OBJECTIVETo investigate the epidemiological status of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) and the drug resistance profiles of such organisms.

METHODSA total of 282 clinical isolates of E. coli and 180 of K. pneumoniae were collected from different districts of Zhejiang Province. Inhibitor potentiated broth dilution tests were performed for detecting extended-spectrum beta-lactamases. Etests were performed to detect the drug resistance of these strains against nine commonly used antibiotics.

RESULTSThe prevalence of extended-spectrum beta-lactamases in E. coli and K. pneumoniae was 34.0% and 38.3%, respectively. The average prevalence of extended-spectrum beta-lactamases in E. coli and K. pneumoniae was 35.7%. The resistance prevalence of extended spectrum beta-lactamase producing strains to ceftazidime and cefotaxime was 40% and 26% respectively, so were those to cefepime, cefoxitin, piperacillin-tazobactam, cefoperazone-sulbactam, amikacin and ciprofloxacin. All these strains were sensitive to imipenem.

CONCLUSIONThe results in this study showed that the prevalence of extended-spectrum beta-lactamases was high, while extended-spectrum beta-lactamase producing strains were resistant to most antimicrobial agents except imipenem.

Drug Resistance, Bacterial ; Escherichia coli ; drug effects ; enzymology ; Humans ; Klebsiella pneumoniae ; drug effects ; enzymology ; Microbial Sensitivity Tests ; beta-Lactamases ; biosynthesis

OBJECTIVETo investigate how acetamiprid, a new insecticide, affects the activity of superoxide dismutase (SOD), catalase (CAT), and ATPase and the SOD isozyme patterns in two G bacteria, E. coli K12 and Pse.FH2, and one G+ bacterum, B. subtilis.

METHODSThe SOD, CAT, and ATPase specific activities of cell lysates were determined spectrophotometrically at 550 nm, 240 nm, and 660 nm, respectively, with kits A001, A016, and A007. SOD isozyme patterns were detected by native PAGE analysis.

RESULTSSOD and CAT activities in the tested bacteria increased significantly in a concentration-dependent manner after different concentrations of acetamiprid were applied. The activity of SOD in B. subtilis and Pse.FH2 was stimulated and reached the highest level after treatment with 100 mg/L acetamiprid for 0.5 h. For Pse.FH2, there was another stimulation of SOD activity after acetamiprid application for about 8.0 h and the second stimulation was stronger than the first. The stimulation by acetamiprid showed a relative lag for E. coli K12. Acetamiprid seemed to exhibit a similar effect on CAT activity of the two G bacteria and had an evident influence on ATPase activity in the three bacteria within a relatively short period. Only one SOD isozyme was detectable in Pse.FH2 and B. subtilis, while different isozyme compositions in E. coli could be detected by native PAGE analysis.

CONCLUSIONAcetamiprid causes a certain oxidative stress on the three bacteria which may not only elevate SOD and CAT activities but also generate new SOD isozymes to antagonize oxidative stress. However, this oxidative stress lasts for a relatively short time and does not cause a long-term damage.

Adenosine Triphosphatases ; metabolism ; Bacillus ; drug effects ; enzymology ; Bacteria ; drug effects ; enzymology ; Catalase ; metabolism ; Escherichia coli ; drug effects ; enzymology ; Insecticides ; pharmacology ; Isoenzymes ; metabolism ; Neonicotinoids ; Pseudomonas ; drug effects ; enzymology ; Pyridines ; pharmacology ; Superoxide Dismutase ; metabolism

OBJECTIVETo investigate the possible differences in antimicrobial resistance of Escherichia coli isolated from different samples in children.

METHODSSix hundred and twenty-nine samples from urine, sputum, blood and secretion were collected from June 2004 to May 2009 for bacterial identification by VITEK-32 automatic system and antimicrobial susceptibility tests by Kirby-Bauer method. The drug resistance rate of Escherichia coli isolated from different samples was compared.

