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Bacillus endophthalmitis: roles of bacterial toxins and motility during infection.

PURPOSE: Bacillus endophthalmitis is a highly explosive infection of the eye that commonly results in rapid inflammation and vision loss, if not loss of the eye itself, within a few days. Quorum-sensing-controlled toxins are essential to virulence during infection. Another unique characteristic of this disease is the ability of Bacillus to replicate rapidly and migrate to all parts of the eye. This study was conducted to determine the combined roles of toxins and motility during Bacillus endophthalmitis. METHODS: Rabbit eyes were injected intravitreally with approximately 100 cfu of wild type, nonmotile, or nonmotile/quorum-sensing-deficient Bacillus thuringiensis. Infection courses were analyzed by biomicroscopy, histology, electroretinography, and quantitation of bacteria and inflammatory cells. RESULTS: Infection with wild type B. thuringiensis resulted in complete retinal function loss by 18 hours after infection, whereas nonmotile B. thuringiensis infections required 30 hours to achieve a reduction of >90% in retinal function. Further attenuation of infection resulted from infection with the nonmotile/quorum-sensing-deficient B. thuringiensis strain, with approximately 90% retinal function loss occurring at 36 hours. Overall, the nonmotile and nonmotile/quorum-sensing-deficient mutants were significantly less virulent than wild-type B. thuringiensis. CONCLUSIONS: The results demonstrate that, in addition to quorum-sensing-controlled toxin production, bacterial migration within the eye contributed to the rapidly fulminant and destructive course of Bacillus endophthalmitis. Motility and quorum-sensing may therefore represent possible targets for the development of therapies designed to attenuate the devastating effects of Bacillus in the eye during endophthalmitis.

Animals↗

Isolation of cilia-associated respiratory (CAR) bacillus from pigs and calves and experimental infection of gnotobiotic pigs and rodents.

Filamentous, gram-negative bacteria morphologically similar to cilia-associated respiratory (CAR) bacillus of rodents and rabbits were isolated from the tracheas of 5 pigs and 4 calves. All pigs but none of the calves had histologic lesions of chronic tracheitis. In silver-stained histologic sections, CAR bacilli were adhered to the tracheal epithelium of each pig but were not found in the calves. Like CAR bacillus of rats, the bacteria displayed gliding motility and grew only in cell culture or cell culture medium supplemented with fetal serum. Initially, all isolates were contaminated by Mycoplasma spp. This contamination was eliminated from 4 pig isolates by limiting dilutions, and mycoplasma-free isolates were used to intranasally inoculate gnotobiotic pigs and CAR bacillus-free mice and rats and to immunize guinea pigs. The gnotobiotic pigs remained healthy, and when they were necropsied 4 and 7 weeks after infection no macroscopic or microscopic lesions were found in the respiratory tract. However, CAR bacillus was isolated at both times from the nasal cavities and tracheas of inoculated pigs, and the ciliated tracheal epithelium of infected pigs necropsied 7 weeks after infection was colonized by low numbers of CAR bacillus-like bacteria. The rats and mice remained healthy through week 12 postinoculation, and evidence of short- or long-term colonization was not detected by histologic examination or culture. When used as primary antibody for immunohistochemical staining, sera from guinea pigs immunized with pig CAR bacillus specifically stained CAR bacilli colonizing the respiratory epithelium of naturally infected pigs, whereas sera collected prior to immunization failed to react with the bacteria. These results indicate that CAR bacilli are unlikely to be primary pathogens of pigs or cattle and that rodents do not act as reservoirs.

Animals↗

Establishing the independent culture of a strictly symbiotic bacterium Symbiobacterium thermophilum from its supporting Bacillus strain.

