Insilico identification of Lyme disease
Chapter 3
3. Results
3.1. Determination of MIC and MBC values
The in vitro susceptibility of these drugs to the three Bb strains CA8, JLB31, and NP40 was evaluated using the BacTiterGlo Assay and microscopy. Based on the discovered MICs, the in vitro effectiveness of the studied drugs for the NP40 strain of Bb was graded as follows: cefoxitin (MIC: 1.25 M/mL), cefamandole (MIC: 2.5 M/L), cefuroxime (MIC: 5 M/L), and cefapirin (MIC: 10 M/L). Also, the in vitro efficacies of tested molecules for other two strains are as follows, for CA8 strain of Bb: cefoxitin (MIC: 0.625 µM/mL) .cefuroxime (MIC: 1.25 µM/mL), .cefamandole (MIC: 1.25 µM/mL) .cefapirin (MIC:5.0 µM/mL) and for JLB31 strain of Bb: cefoxitin (MIC: 0.625 µM/mL) .cefuroxime (MIC: 1.25 µM/mL), .cefamandole (MIC: 1.25 µM/mL) .cefapirin (MIC: 2.5 µM/mL). These results showed that the JLB31 and CA8 strains were more sensitive to cefoxitin than the NP40 strain (MIC: 1.25 M/mL). As shown in Figure 1, the BacTiter-Glo Assay was used to assess the efficacy of the tested medications, cephalosporins. We determined the MBC of each tested cephalosporin in a similar way. The MBC values for cefoxitin and cefuroxime were both #10 M. Cefamondole has an MBC value of #20 M. NP40 has a very high MBC value for cefapirin (.160 M), compared to other strains where it was only #20 M. The MIC and MBC values of the drugs tested against the three Bb strains are shown in Table 1. In our laboratory evaluation of these cephalosporins, cefoxitin was shown to be the compound with the highest potency.
Table 2: Protein name and their Pdb I. D.
Protein name Pdb I.D Cefamandole Cefapirin Cefoxitin Cefuroxime
secA subunit PBP Ab initio -8.4 -7.9 -7.2 -8.2
OspE 2M4F -7.1 -6.2 -7.3 -7.2
3.2. In vivo testing of drugs
Working5 to 6 weeks were used to investigate the effectiveness of the medicines cefoxitin and gambogic acid. After receiving 1 105 Bb via the intradermal method one week prior, mice were given cefoxitin once daily for five days. The heart, urinary bladder, and other organs were removed from the dead mice and placed in BSK-II medium. All of the mice given cefoxitin treatment had no detectable Bb in their heart, urinary bladder, or ear tissue samples. At 20 mg/kg, cefoxitin eradicated the infection in all the animals (Table 2). No borrelial growth was seen in ceftriaxone, which was employed as a positive control. In non-drug treated control saline samples, Bb growth was seen. the effectiveness of the medications put to in-vivo test.
3.3. Insilico analysis of cephalosporins binding to PBPs and Osps
The ability of the candidate compounds to bind to the Bb proteins was ascertained using computational research. According to earlier research, -lactam antibiotics bind covalently with PBPs and Osps and work to kill bacteria by obstructing the final stage of cell wall formation. We conducted binding experiments between the cephalosporin medications cefamandole, cefapirin, cefoxitin, and cefuroxime and SecA subunit PBP and OspE on the basis of these earlier investigations. The four cephalosporins' PBP and OspE docking scores, or binding affinities. Cefamandole, out of all the pharmaceutical compounds studied, had the greatest binding affinity (-8.4 kcal/mol) for the SecA subunit PBP of Bb, according to a molecular docking study. The average binding affinity values for the test compounds were substantially lower (-7.9 kcal/mol) than they were for the other Borrelia proteins. Cefoxitin exhibited a significant binding affinity for PBP of -7.2 kcal/mol when tested on mice and was shown to be effective. It shows a strong hydrogen bonding at amino acid Arg138 of Borrelia PBP with an intermolecular distance of less than 5, showing a significant preference for this protein. It may also produce interactions such as 9 Van der Waals, Pi Stacking, and Alkyl type. Other drugs, including cefapirin (-7.9 kcal/mol) and cefuroxime (-8.2 kcal/mol), effectively interacted with the drug-binding pockets of the PBP of Borrelia with no statistically significant difference in the findings. The four PBP-containing cephalosporins are grouped in a spatial and linear arrangement. All of the expected interactions between PBP and cephalosporins.
