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N-acetylmuramic acid as capping element of alpha-D-fucose-containing S-layer glycoprotein glycans from Geobacillus tepidamans GS5-97T.

Geobacillus tepidamans GS5-97(T) is a novel Gram-positive, moderately thermophilic bacterial species that is covered by a glycosylated surface layer (S-layer) protein. The isolated and purified S-layer glycoprotein SgtA was ultrastructurally and chemically investigated and showed several novel properties. By SDS-PAGE, SgtA was separated into four distinct bands in an apparent molecular mass range of 106-166 kDa. The three high molecular mass bands gave a positive periodic acid-Schiff staining reaction, whereas the 106-kDa band was nonglycosylated. Glycosylation of SgtA was investigated by means of chemical analyses, 600-MHz nuclear magnetic resonance spectroscopy, and electrospray ionization quadrupole time-of-fight mass spectrometry. Glycopeptides obtained after Pronase digestion revealed the glycan structure [-->2)-alpha-L-Rhap-(1-->3)-alpha-D-Fucp-(1-->](n=approximately 20), with D-fucopyranose having never been identified before as a constituent of S-layer glycans. The rhamnose residue at the nonreducing end of the terminal repeating unit of the glycan chain was di-substituted. For the first time, (R)-N-acetylmuramic acid, the key component of prokaryotic peptidoglycan, was found in an alpha-linkage to carbon 3 of the terminal rhamnose residue, serving as capping motif of an S-layer glycan. In addition, that rhamnose was substituted at position 2 with a beta-N-acetylglucosamine residue. The S-layer glycan chains were bound via the trisaccharide core -->2)-alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1--> to carbon 3 of beta-D-galactose, which was attached in O-glycosidic linkage to serine and threonine residues of SgtA of G. tepidamans GS5-97(T).

Bacillaceae↗

Structure and reactivity of a thermostable prokaryotic nitric-oxide synthase that forms a long-lived oxy-heme complex.

In an effort to generate more stable reaction intermediates involved in substrate oxidation by nitric-oxide synthases (NOSs), we have cloned, expressed, and characterized a thermostable NOS homolog from the thermophilic bacterium Geobacillus stearothermophilus (gsNOS). As expected, gsNOS forms nitric oxide (NO) from l-arginine via the stable intermediate N-hydroxy l-arginine (NOHA). The addition of oxygen to ferrous gsNOS results in long-lived heme-oxy complexes in the presence (Soret peak 427 nm) and absence (Soret peak 413 nm) of substrates l-arginine and NOHA. The substrate-induced red shift correlates with hydrogen bonding between substrate and heme-bound oxygen resulting in conversion to a ferric heme-superoxy species. In single turnover experiments with NOHA, NO forms only in the presence of H(4)B. The crystal structure of gsNOS at 3.2 AA of resolution reveals great similarity to other known bacterial NOS structures, with the exception of differences in the distal heme pocket, close to the oxygen binding site. In particular, a Lys-356 (Bacillus subtilis NOS) to Arg-365 (gsNOS) substitution alters the conformation of a conserved Asp carboxylate, resulting in movement of an Ile residue toward the heme. Thus, a more constrained heme pocket may slow ligand dissociation and increase the lifetime of heme-bound oxygen to seconds at 4 degrees C. Similarly, the ferric-heme NO complex is also stabilized in gsNOS. The slow kinetics of gsNOS offer promise for studying downstream intermediates involved in substrate oxidation.

Bacillaceae↗

Characterization of a new thermophilic spore photoproduct lyase from Geobacillus stearothermophilus (SplG) with defined lesion containing DNA substrates.

The Geobacillus stearothermophilus splG gene encodes a thermophilic spore photoproduct lyase (SplG) that belongs to the family of radical S-adenosylmethionine (AdoMet) enzymes. The aerobically purified apo-SplG forms a homodimer, which contains one [4Fe-4S] cluster per monomer unit after reconstitution to the holoform. Formation of the [4Fe-4S] cluster was proven by quantification of the amount of iron and sulfur per homodimer and by UV and EPR spectroscopy. The UV spectrum features a characteristic absorbance at 420 nm typical for [4Fe-4S] clusters, and the EPR data were found to be identical to those of other proteins containing an [4Fe-4S]+ center. Probing of the activity of the holo-SplG with oligonucleotides containing one spore photoproduct lesion at a defined site proved that the enzyme is able to turn over substrate. In addition to repair, we observed cleavage of AdoMet to generate 5'-deoxyadenosine. In the presence of aza-AdoMet the SplG is completely inhibited, which provides direct support for the repair mechanism.

Bacillaceae↗

Three novel halotolerant and thermophilic Geobacillus strains from shallow marine vents.

