The susceptibilities of 43 pharyngeal isolates of Capnocytophaga to beta-lactam antibiotics, alone or in combination with beta-lactamase inhibitors, were tested by an agar dilution method. The 34 beta-lactamasepositive strains were highly resistant to beta-lactams, but the intrinsic activities of clavulanate, tazobactam, and sulbactam against Capnocytophaga, even beta-lactamase producers, indicates that these beta-lactamase inhibitors could be used for empirical treatment of neutropenic patients with oral sources of infection.The genus Capnocytophaga is composed of a group of capnophilic, gram-negative fusiform bacteria that are part of the normal oral flora in humans and animals. Capnocytophaga species have been identified as the cause of a variety of infections in immunocompetent hosts (18). In immunocompromised and neutropenic patients, Capnocytophaga spp. have been isolated more frequently from patients with bloodstream infections, including bacteremia (2, 5, 9), and patients with endocarditis (4) with severe chemotherapy-induced ulcerations (8). Variations in the prevalence, number, and proportion of Capnocytophaga spp. have been shown to occur in the dental plaque of pediatric cancer patients undergoing a course of immunosuppressive chemotherapy (22). In general, many antibiotics, including penicillins, clindamycin, macrolides, and quinolones, are effective in treating Capnocytophaga infections (6,10,11,21). However, strains that produce beta-lactamases and that cause septicemia have recently been described (1,7,9,19). These beta-lactamase-producing strains increase the risk of infection in neutropenic patients, especially during chemotherapy. The aim of this study was to determine the susceptibilities of 43 Capnocytophaga strains isolated from neutropenic pediatric patients to beta-lactams and beta-lactamase inhibitors.Forty-three Capnocytophaga strains were isolated by swabbing the throats of pediatric cancer patients undergoing a course of chemotherapy in the Department of Pediatric Oncology at Centre Hospitalier Universitaire Sud (Rennes, France). Two reference strains (Escherichia coli CIP 7624 and Staphylococcus aureus CIP 7625) were also included in the study. Throat samples were collected with sterile swabs, which were immediately taken to the Department of Microbiology, dispersed in sterile distilled water, and inoculated onto TBBP agar (4% Trypticase soy agar supplemented with 5% sheep blood, 0.1% yeast extract [AES Laboratory, Combourg, France], 100 g of polymyxin per ml, 50 g of bacitracin [Sigma] per ml) (15). The agar plates were incubated in a 10% CO 2 atmosphere for 5 days at 37°C. The isolates were identified on the basis of colony morphology, Gram staining, negative catalase and oxidase reactions, and API ZYM profiles (BioMérieux, Marcy l'Etoile, France) (13, 23).All isolates were tested for beta-lactamase production by a chromogenic cephalosporin nitrocefin method (Cefinase; BBL Microbiology Systems, Cockeysville, Md.) by the recommended procedure (Becton Dickinson). The test results we...

Cell components of the dimorphic pathogenic fungus Candida dubliniensis were used to prepare monoclonal antibodies (MAbs). One MAb, designated 12F7-F2, was shown by indirect immunofluorescence to be specific for a surface antigen of Candida dubliniensis yeast cells. No reactivity was observed with other fungal genera or with other Candida species, including Candida albicans, that share many phenotypic features with C. dubliniensis. The use of different chemical and physical treatments for cell component extraction suggested that the specific epitope probably resides on a protein moiety absent from C. albicans. However, we failed to identify the target protein by Western blotting, owing to its sensitivity to heat and sodium dodecyl sulfate. MAb 12F7-F2 was further used to develop a commercial latex agglutination test to identify C. dubliniensis colonies (Bichrodubli Fumouze test; Fumouze Diagnostics). The test was validated on yeast strains previously identified by PCR and on fresh clinical isolates; these included 46 C. dubliniensis isolates, 45 C. albicans isolates, and other yeast species. The test had 100% sensitivity and specificity for C. dubliniensis isolated on Sabouraud dextrose, CHROMagar Candida, and CandiSelect media and 97.8% sensitivity for C. dubliniensis grown on Candida ID medium. The test is rapid (5 min) and easy to use and may be recommended for routine use in clinical microbiology laboratories and for epidemiological investigations.

