LA CONSULTA SEMANAL

MARZO 2001

CONSULTA

Am J Manag Care 2000 Dec;6(23 Suppl):S1197-201
Is drug resistance affecting treatment outcomes?
Bishai W
Antimicrobial drug resistance is a growing concern for the medical community.Although cases of drug resistance to Streptococcus pneumoniae are on the increase, there has been no change in mortality rates. The fact that the medical literature shows no proven correlation between drug-resistant S pneumoniae and clinical failure suggests that concerns about drug resistance in S pneumoniae may be overstated. Therefore, in treating community-acquired pneumonia, physicians should also weigh other important considerations such as pharmacology, safety, tolerability, and dosing convenience.

Publication Types:
  Review
  Review, tutorial


Am J Manag Care 2000 Dec;6(23 Suppl):S1178-88
Clinical choices of antibiotics: judging judicious use.
Steinberg I
Scientific literature widely documents the current overuse of antibiotics but often does not address the issue of the judicious use of antibiotics. Multiple analyses of prescribing patterns consistently reveal inappropriate prescribing of antibiotics, even when the clinician is aware of appropriate antibiotic use. In addition to overprescribing antibiotics, providers frequently address therapy failures by switching to same-class antibiotic agents. Additional investigations report that prescribing of antibiotics at the first office visit tends to increase, rather than decrease, costs and has marginal impact on patient outcomes. Patient education interventions, delivered prior to illness, can significantly reduce inappropriate use of antibiotics and reverse resistance trends. A variety of developments in antimicrobial use and resistance and newer antibiotic and respiratory infection management strategies are discussed.
Publication Types:
  Review
  Review, tutorial


Int J Antimicrob Agents 2001 Jan;17(1):21-6
Resistance to antimicrobial agents in Mediterranean countries.
Gur D, Unal S
Director of Hacettepe University, Children's Hospital, Clinical Microbiology Laboratory, 06100, Ankara, Turkey. dg01-k@tr-net.net.tr
Publication Types:
  Review
  Review, tutorial


Int J Antimicrob Agents 2001 Jan;17(1):9-19
Quality measures of antimicrobial drug use.
Gyssens IC
Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center Rotterdam, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands. gyssens@bacl.azr.nl
Antimicrobial use is the major determinant in the development of resistance. Many parameters of importance for optimal quality of antimicrobial therapy have already been defined. Maximal efficacy of the treatment should be combined with minimal toxicity at the lowest cost. Quality of antimicrobial drug use is dependent on knowledge of many aspects of infectious diseases. Considering efficacy, many of our indications for antimicrobial use need critical evaluation. Irrational use should be discouraged. Avoidance of the development of resistance is a quality parameter that will need increasing attention. This paper reviews the well-established factors that may influence the appropriateness of pharmacotherapy with antimicrobial drugs. It cites recent evidence supporting principles of prudent prescribing and gives an overview of audits that have addressed these parameters. Measures relating to resistance are discussed.
Publication Types:
  Review
  Review, academic


Int J Antimicrob Agents 2000 Nov;16(3):191-7
Development and persistence of multi-resistance to antibiotics in bacteria; an analysis and a new approach to this urgent problem.
van der Waaij D, Nord CE
University of Groningen, Groningen, The Netherlands. d.van.der.waaij@iaf.nl
The intestinal microflora may have more influence on infectious diseases, than the mere control of growth of opportunistic micro-organisms by colonisation resistance (CR) and unspecific stimulation of the immune system. In compromised patients the CR may become decreased for several reasons but mostly because antibiotics reach the intestine during treatment. The consequence of a CR-decrease is that antibiotic-resistant opportunistic micro-organisms may increase in numbers in the gut. In this context, it is hypothesised that if the CR could be maintained at a normal level, the risk for maintenance and spread of resistant strains could be mitigated. Such maintenance requires absence of active antibiotic substance in the gut. This might be brought by the inactivation of antimicrobial agents by intestinal contents. Intra-intestinal inactivation has been described to occur along two possible routes: (1) inactivation by chemical binding or absorption and (2) by enzymatic destruction. Secondly, the composition of the intestinal microflora should be maintained at a normal level in case of other reasons for CR-decrease than antibiotic activity. Comprehensive study of the composition of normal microflora and the strains of species which play a role in CR with techniques which have become available during last decade, is recommended as well as the application of certain pre- and probiotics. It is concluded that antibiotic inactivation may be an ancient strategy of nature which should become incorporated in antibiotic treatment. Antibiotic use and development of resistance may have occurred when ecosystems formed several billions of years ago. Protection against antibiotics produced by newcomers into the ecosystem may have developed as it was necessary to maintain locally available nutrients for the inhabitants of the ecosystem. Should this hypothesis be correct, it is plausible that antimicrobial inactivation by antibiotic inactivating molecules is ubiquitous. In the ecosystem of the digestive tract, molecules involved in inactivation may predominantly be formed by microorganisms.
Publication Types:
  Review
  Review, tutorial


