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Kathuria D, Raul AD, Wanjari P, Bharatam PV. Biguanides: Species with versatile therapeutic applications. Eur J Med Chem 2021; 219:113378. [PMID: 33857729 DOI: 10.1016/j.ejmech.2021.113378] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 03/04/2021] [Accepted: 03/08/2021] [Indexed: 12/18/2022]
Abstract
Biguanides are compounds in which two guanidine moieties are fused to form a highly conjugated system. Biguanides are highly basic and hence they are available as salts mostly hydrochloride salts, these cationic species have been found to exhibit many therapeutic properties. This review covers the research and development carried out on biguanides and accounts the various therapeutic applications of drugs containing biguanide group-such as antimalarial, antidiabetic, antiviral, anticancer, antibacterial, antifungal, anti-tubercular, antifilarial, anti-HIV, as well as other biological activities. The aim of this review is to compile all the medicinal chemistry applications of this class of compounds so as to pave way for the accelerated efforts in finding the drug action mechanisms associated with this class of compounds. Importance has been given to the organic chemistry of these biguanide derivatives also.
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Affiliation(s)
- Deepika Kathuria
- University Center for Research and Development, Chandigarh University, Gharuan, Punjab, 140413, India
| | - Akshay D Raul
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S. A. S. Nagar, 160 062, Punjab, India
| | - Pravin Wanjari
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S. A. S. Nagar, 160 062, Punjab, India
| | - Prasad V Bharatam
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S. A. S. Nagar, 160 062, Punjab, India.
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Bagga B, Sharma S, Gour RPS, Mohamed A, Joseph J, M Rathi V, Garg P. A randomized masked pilot clinical trial to compare the efficacy of topical 1% voriconazole ophthalmic solution as monotherapy with combination therapy of topical 0.02% polyhexamethylene biguanide and 0.02% chlorhexidine in the treatment of Acanthamoeba keratitis. Eye (Lond) 2020; 35:1326-1333. [PMID: 32719525 DOI: 10.1038/s41433-020-1109-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To compare the efficacy of topical voriconazole 1% and the combination therapy of 0.02% polyhexamethylene biguanide (PHMB) and 0.02% chlorhexidine for the treatment of Acanthamoeba keratitis (AK). METHODS This is a prospective, pilot, double-masked randomized comparative study. Twenty-three eyes of 23 patients with microbiologically (smear and/or growth on culture) confirmed AK were randomized to group BG (PHMB 0.02% and chlorhexidine 0.02%) or group VZ (voriconazole 1%). Primary outcome measure was change in geometric mean (GM) of the corneal ulcer size at final visit. Secondary outcome measures were change in visual acuity. RESULTS Out of 71 patients with confirmed AK seen during study period, 23 patients were recruited and 18 patients completed minimum 2 weeks of treatment and further analyzed. Ten patients received BG, whereas eight received VZ. Median ulcer size measured as GM of infiltrate decreased from 5.7 mm (IQR, 5.3-6.5 mm) (p = 0.02) to 1 mm (IQR, 0-4.3 mm) in group BG and from 4.5 mm (IQR, 1.8-5.1 mm) (p < 0.05) to 0.7 mm (IQR, 0-1.6 mm) in VZ group. Median visual acuity improved from 1.79 (IQR, 1.48-2.78) to 1.10 (IQR, 0.48-1.79) in BG group (p = 0.02) and from 1.60 (IQR, 1.00-2.78) to 0.80 (IQR, 0.48-1.30) in VZ group (p = 0.18). CONCLUSION These outcomes suggest that topical VZ as a monotherapy in AK treatment is effective and comparable to BG combination therapy but needs trials with larger sample size and longer follow-up to provide conclusive evidence.
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Affiliation(s)
- Bhupesh Bagga
- The Cornea Institute, L V Prasad Eye Institute, Hyderabad, India.
