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]] |
*Within the family [[Nocardiaceae]] and order [[Actinomycetes]] |
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*Obligate aerobic and facultatively intracellular |
*Obligate aerobic and facultatively intracellular |
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*Most commonly infects people with cell-mediated immunodeficiency, particularly [[HIV]], with or without a notable infectious exposure |
*Most commonly infects people with cell-mediated immunodeficiency, particularly [[HIV]], with or without a notable infectious exposure |
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| − | === |
+ | ===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== |
==Clinical Manifestations== |
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**Gastrointestional inoculation followed by lymphatic dissemination, causing peritonitis, pelvic masses, and mesenteric adenitis |
**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 |
**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== |
==Management== |
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| + | *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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*Treatment usually 6 months or longer |
*Treatment usually 6 months or longer |
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| − | {{DISPLAYTITLE:''Rhodococcus |
+ | {{DISPLAYTITLE:''Rhodococcus hoagii''}} |
[[Category:Gram-positive bacteria]] |
[[Category:Gram-positive bacteria]] |
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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
