Antibiotic resistance in ocular bacterial pathogens

Bibliometric analysis of publication trends on ocular hygiene and infections in the past two decades

Background

Ocular hygiene encompasses a spectrum of measures to initiate and maintain adequate ocular cleanliness to prevent eye infections and their further transmission. These infections affect all age groups and can lead to severe complications such as blindness. Nearly 1 billion cases could have been prevented out of over 2.2 billion people that are visually impaired worldwide. This bibliometric analysis focuses on the papers published on ocular hygiene and infections.

Methods

We searched in the Scopus database from 2004 to 2024. After manual screening, a list of the 100 most-cited original articles was obtained, which was analysed for various factors, including temporal trends, subject areas, authorship patterns, country of origin, funding bodies, etc.

Results

There has been a gradual decline over the past two decades in the number of publications. The United States was affiliated with the highest number of publications (n=61), followed by The United Kingdom (n=12) and Gambia (n=8). Several authors had 4 or more publications, with the highest number of publications by Rouse, B. T. (n=14). The American Journal of Ophthalmology takes the lead with 15 publications, while the National Eye Institute (n=23) was the leading funding body. Examination of institutional contributions shows that The University of Tennessee, Knoxville and UT College of Veterinary Medicine stand out with twelve publications each. Nearly half the publications belong to the field of medicine. However, significant publications also come from the fields Neuroscience, Microbiology and Immunology, Biochemistry, Genetics and Molecular Biology, etc. These findings highlight that there is great potential to conduct research to propagate ocular hygiene to prevent adverse effects of infections.

Susceptibility of Ocular Surface Bacteria to Various Antibiotic Agents in a Romanian Ophthalmology Clinic

Periodic assessment of bacterial contamination is necessary as it allows proper guidance in cases of eye infections through the use of appropriate antibiotics. Due to the extensive use of antibiotic treatment, many strains of the microbiota that cause infections are resistant to the usual ophthalmic antibiotics. The present study provides an updated assessment of the susceptibility of Gram-positive and Gram-negative bacteria found on the ocular surface to the most commonly used antibiotic agents in patients undergoing cataract surgery. A total of 993 patients were included in the study with ages between 44 and 98 years old. Conjunctival cultures were collected 7 days before cataract surgery. The response of Gram-positive and Gram-negative bacteria to various antibiotic classes, such as glycopeptides, cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, phenicols, tetracyclines, rifamycins, macrolides and penicillins, was assessed. From the tested antibiotics, vancomycin had 97.8% efficacy on Gram-positive bacteria. In the cephalosporin category, we observed a high level of resistance of the cefuroxime for both Gram-positive and negative bacteria. Antibiotics that have more than 90% efficacy on Gram-positive bacteria are meropenem, imipenem, netilmicin, amikacin and rifampicin. On Gram-negative bacteria, we found 100% efficacy of all tested fluoroquinolones, i.e., aminoglycosides (except for tobramycin), doxycycline, azithromycin, clarithromycin and chloramphenicol. The current study illustrates patterns of increased resistance in certain bacteria present on the ocular surface to some of the commonly used antibiotics in ophthalmological clinical practice. One such revealing example is cefuroxime, which has been highly used as an intracameral antibiotic for the prevention of bacterial endophthalmitis after cataract surgery.

Antibiotic resistance in ocular bacterial infections: an integrative review of ophthalmic chloramphenicol

INTRODUCTION

Chloramphenicol is a broad-spectrum antibiotic widely used for treating ophthalmic infections, but concerns about rising bacterial resistance to chloramphenicol have been observed due to its frequent use as an over-the-counter medication. This review assessed the common ophthalmic bacterial pathogens, their chloramphenicol resistance mechanisms, and rates of drug resistance.

METHODS

PubMed and Google Scholar databases were searched for relevant publications from the years 2000 to 2022, bordering on ophthalmic bacterial infections, chloramphenicol susceptibility profiles, and drug resistance mechanisms against chloramphenicol. A total of 53 journal publications met the inclusion criteria, with data on the antibiotic susceptibility profiles available in 44 of the reviewed studies, which were extracted and analyzed.

RESULTS

The mean resistance rates to chloramphenicol from antibiotic susceptibility profiles varied between 0% and 74.1%, with the majority of the studies (86.4%) showing chloramphenicol resistance rates below 50%, and more than half (23 out of 44) of the studies showed resistance rates lower than 20%. The majority of the publications (n = 27; 61.4%) were from developed nations, compared to developing nations (n = 14; 31.8%), while a fraction (n = 3; 6.8%) of the studies were regional cohort studies in Europe, with no country-specific drug resistance rates. No pattern of cumulative increase or decrease in ophthalmic bacterial resistance to chloramphenicol was observed.

CONCLUSIONS

Chloramphenicol is still active against ophthalmic bacterial infections and is suitable as a topical antibiotic for ophthalmic infections. However, concerns remain about the drug becoming unsuitable in the long run due to some proof of high drug resistance rates.

Effect of Antibiotic Eye Drops on the Nasal Microbiome in Healthy Subjects—A Pilot Study

Background: Antibiotic eye drops are frequently used in clinical practice. Due to the anatomical connection via the nasolacrimal duct, it seems possible that they have an influence on the nasal/pharyngeal microbiome. This was investigated by using two different commonly used antibiotic eye drops. Methods: 20 subjects were randomized to four groups of five subjects receiving eye drops containing gentamicin, ciprofloxacin, or, as controls, unpreserved povidone or benzalkonium chloride-preserved povidone. Nasal and pharyngeal swabs were performed before and after the instillation period. Swabs were analyzed by Illumina next-generation sequencing (NGS)-based 16S rRNA analysis. Bacterial culture was performed on solid media, and bacterial isolates were identified to the species level by MALDI-TOF MS. Species-dependent antimicrobial susceptibility testing was performed using single isolates and pools of isolates. Results: Bacterial richness in the nose increased numerically from 163 ± 30 to 243 ± 100 OTUs (gentamicin) and from 114 ± 17 to 144 ± 45 OTUs (ciprofloxacin). Phylogenetic diversity index (pd) of different bacterial strains in the nasal microbiome increased from 12.4 ± 1.0 to 16.9 ± 5.6 pd (gentamicin) and from 10.2 ± 1.4 to 11.8 ± 3.1 pd (ciprofloxacin). Unpreserved povidone eye drops resulted in minimal changes in bacterial counts. Preservative-containing povidone eye drops resulted in no change. A minor increase (1–2-fold) in the minimal inhibitory concentration (MIC) was observed in single streptococcal isolates. Conclusions: Antibiotic eye drops could affect the nasal microbiome. After an instillation period of seven days, an increase in the diversity and richness of bacterial strains in the nasal microbiome was observed.

