No abstract available.
Aged ; Drug Resistance, Bacterial ; Humans ; Imipenem/pharmacology/therapeutic use ; Klebsiella Infections/diagnosis/drug therapy/*microbiology ; Klebsiella pneumoniae/drug effects/isolation & purification/*physiology ; Male ; Microbial Sensitivity Tests ; Phenotype ; Sepsis/diagnosis/drug therapy/*microbiology ; Thienamycins/pharmacology/therapeutic use

OBJECTIVETo study the drug resistance of Acinetobacter baumannii (AB) producing VIM-2-type metallo-β-lactamase (MBL) isolated from burn patients of our ward against carbapenem antibiotics and its homology.

METHODSA total of 400 strains of AB (identified) were isolated from sputum, urine, blood, pus, and wound drainage. of burn patients hospitalized in our ward from September 2011 to March 2014. Drug resistance of the 400 strains of AB to 15 antibiotics, including compound sulfamothoxazole, aztreonam, etc. , was tested using the automatic microorganism identifying and drug sensitivity analyzer. Among the carbapenems-resistant AB isolates, modified Hodge test was applied to screen carbapenemase-producing strains. The carbapenemase genes of the carbapenemase-producing strains, and the mobile genetic elements class I-integron (Intl1) gene and conserved sequence (CS) of carbapenemase-producing strains carrying blaVIM-2 gene were determined with PCR and DNA sequencing. For carbapenemase-producing strains carrying blaVIM-2 gene, synergism test with imipenem-ethylene diamine tetraacetic acid (EDTA) and enhancement test with imipenem-EDTA and ceftazidime-EDTA were used to verify the MBL-producing status. Drug resistance of the VIM-2-type MBL-producing AB strains was analyzed. For VIM-2-type MBL-producing AB strains, plasmid conjugation experiment was used to explore the transfer of plasmid; outer membrane protein (OMP) CarO gene was detected by PCR. For VIM-2-type MBL-producing AB strains carrying CarO gene, the protein content of CarO was analyzed with sodium dodecyl sulfate polyacrylamide gel electro- phoresis. The repetitive consensus sequence of Enterobacteriaceae genome PCR (ERIC-PCR) was carried out for gene typing of VIM-2-type MBL-producing AB strains to analyze their homology.

RESULTS(1) The resistant rates of the 400 strains of AB against levofloxacin and compound sulfamethoxazole were low. A total of 381 carbapenems-resistant AB strains were screened, including 240 carbepenemase-producing strains. (2) Out of the 240 carbepenemase-producing strains, 18 strains were found to harbor the blaVIM-2 gene, accounting for 7.5%; 133 strains carried the blaTEM-1 gene, accounting for 55.42%; 195 strains carried the blaOXA23 gene, accounting for 81.25%; 188 strains carried the bla(armA) gene, accounting for 78.33%. (3) Eighteen carbepenemase-producing strains which carried the bla(VIM-2) gene were found to carry the Intl1 gene, showing the Intl1-VIM linkage. Simultaneously, Intl1 variable area CS showed diversity. (4) Eighteen carbepenemase-producing strains which carried the blaVIM-2 gene were verified to produce MBL. The resistant rates of the 18 strains of AB against compound sulfamethoxazole were the lowest, followed by levofloxacin and cefoperazone/sulbactam, and those against the other antibiotics were above 60.00%. (5) Through multiple joint tests, plasmid conjugation experiment positive transfer strain was not found in 18 VIM-2-type MBL-producing AB strains. (6) Nine out of the 18 VIM-2-type MBL-producing AB strains were found to carry CarO gene. The OMP CarO of VIM-2-type MBL-producing AB strains carrying CarO gene was lost or lowered in the protein content. (7) The 18 VIM-2-type MBL-producing AB strains were classified into 6 genotypes by the ERIC-PCR. There were respectively 6, 4, 3, and 1 stain (s) in genotypes A, B, C, and F, and there were 2 strains in genotypes D and E respectively.

CONCLUSIONSThe resistance mechanism of AB against carbapenems is mainly mediated by blaTEM-1, blaOXA-23, and bla(arma); meanwhile, VIM-2-type MBL-producing and lack or change in OMP CarO are attributable to carbapenems resistance of clinically isolated AB from burn wards, and the Intl1 gene may take a part in blaVIM-2 gene transmission.

