OBJECTIVE: To evaluate the synergy of the Burkholderia signaling molecule cis-2-dodecenoic acid (BDSF) and fluconazole (FLU) or itraconazole (ITRA) against two azole-resistant C. albicans clinical isolates in vitro and in vivo. METHODS: Minimum inhibitory concentrations (MICs) of antibiotics against two azole-resistant C. albicans were measured by the checkerboard technique, E-test, and time-kill assay. In vivo antifungal synergy testing was performed on mice. Analysis of the relative gene expression levels of the strains was conducted by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). RESULTS: BDSF showed highly synergistic effects in combination with FLU or ITRA with a fractional inhibitory concentration index of ⪕ 0.08. BDSF was not cytotoxic to normal human foreskin fibroblast cells at concentrations of up to 300 μg/mL. The qRT-PCR results showed that the combination of BDSF and FLU/ITRA significantly inhibits the expression of the efflux pump genes CDR1 and MDR1 via suppression of the transcription factors TAC1 and MRR1, respectively, when compared with FLU or ITRA alone. No dramatic difference in the mRNA expression levels of ERG1, ERG11, and UPC2 was found, which indicates that the drug combinations do not significantly interfere with UPC2-mediated ergosterol levels. In vivo experiments revealed that combination therapy can be an effective therapeutic approach to treat candidiasis. CONCLUSION The synergistic effects of BDSF and azoles may be useful as an alternative approach to control azole-resistant Candida infections.
Antifungal Agents ; pharmacology ; Burkholderia cenocepacia ; chemistry ; Candida albicans ; drug effects ; physiology ; Candidiasis ; drug therapy ; Drug Resistance, Fungal ; Fatty Acids, Monounsaturated ; adverse effects ; Fluconazole ; pharmacology ; Humans ; Microbial Sensitivity Tests ; Triazoles ; metabolism

OBJECTIVETo characterize carbapenem (CPM)-non-susceptible Klebsiella pneumoniae (K. pneumoniae) and carbape-nemase produced by these strains isolated from Beijing Children's Hospital based on a five-year surveillance.

METHODSThe Minimal Inhibition Concentration values for 15 antibiotics were assessed using the Phonix100 compact system. PCR amplification and DNA sequencing were used to detect genes encoding carbapenemases. WHONET 5.6 was finally used for resistance analysis.

RESULTSIn total, 179 strains of CPM-non-susceptible K. pneumoniae were isolated from January, 2010 to December, 2014. The rates of non-susceptible to imipenem and meropenem were 95.0% and 95.6%, respectively. In the 179 strains, 95 (53.1%) strains carried the blaIMP gene, and IMP-4 and IMP-8 were detected in 92 (96.8%) and 3 (3.2%) IMP-producing isolates, respectively. 65 (36.3%) strains carried the blaNDM-1 gene. 6 (3.4%) strains carried the blaKPC gene, and KPC-2 were detected in 6 KPC-producing isolates. In addition, New Delhi-Metallo-1 (NDM-1) producing isolates increased from 7.1% to 63.0% in five years and IMP-4 producing isolates decreased from 75.0% to 28.3%.

CONCLUSIONHigh frequencies of multiple resistances to antibiotics were observed in the CPM-non-susceptible K. pneumoniae strains isolated from Beijing Children's Hospital. The production of IMP-4 and NDM-1 metallo-β-lactamases appears to be an important mechanism for CPM-non- susceptible in K. pneumoniae.

Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; metabolism ; Child ; China ; epidemiology ; Drug Resistance ; Gene Expression Regulation, Bacterial ; physiology ; Gene Expression Regulation, Enzymologic ; physiology ; Hospitals, Pediatric ; Humans ; Klebsiella Infections ; epidemiology ; microbiology ; Klebsiella pneumoniae ; drug effects ; enzymology ; genetics ; Microbial Sensitivity Tests ; Population Surveillance ; Time Factors ; beta-Lactamases ; genetics ; metabolism

