Bacterial characteristics and their culture media
Gram Reaction | Pathogenic Bacteria | Special Characteristics | Selective Culture Media |
---|---|---|---|
Gram-Positive | Staphylococcus aureus | Produces coagulase | Mannitol Salt Agar |
Streptococcus pneumoniae | Encapsulated, optochin sensitive | Blood Agar, Optochin Agar | |
Bacillus anthracis | Produces anthrax toxin, capsule | Blood Agar, MacConkey Agar | |
Clostridium difficile | Produces toxins A and B | Cycloserine-cefoxitin fructose agar (CCFA) | |
Listeria monocytogenes | Tumbling motility, cold enrichment required | Blood Agar | |
Corynebacterium diphtheriae | Produces diphtheria toxin | Loeffler's medium, Tinsdale agar | |
Enterococcus faecalis | Group D streptococcus, gamma-hemolytic | Bile Esculin Agar | |
Gram-Negative | Escherichia coli | Facultative anaerobe, lactose fermenter | MacConkey Agar, Eosin Methylene Blue (EMB) |
Salmonella enterica | Non-lactose fermenter, produces H2S | Xylose Lysine Deoxycholate (XLD) Agar | |
Pseudomonas aeruginosa | Oxidase-positive, produces pyocyanin | Cetrimide Agar, Pseudomonas Isolation Agar | |
Neisseria gonorrhoeae | Intracellular diplococci, oxidase-positive | Thayer-Martin Agar, New York City Agar | |
Klebsiella pneumoniae | Mucoid colonies, lactose fermenter | MacConkey Agar | |
Legionella pneumophila | Requires cysteine for growth, intracellular | Buffered Charcoal Yeast Extract (BCYE) Agar | |
Helicobacter pylori | Spiral-shaped, urease-positive | Skirrow's Agar, Campylobacter Blood Free Selective Agar (CCDA) | |
Vibrio cholerae | Curved, comma-shaped, produces cholera toxin | Thiosulfate Citrate Bile Salts Sucrose (TCBS) Agar | |
Shigella spp. | Non-motile, non-lactose fermenter | MacConkey Agar | |
Haemophilus influenzae | Requires factors X and V for growth | Chocolate Agar, Haemophilus Test Agar | |
Yersinia pestis | Non-motile, produces Yersinia outer proteins | Blood Agar, MacConkey Agar |
Protozoal Parasite | Detailed Characteristics | Identification |
---|---|---|
Plasmodium falciparum | Intracellular parasite causing severe malaria; multiple stages in human host | Human blood culture |
Plasmodium vivax | Forms hypnozoites (dormant stage) in the liver; relapses can occur | Human blood culture |
Plasmodium ovale | Forms dormant liver stage (hypnozoite); similar to P. vivax | Human blood culture |
Plasmodium malariae | Causes quartan malaria; distinctive 72-hour replication cycle | Human blood culture |
Giardia lamblia | Flagellated parasite causing gastrointestinal infection; forms cysts | Buffered charcoal yeast extract agar (BCYE) |
Entamoeba histolytica | Causes amoebic dysentery; forms trophozoites and cysts | Robinson's medium |
Trichomonas vaginalis | Causes sexually transmitted infection (trichomoniasis); flagellated parasite | Diamond's medium |
Toxoplasma gondii | Intracellular parasite causing toxoplasmosis; can form tissue cysts | Cell culture |
Trypanosoma cruzi | Causes Chagas disease; transmitted by triatomine bugs; intracellular parasite | LIT medium |
Leishmania spp. | Intracellular parasite causing leishmaniasis; transmitted by sandflies | NNN medium |
Cryptosporidium spp. | Intracellular parasite causing cryptosporidiosis; forms oocysts | Modified Ziehl-Neelsen (mZN) staining |
Cyclospora cayetanensis | Causes cyclosporiasis; oocyst-forming parasite; associated with contaminated food | Modified acid-fast staining |
Isospora belli | Causes isosporiasis; intracellular parasite; forms oocysts | Modified acid-fast staining |
Babesia spp. | Intraerythrocytic parasites causing babesiosis; transmitted by ticks | Human blood culture |
Naegleria fowleri | Causes primary amoebic meningoencephalitis (PAM); free-living amoeba | Non-selective culture media |
