Abiotrophia species as a cause of endophthalmitis following cataract extraction

Abiotrophia defectiva Endophthalmitis Post-Keratoplasty - A Case Report and Literature Review

PURPOSE

To report the first case of acute Abiotrophia defectiva endophthalmitis post-keratoplasty and review the current literature.

METHODS

A 47-year-old male, post-keratoplasty, presented with vision loss and severe anterior chamber reaction. Diagnostic investigations included vitreous cultures and molecular analysis.

RESULTS

Abiotrophia defectiva was identified. Despite aggressive treatment, visual acuity remained low. We reviewed a total of 14 post-procedural cases of A. defectiva endophthalmitis, focusing on antibiotic and steroidal treatment regimens and long-term prognosis.

CONCLUSION

We emphasize aggressive treatment of external disease prior to intraocular surgery. In cases of A. defectiva endophthalmitis, we advocate judicious use of steroids.

RARE CASE OF ABIOTROPHIA DEFECTIVA BLEB-ASSOCIATED ENDOPHTHALMITIS

PURPOSE

To report a rare case of Abiotrophia defectiva bleb-associated endophthalmitis.

METHODS

In this case report of a patient with bleb-associated endophthalmitis, the authors describe the features of severe and rapid onset, associated retinitis, and a favorable outcome after aggressive early intervention.

RESULTS

A 75-year-old woman presented decreased visual acuity of hand motions with an elevated intraocular pressure of 39 mmHg in the left eye. Her ocular history was notable for severe primary open-angle glaucoma with uneventful trabeculectomy and cataract surgery in both eyes 7 years before. Examination revealed conjunctival injection and an opaque avascular cystic bleb along with anterior chamber cellular reaction with a B-scan ultrasound concerning for vitritis. A. defectiva was isolated from the vitreous tap within 48 hours and confirmed later with 16S ribosomal RNA sequencing. After initial vitreous tap and inject and subsequent pars plana vitrectomy, her best-corrected visual acuity had improved to 20/500 at postoperative week one and then improved to 20/40 at postoperative month 2. Her examination was notable for resolved corneal edema, a deep and quiet anterior chamber, and resolved intraretinal hemorrhages.

CONCLUSION

This is one of the first bleb-associated endophthalmitis cases with rapid identification of A. defectiva . A. defectiva was isolated from the initial vitreous tap within 48 hours and confirmed with 16S ribosomal RNA sequencing. This case highlights that rapid identification of A. defectiva may be indicative of a greater bacterial load and should prompt aggressive intervention and that the visual prognosis can be favorable.

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.

Granulicatella elegans infective endocarditis: A case report

Granulicatella elegans is a rare cause of infective endocarditis, accounting for 1–2% of all cases. It is well recognized that this pathogen can present in association with negative blood cultures. There are higher rates of both relapse and mortality compared with endocarditis caused by other bacteria. Microbiological diagnosis can be especially challenging because many conventional blood culture media lack pyridoxal, which can be found in automated blood culture broths like BACTEC™ or BACT/ALERT® and thus they may require ‘helper’ bacteria to be culture the organism. This current case report describes a 66-year-old male patient with a 10-year history of post-inflammatory combined aortic valve disease (moderate aortic stenosis and mild aortic regurgitation). He presented with a 3-month history of recurrent fever and general deterioration. Despite targeted, prolonged, combined antibiotic treatment with intravenous penicillin and gentamicin, surgery was eventually required. An aortic prosthetic valve implantation was performed with good results. In case of subacute endocarditis, especially when a causative organism proves difficult to detect, G. elegans should be considered. Identification is greatly enhanced by using polymerase chain reaction methods and this test should be considered in all cases of culture negative endocarditis.

Abiotrophia Causing Prosthetic Joint Septic Arthritis

A 71-year-old Caucasian male with a past medical history of Charcot-Marie-Tooth disease type 2 presented to our rural hospital for left knee pain, swelling, and difficulty walking. The patient had prior bilateral total knee replacements with a subsequent left knee revision due to infection. Joint aspiration was culture-positive and 16S recombinant DNA (rDNA) sequence positive for Abiotrophia defectiva. The patient underwent a left total knee extraction with a temporary antibiotic spacer insertion. On discharge, the patient received an initial six weeks of ceftriaxone 2g IV. At the outpatient six-week follow-up, the patient was cleared of the Abiotrophia infection. However, later complications and a subsequent Enterobacter cloacae infection arose.

