Revision of Microbiology for MUSIII -2024 PDF

Final Revision of Microbiology for MUS III –SUMMER 2024  Medical Microbiology and 18-Jul-24 Immunology Department- MTI  Bacterial infections of the skin & Soft tissue Staphylococci ✓Gram-positive cocci arranged in irregular grap...

Final Revision of Microbiology for MUS III –SUMMER 2024  Medical Microbiology and 18-Jul-24 Immunology Department- MTI  Bacterial infections of the skin & Soft tissue Staphylococci ✓Gram-positive cocci arranged in irregular grape-like 18-Jul-24 clusters, non-motile, and non- spore forming. Medical Microbiology and Immunology Department- MTI ✓Produce endopigments e.g. white and golden yellow pigments. ✓All are catalase positive.  Virulence Factors Cell Toxins Enzymes components Protein A. Enterotoxin. Coagulase. 18-Jul-24 Clumping Toxic shock Beta factor. syndrome toxin lactamases. Medical Microbiology and Immunology Department- MTI Teichoic acid. (TSST). Fibrinolysin, Peptidoglycan. Exfoliatin. hyaluronidase, Capsule. Leukocidins. nucleases, proteases and lipases.  Streptococcus pyogenes ✓Gram-positive cocci arranged in chains or in pairs, non- motile, and non-spore forming. 18-Jul-24 Medical Microbiology and Immunology Department- MTI  Virulence Factors Cell Toxins and Enzymes components Hemolysins 18-Jul-24 ✓ M Protein. ✓ Erythrogenic toxin. ✓ Hyaluronidase. Medical Microbiology and Immunology Department- MTI ✓ Capsule ✓ Pyrogenic Exotoxin ✓ Streptokinase A. ✓ DNase ✓ Exotoxin B. (streptodornase ✓ Streptolysin O. ). ✓ Streptolysin S. ✓ IgG degrading enzyme.  I. Impetigo Causative Streptococcus pyogenes and organisms Staphylococcus aureus. Clinical -Affects children (2-5 years) 18-Jul-24 Manifestations -It spreads by direct contact. -Involves exposed areas of skin (face Medical Microbiology and Immunology Department- MTI and extremities) -adherent crusts with a characteristic golden “honey colored” appearance. Diagnosis -Clinically in most cases. Treatment Antibacterial therapy should be directed against both S. aureus and S. pyogenes.  Medical Microbiology and 18-Jul-24 Immunology Department- MTI  Quiz A 6-year-old boy with papular and pustular skin lesions on his face. A serous, “honey-colored” fluid exudes from the lesions. A Gram stain of the pus reveals many neutrophils and Gram-positive 18-Jul-24 cocci in clusters. Which of the following organisms is the MOST likely cause of this child’s Medical Microbiology and Immunology Department- MTI condition? A. Streptococcus pyogenes. B. Staphylococcus aureus. C. Staphylococcus epidermidis. D. Streptococcus pneumoniae The answer :B  II. Erysipelas Cellulitis Causative Streptococcus Streptococcus pyogenes, organisms pyogenes. Staphylococcus aureus. 18-Jul-24 Layer of skin Upper dermis and Deeper dermis and involved superficial subcutaneous fat Medical Microbiology and Immunology Department- MTI lymphatics. Diagnosis Clinically Treatment Empiric therapy against group A streptococci and S. aureus. Erysipelas Cellulitis Medical Microbiology and 18-Jul-24 Immunology Department- MTI A 28-years old woman presented with fever and an area of erythema and edema with well-demarcated edges on her face. Culture of pus obtained from the lesion revealed beta hemolytic, catalase-negative, Gram- positive cocci in chains that are and are inhibited by bacitracin. Which of the following organisms is the MOST likely cause of this patient’s condition? 18-Jul-24 A. Staphylococcus aureus. B. Streptococcus pyogenes. Medical Microbiology and Immunology Department- MTI C. Staphylococcus epidermidis. D. Streptococcus agalactiae. The answer :B  Gas Gangrene (Myonecrosis) Causative Contamination of deep lacerated wound with spores organism ↓ Impairment of normal blood supply of 18-Jul-24 Clostridium traumatized tissue perfringens. Medical Microbiology and Immunology Department- MTI consequent reduction in oxygen tension → anaerobic focus Spores germinates, vegetative bacteria multiply and ferment carbohydrates →produce gas. The distention of tissue, interference with blood with secretion of toxins → spread of infection  Clinical Manifestations and diagnosis Pain, edema, cellulitis, and gangrene (necrosis) in the wound area. Clinical Crepitus is palpated →indicates gas in the Manifestations tissue 18-Jul-24 Medical Microbiology and Immunology Department- MTI Nagler’s reaction Diagnosis Treatment Penicillin G is the antibiotic of