| | - Savitri Sharma
- Jhaveri Microbiology Centre, L V Prasad Eye Institute, Hyderabad, India
| | | | - Ashik Mohamed
- Ophthalmic Biophysics, L V Prasad Eye Institute, Hyderabad, India
| | - Joveeta Joseph
- Jhaveri Microbiology Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Varsha M Rathi
- The Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Prashant Garg
- The Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
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3
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Bagga B, Garg P, Joseph J, Mohamed A, Kalra P. Outcome of therapeutic deep anterior lamellar keratoplasty in advanced Acanthamoeba keratitis. Indian J Ophthalmol 2020; 68:442-446. [PMID: 32056998 PMCID: PMC7043182 DOI: 10.4103/ijo.ijo_307_19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Purpose To report and analyze the outcomes of therapeutic deep anterior lamellar keratoplasty (DALK) in patients with advanced Acanthamoeba keratitis (AK). Methods Medical records of microbiologically confirmed AK, underwent DALK from 2004 to 2017, were reviewed and the data related to early and late outcome including complications were retrieved. Outcome of cases with largest diameter of infiltrate ≥8 mm at the time of surgery (advanced keratitis) were analyzed and compared with those with less severe keratitis (infiltrate size less than 8 mm). Results Out of 23 patients of AK in whom DALK was performed, ten (43.4%) patients had advanced keratitis. Mean age of these patients was 38.7 ± 8.6 years (range, 25 to 56). Median visual acuity at presentation was 2.78 (IQR, 1.79-3.0) that improved to 1.79 (IQR, 0.70-2.78) postoperatively. Early complications included recurrence of AK in 2 (20%), Descemet's membrane detachment in 5 (50%), and persistent epithelial defect in 3 (30%) cases. Overall, 6 (60%) grafts failed, whereas 4 (40%) patients had clear graft at their last follow-up. Median follow-up of these cases was 5 months (IQR, 1.4-11.4). One graft developed stromal rejection, which resolved with increased dose of corticosteroids. In comparison, DALK performed for less severe keratitis (N = 13) had 1 (7.6%) recurrence and 2 (15.8%) grafts failure (OR, 8.25). The probability of one-year graft survival and eradication of infection was 32% and 74.1%, respectively, in advanced cases compared to 91.6% and 83.9% in less severe cases. Conclusion Outcome of DALK in advanced Acanthamoeba keratitis is less favorable compared to those carried out for less severe keratitis cases.
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Affiliation(s)
- Bhupesh Bagga
- Tej Kohli Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Prashant Garg
- Tej Kohli Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Joveeta Joseph
- Jhaveri Microbiology Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Ashik Mohamed
- Ophthalmic Biophysics, L V Prasad Eye Institute, Hyderabad, India
| | - Paavan Kalra
- Tej Kohli Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
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Lamy R, Chan E, Good SD, Cevallos V, Porco TC, Stewart JM. Riboflavin and ultraviolet A as adjuvant treatment against Acanthamoeba cysts. Clin Exp Ophthalmol 2016; 44:181-7. [PMID: 26355273 DOI: 10.1111/ceo.12644] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 08/02/2015] [Accepted: 09/07/2015] [Indexed: 01/24/2023]
Abstract
BACKGROUND Experimental studies have shown that the standard dose of riboflavin (R) or R + ultraviolet-A (UVA) as solo treatment are not able to exterminate Acanthamoeba cysts or even trophozoites. The purpose of this study is to determine whether the application of R + UVA can enhance the cysticidal effects of cationic antiseptic agents in vitro. METHODS The log of either polyhexamethylene biguanide or chlorhexidine minimal cysticidal concentration in solutions containing riboflavin (concentrations 0.1, 0.05 and 0.025%) plus either Acanthamoeba castellanii cysts or Acanthamoeba polyphaga cysts was determined and compared in groups treated with UVA 30 mW/cm(2) for 30 min and in control groups (with no exposure to UVA). A permutation test was used to determine the P value associated with treatment. RESULTS Regardless of the riboflavin concentration and UVA treatment condition, no trophozoites were seen in plates where the cysts were previously exposed to cationic antiseptic agent concentrations ≥200 µg/mL for Acanthamoeba castellanii samples and ≥100 µg/mL for A. polyphaga samples. There was no statistical evidence that R + UVA treatment was associated with minimal cysticidal concentration (P = 0.82). CONCLUSION R + UVA in doses up to 10 times higher than recommended for corneal crosslinking does not enhance the cysticidal effect of either polyhexamethylene biguanide or chlorhexidine in vitro.
