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PubMed2002

Distribution of enterococci in Hong Kong.

OBJECTIVES: To study the distribution of hospital isolates of enterococci from urines, bile, blood and body fluids and to evaluate different methods for the identification of enterococci. METHODS: Enterococci isolated from urine, bile, blood and body fluids collected during 1997 and 1998 were identified by polymerase chain reaction (PCR), API 20 Strep and conventional biochemical tests. RESULTS: A total of 498 non-duplicate enterococci were studied: 398 and 43 isolates from urine and bile, respectively, 49 from blood, two from cerebrospinal fluid and six from body fluids. Both API 20 Strep and PCR gave the same identification results for 240 Enterococcus faecalis isolates, 45 E. faecium isolates and one isolate each of E. gallinarum and E. Casseliflavus. These isolates were re-defined by conventional biochemical tests. PCR could correctly identify 303 (98%) isolates while API 20 Strep could only correctly identify 287 (93%) isolates (99% of E. faecalis and 57-87% of the other Enterococcus sp.). Thus, PCR was used in the identification of the remaining isolates and the identity of isolates other than E. faecalis was subsequently confirmed by biochemical tests. CONCLUSIONS: The majority of enterococci isolated was E. faecalis (81%) while only 15% were E. faecium and 4% the other enterococcal species. PCR could correctly identify E. faecalis while the identity of other enterococcal species had to be confirmed by biochemical tests.

Bacterial Typing Techniques↗
PubMed2000

Vancomycin-resistant enterococci.

Over the last 2 decades, enterococci, formerly viewed as organisms of minimal clinical impact, have emerged as important hospital-acquired pathogens in immunosuppressed patients and intensive care units (ICUs). Vancomycin resistance in enterococci is increasing steadily. Vancomycin-resistant enterococci (VRE) composed 26% of nosocomial enterococci in 1999, a 47% increase from 1994 to 1998. More that 25% of ICU enterococci are resistant to vancomycin. Antimicrobial therapy is problematic for all VRE, but particularly when bactericidal activity is necessary. Quinipristin-dalfopristin and linezolid are 2 new approved antimicrobials for the treatment of recalcitrant infections caused byVRE. Control of the transmission of VRE, although successful in preventing infections, is neither simple nor inexpensive, and VRE has become endemic in many hospitals. However, endemicity poses serious risks to the health of current and future patients, and of itself, is expensive. Data on the cost-effectiveness of VRE prevention programs are currently lacking and urgently needed; however, because the added cost of a single VRE infection far exceeds those of gowns, gloves, and screening, it seems likely that such control programs represent significant cost savings for those hospitals willing to undertake them.

Cross Infection↗
PubMed2002

Antibiotic resistance of faecal enterococci in poultry, poultry farmers and poultry slaughterers.

The prevalence of resistance in enterococci to antibiotics, commonly used for therapy in poultry or as antimicrobial growth promoters (AMGPs), was determined in faecal samples of two chicken populations: broilers in which antibiotic and AMGP use is common and laying-hens with a low antibiotic usage. In addition faecal samples were examined from three human populations: broiler farmers, laying-hen farmers and poultry slaughterers. MICs of an extended panel of antibiotics for a randomly chosen gentamicin- or vancomycin-resistant enterococcal isolate from each faecal specimen were also determined. The prevalence of resistance for all antibiotics tested was higher in broilers than in laying-hens. Resistance in faecal enterococci of broiler farmers was for nearly all antibiotics higher than those observed in laying-hen farmers and poultry slaughterers. The overall resistance in broilers was correlated with the resistance in broiler farmers and in poultry slaughterers. No correlation between the results obtained in the laying-hens with any of the other populations was found. The 27 gentamicin-resistant isolates all showed high-level resistance to gentamicin and two of these isolates, both Enterococcus faecium, were resistant to all antibiotics tested, except vancomycin. The 73 vancomycin-resistant enterococci (VRE) isolated from the five populations belonged to four different species and in all isolates the vanA gene cluster was detected by blot hybridization. The pulsed-field gel electrophoresis (PFGE) patterns of these vancomycin-resistant enterococci were quite heterogeneous, but Enterococcus hirae isolates with the same or a closely related PFGE pattern were isolated at two farms from the broiler farmer and from broilers. Molecular characterization of vanA-containing transposons of these isolates showed that similar transposon types, predominantly found in poultry, were present. Moreover, similar vanA elements were not only found in isolates with the same PFGE pattern but also in other VRE isolated from both humans and chickens. The results of this study suggest transmission of resistance in enterococci from animals to man. For VRE this might be clonal transmission of animal strains, but transposon transfer seems to occur more commonly.

