Graduate student Deepa Talreja wins award from the Dr. Raniyah Ramadan Foundation

Graduate student Deepa Talreja, of the Biomedical Sciences: Biological Communication PhD program, was awarded second prize in the Dr. Raniyah Ramadan Foundation Young Investigator Award in Microbiology competition. The award arises from an abstract Talreja submitted at the ARVO 2013 annual meeting. The Dr. Raniyah Ramadan Foundation is a nonprofit organization that promotes higher education and research in the biomedical sciences. The Association for Research in Vision and Ophthalmology (ARVO), established in 1928, encourages and assists research, training, publication, and dissemination of knowledge in vision and ophthalmology. The award will be announced at the ARVO 2014 annual meeting in Orlando. Talreja works in the laboratory of Associate Professor Satish Walia.

The award-winning abstract, presented at the ARVO 2013 meeting in Seattle, Washington (May 5-9, 2013) is reproduced below. Coauthor on the abstract is graduate student Chithra Muraleedharan.

Program Number: 2903 Poster Board Number: B0272 Presentation Time: 8:30 AM - 10:15  AM

Antibiotic resistance and molecular characterization of ocular isolates of Acinetobacter baumanniii

Deepa Talreja^{1, 2}, Chithra Muraleedharan², Keith Kaye³, Satish K. Walia², Ashok Kumar^{1, 4}.

¹Ophthalmology, Kresge Eye Institute, Detroit, MI;
²Biological Sciences, Oakland University, Auburn Hills, MI;
³Internal Medicine, Detroit Medical Center, Wayne State University, Detroit, MI;
⁴Anatomy and Cell Biology, Wayne State University, Detroit, MI.

Purpose: Acinetobacter baumannii is an opportunistic pathogen that most frequently causes nosocomial infections. Although few clinical studies have documented A. baumannii as a causative agent of keratitis and endophthalmitis, the detailed characterization of ocular isolates remains to be determined. In this study, we assessed the antibiotic-resistant pattern, genetic relatedness and plasmid profiles of ocular isolates from South East Michigan.

Methods: Ocular A. baumannii isolates (n=12) were taken from the clinical microbiology laboratory of Detroit Medical Center. The minimum inhibitory concentration (MIC) of various antibiotics was determined against each isolate using Micro scan. Plasmid profiling and conjugation experiments were carried out to determine the transfer of antibiotic resistant genes. PFGE was performed to determine the clonal relatedness of various isolates. RT-PCR was used to check the expression of virulence genes (omp A, bap, PholC and PholD). Biofilm assay was carried out in a 96 well plate using crystal violet. The cytotoxicity, internalization and adherence assay was performed on immortalized human corneal epithelial cell line(HCEC).

Results: Majority of the isolates were multidrug resistant. However, none of them were β-lactamase producers. All isolates harbored multiple plasmids and ten distinct plasmid profiles were observed. Multiple antibiotic resistance genes transferred from donor resistant bacteria to recipient E. coli. J53. PFGE analysis of Apa I-digested genomic DNA showed the presence of distinct genotypes among all isolates. Biofilm formation assay revealed that 10 isolates were strong and two were moderate biofilm producers. Moreover, all isolates induced cytotoxicity and showed strong affinity towards adherence and internalization in HCECs. Virulence genes ompA and bap were constitutively expressed whereas the expression of PholC and PholD varied among the isolates.

Conclusions: This study highlights an importance of A. baumannii as a potential ocular pathogen which can cause aggressive infections in the eye. Considering the highly resistant nature and their presence on ocular surface warrants further investigation to assess the pathogenesis of A. baumannii ocular infections.

Walia notes that “A. baumannii is an emerging nosocomial pathogen and is reported to cause serious bacterial infections to immunocompromised  including pneumonia, endophthalmitis. This organism is inheritanly resistant to multiple antibiotics, is slow grower and difficult to treat.  Its pathogenesis in human infections including ocular infection is not well understood. Deepa's work  is presently under review in peer-reviewed journal. I am pleased with Deepa's presentation and quality of research  is justifiably recognized by ARVO refrees. Deepa's research recognition at the international platform is a testimony to high quality of research and doctoral training to Oakland University students. We are thankful for the partial financial support from CBR and constant encouragement from Dr. Arik Dvir, Chair , Biological Sciences, OU." Talreja  adds “I am thankful to my mentors Dr. Kumar (WSU) and Dr. Satish K Walia (Oakland University) for their constant encouragement and Dr. Keith S Kaye (WSU, Internal Medicine) for providing access to ocular A. baumannii isolates”.