Streptococcus agalactiae –Only species that carries the group B antigen. –Initially recognized to cause puerperal sepsis (childbed fever ) Now this is uncommon –Septicemia, pneumonia, and meningitis in newborns –Other infections (Box 23-3)

Streptococcus agalactiae Physiology and Structure –Gram (+) streptococci –Facultative anaerobe –β –hemolytic (1-2% are nonhemolytic) –Classified by B antigen

Streptococcus agalactiae Epidemiology –Site of colonization: Lower gastrointestinal tract Genitourinary tract –10% to 30% of pregnant women are carriers. –60% of infants born to colonized mothers become infected with mothers’ organisms. This can lead to pneumonia, bacteremia, and meningitis

Streptococcus agalactiae Epidemiology cont. –Infections in men and non-pregnant women: Primarily skin and soft-tissue Bacteremia Urosepsis (UTI with bacteremia) Pneumonia

Streptococcus agalactiae Epidemiology cont. –Conditions that predispose disease in adults: Diabetes mellitus Cancer Alcoholism

Streptococcus agalactiae Clinical Diseases –Early-Onset Neonatal Disease Disease acquired in utero or at birth, symptoms appear within the first week of life. Diseases: –Bactermia –Pneumonia –Meningitis Pulmonary problems observed in most infants Meningeal involvement may be non- apparent at first –CSF examination is a must

Streptococcus agalactiae 5% mortality rate 15% to 30% of meningitis survivors have neurological problems including: –Blindness –Deafness –Severe mental retardation –Late-Onset (1 week to 3 months) Source of disease: –Mother –Other infants Bacteremia with meningitis

Streptococcus agalactiae Clinical Diseases cont. –P–Pregnant women – UTI’s –I–Infections in Men and Non-pregnant women Generally older and/or compromised immunity Common infections –B–Bacteremia –P–Pneumonia –B–Bone and joint infections –S–Skin and soft-tissue infections Mortality is higher in this group 15% to 32%.

Diagnosis –Culturing –Antigen Detection –DNA (PCR) test Treatment –Penicillin G –Pregnant women are give IV 4 hours before delivery

Viridans Streptococci Viridans –Heterogeneous collection of α- hemolytic and nonhemolytic streptococci –Name Viridis is Latin for “green” –20 species identified and placed in 6 groups Table 23-5 –Viridans cultures: Require complex media Supplemented with blood products Incubation in 5% to 10% CO 2

Viridans Streptococci Viridans –Colonization Oropharynx Gastrointestinal tract Genitourinary tract Rarely found on skin –Sebum is toxic to viridans –Common infections Dental caries Subacute endocarditis –

Viridans Streptococci Viridans –Common infections cont. Suppurative intraabdominal infections –Prevention and Control Susceptible to Penicillin, (most strains) Moderately and highly resistant strains have become more common