Agriculture↗
PubMed2003

Multicentre surveillance of antimicrobial resistance in enterococci and staphylococci from Colombian hospitals, 2001-2002.

Invasive isolates of staphylococci and enterococci were collected from 15 tertiary care centres in five Colombian cities from 2001 to 2002. A total of 597 isolates were available for analysis. Identification was confirmed by both automated methods and multiplex PCR assays in a central laboratory. Staphylococcus aureus and coagulase-negative staphylococci (CoNS) corresponded to 49.6% and 29.6% of isolates, respectively, and 20.8% were identified as enterococci. MICs of ampicillin, ciprofloxacin, chloramphenicol, erythromycin, gentamicin, linezolid, oxacillin, rifampicin, teicoplanin, tetracycline, trimethoprim/sulfamethoxazole (SXT) and vancomycin were determined using an agar dilution method as appropriate. Screening for vancomycin-resistant S. aureus was also carried out on brain-heart infusion agar plates supplemented with vancomycin. The presence of mecA and van genes was investigated in methicillin-resistant staphylococci and glycopeptide-resistant enterococci (GRE), respectively. All staphylococci were susceptible to vancomycin, teicoplanin and linezolid. No VISA isolates were found. In S. aureus and CoNS, the lowest rates of resistance were found for SXT (7.4%) and chloramphenicol (10.7%), respectively. Resistance to oxacillin in S. aureus and CoNS was 52% and 73%, respectively. The mecA gene was detected in 97.5% of methicillin-resistant S. aureus isolates. In enterococci, resistance to glycopeptides was 9.7%: vanA (58.3%) and vanB (41.7%) genes were found. Pulsed-field gel electrophoresis indicated that the GRE isolates were closely related. Rates of resistance to ampicillin, ciprofloxacin, chloramphenicol, rifampicin and high levels of gentamicin and streptomycin were 9.7%, 27.4%, 8.9%, 43%, 17% and 28.2%, respectively. All enterococci were susceptible to linezolid.

Anti-Bacterial Agents↗
PubMed1999

Growth inhibition of multiresistant enterococci by interferon-gamma-activated human uro-epithelial cells.

Nosocomial infections with enterococci are an increasing problem in modern medical practice due to the development of resistance to a wide range of antibiotics, including the glycopeptides vancomycin and teicoplanin. An increasing number of vancomycin-resistant enterococci (VRE) have been cultured from clinical specimens -- especially from patients undergoing immunosuppressive therapy -- and bacteraemia caused by these VRE, subsequent to colonisation of epithelial surfaces, is a significant cause of mortality in such patients. Recent evidence showed that the induction of indoleamine 2,3 dioxygenase (IDO) by interferon-gamma (IFN-gamma) inhibited growth of group B streptococci by depleting the essential amino acid L-tryptophan. This study describes the IFN-gamma-induced expression of IDO -- shown at a transcriptional level by Northern blot analysis, at translational level by Western blot and also at a functional level by L-tryptophan degradation to L-kynurenine -- in the uro-epithelial cell line RT4. The depletion of L-tryptophan resulted in growth inhibition of enterococci, and this was confirmed by abrogation of the inhibitory effect by re-supplementation with excess L-tryptophan. Multiresistant enterococci, including vancomycin-resistant strains resistant to all commercially available antibiotics, were inhibited by the IFN-gamma-induced expression of IDO and subsequent L-tryptophan degradation. This may be an important mechanism in the local restriction of colonisation of the urinary tract by endogenous enterococci and in inhibiting the spread of the bacteria beyond the epithelial barrier.

