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PubMed2006

Further increase of vancomycin-resistant Enterococcus faecium, amikacin- and fluoroquinolone-resistant Klebsiella pneumoniae, and imipenem-resistant Acinetobacter spp. in Korea: 2003 KONSAR surveillance.

Monitoring temporal trends of antimicrobial resistance can provide useful information for the empirical selection of antimicrobial agents to treat infected patients and for the control of nosocomial infections. In this study, we analyzed antimicrobial resistance of clinically relevant bacteria in 2003 at Korean hospitals and at a commercial laboratory. The following organism-antimicrobial agent resistance combinations were very prevalent: oxacillin-resistant Staphylococcus aureus (68%), expanded-spectrum cephalosporin-resistant Klebsiella pneumoniae (25%), and fluoroquinolone-resistant Escherichia coli (33%), Acinetobacter spp. (58%), and Pseudomonas aeruginosa (40%). Moreover, gradual increases in vancomycin-resistant Enterococcus faecium (20%), cefoxitin-resistant E. coli (10%) and K. pneumoniae (23%), and imipenem-resistant P. aeruginosa (20%) and Acinetobacter spp. (13%) were also observed. The resistance rates of Acinetobacter spp. to most antimicrobial agents at hospitals and at the commercial laboratory were similar. Among the Acinetobacter spp. isolated at a tertiary-care hospital, 46.2% were multidrug-resistant to 9-12 of 13 antimicrobial agents, and 18.3% were panresistant. The exclusion of duplicate isolates at a tertiary-care hospital significantly lowered the proportion of oxacillin-resistant S. aureus, vancomycin-resistant E. faecium, and fluoroquinolone-resistant E. coli.

Acinetobacter↗

PubMed2003

Inhibition of vaginal lactobacilli by a bacteriocin-like inhibitor produced by Enterococcus faecium 62-6: potential significance for bacterial vaginosis.

OBJECTIVE: Bacterial vaginosis (BV) is characterized by a shift in vaginal tract ecology, which includes a decrease in the concentration and/or prevalence of facultative lactobacilli. Currently, mechanisms which could account for the disappearance of lactobacilli are not well understood. The objective of this study was to determine whether vaginal streptococci/enterococci can produce bacteriocin-like inhibitors antagonistic to vaginal lactobacilli. METHODS: Seventy strains of vaginal streptococci or enterococci were tested for antagonistic activities against vaginal lactobacilli using the deferred antagonism technique. RESULTS: One strain, Enterococcus faecium 62-6, which strongly inhibited growth of lactobacilli was selected for further characterization. The spectrum of inhibitory activity of strain 62-6 included Gram-positive organisms from the vaginal environment, although native lactobacilli from the same host were resistant to inhibitor action. Following growth in MRS broth the strain 62-6 inhibitor was shown to be heat- (100 degrees C, 30 minutes), cold- (4 degrees C, less than 114 days) and pH- (4-7) stable. The sensitivity of inhibitor-containing supernatants to pepsin and alpha-chymotrypsin suggested an essential proteinaceous component. The inhibitor was sensitive to lipase but resistant to lysozyme. Dialysis of inhibitor-containing culture supernatants suggested a molecular mass greater than 12,000 Da. All physicochemical properties were consistent with its classification as a bacteriocin-like inhibitor. Kinetic assays demonstrated a sharp onset of inhibitor production coinciding with a concentration of 62-6 of 10(7) cfu/ml, suggesting that production may be regulated by quorum sensing. CONCLUSIONS: These results may have clinical significance as a novel mechanism to account for the decline of vaginal Lactobacillus populations and contribute to both the establishment and recurrence of BV.

Bacterial Adhesion↗

PubMed1992

Daptomycin or teicoplanin in combination with gentamicin for treatment of experimental endocarditis due to a highly glycopeptide-resistant isolate of Enterococcus faecium.

