Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Apr 23;20(1):27.
doi: 10.1186/s12941-021-00435-w.

Antibiotic resistance pattern of Bacteroides fragilis isolated from clinical and colorectal specimens

Seyedesomaye Jasemi  1 , Mohammad Emaneini  1 , Zahra Ahmadinejad  2 , Mohammad Sadegh Fazeli  3 , Leonardo A Sechi  4 , Fatemah Sadeghpour Heravi  5 , Mohammad Mehdi Feizabadi  6   7
Affiliations

Antibiotic resistance pattern of Bacteroides fragilis isolated from clinical and colorectal specimens

Seyedesomaye Jasemi et al. Ann Clin Microbiol Antimicrob. .

Abstract

Background: Bacteroides fragilis is a part of the normal gastrointestinal flora, but it is also the most common anaerobic bacteria causing the infection. It is highly resistant to antibiotics and contains abundant antibiotic resistance mechanisms.

Methods: The antibiotic resistance pattern of 78 isolates of B. fragilis (22 strains from clinical samples and 56 strains from the colorectal tissue) was investigated using agar dilution method. The gene encoding Bacteroides fargilis toxin bft, and antibiotic resistance genes were targeted by PCR assay.

Results: The highest rate of resistance was observed for penicillin G (100%) followed by tetracycline (74.4%), clindamycin (41%) and cefoxitin (38.5%). Only a single isolate showed resistance to imipenem which contained cfiA and IS1186 genes. All isolates were susceptible to metronidazole. Accordingly, tetQ (87.2%), cepA (73.1%) and ermF (64.1%) were the most abundant antibiotic-resistant genes identified in this study. MIC values for penicillin, cefoxitin and clindamycin were significantly different among isolates with the cepA, cfxA and ermF in compare with those lacking such genes. In addition, 22.7 and 17.8% of clinical and GIT isolates had the bft gene, respectively.

Conclusions: The finding of this study shows that metronidazole is highly in vitro active agent against all of B. fragilis isolates and remain the first-line antimicrobial for empirical therapy.

Keywords: Antibiotic resistance; Bacteroides fragilis; Resistance gene; bft gene.

PubMed Disclaimer

Conflict of interest statement

All authors declare that they have no conflict of interest.

Figures

Fig. 1
Fig. 1
Clinical sample frequency according to clinical sample type
Fig. 2
Fig. 2
MIC values of (a) Penicillin, b Cefoxitin and c Clindamycin with the presence of the cepA gene, cfxA gene and ermF genes in B. fragilis
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Wexler HM. Bacteroides: the Good, the Bad, and the Nitty-Gritty. Clin Microbiol Rev. 2007 doi: 10.1128/cmr.00008-07. - DOI - PMC - PubMed
    1. Yamamoto T, Ugai H, Nakayama-Imaohji H, Tada A, Elahi M, Houchi H, et al. Characterization of a recombinant Bacteroides fragilis sialidase expressed in Escherichia coli. Anaerobe. 2018 doi: 10.1016/j.anaerobe.2018.02.003. - DOI - PubMed
    1. Jeverica S, Sóki J, Premru MM, Nagy E, Papst L. High prevalence of division II (cfiA positive) isolates among blood stream Bacteroides fragilis in Slovenia as determined by MALDI-TOF MS. Anaerobe. 2019 doi: 10.1016/j.anaerobe.2019.01.011. - DOI - PubMed
    1. Yekani M, Baghi HB, Naghili B, Vahed SZ, Sóki J, Memar MY. To resist and persist: Important factors in the pathogenesis of Bacteroides fragilis. Microb Pathog. 2020 doi: 10.1016/j.micpath.2020.104506. - DOI - PubMed
    1. Buckwold SL, Shoemaker NB, Sears CL, Franco AA. Identification and characterization of conjugative transposons CTn86 and CTn9343 in Bacteroides fragilis strains. Appl Environ Microbiol. 2007 doi: 10.1128/AEM.01669-06. - DOI - PMC - PubMed

MeSH terms