Blotting, Western↗
PubMed1992

Enterococci in human periodontitis.

Enterococci are potential pathogens in many human body sites. This study determined the subgingival occurrence and the in vitro antimicrobial susceptibility of enterococci in 100 persons with early-onset periodontitis and 545 persons with advanced adult periodontitis. Subgingival microbial samples were collected with paper points, transported in VMGA III and plated onto anaerobic enriched brucella blood agar or selective Enterococcosel agar (BBL Microbiology Systems). Enterococcal speciation was performed using commercial micromethod kit systems. In vitro sensitivity was determined using a commercial kit system and an agar dilution assay. Subgingival enterococci occurred in 1% of early-onset periodontitis patients and in approximately 5% of adult periodontitis patients. Enterococcus faecalis was the only enterococcal species recovered, and all but one isolate belonged to the same biotype. In vitro antimicrobial sensitivity testing revealed subgingival enterococci resistant to therapeutic levels of penicillin G, tetracycline, clindamycin and metronidazole, but relatively sensitive to ciprofloxacin and amoxicillin/potassium clavulanate (Augmentin). Enterococci may populate periodontal pockets as superinfecting organisms and, in heavily infected patients, may contribute to periodontal breakdown.

Adult↗
PubMed2006

Bacteriocin production, plasmid content and plasmid location of enterocin P structural gene in enterococci isolated from food sources.

AIMS: To characterize bacteriocin production, antimicrobial spectrum and plasmid content in bacteriocinogenic enterococci from foods. METHODS AND RESULTS: Bacteriocinogenic Enterococcus faecium (14 isolates) and Enterococcus faecalis (three isolates) showed two different patterns of bacteriocin production in liquid broth: exponential-phase and stationary-phase production. Bacteriocin concentrates from all enterococci were inactivated by trypsin, but seldom by heat (100-117 degrees C), extremes of pH (2.0 to 9.0) or reducing agents (such as dithiothreitol). All bacteriocin concentrates were active against Listeria innocua and Listeria monocytogenes, and most were also active against many Ent. faecalis and Ent. faecium isolates. Enterococci clustered in three main groups according to their plasmid content (which included plasmids from 2.0 to 53 kb). Several isolates from different foods showed almost identical plasmid profiles. The enterocin P structural gene (entP) was detected by hybridization on plasmids of c. 19, 26 and/or 35-38 kb. CONCLUSIONS: Enterococci from food show different patterns of bacteriocin production and different plasmid content in spite of carrying similar bacteriocin-encoding genes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides information on the diversity of bacteriocinogenic enterococci from food sources carrying apparently similar enterocin genes.

Bacteriocins↗
PubMed1998

Prospective case-cohort study of intestinal colonization with enterococci that produce extracellular superoxide and the risk for colorectal adenomas or cancer.