Symbiobacterium thermophilum is a strictly symbiotic thermophile, the growth of which is dependent on the coexistence of an associating thermophilic Bacillus sp., strain S. S. thermophilum grows only in mixed culture with the Bacillus strain in liquid media, and does not form visible colonies on solid media. To measure the growth of this symbiotic bacterium and to analyze its growth requirements, we developed a quantitative PCR method by using its specific sequences in a putative membrane translocator gene tnaT as primers. According to this method, independent growth of S. thermophilum was first confirmed in a dialyzing culture physically separated from Bacillus strain S with a cellulose membrane. Independent growth of S. thermophilum was also managed by adding conditioned medium prepared from the culture filtrate of the Bacillus strain, but the growth in the conditioned medium stopped at a very limited extent with appearance of filamentous cells, suggesting the uncoupling of cellular growth and cell division. Formation of micro-colonies of S. thermophilum was observed on the conditioned agar medium under both aerobic and anaerobic conditions, but the colony-forming efficiencies remained below 1%. Several other bacterial species, such as Bacillus stearothermophilus, Bacillus subtilis, Thermus thermophilus, and even Escherichia coli, were also found to support the growth of S. thermophilum. These results indicate that S. thermophilum essentially requires some ubiquitous metabolite(s) of low molecular weight produced by various bacterial species as growth factor(s) but coexistence of the living partner cells is still required, probably to maintain an effective level of the putative factor(s) in the medium.

Bacillus↗

Thermal resistance of spores from virulent strains of Bacillus anthracis and potential surrogates.

The objective of this study was to determine the thermal resistance of spores of Bacillus anthracis and potential surrogates. The heat resistance of spores suspended in buffer (pH 7.0 or 4.5), milk, or orange juice was determined at 70, 80, and 90 degrees C. D-values for B. anthracis strains Sterne, Vollum, and Pasteur ranged from < 1 min at 90 degrees C to approximately 200 min at 70 degrees C and were lower under acidic than under neutral conditions. The D-values for B. anthracis spores fell within the range obtained for spores from eight strains of Bacillus cereus, Bacillus thuringiensis, Bacillus mycoides, and Bacillus subtilis. However, there were significant differences (P < 0.001) among the D-values of the strains. The z-values in pH 7.0 buffer and milk averaged approximately 10.5 degrees C and were not significantly different among strains (P < 0.05). The z-values in pH 4.5 buffer and orange juice averaged 12.9 and 13.9 degrees C, respectively, significantly (P < 0.05) higher than those obtained in milk or in pH 7.0 buffer. The significance of this difference was driven by large differences among a few strains. The z-values for B. anthracis strain Pasteur were twice as high in the acid media than in the neutral media. This study confirms that B. anthracis spores are not unusually heat resistant and that spores from validated Bacillus species are appropriate surrogates for thermal resistance studies.

Bacillus anthracis↗

[Sequencing of a beta-amylase gene from Bacillus firmus].

The gene encoding a beta-amylase from Bacillus firmus 725 was sequenced. The sequenced DNA of 2012 bp contains one open reading frame of 1406 nucleotides without a translation stop codon. The deduced amino acid sequence homology with those known bacterial and some plant beta-amylase was 98% for Bacillus polymyxa 72, 98% for Bacillus polymyxa ATCC8523, 82% for Bacillus circulans, 54% for Clostridium thermosulfurogenes, 49% for Bacillus cereus BQ10-S1, 50% for Bacillus cereus var. mycoides, 36% for barley, and 36% for soybean Eleven well-conserved regions were found among the amino acid sequences of the nine beta-amylases.

Amino Acid Sequence↗

[Studies on the ecological distribution of Bacillus thuringiensis in forest soils of China].

A total of 384 forest soils samples at 0-5cm depth collected from 8 forest site zones (13 Natural Reserves) in China were examined for the distribution of Bacillus and Bacillus thuringiensis. The 79 cultures (4.21%) in 1873 isolates of Bacillus collected referable to the Bacillus thuringiensis. Soil pH, moisture content and soil nutrient were determined. Rules of the ecological distribution of Bacillus thuringiensis of 8 forest site zones in China were analysed. Toxicities against 6 species of insect were tested. Strain some efficient serains were obtained. It was shown that resource of Bacillus thuringiensis is much fruitful in forest soils of China.

Bacillus thuringiensis↗

Studies on the composition and properties of thermophilic Bacillus populations in subterranean thermal waters of Budapest (Hungary).

