No abstract available.
Bacteremia/*microbiology ; *Cephalosporin Resistance ; Escherichia coli/*physiology ; Female ; Humans ; Klebsiella pneumoniae/*physiology ; Male

The third generation cephalosporin is widely used in treatment of spontaneous bacterial peritonitis (SBP). Resistance to the third generation cephalosporin was associated with poor outcome in patients with SBP. Thus it is necessary to know the changes in resistance rate. We planned to investigate retrospectively on resistance rate of the third generation cephalosporin of gram negative bacteria isolated in patients with SBP, who visited Seoul National University Hospital between 1998 and 2006. The Clinical and Laboratory Standards Institute guidelines were applied for antibiotic susceptibility test. A total of 269 consecutive episodes of clinically and microbiologically proven SBP was identified during the study period and 209 cases were caused by gram negative organisms. Among 209 isolates, 22 (10.5%) showed resistance to the third generation cephalosporin. The prevalence of resistance was decreasing during the study period (P=0.014).
Cephalosporin Resistance ; Gram-Negative Bacteria* ; Humans ; Liver Cirrhosis ; Peritonitis* ; Prevalence ; Retrospective Studies ; Seoul

The third generation cephalosporin is widely used in treatment of spontaneous bacterial peritonitis (SBP). Resistance to the third generation cephalosporin was associated with poor outcome in patients with SBP. Thus it is necessary to know the changes in resistance rate. We planned to investigate retrospectively on resistance rate of the third generation cephalosporin of gram negative bacteria isolated in patients with SBP, who visited Seoul National University Hospital between 1998 and 2006. The Clinical and Laboratory Standards Institute guidelines were applied for antibiotic susceptibility test. A total of 269 consecutive episodes of clinically and microbiologically proven SBP was identified during the study period and 209 cases were caused by gram negative organisms. Among 209 isolates, 22 (10.5%) showed resistance to the third generation cephalosporin. The prevalence of resistance was decreasing during the study period (P=0.014).
Cephalosporin Resistance ; Gram-Negative Bacteria* ; Humans ; Liver Cirrhosis ; Peritonitis* ; Prevalence ; Retrospective Studies ; Seoul

BACKGROUND: The therapeutic option is limited for the infections caused by organisms producing plasmid- mediated AmpC beta-lactamases, increasingly identified worldwide. Two sporadic patients with bacteremia caused by K. pneumoniae possessing an unusual inducible beta-lactam resistant phenotype were found in a university hospital. RESULTS:We conducted antibiotic susceptibility test according to NCCLS guideline. Also, we characterized beta-lactamase by isoelectric focusing. RESULTS: DHA-1 gene conferred the resistant phenotype. The patients had experienced treatment failure when treated with extended-spectrum cephalosporin. For the isolates the cephalosporin resistance was induced by clavulanic acid (and cefoxitin). CONCLUSION: Theses results suggest that the extended-spectrum cephalosporins might not provide optimal therapeutic option for inducible DHA-1-producing K. pneumoniae infection, even when the pathogens are susceptible in vitro.
Bacteremia ; beta-Lactamases* ; Cephalosporin Resistance ; Cephalosporins ; Clavulanic Acid* ; Humans ; Isoelectric Focusing ; Klebsiella pneumoniae* ; Klebsiella* ; Phenotype ; Pneumonia ; Treatment Failure

BACKGROUND: The therapeutic option is limited for the infections caused by organisms producing plasmid- mediated AmpC beta-lactamases, increasingly identified worldwide. Two sporadic patients with bacteremia caused by K. pneumoniae possessing an unusual inducible beta-lactam resistant phenotype were found in a university hospital. RESULTS:We conducted antibiotic susceptibility test according to NCCLS guideline. Also, we characterized beta-lactamase by isoelectric focusing. RESULTS: DHA-1 gene conferred the resistant phenotype. The patients had experienced treatment failure when treated with extended-spectrum cephalosporin. For the isolates the cephalosporin resistance was induced by clavulanic acid (and cefoxitin). CONCLUSION: Theses results suggest that the extended-spectrum cephalosporins might not provide optimal therapeutic option for inducible DHA-1-producing K. pneumoniae infection, even when the pathogens are susceptible in vitro.
Bacteremia ; beta-Lactamases* ; Cephalosporin Resistance ; Cephalosporins ; Clavulanic Acid* ; Humans ; Isoelectric Focusing ; Klebsiella pneumoniae* ; Klebsiella* ; Phenotype ; Pneumonia ; Treatment Failure

