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At least 19 recordsLinked to original sources
PubMed2001

Microbial drug resistance and the roles of the new antibiotics.

Physicians should be cautious in prescribing broad-spectrum antibiotics, particularly vancomycin and the fluoroquinolones, because widespread use of these drugs is promoting antibiotic resistance. Resistance is now found in many organisms, including staphylococci, enterococci, streptococci, pneumococci, and Pseudomonas aeruginosa. Some resistant strains can be treated with alternative narrower-spectrum antibiotics. In addition, five newly licensed antibiotics are available, but they should be used judiciously because of their side effects, high cost, and ability to promote additional resistance.

Acetamides↗
PubMed1994

[Microbial drug resistance and the presence of plasmids in Salmonella strains isolated from different sources].

BACKGROUND: To establish the relationship between the presence of plasmid and their antimicrobial resistance of Salmonella strains. METHODS: We tested 171 strains of Salmonella isolated from different sources: natural waters (73 strains), food (23 strains), and from clinical samples (75 strains). The disk diffusion method was used to test the antimicrobial susceptibility of the strains to 13 drugs. Plasmid analysis were performed by agarose gel electrophoresis technique. RESULTS: Antimicrobial resistances of the strains significantly varies according to their primary isolation sources. Strains isolated from the water environment exhibited a full susceptibility to cephalothin and colistin, whilst all the strains isolated from food were sensitive to ampicillin, gentamicin, kanamycin, neomycin, tobramycin and trimethoprim-sulphamethoxazole. On the other hand, resistances to colistin, gentamicin and trimethoprim-sulphamethoxazole were not found in clinical isolates. From the 171 Salmonella strains tested, only 12.2% were sensitive to all the antimicrobials. The most frequently antibiotic resistances detected were to streptomycin (49.3%), tetracycline (33.1%) and nalidixic acid (30.7%). The percentage of strains that harboured plasmids was different depending on the source of isolation, ranging from 41.4% for water isolated, 76% for clinical isolates and 86.9% for food isolates. The relationship between antimicrobial resistance and plasmid presence is very close, since higher percentages of resistance to chloramphenicol, carbenicillin, cephalothin, kanamycin, neomycin, nalidixic acid and trimethoprim-sulphamethoxazole were obtained in strains containing plasmids. CONCLUSIONS: (a) The most frequently resistance detected in strains of Salmonella was to streptomycin (49.3% of the strains). On the other hand, only 0.6% of the strains were resistant to gentamicin. (b) Percentages of resistance to some antibiotics was higher in strains harbouring plasmids, that implies a relationship between the plasmid presence and the antibiotic resistance in Salmonella. (c) Curing of extrachromosomic elements by acridine orange showed a percentage of resistance lost greater than 70% for cephalothin, kanamycin, neomycin, and nalidixic acid. This indicates that the resistance to those antibiotics is mainly linked to plasmids. In the case of the unusual nalidixic acid-resistance, previously described in Shigella strains, suggests that are needed more studies to demonstrate the direct association between antimicrobial resistance and presence of plasmids.

Anti-Bacterial Agents↗
PubMedDate not supplied

Microbial resistance to drugs--a universal problem in urgent need of a comprehensive approach.

The last two decades have seen an increase in bacterial resistance to commonly used antibiotics all over the world. In the past five years the emergence of vancomycin-resistant Enterococcus and multidrug-resistant Streptococcus pneumoniae was particularly notable. Several factors have contributed to this, including inappropriate use of readily available antibiotics, survival of high-risk patients in critical care units, burn wards and cancer centres following treatment with multiple antibiotic combinations, increasing poverty and worsening of living conditions. The data available from South-east Asia, albeit limited, indicate that prevalence of antibiotic resistance in bacteria isolated from human and animal sources is higher than that reported from western countries. To combat this global problem, a multi-pronged approach is needed. Accurate antibiotic susceptibility data will be required to define the extent of the problem. Medical experts and scientific organizations will have to develop guidelines for the use of antibiotics in ambulatory, inpatient and animal husbandary areas. Cooperation between the medical community, regulating agencies and pharmaceutical industry will be needed to define policies governing the sale of antibiotics, drug promotional materials, physician education programmes and consumer education regarding the hazards of inappropriate antibiotic use. For long term control of infectious diseases, it is imperative that existing vaccines be appropriately utilized and new vaccines developed.

