Clinical and epidemiologic investigation of two Legionella-Rickettsia co-infections.
BACKGROUND
We treated two patients diagnosed with legionellosis and simultaneous Rickettsia conorii co-infection.


OBJECTIVE
To report the clinical and laboratory characteristics of this unusual combination, and to describe the execution and results of our environmental and epidemiologic investigations.


METHODS
Serial serologic testing was conducted 1, 4 and 7 weeks after initial presentation. Water samples from the patients' residence were cultured for Legionella. Follow-up cultures were taken from identical points at 2 weeks and at 3 months after the initial survey.


RESULTS
Both patients initially expressed a non-specific rise in anti-Legionella immunoglobulin M titers to multiple serotypes. By week 4 a definite pattern of specifically elevated IgG titers became apparent, with patient 1 demonstrating a rise in specific anti-L. pneumophila 12 IgG titer and patient 2 an identical response to L. jordanis. At 4 weeks both patients were positive for both IgM and IgG anti-R. conorii antibodies at a titer > or = 1:100. Heavy growth of Legionella was found in water sampled from the shower heads in the rooms of both patients. Indirect immunofluorescence of water cultures was positive for L. pneumophila 12 and for L. jordanis.


CONCLUSIONS
Although most cases of community-acquired Legionella pneumonia in our region appear simultaneously with at least one other causative agent, co-infection with R. conorii is unusual and has not been reported to date. This report illustrates the importance of cooperation between clinicians and public health practitioners.
Huerta
Michael
M
Soroka Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel. mhuerta@netvision.net.il
Castel
Hana
H
Grotto
Itamar
I
Shpilberg
Ofer
O
Alkan
Michael
M
Harman-Boehm
Ilana
I
D000328:Adult; D000900:Anti-Bacterial Agents; D000907:Antibodies, Bacterial / Q000097:blood; D001907:Boutonneuse Fever / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D004359:Drug Therapy, Combination / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D016952:Legionella pneumophila / Q000276:immunology / Q000302:isolation & purification*; D007877:Legionnaires' Disease / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D008297:Male; D020114:Rickettsia conorii / Q000276:immunology / Q000302:isolation & purification*; D016036:Seroepidemiologic Studies; D012698:Serologic Tests / Q000379:methods; D014871:Water Microbiology
D000900:Anti-Bacterial Agents; D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M