Update on the Epidemiology and Antibiotic Resistance of Ocular Infections

Culture positivity and distribution of the conjunctival sac bacteria in the perioperative period of corneal refractive surgery

The objective of this study was to investigate the culture positivity and distribution of the conjunctival sac bacteria in the perioperative period of corneal refractive surgery. The selected time points of the perioperative period included before the use of antibiotic eye drops, before eye wash (after the use of antibiotic eye drops), after eye wash, and immediately after surgery. Conjunctival specimens obtained at the four time points were cultured to detect the positivity and distribution of bacteria. Before prophylactic antibiotic eye drops were administered, 49 eyes (50%) had positive bacterial culture results, with 45 isolates (91.8%) identified as Staphylococcus epidermidis. The culture positivity rates of the conjunctival sac specimens before eye wash, after eye wash, and immediately after surgery were 19.4%, 3.1%, and 4.1%, respectively. The difference was significant before and after the use of antibiotics and before and after eye wash (both P < 0.001). Staphylococcus epidermidis was the major pathogen in the conjunctival sac before corneal refractive surgery, and the culture positivity rate of the conjunctival bacteria was higher in males. Sixteen of 37 eyes (43.2%) with contact lenses had positive culture results, compared to 33 of 61 eyes (54.1%) without contact lenses (P > 0.05). The judicious preoperative use of antibiotic eye drops combined with the surgical sterile eye wash procedure maximised the removal of conjunctival sac bacteria. Skilled surgical manipulations generally did not increase the risk of infection.

Variations in irradiation energy and rose bengal concentration for photodynamic antimicrobial therapy of fungal keratitis isolates

The purpose is to assess the efficacy of rose bengal photodynamic antimicrobial therapy (PDAT) using different irradiation energy levels and photosensitizer concentrations for the inhibition of fungal keratitis isolates. Seven different fungi (Aspergillus fumigatus, Candida albicans, Curvularia lunata, Fusarium keratoplasticum, Fusarium solani, Paecilomyces variotii, and Pseudallescheria boydii) were isolated from patients with confirmed infectious keratitis. Experiments were performed in triplicate with suspensions of each fungus exposed to different PDAT parameters including a control, green light exposure of 5.4 J/cm2, 2.7 J/cm2 (continuous and pulsed), and 1.8 J/cm2 and rose bengal concentrations of 0.1%, 0.05%, and 0.01%. Plates were photographed 72 h after experimentation, and analysis was performed to assess fungal growth inhibition. PDAT using 5.4 J/cm2 of irradiation and 0.1% rose bengal completely inhibited growth of five of the seven fungal species. Candida albicans and Fusarium keratoplasticum were the most susceptible organisms, with growth inhibited with the lowest fluence and minimum rose bengal concentration. Fusarium solani, Pseudallescheria boydii, and Paecilomyces variotii were inhibited by lower light exposures and photosensitizer concentrations. Aspergillus fumigatus and Curvularia lunata were not inhibited by any PDAT parameters tested. Continuous and pulsed irradiation using 2.7 J/cm2 produced similar results. Rose bengal PDAT successfully inhibits the in vitro growth of five fungi known to cause infectious keratitis. Differences in growth inhibition of the various fungi to multiple PDAT parameters suggest that susceptibilities to PDAT are unique among fungal species. These findings support modifying PDAT parameters based on the infectious etiology.

The microbiological landscape and epidemiology of ocular infections in a multi-tier ophthalmology network in India: an electronic medical record driven analytics report

OBJECTIVE

To study the epidemiology and landscape of ocular infections in patients undergoing microbiological investigations across a multi-tier ophthalmology network in India.

METHODS

This cross-sectional hospital-based study included 15,822 patients in whom microbiology samples were analysed between September 2013 and December 2021. Ocular tissue of patients in whom a microbiology sample was processed in at least one eye were included. The data were collected using an indigenously developed electronic medical record system.

