Rhodococcus hoagii: Difference between revisions
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Rhodococcus hoagii
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===Microbiology=== |
===Microbiology=== |
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− | *Facultative intracellular, non-spore-forming, [[Stain::Gram-positive]], weakly acid-fast [[ |
+ | *Facultative intracellular, non-spore-forming, [[Stain::Gram-positive]], weakly acid-fast [[Shape::coccobacillus]] |
+ | **More coccoid when grown on solid media, and more bacillary with varying lengths (often beaded) when grown in liquid media |
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+ | *Within the family [[Nocardiaceae]] and order [[Actinomycetes]] |
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+ | *Obligate aerobic and facultatively intracellular |
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*Found in dry and dusty soil |
*Found in dry and dusty soil |
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*Makes red pigment, hence the name |
*Makes red pigment, hence the name |
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− | *Member of the actinomycetes group |
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===Epidemiology=== |
===Epidemiology=== |
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− | *Infects domesticated animals |
+ | *Infects domesticated animals: [[Horses]] (and in foals it causes pneumonia), [[Goats]], [[Pigs]], [[Sheep]], and [[Cattle]] |
+ | *Most commonly infects people with cell-mediated immunodeficiency, particularly [[HIV]], with or without a notable infectious exposure |
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− | **[[Horses]], and in foals it causes pneumonia |
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+ | |||
− | **[[Goats]] |
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+ | ===Risk Factors=== |
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− | **[[Pigs]] |
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+ | |||
− | **[[Sheep]] |
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+ | *HIV accounts for 65% of cases |
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− | **[[Cattle]] |
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+ | *Solid organ and hematopoietic stem cell transplantation |
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− | *Can infect immunocompromised people (HIV, etc) |
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+ | *Diabetes |
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+ | *Alcohol abuse |
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+ | *Chronic renal failure |
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+ | *Leukemia, lymphoma, lung cancer |
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+ | *Sarcoidosis |
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+ | *Preterm infants |
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==Clinical Manifestations== |
==Clinical Manifestations== |
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*[[Necrotizing pneumonia]] is usual presentation, as well as [[Lung nodules|nodules]], [[Cavitary lung disease|cavitation]], [[pleural effusion]], and [[lung abscess]] |
*[[Necrotizing pneumonia]] is usual presentation, as well as [[Lung nodules|nodules]], [[Cavitary lung disease|cavitation]], [[pleural effusion]], and [[lung abscess]] |
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+ | **Typically subacute onset with fever, cough, and fatigue, as well as pleuritic chest pain |
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*Specifically in immunocompromised patients, it can cause a [[cavitary lung disease]] and is on the differential with [[Mycobacterium species|mycobacteria]] and [[nocardiosis]] |
*Specifically in immunocompromised patients, it can cause a [[cavitary lung disease]] and is on the differential with [[Mycobacterium species|mycobacteria]] and [[nocardiosis]] |
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+ | *Extrapulmonary disease can occur with or without pulmonary involvement |
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+ | **In conjunction with other infections, can have abscesses in liver, spleen, thyroid, kidney, psoas, bone, prostate, intraabdominal cavity, and paraspinous tissue |
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+ | *Extrapulmonary disease without pulmonary involvement has three main presentations: |
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+ | **Localized infection following traumatic inoculation, causing wound infection, traumatic septic arthritis, or endophthalmitis |
