Monday, December 3, 2007
MMIC PBL 1
Name: Wong Fei Hong (Case 5)
Sex: Male
Age: 37 years old
Type of Specimen: Wound swab
Clinical diagnosis
Symptoms: Fever, swelling around operation wound
Diagnosis: Wound infection
Interpretation of symptoms
Fever:
Fever is a non-specific clinical manifestation for a wide range of viral or bacterial infections. In the case of bacterial infections, the effects of endotoxins from gram-negative bacteria, lead to the release of endogenous pyrogen from macrophage and cause fever. In addition, the release of various exotoxins from gram-positive bacteria can also cause fever. [1]
Swelling around operation wound:
A swell is a result of increased extravascular fluid and phagocyte infiltration to the damaged area. The swell around operation wound indicates localised inflammatory response due to the presence of bacteria at the site of wound. Thus, swab is collected and sent quickly for investigation. [1]
Interpretation of diagnosis
Wound infection:
A wound is generally defined as the break the continuity of the skin, which allows pathogenic microorganisms to gain access to tissues and cause infection. Operation wound infection known as surgical site infection (SSI) can be classified into 3 types, namely, superficial incisional SSI, deep incisional SSI, and organ SSI. [3]
Picture: http://www.emedicine.com/med/images/Large/22552255ppt1.jpg
Mode of transmission
Causative agents could be transmitted from non-human source such as fomite (i.e. towel), soil, animal, and also from the normal flora of the host, which lead to the symptoms described above. [1]
Possible causative agents for wound infection [1, 2]
Streptococci Species (facultative anaerobe, gram-positive cocci)
-Enterococcus faecalis
-Streptococcus pyogenes
Staphylococcus aureus (facultative anaerobe, gram-positive cocci)
Bacillus anthracis (aerobic, gram-positive rod, spore-forming)
Clostridium species (anaerobic, gram-positive rod, spore forming)
-Clostridium perfringens
-Clostridium tetani
Pseudomonas aeruginosa (aerobic, gram-negative rod)
Enterobacteriaceae species (facultative anaerobe, gram-negative rod)
-Escherichia coli
-Enterobacter
-Serratia marcescens
-Proteus mirabilis
-Klebsiella pneumoniae
Shortlisted
Enterococcus faecalis [2]
Reasons for inclusion: E. faecalis is part of the normal flora in colon but can cause serious disease when introduced into other part of the body. Patient could have been acquired the bacteria during his stay in hospital, or due to poor personal hygiene which led to wound infection.
Streptococcus pyogenes [2]
Reason for inclusion: S. Pyogenes is a common causative agent of skin infection for patient with skin trauma such as operation wound. Symptoms of infection include fever, inflammation around site of wound infection.
Staphylococcus aureus [1]
Reason for inclusion: Failure to follow aseptic surgical procedures could have lead to S. Aureus wound infection.
Bacillus anthracis [1]
Reason for inclusion: Spores could have entered wound from the soil;or animal products such as bristles, hives or wool.
Clostridium perfringens [1]
Reason for inclusion: Is present in normal flora of human colon, or soil, which could enter wound due to poor hygiene.
Clostridium tetani [1]
Reason for exclusion: Specific clinical feature such as lockjaw is absent.
Pseudomonas aeruginosa [2]
Reason for inclusion: P. aeruginosa is an opportunistic pathogen that cause wound infection, thus the assumption would be that patient is immunocompromised.
Enterobacteriaceae species [2]
-Escherichia coli
-Enterobacter
-Serratia marcescens
-Proteus mirabilis
-Klebsiella pneumoniae
Reason for inclusion: The Enterobacteriaceae species are opportunistic pathogens acquired from hospital,which can cause surgical wound infection. Similarly, the assumption would be that patient is immunocompromised.
P.S: In blog 2, I'll elaborate on various biochemical tests for differential/ confirmatory diagnosis, as well as antibody susceptibility test.
