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McClure JA, Lakhundi S, Niazy A, Dong G, Obasuyi O, Gordon P, Chen S, Conly JM, Zhang K. Staphylococcus aureus ST59: Concurrent but Separate Evolution of North American and East Asian Lineages. Front Microbiol 2021; 12:631845. [PMID: 33643261 PMCID: PMC7902796 DOI: 10.3389/fmicb.2021.631845] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 01/20/2021] [Indexed: 11/30/2022] Open
Abstract
Despite initially being described in North America, Staphylococcus aureus (SA) sequence type ST59 is the most commonly isolated sequence type in Eastern Asia. The origins and evolution of this strain type remains unclear and therefore we gathered a collection of ST59 isolates from Canada and mainland China for a detailed genetic analysis of the lineage. Bayesian inference phylogenomic analysis of our isolates, along with previously published ST59 sequences indicated that the lineage could be divided into 6 distinct subgroups (WGS-1 thorough 6), each having distinct molecular characteristics. Analysis also demonstrated the concurrent but separate evolution of North American and East Asian lineages, as well as the extensive diversification of the East Asian lineage. The presence of a mobile element structure (MES) was found to be the major difference between these two continental lineages, absent in all North American isolates, and present in all East Asian ones. Other mobile genetic elements, such as the Immune Evasion Complex (IEC), Panton Valentine Leukocidin (PVL), and Staphylococcal Cassette Chromosome mec (SCCmec), showed significant variability within each sub-group and likely represents local selective pressures rather than major characteristics defining the groups. Our analysis also demonstrated the existence of a more ancient ST59 sub-lineage from North America, which was MES negative and contained some of the earliest reported ST59 isolates. Combined with the existence of a MES negative isolate from Taiwan, predicted to have appeared prior to diversification of the East Asian lineages, these results hint at the possibility of a North American origin for the lineage, which gained hold in Eastern Asia following acquisition of MES, and subsequently diversified.
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Affiliation(s)
- Jo-Ann McClure
- Centre for Antimicrobial Resistance, Alberta Health Services/Alberta Precision Laboratories/University of Calgary, Calgary, AB, Canada
| | - Sahreena Lakhundi
- Department of Pathology & Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Amani Niazy
- Department of Pathology & Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - George Dong
- Department of Pathology & Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Osahon Obasuyi
- Department of Pathology & Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Paul Gordon
- Centre for Health Genomics and Informatics, University of Calgary, Calgary, AB, Canada
| | - Sidong Chen
- Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China
| | - John M Conly
- Centre for Antimicrobial Resistance, Alberta Health Services/Alberta Precision Laboratories/University of Calgary, Calgary, AB, Canada.,Department of Pathology & Laboratory Medicine, University of Calgary, Calgary, AB, Canada.,Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada.,Department of Medicine, University of Calgary, Calgary, AB, Canada.,The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Kunyan Zhang
- Centre for Antimicrobial Resistance, Alberta Health Services/Alberta Precision Laboratories/University of Calgary, Calgary, AB, Canada.,Department of Pathology & Laboratory Medicine, University of Calgary, Calgary, AB, Canada.,Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada.,Department of Medicine, University of Calgary, Calgary, AB, Canada.,The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
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Kashif A, McClure JA, Lakhundi S, Pham M, Chen S, Conly JM, Zhang K. Staphylococcus aureus ST398 Virulence Is Associated With Factors Carried on Prophage ϕSa3. Front Microbiol 2019; 10:2219. [PMID: 31608039 PMCID: PMC6771273 DOI: 10.3389/fmicb.2019.02219] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 09/11/2019] [Indexed: 02/01/2023] Open
Abstract
An increasing number of severe infections caused by Staphylococcus aureus ST398 strains has been observed. However, it has not been elucidated whether all ST398 strains are equally virulent. We collected 13 strains from China and Canada to test in a Caenorhabditis elegans infection model and compared their whole genome sequences (WGS) to explore potential insights into their virulence. All isolates belonged to ST398-methicillin-susceptible S. aureus (MSSA) with variant spa types (t034, t571, t1451, t1250). Pulsed field gel electrophoresis (PFGE) and WGS analyses showed that the 13 isolates clustered into 3 genomic types (Types A-C). WGS and prophage phylogenetic analyses also revealed that the strains could be divided into 3 phage groups (Groups 1–3), which correlated with high-, moderate-, and low-nematocidal activities, with mean killing rates of 94, 67, and 40%, respectively. Group 1 carried ϕSa3-Group 1 (ϕSa3-G1), Group 2 carried ϕSa3-G2, and Group 3 lacked ϕSa3. Interestingly, strain GD1706 (that genetically clustered within Type C) and strain GD487 (within Type B) both carried ϕSa3-G1 like phages and killed 92% of the nematodes, similar to the Type A strains carrying ϕSa3-G1. This study demonstrated that different ST398 sub-lineages possess variable virulence capacities, depending on the presence or absence, as well as the structure of the prophage ϕSa3 that carries virulence factors.
