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Biomedical subjects

M C Martín

Publications and source records attributed to M C Martín.

At least 19 recordsLinked to original sources

Multiplex PCR for the detection and identification of dairy bacteriophages in milk.

Bacteriophage infections of starter lactic acid bacteria are a serious risk in the dairy industry. Phage infection can lead to slow lactic acid production or even the total failure of fermentation. The associated economic losses can be substantial. Rapid and sensitive methods are therefore required to detect and identify phages at all stages of the manufacture of fermented dairy products. This study describes a simple and rapid multiplex PCR method that, in a single reaction, detects the presence of bacteriophages infecting Streptococcus thermophilus and Lactobacillus delbrueckii, plus three genetically distinct 'species' of Lactococcus lactis phages commonly found in dairy plants (P335, 936 and c2). Available bacteriophage genome sequences were examined and the conserved regions used to design five pairs of primers, one for each of the above bacteriophage species. These primers were designed to generate specific fragments of different size depending on the species. Since this method can detect the above phages in untreated milk and can be easily incorporated into dairy industry routines, it might be readily used to earmark contaminated milk for use in processes that do not involve susceptible starter organisms or for use in those that involve phage-deactivating conditions.

Animals↗

Real-time polymerase chain reaction for quantitative detection of histamine-producing bacteria: use in cheese production.

Biogenic amines are toxic substances that appear in foods and beverages as a result of AA decarboxylation. The enzyme histidine decarboxylase catalyzes the decarboxylation of histidine to histamine, the biogenic amine most frequently involved in food poisoning. The aim of the present work was to develop a real-time quantitative PCR assay for the direct detection and quantification of histamine-producing strains in milk and cheese. A set of primers was designed, based on the histidine decarboxylase gene sequence of different gram-positive bacteria. The results show the proposed procedure to be a rapid (total processing time < 2 h), specific and highly sensitive technique for detecting potential histamine-producing strains. Chromatographic methods (HPLC) verified the capacity of real-time quantitative PCR to correctly quantify histamine accumulation.

Animals↗

Multi-day radon signals with a radioactive decay limb -- occurrence and geophysical significance.

Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes.

Journal Article↗

Multicenter study of the multiple organ dysfunction syndrome in intensive care units: the usefulness of Sequential Organ Failure Assessment scores in decision making.

OBJECTIVE: This study examined the incidence and mortality of multiple organ dysfunction syndrome (MODS) in intensive care units, evaluated the limitation of life support in these patients, and determined whether daily measurement of the Sequential Organ Failure Assessment (SOFA) is useful for decision making. DESIGN AND SETTING: Prospective, observational study in 79 intensive care units. PATIENTS AND PARTICIPANTS: Of the 7,615 patients admitted during a 2-month period we found 1,340 patients to have MODS. MEASUREMENTS AND RESULTS: We recorded mortality and length of stay in the intensive care unit and the hospital and the maximum and minimum total SOFA scores during MODS. Limitation of life support in MODS patients was also evaluated. Stepwise logistic regression was used to determine the factors predicting mortality. The in-hospital mortality rate in patients with MODS was 44.6%, and some type of limitation of life support was applied in 70.6% of the patients who died. The predictive model maximizing specificity included the following variables: maximum SOFA score, minimum SOFA score, trend of the SOFA for 5 consecutive days, and age over 60 years. The model diagnostic yield was: specificity 100%, sensitivity 7.2%, positive predictive value 100%, and negative predictive value 57.3%; the area under the receiver operating characteristic curve was 0.807. CONCLUSIONS: This model showed that in our population with MODS those older than 60 years and with SOFA score higher than 9 for at least 5 days were unlikely to survive.

Decision Making↗

The functional genetic variation in the PTPN22 gene has a negligible effect on the susceptibility to develop inflammatory bowel disease.

