Community-acquired pneumonia causes: Difference between revisions
Jump to navigation
Jump to search
Gerald Chi- (talk | contribs) No edit summary |
Gerald Chi- (talk | contribs) No edit summary |
||
| Line 2: | Line 2: | ||
{{Community-acquired pneumonia}} | {{Community-acquired pneumonia}} | ||
{{CMG}}; {{AE}} {{chetan}} | {{CMG}}; {{AE}} {{chetan}} | ||
==Overview== | ==Overview== | ||
Community-acquired pneumonia can be caused by viral, bacterial, and fungal organisms. The etiology depends upon various factors like age, immune status, geographical area, and comorbid conditions. | |||
==Causes== | ==Causes== | ||
* Newborn [[infant]]s, [[children]], and [[adult]]s are at risk for different spectrums of disease causing microorganisms. | * Newborn [[infant]]s, [[children]], and [[adult]]s are at risk for different spectrums of disease causing microorganisms. | ||
* In addition, adults with [[chronic (medicine)|chronic]] illnesses, who live in certain parts of the world, who reside in [[nursing home]]s, who have recently been treated with [[antibiotic]]s, or who are [[alcoholism|alcoholics]] are at risk for unique infections. | * In addition, adults with [[chronic (medicine)|chronic]] illnesses, who live in certain parts of the world, who reside in [[nursing home]]s, who have recently been treated with [[antibiotic]]s, or who are [[alcoholism|alcoholics]] are at risk for unique infections. | ||
===Infants=== | ===Infants=== | ||
====Source of Infection==== | ====Source of Infection==== | ||
* Aerosol | * Aerosol | ||
| Line 17: | Line 23: | ||
* Other bacterial causes in the newborn period include ''[[Listeria monocytogenes]]'' and [[tuberculosis]] | * Other bacterial causes in the newborn period include ''[[Listeria monocytogenes]]'' and [[tuberculosis]] | ||
* Viral causes like [[herpes simplex virus]] (most common) [[adenovirus]], [[mumps]], and [[enterovirus]] | * Viral causes like [[herpes simplex virus]] (most common) [[adenovirus]], [[mumps]], and [[enterovirus]] | ||
===Children=== | ===Children=== | ||
* For the most part, children older than one month are at risk for the same microorganisms as adults. | * For the most part, children older than one month are at risk for the same microorganisms as adults. | ||
* However, children less than five years are much less likely to have pneumonia caused by ''[[mycoplasma pneumoniae]]'', ''[[chlamydophila pneumoniae]]'', or ''[[Legionella|legionella pneumophila]]''.<ref name="Shachor-Meyouhas-2012">{{Cite journal | last1 = Shachor-Meyouhas | first1 = Y. | last2 = Arad-Cohen | first2 = N. | last3 = Zaidman | first3 = I. | last4 = Gefen | first4 = A. | last5 = Kassis | first5 = I. | title = [Legionella pneumonia in a child with leukemia]. | journal = Harefuah | volume = 151 | issue = 8 | pages = 479-82, 496 | month = Aug | year = 2012 | doi = | PMID = 23350295 }}</ref> | * However, children less than five years are much less likely to have pneumonia caused by ''[[mycoplasma pneumoniae]]'', ''[[chlamydophila pneumoniae]]'', or ''[[Legionella|legionella pneumophila]]''.<ref name="Shachor-Meyouhas-2012">{{Cite journal | last1 = Shachor-Meyouhas | first1 = Y. | last2 = Arad-Cohen | first2 = N. | last3 = Zaidman | first3 = I. | last4 = Gefen | first4 = A. | last5 = Kassis | first5 = I. | title = [Legionella pneumonia in a child with leukemia]. | journal = Harefuah | volume = 151 | issue = 8 | pages = 479-82, 496 | month = Aug | year = 2012 | doi = | PMID = 23350295 }}</ref> | ||
| Line 27: | Line 35: | ||
===Adults=== | ===Adults=== | ||
====Viruses==== | ====Viruses==== | ||
* Viruses cause 20% of CAP cases. | * Viruses cause 20% of CAP cases. | ||
* Common viruses are [[influenza]], [[parainfluenza]], [[respiratory syncytial virus]], [[metapneumovirus]], and [[adenovirus]]. | * Common viruses are [[influenza]], [[parainfluenza]], [[respiratory syncytial virus]], [[metapneumovirus]], and [[adenovirus]]. | ||
* Less common viruses include [[varicella|chicken pox]], [[SARS]], [[H5N1|avian flu]], and [[hantavirus]].{{ref|Roux}} | * Less common viruses include [[varicella|chicken pox]], [[SARS]], [[H5N1|avian flu]], and [[hantavirus]].{{ref|Roux}} | ||