Using an experimental endocarditis model, we studied the activity of daptomycin used alone or in combination with gentamicin against an Enterococcus faecium strain that was highly resistant to glycopeptides and susceptible to gentamicin. In vitro, the MIC of daptomycin was 1 micrograms/ml. In vivo, daptomycin appeared to be effective only when it was used in a high-dose regimen, i.e., 12 mg/kg of body weight every 8 h (-2.5 log10 CFU/g versus controls; P < 0.05), particularly when it was combined with gentamicin (-5.0 log10 CFU/g versus controls; P < 0.01). Since the distribution of daptomycin into cardiac vegetations, as evaluated by autoradiography, appeared to be homogeneous, the poor in vivo activity of daptomycin was considered to be related to its high degree of protein binding, as suggested by killing curves studies. Since the MIC of teicoplanin for the vancomycin-resistant E. faecium strain used in the study was only 64 micrograms/ml and since an in vitro synergy between teicoplanin at high dose and gentamicin was observed, a high-dose regimen of teicoplanin, i.e., 40 mg/kg every 12 h, was also assessed in vivo. This treatment provided marginal activity only when it was combined with gentamicin (-2.3 log10 CFU/g versus controls; P < 0.05). These results suggest that the levels of daptomycin or teicoplanin in serum required to cure experimental endocarditis caused by a highly glycopeptide-resistant strain of E. faecium would not be achievable in humans.

Animals↗

PubMed2004

Distribution of insertion sequences associated with Tn1546-like elements among Enterococcus faecium isolates from patients in Korea.

The vanA gene cluster is carried as a part of Tn1546-like elements. The genetic diversity in Tn1546-like elements has been documented previously. The differences described thus far have included the integration of insertion sequence (IS) elements IS1216V, IS1251, IS1476, and IS1542. Among these, IS1216V has been reported to be widespread in VanA enterococci of diverse geographic areas, whereas IS1542 and IS1476 have been reported only in the United Kingdom and Canada, respectively. We investigated the distribution of ISs among 20 vanA-containing Enterococcus faecium isolates from human patients in nine different university hospitals in Korea. Pulsed-field gel electrophoresis (PFGE) was performed to identify the clonality of the isolates. Moreover, PCR amplification of the internal regions of Tn1546 was performed for structural analysis of the van gene, and both DNA strands of the PCR amplicons were directly sequenced by the dideoxy termination method. The PFGE patterns revealed a high degree of clonal diversity. Structural analyses of the van gene detected IS1542 and IS1216V in the genomes of all 20 isolates, whereas it did not detect IS1476 or IS1251 in the genomes of any of the isolates. In addition, IS19 was detected in the vanS-vanH intergenic region of one isolate. These data indicate that identification of the IS within a vanA gene cluster could be a useful tool in epidemiological investigations. In addition, the distribution of ISs associated with Tn1546-like elements among the Korean isolates is therefore similar to that among European vancomycin-resistant enterococci.

Bacterial Proteins↗

PubMedDate not supplied

The bactericidal activity of ampicillin, daptomycin, and vancomycin against ampicillin-resistant Enterococcus faecium.

Ampicillin, daptomycin, and vancomycin, alone and in combination with gentamicin, were examined for bactericidal effects on ampicillin-resistant Enterococcus faecium using broth dilution minimum inhibitory concentrations (MICs) and time-kill studies. We tested 12 ampicillin-resistant isolates and demonstrated the following MICs and MBCs, respectively: ampicillin, greater than or equal to 32 micrograms/ml and greater than 256 micrograms/ml; daptomycin, less than or equal to 4 micrograms/ml and less than or equal to 16 micrograms/ml; and vancomycin, less than or equal to 4 micrograms/ml and greater than 64 micrograms/ml. Time-kill studies demonstrated that daptomycin alone had marked activity against the ampicillin-resistant E. faecium and that the addition of gentamicin resulted in synergistic killing. In addition, ampicillin and vancomycin were not bactericidal for the ampicillin-resistant isolates without the addition of gentamicin. The present study supports the consideration of daptomycin alone or in combination with an aminoglycoside as an alternative therapy for ampicillin-resistant enterococci, although additional clinical experience is now necessary.

Ampicillin↗

PubMed2003

Metschnikowia bicuspidata and Enterococcus faecium co-infection in the giant freshwater prawn Macrobrachium rosenbergii.

In May 2001, an epizootic yeast and bacterial co-infection in the giant freshwater prawn Macrobrachium rosenbergii occurred in Taiwan causing a cumulative mortality of 25%. The diseased prawns had a yellowish-brown body color, milky hemolymph, opaque, whitish muscles, and were approximately 7 mo old with total lengths ranging from 8 to 10 cm. Histopathological examination showed marked edema, yeast infiltration, and necrotic lesions with inflammation in the muscles, hepatopancreas and other internal organs. We isolated 2 pathogens from the diseased prawns, one was a yeast (AOD081MB) and the other a gram-positive coccus (AOD081EF). The gram-positive coccus was identified as Enterococcus faecium by the API 20 Strepsystem, conventional biochemical tests, and it had 99% 16S rDNA sequence identity (GenBank Accession Number AJ276355) to E. faecium (GenBank Accession Number AF529204). The sequence of a PCR product from the D1/D2 domain of 26S rDNA (GenBank Accession Number AF529297) from the yeast gave 99% sequence identity to Metschnikowia bicuspidata (GenBank Accession Number U44822). Experimental infections with these isolates produced gross signs and histopathological changes similar to those observed in the naturally infected prawns. The lethal doses (LD50) for isolate E. faecium AOD081EF, M. bicuspidata AOD081MB and the co-infection were 4.7 x 10(4), 2.6 x 10(2), and 2.4 x 10(2) colony-forming units prawn(-1), respectively. This is the first report of a confirmed co-infection of M. bicuspidata and E. faecium in prawn aquaculture.

