Microbiology of Eye Infections at the Massachusetts Eye and Ear: An 8-Year Retrospective Review Combined With Genomic Epidemiology.

PURPOSE: Ocular bacterial infections are important causes of morbidity and vision loss. Early antimicrobial therapy is necessary to save vision, but their efficacy is increasingly compromised by antimicrobial resistance (AMR). We assessed the etiology of ocular bacterial infections seen at Massachusetts Eye and Ear and investigated the molecular epidemiology and AMR profiles of contemporary isolates. DESIGN: Laboratory investigation. METHODS: We used a combination of phenotypic tests and genome sequencing to identify the predominant lineages of leading ocular pathogens and their AMR profiles. RESULTS: A total of 1601 isolates were collected from 2014 to 2021, with Staphylococcus aureus (n = 621), coagulase-negative staphylococci (CoNS) (n = 234), Pseudomonas aeruginosa (n = 213), Enterobacteriaceae (n = 167), and Streptococcus pneumoniae (n = 95) being the most common. Resistance was high among staphylococci, with methicillin resistance (MR) detected in 28% of S aureus and 39.8% of CoNS isolates. Multidrug resistance (MDR) was frequent among MR staphylococci (MRSA 60%, MRCoNS 76.1%). The population of S aureus isolates consisted mainly of 2 clonal complexes (CCs): CC8 (26.1%) and CC5 (24.1%). CC5 strains carried a variety of AMR markers, resulting in high levels of resistance to first-line therapies. Similarly, the population of ocular Staphylococcus epidermidis was homogenous with most belonging to CC2 (85%), which were commonly MDR (48%). Conversely, ocular S pneumoniae, P aeruginosa, and Enterobacteriaceae were often susceptible to first-line therapies and grouped into highly diverse genetic populations. CONCLUSION: Our data showed that ocular bacterial infections in our patient population are disproportionately caused by strains that are resistant to clinically relevant antibiotics and are associated with major epidemic genotypes with both community and hospital associations.

Hypopyon and White Cataract Due to an Intraocular Helminth.

We describe a case of a 29-year-old man with a history of intravenous drug use and vague history of eye trauma who presented with a hypopyon and white cataract in the right eye. He underwent pars plana vitrectomy and lensectomy; his anterior chamber aspirate revealed a single helminth on calcofluor stain. We suspect that his helminth infection may be secondary to unsanitary eating and drinking practices. As overall hygiene and dietary habits have improved during the years, parasitic helminth infections are relatively rare in nonendemic areas, especially in the nonpediatric population. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:168-171.].

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.

Staphylococcus aureus from ocular and otolaryngology infections are frequently resistant to clinically important antibiotics and are associated with lineages of community and hospital origins.

Staphylococcus aureus is an important human pathogen that causes serious antibiotic-resistant infections. Its population structure is marked by the appearance and dissemination of successful lineages across different settings. To begin understanding the population structure of S. aureus causing ocular and otolaryngology infections, we characterized 262 isolates by antimicrobial sensitivity testing and multilocus sequence typing (MLST). Methicillin-resistant S. aureus were subjected to SCCmec typing and Panton-Valentine leukocidin (PVL) screening. Although we detected a high level of genetic diversity among methicillin-sensitive (MSSA) isolates, (63 sequence types-STs), the population was dominated by five lineages: ST30, ST5, ST8, ST15 and ST97. Resistance to penicillin, erythromycin and clindamycin was common among the major MSSA lineages, with fluctuations markedly impacted by genetic background. Isolates belonging to the predominant lineage, ST30, displayed high rates of resistance to penicillin (100%), erythromycin (71%), and clindamycin (63%). Overall, 21% of the isolates were methicillin-resistant (MRSA), with an apparent enrichment among otitis and orbital cellulitis isolates (>40%). MRSA isolates belonged to 14 STs grouped in 5 clonal complexes (CC), however, CC5 (56.1%) and CC8 (38.6%) dominated the population. Most CC5 strains were SCCmec type II, and resembled the hospital-adapted USA100 clone. CC8 strains were SCCmec type IV, and 86% were positive for the PVL toxin, common features of the community-acquired clone USA300. CC5 strains harboring a SCCmec type IV, typical for the USA800 clone, comprised 15.5% of the population. USA100 strains were highly resistant to clindamycin, erythromycin and levofloxacin (100%), while USA300 strains were frequently resistant to erythromycin (89%) but displayed lower rates of resistance to levofloxacin (39%) and clindamycin (17%). Our data demonstrate that the ocular and otolaryngology S. aureus populations are composed of strains that are commonly resistant to clinically relevant antibiotics, and are associated with the major epidemic clonal complexes of both community and hospital origins.

Infectious endophthalmitis in Boston keratoprosthesis: incidence and prevention.

PURPOSE: To determine the cumulative worldwide incidence of infectious endophthalmitis and associated vision loss after Boston keratoprosthesis (B-KPro) Type I/II implantation and to propose both safe and inexpensive prophylactic antibiotic regimens. METHODS: Two retrospective methods were used to determine the incidence, visual outcomes and aetiologies of infectious endophthalmitis associated with the B-KPro divided per decade: (i) systematic review of the literature from 1990 through January 2013 and (ii) a surveillance survey sent to all surgeons who implanted B-KPros through 2010 with 1-year minimum follow-up. In addition, a single-Boston surgeon 20-year experience was examined. RESULTS: From 1990 through 2010, there were 4729 B-KPros implanted worldwide by 209 U.S. surgeons and 159 international surgeons. The endophthalmitis cumulative mean incidence declined from 12% during its first decade of use to about 3% during its second decade in the Unites States and about 5% internationally during the second decade. There remains a large incidence range both in the United States (1-12.5%) and internationally (up to 17%). Poor compliance with daily topical antibiotics is an important risk factor. While Gram-positive organisms remained dominant, fungal infections emerged during the second decade. CONCLUSIONS: Daily prophylactic topical antibiotics have dramatically reduced the endophthalmitis incidence. Although Gram-positive organisms are the most common aetiology, antimicrobials must be inclusive of Gram-negative organisms. Selection of prophylactic regimens should be tailored to local antibiotic susceptibility patterns, be cost-effective, and should not promote the emergence of antimicrobial resistance. An example of a broad-spectrum, low-cost prophylactic option for non-autoimmune patients includes trimethoprim/polymyxinB once daily.