====Atypical Organisms==== | ====Atypical Organisms==== | ||
*[[Mycoplasma pneumoniae]], [[chlamydophila pneumoniae]], and [[Legionella|legionella pneumophila]] are often grouped as atypical pneumonia. Community acquired pneumonia caused by these agents present insidiously, with a non-productive cough and prominent extra-pulmonary complaints, such as myalgias and diarrhea (lack the typical pneumonia symptoms of fever, cough, and sputum). | *[[Mycoplasma pneumoniae]], [[chlamydophila pneumoniae]], and [[Legionella|legionella pneumophila]] are often grouped as atypical pneumonia. Community acquired pneumonia caused by these agents present insidiously, with a non-productive cough and prominent extra-pulmonary complaints, such as myalgias and diarrhea (lack the typical pneumonia symptoms of fever, cough, and sputum). | ||
* Mycoplasma pneumonia is often called is "walking pneumonia." It is transmitted via respiratory droplets and is common among healthy individuals in close contact with one another, such as dormitories or military barracks. | * Mycoplasma pneumonia is often called is "walking pneumonia." It is transmitted via respiratory droplets and is common among healthy individuals in close contact with one another, such as dormitories or military barracks. | ||
| Line 37: | Line 49: | ||
====Streptococcus Pneumoniae==== | ====Streptococcus Pneumoniae==== | ||
* '''Streptococcus pneumoniae''' is the most common cause of [[community acquired pneumonia]]. | * '''Streptococcus pneumoniae''' is the most common cause of [[community acquired pneumonia]]. | ||
* Aspiration pneumonia is most commonly caused by anaerobic organisms. | * Aspiration pneumonia is most commonly caused by anaerobic organisms. | ||
| Line 43: | Line 56: | ||
* Current strains of "drug resistant Streptococcus pneumoniae" or DRSP are common, accounting for twenty percent of all streptococcus pneumoniae infections. | * Current strains of "drug resistant Streptococcus pneumoniae" or DRSP are common, accounting for twenty percent of all streptococcus pneumoniae infections. | ||
* Adults with risk factors for DRSP including being older than 65, having exposure to children in [[day care]], alcoholism, other severe underlying disease, or recent treatment with antibiotics should initially be treated with antibiotics effective against DRSP.{{ref|Ruhe}} | * Adults with risk factors for DRSP including being older than 65, having exposure to children in [[day care]], alcoholism, other severe underlying disease, or recent treatment with antibiotics should initially be treated with antibiotics effective against DRSP.{{ref|Ruhe}} | ||
====Hemophilus Influenzae==== | ====Hemophilus Influenzae==== | ||
* Another common bacterial cause of CAP. | * Another common bacterial cause of CAP. | ||
* First discovered in [[1892]], it was initially believed to be the cause of influenza because it commonly causes CAP in people who have suffered recent lung damage from viral pneumonia. | * First discovered in [[1892]], it was initially believed to be the cause of influenza because it commonly causes CAP in people who have suffered recent lung damage from viral pneumonia. | ||
====Enteric Gram Negative Bacteria==== | ====Enteric Gram Negative Bacteria==== | ||
* Involve colonic bacteria E.coli and K.pneumonia | * Involve colonic bacteria E.coli and K.pneumonia | ||
* Adults with risk factors for infection, which include living in a [[nursing home]], serious [[heart disease|heart]] and [[lung disease]], and recent antibiotic use should initially be treated with antibiotics effective against Enteric Gram negative bacteria. | * Adults with risk factors for infection, which include living in a [[nursing home]], serious [[heart disease|heart]] and [[lung disease]], and recent antibiotic use should initially be treated with antibiotics effective against Enteric Gram negative bacteria. | ||
====Pseudomonas Aeruginosa==== | ====Pseudomonas Aeruginosa==== | ||
