FEMS Microbiol Lett. 1989 Jul 1;51(1):21-4.
Effects of tetracyclines on the production of extracellular proteins by members of the propionibacteriaceae.

Chopra I, Hacker K.

Department of Microbiology, Medical School, University of Bristol, U.K.

The effect of tetracyclines on the synthesis of proteins in Propionibacterium avidum and P. acnes was examined. Synthesis of an extracellular lipase by P. avidum was slightly more sensitive to inhibition by tetracycline than total (cellular and extracellular) protein synthesis. The effect of tetracycline and other analogues on the synthesis of secreted proteins was also examined in P. avidum and P. acnes by protein radiolabelling experiments. In all cases the synthesis of secreted proteins was only about 2-fold more sensitive to inhibition by tetracyclines than total protein synthesis. These results contrast with previously published findings in Escherichia coli which show that synthesis of secreted proteins is highly susceptible to inhibition by tetracycline. The implications of these findings in relation to inhibition of membrane bound ribosomes by tetracyclines are discussed.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2792736&dopt=Abstract antibiotics, tetracycline




J Bacteriol. 1988 Apr;170(4):1423-9.
Characterization of a novel tetracycline resistance that functions only in aerobically grown Escherichia coli.

Speer BS, Salyers AA.

Department of Microbiology, University of Illinois, Urbana 61801.

A tetracycline resistance (Tcr) gene that was found originally on two Bacteroides plasmids (pBF4 and pCP1) confers tetracycline resistance on Escherichia coli, but only when it is grown aerobically. Using maxicells, we have identified a 44-kilodalton protein which is encoded by the region that carries the Tcr gene and which may be the Tcr gene product. Localization experiments indicate that this 44-kilodalton protein is cytoplasmic. To determine whether the tetracycline resistance gene is expressed under anaerobic conditions, we have constructed a protein fusion between the Tcr gene and lacZ. In strains of E. coli carrying the fusion, beta-galactosidase activity was the same when the cells were grown under anaerobic conditions as when the cells were grown under aerobic conditions. This indicates that the tetracycline resistance gene product is made under anaerobic conditions but does not work. The failure of the Tcr protein to function under anaerobic conditions was not due to a requirement for function of the anaerobic electron transport system, because neither nitrate nor fumarate added to anaerobic media restored tetracycline resistance. Inhibition of the aerobic electron transport system with potassium cyanide did not prevent growth on tetracycline of cells containing the Tcr gene. A heme-deficient mutant, E. coli SHSP19, which carries the Tcr gene, was still resistant to tetracycline even when grown in heme-free medium. These results indicate that functioning of the Tcr gene product is not dependent on the aerobic electron transport system. Thus the requirement for aerobic conditions appears to reflect a requirement for oxygen. Spent medium from an E. coli strain carrying the Tcr gene, which was grown in medium containing tetracycline (50 micrograms/ml), did not inhibit growth of a tetracycline-susceptible strain of E. coli. Thus, the Tcr gene product may be detoxifying tetracycline.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2832361&dopt=Abstract antibiotics, tetracycline




JAMA. 1977 May 9;237(19):2069-74.
Prescribing of tetracycline to children less than 8 years old. A two-year epidemiologic study among ambulatory Tennessee medicaid recipients.

Ray WA, Federspiel CF, Schaffner W.

The committee on Drugs of the American Academy of Pediatrics finds virtually no indications for administering tetracyclines to children less than 8 years old. This study analyzes tetracycline prescribing to ambulatory children less than 8 years of age in the Tennessee Medicaid program during a two-year period. Of the nearly 59,000 children in the study, 4,026 (7%) received 7,046 tetracycline prescriptions. Twenty-seven percent (527) of 1,947 participating physicians prescribed tetracycline; 26 physicians (5%) wrote 54% of the prescriptions for 45% of the children. Physicians in family practice prescribed the greatest quantity of tetracycline. Surgeons and internists prescribed more tetracycline to young children than did pediatricians. Rural location of practice was independently associated with increased tetracycline prescribing for all specialties. Recent graduates from medical school were less apt to prescribe tetracycline than were earlier graduates.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=323518&dopt=Abstract antibiotics, tetracycline




Antibiotiki. 1977 May;22(5):455-7.
[Action of tetracyclines on the pseudotuberculosis microbe in vitro experiments and their effectiveness in experimental pseudotuberculosis in white mice]

[Article in Russian]

Rogozina MI, Gurleva GG, Ryzhko V, Makarovskaia LN, Pun'ko TA.