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Affiliation(s)
- Ricardo Lamy
- Department of Ophthalmology, University of California - San Francisco, San Francisco, California, USA
| | - Elliot Chan
- Department of Ophthalmology, University of California - San Francisco, San Francisco, California, USA
| | - Samuel D Good
- Department of Ophthalmology, University of California - San Francisco, San Francisco, California, USA
| | - Vicky Cevallos
- Francis I. Proctor Foundation, University of California - San Francisco, San Francisco, California, USA
| | - Travis C Porco
- Francis I. Proctor Foundation, University of California - San Francisco, San Francisco, California, USA
| | - Jay M Stewart
- Department of Ophthalmology, University of California - San Francisco, San Francisco, California, USA
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Rahimi F, Hashemian SMN, Tafti MF, Mehjerdi MZ, Safizadeh MS, Pour EK, Sefidan BB. Chlorhexidine Monotherapy with Adjunctive Topical Corticosteroids for Acanthamoeba Keratitis. J Ophthalmic Vis Res 2015; 10:106-11. [PMID: 26425310 PMCID: PMC4568605 DOI: 10.4103/2008-322x.163782] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 01/07/2015] [Indexed: 11/04/2022] Open
Abstract
PURPOSE To assess the efficacy of chlorhexidine monotherapy for Acanthamoeba keratitis, and to determine the therapeutic outcomes of concomitant topical corticosteroids. METHODS In this prospective interventional case series, 31 eyes of 31 patients with Acanthamoeba keratitis (AK) were treated with chlorhexidine 0.02% as monotherapy, from April 2010 to April 2011. The diagnosis of AK was made based on clinical manifestations and positive confocal microscopic (confoscan 3.4, Nidek Co. Ltd., Gamagori, Japan) results. We report the percentage of a favorable clinical response within two weeks of initiating treatment, worsening of the infection while receiving chlorhexidine, recovery of visual acuity (VA), duration of treatment with chlorhexidine and corticosteroids, necessity for addition of other anti-Acanthamoeba agents, presence of corneal scar at the end of the treatment, and need for penetrating keratoplasty (PK). RESULTS Two weeks after initiation of chlorhexidine, improvement in signs and symptoms was observed in 26 (83.9%) patients but 3 eyes required the addition of propamidine. After initial improvement in one patient, the infection worsened, necessitating the addition of Polyhexamethylene Biguanide (PHMB) and propamidine. A total of 26 (83.9%) patients received topical corticosteroids with mean duration of 65.8 ± 45.1 days. In 22 (71%) eyes, final visual acuity was ≥0.80. Improved VA occurred in 29 eyes (93.5%). Optical PK was considered in 3 (9.7%) eyes and a corneal scar developed in 8 (25.8%) eyes. CONCLUSION Chlorhexidine is effective for monotherapy in AK and could be a good choice for initiating treatment. After the initial response to anti-Acanthamoeba agents, corticosteroids can be used as adjunctive therapy depending on the clinical condition.
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Affiliation(s)
- Firoozeh Rahimi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | | | - Mona Seyed Safizadeh
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Elias Khalili Pour
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahram Bohrani Sefidan
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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PrestoBlue® and AlamarBlue® are equally useful as agents to determine the viability of Acanthamoeba trophozoites. Exp Parasitol 2014; 145 Suppl:S69-72. [PMID: 24703973 DOI: 10.1016/j.exppara.2014.03.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 03/19/2014] [Accepted: 03/23/2014] [Indexed: 11/23/2022]
Abstract
Acanthamoeba is an opportunistic pathogen which is the causal agent of several human infections such as Granulomatous Amoebic Encephalitis, Acanthamoeba keratitis and other disseminated infections. Furthermore, current therapeutic measures against Acanthamoeba infections are arduous, and show limited efficacy against the cyst stage of Acanthamoeba. There is a pressing need to search and evaluate new therapeutic agents against these protozoa. Our approach for evaluating possible new drugs is an initial in vitro screening assay based on general metabolic activity of the cells. In this study we compare two agents, AlamarBlue® and PrestoBlue® for this initial screen. Both reagents can be used to indicate metabolism by changes in their absorbance or fluorescence. The assay is carried out in a 96-well plate format and fluorescence can be measured after an inoculation period of as little as 10 min, but more typically 96 h. This to the best of our knowledge this is the first time that both compounds are directly compared using absorbance and fluorescence measurement. We conclude that for the specific case of Acanthamoeba both agents AlamarBlue® and PrestoBlue® are equally useful to determine cell viability.
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Ferrari G, Matuska S, Rama P. Double-biguanide therapy for resistant acanthamoeba keratitis. Case Rep Ophthalmol 2011; 2:338-42. [PMID: 22174703 PMCID: PMC3238035 DOI: 10.1159/000334270] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Aims To report the clinical and diagnostic findings of a patient with Acanthamoeba keratitis resistant to both polyhexamethylene biguanide (PHMB)-hexamidine and chlorhexidine-hexamidine treatment. Methods Slit-lamp biomicroscopy, corneal cell scraping and histopathology were performed on a 39-year-old woman presenting with corneal ulcer in her left eye. Results The patient was successfully treated with PHMB-chlorhexidine association therapy. Subsequent perforating keratoplasty remained clear at the last follow-up visit after 7 months and increased visual acuity to 20/20 with correction. Conclusions This case emphasizes the proteiform aspects of Acanthamoeba drug resistance, and suggests that PHMB-chlorhexidine association might represent an additional option for cases resistant to standard therapy.