CASE REPORT OF ABIOTROPHIA DEFECTIVA ENDOPHTHALMITIS AFTER REPEATED INJECTIONS OF DEXAMETHASONE INTRAVITREAL IMPLANT (OZURDEX)

PURPOSE

To present a case of endophthalmitis caused by Abiotrophia defectiva after repeated injections of dexamethasone intravitreal implant (Ozurdex), in a patient already on systemic immunosuppressive therapy, and discuss the management of this challenging situation.

METHODS

Case report and review of literature.

RESULTS

A 70-year-old female patient with history of idiopathic pulmonary fibrosis presented for urgent evaluation due to left eye vision loss and mild discomfort 12 days after receiving her seventh dexamethasone implant injection. Ocular history was pertinent for recurrent macular edema resulting from a remote branch vein occlusion. Twelve days after her last injection, visual acuity decreased from 20/30 to counting fingers at 5 feet. Slit-lamp examination showed anterior chamber cell without fibrinoid membranes or hypopyon. Within hours, the patient's clinical appearance progressed. A vitreous tap followed by intravitreal injection of vancomycin (1 mg/0.1 mL) and ceftazidime (2.25 mg/0.1 mL) was performed. The culture from the vitreous sample revealed heavy growth of A. defectiva. Owing to limited improvement, patient was taken to the operating room, and the presence of a full-thickness scleral defect at the site of most recent dexamethasone implant injection was confirmed. Vitrectomy with removal of implant, closure of all sclerotomies, including nonhealing full-thickness scleral defect, and repeated intravitreal antibiotic injection were performed. At the 3-month follow-up, no inflammation was observed, but visual acuity remained poor.

CONCLUSION

Intravitreal dexamethasone implant-associated endophthalmitis in the setting of systemic immunosuppression is a rare and challenging situation. Both local and systemic immunosuppression may delay wound healing, predisposing to wound leakage and consequent endophthalmitis. Despite repeated intravitreal antimicrobial injection and vitrectomy with implant removal, A. defectiva endophthalmitis carried a poor visual outcome.

Granulicatella adiacens endophthalmitis after phacoemulsification cataract surgery

Two cases of acute postoperative Granulicatella adiacens endophthalmitis following uneventful phacoemulsification surgery are reported. The cases had intracameral cefuroxime as antibiotic prophylaxis, visual acuity (VA) was perception of light and hand movements, respectively, and there was severe anterior chamber inflammation and dense vitritis with no fundal view. Vitreous biopsy identified G adiacens using genome sequencing. Intraoperative findings included extensive retinal hemorrhages, abscesses, occluded retinal vessels, and retinal necrosis. Because of the ischemic retinal appearance, pan-retinal photocoagulation endolaser was performed. Postoperatively both cases developed rhegmatogenous retinal detachment (RRD) anterior to the laser marks and were successfully treated. VA improved to 6/18 and 6/60, respectively. Hyperreflective dots and Henle fiber layer hemorrhage are reported for the first time, to the authors' knowledge, in association with endophthalmitis. The successful outcome suggested that intraoperative pan-retinal photocoagulation could be considered in such ischemic cases to prevent rubeosis and to reduce the risk for postoperative RRD or limit its extent if it recurs.

Trends in Endophthalmitis Associated With Intravitreal Injection of Anti-VEGF Agentsat a Tertiary Referral Center

BACKGROUND AND OBJECTIVE

To report the incidence and clinical features of infectious endophthalmitis after intravitreal (IV) injection of anti-vascular endothelial growth factor inhibitors (VEGF) between 2018 and 2020 and to compare to prior rates.

PATIENTS AND METHODS

Retrospective analysis of patients with endophthalmitis after anti-VEGF IV injections treated at Bascom Palmer Eye Institute between January 1, 2018, and December 31, 2020.

RESULTS

Between 2018 and 2020, the rate of clinically diagnosed endophthalmitis was 0.014% (10/71,858) and of culture-positive was 0.008% (6/71,858). Clinically diagnosed endophthalmitis rates per injection were: aflibercept (0.022%); ranibizumab (0.019%); bevacizumab (0%); and brolucizumab (0%). Clinically diagnosed endophthalmitis rates were similar in the present study compared to those from 2005 to 2017 (P = .84). Fifteen eyes were diagnosed with endophthalmitis (10 in-house, five external referrals). Of culture-positive eyes, the organisms were coagulase-negative Staphylococcus (8/11), Streptococcus species (2/11), and Abiotrophia defectiva (1/11). A universal face-masking policy in 2020 did not lower infection rates (P = .73).

