfC and gtfD. Expression and deletion analysis revealed that both gtfC and gtfD mediate glycosylation of Pls. Additionally, the recently reported glycosyltransferases SdgA and SdgB are involved in Pls glycosylation. Glycosylation occurs at serine residues in the Pls SD-repeat region and modifying carbohydrates are N-acetylhexosaminyl residues. Functional characterization revealed that Pls can confer increased biofilm formation, which seems to involve two distinct mechanisms. The first mechanism depends on glycosylation of the SD-repeat region by GtfC/GtfD and probably also involves eDNA, while the second seems to be independent of glycosylation as well as eDNA and may involve the centrally located G5 domains. Other previously known Pls properties are not related to the sugar modifications. In conclusion, Pls is a glycoprotein and

Propriedades mecânicas e reológicas de nanocompósitos de poliamida 6 com argila organofílica nacional

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Renê Anisio da Paz

2013-01-01

Full Text Available Nanocompósitos de poliamida 6 com argila organofílica foram preparados pelo método de intercalação no estado fundido. Foram estudadas as propriedades reológicas e mecânicas de nanocompósitos com argila nacional. A argila utilizada foi tratada com o sal quaternário de amônio (Cetremide e foi caracterizada por Espectroscopia no Infravermelho (FTIR e difração de raios X (DRX. Os resultados evidenciaram a incorporação do sal na argila e sua organofilização. Para a obtenção dos nanocompósitos, foram preparados concentrados de PA6/argila (1:1 em (m/m e estes foram adicionados na poliamida 6, em quantidade de 3% de argila no composto final, utilizando uma extrusora de rosca dupla corrotacional. Posteriormente, as amostras foram moldadas por injeção e caracterizadas por: reometria capilar, DRX, MET e ensaios mecânicos (tração e impacto. Os resultados de reometria capilar mostraram que a presença da argila organofílica na PA6 aumentou a viscosidade dos sistemas. Por DRX e MET, foi verificado que todos os sistemas apresentaram predominância de estrutura esfoliada. As propriedades mecânicas sob tração foram melhores do que as da poliamida 6.

Cloning and occurrence of czrC, a gene conferring cadmium and zinc resistance in MRSA CC398 Isolates

DEFF Research Database (Denmark)

Cavaco, Lina; Hasman, Henrik; Stegger, Marc

2010-01-01

the genetic determinant causing zinc resistance in CC398 and examine its prevalence in isolates of animal and human origin. Based on the sequence of the staphylococcal cassette chromosome mec (SCCmec) element from methicillin-resistant S. aureus (MRSA) CC398 strain SO385, a putative metal resistance gene......-four percent (n = 23) of the animal isolates and 48% (n = 24) of the human MRSA isolates of CC398 were resistant to zinc chloride and positive for czrC. All 48 MSSA strains from both human and pig origins were found to be susceptible to zinc chloride and negative for czrC. Our findings showed that czr......C is encoding zinc and cadmium resistance in CC398 MRSA isolates, and that it is widespread both in humans and animals. Thus, resistance to heavy metals such as zinc and cadmium may play a role in the coselection of methicillin resistance in S. aureus....

Typing of Methicillin resistant Staphylococcus aureus: A technical review

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P L Mehndiratta

2012-01-01

Full Text Available Increasing prevalence of Methicillin-resistant Staphylococcus aureus (MRSA worldwide is a growing public health concern. MRSA typing is an essential component of an effective surveillance system to describe epidemiological trends and infection control strategies. Current challenges for MRSA typing are focused on selecting the most appropriate technique in terms of efficiency, reliability, ease of performance and cost involved. This review summarises the available information on application, potential and problems of various typing techniques in discriminating the strains and understanding the epidemiology of MRSA strains. The phenotypic methods in general are easier to perform, easier to interpret, cost effective and are widely available, however less discriminatory. The genotypic methods are expensive and technically demanding, however more discriminatory. Newer technologies involving sequencing of various genes are coming up as broadly applicable and high throughput typing systems. Still there is no consensus regarding the single best method for typing of MRSA strains. Phage typing is recommended as first line approach in epidemiological investigation of MRSA strains. PFGE remains the gold standard for characterisation of outbreak strains. DNA sequencing methods including MLST, spa typing, SCCmec typing and toxin gene profile typing are more practical methods for detecting evolutionary changes and transmission events. The choice of typing technique further depends on the purpose of the study, the facilities available and the utility of data generated to answer a desirable research question. A need for harmonisation of typing techniques by following standard protocols is emphasised to establish surveillance networks and facilitate global MRSA control.

Estudio de las publicaciones periódicas españolas de tecnología e ingeniería mecánica y metalúrgica

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García del Toro, M. A.

1998-03-01

Full Text Available The present article studies the Spanish journals of mechanical and metallurgical technology and engineering, as a first approach to the current state of the main vehicles of diffusion of research in these areas of knowledge in Spain. Their formal features have been analyzed, the types of articles, the origin of contributions, etc. The sources for the analysis of the journals have been the ICYT data base and the original journals. The result is a classification of the Spanish journals of mechanical and metallurgical technology and engineering.

En el presente artículo se ha realizado un estudio de las revistas españolas de tecnología e ingeniería mecánica y metalúrgica, con el objetivo de poder efectuar una primera aproximación al estado actual de los principales órganos de difusión de los avances de la investigación de este grupo de áreas de conocimiento en España. Para ello se ha analizado la presentación de las mismas, los tipos de artículos más frecuentes, la procedencia de las contribuciones, etc. Los instrumentos básicos para el análisis de las revistas han sido la base de datos ICYT y las propias revistas. Como resultado se ofrece una clasificación de las revistas españolas de tecnología e ingeniería mecánica y metalúrgica.

La enseñanza de conceptos fundamentales de Mecánica Cuántica a alumnos de graduación en Física

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Glauco Cohen F. Pantoja

2014-06-01

Full Text Available En este trabajo hemos estudiado la adquisición y retención de conocimiento explícito y las operaciones de pensamiento implícitas en Mecánica Cuántica que han sido hechas por cinco estudiantes de graduación en Física matriculados por primera vez en una asignatura de Mecánica Cuántica. Exponemos los resultados de la implementación de un abordaje didáctico para la enseñanza de conceptos de Sistema Físico, Variables Dinámicas, Estado de un Sistema Físico y Evolución Temporal que hemos delineado para facilitar el aprendizaje significativo, basado en las teorías del aprendizaje de D.P. Ausubel y de G. Vergnaud. Concluimos que hubo evidencias de: cambio considerable de variables de la estructura cognitiva; similitudes (para los conceptos de Sistema Físico y de Variables Dinámicas y diferencias (para los conceptos de Estado y de Evolución Temporal en la adquisición de conceptos por parte de los estudiantes; que cuatro de los cinco estudiantes adoptaran procesos más cercanos del polo significativo que del polo mecánico del aprendizaje; inadecuación del significado atribuido por los estudiantes al concepto de probabilidad, antes, durante y después de la instrucción, lo que muestra una tendencia a ser un obstáculo epistemológico natural que debe ser aclarado con la presentación de situaciones-problema asociadas a la Mecánica Cuántica y que el conocimiento previo tiene un papel crucial en la adquisición,en la retención y en la resolución de problemas, si es tenido en cuenta.

Molecular Typing and Antimicrobial Susceptibility of Methicillin-Resistant Staphylococcus aureus Isolated from Bovine Milk in Tanzania.

Science.gov (United States)

Mohammed, Jibril; Ziwa, Michael Henry; Hounmanou, Yaovi Mahuton Gildas; Kisanga, Adela; Tuntufye, Huruma Nelwike

2018-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) in raw milk can be transmitted from animals to humans, and in Tanzania raw milk is sold in local markets and consumed as purchased. This study was performed to determine the molecular characteristics and antimicrobial susceptibility pattern of MRSA strains isolated from raw bovine milk sold at local markets in Tanzania. A total of 117 raw milk samples were cultured on Baird-Parker medium to isolate S. aureus and PCR was used for amplification of gltB gene for S. aureus identification and the presence of mecA gene for methicillin-resistant strains. Coagulase-negative (CN) S. aureus were reconfirmed using tube coagulase, DNase, and API Staph tests. MRSA isolates were spa typed whereas antimicrobial susceptibility testing was performed by the disc diffusion method. Forty-six coagulase positives (CP) and two CN S. aureus were identified. Most strains were resistant to penicillin (72%), and 3 isolates: 2 CN S. aureus and 1 coagulase-negative Staphylococci (CNS), were phenotypically resistant to vancomycin, oxacillin, and cefoxitin and were confirmed to carry mecA. Resistance to clindamycin, trimethoprim-sulfamethoxazole, and tetracycline was 23.9%, 30.4%, and 41.3%, respectively. Twelve isolates exhibited multidrug resistance; however, only one mecA positive strain among the three was typeable and belonged to spa type t2603. This study reports for the first time the presence of CN variant of MRSA, which was assigned the spa type t2603, and the presence of multidrug resistant S. aureus isolates from bovine milk in Morogoro, Tanzania.

Mass, momentum and energy conserving (MaMEC) discretizations on general grids for the compressible Euler and shallow water equations

NARCIS (Netherlands)

Hof, Bas van ’t; Veldman, Arthur E.P.

2012-01-01

The paper explains a method by which discretizations of the continuity and momentum equations can be designed, such that they can be combined with an equation of state into a discrete energy equation. The resulting 'MaMEC' discretizations conserve mass, momentum as well as energy, although no

Ambientes Virtuales Para la enseñanza de la Mecánica de Fluidos: Algunos ejemplos simplificados aplicando ANSYS

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Watson L. Vargas

2005-01-01

Full Text Available Para que un ambiente de enseñanza virtual pueda soportar un aprendizaje real, dichos ambientes deben proveer interacciones enseñanza-aprendizaje de alto nivel. En este artículo, se muestra como una herramienta computacional como ANSYS puede proveer un ambiente virtual para el aprendizaje de la mecánica de fluidos no sólo a nivel de pregrado si no también a niveles superiores. Las simulaciones computacionales, --aplicando ANSYS/FLOTRAN-CFD o cualquiera otro software de capacidades similares--, en el contexto de la enseñanza de la mecánica de fluidos son de interés fundamental dado que soportan un ambiente de simulación poderoso que puede aplicarse no sólo a la comprensión de ideas y conceptos fundamentales sino tambien al diseño y optimización de procesos de aplicación práctica

Antimicrobial resistance and detection of mecA and blaZ genes in coagulase-negative Staphylococcus isolated from bovine mastitis

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Lidiane C. Soares

2012-08-01

Full Text Available The present study evaluated the pheno- and genotypical antimicrobial resistance profile of coagulase-negative Staphylococcus (CNS species isolated from dairy cows milk, specially concerning to oxacillin. Of 100 CNS isolates, the S. xylosus was the prevalent species, followed by S. cohnii, S. hominis, S. capitis and S. haemolyticus. Only 6% were phenotypically susceptible to the antimicrobial agents tested in disk diffusion assay. Penicillin and ampicillin resistance rates were significantly higher than others antimicrobials. Four isolates were positive to mecA gene (4%, all represented by the S. xylosus species. The blaZ gene was detected in 16% of the isolates (16/100. It was noticed that all mecA + were also positive to this gene and the presence of both genes was correlated to phenotypic beta-lactamic resistance. We conclude that CNS species from bovine milk presented significantly distinct antimicrobial resistance profiles, evaluated by phenotypic and genotypic tests, which has implications for treatment and management decisions.

Carga limite para juntas mecânicas em laminados de fibra de carbono

OpenAIRE

Arthur Chaves de Mas Santacreu

1989-01-01

Neste trabalho são testadas várias juntas parafusadas com laminados de fibra de carbono. São investigadas as influências dos parâmetros geométricos e dos parâmetros de constituição do laminado no comportamento da curva carga versus deformação do furo carregado. Paralelamente é desenvolvido um modelo de elementos finitos linear elástico para calcular a deformação do furo carregado a partir das propriedades mecânicas do material e da geometria da junta. É proposto um critério de previsão de car...

A population-based study examining the emergence of community-associated methicillin-resistant Staphylococcus aureus USA300 in New York City

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Panwar Monica

2006-11-01

Full Text Available Abstract Background Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA is a serious pathogen in several regions in the United States. It is unclear which populations are at high risk for the emergence of these strains. Methods All unique patient isolates of S. aureus were collected from hospitals in Brooklyn, NY over a three-month period. Isolates of MRSA that were susceptible to clindamycin underwent SCCmec typing. Isolates with the SCCmec type IV (characteristic of CA-MRSA strains underwent ribotyping. Demographic information involving the neighborhoods of Brooklyn was also gathered and correlated with the prevalence of CA-MRSA strains. Results Of 1316 isolates collected during the surveillance, 217 were MRSA susceptible to clindamycin. A total of 125 isolates possessed SCCmec type IV; 72 belonged to the USA300 strain and five belonged to the USA400 strain. Hospitals in the eastern part of the city had the highest prevalence of USA300 strain. Individuals in the eastern region, when compared to the western region, were more likely to be Black, Hispanic, female, and Conclusion The USA300 strain of CA-MRSA is emerging in New York City. In this population-based study, urban regions of lower socioeconomic status and with evidence of overcrowding appear to be at higher risk for the emergence of this pathogen.

Mobilização do paciente crítico em ventilação mecânica: relato de caso

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Sheila Suzana Glaeser

2012-07-01

Full Text Available A polineuropatia do paciente crítico (PNPC é uma patologia relativamente comum no ambiente de terapia intensiva e ocasiona aumento do tempo de internação e de ventilação mecânica. Uma das causas relacionadas a essa patologia é a imobilização do paciente. O caso relatado é de um paciente de 18 anos, desnutrido, usuário de crack e com vírus da imunodeficiência humana e tuberculose pulmonar e intestinal. O paciente apresentou insuficiência respiratória necessitando de ventilação mecânica (VM prolongada e PNPC associada. A fisioterapia com mobilização do paciente mesmo em uso de VM parece ter sido fundamental para a melhora da recuperação funcional associada à adequada nutrição e o tratamento das patologias apresentadas pelo paciente.

Nursing actions for the prevention of ventilator-associated pneumonia Acciones de enfermería en la profilaxis de la pneumonía asociada a la ventilación mecánica Ações de enfermagem na profilaxia da pneumonia associada à ventilação mecânica

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Fernanda Alves Ferreira Gonçalves

2012-01-01

Full Text Available OBJECTIVE: To identify prevention actions of the nursing team related to ventilator-associated pneumonia (VAP. METHOD: A cross-sectional, observational study conducted in an Intensive Care Unit of a teaching hospital in Goiania/GO. RESULTS: Hand hygiene occurred, mainly, after the procedures and most of care, such as elevating the head-of-bed, bronchial and oral hygiene, diet administration, also handlingmechanical ventilator circuits were not adequate and if experienced groups such as the one in the present study are not following the recommendations emerging from evidence, it may indicate that, for some reason, the learning is not being significant. CONCLUSION: Most recommendedmeasures to reduce VAP related to positioning the head-of-bed, bronchial and oral hygiene, administration of diet and handling mechanical ventilator circuit were not followed.OBJETIVOS: identificar las acciones del equipo de enfermería relacionadas a la profilaxis de la pneumonía asociada a la ventilación mecánica (PAV. MÉTODO: estudio transversal, observacional realizado en la Unidad de Cuidados Intensivos de un hospital docente de Goiânia/GO. RESULTADOS: La higiene de las manos ocurrió, sobre todo, después de los procedimientos y la mayoría de los cuidados como la elevación de la cabecera, higiene bronquial y bucal, administración de la dieta y también de los cuidados con los circuitos del ventilador mecánico no fueron adecuados y, si los grupos con experiencia como el del presente estudio, no están siguiendo las recomendaciones oriundas de las evidencias, puede ser indicio de que, por alguna razón, el aprendizaje no está siendo significativo. CONCLUSIÓN: La mayoría de las medidas recomendadas para reducir la PAV relacionadas a la posición de la cabecera de la cama, a la higiene bronquial y bucal, a la administración de la dieta y al manejo de los circuitos del ventilador mecânico, no fueron tomados en cuenta.OBJETIVOS: identificar as ações da

Estado del arte sobre el comportamiento físico-mecánico de la escayola reforzada con fibras de vidrio E

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Comino Almenara, Pablo

2004-10-01

Full Text Available This article contains a discussion of the results and conclusions obtained in different studies to determine the physical and mechanical performance of fibre-reinforced plaster/scagliola specimens. The reinforcement used in this case is short filaments of fibreglass-E, the type of fibre most widely used at this time in Spain to reinforce prefabricated plaster/scagliola.En este artículo se presentan los resultados y las conclusiones obtenidas en diferentes estudios, sobre el comportamiento físico y mecánico, realizados en probetas de yeso/escayola reforzadas mediante la incorporación de fibras, y, en concreto, de fibras de vidrio E, en formato de hilos cortados. Este tipo de fibras son las más utilizadas en la actualidad para el refuerzo en prefabricados de yeso/ escayola, en España.

Comportamento mecânico de sistemas de reforço de paredes de alvenaria

OpenAIRE

Menezes, Pedro Sucena Paiva de Calheiros e

2017-01-01

Na presente dissertação analisa-se o comportamento mecânico de reforços de paredes de alvenaria de pedra. As paredes de alvenaria de edifícios antigos necessitam frequentemente de ser reforçadas, para melhorar a capacidade resistente desses edifícios, em particular às ações sísmicas. Elabora-se uma pesquisa bibliográfica, trabalhos de campo e estudam-se trabalhos de referência experimentais. Apresenta-se neste trabalho um estudo experimental, em que se analisa o comportamento de um modelo ...

Cuidado de enfermería a la persona con soporte mecánico ventilatorio

OpenAIRE

González Consuegra, Renata Virginia

2012-01-01

A partir del concepto de Cuidado, se pretende mostrar las intervenciones del profesional de enfermería que son relevantes durante el cuidado de enfermería que requiere una persona con soporte mecánico ventilatorio, considerando siempre su prioridad como ser humano y no como una prolongación de una sofisticada maquina.Así, pues, partiendo de la valoración holistica del estado de salud, se muestran las posibilidades más frecuentes a resolver por un abordaje de Enfermería critico y analítico, si...

Análise proteômica de plasma de pacientes com infecção pulmonar associada à ventilação mecânica

OpenAIRE

Costa, Lucianna Auxi Teixeira Josino da

2016-01-01

Pneumonia associada à ventilação mecânica (PAV) tem altas prevalência e mortalidade. Fatores de risco somados aos os dados clínicos ajudam a sugeri-la, porém não a confirmam. O estudo microbiológico aumenta a acurácia diagnóstica e contribui no tratamento, porém nem sempre há crescimento bacteriano ou fúngico. Um perfil proteico plasmático auxiliaria no diagnóstico dos pacientes com infecção associada à ventilação mecânica. Cinquenta pacientes foram seguidos resultando em 14 com o diagnóstico...

Correlação entre permeabilidade e resistência mecânica de filtros cerâmicos no sistema Al2O3-SiC

OpenAIRE

Salvini,V. R.; Innocentini,M. D. M.; Pandolfelli,V. C.

2000-01-01

Tem sido crescente o uso de cerâmicas reticulares em processos de refino e purificação de metais fundidos, filtração de gases quentes e combustão catalítica. A aplicação depende da composição química e das propriedades físicas do material (número de poros por polegada linear (ppi), porosidade e diâmetro de poro). Há um consenso de que a melhoria das propriedades dos filamentos resulta em um melhor desempenho mecânico do filtro cerâmico. Entretanto, a análise dos valores de resistência mecânic...

Efficiency of three-phase asynchronous motors. Energy loss reduction by means of overdimensioning; Efficientie van driefasen asynchrone motoren. SinuMEC beperkt energieverlies door overdimensionering

Energy Technology Data Exchange (ETDEWEB)

Peeters, J.; Van Dorst, C. [Hyteps, Gemert (Netherlands)

2008-10-15

The three phase asynchronous motor has been applied in various installations since time immemorial. Although the motor is more efficient at full mechanical load, this is not always applied efficiently. Can the efficiency of low load motors be improved or is this a utopia? The Sinusoidal Motor Controller (SinuMEC) improves efficiency, saves energy and lengthens the life span. [mk]. [Dutch] De driefasen asynchrone motor wordt sinds mensenheugenis in uiteenlopende installaties toegepast. Hoewel de motor met een volle mechanische belasting efficient is, wordt deze niet altijd efficient toegepast. Kan de efficiency van laag belaste motoren worden verbeterd of is dit een utopie? De Sinusoidal Motor efficiency controller (SinuMEC) verbetert de efficiency, bespaart energie en verlengt de levensduur.

Para una reescritura de la filosofía: conciencia y mecánica cuántica

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Víctor Tapia

2000-07-01

Full Text Available A partir de este pretencioso título pretendo mostrar algunos desarrollos recientes de la mecánica cuántica con respecto al problema de la conciencia, la mente, el conocimiento, la voluntad, etc., desde el limitado punto de vista de un intruso curioso. El enfoque que ha empezado a tomar forma hace necesario reconsiderar todas nuestras ideas anteriores con respecto a la concepción del mundo.

