Serotypes, virulence factors and antimicrobial susceptibility of vaginal and fecal

32 Although Escherichia coli (E. coli) typically colonize the intestinal tract and vagina 33 of the giant pandas, it has caused enteric and systemic disease in the giant pandas 34 and greatly impact the health and survival of this endangered species. In order to 35 understand the distribution and characteristics of E. coli from giant pandas, 67 fecal 36 and 30 vaginal E. coli isolates from 21 giant pandas were characterized for O 37 serogroups, phylogenetic group, antimicrobial susceptibility, and PFGE profiles. In 38 addition, these isolates were tested for the presence of extraintestinal pathogenic E. 39 coli (ExPEC) and diarrheagenic E. coli (DEC) by multiplex PCR detection of 40 specific virulence genes. The most prevalent serogroups in all E. coli isolates were 41 O88, O18, O167, O4 and O158. ExPEC mostly were detected in vaginal isolates and 42 DEC only detected in fecal isolates. Phylogenetic group B1 predominated in fecal 43 isolates, while groups B2 and D were frequently detected in vaginal isolates. 44 Resistance was most frequently observed to trimethoprim/sulfamethoxazole, 45 followed by nalidixic acid, tetracycline. All except five isolates were typeable using 46 XbaI and were categorized into 74 PFGE patterns. Our findings indicate that panda E. 47 coli isolates exhibited antimicrobial resistance and potentially pathogenic E. coli 48 were present in giant pandas. In addition, these E. coli isolates were genetically 49 diverse. This study may provide helpful information for developing strategies in the 50 future to control E. coli infections in the giant panda. 51