Ehrlichia chaffeensis infections among HIV-infected patients in a human monocytic ehrlichiosis-endemic area

Seroprevalence of six pathogens transmitted by the Ixodes ricinus ticks in asymptomatic individuals with HIV infection and in blood donors

The objective of our study was to estimate the seroprevalence of six pathogens transmitted by ticks in HIV-infected persons and blood donors in Poland (B. burgdorferi s.l., A. phagocytophilum, Ehrlichia spp., Babesia spp., Rickettsia spp. Bartonella henselae) to assess the frequency of exposure to such microorganisms in immunocompetent and immunocompromised individuals in endemic regions for I. ricinus ticks. Serum samples were collected from 227 HIV-infected patients and 199 blood donors. All samples were analyzed for antibodies against six tick-borne pathogens and seroprevalence rates were statistically compared between two tested group as well as age, sex and lymphocyte T CD4+ level in HIV infected patients. The seroprevalence of tick-borne infections in HIV-infected patients is higher than that of the healthy population in Poland, although no association between serological status of patients and lymphocyte CD4+ T cell level has been observed. The frequency of tick-borne coinfections and doubtful results of serological tests were significantly higher in HIV-positive individuals. In Poland, the possibility of tick-borne diseases transmission with blood is rather negligible.

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis - United States

Tickborne rickettsial diseases continue to cause severe illness and death in otherwise healthy adults and children, despite the availability of low-cost, effective antibacterial therapy. Recognition early in the clinical course is critical because this is the period when antibacterial therapy is most effective. Early signs and symptoms of these illnesses are nonspecific or mimic other illnesses, which can make diagnosis challenging. Previously undescribed tickborne rickettsial diseases continue to be recognized, and since 2004, three additional agents have been described as causes of human disease in the United States: Rickettsia parkeri, Ehrlichia muris-like agent, and Rickettsia species 364D. This report updates the 2006 CDC recommendations on the diagnosis and management of tickborne rickettsial diseases in the United States and includes information on the practical aspects of epidemiology, clinical assessment, treatment, laboratory diagnosis, and prevention of tickborne rickettsial diseases. The CDC Rickettsial Zoonoses Branch, in consultation with external clinical and academic specialists and public health professionals, developed this report to assist health care providers and public health professionals to 1) recognize key epidemiologic features and clinical manifestations of tickborne rickettsial diseases, 2) recognize that doxycycline is the treatment of choice for suspected tickborne rickettsial diseases in adults and children, 3) understand that early empiric antibacterial therapy can prevent severe disease and death, 4) request the appropriate confirmatory diagnostic tests and understand their usefulness and limitations, and 5) report probable and confirmed cases of tickborne rickettsial diseases to public health authorities.

Severe ehrlichia infection in pediatric oncology and stem cell transplant patients

Ehrlichiosis, a tickborne illness transmitted by tick vectors Amblyomma americanum and Ixodes scapularis, can be acquired in endemic areas. Clinical manifestations range from asymptomatic to fulminant in nature. We report three cases of ehrlichiosis in pediatric oncology patients, one of whom was a stem cell transplant recipient. Early symptoms included fever, malaise, and vague gastrointestinal symptoms. Laboratory abnormalities were initially attributed to chemotherapy toxicity. Illness was severe in all three patients and one patient died even after initiation of doxycycline. These cases emphasize the need for a high index of suspicion for tickborne illness in oncology patients, and the importance of a low threshold for starting empiric treatment before confirming the diagnosis.

[Bacterial, mycobacterial and fungal opportunistic infections in HIV-infected immigrants: diagnosis and treatment]

The number of HIV infected immigrants has increased sharply in Spain. These patients are prone to contracting several different types of opportunistic infections, including bacterial, mycobacterial, fungal and parasitic infections. The present article provides an in-depth review of bacterial and fungal infections, with particular emphasis on those not endemic in our country.

Human ehrlichiosis in transplant recipients

To characterize the impact of immunosuppression on human ehrlichiosis, we reviewed cases of ehrlichiosis occurring in transplant recipients and immunocompetent patients at three hospitals in Nashville, Tennessee. Between 1998 and 2006, 15 transplant patients were identified as having ehrlichiosis, diagnosed either by whole blood polymerase chain reaction (PCR) (n = 14) or serology (n = 1). They were compared with 43 immunocompetent patients diagnosed by whole blood PCR. We retrospectively collected demographic and clinical information. The species of Ehrlichia (E. ewingii or E. chaffeensis) was determined for patients diagnosed by PCR. The 15 transplant recipients with ehrlichiosis included 7 kidney recipients, 6 heart recipients, 1 liver recipient and 1 lung recipient. Transplant recipients had more infections with E. ewingii than immunocompetent patients (23% vs. 5%, p = 0.08). Transplant recipients experienced less rash (0% vs. 36%, p = 0.006) and presented with significantly lower hepatic enzymes, but more leukopenia and renal dysfunction than immunocompetent patients. Doxycycline therapy was started within 48 h of presentation in 73% of transplant recipients and 78% of immunocompetent patients (p = 0.7). No patient died in either group. Ehrlichia infections can occur in transplant recipients who live in an endemic area. With prompt treatment, the infected transplant recipients in our study had similar, favorable outcomes compared to immunocompetent patients.

Ehrlichia infection of the central nervous system

Ehrlichiosis in the United States is caused by three closely related bacterial species (Ehrlichia chaffeensis, Ehrlichia ewingii, and Anaplasma phagocytophilum), all transmitted through tick bite. Although there is variation with respect to geography and tick vector, the clinical manifestations are similar, and treatment of these infections is identical. Ehrlichiosis can present with a spectrum of neurologic manifestations, ranging in severity from headache to meningoencephalitis. Treatment is straightforward if the diagnosis is suspected, but antibiotic therapy should not be delayed pending laboratory confirmation. Doxycycline, the treatment of choice for adults and children with suspected ehrlichiosis, has high bioavailability and can be administered orally in most cases. Therapy is typically continued at least 3 days after the last documented fever. Although there have been no studies specifically evaluating duration or dosing of doxycycline for Ehrlichia meningoencephalitis, anecdotal reports suggest 100 mg doxycycline administered twice daily is effective, despite limited penetration into the cerebrospinal fluid. Because doxycycline interacts with CYP3A4 enzymes, there is potential for drug interactions with a number of medications. In endemic areas, documentation of coinfection with Borrelia burgdorferi, the etiologic agent of Lyme disease, may require prolonging the duration of doxycycline therapy.

The Microbial Rosetta Stone Database: a compilation of global and emerging infectious microorganisms and bioterrorist threat agents

BACKGROUND

Thousands of different microorganisms affect the health, safety, and economic stability of populations. Many different medical and governmental organizations have created lists of the pathogenic microorganisms relevant to their missions; however, the nomenclature for biological agents on these lists and pathogens described in the literature is inexact. This ambiguity can be a significant block to effective communication among the diverse communities that must deal with epidemics or bioterrorist attacks.

RESULTS

We have developed a database known as the Microbial Rosetta Stone. The database relates microorganism names, taxonomic classifications, diseases, specific detection and treatment protocols, and relevant literature. The database structure facilitates linkage to public genomic databases. This paper focuses on the information in the database for pathogens that impact global public health, emerging infectious organisms, and bioterrorist threat agents.

CONCLUSION

The Microbial Rosetta Stone is available at http://www.microbialrosettastone.com/. The database provides public access to up-to-date taxonomic classifications of organisms that cause human diseases, improves the consistency of nomenclature in disease reporting, and provides useful links between different public genomic and public health databases.