Sterilization of talc for pleurodesis. Available techniques, efficacy, and cost analysis

Our plain-English summary of Sterilization of talc for pleurodesis. Available techniques, efficacy, and cost analysis, by L. Kennedy, L.M. Vaughan, L.L. Steed, et al (Chest, 1995).

The study

• Authors: L. Kennedy, L.M. Vaughan, L.L. Steed, S.A. Sahn
• Journal: Chest
• Published: 1995;107(4):1032-4
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Although talc has been used as a pleurodesis agent since 1935, a sterilization protocol has not been established. We obtained USP asbestos-free talc from six different suppliers and sterilized each using dry heat, gamma irradiation, and ethylene oxide gas. Aerobic, anaerobic, and fungal cultures were obtained prior to sterilization, and 1, 30, and 90 days after sterilization. Bacillus species were cultured from all six unsterilized specimens and coagulase-negative Staphylococcus grew from two unsterilized specimens. No growth of organisms was found following any method of sterilization. The cost of sterilization per 5-g packet of talc was $4.74, $7.85, and $16.25 for heat, ethylene oxide, and gamma irradiation, respectively. In conclusion, untreated talc is not sterile. Sterilization by prolonged dry heat exposure, ethylene oxide gas, and gamma irradiation are all effective, with dry heat being the least expensive.

In plain English

This laboratory study, from the Medical University of South Carolina, asked whether talc used for pleurodesis carries germs, and how well three sterilization methods work. Talc has been used for pleurodesis since 1935, but no sterilization protocol had been established. The authors bought one pound of talc described as USP asbestos-free from each of six suppliers and divided it into 5-gram packets. Packets were left untreated or were sterilized with dry heat, ethylene oxide gas, or gamma irradiation. They were then tested for bacteria and fungi for up to 90 days. Untreated talc from every supplier grew Bacillus species. Untreated talc from two suppliers also grew coagulase-negative Staphylococcus when first tested, which the authors thought likely came from skin, instrument, or package contamination. No sterilized packet grew any organism. The cost per 5-gram packet was $4.74 for heat, $7.85 for ethylene oxide and $16.25 for gamma irradiation. The authors concluded that untreated talc is not sterile, that all three methods were effective, and that dry heat was cheapest. They noted that the sterile shelf life was unknown. The study tested for microbes, not asbestos.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory study of the microbiology of unsterilized talc and of three sterilization methods, with a cost analysis
• Who was studied: Talc (not patients) from six suppliers of USP talc found in chemical supply catalogues. One pound was bought from each supplier and divided into 5-g portions, with six samples per supplier for each condition (unsterilized, heat, ethylene oxide, gamma irradiation). Done at the Medical University of South Carolina, Charleston; manuscript received 1994.
• Exposure: Talc described as USP asbestos-free, either unsterilized or sterilized by dry heat (132°C for 6 h), ethylene oxide gas (12% ethylene oxide for 1.75 h), or gamma irradiation (30 kilograys, 565 min total exposure). The study did not measure asbestos.
• Main results:
  • Unsterilized talc from every supplier grew Bacillus species immediately and at 30 and 90 days after packaging.
  • Unsterilized specimens from suppliers 1 and 4 (Humco and City Chemical) grew coagulase-negative Staphylococcus when cultured immediately after packaging. The authors considered this likely due to skin, instrument, or package contamination.
  • None of the sterilized specimens, from any method, grew bacteria or fungi at any testing time.
  • No fungi were cultured from the specimens.
  • The cost of sterilization per 5-g packet was $4.74 for heat, $7.85 for ethylene oxide, and $16.25 for gamma irradiation. The total nonpharmacy cost for 25 packets was $118.65, $196.15 and $406.15, respectively.
  • After ethylene oxide sterilization, specimens tested after the standard 12-h aeration period still contained 2 ppm of gas. Specimens tested at 24 h were free of gas.
• The authors' conclusion: The authors concluded that untreated talc is not sterile and contains a Bacillus species. They found that prolonged dry heat, ethylene oxide gas, and gamma irradiation are all effective sterilization methods, with dry heat the least expensive.
• Limitations the authors state:
  • The sterile shelf life of the sterilized talc is unknown; further cultures were planned at 6 months and 1 year.
  • No attempt at sterile handling was made while the talc was packaged, which the authors link to the Staphylococcus found on initial cultures.
  • The authors state that the need for sterilization has not been clearly established in human studies, and they knew of no reports of patients given unsterilized talc.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Talc, Pleurodesis, Asbestos-Free Talc.

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• Medical thoracoscopic talc pleurodesis for chylothorax due to lymphoma: a case series — D.C. Mares, P.N. Mathur (1998)
• Survival in patients with malignant pleural effusion undergoing talc pleurodesis — M. Hassan, R.M. Mercer, et al. (2019)
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• Success rate of medical thoracoscopy and talc pleurodesis in malignant pleurisy: A single-centre experience — J. Leemans, C. Dooms, et al. (2018)

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