Case scenario

A 35 year male presents with Three days history of Fever with chills, 2-3 episodes per day.

He also has Cough with minimal expectoration since Two days.

Since one day his sputum has become slightly brownish.

Now he has right lower chest pain. Increases with coughing and deep breathing.

Pneumococcal InfectionsDr. Jayaprakash Appajigol

Introduction

• Streptococcus pneumoniae also called as pneumococcus is the most common bacteria causing community acquired pneumonia.

• Also Known as Diplococci due to the growth pattern in liquid media

Microbiology• Pneumococci is a catalase negative , gram positive

coccus (round) capsulated bacteria growing in chainform.

• It produces an alpha hemolytic toxin known as Pneumolysin that breaks down heamoglobin.

• A polysaccharide capsule is present in all except the conjunctivitis causing strains, thus preventing phagocytosis and is an important virulence factor.

Microbiology

• The Quellung reaction, also called the Neufeld reaction, is a biochemical reaction in which antibodies bind to the bacterial capsule of Streptococcus pneumoniae causing swelling of capsule.

Gram Staining

Pneumococci growing on blood agar

- Illustrating α hemolysis -optochin sensitivity (zone around optochin disk). -Inset:Gram’s stain, illustrating gram-positive diplococci.

Pathogenesis• Pneumococcus has Pneumococcal surface protein a PspA and

pneumococca surface adhesin a PsaA .

• Pneumococcal cell wall constituents and antibody antigen reactions activate compements and release cytokines such as IL6, TNF alpha and IL –1 beta resulting in influx of PMN’s. The capsule prevents phagocytosis and promotes invasion.

• Pneumolysin causes the damage of respiratory tract membranes.

• Immunoglobulin Iga1 protease dampens mucosal immunity.

Miscellaneous

-Infancy and old age; -prior hospitalization;-alcoholism; malnutrition; -cigarette smoking;-prisons, homelessshelters

Infections Caused by Pneumococci

• Upper Respiratory Tract Infections : ASOM, Acute Sinusitis, Tracheobronchitis

• Lungs: Lobar Pneumonia• Pleura: Empyema • CNS: Acute pyogenic Meningitis, Brain Abcess• Heart: Endocarditis , Pericarditis

Pneumonia • Pneumococcal Pnemonia is diagnosed clinically on the basis

of fever(high grade), cough with purulent rusty sputum rarely heamoptysis and breathlessness.

• Some patients may present with features such as confusion fatigue and minimal cough.

• On Examination of the chest diminished chest movements of the effected side with impaired percussion note , bronchial breath sounds will be heard.

Crackles or coarse crepitations might be heard.

Chest X-ray showing Right lower lobe pneumonia typical of pneumococcal infection

Investigations

• sputum gram staining shows gram positive diplococci and sputum cultures confirm the clinical diagnosis.

• A rapid Pneumococcal urinary antigen assay can also be used .

Severity of pneumonia

Treatment • Beta Lactams are the mainstay of treatment.

• Oral amoxyciliin 20-40mg/kg/day for 10 days with or without clavulanate, newer macrolides newer fluoroquinolones like levofloxacin / moxifloxacin or first gen cephalosporins can be used .

• I.V Penicillin G 4milion units q4h or a 3rd generation cephalosporin like ceftriaxone 1g b.d. can be used in addition a macrolide or an aminoglycoside can be added

Acute Pyogenic Meningitis• Most common cause of pyogenic meningitis in adults . • It is characterised by

Rapid onset of high grade fever, headache, meningismus(neck stiffness and positive kernig’s sign), altered mental status .

Investigations

Lumbar Puncture

• It should be done only after ruling out disc oedema, stroke and coagulopathy.

• Findings include: pleocytosis 500 cells with predominant polymorphs elevated protein levels (0.1g/dl to 0.5g/dl) and a decrease in the glucose content .

Treatment is given for a minimimum of 10-14 days accordingly

Prevention of Pneumococcal Infections

Currently 2 types of vaccines are available :

• Pneumococcal polysaccharide PPS V23

• Pneumococcal conjugate vaccine PCV 13

Immunisation

Indications

Pneumococci is a Gm +ve flame shaped capsulated diplococci.

Pneumococcal infections can be life threatening like Pneumonia, meningitis and sepsis.

Penicillin, Cephalosporin are effective antibiotics.

Vaccines for prevention of the disease are available and effective.

Conclusions

Questions