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Although transmission of human norovirus in food establishments is commonly attributed to consumption of contaminated food, transmission via contaminated environmental surfaces, such as those in bathrooms, may also play a role. Our aim was to determine the prevalence of human norovirus on bathroom surfaces in commercial food establishments in New Jersey, Ohio, and South Carolina under nonoutbreak conditions and to determine characteristics associated with the presence of human norovirus. Food establishments (751) were randomly selected from nine counties in each state. Four surfaces (underside of toilet seat, flush handle of toilet, inner door handle of stall or outer door, and sink faucet handle) were swabbed in male and female bathrooms using premoistened macrofoam swabs. A checklist was used to collect information about the characteristics, materials, and mechanisms of objects in bathrooms. In total, 61 (1.5%) of 4,163 swabs tested were presumptively positive for human norovirus, 9 of which were confirmed by sequencing. Some factors associated with the presence of human norovirus included being from South Carolina (odd ratio [OR], 2.4; 95% confidence interval [CI], 1.2 to 4.9; P < 0.05) or New Jersey (OR, 1.7; 95% CI, 0.9 to 3.3; 0.05 < P < 0.10), being a chain establishment (OR, 1.9; 95% CI, 1.1 to 3.3; P < 0.05), being a unisex bathroom (versus male: OR, 2.0; 95% CI, 0.9 to 4.1; 0.05 < P < 0.10; versus female: OR, 2.6; 95% CI, 1.2 to 5.7; P < 0.05), having a touchless outer door handle (OR, 3.3; 95% CI, 0.79 to 13.63; 0.05 < P < 0.10), and having an automatic flush toilet (OR, 2.5, 95% CI, 1.1 to 5.3; 0.05 < P < 0.10). Our findings confirm that the presence of human norovirus on bathroom surfaces in commercial food establishments under nonoutbreak conditions is a rare event. Therefore, routine environmental monitoring for human norovirus contamination during nonoutbreak periods is not an efficient method of monitoring norovirus infection risk.

The compost microcosm is a prime site for bacterial interaction that carries the inherent potential for disseminating antibiotic resistance through genetic exchange and subsequent land application. One hundred and thirty-six Escherichia coli isolates from compost heaps in South Carolina and California from a total of 277 compost samples were classified to phylogenetic groups, tested for resistance to 10 antibiotics, and screened for shiga toxins and integrons. Isolates that had identical antibiotic resistance patterns, grouped phylogenetically, and came from the same sample source were tested with pulsed-field gel electrophoresis. All isolates were negative for shiga toxins 1 and 2 as determined by polymerase chain reaction (PCR) assay. Resistance phenotypes comprised various combinations of seven antibiotics with a prevalence of ampicillin resistance in 63% of isolates (n = 56) from California, and tetracycline resistance in 37% of isolates (n = 62) from South Carolina. This disparity may be attributed to the differences in regional application of antibiotics as well as the origin of the waste materials in the compost itself. Phylogenetic PCR revealed that the majority of E. coli isolates (64%) belonged to groups A or B1. However, among these isolates, only 7% were resistant to two or more antibiotics as compared with 35% of isolates belonging to groups B2 and D. Integron detection by PCR revealed that nine (7.6%) E. coli isolates were positive for class I integrons, with six of the nine detected in isolates from groups B2 or D. Sequenced integrons (n = 5) were found to carry genes aadA, conferring reduced susceptibility to streptomycin, and dfrA, conferring resistance to trimethoprim. Our results suggest that E. coli isolates in compost belonging to phylogenetic groups B2 and D are more likely to contain integrons and higher levels of antibiotic resistance. The presence of multiple antibiotic resistances as well as integrons in E. coli implicates the potential for antibiotic resistance spread in the compost environment.

The objective of this study was to assess and differentiate wild-caught South Carolina (SC) shrimps from imported shrimps on the basis of microbiological analysis. Seven wild-caught SC shrimp and 13 farm-raised imported shrimp samples were analyzed. Total plate counts from wild-caught shrimp samples ranged from 4.3 to 7.0 log10 CFU/g, whereas counts from imported shrimp samples ranged from 3.2 to 5.7 log10 CFU/g. There was no difference (P > 0.05) between total bacterial counts of wild-caught SC shrimp and farm-raised imported shrimp. However, the percentages of bacteria with reduced susceptibility towards ceftriaxone and tetracycline were higher (P < 0.05) for farm-raised shrimp than for wild-caught samples. Salmonella spp. detected only in one farm-raised sample was resistant to ampicillin, ceftriaxone, gentamicin, streptomycin, and trimethoprim. Vibrio vulnificus was detected in both wild-caught and farm-raised shrimp samples; however, only the isolate from farm-raised shrimp was resistant to nalidixic acid and trimethoprim. Escherichia coli detected in one wild-caught sample was resistant to ampicillin. Both Listeria spp. and Salmonella spp. were absent with wild-caught SC samples. Therefore, the presence of more ceftriaxone- and tetracycline-resistant bacteria and the observed antimicrobial resistance phenotypes of isolates from the imported shrimp may reflect the possible use of antibiotics in raising shrimp in those countries.