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Marcus J Zervos

Publications and source records attributed to Marcus J Zervos.

18 recordsLinked to original sources
PubMed2006

Heterogeneity of vat(E)-carrying plasmids in Enterococcus faecium recovered from human and animal sources.

In this study, quinupristin/dalfopristin (Q/D)-resistant Enterococcus faecium isolates (33 from poultry farms and 1 from a human outpatient) with Q/D minimal inhibitory concentrations ranging from 4 microg/mL to 32 microg/mL were analysed. Polymerase chain reaction detected the presence of vat(E) in all isolates. Using pulsed-field gel electrophoresis (PFGE), 14 distinct PFGE patterns were identified. The human E. faecium isolate was distinguishable from the 33 farm isolates by PFGE. Southern hybridisation localised the vat(E) gene to an 11 kb plasmid and resulted in five plasmid hybridisation types. The vat(E)-carrying plasmid from the human isolate showed a nearly identical hybridisation pattern to a plasmid from a farm isolate. This study showed that the vat(E) gene, conferring resistance to Q/D, was carried on different plasmids in a heterogeneous group of E. faecium, some of which may be acquired by E. faecium capable of infecting humans.

Acetyltransferases↗
PubMed2006

Application of molecular techniques to the study of hospital infection.

Nosocomial infections are an important source of morbidity and mortality in hospital settings, afflicting an estimated 2 million patients in United States each year. This number represents up to 5% of hospitalized patients and results in an estimated 88,000 deaths and 4.5 billion dollars in excess health care costs. Increasingly, hospital-acquired infections with multidrug-resistant pathogens represent a major problem in patients. Understanding pathogen relatedness is essential for determining the epidemiology of nosocomial infections and aiding in the design of rational pathogen control methods. The role of pathogen typing is to determine whether epidemiologically related isolates are also genetically related. To determine molecular relatedness of isolates for epidemiologic investigation, new technologies based on DNA, or molecular analysis, are methods of choice. These DNA-based molecular methodologies include pulsed-field gel electrophoresis (PFGE), PCR-based typing methods, and multilocus sequence analysis. Establishing clonality of pathogens can aid in the identification of the source (environmental or personnel) of organisms, distinguish infectious from noninfectious strains, and distinguish relapse from reinfection. The integration of molecular typing with conventional hospital epidemiologic surveillance has been proven to be cost-effective due to the associated reduction in the number of nosocomial infections. Cost-effectiveness is maximized through the collaboration of the laboratory, through epidemiologic typing, and the infection control department during epidemiologic investigations.

Bacteria↗
PubMed2006

The application of molecular techniques to the study of hospital infection.

CONTEXT: Nosocomial infections represent an important cause of morbidity and mortality in hospital settings, resulting in high health care costs. The roles of an epidemic investigation are to recognize that a problem exists, to compare characteristics of affected persons with those of similar but unaffected persons (case-control study), and to identify risk factors. Integrating typing methods as part of conventional epidemiologic surveillance is cost-effective and results in a reduction in rates of nosocomial infections. During the past 10 years, there has been unprecedented progress in molecular biology and in the application of nucleic acid technology to the study of the epidemiology of human infections. OBJECTIVES: To summarize the available molecular tests for determination of the relatedness of microorganisms causing nosocomial infections, emphasizing the most useful applications of the tests to the study of the epidemiology of hospital-acquired infection; and to discuss the appropriate use of these tests in the prevention and control of hospital-associated infection. DATA SOURCE: Published English-language literature from 1980 to the present. CONCLUSIONS: Pulsed-field gel electrophoresis is the method of choice for strain delineation. The newest techniques include polymerase chain reaction and multilocus sequence typing, in which various housekeeping genes that are stable markers of strain identity are sequenced. Molecular techniques are broadly applicable to the study of diverse pathogens. Typing data obtained by DNA analysis should always be considered together with epidemiologic information, because only this combination will enable the most accurate epidemiologic evaluation.

Cost-Benefit Analysis↗
PubMed2004

Epidemiology of antimicrobial resistance in enterococci of animal origin.

