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Biomedical subjects

M E Evans

Publications and source records attributed to M E Evans.

At least 19 recordsLinked to original sources
PubMed2002

Selection of oxacillin resistance in oxacillin-sensitive Staphylococcus aureus through exposure to ciprofloxacin but not piperacillin/tazobactam.

Ten oxacillin-sensitive Staphylococcus aureus strains were grown on agar containing four times their ciprofloxacin MIC to determine if exposure to ciprofloxacin would increase their resistance to oxacillin. All strains grew on the ciprofloxacin-containing agar and subsequently grew on oxacillin-salt agar. The geometric mean MICs for oxacillin increased one- to sixteen-fold and remained elevated after ten passages on antibiotic-free agar. The mecA gene was not detected in any strain. There was no increase in oxacillin MICs when the bacteria were passaged on agar containing four times their MIC of piperacillin/tazobactam. Exposure of oxacillin-sensitive strains of Staphylococcus aureus to ciprofloxacin may increase their MICs to oxacillin.

Anti-Infective Agents↗
PubMed2001

Determining the frequency of resistance of Streptococcus pneumoniae to ciprofloxacin, levofloxacin, trovafloxacin, grepafloxacin, and gemifloxacin.

Newer fluoroquinolones have good activity against Streptococcus pneunoniae and may be useful clinically for the treatment of pneumonia. Although resistance among Streptococcus pneumoniae has been reported, it is rare. The frequency of single-step resistance and the emergence of resistance were compared in serial transfer of 49 clinical isolates of penicillin-sensitive and -resistant Streptococcus pneumoniae to ciprofloxacin, levofloxacin, trovafloxacin, grepafloxacin, and gemifloxacin. Single-step resistance frequencies to four times the minimum inhibitory concentration were 2.73 x 10(-6) (+/- 8.46 x 10(-6)) for ciprofloxacin, 1.78 x 10(-7) (+/- 4.62 x 10(-7)) for trovafloxacin, 5.45 x 10(-7) (+/- 1.24 x 10(-6)) for grepafloxacin, 6.78 x 10(-7) (+/- 1.38 x 10(-6)) for gemifloxacin, and 9.23 x 10(-8) (+/- 4.47 x 10(-7)) for levofloxacin. In serial transfer experiments, all isolates became resistant to clinically relevant levels of all fluoroquinolones after eight passages. The resistance occurred most rapidly with ciprofloxacin followed by grepafloxacin, gemifloxacin, trovafloxacin, and levofloxacin. These results show that strains with decreased susceptibility to fluoroquinolones occur frequently in cultures of Streptococcus pneumoniae, and this organism can readily become resistant to clinically relevant concentrations of fluoroquinolones in vitro.

Anti-Infective Agents↗
PubMed2001

Outcomes associated with clinical profiles of children in psychiatric crisis enrolled in intensive, in-home interventions.

Little is known about the characteristics of children and youth presenting at emergency settings in psychiatric crisis, and virtually nothing is known about their outcomes. The purpose of this study is to describe the clinical profiles of 238 children presenting at two psychiatric emergency settings and enrolled in a randomized controlled trial of three intensive in-home interventions. A second purpose is to examine child mental health outcomes, based on clinical profile and to suggest the utility of using a clinical-profiles approach.

Adolescent↗
PubMed2001

Conducting research in culturally diverse inner-city neighborhoods: some lessons learned.

Social, behavioral, and health research among disenfranchised groups in inner cities poses problems in collecting data. It is a challenge to achieve data of sufficient quantity and quality necessary to be scientifically usable. This article describes the experiences of a research team during two phases of data collection in a mental health intervention study in New York's South Bronx. Challenges in addressing human subject concerns, the formation of a fieldwork team, enrollment and retention of respondents, and administration of instruments are described and solutions are discussed. Emphasis is placed on researchers' approaches to the selection, orientation, and safety of interviewers, interviewer-respondent race and ethnic matching, contacts and rapport with respondents, and the handling of such interpersonal issues as distrust, poor cooperation, and family dynamics. The procedures developed took into consideration the culture and life conditions of the population to ensure a satisfactory response rate and high-quality data.

Cultural Diversity↗
PubMed2001

Levofloxacin failure in a patient with pneumococcal pneumonia.

