Enterococci have emerged as a major nosocomial pathogen and as an ever-increasing problem in antimicrobial resistance. They are ubiquitous in the intestinal flora of humans and animals and inherently resistant to a wide array of antimicrobial agents, and, more alarmingly, they seem to have a potential facility for acquiring new resistance determinants, including beta-lactamase production, high-level resistance to aminoglycosides, and recently, glycopeptide resistance. Collectively, all of these properties make enterococci one of most difficult nosocomial pathogens to treat and control today. The purpose of this review was to examine the epidemiology, the mechanisms, and laboratory detection of resistance of enterococci to the two major groups of antibiotics: aminoglycosides and glycopeptides.
Aminoglycosides/pharmacology ; Antibiotics, Glycopeptide/pharmacology ; Drug Resistance, Microbial/physiology* ; Enterococcus/physiology* ; Enterococcus/drug effects ; Epidemiologic Methods ; Human

AIMTo study the influence of enterococci on human sperm membrane in vitro.

METHODSEjaculated human sperm were artificially infected with beta-hemolytic or non-beta-hemolytic enterococci at the bacteria: sperm ratio of 50:1 at 37 degrees . Sperm membrane integrity was examined after incubation for 1, 3 and 5 h by hypoosmotic swelling (HOS) test and electron microscopy.

RESULTSSperm infected with beta-hemolytic enterococci had lower HOS scores compared with non-beta-hemolytic strains or uninfected control (P < 0.01). The HOS test scores of sperm infected with beta-hemolytic enterococci increased in the presence of phosphatidylcholine, an inhibitor of hemolysin. Non-beta-hemolytic strains showed no significant difference in swelling rate, compared with the control group (P > 0.05). It was shown by electron microscopy that beta-hemolytic enterococci caused significant rupture of human sperm membrane.

CONCLUSIONBeta-hemolytic enterococci caused human sperm membrane injury, and might be mediated by the hemolysin of enterococci.

Cell Membrane ; drug effects ; microbiology ; Ejaculation ; Enterococcus ; physiology ; Feces ; microbiology ; Humans ; Male ; Phosphatidylcholines ; pharmacology ; Reference Values ; Spermatozoa ; drug effects ; microbiology ; ultrastructure

OBJECTIVETo investigate the relationship between the expression of the quorum-sensing related genes during Enterococcus faecalis(Ef) biofilm formation.

METHODSEf biofilms model was established in vitro and film formation process was observed by confocal laser scanning microscope at 6, 12, 24 and 48 hours respectively.Quantification of biofilms was achieved by staining with crystal violet.Real-time fluorescence quantitative PCR method was used to detect the expression of fsrB, gelE and sprE genes in the process of Ef biofilm formation.

RESULTSA lot of live and dead bacteria unevenly distributed in Ef biofilm. The quantity of biofilms increased with time within 24 hours and was 0 h:0.00 ± 0.00, 6 h:1.09 ± 0.13, 12 h:2.10 ± 0.79, 24 h:3.30 ± 0.13, which was significantly different among the 4 time period(P < 0.05). The quantity of biofilm at 48 h(3.51 ± 0.01) increased slightly compared with 24 h(3.30 ± 0.13) , but did not show significant difference.Quantitative real-time PCR showed that the expression of quorum-sensing related fsrB increased with time within 24 hours and was 0 h:9.98 ± 0.46, 6 h:23.45 ± 1.13, 12 h:47.30 ± 2.49, 24 h: 331.30 ± 2.18, which was significantly different among the 4 time period(P < 0.05). The expression of gelE was 0 h: 6.54 ± 0.73, 6 h: 14.26 ± 1.24, 12 h: 37.47 ± 2.35, 24 h:264.80 ± 5.10(P < 0.05). The expression of sprE was 0 h: 7.72 ± 0.74, 6 h: 21.15 ± 0.96, 12 h:49.87 ± 3.18, 24 h:441.89 ± 7.74, which was significantly different among the 4 time period(P < 0.05).

CONCLUSIONSThe fsrB, gelE and sprE genes are closely related to the biofilm formation in Ef.

Bacterial Proteins ; metabolism ; Biofilms ; growth & development ; Enterococcus faecalis ; genetics ; metabolism ; physiology ; Gelatinases ; metabolism ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Quorum Sensing ; Serine Proteases ; metabolism