Animals↗

PubMed2026

Clinical Characteristics and Genomic Analysis of Vancomycin-Resistant Enterococcus faecium in a Tertiary Hospital in Huizhou.

OBJECTIVE: To characterize the clinical and genomic features of vancomycin-resistant enterococci (VRE) in a tertiary hospital in Huizhou and identify risk factors to inform local infection control. METHODS: A retrospective study included 58 VRE and 25 vancomycin-susceptible Enterococci (VSE) strains (August 2023-May 2025). Clinical data and antimicrobial susceptibility were analyzed; whole-genome sequencing (WGS) was performed on 54 VRE strains. RESULTS: Midstream urine was the primary VRE-positive specimen. ICU admission, polyantibiotic use (≥3 agents), and urinary catheterization were key risk factors for VRE. All VRE isolates were Enterococcus faecium and showed a predominantly clonal population structure, dominated by CC17/ST80 (68.8%) and CC2/ST106 (64.6%) under the two multilocus sequence typing schemes; five novel STs were ultimately identified in the latter scheme. VRE was universally resistant to ampicillin, with high resistance to penicillin, levofloxacin, and teicoplanin, while linezolid and tigecycline remained effective. Genotypically, 94.8% carried vanA, 100% carried virulence gene esp, and aminoglycoside and macrolide resistance genes were prevalent. A unique VRE strain (VRE48) showed resistance without canonical van genes, harboring a Ddl Ser210Tyr mutation.

Humans↗

PubMed2005

Structure-activity relationships of different beta-lactam antibiotics against a soluble form of Enterococcus faecium PBP5, a type II bacterial transpeptidase.

Penicillin-binding proteins (PBPs) catalyze the essential reactions in the biosynthesis of cell wall peptidoglycan from glycopeptide precursors. beta-Lactam antibiotics normally interfere with this process by reacting covalently with the active site serine to form a stable acyl-enzyme. The design of novel beta-lactams active against penicillin-susceptible and penicillin-resistant organisms will require a better understanding of the molecular details of this reaction. To that end, we compared the affinities of different beta-lactam antibiotics to a modified soluble form of a resistant Enterococcus faecium PBP5 (Delta1-36 rPBP5). The soluble protein, Delta1-36 rPBP5, was expressed in Escherichia coli and purified, and the NH(2)-terminal protein sequence was verified by amino acid sequencing. Using beta-lactams with different R1 side chains, we show that azlocillin has greater affinity for Delta1-36 rPBP5 than piperacillin and ampicillin (apparent K(i) = 7 +/- 0.3 microM, compared to 36 +/- 3 and 51 +/- 10 microM, respectively). Azlocillin also exhibits the most rapid acylation rate (apparent k(2) = 15 +/- 4 M(-1) s(-1)). Meropenem demonstrates an affinity for Delta1-36 rPBP5 comparable to that of ampicillin (apparent K(i) = 51 +/- 15 microM) but is slower at acylating (apparent k(2) = 0.14 +/- 0.02 M(-1) s(-1)). This characterization defines important structure-activity relationships for this clinically relevant type II transpeptidase, shows that the rate of formation of the acyl-enzyme is an essential factor determining the efficacy of a beta-lactam, and suggests that the specific side chain interactions of beta-lactams could be modified to improve inactivation of resistant PBPs.

Acylation↗

PubMed2003

Supplementation of food with Enterococcus faecium (SF68) stimulates immune functions in young dogs.

