Failure to control an outbreak of multidrug-resistant Streptococcus pneumoniae in a long-term-care facility: emergence and ongoing transmission of a fluoroquinolone-resistant strain.
OBJECTIVE
To characterize risk factors associated with pneumococcal disease and asymptomatic colonization during an outbreak of multidrug-resistant Streptococcus pneumoniae (MDRSP) among AIDS patients in a long-term-care facility (LTCF), evaluate the efficacy of antimicrobial prophylaxis in eliminating MDRSP colonization, and describe the emergence of fluoroquinolone resistance in the MDRSP outbreak strain.


METHODS
Epidemiologic investigation based on chart review and characterization of SP strains by antimicrobial susceptibility testing and PFGE and prospective MDRSP surveillance.


METHODS
An 80-bed AIDS-care unit in an LTCF PARTICIPANTS: Staff and residents on the unit.


RESULTS
From April 1995 through January 1996, 7 cases of MDRSP occurred. A nasopharyngeal (NP) swab survey of all residents (n=65) and staff (n=70) detected asymptomatic colonization among 6 residents (9%), but no staff. Isolates were sensitive only to rifampin, ofloxacin, and vancomycin. A 7-day course of rifampin and ofloxacin was given to eliminate colonization among residents: NP swab surveys at 1, 4, and 10 weeks after prophylaxis identified 1 or more colonized residents at each follow-up with isolates showing resistance to one or both treatment drugs. Between 1996 and 1999, an additional 6 patients were diagnosed with fluoroquinolone-resistant (FQ-R) MDRSP infection, with PFGE results demonstrating that the outbreak strain had persisted 3 years after the initial outbreak was recognized.


CONCLUSIONS
Chemoprophylaxis likely contributed to the development of a FQ-R outbreak strain that continued to be transmitted in the facility through 1999. Long-term control of future MDRSP outbreaks should rely primarily on vaccination and strict infection control measures.
Carter
Rosalind J
RJ
Bureau of Communicable Disease, New York City Department of Health and Mental Hygiene, New York, New York 10013, USA.
Sorenson
Genevieve
G
Heffernan
Richard
R
Kiehlbauch
Julia A
JA
Kornblum
John S
JS
Leggiadro
Robert J
RJ
Nixon
Lucia J
LJ
Wertheim
William A
WA
Whitney
Cynthia G
CG
Layton
Marcelle
M
D000163:Acquired Immunodeficiency Syndrome / Q000150:complications / Q000382:microbiology; D000328:Adult; D019072:Antibiotic Prophylaxis; D001428:Bacterial Vaccines / Q000276:immunology; D003428:Cross Infection / Q000382:microbiology* / Q000517:prevention & control / Q000635:transmission; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004196:Disease Outbreaks / Q000517:prevention & control*; D024881:Drug Resistance, Bacterial / Q000187:drug effects / Q000276:immunology; D018432:Drug Resistance, Multiple / Q000187:drug effects / Q000276:immunology; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006268:Health Facilities; D006801:Humans; D007902:Length of Stay; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D009302:Nasopharyngeal Diseases / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control; D009518:New York / Q000453:epidemiology; D011008:Pneumococcal Infections / Q000150:complications / Q000453:epidemiology / Q000382:microbiology*; D012307:Risk Factors; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*
D001428:Bacterial Vaccines; D004269:DNA, Bacterial