Listeria monocytogenes: Difference between revisions
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Listeria monocytogenes
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| − | == |
+ | ==Background== |
| − | === |
+ | ===Microbiology=== |
| − | * Facultatively anaerobic, intracellular, non-sporulating, catalase-positive]], oxidase-negative]], short, non [[Catalase::branching, [[Stain::Gram [[Oxidase::positive]] [[Cellular shape::bacillus]] that grows readily on blood agar, producing incomplete β-hemolysis |
||
| − | ** Can be [[Stain::Gram-variable]] and [[Cellular shape::pleiomorphic]] |
||
| − | ** Can be initially misidentified as a diphtheroid |
||
| − | * 1 to 6 polar flagellae with '''tumbling motility''' at 25ºC |
||
| − | ** Demonstrates "umbrella" motility in the tube |
||
| − | * Can grow at refrigerator temperatures, as low as 4ºC |
||
| − | * Doesn't grow on usual stool culture plates |
||
| − | * 13 serovars based on cellular O and flagellar H antigens |
||
| − | ** Most disease from 4b, 1/2a, and 1/2b |
||
| + | *Facultatively anaerobic, intracellular, non-sporulating, catalase [[Catalase::positive]], oxidase [[Oxidase::negative]], short, non-branching, [[Stain::Gram-positive]] [[Shape::bacillus]] that grows readily on blood agar, producing incomplete β-hemolysis |
||
| − | === Epidemiology === |
||
| + | **Can be [[Stain::Gram-variable]] and [[Shape::pleomorphic]] |
||
| − | * In newborns, transmitted vertically from the mother |
||
| + | **Can be initially misidentified as a diphtheroid |
||
| − | * In others, it is acquired from ingestion of contaminated food followed by mucosal invasion and bacteremia |
||
| + | *1 to 6 polar flagellae with '''tumbling motility''' at 25ºC |
||
| − | * The bacterium can grow at fridge temperatures |
||
| + | **Demonstrates "umbrella" motility in the tube |
||
| − | * Both sporadic cases as well as foodborne outbreaks |
||
| + | *Can grow at refrigerator temperatures, as low as 4ºC |
||
| − | ** Largest outbreak in Canada was associated with deli meats in 2008 |
||
| + | *Doesn't grow on usual stool culture plates |
||
| − | ** Other outbreaks include ice cream (2015), frozen foods (2016), deli meat at a Druxy's in Princess Margaret Hospital (2018), prepackaged salads and kale (2018) |
||
| + | *13 serovars based on cellular O and flagellar H antigens |
||
| − | ** Refer to the [http://www.inspection.gc.ca/about-the-cfia/newsroom/food-recall-warnings/eng/1299076382077/1299076493846 Canada Food Inspection Agency] for current recalls |
||
| + | **Most disease from 4b, 1/2a, and 1/2b |
||
| − | === |
+ | ===Epidemiology=== |
| − | * In gut, it is phagocytosed into endothelial cells, then disseminates hematogenously |
||
| − | ** Endocytosis is aided by LPXTG on the mucosal cell surface and helps it to adhere, as well as E-cadherin, which activates phagocytosis |
||
| − | *** Some hypothesize that uptake of Listeria is increased by concurrent GI infections |
||
| − | ** Listeriolysin O, the major virulence factor, is a pore-forming toxin that prevents T-cell response |
||
| − | ** Listeriolysin O and phspholipases help is escape the phagosome |
||
| − | ** Once in the cytoplasm, they activate actin to carry them to the cell membrane, where they push out and form filopods which can be phagocytosed by nearby cells |
||
| − | ** Moves from cell to cell without time spent outside |
||
| − | * In the CNS, it can invade the blood-brain barrier endothelial cells directly, or it can be transported across by cirtculating white blood cells ("Trojan horse" mechanism), or it can be inoculated into oral tissues followed by macrophage phagocytosis and invasion of cranial nerves |
||
| − | ** The latter may be most important for rhomboencephalitis |
||
| − | * Immune response primarily cell-mediated rather than antibody-mediated, since the bacterium doesn't spend any time outside of cells |
||
| + | *In newborns, transmitted vertically from the mother |
||
| − | === Risk Factors === |
||
| + | *In others, it is acquired from ingestion of contaminated food followed by mucosal invasion and bacteremia |
||
| − | * Mostly around impaired cellular immunity |
