Enterococcus gallinarum endocarditis occurring on native heart valves

Non-faecium non-faecalis enterococci: a review of clinical manifestations, virulence factors, and antimicrobial resistance

SUMMARYEnterococci are a diverse group of Gram-positive bacteria that are typically found as commensals in humans, animals, and the environment. Occasionally, they may cause clinically relevant diseases such as endocarditis, septicemia, urinary tract infections, and wound infections. The majority of clinical infections in humans are caused by two species: Enterococcus faecium and Enterococcus faecalis. However, there is an increasing number of clinical infections caused by non-faecium non-faecalis (NFF) enterococci. Although NFF enterococcal species are often overlooked, studies have shown that they may harbor antimicrobial resistance (AMR) genes and virulence factors that are found in E. faecium and E. faecalis. In this review, we present an overview of the NFF enterococci with a particular focus on human clinical manifestations, epidemiology, virulence genes, and AMR genes.

Whole-Genome Sequence of a Clinical Enterococcus gallinarum Strain in a Positive Hemoculture from Siriraj Hospital, Thailand

Enterococcus gallinarum is a rare causative agent of hospital-acquired bacteremia. Here, we reported the complete genome of E. gallinarum strain WKB01, which was directly isolated from a positive hemoculture in Siriraj Hospital, Thailand. Comprehensive analysis demonstrated the clinically relevant tetM gene presenting in its genome.

Enterococcus gallinarum causing cervical vertebral osteomyelitis: imagery detecting the process of rapid progression of degeneration-like change in 3 months

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Blood stream infection of Enterococcus gallinarum can cause osteomyelitis.

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X-ray images of vertebral osteomyelitis shows degeneration-like change.

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The degeneration-like change develops much faster than true degenerative change.

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Enterococcus gallinarum osteomyelitis might require longer period for development.

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Patients with persistent neck or back pain with fever should undergo blood cultures.

We present a series of images of X-rays and MRI of vertebral osteomyelitis caused by Enterococcus gallinarum in a 65-year-old patient with persistent neck pain and fever accompanied by preceding transient biliary enzymes elevation. Images detected progression of degeneration-like changes of C5–7 in three months, which is too rapid for true degeneration and relatively slow for vertebral osteomyelitis of common pathogens. Though initial imagery evaluation detected merely degenerative change, the patient was followed up monthly because of persistent fever. Three months later, the images detected the typical imagery of vertebral osteomyelitis i.e., the destruction of vertebral bone: narrowing of intervertebral spaces with focal osteosclerosis and osteolysis on C5–7 became prominent. At this point, consultation to general internal medicine was made. With grade 3 regurgitation murmur, transthoracic echocardiography was performed and revealed 14-mm-in-diameter vegetation on aortic valve. Blood cultures detected Enterococcus gallinarum of which suspected entry was biliary tract.

No previous case reports of Enterococcus gallinarum referred to vertebral osteomyelitis. While this case showed a typical clinical course of infective endocarditis, the course of progression of vertebral osteomyelitis and perhaps endocarditis was much slower comparing to common pathogens. This might reflect the relatively non-life-threatening features of this organism. Enterococcus gallinarum shows mild resistance to vancomycin and cephalosporins, initial therapy sometimes fails. Enterococcus gallinarum should be newly added to pathogenic candidates of vertebral osteomyelitis especially when feverish patients shows back or neck pain with preceding biliary tract problems.

Enterococcus gallinarum endophthalmitis and meningitis in an allogeneic hematopoietic stem cell transplant patient: A case report and literature review

Endogenous endophthalmitis caused by Enterococcus gallinarum, an organism with intrinsic resistance to vancomycin, has rarely been reported. We present a case of persistent E. gallinarum bacteremia in a female recipient of hematopoietic stem cell transplant (HSCT) complicated by endophthalmitis and meningoventriculitis, resulting in a fatal outcome despite treatment with intravenous ampicillin and daptomycin. Treatment of endophthalmitis often presents a challenge due to the lack of options for antimicrobials with reliable ocular penetration. Therapeutic decisions can become particularly complex with the involvement of drug-resistant pathogens and host characteristics that limit the choice of antimicrobials due to drug toxicity. This case illustrates a rare manifestation of an opportunistic pathogen.

Enterococcal contamination of hospital environments in KwaZulu-Natal, South Africa

AIMS

Enterococci are implicated in hospital-acquired infections and show high tenacity on inanimate objects in the hospital environment. This study investigated the prevalence of Enterococcus spp. in selected wards in public hospitals at four levels of healthcare from a district in KwaZulu-Natal, South Africa.