Bacterial Profile of External Ocular Infections, Its Associated Factors, and Antimicrobial Susceptibility Pattern among Patients Attending Karamara Hospital, Jigjiga, Eastern Ethiopia

Background

External ocular infection is a global public health problem. Frequently, bacteria cause an ocular infection that ranges from morbidity to loss of vision. The increasing bacterial resistance in ocular infections leads to the risk of treatment failure with possibly serious consequences.

Objective

The study aimed to assess the bacterial profile of external ocular infections, their associated factors, and antimicrobial susceptibility pattern among patients admitted to Karamara hospital, Jigjiga, Eastern Ethiopia.

Method

Institutional-basedcross-sectional study was conducted on 288 conveniently selected patients among patients admitted to Karamara hospital from May 1 to June 30, 2020. Data were collected using a structured questionnaire. The ocular sample was collected and cultured in the appropriate culture media and identified using a series of biochemical tests. Antimicrobial susceptibility testing of isolates was performed by using the disk diffusion method. Data were double entered onto EpiData version 3.1 then exported to SPSS version 20 and analyzed to calculate descriptive frequency and odds ratio, and p value ≤0.05 was taken as the significant value.

Result

The prevalence of bacterial infection in external ocular samples was 62.2% (95% CI: 56.6%, 68.4%). Out of the 179 isolates, the majority of the bacterial isolates (87.7%) were Gram-positive. Staphylococcus aureus (53.1%) was the predominant isolate. Using soap for washing the face (AOR = 0.43; 95% CI: 0.29, 0.95), having diabetes mellitus (AOR = 3.11; 95% CI: 1.45, 6.75), and history of hospitalization (AOR = 2.82; 95% CI: 1.44, 5.54) were significantly associated with external ocular infection. Most (95.5%) of the Gram-positive bacteria showed resistance to penicillin, but they were susceptible to vancomycin, clindamycin, and ciprofloxacin.

Conclusion

The study showed a high prevalence of bacterial infections with the predominant isolate was S. aureus. Penicillin-resistant bacteria were identified among Gram-positive bacterial isolates. Soap usage, hospitalization, and diabetes mellitus were associated with the infection. Antibiotics that were susceptible to the specific bacteria should be used as a drug of choice and using soap for washing the face is advisable to protect against external ocular infection.

Prevalence and Molecular Characterization of Metallo β-Lactamase Producing Gram-Negative Pathogens Causing Eye Infections

Purpose:

Metallo β-lactamases (MβL) production is a worldwide problem, particularly in gram-negative bacteria. As scanty data is available on the prevalence of MBL, the present study is being undertaken to determine the prevalence, antibacterial sensitivity patterns, and molecular characterization of MβL associated resistant genes in gram-negative bacteria isolated from ocular infections.

Material and Methods

At a tertiary eye care center in south India, 359 gram-negative pathogens, 200 isolates from eye infections, and 159 isolates from normal flora of the eye were studied. A gold standard microbiology method was used to identify the isolates. An antibiotic double disc synergy test and a combination disc test were used to detect MβL production. Multiplex PCR was used to investigate the molecular characteristics of the MβL encoding genes blaVIM, blaIMP, and blaNDM.

Results

Of the 359 gram-negative bacterial pathogens, Pseudomonas aeruginosa 108 (30.1%) and Enterobacter agglomerans 46 (12.8%) were commonly isolated. High prevalence of P. aeruginosa 81% (17 strains) was detected as an MβL producer and it shows 100% resistance to 2nd and 3rd generation cephalosporins and meropenem. Multiplex PCR detected only the blaVIM gene in 56 (28%) of various eye infections and 27 (17%) of normal flora of the gram-negative bacteria (GNB). The blaVIM gene is detected predominantly in 51.8% of keratitis and 21.4% of postoperative endophthalmitis. High prevalence of the gene was detected in P. aeruginosa 42.9% (24 of 56) and Alcaligens denitrificans 10.7% (6 of 56) from eye infections. Whereas, in the control group, P. aeruginosa and E. coli each had 14.8% (4 of 27) that were shown positive.

Conclusion

The emerging MβLs mediated resistance among P. aeruginosa is a challenging task for ophthalmologists, especially in patients with endophthalmitis and bacterial keratitis. This local knowledge will aid in advising appropriate antibiotic use and avoiding unnecessary antibiotic prescriptions, which are highly warranted.

Prevalence and Antimicrobial Resistance of Causative Agents to Ocular Infections

Bacterial ocular infections are a worldwide health problem and, if untreated, can damage the structure of the eye and contribute to permanent disability. Knowledge of the prevalence and antimicrobial susceptibility patterns of the main causative agents involved in ocular infections is necessary for defining an optimal antibiotic therapy. The aim of this study was to analyse bacterial species involved in ocular infections and the antimicrobial susceptibility patterns. Conjunctival swab samples were collected from patients with bacterial conjunctivitis at the University Hospital San Giovanni di Dio e Ruggi d’Aragona between January 2015 and December 2019. The identification and antibiotic sensitivity tests were performed using the VITEK 2 system. A total of 281 causative agents of ocular infections were isolated, 81.8% of which were Gram-positive bacteria. Coagulase-negative staphylococci (CoNS) were the most commonly isolated species among Gram-positive bacteria, followed by Staphylococcus aureus. In contrast, Pseudomonas spp. and Escherichia coli were the main species isolated among Gram-negative bacteria (18.2%). Overall, linezolid, teicoplanin, tigecycline and vancomycin were the most effective antimicrobials. Analysis of resistance rates over time highlighted increasing resistance for azithromycin, clarithromycin and erythromycin among CoNS, and clindamycin and erythromycin among Staphylococcus aureus. This study has identified the profiles of the major pathogens involved in ocular infection and their susceptibility patterns, which will help improve the treatments and the choice of antibiotics in ocular infections.