China ; Drug Resistance, Bacterial ; Electrophoresis, Gel, Pulsed-Field ; Fast Foods ; microbiology ; Lactobacillus ; isolation & purification ; physiology ; Microbial Sensitivity Tests ; RNA, Ribosomal, 16S ; genetics ; Streptococcus ; isolation & purification ; physiology ; Yogurt ; microbiology

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

BACKGROUNDThe incidence of vancomycin-resistant enterococci (VRE) appeared to be increasing in China, but very few nosocomial outbreaks have been reported. Our hospital had experienced an outbreak of VRE since March 2008 to March 2009. The objective of this study was to analyze the molecular features of the isolates and the control measures used to eradicate a VRE outbreak in a tertiary institution in China.

METHODSWe characterized VRE isolates from 21 infected and 11 colonized inpatients from a single hospital by pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST), the analysis of Tn1546-like elements and virulence genes detection. Infection control measures, including more environmental disinfection, screening for VRE colonization, contact precautions, education and strict antibiotic restriction, were implemented to control the outbreak.

RESULTSDuring the outbreak, a total of 32 VRE strains were obtained. There were 21 strains found in Emergency Intensive Care Unit (EICU), 9 isolates from Geriatric Ward, and two from other units. All the isolates harbored the vanA gene, however, four of them exhibited the VanB phenotype. Meanwhile, MLST analysis revealed that all isolates belonged to clonal complex (CC) 17. With the infection-control measures, the epidemic was constrained in two units (EICU and Geriatric Ward). After March 2009, no further case infected with VRE was detected in the following one-year period.

CONCLUSIONThe outbreak was controlled by continuous implementation of the infection control programme, and more rigorous infection control policy is needed.

China ; Electrophoresis, Gel, Pulsed-Field ; Enterococcus faecium ; drug effects ; genetics ; pathogenicity ; Gram-Positive Bacterial Infections ; microbiology ; transmission ; Hospitals ; Humans ; Microbial Sensitivity Tests ; Multilocus Sequence Typing ; Polymerase Chain Reaction ; Vancomycin Resistance ; genetics ; physiology

Bacteria survive in nature by forming biofilms on surfaces and probably most, if not all, bacteria (and fungi) are capable of forming biofilms. A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and extracellular DNA. Bacterial biofilms are resistant to antibiotics, disinfectant chemicals and to phagocytosis and other components of the innate and adaptive inflammatory defense system of the body. It is known, for example, that persistence of staphylococcal infections related to foreign bodies is due to biofilm formation. Likewise, chronic Pseudomonas aeruginosa lung infections in cystic fibrosis patients are caused by biofilm growing mucoid strains. Gradients of nutrients and oxygen exist from the top to the bottom of biofilms and the bacterial cells located in nutrient poor areas have decreased metabolic activity and increased doubling times. These more or less dormant cells are therefore responsible for some of the tolerance to antibiotics. Biofilm growth is associated with an increased level of mutations. Bacteria in biofilms communicate by means of molecules, which activates certain genes responsible for production of virulence factors and, to some extent, biofilm structure. This phenomenon is called quorum sensing and depends upon the concentration of the quorum sensing molecules in a certain niche, which depends on the number of the bacteria. Biofilms can be prevented by antibiotic prophylaxis or early aggressive antibiotic therapy and they can be treated by chronic suppressive antibiotic therapy. Promising strategies may include the use of compounds which can dissolve the biofilm matrix and quorum sensing inhibitors, which increases biofilm susceptibility to antibiotics and phagocytosis.
Animals ; Antibiotic Prophylaxis ; Biofilms ; drug effects ; growth & development ; Chronic Disease ; Cystic Fibrosis ; microbiology ; Drug Resistance, Microbial ; physiology ; Foreign Bodies ; microbiology ; Humans ; Microbial Consortia ; drug effects ; genetics ; immunology ; Phagocytosis ; Pseudomonas Infections ; microbiology ; Pseudomonas aeruginosa ; drug effects ; genetics ; physiology ; Quorum Sensing ; drug effects ; genetics