OBJECTIVE: We evaluated the epidemiology of antimicrobial resistance in enterococci from animal farms and the potential relation of resistance to antimicrobial use. METHODS: Enterococci from faecal samples from 18 beef cattle, 18 dairy cattle, 18 swine, 13 chicken, and eight turkey farms were prospectively evaluated over a 6 year period from 1998 to 2003. RESULTS: We evaluated 1256 isolates of Enterococcus faecium and 656 isolates of Enterococcus faecalis. None was vancomycin resistant. Quinupristin/dalfopristin, gentamicin and ciprofloxacin resistance rates in E. faecium were 2%, 0% and 55% in beef cattle, 8%, 7% and 47% in dairy cattle, 21%, 1% and 47% in swine, 85%, 12% and 23% in chicken, and 52%, 13% and 24% in turkey isolates, respectively. For E. faecalis, gentamicin resistance rates were 0% in beef cattle, 24% in dairy cattle, 37% in swine, 32% in chicken, and 29% in turkey isolates, whereas 12%, 9%, 21%, 64% and none of isolates from beef, dairy, swine, chicken, and turkey farms, respectively, were resistant to ciprofloxacin. Quinupristin/dalfopristin resistance in E. faecium was more common on chicken and turkey farms using virginiamycin (P<0.0001 for both) compared with farms not using a streptogramin, gentamicin resistance was more common on dairy farms using gentamicin (P<0.0001) compared with farms not using this antibiotic, and ciprofloxacin resistance was more common on turkey and dairy farms using enrofloxacin compared with those with no enrofloxacin use (P=0.02 and P=0.04, respectively). For E. faecalis, gentamicin resistance was more frequently detected on dairy and swine farms using gentamicin (P<0.0001 and P=0.0052, respectively) and ciprofloxacin resistance was more common on beef farms using enrofloxacin (P<0.0001) compared with farms not using these antimicrobials. PFGE showed multiple strain types with some clones common between animals of the same animal species. CONCLUSIONS: This study shows the presence of a significant reservoir of antibiotic-resistant enterococci among farm animals. Resistance was more common on farms using antimicrobial agents.

Agriculture↗
PubMed2004

Molecular and clinical epidemiology of vancomycin-resistant Enterococcus faecalis.

OBJECTIVES: With the recent emergence of vancomycin-resistant (VR) Staphylococcus aureus, subsequent to the suggested transfer of the vanA resistance gene from Enterococcus faecalis, we sought to determine risk factors for acquisition of VR E. faecalis and to evaluate the molecular epidemiology of this less-prevalent and less-studied species of VR enterococcus. METHODS: We compared clinical isolates of VR E. faecalis from 71 patients, collected over 12 years in a large community teaching hospital, with isolates from 126 patients with vancomycin-susceptible E. faecalis. RESULTS: Risk factors for VR E. faecalis acquisition by multivariate analysis were nursing home residence (P = 0.0005), haemodialysis (P = 0.009), decubitus ulcers (P = 0.03) and receipt of parenteral vancomycin (P = 0.0002). Twenty-one percent of VR E. faecalis demonstrated vanA and 79% vanB resistance. The number of VanA isolates increased over time. Molecular analysis showed vanA or vanB in multiple PFGE groups. CONCLUSIONS: The results of this study suggest gene dissemination among some isolates and intra-hospital spread of other isolates. The risk factors identified clearly suggest that VR E. faecalis is a nosocomial pathogen and should be considered in infection control practices. Further surveillance of VR E. faecalis is warranted, due to the potential spread of vancomycin resistance among enterococci and staphylococci.

Confidence Intervals↗
PubMed2004

Pertinacious habit on a rehabilitation unit: repetitive finger licking while paging through the clinical chart.

