Elena Alexandrovna Wilson

Effect of beta lactam antibiotic use in children on pneumococcal resistance to penicillin: prospective cohort study.

Abstract Objective: To examine the relation between use of antibiotics in a cohort of preschool children and nasal carriage of resistant strains of pneumococcus. Design and participants: Prospective cohort study over two years of 461 children aged under 4 years living in Canberra, Australia. Main outcome measures: Use of drugs, respiratory symptoms, and visits to doctors were documented in a daily diary by parents of the children during 25 months of observation. Isolates of pneumococci, which were cultured from nasal swabs collected approximately six monthly, were tested for antibiotic resistance. Results: From the four swab collections 631 positive pneumococcal isolates from 461 children were found, of which 13.6% were resistant to penicillin. Presence of penicillin resistant pneumococci was significantly associated with childrens use of a β lactam antibiotic in the two months before each swab collection (odds ratio 2.03 (95% confidence interval 1.15 to 3.56, P=0.01)). The odds ratio of the association remained >1 (though did not reach significance at the 0.05 level) for use in the six months before swab collection. The association was seen in children who received only penicillin or only cephalosporin antibiotics in that period. The odds ratio was 4.67 (1.29 to 17.09, P=0.02) in children who had received both types of β lactam in the two months before their nasal swab. The modelled odds of carrying penicillin resistant pneumococcus was 4% higher for each additional day of use of β lactam antibiotics in the six months before swab collection. Conclusions: Reduction in β lactam use could quickly reduce the carriage rates of penicillin resistant pneumococci in early childhood. In view of the propensity of these organisms to be spread among children in the community, the prevalence of penicillin resistant organisms may fall as a consequence. What is already known on this topic Resistance to pneumococcal antibiotics is increasing worldwide One possible cause of resistance is the excessive use of antibiotics in children with respiratory symptoms Few cross sectional studies have looked at the association between antibiotic use and subsequent carriage of organisms resistant to penicillin What this study adds Carriage of pneumococcus is high in preschool Australian children throughout the year and highest in winter The likelihood of carrying penicillin resistant pneumococcus is doubled in children who have used any β lactam antibiotic in the two months before testing The likelihood of a child carrying a penicillin resistant pneumococcus is increased by 4% for each additional day of β lactam use in the six months before testing

Popularity of less frequent follow up for breast cancer in randomised study: initial findings from the hotline study

Abstract Objective: To compare the experiences of patients with breast cancer who were conventionally monitored with those in whom routine follow up was restricted to the time of mammography. Design: Randomisation to conventional schedule of clinic visits or to visits only after mammography. Both cohorts received identical mammography and were invited to telephone for immediate appointments if they detected symptoms. Setting: Combined breast clinic, Chelsea and Westminster Hospital. Subjects: 211 eligible outpatients with a history of breast cancer. Main outcome measures: Acceptability of randomisation, interim use of telephone and general practitioner, satisfaction with allocation to follow up. Results: Of 211 eligible patients, 196 (93%) opted for randomisation in the study. Of these, 55 were under 50 years, 78 were diagnosed fewer than five years before, 90 had stage T2-4 tumours, and 71 had involved axillary nodes. Patients who did not participate were more likely to be under 50 years, to be two to five years after diagnosis, and to have had aggressive primary disease. Twice as many patients in both groups expressed a preference for reducing rather than increasing follow up. No increased use of local practitioner services or telephone triage was apparent in the cohort randomised to less frequent follow up by specialists. Conclusions: Reducing the frequency of routine follow up has so far proved popular among patients with breast cancer at standard risk in this cohort. A multicentre study is needed to determine the effectiveness and cost-effectiveness of routine follow up with respect to disease outcomes. Key messages Although it is standard practice to advocate routine long term follow up of patients with breast cancer, the effectiveness of non-mammographic follow up has not been assessed in randomised trials A key concern that has delayed the implementation of such trials is whether patients would find symptom driven follow up psychologically acceptable In this study most patients agreed to undergo randomisation to less frequent follow up, though all continued with routine mammographic review After randomisation more patients expressed a desire to reduce further, rather than increase, the frequency of follow up Patients undergoing less frequent review did not increase their use of general practitioner or telephone (hotline) services

Antibiotic resistance in Streptococcus pneumoniae isolated from children.

Objective: To determine the level of antibiotic resistance in pneumoniae (S. pneumoniae) isolated from nasal swabs of healthy children.

Spectral hole burning and Raman heterodyne signals associated with an avoided crossing in the NV centre in diamond

Abstract The nitrogen-vacancy centre in diamond exhibits an avoided crossing of ground state electron spin levels in a magnetic field of ∼1028 G applied along the 〈1 1 1〉 direction. In this paper, the magnetic field dependence of Raman heterodyne signals and the optical transmission at 638 nm in the vicinity of the avoided crossing are reported. It is discussed that the optically induced spin polarization of ground state populations produces anomalous fine structure hole-burning behaviour.

Electromagnetic induced transparency using dressed states

Summary form only given. Observations of electromagnetic induced transparency have been reported for many three bare atomic level systems. In the present work EIT is reported for an entirely different three level scheme where the levels are associated with dressed states. The three dressed levels | 1d >, | 2 d >, | 3 d > are generated from a conventional two level system | 1 >, | 2 > by coupling one of the levels to a third remote level, | 3 > using a strong driving field /spl omega//sub d/. The dressed state EIT phenomenon is observed for spin state transitions in a nitrogen-vacancy colour centre in diamond with all fields in the rf region of the electromagnetic spectrum although measurements involve optical detection.