Identification of Branhamella catarrhalis in 2.5 min with an indoxyl butyrate strip test

Selective Butyrate Esterase Probe for the Rapid Colorimetric and Fluorogenic Identification of Moraxella catarrhalis

Clinical identification of the pathogenic bacterium Moraxella catarrhalis in cultures relies on the detection of bacterial butyrate esterase (C4-esterase) using a coumarin-based fluorogenic substrate, 4-methylumbelliferyl butyrate. However, this classical probe may give false-positive responses because of its poor stability and lack of specificity. Here, we report a new colorimetric and fluorogenic probe design employing a meso-ester-substituted boron dipyrromethene (BODIPY) dye for the specific detection of C4-esterase activity expressed by M. catarrhalis. This new probe has resistance to nonspecific hydrolysis that is far superior to the classical probe and also selectively responds to esterase with rapid colorimetric and fluorescence signal changes and large "turn-on" ratios. The probe was successfully applied to the specific detection of M. catarrhalis with high sensitivity.

Evaluation of the BactiCard Neisseria for identification of pathogenic Neisseria species and Moraxella catarrhalis

The BactiCard Neisseria (Remel, USA) is a chromogenic enzyme substrate system for identifying Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria lactamica, and Moraxella catarrhalis. The identification system consists of a card with four test circles impregnated with chromogenic substrates for indoxyl butyrate esterase (IB), prolyl aminopeptidase (PRO), gamma-glutamyl aminopeptidase (GLUT), and ss-galactosidase (BGAL). These substrates permit the identification of Moraxella catarrhalis, Neisseria gonorrhoeae, Neisseria meningitidis, and Neisseria lactamica, respectively. After hydration of the circles with buffer, colonies from growth on selective media or a subculture are applied to the four circles. IB and BGAL reactions are read for a blue-green color after 2 and 15 min, respectively. PRO and GLUT reactions are read at 15 min for a red color after addition of a developer reagent. Identifications obtained with the BactiCard Neisseria were compared with those obtained using conventional procedures for 558 isolates in a blinded fashion. The BactiCard Neisseria identified 100% of 254 Neisseria gonorrhoeae, 100% of 125 Neisseria meningitidis, 53 (98.2%) of 54 Neisseria lactamica, and 123 (98.4%) of 125 Moraxella catarrhalis isolates. The BactiCard Neisseria is an accurate and rapid system for identification of these microorganisms in the clinical laboratory.

Rapid identification of bacteria and yeast: summary of a National Committee for Clinical Laboratory Standards proposed guideline

Using colony morphology on selected agars, Gram-stain morphology, and a number of 1-step biochemical or enzymatic tests, skilled microbiologists can identify the species of the majority of isolates seen routinely in a clinical laboratory. These results are often available more quickly than and are as accurate as those derived from conventional methods. The National Committee for Clinical Laboratory Standards has produced a guideline that describes tests that can be used to identify a number of aerobic gram-negative rods and gram-positive cocci, a number of commonly isolated anaerobes, and 3 species of yeast. An overview of the organisms included in the guideline, the tests that identify them, and the situations in which rapid testing is appropriate is presented here.

Comparison of three rapid methods, tributyrine, 4-methylumbelliferyl butyrate, and indoxyl acetate, for rapid identification of Moraxella catarrhalis

Moraxella catarrhalis can easily be differentiated from other oxidase-positive, gram-negative cocci with tributyrine, 4-methylumbelliferyl butyrate, or indoxyl acetate. All M. catarrhalis give positive reactions, and all Neisseria spp. give negative reactions. The 4-methylumbelliferyl butyrate tube test and indoxyl acetate strip test provide same-day identification of M. catarrhalis isolates.

Fluorogenic and chromogenic substrates used in bacterial diagnostics

Methods based on the application of chromogenic and fluorogenic substrates enable specific and rapid detection of a variety of bacterial enzymatic activities. By using these techniques, enzymatic reactions can be examined simultaneously or individually, either directly on the isolation plate or in cell suspensions. For this purpose, various testing principles and test kits for clinical and food microbiology have been introduced successfully during the last few years. In this paper we present a survey of different enzymes of microbial origin that are utilized for microbiological identification and differentiation and the corresponding methods. Particular emphasis is given to the examination of Escherichia coli and the description of the different techniques as used in routine analysis.