BACKGROUND: Although healthcare-associated (HCA) Klebsiella pneumoniae bacteremia constitutes a significant proportion of community-onset infection cases, its clinical and microbiologic characteristics have yet to be described in detail. In this study, we sought to delineate the clinical differences between community-associated (CA) and HCA K. pneumoniae bacteremia. MATERIALS AND METHODS: A total of 240 patients infected by community-onset K. pneumoniae bacteremia were included in this study, and the data from the patients with HCA K. pneumoniae bacteremia were compared to those with the CA bacteremia. Isolates were microbiologically characterized and serotyped using a PCR method. RESULTS: Of the total 240 patients infected with community-onset K. pneumoniae bacteremia, 140 (58.3%) were defined as HCA infection cases, and the remaining 100 patients were classified as CA infections. Multivariate analysis showed that use of percutaneous tubes, occurrence of a recent surgical operation, cases of pneumonia, neutropenia and solid tumor, and prior receipt of antibiotics were all significant factors associated with HCA bacteremia infection (all P<0.05). In terms of microbiologic characteristics, ciprofloxacin resistance (12.9% [18/140] vs. 4.0% [4/100], P=0.02) and extended-spectrum beta-lactamase production (12.1% [17/140] vs. 4.0% [4/100], P=0.03) were more common in HCA bacteremia than CA bacteremia, respectively. The K1 and K2 serotypes, which are considered virulent community strains, were observed to exist more frequently in CA bacteremia than in HCA bacteremia (34% [34/100] vs. 21.4% [30/140], P=0.03). The overall 30-day mortality of the study population was 17.5% (37/211), and there was a trend toward greater mortality in the HCA group than in the CA group (21.4% [27/126] vs. 11.8% [10/85]; P=0.07). CONCLUSIONS: Patients infected with HCA bacteremia accounted for a substantial proportion of all patients with community-onset K. pneumoniae bacteremia, and showed significantly different clinical and microbiological characteristics than those infected with CA bacteremia. HCA K. pneumoniae bacteremia represented a distinct subset of community-onset bacteremia characterized by antibiotic resistant pathogens, a finding which physicians should consider in providing optimal treatment of these cases.
Anti-Bacterial Agents ; Bacteremia ; beta-Lactamases ; Cephalosporin Resistance ; Ciprofloxacin ; Community-Acquired Infections ; Humans ; Klebsiella ; Klebsiella pneumoniae ; Multivariate Analysis ; Neutropenia ; Pneumonia ; Polymerase Chain Reaction

OBJECTIVETo investigate the mechanism of carbapenems resistance in Acinetobacter baumannii.

METHODSWHONET-5 software was used to analyze the trend of carbapenem resistance in Acinetobacter baumannii collected from 1999 to 2001 at Peking Union Medical College Hospital. Analytical isoelectric focusing was used to measure the pI of the beta-lactamase. Conjugation experiment was used to study the transfer of carbapenem resistance and plasmid DNA was extracted and purified with Qiagen Plasmid Mini Kit. The homology of the isolates was determined by pulsed field gel electrophoresis (PFGE). Integrase genes and blaIMP-, blaVIM-, blaOXA- genes for resistant isolates were amplified and sequenced.

RESULTSImipenem resistance in A. baumannii was ranged from 1.8%-8.5%, but only 9 resistant isolates were viable. They were co-resistant to other carbapenems, ceftazidime, aztreonam, and gentamicin, and four isolates were resistant to ciprofloxacin. Impipenem resistance could not be transferred to susceptible strains. No plasmid was extracted. Each isolate produced TEM-1, AmpC, and two enzymes (pI 6.7, 6.0), which can not be inhibited by cloxacillin and clavulanic acid. Each isolate had class I intergase gene. Nine isolates were all negative for PCR of blaIMP- and blaVIM- genes, but positive for blaOXA-23 specific PCR. Sequencing found 100% homology with blaOXA-23. PFGE found 3 clones (A type: 5 isolates; B type: 3 isolates; C type: 1 isolate). Control isolates (imipenem-susceptible, but ceftazidime, ciprofloxacin, and gentamicin resistant) were also A clone.

CONCLUSIONSProduction of OXA-23 carbapenemase in A. baumannii was one of the main mechanisms of carbapenems resistance at our hospital. It brings concern that imipenem-resistant clone has evoluted from nosocomial multiple-resistant strains.

Acinetobacter baumannii ; drug effects ; genetics ; Bacterial Proteins ; metabolism ; Carbapenems ; pharmacology ; Ceftazidime ; pharmacology ; Cephalosporin Resistance ; Drug Resistance, Microbial ; Drug Resistance, Multiple, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Humans ; Microbial Sensitivity Tests ; Sequence Analysis, DNA ; beta-Lactamases ; metabolism

