Aerobic Spore-forming Bacilli Research Articles

Surveillance of Microbiological Environment of Operation Theaters.

IntroductionControl of infections in the operation theater (OT) is of utmost importance. Microbiological surveillance is an effective tool for identifying and controlling infections. The purpose of this study was to investigate the prevalence rate of microorganisms in OTs, to identify the type of microorganisms, and to detect contamination of various surfaces and air of OT.MethodsOTs were properly cleaned with soap and water. All surfaces were disinfected, followed by fumigation with quaternary ammonium compounds. OTs were kept closed overnight. In the morning, they were opened, and samples were collected, taking all aseptic precautions. The settle plate method was used for air sampling, and the swab method was used for surface sampling. Samples were collected from four surfaces of OTs, i.e., floor, wall, table, and light, and samples of the OT air were also collected and immediately transported to the microbiology laboratory of the institution in sterile conditions.ResultA total of 1640 swab samples were taken from eight OTs, out of which 487 (29.7%) were found positive for bacterial growth. Most of them were non-pathological microorganisms such as aerobic spore-forming Bacilli and Micrococcus. Among various OTs, septic OT showed the highest bacterial growth (82 positive cultures out of 200). In the surface sampling of various OTs, aerobic spore-forming Bacilli (221/487) was the most common isolate, followed by coagulase-negative Staphylococci (74/487), and Micrococcus (67/487). General surgery, septic, and emergency OTs had maximum air bioload (97, 93, and 91 colony-forming unit (CFU)/M3, respectively).ConclusionIn surface sampling of OTs, it was found that septic OT and general surgery OT were most contaminated where the patient load was high. Among all the surfaces, OT walls and tables were most contaminated with pathogenic microorganisms. The average air bioload of all OTs was ranged between 79 and 97 CFU/M3.

Microbial Regulation of the Antagonistic Activity of Lactic Acid Bacteria Strains under the Influence of Transient Bacilli of the Bacillus Genus

Aim. To study the effect of metabolites and components of aerobic spore-forming bacilli cells (MCASB) of the Bacillus genus on the antagonistic activity of lactic acid bacteria. Methods. Lactic acid bacteria, sampled from rectal and oral swabs from calves, were used in the study. Strains of conditionally pathogenic Escherichia coli, 055k59 No. 3912, Staphylococcus aureus No. 906, Proteus mirabilis, No. 3177, obtained from the collection of the city sanitary-epidemiological inspection service, were used as test cultures. MCASB were prepared using autoclaved microbial mass of Bacillus subtilis production strain 44-p via treatment with lysozyme and ultra- sound. The antagonistic activity of lactic acid bacteria was determined by agar blocks method. Results. It was demonstrated that the addition of MCASB to the culture medium stimulates the antagonistic activity of lactic acid bacteria to pathogenic and conditionally pathogenic microorganisms of intestinal bacteria. The highest average stimulation index (2.56) of the antagonistic activity of lactic acid bacteria was found for E. coli 055k59 No. 3912. Conclusions. The results obtained may be used to improve the microbiological foundations of elaborating novel probiotic preparations.

Special Features of Gram-Positive Bacterial Eradication by Photosensitizers

Antibiotic resistance of pathogenic bacteria is a major concern and presents a special challenge for development of alternative antibacterial modalities. One of these alternative approaches is based on using the photodynamic therapy (PDT) for eradicating bacteria. Photosensitizer-induced PDT exhibits unique properties and demonstrates efficient microbe-killing effects. The efficient and irreversible antimicrobial effects of PDT are not dependent on the antibiotic susceptibility of the pathogenic bacteria to antibiotics. Gram-positive bacteria exhibit efficient binding of the photosensitizer to the bacterial barriers, leading to immediate photoinactivation of the bacteria. Photoinactivation of Gram-positive bacteria by various photosensitizers has become a high priority, since these bacteria are responsible for life-threatening infections in humans, especially in the elderly and in compromised hosts in whom they cause hospital-acquired infections. The present review concentrates on the photoinactivation of Staphylococi, Streptococci, Propionibacterium acnes, Deinococcus radiodurans, aerobic spore-forming Bacilli by various photosensitizers and by various methods described in numerous works and patents.

