Glossy Colonies Research Articles

Physio-chemical properties of methyl red-degrading strains isolated from textile wastewater

Methyl red (MR)-reducing strains isolated from textile wastewater were identified and tested for physio-chemical properties. The bacterial colonies picked from the mineral medium supplemented with textile wastewater were transferred onto the mineral medium containing MR for the test. Two strains, namely SYK and STXL2, demonstrating the ability of MR decolorization in the agar medium were selected and purified. The strains SYK and STXL2 incubated in the liquid mineral medium with MR were able to reduce 100 % and 95.5 % of MR after 4 days incubation, respectively. Gram staining of both strains confirmed these two isolates were gram positive. The SYK strain has white, irregular and dry colonies while the STXL2 strain has orange, opaque, circular and glossy colonies. Both strains have short rod shape of cell under SEM images. The two strains were able to grow in the media such as Luria-Bertani medium, Meat-peptone broth, and Nutrient broth. The strain SYK were able to grow quickly in the medium with maltose while the strain STXL2 used glucose as the best carbon source. Biochemical tests showed that both strains had positive reaction in Voges-Proskauer test and negative reactions in lipase, cellulose, amylase, citrate, and gelatin hydrolysis tests. The SYK strain had positive reactions in protease, urease, and ammonia tests while the STXL2 strain had positive reaction in nitrate reduction test. The sequences of 16S rNA genes identified the SYK and STXL2 strains as Streptomyces cellulosae (100 % of similarity) and Rhodococcus ruber (99 % of similarity), and registered in the GenBank via the accessing number MZ414193 and MZ414194, respectively.

Major Insights into Microbiology: An Interview with Luciano Marraffini.

Major Insights into Microbiology: An Interview with Luciano Marraffini.

Canine Cystitis Caused by Salmonella enterica subsp. enterica

Background: Urinary tract infection in dogs is usually associated with the presence of bacteria, with a higher prevalence of Gram-negative bacteria, represented mainly by enteric bacteria such as Escherichia coli and Proteus spp., followed by Gram-positive bacteria such as Staphylococcus spp., and Streptococcus spp. There are scant reports of Salmonella spp. as the causative agent of urinary tract infection in dogs. Indeed, the literature describes only a few cases, most of which involve the isolation of these bacteria in feces. This paper reports a case of canine cystitis caused by Salmonella enterica subsp. enterica in the northeast region of Brazil.Case: A female dog of the Fila Brasileiro breed, about 9 year-old, wormed but unvaccinated, was evaluated at the Veterinary Hospital of the Federal University of Pernambuco – UFRPE. The dog showed clinical signs of apathy, cachexia, polyphagia, polyuria and opacity of the crystalline lens. The dog’s owner stated that the animal was fed with commercial dog food. In the clinical exam, the patient presented pale mucosa, cachexia, absence of ectoparasites, and her rectal temperature was 39.5°C. Moreover, cardiorespiratory auscultation of the patient revealed tachycardia (190 bpm) and tachypnea (36 bpm). The owner’s main complaint was the clinical condition of frequent urination (polyuria). A urinalysis and urine culture with antibiogram were requested as complementary exams, after collecting the urine by cystocentesis. The volume obtained in the physical examination of urinalysis was 7 mL of yellow urine with a putrid smell, cloudy appearance and density of 1.024. The chemical examination revealed pH 6.5, protein (+++), bilirubin (+), normal urobilinogen and negative reactions for glycoses, ketone, nitrite and urine occult blood. Bacteriuria and pyuria were detected in a urine sediment test. Urine was cultured on blood agar and Levine agar in a bacteriological incubator at 37°C under aerobiosis, for 24 h. This culture produced an exuberant and pure growth of glossy grey bacterial colonies on blood agar and glossy colonies on Levine agar. The Gram test revealed gram-negative bacilli. The sample was subjected to biochemical tests to identify Gram-negative enterobacteria, whose results provided a presumptive identification of Salmonella species. The microbial species was identified using a VITEK 2 Compact®, and was followed by a serology test for the identification of the serogroup using a polyvalent serum, which enabled the identification of Salmonella enterica subsp. enterica. The antibiogram showed sensitivity to ciprofloxacin, gentamicin and penicillin, and resistance to amoxicillin and ampicillin.Discussion: Clinical signs of cachexia and polyuria may be related to canine urinary tract infection caused by Salmonella enterica subsp. enterica, since these symptoms had already been recorded previously in a case of a bacterial infection by the same serogroup. Isolation of Salmonella spp. in a non-selective medium was determinant in identifying these bacteria. Since these are not commensal bacteria of the canine urinary tract, their isolation in this tract indicates that they are responsible for the infection or disease, although such cases are rare. Another aspect that should be highlighted is the risk of human infection, because of the zoonotic potential of Salmonella spp., which may be transmitted by contact with dog urine. This is the first report of the isolation of Salmonella enterica subsp. enterica in a case of canine cystitis on the northeast region of Brazil, and underscores the importance of complementary diagnostic exams such as urine culture.

