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1.
BMC Microbiol ; 8: 91, 2008 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-18544159

RESUMO

BACKGROUND: Pathogenic mycobacteria such as M. tuberculosis, M. bovis or M. leprae are characterised by their extremely slow growth rate which plays an important role in mycobacterial virulence and eradication of the bacteria. Various limiting factors influence the generation time of mycobacteria, and the mycobacterial DNA-binding protein 1 (MDP1) has also been implicated in growth regulation. Our strategy to investigate the role of MDP1 in mycobacterial growth consisted in the generation and characterisation of a M. bovis BCG derivative expressing a MDP1-antisense gene. RESULTS: The expression rate of the MDP1 protein in the recombinant M. bovis BCG containing the MDP1-antisense plasmid was reduced by about 50% compared to the reference strain M. bovis BCG containing the empty vector. In comparison to this reference strain, the recombinant M. bovis BCG grew faster in broth culture and reached higher cell masses in stationary phase. Likewise its intracellular growth in mouse and human macrophages was ameliorated. Bacterial clumping in broth culture was reduced by the antisense plasmid. The antisense plasmid increased the susceptibility of the bacteria towards Ampicillin. 2-D protein gels of bacteria maintained under oxygen-poor conditions demonstrated a reduction in the number and the intensity of many protein spots in the antisense strain compared to the reference strain. CONCLUSION: The MDP1 protein has a major impact on various growth characteristics of M. bovis BCG. It plays an important role in virulence-related traits such as aggregate formation and intracellular multiplication. Its impact on the protein expression in a low-oxygen atmosphere indicates a role in the adaptation to the hypoxic conditions present in the granuloma.


Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Ligação a DNA/metabolismo , Mycobacterium bovis/crescimento & desenvolvimento , Ampicilina/farmacologia , Animais , Proteínas de Bactérias/genética , Linhagem Celular , Proteínas de Ligação a DNA/genética , Expressão Gênica , Humanos , Macrófagos/microbiologia , Macrófagos/fisiologia , Camundongos , Mycobacterium bovis/efeitos dos fármacos , Mycobacterium bovis/genética , Mycobacterium bovis/metabolismo , Oligonucleotídeos Antissenso/genética , Oxigênio/metabolismo , Plasmídeos/genética
2.
Int J Antimicrob Agents ; 13(2): 133-5, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10595573

RESUMO

The resistance of mycobacteria to beta-lactam antibiotics is attributed to their ability to synthesize beta-lactamase. In our previous studies, beta-lactam/beta-lactamase-inhibitor combinations suppressed the growth of several mycobacteria in axenic cultures and ampicillin/sulbactam was bactericidal to Mycobacterium tuberculosis H37Rv in vitro, and to Mycobacterium leprae multiplying in mouse foot-pads. Since both these organisms multiply in phagocytic cells in the host, it is important to know whether the drug combination is active against mycobacteria multiplying in macrophages. We tested the action of ampicillin/sulbactam against four potentially pathogenic (to humans or to animals) mycobacteria, M. simiae, M. haemophilum, M. avium, M. microti, when phagocytosed by mouse macrophages. Bacteria were exposed to monolayers of peritoneal macrophages harvested from BALB/c mice. Unphagocytosed bacilli were removed and three concentrations of ampicillin/sulbactam were tested. Optimum activity was observed at 100 mg/l which killed 58-97% of the mycobacteria within macrophages, as determined by the CFU. beta-Lactam/beta-lactamase-inhibitors, especially ampicillin/sulbactam, might provide an effective alternative therapy against infections caused by mycobacteria resistant to other drugs.


Assuntos
Ampicilina/farmacologia , Inibidores Enzimáticos/farmacologia , Mycobacterium/efeitos dos fármacos , Penicilinas/farmacologia , Sulbactam/farmacologia , Inibidores de beta-Lactamases , Animais , Contagem de Colônia Microbiana , Interações Medicamentosas , Humanos , Técnicas In Vitro , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Mycobacterium/crescimento & desenvolvimento , Fagocitose
3.
J Antimicrob Chemother ; 44(2): 279-81, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10473236

RESUMO

We reported previously that an injectable form of ampicillin/sulbactam, Unasyn, was bactericidal to Mycobacterium leprae multiplying in mouse foot pads. In this study, we examined the effect of an orally active form of ampicillin/sulbactam, Sultamicillin, on the growth of M. leprae in mice. Three concentrations of the drug, mixed with the feed, were administered from the start until the mice were killed at 6 months; 0.01% of the drug inhibited bacterial growth by 54%, 0.10% by 74% and 0.20% by 93%. To test whether oral ampicillin/sulbactam was bactericidal, 0.50% of the drug, mixed with the feed, was administered to experimentally infected mice for 3 months during the logarithmic phase of bacterial growth, and then discontinued; multiplication of the bacilli was monitored monthly for the next 8 months. The results showed that orally active ampicillin/sulbactam is bactericidal to M. leprae.