choice. Debridement of devitalized tissue  Toxin mediated skin diseases 1.Scalded Skin Syndrome S. aureus ✓producing exfoliatin toxin. It 18-Jul-24 Causative organism is “epidermolytic” acts as a protease separating the Medical Microbiology and Immunology Department- MTI epidermis from the dermis. Clinical ✓Occurs mostly in young manifestations children  2. Toxic shock syndrome Staphylococcus toxic Streptococcal toxic shock shock syndrome syndrome 18-Jul-24 - Caused by strains of S. - Pyrogenic exotoxin A is aureus producing TSST. responsible for Streptococcal Medical Microbiology and Immunology Department- MTI toxic shock syndrome. Clinical manifestations:  Diagnosis and Treatment -Clinically -ELISA→detect TSST in serum 18-Jul-24 -Isolation of a TSST producing strain of Diagnosis S. aureus -Blood cultures Medical Microbiology and Immunology Department- MTI Supportive measures. Antimicrobials. Debridement of infected tissues Treatment  Case A few days after birth, a newborn developed an umbilical infection from which Gram-positive cocci in clusters were isolated. The next day he appeared “sunburned” and the superficial layers of his skin peeled away. Which of the following toxins is most likely responsible 18-Jul-24 for the cutaneous findings in this case? A. Pyrogenic exotoxin Medical Microbiology and Immunology Department- MTI B. Exotoxin A. C. Erythrogenic toxin. D. Exfoliatin toxin. The Answer :D  Leprosy Causative Mycobacterium leprae organism -It doesn’t grow on artificial media or. in cell culture -It can be grown in experimental animals e.g. armadillos. 18-Jul-24 Medical Microbiology and Immunology Department- MTI Mode of Prolonged contact with patients with transmission lepromatous leprosy Pathogenesis -The organism replicates intracellularly -The nerve damage in leprosy is the result of two processes: -Direct contact with the bacterium -Cell mediated immunity  Forms of leprosy Tuberculoid Lepromatous Feature leprosy leprosy Lesions Few Multiple 18-Jul-24 Medical Microbiology and Immunology Department- MTI NO of bacilli Few Many Transmission Low High CMI response Present Reduced or absent Laboratory - Modified Ziehl- Neelsen Diagnosis -PCR Treatment Combination therapy  Skin manifestation of Medically important diseases 1) Cutaneous Anthrax (Malignant pustule) 18-Jul-24 Causative Bacillus anthracis Medical Microbiology and Immunology Department- MTI organism Virulence a-Anthrax toxin factors b- Capsule (poly peptide) Mode of Anthrax disease is zoonotic disease transmission -Human is accidentally infected through: Inoculation cutaneously from infected animals  Skin manifestation of Medically important diseases Cutaneous Anthrax (Malignant pustule) 18-Jul-24 Causative Bacillus anthracis Medical Microbiology and Immunology Department- MTI organism Virulence a-Anthrax toxin factors b- Capsule (poly peptide) Mode of Anthrax disease is zoonotic disease transmission -Human is accidentally infected through: Inoculation cutaneously from infected animals  Virulence factors 18-Jul-24 ❖Anthrax toxin (two exotoxins, Edema factor and Lethal factor) Medical microbiology and immunology department- MTI ❖ Capsule ✓ Composed of poly peptide D- glutamate. ✓ Antiphagocytic.  Clinical manifestations 18-Jul-24 Medical Microbiology and Immunology Department- MTI Painless ulcer with a black eschar (crust) and Local edema.  Causative organisms of wound infections 18-Jul-24 Trauma Surgical site Burns Clostridium. Staphylococcus Pseudomonas Medical Microbiology and Immunology Department- MTI aureus. Enterobacteria Staphylococcus aeruginosa. ceae epidermidis. S. aureus. Pseudomonas Enterococci. Enterobacteria aeruginosa. Enterobacteriacea. cea Anaerobes.  Pseudomonas aeruginosa -Gram-negative bacilli -Able to grow in water →persistence in the hospital environment. Characteristics -Produces two pigments : 18-Jul-24 a) Pyocyanin Medical Microbiology and b) Pyoverdin Immunology Department- MTI 1.Exotoxin A 2. Enzymes e.g. elastase & Virulence Factors proteases. 3. Endotoxin. An opportunistic pathogen that causes infections in patients with Pathogenesis lowered host defenses as burn patients.  Virulence Factors Endotoxin 18-Jul-24 Causes the symptoms of sepsis and septic shock. Enzymes e.g. elastase and proteases. Toxic to tissues and facilitate invasion of Medical microbiology and immunology department- MTI the organism into the bloodstream. Exotoxin A Inhibits protein synthesis causing tissue necrosis.  