Susceptibility of Ocular Staphylococcus aureus to Antibiotics and Multipurpose Disinfecting Solutions

Staphylococcus aureus is a frequent cause of ocular surface infections worldwide. Of these surface infections, those involving the cornea (microbial keratitis) are most sight-threatening. S. aureus can also cause conjunctivitis and contact lens-related non-infectious corneal infiltrative events (niCIE). The aim of this study was to determine the rates of resistance of S. aureus isolates to antibiotics and disinfecting solutions from these different ocular surface conditions. In total, 63 S. aureus strains from the USA and Australia were evaluated; 14 were from niCIE, 26 from conjunctivitis, and 23 from microbial keratitis (MK). The minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) of all the strains to ciprofloxacin, ceftazidime, oxacillin, gentamicin, vancomycin, chloramphenicol, azithromycin, and polymyxin B were determined. The MIC and MBC of the niCIE strains to contact lens multipurpose disinfectant solutions (MPDSs) was determined. All isolates were susceptible to vancomycin (100%). The susceptibility to other antibiotics decreased in the following order: gentamicin (98%), chloramphenicol (76%), oxacillin (74%), ciprofloxacin (46%), ceftazidime (11%), azithromycin (8%), and polymyxin B (8%). In total, 87% of all the isolates were multidrug resistant and 17% of the isolates from microbial keratitis were extensively drug resistant. The microbial keratitis strains from Australia were usually susceptible to ciprofloxacin (57% vs. 11%; p = 0.04) and oxacillin (93% vs. 11%; p = 0.02) compared to microbial keratitis isolates from the USA. Microbial keratitis isolates from the USA were less susceptible (55%) to chloramphenicol compared to conjunctivitis strains (95%; p = 0.01). Similarly, 75% of conjunctivitis strains from Australia were susceptible to chloramphenicol compared to 14% of microbial keratitis strains (p = 0.04). Most (93%) strains isolated from contact lens wearers were killed in 100% MPDS, except S. aureus 27. OPTI-FREE PureMoist was the most active MPDS against all strains with 35% of strains having an MIC ≤ 11.36%. There was a significant difference in susceptibility between OPTI-FREE PureMoist and Biotrue (p = 0.02). S. aureus non-infectious CIE strains were more susceptible to antibiotics than conjunctivitis strains and conjunctivitis strains were more susceptible than microbial keratitis strains. Microbial keratitis strains from Australia (isolated between 2006 and 2018) were more susceptible to antibiotics in comparison with microbial keratitis strains from the USA (isolated in 2004). Most of the strains were multidrug-resistant. There was variability in the susceptibility of contact lens isolates to MPDSs with one S. aureus strain, S. aureus 27, isolated from niCIE, in Australia in 1997 being highly resistant to all four MPDSs and three different types of antibiotics. Knowledge of the rates of resistance to antibiotics in different conditions and regions could help guide treatment of these diseases.

Alternative Therapeutic Interventions: Antimicrobial Peptides and Small Molecules to Treat Microbial Keratitis

Microbial keratitis is a leading cause of blindness worldwide and results in unilateral vision loss in an estimated 2 million people per year. Bacteria and fungus are two main etiological agents that cause corneal ulcers. Although antibiotics and antifungals are commonly used to treat corneal infections, a clear trend with increasing resistance to these antimicrobials is emerging at rapid pace. Extensive research has been carried out to determine alternative therapeutic interventions, and antimicrobial peptides (AMPs) are increasingly recognized for their clinical potential in treating infections. Small molecules targeted against virulence factors of the pathogens and natural compounds are also explored to meet the challenges and growing demand for therapeutic agents. Here we review the potential of AMPs, small molecules, and natural compounds as alternative therapeutic interventions for the treatment of corneal infections to combat antimicrobial resistance. Additionally, we have also discussed about the different formats of drug delivery systems for optimal administration of drugs to treat microbial keratitis.

Microbial Spectrum and Resistance Patterns in Ocular Infections: A 15-Year Review in East China

Purpose

To report antibiotic resistance rates and trends of common ocular isolates collected over a 15-year period.

Methods

We collected 3533 isolates from July 1, 2005 to July 31, 2020. Antibiotic sensitivity was determined according to the guidelines of the Clinical and Laboratory Standards Institute. Chi-squared (χ²) test was used to analyze changes in antibiotic susceptibility over 15 years.

Results

Among the 3533 isolates, the predominant pathogens were the staphylococcal species. Methicillin resistance was observed in 381 Staphylococcus aureus (S. aureus) isolates (46.4%) and 1888 coagulase-negative staphylococci (CoNS) isolates (61.1%), and methicillin-resistant (MR) isolates had a high probability of concurrent resistance to fluoroquinolones and aminoglycosides. The mean percentage of resistance in staphylococcal isolates did not reach statistical significance across patient age groups (P = 0.87). Methicillin resistance did not increase in the CoNS (P = 0.546) isolates, and resistance to methicillin slightly decreased among S. aureus (P = 0.04) isolates over 15 years. Additional exploratory analysis revealed a small decrease in resistance to tobramycin (P = 0.01) and chloramphenicol (P < 0.001) among the CoNS isolates. All staphylococcal isolates were susceptible to vancomycin.

Conclusion

Staphylococci were the most common microorganisms responsible for causing ocular infections. Antibiotic resistance was high among staphylococci, with nearly half of these isolates were resistant to methicillin and these had a high probability of concurrent resistance among MR staphylococci to other antibiotics. Overall, ocular resistance did not significantly change during the 15-year study period. We conclude that continued surveillance of antibiotic resistance provides critical data to guide antibiotic selection.

Medical History, Clinical Features, Treatment Outcome and Its Predictors Among Infectious Keratitis Patients in Jimma University Medical Center, Southwest Ethiopia: Prospective Observational Study

BACKGROUND

Infectious keratitis is a major global cause of visual impairment and irreversible blindness among the corneal diseases. Its diagnosis and management remain getting challenge. The clinical and visual outcome remains poor in developing countries. The aim of this study was to determine treatment outcome and its predictors among patients with infectious keratitis.

