Genotypic Diversity and Multidrug Resistance Profiles of AmpC-Producing Escherichia coli and Klebsiella pneumoniae in Abakaliki, Nigeria
Abstract
Background: This study investigated the genotypic diversity and multidrug resistance profiles of plasmid-mediated AmpC (pAmpC)-producing Escherichia coli and Klebsiella pneumoniae isolated from clinical samples at AE-FUTHA, Nigeria.
Methods: A total of 200 clinical samples (140 urine and 60 wound swabs) were collected from patients at AE-FUTHA. Phenotypic detection of AmpC β-lactamases was performed using the cefoxitin-cloxacillin double-disk synergy test (CC-DDST). All phenotypically confirmed AmpC-producing isolates were subjected to antimicrobial susceptibility testing using the Kirby-Bauer disk diffusion method against 10 antibiotics from seven classes. Multiplex PCR was used to detect six pAmpC gene families (blaFOX, blaEBC, blaDHA, blaCIT, blaACC, and blaMOX) in all phenotypic AmpC producers.
Results: A total of 72 bacterial isolates comprising 51 (70.8%) E. coli and 21 (29.2%) K. pneumoniae were recovered. Phenotypic AmpC production was detected in 67 (93.1%) isolates, with a significantly higher prevalence in K. pneumoniae (100%) compared to E. coli (90.2%) (p=0.04). All 67 AmpC-producing isolates (100%) exhibited multidrug resistance (MDR) with MAR indices ranging from 0.3-0.7. High-level resistance was observed to β-lactams: and the β-lactam/β-lactamase inhibitor combination (100%). Resistance to the monobactam aztreonam was 95.5%, while the folate pathway inhibitor trimethoprim-sulfamethoxazole showed 98.5% resistance. The carbapenem imipenem remained highly effective (97.0% susceptibility), followed by the aminoglycoside amikacin (89.6%) and the fluoroquinolone ofloxacin (82.1%). The blaFOX gene was present in 100% of E. coli but only 52.4% of K. pneumoniae isolates (p<0.001). Co-carriage of all six pAmpC gene families was observed in 52.4% of K. pneumoniae and 100% of E. coli isolates. Significant associations were found between sample source and blaFOX carriage in K. pneumoniae (p=0.002).
Conclusion: This study reveals a remarkably high prevalence of genotypically diverse pAmpC genes with alarming MDR profiles among clinical E. coli and K. pneumoniae isolates in Abakaliki, Nigeria. The universal co-carriage of five pAmpC gene families and species-specific distribution of blaFOX highlight the complex molecular epidemiology of resistance in this setting. The sustained efficacy of carbapenems, amikacin, and ofloxacin provides therapeutic options, but urgent antimicrobial stewardship and infection control measures are required to prevent further spread of these resistance determinants.
Keywords:
AmpC β-lactamases, Escherichia coli, Klebsiella pneumoniaeDOI
https://doi.org/10.22270/jddt.v16i4.7711References
1. Jacoby GA. AmpC β-lactamases. Clin Microbiol Rev. 2009;22(1):161-182. https://doi.org/10.1128/CMR.00036-08 PMid:19136439 PMCid:PMC2620637
2. Nwojiji EC, Okolo IO, Osuji CA, Aniokete UC, Akomolafe SO, Okekeaji U, et al. Molecular detection of ampicillinase blaEBCM, blaFOX and blaDHAM resistant genes in multi-drug resistant Gram-negative bacteria. GSC Biol Pharm Sci. 2025;31(2):113-122. https://doi.org/10.30574/gscbps.2025.31.2.0181
