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[Tricuspid endocarditis caused by penicillin-resistant Staphylococcus aureus: 2 cases in parenteral drug addicts]
F Dronda1, F Chaves, L López-Cubero
1Unidad de Enfermedades Infecciosas-Microbiología, Hospital General Penitenciario, Madrid.
Background:
Staphylococcus aureus is the main causal agent of infectious endocarditis (IE) in intravenous drug addicts (IVDA) with most of the strains, isolated in Spain being resistant to penicillin and sensitive to methycillin, although the latter condition varied in recent years. Two cases of IE caused by S. aureus strains sensitive to penicillin in IVDA are presented.
Methods:
All bacteremia episodes diagnosed in the Hospital General Penitenciario (Madrid) over a 33-month period (March 1991 to December 1993) were prospectively studied. Special attention was given to patients diagnosed of IE. Blood cultures were processed according to the usual technique by a non radiometric system.
Results:
One hundred and four bacteremias were detected with 14 being produced by S. aureus. Ten episodes of the total number of bacteremias fulfilled criteria for IE with 2 being produced by strains of S. aureus sensitive to penicillin (CMI < 0.06 mu/ml). Both patients had coinfection by HIV. The clinical evolution prior to diagnosis was prolonged although clinical and microbiologic cure were achieved with intravenous beta-lactam antibiotics treatment, without complications.
Conclusions:
Despite the low incidence of the isolation of Staphylococcus aureus sensitive to penicillin (< 3%) recently observed in Spain, strains producing severe infections, showing patterns of sensitivity such as those found during the preantibiotic era, may still be isolated.
Insights
Two cases of infectious endocarditis (IE) in intravenous drug addicts (IVDA) were caused by penicillin-sensitive Staphylococcus aureus. Despite low incidence, these strains can cause severe infections and are treatable with beta-lactam antibiotics.
Area of Science:
- Infectious Diseases
- Microbiology
- Clinical Medicine
Background:
- Staphylococcus aureus is a primary cause of infectious endocarditis (IE) in intravenous drug addicts (IVDA).
- Penicillin resistance in S. aureus strains is common in Spain, though methicillin sensitivity has varied.
- This study presents two rare cases of IE caused by penicillin-sensitive S. aureus in IVDA.
Observation:
- A 33-month prospective study of bacteremia episodes was conducted at Hospital General Penitenciario (Madrid).
- 104 bacteremias were identified, with 14 caused by S. aureus.
- Two cases of IE were caused by S. aureus strains sensitive to penicillin (CMI < 0.06 mu/ml).
Findings:
- Both patients with penicillin-sensitive S. aureus IE were coinfected with HIV.
- Prolonged clinical evolution was observed before diagnosis.
- Complete clinical and microbiological cure was achieved with intravenous beta-lactam antibiotics without complications.
Implications:
- Penicillin-sensitive Staphylococcus aureus strains, though rare (<3% in Spain), can still cause severe infections in IVDA.
- These strains exhibit sensitivity patterns reminiscent of the pre-antibiotic era.
- Effective treatment with beta-lactam antibiotics is possible for these infections.