CONCLUSION

Endophthalmitis rates after IV anti-VEGF remain low and are similar to prior reports. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:319-326.].

Nutritionally variant streptococci causing endophthalmitis associated with intravitreal anti-vascular endothelial growth factor injection

Purpose

To describe the clinical course and microbial properties of the first two reported cases of nutritionally variant Streptococci (Granulicatella adiacens and Abiotrophia defectiva) endophthalmitis following intravitreal anti-vascular endothelial growth factor injection (IVI).

Observations

A 74 year-old female developed Granulicatella adiacens endophthalmitis following IVI. The patient underwent a pars plana vitrectomy and visual acuity recovered to 20/30 in six weeks. Similarly, an 88 year-old male developed Abiotrophia defectiva endophthalmitis after IVI. After a pars plana vitrectomy, the visual acuity recovered to 20/60 at five weeks.

Conclusions and Importance

Endophthalmitis due to Streptococcus species has traditionally resulted in uniformly poor visual outcomes. However, nutritionally variant Streptococci, now reclassified as Granulicatella and Abiotrophia species, appear to have a less aggressive clinical course and better visual acuity outcomes. To the authors’ knowledge, these are the first reports of nutritionally variant Streptococci following IVI related endophthalmitis.

Granulicatella Adiacens as an Unusual Cause of Microbial Keratitis and Endophthalmitis: A Case Series and Literature Review

Purpose: To report two cases of microbial keratitis and/or endophthalmitis involving Granulicatella adiacens.Methods: Case series.Results: 24-year-old female with a history of Herpes simplex virus 1 (HSV-1) and Candida parapsilosis keratitis presented with a geographic epithelial defect and infiltrate in the left eye. Cultures were positive for HSV-1 and G. adiacens. Keratitis resolved with topical vancomycin and oral valacyclovir. A 65-year-old female with a history of type II diabetes and failed therapeutic penetrating keratoplasty presented with inferior corneal graft haze and vitreous inflammation of the right eye. Therapeutic penetrating keratoplasty and pars plana vitrectomy were performed, and the corneal button returned positive for G. adiacens. The patient was treated with topical and intravitreal vancomycin as well as topical and systemic steroids.Conclusions: These cases expand the literature on G. adiacens keratitis and endophthalmitis and corroborate the role of steroid use and prior surgery as paramount risk factors.

[Endophthalmitis after perforation of the conjunctiva by a glaucoma gel-stent implant]

Intraokulare Infektionen durch Abiotrophia defectiva sind sehr selten. Hier berichten wir von einer 57-jährigen Patientin, welche sich 3 Monate nach erfolgter komplikationsloser Kataraktoperation mit Implantation eines Glaukom-Gelstents am rechten Auge mit einer Abiotrophia-defectiva-assoziierten Endophthalmitis bei uns vorstellte. Die Patientin klagte zuvor über eine Rötung im Bereich der nasal oberen Bindehaut des rechten Auges sowie über Schmerzen 2 Wochen vor Auftreten der Endophthalmitis. Eine 2‑wöchige topische Steroidtherapie ohne Antibiotikaschutz brachte eine kurzfristige Besserung. Die Patientin stellte sich nun bei uns mit einem Hypopyon, einer akuten Visusverschlechterung und starken periokulären Schmerzen seit dem frühen Morgen vor. Der Gelstent hatte spontan die Konjunktiva perforiert. Es erfolgte die unmittelbare Therapie mit lokaler und systemischer Antibiose. Sechs Stunden danach wurde eine Pars-plana-Vitrektomie mit intraokularer Gabe von Antibiotika durchgeführt. Durch eine zeitnahe Therapie konnte in diesem Fall ein relativ benigner Verlauf erreicht werden. Im klinischen Alltag sollte bei Patienten, die sich nach glaukomchirurgischen Eingriffen mit akuter Visusverschlechterung und Schmerzen präsentieren, dringend an eine mögliche spontane Bindehautperforation und Late-onset-Endophthalmitis gedacht werden. Zudem ist zu empfehlen, dass eine unklare Konjunktivitis nach Glaukomchirurgie immer antibiotisch abgedeckt und engmaschiger kontrolliert werden sollte.

