Emergence of unusual species of enterococci causing infections, South India

Refractory Peritonitis Related to Peritoneal Dialysis Caused by Enterococcus gallinarum

A 65-year-old woman with a history of peritoneal dialysis undergoing hemodialysis at our hospital presented with a fever after experiencing gastroenteritis symptoms. She had an implanted peritoneal dialysis catheter for draining chylous ascites. After commencing empirical treatment with meropenem, peritoneal effluent samples revealed an increased white blood cell count, and peritonitis was diagnosed. Enterococcus gallinarum was detected in blood and effluent cultures. Meropenem was changed to vancomycin based on susceptibility testing but subsequently restarted and thereafter changed to ampicillin following exacerbation of peritonitis. Finally, catheter removal led to complete recovery. E. gallinarum is vancomycin-resistant and a rare cause of peritonitis.

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.

Spontaneous resolution or antibiotic effectiveness? Reflection on a case of pediatric urinary tract infections caused by Enterococcus raffinosus

Enterococcus raffinosus, named by Collins et al. in 1989, is a cocci-shaped bacterium that typically appears in pairs or short chains. As a Gram-positive and non-motile bacterium, it grows at 10°C-45°C, exhibiting negative peroxidase activity [1]. It is a normal flora in the oropharynx and gastrointestinal tract of domestic cats [2] and can also be isolated from human rectal swabs [3], it belongs to the same genus Enterococcus as Enterococcus faecalis and Enterococcus faecium. Enterococcus faecalis and Enterococcus faecium constitute 90% of clinically isolated strains. However, the incidence of other enterococci, excluding E. faecalis and E. faecium, is on the rise [4]. In this case report, a patient with pediatric urinary tract infections caused by E. raffinosus was presented, and a summary of relevant literature was provided.

Endophthalmitis caused by Enterococcus casseliflavus: a systematic review of literature

Introduction

Enterococcus casseliflavus is a rare pathogen in human infections, despite being widely distributed in natural environments. This systematic review aims to evaluate the evidence related to endophthalmitis caused by E. casseliflavus.

Methods

A thorough search of PubMed, PubMed Central, and Scopus databases was conducted, covering the period up to October 2022.

Results

A total of 53 records were identified, with 8 studies reporting a total of 21 cases meeting the inclusion criteria. Among these studies, 7 described isolated case reports, while 1 study described 14 cases. The overall quality of the reports was good, as all articles were determined to have low risk of bias. Vancomycin susceptibility was reported in only one case of isolated case reports, while the remaining cases were all vancomycin resistant. With regard to management, in most cases intravenous ampicillin and linezolid were administered, while only one study reported administration of vancomycin.

Conclusions

Ophthalmologists should be aware of the potential for E. casseliflavus to cause endophthalmitis infections and the challenges associated with its intrinsic resistance to vancomycin.

Enterococci Isolated from One-Day-Old Chickens and Their Phenotypic Susceptibility to Antimicrobials in the Czech Republic

Our study describes the prevalence and spectrum of enterococci isolated from one-day-old chickens in the Czech Republic, their level of antimicrobial resistance, and the occurrence of multiresistance. Over a 24-month period from 1 August 2021 to 31 July 2023, a total of 464 mixed samples of one-day-old chicken organs were examined during routine inspections at 12 randomly selected poultry farms in the Czech Republic. The samples were processed via cultivation methods and suspected strains were confirmed using the MALDI-TOF Mass Spectrometry method. Antimicrobial susceptibility was determined using the MIC method for eight antimicrobials. A total of 128 isolates (prevalence of 27.6%) representing 4 species of enterococci were isolated, including Enterococcus faecalis, Enterococcus faecium, Enterococcus gallinarum, and Enterococcus hirae, with prevalence rates of 23.3%, 1.5%, 2.2%, and 0.6%, respectively. Susceptibility tests showed a high percentage of susceptible strains among E. faecalis, E. faecium, and E. gallinarum for penicillin-based antibiotics, sulfamethoxazole with trimethoprim, and florfenicol (80-100% susceptible strains). E. hirae was an exception, displaying complete resistance to enrofloxacin (0% susceptible strains) and a high degree of resistance to other tested antimicrobials (33.3% susceptible strains). Among the isolated strains, a total of 16 isolates (12.5%) showed resistance to 3 or more antimicrobials. Complete resistance to all eight antimicrobials simultaneously was observed in four isolates (3.1%). This research shows the possible sources of pathogenic enterococci and their virulence and resistance genes. The findings hold relevance for both veterinary and human medicine, contributing to a better understanding of enterococcal circulation in the human ecosystem and food chain, as well as the development of their resistance and multiresistance.

