(1/98) In vitro evaluation of AZD2563, a new oxazolidinone, tested against beta-haemolytic and viridans group streptococci.
Linezolid was the first clinically applied agent from the oxazolidinone class, and AZD2563, a new agent, is described here. Five hundred and twenty-five streptococcal isolates were tested, including beta-haemolytic (266) and viridans group (259) species. MIC(50)/MIC(90)/% susceptible (susceptibility breakpoint <2 mg/L of AZD2563) results were, for beta-haemolytic species: AZD2563 (1/2/100), linezolid (1/2/100), quinupristin-dalfopristin (0.25/0.25/100), vancomycin (0.25/0.5/100) and levofloxacin (0.5/1/99); for viridans group species: AZD2563 (0.5/1/100), linezolid (1/1/100), quinupristin-dalfopristin (0.5/1/99), vancomycin (0.5/0.5/100) and levofloxacin (1/1/98). The modal MICs of AZD2563 and linezolid were 0.5 or 1 mg/L and 1 mg/L, respectively. AZD2563 activity screening against these non-pneumococcal streptococci indicated a slightly greater potency of AZD2563 when compared with linezolid. All AZD2563 MICs were <2 mg/L. (+info)
(2/98) Avoiding the pump in tricuspid valve endocarditis--vegetectomy under inflow occlusion.
BACKGROUND: Surgical treatment of tricuspid valve endocarditis (TVE) ranges from vegetectomy to valve replacement with the use of cardiopulmonary bypass (CPB), accompanied by risks of systemic and lung complications. We present our experience with tricuspid valve vegetectomy under inflow occlusion without CPB. METHODS: Between July 1998 and July 2001, seven patients with a mean age of 26 years underwent tricuspid valve vegetectomy under vena caval inflow occlusion (VCIO). Five patients were intravenous drug users. None of them had left-sided heart valve involvement. The clinical indications for operating were recurrent septic pulmonary emboli with significant bilateral lung infiltrates and intractable infection with signs of severe systemic sepsis, despite treatment with appropriate intravenous antibiotics for a mean duration of 126 hours. The echocardiographic indication was very large localized >1 cm vegetations in all patients. Six patients had methicillin sensitive staphylococcus aureus and one had streptococcus viridans positive blood cultures. Five patients had postoperative high volume veno-venous hemofiltration (HVVF). RESULTS: There were no deaths. VCIO time did not exceed 2 minutes (range time was 45 seconds to 2 minutes). All patients had resolution of sepsis and improvement in respiratory status within 48 hours. Five patients had trivial and two moderate tricuspid regurgitation. Six patients were discharged home within 14 days with no long-term sequelae. One patient required long-term dialysis for renal failure. One patient required a late thoracotomy for drainage of a loculated empyema. CONCLUSIONS: Tricuspid valve vegetectomy can be performed safely under VCIO. HVVF promotes removal of inflammatory mediators, thus improving recovery. (+info)
(3/98) The relative roles of transthoracic compared with transesophageal echocardiography in children with suspected infective endocarditis.
OBJECTIVES: The study evaluated the additional benefit of transesophageal echocardiography (TEE) versus transthoracic echocardiography (TTE) in pediatric cases with suspected bacterial endocarditis. BACKGROUND: In adult patients, TTE has a lower sensitivity and specificity than TEE for the detection of vegetations or aortic root abscess formation. Few data are available about the relative benefits of TEE over TTE in the pediatric age group. METHODS: Patients were included if they had positive blood cultures for typical microorganisms and had a TTE and TEE within 14 days of each other. The patients had to meet the Duke criteria for a positive diagnosis of bacterial endocarditis. The TTE and TEE data were analyzed using the McNemar test for the significance of change. RESULTS: Twenty-one patients fulfilled the criteria, at a median age of 9.5 years. Congenital heart disease was present in 13 patients; 4 patients were previously healthy and 4 patients had other medical problems. Nine patients had surgical confirmation of bacterial endocarditis. Fifteen patients had a positive cardiac finding, with 12 vegetations, 2 vegetations plus aortic root abscess, and 1 isolated abscess. There was excellent agreement between TTE and TEE in those cases with positive cardiac findings, with a p = 0.32, kappa 0.89. Using positive TEE cardiac findings as the gold standard, the sensitivity for TTE was 86% for all 15 events and 93% for the detection of a vegetation. CONCLUSIONS: In pediatric cases, TTE has a high degree of sensitivity for the detection of supportive evidence of endocarditis, and TEE should be reserved for patients with a poor transthoracic window. (+info)
(4/98) Chronic submasseteric abscess: anatomic, radiologic, and pathologic features.
Herein we present five cases of submasseteric abscess that most commonly occurred in patients with a history dental disease. CT has been the main imaging method for diagnosing lesions in the masticator space and adjacent to the mandible; however, we found that, in some of our cases, CT defined the lesion poorly or not at all. In some cases, MR imaging defined the lesion better. Radiologic manifestations of this condition and pathologic correlations are discussed. (+info)
(5/98) Viridans group streptococci are donors in horizontal transfer of topoisomerase IV genes to Streptococcus pneumoniae.