Can J Microbiol 2000 Oct;46(10):867-77
A review of antimicrobial resistance in Canada.
Blondeau JM, Vaughan D
Department of Clinical Microbiology, St. Paul's Hospital (Grey Nuns'), Saskatoon, SK, Canada. blondeauj@sdh.sk.ca
Antimicrobial resistance is a global concern. Over the past 10 years, considerable efforts and resources have been expended to detect, monitor, and understand at the basic level the many different facets of emerging and increasing resistance. This review summarizes our current understanding of bacterial antimicrobial resistance issues in Canada with particular emphasis given to the Enterobacteriaceae, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus, Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Streptococcus pyogenes. In addition, future concerns and programs for ongoing surveillance are discussed.


Curr Opin Microbiol 2000 Oct;3(5):515-21
Pharmacodynamics in the study of drug resistance and establishing in vitro susceptibility breakpoints: ready for prime time.
Dudley MN, Ambrose PG
Microcide Pharmaceuticals Inc., 850 Maude Ave., Mountain View, CA 94043, USA. mdudley@microcide.com
Considerable advancements have been made in providing informative, relevant interpretations of the results of antimicrobial susceptibility tests to clinicians, clinical microbiologists, epidemiologists, and researchers. At the same time, the science of pharmacokinetics has flourished, and the importance of drug exposure in vivo on outcome is now recognized by researchers and clinicians alike. More recently, pharmacokinetic and quantitative measures of antimicrobial susceptibility have been integrated using pharmacokinetic-pharmacodynamic (PK-PD) models to forecast clinical and microbiological outcomes. Stochastic methods utilizing patient population pharmacokinetics, target organism minimum inhibitory concentration (MIC) distributions, and PK-PD targets from non-clinical models of infection or clinical data have established a new paradigm for determining in vitro susceptibility breakpoints and selection of empirical therapy in clinical practice. Given the increasing problem of antimicrobial resistance, these new tools are valuable additions for clinicians, researchers, and regulatory authorities.
Publication Types:
  Review
  Review, tutorial


Curr Opin Microbiol 2000 Oct;3(5):496-501
Antimicrobial use and bacterial resistance.
Monroe S, Polk R
Medical College of Virginia, Richmond, Virginia 23298, USA.
The current epidemic of bacterial resistance is attributed, in part, to the overuse of antibiotics. Recent studies have documented increases in resistance with over-use of particular antibiotics and improvements in susceptibility when antibiotic use is controlled. The most effective means of improving use of antibiotics is unknown. Comprehensive management programs directed by multi-disciplinary teams, computer-assisted decision-making, and antibiotic cycling have been beneficial in controlling antibiotic use, decreasing costs without impacting patient outcomes, and possibly decreasing resistance.
Publication Types:
  Review
  Review, tutorial


South Med J 2000 Sep;93(9):842-8 [Texto completo]
Confronting the problem of increasing antibiotic resistance.
Hellinger WC
Department of Internal Medicine, Mayo Clinic Jacksonville, Fla 32224, USA.
Significant increases in prevalence of resistance to antibiotics have been observed in common pathogens of humans in the United States and worldwide. The consequences of the appearance and spread of antibiotic resistance have included increasing morbidity, mortality, and cost of health care. The fundamental cause for the appearance and spread of antimicrobial resistance has been increasing antimicrobial use. However, other factors contribute in both inpatient and outpatient settings. Recognizing the important causes of increasing antibiotic resistance in these settings has led to practical recommendations, which health care facilities and outpatient practitioners will need to review, adapt, and apply for maximum local effectiveness for progress to be made in addressing one of the most challenging problems facing modern medicine.
Publication Types:
  Review
  Review, tutorial