A collection of 148 thermophilic Bacillus isolates were obtained from two thermal wells (water temperature at about 70 degrees C) in the area of Budapest (Hungary). These isolates, furthermore seven authentic thermophilic reference strains of Bacillus spp. were submitted to detailed comparative biochemical-physiological studies. Overall similarities of these strains for 134 unit characters were determined by the SSM coefficient and clustering achieved using the UPGMA algorithm. According to the results of our computer aided numerical taxonomic analyses, numerous metabolic types, varieties and mutants of a single Bacillus sp. not identical with the known thermophilic Bacillus species constitute the major fraction of the indigenous thermophilic microbial communities in the thermal waters of the Pascal and Széchenyi wells. The data also revealed, (1) that the most adapted varieties of this Bacillus sp. can form the most dense local populations in these subterranean ecological systems. Furthermore, it seems to be probable (2) that the cells of the most commonly occurring varieties of this Bacillus sp. may be able to migrate in the underground thermal water systems between diverse subterranean regions located more or less far from one another.

Bacillus↗

Inhibition of the growth of Ascosphaera apis by Bacillus and Paenibacillus strains isolated from honey.

The fungus Ascosphaera apis, the causative agent of chalkbrood disease in honeybee larvae, occurs throughout the world and is found in many beekeeping areas of Argentina. The potential as biocontrol agents of 249 aerobic spore-forming bacterial antagonists isolated from honey samples was evaluated. Each isolate was screened against A. apis by a central disk test assay. Ten bacterial strains that showed the best antagonistic effect to A. apis were selected for further study and identified as Bacillus cereus (m363, mv86, mv81, mv75), Bacillus circulans (Fr231, m448b), Bacillus megaterium (m435), Bacillus pumilus (m354), Bacillus subtilis (m329), and Paenibacillus alvei (m321). For testing the efficiency of the selected strains, a paired culture test was used with 5 replicates of each combination bacterial antagonist/A. apis strain, and 5 replications for each control on 4 different culture media. The analysis of variance and posterior comparison of means according to LSD method showed that the best antagonists when using YGPSA medium were B. subtilis (m329) and B. megaterium (m435), and in the case of MYPGP medium the most efficient were B. circulans strains Fr 231 and m448b.

Animals↗

Reversibility of azoospermia induced by bacillus Calmette-Guerin.

A single intratesticular injection of bacillus Calmette-Guerin induces azoospermia within 3 to 6 weeks in a variety of animals without loss of androgens. After a period of azoospermia, the return of spermatogenesis was observed in dogs and monkeys. Seven dogs that showed aspermatogenesis after a local instillation of bacillus Calmette-Guerin (20-110 units per testis) again demonstrated spermatogenesis after a period of 153 to 325 days of azoospermia. Sperm counts and motility were restored to preimmunization levels within 6 weeks after initiation of spermatogenesis. In one dog, systemic treatment with antimycobacterial drugs helped to clear the bacillus Calmette-Guerin from the testis, thus hastening the reinitiation of spermatogenesis. In two monkeys injected with 110 and 160 units of bacillus Calmette-Guerin, azoospermia lasted up to 150 days. Subsequently, fertility was restored and the treated animals sired healthy offspring. A second injection of bacillus Calmette-Guerin of a lesser dose (5-20 units per testis) in these fertile dogs and monkeys again produced azoospermia. Histologically, the monkeys having a second period of azoospermia demonstrated aspermatogenic orchitis in the testis and leukocyte infiltration in the interstitium. A majority of the tubules had intact basement membranes, with a block of spermatogenesis at the spermatocyte stage. In dogs, the second azoospermia lasted for 113 to 277 days with a subsequent restoration of sperm counts and sperm motility to preimmunization levels. There were no circulating antisperm antibodies detected in sera of these animals during the azoospermic period or during its reversal. These observations suggest that the bacillus Calmette-Guerin-induced azoospermia is reversible, both in terms of sperm count and fertility.

Animals↗

Enhancement of bacillus Calmette-Guerin attachment to the urothelium by removal of the rabbit bladder mucin layer.