3. Akpu PO, Uzoeto HO, Peter IU, Nomeh OL, Nwuzo AC, Ogba RC, et al. First report occurrence of CIT and DHA AmpC β-lactamase gene in Escherichia coli and Klebsiella pneumoniae from clinical samples in South Eastern Nigeria. Asian J Biochem Genet Mol Biol. 2023;13(1):30-36. https://doi.org/10.9734/ajbgmb/2023/v13i1285
4. Nwojiji EC, Ugbala DE, Ogbonna IP, Aniokete UC, Awoke OO, Peter IU, et al. Phenotypic screening and antibiotic susceptibility patterns of AmpC β-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates obtained from wound samples. Int J Adv Res Med. 2025;5:56-67. https://doi.org/10.22271/27069567.2025.v7.i2a.623
5. Philippon A, Arlet G, Jacoby GA. Plasmid-determined AmpC-type β-lactamases. Antimicrob Agents Chemother. 2002;46:1-11. https://doi.org/10.1128/AAC.46.1.1-11.2002 PMid:11751104 PMCid:PMC126993
6. Tamma PD, Doi Y, Bonomo RA, Johnson JK, Simner PJ, Antibacterial Resistance Leadership Group. Primer on AmpC β-lactamases: necessary knowledge for an increasingly multidrug-resistant world. Clin Infect Dis. 2019;69(8):1446-1455. https://doi.org/10.1093/cid/ciz173 PMid:30838380 PMCid:PMC6763639
7. Ejikeugwu C, Esimone C, Iroha IR, Ugwu C, Ezeador C, Duru C, et al. First detection of FOX-1 AmpC β-lactamase gene expression among Escherichia coli isolated from abattoir samples in Abakaliki, Nigeria. Oman Med J. 2018;33(3):243-249. https://doi.org/10.5001/omj.2018.44 PMid:29896333 PMCid:PMC5971057
8. Pérez-Pérez FJ, Hanson ND. Detection of plasmid-mediated AmpC β-lactamase genes in clinical isolates by using multiplex PCR. J Clin Microbiol. 2002;40:2153-2162. https://doi.org/10.1128/JCM.40.6.2153-2162.2002 PMid:12037080 PMCid:PMC130804
9. Miró E, Agüero J, Larrosa MN, Fernández A, Conejo MC, Bou G, et al. Prevalence and molecular epidemiology of acquired AmpC β-lactamases and carbapenemases in Enterobacteriaceae isolates from 35 hospitals in Spain. Eur J Clin Microbiol Infect Dis. 2013;32(2):253-259. https://doi.org/10.1007/s10096-012-1737-0 PMid:22956023
10. Sikora A, Zahra F. Nosocomial infections. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2021.
11. Saffar H, Niaraki NA, Tali AG, Baseri Z, Abdollahi A, Yalfani R. Prevalence of AmpC β-lactamase in clinical isolates of Escherichia coli, Klebsiella species and Proteus mirabilis in a tertiary hospital in Tehran, Iran. Jundishapur J Microbiol. 2016;9(12):e39121. https://doi.org/10.5812/jjm.39121 PMid:27127593 PMCid:PMC4842250
12. Akpu PO, Nomeh OL, Moneth EC, Aduaka OS, Ogba RC, Peter IU, et al. Phenotypic detection of AmpC β-lactamase producing Escherichia coli among patients in hospital wards. J Adv Microbiol. 2023;23(1):26-34. https://doi.org/10.9734/jamb/2023/v23i1702
13. Tofteland S, Dahl KH, Aasnæs B, Sundsfjord A, Naseer U. A nationwide study of mechanisms conferring reduced susceptibility to extended spectrum cephalosporins in clinical Escherichia coli and Klebsiella species isolates. Scand J Infect Dis. 2012;44(12):927-933. https://doi.org/10.3109/00365548.2012.707330 PMid:22991975
14. Bush K, Jacoby GA. Updated functional classification of β-lactamases. Antimicrob Agents Chemother. 2010;54(3):969-976. https://doi.org/10.1128/AAC.01009-09 PMid:19995920 PMCid:PMC2825993
15. Uzoeto H, Edemekong CI, Ogbonna IP, Peter IU. Antimicrobial resistance profiles of biofilm-forming E. coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae isolates from chronic wound infection. In: Proceedings of the 4th International Electronic Conference on Antibiotics. Basel: MDPI; 2025.