The aim of this study was to assess the possible association between the protein tyrosine phosphatase non-receptor 22 (PTPN22) gene 1858C-->T (rs2476601, encoding R620W) polymorphism and inflammatory bowel disease (IBD). Our study population consisted of 1113 IBD [544 ulcerative colitis (UC) and 569 Crohn's disease (CD)] patients and 812 healthy subjects. All the individuals were of Spanish white origin. Genotyping of the PTPN22 gene 1858C-->T polymorphism was performed by real time polymerase chain reaction technology, using TaqMan 5'-allelic discrimination assay. The frequency of the PTPN22 1858T allele in healthy subjects was 6.2% compared with 6.7% in the UC patients and 5.1% in Crohn's patients. No statistically significant differences were observed when the PTPN22 1858C-->T allele and genotype distribution among CD patients, UC patients and healthy controls were compared. These results indicate that the PTPN22 1858C-->T polymorphism does not appear to play a major role in IBD predisposition in our population.

Alleles↗

Cytotoxin and pyrogenic toxin superantigen gene profiles of Staphylococcus aureus associated with subclinical mastitis in dairy cows and relationships with macrorestriction genomic profiles.

A set of 84 Staphylococcus aureus isolates collected from the milk of cows with subclinical mastitis in Asturias (a cattle region of Spain) and six control strains were tested for sequences of genes encoding hemolysins (hla, hlb, hld, hlg, and hlg-2), leukotoxins (lukPV, lukM, and lukED), toxic shock syndrome toxin (tst), and enterotoxins (sea to see, seg to ser, and seu) by conventional and multiplex PCR. It was found that 84, 83, 11, and 39 isolates carried some type of hl, luk, tst, or se gene, respectively, which were arranged in 14 exotoxin genotypes. All of the isolates were negative for lukPV, hlg, sea, sed, see, sej, sek, sep, seq, and ser. Two gene groupings could be related with pathogenicity islands-[lukED, seg, sei, sem, sen, seo +/- seu] with Sabeta-1 and [tst, sec, sel] with SaPIbov, present in 45 and 13.1% of the isolates, respectively-while 11.9% of them carried both islands. Only one contained seb (together with upsilonSabeta-1), and another contained seh (together with lukED). The isolates were also analyzed by pulsed-field gel electrophoresis performed with SmaI. Thirty-nine SmaI profiles (similarity coefficient [S] = 0.94 to 0.21) were differentiated; 12, 1, and 10 of these, respectively, were generated by isolates presumptively carrying Sabeta-1, SaPIbov, or both. Five SmaI profiles (S > or = 0.8) formed a cluster, which contained 20 and 10 isolates carrying one (upsilonSabeta-1) or both islands. These data show the high frequency of genes encoding cytotoxins and pyrogenic toxin superantigens, their relationship with pathogenicity islands, and their distribution among a diversity of genetic types of S. aureus related to subclinical mastitis.

Animals↗

Genetic procedures for identification of enterotoxigenic strains of Staphylococcus aureus from three food poisoning outbreaks.

Three food poisoning restaurant outbreaks due to Staphylococcus aureus, occurring during June-October 2002 in the Principality of Asturias (PA), Spain, provided the basis for investigating some aspects of the molecular epidemiology of this organism. The methods applied to identify strains and lineages included multiplex-polymerase chain reaction (PCR) to detect nine enterotoxin (se) genes, and three DNA fingerprinting procedures: pulsed-field gel electrophoresis (PFGE) with SmaI, randomly amplified polymorphic DNA (RAPD) with two selected primers, and plasmid restriction analysis with HindIII. Thirty-two isolates were differentiated into three non-se and 12 se strains, which were outbreak-specific, except for one that was represented in two of the outbreaks. In outbreak 1, the 16 food isolates analyzed had sec, seg and sei genes and generated a distinctive DNA fingerprint, being assigned to a single strain. This strain could be categorized as endemic in the PA and associated to manually handled dairy products and nasal carriers. In outbreak 2, the four food isolates analyzed fell into three strains, each one displaying a different se-gene profile (sea, sec and seg-seh-sei) and a distinctive DNA fingerprint. In outbreak 3, the five food isolates tested fell into four seg-sei strains generating identical RAPD but different PFGE and plasmid profiles, and one sea strain also collected from two nasal carriers. This last strain had also been found in manually handled vegetables in outbreak 2, and it belongs to a not very frequently found sea lineage in the PA. Multiplex-PCR to detect se genes together with the three applied DNA fingerprint typing procedures proved therefore to be useful tools in subclassifying S. aureus for epidemiological purposes.

DNA Fingerprinting↗

Septicaemia due to Corynebacterium striatum: molecular confirmation of entry via the skin.

