Evaluation of the efficacy of cephalosporin antibiotics sold in Kano, Nigeria, against clinical bacterial isolates.

Abstract

Introduction. The evaluation of the efficacy of cephalosporin antibiotics sold in Kano, Nigeria, against clinical bacterial isolates is a timely and crucial public health concern. Cephalosporins are among the most widely used antibiotic classes globally due to their broad-spectrum activity and low toxicity. They play a vital role in the empirical treatment of infections involving both Gram-positive and Gram-negative bacteria. However, the increasing misuse and circulation of substandard or falsified antibiotics, especially in informal markets, threatens their therapeutic effectiveness. Gap statement. In Nigeria, several formal and informal reports of substandard antibiotics and their unregulated sale in open markets, such as Sabon Gari in Kano, raise serious concerns about the quality of drug and their potential contribution to antimicrobial resistance (AMR). Cephalosporins sold in these markets are often sourced and stored under questionable conditions, which increases the risk of reduced potency or inefficacy. At the same time, AMR continues to rise globally, and in low and middle-income countries like Nigeria, poor-quality antibiotics can worsen treatment failure and drive resistance. Sabon Gari market is a major distribution centre for pharmaceuticals, yet research on its impact and extent of substandard drugs is lacking. Aim. This study aims to assess the pharmaceutical quality of commonly sold cephalosporins purchased from drug distributors in Sabon Gari Market, Kano, by comparing their antimicrobial activity against a panel of clinical bacterial isolates (Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa and Salmonella sp.) with that of standard reference antibiotics. Methodology. Antimicrobial susceptibility pattern of the test isolates was determined by the disc diffusion method. Fourier transform infrared spectroscopy analysis was used to confirm the functional group of the active ingredients of all the antibiotics tested. Molecular identification of the resistant gene (CTX-M1) was carried out using PCR. Results. Market survey (n=100) reveals that among drug distributors in Sabon Gari Market, Kano, cephalexin 61% (first generation); cefuroxime 72% (second generation); cefixime 68%, cefpodoxime 79%, ceftriaxone 63%, ceftazidime 70% and cefotaxime 45% (third generation); cefepime 84% (fourth generation) were the most commonly sold cephalosporins, with different brands and company names. These percentages represent the proportion of respondents who reported each antibiotic as one of their most frequently sold products. There is no significant difference between the branded antibiotics (drugs purchased in the market) and standard drugs. Exactly 20% of E. coli and K. pneumoniae were resistant, while 80% of Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas and Salmonella sp. were susceptible. The CTX-M1 resistant gene was identified in E. coli and K. pneumoniae, which further confirms their resistance to cefotaxime and ceftriaxone antibiotics. Conclusion. Branded cephalosporins sold in Kano were chemically intact and structurally aligned with their respective formulations. No missing or anomalous functional groups were observed that would suggest substandard or counterfeit products, thus fit for human intake.