The gut microflora play a crucial role in several physiologic functions of the host, including maturation of the gut-associated lymphoid tissues during the first months of life. Oral administration of probiotic lactic acid bacteria (LAB) modulates the immune system of humans and some laboratory animals. This effect has never been examined in dogs; therefore, our aim was to study the capacity of a probiotic LAB to stimulate immune functions in young dogs. Puppies were allotted to two groups receiving either a control diet or a diet supplemented with 5 x 10(8) colony forming units (cfu)/d of probiotic Enterococcus faecium (SF68) from weaning to 1 y of age. Fecal and blood samples were collected from the dogs at different time points for the measurement of fecal immunoglobulin (Ig)A, circulating IgG and IgA, and the proportions of lymphoid cell subsets. Fecal IgA and canine distemper virus (CDV) vaccine-specific circulating IgG and IgA were higher in the group receiving the probiotic than in controls. There were no differences in the percentages of CD4(+) and CD8(+) T cells between the groups, but the proportion of mature B cells [CD21(+)/major histocompatibility complex (MHC) class II(+)] was greater in those fed the probiotic. These data show for the first time that a dietary probiotic LAB enhance specific immune functions in young dogs, thus offering new opportunities for the utilization of probiotics in canine nutrition.

Animal Feed↗

PubMed1997

Emergence and dissemination of a highly vancomycin-resistant vanA strain of Enterococcus faecium at a large teaching hospital.

We prospectively identified patients at the Massachusetts General Hospital from whom vancomycin-resistant enterococci (VRE) were isolated from a clinical specimen from 1 January 1991 through 31 December 1995. VRE strains were available from 139 (82%) of the 169 patients with clinical cases. Of these, 39 (28%) were identical or closely related by pulsed-field gel electrophoresis (i.e., VRE type A strain), including 38 (43%) of 89 VRE strains in 1995. By multivariate analysis, acquisition of the VRE type A strain was associated with receipt of clindamycin (odds ratio [OR] = 10.5), 15 or more days of hospitalization before the first isolation of VRE (OR = 2.9), and residence on one of the general medical floors (OR = 7.8). The VRE type A strain was a vanA strain of Enterococcus faecium and was highly resistant to all antimicrobial agents tested except chloramphenicol. These findings document the rapid dissemination of a highly resistant strain of E. faecium among patients and among other extant VRE strains at the Massachusetts General Hospital in 1995.

Adolescent↗

PubMed2004

Determining incidence of extended spectrum beta-lactamase producing Enterobacteriaceae, vancomycin-resistant Enterococcus faecium and methicillin-resistant Staphylococcus aureus in 38 centres from 17 countries: the PEARLS study 2001-2002.

The PEARLS study prospectively monitored selected nosocomial pathogens from 38 centres in 13 European, three Middle Eastern countries and South Africa during 2001-2002. Extended spectrum beta-lactamase (ESBL) production rates among Escherichia coli, Klebsiella pneumoniae, and Enterobacter spp. were 5.4% (142/2609), 18.2% (401/2,206) and 8.8% (204/2,328), respectively, for all study sites. The overall ESBL production rate for the combined Enterobacteriaceae was 10.5% (747/7,143), highest in Egypt, 38.5%, and Greece, 27.4%, and lowest in The Netherlands, 2.0%, and Germany, 2.6%. IEF, PCR and DNA sequencing determined 10.7% false positives among Enterobacter spp. when using NCCLS guidelines to screen for ESBL production. The prevalence of nosocomial methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium was 32.4% (294/908) and 8.7% (83/949), respectively. PEARLS provides baseline data against which prospective changes in resistant determinants and outcomes can be measured in this ongoing study.

Anti-Bacterial Agents↗

PubMed1996

Testing the efficacy of a molecular surveillance network: methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF) genotypes in six hospitals in the metropolitan New York City area. The BARG Initiative Pilot Study Group. Bacterial Antibiotic Resistance Group.