Am J Manag Care 2000 May;6(8 Suppl):S409-18
Emerging resistance problems among respiratory tract pathogens.
Lister PD
The number-1 indication for antibiotic prescriptions in the United States is a respiratory tract infection. The changing spectrum of pathogens and emerging bacterial resistance are changing the way these infections are managed. The epidemiology of community-acquired pneumonia has changed significantly in the past 20 years, with increased diversity of pathogens and mortality. Emerging resistance in respiratory tract pathogens, particularly to beta-lactams, is an increasing concern. Of the important gram-negative pathogens, more than a third of Haemophilus influenzae isolates are now resistant to beta-lactam antibiotics, as well as virtually all isolates of Moraxella catarrhalis. Of the gram-positive organisms, more than 40% of Streptococcus pneumoniae isolates are no longer susceptible to penicillin, and methicillin resistance has been reported in up to half of Staphylococcus aureus isolates in some institutions. Among staphylococci, resistance to the beta-lactam methicillin is often accompanied by resistance to multiple classes of antibiotics, particularly the macrolides. Little resistance to fluoroquinolones has been reported among gram-negative respiratory tract pathogens and S pneumoniae, although increasing resistance may be seen as these drugs are used with increasing frequency. In contrast, fluoroquinolone resistance can develop rapidly in S aureus and appears to be associated with methicillin resistance. Fortunately, many of the newer fluoroquinolones appear to offer significant activity against methicillin-resistant S aureus isolates and are active against ciprofloxacin-resistant strains of S pneumoniae. Today, to combat respiratory tract infections, a broad-based empiric therapy needs to be used and bacterial resistance must be taken into account. New antimicrobial options must be considered, with an emphasis on effective drug use and optimal dosing. Even if a direct relationship between antibiotic resistance and clinical outcomes in the treatment of pneumonia in adults has not been extensively demonstrated, the increasing problem of resistance has changed treatment approaches for respiratory tract infections as a whole.
Publication Types:
  Review
  Review, tutorial


Rev Soc Bras Med Trop 2000 May-Jun;33(3):281-301
[Problems with gram-positive bacteria: resistance in staphylococci, enterococci, and pneumococci to antimicrobial drugs].
[Article in Portugese]
Tavares W
Faculdade de Medicina de Teresopolis, Escola de Ciencias Medicas de Volta Redonda, RJ, Brasil.
The resistance in staphylococci, enterococci, and pneumococci is reviewed. The author also recalls the first cases, and presents an overview of the distribution of cases in the world, the genetic and molecular mechanisms of resistance, the importance in Brazil and therapeutic alternatives. The factors that contribute to the dissemination of these problem bacteria and the measures for their control are emphasized.
Publication Types:
  Review
  Review, tutorial


Infection 1999;27 Suppl 2:S32-4
Antimicrobial resistance--pharmacological solutions.
Rubinstein E
Infectious Diseases Unit, Chaim Sheba Medical Center, Tel-Hashomer, Israel.
The interaction between microbial resistance and antibacterial agents occurs in a direct and an indirect fashion. Directly--through the development of resistance to the agent used, or to agents of the same class--as exemplified by the induction of beta-lactamase by both gram-positive and gram-negative bacteria. It also takes place through the development of resistance to compounds of different classes to the compound used, as exemplified by the loss of Streptococcus pneumoniae susceptibility to penicillin that is accompanied by a parallel loss of sensitivity to erythromycin and to tetracycline. As for the indirect way--microbial resistance may develop through selection of resistant organisms when the patient is treated with antibiotics, when the environment is contaminated with antibiotics (hospital) or when antibacterial agents are used in agriculture and animal husbandry.
Publication Types:
  Review
  Review, tutorial