A total of 46 ciprofloxacin-resistant (Cip(r)) Streptococcus pneumoniae strains were isolated from 1991 to 2001 at the Hospital of Bellvitge. Five of these strains showed unexpectedly high rates of nucleotide variations in the quinolone resistance-determining regions (QRDRs) of their parC, parE, and gyrA genes. The nucleotide sequence of the full-length parC, parE, and gyrA genes of one of these isolates revealed a mosaic structure compatible with an interspecific recombination origin. Southern blot analysis and nucleotide sequence determinations showed the presence of an ant-like gene in the intergenic parE-parC regions of the S. pneumoniae Cip(r) isolates with high rates of variations in their parE and parC QRDRs. The ant-like gene was absent from typical S. pneumoniae strains, whereas it was present in the intergenic parE-parC regions of the viridans group streptococci (Streptococcus mitis and Streptococcus oralis). These results suggest that the viridans group streptococci are acting as donors in the horizontal transfer of fluoroquinolone resistance genes to S. pneumoniae. (+info)
(6/98) Transoesophageal echocardiographic diagnosis of aortico-left atrial fistula in aortic valve endocarditis.
Intra-cardiac fistulas are rarely seen and they are estimated to account for <1% of all cases of infective endocarditis. Fistulization of paravalvular abscesses has been found in 6% to 9% of cases. This is a report of an unusual communication between the abscess region in the aortic root and the left atrium. A 44-year-old patient diagnosed with infective endocarditis had continuous fevers despite antibiotic therapy. Transoesophageal echocardiography revealed multiple vegetations on aortic valve, fistulization of an aortic root abscess to the left atrium and mitral regurgitation and moderate aortic regurgitation. At surgery, multiple vegetations on the aortic valve and a large abscess cavity establishing direct communication between aortic root and the left atrial cavity through a fistulous tract were discovered. This experience demonstrates the improved sensitivity and specificity of transoesophageal echocardiography in defining periannular extension of infective endocarditis. (+info)
(7/98) Antimicrobial susceptibility patterns and macrolide resistance genes of viridans group streptococci from normal flora.
OBJECTIVES: Our aim was to study the antimicrobial susceptibilities and macrolide resistance mechanisms of viridans group streptococci isolated from the normal flora. METHODS: In vitro susceptibilities of 16 antimicrobials were studied for 161 viridans streptococci (on average 5.8 isolates per person) from the normal flora of 28 elderly persons. Resistance mechanisms of erythromycin-resistant isolates were studied by the double disc test and PCR. RESULTS: In all, 16.8% of the isolates were non-susceptible (MIC > or =0.25 mg/L) to penicillin, but none showed high-level resistance (MIC > or =4 mg/L). Resistance to erythromycin, tetracycline, quinupristin/dalfopristin, levofloxacin and moxifloxacin was found in 22.4, 27.3, 13.0, 1.9 and 1.9% of the isolates, respectively. Combined resistance to erythromycin and tetracycline was found in 13.0% of the isolates. Erythromycin-resistant isolates were isolated from 57% of the study persons. Of the erythromycin-resistant isolates 80.6% were of the M phenotype and 19.4% were of the macrolide-lincosamide-streptogramin B (MLSB) phenotype (one isolate with constitutive and six with inducible expression). Isolates with the M phenotype were the least susceptible to telithromycin, a new ketolide. The mef(A) gene was found in the isolates with the M phenotype and the erm(B) gene in the isolates with the MLSB phenotype. CONCLUSIONS: The distribution of phenotypes among the viridans streptococci resembles that found in Streptococcus pyogenes, with predominance of the M phenotype. However, the coding gene for the MLSB phenotype, erm(B), is the same in viridans streptococci as in Streptococcus pneumoniae. Viridans group streptococci carrying different resistance traits provide a pool of resistant bacteria that may transfer resistance determinants to more pathogenic organisms. (+info)
(8/98) Genetic characterization of optochin-susceptible viridans group streptococci.
Two clinical isolates of viridans group streptococci (VS) with different degrees of susceptibility to optochin (OPT), i.e., fully OPT-susceptible (Opt(s)) VS strain 1162/99 (for which the MIC was equal to that for Streptococcus pneumoniae, 0.75 micro g/ml) and intermediate Opt(s) VS strain 1174/97 (MIC, 6 micro g/ml) were studied. Besides being OPT susceptible, they showed characteristics typical of VS, such as bile insolubility; lack of reaction with pneumococcal capsular antibodies; and lack of hybridization with rRNA (AccuProbe)-, lytA-, and pnl-specific pneumococcal probes. However, these VS Opt(s) strains and VS type strains hybridized with ant, a gene not present in S. pneumoniae. A detailed characterization of the genes encoding the 16S rRNA and SodA classified isolates 1162/99 and 1174/97 as Streptococcus mitis. Analysis of the atpCAB region, which encodes the c, a, and b subunits of the F(0)F(1) H(+)-ATPase, the target of optochin, revealed high degrees of similarity between S. mitis 1162/99 and S. pneumoniae in atpC, atpA, and the N terminus of atpB. Moreover, amino acid identity between S. mitis 1174/97 and S. pneumoniae was found in alpha helix 5 of the a subunit. The organization of the chromosomal region containing the atp operon of the two Opt(s) VS and VS type strains was spr1284-atpC, with spr1284 being located 296 to 556 bp from atpC, whereas in S. pneumoniae this distance was longer than 68 kb. In addition, the gene order in S. pneumoniae was IS1239-74 bp-atpC. The results suggest that the full OPT susceptibility of S. mitis 1162/99 is due to the acquisition of atpC, atpA, and part of atpB from S. pneumoniae and that the intermediate OPT susceptibility of S. mitis 1174/97 correlates with the amino acid composition of its a subunit. (+info)