TABLE 1.

Prevalence of ARB HPC in source water, finished drinking water, and tap water from four townsa

SamplebTotal HPC (CFU/100 ml)% of total HPC resistant to:
AmoxicillinCiprofloxacinChloramphenicolGentamicinRifampinSulfisoxazoleTetracycline
RW-P1.19 × 10611.67 ± 4.3911.60 ± 5.924.17 ± 1.9314.42 ± 5.5210.85 ± 3.577.46 ± 3.871.66 ± 0.80
DW-P6839.55 ± 9.79c4.77 ± 4.7119.45 ± 5.60c21.96 ± 14.4347.98 ± 17.99c1.17 ± 1.14c1.50 ± 1.24
TW-11.6 × 10415.22 ± 2.73d9.99 ± 4.7613.96 ± 3.70c13.40 ± 1.7362.00 ± 8.96c3.34 ± 1.213.78 ± 0.93c,d
TW-26.04 × 1043.02 ± 0.1913.14 ± 0.485.49 ± 0.474.67 ± 0.2128.10 ± 1.727.85 ± 0.670.08 ± 0.01
TW-33.44 × 1024.07 ± 0.170.18 ± 0.070.75 ± 0.392.18 ± 0.6282.15 ± 1.500.33 ± 0.030.98 ± 0.38
TW-42.46 × 10314.33 ± 1.740.18 ± 0.052.05 ± 0.049.76 ± 0.3414.23 ± 1.690.12 ± 0.0010.04 ± 0.002
  • a Prevalence was defined as the percentage of resistant HPC in the total HPC. The statistical analysis was done using six samples for each type and four technical replicates for each sample.

  • b RW-P, source water from the drinking water treatment plant; DW-P, finished drinking water from the drinking water treatment plant; TW-1, tap water from the city where the drinking water treatment plant is located; TW-2, TW-3, and TW-4, tap water from three towns in Michigan and Ohio close to the city where the TW-1 drinking water treatment plant is located.

  • c Significantly different from RW-P.

  • d Significantly different from DW-P.