Butyrate esterase (4-methylumbelliferyl butyrate) spot test, a simple method for immediate identification of Moraxella (Branhamella) catarrhalis [corrected]

A total of 47 Moraxella (Branhamella) catarrhalis strains, 89 strains of Neisseria spp., and 82 strains of miscellaneous bacteria and yeasts were studied by using a fluorogenic spot method which detects butyrate esterase. A positive butyrate esterase spot test correctly differentiated M. catarrhalis from Neisseria spp., which had a negative butyrate esterase spot test reaction. The test is rapid, simple, and easy to perform. The butyrate esterase spot test was useful for direct identification of M. catarrhalis from primary cultures. However, false-positive reactions may occur with mixed cultures.

Branhamella catarrhalis: an organism gaining respect as a pathogen

Branhamella catarrhalis was formerly regarded as a common, essentially harmless inhabitant of the pharynx. This misapprehension was caused, in part, by confusion with another pharyngeal resident, Neisseria cinerea. The two organisms can now be differentiated by the positive reactions of B. catarrhalis in tests for nitrate reduction and hydrolysis of tributyrin and DNase. B. catarrhalis is currently recognized as the third most frequent cause of acute otitis media and acute sinusitis in young children. It often causes acute exacerbations of chronic bronchopulmonary disease in older or immunocompromised adults and is incriminated occasionally in meningitis, endocarditis, bacteremia, conjunctivitis, keratitis, and urogenital infections. Virulence-associated factors, such as pili, capsules, outer membrane vesicles, iron acquisition proteins, histamine-synthesizing ability, resistance to the bactericidal action of normal human serum, and binding to the C1q complement component, have been identified in some strains. beta-Lactamase producing strains, first detected in 1976, have risen to approximately 75% worldwide. Thus far, however, practically all American strains of B. catarrhalis remain susceptible to alternative antibiotics. A possible selective advantage of recent isolates is their reportedly heightened tendency for adherence to oropharyngeal cells from patients with chronic bronchopulmonary disease.

Evaluation of the indoxyl acetate hydrolysis test for rapid differentiation of Campylobacter, Helicobacter, and Wolinella species

A total of 410 well-defined Campylobacter, Helicobacter, and Wolinella strains, comprising 26 named species, subspecies, and defined groups, were tested for indoxyl acetate hydrolysis by a disk method by using disks prepared at the Centers for Disease Control, Atlanta, Ga. All C. coli (43 strains), C. cryaerophila (34 strains), C. fennelliae (5 strains), C. fennelliae-Campylobacter-like organism 3 (2 strains), C. jejuni (66 strains), C. jejuni subsp. doylei (3 strains), hippurate-negative C. jejuni-C. coli (15 strains), "C. upsaliensis" (39 strains), H. mustelae (5 strains), W. curva (1 strain), and W. recta (1 strain) hydrolyzed indoxyl acetate. Four strains gave weak positive reactions, and the remaining 196 strains, which belonged to 15 species, subspecies, and defined groups, gave negative reactions. Of the 410 study strains, 246 and 125 strains were tested for indoxyl acetate hydrolysis by a disk method and a tube method, respectively, by using commercially produced disks. The disk method, regardless of source, required less time and interpretation than the tube method did. Better differentiation between Campylobacter spp. was obtained with the indoxyl acetate test than with the trimethylamine N-oxide test. The indoxyl acetate disk distinguished C. lari from C. jejuni and C. coli, C. cinaedi from C. fennelliae, and H. pylori from H. mustelae and suggested that W. succinogenes could be differentiated from W. recta and W. curva. The indoxyl acetate disk method could be performed in 5 to 30 min, was easy to read and interpret, and should be useful as a routine diagnostic test for identification of Campylobacter spp.

Branhamella catarrhalis: phenotypic characteristics

PURPOSE

This review provides a comprehensive description and discussion of recognized phenotypic characteristics of Branhamella catarrhalis. An emphasis is placed on attributes of this organism that are relevant to its recovery and identification in the clinical microbiology laboratory. In addition, characteristics useful in determining strain identity for use in epidemiologic investigations are addressed. Finally, factors are discussed that may account for the infection-causing potential of B. catarrhalis or at least are of potential consequence to investigations of the pathogenesis of Branhamella disease.

CONCLUSIONS

B. catarrhalis is readily isolated from human clinical specimens and can be easily identified using simple, rapid laboratory techniques. Restriction endonuclease analysis of chromosomal deoxyribonucleic acid has proven to be a useful tool in epidemiologic studies. Beta-lactamase isoelectric focusing is of limited value because of the small number of distinct patterns. The lipopolysaccharide and outer membrane proteins of B. catarrhalis have been characterized and found to be relatively non-varying among different strains. Circumstantial evidence exists in support of the hypothesis that the B. catarrhalis beta-lactamase is a virulence determinant.