A young mother asks for a coil.
Explore the source record for details and available documents.
Adolescent↗
Biomedical subjects
L Free
Publications and source records attributed to L Free.
Rapid characterization schemes for surveillance isolates of vancomycin-resistant enterococci.
Surveillance cultures for vancomycin-resistant enterococci (VRE) and subsequent characterization of the isolates can be extremely burdensome and difficult. Therefore, efficient and reliable schemes for the characterization of surveillance isolates are needed. In this study, a commercial agar (bile esculin azide agar with 6 microg of vancomycin per ml [BEAA]; Remel, Lenexa, Kans.) was used in the initial screening step to establish relatively rapid (i.e., in < or = 24 h from the time of isolation) phenotype-based and PCR-based schemes for the detection and characterization of VRE. The phenotype-based scheme included Gram staining of growth on BEAA and subculture of cocci on sheep blood agar plates for vancomycin disk diffusion and pyrazinamidase (PYR) testing. For the PCR scheme, inocula for van gene detection were taken directly from the BEAA plates. The phenotypic approach was applied to 378 surveillance cultures that yielded growth on BEAA. Gram staining quickly eliminated gram-positive bacilli from further testing, and a negative PYR test classified 25 additional isolates as probable pediococci. A positive PYR test reliably identified 121 single-patient VRE isolates that included 83 Enterococcus faecium, 33 E. gallinarum, and 5 E. casseliflavus strains. The vancomycin inhibition zone size clearly distinguished VanA and VanB strains from VanC strains within 24 h of BEAA isolation. All VanA and VanB strains failed to produce zones of >6 mm, while only one VanC strain produced a zone of < 15 mm. Challenging this phenotypic scheme with 47 stock VRE isolates produced similar findings. In direct PCR analyses, false-negative vanA and vanB results occurred with 12% of the specimens. Many of the false-negative reactions also failed to produce an internal control product, which underscores the need for including control primers when a PCR scheme is used. In summary, the phenotype- and the PCR-based schemes provide efficient methods for characterizing VRE within 24 h of isolation.
Anti-Bacterial Agents↗
Factors influencing the vitek gram-positive susceptibility system's detection of vanB-encoded vancomycin resistance among enterococci.
Studies were conducted to identify factors contributing to the inability of the Vitek Gram-Positive Susceptibility system (GPS; bioMerieux, Vitek, Inc., Hazelwood, Mo.) to reliably detect vanB-mediated vancomycin resistance among enterococci. To some extent the accuracy of the GPS depended on a particular strain's level of resistance, as all isolates for which vancomycin MICs were > or = 128 mu g/ml were readily detected but detection of resistance expressed by several strains for which MICs were < or = 64 mu g/ml was sporadic. Factors besides the level of resistance were studied in two vanB strains. For one strain (Enterococcus faecium U8304), the ability of GPS to detect resistance was accurate and consistent, while for the other (Enterococcus faecalis V583), GPS results were inconsistent and unreliable. Using these isolates, we established that growth medium had the most notable effect on the detection of resistance. In the absence of vancomycin, Vitek GPS broth supported growth comparable to that obtained with brain heart infusion broth for both E. faecium U8304 and E. faecalis V583. However, in the presence of vancomycin the growth patterns changed dramatically so that neither VanB strain grew well in Vitek broth, and growth of V583 was barely detectable after 8 h of incubation. In contrast, good growth of both strains was observed in brain heart infusion broth supplemented with vancomycin. Additionally, the same medium effect was observed with other inducibly resistant VanB strains. In conclusion, although Vitek broth can support good enterococcal growth, this medium does not sufficiently support expression of vancomycin resistance by certain strains to allow them to be detected by the Vitek automated system. Furthermore, this observation establishes that the type of growth medium used can substantially influence the expression of vancomycin resistance and indicates that medium-based strategies should be explored for the enhancement of resistance detection among commercial systems.
Anti-Bacterial Agents↗
Inducible and constitutive expression of vanC-1-encoded resistance to vancomycin in Enterococcus gallinarum.
