Evaluation of pathogenicity and therapeutic effectiveness of antibiotics using silkworm Nocardia infection model.

Nocardia is a ubiquitous environmental microbe that causes nocardiosis against immunosuppressed and immunocompromised hosts. The assay system for the quantitative evaluation of virulence of Nocardia sp. or therapeutic effectiveness of antimicrobials for treatment of nocardiosis is not established so far. In this study, we established an infection model of Nocardia sp. using silkworm as an alternative animal model. We found that all tested Nocardia sp. such as Nocardia asiatica, Nocardia elegans, Nocardia exalbida, Nocardia farcinica, and Nocardia nova killed silkworm and their killing ability were different by species. N. farcinica showed higher pathogenicity among tested strain, similar to the mouse model as previously reported. In addition, we found that antimicrobials such as amikacin and minocycline showed therapeutic effectiveness in silkworms infected with N. farcinica, and we could determine effective doses 50 (ED50) values. These results suggest that silkworm is a useful alternative animal to evaluate the pathogenicity of Nocardia pathogen and the therapeutic effects of antimicrobials against Nocardia sp. in a quantitative manner.

Patient satisfaction with oral health check-ups at a community pharmacy and their effect on oral self-care habits and dental consultation behavior.

Maintaining good oral health is important because oral diseases are related to systemic diseases, and community pharmacies play a key role in maintaining the health of local residents. This study aimed to examine the effects of oral health check-ups and information provision at community pharmacies on oral health-associated behaviors as well as patient satisfaction. We conducted oral health check-ups and provided information about oral health self-care to 84 patients at a community pharmacy, and then asked them to complete a questionnaire survey. One month later, we sent them a follow-up questionnaire and received responses from 66.7% (56/84) of the participants. The large majority were satisfied with the salivary test (95.2%) and the information (96.4%) we provided. Most of the participants (89.3%) indicated that they wanted to use the oral health check-up service again in the future. Compared with baseline, the ratio of participants restricting their intake of sugar-rich foods and drinks significantly increased 1 month later (p = 0.021). About 60% of those who had not undergone a regular dental examination at baseline reported newly visiting or planning to visit a dental clinic. The results revealed high satisfaction with the oral health check-up and information about oral self-care they received at the community pharmacy. The results suggested that oral health check-ups had the potential to change both oral self-care habits and dental consultation behavior. Our findings indicate that community pharmacies can contribute to the maintenance and promotion of oral health by providing oral health check-ups to local residents.

Prevalence of ESBL-producing Escherichia coli and carbapenem-resistant Enterobacteriaceae in treated wastewater: a comparison with nosocomial infection surveillance.

The increasing prevalence of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli and carbapenem-resistant Enterobacteriaceae (CRE) is a worldwide health threat. Monitoring of these resistant bacteria in the environment can provide regional prevalence reflecting both healthy and infected populations, although the quantitative monitoring of those resistant bacteria, especially CRE, is difficult due to their low proportion in the total Enterobacteriaceae population and the possible interference by autochthonous species with intrinsic resistance. In this study, these resistant bacteria in treated wastewater were quantified at 12 different treatment plants. The proportions of cefotaxime-resistant and ESBL-producing E. coli in the total E. coli population in the chlorinated effluents in Tokyo were 5.7 and 5.3%, respectively. The estimated proportion of CRE was 0.007% with the constituting species of Klebsiella spp. and Enterobacter spp., although the conditions during the first incubation may have affected the estimation even after the correction by the proportion of resistant population in the isolates. The observed resistant proportions in this study were lower than those in the surveillance on nosocomial infection not only for inpatients but also for outpatients, and higher than those in the veterinary monitoring.

Clinical and microbiological characteristics and occurrence of Klebsiella pneumoniae infection in Japan.