RESULTSTwo hundred and sixty strains of Escherichia coli were isolated , and 108 of which were from urine , 64 from sputum, 54 from secretion and 23 from blood. ESBLs were detected in 96 (36.9%) of the 260 isolates, AmpC enzymes in 32 (12.3%), and ESBLs+AmpC in 8 (3.1%). The ESBLs positive rate of Escherichia coli isolates from sputum was significantly higher than that from other samples (P<0.05). The antimicrobial resistance rate of Escherichia coli strains from different samples to amoxicillin/clavulanic acid, ticarcillin/clavulanic acid, piperacillin, cefotaxime, cefuroxime, cefepime, gentamicin, cotrimoxazole, and nitrofurantoin was different. The resistance rate of the strains from sputum samples was higher than that from the other samples (P<0.05).

CONCLUSIONSEscherichia coli isolated from different samples have different antimicrobial resistance rates in children, so the selection of antibiotics for infections confirmed by bacterial cultures from different samples should based on drug sensitivity results.

Adolescent ; Child ; Child, Preschool ; Drug Resistance, Bacterial ; Escherichia coli ; drug effects ; enzymology ; isolation & purification ; Female ; Humans ; Male ; beta-Lactamases ; analysis

PURPOSE: Extended spectrum beta-lactamases (ESBLs) are cephalosporinases that confer resistance to a wide variety of oxyimino cephalosporins and create serious therapeutic problems. In addition, the quinolone resistance qnr genes are becoming increasingly prevalent in clinical isolates, some of which also produce ESBL. This study was designed to evaluate the occurrence and genotypic distribution of ESBL producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) as well as the prevalence and distribution of qnr genes in ESBL-producing isolates in a tertiary care hospital in Korea. MATERIALS AND METHODS: We tested a total of 111 ESBL-producing isolates of E. coli and K. pneumoniae, which were collected at Kyung Hee Medical Center from November 2006 to June 2008. ESBL production was determined by the Clinical and Laboratory Standards Institute (CLSI) ESBL confirmatory test. The cefotaxime and ceftazidime resistance of the ESBL-producers were transferred to azide-resistant E. coli J53 by conjugation. The presence and identity of ESBL and qnr genes were determined by polymerase chain reaction (PCR) and nucleotide sequencing. RESULTS: The prevalence of ESBLs was 17.7% (297/1,680) of E. coli and 26.5% (240/904) of K. pneumoniae in our hospital during the study periods. Of the 111 collected isolates, 69 isolates were E. coli and 42 isolates were K. pneumoniae. The most prevalent ESBL genotype was CTX-M15. Among the ESBL-producing isolates, 4 E. coli (5.8%) and 17 K. pneumoniae (40.5%) contained qnr genes. qnrB4 was the most frequent type in both E. coli and K. pneumoniae. CONCLUSION: CTX-M15 was the most frequently encountered ESBL. In addition, a high prevalence of qnr genes among ESBL-producing K. pneumoniae was identified in this study.
Azides/pharmacology ; Bacterial Proteins/*metabolism ; Cefotaxime/pharmacology ; Ceftazidime/pharmacology ; Drug Resistance, Multiple, Bacterial/genetics ; Escherichia coli/drug effects/*enzymology ; Escherichia coli Infections/*microbiology ; Escherichia coli Proteins/*metabolism ; Humans ; Klebsiella Infections/*microbiology ; Klebsiella pneumoniae/drug effects/*enzymology ; Korea ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; beta-Lactamases/*metabolism

The use of intrauterine devices (IUDs) have been widespread since the 1960s. In 2002, the World Health Organization estimated that approximately 160 million women worldwide use IUDs. However, IUDs are associated with short-term complications such as vaginal bleeding, pelvic discomfort, dyspareunia and pelvic infection. Herein, we report the case of a woman who had recurrent urinary tract infection (UTI) due to the use of an IUD, even after treatment. The patient developed four episodes of UTI within a seven-month period after IUD insertion. During each episode of UTI, extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) was cultured from the patient’s midstream urine. The IUD was finally removed, and culture of the removed IUD was positive for ESBL-producing E. coli. An infected IUD as a source of recurrent UTI should be considered in women with IUD in situ who develop recurrent UTI even after treatment.
Adult ; Anti-Bacterial Agents ; therapeutic use ; Escherichia coli Infections ; drug therapy ; etiology ; Female ; Humans ; Intrauterine Devices ; adverse effects ; Microbial Sensitivity Tests ; Recurrence ; Treatment Outcome ; Urinary Tract Infections ; drug therapy ; etiology ; microbiology ; Uropathogenic Escherichia coli ; enzymology ; beta-Lactamases ; metabolism

