Bacillus cereus prosthetic valve endocarditis

A case of prosthetic valve endocarditis and aortic abscess due to Bacillus cereus

Bacillus cereus (B. cereus) is commonly found in the environment and is often considered a blood culture contaminant. However, in patients with specific risk factors such as intravenous drug use, central venous access catheters, immunosuppression, or prosthetic valves, B. cereus can cause severe infections. Herein, we present a case of prosthetic valve endocarditis (PVE) caused by B. cereus in an 84-year-old woman with a history of aortic valve replacement for aortic stenosis five years earlier. She presented with anorexia, and her physical examination revealed tenderness in the left upper quadrant of the abdomen. Blood culture grew B. cereus, and a CT scan showed splenic infarction, raising suspicion of PVE. Transesophageal echocardiogram (TEE) revealed an abscess around the left coronary cusp of the aortic valve and a 15 mm vegetation. Due to the patient's high risk for post-operative complications and her unwillingness to undergo surgery, the surgery was deferred. Instead, she was successfully treated with six weeks of intravenous vancomycin and discharged home. Follow-up TEE demonstrated resolution of the vegetation and valvular abscess. At her six-month post-discharge evaluation, no signs of active infection were noted including fever or worsening heart failure. Although surgery is typically recommended for most cases of PVE, conservative treatment can be considered as an alternative option for selected patients.

A Case of Persistent Bacillus cereus Bacteremia Responding to a Combination of Vancomycin and Gentamicin

A 56-year-old woman with a history of connective tissue disease developed fever, and Bacillus cereus (B. cereus) was detected in blood cultures. Therefore, treatment with vancomycin (VCM) was initiated. Since her blood cultures persistently detected B. cereus despite peripheral intravenous catheter replacement and VCM treatment, concomitant treatment with gentamicin (GM) was started. Blood cultures then became negative. Persistent B. cereus bacteremia responded to combination therapy with VCM and GM. This combination therapy may increase the risk of developing renal dysfunction, but the risk can be mitigated by appropriate therapeutic drug monitoring (TDM) and dose adjustments to achieve successful treatment.

A Rare Case of Native Mitral Valve Bacillus Cereus Endocarditis Culminating Into a Cerebrovascular Infarction

We report a case of a 56-year-old man who presented initially with a sudden onset of right-sided facial droop and weakness, aphasia, and confusion with no associated fever, chills, syncope, fatigue, weight loss, night sweats, nausea, vomiting, diarrhea, odontalgia, palpitations, cough, or dyspnea. Code stroke was called and the patient received tissue plasminogen activator (tPA) with subsequent resolution of his symptoms. Cranial magnetic resonance imaging showed left frontal punctate cortical restricted diffusion consistent with subacute to acute infarction. Transesophageal echocardiogram showed a severely thickened anterior mitral valve leaflet with a shaggy echodensity consistent with a vegetation. Blood cultures grew Bacillus cereus sensitive to clindamycin, trimethoprim sulfamethoxazole, and vancomycin. He was initially treated with ampicillin, clindamycin, and vancomycin and was eventually maintained solely on vancomycin. He had complete return of his neurological function and was discharged on intravenous antibiotic to complete a 6-week course.

A Case Series and Review of Bacillus Cereus Endocarditis from India

Introduction:

Bacillus cereus is a gram positive bacilli found commonly in the soil and environment. It is a bacteria rarely associated with endocarditis.

Case History:

Intravenous drug abuse, presence of valvular defects, pacemakers, immunodeficiency are some of the known risk factors for B.cereus endocarditis. We present here a case series of two patients with B.cereus endocarditis along with a review of the literature.

Conclusion:

This is the first report of B.cereus endocarditis from India to the best of our knowledge.

Central Venous Access Device-Related Bacillus Cereus Endocarditis: A Case Report and Review of the Literature

Bacillus cereus typically presents as a gastrointestinal infection, but rarely manifests as systemic disease. This report describes a case of B. cereus-related endocarditis that presented as a sickle cell crisis and bacteremia. Initial clinical suspicion was for laboratory contamination of blood cultures. The case herein described is intended to demonstrate an uncommon presentation of B. cereus infection and highlights the value of an aggressive need to further investigate and interpret unexpected blood culture findings in clinical practice, early adequate antimicrobial therapy, prompt diagnosis, and consideration to urgent surgical interventions in such cases.

