Vancomycin-sensitive Enterococcus Faecalis Research Articles

New Frontier on Antimicrobial Therapy: Long-Acting Lipoglycopeptides.

Long-acting lipoglycopeptides (LGPs), such as dalbavancin and oritavancin, are semisynthetic antibiotics known for their strong effectiveness against a wide array of Gram-positive bacteria. This includes Staphylococcus aureus, both methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) strains, coagulase-negative Staphylococci (CoNS), streptococci, and vancomycin-sensitive Enterococcus faecalis. A literature search was conducted on PubMed and on ClinicalTrials.gov to identify articles published until July 2023 investigating the use of oritavancin and dalbavancin in clinical practice. The review included case reports, case series, observational studies, and clinical studies. Although more consistent data are needed, LGPs seem to be a good alternative that may provide a quicker hospital discharge and reduce long-term intravenous access and therapy. This is attributed to their unique pharmacologic and pharmacokinetic characteristics. More quality data (i.e., number of patients treated with clinical success) are needed before clinicians may use these therapies more widely.

Vancomycin-sensitive Enterococcus faecium bacteraemia - hospital transmission and mortality in a Danish University Hospital.

Introduction. The emergence of vancomycin-resistant Enterococcus faecium (VREfm) has left the vancomycin-sensitive E. faecium (VSEfm) strains almost unnoticed.Hypothesis. Molecular characteristics, hospital transmission patterns and clinical impact of VSEfm have changed, and VSEfm is a predictor of VREfm introduction.Aim. We wanted to do a molecular characterization of VSEfm to identify hospital transmissions and links between VSEfm and VREfm, and to investigate the demographics, treatment and impact on mortality of VSEfm bacteraemia.Methodology. VSEfm and VREfm blood culture isolates from Odense University Hospital, Denmark, from 2015 to 2019 were characterized using whole-genome sequencing and core-genome multilocus sequence typing (cgMLST). Clonal shifts and diversity of the VREfm isolates were compared to the VSEfm isolates. Hospital records were used for clinical data and transmission investigation of VSEfm cases.Results. Six-hundred and thirty VSEfm isolates from 599 patients belonged to 42 sequence types (STs) and 131 complex types (CTs) in several clusters. Multiple types were involved in putative transmission, occurring over the entire period. Twenty-seven VREfm bacteraemia cases were included. No correlation between the VSEfm and VREfm clones was identified. The 30 day mortality was 40 %, but only in 6.3 % of the cases, VSEfm bacteraemia was the likely cause of death.Conclusion. The molecular types of VSEfm bacteraemia isolates are changing and diverse. No direct correlation between VSEfm and the introduction of VREfm was found, but widespread hospital transmission indicates a presence of risk factors that could facilitate transmission of other micro-organisms as well. VSEfm bacteraemia is rarely the cause of death, indicating that 30 day mortality does not reflect the cause of death.

Prevalence, Microbiological Profile, and Risk Factors of Surgical Site Infections in Saudi Patients with Colorectal Cancer.

Resection surgery in patients with colorectal cancer (CRC) patients is associated with potential complications, including surgical site infection (SSI). To estimate the prevalence rate of SSI, identify the common pathogens responsible for SSI, and determine potential risk factors for SSI development in a cohort from Saudi Arabia. Patients with CRC who underwent bowel resection surgery at King Abdulaziz Medical City, Riyadh, between January 01, 2016, and December 31, 2019, were retrospectively included. Demographics, comorbidities, surgical procedure data, and the results of preoperative laboratory tests were retrospectively collected from medical records through the health information system. The study population was divided into two groups: those who developed SSI and those who did not. A total of 92 patients with CRC who underwent resection surgery were included, of which 54 (58.7%) were males. The median age was 65 (IQR 55.5-75.0) years. SSI was observed in 25 (27.2%) patients. The most frequently isolated organisms were Escherichia coli and Pseudomonas aeruginosa, followed by Klebsiella pneumoniae, vancomycin-sensitive Enterococcus faecium, and methicillin-resistant Staphylococcus aureus. Three E. coli isolates were producers of extended-spectrum beta-lactamases, and two K. pneumoniae isolates exhibited a multidrug resistance profile. Low preoperative serum albumin level was identified as a significant independent risk factor for developing SSI (AOR = 0.853, 95% CI = 0.748-0.973, P = 0.0181). The study found a notable prevalence of SSI among the included patients. Gram-negative bacteria were more involved in SSI events and were also associated with drug-resistance patterns. Gut microbiota bacteria were most commonly involved in SSIs. Low preoperative serum albumin levels predicted the development of postoperative SSI, and thus its close monitoring and management before surgery could reduce the SSIs.