METHODS AND RESULTS

Swabs were collected from frequently touched areas in the paediatric wards and intensive care units (ICUs). Presumptive Enterococcus spp. were isolated and confirmed to genus and species levels, followed by Kirby-Bauer disk diffusion against 14 antibiotics. The results showed that enterococci were recovered from all 11 surfaces tested with the highest contamination rate observed on occupied beds and mops used to clean floors. A total number of 295 Enterococcus was identified. Polymerase chain reaction identified Enterococcus faecalis 83.1% (245/295) and Enterococcus faecium 12.9% (38/295), while whole genome sequencing identified Enterococcus gallinarum 2.0% (6/295) and Enterococcus casseliflavus 2.0% (6/295). Significant prevalence was observed in paediatric wards 64.1% (189/295) compared with the ICUs 35.9% (106/295), p < 0.05, in central, regional and district hospitals. Collectively, 82.0% (242/295) of enterococcal isolates were multidrug resistant, and 80 different antibiograms were observed. The most prominent antibiogram for E. faecium was CIP-RIF-NIT-TET-ERY and for E. faecalis CIP-TET-ERY.

CONCLUSION

E. faecalis was the most frequent enterococcal species isolated in all the hospitals investigated and correlates with studies conducted elsewhere. A substantially greater number of isolates were recovered from the paediatric wards compared with ICUs, and thus improved standards should be developed for infection control practices. It is suggested that the elevated use of antibiotics contributed to the increased nonsusceptible isolates observed from ICUs. This study highlighted the high recovery rate of enterococci in the hospital environment even in a nonoutbreak setting.

SIGNIFICANCE AND IMPACT OF THE STUDY

Enterocci had a high prevalence rate on the surfaces within the hospitals studied. This study gives an insight into the possible roles all healthcare staff may play in infection control intervention, including proper handling of hospital cleaning equipment and lack of knowledge about the potential for bacteria dissemination.

Successful treatment of aortic valve endocarditis caused by Enterococcus casseliflavus: a case report

Background

Enterococcus casseliflavus is rarely isolated from human specimens. To the best of our knowledge, there are no reports on its detailed treatment course and prognosis. Here, we present the first known case of E. casseliflavus endocarditis with a detailed treatment course.

Case presentation

An 86-year-old Japanese woman was transferred to the emergency department with dyspnoea, wheezing, and lumbago. Her medical history included hypertension, chronic kidney disease, idiopathic interstitial pneumonia, and rectal carcinoma. Physical examination revealed expiratory wheezes and a diastolic murmur (Levine 2/6) at the 4th right sternal border. Chest radiography revealed bilateral interstitial opacities and slight cardiac dilatation. Transthoracic echocardiography demonstrated the presence of mobile vegetation with perforation, prolapse, and regurgitation of the aortic valve. With a suspicion of infective endocarditis, we started administering intravenous ampicillin/sulbactam. Thereafter, blood cultures identified E. casseliflavus through matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. The antimicrobial treatment was then switched to ampicillin plus gentamicin. The patient underwent aortic valve replacement on the thirteenth hospital day. She was administered intravenous ampicillin and gentamicin for 6 weeks. The patient was discharged 8 weeks after admission.

Conclusions

Our case demonstrated that E. casseliflavus could cause infective endocarditis, which can be successfully treated with a 6-week regimen of ampicillin and gentamicin in combination with proper surgical treatment.

The Need of Enterococcal Coverage in Severe Intra-Abdominal Infection: Evidence from Animal Study

Intra-abdominal infection (IAI) is a common and important cause of infectious mortality in intensive care units. Adequate source control and appropriate antimicrobial regimens are key in the management of IAI. In community-acquired IAI, guidelines recommend the use of different antimicrobial regimens according to severity. However, the evidence for this is weak. We investigated the effect of enterococcal coverage in antimicrobial regimens in a severe polymicrobial IAI model. We investigated the effects of imipenem/cilastatin (IMP) and ceftriaxone with metronidazole (CTX + M) in a rat model of severe IAI. We observed the survival rate and bacterial clearance rate. We identified the bacteria in blood culture. We measured lactate, alanine aminotransferase (ALT), creatinine, interleukin (IL)-6, IL-10, and reactive oxygen species (ROS) in the blood. Endotoxin tolerance of peripheral blood mononuclear cells (PBMCs) was also estimated to determine the level of immune suppression. In the severe IAI model, IMP improved survival and bacterial clearance compared to CTX + M. Enterococcus spp. were more frequently isolated in the CTX + M group. IMP also decreased plasma lactate, cytokine, and ROS levels. ALT and creatinine levels were lower in IMP group. In the mild-to-moderate IAI model, however, there was no survival difference between the groups. Immune suppression of PBMCs was observed in IAI model, and it was more prominent in the severe IAI model. Compared to CTX + M, IMP improved the outcome of rats in severe IAI model.