Antimicrobial susceptibility pattern of enterococci isolated from various clinical samples in a tertiary care hospital in India

Background and objectives: Enterococci are significant human pathogens that are capable of causing various nosocomial infections. This study determined the antibiotic susceptibility pattern of enterococcal species isolated from various clinical specimens with special reference to vancomycin-resistant enterococci. Material and methods: The study was carried out for 6 months on enterococci isolated from various clinical specimens at a tertiary care hospital. Organisms were identified by standard procedures, and subjected to antimicrobial testing as per the standard guidelines. Results: Total 116 enterococci were isolated from various clinical samples. Of the total isolates, 56.9%, 30.2% and 12.9% were isolated from indoor, intensive care unit and non-hosptalized (outdoor) patients respectively.The most common Enterococcus species from blood was E. faecium (72%) followed by E. faecalis (12%) and E. galinarrium (9.4%). Out of 116 enterococci isolates, 31 (26.7%) were resistant to vancomycin and only 1 (0.9%) was resistant to linezolid. Conclusion:The study demonstrated high prevalence of multidrug-resistant enterococci in our hospital setting, thus posing a serious therapeutic challenge. The result would be useful in monitoring the future trends of antimicrobial susceptibility of enterococci in this region. *Correspondence: Dr. Nikunja Kumar Das, Department of Microbiology, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Dr. D. Y. Patil Vidyapeeth, Pimpri, Pune, Maharashtra, India-411018. E-mail: nikunjdas3085@gmail.com IMC J Med Sci. 2023; 17(2):004. DOI: https://doi.org/10.55010/imcjms.17.014

Antimicrobial Resistance and Biofilm Formation in Enterococcus spp. Isolated from Humans and Turkeys in Poland

Enterococci are a natural component of the intestinal flora of many organisms, including humans and birds. As opportunistic pathogens, they can cause fatal infections of the urinary tract and endocarditis in humans, whereas in poultry symptoms are joint disease, sepsis, and falls in the first week of life. The study covered 107 Enterococcus strains—56 isolated from humans and 51 from turkeys. Among the isolates investigated Enterococcus faecalis was detected in 80.36% of human and 80.39% of turkey samples. Enterococcus faecium was identified in 8.93% of human and 17.65% of turkey strains. The highest percentage of the strains was resistant to tetracycline as follows: 48 (85.71%) and 48 (94.12%) of human and turkey strains, respectively. Resistance to erythromycin occurred in 37.50% of the human and in 76.47% of turkey strains, otherwise 27.10% of all strains showed resistance to ciprofloxacin. Our study revealed that 25% of human and 15.69% of turkey strains were resistant to vancomycin. Multidrug resistance showed in 32.14% and 43.14% of human and turkey strains, respectively. The tetracycline resistance gene, tetM, was detected in 82.24% of all strains analyzed, whereas the tetO gene was found in 53.57% of human but only in 7.84% of turkey strains. The vancomycin resistance gene (vanA) was detected in seven Enterococcus strains (six isolated from turkeys and one from humans). The ermB gene (resistance to macrolide) was detected in 55.14% of all isolates (42.86% of human and 68.63% of turkey strains), whereas the ermA gene was detected in 17.65% of turkey but only in 3.57% of human isolates. All the strains had the ability to form biofilms. A stronger biofilm was formed after 24-hour incubation by strains isolated from turkeys, whereas after 48 hours of incubation all examined strains produced strong biofilm.

Using groEL as the target for identification of Enterococcus faecium clades and 7 clinically relevant Enterococcus species

BACKGROUND/PURPOSE

Accurate identification is important for effective treatment because Enterococcus species have talents to cope with various antibiotics either by intrinsic resistance or by acquisition of mobile genetic elements. The groEL gene is a permissive target in identification of bacteria. We aimed to develop simple assays based on groEL for identification of enterococci.

