Bergey's Manual of Determinative Bacteriology

Identification flow charts 

Bergey’s Manual of Determinative Bacteriology 

All of the unknowns will fall into the following groups in Bergey's Manual of Determinative 

Bacteriology (The pink book on the shelf in the laboratory). 

GROUP 4 

Description: Gram Negative, Aerobic/Microaerophilic rods and cocci 

Key differences are: pigments/fluorescent, motility, growth requirements, denitrification, 

morphology, and oxidase, read Genera descriptions 

Examples: Acinetobacter, Pseudomonas, Beijerinckia, Acetobacter 

GROUP 5 

Description: Facultatively Anaerobic Gram negative rods 

Key differences are: growth factors, morph., gram rxn., oxidase rxn., read Genera descriptions 

Examples: Family Enterobacteriaceae and Vibrionaceae 

GROUP 17 

Description: Gram-Positive Cocci 

Key differences are: oxygen requirements, morph., growth requirements (45°C and supplements), 

read Genera descriptions 

Examples: Micrococcus, Staphylococcus, Streptococcus, Enterococcus, Lactococcus, Aerococcus 

GROUP 18 

Description: Endospore-Forming Gram positive rods and cocci 

Key differences are: oxygen requirements, motility, morph, catalase 

Examples: Bacillus, Clostridium 

GROUP 19 

Description: Regular, Nonsporlating Gram positive rods 

Key differences are: morph., oxygen require, catalase 

Examples: Lactobacillus, Listeria 

GROUP 20 

Description: Irregular, Nonsporlating Gram-positive rods 

Key differences are: catalase, motility, morph., read Genera descriptions 

Examples: Actinomyces, Corynebacterium, Arthrobacter, Propionibacterium 

GROUP 21 

Description: Weakly Gram-Positive Nonsporlating Acid Fast Slender Rods 

Key differences are: acid fast, growth 

Examples: Mycobacterium 

1


Differentiation via Gram stains and cell morphology. 

Gram Stain & Morphological 

Flowchart 

Some Examples 

Gram Positive 

Cocci 

Bacilli 

Filamentous 

Round in clusters 

& tetrads: 

Staphylococcus 

Micrococcus 

Peptococcus 

Oval shape in 

Chains: 

Streptococcus 

Peptostreptococcus 

Enterococcus 

Club-shaped and/or in 

palisades: 

Corynebacterium 

Listeria 

Erysipelothrix 

Mycobacterium (Acid Fast) 

Propionobacterium 

Spore-bearing, 

large, uniform: 

Bacillus 

Clostridium 

Extensive 

branching: 

Actinomyces 

Arachnia 

Nocardia (partially 

acid-fast) 

Streptomyces 

Branching rudimentry 

or absent: 

Erysipelothrix 

Lactobacillus 

Eubacterium 

Gram Negative 

Cocci 

Bacilli 

Neisseria 

Veillonella 

Medium-sized 

cocco-bacillary: 

Acinetobacter 

Moraxella 

Tiny-coccobacillary: 

Brucella 

Bordetella 

Bacteroides 

Pleomorphic 

coccobacillary 

& filamentous: 

Haemophilus 

Bacteroides 

Pasteurella 

Francisella 

Actinobacillus 

Eikenella 

Cardiobacterium 

Flavobacterium 

Exaggerated 

pointed ends: 

Fusobacterium 

nucleatum 

Coiled & 

sphero-plastic: 

Streptobacillus 

Fusobacterium 

Curved, 

comma-shaped: 

Vibrio 

Campylobacter 

Spirillium 

Uniformly 

Bacillary: 

Enterobacteriaceae 

Pseudomonas 

Aeromonas 

Alcaligenes 

Chromobacterium 

2


Gram Positive Rods ID Flowchart 

Gram Positive Rods 

Bacillus spp. 

Clostrididium spp. 

Corynebacterium spp. 

Lactobacillus spp. 

Mycobacterium spp. 

Spore Forming 

+ - 

Mycobacterium smegmatis 

+ 

Bacillus spp. 

Clostridium spp 



Mycobacterium spp. 

Acid Fast 

- 

Strict Anaerobes 

Corynebacterium spp 


+ 

- 

Clostridium spp. 

You sure you have this? 

Go to Bergey's. 

Bacillus spp. 

See separate flowchart. 