METHODS

Prospective observational study was conducted among adult patients diagnosed with infectious keratitis at the Ophthalmology Department in Jimma University Medical Center from April 1 to September 30, 2019. The primary outcome indicator was response of the ulcer to empirical treatment. Ulcers that did not heal and required surgery had a poor outcome. Variables with a p-value of <0.25 were entered into a multivariate logistic regression model to determine the independent predictors of poor treatment outcome and variables with a p-value of <0.05 were considered statistically significant.

RESULTS

The research involved 131 adult patients. Eighty-seven (66.4%) were males. The mean age was 39.38 (±18.9) years. Eighty-three (63.4%) patients had poor treatment outcome. Mean length of hospital stay was 17.38 (±12.563) days. Poor visual outcome was observed among 71 (54.2%) participants. Evisceration was done for seven (5.3%) patients. Independent predictors of poor treatment outcome include perforation at admission (AOR=6.1, 95%CI: 1.5-25.1), presence of comorbidity (AOR=7.7, 95%CI: 2.16-27.3), poor adherence (AOR=5.3, 95%CI: 1.8-25.9), traditional medicine use (AOR=6.7, 95%CI: 1.8-25.4), ulcer depth >1/3 (AOR=7.6, 95%CI: 2.48-48.23) and farm workers (AOR=3.59, 95%CI: 1.09-11.77). Major complications occurred after admissions were perforation (14.5%), followed by endophthalmitis (7.63%) and corneal opacity (6.87%).

CONCLUSION AND RECOMMENDATION

Our study found high poor treatment outcomes and high poor visual outcomes. Presence of comorbidity, perforation at admission, traditional medicine use, working on a farm, poor adherence, and ulcer depth were the predictors of poor treatment outcome. This high poor outcome requires a nationwide interventional study and urgent intervention that may reach rural communities.

Microbes of the human eye: Microbiome, antimicrobial resistance and biofilm formation

BACKGROUND

The review focuses on the bacteria associated with the human eye using the dual approach of detecting cultivable bacteria and the total microbiome using next generation sequencing. The purpose of this review was to highlight the connection between antimicrobial resistance and biofilm formation in ocular bacteria.

METHODS

Pubmed was used as the source to catalogue culturable bacteria and ocular microbiomes associated with the normal eyes and those with ocular diseases, to ascertain the emergence of anti-microbial resistance with special reference to biofilm formation.

RESULTS

This review highlights the genetic strategies used by microorganisms to evade the lethal effects of anti-microbial agents by tracing the connections between candidate genes and biofilm formation.

CONCLUSION

The eye has its own microbiome which needs to be extensively studied under different physiological conditions; data on eye microbiomes of people from different ethnicities, geographical regions etc. are also needed to understand how these microbiomes affect ocular health.

Prevalence and Antibiotic Resistance Patterns of Ocular Bacterial Strains Isolated from Pediatric Patients in University Hospital of Campania “Luigi Vanvitelli,” Naples, Italy

Eye infections caused by bacteria are a serious public health problem among pediatric patients. These diseases, if not properly treated, can cause blindness and impaired vision. The study aimed to evaluate the antimicrobial resistance profiles of the main pathogens involved in eye infections. This study involved pediatric patients enrolled at the “Luigi Vanvitelli” University Hospital of Campania in Naples, Italy, between 2017 and 2019. Of a total of 228 pediatric patients, 73 (32%) tested positive for bacterial infection. In terms of strain distribution, 85% were Gram-positive bacteria, while 15% were Gram-negative bacteria. The most frequently isolated strains were coagulase-negative Staphylococci (60.4%), followed by Staphylococcus aureus (16.4%). The isolated bacteria showed a significant percentage of resistance to multiple antibiotics. Therefore, the identification of the causal bacteria and antimicrobial sensitivity tests are mandatory to select the effective drug for the treatment of eye infections and prevent the development of antibiotic-resistant bacteria.

Management of Endophthalmitis with and without Topical Antibiotics: A Case-Control Study

PURPOSE

The aim of this study was to compare the management outcome of endophthalmitis with and without the use of topical antibiotics.

METHODS

A retrospective comparative chart review of 2 cohorts of endophthalmitis (other than those associated with open-globe injury, keratitis, or wound site infection), one managed with topical antibiotics (TA group) and one without (NTA group), was performed.

RESULTS

The study included a total of 270 eyes of 270 patients. Of these, 169 eyes were in the TA group and 101 were in the NTA group. Post-cataract surgery was the most common etiology, accounting for 81.06 and 78.2% of cases, respectively (p = 0.57). A favorable functional outcome at the last visit was seen in 37.5 and 39.6% of eyes (p = 0.73), and a favorable anatomic outcome was noted in 61.2 and 49.5% of eyes (p = 0.06), respectively. The median follow-up was 3.5 and 9 months, respectively (p < 0.0001). Susceptibilities to the common antibiotics used (vancomycin, ceftazidime, and amikacin) were comparable, with the exception of imipenem, for which the susceptibility noted was 95 and 66%, respectively (p = 0.01). Culture positivity in the TA group was seen in 72 out of 169 eyes (42.6%), while in the NTA group it was seen in 98 out of 101 eyes (97.02%; p < 0.0001).

CONCLUSION

Topical antibiotics do not give any added advantage in the management of endophthalmitis otherwise being treated with intravitreal antibiotics and standard vitrectomy techniques.

In Vitro Biofilm Formation and Antibiotic Susceptibility Patterns of Bacteria from Suspected External Eye Infected Patients Attending Ophthalmology Clinic, Southwest Ethiopia

Background

Ocular disease with its complications is a major public health problem which has significant impacts on the quality of life particularly in developing countries. An eye infection due to bacterial agents can lead to reduced vision and blindness. This study was aimed to assess the antimicrobial susceptibility pattern and biofilm-forming potential of bacteria isolated from suspected external eye infected patients in Jimma.

Method

A cross-sectional facility-based study was conducted on 319 suspect patients with external eye infections from March to June 2017 at Jimma University Medical Center (JUMC) Ophthalmology Department in Ethiopia. External ocular specimens were collected and standard operating procedures were followed to handle and culture throughout the study period. Antimicrobial susceptibility was determined by the disk diffusion method according to CLSI guidelines. Microtiter (96 wells) plate method was used to screen biofilm formation by ELISA reader at 570 nm.