OBJECTIVE: The aim of this study was to determine whether intestinal colonization with enterococci that produce extracellular superoxide (O2*-), a free radical implicated in the development of colorectal cancer, is associated with these lesions or their precursors. METHODS: A prospective case-cohort study was performed by isolating enterococci from stools of consecutive patients undergoing colonoscopy who had no prior history of colonoscopy or colorectal cancer. A food frequency questionnaire was also administered to control for dietary factors known to affect the risk for these lesions. RESULTS: Among 159 evaluable participants were 77 with no precancerous or cancerous pathology, 61 with adenomas <2 cm, 10 with adenomas > or =2 cm, and 11 with cancer. Regression analyses found no associations for those subjects with adenomas of any size or with cancer and colonization with O2*--producing enterococci, any nutrient, or age. For those patients with large adenomas > or = 2 cm or cancer, however, significant associations were noted for age (OR 1.94 per decade, 95% CI 1.2-3.5), beta-carotene (OR 0.44 per 500 microg/1000 kcal/day, 95% CI 0.2-0.8), vitamin A (OR 3.20 per 500 microg/1000 kcal/day, 95% CI 1.2-8.9), and vitamin E (OR 0.09 per 10 mg/ 1000 kcal/day, 95% CI 0.006-0.9), but not colonization with O2*--producing enterococci. Second stools collected 1 yr later, however, often contained dissimilar enterococcal flora, undermining an important study assumption. CONCLUSIONS: Significant associations were found for those with large adenomas or cancer (but not small adenomas), with age, and with foods enriched for vitamin A, vitamin E, and beta-carotene. An association between colonization with O2*--producing enterococci and colorectal adenomas or cancer, however, could not be ascertained, possibly because intestinal enterococcal flora changes over time, leaving a potentially cohesive hypothesis of colon cancer and risk factors as yet unanswered.

Adenoma↗
PubMed1995

[Drug sensitivity and expression of beta-lactamase in enterococci isolated at Okayama University Hospital].

The following results were obtained from a study of Enterococci isolated at the Okayama University Hospital from 1990 to 1994. 1) The isolation frequency of Enterococci was about 6% for each year. 2) The percentage of Enterococcus faecalis (E. faecalis) among Enterococci decreased each year, but the percentage of Enterococcus faecium (E. faecium), and Enterococcus avium (E. avium) increased each year. 3) Results of drug sensitivity tests revealed that the incidence of ofloxacin (OFLX) resistant E. faecalis and E. avium increased each year. Also, the resistance of E. faecalis to ampicillin (ABPC), the primary medication choice for treating E. faecalis, increased each year. 4) A few vancomycin (VCM) non-sensitive Enterococci were isolated. These bacteria showed low-sensitivity toward ABPC, imipenem (IPM), gentamicin (GM), and OFLX, and the extent of multiple drug resistance increased each year. 5) One hundred strains of Enterococci were selected to examine the expression of beta-lactamase using the broth method and the iodine-starch method. However, beta-lactamase producing strains were not detected.

Anti-Bacterial Agents↗
PubMed1992

Emergence and nosocomial transmission of ampicillin-resistant enterococci.

Between 1986 and 1988, the incidence of ampicillin-resistant enterococci increased sevenfold at a university-affiliated hospital. Forty-three patients acquired nosocomial infections with ampicillin-resistant enterococci, most of which were also resistant to mezlocillin, piperacillin, and imipenem. An analysis of plasmid and chromosomal DNAs of isolates revealed that the increase was due to an epidemic of 19 nosocomial infections that yielded closely related strains of Enterococcus faecium and to a significant increase in the incidence of nonepidemic, largely unrelated strains of ampicillin-resistant enterococci. The nonepidemic strains were identified as E. faecium, E. raffinosus, E. durans, and E. gallinarum. A logistic regression analysis revealed that patients with nonepidemic resistant strains were 16 times more likely than controls to have received preceding therapy with imipenem. In our institution, the increase in the incidence of ampicillin-resistant enterococci appears to be due to the selection of various strains of resistant enterococci by the use of imipenem and to the nosocomial transmission of E. faecium and E. raffinosus.

Adult↗
PubMed1998

A rapid, specific membrane filtration procedure for enumeration of enterococci in recreational water.

