In vitro inhibition activity of different bacteriocin-producing Escherichia coli against Salmonella strains isolated from clinical cases.
OBJECTIVE
To compare in vitro the inhibitory activity of four bacteriocin-producing Escherichia coli to a well-characterized panel of Salmonella strains, recently isolated from clinical cases in Switzerland.


RESULTS
A panel of 68 nontyphoidal Salmonella strains was characterized by pulsed-field gel electrophoresis analysis and susceptibility to antibiotics. The majority of tested strains were genetically different, with 40% resistant to at least one antibiotic. E. coli Mcc24 showed highest in vitro activity against Salmonella (100%, microcin 24), followed by E. coli L1000 (94%, microcin B17), E. coli 53 (49%, colicin H) and E. coli 52 (21%, colicin G) as revealed using a cross-streak activity assay.


CONCLUSIONS
Escherichia coli Mcc24, a genetically modified organism producing microcin 24, and E. coli L1000, a natural strain isolated from human faeces carrying the mcb-operon for microcin B17-production, were the most effective strains in inhibiting in vitro both antibiotic resistant and sensitive Salmonella isolates.


CONCLUSIONS
Due to an increasing prevalence of antibiotic resistant Salmonella strains, alternative strategies to fight these foodborne pathogens are needed. E. coli L1000 appears to be a promising candidate in view of developing biotechnological alternatives to antibiotics against Salmonella infections.
Zihler
A
A
Laboratory of Food Biotechnology, Institute of Food Science and Nutrition, ETH Zurich, Zurich, Switzerland.
Le Blay
G
G
de Wouters
T
T
Lacroix
C
C
Braegger
C P
CP
Lehner
A
A
Tischler
P
P
Rattei
T
T
Hächler
H
H
Stephan
R
R
D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000494:pharmacology; D000898:Antibiosis; D015373:Bacterial Typing Techniques; D001430:Bacteriocins / Q000096:biosynthesis* / Q000494:pharmacology; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D012475:Salmonella / Q000145:classification / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D012480:Salmonella Infections / Q000382:microbiology; D013557:Switzerland
D000900:Anti-Bacterial Agents; D001430:Bacteriocins