Research advances in contact lens associated bacterial keratitis / 国际眼科杂志(Guoji Yanke Zazhi)

Contact lens(CL)is currently one of the most common methods of vision correction, with more than 140 million users worldwide and the demand is rising yearly as constantly development of materials and features. Wearing CL can lead to a variety of complications such as dry eye, corneal abrasions, giant papillary conjunctivitis, and infectious keratitis is one of the most severe complications. According to research, bacteria account for 80%～95% of the pathogens that cause CL-associated infective keratitis, it may have been related to the bacterial composition, virulence mechanism, biofilm formation and the combined effect of the lens itself and the process of use, which is prone to introducing pathogens, reducing antimicrobial capacity of the cornea and tears and causing ocular surface hypoxia and ocular surface inflammation. Overnight and prolonged lens wear, irregular lens purchase, use and care procedures can also be risk factors for bacterial infections. This article reviews the studies on the pathogenesis, risk factors, diagnosis, treatment and prevention of CL-related bacterial keratitis.

Antibiotic susceptibility pattern of bacterial isolates from microbial keratitis in North and Central India: A multi centric study

Purpose: This study was conducted to examine microbiological profile with their antibiotic sensitivity in cases of bacterial keratitis in north and central India to ensure appropriate use of antibiotics. Methods: The microbiology laboratory records of 228 patients with culture?proven bacterial keratitis from 1st January to 31st December 2019 were analyzed. Cultured bacterial isolates were subjected to antimicrobial susceptibility testing to antibiotics commonly used in the treatment of corneal ulcer. Chi?squared or Fisher’s exact test were applied to check the significance of difference between the susceptibility levels of antibiotics. Results: The prevalence of Staphylococcus aureus and Pseudomonas aeruginosa–induced keratitis was higher in northern India, whereas that by Streptococcus pneumoniae was more prevalent in central India. In central India, 100% of S. pneumoniae isolates were found to be sensitive to ceftriaxone compared to 79% in northern India (P = 0.017). In comparison to 67% of isolates from north India, 15% of S. aureus isolates from central India were found to be sensitive to ofloxacin (P = 0.009). Similarly, 23% of isolates from central India were found sensitive to amikacin compared to 65% of isolates from north India (P = 0.012). P. aeruginosa isolates from central India were found to be sensitive to ceftazidime in 63% of cases compared to 21% of isolates from north India (P = 0.034). Conclusion: Prevalence of bacteria and their susceptibility to antibiotics are not uniform across geography. Vancomycin remained the most effective drug in all gram?positive coccal infections. S. aureus susceptibility to amikacin was significantly greater in north India. P. aeruginosa showed less susceptibility as compared to previous reports.

Spectrum of bacterial keratitis in North India: A retrospective analysis of six years at a tertiary care eye center

Purpose: To analyze the pattern of bacterial pathogens causing infective keratitis and their resistance to the recommended antibiotics over six years. Methods: It was a retrospective study of 9,357 cases of bacterial keratitis from January 2015 to December 2020, at a tertiary care ophthalmic center. A total of 9,547 corneal specimens were obtained from the study subjects. Demographic details of the patients, pathogenic bacteria isolated, and their antimicrobial susceptibility were noted and analyzed. Results: Bacterial pathogens were identified in 23.52% of the specimens. The most common isolates were coagulase?negative Staphylococci (60.75%), followed by Pseudomonas aeruginosa (14.23%), Staphylococcus aureus (13.92%), gram negative bacilli of the family Enterobacterales (8.64%), Streptococcus spp. (1.72%), Acinetobacter spp. (0.13%), and other non?fermenting gram?negative bacilli (0.57%). In Staphylococci, 55–80% of isolates were resistant to erythromycin, and 40–70% to fluoroquinolones, while no resistance was observed against vancomycin. 40–60% of isolates of P. aeruginosa were resistant to cephalosporins, 40–55% to fluoroquinolones, and 30–60% to aminoglycosides. Also, 40–80% of isolates of Enterobacterales were resistant to cephalosporins, and 50–60% to fluoroquinolones. Most gram?negative isolates were susceptible to carbapenems and polymyxin B. Conclusion: To the best of our knowledge, our study is the largest compilation of microbiological profile of bacterial keratitis from North India. It highlights the current trend of the bacterial pathogens that cause infectious keratitis. Staphylococci and Pseudomonas were found to be the most common pathogens. Increased resistance was seen against some of the commonly prescribed empirical antibiotics. Such evidence is useful for restructuring the empirical prescription practices from time to time.

