From the Guidelines
Gemella haemolysans is a type of bacteria that is a gram-positive, facultatively anaerobic coccus, which can occasionally act as an opportunistic pathogen, particularly in immunocompromised individuals, and is typically treated with penicillin or alternative antibiotics such as vancomycin or ceftriaxone.
Overview of Gemella haemolysans
Gemella haemolysans is a species of bacteria that shares some physiological characteristics with nutritionally variant streptococci, and endocarditis caused by these organisms should be treated with more aggressive combination therapy, as recommended for nutritionally variant streptococcal endocarditis 1.
Infections and Treatment
Infections caused by G. haemolysans include endocarditis, meningitis, bacteremia, and various localized infections.
- The first-line antibiotic choice for treating G. haemolysans infections is penicillin, with typical adult dosing of penicillin G 12-24 million units daily divided every 4-6 hours for severe infections, administered for 2-6 weeks depending on the infection site.
- For penicillin-allergic patients, vancomycin (15-20 mg/kg IV every 8-12 hours) or ceftriaxone (1-2g daily) are appropriate alternatives.
- The organism is usually susceptible to most beta-lactam antibiotics, but resistance patterns can vary, so antimicrobial susceptibility testing is recommended to guide definitive therapy 1.
Importance of Early Identification and Treatment
Early identification and treatment are important as G. haemolysans infections, particularly endocarditis, can lead to significant complications if not properly managed.
- Endocarditis caused by G. haemolysans has been more difficult to cure microbiologically than has endocarditis caused by a strain of non-nutritionally variant group viridans streptococci.
- Patients with endocarditis caused by G. haemolysans should be treated with a regimen that is recommended for enterococcal endocarditis.
From the Research
Characteristics of Gemella haemolysans
- Gemella haemolysans is a commensal bacterium of the upper respiratory tract 2
- It is a catalase-negative, facultative anaerobic, Gram-positive coccus 3
- Gemella haemolysans is often incorrectly identified on routine Gram stain and culture, requiring advanced techniques such as PCR 3
Infections Caused by Gemella haemolysans
- Gemella haemolysans can cause rare infections such as acute endocarditis, meningitis, and spondylodiscitis 2
- It has been reported to cause infective endocarditis, septicaemia, and post-neurosurgical meningitis 2
- A rare case of Gemella haemolysans automated implantable cardioverter defibrillator (AICD) lead infection has been reported 3
Treatment of Gemella haemolysans Infections
- The sensitivity profile of Gemella haemolysans generally shows sensitivity to penicillins, cyclines, and glycopeptides, and resistance to trimethoprime-sulfamethoxazole 2
- Standard treatment for Gemella haemolysans infections consists of β-lactam inhibitors and aminoglycosides 3
- Alternative antibiotic treatments, such as vancomycin and ceftriaxone, have been used successfully in some cases 3, 4
- Synergism between penicillin G and streptomycin or gentamicin, and between vancomycin and streptomycin or gentamicin, has been demonstrated 4
Diagnosis and Prevalence
- The difficulties in etiological diagnosis of Gemella haemolysans infections, related to the problems in identifying this germ, suggest that the prevalence of Gemella haemolysans infections is greatly underrated 2
- A comprehensive geriatric assessment can be beneficial in the treatment of elderly patients with Gemella haemolysans endocarditis 5