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Biomedical subjects

Rita Moure

Publications and source records attributed to Rita Moure.

8 recordsLinked to original sources
PubMed2005

Evaluation of different methods for detecting methicillin (oxacillin) resistance in Staphylococcus aureus.

OBJECTIVES: To evaluate the performance of oxacillin, cefazolin, cefoxitin, cefotaxime and imipenem discs; Etest for oxacillin; microdilution; agar screening plates with 2 and 6 mg/L of oxacillin; and PBP2' agglutination for detection of methicillin-resistant Staphylococcus aureus (MRSA). METHODS: A total of 102 clinical S. aureus isolates, including 51 MRSA isolates, tested by PCR for the presence or absence of the mecA gene (gold standard method), isolated from different patients and at different times, were tested with: oxacillin (1 microg), cefazolin, cefoxitin, cefotaxime and imipenem (all 30 microg) discs; Etest for oxacillin; microdilution with oxacillin; agar screening tests (ORSAB medium) with 2 mg/L or 6 mg/L of oxacillin; and PBP2' agglutination with two different kits for detection of MRSA strains. RESULTS: The cefoxitin disc, ORSAB medium and PBP2' detection all showed 100% sensitivity. The cefoxitin, cefazolin and imipenem discs, Etest for oxacillin, microdilution and agar screening method with 6 mg/L at 24 h showed the highest specificity (100%), although variable degrees of sensitivity. The cefoxitin disc, which showed negative and positive predictive values of 100% and 98%, respectively was the best method for detecting MRSA isolates. CONCLUSIONS: In the absence of availability of molecular biology techniques, the cefoxitin disc was the best predictor of methicillin resistance in S. aureus from among the techniques tested.

Bacterial Proteins↗
PubMed2005

Cloning and functional analysis of the gene encoding the 33- to 36-kilodalton outer membrane protein associated with carbapenem resistance in Acinetobacter baumannii.

We investigated a multiresistant strain of Acinetobacter baumannii isolated in our hospital. Analysis of the N-terminal peptide sequence of the outer membrane proteins (OMPs) purified from the strain allowed us to clone and sequence the nucleotides of the gene encoding the 33- to 36-kDa OMP associated with carbapenem resistance in A. baumannii.

Acinetobacter↗
PubMed2004

Lack of correlation between phenotypic techniques and PCR-based genotypic methods for identification of Enterococcus spp.

A total of 123 genetically-unrelated strains of Enterococcus spp. strains (51 Enterococcus faecalis, 57 Enterococcus faecium, 10 Enterococcus gallinarum, and 5 Enterococcus casseliflavus) were phenotypically identified by biochemical profiles and by using an automated method. The strains were also analyzed by a PCR assay to assess the accuracy of the phenotypically-based methods for identification of Enterococcus spp. With this aim, a PCR assay using different cell targets, which allows simultaneous detection of glycopeptide-resistant genotypes as well as identification to the species level by means of different gene targets, was used as the gold standard method. All 51 strains of E. faecalis were correctly identified, whereas 48 of 57 strains (84.2%) of E. faecium, were correctly identified. All of the strains of E. gallinarum and 3 out of 5 strains of E. casseliflavus were also correctly identified. The overall results showed that it is possible to identify Enterococcus spp. at the molecular level in less than 30 hours, compared with the 48-96 hours required for the phenotypically-based methods. The excellent accuracy of the PCR assay in identifying these species, particularly E. faecium, must also be emphasized. These findings may have implications for the routine clinical identification of enterococci species.

Bacterial Typing Techniques↗
PubMed2004

High-level resistance to ceftazidime conferred by a novel enzyme, CTX-M-32, derived from CTX-M-1 through a single Asp240-Gly substitution.

A clinical strain of Escherichia coli isolated from pleural liquid with high levels of resistance to cefotaxime, ceftazidime, and aztreonam harbors a novel CTX-M gene (bla(CTX-M-32)) whose amino acid sequence differs from that of CTX-M-1 by a single Asp240-Gly substitution. Moreover, by site-directed mutagenesis we demonstrated that this replacement is a key event in ceftazidime hydrolysis

Amino Acid Sequence↗
PubMed2003

[Antifungal susceptibility of Candida spp. isolates from blood cultures in a five-year period (1997-2001)].

INTRODUCTION: This retrospective study investigates the incidence of candidemia and antifungal susceptibility of Candida spp. isolates from blood cultures performed in the period from January 1997 to December 2001. METHODS: Amphotericin B, fluconazole, itraconazole and flucytosine minimal inhibitory concentrations (MICs) were determined using the Sensititre YeastOne broth microdilution assay for the 53 isolates detected in the study period: C. parapsilosis (22), C. albicans (19), C. glabrata (5), C. krusei (3), C. tropicalis (2) and C. guilliermondii (2). RESULTS: The incidence of candidemia was 0.25 episodes per 1000 admissions in the period studied. C. parapsilosis was present in 41.5% of cases, followed by C. albicans (35.8%), C. glabrata (9.4%), C. krusei (5.5%), C. tropicalis (3.7%) and C. guilliermondii (3.7%). Isolation of C. parapsilosis was significantly associated with the neonatal and pediatric ICU. None of the isolates presented an amphotericin B MIC > 1 micro g/ml. All the C. krusei isolates were resistant to fluconazole. Itraconazole resistance and dose-dependent fluconazole susceptibility was found in 80% of C. glabrata isolates. Only one C. parapsilosis isolate was resistant to flucytosine. CONCLUSIONS: The incidence of candidemia in our hospital was low. C. parapsilosis was the most common species and was associated with neonatal and pediatric ICUs. Fluconazole and itraconazole resistance was only found among C. krusei and C. glabrata isolates, which accounted for 15% of the total Candida spp. isolated from blood cultures in our hospital.

Adult↗
PubMed2002

Identification and broad dissemination of the CTX-M-14 beta-lactamase in different Escherichia coli strains in the northwest area of Spain.

During the course of a molecular epidemiology study of mechanisms of antibiotic resistance in the area served by our hospital (516,000 inhabitants), we isolated the gene encoding CTX-M-14 beta-lactamase. Thirty clinical strains (27 Escherichia coli and 3 Klebsiella pneumoniae isolates) with a phenotype of extended-spectrum beta-lactamase were collected from January to October 2001 and studied for the presence of the CTX-M-14 beta- lactamase gene. By isoelectric point determination, PCR, and nucleotide sequencing, we detected the presence of this gene in 17 E. coli strains belonging to 15 different genotypes (REP-PCR) causing infections in 17 different patients. Epidemiological studies based on medical records did not suggest any relationship between the patients infected with these E. coli strains and, interestingly, 7 of 30 patients harboring strains with extended-spectrum beta-lactamases never had contact with the hospital environment before the clinical E. coli isolation. Conjugation experiments revealed that this gene was plasmid mediated in the 17 E. coli strains, and plasmid restriction fragment length polymorphisms showed 9 different patterns in the 17 E. coli strains. By PCR, the sequence of the tnpA transposase gene of the insert sequence ISEcp-1 was detected in all the plasmids harboring the CTX-M-14 gene. These results strongly suggest that plasmid dissemination between different E. coli strains in addition to a mobile element (transposon) around the beta-lactamase gene may be involved in the spreading of the CTX-M-14 gene. This study reinforces the hypothesis that the epidemiology of the prevalence of the beta-lactamase genes is changing and should alert the medical community to the increase in the emergence of the CTX-M beta-lactamases worldwide.

Adolescent↗