Comparative study on costs incurred for treatment of patients with bacterial and fungal keratitis - A retrospective analysis

Purpose: To compare the costs associated with medications and travel of patients with smear?proven bacterial keratitis and fungal keratitis in a tertiary care center in India. Methods: Retrospective analysis of case records of a cohort of patients who presented between April 2017 and March 2018 to a tertiary care center in India, with infectious keratitis who were smear?positive for bacteria or fungi, and whose costs of treatment and travel were supported by a philanthropic program. Results: In total, 672 case records of 177 smear?positive bacterial keratitis (BK) and 495 smear?positive fungal keratitis (FK) were included in the study. Further, 62% of BK and 75% of FK received more than one antimicrobial drug (P < 0.001). The mean total medication cost (INR) was significantly more in FK (959.1 � 675.2) compared to BK (674.9 � 463.7) (P < 0.0001). The mean medication cost (INR) per visit was also more for FK (201.1 � 109.4) compared to BK (155.2 � 84.1) (P < 0.0001). The mean total medication cost was significantly more for FK for both patients who healed with medical treatment (611.6 � 395.6 for BK, 801.5 � 599.9 for FK, P = 0.0005) and for patients who required TPK (953.7 � 653.1 for BK, 1374.6 � 701.5 for FK, P = 0.0023) compared to their respective counterparts in BK. Conclusion: Patients with fungal keratitis incurred significantly more on medications compared to patients with bacterial keratitis irrespective of whether they had healed with successful medical treatment or required therapeutic keratoplasty. Prolonged duration of treatment and the high costs of antifungal medications account for the significant economic burden of fungal keratitis.

Analysis of differentially expressed genes in bacterial and fungal keratitis

Purpose: This study was aimed at identifying differentially expressed genes (DEGs) in bacterial and fungal keratitis. The candidate genes can be selected and quantified to distinguish between causative agents of infectious keratitis to improve therapeutic outcomes. Methods: The expression profile of bacterial or fungal infection, and normal corneal tissues were downloaded from the Gene Expression Omnibus. The limma package in R was used to screen DEGs in bacterial and fungal keratitis. The Co-Express tool was used to calculate correlation coefficients of co-expressed genes. The "Advanced network merge" function of Cytoscape tool was applied to obtain a fusional co-expression network based on bacterial and fungal keratitis DEGs. Finally, functional enrichment analysis by DAVID software and KEGG analysis by KOBAS of DEGs in fusion network were performed. Results: In total, 451 DEGs in bacterial keratitis and 353 DEGs in fungal keratitis were screened, among which 148 DEGs were found only in bacterial keratitis and 50 DEGs only in fungal keratitis. Besides, 117 co-expressed gene pairs were identified among bacterial keratitis DEGs and 87 pairs among fungal keratitis DEGs. In total, nine biological pathways and seven KEGG pathways were screened by analyzing DEGs in the fusional co-expression network. Conclusion: TLR4 is the representative DEG specific to bacterial keratitis, and SOD2 is the representative DEG specific to fungal keratitis, both of which are promising candidate genes to distinguish between bacterial and fungal keratitis.

