Streptokinase production from Streptococcus dysgalactiae subsp. equisimilis SK-6 in the presence of surfactants, growth factors and trace elements

Evaluation of clinical efficacy of streptokinase by comparison with the thrombolytic agent on animal model

Cardiovascular disorders, including acute myocardial infarction (AMI), often lead to blood clot formation, impacting blood circulation. Streptokinase, a cost-effective and widely available thrombolytic agent, is crucial in treating thrombosis. This study aimed to produce streptokinase from Streptococcus pyogenes EBL-48 and compare its efficacy with heparin in an animal model. We evaluated the clot-lysing effectiveness of streptokinase produced from Streptococcus pyogenes EBL-48, emphasizing its low cost and ease of production. Streptokinase was produced using pre-optimized fermentation media and purified through ion exchange and gel-filtration chromatography. In vivo analysis involved inducing clots in a trial animal model using ferric chloride, comparing streptokinase with heparin. Ultrasonography assessed the clot-lysing activity of streptokinase. Streptokinase (47 kDa) effectively lysed clots, proving its low cost, easy production, and minimal adverse effects. Ultrasonography confirmed its fibrinolytic efficacy. These findings highlight potential as an affordable and easily produced thrombolytic agent, particularly relevant in resource-limited settings. Streptokinase efficacy and minimal adverse effects make it a promising option for thrombolytic therapy, especially in economically constrained regions. Future studies could optimize production techniques, explore different strains, and conduct clinical trials for human validation. Comparative studies with other thrombolytic agents would enhance understanding of their advantages and limitations.

CRISPR-Cas9 Mediated Knockout of SagD Gene for Overexpression of Streptokinase in Streptococcus equisimilis

Streptokinase is an enzyme that can break down the blood clots in some cases of myocardial infarction (heart attack), pulmonary embolism, and arterial thromboembolism. Demand for streptokinase is higher globally than production due to increased incidences of various heart conditions. The main source of streptokinase is various strains of Streptococci. Expression of streptokinase in native strain Streptococcus equisimilis is limited due to the SagD gene-mediated post-translational modification of streptolysin, an inhibitor of streptokinase expression through the degradation of FasX small RNA (through CoV/RS), which stabilizes streptokinase mRNA. In order to improve the stability of mRNA and increase the expression of streptokinase, which is inhibited by SagA, we used CRISPR-Cas9 to successfully knockout the SagD gene and observed a 13.58-fold increased expression of streptokinase at the transcript level and 1.48-fold higher expression at the protein level in the mutant strain compared to wild type. We have demonstrated the successful gene knockout of SagD using CRISPR-Cas9 in S. equisimilis, where an engineered strain can be further used for overexpression of streptokinase for therapeutic applications.

Antimicrobial Properties and Cytotoxic Effect of Imidazolium Geminis with Tunable Hydrophobicity

Antimicrobial, membranotropic and cytotoxic properties of dicationic imidazolium surfactants of n-s-n (Im) series with variable length of alkyl group (n = 8, 10, 12, 14, 16) and spacer fragment (s = 2, 3, 4) were explored and compared with monocationic analogues. Their activity against a representative range of Gram-positive and Gram-negative bacteria, and also fungi, is characterized. The relationship between the biological activity and the structural features of these compounds is revealed, with the hydrophobicity emphasized as a key factor. Among dicationic surfactants, decyl derivatives showed highest antimicrobial effect, while for monocationic analogues, the maximum activity is observed in the case of tetradecyl tail. The leading compounds are 2–4 times higher in activity compared to reference antibiotics and prove effective against resistant strains. It has been shown that the antimicrobial effect is not associated with the destruction of the cell membrane, but is due to specific interactions of surfactants and cell components. Importantly, they show strong selectivity for microorganism cells while being of low harm to healthy human cells, with a SI ranging from 30 to 100.

