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S L Carito

Publications and source records attributed to S L Carito.

5 recordsLinked to original sources
PubMed1988

Comparison of rapid NFT and API 20E with conventional methods for identification of gram-negative nonfermentative bacilli from pharmaceuticals and cosmetics.

The accuracy of the Rapid NFT and the API 20E identification systems was evaluated by comparing them with conventional biochemical methods for the identification of gram-negative, nonfermentative bacilli. The organisms were recovered from preserved, nonsterile pharmaceutical and cosmetic products. A total of 123 test isolates that are commonly encountered in these products were used. By using the criteria of accurate and reliable identification without employing additional tests, Rapid NFT was found to be more accurate after 48 h of incubation than API 20E for characterizing isolates to the species level. Therefore, close agreement between NFT and conventional methods for identification of industrial gram-negative isolates provides evidence that the Rapid NFT system is an improved and rapid method for identifying these organisms to the species level with minimal use of supplementary tests.

Cosmetics↗
PubMed1967

X-ray diffraction studies on selected bacterial cell walls.

The cell walls of selected bacteria were studied by X-ray diffraction analysis to determine and characterize crystalline components. The walls were isolated by mechanical disruption and purified by enzymatic and washing procedures. The X-ray diffraction lines which appeared from the gram-positive cell walls were shown to be due to the constituent "mucopeptide" fraction. No diffraction lines could be obtained from the gram-negative bacterium studied. The results show that crystallinity is associated with mucopeptide.

Bacillus cereus↗
PubMedDate not supplied

An evaluation of preservative adsorption onto nylon membrane filters.

Pharmaceutical drug products often contain antimicrobial agents as a preservative in their formulation. These excipients are required to destroy or impede the growth of microorganisms that inadvertently enter the product during manufacturing. Unfortunately, these preservatives may also interfere with microbiological assays used to determine product sterility or bioburden levels. The extent of interference by these preservatives can be quite significant, but varies depending on the method used. The most frequently used method for testing parenteral drug products is the membrane filtration technique. Membrane filters are composed of a wide variety of materials such as cellulose, polycarbonate, acrylic polypropylene, Teflon, and nylon. This study evaluated the adsorption characteristics that nylon filters, obtained from five different manufacturers, had on the filtration of solutions of four different antimicrobial compounds (phenol, methylparaben, propylparaben, and benzalkonium chloride). The adsorption properties were determined using both HPLC and microbiological assay techniques. The data revealed that there was a wide range in the amounts of antimicrobial agent (2.3 to 94.1%) bound to the membrane filters when direct product filtration was used without a subsequent rinse step. However, when a rinse step is included, only propylparaben showed any significant "true" adsorption (less than 1 to 33.3%), but showed only marginal bacterial inhibition. Interestingly, the microbiological assays indicated that with a saline rinse step, only benzalkonium chloride was lethal for the two challenge organisms even though the percent adsorbed as measured by HPLC was below 1%. This discrepancy is significant because it demonstrates the analytical limitation when using HPLC to detect minimal concentrations of benzalkonium chloride that may be deleterious to microorganisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adsorption↗
PubMedDate not supplied

The effect of refrigeration and mixing on detection of endotoxin in parenteral drugs using the Limulus Amebocyte Lysate (LAL) test.

Prior to testing for the presence of bacterial endotoxin, parenteral products are handled and stored in a variety of ways. Two incidents, detected by the U.S. Food and Drug Administration, revealed that differences in product handling and storage may have played a role in causing analytical discrepancies in the testing of identical samples. The testing procedure was the USP Bacterial Endotoxin test using Limulus Amebocyte Lysate (LAL) reagent. Consequently, an evaluation was made at the two principal factors that contributed to the suspected analytical anomaly. The factors were sample storage and the degree of agitation prior to sample analysis. Additional variables such as bacterial growth medium and adsorption potential of endotoxin by rubber stoppers were also evaluated. It was found that neither the medium employed to grow the E. coli endotoxin nor the storage temperature of the spiked solutions were problematic. However, it was shown that 20-40% of the spiked endotoxin was lost due to non-agitation of solution in vials in which the solution was in contact with the rubber stoppers. A suggested remedy for this problem is to store intact product containers in an upright position and to establish a uniform mixing procedure prior to endotoxin assay.

Endotoxins↗