Case A 30-year-old man with a 2-cm lesion on his arm. It began as a painless papule that enlarged and, within a few days, ulcerated and formed a black crust (eschar). He works in an abattoir where his job is removing the hide from the cattle. A Gram stain of fluid from the 18-Jul-24 lesion reveals large Gram-positive bacilli. Which of the following bacteria is the most likely cause of his condition? Medical Microbiology and Immunology Department- MTI A. Bacillus anthracis. B. Clostridium botulinum. C. Clostridium perfringens. D. Clostridium tetani. The Answer :A  Case A 30-years old patient with third-degree burns over most of his body developed fever, and his dressings revealed pus that had a blue-green color. Gram stain of the pus revealed oxidase positive, Gram-negative bacilli. Which of the following organisms 18-Jul-24 is the most likely cause of this infection? A. Klebsiella pneumoniae. Medical Microbiology and Immunology Department- MTI B. Pseudomonas aeruginosa. C. Escherichia coli. D. Proteus mirabilis. The Answer :B  Case A 20-year-old man with a single, slowly expanding, nonpainful lesion on his arm for the past 2 months. He has lost sensation at the site of the lesion. An acid-fast stain of a scraping of the lesion is positive. Which of the following diseases is he most likely diagnosis of this 18-Jul-24 patient’s condition? A. Cutaneous tuberculosis. Medical Microbiology and Immunology Department- MTI B. Lepromatous leprosy. C. Tuberculoid leprosy. D. Ring worm. The Answer :C  Forms of viral skin lesions 1. Vesicular 2. Maculopapular lesions lesions 18-Jul-24 Lesions are immunologically Medical microbiology and Immunology department- MTI Lesions are sites mediated of virus (the virus can be replication shed from other sites) Infectious Non- infectious  Medical microbiology and 18-Jul-24 Immunology department- MTI  Herpes Simplex Viruses 1,2 Members of Herpes virus family with icosahedral capsid and Linear double- 18-Jul-24 stranded DNA genome Medical microbiology and Immunology department- MTI Establish (HSV-1) Enveloped latent and viruses infections (HSV-2) replicate in nucleus & form intranuclear inclusions. Replication  Herpes labialis Herpetic whitlow Gingivostomatitis Medical microbiology and 18-Jul-24 Immunology department- MTI  Varicella-Zoster Virus (VZV) Causes:- Varicella (chickenpox) is the primary disease 18-Jul-24 - Zoster (shingles) is the recurrent form Mode of Transmitted by : Medical microbiology and Immunology department- MTI Transmission respiratory droplets direct contact with the lesions. Pathogenesis -VZV infects the mucosa of the upper respiratory tract→ spreads via the blood to the skin→ causing the typical vesicular rash. -The virus remains latent in dorsal root ganglia  Medical microbiology and 18-Jul-24 Immunology department- MTI  Clinical manifestations Varicella (chickenpox) Zoster (shingles) 18-Jul-24 -highly contagious disease -Occur in adults or Medical microbiology and Immunology department- MTI of childhood immunocompromised patients Complications: Complications: Pneumonia Post herpetic neuralgia In immunocompromised Encephalitis patients: life-threatening disseminated infections Reye’s syndrome e.g. pneumonia.  Diagnosis and treatment Clinically. Diagnosis Treatment Acyclovir 18-Jul-24 Prevention Medical microbiology and Immunology department- MTI 1. Active 2. Passive 3. Immunization Immunization Chemoprophylaxis (Two live attenuated vaccines) Varicella Acyclovir Zoster a. The varicella immunoglobul vaccine b. The zoster in (VZIG) vaccine  A 3-year-old girl presented to her pediatrician’s office with fever, swollen lymph nodes, and a vesicular rash on her chest and upper arms. On examination, the vesicles were at various stages of development: some were newly forming, while some were crusted over. 18-Jul-24 Which of the following infectious agents is the most Medical microbiology and Immunology department- MTI likely cause of this girl’s rash? A. Smallpox. B. Parvovirus B19. C. Measles virus. D. Varicella-zoster virus. The Answer : D  Medical microbiology and 18-Jul-24 Immunology Department- MTI  Viral infections causing Maculopapular skin lesions Measles virus -Single-stranded -ve sense RNA. characteristics -Enveloped virus. 