An epidemic of chronic pseudophakic endophthalmitis due to Ochrobactrum anthropi: clinical findings and managements of nine consecutive cases

Ochrobactrum anthropi infection following corneal transplantation -a case report and review of literature

BACKGROUND

Ochrobactrum anthropi is widely distributed and primarily infects patients with compromised immune functions . Historically, O. anthropi has been considered to possess low toxicity and pathogenicity; however, recent studies suggest that it may in fact cause severe purulent infections. In this case study, we examine a case of O. anthropi infection following corneal transplantation, exploring the occurrence and outcomes of such post-operative infections.

CASE PRESENTATION

A retrospective analysis of cases involved examinations, genetic testing for diagnosis, and subsequent treatment. In patients undergoing partial penetrating keratoplasty with a fungal corneal ulcer perforation, anterior chamber exudation and purulence were observed post-surgery. Despite antifungal treatment, genetic testing of the anterior chamber fluid and purulent material confirmed O. anthropi infection. The use of antimicrobial treatment specifically targeting O. anthropi was found to be effective in treating the infection.

CONCLUSION

Inflammatory reactions following corneal transplantation should be should be monitored for the presence of other infections. Genetic testing has significant implications for clinical diagnosis and treatment.

Ochrobactrum anthropi: A Rare Cause of Culture-Proven Acute Post-Operative Cluster Endophthalmitis

AIM

To report the clinical presentation and management outcomes of an outbreak of culture-proven post-operative endophthalmitis (POE) secondary to Ochrobactrum anthropi.

METHODS

This study was conducted at a tertiary-care eye hospital in South India.

RESULTS

Fifty-five patients underwent cataract surgery by six surgeons on three consecutive days in the same surgical facility in September 2020. Four patients developed POE after a mean interval of 12.0 ± 4.8 days and underwent immediate vitreous tap and intravitreal antibiotic injections (Vancomycin and Ceftazidime). All patients required a core vitrectomy (culture positive, n = 4/4). Two patients underwent an additional intraocular lens explantation, 2 and 4 months after presentation. All the four patients showed good anatomical and functional recoveries (mean follow-up, 5.75 ± 1.5 months). Two other patients had an exaggerated post-operative inflammation, which was successfully treated with topical medications.

CONCLUSIONS

O. anthropi is a rare cause of acute POE. Although the isolated organism was multi-drug resistant, the outcome was good in all the patients.

Clinical features of endophthalmitis clusters after cataract surgery and practical recommendations to mitigate risk: systematic review

Intraocular transmission of exogenous pathogens in cataract surgery can lead to endophthalmitis. This review evaluates the features of endophthalmitis clusters secondary to pathogen transmission in cataract surgery. Articles reporting on pathogen transmission in cataract surgery were identified via searches of Ovid MEDLINE, EMBASE, and Cochrane CENTRAL, and a total of 268 eyes from 24 studies were included. The most common source of infectious transmission was attributed to a contaminated intraocular solution (ie, irrigation solution, viscoelastic, or diluted antibiotic; n = 10). Visual acuity at presentation with infectious features was 1.89 logMAR (range: 1.35 to 2.58; ∼counting fingers) and 1.33 logMAR (range: 0.04 to 3.00; Snellen: ∼20/430) at last follow-up. Patients with diabetes had worse outcomes compared with patients without diabetes. The most frequently isolated pathogen from the infectious sources was Pseudomonas sp. (50.0%). This review highlights the various routes of pathogen transmission during cataract surgery and summarizes recommendations for the detection, prevention, and management of endophthalmitis clusters.

Genomics of Ochrobactrum pseudogrignonense (newly named Brucella pseudogrignonensis) reveals a new bla OXA subgroup

Ochrobactrum pseudogrignonense (newly named Brucella pseudogrignonensis) is an emerging pathogen in immunodeficient and immunocompetent patients. Most documented cases associated with Ochrobactrum are frequently catheter-related and exhibit wide-spectrum β-lactam resistance. Misidentification of this pathogen using commercial bacterial identification kits is common. We identified a case of O. pseudogrignonense infection associated with cholelithiasis. The O. pseudogrignonense genome was sequenced and reconstructed using a Nanopore and Illumina hybrid strategy. A novel bla _OXA-919 divergent from existing OXA members was identified and subsequent analysis revealed its existence in all available O. pseudogrignonense genomes, which forms a new phylogenetic subgroup distinct from other OXA clusters. Further analysis demonstrated the presence of the novel bla _OXA-919 in the chromosome of several other Ochrobactrum species. Our study indicated that Ochrobactrum chromosomes may be a reservoir of bla _OXA-919 β-lactamases.