A two-step membrane filter (MF) method with mE medium, upon which the membrane must be incubated for 48 h and then transferred to a substrate medium to differentiate enterococci, is recommended by the U.S. Environmental Protection Agency to measure enterococci in fresh and marine recreational waters. The original mE medium was modified by reducing the triphenyltetrazolium chloride from 0.15 to 0.02 g/liter and adding 0.75 g of indoxyl beta-D-glucoside per liter. The new MF medium, mEI medium, detected levels of enterococci in 24 h comparable to those detected by the original mE medium in 48 h, with the same level of statistical confidence. In addition, the use of mEI medium eliminated the need to transfer the membrane to a substrate medium to differentiate enterococci from other genera of the fecal streptococcal group. Colonies from mEI medium were examined to determine the rates of false-positive and false-negative occurrences. mEI medium had a false-positive rate of 6.0% and a false-negative rate of 6.5%. Interlaboratory testing of the MF method with mEI medium demonstrated that the relative reproducibility standard deviations among laboratories ranged from 2.2% for marine water to 18.9% for freshwater. The comparative recovery studies, specificity determinations, and multilaboratory evaluation indicated that mEI medium has analytical performance characteristics equivalent to those of mE medium. The simplicity of use and decreased incubation time with mEI medium will facilitate the detection and quantification of enterococci in fresh and marine recreational waters.

Culture Media↗
PubMed1963

Occurrence of enterococci on plants in a wild environment.

Enterococci were obtained from 14% of nearly 2,200 flowers, 3.4% of non-floral structures of angiosperms, and from 8.3% of samples of soil, water, and lesser plants of the Great Smoky Mountains National Park, an area little influenced by the presence of man. The enterococci were recovered from one or more flowers or flower clusters of 1,515 samples in 47 taxa, but not from flowers of 67 taxa with 654 samples. The per cent of recovery was influenced adversely by dense forest cover and by increase in elevation, as compared with recovery from flowers in sunny locations in the lower elevations. The per cent recovery increased directly with rising seasonal temperature, with the maximal per cent of recovery occurring in September. In no instance did all samples of a species of flower or plant yield enterococci on culture, and with only three genera, Cacalia, Delphinium, and Mitchella, were the bacteria obtained from more than 50% of the samples. Approximately 11% of the cultures isolated were identified as Streptococcus faecalis, 64% as the soft curd producing, caseolytic variant of S. faecalis, 4% as S. faecalis var. zymogenes, and 20% as S. faecium. The per cent distribution of these species on plants was reasonably similar to the distribution within wild animals in the same environment. It was concluded that the enterococci occurring on plants arise commonly from the wild animals, and that they do not represent plant-specific species or variants of the enterococci.

Animals↗
PubMed1995

Evaluation of a modified nitrous acid extraction latex agglutination kit for grouping beta-hemolytic streptococci and enterococci.

The rapid and accurate identification of the Lancefield group of beta-hemolytic streptococci and enterococci is an important procedure in clinical laboratories. Latex agglutination techniques are more rapid and technically less demanding than traditional extraction-precipitation methods. Prolex (Pro-Lab Diagnostics, Richmond Hill, Ontario, Canada) is a latex agglutination kit which contains modified nitrous acid reagents to extract antigens and can be used to detect group D antigen in streptococci and enterococci, as well as group A, B, C, F, and G antigens. A total of 302 strains of streptococci and enterococci were tested with this kit. All streptococci of groups A (41 strains), B (39 strains), C (35 strains), D (3 strains), F (10 strains), and G (48 strains) were correctly grouped, as were 125 (97%) of 129 strains of enterococci. Prolex is a reliable method for grouping the beta-hemolytic streptococci and enterococci most frequently encountered in clinical laboratories.

Antigens, Bacterial↗
PubMed2006

Validation of VITEK 2 version 4.01 software for detection, identification, and classification of glycopeptide-resistant enterococci.

