With fluoroquinolone monotherapy, there was significant association between the MIC of the antimicrobial prescribed and the clinical outcome with all bacteria except CNS and Streptococcus spp. The approach used in this study, if used prospectively, could allow topical breakpoint susceptibility concentrations to be determined for individual antimicrobial and bacterial combinations.

SummaryBackgroundAntimicrobial resistance is a serious threat to public health, with most antibiotics prescribed in primary care. General practitioners (GPs) report defensive antibiotic prescribing to mitigate perceived risk of future hospital admission in children with respiratory tract infections. We developed a clinical rule aimed to reduce clinical uncertainty by stratifying risk of future hospital admission.Methods8394 children aged between 3 months and 16 years presenting with acute cough (for ≤28 days) and respiratory tract infection were recruited to a prognostic cohort study from 247 general practitioner practices in England. Exposure variables included demographic characteristics, parent-reported symptoms, and physical examination signs. The outcome was hospital admission for respiratory tract infection within 30 days, collected using a structured, blinded review of medical records.Findings8394 (100%) children were included in the analysis, with 78 (0·9%, 95% CI 0·7%–1·2%) admitted to hospital: 15 (19%) were admitted on the day of recruitment (day 1), 33 (42%) on days 2–7; and 30 (39%) on days 8–30. Seven characteristics were independently associated (p<0·01) with hospital admission: age <2 years, current asthma, illness duration of 3 days or less, parent-reported moderate or severe vomiting in the previous 24 h, parent-reported severe fever in the previous 24 h or a body temperature of 37·8°C or more at presentation, clinician-reported intercostal or subcostal recession, and clinician-reported wheeze on auscultation. The area under the receiver operating characteristic (AUROC) curve for the coefficient-based clinical rule was 0·82 (95% CI 0·77–0·87, bootstrap validated 0·81). Assigning one point per characteristic, a points-based clinical rule consisting of short illness, temperature, age, recession, wheeze, asthma, and vomiting (mnemonic STARWAVe; AUROC 0·81, 0·76–0·85) distinguished three hospital admission risk strata: very low (0·3%, 0·2–0·4%) with 1 point or less, normal (1·5%, 1·0–1·9%) with 2 or 3 points, and high (11·8%, 7·3–16·2%) with 4 points or more.InterpretationClinical characteristics can distinguish children at very low, normal, and high risk of future hospital admission for respiratory tract infection and could be used to reduce antibiotic prescriptions in primary care for children at very low risk.FundingNational Institute for Health Research (NIHR).

Summary.A nested polymerase chain reaction (PCR) test targeting Aspergillus spp. large ribosomal subunit genes was evaluated retrospectively on 175 serum samples from 37 bone marrow transplant recipients, 70% of whom received grafts from unrelated donors. Six patients had proven infection, seven had probable infection, and three had possible infection, using the revised EORTC case de®nitions. These 16 patients were all PCR positive (57 out of 93 samples tested). Two additional patients who did not ful®l current diagnostic criteria, but in whom invasive aspergillosis (IA) was thought clinically probable, were also PCR positive (®ve out of nine samples). Invasive aspergillosis was unlikely in the remaining 19 patients, four of whom were PCR positive on a single occasion (four out of 70 samples).Three samples were inhibitory to PCR. Sensitivity of PCR in diagnosing patients with IA was 100%, speci®city was 79% and positive predictive value was 80%, using the criterion of a single positive result. If two positive results were required, these values were 81%, 100% and 100% respectively. The median duration of infection documented by PCR was 36 days (range 3±248 days) in 17 out of 18 patients (94%) who did not survive. Positive PCR results predated the institution of antifungal therapy in two-thirds of patients. Four patients became PCR positive during pretransplant conditioning therapy.

A medium for the isolation and enumeration of Malassezia furfur is described. Incubation at 34°C yielded geometric mean counts (in CFU per square centimeter) of 2.6 x 103 on the forehead, 8.5 x 102 on the cheek, and 9.6 x 103 on the back. These counts compared favorably with microscopic counts and greatly exceeded those obtained with previously described media.

A method allowing isolation and microbiological analysis of individual pilosebaceous units (follicles) was used to study biopsies of back skin obtained from volunteer acne vulgaris patients. The main microbial groups isolated were members of the genera Propionibacterium, Staphylococcus and Pityrosporum. The incidence (and mean density) of these organisms in 140 normal follicles was 12% (2.6 x lo5 per follicle), 4% (5.5 x lo3 per follicle) and 13% (lo2 per follicle) respectively. Colonized follicles were not distributed evenly amongst the subjects studied. The results are analysed and discussed from an ecological standpoint.

Seventy one papules in the early stages of inflammatory development were isolated from acne vulgaris affected skin and their content of micro-organisms characterized. The progress of lesions prior to excision was monitored by tracing an area of the upper back onto a transparent acetate sheet. This template was used the next day, and in some cases after 3 days, to identify inflamed lesions of less than 1 day and 2-3 days duration. These were biopsied, and pilosebaceous units isolated by micro-dissection, homogenized and microbial populations studied by viable counting and microscopy. Propionibacteria colonised 68% of '1 day' duration lesions and 79% of '3 day' duration lesions; staphylococci colonized 19% and 32% respectively and Pityrosporum spp. (Malassezia furfur) were found in 52% and 68%. Although the prevalence of each microbial group was higher in the more chronic lesions, these differences were not statistically significant. The microbial profile of inflamed lesions was similar both qualitatively and quantitatively to non-inflamed lesions studied previously. These results call into question the role of micro-organisms as the initiators of inflammation in acne vulgaris.

The prevalence and abundance of Malassezia furfur on clinically normal skin at 20 sites has been determined. All of the 16 subjects studied (young adults) had high counts on the upper trunk and on at least one site on the head. Counts obtained from the lower trunk and upper thighs of male subjects were considerably higher than those from female volunteers. Organisms isolated, grouped according to their colony morphologies, had distributions consistent with those noted for 'Pityrosporum ovale' and 'P. orbiculare' in previous studies. Mean M. furfur counts were compared with aerobic and anaerobic bacterial counts performed at the same sites. Propionibacteria and M. furfur distributions were similar but not identical. Some factors which might limit the range of M. furfur are discussed.

Laser irradiation produces bactericidal effects which may be of use in dentistry. The aims of this study were to investigate the effect of pulsed NdYAG laser irradiation on bacteria in a laboratory model, in the presence and absence of a black dye, Suomi ink. The experiments were carried out in small capillary tubes containing a measured volume of Enterococcus faecalis broth culture. This model simulated the number of organisms that could be expected to occur in an infected root canal. Laser irradiation was delivered from a NdYAG laser via a 320-microns fibre. Powers of 0.3 to 3.0 W were used for 20 to 60 s. Controls received no irradiation. The effect of the black dye was investigated by the addition of a fixed volume to the culture before lasering. The treatments were evaluated for bactericidal effect by comparing the number of viable bacteria remaining in the irradiated and the control specimens. At energy doses of 54 J and above, without black dye, a reduction of 10,000-fold or greater occurred. A similar reduction was achieved at energies above 25 J when black dye was added. These results indicate the energy levels which should be investigated to assess the potential role of the NdYAG laser in endodontics.