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.
Antibiotics are grouped into families of similar types. Bacteria also are put together in groups of similar types, such as streptococcus or E. coli. Certain types of bacteria are especially susceptible to particular classes of antibiotics. Treatment can be targeted more precisely if your doctor knows what type of bacteria you're fighting. Antibiotics are usually reserved for bacterial infections, because these types of drugs have no effect on illnesses caused by viruses. But sometimes it's difficult to tell which type of germ is at work.