Endophthalmitis Caused by Abiotrophia Defectiva after Anterior Vitrectomy in a Child

Endophthalmitis caused by Abiotrophia defectiva has never before been reported in a child. We report a case of a 12-year-old female with a history of penetrating keratoplasty, followed years later by open globe injury and repair, and subsequent anterior vitrectomy, which resulted in endophthalmitis caused by Abiotrophia defectiva. We review previous cases of endophthalmitis by this organism and argue that its detection will become more common with the use of 16S rDNA PCR and MALDI-TOF mass spectrometry.

Abiotrophia defectiva endophthalmitis following routine cataract surgery: the first reported case in the United Kingdom

Introduction

Abiotrophia defectiva is a fastidious organism that has been implicated in severe infections such as endocarditis in immunocompetent patients. Modern tools are available to aid identification, but the main challenge remains clinical suspicion of A. defectiva.

Case presentation

An otherwise fit and well 65-year-old female presented with reduced vision, red eye and discomfort 2 days following routine left cataract surgery. She had visual acuity of light perception only, significant anterior chamber inflammation (including hypopyon) and limited fundal view. She was diagnosed with post-operative endophthalmitis and 0.1 ml of ceftazidime (2 mg/0.1 ml) and 0.1 ml vancomycin (2 mg/0.1 ml) were injected intravitreally after vitreous aspiration. Subconjunctival cefuroxime was also injected. A repeat injection was performed on day three of admission. Gram staining revealed Gram-positive long-chain cocci, which were identified as A. defectiva. The patient was discharged on oral ciprofloxacin 500 mg twice a day with oral prednisolone 60 mg once a day; this was tapered and stopped at 8 weeks post-discharge. The left eye received dexamethasone 0.1 % 6 times a day (again, tapered over 8 weeks), moxifloxacin 5 % 6 times a day and atropine 1 % twice a day. Vision improved to 6/12 unaided (6/9.5 with pinhole) at 9 weeks post-operatively, with a clear fundal view.

Conclusion

We present a case of A. defectiva endophthalmitis following routine cataract surgery. To our knowledge, this is the first reported case in the UK and the fourth globally, which with prompt treatment ended with a good visual outcome.

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.

Successful treatment of periprosthetic joint infection caused by Granulicatella para-adiacens with prosthesis retention: a case report

BACKGROUND

Granulicatella and Abiotrophia spp. are difficult to detect due to their complex nutritional requirements. Infections with these organisms are associated with high treatment failure rates. We report the first implant-associated infection caused by Granulicatella para-adiacens, which was cured with anti-microbial treatment consisting of anti-biofilm-active rifampin and debridement, exchange of mobile parts and retention of the prosthesis.

CASE PRESENTATION

Patient with a history of left hip arthroplasty presented with acute onset of fever, pain and limited range of motion of the left hip. Arthrocentesis of the affected joint yielded purulent fluid and exchange of mobile parts of the prosthesis, but retention of fixed components was performed. Granulicatella para-adiacens grew from preoperative and intraoperative cultures, including sonication fluid of the removed implant. The transesophageal echocardiography showed a vegetation on the mitral valve; the orthopantogram demonstrated a periapical dental abscess. The patient was treated with intravenous penicillin G and gentamicin for 4 weeks, followed by levofloxacin and rifampin for additional 2 months. At discharge and at follow-up 1, 2 and 5 years later, the patient was noted to have a functional, pain-free, and radiologically stable hip prosthesis and the serum C-reactive protein was normal.

CONCLUSIONS

Although considered a difficult-to-treat organism, we report a successful treatment of the Granulicatella hip prosthesis infection with prosthesis retention and a prolonged antibiofilm therapy including rifampin. The periapical dental abscess is considered the primary focus of hematogenously infected hip prosthesis, underlining the importance treatment of periodontitis prior to arthroplasty and of proper oral hygiene for prevention of hematogenous infection after arthroplasty.

Postkeratoplasty Keratitis Caused by Abiotrophia defectiva: An Unusual Cause of Graft Infection

Abiotrophia defectiva is a nutritional variant of Streptococci. We describe a case of microbial keratitis due to A. defectiva in a patient who had undergone penetrating keratoplasty and was on corticosteroid therapy for recent graft rejection. Isolation of this organism confirmed this to be an opportunistic infection.