Clinical isolates Enterococcus gallinarum AIB39 and E. gallinarum GS1 were studied to establish whether the expression of vanC-1-mediated resistance may be inducible or constitutive. By growth curve analysis, strain AIB39 exhibited the same lag period (i.e., 1 to 1.5 h) whether it was subcultured to unsupplemented brain heart infusion broth or broth containing 6 micrograms of vancomycin per ml, a growth pattern typical of constitutively expressed resistance. Use of high-performance liquid chromatography (HPLC) to separate peptidoglycan precursor extracts substantiated this finding because the serine-terminating pentapeptide precursor UDP-MurNAc-L-Ala-D-Glu-L-Lys-D-Ala-D-Ser was produced in the presence and absence of vancomycin, whereas no UDP-MurNAc-L-Ala-D-Glu-L-Lys-D-Ala-D-Ala was detected. In contrast, results with strain GS1 were consistent with inducible expression. GS1 demonstrated a lag time that was 3 to 4 h longer when it was subcultured to vancomycin-containing broth than when it was subcultured in unsupplemented broth. HPLC analysis showed that in the absence of vancomycin only UDP-MurNAc-L-Ala-D-Glu-L-Lys-D-Ala-D-Ala was detected, but in the presence of drug only UDP-MurNAc-L-Ala-D-Glu-L-Lys-D-Ala-D-Ala was found. Inducible expression of vanC-1-mediated resistance in E. gallinarum is consistent with recent findings suggesting the presence of at least two ligases in this species. Although vanC-1 may be intrinsic to E. gallinarum, our findings raise doubt regarding the natural mechanism of this gene's expression.
Amino Acid Sequence↗
Investigation of the reformulated Remel Synergy Quad plate for detection of high-level aminoglycoside and vancomycin resistance among enterococci.
We investigated the accuracy of the recently released Remel Synergy Quad plate, a commercially available agar screening method for detecting high-level aminoglycoside and vancomycin resistance among enterococci that is based on the National Committee for Clinical Laboratory Standards recommended guidelines (National Committee for Clinical Laboratory Standards, M7-A3, 1993). The Synergy Quad correctly determined the gentamicin and streptomycin resistance status for > or = 97% of 147 Enterococcus faecalis and Enterococcus faecium isolates tested. Detection of vancomycin resistance also was reliable, as no false susceptibility occurred with 36 vancomycin-resistant E. faecalis and E. faecium strains and false resistance occurred only once with the 47 susceptible strains tested. One strain each of Enterococcus gallinarum and Enterococcus casseliflavus failed to grow on the screen, but because the true nature and significance of resistance in such isolates is unknown the implication of their screen negativity is uncertain. In summary, the Remel Synergy Quad provides a highly accurate and convenient method for susceptibility testing of enterococci against gentamicin, streptomycin, and vancomycin.
Aminoglycosides↗
A health professions faculty workload plan for a liberal arts setting.
This case study describes an approach to planning the workload and expenditure of allied health faculty effort. The plan is based upon a review of the literature, a survey of other schools in similar settings, and faculty negotiation. It meets the need for faculty accountability, congruence between faculty workloads and institutional goals, faculty staffing determinations, and a means to compare nursing and allied health faculty workloads with those of more traditional liberal arts faculty. The plan may serve as a model for other health professions academic units.
Faculty↗
A comparative study of dialysis techniques.
Comparative studies were performed on 19 patients who were dialysed initially for a mean of 25 h a week and then for a mean of 11.1 h a week over two 3-year periods. Clinical, biochemical, haematological and neurological valuations were performed, which showed no significant difference. As an adjunct to haemodialysis a perfusion system was added to 12 of these patients already stable on haemodialysis and estimations made of removal of middle molecular weight substances from plasma by a gel filtration method through a Sephadex column. The results of these various techniques are reported and the comparisons between haemodialysis, haemodialysis and ultrafiltration and haemodialysis, perfusion and ultrafiltration are given.
Blood↗