Microbiological analysis and safety evaluation of various canned foods in Addis Ababa.

The microbiological quality and safety of canned foods available to consumers on the market in Addis Ababa were evaluated and the fate of contaminating pathogens in the canned foods, when stored at ambient and refrigerator temperatures, was also assessed. A total of 100 samples of canned foods comprising 20 each of fish, meat, vegetables, milk and soups were collected from Addis Ababa super markets and grocer’s shops. The aerobic mesophilic bacteria were dominated by Bacillus spp., Micrococcus spp. and other Gram positive rods. Staphylococci were encountered in some fish and meat canned food products. Salmonella and Shigella spp. were not detected in any of the 100 samples. A total of 250 aerobic spore-forming bacilli were isolated from canned foods. B. cereus, B. firmus , and B. licheniformis were the most frequent isolates. Antibiotic susceptibility studies showed that over 88% of Bacillus isolates were sensitive to chloramphenicol, erythromycin, gentamycin and kanamycin. Most isolates exhibited resistance to amoxicillin and ampicillin. Multiple antibiotic resistance (resistance to two or more drugs) was seen in 139 (53%) isolates. The most widespread pattern was Amo, Amp, Cep, Met, PenG, Sxt, Tet. In a challenge study, both Shigella flexineri and Salmonella thyphimurium grew and multiplied luxuriously in canned meat, fish, vegetable and soup at refrigeration and ambient temperatures. Keywords/phrases: Antimicrobial susceptibility, Bacillus spp., Canned foods, Microflora Ethiop. J. Biol. Sci ., 8(1): 53-69, 2009

Prevalence of Bacillus spp. in different food products collected in Argentina

The prevalence of Bacillus spp. in 279 samples of different food products collected in Argentina was studied. Bacillus spp. was confirmed in 28 out of 70 honey samples, 29 out of 29 flour samples, 15 out of 50 cheese samples, and 30 out of 30 spice samples, while Bacillus spp. was not found in fresh anchovy. Among the 70 honeys studied, Bacillus cereus, Bacillus pumilus, Bacillus laterosporus and Paenibacillus larvae subspp. larvae showed an incidence of 23%, 4%, 8% and 38%, respectively. More diversity of Bacillus species was found in rye flours than in white flours, Bacillus subtilis being the predominant species isolated from rye flour. B. cereus had an incidence of 50% in Port Salut Argentino cheeses. Meanwhile, B. pumilus was identified in both Port Salut and Quartirolo cheeses with an incidence of 50% and 25%, respectively. All the spices analysed showed Bacillus mycoides as the sole aerobic spore-forming bacilli isolated. The association of the presence of B. cereus, B. subtilis and Bacillus licheniformis with both the potential spoilage of foods and foodborne outbreaks is well known. In this study, Bacillus spp. had an incidence of 38% among all the samples analysed, therefore the monitoring of those species should be routinely done in microbiological food analyses.

Toxicity of Bacillus thuringiensis and B. sphaericus to laboratory populations of Drosophila melanogaster (Diptera: Drosophilidae).

A total of 65 samples, consisting of 8 sample types, collected from the Jordan Valley, were examined for the presence of Bacillus thuringiensis and B. sphaericus and for their toxicity against the larvae of the fruit fly Drosophila melanogaster. The frequency of samples containing toxic aerobic spore-forming bacilli was 12%; of which 21.7% belonged to B. thuringiensis and 17.4% to B. sphaericus. The B. thuringiensis populations consisted of 5 serogroups: thuringiensis (H1), entomocidus (H6), pakistani (H13), autoagglunated, in addition to a new serotype. The B. sphaericus population consisted of 3 serogroups, and belonged to serovars H5, H9, and H13. All B. thuringiensis and B. sphaericus local isolates, in addition to the reference strains B. thuringiensis kuristaki, and B. thuringiensis israelensis, showed high toxicity towards 3(rd) instar larvae of D. melanogaster. The toxic concentrations ranged between 2.0 x 10(6) and 4.4 x 10(7) viable spores ml(-1).