227 out of 228 strains of pseudotuberculosis microbes studied in vitro proved to be sensitive to tetracyclines. The MIC of tetracycline and morphocycline ranged within 0.25--25 gamma/ml. The MIC of chlortetracycline and oxytetracycline was somewhat lower, i. e. 1--50 gamma/ml. When administered intramuscularly all the tetracyclines had pronounced therapeutic effect in experiments with albino mice infected with the antibiotic sensitive strains of J. pseudotuberculosis. Chlortetracycline proved to be the most active drug in treatment of albino mice per os.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=327916&dopt=Abstract antibiotics, tetracycline




J Oral Maxillofac Surg. 1987 Oct;45(10):866-72.
Connective tissue reactions to 3% tetracycline ointment in rat skin.

Eslami A, Van Swol RL, Sadeghi EM.

Department of Periodontics, Marquette University School of Dentistry, Milwaukee, WI 53233.

The connective tissue reactions to 3% tetracycline ointment were studied in 14 Sprague-Dawley white male rats. Using polyethylene tubes, the ointment was implanted subcutaneously in the pouches surgically created on the backs of the experimental group. Empty tube implants, tubes with the vehicle (vaseline/lanolin), and a sham operation (surgical pouches with no implant) served as controls. The animals were killed on day 14 and tissue blocks were taken containing the tubes and a generous amount of the peripheral connective tissue. The connective tissue surrounding the tube opening furthest from the surgical incision was histologically examined for the severity of tissue reaction (STR), the number of inflammatory cell infiltrates (II), and the spread of the reaction area (RSI). The data were statistically analyzed. The sham operation group showed minimal inflammatory response. All three parameters (STR, II, RSI) were significantly greater in the tetracycline group when compared with the empty tube group at 0.05 level of significance. There were significant differences between the mean values of the STR and RSI scores in the tetracycline and vehicle groups (groups 1 and 2). The vehicle group (group 2) had significantly higher STR and II values than the empty tube group (group 3); however, the RSI scores were not statistically different. Necrosis was observed in the reaction site in group 1 and vacuole-containing macrophages were noted in groups 1 and 2. This study, although an animal investigation, questions the use of topical 3% tetracycline ointment on sutured surgical flaps.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3477622&dopt=Abstract antibiotics, tetracycline




Vet Rec. 1986 Aug 2;119(5):108-12.
The synergistic activity of tiamulin and chlortetracycline: in-feed treatment of bacterially complicated enzootic pneumonia in fattening pigs.

Burch DG, Jones GT, Heard TW, Tuck RE.

The antibacterial effects of a combination of tiamulin and chlortetracycline in vitro against a number of field isolates of Pasteurella multocida, Haemophilus pleuropneumoniae and Bordetella bronchiseptica were examined. There was a marked synergism between the two antibiotics against all eight isolates of P multocida, against seven of nine isolates of H pleuropneumoniae and against the single strain of B bronchiseptica tested. Two field trials were carried out on a herd with a history of complicated enzootic pneumonia where the presence of Mycoplasma hyopneumoniae and P multocida had been established and subsequently the presence of H pleuropneumoniae was discovered. Feed containing tiamulin at 100 ppm combined with chlortetracycline at 300 ppm was given for seven days to pigs affected with pneumonia, and the results were compared with untreated controls and pigs receiving chlortetracycline at 300 ppm. There was a follow-up observation period of three weeks when all groups received unmedicated feed. During the medication period the combination treated groups showed a statistically significant increase in average daily weight gain of 156 g (20.4 per cent) and in feed conversion efficiency of 0.576 (20.8 per cent) and a numerical improvement in average disease score in comparison with the untreated controls. These improvements were approximately double those observed in the groups treated with 300 ppm chlortetracycline which showed improvements of 93 g (12.2 per cent) in average daily gain and 0.301 (10.9 per cent) in feed conversion efficiency. During the following three weeks most of the initial gains were lost, probably owing to the reinfection of the treated groups by the untreated controls.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3750792&dopt=Abstract antibiotics, tetracycline




