scholarly journals Evaluation of the API 20E system for identification of nonfermentative Gram-negative bacteria

1978 ◽  
Vol 7 (6) ◽  
pp. 539-545 ◽  
Author(s):  
M Shayegani ◽  
P S Maupin ◽  
D M McGlynn

The API 20E system for Enterobacteriaceae, recently broadened to include identification of nonfermentative gram-negative bacteria, was evaluated and compared with the conventional method for complete identification of 221 nonfermenters, which were well distributed into 48 species or biotypes and included organisms not listed in the API 20E data base. The results of 16 tests common to both systems were in close agreement. The API 20E system correctly identified 71 (43%) of the 165 organisms included in the API 20E data base. However, almost 90% of Acinetobacter calcoaceticus, three species of Pseudomonas, and Bordetella bronchiseptica were correctly identified to species.

1978 ◽  
Vol 7 (6) ◽  
pp. 533-538
Author(s):  
M Shayegani ◽  
A M Lee ◽  
D M McLynn

The Oxi/Ferm tube system designed for identification of oxidative-fermentative gram-negative bacteria was evaluated for identification of nonfermentative gram-negative bacilli by comparing it with the conventional system. The nine biochemical reactions used as the initial tests in the Oxi/Ferm tube system showed a close agreement with the same conventional reactions. However, the system was only 41% accurate to species or biotype for complete identification of 239 isolates which were well distributed in 48 species and biotypes and included organisms not listed in the Oxi/Ferm tube identification list. The system correctly identified 56% of the test organisms when the degree of identification was based on the manufacturer's guidance list. However, all isolates of Acinetobacter calcoaceticus, Bordetella bronchiseptica, Pseudomonas aeruginosa, P. diminuta, and group IIf were completely identified by the system.


Plant Disease ◽  
1998 ◽  
Vol 82 (3) ◽  
pp. 351-351 ◽  
Author(s):  
T. Isakeit ◽  
M. C. Black ◽  
J. B. Jones

Citronmelon fruits (Citrullus lanatus var. citroides (Bailey) Mansf.) with lesions were collected from a cowpea field in Frio County, TX, in July 1997. The lesions were circular, necrotic, or water-soaked, approximately 3 mm in diameter, and did not extend into the flesh of the fruit. Nonfluorescent, gram-negative bacteria were consistently isolated from lesions. Six representative strains were identified as Acidovorax avenae subsp. citrulli (Aac), using Biolog GN MicroPlates and the MicroLog data base release 3.50 (0.533 to 0.813 similarity). Aac causes leaf and fruit lesions (bacterial fruit blotch, BFB) on watermelon (C. lanatus (Thunb.) Matsum. & Nakai). Strains were tested for pathogenicity on watermelon seedlings (cv. Royal Sweet) by daubing bacterial suspensions (approximately 108 CFU/ml) onto cotyledons of 1-week-old seedlings. Water soaking of cotyledons, followed by necrosis and seedling death, occurred within 5 days. These symptoms were indistinguishable from those caused by watermelon strains of Aac. Bacteria were reisolated from symptomatic seedlings. The source of the infection is not known. Watermelons had been grown in this field in 1996, but no BFB symptoms were observed. Citron fruit infected with Aac were found in nearby watermelon fields where BFB was present; the closest field was 50 m from the cowpea field. These observations suggest that citronmelon, a common weed in south Texas, has the potential to perpetuate Aac. This is the first documentation of a naturally occurring infection of citronmelon with Aac.


mBio ◽  
2021 ◽  
Author(s):  
Richard M. Johnson ◽  
Zachary M. Nash ◽  
Margaret R. Dedloff ◽  
John C. Shook ◽  
Peggy A. Cotter

Two-partner secretion (TPS) systems are broadly distributed among Gram-negative bacteria and play important roles in bacterial pathogenesis. FhaB-FhaC is the prototypical member of the TPS family and we here identified the protease that initiates a processing cascade that controls FhaB function.


1998 ◽  
Vol 180 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Andrew G. Allen ◽  
Tomoko Isobe ◽  
Duncan J. Maskell

ABSTRACT A DNA locus from Bordetella pertussis capable of reconstituting lipopolysaccharide (LPS) O-antigen biosynthesis inSalmonella typhimurium SL3789 (rfaF511) has been isolated, by using selection with the antibiotic novobiocin. DNA within the locus encodes a protein with amino acid sequence similarity to heptosyltransferase II, encoded by waaF (previouslyrfaF) in other gram-negative bacteria. Mutation of this gene in B. pertussis, Bordetella parapertussis, and Bordetella bronchiseptica by allelic exchange generated bacteria with deep rough LPS phenotypes consistent with the proposed function of the gene as an inner core heptosyltransferase. These are the first LPS mutants generated in B. parapertussis andB. bronchiseptica and the first deep rough mutants of any of the bordetellae.


Author(s):  
Roger C. Wagner

Bacteria exhibit the ability to adhere to the apical surfaces of intestinal mucosal cells. These attachments either precede invasion of the intestinal wall by the bacteria with accompanying inflammation and degeneration of the mucosa or represent permanent anchoring sites where the bacteria never totally penetrate the mucosal cells.Endemic gram negative bacteria were found attached to the surface of mucosal cells lining the walls of crypts in the rat colon. The bacteria did not intrude deeper than 0.5 urn into the mucosal cells and no degenerative alterations were detectable in the mucosal lining.


Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.


Author(s):  
Xie Nianming ◽  
Ding Shaoqing ◽  
Wang Luping ◽  
Yuan Zenglin ◽  
Zhan Guolai ◽  
...  

Perhaps the data about periplasmic enzymes are obtained through biochemical methods but lack of morphological description. We have proved the existence of periplasmic bodies by electron microscope and described their ultrastructures. We hope this report may draw the attention of biochemists and mrophologists to collaborate on researches in periplasmic enzymes or periplasmic bodies with each other.One or more independent bodies may be seen in the periplasmic space between outer and inner membranes of Gram-negative bacteria, which we called periplasmic bodies. The periplasmic bodies have been found in seven species of bacteria at least, including the Pseudomonas aeroginosa. Shigella flexneri, Echerichia coli. Yersinia pestis, Campylobacter jejuni, Proteus mirabilis, Clostridium tetani. Vibrio cholerae and Brucella canis.


Author(s):  
Jacob S. Hanker ◽  
Dale N. Holdren ◽  
Kenneth L. Cohen ◽  
Beverly L. Giammara

Keratitis and conjunctivitis (infections of the cornea or conjunctiva) are ocular infections caused by various bacteria, fungi, viruses or parasites; bacteria, however, are usually prominent. Systemic conditions such as alcoholism, diabetes, debilitating disease, AIDS and immunosuppressive therapy can lead to increased susceptibility but trauma and contact lens use are very important factors. Gram-negative bacteria are most frequently cultured in these situations and Pseudomonas aeruginosa is most usually isolated from culture-positive ulcers of patients using contact lenses. Smears for staining can be obtained with a special swab or spatula and Gram staining frequently guides choice of a therapeutic rinse prior to the report of the culture results upon which specific antibiotic therapy is based. In some cases staining of the direct smear may be diagnostic in situations where the culture will not grow. In these cases different types of stains occasionally assist in guiding therapy.


Author(s):  
J Hanker ◽  
E.J. Burkes ◽  
G. Greco ◽  
R. Scruggs ◽  
B. Giammara

The mature neutrophil with a segmented nucleus (usually having 3 or 4 lobes) is generally considered to be the end-stage cell of the neutrophil series. It is usually found as such in the bone marrow and peripheral blood where it normally is the most abundant leukocyte. Neutrophils, however, must frequently leave the peripheral blood and migrate into areas of infection to combat microorganisms. It is in such areas that neutrophils were first observed to fragment to form platelet-size particles some of which have a nuclear lobe. These neutrophil pseudoplatelets (NPP) can readily be distinguished from true platelets because they stain for neutrophil myeloperoxidase. True platelets are not positive in this staining reaction because their peroxidase Is inhibited by glutaraldehyde. Neutrophil pseudoplatelets, as well as neutrophils budding to form NPP, could frequently be observed in peripheral blood or bone marrow samples of leukemia patients. They are much more prominent, however, in smears of inflammatory exudates that contain gram-negative bacteria and in gingival crevicular fluid samples from periodontal disease sites. In some of these samples macrophages ingesting, or which contained, pseudoplatelets could be observed. The myeloperoxidase in the ingested pseudoplatelets was frequently active. Despite these earlier observations we did not expect to find many NPP in subgingival plaque smears from diseased sites. They were first seen by light microscopy (Figs. 1, 3-5) in smears on coverslips stained with the PATS reaction, a variation of the PAS reaction which deposits silver for light and electron microscopy. After drying replicate PATS-stained coverslips with hexamethyldisilazane, they were sputter coated with gold and then examined by the SEI and BEI modes of scanning electron microscopy (Fig. 2). Unstained replicate coverslips were fixed, and stained for the demonstration of myeloperoxidase in budding neutrophils and NPP. Neutrophils, activated macrophages and spirochetes as well as other gram-negative bacteria were also prominent in the PATS stained samples. In replicate subgingival plaque smears stained with our procedure for granulocyte peroxidases only neutrophils, budding neutrophils or NPP were readily observed (Fig. 6).


Author(s):  
Rubal C Das ◽  
Rajib Banik ◽  
Robiul Hasan Bhuiyan ◽  
Md Golam Kabir

Macrophomina phaseolina is one of the pathogenic organisms of gummosis disease of orange tree (Citrus reticulata). The pathogen was identified from the observation of their colony size, shape, colour, mycelium, conidiophore, conidia, hyaline, spore, and appressoria in the PDA culture. The crude chloroform extracts from the organism showed antibacterial activity against a number of Gram positive and Gram-negative bacteria. The crude chloroform extract also showed promising antifungal activity against three species of the genus Aspergillus. The minimum inhibitory concentration (MIC) of the crude chloroform extract from M. phaseolina against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Shigella sonnie were 128 ?gm, 256 ?gm, 128 ?gm and 64 ?gm/ml respectively. The LD50 (lethal dose) values of the cytotoxicity assay over brine shrimp of the crude chloroform extract from M. phaseolina was found to be 51.79 ?gm/ml. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13378 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &2):125-133, 2010


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