Assuntos
Quimioterapia Combinada/farmacologia , Mycobacterium leprae/efeitos dos fármacos , Administração Oral , Ampicilina/administração & dosagem , Ampicilina/farmacologia , Animais , Quimioterapia Combinada/administração & dosagem , Membro Posterior/microbiologia , Hanseníase/tratamento farmacológico , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Modelos Biológicos , Mycobacterium leprae/crescimento & desenvolvimento , Sulbactam/administração & dosagem , Sulbactam/farmacologia
5.
Microbios ; 76(309): 251-61, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8302203

RESUMO

Mycobacterium tuberculosis and Mycobacterium leprae develop resistance against the drugs used to treat tuberculosis and leprosy, respectively. Now multidrug-resistant tuberculosis is spreading in many countries, especially with the emergence of AIDS. Multidrug treatment is being promoted at present to eradicate leprosy. Since M. leprae may also become multidrug-resistant, new approaches have to be adopted for controlling mycobacterial diseases. Mycobacteria usually synthesize beta-lactamase and are insensitive to beta-lactam antibiotics. M. tuberculosis contains a constitutive beta-lactamase; de-repression of beta-lactamase has been reported in M. leprae. Three different beta-lactam/beta-lactamase-inhibitor combinations (ampicillin/sulbactam, amoxicillin/clavulanate and piperacillin/tazobactam) were used to suppress the growth of several strains of mycobacteria (including M. tuberculosis H37Rv) in vitro. Ampicillin/sulbactam is a potent bactericidal agent against M. leprae multiplying in mouse foot pads. In the present work, ampicillin/sulbactam showed higher activity than the other drug combinations. The beta-lactam/beta-lactamase inhibitors are likely to be effective as rational therapeutic agents against mycobacterial infections.


Assuntos
Antibacterianos/farmacologia , Quimioterapia Combinada/farmacologia , Mycobacterium/efeitos dos fármacos , Inibidores de beta-Lactamases , Amoxicilina/farmacologia , Combinação Amoxicilina e Clavulanato de Potássio , Ampicilina/farmacologia , Animais , Ácidos Clavulânicos/farmacologia , Camundongos , Testes de Sensibilidade Microbiana , Mycobacterium/enzimologia , Mycobacterium/crescimento & desenvolvimento , Ácido Penicilânico/análogos & derivados , Ácido Penicilânico/farmacologia , Piperacilina/farmacologia , Combinação Piperacilina e Tazobactam , Sulbactam/farmacologia
6.
Microbios ; 72(291): 137-42, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1287401

RESUMO

The multiplication of Mycobacterium leprae in foot pads of experimentally-infected mice was suppressed by intramuscular administration of ampicillin combined with sulbactam or YTR-830H, two potent inhibitors of beta-lactamase in the bacteria. The antibiotic or the inhibitors by themselves were inactive. Ampicillin/sulbactam also inhibited the growth of drug-resistant M. leprae which grew in the presence of rifampin or dapsone. The finding provides a new approach to treat leprosy and to overcome drug resistance of the mycobacteria.


Assuntos
Ampicilina/farmacologia , Mycobacterium leprae/efeitos dos fármacos , Sulbactam/farmacologia , Animais , Resistência Microbiana a Medicamentos , Quimioterapia Combinada/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Mycobacterium leprae/crescimento & desenvolvimento
7.
Indian J Lepr ; 63(3-4): 410-7, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1666638

RESUMO

My first contact with Dr. Dharmendra was through correspondence. While working for Ph.D., I wrote to him that a section in his book "Notes on Leprosy" was ambiguous. Instead of ignoring the letter, he replied, agreeing to clarify it in the revised edition. I went to work at Carville at the invitation of Dr. Kirchheimer, who had seen my Ph.D. thesis. Dr. Dharmendra visited Carville to receive the Damien-Dutton award and stayed there for a few days. Carville is an isolated place with no public transportation. I used to take him for afternoon drives to the countryside around Carville. He published some of our papers in Leprosy in India and later in Indian Journal of Leprosy. He was very prompt in acknowledging receipt of manuscripts and suggesting any changes to be made. He also reprinted in the Journal several of our papers published elsewhere, and also a lecture I gave at a meeting of the Japanese Leprosy Association. During one of my visits to India, Dr. M. C. Vaidya had arranged a talk by me at the All India Institute of Medical Sciences, New Delhi. At the invitation of Dr. Dharmendra, I visited him in his home. We used to exchange new year cards and letters. He wrote to me about his eye infection and consequent loss of sight in one eye. He asked me to write an editorial for an issue of Indian Journal of Leprosy (January 1989). The last time I met him was during the International Leprosy Congress held in New Delhi.


Assuntos
Mycobacterium leprae/enzimologia , Ampicilina/farmacologia , Animais , Glutamato Descarboxilase/metabolismo , Humanos , Hanseníase/tratamento farmacológico , Monofenol Mono-Oxigenase/metabolismo , Mycobacterium leprae/crescimento & desenvolvimento , Ácido Penicilânico/farmacologia , Tazobactam , Inibidores de beta-Lactamases , beta-Lactamases/metabolismo
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