Volume: 56 Issue: 4
Year: 2025, Page: 572-577, Doi: https://doi.org/10.51966/jvas.2025.56.4.572-577
Received: July 23, 2025 Accepted: Sept. 20, 2025 Published: Dec. 31, 2025
Acinetobacter baumannii is a critical opportunistic pathogen known for its extensive antibiotic resistance. This study was conducted to characterise quinolone-resistant A. baumannii for key genetic markers. From a screening of 450 samples, a total of 32 isolates confirmed as A. baumannii by PCR targeting the bfmR gene. Seven of these isolates were found to be phenotypically resistant to quinolones and were selected for further molecular analysis. A three-primer mismatch amplification mutation assay (MAMA) PCR was employed to detect resistance-conferring mutations in the gyrA (S81L) and parC (S84L) genes. All seven isolates showed phenotypic resistance to ciprofloxacin, gatifloxacin and enrofloxacin. The MAMA-PCR results, validated by Sanger sequencing, indicated that six of the seven isolates harboured mutations in gyrA and five of these also possessed a mutation in parC, correlating with the observed phenotypic resistance. The MAMA-PCR provides a rapid and efficient method for screening genetic markers of resistance, which can be valuable for epidemiological surveillance.
Keywords: Acinetobacter baumannii, MAMA-PCR, quinolone resistance, bfmR, gyrA, parC
Alcock, B.P., Raphenya, A.R., Lau, T.T.Y., Tsang, K.K., Bouchard, M., Edalatmand, A., Hu, W., van Essen, A., Oloni, M., Pu, F., Abe, F., Carkonen, K.A., Wassenaar, T.M., Gannon, B., Mubareka, S., Topp, E., Taboada, E.N., Hsiao, W.W.L., Brinkman, F.S.L. and McArthur, A.G. 2023. CARD 2023: expanded curation, support for machine learning and Resistomes and Variants. Nucleic Acids Res. 51(D1): D691-D699.
Ananya, M.S.V.B., Mathew, B., Sunil, B., Sethulekshmi, C., Vijay, D. and Bunglavan, S.J. 2025. Occurrence of Klebsiella pneumoniae in the soil samples of selected dairy farms in Thrissur, Kerala. J. Vet. Anim. Sci. 56(1): 136-140.
Ashtamy, M.G., Mani, B.K., Mini, M., Ambily, R. and Anoop, S. 2023. Assessment of quinolone resistance in bacteria isolated from corneal ulcers in dogs. J. Vet. Anim. Sci. 54(1): 275-278.
Asif, M.H., Latha, C., Menon, K.V., Jolly, D., Nair, S.N. and Sunanda, C. 2020. The occurrence of antibiotic residues in pooled raw cow milk samples of Palakkad, Kerala. J. Vet. Anim. Sci. 51(1): 34-39.
CLSI [Clinical and Laboratory Standards Institute]. 2020. Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated From Animals. (5th Ed.). Clinical and Laboratory Standards Institute supplement VET01S. Wayne, PA. 250p.
CLSI [Clinical and Laboratory Standards Institute]. 2025. Performance Standards for Antimicrobial Susceptibility Testing. (35th Ed.). Clinical and Laboratory Standards Institute supplement M100. Wayne, PA. 428p.
Hamouda, A., Amyes, S.G.B. and Young, H.K. 2010. Quinolone resistance in Acinetobacter baumannii. J. Med. Microbiol. 59(4): 493-494.
Hooper, D.C. 2001. Mechanisms of action of antimicrobials: focus on fluoroquinolones. Clin. Infect. Dis. 32(Suppl 1): S9-S15.
Hujer, K.M., Hujer, A.M., Hulten, E.A., Bajaksouzian, S., Adams, J.M., Donskey, C.J., Ecker, D.J., Massire, C., Eshoo, M.W., Sampath, R., Thomson, J.M., Rather, P.N. and Bonomo, R.A. 2009. Analysis of antibiotic resistance genes in multidrug-resistant Acinetobacter sp. isolates from military and civilian patients. Antimicrob. Agents Chemother. 53(6): 2499-2508.
Jawad, A., Hawkey, P.M., Heritage, J. and Snelling, A.M. 1994. Description of Leeds Acinetobacter Medium, a new selective and differential medium for isolation of Acinetobacter baumannii. J. Clin. Microbiol. 32(10): 2353-2357.
Lee, C.R., Lee,J.H., Park, M., Park, K.S., Bae, I.K., Kim, Y.B., Kim, C.B., Jeong, B.C. and Lee, S.H. 2017. Biology of Acinetobacter baumannii: pathogenesis, antibiotic resistance mechanisms and prospective treatment options. Front. Cell. Infect. Microbiol. 7: 55.
Lin, M.F. and Lan, C.Y. 2014. Antimicrobial resistance in Acinetobacter baumannii: From bench to bedside. World J. Clin. Cases 2(12): 787-814.
Munoz-Price, L.S. and Weinstein, R.A. 2008. Acinetobacter infection. N. Engl. J. Med. 358(12): 1271-1281.
Peleg, A.Y., Seifert, H. and Paterson, D.L. 2008. Acinetobacter baumannii: emergence of a successful pathogen. Clin. Microbiol. Rev. 21(3): 538-582.
Perez, F., Hujer, A.M., Hujer, K.M., Decker, B.K., Rather, P.N. and Bonomo, R.A. 2007. Global challenge of multidrug-resistant Acinetobacter baumannii. Antimicrob. Agents Chemother. 51(10): 3471-3484.
Quinn, P.J., Markey, B.K., Carter, M.E., Donnelly, W.J.C. and Leonard, F.C. 2002. Veterinary Microbiology and Microbial Disease. Blackwell Science, Oxford, 536p.
Sambrook, J. and Russell, D.W. 2001. Molecular Cloning: A Laboratory Manual. 3rd Ed. Cold Spring Harbor Laboratory Press, New York, 2344p.
Tomaras, A.P., Flagler, M.J., Dorsey, C.W., Gaddy, J.A. and Actis, L.A. 2008. Characterization of a two-component regulatory system from Acinetobacter baumannii that controls biofilm formation and attachment to human epithelial cells. Microbiology 154(11): 3398-3409.
Vila, J., Ruiz, J., Goni, P. and Jimenez de Anta, T. 1996. Detection of mutations in the parC gene of ciprofloxacin-resistant clinical isolates of Escherichia coli. Antimicrob. Agents Chemother. 40(2): 491-493.
Whitman, W.B., Rainey, F., Kampfer, P., Trujillo, M., Chun, J., DeVos, P., Hedlund, B. and Dedysh, S. (eds.). 2015. Bergey's Manual of Systematics of Archaea and Bacteria. John Wiley and Sons, Inc., Hoboken, NJ.
© 2025 Hebbal et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Hebbal, A.M., Mathew, B., Sunil, B., Sethulekshmi, C., Radhika, G., Justin Davis, K. and Sivaraman, G.K. 2025. Validation of a mismatch amplification mutation assay (MAMA) PCR for the rapid detection of quinolone resistanceconferring mutations in the gyrA and parC genes of Acinetobacter baumannii. J. Vet. Anim. Sci. 56 (4): 572-577