Anti-Brucella activity of Caryopteris mongolica Bunge root extract against Brucella melitensis infection in mice

Antibiotic resistance modifying ability of phytoextracts in anthrax biological agent Bacillus anthracis and emerging superbugs: a review of synergistic mechanisms

Background and objectives

The chemotherapeutic management of infections has become challenging due to the global emergence of antibiotic resistant pathogenic bacteria. The recent expansion of studies on plant-derived natural products has lead to the discovery of a plethora of phytochemicals with the potential to combat bacterial drug resistance via various mechanisms of action. This review paper summarizes the primary antibiotic resistance mechanisms of bacteria and also discusses the antibiotic-potentiating ability of phytoextracts and various classes of isolated phytochemicals in reversing antibiotic resistance in anthrax agent Bacillus anthracis and emerging superbug bacteria.

Methods

Growth inhibitory indices and fractional inhibitory concentration index were applied to evaluate the in vitro synergistic activity of phytoextract-antibiotic combinations in general.

Findings

A number of studies have indicated that plant-derived natural compounds are capable of significantly reducing the minimum inhibitory concentration of standard antibiotics by altering drug-resistance mechanisms of B. anthracis and other superbug infection causing bacteria. Phytochemical compounds allicin, oleanolic acid, epigallocatechin gallate and curcumin and Jatropha curcas extracts were exceptional synergistic potentiators of various standard antibiotics.

Conclusion

Considering these facts, phytochemicals represents a valuable and novel source of bioactive compounds with potent antibiotic synergism to modulate bacterial drug-resistance.

Doxycycline-encapsulated solid lipid nanoparticles as promising tool against Brucella melitensis enclosed in macrophage: a pharmacodynamics study on J774A.1 cell line

Background

Brucellosis is a zoonotic disease caused by Brucella species. It has been estimated that more than 500,000 new cases of Brucellosis occur annually all around the world. Relapse of the disease is one of the most important challenges. The most important reason for the relapse of brucellosis is the survival of the bacteria inside the macrophages, which makes them safe from the immune system and disrupts drug delivery mechanism.

Objectives

The present study was performed to assess the effects of Doxycycline-loaded Solid Lipid Nanoparticles (DOX-SLN) on the Brucella melitensis inside macrophages.

Methods

DOX-SLN was prepared using double emulsion method. The technological characterization of DOX-SLN, including particle size, zeta potential, polydispersity index (PDI), drug loading and encapsulation efficiency were used. Fourier-transform infrared spectroscopy (FTIR) and Differential scanning calorimetry (DSC) were used to assess the interactions between Nanoparticles (NPs) components and crystalline form of doxycycline. Moreover, the effect of DOX-SLN on the bacteria were compared with that of the doxycycline using various methods, including well diffusion, Minimum Inhibitory Concentration (MIC), and investigation of their effects on murine macrophage-like cells cell line J774A.1.

Results

The means of particle size, zeta potential, PDI, drug loading and encapsulation efficiency were 299 ± 34 nm, − 28.7 ± 3.2 mV, 0.29 ± 0.027, 11.2 ± 1.3%, and 94.9 ± 3.2%, respectively. The morphology of NPs were spherical with a smooth surface. No chemical reaction was occurred between the components. Doxycycline was located within NP matrix in its molecular form. The DOX-SLN significantly decreased the microbial loading within macrophages (3.5 Log) in comparison with the free doxycycline.

Conclusions

Since the DOX-SLN showed better effects on B. melitensis enclosed in macrophages than the free doxycycline, it is recommended to use it for treating brucellosis and preventing relapse.

ANTIBIOTICS IN THE MANAGEMENT OF BRUCELLOSIS

Brucellosis is the most common zoonotic bacterial infection in the world. The causative organism is Brucella spp. and the incubation of period is 5 days to 5 months. Although immunological tests are widely used for the diagnosis but cultures of the blood or other clinical specimens is the gold standard for the diagnosis. Outbreaks of brucellosis occur from time to time. It spreads mostly in the communities having close contact with the sheep and cattle, like farmers, cattle grazers, veterinary workers, and butchers. In the urban situation the outbreaks usually occur due to consumption of unpasteurized milk or its products. The clinical features of brucellosis are protean but the major one is a prolonged fever. Infected animals are the reservoirs and the sources of infection. Antibiotics have a major role in the management of brucellosis. Although a single antibiotic may be effective but a combination is preferred to prevent the chances of development of resistance and recurrence of disease. Antibiotics commonly used in the management of brucellosis are doxycycline, rifampicin, streptomycin, fluoroquinolones, cotrimoxazole, and chloramphenicol. Resistance to one or the other antibiotic have been reported from time to time. Dual therapy is commonly prescribed and triple therapy is used in serious conditions like neuro-brucellosis, endocarditis, or recurrence. The objective of this review was to evaluate the effects of various antibiotic regimens in the management of brucellosis. Antibiotic resistance is a problem which can aggravate the situation in future. We suggest that antibiotics’ use should be rationalized to prevent future drug resistance. At least dual therapy should be used to prevent the chances of recurrence and triple therapy for complicated cases and in cases of relapse. There should be no compromise on the optimal doses and duration of therapy.

An Overview of Brucellosis in Cattle and Humans, and its Serological and Molecular Diagnosis in Control Strategies

Brucellosis is one of the most common contagious and communicable zoonotic diseases with high rates of morbidity and lifetime sterility. There has been a momentous increase over the recent years in intra/interspecific infection rates, due to poor management and limited resources, especially in developing countries. Abortion in the last trimester is a predominant sign, followed by reduced milk yield and high temperature in cattle, while in humans it is characterized by undulant fever, general malaise, and arthritis. While the clinical picture of brucellosis in humans and cattle is not clear and often misleading with the classical serological diagnosis, efforts have been made to overcome the limitations of current serological assays through the development of PCR-based diagnosis. Due to its complex nature, brucellosis remains a serious threat to public health and livestock in developing countries. In this review, we summarized the recent literature, significant advancements, and challenges in the treatment and vaccination against brucellosis, with a special focus on developing countries.