Antibiotiki. 1975 Aug;20(8):714-7.
[Sensitivity to doxycycline (vibramycin) of the microflora isolated from the patients in a therapeutic clinic]

[Article in Russian]

Tydel'skaia IL, Ptukha RM, Iakovenko SN, Sidorenko RA.

Sensitivity of microflora to tetracycline, oxytetracycline, chlortetracycline and doxycicline was studied. A total of 237 pure cultures of Strep. viridans (54), beta-hemolytic streptococci (27), pathogenic staphylococci (52), non-pathogenic staphylococci (53) and Coli bacteria (51) were tested with the agar-diffusion method using standard discs. Doxycicline was most active and chortetracycline was least active. The maximum sensitivity to doxycicline was found in beta-hemolytic streptococci (85.4%) and the minimum sensitivity to that antibiotic was found in Coli bacteria (39.2%) and Strep. viridans (35.6%), which was superior to that with respect to the other tetracyclines. Coincidence of the clinical effect with the microflora sensitivity and high percentage of sensitivity to doxycicline among Staph. aureus, which is important in treatment of severe infections caused by the organism were observed.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=779626&dopt=Abstract antibiotics, tetracycline




Tropenmed Parasitol. 1977 Dec;28(4):513-20.
The use of tetracyclines on the chemotherapy of experimental East Coast Fever (theileria parva infection of cattle).

Brown CG, Radley DE, Burridge MJ, Cunningham MP.

In a series of experiments, groups of cattle, undergoing patent East Coast fever (ECF) reactions induced by the inoculation of tick-derived stabilates of Theileria parva infective particles, were treated by parenteral administration of 2 tetracyclines. Ten cattle were treated with n-pyrrolidinomethyl tetracycline at 15 mg/kg for 5 days, starting on the first day macroschizonts were detected in lymph node biopsy smears. Nine of these treated cattle survived ECF reactions induced by an inoculum which killed 7 of 10 untreated controls. The same tetracycline, at 10 mg/kg daily for 5 days from the first day of febrile response had no effect on the disease. Oxytetracycline was administered at 15 mg/kg daily for 5 days to 2 groups of cattle infected with ECF. All 5 cattle survived which were treated on the first day parasites were seen. Four of 5 survived in which treatment was delayed till the onset of febrile response. All 5 untreated controls in this experiment died.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=414390&dopt=Abstract antibiotics, tetracycline




J Antimicrob Chemother. 1992 Sep;30(3):303-11.
Inhibition of Chlamydia trachomatis growth in mouse fibroblasts by liposome-encapsulated tetracycline.

al-Awadhi H, Stokes GV, Reich M.

Department of Microbiology and Immunology, George Washington University Medical Center, DC 20037.

The in-vitro susceptibility of Chlamydia trachomatis to liposome-encapsulated tetracycline was determined and compared with free tetracycline. Anionic, cationic and neutral small unilamellar liposomes were used in this study. Chlamydia-infected mouse fibroblast monolayers were continuously exposed to varying concentrations of antibiotic, incubated for 48 h and Giemsa stained. The minimum inhibitory concentration (MIC) for anionic, cationic and neutral liposomes containing tetracycline were 0.38, 0.08 and 0.04 mg/L, respectively. This was approximately 2, 10, and 20 times more efficient than free tetracycline (MIC, 0.79 mg/L). Neutral liposomes displayed no visible toxic side-effects on the host cells. When compared with free tetracycline, neutral liposomes were the most efficient for the delivery of inhibitory concentrations of tetracycline to chlamydia-infected mouse fibroblast L cell cultures.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1452495&dopt=Abstract antibiotics, tetracycline