18-Jul-24 -A single serotype. Mode of Mainly by Medical microbiology and Immunology Department- MTI transmission Respiratory droplets Infecting the cells lining the upper respiratory tract ↓ virus enters the blood and infects Pathogenesis reticuloendothelial cells ↓ Spreads via the blood to the skin (vascular endothelial cells in the skin).  Clinical manifestations Prodromal phase: fever, conjunctivitis (photophobia), running nose & coughing. 18-Jul-24 Bright red Koplik’s lesions located spots on the buccal Medical microbiology and Immunology Department- MTI mucosa. Appears on the Maculopapular face and proceeds rash down to the lower extremities.  Medical microbiology and 18-Jul-24 Immunology Department- MTI  Complications Encephalitis: 1:1000 cases of measles. -- -Subacute sclerosing panencephalitis (SSPE): A rare fatal disease of the CNS. Occurs several years after 18-Jul-24 measles. - Pneumonia: Primary by measles & secondary bacterial Medical microbiology and Immunology Department- MTI pneumonia. -Otitis media.  Rubella virus A member of the Togavirus family. Enveloped virus, single-stranded +ve sense RNA. Has a single serotype. 18-Jul-24 Mode of respiratory droplets. Transmission Medical microbiology and Immunology Department- MTI Initial replication of the virus occurs in the nasopharynx and local lymph nodes. ↓ it spreads via the blood to the internal organs and Pathogenesi skin s ↓ Natural infection leads to lifelong immunity  Clinical manifestations and diagnosis -Maculopapular rash→ starts on the face and progresses downwards Clinical -Posterior auricular lymphadenopathy is 18-Jul-24 manifestations characteristic. Medical microbiology and Immunology Department- MTI Laboratory -Isolation in cell culture. Diagnosis -Serology: a fourfold or greater rise in antibody titer. -PCR assay: to detect viral RNA Prevention Active immunization:→A live, attenuated vaccine MMR vaccine  Rubella Medical microbiology and 18-Jul-24 Immunology Department- MTI  Case A 20 year old female developed fever and malaise then a maculopapular rash appeared on her face and spreads to her arms 2 days ago. On examination, enlarged posterior auricular lymph nodes were seen. 18-Jul-24 Which of the following viruses is the most likely etiologic Medical microbiology and Immunology Department- MTI agent of this patient’s condition? A. Measles virus. B. Parvovirus B19. C. Rubella virus. D. Herpesvirus 6. The answer :C  Quiz Kolpik’s spots is characteristic to which of the following viral diseases? A. Measles. B. Rubella. 18-Jul-24 C. Varicella. D. Shingles. Medical microbiology and Immunology Department- MTI The answer :A Skin & Subcutaneous Fungal Diseases Fungus Forms in Mode of Clinical Tissue Seen transmission manifestations by Microscopy 18-Jul-24 Trichophyton, Human to human Ring of inflammatory, Epidermophyt pruritic vesicles with a on healing center Medical Microbiology and Immunology Department-MTI Microsporum Animal to human & human to human Malassezia Human to human Scaly plaques on trunk, hypopigmented or hyperpigmented & nonpruritic Sporothrix Penetrating lesion Pustule or ulcer on in garden hands often with implants fungal nodules on arms spores, e.g., rose  Cutaneous mycoses Tinea versicolor (Pityriasis versicolor) Causative organism 18-Jul-24 Malassezia species Medical Microbiology and Immunology Department-MTI Clinical manifestations Hypopigmented or hyperpigmented Affect he trunk or proximal parts of the limbs. Asymptomatic may be scaling or itching Laboratory Diagnosis Detecting BOTH yeast cells & hyphae in KOH preparations of skin scrapings 18-Jul-24 Malassezia furfur, showing yeast & hyphal forms (spaghetti & meatballs) Medical Microbiology and Immunology Department-MTI Treatment Topical miconazole  Dermatophytoses (Tinea, Ringworm) Causative organism Epidermophyton 18-Jul-24 Dermatophytes (mold fungi) Medical Microbiology and Immunology Department-MTI Microsporum Mode of transmission Direct contact from infected person or animal Trichophyton  Clinical manifestations 18-Jul-24 Medical Microbiology and Immunology Department-MTI Tinea corporis Tinea pedis Tinea capitis ( body) (The foot) ( head) Tinea cruris (The groin) Tinea unguim (The nails)  Laboratory Diagnosis Scrapings of skin or nail placed in 10% KOH on a glass slide: septate hypha under microscopy. Cultures on Sabouraud’s agar at room temperature: typical hyphae & 18-Jul-24 conidia. Lesions caused by Microsporum Medical Microbiology and Immunology Department-MTI