Clinico-microbiological Profile Of Infective Keratitis In A Tertiary Care Hospital, Eastern India

Background: Infective Keratitis (Microbial Keratitis) is infection of the cornea caused by a wide spectrum of micro-bial agents. Its main clinical presentation is Corneal ulcer that is defined as a loss of corneal epithelium. According to World health organization (WHO), corneal diseases are among the major causes of vision loss and blindness in the world today, second only to cataract in overall importance. Aim:To isolate and identify the pathogenic organism Method:The study was conducted in 45 patients diagnosed with corneal ulcer attending Ophthalmology OPD, MKCG Medical College and Hospital, Berhampur over a period of 2 months. The material was scraped from the lead-ing edge and base of the ulcer and was inoculated onto Blood agar, Mac conkey agar and Sabouraud Dextrose agar for culture and onto 2 slides for Gram’s stain and 10% KOH wet mount. The susceptibility testing was done by Kirby Bauer’s disc diffusion method. Results: Out of total 45 patients,35were males. Majority of the patients belonged to age group of 50-60 years. Pain, Redness, Hypopyon was most commonly seen in Bacterial keratitis. In Fungal Keratitis, Redness (80%), Blurred vision (80%) was seen. Most common occupation was Farmers (66.6%). Trauma was the most common risk factor (23 isolates). Majority were bacterial isolates (29 isolates,64.4%) followed by fungal (5 iso-lates ,11.1%). Predominant isolate was Staphylococcus aureus(68.9%). All the gram-positive isolates showed 100%senitivity to Linezolid and Vancomycin. Conclusion: Knowledge of local prevalence of etiological agents of IK and their susceptibility patterns helps in guiding ophthalmologists to select appropriate antibiotic for empirical therapy

Clinical management of bacterial keratitis in the new era / 中华实验眼科杂志

Bacterial keratitis is a common infectious keratitis.Patients often end up with severe vision loss even after the infection is completely eradicated.With the increasing resistance of pathogens to antibiotics,treatment of bacterial keratitis has become increasingly difficult.Facing such an emerging challenge,the present review outlined recent clinical experience in the diagnosis and treatment of bacterial keratitis.In addition to a summary on practice standards in specimen collection,selection of common culture media and antibiotics,a new simple and efficacious antibiotic delivery method is introduced using continuous subpalpebral lavage for the treatment of severe and recalcitrant bacterial keratitis.

Multi‑drug resistant Pseudomonas aeruginosa keratitis and its effective treatment with topical colistimethate.

The purpose was to evaluate the clinical outcome in multi‑drug resistant Pseudomonas aeruginosa (MDR‑PA) bacterial keratitis and report the successful use of an alternative antibiotic, topical colistimethate in some of them. The medical records of 12 culture‑proven MDR‑PA keratitis patients, all exhibiting in vitro resistance by Kirby–Bauer disc diffusion method to ≥ three classes of routinely used topical antibiotics were reviewed. Eight patients were treated with 0.3% ciprofloxacin or ofloxacin, 1 patient with 5% imipenem/cilastatin and 3 patients with 1.6% colistimethate. The outcomes in 8 eyes treated with only fluoroquinolones were evisceration in 4 eyes, therapeutic corneal graft in 1 eye, phthisis bulbi in 1 eye, and no improvement in 2 eyes. The eye treated with imipenem/cilastin required a therapeutic corneal graft. All the three eyes treated with 1.6% colistimethate healed. Colistimethate may prove to be an effective alternative antibiotic in the treatment of MDR‑PA keratitis.

The regulatory role of LiCl in microbial suppurative keratitis / 国际检验医学杂志

Objective To explore the role of LiCl in microbial suppurative keratitis .Methods Western-blot assay was used to detect the efficacy of LiCl .Inflammatory cytokine levels were examined using Real-time PCR .Cell apoptosis was detected by using TUNEL and flow cytometry assays .Results LiCl promoted corneal resistance to PA infection .Real-time PCR data showed that LiCl enhanced IL-10 expression ,but suppressed TNF-expression .TUNEL and flow cytometry data showed that LiCl promoted the apoptosis of infiltrating cells .Conclusion LiCl promoted host resistance against microbial suppurative keratitis ,via regulating in-flammatory cytokine expression and cell apoptosis .

