It is part of what sees us through bacterial pneumonia, or pyelonephritis, or cellulitis.

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Infrequently, bronchiolitis is accompanied by another lung infection such as bacterial pneumonia, which is treated separately.

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After ten days on a ventilator, six per cent develop bacterial pneumonia, resulting in death forty to fifty-five per cent of the time.

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Medical historians believe that a large proportion of those who died of the Spanish flu pandemic in 1918 were not killed by the flu virus, but by secondary bacterial pneumonia, which was difficult to treat before the introduction of antibiotics.

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Since 1928 doctors have used more than 80 antibiotics to treat bacterial infections such as pneumonia, ear infections and tuberculosis.

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Danger arises when the virus leads to bacterial respiratory infections, triggering conditions such as pneumonia, says Edward Dubovi, director of virology at Cornell University's Animal Health Diagnostic Center.

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