RESULTS

We continued our previous work and determined groEL gene sequences of Enterococcus species isolated from clinical specimens. Phylogenetic analysis based on groEL revealed that each strain clustered well with their reference strains (bootstrap value 100%), in which Enterococcusfaecium and Enterococcusgallinarum could be split into two clades. The divergence of E. faecium was coincident with hospital-associated clade, known as clade A, and community-associated clade, known as clade B. A PCR-restriction fragment length polymorphism (PCR-RFLP) assay was therefore designed to differentiate the two E. faecium clades, based on the specific RsaI cutting sites present in the two clades. To differentiate 7 clinical relevant Enterococcus species, the multiplex PCR assay was designed to identify Enterococcusavium, Enterococcuscasseliflavus, Enterococcusfaecalis, E. faecium, E. gallinarum, Enterococcushirae and Enterococcusraffinosus. Specificity was tested with other Enterococcus species including Enterococcuscecorum, Enterococcusdurans and Enterococcusmundtii. None of these bacterial species generated products of similar size to those of the seven Enterococcus species.

CONCLUSION

The simple PCR-RFLP and multiplex PCR assays on the basis of groEL gene provided an alternative way to identify Enterococcus species.

Clinical management of non-faecium non-faecalis vancomycin-resistant enterococci infection. Focus on Enterococcus gallinarum and Enterococcus casseliflavus/flavescens

Enterococcus gallinarum and Enterococcus casseliflavus/flavescens are enterococci intrinsically resistant to vancomycin belonging to the E. gallinarum group. They are responsible mainly for healthcare-associated infections, in particular bloodstream, urinary tract and surgical wound infections. Diseases due to these bacteria are significantly increasing worldwide, as they are prone to cause infection in patients with concurrent hepatobiliary or oncohematological disorders. Along with their distinguishing vancomycin resistance, due to a chromosomally-encoded VanC operon, their additional intrinsic resistance to many antibiotics other than glycopeptides limits the therapeutic choices. In addition, their intrinsic vancomycin resistance, unlike the vancomycin resistance of Enterococcus faecalis and Enterococcus faecium caused by transmissible plasmids, poses different infection control issues. We focused on the therapeutic and infection control issues of clinical syndromes caused by E. gallinarum and E. casseliflavus/flavescens. We propose therapeutic algorithms on bloodstream infections, endocarditis, central nervous system infections, endophthalmitis and urinary tract infections. The implementation of infection control measures in cases of E. gallinarum and E. casseliflavus/flavescens infection or colonization should be evaluated on a case-by-case basis, especially for epidemic outbreaks or for isolates supposed to harbor a potential transmissible vancomycin-resistance phenotype.

Susceptibility Pattern of Enterococci at Tertiary Care Hospital

The study was aimed to characterize enterococci from various clinical specimens, to determine the antimicrobial susceptibility pattern, and to explore the association between virulence factors and antimicrobial resistance. A total of 283 clinical enterococcal isolates were speciated and subjected to antimicrobial susceptibility testing. Virulence factors (hemolysin, gelatinase, and biofilm production) were detected phenotypically. Of the 283 enterococci isolated, 12 species were identified; predominant species were Enterococcus faecalis (82.33%). High-level gentamicin (HLG) and vancomycin resistance were observed among 55.57% and 6.01% of enteroccal isolates, respectively. All vancomycin-resistant enterococci (VREs) were E. faecalis and had VanA phenotype and genotype. Hemolysin, gelatinase, and biofilm production were seen in 15.90%, 12.36%, and 13.43% of enterococcal isolates, respectively. Vancomycin and HLG resistance were observed in 0.35% and 61.86% of the enterococcal isolates producing virulence factors. Isolates resistant to HLG but susceptible to vancomycin expressed more virulent factors. Further research is required to reveal the complex interplay between drug resistance and virulence factors.