It has been established that the urothelial mucin layer functions as a bacterial anti-adherence factor. Intravesical Bacillus Calmette-Guerin is used to treat patients with superficial bladder cancer. The proposed mechanism of action of Bacillus Calmette-Guerin is adherence to the urothelium with induction of an immunologic and/or inflammatory response. The current study was designed to determine if rabbit bladder mucin removal results in increased Bacillus Calmette-Guerin urothelial adherence. PAS and colloidal iron stains were used to demonstrate that intravesical instillation of 50% acetone renders rabbit bladder urothelium mucin deficient. The urothelium remains mucin deficient at two hours, but by 24 hours the mucin layer has been regenerated. Two hours following intravesical 3H-labeled Escherichia coli administration, bacterial adherence was 29-fold greater in mucin deficient than mucin intact rabbits (p = 0.05). By 12 hours, the difference in adherence was not significant. Two hours following intravesical administration of 3H-labeled Bacillus Calmette Guerin, mucosal adherence was 21-fold greater in mucin deficient compared to mucin intact rabbits (p = 0.002). After mucin removal, Bacillus Calmette Guerin urothelial adherence was significantly increased. The significant increase in Bacillus Calmette Guerin adherence after mucin removal may be clinically exploitable.

Animals↗

Choice of an optimal diluent for intravesical bacillus Calmette-Guerin administration.

The physical conditions, including diluent pH, salt concentration and duration of bacillus Calmette-Guerin attachment, were determined in in vitro binding assays for soluble and matrix fibronectin. Since soluble fibronectin may block attachment of bacillus Calmette-Guerin to matrix fibronectin in the bladder, the optimal conditions were determined under which matrix fibronectin-bacillus Calmette-Guerin binding was maximal and soluble fibronectin-bacillus Calmette-Guerin binding was minimal. These conditions, which were confirmed in vivo in the murine bladder model, included use of normal saline, pH 7 as diluent for bacillus Calmette-Guerin organisms, with retention of the bacillus Calmette-Guerin suspension for 2 hours.

Administration, Intravesical↗

Long-term followup of patients treated with 1 or 2, 6-week courses of intravesical bacillus Calmette-Guerin: analysis of possible predictors of response free of tumor.

We report our long-term experience with 104 patients treated for recurrent superficial bladder tumors followed for a mean of 48 +/- 2 months (range 6 to 83 months). Patients received 6 weekly intravesical bacillus Calmette-Guerin instillations, and were followed for response with urinary cytology, cystoscopy and bladder biopsy. Patients were considered treatment failures if either urinary cytology or biopsy results were positive for tumor. Of 69 patients who failed the initial treatment course 60 were given an additional 6-week course of therapy. A 6-week course of bacillus Calmette-Guerin was successful in 19 of 55 patients (35%) treated for prophylaxis, 10 of 32 (31%) treated for carcinoma in situ and 6 of 17 (35%) treated for residual tumor. The response rate for the total patient population treated with 1, 6-week course was 34% (35 of 104). Another 6-week course was successful in 32 of 60 patients (53%). The over-all response rate free of tumor for patients treated with either 6 or 12 weeks of therapy was 64%. The mean interval free of tumor was 48 months. We evaluated tumor type, stage and grade in conjunction with muscle invasion to assess potential indicators of response to a second course of bacillus Calmette-Guerin. Of 13 patients with carcinoma in situ and 45 with papillary disease 5 (38%) and 26 (58%), respectively, responded to a second course of bacillus Calmette-Guerin (not significantly different). In contrast, 5 of 8 carcinoma in situ failures (63%) had muscle invasive disease, compared to only 3 of 19 papillary nonresponders (16%) (p less than 0.02). These results suggest that intravesical bacillus Calmette-Guerin for the treatment of superficial bladder tumors is an effective long-term therapy. One 6-week course may be ineffective for some patients and another 6-week course provides long-term survival free of tumor for many course 1 failures. Patients who present with carcinoma in situ after a single 6-week course of intravesical bacillus Calmette-Guerin have a significantly higher risk for muscle invasive disease than those with recurrent papillary tumors.

Administration, Intravesical↗

Results of 6 weekly intravesical bacillus Calmette-Guerin instillations on the treatment of superficial bladder tumors.

