Antimicrobial susceptibility of Abiotrophia adiacens and Abiotrophia defectiva

Abiotrophia defectiva Endocarditis: A Rare Cause with Aggressive Systemic Embolisation and Need of Valve Replacement

Infective endocarditis (IE) is a well-described infectious disease, one with increased morbidity and mortality being the third or fourth most common life-threatening infection syndrome. Abiotrophia defectiva is a non-motile, catalase negative, gram-positive coccus in a chain, which can be isolated from the oral cavity, intestinal, and genitourinary tracts. IE due to this agent is rare and associated with heart valve destruction, congestive heart failure, and high embolisation rates, these being the major mortality causes. We present a case of IE due to this agent, complicated with a stroke, and splenic and renal infarction, with the need for aortic valve replacement. This article highlights the gaps of knowledge left by the rarity of this disease, which range from its diagnosis to its treatment, and what we need to mitigate such gaps, supported with a case description of a successful treatment of this infection.

LEARNING POINTS

Infective endocarditis due to Abiotrophia defectiva has usually an indolent course, but the embolisation potential is very high.The major causes of mortality with this species are congestive heart failure due to valve destruction and the presence of multiple emboli.Surgical intervention rates are high with Abiotrophia defectiva, reaching 50% of cases.

Granulicatella spp., a Causative Agent of Infective Endocarditis in Children

Granulicatella spp. are non-motile, non-sporulating, facultatively anaerobic Gram-positive cocci. Throughout the literature, these organisms have been referred to by several names, such as “nutritionally deficient streptococci”, “vitamin-B dependent streptococci” and “pyridoxal-dependent streptococci”, because of their fastidious nutritional requirements, which can often make culture isolation challenging. Known to be a member of the normal microbiota of the human oral cavity and urogenital and intestinal tracts, similar to other streptococci, Granulicatella spp. can cause bacteremia, sepsis and infective endocarditis. Considering the difficulty in growing this organism on culture medium, the fact that it is now included among the bacteria known to be responsible for culture-negative infective endocarditis suggests that its pathogenic role could be highly underestimated. Moreover, being considered such a rare causative agent, it is not a target of standard antibiotic empiric treatment. We present a rare case of G. elegans endocarditis in a young child and review the medical literature on Granulicatella endocarditis in the pediatric population, with the aim of sharing knowledge about this microorganism, which can be challenging for a clinician who is not familiar with it.

High prevalence of vancomycin non-susceptible and multi-drug resistant enterococci in farmed animals and fresh retail meats in Bangladesh

The emergence of antimicrobial resistant Enterococcus spp., a main cause of untreatable nosocomial infection, in food animals and dissemination to humans is a public health risk. The study was performed to determine the prevalence and antimicrobial resistance, and virulence characteristics of Enterococcus faecalis and Enterococcus faecium in food animals and meats in Bangladesh. Enterococcus spp., were confirmed using sodA gene specific PCR, and antimicrobial resistance and virulence properties were characterized by PCR. Enterococcus spp. were recovered from 57% of the collected samples (n = 201/352). Farm samples yielded significantly higher (p ≤ 0.05) prevalence (62%) than that of retail meat samples (41%). E. faecalis (52%) is most frequently isolated species. Greater proportions of isolates exhibited resistance to tetracycline (74%), erythromycin (65%) and ciprofloxacin (34%). Fifty-one isolates are vancomycin non-susceptible enterococci (VNSE), of which forty-seven are MDR and twenty are linezolid resistant, a last line drug for VNSE. Virulence factors such as gelatinase (gelE), aggregation factor (asa1) and sex pheromone (cpd) are detected along with vancomycin resistance gene (vanA, vanB and vanC2/C3) in VNSE isolates. The high prevalence of MDR enterococci in food animals and retail meats may cause consumers infections with concomitant reduction of available therapeutic options.

Case Report: Report of Infective Endocarditis Caused by Abiotrophia defectiva and Literature Review

OBJECTIVE

To report the clinical features of the first child with infective endocarditis (IE) caused by Abiotrophia defectiva in mainland China and to raise awareness of the disease.

METHODS

The clinical data of a child with IE caused by A. defectiva admitted to Xi'an Children's Hospital in July 2021 were collected, and the relevant literature was reviewed.