Infectious keratitis – a review.

Infectious keratitis is an important problem in the Indian context, and epidemiological studies suggest a higher prevalence of disease as compared to the developed world. Various aspects of the problem, including the host defence, ocular and systemic risk factors and microbial mechanisms that enhance pathogenesis have been discussed. The clinical and microbiological approach to the infected eye and patient and the relevant tests have been outlined. The major classes of medications that are used the methods of delivery are specified. Finally, the approach to patients with non-responsive keratitis that requires surgical manoeuvres is also highlighted. Clinical experience is important in distinguishing an infective from an inflammatory corneal pathology. The role of an experienced microbiologist is inevitable, for good clinical outcome. Therapeutic keratoplasty has to be done at the right time for better clinical outcomes.

Gram-Negative Bacterial Keratitis: A 15-Year Review of Clinical Aspects

PURPOSE: In this study we investigated pathogenic organisms, antibiotic susceptibility, and clinical characteristics of patients with Gram-negative bacterial keratitis and elucidated risk factors for poor visual outcomes. METHODS: The authors performed a retrospective chart review of 161 eyes (169 isolates) with Gram-negative bacterial keratitis between January 1998 and December 2012 at Yeungnam University Hospital. The study was divided into 5 periods for analysis of the bacteriological profiles and in vitro antibiotic sensitivity. The epidemiological and clinical characteristics were compared according to 3 groups (Pseudomonas species, Enterobacter species, and Serratia marcescens). Additionally, logistic regression analysis was performed to determine the risk factors. RESULTS: The prevalence of Gram-negative organisms increased from 34.7 to 73.2% between the 1st and 5th periods (p < 0.001). Pseudomonas spp. was the most commonly isolated organism (55 eyes, 32.5%) over the total period, followed by Enterobacter spp. (41 eyes, 24.3%) and Serratia marcescens (33 eyes, 19.5%). The effective antibiotics against Gram-negative bacterial pathogens isolated from culture were cefepime (94.5%), levofloxacin (93.4%), ciprofloxacin (93.0%), and amikacin (92.3%). The incidence was higher in the elderly over 60 years of age and in early adulthood patients in their 20s and 30s. The frequent predisposing factors were contact lens wearing and corneal trauma. S. marcescens had the shortest corneal epithelium healing time (p = 0.012) and the most favorable visual outcome after treatment (p = 0.004) compared with the other species. Risk factors for poor visual outcomes included a best corrected visual acuity less than 0.1 at initial evaluation (p < 0.001) and central corneal lesion (p = 0.027). CONCLUSIONS: Gram-negative bacterial keratitis tended to increase and Pseudomonas spp. was the most common isolate. The clinical prognosis was most favorable in S. marcescens. Early diagnosis of Gram-negative bacterial keratitis and appropriate antibiotic selection including cefepime, quinolone, or amikacin are recommended.

Suero autólogo al 50 % en las queratitis bacterianas / 50 % autologous serum in bacterial keratitis

OBJETIVO: evaluar el comportamiento de las queratitis bacterianas con el tratamiento coadyuvante de suero autólogo tópico al 50 %. MÉTODOS: estudio comparativo, longitudinal y prospectivo. La muestra estuvo constituida por 60 pacientes, divididos de forma aleatoria en dos grupos: A) utilizó tratamiento antibiótico convencional y suero autólogo y B)utilizó solo tratamiento antibiótico convencional (cefazolina y amikacina). Los datos almacenados se procesaron utilizando el paquete estadístico SPSS 15. Las variables se expresaron según sus respectivas medidas de resumen y para la comparación de las terapias se aplicaron pruebas de hipótesis, con un nivel de confianza del 95 % y de error inferior al 0,05 %. RESULTADOS: predominaron en los aislamientos microbiológicos Staphylococcus y Pseudomonas; seguidas por los Streptococcus, gonococos y enterobacterias. En cuanto al tiempo de aparición de los signos que favorecen la cicatrización corneal y la respuesta terapéutica, encontramos que con la aplicación tópica del suero autólogo, en casi dos tercios de los pacientes, estos se manifestaron a partir de la segunda semana de tratamiento y se obtuvo una respuesta terapéutica favorable. CONCLUSIONES: el suero autólogo al 50 % resulta ser un complemento terapéutico efectivo en el manejo de las queratitis infecciosas de etiología bacteriana.