OBJECTIVE: To report a case of levofloxacin failure in a patient with a penicillin-sensitive Streptococcus pneumoniae pneumonia. CASE SUMMARY: A previously healthy, immunocompetent, 53-year-old white man presented with penicillin-sensitive S. pneumoniae pneumonia. The patient was empirically placed on levofloxacin monotherapy, which was continued due to a local penicillin shortage. When the patient failed to improve, further susceptibility testing was ordered. The organism was found to have a penicillin minimum inhibitory concentration (MIC) of 0.023 microgram/mL and a levofloxacin MIC of 6 micrograms/mL. Effective antimicrobial therapy was delayed, as clinicians did not anticipate fluoroquinolone resistance. DISCUSSION: Newer fluoroquinolones such as levofloxacin have good activity against most S. pneumoniae isolates and are used for the treatment of pneumonia. Although resistance to these agents is rare, it has been reported. Current guidelines from the National Committee for Clinical Laboratory Standards do not recommend initial fluoroquinolone susceptibility testing. CONCLUSIONS: As fluoroquinolone resistance may not be identified by susceptibility patterns to other antibiotics, early fluoroquinolone susceptibility testing and increased awareness of resistance may aid clinicians in their treatment of pneumococcal disease.

Anti-Infective Agents↗
PubMed2000

Clinical infection control in gene therapy: a multidisciplinary conference.

Gene therapy is being studied for the treatment of a variety of acquired and inherited disorders. Retroviruses, adenoviruses, poxviruses, adeno-associated viruses, herpesviruses, and others are being engineered to transfer genes into humans. Treatment protocols using recombinant viruses are being introduced into clinical settings. Infection control professionals will be involved in reviewing the safety of these agents in their clinics and hospitals. To date, only a limited number of articles have been written on infection control in gene therapy, and no widely available recommendations exist from federal or private organizations to guide infection control professionals. The goals of the conference were to provide a forum where gene therapy experts could share their perspectives and experience with infection control in gene therapy and to provide an opportunity for newcomers to the field to learn about issues specific to infection control in gene therapy. Recommendations for infection control in gene therapy were proposed.

Congresses as Topic↗
PubMed2000

An evaluation of statewide strategies to reduce antibiotic overuse.

BACKGROUND: The rapid increase of antibiotic resistance poses a significant threat to human health. Overuse of antibiotics has been linked to rates of antibiotic resistance. This study assessed the utility of two common interventions--1) practice profiling and feedback and 2) patient education materials--implemented to decrease antibiotic prescribing for pediatric upper respiratory infections (URIs). METHODS: Based on Medicaid regions in Kentucky, primary care physicians managing pediatric respiratory infections in Medicaid were randomized into four groups. Groups received either 1) performance feedback only, 2) patient education materials only, 3) both feedback and education materials, or 4) no intervention. Participating physicians had their antibiotic prescribing assessed for the period of July 1, 1996, to November 30, 1997, with an intervention in June 1997. The study included 216 physicians and 124,092 episodes of care. RESULTS: All groups increased in proportion of episodes with antibiotics between the pre-intervention and post-intervention periods. Prescribing in the patient education group and the patient education and feedback group increased at a significantly lower rate than in the control group. Physicians did not change their coding of illness to justify antibiotics after the intervention, and there was no significant generalization of effect of the pediatric intervention on prescribing for adult URIs. CONCLUSIONS: These interventions demonstrate little if any impact on promoting appropriate antibiotic prescribing. Antibiotic prescribing for viral respiratory infections continues to increase, suggesting concomitant increases in antibiotic resistance.

Adult↗
PubMed2000

Genetic diversity and reproductive biology in Warea carteri (Brassicaceae), a narrowly endemic Florida scrub annual.

Carter's mustard (Warea carteri) is an endangered, fire-stimulated annual endemic of the Lake Wales Ridge, Florida, USA. This species is characterized by seed banks and large fluctuations in plant numbers, with increases occurring in postdisturbance habitat. We investigated the mating system, patterns of isozyme variation, and effective population sizes of W. carteri to better understand its population biology and to comment on reserve designs and management proposals relevant to this species. Warea carteri is self-compatible and autogamous, and probably largely selfing. Measures of genetic variation in W. carteri were lower than values reported for species with similar ecological and life history traits (6.6% of loci polymorphic within populations, 1.87 alleles per polymorphic locus, and 0.026 and 0.018 expected and observed heterozygosity, respectively). The high average value for Nei's genetic identity (0.989) reflects the paucity of genetic diversity. Genetic variation within populations was not correlated with aboveground population size, effective population size estimates (N(e)), or recent disturbance history. Much of the diversity detected was found among populations (F(ST) = 0.304). A significant cline in allele frequencies at one locus and a significant negative correlation between geographic distance and Nei's genetic identity also point to spatial organization of genetic diversity. As a result we propose that reserve design should include the entire geographic range of W. carteri. We also recommend that the natural fire regime be mimicked.

Journal Article↗
PubMed1999

Vancomycin use in a university medical center: effect of a vancomycin continuation form.

