Biomedical subjects

A T A Box

Publications and source records attributed to A T A Box.

5 recordsLinked to original sources

PubMed2004

Methicillin-resistant staphylococci isolated from animals.

Staphylococci isolated from animals (n=311) were screened for methicillin resistance by oxacillin agar screening. Oxacillin-resistant strains were tested for the presence of the mecA gene by PCR. Isolates were identified by standard techniques and 16S rDNA analysis, and their antimicrobial susceptibilities were tested using an agar diffusion method. MecA-positive strains were further analyzed using pulsed-field gel electrophoresis (PFGE). From 11 multidrug-resistant staphylococci, 6 were mecA-positive: 2 methicillin-resistant Staphylococcus aureus (MRSA) and 4 Staphylococcus haemolyticus. Screening of 300 staphylococci (100 S. aureus, 100 S. intermedius and 100 coagulase-negative staphylococci (CNS)) randomly chosen from the strain collection of the Veterinary Microbiological Diagnostic Center yielded five oxacillin-resistant coagulase-negative staphylococci, four of which were mecA-positive. PFGE showed that all mecA-positive staphylococci isolated from animals had distinct patterns. However, one MRSA isolated from a flank fistula of a dog showed homology to a human epidemic MRSA cluster, suggesting that transfer of MRSA between humans and dogs might occur.

Animal Diseases↗

PubMed2004

False-positive results and contamination in nucleic acid amplification assays: suggestions for a prevent and destroy strategy.

Contamination of samples with DNA is still a major problem in microbiology laboratories, despite the wide acceptance of PCR and other amplification techniques for the detection of frequently low amounts of target DNA. This review focuses on the implications of contamination in the diagnosis and research of infectious diseases, possible sources of contaminants, strategies for prevention and destruction, and quality control. Contamination of samples in diagnostic PCR can have far-reaching consequences for patients, as illustrated by several examples in this review. Furthermore, it appears that the (sometimes very unexpected) sources of contaminants are diverse (including water, reagents, disposables, sample carry over, and amplicon), and contaminants can also be introduced by unrelated activities in neighboring laboratories. Therefore, lack of communication between researchers using the same laboratory space can be considered a risk factor. Only a very limited number of multicenter quality control studies have been published so far, but these showed false-positive rates of 9-57%. The overall conclusion is that although nucleic acid amplification assays are basically useful both in research and in the clinic, their accuracy depends on awareness of risk factors and the proper use of procedures for the prevention of nucleic acid contamination. The discussion of prevention and destruction strategies included in this review may serve as a guide to help improve laboratory practices and reduce the number of false-positive amplification results.

Clinical Laboratory Techniques↗

PubMed2004

Evaluation of genetic determinants involved in beta-lactam- and multiresistance in a surgical ICU.

Antibiotic resistance is a major and well-known problem in intensive care units (ICUs) world-wide and previously susceptible isolates become resistant through the acquisition of resistance determinants from other bacteria or the development of mutations, as is the case in beta-lactam resistance. We evaluated the presence of resistance determinants involved in beta-lactam resistance and multi-resistance in order to establish the contribution of horizontal gene transfer to the spread of resistance in a surgical ICU during an antibiotic rotation study. Pseudomonas aeruginosa and Enterobacteriaceae isolates were selected and iso-electric focusing (IEF), DNA-typing methods such as specific beta-lactamase and specific integron PCRs were performed to determine the presence of beta-lactamases. The PCRs specific for IMP-1, OXA-1, and VIM-type beta-lactamases performed on the selected P. aeruginosa and Enterobacteriaceae isolates with MICs for cephalosporins >1 mg/l did not demonstrate any of these beta-lactamases. IEF for 14 pseudomonads, representing 7 genotypes from 9 patients, showed a beta-lactamase with a pI larger than 8.5 in 13 of the isolates. The integrase PCR was positive for only five isolates from three patients and conserved segment PCR showed integrons of variable sizes (700, 900, 1,400 and 1,500 bp). Each patient had its own integron types. It can be concluded that integrons and associated resistance determinants played only a minor role in the surgical ICU and beta-lactam resistance among P. aeruginosa isolates was most likely due to the derepression of its AmpC gene.

Anti-Bacterial Agents↗

PubMed2003

[Methicillin resistant Staphylococcus aureus (MRSA) infection in a dog in the Netherlands].

In the Netherlands, methicillin resistant Staphylococcus aureus (MRSA) are regularly isolated from humans. We present the first isolation of MRSA from animal origin in the Netherlands. A coagulase positive staphylococcus was cultured from an infected wound in a Dutch dog that recently underwent surgery abroad. The staphylococcus was resistant to methicillin, ampicillin, amoxycillin + clavulanic acid, cephalexin, erythromycin, lincomycin, tetracycline, gentamicin and enrofloxacin. It was identified as S. aureus by fermentation of mannitol and Martineau-PCR. The presence of mecA was confirmed by PCR.

Animals↗

PubMed2002

Presence of integron-associated resistance in the community is widespread and contributes to multidrug resistance in the hospital.

Integrons are strongly associated with the multidrug resistance seen in gram-negative bacilli in the hospital environment. No data, however, are available on their prevalence in the community. This study is the first to show that integrons are widespread in Enterobacteriaceae in the community and that integron-associated resistance genes in the community constitute a substantial reservoir for multidrug resistance in the hospital.

Anti-Bacterial Agents↗