Results

Out of 319 study participants with an external eye infection, the prevalence of bacterial pathogens was 46.1%. The predominant bacterial isolates were coagulase-negative staphylococcus (CoNS) (27.7%) followed by Staphylococcus aureus (19.7%). Among Gram-negative groups, Pseudomonas aeruginosa (6.8%) was the leading isolate. Increased antimicrobial resistance was observed for tetracycline (64%), erythromycin (66.7%), and penicillin (77.1%). Amoxicillin-clavulanic acid, ciprofloxacin, and gentamicin were the most effective drugs for external eye infections due to susceptibility ranging from 70 to 100% among both Gram-negative and Gram-positive groups. Methicillin-resistant S. aureus (MRSA) accounted for 13.8%. Multidrug resistance (MDR) accounted for 68.7%. The overall biofilm formation rate of bacterial ocular pathogens was 66.1%, where P. aeruginosa (40%), CoNS (34.1%), and S. aureus (31%) formed strong biofilm phenotype.

Conclusion

The prevalence rate of bacterial isolates was high. Almost all bacterial isolates were resistant to at least one or more drugs. MDR pathogens were observed increasingly among biofilm formers or vice versa.

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 among bacterial conjunctival pathogens collected in the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study

The Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study evaluates in vitro antibiotic resistance among Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae isolates from ocular infections. Here we report resistance rates and trends among conjunctival-sourced ocular isolates collected across the US from 2009 through 2016. A total of 1198 conjunctival isolates (483 S. aureus, 305 CoNS, 208 H. influenzae, 118 S. pneumoniae, and 84 P. aeruginosa) were collected from patients with presumed bacterial conjunctivitis from 57 sites across 40 states. A large proportion of staphylococci demonstrated resistance to oxacillin and azithromycin, while resistance was low against the majority of antibiotics tested for S. pneumoniae, P. aeruginosa, and H. influenzae. Multidrug resistance (≥3 antibiotic classes) was found in 30.2% of S. aureus and 39.0% of CoNS isolates, and methicillin resistance more than doubled the rate of multi-drug resistance (methicillin-resistant S. aureus [MRSA], 76.5%; methicillin-resistant CoNS isolates, 72.8%). There was a pattern of increasing mean percent resistance with increasing age by decade of life among S. aureus, MRSA, and CoNS (P≤0.038). Over the eight-year study period, there were small yet significant decreases in resistance rates among S. aureus to azithromycin, ciprofloxacin, tobramycin, trimethoprim, and oxacillin (P≤0.003), and among CoNS and P. aeruginosa (both P<0.05) to ciprofloxacin. These data indicate that antibiotic resistance is high, but did not increase, among conjunctival-sourced isolates collected in the US from 2009 through 2016. For certain antibiotic/pathogen combinations, there was a trend of decreased resistance, including a decrease in oxacillin resistance among S. aureus.

Ocular bacterial infections and antibiotic resistance patterns in patients attending Gondar Teaching Hospital, Northwest Ethiopia

Objectives

Empirical selections of antimicrobial therapy based on clinical observations are common clinical practices in Ethiopia. This study identified common external ocular infections and determined antibiotic susceptibility testing in northwest Ethiopia.

Results

Among 210 patients studied, conjunctivitis 32.9%(69), blepharitis 26.7%(56), dacryocystitis 14.8%(51), blepharoconjunctivitis 11.9%(25), and trauma 10.0%(21) were the most common external ocular infections. Pathogenic bacteria were isolated among 62.4%(131) cases. The distributions of bacteria detected in conjunctivitis, dacryocystitis, and blepharitis patients were 32.8%(43), 23.7%(31), and 16.0%(21), respectively. The most prevalent isolates were coagulase negative Staphylococci; 27.5%(36), S. aureus; 26.7%(35), Pseudomonas species; 10.7%(14), and E. coli; 7.6%(10). Tetracycline, amoxicillin, chloramphenicol, ampicillin, and nalidic acid showed resistance to bacterial isolates with a respective prevalence of 35.9%(47), 32.1%(42), 26.2%(34), 25.2%(33), and 23.7%(31). Multi-drug resistance patterns to the commonly prescribed antibiotics tested was 20.6%(27), 18.3%(24), 17.6%(23), 5.3%(7), and 4.6%(6) to two, three, four, five, and six antibiotics, respectively. Overall, the multi-drug resistance prevalence rate was 66.4%(87). This study confirmed diverse types of external ocular manifestations associated with bacterial infections with wide ranges of antibiotic resistant phenotypes. Thus, combining clinical information, bacteriological analysis, and antimicrobial susceptibility tests are useful for making an evidence-based selection of antibiotics therapy.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3705-y) contains supplementary material, which is available to authorized users.

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.

Ophthalmic Drug Delivery Systems for Antibiotherapy-A Review

The last fifty years, ophthalmic drug delivery research has made much progress, challenging scientists about the advantages and limitations of this drug delivery approach. Topical eye drops are the most commonly used formulation in ocular drug delivery. Despite the good tolerance for patients, this topical administration is only focus on the anterior ocular diseases and had a high precorneal loss of drugs due to the tears production and ocular barriers. Antibiotics are popularly used in solution or in ointment for the ophthalmic route. However, their local bioavailability needs to be improved in order to decrease the frequency of administrations and the side effects and to increase their therapeutic efficiency. For this purpose, sustained release forms for ophthalmic delivery of antibiotics were developed. This review briefly describes the ocular administration with the ocular barriers and the currently topical forms. It focuses on experimental results to bypass the limitations of ocular antibiotic delivery with new ocular technology as colloidal and in situ gelling systems or with the improvement of existing forms as implants and contact lenses. Nanotechnology is presently a promising drug delivery way to provide protection of antibiotics and improve pathway through ocular barriers and deliver drugs to specific target sites.

Bacterial Contamination of Multi-dose Eye Drops at Ophthalmology Department, University of Gondar, Northwest Ethiopia

PURPOSE:

Ophthalmic solutions used for both diagnostic and therapeutic purposes were found to be contaminated with bacteria pathogens and caused serious ocular infections such as keratitis and endophthalmitis. The objective was to assess the magnitude and pattern of bacterial contamination of multi-dose ophthalmic medications and investigate the drug susceptibility pattern of the isolates in the Department of Ophthalmology at Gondar University Teaching Hospital.

