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Biomedical subjects

M E Evans

Publications and source records attributed to M E Evans.

At least 37 records · Page 2Linked to original sources
PubMed1998

Levofloxacin selects fluoroquinolone-resistant methicillin-resistant Staphylococcus aureus less frequently than ciprofloxacin.

Seventeen methicillin-resistant Staphylococcus aureus (MRSA) with unique genotypes were examined to determine if resistance occurs more frequently with ciprofloxacin or levofloxacin. The mean single-step resistance rate to 4 x MIC of ciprofloxacin was 1.05 x 10(-5) (range <4.82 x 10[-11] to 5.06 x 10[-5]), and that to levofloxacin was 4.03 x 10(-6) (range <3.57 x 10[-13] to 4.10 x 10[-5]) (P < 0.05). When serially passaged, the mean MICs of ciprofloxacin and levofloxacin increased 3.0 +/- 1.5-fold and 1.8 +/- 1.4-fold, respectively (P < 0.05). Only four strains became resistant to levofloxacin, but eight became resistant to ciprofloxacin (P < 0.05). Ciprofloxacin selects resistant MRSA more frequently than levofloxacin.

Anti-Infective Agents↗
PubMed1998

Patterns of antibiotic-resistant Streptococcus pneumoniae in children in a day-care setting.

BACKGROUND: Streptococcus pneumoniae is one of the primary causes of illness and death among young children, and evidence suggests that the prevalence of antibiotic-resistant S pneumoniae is increasing. The purpose of this study was to investigate the prevalence of antibiotic-resistant S pneumoniae in a sample of children in day-care facilities in a region that includes both rural and urban communities. METHODS: Nasopharyngeal cultures were obtained from 104 children in eight day-care centers located in rural and urban central Kentucky in April and May, 1997. Thirty-five of the children produced isolates positive for S pneumoniae. Each isolate was tested for susceptibility to penicillin, trimethoprim-sulfamethoxazole, erythromycin, tetracycline, vancomycin, and cefotaxime. RESULTS: Of the children with S pneumoniae isolates, 54% had isolates that were resistant to penicillin and 40% that were resistant to trimethoprim-sulfamethoxazole. Twenty-one (60%) of the isolates had resistance to at least one of the six tested antimicrobials, with 15 (43%) having resistance to more than one of the antimicrobials. The mean age of children with isolates resistant to penicillin was significantly less (2.7 + 1.6) than those with penicillin-susceptible isolates (3.7 + 1.1, P = .02). There was no relation between resistance and rural or urban day-care location. CONCLUSIONS: A substantial proportion of S pneumoniae isolates in young children are resistant to antibiotics. Limiting the effect of S pneumoniae drug resistance may require a reexamination of outpatient treatment strategies for childhood respiratory tract infections.

Child↗
PubMed1997

Influenza control in acute care hospitals.

BACKGROUND: Influenza causes increased morbidity and mortality among patients in longterm care facilities, but little information is available on the impact of influenza in acute care settings. We wished to have such information when revising our hospital influenza control policy. METHODS: We reviewed recent reports of influenza among patients in acute care hospitals and surveyed large (approximately 500-bed) acute care teaching hospitals by telephone to determine the nature of their influenza control policies. RESULTS: Seventeen reports of influenza outbreaks in acute care hospitals were published from 1959 to 1994. Influenza A caused 13 of these outbreaks. Five involved children and 12 involved adults. The mean number of patients in each outbreak was 14 (range 1 to 49), with a mortality rate of 0% to 50% (median 0%, mean 6.5%). Health care workers were implicated in transmission in five reports. Vaccine was used infrequently during the outbreaks, and use of chemoprophylaxis was not reported. Our survey of current practices in 15 university-affiliated hospitals from 12 states revealed that all offered vaccine in the fall but none required either immunoprophylaxis or chemoprophylaxis at any time. Only three had formal policies detailing management of influenza in the hospital. CONCLUSIONS: Nosocomial influenza in acute care hospitals is infrequently reported and associated with a low mortality rate. Health care workers rarely comply with preventive measures, and few institutions have formal influenza control policies.

Acute Disease↗
PubMed1997

Molecular epidemiology of multiply antibiotic-resistant Shigella flexneri in Fortaleza, Brazil.

