Corynebacterium diphtheriae (Klebs-Löffler bacillus)- An Overview

Corynebacterium diphtheriae

Habitat of Corynebacterium diphtheriae Corynebacterium diphtheriae is found in nasopharynx as well as in skin lesions, which actually represent a reservoir for the spread of diphtheria. Also found in mouth, throat, nose, skin and wound of infected person. Animals do not easily contract diphtheria. Patients carry toxigenic organism upto 3 months after infection. Morphology of Corynebacterium diphtheriae Corynebacterium diphtheriae are gram +ve rod shaped bacteria. Club shaped Irregular swelling at one end or both end gives them the “Club Shaped” appearance. Thin … Read more

Staphylococcus vs Streptococcus- 20 Major Differences

Staphylococcus and Streptococcus Differences

Staphylococcus and Streptococcus are Gram-positive and the two most common pathogenic cocci of medical importance. They are both non-motile, non-sporing, and facultative anaerobes which can be differentiated on the following grounds: S.N. Character Staphylococcus Streptococcus 1.       Cellular Arrangement Spherical cells in clusters (grape like clusters). Spherical or ovoid cells in chains or pairs. 2.       Fission/Division Irregular division in all three planes. Division in one linear direction. 3.       Catalase Test Positive (Presence of catalase enzyme) Negative 4.       Halotolerance Halotolerant. … Read more

Chlamydia trachomatis- An Overview

Chlamydia trachomatis

Habitat of Chlamydia trachomatis It is an obligate intracellular human pathogens. Humans are the only natural host. It cannot survive outside of a eukaryotic host. Chlamydia trachomatis is transmitted by oral, vaginal or anal sex, and can also be transmitted from mother to newborn during a vaginal delivery. They can cause discharge from the penis, pain and burning during urination, infection or inflammation in the ducts of testicles, and tenderness or pain in the testicles. Morphology of Chlamydia trachomatis It … Read more

Salmonellosis- Food Infection and Food Poisoning by Salmonella

Salmonellosis- Food Infection and Food Poisoning by Salmonella

What is Salmonella? Salmonella is one of the major food-borne pathogens that cause systemic or enteric infection affecting approximately 2 million people worldwide each year. The first organism, Salmonella choleraesuis was isolated from a pig intestine by a scientist named Dr. Daniel   Salmon. Salmonella belongs to a member of the Enterobacteriaceae family and only two species of Salmonella namely S. enterica and S. bongori are pathogenic and cause illness to humans. What is Salmonellosis? Salmonellosis is a serious disease … Read more

Neisseria meningitidis vs Neisseria gonorrhoeae- 32 Differences

Differences between Neisseria meningitidis and Neisseria gonorrhoeae

Neisseria meningitidis and Neisseria gonorrhoeae, are obligate human pathogens that cause distinctly different disease syndromes. They are both Gram negative diplococci, non-sporing, oxidase positive and difficult to differentiate on morphological and cultural characteristics. However, they can be differentiated on the following grounds: S.N. Character Neisseria gonorrhoeae Neisseria meningitidis 1.       Commonly Called Gonococcus Meningococcus 2.       Causative agent of Sexually transmitted disease- Gonorrhoea Causes a range of diseases embraced by the term invasive meningococcal disease. Most commonly cerebrospinal meningitis. 3.       Cell Morphology … Read more

Campylobacteriosis- Campylobacter Infection and Food Poisoning

Campylobacteriosis- Campylobacter Infection and Food Poisoning

What is Campylobacteriosis? Campylobacter infection causes human gastroenteritis and vibriosis affecting people worldwide. It is a common bacterial disease that usually occurs in both developed and developing countries. The disease is endemic in North America, Europe, Australia, Africa, Asia, and the Middle East especially during the summer and early autumn. Campylobacteriosis is a food-borne disease that affects children, elders and weakened immune patients mainly in low-income countries however, adults are rarely infected which may be due to their acquired immunity … Read more

Pneumococcus vs Viridans streptococci- 12 Major Differences

Differences between Pneumococcus and Viridans streptococci

Streptococcus pneumoniae can be differentiated from Viridans streptococci by various features: S.N. Properties Pneumococcus Viridans streptococci 1 Morphology Lanceolate or flame-shaped Round/oval 2 Arrangement Gram-positive cocci in pairs Gram-positive cocci in long chains 3 Capsule Present Absent 4 On blood agar Draughtsman or carom coin colony Convex shaped colony 5 Liquid medium Uniform turbidity Granular turbidity 6 Bile solubility Soluble in bile Insoluble in bile 7 Inulin fermentation Fermenter Non-fermenter 8 Optochin Sensitive Resistant 9 Mice Pathogenicity Pathogenic Non-pathogenic 10 … Read more

O antigen and H antigen- Definition and 21 Key Differences

Differences between O Antigen and H Antigen

Difference between O Antigen and H Antigen The surface structures of bacteria have considerable antigenic heterogeneity. Often these antigens are used as part of a serologic classification system for the bacteria. The classification of the 2000 or so different Salmonellae is based principally on the types of the O (LPS side chain) and H (flagellar) antigens. The antigenic type of the bacteria may be a marker for virulence, related to the clonal nature of pathogens, although it may not actually … Read more

Anthrax bacilli vs Anthracoid bacilli- 25 Differences

Differences between Anthrax bacilli and Anthracoid bacilli

The saprophytic organisms which simulate the anthrax bacillus closely, both in their morphological and cultural characters within the group of Gram-positive aerobic sporing bacilli are termed as Anthracoid bacilli. They have a general resemblance to anthrax bacilli such as producing dry wrinkled colonies and in the smear, appearing as chains of spore-bearing gram-positive bacilli. However, they differ from anthrax bacilli in many ways as follows: S.N. Character Anthrax bacilli Anthracoid bacilli 1.       Known as Bacillus anthracis B. anthracis similis, … Read more

Bacillus cereus food poisoning with foodborne toxins


What is Bacillus cereus? Bacillus cereus is a pathogenic food-borne illness-causing organism that is widely distributed in nature such as on plants, soils, and GI tracts of insects and mammals. They are also present in food production plants and are capable of contaminating a large number of raw materials and food products due to their resistant endospores that can survive in harsh conditions. Bacillus cereus is a causative pathogenic organism that causes two types of food poisoning disease: the diarrheal … Read more