RESULTS

Among the 15,822 patients, bacteria (51.06%) was the most common aetiology followed by fungus (38.27%). The majority of the patients were male (68.10%) and adults (90.01%). The most common age group was during the sixth decade of life with 2,914 (18.42%) patients. The patients were more commonly from the lower socio-economic status (51.61%) and from the rural geography (46.82%). Majority of the specimens sent for microbiological analysis were corneal scrapings (68.61%) followed by vitreous (8.77%). The most common bacteria isolated was Staphylococcus aureus (14.45%) followed by Pseudomonas aeruginosa (12.53%) and among the fungus were Fusarium (30.53%) and Aspergillus species (29.86%). Acanthamoeba (1.26%) and Microsporidia (0.38%) accounted for a minority of the infections in the samples. Fungus (53.10%; p ≤ 0.00001) and virus (51.08%; p = 0.000673) aetiology was found to be significantly higher in patients presenting from the rural geography.

CONCLUSION

The most common aetiology of infection in ocular disease is bacterial but fungal infections also accounted for a significant proportion. The majority of the patients with ocular infections presented from the rural geography and from lower socio-economic status.

Dual Drug Loaded Lipid Nanocarrier Formulations for Topical Ocular Applications

Introduction

Untreated ocular infections can damage the unique fine structures of the eye with possible visual impairments and blindness. Ciprofloxacin (CIP) ophthalmic solution is prescribed as first-line therapy in ocular bacterial infections. Natamycin (NT) ophthalmic suspension is one of the progenitors in ocular antifungal therapy. Nanostructured lipid carriers (NLCs) have been widely examined for ocular penetration enhancement and distribution to deeper ocular tissues. The objective of the current study was to prepare NLCs loaded with a combination of CIP and NT (CIP-NT-NLCs) and embed them in an in-situ gelling system (CIP-NT-NLCs-IG). This novel formulation will target the co-delivery of CIP and NT for the treatment of mixed ocular infections or as empirical treatment in case of limited access to healthcare diagnostic services.

Methods

CIP-NT-NLC and CIP-NT-NLC-IG formulations were evaluated based on physicochemical characteristics, in vitro release, and ex vivo transcorneal permeation studies and compared against commercial CIP and NT ophthalmic eye drops.

Results and Discussion

NLCs formulation (0.1% CIP and 0.3% NT) showed particle size, polydispersity index, and zeta potential of 196.2 ± 1.2 nm, 0.43 ± 0.06, and −28.1 ± 1.4 mV, respectively. Moreover, CIP-NT-NLCs showed entrapment efficiency of 80.9 ± 2.9 and 98.7 ± 1.9% for CIP and NT, respectively. CIP-NT-NLCs-IGformulation with 0.2% w/v gellan gum demonstrated the most favorable viscoelastic characteristics for ocular application. CIP-NT-NLCs and CIP-NT-NLCs-IG formulations exhibited a sustained release pattern for both drugs over 24 h. Moreover, CIP-NT-NLCs and CIP-NT-NLC-IG formulations showed 4.0- and 2.2-folds, and 5.0- and 2.5-folds enhancement in ex vivo transcorneal permeability of CIP and NT, respectively, compared to the control formulations.

Conclusion

The results suggest that this dual nanoparticulate-based in-situ gelling drug delivery system can serve as a promising topical delivery platform for the treatment of ocular infections.

A Systematic Review of Multi-decade Antibiotic Resistance Data for Ocular Bacterial Pathogens in the United States

INTRODUCTION

Since 2009, the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study has been assessing in vitro antibiotic resistance for bacterial isolates sourced from ocular infections in the US. The main goal of this systematic review was to compare in vitro resistance data for ocular pathogens from published US studies with the most recently published data from the ARMOR study (2009-2018) and, where possible, to evaluate trends in bacterial resistance over time over all studies.

METHODS

A literature search was conducted using MEDLINE®, BIOSIS Previews®, and EMBASE^® databases (1/1/1995-6/30/2021). Data were extracted from relevant studies and antibiotic susceptibility rates for common ocular pathogens (Staphylococcus aureus, coagulase-negative staphylococci [CoNS], Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae), longitudinal changes in susceptibility, and multidrug resistance (MDR) were compared descriptively.

RESULTS

Thirty-two relevant studies were identified. High in vitro resistance was found among S. aureus and CoNS to fluoroquinolones, macrolides, and methicillin/oxacillin across studies, with high rates of MDR noted, specifically among methicillin-resistant staphylococci. Data from studies pre-dating or overlapping the early years of ARMOR reflected increasing rates of S. aureus resistance to fluoroquinolones, macrolides, methicillin/oxacillin, and aminoglycosides, while the ARMOR data suggested slight decreases in resistance to these classes between 2009 and 2018. Overall, methicillin-resistant S. aureus (MRSA) prevalence peaked from 2005 to 2015 with a possible decreasing trend in more recent years.

