The objective of the study was to investigate possible changes in cefazolin serum levels induced by cardiopulmonary bypass (CPB). Six cardiac male patients who underwent cardiac surgery requiring CPB ...took part in the study. Cefazolin 2 g was intravenously infused over 60 min before anesthesia and blood samples were taken at appropriate times after drug administration (0, 0.25, 0.5, 1, 4, 6, 8 h), 2 min before and 5 min after the beginning and 2 min before and 5 min after the end of CPB. Drug serum concentrations were determined by means of a microbiological method. Five minutes after the start of CPB, cefazolin serum levels decreased on average by 46.6% and remained steadily low until 5 min after the end of CPB. Then, they rose on average by 37.3% at 4 h and then declined slowly until the last sampling at 8 h. Cefazolin serum concentrations were low during CPB but remained in a potentially effective range for antimicrobial prophylaxis for this surgery.
The identification of bacteria by using conventional microbiological techniques can be very time-consuming and circumstantial. In contrast, the headspace screening of bacterial cultures by analyzing ...their emitted volatile compounds using mass spectrometry might provide a novel approach in diagnostic microbiology. In the present study different strains of Escherichia coli, Klebsiella, Citrobacter, Pseudomonas aeruginosa, Staphylococcus aureus, and Helicobacter pylori were investigated. The volatile compounds emitted by these bacteria in vitro were analyzed using proton-transfer-reaction mass spectrometry, which allows rapid and sensitive measurement. The detected patterns of volatile compounds produced by the investigated bacteria were compared and substantial differences regarding both quantity and quality were observed. In conclusion, the present study is the first to describe headspace screening of bacterial cultures as a potential diagnostic approach in medical microbiology.
The performance of C. difficile toxin A test (Oxoid, Basingstoke, UK), an immunoassay for the detection of C. difficile toxin A in fecal samples, for the diagnosis of C. difficile-associated diarrhea ...was compared with those of cytotoxin assay, culture, and a latex agglutination assay (Culturette Brand CDT Rapid Clostridium difficile test; Becton Dickinson, Cockeysville, MD). A total of 105 stool specimens from 71 patients were tested. Of the 105 specimens analyzed, 6 (5.7%) samples were positive by all four methods, 66 samples (62.9%) were concordant negative. Two patients fulfilled all clinical criteria for C. difficile-associated diarrhea but had negative results in the cytotoxicity tests. The sensitivity and specificity, as determined against cytotoxin assay results, were, respectively 52.4% and 93.9% for latex agglutination, 68.2% and 84.3% for rapid immunoassay and 36.4% and 92.8% for culture. No single laboratory test yields a definitive diagnosis of C. difficile-associated diarrhea at present. Test results by any of these methods must be used in conjunction with patient history when making the diagnosis to avoid indiscriminate treatment of individuals without disease or the lack of treatment for individuals with a serious infection. We consider the rapid and easy-to-perform C. difficile toxin A test not to be an essential adjunct for the diagnosis of C. difficile-associated diarrhea.
Biofilm-associated infections in wounds or on implants are difficult to treat. Eradication of the bacteria is nearly always impossible, despite the use of specific antibiotics. The bactericidal ...effects of high-energy extracorporeal shock waves on Staphylococcus aureus have been reported, but the effect of low-energy shock waves on staphylococci and staphylococcal biofilms has not been investigated. In this study, biofilms grown on stainless steel washers were examined by electron microscopy. We tested ten experimental groups with Staph. aureus-coated washers and eight groups with Staph. epidermidis. The biofilm-cultured washers were exposed to low-energy shock waves at 0.16 mJ/mm(2) for 500 impulses. The washers were then treated with cefuroxime, rifampicin and fosfomycin, both alone and in combination. All tests were carried out in triplicate. Viable cells were counted to determine the bactericidal effect. The control groups of Staph. aureus and Staph. epidermidis revealed a cell count of 6 × 10(8) colony-forming units/ml. Complete eradication was achieved using the combination of antibiotic therapy (single antibiotic in Staph. aureus, a combination in Staph. epidermidis) and shock wave application (p < 0.01). We conclude that shock waves combined with antibiotics could be tested in an in vitro model of infection.
