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S D Allen

Publications and source records attributed to S D Allen.

At least 37 records · Page 2Linked to original sources
PubMed1995

Tentative criteria for determining the in vitro susceptibilities of Haemophilus influenzae, including quality control parameters, to two fluoroquinolones (grepafloxacin and PD 131628).

Grepafloxacin (OPC 17116) and PD 131628 were evaluated against 150 Haemophilus influenzae isolates to propose susceptibility testing criteria for both broth dilution and disk diffusion procedures using haemophilus test medium. Grepafloxacin-susceptible isolates are defined as those for which minimum inhibitory concentrations (MICs) are < or = 0.06 micrograms/ml and zones of inhibition are > or = 27 mm. PD 131628-susceptible strains of H. influenzae included those that exhibited MICs < or = 0.03 micrograms/ml, and the zones were > or = 32 mm. All MICs were well below concentrations that can be achieved in the blood and tissues of patients treated with either study drug. Criteria for defining a resistant category cannot be determined until strains with elevated MICs are available for study. The proposed quality control guidelines for H. influenzae ATCC 49247 and the disk test are 32-39 mm in diameter for grepafloxacin and 34-42 mm for PD 131628. The preliminary broth microdilution MIC control limits for this strain are 0.002-0.016 micrograms/ml for grepafloxacin and 0.002-0.008 micrograms/ml for PD 131628.

Anti-Infective Agents↗
PubMed1995

Cellular fatty acid analysis in the differentiation of Clostridium in the clinical microbiology laboratory.

The identification of Clostridium species can be problematic for the diagnostic microbiology laboratory. The introduction of the MIDI Microbial Identification System (MIS) has enabled personnel in diagnostic laboratories to perform cellular fatty acid analyses on a variety of microorganisms. We used the Virginia Polytechnic Institute (Blacksburg, VA) Anaerobe Library (Moore Version 3.8) to perform analyses on 216 strains representing 18 species of Clostridium. The organisms were characterized with use of traditional biochemical methods that employ prereduced anaerobically sterilized media and other reference diagnostic methods. The MIS identified 86% of the strains correctly to the species level without the need for supplemental tests, and identified an additional 6% of the strains to species levels with the aid of a few supplemental tests. Only 3% of strains were identified by genus incorrectly. The cellular fatty acid patterns of selected, medically important clostridia were so distinctive that 100% of these species were identified correctly. The MIS has many practical benefits, including speed of identification, and few disadvantages (such as equipment cost) for the clinical microbiology laboratory.

Bacterial Typing Techniques↗
PubMed1995

Tests for susceptibility of Streptococcus pneumoniae to cefdinir: proposed interpretive criteria and quality control parameters for both microdilution and disc diffusion methods.

Proposed quality control (QC) parameters for susceptibility testing of Streptococcus pneumoniae to cefdinir were developed following the procedure recommended by the National Committee for Clinical Laboratory Standards. The proposed QC MIC range for microdilution susceptibility testing of S. pneumoniae ATCC 49619 is 0.06-0.25 mg/L. The proposed QC limits for inhibitory zone diameters of S. pneumoniae ATCC 49619 around 5 micrograms cefdinir disks is 26-31 mm. We recommend the following for tentative interpretive criteria for determining the susceptibility of S. pneumoniae to cefdinir: susceptible, MIC < or = 0.5 mg/L or inhibition zone diameter > or = 23 mm; intermediate, MIC 1.0 mg/L or inhibition zone, 20-22 mm; resistant, MIC > or = 2.0 mg/L or inhibition zone diameter, < or = 19 mm for broth microdilution and disc diffusion tests, respectively.

Cefdinir↗
PubMed1995

Interpretive criteria and quality control parameters for testing bacterial susceptibility to the fluoroquinolone PD131628.