OBJECTIVE: to evaluate the behavior of bacterial keratitis with the adjuvant 50% topical autologous serum treatment. METHODS: comparative, longitudinal and prospective study of 60 patients, randomly distributed into two groups. Group A used the conventional antibiotics treatment plus autologous serum and Group B used only conventional antibiotics treatment (cephazolin and amykacin). The collected data were processed by the statistical package SPSS15. The variables were expressed according to their respective summary measures and hypothesis tests were applied to compare the two therapies; a confidence level of 95 % and error level less than 0,05 % were used. RESULTS: in the microbiological isolates, Staphylococcus and Pseudomonas prevailed, followed by Streptococcus, gonococci and Enterobacteriaceae. Regarding the time of onset of the signs that favor corneal healing and the therapeutic response, it was found that with the topical application of the autologous serum, almost two thirds of the patients showed healing signs since the second week of treatment, revealing a favorable therapeutic response. CONCLUSIONS: the 50 % autologous serum proves to be an effective therapeutic complement in the management of the infectious keratitis of bacterial etiology.

Curative Effect of Trace Hormone Combined with Antibacterial Drugs on Bacterial Keratitis / 中国药师

Objective: To discuss the curative effect of trace hormone combined with antibacterial drugs on bacterial keratitis. Methods:Totally 80 cases of patients with bacterial keratitis were selected and divided into the observation group and the control group at random. The patients in the two groups were given medical treatment with sensitive antibiotics, while the patients in the observation group were additionally given trace cortisol. The clinical curative effect and vision recovery time in the two groups after the 3-week treatment were observed, and the occurrence of complications in the 2-month following-up after the medical treatment was compared as well. Results:After the 3-week medical treatment, the clinical effective rate and vision recovery effective rate in the observation group were much higher than those in the control group (P<0. 05). In the 2-month following-up after the medical treatment, the occurrence of complications in the observation group was much lower than that in the control group (P<0. 05). Conclusion:Trace hormone com-bined with antibacterial drugs has favorable curative effect on bacterial keratitis, which can effectively enhance the healing of helcoma, improve the vision recovery and reduce the occurrence of complications.

Clinical and Microbiological Analysis of Gram-Positive Bacterial Keratitis, a 15-Year Review

PURPOSE: To investigate the shifting trends of pathogenic organisms, antibiotic resistance, and clinical characteristics of patients with Gram-positive bacterial keratitis and to elucidate the prognostic factors. METHODS: We performed a retrospective chart review of 152 isolates in 146 eyes with Gram-positive bacterial keratitis between January 1998 and December 2012. The study was divided into 5 periods for analysis of the bacteriological profiles and in vitro antibiotic resistance. The epidemiological and clinical characteristics were compared according to bacterial isolates. Logistic regression analysis was performed to determine the risk factors. RESULTS: Gram-positive bacterial keratitis tended to decrease and significant change in the distribution of isolates was not observed. Commonly isolated organisms were S. epidermidis (48.7%), S. aureus (25.0%), and S. pneumoniae (7.2%) in order of frequency. The resistance to fluoroquinolone tended to increase (p = 0.104) and resistance to gentamicin was significantly decreased (p = 0.01). S. epidermidis had the shortest corneal epithelium healing time (p = 0.035) and the most favorable visual outcome after treatment (p = 0.035) compared with the other species. Risk factors for poor visual outcomes included a best corrected visual acuity less than 0.1 at initial evaluation and an epithelial healing time greater than 10 days. CONCLUSIONS: Gram-positive bacterial keratitis tended to decrease and S. epidermidis was the most common isolate. The clinical prognosis was most favorable in S. epidermidis. The BCVA less than 0.1 at initial evaluation was an important risk factor for poor visual outcome and surgical treatment in Gram-positive bacterial keratitis.

