Yoshiki Misawa

Evaluation of a simple phenotypic method for the detection of carbapenemase-producing Enterobacteriaceae.

We investigated the performance of a phenotypic test, the Carbapenemase Detection Set (MAST-CDS), for the identification of carbapenemase-producing Enterobacteriaceae. Our results indicated that MAST-CDS is rapid, easily performed, simple to interpret, and highly sensitive for the identification of carbapenemase producers, particularly imipenemase producers.

First reported case of Staphylococcus condimenti infection associated with catheter-related bacteraemia

We report a case of a patient who experienced a catheter-related bloodstream infection caused by Staphylococcus condimenti, which was first isolated from soy sauce mash. This is the first reported case of human infection. Although blood culture isolates and the catheter tip tube did not reveal coagulase or clumping factor, false-positive results were obtained from latex agglutination tests for clumping factor and protein A due to self-agglutination. Care is needed when performing only latex agglutination test without a coagulase test. Further studies are needed to determine the pathogenic potential of S. condimenti based on appropriate identification.

A case of severe necrotizing cellulitis caused by group G Streptococcus dysgalactiae subsp. equisimilis

Group G streptococcus (GGS) is infrequently associated with severe invasive soft tissue infection and toxic shock syndrome. A 74-year-old woman with a history of lymphedema of the lower extremities after surgical and radiation therapy for uterine cancer and diabetic mellitus and admitted for swelling of the right leg, fever, and dyspnea. She presented with shock and necrotizing cellulitis of the right lower extremity. Laboratory tests showed leukocytepenia, acute renal and liver dysfunction, and muscle damage. She rapidly developed multiple organ failure and necrotizing cellulitis. A swab from skin vesicle, throat, and blood culture grew Group G Streptococcus dysgalactiae subsp. equisimilis. Despite endotoxin hemoadsorption therapy, administration of antibiotics, and intravenous immunoglobulin, she died 9 days after admission due to toxic shock syndrome caused by GGS. The M-protein gene (emm) typing of GGS isolated from both blood and skin lesion showed stG 485.0. Three virulence genes, sagA, slo and skcg, were detected from GGS isolated from them.

Diagnosing Clostridium difficile-associated diarrhea using enzyme immunoassay: the clinical significance of toxin negativity in glutamate dehydrogenase-positive patients

Purpose The enzyme immunoassay (EIA) has lower sensitivity for Clostridium difficile toxins A and B than the polymerase chain reaction in the diagnosis of C. difficile-associated diarrhea (CDAD). Furthermore, toxin positivity with EIA performed on C. difficile isolates from stool cultures may be observed even in patients with EIA glutamate dehydrogenase (GDH)-positive and toxin-negative stool specimens. It is unclear whether such patients should be treated as having CDAD. Methods The present study retrospectively compared patient characteristics, treatment, and diarrhea duration among three groups of patients who underwent stool EIA testing for CDAD diagnosis: a toxin-positive stool group (positive stool group; n=39); a toxin-negative stool/toxin-positive isolate group (discrepant negative/positive group, n=14); and a dual toxin-negative stool and isolate group (dual negative group, n=15). All cases included were confirmed to be GDH positive on EIA test. Results Patients’ backgrounds and comorbidities were not significantly different among three groups. No difference was observed among the three groups with regard to antimicrobial drug use before diarrhea onset. Treatment was received by 82.1% of the positive stool group compared to 7.1% of the discrepant positive/negative group and 0% of the dual negative group, while mean diarrhea duration was 10.6 days compared to 7.9 days (P=0.6006) and 3.4 days (P=0.0312), respectively. Conclusion Even without treatment, patients with toxin-negative stool specimens had shorter diarrhea duration than those with toxin-positive stool specimens even with toxin-positive isolates. These findings may suggest a limited need for CDAD treatment for GDH-positive patients and toxin-negative stool specimens.

Nontraumatic keratomycosis caused by Alternaria in a glaucoma patient

A case of keratomycosis caused by Alternaria species in a patient with glaucoma is reported. A 55-year-old Japanese man who had been followed for developmental glaucoma presented with corneal ulcer in his right eye, which did not respond to antibacterial agents. There was no history of traumatic episode. Culture on potato dextrose agar from corneal scraping yielded Alternaria species. Topical amphotericin B treatment achieved recovery from ulceration although the corneal opacity remained.

Fatal fungal endocarditis by Aspergillus udagawae: an emerging cause of invasive aspergillosis

Aspergillus udagawae has morphological similarities to Aspergillusfumigatus; however, it shows a low susceptibility to common antifungal drugs and poor in vitro sporulation. We present the first reported case of infectious endocarditis caused by A. udagawae. An awareness of this newly described Aspergillus species is vital for further clarification.

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.

Scedosporium prolificans Endocarditis: Case Report and Literature Review.

Scedosporium prolificans, a hyaline filamentous fungus, is widely distributed in the environment and is currently an emerging human pathogen, especially among immunocompromised patients. However, S. prolificans endocarditis is rare. We herein report a case of S. prolificans endocarditis in a 64-year-old patient with breast cancer in complete remission for 30 years after chemotherapy and radiation treatment who was not cured. Susceptibility testing showed resistance to all antifungal drugs, except echinocandin. A review of the literature revealed 10 cases of S. prolificans endocarditis; of these, only one involved an immunocompetent host with no risk factors and only two patients survived. In order to improve the mortality rate, it is necessary to establish rapid diagnostic methods and efficient therapeutic approaches.

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.