* Uncommon cause of CAP, but it is a particularly difficult bacteria to treat. | * Uncommon cause of CAP, but it is a particularly difficult bacteria to treat. | ||
* Individuals who are malnourished, have [[bronchiectasis]], are on [[corticosteroids]], or have recently had strong antibiotics for a week or more, should initially be treated with antibiotics effective against [[Pseudomonas aeruginosa]].{{ref|Lieberman}} | * Individuals who are malnourished, have [[bronchiectasis]], are on [[corticosteroids]], or have recently had strong antibiotics for a week or more, should initially be treated with antibiotics effective against [[Pseudomonas aeruginosa]].{{ref|Lieberman}} | ||
====Special Situations==== | ====Special Situations==== | ||
* Coccidioides are common in southwestern US. | * Coccidioides are common in southwestern US. | ||
* Anaerobic infection is common in alcoholics. Pneumococcal pneumonia remains the most common cause of CAP in alcoholics too. | * Anaerobic infection is common in alcoholics. Pneumococcal pneumonia remains the most common cause of CAP in alcoholics too. | ||
| Line 62: | Line 82: | ||
* [[S. pneumonia]], [[H.influenza]], and [[mycobacterium tuberculosis]] are common pathogens in early stages of HIV, whereas, [[P.jiroveci]], [[histoplasma]], and [[cryptococcus]] are commonly seen in late stages HIV. | * [[S. pneumonia]], [[H.influenza]], and [[mycobacterium tuberculosis]] are common pathogens in early stages of HIV, whereas, [[P.jiroveci]], [[histoplasma]], and [[cryptococcus]] are commonly seen in late stages HIV. | ||
* In patients with structural lung disease such as [[bronchiectasis]] and [[cystic fibrosis]], [[pseudomonas aeruginosa]], [[Burkholderia cepacia]] (pseudomonas), and [[staphylococcus aureus]] are the common pathogens involved. | * In patients with structural lung disease such as [[bronchiectasis]] and [[cystic fibrosis]], [[pseudomonas aeruginosa]], [[Burkholderia cepacia]] (pseudomonas), and [[staphylococcus aureus]] are the common pathogens involved. | ||
==Aspiration Pneumonia Causes== | ==Aspiration Pneumonia Causes== | ||
* Incompetent [[swallowing]] mechanism, such as in neurological disease (a common cause being [[cerebrovascular accident|strokes]]) or while a person is [[Drunkenness|intoxicated]]. | * Incompetent [[swallowing]] mechanism, such as in neurological disease (a common cause being [[cerebrovascular accident|strokes]]) or while a person is [[Drunkenness|intoxicated]]. | ||
* [[Iatrogenic]] causes such as [[general anaesthesia]] for an [[Surgery|operation]]. Patients are therefore instructed to be [[nil per os]] (NPO) for at least four hours before surgery. | * [[Iatrogenic]] causes such as [[general anaesthesia]] for an [[Surgery|operation]]. Patients are therefore instructed to be [[nil per os]] (NPO) for at least four hours before surgery. | ||
* Whether aspiration pneumonia represents a true bacterial infection or a chemical inflammatory process remains the subject of significant controversy. | * Whether aspiration pneumonia represents a true bacterial infection or a chemical inflammatory process remains the subject of significant controversy. | ||
==Infectious Diseases Society of America/American Thoracic Society consensus statement on common etiologies of community-acquired pneumonia in adults. <ref name="pmid17278083">{{cite journal |author=Mandell LA, Wunderink RG, Anzueto A, Bartlett JG, Campbell GD, Dean NC, Dowell SF, File TM, Musher DM, Niederman MS, Torres A, Whitney CG |title=Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults |journal=[[Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America]] |volume=44 Suppl 2 |issue= |pages=S27–72 |year=2007 |month=March |pmid=17278083 |doi=10.1086/511159 |url=http://www.cid.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17278083 |accessdate=2012-09-06}}</ref> (DO NOT EDIT)== | ==Infectious Diseases Society of America/American Thoracic Society consensus statement on common etiologies of community-acquired pneumonia in adults.<ref name="pmid17278083">{{cite journal |author=Mandell LA, Wunderink RG, Anzueto A, Bartlett JG, Campbell GD, Dean NC, Dowell SF, File TM, Musher DM, Niederman MS, Torres A, Whitney CG |title=Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults |journal=[[Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America]] |volume=44 Suppl 2 |issue= |pages=S27–72 |year=2007 |month=March |pmid=17278083 |doi=10.1086/511159 |url=http://www.cid.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17278083 |accessdate=2012-09-06}}</ref> (DO NOT EDIT)== | ||