Candida dubliniensis was first established as a novel yeast species in 1995. It is particularly associated with recurrent episodes of oral candidosis in human immunodeficiency virus (HIV)-infected patients, but it has also been detected at other anatomical sites and at a low incidence level in non-HIV-infected patients. It shares so many phenotypic characteristics with C. albicans that it is easily misidentified as such. No rapid, simple, and commercial test that allows differentiation between C. dubliniensis and C. albicans has been developed, until now. Accurate species identification requires the use of genotype-based techniques that are not routinely available in most clinical microbiology diagnostic laboratories. The present study was designed to evaluate the efficiency of a new test (the immunochromatographic membrane [ICM] albi-dubli test; SR2B, Avrillé, France) to differentiate between C. albicans and C. dubliniensis. The organisms evaluated were strains whose identities had previously been confirmed by PCR tests and freshly isolated clinical strains and included 58 C. albicans isolates, 60 C. dubliniensis isolates, and 82 isolates belonging to other species of yeast. The ICM albi-dubli test is based on the principle of immunochromatographic analysis and involves the use of two distinct monoclonal antibodies that recognize two unrelated epitopes expressed by both species or specific to only one species. The assay requires no complex instrumentation for analysis and can be recommended for routine use in clinical microbiology laboratories. Results are obtained within 2 h and 30 min and are easy to interpret. This evaluation demonstrated the good performance of this immunochromatographic test for C. albicans and C. dubliniensis isolated on Sabouraud dextrose agar, CHOROMagar Candida, and CandidaSelect, with sensitivities and specificities ranging from 93.1 to 100%. These parameters decreased, however, to 91.4% when the test was performed with yeast isolated with Candida ID.

<p>The global COVID-19 pandemic has created an urgent demand for accurate rapid point of care diagnostic tests. Antigen-based assays are suitably inexpensive and can be rapidly mass-produced, but sufficiently accurate performance requires highly-optimized antibodies and assay conditions. An automated liquid handling system, customized to handle lateral flow immunoassay (LFA) arrays, was used for high-throughput antibody screening of anti-nucleocapsid antibodies that will perform optimally on an LFA. Six hundred seventy-three anti-nucleocapsid antibody pairs were tested as both capture and detection reagents with the goal of finding those pairs that have the greatest affinity for unique epitopes of the nucleocapsid protein of SARS-CoV-2 while also performing optimally in an LFA format. In contrast to traditional antibody screening methods (e.g. ELISA, bio-layer interferometry), the methods described here integrate real-time LFA reaction kinetics and binding directly on nitrocellulose. We have identified several candidate antibody pairs that are suitable for further development of an LFA for SARS-CoV-2. </p>

Mouse fibroblasts transformed by murine sarcoma virus (MSV) are highly sensitive to the antiproliferative effect of interferon (IFN) (M. Bakhanashvili, D. H. Wreschner, and S. Salzberg, Cancer Res. 43:1289-1294, 1983). To elucidate the mechanism leading to this IFN sensitivity, the expression of the 2'-5'-oligoadenylate synthetase (2-5A synthetase) gene, the presence of the 2-5A synthetase protein, and the level of its enzymatic activity were determined in IFN-treated and untreated cultures. NIH 3T3 mouse fibroblasts were compared with two different NIH 3T3 clones transformed by MSV. Cultures were treated with 300 IU of beta IFN (IFN-I) per ml for 16 to 24 h. While no detectable 2-5A synthetase-derived transcripts were seen in untreated NIH 3T3 cells, two size classes of RNA transcripts, i.e., 1.7 and 4.2 kilobases, were detected in IFN-treated cultures. Surprisingly, a similar amount of transcripts were present in untreated transformed cells. However, following IFN treatment, an eightfold increase in the level of RNA was readily detected in these cells, with no change in the size classes. Similar results were obtained with the 2-5A synthetase protein, for which three size classes of 42, 71, and 102 kilodaltons were demonstrated by immunoblotting, and with the enzymatic activity, for which again, the highest level was seen in IFN-treated MSV-transformed cultures. The basal level of 2-5A synthetase gene expression in the transformed cells has biological significance since these cells were more resistant to mengovirus infection than NIH 3T3 mouse fibroblasts. Medium collected from transformed cultures failed to induce 2-5A synthetase activity in NIH 3T3 cells. Furthermore, antibodies directed against mouse IFN-4 failed to inhibit 2-5A synthetase activity detected in transformed cultures. These results suggest that at least IFN-,I secretion is not involved in the elevated level of 2-5A synthetase gene expression in these cells.