Biomedical subjects

R Lannigan

Publications and source records attributed to R Lannigan.

At least 19 recordsLinked to original sources

PubMed1992

Evaluation of MicroScan Rapid Pos Combo panels for identification of staphylococci.

MicroScan Rapid Pos Combo panels (Baxter Diagnostics, Inc., MicroScan, West Sacramento, Calif.) contain substrates conjugated with fluorophores and substrates with a fluorescent pH indicator. AutoSCAn W/A, an automated panel processor equipped with a fluorometer, reads the panels after 2 h of incubation and can identify staphylococci to the species level. We tested 239 strains belonging to 17 species of staphylococci. All the strains were identified by conventional methods (W.E. Kloos and K.H. Schleifer, J. Clin. Microbiol. 1:82-88, 1975) and by the MicroScan Rapid ID system. The system correctly identified 219 (91.6%) strains; nine (3.8%) identification results were probably correct, and six (2.5%) results were incorrect. The system designated five (2.1%) strains as rare biotypes. The automated MicroScan Rapid ID system is useful and reliable in identifying most human isolates of staphylococci encountered in the clinical laboratory.

Bacterial Typing Techniques↗

PubMed1991

Gas-liquid chromatographic analysis of cellular fatty acids for identification of gram-negative anaerobic bacilli.

A commercially available, computer-assisted microbial identification system (MIS) employs gas-liquid chromatographic analysis of cellular fatty acids for bacterial identification. MIS was compared with conventional identification systems. Of 225 gram-negative anaerobes tested, MIS identified 72.4% of the strains to the species level, 88.9% to the appropriate group, and 93.3% to the correct genus.

Bacteriological Techniques↗

PubMed1990

Accuracy and reproducibility of the MicroScan rapid anaerobe identification system with an automated reader.

Rapid anaerobe identification (MicroScan) panels (4 h) were evaluated both visually and by the AutoScan-4, a computer-controlled microplate reader. The results of both reading methods were compared with identifications obtained by the conventional (Virginia Polytechnic Institute) method. In total, 237 anaerobes were tested. Correct identifications were obtained for 166 strains (70%) by visual reading and 157 strains (66.2%) by the AutoScan-4. Supplementary tests resulted in 80.1 and 76.7% total correct identifications, respectively. Comparison of the two reading methods revealed complete agreement for 169 strains. Differences between the two reading methods were due to difficulties in reading specific reactions. This was especially true with the clostridial species. The performance of the MicroScan system in the identification of anaerobic bacteria appears comparable to that of other 4-h identification systems for anaerobes, but this system shows significant variance from the conventional system. Improvements in the trays and data base are required before the system can be recommended for routine use.

Autoanalysis↗

PubMed1989

Immunoregulation in Heymann nephritis. I. Cell marker studies.

Immunoregulation was examined in rats with Heymann nephritis (HN), an established model of membranous glomerulonephropathy (MGN). There is little known of the cellular immune events for the induction and maintenance of the autoimmune response in HN. The cell marker studies utilized fluorescein (FITC)-labelled monoclonal antibodies directed to B cells (Mark-I), and T cell subsets: pan T (ER-I), helper/inducer T (ER-2) and suppressor/cytotoxic T (ER-3). Lymphoid subsets were compared in spleen, lymph nodes, peripheral blood and bone marrow, of normal and diseased rats. Animals were investigated during the induction and chronic phases of disease. The induction of HN was associated with an early, significant, but transient increase of the non-specific myeloid component of the defence system. Subsequently, a significant increase was seen in the number of cells of the B lymphocyte lineage in HN animals, which coincided well with the overall increased humoral immune responsiveness. No alterations in the T lymphocyte subsets were noted during the development of this experimental autoimmune disease.

Animals↗

PubMed1989

Immunoregulation in Heymann nephritis. II. Functional studies.

In this study, the functional properties of the cells involved in the immunoregulation of Heymann nephritis (HN) have been investigated. HN is a disease model in the rat where the pathology closely resembles membranous glomerulonephropathy (MGN) in man. This autoimmune model is induced by injection of renal tubular antigen (RTA) incorporated in Freund's complete adjuvant (FCA). The strong B cell and plasma cell response in the chronic phase of HN, as determined by cell marker analyses, is predominantly antigen-non-specific. The secondary response pattern found was not only to RTA upon repeated immunization, but also to non-related antigen (SRBC). Although cell marker studies have indicated no major quantitative changes in the T cell population throughout the development of HN, a severe deregulation of the cellular immune response is observed especially during the induction period of HN. This was shown by a strong decrease of the mitogen-induced proliferative response and IL-2 production. This phenomenon is caused by both defective cellular components and inhibitory serological factors. Finally, in the chronic phase, these aberrations gradually return to normal.

Animals↗

PubMed1988

Pulmonary cavitation due to Neisseria mucosa in a child with chronic neutropenia.

