No abstract available.
Citrobacter freundii* ; Citrobacter* ; Osteomyelitis*

No abstract available.
Citrobacter freundii* ; Citrobacter* ; Osteomyelitis*

No abstract available.
Citrobacter freundii* ; Citrobacter* ; Humans ; Infant, Newborn* ; Meningitis*

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

Citrobacter species is a gram-negative bacilli that can cause opportunistic infections in immunocompromised hosts. Citrobacter braakii refers to the genomospecies 6 of the Citrobacter freundii complex. There are no detailed studies on infections caused by this newly identified specific genetic species in Korea. We herein report a case of a patient with hepatocellular carcinoma who, after undergoing transcatheter arterial chemoembolization, developed biloma which later progressed to C.braakii sepsis and did not respond to treatment. To our knowledge, this is the first reported case in Korea on C. braakii infection resulting in septic shock in a patient with malignancy in Korea.
Carcinoma, Hepatocellular ; Citrobacter ; Citrobacter freundii ; Humans ; Immunocompromised Host ; Korea ; Opportunistic Infections ; Sepsis ; Shock, Septic

BACKGROUND: Yersinia pseudotuberculosis is recognized throughout the world as a cause of water-or food born infections in human and animals. Although many attempts have been made to define optimal conditions for the isolation of the organism from water, their isolation yields remain low; therefore, we tried to find an effective method for the recovery of Y. pseudotuberculosis from water. METHODS: Water samples were deliberately contaminated with Y. pseudotuberculosis at various levels and then processed by the following three isolation METHODS: centrifugation, direct filtration, and intracellular culture. For the centrifugation method, the water samples were centrifuged at 5000 rpm for 1 hr and the final precipitates were inoculated in cefsulodin-irgasan-novobiocin(CIN) media. For the filtration method, the water samples were filtered by negative pressure and the filter papers were put directly on CIN media. For the intracellular culture method, the organisms were extracted from the HeLa cells that had been infected with Y. pseudotuberculosis and inoculated on CIN media. We also examined the efficacy of the filtration method after cold enrichment with a mixture of Y. pseudotuberculosis, Escherichia coli, and Citrobacter freundii. RESULTS: With the concentration of 3x10(2)/100 mL, Y. pseudotuberculosis was isolated only by the filtration method; however, none of the culture methods were good enough to recover the organism from the water sample when the concentration was 3x10/100 mL. With cold enrichment, however, the recovery was much more efficient; the organism grew after direct inoculation or after filter inoculation when the starting concentrations were 3x10(2)/100 mL or 3x10/100 mL, respectively. CONCLUSION: A combined use of direct filtration and filter inoculation after cold enrichment is the most effective method to yield Y. pseudotuberculosis isolation. The introduction of effective methods for the isolation of Y. pseudotuberculosis from untreated drinking water would increase the awareness by the public of the health hazard of spring water.
Animals ; Centrifugation ; Citrobacter freundii ; Drinking Water ; Escherichia coli ; Filtration ; HeLa Cells ; Humans ; Water* ; Yersinia pseudotuberculosis* ; Yersinia*

BACKGROUND: Clinical isolates of AmpC beta-lactamase- producing Enterobacteriaceae were evaluated to determine the prevalence of CTX-M extended-spectrum beta-lactamases (ESBLs) and their genetic environments. METHODS: A total of 250 non-duplicate isolates of Eneterobacter aerogenes, E. cloacae, Citrobacter freundii, Serratia marcescens and Morganella morganii were collected at a Korean hospital. ESBL production was determined by double disk synergy test. For ESBL producers, bla genes were sequenced and blaCTX-M environment was characterized by PCR mapping and sequencing. RESULTS: Among the 250 isolates 29 (11.6%) produced ESBL, and 14 of the 29 isolates produced CTX-M ESBLs, including CTX-M-9 by 8 isolates, CTX-M-3 by 4 isolates, CTX-M-12 by 1 isolate, and CTX-M-14 by 1 isolate. ISEcp1 was present upstream of blaCTX-M-3, 12, and 14. Three of the four CTX- M-3 producers had the same genetic environment (pemK-ISEcp1-blaCTX-M-3-orf477-mucA). An IS903-like element was found downstream of blaCTX-M-14. ISCR1 was identified upstream of blaCTX-M-9 and ISCR1 and blaCTX-M-9 were located on sul1-type class 1 integron. The variable region between the 5'-CS and the first 3'-CS contained dfrA16 and aadA2. Its structure was similar to that of In60, but our isolates did not have IS3000 or second 3'-CS. CONCLUSION: CXT-M type ESBL was prevalent in AmpC beta-lactamase-producing Enterobacteriaceae, particularly E. cloacae. blaCTX-M genes were associated with ISEcp1 or ISCR1. This is the first report on the genetic environment of blaCTX-M in Korean isolates.
beta-Lactamases ; Citrobacter freundii ; Cloaca ; Enterobacteriaceae ; Integrons ; Korea ; Morganella morganii ; Polymerase Chain Reaction ; Prevalence ; Serratia marcescens