Resistência mecânica do solo à penetração na bacia hidrográfica do Riacho Fundo, Felixlândia-MG

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Ana Paula Vilela Carvalho

2012-12-01

Full Text Available A compactação do solo devido ao tráfego de máquinas utilizadas no setor florestal causa modificações estruturais deste, podendo assim interferir na densidade do solo, velocidade e capacidade de infiltração de água e no desenvolvimento radicular das culturas. Objetivou-se, neste trabalho avaliar a resistência mecânica do solo à penetração na Bacia Hidrográfica do Riacho Fundo, Felixlândia-MG em área de uma empresa do setor florestal localizada no cerrado mineiro. Os testes de resistência à penetração foram realizados em fevereiro de 2011, em seis parcelas com plantios de eucalipto localizadas nos talhões 35, 36, 39, 40, 42 e 44, utilizando-se um penetrômetro de impacto. Os talhões apresentaram valores médios da resistência mecânica do solo acima de 4 MPa e esses altos valores podem estar associados ao uso do solo que antes dos plantios de eucalipto era pastagem e também devido a condição de baixo teor de umidade do solo no período em que foi realizada a determinação da resistência mecânica do solo.

DQ High genotypic diversity among methicillin-resistant Staphylococcus pseudintermedius isolated from canine infections in Denmark

DEFF Research Database (Denmark)

Damborg, Peter; Moodley, Arshnee; Aalbaek, Bent

2016-01-01

genotypic diversity and antimicrobial resistance of clinical MRSP isolates obtained from dogs, including dogs sampled on multiple occasions, in Denmark over a six-year period. For that purpose a total of 46 clinical MRSP isolates obtained from 36 dogs between 2009 and 2014 were subjected to antimicrobial...... susceptibility testing, multilocus-sequence typing (MLST) and SCCmec typing. Results: Twenty-three sequence types were identified with ST71, mostly associated with SCCmec II-III, as the most common occurring in 13 dogs. Among the remaining 33 isolates, 19 belonged to clonal complex (CC) 258 comprising ST258...... resistant and almost all CC258 isolates being susceptible. Sixteen of the 19 CC258 isolates had oxacillin MICs of 0.5 g/L, whereas MICs for CC71 isolates were consistently above 4 g/L. Four of five dogs representing multiple isolates had distinct STs on different sampling events. Conclusions: The overall...

"Análise da carga mecânica no joeho durante o agachamento"

OpenAIRE

Rogério Pessoto Hirata

2006-01-01

Existe um conceito difundido entre professores de educação física, fisioterapeutas e ortopedistas que o joelho não deve ser demasiadamente anteriorizado em relação à ponta do pé na direção ântero-posterior durante qualquer tipo de agachamento de modo a diminuir a carga mecânica imposta ao joelho. No entanto, são escassas as evidências quantitativas que corroboram este conceito. Este trabalho tem como objetivo estimar forças e torque na articulação do joelho em indivíduos saudáveis durante o e...

Associação entre a morfologia de trincas de pisos cerâmicos e seu comportamento mecânico em fratura

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E. S. Fonseca

2015-09-01

Full Text Available ResumoEste trabalho analisou os dados obtidos a partir de ensaios a flexão em um lote de 40 corpos de provas de placas cerâmicos, preparados da mesma forma de acordo com a norma brasileira de ensaios NBR 13818:1997. Os dados de resistência à flexão obtidos nos testes, na forma de curvas tensão versus flexão, foram avaliados estatisticamente. Análises estatísticas detalhadas mostraram dois subgrupos diferentes de comportamento mecânico apresentado pelos corpos de prova cerâmicos testados. A análise fractográfica de amostras representativas destes dois grupos indicaram diferenças morfológicas relevantes nas fraturas obtidas destas amostras durante o ensaio. Essas diferenças puderam ser associadas com o comportamento mecânico apresentados pelas amostras analisadas.

Plantas que causam alterações mecânicas ou traumáticas em ruminantes e equinos, com ênfase em Stipa spp. (Gramineae

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Beatriz Riet-Correa

2011-06-01

Full Text Available Várias plantas podem provocar algum tipo de injúria mecânica. Entre elas as que causam traumatismo da pele ou mucosas, e as que causam alterações do sistema digestório, incluindo obstrução esofágica, sobrecarga ruminal e obstrução intestinal. Neste trabalho são revisadas algumas plantas que causam essas alterações e é descrito um surto de injúria mecânica causada por Stipa spp. (flechilha em ovinos no Uruguai. Os animais, principalmente os cordeiros, apresentavam grande quantidade dos frutos de flechilha incrustadas na lã e alguns desses se introduziam na pele, panículo adiposo e músculo cutâneo do tronco causando dermatite e paniculite multifocal difusa.

Ventilação mecânica na doença pulmonar obstrutiva crônica Mechanical ventilation in chronic obstructive pulmonary disease

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Sérgio Jezler

2007-06-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: Em 2000, foi publicado o II Consenso Brasileiro de Ventilação Mecânica. Desde então, o conhecimento na área da ventilação mecânica avançou rapidamente, com a publicação de numerosos estudos clínicos que acrescentaram informações importantes para o manejo de pacientes críticos em ventilação artificial. Além disso, a expansão do conceito de Medicina Baseada em Evidências determinou a hierarquização das recomendações clínicas, segundo o rigor metodológico dos estudos que as embasaram. Essa abordagem explícita vem ampliando a compreensão e a aplicação das recomendações clínicas. Por esses motivos, a AMIB - Associação de Medicina Intensiva Brasileira - e a SBPT - Sociedade Brasileira de Pneumologia e Tisiologia - julgaram conveniente a atualização das recomendações descritas no Consenso anterior. Dentre os tópicos selecionados a Ventilação Mecânica na Agudização da DPOC foi um dos temas propostos. O objetivo deste estudo foi descrever os pontos mais importantes relacionados à ventilação mecânica durante a agudização da doença pulmonar obstrutiva crônica (DPOC e sugerir as principais abordagens terapêuticas. MÉTODO: Objetivou-se chegar a um documento suficientemente sintético, que refletisse a melhor evidência disponível na literatura. A revisão bibliográfica baseou-se na busca de estudos através de palavras-chave e em sua gradação conforme níveis de evidência. As palavras-chave utilizadas para a busca foram: ventilação mecânica na DPOC: COPD and mechanical ventilation. RESULTADOS: São apresentadas recomendações quanto aos modos ventilatórios e aos parâmetros a serem aplicados quando do ajuste do ventilador, além da monitoração recomendada. Apresentam-se ainda, técnicas alternativas que possam ser utilizadas. CONCLUSÕES: Estratégias protetoras de ventilação mecânica são recomendadas durante a ventilação mecânica de um paciente DPOC

Ventilação mecânica não-invasiva com pressão positiva Noninvasive mechanical ventilation with positive pressure

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Guilherme P. P. Schettino

2007-06-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: Em 2000, foi publicado o II Consenso Brasileiro de Ventilação Mecânica. Desde então, o conhecimento na área da ventilação mecânica avançou rapidamente, com a publicação de numerosos estudos clínicos que acrescentaram informações importantes para o manejo de pacientes críticos em ventilação artificial. Além disso, a expansão do conceito de Medicina Baseada em Evidências determinou a hierarquização das recomendações clínicas, segundo o rigor metodológico dos estudos que as embasaram. Essa abordagem explícita vem ampliando a compreensão e a aplicação das recomendações clínicas. Por esses motivos, a AMIB - Associação de Medicina Intensiva Brasileira - e a SBPT - Sociedade Brasileira de Pneumologia e Tisiologia - julgaram conveniente a atualização das recomendações descritas no Consenso anterior. Dentre os tópicos selecionados a Ventilação Mecânica Não-Invasiva foi um dos temas propostos. O objetivo deste estudo foi descrever os pontos mais importantes relacionados à ventilação mecânica na forma não-invasiva (VMNI e sugerir as principais indicações dessa modalidade. MÉTODO: Objetivou-se chegar a um documento suficientemente sintético, que refletisse a melhor evidência disponível na literatura. A revisão bibliográfica baseou-se na busca de estudos através de palavras-chave e em sua gradação conforme níveis de evidência. As palavras-chave utilizadas para a busca foram: Ventilação mecânica não invasiva: Non-invasive mechanical ventilation. RESULTADOS: São apresentadas recomendações quanto à utilização da VMNI nas diversas formas de insuficiência respiratória e no desmame da ventilação mecânica. CONCLUSÕES: A VMNI está indicada como o tratamento preferencial na exacerbação da DPOC, assim como, na assistência de pacientes em edema agudo de pulmão.BACKGROUND AND OBJECTIVES: The II Brazilian Consensus Conference on Mechanical Ventilation was

Efecto de la desestabilización de la cementita sobre el desarrollo de altos niveles de resistencia mecánica en aceros perlíticos

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Mykhaylo Romanyuk

2016-01-01

Full Text Available Se estudió la deformación en aceros de alto contenido de carbono trefilados en frío, sobre el comportamiento mecánico y de fractura. La deformación promueve fenómenos de disolución de la cementita en la perlita, alcanzando alta resistencia y ductilidad, lo que permite aplicarlos en usos críticos como cables de grúas. Para estudiar el comportamiento mecánico y a la fractura, se estudian muestras de dos alambres sometidas a torsión hasta rotura. Estos presentan distinto comportamiento: uno sufrió fractura plana (normal y otro fractura delaminada. Se efectúa un estudio estructural mediante microscopía óptica y electrónica de barrido. Los resultados obtenidos muestran la presencia del fenómeno de rizado (curling. Además, se realizan ensayos de análisis térmico diferencial y simulación termodinámica aplicando Fact Sage, para analizar la estabilidad de carburos. Se corroboró la precipitación de carburos épsilon que ocurre por difusión de carbono en la interfaz ferrita-perlita, justificando el incremento de la resistencia mecánica.

Propriedades físicas, químicas e mecânicas da madeira de cedro australiano cultivado em Corupá, SC

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Rosilani Trianoski

2014-12-01

Full Text Available O cedro australiano (Toona ciliata M. Roem é uma espécie de elevado valor comercial, com características similares ao mogno e cedros nativos, que vem se destacando em plantios florestais no Brasil, cuja madeira produzida deve ser alvo de pesquisas tecnológicas. O objetivo deste trabalho foi avaliar as propriedades físicas, químicas e mecânicas desta espécie em plantio com 18 anos. Foi observada massa específica baixa (0,330 g cm3, estabilidade dimensional média baixa (anisotropia: 2,22, teor de extrativos elevado (10,33% e propriedades mecânicas moderadas: MOR e MOE à flexão: 498 kgf cm-2 e 66.163 kgf cm-2; MOR e MOE à compressão paralela: 258 kgf cm-2 e 100,813 kgf cm-2; cisalhamento: 82 kgf cm-2, e dureza média: 208 kgf.

Evaluación a lo largo del tiempo de las propiedades mecánicas de los bloques de suelo-cemento utilizados en pavimentos semipermeables

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M. Carvalho

Full Text Available Un pavimento semipermeable fue construido con una capa de revestimiento de bloques de suelo-cemento hechos de suelo de desmonte (estabilizado con 30% de arena y cemento (con 20% de la mezcla y fabricados con una prensa. Este tipo de bloque no tiene estudios adicionales acerca de las mudanzas del comportamiento de las propiedades mecánicas a lo largo del tempo, entonces para realizar el estudio se seleccionaron algunos bloques (con 7, 14, 28, 130 y 1650 días de moldeado para medir las propiedades mecánicas (de durabilidad, de absorción de agua y de resistencia a compresión sencilla. Los resultados demostraron que no hubo mudanzas en las propiedades de absorción y de durabilidad de los bloques, después de 1650 días. La resistencia a la compresión tuvo un leve incremento de 9MPa (28 días de moldeados para 12MPa (1650 días de moldeados, bloques del pavimento en uso, lo que puede ser atribuido a las reacciones que todavía suceden entre cemento, suelo y agua o a la variabilidad de materia prima y de los equipamientos utilizados. Concluyese que las condiciones ambientales y el tráfico leve no afectaron las propiedades mecánicas de los bloques, entonces ellos pueden ser utilizados en pavimento semipermeable.

Nueva nave de Ensayos Mecánicos en el Instituto Eduardo Torroja

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Echegaray Comba, G.

1968-07-01

Full Text Available This important building meets an urgent need at the Institute Eduardo Torroja to have a mechanical testing hall that is capable of dealing with all kinds of tests that are likely to arise in the foreseeable future. In designing it account has been taken of all requirements anticipated as a result of the experience obtained during the use of the earlier testing hall which the Institute already has. The new testing hall consists essentially of a metallic structure, 33.50 m high, 11.50 m wide and 8 m high, enclosed by prefabricated LECA type panels. The hall has a powerful reinforced concrete slab, 11.50 m wide and 25.50 m long, which is 1.20 m thick. The slab has 270 anchorage points, with a load capacity of 50 t and 100 t each. These points can be loaded singly, or in groups. The slab rests on two lateral reinforced concrete walls, of 80 cm thickness. Below the slab there is a basement, which can be used in conjunction with the hall above for testing purposes, since the anchorage points make it possible to communicate both sides of the slab. A careful system of illumination has also been provided, and heavy vehicles can enter both the basement and the main hall. One ten ton bridge crane has been installed, although two such cranes can be fitted. All calculations have been done with the aid of the electronic computer of the I.E.T.c.c. The total design makes this project one of the most important of its type in Europe.A los quince años de estrenar la primera nave de Ensayos Mecánicos con que contó el Instituto, se inaugura esta segunda nave. A ella nos vamos a referir en el presente artículo, esencialmente descriptivo. No obstante, son tan singulares las razones que han motivado su necesidad que, aunque sea en forma sumamente breve, creemos de interés dar cuenta de ellas en este preámbulo.

Caracterización mecánica de recubrimientos de aluminio por CVD-FBR sobre aceros inoxidables y resistencia a la oxidación en vapor de agua

OpenAIRE

Diego Pérez-Muñoz; José Luddey Marulanda-Arévalo; Juan Manuel Meza-Meza

2015-01-01

Los recubrimientos de aluminio depositados sobre el acero inoxidable austenítico AISI 317 por Deposición Química de Vapor en Lecho Fluidizado (CVD-FBR) presentan a altas temperaturas una reducción de la velocidad de corrosión de más de 80 veces. Se realizó la caracterización mecánica de los recubrimientos por medio de microdureza, nanoindentación, para conocer cómo se vieron afectas las propiedades mecánicas (en especial la dureza y el módulo de Young) del recubrimiento y del sustrato luego d...

Implementación del secado mecánico de café en carros secadores

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Oscar Buitrago Bermúdez

1991-09-01

Full Text Available Con el objetivo de presentar una nueva alternativa de secado a los pequeños y medianos ceficultores, se desarrolló un secador mecánico de capa fija, a partir de un secador solar de tradicional uso en la zona cafetera denominado carro secador, el cual consta de dos a cuatro plataformas de secado, un entramado de soporte y desplazamiento de las plataformas y un techo de teja de zinc para resguardarlas en caso de lluvia. Se hicieron las modificaciones necesarias para convertir el carro secador en un secador mecánico, se tuvo en cuenta que el secador pudiera seguirse usando como secador solar, se realizaron seis pruebas de secado, en las cuales se midieron variables del grano, del aire y del secador. La uniformidad del contenido de humedad final del grano se determinó comparando muestras tomadas en las plataformas y después de empacado el grano. De la evaluación del equipo se hicieron las siguientes deducciones: - Cada una de las partes acondicionadas al carro funcionaron satisfactoriamente. No se presentaron fugas de aire caliente. - El consumo de combustible del quemador de olla fue 0.239 y 0.275 L. kg café pergamino seco (c.p.s.. - El caudal de aire aumentó al final del secado alrededor del 90%, debido a la disminución continua del espesor de la capa de grano. - Los consumos energéticos del secador estuvieron 4500 y 7000 kJ.kg c.p.s. - El contenido de humedad final del grano fue uniforme, con coeficientes de variación cercanos al 10%.

Microestructura y propiedades mecánicas del SiC biomórfico obtenido a partir de eucalipto

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Presas, M.

2005-12-01

Full Text Available The development of cellular ceramics with a biological structure, like bones and wood, has been a matter of interest in recent years. A low density highly interconnected structure, perfected by evolution, rises as the principal advantage of these materials. In the case of biomimetic SiC (biomorphic SiC, or bioSiC, the fabrication process technique is quite simple: a piece of wood is pyrolysed and is infiltrated with molten silicon after, the final product is a composite Si/SiC, which replicates the wood anisotropic microstructure This work focus on the mechanical properties of bioSiC fabricated using eucalyptus wood as precursor (hard wood with a bimodal channel distribution. It has been studied the mechanical behavior of this bioSiC (compression strength, flexure strength, fracture toughness and elastic modulus between 25 and 1350 oC. It is also discussed the relationship between mechanical behavior of the material and its microstructure.

El desarrollo de materiales cerámicos con una estructura de tipo celular, similar a la del hueso o la madera, ha sido una cuestión que ha suscitado un gran interés en los últimos años. Su atractivo se debe al hecho de poseer una estructura porosa altamente interconectada de baja densidad, perfeccionada por la evolución. En el caso del SiC biomórfico (bio-SiC el proceso de fabricación es sencillo: se piroliza una pieza de madera y a continuación se inyecta con silicio líquido, el material así obtenido es un compuesto Si/SiC en el que el SiC mimetiza la estructura de la madera original. En este trabajo se estudian las propiedades mecánicas del SiC biomórfico fabricado a partir de eucalipto (madera dura con una distribución bimodal de poros. Se ha estudiado el comportamiento mecánico del mismo (resistencia a compresión, resistencia a flexión, tenacidad de fractura y módulo de elasticidad entre 25 y 1350 oC. Asimismo, se discute la relación entre el comportamiento mecánico del material y

High proportions of Staphylococcus epidermidis in dental caries harbor multiple classes of antibiotics resistance, significantly increase inflammatory interleukins in dental pulps.

Science.gov (United States)

Devang Divakar, Darshan; Muzaheed; Aldeyab, Sultan Salem; Alfawaz, Sara A; AlKheraif, Abdulaziz Abdullah; Ahmed Khan, Aftab

2017-08-01

Staphylococcus epidermidis is one of most prevalent in dental caries or dental pulp which has the capability of horizontal genetic transfer between different bacterial species in the oropharynx, suggesting that it may evolve with the dissemination of resistant determinants, This study was performed to molecularly characterize and differentiate S. epidermidis isolated from dental caries and healthy individual. Also, two important cytokines in inflammation were assayed caused due to S. epidermidis of health and dental caries sources. Dental caries strains were more resistant with high MIC 50 and MIC 90 value. These isolates also showed the presence of mecA gene and another virulence gene i. e sea and seb comparatively more than healthy individual isolates. SCCmec types, III and IV was more prevalent in dental caries isolates where an as healthy individual was more non-typable. Additionally, the quantity of IL-1β and IL-8 caused due to dental caries isolates was seen more which indicate dental caries isolates are able to induce. This study showed that S. epidermidis a normal flora of oropharyngeal are more diverse to those strains which cause dental caries. S. epidermidis owns a prodigious genetic plasticity that permits to obtain, lose or regulate genetic elements that provide compensations to improve its colonization in the host. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physical and metabolic alterations in "Prata Anã" banana induced by mechanical damage at room temperature Alterações físicas e metabólicas em banana 'Prata Anã' induzidas por dano mecânico mantidas sob temperatura ambiente

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Victor Martins Maia

2011-02-01

Full Text Available Bananas respond at the physical and physiological level to mechanical damage. Mechanical injuries cause alterations in color and flavor, tissue softening, faster ripening, increased weight loss, increased invasion of microorganisms, and higher enzyme activity in the affected area. The purpose of this study was to verify the physical and metabolic alterations in 'Prata Anã' bananas induced by mechanical stress at room temperature. The experiment was conducted in a completely randomized, split-plot in time design, consisting of one control and four mechanical injury types: cutting, abrasion, impact and compression, sampled over time. The percentage of accumulated and daily fresh weight loss, electrolyte leakage from the injured peel region, total soluble sugar and starch contents and enzyme activity of polyphenoloxidase and peroxidase were measured. The damage caused by cutting and abrasion resulted in the highest percentage of fresh weight loss. All types of mechanical damage increased electrolyte leakage during the evaluation period, in comparison with the control. The impact damage anticipated the ripening, besides affecting the conversion of starch into total soluble sugars in the pulp. By impact and abrasion injuries, the polyphenoloxidase and peroxidase activity in the peel was increased by up to 231% and 90%, and 618% and 956%, respectively, compared to the control.Bananas apresentam respostas físicas e fisiológicas ao dano mecânico. As injúrias mecânicas causam alterações na cor e sabor, amaciamento dos tecidos, amadurecimento mais rápido, aumento na perda de peso, aumento no ataque e invasão de microorganismos e maior atividade enzimática na área afetada. Verificaramse alterações físicas e metabólicas induzidas por estresse mecânico em bananas 'Prata Anã' mantidas em temperatura ambiente. Foi utilizado o esquema em parcelas subdivididas no tempo, constituído de testemunha e quatro fontes de dano mecânico: corte, abras

Avaliação do gerenciamento de resíduos de óleos lubrificantes e suas embalagens em oficinas mecânicas da cidade de Pombal – PB, Brasil

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Michel Almeida da Silva

2014-09-01

Full Text Available As oficinas mecânicas de veículos automotivos são empreendimentos geradores de um volume considerável de resíduos de óleos lubrificantes e de suas embalagens, os quais podem causar alterações significativas no meio ambiente quando gerenciados de modo inadequado. O presente trabalho teve por objetivo realizar uma avaliação ambiental com respeito à geração, armazenamento, coleta, transporte, tratamento e disposição final dos resíduos de óleos lubrificantes e de suas embalagens gerados por meio das atividades desenvolvidas em oficinas mecânicas da cidade de Pombal - PB. Esse estudo foi motivado pelo notável aumento da frota de veículos automotivos na cidade, e, por consequência, pelo crescimento da procura por serviços de oficinas mecânicas. O método de avaliação fundamentou-se num levantamento de informações documentais e de campo por meio da aplicação de questionários, bem como nas análises das instalações físicas das 10 oficinas visitadas, que foram escolhidas de forma aleatória e estão distribuídas em diferentes bairros da cidade. Com base nos resultados obtidos, foi possível notar que há uma urgente necessidade de um adequado gerenciamento dos resíduos de óleos lubrificantes e de suas embalagens nas oficinas mecânicas da cidade de Pombal - PB.