Acanthamoeba spp. | Causes Acanthamoeba keratitis and granulomatous encephalitis; free-living amoeba | Non-nutrient agar, Peptone-Yeast-Glucose (PYG) medium |
Trichomonas tenax | Found in the oral cavity; non-pathogenic flagellated parasite | Diamond's medium |
Blastocystis hominis | Causes gastrointestinal infection; unicellular parasite with diverse forms | Jones' medium |
Leishmania donovani | Causes visceral leishmaniasis; intracellular parasite; transmitted by sandflies | NNN medium |
Dientamoeba fragilis | Causes gastrointestinal infection; amoeba with no known cyst stage | Non-selective culture media |
Balantidium coli | Causes balantidiasis; ciliated parasite; forms cysts and trophozoites | Non-selective culture media |
Entamoeba coli | Commensal in the human gastrointestinal tract; non |
Classification |
Envelop |
Number of
Strands |
Family |
Species |
Shape |
Size (nm) |
Diseases
Caused |
DNA Viruses |
|||||||
Adenoviridae |
No |
Double-stranded |
Adenovirus |
Human adenovirus
(HAdV) |
Icosahedral |
70-90 |
Respiratory
infections, Conjunctivitis |
Herpesviridae |
Yes |
Double-stranded |
Herpesvirus |
Herpes simplex
virus (HSV-1, HSV-2) |
Icosahedral |
150-200 |
Cold sores,
Genital herpes |
Herpesviridae |
Yes |
Double-stranded |
Herpesvirus |
Varicella-zoster
virus (VZV) |
Icosahedral |
150-200 |
Chickenpox,
Shingles |
Herpesviridae |
Yes |
Double-stranded |
Herpesvirus |
Epstein-Barr virus
(EBV) |
Icosahedral |
150-200 |
Infectious
mononucleosis, Burkitt's lymphoma |
Papillomaviridae |
No |
Double-stranded |
Papillomavirus |
Human
papillomavirus (HPV) |
Non-enveloped |
45-55 |
Cervical cancer,
Genital warts |
Polyomaviridae |
No |
Double-stranded |
Polyomavirus |
JC virus |
Non-enveloped |
40-45 |
Progressive
multifocal leukoencephalopathy (PML) |
Polyomaviridae |
No |
Double-stranded |
Polyomavirus |
BK virus |
Non-enveloped |
40-45 |
Kidney disease,
Transplant complications |
Parvoviridae |
No |
Single-stranded |
Parvovirus |
Parvovirus B19 |
Non-enveloped |
18-26 |
Fifth disease
(Erythema infectiosum) |
RNA Viruses |
|||||||
Picornaviridae |
No |
Single-stranded |
Enterovirus |
Poliovirus |
Icosahedral |
22-30 |
Polio |
Picornaviridae |
No |
Single-stranded |
Enterovirus |
Coxsackievirus |
Icosahedral |
22-30 |
Hand, Foot, and
Mouth Disease |
Picornaviridae |
No |
Single-stranded |
Enterovirus |
Echovirus |
Icosahedral |
22-30 |
Meningitis,
Myocarditis |
Picornaviridae |
No |
Single-stranded |
Rhinovirus |
Rhinovirus |
Icosahedral |
22-30 |
Common cold |
Flaviviridae |
Yes |
Single-stranded |
Flavivirus |
Dengue virus |
Icosahedral |
40-60 |
Deng |
Group | Pathogen | Typical Characteristics |
---|---|---|
Bacteria | Escherichia coli | Gram-negative, facultative anaerobe, commonly found in the intestinal tract, can cause gastrointestinal infections, produces toxins |
Bacteria | Staphylococcus aureus | Gram-positive, facultative anaerobe, forms clusters, commonly found on the skin and mucous membranes, can cause skin infections, produces various toxins |
Bacteria | Streptococcus pyogenes | Gram-positive, facultative anaerobe, forms chains, commonly found in the throat and skin, can cause strep throat, skin infections, produces toxins |
Bacteria | Salmonella enterica | Gram-negative, facultative anaerobe, commonly found in contaminated food and water, can cause gastrointestinal infections, produces toxins |
Bacteria | Mycobacterium tuberculosis | Acid-fast staining, slow-growing, intracellular pathogen, causes tuberculosis, has a waxy cell wall, requires specialized media for culture and long incubation periods |
Bacteria | Clostridium difficile | Gram-positive, anaerobic, forms spores, commonly found in the gastrointestinal tract, can cause severe diarrhea and colitis, associated with antibiotic use, produces toxins |