Infection 1999;27 Suppl 2:S24-8
Combination therapy as a tool to prevent emergence of bacterial resistance.
Mouton JW
Dept. of Medical Microbiology, Canisius Wilhelmina Ziekenhuis Rotterdam, Nijmegen, The Netherlands.
Emergence of resistance is an ever increasing problem. One of the methods by which emergence of resistance may possibly be prevented, or at least delayed, is the use of combination therapy. Since the emergence of resistant mutants is a direct result of selective pressure by antimicrobial therapy, the chance of mutants resistant to two antimicrobials in the parent population being present is a product of mutation frequencies, provided that resistance mechanisms are independent. Comparative studies in in vitro pharmacokinetic models and in vivo indicate that emergence of resistance is less common when combination therapy is used. This is particularly true for microorganisms known to develop resistance relatively quickly, such as Pseudomonas aeruginosa, and resistance mechanisms which occur at a relatively high frequency.
Publication Types:
  Review
  Review, tutorial


Infection 1999;27 Suppl 2:S19-23
Drug resistance in intensive care units.
Albrich WC, Angstwurm M, Bader L, Gartner R
Medizinische Klinik, Klinikum Innenstadt der Ludwig-Maximilians-Universitat, Munchen.
Intensive care units (ICUs) are generally considered epicenters of antibiotic resistance and the principal sources of outbreaks of multi-resistant bacteria. The most important risk factors are obvious, such as excessive consumption of antibiotics exerting selective pressure on bacteria, the frequent use of invasive devices and relative density of a susceptible patient population with severe underlying diseases. Infections due to antibiotic-resistant bacteria have a major impact on morbidity and health-care costs. Increased mortality is not uniformly shown for all of these organisms: Methicillin-resistant Staphylococcus aureus (MRSA) seems to cause significantly higher mortality, in contrast to vancomycin-resistant enterococci (VRE). Therefore it is essential to diminish these potential risk factors, especially by providing locally adapted guidelines for the prudent use of antibiotic therapy. A quality control of antimicrobial therapy within a hospital, and especially within the ICU, might help to minimize the selection of multidrug-resistant bacteria. The restricted use of antimicrobial agents in prophylaxis and therapy has also been shown to have at least temporal effects on local resistance patterns. New approaches to the problem of drug resistance in ICUs are badly needed.
Publication Types:
  Review
  Review, tutorial


Infect Dis Clin North Am 2000 Jun;14(2):293-319
Pathogens resistant to antimicrobial agents. Epidemiology, molecular mechanisms, and clinical management.
Kaye KS, Fraimow HS, Abrutyn E
Department of Internal Medicine, Harvard Medical School, Boston, Massachusetts, USA.
The emergence of resistance to antimicrobial agents continues to be a major problem in the nosocomial setting and now in nursing homes and the community as well. Bacteria use a variety of strategies to avoid the inhibitory effects of antibiotic agents and have evolved highly efficient means for the dissemination of resistance traits. Control of antibiotic-resistant pathogens provides a major challenge for both the medical community and society in general. To control the emergence of resistant pathogens, CDC and infection control guidelines must be adhered to, and antibiotics must be used more judiciously.
Publication Types:
  Review
  Review, tutorial


Clin Infect Dis 2000 May;30(5):799-808
Antimicrobial susceptibility testing: special needs for fastidious organisms and difficult-to-detect resistance mechanisms.
Jorgensen JH, Ferraro MJ
Department of Pathology, The University of Texas Health Science Center, San Antonio 78284-7750, USA. jorgensen@uthscsa.edu
Clinical microbiology laboratories are faced with the challenge of accurately detecting emerging antibiotic resistance among a number of bacterial pathogens. In recent years, vancomycin resistance among enterococci has become prevalent, as has penicillin resistance and multidrug resistance in pneumococci. More recently, strains of methicillin-resistant Staphylococcus aureus with reduced susceptibility to vancomycin have been encountered. In addition, molecular techniques have demonstrated that there are still problems detecting methicillin resistance in staphylococci, especially in coagulase-negative species. Among members of the family Enterobacteriaceae, mutated beta-lactamase enzymes may confer difficult-to-detect resistance to later-generation penicillins and cephalosporins. Anaerobic bacteria are no longer entirely predictable in their susceptibility to agents that might be selected for empiric therapy. Therefore, clinical microbiology laboratories may not be able to rely on a single susceptibility testing method or system to detect all those emerging resistant or fastidious organisms. For reliable detection, laboratories may need to employ conventional, quantitative susceptibility testing methods or use specially developed, single concentration agar screening tests for some resistant species. Certain of these screening tests are highly specific, while others may require additional confirmatory testing for definitive results. Therefore, laboratories must retain the versatility to apply several different approaches to detect resistance in both common and infrequently encountered bacterial pathogens.
Publication Types:
  Review
  Review, tutorial


