Asploro Journal of Biomedical and Clinical Case Reports
ISSN: 2582-0370
Article Type: Case Report
DOI: 10.36502/2024/ASJBCCR.6356
Asp Biomed Clin Case Rep. 2024 Jun 29;7(2):165-70
Uncut Gemella Haemolysans: A Case of Bacteremia with No Clear Entry Site
Austin Lee1, Akash Pathak1*, Abdirahman Nuh2
1California Northstate University College of Medicine, Elk Grove, CA, USA
2Dignity Health, Carmichael, CA, USA
Corresponding Author: Akash Pathak
Address: 9700 W Taron Dr, Elk Grove, CA 95757, USA.
Received date: 27 May 2024; Accepted date: 22 June 2024; Published date: 29 June 2024
Citation: Lee A, Pathak A, Nuh A. Uncut Gemella Haemolysans: A Case of Bacteremia with No Clear Entry Site. Asp Biomed Clin Case Rep. 2024 Jun 29;7(2):165-70.
Copyright © 2024 Lee A, Pathak A, Nuh A. This is an open-access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.
Keywords: Gemella, Bacteremia, Infective Endocarditis, Gram Positive Cocci
Abstract
Background: Gemella haemolysans is a gram-positive coccus that colonizes the genitourinary system, gastrointestinal system, and upper respiratory tract as an opportunistic pathogen. Berge et al. found that the frequency of Gemella species bacteremia was 4.5 and infective endocarditis was 0.31 per 1,000,000 inhabitants yearly. We report the first case of G. haemolysans bacteremia presenting as new-onset atrial fibrillation with rapid ventricular response (RVR) and acute respiratory failure and present a case series on G. haemolysans bacteremia and infective endocarditis.
Case Presentation: A 58-year-old male with a past medical history including aortic valve bioprosthetic replacement, type 2 diabetes, hypertension, and coronary artery stenting and bypass surgery presented with shortness of breath and confusion. Examination and testing revealed a 40.4°C fever, acute respiratory failure, atrial fibrillation with RVR, congestive heart failure, lactic acidosis, and acute renal failure, with no drug use, dental wounds, or pneumonia. Diltiazem, metoprolol, aspirin, atorvastatin, insulin, heparin, and ceftriaxone were started. TTE and TEE revealed no clear vegetations. Blood cultures revealed Gemella haemolysans. He became stable after 4 days, was electrically cardioverted to sinus rhythm with first-degree AV block, progressed to complete heart block, then had a temporary pacer placed. A repeat TEE demonstrated an aortic root abscess. He underwent redo sternotomy and homograft placement with no complications and was discharged with instructions to complete a six-week course of ceftriaxone.
Discussion: Our patient presented with multiple comorbidities at a younger age compared to the mean (66) and median (70) age of the 4 bacteremia cases in our 8-case series. Preemptive antibiotic treatment may be warranted for prosthetic heart valve patients, with the possibility of urgent valve replacement surgery. Several antibiotics were previously reported in case studies with varying results. The shortest course was 16 days, with most courses lasting 4 to 7 weeks. With no standard treatment, this case series suggests G. haemolysans tends to be susceptible to beta-lactam agents.
Conclusion: Our case highlights the importance of a multidisciplinary approach in the diagnosis and management of Gemella haemolysans bacteremia, particularly in patients with complex medical histories and prosthetic heart valves.
Introduction
Gemella haemolysans, a gram-positive coccus, is typically known to colonize the oropharynx, genitourinary system, gastrointestinal system, and upper respiratory tract as an opportunistic pathogen [1]. It presents as a typical gram-positive bacterium but can become easily decolorized in the Gram staining process and thus appear gram-variable. It is best detected via specialized 16S rRNA gene sequencing, which presents a clinical challenge and can lead to an underreported prevalence [2].
