Clinical, microbiological profile and treatment outcome of ocular infections caused by Achromobacter xylosoxidans

A Rare Case of Acute Post-cataract Surgery Endophthalmitis Associated With Achromobacter xylosoxidans

Achromobacter xylosoxidans is rarely reported as a causative agent of post-cataract surgery endophthalmitis. Here, we present a case where timely surgical intervention preserved the patient's vision. A 68-year-old man presented with clinical signs of endophthalmitis in his right eye three days after uneventful cataract surgery. He was initially treated with intravitreal, topical, and systemic antibiotics. After starting intravitreal, topical, and systemic antibiotics, his condition deteriorated on the second day of treatment. A prompt pars plana vitrectomy (PPV) with the removal of the posterior chamber intraocular lens (PCIOL) was performed. Culture from the intravitreal tapping yielded A. xylosoxidans, which was sensitive to ceftazidime and piperacillin. His condition was better post-PPV, and the infection was under control until day 10 post-first PPV. There was a recrudescence of infection with a recurrence of hypopyon and loculations detected on B-scan ultrasound. A second PPV with the complete removal of the lens capsule was performed. One month later, his right eye was quiet without inflammation, with a best-corrected vision of 20/30. A. xylosoxidans is a rare but serious pathogen of endophthalmitis that often necessitates multiple surgical interventions. Although it may not initially respond to intravitreal injections and vitrectomy, appropriate treatment, such as the removal of the intraocular lens and capsulectomy, can still result in favorable visual outcomes.

Achromobacter xylosoxidans keratitis in a LASIK flap treated with intrastromal antibiotics: a case report

Intrastromal antibiotic injections are a type of treatment that can be very useful in bacterial keratitis refractory to topical antibiotics. We present the case of a 44-year-old woman with an infiltrate in a laser in situ keratomiuleusis (LASIK) flap and growth of Achromobacter xylosoxidans, who was treated with topical ceftazidime for 1 month. However, after discontinuation of the antibiotic, there was a worsening with growth of the same germ. Topical treatment was reintroduced and, due to suspicion of germ reservoir, it was decided to give three cycles of intrastromal ceftazidime injections, the last one also with moxifloxacin, with good results. After 4 months asymptomatic and without treatment at the moment, no signs of recurrence have been observed. This case supports the usefulness of intraestromal injections in refractory cases to the topical medication.

Ocular Bacterial Infections: A Ten-Year Survey and Review of Causative Organisms Based on the Oklahoma Experience

Ocular infections can be medical emergencies that result in permanent visual impairment or blindness and loss of quality of life. Bacteria are a major cause of ocular infections. Effective treatment of ocular infections requires knowledge of which bacteria are the likely cause of the infection. This survey of ocular bacterial isolates and review of ocular pathogens is based on a survey of a collection of isolates banked over a ten-year span at the Dean McGee Eye Institute in Oklahoma. These findings illustrate the diversity of bacteria isolated from the eye, ranging from common species to rare and unique species. At all sampled sites, staphylococci were the predominant bacteria isolated. Pseudomonads were the most common Gram-negative bacterial isolate, except in vitreous, where Serratia was the most common Gram-negative bacterial isolate. Here, we discuss the range of ocular infections that these species have been documented to cause and treatment options for these infections. Although a highly diverse spectrum of species has been isolated from the eye, the majority of infections are caused by Gram-positive species, and in most infections, empiric treatments are effective.

Atypical microbial keratitis

Atypical microbial keratitis refers to corneal infections caused by micro-organisms not commonly encountered in clinical practice. Unlike infections caused by common bacteria, cases of atypical microbial keratitis are often associated with worse clinical outcomes and visual prognosis. This is due to the challenges in the identification of causative organisms with standard diagnostic techniques, resulting in delays in the initiation of appropriate therapies. Furthermore, due to the comparatively lower incidence of atypical microbial keratitis, there is limited literature on effective management strategies for some of these difficult to manage corneal infections. This review highlights the current management and available evidence of atypical microbial keratitis, focusing on atypical mycobacteria keratitis, nocardia keratitis, achromobacter keratitis, and pythium keratitis. It will also describe the management of two uncommonly encountered conditions, infectious crystalline keratopathy and post-refractive infectious keratitis. This review can be used as a guide for clinicians managing patients with such challenging corneal infections.