La asistencia mecánica circulatoria en las Guías de Insuficiencia Cardíaca 2012: novedades y comentarios

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Enrique Pérez de la Sota

2013-01-01

El objeto del presente trabajo es analizar el capítulo dedicado al soporte mecánico circulatorio en estas nuevas guías y comentar de forma crítica las novedades aportadas, así como su posible aplicabilidad en España dadas las especiales características de la asistencia en nuestro país.

Propriedades mecânicas, tribológicas e térmicas de nanocompósitos de PLLA com nanotubos de carbono de paredes múltiplas

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Jonas Bertholdi

2014-08-01

Full Text Available Neste trabalho são estudados os efeitos da adição de nanotubos de carbono de parede múltipla (NCPM em uma matriz de Poli(L-ácido láctico (PLLA. Foras avaliadas duas rotas distintas de dispersão dos NCPM, uma utilizando agitação mecânica em solvente e a outra utilizando sonificação de alta energia em solvente. As propriedades mecânicas destes nanocompósitos foram avaliadas utilizando nanoindentação e microdureza vickers. Através da calorimetria exploratória diferencial foram determinadas as propriedades térmicas dos nanocompósitos (Tg, Tc, Tm e cristalinidade obtidas. Por último, as propriedades tribológicas foram determinadas através de ensaios de deslizamento do tipo pino sobre disco, onde foram utilizadas diferentes cargas normais. As propriedades mecânicas e térmicas não foram significativamente afetadas pela adição do nanotubos, o que não se repetiu nas propriedades tribológicas, onde tanto o método de dispersão quanto a concentração de NCPM afetaram as propriedades. A micrografia das trilhas de desgaste sugere ainda que o mecanismo atuante foi modificado com a incorporação dos nanotubos, o mesmo pode ter acontecido nas amostras sonificadas.

Staphylococcus sciuri bacteriophages double-convert for staphylokinase and phospholipase, mediate interspecies plasmid transduction, and package mecA gene.

Science.gov (United States)

Zeman, M; Mašlaňová, I; Indráková, A; Šiborová, M; Mikulášek, K; Bendíčková, K; Plevka, P; Vrbovská, V; Zdráhal, Z; Doškař, J; Pantůček, R

2017-04-13

Staphylococcus sciuri is a bacterial pathogen associated with infections in animals and humans, and represents a reservoir for the mecA gene encoding methicillin-resistance in staphylococci. No S. sciuri siphophages were known. Here the identification and characterization of two temperate S. sciuri phages from the Siphoviridae family designated ϕ575 and ϕ879 are presented. The phages have icosahedral heads and flexible noncontractile tails that end with a tail spike. The genomes of the phages are 42,160 and 41,448 bp long and encode 58 and 55 ORFs, respectively, arranged in functional modules. Their head-tail morphogenesis modules are similar to those of Staphylococcus aureus ϕ13-like serogroup F phages, suggesting their common evolutionary origin. The genome of phage ϕ575 harbours genes for staphylokinase and phospholipase that might enhance the virulence of the bacterial hosts. In addition both of the phages package a homologue of the mecA gene, which is a requirement for its lateral transfer. Phage ϕ879 transduces tetracycline and aminoglycoside pSTS7-like resistance plasmids from its host to other S. sciuri strains and to S. aureus. Furthermore, both of the phages efficiently adsorb to numerous staphylococcal species, indicating that they may contribute to interspecies horizontal gene transfer.

Efeito do corte como dano mecânico na qualidade e na fisiologia de mamões 'golden'

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Jaqueline Visioni Tezotto

2011-10-01

Full Text Available A redução na qualidade pós-colheita do mamão deve-se em grande parte aos danos mecânicos, especialmente àqueles do tipo corte. O objetivo deste trabalho foi reproduzir este dano mecânico e avaliar os efeitos do número de cortes na qualidade e na fisiologia pós-colheita de mamões 'Golden'. Os cortes foram obtidos com o uso de uma lâmina de aço de 30 mm de comprimento e 5 mm de profundidade. Os tratamentos consistiram na reprodução de 1 a 4 cortes na região mediana dos frutos. Mamões sem cortes foram utilizados como controle. Após a reprodução dos danos, os frutos foram armazenados em câmara a 22ºC e 80-90% de UR por 10 dias. As análises de qualidade foram realizadas a cada dois dias, e as fisiológicas, diariamente. Os resultados demonstraram que a firmeza, o teor de sólidos solúveis e de ácido ascórbico, a atividade respiratória e a produção de etileno foram influenciados pelo número de cortes, de forma que a perda de qualidade dos frutos foi diretamente proporcional ao número de cortes.

Bovine-associated MRSA ST398 in The Netherlands

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Tavakol Mehri

2012-05-01

Full Text Available Abstract During routinely screening (50.000 milk samples on an annual basis 14 MRSA ST398 strains were identified in the period of January 2008 to September 2008 in 14 different dairy herds located in the provinces Overijssel and Gelderland, The Netherlands. Molecular analysis was performed by Cfr9I PFGE, ST398-specific diagnostic PCR, spa typing, SCCmec typing and Panton-Valentine Leukocidin (PVL gene PCR. The molecular analyses of 14 MRSA (one MRSA strain per herd strains revealed that all strains belong to ST398 with 3 closely related spa types (t011, t108 and t889, all commonly found in pigs and carry 2 different SCCmec types, IVa and V. All MRSA strains were resistant to two or more classes of antibiotics and also PVL negative. The majority of farms (n = 9, 64% harboured combined livestock with both cows and pigs present. Our study contributes to the growing evidence that MRSA ST398 is transmitted among various animal species and can be considered as an etiological agent of mastitis in dairy cows.

Caracterização fenogenotípica da resistência antimicrobiana em Staphylococcus spp. isolados de mastite bovina

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Elaine C.L. Mendonça

2012-09-01

Full Text Available A utilização de antibióticos no controle das infecções intramamárias e na eliminação de prováveis fontes de infecção nas fazendas leiteiras se constitui em importante medida de controle. No entanto, o uso inadequado de antibióticos no tratamento da doença pode selecionar cepas resistentes e comprometer a eficiência do tratamento. Bactérias do gênero Staphylococcus spp. estão entre os principais agentes etiológicos da mastite bovina e são freqüentemente resistentes aos antimicrobianos, em especial aos beta-lactâmicos, principalmente por dois mecanismos distintos: a produção da enzima extracelular beta-lactamase, codificada pelo gene blaZ, e a produção de PBP2a ou PBP2´, uma proteína ligante de penicilina de baixa afinidade, codificada pelo gene mecA. A expressão do gene mecA é constitutiva ou induzida por antibióticos betalactâmicos, como a oxacilina e cefoxitina. O gene mecA está inserido no cromossomo através de um elemento genético móvel, denominado cassete estafilocócico cromossômico mec (SCCmec. O presente estudo avaliou o perfil fenogenotípico de resistência aos beta-lactâmicos em 250 isolados de Staphylococcus spp., utilizando os marcadores oxacilina e cefoxitina, de modo a produzir dados que possam contribuir para o conhecimento da resistência antimicrobiana em algumas propriedades leiteiras das regiões Sul-Fluminense e Metropolitana do Estado do Rio de Janeiro com o objetivo de subsidiar a implementação de medidas de controle dessa enfermidade. A avaliação da resistência foi feita a partir de 8 diferentes testes fenotípicos, sendo obtidos 54 perfis. Os testes de difusão em disco simples e ágar screen com oxacilina foram utilizados como "padrão ouro" para os cálculos dos valores de sensibilidade, especificidade e predição por serem preconizados pelo CLSI veterinário. O teste de difusão em disco simples com cefoxitina foi o de melhor desempenho na predição da resistência a

Propiedades térmicas, acústicas y mecánicas de placas de mortero caucho-cemento.

OpenAIRE

Bustamante Montoro, Rosa; Mayor Lobo, Pablo; Hernandez Olivares, Francisco; Rangel, C.

2008-01-01

Se presentan los principales resultados de una investigación sobre la fabricación de losas de mortero de cemento común y metacaolín, que incorporan crecientes fracciones volumétricas de polvo de caucho triturado procedente de neumáticos fuera de uso (NFU), hasta superar el 30% en volumen del producto final. Se describen las dosificaciones y las principales propiedades físicas y mecánicas de los productos obtenidos, comparándolas entre sí y con las de losas similares sin polvo de caucho. Se in...

Desenvolvimento de um sistema mecânico para limpeza e classificação de ostras

OpenAIRE

Novaes, André Luís Tortato

2005-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Mecânica. A ostreicultura é uma atividade econômica relativamente recente em Santa Catarina, tendo sido implantada comercialmente a cerca de quinze anos. Desde a instalação dos primeiros cultivos comerciais até a atualidade a produção de ostras tem aumentado a cada ano, transformando o estado de Santa Catarina no maior produtor nacional deste molusco. Com a evolução ...

Caracterización mecánica de materiales de base colágeno para aplicaciones cardiovasculares

OpenAIRE

Tobaruela Arnedo, María de la Almudena

2016-01-01

Las enfermedades cardiovasculares son una de las principales causas de muerte en el mundo. Este hecho ha propiciado que numerosas investigaciones se hayan centrado en la mejora de las prótesis cardiovasculares ya existentes así como en la búsqueda de nuevos materiales más resistentes, duraderos y biocompatibles. Actualmente, existen dos tipos principales de prótesis valvulares: las mecánicas y las biológicas. En muchos países cada vez es más frecuente el uso de estas últimas. Las válvulas bio...

Transmission of MDR MRSA between primates, their environment and personnel at a United States primate centre.

Science.gov (United States)

Soge, Olusegun O; No, David; Michael, Karen E; Dankoff, Jennifer; Lane, Jennifer; Vogel, Keith; Smedley, Jeremy; Roberts, Marilyn C

2016-10-01

MDR MRSA isolates cultured from primates, their facility and primate personnel from the Washington National Primate Research Center were characterized to determine whether they were epidemiologically related to each other and if they represented common local human-associated MRSA strains. Human and primate nasal and composite environmental samples were collected, enriched and selected on medium supplemented with oxacillin and polymyxin B. Isolates were biochemically verified as Staphylococcus aureus and screened for the mecA gene. Selected isolates were characterized using SCCmec typing, MLST and WGS. Nasal cultures were performed on 596 primates and 105 (17.6%) were MRSA positive. Two of 79 (2.5%) personnel and two of 56 (3.6%) composite primate environmental facility samples were MRSA positive. Three MRSA isolates from primates, one MRSA from personnel, two environmental MRSA and one primate MSSA were ST188 and were the same strain type by conventional typing methods. ST188 isolates were related to a 2007 ST188 human isolate from Hong Kong. Both MRSA isolates from out-of-state primates had a novel MLST type, ST3268, and an unrelated group. All isolates carried ≥1 other antibiotic resistance gene(s), including tet(38), the only tet gene identified. ST188 is very rare in North America and has almost exclusively been identified in people from Pan-Asia, while ST3268 is a newly reported MRSA type. The data suggest that the primate MDR MRSA was unlikely to come from primate centre employees. Captive primates are likely to be an unappreciated source of MRSA. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Joint conference of iMEC 2015 (2nd International Manufacturing Engineering Conference & APCOMS 2015 (3rd Asia-Pacific Conference on Manufacturing Systems)

Science.gov (United States)

2016-02-01

The iMEC 2015 is the second International Manufacturing Engineering Conference organized by the Faculty of Manufacturing, Universiti Malaysia Pahang (UMP), held from 12-14th November 2015 in Kuala Lumpur, Malaysia, with a theme "Materials, Manufacturing and Systems for Tomorrow". For the first time, iMEC is organized together with 3rd Asia- Pacific Conference on Manufacturing System (APCOMS 2015) which owned by Fakulti Teknologi Industri, Institut Teknologi Bandung (ITB), Indonesia. This is an extended collaboration between UMP and ITB to intensify knowledge sharing and experiences between higher learning institutions. This conference (iMEC & APCOMS 2015) is a platform for knowledge exchange and the growth of ideas, particularly in manufacturing engineering. The conference aims to bring researchers, academics, scientists, students, engineers and practitioners from around the world together to present their latest findings, ideas, developments and applications related to manufacturing engineering and other related research areas. With rapid advancements in manufacturing engineering, iMEC is an appropriate medium for the associated community to keep pace with the changes. In 2015, the conference theme is “Materials, Manufacturing and Systems for Tomorrow” which reflects the acceleration of knowledge and technology in global manufacturing. The papers in these proceedings are examples of the work presented at the conference. They represent the tip of the iceberg, as the conference attracted over 200 abstracts from Malaysia, Indonesia, Japan, United Kingdom, Australia, India, Bangladesh, South Africa, Turkey and Morocco and 151 full papers were accepted in these proceedings. The conference was run in four parallel sessions with 160 presenters sharing their latest finding in the areas of manufacturing process, systems, advanced materials and automation. The first keynote presentation was given by Prof. B. S. Murthy (IIT, Madras) on "Nanomaterials with Exceptional

Genetic relatedness, antimicrobial and biocide susceptibility comparative analysis of methicillin-resistant and -susceptible Staphylococcus pseudintermedius from Portugal.

Science.gov (United States)

Couto, Natacha; Belas, Adriana; Couto, Isabel; Perreten, Vincent; Pomba, Constança

2014-08-01

Forty methicillin-resistant and -susceptible Staphylococcus pseudintermedius (MRSP and MSSP, respectively) from colonization and infection in dogs and cats were characterized for clonality, antimicrobial, and biocide susceptibility. MSSP were genetically more diverse than MRSP by multi-locus sequence typing and pulsed-field gel electrophoresis. Three different spa types (t06, t02, t05) and two SCCmec types (II-III and V) were detected in the MRSP isolates. All MRSP and two MSSP strains were multidrug-resistant. Several antibiotic resistance genes (mecA, blaZ, tet(M), tet(K), aac(6')-Ie-aph(2')-Ia, aph(3')-III, ant(6)-Ia, sat4, erm(B), lnu(A), dfr(G), and catp(C221)) were identified by microarray and double mutations in the gyrA and grlA genes and a single mutation in the rpoB gene were detected by sequence analysis. No differences were detected between MSSP and MRSP in the chlorhexidine acetate (CHA) minimum inhibitory concentrations (MICs). However, two MSSP had elevated MIC to triclosan (TCL) and one to benzalkonium chloride and ethidium bromide. One MSSP isolate harboured a qacA gene, while in another a qacB gene was detected. None of the isolates harboured the sh-fabI gene. Three of the biocide products studied had high bactericidal activity (Otodine(®), Clorexyderm Spot Gel(®), Dermocanis Piocure-M(®)), while Skingel(®) failed to achieve a five log reduction in the bacterial counting. S. pseudintermedius have become a serious therapeutic challenge in particular if methicillin- resistance and/or multidrug-resistance are involved. Biocides, like CHA and TCL, seem to be clinically effective and safe topical therapeutic options.

Diseño de conexiones mecánicas tipo canal en vigas compuestas bajo fuego//Design of channel mechanical connections in composite beam in

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Yisel Larrua‐Pardo

2015-01-01

Full Text Available En este trabajo se propusieron dos métodos, uno simplificado y otro gráfico alternativo para el diseño de la conexión mecánica tipo canal en vigas compuestas de hormigón y acero en situación de incendio, a partir del estudio de su comportamiento. Se utilizó como herramienta la modelación numérica. El método simplificado desarrollado considera temperaturas definidas a través de la modelación térmica del ensayo push-out en situación de incendio y es coherente con las expresiones de diseño de las conexiones mecánicas tipo canal a temperatura ambiente y la formulación existente para el diseño de las conexiones tipo perno a elevadas temperaturas. El método gráfico alternativopropuesto constituye una opción que permite obtener de una forma directa y rápida, la resistencia a elevadas temperaturas de la conexión mecánica tipo canal para un tiempo de resistencia al fuego, en función de su resistencia a temperatura ambiente.Palabras claves: conexión mecánica tipo canal, método simplificado, método gráfico alternativo, modelación numérica, incendio._______________________________________________________________________________AbstractIn this paper two methods to design of channel mechanical connection are proposed, a simplified one and graphical alternative another, both using the numerical analysis for the study of the mechanical connection behavior. The developed simplified method considers temperatures defined through thethermal modelling of the push-out test in fire and it is coherent with the design expressions of the channel mechanical connections to ambient temperature, and the current formulation for the design of the stud connections al elevated temperatures. The proposed alternative graphical method constitutes an option that allows obtaining, in a direct and quick way, the resistance to elevatedtemperatures of the channel mechanical connections for a determined time of resistance to the fire, according to its

238. Prótesis percutáneas: el fin de la prótesis mecánica

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C. Porras

2012-04-01

Dado el bajo riesgo que representa una primera reintervención, especialmente a edad relativamente joven, creemos recomendable expandir la edad en la que se implantan prótesis biológicas en posición aórtica y difícil de justificar la implantación de prótesis mecánicas en dicha posición, salvo en pacientes muy jóvenes en los que la reparación valvular o el procedimiento de Ross no sean posibles.

Tipos e intensidade de danos mecânicos em bananas 'prata-anã' ao longo da cadeia de comercialização Types and intensity of mechanical damages on 'prata anã' bananas along the commercialization chain

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Victor Martins Maia

2008-06-01

Full Text Available Atualmente, a maior parte da produção brasileira de banana é destinada ao mercado interno e, geralmente, é colhida, manuseada e transportada de forma deficiente e inadequada, contribuindo para perdas substanciais na fase pós-colheita. Objetivou-se identificar os tipos e a intensidade de danos mecânicos após a colheita da banana 'Prata-Anã', produzida no Município de Verdelândia (MG e embalada em caixas de papelão, madeira e plástico. Foram amostradas quatro caixas de banana 'Prata-Anã' em cada etapa da cadeia de comercialização, a saber: antes da colheita, após a primeira lavagem e pré-seleção (1ª piscina da casa de embalagem, após embalagem, após transporte e após distribuição ao mercado varejista em Montes Claros (MG, onde os frutos permaneceram em exposição para vendas por 8 horas. A porcentagem de frutos, área da casca e porcentagem da área da casca danificados aumentou ao longo da cadeia de comercialização. O uso da caixa de papelão proporcionou redução na incidência e intensidade de dano mecânico em relação aos demais tipos de embalagem. Houve alta incidência do dano por abrasão em todas as etapas da cadeia de comercialização. O dano por compressão apresentou grande importância relativa no varejo.Currently, most of the Brazilian production of banana is destined for domestic market and, generally, it is harvested, handled and carried in a deficient and inadequate form, contributing to substantial post harvest losses. This work had the objective of identifying the types and the intensity of mechanical damages after the harvest of 'Prata Anã' banana grown in Verdelândia, MG and put in cardboard, wood and plastic boxes. So, four boxes of banana were evaluated in each stage of the commercialization chain: before harvest, after the first washing and pre-selection (1st swimming pool of the packing house, after packing, after transport and distribution to the retail market in Montes Claros, MG, where

Propiedades mecánicas de un Rhodic Ferralsol requeridas para la simulación de la interacción suelo implemento de labranza mediante el Método de Elementos Finitos: Parte I

OpenAIRE

Miguel Herrera Suárez; Ciro E. Iglesias Coronel; Omar González Cueto; Elvis López Bravo; Ángel Sánchez Iznaga

2008-01-01

El Método de Elementos Finitos se ha convertido en una poderosa herramienta para diferentes procesos de simulación. En el presente trabajo se investigan las propiedades mecánicas de un Rhodic Ferralsol requeridas para la simulación de la interacción suelo-apero de labranza mediante el método antes mencionado. Para cumplimentar dicho objetivo se recolectó el suelo en las áreas experimentales del Instituto Nacional de Ciencias Agrícolas (INCA), y se determinaron en el laboratorio de mecánica de...