Multiple case reports link the bacterium to invasive infections such as infective endocarditis, meningitis, spondylodiscitis, and eye infections [1]. It commonly presents in patients with poor dental hygiene, heart disease, and immunocompromised conditions [2,3]. Of the Gemella species infective endocarditis cases, G. haemolysans causes around 26% of cases [4]. A retrospective study by Berge et al. found the frequency of Gemella species bacteremia to be 4.5 and infective endocarditis to be 0.31 per 1,000,000 inhabitants yearly [5]. While a handful of bacteremia cases have been reported, to the best of our knowledge, we report the first case of G. haemolysans bacteremia presenting as acute respiratory failure with rapid new-onset atrial fibrillation. Further, unlike most cases of Gemella bacteremia, our patient had no clear entry site for infection, dental disease, immunocompromised status, or drug use.
Case Summary
Our patient is a 58-year-old male with a past medical history of aortic valve stenosis treated with a bioprosthetic valve replacement 4 years ago, poorly controlled type 2 diabetes mellitus, coronary artery bypass surgery, coronary arterial stenting, hypertension, and medication noncompliance who presented to the ED via ambulance with shortness of breath for three days, altered mental status, and fever.
Initial exam and testing revealed a fever of 40.4°C, acute hypoxemic respiratory failure, atrial fibrillation with rapid ventricular response, congestive heart failure, lactic acidosis, and acute renal failure. He was started on diltiazem, metoprolol, aspirin, atorvastatin, insulin, heparin, and ceftriaxone. Transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE) revealed no clear vegetations. Preliminary blood cultures showed Gram positive cocci in clusters. Vancomycin was started. Blood cultures later resulted as Gemella haemolysans, and vancomycin was discontinued while continuing ceftriaxone. The patient had no clear entry site for infection, immunocompromised status or drug use, and denied dental disease. The patient became stable after 4 days and was cardioverted to sinus rhythm with 1st degree AV block. He was transferred to an external hospital with a plan of ceftriaxone 2g daily for six weeks.
Duke criteria classification for infective endocarditis showed positivity for the three minor criteria of fever, positive blood culture that does not meet major criteria, and a predisposing heart condition. Since three minor criteria were met, a possible case of infective endocarditis was noted. One possible major criteria, blood culture positivity, was not definitive as G. haemolysins represents an atypical microorganism for infective endocarditis.
After being transferred, the patient developed progressive to complete heart block. A repeat TEE performed 7 days after the initial TEE demonstrated an aortic root abscess, and coronary angiogram demonstrated no significant coronary artery disease. For his complete heart block, the patient had a temporary pacer placed. The patient was transferred back to the original hospital for redo sternotomy and homograft placement. Surgery was performed with no intraoperative or postoperative complications, and the patient was discharged with instructions to complete the six week course of ceftriaxone 2g daily.
Discussion
Gemella haemolysans represents an extremely rare and difficult to identify cause of bacteremia with only a handful of cases reported in the literature. Several of them are highlighted in Table-1 while the majority of G. haemolysins cases reported are of infective endocarditis [6-9]. In these patients, utilizing the Duke criteria is critical as there is a high risk of infective endocarditis and complications from IE. Of note, bacteremia cases of embolic stroke secondary to infective endocarditis, liver abscess, occult bacteremia, duodenal ulcer perforation secondary to peritonitis, and automated implantable cardioverter defibrillator (AICD) lead infection have been described [1,10-13]. To the best of our knowledge this is the first G. haemolysans bacteremia presentation of acute respiratory failure with rapid new onset atrial fibrillation.
Table-1: Case Report Series on Gemella Haemolysans Bacteremia and Selective Cases of Gemella Haemolysans Infective Endocarditis
Our patient, a 58-year-old male, presents with multiple pre-existing conditions at a younger age compared to most other cases of bacteremia (Table-1). The mean and median age of bacteremia cases reported in Table-1 is 66 and 70, respectively. The Gemella species represents an emerging pathogen for bacteremia among the elderly and should be given consideration by clinicians. This case stands out as one of the few reported cases of Gemella species bacteremia that did not present in an elderly patient, representing a possibly growing younger population susceptible to this rare microorganism.
Gemella species is commonly associated with infective endocarditis and our patient’s initial transesophageal echocardiogram showed thickening of the aortic valve with no vegetations. This was surprising given the patient’s history of valve replacement and preliminary positive blood cultures. Despite initially medically stabilizing and cardioversion, the patient redeveloped fever and eventually developed complete heart block. The subsequent TEE revealed an aortic root abscess, despite prophylactic treatment for infective endocarditis when there was no evidence of abscess.
