BACKGROUND/AIMS: The inhibitory effects of the combination of beta-lactam with ciprofloxacin or amikacin against clinical isolates of multidrug-resistant Pseudomonas aeruginosa were evaluated. METHODS: This study examined ten isolates with variable levels of resistance to ceftazidime, cefepime, piperacillin/tazobactam, meropenem, ciprofloxacin, and amikacin. The efficacy of the combined antibiotics was studied using a checkerboard method or in vitro killing assay. RESULTS: The combination of ceftazidime, cefepime, aztreonam, piperacillin-tazobactam, or meropenem with amikacin showed synergistic effects for all of the strains regardless of the minimum inhibitory concentration (MIC) of amikacin, but combination with ciprofloxacin showed a synergistic effect for the isolate with a low MIC of ciprofloxacin by the checkerboard method. The isolates with a high MIC of ciprofloxacin showed an indifferent effect in combination with beta-lactam and ciprofloxacin. The in vitro killing assay showed that meropenem with ciprofloxacin acted synergistically for the isolates with a MIC of 16 microgram/mL of ciprofloxacin. However, amikacin showed synergistic effects with meropenem for the isolates with high-level resistance against amikacin, i.e., up to an MIC of 128 microgram/mL. Contrary to the checkerboard method results, no synergy was observed for the combination of ceftazidime/piperacillin-tazobactam and amikacin. CONCLUSIONS: Meropenem with amikacin can be the first choice for infections caused by multidrug-resistant P. aeruginosa when the level of resistance is not known.
Amikacin ; Anti-Bacterial Agents ; Aztreonam ; Ceftazidime ; Cephalosporins ; Ciprofloxacin ; Homicide ; Microbial Sensitivity Tests ; Pseudomonas ; Pseudomonas aeruginosa ; Thienamycins

Clinical isolates of Acinetobacter spp. in Korea exhibit higher antimicrobial resistance rates than in foreign countries and frequently show multi-drug resistance. Approximately 67% (272/405) of Acinetobacter baumannii isolates collected from 19 hospitals in Korea in 2008 exhibited intermediate susceptibility or resistance to imipenem and/or meropenem. The most important mechanisms in acquiring carbapenem resistance in A. baumannii in Korea are production of OXA-23 and overproduction of OXA-51, while that in non-baumannii Acinetobacter is the production of metallo-beta-lactamases. All the carbapenem-resistant A. baumannii isolates were identified as clonal complex 92 and belonged to worldwide clone 2.
Acinetobacter ; Acinetobacter baumannii ; Clone Cells ; Drug Resistance, Multiple ; Imipenem ; Korea ; Thienamycins

BACKGROUND: The MicroScan MICroSTREP plus panel for susceptibility testing of various streptococci, including Streptococcus pneumoniae, has recently been introduced in Korea. The current study evaluated the usefulness of MicroScan MICroSTREP plus panel for antimicrobial susceptibility test of S. pneumoniae. METHODS: A total of 75 clinical isolates of S. pneumoniae were tested for antimicrobial susceptibility to penicillin, cefotaxime, ceftriaxone, meropenem, vancomycin, clindamycin, erythromycin, and levofloxacin with the MicroScan MICroSTREP plus panel and clinical and laboratory standard institute (CLSI) reference broth microdilution method. For 46 of 75 isolates, additional susceptibility tests to penicillin and cefotaxime were performed with Etest. RESULTS: The overall essential agreement of MICs (within one dilution of MICs) defined by the MicroScan MICroSTREP plus panel and reference method was 93.0%. Overall there were 11.7% minor, 0.7% major, and 0.7% very major interpretative category errors observed. The results of antibiotic susceptibility testing by Etest were similar to those obtained by the MicroScan MICroSTREP plus panel. CONCLUSION: The MicroScan MICroSTREP plus panel, a commercial broth microdilution method, has a comparable accuracy to CLSI broth microdilution method for the resistance testing of S. pneumonia. This panel can be used for determining susceptibilities of S. pneumoniae to a wide variety of antimicrobial agents in clinical microbiology laboratories.
Anti-Infective Agents ; Cefotaxime ; Ceftriaxone ; Clindamycin ; Erythromycin ; Korea ; Ofloxacin ; Penicillins ; Pneumonia ; Streptococcus ; Streptococcus pneumoniae ; Thienamycins ; Vancomycin

OBJECTIVETo study the in vitro antibacterial activity of meropenem combined with doxycycline, ciprofloxacin, sulbactam or cefoperazone/sulbactam against clinically isolated extensively drug-resistant Acinetobacter baumannii (XDRAB).

METHODSUsing a checker board synergy design, the minimal inhibitory concentration (MIC) of antibiotics against 50 isolates of XDRAB was determined by broth microdilution antifungal susceptibility test. The fractional inhibitory concentration (FIC) index was calculated to determine the combined effect of the antibiotics.