We evaluated the ability of the new VITEK 2 version 4.01 software to identify and detect glycopeptide-resistant enterococci compared to that of the reference broth microdilution method and to classify them into the vanA, vanB, vanC1, and vanC2 genotypes. Moreover, the accuracy of antimicrobial susceptibility testing with agents with improved potencies against glycopeptide-resistant enterococci was determined. A total of 121 enterococci were investigated. The new VITEK 2 software was able to identify 114 (94.2%) enterococcal strains correctly to the species level and to classify 119 (98.3%) enterococci correctly to the glycopeptide resistance genotype level. One Enterococcus casseliflavus strain and six Enterococcus faecium vanA strains with low-level resistance to vancomycin were identified with low discrimination, requiring additional tests. One of the vanA strains was misclassified as the vanB type, and one glycopeptide-susceptible E. facium wild type was misclassified as the vanA type. The overall essential agreements for antimicrobial susceptibility testing results were 94.2% for vancomycin, 95.9% for teicoplanin, 100% for quinupristin-dalfopristin and moxifloxacin, and 97.5% for linezolid. The rates of minor errors were 9% for teicoplanin and 5% for the other antibiotic agents. The identification and susceptibility data were produced within 4 h to 6 h 30 min and 8 h 15 min to 12 h 15 min. In conclusion, use of VITEK 2 version 4.01 software appears to be a reliable method for the identification and detection of glycopeptide-resistant enterococci as well as an improvement over the use of the former VITEK 2 database. However, a significant reduction in the detection time would be desirable.

Anti-Bacterial Agents↗
PubMed2005

Biofilm formation and esp gene carriage in enterococci.

AIMS: To investigate biofilm production and esp carriage in enterococci. METHODS: Biofilm production in vancomycin resistant enterococci (VRE) and vancomycin susceptible enterococci (VSE) was tested on a microtitre plate method, using both brain heart infusion (BHI) broth and human serum as media. Isolates were screened for the esp gene, which has been reported to be essential for biofilm formation in enterococci, by means of the polymerase chain reaction. RESULTS: None of seven VRE and nine of 28 VSE tested formed a biofilm. One initially negative VRE Enterococcus faecium isolate produced a strong biofilm after 21 weeks of dry starvation on a cotton swab. By Fisher's exact test, there was no significant difference in biofilm formation between VRE and VSE, E faecalis and E faecium, or isolates from different sites. Biofilm formation was independent of possession of the esp gene. One isolate produced a strong biofilm in human serum but only a weak biofilm in BHI, whereas another produced a moderate biofilm in human serum but a weak biofilm in BHI. CONCLUSIONS: The acquisition of vancomycin resistance may result in a lower ability to form biofilms, but a larger study using clinical isolates is needed to test this hypothesis. That one initially negative VRE isolate produced a strong biofilm after prolonged dry starvation suggests that biofilm formation may be an adaptive response. The esp gene does not appear to be necessary or sufficient for production of biofilms in enterococci.

Bacterial Proteins↗
PubMed2005

Occurrence and growth characteristics of Escherichia coli and enterococci within the accumulated fluid of the northern pitcher plant (Sarracenia purpurea L.).

Sarracenia purpurea L., a carnivorous bog plant (also known as the pitcher plant), represents an excellent model of a well-defined, self-contained ecosystem; the individual pitchers of the plant serve as a microhabitat for a variety of micro- and macro-organisms. Previously, fecal indicator bacteria (Escherichia coli and enterococci) were shown as incidental contaminants in pitcher fluid; however, whether their occurrence in pitcher fluid is incidental or common has not been established. The purpose of this study was to investigate the occurrence, distribution, and growth potential of E. coli and enterococci in pitcher plant fluid from a protected bog in northwest Indiana. Escherichia coli and enterococci were recovered in pitcher fluids (n=43 plants), with mean densities (log CFU mL-1) of 1.28+/-0.23 and 1.97+/-0.27, respectively. In vitro experiments showed that E. coli growth in fluid not containing insects or indigenous organisms was directly proportional to the fluid concentration (growth was 10-fold in 24 h in 100% fluid); however, in the presence of other indigenous organisms, E. coli and enterococci were only sustained for 5 days at 26 degrees C. Pulsed-field gel electrophoresis (PFGE) analysis showed that the plant Enterococcus faecalis isolates were genetically distinct from the human isolates; identical PFGE patterns were observed among plant isolates that fell into one of six clonal groups. These findings suggest that (i) E. coli and enterococci occurrence in pitcher plants is rather common in the bog studied, although their originating source is unclear, and (ii) the pitcher fluid contains adequate nutrients, especially carbon and energy sources, to promote the growth of indicator bacteria; however, under natural conditions, the biotic factors (e.g., competition for nutrients) may restrict their growth.