Comparação entre um método de diagnóstico clínico e a técnica de vigilância do Center for Disease Control and Prevention para identificação de pneumonia associada à ventilação mecânica

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Renata Waltrick

2015-09-01

Full Text Available RESUMOObjetivo:Avaliar a concordância entre um novo método de vigilância epidemiológica do Center for Disease Control and Prevention e o Clinical Pulmonary Infection Score para detecção de pneumonia associada à ventilação mecânica.Métodos:Coorte prospectiva que avaliou pacientes internados nas unidades de terapia intensiva de dois hospitais que permaneceram intubados por mais de 48 horas no período de agosto de 2013 a junho de 2014. Os pacientes foram avaliados diariamente pelos fisioterapeutas com o Clinical Pulmonary Infection Score. De forma independente, um enfermeiro aplicou o novo método de vigilância proposto pelo Center for Disease Control and Prevention. Avaliou-se a concordância diagnóstica entre os métodos. Clinical Pulmonary Infection Score ≥ 7 foi considerado diagnóstico clínico de pneumonia associada à ventilação mecânica, considerando-se diagnóstico definitivo a associação de Clinical Pulmonary Infection Score ≥ 7 com germe isolado em cultura semiquantitativa ≥ 104 unidades formadoras de colônias.Resultados:De 801 pacientes admitidos nas unidades de terapia intensiva, 198 estiveram sob ventilação mecânica. Destes, 168 permaneceram intubados por mais de 48 horas. Identificaram-se 18 (10,7% condições infecciosas associadas à ventilação mecânica e 14 (8,3% pneumonias associadas à ventilação mecânica possíveis ou prováveis, representando 35% (14/38 diagnósticos clínicos de pneumonia associada à ventilação mecânica. O método do Center for Disease Control and Prevention identificou casos de pneumonia associada à ventilação mecânica com sensibilidade de 0,37 e especificidade de 1,0, com valor preditivo positivo de 1,0 e negativo de 0,84. As diferenças implicaram em discrepâncias na densidade de incidência de pneumonia associada à ventilação mecânica (CDC: 5,2/1000 dias de ventilação mecânica; Clinical Pulmonary Infection Score ≥ 7: 13,1/1000 dias de ventilação mec

Análisis combinado acústico-mecánico durante el almacenamiento de cebolla (allium fistulosum mínimamente procesada

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Andrea González

2012-01-01

Full Text Available La cebolla de rama (Allium fistulosum es una hortaliza altamente perecedera debido a su contenido de humedad, a su elevada tasa metabólica y al deficiente manejo poscosecha al cosecharla y transportarla. El objetivo de esta investigación fue determinar la relación entre el deterioro visual del producto y los cambios generados en las propiedades mecánicas y acústicas del mismo. Se utilizó cebolla de rama cultivada en Aquitania, Boyacá Colombia, sometida a condiciones: empaque a vacío (10 mbar y sin empaque (HR 68%; y almacenada a 4 oC y 16 oC, hasta deterioro por apariencia visual. Los cambios mecánico acústicos en firmeza, crujencia y fractura para la cebolla sin empaque y almacenado a 4 °C se presentaron en el día 15 de almacenamiento, y el deterioro visual en el día 13. Para el producto sin empaque almacenado a 16 °C, el mayor cambio se presentó el día sexto. El producto empacado a vacío y almacenado a 4 °C presentó cambios mecánico acústicos y de apariencia visual en el día 15 y para el producto empacado a vacío y almacenado a 16 °C se presentaron cambios en el día seis, en las características de firmeza, crujencia y fracturabilidad, coincidiendo con la disminución de la apariencia visual. En términos generales fue más evidente el cambio en la disminución de la fracturabilidad para la cebolla almacenada a 16 oC, en las dos condiciones de empaque. Los métodos instrumentales empleados permitieron aproximar el tiempo de deterioro de cebolla mínimamente procesada, en beneficio del establecimiento de la vida útil percibida por aspecto visual.

Cage-rotor induction motor inter-turn short circuit fault detection with and without saturation effect by MEC model.

Science.gov (United States)

Naderi, Peyman

2016-09-01

The inter-turn short fault for the Cage-Rotor-Induction-Machine (CRIM) is studied in this paper and its local saturation is taken into account. However, in order to observe the exact behavior of machine, the Magnetic-Equivalent-Circuit (MEC) and nonlinear B-H curve are proposed to provide an insight into the machine model and saturation effect respectively. The electrical machines are generally operated near to their saturation zone due to some design necessities. Hence, when the machine is exposed to a fault such as short circuit or eccentricities, it is operated within its saturation zone and thus, time and space harmonics are integrated and as a result, current and torque harmonics are generated which the phenomenon cannot be explored when saturation is dismissed. Nonetheless, inter-turn short circuit may lead to local saturation and this occurrence is studied in this paper using MEC model. In order to achieve the mentioned objectives, two and also four-pole machines are modeled as two samples and the machines performances are analyzed in healthy and faulty cases with and without saturation effect. A novel strategy is proposed to precisely detect inter-turn short circuit fault according to the stator׳s lines current signatures and the accuracy of the proposed method is verified by experimental results. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

O Plano de Desenvolvimento da Educação: análise do projeto do MEC The Education Development Plan (EDP: analysis of the project of the Ministry of Education (MEC

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Dermeval Saviani

2007-10-01

Full Text Available Este artigo se propõe a analisar globalmente a proposta do MEC, visando responder à seguinte pergunta: Em que medida esse novo plano se revela efetivamente capaz de enfrentar a questão da qualidade do ensino das escolas de educação básica? Para tanto, serão considerados os seguintes pontos: 1. A configuração do PDE, procurando entender sua composição e identificar cada uma das 30 ações em que ele se desdobra; 2. Análise da singularidade do plano em confronto com os planos anteriores, em especial com o vigente Plano Nacional de Educação; 3. A singularidade do PDE diante do problema da qualidade da educação básica; 4. As bases de sustentação do plano, visando verificar o grau em que está apto a assegurar a qualidade da educação básica; 5. Finalmente, à guisa de conclusão, sugere-se um caminho para superar as limitações do PDE.This article seeks to analyze globally the proposal of the Ministry of Education (MEC by answering the following question: to what extent is this new Plan effectively able to face the quality problem of basic education?* It thus explores the following elements: 1. The edp framework, in order to understand its composition and identify each one of the 30 actions in which it is divided; 2. An analysis of the singularity of this plan compared to the previous one, especially the current National Education Plan; 3. The singularity of the edp when faced with the problem of the quality of basic education; 4. The foundations of the plan, by verifying to what extent it is apt to ensure the quality of basic education; 5. Finally, as a conclusion, a way to overcome the limitations of the edp is suggested.

Evaluación del comportamiento mecánico y superficial de materiales metálicos sometidos a tratamientos de compresión mediante ondas de choque generadas por láser

OpenAIRE

Gutiérrez González, Javier

2016-01-01

El presente trabajo de fin de grado se ha desarrollado en el Centro Láser de la Universidad Politécnica de Madrid y ha consistido en la caracterización mecánica y superficial del acero AISI 316L tras haber sido tratado mediante el tratamiento “Laser peening” y el estudio de la estabilidad de las tensiones residuales inducidas al ser sometido a un tratamiento a 500ºC durante dos horas. El tratamiento LSP es un tratamiento mecánico superficial que consiste en la creación de ondas de choque ...

Different doses of exogenous surfactant for treatment of meconium aspiration syndrome in newborn rabbits Estudo dos efeitos de diferentes doses de surfactante exógeno para o tratamento da síndrome de aspiração de mecônio em coelhos recém-nascidos

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João Cesar Lyra

2004-01-01

Full Text Available OBJECTIVE: To evaluate the effects of 2 different doses of exogenous surfactant on pulmonary mechanics and on the regularity of pulmonary parenchyma inflation in newborn rabbits. METHOD: Newborn rabbits were submitted to tracheostomy and randomized into 4 study groups: the Control group did not receive any material inside the trachea; the MEC group was instilled with meconium, without surfactant treatment; the S100 and S200 groups were instilled with meconium and were treated with 100 and 200 mg/kg of exogenous surfactant (produced by Instituto Butantan respectively. Animals from the 4 groups were mechanically ventilated during a 25-minute period. Dynamic compliance, ventilatory pressure, tidal volume, and maximum lung volume (P-V curve were evaluated. Histological analysis was conducted using the mean linear intercept (Lm, and the lung tissue distortion index (SDI was derived from the standard deviation of the means of the Lm. One-way analysis of variance was used with a = 0.05. RESULTS: After 25 minutes of ventilation, dynamic compliance (mL/cm H2O · kg was 0.87 ± 0.07 (Control; 0.49 ± 0.04 (MEC*; 0.67 ± 0.06 (S100; and 0.67 ± 0.08 (S200, and ventilatory pressure (cm H2O was 9.0 ± 0.9 (Control; 16.5 ± 1.7 (MEC*; 12.4 ± 1.1 (S100; and 12.1 ± 1.5 (S200. Both treated groups had lower Lm values and more homogeneity in the lung parenchyma compared to the MEC group: SDI = 7.5 ± 1.9 (Control; 11.3 ± 2.5 (MEC*, 5.8 ± 1.9 (S100; and 6.7 ± 1.7 (S200 (*P OBJETIVO: Avaliar os efeitos de duas diferentes doses de surfactante exógeno sobre a mecânica pulmonar e sobre a regularidade da expansão do parênquima pulmonar em coelhos recém-nascidos. MÉTODO: Coelhos recém-nascidos foram traqueostomizados e randomizados em quatro grupos de estudo: grupo-Controle, sem aspiração de mecônio; grupo MEC, com aspiração de mecônio e sem tratamento com surfactante exógeno; grupos S100 e S200, ambos com aspiração de mecônio e tratados

La mecánica cuántica de David Bohm: formalismo matemático e implicaciones epistemológicas

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Rodrigo Siqueira-Batista

2014-11-01

Full Text Available La interpretación bohmiana de la Mecánica Cuántica representa una de las principales alternativas al modelo hegemónico propuesto por la Escuela de Copenhague, permitiendo una descripción determinista de los eventos ocurridos a nivel cuántico. El objetivo del presente artículo es presentar sucintamente sus principales aspectos matemáticos y conceptuales —y sus respectivas implicaciones epistemológicas.

Efeito da fertilização em propriedades mecânicas da madeira de Eucalyptus grandis

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Israel Luiz de Lima

2011-01-01

estática. A resistência à compressão e o módulo de elasticidade foram influenciados pelos fatores: adubo e posição da tora. Todas as propriedades mecânicas aumentaram no sentido da medula para a casca. Foi observada uma relação positiva entre resistência à compressão paralela às fibras, cisalhamento, módulo de resistência à flexão estática e módulo de elasticidade na flexão estática com a posição radial.

Propiedades térmicas, acústicas y mecánicas de placas de morteros de yeso-caucho.

OpenAIRE

Mayor Lobo, Pablo; Bustamante Montoro, Rosa; Rangel, C.; Hernandez Olivares, Francisco

2008-01-01

Se presentan los principales resultados de una investigación sobre la fabricación de losas de escayola, que incorporan crecientes fracciones volumétricas de polvo de caucho triturado procedente de neumáticos fuera de uso (NFU), hasta superar el 50% en volumen del producto final. Se describen las dosificaciones y las principales propiedades físicas y mecánicas de los productos obtenidos, comparándolas entre sí y con las de losas similares sin polvo de caucho. Se incluyen también medidas experi...

Análisis de señales de medidas mecánicas para el mantenimiento predictivo avanzado

OpenAIRE

Montalvo Martín, Cristina

2012-01-01

Para contribuir al diseño de un mantenimiento mecánico avanzado, se utilizan en esta tesis las técnicas de análisis de ruido para monitorizar las vibraciones de los internos de un reactor PWR y para vigilar la respuesta dinámica de los sensores de presión capacitivos tipo Rosemount ampliamente utilizados en la industria, sobre todo en las plantas nucleares. Para el primer caso, se han ajustado mediante un método no lineal de Breit- Wigner los espectros de resonancias obtenidos por medio de la...

Análisis de señales de medidas mecánicas para el mantenimiento predictivo avanzado

OpenAIRE

Montalvo Martín, Cristina

2010-01-01

Para contribuir al diseño de un mantenimiento mecánico avanzado, se utilizan en esta tesis las técnicas de análisis de ruido para monitorizar las vibraciones de los internos de un reactor PWR y para vigilar la respuesta dinámica de los sensores de presión capacitivos tipo Rosemount ampliamente utilizados en la industria, sobre todo en las plantas nucleares. Para el primer caso, se han ajustado mediante un método no lineal de Breit- Wigner los espectros de resonancias obtenidos por medio de la...

A importância da pressão pleural na avaliação da mecânica respiratória La importancia de la presión pleural en la evaluación de la mecánica respiratoria Importance of pleural pressure for the evaluation of respiratory mechanics

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Cláudia Regina Fernandes

2006-06-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: Para a partição das medidas de mecânica do sistema respiratório em seus componentes pulmão e parede torácica, faz-se necessário o conhecimento da pressão pleural. A finalidade desta revisão foi discutir sobre medidas alternativas à obtenção da pressão pleural para o cálculo da mecânica pulmonar, relatar as peculiaridades do método do balão esofágico para obtenção indireta da pressão pleural, as particularidades da obtenção da medida da pressão esofágica em pacientes sedados ou anestesiados, discorrer sobre a medida direta da pressão pleural e sua correlação com a pressão esofágica, assim como relatar sobre o reflexo da PEEP nas pressões pleural e esofágica. CONTEÚDO: A variação da pressão intra-esofágica reflete a variação da pressão intrapleural, podendo ser usada como medida alternativa à pressão pleural direta, no estudo da mecânica dos componentes pulmão e parede do sistema respiratório. A medida da pressão esofágica pode ser realizada por meio de um delicado balão posicionado no interior do esôfago. O método e a técnica foram observados e validados em seres humanos e animais em diferentes condições e posturas corporais. O emprego da PEEP em pacientes sob ventilação controlada mecânica está consolidado; no entanto, existem controvérsias da correlação próxima entre a pressão esofágica e a pressão pleural em pacientes ventilados com PEEP, o que pode resultar em erros de cálculo de mecânica respiratória considerando a pressão esofágica. CONCLUSÕES: O método do balão esofágico é o mais utilizado para a obtenção da medida indireta da pressão pleural. Em pacientes sedados ou anestesiados sem alterações significativas da complacência respiratória, a variação da pressão esofágica corresponde à variação da pressão pleural quando a PEEP é aplicada.JUSTIFICATIVA Y OBJETIVOS: Para la partición de las medidas de mecánica del sistema

Clinical and Molecular Epidemiology of Infective Endocarditis in Intravenous Drug Users

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Pei-Jiuan Chao

2009-12-01

Conclusion: Our results suggest that coinfection with hepatitis C was common in intravenous drug users with IE, and that molecular patterns of MRSA isolates had high similarity. SCCmec type III, which is usually hospital-acquired, could have caused the community-associated MRSA endocarditis in our patients.

Heterogeneity among methicillin-resistant Staphylococcus aureus from Italian pig finishing holdings

DEFF Research Database (Denmark)

Battisti, A.; Franco, A.; Merialdi, G.

2010-01-01

A survey for methicillin-resistant Staphylococcus aureus (MRSA) in finishing pig holdings was carried out in Italy in 2008. MRSA isolates were characterised by spa-. SCCmec- and antimicrobial susceptibility typing. A prevalence of 38% (45/118, 95% CI 29.4-46.9%) positive holdings was observed...

Genetic diversity of methicillin-resistant Staphylococcus aureus in a tertiary hospital in The Netherlands between 2002 and 2006

NARCIS (Netherlands)

Nulens, E; Stobberingh, E E; Smeets, E; van Dessel, H; Welling, M A; Sebastian, S; van Tiel, F H; Beisser, P S; Deurenberg, R H

The aim of this study was to investigate the methicillin-resistant Staphylococcus aureus (MRSA) clones isolated in a Dutch university hospital, situated near the borders of Belgium and Germany, between 2002 and 2006. MRSA strains (n = 175) were characterized using spa and SCCmec typing. The presence

Estudio del fenómeno de electroplasticidad atérmica en el comportamiento mecánico y metalúrgico del acero AISI-SAE 4140 ensayado a tracción

OpenAIRE

Montilla Montaña, Carlos A.; González Rojas, Hernan Alberto; Higuera Cobos, Oscar Fabián; Kallewaard, Valentina; Sánchez Egea, Antonio José

2018-01-01

El fenómeno de electroplasticidad (EP por sus siglas en inglés) consiste en el cambio de las propiedades mecánicas de un metal, debido a la aplicación simultánea de esfuerzos mecánicos de tracción, compresión, flexión, etc., y pulsos instantáneos de corriente. Los cambios en la tasa de deformación plástica propiciados por la EP se deben a efectos térmicos como efecto Joule, y a efectos atérmicos de campos magnéticos y eléctricos. Hay pocos estudios que den cuenta del efecto electro plástico e...

Joint conference of iMEC 2015 (2nd International Manufacturing Engineering Conference and APCOMS 2015 (3rd Asia-Pacific Conference on Manufacturing Systems)

International Nuclear Information System (INIS)

2016-01-01

The iMEC 2015 is the second International Manufacturing Engineering Conference organized by the Faculty of Manufacturing, Universiti Malaysia Pahang (UMP), held from 12-14th November 2015 in Kuala Lumpur, Malaysia, with a theme 'Materials, Manufacturing and Systems for Tomorrow'. For the first time, iMEC is organized together with 3rd Asia- Pacific Conference on Manufacturing System (APCOMS 2015) which owned by Fakulti Teknologi Industri, Institut Teknologi Bandung (ITB), Indonesia. This is an extended collaboration between UMP and ITB to intensify knowledge sharing and experiences between higher learning institutions. This conference (iMEC and APCOMS 2015) is a platform for knowledge exchange and the growth of ideas, particularly in manufacturing engineering. The conference aims to bring researchers, academics, scientists, students, engineers and practitioners from around the world together to present their latest findings, ideas, developments and applications related to manufacturing engineering and other related research areas. With rapid advancements in manufacturing engineering, iMEC is an appropriate medium for the associated community to keep pace with the changes. In 2015, the conference theme is “Materials, Manufacturing and Systems for Tomorrow” which reflects the acceleration of knowledge and technology in global manufacturing. The papers in these proceedings are examples of the work presented at the conference. They represent the tip of the iceberg, as the conference attracted over 200 abstracts from Malaysia, Indonesia, Japan, United Kingdom, Australia, India, Bangladesh, South Africa, Turkey and Morocco and 151 full papers were accepted in these proceedings. The conference was run in four parallel sessions with 160 presenters sharing their latest finding in the areas of manufacturing process, systems, advanced materials and automation. The first keynote presentation was given by Prof. B. S. Murthy (IIT, Madras) on &apos

Microbiological and molecular characterization of human clinical isolates of Staphylococcus cohnii, Staphylococcus hominis, and Staphylococcus sciuri.

Science.gov (United States)

Garza-González, Elvira; Morfin-Otero, Rayo; Martínez-Vázquez, Manuel A; Gonzalez-Diaz, Esteban; González-Santiago, Omar; Rodríguez-Noriega, Eduardo

2011-12-01

The incidence of coagulase-negative staphylococci reported as causative agents of nosocomial infections has risen in the last decade. The aim of this study was to characterize biofilm formation, antibiotic resistance, SCCmec type, and genetic relatedness in clinical isolates of Staphylococcus cohnii, Staphylococcus hominis, and Staphylococcus sciuri recovered from humans. Clinically relevant isolates of S. cohnii (n = 15), S. hominis (n = 9), and S. sciuri (n = 6), were collected from patients. Biofilm formation was evaluated using crystal violet staining, drug susceptibility was assessed using the broth microdilution method, and methicillin resistance was measured using the cefoxitin disk test. SCCmec was typed using 2 different methodologies, and genetic relatedness was determined by pulsed-field gel electrophoresis (PFGE). Sixty percent (9/15) of S. cohnii, 33% (3/9) of S. hominis, and 50% (3/6) of S. sciuri isolates were categorized as weak producers of biofilm. None of the isolates were resistant to vancomycin or linezolid. All 3 species showed a high resistance (> 66%) to ampicillin, levofloxacin, erythromycin, and ceftriaxone, and the majority of the isolates were methicillin-resistant. PFGE revealed that the S. cohnii isolates comprised 1 dominant clone. The S. cohnii, S. hominis, and S. sciuri isolates analyzed in this study showed a high methicillin resistance and resistance to other antimicrobials. The results of this study strongly suggest that coagulase-negative staphylococci harbour new SCCmec elements. We report the first case of a clone of S. cohnii associated with human disease.