detected by observing fluorescence when the lesions are exposed to ultraviolet light from a Wood’s lamp. Treatment Local antifungal creams  Subcutaneous mycoses Sporotrichosis Causative organism Sporothrix is a dimorphic fungus 18-Jul-24 Clinical manifestations Painless local pustule or ulcer with Medical Microbiology and Immunology Department-MTI nodules. Laboratory diagnosis 18-Jul-24 ✓Round shaped budding yeasts ✓In culture on Sabouraud’s Medical Microbiology and Immunology Department-MTI are seen in tissue specimens. agar at room temperature: hyphae and conidia are seen. Prevention Protecting skin when touching plants, and wood Treatment Itraconazole  Case A woman who pricked her finger while pruning some rose bushes develops alocal pustule that progresses to an ulcer. Which of the following is the most likely etiologic 18-Jul-24 agent of this condition? Medical Microbiology and Immunology Department-MTI A. Cryptococcus neoformans. B. Candida albicans. C. Sporothrix. D. Aspergillus fumigatus. Answer C  Case A 30-year old woman complains of an “itching rash” on her abdomen. On examination, the lesions are red, circular, with a vesiculated border and a healing central area. You suspect tinea corporis. Which of the 18-Jul-24 following is the MOST appropriate laboratory procedure to make the diagnosis? Medical Microbiology and Immunology Department-MTI A. Potassium hydroxide mount of skin scrapings. B. Giemsa stain for multinucleated giant cells. C. Fluorescent antibody stain of the vesicle fluid. D. Fourfold rise in antibody titer against the organism. Answer A  CASES Medical Microbiology and 18-Jul-24 Immunology Department- MTI  Case study The mother of a 2-year-old girl brings the child for the evaluation of a lesion on her index finger. 18-Jul-24 It has been present for 3 or 4 days and seems to cause some pain. The week prior, the child had fever and painful vesicular lesions on the tongue, Medical Microbiology and Immunology Department- MTI lips, floor and roof of her mouth , all of which have resolved. She has never had warts, and the mother says that the child is otherwise healthy. On examination, her right index finger has a cluster of small vesicles with a faint area of surrounding erythema. The remainder of the child’s examination is normal. 1. What is your provisional diagnosis and the most likely cause of this skin lesion? 2. How was it transmitted to this child’s index 18-Jul-24 finger? 3. How can you confirm your diagnosis? Medical Microbiology and Immunology Department- MTI 4. What is the proper treatment and preventive measures for this condition?  What is your provisional diagnosis and the most likely cause of this skin lesion? Herpetic whitlow, Herpes simplex type 1. 18-Jul-24 How was it transmitted to this child’s index finger? Medical Microbiology and Immunology Department- MTI The child most likely acquired the infection via direct contact of the skin by suckling her index finger.  How can you confirm your diagnosis? Usually clinically Laboratory diagnosis: 18-Jul-24 -Isolation of the virus: growth in cell culture. -A rapid presumptive diagnosis can be made from Medical Microbiology and Immunology Department- MTI skin lesions by using the Tzanck smear. -PCR assay to detect viral DNA. -Serologic tests: primary infections, no use in the diagnosis of recurrent infections.  What is the proper treatment and preventive measures for this condition? Treatment: 18-Jul-24 Acyclovir (Inhibition of viral nucleic acid Synthesis): useful for the treatment of primary and recurrent herpes infection shortens the duration of the lesions and reduces the extent of shedding of the virus Medical Microbiology and Immunology Department- MTI but does not cure the latent state. Prevention: Avoid contact with the vesicular lesions or ulcers. Acyclovir is used to prevent viral reactivation in immunocompromised patients.  Case study A 9-year- old boy presented to the emergency department with fever, a diffuse rash (onset 5 days 18-Jul-24 before), and a swollen right hand. On examination he was irritable but alert. His temperature was 39°C and heart rate was increased at 180 beats/min. He had Medical Microbiology and Immunology Department- MTI diffuse vesiculopustular lesions over his entire body with some areas showing older, crusted lesions. There were no mouth lesions, the lungs were clear, and the liver and spleen were not enlarged. 