The Genus Ochrobactrum as Major Opportunistic Pathogens

Ochrobactrum species are non-enteric, Gram-negative organisms that are closely related to the genus Brucella. Since the designation of the genus in 1988, several distinct species have now been characterised and implicated as opportunistic pathogens in multiple outbreaks. Here, we examine the genus, its members, diagnostic tools used for identification, data from recent Ochrobactrum whole genome sequencing and the pathogenicity associated with reported Ochrobactrum infections. This review identified 128 instances of Ochrobactrum spp. infections that have been discussed in the literature. These findings indicate that infection review programs should consider investigation of possible Ochrobactrum spp. outbreaks if these bacteria are clinically isolated in more than one patient and that Ochrobactrum spp. are more important pathogens than previously thought.

Management and Microbiological Characteristics of Membrane Formation on a Hydrophilic Acrylic Intraocular Lens: A Clinical Case Series and Material Comparative Study of Different IOLs

Background/Aims. To report a case series of membrane formation on intraocular lenses (IOLs) after uneventful phacoemulsification and to evaluate the material characteristics and biofilm formation on different IOLs. Methods. Ten eyes implanted with the same type of IOLs were found to have membranes on their IOLs after uneventful phacoemulsification from May 2015 to May 2016. No other patients were found with the same phenomenon among 11236 patients who underwent cataract surgeries during this period. To further investigate the reasons for their formation, we assessed seven types of IOLs used in our hospital, including their material characteristics and the presence of microbes (Staphylococcus epidermidis) on the IOL surface by scanning electron microscopy (SEM). All IOLs were incubated under in vitro flow conditions (BioFlux 1000Z). After 36 h, the IOLs were taken from the system, and both the bound bacteria and biofilm formation were observed. Results. Five eyes underwent intravitreal injections of ceftazidime and norvancomycin with one positive culture obtained from the anterior chamber fluid. The other five eyes only received topical treatment of gatifloxacin/levofloxacin and tobramycin. At the last follow-up, all patients had best-corrected visual acuity (BCVA) of 20/50 or better. In the biofilm study on the IOL surface, Staphylococcus epidermidis biofilms formed more readily on hydrophilic acrylic IOLs than on hydrophobic acrylic IOLs. Conclusions. Bacterial adhesion and biofilm tend to develop on certain types of IOLs because of the characteristics of the biomaterial.

Ochrobactrum anthropi Keratitis with Focal Descemet's Membrane Detachment and Intracorneal Hypopyon

Purpose. To describe a unique case of O. anthropi keratitis associated with a rare manifestation of Descemet's membrane detachment and intracorneal hypopyon and to discuss challenges in diagnosis and management. Methods. Best-corrected visual acuity was measured with Snellen letters. Corneal scrapings were performed and aerobic, viral, herpetic, acid-fast bacilli, Acanthamoeba, and fungal stains and cultures were obtained. Following evisceration, tissue was evaluated for histologic features and again stained for bacteria, mycobacteria, Acanthamoeba, fungi, and viral particles. Results. Initial presentation to our institute was notable for a corneal ulcer, focal Descemet's membrane detachment, and intracorneal hypopyon. Speciation of initial corneal scrapes revealed Ochrobactrum anthropi and initial management included fortified tobramycin. Despite medical therapy, the patient developed a corneal perforation and required subsequent evisceration. Conclusion. O. anthropi is an emerging ocular pathogen that has not been previously reported in cases of keratitis. As this pathogen becomes increasingly recognized as a source of ocular infections, it is important to identify and treat aggressively to avoid vision-threatening disease.

Chronic postoperative endophthalmitis after cataract surgery secondary to vancomycin-resistant Ochrobactrum anthropi: case report and literature review

Background

The aim of this study was to report an unusual case of chronic postoperative endophthalmitis following cataract surgery, secondary to Ochrobactrum anthropi that was found to be resistant to vancomycin.

Findings

Anterior chamber paracentesis cultures grew gram negative bacilli Ochrobactrum anthropi. The patient was treated with a series of intracameral injections of moxifloxacin, with adjuvant oral moxifloxacin. Posterior sub-Tenon and oral corticosteroids were used to treat cystoid macular edema. Explantation of the intraocular lens (IOL)-capsular bag complex was avoided.

Conclusions

Chronic postoperative endophthalmitis is a rare entity, often due to indolent pathogens that sequester in the capsular bag. Aggressive surgical intervention may be avoided with the use of adequate intraocular antibiotic, provided that the offending organism demonstrates appropriate antibiotic susceptibilities.