The aims of this study were to prepare Cu(2+)-loaded montmorillonite (Cu-MMT) and investigate its bactericidal activity and mechanism. Cu-MMT was prepared by the method of ion exchange reaction. The structure and surface characteristic of Cu-MMT were determined. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Cu-MMT against the strain of Escherichia coli were determined. The activities of intracellular enzyme in bacterial solution were measured, and the morphology of E. coli was observed during the interaction between Cu-MMT and bacteria. The results showed that treatment with Cu2+ increased cation exchange capacity of montmorillonite, but specific surface area and surface negative charge density were decreased. The MIC and MBC of Cu-MMT against the tested E. coli were 0.16 and 0.64 mg x m(L(-1), respectively. Cu-MMT could destroy bacterial cellular membrane and then resulted in leakage of intracellular enzymes such as asparate aminotransferase, lactate dehydrogenase and alanine aminotransferase. These suggest that Cu-MMT has a strong bactericidal activity. The bactericidal mechanism of Cu-MMT may be that bacteria are adsorbed by Cu-MMT, and then morphology and permeability of cellular membrane are changed. This leads to an efflux of intracellular contents and the death of bacteria.
Alanine Transaminase ; metabolism ; Anti-Bacterial Agents ; chemistry ; pharmacology ; Aspartate Aminotransferases ; metabolism ; Bentonite ; chemistry ; pharmacology ; Copper ; chemistry ; pharmacology ; Drug Compounding ; Escherichia coli ; drug effects ; enzymology ; Escherichia coli Proteins ; metabolism ; L-Lactate Dehydrogenase ; metabolism ; Microbial Sensitivity Tests

BACKGROUNDThe rise of the production of CTX-M class extended spectrum β-lactamases (ESBLs) has been well documented in traveling countries but no data are found for Macao, an international travel city. The objectives of this study were to identify the antimicrobial resistance pattern, and determine the prevalence, genotype and clonal relationship of ESBLs in 209 clinical Escherichia coli strains from Macao, China.

METHODSAntimicrobial susceptibility test was performed to determine the resistance patterns of the isolates using the disk diffusion method with 17 antimicrobial agents. Phenotypic detection was screened and confirmed according to the Clinical and Laboratory Standards Institute. Genotypic characterization was detected by isoelectric focusing analysis, polymerase chain reaction and sequencing. The clonal relationship between the different ESBL isolates was studied by pulsed-field gel electrophoresis (PFGE).

RESULTSImipenem and meropenem exhibited 100% susceptible among 209 strains. Overall, 82.3%, 67.3%, 52.9%, 51.2% and 51.0% of the isolates displayed resistance to ampicillin, tetracycline, ciprofloxacin, sulfamethoxazole trimethoprim and gentamycin. The prevalence rate of ESBLs was 30.1%. Antibiotic resistances were found to be significantly higher among the ESBL producing group compared to non-ESBL producing group. We detected CTX-M-14 to be the major genotypic characterization of ESBLs (76.2%). Two strains showed indistinguishable patterns by PFGE.

CONCLUSIONSThe prevalence of antimicrobial resistance is alarming high in Macao. Antimicrobial resistance is significantly higher among the ESBL producing group. This study documented CTX-M-14 as the predominant ESBL type. Although indistinguishable pattern was found between two strains, it was too small to decide whether any of the investigated strains was epidemic. Our findings may be also pertinent for other geographic areas undergoing similar travel characteristics to understand the corresponding effects on bacterial populations.