Fibrinolytic protease from Bacillus cereus S46: Purification, characterization, and evaluation of its in vitro thrombolytic potential

Intravascular thrombosis is a prime cause of cardiac complications worldwide. Microbial fibrinolytic proteases are of clinical significance in thrombosis treatment. The present study discusses the purification and characterization of a protease from Bacillus cereus S46, ascertaining its in vitro thrombolytic activity against a blood clot. By the three-step purification involving precipitation, dialysis, and diethylaminoethyl-cellulose ion-exchange chromatography, a 12.37-fold purification of the enzyme to homogeneity was achieved. The apparent molecular mass of the protease was 30 kDa, as found by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimum activity of the enzyme was observed at pH 8.0 and 40°C. The enzyme retained an 82.19% residual activity at pH 8.0 and 40°C for 1 h. The K_m and V_max values of the protease with casein were 0.0027 mM and 9.712 µmol/min, respectively. In an in vitro assay, the purified protease resulted in 97.02% lysis of the blood clot. The fibrinolytic potential of the enzyme, together with its characteristics of being active and stable under near-physiological conditions, may suggest its application as a therapeutic agent.

Phenotypic and genotypic methods for identification of slime layer production, efflux pump activity, and antimicrobial resistance genes as potential causes of the antimicrobial resistance of some mastitis pathogens from farms in Menoufia, Egypt

Mastitis caused by multi- or pan-drug resistant bacteria is a growing health concern. A total of 110 milk samples were collected: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Enterococcus faecalis, and Escherichia coli were present in 54/110 (49.09%), 37/110 (33.63%), 25/110 (22.72%), 7/110 (6.36%), and 50/110 (45.45%) samples, respectively. A total of 20 methicillin-resistant S. aureus (MRSA) isolates, 19 Streptococcus sp. isolates, and 15 E. coli isolates were selected, and 100% were positive for (coagulase and hemolysins), streptokinase, and hemolytic activity, respectively. A number of 11 E. coli isolates were serotyped, and the serotypes were: O26, O55, O111, O119, O124, O125, O127, and O158. The antimicrobial resistance index ranges for MRSA, Streptococcus sp., and E. coli were 0.49-0.83, 0.39-0.83, and 0.56-1, respectively. The most effective antimicrobials on Gram-positive isolates were cephradine, ciprofloxacin, doxycycline, norfloxacin, and vancomycin, while doxycycline and norfloxacin were effective on E. coli serotypes. All of the selected isolates exhibited slime layer production. The efflux pumps of the 12 MRSA, 12 Streptococcus sp., and 11 E. coli isolates exhibited activity with ethidium bromide concentrations of 1, 1.5, and 0.5 µg/ml, respectively. There was a simultaneous antimicrobial activity of the efflux pump inhibitor chlorpromazine with amoxicillin/clavulanic acid, erythromycin, and oxacillin, to which the isolates were resistant. The 12 MRSA isolates harboured the methicillin resistance genes mec(A,A1, and A2), mecA1, and mecC at frequencies of 9/12 (75%), 9/12 (75%), and 8/12 (66.7%), respectively, and the penicillin resistance gene BlaZ was present at a frequency of 5/12 (41.7%). The distributions of erm(A), erm(B), erm(C), erm(F), erm(G), and erm(Q) were 8/12 (66.7%), 5/12 (41.7%), 12/12 (100%), 2/12 (16.7%), 0/12 (0.0%), and 8/12 (66.7%), respectively. The 12 Streptococcus sp. isolates harboured mec(A, A1, and A2), mecA1, mecC, and blaZ at rates of 4/12 (33.33%), 4/12 (33.33%), 5/12 (41.7%), and 4/12 (33.33%), respectively. The frequencies of erm(A) and erm(F) were 4/12 (33.33%), and 9/12 (75%), respectively. The 11 E. coli isolates harboured the extended-spectrum β-lactamases integrase1, integrase2, blaCTX-M, blaCTX-M-1, and blaTEM at frequencies of 10/11 (90.90%), 11/11 (100%), 9/11 (81.81%), 6/11 (54.54%), and 10/11 (90.90%), respectively. Moreover, the frequencies of erm(A), erm(B), erm(C), erm(F), erm(G), and erm(Q) were 7/11 (63.63%), 4/11 (36.36%), 4/11 (36.36%), 5/11 (45.45%), 10/11 (90.90%), and 10/11 (90.90%), respectively. Our results demonstrated the high antimicrobial resistance of the investigated isolates and confirmed the existence of multiple mechanisms underlying multidrug resistance.