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PubMed2004

[Emerging rickettsioses].

Ticks are known to carry and transmit a number of microbial agents that cause diseases in humans and animals. Among these are members of the order Rickettsiales (alpha-proteobacteria), which include the genera Rickettsia and Ehrlichia. The most common and well-known Rickettsial human disease in Europe is Mediterranean Spotted Fever (MSF), caused by Rickettsia conorii. In recent years, a number of new Rickettsia species have been discovered in Europe, some of which have been shown to be pathogenic to humans. These discoveries have been facilitated by use of sequence-based molecular identification techniques. In Italy, it is generally believed that R. conorii is the only Rickettsia species present, and clinical tests for MSF rely on antigens raised against this bacterium. We are currently undertaking a molecular screening study of Rickettsiales-bacteria in ticks from various regions of Italy, to check for the potential presence of species from this order recently discovered in other parts of Europe. So far, we have identified a number of additional species in ticks collected from northern, central and southern regions. These include the known pathogens R. helvetica and R. slovaca as well as two species which may or may not be of medical relevance: R. monacensis and R. sp. IRS4. As a part of this survey, we have identified a novel alphaproteobacterium from the medically important tick Ixodes ricinus. This bacterium, tentatively named IricES1, has the unusual property of existing within the mitochondria, as well as the cytoplasm, of ovarian cells. To our knowledge, this is the only known example of a bacterium that is able to enter the mitochondria of animals. Our recently published electron microscopic data indicates that the bacterium enters mitochondria between the inner and outer membranes, and then proceeds to consume the inner mitochondrial matrix. We will present further data on this bacterium, including: 1) its phylogenetic position based on various molecular sequences, 2) its localization within the tick based on in situ hybridization; 3) its distribution among tick populations in Europe; 4) preliminary data on attempts at culturing this bacterium in a variety of cell types. Possible interactions between the bacterium and its host will be discussed. Ticks are known to carry and transmit a number of microbial agents that cause diseases in humans and animals. Among these are members of the order Rickettsiales (alpha-proteobacteria), which include the genera Rickettsia and Ehrlichia. The most common and well-known Rickettsial human disease in Europe is Mediterranean Spotted Fever (MSF), caused by Rickettsia conorii. In recent years, a number of new Rickettsia species have been discovered in Europe, some of which have been shown to be pathogenic to humans. These discoveries have been facilitated by use of sequence-based molecular identification techniques. In Italy, it is generally believed that R. conorii is the only Rickettsia species present, and clinical tests for MSF rely on antigens raised against this bacterium. We are currently undertaking a molecular screening study of Rickettsiales-bacteria in ticks from various regions of Italy, to check for the potential presence of species from this order recently discovered in other parts of Europe. So far, we have identified a number of additional species in ticks collected from northern, central and southern regions. These include the known pathogens R. helvetica and R. slovaca as well as two species which may or may not be of medical relevance: R. monacensis and R. sp. IRS4. As a part of this survey, we have identified a novel alphaproteobacterium from the medically important tick Ixodes ricinus. This bacterium, tentatively named IricES1, has the unusual property of existing within the mitochondria, as well as the cytoplasm, of ovarian cells. To our knowledge, this is the only known example of a bacterium that is able to enter the mitochondria of animals. Our recently published electron microscopic data indicates that the bacterium enters mitochondria between the inner and outer membranes, and then proceeds to consume the inner mitochondrial matrix. We will present further data on this bacterium, including: 1) its phylogenetic position based on various molecular sequences, 2) its localization within the tick based on in situ hybridization; 3) its distribution among tick populations in Europe; 4) preliminary data on attempts at culturing this bacterium in a variety of cell types. Possible interactions between the bacterium and its host will be discussed.

Animals↗
PubMed1989

Development of local morphological changes after intradermal inoculation of Q-fever chemovaccine.

Development of morphological changes was studied in the site of intradermal inoculation of Q-fever chemovaccine. The chemovaccine was obtained by trichloroacetic acid extraction from Coxiella burnetii, strain Nine mile, phase I cells. The effect of two vaccine doses (0.2 mg and 1.0 mg) was compared in two groups of guinea pigs (each consisting of 21 animals). After inoculation of 1.0 mg vaccine abscesses formed in the dermis and in subcutaneous tissue along with dystrophic changes of skeletal muscles. Reparation of these lesions progressed sufficiently slowly and was not completed before 60 days after vaccine inoculation. The regeneration of skeletal muscles was of budding type. After inoculation of 0.2 mg of chemovaccine minimal lesions occurred in the subcutaneous tissue only. However, already within 48 hr this vaccine dose evoked a strong reparation response. Interesting was the finding of Kurloff cells in the haemorrhagic foci. The results suggest that the low-reactogenic chemovaccine dose of 0.2 mg might be sufficiently immunogenic after subcutaneous administration.

Abscess↗
PubMed2001

New uses of older antibiotics.

Despite the development of extended-spectrum penicillins, cephalosporins, and quinolones, the older antimicrobial agents, doxycycline, minocycline, TMP-SMX, clindamycin, and metronidazole, still play an important role in the treatment of infectious diseases. All of these older drugs are well absorbed by the oral route, attaining serum levels equivalent to those achieved by parenteral administration. The availability of generic forms of the older drugs reduces their cost. Besides traditional uses, some older drugs have become the preferred therapy for newly recognized infectious diseases. Doxycycline is the preferred drug for rickettsial tickborne diseases, ehrlichiosis and early Lyme disease. TMP-SMX is the preferred drug for I. belli and Cyclospora. Minocycline has been used to treat MRSA and MRSE infections. Clindamycin or metronidazole combined with a quinolone is an excellent oral regimen for polymicrobial infections. [table: see text]

Anti-Bacterial Agents↗
PubMed1950

Infectious diseases.

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Anti-Bacterial Agents↗