DISCUSSION AND CONCLUSIONS

Data from local and regional US datasets were generally consistent with data from the national ARMOR surveillance study. Continued surveillance of ocular bacterial pathogens is needed to track trends such as methicillin resistance and MDR prevalence and any new emerging antibiotic resistance phenotypes. Susceptibility data from ARMOR can inform initial choice of therapy, especially in practice areas where local antibiograms are unavailable.

Co-Existence of Certain ESBLs, MBLs and Plasmid Mediated Quinolone Resistance Genes among MDR E. coli Isolated from Different Clinical Specimens in Egypt

The emergence of multi-drug resistant (MDR) strains and even pan drug resistant (PDR) strains is alarming. In this study, we studied the resistance pattern of E. coli pathogens recovered from patients with different infections in different hospitals in Minia, Egypt and the co-existence of different resistance determinants. E. coli was the most prevalent among patients suffering from urinary tract infections (62%), while they were the least isolated from eye infections (10%). High prevalence of MDR isolates was found (73%) associated with high ESBLs and MBLs production (89.4% and 64.8%, respectively). bla_TEM (80%) and bla_NDM (43%) were the most frequent ESBL and MBL, respectively. None of the isolates harbored bla_KPC and bla_OXA-48 carbapenemase like genes. Also, the fluoroquinolone modifying enzyme gene aac-(6′)-Ib-cr was detected in 25.2% of the isolates. More than one gene was found in 81% of the isolates. Azithromycin was one of the most effective antibiotics against MDR E. coli pathogens. The high MAR index of the isolates and the high prevalence of resistance genes, indicates an important public health concern and high-risk communities where antibiotics are abused.

In Vitro Time-Kill of Common Ocular Pathogens with Besifloxacin Alone and in Combination with Benzalkonium Chloride

BACKGROUND

Besifloxacin ophthalmic suspension 0.6% (w/v%) contains benzalkonium chloride (BAK) as a preservative. We evaluated the in vitro time-kill activity of besifloxacin, alone and in combination with BAK, against common bacteria implicated in ophthalmic infections.

METHODS

The activity of besifloxacin (100 µg/mL), BAK (10, 15, 20, and 100 µg/mL), and combinations of besifloxacin and BAK were evaluated against isolates of Staphylococcus epidermidis (n = 4), Staphylococcus aureus (n = 3), Haemophilus influenzae (n = 2), and Pseudomonas aeruginosa (n = 2) in time-kill experiments of 180 min duration. With the exception of one S. aureus isolate, all of the staphylococcal isolates were methicillin- and/or ciprofloxacin-resistant; one P. aeruginosa isolate was ciprofloxacin-resistant. The reductions in the viable colony counts (log₁₀ CFU/mL) were plotted against time, and the differences among the time-kill curves were evaluated using an analysis of variance. Areas-under-the-killing-curve (AUKCs) were also computed.

RESULTS

Besifloxacin alone demonstrated ≥3-log killing of P. aeruginosa (<5 min) and H. influenzae (<120 min), and approached 3-log kills of S. aureus. BAK alone demonstrated concentration-dependent killing of S. epidermidis, S. aureus and H. influenzae, and at 100 µg/mL produced ≥3-log kills in <5 min against these species. The addition of BAK (10, 15, and 20 µg/mL) to besifloxacin increased the rate of killing compared to besifloxacin alone, with earlier 3-log kills of all species except P. aeruginosa and a variable impact on S. aureus. The greatest reductions in AUKC were observed among H. influenzae (8-fold) and S. epidermidis (≥5-fold). Similar results were found when the isolates were evaluated individually by their resistance phenotype.

CONCLUSIONS

In addition to confirming the activity of 100 µg/mL BAK as a preservative in the bottle, these data suggest that BAK may help besifloxacin to achieve faster time-kills on-eye in the immediate timeframe post-instillation before extensive dilution against bacterial species implicated in ophthalmic infections, including drug-resistant S. epidermidis. Greater killing activity may help prevent resistance development and/or help treat resistant organisms.

