Agents of cardiovascular infections

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.

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

 * 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
Therapy according to etiology.
 * CG, CT, etiological agents are identified by examination of punctured fluid.

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.

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,...

Related articles

 * Infectious endocarditis
 * Myocarditis
 * Pericarditis