Anti-Infective Agents ; pharmacology ; China ; Drug Resistance, Microbial ; genetics ; Electrophoresis, Gel, Pulsed-Field ; methods ; Escherichia coli ; drug effects ; enzymology ; genetics ; Genotype ; Isoelectric Focusing ; Macau ; beta-Lactamases ; genetics ; metabolism

OBJECTIVETo study the prevalence and drug resistance of extended-spectrum-β-lactamases (ESBLs)-producing bacteria in blood culture isolated from children with hematological malignancy after chemotherapy.

METHODSBlood samples taken from 3264 children with hematological malignancy and severe infection following chemotherapy between 2002 and 2008 were cultured using the Bact/ALTER 3D blood culture system. VITEK 60 automicroscan was used to identify viral species and to conduct drug resistance tests. The results were indentified according to National Committee for Clinical Laboratory Standard guidelines.

RESULTSFifty-eight strains of Escherichia coli and fifty-one strains of Klebsiella pneumoniae were isolated. Thirty-eight strains of Escherichia coli and nineteen strains of Klebsiella pneumoniae were ESBLs-producing and these ESBLs-producing strains were less susceptible than those that were non-ESBLs-producing to most antibiotics. Both ESBL- and non-ESBL-producing strains were susceptible to imipenem, piperacillin/tazobactam and amikacin.

CONCLUSIONSThe prevalence of ESBLs-producing bacteria is high in childrn with hematological malignancy and infection following chemotherapy. ESBLs-producing bacteria are resistant to common antibiotics, suggesting that antibiotic treatment based on the result of antimicrobial susceptibility test is necessary in these children.

Adolescent ; Bacteremia ; microbiology ; Child ; Child, Preschool ; Drug Resistance, Bacterial ; Escherichia coli ; drug effects ; enzymology ; isolation & purification ; Female ; Hematologic Neoplasms ; drug therapy ; microbiology ; Humans ; Klebsiella pneumoniae ; drug effects ; enzymology ; isolation & purification ; Male ; Microbial Sensitivity Tests ; beta-Lactamases ; biosynthesis

Base Sequence ; Conjugation, Genetic ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Escherichia coli ; drug effects ; enzymology ; Humans ; Klebsiella pneumoniae ; drug effects ; enzymology ; Microbial Sensitivity Tests ; Molecular Sequence Data ; Polymerase Chain Reaction ; Transformation, Bacterial ; beta-Lactamases ; genetics

BACKGROUND: The aim of this study was to compare the BD Phoenix (Beckton Dickinson Diagnostic Systems, USA) extended-spectrum beta-lactamase (ESBL) test with the Clinical and Laboratory Standards Institute (CLSI) ESBL phenotypic confirmatory test by disk diffusion (CLSI ESBL test) in Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca and Proteus mirabilis. METHODS: We tested 224 clinical isolates of E. coli, K. pneumoniae, K. oxytoca and P. mirabilis during May 2006 to March 2007. These isolates were examined by the Phoenix and the CLSI ESBL tests simultaneously. For the isolates showing discordant results between the two tests, boronic acid disk test was performed to differentiate AmpC beta-lactamase and ESBL. RESULTS: Among the 224 clinical isolates, 75 and 79 isolates were positive for ESBL by CLSI ESBL test and Phoenix test, respectively. Having detected 4 more isolates as ESBL-producers, Phoenix test showed a 98.2% agreement with a 100% sensitivity and 97.3% specificity compared with CLSI ESBL test. Among the four false positive isolates, three were AmpC-positive but ESBL-negative. CONCLUSIONS: The BD Phoenix ESBL test was sensitive and specific, and can be used as a rapid and reliable method to detect ESBL production in E. coli, Klebsiella species, and P. mirabilis.
Automation ; Bacterial Proteins/classification/*metabolism ; Disk Diffusion Antimicrobial Tests ; Escherichia coli/drug effects/*enzymology/isolation & purification ; Humans ; Klebsiella/*enzymology ; Klebsiella oxytoca/drug effects/enzymology/isolation & purification ; Klebsiella pneumoniae/drug effects/enzymology/isolation & purification ; *Microbial Sensitivity Tests ; Proteus mirabilis/drug effects/*enzymology/isolation & purification ; Reagent Kits, Diagnostic ; Sensitivity and Specificity ; beta-Lactamases/classification/*metabolism