A case of spontaneous pulmonary abscess with cavitation caused by Neisseria mucosa in a chronically neutropenic child is reported. Neisseria mucosa was isolated as the sole pathogen from a percutaneous needle aspirate. It appears that the clinical course of the pulmonary lesion was indolent. Interestingly, a gallium scan was diagnostic for pulmonary abscess even though the child was neutropenic.

Adolescent↗

PubMed1988

Microbiological investigation of an outbreak of bacteraemia due to Streptococcus faecalis in an intensive care unit.

An increased incidence of bacteraemia due to Streptococcus faecalis in a Critical Care and Trauma Centre (CCTC) during November 1985 prompted investigation. During the epidemic 21 blood cultures from five CCTC patients were positive for S. faecalis. A point prevalence culture survey revealed two more strains from wounds from two of these five patients. Fifteen strains from blood cultures and the two strains from wound sites were further characterized by conventional biotyping methods and susceptibility patterns, but they could not be differentiated from 40 unrelated control strains by these methods. The API-20S and the API-ZYM systems, however, were able to distinguish the outbreak isolates from the control strains. This investigation supports the hypothesis that S. faecalis is capable of causing cross-infection, and it may be necessary to characterize enterococci beyond routine tests to identify an outbreak due to this organism.

Adult↗

PubMed1987

Comparison of RapID-ANA and Minitek with a conventional method for biochemical identification of anaerobes.

Two micromethods for the identification of anaerobes, one requiring growth (Minitek) and one nongrowth dependent (RapID-ANA), were compared with a conventional identification culture system. For 222 clinical isolates, RapID-ANA agreed with PRAS in 187 (84%) and Minitek agreed for only 170 strains (76%). Both systems identified common isolates well, but encountered some difficulty in identifying less common clostridia and Gram-negative bacilli. Although adequate for most strains, the results from both systems should be interpreted with caution, particularly for less frequently isolated species.

Bacteria, Anaerobic↗

PubMed1987

Comparison of susceptibility results of anaerobic organisms determined by agar dilution method and Sceptor Anaerobe MIC/ID Micro Broth Dilution Panels.

A commercial broth microdilution system (Sceptor Anaerobe MIC/ID, BBL) for susceptibility testing of anaerobic bacteria was compared to a reference agar dilution system. Of the 172 organisms tested, only 7% failed to grow sufficiently for testing in the Sceptor system. In 1,590 antibiotic/organism combinations, 86.7% of the Sceptor results were identical or within one doubling dilution of the reference system. In 91.9% of the cases, interpretation of the results was same in both systems. Two hundred and twelve MIC values, however, differ by greater than or equal to 2 log2 dilution from the reference system. Due to this reduced correlation in the actual MIC values with the reference results, further studies are warranted before the Sceptor system can be recommended for routine use.

Agar↗

PubMed1987

Supplement peptone agar--a simple carbohydrate degradation plate medium for the identification of Neisseria species.

A carbohydrate degradation medium was developed for the detection of acid production by Neisseria species and Branhamella catarrhalis. A total of 223 clinical isolates were identified by Supplemented Peptone Agar and the results were compared with those of Cystine Trypticase Agar. Supplemented Peptone Agar and Cystine Trypticase Agar correctly identified 99.1% and 93.7% of the total strains respectively within 24 h. With Cystine Trypticase Agar method another 4% of the isolates could be identified but required an additional 24 h of incubation.

Culture Media↗

PubMed1987

Endophthalmitis due to Oerskovia xanthineolytica.

Unilateral endophthalmitis developed in a 47-year-old man following an intraocular eye injury with a metallic foreign body. Eventually, Oerskovia xanthineolytica was isolated from the vitreous humour. To our knowledge this is the first documented case of endophthalmitis caused by this organism in humans. The clinical course and management of this opportunistic infection are discussed.

Bacterial Infections↗

PubMed1986

Comparison of the MicroScan system with the API Staph-Ident system for species identification of coagulase-negative staphylococci.

To evaluate the accuracy of the MicroScan System (American Hospital Supply Corp., Sacramento, Calif.) for identification of coagulase-negative staphylococci, we tested 175 clinical isolates of coagulase-negative staphylococci. The results obtained by the MicroScan system were compared with those of the API Staph-Ident system (Analytab Products, Plainview, N.Y.). Forty-three discrepancies between the two systems were resolved by the conventional method of Kloos and Schleifer (W.E. Kloos and K.H. Schleifer, J. Clin. Microbiol. 1:82-88, 1975). The MicroScan and the Staph-Ident systems correctly identified 146 (86.4%) and 154 (88%) of 175 strains, respectively. The API system failed to identify phosphatase-negative Staphylococcus epidermidis. The MicroScan system demonstrated the greatest accuracy in the identification of S. epidermidis and S. saprophyticus, whereas lesser accuracy was achieved with S. hominis, S. warneri, and S. sciuri.

Bacteriological Techniques↗

PubMed1986

Effect of cationic proteins on the glomerular deposition of anionic proteins and immune complexes.