Bacteria | Neisseria gonorrhoeae | Gram-negative, aerobic, diplococci, sexually transmitted pathogen, causes gonorrhea, can infect the urogenital tract and other mucous membranes, can develop resistance to antibiotics |
Bacteria | Vibrio cholerae | Gram-negative, curved rod, facultative anaerobe, commonly found in contaminated water, causes cholera, produces cholera toxin |
Bacteria | Helicobacter pylori | Gram-negative, microaerophilic, spiral-shaped, commonly found in the stomach, causes gastric ulcers and gastritis, has the ability to survive in the acidic environment of the stomach |
Bacteria | Pseudomonas aeruginosa | Gram-negative, aerobic, opportunistic pathogen, commonly found in moist environments, can cause infections in the respiratory tract, urinary tract, and wounds, produces various virulence factors |
Protozoa | Plasmodium falciparum | Intracellular parasite, causes severe malaria, undergoes complex life cycle involving human and mosquito hosts, forms different stages (merozoites, trophozoites, gametocytes) in the human host |
Protozoa | Giardia lamblia | Flagellated parasite, causes gastrointestinal infection (giardiasis), forms cysts that can survive in the environment, transmitted through contaminated water and food |
Protozoa | Entamoeba histolytica | Amoeboid parasite, causes amoebic dysentery, forms trophozoites and cysts, can invade the intestinal wall and other organs, transmitted through contaminated food and water |
Protozoa | Trichomonas vaginalis | Flagellated parasite, sexually transmitted pathogen, causes trichomoniasis, infects the urogenital tract, motile and does not form cysts |
Protozoa | Toxoplasma gondii | Intracellular parasite, causes toxoplasmosis, can form tissue cysts in various organs, transmitted through ingestion of contaminated food, can be transmitted from mother to fetus during pregnancy |
Mode of Transmission | Parasites |
---|---|
Vector-borne | Plasmodium spp. (malaria), Trypanosoma spp. (African trypanosomiasis, Chagas disease), Leishmania spp. (leishmaniasis), Borrelia burgdorferi (Lyme disease), Rickettsia spp. (Rocky Mountain spotted fever) |
Fecal-oral | Giardia lamblia, Entamoeba histolytica, Cryptosporidium spp., Cyclospora cayetanensis, Ascaris lumbricoides (ascariasis), Enterobius vermicularis (pinworm), Taenia spp. (taeniasis), Echinococcus spp. (echinococcosis) |
Sexual transmission | Trichomonas vaginalis, Human papillomavirus (HPV), Treponema pallidum (syphilis), Neisseria gonorrhoeae (gonorrhea), Chlamydia trachomatis (chlamydia) |
Direct contact | Sarcoptes scabiei (scabies), Pediculus humanus (lice infestation), Tinea spp. (ringworm), Candida spp. (yeast infection) |
Inhalation | Histoplasma capsulatum (histoplasmosis), Coccidioides spp. (coccidioidomycosis), Mycobacterium tuberculosis (tuberculosis) |
Blood transfusion | Plasmodium spp. (malaria), Trypanosoma spp. (African trypanosomiasis, Chagas disease), Babesia spp. (babesiosis), Hepatitis B virus, Hepatitis C virus, Human immunodeficiency virus (HIV) |
Organ transplantation | Trypanosoma cruzi (Chagas disease), Toxoplasma gondii, Strongyloides stercoralis (strongyloidiasis) |
Congenital transmission | Toxoplasma gondii, Treponema pallidum (syphilis), Parvovirus B19 (fifth disease), Rubella virus, Cytomegalovirus (CMV) |
Foodborne | Taenia spp. (taeniasis), Echinococcus spp. (echinococcosis), Trichinella spp. (trichinellosis), Salmonella spp., Escherichia coli (E. coli), Hepatitis A virus, Norovirus |
Waterborne | Cryptosporidium spp., Giardia lamblia, Entamoeba histolytica, Cyclospora cayetanensis, Vibrio cholerae, Salmonella spp., Leptospira spp. |
Animal bites | Rabies virus, Pasteurella multocida (from dog/cat bites) |