PURPOSE: Klebsiella pneumoniae is a pathogen that causes pneumonia and urinary tract infection. Hypervirulent K. pneumoniae strains often show hypermucoviscosity, are of the K1 or K2 serotype, and harbor the rmpA and magA genes. However, the differences in the prevalence of K. pneumoniae with these hypervirulent characteristics between the infection and colonization status are not well understood. Therefore, in this study, we compared the clinical and microbiological characteristics of K. pneumoniae isolated from urine or sputum samples of cases of infection and colonization. PATIENTS AND METHODS: This retrospective study was conducted at a tertiary care teaching hospital in Tokyo, Japan. Patients whose sputum or urine tested positive for the presence of K. pneumoniae isolates were randomly included in the study. Clinical and microbiological data were collected from medical records. RESULTS: Of the 130 cases investigated, 68 and 62 cases showed the presence of K. pneumoniae in the sputum and urine, respectively. There were 49 infection cases, including 21 in the sputum group and 28 in the urine group. The infections were not accompanied by liver abscess. Of the 130 K. pneumoniae isolates, 25 (19.2%) showed capsular serotype K1 or K2, whereas 33 (25.4%) showed hypermucoviscosity. The prevalence of virulence genes magA, allS, rmpA, mrkD, uge, kfu-BC, and wabG was 10% (all in K1), 13.1%, 16.9%, 85.4%, 79.2%, 36.9%, and 91.5%, respectively. In both the sputum and urine groups, there was no difference in the characteristics of patients with infection and those with colonization. Analysis of microbiological characteristics revealed that only rmpA was significantly more frequent in the infection cases than in the colonization/asymptomatic cases in both the sputum and urine groups. CONCLUSION: The rmpA-positive K. pneumoniae isolates were dominant in the infection cases compared with those in the colonization/asymptomatic cases, suggesting that rmpA may play a crucial role in the development of urinary tract infection and pneumonia.

D-cycloserine increases the effectiveness of vancomycin against vancomycin-highly resistant Staphylococcus aureus.

Vancomycin is a widely used clinical drug to treat for infection by methicillin-resistant Staphylococcus aureus. Some patients show a weak response to vancomycin treatment. We previously reported that ß-lactams increase the susceptibility to vancomycin by vancomycin-highly resistant S. aureus (VRSA) strains obtained following repeated in vitro mutagenesis and vancomycin selection. Here we found that the susceptibility of the VRSA strains to vancomycin was remarkably increased by combined treatment with D-cycloserine. On the other hand, VRSA did not show increased susceptibility to vancomycin in combination with bacitracin, fosfomycin, erythromycin, lincomycin, gentamicin, levofloxacin or nisin. Furthermore, in an in vivo infection model with silkworms, combined treatment with vancomycin and D-cycloserine exhibited therapeutic effects, whereas treatment with each compound alone did not. These findings suggest that combined treatment with vancomycin and D-cycloserine could be therapeutically effective against infectious diseases caused by VRSA.

Antimicrobial susceptibility testing of rapidly growing mycobacteria isolated in Japan.

BACKGROUND: Difficult-to-treat infections caused by rapidly growing mycobacteria (RGM) are increasingly observed in clinical settings. However, studies on antimicrobial susceptibilities and effective treatments against RGM in Japan are limited. METHODS: We conducted susceptibility testing of potential antimicrobial agents, including tigecycline and tebipenem, against RGM. Clinical RGM isolates were collected from a university hospital in Japan between December 2010 and August 2013. They were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and the sequencing of 16S rRNA, rpoB, and hsp65 genes. The samples were utilized for susceptibility testing using 16 antimicrobials, with frozen broth microdilution panels. RESULTS: Forty-two isolates were obtained: 13, Mycobacterium abscessus complex; 12, Mycobacterium chelonae; 9, Mycobacterium fortuitum; and 8, M. fortuitum group species other than M. fortuitum. Different antimicrobial susceptibility patterns were observed between RGM species. Clarithromycin-susceptible strain rates were determined to be 0, 62, and 100% for M. fortuitum, M. abscessus complex, and M. chelonae, respectively. M. abscessus complex (100%) and >80% M. chelonae isolates were non-susceptible, while 100% M. fortuitum group isolates were susceptible to moxifloxacin. Linezolid showed good activity against 77% M. abscessus complex, 89% M. fortuitum, and 100% M. chelonae isolates. Regardless of species, all tested isolates were inhibited by tigecycline at very low minimal inhibitory concentrations (MICs) of ≤0.5 µg/mL. MICs of tebipenem, an oral carbapenem, were ≤4 µg/mL against all M. fortuitum group isolates. CONCLUSIONS: Our study demonstrates the importance of correct identification and antimicrobial susceptibility testing, including the testing of potential new agents, in the management of RGM infections.

Synergistic effects of vancomycin and ß-lactams against vancomycin highly resistant Staphylococcus aureus.

