After spending approximately 40 weeks inside the womb, the average newborn weighs 7 1/2 pounds. Most babies weigh between 5 1/2 and 10 pounds. The average length of a newborn is 20 inches (50 centimeters), with a range of 18 to 22 inches. The average head circumference (the distance around the head) is 14 inches (35 centimeters).
Lactobacillus and Bifidobacterium are the most common probiotic bacteria. The Lactobacillus genus has 18 different bacteria strains, while the Bifidobacterium genus consists of eight strains.
Proteus vulgaris. The genus Proteus is classified in the enteric bacteria, together with Escherichia coli, Salmonella, Shigella, Enterobacter and Serratia. All these bacteria are small, Gram-negative rods and are facultative anaerobes: they ferment sugars in anaerobic conditions but can use a wide range of organic molecules in aerobic conditions.