Klebsiella aerogenes

A Gram-negative, rod-shaped bacterium. It is approximately 1-3 μm in length and motile by peritrichous flagella.
It is hemolysis negative, oxidase negative, catalase positive, indole negative, and citrate positive.

"Klebsiella" is named after German-Swiss microbiologist Edwin Klebs, and "aerogenes" means gas-producing in Latin.

It is a nosocomial and pathogenic bacterium that causes opportunistic infections (generally found in the gastrointestinal tract) including most types of infections.
The majority are sensitive to most antibiotics designed for this bacteria class, but this is complicated by their inducible resistance mechanisms, particularly lactamase, requiring a quickly change in antibiotic to avoid worsening of the sepsis.
Some infections can be caused through specific antibiotic treatments with venous catheter insertions and/or surgical procedures.
It has a short doubling time and evolution rate (mutation rate).

It is an outstanding hydrogen producer, anaerobic facultative and mesophilic (grows best in moderate temperature, from 20 to 45 oC, with the optimum growth temperature of 37 oC) bacterium.
It has high hydrogen productivity. The production is not inhibited at high hydrogen partial pressures, however, lower compared to strict anaerobes like Clostridia.

It is able to consume different sugars and in contrast to cultivation of strict anaerobes.
Owing to diverse metabolites (i.e. acids and alcohols), produced by such a strain in conjunction with its capability of utilizing different sugars, the metabolic behavior and growth can significantly vary under different conditions.