In point-prevalence surveys , prevalences of antibiotic-resistant gram-negative bacteria in perianal swabs were significantly lower during SDD compared with SOD ; for aminoglycoside resistance , average prevalence was 5.6 % ( 95 % CI , 4.6 % -6.7 % ) during SDD and 11.8 % ( 95 % CI , 10.3 % -13.2 % ) during SOD ( P < .001 ) .