Evaluation of in vitro and in vivo antibiotic efficacy against a novel bioluminescent Shigella flexneri

Abstract

Shigella spp., the bacteria responsible for shigellosis, are one of the leading causes of diarrheal morbidity and mortality amongst children. There is a pressing need for the development of novel therapeutics, as resistance of Shigella to many currently used antibiotics is rapidly emerging. This paper describes the development of robust in vitro and in vivo tools to study antibiotic efficacy against Shigella flexneri. A novel bioluminescent S. flexneri strain (S. flexneri lux1) was generated, which can be used in a mammalian epithelial cell co-culture assay to evaluate antibiotic intracellular and extracellular efficacy. In addition, the S. flexneri lux1 strain was used with an intraperitoneal (IP) murine model of shigellosis to test the efficacy of ciprofloxacin and ampicillin. Both antibiotics significantly reduced the observed radiance from the gastrointestinal tissue of infected mice compared to vehicle control. Furthermore, plated gastrointestinal tissue homogenate confirmed antibiotic treatment significantly reduced the S. flexneri infection. However, in contrast to the results generated with tissue homogenate, the radiance data was not able to distinguish between the efficacy of ampicillin and ciprofloxacin. Compared to traditional methods, these models can be utilized for efficient screening of novel antibiotics aiding in the discovery of new treatments against shigellosis.

Pharmaceutical Prospects of Bee Products: Special Focus on Anticancer, Antibacterial, Antiviral, and Antiparasitic Properties

“…Nonetheless, a general observation in several studies is that the antibacterial action of bee pollen is much higher towards Gram-positive bacteria than their Gram-negative counterparts [169,[171][172][173] with some exceptions [174,175]. It is important to note, however, that almost all the antibacterial data were generated in vitro, so it is urgent to confirm the antibacterial efficacy of bee products using currently available vertebrate [176][177][178][179] or invertebrate [180][181][182][183][184][185] in vivo model systems.…”

The repurposing of Tebipenem pivoxil as alternative therapy for severe gastrointestinal infections caused by extensively drug-resistant Shigella spp

“…The in vivo efficacy of Tebipenem pivoxil, Tebipenem free-base and Ciprofloxacin was evaluated using a previously published mouse model of shigellosis using S. flexneri lux1 ( McCloskey et al, 2019 ). S. flexneri lux1 expresses a bacterial luciferase reporter as previously described and was created from S. flexneri M90T Sm (ATCC BAA-2402) purchased from the American Type Culture Collection (ATCC, Manassas, VA).…”

“…For infections, an overnight S. flexneri lux1 broth culture containing 30 µg/mL streptomycin (selection of lux1) and 0.1% sodium deoxycholate (for expression of Shigella invasion proteins [ McCloskey et al, 2019 ]) was diluted 1:100 and grown to log-phase (3–4 hr). Log-phase bacteria (OD 600 ~ 0.4) were centrifuged, and the resulting pellet was washed in DPBS without calcium and magnesium (Thermo Fisher Scientific).…”

Assessment of Histopathological Changes in the Liver and Spleen of Mice Infected with Salmonella typhi Following Treatment with Ciprofloxacin

“…Group two was used as a control. Ciprofloxacin was administered orally, once per day , with a total daily dose of 100 mg \ kg of body weight, At 3 days post infection, a maxim-um dose was used according to previous methods [13,14]. The results were interpreted in relation to animal survival and observed toxicity [15].…”