Acute Pyelonephritis with Bacteremia Caused by Enterococcus hirae: A Rare Infection in Humans

Enterococci are one of the usual residents of the microflora in humans. In the last decade this genus has been reported as the third most common cause of bacteremia. We present the case of a 78-year-old female who was admitted to the emergency room because of nausea, lipothymia, and weakness. She was diagnosed with a pyelonephritis with bacteremia, with the isolation in blood and urine cultures of Escherichia coli and Enterococcus hirae. This last microorganism is a rarely isolated pathogen in humans. Currently it is estimated to represent 1–3% of all enterococcal species isolated in clinical practice.

Bioprosthetic Aortic Valve Endocarditis in Association with Enterococcus durans

Enterococci are common organisms associated with endocarditis, but infection by Enterococcus durans is very rare. To our knowledge, only 3 cases have been reported in the medical literature, and all 3 have involved native valves. Here we publish the first reported case (to our knowledge) of E. durans endocarditis in association with a bioprosthetic aortic valve. After the organism and its antibiotic susceptibility were identified, the 74-year-old male patient was treated successfully with teicoplanin and gentamicin, over a course of 6 weeks.

Molecular Characterization of Virulence Genes in Vancomycin-Resistant and Vancomycin-Sensitive Enterococci

Background:

The aim of this study was to find out the correlation between presence of virulence (gelatinase [gel E], enterococcal surface protein [esp], cytolysin A [cyl A], hyaluronidase [hyl], and aggregation substance [asa1]) and vancomycin-resistant genes (van A and van B) in enterococci, with their phenotypic expression.

Materials and Methods:

A total of 500 isolates (250 each clinical and fecal) were processed. Enterococci were isolated from various clinical samples and from fecal specimens of colonized patients. Various virulence determinants namely asa1, esp, hyl, gel E, and cyl were detected by phenotypic methods. Minimum inhibitory concentration (MIC) of vancomycin was determined by agar dilution method. Multiplex polymerase chain reaction (PCR) was used to detect the presence of virulence and van genes.

Results:

Out of all the samples processed, 12.0% (60/500) isolates carried van A or van B genes as confirmed by MIC test and PCR methods. Genes responsible for virulence were detected by multiplex PCR and at least one of the five was detected in all the clinical vancomycin-resistant enterococci (VRE) and vancomycin-sensitive enterococci (VSE). gel E, esp, and hyl genes were found to be significantly higher in clinical VRE. Of the fecal isolates, presence of gel E, esp, and asa1 was significantly higher in VRE as compared to VSE. The presence of hyl gene in the clinical VRE was found to be statistically significant (P = 0.043) as against the fecal VRE. Correlation between the presence of virulence genes and their expression as detected by phenotypic tests showed that while biofilm production was seen in 61.1% (22/36) of clinical VRE, the corresponding genes, i.e., asa1 and esp were detected in 30.5% (11/36) and 27.8% (10/36) of strains only.

Conclusion:

Enterococcus faecium isolates were found to carry esp gene, a phenomenon that has been described previously only for Enterococcus faecalis, but we were unable to correlate the presence of esp with their capacity to form biofilms.

Modified 16S-23S rRNA intergenic region restriction endonuclease analysis for species identification of Enterococcus strains isolated from pigs, compared with identification using classical methods and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Fast and reliable identification of bacteria to at least the species level is currently the basis for correct diagnosis and appropriate treatment of infections. This is particularly important in the case of bacteria of the genus Enterococcus, whose resistance profile is often correlated with their species (e.g. resistance to vancomycin). In this study, we evaluated restriction endonuclease analysis of the 16S-23S rRNA gene intergenic transcribed spacer (ITS) region for species identification of Enterococcus. The utility of the method was compared with that of phenotypic methods [biochemical profile evaluation and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)]. Identification was based on 21 Enterococcus reference strains, of the species E. faecalis, E. faecium, E. hirae, E. durans, E. casseliflavus, E. gallinarum, E. avium, E. cecorum and E. columbae, and 47 Enterococcus field strains isolated from pigs. Restriction endonuclease analysis of the ITS-PCR product using HinfI, RsaI and MboI, in the order specified, enabled species differentiation of the Enterococcus reference and field strains, and in the case of the latter, the results of species identification were identical (47/47) to those obtained by MALDI-TOF MS. Moreover, as a result of digestion with MboI, a unique restriction profile was also obtained for the strains (3/3) identified by MALDI-TOF MS as E. thailandicus. In our opinion, restriction endonuclease analysis of the 16S-23S rRNA gene ITS region of Enterococcus may be a simple and relatively fast (less than 4 h) alternative method for identifying the species occurring most frequently in humans and animals.