RESULTS

The child was a female, 8 years old, admitted with fever for 4 days and right-sided limb weakness for 3 days. The illness started with suppurative tonsillitis, followed by headache, fatigue, right-sided mouth, slurred speech, right limb weakness, and unstable holding. Transthoracic echocardiography showed that the mitral valve vegetation was formed and vegetation could also be seen at the entrance of the pulmonary vein at the posterior wall of the left atrium. Cranial contrast-enhanced MRI + magnetic resonance angiography showed multiple intracranial pseudoaneurysm formation and pontine infarction. After A. defectiva was detected by metagenomic next-generation sequencing (mNGS) in cerebrospinal fluid and blood detected, the infection was controlled by anti-infective treatment with meropenem and vancomycin. On the 36th day after admission, due to severe headache and slurred speech, the head CT showed hemorrhage of right parietal pseudoaneurysm and cerebral sickle hernia, and right temporo-occipital hematoma evacuation, cerebrovascular malformation resection, and cranial decompression were performed immediately. After the surgery, her speech ability gradually recovered, the muscle strength of her left upper limb was about grade III, while the muscle strength of the rest of the limbs was normal. After a total of 60 days of hospitalization, her family requested to be discharged.

CONCLUSION

This pediatric patient is the first case of childhood IE caused by A. defectiva in mainland China, and the first time in the world that A. defectiva was detected by mNGS in patients with IE.

Lung abscess secondary to lung cancer with a coinfection of Granulicatellaadiacens and other bacteria: a case report

Background

Granulicatella adiacens is facultative anaerobic Gram-positive bacteria, which mainly involve bacterial endocarditis and bacteremia, but there are few reports of local suppurative infection. A case of lung abscess with a coinfection of Granulicatella adiacens and other bacteria in a lung cancer patient will be reported in this paper. To our knowledge, this is the first case report describing lung abscess due to G.adiacens.

Case presentation

A 52-year-old Chinese woman was admitted to the hospital, She complained of coughing and expectoration for 1 month, shortness of breath for half a month, and dyspnea for 1 day. After a series of examinations, she was diagnosed with lung abscess, pleural effusion, and bronchogenic carcinoma. Draining pus culture demonstrated Granulicatella adiacens. After more than 5 weeks of antibiotic therapies in total, she gradually recovered to fight against lung cancer.

Conclusion

This is the first reported lung abscess caused by G.adiacens. In immunosuppressed hosts, G.adiacens is a virulent pathogen associated with a spectrum of intrathoracic suppurative. Earlier diagnosis and proper drainage surgery with effective antibiotics treatment are very important, and antimicrobial treatment should be more than 5 weeks. When complex pulmonary infection interferes with the CT diagnosis, clinical suspicion of lung cancer should be increased if G.adiacens or Eikenella corrodens is detected from a pulmonary infection.

Granulicatella adiacens: An uncommon diagnosis of prosthetic hip joint infection. A case report with review of the literature

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Prosthetic hip infection caused by Granulicatella adiacens.

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Diagnosis was achieved using broad range 16S PCR gene analysis at an early stage, after joint aspiration and culture failed to yield a pathogen.

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Granulicatella adiacens is a nutritionally variant streptococcus (NVS).

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Staged revision surgery together with administration of appropriate antibiotics resulted in cure.

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Diagnosis challenging, and often delays appropriate antibiotic administration.

We report a case of prosthetic hip infection in a 79 year old man caused by Granulicatella adiacens. The diagnosis was achieved using broad range 16S PCR gene analysis at an early stage, after joint aspiration and culture failed to yield a pathogen. Staged revision surgery together with administration of appropriate antibiotics resulted in cure. Granulicatella adiacens is a nutritionally variant streptococcus (NVS). It has been increasingly reported to cause significant morbidities involving various systems. Its insidious growth due to complex growth requirements, has made its diagnosis challenging, and often delays appropriate antibiotic administration.

Atypical presentation of Abiotrophia defectiva infective endocarditis in an octogenarian

Blood cultures should be performed in non-specifically unwell older adults following nonspecific presentations. Prompt diagnosis and commencement of targeted antimicrobial therapy are essential in older patients with A. defectiva IE.

Simultaneous bilateral revision total knee arthroplasty following Abiotrophia defectiva infection

A 65-year old man presented with 6-week history of bilateral knee pain and swelling, with difficulty mobilising. He had bilateral total knee arthroplasties in situ performed 5 years prior complicated by postoperative wound infection. Bilateral synovial fluid cultures were positive for Abiotrophia defectiva, and extensive investigations had not identified an extra-articular source of infection. Failing debridement antibiotic and implant retention procedure, the patient underwent a simultaneous bilateral 2-stage revision with articulated cement spacers impregnated with vancomycin and gentamycin. The patient received 6 weeks of intravenous antibiotics after each stage. A. defectiva is a nutritiously fastidious organism, posing a challenge for clinical laboratories to isolate and perform antimicrobial susceptibility testing, yet prosthetic joint infections caused by A. defectiva are scarce in literature and present atypically with subacute signs of chronic infection. This poses a diagnostic and therapeutic challenge, and two-stage revision is the only documented treatment that successfully eradicates the infection.