Infective endocarditis due to Streptococci and Enterococci: A 3-year retrospective study

Introduction

Infective endocarditis (IE) is an infection of the heart valves with an aggregation of bacteria in a fibrin plaque called vegetation.

Aims and Objectives

This is a retrospective study of all infective endocarditis cases due to alpha haemolytic streptococci and enterococci.

Methods

All cases of infective endocarditis cases due to alpha haemolytic streptococci and enterococci in a period of three years from 1^st January 2010 to 31^st December 2012 were included. Isolation of the same organism from more than one set of blood cultures was taken as a confirmed case of infective endocarditis. Clinical and serological parameters were recorded using a proforma.

Results

Native valve endocarditis was more common with only five prosthetic valves being involved. Out of 89 clinically suspected cases of IE in the three years from Jan 2010 to Dec 2012, for which blood was sent for culture, 63(70.78%) samples were positive by culture. Of these, 42/63(66.66%) were due to alpha-lytic Streptococci, enterococci and rare gram positive cocci. The rare ones included Enterococcus gallinarum, abiotropha defective, Vagococcus fluvialis and Nutritionally Variant Streptococci(NVS). High level Aminoglycoside resistance(HLAR) was also encountered. The varied and important features of these isolates are discussed. Complications and treatment are described.

Conclusion

From a clinical microbiology point of view, the major challenge faced by the microbiologist in diagnosis of IE is proper aseptic collection of sample before starting antibiotics with a need for multiple samples to detect and also to prove the causative organism. Sensitivity reporting can be a difficult task in the context of NVS, HLAR and gram positives that are slow growing. Congestive failure and embolisation occurs even when the antibiotic treatment is successful.When patients go in for complications, it is very rarely due to wrong antibiotics.

Prevalence and antimicrobial susceptibility pattern of Enterococcus species isolated from different clinical samples at Black Lion Specialized Teaching Hospital, Addis Ababa, Ethiopia

OBJECTIVE

Enterococci which are parts of the normal intestinal flora are opportunistic human pathogens. Their increasing importance is largely due to their resistance to antimicrobials. So the aim this study was to determine the prevalence and antimicrobial pattern of Enterococcus spp.

RESULT

From the total of 422 samples processed, 15 Enterococcus species were isolated. In this study, linezolid were the drug of choice for Enterococcus species, which showed 100% sensitive followed by vancomycin 93.3% sensitive. In contrast, highly resistance (80%) was observed for ampicillin followed by doxycycline (73.3%). All of isolated Enterococci were sensitive to linezolid, however, resistance was observed to common antibiotics. The presence of multidrug resistant Enterococci in our study should be considered as an alarm for Enterococcal infections.

Eggshells as a source for occupational exposure to airborne bacteria in hatcheries

Occupational exposure to high concentrations of airborne bacteria in poultry production is related to an increased risk of respiratory disorders. However, potential sources and formation of hatchery bioaerosols are rarely characterized. In this study, bacterial multiplication on fresh shell fragments from turkey hatching eggs under conditions present in a hatcher incubator was investigated. A 10⁵-fold amplification was observed both by colony count and total cell count gaining 4 × 10⁷ cfu/cells per gram eggshell within 30 hr of incubation. Furthermore, the bacterial community present on eggshells was analyzed by generation of 16S rRNA gene clone libraries and identification of eight isolates. RFLP analysis revealed no shift in community composition during incubation and Enterococcus faecalis and Enterococcus gallinarum were found as the predominant species on turkey eggshells, both have been classified as risk group 2 microorganisms (German TRBA 466). Since Enterococcus spp. were found as predominant species on turkey eggshells, contribution of this genus to bioaerosol formation was demonstrated. During different work activities with poult and eggshell handling concentrations of airborne enterococci up to 1.3 × 10⁴ cfu m^-3 were detected. In contrast, no enterococci were identified at a day without poult or eggshell processing. In conclusion, turkey hatching eggs carry a viable specific microflora from breeder flocks to hatcheries. After hatching of turkey poults, hatcher incubators and eggshell fragments provide appropriate conditions for excessive bacterial growth. Thus, high bacterial loads on eggshell fragments are a source of potential harmful bioaersols caused by air flows, poult activity, and handling of equipment.

Enterococcal endocarditis revisited

The Enterococcus species is the third main cause of infective endocarditis (IE) worldwide, and it is gaining relevance, especially among healthcare-associated cases. Patients with enterococcal IE are older and have more comorbidities than other types of IE. Classical treatment options are limited due to the emergence of high-level aminoglycosides resistance (HLAR), vancomycin resistance and multidrug resistance in some cases. Besides, few new antimicrobial alternatives have shown real efficacy, despite some of them being recommended by major guidelines (including linezolid and daptomycin). Ampicillin plus ceftriaxone 2 g iv./12 h is a good option for Enterococcus faecalis IE caused by HLAR strains, but randomized clinical trials are essential to demonstrate its efficacy for non-HLAR EFIE and to compare it with ampicillin plus short-course gentamicin. The main mechanisms of resistance and treatment options are also reviewed for other enterococcal species.

Antimicrobial resistance profile of Enterococcus species isolated from intestinal tracts of hospitalized patients in Jimma, Ethiopia

Background

Multi-drug-resistant Enterococci colonizing the intestinal tract of hospitalized patients are the major source of infection as well as nosocomial spread. Despite worldwide increasing rate of multidrug resistant Enterococci colonization and infection among hospitalized patients, there is scarcity of data from resource limited setting. The present study aimed at determining the antimicrobial resistance profile of Enterococcus species from intestinal tracts of hospitalized patients in Jimma, Ethiopia.

Methods

The study was conducted among hospitalized patients at Jimma University Specialized Hospital, from January to July 2013. Fecal samples were collected and processed for bacterial isolation and susceptibility testing to antimicrobial agents. Stool samples were inoculated onto enterococcus selective media (Bile Esculin azide agar plate) with and without 6 µg/ml of vancomycin. The isolates were identified to genus and species level by cultural characteristics, Gram’s stain, catalase test, growth in 6.5% NaCl broth, growth at 45°C, motility test and by using API 20 Streptococcus system. Sensitivity testing was done using Kirby–Bauer disk diffusion method. Minimum inhibitory concentrations for vancomycin were determined using E-test strips.

Result

Overall, Enterococci were isolated from 114 (76%) of the study subjects. The isolates were Enterococcus faecium (35.1%) followed by Enterococcusfaecalis (29.8%), Enterococcus gallinarum (17.5%), Enterococcuscasseliflavus (8.8%) and Enterococcusdurans (8.8%). Among 114 tested Enterococci isolates, 41 (36%) were resistant to ampicillin, 62 (54.4%) to streptomycin and 39 (34.2%) to gentamycin. Other alternative antibiotics to treat mixed nosocomial infection caused by Enterococci also showed high rate of resistance in vitro: ciprofloxacin (50% of resistance), norfloxacin (49.1%), erythromycin (63.2%), tetracycline (64.9%), chloramphenicol (34.2%), and nitrofrantoin (32.4%). Multiple drug resistance was observed among 89.5% of E. faecium and E. faecalis. Vancomycin resistant Enterococci were observed in 5% of E. faecium isolates.

Conclusion

This study reveals high rate of fecal colonization by multidrug-resistant Enterococci and prevalence of vancomycin resistance strains. Thus periodic surveillance of antibacterial susceptibilities is recommended to detect emerging resistance and to prevent the spread of antibacterial-resistant strains.

Characterization of an Enterococcus gallinarum Isolate Carrying a Dual vanA and vanB Cassette

The ability of vancomycin resistance determinants to be horizontally transferred within enterococci species is a concern. Identification and characterization of vancomycin-resistant enterococci (VRE) in a clinical isolate have a significant impact on infection control practices. In this study, we describe a clinical isolate of Enterococcus gallinarum exhibiting high-level resistance to vancomycin and teicoplanin. The genetic characterization of this isolate showed the presence of vanA and vanB genes in addition to the naturally carried vanC gene. vanA was identified on pA6981, a 35,608-bp circular plasmid with significant homology to plasmid pS177. The vanB operon was integrated into the bacterial chromosome and showed a high level of homology to previously reported Tn1549 and Tn5382. To the best of our knowledge, this is the first report of E. gallinarum carrying both vanA and vanB operons, indicating the importance of identifying the vancomycin resistance mechanism in non-E. faecium and non-E. faecalis enterococcal species.

Co-colonization of vanA and vanB Enterococcus faecium of clonal complex 17 in a patient with bacteremia due to vanA E. faecium

A 53-year-old Vietnamese man with liver cirrhosis was transferred from a Vietnamese hospital to our tertiary care hospital in Korea in order to undergo a liver transplantation. Bacteremia due to vanA Enterococcus faecium was diagnosed, and stool surveillance cultures for vancomycin-resistant enterococci (VRE) were positive for both vanA and vanB E. faecium. Pulsed-field gel electrophoresis analysis revealed that the 2 vanA VRE isolates from the blood and stool were clonal, but the vanB VRE was unrelated to the vanA VRE. vanA and vanB VRE were ST64 and ST18, single-allele variations of clonal complex 17, respectively. This is the first case report of vanA VRE bacteremia in a Vietnamese patient and demonstrates the reemergence of vanB VRE since a single outbreak occurred 15years ago in Korea. The reemergence of vanB VRE emphasizes the importance of VRE genotyping to prevent the spread of new VRE strains.

Risk factors for vancomycin-resistant enterococci colonisation in critically ill patients

Vancomycin-resistant enterococci (VRE) are important hospital pathogens and have become increasingly common in patients admitted to the intensive care unit (ICU). To determine the incidence and the risk factors associated with VRE colonisation among ICU patients, active surveillance cultures for VRE faecal carriages were carried out in patients admitted to the ICU of the University Hospital of Uberlândia, Minas Gerais, Brazil. Risk factors were assessed using a case-control study. Seventy-seven patients (23.1%) were found to be colonised with vanC VRE and only one patient (0.3%) was colonised with vanA VRE. Independent risk factors for VRE colonisation included nephropathy [odds ratio (OR) = 13.6, p < 0.001], prior antibiotic use (OR = 5.5, p < 0.03) and carbapenem use (OR = 17.3, p < 0.001). Our results showed a higher frequency (23.1%) of Enterococcus gallinarum and Enterococcus casseliflavus, species that are intrinsically resistant to low levels of vancomycin (vanC), without an associated infection, associated with prior antibiotic use, carbapenem use and nephropathy as comorbidity. This study is the first to demonstrate the risk factors associated with vanC VRE colonisation in ICU hospitalised patients. Although vanA and vanB enterococci are of great importance, the epidemiology of vanC VRE needs to be better understood. Even though the clinical relevance of vanC VRE is uncertain, these species are opportunistic pathogens and vanC VRE-colonised patients are a potential epidemiologic reservoir of resistance genes.

Establishment of normal gut microbiota is compromised under excessive hygiene conditions

BACKGROUND

Early gut colonization events are purported to have a major impact on the incidence of infectious, inflammatory and autoimmune diseases in later life. Hence, factors which influence this process may have important implications for both human and animal health. Previously, we demonstrated strong influences of early-life environment on gut microbiota composition in adult pigs. Here, we sought to further investigate the impact of limiting microbial exposure during early life on the development of the pig gut microbiota.

METHODOLOGY/PRINCIPAL FINDINGS

Outdoor- and indoor-reared animals, exposed to the microbiota in their natural rearing environment for the first two days of life, were transferred to an isolator facility and adult gut microbial diversity was analyzed by 16S rRNA gene sequencing. From a total of 2,196 high-quality 16S rRNA gene sequences, 440 phylotypes were identified in the outdoor group and 431 phylotypes in the indoor group. The majority of clones were assigned to the four phyla Firmicutes (67.5% of all sequences), Proteobacteria (17.7%), Bacteroidetes (13.5%) and to a lesser extent, Actinobacteria (0.1%). Although the initial maternal and environmental microbial inoculum of isolator-reared animals was identical to that of their naturally-reared littermates, the microbial succession and stabilization events reported previously in naturally-reared outdoor animals did not occur. In contrast, the gut microbiota of isolator-reared animals remained highly diverse containing a large number of distinct phylotypes.

CONCLUSIONS/SIGNIFICANCE

The results documented here indicate that establishment and development of the normal gut microbiota requires continuous microbial exposure during the early stages of life and this process is compromised under conditions of excessive hygiene.

Clinical Features and Rate of Infective Endocarditis in Non-Faecalis and Non-faecium Enterococcal Bacteremia

Non-faecalis and non-faecium enterococci are an occasional cause of bacteremia, and some cases of infective endocarditis caused by these pathogens have been reported. However, the rate of infective endocarditis in non-faecalis and non-faecium enterococcal bacteremia is still undetermined. We compared the clinical features and the rate of infective endocarditis of 70 cases of non-faecalis and non-faecium enterococcal bacteremia with those of 65 cases of Enterococcus faecalis bacteremia. Non-faecalis and non-faecium enterococcal bacteremia was more frequently associated with biliary tract infection and polymicrobial bacteremia, and was less frequently associated with infective endocarditis, than was E. faecalis bacteremia (57% vs. 28%, p<0.01; 47% vs. 31%, p=0.05; 1% vs. 14%, p<0.01, respectively).

Regional spread ofvanA- orvanB-positiveEnterococcus gallinarumin hospitals and long-term care facilities in Kyoto prefecture, Japan

Following an outbreak ofvanA-positiveEnterococcus faeciumin 2005 in Kyoto prefecture, regional surveillance of vancomycin-resistant enterococci (VRE) was initiated. This revealedvanA- orvanB-positiveEnterococcus gallinarumin multiple facilities. Eighty-eightvanA-positiveE. gallinarumfaecal carriers from 12 facilities and tenvanB-positiveE. gallinarumfaecal carriers from eight facilities were found. Pulsed-field gel electrophoresis profiles of the first isolate from each facility showed that 11 of the 12vanAisolates and three of the eightvanB-positiveE. gallinarumisolates belonged to a single clone. This study confirms the clonal spread ofvanA- orvanB-positiveE. gallinarumin a region and underlines the importance of surveillance of VRE for the presence of vancomycin resistance determinants.

Enterococcus gallinarum meningitis in an immunocompetent host: a case report

We describe a rare case of a 53-year-old man with a long history of alcohol abuse, with Enterococcus gallinarum meningitis, an organism that rarely causes human infection and is primarily found in the gastrointestinal tract of poultry. The patient improved with high-dose ampicillin and gentamicin therapy. To our knowledge, this is the first Brazilian reported case of E. gallinarum meningitis and probably the first case described in an immunocompetent host.

Bacteremia caused by VanC-type enterococci in a university hospital in Japan: a 6-year survey

We retrospectively examined the clinical and microbiological characteristics of bacteremia caused by intrinsically vancomycin-resistant (VanC-type) enterococci in a university hospital in Japan. Five cases of Enterococcus gallinarum and four of Enterococcus casseliflavus bacteremia were identified during the 6 years of the survey. Of the nine cases, five were related to neutropenic states with hematologic diseases and four were related to biliary tract infection with hepatobiliary or pancreatic diseases. VanC-type enterococci were associated with 12% of all the enterococcal bacteremias, indicating that these species cause bacteremia more frequently in Japan than in previously reported areas.

Functional and safety aspects of enterococci in dairy foods

The genus Enterococcus like other LAB has also been featured in dairy industry for decades due to its specific biochemical traits such as lipolysis, proteolysis, and citrate breakdown, hence contributing typical taste and flavor to the dairy foods. Furthermore, the production of bacteriocins by enterococci (enterocins) is well documented. These technological applications have led to propose enterococci as adjunct starters or protective cultures in fermented foods. Moreover, enterococci are nowadays promoted as probiotics, which are claimed for the maintenance of normal intestinal microflora, stimulation of the immune system and improvement of nutritional value of foods. At the same time, enterococci present an emerging pool of opportunistic pathogens for humans as they cause disease, possess agents for antibiotic resistance, and are frequently armed with potential virulence factors. Because of this "dualistic" nature, the use of enterococci remains a debatable issue. However, based on a long history of safe association of particular enterococci with some traditional food fermentations, the use of such strains appears to bear no particular risk for human health. Abundance of knowledge as well as progress in molecular techniques has, however, enabled exact characterization and safety assessment of strains. Therefore, a balanced evaluation of both, beneficial and undesirable nature of enterococci is required. A clear understanding of their status may, therefore, allow their safe use as a starter, or a probiotic strain. The present review describes the broader insight of the benefits and risks of enterococci in dairy foods and their safety assessment.

Enterococcus gallinarum endocarditis in a diabetic patient

Recent studies pointed out the increasing rate of infective endocarditis (IE) in diabetic patients. As diabetes mellitus (DM) prevalence is expected to increase in the coming years, infective endocarditis could be more frequently reported in these patients. We here describe a rare case of Enterococcus gallinarum endocarditis developing on normal native heart valve in an elderly diabetic woman. Therapeutic options were restricted due to resistance factors of the microorganism, limited guidance in the medical literature, and the patient's history and underlying condition. Despite these challenges, adequate antibiotic therapy led to the patient's recovery.

Bacteraemia associated with a vancomycin-resistant Enterococcus gallinarum strain harbouring both the vanA and vanC1 genes

A case of a post-surgical patient who developed a fatal bloodstream infection caused by high-level vancomycin-resistant Enterococcus gallinarum is reported. The isolate was found to carry both the vanC1 and vanA genes. This is the first report of an invasive infection associated with a vanA E. gallinarum isolate in Brazil.