Potential impact of antimicrobial resistance in wildlife, environment and human health

Given the significant spatial and temporal heterogeneity in antimicrobial resistance distribution and the factors that affect its evolution, dissemination, and persistence, it is important to highlight that antimicrobial resistance must be viewed as an ecological problem. Monitoring the resistance prevalence of indicator bacteria such as Escherichia coli and enterococci in wild animals makes it possible to show that wildlife has the potential to serve as an environmental reservoir and melting pot of bacterial resistance. These researchers address the issue of antimicrobial-resistant microorganism proliferation in the environment and the related potential human health and environmental impact.

Brain Abscess Caused by Enterococcus avium: A Case Report and Review of the Literature

Brain abscesses can be highly lethal if appropriate treatment is not administered, and reports of such an abscess caused by Enterococcus avium are very rare. Here,we report a case of a 48-year-old man presenting with chronic otitis media. He initially presented with a headache and right otalgia. An otoscopic evaluation performed on the day of admission showed exudation of fresh pus from the right ear. Brain magnetic resonance imaging demonstrated a hypodense area in the right temporoparietal lobe, suggestive of a brain abscess. A culturing of the ear discharge and brain abscess aspirate proved of E. avium infection. Following stereotactic aspiration of the brain abscess and proper antimicrobial treatment, the patient recovered completely. In this report, we also review and discuss the available medical literature on previous cases of E. avium infection associated with brain abscess.

Genetic characterization of antibiotic resistance and virulence factors in Enterococcus spp. from Japanese retail ready-to-eat raw fish

Little information is available on the diversity and distribution of resistance and virulence factors in enterococci isolated from retail fish. In this study, 200 samples of retail ready-to-eat raw fish (sashimi) collected from the Japanese prefecture of Hiroshima were analyzed for incidence of Enterococcus spp. We recovered 96 enterococcal isolates from 90 (45%, 90/200) samples. Fifty-six strains were identified at the species level: E. faecalis (n = 31), E. faecium (n = 7), E. casseliflavus (n = 7), E. gallinarum (n = 3), E. phoeniculicola (n = 4), E. raffinosus (n = 2), E. saccharolyticus (n = 1), and E. gilvus (n = 1). Twenty-five (26%, 25/96) strains carried antibiotic resistance genes. These included the tet(M), tet(L), tet(K), erm(B), msr(A/B), aph(3'), and blaZ genes, which were detected in 12.5%, 9.3%, 2%, 14.5%, 1%, 1%, and 2% of isolates, respectively. The virulence genes gelE and asa1 were detected in 31 and 24 E. faecalis strains, respectively. Both genes were detected in one E. faecium strain. In conclusion, this is the first study to underscore the importance of sashimi as not only a reservoir of Enterococcus spp. carrying resistance and virulence genes, but also a reservoir for unusual Enterococcus spp.

Spontaneous bacterial peritonitis with sepsis caused by Enterococcus hirae

Selective intestinal decontamination (SID) with norfloxacin has been widely used for the prophylaxis of spontaneous bacterial peritonitis (SBP) because of a high recurrence rate and preventive effect of SID for SBP. However, it does select resistant gut flora and may lead to SBP caused by unusual pathogens such as quinolone-resistant gram-negative bacilli or gram-positive cocci. Enterococcus hirae is known to cause infections mainly in animals, but is rarely encountered in humans. We report the first case of SBP by E. hirae in a cirrhotic patient who have previously received an oral administration of norfloxacin against SBP caused by Klebsiella pneumoniae and presented in septic shock.

Enterococcus hirae-related acute pyelonephritis and cholangitis with bacteremia: an unusual infection in humans

Very few reports are available from the literature related to Enterococcus hirae infection in humans, which is more frequently seen in animals and birds. We report two patients with E hirae bacteremia caused by acute pyelonephritis and acute cholangitis. The clinical courses have been smooth on use of sensitive antibiotic therapy. In both cases, the primary sources and portals of entry are clearly identified.