1. What is your diagnosis about this boy’s underlying viral illness and Mention the most likely etiologic agent? 18-Jul-24 2. What are the MOST likely modes of transmission of this viral disease? 3. What complications can occur as a result of this Medical Microbiology and Immunology Department- MTI viral infection? 4. What illness may occur years later as a result of viral reactivation? How do the clinical manifestations of this reactivation infection differ from those of primary infection? 5. How can we prevent this condition?  What is your diagnosis about this boy’s condition and Mention the most likely etiologic agent? The patient’s underlying viral illness was varicella (chicken pox). This illness is due to primary infection with varicella-zoster virus (VZV). 18-Jul-24 Varicella lesions develop in “crops” such that lesions can be seen in various stages of evolution, including vesicular, pustular, and crusted. Medical Microbiology and Immunology Department- MTI What are the MOST likely modes of transmission of this viral disease? Transmitted by respiratory droplets and direct contact with the lesions. What complications can occur as a result of this viral infection? Pneumonia and encephalitis: more in adults. Reye’s syndrome: encephalopathy and liver degeneration, is associated with infection, especially in children given aspirin. What illness may occur years later as a result of viral reactivation? How do the clinical manifestations of this reactivation infection differ from those of primary infection? Herpes zoster (shingles) is a reactivation of a latent VZV infection. The dorsal root 18-Jul-24 ganglia are latently infected following primary infections. Zoster Occur in adults or immunocompromised patients and is Characterized by painful vesicles along the course of a sensory nerve of the head or trunk (unilateral). Medical Microbiology and Immunology Department- MTI  How can we prevent this condition? Medical Microbiology and 18-Jul-24 Immunology Department- MTI  Case study A 14-month-old girl is brought to emergency room with a 3-day history of high fever, cough and runny nose. Upon physical examination, the physician notes small white spots on the inside of the child’s mouth and catarrhal inflammation within the nose. The child also shows signs of conjunctivitis in the both eyes. The mother reports that the child is lethargic and refuses to eat. The child attends a private day care and is not current with vaccinations. Medical Microbiology and Immunology 18-Jul-24 Department- MTI 1. What is your provisional diagnosis of this girl’s presentation? 2. The physician noticed small white spots on 18-Jul-24 the inside of the child’s mouth, what is these lesions and mention their Medical Microbiology and Immunology Department- MTI significance? 3. What is the sign that most likely to manifest in this patient within the next few days? 4. What complications can occur as a result of this infection? 5. How can we diagnose this condition? 6. What are the preventive measures for this condition?  What is your provisional diagnosis of this girl’s presentation? Measles. The physician noticed small white spots on the inside of the child’s mouth, What is these lesions and mention their significance? Koplik’s spots: are bright red lesions with a white, central dot that are located on the buccal 18-Jul-24 mucosa shortly before rash appears and are diagnostic. What is the sign that most likely to manifest in this patient within the next few days? Maculopapular rash appears on the face and proceeds down the body to the lower extremities, including the palms and soles (3-7 days). Medical Microbiology and Immunology Department- MTI  What complications can occur as a result of this infection? ✓ Encephalitis: 1:1000 cases of measles. ✓ Primary measles pneumonia and secondary bacterial pneumonia. ✓ Otitis media. ✓ Subacute sclerosing panencephalitis (SSPE): a rare, fatal disease of the CNS that 18-Jul-24 occurs several years after measles. How can we diagnose this condition? Medical Microbiology and Immunology Department- MTI Most diagnosis of measles is made Clinically. Laboratory diagnosis: Virus isolation in cell culture and identification by with characteristic CPE (Formation of multinucleated giant cells containing BOTH intranuclear and intracytoplasmic inclusion bodies. Serologic tests: greater than fourfold rise in antibody titer. PCR assay: to detect viral RNA.  