Quorum sensing in Bacillus thuringiensis is required for completion of a full infectious cycle in the insect

Bacterial cell-cell communication or quorum sensing (QS) is a biological process commonly described as allowing bacteria belonging to a same pherotype to coordinate gene expression to cell density. In Gram-positive bacteria, cell-cell communication mainly relies on cytoplasmic sensors regulated by secreted and re-imported signaling peptides. The Bacillus quorum sensors Rap, NprR, and PlcR were previously identified as the first members of a new protein family called RNPP. Except for the Rap proteins, these RNPP regulators are transcription factors that directly regulate gene expression. QS regulates important biological functions in bacteria of the Bacillus cereus group. PlcR was first characterized as the main regulator of virulence in B. thuringiensis and B. cereus. More recently, the PlcR-like regulator PlcRa was characterized for its role in cysteine metabolism and in resistance to oxidative stress. The NprR regulator controls the necrotrophic properties allowing the bacteria to survive in the infected host. The Rap proteins negatively affect sporulation via their interaction with a phosphorelay protein involved in the activation of Spo0A, the master regulator of this differentiation pathway. In this review we aim at providing a complete picture of the QS systems that are sequentially activated during the lifecycle of B. cereus and B. thuringiensis in an insect model of infection.

Pacemaker-associated Bacillus cereus endocarditis

We report the case of a pacemaker-associated Bacillus cereus endocarditis in a nonimmunocompromised patient. Antibiotic treatment was ineffective, and the pacemaker had to be removed. B. cereus was cultured from several blood samples and from the pacemaker electrodes. This case underlines the contribution of the rpoB gene for Bacillus species determination.

Bacillus cereus endocarditis in native aortic valve

Bacillus cereus endocarditis is rare. It has been implicated in immunocompromised individuals, especially in intravenous drug users as well as in those with a cardiac prosthesis. The patient was a 31-year-old ex-intravenous drug addict with a past history of staphylococcal pulmonary valve endocarditis, who presented with symptoms of decompensated cardiac failure. Echocardiography showed severe aortic regurgitation with an oscillating vegetation seen on the right coronary cusp of the aortic valve. The blood cultures grew Bacillus cereus. We report this as a rare case of Bacillus cereus endocarditis affecting a native aortic valve.

Native valve Bacillus cereus endocarditis in a non-intravenous-drug-abusing patient

Bacillus cereus is a rare cause of endocarditis, typically associated with intravenous drug abuse, rheumatic heart disease, prosthetic heart valves, pacemakers, or immunodeficiency. We present the first case of native valve Bacillus cereus endocarditis with no apparent risk factors. The patient had a fulminant course requiring emergent valve replacement.

Early murine immune responses from endotracheal exposures to biotechnology-related Bacillus strains

An immunology-based in vivo screening regime was used to assess the potential pathogenicity of biotechnology-related microbes. Strains of Bacillus cereus (Bc), Bacillus subtilis (Bs), Bacillus thuringiensis (Bt), and Bt commercial products (CPs) were tested. Balb/c mice were endotracheally instilled with purified spores, diluted CP, or vegetative cells (VC) (live or dead). Exposed mice were evaluated for changes in behavioral and physical symptoms, bacterial clearance, pulmonary granulocytes, and pulmonary and circulatory pyrogenic cytokines (interleukins (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α), as well as acute phase biomarkers (fibrinogen and serum amyloid A). Except for some differences in clearance rates, no marked effects were observed in mice exposed to any spore at 10(6) or 10(7) colony forming units (cfu). In contrast, live Bc or Bt VCs (10(5) or 10(6) cfu) produced shock-like symptoms (lethargy, hunched appearance, ruffled fur, and respiratory distress), and 11-200-fold elevations in pyrogenic cytokines at 2-h post-exposure. In the study, 4-h effects included increased lethargy, ocular discharge, and 1.5-4-fold rise in circulatory acute phase markers, but no indications of recovery. Bs VC did not produce any changes in symptoms or biomarkers. After 2 or 4 h of exposure to dead VC, increases of only plasma IL-1? and TNF-α (4.6- and 12.4-fold, respectively) were observed. These findings demonstrate that purified spores produced no marked effects in mice compared to that of metabolically active bacteria. This early screening regime was successful in distinguishing the pathogenicity of the different Bacillus species, and might be useful for assessing the relative hazard potential of other biotechnology-related candidate strains.