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Affiliation(s)
- Ayesha Kashif
- Centre for Antimicrobial Resistance, Alberta Health Services/Alberta Public Laboratories/University of Calgary, Calgary, AB, Canada
| | - Jo-Ann McClure
- Centre for Antimicrobial Resistance, Alberta Health Services/Alberta Public Laboratories/University of Calgary, Calgary, AB, Canada
| | - Sahreena Lakhundi
- Centre for Antimicrobial Resistance, Alberta Health Services/Alberta Public Laboratories/University of Calgary, Calgary, AB, Canada
| | - Michael Pham
- Centre for Antimicrobial Resistance, Alberta Health Services/Alberta Public Laboratories/University of Calgary, Calgary, AB, Canada
| | - Sidong Chen
- Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China
| | - John M Conly
- Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China.,Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China.,Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China.,Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China.,Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China
| | - Kunyan Zhang
- Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China.,Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China.,Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China.,Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China.,Department of Epidemiology and Health Statistics, Guangdong Pharmaceutical University, Guangzhou, China
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Abstract
Staphylococcus aureus, a major human pathogen, has a collection of virulence factors and the ability to acquire resistance to most antibiotics. This ability is further augmented by constant emergence of new clones, making S. aureus a "superbug." Clinical use of methicillin has led to the appearance of methicillin-resistant S. aureus (MRSA). The past few decades have witnessed the existence of new MRSA clones. Unlike traditional MRSA residing in hospitals, the new clones can invade community settings and infect people without predisposing risk factors. This evolution continues with the buildup of the MRSA reservoir in companion and food animals. This review focuses on imparting a better understanding of MRSA evolution and its molecular characterization and epidemiology. We first describe the origin of MRSA, with emphasis on the diverse nature of staphylococcal cassette chromosome mec (SCCmec). mecA and its new homologues (mecB, mecC, and mecD), SCCmec types (13 SCCmec types have been discovered to date), and their classification criteria are discussed. The review then describes various typing methods applied to study the molecular epidemiology and evolutionary nature of MRSA. Starting with the historical methods and continuing to the advanced whole-genome approaches, typing of collections of MRSA has shed light on the origin, spread, and evolutionary pathways of MRSA clones.
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Affiliation(s)
- Sahreena Lakhundi
- Centre for Antimicrobial Resistance, Alberta Health Services/Calgary Laboratory Services/University of Calgary, Calgary, Alberta, Canada
| | - Kunyan Zhang
- Centre for Antimicrobial Resistance, Alberta Health Services/Calgary Laboratory Services/University of Calgary, Calgary, Alberta, Canada
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
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McClure JAM, Lakhundi S, Kashif A, Conly JM, Zhang K. Genomic Comparison of Highly Virulent, Moderately Virulent, and Avirulent Strains From a Genetically Closely-Related MRSA ST239 Sub-lineage Provides Insights Into Pathogenesis. Front Microbiol 2018; 9:1531. [PMID: 30042755 PMCID: PMC6048232 DOI: 10.3389/fmicb.2018.01531] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/20/2018] [Indexed: 12/19/2022] Open
Abstract
The genomic comparison of virulent (TW20), moderately virulent (CMRSA6/CMRSA3), and avirulent (M92) strains from a genetically closely-related MRSA ST239 sub-lineage revealed striking similarities in their genomes and antibiotic resistance profiles, despite differences in virulence and pathogenicity. The main differences were in the spa gene (coding for staphylococcal protein A), lpl genes (coding for lipoprotein-like membrane proteins), cta genes (genes involved in heme synthesis), and the dfrG gene (coding for a trimethoprim-resistant dihydrofolate reductase), as well as variations in the presence or content of some prophages and plasmids, which could explain the virulence differences of these strains. TW20 was positive for all genetic traits tested, compared to CMRSA6, CMRSA3, and M92. The major components differing among these strains included spa and lpl with TW20 carrying both whereas CMRSA6/CMRSA3 carry spa identical to TW20 but have a disrupted lpl. M92 is devoid of both these traits. Considering the role played by these components in innate immunity and