Risk factors of Gemella species infection include dental disease, colorectal disease, or immunocompromised status. The three most common causes of Gemella species infective endocarditis are dental (73%), intravenous drug abuse (13%), and colonic disease (13%) while the source of bacteremia is not commonly identified [1,4,10-13]. Our patient did not present with a clear source of infection and had no pre-existing or known dental disease. However, he was noted to periodically have dental problems and stated he fails to appropriately take care of his teeth.
Almost 94% of Gemella infective endocarditis cases have heart valve involvement and about 24% of patients affected on the aortic valve [4]. Our patient had a history of aortic valve stenosis treated with a bioprosthetic valve replacement in 2019 and coronary artery disease treated with a coronary artery bypass graft and coronary arterial stenting. His initial TEE showed thickening on the aortic valve but no formation of vegetations. With Raja et al. also describing a case of G. haemloysans endocarditis in a patient with prosthetic mitral and aortic valves, pre-emptively treating for infective endocarditis in G. haemolysans infected patients with prosthetic heart valves may be warranted [14]. Treating prophylactically for prosthetic heart valve patients may be an appropriate recommendation for cases of Gemella bacteremia. Past literature suggests Gemella haemolysans is susceptible to β-lactams, vancomycin, clindamycin, and meropenem [1,2,4,6-10].
However, as seen in this case, a high index of suspicion for infective endocarditis and prosthetic valve involvement should be maintained despite a patient’s initial testing and imaging. Even with an initial response to antibiotics and symptomatic improvement, a patient with Gemella Haemolysans bacteremia may be susceptible to quick clinical deterioration, especially with a history of a prosthetic valve. Therefore, surgeons should be prepared to operate and replace the valve as if treating any other Gram-positive cocci.
When antibiotic therapy fails to alleviate symptoms and produce negative blood cultures in IE patients, surgical therapy is required to remove infected and necrotic tissue with subsequent repair or replacement of the damaged valve [15]. As outlined by the 2016 American Association for Thoracic Surgery Consensus Guidelines: Surgical Treatment of Infective Endocarditis, the aortic root abscess seen on the followup TEE in our patient and the patient’s bioprosthetic aortic valve indicates a Class IIa indication for surgery [16]. Musci et al. found that homograft aortic root replacement with periannular abscess formation showed better survival with both early and long-term results in native valve endocarditis compared to prosthetic valve endocarditis [17].
Based on this case, following traditional management and protocols to treat bacteremia and suspected infective endocarditis while awaiting for cultures and sensitivities to return appears to be appropriate in the management of Gemella bacteremia. Especially in cases with a high risk of infective endocarditis based on patient factors, clinicians should have a low threshold to obtain repeat imaging to assess prosthetic valve involvement in the setting of Gemella bacteremia. Transferring the patient to a different facility only to return for operative management should be avoided when there is a high risk of valvular involvement requiring surgery. More research must be conducted on Gemella species bacteremia regarding antibiotic sensitivity in the community to determine appropriate and effective coverage to help prevent progression to infective endocarditis.
Conclusion
Gemella haemolysans bacteremia presents a complex diagnostic challenge. Obtaining early blood cultures and treating patients with a bioprosthetic valve prophylactically with ceftriaxone or other historically effective antibiotics may represent an avenue for treatment. A high index of suspicion should be maintained for prosthetic valve involvement despite initial testing and imaging, and treatment teams should be prepared for cardiac interventions and valve replacement. Our case underscores the importance of a multidisciplinary approach involving infectious disease specialists, cardiologists, and surgeons in the diagnosis and management of Gemella haemolysans bacteremia, particularly in patients with complex medical histories and prosthetic heart valves. Further research is warranted to better understand the optimal management strategies for this rare but potentially life-threatening infection.
Ethics Statement
Human subjects: Consent was obtained or waived by all participants in this study. Written informed consent has been obtained from the patient and family to publish this paper. This case report is IRB-exempt, and all patient information is de-identified.
Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following:
Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work.
Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work.
Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.
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