Infect Dis Clin North Am 2000 Mar;14(1):67-81, viii
Bacterial resistance to antimicrobial agents in Latin America. The giant is awakening.
Guzman-Blanco M, Casellas JM, Sader HS
Infectious Disease and Microbiology Unit, Hospital Vargas de Caracas, Venezuela.
Resistant bacteria are emerging in Latin America as a real threat to the favorable outcome of infections in community- and hospital-acquired infections. Despite present extensive surveillance, healthcare workers who most need the information may be unaware of this growing problem. Outbreaks of meningococci with diminished susceptibility to penicillin have been reported in the region; a constant increase of resistance to penicillin in pneumococci and poor activity of commonly used oral antibiotics for the treatment of community-acquired urinary tract infections have made the treatment of these infections more difficult. Reports from tertiary hospitals are similar to many other areas of the world, with increasing frequency of Klebsiella pneumoniae-carrying extended-spectrum beta-lactamase, multiresistant strains of Pseudomonas aeruginosa and Acinetobacter baumanni in ICU settings, and reports of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci. A surveillance network readily accessible to those who prescribe antibiotics in Latin America is highly desirable.
Publication Types:
  Review
  Review, tutorial


J Chemother 1999 Dec;11(6):518-23
Emerging antimicrobial resistance in the surgical compromised host.
Wilson AP
Department of Clinical Microbiology, University College Hospital, London, UK. p.wilson@academic.uclh.nthames.nhs.uk
Improvements in the treatment of compromised patients have resulted in their prolonged survival in a debilitated state. Patients have repeated courses of antibiotics and become colonised with multiresistant pathogens during a stay in the intensive care unit. Surgical wound infections can then be very difficult to treat. Methicillin-resistant Staphylococcus aureus is now common although wide variations in prevalence exist between countries and regions. Klebsiella spp with multiple resistance is a common cause of septicemia and can be associated with cephalosporin use. Acinetobacter spp and vancomycin-resistant enterococci can cause infections resistant to all readily available antibiotics. The prevalence of infection with each of these pathogens is increasing. Control measures should include hand washing, universal precautions for infection control, source isolation, restrictive antibiotic policy and antibiotic rotation. Although new agents currently in trials may be effective in the long term, the future for antibiotic treatment or prophylaxis of surgical infections is in doubt.
Publication Types:
  Review
  Review, tutorial


J Postgrad Med 1995 Apr-Jun;41(2):29-30
Antimicrobial resistance--a strident alarm.
Soman R
Publication Types:
  Review
  Review, tutorial


Mayo Clin Proc 2000 Feb;75(2):200-14
Clinical aspects of antimicrobial resistance.
Virk A, Steckelberg JM
Division of Infectious Diseases and Internal Medicine, Mayo Clinic Rochester, Rochester, Minnesota, USA.
Soon after penicillin was introduced into clinical use, an enzyme (penicillinase) that inactivated it was discovered. Since then, the variety of antimicrobial agents has increased substantially, along with a parallel increase in resistant pathogenic microorganisms. Resistance is now recognized against all available antimicrobial agents. Factors influencing the emergence of resistance include indiscriminate use of antibiotics, prolonged hospitalizations, increasing numbers of immunocompromised patients, and medical progress resulting in increased use of invasive procedures and devices. This article provides an update on clinical aspects of a few commonly found resistant microorganisms relevant to day-to-day clinical practice. A discussion of all resistant organisms is beyond the scope of this report. Both viral and mycobacterial resistance have been addressed in previous articles in this symposium.
Publication Types:
  Review
  Review, tutorial


