Version 1: Efflux Pump Activity and Endotoxin Levels in Salmonella enterica Resistant to Ciprofloxacin

Antibiotic resistance and virulence are both natural processes used by bacteria to survive. Antibiotic resistance affects virulence factors and fitness directly or indirectly. Given the association between efflux pump overexpression and lipopolysaccharide (LPS), the endotoxin production may be affected as they are both located in the cell wall. 

Objective The study's goal is to determine the efflux pump activity as a key part of antibiotic resistance in Gram-negative bacteria and corelate with the production of endotoxin, which is a major factor in the virulence of Salmonella Spp. isolates. The efflux pumps expel antimicrobial agents as well as toxic substances and metabolites. Their activity assessed in seven resistant isolates of Salmonella Spp using the Ethidium Bromide (EtBr) cartwheel method. Method: principle depends on the ability of bacteria to extrude an Ethidium Bromide (EtBr) as substrate through an efflux pump, and endotoxin measured by ELISA 

Results isolates that fluorescence at concentrations 1 µg/mL, 1.5 µg/mL, 2 µg/mL, and 2.5 µg/mL, which indicated inactive efflux pumps, whereas active efflux pumps did not exhibit fluorescence detected at 0.5 µg/mL. The observations were documented using a UV illuminator. The endotoxin level concentrations in resistant isolates was an average concentration of 3.472 ± 0.4036 ng/ml (34.72 EU/ml) compared to 3.092 ± 0.3338 ng/ml (30.92 EU/ml) in sensitive isolates. Conclusion: The difference in endotoxin levels between resistant and sensitive isolates was not statistically significant (P ≥ 0.4), indicate the resistance has no impact on endotoxin level