A limited number of Bacillus subtilis strains carry a tetracycline-resistance determinant at a site close to the origin of replication

Several strains of Bacillus subtilis, e.g., 168 derivatives and R, were found to carry a single copy of a tetracycline-resistance (Tc R) determinant (named tetBS908) at a site close to the origin of replication on the chromosome. This gene is highly homologous (80% identical) to the Tc R) determinant of plasmids widely dispersed among aerobic spore-forming bacilli. B. subtilis RM125 (168 strain) transformants which carry a varying number of tetBS908 sequences in a tandem array on the chromosome were constructed and examined for their Tc R level. A nearly proportional relationship between the Tc R level and copy number of tetBS908 existed.

A procedure for estimating Bacillus cereus spores in soil and stream-sediment samples — A potential exploration technique

The presence of bacterial spores of the Bacillus cereus group in soils and stream sediments appears to be a sensitive indicator of several types of concealed mineral deposits, including vein-type gold deposits. The B. cereus assay is rapid, inexpensive, and inherently reproducible. The test, currently under investigation for its potential in mineral exploration, is recommended for use on a research basis.Among the aerobic spore-forming bacilli, only B. cereus and closely related strains produce an opaque zone in egg-yolk emulsion agar. This characteristic, also known as the Nagler of lecitho-vitellin reaction, has long been used to rapidly indentify and estimate presumptive B. cereus. The test is here adapted to permit rapid estimation of B. cereus spores in soil and stream-sediment samples. Relative standard deviation was 10.3% on counts obtained from two 40-replicate pour-plate determinations. As many as 40 samples per day can be processed. Enough procedural detail is included to permit investigation of the test in conventional geochemical laboratories using standard microbiological safety precautions.

Closely related plasmids from Staphylococcus aureus and soil bacilli

Antibiotic resistance plasmids from staphylococci and soil bacilli have been isolated and compared. A tetracycline resistance (Tc r) plasmid, indistinguishable from pT181, which is typical of Tc r plasmids that are widely dispersed among human clinical isolates of S. aureus, has been found also in bovine mastitis isolates. This plasmid, however, shows no detectable homology to a family of related Tc r plasmids, typified by pBC16, that is widely dispersed among aerobic spore-forming bacilli. However, and rather unexpectedly, pBC16 is highly homologous to and incompatible with pUB110, an S. aureus plasmid specifying kanamycin resistance. The two plasmids are homologous except for the region occupied by their resistance determinants, which has the appearance of a heterologous substitution. These results suggest the occurrence of natural plasmid transfer between staphylococci and soil bacilli.

Studies on Phosphate-Solubilizing Bacteria in Soil and Rhizosphere of Different Plants: III. Inoculation with Phosphate-Dissolving Micro-organisms

Three different types of the most efficient phosphate-dissolvers were separately used for inoculating either wheat grains or broad-bean seeds. The selected micro-organisms were: aerobic spore-forming bacilli, non-sporeforming micrococci, and mycelial formers (actinomycetes). Both sterile and non-sterile soils as well as control pots (without seed inoculation) were used for growing the two plants (for 40 days) to find the effect of inoculation on plant growth, phosphorus percentage in the plants and uptake of phosphorus. Inoculated wheat grains and broad-bean seeds with the different types of phosphate-dissolvers resulted in increased uptake of phosphorus as well as in phosphorus content of the plants, grown either under sterile or non-sterile conditions. Generally, however, both plants contained greater quantities of phosphorus when grown in the presence of normal soil microflora (non-sterilized soil) than in their absence. This may demonstrate the influence of natural microbial flora on the availability of phosphorus to the growing plants. The results also suggest that the individual phosphate-dissolvers are not equally effective when inoculated on different plants. The mycelial-formers were significantly superior to the other two micro-organisms with respect to their effect on P-uptake by wheat grown in sterile soil. In non-sterile soil, the aerobic sporeformer inoculant was superior in case of wheat and inferior to the other two organisms in case of broad-bean. Weizen- und Pferdebohnensaatgut wurde mit einzelnen Gruppen phosphatlösender Mikroben (aerobe Bazillen, Mikrokokken und Aktinomyzeten) beimpft und in sterilen oder nicht sterilen Boden ausgesät. In allen Fällen haben die beimpften Pflanzen mehr Phosphor aufgenommen als die Kontrollpflanzen. Aber auch die natürliche Bodenmikroflora erhöhte die Phosphoraufnahme im Vergleich zur sterilen Kontrolle. Einzelne Mikrobengruppen waren unterschiedlich wirksam in Abhängigkeit von der Bodenmikroflora und der Art der Pflanze.