Epidemiology, Clinical Features, and Outcome of Infective Endocarditis due to Abiotrophia Species and Granulicatella Species: Report of 76 Cases, 2000-2015

Background

Infective endocarditis (IE) caused by Abiotrophia (ABI) and Granulicatella (GRA) species is poorly studied. This work aims to describe and compare the main features of ABI and GRA IE.

Methods

We performed a retrospective study of 12 IE institutional cases of GRA or ABI and of 64 cases published in the literature (overall, 38 ABI and 38 GRA IE cases).

Results

ABI/GRA IE represented 1.51% of IE cases in our institution between 2000 and 2015, compared to 0.88% of HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella)-related IE and 16.62% of Viridans group streptococci (VGS) IE. Institutional ABI/GRA IE case characteristics were comparable to that of VGS, but periannular complications were more frequent (P = .008). Congenital heart disease was reported in 4 (10.5%) ABI and in 11 (28.9%) GRA cases (P = .04). Mitral valve was more frequently involved in ABI than in GRA (P < .001). Patient sex, prosthetic IE, aortic involvement, penicillin susceptibility, and surgical treatment were comparable between the genera. New-onset heart failure was the most frequent complication without genera differences (P = .21). Five (13.2%) ABI patients and 2 (5.3%) GRA patients died (P = .23). Factors associated with higher mortality were age (P = .02) and new-onset heart failure (P = .02). The genus (GRA vs ABI) was not associated with higher mortality (P = .23).

Conclusions

GRA/ABI IE was more prevalent than HACEK IE and approximately one-tenth as prevalent as VGS; periannular complications were more frequent. GRA and ABI genera IE presented similar clinical features and outcomes. Overall mortality was low, and related to age and development of heart failure.

Native Valve Infective Endocarditis with Osteomyelitis and Brain Abscess Caused by Granulicatella adiacens with Literature Review

Granulicatella adiacens is a type of NVS (nutritionally variant streptococci) rarely causing infective endocarditis (IE). NVS are fastidious and unable to sustain growth on routine culture media due to lack of specific nutrients. Endocarditis caused by NVS due to their virulence is associated with higher treatment failures and mortality rates. New antimicrobial susceptibility patterns are indicative of a significant rise in penicillin resistance and susceptibility differences between NVS subspecies. Initial empirical therapy is essential as a delay in using the appropriate agent leads to poor results. We present a case of an immunocompetent young female with recent intravenous drug abuse resulting in native mitral valve endocarditis with ruptured chordae tendineae and septic embolization, causing brain abscess and lumbar spine osteomyelitis. She was transferred to a tertiary center where she underwent mitral valve replacement successfully and treated with six weeks of intravenous vancomycin and ertapenem. To our knowledge, ours is the first case report of G. adiacens endocarditis in an adult with brain abscess and osteomyelitis with an excellent response to antibiotic therapy. Based on our case report, literature review, and new antimicrobial susceptibility patterns, updates to treatment guidelines are suggested to improve the therapeutic outcomes.

Successful treatment of an acute infective endocarditis secondary to fish bone penetrating into left atrium caused by Granulicatella adiacens and Candida albicans: A case report

RATIONAL

Infective endocarditis caused by a foreign body of the upper digestive tract is rare. We report a rare case of Granulicatella adiacens and Candida albicans coinfection acute endocarditis combined with systematic embolization caused by a fish bone from the esophagus penetrating into the left atrium.

PATIENT CONCERN

A 42-year-old woman was admitted to our hospital because of fever, abdominal pain, headache, and right limb weakness.

DIAGNOSES

Clinical examination indicated endocarditis and systemic embolisms secondary to a fish bone from the esophagus penetrating into the left atrium. The emergency surgery confirmed the diagnosis. Cultures of blood and vegetation show G adiacens and C albicans.

INTERVENTIONS

Antimicrobial therapy lasted 6 weeks after surgery.

OUTCOMES

The patient was discharged with excellent condition7 weeks after hospitalization and was well when followed 6 months later.

LESSONS

The successful treatment of this patient combines quick diagnosis, timely surgery, and effective antimicrobial regimen. This rare possibility should be kept up in mind in acute infective endocarditis cases.

Endocarditis due to Abiotrophia defectiva, a biofilm-related infection associated with the presence of fixed braces: A case report

RATIONALE

Endocarditis with Abiotrophia defectiva represents 4.3% to 6% of all streptococcal endocarditis. The article presents diagnosis issues and the complexity of the treatment.