Table 3: Compounds and their binding ability
| Compound | Binding ability | Hydrogen bond | Van der waals | Alkyl |
|---|---|---|---|---|
| Cefamandole | -8.4 | Tyr 193,lle676 | Glu 524,Ser 489,Thr 515 | Arg 765,Tyr 766 |
| Cefapirin | -7.9 | Lys 374,Arg 35,His 358 | Gly 350,Ala 781,Ser489 | Glu 230,Arg 352 |
| Cefoxitin | -7.2 | Arg I 38 | Glu 524,Ser 489,Thr 515 | Trp 142,Ala496 |
| Cefuroxime | -8.2 | Lle523,Asn522 | Glu524,Tyr 134 | Glu 524,Ser 489,Thr 515; Phe 493,Arg 138,Ala492 |
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Figure: Interacting compounds that screened by PyRx and visualizes by using discovery studio
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Figure: 2D Structures of Interacting compounds.
Discussions
Based on the outcomes of our high-throughput screening, we have selected four cephalosporins for this study: cefoxitin, cefamandole, cefuroxime, and cefapirin. Three Bb s.s. strains (CA8, JLB31, and NP40) were tested in this investigation for their in vitro susceptibility to cephalosporins, which was done for the first time that we are aware of. Numerous groups have done substantial research on microdilution.
Using a similar approach, we evaluated cephalosporins, and cefoxitin, a second-generation cephalosporin, was found to be one of the most efficient drugs that significantly reduced the production of Borrelia's cell walls. The spread of the spirochete was also successfully halted by cefamandole, cefapirin, and cefuroxime. The MBC for the Bb strain NP40 for the antibiotic cefapirin was more than 160 M. Cefapirin's reduced in vitro activity as a result of the unstable -lactam ring, which results in decreasing concentrations over time, might be one of the potential explanations of a high MBC.
A wide range of infections brought on by both anaerobic bacteria and Gram-positive or -negative aerobes can be treated with cefoxitin, a broad-spectrum antibiotic. Many infections, including intra-abdominal infections, infections of the lower respiratory tract, infections of the urinary tract and gonococci, infections of the skin and soft tissues, infections of the bones and joints, and bacteremia are treated with cefoxitin. The effectiveness of an antibiotic to eradicate Bb depends on a number of factors, and since there are no clinical standards for the management of chronic borreliosis, our findings are extremely important and call for additional investigation, including in vivo efficacy trials. Both in vitro and in vivo testing revealed that a variety of cephalosporins were quite successful at getting rid of Borrelia. Cephalosporins, which act on the bacterial cell membrane and block the formation of peptidoglycan, are very similar to penicillins and likewise include a -lactam ring.
One of the crucial prokaryotic membrane proteins found in both Gram-positive and -negative bacteria is called 17PBP. PBPs are cytoplasmic membrane-associated enzymes that catalyse terminal processes during the manufacture of peptidoglycan in Borrelia, just like they do in other bacteria.
With a better understanding of the interactions between compounds and proteins as a result of this study, it will be easier to identify new targets to help eradicate the borrelia infection. The findings of this study can contribute to mechanistic and translational research and be used to develop clinically effective treatments for Lyme disease.
Conclusions
In conclusion, diphtheria vaccines now available are successfully preventing serious illness in young children, but new methods are required to stop its comeback. Increasing the memory response's duration and preventing asymptomatic transmission are currently considered to be significant qualities of a drastically enhanced vaccine. Using microdilution techniques, we assessed the in vitro susceptibility of four medicines to three different Bb strains (CA8, JLB31, and NP40). Cefoxitin (1.25 M/mL) demonstrated minimal MIC and MBC values. At 20 mg/kg, cefoxitin efficiently eradicated the Bb infection in the C3H/HeN mouse model. We have demonstrated the binding affinities of four cephalosporins through the use of two Bb enzymes (PBP and OspE) using in silico analysis. All cephalosporins have a higher binding affinity for the SecA subunit PBP, which has the potential to be researched as a potent therapeutic target. We are currently conducting extensive research to demonstrate this potential use of the four cephalosporins we considered in our study.