[Methicillin-resistant Staphylococcus aureus: 15 years of molecular epidemiology in Western Switzerland]. / Staphylococcus aureus résistant à la méticilline : 15 ans de surveillance moléculaire en Suisse romande.

Since the introduction of antibiotics, successive waves of Staphylococcus aureus clones occurred, each one having characteristic susceptibility pattern to antibiotics and virulence factors. We report here the results of a molecular epidemiological surveillance of methicillin-resistant S. aureus (MRSA) in French-speaking Switzerland between 2006 and 2020 showing the emergence and disappearance of clones known for their international dissemination, and the sporadic appearance of other international clones. Since 2012, a marked decrease in the incidence of cases attributable to the biology of the clones and to the control measures taken in the hospitals has been observed. These results highlight the importance of continuous surveillance in order to better assess the burden of this multi-resistant pathogen in our region.

Depuis l'introduction des antibiotiques, des vagues successives de clones de Staphylococcus aureus sont apparues, chacun avec un profil de susceptibilité aux antibiotiques et de virulence caractéristique. Nous rapportons ici les résultats d'une surveillance épidémiologique moléculaire de S. aureus résistant à la méticilline (MRSA) en Suisse romande entre 2006 et 2020 montrant l'émergence et la disparition de clones connus pour leur dissémination internationale, ainsi que l'apparition sporadique d'autres clones internationaux. Depuis 2012, une diminution marquée de l'incidence des cas attribuable à la biologie des clones et aux mesures de contrôle prises dans les hôpitaux est observée. Ces résultats nous montrent l'importance d'une surveillance continue afin de mieux évaluer le fardeau que représente ce germe multirésistant dans notre région.

Optimal culture incubation time in orthopedic device-associated infections: a retrospective analysis of prolonged 14-day incubation.

Accurate diagnosis of orthopedic device-associated infections can be challenging. Culture of tissue biopsy specimens is often considered the gold standard; however, there is currently no consensus on the ideal incubation time for specimens. The aim of our study was to assess the yield of a 14-day incubation protocol for tissue biopsy specimens from revision surgery (joint replacements and internal fixation devices) in a general orthopedic and trauma surgery setting. Medical records were reviewed retrospectively in order to identify cases of infection according to predefined diagnostic criteria. From August 2009 to March 2012, 499 tissue biopsy specimens were sampled from 117 cases. In 70 cases (59.8%), at least one sample showed microbiological growth. Among them, 58 cases (82.9%) were considered infections and 12 cases (17.1%) were classified as contaminations. The median time to positivity in the cases of infection was 1 day (range, 1 to 10 days), compared to 6 days (range, 1 to 11 days) in the cases of contamination (P < 0.001). Fifty-six (96.6%) of the infection cases were diagnosed within 7 days of incubation. In conclusion, the results of our study show that the incubation of tissue biopsy specimens beyond 7 days is not productive in a general orthopedic and trauma surgery setting. Prolonged 14-day incubation might be of interest in particular situations, however, in which the prevalence of slow-growing microorganisms and anaerobes is higher.

[Quality in microbiology: contribution of the physician]. / Microbiologie de qualité: la contribution du médecin praticien.

It is not always easy to choose the right microbiology test to order. Which pathogens to look for? What is the best-fitted method: microscopy, culture, tests for antigens, antibodies, genes or toxins? How to sample and transport the specimen? This article brings some answers to the questions the physician often asks when prescribing microbiology exams on stools, deep respiratory tract secretions, blood and wounds. By selecting the appropriate tests and respecting the guidelines for sampling and transporting specimens, the physician greatly contributes to the quality of results.