Faculty Bibliography

A rapid, simple, modified heat-stable acid phosphatase and 68 degrees C catalase test for the differentiation of mycobacteria is described. A total of 181 strains of mycobacteria, including 141 slow growers and 40 rapid growers, were investigated for acid phosphatase and catalase activities

An outbreak of Pasteurella multocida infection, involving seven patients on two adjacent wards, has been observed. All seven patients were debilitated and had underlying chronic neuromuscular and/or pulmonary disease and had a tracheostomy tube in situ. The isolates of P. multocida were of the same biotype and serotype, and had an identical antibiogram. Epidemiological studies failed to determine the source of these infections

There is presently no accepted method for marking individual strains of Staphylococcus epidermidis. Consequently, five parameters for distinguishing such strains were examined and compared for their epidemiological efficacy: biotyping, serotyping, proteinase grouping, aminopeptidase profiles and antibiograms. Both biotyping and proteinase grouping were of limited use in identifying a particular strain, although they were helpful in initially categorizing such strains. Antibiograms were least useful because of similarities in susceptibility patterns among isolates. Serotyping and amino-peptidase profiles provided the best means of identifying an individual strain for epidemiological use. The applicability of these typing methods was demonstrated during a one year epidemiological study at a chronic disease hospital

Three hundred sixty-five isolates of Staphylococcus epidermidis (coagulase-negative) obtained over a 12-month period from 10 selected wards at New York University Medical Center-Goldwater Memorial Hospital, Roosevelt Island, N.Y., were typed serologically by slide agglutination. The isolates were first biotyped by the Baird-Parker scheme and then subtyped as proteinase-positive or proteinase-negative so that the selection of strains for immunologic study was based on biochemical and enzymatic factors rather than on random choice. The biotyping scheme of Baird-Parker and the differentiation between proteolytic and nonproteolytic strains were of limited in initial categorization of isolates of S. epidermidis. Antisera to proteinase-positive and proteinase-negative S. epidermidis biotypes 1 and 4 were absorbed with different permutations of homologous and heterologous thermostable (TS) and thermolabile (TL) antigens, and four distinct TL and two distinct TS antigenic groups, representing five different serotype patterns (i.e., A1-2, B1-2, C-D1, C-D1-2, and E1), were detected. The TL antigens also appeared to be more widespread and were shared more frequently by strains of S. epidermidis than were TS antigens, but the use of both TS and TL antigens provided a better serologic system than use of either TS or TL antigens alone

The presently accepted method for marking individual strains of Staphylococcus aureus for epidemiological investigation is bacteriophage typing. However, phage typing is not a stable marker and many strains cannot be successfully typed. Serological typing is not readily available and preparation of sera is difficult. The aminopeptidase profile method described by Krawezyk and Huber was used to mark strains of S. aureus. Profiles were constructed diagramming the percent hydrolysis of 22 beta-naphthylamide substrates by 15 isolates of S. aureus. The aminopeptidase profiles (APP) were thought to be more complete in marking individual strains of S. aureus when compared to bacteriophage and serological typing. Thusly, this method has applicability in the clinical laboratory for epidemiological investigation of S. aureus

Seven different strains of Staphylococcus epidermidis and one strain of S. aureus were catagorized by their aminopeptidase activity. Eight different profiles were obtained: five profiles for S. epidermidis biotype 4 (each representing a different known serotype), two profiles for S. epidermidis biotype 1 (one for each strain used) and one for the strain of S. aureus used. Despite some similarities, distinct patterns of the hydrolysis of 22 different amino acid-beta-naphthylamides were evident for each individual strain. The evaluation of aminopeptidase profiles provides another means for distinguishing between strains of the same species and can, therefore, be used advantageously and in combination with serotyping as an epidemiological tool

Electrophoretic and serologic characterization of extracellular proteinases from 111 isolates (80 biotype 1 and 31 biotype 4) of Staphylococcus epidermidis (coagulase negative) of human origin were conducted. Seventy-seven (60 of biotype 1, 17 of biotype 4) of the 111 proteinase-positive isolated of S. epidermidis were classified by serological differentiation of their proteolytic enzymes with known specific antisera. Thirty-two (18 of biotype 1, 14 of biotype 4 (isolates of S. epidermidis produced proteolytic enzymes that did not react with any of the known group antisera and were classified as NR (non-reacting). No classification of the enzymes of two other isolates was possible. The NR proteinase enzymes from the 32 cultures that could not be classified by serological differentiation with the known specific antisera fitted into one of three electrophoretic mobility patterns: NR1, NR2 or NR3. Seventy-eight isolates of S. epidermidis biotype 1 were placed into four proteinase sero-groups; 49 in F, 11 in B, 11 in NR2, and 7 in NR3. Thirty-one isolates of S. epidermidis biotype 4 were placed into one of two groups: 17 in C and 14 in NR. All enzymes tested migrated towards the anode at pH 8.6, and the order of electrophoretic mobility was NR3 greater than F greater than NR2 greater than NR1 greater than B greater than C

The germ tube test is routinely used for the rapid identification of Candida albicans and its variant C. stellatoidea, and is generally thought to be specific for these organisms. Four cases in which yeastlike fungi were isolated, and, although they were germ tube-positive, further morphologic and biochemical examinations identified them as Candida tropicalis are presented