Acinetobacter baumannii ; drug effects ; enzymology ; genetics ; isolation & purification ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Bacterial Proteins ; Burns ; drug therapy ; microbiology ; Carbapenems ; pharmacology ; Drug Resistance, Bacterial ; Genes, Bacterial ; Humans ; Imipenem ; pharmacology ; Microbial Sensitivity Tests ; Sulbactam ; pharmacology ; beta-Lactamases ; genetics

The aim of this study was to determine the risk factors for nosocomial infections of imipenem-resistant Pseudomonas aeruginosa (IRPA). A prospective case-control study was performed at a tertiary care hospital in Ankara from January to December 2004. The patients with nosocomial P. aeruginosa infection were included in the study. The features of the patients with IRPA infections were compared to those with imipenem-sensitive P. aeruginosa (ISPA) infections. Only the first isolation of P. aeruginosa was considered. Nosocomial infections were defined according to Center for Disease Control (CDC) criteria. IRPA was isolated from 75 (44.1%) patients, and ISPA was isolated from 95 (55.9%) patients during the study period. IRPA were most frequently isolated from endotracheal aspirate (19%) cultures (p= 0.048), whereas ISPA were most frequently isolated from urine (28%) cultures (p= 0.023). In multivariate analysis, a longer duration of hospital stay until P. aeruginosa isolation (odds ratio [OR], 1.027; 95% confidence interval [CI], 1.002-1.054, p=0.034), arterial catheter administration (OR, 2.508; 95% CI, 1.062-5.920, p=0.036), vancomycin (OR, 2.882; 95% CI, 1.130-7.349, p=0.027), piperacillin-tazobactam (OR, 6.425; 95% CI, 2.187-18.875, p=0.001), and imipenem (OR, 3.580; 95% CI, 1.252- 10.245, p=0.017) treatment within the 14 days before isolation of IRPA were independently associated with imipenem resistance. It was concluded that treatment with imipenem, vancomycin and piperacillin-tazobactam were major risk factors for IRPA infections in hospitalized patients. The nosocomial occurrence of IRPA was also strongly related to the duration of hospital stay, arterial catheter administration.
Adult ; Aged ; Anti-Bacterial Agents/*pharmacology/therapeutic use ; Case-Control Studies ; Cross Infection/drug therapy/epidemiology/*microbiology ; Drug Resistance, Multiple, Bacterial ; Female ; Humans ; Imipenem/*pharmacology/therapeutic use ; Length of Stay ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Multivariate Analysis ; Penicillanic Acid/analogs & derivatives/pharmacology/therapeutic use ; Piperacillin/pharmacology/therapeutic use ; Prospective Studies ; Pseudomonas Infections/drug therapy/epidemiology/*microbiology ; Pseudomonas aeruginosa/drug effects/*isolation & purification ; Risk Factors ; Vancomycin/pharmacology/therapeutic use

No abstract available.
Aged ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Cefotaxime/therapeutic use ; China ; Ciprofloxacin/therapeutic use ; Citrobacter freundii/drug effects/*enzymology/isolation & purification ; Drug Resistance, Multiple, Bacterial ; Humans ; Imipenem/pharmacology ; Male ; Microbial Sensitivity Tests ; Respiratory Tract Infections/*diagnosis/drug therapy/microbiology ; Thienamycins/pharmacology ; beta-Lactamases/*metabolism

No abstract available.
Aged ; Anti-Bacterial Agents/pharmacology/therapeutic use ; Asian Continental Ancestry Group ; Bacterial Proteins/genetics/*metabolism ; China ; Cilastatin/therapeutic use ; Citrobacter freundii/drug effects/*enzymology/isolation & purification ; Drug Combinations ; Drug Resistance, Multiple, Bacterial ; Humans ; Imipenem/therapeutic use ; Male ; Microbial Sensitivity Tests ; Plasmids/*metabolism ; Respiratory Tract Infections/*diagnosis/drug therapy/microbiology ; beta-Lactamases/genetics/*metabolism

OBJECTIVETo determine the risk factors and outcomes of imipenem-resistant Acinetobacter baumannii (IRAB) bloodstream infection (BSI) cases, since there is very little publication on Acinetobacter baumannii infections from Malaysia.

METHODSA cross sectional study of 41 cases (73.2%) of imipenem-sensitive Acinetobacter baumanii (ISAB) and 15 cases (26.8%) of IRAB was conducted in a teaching hospital which was located at North-Eastern state of Malaysia.

RESULTSThere was no independent risk factor for IRAB BSI identified but IRAB BSI was significantly associated with longer bacteraemic days [OR 1.23 (95% CI 1.01, 1.50)]. Although prior use of carbepenems and cephalosporin were higher among IRAB than ISAB group, statistically they were not significant. There was no significant difference in term of outcomes between the two groups.

CONCLUSIONSAlthough statistically not significant, this analysis compliments previous publication highlighting the importance of appropriate empiric antibiotic usage in hospital especially carbepenems and need further evaluation with bigger subjects.

Acinetobacter Infections ; drug therapy ; epidemiology ; microbiology ; Acinetobacter baumannii ; drug effects ; isolation & purification ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Bacteremia ; drug therapy ; epidemiology ; microbiology ; Case-Control Studies ; Cross-Sectional Studies ; Female ; Hospitals, Teaching ; Humans ; Imipenem ; pharmacology ; therapeutic use ; Malaysia ; epidemiology ; Male ; Middle Aged ; Risk Factors ; Treatment Outcome ; Young Adult ; beta-Lactam Resistance