Streptomyces thinghirensis sp. nov. as a promising path for green synthesis of silver nanoparticles: High eradication of multidrug-resistant bacteria and catalytic activity

Biological and non-biological pollutants are posing a major health and environmental threat worldwide. For this reason, we reported on the synthesis and investigations of the silver nanoparticle (ST-AgNPs), using Streptomyces thinghirensis sp. (ST) as an original Streptomyces species deposited in GenBank under the accession number DSM 41919 T. Various techniques such as UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, particle-size analyzer, scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) for the characterization of the structure and morphology of biosynthesized ST-AgNPs, thereby, the evaluation of their catalyst and antimicrobial behaviors. ST-AgNPs nanoparticles are spherical, crystallizing with a size ranging from 10 to 30 nm, and are stable (−27.2 mV). They were able to reduce 4-nitrophenol to 4-aminophenol within 15 min. ST-AgNPs exhibited excellent antibacterial activities against Vancomycin-resistant Enterococcus faecium ATCC 700221vanA, Cefoxitin-resistant Staphylococcus aureus NCTC 12493 and Ceftazidime-resistant Pseudomonas aeruginosa ATCC BAA-2108, as well as Vancomycin-sensitive Enterococcus faecalis ATCC 29212, Cefoxitin-sensitive Staphylococcus aureus ATCC 29213 and Ceftazidime-sensitive Pseudomonas aeruginosa ATCC 27853, with the minimal inhibitory concentration ranging from 3.125 to 12.5 µg/mL. In conclusion the green synthesis approaches using ST would be the most important path in biomaterial sciences, which enrich their biological, medical and pharmaceutical applications.

Isolation and characterization of new phenolic siderophores with antimicrobial properties from Pseudomonas sp. UIAU-6B.

Five new phenolic siderophores 1–5 were isolated from the organic extract of a culture broth in a modified SGG medium of Pseudomonas sp. UIAU-6B, obtained from sediments collected from the Oyun river in North Central Nigeria. The structure of the new compounds, pseudomonin A–C (1–3) and pseudomobactin A and B (4 and 5) isolated alongside two known compounds, pseudomonine (6) and salicylic acid (7), were elucidated based on high-resolution mass spectrometry, 1D and 2D NMR analyses. The absolute configuration of the threonine residue in compounds 1–5 was determined by Marfey analysis. The antimicrobial evaluation of compound 4 exhibited the most potent activity against vancomycin-sensitive Enterococcus faecium VS144754, followed by 3 and 5, with MIC values ranging from 8 to 32 µg/mL. Compounds 2 and 3 exhibited moderate activity against Mycobacterium tuberculosis H37Rv, with MIC values of 7.8 and 15.6 µg/mL, respectively. Plausible biosynthetic hypotheses toward the new compounds 1–5 were proposed.

Effect of Vancomycin on Cytoplasmic Peptidoglycan Intermediates and van Operon mRNA Levels in VanA-Type Vancomycin-Resistant Enterococcus faecium.