===Outpatient=== | ===Outpatient=== | ||
* [[Streptococcus pneumoniae]] | * [[Streptococcus pneumoniae]] | ||
* [[Mycoplasma pneumoniae]] | * [[Mycoplasma pneumoniae]] | ||
| Line 75: | Line 98: | ||
* [[Chlamydophila pneumoniae]] | * [[Chlamydophila pneumoniae]] | ||
* [[Respiratory viruses]] | * [[Respiratory viruses]] | ||
===Inpatient (non-ICU)=== | ===Inpatient (non-ICU)=== | ||
* S. pneumoniae | * S. pneumoniae | ||
* M. pneumoniae | * M. pneumoniae | ||
| Line 84: | Line 109: | ||
* Respiratory viruses | * Respiratory viruses | ||
* Yersinia enterocolitica<ref name="Wong-2013">{{Cite journal | last1 = Wong | first1 = KK. | last2 = Fistek | first2 = M. | last3 = Watkins | first3 = RR. | title = Community-acquired pneumonia caused by Yersinia enterocolitica in an immunocompetent patient. | journal = J Med Microbiol | volume = 62 | issue = Pt 4 | pages = 650-1 | month = Apr | year = 2013 | doi = 10.1099/jmm.0.053488-0 | PMID = 23242642 }}</ref> | * Yersinia enterocolitica<ref name="Wong-2013">{{Cite journal | last1 = Wong | first1 = KK. | last2 = Fistek | first2 = M. | last3 = Watkins | first3 = RR. | title = Community-acquired pneumonia caused by Yersinia enterocolitica in an immunocompetent patient. | journal = J Med Microbiol | volume = 62 | issue = Pt 4 | pages = 650-1 | month = Apr | year = 2013 | doi = 10.1099/jmm.0.053488-0 | PMID = 23242642 }}</ref> | ||
===Inpatient (ICU)=== | ===Inpatient (ICU)=== | ||
* S. pneumoniae | * S. pneumoniae | ||
* Staphylococcus aureus | * Staphylococcus aureus | ||
| Line 90: | Line 117: | ||
* Gram-negative bacilli | * Gram-negative bacilli | ||
* H. influenzae | * H. influenzae | ||
*Acinetobacter baumannii<ref name="Oh-2013">{{Cite journal | last1 = Oh | first1 = YJ. | last2 = Song | first2 = SH. | last3 = Baik | first3 = SH. | last4 = Lee | first4 = HH. | last5 = Han | first5 = IM. | last6 = Oh | first6 = DH. | title = A case of fulminant community-acquired Acinetobacter baumannii pneumonia in Korea. | journal = Korean J Intern Med | volume = 28 | issue = 4 | pages = 486-90 | month = Jul | year = 2013 | doi = 10.3904/kjim.2013.28.4.486 | PMID = 23864808 }}</ref> | * Acinetobacter baumannii<ref name="Oh-2013">{{Cite journal | last1 = Oh | first1 = YJ. | last2 = Song | first2 = SH. | last3 = Baik | first3 = SH. | last4 = Lee | first4 = HH. | last5 = Han | first5 = IM. | last6 = Oh | first6 = DH. | title = A case of fulminant community-acquired Acinetobacter baumannii pneumonia in Korea. | journal = Korean J Intern Med | volume = 28 | issue = 4 | pages = 486-90 | month = Jul | year = 2013 | doi = 10.3904/kjim.2013.28.4.486 | PMID = 23864808 }}</ref> | ||
==References== | ==References== | ||
{{Reflist|2}} | {{Reflist|2}} | ||
Revision as of 22:36, 17 February 2014
|
Community-Acquired Pneumonia Microchapters |
|
Differentiating Community-acquired pneumonia from other Diseases |
|
Diagnosis |
|
Treatment |
|
Case Studies |
|
Community-acquired pneumonia causes On the Web |
|
American Roentgen Ray Society Images of Community-acquired pneumonia causes |
|
Directions to Hospitals Treating Community-acquired pneumonia |
|
Risk calculators and risk factors for Community-acquired pneumonia causes |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Chetan Lokhande, M.B.B.S [2]
Overview
Community-acquired pneumonia can be caused by viral, bacterial, and fungal organisms. The etiology depends upon various factors like age, immune status, geographical area, and comorbid conditions.