16. Peter IU, Obike OC, Ngwu JN, Emeruwa AP, Okolo IO, Mohammed ID. Prevalence of biofilm-forming and carbapenemase-producing Gram-negative bacilli colonizing indwelling urinary catheters of patients. UMYU Scientifica. 2025;4(2):270-284. https://doi.org/10.56919/usci.2542.027
17. Nobili G, Cocomazzi A, Basanisi MG, Damato AM, Coppola R, Cariglia MG, et al. Occurrence and genomic characterization of ESBL, AmpC-, and carbapenemase-producing Escherichia coli and Klebsiella pneumoniae isolated from surface water in Southern Italy, 2023-2024. Microorganisms. 2026;14(2):508. https://doi.org/10.3390/microorganisms14020508 PMid:41753794 PMCid:PMC12943021
18. Dave R, Joshi A. Occurrence of ESBL, AmpC-ESBL, and carbapenemase producer organisms in clinical specimens: an observational prospective study. J Pure Appl Microbiol. 2025;19(2):1541-1550. https://doi.org/10.22207/JPAM.19.2.59
19. Salmuna ZN, Hassan SA, Mohd Nawi SF, et al. Phenotypic and genotypic identification of four cases of plasmid-mediated AmpC β-lactamases-producing Escherichia coli admitted to a tertiary centre. Cureus. 2024;16(7):e64829. https://doi.org/10.7759/cureus.64829 PMid:39156293 PMCid:PMC11330189
20. Adebiyi I, Balogun S. Prevalence of plasmid-mediated Ampicillinase C genes in some Gram-negative ESKAPEE bacteria isolated from tertiary hospitals in southwest Nigeria [preprint]. 2025. https://doi.org/10.14293/PR2199.001407.v1
21. Maduakor UC, Immaculate CA, Anulika OO. AmpC beta-lactamase prevalence in isolates of Escherichia coli and Klebsiella pneumoniae in Enugu, Nigeria. J Adv Med Pharm Sci. 2022;24(5):16-26. https://doi.org/10.9734/jamps/2022/v24i530300
22. Yusuf I, Arzai AH, Haruna M, Sharif AA, Getso MI. Detection of multi drug resistant bacteria in major hospitals in Kano, North-West, Nigeria. Braz J Microbiol. 2014;45(3):791-798. https://doi.org/10.1590/S1517-83822014000300005 PMid:25477909 PMCid:PMC4204960
23. Ilang DC, Peter IU, Iroha IR. Antibiotic resistance profile of clinical importance biofilm forming extended spectrum beta-lactamase and carbapenemase phenotype in Gram-negative bacteria isolates. Int J Pharmacogn Life Sci. 2023;4(2):120-127. https://doi.org/10.33545/27072827.2023.v4.i2b.97
24. Bonura C, Giuffrè M, Aleo A, Fasciana T, Di Bernardo F, Stampone T, et al. An update of the evolving epidemic of blaKPC carrying Klebsiella pneumoniae in Sicily, Italy, 2014: emergence of multiple non-ST258 clones. PLoS One. 2015;10(7):e0132936. https://doi.org/10.1371/journal.pone.0132936 PMid:26177547 PMCid:PMC4503429
25. Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing. 32nd ed. CLSI supplement M100. Wayne (PA): CLSI; 2022.
26. Edemekong CI, Iroha IR, Thompson MD, Okolo IO, Uzoeto HO, Ngwu JN, et al. Phenotypic characterization and antibiogram of non-oral bacteria isolates from patients attending dental clinic at Federal College of Dental Technology and Therapy Medical Center Enugu. Int J Pathog Res. 2022;11(2):7-19. https://doi.org/10.9734/ijpr/2022/v11i2207
27. Tekele SG, Teklu DS, Tullu KD, Birru SK, Legese MH. Extended-spectrum beta-lactamase and AmpC beta-lactamases producing gram-negative bacilli isolated from clinical specimens at International Clinical Laboratories, Addis Ababa, Ethiopia. PLoS One. 2020;15(11):e0241984. https://doi.org/10.1371/journal.pone.0241984 PMid:33180785 PMCid:PMC7660541
28. Mohamed ES, Khairy RM, Abdelrahim SS. Prevalence and molecular characteristics of ESBL and AmpC β-lactamase producing Enterobacteriaceae strains isolated from UTIs in Egypt. Antimicrob Resist Infect Control. 2020;9:1-9. https://doi.org/10.1186/s13756-020-00856-w PMid:33303028 PMCid:PMC7727156
29. Fam N, Gamal D, El Said M, Aboul-fad L, El Dabei E, El Attar S. Detection of plasmid-mediated AmpC beta-lactamases in clinically significant bacterial isolates in a research institute hospital in Egypt. Life Sci J. 2013;10(2):2294-2304.