RESULTSMeropenem showed significantly reduced MIC50 and enhanced antimicrobial activities when combined with doxycycline, sulbactam or cefoperazone/sulbactam. The FIC results suggested that the main actions of doxycycline, sulbactam, and cefoperazone/sulbactam were synergistic (38%, 26%, and 10%, respectively) and addictive (62%, 74%, and 90%, respectively) without indifferent or antagonistic effects. The main actions of meropenem combined with ciprofloxacin were additive (56%) and indifference (44%) with synergistic and antagonistic effects.

CONCLUSIONMeropenem combined with doxycycline, sulbactam or cefoperazone/sulbactam shows excellent activity against clinical isolates of XDRAB.

BACKGROUND: The recently issued Korean version of antimicrobial susceptibility cards for Vitek 2 system uses an adjusted antimicrobial combination that reflects Korean clinical practice and CLSI guidelines. We evaluated the two Korean antimicrobial susceptibility testing cards for gram negative rods, AST N056 and AST N055. METHODS: The results of susceptibility tests were compared between the original and Korean cards. A number of the same antimicrobials included in the both cards were 15 in AST N041-AST N056 and 17 in AST N022-AST N055. Susceptibilities to the newly added antimicrobials, aztreonam, tobramycin, and meropenem for AST N056; and cefotaxime, levofloxacin, and minocycline for AST N055 were compared with those obtained by disc diffusion test and, in case of discrepancy, by confirmative Etest or broth dilution method. RESULTS: In comparison between AST N041 and AST N056 cards, the average discrepancy rate per strain was 0.34, minor error was 88.2%, and major error and very major error were both 5.9%. In comparison between AST N022 and AST055 cards, the average discrepancy rate per strain and very major error were 1.23 and 4.4%, respectively. The three antimicrobial agents added into AST N055 card showed highly discrepant results as a total of 49 items (44.1%) in 111 isolates were discrepant with very major error of 5.9% and major error of 2.0%. CONCLUSION: AST N056 showed acceptable results in most items including the newly added antimicrobial agents. However, in the case of AST N055 card that showed a relatively high discrepancy, other indicator antibiotics should be referred to for newly added three antimicrobials. For the antibiotics that showed a high discrepancy between the original and Korean cards, a comparison study should be performed using the standard method and clinical isolates collected in Korea.
Anti-Bacterial Agents ; Anti-Infective Agents ; Aztreonam ; Cefotaxime ; Diffusion ; Enterobacteriaceae ; Korea ; Minocycline ; Ofloxacin ; Sprains and Strains ; Thienamycins ; Tobramycin

This article presents the case of a bilateral chronic subdural hematoma which was contaminated with Klebsiella pneumoniae and resulted in a life-threatening central nervous system infection. After repeated of bilateral burr-hole drainage, the patient became hyperpyrexic and drowsy. Suppuration within the subdural space was suspected and then the patient underwent bilateral fronto-temporo-parietal craniotomies, and pus was evacuated. Its cultures revealed Klebsiella pneumoniae. Intravenous meropenem was given for 6 weeks. He recovered completely. Microorganisms like Klebsiella pneumoniae may directly infect the subdural space with iatrogenic contamination.
Central Nervous System Infections ; Craniotomy ; Drainage ; Empyema, Subdural ; Hematoma, Subdural, Chronic ; Humans ; Klebsiella ; Klebsiella pneumoniae ; Subdural Space ; Suppuration ; Thienamycins

Hafnia alvei is a Gram-negative rod that is rarely isolated from human specimens and is rarely pathogenic. It has been associated with gastroenteritis, pneumonia, urinary tract infection, bacteremia, and nosocomial wound infection, but extra-intestinal H. alvei infection is very rare. We present a case of biliary sepsis caused by H. alvei. A 42-year-old woman was admitted with abdominal pain and jaundice. She was diagnosed with metastatic cholangiocarcinoma and received conservative treatment. Six days later, hyperbilirubinemia and signs of sepsis developed and H. alvei was isolated from both the bile and blood. Despite treatment with antibiotics the organism was sensitive to (it was documented as susceptible to piperacillin/tazobactam and ciprofloxacin in sensitivity tests), the patient's condition grew worse. The antibiotics were switched to meropenem and the biliary sepsis was resolved.
Abdominal Pain ; Adult ; Anti-Bacterial Agents ; Bacteremia ; Bile ; Cholangiocarcinoma ; Ciprofloxacin ; Female ; Gastroenteritis ; Hafnia ; Hafnia alvei ; Humans ; Hyperbilirubinemia ; Jaundice ; Pneumonia ; Sepsis ; Thienamycins ; Urinary Tract Infections ; Wound Infection

