Investigation of Antimicrobial Activity of Solanum nigrum and Saponaria officinalis Extracts Against Acinetobacter baumannii

Acinetobacter baumannii is a non-fermentative gram-negative bacterium that is common in nosocomial infections. As an opportunistic pathogen in hospitals, it is resistant to a large number of antibiotics and responsible for numerous infections such as bacteremia, pneumonia, meningitis, urogenital infections, and surgical wound infections.

We isolated 10 strains of Acinetobacter baumannii from urine samples of patients referring to Zabol Hospital. Solanum nigrumandSaponaria officinalis plants were harvested from Zabol city, dried in shade, milled, placed in a solvent solution (96% ethanol) for 24 h, and extracted using a rotary machine. The minimum inhibitory concentration (MIC) and the least bactericidal concentration were determined by the microdilution method.

The results of the antibiotic resistance testing showed that 100% of the strains were susceptible to antibiotics ceftazidime, gentamycin, and azithromycin while only 16.6% were resistant to ampicillin. The results of antimicrobial activity analysis showed that the leastminimuminhibitory concentration of Saponaria officinalis leaves extract was 25ppmagainst A. baumannii. Nine strains were inhibited at this concentration and one strain survived at all concentrations. The lowest minimum inhibitory concentration of Solanum nigrum extract was 12.5, with two strains being inhibited at this concentration and seven strains being inhibited at 25.

This study showed antimicrobial effects of Solanum nigrum and Saponaria officinalis extracts against A. baumannii. Therefore, they can be proposed as treatments for infections caused by this bacterium.