Performance evaluation of oxacillin-resistant Staphylococcus aureus genotypes and taxa on human and animal blood agar culture media

The performance characteristics of growth, morphological aspects and hemolytic activities of oxacillin-resistant S. aureus (ORSA) strains were studied on twelve types of blood agar (BA) culture media (sheep, bovine, horse, rabbit and human). ORSA isolates were also previously characterized by isoenzymes genotyping and genetic and grouping analysis. Variations in the diameter of the colonies were detected among seven sets of BA media. In terms of morphology, 99, 53 and 98% presented shiny, yellow, and glossy colonies, respectively, regardless of the type of BAs. The rabbit BA favored the expression of hemolysins for most isolates (74%), followed by the human BA and other animal BAs. Certain BA media promoted the expression of hemolysins; however, the expression was correlated with a deficit in the colonial growth potential and vice-versa. The data point to the existence of two or more isolates genetically identical or highly related: (i) that either share or do not share the same wild species-specific phenotypes related to appearance without any influence from the external environment, and that are (ii) potentially virulent depending on the external environment. This study also suggestes the use of rabbit BA for the phenotypical characterization of S. aureus. Key words: Colonial morphology, hemolysis, human and animal blood agar, oxacillin-resistant Staphylococcus aureus, clinical microbiology.

Anaerocella delicata gen. nov., sp. nov., a strictly anaerobic bacterium in the phylum Bacteroidetes isolated from a methanogenic reactor of cattle farms

A strictly anaerobic bacterial strain (WN081(T)) was isolated from rice-straw residue in a methanogenic reactor treating waste from cattle farms in Japan. Cells were Gram-staining negative, non-motile, non-spore-forming straight rods. The strain grew rather well on PY agar slants supplemented with a B-vitamin mixture as well as sugars (PYV4S medium) and made translucent and glossy colonies. Growth in liquid medium with the same composition, however, was scanty, and growth was not improved in spite of various additives to the medium. Strain WN081(T) produced small amounts of acetate, propionate, isobutyrate, butyrate, isovalerate and H(2) from PYV liquid medium. The strain did not use carbohydrates or organic acids. The pH range for growth was narrow (pH 6.8-8.2), having a pH optimum at 6.8-7.5. The temperature range for growth was 10-37°C, the optimum being 25-30°C. The strain was sensitive to bile, and did not have catalase or oxidase activities. Hydrogen sulfide was produced from L-cysteine and L-methionine as well as peptone. Indole was produced from L-tryptophan and peptone. The strain had iso-C(15:0) as the exclusively predominant cellular fatty acid (70%) together with some branched chain components (such as iso-C(15:0) DMA, iso-C(17:0) 3-OH and iso-C(15:0) aldehyde) as minor components. The genomic DNA G+C content was 32.3 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence placed strain WN081(T) in the phylum Bacteroidetes with rather low sequence similarities with the related species such as Rikenella microfusus (85.7% sequence similarity), Alistipes putredinis (85.5%) and Alistipes finegoldii (85.5%) in the family Rikenellaceae. Based on the phylogenetic, physiological and chemotaxonomic analyses, the novel genus and species Anaerocella delicata gen. nov., sp. nov. is proposed to accommodate the strain. The type strain is WN081(T) (= JCM 17049(T) = DSM 23595(T)).

The Myxococcus xanthus lipopolysaccharide O‐antigen is required for social motility and multicellular development

The gliding bacterium Myxococcus xanthus aggregates to form spore-filled fruiting bodies when nutrients are limiting. Defective fruiting-body formation and sporulation result from mutations in the sasA locus, which encodes the wzm wzt wbgA (formerly rfbABC) lipopolysaccharide (LPS) O-antigen biosynthesis genes. Mutants carrying these same sasA mutations are defective in social motility and form small glossy colonies. We report here that the developmental and motility phenotypes of four mutants each containing different Tn5 insertions in LPS O-antigen biosynthesis genes are similar to those of the original sasA locus mutants. All of the LPS O-antigen mutants tested exhibited defective developmental aggregation and sporulated at only 0.02-15% of the wild-type level. In addition, all of the LPS O-antigen mutants were determined by genetic analyses to be wild type for adventurous motility and defective in social motility, indicating that the LPS O-antigen is necessary for normal development and social motility. The two previously identified cell-surface components required for social motility, type IV pili and the protein-associated polysaccharide material termed fibrils, were detected on the surfaces of all of the LPS O-antigen mutants. This indicates that LPS O-antigen is a third cell-surface component required for social motility.

A novel pathogenic taxon of the Mycobacterium tuberculosis complex, Canetti: characterization of an exceptional isolate from Africa.

