In Vitro and In Vivo Control of Secondary Bacterial Infection Caused by Leishmania major
Abstract: Bacterial infections of cutaneous leishmaniasis cause skin ulcers on mice, resulting in
increased tissue deterioration, and these infections can be controlled with liquid allicin. To isolate and
identify the incidences of real secondary bacterial infections in mice, we performed the current
study by injecting mice (n = 50) with Leishmania major. L. major infections were initiated by
an intramuscular injection of 0.1 mL Roswell Park Memorial Institute (RPMI 1640 media/mouse
(107 promastigote/mL)). Scarring appeared 2–6 weeks after injection, and the bacteria were isolated
from the skin ulcer tissues. Allicin (50 L/mL) and ciprofloxacin (5 g; Cip 5) were used for
controlling L. major and bacteria. One hundred samples from skin ulcers of mice were examined,
and 200 bacterial colonies were isolated. Forty-eight different genera and species were obtained and
identified by Gram staining and physiological and biochemical characterization using identification
kits. All samples were positive for secondary bacterial infections. Of the isolates, 79.16% were
identified as Gram-negative bacteria, and 28.84% were identified as Gram-positive bacteria; only one
yeast species was found. Interestingly, pure allicin liquid at a concentration 50 L/mL exhibited
antibacterial activity against a wide range of Gram-negative and some Gram-positive bacteria,
in addition to yeast, and was 71.43% effective. Antimicrobial resistance patterns of all genera and
species were determined using 15 different antibiotics. Allicin (50 L/mL) and Cip 5 were the most
effective against L. major and 92.30% of isolated bacteria. Stenotrophomonas maltophilia was the most
resistant bacterium to the tested antibiotics with a survival rate of 73.33%, and it exhibited resistance
to allicin.
Keywords: bacteria; cutaneous leishmaniasis; Leishmania major; histopathological analysis; ciprofloxacin
