Do Primocolonizing Bacteria Enable Bacteroides thetaiotaomicron Intestinal Colonization Independently of the Capacity To Consume Oxygen?

Aerobic bacteria are frequent primocolonizers of the human naive intestine. Their generally accepted role is to eliminate oxygen, which would allow colonization by anaerobes that subsequently dominate bacterial gut populations. In this hypothesis-based study, we revisited this dogma experimentally in a germfree mouse model as a mimic of the germfree newborn.

Clinical Relevance of Type II Fatty Acid Synthesis Bypass in Staphylococcus aureus.

The need for new antimicrobials to treat bacterial infections has led to the use of type II fatty acid synthesis (FASII) enzymes as front-line targets. However, recent studies suggest that FASII inhibitors may not work against the opportunist pathogen , as environmental fatty acids favor emergence of multi-anti-FASII resistance. As fatty acids are abundant in the host and one FASII inhibitor, triclosan, is widespread, we investigated whether fatty acid pools impact resistance in clinical and veterinary isolates.

Activation of the cryptic PhnE permease promotes rapid adaptive evolution in a population of Escherichia coli K-12 starved for phosphate.

Escherichia coli K-12 suffers acetic acid stress during prolonged incubation in glucose minimal medium containing a limiting concentration of inorganic phosphate (0.1 mM P(i)), which decreases the number of viable cells from 6 × 10(8) to ≤10 CFU/ml between days 6 and 14 of incubation. Here we show that following two serial transfers into P(i)-limiting medium, evolved mutants survived prolonged incubation (≈10(7) CFU/ml on day 14 of incubation).

Fur-dependent detoxification of organic acids by rpoS mutants during prolonged incubation under aerobic, phosphate starvation conditions.

The activity of amino acid-dependent acid resistance systems allows Escherichia coli to survive during prolonged incubation under phosphate (P(i)) starvation conditions. We show in this work that rpoS-null mutants incubated in the absence of any amino acid survived during prolonged incubation under aerobic, P(i) starvation conditions. Whereas rpoS(+) cells incubated with glutamate excreted high levels of acetate, rpoS mutants grew on acetic acid.