Delayed-onset endophthalmitis associated with Achromobacter species developed in acute form several months after cataract surgery: Three case reports

BACKGROUND

Achromobacter species-associated endophthalmitis is rare and may present as either acute or chronic postoperative endophthalmitis. Delayed-onset Achromobacter species endophthalmitis appearing in acute presentation that develops more than several months after cataract surgery is very rare. Intraocular lens (IOL) removal is commonly recommended to treat Achromobacter species endophthalmitis, which is based on previous studies. Here, we report the results of surgery without IOL removal when treating patients with delayed-onset postoperative Achromobacter species endophthalmitis that developed in an acute form.

CASE SUMMARY

Three patients visited our ophthalmology clinic due to visual impairment that began 2-3 d earlier. They had undergone cataract surgery 5-18 mo prior. Best-corrected visual acuity of the diseased eye was between counting fingers at 30 cm to non-light perception. They showed conjunctival injection, inflammation in the anterior chamber (cell reaction 4+) and hypopyon formation. The patients were diagnosed with infectious endophthalmitis and immediately underwent pars plana vitrectomy, anterior chamber irrigation and intravitreal injection of ceftazidime and vancomycin. Before fluid infusion, a vitreous specimen was obtained. In all cases, the IOLs were not removed. Achromobacter species was detected on vitreous specimen culture. After surgery, the vitreous opacity decreased gradually and there was little retinal damage. At 1 mo after treatment, the best-corrected visual acuity had improved to 20/50 and 20/40.

CONCLUSION

Delayed onset postoperative endophthalmitis caused by Achromobacter species can appear in an acute form. All patients responded well to early vitrectomy and administration of empirical antibiotics including ceftazidime. There was no need for IOL removal during surgery.

A Cluster of Corneal Donor Rim Cultures Positive for Achromobacter Species Associated With Contaminated Eye Solution

PURPOSE

To investigate a cluster of corneoscleral rim cultures positive for Achromobacter species over a 6-month period at Massachusetts Eye and Ear.

METHODS

An increased rate of positive corneal donor rim cultures was noted at Massachusetts Eye and Ear between July and December 2017. Positive cultures were subjected to identification and antimicrobial susceptibility testing by phenotypic (MicroScan WalkAway) and genotypic (16S rDNA sequencing) methods. Samples of the eye wash solution (GeriCare) used in the eye bank were also evaluated. Antimicrobial activity of Optical-GS against Achromobacter spp. at 4°C and 37°C was assessed by time-kill kinetics assay.

RESULTS

Of 99 donor rims cultured, 14 (14.1%) grew bacteria with 11 (78.6%) due to uncommon nonfermenting Gram-negative bacilli. These had been identified by standard automated methods as Achromobacter (n = 3), Alcaligenes (n = 3), Ralstonia (n = 2), Pseudomonas (n = 2), and Stenotrophomonas (n = 1). Eight of these 11 isolates were subsequently available for molecular identification, and all were identified as Achromobacter spp. Six bottles of eyewash solution were evaluated and were positive for abundant Achromobacter spp. (3.4 × 105 ± 1.1 CFU/mL). Optisol-GS had no bactericidal activity against Achromobacter spp. at 4°C after 24-hour incubation but was bactericidal at 37°C. None of the patients who had received the contaminated corneas developed postoperative infection.

CONCLUSIONS

An eyewash solution arising from a single lot was implicated in the contamination of donor rims by Achromobacter spp. The isolates were able to survive in the Optisol-GS medium at the recommended storage temperature. This highlights the need to continue improving protocols for tissue preparation and storage.

Chronic Conjunctivitis From a Retained Contact Lens

PURPOSE

To help clinicians diagnose and manage unilateral recalcitrant chronic bacterial conjunctivitis secondary to a retained soft contact lens and describe the first report of Gram-negative bacteria causing this condition.

METHODS

Chart review of successive cases presenting with unilateral chronic conjunctivitis with positive cultures and a retained contact lens.

