Isolation and characterization of acinetobacter baumannii recovered from campylobacter selective medium
Citation
Fernando, D.M., Khan, I.U.H., Patidar, R., Lapen, D.R., Talbot, G., Topp, E., Kumar, A. (2016). Isolation and characterization of acinetobacter baumannii recovered from campylobacter selective medium. Frontiers in Microbiology, [online] 7(NOV), http://dx.doi.org/10.3389/fmicb.2016.01871
Plain language summary
Acinetobacter baumannii is a bacterial pathogen primarily associated with hospital-acquired infections especially to immunocompromised patients. Due to extensive antibiotic resistance problem, this pathogen has been considered as one of the organisms threatening the current antibiotic era. Since Acinetobacter spp. are strict aerobe, so the interesting aspect of this study was the recovery of A. baumannii and A. indicus from agricultural water and dairy cattle manure storage tank under microaerophilic conditions on a growth media containing antimicrobial supplements selective for the isolation of Campylobacter spp. The strains were tested for the antibiotic resistance and genotypically characterized and compared with clinical isolates to identify the source of contamination. The results showed that the strains were less sensitive to the antibiotics prescribed by the physicians against Acinetobacter infection. Similarly, A. baumannii strains showed high degree of diversity with each other as well as with clinical isolates. The study results show the prevalence and versatility of this important pathogen in various environmental niches and growth conditions and thus opens further research avenues to study its adaptability to environment and resistance to antibiotics.
Abstract
Acinetobacter baumannii, a Gram-negative opportunistic pathogen, is known to cause multidrug resistant infections. This organism has primarily been isolated from clinical environments and its environmental reservoirs remain largely unknown. In the present study, we recovered seven isolates of A. baumannii growing under conditions selective for Campylobacter spp. (microaerophilic at 42°C and in the presence of antibiotics) from dairy cattle manure storage tank or surface water impacted by livestock effluents. Antibiotic susceptibility tests revealed that all of these isolates were less susceptible to at least two different clinically relevant antibiotics, compared to the type strain A. baumannii ATCC17978. Expression of resistance-nodulation-division efflux pumps, an important mechanism of intrinsic resistance in these organisms, was analyzed, and adeB was found to be overexpressed in one and adeJ was overexpressed in three isolates. Comparison of these isolates using genomic DNA Macro-Restriction Fragment Pattern Analysis (MRFPA) revealed relatively low relatedness among themselves or with some of the clinical isolates from previous studies. This study suggests that A. baumannii isolates are capable of growing under selective conditions for Campylobacter spp. and that this organism can be present in manure and water.