Bacteriology

Klebsiella pneumoniae- Lab Diagnosis, Treatment, Prevention

Klebsiella pneumoniae- Lab Diagnosis, Treatment, Prevention

Laboratory Diagnosis of Klebsiella pneumoniae In the setting of pneumonia, infection with  K. pneumoniae is confirmed by either sputum culture analysis, blood culture analysis or midstream urine depending upon the illness. The presence of gram-negative rods in Gram-stained smears suggests Klebsiella; they maybe capsulated and non-sporing. Material is inoculated into blood agar and Mac Conkey agar … Read moreKlebsiella pneumoniae- Lab Diagnosis, Treatment, Prevention

Staphylococcus aureus- Lab Diagnosis, Treatment, Prevention

Staphylococcus aureus- Lab Diagnosis, Treatment, Prevention

Staphylococcus aureus are catalase-positive, gram-positive cocci which frequently colonize the skin and mucosa of humans and animals. However, it is a highly successful opportunistic pathogen and thus involved in various diseases including toxin-mediated diseases (food poisoning, toxic shock syndrome, scalded skin syndrome), pyogenic diseases (impetigo, folliculitis, furuncles, carbuncles, wound infections), and other systemic diseases. The … Read moreStaphylococcus aureus- Lab Diagnosis, Treatment, Prevention

E. coli- Lab Diagnosis, Treatment, Prevention and Control

E. coli- Lab Diagnosis, Treatment, Prevention and Control

Laboratory Diagnosis Urinary Tract Infection Most urine specimens are obtained from adult patients via the clean-catch midstream technique. Bacteriuria can be detected microscopically using Gram staining of uncentrifuged urine specimens, Gram staining of centrifuged specimens, or direct observation of bacteria in urine specimens. On staining, E coli appear as non-spore-forming, Gram-negative rod-shaped bacterium Routine urine … Read moreE. coli- Lab Diagnosis, Treatment, Prevention and Control

Clostridium perfringens- Pathogenesis, Clinical Features

Clostridium perfringens- Pathogenesis, Clinical Features

Clostridium perfringens- Pathogenesis, Clinical Features Clostridium perfringens (previously named Clostridium welchii) is a Gram-positive, rod-shaped, anaerobic, spore-forming pathogenic bacterium, which is found commonly in decaying vegetation and soils.  Along with many environmental sources, it is also found in the intestines of humans and animals.  Clostridium perfringens is the causative agent of a number of human diseases, … Read moreClostridium perfringens- Pathogenesis, Clinical Features

Acinetobacter baumannii- Lab Diagnosis, Treatment and Prevention

Acinetobacter baumannii- Lab Diagnosis, Treatment and Prevention

Laboratory Diagnosis The diagnosis of Acinetobacter infection is made by the growth of Acinetobacter from a patient specimen (eg, sputum, blood, cerebrospinal fluid) in the setting of other clinical findings that suggest an infection at that site. Since Acinetobacter colonization is common and treatment difficult and potentially associated with substantial toxicity, the distinction between colonization and infection, with treatment … Read moreAcinetobacter baumannii- Lab Diagnosis, Treatment and Prevention

Enteroinvasive E. coli (EIEC)

Enteroinvasive E. coli (EIEC)

Enteroinvasive E. coli (EIEC) Enteroinvasive E. coli (EIEC) strains are rare in both developed and developing countries. EIEC infections are characterized by a period of watery diarrhea that precedes the onset of scanty dysenteric stools containing blood and mucus. Pathogenic strains are primarily associated with a few restricted O serotypes: O124, O143, and O164. EIEC … Read moreEnteroinvasive E. coli (EIEC)

Morphology of Bacteria

Morphology of Bacteria

Morphology of Bacteria Morphologically bacteria can resemble: Cocci (Singular: coccus) Bacilli (rods) (Singular: rod, bacillus) Vibrios (Singular: vibrio) Spirilla (Singular: spirillum) Spirochaetes (Singular: spirochaete) Cocci These are round or oval bacteria measuring about 0.5–1.0 um in diameter.  When multiplying, cocci may form pairs, chains, or irregular groups: cocci in pairs are called diplococci, e.g. meningococci … Read moreMorphology of Bacteria

Differences between Pneumococcus and Viridans streptococci

Differences between Pneumococcus and Viridans streptococci

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 … Read moreDifferences between Pneumococcus and Viridans streptococci

Why TCBS agar is not autoclaved?

Why TCBS agar is not autoclaved

Answer: Thiosulfate-citrate-bile salts-sucrose (TCBS) Agar is used for the selective isolation of Vibrio cholerae and other enteropathogenic vibrios. TCBS agar is composed of yeast extract, peptone, sodium thiosulfate, sodium citrate, ox bile (oxgall), sucrose, sodium chloride, iron (III) citrate, bromothymol blue, thymol blue, agar, and distilled or deionized water. TCBS is not autoclaved because: This … Read moreWhy TCBS agar is not autoclaved?

Why MHA is used for antibiotic susceptibility testing?

Why MHA is used for antibiotic susceptibility testing

Answer: It is a non-selective, non-differential medium. This means that almost all organisms plated on here will grow. It contains starch. Starch is known to absorb toxins released from bacteria so that they cannot interfere with the antibiotics. It also mediates the rate of diffusion of the antibiotics through the agar. It is a loose … Read moreWhy MHA is used for antibiotic susceptibility testing?