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Abstract
Acanthamoeba keratitis is a rare but severe disease, with more than 95% of cases occurring in contact lens wearers. With a worldwide resurgence of contact lens-related disease, this report illustrates the clinical characteristics and treatment challenges representative of this disease. This report describes Acanthamoeba keratitis in a 47-year-old female using extended wear silicone hydrogel contact lenses, with a history of swimming in a home pool and failure to subsequently disinfect the contact lenses. The diagnosis was based on clinical signs, disease course, and confocal microscopy results despite a negative result for corneal smear and culture. The corneal signs included an epithelial defect, epithelial irregularities, anterior stromal infiltrates, perineural infiltrates, an anterior stromal ring infiltrate, and hypopyon. The case was diagnosed as an infective keratitis and treated promptly using intensive topical administration of fortified gentamicin and cephalothin. The high likelihood Acanthamoeba prompted immediate use of polyhexamethylbiguanide and chlorhexidine, with propamide and adjunct treatment using atropine and oral diclofenac. Steroids were added on day 3, and the frequency of administration of antibacterial treatment was gradually reduced and ceased by day 10. The analgesia was stopped at 3 months. The frequency of administration of antiamoeba therapy and steroid treatment was slowly reduced and all treatment was ceased after 18 months. Despite considerable morbidity in terms of the treatment duration, hospitalization, outpatient appointments, and associated disease costs, the final visual outcome (6/6) was excellent.
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Lee JE, Oum BS, Choi HY, Yu HS, Lee JS. Cysticidal Effect on Acanthamoeba and Toxicity on Human Keratocytes by Polyhexamethylene Biguanide and Chlorhexidine. Cornea 2007; 26:736-41. [PMID: 17592327 DOI: 10.1097/ico.0b013e31805b7e8e] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the cysticidal effect of polyhexamethylene biguanide (PHMB) and chlorhexidine on Acanthamoeba and its toxic effect on cultured human keratocytes. METHODS Each well of a twofold-diluted Acanthamoeba cyst-containing suspension of 5 x 10(4) cysts/mL was treated with PHMB and chlorhexidine for 8, 24, and 48 hours to determine the minimal cysticidal concentration (MCC) of each disinfectant. Human corneal keratocytes (5 x 10(4) cells/mL) were exposed to PHMB and chlorhexidine for the same time to determine the survival rate of keratocytes. Inverted phase-contrast and electron microscopy were used to observe the morphologic changes. RESULTS The mean MCC of PHMB for 8, 24, and 48 hours was 9.42, 5.62, and 2.37 microg/mL, respectively. The mean MCC of chlorhexidine for 8, 24, and 48 hours was 24.32, 10.02, and 7.02 microg/mL, respectively. The respective survival rate of keratocytes at the MCC was 91.7%, 64.6%, and 49.7% for PHMB and 95.7%, 90.6%, and 78.1% for chlorhexidine, respectively. The cysts and keratocytes showed more damaged appearances after treatment with PHMB than chlorhexidine. CONCLUSIONS PHMB and chlorhexidine showed a similar amoebicidal efficacy. However, PHMB seemed to be more toxic to keratocytes than chlorhexidine.
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Affiliation(s)
- Ji-Eun Lee
- Department of Ophthalmology, Pusan National University Hospital, Pusan, Korea
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Ibrahim YW, Boase DL, Cree IA. Factors affecting the epidemiology of Acanthamoeba keratitis. Ophthalmic Epidemiol 2007; 14:53-60. [PMID: 17464851 DOI: 10.1080/09286580600920281] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Despite being a relatively rare disease in comparison with other forms of infectious keratitis, Acanthamoeba keratitis is a potentially blinding disease. Wide variations in the incidence of Acanthamoeba keratitis have been reported in both developed and developing countries. At the same time that contact lens wear was found to be responsible for the spread of the disease in developed countries, Acanthamoeba keratitis was considered a rare disease in developing countries compared with fungal and bacterial keratitis. In recent decades, the risk of getting Acanthamoeba keratitis has increased because of the increased proportion of contact lens wearers. This article introduces the different factors affecting the epidemiology of Acanthamoeba keratitis worldwide, presents a chronological review of the literature, and shows the progressive spread of Acanthamoeba keratitis in the last two decades in different geographical areas of the world. A detailed comparison of the incidence of the disease as reported in different studies in different countries is made. The impact of contact lenses and other factors, such as hot weather, virulence of Acanthamoeba strains, water sanitation and quality, the occurrence of environmental disasters such as flooding, and the wide environmental presence of Acanthamoeba cysts on the incidence of the disease, are discussed. In addition, the ability of Acanthamoeba cysts to resist different harsh conditions is reviewed.