We previously reported isolating vancomycin (VAN) highly resistant Staphylococcus aureus (VRSA) strains from clinical methicillin-resistant S. aureus strains by repeating steps of in vitro mutagenesis and VAN selection. Here we describe that the in vitro susceptibility of these VRSA strains to VAN was markedly increased by combined treatment with ß-lactams such as ceftriaxone and oxacillin. Furthermore, in an in vivo silkworm infection model with VRSA, a combination of VAN and ceftriaxone exhibited therapeutic effects, whereas a combination of VAN and oxacillin did not. These findings suggest that combining VAN with an appropriate ß-lactam, such as ceftriaxone, is therapeutically effective against infectious diseases caused by VRSA.

Analysis of spontaneous inquiries about suspected adverse drug reactions posted by the general public on the electronic Japanese bulletin board "Yahoo! Japan Chiebukuro".

PURPOSE: Spontaneous inquiries about the development of adverse drug reactions (ADRs) to medicines can be extracted based on the questions posted by the general public on the electronic Japanese bulletin board "Yahoo! Japan Chiebukuro". Our aim was to clarify the characteristics related to people's descriptions of suspected ADRs and determine the reasons for submitting a spontaneous inquiry. METHODS: Fifty brand names of medicines used for inquiry extraction were chosen by selecting 35 pharmaceutical products, based on the generic names that had the highest sales in Japan. Questions containing both the brand name of one of these medicines and the term "Fukusayo" (ADR in Japanese) that were posted from July 2004 to June 2009 were extracted from the site. RESULTS: Among 1,419 questions extracted, 614 questions had at least one identifiable brand name of a suspected medicine, an ADR description, and the extent to which the ADR appeared to be caused by the suspected medicine(s). Among these 614 questions, 589 described in detail the symptoms/signs that the inquirers themselves or their families had experienced as ADRs. The highest number of questions was found for Paxil (525). Posts asking whether the symptoms being experienced were due to an ADR accounted for the highest number of questions. In most cases, the inquirer suspected that a single medicine led to an ADR and was seeking advice from others taking the same medicine. CONCLUSION: Our examination of spontaneous inquiries showed that people have sufficient knowledge to adequately report potential ADRs in terms of their symptoms, suspected medicines, and the disease for which the medicine was used. However, they often did not describe the start time when the ADR appeared or when the suspected medicine was started.

Phenotypic and genomic comparisons of highly vancomycin-resistant Staphylococcus aureus strains developed from multiple clinical MRSA strains by in vitro mutagenesis.

The development of vancomycin (VCM) resistance in Staphylococcus aureus threatens global health. Studies of the VCM-resistance mechanism and alternative therapeutic strategies are urgently needed. We mutagenized S. aureus laboratory strains and methicillin-resistant S. aureus (MRSA) with ethyl methanesulfonate, and isolated mutants that exhibited high resistance to VCM (minimum inhibitory concentration = 32 µg/ml). These VCM-resistant strains were sensitive to linezolid and rifampicin, and partly to arbekacin and daptomycin. Beta-lactams had synergistic effects with VCM against these mutants. VCM-resistant strains exhibited a 2-fold increase in the cell wall thickness. Several genes were commonly mutated among the highly VCM-resistant mutants. These findings suggest that MRSA has a potential to develop high VCM resistance with cell wall thickening by the accumulation of mutations.

Clinical characteristics and antimicrobial susceptibility of Bacillus cereus blood stream infections.

BACKGROUND: Bacillus cereus is one of the pathogens causing nosocomial bloodstream infections (BSIs). However, few reports have documented the antimicrobial susceptibility and clinical characteristics of Bacillus cereus BSI and the importance of empirical therapy. The aim of this study was to investigate the clinical characteristics and antimicrobial susceptibility of B. cereus isolates from patients with BSI and to analyze the impact of appropriate empirical therapy on the outcome of patients with B. cereus BSI. METHODS: All adult cases of bacteremia between April 2003 and March 2012 in a teaching hospital in Tokyo, Japan were reviewed retrospectively. Clinical data were collected from the patients' medical records and charts. Antimicrobial susceptibility testing was performed by broth microdilution method. The patients with B. cereus BSI were divided into an appropriate empirical therapy group and an inappropriate empirical therapy group. The primary outcome was all-cause mortality at 4 weeks after the start of BSI. The secondary outcome was early defervescence within 2 days after starting empirical therapy. RESULTS: There were 29 B. cereus bloodstream infection cases. No vancomycin, gentamicin, and imipenem-resistant isolates were found. However, 65.5 % were resistant to clindamycin and 10.3 % were resistant to levofloxacin. The main etiology was venous catheter-related (69 %). All-cause mortality at 4 weeks was not significantly different between the appropriate empirical therapy group (9 cases) and the inappropriate group (20 cases) in this study. However, early defervescence within 2 days after starting empirical therapy was significantly different (p = 0.032). CONCLUSIONS: The BSI of B. cereus is mostly caused by venous catheter-related infections. Appropriate empirical therapy is important to achieve early clinical resolution in B. cereus BSI. Vancomycin is one of the appropriate selections of empirical therapy for B. cereus BSI.