Resistance in VanA-type vancomycin-resistant Enterococcus faecium (VREfm) is due to an inducible gene cassette encoding seven proteins (vanRSHAXYZ). This provides for an alternative peptidoglycan (PG) biosynthesis pathway whereby D-Ala-D-Ala is replaced by D-Ala-d-lactate (Lac), to which vancomycin cannot bind effectively. This study aimed to quantify cytoplasmic levels of normal and alternative pathway PG intermediates in VanA-type VREfm by liquid chromatography-tandem mass spectrometry before and after vancomycin exposure and to correlate these changes with changes in vanA operon mRNA levels measured by real-time quantitative PCR (RT-qPCR). Normal pathway intermediates predominated in the absence of vancomycin, with low levels of alternative pathway intermediates. Extended (18-h) vancomycin exposure resulted in a mixture of the terminal normal (UDP-N-acetylmuramic acid [NAM]-l-Ala-D-Glu-l-Lys-D-Ala-D-Ala [UDP-Penta]) and alternative (UDP-NAM-l-Ala-γ-D-Glu-l-Lys-D-Ala-D-Lac [UDP-Pentadepsi]) pathway intermediates (2:3 ratio). Time course analyses revealed normal pathway intermediates responding rapidly (peaking in 3 to 10 min) and alternative pathway intermediates responding more slowly (peaking in 15 to 45 min). RT-qPCR demonstrated that vanA operon mRNA transcript levels increased rapidly after exposure, reaching maximal levels in 15 min. To resolve the effect of increased van operon protein expression on PG metabolite levels, linezolid was used to block protein biosynthesis. Surprisingly, linezolid dramatically reduced PG intermediate levels when used alone. When used in combination with vancomycin, linezolid only modestly reduced alternative UDP-linked PG intermediate levels, indicating substantial alternative pathway presence before vancomycin exposure. Comparison of PG intermediate levels between VREfm, vancomycin-sensitive Enterococcus faecium, and methicillin-resistant Staphylococcus aureus after vancomycin exposure demonstrated substantial differences between S. aureus and E. faecium PG biosynthesis pathways. IMPORTANCE VREfm is highly resistant to vancomycin due to the presence of a vancomycin resistance gene cassette. Exposure to vancomycin induces the expression of genes in this cassette, which encode enzymes that provide for an alternative PG biosynthesis pathway. In VanA-type resistance, these alternative pathway enzymes replace the D-Ala-D-Ala terminus of normal PG intermediates with D-Ala-D-Lac terminated intermediates, to which vancomycin cannot bind. While the general features of this resistance mechanism are well known, the details of the choreography between vancomycin exposure, vanA gene induction, and changes in the normal and alternative pathway intermediate levels have not been described previously. This study comprehensively explores how VREfm responds to vancomycin exposure at the mRNA and PG intermediate levels.

Unravelling the benefits and barriers to utilising whole-genome sequencing in the investigation of outbreaks

Background This prospective study was established to develop and evaluate methods to harness pathogen sequencing in the clinical microbiology environment. We describe new insights into the clinical benefits of using whole-genome sequencing (WGS) for outbreak investigation with solutions for the practical barriers to implementation in clinical settings. Methods Surveillance software (ICNet) and statistical process control charts (SPCs) detected potential outbreaks of meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), carbapenem-resistant Enterobacteriaceae (CRE), Enterobacteriaceae producing extended spectrum β-lactamases (ESBLs), Listeriaspp. and optrAgene positive enterococci. Isolates were sent to reference laboratories for conventional typing and the Infection Group, School of Medicine, University of St Andrews for WGS (Illumina Inc, San Diego, CA, USA) and bioinformatic data analysis. Results Over 400 isolates have been sequenced to date. WGS replaced multiple typing techniques in a Pseudomonas aeruginosa ICU outbreak. It confirmed two patient’s Listeria spp. isolates were indistinguishable prompting hospital kitchen inspections, identified a patient to be carrying two strains of VRE and confirmed that vancomycin-sensitive Enterococcus faecium isolates related to a VRE cluster. We observed five main barriers to implementing WGS (infrastructure, performance/quality assessment of data, isolate selection, clinical result interpretation and database management). Conclusion WGS is beneficial in outbreaks of uncommon organisms and when conventional typing cannot show whether isolates are linked or not. Identifying barriers assisted us in developing a clinical decision aid that can be used by clinicians when applying WGS to outbreak investigations.

A nonclonal outbreak of vancomycin-sensitive Enterococcus faecalis bacteremia in a neonatal intensive care unit.