We evaluated 104 patients with superficial bladder tumors for response to intravesical bacillus Calmett-Guerin therapy. Patients received 6 weekly intravesical bacillus Calmette-Guerin instillations and they were followed for response every 3 months with urinary cytology, cystoscopy and bladder biopsy. Patients were considered treatment failures if either the cytology studies or biopsies were positive for tumor. Of 65 patients who failed the initial treatment course 57 were given an additional 6-week course of therapy. One 6-week course of bacillus Calmette-Guerin was successful in 20 of 55 patients (36 per cent) treated for prophylaxis, 12 of 32 (37 per cent) treated for carcinoma in situ and 7 of 17 (41 per cent) treated for residual tumor. The response rate for the total patient population treated with 1, 6-week course was 37.5 per cent (39 of 104). A second 6-week course was successful in 19 of 29 patients (65 per cent) treated for prophylaxis, 11 of 18 (71 per cent) treated for carcinoma in situ and 4 of 10 (40 per cent) treated for residual tumor. The response rate for all patients receiving a second course of bacillus Calmette-Guerin was 59.6 per cent (34 of 57). Of 6 patients who refused another 6-week course of bacillus Calmette-Guerin 4 had additional recurrences and 3 of these 4 suffered invasive disease. The over-all therapeutic response rate for patients treated with either 6 or 12 weeks of therapy was 70 per cent. These results suggest that 6 weeks of intravesical bacillus Calmette-Guerin do not provide optimal therapy for superficial bladder tumors. The data further suggest that more intensive regimens may increase therapeutic efficacy.

Administration, Intravesical↗

Comparison of the efficacy of intravesical Bacillus Calmette-Guérin with thiotepa, mitomycin C, poly I:C/poly-L-lysine and cis platinum in murine bladder cancer.

The efficacy of intravesical Bacillus Calmette-Guérin for the treatment of the mouse bladder tumor MBT-2 was compared with that of thiotepa, mitomycin C, cis-diamminedichloroplatinum II and poly I:C/poly-L-lysine. MBT-2 cells were instilled into the bladder immediately after electrocauterization. Drug instillations were initiated 24 hours later and continued on a weekly basis for 4 weeks. Both Bacillus Calmette-Guérin and cis-diamminedichloroplatinum II significantly (p less than .0004) inhibited MBT-2 tumor implantation when compared to diluent-treated controls. Neither mitomycin C, thiotepa nor poly I:C/poly-L-lysine significantly inhibited tumor implantation. Mean tumor weights also were significantly (p less than .05) reduced in Bacillus Calmette-Guérin and cis-diamminedichloroplatinum II-treated mice, while tumor mean weights in mice treated with thiotepa, mitomycin C or poly I:C/poly-L-lysine were not significantly different than controls. These results suggest that the efficacy of intravesical Bacillus Calmette-Guérin in comparison with other drugs in the MBT-2 mouse bladder tumor model is similar to observations reported in human clinical trials in which intravesical Bacillus Calmette-Guérin was shown to be more effective than other cytotoxic drugs. These data further support the utility of the MBT-2 model for the study of the mechanisms by which Bacillus Calmette-Guérin inhibits bladder tumor growth.

Administration, Topical↗

Isolation, propagation, and characterization of a newly recognized pathogen, cilia-associated respiratory bacillus of rats, an etiological agent of chronic respiratory disease.

A Gram-negative, filamentous, rod-shaped bacillus which failed to grow in cell-free media was isolated in apparently pure culture from the bronchial scraping and washing of a laboratory rat suffering from chronic respiratory disease by inoculating embryonated chicken eggs via the allantoic route. None of the embryos died during 20 serial passages at weekly intervals. The bacillus was reisolated in embryonated eggs from cesarean-derived barrier-maintained N:SD(SD) rats 8 and 12 weeks after intranasal inoculation with 10th-passage allantoic fluid. The inoculated rats were housed in Horsfall-type units and remained free from other known respiratory pathogens, including mycoplasmas and murine viruses, throughout the study. The bacillus colonized the ciliated epithelial cells of the respiratory tract and caused a marked peribronchial infiltration and hyperplasia of mononuclear cells which progressed with time. The bacillus, ca. 0.2 micron wide by 4 to 6 micron long, stained very poorly with basic aniline dyes but was readily demonstrated with the Warthin-Starry silver technique. It was heat labile (56 degrees C for 30 min); spore forms were not observed. It withstood freeze-thawing and was successfully stored at -70 degrees C. Although no visible means of locomotion was observed with the electron microscope, a slow gliding motility, sometimes with bending and flexing of bacilli apparently adherent to the glass surface, was observed with phase microscopy. As an etiological agent of chronic respiratory disease of rats, this cilia-associated respiratory bacillus (tentatively designated the CAR bacillus) may be the first recognized gliding bacterium known to cause disease in a warm-blooded vertebrate.