Evidence of Antibiotic Resistance from Population-Based Studies: A Narrative Review

The 20th century witnessed the dawn of the antibiotic revolution and is now facing the rising phenomenon of antibiotic resistance. In this narrative review, we aim to describe antibiotic resistance in clinical practice settings through population-based studies from different countries reporting the role of misuse of antibiotics in the development of resistance and the clinical and economic burden associated. The misuse of antibiotics was documented in the wide population as well as in hospitals and care facilities. It was mainly reported as over-use and inappropriate prescribing. Improper dosage regimens and longer treatment duration were regarded as pivotal factors related to antibiotic resistance; the emerging strategy of "antibiotic-de-escalation" could be the key to overcome these issues. The investigation of the self-medication attitude revealed widespread antibiotic use without following medical instructions or medical consultation. Moreover, several studies established the association of antibiotic resistance with increased risk of longer hospitalizations and mortality, highlighting the heavy clinical and economic burden of this phenomenon. In this narrative review, the widespread inappropriate use of antibiotics emerged as one of the main causes of antibiotic resistance, which negative outcomes call for the development of antibiotic stewardship programs and global surveillance networks.

Trends in Antibiotic Resistance Among Ocular Microorganisms in the United States From 2009 to 2018

Question

What are the antibiotic resistance profiles and trends among common ocular pathogens across the United States?

Findings

In this cross-sectional study of more than 6000 ocular isolates of Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae collected between 2009 and 2018, methicillin resistance and multidrug resistance were prevalent among staphylococci. Antibiotic resistance profiles were mostly unchanged during 10 years.

Meaning

These in vitro antibiotic resistance data may assist clinicians in selecting appropriate antibiotics for treatment of ocular infections.

Importance

Antibiotic resistance in ocular infections can affect treatment outcomes. Surveillance data on evolving antibacterial susceptibility patterns inform the treatment of such infections.

Objective

To assess overall antibiotic resistance profiles and trends among bacterial isolates from ocular sources collected during 10 years.

Design, Setting, and Participants

This cross-sectional study of longitudinal data from the ongoing, nationwide, prospective, laboratory-based surveillance study, the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study, included clinically relevant isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae cultured from patients with ocular infections at US centers from January 1, 2009, to December 31, 2018.

Main Outcomes and Measures

Minimum inhibitory concentrations were determined for various combinations of antibiotics and species. Odds ratios (ORs) were determined for concurrent antibiotic resistance; analysis of variance and χ² tests were used to evaluate resistance rates by patient age and geographic region; Cochran-Armitage tests identified changing antibiotic susceptibility trends over time.

Results

A total of 6091 isolates (2189 S aureus, 1765 CoNS, 590 S pneumoniae, 767 P aeruginosa, and 780 H influenzae) from 6091 patients were submitted by 88 sites. Overall, 765 S aureus (34.9%) and 871 CoNS (49.3%) isolates were methicillin resistant and more likely to be concurrently resistant to macrolides (azithromycin: S aureus: OR, 18.34 [95% CI, 13.64-24.67]; CoNS: OR, 4.59 [95% CI, 3.72-5.66]), fluoroquinolones (ciprofloxacin: S aureus: OR, 22.61 [95% CI, 17.96-28.47]; CoNS: OR, 9.73 [95% CI, 7.63-12.40]), and aminoglycosides (tobramycin: S aureus: OR, 18.29 [95% CI, 13.21-25.32]; CoNS: OR, 6.28 [95% CI, 4.61-8.56]) compared with methicillin-susceptible isolates (P < .001 for all). Multidrug resistance was observed among methicillin-resistant S aureus (577 [75.4%]) and CoNS (642 [73.7%]) isolates. Antibiotic resistance among S pneumoniae isolates was highest for azithromycin (214 [36.3%]), whereas P aeruginosa and H influenzae isolates showed low resistance overall. Differences in antibiotic resistance were found among isolates by patient age (S aureus: F = 28.07, P < .001; CoNS: F = 11.46, P < .001) and geographic region (S aureus: F = 8.03, P < .001; CoNS: F = 4.79, P = .003; S pneumoniae: F = 8.14, P < .001; P aeruginosa: F = 4.32, P = .005). Small changes in antibiotic resistance were noted over time (≤2.5% per year), with decreases in resistance to oxacillin/methicillin (oxacillin: −2.16%; 95% CI, −3.91% to −0.41%; P < .001) and other antibiotics among S aureus isolates, a decrease in ciprofloxacin resistance among CoNS (−1.38%; 95% CI, −2.24% to −0.52%; P < .001), and an increase in tobramycin resistance among CoNS (0.71%; 95% CI, –0.29% to 1.71%; P = .03). Besifloxacin retained consistently low minimum inhibitory concentrations.