Antimicrobial peptides (AMPs), with their extraordinary properties, such as broad-spectrum activity, rapid action and difficult development of resistance, have become promising molecules as new antibiotics. Despite their various mechanisms of action, the interaction of AMPs with the bacterial cell membrane is the key step for their mode of action. Moreover, it is generally accepted that the membrane is the primary target of most AMPs, and the interaction between AMPs and eukaryotic cell membranes (causing toxicity to host cells) limits their clinical application. Therefore, researchers are engaged in reforming or de novo designing AMPs as a 'single-edged sword' that contains high antimicrobial activity yet low cytotoxicity against eukaryotic cells. To improve the antimicrobial activity of AMPs, the relationship between the structure and function of AMPs has been rigorously pursued. In this review, we focus on the current knowledge of α-helical cationic antimicrobial peptides, one of the most common types of AMPs in nature.
Anti-Bacterial Agents ; chemistry ; pharmacology ; Anti-Infective Agents ; chemistry ; pharmacology ; Antimicrobial Cationic Peptides ; chemistry ; pharmacology ; Bacteria ; drug effects ; Circular Dichroism ; Drug Resistance, Microbial ; physiology ; Protein Structure, Secondary ; Structure-Activity Relationship

PURPOSE: Since November 2006, imipenem-resistant Acinetobacter baumannii isolates have increased in Kyung Hee University Hospital in Seoul, Korea. The purpose of this study was to determine the genetic basis and molecular epidemiology of outbreak isolates. MATERIALS AND METHODS: Forty-nine non-repetitive isolates of the 734 IRAB strains were investigated in order to determine their characteristics. The modified Hodge and the ethylenediaminetetraacetic acid (EDTA)-disk synergy test were performed for the screening of carbapenemase and metallo-beta-lactamase production. Multiplex polymerase chain reaction (PCR) assays were performed for the detection of genes encoding for OXA-23-like, OXA-24-like, OXA-58-like and OXA-51-like carbapenemase. Pulsed-field gel electrophoresis (PFGE) was performed for strain identification. RESULTS: All isolates showed 100% resistance to ciprofloxacin and gentamicin, 97.9% resistance to cefepime, piperacillin/tazobactam, aztreonam, ceftazidime and piperacillin, 93.9% resistance to tobramycin and 57.1% resistance to amikacin. All of the 49 isolates (100%) showed positive results in the modified Hodge test and negative results in the EDTA-disk synergy test. They all (100%) possessed the encoding gene for an intrinsic OXA-51-like carbapenemase and an acquired OXA-23-like carbapenemase in the multiplex PCR assay. PFGE patterns revealed that all isolates were clonally related from A1 to A14. CONCLUSION: It is concluded that all of the 49 IRAB isolates acquired resistance to imipenem by producing OXA-23 carbapenemase and they might have originated from a common source.
Acinetobacter Infections/epidemiology/*microbiology ; Acinetobacter baumannii/*drug effects/genetics ; Anti-Bacterial Agents/*pharmacology ; Cephalosporins/pharmacology ; Ciprofloxacin/pharmacology ; Disease Outbreaks ; Drug Resistance, Multiple, Bacterial/genetics/physiology ; Electrophoresis, Gel, Pulsed-Field ; Gentamicins/pharmacology ; Humans ; Imipenem/*pharmacology ; Korea/epidemiology ; Microbial Sensitivity Tests ; beta-Lactamases/genetics/*metabolism ; beta-Lactams/*pharmacology

BACKGROUNDNosocomial infection caused by methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) could lead to increased morbidity and mortality. In 2006, VRE nosocomial spread became a reality in our hospital since the first VRE nosocomial infection in 2003. Little is known about the prevalence of coexistence with VRE and MRSA in the patients. The primary objective of the study was to identify the molecular characteristics of epidemic MRSA clones in our hospital and the prevalence of the coexistence with MRSA and VRE in same patients during the 2-year period, 2006 - 2007.

METHODSThe clinical features, laboratory test results, and therapeutic outcomes of 129 cases who isolated MRSA collected from January 2006 to December 2007 were retrospectively analyzed. Polymerase chain reaction (PCR) was used to determine mecA-femB type and staphylococcal cassette chromosome mec (SCCmec) type. All the participants were screened for clinical and microbiological data to identify the coexistence of VRE strains with MRSA.