An epidemiologic survey of methicillin-resistant Staphylococcus aureus by combined use of mec-HVR genotyping and toxin genotyping in a university hospital in Japan.

Science.gov (United States)

Nishi, Junichiro; Yoshinaga, Masao; Miyanohara, Hiroaki; Kawahara, Motoshi; Kawabata, Masaharu; Motoya, Toshiro; Owaki, Tetsuhiro; Oiso, Shigeru; Kawakami, Masayuki; Kamewari, Shigeko; Koyama, Yumiko; Wakimoto, Naoko; Tokuda, Koichi; Manago, Kunihiro; Maruyama, Ikuro

2002-09-01

To evaluate the usefulness of an assay using two polymerase chain reaction-based genotyping methods in the practical surveillance of methicillin-resistant Staphylococcus aureus (MRSA). Nosocomial infection and colonization were surveyed monthly in a university hospital in Japan for 20 months. Genotyping with mec-HVR is based on the size of the mec-associated hypervariable region amplified by polymerase chain reaction. Toxin genotyping uses a multiplex polymerase chain reaction method to amplify eight staphylococcal toxin genes. Eight hundred nine MRSA isolates were classified into 49 genotypes. We observed differing prevalences of genotypes for different hospital wards, and could rapidly demonstrate the similarity of genotype for outbreak isolates. The incidence of genotype D: SEC/TSST1 was significantly higher in isolates causing nosocomial infections (49.5%; 48 of 97) than in nasal isolates (31.4%; 54 of 172) (P = .004), suggesting that this genotype may represent the nosocomial strains. The combined use of these two genotyping methods resulted in improved discriminatory ability and should be further investigated.

Qualidade de maçãs 'Fuji Suprema' submetidas a diferentes tipos de dano mecânico Quality of apples 'Fuji Suprema' subject to different mechanical damages

Directory of Open Access Journals (Sweden)

Marcos Vinicius Hendges

2011-06-01

Full Text Available Objetivo deste trabalho foi avaliar o efeito do dano mecânico por impacto, compressão e corte sobre a qualidade de maçãs 'Fuji Suprema' mantidas em condição ambiente. Os tratamentos avaliados foram: controle (sem dano mecânico, dano mecânico por impacto, dano mecânico por compressão e dano mecânico por corte. Os diferentes danos não influenciaram na firmeza de polpa e no ângulo 'hue' da casca. O dano por corte proporcionou frutos com menor acidez titulável, nove dias após a aplicação do dano. Frutos submetidos ao dano por impacto apresentaram maior teor de sólidos solúveis, quinze dias após a aplicação dos danos. Os danos por impacto e corte causaram o menor valor de L da polpa em todas as avaliações, evidenciando o escurecimento da polpa. Contudo, este efeito não foi observado na epiderme. Todos os frutos danificados por corteapresentaram podridão após nove dias da aplicação dos danos.De maneira geral, pode-se concluir que, nas intensidades testadas, maçãs 'Fuji Suprema' submetidas ao dano por impacto e corte apresentam prejuízos em sua qualidade, pois ocorre escurecimento da polpa no local do dano. Além disso, o dano por corte reduz a vida pós-colheita dos frutos, facilitando a ocorrência de podridões.The objective of this work was to evaluate the effect of mechanical damage by impact, compression and cut on the quality of 'Fuji Suprema' apples in ambient conditions. The treatments were: control (no mechanical damage and mechanical damage by impact, compression and cut. Different mechanical damages did not influence the flesh firmness and hue angle of the skin. Cut damage provided fruits with lower titratable acidity, nine days after damages application. Fruits submitted to damage by impact showed higher soluble solids content, 15 days after damages application. For the L color index of the flesh, cut and impact damages caused the smallest value in all evaluations, characterizing the flesh browning. However

Can widely used cell type markers predict the suitability of immortalized or primary mammary epithelial cell models?

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Edgar Corneille Ontsouka

Full Text Available BACKGROUND: Mammary cell cultures are convenient tools for in vitro studies of mammary gland biology. However, the heterogeneity of mammary cell types, e.g., glandular milk secretory epithelial or myoepithelial cells, often complicates the interpretation of cell-based data. The present study was undertaken to determine the relevance of bovine primary mammary epithelial cells isolated from American Holstein (bMEC US or Swiss Holstein-Friesian (bMEC CH cows, and of primary bovine mammary alveolar epithelial cells stably transfected with simian virus-40 (SV-40 large T-antigen (MAC-T for in vitro analyses. This was evaluated by testing their expression pattern of cytokeratin (CK 7, 18, 19, vimentin, and α-smooth muscle actin (α-SMA. RESULTS: The expression of the listed markers was assessed using real-time quantitative PCR, flow cytometry and immunofluorescence microscopy. Characteristic markers of the mesenchymal (vimentin, myoepithelial (α-SMA and glandular secretory cells (CKs showed differential expression among the studied cell cultures, partly depending on the analytical method used. The relative mRNA expression of vimentin, CK7 and CK19, respectively, was lower (P < 0.05 in immortalized than in primary mammary cell cultures. The stain index (based on flow cytometry of CK7 and CK19 protein was lower (P < 0.05 in MAC-T than in bMECs, while the expression of α-SMA and CK18 showed an inverse pattern. Immunofluorescence microscopy analysis mostly confirmed the mRNA data, while partly disagreed with flow cytometry data (e.g., vimentin level in MAC-T. The differential expression of CK7 and CK19 allowed discriminating between immortal and primary mammary cultures. CONCLUSIONS: The expression of the selected widely used cell type markers in primary and immortalized MEC cells did not allow a clear preference between these two cell models for in vitro analyses studying aspects of milk composition. All tested cell models exhibited to a variable

Estudos das propriedades mecânicas e térmicas do polímero biodegradável poli-3-hidroxibutirato (PHB) e de compósitos PHB/pó de madeira.

OpenAIRE

Miriam Lúcia Chiquetto Machado

2008-01-01

O objetivo deste trabalho foi o estudo das propriedades mecânicas e térmicas do PHB e de compósitos de PHB/pó de madeira processados, reprocessados e irradiados. Foram preparados compósitos com PHB e pó de madeira com concentrações de PHB/pó de madeira de 90/10, 80/20 e 70/30 (m/m). Foram realizados ensaios de propriedades mecânicas, HDT, ponto de amolecimento Vicat, TGA e DSC. A incorporação do pó de madeira aumentou o grau de cristalinidade e a temperatura de cristalização do polímero, e no...

Mecânica pulmonar de pacientes em suporte ventilatório na unidade de terapia intensiva. Conceitos e monitorização Concepts and monitoring of pulmonary mechanic in patients under ventilatory support in intensive care unit

Directory of Open Access Journals (Sweden)

Eduardo Antonio Faustino

2007-06-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: Em ventilação mecânica invasiva e não-invasiva, o conhecimento da fisiologia da mecânica respiratória, é imprescindível para tomada de decisões e no manuseio eficiente dos ventiladores modernos. A monitorização dos parâmetros da mecânica pulmonar é recomendada nos trabalhos de revisão e de pesquisas clínicas. O objetivo deste estudo foi rever os conceitos de mecânica pulmonar e os métodos utilizados para obtenção de medidas à beira do leito, enfatizando três parâmetros: resistência, complacência e PEEP intrínseca. MÉTODO: Foi realizada revisão bibliográfica através dos bancos de dados LILACS, MedLine e PubMed, no período de 1996 a 2006. RESULTADOS: Esta revisão abordou os parâmetros de resistência, complacência pulmonar e PEEP intrínseca como fundamentais na compreensão da insuficiência respiratória aguda e suporte ventilatório mecânico, principalmente na doença pulmonar obstrutiva crônica (DPOC e na síndrome da angústia respiratória aguda (SARA. CONCLUSÕES: A monitorização da mecânica pulmonar em pacientes sob ventilação mecânica em unidade de terapia intensiva (UTI pode fornecer dados relevantes e deve ser implementada de forma sistemática e racional.BACKGROUND AND OBJECTIVES: In mechanical ventilation, invasive and noninvasive, the knowledge of respiratory mechanic physiology is indispensable to take decisions and into the efficient management of modern ventilators. Monitoring of pulmonary mechanic parameters is been recommended from all the review works and clinical research. The objective of this study was review concepts of pulmonary mechanic and the methods used to obtain measures in the bed side, preparing a rational sequence to obtain this data. METHODS: It was obtained bibliographic review through data bank LILACS, MedLine and PubMed, from the last ten years. RESULTS: This review approaches parameters of resistance, pulmonary compliance and intrinsic PEEP

Biofilm Formation and Its Relationship with the Molecular Characteristics of Food-Related Methicillin-Resistant Staphylococcus aureus (MRSA).

Science.gov (United States)

Vergara, Alberto; Normanno, Giovanni; Di Ciccio, Pierluigi; Pedonese, Francesca; Nuvoloni, Roberta; Parisi, Antonio; Santagada, Gianfranco; Colagiorgi, Angelo; Zanardi, Emanuela; Ghidini, Sergio; Ianieri, Adriana

2017-10-01

The capability to produce biofilm is an important persistence and dissemination mechanism of some foodborne bacteria. This paper investigates the relationship between some molecular characteristics (SCCmec, ST, spa-type, agr-type, cna, sarA, icaA, icaD, clfA, fnbA, fnbB, hla, hlb) of 22 food-related methicillin-resistant Staphylococcus aureus (MRSA) strains and their ability to form biofilm on stainless steel and polystyrene. Five (22.7%, 5/22) strains were able to synthesize biofilm on polystyrene, and one of these (4.5%, 1/22) strains was also able to synthesize biofilm on stainless steel. The largest amount of biofilm was formed on polystyrene by 2 MRSA strains isolated from cows' milk, thus raising concern about the dairy industry. The majority of MRSA biofilm producers carried SCCmec type IVa, suggesting that the presence of SCCmecIVa and/or agr type III could be related to the ability to form biofilm. In conclusion, in order to achieve an acceptable level of food safety, Good Hygiene Practices should be strictly implemented along the food chain to reduce the risk of colonization and dissemination of MRSA biofilm-producing strains in the food industry. In this study, some assayed isolates of food-related MRSA demonstrated the capacity to form biofilm. Biofilm formation differed according to surface characteristics and MRSA strains. A relationship was observed between some molecular characteristics and the ability to form biofilms. Few studies have investigated the ability of MRSA to form biofilms, and the majority of these studies have investigated clinical aspects. This work was performed to investigate whether or not there is a difference between MRSA food isolates and MRSA clinical isolates in their ability to form biofilm. These initial findings could provide information that will contribute to a better understanding of these aspects. © 2017 Institute of Food Technologists®.

Chromosomal Targeting by the Type III-A CRISPR-Cas System Can Reshape Genomes in Staphylococcus aureus.

Science.gov (United States)

Guan, Jing; Wang, Wanying; Sun, Baolin

2017-01-01

CRISPR-Cas (clustered regularly interspaced short palindromic repeat [CRISPR]-CRISPR-associated protein [Cas]) systems can provide protection against invading genetic elements by using CRISPR RNAs (crRNAs) as a guide to locate and degrade the target DNA. CRISPR-Cas systems have been classified into two classes and five types according to the content of cas genes. Previous studies have indicated that CRISPR-Cas systems can avoid viral infection and block plasmid transfer. Here we show that chromosomal targeting by the Staphylococcus aureus type III-A CRISPR-Cas system can drive large-scale genome deletion and alteration within integrated staphylococcal cassette chromosome mec (SCC mec ). The targeting activity of the CRISPR-Cas system is associated with the complementarity between crRNAs and protospacers, and 10- to 13-nucleotide truncations of spacers partially block CRISPR attack and more than 13-nucleotide truncation can fully abolish targeting, suggesting that a minimal length is required to license cleavage. Avoiding base pairings in the upstream region of protospacers is also necessary for CRISPR targeting. Successive trinucleotide complementarity between the 5' tag of crRNAs and protospacers can disrupt targeting. Our findings reveal that type III-A CRISPR-Cas systems can modulate bacterial genome stability and may serve as a high-efficiency tool for deleting resistance or virulence genes in bacteria. IMPORTANCE Staphylococcus aureus is a pathogen that can cause a wide range of infections in humans. Studies have suggested that CRISPR-Cas systems can drive the loss of integrated mobile genetic elements (MGEs) by chromosomal targeting. Here we demonstrate that CRISPR-mediated cleavage contributes to the partial deletion of integrated SCC mec in methicillin-resistant S. aureus (MRSA), which provides a strategy for the treatment of MRSA infections. The spacer within artificial CRISPR arrays should contain more than 25 nucleotides for immunity, and consecutive

Propiedades mecánicas y tribológicas de materiales nanoestructurados de carburo de silicio/nanofibras de carbono

Directory of Open Access Journals (Sweden)

Borrell, A.

2011-06-01

Full Text Available The development of new ceramic/carbon nanostructured materials is a very interesting option from the point of view of the automotive and aerospace industries. Its low density, high mechanical strength, high oxidation resistance and excellent friction behavior allows the use of these composites as functional materials. The aim of this study was to evaluate the influence of carbon nanofibers (CNFs on the mechanical and tribological behavior of silicon carbide/CNFs nanocomposite obtained by spark plasma sintering technique. The tribological study was carried out in a ball-on-disk apparatus under dry sliding conditions (dry friction and a fixed load of 15 N. The friction coefficient and wear rate were measured for each composite. Scanning electron microscope was used to analyze wear surface formed. The results show simultaneous improvement of wear behavior and mechanical properties of ceramic materials by incorporating of carbon nanofibers.

Los materiales compuestos cerámica/carbono poseen excelentes propiedades que los convierten en candidatos idóneos para diversas aplicaciones. Entre otras cabe destacar su empleo en frenos de aviones o coches de competición. Su baja densidad, alta resistencia mecánica, elevada resistencia a la oxidación, excelente comportamiento a fricción y una baja sensibilidad a las condiciones de operación permite utilizar estos compuestos como material funcional. Por todo ello, la obtención de nuevos materiales nanoestructurados cerámica/carbono aparece como una opción muy interesante dada la creciente demanda que existe desde las industrias automovilística y aeronáutica. El objetivo de este trabajo es evaluar la influencia de las nanofibras de carbono (CNFs en el comportamiento mecánico y tribológico de los nanocompuestos de SiC/CNFs obtenidos mediante la técnica de spark plasma sintering. La caracterización tribológica realizada se ha basado en ensayos de deslizamiento en seco, mediante un

Effective conversion of maize straw wastes into bio-hydrogen by two-stage process integrating H2 fermentation and MECs.

Science.gov (United States)

Li, Yan-Hong; Bai, Yan-Xia; Pan, Chun-Mei; Li, Wei-Wei; Zheng, Hui-Qin; Zhang, Jing-Nan; Fan, Yao-Ting; Hou, Hong-Wei

2015-12-01

The enhanced H2 production from maize straw had been achieved through the two-stage process of integrating H2 fermentation and microbial electrolysis cells (MECs) in the present work. Several key parameters affecting hydrolysis of maize straw through subcritical H2O were optimized by orthogonal design for saccharification of maize straw followed by H2 production through H2 fermentation. The maximum reducing sugar (RS) content of maize straw reached 469.7 mg/g-TS under the optimal hydrolysis condition with subcritical H2O combining with dilute HCl of 0.3% at 230 °C. The maximum H2 yield, H2 production rate, and H2 content was 115.1 mL/g-TVS, 2.6 mL/g-TVS/h, and 48.9% by H2 fermentation, respectively. In addition, the effluent from H2 fermentation was used as feedstock of MECs for additional H2 production. The maximum H2 yield of 1060 mL/g-COD appeared at an applied voltage of 0.8 V, and total COD removal reached about 35%. The overall H2 yield from maize straw reached 318.5 mL/g-TVS through two-stage processes. The structural characterization of maize straw was also carefully investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) spectra.

Preparación y caracterización térmica y mecánica de mezclas PET-reciclado/Poliolefinas

OpenAIRE

Real, Magali

2009-01-01

Doble titulació Los compuestos con matriz polimérica son utilizados en las aplicaciones de la ingeniería porque tienen una baja densidad y buenas propiedades mecánicas. Pero no son utilizados a una gran escala porque son muy caros. La grande variedad de las matrices termoplásticas, que permite que experimentemos combinaciones con diversos tipos de de la resinas, se pueden considerar como alternativa. Estas matrices pueden ayudar a reducir coste y, al mismo tiempo, a aumentar...

Caracterización mecánica y a fractura de películas de LDPE y LDPE/PS

OpenAIRE

Faneca Llesera, Oscar

2004-01-01

El objetivo del siguiente estudio es la realización de un análisis sobre la influencia que tienen ciertas condiciones de procesamiento, como la relación de estirado y la altura de la línea de enfriamiento, sobre las propiedades mecánicas finales de películas de LDPE (Polietileno de Baja Densidad) y LDPE/PS (Polietileno de Baja Densidad/Poliestireno) obtenidas por extrusión por soplado. Para llevar a cabo el estudio se desarrollaron las siguientes tareas: - Preparación de una mezcla LDPE...

'Prevalence and antimicrobial susceptibility of Listeria monocytogenes and methicillin-resistant Staphylococcus aureus strains from raw meat and meat products in Zaria, Nigeria.

Science.gov (United States)

Ndahi, M D; Kwaga, J K P; Bello, M; Kabir, J; Umoh, V J; Yakubu, S E; Nok, A J

2014-03-01

The bacterial genera Listeria and Staphylococcus have been frequently isolated from food products and are responsible for a number of animal and human diseases. The aim of the study was to simultaneously isolate and characterize L. monocytogenes and Staphylococcus species from 300 samples of raw meat and meat products, to determine the susceptibility of the organisms to commonly used antimicrobial agents and to determine the presence of haemolysin A (hyl) virulence gene in L. monocytogenes and staphylococcal cassette chromosome mecA (SCCmec) gene in the Staph. aureus isolates using PCR. Of the 85 Listeria isolates tested, 12 L. monocytogenes were identified and tested for their sensitivity to 14 antimicrobial agents. All the 12 isolates (100%) were resistant to nine antimicrobial agents, but however sensitive to gentamicin. Only one isolate was found to harbour the hylA gene. Twenty-nine isolates were confirmed as Staph. aureus by the Microbact 12S identification system and were all presumptively identified as methicillin-resistant Staph. aureus species using oxacillin-resistant Staph. aureus basal medium (ORSAB). The 29 Staph. aureus isolates were tested for their sensitivity to 16 antimicrobial agents, and 11 were resistant to methicillin. None of the 11 Staph. aureus isolates harboured the methicillin resistance, mecA gene. Listeria monocytogenes and Staphylococcus aureus are important agents of foodborne diseases. Occurrence of these infectious agents was established in meat and meat products in Zaria, Nigeria. Majority of isolates obtained from this study, displayed multidrug resistance to commonly used antimicrobial agents, including methicillin resistance among the Staph. aureus isolates. The potential virulence of L. monocytogenes found in ready-to-eat food was documented by the carriage of hly A gene by one of the isolates. A different mechanism of methicillin resistance or different homologue of mec A gene may be circulating among Nigerian

Propriedades mecânicas do cimento ósseo e da poliuretana de mamona com e sem catalisador Mechanical properties of bone cement and castor oil-based polyurethane with and without a catalyst

Directory of Open Access Journals (Sweden)

A.F.M. Lima

2008-10-01

Full Text Available Avaliou-se o comportamento mecânico do polímero de mamona, tendo por variáveis o tempo de produção e a presença de catalisador, e utilizando como padrão comparativo o cimento ósseo (polimetilmetacrilato. Foram estabelecidos três grupos experimentais, de acordo com o tipo de corpo de prova (cilindro ou barra e polímero utilizado, que foram posteriormente subdivididos em subgrupos conforme o tempo após produção, ou seja, 24, 48 e 72 horas. O ensaio de compressão analisou a carga máxima e a tensão e o ensaio de dobramento estudou o módulo de dobramento e a resistência. Estatisticamente não houve diferenças nos valores de resistência à compressão ou ao dobramento às 24, 48 e 72 horas após a produção do polimetilmetacrilato e da poliuretana, com ou sem catalisador. A poliuretana com catalisador foi a mais resistente nos ensaios de compressão, apresentando módulo de dobramento semelhante ao do polimetilmetacrilato e resistência ao dobramento superior à da poliuretana sem catalisador. Conclui-se que: o tempo não alterou as propriedades mecânicas dos compósitos avaliados; o catalisador melhorou o desempenho mecânico da poliuretana de mamona; na resistência mecânica à compressão, a poliuretana com catalisador suportou mais carga que o polimetilmetacrilato.The mechanical properties of castor oil-based polyurethane was evaluated considering post-production time and the presence of a catalyst as variables and using bone cement (polymethylmetacrylate as a comparative pattern. According to proof body type (cylinders or bars and the used polymer, three experimental groups were established. Such groups were later subdivided according to post-production time, namely, 24, 48, and 72 hours. A compression assay analyzed maximum load and tension, and a folding assay evaluated the folding module and resistance. There were no statistical differences in the values for resistance to compression or folding at 24, 48, and 72 hours

Costo institucional del paciente con incapacidad temporal para el trabajo por lumbalgia mecánica. [Institutional cost of the patient with temporary inability to work due to mechanical low back pain

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María del Carmen Ponce Martínez

2013-10-01

Full Text Available In­tro­duc­ción La lumbalgia afecta de manera frecuente a la población económicamente activa. Es la primera causa de pérdida de días laborales en trabajadores menores de 55 años de edad y la segunda de ausentismo laboral. Objetivo Determinar el costo institucional del paciente con incapacidad temporal para el trabajo por lumbalgia mecánica. Material­ y­ métodos Se realizó un estudio de costos de expedientes de trabajadores con lumbalgia de 20 a 60 años con incapacidad temporal para el trabajo. El tamaño de la muestra (228 pacientes se calculó con la fórmula de promedios para población infinita con nivel de confianza del 95%. La técnica muestral fue por cuota empleando como marco muestral el listado de pacientes con incapacidad temporal para el trabajo y diagnóstico de lumbalgia mecánica. las variables estudiadas fueron las características sociodemográficas, el perfil de uso, costo unitario y costo promedio de los servicios otorgados. El análisis estadístico incluyó porcentajes, promedios, intervalo de confianza y proyección. Resultados El costo total promedio por paciente con lumbalgia mecánica es de 1744,08 uSD, la incapacidad es el costo más elevado (1083,71 uSD, seguido de los estudios de gabinete (394,89 uSD, las consultas (180,52 uSD, los medicamentos y el laboratorio. Conclusión El costo institucional del paciente con incapacidad temporal para el trabajo con lumbalgia mecánica resulta en miles de dólares y, proyectado a una población de pacientes, el costo se incrementa a millones.