Molecular fingerprinting techniques are rapidly becoming indispensable tools for hospital epidemiology. On the other hand, the relative complexity and unfamiliarity of these techniques to most hospital diagnostic laboratories limit their usefulness. In an attempt to provide a solution for this dilemma, we tested the feasibility and efficacy of a cooperative venture in which molecular typing of isolates recovered from patients in six hospitals was performed at two microbiology research laboratories with expertise in these techniques. In a small preliminary study, 30 methicillin-resistant Staphylococcus aureus (MRSA) and 30 vancomycin-resistant Enterococcus faecium (VREF) isolates were collected over a 3-week period from six hospitals in the metropolitan New York area and transported to the Laboratory of Microbiology at The Rockefeller University during the summer months of 1994. Nineteen of the 27 confirmed MRSA isolates were closely related strains carrying the same mecA and the same Tn554 polymorphs in a pulsed-field gel electrophoresis (PFGE) background represented by closely related subtypes of a single pattern, indicating the wide distribution of this MRSA clone among the participating hospitals. Typing of the same 27 MRSA isolates was also performed at the Tuberculosis Center of the Public Health Research Institute and identical results were obtained. The 29 confirmed VREF isolates were highly heterogeneous and belonged to as many as 23 distinct clonal types as defined by PFGE patterns and probing with vanA. Characterization of the 60 isolates by these methods was completed in one month of full-time effort by a single experienced laboratory assistant guided by a doctoral-level expert in molecular fingerprinting techniques. The collection of samples for both MRSA and VREF was not intended to address epidemiological questions but to determine the feasibility of a multicenter study. On the basis of our preliminary findings we are encouraged that a larger cooperative effort is possible and with the correct sampling method we believe that epidemiological and surveillance studies could be accomplished that would provide a tracking system to assist hospitals, clinics, and chronic care facilities in controlling the spread of multidrug-resistant pathogens.

Anti-Bacterial Agents↗

PubMed1997

Effect of a vancomycin restriction policy on ordering practices during an outbreak of vancomycin-resistant Enterococcus faecium.

BACKGROUND: With the development of nosocomial pathogens that are resistant to multiple antimicrobial agents, reasonable restriction of antibiotic use has become a priority. METHODS: During an outbreak of vancomycin-resistant enterococcal infections, an audit of vancomycin hydrochloride use was conducted during October 3 through 21, 1994, and January 24 through February 2, 1995. During these periods, all orders for vancomycin were reviewed by clinical pharmacists. Use was classified as either appropriate or inappropriate based on recommendations by the Hospital Infection Control Practice Advisory Committee (HICPAC) of the Centers for Disease Control and Prevention, Atlanta, Ga. A policy restricting the use of vancomycin was adopted in November 1994. RESULTS: During the first audit in October 1994, 61% of vancomycin orders were considered inappropriate according to HICPAC criteria. At the time of this audit, the first cases of an outbreak of nosocomial vancomycin-resistant Enterococcus faecium had been detected. The follow-up audit showed that 30% of vancomycin orders were inappropriate by HICPAC criteria (P < .001). Overall use of vancomycin decreased by 50% and remained at this lower level for the following year. CONCLUSION: The institution of a vancomycin restriction policy was associated with a reduction of both inappropriate drug orders and total use.

Anti-Bacterial Agents↗

PubMed2005

Clonal spread of a vancomycin-resistant Enterococcus faecium strain among bloodstream-infecting isolates in Italy.

Recent data indicated that the rate of vancomycin resistance in bloodstream-infecting enterococcal isolates in Italy is one of the highest in Europe. The aims of this study were to characterize bloodstream-infecting vancomycin-resistant enterococci (VRE) obtained from various Italian hospitals and to establish whether the isolates were clonally related. During the years 2001 to 2003, a total of 39 VRE isolates were obtained from 19 hospital laboratories in various areas of Italy. Species identification and resistance genotypes of the isolates were obtained by multiplex PCR. Further characterization included antibiotic susceptibility testing, pulsed-field gel electrophoresis (PFGE) of SmaI-digested genomic DNA, detection of virulence genes (esp and hyl), and multilocus sequence typing (MLST) of selected isolates. VRE were identified as 31 Enterococcus faecium (VREfm) isolates and 8 E. faecalis isolates. All but one isolate carried the vanA gene; one VREfm isolate carried the vanB gene. Analysis of the PFGE profiles showed that 28 VREfm isolates shared a similar electrophoretic profile, designed type 1, and were clonally related. All type 1 isolates were resistant to ampicillin, streptomycin, gentamicin, and rifampin and were positive for the esp gene. MLST identified an allelic profile (ST78) comprising purK allele 1, belonging to the C1 clonal lineage, characteristic of human infection and hospital outbreak isolates. The vanB-carrying VREfm isolate, of PFGE type 2, was shown to be a single-locus variant of ST78. Our data indicate that the recent increase in the number of bloodstream infections caused by VRE in Italy is due to the spread of a hospital-adapted, multidrug-resistant VREfm clone belonging to an internationally disseminated lineage.

Anti-Bacterial Agents↗

PubMed2004

Antagonistic activity against Helicobacter pylori infection in vitro by a strain of Enterococcus faecium TM39.