Antimicrobial and safety aspects, and biotechnological potential of bacteriocinogenic enterococci isolated from mallard ducks (Anas platyrhynchos)

Samples from the intestinal content and carcasses of mallard ducks (Anas platyrhynchos) were evaluated for enterococci with antimicrobial activity, presence of genes coding bacteriocins and their expression, and potential virulence factors. Enterococcus faecalis comprised the largest enterococcal species with antagonistic activity followed by E. faecium, E. hirae, Enterococcus spp., and the non-enterococci. Although all E. faecalis isolates manifested a potent direct antimicrobial activity, no activity was detected in supernatants of most producer cultures. However, all E. faecium isolates showed antimicrobial activity in their supernatants and encoded bacteriocins, although the occurrence in the isolates of several enterocin genes did not always correlate with a higher antagonistic activity in supernatants. The efaAfm determinant was the only virulence gene detected in E. faecium, while E. faecalis showed a larger number of virulence determinants, and E. hirae did not carry any of the virulence genes examined. The rapid identification of genes coding described bacteriocins permits recognition of isolates that are potentially producers of novel bacteriocins. Purification of the antimicrobial activity of E. hirae DCH5 and Lactococcus garvieae DCC43 revealed unique chromatographic fragments after MALDI-TOF mass spectrometry analysis, suggesting the antagonistic peptides were purified to homogeneity. Bacteriocinogenic E. faecium and E. hirae isolates may be considered hygienic for production of bacteriocins, and potentially safe due to their low incidence of potential virulence genes and susceptibility to most clinically relevant antibiotics. However, the presence among the enterococci of E. faecalis strains with a potent antagonistic activity and multiple virulence factors, raises concerns regarding their potential pathogenicity to consumers.

Genes encoding bacteriocins and their expression and potential virulence factors of Enterococci isolated from wood pigeons (Columba palumbus)

Samples of the intestinal content and carcasses of wood pigeons (Columba palumbus) were evaluated for enterococci with antimicrobial activity. Enterococcus faecium comprised the largest enterococcal species with antagonistic activity, followed by Enterococcusfaecalis and Enterococcus columbae. PCR amplification of genes coding bacteriocins and determination of their nucleotide sequence, and the use of specific antipeptide bacteriocin antibodies and a noncompetitive indirect enzyme-linked immunosorbent assay, permitted characterization of enterococci coding that described bacteriocins and their expression. The efaAfm determinant was the only virulence gene detected in E. faecium, whereas E. faecalis showed a larger number of virulence determinants, and E. columbae did not carry any of the virulence genes examined. Although all E. faecalis isolates manifested a potent direct antimicrobial activity, no activity was detected in supernatants of producer cells. Purification of the antagonistic activity of E. columbae PLCH2 showed multiple chromatographic fragments after matrix-assisted laser desorption-ionization time-of-flight mass spectrometry analysis, suggesting the active peptide(s) had not yet purified to homogeneity. Bacteriocinogenic E. faecium and E. columbae isolates may be considered hygienic for production of enterocins and potentially safe due to their low incidence of potential virulence genes and susceptibility of most relevant clinical antibiotics. However, the presence among the enterococci of E. faecalis strains with a potent antagonistic activity and multiple virulence factors is an issue that must be considered further.

Identification of clinically relevant enterococcus species by direct sequencing of groES and spacer region

We determined the groESL sequences (groES, groEL, and the intergenic spacer) of 10 clinically relevant Enterococcus species and evaluated the feasibility of identifying Enterococcus species on the basis of these sequences. Seven common clinical Enterococcus species, E. faecalis, E. faecium, E. casseliflavus, E. gallinarum, E. avium, E. raffinosus, and E. hirae, and three less common Enterococcus species, E. cecorum, E. durans, and E. mundtii, were examined in this study. We found that the groES genes of these enterococcal species are identical in length (285 nucleotides) and contain an unusual putative start codon, GTG. The lengths and sequences of the intergenic regions (spacers between the groES and groEL genes) are quite variable (17 to 57 bp in length) among Enterococcus species but are conserved in strains within each species, with only a few exceptions. Considerable variation of groES or groEL sequences was also observed. The evolutionary trees of groES or groEL sequences revealed similarities among Enterococcus species. However, the overall intraspecies variation of groES was less than that of groEL. The high interspecies variation and low intraspecies variation indicate that the groES and spacer sequences are more useful than groEL for identification of clinically relevant Enterococcus species. The sequences of these two genetic traits, groES and spacer, can be determined by a single PCR and direct sequencing and may provide important information for the differentiation of closely related species of Enterococcus.

