African Journal of

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12269

Full Length Research Paper

Incidence and antimicrobial susceptibility pattern of extended-spectrum-β-lactamase-producing Escherichia coli isolated from retail imported mackerel fish

Nasreldin Elhadi*
  • Nasreldin Elhadi*
  • Department of Clinical Laboratory Science, College of Applied Medical Sciences, University of Dammam, Dammam 31441, Saudi Arabia.
  • Google Scholar
Khaldoon Alsamman
  • Khaldoon Alsamman
  • Department of Clinical Laboratory Science, College of Applied Medical Sciences, University of Dammam, Dammam 31441, Saudi Arabia.
  • Google Scholar

  •  Received: 04 May 2015
  •  Accepted: 08 June 2015
  •  Published: 10 June 2015


During the past few years, extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and other species of Enterobacteriaceae have become a matter of great concern in human and veterinary medicine. Several studies in recent years documented the prevalence and occurrence of ESBL-producing Enterobacteriaceae in food products such as meat, poultry and raw milk; therefore in this pilot study we examined imported raw frozen mackerel fish to determine the incidence of ESBL-producing E. coli from Eastern Province of Saudi Arabia. From January to March, 2012, 45 samples were purchased from various supermarkets of this region and examined for the presence of ESBL-producing E. coli using ChromID ESBL agar plates and further confirmed by PCR amplification. Out of 45 mackerel fish samples, 23 (51.1%) were found to be positive for ESBL-producing E. coli and yielded 60 isolates. The higher rate of resistance was found to be with ampicillin (100%), piperacillin (96.7%), cefotaxime (93.3%), ceftriaxone (93.3%), tetracycline (53.3%), nalidixic acid (40%) and trimethoprim (30%). The least rate of resistance was recorded among chloramphenicol (15%), ciprofloxacin (15%), noroxin (11.7%) and nitrofurantoin (5%). All the 60 isolates in this study were found susceptible to amikacin, aztreonam, cefepime, ertapenem, gentamicin and kanamycin. Further characterization by PCR revealed that 49 (82%) out of 60 isolates of ESBL-producing E. coli were confirmed to be blaCTX-M type and were negative for blaTEM and blaSHV genes. This is the first study to demonstrate the occurrence of ESBL-producing E. coli in imported raw frozen mackerel fish in Saudi Arabia and the study result indicates that the mackerel fish might be the possible reservoir of blaCTX-M gene and may contribute to the dissemination and transfer of these β-lactamase genes to humans through food chain. The high rate of occurrence of ESBL-producing E. coli in the mackerel fish indicates that there is an established reservoir of these bacteria in the mackerel fish. Further national wide studies are necessary to assess future trends in imported fish to Saudi Arabia.


Key words: Mackerel fish, Escherichia coli, extended-spectrum β-lactamase (ESBL), antimicrobial resistance, PCR.


ESBL, Extended-spectrum β-lactamase; ND, non-determinable; BAM, bacteriological analytical manual.