mls micro exam 3

Neisseria gonorrhoeae CTA sugar

Glucose positive, maltose lactose and sucrose negative

Neisseria gonnorrhoeae growth requirements

Requires CO2

Neisseria gonnorrhoeae specimen collection

Environmentally fragile and requires charcoal or another supplement

Neisseria gonorrhoeae media

Chocolate agar, selective media: thayer martin, new york city, martin lewis

Neisseria gonorrhoeae complications

Sexually transmitted infections: acute urethritis in males, cervicitis in females, throat and rectal infections. Gonococcal eye infections in newborns, septicemia, septic arthritis

Enterobacteriaceae gram stain

Short, fat, non-spore forming gram negative rods

Enterobacteriaceae Growth requirements

Facultative anaerobes

Enterobacteriaceae normal flora

Normal inhabitants of the intestinal tract of humans

Enterobacteriaceae Biochemical results

All ferment glucose, all oxidase negative, all reduce nitrate to nitrite, all are motile except Shigella, Klebsiella, and Yersina. All grow well on routine media: BAP- large, grey, may be beta hemolytic, Choch- large grey, MAC- pink LF to colorless NLF, HEK- orange to clear, some with black centers

IMVIC

Indole, methyl red, voges proskauer, and citrate

Escherichia

MAC- pink, flat colonies LF, HEK- orange, flat colonies LF, BAP beta hemolytic, IMVIC =++==, TSI A/AG, LIA K/A

Edwardsiellae

MAC- clear flat NLF, HEK- black colonies (H2S), IMVIC ++==, TSI K/AG H2S, LIA K/K H2S

Salmonellae

MAC- NLF, HEK- black colonies H2S, IMVIC =+=+, TSI K/AG H2S, LIA K/K H2S

Citrobacteriaceae

MAC- NLF or LF, HEK- LF black center, IMVIC =+=+, TSI A/AG H2S, LIA K/A H2S

Klebsiellae

MAC- large mucoid LF, HEK- large mucoid LF, TSI A/AG, LIA K/K, ornithine decarboxylase =

Klebsiella pneumoniae

Indole negative, IMVIC ==++

Klebsiella oxytoca

Indole positive, IMVIC +=++

Proteae

Highly motile; swarms across plates. NLF on Mac and Hek. Tsi k/ag h2s variable, lia k/a h2s

Proteae vulgaris

Indole positive and ornithine negative. IMVIC ++==

Proteae mirabilis

Indole negative and ornithine positive. IMVIC =+=+

Yersiniae

Mac- NLF, Hek- NLF, IMVIC =+==, Tsi a/a, lia a/a

Non-fermenters

Strict aerobe, non-spore forming, gram negative rods. Utilizes carbohydrates through oxidative pathway- glucose oxidizers. identification is difficult- slow growers and weak reactions. Tsi k/k, oxidase positive, mac- nlf or no growth, oxidizes OF glucose, motility mostly positive

Pseudomonas aeruginosa

A non fermenter, BAP- flat, irregular edge, grey green with silver sheen, beta hemolytic, may be muccoid. odor: corn tortillas or over ripe grapes.

Pseudomonas biochemical tests

Mac- flat NLF, oxidase positive, tsi k/k silver sheen, motility positive top layer, OF glucose positive, tech agar- blue green pigment pyocyanin, growth at 42 degrees celsius

Pseudomonas antibiotics

Extremely resistant to most antibiotics, sensitive to amino glycosides, colistin, meropenem, 3rd gen cephalosporins, piperacillin. Newer antibiotic is ceftazidime/avibactam. Resistant to penicicllin/ampicillin, 1st generation cephalosporins

Urine culture pathogenic organisms

E. coli, klebsiella, staph saprophyticus, p. mirabilis, pseudomonas aeruginosa, enterococci

Urine culture common contaminants

Coag negative staph, corynebacterium sp., lactobacillus species, streptococcus viridans, diptheroid and gardnerella vaginalis

Urine culture CCMS

Clean catch midstream- most common and may contain urogenital flora- when the patient collects sample themself

Urine culture catheterized

Sterile but can be contaminated with urogenital flora

Urine culture suprapubic aspiration

Most sterile way of collection, usually used on babies and is anaerobic

Urine culture quantitation 1 ml loop

colony count x 1,000 = cfu/ml

Urine culture quantitation 10ml loop

colony count x 100 = cfu/ml

Urine culture normal flora

There is growth of more than 3 organisms for the genital tract origin, one or two present with each less than 10,000 cfu/ml. more than 50,000 cfu/ml is pathogenic.

