1. The three bacteria that may be implicated in the given case are Staphylococcus aureus, Haemophilus parainfluenzae, Cardiobacterium hominis . These organisms generally occur in the saliva as normal flora. However, drug users who lick the blood on syringes ingest them and thus, they can casue polymicrobial endocarditis. 2. Cardiobacterium hominis is Gram negative bacillus that occurs as normal flora of mouth and upper respiratory tract. The bacterium is grouped into HACEK group. The organism can cause inflammation of heart valves. It produces beta lactamases Haemophilus parainfluenzae: Gram negative, pleomorphic, facultative anaerobes. The organism is mostly assocaited with upper respiratory tract infections and mitral valve inflammation. The organism is generally found in coinfection with Streptococcus. Cardiobacterium hominis: It is a Gram negative bacillus of HACEK group. It is part of normal flora of upper respiratory tract and mouth. These organisms are generally harmless, and occur as secondary infection. When there is a disturbance to the mucosal surface, they gain access and enter the tissues. They cause infections at abnormal tissues of heart like damages valves, in particular. They initiate an inflammatory response. 3. The organisms are normally present as flora in the host. The patient acquired these bacteria due to the use of syringe drugs. Licking of the blood on the syringe, and sterilizing the syringe by licking makes the organism enter the sytem. Solution 1. The three bacteria that may be implicated in the given case are Staphylococcus aureus, Haemophilus parainfluenzae, Cardiobacterium hominis . These organisms generally occur in the saliva as normal flora. However, drug users who lick the blood on syringes ingest them and thus, they can casue polymicrobial endocarditis. 2. Cardiobacterium hominis is Gram negative bacillus that occurs as normal flora of mouth and upper respiratory tract. The bacterium is grouped into HACEK group. The organism can cause inflammation of heart valves. It produces beta lactamases Haemophilus parainfluenzae: Gram negative, pleomorphic, facultative anaerobes. The organism is mostly assocaited with upper respiratory tract infections and mitral valve inflammation. The organism is generally found in coinfection with Streptococcus. Cardiobacterium hominis: It is a Gram negative bacillus of HACEK group. It is part of normal flora of upper respiratory tract and mouth. These organisms are generally harmless, and occur as secondary infection. When there is a disturbance to the mucosal surface, they gain access and enter the tissues. They cause infections at abnormal tissues of heart like damages valves, in particular. They initiate an inflammatory response. 3. The organisms are normally present as flora in the host. The patient acquired these bacteria due to the use of syringe drugs. Licking of the blood on the syringe, and sterilizing the syringe by licking makes the organism enter the sytem..

1. 1. The three bacteria that may be implicated in the given case are Staphylococcus aureus,
Haemophilus parainfluenzae, Cardiobacterium hominis . These organisms generally occur in the
saliva as normal flora. However, drug users who lick the blood on syringes ingest them and thus,
they can casue polymicrobial endocarditis.
2. Cardiobacterium hominis is Gram negative bacillus that occurs as normal flora of mouth and
upper respiratory tract. The bacterium is grouped into HACEK group. The organism can cause
inflammation of heart valves. It produces beta lactamases
Haemophilus parainfluenzae: Gram negative, pleomorphic, facultative anaerobes. The organism
is mostly assocaited with upper respiratory tract infections and mitral valve inflammation. The
organism is generally found in coinfection with Streptococcus.
Cardiobacterium hominis: It is a Gram negative bacillus of HACEK group. It is part of normal
flora of upper respiratory tract and mouth.
These organisms are generally harmless, and occur as secondary infection. When there is a
disturbance to the mucosal surface, they gain access and enter the tissues. They cause infections
at abnormal tissues of heart like damages valves, in particular. They initiate an inflammatory
response.
3. The organisms are normally present as flora in the host. The patient acquired these bacteria
due to the use of syringe drugs. Licking of the blood on the syringe, and sterilizing the syringe by
licking makes the organism enter the sytem.
Solution
1. The three bacteria that may be implicated in the given case are Staphylococcus aureus,
Haemophilus parainfluenzae, Cardiobacterium hominis . These organisms generally occur in the
saliva as normal flora. However, drug users who lick the blood on syringes ingest them and thus,
they can casue polymicrobial endocarditis.
2. Cardiobacterium hominis is Gram negative bacillus that occurs as normal flora of mouth and
upper respiratory tract. The bacterium is grouped into HACEK group. The organism can cause
inflammation of heart valves. It produces beta lactamases
Haemophilus parainfluenzae: Gram negative, pleomorphic, facultative anaerobes. The organism
is mostly assocaited with upper respiratory tract infections and mitral valve inflammation. The
organism is generally found in coinfection with Streptococcus.
Cardiobacterium hominis: It is a Gram negative bacillus of HACEK group. It is part of normal
flora of upper respiratory tract and mouth.
These organisms are generally harmless, and occur as secondary infection. When there is a

2. disturbance to the mucosal surface, they gain access and enter the tissues. They cause infections
at abnormal tissues of heart like damages valves, in particular. They initiate an inflammatory
response.
3. The organisms are normally present as flora in the host. The patient acquired these bacteria
due to the use of syringe drugs. Licking of the blood on the syringe, and sterilizing the syringe by
licking makes the organism enter the sytem.