Anti-Bacterial Agents↗
PubMed1997

Microbial resistance to drug therapy: a review.

Microbial resistance to the antimicrobials in standard use is becoming more prevalent. A historical perspective frames further discussion. Bacterial resistance is most common, but resistance has been identified in fungi, viruses, and parasites. Resistance is a complex phenomenon that involves the microorganism, the environment, and the patient-separately and interactively. Resistance may be a characteristic of the microbe before exposure to a given drug or may arise as a consequence of therapy. Mechanisms of resistance to antibiotics are discussed. Antibiotic resistance is considered in both hospital and community settings, as ecosystems that are separate yet blending, and the major organisms demonstrating significant resistance problems are presented. A review of existing guidelines, strategies, and plans for addressing resistance and some recommendations conclude this review.

Anti-Bacterial Agents↗
PubMed1997

Rational approach to limiting emergence of antimicrobial drug resistance.

Microbial resistance to the available antimicrobial agents continues to be a major problem with regard to nosocomial and community acquired pathogens. The development of resistance to commonly used antimicrobials is of particular concern when it occurs in pathogenic organisms that cause invasive disease. This has implications on morbidity and mortality of infectious diseases, and will also result in escalated costs of care due to the use of alternative antimicrobials which are often more costly. The increasing frequency of drug resistance has been attributed to combinations of microbial characteristics, selective pressure of antimicrobial use and societal factors that enhance the transmission of drug resistant organisms. The emergence of antibiotic resistant bacteria has generally correlated with the rise and fall of specific antibiotic use in clinical practice. Although the discovery of a new drug temporarily confers therapeutic superiority over bacterial pathogens, the subsequent rapid evolution of resistance limits the duration of the effectiveness of specific agents against pathogens. Surveillance and the development of drug policies that encourage judicious use of antimicrobials will help to minimise the spread of resistant infections. This paper reviews how this dual strategy may be used to control antimicrobial resistance.

Bacterial Infections↗
PubMed1999

The association between antecedent vancomycin treatment and hospital-acquired vancomycin-resistant enterococci: a meta-analysis.

BACKGROUND: The association between vancomycin hydrochloride treatment and vancomycin-resistant enterococci (VRE) has been investigated in numerous studies with variable results. OBJECTIVES: To conduct a meta-analysis to estimate the magnitude of the association between vancomycin treatment and individual risk of VRE and to identify study characteristics that accounted for heterogeneity in study results. METHODS: Studies were identified using MEDLINE with index terms "Enterococcus," "Enterococcus faecalis," or "Enterococcus faecium" and "vancomycin," "drug resistance," "drug resistance, microbial," or "drug resistance, multiple or risk factors." Reports from conferences and reference lists of recent reviews were used. A total of 420 published reports and 98 conference reports were reviewed; 20 studies described in 15 published reports were included in the analysis. We recorded study period, hospital setting, case and control definitions, length of hospital stay, method of adjustment for differences in length of stay, and data on treatment with vancomycin. The odds ratio (OR) of vancomycin treatment provided the measure of association analyzed. A random-effects model was used to estimate the pooled OR. RESULTS: When results from all 20 studies were combined, the pooled OR was 4.5 (95% confidence interval, 3.0-6.9), but the test for heterogeneity was highly significant (P<.001). The 5 studies that used patients with vancomycin-susceptible enterococci as controls found a stronger association (pooled OR, 10.7; 95% confidence interval, 4.8-23.8) than the 15 studies that used controls who had no VRE isolated (pooled OR, 2.7; 95% confidence interval, 2.0-3.8). After restricting the analysis to the latter studies only, no heterogeneity was evident in the unadjusted study results. Patients with VRE had stayed in the hospital much longer than control patients. Studies that adjusted for this difference found only a small and nonsignificant association between vancomycin treatment and VRE (pooled OR, 1.4; 95% confidence interval, 0.74-2.60). We also detected publication bias, favoring report of studies that found a large measure of association. CONCLUSIONS: The reported strong association between vancomycin treatment and hospital-acquired VRE results from the selection of the reference group, confounding by duration of hospitalization, and publication bias. Studies that accounted for these factors found only a small and nonsignificant association.

