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Biomedical subjects

R R Facklam

Publications and source records attributed to R R Facklam.

At least 145 records · Page 8Linked to original sources

Physiological characterization of nutritionally variant streptococci.

Twenty-five isolates of nutritionally variant streptococci submitted to the Streptococcus Laboratory of the Center for Disease Control over a 2-year period were tested for growth requirements and for biochemical reactions. After they were recovered from storage in blood at -170 degrees C, all isolates grew within 48 h in both thioglycollate broth and Todd-Hewitt broth supplemented with 0.001% pyridoxal.HCl. They grew better in the latter, even though they all grew on unsupplemented infusion agar, anaerobe blood agar, and chopped meat-glucose medium. Biochemical patterns of the isolates resemble those of five viridans streptococcal species. Two isolates had patterns which did not resemble those of any viridans species. Biochemical reactions obtained with heart infusion broth base biochemicals and carbohydrate fermentation media compared favorably for an overall agreement rate of 86.5% for key tests. Lactic acid and acetic acid were the major fermentation products detected with gas-liquid chromatography.

Acetates↗

Evaluation of commercial latex agglutination reagents for grouping streptococci.

A total of 155 strains of beta-hemolytic streptococci were serologically grouped by conventional techniques (Lancefield extraction and capillary precipitin testing) and by latex agglutination (LA). Agreement between conventional and LA techniques was 97% when the instructions of the manufacturer for the LA technique were followed. Agreement of 99% was obtained when modified autoclave extracts were used as antigens in the LA procedure. A total of 82 strains of non-beta-hemolytic streptococci were also tested by conventional, prescribed LA, and modified autoclave procedures. The agreement between conventional techniques and both LA procedures was 76%. However, when serological cross-reactions in the conventional grouping procedures were considered as errors, the accuracy of identification of both LA procedures was 88% among the non-beta-hemolytic strains. Of 13 strains of Streptococcus bovis, 10 did not react with the LA group D reagent but were serogroup D by conventional techniques. More S. bovis strains were grouped by the LA technique when extracts of 20 ml of broth cultures were used as antigens; however, cross-reactions were observed with non-group D strains when this technique was applied to them.

Hemolysis↗

Presumptive identification of group A, B, and D streptococci on agar plate media.

Several presumptive tests were evaluated for their effectiveness in differentiating streptococci. When the tests were combined into a battery and the resulting reactions were interpreted as patterns, the overall presumptive identification rate was at least 97%. We used the hemolytic reaction, susceptibility to bacitracin and sulfamethoxazole plus trimethoprim (1.25 micrograms plus 23.75 micrograms), and standard CAMP reactions on sheep blood Trypticase soy agar, and bile-esculin and 6.5% NaCl agar tolerance tests with incubation in candle extinction jars. Subsequently, 98.9% of the group A; 95.3% of the group B; 100% of the beta-hemolytic non-group A, B, or D; 92.3% of group D enterococcal; 100% of the group D non-enterococcal; and 92.8% of the viridans streptococci were presumptively identified. We then used the hemolytic reactions, susceptibility of bacitracin and sulfamethoxazole-plus-trimethoprim disks, CAMP disk reactions on sheep blood Trypticase soy agar and bile-esculin and 6.5% NaCl agar tolerance tests with incubation in normal atmosphere. Subsequently, 98.1% of the group A; 98.6% of the group B; 99.2% of the beta hemolytic non-group A, B, or D; 97.5% of the group D entercoccal; 97.6% of the group D non-entercoccal; and 92.4% of the viridans strains were presumptively identified.

Aerobiosis↗

Epidemiologic studies among Amerindian populations of Amazônia. I. Pyoderma: prevalence and associated pathogens.

