Impact of antibiotics on conjugational resistance gene transfer in Staphylococcus aureus in sewage.

The growing rate of microbial pathogens becoming resistant to standard antibiotics is an important threat to public health. In order to assess the role of antibiotics in the environment on the spread of resistance factors, the impact of subinhibitory concentrations of antibiotics in sewage on gene transfer was investigated using conjugative gentamicin resistance (aacA-aphD) plasmids of Staphylococcus aureus. Furthermore, the concentration of antibiotics in hospital sewage was measured by high-performance liquid chromatography (HPLC)-electrospray tandem mass spectrometry. Several antibiotics were found to be present in sewage, e.g. ciprofloxacin up to 0.051 mgl(-1) and erythromycin up to 0.027 mgl(-1). Resistance plasmid transfer occurred both on solidified (dewatered) sewage and in liquid sewage in a bioreactor with a frequency of 1.1x10(-5)-5.0x10(-8). However, low-level concentrations of antibiotics measured in sewage are below concentrations that can increase plasmid transfer frequencies of gentamicin resistance plasmids of staphylococci

Optimizing antibiotics in residents of nursing homes: protocol of a randomized trial.

BACKGROUND: Antibiotics are frequently prescribed for older adults who reside in long-term care facilities. A substantial proportion of antibiotic use in this setting is inappropriate. Antibiotics are often prescribed for asymptomatic bacteriuria, a condition for which randomized trials of antibiotic therapy indicate no benefit and in fact harm. This proposal describes a randomized trial of diagnostic and therapeutic algorithms to reduce the use of antibiotics in residents of long-term care facilities. METHODS: In this on-going study, 22 nursing homes have been randomized to either use of algorithms (11 nursing homes) or to usual practise (11 nursing homes). The algorithms describe signs and symptoms for which it would be appropriate to send urine cultures or to prescribe antibiotics. The algorithms are introduced by inservicing nursing staff and by conducting one-on-one sessions for physicians using case-scenarios. The primary outcome of the study is courses of antibiotics per 1000 resident days. Secondary outcomes include urine cultures sent and antibiotic courses for urinary indications. Focus groups and semi-structured interviews with key informants will be used to assess the process of implementation and to identify key factors for sustainability

Microbiological aspects and antibiotic therapy of diabetic foot infections

q IMMUNOLOGICAL AND MICROBIOLOGICAL ASPECTS OF DIABETIC FOOT INFECTIONS: Diabetic patients are at increased risk of severe skin and bone infections. Immunological disturbances are reasonable and due to altered specific and unspecific cellular immune responses. Analysis of epidemiology and microbial pathogenicity shows that staphylococci seem to be predestined to induce such infections. Staphylococcus aureus and coagulase-negative staphylococci are able to adhere to the wound ground by a sequela of mechanisms. Initial bacterial adherence is due to hydrophobicity, ion exchanges, and specific binding of bacterial adhesion molecules to cellular receptors. Moreover, staphylococci secrete polysaccharides which form a biofilm together with multilayer cell clusters. The highly structured communities within a biofilm are resistant to distinct immunoeffectors and have a decreased susceptibiliy to antibiotics in vivo.q ASPECTS OF ANTIBIOTIC THERAPY: Assessing the severity of an infection is essential to selecting an antibiotic regimen, the mode of drug administration, and the duration of therapy. Regimens for severe and chronic infections are broader spectrum and often intravenously to obtain high drug concentrations immediately. Infections of the bone often require an antibiotic therapy for > 4 weeks, while a 1- to 2-week therapy for mild to moderate infections has been found to be effective.q CONCLUSIONS: Because of the tremendous progress in diagnostics and therapy of diabetic foot infections, infectious complications can be successfully treated by appropriate wound care, metabolic control, and early surgical and antibiotic intervention. Bacterial biofilms involved into chronic infections are new aspects currently not visualized by clinical therapy. Besides the classic antimicrobial therapy, new concepts of an enzymatic therapy or the inhibition of bacterial "communication" (quorum sensing) are in progress and the hope for the future.

Etiology of acute pharyngitis in children: is antibiotic therapy needed?

