Bacillus cereus panophthalmitis associated with intraocular gas bubble

Infective endocarditis due to Bacillus cereus in a pregnant female: A case report and literature review

Incidence of infective endocarditis during pregnancy is around 0.006% with high maternal and fetal mortality. Bacillus cereus is an extremely rare cause for endocarditis in intravenous drug abusers (IVDA) or those with valvular disease or devices such as pacemakers. We report a case of B. cereus endocarditis, which, to the best of our knowledge, has never been reported in pregnancy. A 30-year-old, 25-week pregnant female presented with right shoulder pain, swelling and erythema on the lateral aspect of deltoid muscle from large abscess over her deltoid muscle. She was found to have a vegetation on the native tricuspid valve. Cultures from abscess fluid and blood cultures grew B. cereus, she was appropriately treated with antimicrobials and had favorable outcomes. There are <20 cases of B. cereus endocarditis reported but none during pregnancy. When cultures grow unusual organisms the case must be thoroughly investigated. This case illustrates a rare situation (endocarditis in pregnancy) with an unusual outcome (B. cereus) on an uncommon valve (tricuspid valve).

Bacillus cereus pneumonia in a patient with acute lymphoblastic leukemia

Reported here is a case of Bacillus cereus pneumonia that occurred in a patient with acute lymphoblastic leukemia. The presentation was severe, essentially marked by respiratory distress and pleuritic chest pain. Classic empirical treatment initiated for febrile neutropenia did not cover this rare pathogen and appropriate therapy was therefore delayed. B. cereus is most often a culture contaminant, but it can also be responsible for self-limited gastrointestinal intoxication and, more rarely, severe systemic diseases. Virulence in the case of systemic disease is attributed to tissue necrosis mediated by toxin release. B. cereus pneumonia, as described in the English-language literature, mainly affects immunocompromised patients and most often has a fatal outcome. Thus, the identification of B. cereus in clinical specimens of severely ill immunocompromised patients should lead physicians to question its clinical significance.

Purification and partial characterization of a neutral protease from a virulent strain of Bacillus cereus

The factors involved in the pathogenesis of Bacillus cereus (B. cereus) in non-gastrointestinal diseases are poorly investigated. Some researchers suggest that B. cereus proteases may be involved in these illnesses. The aim of this work was to purify and characterize a protease isolated from a virulent strain of B. cereus to explain its assumptive damaging effect. The enzyme was purified in a four-step procedure involving ammonium sulfate fractionation, acetone precipitation, Bio-Gel filtration and column chromatography on DEAE-cellulose (DE-52 cellulose). The enzyme appeared homogenous using disc electrophoresis. The specific activity of the protease was 72 U/mg of protein. The enzyme was shown to have a relative molecular mass of 29 kDa. The protease was most active at pH 7.0 and 40 degrees C with haemoglobin as the substrate. The enzyme was made completely inactive by ethylenediaminetetraacetic acid (EDTA), beta-mercaptoethanol, dithiothreitol (DTT) and benzamidine (at a concentration of 1 mM) and by diisopropylfluorophosphate (DIPF), L-cysteine, L-histidine, 1,10-phenanthroline (at a concentration of 10 mM). Divalent cations, especially Ca2+ increased enzyme activity. The enzyme hydrolysed haemoglobin, albumin and casein as the substrates. With haemoglobin and albumin as the substrates Michaelis-Menten kinetics was observed. The obtained Km values were 86 +/- 40 microM (SD, n = 3) and 340 +/- 100 microM (SD, n = 3) for haemoglobin and albumin, respectively. The corresponding Vmax values were 1.26 +/- 0.1 (SD, n = 3) and 0.38 +/- 0.07 (SD, n = 3) mumol of tyrosine liberated per min, per ml, and per mg, while those for casein were not determined. It is concluded that this enzyme is a metal-chelator-sensitive, neutral protease damaging haemoglobin and albumin.

Bacillus cereus and related species

Bacillus cereus is a gram-positive aerobic or facultatively anaerobic spore-forming rod. It is a cause of food poisoning, which is frequently associated with the consumption of rice-based dishes. The organism produces an emetic or diarrheal syndrome induced by an emetic toxin and enterotoxin, respectively. Other toxins are produced during growth, including phospholipases, proteases, and hemolysins, one of which, cereolysin, is a thiol-activated hemolysin. These toxins may contribute to the pathogenicity of B. cereus in nongastrointestinal disease. B. cereus isolated from clinical material other than feces or vomitus was commonly dismissed as a contaminant, but increasingly it is being recognized as a species with pathogenic potential. It is now recognized as an infrequent cause of serious nongastrointestinal infection, particularly in drug addicts, the immunosuppressed, neonates, and postsurgical patients, especially when prosthetic implants such as ventricular shunts are inserted. Ocular infections are the commonest types of severe infection, including endophthalmitis, panophthalmitis, and keratitis, usually with the characteristic formation of corneal ring abscesses. Even with prompt surgical and antimicrobial agent treatment, enucleation of the eye and blindness are common sequelae. Septicemia, meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections are other manifestations of severe disease. B. cereus produces beta-lactamases, unlike Bacillus anthracis, and so is resistant to beta-lactam antibiotics; it is usually susceptible to treatment with clindamycin, vancomycin, gentamicin, chloramphenicol, and erythromycin. Simultaneous therapy via multiple routes may be required.

Bacillus cereus meningitis in two neurosurgical patients: an investigation into the source of the organism

Two patients developed Bacillus cereus meningitis following neurosurgery. During the subsequent investigation into the source of the organism, linen was discovered to be heavily contaminated with B. cereus. No other prolific source of the organism was found. It seems probable that lint from contaminated fabric was the vehicle of transmission of the organism during extended surgery. Linen should be considered as a possible source of B. cereus infection.

Criteria for intravitreal antibiotics during surgical removal of intraocular foreign bodies

Published opinion supports the early use of prophylactic antibiotics soon after presentation of a potentially contaminated intraocular foreign body (IOFB) in the posterior segment, preferably within 12 hours of trauma when the visual acuity is still good. Recommended treatment includes topical, subconjunctival, parenteral and especially intravitreal antibiotic therapy to reduce the chance of endophthalmitis. Intravitreal therapy should include gentamicin with vancomycin or clindamycin to cover Bacillus spp., since this organism is responsible for half the endophthalmitis cases and produces beta-lactamase giving resistance to penicillins and cephalosporins. Intravitreal therapy is important because systemic and topical antibiotics do not penetrate the globe in sufficient concentration to control a fulminant infection associated with damaged tissue. Early therapy is essential, as delaying treatment until endophthalmitis occurs is less likely to save useful vision. All vitreous aspirated, plus pus if present, and the IOFB should be cultured for bacteria and fungi to identify pathogens and gain antibiotic sensitivities. The prevention of IOFB-associated endophthalmitis requires early recognition of the IOFB and enthusiastic antibiotic therapy at the time of its removal.