OBJECTIVE: To construct a model of Enterococcus faecalis (E. faecalis) infection in dentinal tubules by gradient centrifugation and to evaluate the antibacterial effect of low-temperature plasma on E. faecalis in dentinal tubules. METHODS: Standard dentin blocks of 4 mm×4 mm×2 mm size were prepared from single root canal isolated teeth without caries, placed in the E. faecalis bacterial solution, centrifuged in gradient and incubated for 24 h to establish the model of dentinal tubule infection with E. faecalis. The twenty dentin blocks of were divided into five groups, low-temperature plasma jet treatment for 0, 5 and 10 min, calcium hydroxide paste sealing for 7 d and 2% chlorhexidine gel sealing for 7 d. Scanning electron microscopy and confocal laser scanning microscope were used to assess the infection in the dentinal tubules and the antibacterial effect of low-temperature plasma. RESULTS: The results of scanning electron microscopy and confocal laser scanning microscopy showed that after 24 h of incubation by gradient centrifugation, E. faecalis could fully enter the dentinal tubules to a depth of more than 600μm indicating that this method was time-saving and efficient and could successfully construct a model of E. faecalis infection in dentinal tubules. Low-temperature plasma could enter the dentinal tubules and play a role, the structure of E. faecalis was still intact after 5 min of low-temperature plasma treatment, with no obvious damage, and after 10 min of low-temperature plasma treatment, the surface morphology of E. faecalis was crumpled and deformed, the cell wall was seriously collapsed, and the normal physiological morphology was damaged indicating that the majority of E. faecalis was killed in the dentinal tubules. The antibacterial effect of low-temperature plasma treatment for 10 min exceeded that of the calcium hydroxide paste sealing for 7 d and the 2% chlorhexidine gel sealing for 7 d. These two chemicals had difficulty entering deep into the dentinal tubules, and therefore only had a few of antibacterial effect on the bacterial biofilm on the root canal wall, and there was also no significant damage to the E. faecalis bacterial structure. CONCLUSION Gradient centrifugation could establish the model of E. faecalis dentin infection successfully. Low-temperature plasma treatment for 10 min could kill E. faecalis in dentinal tubules effectively, which is superior to the calcium hydroxide paste sealing for 7 d and the 2% chlorhexidine gel sealing for 7 d.
Chlorhexidine/pharmacology* ; Calcium Hydroxide/pharmacology* ; Enterococcus faecalis/physiology* ; Temperature ; Dentin ; Biofilms ; Anti-Bacterial Agents/pharmacology* ; Root Canal Irrigants/pharmacology* ; Dental Pulp Cavity

Antimicrobial resistance of bacteria has become a worldwide problem. Available data suggest that the resistance problem is comparatively more serious in Korea. In large hospitals, the proportion of methicillin-resistant Staphylococcus aureus (MRSA) has been reported at over 70%, and of penicillin-nonsusceptible Streptococcus pneumoniae at around 70%. Infection or colonization of vancomycin-resistant enterococci has started to increase. Extended-spectrum beta-lactamase producing Escherichia coli and Klebsiella pneumoniae has become widespread and even carbapenem-resistant Pseudomonas aeruginosa has been increasing. Community-acquired pathogens such as Salmonella, Shigella and Neisseria gonorrhoeae are often resistant to various antimicrobial agents. The prevalence of resistant bacteria can lead to erroneous empirical selection of either noneffective or expensive drugs, prolonging hospitalization and higher mortality. The emergence and spread of resistant bacteria are unavoidable unless antimicrobial agents are not used at all. The high prevalence of resistant bacteria in Korea seems to be related to antibiotic usage: 1) easy availability without prescription at drug stores, 2) injudicious use in hospitals, and 3) uncontrolled use in agriculture, animal husbandry, and fisheries. Nosocomial infection is an important factor in the spread of resistant bacteria. Antimicrobial resistance problems should be regarded as the major public health concern in Korea. It is urgently required to ban the sale of antibiotics without prescription, to use antibiotics more judiciously in hospitals by intensive teaching of the principles of the use of antibiotics, and to establish better control measures of nosocomial infections. Regulation of antimicrobials for other than human use should also be required. These issues are not easy to address and require the collective action of governments, the pharmaceutical industry, health care providers, and consumers.
Bacterial Infections/drug therapy ; Bacterial Physiology* ; Drug Resistance, Microbial/physiology* ; Enterococcus/drug effects ; Gram-Negative Bacterial Infections/drug therapy ; Human ; Korea ; Pneumococcal Infections/drug therapy ; Staphylococcal Infections/drug therapy

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

BACKGROUNDGram-positive bacteria such as Staphylococcus aureus have been a common cause of infection among liver transplant (LT) recipients in recent decades. The understanding of local epidemiology and its evolving trends with regard to pathogenic spectra and antibiotic susceptibility is beneficial to prophylactic and empiric treatment for LT recipients. This study aimed to investigate etiology, timing, antibiotic susceptibility and risk factors for multidrug resistant (MDR) Gram-positive coccal bacteremia after LT.

METHODSA cohort analysis of prospectively recorded data was performed to investigate etiologies, timing, antibiotic susceptibility and risk factors for MDR Gram-positive coccal bacteremia in 475 LT recipients.