Conclusions and Relevance

Antibiotic resistance may be prevalent among staphylococcal isolates, particularly among older patients. In this study, a few small differences in antibiotic resistance were observed by geographic region or longitudinally.

Topical antibiotic therapy in eye infections - myths and certainties in the era of bacterial resistance to antibiotics

Globally, the alarming increase in the rate of antibiotic (AB) resistance of bacteria is currently considered one of the 7 major threats to the human race along with terrorism, nuclear proliferation and pollution. Judicious use of AB by physicians in all medical and surgical specialties is essential to limit the extent of resistance to AB. In Europe, Romania ranks among the first in terms of the rate of resistance to AB of the main bacteria involved in eye infections (EI). The principles of a judicious antibiotic therapy in ophthalmology are: performing the bacteriological determinations necessary to establish the bacterium involved in EI and its sensitivity to AB; avoiding the treatment of viral infections with AB; knowledge of the local rate of resistance of bacteria to AB; first choice of an AB with a spectrum appropriate to the aetiology of EI; the chosen AB must penetrate well into the eye tissues; using the local route of administration whenever possible; avoiding sub-dosing and shortening the duration of antibiotic therapy; abandoning the "myth" that a "in vitro" bactericidal AB would be inherently more clinically effective ("in vivo") than a bacteriostatic AB; requesting the consultation of infectious diseases for EI with AB multidrug-resistant bacteria. The available ophthalmic topics contain antibiotics from the following classes: aminoglycosides, fluoroquinolones, chloramphenicol, glycopeptides, polymyxins, etc. The increase in the fluoroquinolone resistance rate of the bacteria involved in EI has recently led to the recommendation that, in the absence of the antibiogram, it is best to avoid first-line antibiotic therapy with topical fluoroquinolones alone in keratitis. Abbreviations: AB = antibiotic, AG = aminoglycosides, AUC = area under the curve, Cf = chloramphenicol, Cmax = maximum concentration in tears, CNS = central nervous system, CSF = cerebrospinal fluid, DNA = deoxyribonucleic acid, ECDC = European Centre for Disease Prevention and Control, EI = eye infections, ENT = ear, nose and throat, EU = European Union, FQ = fluoroquinolones, HSV = Herpes simplex virus, MBC = minimum bactericidal concentration, MIC = minimum inhibitory concentration, MRSA = methicillin-resistant S. aureus, MRSE = methicillin-resistant S. epidermidis, MSSA = methicillin-sensitive S. aureus, MSSE = methicillin-sensitive S. epidermidis, PCR = polymerase chain reaction, S = sulfonamides, SPC = summary of product characteristics, USA = United States of America, VZV = Varicella zoster virus.

Ciprofloxacin Loaded Nanostructured Lipid Carriers Incorporated into In-Situ Gels to Improve Management of Bacterial Endophthalmitis

Bacterial endophthalmitis (BE) is a potentially sight-threatening inflammatory reaction of the intraocular fluids or tissues caused by bacteria. Ciprofloxacin (CIP) eye drops are prescribed as first-line therapy in BE. However, frequent administration is necessary due to precorneal loss and poor ocular bioavailability. The objective of the current research was to prepare CIP containing nanostructured lipid carriers (CIP-NLCs) loaded an in situ gel system (CIP-NLC-IG) for topical ocular administration for enhanced and sustained antibacterial activity in BE treatment. CIP-NLCs were prepared by the hot homogenization method and optimized based on physicochemical characteristics and physical stability. The optimized CIP-NLC formulation was converted into CIP-NLC-IG with the addition of gellan gum as a gelling agent. Furthermore, optimized CIP-NLC and CIP-NLC-IG were evaluated for in vitro release and ex vivo transcorneal permeation studies, using commercial CIP ophthalmic solution (CIP-C) as the control. The optimized CIP-NLC formulation showed particle size, polydispersity index, zeta potential, assay and entrapment efficiency of 193.1 ± 5.1 nm, 0.43 ± 0.01, -32.5 ± 1.5 mV, 99.5 ± 5.5 and 96.3 ± 2.5%, respectively. CIP-NLC-IG with 0.2% w/v gellan gum showed optimal viscoelastic characteristics. The in vitro release studies demonstrated sustained release of CIP from CIP-NLC and CIP-NLC-IG formulations over a 24 h period. Transcorneal flux and permeability increased 4 and 3.5-fold, and 2.2 and 1.9-fold from CIP-NLC and CIP-NLC-IG formulations, respectively, when compared to CIP-C. The results demonstrate that CIP-NLC-IG could be considered as an alternate delivery system to prolong the residence time on the ocular surface after topical administration. Thus, the current CIP ophthalmic formulations may exhibit improved ocular bioavailability and prolonged antibacterial activity, which may improve therapeutic outcomes in the treatment of BE.