Typing of Ochrobactrum anthropi clinical isolates using automated repetitive extragenic palindromic-polymerase chain reaction DNA fingerprinting and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry

BACKGROUND

Ochrobactrum anthropi (O. anthropi), is a non-fermenting gram-negative bacillus usually found in the environment. Nevertheless, during the past decade it has been identified as pathogenic to immunocompromised patients. In this study, we assessed the usefulness of the automated repetitive extragenic palindromic-polymerase chain reaction (rep-PCR-based DiversiLab™ system, bioMèrieux, France) and of matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF MS) for typing of twentythree O. anthropi clinical isolates that we found over a four-months period (from April 2011 to August 2011) in bacteriemic patients admitted in the same operative unit of our hospital. Pulsed-field gel electrophoresis (PFGE), commonly accepted as the gold standard technique for typing, was also used. Analysis was carried out using the Pearson correlation coefficient to determine the distance matrice and the unweighted pair group method with arithmetic mean (UPGMA) to generate dendogram.

RESULTS

Rep-PCR analysis identified four different patterns: three that clustered together with 97% or more pattern similarity, and one whose members showed < 95% pattern similarity. Interestingly, strains isolated later (from 11/06/2011 to 24/08/2011) displayed a pattern with 99% similarity. MALDI-TOF MS evaluation clustered the twentythree strains of O. anthropi into a single group containing four distinct subgroups, each comprising the majority of strains clustering below 5 distance levels, indicating a high similarity between the isolates.

CONCLUSIONS

Our results indicate that these isolates are clonally-related and the methods used afforded a valuable contribution to the epidemiology, prevention and control of the infections caused by this pathogen.

Intravitreal moxifloxacin in the management of Ochrobactrum intermedium endophthalmitis due to metallic intraocular foreign body

A healthy 34-year-old man presented with Ochrobactrum intermedium endophthalmitis due to a metallic intraocular foreign body. After vitrectomy, lensectomy, removal of the metallic intraocular foreign body, intravitreal vancomycin and ceftazidime, and systemic ciprofloxacin, intraocular inflammation worsened. Repeat vitreous culture confirmed persistent endophthalmitis due to multidrug-resistant O. intermedium. The endophthalmitis successfully resolved after the administration of intravitreal moxifloxacin.

Anterior vitrectomy and partial capsulectomy via anterior approach to treat chronic postoperative endophthalmitis

AIM

To describe the results of vitrectomy and partial capsulectomy via anterior approach surgical technique in treatment of chronic postoperative endophthalmitis (CPE).

METHODS

Clinical records of 9 patients treated for CPE between 2006 and 2010 were reviewed retrospectively. All of these patients were treated with vitrectomy and partial capsulectomy via anterior approach.

RESULTS

Six of 9 patients were male. The average patients' age was (60±8.1) years. The average period between cataract extraction and onset of signs and symptoms was (3.6±1.3) weeks. The average presenting visual acuity was 0.3±0.1 and the average final post operative visual acuity was 0.7±0.2. The mean follow-up period was (28.1±8.9) weeks. In all patients, the inflammation subsided after surgery.

CONCLUSION

Our results suggest that anterior vitrectomy and partial capsulectomy via anterior approach may be considered as potentially useful and relatively less invasive technique to treat CPE.

Outbreak of Ochrobactrum anthropi endophthalmitis following cataract surgery

Postoperative endophthalmitis often progresses to significant visual impairment. This paper describes an outbreak of Ochrobactrum anthropi endophthalmitis following cataract surgery, and propose a new sterilization protocol to minimize the risk of further cases. Medical records of patients with O. anthropi endophthalmitis or with suggestive clinical findings during the outbreak were reviewed. Seven cases of O. anthropi pseudophakic endophthalmitis were confirmed between 24 July and 10 November 2010. The most probable cause of the outbreak of Ochrobactrum anthropi endophthalmitis was contamination of the tubing of the phaco-emulsification machine. Following introduction of a new sterilization protocol, no further cases occurred in over 1000 subsequent procedures.

Ochrobactrum anthropi: a rare cause of pneumonia

Ochrobactrum anthropi, a Gram-negative bacillus, is an unusual human pathogen. It has been implicated primarily in catheter-related bloodstream infections. Sporadic cases of infection at other body sites have been reported. Pneumonia, however, is an exceedingly rare clinical manifestation; only one case has been reported in the medical literature so far. We present another case of lower respiratory tract infection secondary to O. anthropi in a patient who was critically ill, but recovered with a favorable outcome. We have provided an overview of clinical manifestations, diagnosis, and treatment of infections due to this rare microorganism.

