Contents lists available at ScienceDirect Contact Lens and Anterior Eye journal homepage: www.elsevier.com/locate/clae Identification of virulence factors in contact lens associated bacteria: A physiological approach Iram Liaqat a , Qurat-ul-Ain Saleem b , Hafiz Muhammad Tahir a , Muhammad Arshad c , Najma Arshad b, ⁎ a Department of Zoology, Govt. College University, Lahore, Pakistan b Department of Zoology, University of the Punjab, Quaid-e-Azam campus Lahore, Pakistan c Department of Zoology, University of Education, Lahore, Pakistan ARTICLE INFO Keywords: Contact lens Pathogenic potential Contamination Antibiotic resistance Virulence markers ABSTRACT Purpose: Wearing contact lens requires awareness about possible contaminants, the causative agents of multiple complications. The present study focused on identification of potential pathogens and presence of virulence associated markers in contact lens associated bacteria. Methods: Bacterial contaminants were isolated from contact lenses or cleaning solutions collected from University students. Isolates were identified using conventional methods followed by 16S rRNA gene sequencing and screened for the presence of virulence factors which included capsular presence, adhesion, serum resistance, iron chelation, haemagglutination and hemolysis. Moreover, antibiotic resistance profile was also monitored. Results: Contamination was observed in 79% (45 of 57) of lenses. Based on 16S rRNA sequencing Bacillus sp. was found to be most abundant (26%). The presence of at least three pathogenic characteristics was recorded in 75.8% isolates. Among the pathogenic characteristics, capsule presence was found to be the most prevalent character (73%) followed by hemolysin production (65%), serum resistance (61%), haemagglutination (56%), iron chelation (50%) and polystyrene adherence (42%). Multiple antibiotic resistance was recorded in 66.13% isolates. Cluster analysis on the basis of virulence markers separated all isolates in two groups. Potential pa- thogens and non-pathogens were found to be equally frequent among contaminants of contact lens cases. Conclusion: The present work provides evidence that pathogenic bacteria can adhere and survive in contact lens or lens solution. It highlights the need for the development of new methods to protect contact lenses and lens care accessories. Drugs targeting capsule formation may offer a good option for treatment or use in cleaning solution. 1. Introduction Contact lenses are successfullyused for vision correction along with cosmetics. The number of contact lens user has exceeded to 140 million worldwide [1]. In spite of advantages for users, certain risks have been associated with them. Two key problems including discomfort with lenses and infection during wear, both of which impose challenges to the lens industry. Comfort may be being resolved by continuous im- provement in lens material. However, the issue of microbial con- tamination needs to be studied in detail for improvement in the pre- vious practices and the design of new strategies to fight with potential pathogens. Microbial lens contaminants include multiple potential pa- thogens along with nonpathogenic organisms [2]. Eye inflammation, ulcerative keratitis and corneal infection are reported to be associated with contact lenses. Gram-negative bacteria are commonly considered causative agents of adverse responses during contact lens wear [2]. Lens biomaterial acts as a vector for microbial adherence and sub- sequent transfer to the ocular surface. Lens deposits or defects, hypoxia, cytotoxicity of care solutions, changes in pH and oxygen, CO 2 con- centration, and corneal surface disruption are among the major risk factor, for causing eye inflammation [3–6]. Its treatment may range from not wearing your contact lenses for a short span of time to in- tensive antibiotic treatment of infections and expensive with variable results. The occurrence of contact lens related complications is rare, but if severe, could lead to permanent vision loss. Pathogens are dis- tinguished from non-pathogenic relatives due to the presence of some unique virulence factors. Adherence, iron chelation, hemolysin pro- duction are reported more frequently in pathogenic bacteria. Adherence https://doi.org/10.1016/j.clae.2018.10.002 Received 1 January 2018; Received in revised form 7 June 2018; Accepted 10 October 2018 ⁎ Corresponding author at: Department of Zoology, University of the Punjab, 54590, Lahore, Pakistan. E-mail addresses: dr.iramliaqat@gcu.edu.pk (I. Liaqat), najmaarshad.zool@pu.edu.pu (N. Arshad). Contact Lens and Anterior Eye xxx (xxxx) xxx–xxx 1367-0484/ © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved. Please cite this article as: Liaqat, I., Contact Lens and Anterior Eye, https://doi.org/10.1016/j.clae.2018.10.002