Bipolar Gram Negative Rods Klebsiella pneumoniae, Klebsiella oxytoca, Pasteurella mutocida

www.microbiologyinpictures.com Klebsiella pneumoniae is a bipolar gram negative rod. K. pneumoniae has a polysaccharide capsule that will make the colonies look mucoid. The five tube test can be used to indentify K. pneumonia. The TSI tube should be acid over acid with no hydrogen sulfide production. Lysine deaminase should be negative, motility should be negative, ornithine decarboxylase should be negative and urea should be positive. K. pneumoniae can cause a nosocomial infection, frequently lower respiratory tract infections. K. pneumonia can also cause wound infections, urinary tract infections and bacteremia.

Gram Positive Cocci in Chains Streptococcus pyogenes, Streptococcus mitans group, Entrococcus faecalis

www.microbiologyinpictures.com Streptococcus pyogenes are gram posistive cocci in chains or pairs. S. pyogenes is small, transparent, smooth and beta hemolytic. S. pyogenes can be confirmed with a positive PYR or bacitracin test. S. pyogenes can cause a host of diseases from sore throat to skin infections to toxic shock syndrome. One of the main diseases associated with S. pyogenes is strep throat. While S. pyogenes only cause’s one third of the strep throat cases, S. pyogenes is the only thing that laboratory technicians look for when strep throat is suspected.

Gram Positive Cocci in Clusters Staphlycoccus aureus, Staphyloccous saprophyticus, Staphylococcus epidermidis

www.mmic-tp.blogspot.com Staphlycoccus saprophyticus are gram positive cocci in clusters. S. saprophyticus is white to cream colored, big and non-hemolytic. S. saprophyticus is resistance to novobiacin and can be confirmed with a novobiacin disk with a zone size less then 16mm. S. saprophyticus is normally a non-clinically significant organism but can cause urinary tract infections in young sexually active females.

Gram Positive Cocci in Pairs Streptococcus agalactiae, Streptococcus anginosus, Enterococcus facium

www.microbiologyinpictures.com S. agalactiae are gram positive cocci in pairs or chains. S. agalactiae are grayish/white, mucoid with a small zone of beta hemolysis. S. agalactiae can be confirmed with the Lancefield antigen typing or with a hippurate hydrolysis disk test. S. agalactiae can cause neonatal group B disease in an early and late onset form. Ten to thirty percent of women has S. agalactiae as normal flora and can pass the organism to the newborn in the birth canal; this is the early onset form of neonatal group B disease. The early onset form presents symptoms of meningitis and pneumonia with bacteremia within the first 2 days of life and has a high mortality rate. Late onset occurs within a week and is not associated with the mother having S. agalactiae. Meningitis is the only symptom associated with late onset form and the mortality rate is lower though still significant. S. agalactiae can also cause wound infections.

Gram Positive diplococci in lancet shape Streptococcus pneumoniae

www.microbiologyinpictures.com S. pneumoniae is a gram positive diplococcic in lancet shape or chains. S. pneumoniae colonies will be alpha hemolytic, translucent, mucoid, glistening and have a dime shape. S. pneumoniae can be confirmed with the optichin (P) disk test with a zone size ≥15mm. S. pneumoniae is the most common cause of otitis media (ear infections) in children 3 and under. S. pneumoniae can also cause sinusitis, arthritis and is the number one cause of bacterial pneumonia. Bacterial meningitis can follow a S. pneumonia infection.