Efeito terapêutico do crosslinking corneal na ceratite infecciosa / Therapeutic effect of corneal crosslinking on infectious keratitis

OBJETIVO: Avaliar o efeito do crosslinking (CXL) no tratamento de ceratite infecciosa, resistente ao tratamento clínico, e investigar a relação com o agente etiológico. MÉTODOS: Foram incluídos 11 pacientes com diagnóstico de ceratite infecciosa de etiologia bacteriana (sete olhos) e fúngica (quatro olhos) na Fundação Altino Ventura (FAV) no período de outubro de 2011 a maio de 2012. Os pacientes incluídos estavam em uso de colírios há pelo menos sete dias e não apresentavam melhora da infecção. Estes foram avaliados antes da realização do CXL e no período pós-operatório até cicatrização da úlcera. Para realização do CXL foram instiladas gotas de riboflavina a 0,1% e dextrano a 20%, a cada cinco minutos em um período de 30 minutos antes do procedimento, e durante a aplicação da luz ultravioleta A (UVA). A córnea foi exposta à UVA com comprimento de onda de 370ηm ± 5ηm e uma irradiância de 3mW/cm2. RESULTADOS: Os pacientes com infecção bacteriana obtiveram cura do processo infeccioso após o CXL e nenhum paciente com ceratite fúngica apresentou cicatrização. Observou-se associação significante (p = 0,003) entre o agente etiológico e a cicatrização. CONCLUSÃO: O CXL mostrou-se eficaz no tratamento da ceratite bacteriana resistente ao tratamento clínico, evitando a realização de transplante tectônico. Em relação à ceratite fúngica, este procedimento não influenciou na melhora do processo infeccioso.

PURPOSE: To evaluate the effect of corneal crosslinking (CXL) in the treatment of infectious keratitis resistant to medical treatment, and investigate the relation with the CXL outcome to the etiologic agent. METHODS: The study included 11 patients who were diagnosed with bacterial (seven eyes) or fungal keratitis (four eyes) at Altino Ventura Foundation from october 2011 to may 2012. All patients were using antibiotic eye drops for at least 7 days and have had no infection improvement. Patients were evaluated prior to CXL and the postoperative period until healing of the keratitis. For CXL, eyes were first instilled with a solution containing 0.1% riboflavin and 20% dextran for 30 min at a 5-minutes interval. Riboflavin-soaked eyes were then irradiated with UVA light (370ηm ± 5ηm) at 3mW/cm2 for 30 minutes. RESULTS: Eyes with bacterial infection exhibited improvement of infectious symptoms after CXL whereas eyes with fungal keratitis showed no improvement. Thus, there was a statistically significant correlation (p = 0.003) between the etiologic agent and the effectiveness of healing. CONCLUSION: CXL was effective in the treatment of bacterial keratitis resistant to clinical treatment, eliminating the need for surgery. However, CXL was not effective in managing fungal keratitis.

Bacterial keratitis in and around Visakhapatnam.

Introduction: Microbial keratitis is a common potentially vision threatening ocular infection caused by bacteria, fungi, viruses or parasites. Bacterial corneal ulceration is an ocular emergency. Hence an understanding of epidemiological features is important in rapid recognition, timely institution of therapy and optimal management. Objectives: To isolate the specific bacterial pathogens and to determine their antibiotic susceptibility pattern. To determine the risk factors and other epidemiological characteristics of infectious keratitis, and the importance of direct microscopy. Methods: Corneal scrapings were collected under strict aseptic conditions from each patient. The scrapings were subjected to direct microscopy (Gram’s stain), culture, and identification by standard microbiological techniques, and antibiotic sensitivity testing was performed by Kirby-Bauer disc diffusion technique. Results & Conclusions: Bacterial isolates were obtained from 41 out of 100 samples. Gram positive isolates accounted for 56.09% of the isolates, and Gram negative isolates 43.90%. Pseudomonas aeruginosa was the predominant bacterial isolate (26.82%), followed by Streptococcus pneumoniae (19.51%). Corneal ulcers showed a higher prevalence in the 21-50yr age group (58.53%), with agricultural labourers contributing to 51.21%. Peak incidence of corneal ulceration was seen during the monsoon season (June – September). History of trauma to the eye, with vegetative matter, was the most frequent predisposing factor noted, representing to 65.85% of the cases. Both Gram negative and Gram positive isolates were more commonly sensitive to amikacin and gentamicin. Both smear & culture positivity was noted in 35 out of 41 samples by Gram’s stain giving a sensitivity of 85.36%.