PURPOSE: This study was designed to evaluate the bacteriological characteristics and antibiotics sensitivity in acute appendicitis. METHODS: The microbiologic culture and antibiotics sensitivity tests were done on 165 patients who underwent laparoscopic appendectomy under the diagnosis of acute appendicitis. The postoperative complications were also checked. The microbiologic and clinical results were compared between perforated and non-perforated groups. RESULTS: The most common organism cultured from the periappendiceal fluid was Escherichia coli (51.2%), followed by Enterobacter (16.2%) and Pseudomonas (8.9%). In the antibiotics sensitivity test, ciprofloxacin and levofloxacin were highly susceptible. Ceftriaxone and cefotaxime were also highly susceptible. Piperacillin/tazobactam, imipenem and meropenem were very highly susceptible. The complication rate of perforated appendicitis group (17.9%) was higher than that of the non-perforated appendicitis group (7.1%) (P<0.001). A surgical drain was used more frequently in perforated group (23% vs 84.6%, P<0.001). The mean in-patient days were longer in the perforated group (5.7 vs 7.2 days, P<0.001). In the patients with infectious wound complication, antibiotic resistance was more prominent in the non-perforated group than in the perforated group. CONCLUSION: In the perforated appendicitis group, more precise and careful procedure was required. In the non-perforated appendicitis group, more prudent use of the available antibiotics to conserve valuable therapeutic resources and improved infection control to limit the spread of resistant organisms was required.
Anti-Bacterial Agents ; Appendectomy ; Appendicitis ; Cefotaxime ; Ceftriaxone ; Ciprofloxacin ; Drug Resistance, Microbial ; Enterobacter ; Escherichia coli ; Humans ; Imipenem ; Infection Control ; Ofloxacin ; Postoperative Complications ; Pseudomonas ; Thienamycins

BACKGROUND: Post-transplant infections by antibiotic-resistant bacteria (ARB) are increasing in prevalence because of the wide use of broad-spectrum antibiotics. At our center, the perioperative prophylaxis for liver transplant recipients consistes of cefoperazone/sulbactam and ampicillin. When the recipient develops signs of infection, the initial antibiotics are empirically replaced with meropenem and vancomycin. We analyzed the epidemiology of ARB to assess the appropriateness of replacing empirical antibiotics during the first month after liver transplantation. METHODS: We reviewed 88 patients who had undergone living donor liver transplant between January 2006 and September 2007. RESULTS: Two hundred and seventy-six strains of bacteria were microbiologically documented in 75 liver transplant recipients. The most common bacteria was Staphylocococcus aureus (27%), followed by coagulase-negative staphylococci (CNS, 20%), Enterococcus species (18%) and Klebsiella species (7%). Our data on the resistance pattern showed that 87.8% and 71.4% of the S. aureus and CNS were resistant to methicillin, respectively; 88% of the Enterococcus species were resistant to ampicillin and 24% to vancomycin; and 62% of all enteric gram-negative bacilli (GNB) were resistant to 3rd generation cephalosporins. No strains of meropenem-resistant GNB were detected. Only one glucose non-fermentative GNB was resistant to all antibiotics except aminoglyco sides and colistin. CONCLUSIONS: Mainly methicillin-resistant gram- positive bacterial strains, including S. aureus and CNS, can colonize in early period after transplantation. According to the epidemiologic data on the high prevalence of antibiotic-resistant organisms, the empirical treatment regimen at our center is considered as appropriate. However, shifting down to less-broad-spectrum antibiotics after the pathogens are confirmed is essential to lowering the rate of ARB.
Ampicillin ; Anti-Bacterial Agents ; Bacteria ; Cephalosporins ; Colistin ; Colon ; Enterococcus ; Glucose ; Humans ; Klebsiella ; Liver ; Liver Transplantation ; Living Donors ; Methicillin ; Methicillin Resistance ; Prevalence ; Thienamycins ; Transplants ; Vancomycin

Metronidazole-induced encephalopathy is a very rare complication of the long standing use of metronidazole. The encephalopathy is bilateral and symmetric in nature. We report on the magnetic resonance imaging (MRI) and clinical course of metronidazole-induced encephalopathy in a 60-year-old female with a persistent anaerobic brain abscess after draining of the abscess. After 3 months of metronidazole administration, the patient complained of dysarthria, tingling sense of all extremities, and left hemiparesis. MRI revealed symmetric hyperintensity lesions in medulla, pons, dentate nuclei of cerebellum, and splenium of corpus callosum, all of which represent typical findings of metronidazole-induced encephalopathy. In addition, asymmetric lesions in midbrain, thalamus, putamen and cerebral subcortical white matter were noted. The patient recovered after discontinuation of metronidazole and the remaining abscess was successfully treated with meropenem and levofloxacine.
Abscess ; Brain ; Brain Abscess ; Brain Diseases, Metabolic ; Cerebellum ; Corpus Callosum ; Dysarthria ; Extremities ; Female ; Humans ; Magnetic Resonance Imaging ; Mesencephalon ; Metronidazole ; Middle Aged ; Ofloxacin ; Paresis ; Pons ; Putamen ; Thalamus ; Thienamycins