BACKGROUNDS/AIMS: Recently, treatment failure with the third generation of cephalosporin was increasingly noted in patients with spontaneous bacterial peritonitis (SBP). We therefore were to evaluate the pattern of antibiotic resistance and its clinical significance. METHODS: We retrospectively analyzed 580 episodes of SBP occurring between 1995 and 1999. There were 87 episodes of SBP in 1995, 222 in 1998, and 271 in 1999. The pattern of isolated organisms and antibiotic resistance, and prognostic factors for survival, were analyzed. RESULTS: Microorganisms were isolated in 41% of total episodes. The three most frequently isolated organisms were E. coli (48%), K. pneumoniae (15%), and Aeromonas (8%). The percentage of resistant strains to cefotaxime (9%, 14%, 32%) and ciprofloxacin (13%, 21%, 32%) significantly increased. The proportion of E. coli producing extended spectrum beta-lactamase (ESBL) also increased significantly (0%, 16%, 33%). The need of secondary antibiotics such as imipenem due to treatment failure was significantly increased from 0% in 1995 to 33% in 1999. Overall in-hospital mortality, however, was not changed (20%, 20%, 24%, respectively). The factor affecting early mortality was renal failure at diagnosis. Prognostic factors for long-term survival were the presence of associated malignancy and ESBL-producing microorganisms. CONCLUSION: Microorgansims resistant to third generation cephalosporin and quinolone were increasingly isolated over the 5 years in patients with SBP. Measures to prevent in-hospital spread of resistant strains and indiscreet use of antibiotics should therefore be instituted.
4-Quinolones ; Adult ; Aged ; Anti-Infective Agents/pharmacology ; Bacterial Infections/complications/*drug therapy/*microbiology/mortality ; Cephalosporin Resistance ; Drug Resistance ; English Abstract ; Female ; Human ; Liver Cirrhosis/complications ; Male ; Middle Aged ; Peritonitis/complications/*drug therapy/microbiology/mortality ; Prognosis ; Retrospective Studies ; Survival Rate

BACKGROUND: Necrotizing fasciitis is a life threatening severe soft tissue infection primarily involving the fascia and the subcutaneous tissue with thrombosis of the cutaneous microcirculation. The purpose of the study was to analyze the microbiological and clinical characteristics of necrotizing fasciitis in Korea and to suggest adequate antibiotic therapy. METHODS: We retrospectively reviewed medical records of three Soonchunhyang University Hospitals in Seoul, Bucheon and Cheonan. Patients admitted for skin graft or secondary treatment were excluded. Blood cultures were obtained at the time of admission and pus cultures were obtained at the time of first operative debridement. RESULTS: Twenty two patients (16 males, 6 females, 16~82 years old, median age: 59 years old) were enrolled for this study. Fourteen pateints underwent surgical treatment and 2 of them died of necrotizing fasciitis. Gram positive organisms were isolated in 13 cases and gram negative organisms were isolated in 11 cases. Third generation cephalosporin resistant gram negative organisms were isolated in 3 cases. CONCLUSIONS: This study suggest that characteristics of necrotizing fascitis in Korea were; high proportion of aged person, predominance of type 2 necrotizing fascitis and increasing tendency of third generation cephalosporin resistant gram negative bacterial infections. Consequently, initial choice of empirical antibiotics for necrotizing fasciitis should consider 3rd generation cephalosporin resistant gram negative organisms. Prompt surgical debridement and adequate antimicrobial therapy are mandatory for improved survival.
Anti-Bacterial Agents ; Cephalosporin Resistance ; Chungcheongnam-do ; Debridement ; Fascia ; Fasciitis, Necrotizing* ; Female ; Gram-Negative Bacterial Infections ; Gyeonggi-do ; Hospitals, University* ; Humans ; Korea* ; Male ; Medical Records ; Microcirculation ; Retrospective Studies ; Seoul ; Skin ; Soft Tissue Infections ; Subcutaneous Tissue ; Suppuration ; Thrombosis ; Transplants

Salmonella enterica serovar Typhimurium is one of the most important bacterial pathogens causing diarrhea. The resistance of S. typhimurium to antimicrobial agents, which has recently been isolated from patients, is causing serious problems. We investigated the effects of salicylic acid (Sal) and acetyl salicylate (AcSal) on the susceptibility of S. typhimurium to cephalosporin antibiotics, which are known to increase resistance to cephalosporin and quinolone antibiotics. The MIC of cephalosporin antibiotics was higher than that of the media without Sal. The rate of accumulation of ethidium bromide (EtBr) in the bacteria by the outer membrane protein (Omp) was not different from that of the bacteria cultured in the medium containing Sal. However, Carbonyl cyanide-m-chlorophenylhydrazone (CCCP), an inhibitor of bacterial efflux pumps, significantly reduced the rate of accumulation of EtBr in bacteria cultured on Sal containing medium. In the medium containing CCCP, the MIC of the antimicrobial agent tended to decrease as compared with the control. In addition, the MIC of the bacteria treated with CCCP and Sal was higher than that of the antimicrobial agent against the CCCP treated experimental bacteria. These results suggest that Sal decreases the expression of OmpF in the Omp of S. typhimurium and reduces the permeability of cephalosporin antibiotics to bacteria, which may induce tolerance to cephalosporin antibiotics.
Anti-Bacterial Agents ; Anti-Infective Agents ; Bacteria ; Carbonyl Cyanide m-Chlorophenyl Hydrazone ; Cephalosporin Resistance ; Cephalosporins ; Diarrhea ; Ethidium ; Humans ; Membrane Proteins ; Permeability ; Salicylic Acid ; Salmonella enterica ; Salmonella typhimurium ; Salmonella ; Serogroup