Antibiotics Susceptibility in Bacterial Keratitis and Proper Initial Treatment

PURPOSE: The present study aims to determine the common pathogens involved in the etiology of bacterial keratitis and to analyze not only the antibiotic susceptibility of bacterial isolates from patients with bacterial keratitis but also the propriety of initial treatment. METHODS: A retrospective study of 161 eyes in 161 patients with bacterial keratitis, who were diagnosed by cultures from 2000 to 2011, was performed. Causative bacteria and antibiotic susceptibility were evaluated in consecutive 6-year periods. RESULTS: The most common bacteria was the pseudomonas species in the 2 time periods tested and cefazolin with tobramycin was the most commonly used antibiotic (125 cases, 77.6%) for initial treatment of bacterial keratitis. In vitro testing showed gram-negative susceptibility to tobramycin and ciprofloxacin was over 70%, gram-positive susceptibility to cephalothin and vancomycin was 100% and there was no significant difference between the 2 time periods tested. Eight cases had resistance to the initial treatment, but only 1 case showed treatment failure. CONCLUSIONS: Antibiotics used for initial treatment of bacterial keratitis were able to obtain a proper effect but several cases showed bacterial resistance to antibiotics. Thus, continued testing is essential to monitor for antibiotic resistance.

Analysis of Inpatients with Contact Lens Related Bacterial Keratitis: Causative Microorganisms, Clinical Aspects, and Prognostic Factors

PURPOSE: To investigate causative microorganisms, clinical characteristics, and prognostic factors for inpatients with contact lens related bacterial keratitis. METHODS: Seventy-three eyes of inpatients with contact lens related bacterial keratitis and hospitalized at Yeungnam University Hospital between January 1998 and December 2011 were reviewed retrospectively. Their bacteriological profiles and clinical characteristics were evaluated. RESULTS: Females in their 20s (35/73 eyes, 47.9%) were the most common gender and age group. Thirty eyes (30/45 eyes, 66.7%) used daily-wear soft contact lenses. The most common predisposing factor was sleeping while wearing contact lenses (30 eyes, 41.1%). Positive culture rate was 53.4%. The ratio of gram-positive and -negative bacteria was 8.3%: 91.6%. The most commonly-isolated microorganisms were Pseudomonas spp. (39.6%), followed by Serratia spp. (29.2%). The characteristics of the corneal lesions were: a central lesion in 49 eyes (67.1%), a lesion less than 5 mm2 in size in 54 eyes (74.0%), and hypopyon in 8 eyes (11.0%). The mean log MAR BCVA improved from 0.93 +/- 0.88 on the initial visit to 0.25 +/- 0.48 on the final visit. Twelve eyes (16.4%) had a BCVA of 0.3 or less after remission medical treatment. A BCVA less than 0.1 on the initial visit was a significant risk factor for poor visual outcome (p = 0.005) after remission medical treatment. CONCLUSIONS: BCVA less than 0.1 on the initial visit, epithelial defect sized over 5 mm2, epithelial healing time over 10 days, and central corneal lesion were associated with poor visual outcome after remission medical treatment in contact lens related bacterial keratitis.