Adult↗
PubMed1984

The use of antimicrobial drugs in agriculture.

Antibacterial drugs have been used widely in animal production for treatment and prevention of disease and for growth promotion. Concern has been expressed about possible harm to humans, through the use of drugs, in the following ways: increased microbial drug resistance; drug residues in food; allergic reactions and sensitization to antimicrobials; and drug toxicity. Research has shown that microbial resistance in people can develop from drugs used in animals. Farmers, butchers, etc., have been shown to have an increased incidence of drug-resistant organisms. Resistance to antibiotics can develop in two ways; genetic mutation and natural selection, and through R-factor plasmid transfer. Allergic reactions have been reported following the ingestion of penicillin-containing milk; however, residues in other foods have not caused allergic reactions. Sensitization of humans to antimicrobials through the consumption of drug residues in foods has never been documented. Evidence suggests that the residue levels in food are too low to cause sensitization. Drug toxicity, other than allergic reactions, appears not to result from residues of antimicrobial drugs in food. While it has been studied many times, monitoring programs have failed to find any evidence of a problem. This appears to reflect the low toxicity of these agents and the small amounts obtained in the food, however, it could also reflect failure of the monitoring systems.

Agriculture↗
PubMed1963

THE NON-MEDICAL USE OF ANTIBIOTICS AND THE RISK OF CAUSING MICROBIAL DRUG-RESISTANCE.

One of the hazards involved in the use of antibiotics in animal feeds is that it may lead to the development of bacterial drug-resistance. An analysis of the phenomenon shows that this possibility largely depends on the size of the bacterial populations involved and on the possibility of selective multiplication of the resistant mutants that may be present. Additional factors involved in the development of resistance are the type of drug applied and the time during which the bacteria are in contact with it.Animal experiments and general practical experience show that resistance, especially in E. coli, Salm. typhimurium and Staph. aureus, may considerably increase as higher doses are added to the feed. Therefore, the lowest effective level for growth promotion (5-20 p.p.m. of penicillin or tetracycline) is to be preferred over higher levels.AS TO THE PRACTICE OF FOOD PRESERVATION BY MEANS OF ANTIBIOTICS, A DANGEROUS SITUATION MAY ARISE IF TWO FACTORS COMBINE: emergence of bacterial resistance in Salmonella and perhaps other pathogenic bacteria in the animal as a result of the addition of a certain antibiotic to feeds, and subsequent use of the same substance for preservation of the meat.

Animal Feed↗
PubMed1996

Ins and outs of antimicrobial resistance: era of the drug pumps.

Over the past five years, concerns have heightened over the escalating numbers of pathogenic micro-organisms isolated that are resistant to many antibiotics and drugs. This phenomenon poses major problems in the treatment of patients with hospital- or community-acquired infections caused by bacteria, fungi, or parasitic organisms. Microbial cells have acquired resistances to specific antibiotics and drugs by mechanisms that include antibiotic inactivation, target alteration, or drug exclusion. More recently, the importance of another mechanism, that of drug expulsion, has been recognized as contributing significantly to antibiotic and drug resistance in microbes. Drug expulsion, mediated by membrane-associated drug efflux pumps, can protect cells from a range of toxic compounds and therefore may confer single-step multidrug resistance. It is imperative that new drugs be designed or discovered that will poison the pumps or bypass the efflux mechanisms.

Bacterial Infections↗