||
| + | *The bacterium can grow at fridge temperatures |
||
| − | * Lymphoma, pregnancy, AIDS, and corticosteroid immunosuppression, especially in transplant recipients |
||
| + | *Both sporadic cases as well as foodborne outbreaks |
||
| − | * In AIDS and transplantation, may be prevented by ''Pneumocystis'' prophylaxis |
||
| + | **Largest outbreak in Canada was associated with deli meats in 2008 |
||
| − | * Use of anti-TNF-alpha medications |
||
| + | **Other outbreaks include ice cream (2015), frozen foods (2016), deli meat at a Druxy's in Princess Margaret Hospital (2018), prepackaged salads and kale (2018) |
||
| − | * Antacids that lower stomach acidity |
||
| + | **Refer to the [http://www.inspection.gc.ca/about-the-cfia/newsroom/food-recall-warnings/eng/1299076382077/1299076493846 Canada Food Inspection Agency] for current recalls |
||
| + | ===Pathophysiology=== |
||
| − | == Clinical Manifestations == |
||
| + | *In gut, it is phagocytosed into endothelial cells, then disseminates hematogenously |
||
| − | * Incubation period for invasive disease is [[Usual incubation period::30 days]] (range [[Incubation period range::11 to 90 days]]) |
||
| + | **Endocytosis is aided by LPXTG on the mucosal cell surface and helps it to adhere, as well as E-cadherin, which activates phagocytosis |
||
| + | ***Some hypothesize that uptake of Listeria is increased by concurrent GI infections |
||
| + | **Listeriolysin O, the major virulence factor, is a pore-forming toxin that prevents T-cell response |
||
| + | **Listeriolysin O and phspholipases help is escape the phagosome |
||
| + | **Once in the cytoplasm, they activate actin to carry them to the cell membrane, where they push out and form filopods which can be phagocytosed by nearby cells |
||
| + | **Moves from cell to cell without time spent outside |
||
| + | *In the CNS, it can invade the blood-brain barrier endothelial cells directly, or it can be transported across by cirtculating white blood cells ("Trojan horse" mechanism), or it can be inoculated into oral tissues followed by macrophage phagocytosis and invasion of cranial nerves |
||
| + | **The latter may be most important for rhomboencephalitis |
||
| + | *Immune response primarily cell-mediated rather than antibody-mediated, since the bacterium doesn't spend any time outside of cells |
||
| − | === |
+ | ===Risk Factors=== |
| − | * Most common presentation outside of neonatal period is as a non-specific febrile illness |
||
| − | * Can cause non-specific febrile illness, often with a prodrome of diarrhea and nausea, myalgias |
||
| + | *Mostly around impaired cellular immunity |
||
| − | === Febrile gastroenteritis === |
||
| + | *[[Lymphoma]], [[pregnancy]] (especially third trimester), advanced [[HIV]], and [[Corticosteroids|corticosteroid]] immunosuppression, especially in transplant recipients |
||
| − | * Diarrhea, nausea, and vomiting, often with fever |
||
| + | *In HIV and transplantation, may be prevented by ''[[Pneumocystis jirovecii|Pneumocystis]]'' prophylaxis |
||
| − | * Associated with foodborne outbreaks, including chocolate milk, cold corn and tuna salad, cold smoked trout, deli meat |
||
| + | *Use of [[TNF-α inhibitors|anti-TNF-α medications]] |
||
| − | * Non-invasive in healthy patients |
||
| + | *Antacids that lower stomach acidity |
||
| − | * Needs high innoculum |
||
| + | ==Clinical Manifestations== |
||
| − | === CNS infection === |
||
| − | * Causes a spectrum of CNS disease from meningitis to encephalitis to rhombencephalitis to abscesses |
||
| + | *Incubation period for invasive disease is [[Usual incubation period::30 days]] (range [[Incubation period range::11 to 90 days]]) |
||
| − | ==== Meningitis ==== |
||
| − | * A bacterial meningitis with high mortality, usually in very young, old >50 years, pregnant, or immunocompromised |
||
| − | ** Malignancy is the most common risk factor, followed by transplantation, alcohol use disorder, immunosuppression, diabetes, and HIV |
||
| − | * Symptoms include subacute presention of fevers, nausea, and headache, with meningismus, and altered and fluctuating mental status |
||
