No abstract available.
Abscess* ; Citrobacter koseri

BACKGROUND: At antimicrobial susceptibility testing (AST), clinical isolates may appear susceptible sometimes to the antibiotics that are clinically ineffective or due to technical errors in the testing. So an interpretive reading of AST should be done, but most hospitals do not perform it routinely. Here, we developed and evaluated a computerized expert system to interpret AST of Enterobacteriaceae to beta-lactam antibiotics. METHODS: We made a rule-based expert system according to the natural resistance of the members of Enterobacteriaceae and the common phenotypes of resistance mechanisms for Enterobacteriacae. Antimicrobial suceptibility testings were performed using the disk diffusion method with 12 beta-lactam antibiotics for a total of 1, 016 clinical isolates. Then we compared the raw and expert results of AST. RESULTS: An overall discrepancy rate due to natural resistance was 5.9%; 10.4% for Klebsiella spp. and Citrobacter diversus, 15.0% for Enterobacter spp., 2.6% for Serratia marcescens, 31.6% for Morganella morganii and Providencia stuartti. Accoriding to acquired antimicrobial resistant mechanisms, overall resistant discrepancy was 21.8%; 18.8% for Escherichia coli, Proteus mirabilis, Salmonella and Shigella spp., 25.9% for Citrobacter diversus and Klebsiella spp., 21.6% for Citrobacter freundii and Enterobacter spp., 45.6% for Morganella morganii, 10.0% for Proteus vulgaris, 12.2% for Serratia spp.. CONCLUSIONS: These results indicate that the application of the expert system for interpretation of antimicrobial susceptibility test may provide more reliable data for the treating physician. Additional information should be applied on the software for new resistant mechanisms or some misinterpretive readings.
Anti-Bacterial Agents ; beta-Lactams* ; Citrobacter freundii ; Citrobacter koseri ; Diffusion ; Enterobacter ; Enterobacteriaceae* ; Escherichia coli ; Expert Systems* ; Immunity, Innate ; Klebsiella ; Morganella morganii ; Phenotype ; Proteus mirabilis ; Proteus vulgaris ; Providencia ; Reading ; Salmonella ; Serratia ; Serratia marcescens ; Shigella

A 54-year-old male patient was seen in clinic for ocular pain and decreased vision in the right eye with duration of two days. He underwent a cataract operation for his right eye 12 years ago, then a sclera-fixated secondary intraocular implantation and pars plana vitrectomy three years ago due to intraocular lens dislocation. At the initial visit, his visual acuity was restricted to the perception of hand motion. An edematous cornea, cells, flare with hypopyon, and exposed suture material at were observed at the six o'clock direction by slit lamp. Vitreous opacity was noted from B-scan ultrasonography. The patient was diagnosed with late-onset endophthalmitis and an intravitreal cocktail injection was done. On the next day, the hypopyon was aggravated, and therefore a pars plana vitrectomy was performed. A vitreous culture tested positive for Citrobacter koseri. After 12 weeks, the best corrected visual acuity of the right eye improved to 0.7 and a fundus examination revealed a relatively normal optic disc and retinal vasculature. We herein report the first case of endophthalmitis caused by Citrobacter koseri in Korea. Exposed suture material was suspected as the source of infection in this case and prompt surgical intervention resulted in a relatively good visual outcome.
Anti-Bacterial Agents/administration & dosage ; Cataract Extraction/adverse effects ; Citrobacter koseri/*isolation & purification ; Diagnosis, Differential ; Endophthalmitis/diagnosis/*microbiology/therapy ; Enterobacteriaceae Infections/diagnosis/*microbiology/therapy ; Eye Infections, Bacterial/diagnosis/*microbiology/therapy ; Follow-Up Studies ; Humans ; Intravitreal Injections ; Lens Implantation, Intraocular/*adverse effects ; Male ; Microscopy, Acoustic ; Middle Aged ; Surgical Wound Infection/diagnosis/*microbiology/therapy ; Sutures/adverse effects/microbiology ; Visual Acuity ; Vitrectomy ; Vitreous Body/*microbiology