Med Decis Making. 2002 Nov-Dec;22(6):498-505.
Antibiotic prescribing decisions of generalists and infectious disease specialists: thresholds for adopting new drug therapies.

Metlay JP, Shea JA, Asch DA.

Center for Health Equity Research and Promotion, Department of Veterans Affairs, University of Pennsylvania, Philadelphia, USA. jmetlaceb.med.upenn.edu

The objective of this study was to examine whether physicians are willing to continue to use older antibiotics in the face of drug resistance in order to preserve newer antibiotics forfuture use. The study was a national sample of 398 generalist physicians and 429 infectious disease (ID) specialists. Clinical vignettes prompted respondents to select the level of resistance to a hypothetical older antibiotic at which they would prefer a newer antibiotic without any current resistance in the treatment of a patient with pneumococcalpneumonia. Vignettes varied in the site of care of the patient as a proxyfor variation in disease severity. Respondents significantly reduced their threshold for switching to a newer antibiotic as disease severityincreased. Generalists were more responsive to disease severity than LD specialists. Thus, the adoption of recommendations to limit overuse of newer antibiotics may be variable across clinical settings and providers, reducing the impact of these recommendations on emerging resistance.


Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12458980&dopt=Abstract antibiotic, antibiotics



Br J Dermatol. 2002 May;146(5):840-8.
Prevalence of antibiotic-resistant propionibacteria on the skin of acne patients: 10-year surveillance data and snapshot distribution study.

Coates P, Vyakrnam S, Eady EA, Jones CE, Cove JH, Cunliffe WJ.

The Skin Research Centre, Division of Microbiology, School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.

BACKGROUND: Cutaneous propionibacteria are implicated in acne pathogenesis, although their exact role in the genesis of inflammation is still poorly understood. Agents, including antibiotics, that reduce the numbers of propionibacteria on skin are therapeutic. Resistance in the target organism is a well-recognized consequence of antibiotic therapy for acne but formal prevalence and distribution data are lacking. OBJECTIVES: To monitor the prevalence of skin colonization by antibiotic-resistant propionibacteria in acne patients attending the dermatology out-patient clinic at Leeds General Infirmary over a 10-year period beginning in 1991, and to examine the distribution of resistant strains on acne-prone skin and in the nares. METHODS: Propionibacterial samples were obtained from the skin surface of the worst affected site (usually the face) of 4274 acne patients using a moistened swab. The swab was used to inoculate agar plates with and without selective antibiotics. After anaerobic incubation at 37 degrees C for 7 days, the amount of growth in the presence of each antibiotic was scored on a scale from 0 to 5+. A small number of patients (72) were selected for more detailed quantitative sampling at six different sites to examine the distribution of resistant propionibacteria on acne-prone skin and in the anterior nares. RESULTS: The proportion of patients carrying strains resistant to one or more commonly used antiacne antibiotics rose steadily from 34.5% in 1991 to a peak of 64% in 1997. The prevalence dropped to 50.5% during 1999 and then rose again to 55.5% in 2000. Resistance to erythromycin was the most common and the majority of erythromycin-resistant strains were cross-resistant to clindamycin. Resistance to tetracyclines was less common in all years and with little increase over time. The more detailed quantitative study in 72 patients showed that population densities of resistant propionibacteria varied considerably between sites and between individuals. Almost invariably, patients were colonized with resistant strains at multiple sites, including the nares. CONCLUSIONS: Skin colonization with antibiotic-resistant propionibacteria is much more common now than a decade ago. Resistant propionibacteria are widely distributed on acne-prone skin and in the nares. This suggests that they will be very difficult to eradicate using existing therapeutic regimens, especially from the nasal reservoir.


Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12000382&dopt=Abstract antibiotic, antibiotics



J Palliat Care. 2002 Spring;18(1):25-8.
Antibiotic use in the last week of life in three different palliative care settings.

Oneschuk D, Fainsinger R, Demoissac D.

