Antibiogram and Molecular Detection of β-Lactamase Genes (blaTEM and blaSHV) in Clinical Isolates from Nigeria

Antimicrobial resistance (AMR) among Gram-negative bacteria represents a major public health challenge in Nigeria and across Sub-Saharan Africa, particularly resistance to β-lactam antibiotics mediated by plasmid-encoded β-lactamase genes. This study assessed phenotypic antibiotic resistance patterns and the presence of blaTEM and blaSHV genes among 40 archived Gram-negative clinical bacterial isolates obtained from urine and wound samples in Nigeria. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disk diffusion method following Clinical and Laboratory Standards Institute guidelines. Molecular detection of resistance genes was carried out using polymerase chain reaction (PCR). Very high resistance rates were observed against ceftazidime (97.7%), cefuroxime (≈99%), amoxicillin–clavulanic acid (≈92–100%), and ciprofloxacin (92%). Relatively higher susceptibility was recorded for nitrofurantoin, gentamicin, and ofloxacin. Molecular analysis showed that 75% (15/20) of isolates screened carried the blaTEM gene, while all isolates screened for blaSHV (24/24; 100%) were positive. The study demonstrates extensive phenotypic resistance and a high prevalence of β-lactamase–encoding genes among Gram-negative clinical isolates in Nigeria, underscoring the urgent need for integrated phenotypic and molecular AMR surveillance and strengthened antimicrobial stewardship.

Antimicrobial resistance; Gram-negative bacteria; β-lactamase genes

1. Altayb, H. N., Siddig, M. A., El Amin, N. M., & Mukhtar, M. M. (2021). Prevalence of blaCTX-M, blaTEM, and blaSHV Genes among Extended-spectrum?-Lactamases-Producing Clinical Isolates of Enterobacteriaceae in Different Regions of Sudan. Sudan Journal of Medical Sciences, 16(1), 5-16. [Google Scholar] [Crossref]

2. Ampaire, L., Muhindo, A., Orikiriza, P., Mwanga-Amumpaire, J., Boum, Y., & Bebell, L. (2016). A review of antimicrobial resistance in East Africa. African journal of laboratory medicine, 5(1), 1-6. [Google Scholar] [Crossref]

3. Bebell, L. M., & Muiru, A. N. (2014). Antibiotic use and emerging resistance: how can resource-limited countries turn the tide?. Global heart, 9(3), 347-358. [Google Scholar] [Crossref]

4. Bernabe, K. J., Langendorf, C., Ford, N., Ronat, J. B., & Murphy, R. A. (2017). Antimicrobial resistance in West Africa: a systematic review and meta-analysis. International journal of antimicrobial agents, 50(5), 629-639. [Google Scholar] [Crossref]

5. Binagwaho, A., & Ghebreyesus, T. A. (2019). Primary healthcare is cornerstone of universal health coverage. bmj, 365. [Google Scholar] [Crossref]

6. Cipriano, P., Chau, J., Jashi, M., Kickbusch, I., Koonin, J., Mofokeng, T., ... & Shiozaki, A. (2024). Leveraging universal health coverage to leave no one behind in tackling AMR. The Lancet Global Health, 12(9), e1389-e1390. [Google Scholar] [Crossref]

7. Dirar, M. H., Bilal, N. E., Ibrahim, M. E., & Hamid, M. E. (2020). Prevalence of extended-spectrum β-lactamase (ESBL) and molecular detection of bla TEM, bla SHV and bla CTX-M genotypes among Enterobacteriaceae isolates from patients in Khartoum, Sudan. Pan African Medical Journal, 37(1). [Google Scholar] [Crossref]

8. Ehlers, M. M., Veldsman, C., Makgotlho, E. P., Dove, M. G., Hoosen, A. A., & Kock, M. M. (2009). Detection of bla SHV, bla TEM and bla CTX-M antibiotic resistance genes in randomly selected bacterial pathogens from the Steve Biko Academic Hospital. FEMS Immunology & Medical Microbiology, 56(3), 191-196. [Google Scholar] [Crossref]

9. Gandra, S., Alvarez-Uria, G., Turner, P., Joshi, J., Limmathurotsakul, D., & van Doorn, H. R. (2020). Antimicrobial resistance surveillance in low-and middle-income countries: progress and challenges in eight South Asian and Southeast Asian countries. Clinical microbiology reviews, 33(3), 10-1128. [Google Scholar] [Crossref]

10. Guzmán, M., Rodríguez, E., Antón, K., Silva, S., Navarro, J., Lastra, L., & Alonso, G. (2013). Genes blaTEM, blaSHV y blaCTX-M en enterobacterias productoras de b-lactamasas de espectro extendido aisladas de pacientes con infección intrahospitalaria. Investigación Clínica, 54(3), 235-245. [Google Scholar] [Crossref]

