Effects of physicochemical changes (temperature, pH, and culture media) on strong biofilm formation of Acinetobacter baumannii isolated from patients with respiratory infection in Iraq


  • Shaymaa Sabah Mutashar
  • Nada H. A. L. Al-Mudallal
  • Dunya Jawad Ridha




Acinetobacter baumannii, antibiotic, biofilm genes, temperature, Covid-19


Introduction and Aim: The ability of Acinetobacter baumannii to form biofilms on biotic and abiotic surfaces is regulated by several pathogens’ virulence factors, and this is thought to be at the root of the bacteria's resistance to antibiotics. We hope to learn how temperature, pH, and iron concentrations influence the development of biofilms in A. baumannii isolated from COVID-19 and non-COVID-19 individuals, and which genes are relevant for biofilm formation and antibiotic resistance.


Materials and Methods: Eight strong adherent isolates of A. baumannii from respiratory tract infection Iraqi patients (4 from COVID-19 and the other from non-COVID-19 just respiratory patients) had been used in this study which conducted from 10/1/2021 to 10/2/2022. The antibiotic sensitivity of all isolates was determined using the VITEK-2 system. The biofilm associated genes OXA-51, bap, Chaperone Usher (CsuE) and Integron-1, was detected using PCR. Isolates of A. baumainni were put through a battery of tests to determine whether they possessed the capacity to produce robust biofilms under a wide range of both physical (temperature, pH) and chemical circumstances.


Results: A. baumannii showed that all isolates were multidrug resistant and positive for the biofilm genes studied. Effect on temperature on biofilm formation showed at 44ºC biofilm formation was significantly lower than that at 37ºC (mean differences of 0.178000 (t= 8.355, df:3, P=0.004) and 0.204000 (t=26.521, df:3, P=0.000) respectively). The adhesion factor value in the COVID-19 positive and negative groups decreased significantly because of the pH change. Iron concentration of 60 µM significantly lowered biofilm formation among COVID-19 group and non-COVID-19 group.


Conclusion: A. baumanni are multidrug resistance isolates with a capacity to form biofilms. The ability to form biofilms by A. baumannii is strongly influenced by physical and chemical factors.

Author Biographies

Shaymaa Sabah Mutashar

National Center for Educational Laboratories, Medical City, Ministry of Health, Baghdad, Iraq

Nada H. A. L. Al-Mudallal

Department of Medical Microbiology, College of Medicine, Al-Iraqia University, Baghdad, Iraq

Dunya Jawad Ridha

National Center for Educational Laboratories, Medical City, Ministry of Health, Baghdad, Iraq


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How to Cite

Sabah Mutashar S, Al-Mudallal NHAL, Jawad Ridha D. Effects of physicochemical changes (temperature, pH, and culture media) on strong biofilm formation of Acinetobacter baumannii isolated from patients with respiratory infection in Iraq . Biomedicine [Internet]. 2023 Feb. 26 [cited 2023 Dec. 2];43(1):157-63. Available from: https://biomedicineonline.org/index.php/home/article/view/2433

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