Identification and antifungal sensitivity of two new species of Diaporthe isolated.

Diaporhte species are plant pathogens rarely involved in human diseases, especially eye diseases. We report our findings in two undescribed Diaporhte species. Both were identified by their morphological characteristics and by DNA sequence analyses. In Case 1, an 81-year-old male farmer who had pterygium surgery 7 years earlier developed keratitis and the causal fungus was identified as a new species of Diaporthe, D. oculi. This species can be distinguished from the closely related D. limonicola on Citrus limon (Rutaceae) by the ITS, tef1, and TUB (515/520 = 99.0% in ITS, 315/324 = 97.2% in tef1, and 601/614 = 97.9% in TUB). The isolate from Case 2, a 68-year-old man with a rose thorn injury, was also identified as a new Diaporthe species, D. pseudooculi. Phylogenetically, D. pseudooculi is different from the closely related D. podocarpi-macrophylli by the ITS, tef1, and TUB (525/531 = 98.9% in ITS, 314/333 = 94.3% in tef1, and 436/442 = 98.6% in TUB). We report on the identification, drug sensitivity, and treatment outcomes for these two new species of Diaporthe, D. oculi and D. pseudooculi.

Clinical impact of extended blood culture examination: Too much of a good thing.

Blood culture is the most critical examination for diagnosing bacterial infections. The longer the blood culture incubation period, the higher the chances of identifying bacterial strains. However, unnecessary extension of the incubation period can burden the capacity of the instrument and merely result in the detection of contaminant bacteria having no clinical significance. This study aimed to optimize the blood culture incubation period using the currently available continuous-monitoring automated blood culture instrument. This was a 2-year retrospective study performed at Osaka University Hospital (January 1, 2016 to December 31, 2017). The BD BACTEC™ FX blood culture system (Becton Dickinson, Sparks, MD, USA) and BD BACTEC™ Plus series blood culture bottles were used. All blood cultures were incubated for more than 12 consecutive days. We reviewed the clinical data of cases that tested positive between 6 and 12 days of incubation. During the study period, 14,822 sets of blood culture were drawn. Of 1751 sets testing positive, 95.7% (1665 sets) became positive within 5 days of incubation. The overall contamination rate (false positives) after 6 days of incubation was 80.2% (69/86 sets). Based on the positive blood culture results, antimicrobials were changed in 7.0% (6/86) of the sets, and a diagnosis of infectious disease was made in only one case. There was no death associated with the extended blood culture results. In conclusion, the clinical impact of extended blood culture incubation for 6 days or more was limited, and a routine extension of the incubation period might be unnecessary.

A fatal case of Exophiala dermatitidis disseminated infection in an allogenic hematopoietic stem cell transplant recipient during micafungin therapy.

Exophiala dermatitidis is a dematiaceous fungus that is increasingly becoming the cause of fungal infection in immunocompromised patients. However, the risk factors and optimal treatment modality for E. dermatitidis infection are unknown to date. Herein, we present a fatal case of E. dermatitidis infection in an adult patient that developed after allogeneic hematopoietic stem cell transplantation for chronic active Epstein-Barr virus infection. The dematiaceous fungus caused a breakthrough fungemia despite prophylactic administration of micafungin. Although the patient was intensively treated with liposomal-amphotericin B and voriconazole, serum level of beta-D-glucan continuously increased, and the patient eventually died because of cerebral hemorrhage. An autopsy found multiple involvements of the fungal infection at the bilateral lungs, thoracic cavities, diaphragm, and thyroid. To the best of our knowledge, this is the first reported case of E. dermatitidis infection involving these tissues as determined via autopsy. This case highlights the importance of attention for Exophiala infection in immunocompromised individuals in those given antifungal therapy with echinocandins.

Roussoella solani causing keratomycosis, with an observed both sexual and asexual morphs.

We describe an 82-year-old male farmer who had diabetes mellitus with no history of ocular trauma by soil or plants and who developed a corneal infection due to a fungus. The organism was identified as Roussoella solani based on both the morphological characteristics and phylogenetic analysis using LSU and ITS nrDNA sequences. The sexual stage of R. solani is described and illustrated for the first time. The patient was treated successfully with a combination of topical and systemic voriconazole and micafungin. This case is the first report of keratomycosis caused by R. solani.