Causes
- Newborn infants, children, and adults are at risk for different spectrums of disease causing microorganisms.
- In addition, adults with chronic illnesses, who live in certain parts of the world, who reside in nursing homes, who have recently been treated with antibiotics, or who are alcoholics are at risk for unique infections.
Infants
Source of Infection
- Aerosol
Newborn
- GBS causes at least 50% of cases of CAP in the first week of life.[3]
- Other bacterial causes in the newborn period include Listeria monocytogenes and tuberculosis
- Viral causes like herpes simplex virus (most common) adenovirus, mumps, and enterovirus
Children
- For the most part, children older than one month are at risk for the same microorganisms as adults.
- However, children less than five years are much less likely to have pneumonia caused by mycoplasma pneumoniae, chlamydophila pneumoniae, or legionella pneumophila.[1]
- In contrast, older children and teenagers are more likely to acquire mycoplasma pneumoniae and chlamydophila pneumoniae than adults.[4]
- A unique cause of CAP in this group is chlamydia trachomatis, which is acquired during birth but does not cause pneumonia until 2-4 weeks later.
- Common viruses include respiratory syncytial virus (RSV), metapneumovirus, adenovirus, parainfluenza, influenza, and rhinovirus.
- RSV in particular is a common source of illness and hospitalization.[5]
- Fungi and parasites are not typically encountered in otherwise healthy infants, though maternally-derived syphilis can be a cause of CAP in this age group.
Adults
Viruses
- Viruses cause 20% of CAP cases.
- Common viruses are influenza, parainfluenza, respiratory syncytial virus, metapneumovirus, and adenovirus.
- Less common viruses include chicken pox, SARS, avian flu, and hantavirus.[6]
Atypical Organisms
- Mycoplasma pneumoniae, chlamydophila pneumoniae, and legionella pneumophila are often grouped as atypical pneumonia. Community acquired pneumonia caused by these agents present insidiously, with a non-productive cough and prominent extra-pulmonary complaints, such as myalgias and diarrhea (lack the typical pneumonia symptoms of fever, cough, and sputum).
- Mycoplasma pneumonia is often called is "walking pneumonia." It is transmitted via respiratory droplets and is common among healthy individuals in close contact with one another, such as dormitories or military barracks.
- Atypical organisms are more difficult to grow, respond to different antibiotics, and were discovered more recently than the typical bacteria discovered in the early twentieth century.
Streptococcus Pneumoniae
- Streptococcus pneumoniae is the most common cause of community acquired pneumonia.
- Aspiration pneumonia is most commonly caused by anaerobic organisms.
- Prior to the development of antibiotics and vaccination, it was a leading cause of death.
- Traditionally, it was highly sensitive to penicillin, but during the 1970s resistance to multiple antibiotics began to develop.
- Current strains of "drug resistant Streptococcus pneumoniae" or DRSP are common, accounting for twenty percent of all streptococcus pneumoniae infections.
- Adults with risk factors for DRSP including being older than 65, having exposure to children in day care, alcoholism, other severe underlying disease, or recent treatment with antibiotics should initially be treated with antibiotics effective against DRSP.[7]
Hemophilus Influenzae
- Another common bacterial cause of CAP.
- First discovered in 1892, it was initially believed to be the cause of influenza because it commonly causes CAP in people who have suffered recent lung damage from viral pneumonia.
Enteric Gram Negative Bacteria
- Involve colonic bacteria E.coli and K.pneumonia
- Adults with risk factors for infection, which include living in a nursing home, serious heart and lung disease, and recent antibiotic use should initially be treated with antibiotics effective against Enteric Gram negative bacteria.