A survey was performed to determine the frequency of unrecognized repetitive licking of fingers while reviewing hospital charts by various healthcare professionals who, by this habit, may be putting themselves at risk of acquiring a nosocomial infection. Nine of 14 charts demonstrated the presence of Staphylococci aureus, cultures obtained from three of nine charts grew methicillin-resistant S. aureus, and six grew methicillin-susceptible S. aureus. Of the 50 healthcare professionals surveyed, five (10%) admitted to habitual repetitive licking of fingers while reviewing charts. In addition, 30 (60%) of those surveyed had observed other professionals doing so. Forty-seven (94%) acknowledged that they did not routinely wash their hands after reviewing the charts, potentially placing themselves at risk of acquiring a nosocomial infection. As an immediate consequence of this study, staff members have been encouraged to wash their hands before and after reviewing a patient's chart.

Allied Health Personnel↗
PubMed2004

Telithromycin.

Telithromycin (Ketek), Aventis Pharma), a ketolide, belongs to a new class of antibiotics that was developed for the treatment of upper and lower respiratory tract infections. The prevalence of penicillin and macrolide resistance among respiratory pathogens is increasing in the USA. Telithromycin is highly active against beta-lactam, macrolide and fluoroquinolone reduced-susceptibility pathogens. Its efficacy has been shown to be equal or superior to comparator agents in numerous studies. It has a broad in vitro spectrum versus usual respiratory pathogens and oral once-daily dosing that increases patient compliance. Telithromycin penetrates rapidly into neutrophils in bronchopulmonary tissue, with peak levels obtained in 1 to 2 h. Results of clinical trials show clinical-esponse rates similar to comparator agents. The most frequent adverse events involve the gastrointestinal system, with mild to moderate diarrhea and nausea. A low rate of discontinuation was observed in the studies. Telithromycin is an effective first-line treatment for mild to moderate respiratory infections in adults.

Anti-Bacterial Agents↗
PubMed2003

Quinupristin-dalfopristin resistance in gram-positive bacteria: mechanism of resistance and epidemiology.

Antimicrobial resistance in gram-positive bacteria is a continuing problem resulting in significant morbidity, mortality, and cost. Because of this resistance, new antimicrobial agents have been needed. Quinupristin-dalfopristin is a recently approved agent for treatment of these infections. Shortly after its introduction into clinical medicine, resistance was reported. Resistance can occur by one or more of several mechanisms, including enzymatic modification, active transport of efflux mediated by an adenosine triphosphate-binding protein, and alteration of the target site. Resistance is rare in isolates of staphylococci and Enterococcus faecium from humans. Resistance is common in isolates recovered from food animals and is related to the use of virginiamicin as a feed additive. Considering the effect antimicrobial resistance has on human health, as well as its economic impact, measures to preserve the usefulness of these agents and delay the development of resistance are urgently needed.

Anti-Bacterial Agents↗
PubMed2003

Relationship between fluoroquinolone use and changes in susceptibility to fluoroquinolones of selected pathogens in 10 United States teaching hospitals, 1991-2000.

We retrospectively examined the relationship between fluoroquinolone use and the susceptibilities of 11 bacterial pathogens to fluoroquinolones in 10 US teaching hospitals from 1991 through 2000. Statistical significance was determined by 2-way analysis of variance, with the number of isolates tested each year as a weighting factor. The analysis of baseline-to-end point change in the percentage of susceptibility and the slope of the regression line (trend line) for logit percentage of susceptibility showed that the overall percentage of susceptibility to fluoroquinolones decreased significantly during the study period (P<.05) and that change in percentage of susceptibility was significantly related to change in fluoroquinolone use (P<.05). Particularly notable were the decreases in the susceptibilities of Pseudomonas aeruginosa, Proteus mirabilis, and Escherichia coli (decreases of 25.1%, 11.9%, and 6.8%, respectively).

Anti-Infective Agents↗
PubMed2003

Structures, locations, and transfer frequencies of genetic elements conferring high-level gentamicin resistance in Enterococcus faecalis isolates in Greece.

The elements conferring high-level gentamicin resistance in 64 clinical isolates of Enterococcus faecalis were characterized by PCR and by restriction enzyme hybridization analysis of genomic and plasmid DNA. There was a strong association between gentamicin resistance and the aac(6')-aph(2") gene carried on IS256-based elements with different structures, locations, and transfer characteristics.

