[Relevance of ESBL-producing pathogens for clinical surgery: diagnostics, therapy, and prevention]. / Bedeutung ESBL-produzierender Keime für die klinische Chirurgie : Diagnostik, Prävention und Therapie.

BACKGROUND: Multiresistant, extended spectrum beta lactamase (ESBL)-producing pathogens are an increasing problem in daily clinical life. This paper summarizes the development of resistance as well as epidemiology, diagnostics, and treatment of ESBL-producing micro-organisms. We analyzed microbiological data collected at the Grosshadern Clinic in Germany between 1996 and 2007, in order to assess the importance of these micro-organisms to medical practice and surgical care units. PATIENTS AND METHODS: Pathogens were isolated from 28,894 patients with Escherichia coli and 10,903 with Klebsiella pneumoniae pathogens between 1996 and 2006 and tested for ESBL production. For the year 2007 we have analyzed the complete spectrum of ESBL-producing pathogens and their distribution to different departments of the clinic. The agar diffusion test with five cephalosporins and an automated detection system (BD Phoenix) were used for screening purposes. Positive results were verified with the E- and double-disc agar diffusion tests. RESULTS: The most important pathogens isolated from patients were E. coli and K. pneumoniae. Analysis of ESBL-producing E. coli pathogens from 1996 to 2006 showed the prevalence increasing from 0% to 4.1%. For ESBL-producing K. pneumoniae, we also found a prevalence rising from 0.3% in 1996 to 6.6% in 2006. For the year 2007 a further increase in ESBL-producing pathogens was detected, reaching 182 cases, with 118 of ESBL-producing E. coli (5.7 %) and 39 of ESBL-producing K. pneumoniae (7.4%). Of these, 24 cases with E. coli and nine with K. pneumoniae were surgery patients (20% and 23%, respectively). CONCLUSION: The results show an increasing prevalence of ESBL-producing pathogens in hospitalized patients and in surgical departments. The resulting rise in treatment costs and patient risk require thorough knowledge of risk factors, therapy, and preventive measures.

A case-based consiliarius for therapy recommendation (ICONS): computer-based advice for calculated antibiotic therapy in intensive care medicine.

We report here on the system ICONS which utilizes case-based reasoning for medical decision support. As an application domain we have chosen the medical field of 'calculated antibiotic therapy' in an intensive care medicine setting. The system ICONS which runs on a personal computer suggests adequate antibiotic therapy regimen satisfying medical and economic conditions. To speed up the process of finding an adequate antibiotic therapy for a current patient, case-based reasoning is used for finding previously documented similar cases and for modifying them according to the requirements of the current patient. To reduce the memory capacity for the documentation of cases, collections of similar cases are clustered to prototypes. Medical knowledge is represented within a hierarchy of such prototypes and cases and an additional context-sensitive background knowledge-base. A knowledge acquisition tool was programmed that allows revisions of the background medical knowledge-base by simple and comprehensive methods. In addition to the advantage of producing site-specific and time-dependent knowledge, case-based reasoning is a practical method for speeding-up the process of generating and evaluating hypotheses in medical classification tasks.

Computer-aided densitometric analysis of protein patterns of Clostridium difficile.

The applicability of whole-cell protein patterns obtained by sodium dodecylsulfate-polyacrylamide gel electrophoresis as a typing method for Clostridium difficile was examined using a total of 227 strains isolated from 191 patients and their surroundings. Computer-aided densitometric analysis was used to establish a reliable standardization technique with which a large number of protein patterns could be efficiently classified. The normalized tracks could be electronically superimposed and compared to give reproducible results. The influence of sample preparation for electrophoresis was found to be negligible. By this technique 35 subgroups could be differentiated, and further discrimination was possible within each subgroup using minor, even very weak protein bands. Epidemiologically related strains of Clostridium difficile yielded absolutely identical patterns, allowing unequivocal identification. Thus protein electrophoresis combined with densitometric analysis was shown to be useful for typing Clostridium difficile isolates.

[Clostridium difficile and antibiotic-associated colitis in risk patients: 2-month epidemiologic study in an intensive care unit]. / Clostridium difficile und Antibiotika-assoziierte Colitis bei Risikopatienten: Zweimonatige epidemiologische Studie auf einer Intensiveinheit.

A toxin produced by Clostridium difficile has been implicated in the pathogenesis of antibiotic-associated colitis. It is not known how often the microorganism is encountered in Germany particularly in high risk patients. Therefore, following a lethal case of colitis, stool samples of 90 patients and 30 staff members of an intensive care unit were screened routinely for C. difficile over 2 months. The organism was found in 6 of 41 patients treated with antibiotics (14.6%); four of them apparently acquired C. difficile while in hospital whereas in 2 a pre-existing carrier state could not be excluded. Colitis developed in 3 of the 6 patients as judged from endoscopy or a positive cytotoxin assay; in 2 patients (not subjected to endoscopy) colitis was suspected on clinical grounds, and 1 patient became an asymptomatic carrier. C. difficile was not found in 49 patients without antibiotic medication, in the health personal and in 12 patients of a general ward. Patients harbouring C. difficile were clustered in certain bed sites of the unit. Environmental studies recovered the microorganism from bed pan washing machines of bedridden and from toilets of ambulant patients but not from other sites like the hands of the personal. These results suggest that chronic carriers of C. difficile, as far as they are identified by current bacteriological methods, are rare in Germany (not more than 2 out of 132 persons investigated, i.e. 1.5%). The frequent finding of C. difficile in patients treated in certain bed sites supports the view that the infection may be acquired from exogenous sources. Antibiotic-associated colitis should be considered more often when intensive care patients are treated with antibiotics.