RESULTS

Three cases were identified and described. Culturing of the retained contact lenses grew Pseudomonas aeruginosa in the first case, Achromobacter xylosoxidans in the second, and Staphylococcus epidermidis in the third. All three patients were successfully treated with removal of the retained lens and targeted antibiotic eyedrop therapy.

CONCLUSIONS

Unilateral chronic recurrent or recalcitrant purulent papillary conjunctivitis is rare, and a retained contact lens should be suspected in patients with a history of wearing contact lenses. Careful examination with double eversion of the upper eyelid and sweeping of the fornices can recover the offending lens. Although only Gram-positive organisms have been isolated in previous reports, two of our three cultures grew Gram-negative organisms, highlighting the importance of broad-spectrum antibiotic usage for these cases.

Adhesion of Pseudomonas aeruginosa, Achromobacter xylosoxidans, Delftia acidovorans, Stenotrophomonas maltophilia to contact lenses under the influence of an artificial tear solution

Corneal infection is a devastating sight-threatening complication that is associated with contact lens (CL) wear, commonly caused by Pseudomonas aeruginosa. Lately, Achromobacter xylosoxidans, Delftia acidovorans, and Stenotrophomonas maltophilia have been associated with corneal infection. This study investigated the adhesion of these emerging pathogens to CLs, under the influence of an artificial tear solution (ATS) containing a variety of components commonly found in human tears. Two different CL materials, etafilcon A and senofilcon A, either soaked in an ATS or phosphate buffered saline, were exposed to the bacteria. Bacterial adhesion was investigated using a radio-labeling technique (total counts) and plate count method (viable counts). The findings from this study revealed that in addition to P. aeruginosa, among the emerging pathogens evaluated, A. xylosoxidans showed an increased propensity for adherence to both CL materials and S. maltophilia showed lower viability. ATS influenced the viable counts more than the total counts on CLs.

Keratitis Due to Achromobacter xylosoxidans in a Contact Lens User

OBJECTIVES

Ocular infections due to Achromobacter xylosoxidans are extremely uncommon; their diagnosis is a challenge and the optimal treatment remains controversial. We present a case of A. xylosoxidans in a contact lens user and a review of the literature to facilitate diagnostic suspicion and empirical therapeutic management.

METHODS

Review of the literature in PubMed and MEDLINE. We also document a case diagnosed in our department in January 2016.

SETTING

Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain.

RESULTS

According to the literature, clinical manifestations and antibiotic sensitivity of A. xylosoxidans varied greatly. Our patient with no history of keratopathy presented three risk factors that made the diagnosis suspicious. The infection was resolved with topical moxifloxacin and fluorometholone.

CONCLUSIONS

A. xylosoxidans is an uncommon cause of infection, but must be suspected in atypical keratitis, reported contact with warm or still waters, use of contact lenses, or previous corneal damage. In these cases, microbiological studies and antibiotic sensitivity testing are particularly important.

The successful treatment of a multidrug-resistant Achromobacter xylosoxidans corneal ulcer with topical meropenem

Microbial keratitis is a common corneal condition, with many known risk factors. We present a case of an 88-year-old female patient with a multidrug-resistant Achromobacter xylosoxidans corneal ulcer in a previously failed second penetrating keratoplasty, successfully managed with topical meropenem drops administered hourly around the clock, for five days preceding and then hourly day only, for five days following a repeat third penetrating keratoplasty. Topical meropenem 50 mg/mL was prepared by mixing a 500 mg vial of meropenem with 10 mL of sterile water with pharmacy advice that administration should be within an hour. To the best of our knowledge, this is the first report of the use of topical meropenem in the management of A.xylosoxidans keratitis. This case highlights the importance of the mean inhibitory concentrations for antibiotics when considering sensitivities. Topical meropenem may be a useful treatment option for multidrug-resistant bacterial corneal ulcers that are resistant to conventional therapy.

Severe Achromobacter xylosoxidans keratitis with deep corneal involvement

Purpose

To describe a case of Achromobacter xylosoxidans keratitis with deep involvement of the corneal stroma and discuss its management.