RESULTSIn 475 LT recipients in the first six months after LT, there were a total of 98 episodes of bacteremia caused by Gram-positive cocci in 82 (17%) patients. Seventy-five (77%) bacteremic episodes occurred in the first post-LT month. The most frequent Gram-positive cocci were methicillin-resistant coagulase-negative staphylococcus (CoNS, 46 isolates), methicillin-resistant Staphylococcus aureus (MRSA, 13) and enterococcus (34, E. faecium 30, E. faecalis 4). In all Gram-positive bacteremic isolates, 59 of 98 (60%) were MDR. Gram-positive coccal bacteremia and MDR Gram-positive coccal bacteremia predominantly occurred in patients with acute severe exacerbation of chronic hepatitis B and with fulminant/subfulminant hepatitis. Four independent risk factors for development of bacteremia caused by MDR Gram-positive coccus were: LT candidates with encephalopathy grades II - IV (P = 0.013, OR: 16.253, 95%CI: 1.822 - 144.995), pre-LT use of empirical antibiotics (P = 0.018, OR: 1.029, 95%CI: 1.002 - 1.057), post-LT urinary tract infections (P < 0.001, OR: 20.340, 95%CI: 4.135 - 100.048) and abdominal infection (P = 0.004, OR: 2.820, 95%CI: 1.122 - 10.114). The main infectious manifestations were coinfections due to gram-positive cocci and gram-negative bacilli.

CONCLUSIONSMethicillin-resistant CoNS and enterococci are predominant pathogens among LT recipients with Gram-positive coccal bacteremia. Occurrences of Gram-positive coccal bacteremia may be associated with the severity of illness in the perioperative stage.

Anti-Bacterial Agents ; pharmacology ; Bacteremia ; etiology ; microbiology ; Coagulase ; metabolism ; Drug Resistance, Multiple, Bacterial ; Enterococcus ; drug effects ; enzymology ; physiology ; Gram-Positive Bacterial Infections ; enzymology ; microbiology ; transmission ; Humans ; Liver Diseases ; microbiology ; Liver Transplantation ; adverse effects ; Risk Factors ; Staphylococcal Infections ; enzymology ; microbiology ; transmission ; Staphylococcus ; drug effects ; enzymology ; physiology

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

The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate (MTA) was studied by scanning electron microscopy (SEM). Single-rooted human premolars (n=60) were instrumented to an apical size #50/0.06 using ProFile and treated as follows: Group 1 (n=10) was filled with phosphate buffered saline (PBS); Group 2 (n=10) was incubated with Enterococcus faecalis for 3 weeks, and then filled with PBS; Group 3 (n=20) was obturated orthograde with a paste of OrthoMTA (BioMTA, Seoul, Korea) and PBS; and Group 4 (n=20) was incubated with E. faecalis for 3 weeks and then obturated with OrthoMTA-PBS paste. Following their treatments, the coronal openings were sealed with PBS-soaked cotton and intermediate restorative material (IRM), and the roots were then stored in PBS for 1, 2, 4, 8 or 16 weeks. After each incubation period, the roots were split and their dentin/MTA interfaces examined in both longitudinal and horizontal directions by SEM. There appeared to be an increase in intratubular mineralization over time in the OrthoMTA-filled roots (Groups 3 and 4). Furthermore, there was a gradual entombment of bacteria within the dentinal tubules in the E. faecalis inoculated MTA-filled roots (Group 4). Therefore, the orthograde obturation of root canals with OrthoMTA mixed with PBS may create a favorable environment for bacterial entombment by intratubular mineralization.
Aluminum Compounds ; therapeutic use ; Calcification, Physiologic ; physiology ; Calcium Compounds ; therapeutic use ; Crystallization ; Dental Pulp Cavity ; microbiology ; Dentin ; microbiology ; Drug Combinations ; Enterococcus faecalis ; ultrastructure ; Humans ; Methylmethacrylates ; therapeutic use ; Microscopy, Electron, Scanning ; Oxides ; therapeutic use ; Root Canal Filling Materials ; therapeutic use ; Root Canal Obturation ; methods ; Root Canal Preparation ; instrumentation ; Silicates ; therapeutic use ; Time Factors ; Zinc Oxide-Eugenol Cement ; therapeutic use

Strongyloides stercoralis is a soil transmitted intestinal nematode that is endemic in the tropical and subtropical regions. In most individuals who are infected, chronic, usually asymptomatic, gastrointestinal infection persists. But, in immunocompromized hosts or in patients receiving immunosuppressive therapy, autoinfection of S. stercoralis may result in the dissemination of larvae, leading to fatal hyperinfection and increased rate of complications. We report a case of hyperinfective strongyloidiasis with bacterial meningitis in a patient receiving steroid therapy. Strongyloidiasis was diagnosed by the presence of filariform larvae of S. stercoralis in the bronchoalveolar lavage cytology and upper gastrointestinal endoscopic biopsy specimen. Her clinical symptoms had progressively aggravated and developed bacterial meningitis during treatment. She died despite aggressive antibiotic and antihelminthic therapy.
Adrenal Insufficiency/drug therapy ; Aged ; Animals ; Bronchoalveolar Lavage Fluid/parasitology ; Endoscopy, Gastrointestinal ; Enterococcus faecium/isolation & purification ; Female ; Humans ; Immunocompromised Host ; Intestinal Mucosa/pathology ; Larva/physiology ; Magnetic Resonance Imaging ; Meningitis, Bacterial/complications/*diagnosis/microbiology ; Steroids/adverse effects/therapeutic use ; Strongyloides stercoralis/growth & development/isolation & purification ; Strongyloidiasis/complications/*diagnosis/parasitology