Yushi Uetera

Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for species identification of Acinetobacter strains isolated from blood cultures

The clinical relevance of Acinetobacter species, other than A. baumannii, as human pathogens has not been sufficiently assessed owing to the insufficiency of simple phenotypic clinical diagnostic laboratory tests. Infections caused by these organisms have different impacts on clinical outcome and require different treatment and management approaches. It is therefore important to correctly identify Acinetobacter species. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been introduced to identify a wide range of microorganisms in clinical laboratories, but only a few studies have examined its utility for identifying Acinetobacter species, particularly those of the non-Acinetobacter baumannii complex. We therefore evaluated MALDI-TOF MS for identification of Acinetobacter species by comparing it with sequence analysis of rpoB using 123 isolates of Acinetobacter species from blood. Of the isolates examined, we identified 106/123 (86.2%) to species, and 16/123 (13.0%) could only be identified as acinetobacters. The identity of one isolate could not be established. Of the 106 species identified, 89/106 (84.0%) were confirmed by rpoB sequence analysis, and 17/106 (16.0%) were discordant. These data indicate correct identification of 89/123 (72.4%) isolates. Surprisingly, all blood culture isolates were identified as 13 species of Acinetobacter, and the incidence of Acinetobacter pittii was unexpectedly high (42/123; 34.1%) and exceeded that of A. baumannii (22/123; 17.9%). Although the present identification rate using MALDI-TOF MS is not acceptable for species-level identification of Acinetobacter, further expansion of the database should remedy this situation.

Microbial contamination of surgical instruments used for laparotomy

BACKGROUND The aim of this study was to determine the risk of contamination of surgical instruments according to the type of instrument and the surgical procedure. METHODS Microbiologic examination was conducted on 140 pairs of forceps used in 24 elective laparotomies. These included 60 pairs of tissue forceps and 80 pairs of DeBakey forceps. Microbes on their surface were recovered using a membrane filter method. Adenosine triphosphate assay was also performed simultaneously in each pair of forceps. RESULTS A total of 66 strains of microbes was recovered from 44 collected instruments (31%), with microbial counts ranging from 0 to 296 colony-forming units. Among the recovered microbes, gram-positive cocci were dominant [corrected]. The remaining microbes included 6 strains of gram-positive rods and 4 strains of gram-negative rods. The most common organism was Staphylococcus epidermidis, followed by S hominis and S warneri. Residual adenosine triphosphate was not correlated with the number of recovered microbes. CONCLUSION Surgical instruments tend to be contaminated during operations by microbes that inhabit the skin and organs. Surgical instruments could act as fomites for the pathogens of surgical site infection even if the surgical field is not apparently contaminated, through application of appropriate practices adhering to surgical site infection guidelines.

Prevention of medical accidents caused by defective surgical instruments

BACKGROUND The malfunctioning of surgical instruments may lead to serious medical accidents. Limited information is available on the risk of defective instruments. The purpose of these study is to demonstrate the features of defective surgical instruments, to establish a strategy to reduce the risk of medical accidents. METHODS We studied 19,474 consecutive operations during 2007 to 2009 at our hospital. The data on defective instruments were collected based on the orders for repair of broken instruments and reports of near-miss incidents. Adverse events caused by defective instruments were also identified from reports of near-miss incidents. RESULTS A total of 1,775 nonfunctioning instruments were identified during the study period. Of these, 112 were found during operation. More than half of the defective instruments were tissue-grasping instruments, bone-boring/gnawing instruments, and instruments for endoscopic surgery. Wearing out and inappropriate use of instruments were 2 major causes of defects. The rest of the causes consisted of inadequate inspection and factory defects. Two near-miss incidents (incidence 10 per 100,000 operations) in endoscopic surgery were potentially critical, but the postoperative course was uneventful in each patient. The incidence of defects adjusted by the number of operations demonstrated that bone-boring/gnawing instruments and instruments for endoscopic surgery tend to be broken during surgery. Without inspection by the manufacturer, the incidence would be much higher for endoscopic instruments. CONCLUSION Our data suggest that the appropriate use and adequate inspection of particular types of instruments are key for reducing the risk of medical accidents caused by defective surgical instruments.