Antimicrobial resistance of enterococci isolated from mastitic bovine milk samples in Korea

The aim of this study was to determine the antimicrobial resistance of various species of enterococci isolated from mastitic bovine milk samples. A total of 105 enterococci isolates were examined: Enterococcus faecalis (n = 47), Enterococcus faecium (n = 39), Enterococcus gallinarum (n = 6), Enterococcus avium (n = 6), Enterococcus hirae (n = 5) and Enterococcus durans (n = 2). All the isolates were susceptible to ampicillin, gentamicin and vancomycin, and only a single E. hirae isolate was resistant to ampicillin. In general, the most frequently observed resistance among the enterococcal isolates was to tetracycline (69.5%), followed by penicillin (64.7%), erythromycin (57.1%) and cephalothin (44.7%). A similar antimicrobial resistance pattern was observed among individual species except E. durans, which exhibited only tetracycline resistance. Resistance observed among isolates of E. hirae and E. gallinarum was almost as high as E. faecium and E. faecalis. Of 105 isolates, only six (5.7%) strains of E. faecium were susceptible to all the antimicrobials tested and about 52% (55/105) showed resistance to more than three antimicrobials. The most common multiple resistance pattern was penicillin, tetracycline and erythromycin, which was observed in 32 of 105 (30.4%) isolates. This study demonstrates that enterococcal isolates belonging to minor species showed antimicrobial resistance rates as high as those of E. faecium and E. faecalis, and that monitoring of antimicrobial resistance should not be restricted only to those two major species.

Stored-product insects carry antibiotic-resistant and potentially virulent enterococci

A total of 154 enterococcal isolates from 95 stored-product insects collected from a feed mill, a grain storage silo, and a retail store were isolated and identified to the species level using PCR. Enterococcus casseliflavus represented 51% of the total isolates, followed by Enterococcus gallinarum (24%), Enterococcus faecium (14%), Enterococcus faecalis (7%), and Enterococcus hirae (5%). Many isolates were resistant to tetracycline (48%), followed by streptomycin (21%), erythromycin (14%), kanamycin (13%), ciprofloxacin (12%), ampicillin (4%), and chloramphenicol (<1%). Enterococci carried genes coding for virulence factors, including the gelatinase gene gelE (26% of isolates), an enterococcal surface protein gene esp (1%), and the cytolysin gene cylA (2%). An aggregation substance (asa1) gene was detected in six out of 10 E. faecalis isolates and five of these were positive for the aggregation substance. Enterococci were positive for hemolytic (57% of isolates) and gelatinolytic (23%) activity. The filter-mating assay showed that the tetracycline resistance gene, tetM, was transferable among E. faecalis by conjugation. These data demonstrated that stored-product insects can serve as potential vectors in disseminating antibiotic-resistant and potentially virulent enterococci.

Bacteremia caused by non-faecalis and non-faecium enterococcus species at a Medical center in Taiwan, 2000 to 2008

SUMMARY OBJECTIVES

Human infections due to non-faecalis and non-faecium Enterococcus species are emerging but data on the characteristics of these infections are limited.

METHODS

We retrospectively reviewed the computerized database of the bacteriology laboratory at National Taiwan University Hospital from January 2000 through December 2008 to identify patients with non-faecalis and non-faecium enterococcal bacteremia.

RESULTS

Enterococcal bacteremia was diagnosed in 1887 patients during the study period and was caused by non-faecalis and non-faecium enterococci in 182 (9.6%) of these patients. The causative organisms included Enterococcus casseliflavus (n = 59, 3.1%), Enterococcus gallinarum (n = 58, 3.0%), Enterococcus avium (n = 45, 2.4%), Enterococcus hirae (n = 9, 0.5%), Enterococcus raffinosus (n = 9, 0.5%), Enterococcus durans (n = 2, 0.1%), Enterococcus cecorum (n = 2, 0.1%), and Enterococcus canintestini (n = 1, 0.5%). A commercially-available phenotypic identification system misidentified six isolates based upon sequence analysis of 16S and groESL genes. Among the 182 patients, 74 (40.7%) had catheter-associated bloodstream infection and 69 (37.9%) presented with biliary tract infection. Healthcare-associated enterococcal bacteremia comprised 99 (54.4%) episodes and a polymicrobial etiology was found in 106 (58.2%) episodes. The clinical manifestations varied between the infecting Enterococcus species. Multivariate logistic regression showed that immunocompromised status is the only risk factor for the all cause mortality.