RESULTSOne hundred and twenty-nine MRSA isolates were included in the study: 71 (55%) from the intensive care unit, 35 (27.2%) from the surgical wards and 23 (17.8%) from the medical wards. The most frequent source of isolation of MRSA was sputum (76.7%). From seven patients we isolated MRSA and VRE (E. faecium) simultaneously during their inpatient stay. One hundred and twenty-seven (127/129, 98.4%) MRSA isolates harboured SCCmec type III, only 2 MRSA strains contained SCCmec type II. All of the 129 MRSA isolates remained sensitive to vancomycin, teicoplanin and linezolid. Higher sensitivity rates were noted for chloramphenicol 99.2% (128/129). Only 20.2% (26/129) of the MRSA isolates were sensitive to rifampin. All isolates presented resistance to multiple antimicrobial agents with high minimum inhibitory concentrations (MICs), including: beta-lactams (penicillin, oxacillin, cefoxitin, and cefazolin), tetracycline, erythromycin, gentamicin, and quinolones (ciprofloxacin, levofloxacin, and moxifloxacin).

CONCLUSIONSThe predominant MRSA clone at Beijing Chaoyang Hospital from 2006 to 2007 had the type III SCCmec element. All of the MRSA isolates were multiresistant to antimicrobial agents. Emergence of coexistence of MRSA and VRE in the same patient was not rare. Physicians should pay more attention to infections resulting from MRSA and VRE. Aggressive infection control measures should be taken to prevent the transmission of the multidrug resistance organism.

Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents ; pharmacology ; China ; Chromosomes, Bacterial ; genetics ; Enterococcus ; drug effects ; genetics ; physiology ; Gram-Positive Bacterial Infections ; epidemiology ; Hospitals ; statistics & numerical data ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; genetics ; physiology ; Microbial Sensitivity Tests ; Middle Aged ; Polymerase Chain Reaction ; Prevalence ; Staphylococcal Infections ; epidemiology ; Vancomycin Resistance

BACKGROUNDAcinetobacter baumannii has emerged as an important pathogen related to serious infections and nosocomial outbreaks around the world. However, of the frequently used methods, pulsed-field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) in Acinetobacter baumannii genotyping lack the direct molecular proof of drug resistance. This study was conducted to establish a typing method based on drug resistant gene identification in contrast to traditional PFGE and AFLP in the period of nosocomial epidemic or outbreak.

METHODSFrom January 2005 to October 2005, twenty-seven strains of Acinetobacter species from Intensive Care Units, the Second Affiliated Hospital in Ningbo were isolated, including both epidemic and sporadic events. Susceptibility test, PFGE, AFLP and drug resistance gene typing (DRGT) were carried out to confirm the drug resistance and analyze the genotyping, respectively. PFGE was used as a reference to evaluate the typeability of DRGT and AFLP.

RESULTSTwenty-seven strains of Acinetobacter displayed multiple antibiotic resistance and drug resistant genes, and beta-lactamase genes were detected in 85.2% strains. The result of DRGT was comparable to PFGE in Acinetobacter strains with different drug resistance though a little difference existed, and even suggested a molecular evolution course of different drug-resistant strains. AFLP showed great polymorphism between strains and had weak ability in distinguishing the drug resistance.

CONCLUSIONCompared to AFLP and PFGE, DRGT is useful to analyze localized molecular epidemiology of nosocomial infections and outbreaks, which would benefit clinical diagnosis and therapy.

Acinetobacter Infections ; microbiology ; Acinetobacter baumannii ; classification ; drug effects ; genetics ; Amplified Fragment Length Polymorphism Analysis ; Anti-Bacterial Agents ; pharmacology ; Drug Resistance, Multiple, Bacterial ; genetics ; physiology ; Electrophoresis, Gel, Pulsed-Field ; Genotype ; Microbial Sensitivity Tests ; Polymerase Chain Reaction