[Multicenter Prospective Observational Study of Fungal Keratitis--Identification and Susceptibility Test of Fungi].

PURPOSE: To investigate the causative fungi of fungal keratitis in Japan and their drug susceptibility. METHODS: Identification and antifungal susceptibility test for 8 drugs (micafungin, amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole, miconazole and pimaricin) were performed using isolated fungi from patients with fungal keratitis treated at 27 facilities in Japan between November 1, 2011 and October 31, 2013. RESULTS: Fungal strains were detected in 72 (50.7%) out of 142 samples. The major isolates were Fusarium spp. (18), Candida parapsilosis (12), C. albicans (11) and Alternaria spp. (6), in all, fungi of 31 species were identified by gene analysis. In the yeast-like fungi, susceptibility rates were evident for more than 80% in voriconazole, pimaricin, flucytosine, micafungin, amphotericin B and fluconazole. In filamentous fungi, the susceptibility rate was less than 50% except for PMR (90%). Fusarium spp., which were susceptible to amphotericin B and pimaricin, showed lower susceptibility rates compared with other genera. CONCLUSIONS: Although various genera and species of fungi cause fungal keratitis, the obtained drug susceptibility data in this study demonstrates the different susceptibility patterns among the major isolates (Fusarium spp., C. parapsilosis, C. albicans and other groups). This is important evidence useful for fungal keratitis treatment.

[Multicenter Prospective Observational Study of Fungal Keratitis--Current Status of Patients' Background, Clinical Findings, Treatment and Prognosis].

PURPOSE: To investigate the current status of fungal keratitis in Japan. METHODS: The patients with fungal keratitis were examined at 27 facilities in Japan from November 1st 2011 to October 31st 2013, concerning isolates, patient background, clinical findings, treatment and prognosis. RESULTS: Out of 139 cases, 133 were diagnosed as fungal keratitis, of which fungi were isolated from 72 samples of 71 cases (yeast-like fungi 32 strains and filamentous fungi 40 strains). The corrected visual acuity at the first visit of 88 cases (66.2%) was less than 20/200 and 42 cases (31.6%) were involved with deep stromal lesions, indicating high proportion of severe cases in this study. Three months later, 56 cases (42.1%) were still under treatment, and corrected visual acuity of 57 cases (42.9%) was less than 20/200. In cases with yeast-like fungi, there were significantly more cases with past history of corneal diseases, ocular surgery including keratoplasty, and eye drops' use such as steroids than those with filamentous fungi. On the other hand, there were significantly more cases of filamentous fungi, with trauma on the onset and with intervention of previously attending doctors than those with yeast-like fungi. Logistic regression analyses revealed that contact lens wearing was a significant factor of good prognosis, and yeast-like fungi as one of poor outcome compared with no fungal isolation. CONCLUSION: Although the choice of antifungal drugs has been increasing, fungal keratitis is still severe, refractory and vision-threatening disease.

In vitro evaluations of topical agents to treat Acanthamoeba keratitis.

PURPOSE: To evaluate the effectiveness of topical agents for the treatment of Acanthamoeba keratitis (AK). DESIGN: Laboratory research. PARTICIPANTS: Fifty-six Acanthamoeba isolates from 56 patients with clinically proven AK were studied. METHODS: The effectiveness of 7 agents against Acanthamoeba cysts was determined in vitro. The agents were 1.0% povidone-iodine, 0.05% benzalkonium chloride (BZC), 0.02% chlorhexidine gluconate (CHG), 0.1% propamidine isethionate, 0.02% polyhexamethylene biguanide (PHMB), 5.0% natamycin, and 1.0% voriconazole (VRCZ). These concentrations are those recommended for patients. In addition, 10-fold dilutions of each of the agents were tested. After exposing the cysts to each agent at 35°C for 1 hour or 24 hours, the agents were removed by centrifugal washing. The exposed cysts were observed by optical microscopy for 7 days. In addition, the fine structures of the exposed isolates were examined by transmission electron microscopy (TEM). The genotype of the isolates was determined by 18S rDNA fragment sequencing. MAIN OUTCOME MEASURES: The in vitro susceptibility was determined by complete growth inhibition, and the morphologic appearance was determined by TEM. The genotypes of the 56 isolates were determined by 18S rDNA fragment sequencing. RESULTS: The Acanthamoeba cysts were most susceptible to natamycin, followed by povidone-iodine, BZC, PHMB, propamidine, and CHG. None of the strains was susceptible to VRCZ. The susceptibilities to PHMB and CHG may be time dependent and to propamidine may be concentration dependent. Transmission electron microscopy showed changes in the inner structure of the cysts exposed to natamycin and povidone-iodine. The Acanthamoeba genotype was T4 in 52 isolates, and cysts with the same genotype had different agent susceptibilities. CONCLUSIONS: Natamycin and povidone-iodine had excellent cysti-static (or cystcidal) effects, and PHMB and propamidine did not. There was no correlation between agent effectiveness and Acanthamoeba genotype. Therefore, susceptibility tests of isolates are needed to choose the most appropriate agent, and our results can be a guideline for choosing the most appropriate agent for immediate empirical treatment of AK.