Emerging Infectious Diseases 1999;Vol5 Nro3 [Texto completo]
Bacterial Resistance to Antimicrobial Agents: Selected Problems in France, 1996 to 1998 Helene Aubry-Damon* and Patrice Courvalin?
*Institut de Veille Sanitaire, Saint-Maurice, France; and ?Centre National de Référence des Antibiotiques, Institut Pasteur, Paris, France


Drugs 1999 Oct;58(4):589-607
Antibiotic usage in animals: impact on bacterial resistance and public health.
van den Bogaard AE, Stobberingh EE
Department of Medical Microbiology, University Maastricht, The Netherlands. A.vandenBogaard@CPV.Unimaas.NL
Antibiotic use whether for therapy or prevention of bacterial diseases, or as performance enhancers will result in antibiotic resistant micro-organisms, not only among pathogens but also among bacteria of the endogenous microflora of animals. The extent to which antibiotic use in animals will contribute to the antibiotic resistance in humans is still under much debate. In addition to the veterinary use of antibiotics, the use of these agents as antimicrobial growth promoters (AGP) greatly influences the prevalence of resistance in animal bacteria and a poses risk factor for the emergence of antibiotic resistance in human pathogens. Antibiotic resistant bacteria such as Escherichia coli, Salmonella spp., Campylobacter spp. and enterococci from animals can colonise or infect the human population via contact (occupational exposure) or via the food chain. Moreover, resistance genes can be transferred from bacteria of animals to human pathogens in the intestinal flora of humans. In humans, the control of resistance is based on hygienic measures: prevention of cross contamination and a decrease in the usage of antibiotics. In food animals housed closely together, hygienic measures, such as prevention of oral-faecal contact, are not feasible. Therefore, diminishing the need for antibiotics is the only possible way of controlling resistance in large groups of animals. This can be achieved by improvement of animal husbandry systems, feed composition and eradication of or vaccination against infectious diseases. Moreover, abolishing the use of antibiotics as feed additives for growth promotion in animals bred as a food source for humans would decrease the use of antibiotics in animals on a worldwide scale by nearly 50%. This would not only diminish the public health risk of dissemination of resistant bacteria or resistant genes from animals to humans, but would also be of major importance in maintaining the efficacy of antibiotics in veterinary medicine.
Publication Types:
  Review
  Review, academic


BMJ 1998 Sep 5;317(7159):657-60 [Texto completo]
The origins and molecular basis of antibiotic resistance.
Hawkey PM
Department of Microbiology, and Antimicrobial Research Centre, University of Leeds, Leeds LS2 9JT. P.M.Hawkey@Leeds.ac.uk
Publication Types:
  Review
  Review, tutorial


BMJ 1998 Sep 5;317(7159):652-4 [Texto completo]
The epidemiology of antimicrobial resistance in hospital acquired infections: problems and possible solutions.
Struelens MJ
Department of Clinical Microbiology, Hopital Erasme, Universite Libre de
Bruxelles, 808 route de Lennik, 1070 Brussels, Belgium. marc.struelens@ulb.ac.be
Publication Types:
  Review
  Review, tutorial


BMJ 1998 Sep 5;317(7159):651 [Texto completo]
Surveillance of antimicrobial resistance--an international perspective.
Williams RJ, Ryan MJ
Division of Emerging and other Communicable Diseases Surveillance and Control, World Health Organisation, CH-1211 Geneva, Switzerland.
Publication Types:
  Review
  Review, tutorial


BMJ 1998 Sep 5;317(7159):647-50 [Texto completo]
Antimicrobial resistance in developing countries.
Hart CA, Kariuki S
Department Medical Microbiology and Genitourinary Medicine, University of Liverpool, Liverpool L69 3GA. cahmm@liv.ac.uk
Publication Types:
  Review
  Review, tutorial


N Engl J Med 1996 Nov 7;335(19):1445-53
Antimicrobial-drug resistance.
Gold HS, Moellering RC
Division of Infectious Diseases, Deaconess Hospital and Harvard Medical School,
Boston, MA 02215, USA.
Publication Types:
  Review
  Review, tut