PMID- 25720802
OWN - NLM
STAT- MEDLINE
DCOM- 20151223
LR  - 20150401
IS  - 1469-7629 (Electronic)
IS  - 0022-0299 (Linking)
VI  - 82
IP  - 2
DP  - 2015 May
TI  - Microbiological bioassay using Bacillus pumilus to detect tetracycline in milk.
PG  - 248-55
LID - 10.1017/S0022029915000138 [doi]
AB  - The tetracyclines (TCs) are widely used in the treatment of several diseases of 
      cattle and their residues may be present in milk. To control these residues it is 
      necessary to have available inexpensive screening methods, user-friendly and 
      capable of analysing a high number of samples. The purpose of this study was to 
      design a bioassay of microbiological inhibition in microtiter plates with spores 
      of Bacillus pumilus to detect TCs at concentrations corresponding to the Maximum 
      Residue Limits (MRLs). Several complementary experiments were performed to design 
      the bioassay. In the first study, we determined the concentration of spores that 
      produce a change in the bioassay's relative absorbance in a short time period. 
      Subsequently, we assessed the concentration of chloramphenicol required to 
      decrease the detection limit (DL) of TCs at MRLs levels. Thereafter, specificity, 
      DL and cross-specificity of the bioassay were estimated. The most appropriate 
      microbiological inhibition assay had a B. pumilus concentration of 1.6 x 10(9) 
      spores/ml, fortified with 2500 mug chloramphenicol/l (CAP) in Mueller Hinton 
      culture medium using brilliant black and toluidine blue as redox indicator. This 
      bioassay detected 117 mug chlortetracycline/l, 142 mug oxytetracycline/l and 105 mug 
      tetracycline/l by means of a change in the indicator's colour in a period of 5 h. 
      The method showed good specificity (97.9%) which decreased slightly (93.3%) in 
      milk samples with high somatic cell counts (>250,000 cells/ml). Furthermore, 
      other antimicrobials studied (except neomycin) must be present in milk at high 
      concentrations (from >5 to >100 MRLs) to produce positive results in this assay, 
      indicating a low cross specificity.
FAU - Tumini, Melisa
AU  - Tumini M
AD  - Catedra de Biofisica,Facultad de Ciencias Veterinarias,Universidad Nacional del 
      Litoral-R.P.L.,Kreder 2805,3080 Esperanza,Argentina.
FAU - Nagel, Orlando Guillermo
AU  - Nagel OG
AD  - Catedra de Biofisica,Facultad de Ciencias Veterinarias,Universidad Nacional del 
      Litoral-R.P.L.,Kreder 2805,3080 Esperanza,Argentina.
FAU - Althaus, Rafael Lisandro
AU  - Althaus RL
AD  - Catedra de Biofisica,Facultad de Ciencias Veterinarias,Universidad Nacional del 
      Litoral-R.P.L.,Kreder 2805,3080 Esperanza,Argentina.
LA  - eng
PT  - Journal Article
DEP - 20150227
PL  - England
TA  - J Dairy Res
JT  - The Journal of dairy research
JID - 2985125R
RN  - 0 (Anti-Bacterial Agents)
RN  - 0 (Tetracyclines)
SB  - IM
MH  - Animals
MH  - Anti-Bacterial Agents/chemistry/*pharmacology
MH  - Bacillus/*classification/*physiology
MH  - Biological Assay/veterinary
MH  - Cattle
MH  - Drug Residues
MH  - Female
MH  - Food Microbiology
MH  - Logistic Models
MH  - Milk/*chemistry
MH  - Tetracyclines/chemistry/*pharmacology
OTO - NOTNLM
OT  - tetracycline
EDAT- 2015/02/28 06:00
MHDA- 2015/12/24 06:00
CRDT- 2015/02/28 06:00
PHST- 2015/02/28 06:00 [entrez]
PHST- 2015/02/28 06:00 [pubmed]
PHST- 2015/12/24 06:00 [medline]
AID - S0022029915000138 [pii]
AID - 10.1017/S0022029915000138 [doi]
PST - ppublish
SO  - J Dairy Res. 2015 May;82(2):248-55. doi: 10.1017/S0022029915000138. Epub 2015 Feb 
      27.