Catalase 

+ 


- 


Starch Hydrolysis 

Glucose Ferm. Activity 

+ 

- 

Corynebacterium kutsceri 

Corynebacterium xerosis 

Acid & Gas 

Acid 

Lactobacillus fermenti 

Lactobacillus casei 

Lactobacillus delbrueckii 

Mannitol 

+ 

Lactobacillus casei 

Lactobacillus delbrueckii 

- 

3


B. subtilis 

B. cereus 

B. megaterium 

B. stearothermophilus 

B. polymyxa 

B. mycoides 

B. macerans 

B. thuringiensis 

B. macquariensis 

B. licheniformis 

B. lentus 

B. alvei 

B. anthracis 

B. alcalophilus 

B. coagulans 

B. brevis 

B. circulans 

B. firmus 

B. pantothenticus 

B. anthracis 

(non-motile) 


(makes insecticidal 

protein) 

B. mycoides 

(colony has a 

rhizoidal appearance) 

B. cereus 

(Motile - It is this 

one ) 

+ 

Cell Diamenter ! 1"m 

(the width) 

+ 

B. subtilis 

B. cereus 

B. polymyxa 

B. mycoides 



B. alvei 

B. anthracis 

B. coagulans 

B. subtilis 

B. polymyxa 

B. lichenifomis 

B. alvei 

B. coagulans 

Bacillus spp. ID Flowchart 

Starch Hydrolysis 

(amylase) 

VP 

(add creatine as catalyst 

w/ reagents) 

+ 

Bacillus spp. 

B. megaterium 


B. macerans 



B. lentus 


B. badius 

B. brevis 

B. circulans 

Swollen Cell 

(containing spore) 

- + 

- 

- 


(growth at 55°C-rest neg.) 

B. macerans 



B. lentus 

(catalase neg.-rest pos.) 


B. brevis 

B. circulans 

- 

B. pumilus 

(VP is pos., rest are neg.) 

B. marinus 

B. sphaericus 

B. schlegelii 

(grows at 55°C, rest no) 

B. popilliae 

B. pasteurii 

B. lentimorbus 

B. azotoformans 

B. badius 

B. insolitus 

B. larvae 

B. laterosporus 

B. badius 

(spore is not 

round, rest are) 

B. insolitus 


B. pasteurii 

B. marinus 

B. sphaericus 

B. megaterium 

(citrate pos.) 

B. badius 

(citrate neg.) 

+ + 

Catalase 


+ 

B. sphaericus 

B. pasteurii 


(oval spore, 

rest are round) 

- 


B. larvae 

B. pasteurii 

(round spore, rest 

are oval) 

B. popilliae 

Citrate 

B. larvae 

(gelatinase pos.) 

B. popilliae 

(gelatinase neg.) 

Swollen Cell 

(containing spore) 

- 

B. insolitus 

(acid from glucose) 

B. marinus 

(acid from glucose) 

Nitrate Reduction 

- 

+ 

B. coagulans 


B. subtilis 

Citrate 

- 

B. polymyxa 

(manitol pos.) 

B. alvei 

(manitol neg.) 

6.5% NaCl Growth 

+ 

B. macerans 



B. brevis 

B. circulans 

- 


(acid via arabinose neg.) 

B. circulans 

(acid via arabinose pos.) 

+ 

B. pasteurii B. sphaericus 

- 

6.5% NaCl Growth 

+ 

B. subtilis 

(no growth at 55°C) 


(growth at 55°C) 

- 

B. coagulans 

Acid from Arabinose 

- 


(methyl red pos.) 

B. brevis 

(methyl red neg.) 

+ 

B. macerans 

(gas from glucose pos.) 


(gas from glucose neg., 

no growth < pH 7.0) 

B. circulans 

(gas from glucose neg., 

growth < pH 7.0) 

4


Gram Positive Cocci ID Flowchart 

Gram Positive Cocci 

+ 

Micrococcus spp. 

Staphylococcus spp. 



Streptococcus spp. 

Enterococcus spp. 

Catalase 

- 

Streptococcus pneumoniae 

Streptococcus mitis 

Streptococcus pyogenes Group A 

Streptococcus spp. Group B 



Bile Esculin 

(growth with esculin hydrolysis) 

Gamma (!) 

- 




(see Bergey’s) 

+ 

Enterococcus faecalis 

Enterococcus faecium 

Enterococcus hirae 

Enterococcus mundtii 

Growth w/ Tellurite 

+ 

Staphylococcus aureus 


Mannitol Fermentation 

+ 



Yellow Pigment (Colony) 


- 

- 

Hemolysis 

Alpha (#) 

Enterococcus faecalis 

Beta (") 

+ 



Enterococcus faecium 

(mannitol pos., white colony) 

Enterococcus hirae 

(mannitol neg.) 

Enterococcus mundtii 

(mannitol pos., yellow colony) 

- 

Glucose Fermentation 

Novobiocin Sensitivity 



Pyrrolidonearylamidase 

(PYR Test) 

+ 

Micrococcus varians 

Yes 

Staphylococcus epidermidis 

- - 

No 

Micrococcus luteus Staphylococcus saprophyticus 

+ 



(Streptococcus agalactiae) 

- 

Optochin Sensitivity 

Yes 


No 


5


Gram Negative Rods ID Flowchart 

Gram Negative Rods 

+ 

Aeromonas, Pseudomonas, Vibrio 

Oxidase Test 

- 

Enterobacteriaceae 

(See Separate Flowchartt) 

Vibrio spp., Aeromonas spp. 