Prevalência de transtornos psiquiátricos em portadores de prótese valvar mecânica com e sem febre reumática

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Regina Ponce da Silva

2011-01-01

Full Text Available OBJETIVO: Valvulopatias cardíacas, causadas por febre reumática e outras etiologias, podem levar ao implante de prótese valvar mecânica e anticoagulação oral obrigatória. Comorbidade psiquiátrica pode reduzir a adesão à anticoagulação. Esse estudo teve como objetivo avaliar a prevalência de transtornos psiquiátricos em pacientes com prótese valvar mecânica. MÉTODOS: Foram avaliados 193 portadores de prótese valvar mecânica, sendo 135 com cardiopatia reumática, tendo sido utilizada a Mini International Neuropsychiatric Interview, versão 5.0.0, para investigação quanto à presença de transtornos psiquiátricos. RESULTADOS: Foram encontrados os seguintes transtornos psiquiátricos nos pacientes avaliados: transtornos de ansiedade generalizada (16,6%, agorafobia (11,9%, fobia social (10,4%, depressão (9,8%, distimia (4,1% atual e 1% no passado, transtorno obsessivo-compulsivo (3,6%, pânico - vida inteira (1,6%, dependência ou abuso de substâncias (2%, dependência ou abuso de álcool (1%, episódio hipomaníaco (0,5% atual e 0,5% no passado, bulimia (0,5%. O risco de suicídio detectado foi de 13,4%. Ao ser comparada a prevalência dos transtornos no grupo com e sem cardiopatia reumática, não foi encontrada diferença estatisticamente significativa. CONCLUSÃO: Foi encontrada elevada comorbidade de transtornos psiquiátricos, principalmente transtornos ansiosos e depressão, sendo também elevado o risco de suicídio nessa população.

Influencia del proceso de fibrilación y desfibrilación enzimática en las propiedades mecánicas de hilos de fibras celulósicas regeneradas obtenidas por el proceso NMMO

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Carrillo, F.

2001-04-01

Full Text Available Fibre spinning from a solution of cellulose in N-methyl-morpholine-N-oxidehydrate is an environmentally friendly process (NMMO, which yields cellulose fibres with excellent mechanical properties. A special feature of these fibbers is their ability to fibrillate in the swollen state. It is possible to control and exploit fibrillation of this kind of fibre (generic name: lyocell through mechanical fibrillation and enzymatic defibrillation treatments. The mechanical properties (elongation at break. Young's modulus, tensile strenght and tenacity of solvent (NMMO-spun lyocell yarns samples have been studied in untreated condition as well as after industrial mechanical fibrillation and enzymatic defibrillation treatments. It is observed that the tenacity of lyocell yarn decreases greatly as a result of the treatments, particularly after the enzymatic treatment. For this reason, the control of these operations plays a critical role in ensuring acceptable mechanical properties of the yarns.

La obtención de fibras hiladas a partir de una solución de celulosa en N-óxido de N-metilmorfolina hidratado permite obtener fibras de celulosa regenerada, con excelentes propiedades mecánicas por medio de un proceso industrial no contaminante (proceso NMMO. Sin embargo, estas fibras presentan una propiedad especial, su elevada fibrilación, principalmente durante los tratamientos en húmedo, que es posible controlar y explotar mediante las etapas de fibrilación mecánica y desfibrilación enzimática de los productos fabricados. En el presente trabajo se estudiaron las propiedades mecánicas (deformación a la rotura, módulo de Young, resistencia máxima a la tracción y tenacidad de muestras de hilo de esta nueva fibra, evaluando la influencia de los tratamientos industriales de fibrilación mecánica y desfibrilación enzimática. Se observó que la tenacidad y la resistencia a la rotura de las muestras disminuyen significativamente después de estos

Planificación y optimización asistida por computadora de secuencias de ensamble mecánico // Computer aided Planning and optimization for mechanical assembly.

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L. L. Tomás-García

2009-01-01

Full Text Available El presente trabajo versa sobre la generación, planificación y optimización de secuencias deensamble mecánico a partir de su modelo geométrico tridimensional. Se soporta sobre un enfoqueque integra tanto información geométrica como restricciones tecnológicas del proceso deensamble. En el desarrollo de la misma quedó demostrado, que una vez conocido el modelogeométrico tridimensional de un ensamble, la aplicación de criterios tecnológicos y geométricos alproceso inverso de desensamble y su posterior tratamiento con el método de algoritmosevolutivos, genera una planificación optimizada del su proceso de ensamble mecánico. Laintegración de la información permite disminuir el número de secuencias a evaluar y de elementosa procesar, con lo que se evita la generación y evaluación de todas las secuencias posibles con laconsecuente disminución del tiempo de procesamiento. Como resultado de la aplicación delmodelo integrado propuesto, se obtiene la planificación del proceso de ensamble mecánico conuna reducción del tiempo de ensamble debido a que en las secuencias de ensamble obtenidas sereduce el número de cambios de dirección de ensamble, los cambios de herramientas y de puestosde trabajo, así como se minimiza la distancia a recorrer debido al cambio de puestos de trabajo.Esto se logra mediante un modelo de optimización multiobjetivo basado en algoritmos evolutivos.Palabras claves: ensamble mecánico, algoritmos genéticos, optimización multiobjetivo.____________________________________________________________________________AbstractThis work deals with the combinatorial problem of generating and optimizing feasible assemblysequences and doing the process planning involving tools and work places. The assembly sequencesare obtained from a 3D model of the assembled parts based on mating conditions along with a setof technological criteria, which allows automatically analyzing and generating the sequences. Thegenerated

Asistencia mecánica circulatoria de corta duración

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Lucía Doñate Bertolín

2016-10-01

Full Text Available El manejo conservador con inotrópicos y vasopresores en el shock cardiogénico ha mostrado ser insuficiente en muchos pacientes para mantener una perfusión adecuada y prevenir el fallo multiorgánico irreversible, lo que ha llevado a la mejora y a la utilización cada vez mayor de diferentes dispositivos de asistencia mecánica circulatoria de corta duración (balón intraaórtico de contrapulsación, TandemHeart, Impella, oxigenación de membrana extracorpórea [ECMO] y CentriMag Levitronix. Por ser la ECMO el dispositivo más versátil —capaz de proporcionar soporte a pacientes con fallo cardíaco, fallo respiratorio o fallo combinado cardiopulmonar durante días a semanas—, sus indicaciones se han ido diversificando, con un uso e interés en adultos creciente durante los últimos años, gracias también al progreso tecnológico y a la mejora en sus resultados. Es por ello esencial familiarizarse con la fisiología, las indicaciones, las estrategias de canulación, los principios de manejo y la evidencia sobre esta terapia, en la que enfatizaremos especialmente en esta revisión.

Detección precoz de hipoacusia neonatal no congénita en recién nacidos sometidos a ventilación mecánica en una unidad de neonatología de junio – septiembre 2012

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Díaz Torres, Mónica; Duque Cevallos, Sandra Marcela

2013-01-01

Introducción: La ventilación mecánica es una de las causas de hipoacusia en recién nacidos ingresados a una Unidad de Cuidados Intensivos Neonatales. Objetivo: Establecer el nivel de riesgo de los neonatos sometidos a ventilación mecánica de desarrollar hipoacusia no congénita en el Hospital Enrique Garcés de Quito durante Junio a septiembre del 2012. Sujeto: Se investigaron 101 pacientes que fueron Hospitalizados en la Unidad de Cuidados Intensivos Neonatales de los cuales el 20,79% re...

Whole genome analysis of a livestock-associated methicillin-resistant Staphylococcus aureus ST398 isolate from a case of human endocarditis

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van Strijp Jos AG

2010-06-01

Full Text Available Abstract Background Recently, a new livestock-associated methicillin-resistant Staphylococcus aureus (MRSA Sequence Type 398 (ST398 isolate has emerged worldwide. Although there have been reports of invasive disease in humans, MRSA ST398 colonization is much more common in livestock and demonstrates especially high prevalence rates in pigs and calves. The aim of this study was to compare the genome sequence of an ST398 MRSA isolate with other S. aureus genomes in order to identify genetic traits that may explain the success of this particular lineage. Therefore, we determined the whole genome sequence of S0385, an MRSA ST398 isolate from a human case of endocarditis. Results The entire genome sequence of S0385 demonstrated considerable accessory genome content differences relative to other S. aureus genomes. Several mobile genetic elements that confer antibiotic resistance were identified, including a novel composite of an type V (5C2&5 Staphylococcal Chromosome Cassette mec (SCCmec with distinct joining (J regions. The presence of multiple integrative conjugative elements combined with the absence of a type I restriction and modification system on one of the two νSa islands, could enhance horizontal gene transfer in this strain. The ST398 MRSA isolate carries a unique pathogenicity island which encodes homologues of two excreted virulence factors; staphylococcal complement inhibitor (SCIN and von Willebrand factor-binding protein (vWbp. However, several virulence factors such as enterotoxins and phage encoded toxins, including Panton-Valentine leukocidin (PVL, were not identified in this isolate. Conclusions Until now MRSA ST398 isolates did not cause frequent invasive disease in humans, which may be due to the absence of several common virulence factors. However, the proposed enhanced ability of these isolates to acquire mobile elements may lead to the rapid acquisition of determinants which contribute to virulence in human infections.

Estudio de las propiedades mecánicas y tribológicas de recubrimientos multicapa de espaciado sub-micrométrico

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Rodríguez, R. J.

2004-04-01

Full Text Available This work gathers a comparative study of the mechanical and tribological behaviour (microhardness under load, Young modulus, elasticplastic properties, friction and wear coefficients of TiN/CrN and TiN/AlTiN multilayers deposited by conventional industrial PVD techniques. PVD multilayers with about between 50 nm individual layer thickness were deposited on flat samples of Co-cemented WC achieving a total thickness of about 2 microns. Mechanical and Tribological tests include microhardness under load at final loads between 10 mN aand 750 mN, Young modulus calculations and friction and wear tests.

El presente trabajo recoge un estudio comparativo de las propiedades mecánicas y tribológicas (microdureza, fluencia, módulo elástico, coeficientes de fricción y desgaste, de multicapas TiN/AlTiN y TiN/CrN depositadas mediante técnicas industriales de PVD. Las capas, de espesores comprendidos entre 25nm y 100nm, se depositaron secuencialmente sobre substratos de WC, hasta obtener un espesor total de unas 2 micras. El estudio mecánico y tribológico comparativo incluyó ensayos de microdureza a cargas entre 10 mN y 750 mN, módulo elástico, comportamiento frente a fluencia y coeficientes de fricción y desgaste.

Upgrading of straw hydrolysate for production of hydrogen and phenols in a microbial electrolysis cell (MEC)

DEFF Research Database (Denmark)

Thygesen, Anders; Marzorati, Massimo; Boon, Nico

2011-01-01

In a microbial electrolysis cell (MEC), hydrolysate produced by hydrothermal treatment of wheat straw was used for hydrogen production during selective recovery of phenols. The average H2 production rate was 0.61 m3 H2/m3 MEC·day and equivalent to a rate of 0.40 kg COD/m3 MEC·day. The microbial...... the energy content in the consumed compounds and the cell voltage of 0.7 V. The highest hydrogen production was equivalent to 0.8 kg COD/m3 MEC·day and was obtained at pH 7–8 and 25°C. Accumulation of 53% w/v phenolic compounds in the liquor was obtained by stepwise addition of the hydrolysate during...

Caracterização físico-mecânica do laminado colado de bambu (Dendrocalamus giganteus.

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Juarez Benigno Paes

2009-09-01

Full Text Available Normal 0 21 MicrosoftInternetExplorer4 Esta pesquisa teve como objetivo avaliar a influência do tratamento preservativo e do tipo de adesivo nas propriedades físico-mecânicas do laminado colado, confeccionado com o bambu Dendrocalamus giganteus. Para tanto, colmos de bambu foram tratados pelo método de imersão em produto químico (solução de 1% de ingredientes ativos de borato de cobre cromatado - CCB e em água, durante 15 dias. Dos colmos tratados, foram retiradas as camadas externa e interna, obtendo-se lâminas com espessuras de 4 mm, comprimento de 45 cm e largura de 5 cm. Para a colagem das lâminas, utilizaram-se os adesivos "Cascophen RS" (resorcinol-formol e "Cascorez-Extra" (acetato polivinílico. O adesivo à base de resorcinol-formol proporcionou maior resistência à umidade ao BLC, quando comparado àquele à base de acetato polivinílico, tendo as amostras provenientes de peças tratadas com CCB sido mais estáveis que as tratadas com água. Dentre as propriedades mecânicas testadas, o adesivo apresentou resultado significativo para o cisalhamento na linha de cola e o tratamento preservativo para o MOE. A interação dos fatores adesivo e tratamento foi significativa para o MOE, resistência a compressão paralela ao cisalhamento na linha de cola, tendo as peças tratadas com água e aderidas com resorcinol-formol apresentado melhores resultados para o MOE e compressão paralela às fibras e aquelas tratadas com CCB, para o cisalhamento na linha de cola.

Mecánica Cuántica y Libre Albedrío: Cinco Cuestiones Fundamentales

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José Manuel Muñoz

2015-04-01

Full Text Available http://dx.doi.org/10.5007/1808-1711.2015v19n1p65 Este trabajo analiza críticamente la situación de la mecánica cuántica en las discusiones sobre el libre albedrío. Comienza describiendo cómo el principio de incertidumbre y el problema de la medición plantean un desafío al determinismo. A continuación, presenta las posiciones de apoyo y el rechazo de correlación entre los fenómenos y el libre albedrío cuántico. Por último,  pone todas estas cuestiones en el contexto de las cinco preguntas clave levantadas por Robert Kane: la compatibilidad, de significación, la inteligibilidad, la existencia y el la cuestión de determinismo.

Comportamiento mecánico del Polietileno Tereftalato (PET y sus aplicaciones geotécnicas

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Eduardo Botero Jaramillo

2014-01-01

Full Text Available Durante los últimos años la producción de residuos sólidos ha aumentado significativamente, causando problemas de salud y medio ambiente. Con el fin de plantear una alternativa para mitigar estos problemas, se investiga la reutilización de los envases de Polietileno-Tereftalato (PET como una sustitución de materiales ligeros convencionales utilizados en la nivelación o reemplazo de suelo. Para ello, se llevó a cabo una caracterización mecánica de los envases de PET más populares en el mercado de forma individual y grupal. Los resultados de las pruebas de compresión indican que los envases de PET exhiben resistencias de compresión que sugieren que estos se pueden aprovechar en la construcción de estructuras ligeras.

Estudo da Mecânica Cardíaca pelo Speckle Tracking

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Maria Cristina Donadio Abduch

2014-04-01

Full Text Available Speckles, ou marcadores naturais do miocárdio, originam se da interferência construtiva e destrutiva do feixe de ultrassom que incide sobre os tecidos, podem fornecer um diagnóstico precoce das alterações miocárdicas e atuar na predição de certos eventos cardíacos. Devido à sua relativa estabilidade temporal, os speckles podem ser rastreados durante o ciclo cardíaco por software dedicados, promovendo a análise da função sistólica e diastólica. São identificados tanto pela escala de cinza da ecocardiografia 2D convencional quanto pela ecocardiografia 3D, sendo independentes do ângulo de incidência do ultrassom, permitindo assim a avaliação da mecânica cardíaca nos três planos espaciais: longitudinal, circunferencial e radial. O objetivo do presente artigo é discutir o papel e o significado da deformação cardíaca obtida por meio do speckle tracking durante a avaliação da fisiologia cardíaca, e discutir as aplicações clínicas desta tecnologia ecocardiográfica inovadora.

Propuesta de un sistema de seguridad y salud ocupacional para una empresa del sector de mecánica automotriz

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UPC, Repositorio Academico; Rodríguez Páez, Nadya Leyla

2015-01-01

Se estudia la situación actual de una pequeña y mediana empresa (MYPE) que pertenece al sector de mecánica automotriz, la cual presenta el problema de sobrecostos por el incremento del número de accidentes y enfermedades ocupacionales. Ante esta situación, se propone establecer un sistema de gestión de seguridad y salud ocupacional que contribuya a disminuir el número de accidentes de trabajo y los sobrecostos ocasionados por ellos. Para ello, se deberá estudiar las actuales condiciones de lo...

Concreto leve com pérolas de EPS: estudo de dosagens e de características mecânicas

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Bianca Pereira Moreira Ozório

2016-01-01

Este trabalho teve como objetivo analisar o comportamento do concreto leve com pérolas de poliestireno expandido (expanded polystyrene – EPS), para posterior utilização em estruturas pré-moldadas constituídas, por exemplo, por painéis de paredes e lajes sujeitas a ações mecânicas. Também foram considerados parâmetros de durabilidade e mecanismos de redução da porosidade. Dentre um universo de solicitações a que as estruturas de concreto leve podem estar submetidas, analisaram-se, para d...

Estudios experimentales de los efectos mecánicos sobre la biología del cartílago de crecimiento

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Arriola, Forriol, F. F.

1998-01-01

El cartílago de crecimiento es la estructura encargada del crecimiento en longitud de los huesos largos. En el hombre los diferentes cartílagos de crecimiento cumplen su función durante un tiempo determinado hasta desaparecer. Cada cartílago de crecimiento tiene una velocidad de crecimiento y un tiempo de evolución determinado por factores que nos resultan desconocidos si bien se sabe que son tanto sistémicos como mecánicos. En este trabajo se presenta una revisión de trabajos experimental...

Complicaciones de la Ventilación Mecánica. Unidad de Cuidados Intensivos Pediátricos Holguín

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Carlos Alberto Córdova-Vega; Hèctor Pupo-Rodríguez; Andrés Andrés-Matos

2013-01-01

Se realizó un estudio prospectivo, descriptivo en pacientes ingresados en la Unidad de Cuidados Intensivos del Hospital Pediátrico de Holguín y que necesitaron ventilación mecánica por un tiempo mayor a las 24 horas, durante el año 2010, con el objetivo de conocer las complicaciones relacionadas con este proceder. Dentro de los resultados encontramos que las afecciones neurológicas (35,29%), las respiratorias y las malformaciones congénitas (17,64%) fueron las principales causas que llevaron ...

Eficacia de vibraciones transtorácicas más in-exuflación mecánica versus:técnicas manuales para tos asistida en pacientes pediátricos con parálisis cerebral grave o profunda

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Vergara Lozano, Pedro

2014-01-01

Las infecciones respiratorias recurrentes son frecuentes en la Parálisis Cerebral (PCI). La tos asistida manual (TAM) y mecánica (TM) persigue preservar las funciones del aparato respiratorio. Objetivo:. Evaluar la eficacia del tratamiento con vibraciones transtorácicas más insuflación-exuflación mecánica frente a las técnicas manuales, para inducir tos asistida en pacientes pediátricos con PCI grave o profunda. Método: 40 niños con PCI hospitalizados por infecciones respiratorias con edad me...

"Destinado de papel de impresión láser por medio magnético-mecánico".

