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.

Bacillus spp. among hospitalized patients with haematological malignancies: clinical features, epidemics and outcomes

Between April 2000 and May 2005, 350 bacteraemic episodes occurred among patients treated in our haematology unit. Two hundred and twenty-eight of these episodes were caused by Gram-positive pathogens, most commonly coagulase-negative staphylococci and Staphylococcus aureus. One hundred and twenty-two episodes were due to Gram-negative pathogens, with a predominance of Escherichia coli, Acinetobacter baumannii and Pseudomonas aeruginosa. Bacillus bacteraemias constituted 12 of these episodes occurring in 12 patients, and accounted for 3.4% of all bacteraemic episodes. Of the 12 strains evaluated, seven were Bacillus licheniformis, three were Bacillus cereus and two were Bacillus pumilus. Seven episodes presented with bloodstream infection, three with pneumonia, one with severe abdominal pain and deterioration of liver function, and one with a catheter-related bloodstream infection. B. licheniformis was isolated from five patients who had been hospitalized at the same time. This outbreak was related to non-sterile cotton wool used during skin disinfection. B. cereus and B. licheniformis isolates were susceptible to cefepime, carbapenems, aminoglycosides and vancomycin, but B. pumilus isolates were resistant to all antibiotics except for quinolones and vancomycin. Two deaths were observed. In conclusion, Bacillus spp. may cause serious infections, diagnostic and therapeutic dilemmas, and high morbidity and mortality in patients with haematological malignancies. Both B. cereus and B. licheniformis may be among the 'new' Gram-positive pathogens to cause serious infection in patients with neutropenia.

Identification of novel eubacteria from spent mushroom compost (SMC) waste by DNA sequence typing: ecological considerations of disposal on agricultural land

A small study was undertaken to examine the microbiological characteristics of spent mushroom compost (SMC), which is the major waste by-product of the mushroom industry and which is regularly disposed off by application to agricultural land. The primary aim of this study was to examine SMC for the presence of faecal bacterial pathogens, including Campylobacter spp., Salmonella spp. and Listeria monocytogenes. Secondly it was desirable to quantify bacterial and fungal populations within SMC, and also qualitatively identify the diversity of bacterial populations within SMC, through employment of rDNA PCR and direct sequencing techniques on the culturable microflora. Conventional microbiological analyses of SMC material (n=30) from six commercial operations in both Northern Ireland and the Republic of Ireland, failed to detect Salmonella spp, Listeria spp. or Campylobacter spp. in any of the SMC material examined. Total aerobic plate counts gave a mean count of log10 7.01 colony forming units (cfu) per gram SMC material (range: log10 6.53-7.52 cfu/g). Fungal counts gave a mean count of log(10) 4.57 cfu per gram SMC material (range: log10 3.93-4.98 cfu/g). From a total of greater than 50 colony picks, a total of 12 bacterial morphotypes were identified and were further examined by employment of partial 16S rRNA gene amplification and sequencing techniques, yielding several genera and species, including Bacillus licheniformis, Bacillus subtilis, Klebsiella/Enterobacter sp. Microbacterium sp. Paenibacillus lentimorbus, Pseudomonas mevalonii, Sphingobacterium multivorum and Stenotrophomonas sp. This is the first preliminary report on the microbial diversity of SMC waste and demonstrates the presence of several species that have not been previously described in SMC, in addition to two potentially novel species within the genera Microbacterium and Stenotrophomonas. It is thereby important to examine the ecological microbe-microbe and plant-microbe interactions that are occurring between the native bacterial soil flora and those added annually (theoretically estimated at approximately 10(18) cells) through the application of SMC. Such studies would be beneficial in helping to ascertain the ecological consequences involved in the disposal of SMC waste on agricultural land.

Bacillus cereus infections among oncology patients at a children's hospital

BACKGROUND

Bacillus cereus can cause severe infections in immunocompromised persons.

METHODS

We report 3 cases of bacteremia/septicemia (1 fatal) among oncology patients in a children's hospital. Because all cases occurred during a 10-day period, a common source outbreak was suspected. An epidemiologic investigation was performed. Molecular comparison of patient and environmental isolates was performed by using pulsed-field gel electrophoresis.