Observations

A 73 year-old monocular male with infectious keratitis of the right eye was referred to the Wilmer Eye Institute after a month of empiric treatment with besifloxacin. On presentation, slit lamp examination of the right eye demonstrated a diffusely edematous cornea with three areas of corneal infiltrates and an overlying epithelial defect and a 1.3 mm hypopyon in the anterior chamber. The corneal culture performed grew A. xylosoxidans. Empiric antibiotic regimen was adjusted once corneal culture susceptibility results were available. Seven days later, slit lamp examination demonstrated a resolving epithelial defect, stable infiltrates, and resolution of the hypopyon. After approximately two months of follow up with his primary ophthalmologist, he was noted to have recurrent hypopyon and infiltrates and was referred back to Wilmer. Slit lamp examination again demonstrated an epithelial defect, diffuse corneal haze, deep stromal infiltrates, and a 1 mm hypopyon. Corneal infiltrates were too deep to culture. Ultimately, the patient underwent a therapeutic penetrating keratoplasty with anterior chamber washout resulting in improvement of vision.

Conclusions and importance

The indolent progression of A. xylosoxidans keratitis may predispose patients to delayed presentation and treatment. This can result in deep stromal infection that complicates management due to poor antibiotic penetration. Deep stromal infections in A. xylosoxidans keratitis warrant the consideration of intrastromal antibiotic injection or early therapeutic penetrating keratoplasty.

Comparative activity of antimicrobials against Pseudomonas aeruginosa, Achromobacter xylosoxidans and Stenotrophomonas maltophilia keratitis isolates

BACKGROUND/AIMS

Achromobacter xylosoxidans and Stenotrophomonas maltophilia are emerging corneal pathogens, which are closely related to Pseudomonas aeruginosa, and have intrinsic resistance to many commonly available antimicrobials. The purpose of this study is to compare the in vitro efficacy of 12 antimicrobial agents against A. xylosoxidans, S. maltophilia and P. aeruginosa isolates recovered from clinical cases of keratitis.

METHODS

Recovered corneal isolates (n=58) were identified and extracted from the Microbiology Data Bank of the Bascom Palmer Eye Institute. Comparative in vitro minimum inhibitory concentration (MIC) susceptibility profiles for fluoroquinolones, aminoglycosides, beta-lactams and miscellaneous antibiotics were recorded using the E-test methodology. Pharmacodynamic indices (Cmax/MIC) were calculated.

RESULTS

A. xylosoxidans and S. maltophilia isolates were resistant to fluoroquinolones, aminoglycosides and ceftazidime (susceptibility rate ranging from 0% to 30%) while P. aeruginosa isolates showed a susceptibility rate of 95%-100% to these antimicrobials (P<0.00001 for the various antimicrobials). Exception was moxifloxacin with 80% of susceptibility rate to S. maltophilia isolates and Cmax/MIC=10.19. Ninety to 100% susceptibility rates were found for minocycline and trimethoprim/sulfamethoxazole for both A. xylosoxidans and S. maltophilia. One hundred per cent of the A. xylosoxidans isolates were susceptible to piperacillin/tazobactam and ticarcillin/clavulanic acid.

CONCLUSIONS

There is a significant difference in susceptibility patterns between A. xylosoxidans, S. maltophilia and P. aeruginosa. Fluoroquinolones and aminoglycosides may not be effective against A. xylosoxidans and S. maltophilia. Antibiotics that are not commercially available as eye drops, such as beta-lactams for A. xylosoxidans, and trimethoprim/sulfamethoxazole and minocycline for both A. xylosoxidans and S. maltophilia should be considered.

Characterization and genome comparisons of three Achromobacter phages of the family Siphoviridae

In this study, we present the characterization and genomic data of three Achromobacter phages belonging to the family Siphoviridae. Phages 83-24, JWX and JWF were isolated from sewage samples in Paris and Braunschweig, respectively, and infect Achromobacter xylosoxidans, an emerging nosocomial pathogen in cystic fibrosis patients. Analysis of morphology and growth parameters revealed that phages 83-24 and JWX have similar properties, both have nearly the same head and tail measurements, and both have a burst size between 85 and 100 pfu/cell. In regard to morphological properties, JWF had a much longer and more flexible tail compared to other phages. The linear double-stranded DNAs of all three phages are terminally redundant and not circularly permutated. The complete nucleotide sequences consist of 81,541 bp for JWF, 49,714 bp for JWX and 48,216 bp for 83-24. Analysis of the genome sequences showed again that phages JWX and 83-24 are quite similar. Comparison to the GenBank database via BLASTN revealed partial similarities to Roseobacter phage RDJL phi1 and Burkholderia phage BcepGomr. In contrast, BLASTN analysis of the genome sequence of phage JWF revealed only few similarities to non-annotated prophage regions in different strains of Burkholderia and Mesorhizobium.