Reliable and reproducible method for rapid identification of Nocardia species by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been challenged for the identification of Nocardia species. However, the standard ethanol-formic acid extraction alone is insufficient in allowing the membrane proteins of Nocardia species to be ionized by the matrix. We therefore aimed to establish our new extraction method for the MALDI-TOF MS-based identification of Nocardia species isolates. Our modified extraction procedure is through dissociation in 0.5% Tween-20 followed by bacterial heat-inactivation, mechanical breaking of the cell wall by acid-washed glass beads and protein extraction with formic acid and acetonitrile. As reference methods for species identification, full-length 16S rRNA gene sequencing and some phenotypical tests were used. In a first step, we made our own Nocardia database by analyzing 13 strains (13 different species including N. elegans, N. otitidiscaviarum, N. asiatica, N. abscessus, N. brasiliensis, N. thailandica, N. farcinica, N. nova, N. mikamii, N. cyriacigeorgica, N. asteroids, Nocardiopsis alba, and Micromonospora sp.) and registered to the MALDI BioTyper database. Then we established our database. The analysis of 12 challenge strains using the our database gave a 100% correct identification, including 8 strains identified to the species level and 4 strains to the genus level (N. elegans, N. nova, N. farcinica, Micromonospora sp.) according to the manufacture's log score specifications. In the estimation of reproducibility of our method intended for 4 strains, both within-run and between-run reproducibility were excellent. These data indicates that our method for rapid identification of Nocardia species is with reliability, reproducibility and cost effective.

Multicenter prospective observational study of fungal keratitis in Japan: analyses of culture-positive cases.

PURPOSE: To investigate the clinical characteristics and causative fungi in patients with fungal keratitis in Japan, and to determine factors related to the prognosis. STUDY DESIGN: Multicenter prospective observational study. METHODS: Eligible patients were enrolled from November 2011 to October 2013 at the 1st stage and from April 2015 to March 2016 at the 2nd stage. The corneal foci were scraped, and the scrapings were cultured in potato dextrose agar. The isolated fungi were identified by gene analyses. Data were collected from the clinical records and statistically analyzed by Cox and logistic regression analyses. RESULTS: Ninety-four fungal strains were isolated from 93 cases, including 42 yeast-like fungi and 52 filamentous fungi. The fungi affected the deep layers of the cornea in 23 cases (24.7%) and the peripheral cornea in 29 cases (31.2%). The incidences of lid swelling/redness, ciliary injection, anterior chamber cells/flare, anterior chamber fibrin, and hyphate ulcer in cases of filamentous fungi were significantly higher than in yeast-like fungi. No history of topical steroids, absence of a main lesion in the peripheral cornea, and best-corrected visual acuity (BCVA) of more than 0.04 at the first visit were related to a shorter healing time. No history of ocular surgery, absence of lesion at one-third deep stromal layer and BCVA of more than 0.04 at the first visit were correlated with BCVA at 3 months after the initial examination. CONCLUSION: Fungal keratitis is caused by various species of fungi and can become refractory due to poor prognosis factors.

Multicenter prospective observational study of fungal keratitis in Japan: analyses of in vitro susceptibility tests for combinations of drugs.