OpenAIRE

Ramírez Valdovinos, Enrique

2011-01-01

El equilibrio ecológico y ambiental ha llegado a puntos críticos, causando consecuencias graves e irreversibles a nuestro entorno natural, debido al desarrollo industrial por parte de las grandes potencias mundiales, países en vías de desarrollo e incluso países del tercer mundo. La presente investigación, propone el uso de un nuevo equipo que genera fuerzas magnéticas-mecánicas para el destintado de la pulpa para la fabricación de papel, evitando con este equipo el uso de agentes químicos. E...

Normalización del cemento. Resistencias mecánicas: Algunos comentarios sobre el método de ensayo

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Gaspar Tebar, Demetrio

1980-03-01

Full Text Available Not avaible

Como es sabido la categoría de los distintos tipos y clases de los cementos del Pliego de Prescripciones Técnicas Generales para la Recepción de Cementos (RC-75 (1 viene fijada por la resistencia mecánica a compresión, en kp/cm², que como valor mínimo se exige a los 28 días al mortero normal, sin tener un límite máximo; criterio que se sigue en las normas de numerosos países.

Terceirização no setor de RH: estudo de casos em empresas do setor mecânico

OpenAIRE

Simone van der Halen

2000-01-01

Este trabalho procura investigar se a terceirização de alguns subsistemas de Recursos Humanos (RH), de empresas do setor metal-mecânico do Rio Grande do Sul, possibilita maior desenvolvimento e crescimento para as organizações e os funcionários. Contextualizou-se o tema, quando se abordou a flexibilização como resposta à globalização dos mercados, a terceirização, como ferramenta da flexibilização e aspectos referentes ao novo papel de RH e a terceirização neste setor. A pesquisa é de naturez...

Estudio de la viabilidad mecánica de tejidos poliméricos para trasplante de esófago

OpenAIRE

Valverde Fernández, Victoria

2016-01-01

La innovació a biomedicina és un fet que sempre ha d’estar present. Actualment, aquelles persones amb patologies a l’esòfag i en les que la única solució és el transplantament, com el càncer, es fa mitjançant parts de l’intestí gruixut o prim del mateix pacient. En aquest projecte s’estudien els aspectes mecànics de quatre polímers innovadors de la Amirkabir University of Technology de Teherán per a comprovar la seva viabilitat com a possibles substitutius d’esòfag humà. Per...

Propiedades mecánicas de aceites y grasas vegetales

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de Dios Alvarado, Juan

1995-10-01

Full Text Available Data of mechanical properties are presented for crude oils from avocado pulp, lupin grain, peanuts, soybean, sesame, cotton, castor-oil, linseed and passion fruit seeds; refined oils from sunflower, corn, peanut, olive and soybean; and cocoa, coconut, palm-oil and kernel palm-oil fats.
Correlation equations which describe the effect of temperature on the refractive index, density, viscosity and surface tension are obtained, and values of coefficient of expansion and activation energy for flow are calculated.

Se presentan los valores de las principales propiedades mecánicas determinadas en aceites crudos extraídos de pulpa de aguacate, granos o semillas de sésamo, algodón, altramuz o chocho, ricino, linaza, maní o cacahuete, maracuyá y soja; aceites refinados provenientes de semillas de girasol, germen de maíz, maní, oliva y soja; grasas extraídas de cacao, copra de coco, pulpa de palma africana y almendras de palma africana.
Con los datos experimentales se establecen ecuaciones de correlación que describen el efecto de la temperatura sobre el índice de refracción, la densidad, la viscosidad y la tensión superficial. En cada producto, con los datos de la densidad se calcula el coeficiente volumétrico de expansión térmica y con los de la viscosidad la energía de activación.

Desenvolvimentismo e pragmatismo: o ideário do MEC nos anos 1950 Developmentism and pragmatism: the ideas pursued by the Brazilian ministry of education in the 1950's

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Miriam Waidenfeld Chaves

2006-12-01

Full Text Available Este artigo tem como objetivo mostrar como o desenvolvimentismo e o pragmatismo, dois pensamentos de natureza distinta, contribuem, cada um à sua maneira, para fundamentar uma política de reconstrução nacional nos anos 1950, em particular no âmbito do Ministério da Educação e Cultura - MEC. A idéia central é que, por circularem nos mesmos espaços institucionais, esses dois pensamentos acabam por interagir um com o outro, de tal modo que a ideologia desenvolvimentista se transforma em um solo fértil para a retomada e expansão do pragmatismo. Para explicar esse fenômeno, recorda-se que ambos se ancoram em uma concepção de cunho prático baseada na política. Chama-se a atenção para a maneira como o Instituto Superior de Estudos Brasileiros - Iseb - e o Instituto Nacional de Estudos Pedagógicos - Inep -, dois órgãos do MEC responsáveis por fomentar um pensamento nacional, se apropriam desses ideários para a formulação e a implementação de políticas de reconstrução nacional.This paper aims to discuss how two distinct definitional concepts - developmentism and pragmatism - contributed, in their own particular ways, to the underlying foundations upon which a national reconstruction policy was implemented in the 1950's. Special consideration shall be given to the fact that their unruffled co-existence within the very same institution - the Brazilian Ministry of Education (MEC - turned the developmentist ideology into a fertile ground for the rebirth and growth of pragmatism. Upon such consideration, this paper shall highlight (1 the fact that both concepts are based upon an eminently practical political mindset and (2 the means employed by ISEB (Higher Institute of Brazilian Studies and INEP (National Institute of Pedagogical Studies to develop and implement national reconstruction policies. These institutions were institutions within MEC whose think-tank board members aimed at scaffolding the national frame of thinking.

Algunas propiedades físico-mecánicas y de trabajabilidad de la Acacia melanoxylon

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Elliot Correcha R.

1984-01-01

Full Text Available El presente artículo muestra los resultados obtenidos de las propiedades físicas como: gravedad especifica anhidra, seca al aire y en estado verde; densidad verde, seca al aire, anhidra y básica; y contracciones radial, tangencial y volumétrica. Propiedades mecánicas tales como: flexión estática en estado verde y seca al aire, compresión paralela al grano en estado verde y seca al aire. Además ensayos de trabajabilidad de cepillado, moldurado, taladrado y torneado de la Acacia melanoxylon. Se usaron metodologías establecidas por ASTM, ICONTEC y COPANT. Estos ensayos se realizaron en los laboratorios del Instituto de Ensayos e Investigación (IEI de la facultad de Ingenleria, Universidad Nacional de Bogotá.

Alterações estruturais e mecânicas de solo de várzea cultivado com arroz irrigado por inundação

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Marcelo Ivan Mentges

2013-02-01

Full Text Available A conversão de área natural para área de uso agrícola pode degradar a estrutura do solo, favorecendo a ocorrência de compactação. Este trabalho teve por objetivo avaliar as alterações nas propriedades físico-hídricas e mecânicas de um Gleissolo Háplico provocadas pela conversão de um campo natural antropizado para área de cultivo de arroz irrigado. Propriedades físico-hídricas (densidade, porosidade total, macro e microporosidade, índice de vazios e retenção de água e mecânicas (pressão de preconsolidação, índice de compressão, coeficiente de descompressão e índice de recuperação foram avaliadas nos horizontes A1 (0,0-0,25 m, A2 (0,25-0,51 m, Cg1 (0,51-0,92 m e Cg2 (0,92-1,20+ m em solo sob campo antropizado sem uso agrícola e nos horizontes Ap (0,0-0,17 m, A (0,17-0,40 m, Cg1 (0,40-0,70 m e Cg2 (0,70-1,00+ m, em solo cultivado com arroz irrigado. Oito anos de cultivo de arroz sob preparo convencional e irrigação por inundação não alteraram significativamente as propriedades físico-hídricas e mecânicas, de acordo com a análise de agrupamentos. Porém, o cultivo de arroz aumentou a densidade do solo e reduziu o índice de vazios, a porosidade total e a macroporosidade. A relação da elasticidade com a densidade do solo, a porosidade total e o índice de vazios foi influenciada pelo tipo de estrutura, pois maiores compressões e descompressões ocorreram nos horizontes de estrutura prismática, em comparação aos horizontes de estrutura maciça.

Gestão da biblioteca universitária: análise com base nos indicadores de avaliação do MEC

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Luiz Cláudio Gomes Maia

Full Text Available O objetivo deste artigo é compreender como os gestores do Sistema de Bibliotecas da UFG (Sibi/UFG utilizam os indicadores de avaliação do MEC durante o processo de aquisição de recursos informacionais. A investigação foi realizada por meio de entrevistas semiestruturadas e analisadas de forma descritiva, por meio de um estudo de caso a partir do qual se buscou interpretar as informações, tendo como base o referencial teórico que norteou o desenvolvimento da pesquisa, com os gestores das bibliotecas e com os bibliotecários gerentes de atendimento. Os resultados apontam que há uma homogeneidade acerca do processo de avaliação e que a biblioteca precisa definir, junto ao corpo docente, e a administração da Instituição, uma Política de Formação de Acervo que deverá orientar o processo de aquisição de materiais bibliográficos nos diversos formatos, tanto para cursos existentes quanto para novos. Contribuindo, dessa forma, para um melhor atendimento às novas diretrizes estabelecidas pelo MEC e, consequentemente, resultando em melhorias para a biblioteca universitária.

Medial Entorhinal Cortex Lesions Only Partially Disrupt Hippocampal Place Cells and Hippocampus-Dependent Place Memory

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Jena B. Hales

2014-11-01

Full Text Available The entorhinal cortex provides the primary cortical projections to the hippocampus, a brain structure critical for memory. However, it remains unclear how the precise firing patterns of medial entorhinal cortex (MEC cells influence hippocampal physiology and hippocampus-dependent behavior. We found that complete bilateral lesions of the MEC resulted in a lower proportion of active hippocampal cells. The remaining active cells had place fields, but with decreased spatial precision and decreased long-term spatial stability. In addition, MEC rats were as impaired in the water maze as hippocampus rats, while rats with combined MEC and hippocampal lesions had an even greater deficit. However, MEC rats were not impaired on other hippocampus-dependent tasks, including those in which an object location or context was remembered. Thus, the MEC is not necessary for all types of spatial coding or for all types of hippocampus-dependent memory, but it is necessary for the normal acquisition of place memory.

Ventilación mecánica no invasiva y oxigenoterapia de alto flujo en el tratamiento de la insuficiencia respiratoria

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Molinero Herrero, Nuria

2017-01-01

Trabajo de fin de Grado. Grado en Enfermería (Zamora). Curso académico 2016/2017 [ES]La enfermedad obstructiva crónica (EPOC) está incluida en las enfermedades que pueden asociar a insuficiencia respiratoria. El tratamiento de soporte ventilatorio de elección es la ventilación mecánica no invasiva (VMNI) por las múltiples ventajas que ofrece. Actualmente se está desarrollando el uso de la oxigenoterapia de alto flujo (ONAF) en pacientes con insuficiencia respiratoria hipoxémica...

Caracterização fenotípica da resistência a antimicrobianos e detecção do gene mecA em Staphylococcus spp. coagulase-negativos isolados de amostras animais e humanas Phenotypic characterization of antimicrobial resistance and detection of the mecA gene in coagulase-negative Staphylococcus spp. isolates from animal and human samples

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Lidiane de Castro Soares

2008-08-01

Full Text Available Os estafilococos coagulase-negativos (ECN fazem parte da microbiota normal da pele e, apesar de terem sido considerados saprófitas por muito tempo, o seu significado clínico como agente etiológico tem aumentado com o passar dos anos. Neste estudo, foram obtidos 72 isolados de ECN a partir de amostras do conduto auditivo de cães, de mastite bovina e de infecções humanas. Staphylococcus xylosus foi o microrganismo mais isolado, nas amostras animais, e S. cohnii subsp. cohnii em humanos. Os isolados foram avaliados de modo a traçar o perfil fenotípico de sua resistência aos antimicrobianos mais indicados no tratamento de infecções estafilocócicas. Foi detectado um elevado nível de resistência à penicilina e ampicilina. A gentamicina, a vancomicina e a associação ampicilina+sulbactam foram eficientes frente aos isolados testados. A resistência à oxacilina foi avaliada por meio dos testes de difusão em disco modificada, ágar screen, microdiluição em caldo e diluição em ágar para constatar, se à semelhança do que ocorre com os estafilococos coagulase-positivo, esta pode ser mediada pelo gene mecA e apresentada de forma heterogênea. A presença do gene mecA foi determinada pelo método da Reação em Cadeia de Polimerase (PCR, sendo 5,6% dos isolados mecA positivos.Coagulase-negative staphylococci (SCN make part of the normal microbiota skin and although they have been considered saprophytics for years, nowadays their clinical significance as an etiologic agent has increased. In this study, 72 SCN isolates obtained from external ear canals of dogs, bovine mastitis and human nosocomial infections were evaluated. Staphylococcus xylosus was the most prevalent microorganism in animal samples and S. cohnii subsp. cohnii in human samples. SCN isolates were evaluated in order to establish a phenotypical resistance pattern towards the most indicated antibiotics for staphyloccocal infections. A high level of resistance to penicillin

Evolução e característica de lactantes com bronquiolite viral aguda submetidos à ventilação mecânica em uma unidade de terapia intensiva pediátrica brasileira Outcome and characteristics of infants with acute viral bronchiolitis submitted to mechanical ventilation in a Brazilian pediatric intensive care

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Fernanda Umpierre Bueno; Jefferson Pedro Piva; Pedro Celiny Ramos Garcia; Patrícia Miranda Lago; Paulo Roberto Einloft

2009-01-01

OBJETIVO: Descrever as características e a evolução de lactantes com bronquiolite aguda submetidos à ventilação mecânica. MÉTODOS: Estudo retrospectivo desenvolvido entre março 2004 e setembro 2006 (três invernos consecutivos), recrutando todos os lactantes (menos de 12 meses de idade) com diagnóstico de bronquiolite viral aguda e submetidos à ventilação mecânica em uma unidade de terapia intensiva, brasileira, ligada a uma universidade. Os parâmetros de ventilação mecânica adotados no 1°, 2°...

Seguimiento a mediano plazo de pacientes sometidos a reemplazo valvular aórtico con prótesis mecánicas

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Ricardo G. Marenchino

2008-01-01

Full Text Available RESUMENIntroducción La patología de la válvula aórtica es una de las causas más frecuentes de reemplazo valvular en nuestro medio. La falta de información actualizada sobre la evolución alejada de pacientes que recibieron prótesis mecánicas en posición aórtica motivó la realización del presente estudio.ObjetivoConocer la mortalidad, la morbilidad (complicaciones mayores y los resultados funcionales (mejoría clínica durante el seguimiento de pacientes portadores de una válvula mecánica en posición aórtica.Material y métodosSe seleccionaron 95 pacientes sometidos a reemplazo valvular aórtico con prótesis mecánicas.Todos los pacientes fueron operados entre enero de 1999 y diciembre de 2006. La media de seguimiento fue de 4,5 ± 2,3 años, percentiles 25-75: 2,5-6,3 años. El seguimiento total fue de 427,5 pacientes/año.ResultadosLa media de edad fue de 64,5 ± 12,3 años y el 61,1% de los pacientes eran de sexo masculino.Sesenta pacientes (63% estaban en clase funcional (CF III-IV antes de la cirugía.En el seguimiento, 67 pacientes (70,5% se encuentran en CF I y 28 (29,5% en CF II. No se observaron pacientes en CF III ni IV.La media del índice área valvular efectiva / área de superficie corporal fue de 1,06 cm2/m2.La supervivencia actuarial (Kaplan-Meier fue del 95% (IC 95% 88-98% a un año y del 89% a los 5 años (IC 95% 76-95%. La mortalidad relacionada se registró en 9 pacientes (9,5%. La incidencia de tromboembolia fue del 0,2% paciente-año, la de hemorragia del 2,3% paciente- año y la de endocarditis del 0,7% paciente-año. La tasa de reoperación fue del 0,4% paciente-año.ConclusionesLos resultados obtenidos fueron similares a los comunicados en series internacionales en términos de supervivencia y complicaciones mayores. La frecuencia de eventos adversos observados a mediano plazo, como en todo el mundo, aún permanece elevada.

Comportamiento mecánico y dinámico de una mezcla asfáltica con adición de fibras

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Oscar Javier Reyes Ortiz

2005-01-01

Full Text Available El artículo refiere el análisis experimental en el laboratorio, del efecto de la adición de fibras de polipropileno por vía seca (reemplazo de material granular por fibra sobre las propiedades mecánicas y dinámicas de una mezcla. Inicialmente se caracteriza el material granular y asfalto CA60/70, se realiza el diseño de la mezcla asfáltica de granulometría 0/10 (IDU RSV 2002 y asfalto de acuerdo con la metodología Marshall; se evalúa el efecto de fibras sobre las propiedades mecánicas mediante la evaluación de la estabilidad y fluencia, y dinámicamente por su valor de deformación permanente y modulo dinámico. Los resultados muestran un efecto positivo de las fibras en la modificación de la mezcla asfáltica. El modulo dinámico aumenta en un 45% promedio en un porcentaje de adición de 0.60%; la deformación permanente disminuye en 27.6% para una adición de fibras de 0.60% y 48.8% para la adición de fibras de 0.75%, respectivamente. Este comportamiento refleja otra alternativa eficaz para mejorar la mezcla asfáltica, aumentando la resistencia a la disgregación por efecto abrasivo del tráfico y retardando el inicio y propagación del agrietamiento por ahuellamiento

Ventilação mecânica não invasiva na crise de asma aguda grave em crianças: níveis de evidências

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Paula de Souza Silva

2015-12-01

Full Text Available RESUMO Objetivo: Avaliar a qualidade das evidências existentes para embasar diretrizes do emprego da ventilação mecânica não invasiva no manejo da crise de asma aguda grave em crianças não responsivas ao tratamento padrão. Métodos: Busca, seleção e análise de todos os artigos originais sobre asma e ventilação mecânica não invasiva em crianças, publicados até 1º de setembro de 2014, em todos os idiomas, nas bases de dados eletrônicas PubMed, Web of Science, Cochrane Library, Scopus e SciELO, encontrados por meio de busca pelos descritores "asthma", "status asthmaticus", "noninvasive ventilation", "bronchospasm", "continuous positive airway pressure", "child", "infant", "pediatrics", "hypercapnia", "respiratory failure", e das palavras-chave "BIPAP", "CPAP", "bilevel", "acute asthma" e "near fatal asthma". Os artigos foram qualificados segundo os graus de evidências do Sistema GRADE. Resultados: Foram obtidos apenas nove artigos originais. Destes, dois (22% apresentaram nível de evidência A, um (11% apresentou nível de evidência B e seis (67% apresentaram nível de evidência C. Conclusão: Sugere-se que o emprego da ventilação mecânica não invasiva na crise de asma aguda grave em crianças não responsivas ao tratamento padrão é aplicável à maioria desses pacientes, mas as evidências não podem ser consideradas conclusivas, uma vez que pesquisa adicional de alta qualidade provavelmente tenha um impacto modificador na estimativa de efeito.

Influencia de la atmósfera de sinterización en las propiedades mecánicas de los aceros P/M AISI 430L

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Iglesias, F. Javier

2014-03-01

Full Text Available It has studied the stainless steel powder metallurgy AISI 430L. It has compared the sintering in two different atmospheres; in vacuum, and in an atmosphere containing nitrogen. It has developed a heat treatment with the aim of improving the mechanical properties. This has been done through microstructural modification of complex nitrides of iron and chromium precipitates during the phase of sintering. Physical properties have been evaluated and are been performing a microstructural analysis for microstructure related to the increase in mechanical properties.Se ha estudiado el acero inoxidable pulvimetalúrgico AISI 430L, comparando la sinterización en dos atmósferas diferentes; en vacío, y en una atmósfera que contiene nitrógeno. Se ha desarrollado un tratamiento térmico con objeto de incrementar las propiedades mecánicas, mediante la modificación microestructural de los nitruros complejos de hierro y cromo precipitados durante la etapa de sinterización. Se han evaluado las propiedades físicas y a la vez se ha realizado un análisis microestructural con el fin de relacionar la microestructura con el incremento en las propiedades mecánicas.

Qualidade das chapas de partículas aglomeradas fabricadas com resíduos do processamento mecânico da madeira de Pinus elliottii (Engelm..

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Lourdes Patricia Elias Dacosta

2010-08-01

Full Text Available Este trabalho teve como objetivo avaliar as propriedades mecânicas de chapas de madeira aglomerada, confeccionados com resíduos de Pinus elliottii Engelm., resultantes do processamento mecânico da madeira. As chapas foram produzidas com dois tipos de resíduos, cavaco e maravalha, utilizados puros ou misturados. O adesivo utilizado foi à base de uréia-formaldeído em proporções de 4, 8 e 12% com base no peso seco das partículas de madeira, e as densidades nominais das chapas foram de 0,6 e 0,7 g/cm3. Foram avaliadas as propriedades de flexão estática, ligação interna e arrancamento de parafuso. Os valores das propriedades de flexão estática aumentaram com a proporção de maravalha, com a densidade da chapa, e com o teor de adesivo. Pode-se concluir que, usando as partículas do tipo maravalha, misturadas com maiores percentagens de adesivo e maiores densidades, são obtidas chapas com qualidade satisfatória.