Animals↗

16S rRNA sequences of Bartonella bacilliformis and cat scratch disease bacillus reveal phylogenetic relationships with the alpha-2 subgroup of the class Proteobacteria.

The primary structures of 16S rRNAs of Bartonella bacilliformis, an isolate of the cat scratch disease (CSD) bacillus, and a strain phenotypically similar to the CSD bacillus were determined by reverse transcriptase sequencing. These microorganisms were found to be members of the alpha-2 subgroup of the class Proteobacteria. The sequence from B. bacilliformis was most closely related to the rRNA of Rochalimaea quintana (91.7% homology), the etiologic agent of trench fever. The sequence from the isolate of the CSD bacillus showed the greatest homology with Brucella abortus (89.7%) and, when compared with oligonucleotide catalog data, formed a cluster with Rhodopseudomonas palustris, Pseudomonas carboxidovorans, Nitrobacter species, and Bradyrhizobium species. The 16S rRNA sequence was also determined for the Cleveland Clinic isolate, which was previously shown to be phenotypically similar to and approximately 30% related, by DNA hybridization, to the CSD bacillus. The Cleveland Clinic isolate was isolated from a patient not diagnosed with CSD. The rRNAs from these bacteria exhibited 98.2% homology, confirming that this isolate is a second species in the same genus as the CSD bacillus. Our data suggest that neither B. bacilliformis nor the CSD bacillus is the etiologic agent of bacillary epithelioid angiomatosis.

Alphaproteobacteria↗

Detection of cilia-associated respiratory bacillus by PCR.

The cilia-associated respiratory (CAR) bacillus is an unclassified, gram-negative, motile bacterium that has been implicated as an etiologic agent of respiratory disease in laboratory rodents. In the present study, approximately 1,200 bases of the 16S rRNA gene from three CAR bacillus isolates were sequenced. CAR bacillus-specific primers were designed on the basis of the 16S rRNA gene sequence and used in a PCR assay. The PCR assay detected as little as 500 fg of purified CAR bacillus DNA. The expected 267-bp DNA fragment was amplified from respiratory tissue of frozen, formalin-fixed, and paraffin-embedded samples from experimentally and naturally infected rats and mice. In contrast, no product was amplified from respiratory tissues of sham-infected experimental animals or animals that were serologically or histopathologically negative for the CAR bacillus. Our findings indicate that this PCR assay is a rapid, specific, and sensitive detection method for the diagnosis of CAR bacillus infection in rats and mice.

Animals↗

Detection of Mycoplasma pulmonis in cilia-associated respiratory bacillus isolates and in respiratory tracts of rats by nested PCR.

To improve the detection of Mycoplasma pulmonis contamination of isolates of cilia-associated respiratory (CAR) bacillus, we developed a nested PCR method using primers for 16S rRNA gene sequences. Of 140 samples of 16 different CAR bacillus isolates, 73 (52%) were inhibitory in the first PCR, as indicated by the absence of amplicons of the internal control, but only 11 of 140 (7.9%) were inhibitory in the second PCR. Of 27 samples known to contain M. pulmonis, only 12 (44%) were positive in the first PCR, but 25 of 27 (93%) were positive in the second PCR. Nested PCR also detected M. pulmonis in 21 of 61 (34%) CAR bacillus samples from which M. pulmonis could not be cultured and identified 2 additional M. pulmonis-contaminated CAR bacillus isolates. Of 359 respiratory and reproductive tract lavage samples from rats and mice, 35 (9.8%) were inhibitory in the first PCR, but only 15 (4.2%) were inhibitory in the second PCR. Of 72 lavage specimens from rats inoculated with an avirulent, poorly infective M. pulmonis strain, 14 (19%) were positive by nested PCR, but only 2 of 72 (2.8%) were positive by culture. Nested PCR also detected M. pulmonis in 14 of 20 (70%) paraffin sections of lung and trachea from rats and mice inoculated with CAR bacillus isolates known to contain M. pulmonis, whereas single PCR gave no positive results. We conclude that nested PCR is superior to single PCR or culture for detecting M. pulmonis, and that M. pulmonis is present in all but four CAR bacillus isolates in our collection that were from naturally infected rats; the four isolates that were exceptions were obtained from rats from a single colony.

Animals↗