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T Benish

Publications and source records attributed to T Benish.

3 recordsLinked to original sources
PubMed2001

Synthesis and analysis of ethylated tetracycline, an antibiotic derivative that inhibits the growth of tetracycline-resistant XL1-Blue bacteria.

Bacterial resistance to antibiotics is a significant problem in medical care facilities, causing increased fatalities due to infection. The present study demonstrates that antibiotic structures can be selectively altered in a manner that revives their ability to inhibit bacterial growth. The antibiotic tetracycline was ethylated at the position of the phenolic hydroxy group with the use of diazoethane, forming an ethyl ether functional group. This derivative was dissolved in Luria-Bertani (LB) agar medium, then placed in tissue culture for screening against a tetracycline-resistant bacterial strain. The growth of this bacterial strain, designated XL1-Blue, was inhibited by the ethylated form of tetracycline. The procedure for synthesizing ethylated tetracycline utilizes diazoethane and is presented with the molecular structures and IR spectra. The ethylated form of tetracycline was stable at -20 degrees C for many weeks, and was soluble in LB agar plate medium. Ethylated tetracycline induced growth inhibition of XL1-Blue bacteria within the first 24 h of incubation. The level of bacterial growth inhibition was greater than 30%. Calculation of the partition coefficient, log P, was accomplished and indicates that ethylated tetracycline has an increased lipophilic tendency relative to unmodified tetracycline, and therefore has greater solubility in lipid bilayers.

Acetates↗
PubMed2000

Modified antibiotics-methylated ampicillin and ethylated ampicillin-inhibit growth of ampicillin-resistant strain of bacteria.

Bacterial resistance to antibiotics is a significant problem in health facilities and results in higher costs for health care and increased fatalities due to infection. The work presented here suggests that antibiotic molecular structure can be altered in a selected manner, which will revive the bacterial growth inhibiting capability. A bacterial strain PKK3535(DH1), which is resistant to the antibiotic ampicillin, was found to be highly growth inhibited by these altered forms of ampicillin when tested in tissue culture. The level of growth inhibition of bacterial strain PKK3535(DHI) was greater than 50%, for both molecular variants of ampicillin that were investigated. The bacteria strain used for testing was a clinical isolate obtained from the University Hospital of the University of Nebraska, Omaha. These two antibiotic variants were methylated ampicillin and ethylated ampicillin. The synthetic procedure for generating these variants is presented as well as the molecular structure. The methylated and ethylated ampicillin were found to be stable at 0 degrees C for many weeks, were somewhat less soluble than normal ampicillin, but dissolved in LB plate media. The resistant bacteria strain was plated onto LB media with altered ampicillin and profound inhibition of bacteria growth was seen within the first 24 hours of incubation. These molecular variants of ampicillin provide evidence of a means to combat the proliferation of resistant bacterial strains. The molecular alteration of antibiotics may provide a suitable means to study and combat the appearance of antibiotic-resistant bacteria.

Ampicillin↗