PATIENT CONCERNS

We present the case of a female white patient, aged 26 years, who developed infectious endocarditis caused by A defectiva, in the last trimester of pregnancy, a biofilm-related infection associated with the presence of fixed braces.

DIAGNOSES

The diagnosis of infectious endocarditis was confirmed by the cardiac ultrasound examination that revealed a voluminous vegetation on the mitral valve, and acute mitral regurgitation caused by chordae tendinae rupture, and also by isolating Abiotrophia defectiva from two positive blood cultures.

INTERVENTIONS

The decision to undergo surgical intervention was taken, and a mitral valve replacement was performed. Surgical intervention that was associated with board-spectrum antibiotic therapy.

OUTCOMES

A defectiva, remains a rare cause of infective endocarditis, with a reserved prognosis that is motivated by the extensive valvular lesions and the risk of embolism.

LESSONS

The use of antibiotics administered in association, in the management of infective endocarditis, is mandatory.

Antimicrobial Susceptibility Patterns among a Large, Nationwide Cohort of Abiotrophia and Granulicatella Clinical Isolates

Antimicrobial susceptibility patterns from 599 A. defectiva, G. adiacens, and G. elegans clinical isolates were determined by broth microdilution. We observed significant differences in susceptibility across species, particularly to penicillin and ceftriaxone, and across geographical regions. A. defectiva was the least susceptible species overall to penicillin. All isolates were susceptible to vancomycin and >90% were susceptible to levofloxacin.

Infective endocarditis due to Abiotrophia defectiva and Granulicatella spp. complicated by infectious intracranial cerebral aneurysms: a report of three cases and review of the literature

Nutritionally variant streptococci, now classified as Abiotrophia defectivaor Granulicatella spp., are thought to account for 2 % of all infective endocarditis cases but estimates of their frequency are complicated by changes in nomenclature and difficulties in obtaining positive microbiology cultures. Their growth characteristics and difficulty undertaking antibiotic susceptibility testing may impede optimal antibiotic treatment decisions. We describe three patients with definite infective endocarditis due to these organisms seen at our hospital between 2005 and 2010, all of whom presented with neurological symptoms due to infectious intracranial cerebral aneurysms. We recommend that, for patients with left-sided infective endocarditis due to A. defictiva and Granulicatella spp., clinicians should consider imaging the central nervous system.

Antimicrobial Susceptibilities of Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella elegans

Nutritionally variant streptococci (NVS) are fastidious Gram-positive cocci comprised of the species Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella elegans. NVS are an important cause of bacteremia and infective endocarditis (IE) associated with significant morbidity and mortality. Antimicrobial susceptibility testing (AST) was performed for 14 antimicrobials using the broth microdilution MIC method described in the Clinical and Laboratory Standards Institute (CLSI) M45 guideline. A total of 132 clinical NVS blood isolates collected from 2008 to 2014 were tested. Species level identification of NVS isolates was achieved by 16S rRNA gene sequencing and/or matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Ninety isolates were identified as G. adiacens, 37 as A. defectiva, and 5 as G. elegans. All isolates were susceptible to vancomycin (MIC90 = 1 μg/ml), and none displayed high-level resistance to aminoglycosides. G. adiacens was considerably more susceptible to penicillin than A. defectiva (38.9% versus 10.8% of isolates susceptible) but was less susceptible to cephalosporins than was A. defectiva (43.3% versus 100% of isolates susceptible to ceftriaxone). Several isolates were resistant to levofloxacin (6%), erythromycin (51%), and clindamycin (10%). The MIC90 for daptomycin was ≥ 4 μg/ml for G. adiacens and A. defectiva. G. elegans isolates were 100% susceptible to all antimicrobials tested, with the exception of erythromycin, to which only 20% were susceptible. This study provides antimicrobial susceptibility data for a recent collection of NVS and demonstrates important NVS species-related differences with respect to susceptibility to penicillin, cephalosporins, carbapenems, and daptomycin. Species-level identification of NVS organisms when susceptibility testing is not readily available may aid in treatment decisions.

Abiotrophia defectiva endocarditis

A previously healthy 27-year-old Jamaican man presented to the University Hospital of the West Indies with recurrent joint pain, remitting and relapsing fever, and shortness of breath. He was subsequently found to have Abiotrophia defectiva endocarditis. This was the first time this organism had been isolated at our institution. Despite culture directed antibiotics, his clinical course was quite severe with mitral regurgitation and congestive cardiac failure requiring mitral valve replacement. He recovered well postoperatively and is currently being followed at our outpatient cardiology clinic. This report highlights the severe presentation and often poor outcome associated with A. defectiva endocarditis and stresses that the outcome may be improved by early and appropriate surgical intervention.