Antibiotic resistance among ocular pathogens: current trends from the ARMOR surveillance study (2009-2016)

BACKGROUND

The Antibiotic Resistance Monitoring in Ocular micRoorganisms study is an ongoing surveillance study that tracks antibiotic resistance among bacterial isolates from ocular infections across the United States. We report antibiotic resistance rates and trends from 2009 through 2016.

MATERIALS AND METHODS

Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae from various ocular infections were obtained from participating United States centers. Isolates were sent to a central laboratory for determination of antibiotic resistance profiles. Minimum inhibitory concentrations were determined by broth microdilution according to the Clinical and Laboratory Standards Institute for drugs from more than ten antibiotic classes, and isolates were classified as susceptible or resistant based on systemic breakpoints, wherever available. Resistance rates were also evaluated based on decade of patient life and longitudinally over the 8-year time period.

RESULTS

A total of 1,695 S. aureus, 1,475 CoNS, 474 S. pneumoniae, 586 H. influenzae, and 599 P. aeruginosa were collected from 87 sites. Resistance was high among staphylococci and pneumococci, with methicillin resistance detected in 621 (36.6%) S. aureus and 717 (48.6%) CoNS isolates. Multidrug resistance (≥3 drug classes) was observed among staphylococci, particularly in methicillin-resistant (MR) isolates (MR S. aureus [MRSA]: 76.2%; MR CoNS [MRCoNS]: 73.5%). Differences in methicillin resistance among staphylococci were observed based on patient age, with higher rates observed in older patients (P<0.0001). For certain organism-antibiotic combinations, there were significant changes in resistance over time, including a decrease in methicillin resistance among S. aureus (but not CoNS); no notable trends were observed for S. pneumoniae.

CONCLUSION

Antibiotic resistance was prevalent among gram-positive organisms, and MR staphylococcal isolates were more likely to be multidrug resistant. Although a small decrease in methicillin resistance was observed among S. aureus over time, the continued high prevalence of in vitro methicillin resistance should be considered when treating patients with ocular infections.

Antibiotic Resistance Among Pediatric-Sourced Ocular Pathogens: 8-Year Findings From the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) Surveillance Study

BACKGROUND

The Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study is a nationwide longitudinal antibiotic resistance surveillance program specific to bacterial pathogens commonly encountered in ocular infections. We evaluated in vitro resistance rates and trends among isolates obtained from pediatric patients (≤17 years of age).

METHODS

Clinical centers across the United States were invited to submit ocular isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa to a central laboratory. Minimum inhibitory concentrations for various antibiotic classes were determined by broth microdilution per Clinical and Laboratory Standards Institute guidelines and interpreted as susceptible, intermediate or resistant based on available breakpoints. Longitudinal trends were analyzed using a Cochran-Armitage test for linear trends in a proportion.

RESULTS

Of 4829 isolates collected from January 2009 to December 2016, 995 isolates, sourced primarily from hospitals and referral centers, were obtained from pediatric patients (n = 286 H. influenzae, n = 284 S. aureus, n = 213 CoNS, n = 150 S. pneumoniae and n = 62 P. aeruginosa). With few exceptions, P. aeruginosa and H. influenzae were generally susceptible to the antibiotics tested. Of S. aureus and CoNS isolates, respectively, 56% and 72% were resistant to azithromycin and 24% and 47% were methicillin-resistant (MR); concurrent resistance to other drug classes and multidrug resistance (≥3 drug classes) were prevalent among MR staphylococci. Of S. pneumoniae isolates, 38% and 35% demonstrated resistance to azithromycin and penicillin, respectively. Besifloxacin had the lowest minimum inhibitory concentration against the Gram-positive isolates.