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Affiliation(s)
- Youhanna W Ibrahim
- Department of Ophthalmology, Queen Alexandra Hospital, Portsmouth, United Kingdom.
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Abstract
PURPOSE Acanthamoeba keratitis is a potentially blinding microbial disease that has been increasing in incidence during the past two decades. Prognosis of this serious disease had been dismal, but improvement in diagnosis, a better understanding of the natural course of the disease, and recent introduction of multiple and effective therapeutic agents have resulted in improvement of visual outcomes. METHODS A review of literature pertaining to Acanthamoeba keratitis. RESULTS Contact lens wear and exposure to contaminated water sources remain the most important risk factors; however, in vivo confocal microscopy and improved biomicroscopic screening have proven instrumental in accurate early diagnosis. Complications of Acanthamoeba keratitis include dacryoadenitis, corneal melting and scarring, severe secondary glaucoma, cataract, and chronic anterior segment inflammation that can rarely lead to reactive blinding retinal ischemia. Combination chemotherapeutic agents have been shown to be more effective than monotherapy, whereas rehabilitative surgery such as penetrating keratoplasty is best performed on a quiet eye free of ocular inflammation and with no residual amoebae. CONCLUSIONS Increased suspicion by clinicians for Acanthamoeba and confocal microscopy have allowed more rapid and accurate diagnosis; treatment with multiple antiamoeba drugs is essential to disease resolution. Provided there are no residual amoebae after treatment, penetrating keratoplasty has been successful in visual rehabilitation. Secondary glaucoma occurs frequently and may require drainage procedures for control of intraocular pressure. Posterior complications are rare but may lead to ischemic retinitis.
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Affiliation(s)
- Shady T Awwad
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA
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Abstract
PURPOSE To compare the amoebicidal activity of two commercially available multipurpose contact lens care systems, by using cyst and trophozoite growth of two strains each of Acanthamoeba castellanii and Acanthamoeba polyphaga. METHODS Trophozoites and cysts of Acanthamoeba species, isolated from corneal ulcers and an ATCC strain, were exposed to two commonly used multipurpose solutions and a saline control for 4 or 6 hours at ambient temperature. After neutralization of the disinfecting solution, track forming units were enumerated on Escherichia coli-seeded nutrient agar plates. RESULTS There were significant differences (P<0.01) between solutions, strains, and cysts or trophozoites, but not between the different periods. Solution 2, containing polyquaternium-1 and myristamidopropyl dimethylamine (among other ingredients), gave greater mean log reductions than did solution 1, containing polyaminopropyl biguanide and poloxamine (among other ingredients). Both solutions generally reduced more trophozoites than cysts. CONCLUSIONS The multipurpose solution containing polyquaternium-1 and myristamidopropyl dimethylamine reduced more cysts and trophozoites than did the alternative solution tested. Because there were differences in the effect of the multipurpose solutions on strains, it is recommended that more than one strain or species of Acanthamoeba be tested to determine efficacy of disinfecting solutions. The lack of difference between disinfection times may indicate that 4 hours could be considered as an adequate disinfecting time to ensure sufficient kill of Acanthamoeba species.
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Affiliation(s)
- Sally L Buck
- Alcon Research, Ltd., Fort Worth, TX 76134, USA.