For testing bacterial susceptibility to PD131628, a 5-micrograms disk and the following tentative interpretive criteria may be used: > or = 19 mm for susceptible (MIC, < or = 1.0 micrograms/ml), 16 to 18 mm for intermediate (MIC, 2.0 micrograms/ml), and < or = 15 mm for resistant (MIC, > or = 4.0 micrograms/ml). For standard quality control strains, the following limits are proposed: for Escherichia coli ATCC 25922, zones of 31 to 41 mm or a MIC of 0.002 to 0.016 micrograms/ml; for Pseudomonas aeruginosa ATCC 27853, zones of 26 to 34 mm or a MIC of 0.12 to 0.5 micrograms/ml; for Staphylococcus aureus ATCC 25923, zones of 27 to 33 mm; for Staphylococcus aureus ATCC 29213, a MIC of 0.03 to 0.12 micrograms/ml; and for Enterococcus faecalis ATCC 29212, a MIC of 0.12 to 0.5 micrograms/ml.

Anti-Infective Agents↗
PubMed1995

Current issues and problems in dealing with anaerobes in the clinical laboratory.

Because of the current concern for health care reform and the demands placed in the clinical microbiology laboratory by decreased resources, questions regarding appropriate work-up of anaerobes remains unresolved. Although anaerobes are ubiquitous, the number of anaerobes causing disease is relatively few. This article focuses on the need for isolation and identification of these anaerobes and emphasizes proper collection, culture, and identification techniques. Varying levels of expertise in isolation and identification of anaerobes are proposed, and the role of "rapid" identification kits in identification of these organisms is discussed.

Bacteria, Anaerobic↗
PubMed1994

Infection prevention in severely myelosuppressed patients: a comparison between ciprofloxacin and a regimen of selective antibiotic modulation of the intestinal flora.

PURPOSE: To study whether oral ciprofloxacin would be as effective in preventing bacterial infections in severely myelosuppressed patients as selective antibiotic modulation of the gut flora with neomycin/polymyxin B sulfate/nalidixic acid (NPN). PATIENTS AND METHODS: One hundred and five patients undergoing allogeneic or autologous bone marrow transplant, or induction therapy for acute leukemia in 1988 and 1989 were studied. Patients were stratified according to the type of therapy, and randomized in a ratio of 2:1 to either oral ciprofloxacin 500 mg BID, or a combination of oral neomycin 250 mg QID, polymyxin-B 100 mg QID, and oral nalidixic acid 1,000 mg BID. Treatment began on admission and continued until the absolute granulocyte count was greater than 500/mm3 for 3 consecutive days. RESULTS: The 96 evaluable patients were evenly distributed over the 3 treatment groups; 63 patients received ciprofloxacin and 33 received NPN. Fever developed in 92% of patients on ciprofloxacin and in 97% of patients on NPN. (P = 0.66), 6.6 +/- 5.8 and 7.2 +/- 5.3 days from the start of prophylaxis, respectively. Twenty-five patients on ciprofloxacin developed 29 microbiologically documented infections, fewer than the 26 infections in the 22 patients on NPN (P = 0.02). Patients on ciprofloxacin had fewer bacteremias (33%) than did the NPN patients (55%) (P = 0.05). Gram-negative bacteremias were very rare (2 cases; no Enterobacteriaceae), but streptococcal bacteremias were frequent in both arms (27 cases). Side effects were not significantly different, but compliance with ciprofloxacin was better. CONCLUSIONS: Ciprofloxacin is at least as effective as the combination of neomycin/polymyxin/nalidixic acid in the prophylaxis of bacterial infections in myelosuppressed patients, and is better tolerated. Additional agents to prevent streptococcal infections are needed.

Adolescent↗
PubMed1994

Prophylactic efficacy of aerosolized liposomal (AmBisome) and non-liposomal (Fungizone) amphotericin B in murine pulmonary aspergillosis.