References:
1)Levinson, W. (2006). Review of Medical Microbiology and Immunology. San Francisco,California: Lange Medical Books/ McGraw-Hill Medical Publishing Division
2)www.textbookofbacteriology.net>search
3)med>topic2422/">http://www.emedicine.com>med>topic2422
Foo Yong Yang
TG02
0503196H
Sex: Male
Age: 37 years old
Type of Specimen: Wound swab
Clinical diagnosis
Symptoms: Fever, swelling around operation wound
Diagnosis: Wound infection
Interpretation of symptoms
Fever:
Fever is a non-specific clinical manifestation for a wide range of viral or bacterial infections. In the case of bacterial infections, the effects of endotoxins from gram-negative bacteria, lead to the release of endogenous pyrogen from macrophage and cause fever. In addition, the release of various exotoxins from gram-positive bacteria can also cause fever. [1]
Swelling around operation wound:
A swell is a result of increased extravascular fluid and phagocyte infiltration to the damaged area. The swell around operation wound indicates localised inflammatory response due to the presence of bacteria at the site of wound. Thus, swab is collected and sent quickly for investigation. [1]
Interpretation of diagnosis
Wound infection:
A wound is generally defined as the break the continuity of the skin, which allows pathogenic microorganisms to gain access to tissues and cause infection. Operation wound infection known as surgical site infection (SSI) can be classified into 3 types, namely, superficial incisional SSI, deep incisional SSI, and organ SSI. [3]
Picture: http://www.emedicine.com/med/images/Large/22552255ppt1.jpg
Mode of transmission
Causative agents could be transmitted from non-human source such as fomite (i.e. towel), soil, animal, and also from the normal flora of the host, which lead to the symptoms described above. [1]
Possible causative agents for wound infection [1, 2]
Streptococci Species (facultative anaerobe, gram-positive cocci)
-Enterococcus faecalis
-Streptococcus pyogenes
Staphylococcus aureus (facultative anaerobe, gram-positive cocci)
Bacillus anthracis (aerobic, gram-positive rod, spore-forming)
Clostridium species (anaerobic, gram-positive rod, spore forming)
-Clostridium perfringens
-Clostridium tetani
Pseudomonas aeruginosa (aerobic, gram-negative rod)
Enterobacteriaceae species (facultative anaerobe, gram-negative rod)
-Escherichia coli
-Enterobacter
-Serratia marcescens
-Proteus mirabilis
-Klebsiella pneumoniae
Shortlisted
Enterococcus faecalis [2]
Reasons for inclusion: E. faecalis is part of the normal flora in colon but can cause serious disease when introduced into other part of the body. Patient could have been acquired the bacteria during his stay in hospital, or due to poor personal hygiene which led to wound infection.
Streptococcus pyogenes [2]
Reason for inclusion: S. Pyogenes is a common causative agent of skin infection for patient with skin trauma such as operation wound. Symptoms of infection include fever, inflammation around site of wound infection.
Staphylococcus aureus [1]
Reason for inclusion: Failure to follow aseptic surgical procedures could have lead to S. Aureus wound infection.
Bacillus anthracis [1]
Reason for inclusion: Spores could have entered wound from the soil;or animal products such as bristles, hives or wool.
Clostridium perfringens [1]
Reason for inclusion: Is present in normal flora of human colon, or soil, which could enter wound due to poor hygiene.
Clostridium tetani [1]
Reason for exclusion: Specific clinical feature such as lockjaw is absent.
Pseudomonas aeruginosa [2]
Reason for inclusion: P. aeruginosa is an opportunistic pathogen that cause wound infection, thus the assumption would be that patient is immunocompromised.
Enterobacteriaceae species [2]
-Escherichia coli
-Enterobacter
-Serratia marcescens
-Proteus mirabilis
-Klebsiella pneumoniae
Reason for inclusion: The Enterobacteriaceae species are opportunistic pathogens acquired from hospital,which can cause surgical wound infection. Similarly, the assumption would be that patient is immunocompromised.
P.S: In blog 2, I'll elaborate on various biochemical tests for differential/ confirmatory diagnosis, as well as antibody susceptibility test.
References:
1)Levinson, W. (2006). Review of Medical Microbiology and Immunology. San Francisco,California: Lange Medical Books/ McGraw-Hill Medical Publishing Division
2)www.textbookofbacteriology.net>search
3)med>topic2422/">http://www.emedicine.com>med>topic2422
Foo Yong Yang
TG02
0503196H
# posted by Star team @ 5:34 AM 
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