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Turner NA, Russell AD, Furr JR, Lloyd D. Resistance, biguanide sorption and biguanide-induced pentose leakage during encystment of Acanthamoeba castellanii. J Appl Microbiol 2004; 96:1287-95. [PMID: 15139921 DOI: 10.1111/j.1365-2672.2004.02260.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIMS This study investigates the effects of biguanides during encystment of Acanthamoeba castellanii. METHODS AND RESULTS A non-nutrient encystment system was used to investigate the changes in the levels of sorption (uptake) of three non-cysticidal concentrations (10, 20 and 50 microg ml(-1)) of chlorhexidine diacetate (CHA) and polyhexamethylene biguanide (PHMB) as well as their effects on viability and leakage of pentose sugars during the first 36 h of encystment. Trophozoites treated with CHA or PHMB were more sensitive and generally sorbed more of each biocide than cysts. During encystment, the largest increases in resistance developed between 18 and 36 h for both biguanides with the resistance emerging to biguanide concentrations of 10 or 20 microg ml(-1) between 18 and 24 h. At 50 microg ml(-1) resistance emerged between 24 and 36 h. There was a general decrease in biocide sorption during encystment between 0-24 and 0-21 h for CHA and PHMB, respectively, at a concentration of 50 microg ml(-1). The greatest decline in biguanide-induced pentose leakage was between 0 and 12 h. CONCLUSIONS The results suggest that during encystment some of the changes in the susceptibility to CHA or PHMB may be related to decreases in the levels of biocide sorption, which is limited by the developing cyst wall. SIGNIFICANCE AND IMPACT OF THE STUDY During encystation, changes occur in biguanide sensitivity. The physical barrier of the cyst wall may be an important factor in limiting biocide sorption.
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Affiliation(s)
- N A Turner
- Department of Medical and Molecular Parasitology, New York University School of Medicine, New York, NY 10010, USA.
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Kumar R, Lloyd D. Recent advances in the treatment of Acanthamoeba keratitis. Clin Infect Dis 2002; 35:434-41. [PMID: 12145728 DOI: 10.1086/341487] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2001] [Revised: 03/26/2002] [Indexed: 11/03/2022] Open
Abstract
Infection of the eye caused by Acanthamoeba species constitutes a burgeoning and unsolved problem. Of individuals with Acanthamoeba keratitis, 85% wear contact lenses; abrasion of the cornea is implicated. Corneal infection often can be prevented by good lens care and hygiene. Severe Acanthamoeba keratitis often can be very difficult to treat; surgery can be less than successful and may lead to further problems. The encysted stage in the life cycle of Acanthamoeba species appears to cause the most problems; many biocides are ineffective in killing the highly resistant cysts. Combination therapy--that is, use of 2 or 3 biocides, sometimes with antibacterial antibiotics--appears to work best. Recurrence is common if treatment is stopped prematurely. Immunologic methods are being investigated as a form of prevention, and oral immunization of animals recently has been successful in the prevention of Acanthamoeba keratitis by inducing immunity before infection occurs. Immunization thus may eventually become the best approach for reduction of the incidence of amebic infection in humans.
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Affiliation(s)
- Raman Kumar
- Department of Microbiology, Cardiff University, Wales, United Kingdom
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Noble JA, Ahearn DG, Avery SV, Crow Jr. SA. Phagocytosis affects biguanide sensitivity of Acanthamoeba spp. Antimicrob Agents Chemother 2002; 46:2069-76. [PMID: 12069957 PMCID: PMC127298 DOI: 10.1128/aac.46.7.2069-2076.2002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2001] [Revised: 02/11/2002] [Accepted: 04/02/2002] [Indexed: 11/20/2022] Open
Abstract
The incidence of Acanthamoeba keratitis, a disease associated with contact lens wear, has been in apparent decline with the advent of multipurpose contact lens solutions. The concentrations of the biguanides chlorhexidine digluconate (CHX) and particularly polyhexamethylene biguanide (PHMB) included in multipurpose solutions (MPSs) are sublethal for amoebae. We evaluated by flow cytometry the effects of these two biguanides on phagocytosis of particles and the survival of trophozoites of Acanthamoeba castellanii and A. polyphaga. Trophozoites of A. castellanii and A. polyphaga (10(6)/ml) were exposed to solutions of 5 and 50 microg of PHMB and CHX per ml in the presence and absence of particles (i.e., heat-killed yeasts and bacteria and latex beads). In addition, trophozoites were exposed to particles treated with these concentrations of the two biguanides. In the absence of particles, trophozoites of A. polyphaga appeared to be more resistant to the biguanides than those of A. castellanii. In the presence of particles, the rates of survival of both species were decreased. In most instances, particles treated with sublethal concentrations of both biguanides that were adsorbed onto the particles reduced the incidence of phagocytosis. Particles present in MPSs in contact lens cases may be involved in the decreased incidence of Acanthamoeba keratitis.