Bacillus cereus, a volatile human pathogen

Bacillus cereus is a Gram-positive aerobic or facultatively anaerobic, motile, spore-forming, rod-shaped bacterium that is widely distributed environmentally. While B. cereus is associated mainly with food poisoning, it is being increasingly reported to be a cause of serious and potentially fatal non-gastrointestinal-tract infections. The pathogenicity of B. cereus, whether intestinal or nonintestinal, is intimately associated with the production of tissue-destructive exoenzymes. Among these secreted toxins are four hemolysins, three distinct phospholipases, an emesis-inducing toxin, and proteases. The major hurdle in evaluating B. cereus when isolated from a clinical specimen is overcoming its stigma as an insignificant contaminant. Outside its notoriety in association with food poisoning and severe eye infections, this bacterium has been incriminated in a multitude of other clinical conditions such as anthrax-like progressive pneumonia, fulminant sepsis, and devastating central nervous system infections, particularly in immunosuppressed individuals, intravenous drug abusers, and neonates. Its role in nosocomial acquired bacteremia and wound infections in postsurgical patients has also been well defined, especially when intravascular devices such as catheters are inserted. Primary cutaneous infections mimicking clostridial gas gangrene induced subsequent to trauma have also been well documented. B. cereus produces a potent beta-lactamase conferring marked resistance to beta-lactam antibiotics. Antimicrobials noted to be effective in the empirical management of a B. cereus infection while awaiting antimicrobial susceptibility results for the isolate include ciprofloxacin and vancomycin.

Successful surgical drainage and aggressive medical therapy in a preterm neonate with Bacillus cereus meningitis

Bacillus cereus meningitis is a rare disease with a very high mortality rate in neonates. The authors present the rare case of a premature infant with B. cereus bacteremia and subsequent intracranial abscesses. In addition to aggressive medical therapy, surgical drainage was performed via a left frontal mini-craniotomy. At 15 months of age, the patient had mild developmental delay, cortical blindness, and sensorineural hearing loss. The clinical case is described and difficulties in the management of B. cereus meningoencephalitis in infants are discussed.

Management of Bacillus bacteremia: the need for catheter removal

Bacillus species are biofilm-forming organisms that are associated with Bacillus catheter-related bloodstream infections (CRBSIs). The optimal treatment of Bacillus CRBSIs is not known. Therefore, in the current study, we determined the role of long-term central venous catheter (CVC) removal and treatment with vancomycin compared with other agents in Bacillus CRBSIs by retrospectively reviewing the medical records of cancer patients with Bacillus bacteremia who had been treated at our institution from December 1990 to March 2008. True bacteremia was defined as a positive blood culture (>15 colony-forming units/mL) with signs and symptoms of infection (such as fever and chills). Bacillus CRBSI was defined in accordance with the Infectious Diseases Society of America guidelines as probable or definite. There were 94 Bacillus bacteremia episodes, 93 of which (99%) were Bacillus CRBSIs (28% definite and 71% probable). Neutropenia during bacteremia occurred in 29%. Almost all bacteremia patients (99%) had been treated with antibiotics; 63% had received vancomycin. Sepsis with hypotension occurred in 6%, and endocarditis in 1%. Bacillus isolates were susceptible to linezolid (100%), vancomycin (98%), tetracycline (77%), and rifampin (67%). All 4 recurrences occurred in patients in whom the CVC had not been removed (12%), whereas no recurrences occurred in patients whose CVC had been removed (p = 0.028). Patient outcome, in terms of fever and hospitalization duration after the infection, was similar in patients who had received < or =10 days of systemic antibiotics compared with patients who had received >10 days. In conclusion, catheter retention in patients with Bacillus CRBSIs is associated with a significantly higher recurrence rate. If the CVC is retained, treatment with non-vancomycin antibiotics is associated with significantly shorter hospitalization duration after the infection, which may be because glycopeptide antibiotics have poor activity against bacilli embedded in biofilm.

Bacillus Cereus Endocarditis in a permanent pacemaker: a case report

Introduction

Bacillus Cereus endocarditis is a rare condition which has been implicated in intravenous drug users, and in patients with prosthetic heart valves. We report a rare case of Bacillus Cereus infecting a permanent pacing wire.

Case presentation

A 69 year old female with a permanent pacemaker presented with rigors, sweats and weight loss. Blood cultures grew Bacillus Cereus; Transesophageal echocardiogram demonstrated a mobile lesion attached to the pacing wire. She was treated with appropriate intravenous antibiotics for 6 weeks with a good clinical recovery at 6 months follow up.

Conclusion

This case reminds the clinician to have a high index of suspicion for endocarditis in any patient with cardiac prosthesis and to pursue the blood culture results even for rare and unexpected organisms. It also suggests the possibility of a trial of antibiotic therapy prior to prosthesis removal in select patients who are not in heart failure and hemodynamically stable.