Molecular Detection of Some A.hydrophila Toxins and its Antibiotics Resistance Pattern Isolated From Chicken Feces in Thi-Qar Province (Iraq)

Abstract

The high isolation rate of virulent A.hydrophila from chicken represent an important public health concern especially when these bacteria exhibit increased antimicrobial resistance to medically important antibiotics, so this study was conducted to isolate A.hydrophila from chicken feces and investigate the presence of some toxins genes and determine their antibiotics resistance profile. Chicken feces were collected from different regions, throughout Thi-Qar province south of Iraq, in period extended from July 2015 to January 2016. A.hydrophila isolates were identified by morphological, biochemical and API20E. These isolated were subjected to PCR assay for confirmation, targeting 16S RNA-23SRNA Intergenic Spacers Region and for detection of important virulence genes including hemolytic toxin Aerolysin (Aero), Heat labile enterotoxin (Alt) and Heat stable enterotoxin (Ast). Twelve A.hydrophial were isolated and identified to species level among 23 Aeromonas spp isolated from chicken fecal samples with overall incidence rate (52.6%). Screening for virulence genes revealed that 10/12 (83.4%) were positive for Aerolysin ( Aero) gene and 9/12( 75%) for Heat labile enterotoxin (Alt ) gene, while none of these isolates were positive for Heat stable enterotoxin (Ast) gene 0/12(0%).The most prevalent genotype was (Aer+ Alt+ Ast_). Antibiogram against 19 antibiotics revealed that, all isolates in showed absolute susceptibility(100%) to Gentamycin, Oflaxacin, Amikacin, Norfloxacin, Imipnem Ciprofloacin. However, multidrug resistance recorded in all isolates, 2 isolates (16.7%) were resistant to eight antibiotics including , Clindamycin, Cephalothin , Vancomycin, Ticacillin-clavulnoc acid, Ceftazidime, Cefoxitin, Trimethoprim-sulfamethaxazon, Azithromycin ,with multidrug resistance index (0.42) , and 5/12 (41.7%) were resistance to seven antibiotics (58.4%) with MDRI( 0.36), four isolates( 33.4%) were resistant to six antibiotics with MDRI ( 0.31), while only one isolates 1/12(8.4%) were resistant to five antibiotic with MDRI (0.26). The present study showed that detection of pathogenic A.hydrophila harboring important virulence genes Aerolysin and Alt with resistance to many clinically important antibiotics is a good indication that chicken feces constitute important source for pathogenic Ahydrophila infecting human that come in contact with chicken and spread of multidrug resistance organisms in environment .