What are the preventive measures for this condition? Active immunization: The live attenuated vaccine. 18-Jul-24 It is given subcutaneously to children usually in combination with rubella and mumps vaccines (MMR vaccine). Medical Microbiology and Immunology Department- MTI Two doses at 15 months a booster dose at 4 to 6 years. The vaccine is effective and provides long-term immunity. Passive immunization: Immune globulin Recommended for unimmunized or immunocompromised individuals early in the incubation period.  Case study A few days after birth, a newborn developed an umbilical infection from which Gram-positive cocci in clusters were isolated. The next day he appeared “sunburned” and the superficial layers of his skin 18-Jul-24 peeled away. Medical Microbiology and Immunology Department- MTI What is your provisional diagnosis of this newborn’s condition ? Scalded skin syndrome 18-Jul-24 What is the most likely causative organism? Staphylococcus aureus Medical Microbiology and Immunology Department- MTI What is the toxin involved in the cutaneous findings in this case? Exfoliatin toxin  Case study A young woman has developed fever and hypotension three days into her menstrual cycle. Pelvic examination shows she is having her menstrual period with a tampon in place. Laboratory findings revealed abnormal kidney function tests. Blood cultures 18-Jul-24 grew catalase positive Gram-positive cocci in clusters. Medical Microbiology and Immunology Department- MTI What is your provisional diagnosis of this newborn’s condition ? Toxic shock syndrome. 18-Jul-24 What is the most likely causative organism? Staphylococcus aureus. Medical Microbiology and Immunology Department- MTI Which toxins is most likely responsible for the systemic manifestations in this patient? Toxic shock syndrome toxin.  Case study A 6-month old female infant developed erythematous lesions over perineum related to the area of skin in contact with the diaper. On examination, the lesions are red, moist with multiple vesicles. Microbiological culture of a specimen from those lesions 18-Jul-24 revealed Gram positive oval budding yeast cells. Medical Microbiology and Immunology Department- MTI What is your provisional diagnosis of this newborn’s condition ? Napkin dermatitis (Diaper rash). What is the most likely causative organism? 18-Jul-24 Candida albicans. Medical Microbiology and Immunology Department- MTI What is the treatment of choice for this infant? Topical antifungal drugs (e.g. clotrimazole or nystatin).  Case study A 15-year-old athlete presented to the dermatology clinic with cosmetically annoying skin rash on his back and upper limbs. On examination many hypopigmented lesions with scales were observed on the back and both upper limbs. Skin scrapings from the lesions were collected and 18-Jul-24 sent to the microbiology laboratory for examination. Microbiological examination of the scrapings with adding 10% KOH showed yeast cells and hyphae. Medical Microbiology and Immunology Department- MTI Yeast & hyphal forms (spaghetti & meatballs) What is your provisional diagnosis of this patient’s condition ? Tinea versicolor (pityriasis versicolor) What is the most likely causative organism? 18-Jul-24 Malassezia species (dimorphic fungi, the Most important is Malassezia furfur). Medical Microbiology and Immunology Department- MTI What is the treatment of choice for this patient? Topical miconazole is the treatment of choice. N.B. Recurrence (lesions have tendency to recur): Oral antifungal drugs (fluconazole or itraconazole).  Case study A woman who pricked her finger while pruning some rose bushes develops a local pustule that progresses to an ulcer. Microbiological 18-Jul-24 examination of a specimen from the ulcer revealed round shaped budding yeasts while culture on Sabouraud’s agar with incubation at Medical Microbiology and Immunology Department- MTI room temperature showed hyphae and conidia. What is your provisional diagnosis of this patient’s condition ? Sporotrichosis. 18-Jul-24 What is the most likely etiologic agent of this condition? Sporothrix. Medical Microbiology and Immunology Department- MTI What is the preventing measures that should be followed to prevent such condition? Protecting skin when touching plants, and wood.  Case 3 Answer: Medical microbiology and 18-Jul-24 immunology department- MTI