Antibiotic Susceptibilities of Pseudomonas aeruginosa Isolated from Blood Samples and Antibiotic Utilization in a University Hospital in Japan.

INTRODUCTION: Pseudomonas aeruginosa is one of the most important causes of nosocomial infection. Several reports indicated a correlation of antimicrobial usages and declined susceptibilities. In this report, we evaluated their relation in a tertiary care teaching hospital in Tokyo, Japan for 4 years. METHODS: We evaluated the susceptibilities of 149 strains of P. aeruginosa isolated from blood samples and consumption of anti-pseudomonal antibiotics as antimicrobial use density from 2009 to 2012 in the University of Tokyo Hospital in Tokyo, Japan. RESULTS: Usages of carbapenems and anti-pseudomonal cephalosporins decreased 44% and 31% from 2009 to 2011, and then increased 30% and 24% in 2012, respectively. Usage of piperacillin-tazobactam increased 87% from 2009 to 2012, which was introduced in the hospital in 2008. Consumption of fluoroquinolones and aminoglycoside remained low in those years. Susceptibilities to cephalosporins, carbapenems (except for panipenem-betamipron), penicillins, and fluoroquinolones declined between 22% and 39% in 2010, increased in the range of 16-31% in 2011, and increased by 1-14% in 2012. Susceptibility of panipenem-betamipron ranged between 25% and 32%. Susceptibility to aminoglycoside was more than 90% during this period. No relationship between antimicrobial usages and susceptibilities of P. aeruginosa was observed. CONCLUSION: Susceptibilities of P. aeruginosa did not correlate with the usage of antibiotics in our hospital. Several infection control measures and other factors might contribute to changing the susceptibilities of bacteria.

Nationwide surveillance of bacterial respiratory pathogens conducted by the surveillance committee of Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2010: General view of the pathogens' antibacterial susceptibility.

The nationwide surveillance on antimicrobial susceptibility of bacterial respiratory pathogens from patients in Japan, was conducted by Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases and Japanese Society for Clinical Microbiology in 2010. The isolates were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections during the period from January and April 2010 by three societies. Antimicrobial susceptibility testing was conducted at the central reference laboratory according to the method recommended by Clinical and Laboratory Standard Institutes using maximum 45 antibacterial agents. Susceptibility testing was evaluable with 954 strains (206 Staphylococcus aureus, 189 Streptococcus pneumoniae, 4 Streptococcus pyogenes, 182 Haemophilus influenzae, 74 Moraxella catarrhalis, 139 Klebsiella pneumoniae and 160 Pseudomonas aeruginosa). Ratio of methicillin-resistant S. aureus was as high as 50.5%, and those of penicillin-intermediate and -resistant S. pneumoniae were 1.1% and 0.0%, respectively. Among H. influenzae, 17.6% of them were found to be ß-lactamase-non-producing ampicillin (ABPC)-intermediately resistant, 33.5% to be ß-lactamase-non-producing ABPC-resistant and 11.0% to be ß-lactamase-producing ABPC-resistant strains. Extended spectrum ß-lactamase-producing K. pneumoniae and multi-drug resistant P. aeruginosa with metallo ß-lactamase were 2.9% and 0.6%, respectively. Continuous national surveillance of antimicrobial susceptibility of respiratory pathogens is crucial in order to monitor changing patterns of susceptibility and to be able to update treatment recommendations on a regular basis.

Patients views and experiences in online reporting adverse drug reactions: findings of a national pilot study in Japan.