Acute pharyngitis is a common upper respiratory tract disease in children. The aim of this study is to find the associated microorganisms and determinate whether antibiotics is needed. This study included a total of 416 children with a diagnosis of acute pharyngitis who were treated in an outpatient clinic In Taipei. Throat swabs for viral and bacterial cultures were taken. Antibiotics were prescribed when bacterial pharyngitis was suspected on the initial visit. The prescription was adjusted according to the results of bacterial culture and clinical manifestations on the second visit 3 to 4 days later. The mean age of the patients was 52.9 +/- 36.9 months. A total of 297 potential pathogens were isolated in 242 patients. Viruses were isolated in 123 (29.6%) patients. Bacteria were isolated in 73 (17.5%) patients, whereas group A streptococci were isolated in only 7 (1.7%) patients. Viruses mixed with bacteria were found in 46 (11.1%) patients. The mean age of patients with viral infections was lower than those with bacterial infections (47.5 +/- 30.4 vs 62.4 +/- 43.7 months, p = 0.01). There was a longer duration of fever in patients older than 2 years with viral isolates (p < 0.01). Antibiotics were prescribed for acute pharyngitis on the first visit in 43 (10.3%) patients, and on the second visit in 19 (4.6%) patients. In children with viral infection, mixed isolates, or no growth, there was significantly less prescription of antibiotics on the second visit. Given the low isolation rate of significant bacterial pathogens, routine throat cultures and antibiotics are not indicated in children with acute pharyngitis

J Infect Dis. 2002 Nov 15;186(10):1430-7. Epub 2002 Oct 23.
Detection of attenuated, noninfectious spirochetes in Borrelia burgdorferi-infected mice after antibiotic treatment.

Xenodiagnosis by ticks was used to determine whether spirochetes persist in mice after 1 month of antibiotic therapy for vectorborne Borrelia burgdorferi infection. Immunofluorescence and polymerase chain reaction (PCR) were used to show that spirochetes could be found in Ixodes scapularis ticks feeding on 4 of 10 antibiotic-treated mice up to 3 months after therapy. These spirochetes could not be transmitted to naive mice, and some lacked genes on plasmids correlating with infectivity. By 6 months, antibiotic-treated mice no longer tested positive by xenodiagnosis, and cortisone immunosuppression did not alter this result. Nine months after treatment, low levels of spirochete DNA could be detected by real-time PCR in a subset of antibiotic-treated mice. In contrast to sham-treated mice, antibiotic-treated mice did not have culture or histopathologic evidence of persistent infection. These results provide evidence that noninfectious spirochetes can persist for a limited duration after antibiotics but are not associated with disease in mice

Does bronchoalveolar lavage enhance our ability to treat ventilator-associated pneumonia in a trauma-burn intensive care unit?

BACKGROUND: Recent literature supports the notion that bronchoalveolar lavage (BAL) in ventilated trauma patients may improve our ability to diagnose and treat ventilator-associated pneumonia (VAP). We hypothesized that BAL would decrease the number of cases of VAP diagnosed and impact our antibiotic use and ventilator days. METHODS: Prospective data on all infectious complications were collected for patients admitted to the trauma-burn service for the year 2001. All VAPs between January 1, 2001, through June 30, 2001, were diagnosed without BAL (No BAL group) using clinical signs of fever, sputum production, leukocytosis, chest radiographs, and sputum culture. After July 1, 2001, VAP was diagnosed with the use of BAL. RESULTS: There were 37 cases of VAP in the No BAL group (11%) and 29 cases of VAP (8%) in the BAL group. There were no statistical differences in Injury Severity Score, hospital length of stay, ventilator days, or mortality between the two groups. The time to initial treatment of VAP was shorter for the BAL group, but did not reach significance. The number of patients who had their VAP pathogens correctly treated with empiric antibiotics was also the same between the two groups. There was no difference in the rate of recurrent pneumonias. The antibiotic costs and respiratory therapy/ventilator costs were not statistically different between the groups for trauma patients, although antibiotic costs were higher for burn patients. CONCLUSION: The routine use of BAL to diagnose VAP in our mixed trauma-burn population did not impact on clinical outcomes or antibiotic use. Our results do not justify the additional costs and potential risks of BAL for all patients. The means of VAP diagnosis may not be as important as choosing the appropriate antibiotics for common VAP organisms in any given intensive care unit

Locally delivered antibodies combined with systemic antibiotics confer synergistic protection against antibiotic-resistant burn wound infection.

BACKGROUND: Nosocomially derived gram-negative infections, particularly from antibiotic-resistant pathogens, are a cause of morbidity in patients with severe burn wounds. METHODS: Locally delivered polyclonal antibodies and systemically infused ceftazidime were combined in a lethal murine burn wound model against a virulent Pseudomonas aeruginosa strain that exhibits intermediate resistance to ceftazidime. RESULTS: Survival was synergistically enhanced in cohorts of burned mice treated both locally (subeschar) with pooled polyclonal human immunoglobulin G (1-mg dose) and intravenously with infused ceftazidime (0.44 mg dose). Enhancement of survival correlated with reduced bacterial quantitation in local and systemic tissue observed in separate burned cohorts. Burned, infected mice treated prophylactically with either individual treatment at the same dose or a combination of both treatments administered systemically showed no survival enhancement as compared with the untreated control group. CONCLUSION: Treatment of antibiotic-resistant burn wound infections with antibiotics together with locally delivered immunoglobulins may improve antibiotic protective effects against antibiotic-resistant pathogens

