Rickettsia is a genus of nonmotile, Gram-poor, nonspore-forming, enormously pleomorphic bacteria that can exist as cocci (zero.1 μm in diameter), rods (1–four μm long), or thread-like (10 μm long). Being obligate intracellular parasites, the Rickettsia survival relies upon on entry, growth, and replication inside the cytoplasm of eukaryotic host cells. Rickettsiae include a set of microorganisms that phylogenetically occupy a function between bacteria and viruses. The genus Rickettsia is blanketed inside the bacterial tribeRickettsiae, own family Rickettsiaceae, and order Rickettsiales. They may be obligate intracellular gram-bad coccobacillary bureaucracy that multiplies inside eukaryotic cells. Rickettsiae do now not stain well with Gram stain, however they tackle a feature red shade when stained by means of the Giemsa or Gimenez stain. They have usual gram-bad cellular walls and lack flagella. Their genome is very small, composed of 1-1.5 million bases.
Treatment of patients with feasible rickettsioses must be commenced early and ought to never watch for confirmatory testing, which may also take weeks while serology is used. Instantaneous empiric treatment with a tetracycline is recommended, maximum generally doxycycline. Extensive-spectrum antibiotics are not generally helpful. Chloramphenicol can be an opportunity in some cases, but its use is associated with greater deaths, specifically for R. rickettsii. Expert advice must be sought if opportunity agents are being considered.
In Australia, 3 cases of spotted fever group rickettsial infection in residents of northern Queensland, Australia, who had unusually severe clinical manifestations. Complications included renal failure, purpura fulminans, and severe pneumonia. Clinical illness caused by Rickettsia australis may not be as benign as previously described.