Multidrug-Resistant Gram-Negative Bacteria: Inter- and Intradissemination Among Nursing Homes of Residents With Advanced Dementia.
OBJECTIVE
To quantify the extent of inter- and intra-nursing home transmission of multidrug-resistant gram-negative bacteria (MDRGN) among residents with advanced dementia and characterize MDRGN colonization among these residents.


METHODS
Prospective cohort study.


METHODS
Twenty-two nursing homes in the greater Boston, Massachusetts, area.


METHODS
Residents with advanced dementia.


METHODS
Serial rectal surveillance cultures for MDRGN and resident characteristics were obtained every 3 months for 12 months or until death. Molecular typing of MDRGN isolates was performed by pulsed-field gel electrophoresis.


RESULTS
A total of 190 MDRGN isolates from 152 residents with advanced dementia were included in the analyses. Both intra- and inter-nursing home transmission were identified. Genetically related MDRGN strains, recovered from different residents, were detected in 18 (82%) of the 22 nursing homes. The percent of clonally related strains in these nursing homes ranged from 0% to 86% (average, 35%). More than 50% of strains were clonally related in 3 nursing homes. Co-colonization with more than 1 different MDRGN species occurred among 28 residents (18.4%). A total of 168 (88.4%), 20 (10.5%), and 2 (1.0%) of MDRGN isolates were resistant to 3, 4, and 5 different antimicrobials or antimicrobial classes, respectively.


CONCLUSIONS
MDRGN are spread both within and between nursing homes among residents with advanced dementia. Infection control interventions should begin to target this high-risk group of nursing home residents.
1Division of Infectious Diseases,Rhode Island Hospital,Providence,Rhode Island.
Erika M C
EM
D'Agata
2Hebrew SeniorLife,Department of Medicine,Boston,Massachusetts.
Daniel
D
Habtemariam
2Hebrew SeniorLife,Department of Medicine,Boston,Massachusetts.
Susan
S
Mitchell
D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D003704:Dementia / Q000150:complications; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000235:genetics; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology / Q000635:transmission*; D006801:Humans; D008297:Male; D058889:Molecular Typing; D009735:Nursing Homes; D010802:Phylogeny; D011446:Prospective Studies; D012007:Rectum / Q000382:microbiology
D000900:Anti-Bacterial Agents