Challenging Residual Contamination of Instruments for Robotic Surgery in Japan

BACKGROUND Recently, robotic surgery has been introduced in many hospitals. The structure of robotic instruments is so complex that updating their cleaning methods is a challenge for healthcare professionals. However, there is limited information on the effectiveness of cleaning for instruments for robotic surgery. OBJECTIVE To determine the level of residual contamination of instruments for robotic surgery and to develop a method to evaluate the cleaning efficacy for complex surgical devices. METHODS Surgical instruments were collected immediately after operations and/or after in-house cleaning, and the level of residual protein was measured. Three serial measurements were performed on instruments after cleaning to determine the changes in the level of contamination and the total amount of residual protein. The study took place from September 1, 2013, through June 30, 2015, in Japan. RESULTS The amount of protein released from robotic instruments declined exponentially. The amount after in-house cleaning was 650, 550, and 530 µg/instrument in the 3 serial measurements. The overall level of residual protein in each measurement was much higher for robotic instruments than for ordinary instruments (P<.0001). CONCLUSIONS Our data demonstrated that complete removal of residual protein from surgical instruments is virtually impossible. The pattern of decline differed depending on the instrument type, which reflected the complex structure of the instruments. It might be necessary to establish a new standard for cleaning using a novel classification according to the structural complexity of instruments, especially for those for robotic surgery. Infect Control Hosp Epidemiol 2017;38:143-146.

Novel concept of cleanliness of instruments for robotic surgery

Robotic systems for surgeryhavebeendevelopedover the last 30 years, and currently use of the da Vinci Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA) predominates in many countries. Robotic systems provide surgeons with many benefits such as refinedmanipulation of surgical instruments. On the other hand, they bring about difficulty for personnel in central sterile supply departments, because these instruments may be difficult or impossible to clean adequately. This article discussesconcernsabout thecleanlinessof robotic instruments.

A 5 Year Longitudinal Study of Water Quality for Final Rinsing in the Single Chamber Washer-Disinfector with a Reverse Osmosis Plant

This report deals with the construction and management of the reverse osmosis (RO) water system for final rinsing of surgical instruments in the washer-disinfector. Numerous operational challenges were encountered in our RO water system and these were analyzed utilizing the Ishikawa Fishbone diagram. The aim was to find potential problems and promote preventive system management for RO water. It was found that the measures that existed were inappropriate for preventing contamination in the heat-labile RO water system. The storage tank was found to be significantly contaminated and had to be replaced with a new one equipped with a sampling port and water drainage system. Additional filters and an UV treatment lamp were installed. The whole system disinfection started 1.5 years later using a peracetic acid–based compound after confirming the material compatibility. Operator errors were found when a new water engineer took over the duty from his predecessor. It was also found that there were some deficiencies in the standard operating procedures (SOPs), and that on-the-job training was not enough. The water engineer failed to disinfect the sampling port and water drainage system. The RO membrane had been used for 4 years, even though the SOP standard specified changing it as every 3 years. Various bacteria, such as Rothia mucilaginosa, were cultured from the RO water sampled from the equipment. Because Rothia mucilaginosa is a resident in the oral cavity and upper respiratory tract, it is believed that the bacteria were introduced into the system by the maintenance personnel or working environment. Therefore, the presence of R. mucilaginosa implied the failure of sanitary maintenance procedures. This study suggests that water systems should be designed based on the plans for profound system maintenance. It also suggests that SOP and on-the job training are essential to avoid any operator errors. These results must be carefully considered when either constructing new RO systems or performing maintenance and periodical examination of the equipment. LAY ABSTRACT: Reverse osmosis (RO) water is used for final rinsing in our washer-disinfector. The authors used the Ishikawa Fishbone diagram to clarify the critical points for optimizing RO water quality. There existed no measures to prevent contamination in the heat-labile RO water system. The storage tank was significantly contaminated and had to be replaced with a new one equipped with a sampling port and water drainage system. Additional filters and an UV treatment lamp were installed. The whole system disinfection started 1.5 years later using a peracetic acid–based compound after confirming the material compatibility. Operator errors occurred when a new water engineer took over the duty from his predecessor. There were neither standard operating procedures (SOPs) nor on-the-job training. The new water engineer had failed to disinfect the sampling port and water drainage system. Rothia mucilaginosa was cultured from the RO water. It is a resident in the oral cavity and upper respiratory tract. This implied the possible failure of sanitary procedures in the system maintenance. The Ishikawa Fishbone diagram was useful for this study. It suggests that water systems should be designed with plans for system maintenance taken into account. It also suggests that SOP and on-the job training are essential in order to avoid operator errors.