In northeastern Brazil, strains of Shigella flexneri resistant to multiple antibiotics are often found in patients in both urban areas and community hospitals. This study used pulsed-field gel electrophoresis (PFGE) and plasmid analysis to further analyze the molecular epidemiology of Shigella flexneri strains isolated from hospitals and an urban community in Fortaleza, Brazil. Twenty-six strains of S. flexneri from three distinct areas in the city of Fortaleza, Brazil, were examined: 14 strains from people with diarrhea who lived in an urban community of 2,000 persons, 5 strains from patients in the university hospital, and 7 strains from children in a pediatric hospital. PFGE identified six unique groups of S. flexneri circulating among patients during the 45-month study. Seven strains were further studied for antibiotic resistance plasmid profiles. Three unique antibiotic resistance plasmid profiles were found. Strains collected from the hospitalized patients demonstrated the variety of PFGE and antibiotic resistance patterns in the area. Strains collected from the patients living in the urban community setting demonstrated the persistence of certain PFGE patterns as well as the acquisition of multiple antibiotic resistance plasmids. Effective interventional strategies for such geographic locations as Fortaleza, Brazil, will be more complex than those for single-strain outbreak situations.

Brazil↗
PubMed1997

Amphotericin B lipid complex.

OBJECTIVE: To evaluate the published data on the effectiveness and safety of amphotericin B lipid complex (ABLC) for the treatment of invasive mycosis and to evaluate data describing the pharmacologic properties and pharmacokinetic behavior of ABLC in both animals and humans. DATA SOURCE: A MEDLINE search was conducted to identify literature published from 1965 to January 1997 for amphotericin B deoxycholate (DCAB) and ABLC. In addition, preliminary data published as abstracts and presented at national conferences on infectious disease and hematology within the last 6 years were also included in this review. STUDY SELECTION: Both human and animal studies were reviewed. Animal and in vitro studies were selected to evaluate the pharmacologic and toxicologic properties of ABLC. For the evaluation of the efficacy, safety, and pharmacokinetic behavior of ABLC, large, well-controlled studies were reviewed. In addition, data from open-label and emergency use protocols were also included in the review. DATA EXTRACTION: The study and analytical methods, results, and conclusions of the selected studies were evaluated. Pharmacokinetic data for both ABLC and DCAB that were derived from human subjects were also evaluated. DATA SYNTHESIS: DCAB has been the cornerstone for the treatment of invasive mycosis, even though it has a narrow therapeutic index. Infusion-related toxicities (e.g., fever, chills, rigors) are likely due to DCAB stimulation of cytokine and prostaglandin synthesis. Conversely, nephrotoxicity, the primary non-infusion-related toxicity, likely results from the nonselective cytotoxic interaction between DCAB and cholesterol-containing mammalian cells. ABLC represents a new approach to improving the therapeutic index of DCAB. Mammalian cytotoxicity is attenuated by complexing amphotericin B to a mixture of phospholipids. This alters the affinity of amphotericin B and decreases its selective transfer from the complex to cholesterol-containing mammalian cells. Fungi also possess lipase, which improves the selective transfer from the complex to ergosterol-containing cell membranes. In humans, the lipid formulation increases the volume of distribution of amphotericin B. Thus, compared with DCAB, larger doses of ABLC can be administered for a longer duration with less nephrotoxicity. However, the prevalence of infusion-related toxicities associated with ABLC is similar to that of DCAB. Whether the alteration in distribution improves efficacy by improving tissue concentrations of amphotericin B has not been determined. The cost of this agent will limit its use. CONCLUSIONS: ABLC has been shown to be at least as effective as DCAB, and it has been well tolerated in the clinical studies to date. Despite large dosages and extended courses of administration, there is little nephrotoxicity associated with its use. However, the cost of this agent will limit its use to the treatment of refractory mycosis or to cases where DCAB is contraindicated due to significant renal insufficiency.

Amphotericin B↗
PubMed1996

Child, family, and system outcomes of intensive case management in New York State.

New York State's Children and Youth Intensive Case Management (CYICM) was implemented in 1988 as one of several community-based initiatives for children with serious emotional disturbance (SED). Underlying this program is the goal of maintaining children with SED in the least restrictive environment appropriate to their needs. This paper presents CYICM child, family, and system outcomes over six years, describes program refinements, and explores continuing research efforts. Data are supportive of the positive outcomes associated with intensive case management for children with SED. Associated with enrollment in CYICM are a decrease in symptoms, improvement in functioning, and fewer hospitalizations in state-operated psychiatric centers, which translates into cost savings and a possible reduction in hospital beds.

Adolescent↗
PubMed1996

Vancomycin use in a university medical center: comparison with hospital infection control practices advisory committee guidelines.