Acetyltransferases↗
PubMed2003

Plasmid content of a vancomycin-resistant Enterococcus faecalis isolate from a patient also colonized by Staphylococcus aureus with a VanA phenotype.

Vancomycin-resistant Enterococcus faecalis coisolated with vancomycin-resistant (VanA) Staphylococcus aureus was found to contain two plasmids, designated pAM830 (45 kb) and pAM831 (95 kb). pAM830, found to be conjugative and closely related to the Inc18 family of broad-host-range conjugative plasmids, encodes resistances to vancomycin (via a Tn1546-like element) and erythromycin; pAM831 encodes resistances to gentamicin, streptomycin, and erythromycin.

Bacterial Proteins↗
PubMed2003

Comparison of microscan broth microdilution, synergy quad plate agar dilution, and disk diffusion screening methods for detection of high-level aminoglycoside resistance in enterococcus species.

We compared the dried MicroScan microdilution panel, Synergy Quad plate agar dilution, and high-potency disk diffusion screening methods for the detection of high-level aminoglycoside resistance in 815 enterococcal bloodstream isolates. Agreement between the three methods was 99% when testing for high-level gentamicin resistance and 96% when testing for high-level streptomycin resistance.

Anti-Bacterial Agents↗
PubMed2002

Association between the presence of enterococcal virulence factors gelatinase, hemolysin, and enterococcal surface protein and mortality among patients with bacteremia due to Enterococcus faecalis.

The potential virulence factors of enterococci include production of enterococcal surface protein (Esp), gelatinase, and hemolysin. Gelatinase- and hemolysin-producing strains of Enterococcus faecalis have been shown to be virulent in animal models of enterococcal infections. Esp production has been shown to enhance the persistence of E. faecalis in the urinary bladder. We determined the presence of the esp gene and production of gelatinase and hemolysin in 219 E. faecalis isolates from a larger prospective study of 398 patients with enterococcal bacteremia. Thirty-two percent of isolates carried the esp gene, 64% produced gelatinase, and 11% produced hemolysin. There was no significant association between 14-day mortality and any of the markers studied, singly or in combination.

Adolescent↗
PubMed2002

Thrombocytopenia associated with linezolid therapy.

We evaluated the incidence and clinical characteristics of linezolid-induced thrombocytopenia in 19 patients who were treated with linezolid. Overall, thrombocytopenia (platelet count, <100,000 platelets/mm(3)) was observed in 32% of patients who received linezolid for >10 days; gastrointestinal bleeding was observed in 1 patient and 4 patients required platelet transfusions. These data suggest that even patients who are not considered to be at risk for development of thrombocytopenia should be monitored closely if linezolid therapy is continued for >10 days.

Acetamides↗
PubMed2002

In vitro susceptibility of vancomycin-resistant enterococci (VRE) to fosfomycin.

We evaluated the in vitro activity of fosfomycin against 75 clinical isolates of vancomycin-resistant enterococci (VRE). Using the NCCLS breakpoint for susceptibility of urinary tract isolates to fosfomycin (MIC > or = 256), 51 out of 52 Enterococcus faecium and all Enterococcus faecalis isolates tested were susceptible or intermediate to fosfomycin.

Anti-Bacterial Agents↗
PubMed2002

Molecular analysis of vancomycin-resistant Enterococcus faecalis from Michigan hospitals during a 10 year period.

We evaluated the molecular relatedness of 47 clinical isolates of vancomycin-resistant Enterococcus faecalis collected from 15 Michigan hospitals from 1991 to 2000. There were 17 PFGE strain types for the 47 isolates. Ten of 15 hospitals demonstrated interhospital, and three of 15 intrahospital, dissemination of some isolates. Forty-two isolates (89.4%) demonstrated vanB resistance. All vanA isolates comprised unique PFGE groups, suggesting transposon dissemination or the presence of a similar plasmid. The results of this study suggest inter- and intrahospital dissemination of strains of vancomycin-resistant E. faecalis during a 10 year period in Michigan.

Anti-Bacterial Agents↗