First report of VanA Enterococcus gallinarum dissemination within an intensive care unit in Argentina

Enterococcusgallinarum is intrinsically resistant to low levels of vancomycin and has been described as a colonizing microorganism causing bacteraemia and infection among immunosupresed patients. Between August 2000 and February 2001, 15 highly glycopeptide-resistant E. gallinarum isolates, one from blood and the remaining from rectal swabs, were recovered in a general hospital of Buenos Aires Province, Argentina. All isolates were characterized by biochemical assays, and displayed MICs of vancomycin in the range 16-128 mg/l and MICs of teicoplanin in the range 16-32 mg/l. In all cases, PCR analysis yield positive results for both vanC1 and vanA genes. E. gallinarum isolates were classified as two clonal types by SmaI-PFGE: clone A (n = 8) and clone B (n = 7) and both harboured a transferable vanA element.

Antimicrobial resistance of Enterococcus sp. isolated from the intestinal tract of patients from a university hospital in Brazil

This study reports the results about antimicrobial resistance of Enterococcus spp. isolated from intestinal tract of patients from a university hospital in Brazil. The identification of strains at species level was performed by conventional biochemical tests, API 20 Strep (bioMérieux), and polymerase chain reaction assay. The species distribution was E. faecium (34%), followed by E. faecalis (33%), E. gallinarum (23.7%), E. casseliflavus (5.2%), E. avium (1%), and E. hirae (1%). Intrinsic resistance to vancomycin characterized by presence of vanC genes was found in E. gallinarum and E. casseliflavus. The high prevalence of VanC phenotype enterococci is very important because these species have been reported as causing a wide variety of infections. Vancomycin-resistant E. faecium or E. faecalis were not found and no one isolate of these species was a beta-lactamase producer. Thirteen clinical isolates of enterococci (13.4%) showed multiresistance patterns, which were defined by resistance to three classes of antibiotics plus resistance to at least one aminoglycoside (gentamicin and/or streptomycin). The resistance to several antimicrobials shown by enterococcal strains obtained in this study is of concern because of the decrease in the therapeutic options for treatment of infections caused by enterococci.

Pyogenic Liver Abscess Complicating Biliary Stricture Due to Chronic Pancreatitis

BACKGROUND

Chronic pancreatitis uncommonly causes common bile duct stricture, and common bile duct stricture rarely leads to pyogenic liver abscess.

METHODS

We describe a 51-year-old man who developed a pyogenic liver abscess after the development of a common bile duct stricture due to chronic pancreatitis.

RESULTS

The patient required open drainage of the liver abscess and decompressive choledochoduodenostomy. His infection was persistent and he required percutaneous and subsequent open drainage of a second hepatic abscess. The patient died of refractory sepsis and multi-organ failure.

CONCLUSIONS

The relevant English literature concerning pyogenic liver abscesses, specifically in the setting of common bile duct stricture due to chronic pancreatitis, is reviewed and discussed.

Virulence factors in food, clinical and reference Enterococci: A common trait in the genus?

The occurrence of several virulence traits (cytolysin, adhesins and hydrolytic enzymes) was investigated in a collection of 164 enterococci, including food and clinical isolates (from human and veterinary origin), as well as type and reference strains from 20 enterococcal species. Up to fifteen different cyl genotypes were found, as well as silent cyl genes. The occurrence of the cyl operon and haemolytic potential seems to be widespread in the genus. A significant association of this virulent trait with clinical isolates was found (p < 0.05). High levels of incidence were also observed for genes encoding surface adhesins (esp, efaA(fs), efaA(fm)), agg and gelE, irrespectively of species allocation and origin of strains. Although gelE behaves as silent in the majority of the strains, gelatinase activity predominates in clinical isolates, whereas lipase and DNase were mainly detected in food isolates pointing to their minor role as virulence determinants. No hyaluronidase activity was detected for all strains. Numerical hierarchic data analysis grouped the strains in three main clusters, two of them including a total of 50 strains with low number of virulence determinants (from 2 to 7) and the other with 114 strains with a high virulence potential (up to 12 determinants). No statistical association was found between virulence clusters and species allocation (p > 0.10), strongly suggesting that virulence determinants are a common trait in the genus Enterococcus. Clinical strains seem to be significantly associated with high virulence potential, whereas food, commensal and environmental strains harbour fewer virulence determinants (p < 0.01). A high level of relative diversity in virulence patterns was observed (Shannon's index varies from 0.95 to 1.0 among clusters), reinforcing the strain-specific nature of the association of virulence factors. Although a low risk seems to be associated with the use of enterococci in long-established artisanal cheeses, screening of virulence traits and their cross-synergies must be performed, particularly for commercial starters, probiotic strains and products to be used by high risk population groups.