Programme Hospitalier Recherche Clinique, Institut Pasteur, Inserm, French Public Health Agency.
Mycobacterium ulcerans is an emerging environmental pathogen which causes chronic skin ulcers (i.e., Buruli ulcer) in otherwise healthy humans living in tropical countries, particularly those in Africa. In spite of epidemiological and PCR data linking M. ulcerans to water, the mode of transmission of this organism remains elusive. To determine the role of aquatic insects in the transmission of M. ulcerans, we have set up an experimental model with aquariums that mimic aquatic microenvironments. We report that M. ulcerans may be transmitted to laboratory mice by the bite of aquatic bugs (Naucoridae) that are infected with this organism. In addition, M. ulcerans appears to be localized exclusively within salivary glands of these insects, where it can both survive and multiply without causing any observable damage in the insect tissues. Subsequently, we isolated M. ulcerans from wild aquatic insects collected from a zone in the Daloa region of Ivory Coast where Buruli ulcer is endemic. Taken together, these results point to aquatic insects as a possible vector of M. ulcerans.
A new bicolored latex agglutination amoeba test (BLA) for detection of antibodies against Entamoeba histolytica was evaluated for its practicability and diagnostic sensitivity and specificity. BLA is rapid (5 min) and simple to perform. It requires only 20 ,l of a 1/3-diluted serum, 17 ,lI of reagent, and a glass slide. Reading of the test is easy because a positive result shows a green spot with a red surrounding edge. This bicolored pattern is easily distinguishable from the negative test result, which shows a homogeneous dark-brown spot. By using serum samples from 348 individuals, BLA was compared with immunofluorescence assay, indirect hemagglutination, and counterimmunoelectrophoresis. Sensitivity, specificity, efficiency, and positive and negative predictive values of the four methods were almost identical. The results of this study indicate that BLA could be very useful both as a screening method for the diagnosis of invasive amoebiasis and for epidemiological purposes.
Our objective was to compare the ertapenem minimal inhibitory concentrations (MICs) for Enterobacter cloacae isolates categorized intermediate or resistant to ertapenem when measured with the Vitek 2 system, with the MICs for these isolates when measured by two methods performed in agar medium: the Etest and agar plate dilution method (APDM). Overall, 50 E. cloacae isolates were included in the study. The mean MIC of ertapenem was 2.92±1.77μg/ml according to the Vitek 2 system, 0.94±0.84μg/ml according to the Etest strips, and 0.93±0.62μg/ml according to the APDM. Furthermore, the MICs determined by the Vitek 2 system were higher than the MICs determined by the two other methods for 96% of strains. Lastly, according to the Etest strips and APDM, 42% of E. cloacae were susceptible to ertapenem. No carbapenemase was identified by the screening method used. Using the Vitek 2 system to determine ertapenem MICs for E. cloacae can have potential consequences in terms of additional carbapenemase-detecting tests and antimicrobial therapy. It would be interesting to determine if the Vitek 2 system is more effective for the detection of carbapenemase producers with low-level carbapenem resistance than the two methods performed in agar medium.
We describe the first case of Pseudoclavibacter species endocarditis in a 44-year-old patient. This genus, rarely isolated from humans, confirms here its role as a human pathogen. CASE REPORTA 44-year-old man was admitted to Angers University Hospital in November 2013 for a 20-min episode of regular heart flutters and left facial palsy. This patient, a worker in a poultry slaughterhouse, had a history of degenerative mitral valve insufficiency since 2008 and underwent mitral valve repair with an annuloplasty ring (Carpentier-Edwards Phisio II mitral annuloplasty ring; Edwards Lifesciences LLC, Irvine, CA) in 2011. In 2012, he suffered an ischemic cerebrovascular stroke attributed to atrial fibrillation. At the time of admission, the patient had a fever (body temperature, 38.0°C) and was hemodynamically stable. Nothing unusual was noticed in the biological test results, with a normal C-reactive protein level (Ͻ3 mg/liter; reference range, Ͻ5 mg/ liter) and a normal white blood cell count (7 ϫ 10 9 /liter; reference range, 4 ϫ 10 9 to 10 ϫ 10 9 /liter). Cerebral computed tomography showed no recent ischemic or hemorrhagic lesions. Endocarditis was suspected, and transesophageal echocardiography in the emergency department revealed a mitral stenosis and embolizing mitral vegetations, which could explain the transient ischemic attack (1). Five peripheral blood cultures collected in aerobic and anaerobic bottles (BacT/Alert; bioMérieux, Marcy l'Etoile, France) first on admission and then after transfer of the patient to the cardiology department remained sterile after 5 days of incubation. In view of the risk of embolism, 13 days after his admission, he underwent a mechanical bileaflet mitral valve replacement (ATS Medical, Plymouth, MI). Three valve specimens and the removed mitral annuloplasty ring were sent for microbiological analysis. Gram staining of the valve specimens showed short, Gram-positive rods. These samples were cultured on sheep blood agar (COLSϩ; Oxoid, Dardilly, France) in aerobic and anaerobic atmospheres, on chocolate agar (CHOCV; Oxoid), in an air atmosphere with 5% CO 2 , and on Schaedler and brain heart enrichment broths (bioMérieux). Forty-eight hours after inoculation, the culture was positive with little, smooth, gray colonies of nonmotile, catalase-positive, oxidase-negative, coryneform Grampositive rods. The isolate grew on blood and chocolate agars, in an aerobic atmosphere, and in an air atmosphere with 5% CO 2 . No growth was observed under anaerobic conditions. Identification by matrix-assisted laser desorption-ionization time of flight mass spectrometry (Vitek MS; bioMérieux) with the Vitek MS IVD system (database V2.0) or the Vitek MS RUO system (Saramis database) retrieved no identification and no match with any of the species in these databases. The strain was also tested with the Vitek2 phenotypic system (bioMérieux) with the anaerobic bacteriacorynebacterium identification card (ANC card; bioMérieux), but this method failed to identify the strain. The antimicrobial in vitro susc...
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