OBJECTIVE: To compare actual vancomycin use in a hospital with the guidelines proposed by the Hospital Infection Control Practices Advisory Committee (HICPAC) of the Centers for Disease Control and Prevention. DESIGN: One-month prospective survey of all patients given vancomycin. Data were collected from patient and laboratory records and discussions with prescribing physicians. SETTING: Four hundred sixty-one-bed tertiary-care university hospital. RESULTS: Only 35% of the 101 vancomycin orders written during the audit were consistent with HICPAC guidelines. Twenty-eight patients were begun on vancomycin for the treatment of documented infections due to beta-lactam-resistant gram-positive bacteria or because preliminary culture results suggested such bacteria were present. Seven methicillin-resistant Staphylococcus aureus, two ampicillin-resistant enterococci, and 10 coagulase-negative staphylococci were recovered. Vancomycin use was judged inappropriate in 66 patients. The drug was used empirically without obtaining appropriate cultures (44 patients), as surgical prophylaxis (6 patients), for primary treatment of antibiotic-associated colitis (3 patients), for convenience in a hemodialysis patient (1 patient), or for other reasons not recommended by HICPAC (12 patients). CONCLUSIONS: Vancomycin use in our teaching center often was inconsistent with HICPAC guidelines. Information from the audit will be useful for designing strategies to improve vancomycin use.

Aminoglycosides↗
PubMed1995

Mordant factors that affect the fluorescence and counting of somatic cells by instruments.

The requirement for accuracy in the counting of somatic cells in milk has been increased by the use of this measurement as a basis of payment for milk. This paper reports on several factors that can substantially affect efficiency of staining and cell detection in various types of fluorescent cell counters. These mordant factors include sample age, chemical preservative, other sample preservation treatments and reagent properties. Experiments were conducted in several laboratories with Fossomatic 215 and 360 cell counting instruments to measure the effect of these mordant factors on both cell fluorescence and cell count. Counting efficiency was as low as 20% for some instruments counting some particular samples, depending upon the combination of adverse mordant factors. The problem of poor counting efficiency was also not detected by calibration samples that had more favourable mordant treatments applied. The adverse mordant factors were shown to reduce the intensity of fluorescence of cells for all instruments. We suggest that a significant reduction in counting efficiency due to these adverse mordant factors is most likely to occur when the particular instrument already has an intrinsic inability to separate cell fluorescence properly from background noise. This paper also discusses quality control samples, the impact of various factors on discriminator curves and the use of appropriate measures to maintain good calibration adjustment.

Animals↗
PubMed1995

Ehrlichiosis in Kentucky.

Ehrlichiosis is a recently described tick-borne disease characterized by headache, fever and chills, leukopenia, thrombocytopenia, and transaminase elevation. The presentation is similar to Rocky Mountain spotted fever but the rash is less frequently present in ehrlichiosis. The diagnosis is confirmed by elevated antibody titers to Ehrlichia chaffeensis or visualization of inclusions in white blood cells and the disease is easily cured with tetracyclines or chloramphenicol. Cases of ehrlichiosis are reported from southeastern, southcentral and midatlantic states. We report three cases of Ehrlichia infection acquired in Pulaski County and Fort Knox, KY during 1992-93.

Adult↗
PubMed1994

Assessing the outcomes of parent-and provider-designed systems of care for children with emotional and behavioral disorders.

There is a paucity of research on the outcomes associated with involving parents of children with emotional and behavioral problems as partners with professionals in designing and implementing a system of care. This study examines the systems, child, and family outcomes associated with providing flexible funds to two counties, one engaged in strengthening its provider-designed system and the other in developing and implementing a parent-designed system. This article describes the qualitative, network, and treatment outcome studies comprising the research.

Adolescent↗
PubMed1993

Effect of antibiotic class and concentration on the release of lipopolysaccharide from Escherichia coli.

The ability of six antibiotics from different classes to release radiolabeled lipopolysaccharide (LPS) from a phenotypically smooth galE mutant of Escherichia coli O111:B4 was examined. Antibiotic concentrations were 0.0625-512 micrograms/mL. LPS release increased as a function of the antibiotic concentration, reaching a limit at or near the concentration that killed the majority of bacteria. The maximum amount of LPS released by polymyxin B was 40.6% +/- 0.9%, by gentamicin 58.2% +/- 2.5%, by ciprofloxacin 65.8% +/- 2.5%, by ceftazidime 73.1% +/- 0.9%, by tetracycline 75.3% +/- 10.0%, and by imipenem 79.7% +/- 2.3%. In timed experiments, ceftazidime released 61.9% +/- 1.2%, imipenem 51.1% +/- 8.8%, and tetracycline 39.7% +/- 4.4% of the LPS within the first hour of incubation, whereas polymyxin B released 13.5% +/- 1.9%, gentamicin 9.8% +/- 3.6%, and ciprofloxacin 12.7% +/- 2.6% of the LPS (P < .05). Fluoro-radiography and immunoblot analyses revealed similar migration patterns for antibiotic-released and cell-bound LPS on SDS-PAGE gels, suggesting similar O-polysaccharide content in the two LPS fractions. The amount and rate of LPS release from an E. coli strain was dependent upon antibiotic class and concentration.

Anti-Bacterial Agents↗