+ Acid - Acid 

Glucose Fermentation 

Pseudomonas spp. 

Na+ Required for Growth 

- 

Aeromonas spp. 

Fluorescent Diffusible Yellow Pigment 

(Fluorescein)—use Psuedo F Agar 

+ 

Vibrio spp. 

+ 

V. fischeri 

V. logei 

V. orientalis 

V. splendidius 

Luminescent 

- 

Other Vibrio spp. 

(See Bergey's) 

+ 

A. hydrophila 

A. salmonicida 

(subsp. masoucida) 

A. sobria 

(no gas from glucose) 

A. veronii 

VP 

Other Aeromonas spp. 


Motility 

- 

+ 

P. aeruginosa 

P. chlororaphis 

P. cichorii 

P. fluorescens 

P. putida 

P. syringae 

(Oxidase Neg.) 

Other Pseudomonas spp. 


Non-Fluorescent Diffusible Blue Pigment 

(Pyocyanin)—use Psuedo P Agar 

- 

Pigment 

(Yellow Colony) 

+ 

A. hydrophila 

A. veronii 

- 

A. salmonicida 

(subsp. masoucida) 

- 


P. cichorii 


P. putida 

P. syringae 

+ 

P. aeruginosa 

+ 

- 

V. fischeri 

V. logei 

V. orientalis 


H 2 S Production 

Nitrate Reduction 

+ 

- 

A. hydrophila A. veronii 

30°C Growth 37°C Growth 

+ + 

V. fischeri - V. orientalis - 

V. logei 


+ 


(Colony Pigmented) 


(To differentiate Biovars 

do a lecithinase test) 

- 

P. putida 

(Lecithinase Neg.) 

P. syringae 

(Oxidase Neg.) 

P. cichorii 

(Lecithinase Pos.) 

6


Family Enterobacteriaceae Lactose Positive ID Flowchart 

Family Enterobacteriaceae 

Lactose Fermentation 

+ - 

Citrobacter diversus 

Citrobacter freundii 

Enterobacter aerogenes 

Enterobacter cloacae 

Enterobacter amnigenus 

Enterobacter intermedius 

Erwinia carotovora 

Erwinia chrysanthemi 

Escherichia coli 

Klebsiella oxytoca 

Klebsiella pneumoniae 

(subsp. ozaenae and pneumoniae) 

Serratia fonticola 

Serratia rubidaea 

See Lactose Negative Flowchart 

for Enterobacteriaceae 

Indole 

- 

+ 

The Rest 





Citrate 

+/+ 

Enterobacter intermedius 

+/- 

MR-VP 




(subsp. ozaenae) 

-/+ 


(subsp. pneumoniae) 






Lysine Decarboxylase 

+ 


(VP neg.) 


(VP and H 2 S pos.) 


(VP pos and H 2 S neg.) 

- 


H 2 S Production 

+ 

Klebsiella pneumoniae subsp. pneumoniae 

Non-motile, No Pigment 


Motile, Red pigment 


Motile, No pigment 


Acid from sorbitol 


No acid from sorbitol 

- 

?? 

+ 


- 


Motility pos. 

Klebsiella pneumoniae subsp. ozaenae 

Motility neg. 


Lysine unknown but Gelatinase 

positive; none above are positive. 

7


Family Enterobacteriaceae Lactose Negative ID Flowchart 

Edwardsiella tarda 

Erwinia cacticida 

Morganella morganii 

Proteus mirabilis 

Proteus penneri 

Proteus vulgaris 

Providencia stuartii 

Salmonella bongori 

Salmonella enterica 

Family Enterobacteriaceae Continued 

Lactose Negative Flow Chart 

Serratia marcescens 

Serratia liquefaciens 

Shigella spp. (boydii, dysenteriae, flexneri) 

Shigella sonnei 

Yersinia enterocolitica 

Yersinia pestis 

Yersinia pseudotuberculosis 

- 















+ 

?? 

Indole Test 

Urease 

+ - 

H 2 S 

Please See Bergey’s to ID: 

Shigella spp. 

(boydii, dysenteriae, flexneri) 

Yersinia enterocolitica 


Ornithine decarb. pos. 


Ornithine decarb. neg., motile 


Ornithine decarb. neg., non-motile 








+ 

- 





+ 

Motility 

- 

Urease 

Ornithine Decarboxylase 

+ + 



- 

- 




(lysine decarb. neg., the rest pos.) 





H 2 S 



Ornithine Decarboxylase 

+ 

+ 


KCN growth pos. 


KCN growth neg. 

(It is this one) 


Red pigment 


No Red pigment 

- 


- 


8

Bergey's Manual of Determinative Bacteriology

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