Safety of Direct Drug Provocation for the Evaluation of Penicillin Allergy in Low-Risk Adults.

BACKGROUND: About 10% of patients have a penicillin allergy label, but less than 5% of them are actually allergic. Unnecessary penicillin avoidance is associated with serious medical consequences. Given the growing number of these labels, it is imperative that our diagnostic strategy for penicillin allergy be as efficient as possible. The validity of traditionally used skin tests (STs) has been questioned, whereas drug provocation testing (DPT), the criterion standard, without previous ST appears very safe in most cases. OBJECTIVE: To evaluate the safety of direct DPT without consideration for ST results and the validity of ST in the diagnosis of penicillin allergy. METHODS: In this prospective cohort study without a control group, we recruited patients consulting an allergist for penicillin allergy. Patients underwent ST followed by DPT regardless of ST results. Patients with anaphylaxis to penicillin within the past 5 years or a severe delayed reaction were excluded, as were those with significant cardiorespiratory comorbidity. RESULTS: None of the 1002 recruited patients had a serious reaction to DPT. Ten (1.0%) had a mild immediate reaction, of whom only 1 (0.1%) was considered likely IgE-mediated. The positive and negative predictive values of ST for an immediate reaction were 3.6% and 99.1%, respectively. CONCLUSIONS: In a low-risk adult population reporting penicillin allergy, ST has very poor positive predictive value. Direct DPT without ST is safe and appears to be an ideal diagnostic strategy to remove penicillin allergy labels that could be implemented in first-line practice.

Hybridization between char species (Salvelinus alpinus and Salvelinus fontinalis): a fast track for novel allometric trajectories.

Hybridization between closely related species can generate genetic and phenotypic variation, providing valuable biological material to assess the physiological impact of the structural or functional variability of different organs. In the present study, we examined growth rates of various organs and whole body in brook char, Arctic char and their reciprocal hybrids over a period of 281 days. Parental species achieved significantly higher body mass than their hybrids. Hybridization significantly reduced the relative size of the heart, liver and spleen. The relative size of pyloric caeca did not differ among the four groups. The observed lower growth performance of the hybrids compared to parental species strongly suggests that divergence in the relative size of digestive organs, liver and heart partly dictate growth capacity. Our results also suggest that the increased variability achieved through hybridization may prove useful in a genetic selection program.

Safety of Blood Glucose Response Following Exercise Training After Bariatric Surgery.

INTRODUCTION: Safety of exercise training in relationship with the risk of hypoglycemia post-bariatric surgery is unknown. OBJECTIVE: To evaluate the safety and magnitude of changes in blood glucose levels during exercise training following bariatric surgery. MATERIAL AND METHODS: Twenty-nine severely obese patients undergoing either sleeve gastrectomy (SG) (n = 16) or biliopancreatic diversion with duodenal switch (BPD-DS) (n = 13) were prospectively enrolled. Three months after surgery, patients participated in a 12-week supervised exercise training program, (35-min aerobic training with a 25-min resistance exercises) three times a week. Capillary blood glucose (CBG) levels were measured immediately before and after each exercise session. RESULTS: Seven patients (24%) had type 2 diabetes before surgery (mean duration: 10 years); four patients still have type 2 diabetes 3 months post-bariatric surgery. A total of 577 exercise training sessions with CBG monitoring were recorded. Only seven sessions (1.2%) were associated with an episode of asymptomatic hypoglycemia (CBG ≤ 3.9 mmol/L). Patients with type 2 diabetes at baseline showed a larger decrease in CBG with pre-exercise CBG being between 6.1 and 8.0 mmol/L (- 1.6 ± 1.2 vs. - 1.1 ± 0.9 mmol/L, p = 0.02). BPD-DS patients with CBG ≥ 6.1 mmol/L showed higher reduction in CBG following exercise vs. SG patients (- 1.7 ± 1.0 vs. - 1.1 ± 1.1 mmol/L; p < 0.001 and - 4.3 ± 1.0 vs. - 2.2 ± 1.4 mmol/L, p < 0.001, respectively). CONCLUSION: Three months after bariatric surgery, exercise training program in patients without and with type 2 diabetes is safe, and is associated with a desirable glycemic profile, with few episodes of asymptomatic hypoglycemia.

Impact of water quality on the bacterial populations and off-flavours in recirculating aquaculture systems.

A variety of factors affecting water quality in recirculating aquaculture systems (RAS) are associated with the occurrence of off-flavours. In this study, we report the impact of water quality on the bacterial diversity and the occurrence of the geosmin-synthesis gene (geoA) in two RAS units operated for 252 days. Unit 2 displayed a higher level of turbidity and phosphate, which affected the fresh water quality compared with unit 1. In the biofilter, nitrification is one of the major processes by which high water quality is maintained. The bacterial population observed in the unit 1 biofilter was more stable throughout the experiment, with a higher level of nitrifying bacteria compared with the unit 2 biofilter. Geosmin appeared in fish flesh after 84 days in unit 2, whereas it appeared in unit 1 after 168 days, but at a much lower level. The geoA gene was detected in both units, 28 days prior to the detection of geosmin in fish flesh. In addition, we detected sequences associated with Sorangium and Nannocystis (Myxococcales): members of these genera are known to produce geosmin. These sequences were observed at an earlier time in unit 2 and at a higher level than in unit 1. This study confirms the advantages of new molecular methods to understand the occurrence of geosmin production in RAS.

Establishment of a real-time PCR method for quantification of geosmin-producing Streptomyces spp. in recirculating aquaculture systems.

Geosmin and 2-methylisoborneol (MIB) have been associated with off-flavour problems in fish and seafood products, generating a strong negative impact for aquaculture industries. Although most of the producers of geosmin and MIB have been identified as Streptomyces species or cyanobacteria, Streptomyces spp. are thought to be responsible for the synthesis of these compounds in indoor recirculating aquaculture systems (RAS). The detection of genes involved in the synthesis of geosmin and MIB can be a relevant indicator of the beginning of off-flavour events in RAS. Here, we report a real-time polymerase chain reaction (qPCR) protocol targeting geoA sequences that encode a germacradienol synthase involved in geosmin synthesis. New geoA-related sequences were retrieved from eleven geosmin-producing Actinomycete strains, among them two Streptomyces strains isolated from two RAS. Combined with geoA-related sequences available in gene databases, we designed primers and standards suitable for qPCR assays targeting mainly Streptomyces geoA. Using our qPCR protocol, we succeeded in measuring the level of geoA copies in sand filter and biofilters in two RAS. This study is the first to apply qPCR assays to detect and quantify the geosmin synthesis gene (geoA) in RAS. Quantification of geoA in RAS could permit the monitoring of the level of geosmin producers prior to the occurrence of geosmin production. This information will be most valuable for fish producers to manage further development of off-flavour events.