Differences between Staphylococcus and Streptococcus

Staphylococcus and Streptococcus Differences

Differences between Staphylococcus and Streptococcus 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 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.       … Read moreDifferences between Staphylococcus and Streptococcus

Habitat and Morphology of Acinetobacter baumannii

Habitat and Morphology of Acinetobacter baumannii

Habitat of Acinetobacter baumannii The first Acinetobacter found in soil was discovered in 1911 by M.W. Beijerinck. It is associated with aquatics environment. It has been recovered from soil, water, animals, and humans. Found in the respiratory and oropharynx secretions of infected individuals. Found in hospital environment and accounts for 10% nosocomial infections in ICU. It … Read moreHabitat and Morphology of Acinetobacter baumannii

Habitat and Morphology of Gardnerella vaginalis

Habitat and Morphology of Gardnerella vaginalis

Habitat of Gardnerella vaginalis Normal flora in 40% female (small amount) Found in urine Rarely in blood and wound Found in the anorectal flora of healthy adults of both sexes and as well as children. Isolated from normal vagina of reproductive age female & male urethra (partners of women with bacterial vaginosis). Optimum pH for growth … Read moreHabitat and Morphology of Gardnerella vaginalis

Flagella and Pili (Fimbriae)

Flagella and Pili (Fimbriae)

Flagella Flagella are protein filaments that extend like long tails from the cell membranes of certain gram-positive and gram-negative bacteria. These tails, which are several times the length of the bacterial cell, move the bacteria around. Source: Wikipedia The flagellum is affixed to the bacteria by a basal body. The basal body spans through the … Read moreFlagella and Pili (Fimbriae)

Habitat and Morphology of Chlamydia trachomatis

Habitat and Morphology of 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, … Read moreHabitat and Morphology of Chlamydia trachomatis

Aerobic and Facultatively Anaerobic Gram-Positive Cocci

Aerobic and Facultatively Anaerobic Gram-Positive Cocci

Enterococcus faecalis and Enterococcus faecium Clinical Features Urinary tract infections, peritonitis, bacteremia, endocarditis Virulence Factors Relatively avirulent Staphylococcus aureus Clinical Features Suppurative infections: impetigo, folliculitis, furuncles, carbuncles, wounds Disseminated infections: bacteremia, endocarditis, pneumonia, empyema, osteomyelitis, septic arthritis Toxin-mediated infections: toxic shock syndrome, scalded skin syndrome, food poisoning Virulence Factors Possess thick peptidoglycan layer, capsule, protein … Read moreAerobic and Facultatively Anaerobic Gram-Positive Cocci

Culture media used in Microbiology with their uses

Culture media used in Microbiology with their uses

A7 and A8 agars A7 and A8 agars are selective and differential media used for the cultivation, identification, and differentiation of Ureaplasma spp. and Mycoplasma hominis.   Alkaline peptone water Alkaline peptone water is an enrichment broth used for the isolation of small numbers of Vibrio and Aeromonas organisms from stool specimens.   American Trudeau … Read moreCulture media used in Microbiology with their uses

Gram-positive cell wall

Gram-positive cell wall

Prokaryotic cells almost always are bounded by a fairly rigid and chemically complex structure present between the cell membrane and capsule/slime layer called the cell wall. Peptidoglycan is the main component of the cell wall and is responsible for the shape and strength of the cell. It is a disaccharide and contains two sugar derivatives—N-acetylglucosamine … Read moreGram-positive cell wall

Antimicrobial Susceptibility Testing (AST)- Types and Limitations

Antimicrobial Susceptibility Testing (AST)

In the treatment and control of infectious diseases, especially when caused by pathogens that are often drug resistant, susceptibility (sensitivity) testing is used to select effective antimicrobial drugs. Susceptibility testing is not usually indicated when the susceptibility reactions of a pathogen can be predicted, for example: – Proteus species are generally resistant to nitrofurantoin and tetracyclines, … Read moreAntimicrobial Susceptibility Testing (AST)- Types and Limitations

Collection and transport of stool specimens

Collection and transport of stool specimens

Faecal specimens should be collected in the early stages of the diarrhoeal disease, when pathogens are present in the highest number, and preferably before antimicrobial treatment is started, if appropriate. The specimen should be collected in the morning to reach the laboratory before noon, so that it can be processed the same day. Formed stools … Read moreCollection and transport of stool specimens