Brucella

Background

Brucella are gram negative coccobacilli that cause brucellosis.

Brucella species

There are several species of Brucella, including Brucella melitensis, Brucella abortus, Brucella suis, Brucella canis, Brucella ceti, and Brucella pinnipediae. Brucella melitensis is the most pathogenic in humans with its main hosts being goats and sheep. It has been eradicated since the 1970s in the United States but cases still occur, mainly secondary to unpasteurized diary products from outside the United States. Brucella abortus' main host is cattle and cases still occur secondary to wild bison and elk. Brucella Suis' main host is swine and cases result from contact with pigs and hogs. Brucella canis' main host is the dog. Brucella ceti and pinnipediae find hosts in marine species and is cause of neurobrucellosis.

Death from brucellosis occurs in only 2% of cases (CDC).

Transmission

1. Consumption of poorly cooked meat or unpasteurized dairy products (most common mode of transmission).
2. Inhalation of bacteria. Increased in those that work in laboratories that work with the bacteria and slaughterhouse workers.
3. Directly via open skin wounds.
4. Rare modes of transmission include via breastmilk, sexual transmission, tissue transplant, blood transfusion.

Clinical Symptoms

• Fever
• Diaphoresis
• Myalgias
• Headache
• Fatigue

Differential Diagnosis

Lower Respiratory Zoonotic Infections

• Psittacosis
• Anthrax (Bacillus anthracis)
• Brucellosis (Brucella species)
• Q fever (C. burnetti)
• Pasteurellosis (Pasteurella multocida)
• Melioidosis (Burkholderia pseudomallei)
• Rocky Mountain Spotted Fever (R. rickettsii)
• Pulmonic Plague (Yersinia pestis)
• Influenza A
• Hantavirus

Antibiotic Sensitivities

Category	Antibiotic	Sensitivity
Penicillins	Penicillin G	X1
	Penicillin V	X1
Anti-Staphylocccal Penicillins	Methicillin	X1
	Nafcillin/Oxacillin	X1
	Cloxacillin/Diclox.	X1
Amino-Penicillins	AMP/Amox	X1
	Amox-Clav	X1
	AMP-Sulb	X1
Anti-Pseudomonal Penicillins	Ticarcillin	X1
	Ticar-Clav	X1
	Pip-Tazo	X1
	Piperacillin	X1
Carbapenems	Doripenem	X1
	Ertapenem	X1
	Imipenem	X1
	Meropenem	X1
	Aztreonam	X1
Fluroquinolones	Ciprofloxacin	X1
	Ofloxacin	X1
	Pefloxacin	X1
	Levofloxacin	X1
	Moxifloxacin	X1
	Gemifloxacin	X1
	Gatifloxacin	X1
1st G Cephalo	Cefazolin	X1
2nd G. Cephalo	Cefotetan	X1
	Cefoxitin	X1
	Cefuroxime	X1
3rd/4th G. Cephalo	Cefotaxime	X1
	Cefizoxime	X1
	CefTRIAXone	X1
	Ceftaroline	X1
	CefTAZidime	X1
	Cefepime	X1
Oral 1st G. Cephalo	Cefadroxil	X1
	Cephalexin	X1
Oral 2nd G. Cephalo	Cefaclor/Loracarbef	X1
	Cefproxil	X1
	Cefuroxime axetil	X1
Oral 3rd G. Cephalo	Cefixime	X1
	Ceftibuten	X1
	Cefpodox/Cefdinir/Cefditoren	X1
Aminoglycosides	Gentamicin	S+
	Tobramycin	S+
	Amikacin	S+
	Chloramphenicol	S
	Clindamycin	R
Macrolides	Erythromycin	R
	Azithromycin	R
	Clarithromycin	R
Ketolide	Telithromycin	R
Tetracyclines	Doxycycline	S
	Minocycline	S
Glycylcycline	Tigecycline	X1
	Daptomycin	R
Glyco/Lipoclycopeptides	Vancomycin	R
	Teicoplanin	R
	Telavancin	R
	Fusidic Acid	X1
	Trimethoprim	X2
	TMP-SMX	X2
Urinary Agents	Nitrofurantoin	X1
	Fosfomycin	X1
Other	Rifampin	S+
	Metronidazole	R
	Quinupristin dalfoppristin	X1
	Linezolid	R
	Colistimethate	X1

Key

• S susceptible/sensitive (usually)
• I intermediate (variably susceptible/resistant)
• R resistant (or not effective clinically)
• S+ synergistic with cell wall antibiotics
• U sensitive for UTI only (non systemic infection)
• X1 no data
• X2 active in vitro, but not used clinically
• X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
• X4 active in vitro, but not clinically effective for strep pneumonia

See Also

• Microbiology (Main)

References

1. http://www.cdc.gov/brucellosis/
2. WHO Library Cataloguing-in-Publication Data

Brucellosis in humans and animals. Produced by the World Health Organization in collaboration with the Food and Agriculture Organization of the United Nations and World Organisation for Animal Health Principal author: M.J. Corbel. 1.Brucellosis - prevention and control. 2.Brucellosis - epidemiology. 3.Brucellosis - complications. 4.Guidelines. I.Corbel, M.J. II.World Health Organization. III.Food and Agriculture Organization of the United Nations. IV.World Organisation for Animal Health.