In an attempt to characterize an unusual mycobacterial strain isolated from a 2-year-old Somali patient with lymphadenitis, we applied various molecular methods not previously used for the taxonomic classification of mycobacteria. This isolate, designated So93, did not differ from Mycobacterium tuberculosis in the biochemical tests and in its 16S rRNA sequence, but produced smooth and glossy colonies, which is highly exceptional for this species. This smooth phenotype was unstable and switched nonreversibly to a rough colony morphology with a low frequency. The two colony types were equally virulent for the guinea pig, exhibiting characteristic tuberculous disease. Both morphotypes had shorter generation times than the M. tuberculosis reference laboratory strain H37Rv and clinical isolates of M. tuberculosis and Mycobacterium bovis. Furthermore, the So93 isolate differed from all M. tuberculosis complex strains described thus far by having only a single copy of insertion sequence IS1081, an unusual composition of the direct repeat cluster, and a characteristic phenolic glycolipid and lipooligosaccharide. This glycolipid had previously been observed only in a smooth isolate of M. tuberculosis obtained in 1969 by Canetti in France. Analysis of the Canetti strain showed that it shared virtually all genetic properties characteristic of So93, distinguishing these two strains from the known M. tuberculosis complex taxa, M. tuberculosis, Mycobacterium africanum, M. bovis, and Mycobacterium microti. The natural reservoir, host range, and mode of transmission of the group of bacteria described in this paper are presently unknown. This study, partly based on not previously used molecular criteria, supports the idea that the established members within the M. tuberculosis complex and the newly described Canetti grouping should be regarded as a single species, which likely will be designated "M. tuberculosis".

Characteristics of Isolates of Pseudomonas Solanacearum From Heliconia.

Pseudomonas solanacearum was isolated from Heliconia showing bacterial wilt in field-grown and imported plants. These isolates were compared with indigenous isolates from Strelitzia, Synedrella, Alpinia, Alexandra palm, tomato and sapote. They were characterised biochemically into biovars and pathogenically into races. Biovar 3 isolates were pathogenic on tomato but not on diploid nor triploid bananas. Only the Heliconia isolates were pathogenic on Heliconia psittacorum. Biovar 1 isolates from Helionia were very virulent on diploid and triploid bananas and H. psittacorum but not on tomato resembling pathogenic race 2, the cause of Moko disease in banana. On Kelman’s tetrazolium medium, biovar 1 isolates grew slower than biovar 3 isolates with white, circular, glossy colonies with red pigmented centre and clear fluidal edge, resembling the SFR insect-transmitted type described from Central America. The distribution, pathogenicity and origin of the tested isolates suggest that biovar 1 strains are of exotic origin.

Zur Loloniemorphologie von Clostridium Perfringens Typ A

At least 4 different colony forms of Clostridium perfringens on the surface of yeast extract blood agar after overnight incubation were demonstrated. A: glossy colonies with entire margins, mostly surrounded by narrow zones of complete hemolysis and a much wider zone of incomplete hemolysis (colonies typical for C. perfringens (Fig. 1), B: dwarf colonies, similar to A, but very small (Fig. 2), C: rough colonies slightly raised with lobate margins (Fig. 3-4), D: flat colonies with irregular surface and filamentous margins (Fig. 5). Three strains out of 126 gave rise to glossy and rough colony forms (Fig. 6).

Flu, a metastable gene controlling surface properties of Escherichia coli.

flu, a gene of Escherichia coli K-12, was discovered and mapped between his and shiA. It is shown that flu is a metastable gene that changes frequently between the flu+ and flu states. flu+ variants give stable homogeneous suspensions, are piliated, and form glossy colonies. flu variants aggregate, fluff and sediment from suspensions, are nonpiliated, and form frizzy colonies. flu+ and flu variants can be isolated from most strains. Implications of these observations are discussed, and it is demonstrated that flu+ variants of strain P678-54 yield three times more minicells than flu variants.

The relative importance of the capsule and the M-antigen in determining colony form of group A streptococci.

Evidence is presented showing that the surface configuration of Group A streptococcal colonies depends largely on whether or not the cocci form a capsule. Strains which form capsules during growth on agar produce mucoid or matt colonies. Strains that do not form capsules during growth on agar produce glossy colonies. Whether or not M antigen is formed by the growing cocci appears to have no direct effect on surface configuration of the colony, although there is an indirect and partial association between M production and the mucoid-matt variant state and between M deficiency and the glossy variant state.

VARIANTS OF HEMOLYTIC STREPTOCOCCI; THEIR RELATION TO TYPE-SPECIFIC SUBSTANCE, VIRULENCE, AND TOXIN

Hemolytic streptococci, when freshly isolated from pathogenic lesions, form characteristic matt colonies and contain the type-specific substance M. Two varieties of matt cultures, equally rich in type-specific substance, can be distinguished by the virulence of the organisms for mice: (1) the matt virulent variety, (2) the matt attenuated variety. The matt forms of hemolytic streptococci can be degraded to a third variety which forms glossy colonies and is always relatively avirulent. This is accomplished by prolonged cultivation on artificial media, by selection of colonies or by cultivation in homologous anti-M serum. In the process of degradation the cocci lose the major part of their type-specific substance but complete disappearance of type-specific substance rarely occurs. The glossy variant form, when fully degraded, is highly stable; but glossy cultures which have retained some type-specific substance can occasionally be reverted to the original matt form. Toxic filtrates from matt and glossy cultures are approximately equal in skin reactivity. No relationship appears to exist between virulence and toxigenicity.