PURPOSE: To determine the effects of a combination of two antifungal drugs against causative fungi of fungal keratitis in Japan. STUDY DESIGN: Multicenter prospective observational study. METHODS: Eighteen isolates of yeast-like fungi and 22 isolates of filamentous fungi collected by the Multicenter Prospective Observational Study of Fungal Keratitis in Japan were studied. Specially manufactured minimum inhibitory concentration (MIC) measurement plates were used to test the effectiveness of 10 combinations of two antifungal drugs against the isolates. The combinations were pimaricin (PMR) + voriconazole (VRCZ), PMR + fluconazole (FLCZ), PMR + miconazole (MCZ), PMR + micafungin (MCFG), VRCZ + FLCZ, VRCZ + MCZ, VRCZ + MCFG, VRCZ + amphotericin-B (AMPH-B), MCZ + FLCZ, and MCZ + MCFG. The checkerboard microdilution method was used, and the fractional inhibitory concentration (FIC) index was calculated based on the guidelines of The Clinical & Laboratory Standards Institute (CLSI). RESULTS: In yeast-like fungi, additive effects were observed between PMR and MCFG in 77.8% of the isolates, and they were also observed between the azoles. Synergistic effects were observed on 11.1% of the isolates for MCZ and FLCZ. On the other hand, antagonistic effects were present between PMR and azoles with 88.9% between PMR and VRCZ, 72.2% between PMR and FLCZ, and 94.4% between PMR and MCZ. In filamentous fungi, additive effects were observed between PMR and MCFG in 40.9% of the isolates, and between VRCZ and MCZ in 40.9% of the isolates. Antagonistic effects were observed for PMR and the azoles. CONCLUSIONS: The combination of drugs prescribed for fungal keratitis incurs a possibility of synergistic, additive, indifferent, or antagonistic effects, depending on drug combinations and fungal strains.

Successful medical management of Pythium insidiosum keratitis using a combination of minocycline, linezolid, and chloramphenicol.

PURPOSE: To report successful medical management of Pythium insidiosum keratitis using an antibiotic combination of minocycline, linezolid, and chloramphenicol. OBSERVATIONS: A 20-year-old Japanese man was referred for visual disturbance, hyperemia, and discharge from his right eye. Slit-lamp examination revealed a paracentral corneal hyphate ulcer. His visual acuity was 20/28. Smear examination of corneal scrapings revealed a filamentous fungus. Pimaricin ointment four times a day and voriconazole eye drops hourly were initially prescribed. Although intravenous liposomal amphotericin B 100 mg was added, the corneal infiltrates and ulcer worsened. The possibility of P. insidiosum keratitis was considered, and in vitro antifungal susceptibility testing were performed based on the disc diffusion method. The inhibition zones around each antibiotic disc revealed that the pathogen was susceptible to minocycline, linezolid, and chloramphenicol. Therefore, minocycline ointment four times a day, chloramphenicol eye drops hourly, and linezolid 1200 mg orally per day were also administered. Eventually, sequencing of ribosomal DNA confirmed the pathogen to be P. insidiosum. The triple regimen dramatically improved the patient's keratitis. Therapeutic penetrating keratoplasty for corneal perforation was successfully performed, and his visual acuity recovered from 20/2000 to 20/25. CONCLUSIONS AND IMPORTANCE: We have encountered a case of P. insidiosum keratitis that responded to a combination of minocycline, linezolid, and chloramphenicol. This triple combination should be considered in patients with P. insidiosum keratitis.

[Comparison of minimum inhibitory concentration and postantibiotic effect of eyedrops on isolates in National Surveillance of Infectious Keratitis in Japan].

PURPOSE: To determine the minimum inhibitory concentration (MIC) and postantibiotic effect (PAE) of antibiotic eyedrops against various isolates from infectious keratitis samples. METHOD: MIC and postantibiotic bactericidal effect (PABE)/postantibiotic fungicidal effect (PAFE) after 4 min of exposure to nine antibacterial eyedrops or four antifungals were examined using 100 clinical isolates collected by the National Surveillance of Infectious Keratitis in Japan in 2003. RESULT: The PABEs of tobramycin and micronomicin sulfate showed better results than other drugs, and the other drugs demonstrated various PABEs depending on the bacterial strains; in particular most drugs showed low PABE against Serratia marcescens. There were no significant differences between PABEs of methicillin-resistant and methicillin-susceptible Staphylococci. Also there was no statistical correlation between MIC and PABE of Staphylococci. All the antifungals demonstrated low PAFE against Candida spp. CONCLUSION: PABE/PAFEs vary among species of microorganisms, and since they have no relation with the usual MIC, various other factors, including species of isolates, actual clinical effects, and prevention of drug-resistance induction, should be considered in the selection of drugs.