virulence, it is predicted that since TW20 has both the components intact and functional, these traits contribute to its pathogenesis. However, CMRSA6/CMRSA3 are missing one of these components, hence their intermediately virulent nature. On the contrary, M92 is completely devoid of both the spa and lpl genes and is avirulent. Mobile genetic elements play a potential role in virulence. TW20 carries three prophages (ϕSa6, ϕSa3, and ϕSPβ-like), a pathogenicity island and two plasmids. CMRSA6, CMRSA3, and M92 contain variations in one or more of these components. The virulence associated genes in these components include staphylokinase, entertoxins, antibiotic/antiseptic/heavy metal resistance and bacterial persistence. Additionally, there are many hypothetical proteins (present with variations among strains) with unknown function in these mobile elements which could be making an important contribution in the virulence of these strains. The above mentioned repertoire of virulence components in TW20 likely contributes to its increased virulence, while the absence and/or modification of one or more of these components in CMRSA6/CMRSA3 and M92 likely affects the virulence of the strains.
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Affiliation(s)
- Jo-Ann M. McClure
- Centre for Antimicrobial Resistance, Alberta Health Services/Calgary Laboratory Services/University of Calgary, Calgary, AB, Canada
| | - Sahreena Lakhundi
- Centre for Antimicrobial Resistance, Alberta Health Services/Calgary Laboratory Services/University of Calgary, Calgary, AB, Canada
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada
| | - Ayesha Kashif
- Centre for Antimicrobial Resistance, Alberta Health Services/Calgary Laboratory Services/University of Calgary, Calgary, AB, Canada
| | - John M. Conly
- Centre for Antimicrobial Resistance, Alberta Health Services/Calgary Laboratory Services/University of Calgary, Calgary, AB, Canada
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
- Department of Medicine, University of Calgary, Calgary, AB, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Kunyan Zhang
- Centre for Antimicrobial Resistance, Alberta Health Services/Calgary Laboratory Services/University of Calgary, Calgary, AB, Canada
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
- Department of Medicine, University of Calgary, Calgary, AB, Canada
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
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Lakhundi S, Siddiqui R, Khan NA. Pathogenesis of microbial keratitis. Microb Pathog 2017; 104:97-109. [DOI: 10.1016/j.micpath.2016.12.013] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 11/30/2016] [Accepted: 12/05/2016] [Indexed: 01/03/2023]
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Siddiqui R, Lakhundi S, Iqbal J, Khan NA. Effect of non-steroidal anti-inflammatory drugs on biological properties of Acanthamoeba castellanii belonging to the T4 genotype. Exp Parasitol 2016; 168:45-50. [PMID: 27381503 DOI: 10.1016/j.exppara.2016.06.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/29/2016] [Indexed: 10/21/2022]
Abstract
Non-steroidal anti-inflammatory drug, Diclofenac, targeting COX have shown promise in the treatment of Acanthamoeba keratitis, but the underlying mechanisms remain unknown. Using various NSAIDs, Diclofenac sodium, Indomethacin, and Acetaminophen, here we determined the effects of NSAIDs on the biological properties of Acanthamoeba castellanii belonging to the T4 genotype. Using amoebicidal assays, the results revealed that Diclofenac sodium, and Indomethacin affected growth of A. castellanii. In contrast, none of the compounds tested had any effect on the viability of A. castellanii. Importantly, all NSAIDs tested abolished A. castellanii encystation. This is a significant finding as the ability of amoebae to transform into the dormant cyst form presents a significant challenge in the successful treatment of infection. The NSAIDs inhibit production of cyclo-oxegenase, which regulates the synthesis of prostaglandins suggesting that cyclooxygenases (COX-1 and COX-2) and prostaglandins play significant role(s) in Acanthamoeba biology. As NSAIDs are routinely used in the clinical practice, these findings may help design improved preventative strategies and/or of therapeutic value to improve prognosis, when used in combination with other anti-amoebic drugs.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- Department of Biological Sciences, Faculty of Science and Technology, Sunway University, Selangor, Malaysia
| | - Sahreena Lakhundi
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Junaid Iqbal
- Division of Pediatric Infectious Diseases, Vanderbilt University School of Medicine, Nashville, USA
| | - Naveed Ahmed Khan
- Department of Biological Sciences, Faculty of Science and Technology, Sunway University, Selangor, Malaysia.
