Answers
Samar Razaq in Difficult Cases in Primary Care, 2021
Lyme disease is caused by the spirochete bacterium Borrelia burgdorferi. B. burgdorferi is transferred to humans via the hard tick Ixodes dammini, which feeds on animals infected with the bacterium. Introduction of the bacterium into the human bloodstream via tick saliva occurs during a tick bite. Patients may recall this tick bite and the resultant macular lesion that appears at the site of the bite. This lesion then expands over the course of a week and develops into the characteristic rash of Lyme disease: erythema chronicum migrans. While this is occurring the patient may suffer from a prodromal phase in which there is fever and general malaise. The appearance of the typical rash should raise suspicions and trigger appropriate investigations that may include serology (to look for antibodies against the bacterium) and culture from appropriate fluid or tissue. Untreated, there is a significant risk of developing the late manifestations of Lyme disease, which include neurological abnormalities (e.g. meningitis, cranial neuropathy, peripheral neuropathy), heart disease (e.g. myocarditis, pericarditis, atrioventricular block) and rheumatological disease such as arthritis and fatigue. Rarely, the eyes, liver, spleen and testicles may also be involved. Doxycycline is the first-choice antibiotic. Summer forest walkers should be advised to cover up well and remove attached ticks promptly. Q fever is another bacterial zoonosis caused by the bacterium Coxiella burnetii.
Coxiella burnetii
Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward in Case Studies in Infectious Disease, 2010
The patient is infected with Coxiella burnetii and is suffering from chronic Q fever. C. burnetii is an obligate intracellular bacterium with a complex life cycle and related morphological heterogeneity. It is a pleomorphic coccobacillus 0.3–1.0 μm in size (Figure 2). C. burnetii has a cell wall built of approximately 6.5 nm thick outer and inner membranes, which are separated by a peptidoglycan layer (Figure 3). A spore-like stage does not have dipicolinic acid or a spore coat with cysteine characteristic for other gram-positive bacterial spores. Due to these features C. burnetii is considered to be a gram-negative bacterium, although it is almost impossible to stain C. burnetii by the Gram technique. The Gimenez staining method is usually used instead.
Infectious disease
Kaji Sritharan, Jonathan Rohrer, Alexandra C Rankin, Sachi Sivananthan in Essential Notes for Medical and Surgical Finals, 2021
This group includes Rickettsia, Coxiella and Bartonella. Commonly carried by arthropod vectors such as lice, fleas, ticks and mites: Rickettsiae commonly cause typhus, a disease with swinging fever, headache and rash associated with vasculitis and multisystem involvement. Three groups: typhus group (epidemic and endemic typhus), spotted fever group (Rocky Mountain spotted fever, tick typhus, rickettsial pox) and scrub typhus group.Coxiellaburnetii causes an atypical pneumonia (Q fever).Bartonellahenselae causes cat scratch disease; B. quintana causes trench fever.
A contemporary 16-year review of Coxiella burnetii infective endocarditis in a tertiary cardiac center in Queensland, Australia
Published in Infectious Diseases, 2018
Mark R. Armstrong, Kate L. McCarthy, Robert L. Horvath
Q fever is a worldwide zoonotic disease caused by the obligate intracellular bacterium Coxiella burnetii. Q fever was first described in Brisbane, Australia, in 1935 by Derrick with the identification of the pathogen in tissue from infected abattoir workers [1] and its later isolation in 1937 by Burnet [2]. Coxiella burnetii is able to persist in the environment and resides in a wide variety of animal hosts. In Australia C. burnetii is known to be endemic in livestock in Queensland and New South Wales. One study showed that 16.8% of beef cattle in Queensland were sero-positive for Q fever [3]. Queensland has the highest human Q fever notification rate in Australia, followed by New South Wales [4]. From 2003 to 2005, notifications in Queensland and New South Wales for Q fever comprised 86% of all cases in Australia, and accounted for 83% of hospitalizations due to Q fever [5]. In 2015 notification rates in Queensland were 5.3/100,000 and in New South Wales 3.4/100,000, both higher than the national notification rate of 2.5/100,000 [6].
New insights in Coxiella burnetii infection: diagnosis and therapeutic update
Published in Expert Review of Anti-infective Therapy, 2020
Cléa Melenotte, Matthieu Million, Didier Raoult
Q fever is a severe worldwide disease caused by Coxiella burnetii that can lead to major epidemic outbreaks, as reported in the Netherlands with more than 4000 cases in 4 years and nearly 118 deaths, among which 86 were Q fever-related [1,2]. C. burnetii-persistent focalized infection is still challenging physicians, first, because diagnosis of persistent infection can be difficult without symptoms, but mainly because no recent international recommendations have been stated to standardize the therapeutic strategy and improve clinical outcomes. The last two decades have seen new diagnostic tools that have revolutionized clinical practice, polymerase chain reaction, and the 18F-FDG-PET/CT-scan imaging [3–7]. This has allowed us to identify new C. burnetii-infectious foci and not to miss persistent infections, even if serological levels are low (15).
Molecular diagnosis of Coxiella burnetii in culture negative endocarditis and vascular infection in South Korea
Published in Annals of Medicine, 2021
Moonsuk Bae, Hyo Joo Lee, Joung Ha Park, Seongman Bae, Jiwon Jung, Min Jae Kim, Sang-Oh Lee, Sang-Ho Choi, Yang Soo Kim, Yong Shin, Sung-Han Kim
Culture negative endocarditis is a life-threatening condition associated with significant morbidity and mortality. It accounts for 15–40% of all cases of infective endocarditis [1–3]. There are several causes of culture-negative endocarditis. Of these, infection due to intracellular or non-culturable pathogens remains a diagnostic and therapeutic challenge. Coxiella burnetii is the most common causative pathogen [3,4]. Q fever endocarditis is clinically important because the diagnostic delay and the absence of combination treatment can be associated with mortality and serological monitoring is necessary to monitor relapse [5]. In addition, Q fever vascular infection is a disease entity as well-known as Q fever endocarditis, and it is associated with high mortality and major complications [6–9].
Related Knowledge Centers
- Bacteria
- Phagolysosome
- Rickettsia
- Tick
- Virology
- Intracellular Parasite
- Q Fever
- Gram-Negative Bacteria
- Coccobacillus
- Microbiologist