To describe an outbreak of bacteremia caused by vancomycin-sensitive Enterococcus faecalis (VSEfe). An investigation by retrospective case control and molecular typing by whole-genome sequencing (WGS). A tertiary-care neonatal unit in Melbourne, Australia. Risk factors for 30 consecutive neonates with VSEfe bacteremia from June 2011 to December 2014 were analyzed using a case control study. Controls were neonates matched for gestational age, birth weight, and year of birth. Isolates were typed using WGS, and multilocus sequence typing (MLST) was determined. Bacteremia for case patients occurred at a median time after delivery of 23.5 days (interquartile range, 14.9-35.8). Previous described risk factors for nosocomial bacteremia did not contribute to excess risk for VSEfe. WGS typing results designated 43% ST179 as well as 14 other sequence types, indicating a polyclonal outbreak. A multimodal intervention that included education, insertion checklists, guidelines on maintenance and access of central lines, adjustments to the late onset sepsis antibiotic treatment, and the introduction of diaper bags for disposal of soiled diapers after being handled inside the bed, led to termination of the outbreak. Typing using WGS identified this outbreak as predominately nonclonal and therefore not due to cross transmission. A multimodal approach was then sought to reduce the incidence of VSEfe bacteremia.

Assessment of vancomycin resistance transfer among enterococci of clinical importance in milk matrix

Dissemination of vancomycin resistance in enterococci has been associated with horizontal transfer of mobile genetic elements. Aim of the study was to evaluate if milk matrix is a suitable environment to support transferability of vancomycin resistance (vanA) gene from clinical vancomycin-resistant Enterococcus faecium to vancomycin-sensitive Enterococcus faecalis. Enterococci strains were firstly screened for the presence of cpd (inducible sex pheromone determinant) gene, vanA and tetL genes (vancomycin and tetracycline resistance markers, respectively) and the gelE (extracellular metalloendopeptidase) gene to define the mating pairs. Based on these selection markers, we investigated the transferability of eight plasmid-borne vanA harbored by E. faecium (vanA+, cpd-, tetL- and gelE-) into two E. faecalis (vanA-, cpd+, tetL + and gelE+) recipient strains in milk matrix. The strains were mated in a 1:1 ratio in 7% reconstituted milk and incubated at 37 °C. Transconjugants emerged from all 16 matings within 2 h of incubation and were evidenced by dual antibiotic resistance (vancomycin and tetracycline). The vancomycin-resistance of trasconjugants was maintained even after ten subsequent passages on nonselective medium. Transconjugants were positive for vanA, tetL and gelE genes. This study indicates milk matrix as suitable environment to support gene exchange between Enterococcus species.

Susceptibility of vancomycin-resistant and -sensitive Enterococcus faecium obtained from Danish hospitals to benzalkonium chloride, chlorhexidine and hydrogen peroxide biocides.

In Danish hospitals, the number of infections caused by vancomycin-resistant Enterococcus faecium (VRE faecium) has dramatically increased in recent years. Hospital disinfectants are essential in eliminating pathogenic microorganisms, and reduced susceptibility may contribute to hospital-associated infections. We have addressed whether clinical VRE faecium display decreased biocide susceptibility when compared to vancomycin-sensitive Enterococcus faecium (VSE faecium) isolates. In total 12 VSE faecium and 37 VRE faecium isolates obtained from Danish hospitals over an extended time period were tested for susceptibility towards three commonly applied biocides, namely benzalkonium chloride, chlorhexidine and hydrogen peroxide. For benzalkonium chloride, 89 % of VRE faecium strains had a minimal inhibitory concentration (MIC) of 8 mg l-1, whereas for VSE faecium, only 25 % of the strains had an MIC of 8 mg l-1. For chlorhexidine, the MIC of 95 % of VRE faecium strains was 4 mg l-1 or higher, while only 33 % of VSE faecium strains displayed MIC values at the same level. In contrast, both VRE and VSE faecium displayed equal susceptibility to hydrogen peroxide, but a higher minimal bactericidal concentration (MBC) was found for the former. The efflux activity was also assessed, and this was generally higher for the VRE faecium strains compared to VSE faecium. VRE faecium from Danish hospitals demonstrated decreased susceptibility towards benzalkonium chloride and chlorhexidine compared to VSE faecium, where the use of chlorhexidine is particularly heavy in the hospital environment. These findings suggest that biocide tolerance may characterize VRE faecium isolated in Danish hospitals.

