To the Editor— Mitchell et alReference Mitchell, Dancer, Anderson and Dehn ¹ conducted a systematic review and meta-analysis to determine the risk of pathogen acquisition for patients associated with prior room occupancy. Overall, pooled acquisition odds ratio was 2.14 (95% confidence interval [CI], 1.65–2.77) for study pathogens: methicillin-resistant Staphylococcus aureus (MRSA); vancomycin-resistant enterococci (VRE); Clostridium difficile; Acinetobacter spp; extended-spectrum β-lactamase–producing coliforms; Pseudomonas spp. When comparing data between gram-positive and gram-negative organisms, the pooled acquisition odds ratios were 2.65 (95% CI, 2.02–3.47) for gram-negative organisms and 1.89 (95% CI, 1.62–2.21) for gram-positive organisms. Most of the included studies were performed in areas highly endemic for multidrug-resistant organisms (MDROs).

In January 2016, we initiated a prospective room surveillance project to determine whether the room is a risk factor for transmission to future occupants in a tertiary-care center with a low endemic MDRO burden. In addition, we considered rooms occupied by patients with symptomatic C. difficile or norovirus infection with a presumed high level of environmental contamination, for which a virucidal and sporicidal disinfectant was used for terminal cleaning and disinfection. Only routine infection control quality assurance or mandatory reportable surveillance data were used for this study, which was conducted according to German Federal Infection Prevention Law (IfSG) and German Federal Data protection law (Bundesdatenschutzgesetz).

All positive microbiological results of MDROs, Clostridium difficile, and norovirus cases were reported to the infection control registry. A likely case or room occupancy–associated transmission was defined as an occurrence of the same organism in a patient in the same room in the 6 weeks following discharge of a patient with known colonization or infection. For this report, we analyzed our experience during the first year of surveillance:

We identified 130 MDRO-cases: 95 MRSA, 9 MDR Escherichia coli, 9 MDR Pseudomonas aeruginosa, 5 MDR Klebsiella pneumoniae, 5 MDR Serratia marcescens, 2 MDR Enterobacter cloacae, 2 VRE, 1 MDR Acinetobacter baumannii, and 1 MDR Citrobacter freundii. Among these, 20 cases were classified as nosocomial according to current German surveillance definitions (www.nrz-hygiene.de) and 19 of these were not related to prior room occupancy.

A single case of MDR Klebsiella pneumoniae met inclusion criteria and was related to a small outbreak in the neonatal intensive care unit with transmission by a suctioning device.

We reported 7 cases of norovirus and 39 patients with C. difficile to the registry. A single norovirus case was nosocomial and 7 C. difficile cases were nosocomial, but none was related to prior room occupancy.

In contrast to previous studies,Reference Huang, Datta and Platt ² we could not demonstrate an increased risk for newly admitted patients to a room that had been occupied by a patient with an MDRO, C. difficile, or norovirus. Thus, we conclude that routine terminal cleaning and disinfection of all reachable surfaces in the room is sufficient to prevent the spread of these organisms, even in cases with a presumed high level of environmental contamination (eg, vomiting and diarrhea). The only case primarily linked to a room was falsely positive; it was part of a point-source outbreak not related to room cleaning or disinfection.

Our study is limited by the low endemic rate of MDRO and the lack of compliance checks of terminal cleaning procedures,Reference Clifford, Sparks and Hosford ^{3 ,} Reference Goodman, Platt, Bass, Onderdonk, Yokoe and Huang ⁴ but it reflects realistic daily practice in a large tertiary-care center in Germany. Enhanced cleaning and disinfections strategiesReference Anderson, Chen and Weber ⁵ may therefore only be necessary if the room is identified as a risk factor for transmission within an institution by surveillance such as ours.