CONCLUSIONS

These in vitro data suggest antibiotic resistance is common among staphylococcal and pneumococcal isolates collected from pediatric patients with ocular infections. Methicillin resistance was prevalent among staphylococci with many strains demonstrating multidrug resistance. These findings may not be representative of resistance trends in community-based practices.

Antibiotic Resistance Rates by Geographic Region Among Ocular Pathogens Collected During the ARMOR Surveillance Study

Introduction

The Antibiotic Resistance Monitoring in Ocular micRoorganisms (ARMOR) study is an ongoing nationwide surveillance program that surveys in vitro antibiotic resistance rates and trends among ocular bacterial pathogens. We report resistance rates by geographic region for isolates collected from 2009 through 2016.

Methods

Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa isolates from ocular infections were collected at clinical centers across the US and categorized by geographic region based on state. Minimum inhibitory concentrations (MICs) for various antibiotics were determined at a central laboratory, and isolates were classified as susceptible or resistant based on established breakpoints. Geographic differences in methicillin resistance among staphylococci were evaluated by χ² test with multiple comparisons, whereas geographic differences in mean percentage antibiotic resistance were evaluated by one-way analyses of variance and Tukey’s test.

Results

Overall, 4829 isolates (Midwest, 1886; West, 1167; Northeast, 1143; South, 633) were evaluated. Across all regions, azithromycin resistance was high among S. aureus (49.4–67.8%), CoNS (61.0–62.8%), and S. pneumoniae (22.3–48.7%), whereas fluoroquinolone resistance ranged from 26.1% to 47.8% among S. aureus and CoNS. Across all regions, all staphylococci were susceptible to vancomycin; besifloxacin MICs were similar to those of vancomycin. Geographic differences were observed for overall mean resistance among S. aureus, S. pneumoniae, and P. aeruginosa isolates (p ≤ 0.005); no regional differences were found among CoNS and H. influenzae isolates. Methicillin resistance in particular was higher among S. aureus isolates from the South and CoNS isolates from the Midwest (p ≤ 0.006).

Conclusion

This analysis of bacterial isolates from the ARMOR study demonstrated geographic variation in resistance rates among ocular isolates, with greater in vitro resistance apparent in the South and Midwest for some organisms. These data may inform clinicians in selecting appropriate treatment options for ocular infections.

Funding

Bausch & Lomb, Inc.

Pharmacoepidemiological Observational Study of Antimicrobial Use in Outpatients of Ophthalmology Department in North Indian Population

Background

Recognition of drug usage patterns provides the basis for improving safety and plummeting risks associated with their use. Thus, this study was undertaken to explore the drug usage pattern in ophthalmology with an emphasis on antimicrobial use at a tertiary care teaching hospital.

Materials and Methods

An observational study was conducted in the Department of Ophthalmology, Hakeem Abdul Hameed Centenary Hospital, Jamia Hamdard, New Delhi, India for 9 months. Newly registered patients visiting the Outpatient Department for curative complaints were included. All drugs prescribed were recorded, including dose, route, dosage form, frequency of administration, indications for prescription, and duration of therapy, and the data was audited using the indicators prescribed by the World Health Organization.

Result

A total of 600 prescriptions were analyzed. The number of drugs prescribed was 1097 with an average drug per prescription being 1.8. The most common disorders diagnosed were infective conjunctivitis (21.5%) followed by stye (5.5%). Drugs were prescribed in different dosage forms with eye drops (72.6%) being the most common. Drugs were predominantly prescribed by brand name (100%). Antimicrobials (44.7%) were the most commonly prescribed drugs followed by lubricants (17.5%). Moxifloxacin (53.5%) was the most commonly prescribed antimicrobial agent. Of the antimicrobials prescribed, 89.6% were prescribed topically. Average total cost per prescription was 113 INR.

Conclusion

The study concludes with an overall impression of rational prescription in terms of prescribing in consensus with the recommended treatment protocol of ocular diseases. Nevertheless, health-care professionals should be encouraged to prescribe by generic name. Creating awareness regarding selection of drugs from essential drug list to reduce the drug cost is the need of the hour. Last but not least, updating knowledge regarding appropriate antimicrobial use and the development of discreet strategies for their use should be implemented to steer clear of antimicrobial resistance.