Critical concentrations of surfactant combination regimens with MTAD™ on vancomycin-sensitive Enterococcus faecalis

Background: Enterococcus faecalis is an opportunistic pathogen with greater virulence traits and has gained significance in endodontic literature. It is resistant to most irrigants and medicaments with significant posttreatment reversal cultures. The purpose of this study was to evaluate the critical concentrations of irrigants and surfactants and the possible outcome of the combination regimen on E. faecalis. Methods: Five percent sodium hypochlorite (NaOCl), chlorhexidine (CHX), iodine potassium iodide (IKI), and surfactants such as cetrimide (CTR) and sodium dodecyl sulfate (SDS) were prepared. BioPure™ MTAD™ served as control. Minimum inhibitory concentration was performed to determine the dilution fold and dilution factor by serial dilution, followed by minimum bactericidal concentration on agar plates. Results: Although CHX performed better than MTAD™, it proved to be bacteriostatic in action at lower concentrations. NaOCl and IKI were found to be inferior and were excluded. CTR was found to be better than MTAD™; while SDS showed insignificant results. The combination surfactant regimens (CHX + CTR; CHX + SDS) performed in a synergistic fashion and achieved higher eradication rates. Bactericidal action with narrow margins between critical concentrations was recorded and found to be superior to any test irrigant, including MTAD™. Conclusion: Critical concentrations of surfactant combination regimens were found to be highly effective at lower dilutions on E. faecalis. This combination can overcome the limitations, potentiate antimicrobial spectrum, and increase the substantive antimicrobial action of CHX application in clinical endodontics.

Peritonitis in a continuous ambulatory peritoneal dialysis patient by two different species of enterococci: A rare finding

Peritonitis in a continuous ambulatory peritoneal dialysis patient by two different species of enterococci is a rare condition. We report a case of peritonitis from which vancomycin sensitive Enterococcus faecalis and vancomycin resistant Enterococcusc faecium were isolated. It also emphasizes the effectiveness of linezolid for the treatment of vancomycin resistant enterococcal infection.

Performance of CHROMagar VRE Medium for the Detection of Airborne Vancomycin-Resistant/SensitiveEnterococcusSpecies

Vancomycin-sensitive and vancomycin-resistant Enterococcus (VSE and VRE) species have become a significant health problem. CHROMagar medium, which permits direct, color-based identification of target pathogens, could potentially be used to rapidly monitor airborne VSE and VRE. In this study, the efficiency of CHROMagar VRE medium without vancomycin supplementation (CVSE) for collecting airborne vancomycin-sensitive Enterococcus faecalis was evaluated in a chamber study. Subsequently, the performance of bioaerosol samplers combined with CVSE and CHROMagar VRE (CVRE) was evaluated in a hospital environment, a wastewater treatment plant, and a pig-rearing facility. Our results demonstrated that an Andersen impactor was much more effective than a Nuclepore filter for collecting airborne E. faecalis at relative humidity levels of 30% and 55%. In addition, approximately 10% of the isolated environmental Enterococcus strains were vancomycin-resistant. The average sensitivity, specificity, positive predictive val...

Antibacterial activity and mutagenicity of leaves of <i>Indigofera tinctoria</i> Linn