30. Robatjazi S, Nikkhahi F, Niazadeh M, Marashi SMA, Peymani A, Javadi A, et al. Phenotypic identification and genotypic characterization of plasmid-mediated AmpC β-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates in Iran. Curr Microbiol. 2021;78(6):2317-2323. https://doi.org/10.1007/s00284-021-02479-9 PMid:33837818
31. Jomehzadeh N, Ahmadi K, Rahmani Z. Prevalence of plasmid-mediated AmpC β-lactamases among uropathogenic Escherichia coli isolates in Southwestern Iran. Osong Public Health Res Perspect. 2021;12(6):390-395.https://doi.org/10.24171/j.phrp.2021.0272 PMid:34965688 PMCid:PMC8721271
32. Jameel NA, Ejaz H, Zafar A, Amin H. Multidrug resistant AmpC β-lactamase producing Escherichia coli isolated from a paediatric hospital. Pak J Med Sci. 2014;30(1):181-184. https://doi.org/10.12669/pjms.301.4045 PMid:24639857 PMCid:PMC3955568
33. Park SD, Uh Y, Lee G, Lim K, Kim JB, Jeong SH. Prevalence and resistance patterns of extended-spectrum and AmpC β-lactamase in Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Salmonella serovar Stanley in a Korean tertiary hospital. J Microbiol. 2010;118(10):801-808. https://doi.org/10.1111/j.1600-0463.2010.02663.x PMid:20854475
34. Ye Q, Wu Q, Zhang S, Zhang J, Yang G, Wang H, et al. Antibiotic-resistant extended spectrum β-lactamase and plasmid-mediated AmpC-producing Enterobacteriaceae isolated from retail food products and the Pearl River in Guangzhou, China. Front Microbiol. 2017;8:96. https://doi.org/10.3389/fmicb.2017.00096 PMid:28217112 PMCid:PMC5289952
35. Jacoby GA, Mills DM, Chow N. Role of β-lactamases and porins in resistance to ertapenem and other β-lactams in Klebsiella pneumoniae. Antimicrob Agents Chemother. 2004;48:3203-3206. https://doi.org/10.1128/AAC.48.8.3203-3206.2004 PMid:15273152 PMCid:PMC478483
36. Zorgani A, Daw H, Sufya N, Bashein A, Elahmer O, Chouchani C. Co-occurrence of plasmid-mediated AmpC β-lactamase activity among Klebsiella pneumoniae and Escherichia coli. Open Microbiol J. 2017;11:195-202. https://doi.org/10.2174/1874285801711010195 PMid:29151996 PMCid:PMC5678236
37. Yilmaz NO, Agus N, Bozcal E, Oner O, Uzel A. Detection of plasmid-mediated AmpC beta-lactamase in Escherichia coli and Klebsiella pneumoniae. Indian J Med Microbiol. 2013;31(1):53-59. https://doi.org/10.4103/0255-0857.108723 PMid:23508430
38. Chérif T, Saidani M, Decré D, Boutiba-Ben Boubaker I, Arlet G. Co-occurrence of multiple AmpC β-lactamases in Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis in Tunisia. Antimicrob Agents Chemother. 2015;60(1):44-51. https://doi.org/10.1128/AAC.00828-15 PMid:26459902 PMCid:PMC4704229
39. Najjuka CF, Kateete DP, Lodiongo DK. Prevalence of plasmid-mediated AmpC beta-lactamases in Enterobacteria isolated from urban and rural folks in Uganda. AAS Open Res. 2020;3:62-67. https://doi.org/10.12688/aasopenres.13165.1 PMid:34549164 PMCid:PMC8422338
40. El-Hady S, Adel L. Occurrence and detection of AmpC β-lactamases among Enterobacteriaceae isolates from patients at Ain Shams University Hospital. Egypt J Med Hum Genet. 2015;16:239-244. https://doi.org/10.1016/j.ejmhg.2015.03.001
41. Pai H, Kang CI, Byeon JH. Epidemiology and clinical features of bloodstream infections caused by AmpC-type-β-lactamase-producing Klebsiella pneumoniae. Antimicrob Agents Chemother. 2004;48(10):3720-3728. https://doi.org/10.1128/AAC.48.10.3720-3728.2004 PMid:15388426 PMCid:PMC521917
Published
Abstract Display: 26 
PDF Downloads: 14 PDF Downloads: 1 How to Cite
Issue
Section
Copyright (c) 2026 Henrietta Uzoeto , Ismaila Danjuma Mohammed , Ugonna Cassandra Aniokete , Ikemesit Udeme Peter
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
How to Cite
.