Streptococcus pneumoniaeStreptococcus pneumoniaepneumococuspneumococus
PneumoniaPneumonia
MeningitisMeningitis
bacteraemiabacteraemia
Description Description
Gram-positive diplococci (in pairs)Gram-positive diplococci (in pairs)Encapsulated ovoid or lanceolate coccusEncapsulated ovoid or lanceolate coccusNon-motileNon-motileFastidious (enriched media)Fastidious (enriched media)– Blood or chocolate agarBlood or chocolate agar– 5-10 % CO25-10 % CO2
Alpha haemolysis + draughtsman appearance Alpha haemolysis + draughtsman appearance Some strains are mucoidSome strains are mucoidSoluble in bileSoluble in bileOptochin sensitive Optochin sensitive
Pathogenesis Pathogenesis Virulence factors Virulence factors – Capsular polysaccharide Capsular polysaccharide
The major factorThe major factor84 serotypes84 serotypesBoth antigenic and type specificBoth antigenic and type specificAntiphagocyticAntiphagocyticSerotype 3 , 7 are most virulent Serotype 3 , 7 are most virulent 90% of cases of bacteraemic pneumococcal 90% of cases of bacteraemic pneumococcal pneumonia and meningitis are caused by 23 pneumonia and meningitis are caused by 23 serotypes serotypes Quellung reaction , india ink Quellung reaction , india ink
– PneumolysinPneumolysinMembrane damaging toxinMembrane damaging toxin
Carrier rate Carrier rate – Oropharyngeal flora of 5 – 70% of theOropharyngeal flora of 5 – 70% of the
populationpopulation
– Significance in respiratory infectionSignificance in respiratory infection
Predisposing factorsPredisposing factors– Aspiration of upper airway secretions ( endogenous )Aspiration of upper airway secretions ( endogenous )– No person-person spread No person-person spread – Disturbed consciousness , general anaesthesia , Disturbed consciousness , general anaesthesia ,
convulsions , CVA , epilepsy , head trauma convulsions , CVA , epilepsy , head trauma – Prior LRT. VIRAL infection Prior LRT. VIRAL infection – Preexisting respiratory diseases , smoking Preexisting respiratory diseases , smoking
Chronic bronchitis , bronchogenic malignancy Chronic bronchitis , bronchogenic malignancy
– Chronic heart disease Chronic heart disease – Chronic renal disease ( nephrotic syndrome )Chronic renal disease ( nephrotic syndrome )– Chronic liver disease ( cirrhosis)Chronic liver disease ( cirrhosis)– Diabetes mellitus Diabetes mellitus – Old age , (extreme of age )Old age , (extreme of age )– Malnutrition , alcoholism Malnutrition , alcoholism
Specific deficiencies in host defence Specific deficiencies in host defence – HypogamaglobulinaemiaHypogamaglobulinaemia– Asplenia , hypospenism ( tuftsin )Asplenia , hypospenism ( tuftsin )– Homozygous sickle cell disease Homozygous sickle cell disease – Coeliac disease Coeliac disease – Multiple myeloma , leukaemia , lymphomasMultiple myeloma , leukaemia , lymphomas– Neutropenia Neutropenia – HIVHIV
Relative or absolute deficiency of opsonic Relative or absolute deficiency of opsonic antibody or inadequate manufacture of type antibody or inadequate manufacture of type specific antibody specific antibody
Diseases Diseases Respiratory tract infectionsRespiratory tract infections– Lobar pneumonia ( commonest cause of CAP )Lobar pneumonia ( commonest cause of CAP )– EmpyemaEmpyema– Otitis media (6 months – 3 yrs )Otitis media (6 months – 3 yrs )– MastoiditisMastoiditis– SinusitisSinusitis– Acute exacerbation of chronic bronchitis Acute exacerbation of chronic bronchitis
MeningitisMeningitisConjunctivitisConjunctivitisPeritonitis ( primary )Peritonitis ( primary )Bacteraemia ( 15 % of pneumonia )Bacteraemia ( 15 % of pneumonia )septicaemiasepticaemia
Clinical feature Clinical feature
Lobar pneumoniaLobar pneumonia– Sudden onsetSudden onset– FeverFever– rigorrigor– Cough , rusty sputum Cough , rusty sputum – Pleural painPleural pain– Signs of lobar consolidationSigns of lobar consolidation– Polymorphonuclear leucocytosis Polymorphonuclear leucocytosis – Empyema , pericarditis Empyema , pericarditis
MeningitisMeningitis– The most virulent pathogen of meningitisThe most virulent pathogen of meningitis– Mortality ( 20% )Mortality ( 20% )– Primary Primary – Complicate infections at other site ( lung )Complicate infections at other site ( lung )– Bacteraemia usually coexists Bacteraemia usually coexists – Bimodal incidence ( < 3 yr - > 45 yr )Bimodal incidence ( < 3 yr - > 45 yr )
Mortality Mortality
Age (> 65 yr ) Age (> 65 yr )
Preexisting diseasePreexisting disease
BacteraemiaBacteraemia
Serotype 3 , 7Serotype 3 , 7
Laboratory diagnosisLaboratory diagnosis
SpecimenSpecimen– SputumSputum– CSFCSF– SwabsSwabs– PusPus– Blood cultureBlood culture– Aspirate Aspirate
Microscopy Microscopy – Gram stained smear Gram stained smear
Gram-positive diplococci + pus cellsGram-positive diplococci + pus cells
cultureculture
Blood agar , chocolate agar + 10 % CO2Blood agar , chocolate agar + 10 % CO2
identificationidentification
Alph-haemolytic colonies Alph-haemolytic colonies Optochin sensitive Optochin sensitive Bile soluble Bile soluble
Sensitivity testingSensitivity testing– PenicillinPenicillin– susceptiblesusceptible
Sensitive Sensitive
– Nonsusceptible Nonsusceptible Intermediate Intermediate Resistant Resistant
– Ampicillin , amoxicillin Ampicillin , amoxicillin – Erythromycin Erythromycin – Ceftriaxone , cefuroxime Ceftriaxone , cefuroxime – ClindamycinClindamycin– Fluroquinolones Fluroquinolones – tetracyclinestetracyclines– Vancomycin Vancomycin
Treatment Treatment
MeningitisMeningitis– Parenteral ceftriaxone + vancomycinParenteral ceftriaxone + vancomycin
pneumoniapneumonia– Outpatients Outpatients
ErythromycinErythromycin
Amoxacillin – clavulanic acidAmoxacillin – clavulanic acid
Cefuroxime or ceftriaxone (IV) + oral Cefuroxime or ceftriaxone (IV) + oral b- lactamb- lactam
– Inpatients Inpatients Parenteral cefuroxime or ceftriaxone Parenteral cefuroxime or ceftriaxone
Prevention Prevention
23 polysaccharide vaccine 23 polysaccharide vaccine – Not effective in children < 2 yrsNot effective in children < 2 yrs– >65 yrs>65 yrs– Functional or anatomical asplenia Functional or anatomical asplenia – SCDSCD
7-valent – protein- conjugated vaccine7-valent – protein- conjugated vaccine– Children < 3 yrs Children < 3 yrs