Autochthonous Cryptococcus gattii genotype VGIIb infection in a Japanese patient with anti-granulocyte-macrophage colony-stimulating factor antibodies.

A 31-year-old Japanese man presented with cerebral and pulmonary cryptococcosis. Cryptococcus gattii (C. gattii) genotype VGIIb was detected in the patient's sputum and cerebrospinal fluid specimens. The serum levels of anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibodies were elevated in this patient, which has been associated with pulmonary alveolar proteinosis and is considered a risk factor for C. gattii infection. After undergoing >12 months of antifungal treatments, the patient showed improvements in symptoms and findings on brain and lung imaging. Several Japanese patients who develop C. gattii infection have also been reported; however, most of these patients have been infected outside Japan, as C. gattii infection is rare in Japan. Only one patient with C. gattii genotype VGIIb infection has been reported in Japan, and it is believed that this patient contracted the infection in China. In the present case, our patient has never been outside Japan, indicating that the infection originated in Japan. Our findings suggest that C. gattii might be spreading in Japan. Therefore, patients with positive serum anti-GM-CSF antibodies should be thoroughly monitored for C. gattii infection, even those living in Japan.

Characteristics of pediatric patients claimed with acute upper respiratory infection during otorhinolaryngology consultations: A descriptive study of a large Japanese medical claims database.

This study aimed to clarify other diseases claimed simultaneously with acute upper respiratory infection (URI), antibiotic prescriptions, and examinations associated with infectious diseases in pediatric patients with acute URI insurance claims at otorhinolaryngology outpatient visits. Pediatric patients who visited an otolaryngology department between 2019 and 2021 and were definitively diagnosed with URI were selected using a large Japanese medical claims database. Patient backgrounds, antibiotic use, and examinations were descriptively evaluated. In total, 8010 patients were included in the analysis. The median number (interquartile range) of diseases claimed in the same month as acute URI was 4 (3-6). Only 519 (6.5 %) patients were claimed as acute URI alone. Regardless of the prescription of antibiotics, the most commonly redundantly claimed disease in these patients was allergic rhinitis, followed by acute bronchitis, acute sinusitis, and earwax impaction. The frequently prescribed antibiotics were third-generation cephalosporins, macrolides, and penicillins with extended-spectrum, including amoxicillin which was recommended by the Japanese manual; the proportion of patients with examinations was low (2.9-21.7 %). Among patients with acute URI, diagnoses requiring antibiotics were also claimed; therefore, when evaluating acute URI using the Japanese medical claims database, care must be taken in patient selection. Moreover, the implementation rate of examinations necessary for diagnosis was low, so there is an urgent need to develop an environment where examinations can be conducted in outpatient settings.

First reported isolation of hemin-requiring Proteus vulgaris small-colony variant from urine culture.

A hemin-requiring Proteus vulgaris small-colony variant (SCV) was isolated from a urine culture. This isolate was grown on 5% sheep blood agar but not on modified Drigalski agar. The single nucleotide substitution was found in the SCV of the hemC gene (c.55C > T), and this substitution caused a nonsense mutation (p.Gln19Ter). Porphyrin test results showed that the biosynthesis of δ-aminolevulinic acid stopped up to porphobilinogen and not pre-uroporphyrinogen due to a mutation in the hemC gene. To our knowledge, this is the first report of hemin-requiring P. vulgaris.

Nationwide surveillance of bacterial respiratory pathogens conducted by the surveillance committee of the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2019-2020: General view of the pathogens' antibacterial susceptibility.

The trends and prevalence of antimicrobial susceptibility of pathogens vary by country, region, and time. Long-term regular surveillance is required to investigate trends in the antimicrobial resistance of various isolated bacterial pathogens. We report the results of a nationwide surveillance on the antimicrobial susceptibility of bacterial respiratory pathogens in Japan conducted by the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology. The isolates were collected from clinical specimens obtained from adult patients who visited a collaborating medical facility between June 2019 and December 2020 and were diagnosed with respiratory tract infections by a physician. Antimicrobial susceptibility testing was performed in a centralized laboratory according to the methods recommended by the Clinical and Laboratory Standards Institute. Susceptibility testing was performed for 932 strains (201 Staphylococcus aureus, 158 Streptococcus pneumoniae, 6 S. pyogenes, 136 Haemophilus influenzae, 127 Moraxella catarrhalis, 141 Klebsiella pneumoniae, and 163 Pseudomonas aeruginosa) collected from 32 facilities in Japan. The proportions of methicillin-resistant S. aureus and penicillin-resistant S. pneumoniae were 35.3% and 0%, respectively. In H. influenzae, 16.2% and 16.9% were ß-lactamase-producing ampicillin resistant and ß-lactamase-negative ampicillin resistant, respectively. Extended-spectrum ß-lactamase-producing K. pneumoniae accounted for 5.0% of all K. pneumoniae infections. Carbapenemase-producing K. pneumoniae and multi-drug-resistant P. aeruginosa with metallo-ß-lactamase were not detected in this study. This surveillance will be a useful reference for treating respiratory infections in Japan and will provide evidence to enhance the appropriate use of antimicrobial agents.