Objective: Indigofera tinctoria Linn was traditionally been used in the ancient herbal medicine in India/China for epilepsy, nervous disorders, bronchitis, and liver ailments; and also used as an anticardiovascular, but there was no literature evidence substantiating its antibacterial activity. The purpose of this study is to determine the antibacterial and mutagenic properties of an extract prepared from the leaves of I.tinctoria, commonly known as indigo plant. Methods: Minimum inhibitory concentrations (MICs) of the extract are determined with respect to bacterial species by agar dilution as per Clincial and Laboratory Standard Institute and mutagenicity of the extract is determined by Ames test. Results: The respective MICs of the methanol extract of I.tinctoria were methicillin sensitive Staphylococcus aureus 0.125 µg/ml, methicillin resistant S.aureus 0.25 µg/ml, coagulase negative S.aureus 0.25-0.5 µg/ml, vancomycin sensitive Enterococcus faecalis 0.5 µg/ml, vancomycin resistant Enterococcus species 0.125-0.5 µg/ml, Moraxella 2 µg/ml, Streptococcus species 0.125-0.25 µg/ml, Haemophilus influenzae 2-4 µg/ml and against anaerobes is 1-2 µg/ml. Time kill assay were analyzed for methanol extract of I.tinctoria and it showed bacteriostatic and nonmutagenic activity up to 5 mg per plate in Ames test both in the presence and absence of S9 fraction. Conclusion: Methanol extract of I.tinctoria exhibited antibacterial activity, which was more active than that of standard linezolid, against a variety of clinically important bacteria isolated from near by selected hospitals in India and was found to be nonmutagenic up to 5 mg/plate in Ames test.

Enhancement of Vancomycin Activity by Phenothiazines against Vancomycin‐Resistant Enterococcus Faecium in vitro

The antimicrobial and resistance-reversal activities of seven phenothiazine derivatives were evaluated against vancomycin-sensitive Enterococcus faecalis ATCC 29212, vancomycin resistant E. faecalis ATCC 51299 and ten vancomycin-resistant E. faecium strains originating from human infections. Minimum inhibitory concentrations (MIC) of the compounds were determined by agar dilution method, and synergy between phenothiazines and vancomycin was investigated using Checkerboard (microbroth dilution) technique. We found that all enterococci strains, regardless of their susceptibility to vancomycin, were inhibited by phenothiazines at concentrations varying from 8 to 256 microg/ml, with thiethylperazine being the most potent inhibitory agent. Besides, all the phenothiazines showed partial synergy with vancomycin and could lessen MIC of vancomycin from 512 to 8 microg/ml at their sub-inhibitory concentrations. The highest reduction in MIC was observed with chlorpromazine (32 times); however, thiethylperazine and promethazine stood next (24 times). Although resistance modification was observed at concentrations higher than those that phenothiazines reach in vivo, the potential offered by non-antibiotics justify further animal experiments as well as clinical trials to establish their clinical relevance.

Failure of vancomycin treatment for meningitis caused by vancomycin-susceptible Enterococcus faecium

This case report describes a nosocomial vancomycin-sensitive Enterococcus faecium meningitis with poor response to vancomycin. E. faecium infections continue to represent a therapeutic challenge in Europe, even in countries where vancomycin resistance is still rare. In the case of vancomycin-sensitive E. faecium meningitis, intravenous chloramphenicol should be considered as a treatment option.

Characterization of a heat stable anti-listerial bacteriocin produced by vancomycin sensitive Enterococcus faecium isolated from idli batter.

Lactic acid bacteria (LAB) are known to produce various types of bacteriocins, ribosomally synthesized polypeptides, which have antibacterial spectrum against many food borne pathogens. Listeria monocytogenes, a pathogenic bacterium, is of particular concern to the food industry because of its ability to grow even at refrigeration temperatures and its tolerance to preservative agents. Some of the bacteriocins of LAB are known to have anti-listerial property. In the present study, the bacteriocin produced by vancomycin sensitive Enterococcus faecium El and J4 isolated from idli batter samples was characterized. The isolates were found to tolerate high temperatures of 60°C for 15 and 30 min and 70°C for 15 min. The bacteriocin was found to be heat stable and had anti-listerial activity. The bacteriocin did not lost anti-listerial activity when treated at 100°C for 30 min or at 121°C for 15 min. The bacteriocin lost its antimicrobial activity after treating with trypsin, protinase-K, protease and peptidase.

