TY - JOUR
T1 - Modified Pseudomonas agar
T2 - new differential medium for the detection/enumeration of Pseudomonas aeruginosa in mineral water
AU - Ramalho, Rita
AU - Cunha, Joaquim
AU - Teixeira, Paula
AU - Gibbs, Paul A.
PY - 2002
Y1 - 2002
N2 - Pseudomonas aeruginosa has been implicated as a foodborne and waterborne pathogen and is now considered a primary infectious agent. In the present study, the survival of P. aeruginosa inoculated in mineral water was evaluated by drop counts on Pseudomonas Agar Base (PAB), PAB with CN supplement X107, PAB with cetrimide, PAB with nalidixic acid, and these media with added FeSO4. Initial counts, before starvation, were the same in all media tested. Following this period, P. aeruginosa became sensitive to PAB with added cetrimide. The addition of FeSO4 did not improve the recovery of stressed P. aeruginosa but gave colonies a typical dark brown colour being easily differentiated from other species that can grow at 42°C. The modified Pseudomonas agar medium was also tested with several P. aeruginosa strains, other species of Pseudomonas, and other genera. Only P. aeruginosa strains (pyocyanin positive) produced the typical colonies. Our results demonstrate that Pseudomonas agar with ferrous sulphate, used for the differentiation of P. aeruginosa colonies, and nalidixic acid, used as an inhibitor of Gram-positive bacteria, might be a useful medium for the detection of injured P. aeruginosa in mineral water.
AB - Pseudomonas aeruginosa has been implicated as a foodborne and waterborne pathogen and is now considered a primary infectious agent. In the present study, the survival of P. aeruginosa inoculated in mineral water was evaluated by drop counts on Pseudomonas Agar Base (PAB), PAB with CN supplement X107, PAB with cetrimide, PAB with nalidixic acid, and these media with added FeSO4. Initial counts, before starvation, were the same in all media tested. Following this period, P. aeruginosa became sensitive to PAB with added cetrimide. The addition of FeSO4 did not improve the recovery of stressed P. aeruginosa but gave colonies a typical dark brown colour being easily differentiated from other species that can grow at 42°C. The modified Pseudomonas agar medium was also tested with several P. aeruginosa strains, other species of Pseudomonas, and other genera. Only P. aeruginosa strains (pyocyanin positive) produced the typical colonies. Our results demonstrate that Pseudomonas agar with ferrous sulphate, used for the differentiation of P. aeruginosa colonies, and nalidixic acid, used as an inhibitor of Gram-positive bacteria, might be a useful medium for the detection of injured P. aeruginosa in mineral water.
KW - Cetrimide
KW - Mineral water
KW - Nalidixic acid
KW - P. aeruginosa
KW - Pyocyanin
UR - http://www.scopus.com/inward/record.url?scp=0036141193&partnerID=8YFLogxK
U2 - 10.1016/S0167-7012(01)00365-7
DO - 10.1016/S0167-7012(01)00365-7
M3 - Article
C2 - 11777584
AN - SCOPUS:0036141193
SN - 0167-7012
VL - 49
SP - 69
EP - 74
JO - Journal of Microbiological Methods
JF - Journal of Microbiological Methods
IS - 1
ER -