CONCLUSIONS

Non-faecalis and non-faecium Enterococcus species can cause protean manifestations which vary with the infecting Enterococcus species. Misidentification of unusual enterococcal species might occur by the commercial identification methods and accurate identification with molecular methods is required.

Emerging antibiotic resistance in bacteria with special reference to India

The antibiotic era started in the 1940s and changed the profile of infectious diseases and human demography. The burgeoning classes and numbers promised much and elimination of this major cause of human (and animal) morbidity appeared possible. Bacterial antibiotic resistance which was observed soon after antibiotic introduction has been studied extensively. Diverse mechanisms have been demonstrated and the genetic basis elucidated. The resilience of the prokaryote ecosystems to antibiotic stress has been realized. The paper presents these subjects briefly to afford an overview. The epidemiology of antibiotic resistance is dealt with and community practices in different countries are described. The role of high antibiotic usage environments is indicated. The implication of the wide use of antibiotics in animals has been pointed out. Steadily increasing antibiotic resistance and decreasing numbers of newer antibiotics appear to point to a post-antibiotic period during which treatment of infections would become increasingly difficult. This article attempts to review the global antimicrobial resistance scene and juxtaposes it to the Indian experience. The prevalence in India of antibiotic resistance among major groups of pathogens is described. The factors that determine the prevalent high antibiotic resistance rates have been highlighted. The future research activity to ensure continued utility of antibiotics in the control of infections has been indicated.

First report of vaginal infection caused by Enterococcus raffinosus

The authors have reported the first case of vaginal infection caused by Enterococcus raffinosus. The latter is a rarely identified species, but some of the infections described in the literature should direct some attention to this, often opportunistic pathogen, and its emerging multidrug resistance.

Multidrug-resistant Enterococcus raffinosus from a decubitus ulcer: a case report

A case of decubitus ulcer infected with multidrug-resistant Enterococcus raffinosus is reported in this article. This is the first report of wound infection caused by an Enterococcus raffinosus isolate resistant to antibiotics other than beta-lactams, gentamicin, and ciprofloxacin. This case adds to the knowledge base concerning the onset of antibiotic resistance in this uncommon species and confirms the emerging role of daptomycin as a promising alternative in therapy of severe difficult-to-treat enterococcal infections.

Bacteraemic spondylodiscitis caused by Enterococcus hirae

Enterococcus hirae infection is extremely rare in humans. In this paper, we describe a case of Enterococcus hirae spondylodiscitis complicated with anterior epidural abscess and multiple psoas abscesses in a 55-year-old man with diabetes mellitus. Despite appropriate antimicrobial therapy, surgery was required. This is the first reported case of spondylodiscitis due to this microorganism. Only two other case reports of human infection by E. hirae are available in the medical literature worldwide.

Adhesion to medical device materials and biofilm formation capability of some species of enterococci in different physiological states

Enterococci may survive in adverse environments including the human body where bacteriocins, antibiotics, iron-limitation and immune response represent stressing conditions for bacteria that cause division block. In those conditions, bacteria present in the human body would hardly be in an exponentially growing phase but would mostly be in physiological states such as starvation or the viable but nonculturable (VBNC) state. The possibility that the starved and VBNC bacteria can maintain their ability to adhere to living and inanimate substrates is the first mandatory step for them potentially to cause an infection process. In this study it is shown that starved and stationary enterococcal cells are able to form biofilms on plastic material albeit with reduced efficiency as compared to growing cells. Moreover, although VBNC enterococcal forms are not capable of forming biofilms, Enterococcus faecalis and other enterococcal species of medical interest maintain their ability to synthesize the polymeric matrix for a limited period of time under adverse environmental conditions. The data presented, together with those regarding the maintenance of the division recovery potential already proved in nonculturable bacteria, further support the possibility for the VBNC and other nondividing bacterial forms to have a role as infectious agents and to constitute a risk to human health.