Patients’ clinical information and isolates
In this study, two patients (Patients A and B) were included, and both patients underwent two ERCP operations. According to the operation records, the coherent endoscopes (TJF1-1 and TJF-4) were used in the operation sequentially; subsequently, these endoscopes were immediately suspended. The length of hospital stay of each patient is demonstrated in Figure 2.
Patient A was a 59-year-old male who was admitted following the complaint of abdominal pain on September 25, 2017 (Day 0). The patient was diagnosed with choledocholithiasis and cholecystitis. The patient underwent ERCP combined with endoscopic sphincterotomy, endoscopic papillary balloon dilatation, and nasobiliary drainage on Day 3 (TJF-1). Emergent ERCP was performed to stop the alimentary tract hemorrhage (Day 5, TJF-4). CRKP was isolated from the bile (Day 10, Isolates 295), blood (Day 11, Isolates 293) and nasobiliary duct (Day 11). Patient A was discharged at Day 24.
Patient B was a 70-year-old male who was admitted following the complaint of recurrent fever and abdominal distension on October 5, 2017 (Day 0). The patient was diagnosed with choledocholithiasis and acute cholangitis. The patient underwent ERCP twice to remove the calculus (Day 4, TJF-1 and Day 7, TJF-4). CRKP was isolated from the blood (Day 6, Isolates 299) and bile sample (Days 9 and 15), and carbapenem-resistant Pseudomonas aeruginosa was also isolated from the bile. Patient B was discharged at Day 27.
The two patients were both discharged from the hospital after an active and effective treatment.
Isolates from the environment and endoscope screening
The environment of the ERCP operation unit and the specific endoscope were screened 2 and 5 times for CRKP, respectively. The results of the first environmental screening are presented in Table 2, which showed that the environment was contaminated with CRKP. CRKP was isolated from one patient bed in the operating room (Isolate 23-2) and one touch screen of the high frequency electric knife (ERBE) (Isolate 10-2). Both isolates were stocked. Some environmental bacteria such as Bacillus spp. were identified in the operating room, specifically in the air outlet, lead curtains and clothes, touch screen, and pressure gage. Opportunistic pathogens such as Acinetobacter baumannii and Serratia marcescens were identified in the patient’s bed and water tank. The specimen obtained from the washing room was negative for bacteria.
Subsequently, VHP disinfection was performed after the first environmental screening, and the second environmental screening did not identify multidrug-resistant microbacteria. The environmentally contaminated bacteria such as Bacillus spp. disappeared, as presented in Table 2, and the other bacteria were not detected in the past positive location. Only the air outlet was still positive for bacteria (not identified), and this device should be paid careful attention because it is difficult to be disinfected.
To determine whether the endoscopes were contaminated, the TJF-1 and TJF-4 endoscope were screened for multidrug-resistant (MDR)-negative bacteria (Table 1). In October 27, the result showed that P. aeruginosa was identified from the TJF-1 endoscope, but K. pneumoniae was not detected. The OPA was used for routine endoscope disinfection before October 27, which indicated that the OPA was not effective. Subsequently, the disinfectant was changed to PAA and EO, and bacteria were already not detected during the four-time screening.
The results of MLST and PFGE
The isolates from the patients and environment were identified as CRKP, according to the susceptibility test by VITEK (Table 3). The results showed that the isolates were resistant to β-lactams, β-lactams/β-lactamase inhibitors, ciprofloxacin, and gentamycin. Amikacin, gentamycin, tobramycin, and tigecycline were susceptible in vitro. To determine the association between infectious patients and ERCP operation, all the isolates were detected by MLST and PFGE, and all of these five isolates belonged to ST11. The results of PFGE showed that the clinical isolates from the patients and the environmental isolates shared identical bands (Figure 3), which indicated that these isolates were closely associated with each other, and the CRKP infection might be due to these contaminated environments.
Retrospective case review
Considering these two cases, disinfection in the ERCP unit was significantly enforced, and subsequent cases of infection from November to May of the following year were monitored. One post-ERCP infection case was observed in November, December, and January, respectively, and none of the patients experienced infection after ERCP from February to May 2018.