Resumen del II Congreso Latinoamericano de Estudiantes de Ingeniería Mecánica y Metalurgia. // Summary of the 2nd Latin-American Congress for Students of Mechanical Engineering.

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D. William Fonseca

2003-09-01

Full Text Available Del 15 al 20 de Septiembre del 2003 se celebró el II Congreso Latinoamericano de Estudiantes de Ingeniería Mecánica y Metalurgia,CLEIM´2003, con sede en el Hotel Costa Azul de la Villa Panamericana y el Instituto Superior Politécnico José Antonio Echeverría,CUJAE., con el auspicio de la Facultad de Ingeniería Mecánica de la CUJAE y el Centro de Estudios de Innovación y Mantenimiento(CEIM y la colaboración y patrocinio de DHL, Los Portales S.A, Unión de Empresas de Recuperación de Materias Primas, TractoImport, CUBACEL, Movitel, Softel, Centro de Ingeniería Genética y Biotecnología, Ministerio de Cultura, Departamento deTelemática de la Facultad de Eléctrica, Universitur- CUJAE, Unidad de Eventos de Islazul.y LabioFam. El CLEIM fue organizadopor la Federación Estudiantil Universitaria de la Facultad de Ingeniería Mecánica de la CUJAE en coordinación para su promocióncon la Coordinadora Latinoamericana de Estudiantes de Ingeniería Mecánica y Metalurgia, CLEIM. Este informe resume lasprincipales actividades realizadas durante este congreso y los resultados obtenido durante el mismo.___________________________________________________________________________AbstractThe 2nd Latin-American Congress for Students of Mechanical Engineering (CLEIM 2003 was celebrated in the areas of theHigher Polytechnic Institute José Antonio Echeverría and the Costa Azul Hotel, on September 15 - 20 of 2003, sponsored byMechanical Engineering Faculty at CUJAE and Center for Studies of Maintenance (CEIM. This Congress was organized bythe Federation of Students (FEU in the Faculty of Mechanical Engineering at CUJAE in coordination and promotion with theLatin American Coordinator of Mechanical Engineering and Metallurgy Students (CLEIM. This event was protagonist, onceagain, for the union of the great Mechanical Engineers community in Latin-American area with the mission of developing thisprofession with genius, creativity and talent. After an

Methicillin-resistant Staphylococcus aureus isolates from Iranian ...

African Journals Online (AJOL)

Methicillin-resistant Staphylococcus aureus isolates from Iranian restaurant food samples: Panton-Valentine Leukocidin, SCCmec phenotypes and antimicrobial resistance. ... TetK (80.72 %), linA (67.46 %), aadA1 (62.65 %), and msrA (55.42 %) were the most frequently identified resistance genes. SCCmec V (57.83%) ...

Efeito de diferentes graus de dano mecânico na qualidade fisiológica de sementes de sorgo Effect of different mechanical damage degrees in sorghum seeds

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Dea Alecia Martins netto

1999-08-01

Full Text Available Diversas amostras de sementes de sorgo (Sorghum bicolor L. Moench., cultivar BR 303, com diferentes níveis de danos mecânicos, foram analisadas com o objetivo de determinar o efeito imediato de danos mecânicos sobre a qualidade fisiológica. Os percentuais de dano mecânico foram determinados pelo teste de verde rápido, e a qualidade fisiológica das sementes pelos testes de germinação, envelhecimento acelerado, teste de frio, índice de velocidade de emergência e população inicial de plântulas. O experimento foi conduzido no Laboratório de Análises de Sementes da Embrapa-Centro Nacional de Pesquisa de Milho e Sorgo (CNPMS, em Sete Lagoas, MG. Através da análise de regressão, verificou-se que houve redução significativa da germinação e do vigor quando as sementes apresentaram até 5% de dano; de 5% a 15% de dano a redução na qualidade fisiológica não foi significativa. Acima de 15% até 23% de dano a germinação e o vigor sofreram um decréscimo de 22,5%, em comparação com o controle. O efeito prejudicial imediato dos danos mecânicos sobre a qualidade fisiológica das sementes de sorgo pôde ser detectada pelos testes aplicados.Twelve seed lots of sorghum (Sorghum bicolor L. Moench., cultivar BR 303, with different degrees of mechanical damage were evaluated on germination and vigor test. The data of mechanical damage based upon fast green test, accelerating aging, cold test, speed of emergence and stand establishment. The experiment was conducted in Seed Laboratory Analysis of the Embrapa-Centro Nacional de Pesquisa de Milho e Sorgo (CNPMS, in Sete Lagoas, MG, Brazil. There were significantly decrease through regressions analysis on germination and vigor tests, when the seeds were damaged up to 5%; from 5% to 15% of damage the decrease was not significant. From 15% to 23% of damage, the germination and vigor declined 22.5% compared to the control. The immediate hazard effect of mechanical damages on physiological

Análisis combinado acústico-mecánico durante el almacenamiento de cebolla (allium fistulosum) mínimamente procesada

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Andrea González; Gabriela Cáez; Fabián Moreno; Natalia Rodríguez; Indira Sotelo

2012-01-01

La cebolla de rama (Allium fistulosum) es una hortaliza altamente perecedera debido a su contenido de humedad, a su elevada tasa metabólica y al deficiente manejo poscosecha al cosecharla y transportarla. El objetivo de esta investigación fue determinar la relación entre el deterioro visual del producto y los cambios generados en las propiedades mecánicas y acústicas del mismo. Se utilizó cebolla de rama cultivada en Aquitania, Boyacá Colombia, sometida a condiciones: empaque a vacío (10 mbar...

Efecto de la música sobre la ansiedad y el dolor en pacientes con ventilación mecánica

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Sanjuán Naváis, M.; Via Clavero, G. (Gemma); Vázquez Guillamet, B.; Moreno Durán, A.M.; Martínez Estalella, Gemma

2013-01-01

La capacidad de la música para aliviar la ansiedad o el dolor ha sido utilizada ampliamente a lo largo de la historia. Objetivo: Examinar los efectos de la música sobre la ansiedad y el dolor en pacientes con ventilación mecánica invasiva. Diseño: Un ensayo aleatorizado controlado con medidas repetidas. Material y método: estudio prospectivo experimental con distribución aleatoria, en un hospital universitario de tercer nivel, de enero de 2009 a junio de 2010. La muestra fue de 44 participant...

Análise hidro-mecânica da barragem de terra e enrocamento UHE emborcação

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Rocha, Daniel de Oliveira

2007-01-01

Esta pesquisa apresenta os resultados das análises acopladas de equilíbrio e fluxo (tensãodeformação- poropressão) em 3 dimensões (3D) da barragem UHE Emborcação, de propriedade da Companhia Energética de Minas Gerais. Na tentativa de avançar nos estudos do comportamento mecânico e hidráulico da barragem de terra e enrocamento da UHE Emborcação, realizaram-se os estudos divididos em três partes: análise da influência da anisotropia na permeabilidade na fase construção, análise ...

Análisis mecánico por elementos finitos de una antena UHF en la órbita de Marte

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Moreno García, Carlos

2015-01-01

El proyecto desarrolla el diseño mecánico de una antena helicoidal en banda UHF que será parte de un satélite cuyo destino final será Marte. Los principales objetivos de la misión son: Buscar trazas o evidencia de metano y otros gases atmosféricos que podrían manifestar signos de procesos biológicos o geológicos activos, es decir, buscar indicios de vida pasada en Marte Poner a prueba la tecnología necesaria para posteriores misiones europeas a Marte. El proyecto se centrará en la...

Estimation of mechanical properties of rock using artificial intelligence Estimación de propiedades mecánicas de roca utilizando inteligencia artificial

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César Augusto Ochoa

2011-12-01

Full Text Available This paper discusses how two artificial intelligence techniques were combined, neural networks and genetic algorithms for the development of a computational tool used for the estimation of mechanical properties such as tensile strength, uniaxial compressive strength and triaxial compressive strength in sandstones, from petrophysical properties using data from tests of Rock Mechanics Laboratory of the Colombian Petroleum Institute - Ecopetrol SA as training data, to improve the design of non-destructive testing with some degree of confidence and resulting in cost reduction.Este artículo presenta la forma como fueron combinadas dos técnicas de inteligencia artificial, redes neuronales y algoritmos genéticos, para el desarrollo de una herramienta computacional utilizada para la estimación de propiedades mecánicas tales como la resistencia a la tensión, la resistencia a la compresión uniaxial y la resistencia a la compresión triaxial en areniscas, a partir de propiedades petrofísicas utilizando datos de pruebas del Laboratorio de Mecánica de Rocas del Instituto Colombiano del Petróleo - Ecopetrol S.A. como datos de entrenamiento facilitando el diseño de ensayos no destructivos con cierto grado de confianza y dando lugar a una reducción de costos.

Modificación de las propiedades ópticas y mecánicas de polímeros mediante implantación iónica

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Rodríguez, R. J.

2000-08-01

Full Text Available This paper gathers the studies of the effects introduced when Nitrogen and Silicon were implanted in policarbonates used in optical applications. Different Nitrogen and Silicon doses were implanted for finding out the roles of this parameter in the mechanical and optical modifications. Several mechanical tests were carried out, like Microindentation, Nanoindentation and AFM. IR and UV-VIS optical tests were also carried out. Results show harder surfaces for the high Nitrogen implanted doses, and great changes in the UV-VIS spectrums.

En el presente trabajo se estudian los efectos introducidos por la implantación de Nitrógeno atómico y Silicio sobre probetas de policarbonato empleadas para usos ópticos. Distintas dosis de Nitrógeno y Silicio fueron implantadas de cara a poner de manifiesto el efecto de la dosis sobre las propiedades ópticas y mecánicas. Se llevaron a cabo ensayos mecánicos de microdureza, nanodureza, y AFM, así como ensayos ópticos de Reflexión-absorción IR y Transmitancia UV-VIS. Los resultados muestran un endurecimiento superficial para las implantaciones a dosis altas de Nitrógeno, así como cambios considerables en los espectros de transmitancia.

Efeitos de técnicas de desobstrução brônquica na mecânica respiratória de neonatos prematuros em ventilação pulmonar mecânica Results of airway clearance techniques in respiratory mechanics of preterm neonates under mechanical ventilation

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Mara Lisiane de Moraes dos Santos

2009-06-01

Full Text Available OBJETIVOS: O objetivo do trabalho foi avaliar as repercussões de técnicas fisioterapêuticas específicas na resistência média de vias aéreas e na complacência dinâmica de neonatos pré-termo em ventilação pulmonar mecânica. MÉTODOS: Dezoito neonatos pré-termo em ventilação pulmonar mecânica convencional foram submetidos a uma sessão de fisioterapia respiratória (compressão torácica manual durante a expiração + aspiração da cânula intratraqueal. Medidas de resistência média de vias aéreas e complacência dinâmica foram realizadas antes, 10, 40 e 70 minutos após as intervenções, por meio de um pneumotacógrafo com monitor gráfico (NewPort Navigator GM-250®, acoplado a um transdutor de fluxo (Varfley-Bicore®. Para análise dos resultados, os neonatos pré-termo foram divididos em dois grupos: tempo de ventilação pulmonar mecânica 5 dias. Os resultados foram analisados pelo teste Friedman e pós-teste de Dunn de múltiplas comparações (p5 dias a resistência média de vias aéreas reduziu no 10º(p5 dias, com melhores respostas na resistência média de vias aéreas.OBJECTIVES: This research aimed to evaluate the repercussions of specific chest physiotherapy procedures in mean airway resistance and in dynamic compliance in preterm infants in mechanical ventilation. METHODS: Eighteen preterm infants in conventional mechanical ventilation were submitted to one session of chest physiotherapy (manual chest compression during expiration + intermittent aspiration of intratracheal cannula. Mean airway resistance and dynamic compliance measurements were taken prior to, 10, 40 and 70 minutes after intervention using a pneumotachograph with graphic display (Newport Navigator GM-250®, coupled to a flow transducer (Varfley-Bicore®. For analysis of results the infants were divided into 2 groups; less than 5 days (group mechanical ventilation 5 on mechanical ventilation. Values were analyzed by Friedman Test, with Dunn

High prevalence of methicillin-resistant coagulase-negative staphylococci isolated from a university environment in Thailand.

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Seng, Rathanin; Leungtongkam, Udomluk; Thummeepak, Rapee; Chatdumrong, Wassana; Sitthisak, Sutthirat

2017-06-01

The present study was conducted to isolate and characterize the molecular epidemiology of the methicillin-resistant staphylococci in the general university environment, where all five locations; the library, restrooms, canteens, computer rooms and outdoor surfaces, are in common use by a large population of students. We used Mannitol Salt Agar (MSA) supplemented with 4 μg/ml of oxacillin to screen the methicillin-resistant staphylococci. The species level was identified by PCR of rdr (Staphylococcus epidermidis), groESL (Staphylococcus haemolyticus) and nuc (Staphylococcus aureus and Staphylococcus warneri) genes and DNA sequencing of tuf and dnaJ genes. The susceptibility patterns of the isolates were determined using the disk diffusion method. Antibiotic and disinfectant resistance genes, together with SCCmec types, were detected by the PCR method. The methicillin resistant-staphylococci were isolated from 41 of 200 samples (20.5%), and all of them were found to be methicillin-resistant coagulase negative staphylococci (MR-CoNS). The library had the highest percentage of contamination, with 43.3% of the samples found to be contaminated. All isolates belonged to 6 different species including S. haemolyticus, S. epidermidis, S. warneri, S. cohnii, S. saprophyticus and S. hominis. The antimicrobial resistance rates were highest against penicillin (100%), then cefoxitin (73.1%), erythromycin (73.1%) and oxacillin (68.3%). Altogether, the isolates were approximately 61.0% multidrug resistant (MDR), with the S. epidermidis isolates being the most multidrug resistant. The prevalence of the qacA/B gene was detected in 63.4% of the isolates, and SCCmec could be typed in 43.9% (18/41) of the isolates. The type range was: II (n = 1), IVd (n = 1), I (n = 2), V (n = 6), IVa (n = 8) and untypeable (n = 23). This result indicates that these university environments are contaminated with methicillin-resistant coagulase negative staphylococci that carry various SCCmec types and

Propiedades mecánicas de las uniones por láser de aceros inoxidables dúplex

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Amigó, V.

2005-04-01

Full Text Available The welded joints of stainless steels always present problems for the microstructural modifications that occur in the heat affected zone. Particularly, duplex stainless steels present very important changes when the weld pool solidifies forming fundamentally ferritic structures with some austenite in grain boundaries. These microstructural modifications, and those which occur in the HAZ, justify the mechanical properties of the joint and mainly those of plasticity, being all of them influenced by the processing conditions. In this work the influence of the laser welding speed on the tensile behaviour of duplex stainless steel welded joints is presented. The microstructure of the obtained seams and of the heat affected zone will be evaluated by means of optic and scanning electron microscopy. Also, different microhardness profiles have been obtained to evaluate the modifications in the mechanical properties both in the seam and the zone of thermal affection.

Las uniones soldadas de aceros inoxidables siempre presentan problemas por las modificaciones microestructurales que suceden en la zona afectada por el calor. Particularmente, los aceros inoxidables dúplex presentan cambios microestructurales muy importantes al solidificar el cordón y formar estructuras, fundamentalmente ferríticas, con formación de austenita en borde de grano. Estas modificaciones microestructurales, junto a las que suceden en la ZAC, son las que justifican las propiedades mecánicas de la unión y fundamentalmente las de plasticidad. Y todo ello en función de las condiciones de procesado. En este trabajo se presenta la influencia de la velocidad de soldeo en las propiedades a tracción de uniones soldadas por láser de chapas de acero inoxidables dúplex. La microestructura de los cordones obtenidos y de la zona afectada por el calor se ha evaluado mediante microscopía óptica y electrónica de barrido, y se han obtenido diferentes perfiles de microdureza que

Efeito da transformação do ninho manual modelo holandês em mecânico na postura de ovos de cama em matrizes de frangos de corte Effect of the transformation of a hand-operated Dutch nest into a mechanical nest on the laying of floor eggs in broiler breeders

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Fernando Pilotto

2010-10-01

Full Text Available Este trabalho visou adaptar o ninho manual modelo Holandês, cujo formato é bem aceito por matrizes de frangos de corte, a um modelo que permita fazer a coleta mecânica dos ovos. A adaptação consistiu em substituir a forração de maravalha por uma lâmina de madeira estofada e colocar uma correia de transporte para fazer o recolhimento dos ovos. Esta adaptação foi avaliada em dois experimentos no mesmo galpão, das 25 às 35 semanas de idade. Em ambos os experimentos, foram disponibilizados 69 módulos, cada um com 24 ninhos (ninho manual, para a coleta dos ovos de 7.690 galinhas e um módulo adaptado com 24 ninhos (ninho mecânico para a coleta mecânica dos ovos de 110 galinhas. No primeiro experimento, foram comparadas as porcentagens semanais de ovos produzidos e de ovos de cama e, no segundo experimento, além dessas variáveis, foram observadas as porcentagens de ovos trincados e de ovos sujos de ninho. Também no experimento 2, visando reduzir os ovos postos na cama observados no experimento 1, foi colocada maravalha sobre a forração desenvolvida, do alojamento até 26ª semana. Utilizou-se um esquema fatorial 2 õ 11, no qual a parcela principal foi constituída pelos ninhos mecânico e manual e as subparcelas pelas 11 semanas de avaliação. A porcentagem semanal de ovos produzidos foi semelhante entre os dois tipos de ninho, tanto no experimento 1 como no experimento 2. As porcentagens de ovos cama (experimentos 1 e 2, ovos sujos e ovos trincados (experimento 2 obtidas com o ninho mecânico foram maiores que com o ninho manual. No experimento 2, a colocação de maravalha no ninho mecânico não contribuiu para a redução da porcentagem de ovos de cama. A transformação do ninho manual em mecânico aumentou o número de ovos postos na cama, de ovos trincados e de ovos sujos, comprovando pior aceitação desse tipo de ninho pelas galinhas.This experiment aimed at adapting the Dutch manual nest model, whose format is well

Lixiviación de calcopirita mecánicamente activada utilizando ácido sulfúrico

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Danny Guzmán

2010-01-01

Full Text Available Con el objetivo de estudiar el efecto de la activación mecánica sobre la lixiviación de CuFeS2, cuatro muestras de este mineral fueron sometidas a molienda durante 1, 5, 8, y 15 h en un molino Atritor. Los polvos obtenidos fueron caracterizados microestructuralmente y morfológicamente mediante difracción de Rayos-X (DRX y microscopía electrónica de barrido (MEB, respectivamente. Posteriormente fueron lixiviados en una solución de H2SO4(0,54 M a temperatura de 298 K. La concentración de Cu+2 en las soluciones fue determinada mediante espectrofotometría de absorción atómica. Los resultados obtenidos indicaron que el aumento del tiempo de molienda provoca un aumento en la recuperación de Cu, alcanzando un valor máximo de 38,2 % para una molienda de 15 h.

Activación mecánica del caolín como vía para la fabricación de azul ultramar

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Oscar Jaime Restrepo Baena

2004-01-01

Full Text Available La molienda del caolín en molinos de anillos causa una destrucción progresiva de la estructura cristalina original. Los estudios granulométricos demuestran que la molienda de los granos de caolín se produce por fuerzas de cizalladura, ocasionando un deslizamiento de los planos que conforman las partículas, distorsionándolas y aglomerándolas. El estudio de rayos X de mostró una pérdida casi completa de la estructura cristalina. Los análisis de DTA y TGA mostraron que la pérdida del agua de composición interna se produce desde el momento que comienza el calentamiento. Los estudios de microscopía electrónica de barrido muestran granos de forma y tamaño irregular que difieren notablemente de la muestra original. Con las muestras de caolín activado mecánicamente, se fabricó el pigmento Azul Ultramar utilizando un horno de tubo, los resultados obtenidos muestran un producto de características de calidad comparables a los conseguidos utilizando el caolín calcinado (10. Este estudio muestra que la activación mecánica del caolín, puede convertirse en una alternativa a la calcinación, proceso que actualmente se realiza a nivel industrial.

Eficacia ante el dolor y la discapacidad cervical de un programa de fisioterapia individual frente a uno colectivo en la cervicalgia mecánica aguda y subaguda

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Leonardo Gregorio Antúnez Sánchez

2017-08-01

Conclusiones: Los pacientes con cervicalgia mecánica en estado agudo o subagudo experimentan una mejora estadísticamente significativa del dolor y de la discapacidad cervical tras recibir ambas modalidades de tratamiento de fisioterapia empleadas en nuestro estudio, mostrándose la modalidad de tratamiento individual más eficaz que la colectiva.