Nutritionally variant streptococci bacteremia in cancer patients: a retrospective study, 1999-2014

BACKGROUND

Nutritionally variant Streptococci (NVS), Abiotrophia and Granulicatella are implicated in causing endocarditis and blood stream infections more frequently than other sites of infection. Neutropenia and mucositis are the most common predisposing factors for infection with other pathogens in cancer patients. In this study, we investigated the clinical characteristics of NVS bacteremia in cancer patients and identified risk factors and outcomes associated with these infections.

MATERIALS AND METHODS

We retrospectively reviewed all cases of NVS bacteremia occurring from June 1999 to April 2014 at H. Lee Moffitt Cancer Center and Research Institute. The computerized epidemiology report provided by the microbiology laboratory identified thirteen cancer patients with NVS bacteremia. We collected data regarding baseline demographics and clinical characteristics such as age, sex, underlying malignancy, neutropenic status, duration of neutropenia, treatment, and outcome.

RESULTS

Thirteen patients were identified with positive NVS blood stream infection. Ten patients (77%) had hematologic malignancies, including chronic lymphocytic leukemia (CLL)(1), multiple myeloma (MM)(1), acute myelogenous leukemia (AML)(4), and non-Hodgkin's lymphoma (NHL)(4). The non-hematologic malignancies included esophageal cancer(2) and bladder cancer (1).

CONCLUSION

NVS should be considered as a possible agent of bacteremia in cancer patients with neutropenia and a breach in oral, gastrointestinal and genitourinary mucosa (gingivitis/mucositis).

Survey of intravitreal injection techniques and treatment protocols among retina specialists in Canada

OBJECTIVE

To describe intravitreal injection (IVI) techniques and treatment protocols by retina specialists in Canada from August 1, 2012, to October 1, 2012.

DESIGN

Cross-sectional survey.

PARTICIPANTS

All fellowship-trained retina specialists across Canada, as identified from the Canadian Ophthalmological Society directory and the Canadian Retina and Vitreous Society directory.

METHODS

An anonymous 28-question survey was sent to 125 retina specialists across Canada by email. Reminder letters were sent by email, mail, and fax as necessary.

RESULTS

A total of 75 (63%) retina specialists responded to the survey. Most IVIs were performed in the office. Most surgeons did not use gloves (61%), sterile draping (91%), or surgical mask (71%). Antisepsis was used on conjunctiva by 100% and on periocular skin by 48%. Nearly all specialists used a sterile lid speculum (91%). Common anaesthetics included topical proparacaine or lidocaine drops (90%), topical lidocaine gel (25%), topical pledget (23%), and subconjunctival lidocaine injections (23%). Most (83%) dilate the pupil before IVI. Prophylactic topical antibiotics were used by 43%; 50% of these were started immediately after IVI. Injection location was estimated by visualization by 45%. A majority (63%) inject inferotemporally. Anterior chamber paracentesis was performed routinely by 5%. Optic nerve perfusion was formally assessed by 48%. The most common treatment protocol for age-related macular degeneration was treat and extend. For both diabetic and retinal vein occlusion-related macular edema, the most common protocol was 3 initial monthly injections with PRN follow-up.

CONCLUSIONS

A wide variety of IVI practice patterns exist in terms of aseptic technique, anaesthetics, prophylactic antibiotics, postinjection monitoring, and treatment protocol.

Reducing oral flora contamination of intravitreal injections with face mask or silence

PURPOSE

To provide experimental evidence to support or refute the proposition that the use of surgical face masks and/or avoidance of talking can decrease the dispersion of respiratory flora during an intravitreal injection.

METHODS

Ten surgeons recited a 30-second standardized script with blood agar plates positioned 30 cm below their mouths. The plates were divided into 4 groups, with 10 plates per group. In Group 1, participants did not wear a face mask. In Group 2, participants wore a standard surgical mask. In Group 3, no mask was worn, but plates were pretreated with 5% povidone-iodine. In Group 4, no mask was worn, and participants remained silent for 30 seconds. The plates were then incubated at 37°C for 24 hours, and the number of colony-forming units (CFUs) was determined.

RESULTS

Mean bacterial growth were as follows: Group 1, 8.6 CFUs per subject; Group 2, 1.1 CFUs per subject; Group 3, 0.1 CFUs per subject; and Group 4, 2.4 CFUs per subject. Differences between the groups were statistically significant (P < 0.05), with the exception of Group 2 versus Group 4 (P = 0.115).

CONCLUSION

The use of a face mask and avoidance of talking each significantly decreased the dispersion of bacteria. Even without these interventions, plates pretreated with povidone-iodine demonstrated the least bacterial growth.