11. Iheanacho, C. O., & Eze, U. I. (2022). Antimicrobial resistance in Nigeria: challenges and charting the way forward. European Journal of Hospital Pharmacy, 29(2), 119-119. [Google Scholar] [Crossref]

12. Kpoda, D. S., Ajayi, A., Somda, M., Traore, O., Guessennd, N., Ouattara, A. S., ... & Dosso, M. (2018). Distribution of resistance genes encoding ESBLs in Enterobacteriaceae isolated from biological samples in health centers in Ouagadougou, Burkina Faso. BMC research notes, 11(1), 471. [Google Scholar] [Crossref]

13. Lewnard, Joseph A., Esmita Charani, Alec Gleason, Li Yang Hsu, Wasif Ali Khan, Abhilasha Karkey, Clare IR Chandler et al. "Burden of bacterial antimicrobial resistance in low-income and middle-income countries avertible by existing interventions: an evidence review and modelling analysis." The Lancet 403, no. 10442 (2024): 2439-2454. [Google Scholar] [Crossref]

14. Magiorakos, A. P., Srinivasan, A., Carey, R. B., Carmeli, Y., Falagas, M. E., Giske, C. G., ... & Monnet, D. L. (2012). Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clinical microbiology and infection, 18(3), 268-281. [Google Scholar] [Crossref]

15. Mariita, K. M., Chirima, H. A., & Maina, C. K. (2018). Broad spectrum antibiotic use among in-patients at a hospital in Nairobi, Kenya. International Journal of Basic & Clinical Pharmacology, 8, 1-7. [Google Scholar] [Crossref]

16. Ogbolu, D. O., Alli, O. A., Oluremi, A. S., & Onifade, C. O. (2018). Erythromycin resistance determinants in clinical Gram-positive cocci isolated from Nigerian patients. J Clin Diagn Res, 12, 5-10. [Google Scholar] [Crossref]

17. Ogbolu, D. O., Piddock, L. J., & Webber, M. A. (2020). Opening Pandora's box: High-level resistance to antibiotics of last resort in Gram-negative bacteria from Nigeria. Journal of Global Antimicrobial Resistance, 21, 211-217. [Google Scholar] [Crossref]

18. Ogbolu, D. O., Terry Alli, O. A., Webber, M. A., Oluremi, A. S., & Oloyede, O. M. (2018). CTX-M-15 is established in most multidrug-resistant uropathogenic Enterobacteriaceae and Pseudomonaceae from hospitals in Nigeria. European Journal of Microbiology and Immunology, 8(1), 20-24. [Google Scholar] [Crossref]

19. Porter, G. J., Owens, S., & Breckons, M. (2021). A systematic review of qualitative literature on antimicrobial stewardship in Sub-Saharan Africa. Global Health Research and Policy, 6(1), 31. [Google Scholar] [Crossref]

20. Samreen, A. I., Malak, H. A., & Abulreesh, H. H. (2021). Environmental antimicrobial resistance and its drivers: a potential threat to public health. J Glob Antimicrob Resist 27: 101–111. [Google Scholar] [Crossref]

21. Sulis, G., Batomen, B., Kotwani, A., Pai, M., & Gandra, S. (2021). Sales of antibiotics and hydroxychloroquine in India during the COVID-19 epidemic: An interrupted time series analysis. PLoS medicine, 18(7), e1003682. [Google Scholar] [Crossref]

22. Teixeira, M. J., Pretorius, V., Hunt, R. C., Morar, S., Colloty, J. L., Radebe, C. M., & Morar, R. (2025). A retrospective analysis of uropathogens isolated and antimicrobial susceptibility patterns at a regional hospital in North West province, South Africa. African Journal of Laboratory Medicine, 14(1), 2845. [Google Scholar] [Crossref]

23. Thanh, L. N., Wernli, D., Målqvist, M., & Jørgensen, P. S. (2025). ‘When global health meets global goals’: assessing the alignment between antimicrobial resistance and sustainable development policies in 10 African and Asian countries. BMJ Global Health, 10(3). [Google Scholar] [Crossref]

24. Totaro, V., Guido, G., Cotugno, S., De Vita, E., Asaduzzaman, M., Patti, G., ... & Saracino, A. (2025). Antimicrobial Resistance in Sub-Saharan Africa: a comprehensive landscape review. The American Journal of Tropical Medicine and Hygiene, 113(2), 253. [Google Scholar] [Crossref]

25. Williams-Walker, A., Lammie, L., & Moore, C. E. (2025). P57 Prevalence of antimicrobial resistance in acute community-acquired urinary tract infections in Sub-Saharan Africa: a systematic review. JAC-Antimicrobial Resistance, 7(Supplement 4), dlaf230-064. [Google Scholar] [Crossref]

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