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Affiliation(s)
- Judith A. Noble
- Department of Biology, Georgia State University, University Plaza, Atlanta, Georgia 30303, School of Life and Environmental Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Donald G. Ahearn
- Department of Biology, Georgia State University, University Plaza, Atlanta, Georgia 30303, School of Life and Environmental Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Simon V. Avery
- Department of Biology, Georgia State University, University Plaza, Atlanta, Georgia 30303, School of Life and Environmental Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Sidney A. Crow Jr.
- Department of Biology, Georgia State University, University Plaza, Atlanta, Georgia 30303, School of Life and Environmental Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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Sharma S, Garg P, Rao GN. Patient characteristics, diagnosis, and treatment of non-contact lens related Acanthamoeba keratitis. Br J Ophthalmol 2000; 84:1103-8. [PMID: 11004092 PMCID: PMC1723254 DOI: 10.1136/bjo.84.10.1103] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIM To review the clinical characteristics, diagnosis, and visual outcome in patients with non-contact lens related Acanthamoeba keratitis and compare the findings with reported series of contact lens associated Acanthamoeba keratitis. METHODS Medical and microbiology records of 39 consecutive patients with a diagnosis of Acanthamoeba keratitis, at a tertiary eyecare centre in India between January 1996 and June 1998, were analysed retrospectively. RESULTS A majority of the patients presented with poor visual acuity and large corneal stromal infiltrates (mean size 38.20 (SD 26. 18) mm). A predisposing factor was elicited in 19/39 (48.7%) patients (trauma 15, dirty water splash three, leaf juice one). None of the patients had worn contact lenses. Most patients (26/39 (66. 6%)) came from a low socioeconomic background. Complaint of severe pain was not a significant feature and radial keratoneuritis was seen in 1/39 (2.5%) patients. A ring infiltrate was present in 41.1% of cases. A clinical diagnosis of fungal keratitis was made in 45% of the patients before they were seen by us. However, all patients were diagnosed microbiologically at our institute based on demonstration of Acanthamoeba cysts in corneal scrapings (34/39) and/or culture of Acanthamoeba (34/39). Treatment with biguanides (PHMB, 15/38 (39.4%), PHMB with CHx, 23/38 (60.5%), one patient did not return for treatment) resulted in healing with scar formation in 27 out of 31(87.0%) followed up patients (mean time to healing 106.9 days). Overall visual outcome was poor with no statistical difference between cases diagnosed within 30 days (early) or 30 days after (late) start of symptoms. The visual outcome in cases requiring tissue adhesive (five) and keratoplasty (three) was also poor. CONCLUSIONS This is thought to be the largest series of cases of Acanthamoeba keratitis in non-contact lens wearers. In such cases, the disease is advanced at presentation in most patients, pathognomonic clinical features are often not seen, disease progression is rapid, and visual outcome is usually poor. Possible existence of Acanthamoeba pathotypes specifically associated with non-contact lens keratitis and unique to certain geographical areas is suggested.
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Affiliation(s)
- S Sharma
- Jhaveri Microbiology Centre, LV Prasad Eye Institute, LV Prasad Marg, Banjara Hills, Hyderabad-500 034, India.
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Borazjani RN, May LL, Noble JA, Avery SV, Ahearn DG. Flow cytometry for determination of the efficacy of contact lens disinfecting solutions against Acanthamoeba spp. Appl Environ Microbiol 2000; 66:1057-61. [PMID: 10698771 PMCID: PMC91942 DOI: 10.1128/aem.66.3.1057-1061.2000] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flow cytometric analyses of cellular staining with fluorescent viability dyes and direct microscopic observations of methylene blue exclusion were compared for evaluation of the effects of a chlorhexidine gluconate-based contact lens disinfectant solution and a polyhexamethylene biguanide solution against cysts and trophozoites of Acanthamoeba castellanii and Acanthamoeba polyphaga. The flow cytometric procedure with propidium iodide (used to stain dead cells) indicated that more than 90% of trophozoites of both species (inocula of 10(5) to 10(6)/ml) at 22 degrees C lost their viability after 4 h of exposure to chlorhexidine. When propidium iodide was used in combination with fluorescein diacetate (for live cells), the apparent number of propidium iodide-stained cells was reduced, but the relative efficacies of the two biguanide solutions appeared unchanged from those evident with the single dyes; the chlorhexidine solution was more effective than the polyhexamethylene biguanide solution. Similar data were obtained with the more cumbersome methylene blue exclusion procedure. Flow cytometric analyses provided a statistically reproducible and rapid procedure for determining the relative antiamoebal efficacies of the disinfecting solutions.