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Lakhundi S, Siddiqui R, Khan NA. Cellulose degradation: a therapeutic strategy in the improved treatment of Acanthamoeba infections. Parasit Vectors 2015; 8:23. [PMID: 25586209 PMCID: PMC4300153 DOI: 10.1186/s13071-015-0642-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/05/2015] [Indexed: 11/10/2022] Open
Abstract
Acanthamoeba is an opportunistic free-living amoeba that can cause blinding keratitis and fatal brain infection. Early diagnosis, followed by aggressive treatment is a pre-requisite in the successful treatment but even then the prognosis remains poor. A major drawback during the course of treatment is the ability of the amoeba to enclose itself within a shell (a process known as encystment), making it resistant to chemotherapeutic agents. As the cyst wall is partly made of cellulose, thus cellulose degradation offers a potential therapeutic strategy in the effective targeting of trophozoite encased within the cyst walls. Here, we present a comprehensive report on the structure of cellulose and cellulases, as well as known cellulose degradation mechanisms with an eye to target the Acanthamoeba cyst wall. The disruption of the cyst wall will make amoeba (concealed within) susceptible to chemotherapeutic agents, and at the very least inhibition of the excystment process will impede infection recurrence, as we bring these promising drug targets into focus so that they can be explored to their fullest.
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Affiliation(s)
- Sahreena Lakhundi
- Department of Biological and Biomedical Sciences, Aga Khan University, Stadium Road, Karachi, Pakistan.
| | - Ruqaiyyah Siddiqui
- Department of Biological and Biomedical Sciences, Aga Khan University, Stadium Road, Karachi, Pakistan.
| | - Naveed Ahmed Khan
- Department of Biological and Biomedical Sciences, Aga Khan University, Stadium Road, Karachi, Pakistan.
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Siddiqui R, Lakhundi S, Khan NA. Status of the effectiveness of contact lens solutions against keratitis-causing pathogens. Cont Lens Anterior Eye 2014; 38:34-8. [PMID: 25280981 DOI: 10.1016/j.clae.2014.09.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/22/2014] [Accepted: 09/09/2014] [Indexed: 11/24/2022]
Abstract
PURPOSE The aim of this study was to assess the antimicrobial effects of marketed contact lens disinfecting solutions. METHODS Using ISO 14729 Stand-Alone Test for disinfecting solutions, bactericidal, fungicidal and amoebicidal assays of eight different contact lens solutions including: ReNu MultiPlus, DuraPlus, Ultimate Plus, OptiFree Express, Kontex Clean, Kontex Normal, Kontex Multisol extra(+), Kontex Soak were performed. The efficacy of contact lens solutions was determined against keratitis-causing microbes, namely: Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Fusarium solani and Acanthamoeba castellanii. RESULTS The results revealed that ReNu MultiPlus, DuraPlus and OptiFree Express were effective in killing bacterial and fungal pathogens as per manufacturer's minimum recommended disinfection time. Ultimate Plus was effective against F. solani and MRSA but ineffective against P. aeruginosa, S. marcescens and S. aureus. Of concern however, is that none of the locally formulated contact lens disinfecting solutions from Pakistan, i.e., Kontex Clean, Kontex Normal, Kontex Multisol extra(+) and Kontex Soak were effective against any of the keratitis-causing organisms tested. All eight contact lens disinfecting solutions were unable to destroy Acanthamoeba cysts. CONCLUSIONS Because such ineffective contact lens disinfection solutions present a major risk to public health, these findings are of great concern to the health officials and to the manufacturers of the contact lens disinfection solutions and effective solutions are needed, along with emphasis on proper hygiene for contact lens care and special guidelines for developing countries regarding the manufacture and storage of contact lens disinfecting solutions.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Sahreena Lakhundi
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Naveed Ahmed Khan
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan.