The major drawback in effective use of polymerase chain reaction (PCR) for detectinngMycobacterium tuberculosis(MTB) in clinical samples is the presence of PCR inhibitors and unique cell components ...of the organism that complicate DNA extraction and subsequent PCR amplification. A PCR assay with a unique multistep DNA extraction method that minimizes these problems was compared in a prospective study to acid-fast bacilli stain (AFBS) and culture for detecting MTB in clinical samples. A total of 254 clinical specimens in two separate studies were processed for MTB by these techniques. While PCR and culture were 100% sensitive and specific, culture required up to 8 weeks of incubation and additional time to perform biochemical testing to identify the isolated micro-oganism. Acid-fast bacilli stain had a specificity of about 87% and did not differentiate amongMycobacterialspecies. In contrast, the results from PCR were available within 48 h and did not require additional testing to attain a final result. Polymerase chain reaction was highly reliable for detection and confirmation and interpretation of positive AFBS results. The assay was easy to perform with a turn around time of about 2 days.
Successful treatment of destructive aortic valve endocarditis with annular abscess formation requires extensive surgical debridement and reconstruction of the left ventricular outflow tract and ...aortic root. Homograft aortic roots are the conduits of choice, but because they are not available in all cases, alternative conduits are needed.
Owing to its features, which are comparable to those of homografts, the Freestyle aortic root xenograft was used in 10 consecutive patients aged between 32 and 77 years. All patients had extensive abscess formation, 5 presented with prosthetic valve endocarditis, 2 had additional mitral valve endocarditis requiring partial leaflet resection and reconstruction, 1 patient had an additional fistula into the right atrium, and 1 required coronary bypass. One patient developed a septic ventricular septal defect and fistula into the right atrium with tricuspid valve endocarditis.
None of the patients required reoperation for bleeding. Two (20%) patients died in the postoperative period, 1 due to multiorgan failure, and 1 due to preexisting invasive pulmonary aspergillosis. At autopsy, neither had evidence of intrapericardial hematoma or suture dehiscence. One patient died 13 months postoperatively without clinical signs of valve dysfunction or recurrent endocarditis. All other patients are well at 12 to 42 months after surgery. Clinical examination and echocardiography at the most recent follow-up showed no signs of valve dysfunction, recurrent fistulation, or endocarditis.
The Freestyle aortic root appears to be an acceptable alternative to homografts in the treatment of severe endocarditis. Long-term valve durability in younger patients, however, remains to be determined.
Summary
Group milleri streptococci (GMS) comprise a heterogeneous group of streptococci including the species intermedius, constellatus and anginosus. They may cause chronic intra‐abdominal and ...intrathoracic abscesses, which are difficult to treat. This is a retrospective analysis including 45 transplant recipients in whom GMS were isolated. The epidemiology, clinical significance and the impact on the outcome in all transplant patients with infections caused by GMS during a 4‐year period (2001–2004) was evaluated. The 45 solid organ recipients (88 isolates) included 34 liver‐, four kidney/pancreas‐, one kidney‐, two small bowel‐, three combined liver/kidney‐ and one combined kidney/small bowel transplant recipient. In 42 cases GMS caused intra‐abdominal infection, in two cases pleural empyema and in one case soft tissue infection. Only a single isolate of GMS was cultured from blood. In 54 of the 88 specimens (61%), which grew GMS, other pathogens were also isolated. GMS frequently caused recurrent cholangitis (n = 17) associated with anastomotic and nonanastomotic biliary strictures. These cases were managed by repeated stenting or surgical intervention and prolonged antibiotic therapy. No patient died directly related to GMS infection and all except one case responded to combined surgical/antibiotic treatment. One pancreas graft was lost because of erosion haemorrhage associated with an abscess. GMS were susceptible to penicillin G, carbapenems and clindamycin, whereas cephalosporins and quinolones showed intermediate activity or resistance in some cases, and GMS in general were found resistant to aminoglycosides. GMS may cause serious infections in transplant recipients which are difficult to treat. Their prevalence in transplant surgical site infections thus far may have been underestimated.
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