Agents of cardiovascular infections

Infectious edocarditis. Cause: Haemophilus parainfluenzae.

Heart infections include infectious endocarditis, myocarditis and pericarditis; vascular infections include focal infections of large blood vessels, infections affecting the endothelium of small vessels and catheter infections.

Heart infections

Infectious endocarditis

• Serious disease, infected thrombus is attached to the heart valve or wall endocardium, there is a risk of embolization.
• Nozocomial infections – in developed countries 5–29% of cases (risk of invasive procedures).
• Intact endothelium is resistant to all pathogens except S. aureus.

Ethiological agents

Staphylococcus aureus

• Affects altered and healthy valves both, also valve replacements;
• the risk of embolization into distant organs;
• isolated in 20% of cases.

Coagulase-negative staphylococci (Staphylococcus epidermidis, St. haemolyticus, St. hominis)

• Commensal skins, high affinity for artificial surfaces;
• the most common cause of endocarditis on an artificial valve, pacemaker, the cause of catheter sepsis;
• most times without embolization;
• less sensitive to ATB.

Streptococci

• Viridans i hemolytic streptococci;
• S. pneumoniae – etiological agent in 60% of cases;
• Capture in anaerobic blood culture vessels, cultivation on enriched medium;
• They damage already pre-affected valves;
• S.mitis, S.sanguis, S.mutans, S.bovis.

Enterococci

• They enter the bloodstream after urinary tract or bile duct infections;
• Complication is resistance to ATB.

Gram-negative bacteria

• E.coli, salmonella, Klebsiella.

Pseudomonads

• Nosocomial endocarditis, common in polymorbid patients;;
• high lethality (up to 80%);
• treated with an emergency surgery.

Candida, Aspergillus

• Infectious agents in immunodeficient and immunosuppressed individuals;
• large vegetation (up to several cm) → risk of valve obturation, massive emboli;
• complicated identification from blood culture.

Diagnostics

• Echocardiography, blood cultivation (taking at least two samples).

Therapy

• ATB according to infectious agent, usually given in high doses;
• hospitalization required, in some cases surgery.

Myocarditis

Viral myocarditis.

• Inflammatory myocardial infarction.

Etilogy

• Most often of viral origin;
• Coxsackie B viruses, adenoviruses, enteroviruses, Borrelia burgdorferi, leptospiry, treponemy, diphtheria toxin;
• fungal myocarditis;
• parasitic myocarditis - rare in the Czech Republic, higher incidence in tropical areas, in recent years complications of toxoplasmosis in AIDS patients.

Diagnostics

• Echocardiography, CRP, histological analysis of punctured tissue;
• So far there is no reliable test for diagnosis in vitram.

Therapy

• Anti-infective preparations according to the infectious agent.

Pericarditis

• Serous Pericarditis – of viral origin, spirochetes;
• purulent pericarditis - complications of bacterial sepsis, S.aureus, gram-positive bacteria;
• giant cell pericarditis of tuberculosis origin.

Diagnostics

• CG, CT, etiological agents are identified by examination of punctured fluid.

Therapy according to etiology.

Clinical specimens for heart infections

• Blood culture: blood culture vessels with broth, if there are signs of growth, the sample is further examined microscopically and by culture;
• cultivation: blood agar with staphylococcal line, cultivation in atmosphere with 5% CO 2 , End's soil or MacConkey agar, anaerobic cultivation, Sabouraud's agar;
• if slow-growing bacteria are suspected, the seemingly negative blood culture must be examined microscopically, inoculated on chocolate agar, after three weeks , incubated in an atmosphere with 5% CO₂ for three to four weeks.

Vascular infections

Focal vascular infections

• Infectious aneurysm - streptococci, S. aureus;
• endarteritis – S. aureus;
• thrombus infections in the aortic aneurysm - salmonella;
• purulent thrombophlebitis - streptococci, anaerobic bacteria.

Nosocomial catheter infections

• Central venous catheter infections in particular, peripheral venous catheter infections more frequent but less severe;
• S. epidermidis, coagulase-negative staphylococci, S. aureus, E. faecalis, E. coli, Candida albicans,...

Links

Related articles

• Infectious endocarditis
• Myocarditis
• Pericarditis

Used literature

• BENEŠ, Jiří, et al. Infekční lékařství. 1. edition. Galén, 2009. vol. 651. ISBN 978-80-7262-644-1.

• POVÝŠIL, Ctibor – ŠTEINER, Ivo – DUŠEK, Pavel, et al. Speciální patologie. 2. edition. Praha : Galén, 2007. vol. 430. ISBN 978-807262-494-2.