Comparison of MALDI-TOF MS and VITEK 2 system for laboratory diagnosis of Granulicatella and Abiotrophia species causing invasive infections

Granulicatella and Abiotrophia spp. were known as nutritionally variant streptococci (NVS). Such strains have caused major diagnostic difficulties due to fastidious culturing and unspecific colony morphology. The present study is aimed at comparing the performance of laboratory available diagnostic methods for NVS isolates and determining the antimicrobial susceptibility of these isolates. Fourteen clinical invasive isolates, consisting of 10 Granulicatella adiacens, 1 Granulicatella elegans, and 3 Abiotrophia defectiva were in parallel analyzed by 2 matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems, i.e., Bruker MS and Vitek MS, as well as Vitek 2 for the species determination. 16S rRNA gene sequencing was applied as a reference method. The Vitek MS gave correct identification for all 14 isolates. The Bruker MS could correctly identify 8/10 G. adiacens, 0/1 G. elegans, and 3/3 A. defectiva isolates at the first analysis occasion, and all 14 isolates became identifiable after repeated tests. The Vitek 2 system could identify 6/10 G. adiacens, 1/1 G. elegans, and 2/3 A. defectiva isolates at the species level. Antimicrobial susceptibilities of 11 antibiotics were determined by Etest. Resistance against ciprofloxacin, ceftriaxone, rifampicin, and tetracycline were observed in 4, 10, 4, and 1 isolates, respectively. In conclusion, MALDI-TOF MS is a useful tool for the rapid diagnosis of NVS. Phenotypic testing by Vitek 2 is only partially effective for the accurate identification of such strains. The emergence of resistant NVS isolates indicates the necessity of monitoring antimicrobial susceptibilities of such uncommon pathogens.

Infective endocarditis caused by Granulicatella adiacens

Granulicatella adiacens, a recently nomenclatured bacterium, was considered as one of the nutritionally variant streptococci (NVS) and is a mouth commensal. It is redesignated as a streptococcus like bacterium since it differs from streptococci. We report a case of infective endocarditis (IE) caused by this fastidious and unusual bacteria in a 63-year-old man with rheumatic valvular heart disease. G. adiacens was isolated from four of his blood culture samples, which was sensitive to beta lactams, moderately sensitive to gentamicin and resistant to erythromycin and co-trimoxazole. Patient recovered completely on treatment with high dose of ampicillin and gentamicin for 28 days.

Granulicatella bacteraemia in children: two cases and review of the literature

Background

Granulicatella spp. is a fastidious bacteria responsible for bacteremia and endocarditis which are fatal in about 20% of the cases. These severe infections are uncommon in children under 17 years of age and have proven extremely difficult to treat.

Cases presentation

We report a brief review of the literature and two cases of NVS bacteremia by Granulicatella complicated by infective endocarditis (IE). The first one is that of a 7-year-old Caucasian female with Shone syndrome and IE involving the pulmonary valve homograft, confirmed by echocardiography. The second case is that of a 5-year-old Caucasian male. In this patient echocardiogram was negative for signs of IE; however, a “possible” IE was suspected on the basis of a cardiac catheterization 3 weeks before the onset of fever. Since in both our patients clinical failure of first line antibiotic treatment was observed, we used a combination of meropenem with another anti-streptococcal drug with excellent results.

Conclusion

In Granulicatella bacteremia in the pediatric population, combination antimicrobial therapy including meropenem should be considered as a second line treatment in non-responding patients.

Intravascular catheter-related bloodstream infection caused by Abiotrophia defectiva in a neutropenic child

Bacteraemia and endocarditis are the most frequently reported clinical infections due to Abiotrophia defectiva species. This species has been rarely implicated in infections in neutropenic patients. We report a rare case of long-term venous catheter-related infection caused by A. defectiva that occurred in a febrile child who had neutropenia and Langerhans' cell histiocytosis.

Meningitis caused by Abiotrophia defectiva: case report and literature review

The genus Abiotrophia comprises fastidious Gram-positive bacteria previously classified as nutritionally variant streptococci (NVS). The isolation of NVS from the central nervous system (CNS) is very rare. We describe a case of meningitis due to Abiotrophia defectiva in a patient who underwent a total hip arthroplasty 4 days previously. It is possible that the organism could be introduced through the spinal anesthesia. We also review all cases of CNS infections caused by NVS.

