Rhodococcus hoagii: Difference between revisions

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

@@ Line 1: / Line 1: @@
-== Microbiology ==
+==Background==
+===Microbiology===
-* Facultative intracellular, non-spore-forming, [[Has Gram stain::Gram-positive]], weakly acid-fast [[Has shape::coccobacillus]]
+*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
+*Within the family [[Nocardiaceae]] and order [[Actinomycetes]]
+*Obligate aerobic and facultatively intracellular
+*Found in dry and dusty soil
+*Makes red pigment, hence the name
-== Background ==
+===Epidemiology===
+*Infects domesticated animals: [[Horses]] (and in foals it causes pneumonia), [[Goats]], [[Pigs]], [[Sheep]], and [[Cattle]]
-* Found in dry and dusty soil
+*Most commonly infects people with cell-mediated immunodeficiency, particularly [[HIV]], with or without a notable infectious exposure
-* Makes red pigment, hence the name
-* Member of the actinomycetes group
-* Infects domesticated animals
-** Horses
-*** In foals, causes pneumonia
-** Goats
-** Pigs
-** Sheep
-** Cattle
-* Can infect immunocompromised people (HIV, etc)
-== Presentation ==
+===Risk Factors===
+*HIV accounts for 65% of cases
-* Necrotizing pneumonia is usual presentation
+*Solid organ and hematopoietic stem cell transplantation
+*Diabetes
+*Alcohol abuse
+*Chronic renal failure
+*Leukemia, lymphoma, lung cancer
+*Sarcoidosis
+*Preterm infants
+==Clinical Manifestations==
-{{DISPLAYTITLE:''Rhodococcus'' species}}
+*[[Necrotizing pneumonia]] is usual presentation, as well as [[Lung nodules|nodules]], [[Cavitary lung disease|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 [[Mycobacterium species|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
+{{DISPLAYTITLE:''Rhodococcus hoagii''}}
 [[Category:Gram-positive bacteria]]