Central venous catheter infection caused by Moraxella osloensis in a patient receiving home parenteral nutrition.

We report the first case of a central venous catheter infection caused by Moraxella osloensis, which was successfully treated without catheter removal. The isolation, identification, and pathogenesis of this species are discussed. It is recommended that Moraxella isolates be identified to species in order to determine the relative pathogenic and opportunistic roles of the various Moraxella species. Our case also demonstrates that catheter sepsis caused by some Gram-negative organisms may be amenable to systemic antibiotic therapy without the necessity of catheter removal.

Moraxella atlantae bacteraemia in a patient with systemic lupus erythematosis.

We describe the first reported case of human infection caused by Moraxella atlantae (formerly known as CDC group M-3) and its successful treatment with intravenous cefuroxime. The isolation and identification of this species, as well as the pathogenesis of the infection, are discussed. It is recommended that isolates of Moraxella species be speciated so that the epidemiological characteristics and pathogenesis of the infections caused by the various species may be understood more completely.

Methods for identification of flavobacteria.

Published reports disagree on the best features for detecting and distinguishing between Flavobacterium meningosepticum (biovar IIa) and Flavobacterium species CDC group IIb (biovar IIb; Flavobacterium indologenes). This report discloses that at least some of these disagreements may reflect the methods used. To detect production of indole, a modified Kovács reagent (not Ehrlich) and a buffered tryptophan medium were optimal, but not all strains of these two biovars produced indole. To distinguish the two biovars, hydrolysis of corn starch was preferable to that of soluble potato starch. Both biovars may hydrolyze DNA; the differentiation achieved varied with the methods used. Both biovars presented pigmented growth; only IIb, however, was obviously pigmented on a 2-day blood agar plate. Acidification of D-arabinose definitively distinguished these two biovars; several additional features were useful but not definitive.

Identification of oxidase-positive, glucose-negative, motile species of nonfermentative bacilli.

Motile and glucose-negative nonfermentative bacilli are difficult to identify by commonly used procedures. We found eight features (reduction of nitrate and nitrite, acidification of fructose, and alkalinization of acetamide, arginine, histidine, saccharate, and urea) that identified 83% of 143 strains. These, along with additional biochemical tests, effected identification of 93% of the strains. Hence, only a minority of these strains required examination by microscopy (for type of flagellation and presence of inclusion bodies) for complete identification.

Salient features of Haemophilus vaginalis.

A total of 78 strains of Haemophilus vaginalis were examined for 104 features. All strains fermented dextrin, maltose, and starch. Additionally, more than 90% of the strains fermented galactose, glucose, and ribose. Arbutin, cellobiose, melibiose, rhamnose, and salicin were not fermented by any of these strains. None of the strains acidified any of 14 alcohols or alkalinized any of 25 organic salts and amides. More than 90% of the strains hemolyzed human blood agar and hydrolyzed hippurate. No strain hemolyzed sheep blood agar. A recommendation is included for those minimal features that best differentiate H. vaginalis from other oxidase- and catalase-negative, gram-negative organisms.

A study of the Va-1 group of pseudomonads and its relationship to Pseudomonas pickettii.

The Va-1 group of denitrifying pseudomonads was characterized and compared with Pseudomonas pickettii (Va-2). They share many features but differ in their production of acid from cellobiose, lactose and maltose and in their denitrification (gas from nitrate) at 35 degrees C. DNA-DNA hybridizations between a strain of Va-1 and the type strain of P. pickettii disclosed 84% homology and hence indicated that Va-1 is a biovar of this species. Since both are potential human pathogens, features are presented that distinguish these and other phenotypically similar species that are recovered from clinical specimens.

Delayed lactose fermentation by enterobacteriaceae.

Goodman, R. E. (University of California, Los Angeles), and M. J. Pickett. Delayed lactose fermentation by Enterobacteriaceae. J. Bacteriol. 92:318-327. 1966.-When 171 Citrobacter freundii strains and 14 Paracolobactrum arizonae strains examined, 51 of the C. freundii strains and 13 of the P. arizonae strains were found to be delayed or negative lactose fermenters. Of the slow fermenters, 65% yielded rapidly fermenting mutants in cultures undergoing delayed fermentation. Lactose fermentation could generally be hastened by increasing lactose concentrations. Many organisms which fermented lactose slowly grew readily on a medium containing lactose as the sole carbon source. Regardless of their ability to ferment lactose, all strains of C. freundii and P. arizonae investigated could be shown to possess beta-galactosidase. Delayed fermenters failed to take up lactose from the culture medium, whereas prompt fermenters did so readily. The beta-galactosidases of 12 strains of enteric bacteria were studied in crude cell extracts with respect to specific activity, stability, and activity at varying substrate (o-nitrophenyl-beta-d-galactopyranoside) concentrations, at varying pH, and in the presence of sodium, potassium, and magnesium. The widely varying specific activities and the approximate similarity of the Michaelis constants (about 2 x 10(-4)m) suggested that the strains investigated produced differing amounts of beta-galactosidase. Moreover, qualitative differences in the enzymes provided evidence that these strains synthesized different molecular forms of beta-galactosidase. The results suggested that organisms which ferment lactose only after a prolonged delay do so because they possess multiple defects in their lactose-metabolizing machinery.