Granulicatella infection: diagnosis and management

Granulicatella species, along with the genus Abiotrophia, were originally known as 'nutritionally variant streptococci'. They are a normal component of the oral flora, but have been associated with a variety of invasive infections in man and are most noted as a cause of bacterial endocarditis. It is often advised that Granulicatella endocarditis should be treated in the same way as enterococcal endocarditis. We review here the published data concerning diagnosis and treatment of Granulicatella infection, and include some observations from local cases, including four cases of endocarditis.

Comparative molecular and microbiological diagnosis of 19 infective endocarditis cases in which causative microbes were identified by PCR-based DNA sequencing from the excised heart valves

Infective endocarditis (IE) is traditionally diagnosed by microbiological analysis of blood cultures, following which therapeutic antibiotics are chosen based on antimicrobial sensitivity tests. However, such conventional techniques do not always lead to an accurate etiological diagnosis. Recently, PCR analysis of the 16S rRNA gene has been employed to identify organisms isolated from excised heart valves. In this study, we analyzed 19 valve samples from patients with confirmed IE, as identified by Duke's criteria. Using broad-range PCR amplification, followed by direct gene sequencing, pathological agents were identified in all samples. Although blood cultures yielded negative results in 4 cases, PCR analysis of valve samples showed positive identification of causative organisms. In 3 cases, there was a difference between blood culture and PCR in identification of pathological agents, which are likely to be misidentified by the conventional method based on the phenotypic database. Postoperative antibiotics were chosen considering the severity of lesions and the results of PCR, Gram staining, and valve cultures. All patients were cured without relapse. The broad-range PCR method was therefore beneficial for the management of IE because it enabled us to identify pathogens directly from the site of infection, even organisms that were difficult to culture or likely to be misidentified by the conventional culture method. Identification of the agents provided precise knowledge of the microbiological spectrum involved in the cases of IE.

An unusual causative agent for an orbital abscess: Granulicatella Adiacens

We present a patient who developed an orbital abscess secondary to a retained organic (wooden) foreign body after a fall. Clinically, he had a right sub brow fistula exuding purulent discharge, four millimetres of proptosis, limitation of ocular motility in all directions of gaze, but no signs of optic neuropathy. Preoperative computed tomography and magnetic resonance imaging of the orbits was performed to localise the abscess and to facilitate surgical planning. He underwent exploration, drainage of the abscess and removal of the wooden foreign body with good postoperative recovery. Cultures isolated Ganulicatella Adiacens, a nutritionally variant streptococcus. This is an unusual causative organism and to our knowledge, this is the first reported case of a posttraumatic orbital abscess associated with Granulicatella Adiacens. Clinical suspicion, isolation of the organism and appropriate microbial treatment requires a multidisciplinary approach, with input from the ophthalmologist, microbiologist and infectious disease team. This will ensure a good outcome in patient management.

Granulicatella adiacens bacteremia in an elderly trauma patient

BACKGROUND

Granulicatella adiacens is a normal commensal of human mucosal surfaces, inhabiting the oral cavity and urogenital and gastrointestinal tracts and only rarely causing disease. These gram-positive cocci can be difficult to identify.

CASE REPORT

We report a first case of bacteremia caused by Granulicatella adiacens in an elderly female trauma victim. The infection was diagnosed accurately, and the patient was treated successfully.

CONCLUSION

Granulicatella adiacens may be a more important pathogen than thus far recognized because of a lack of adequate diagnostic resources. Standards for sensitivity testing are needed urgently.

Use of groESL as a target for identification of Abiotrophia, Granulicatella, and Gemella species

We determined the groESL sequences of three species of nutritionally variant streptococci (Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella elegans) and three Gemella species (Gemella morbillorum, Gemella haemolysans, and Gemella sanguinis). The nucleotide sequence similarities between the groES and groEL genes of the above genera were 41.7 to 85.9% and 63.7 to 84.3%, respectively. The intraspecies similarities of groESL sequences for the isolates of Abiotrophia and Granulicatella species were 94.4 to 97.8% for groES and 94.0 to 98.2% for groEL. For Ge. morbillorum and Ge. sanguinis, all strains showed the same groESL spacer length (8 bp), and sequence identities within species were >97.8% for groES and >96.1% for groEL. However, higher intraspecies heterogeneity was observed in Ge. haemolysans. Phylogenetic analysis of groEL sequences separated the 6 isolates of Ge. haemolysans into two subgroups. Among these isolates, three isolates with the same groESL spacer region length (45 bp) clustered together but were distant from the ATCC reference strain (with a spacer length of 8 bp). The remaining three isolates, with a spacer length of 50 or 8 bp, clustered together. Although 16S rRNA gene sequence analysis did not provide enough discrimination for the 6 Ge. haemolysans isolates, rpoB gene sequence analysis supported the subgrouping. Based on the obtained groESL sequences, we developed a multiplex PCR that enables simple, rapid, and accurate identification of Abiotrophia, Granulicatella, and Gemella at the genus level. This assay would be helpful for identifying these fastidious and slow-growing organisms in clinical laboratories.