| − | * Focal neurologic deficits |
||
| − | * Can sometimes have movement disorders, including ataxia, termors, and myoclonus, as well as seizures |
||
| − | * Two thirds have neutrophil-predominant CSF |
||
| − | * Mortality 15-30% |
||
| − | * Even if cured, can be left with permanent focal neurologic deficits |
||
| + | ===Bacteremia=== |
||
| − | ==== Encephalitis/Cerebritis ==== |
||
| − | * Localized parenchymal infection that can lead to abscess formation |
||
| − | * Altered consciousness and cognitive dysfunction |
||
| − | * CSF cultures only positive about half the time |
||
| − | * Can mimic herpes encephalitis |
||
| + | *Most common presentation outside of neonatal period is as a non-specific febrile illness |
||
| − | ==== Rhombencephalitis ==== |
||
| + | *Can cause non-specific febrile illness, often with a prodrome of diarrhea and nausea, myalgias |
||
| − | * Brainstem encephalitis |
||
| − | * Can occur in health adults |
||
| − | * Diphasic illness, with prodrome of fever, headache, nausea, and vomiting lasting 4 days, followed by asymmetric cranial nerve deficits, cerebellar dysfunction, and focal neurological deficits |
||
| − | * Half of patients have respiratory failure |
||
| − | * CSF often only mildly abnormal |
||
| − | === |
+ | ===Febrile Gastroenteritis=== |
| − | * Often bacteremic and concurrent meningitis |
||
| − | * Can have abscesses in unusual locations, including subcortical abscesses of the thalamus, pons, and medulla |
||
| + | *Diarrhea, nausea, and vomiting, often with fever |
||
| − | === Spinal cord infection === |
||
| + | *Associated with foodborne outbreaks, including chocolate milk, cold corn and tuna salad, cold smoked trout, deli meat |
||
| − | * Rare cases |
||
| + | *Non-invasive in healthy patients |
||
| + | *Needs high innoculum |
||
| − | === |
+ | ===CNS Infections=== |
| − | * Can affect both native and prosthetic valves |
||
| − | * Mortality 50% |
||
| + | *Causes a spectrum of CNS disease from meningitis to encephalitis to rhombencephalitis to abscesses |
||
| − | === Neonatal listeriosis === |
||
| − | * Stillbirth or spontaneous abortion is common, related to disseminated listeriosis called granulomatosis infantiseptica |
||
| − | ** Widespread abscesses and granulomas, especially in liver and spleen |
||
| − | ** ''Listeria'' can be isolated from meconium |
||
| − | * Can also present in prematurity as early-onset sepsis, probably acquired in utero |
||
| − | ** ''Listeria'' can be isolated from conjunctiva, ear, nose, throat, meconium, amniotic fluid, placenta, blood, and sometimes CSF |
||
| − | * Can also present in term births as late-onset meningitis (~2 weeks post-partum) |
||
| − | ** Probably acquired during delivery, since it is far less common with cesarean section |
||
| + | ====Meningitis==== |
||
| − | === Other sites of infection === |
||
| − | * Conjunctivitis, skin infection, and lymphadenitis |
||
| − | * Hepatitis, liver abscesses, cholecystitis, perintonitis, splenic abscesses, pleural and pulmonary infections, septic arthritis, osteomyelitis, necrotizing fasciitis, pericarditis, myocarditits, arteritis, and endophthalmitis |
||
| + | *A bacterial meningitis with high mortality, usually in very young, old >50 years, pregnant, or immunocompromised |
||
| − | == Diagnosis == |
||
| + | **Malignancy is the most common risk factor, followed by transplantation, alcohol use disorder, immunosuppression, diabetes, and HIV |
||
| − | * Can be directly seen in blood or CSF, and cultured |
||
| + | *Symptoms include subacute presention of fevers, nausea, and headache, with meningismus, and altered and fluctuating mental status |
||
| − | ** Grows on blood agar with incomplete beta-hemolysis |
||
| + | *Focal neurologic deficits |
||
| − | ** Can also do cold-enrichment, incubating the plates at 4 to 10 ºC |
||
| + | *Can sometimes have movement disorders, including ataxia, termors, and myoclonus, as well as seizures |
||
| − | ** Growth may be inhibited by usual stool culture plates |
||
| + | *Two thirds have neutrophil-predominant CSF |
||
| − | * Serology to listeriolysin O can be helpful in non-invasive disease |
||