Septicaemia due to Corynebacterium striatum occurs infrequently. A case of C. striatum septicaemia with a known skin focus is reported in a 69-year-old male with ischaemia, refractory anaemia and treated for thyroid cancer. The characterization and typing of blood and cutaneous isolates was carried out using biochemical and DNA molecular typing methods to analyse the isolates. This is the first reported case with a documented source.

Aged↗

Enterotoxin production and DNA fingerprinting in Staphylococcus aureus isolated from human and food samples. Relations between genetic types and enterotoxins.

A total of 224 Staphylococcus aureus strains from human carriers (110 strains) and manually handled foods (114 strains) collected in the Principality of Asturias, Spain over 1995-1999 were analysed for the production of enterotoxins (SEs) A, B, C, and D by a reversed passive latex agglutination test and by amplification of ent genes (A, B, C, D, E, and J) using PCR. Sixty-two strains were enterotoxigenic and a good relation between detection of SEs and their ent genes was found. No strain carried entE and all strains producing SED carried entD and entJ genes. Among the enterotoxigenic strains the percentages registered were 29, 8, 35, 18, 2, 2, and 6 for SEA, SEB, SEC, SEDJ, SEAC, SEADJ and SECDJ, respectively. DNA fingerprinting of 77 strains (the SE prototypes, 62 enterotoxigenic and 10 non-enterotoxigenic [NE]) was carried out by randomly amplified polymorphic DNA using two selected primers independently. Combining results from both primers, 10 genetic types were defined, which showed a different degree of relationship (similarity coefficient: 0.9-0.36) and were clustered into three lineages. One lineage clustered five genetic types and a wide diversity of strains, mainly SEA, SEB, SEDJ, and NE. Another lineage clustered only SEC, SECDJ and NE strains. These two lineages showed a low genetic relationship and appeared as endemic in healthy humans living in the Principality of Asturias. The third lineage included only the prototype strains for SEA and SEE.

Bacteriological Techniques↗

Salmonella serotype Virchow causing salmonellosis in a Spanish region. Characterization and survey of clones by DNA fingerprinting, phage typing and antimicrobial resistance.

The diversity of Salmonella serotype Virchow organisms causing human salmonellosis in a Spanish region over 1990-1996 was studied by genetic and phenotypic procedures. Isolates showing identical DNA fingerprintings (ribotypes, RAPD-, REP- and ERIC-types) were clustered into the same lineage. Eight lineages were defined, of which only one caused diseases throughout the studied period. Eleven phage types (PTs) were represented, the most frequent being PTs 8, 19, 31, throughout the study period, and PT4a only during 1994. Class I integrons with variable regions of 1000-, 1600-, and 2300-bp in size were respectively present in 24, 3 and 5 multiresistant isolates; 43.5% of isolates were susceptible to antimicrobials, the rest were grouped into 17 R-profiles, including from one up to eight resistances. Plasmids could be recovered from 71.5% of isolates and grouped into 25 plasmid profiles (with 1-7 plasmids each); a 3.6 kb cryptic-plasmid and a 60 kb virulence-plasmid were those most frequently found. Phage type, presence and size of integrons, and resistance profile were used to differentiate 39 clones. During the period studied 135 cases of Virchow salmonellosis were identified; 93 were apparently sporadic whereas the remainder were associated with four outbreaks. Infants under 1 year constituted the most frequent age group, with 30 gastroenteritis and two septicaemia episodes. In the four outbreaks, different clones falling into the prevalent lineage were implicated but each clone was involved in only one outbreak.

Adolescent↗

Generation of food-grade recombinant lactic acid bacterium strains by site-specific recombination.

The construction of a delivery and clearing system for the generation of food-grade recombinant lactic acid bacterium strains, based on the use of an integrase (Int) and a resolvo-invertase (beta-recombinase) and their respective target sites (attP-attB and six, respectively) is reported. The delivery system contains a heterologous replication origin and antibiotic resistance markers surrounded by two directly oriented six sites, a multiple cloning site where passenger DNA could be inserted (e.g., the cI gene of bacteriophage A2), the int gene, and the attP site of phage A2. The clearing system provides a plasmid-borne gene encoding beta-recombinase. The nonreplicative vector-borne delivery system was transformed into Lactobacillus casei ATCC 393 and, by site-specific recombination, integrated as a single copy in an orientation- and Int-dependent manner into the attB site present in the genome of the host strain. The transfer of the clearing system into this strain, with the subsequent expression of the beta-recombinase, led to site-specific DNA resolution of the non-food-grade DNA. These methods were validated by the construction of a stable food-grade L. casei ATCC 393-derived strain completely immune to phage A2 infection during milk fermentation.

