STREPTOCOCCI :
GROUPS A & B

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StreptococcalAny of a group of Gram-positive bacteria, genus Streptococcus, some of which cause disease. Streptococci are spherical and divide by fission, but they remain attached and so grow in beadlike chains. The incidence and severity of streptococcal diseases decreased dramatically after the introduction of antibiotics, (penicillin, erythromycin, and selected cephalosporins). All were effective against the organisms, but the medical community was shaken by the arrival in the late 1980s of several severe forms of streptococcal infection and by the emergence of several drug-resistant strains. This month your Bug of the Month will report on the two types of strep most associated with disease, Group A and B.
Streptococcus Group AStreptococcal (strep) infections are caused by group A streptococcus, a bacterium responsible for a variety of health problems. These infections can range from mild skin infection or sore throat to severe, life-threatening conditions such as toxic shock syndrome (multi-organ failures) and necrotizing fasciitis (soft tissue disease), commonly known as flesh eating disease. Most people are familiar with strep throat, which along with minor skin infection, is the most common form of the disease. In addition to step throat and superficial skin infections, group A strep bacteria can cause infections in tissues at specific body sites, including lungs, bones, spinal cord, and abdomen. Health experts estimate that more than 10 million mild infections (throat and skin) like these occur every year.


EPIDEMIOLOGY

RESERVOIR
Humans.

MODE OF TRANSMISSION

These bacteria are primarily transmitted via large respiratory droplets or by direct contact with patients or carriers, and only rarely by indirect contact through objects or casual contact.

In populations where impetigo is prevalent, Group A strep may be recovered from normal skin 1-2 weeks before skin lesions develop.

Anal, vaginal, skin and pharyngeal carriers of Group A strep have been responsible for nosocomial outbreaks of infection following surgical procedures. These infections have been traced to operating room personnel who were carriers.

Explosive outbreaks of Group A strep sore throat may follow ingestion of contaminated food such as milk and milk products. Group A strep may be transmitted to cattle from human carriers, and then spread through raw milk. Egg salad and deviled hard-boiled eggs may also transmit Group A strep.

INCUBATION PERIOD
1-3 days

TREATMENT
Penicillin for 10 days initiated within the first 24-48 hours; erythromycin in penicillin sensitive patients; clindamycin or a cephalosporin can be used when penicillin or erythromycin are contraindicated.

Streptococcus Group BStreptococcus (GBS) is a bacterium that causes illness in newborn babies, pregnant women, the elderly, and adults with other illnesses, such as diabetes or liver disease. GBS live in the intestines of healthy persons. Few people who come in contact with a virulent strain of GBS will develop invasive GBS disease; many will have a routine throat or skin infection, and most will have no symptoms whatsoever. Although healthy people can get invasive GBS disease, those with chronic illnesses like cancer, diabetes, and kidney disease requiring dialysis and those who use medications such as steroids are at higher risk.

GBS is the most common cause of life-threatening infections in newborns. GBS is the most common cause of sepsis (blood infection) and meningitis (infection of the fluid and lining surrounding the brain) in newborns. GBS is a frequent cause of newborn pneumonia. Before prevention methods were widely used, approximately 8,000 babies in the United States would get GBS disease each year. One of every 20 babies with GBS disease dies from infection.

In pregnant women, GBS can cause bladder infections, womb infections (amnionitis, endometritis), and stillbirth.

Among men and non-pregnant women, the most common diseases caused by GBS are blood infections, skin or soft-tissue infections, and pneumonia. Approximately 20% of men and nonpregnant women with GBS disease die of the disease.



EPIDEMIOLOGY

RESERVOIR
Humans.

MODE OF TRANSMISSION

While the manner of acquisition is unclear, approximately 10-30% of pregnant woman carry GBS in the genital tract. Approximately one of every 100 to 200 babies whose mothers carry GBS develops signs and symptoms of GBS disease. Three-fourths of the cases of GBS disease among newborns occur in the first week of life ("early-onset disease"), and most of these cases are apparent a few hours after birth.

INCUBATION PERIOD
1-7 (“short onset”). In infants 1 week to several months after birth ("late-onset disease").

TREATMENT
While GBS are sensitive to penicillin G and ampicillin, some tolerant strains have been described. Severe infections should be treated with penicillin plus an aminoglycoside, preferably gentamicin.

METHODS OF CONTROL
StreptococcusDisposable gloves should be worn when contact with drainage or secretions are imminent or anticipated. Contain all secretions, dressings, gloves, etc in an impervious or leak-proof container.

Hand washing with an antiseptic or liquid soap is required.

Drainage and secretion precautions should be observed for the first 24 hours, or until adequate antibiotic therapy has been initiated. (With Group A strep infection it is important that therapy continue for at least 10 days to prevent development of rheumatic heart disease.)

Concurrent cleaning and disinfection of all surfaces with an EPA approved disinfectant effective against Streptococci. Allow for 10 minutes of disinfectant contact time.

Investigate contacts as the possible source of infection. In some states, certain Group A or B infections are reportable to the Health Department, ie: acute rheumatic heart disease/streptococcal Toxic Shock Syndrome.

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