Beta-Galactosidase from Bacillus stearothermophilus.

Several strains of thermophilic aerobic spore-forming bacilli synthesize beta-galactosidase (EC 3.2.1.23) constitutively. The constitutivity is apparently not the result of a temperature-sensitive repressor. The beta-galactosidase from one strain, investigated in cell-free extracts, has a pH optimum between 6.0 and 6.4 and a very sharp pH dependence on the acid side of its optimum. The optimum temperature for this enzyme is 65 degrees C and the Arrhenius activation energy is about 24 kcal/mol below 47 degrees C and 16 kcal/mol above that temperature. At 55 degrees C the Km is 0.11 M for lactose and 9.8 X 10(-3) M for 9-nitrophenyl-beta-D-galactopyranoside. The enzyme is strongly product-inhibited by galactose (Ki equals 2.5 X 10(-3) M). It is relatively stable at 50 degrees C, losing only half of its activity after 20 days at this temperature. At 60 degrees C more than 60% of the activity is lost in 10 min. However, the enzyme is protected somewhat against thermal inactivation by protein, and in the presence of 4 mg/ml of bovine serum albumin the enzyme is only 18% inactivated in 10 min at 60 degrees C. Its molecular weight, estimated by disc gel electrophoresis, is 215 000.

Meningitis and bacteremia after ventriculoatrial shunt-revision: isolation of a lecithinase-producing Bacillus cereus.

patient developed neurologic abnormalities, cultures of cerebrospinal fluid and blood were reported growing B. subtilis. Some time ago, it was reported [3] that though presently unproven, . . . cases of infection in human beings involving aerobic spore-forming bacilli, and commonly attributed to B. subtilis . . . may actually be instances of infection with B. cereus.'' Since then, diagnosis of Bacillus species

Enzymatic control of the metabolic activity of Pseudomonas aeruginosa grown in glucose or succinate media.

Abstract Pseudomonas aeruginosa ATCC 9027 lacks phosphofructokinase and therefore does not have a functional Embden-Meyerhof pathway. However, it possesses the enzyme complement to carry out gluconeogenesis through the reversal of the Embden-Meyerhof pathway reactions. Glucose did not repress the enzymes of the tricarboxylic acid cycle. The results show that the tricarboxylic acid cycle plays a significant role in the metabolism of succinate apart from its essential biosynthetic role. The significance of a unique control pattern of glucose-metabolizing enzymes in Pseudomonas aeruginosa as compared to that found in coliforms and aerobic spore-forming bacilli is discussed.

Acido-thermophilic Bacteria from Thermal Waters

Three strains of acido-thermophilic bacteria were isolated from hot-spring waters of Tohoku district in Japan. They were aerobic spore-forming bacilli and identified to belong to genus Bacillus. Their characteristics were as follows. They were acidophilic, and grew well in the pH range of between 2.3 and 5.0. Optimal growth conditions were 65°C for temperature and 3.5~4.0 for pH of media. Strains T-4 and T-17 required biotin as growth factor, but T-7 did not require any factors for its growth. These bacteria were different from Bacillus stearothermophilus or B. coagulans in their taxonomic properties.

Identification of microorganisms isolated from jet fuel systems.

Seventy-two samples from jet aircraft fuel systems were examined for microbial contamination. Ten contaminated samples yielded 43 microorganisms which were classified into nine genera of bacteria and three genera of fungi. The predominant types, comprising about 37% of the isolated cultures, were identified as Bacillus spp. The remaining cultures were distributed among 11 genera, each of which represented 2 to 9% of the total isolates. Four cultures could not be assigned to a genus on the basis of the diagnostic criteria used. Only five isolates, in the genera Pseudomonas and Hormodendrum (Cladosporium), grew abundantly in a mineral salts solution with JP-4 fuel as the sole source of carbon. The presence of fuel utilizers in a fuel system may be a better index to potential problems that have been correlated with microbial contamination than the presence of aerobic sporeforming bacilli.