Intravitreal injection technique

As the intravitreal injection of therapeutic medication plays an increasingly large role in ophthalmology, its implementation continues to be modified and refined. Variations in injection technique are discussed, and the authors combine their clinical and research experience with a review of the literature to propose a recommended intravitreal injection protocol.

Abiotrophia defectiva: A rare cause of infective endocarditis

A case of Abiotrophia defectiva-caused infective endocarditis is described. The patient was successfully treated with penicillin combined with gentamicin. Due to the fastidious nature of the agent, there is a need for special media for isolation and moreover, there is a need for a future development of susceptibility assays applicable to the organism.

Polymerase chain reaction identification in aqueous humor of patients with postoperative endophthalmitis

PURPOSE

To identify bacterial agents in the aqueous humor of patients with postoperative endophthalmitis using eubacterial polymerase chain reaction (PCR) and conventional culture.

SETTING

University Hospital of Lyon E. Herriot, Lyon, France.

METHODS

Broad-range eubacterial PCR amplification followed by direct sequencing was used to identify microbial pathogens in ocular samples from 30 patients with acute or delayed-onset endophthalmitis, mainly after cataract surgery. Ocular samples included aqueous humor collected before the first intravitreal injection of antibiotics and vitreous samples collected at the time of the therapeutic pars plana vitrectomy.

RESULTS

Cultures were positive in 32% of cases and PCR in 61% of cases with aqueous humor samples. When associated, culture and PCR of aqueous humor samples allowed for a microbiological diagnosis in 71% of cases. Microorganisms cultured by conventional techniques matched those identified by PCR. When applied on vitreous pretreated with intravitreal antibiotics, PCR increased the identification rate from 18% to 62%.

CONCLUSIONS

Polymerase chain reaction assay of initial aqueous humor samples contributed to the diagnosis of endophthalmitis in 30% of cases. Previous use of intravitreal antibiotics did not seem to affect the ability to PCR-amplify DNA in the short term. Polymerase chain reaction-based technology was a useful adjunct to conventional culture because when used with aqueous humor samples only, the association of both techniques allowed for a microbiological diagnosis in 71% of cases of postoperative acute and delayed-onset endophthalmitis.

The diagnostic yield of vitrectomy specimen analysis in chronic idiopathic endogenous uveitis

PURPOSE

The low diagnostic yield of vitrectomy specimen analysis in chronic idiopathic uveitis (CIU) has been related to the complex nature of the underlying disease and to methodologic and tissue immanent factors in older studies. In an attempt to evaluate the impact of recently acquired analytic methods, the authors assessed the current diagnostic yield in CIU.

METHODS

Retrospective analysis of consecutive vitrectomy specimens from patients with chronic endogenous uveitis (n = 56) in whom extensive systemic workup had not revealed a specific diagnosis (idiopathic) and medical treatment had not resulted in a satisfying clinical situation. Patients with acute postoperative endophthalmitis served a basis for methodologic comparison (Group 2; n = 21).

RESULTS

In CIU, a specific diagnosis provided in 17.9% and a specific diagnosis excluded in 21.4%. In 60.7% the laboratory investigations were inconclusive. In postoperative endophthalmitis, microbiological culture established the infectious agent in 47.6%. In six of eight randomly selected cases, eubacterial PCR identified bacterial DNA confirming the culture results in three, remaining negative in two with a positive culture and being positive in three no growth specimens. A double negative result never occurred, suggesting a very high detection rate, when both tests were applied.

CONCLUSIONS

The diagnostic yield of vitrectomy specimen analysis has not been improved by currently routinely applied methods in recent years in contrast to the significantly improved sensitivity of combined standardized culture and PCR analysis in endophthalmitis. Consequently, the low diagnostic yield in CIU has to be attributed to insufficient understanding of the underlying pathophysiologic mechanisms.

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.

16S rDNA PCR analysis of infectious keratitis: a case series

PURPOSE

To discuss the value of polymerase chain reaction (PCR) in the management of bacterial infectious keratitis.

METHODS

Corneal scrapings of four patients with severe infectious keratitis were analysed by culture and PCR of 16S ribosomal DNA (rDNA), followed by direct sequencing of the resulting amplicon. The medical history of the patients included laser-assisted in-situ keratomileusis (LASIK), penetrating keratoplasty (PKP) and trauma.