| + | *Mortality 15-30% |
||
| − | * PCR is possible for CSF and tissue, detecting the ''hly'' gene that encodes listeriolysin O |
||
| + | *Even if cured, can be left with permanent focal neurologic deficits |
||
| − | * MRI can diagnose abscess (vs meningitis) |
||
| + | ====Encephalitis/Cerebritis==== |
||
| − | == Management == |
||
| − | * Good supportive care |
||
| − | * It has intrinsic resistance to cephalosporins |
||
| − | * [[Ampicillin]] 2 g IV q4h is standard |
||
| − | ** Delayed bactericidal activity |
||
| − | * [[TMP-SMX]] 5/25 mg/kg IV q8h is second-line |
||
| − | * If severe, can combine [[ampicillin]] and [[TMP-SMX]] |
||
| − | ** Lower failure rate with fewer neurological sequelae than amp/gent |
||
| − | * [[Vancomycin]] and [[meropenem]] can be considered third-line |
||
| − | * [[Daptomycin]] and [[linezolid]] have in vitro activity |
||
| − | * Duration |
||
| − | ** Bacteremia: 2 weeks |
||
| − | ** CNS involvement: 3 weeks |
||
| − | ** Rhomboencephalitis or abscess: at least 6 weeks with serial imaging |
||
| − | ** Endocarditis: 4 to 6 weeks |
||
| + | *Localized parenchymal infection that can lead to abscess formation |
||
| − | == Prevention == |
||
| + | *Altered consciousness and cognitive dysfunction |
||
| − | * Follow good food preparation practices |
||
| + | *CSF cultures only positive about half the time |
||
| + | *Can mimic herpes encephalitis |
||
| + | ====Rhombencephalitis==== |
||
| − | === General Recommendations === |
||
| − | ==== Washing and Handling Food ==== |
||
| − | * Rinse raw produce under tap-water, including produce you later peel |
||
| − | * Scrub firm produce with a clean brush |
||
| − | * Dry it with a clean cloth |
||
| + | *Brainstem encephalitis |
||
| − | ==== Clean and Safe Kitchen ==== |
||
| + | *Can occur in health adults |
||
| − | * Wash everything |
||
| + | *Diphasic illness, with prodrome of fever, headache, nausea, and vomiting lasting 4 days, followed by asymmetric cranial nerve deficits, cerebellar dysfunction, and focal neurological deficits |
||
| − | * Make sure your freezer freezes |
||
| + | *Half of patients have respiratory failure |
||
| − | * Clean fridge spills quickly |
||
| + | *CSF often only mildly abnormal |
||
| − | ==== |
+ | ====Brain Abscess==== |
| − | * Cook it to safe internal temperature |
||
| − | * Use pre-packaged stuff as quickly as possible |
||
| − | * Use leftovers within 3 to 4 days |
||
| + | *Often bacteremic and concurrent meningitis |
||
| − | === Safer Foods === |
||
| + | *Can have abscesses in unusual locations, including subcortical abscesses of the thalamus, pons, and medulla |
||
| − | * No unpasteurized milk or milk products |
||
| + | ===Spinal Cord Infection=== |
||
| − | === Higher-risk Persons === |
||
| − | ==== Meats ==== |
||
| − | * No hot dogs, deli meats, fermented or dry sausages, unless they are cooked to 165ºF before serving |
||
| − | * Avoid getting hot dog juice or other meat juice on things |
||
| − | * Don't eat pate or meat spreads that aren't canned, and refridgerate after opening |
||
| + | *Rare cases |
||
| − | ==== Cheeses ==== |
||
| − | * Only eat soft cheeses if they are made with pasteurized milk |
||
| − | === |
+ | ===Endocarditis=== |
| − | * No refrigerated smoked seafood unless it is cooked or canned |
||
| − | * Canned seafood is safe |
||
| + | *Can affect both native and prosthetic valves |
||
| − | ==== Melons ==== |
||
| + | *Mortality 50% |
||
| − | * Wash hands after handling the melon |
||
| + | |||
| − | * Scrub the melon clean and drug it well, sanitizing the brush between uses |
||
| + | ===Neonatal Listeriosis=== |
||
| − | * Don't keep cut pieces for longer than 7 days |
||
| + | |||
| − | * Don't leave out for longer than 4 hours |
||
| + | *Infection in first and second trimester frequently result in intrauterine fetal death |
||
| + | *Later in pregnancy, stillbirth or spontaneous abortion is common |
||
| + | *Presents in prematurity or neonatal period as early-onset sepsis, likely acquired in utero during third trimester |
||
| + | **Disseminated listeriosis called '''granulomatosis infantiseptica''' |
||