During a polyphasic taxonomic analysis performed on isolates from shallow marine hydrothermal vents of Eolian Islands (Italy), three thermophilic, halotolerant bacilli, designated as strain 1bw, strain 5-2 and strain 10-1, could not be affiliated to any described species. Physiological and biochemical characteristics, membrane lipids composition, mol % G+C content, and phylogenetic relationships determined on the basis of the 16S rRNA gene sequence analysis, placed these strains within the genus Geobacillus. The three strains were only moderately related to species of Geobacillus and their relatives, members of Saccharococcus. Determination of the relatedness among each other at a higher taxonomic level by DNA-DNA reassociation experiments demonstrated the three isolates to represent three different novel Geobacillus genomospecies. The taxonomic novelty of these three marine strains was substantiated by their physiological properties and by fatty acid patterns that did not match closely those of any Geobacillus type strain. These three novel strains could be of interest to biotechnology because of their ability to produce exopolysaccharides and to adhere on polystirene, characteristics undescribed so far for other Geobacillus species. They are also able to utilise hydrocarbons such as gas oil, kerosene and mineral lubricating oil. Strain 5-2 is tolerant to zinc.

Bacillaceae↗

Bacillus cereus meningitis complicating cerebrospinal fluid fistula repair and spinal drainage.

Non-anthrax Bacillus species are rare, but serious causes of bacterial meningitis in those either immunocompromised or treated with CSF diversion. Although resistant to first-line antibiotics, they usually respond to chloramphenicol. We report a case of fulminant Bacillus cereus meningitis that complicated lumbar spinal drainage which proved resistant to all first-line antibiotics including chloramphenicol.

Adult↗

Acute inflammation and loss of retinal architecture and function during experimental Bacillus endophthalmitis.

Rapid vision loss and explosive inflammation are devastating consequences of Bacillus endophthalmitis that have not been well defined. We therefore analyzed the evolution of intraocular inflammation and loss of retinal architecture and function during experimental Bacillus endophthalmitis. Mice were intravitreally injected with 100 CFU of B. cereus, and eyes were analyzed for bacterial growth, retinal function, architectural changes and retinal cellular stress, inflammatory cytokines, and infiltrating cells. Retinal electrophysiologic and structural changes began as early as 4 to 6 hr postinfection. Significant declines in retinal function paralleled the loss of retinal architecture. Glial fibrillary acidic protein (GFAP) was detected in retina, indicating potential stress. Polymorphonuclear leukocyte (PMN) infiltration into the vitreous began as early as 4 hr postinfection, coinciding with a significant increase in TNF-alpha in the eye. These results indicated that acute inflammation and detrimental architectural and electrophysiologic changes in the retina began earlier than once thought, suggesting that therapeutic intervention should be given at the earliest possible time to avoid vision loss during Bacillus endophthalmitis.

Acute Disease↗

A novel surfactant nanoemulsion with broad-spectrum sporicidal activity against Bacillus species.

Two nontoxic, antimicrobial nanoemulsions, BCTP and BCTP 401, have been developed. These emulsions are composed of detergents and oils in 80% water. BCTP diluted up to 1:1000 inactivated>90% of Bacillus anthracis spores in 4 h and was also sporicidal against three other Bacillus species. This sporicidal activity is due to disruption of the spore coat after initiation of germination without complete outgrowth. BCTP 401 diluted 1:1000 had greater activity than BCTP against Bacillus spores and had an onset of action of <30 min. Mixing BCTP or BCTP 401 with Bacillus cereus prior to subcutaneous injection in mice reduced the resulting skin lesion by 99%. Wound irrigation with BCTP 1 h after spore inoculation yielded a 98% reduction in skin lesion size, and mortality was reduced 3-fold. These nanoemulsion formulas are stable, easily dispersed, nonirritant, and nontoxic compared with other available sporicidal agents.

Animals↗

Infective endophthalmitis caused by Bacillus cereus after cataract extraction surgery.

We describe a 72-year-old Chinese man who developed fulminant Bacillus cereus endophthalmitis 36 h after an uneventful surgery for cataract extraction. Clinical progression of disease was extremely rapid, in spite of early vitrectomy and intravitreal injection of antibiotics. Results of Gram staining showed gram-positive bacilli, and the culture was positive for B. cereus. Endophthalmitis is rare after cataract surgery (cumulative probability within 1 year, approximately 0.08%), and cases caused by B. cereus are even less common. The prognosis and plan of treatment are discussed.

Bacillaceae Infections↗

Persistent Bacillus licheniformis bacteremia associated with an international injection of organic drain cleaner.

In recent years manufacturers have developed several products containing saprophytic bacteria, previously believed to be of minimal pathogenicity. We describe the first case of persistent Bacillus licheniformis bacteremia occurring after intentional injection of a consumer product that includes B. licheniformis spores. We postulate that these spores remained in the tissue, unaffected by antimicrobials, ultimately necessitating soft-tissue debridement of the area surrounding the injection site. On the basis of this case and a review of the literature, we submit that some consumer products contain bacteria with demonstrated pathogenicity. Manufacturers should study these bacteria in detail in order to rapidly provide information such as bacteriologic data and antimicrobial susceptibility data to clinicians.