Acido-thermophilic Bacteria from Thermal Waters

Three strains of acido-thermophilic bacteria were isolated from hot-spring waters of Tohoku district in Japan. They were aerobic spore-forming bacilli and identified to belong to genus Bacillus. Their characteristics were as follows. They were acidophilic, and grew well in the pH range of between 2.3 and 5.0. Optimal growth conditions were 65°C for temperature and 3.5~4.0 for pH of media. Strains T-4 and T-17 required biotin as growth factor, but T-7 did not require any factors for its growth. These bacteria were different from Bacillus stearothermophilus or B. coagulans in their taxonomic properties.

Identification of Microorganisms Isolated from Jet Fuel Systems

Seventy-two samples from jet aircraft fuel systems were examined for microbial contamination. Ten contaminated samples yielded 43 microorganisms which were classified into nine genera of bacteria and three genera of fungi. The predominant types, comprising about 37% of the isolated cultures, were identified as Bacillus spp. The remaining cultures were distributed among 11 genera, each of which represented 2 to 9% of the total isolates. Four cultures could not be assigned to a genus on the basis of the diagnostic criteria used. Only five isolates, in the genera Pseudomonas and Hormodendrum (Cladosporium), grew abundantly in a mineral salts solution with JP-4 fuel as the sole source of carbon. The presence of fuel utilizers in a fuel system may be a better index to potential problems that have been correlated with microbial contamination than the presence of aerobic sporeforming bacilli.

Differential media for the identification of Bacillus anthracis.

Knisely, Ralph F. (U.S. Army Biological Laboratories, Fort Detrick, Frederick, Md.). Differential media for the identification of Bacillus anthracis. J. Bacteriol. 90:1778-1783. 1965.-Two new differential media for the identification of Bacillus anthracis are described. Phenethyl alcohol and chloral hydrate were used as selective ingredients. These media should aid in the differentiation of B. anthracis from B. cereus and, if used in conjunction with other differential tests, they should also differentiate B. anthracis from the majority of other aerobic sporeforming bacilli. These media might also be useful in the classification of Bacillus species.

Aerobic sporeforming bacilli showing the phenomenon of colony migration

It is proposed that the grouping of unicellular forms of bacteria into clusters or colonies may be the first step in the evolution of multicellular forms and that any further evolutionary advance would require the subordination of the impulses of the individual in favour of the needs of the “colony”. This latter relationship is exemplified by the group movement of certain aerobic sporeforming bacilli. A description of the nature of this movement on the surface of nutrient agar has been made. Studies on 54 strains showing this group movement reveal that they taxonomically constitute a nebulous group in Morphological Group II of the genus Bacillus according to the presently accepted system of classification (Bergey's Manual 1957). While the large majority of the strains studied morphologically resemble B. alvei, none exhibit the typical physiological characteristics of this species. Considering all the characteristics studied, the strains in our collection could be placed in an indefinite group comprising B. alvei, B. circulans, B. laterosporus and B. pulvifaciens. This however does not reflect any marked dissimilarities between the strains studied but rather the unsatisfactory taxonomy of the species enumerated. A re-examination of the determinative classification of these four species especially with reference to the unsatisfactory use of starch hydrolysis in the key to the genus is suggested.

Egg-yolk reactions of Pseudomonas species.

VARIOUS bacteria are known, to produce opalescence in egg-yolk emulsions due to lecithinase or lipase activity. Among these are the lecithinase-producing clostridia and aerobic spore-forming bacilli, and the lipolytic clostridia and staphylococci. Little attention seems to have been paid to the effects produced by Gram-negative organisms growing on egg-yolk media. Felsenfeld1 showed that the opalescence produced by four strains of Vibrio comma and one strain of Vibrio el tor was due to lecithinase activity, and Crook2 made a passing reference to one strain of Pseudomonas pyocyanea (Ps. aeruginosa) which produced an opalescence on egg-yolk agar. Willis3 noted tho opalescence changes produced by four strains of Ps. pyocyanea.