| + | **Widespread abscesses and granulomas, especially in lungs, liver, and spleen |
||
| + | **Can have a miliary pattern on chest x-ray |
||
| + | **''Listeria'' can be isolated from conjunctiva, ear, nose, throat, meconium, amniotic fluid, placenta, blood, and sometimes CSF |
||
| + | *Can also present in term births as late-onset meningitis (~2 weeks post-partum) |
||
| + | **Probably acquired during delivery, since it is far less common with cesarean section |
||
| + | *Mortality in neonatal infections is high at around 45% |
||
| + | |||
| + | ===Other Sites of Infection=== |
||
| + | |||
| + | *Conjunctivitis, skin infection, and lymphadenitis |
||
| + | *Hepatitis, liver abscesses, cholecystitis, perintonitis, splenic abscesses, pleural and pulmonary infections, septic arthritis, osteomyelitis, necrotizing fasciitis, pericarditis, myocarditits, arteritis, and endophthalmitis |
||
| + | |||
| + | ==Diagnosis== |
||
| + | |||
| + | *Can be directly seen in blood or CSF, and cultured |
||
| + | **Grows on blood agar with incomplete beta-hemolysis |
||
| + | **Can also do cold-enrichment, incubating the plates at 4 to 10 ºC |
||
| + | **Growth may be inhibited by usual stool culture plates |
||
| + | *Serology to listeriolysin O can be helpful in non-invasive disease |
||
| + | *PCR is possible for CSF and tissue, detecting the ''hly'' gene that encodes listeriolysin O |
||
| + | *MRI can diagnose abscess (vs meningitis) |
||
| + | |||
| + | ==Management== |
||
| + | |||
| + | *Good supportive care |
||
| + | *It has intrinsic resistance to cephalosporins |
||
| + | *[[Ampicillin]] 2 g IV q4h is standard |
||
| + | **Delayed bactericidal activity |
||
| + | *[[TMP-SMX]] 5/25 mg/kg IV q8h is second-line |
||
| + | *If severe, can combine [[ampicillin]] and [[TMP-SMX]] |
||
| + | **Lower failure rate with fewer neurological sequelae than amp/gent |
||
| + | *[[Vancomycin]] and [[meropenem]] can be considered third-line |
||
| + | *[[Daptomycin]] and [[linezolid]] have in vitro activity |
||
| + | *Duration |
||
| + | **Bacteremia: 2 weeks |
||
| + | **CNS involvement: 3 weeks |
||
| + | **Rhomboencephalitis or abscess: at least 6 weeks with serial imaging |
||
| + | **Endocarditis: 4 to 6 weeks |
||
| + | |||
| + | ==Prevention== |
||
| + | |||
| + | *Follow good food preparation practices |
||
| + | |||
| + | ===General Recommendations=== |
||
| + | ====Washing and Handling Food==== |
||
| + | |||
| + | *Rinse raw produce under tap-water, including produce you later peel |
||
| + | *Scrub firm produce with a clean brush |
||
| + | *Dry it with a clean cloth |
||
| + | |||
| + | ====Clean and Safe Kitchen==== |
||
| + | |||
| + | *Wash everything |
||
| + | *Make sure your freezer freezes |
||
| + | *Clean fridge spills quickly |
||
| + | |||
| + | ====Cook Meat Well==== |
||
| + | |||
| + | *Cook it to safe internal temperature |
||
| + | *Use pre-packaged stuff as quickly as possible |
||
| + | *Use leftovers within 3 to 4 days |
||
| + | |||
| + | ===Safer Foods=== |
||
| + | |||
| + | *No unpasteurized milk or milk products |
||
| + | |||
| + | ===Higher-risk Persons=== |
||
| + | ====Meats==== |
||
| + | |||
| + | *No hot dogs, deli meats, fermented or dry sausages, unless they are cooked to 165ºF before serving |
||
| + | *Avoid getting hot dog juice or other meat juice on things |
||
| + | *Don't eat pate or meat spreads that aren't canned, and refridgerate after opening |
||
| + | |||
| + | ====Cheeses==== |
||
| + | |||
| + | *Only eat soft cheeses if they are made with pasteurized milk |
||
| + | |||
| + | ====Seafood==== |
||
| + | |||
| + | *No refrigerated smoked seafood unless it is cooked or canned |
||
| + | *Canned seafood is safe |
||
| + | |||
| + | ====Melons==== |
||
| + | |||
| + | *Wash hands after handling the melon |
||
| + | *Scrub the melon clean and drug it well, sanitizing the brush between uses |
||
| + | *Don't keep cut pieces for longer than 7 days |
||
| + | *Don't leave out for longer than 4 hours |
||
{{DISPLAYTITLE:''Listeria monocytogenes''}} |
{{DISPLAYTITLE:''Listeria monocytogenes''}} |
||
Latest revision as of 09:51, 26 November 2020
Background
Microbiology