BACKGROUND: Patients have been allowed to report adverse drug reactions (ADRs) directly to the government in some countries, which would contribute to pharmacovigilance. OBJECTIVE: We started a pilot study to determine whether web-based patient ADR reporting would work in Japan. This article aims to describe the characteristics of the patient reporters, and to clarify patient views and experiences of reporting. METHODS: Patients who submitted online ADR reports were contacted to respond to an ADR reporting questionnaire; only consenting reporters were included. Subjects with multiple responses were excluded from analysis. The questionnaire consisted of both closed and open questions. Questionnaire responses were examined using Pearson's chi-squared test. RESULTS: A total of 220 web-based ADR reports were collected from January to December 2011; questionnaires were sent to 190 reporters, excluding those who gave multiple reports and those that refused to be contacted. Responses were obtained from 94 individuals (effective response rate: 49.5%). The median respondent age was 46.0 years. Sixty-three respondents found out about this pilot study on the Internet (67.0%). The numbers of respondents claiming that they had difficulty recalling the time/date of ADR occurrence were 16 patient reporters and three non-patient reporters. The number of reporters who found it difficult to complete the online reporting form was 22 patients (26.2%) and one non-patient (10%). Fifty-seven respondents (60.6%) expected feedback after reporting and many respondents wanted to know the process of ADR data collection and related information. Seventy-three respondents (77.7%) stated that they would report ADRs again in future. CONCLUSION: Throughout the entire questionnaire, online patient ADR reporting was received with a forward-looking, positive approach. To facilitate smoother web-based reporting experiences in future, some improvements may be required in online ADR reporting forms, particularly with regard to respondent feedback.

A Case of Liver Abscess with Desulfovibrio desulfuricans Bacteremia.

Desulfovibrio spp. are gram-negative, sulfate-reducing, and anaerobic bacteria found in the digestive tract of humans. Because Desulfovibrio spp. are infrequent causative agents of infectious diseases and are difficult to isolate and to identify from clinical specimens, the appropriate antibiotic therapy to infection with Desulfovibrio spp. has not been determined. We report the first case of liver abscess with bacteremia due to Desulfovibrio desulfuricans to show the clinical presentation and treatment. The patient was successfully treated with intravenous piperacillin-tazobactam and oral amoxicillin-clavulanic acid.

[Effects of the new comprehensive system for designating illegal drug components on the abuse of designer drugs and future problems based on an online questionnaire].

Recently, the abuse of designer drugs has become a social problem. Designer drugs are created by modifying part of the chemical structure of drugs that have already been categorized as illegal, thereby creating a different chemical compound in order to evade Pharmaceutical Affairs Law regulations. The new comprehensive system for designating illegal drug components has been in effect since March 2013, and many designer drugs can now be regulated. We conducted an online questionnaire survey of people with a history of designer drug use to elucidate the effects of the new system on the abuse of designer drugs and to identify potential future problems. Over half the subjects obtained designer drugs only before the new system was implemented. Awareness of the system was significantly lower among subjects who obtained designer drugs for the first time after its introduction than those who obtained the drugs only before its implementation. Due to the new system, all methods of acquiring designer drugs saw decreases in activity. However, the ratio of the acquisition of designer drugs via the Internet increased. Since over 50% of the subjects never obtained designer drugs after the new system was introduced, goals that aimed to make drug procurement more difficult were achieved. However, awareness of the new system among subjects who obtained designer drugs after the new system was introduced was significantly low. Therefore, fostering greater public awareness of the new system is necessary. The results of the questionnaire also suggested that acquiring designer drugs through the Internet has hardly been affected by the new system. We strongly hope that there will be a greater push to restrict the sale of designer drugs on the Internet in the near future.

Diversity of vancomycin-resistant enterococci in a low endemicity area.

Although vancomycin-resistant enterococci (VRE) are frequent nosocomial pathogens worldwide, in Japan their prevalence is low and their molecular epidemiology remains unclear. In The University of Tokyo Hospital (Tokyo, Japan), only five isolates of VRE (vanA-type Enterococcus faecium) were identified in the 20 years before 2010; however, nine isolates of vanB-type E. faecium were identified from 2011 to 2012. Multilocus sequence typing (MLST) revealed that they belonged to five sequence types (ST18, ST78, ST203, ST412 and ST612). Despite the limited isolation, including one from a medical tourist, there was significant diversity in genotypes. Increasing medical travel might enhance the diversity of VRE.

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.