Characterization of bacteria by their degradation of amino acids.

A procedure for detecting the degradation of amino acids by microorganisms is described, and examples of its use in the characterization of bacteria are presented. The procedure involves inoculating a buffered solution of amino acids with a suspension of bacteria, incubating, chromatographing a sample of the suspension, and detecting degradation in terms of absence of ninhydrin-positive spots.

Beta-galactosidase for distinguishing between Citrobacter and Salmonella.

Detection of beta-galactosidase with the aid of o-nitrophenyl-beta-d-galactopyranoside (ONPG) was examined as a means for distinguishing between Citrobacter and Salmonella. Several factors which influence sensitivity and reliability of the test were studied. A bacteriostat, sodium azide, was included to permit prolonged incubation of weak and negative strains of enteric bacilli. By the procedure described, salmonellae gave negative ONPG tests; all of 171 strains of Citrobacter gave positive tests.

Deoxyribonuclease: detection with a three-hour test.

A three-hour test has been developed to determine deoxyribonuclease activity of Enterobacteriaceae and staphylococci. The test is inexpensive and easy to perform. The rapid deoxyribonuclease test and the conventional method showed complete agreement with the strains tested.

Reaction of Vibrio cholerae and choleragenic toxin in ileal loop of laboratory animals.

Accumulation of fluid in the ligated ileal loop upon injection of cholera vibrios or choleragenic toxin seems to be a generalized phenomenon in laboratory animals.

Rapid method for identification of gram-negative, nonfermentative bacilli.

A rapid system (OA), based on oxidative attack of substrates, was developed for identification of gram-negative, nonfermentative bacillia (NFB). One hundred and twelve strains of NFB from 25 species (representing the genera Pseudomonas, Alcaligenes, Acinetobacter, Bordetella, Flavobacterium, Moraxella, and Xanthomonas) were assayed by OA, buffered single substrate, and oxidative/fermentative methods. The 38 substrates consisted of salts of organic acids, nitrogen-containing compounds, alcohols, and carbohydrates. Ninety-four percent of the test strains were identified by the OA method in 24 h, and 99% were identifiable in 48 h. Reproducibility was 99%. Correlation with buffered single substrate was 98% (all substrates) and 90% with the oxidative/fermentative method (carbohydrates only). Biochemical profiles of all strains are presented, as well as tables showing the most useful tests for identification.

Tests for detecting degradation of gelatin: comparison of five methods.

Five methods for detecting degradation of gelatin by bacteria were compared. These were liquefaction in nutrient broth, hydrolysis in nutrient agar, hydrolysis of charcoal gelatin strips, degradation of the gelatin on strips of photographic film, and alkalinization of gelatin agar. Degradation of photographic film is a rapid and convenient method but, like hydrolysis of gelatin in broth and in agar, may fail to detect weakly positive strains of bacteria. Alkalinization of gelatin in an agar medium is a convenient and sensitive method to detect degradation of gelatin, particularly by Pseudomonas fluorescens, but this method may not be applicable to some species.

Methods for distinguishing gram-positive from gram-negative bacteria.

Lysis by KOH and hydrolysis of L-alanine-4-nitroanilide were compared with the Gram reaction of aerobic, microaerophilic, and anaerobic bacteria. Both tests correlated well with the Gram reaction with nonfermentative bacilli and Bacillus species, whereas they did not correlate with nonsporulating anaerobes. Only campylobacteria were KOH positive and L-alanine-4-nitroanilide and gram negative.

Antigens of mycobacterial cell walls.

Three antigenic fractions from the cell walls of eight strains of mycobacteria were studied. Isolation and purification of these antigens were effected by enzymatic digestions, differential and sucrose gradient centrifugations, dialyses, and column chromatography. Two of the fractions were termed cell wall tuberculins (CWT-1, solubilized with lipase; CWT-2, solubilized with lysozyme); the third was termed "C" (cross-reacting) antigen. All appeared to be lipopolysaccharides. The CWT antigens, as compared with purified protein derivatives (human), were relatively species (group)-specific in both double immunodiffusion and guinea pig skin tests; in the latter, the reactions resembled those of delayed hypersensitivity. The C antigens reacted heterologously in double immunodiffusion and skin tests; the latter were the "immediate" type of reaction.

Radiobacteriolysis: a new technique using chromium-51 for assaying anti-Vibrio cholerae antibodies.

A new method for detecting and quantitating antibodies against Vibrio cholerae is described. The reaction involves the release of radiochromium from prelabeled vibrios in the presence of specific antibody and complement. The entire assay can be completed within 5 hr. The method is highly reproducible, immunologically specific, temperature- and complement-dependent, and significantly more sensitive than other methods currently used for titration of anti-Vibrio cholerae antibodies. The technique is also potentially applicable to titration of antibodies against other gram-negative bacteria.