- Facultatively anaerobic, intracellular, non-sporulating, catalase positive, oxidase negative, short, non-branching, Gram-positive bacillus that grows readily on blood agar, producing incomplete β-hemolysis
- Can be Gram-variable and pleomorphic
- Can be initially misidentified as a diphtheroid
- 1 to 6 polar flagellae with tumbling motility at 25ºC
- Demonstrates "umbrella" motility in the tube
- Can grow at refrigerator temperatures, as low as 4ºC
- Doesn't grow on usual stool culture plates
- 13 serovars based on cellular O and flagellar H antigens
- Most disease from 4b, 1/2a, and 1/2b
Epidemiology
- In newborns, transmitted vertically from the mother
- In others, it is acquired from ingestion of contaminated food followed by mucosal invasion and bacteremia
- The bacterium can grow at fridge temperatures
- Both sporadic cases as well as foodborne outbreaks
- Largest outbreak in Canada was associated with deli meats in 2008
- Other outbreaks include ice cream (2015), frozen foods (2016), deli meat at a Druxy's in Princess Margaret Hospital (2018), prepackaged salads and kale (2018)
- Refer to the Canada Food Inspection Agency for current recalls
Pathophysiology
- In gut, it is phagocytosed into endothelial cells, then disseminates hematogenously
- Endocytosis is aided by LPXTG on the mucosal cell surface and helps it to adhere, as well as E-cadherin, which activates phagocytosis
- Some hypothesize that uptake of Listeria is increased by concurrent GI infections
- Listeriolysin O, the major virulence factor, is a pore-forming toxin that prevents T-cell response
- Listeriolysin O and phspholipases help is escape the phagosome
- Once in the cytoplasm, they activate actin to carry them to the cell membrane, where they push out and form filopods which can be phagocytosed by nearby cells
- Moves from cell to cell without time spent outside
- Endocytosis is aided by LPXTG on the mucosal cell surface and helps it to adhere, as well as E-cadherin, which activates phagocytosis
- In the CNS, it can invade the blood-brain barrier endothelial cells directly, or it can be transported across by cirtculating white blood cells ("Trojan horse" mechanism), or it can be inoculated into oral tissues followed by macrophage phagocytosis and invasion of cranial nerves
- The latter may be most important for rhomboencephalitis
- Immune response primarily cell-mediated rather than antibody-mediated, since the bacterium doesn't spend any time outside of cells
Risk Factors
- Mostly around impaired cellular immunity
- Lymphoma, pregnancy (especially third trimester), advanced HIV, and corticosteroid immunosuppression, especially in transplant recipients
- In HIV and transplantation, may be prevented by Pneumocystis prophylaxis
- Use of anti-TNF-α medications
- Antacids that lower stomach acidity
Clinical Manifestations
- Incubation period for invasive disease is 30 days (range 11 to 90 days)
Bacteremia
- Most common presentation outside of neonatal period is as a non-specific febrile illness
- Can cause non-specific febrile illness, often with a prodrome of diarrhea and nausea, myalgias
Febrile Gastroenteritis
- Diarrhea, nausea, and vomiting, often with fever
- Associated with foodborne outbreaks, including chocolate milk, cold corn and tuna salad, cold smoked trout, deli meat
- Non-invasive in healthy patients
- Needs high innoculum
CNS Infections
- Causes a spectrum of CNS disease from meningitis to encephalitis to rhombencephalitis to abscesses
Meningitis
- A bacterial meningitis with high mortality, usually in very young, old >50 years, pregnant, or immunocompromised
- Malignancy is the most common risk factor, followed by transplantation, alcohol use disorder, immunosuppression, diabetes, and HIV
- Symptoms include subacute presention of fevers, nausea, and headache, with meningismus, and altered and fluctuating mental status
- Focal neurologic deficits
- Can sometimes have movement disorders, including ataxia, termors, and myoclonus, as well as seizures
- Two thirds have neutrophil-predominant CSF
- Mortality 15-30%
- Even if cured, can be left with permanent focal neurologic deficits
Encephalitis/Cerebritis