Lactic acid bacteria (LAB) strains from infant feces were screened for anti-Helicobacter pylori use. In the beginning, we selected the strains based on their capability to adhere to the human intestinal epithelial cell (Int-407), colonial enterocyte-like Caco-2 cell, human cervical epithelioid carcinoma cell (HeLa), and human gastric carcinoma cell (TSGH 9201). Then, acid and bile salt tolerance of these LAB strains was evaluated. In addition, the ability of these LAB strains to inhibit the growth of H. pylori and to expel H. pylori cells from TSGH 9201 were studied. The spent culture supernatant (SCS) of a selected strain TM39, i.e., TM39-SCS, significantly inhibited the viability of H. pylori in vitro. It also inhibited the urease activity of H. pylori in vitro. For these antagonistic effects, in addition to pH and lactic acid, some factors in TM39-SCS might play the major role. Treatment of H. pylori with the SCS or cells of strain TM39 significant reduced its binding to TSGH 9201 cells. Although strain TM39 is identified as Enterococcus faecium, it is not vancomycin resistant and is proved to be safe through the invasion study and a 28-day feeding study with Wistar rats.

Animals↗

PubMed2006

Novel mechanism of resistance to glycopeptide antibiotics in Enterococcus faecium.

Glycopeptides and beta-lactams are the major antibiotics available for the treatment of infections due to Gram-positive bacteria. Emergence of cross-resistance to these drugs by a single mechanism has been considered as unlikely because they inhibit peptidoglycan polymerization by different mechanisms. The glycopeptides bind to the peptidyl-D-Ala(4)-D-Ala(5) extremity of peptidoglycan precursors and block by steric hindrance the essential glycosyltransferase and D,D-transpeptidase activities of the penicillin-binding proteins (PBPs). The beta-lactams are structural analogues of D-Ala(4)-D-Ala(5) and act as suicide substrates of the D,D-transpeptidase module of the PBPs. Here we have shown that bypass of the PBPs by the recently described beta-lactam-insensitive L,D-transpeptidase from Enterococcus faecium (Ldt(fm)) can lead to high level resistance to glycopeptides and beta-lactams. Cross-resistance was selected by glycopeptides alone or serially by beta-lactams and glycopeptides. In the corresponding mutants, UDP-MurNAc-pentapeptide was extensively converted to UDP-MurNAc-tetrapeptide following hydrolysis of D-Ala(5), thereby providing the substrate of Ldt(fm). Complete elimination of D-Ala(5), a residue essential for glycopeptide binding, was possible because Ldt(fm) uses the energy of the L-Lys(3)-D-Ala(4) peptide bond for cross-link formation in contrast to PBPs, which use the energy of the D-Ala(4)-D-Ala(5) bond. This novel mechanism of glycopeptide resistance was unrelated to the previously identified replacement of D-Ala(5) by D-Ser or D-lactate.

Alanine↗

PubMed1991

[A simple apparatus for the determination of the resistance of bioindicators to saturated steam at temperatures less than 100 degrees C., tested with Enterococcus faecium as test microbe].

An apparatus is described by means of which the resistance of microbiological indicators to water vapor at temperatures below 100 degrees C can be determined. The apparatus can be assembled from parts generally available in laboratories. The principle of the apparatus consists in the production of water vapor of the desired temperature under conditions of reduced pressure and its recondensation to water after having passed a special chamber. Accordingly, the device consists of a heated round-bottom flask serving as steam generator, an exposure chamber (B), and a condenser (D) attached to a receiver (E). The bioindicators are exposed to the water vapor in the exposure chamber. A bypass located between the steam generator and the condenser allows for continuous operation even when the exposure chamber is opened. The reduced pressure was achieved by means of a waterjet pump and adjusted by two tandem-joined pressure-regulating valves as needed. The apparatus was tested using water vapor of 73, 75 and 77 degrees C, respectively, and bioindicators containing Enterococcus faecium as test organism. In the range of exposure periods in which bioindicators change from the status "all indicators having surviving test organisms" to the status "all indicators free from surviving test organisms" the bioindicators showed D values of 5.7, 4.4 and 2.9 min, respectively. For the temperature dependence of resistance a z value of 12.5 Kelvin resulted.

Disinfection↗

PubMed1993

Colonial variation in vancomycin resistant Enterococcus faecium.

Vancomycin resistant enterococci are increasingly being isolated from inpatients. This report describes the colonial variation present in most isolates of vancomycin resistant Enterococcus faecium obtained at this hospital. Colonial variants within the same culture were indistinguishable by antimicrobial susceptibility, biochemical reactions, and ribotyping. Failure to appreciate this colonial variation will lead to pure cultures being regarded as contaminated or mixed.

Cross Infection↗