Good clinical practice in using antibiotics in the hospital. Current status in 207 public and private hospitals in 1999

OBJECTIVES: The purpose of this study was to map activities developed in hospitals to monitor antibiotic usage and evaluate implementation of French guidelines for good clinical practice on use of antibiotics in the hospital setting. METHODS: A questionnaire was mailed to the head of the pharmacy of 300 French hospitals. The questionnaire targeted methods developed to monitor antibiotic usage (antibiotic committees, local recommendations, types of prescription and dispensing, surveillance, information and evaluation activities). RESULTS: The response rate was 69% (207 answers). A local committee supervised antibiotic usage in 49% of the hospitals (nosocomial, drug or antibiotic committees). Local recommendations existed in 120 hospitals (59%) and 42% of the hospitals had a validation process before dispensing drug in accordance with the recommendations. Antibiotic prescription was nominal in 65% of the hospitals and specific monitoring was carried out in 42% of them. Antibiotic consumption was monitored in 80% of the hospitals and resistance was monitored in 53%. Twelve percent of the hospitals used an electronic network to share information on prescription and bacteriological results. Regular internal training existed in 20% of the hospitals and evaluation methods (medical audits, impact measures) in 14%. DISCUSSION: Careful monitoring of antibiotics is implemented in most hospitals. Strict application of guidelines, definition and implementation of indicators, and evaluation methods must be improved. Implementation of better hospital monitoring of antibiotics requires: i) a local consensus to limit the antibiotics available and guidelines to adapt to local infections; ii) dissemination of guidelines and training for prescribers; iii) implementation of a dispensing system to check the validity of prescriptions according to local guidelines; iv) implementation of indicators to monitor bacterial resistance and the volume of antibiotics used.

Caring for a patient with Listeria endocarditis: use of antibiotic desensitization.

Occurrence of Listeria endocarditis is rare, and the mortality rate is high, 100% in untreated cases. The use of antibiotics, specifically ampicillin, is considered a first-line treatment. Coadministration of ampicillin and gentamicin provides a synergistic effect in killing the bacteria. Antibiotics are among the most common causes of hypersensitivity reactions. Of all antibiotics, penicillin is the one that most often causes a reaction. Skin testing adds time until treatment, and all patients with sensitivity to penicillin may not be detected. In the case presented, the patient had antibiotic desensitization with ampicillin. He did not have any allergic reactions to the drug. However, his history of allergy to penicillin was uncertain, so perhaps he did not have a true, serious penicillin allergy. Also, most likely he was anergic and could not mount an immune response to ampicillin, even if truly allergic. Therefore, his response may not be a typical response to antibiotic desensitization. Understanding possible hypersensitivity reactions can help guide the medical and nursing management of patients having antibiotic desensitization

Exploring the variability in antibiotic prescribing profiles among paediatricians from two different areas of Italy.

We carried out a multicentre community-based study in order to describe the antibiotic therapeutic approach of paediatricians from two different areas of Italy in the treatment of respiratory tract infection (RTIs), and to assess which factors are involved in a possible variability of prescribing habits. Forty paediatricians participated in the study between October 1998 and April 1999. They had to complete a questionnaire for each therapeutic intervention resulting in an antibiotic prescription. A logistic regression model was used to identify possible predictors in choosing parenteral antibiotics for the treatment of RTIs. In 2 975 questionnaires of antibiotic treatment, RTIs represented 90.2% of the total antibiotics used. Upper respiratory tract infections were the most commonly treated diagnostic group (59.6%), followed by lower respiratory tract infections (20.4%), and middle ear infections (19.8%). Statistically significant differences between northern and southern Italy were reported in the antibiotic prescription profile and the duration of the therapy. Another marked difference was reported in the frequency of laboratory analysis requests. The logistic regression model indicated that the use of parenteral antibiotics appears significantly related to the type of infections [lower RTIs: (OR: 3.99; 95% CI: 2.49-6.37)], the geographic location [northern Italy: (OR: 0.20; 95% CI: 0.20-0.39)], and the presence of concurrent diseases (OR: 3.21; 95% CI: 1.46-7.02). The lack of adherence to clinical guidelines and the marked variability of antibiotic prescription rates between different areas of the country appear to be related to factors other than bacterial resistance, and highlight the importance of carrying out educational programmes targeted at the national level for improving the antibiotic prescription habits for the treatment of RTIs