1134 infection control & hospital epidemiology october 2015, vol. 36, no. 10
table 1. Detection of Nonspecific Biomaterial Before and After Cleaning
+/+ +/––/+ –/–
Biomaterial Type No. % No. % No. % No. % 16S
BAP MAC
NOTE. 16S, non–species specific; BAP, blood agar plate; MAC, MacConkey agar plate.
table 2. Number of Surfaces That Tested Positive for Any Target Organism
Cultureb Surface Type (No.)a
Bathroom door closer (77) 3 Bathroom light switch (77) 1 Bathroom sink (77) Bedpan cleaner (77) Bedside table (76) Call box (75) IV pole (60)
Room chair (74)
Room door closer (77) Room light switch (74) Room sink (74) Side rail (73)
Telephone (75) Toilet handle (77) Toilet rail (77) Toilet seat (77) Tray table (76) Total (1273)
PCRc
Before Both After Before Both After 1 3
0 2
15 1 1 1 2 3 2 0 1
3 2 4 3
4 1 5 6 1
3 9 1 1 3 2 0 3 2 2 1 5 1 3 0 0 1 1
4 5 1 0 0 0 0 0 2
2 4 1 4 6 1 5
25 58
0 0 4 2 3 0 3 4 0 2 6 0 0 3 8 2 4
55 4 21 53 5 41 59
46
NOTE. PCR, polymerase chain reaction; IV, intravenous therapy. aFor each surface, 2 swabs were obtained, 1 before cleaning and 1 after
cleaning. bIndividual surfaces from which any target organism was cultured.
Before=tested positive before, but after, room cleaning; After= tested positive only after cleaning; Both=tested positive before and after cleaning. The total number of surfaces that tested positive prior to cleaning is the sum of the sum of the “Before” and “Both” columns. The total number of surfaces that tested positive after cleaning is the
sum of the sum of the “After” and “Both” columns. cIndividual surfaces that tested positive for any target organism by PCR.
before, but not after, terminal cleaning; 21 harbored TOs after, but not prior to, cleaning; and 4 surfaces (3 different surface types) had cultivable TOs both before and after cleaning (Table 2). Cleaning resulted in fewer detection incidents on all surfaces but room sinks, on which detection events increased from 5 to 6 after cleaning (Table 2).Among individual surfaces, only bathroom sinks showed a significant reduction in
305 24.02 273 21.50 183 14.41 509 40.08 361 28.43 341 26.85 132 10.39 436 34.33 56 4.41 139 10.94 87 6.85 988 77.80
cultivable TOs after cleaning (P=.0004 for a 1-tailed test). Total cTO detection events decreased from 59 to 25 (58% reduction) after cleaning (P=4.88×10-7 for a 1-tailed test) (Table 2). Molecular-based detection of TO after cleaning. TOs were
detected by species-specific PCR on 99 surfaces (Table 2). In total, 53 surfaces with TOs before room cleaning lacked them afterward, while 41 surfaces without PCR-detectable TOs prior to cleaning tested positive after cleaning. In total, 5 surfaces (of 4 surface types) tested positive for TO DNA both before and after cleaning (Table 2). Cleaning resulted in more incidents detected on 5 surface
types: room chair (3 precleaning vs 4 postcleaning); room light switch (1 vs 2); room sink (6 vs 7); toilet handle (2 vs 3); and toilet rail (5 vs 9) (Table 2). Total detection events by species- specific PCR decreased from 58 to 46 (21% reduction) with cleaning, but this change was not significant (P=.0616 for a 1-tailed test), suggesting that cleaning did not reliably remove all TO DNA (Table 2). Correlations among environmental contamination with MDR-TOs, TOs, and HAI. No infections were caused by A. baumannii or C. difficile over the study period. The most common non-MDR TO infection was S. aureus (n=77), followed by E. coli (n=56), K. pneumoniae (n=28), and P. aeruginosa (n=11). The only statistically significant correlation between TO infection and environmental presence of a cultivable TO was for Enterococcus spp. (1-tailed Pearson correlation P=.020; 1-tailed Poisson regression P=.035) (Figure 3). No significant correlations were observed between PCR-detected environmental TOand analogousHAIs except for inpatient E. coli infections and the detection of environmental E. coliDNA (1-tailed Pearson correlation P=.001; 1-tailed Poisson regression P=.002) (Figure 3). The only cultivable environmental MDR-TO was MRSA, which was recovered from 2 terminally cleaned surfaces 7 months after patients and staff arrived at the hospital. A single isolate was collected from a thoroughly cleaned (≤10% DAZO detection) toilet rail, the other was collected from a poorly cleaned (≥10% DAZO detection) call box. Another MRSA was isolated from the respiratory tract of a patient hospitalized on the same ward
5months later (12months after opening). According to pulsed- field gel electrophoresis (PFGE), the environmental and infection-derived strains were related (96.3% identical) (Supplemental Figure 1). However, WGS revealed that environmental isolates were genetically identical to each other butwere unrelated to the isolates from patient infections because they differed by 126 SNPs, 13 insertions/deletions, and the presence of a prophage.
discussion
Environmental TO peaked early in the surveillance period and then plateaued. Environmental MDR-TOs were rarely isolated and were not implicated in HAIs. The rate of cleaning thoroughness at this facility (43%) was consistent with
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