Pulmonary aspergillosis is a serious opportunistic disease in patients with immune suppression. Prophylactic measures would be highly beneficial because treatment often fails after infection occurs. The principle objective of this study was to evaluate the prophylactic efficacy of aerosolized liposomal (AmBisome) and non-liposomal (Fungizone) amphotericin B in a murine model. Immunocompromised mice were treated prophylactically for 3 days with AmBisome or Fungizone using a small particle aerosol generator. Intranasal challenge was with a high (10(8)), medium (10(7)), or low (10(6)) level of Aspergillus fumigatus spores. AmBisome nebulized more uniformly, resulting in very consistent chamber air concentrations. Total dose, however, was nearly the same for each formulation. Survival was prolonged in animals treated with both formulations at the 10(8) and 10(7) challenge levels. Quantitative lung cultures showed that organisms were completely cleared from the lungs in the low challenged group, with both formulations, whereas the high challenge proved overwhelming for both formulations. With the middle challenge, however, AmBisome cleared 80% of the lungs, whereas Fungizone cleared none. Lung drug retention of AmBisome treated animals was more than eight times higher than Fungizone at the time of challenge. BUN and creatinine values in animals treated with both formulations were not elevated. These results suggest that AmBisome is more effective than Fungizone when given as a prophylactic aerosol in this model.

Aerosols↗
PubMed1994

Identification of antigens of pathogenic free-living amoebae by protein immunoblotting with rabbit immune and human sera.

Prominent antigens of pathogenic and nonpathogenic free-living amoebae were identified by using polyclonal rabbit immune sera in immunoblot assays. The intent was to determine if prominent epitopes identified with rabbit immune sera could also be recognized by human sera. With rabbit sera, the development of immunoreactive bands was restricted to molecular masses of greater than 18.5 kDa for Naegleria, Hartmannella, and Vahlkampfia antigens. Two or more broad bands of less than 18.5 kDa were prominent features in three different Acanthamoeba species. Few cross-reactive antibodies could be detected between representative species of the three different subgroups of Acanthamoeba. Naegleria antigen was likewise serologically distinct, as were Hartmannella and Vahlkampfia antigens. The relative lack of cross-reacting antibodies between the pathogenic amoebae suggested that i would be desirable to use a panel of amoebic antigens to represent the range of serologically distinct antigens for assessing reactive antibodies in human sera. In pooled human sera (10 serum specimens per pool), the appearance of minimally reactive bands ranging from 32.5 to 106 kDa was a common feature of all six antigens. A prominent band of less than 18.5 kDa was identified in the Acanthamoeba culbertsoni antigen lane in 2 of the 10 human serum specimen pools. When sera from each of the two groups were tested individually by immunoblotting, the reaction with A. culbertsoni antigen could be associated with one individual. By using a panel of amoebic antigens, this method could prove useful in recognizing undiagnosed amoebic infections by revealing specific reactive antibodies.

Acanthamoeba↗
PubMed1993

Interpretive criteria and quality control parameters for determining bacterial susceptibility to fosfomycin tromethamine.

Studies with fosfomycin tromethamine disks containing 200 micrograms of fosfomycin and 50 micrograms of glucose-6-phosphate confirmed the following zone diameter criteria for the NCCLS method: < or = 12 mm for resistant (MIC > or = 256 micrograms/ml), 13-15 mm for intermediate (MIC 128 micrograms/ml) and > or = 16 mm for susceptible (MIC < or = 64 micrograms/ml). Additional studies defined acceptable MIC and zone diameter ranges for the following quality control strains: Escherichia coli ATCC 25922, MIC 0.5 to 4.0 micrograms/ml, zone diameter 23 to 29 mm; Staphylococcus aureus ATCC 25923, zone diameter 26 to 32 mm; Pseudomonas aeruginosa ATCC 27813, MIC 2.0 to 8.0 micrograms/ml; and Enterococcus faecalis, ATCC 29212, MIC 16 to 64 micrograms/ml.

