Question

Illness

“Jose, maybe you should go to CVS and see if they have something to help with your fever.” Jose was sitting in ‪the family room‬ crying louder by the minute. He has been this way for a few days. “I am starting to worry because he seems hotter than a couple of days ago, and is now complaining about not being able to swallow because of the pain,” the mother exclaimed. Moreover, his teacher said that lots of other kids in his kindergarten class have been staying home sick. She said that they are usually ‘out’ for a week.

Admittance

Over the next couple of days Jose’s condition exponentially worsened. He was rushed to the Eisenhower ER. A Resident made the following notes from the initial physical exam and lab tests:

Jose Lopez – Initial Report

DOB: 11-16-2006

Gender: Male - Weight: 45.2 lbs. - Height: 42 inches

PHI: 6 yo Hispanic male presents to ER with complaints of throat and ears hurting. Patient very agitated, fussy, and complaining that he cannot swallow with persistent cough. Parents report onset as 6 days ago with focus on throat only, with persistent and progressive pain every day. Mother reports increased sickness of his kindergarten class. Pain is described as burning and scratching by child with nothing alleviating any pain beyond the mint tea parents made.

Allergies: NKDA

Med Hx: Untold herbals, no Rx/OTC; Mother noted to contact local herbalist for list

FH/SH: Nothing disclosed by parents (some inherent distrust of Western medicine and slight language barrier); patient lives with parents and attends kindergarten

Vitals: T 39.9 degrees C, BP 110/71 mmHg, RR 40bpm, Pulse 110bpm

Physical exam:

(+) Drowsiness, agitation, opthorrhea, rhinorrhea, cough

(-) Epiglottitis, flushing, impetigo, circumoral pallor, rash, erysipelas

*Pharyngeal erythema with petechiae and dark white tonsillar exudates, tender, hypertrophied cervical lymph nodes

Initial Laboratory Results:

WBCs: 11,800/uL, Differential: 78% PMNs, 18% bands, 4% monos

Chest X-ray: clear

Urinalysis: hematuria, proteinuria

Throat and blood cultures pending

Plan: Consult Supervising Physician for optimal treatment

Progress

Before rounding with the care team this morning, you (the nurse) have a chance to meet with Jose and his parents. You decided to look up the progress notes made on him and find the following:

Day 0: Started on empiric therapy of Penicillin VK per Dr. Wong’s recommendations. Fever still persists but less agitation and runniness are noted, and improved diet and fluid intake is noted by nurse Susan. Around ‪2300, the nurse Susan alerted Dr.‬ Wong to a rash on Jose’s trunk and empiric therapy is discontinued.

Day 1: The throat culture on sheep blood agar revealed Streptococcus pyogenes (Streptococci) and Jose was given a diagnosis of streptococcal pharyngitis (strep throat). Blood culture confirms S. pyogenes. Gentamicin is initiated by the nurse with renal dosing per doctor. ECHO (diagnostic ultrasound) is scheduled for next afternoon.

Question

What are some of the microbiological properties and virulence factors produced by this pathogen? Explain the typical mode of transmission and the epidemiological properties.

Answer 1

Answer) Virulence factors produced by Streptococcus pyogenes-

• It utilises lipoteichoic acid along with M protein for attaching itself to the host cells.
• It inhibits phagocytosis with the help of hyaluronic acid capsule.
• It causes scarlet fever due to pyrogenic (erythrogenic) toxin.
• Other virulence factors are DNase B (streptodornase), streptokinase and streptolysin.

Microbiological properties produced by Streptococcus pyogenes-

• It is a Gram-positive.
• It is a nonmotile.
• It does not forms spores.
• Cocci usually occur in chains or they forms pairs with each other.
• They are facultative anaerobes.
• They are catalase negative.

Typical mode of transmission is through air by inhaling droplets from affected individuals; transmitted through food; and by coming in contact with the person’s skin or objects that are contaminated with Streptococci.

Epidemiological properties of Streptococcus pyogenes-

1-5% of healthy individuals are affected by this bacteria and suffer from sore throats, or vaginal and rectal infections. In children this rate is higher upto 2-17%.