[Evaluation of Methicillin Resistance Determination Time for MRSA Using Fully Automated Rapid Identification Susceptibility testing system RAISAS S4].

In this study, we examined the accuracy and rapidity of drug susceptibility determination using clinical isolates of MRSA with the fully automated rapid identification susceptibility testing system RAISUS S4. Ninety eight MRSA strains were used and the time until methicillin resistance was determined was analyzed by both of the standard method (18-hr method) and the rapid method. Five strains (5.1%) were determined to be methicillin-sensitive in MPIPC by rapid method only while all strains were determined to be resistant in CFX. The average methicillin resistance determination time was 7.0/5.0 hr for MPIPC, 6.3/5.0 hr for CFX, and 6.3/5.0 hr for the combination of MPIPC and CFX by the standard/rapid method, with the rapid method being significantly shorter (Wilcoxon's signed rank sum test, p<0.01). Strains determined to be methicillin-sensitive by MPIPC tended to have a longer time to methicillin resistance by the standard method, but this effect was much less pronounced for the rapid method using CFX. Methicillin resistance determination by the rapid method using RAISUS S4 enables rapid detection of MRSA without false-susceptible results, which may lead to early and appropriate treatment.

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 2016: General view of the pathogens' antibacterial susceptibility.

The nationwide surveillance on antimicrobial susceptibility of bacterial respiratory pathogens from the patients in Japan was conducted by the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2016. The isolates were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections during the period between February 2016 and August 2016 by three societies. Antimicrobial susceptibility testing was conducted at the central reference laboratory according to the method recommended by Clinical Laboratory Standards Institute. Susceptibility testing was evaluated in 1062 strains (143 Staphylococcus aureus, 210 Streptococcus pneumoniae, 17 Streptococcus pyogenes, 248 Haemophilus influenzae, 151 Moraxella catarrhalis, 134 Klebsiella pneumoniae, and 159 Pseudomonas aeruginosa). Ratio of methicillin-resistant S. aureus was 48.3%, and those of penicillin-susceptible S. pneumoniae was 99.5%. Among H. influenzae, 14.1% of them were found to be ß-lactamase-producing ampicillin-resistant strains, and 41.1% to be ß-lactamase-non-producing ampicillin-resistant strains. Extended spectrum ß-lactamase-producing K. pneumoniae and multi-drug resistant P. aeruginosa with metallo ß-lactamase were 4.5% and 0.6%, respectively.

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 2014: General view of the pathogens' antibacterial susceptibility.

The nationwide surveillance on antimicrobial susceptibility of bacterial respiratory pathogens from the patients in Japan was conducted by Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2014. The isolates were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections during the period between January 2014 and April 2015 by three societies. Antimicrobial susceptibility testing was conducted at the central reference laboratory according to the method recommended by Clinical Laboratory Standards Institute. Susceptibility testing was evaluated in 1534 strains (335 Staphylococcus aureus, 264 Streptococcus pneumoniae, 29 Streptococcus pyogenes, 281 Haemophilus influenzae, 164 Moraxella catarrhalis, 207 Klebsiella pneumoniae, and 254 Pseudomonas aeruginosa). Ratio of methicillin-resistant S. aureus was 43.6%, and those of penicillin-susceptible S. pneumoniae was 100%. Among H. influenzae, 8.2% of them were found to be ß-lactamase-producing ampicillin-resistant strains, and 49.1% to be ß-lactamase-non-producing ampicillin-resistant strains. Extended spectrum ß-lactamase-producing K. pneumoniae and multi-drug resistant P. aeruginosa with metallo ß-lactamase were 9.2% and 0.4%, respectively.