Pyoderma was studied among a representative sample of the residents of four remote Amerindian villages, Amazonas State, Brazil, during July-August 1976. The overall prevalence among the 775 inhabitants examined was 11%, with little intervillage variation. When the attack rates for the entire sample population were calculated by 5-year age intervals, the 0- to 4-year-olds had the highest rate, 31%. The highest prevalence, 38%, was found among 3-year-olds. Attack rates were not apparently related to sex. Cultures which were taken from representative pyoderma lesions from people in the four survey villages and from three additional villages were studied by a modified delayed culture technique for recovery of gram-positive pathogens from silica-gel desiccated swabs. Group A and group G B-hemolytic streptococci, coagulase positive Staphylococcus aureus, and Corynebacterium diphtheriae were isolated. Group A S. pyogenes was most commonly found, occasionally as the sole pathogenic species. No nephritogenic M-types were found, although most isolates were not M-typable. The T-types found corresponded to those previously reported as being pyoderma-associated. Most pyoderma-associated C. diphtheriae isolates were non-toxigenic. Biotypes gravis and mitis were equally represented.

Adolescent↗

Wound infections due to group A streptococcus traced to a vaginal carrier.

An epidemic of surgical wound infections caused by group A Streptococcus affecting 18 patients in a community hospital was studied. Onset of symptoms shortly after surgery (median time, 16 hr) in 17 patients suggested acquisition of infection in the operating room, and a case-control investigation linked the presence during surgery of one particular nurse with postoperative streptococcal infection. During the first month of the epidemic, the nurse had streptococcal cellulitis of the finger and may thus have directly contaminated wounds or dressings. However, the last six wound infections occurred after her skin lesions had resolved and after nasopharyngeal and skin cultures were repeatedly negative for group A streptococci. Subsequent investigation showed that the nurse was colonized vaginally with group A streptococci of the same M and T types found in the infected patients and that this organism was disseminated into her immediate environment by airborne or droplet spread. Vaginal as well as rectal carriers of streptococci should be sought whenever outbreaks of streptococcal wound infection in which a cutaneous or nasopharyngeal carrier cannot be readily identified.

Carrier State↗

Antimicrobial susceptibility patterns of Streptococcus pneumoniae.

Fifty clinical isolates of Streptococcus pneumoniae received by the Streptococcus Laboratory of the Center for Disease Control from August 1976 through March 1977 and 50 pneumococcal strains retrieved from 13- to 16-year storage (originally isolated October 1961 through December 1964) were tested for susceptibility to 10 antimicrobial agents by disk-agar diffusion and agar dilution tests. No appreciable differences in susceptibility patterns were apparent between the two groups, and, except for one isolate, all were highly susceptible to every drug tested except gentamicin. This single isolate required higher drug concentrations to inhibit macroscopic growth and had corresponding decrements in zones of disk inhibition with penicillin, ampicillin, and cephalothin. An additional 43 pneumococci recently received from various areas of the United States and Canada were screened by a disk agar diffusion method for penicillin resistance. Four of these isolates had penicillin zone diameters <30 mm, and subsequent agar dilution test results showed that the penicillin minimum inhibitory concentrations were elevated with these organisms. Antimicrobial susceptibility patterns of pneumococci to antimicrobials other than penicillin and its analogs have not changed substantially in over a decade. However, due to the emergence of strains with decreased susceptibility to penicillin, the screening test for penicillin resistance in pneumococci, especially in isolates from spinal fluid and blood, could be clinically useful as an aid in selecting optimal therapy.

Cephalosporinase↗

Modified culture technique for Corynebacterium diphtheriae isolation from desiccated swabs.

Corynebacterium diphtheriae was isolated from pyoderma and ulcerative skin lesions with a modified delayed culture procedure as late as 9 weeks after field collection of silica gel-desiccated swabs. Biotypes gravis and mitis were identified. Most isolates were nontoxigenic. Todd-Hewitt broth enrichment enhanced recovery of C. diphtheriae by 70%.

Bacteriological Techniques↗

Capillary precipitin typing of Streptococcus pneumoniae.