Medical treatment of endocarditis

Infective endocarditis (IE) remains a serious and deadly disease. The incidence, which varies by gender and on the presence of predisposing factors, has not decreased, due in part to the aging population with more healthcare exposures and predisposing risk factors such as prosthetic heart valves and intracardiac devices. The most important aspects of treatment in IE hinge upon early diagnosis, microorganism identification with susceptibility testing, and early initiation of appropriate antibiotic therapy. In addition, echocardiographic imaging is critical for both diagnostic and prognostic purposes. Early evaluation for surgery should be considered. Once a therapeutic strategy is begun, careful attention to the clinical course is necessary to ensure appropriate response to therapy and to identify complications early.

Fluorescence in situ hybridisation (FISH) accelerates identification of Gram-positive cocci in positive blood cultures

Sepsis is a life-threatening disease with a high mortality rate. Rapid identification of blood culture isolates plays a crucial role in adequate antimicrobial therapy in sepsis patients. To accelerate microbiological diagnosis, a comprehensive panel of oligonucleotide probes for fluorescence in situ hybridisation (FISH) targeting Gram-positive cocci was compiled and evaluated on 428 positive blood culture specimens. By combining genus-specific and species-specific probes, the assay allowed discrimination of staphylococci, streptococci and enterococci as well as differentiation of therapy-relevant pathogens such as Staphylococcus aureus and Enterococcus faecium/durans. Furthermore, the newly designed FISH probes STREP2, ENCO and GRANU targeted Streptococcus pneumoniae/mitis, Enterococcus spp. (except E. faecalis) and Granulicatella adiacens group, respectively. The FISH assay achieved an overall sensitivity of 98.65% and a specificity of 99.0% and therefore allowed rapid and reliable molecular identification of Gram-positive cocci in blood culture specimens.

Catonella morbi and Granulicatella adiacens: new species in endodontic infections

OBJECTIVE

This study intended to examine samples from primary endodontic infections for the presence of Catonella morbi and Granulicatella adiacens, 2 species that have been recently suggested to be involved with infections in other oral sites.

STUDY DESIGN

Genomic DNA was isolated directly from samples taken from teeth with different forms of apical periodontitis, and a devised culture-independent 16S rRNA gene-based heminested PCR assay was used to determine the prevalence of these 2 target species. Species-specific primers were developed by aligning closely related 16S rRNA gene sequences. Species-specificity for each primer pair was confirmed by running PCR against a panel of oral bacteria and by sequencing of DNA from representative positive samples.

RESULTS

C morbi and G adiacens were detected in 33% and 19%, respectively, of the root canals associated with chronic apical periodontitis; 30% and 10%, respectively, of the cases diagnosed as acute apical periodontitis, and 16% and 11%, respectively, of the pus samples taken from acute apical abscesses. Overall, C morbi occurred in 26% and G adiacens in 14% of the samples taken from primary endodontic infections.

CONCLUSIONS

Our findings demonstrate that C morbi and G adiacens can take part in the microbiota associated with primary endodontic infections, and their specific role in the disease process warrants further elucidation.

Bloodstream and endovascular infections due to Abiotrophia defectiva and Granulicatella species

BACKGROUND

Abiotrophia and Granulicatella species, previously referred to as nutritionally variant streptococci (NVS), are significant causative agents of endocarditis and bacteraemia. In this study, we reviewed the clinical manifestations of infections due to A. defectiva and Granulicatella species that occurred at our institution between 1998 and 2004.

METHODS

The analysis included all strains of NVS that were isolated from blood cultures or vascular graft specimens. All strains were identified by 16S rRNA sequence analysis. Patients' medical charts were reviewed for each case of infection.

RESULTS

Eleven strains of NVS were isolated during the 6-year period. Identification of the strains by 16S rRNA showed 2 genogroups: Abiotrophia defectiva (3) and Granulicatella adiacens (6) or "para-adiacens" (2). The three A. defectiva strains were isolated from immunocompetent patients with endovascular infections, whereas 7 of 8 Granulicatella spp. strains were isolated from immunosuppressed patients, mainly febrile neutropenic patients. We report the first case of "G. para-adiacens" bacteraemia in the setting of febrile neutropenia.

CONCLUSION

We propose that Granulicatella spp. be considered as a possible agent of bacteraemia in neutropenic patients.