METHODS:

A total of 100 ophthalmic medications in-use by patients and eye-care workers have been taken and cultured for potential bacterial contamination in the Microbiology Department after 1 week and >1 week of use. The dropper tip and the residual eye medications were examined for contamination. The contaminating bacteria were identified using a standard procedure and drug susceptibility testing to selected antimicrobial agents was done.

RESULTS:

Eleven ophthalmic medications were contaminated by different bacterial species with a prevalence of 11%. Multi-use and longer duration of use of eye medications were associated with higher rate of contamination. The contamination level ranges from 0% for antibiotics, 20% for local anesthetics, and 40% for povidone iodine. Among bacteria identified, Staphylococcus aureus and coagulase-negative Staphylococcus species were resistant to methicillin while others were sensitive to the antibiotics tested.

CONCLUSION:

The prevalence of contamination was low, but methicillin-resistant Staphylococcus was a potential risk. It is recommended that the Department of Ophthalmology should design set of rules about duration of use and safe handling of ophthalmic medications by the staff and patients.

Bacterial pathogens associated with external ocular infections alongside eminent proportion of multidrug resistant isolates at the University of Gondar Hospital, northwest Ethiopia

BACKGROUND

External ocular infection is a public health problem in Ethiopia. The aim of this study was to determine the prevalence and antimicrobial susceptibility pattern of external ocular bacterial infections.

METHODS

A cross sectional study was conducted at the University of Gondar Hospital among patients seeking health services at the Department of Ophthalmology from January to April, 2016. All patients with suspected external ocular infections were examined under slit lamp microscope. External ocular samples were collected using aseptic techniques. All samples were investigated by culture and bacteria were identified using standard methods. Drug susceptibility test was done using the Kirby-Bauer Disk diffusion method according to the guidelines of Clinical and Laboratory Standard Institute (CLSI).

RESULT

A total of 312 samples were collected and 58.3% were culture positive. The proportion of Gram positive bacterial pathogens was (88%), and Staphylococcus aureus (50.3%) was the predominantly isolated pathogen, followed by Coagulase negative staphylococci (CoNS) (33.5%) and Klebsiella species (4.7%). Conjunctivitis was the dominant clinical feature, but a high positive result for bacterial pathogens was observed among patients with dacryocystitis cases. The Gram positive bacterial isolates were susceptible to ciprofloxacin, chloramphinicol, amoxicillin-clavulanate and ceftriaxone. However, 65% of these Gram positive bacterial pathogens showed resistance to penicillin, ampicillin and amoxicillin. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection was 24% and multidrug resistance (MDR) was observed in 87% of the isolated bacteria.

CONCLUSION

Conjunctivitis was the dominant ophthalmic disease followed by blepharitis. The dominant bacteria species was S. aureus and MRSA infection is increasingly prevalent. The overall MDR bacterial pathogen proportion was very high. The high prevalence of MRSA and MDR bacterial pathogens dictate the need for effective prevention as important as for therapies.

Prevalence and antibacterial resistance patterns of extended-spectrum beta-lactamase producing Gram-negative bacteria isolated from ocular infections

Purpose:

Extended-spectrum beta-lactamases (ESBLs) mediated resistance is more prevalent worldwide, especially among Gram-negative bacterial isolates, conferring resistance to the expanded spectrum cephalosporins. As limited data were available on the prevalence of ESBLs in this area, the current study was undertaken to determine the prevalence, antibacterial resistance patterns, and molecular detection and characterization of ESBL encoding resistance genes among ocular Gram-negative bacterial isolates from ocular infections.

Materials and Methods:

A prospective study was done on 252 ocular Gram-negative bacterial isolates recovered from ocular infections during a study period from February 2011 to January 2014. All isolates were subjected to detection of ESBLs by cephalosporin/clavulanate combination disc test and their antibacterial resistance pattern was studied. Molecular detection and characterization of ESBL encoding bla_TEM-, bla_SHV, bla_OXA-, and bla_CTX-M (phylogenetic groups 1, 2, 9, and 8/25) resistance genes by multiplex polymerase chain reaction and DNA sequence analysis.

Results:

Of all Gram-negative bacteria, Pseudomonas aeruginosa (44%) was the most common strain, followed by Enterobacter agglomerans and Klebsiella pneumoniae each (10%). Among the 252, 42 (17%) were ESBL producers. The major source of ESBL producers were corneal scraping specimens, highest ESBL production was observed in P. aeruginosa 16 (38%) and Escherichia coli 7 (16.6%). Among ESBL-producing genes, the prevalence of bla_TEM-gene was the highest (83%) followed by bla_OXA-gene (35%), bla_SHV-gene (18.5%), and bla_CTX-M-1-gene (18.5%) alone or together.

Conclusion:

The higher rate of prevalence of ESBLs-encoding genes among ocular Gram-negative bacteria is of great concern, as it causes limitation to therapeutic options. This regional knowledge will help in guiding appropriate antibiotic use which is highly warranted.

Update on the Epidemiology and Antibiotic Resistance of Ocular Infections

PURPOSE:

The purpose of this review is to provide an update on the epidemiology and current antibiotic-resistant threats in ophthalmology.

METHODS:

Trends in frequency and antibiotic-nonsusceptible profiles during an 11 year-period (2005–2015) were evaluated and compared with the 5-year Antibiotic Resistance Monitoring in Ocular Microorganism (ARMOR) study.