[Report of questionnaire survey for methicillin-resistant Staphylococcus aureus and penisillin-resistant Streptococcus pneumoniae between 1998 and 2000 in the Kinki district].

Kinki Infection Working Group made an annual (1998-2000) comparative study of an epidemiological investigation for Staphylococcus aureus and Streptococcus pneumoniae in the Kinki district. The number of S. aureus and methicillin-resistant S. aureus (MRSA) isolated decreased for three years, but the isolation frequencies of MRSA has not changed which was approximately 60%. All strains of MRSA were not resistant to vancomysin (VCM) and teicoplanin (TEIC), and the frequencies of resistance to sulfamethoxazole-trimethoprim (ST) and arbekacin (ABK) were 0.1 to 0.7% and 1.9 to 3.1%, respectively. On the other hand, the number of S. aureus and penicillin-resistant S. pneumoniae (PRSP) isolated did not show a consistent tendency, but the isolation frequencies of PRSP has increased for three years. All strains of PRSP were sensitive to vancomycin (VCM), but the frequencies of resistance to cefaclor and other some antibiotics have increased.

Fungal keratitis caused by Beauveria bassiana: drug and temperature sensitivity profiles: a case report.

BACKGROUND: Beauveria bassiana is an entomopathogenic fungus and is a rare cause of keratitis. We present a case of fungal keratitis caused by B. bassiana that was diagnosed by in vivo confocal microscopy and in vitro corneal cultures. In addition, we determined the temperature- and drug-sensitivities of the isolated strain of B. bassiana. CASE PRESENTATION: A 59-year-old Japanese man with a 2-month history of keratitis was examined by slit-lamp biomicroscopy, in vivo confocal microscopy, and histology and cultures of corneal scrapings. The corneal scrapings were used to determine the minimal inhibitory concentrations of different antifungal drugs and also to determine the temperature-sensitivity. In vivo confocal microscopy and histological examinations showed filamentous fungal keratitis. The characteristics of the fungal growth indicated that the keratitis was caused by B. bassiana. The keratitis responded poorly to systemic and topical voriconazole and to natamycin ointment. However, it was resolved after changing the natamycin to micafungin combined with surgical debridement. The isolated strain was sensitive to itraconazole, miconazole, micafungin, voriconazole, and resistant to flucytosine and fluconazole. It was moderately sensitive to amphotericin B, and natamycin. After 7 days in culture, the isolate grew small white colonies at 25 °C, very small colonies at 35 °C and 37 °C. CONCLUSION: The drug-sensitivity and temperature-sensitivity profiles of B. bassiana should be helpful in the treatment of B. bassiana keratitis. Therapeutic surgery may be helpful for mycotic keratitis poorly responsive to medical therapy alone.

First case of fungal keratitis caused by Pestalotiopsis clavispora.

PURPOSE: To report the isolation of Pestalotiopsis clavispora from the cornea of a patient with recurrent keratitis. CASE REPORT: A 73-year-old male gardener presented with conjunctival injection and an oval infiltrate with feathery margins in the temporal half of the cornea in the right eye. His ocular history in the right eye included cataract surgery, five episodes of herpes simplex keratitis, three glaucoma surgeries, and bullous keratopathy. He had been treated with corticosteroids for years. Light microscopy of corneal scrapings revealed a filamentous fungus, and fungal keratitis was diagnosed. Treatment with topical voriconazole and pimaricin ointment was commenced. One month later, the infiltrate resolved. The antifungal agents were discontinued 7 months later, and keratitis relapsed 4 days after the discontinuation. The fungus was isolated and identified by molecular techniques as P. clavispora. Based on the results of antifungal susceptibility testing, treatment with topical and intravenous micafungin was initiated. The corneal infiltrate resolved 1 month after the relapse. CONCLUSION: Molecular identification of the pathogen, and antifungal susceptibility testing, are useful in treating patients with fungal keratitis caused by a rare human pathogen.