The purpose of this study was to examine the frequency and types of antibiotics prescribed in the last week of life in three different palliative care settings, including an acute care hospital, tertiary palliative care unit, and three hospice units. A total of 150 consecutive patients were evaluated, 50 in each of the three settings. Twenty-nine patients (58%) in the acute hospital setting, 26 (52%) in the tertiary palliative care unit, and 11(22%) in the hospice settings were prescribed antibiotics. In the acute care and tertiary palliative care settings, the most frequent route of antibiotic administration was intravenous and, in the hospice setting, oral. We conclude that there is marked variability in the numbers and types of antibiotics prescribed in these different palliative care settings in the last week of life. The high use of intravenous antibiotics and the large number of patients who were still receiving antibiotics at the time of death indicate the need for further prospective studies.


Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12001399&dopt=Abstract antibiotic, antibiotics



Cent Afr J Med. 2000 Nov;46(11):296-300.
Antibiotic sensitivity and plasmid profiles of Pseudomonas aeruginosa.

Igumbor E, Gwanzura L, Chirara M, Obi C, Muza D, Chihara M.

Department of Medical Microbiology, School of Medicine, Avondale, Harare, Zimbabwe.

OBJECTIVE: To determine the susceptibility of Pseudomonas aeruginosa to commonly used antibiotics and to study the relationship between antibiotic resistance and the plasmid profiles of the organism. DESIGN: Cross sectional study SETTING: Samples of burns, wound pus, urine, blood, sputum, stool and aspirates were obtained from Harare Hospital (n = 120) and Parirenyatwa Hospital(n = 80). SUBJECTS: Male and female patients either admitted or attending clinics. MAIN OUTCOME MEASURES: P. aeruginosa isolates obtained were resistant to commonly used antibiotics in this environment. The resistance may be plasmid-dependent. RESULTS: P. aeruginosa is prevalent in burns (76.7%) and wounds (67.5%) and in their respective hospital wards. The isolates of P. aeruginosa were resistant to gentamicin (65.5%); carbenicillin (61.9); polymyxinb (53.0%); ciprofloxacin (61.1%) and ceftriazone (70.8%); but showed high sensitivity to tazocin (89.4%) and nalidixic acid (59.3%) and cotrimoxazole (54.9%). All the isolates resistant to the antibiotics tested possessed plasmid DNA. Strains with four plasmids of molecular weight of approximately, 1.5 x 10(6), 1.8 x 10(6), 2.9 x 10(6) and 7.4 x 10(6) Da showed multiple resistance to the drugs that were tested. CONCLUSION: This study reveals an emergence of multiple antibiotic-resistant strains of P. aeruginosa. The traditional drugs gentamicin, carbenicillin, ciproflaxacin, and polymyxin-b used for treatment of P. aeruginosa infections may no longer be reliable. Therefore, a newer drug such as tazocin and other rarely used drugs such as nalidixic acid should be considered for P. aeruginosa antibiotic therapy.


Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12002119&dopt=Abstract antibiotic, antibiotics



J Antimicrob Chemother. 2002 May;49(5):769-75.
Composition and antibiotic resistance profile of microcosm dental plaques before and after exposure to tetracycline.

Ready D, Roberts AP, Pratten J, Spratt DA, Wilson M, Mullany P.

Department of Microbiology, Eastman Dental Hospital, University College London Hospitals NHS Trust, UK. dreadastman.ucl.ac.uk

The aim of this study was to investigate the effects of tetracycline administration on the viability and antibiotic resistance profiles of microcosm dental plaques. A constant depth film fermenter was used to generate multi-species biofilms, which were grown for 216 h before tetracycline was added. The composition of the microcosm plaques was determined by viable counting on selective and non-selective media. The prevalence of antibiotic-resistant organisms was determined on antibiotic-containing media. Before administration of tetracycline, the biofilms had a total viable anaerobic count of 7 x 10(7) cfu per biofilm. They contained 7% lactobacilli, 19% streptococci and 2% Actinomyces spp. Immediately after pulsing with tetracycline, the composition of the biofilms changed and they consisted of 30% lactobacilli, 1.5% streptococci and 3% Actinomyces spp., with a total anaerobic count of 1 x 10(7) cfu per biofilm. The pre-valence and composition of the antibiotic-resistant microflora changed dramatically after the addition of tetracycline, with the proportion of the microflora displaying resistance to tetracycline increasing from 6% to 45%. Corresponding changes in the proportions of the microflora displaying resistance to other antibiotics were as follows: 5-28% for erythromycin, 1-5% for vancomycin and 0.4-3% for ampicillin. The results of this study have shown that the addition of tetracycline to microcosm dental plaques alters their composition and enriches for bacteria resistant to tetracycline and other unrelated agents.


Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12003970&dopt=Abstract antibiotic, antibiotics



EMBO J. 2002 May 15;21(10):2323-31.
Substrate promiscuity of an aminoglycoside antibiotic resistance enzyme via target mimicry.

Fong DH, Berghuis AM.

Department of Biochemistry, McGill University, 3775 University Street, Montreal, Quebec H3A 2B4, Canada.

The misuse of antibiotics has selected for bacteria that have evolved mechanisms for evading the effects of these drugs. For aminoglycosides, a group of clinically important bactericidal antibiotics that target the A-site of the 16S ribosomal RNA, the most common mode of resistance is enzyme-catalyzed chemical modification of the drug. While aminoglycosides are structurally diverse, a single enzyme can confer resistance to many of these antibiotics. For example, the aminoglycoside kinase APH(3')-IIIa, produced by pathogenic Gram-positive bacteria such as enterococci and staphylococci, is capable of detoxifying at least 10 distinct aminoglycosides. Here we describe the crystal structures of APH(3')-IIIa in complex with ADP and kanamycin A or neomycin B. These structures reveal that the basis for this enzyme's substrate promiscuity is the presence of two alternative subsites in the antibiotic binding pocket. Furthermore, comparison between the A-site of the bacterial ribosome and APH(3')-IIIa shows that mimicry is the second major factor in dictating the substrate spectrum of APH(3')-IIIa. These results suggest a potential strategy for drug design aimed at circumventing antibiotic resistance.


Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12006485&dopt=Abstract antibiotic, antibiotics



Pharmacotherapy. 2002 May;22(5):578-85.
Effect of antibiotics on polymorphonuclear neutrophil apoptosis.

Healy DP, Silverman PA, Neely AN, Holder IA, Babcock GE.

College of Pharmacy, University of Cincinnati, OH 45267, USA.

STUDY OBJECTIVE: To evaluate the effects of various antibiotics-direct and indirect as a result of bacterial killing-on polymorphonuclear neutrophil (PMN) apoptosis. DESIGN: In vitro analysis. SETTING: Research laboratory. INTERVENTION: Whole blood collected from healthy human subjects was incubated with and without Klebsiella pneumoniae (1.0 x 10(5) colony-forming units [cfu]/ml) plus ceftazidime 50 microg/ml, gentamicin, ciprofloxacin, trovafloxacin, tetracycline, doxycycline, erythromycin, azithromycin (each 5 microg/ml), or lipopolysaccharide 10 microg/ml. After staining with fluorescein-conjugated annexin V, red blood cells were lysed, and the remaining white blood cells were assessed by flow cytometry with gating on PMNs. MEASUREMENTS AND MAIN RESULTS: In the absence of K. pneumoniae infection, antibiotic exposure directly decreased PMN apoptosis by 17.8% (range -25.0% to -13.9%, p=0.008) compared with untreated cells. In the presence of K. pneumoniae, all antibiotic treatments, even those with poor in vitro activity for the bacterial isolate, decreased PMN apoptosis by 26.2% (range -38.0% to -17.8%, p<0.001) compared with untreated control cells and by 36.6% compared with untreated (no antibiotic) K. pneumoniae-stimulated cells (range -46.2% to -28.0%, p<0.001). CONCLUSIONS: All tested antibiotics in clinically relevant concentrations resulted in modest yet consistent decreases in PMN apoptosis. The magnitude of this change increased slightly in the presence of K. pneumoniae infection. In vivo studies are needed to determine whether antibiotic-associated prolongation of PMN survival improves host response to infection.


Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12013356&dopt=Abstract antibiotic, antibiotics