RESULTS:

Trends in the current review confirmed the continued high rates of fluoroquinolone nonsusceptbility circulating among ocular methicillin-susceptible Staphylococcus aureus, methicillin-susceptible Staphylococcus epidermidis, methicillin-resistant S. aureus, and methicillin-resistant S. epidermidis isolates as well as the detection of uncommon, but emerging resistance (<5%) for Streptococcus pneumoniae, Streptococcus viridans group, Haemophilus influenzae, and Pseudomonas aeruginosa. We documented significant differences in empirical fluoroquinolone and aminoglycoside coverage for the top three ocular pathogens (coagulase-negative staphylococci, S. aureus, and P. aeruginosa) in general and for corneal isolates between the Miami and the ARMOR studies. Collectively, the coverage for Miami was 74% versus 65.9% for ARMOR (P < 0.0001, 5.3674–10.8042) for ciprofloxacin and 95.9% versus 84.2% for aminoglycosides (gentamicin/tobramycin) (P < 0.0001, 9.9925–13.3974). Monotherapy coverage for ciprofloxacin and levofloxacin for the most recent 5 years (2011–2015) was 76.6% and 77.1%, respectively. Combination therapy with a fluoroquinolone and vancomycin and/or vancomycin and an aminoglycoside provided coverage for 99% and 98% of the isolates, respectively.

CONCLUSION:

The etiology of ocular pathogens is patient, source, and geography specific. The true incidence and/or prevalence are unknown. Fluoroquinolone monotherapy as standard therapy for common ocular infections needs to be reassessed. Ophthalmologists must become proactive and join the crusade to develop practical and prudent strategies for the administration of topical antibiotics.

Retrospective report of antimicrobial susceptibility observed in bacterial pathogens isolated from ocular samples at Mount Sinai Hospital, 2010 to 2015

BACKGROUND

Antimicrobial resistance has emerged as a major threat to global public health. Thus, the surveillance of changes in antimicrobial resistance in local and global settings is a paramount necessity. While many studies have tracked antimicrobial resistance, only a small percentage surveyed ocular isolates. The purpose of this study was to report the in vitro susceptibility of bacterial pathogens isolated from ocular samples in New York, NY from 2010 to 2015.

METHODS

A retrospective review of ocular isolates was conducted. All organisms were collected by 25 separate inpatient wards and outpatient clinics, and were analyzed by the clinical microbiology laboratory at Mount Sinai Hospital. Clinical Laboratory and Standards Institute (CLSI) guidelines were followed for susceptibility testing and breakpoint interpretations.

RESULTS

A total of 549 bacterial organisms were isolated from 1664 cultures (33%) during the 6-year study period. Of these, 358 isolates (65.2%) underwent susceptibility testing. 182 (50.8%) isolates were Gram-positive. The most common Gram-positive bacterium was Staphylococcus aureus (62.1%). Methicillin-resistance decreased in S. aureus isolates (31.3% in 2010, 14.1% in 2015) but was without significant change (p = 0.25). When analyzing all S. aureus isolates recovered during the study period, there were significantly more methicillin-resistant S. aureus (MRSA) isolates resistant to fluoroquinolones (p <0.0001), erythromycin (p <0.0001), and trimethoprim/sulfamethoxazole (TMP/SMZ; p <0.05). Overall, Streptococcus pneumoniae isolates showed reduced susceptibility to erythromycin, but were otherwise susceptible to the other antimicrobials tested. Haemophilus influenzae (26.1%) and Pseudomonas aeruginosa (23.9%) were the most common Gram-negative bacteria isolated. Resistance to ampicillin and TMP/SMZ was observed in several of the H. influenzae isolates. P. aeruginosa isolates did not show high resistance overall, however, it was noted that isolates resistant to meropenem were also resistant to other antimicrobials (p < 0.01).

CONCLUSION

Overall, antimicrobial resistance was infrequent for the Gram-negative and Gram-positive bacteria analyzed. While the MRSA isolates demonstrated increased resistance to multiple antimicrobial classes, this is expected for this pathogen. Due to the continued use of broad-spectrum oral and systemic antimicrobials to treat ocular infections, findings of this study and other surveillance studies specific to ocular isolates should be used as resources in effective decision making in the treatment of ocular disease.

Ocular bacterial infections at Quiha Ophthalmic Hospital, Northern Ethiopia: an evaluation according to the risk factors and the antimicrobial susceptibility of bacterial isolates

BACKGROUND

External and intraocular infections can lead to visual impairments, which is a major public health problem. Bacteria are the most frequent pathogens affecting ocular structures; the increasing rate of antimicrobial drug resistance is a worldwide concern. The aim of this study was to determine the occurrence of bacteria in ocular infections, their antimicrobial susceptibility patterns, and risk factors in bacterial ocular infection.

METHODS

A hospital based cross-sectional study was conducted from September 2015 to December 2015 at Quiha Ophthalmic Hospital, Tigray, northern Ethiopia. Ocular specimens from blepharitis, blepharoconjunctivitis, conjunctivitis, keratitis, endophthalmitis, periorbital cellulitis and dacrocystitis were collected from 270 individuals with suspected ocular infection. Data on sociodemographic and risk factors were also collected using a structured questionnaire. Data analysis was performed using SPSS version 21 and 0.05 with a corresponding 95% confidence interval (CI) was considered statistically significant.

RESULTS

Among 270 study subjects, 180 (66.7%) were culture positive for different bacterial isolates. The predominant bacterial isolates were Staphylococcus aureus (40, 22.2%), coagulase negative staphylococci (31, 17.2%) and Pseudomonas aeruginosa (21, 11.7%). Ocular surface disease, ocular trauma, hospitalization and cosmetic application practices were significantly associated with the occurrence of bacterial infection. Concerning antimicrobial susceptibility, most isolates were susceptible to amikacin (137, 93.2%), gentamicin (131, 89.1%) and ciprofloxacin (141, 89.2%). Overall, 40 (22.5%), 34 (19.1%) and 62 (34.8%) isolates were resistant to one, two, and three or more antimicrobials, respectively.

CONCLUSION

Bacteria were isolated from the majority of the study subjects. More than half of the bacterial isolates were resistant at least to one drug and a significant rate of multidrug resistance was detected. Therefore, identification of the etiologic agent and antimicrobial susceptibility testing should be practiced to select the appropriate antimicrobial agent to treat eye infections and prevent the emergence of drug resistant bacteria.

Bacterial isolates and their antimicrobial susceptibility pattern among patients with external ocular infections at Borumeda hospital, Northeast Ethiopia

Background

Bacteria are major cause of ocular infections and possible loss of vision. The emergence of antimicrobial resistant bacteria increases the risk of treatment failure with potentially serious consequences. The aim of this study was to determine the prevalence of bacterial isolates and their antimicrobial susceptibility pattern among patients with external ocular infections.