Freezing Inactivation of Escherichia Coli and Enterococcus Faecalis in Water: Response of Different Strains

The effect of freezing temperature (-7, -15, -30 and -80 degrees C), number of freeze/thaw cycles (1 to 5 cycles) and sample volume (100 mL and 100 microL) on the viability of a pathogenic and an opportunistically pathogenic Escherichia coli, a vancomycin-resistant and a vancomycin-sensitive Enterococcus faecalis were examined. About 3.3 to 4.3 and 1.5 to 2.4 log reduction in cell density were observed in E. coli and E. faecalis, respectively, in the 100 mL samples frozen at -30 degrees C or warmer. Freezing at -80 degrees C was the least effective in killing the microbes, on average the log reduction at -80 degrees C was approximately 1.0 to 1.5 units less than those achieved at the three warmer temperatures. Based on statistical analysis, cell inactivation levels achieved at -7, -15, or -30 degrees C were not significantly different (P-value = 0.1648). There were no statistical difference in terms of log reduction obtained under all experimental conditions for the two E. coli strains (P-value = 0.46) and the two E. faecalis strains (P-value = 0.10). The number of freezing/thaw cycles and sample volume, however, profoundly affected inactivation capacity of freezing. Freezing could be an effective method for further reduction of E. coli and Enterococcus in municipal wastewater/sludge.

Multilocus sequence typing and analysis of putative virulence factors in vancomycin-resistant and vancomycin-sensitive Enterococcus faecium isolates from Brazil

Enterococci are leading causes of hospital-acquired infections that are often difficult to treat because of high-level aminoglycoside and glycopeptide resistance. Vancomycin-resistant enterococci are a global problem, and have been isolated with increasing frequency in hospitals in Brazil. The objective of this study was to determine the genetic relatedness of vancomycin-resistant Enterococcus faecium (VREFM) and vancomycin-sensitive E. faecium (VSEFM) isolated from human infections and faecal sources in Brazil, and to compare these isolates with those from domesticated animals. Isolates (n = 56) were classified by multilocus sequence typing (MLST) and assessed for putative virulence traits. The acm gene was detected in 98% of all isolates. The 56 isolates studied comprised 26 different MLST types. VSEFM isolates from the faeces of pigs were found to be distinct from all human isolates characterised previously by MLST, and were assigned new sequence type (ST) numbers. VREFM isolates were represented by four different STs (ST-114, ST-17, ST-281, ST-50). Among the 26 STs identified in this study, eBURST detected three groups of STs with related allelic profiles, and 19 unrelated STs. Among E. faecium isolates from Brazil, the esp gene was restricted to vancomycin-resistant isolates. Furthermore, isolates classified as ST-17 by MLST, an epidemic strain type isolated internationally with the purK-1 gene, were found among VREFM isolates from Brazil that also harboured the esp and hyl genes.

Successful Treatment of Chronic Bone and Joint Infections with Oral Linezolid

Linezolid is an attractive alternative for the treatment of chronic bone and joint infections because it is active against common pathogens including methicillin-resistant staphylococci and vancomycin-resistant enterococci and because its oral formulation is convenient for long-term administration. To evaluate the ability of linezolid to produce long-term remission, we prospectively monitored 11 consecutive adult patients who received linezolid for osteomyelitis (n = 9) or prosthetic joint infection (n = 2). Linezolid 600 mg was administered orally twice daily for a mean of 10 weeks (range, 6 to 19 weeks). Pathogens were methicillin-resistant Staphylococcus aureus (n = 5), methicillin-resistant coagulase-negative staphylococci (n = 4), vancomycin-resistant Enterococcus faecium (n = 1), and vancomycin-sensitive Enterococcus faecalis (n = 1). After a mean followup of 27 months (range, 17 to 41 months), all 11 patients had remission by clinical, laboratory, and radiographic criteria. During week 8 of linezolid treatment, one patient developed a gram-negative superinfection, which resolved with appropriate therapy. During week 6 of linezolid treatment, one patient developed mild thrombocytopenia and another patient developed mild anemia. Both episodes of myelosuppression were reversible within 10 days after completing the planned 6-week courses of linezolid. We recommend weekly complete blood counts to detect hematologic abnormalities. We conclude that oral linezolid seems to be a useful and convenient alternative for the treatment of bone and joint infections.