Antibiotic resistant strains number of antibiotic

Info icon This preview shows pages 7–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Summary of Antibiotic Inactivation Studies for Gram-Negative Isolates. Antibiotic Resistant Strains Number of antibiotic Inactivation Strains Mechanism of Inactivation Apramycin 10 0 ------- Gentamicin 11 0 ------- Neomycin 24 0 ------- Streptomycin 30 0 ------- Telithromycin 17 0 ------- Clindamycin 39 0 ------- Chloramphenicol 28 2 Acetylation Trimethoprim 35 0 ------- Cephalexin 36 14 Hydrolysis Cefotaxime 12 4 Hydrolysis Ampicillin 30 13 Hydrolysis Piperacillin 30 16 Hydrolysis Strains were grown in 50% TSB for 5 days in presence of 20 m g/ml antibiotic. Conditional media was used for setting up disk diffusion assays and LC-MS analyses. Inactivation was defined as the absence of a zone of clearance around the disk. Hydrolytic mechanism of ß-lactam resistance is inferred. doi:10.1371/journal.pone.0034953.t002 Figure 6. Genetic context of mph genes in Brachybacterium strains. A genetic map was constructed using available genome sequences of Brachybacterium strains and shown above is a schematic of translated protein query based on BLAST analysis. The MPH sequence is shown in red and homologous sequences are marked with identical colors. doi:10.1371/journal.pone.0034953.g006 Antibiotic Resistance in Cave Bacteria PLoS ONE | 7 April 2012 | Volume 7 | Issue 4 | e34953
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
actinomycetes [11]. As prodigious producers of natural products including antibiotics, it is logical that actinomycetes would also be enriched in resistance elements. Second, the isolate sample size is smaller in this study in comparison to our previous study and we have likely not examined the full resistome of both the culturable and non-culturable microbiome. Further studies of both surface and cave microbiomes including more extensive cultivation and metagenomic analysis are therfore necessary to interpret the results with more confidence. Aminoglycoside antibiotic resistance was more common in Lechuguilla Cave isolates as compared to surface actinomycetes. This may reflect the biosynthetic capacity of antibiotic producing bacteria in Lechuguilla Cave and the production of these antibiotics by species within the cave. A survey of the acti- nomycetes in our collection using oligonucleotide primers designed to amplify aminoglycoside biosynthetic genes failed to identify potential aminoglycoside producers; however linking resistance to antibiotic production will require an extensive and systematic survey of the cave microbiome and resistome that is beyond the objectives of this work. The mechanisms of antibiotic modification and inactivation are evidence of highly specific evolutionary adaptations to evade the cytotoxic action of these antibiotics. The high level of ß- lactam antibiotic resistance by hydrolysis parallels that of surface bacteria and the result of genetically diverse ß-lactamases that are widespread in microbial genomes. Similarly, chloramphenicol acetylation was also detected, an activity that is well established in surface bacterial isolates [49]. Nonetheless, the hydrolytic inactivation of daptomycin in isolates of P. lautus was unexpected.
Image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern