Table 1.Clinical Settings in Which Listeriosis Should Be Considered Strongly in the Differential Diagnosis　 

Neonatal sepsis or meningitis

Meningitis or parenchymal brain infection in patients with hematological malignancies, AIDS, organ transplantation, or corticosteroid immunosuppression

Meningitis or parenchymal brain infection in adults older than 50 years

Simultaneous infection of the meninges and brain parenchyma

Subcortical brain abscess

Fever during pregnancy, particularly in the third trimester

Blood, CSF, or other normally sterile specimen reported to have "diphtheroids" on Gram stain or culture

Foodborne outbreak of febrile gastroenteritis when routine cultures fail to identify a pathogen

 

Table 2.  Antimicrobial Susceptibilities of Listeria monocytogenes*

	MIC (ug/ml)
Drug	Range	50%	90%
Ampicillin	0.03-1	0.5	0.5
Penicillin	0.06-2	0.5	1
Oxacillin	0.5-4	1	2
Piperacillin	0.5-2	1	2
Clindamycin	0.25-4	1	2
Chloramphenicol	2-8	4	8
Erythromycin	0.1-1	0.5	1
Clarithromycin	0.06-0.5	0.5	0.5
Rifampin	0.008-0.25	0.06	0.25
Tetracycline	0.5-4	1	2
Sulfamethoxazole	16-32	16	32
Trimethoprim	0.03-0.12	0.06	0.12
Trimethoprim-sulfamethoxazole	0.012-0.5	0.5	0.5
Gentamicin	0.25-2	0.5	1
Cefazolin	1-4	2	4
Ceftriaxone	4->128	128	>128
Ceftazidime	128->128	128	>128
Cefipime	4-64	64	64
Imipenem	0.5-4	2	4
Vancomycin	0.5-2	1	1
Ciprofloxacin	0.5-2	1	2
Levofloxacin	0.25-2	0.5	1

* Data are adapted from references 1, 8, 16, 22, 23, 29, 33, 40-42, 44, 45,

 

Table 3.   Intravenous Therapy of Invasive Listerial Infection  [Download PDF]

SYNDROME	ANTIBIOTIC*	DOSAGE**	INTERVAL	MINIMUM
Meningitis	Ampicillin	200 mg/kg	q4h	3wk
	plus Gentamicin	5 mg/kg	q24h
Brain abscess or rhombencephalitis	Ampicillin	200 mg/kg	q4h	6wk
	plus Gentamicin	5 mg/kg	q24h
Endocarditis	Ampicillin	200 mg/kg	q4h	6wk
	plus Gentamicin	5 mg/kg	q24h
Bacteremia	Ampicillin	200 mg/kg	q4h	2wk

 

*  Penicillin allergic patients without endocarditis can be treated with trimethoprim-sulfamethoxazole alone, using 15mg/kg of trimethoprim daily at 6-8 hour intervals.  Patients with endocarditis should be desensitized to ampicillin and treated as above.

** Maximum daily dose of ampicillin should not exceed 15 grams