Role of Bacterial Biofilms in the Chemotherapy of Cholangitis with Brown Pigment Stones

The purpose of the present study was to clarify the role of biofilms in the chemotherapy of cholangitis. In 1 case of recurrent cholangitis with intrahepatic stones, the patient underwent right hepatectomy after chemotherapy was performed for 42 weeks. In the other case, chemotherapy including ciprofloxacin was performed during an attack of recurrent cholangitis. Repeated culture of bile specimens yielded negative results, whereas culture of the choledochal stone yielded Pseudomonas aeruginosa. We observed an acute transient IgM response to a component of the biofilm of P. aeruginosa (alginate) in this case. In both cases, electron microscopy revealed viable bacteria covered with biofilm in the component of brown pigment stones. It was concluded that biofilm is a factor of drug resistance.

Antimicrobial susceptibility profile of Acinetobacter species isolated from blood cultures in two Japanese university hospitals

Carbapenem‐resistant Acinetobacter baumannii has rapidly spread worldwide. This study investigated antibiotic susceptibility and genotypic resistance of 123 consecutive blood culture isolates of Acinetobacter species collected between 2003 and 2011 in two Japanese hospitals. The isolates were assigned to 13 species. Carbapenem resistance was detected in four isolates. Only one A. baumannii isolate had blaOXA‐23 together with ISAba1; the remaining three isolates had IMP‐1 metallo‐β‐lactamase. Quinolone resistance was detected in five isolates that had point mutations in the quinolone resistance‐determining region. The predominance of various non‐A. baumannii species and low prevalence of carbapenem resistance among blood culture isolates of Acinetobacter species in two Japanese hospitals were confirmed.

The Role of Heat-Tolerant Endotoxin-Retentive Ultrafilters (UFs) for the Remediation of Reverse Osmosis (RO) Plants Employed for Surgical Hand Antisepsis Using Periodic Thermal Disinfection—A Ten Year Longitudinal Experience Study in the Operating Theater

Recently, the use of filters has come into light for sanitizing water plants. This study investigated the role of heat-tolerant ultrafilters (UFs) for the remediation of reverse osmosis (RO) plants using periodic thermal disinfection. Two completely identical RO plants (RO plants A and B) were installed in 2006 for surgical hand antisepsis in the operating theater. RO water was stored in the 300 L storage tank and recirculated in the 190 meter-long loop delivering water to 12 faucets in each RO plant. Periodic thermal disinfection came into practice periodically when a UF module was retrofitted to the recirculation loop of each RO plant in 2010. Endotoxin was monitored closely before and after thermal disinfection. Before UF modules were retrofitted, endotoxin increased to a maximum of 0.301 EU/mL in RO plant A and 1.446 EU/mL in RO plant B after thermal disinfection, respectively. Since a UF module was retrofitted to each RO plant in 2010, endotoxin has been continuously below 0.025 EU/mL in RO plant A and exceeded this level five times in RO plant B. On one occasion, endotoxin increased in all samples collected simultaneously after solenoid valves were replaced in the recirculation loop near the air conditioner outlet. At this time, the inside of the pipework was exposed to the ventilation airflow. After the valves were replaced again, this time with the workplace isolated using a curing sheet, endotoxin decreased. On the other occasions, endotoxin increased only in one sample and decreased after thermal disinfection. Annually replaced UF modules were examined twice for estimating the amounts of immobilized endotoxin. The estimated amounts decreased in 2013 by the order of 10–3 in comparison with those in 2011 in both RO plants. The present study suggested that UFs acted synergistically with periodic thermal disinfection for the remediation of RO plants.

Concerns Associated With Cleaning Robotic Surgical Instruments—Response to Wallace

Affiliations: 1. Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 2. Managerial Epidemiology Research Center, Department of Public Health, School of Nursing and Midwifery, Maragheh University of Medical Sciences, Maragheh, Iran; 3. Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Address correspondence to Saeid Safiri, Assistant Professor of Epidemiology, Managerial Epidemiology Research Center, Department of Public Health, School of Nursing and Midwifery, Maragheh University of Medical Sciences, Maragheh, Iran (saeidsafiri@gmail.com). Infect Control Hosp Epidemiol 2017;38:1013–1014