The Neufeld test is presently the method of choice for typing Streptococcus pneumoniae. Although the test is reliable and relatively easy to perform, a simpler test, not requiring microscopic examination, would facilitate large-scale testing. A capillary precipitine test has been designed and tested for its usefulness in typing pneumococci. The type-specific carbohydrate antigens were obtained from broth culture supernatants. The antigens were reacted with type-specific antisera in glass capillary pipettes. Results from 82 reference antigens and 166 antigens from diagnostic pneumococcal strains showed that the reactions ere specific, and the results agreed with Neufeld test results. These results indicate that the precipitin test is as specific as the Neufeld test. The test is easy to perform, requires small amounts of antiserum, and can be completed in a short period of time.

Humans↗

Physiological differentiation of viridans streptococci.

Twelve hundred and twenty-seven clinical isolates and eighty stock strains of viridans streptococci were tested for serological and physiological characteristics. Because the serological reactions of these strains varied, a differentiation scheme could not be based on these reactions. For the same reason, there could be no correlation of serological characteristics with physiological characteristics. Nearly 97% of the clinical isolates were speciated by differences in physiological characteristics. Ten different physiological species were recognized. The physiological speciation scheme was based on stable enzymatic reactions rather than on results of tolerance tests. The study included air-tolerant anaerobic streptococcal strains as well as viridans streptococcal strains not normally found in humans. The differentiation scheme and nomenclature of the author are related to those of other investigators. Differences in the distribution of species isolated from different clinical sources and human infections were also noted. A key for the differentiation of human isolates of viridans streptococci is proposed.

Humans↗

The gram positive cocci.

Recent changes in taxonomy of the gram positive cocci are discussed. Views on these changes and practical methods of differentiating the staphylococci, micrococci, streptococci, and aerococci are presented. Simplified schemes, using acceptable clinical laboratory techniques, are presented that either differentiate or categorize the pathologically important gram positive coccal species.

Bacteria↗

Enzyme-linked immunosorbent assay for streptococcal M protein antibodies.

The enzyme-linked immunosorbent assay (ELISA) described by Engvall and Perlmann, which uses antigen-coated tubes and enzyme-labeled anti-immunoglobulin, has been used for the detection of antibodies against streptococcal M protein. The antigen used in the assay was obtained by guanidine extraction of type M-12 streptococcal cell walls followed by hydroxyapatite chromatography. This antigen has the capacity to elicit bactericidal antibodies in rabbits. The results show that the ELISA is specific and highly sensitive for the detection of antibodies in rabbit and human antisera. Preliminary results suggest that, when M-12 antigen is used, the antibodies detected by ELISA are the same antibodies detected in the bactericidal test. The assay has been performed with human and rabbit sera. There was a 96% agreement between bactericidal and ELISA results with rabbit sera and 97.5% agreement with human sera. All bactericidal antibody-positive sera tested thus far yielded positive ELISA results.

Alkaline Phosphatase↗

Nosocomial transmission of group B streptococci.

Group B streptococci are an important cause of infant septicemia and meningitis. A prospective study of group B streptococcal colonization in a 300-bed community hospital disclosed rates of 29% of 297 third-trimester women, 37% of 242 newborn infants, and 45% of 22 hospital personnel. Colonized parturients were more frequently black and anemic on admission for delivery. Infant colonization was statistically associated with a positive maternal genital culture, low birthweight, and prematurity. Nosocomial transmission of group B streptococci was strongly suggested by observations that 41% of colonized infants were born to culture-negative women and such infants became colonized later in their hospital stay than did colonized infants born to colonized women. Furthermore, hospital personnel working in the labor-delivery and nursery areas had a significantly higher prevalence of the organism than did personnel from other areas. Clearly, more information is needed about the epidemiology of group B streptococcal disease before appropriate and rational control measures can be recommended.

Adult↗

Possible nosocomial transmission of group B streptococci in a newborn nursery.