Acute Postoperative Endophthalmitis Following Cataract Surgery: A Review

Endophthalmitis following cataract surgery is rare but continues to be a serious complication following cataract surgery. Over the years, the incidence of endophthalmitis has declined because of various preoperative and perioperative measures. They include use of antiseptic and appropriate surgical draping techniques. In this review, we have focused on the incidence, existing risk factors, various clinical features, management strategies, and prophylaxis pertaining to postoperative endophthalmitis following cataract surgery. Outcomes and pitfalls of 2 landmark studies, namely, the Endophthalmitis Vitrectomy Study and the European Society of Cataract and Refractive Surgeons Endophthalmitis Study, are briefly mentioned.Infectious endophthalmitis following cataract surgery is a dreaded complication. Preoperative identification of risk factors and effective prophylaxis could help in reducing its incidence. Early diagnosis followed by management of these patients either with vitreous tap or vitrectomy coupled with intravitreal antibiotics holds the key.

Multilocus sequence typing supports the hypothesis that Ochrobactrum anthropi displays a human-associated subpopulation

Background

Ochrobactrum anthropi is a versatile bacterial species with strains living in very diverse habitats. It is increasingly recognized as opportunistic pathogen in hospitalized patients. The population biology of the species particularly with regard to the characteristics of the human isolates is being investigated. To address this issue, we proposed a polyphasic approach consisting in Multi-Locus Sequence Typing (MLST), multi-locus phylogeny, genomic-based fingerprinting by pulsed-field gel electrophoresis (PFGE) and antibiotyping.

Results

We tested a population of 70 O. anthropi clinical (n = 43) and environmental (n = 24) isolates as well as the type strain O. anthropi ATCC49188^T and 2 strains of Ochrobactrum lupini and Ochrobactrum cytisi isolated from plant nodules. A Multi-Locus Sequence Typing (MLST) scheme for O. anthropi is proposed here for the first time. It was based on 7 genes (3490 nucleotides) evolving mostly by neutral mutations. The MLST approach suggested an epidemic population structure. A major clonal complex corresponded to a human-associated lineage since it exclusively contained clinical isolates. Genomic fingerprinting separated isolates displaying the same sequence type but it did not detect a population structure that could be related to the origin of the strains. None of the molecular method allowed the definition of particular lineages associated to the host-bacteria relationship (carriage, colonisation or infection). Antibiotyping was the least discriminative method.

Conclusion

The results reveal a human-associated subpopulation in our collection of strains. The emergence of this clonal complex was probably not driven by the antibiotic selective pressure. Therefore, we hypothesise that the versatile species O. anthropi could be considered as a human-specialized opportunistic pathogen.

Chronic postoperative Roseomonas endophthalmitis

We report one case with chronic postoperative endophthalmitis caused by Roseomonas species. Roseomonas spp. induced chronic endophthalmitis, which might result in misdiagnosis and delayed treatment and causes ocular damage and severe visual loss. This report is the first one related to a case with postoperative endophthalmitis secondary to Roseomonas infection.

The genome of Rhodobacter sphaeroides strain 2.4.1 encodes functional cobinamide salvaging systems of archaeal and bacterial origins

Bacteria and archaea use distinct pathways for salvaging exogenous cobinamide (Cbi), a precursor of adenosylcobalamin (coenzyme B(12)). The bacterial pathway depends on a bifunctional enzyme with kinase and guanylyltransferase activities (CobP in aerobic adenosylcobalamin synthesizers) to convert adenosylcobinamide (AdoCbi) to AdoCbi-guanosine diphosphate (AdoCbi-GDP) via an AdoCbi-phosphate intermediate. Archaea lack CobP, and use a different strategy for the synthesis of AdoCbi-GDP. Archaea cleave off the aminopropanol group of AdoCbi using the CbiZ AdoCbi amidohydrolase to generate adenosylcobyric acid, which is converted to AdoCbi-phosphate by the CbiB synthetase, and to AdoCbi-GDP by the CobY guanylyltransferase. We report phylogenetic, in vivo and in vitro evidence that the genome of Rhodobacter sphaeroides encodes functional enzymes for Cbi salvaging systems of both bacterial and archaeal origins. Products of the reactions were identified by high-performance liquid chromatography, UV-visible spectroscopy and bioassay. The cbiZ genes of several bacteria and archaea restored Cbi salvaging in a strain of Salmonella enterica unable to salvage Cbi. Phylogenetic data led us to conclude that CbiZ is an enzyme of archaeal origin that was horizontally transferred to bacteria. Reasons why some bacteria may contain both types of Cbi salvaging systems are discussed.