The correlation between PtfA, PfhA, and TadD fimbriae genes and biofilm formation in Pasteurella multocida virulence and multidrug-resistant nature

Abstract

Pasteurella multocida is a bacterium that has gotten a lot of attention because of the genetic differences between its strains. This study aimed to find out how the fimbrial gene of P. multocida affects biofilm formation and how it is related to antibiotic resistance. We isolated 20 (8 %) strains of P. multocida from 250 collected samples using PCR; these included 12 strains of serotype A, 2 strains of serotype B, and one strain of serotype E. Five spp. Strains were not categorized. Fimbrial genes PtfA, PfhA, and TadD were detected in all samples with different ratios; PtfA was found in 17 (85 %) samples and TadD in 12 (60 %) samples, while PfhA was expressed in 11 (55 %). In most cases, these three genes coexisted and led to a strong correlation between strains harboring them and biofilm formation. The majority of P. multocida strains demonstrated the ability to form weak and moderate biofilms, despite statistical analysis revealing no distinction between aerobic and microaerophilic conditions in biofilm formation; we observed a slight rise in OD values for strains grown in 5 % CO2. Most strains demonstrated resistance to at least two antibiotics, with a positive correlation between resistance to different antibiotics and the formation of weak and moderate biofilms. Penicillin-G exhibited the highest resistance, while azithromycin proved to be the most effective antibiotic, with 17 strains demonstrating varying levels of susceptibility to it. This study found that fimbrial genes play a decisive role in virulence by facilitating attachment, colonization, and assessing biofilm formation, leading to antibiotic resistance.