Mycoplasma hominis, a Rare but True Cause of Infective Endocarditis

Abstract

e Mycoplasma spp. are rarely recognized agents of infective endocarditis. We report a case of Mycoplasma hominis prosthetic valve endocarditis diagnosed by 16S ribosomal DNA (rDNA) PCR and culture of valves in a 74-year-old man. We reviewed the literature and found only 8 other cases reported. CASE REPORTA 74-year-old man, with a history of hypertension and mitral and aortic biological prosthetic valve replacement since June 2013 and stroke in August 2013, was admitted in December 2013 to the intensive care unit of the University Hospital of Saint Etienne, Saint-Etienne, France, for dizziness and cardiac and kidney failure. Physical examination revealed a low-grade fever (38.2°C) and an aortic murmur. A first transthoracic echocardiography procedure showed a decrease in the left ventricular ejection function fraction (LVEF) to 35% compared to anterior data (LVEF, 45% to 50% in June 2013), whereas the prosthetic valves appeared functional. The results of a second transthoracic echocardiography procedure, performed only 2 days later, were consistent with aortic prosthetic endocarditis associated with grade IV aortic insufficiency, a decrease in the LVEF to 25%, and an abscess of mitroaortic intervalvular fibrosa. Four days later, 2 of 6 blood cultures grew with the same strain of Staphylococcus epidermidis after 19 and 23 h, respectively (blood culture system, Bactec FX40; Becton Dickinson). Both positive blood cultures were obtained through an arterial catheter. The results of peripheral blood cultures obtained through vein and central venous catheters remained negative. Diagnosis of infective endocarditis (IE) was based on Duke's criteria (1 major criterion [valvular abscess] and 3 minor criteria [fever over 38°C, blood culture positive for S. epidermidis, and predisposing heart condition, i.e., history of valvular replacement]). The initial antibiotic regimen included vancomycin (20 mg/kg of body weight/day) and linezolid (600 mg twice a day).Cardiac surgery was performed 24 h after the diagnosis of infective endocarditis. Cardiac surgeons observed destruction of the mitroaortic intervalvular fibrosa, with dehiscence of the aortic prosthesis, and multiple abscesses. Aortic valve replacement with a biologic prosthesis associated with a reconstruction of the mitroaortic fibrosa was performed. After surgery, linezolid was replaced by daptomycin (8 mg/kg every 48 h) due to acute kidney injury. Serological testing for Bartonella spp. and Coxiella burnetii was negative. Broad-range 16S ribosomal DNA (rDNA) PCR was performed on the cardiac valve, using the primers described by Harris and Hartley (1), followed by sequencing; the results were positive for Mycoplasma hominis. Initially, routine cultures of the cardiac valve performed on standard media, including blood agar and chocolate agar for 48 h and Schaedler broth for 15 days, remained sterile. After the results of the PCR were seen, a culture of the valve was plated on chocolate agar for longer and led to the growth of translucent and tiny colonies after 5 days. A...

Infective Endocarditis Secondary to Mycoplasma pneumoniae

“…However, a case reported from Argentina by Scapini et al showed vegetations in TTE, and the patient was started on clarithromycin after cultures grew MP [ 14 ]. In comparison, our patient also had vegetations in his TTE and showed dynamic clinical improvement after initiation of doxycycline, similar to a previously reported case [ 15 ].…”

Blood Culture-Negative Infective Endocarditis by Mycoplasma hominis: Case Report and Literature Review

“…The narrative review yielded 11 cases of IE by M. hominis. The data summarized in Table 2 show that 72.7% of the patients were male with a mean age of 45 years (range, 4-74 years) and out of the 11 patients, 10 had a history of heart surgery for valve replacement, valve repair, or congenital malformation [13][14][15][16][17][18][19][20][21][22][23], as in the present case. The underlying pathogenic mechanism of endocarditis by M. hominis appears to be nosocomial, possibly secondary to bacteremia caused by the instrumentalization of colonized areas before, during, or after surgery.…”

“…The most frequent clinical signs/symptoms in the published cases were fever and valve insufficiency [13][14][15][16][17][18][19][20][21][22][23]. Serial blood cultures were negative in all 11 patients.…”

“…Serial blood cultures were negative in all 11 patients. M. hominis was identified by culture in six cases (in combination with molecular analysis in three of these) and by molecular analysis (16 s ribosomal DNA PCR) of the explanted valve in the remaining five [13][14][15][16][17][18][19][20][21][22][23].…”

Clinical implications of the genus Mycoplasma

“…Fue el primer micoplasma de origen humano en ser aislado [ 4 ]. Sus implicaciones clínicas son muy variadas: infección periprotésica [ 82 , 83 ], artritis séptica [ 84 , 85 ]; ventriculitis asociada a drenaje extraventricular [ 86 ], infecciones genitales femeninas [ 87 , 88 ], neumonía [ 89 ], meningitis postoperatoria [ 90 ], meningitis neonatal [ 91 ], infección postrasplante [ 92 - 94 ], absceso intramedular [ 95 ], absceso pélvico [ 96 ], endocarditis [ 97 ], mediastinitis, pleuritis y pericarditis postoperatoria [ 98 ]; embarazo patológico [ 99 ], vaginosis bacteriana [ 100 ] y pielonefritis [ 101 ]. En cuanto a su patogenicidad, M. hominis posee P50 y P100, que favorecen su adherencia a células eucariotas [ 102 ].…”