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Affiliation(s)
- R N Borazjani
- Department of Biology, Georgia State University, Atlanta, Georgia 30303, USA
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Gatti S, Cevini C, Bruno A, Penso G, Rama P, Scaglia M. In vitro effectiveness of povidone-iodine on Acanthamoeba isolates from human cornea. Antimicrob Agents Chemother 1998; 42:2232-4. [PMID: 9736540 PMCID: PMC105790 DOI: 10.1128/aac.42.9.2232] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acanthamoeba keratitis is a severe ocular infection secondary to accidental macro- or microscopic trauma of the cornea. Starting in 1985, a dramatic increase of this infection was recorded along with the spread of contact lens use. This protozoal disease is difficult to treat because of the scarcity of efficacious topical and systemic drugs. We evaluated the in vitro effectiveness of povidone-iodine (PVP-I [Betadine]), an agent with broad antibacterial and antiviral activity, compared to that of chlorhexidine (CXD), a cationic antiseptic, on Acanthamoeba isolates from patients with amebic keratitis. The results showed that PVP-I solution from 0.5 to 2.5% has a better antiamebic activity both on trophic and cystic stages of Acanthamoeba spp. than does CXD.
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Affiliation(s)
- S Gatti
- Laboratory of Parasitology, Virology Unit, IRCCS, San Matteo, Pavia, Italy
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19
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Abstract
Acanthamoeba species are an important cause of microbial keratitis that may cause severe ocular inflammation and visual loss. The first cases were recognized in 1973, but the disease remained very rare until the 1980s, when an increase in incidence mainly associated with contact lens wear was reported. There is an increased risk when contact lens rinsing and soaking solutions are prepared with nonsterile water and salt tablets. The clinical picture is often characterized by severe pain with an early superficial keratitis that is often treated as herpes simplex infection. Subsequently a characteristic radial perineural infiltration may be seen, and ring infiltration is common. Limbitis and scleritis are frequent. Laboratory diagnosis is primarily by culture of epithelial samples inoculated onto agar plates spread with bacteria. Direct microscopy of samples using stains for the cyst wall or immunostaining may also be employed. A variety of topically applied therapeutic agents are thought to be effective, including propamidine isethionate, clotrimazole, polyhexamethylene biguanide, and chlorhexidine. Various combinations of these and other agents have been employed, often resulting in medical cure, especially if treatment is commenced early in the course of the disease. Penetrating keratoplasty is preferably avoided in inflamed eyes, but may be necessary in severe cases to preserve the globe or, when the infection has resolved, to restore corneal clarity for optical reasons.
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Kong HH, Chung DI. Ultrastructural changes of Acanthamoeba cyst of clinical isolates after treatment with minimal cysticidal concentration of polyhexamethylene biguanide. THE KOREAN JOURNAL OF PARASITOLOGY 1998; 36:7-13. [PMID: 9529858 DOI: 10.3347/kjp.1998.36.1.7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In order to understand the action mechanism of polyhexamethylene biguanide (PHMB) to the cyst of Acanthamoeba on the morphological basis, the cysts of four corneal isolates of Acanthamoeba were treated with minimal cysticidal concentration (MCC) of PHMB and their ultrastructural changes were examined by transmission electron microscopy. The most striking change of cysts treated with PHMB compared with normal cysts was the shrinkage of intracystic amoebae, which resulted in the separation of the plasma membrane of intracystic amoeba from endocystic wall. Subplasmalemmal lipid droplets became irregularly shaped. In severely damaged cysts, cytoplasm was aggregated and organelles were severely deformed. Cytoplasmic materials were leaked out through the damaged plasma membrane. Most cysts showed aggregation of nuclear chromatin material. Number of mitochondrial cristae was also reduced. Ecto- and endo-cystic walls were relatively well tolerated. Findings in the present study revealed that PHMB affected mainly on plasma membrane, but lesser on organellar membrane of intracystic amoeba. It seemed likely that PHMB might kill cystic forms of Acanthamoeba by similar mechanism in which this environmental biocide can damage the cell wall of Escherichia coli by binding with acidic phospholipids.
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Affiliation(s)
- H H Kong
- Department of Parasitology, Kyungpook National University School of Medicine, Taegu, Korea
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Ahearn DG, Gabriel MM. Contact lenses, disinfectants, and Acanthamoeba keratitis. ADVANCES IN APPLIED MICROBIOLOGY 1997; 43:35-56. [PMID: 9097411 DOI: 10.1016/s0065-2164(08)70222-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- D G Ahearn
- Department of Biology, Georgia State University, Atlanta 30302-4010, USA
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