Within a six-day period in March, 1974, three infants born at a hospital in central Arkansas developed meningitis caused by group B, type III Streptococci. Three factors suggested nosocomial transmission of the organism in the nursery: (1) the three infants were born in a six-day period, (2) four weeks after their infants' births, none of the parents had positive cultures for group B streptococci, and (3) 31% of infants born in the hospital in March were colonized with group B, type III streptococci, while in April, after control measures in the nursery were instituted, only 2% of infants were colonized with this type (p less than 0.0002). Colonized infants were treated with penicillin, but follow-up cultures at two and six weeks showed that half the infants tested were still colonized. The number of personnel colonized with group B streptococci was not significantly different in personnel exposed to infants when compared with those that were not, and handwashing and environmental cultures were negative for group B streptococci. The results of this investigation give additional support to the concept that nosocomial transmission of group B streptococci can occur and may be effectively interrupted by control measures in the nursery.

Cross Infection↗

Guanidine extraction of streptococcal M protein.

A new method of extracting M protein from streptococcal cell walls has been presented. The extracting agent was guanidine-hydrochloride, a protein denaturant. The crude guanidine extract was further purified by ammonium sulfate and pH 5 fractionation and by hydroxyapatite column chromatography. Three major protein peaks were eluted from the hydroxyapatite column with 0.01, 0.1 and 0.3 M phosphate buffer, respectively. Protein fractions eluted at 0.1 and 0.3 M phosphate concentractions contained antigens that precipitated with homologous M-protein specific antisera, whereas the 0.01 M phosphate fraction had no immunological activity. The fraction eluted with 0.3 M phosphate was electrophoretically homogeneous in sodium dodecyl sulfate-acrylamide gels and elicited the production of bactericidal antibodies in rabbits. The 0.1 M phosphate buffer eluant was electrophoretically heterogeneous and did not elicit the production of bactericidal antibodies in rabbits.

Animals↗

Antibiotic susceptibility of Streptococcus bovis and other group D streptococci causing endocarditis.

Seventy-four strains of Streptococcus bovis and 35 strains of enterococci (Streptococcus faecalis and its varieties, Streptococcus faecium and Streptococcus durans), most of which were isolated from patients with endocarditis, were tested for their susceptibility to penicillin, ampicillin, erythromycin, cephalothin, vancomycin, methicillin, tetracycline, chloramphenicol, kanamycin, streptomycin, and gentamicin. Minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) were determined by a microtiter broth dilution technique. All of these organisms are group D streptococci, but the S. bovis strains are not enterococci. On the basis of both MIC and MBC, the S. bovis strains were much more susceptibile in general to antibiotics then were the enterococcal strains. For the S. bovis strains, the lowest MICs were obtained with penicillin, ampicillin, and erythromycin, and the lowest MBCs with penicillin and ampicillin. Although these antibiotics were also the most active against the enterococci, the MICs and MBCs were much higher than obtained with the S. bovis strains. Gentamicin was the most active aminoglycoside. On the basis of in vitro susceptibility results, the S. bovis strains resemble the viridans streptococci rather than enterococci.

Anti-Bacterial Agents↗

Presumptive identification of group A, B, and D streptococci.

A battery of five tests was used for presumptive identification of the pathogenic streptococci. The non-serological methods included determination of hemolysis for all strains, bacitracin susceptibility for group A streptococci, hippurate hydrolysis by group B streptococci, and bile-esculin reaction for group D streptococci. Enterococcal group D streptococci were differentiated from non-enterococcal group D streptococci by 6.5% NaCl tolerance. Two other categories of streptococci resulted: beta-hemolytic streptococci non-groups A, B, or D; and alpha- or nonhemolytic streptococci, not enterococci, not further identified (viridans streptococci). The tests were used as a battery and not as single entities. In this manner more than 99% of the group A, 99% of the group B, 81% of the beta-hemolytic streptococci non-group A, B, or D, 99% of the group D enterococci, 97% of the group D non-enterococci, and 94% of the viridans streptococci were correctly identified.

Bacitracin↗