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Lakhundi S, Khan NA, Siddiqui R. The effect of environmental and physiological conditions on excystation of Acanthamoeba castellanii belonging to the T4 genotype. Parasitol Res 2014; 113:2809-16. [DOI: 10.1007/s00436-014-3941-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/01/2014] [Indexed: 11/28/2022]
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Lakhundi S, Khan NA, Siddiqui R. Inefficacy of marketed contact lens disinfection solutions against keratitis-causing Acanthamoeba castellanii belonging to the T4 genotype. Exp Parasitol 2014; 141:122-8. [PMID: 24657584 DOI: 10.1016/j.exppara.2014.03.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 03/07/2014] [Accepted: 03/12/2014] [Indexed: 11/17/2022]
Abstract
The aim of this study was to assess the anti-amoebic effects of marketed contact lens disinfecting solutions. Using amoebistatic, amoebicidal, and cysticidal assays, nine different contact lens solutions were tested including: ReNu MultiPlus, DuraPlus, Ultimate Plus, OptiFree Replenish, OptiFree Express, Kontex Clean, Kontex Normal, Kontex Multisol extra+, Kontex Soak. In vitro growth inhibition (amoebistatic) assays were performed by incubating Acanthamoeba castellanii with aforementioned contact lens disinfection solutions as per manufacturer's instructions in the growth medium for up to 48h at 30°C. To determine amoebicidal and cysticidal effects, amoebae were incubated with contact lens solutions in phosphate buffered saline for 24h and viability was determined by haemocytometer counting as well as re-inoculating them in the growth medium. For controls, solutions were tested against bacterial corneal pathogen, Pseudomonas aeruginosa, as well as amoebae were incubated with the solvent alone. Of the nine contact lens solutions tested, none of them showed potent amoebicidal effects. Only DuraPlus and OptiFree Replenish exhibited trophozoite lysis of 85.3% and 73.7% respectively. In contrast, all contact lens disinfection solutions except Kontex Clean, Kontex Normal, Kontex Multisol extra+, tested showed amoebistatic effects. Importantly, none of the contact lens disinfection solutions exhibited cysticidal effects using qualitative assays, i.e., cysts treated with aforementioned solutions re-emerged as viable amoebae upon inoculation in the growth medium. However, more than 3-log reduction was observed when ReNu MultiPlus, DuraPlus and OptiFree Express were tested against P. aeruginosa which is in accordance with the ISO Stand-Alone Primary acceptance criteria. These findings are of great concern for contact lens users.
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Affiliation(s)
- Sahreena Lakhundi
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Naveed Ahmed Khan
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - Ruqaiyyah Siddiqui
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan.
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Siddiqui R, Chaudhry T, Lakhundi S, Ahmad K, Khan NA. Failure of chemotherapy in the first reported cases of Acanthamoeba keratitis in Pakistan. Pathog Glob Health 2014; 108:49-52. [PMID: 24548160 DOI: 10.1179/2047773213y.0000000124] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Acanthamoeba keratitis is a painful and progressive infection of the cornea that can result in loss of vision. Here, for the first time in Pakistan, we report two cases of Acanthamoeba keratitis. The first patient was a 37-year-old female who presented with severe itching, redness, pain, along with loss of vision. The patient was a regular soft contact lens wearer. The second patient was a 25-year-old female who had been using soft contact lenses for the past two years. She presented with a burning sensation and extreme pain, along with loss of vision. Both patients were treated for a possible microbial keratitis with topical moxifloxacin hydrochloride drops, vancomycin drops, propamidine isethionate ointment, amphotericin B drops, and amikacin drops. However, the response was inadequate and both patients were referred for corneal transplant. Acanthamoeba castellanii was isolated by placing contact lenses and contact lens cases on non-nutrient agar plates containing a lawn of non-invasive Escherichia coli K-12 HB101 bacteria. The polymerase chain reaction (PCR) using genus-specific probes confirmed the identity of Acanthamoeba spp., whereas the morphological characteristics of trophozoites and cysts were suggestive of A. castellanii in both cases. With growing use of contact lenses for vision correction/cosmetic use coupled with sub-standard lens care in this region and the possibility of non-contact lens-associated Acanthamoeba keratitis, a need for increased awareness of this sight-threatening infection is discussed further.
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