Clinical characteristics of keratitis due to Colletotrichum gloeosporioides.

PURPOSE: To determine the characteristics of the keratitis due to Colletotrichum gloeosporioides. METHODS: The medical records of 3 cases of fungal keratitis caused by C. gloeosporioides were reviewed to determine the clinical characteristics. The minimal inhibitory concentrations of different antifungal drugs for all 3 isolates were determined. All 3 isolates were grown on Sabouraud dextrose agar at 25°C, 35°C, and 37°C to determine the temperature-sensitive growth. RESULTS: All 3 patients lived in the southwestern part of Japan and had an ocular trauma involving organic materials. The infectious foci were localized in the anterior stroma, and they did not extend deep into the stroma in all cases. The keratitis was treated with antifungal medications including topical voriconazole and natamycin eye ointment, and was resolved in 2-3 weeks. All of the isolated strains grew well at 25°C but poorly at 35°C and 37°C. All isolated strains had similar drug-sensitivity profiles; they were sensitive to amphotericin B, itraconazole, miconazole, micafungin, and voriconazole, and relatively resistant to flucytosine, fluconazole, and natamycin. CONCLUSIONS: All 3 cases of C. gloeosporioides keratitis had similar clinical features. The similarities in the drug-sensitivity profiles should be helpful in treating C. gloeosporioides keratitis.

In vitro antifungal combination effects of micafungin with fluconazole, voriconazole, amphotericin B, and flucytosine against clinical isolates of Candida species.

Micafungin (MCFG) is an echinocandin antifungal agent that exhibits potent activity against most species of Candida and Aspergillus. We investigated the in vitro antifungal combination effects of MCFG with four other antifungal agents - fluconazole (FLCZ), voriconazole (VRCZ), amphotericin B, and flucytosine - against clinical isolates of 54 Candida spp. by checkerboard analysis. The synergistic antifungal effects of MCFG-FLCZ and MCFG-VRCZ were 11% and 15%, respectively, and the latter displayed a synergistic activity of 63% against Candida glabrata. Antagonism was not observed in any of the combinations tested.

The characteristics of keratomycosis by Beauveria bassiana and its successful treatment with antimycotic agents.

Clinical findings and treatment of keratomycosis caused by Beauveria bassiana, an entomopathogenic filamentous fungus, are described for an 80-year-old woman, who was referred to the hospital for ocular pain and redness on the 9th day after an ocular injury caused by the frame of her glasses. She had a long history of recurrent diabetic iritis and continuously used topical antibiotics and corticosteroids. At her first visit, a slit-lamp examination indicated a corneal ulcer confined within the superficial stromal layer, along with a slight infiltration and edema. Only a very few inflammatory cells were seen in the anterior chamber. Direct microscopic examination of corneal scrapings revealed septate fungal hyphae with zig-zag rachis and budding that was subsequently identified as B. bassiana by slide culture. Topical voriconazole with miconazole, pimaricin and oral itraconazole were effective and the lesion disappeared leaving only a mild scar at 2 months. The sensitivity of B. bassiana to various antimycotic agents was confirmed by broth microdilution, agar dilution with the Clinical Laboratory Standard Institute standard, and a disk method using topically applied concentrations. B. bassiana, which exhibits a characteristic appearance in smears and causes superficial keratomycosis, is sensitive to voriconazole with miconazole, pimaricin, and itraconazole.

Pseudomembranous colitis caused by toxin A-negative/toxin B-positive variant strain of Clostridium difficile.

We report the first case of pseudomembranous colitis (PMC) due to a toxin A-negative, toxin B-positive strain (toxin A variant strain) of Clostridium difficile in Japan. The toxin A variant strain of C. difficile is capable of causing PMC and is undetectable in clinical laboratories that use only toxin A immunoassays for C. difficile testing. If C. difficile-associated diarrhea is clinically suspected and toxin A is not detected, then the possibility of a toxin A variant strain should be considered, and further diagnostic testing, such as polymerase chain reaction (PCR) analysis for the detection of C. difficile toxin genes should be performed.