Methods

A cross sectional study was conducted among 160 patients with external ocular infections at Borumeda hospital, Northeast Ethiopia. Socio-demographic and clinical data were collected using structured questionnaire. External ocular specimens were collected using sterile swabs and inoculated on MacConkey agar, Chocolate agar and Blood agar culture Medias. Presumptive isolates were further identified by a series of biochemical tests. The antimicrobial susceptibility patterns of the isolates were determined by disk diffusion method.

Result

The overall prevalence of bacterial pathogens among external ocular samples was 59.4 %. The majority of the isolates (93.7 %; 89/95) were Gram positive and the other 6.3 % (6/95) Gram negative bacteria. The proportion of coagulase negative Staphylococci among the Gram positive bacterial isolates was 53.7 % (n = 51/95). All Gram positive isolates were susceptible for vancomycin but 67.4 % (n = 60/95) of them were resistant against amoxicillin. Moreover, drug resistance to tetracycline, norfloxacylin, ceftriaxone and ciprofloxacin were observed among Gram negative bacteria isolates.

Conclusion

The prevalence of bacterial pathogens among external ocular samples was high and the predominant isolate was coagulase negative Staphylococci. Exceptionally high amoxicillin resistance was observed among Gram positive bacterial isolates that may dictate to conduct drug susceptibility test routinely.

Contact lenses as drug reservoirs & delivery systems: the successes & challenges

Although conventional eye drops comprise over 90% of the marketed ocular dosage forms, they do have limitations, such as poor ocular drug bioavailability and systemic side effects; contact lenses are amongst the new delivery systems and devices that could overcome some of these problems. The most common approach to load drug molecules into contact lenses includes soaking in a drug solution. This approach had some success, but failed to achieve controlled/sustained drug release to the eye. On the other hand, nanoreservoir systems comprising nanoparticles, cyclodextrins, liposomes or surfactant aggregates being incorporated into the contact lenses could offer a plausible solution. This review highlights the status quo with contact lenses as ocular drug-delivery carriers and identifies possible future directions.

Defensin production by human limbo-corneal fibroblasts infected with mycobacteria

Epithelial cells of the cornea and the conjunctiva constitutively produce antimicrobial peptides; however, the production of defensins by other cell types located around the eye has not been investigated. We analyzed the production of beta-defensins (hBD) and cathelicidin LL-37 during the infection of primary limbo-corneal fibroblasts with M. tuberculosis (MTB), M. abscessus (MAB), and M. smegmatis (MSM). The intracellular survival of each mycobacterium, the production of cytokines and the changes on the distribution of the actin filaments during the infection were also analyzed. Fibroblasts produce basal levels of hBD1 and LL-37 and under PMA stimulation they produce hBD2, hBD3 and overexpress hBD1 and LL-37. MAB induced the highest levels of hBD1 and LL-37 and intermediate levels of IL-6; however, MAB was not eliminated. In addition, MAB induced the greatest change to the distribution of the actin filaments. MTB also produced changes in the structure of the cytoskeleton and induced low levels of hBD1 and IL-6, and intermediate levels of LL-37. The balance of these molecules induced by MTB appeared to contribute to the non-replicative state observed in the limbo-corneal cells. MSM induced the lowest levels of hBD1 and LL-37 but the highest levels of IL-6; MSM was eliminated. The results suggest that mycobacterial infections regulate the production of antimicrobial peptides and cytokines, which in conjunction can contribute to the control of the bacilli.

Besifloxacin ophthalmic suspension 0.6% administered twice daily for 3 days in the treatment of bacterial conjunctivitis in adults and children

BACKGROUND AND OBJECTIVE

Besifloxacin ophthalmic suspension 0.6% given thrice daily for 5 days is safe and effective in the treatment of patients with bacterial conjunctivitis. This study evaluated the safety and efficacy of besifloxacin ophthalmic suspension 0.6% administered twice daily for 3 days compared with vehicle in the treatment of bacterial conjunctivitis.

STUDY DESIGN

This was a multicenter, double-masked, randomized, vehicle-controlled, parallel-group study.

METHODS

A total of 474 patients aged ≥1 year with bacterial conjunctivitis were randomized in a 1 : 1 ratio to receive either besifloxacin ophthalmic suspension 0.6% or vehicle administered twice daily for 3 days. There were three study visits: day 1 (the baseline visit), day 4/5 (visit 2), and day 7 ± 1 (visit 3). The co-primary efficacy endpoints were bacterial eradication and clinical resolution at day 4/5 in designated study eyes of patients with culture-confirmed bacterial conjunctivitis. Secondary efficacy endpoints were bacterial eradication and clinical resolution at day 7 ± 1, individual clinical outcomes of ocular discharge and bulbar conjunctival injection at all visits; and microbial and clinical outcomes for overall bacterial species and individual Gram-positive and Gram-negative bacterial species at each follow-up visit. Safety endpoints included adverse events (AEs), changes in visual acuity and biomicroscopy findings at each visit, and changes in ophthalmoscopy findings at day 7 ± 1.

RESULTS

Bacterial eradication and clinical resolution rates were significantly higher in the besifloxacin group than in the vehicle group (115/135 [85.2%] vs 77/141 [54.6%], p < 0.001, and 89/135 [65.9%] vs 62/141 [44.0%], p < 0.001, respectively) at day 4/5. Rates of bacterial eradication continued to be significantly greater in the besifloxacin group (115/135 [85.2%] vs 91/141 [64.5%], respectively; p < 0.001) at day 7 ± 1; however, the rates of clinical resolution did not differ significantly between the groups (103/135 [76.3%] and 94/141 [66.7%], p = 0.209) at this visit. Ocular discharge and bulbar conjunctival injection at each visit were consistent with the primary outcomes. Clinical resolution and bacterial eradication with Gram-positive or Gram-negative organisms were consistent with the overall findings. All AEs in both groups were of mild or moderate severity and were considered unrelated to the treatment.

CONCLUSION

Treatment with besifloxacin ophthalmic suspension 0.6% administered twice daily for 3 days was effective and safe in adults and children with bacterial conjunctivitis.

CLINICAL TRIAL REGISTRATION

Registered at ClinicalTrials.gov as NCT00972777.