Grduate student Chithra Muraleedharan is awarded travel grant

Department of Biological Sciences graduate student Chithra Muraleedharan has been selected to receive an American Society of Microbiology Student Travel Grant to assist in covering expenses when she attends the 2012 Interscience Conference on Antimicrobial Agents and Chemotherapy. The ICAAC 2012, which will be held in San Francisco during September, is a leading international conference on antimicrobial agents and infectious diseases. Muraleedharan works in the laboratory of Associate Professor Satish Walia, of the Department of Biological Sciences. She will be busy this summer, because she also is lead author on an abstract to be presented at the 2012 Society of Industrial Microbiology and Biotechnology meeting in Washington DC this August. Coauthors include graduate student Natasha Bhutani and undergraduate engineering biology major Sandra Mikhail.

P111: Diversity among Cefotaxime-Resistant Bacteria and Detection of CTX-M-type Extended Spectrum Beta-Lactamase Genes in Pharmaceutical and Personal Care Products Contaminated Sediments of Clinton River in Michigan
Chithra Muraleedharan¹, Natasha Bhutanin¹, Sandra Mikhailn¹, Manhar Sawanin², Ashok Kumarn³ and Satish K. Walian¹,
(1)Biological Sciences, Oakland University, Rochester, MI, (2)Microbiology, Crittenton Hospital, Rochester, MI, (3)Kresge Eye Institute, Wayne State University, Detroit, MI
Anthropogenic chemicals of emerging concerns (CEC) have been detected in river waters and sediments and could be responsible for selection of resistant bacteria. The objective of this study is to assess the presence of extended-spectrum beta-lactamase (ESBL) genes in the Clinton River, the main branch of which flows into the Great Lakes water system. The river water and sediments samples were collected and processed. Bacterial isolates were identified using Phoenix BD Systems and confirmed by 16S rRNA sequence analysis. Both human and fish pathogens (Salmonella typhimurium, Shigella dysenteriae, Klebsiella pneumoniae, Aeromonas sobria, Aeromonas caviae, Aeromonas veronii, Yersinia ruckeri, and Pseudomonas cepacia) were identified. Antibiotic susceptibilities of the bacteria were determined by the Kirby-Bauer disc diffusion test. Of a total of 136 bacterial isolates tested for antibiotic susceptibility, 39% were resistant to cefotaxime (CTX) (6% were ESBL producers), 38% to chloramphenicol (CHL), 17% to tetracycline (TET), 15% to ciprofloxacin (CIP) and 13% to gentamicin (GEN). Multidrug resistance was prevalent with common resistance patterns of CTX TET CHL GEN CIP (0.74%), CTX CHL GEN CIP (1.47%) and CTX TET CHL (6.62%). All of the eight ESBL-positive bacteria amplified for the blaCTX-M-1 gene. The presence of bacteria resistant to third and fourth generation cephalosporins in the water and sediments of urban Clinton River is worrisome, since this could be a reservoir for the dissemination of resistant human and fish pathogens to the Great Lakes water system that is a major source of drinking water for the population living in Canada and USA.

Two other abstracts from Walia’s group will also be presented, including

P109: Pharmaceuticals and Personal Care Products and PCBs Contaminated Environments Contain Opportunistic Bacterial Pathogens with Multidrug Resistance Genes
Sandeep K. Walia¹, Natasha Bhutani², Chithra Muraleedharan², Sonia Rana³, Abdul Abdul² and Satish Walia²
(1)Internal Medicine, Henry Ford Hospital, Detroit, MI, (2)Biological Sciences, Oakland University, Rochester, MI, (3)Opthalmology, Kresge Eye Institute, Detroit, MI
The purpose of this study was to assess the presence of multidrug resistant (MDR) heterotrophic bacteria in anthropogenic chemicals contaminated urban river sediments and industrial sites. Pharmaceutical and personal care products (PPCP) and PCB contaminated river sediments, soil and groundwater samples collected from the Detroit area in MI and in Syracuse, NY were studied for the presence of MDR opportunistic bacterial pathogens, which also have PCB- degrading capabilities. The PCB-degrading bacteria from the soil-groundwater system demonstrated 100 % biotransformation of 3,5-dichlorobiphenyl and up to 54% biotransformation of 2,2’,3,3’5,6,6’-heptachlorobiphenyl. Known opportunistic pathogens were identified in all of the river sediment and soil-water samples tested. The antibiotic susceptibility assays were performed on bacterial isolates against 8 antibiotics. The results showed that the PCB-degrading bacteria were resistant to six clinically effective antibiotic classes: cephalosporins, carbapenems, quinolones, aminoglycosides, chloramphenicol and tetracycline. Thirteen out of 17 (76%) PCB-degrading bacteria were found to be resistant to a combination of 3 or more antibiotics. The urban river sediment contained CTX-M-type extended-spectrum beta-lactamase genes. The findings from this study indicate that MDR bacteria are not only prevalent in clinical bacteria, but they are also present in river sediments, soil and groundwater at urban and industrial sites, which are contaminated with anthropogenic chemicals. The environmental implication is significant, in that risk assessments at PCB-contaminated sites do not consider health and environmental risks associated with the presence of MDR bacteria.

P131: Antibiotic Resistant Bacteria in Soil, Sediments, and Runoff from a Soybean Farm
Kevin F. Cumper, Natasha Bhutani, Abdul S. Abdul and Satish K. Walia
Biological Sciences, Oakland University, Rochester, MI
The purpose of this study was to compare the antibiotic resistances (ABR) in bacterial isolates in active soybean farm soil and runoff exposed to fertilizers, pesticides and herbicides. The samples were selected to represent a control group of untreated soil, active farm soil exposed to agricultural chemicals, and sediment and runoff beyond the cultivated farm. Similar viable bacteria counts (106 CFU/g) were found in the farmland soil samples and in untreated soil (107 CFU/g). Bacterial isolates from the samples were tested for minimum inhibitory concentrations of antibiotic resistance using agar dilution methods and were then screened for ABR and integron genes using standard PCR protocols. The results indicated that bacteria within the soil/water/sediment population were resistant to individual and combinations of antibiotics used for the treatment of human infections. The most prevalent ABR in 180 Gram-negative bacteria were ampicillin (AMP) 85%, followed by chloramphenicol (CHL) 76%, gentamicin (GEN) 9%, tetracycline (TET) 7% and ciprofloxacin (CIP) 3% of the isolates. Of 165 Gram-positive isolates, 32% showed resistance to AMP, erythromycin (ERM) and vancomycin (VAN), 20% to CHL, 6% to GEN, 4% to TET and 1% to CIP. The presence of int1 in the soil indicates a possible mechanism for ABR gene transfer in agricultural soil, although vanA and vanB were not detected. The findings from this study indicate the potential for the development of resistant bacteria under typical farming conditions of exposure to chemical treatments, which impact crop yields and can potentially impact human health, welfare and the environment.