OBJECTIVE: To examine the impact of a new policy to ensure appropriate use of vancomycin in a 461-bed tertiary-care hospital. DESIGN: We instituted a policy that allowed physicians to prescribe vancomycin but that required them to complete a vancomycin continuation form and document that use conformed to Hospital Infection Control Practices Advisory Committee (HICPAC) guidelines if they wished to continue the drug beyond 72 hours. Vancomycin was stopped automatically at 72 hours if use was not consistent with guidelines, if an infectious diseases consultant did not approve the drug, or if the form was not completed. A pharmacist and infectious diseases specialist monitored use of vancomycin prospectively and interacted with prescribers when indicated. Educational efforts were limited to printing the HICPAC guidelines on the form and providing information about the policy in a newsletter. Patterns of prescribing and the economic impact of the form were evaluated over a 6-month period. RESULTS: Only 29% to 48% of vancomycin orders initially met HICPAC guidelines, but 77% to 96% of use was appropriate after 72 hours when the form was used. Inappropriate surgical prophylaxis, empirical therapy of intensive-care unit and transplant patients, and therapy for inadequately documented coagulase-negative staphylococcal infections remained problems. Vancomycin use fell from a mean of 136 (+/-52) g/1,000 patient days in the 12 months before the form to 78 (+/-22) g/1,000 patient days in the 9 months after institution of the form (P<.05). Net vancomycin acquisition costs and costs of ordering vancomycin serum levels fell by $357 and $19 per 1,000 patient days, respectively (P<.05). This represented annualized saving of approximately $47,000 in drug and monitoring costs. No adverse patient outcomes were seen as a result of the program. CONCLUSIONS: A vancomycin continuation form can decrease inappropriate vancomycin use and may save money. Additional educational efforts may be required to increase compliance with HICPAC guidelines during initial prescribing.

Academic Medical Centers↗
PubMed1999

Infection control in gene therapy.

Gene therapy is now being studied for the treatment of a wide variety of acquired and inherited diseases. Viruses used as vectors for gene transfer include retroviruses, adenoviruses, vaccinia viruses, adeno-associated viruses, and herpesviruses. These vectors, developed in the laboratory and in animal studies, are now being introduced into the clinical arena Infection control practitioners will be involved invariably in reviewing the use of these agents in their clinics and hospitals. This review summarizes key aspects of the more common vectors and makes recommendations for infection control.

Cross Infection↗
PubMed1999

Tuberculosis management practices in Kentucky: comparison with national guidelines.

BACKGROUND: We assessed the quality of tuberculosis management practices in a predominantly rural state. METHODS: Medical records of persons reported to the Centers for Disease Control and Prevention (CDC) with the diagnosis of tuberculosis were audited; management practices were compared with guidelines from the American Thoracic Society (ATS) and CDC. RESULTS: We reviewed 207 records from 24 health districts in Kentucky. These records represented 30% of the cases reported to the CDC during the 17-month study. Tuberculosis was diagnosed by culture in 66% of patients; 12 different antibiotic regimens for antibiotic sensitive bacteria were prescribed; human immunodeficiency virus testing was documented in only 39%; monitoring for drug toxicity and bacteriologic cure was appropriate in < 65%; directly observed therapy was used in only 38%, and only 23% of close contacts were reevaluated at 12 weeks. CONCLUSIONS: Tuberculosis management practices in Kentucky fall short of ATS/CDC guidelines. Continuing quality-improvement efforts are warranted.

Aged↗
PubMed1999

Polymyxin B sulfate and colistin: old antibiotics for emerging multiresistant gram-negative bacteria.

BACKGROUND: Polymyxin B sulfate and colistin, also known as colistimethate, have not been used for many years because less toxic antimicrobials are available. Gram-negative bacteria that are resistant to the aminoglycosides, beta-lactams, and fluoroquinolones are becoming more common. These bacteria are often susceptible to the polymyxins. OBJECTIVE: To present a review of the chemistry, antibacterial spectrum, dosing, pharmacokinetics, toxicity, and indications for polymyxin B sulfate and colistin. DATA SOURCE: A MEDLINE search (1966-1998) of the English-language literature was performed to identify primary literature on the polymyxins. Older citations ( 1949-1965) were identified through the bibliographies of these articles. STUDY SELECTION: All available reports of in vitro antibacterial activity, animal and clinical trials, and case reports were reviewed. DATA SYNTHESIS: The polymyxins are amphipathic molecules that interact with lipopolysaccharide in the bacterial outer membrane. They have potent antiendotoxic properties and antibacterial activity against Pseudomonas aeruginosa and many of the Enterobacteriaceae. Polymyxin B and colistin are usually given at a dose of 1.5-2.5 and 5 mg/kg/d, respectively, in two divided doses. Dosing must be altered in renal failure since the kidney is the primary route of elimination. Distribution into pleural fluid, joints, and cerebrospinal fluid is poor. Toxic effects involve the kidney and central nervous system. The polymyxins are recommended for serious systemic infections caused by gram-negative bacteria that are resistant to other agents. CONCLUSIONS: Polymyxin B sulfate and colistin have a role in the therapy of multidrug-resistant gram-negative bacterial infections.

Anti-Bacterial Agents↗
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↗