Urine culture pathogen

There is one organism above 10,000 cfu/ml, there are two organisms with one above 50,000 cfu/ml and one between 10-50000 cfu/ml

Greater than 100,000 cfu/ml

Threshold for diagnosing a uti in asymptomatic patients

10-100,000 cfu/ml

Indicate infection in symptomatic patients

Urinalysis

Positive blood and leukocyte esterase. Nitrite positive for bacteria who can reduce nitrate to nitrite. Look for RBC, WBC and bacteria under microscope

Salmonella O antigen

Somatic antigen

Salmonella H antigen

Flagellar antigen

Salmonella Vi antigen

Capsular antigen- present in Salmonella typhi

Salmonella diseases

Typhoid or enteric fever. Gastroenteritis, bacteremia and septicemia

Shigella O antigen

Somatic antigen

Shigella diseases

Bacillary dysentery, hemolytic uremic syndrome (HUS)

Shigella gp. A serogroup

Shigella dysenteriae

Shigella gp. B serogroup

Shigella flexneri

Shigella gp. C serogroup

Shigella boydii

Shigella gp. D serogroup

Shigella sonnei

Salmonella colony morphology

Mac- NLF, HEK- NLF with H2S center

Salmonella biochemical tests

IMVIC =+=+, tsi k/ag h2s, lia k/kg h2s, urease negative, oxidase negative, motility positive

Shigella colony morphology

Mac- NLF, Hek- NLF

Shigella biochemical tests

IMVIC =+==, tsi k/a, lia k/a, urease negative, oxidase negative, motility negative

Campylobacter culture set up

Campy CVA placed in campy jar with campy gas pack (microaerophilic) and incubated at 42 degrees celsius.

Campylobacter colony growth on campy cva 

Small, flat, watery colony with pink tinge

Streptococcus pyogenes biochemical tests

gram positive cocci in chains, catalase negative, pyr positive, a disc sensitive, latex agglutination

Streptococcus pyogenes diseases

Rheumatic fever, scarlet fever, pharyngitis, glomerulonephritis, pyogenic infections

Streptococcus pyogenes colony morphology

Pinpoint colonies, grey-white or colorless, beta hemolytic

Streptococcus agalactiae biochemical tests

Gram positive cocci chains, catalase negative, bacitracin resistant, pyr negative, camp positive, hippurate positive

Streptococcus agalactiae diseases

Caused by vertical transmission of the organism from the mother

Streptococcus agalactiae colony morphology

Milky white colonies, medium size, small zone of beta hemolysis

Streptococcus pneumoniae diseases

Pneumonia, sinusitis, otitis media, bacteremia, meningitis, bronchitis, peritonitis

Streptococcus pneumoniae biochemical tests

Catalase negative, p disc susceptible, bile solubility positive, latex agglutination

Streptococcus pneumoniae gram stain result

Gram positive cocci pairs- lancet shaped. Many PMN, capsule evident by clear zone around organism

Streptococcus pneumoniae colony morphology

Flat, alpha hemolytic dimpled center

Enterococcus biochemical tests

Gram positive cocci pairs/short chains, catalase false positive, pyr positive, esculin positive, lap positive if alpha, a and p disc resistant, could be beta alpha or gamma hemolytic, able to grow in NaCl

Strep grp D non enterococcus biochemical tests

Pyr negative, non hemolytic, the rest is the same as enterococcus.

Enterococcus diseases

UTI’s, bacteremia, endocarditis

Normal genital flora organisms

Lactobacillus sp., corynebacterium sp., coag neg staph, gardnerella vaginalis, enterococcus sp., streptococcus sp.