When 3 mg of cationized human IgG (cIgG, pI greater than 9) was injected intravenously into mice and followed 15 min later by 3 mg anionized bovine serum albumin (aBSA, pI = 4), deposits were detected along the capillary loops and in the mesangium. Additional infusion of immunoaffinity-purified rabbit anti-BSA antibodies 1 h later led to their deposition at the same location. Intravenous injection of an equivalent amount of preformed BSA-anti-BSA or aBSA-anti-BSA immune complexes into mice with glomerular planted cIgG gave rise to few deposits. Similarly, the perfusion of preformed aBSA-anti-BSA complexes in isolated rat kidneys with planted cIgG led to granular deposition of both, but the intensity of staining was less than when sequential perfusions were used. Cationic macromolecules bound to the glomerulus may lead to the deposition of anionic macromolecules and anionic immune complexes.

Animals↗

PubMed1986

Stimulation of circulating autoantibody levels in the rat with established progressive passive Heymann nephritis.

Rats with established progressive passive Heymann nephritis (PPHN) were stimulated with tubular nephritogenic antigen derived from rat kidney fraction 3 (rKF3) or heterologous antibody to the eKF3 antigen. Rats stimulated with antigen had elevated levels of circulating autoantibody and increased amounts of rat IgG in a beaded pattern around the glomerular capillaries. The brush border (BB) region of the proximal convoluted tubules also stained for rat IgG. Rats stimulated with antibody had similar changes, but in addition the injected antibody was demonstrated in the glomerular deposits and in the BB region of the proximal convoluted tubules. Proteinuria was markedly increased in the antibody injected rats. This study indicates that the cells of the 'primed' immune system of rats with PPHN can be stimulated by 'additional' rKF3 antigen or antibody to it, to produce increased levels of circulating autoantibody. It is suggested that the progression of PPHN is dependent on the availability and access of the nephritogenic autoantigen to the immune system and that autoantigen may be released by autoantibody.

Animals↗

PubMed1986

Passive Heymann nephritis in pre- and post-natal rats.

Passive Heymann nephritis (PHN) was induced in pre- and post-natal rats by a single intra-peritoneal injection of 0.2 ml of a rabbit anti-rat kidney fraction 3 (rKF3) antibody. Immune complex formation occurred only in those glomeruli or parts of glomeruli which were open to the circulation. Double staining of kidney sections for the glomerular nephritogenic antigen and rabbit IgG, 2 days after the injection of the antibody showed an identical distribution of both components in the glomeruli. In rats killed more than 4 days after the injection of the anti-rKF3 antibody, the nephritogenic antigen could be demonstrated in the subcapsular glomeruli, in the absence of rabbit IgG; and the same applied when the kidneys had reached maturity. When the injected antibody was expected to be present in the circulation, no nephritogenic antigen was demonstrated in the glomeruli in the absence of the heterologous IgG. These observations indicate that the nephritogenic antigen appears in the glomerulus at the same time as the glomerular capillary loops open to the circulation. Unlike PHN in the adult rat, the immune complexes in the glomeruli of neonatal rats do not persist longer than 84 days.

Aging↗

PubMed1985

Streptococcus pyogenes as a cause of nosocomial infection in a critical care unit.

A cluster of five cases of Streptococcus pyogenes infection or colonization was identified in an adult critical care unit following the admission of a patient with a severe cutaneous infection. This report deals with the nature of the outbreak and methods of control, and comments on infections of this nature in adult critical care areas.

Adult↗

PubMed1985

Decreased susceptibility of Serratia marcescens to chlorhexidine related to the inner membrane.

An isolate of Serratia marcescens (strain 100) obtained from a handwashing solution of chlorhexidine (Hibitane) was found not to release potassium ions when exposed to chlorhexidine as compared to chlorhexidine susceptible clinical isolates of Escherichia coli and Ser. marcescens. Lysozyme-tris-EDTA spheroplast preparations of the Serratia isolates were also tested for potassium ion leakage following exposure to chlorhexidine and it was found that the inner membrane was responsible for the decreased susceptibility of the organism of chlorhexidine. These experiments suggested that the mechanism of increased resistance of strain 100 Ser. marcescens to chlorhexidine was an inner membrane change. The nature of the change is currently unknown.

Cell Membrane↗

PubMed1985

Efficacy of tetroxoprim/sulphadiazine in the treatment of Pneumocystis carinii pneumonitis in rats.

Pneumocystis carinii pneumonitis was induced using dexamethasone in male Sprague-Dawley rats. After the first death due to Pn. carinii occurred, nine rats received 50 mg/kg/day tetroxoprim and 120 mg/kg/day sulphadiazine. Four additional rats were given no therapy and served as a positive control. All the surviving rats including five negative controls were sacrificed four weeks after the last positive control rat died. All four rats in the positive control group and two of nine in the treated group developed Pn. carinii pneumonitis, whereas none of the five negative controls had evidence of Pn. carinii infection. The difference between the treated and untreated rats was significant (P = 0.05). These results suggest that combination therapy with tetroxoprim/sulphadiazine is effective in the treatment of Pn. carinii pneumonitis in this animal model.

Animals↗