DNA, Bacterial↗
PubMedDate not supplied

[Evaluation of antimicrobial sensitivity of 87 clinical isolates of vancomycin-resistant enterococci].

OBJECTIVES: 1) To evaluate the antimicrobial susceptibility pattern of vancomycin-resistant enterococci to the antimicrobial agents that are commonly used to treat enterococci infections and to some alternative drugs. 2) To evaluate the accuracy of E test for susceptibility testing enterococci. MATERIAL AND METHOD: We evaluated 87 clinical VRE isolates that were selected from a previous study which analyzed 1936 clinical isolates collected and processed in 97 US medical centers in the last quarter of 1992. The isolates were identified to the species level by using the API 20S System, the Vitek gram-positive identification cards and a modified version of the conventional method proposed by Facklam and Collins. The in vitro susceptibility testing was performed by broth microdilution, E test and disk diffusion methods, following the criteria described by the National Committee for Clinical Laboratory Standards (NCCLS). The VRE isolates were tested against antimicrobial agents commonly used to treat enterococci infections (vancomycin, teicoplanin, ampicillin, penicillin, gentamicin and streptomycin) and against ten potential alternative drugs (chloramphenicol, doxycycline, sparfloxacin, ciprofloxacin, clinafloxacin, erythromycin, spectinomycin, trospectomycin, trimetoprim-sulfametoxazol and novobiocin). RESULTS: Our results showed a high rate of resistance to ampicillin and penicillin (86%). High level resistance to gentamicin and streptomycin was demonstrated by 82% and 85% respectively. Although teicoplanin and vancomycin belong to the same antibiotic group (glycopeptide), 29% of VRE were susceptible to teicoplanin. Among the alternative drugs, trospectomycin, doxycyclin and chloramphenicol showed the highest in vitro activity, with 94%, 92% and 82% susceptibility respectively. In addition, erythromycin, trimetoprim-sulfametoxazol and ciprofloxacin showed the highest rates of resistance (98%, 83% and 69%, respectively). CONCLUSION: The treatment options for infections caused by vancomycin-resistant enterococci seem to be very narrow since a small percentage of those isolates were susceptible to the other antimicrobial agents commonly used to treat these infections and only a few of the alternative drugs tested showed good in vitro activity. Many regimens using various antibiotic combinations have been tested against VRE, most of them with fluoroquinolones. However further studies are necessary to evaluate the clinical role of these antibiotic combinations.

Anti-Bacterial Agents↗
PubMed2002

The effect of pH on enterococci removal in Pistia-, duckweed- and algae-based stabilization ponds for domestic wastewater treatment.

A batch scale experiment was conducted to determine the effect of pH on enterococci die-off. A continuous flow system was also established to determine the environmental conditions and their effects on enterococci removal. The batch experiment was conducted for pHs: 4, 5, 7, 9, and 11 under light and dark conditions. Enterococci and DO were measured every day and every other day respectively for nine days. Pathogen removal rates at pH 4, 5, 7, 9 and 11 in the light/dark were (expressed as d(-1)) -2.1/-2.1, -2.1/-1.5, -2.1/-1.5, -2.1/-1.4 and -1.1/-1.0, respectively. DO levels were low, between 0.17 mg/L at pH 4 (light) to 0.56 mg/L at pH 7 (light). The continuous flow system consisted of Pistia (water lettuce), duckweed and algal treatments in series of four ponds with a total retention period of 28 days after two days of anaerobic pre-treatment. After two months of operation, temperature, pH, DO, TDS, and enterococci populations were monitored. A low pH of 4.4 was obtained in the Pistia ponds. Neutral conditions were observed in the duckweed system, while pH values >9 were observed in the algal system. Enterococci decreased from 7.8 x 10(6) to <500/100 ml in all treatment systems after 28 days of treatment with no significant differences between treatments.

Enterococcus↗