RESULTS

After an extensive investigation, no common hospital source could be found. Pulsed-field gel electrophoresis proved that the isolates were not related.

CONCLUSION

Sporadic infections in immunocompromised persons do occur and can be associated with significant morbidity.

Fulminant septicaemic syndrome of Bacillus cereus: three case reports

Three patients with acute leukaemia, who were severely neutropenic and iatrogenically immunosuppressed post-chemotherapy, developed rapidly fatal septicaemic shock and coma caused by Bacillus cereus (B. cereus). The illness was marked by two phases: a mild febrile illness lasting 6-14 h and accompanied by subtle symptoms of autonomic sympathetic nervous system overactivity, and a second short fulminant one, marked by high fever of 40-41 degrees C accompanied by major central nervous system disturbances, and ending with deep coma and brain stem dysfunction. One patient developed the sepsis in spite of 4 days of coverage with amikacin. In the other two patients, amikacin was commenced at the earliest phase of the infection, but failed to influence the outcome. This form of B. cereus sepsis in neutropenic patients seems to be caused by strains capable of causing bacteraemia and meningitis and has the ability to produce a substance that causes leptomeningeal and neuronal necrosis. Lack of early clinical and laboratory markers inevitably leads to death. Use of antibiotics effective against B. cereus and capable of achieving high concentrations in the cerebrospinal fluid. and identification and neutralization of the necrotizing substance may hopefully help to reverse this fatal illness.

Prosthetic heart valve endocarditis caused by Bacillus circulans

We report a case of prosthetic valve endocarditis due to Bacillus circulans in a 56-year-old woman. Pre-operative blood cultures were negative and the organism was only recovered on culture of the explanted mechanical valve. We discuss the reasons for the late clinical presentation of this case, 15 months post valve replacement, caused by an organism which is conventionally regarded as 'early' pathogen. The patient recovered well post surgery on a 6 week course of trimethoprim and ciprofloxacin.

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.

Growth and enterotoxin production by diarrhoeagenic Bacillus cereus in dietary supplements prepared for hospitalized HIV patients

This study was initiated because of an increase in diarrhoeal episodes in a ward caring for patients infected with the human immunodeficiency virus (HIV). An examination of hospital-prepared dietary supplements (build-up food) found Bacillus cereus to be a potential problem. Due in part to inadequate refrigeration conditions (13 +/- 4 degrees C), the microbial flora in commercially pasteurized semi-skimmed milk (PSSM) reached potentially hazardous levels (> 10(6) cfu/mL). While refrigerated PSSM did not support enterotoxin production, reconstitution of build-up powder in PSSM followed by storage in the HIV ward (4 h at 28 +/- 3 degrees C) resulted in growth of B. cereus (> 10(7) cfu/mL) and synthesis of diarrhoeal enterotoxin. While insufficient epidemiological data was available to establish conclusively a causal relationship between patients' symptoms and source, the study highlights a potential B. cereus problem with hospital-prepared dietary supplements and recommendations are proposed to prevent this re-occurrence.

Catheter-related complications of cancer therapy

Although the management of CVC-related infection appears complex and at times the literature seems to be contradictory, simple guidelines can direct the clinician in a stepwise fashion. Knowledge of the pathogenesis of each organism and the immune status of the host is crucial to decide whether catheter removal or retention is indicated. For example, in general, GNB bacteremia does not immediately prompt catheter removal in a neutropenic patient but does in a nonneutropenic host because of the gastrointestinal source of the former and a primary catheter source in the latter. In summary, as more CVCs are inserted in patients undergoing chemotherapeutic, antimicrobial, transfusional, and nutritional supportive care, novel approaches to prevention and treatment of the associated infectious complications inherent with such devices are needed. A multifaceted approach from impregnated catheters to local catheter-site antisepsis was reviewed. We may find, however, that as simple handwashing between patients is crucial to infection control, so too is a trained catheter-care team using total barrier precautions and ensuring proper local catheter maintenance critical to preventing CVC-related infections.