- Localized parenchymal infection that can lead to abscess formation
- Altered consciousness and cognitive dysfunction
- CSF cultures only positive about half the time
- Can mimic herpes encephalitis
Rhombencephalitis
- Brainstem encephalitis
- Can occur in health adults
- Diphasic illness, with prodrome of fever, headache, nausea, and vomiting lasting 4 days, followed by asymmetric cranial nerve deficits, cerebellar dysfunction, and focal neurological deficits
- Half of patients have respiratory failure
- CSF often only mildly abnormal
Brain Abscess
- Often bacteremic and concurrent meningitis
- Can have abscesses in unusual locations, including subcortical abscesses of the thalamus, pons, and medulla
Spinal Cord Infection
- Rare cases
Endocarditis
- Can affect both native and prosthetic valves
- Mortality 50%
Neonatal Listeriosis
- Infection in first and second trimester frequently result in intrauterine fetal death
- Later in pregnancy, stillbirth or spontaneous abortion is common
- Presents in prematurity or neonatal period as early-onset sepsis, likely acquired in utero during third trimester
- Disseminated listeriosis called granulomatosis infantiseptica
- Widespread abscesses and granulomas, especially in lungs, liver, and spleen
- Can have a miliary pattern on chest x-ray
- Listeria can be isolated from conjunctiva, ear, nose, throat, meconium, amniotic fluid, placenta, blood, and sometimes CSF
- Can also present in term births as late-onset meningitis (~2 weeks post-partum)
- Probably acquired during delivery, since it is far less common with cesarean section
- Mortality in neonatal infections is high at around 45%
Other Sites of Infection
- Conjunctivitis, skin infection, and lymphadenitis
- Hepatitis, liver abscesses, cholecystitis, perintonitis, splenic abscesses, pleural and pulmonary infections, septic arthritis, osteomyelitis, necrotizing fasciitis, pericarditis, myocarditits, arteritis, and endophthalmitis
Diagnosis
- Can be directly seen in blood or CSF, and cultured
- Grows on blood agar with incomplete beta-hemolysis
- Can also do cold-enrichment, incubating the plates at 4 to 10 ºC
- Growth may be inhibited by usual stool culture plates
- Serology to listeriolysin O can be helpful in non-invasive disease
- PCR is possible for CSF and tissue, detecting the hly gene that encodes listeriolysin O
- MRI can diagnose abscess (vs meningitis)
Management
- Good supportive care
- It has intrinsic resistance to cephalosporins
- Ampicillin 2 g IV q4h is standard
- Delayed bactericidal activity
- TMP-SMX 5/25 mg/kg IV q8h is second-line
- If severe, can combine ampicillin and TMP-SMX
- Lower failure rate with fewer neurological sequelae than amp/gent
- Vancomycin and meropenem can be considered third-line
- Daptomycin and linezolid have in vitro activity
- Duration
- Bacteremia: 2 weeks
- CNS involvement: 3 weeks
- Rhomboencephalitis or abscess: at least 6 weeks with serial imaging
- Endocarditis: 4 to 6 weeks
Prevention
- Follow good food preparation practices
General Recommendations
Washing and Handling Food
- Rinse raw produce under tap-water, including produce you later peel
- Scrub firm produce with a clean brush
- Dry it with a clean cloth
Clean and Safe Kitchen
- Wash everything
- Make sure your freezer freezes
- Clean fridge spills quickly
Cook Meat Well
- Cook it to safe internal temperature
- Use pre-packaged stuff as quickly as possible
- Use leftovers within 3 to 4 days
Safer Foods
- No unpasteurized milk or milk products
Higher-risk Persons
Meats
- No hot dogs, deli meats, fermented or dry sausages, unless they are cooked to 165ºF before serving
- Avoid getting hot dog juice or other meat juice on things
- Don't eat pate or meat spreads that aren't canned, and refridgerate after opening
Cheeses
- Only eat soft cheeses if they are made with pasteurized milk
Seafood
- No refrigerated smoked seafood unless it is cooked or canned
- Canned seafood is safe
Melons
- Wash hands after handling the melon
- Scrub the melon clean and drug it well, sanitizing the brush between uses
- Don't keep cut pieces for longer than 7 days
- Don't leave out for longer than 4 hours