Adult↗

Dissemination of Bacillus cereus in an intensive care unit.

OBJECTIVE: To report the contamination of ventilator equipment with Bacillus cereus and to outline the measures taken to trace the source of the organism. DESIGN: A prospective survey of all intensive care unit patients who were culture-positive for B cereus and obtaining of environmental cultures of the cleaning and assembly area of the respiratory services division between October 1991 and September 1992. SETTING AND PATIENTS: Ventilated patients from a 16-bed medical and surgical intensive care unit (ICU) in a 1,000-bed adult tertiary care hospital. INTERVENTIONS AND RESULTS: From October 1991 to April 1992, B cereus colonized the ventilator circuitry of patients in the ICU. One of two washer/decontaminators in the cleaning and assembly area of the respiratory services division was found to yield the microorganism consistently from the water intake port. The design of the machine precluded easy decontamination of the port with 2% glutaraldehyde and a second outbreak occurred. Following the second outbreak, aqueous chlorhexidine in a final concentration of 0.05% was added to the first of two pasteurization cycles in an attempt to achieve sporicidal activity. This ended the outbreak. Sixty-two patients became colonized with the organism including two with nonfatal Bacillus sepsis and one death due to pneumonia associated with the organism. CONCLUSION: This experience emphasizes the importance of obtaining cultures of machine parts to identify the source of contamination and thereby direct control measures. Use of chlorhexidine gluconate at high temperatures effectively eradicated B cereus from ventilator circuitry in a practical and cost-effective manner.

Bacillaceae Infections↗

An outbreak of Bacillus species in a cancer hospital.

Bacillus species were recovered from the blood cultures of 39 oncology patients over 14 weeks. A matched case-control study showed a strong association of Bacillus species bacteremia with use of calcium gluconate solution (odds ratio=25.0) and of central venous lines (odds ratio=8.8). Stopping use of the implicated calcium gluconate vials controlled the outbreak.

Adolescent↗

Molecular mechanisms of Bacillus endophthalmitis pathogenesis.

Bacillus endophthalmitis is one of the most devastating intraocular infections, frequently resulting in significant vision loss, if not loss of the eye itself, in only a few days. This review summarizes recent research focused on characterizing the interactions between Bacillus and the host response during endophthalmitis. Analyses of the contribution of Bacillus toxins and cell wall components, and the behavior of the organism during progressive disease are discussed. A better understanding of the host/pathogen interactions occurring during endophthalmitis is critical for the development of novel therapeutic agents designed to impede the progression of infection and protect vision.

Bacillaceae Infections↗

Comparison of "gram-sure" with vancomycin disks in distinguishing between gram-negative and gram-positive rods.

A study was performed to compare Gram-Sure (JRGA Diagnostics, Rancho Dominguez, CA) with vancomycin disk susceptibility (5 micrograms and 30 micrograms) for clarification of the Gram reaction. Eighty-eight isolates representing 14 gram-negative and gram-positive genera were tested. Gram-Sure was superior to vancomycin susceptibility as a predictor of the Gram reaction in a select group of difficult organisms.

Bacillaceae Infections↗

Significant infections due to Bacillus species following abrasions associated with motor vehicle-related trauma.

Non-anthracis Bacillus species are ubiquitous gram-positive spore-forming organisms that were once believed to be nonpathogenic but are now recognized as causing a variety of infections. We report a new aspect of trauma associated with bacillus infection: clinically significant infection by Bacillus species in patients who are involved in motor vehicle accidents and sustain injury related to road contact. Cases were evaluated retrospectively from May 1990 through December 1991. Four patients who had documented infections with Bacillus species and who were involved in motor vehicle accidents associated with road trauma were identified during this period. The antibiotic susceptibility profile of the Bacillus species consistently demonstrated resistance to beta-lactam antibiotics. This series of cases illustrates an additional aspect of disease associated with bacteria of the Bacillus species that should be considered for patients who have sustained injuries from motor vehicle accidents associated with road trauma.

Accidents, Traffic↗

Systemic Bacillus species infection mimicking listeriosis of pregnancy.

Bacillus species are increasingly recognized as agents of infection in humans. These organisms are ubiquitous in nature and can cause clinical illness ranging from transient bacteremia to serious systemic infection. We describe a pregnant intravenous drug abuser with fever, constitutional symptoms, and premature labor. Her blood cultures yielded gram-positive bacilli, and her clinical course was consistent with systemic listeriosis of pregnancy. Pathological examination of the placenta revealed acute villitis, and Bacillus species grew from cultures of both placenta and blood. Through biochemical testing the isolate was identified as Bacillus pumilis. To our knowledge, this is the first reported case of premature labor induced by Bacillus species infection.

Adult↗