Analysis of Inpatients with Bacterial Keratitis Over a 12-Year Period: Pathogenic Organisms and Antibiotic Resistance

PURPOSE: To investigate the distribution of bacterial keratitis isolates and the shifting trends of in vitro antibiotic susceptibility of the isolates for inpatients with bacterial keratitis. METHODS: Three hundred ninety-two bacterial isolates with 366 positive culture cases from consecutive corneal scrapes of 988 clinically diagnosed bacterial keratitis inpatients hospitalized at Yeungnam University Hospital between January 1998 and December 2009 were retrospectively reviewed. The bacteriological profiles and in vitro resistance were evaluated in the first and second six-year periods. RESULTS: The percentage of positive cultures was 37.0% (366/988). The commonly isolated Gram-positive and Gram-negative organisms were S. epidermidis (98; 25.0%) and P. aeruginosa (41; 10.5%), respectively. The ratio of Gram-positive to Gram-negative isolates was 1.24:1. The Gram-positive isolates significantly decreased compared to the Gram-negative isolates in the last six-year period (45.3% versus 54.7%, respectively) relative to those in the first six-year period (66.1% versus 33.9%, respectively). S. epidermidis and S. aureus decreased, and E. cloacae, S. marcescens, and S. maltophilia increased in the last six-year period. The resistance of fluoroquinolone to the Gram-positive isolates, though not statistically significant, tended to increase to 34.1% from 21.5% (p=0.061), and the methicillin-resistant S. aureus tended to increase to 54.2% from 30.0% (p=0.055). CONCLUSIONS: S. epidermidis and P. aeruginosa were the most common bacterial keratitis isolates in Gram-positive and Gram-negative isolates. The Gram-positive isolates tended to decrease, though the Gram-negative organisms tended to increase in the last six-year period compared to the first six-year period. Empirical antibiotic selection should be based on local susceptibility patterns and distribution of bacterial isolates.

Liberação intraocular de ofloxacina associada a lente de contato biossintética em ceratite bacteriana experimental em cães / Introcular release of ofloxacin associated with biosynthetic contact lens in experimental bacterial keratitis in dogs

Avaliou-se a concentração de ofloxacina liberada por uma lente de contato de membrana de celulose biossintética, para tratamento de ceratite bacteriana experimental em cães, pela inoculação de Staphylococcus aureus intraestromal. Comparou-se o tratamento com a lente de contato biossintética impregnada com ofloxacina à terapia tópica convencional. Realizou-se avaliação microbiológica e dosagem de ofloxacina no humor aquoso por meio do método de cromatografia líquida de alto rendimento (HPLC). Houve diferença estatística na contagem de colônias bacterianas entre os olhos com ceratite e os demais grupos, no primeiro dia de coleta. O biomaterial, impregnado com ofloxacina, promoveu liberação gradual durante o período de avaliação, aos três e sete dias; no terceiro dia, o grupo tratado com a lente de contato obteve mediana de 3,72μg/mL, enquanto o grupo tratado com colírio resultou em 49,56μg/mL. Apesar do valor inferior, o grupo com lente de contato atingiu a concentração inibitória mínima, sendo eficaz no controle da infecção bacteriana.

The concentration of ofloxacin released by contact lens made of biosynthetic cellulose membrane was evaluated for the treatment of experimental bacterial keratitis in dogs by intrastromal inoculation of Staphylococcus aureus. The biosynthetic contact lens impregnated with ofloxacin was compared with the conventional topical therapy. The microbiological evaluation and the determination of ofloxacin in aqueous humor were evaluated by high performance liquid chromatography (HPLC). There was not statistical difference in the counting of bacterial colonies among the eyes with keratitis and other groups, on the first day of collection. The biomaterial, impregnated with ofloxacin, promoted gradual release during the evaluation period, at three and seven days; on the third day, the group treated with the contact lens obtained a median of 3.72μg/mL, while the group treated with eye drops resulted in 49.56μg/mL. Despite the lower value, the group with contact lens reached the minimum inhibitory concentration, which was effective in controlling the bacterial infection.