Antimicrobial Activity of Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 Against Staphylococcus aureus Biofilms Isolated from Wound Infection.


Algburi A(1)(2), Al-Hasani HM(3), Ismael TK(4), Abdelhameed A(3), Weeks R(5), Ermakov AM(6), Chikindas ML(5)(6).
Author information:
(1)Department of Biotechnology, College of Science, University of Diyala, Baqubah, Iraq. [Email]
(2)Department of Scholarship and Cultural Relations, Presidency of Diyala University, Baqubah, Iraq. [Email]
(3)Department of Biotechnology, College of Science, University of Diyala, Baqubah, Iraq.
(4)Educational Laboratories, General Teaching Hospital of Baqubah, Baqubah, Iraq.
(5)Health Promoting Naturals Laboratory, School of Environmental and Biological Sciences, Rutgers State University, New Brunswick, NJ, USA.
(6)Don State Technical University, Rostov-on-Don, Russia.


Staphylococcal wound infections range from mild to severe with life-threatening complications. The challenge of controlling such infections is related to bacterial biofilm formation, which is a major factor contributing to antibiotic resistance and infection recurrence. In this study, four clinical isolates of staphylococci species; two isolates of methicillin-resistant Staphylococcus aureus (MRSA) and two methicillin-sensitive Staphylococcus aureus (MSSA) isolates. The identification of bacterial species based on cell morphology, initial biochemical tests, and the VITEK2 system were used to confirm the clinical microbiological diagnosis. Antibiotic sensitivity testing showed that the isolated staphylococci were highly resistant to the following antibiotics, amoxicillin, penicillin G, cefotaxime, and methicillin. Combinations of cefotaxime with the cell-free supernatants (CFS) of Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895, each one separately showed complementary activity against the tested staphylococci. The co-aggregation capability of the tested bacilli as beneficial bacteria against isolated staphylococci was also evaluated. The data showed a strong co-aggregation with scores (+ 3, + 4) which were reported between the bacilli strains and the isolated staphylococci. Furthermore, the CFS of bacilli strains showed an inhibitory effect against biofilm-associated MRSA and MSSA. These findings confirmed the ability of beneficial bacteria to compete with the pathogens at the site of colonization or for the source of nutrients and, eventually, lead to inhibition of the pathogens' capability of causing a wound infection. Such beneficial bacteria could play an important role in future pharmaceutical and industrial applications.