Bacteria↗
PubMed1993

In vitro comparison activity of OPC-17116, a new fluoroquinolone, against more than 5,000 recent clinical isolates from five medical centers.

The in vitro activity of OPC-17116, a new fluoroquinolone, was compared with those of ciprofloxacin, ofloxacin and cefixime. A total of 5,231 fresh clinical isolates from five geographically separate US medical centers were tested. The primary results of this study are: 1. OPC-17116 is very active against Enterobacteriaceae [MIC90s, 0.015-1 microgram/ml, except Providencia rettgeri (MIC90, > 8 micrograms/ml)], 2. among nonenteric Gram-negative bacilli (e.g. Xanthomonas maltophilia, MIC90, 2 micrograms/ml) and Gram-positive cocci (e.g. oxacillin-susceptible staphylococci, MIC90s, 0.12-0.5 microgram/ml) OPC-17116 demonstrated higher activity than ciprofloxacin or ofloxacin, 3. the quinolones were more active than cefixime against most of the species tested, especially against Gram-positive and non-enteric Gram-negative organisms. The results of this study, associated with prior documented favorable qualities, support continued investigation of OPC-17116 for clinical use.

Anti-Infective Agents↗
PubMed1993

Methods for testing the susceptibility of anaerobic bacteria to two fluoroquinolone compounds, PD 131628 and clinafloxacin.

The susceptibility of anaerobic bacteria to two new fluoroquinolones, PD 131628 (the bioactive form of PD 131112 or CI-990) and clinafloxacin (CI-960 or PD 127391), was determined with the agar dilution procedures and two media, and one broth microdilution procedure. Sparfloxacin and ciprofloxacin were also tested by the broth microdilution method. One hundred anaerobic isolates and four control strains were tested by the three methods which gave minimum inhibitory concentrations (MICs) that were essentially comparable, but not identical. With the broth microdilution method, the relative potency of the four fluoroquinolones was: clinafloxacin > PD 131628 > sparfloxacin > ciprofloxacin. For the latter three drugs but not clinafloxacin, the MIC values were often near the proposed interpretive breakpoint concentrations, and thus minor methodological differences frequently influenced the interpretive categories. Replicate agar dilution tests in five laboratories established MIC control limits for each of four control strains: those MIC limits could also be used to define the expected performance of the two alternative methods.

Anti-Infective Agents↗
PubMed1993

Immunological effects of amphotericin B and liposomal amphotericin B on splenocytes from immune-normal and immune-compromised mice.

The immunological effects of amphotericin B and liposomal amphotericin B were studied in vitro by measuring B- and T-lymphocyte proliferation on splenocytes from immune-normal, cyclosporine-compromised, and cyclophosphamide-compromised mice. Cellular viability of cells from immune-normal mice was also evaluated. The concentrations used (0, 0.5, 1, 2, 4, 8, and 16 micrograms/ml) encompassed clinically relevant doses. Amphotericin B consistently reduced the abilities of B cells and T cells to proliferate, especially when administered at higher than clinically relevant doses. Direct cytotoxicity probably played only a minor role, since viability studies showed that, compared with its liposomal analog, amphotericin B reduced the number of viable cells by no more than 10%. Clinically relevant doses of liposomal amphotericin B (A. S. Janoff, L. T. Boni, M. C. Popescu, S. R. Minchey, P. R. Cullis, T. D. Madden, T. Tarashi, S. M. Gruner, E. Shyamsunder, M. W. Tate, R. Mendelsohn, and D. Bonner, Proc. Natl. Acad. Sci. USA 85:6122-6126, 1988; R. Mehta, G. Lopez-Berestein, R. Hopfer, K. Mills, and R. L. Juliano, Biochim. Biophys. Acta 770:230-234, 1984) did not inhibit any of the immune parameters examined. Liposomes may, therefore, be a useful means of delivering more drug to a host infected with a fungal organism without further compromising the patient's already suppressed immune system.

Amphotericin B↗