Pseudomonas Aeruginosa
- Uncommon cause of CAP, but it is a particularly difficult bacteria to treat.
- Individuals who are malnourished, have bronchiectasis, are on corticosteroids, or have recently had strong antibiotics for a week or more, should initially be treated with antibiotics effective against Pseudomonas aeruginosa.[8]
Special Situations
- Coccidioides are common in southwestern US.
- Anaerobic infection is common in alcoholics. Pneumococcal pneumonia remains the most common cause of CAP in alcoholics too.
- Psittacosis (due to Chlamydophila psittaci) should be considered in the patient with exposure to birds or bird droppings.
- Anaerobes are common in patients with poor dental hygiene, and a suspected large volume of aspiration.
- Streptococcus pneumoniae, H.influenza, moraxella catarrhalis, and legionella species are the common causes of community acquired pneumonia in chronic obstructive pulmonary disorders and smokers.
- S. pneumonia, gram negative bacilli, H.influenza, staphylococcus aureus, anaerobes, and chlamydiae pneumonia are more common in nursing home residents.
- S. pneumonia, H.influenza, and mycobacterium tuberculosis are common pathogens in early stages of HIV, whereas, P.jiroveci, histoplasma, and cryptococcus are commonly seen in late stages HIV.
- In patients with structural lung disease such as bronchiectasis and cystic fibrosis, pseudomonas aeruginosa, Burkholderia cepacia (pseudomonas), and staphylococcus aureus are the common pathogens involved.
Aspiration Pneumonia Causes
- Incompetent swallowing mechanism, such as in neurological disease (a common cause being strokes) or while a person is intoxicated.
- Iatrogenic causes such as general anaesthesia for an operation. Patients are therefore instructed to be nil per os (NPO) for at least four hours before surgery.
- Whether aspiration pneumonia represents a true bacterial infection or a chemical inflammatory process remains the subject of significant controversy.
Infectious Diseases Society of America/American Thoracic Society consensus statement on common etiologies of community-acquired pneumonia in adults.[2] (DO NOT EDIT)
Outpatient
- Streptococcus pneumoniae
- Mycoplasma pneumoniae
- Haemophilus influenzae
- Chlamydophila pneumoniae
- Respiratory viruses
Inpatient (non-ICU)
- S. pneumoniae
- M. pneumoniae
- C. pneumoniae
- H. influenzae
- Legionella species
- Aspiration
- Respiratory viruses
- Yersinia enterocolitica[3]
Inpatient (ICU)
- S. pneumoniae
- Staphylococcus aureus
- Legionella species
- Gram-negative bacilli
- H. influenzae
- Acinetobacter baumannii[4]
References
- ↑ Shachor-Meyouhas, Y.; Arad-Cohen, N.; Zaidman, I.; Gefen, A.; Kassis, I. (2012). "[Legionella pneumonia in a child with leukemia]". Harefuah. 151 (8): 479–82, 496. PMID 23350295. Unknown parameter
|month=ignored (help) - ↑ Mandell LA, Wunderink RG, Anzueto A, Bartlett JG, Campbell GD, Dean NC, Dowell SF, File TM, Musher DM, Niederman MS, Torres A, Whitney CG (2007). "Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults". Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America. 44 Suppl 2: S27–72. doi:10.1086/511159. PMID 17278083. Retrieved 2012-09-06. Unknown parameter
|month=ignored (help) - ↑ Wong, KK.; Fistek, M.; Watkins, RR. (2013). "Community-acquired pneumonia caused by Yersinia enterocolitica in an immunocompetent patient". J Med Microbiol. 62 (Pt 4): 650–1. doi:10.1099/jmm.0.053488-0. PMID 23242642. Unknown parameter
|month=ignored (help) - ↑ Oh, YJ.; Song, SH.; Baik, SH.; Lee, HH.; Han, IM.; Oh, DH. (2013). "A case of fulminant community-acquired Acinetobacter baumannii pneumonia in Korea". Korean J Intern Med. 28 (4): 486–90. doi:10.3904/kjim.2013.28.4.486. PMID 23864808. Unknown parameter
|month=ignored (help)