Prosthetic valve endocarditis from Granulicatella adiacens (nutritionally variant streptococci)

Nutritionally variant streptococci (NVS) are an unusual but significant cause of endocarditis, with increased morbidity and mortality compared to those caused by enterococci or viridans streptococci. For many reasons, NVS endocarditis has remained very difficult to treat medically with antibiotics, and when the bacteria infect prosthetic valves, surgical intervention has historically been required to effect cure. We report the first case of Granulicatella adiacens prosthetic valve endocarditis (PVE) in a patient with congenital heart disease who was successfully treated with a regimen of vancomycin, gentamicin, and rifampin and provide the first review of the literature on NVS PVE, as well as discussion of logistics behind the use of this antibiotic regimen.

Infective endocarditis caused by Granulicatella elegans originating in the oral cavity

We studied the pheno- and genotypes of an oral Granulicatella elegans strain in comparison with those of a blood-derived isolate which caused infective endocarditis. The two isolates exhibited identical biochemical characteristics and had the same drug MICs. Their genotypes were indistinguishable, indicating that these were from the same clone. The transmission of G. elegans from the oral cavity thus should be noted as a possible cause of infective endocarditis.

A woman with infectious endocarditis caused by Abiotrophia defectiva

A 74-year-old woman with recurrent fever and multiple joint pain was admitted to Hokkaido University Hospital. Trans-esophageal echocardiogram revealed bacterial vegetation and destruction of the aortic valve. Although few bacteria grew in regular blood agar, Gram-positive coccobacillus was specifically grown in chocolate blood agar and Brucella agar, and it was identified to be Abiotrophia defectiva. Infectious endocarditis caused by Abiotrophia defectiva was diagnosed, she was treated with diuretics, penicillin G and gentamicin, and she immediately improved. Infectious diseases caused by Abiotrophia defectiva are extremely rare, and identification of this pathogen is important, as its bacterial characteristics require proper attention.

Antimicrobial susceptibilities of invasive pediatric Abiotrophia and Granulicatella isolates

Abiotrophia and Granulicatella species have been associated with various infections. Antimicrobial susceptibility data for these nutritionally variant streptococcus-like organisms, especially for pediatric isolates, are very limited. Little is known about the genetic bases of their resistance mechanisms. We report the results of identification to bacterial species level, antimicrobial susceptibility testing, macrolide resistance testing, and detection of genes encoding that resistance for a collection of 15 pediatric clinical isolates from normally sterile sites. Our results indicate that the prevalence of beta-lactam and macrolide resistance is high and that both erm and mef are found in these isolates.

Central nervous system infections due to Abiotrophia and Granulicatella species: an emerging challenge?

Although Abiotrophia and Granulicatella species, previously referred to as nutritionally variant streptococci, were initially identified over 40 years ago, isolation of these pathogens from the central nervous system (CNS) was first noted only recently. Recognition of CNS involvement with these organisms is of great concern given the association of Abiotrophia/Granulicatella infections with increased morbidity and mortality as well as greater bacteriologic failure and relapse rates. We describe A. defectiva and G. adiacens CNS infections in two patients and review the existing literature of CNS involvement with these bacteria. The clinical presentation and initial cerebrospinal fluid analysis has varied substantially across reported patients. While most infections have been characterized primarily by a localized infection (e.g., abscess), evidence of meningitis has usually also been present. Furthermore, nearly all cases have followed neurosurgical procedures suggesting possible introduction of the organism into the CNS at the time of surgery. Given the significant negative clinical impact of Abiotrophia/Granulicatella infections, elucidation of the emerging epidemiology of CNS infections with these bacteria is warranted.

Aortitis in a child with Abiotrophia defectiva endocarditis

Abiotrophia defectiva, one of several nutritionally variant Streptococcus species, is an uncommon but important cause of endocarditis in children. We describe an unusual case complicated by extensive aortitis with pits in the ascending aorta and the proximal aortic arch.

Nutritionally variant streptococcal infections at a University Hospital in Taiwan: disease emergence and high prevalence of beta-lactam and macrolide resistance

From January 1993 to December 2002, 28 patients with nutritionally variant streptococci (NVS) infections were treated at a university hospital in Taiwan. Twelve (43%) of these patients had various underlying malignancies, and 7 (25%) had underlying valvular heart diseases. Nine patients (32%) had infective endocarditis, and 9 (32%) had primary bacteremia. The deaths of 7 patients (25%) were directly related to NVS infection. Among the 28 isolates recovered from these patients, 50% were not susceptible to penicillin, 33% were not susceptible to cefotaxime, and 93% were not susceptible to azithromycin.