Bacteria induce autophagy in a human ocular surface cell line

Autophagy protects cells from intracellular pathogens, but can be exploited by some infectious agents to their benefit. Currently it is not known if bacteria induce autohpagy in cells of the cornea. The goal of this study was to develop an ocular surface autophagy reporter cell line and determine whether ocular bacterial pathogens influence host responses through autophagy induction. The cell line was made using lentivirus transduction of an LC3-GFP fusion protein in human corneal limbal epithelial (HCLE) cells. LC3-GFP puncta in HCLEs were induced by rapamycin and ammonium chloride treatments, and prevented by the autophagy inhibitors 3-methyladenine (3'MA) and bafilomycin. Importantly, secretomes from Escherichia coli, Serratia marcescens, Staphylococcus aureus, methicillin sensitive (MSSA) and resistant (MRSA), were found to induce autophagy, whereas other bacteria, including Acinetobacter baumannii, Achromobacter xylosoxidans, Enterococcus faecalis, Klebsiella pneumoniae, Moraxella sp., and Stenotrophomonas maltophilia, did not. Our data indicates differences between tested ocular isolates of MRSA and MSSA in the activation of autophagy. HCLEs treated with 3'MA were slightly more susceptible to cytotoxic factors produced by S. marcescens and MRSA keratitis isolates, by contrast, bafilomycin A1 treatment caused no difference. This work demonstrates the successful development and validation of an autophagy reporter corneal cell line and indicates differences between ocular bacterial isolates in the activation of autophagy.

Bacterial profile of ocular infections: a systematic review

BACKGROUND

Bacteria are the major contributor of ocular infections worldwide. Ocular infections, if left untreated, can damage the structures of the eye with possible blindness and visual impairments. This work was aimed to review the bacterial profile of ocular infections.

METHODS

Literature search was made in different electronic databases; the review was systematically made to get concrete findings.

RESULTS

As far as this review, Staphylococcus aureus, Coagulase negative Staphylococci, Streptococcus pneumoniae and Pseudomonas aeruginosa are the leading isolates in ocular infections. Frequent pathogens of the respective clinical diagnose include Staphylococci, Streptococcus pyogenes and Pseudomonas aeruginosa in blepharitis; Staphylococci, Streptococus pneumoniae, Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli in Conjunctivitis; Staphylococci, P. aeruginosa and E. coli in dacryocystitis; Coagulase negative Staphylococci, Pseudomonas aeruginosa and Staphylococcus aureus in keratitis; Streptococcus viridians, Streptococcus pneumoniae and Coagulase negative Staphylococci in endophthalmitis diagnoses. Endogenous endophthalmitis is associated with Klebsiella pneumoniae whereas Coagulase negative Staphylococci and Bacillus spp. are common causes of post-operative and post-traumatic endophthalmitis. However, the predominant pathogens may not be exactly same in all areas of the world, in the United States for instance, Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae are the major causes of conjunctivitis.

CONCLUSION

Gram positive bacteria are the major contributor of bacterial ocular infections. The distribution and proportion of bacterial isolates among clinical diagnoses varied but without exclusive anatomical restriction. To mitigate the burden of bacterial ocular infections, physicians should regard on risk reduction and comply with etiologic approach of diagnosis.

Baerveldt Scleral Patch Graft Abscess Secondary to Coagulase-Negative Staphylococcus

We report the case of a 69-year-old female who underwent a Baerveldt implant placement for severe-stage primary open-angle glaucoma and developed a bacterial infection of the conjunctiva and abscess of the scleral patch graft with subsequent tube exposure. The infection was identified 3 weeks postoperatively and a topical antibiotic was immediately initiated. A concurrent systemic staphylococcal infection was discovered by an outside physician and oral cephalexin was initiated. Despite antibiotic treatment, the conjunctival erosion progressed, and tube revision was required. Culture of the abscess revealed coagulase-negative Staphylococcus. As alluded to above, the patient also had multiple abscesses on the skin that cultured positive for Staphylococcus aureus. To our knowledge, this is the first case in the literature of coagulase-negative Staphylococcus causing an early postoperative abscess of the scleral patch graft following glaucoma drainage device placement.