Clinical Features, Antibiotic Susceptibility Profiles, and Outcomes of Infectious Keratitis Caused by Achromobacter xylosoxidans

PURPOSE

Reports on Achromobacter xylosoxidans ocular infections are increasing, drawing attention to its emerging role in infectious keratitis. The purpose of this study is to report the clinical features, antibiotic sensitivities, and visual outcomes of infectious keratitis secondary to Achromobacter xylosoxidans.

METHODS

A microbiology database and clinical chart review was performed in all patients diagnosed with A. xylosoxidans keratitis at the Bascom Palmer Eye Institute between the years 1987 and 2014. Initial presentation, antimicrobial susceptibilities, minimum inhibitory concentrations (MICs), treatment course, and outcomes were recorded.

RESULTS

Twenty-eight patients were identified. The main risk factors were corneal graft (n = 8, 28.6%) and contact lens wear (n = 8, 28.6%). On presentation, visual acuity was 20/100 or worse in 20 (71.2%) patients. Hypopyon was present in 7 (25.0%) patients. In most cases, topical fluoroquinolones or tobramycin were the initial treatment, often accompanied by vancomycin. High susceptibility rates were found for piperacillin [100%, minimum inhibitory concentration for 90% of isolates (MIC90) = 8] and ticarcillin (100%, MIC90 = 16). Low susceptibility rates were documented for ciprofloxacin (46.7%, MIC90 = 8), tobramycin (26.7%, MIC90 = 16), and gentamicin (20%, MIC90 = 16). One (3.6%) patient suffered endophthalmitis. Six (21.4%) patients underwent therapeutic penetrating keratoplasty, and 2 (7.1%) patients had conjunctival flap surgery. Visual acuity at final follow-up was 20/100 or worse in 16 (57.1%) patients.

CONCLUSIONS

Infectious keratitis caused by A. xylosoxidans is associated with poor visual outcomes. Fluoroquinolones and aminoglycosides are not appropriate treatments for these ocular infections. Further studies are needed to define the clinical application of compound piperacillin and ticarcillin eye drops.

Achromobacter respiratory infections

Achromobacteria are ubiquitous environmental organisms that may also become opportunistic pathogens in certain conditions, such as cystic fibrosis, hematologic and solid organ malignancies, renal failure, and certain immune deficiencies. Some members of this genus, such as xylosoxidans, cause primarily nosocomially acquired infections affecting multiple organ systems, including the respiratory tract, urinary tract, and, less commonly, the cardiovascular and central nervous systems. Despite an increasing number of published case reports and literature reviews suggesting a global increase in achromobacterial disease, most clinicians remain uncertain of the organism's significance when clinically isolated. Moreover, effective treatment can be challenging due to the organism's inherent and acquired multidrug resistance patterns. We reviewed all published cases to date of non-cystic fibrosis achromobacterial lung infections to better understand the organism's pathogenic potential and drug susceptibilities. We found that the majority of these cases were community acquired, typically presenting as pneumonias (88%), and were most frequent in individuals with hematologic and solid organ malignancies. Our findings also suggest that achromobacterial lung infections are difficult to treat, but respond well to extended-spectrum penicillins and cephalosporins, such as ticarcillin, piperacillin, and cefoperazone.

Endophthalmitis caused by Achromobacter xylosoxidans after cataract surgery

PURPOSE

To report Achromobacter xylosoxidans as a cause of both acute-onset and delayed-onset postoperative endophthalmitis after cataract surgery.