[Middle East Respiratory Syndrome (MERS)].

Middle East respiratory syndrome (MERS) is an emerging infectious disease of growing global importance, which has caused severe acute respiratory disease in more than 1,700 people, resulting in almost 600 deaths. MERS is caused by a novel betacoronavirus (MERS-CoV). All cases of MERS have been linked through travel to or residence in countries in or near the Arabian Peninsula. Dromedary camels are considered natu- ral reservoirs for MERS-CoV. MERS-CoV is mainly transmitted from infected dromedary camels to human beings, and it is transmitted among human beings by droplets, contact, and perhaps airborne spread. Both community-acquired and hospital-acquired cases have been reported with little human-to-human transmis- sion reported in the community. The largest known outbreak of MERS outside the Arabian Peninsula oc- curred in the Republic of Korea in 2015, with 186 cases. The outbreak was associated with a traveler re- turning from the Arabian Peninsula. Clinical features of MERS range from asymptomatic or mild disease to acute respiratory distress syndrome and multi-organ failure resulting in death, especially in individuals with underlying comorbidities. MERS is suspected in the presence of febrile acute respiratory illness and close contact with MERS-CoV, and can be confirmed by the detection of viral nucleic acid through RT-PCR or se- rology. No specific drug treatment exists for MERS; however, the neutralizing antibodies, ribavirin and interferon have been shown to be potentially useful anti-MERS-CoV drugs. Rigorous infection prevention and control measures with droplet and contact precautions are crucial to prevent the spread in health-care facilities. [Review].

Pneumocystis polymerase chain reaction and blood (1→3)-ß-D-glucan assays to predict survival with suspected Pneumocystis jirovecii pneumonia.

Pneumocystis polymerase chain reaction (PCR) and blood (1→3)-ß-D-glucan assays are known to be useful for the diagnosis of Pneumocystis pneumonia (PCP). However, their impact on the outcome of clinically suspected PCP patients has not yet been elucidated. Between January 2008 and July 2011, we prospectively observed 190 immunocompromised patients who had ground-glass opacity on chest computed tomography scans and were suspected to have PCP. The blood ß-D-glucan levels of these patients were measured, and PCR was used to detect Pneumocystis jirovecii in the respiratory samples. The 30-day mortality rates and related factors were assessed. The 30-day mortality rate of all included patients was 21.6%. Both ß-D-glucan-positive (10.1%) and PCR-positive patients (15.0%) had significantly lower mortality rates than ß-D-glucan-negative (28.1%) or PCR-negative patients (30.1%). All of the 13 definite PCP patients had positive PCR and ß-D-glucan results, received anti-PCP treatments, and survived. Among the 72 patients who were negative for microscopic detection of P. jirovecii but received anti-PCP treatments, positive PCR results (odds ratio [OR], 0.14; 95% confidence interval [CI], 0.02-0.74), a high Sequential Organ Failure Assessment score (OR, 1.42; CI, 1.08-1.88), and positive ß-D-glucan levels (OR 0.25, CI 0.06-1.02) were associated with mortality rates using stepwise logistic regression analyses. A positive Pneumocystis PCR or ß-D-glucan test was a candidate predictor of survival in patients who were suspected of having PCP, even though negative for visual detection by microscopy.

[Points of revision of the guideline JSLM 2012].

The revised version of the guideline JSLM 2012 was published in December 2012 by the Japanese Society of Laboratory Medicine. This version included new sections, such as blood gas analysis, sleep apnea syndrome, interstitial lung disease, liver and pancreas cancer, chronic kidney disease, acute kidney disease, gout and hyperuricemia, bone metabolism abnormality, malignant lymphoma, and rheumatoid arthritis. The guideline committee was composed of specialists in each field of internal medicine, who were responsible for selecting and requesting the authors and also in promoting and proofreading the manuscripts. In special program I at the 60th annual meeting, each specialist gave lectures concerning the points of the revision in their fields. The questionnaire surveys were performed using FAX or the Internet. Analysis of eighty-seven (2.5%) responses from 3,500 individuals/facilities, which were sent the guideline, revealed that this guideline was graded as excellent by 38 readers, fair by 42, and average by in 6. Significant opinions on the guideline were obtained from the readers, and they will be the bases for the next revision. The main subjects of this guideline were confirmed to be the residents and general physicians, by whom it is hoped the routine laboratory tests will be properly utilized. Therefore, based on the section of 'approach of the laboratory test results', which is a representative characteristic of this guideline, the sections of 'symptoms' will be fulfilled for the next version. This guideline needs to be periodically revised with advances in medicine.

MALDI-TOF MS identification of Exophiala species isolated in Japan: Library enrichment and faster sample preparation.

Exophiala species cause chromoblastomycosis, mycetoma, and phaeohyphomycosis, which are occasionally fatally in immunocompromised patients. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) provides rapid and accurate examination of isolated bacteria and some fungal isolates, but the preparation method for filamentous fungi is complicated. In this study, 31 clinical isolates of Exophiala spp. in Japan were identified by MALDI-TOF MS with a library enriched by adding data. To simplify the sample preparation method, two modified methods were compared with the standard method for filamentous fungi. The agar cultivation sample preparation method reduced the time required for liquid culture and was considered suitable for clinical use. In 30 of 31 clinical isolates of Exophiala spp., the species identified by MALDI-TOF MS with the highest score matched the species identified by sequencing the internal transcribed spacer region. Exophiala dermatitidis, E. lecanii-corni, and E. oligosperma were identified above the genus level, while E. jeanselmei and E. xenobiotica were often not identified at the species level. The identification scores tended to be lower for less-registered strains in the in-house library. It is suggested that library enrichment and the modified preparation method may facilitate early diagnosis of rare fungal infections by Exophiala spp. in clinical laboratories using MALDI-TOF MS.

[Enterococcus].

Enterococci have a variety of intrinsic antibiotic resistances, and also they can acquire new antibiotic resistance determinants including mutated ligase genes such as VanA or VanB. The increased prevalence and dissemination of multidrug-resistant Enterococci (i.e., Vancomycin resistant Enterococci: VRE) worldwide have resulted in a major decrease in therapeutic options and poor prognosis of infections by these organisms. Newer antibiotics, linezolid, Q/D, daptomycin and tigecycline have good in vitro activity against, however their clinical use are limited in certain infectious diseases. Although the prevalence of VRE in Japan is still quite low, strict infection control measures including active surveillance and regional information sharing is necessary to prevent dissemination in hospitals and regions.

Prognostic factors in patients with septic disseminated intravascular coagulation treated with thrombomodulin: the effect of reduced thrombomodulin dose; a single-center, retrospective, observational study.

BACKGROUND: Human soluble recombinant thrombomodulin (TM alfa), a treatment for septic Disseminated intravascular coagulation (DIC), is recommended for patients with severe renal dysfunction in reduced doses. However, no studies have examined yet how dose reduction affects clinical efficacy. In this study, we investigated the significance of the TM alfa dose as a prognostic factor in clarifying the clinical background factors related to the clinical effect of TM alfa in patients with septic DIC. METHODS: This study involved 102 patients with septic DIC admitted to a single-center intensive care unit between April 2013 and March 2020, receiving TM alfa. The following factors were retrospectively collected from the medical records of the target patients: (1) patient background, (2) sequential organ failure assessment (SOFA) score, (3) Japanese Association for Acute Medicine DIC diagnostic criteria score, (4) DIC treatment information, (5) TM alfa dose per bodyweight (normal dose: 0.06 mg/kg or reduced dose: 0.02 mg/kg), (6) DIC resolution within 7 days after the start of TM alfa administration (DIC resolution), (7) all deaths within 30 days after the start of TM alfa administration (30-days-all-cause mortality), (8) presence or absence of new hemorrhagic side effects after the start of TM alfa administration. Multiple logistic regression analysis was used to assess factors associated with DIC resolution and 30-days-all-cause mortality. RESULTS: The SOFA score (odds ratio: 95% confidence interval, 0.76: 0.66-0.89), pneumonia (0.24: 0.08-0.75), and reduced dose administration of TM alfa (0.23: 0.08-0.66) were independent of and negatively related to the DIC resolution. For the 30-days-all-cause mortality, the SOFA score (1.66: 1.31-2.09), pneumonia (9.50: 2.49-36.25), and TM alfa dose reduction (3.52: 1.06-11.69) were independent, poor prognostic factors. We found no association between the hemorrhagic side effects and the TM alfa dose per bodyweight. CONCLUSIONS: The reduced dose of TM alfa for patients with severe renal dysfunction was observed to be an influential factor for DIC resolution and 30-day all-cause mortality, as were SOFA scores and pneumonia. Further studies are required in the future to verify this finding.

Clinical and epidemiological features of healthcare workers after a coronavirus disease 2019 cluster infection in Japan and the effects of Kampo formulas-Hochuekkito and Kakkonto: A retrospective cohort study.

It is expected that a low-toxicity natural compound like Kampo formulas would exhibit a preventive effect on COVID-19, in a global outbreak of coronavirus disease 2019 (COVID-19). Although the biological properties and safety of the representative Kampo, Hochuekkito (HET), and Kakkonto (KKT) have been confirmed in various animal model experiments and clinical studies, and in a few human studies to induce biological effects on various infectious diseases without significant toxicity, it is unclear whether HET and KKT are safe and effective for COVID-19 prevention. We summarized the clinical characteristics of HCWs and the preventive effects of HET and KKT. We performed a retrospective, single-center, cohort study that included 175 HCWs (aged 21-77 years) from a total number of 217 in a hospital with a history of COVID-19 cluster infection. In total, 175 HCWs were tested for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) antibodies. We identified 27 patients (median age: 49 ± 10.7 years) who were diagnosed with COVID-19. The patients in the group that had a body mass index ≥ 25 had a high COVID-19 infection risk, while those in the group with a Kampo formula adherence rate ≥ 40% had a low COVID-19 risk. Patients in the group with an adherence rate ≥ 40%, as well as those in the current alcohol consumption group, were at a low risk of developing severe COVID-19. In conclusion, HET and KKT may have prevented the onset or worsening of COVID-19, which could be clinically used. Obesity might have increased the patients' susceptibility to COVID-19 and the disease severity.

Rapid response to a coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital-Kanazawa City, Japan, March to April 2020.

A coronavirus disease 2019 (COVID-19) outbreak in a psychiatry hospital revealed specific challenges in its response such as difficulty in isolation, transfer, and identification of close contacts, suboptimal infection control practices, and shortage of personal protective equipment, which were overcome by support from the public health center and a neighboring university hospital.

Antimicrobial ointments and methicillin-resistant Staphylococcus aureus USA300.

We tested 259 methicillin-resistant Staphylococcus aureus isolates and 2 USA300 ATCC type strains for susceptibility to bacitracin and neomycin contained in over-the-counter antibacterial ointments. Resistance to both bacitracin and neomycin was found only in USA300. The use of over-the counter antimicrobial drugs may select for the USA300 clone.

Clinical characteristics of Pneumocystis pneumonia in non-HIV patients and prognostic factors including microbiological genotypes.

BACKGROUND: The number of patients with non-HIV Pneumocystis pneumonia (PCP) is increasing with widespread immunosuppressive treatment. We investigated the clinical characteristics of non-HIV PCP and its association with microbiological genotypes. METHODS: Between January 2005 and March 2010, all patients in 2 university hospitals who had been diagnosed with PCP by PCR were enrolled in this study. Retrospective chart review of patients, microbiological genotypes, and association with 30-day mortality were examined. RESULTS: Of the 82 adult patients investigated, 50 patients (61%) had inflammatory diseases, 17 (21%) had solid malignancies, 12 (15%) had hematological malignancies, and 6 (7%) had received transplantations. All patients received immunosuppressive agents or antitumor chemotherapeutic drugs. Plasma (1→3) ß-D-glucan levels were elevated in 80% of patients, and were significantly reduced after treatment in both survivors and non-survivors. However, ß-D-glucan increased in 18% of survivors and was normal in only 33% after treatment. Concomitant invasive pulmonary aspergillosis was detected in 5 patients. Fifty-six respiratory samples were stored for genotyping. A dihydropteroate synthase mutation associated with trimethoprim-sulfamethoxazole resistance was found in only 1 of the 53 patients. The most prevalent genotype of mitochondrial large-subunit rRNA was genotype 1, followed by genotype 4. The most prevalent genotype of internal transcribed spacers of the nuclear rRNA operon was Eb, followed by Eg and Bi. Thirty-day mortality was 24%, in which logistic regression analysis revealed association with serum albumin and mechanical ventilation, but no association with genotypes. CONCLUSIONS: In non-HIV PCP, poorer general and respiratory conditions at diagnosis were independent predictors of mortality. ß-D-glucan may not be useful for monitoring the response to treatment, and genotypes were not associated with mortality.

Tocilizumab and PMX-DHP have efficacy for severe COVID-19 pneumonia.