We evaluated the impact of revised Clinical and Laboratory Standards Institute (CLSI) breakpoints for broad-spectrum cephalosporins (BSCs) on the susceptibilities of 1,742 isolates of Enterobacter species, Serratia marcescens, Citrobacter freundii, and Morganella morganii. The 2011 CLSI criteria for cefotaxime and ceftazidime reduced the rates of susceptibility by 2.9% and 5.9%, respectively. The 2014 CLSI criteria for cefepime reduced the rate of susceptibility by 13.9%, and categorized 11.8% isolates as susceptible-dose dependent (SDD) for cefepime. Among 183 isolates with extended-spectrum ß-lactamase (ESBL) phenotype, implementation of the new criteria reduced the rates of susceptibility to cefotaxime, ceftazidime, and cefepime by 2.8%, 14.8%, and 53.6%, respectively. The proportion of ESBL phenotype among BSC-susceptible isolates was low (0.9% for cefotaxime, 3.0% for ceftazidime, and 3.3% for cefepime). In summary, implementation of new CLSI criteria led to little change in susceptibility to cefotaxime and ceftazidime but a substantial change in susceptibility to cefepime. The recognition of revised CLSI criteria for BSC and SDD will help clinicians to select the optimal antibiotic and dosing regimen.
Cefotaxime ; Ceftazidime ; Cephalosporins ; Citrobacter freundii ; Enterobacter ; Enterobacteriaceae* ; Morganella morganii ; Phenotype ; Serratia marcescens

Objective: To explore the drug resistance mechanism and gene structure characteristics of a carbapenemase-producing novel incompatibility group plasmid pNY2385-KPC from Citrobacter freundii. Methods: A multi-drug resistant strain was obtained from urine samples of patients with fever in the emergency ward of Li Huili Hospital, Ningbo Medical Center. Bacterial species was preliminary identified and finally confirmed by 16S rRNA gene amplification and the average nucleotide identity alignment, respectively. The minimum inhibitory concentrations of the antimicrobial agents were determined by VITEK 2 Compact System. The complete genome sequence was obtained by "third-generation" sequencing methods, and then detailed annotation of gene function and comparative genomic analysis of plasmid structure were carried out by BLASTP/BLASTN, RefSeq, ConservedDomains, ResFinder, Isfinder, etc. Results: The pNY2385-KPC carried by citrobacter freundii NY2385 belonged a novel incompatibility group, and contained bla_KPC-2 and conjugative transfer (type Ⅳ secretory system, T4SS) genes, which could induce conjugative transfer. A total of 15 plasmids of the same type as pNY2385-KPC were retrieved by NCBI, which were from Citrobacter freundii, and the rest were from Serratia marcescens, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Raoultella planticola and other bacteria, and were broad-host-range plasmids. The sequence comparative analysis of all 6 of the novel plasmid from Citrobacter freundii showed that the structure of the novel plasmid had certain conserved property, with Tn6296 variant structure carrying bla_KPC-2, and plasmid pCF1807-3 had both repA_pNY2385-KPC and repA_IncX8. Conclusion: The pNY2385-KPC type plasmids in Citrobacter freundii carried bla_KPC-2 resistance gene, which were divided into two subtypes: repA_pNY2385-KPC single replicator and repA_pNY2385-KPC/repA_IncX8 complex replicator, belonging to broad-host-range plasmids. And as a mobile genetic element, the plasmids promote the spread of bla_KPC-2.
Humans ; Citrobacter freundii/genetics* ; RNA, Ribosomal, 16S/genetics* ; Emergency Service, Hospital ; Escherichia coli ; Genomics