Drug resistant

Badger, J., et al. Three-dimensional structures of drug-resistant mutants of human rhinovirus 14. /. Mol. Biol. 

Infectious patients present a difficult challenge when trying to protect health care workers. These patients must be isolated from the health care workers as well as from the other patients in the hospital. Special isolation rooms are used for this purpose. These rooms are generally used for isolation of infectious tuberculosis (TB) patients, but could be used for patients with other airborne-transmitted diseases. In the United States, there were 22 812 new cases of tuberculosis in 1993, equal to 8.7 per 100 000 population. This represents a 2.8% increase since 1985, following a 6-7% annual decline from 1981-1984.Several studies have documented higher than expected tuberculin skin test (TST) conversion rates in hospital personnel.The National Institute for Occupational Safety and Health " reports that multiple-drug-resistant (MDR) strains of TB have been reported in 40 states and have caused outbreaks in at least 21 hospitals, with 18-35% of exposed workers having documented TST conversions. 

Acquired resistance has been observed by constitutive upregulation of mdr efflux pump expression due to a mutation inactivating a respective repressor or inducibly, caused by molecules transiently inactivating repressor molecules upon binding. Depending upon the substrate spectra of the respective subset of efflux pumps upregulated, a multiple drug resistance (mdr) phenotype is expressed, which in combination with a specific resistance mechanism can contribute to a clinically relevant level of resistance. 

Li X-Z, Nikaido H (2004) Efflux-mediated drug resistance in bacteria. Drugs 64 159-204... 

Szakacs G, Paterson JK, Ludwig JA et al (2006) Targeting multi drug resistance in cancer. Nat Rev Drag Discov 5 219-234... 

Drug resistance in the defined sense, however, is not always the reason for treatment failures. The formation of biofilms may be as well regarded as a resistance mechanism. Cells within such a film withstand the antibiotic treatment. Some antibiotics (e.g. the aminoglycoside tobramycin) penetrate only slowly into the film. A further explanation is the existence of cells living in a non-growing, protected phenotypic state. 

Ribosomal Protein Synthesis Inhibitors. Figure 5 Nucleotides at the binding sites of chloramphenicol, erythromycin and clindamycin at the peptidyl transferase center. The nucleotides that are within 4.4 A of the antibiotics chloramphenicol, erythromycin and clindamycin in 50S-antibiotic complexes are indicated with the letters C, E, and L, respectively, on the secondary structure of the peptidyl transferase loop region of 23S rRNA (the sequence shown is that of E. coll). The sites of drug resistance in one or more peptidyl transferase antibiotics due to base changes (solid circles) and lack of modification (solid square) are indicated. Nucleotides that display altered chemical reactivity in the presence of one or more peptidyl transferase antibiotics are boxed. 

Because the natural penicillins have been used for many years, drug-resistant strains of microorganisms have developed, making the natural penicillins less effective than some of the newer antibiotics in treating a broad range of infections. Bacterial resistance has occurred within tire penicillins. Bacterial resistance is the ability of bacteria to produce substances that inactivate or destroy the penicillin. One example of bacterial resistance is tiie ability of certain bacteria to produce penicillinase, an enzyme that inactivates penicillin. The penicillinase-resistant penicillins were developed to combat this problem. 

Tuberculosis caused by drug-resistant organisms should be considered in patients who have no response to therapy and in patients who have been treated in the past... 

Kioka, N., Hosokawa, N., Komano, T., Hiiayoshi, H., Nagat, K., Ueda, K. (1992). Quercetin, a bioflavonoid, inhibits the increase of human multi-drug resistance gene (MDRI) expression caused by arsenite. FEES Lett. 301, 307-309. 

Kawaguchi, H. Hiroshi Drug Action Drug Resist. Bact. (DADRBY) 2, 45 (1975). 

Lee EJ, Kantor R, Zijenah L, Sheldon W, Emel L, Mateta P, Johnston E, Wells J, Shetty AK, Coovadia H et al. (2005) Breast-mUk shedding of drug-resistant HIV-1 subtype C in women exposed to single-dose nevirapine. J Infect Dis 192 1260-1264... 

Deval J, D Abramo CM, GOtte M (2006) Selective excision of non-obUgate chain-terminators by the hepatitis C virus NS5B polymerase. In 16th international HIV Drug Resistance workshop, Sitges, Spain, June 13-17, 2006. Antivir Ther 11 Suppl 1 S3 (abstract no 1)... 

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