Indole-Spot test in Bacteriology

Vracko, Rudolf; Sherris, John C.

doi:10.1093/ajcp/39.4_ts.429

Cited by 65 publications

(19 citation statements)

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“…Biochemical and phenotypic analyses of H. influenzae and H. haemolyticus traits were performed as previously described by Kilian (25,26). Briefly, the emission of H 2 S was assessed with lead acetate strips (Fisher Scien- (26,25,39,60). Briefly, indole production was assessed by placing a small amount of bacteria on filter paper saturated with Kovács reagent (Remel) and observing the paper for a purple color reaction; urease activity was assessed in rapid urea broth (BD), according to the manufacturer's instructions, by mixing an inoculum loop of bacteria from the plate growth and observing the plate for a color reaction after 4 h of incubation at 37°C; and ODC activity was determined with ODC broth (Remel), according to the manufacturer's instructions.…”

Section: Methodsmentioning

confidence: 99%

Relationships of Nontypeable Haemophilus influenzae Strains to Hemolytic and Nonhemolytic Haemophilus haemolyticus Strains

et al. 2008

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Haemophilus influenzae is both a human respiratory pathogen and pharyngeal commensal, while H. haemolyticus, the closest phylogenetic relative of H. influenzae, is arguably a strict pharyngeal commensal. A hemolytic phenotype has historically differentiated H. haemolyticus from H. influenzae, but the recent recognition of significant nonhemolytic H. haemolyticus colonization has decreased this trait's resolvability. Given this and the potential of recombination between the species, we examined the distribution of microbiologic and molecular traits between collections of H. influenzae and H. haemolyticus strains separated within a dendrogram obtained by multilocus sequence analysis (MLSA). All strains hybridizing with a probe to iga, a gene encoding an immunoglobulin A protease of H. influenzae, clustered apart from strains that did not hybridize with the probe. Other traits also segregated significantly along this division, suggesting a separation of the species. Of note, the LOS genes licA, lic2A, and lgtC of H. influenzae were approximately 2, 6, and 54 times, respectively, more prevalent in H. influenzae than in H. haemolyticus. In contrast to species separation, interspecies recombination was evidenced by the inability of single gene sequences to phylogenetically separate the species and by the "fuzzy" distribution of some species-specific traits across the species dividing line. Together, these data support the historically accurate and pragmatic division of these species while recognizing their potential for recombination. Future comparative genomic studies identifying common and distinctive genes could be useful in evaluating their role in the commensal or virulent growth, respectively, of H. influenzae.Haemophilus influenzae is one of eight Haemophilus species that reside as commensal organisms in the pharyngeal cavity of humans. These other commensal Haemophilus species include H. parainfluenzae, H. haemolyticus, H. parahaemolyticus, H. paraphrohaemolyticus, H. segnis, H. aphrophilus, and H. paraphrophilus. H. influenzae is by far the most pathogenic member of the genus in humans. Strains possessing a type b capsule are often associated with invasive diseases, such as meningitis, sepsis, and pneumonia; and strains lacking a capsule (referred to as nontypeable [NT]) are associated with localized mucosal diseases, such as otitis media, sinusitis, and bronchitis. Other haemophili are considered to be rarely associated with disease, and H. haemolyticus has never been implicated as an infectious disease agent (1).In contrast to other haemophili, H. haemolyticus and H. influenzae both depend on X (hemin) and V (NAD) growth factors, both lack the ability to ferment sucrose, both share similar GϩC contents, and both are nearly indistinguishable by their colony and cellular morphologies (25). Initial phylogenetic studies performed by using DNA-DNA hybridization revealed that H. haemolyticus associated with H. influenzae in a cluster of the family Pasteurellaceae termed Haemophilus sensu stricto (6,41,47), and t...

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Section: Methodsmentioning

confidence: 99%

Relationships of Nontypeable Haemophilus influenzae Strains to Hemolytic and Nonhemolytic Haemophilus haemolyticus Strains

et al. 2008

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“…This effectively decreased the amount of tube medium that needed to be kept on hand and allowed results to be obtained within 8 h. In 1962, LeMinor and Hamida demonstrated that the test results for the enzyme ␤-galactosidase (-nitrophenyl-␤-D-galactopyranoside) could reliably be read at the end of only 1 h of incubation (56). By 1963, Vracko and Sherris had adapted the concept of using paper disks and strips to develop "spot" tests, beginning with the test for indole production (93). They obtained excellent correlation when they compared their results to the results from conventional Kovacs' tube tests.…”

Section: Historical Perspectivementioning

confidence: 99%

Manual and Automated Instrumentation for Identification ofEnterobacteriaceaeand Other Aerobic Gram-Negative Bacilli

O'Hara

2005

Clin Microbiol Rev

116

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Identification of gram-negative bacilli, both enteric and nonenteric, by conventional methods is not realistic for clinical microbiology laboratories performing routine cultures in today's world. The use of commercial kits, either manual or automated, to identify these organisms is a common practice. The advent of rapid or “spot” testing has eliminated the need for some commonly isolated organisms to be identified with the systems approach. Commercially available systems provide more in-depth identification to the species level as well as detect new and unusual strains. The answers obtained from these systems may not always be correct and must be interpreted with caution. The patient demographics, laboratory workload and work flow, and technologist's skill levels should dictate the system of choice. Cost considerations introduce another variable into the equation affecting choice. Each system has its own strengths and weaknesses, and each laboratory must decide on the level of sophistication that fulfills its particular needs

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“…For this different indole reagents were tested. Five per cent p-dimethylaminobenzaldehyde in N-HC~ described by Vracko & Sherris (1963) was found to be the reagent best suited for detecting indole produced by colonies on cellulose membranes.…”

Section: Reagentsmentioning

confidence: 99%

A Rapid and Direct Plate Method for Enumerating Escherichia coli biotype I in Food

Anderson

Baird‐Parker

1975

Journal of Applied Bacteriology

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Direct enumeration of Escherichia coli biotype 1 in foods within 24 h has been achieved by a development of the method of Delaney, McCarthy & Grasso (1962) which is based on the production of indole at 44°. Indole positive E. coli growing at this temperature on a cellulose acetate membrane overlaying tryptone bile agar can be demonstrated. Characterization of 555 indole positive colonies from 843 samples of food showed that 95% were E. coli biotype 1 and a further 3·4% were ‘faecal coliforms’. Anaerogenic and non‐lactose fermenting E. coli are detected and the significance of these strains is discussed.

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Indole-Spot test in Bacteriology

Cited by 65 publications

References 0 publications

Relationships of Nontypeable Haemophilus influenzae Strains to Hemolytic and Nonhemolytic Haemophilus haemolyticus Strains

Relationships of Nontypeable Haemophilus influenzae Strains to Hemolytic and Nonhemolytic Haemophilus haemolyticus Strains

Manual and Automated Instrumentation for Identification ofEnterobacteriaceaeand Other Aerobic Gram-Negative Bacilli

A Rapid and Direct Plate Method for Enumerating Escherichia coli biotype I in Food

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