METHODS

A noncomparative consecutive case series of patients with culture-proven A. xylosoxidans endophthalmitis between 1970 and 2012. Cataract surgery and intraocular lens placement were performed in all patients before endophthalmitis. Positive cultures were obtained from the vitreous, capsular bag, and/or the removed intraocular lens.

RESULTS

The clinical diagnosis was confirmed in four patients with positive cultures. Two patients with endophthalmitis had a preliminary culture report of Pseudomonas species. In addition to receiving intravitreal antibiotics, all patients underwent capsulectomy and intraocular lens removal at the time of pars plana vitrectomy. Visual acuity at last follow-up was 20/40 or better in 2 (50%) of the 4 patients, but the remaining 2 patients were 20/200 or worse.

CONCLUSION

A. xylosoxidans may be a cause of acute, recurrent, and delayed-onset postoperative endophthalmitis after cataract surgery. Complete capsulectomy and intraocular lens removal can be considered in recurrent and recalcitrant patients.

First genome sequences of Achromobacter phages reveal new members of the N4 family

BACKGROUND

Multi-resistant Achromobacter xylosoxidans has been recognized as an emerging pathogen causing nosocomially acquired infections during the last years. Phages as natural opponents could be an alternative to fight such infections. Bacteriophages against this opportunistic pathogen were isolated in a recent study. This study shows a molecular analysis of two podoviruses and reveals first insights into the genomic structure of Achromobacter phages so far.

METHODS

Growth curve experiments and adsorption kinetics were performed for both phages. Adsorption and propagation in cells were visualized by electron microscopy. Both phage genomes were sequenced with the PacBio RS II system based on single molecule, real-time (SMRT) technology and annotated with several bioinformatic tools. To further elucidate the evolutionary relationships between the phage genomes, a phylogenomic analysis was conducted using the genome Blast Distance Phylogeny approach (GBDP).

RESULTS

In this study, we present the first detailed analysis of genome sequences of two Achromobacter phages so far. Phages JWAlpha and JWDelta were isolated from two different waste water treatment plants in Germany. Both phages belong to the Podoviridae and contain linear, double-stranded DNA with a length of 72329 bp and 73659 bp, respectively. 92 and 89 putative open reading frames were identified for JWAlpha and JWDelta, respectively, by bioinformatic analysis with several tools. The genomes have nearly the same organization and could be divided into different clusters for transcription, replication, host interaction, head and tail structure and lysis. Detailed annotation via protein comparisons with BLASTP revealed strong similarities to N4-like phages.

CONCLUSIONS

Analysis of the genomes of Achromobacter phages JWAlpha and JWDelta and comparisons of different gene clusters with other phages revealed that they might be strongly related to other N4-like phages, especially of the Escherichia group. Although all these phages show a highly conserved genomic structure and partially strong similarities at the amino acid level, some differences could be identified. Those differences, e.g. the existence of specific genes for replication or host interaction in some N4-like phages, seem to be interesting targets for further examination of function and specific mechanisms, which might enlighten the mechanism of phage establishment in the host cell after infection.

Isolation and characterization of numerous novel phages targeting diverse strains of the ubiquitous and opportunistic pathogen Achromobacter xylosoxidans

The clinical relevance of nosocomially acquired infections caused by multi-resistant Achromobacter strains is rapidly increasing. Here, a diverse set of 61 Achromobacter xylosoxidans strains was characterized by MultiLocus Sequence Typing and Phenotype MicroArray technology. The strains were further analyzed in regard to their susceptibility to 35 antibiotics and to 34 different and newly isolated bacteriophages from the environment. A large proportion of strains were resistant against numerous antibiotics such as cephalosporines, aminoglycosides and quinolones, whereas piperacillin-tazobactam, ticarcillin, mezlocillin and imipenem were still inhibitory. We also present the first expanded study on bacteriophages of the genus Achromobacter that has been so far a blank slate with respect to phage research. The phages were isolated mainly from several waste water treatment plants in Germany. Morphological analysis of all of these phages by electron microscopy revealed a broad diversity with different members of the order Caudovirales, including the families Siphoviridae, Myoviridae, and Podoviridae. A broad spectrum of different host ranges could be determined for several phages that lysed up to 24 different and in part highly antibiotic resistant strains. Molecular characterisation by DNA restriction analysis revealed that all phages contain linear double-stranded DNA. Their restriction patterns display distinct differences underlining their broad diversity.

