We have lost many flasks due to contamination to B. cepacia. We have added Pen-Strep to no avail.
What are other antibiotics that could be used in culture media that does not belong to b-lactam or aminoglycosides class of antibiotics?
If the contamination is present from unopened bottles, I'd change the vendor or provider of liquid/sterile media. If media is prepared in the lab, I would start buying prepared media or if not possible then I would buy all filtration supplies and devices new and start from scratch. -
From my experience, the antibiotics just delay the outbreak of a certain contamination, they sadly do not actually kill the bacteria? Because there are still people getting contaminated culture even they have PS or anti-anti added. Getting good suppliers and having good aseptic techique may the final resolutions.
Did you do an antibiogram and typing? Is it always the same strain? B. cepacia strains can be VERY antibiotic resistant. I suggest to choose one or two antibiotics based on the strain(s)' antibiotic susceptibility profiles and cytotixicity towards eularyotic cells.
It appears that your Bacillus cepacia contaminant is a resistant one. However, you could try Meropenem, ceftazidime, minocycline, temocillin, and piperacillin/tazobactam separately or in combination. Preparation of the antibiotic and introduction protocols could be sources of concern. Please follow the protocols carefully to achieve the final exposure concentration suitable for the contaminant concentration.
Use a combination of amikacin (1 mg/ml) and ceftazidime (1 mg/ml). Check the following articles:
- Martin DW, Mohr CD. Invasion and intracellular survival of Burkholderia cepacia [published correction appears in Infect Immun 2000 Jun;68(6):3792]. Infect Immun. 2000;68(1):24-29. doi:10.1128/iai.68.1.24-29.2000.
- Burns J, Jonas M, Chi E, Clark D, Berger A, Griffith A. Invasion of respiratory epithelial cells by Burkholderia (Pseudomonas) cepacia. Infect Immun. 1996;64:4054–4059.
Good luck!
Assuming that you have observed all the aseptic techniques then I will recommend what Oscar has stated below;
Oscar L. Sierra added an answer
March 29
If the contamination is present from unopened bottles, I'd change the vendor or provider of liquid/sterile media. If media is prepared in the lab, I would start buying prepared media or if not possible then I would buy all filtration supplies and devices new and start from scratch
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