Animals↗

Endarteritis and mycotic aortic aneurysm caused by an oral strain of Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans was isolated from blood cultures of a 33-year-old febrile patient with a previously undiagnosed coarctation of the aorta. Subgingival samples from diseased periodontal pockets revealed the presence of A. actinomycetemcomitans. An infected (mycotic) aortic aneurysm and endarteritis were diagnosed and surgically treated. The identity of blood and oral clinical isolates of A. actinomycetemcomitans was supported by genetic analysis, including fingerprinting by restriction fragment length polymorphism, ribotyping, and random amplified polymorphic DNA; biotyping; and antibiogram typing. These data strongly suggest that the periodontal pockets were the primary source of A. actinomycetemcomitans endarteritis in this case.

Actinobacillus Infections↗

Genetic typing methods applied to the differentiation of clonal lines among Salmonella enterica serogroup G strains causing human salmonellosis.

In Spain, in November 1995, an epidemiological alert recommended the surveillance of Salmonella serogroup G. The nine clinical isolates collected after and the four collected before the alert in Asturias were differentiated into six clonal lines by the combination of results from HincII ribotyping, PCR ribotyping, and RAPD typing using primers named A and S. The seven Gumpensis isolates showed identical DNA fingerprinting with the four typing procedures falling into a line. Six of these were collected during May-August from people living in a single health area suggesting that they could be associated with a community outbreak. The four Worthington isolates fell into three other lines, one Poona isolate into another line and one Havana isolate into another. 100% typeability was shown with all methods. The reproducibility of HincII ribotyping was better than that of PCR-based methods, although these were less time-consuming. The highest discriminatory power was obtained with HincII ribotyping and RAPD typing using primer A.

Adult↗

Usefulness of ribotyping in a molecular epidemiology study of shigellosis.

Ribotyping performed with six restriction endonucleases was used to study the molecular epidemiology of shigellosis in Asturias, Spain. The series included Shigella sonnei from 34 sporadic cases, 3 outbreaks and 3 reference strains, and S. Flexneri from sporadic cases and 1 reference strain. The S. sonnei strains were grouped into 5 ribotypes with Sal I, 4 with Hind III and Pvu II, 3 with Bgl II and EcoR I and 2 with Hinc II (Discriminatory Index (DI) between 0.54 and 0.14); the S. flexneri into 5 ribotypes with Sal I, Hinc II and Hind III, and 4 with the other enzymes (DI = 0.71 - 0.63). The combination of results for 2 or more enzymes facilitated and additional discrimination, the highest values in S. sonnei were for the 6 enzymes (16 types, DI = 0.91) and in S. flexneri for some combinations of 3 or more enzymes (7 types, DI = 0.81). Ribotypes with the 6 enzymes defined 16 clonal lines in S. sonnei and 7 in S. flexneri, which showed a different degree of genetic heterogeneity, and all the lines of each species falling into a different cluster. No line appeared as clearly endemic in the bowels of Asturian people.

Bacterial Typing Techniques↗

[Cytokines and nitric oxide in streptococcal toxic shock syndrome].

The plasma levels of endotoxin, tumor necrosis factor- alpha (TNF-alpha), interleukin -1 beta (IL-beta), IL-6, IL-8 and the nitrites and nitrates (NO2-/NO3-) as stable metabolites of nitric oxide (NO) were studied in the plasma of 2 patients with the streptococci toxic shock syndrome (STSS) associated to necrotizing fasciitis. A plasma profile of inflammatory mediators with high cytokine concentrations and NO2-/NO3- were observed with circulating endotoxin not being detected in plasma. The first patient died of fulminant refractory shock while the second survived following subacute evolution. The mediators profile, which was much higher in the first case, coincided with clinical severity. These data suggest that the cytokines and NO may have a role in the physiopathology of STSS and the severity of it is related to the levels of these mediators in the acute phase.

Adult↗