Observations on Bacteriophage Typing of Pseudomonas Aeruginosa

Postic, Boško; Finland, Maxwell

doi:10.1172/jci104432

Cited by 35 publications

(16 citation statements)

References 30 publications

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“…A total of 10 9 to 10 2 CFU of S242 was plated on a LB agar, and then 1 ml of concentrated phage suspension containing 10 9 phage particles was poured over the surface. After incubation overnight at 37°C, isolated colonies representing phageresistant bacteria were counted, and the rate of phage-resistant bacteria was calculated (37).…”

Section: Methodsmentioning

confidence: 99%

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Efficacy of Bacteriophage Therapy in Experimental Sepsis and Meningitis Caused by a Clone O25b:H4-ST131 Escherichia coli Strain Producing CTX-M-15

Pouillot

Chomton

Blois

et al. 2012

Antimicrob Agents Chemother

122

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bWe evaluated phage therapy in experimental infections due to S242, a fatal neonatal meningitis Escherichia coli strain belonging to the worldwide-distributed O25b:H4-ST131 clone that produces extended-spectrum beta-lactamase CTX-M-15. A lytic phage, EC200 PP , active against S242, was isolated from environmental water. After determining in vitro and ex vivo stabilities and pharmacokinetic properties of EC200 PP in rat pups, we assessed the therapeutic efficacy of a single dose of 10 8 PFU using models of sepsis and meningitis in which fatality was 100%. EC200 PP was partially neutralized by human serum. In contrast to the high concentration of phage in the spleen and the kidney, low titers in urine and the central nervous system were observed. Nevertheless, in the sepsis model, EC200 PP administered 7 h or 24 h postinfection resulted in 100% and 50% pup survival, respectively. In the meningitis model, EC200PP administered 1 h or 7 h postinfection rescued 100% of the animals. The most delayed treatments were associated with the selection of phage-resistant S242 mutants. However, a representative mutant was highly sensitive to killing serum activity and avirulent in an animal model. EC200PP is a potential therapeutic agent for sepsis and meningitis caused by the widespread E. coli O25:H4-ST131 multidrug-resistant clone.

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Section: Methodsmentioning

confidence: 99%

“…After solidification, 2 ϫ 10 6 PFU of bacteriophage stock suspensions was spotted on plates carrying each bacterial strain. After adsorption of the spots, the plates were inverted and incubated for 24 h at 37°C before the degree of lysis was scored (37,46).…”

Section: Methodsmentioning

confidence: 99%

Efficacy of Bacteriophage Therapy in Experimental Sepsis and Meningitis Caused by a Clone O25b:H4-ST131 Escherichia coli Strain Producing CTX-M-15

Pouillot

Chomton

Blois

et al. 2012

Antimicrob Agents Chemother

122

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“…Susceptibility to phages was tested by spotting 10 7 plaque-forming-units (PFU) onto the bacterial lawn. After allowing 20 min for the spots to be absorbed, the plates were inverted and incubated for 24 h at 37°C before recording the lysis stage (22,32). Clear lysis zones were recorded as "ϩ", whereas turbid zones reflecting low level of bacterial death were recorded as "ϩ/ Ϫ".…”

Section: Methodsmentioning

confidence: 99%

Rapid Identification of International Multidrug-Resistant Pseudomonas aeruginosa Clones by Multiple-Locus Variable Number of Tandem Repeats Analysis and Investigation of Their Susceptibility to Lytic Bacteriophages

Larché

Pouillot

Essoh

et al. 2012

Antimicrob Agents Chemother

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The objective of this study was to determine the genetic diversity of multidrug-resistant (MDR) Pseudomonas aeruginosa strains isolated over a period of 12 months in two French hospitals and to test their susceptibility to bacteriophages. A total of 47 MDR isolates recovered from hospitalized patients were genotyped using multiple-locus variable number of tandem repeats analysis. The genotypes were distributed into five clones (including 19, 5, 5, 3, and 3 isolates, respectively) and 12 singletons. Comparison to 77 MDR strains from three other countries, and MLST analysis of selected isolates showed the predominance of international MDR clones. The larger clone, CC235, contained 59 isolates displaying different antibiotic resistance mechanisms, including the presence of the GES1, VIM-2, VIM-4, and IMP-1 ␤-lactamases. Three newly isolated P. aeruginosa bacteriophages were found to lyse 42 of the 44 analyzed strains, distributed into the different clonal complexes. This pilot study suggests that systematic genotyping of P. aeruginosa MDR strains could improve our epidemiological understanding of transmission at both the local (hospital) and the national level and that phage therapy could be an alternative or a complementary treatment to antibiotics for treating MDR-infected patients.

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“…High titre (lOll/ml.) phage stocks were prepared by a modification of a procedure described by Postic & Finland (1961). Tubes of melted semi-solid agar after seeding with 1000-5000 phage particles and the indicator strain of bacterium were poured onto Petri plates previously layered with 3-4 ml.…”

Section: Mediamentioning

confidence: 99%