Low-frequency transduction of imipenem resistance and high-frequency transduction of ceftazidime and aztreonam resistance by the bacteriophage AP-151isolated from a Pseudomonas aeruginosa strain
J. Blahova et al., Low-frequency transduction of imipenem resistance and high-frequency transduction of ceftazidime and aztreonam resistance by the bacteriophage AP-151isolated from a Pseudomonas aeruginosa strain, J CHEMOTHER, 12(6), 2000, pp. 482-486
Bacteriophage AP-151, isolated from a multidrug resistant Pseudomonas aerug
inosa strain, was found to transduce antibiotic resistance determinants to
recipient strains of P. aeruginosa. Resistance to cefotaxime, ceftazidime,
aztreonam, imipenem and meropenem was transduced as a block, at different f
requencies, to two P, aeruginosa strains. Resistance was two logarithms hig
her (in the range 10(-5)) for cefotaxime, ceftazidime or aztreonam than for
imipenem in recipient strain PAO-1670. The frequency of transduced imipene
m resistance was also lower in recipient strain ML-1008, This phenomenon re
flects the difference in the lytic activity of AP-151 in both strains, as t
he titer of the AP-151 phage in the PAO strain was found to be restricted t
o 10(-4)-10(-5) in contrast to the titer of the same phage in the ML strain
which was 10(-10). The limited lytic activity in the PAO recipient strain
was correlated with higher transducing activity. It can be concluded that s
ome wild-type bacteriophages of P, aeruginosa might have highly individual
relations between lytic and transducing activity in various potential recip
ient nosocomial strains of P, aeruginosa, The nature of resistance to cefta
zidime and imipenem was studied using clavulanate and EDTA as inhibitors of
individual class of beta-lactamases, indicating the presence of extended-s
pectrum beta-lactamase and a metallo-beta-lactamase in this isolate.