Achromobacter species endocarditis: A case report and literature review

Endocarditis due to Achromobacter species is a rare, yet serious, endovascular infection. Achromobacter species infective endocarditis is associated with underlying immunodeficiencies or prosthetic heart valves and devices. A case of prosthetic pulmonary valve endocarditis secondary to Achromobacter xylosoxidans subspecies denitrificans is described in the present report. This life-threatening infection was successfully treated with combined valve replacement and prolonged antibiotic therapy. A Medline/PubMed literature review of Achromobacter endocarditis was also performed. Achromobacter species are an uncommon, yet important, cause of nosocomial endocarditis. Given the significant associated morbidity and mortality, along with a high degree of intrinsic antibiotic resistance, Achromobacter species infective endocarditis remains a clinical treatment challenge.

Genetic and biochemical characterization of a novel metallo-β-lactamase, TMB-1, from an Achromobacter xylosoxidans strain isolated in Tripoli, Libya

An Achromobacter xylosoxidans strain from the Tripoli central hospital produced a unique metallo-β-lactamase, designated TMB-1, which is related to DIM-1 (62%) and GIM-1 (51%). bla(TMB-1) was embedded in a class 1 integron and located on the chromosome. The TMB-1 β-lactamase has lower k(cat) values than both DIM-1 and GIM-1 with cephalosporins and carbapenems. The K(m) values were more similar to those of GIM-1 than those of DIM-1, with the overall k(cat)/K(m) values being lower than those for GIM-1 and DIM-1.

Achromobacter xylosoxidans keratitis after contact lens usage

To report on Achromobacter xylosoxidans keratitis in two healthy patients who had worn contact lenses foran extended period of time. A 36-year-old female and a 21-year-old female visited our hospital with ocular pain and blurred vision. Both patients had a history of wearing soft contact lenses for over fve years with occasional overnight wear. At the initial presentation, a slit lamp examination revealed corneal stromal infiltrations and epithelial defects with peripheral neovascularization in both patients. Microbiological examinations were performed from samples of corneal scrapings, contact lenses, contact lens cases, and solution. The culture resulting from the samples taken from the contact lenses, contact lens cases, and solution were all positive for Achromobacter xylosoxidans. Confrming that the direct cause of the keratitis was the contact lenses, the frst patient was prescribed ceftazidime and amikacin drops sensitive to Achromobacter xylosoxidans. The second patient was treated with 0.3% gatifoxacin and fortifed tobramycin drops. After treatment, the corneal epithelial defects were completely healed, and subepithelial corneal opacity was observed. Two cases of Achromobacter xylosoxidans keratitis were reported in healthy young females who wore soft contact lenses. Achromobacter xylosoxidans should be considered a rare but potentially harmful pathogen for lens-induced keratitis in healthy hosts.

Achromobacter xylosoxidans infection presenting as a pulmonary nodule mimicking cancer

Achromobacter xylosoxidans is typically isolated from pulmonary sources, presenting as pneumonia in immunosuppressed individuals. We describe a novel clinical presentation of A. xylosoxidans infection presenting as multiple spiculated, pulmonary nodules mimicking cancer for which the patient underwent a wedge resection of the lung for diagnosis and staging of presumptive cancer.

Bilateral Achromobacter xylosoxidans keratitis after laser in situ keratomileusis

A 31-year-old man was referred to us 2 months after bilateral laser in situ keratomileusis (LASIK). On presentation, the corrected distance visual acuity was hand motion in the right eye and 20/25 in the left eye. Slitlamp examination showed a diffuse central stromal infiltrate, flap melting, and hypopyon in the right eye and marked interface opacities with crystal-like edges in the left eye. Flap lift and irrigation were performed. Because of the progressive keratitis, penetrating keratoplasty (PKP) was done in both eyes. Achromobacter xylosoxidans was isolated from both corneal buttons, and therapy was changed to chloramphenicol prednisolone eyedrops 8 times a day and intravenous meropenem 500 mg 3 times a day according to sensitivity testing. Two months after surgery, both transplants remained clear.