RESULTS

Using PCR we were able to identify a possible pathogen in all four cases, while bacterial cultures were either negative or did not correspond to the clinical picture. The identified bacteria were a Pseudomonas species, Abiotrophia defectiva, Stenotrophomonas maltophilia and Porphyromonas gingivalis.

CONCLUSIONS

Analysis of corneal scrapings by 16S rDNA PCR should be considered as a supplement to standard microbiological procedures. However, the results of this relatively new method have to be interpreted carefully.

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.

Granulicatella and Abiotrophia species from human clinical specimens

One hundred one isolates of nutritionally variant streptococci from 97 patients were phenotypically characterized and compared with the type strains of Granulicatella adiacens (formerly Abiotrophia adiacens) (ATCC 49175(T)) Abiotrophia defectiva (ATCC 49176(T)), and Granulicatella elegans (formerly Abiotrophia elegans) (DSM 11693(T)). Of the isolates, 55 and 43 resembled G. adiacens and A. defectiva, respectively, while 3 strains resembled G. elegans. Phenotypic characteristics useful in differentiating between species within the genera Granulicatella and Abiotrophia (G. adiacens, G. elegans, Granulicatella balaenopterae, and A. defectiva) were production of alpha- and beta-galactosidase; production of beta-glucuronidase; hippurate hydrolysis; arginine dihydrolase activity; and acid production from trehalose, sucrose, pullulan, and tagatose. From the reports submitted with the specimens, the clinical diagnosis was endocarditis in 58% of patients and septicemia or bacteremia in 26% of patients.

Granulicatella and Abiotrophia species from human clinical specimens

One hundred one isolates of nutritionally variant streptococci from 97 patients were phenotypically characterized and compared with the type strains of Granulicatella adiacens (formerly Abiotrophia adiacens) (ATCC 49175(T)) Abiotrophia defectiva (ATCC 49176(T)), and Granulicatella elegans (formerly Abiotrophia elegans) (DSM 11693(T)). Of the isolates, 55 and 43 resembled G. adiacens and A. defectiva, respectively, while 3 strains resembled G. elegans. Phenotypic characteristics useful in differentiating between species within the genera Granulicatella and Abiotrophia (G. adiacens, G. elegans, Granulicatella balaenopterae, and A. defectiva) were production of alpha- and beta-galactosidase; production of beta-glucuronidase; hippurate hydrolysis; arginine dihydrolase activity; and acid production from trehalose, sucrose, pullulan, and tagatose. From the reports submitted with the specimens, the clinical diagnosis was endocarditis in 58% of patients and septicemia or bacteremia in 26% of patients.

Infiltrative keratitis associated with extended wear of hydrogel lenses and Abiotrophia defectiva

PURPOSE

Infiltrative keratitis is a common complication associated with extended wear of hydrogel lenses. Causative bacteria are often isolated from the lens at the time of an event. We report a case where three repeated occurrences of infiltrative keratitis were associated with contamination of the contact lenses by Abiotrophia defectiva.

METHODS

A 34-year-old man participating in a clinical trial of extended wear hydrogel contact lenses experienced three episodes of infiltrative keratitis. The clinical presentation was observed using a biomicroscope. At the time of each event, the contact lenses were removed aseptically and ocular swabs were taken for bacterial identification and enumeration. The condition was monitored until full resolution.

RESULTS

The condition was characterized by irritation, marked bulbar and limbal injection, and multiple focal subepithelial infiltrates. Many of the infiltrates also showed overlying staining with fluorescein. In each of the three events of infiltrative keratitis, A. defectiva was cultured from the contact lens and ocular swabs.

CONCLUSION

This is the first reported occurrence of infiltrative keratitis associated with A. defectiva contamination of contact lenses.

Characterization of the Tn916-like transposon Tn3872 in a strain of abiotrophia defectiva (Streptococcus defectivus) causing sequential episodes of endocarditis in a child

Clinical blood isolates from three sequential episodes of endocarditis occurring over a 6-month period in a child with a malformative cardiopathy were investigated. All isolates identified as Abiotrophia defectiva were resistant to erythromycin-clindamycin and to tetracycline-minocycline, due to the presence of sequences homologous to the erythromycin resistance gene ermB and to the tetracycline resistance gene tet(M), respectively. These resistance genes were located on a chromosomally borne composite Tn916-related transposon. These results demonstrate the involvement of conjugative transposons in the dissemination of antibiotic resistance in the genus Abiotrophia.