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+ | **Isolated bacteremia with fever, typically recently after chemotherapy causing neutropenia |
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+ | **Gastrointestional inoculation followed by lymphatic dissemination, causing peritonitis, pelvic masses, and mesenteric adenitis |
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+ | **Others include otitis media with mastoiditis, colonic polyp infection, and osteomyelitis |
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+ | |||
+ | == Diagnosis == |
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+ | |||
+ | * May be misidentified as [[Corynebacterium]] in blood culture or [[Kocuria]] on Vitek |
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− | == |
+ | ==Management== |
+ | *Recommend using at least two agents given increasing rates of resistance |
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⚫ | |||
+ | **First-line: combination of [[macrolide]] or [[fluoroquinolone]] plus [[rifampin]] |
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⚫ | |||
+ | **First-line: combination of [[macrolide]] or [[fluoroquinolone]] plus two of: [[vancomycin]], [[imipenem]], [[linezolid]], or an [[aminoglycoside]] |
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+ | **Doses are: |
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+ | ***[[Azithromycin]] 500 mg PO/IV once followed by 250 mg PO/IV daily |
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+ | ***Fluoroquinolones: [[moxifloxacin]] 400 mg PO daily (preferred), [[levofloxacin]] 500 mg PO daily, or [[ciprofloxacin]] 750 mg PO BID |
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+ | ***[[Rifampin]] 600 mg PO once daily |
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+ | **Increasing resistance to [[doxycycline]], [[rifampin]], and [[TMP-SMX]] |
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⚫ | |||
⚫ | |||
[[Category:Gram-positive bacteria]] |
[[Category:Gram-positive bacteria]] |
Latest revision as of 12:49, 31 August 2022
Background
Microbiology
- Facultative intracellular, non-spore-forming, Gram-positive, weakly acid-fast coccobacillus
- More coccoid when grown on solid media, and more bacillary with varying lengths (often beaded) when grown in liquid media
- Within the family Nocardiaceae and order Actinomycetes
- Obligate aerobic and facultatively intracellular
- Found in dry and dusty soil
- Makes red pigment, hence the name
Epidemiology
- Infects domesticated animals: Horses (and in foals it causes pneumonia), Goats, Pigs, Sheep, and Cattle
- Most commonly infects people with cell-mediated immunodeficiency, particularly HIV, with or without a notable infectious exposure
Risk Factors
- HIV accounts for 65% of cases
- Solid organ and hematopoietic stem cell transplantation
- Diabetes
- Alcohol abuse
- Chronic renal failure
- Leukemia, lymphoma, lung cancer
- Sarcoidosis
- Preterm infants
Clinical Manifestations
- Necrotizing pneumonia is usual presentation, as well as nodules, cavitation, pleural effusion, and lung abscess
- Typically subacute onset with fever, cough, and fatigue, as well as pleuritic chest pain
- Specifically in immunocompromised patients, it can cause a cavitary lung disease and is on the differential with mycobacteria and nocardiosis
- Extrapulmonary disease can occur with or without pulmonary involvement
- In conjunction with other infections, can have abscesses in liver, spleen, thyroid, kidney, psoas, bone, prostate, intraabdominal cavity, and paraspinous tissue
- Extrapulmonary disease without pulmonary involvement has three main presentations:
- Localized infection following traumatic inoculation, causing wound infection, traumatic septic arthritis, or endophthalmitis
- Isolated bacteremia with fever, typically recently after chemotherapy causing neutropenia
- Gastrointestional inoculation followed by lymphatic dissemination, causing peritonitis, pelvic masses, and mesenteric adenitis
- Others include otitis media with mastoiditis, colonic polyp infection, and osteomyelitis
Diagnosis
- May be misidentified as Corynebacterium in blood culture or Kocuria on Vitek
Management
- Recommend using at least two agents given increasing rates of resistance
- First-line: combination of macrolide or fluoroquinolone plus rifampin
- First-line: combination of macrolide or fluoroquinolone plus two of: vancomycin, imipenem, linezolid, or an aminoglycoside
- Doses are:
- Azithromycin 500 mg PO/IV once followed by 250 mg PO/IV daily
- Fluoroquinolones: moxifloxacin 400 mg PO daily (preferred), levofloxacin 500 mg PO daily, or ciprofloxacin 750 mg PO BID
- Rifampin 600 mg PO once daily
- Increasing resistance to doxycycline, rifampin, and TMP-SMX
- Treatment usually 6 months or longer