In coronavirus disease 2019 pneumonia, a cytokine storm resulting from an excessive inflammatory response to the viral infection is thought to play a role in the exacerbation of the pneumonia and its prognosis. Favipiravir and ciclesonide are not effective in the inhibition of the cytokine storm. In this case report, we describe the experience of tocilizumab administration and polymyxin B immobilized fiber direct hemoperfusion in severe coronavirus disease 2019 pneumonia patient. A 52-year-old man presented with fever and dyspnea and was diagnosed with coronavirus disease 2019 pneumonia based on a polymerase chain reaction test. Mechanical ventilation and favipiravir administration were started for respiratory failure. However, favipiravir could not be continued due to hepatic dysfunction. Consequently, tocilizumab was administered, and continuous hemodiafiltration and endotoxin adsorption therapy (polymyxin B immobilized fiber direct hemoperfusion) were performed for acute renal failure. C-reactive protein decreased from 44 to 3.52 mg/dL, and the patient's respiratory status improved over time, enabling mechanical ventilation to be withdrawn. This case indicates that adding polymyxin B immobilized fiber direct hemoperfusion to tocilizumab administration may further increase efficacy in coronavirus disease 2019 treatment; however, more case-control studies are needed.

[Rapid-tests detection evaluation of Clostridium difficile toxins and microbiological investigation].

We evaluated two rapid toxin tests for C. difficile combined with stool specimen cultures used from January 2006 to March 2009. Stool specimens numbered 877, 102 among which were from the cases of diagnosed clinical C. difficile-associated diarrhea (CDAD). Rapid toxin A 'Uniquick' detection kits were used until October 2007 and toxin A&B 'TOX A/B' detection kits thereafter. Clinical CDAD was considered the detection gold standard. Uniquick sensitivity, specificity, and positive and negative predictive values were 54.3%, 99.1%, 90.5%, and 93.2% while those for TOX A/B were 46.2%, 97.6%, 65.2%, and 95.0% and for culture 42.2%, 95.5%, 55.1%, and 92.6%. Rapid toxin tests tended to have better sensitivity than culture results although not significantly so, and Uniquick showed significantly better positive predictive value than TOX A/B or culture results. Among clinical CDAD cases, concordance with culture was 24.3% for Uniquick and 53.1% for TOX A/B. For stored strains, 27 were typed toxin A+B+ (48.1%), toxin A-B+ (37.0%) and toxin A-B- (14.8%) with toxin gene detection by PCR. Eight of the 10 toxin A-B+ strains were classified into two cluster by ribotyping, and 7 of those were detected in two hospital wards, indicated the possibility of nosocomial toxin A-B+ strain spread. The rapid toxin test for both toxins A and B should be used if toxin A-B+ predominate. Simultaneous culture testing may be useful for detecting clinical CDAD more accurately, however.

Evaluation of Antibacterial and Cytotoxic Properties of a Fluorinated Diamond-Like Carbon Coating for the Development of Antibacterial Medical Implants.

Peri-implant infection is a serious complication in surgical procedures involving implants. We conducted an in vitro study to determine whether the use of a fluorinated diamond-like carbon (F-DLC) coating on a titanium alloy surface can prevent peri-implant infection. After applying the F-DLC, we evaluated its antibacterial and cytotoxic properties. The coating groups, containing controlled fluorine concentrations of 5.44%, 17.43%, 24.09%, and 30%, were examined for the presence of Staphylococcus aureus and Escherichia coli according to ISO 22196 for the measurement of antibacterial activity on plastics and other nonporous surfaces. Biological toxicity was evaluated using Chinese hamster V79 cells according to ISO 10993-5 for the biological evaluation of medical devices. In the control group, populations of S. aureus and E. coli substantially increased from 2.4 × 104 to (1.45 ± 1.11) × 106 colony-forming units (CFUs) and from 2.54 × 104 to (4.04 ± 0.44) × 106 CFUs, respectively. However, no bacteria colonies were detected in any F-DLC group with a fluorine concentration of ≥ 17.43%. In the biological toxicity study, an F-DLC coating with a fluorine concentration of 30% showed a colony formation rate of 105.8 ± 24.1%, which did not differ significantly from the colony formation rate of 107.5 ± 31.1% in the nontoxic control group. An F-DLC coating on titanium alloy discs showed excellent in vitro antibacterial activity with no biological toxicity.