Aneurysm Infection Caused by Desulfovibrio desulfuricans.

An 84-year-old man in Japan who had undergone endovascular aortic repair 9 years earlier had an infected aneurysm develop. We detected Desulfovibrio desulfuricans MB at the site. The patient recovered after surgical debridement, artificial vessel replacement, and appropriate antimicrobial therapy. Clinicians should suspect Desulfovibrio spp. infection in similar cases.

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.

Comparison of the performance of three carbapenem inactivation methods for the detection of carbapenemase-producing gram-negative bacilli.

INTRODUCTION: The carbapenem inactivation method test (CIM) was developed as a method for detecting carbapenemase-producing Gram-negative bacilli, and the modified CIM (mCIM) was recommended by the CLSI for as an improved method in M100-S27. However, few studies have evaluated the influence of bacterial species and genotype on its sensitivity and specificity. In this study, we evaluate the performance of these improved modified CIM methods with mCIM. METHODS: As strains, clinical isolates from Naga Municipal Hospital and stored strains from the Study of Bacterial Resistance in the Kinki Region of Japan were used. The mCIM, CIM-Tris, and simple CIM (sCIM) test methods were applied to 120 Enterobacterales, 40 Pseudomonas aeruginosa, and 37 Acinetobacter spp. The procedure and criteria for each method were based on the original papers and the CLSI M - 100 S27 documents. RESULTS: The sensitivity of the test methods in the detection of carbapenemase in Enterobacterales, Pseudomonas spp., and Acinetobacter spp. was as follows: mCIM, 98.9%, 90.0%, and 76.5%, respectively; CIM-Tris, 94.4%, 100%, 100%; and sCIM 98.9%, 85.0%, 76.5%. All methods showed 100% specificity in Enterobacterales, Pseudomonas spp., and Acinetobacter spp. Each method performed well in the detection of metallo ß-lactamase-producing strains, however, the sensitivity tended to be low in the detection of the organisms producing serine-type carbapenemase, such as GES, OXA-23, and OXA-51. CONCLUSIONS: Care must be taken when selecting test methods because the sensitivity of the detection differs depending on the bacterial species and genotype.

Evaluation of five Legionella urinary antigen detection kits including new Ribotest Legionella for simultaneous detection of ribosomal protein L7/L12.

Urinary antigen tests are a widely used rapid diagnostic method for Legionella pneumonia. However, conventional urinary antigen tests are unable to detect anything other than Legionella pneumophila serogroup 1. The Ribotest Legionella (Ribotest) can detect all serogroups by using antibodies recognizing L. pneumophila ribosomal protein L7/L12 in addition to the conventional L. pneumophila serogroup 1 lipopolysaccharide. The aim of this study was to evaluate the performance of Ribotest against conventional urinary antigen tests, including the detection of Legionellaceae other than L. pneumophila. We investigated the detection sensitivity of various kits using in-vitro culture-soluble antigen extracts of ATCC strains and 22 clinical isolates collected from multiple medical facilities in the Kinki region of Japan. For L. pneumophila serogroup 1, four kits, including Ribotest, had a detection sensitivity of 105 CFU/mL, with only Check Legionella having a sensitivity of 106 CFU/mL. L. pneumophila non-serogroup 1 and Legionellaceae of other species were undetectable by the four conventional kits, whereas Ribotest could detect them with a sensitivity of 105-108 CFU/mL. The Ribotest was also able to detect other species such as Legionella hackeliae, Legionella feeleii, Legionella anisa, Fluoribacter bozemanae, and Fluoribacter dumoffii, but the detection sensitivity of L. hackeliae and L. feeleii was 108 CFU/mL, which was much lower than that of the other strains. The Ribotest has high potential to be applied as a rapid diagnostic method for pneumonia caused by other species of Legionella and Fluoribacter.

Disseminated gonococcal infection in a Japanese man with complement 7 deficiency with compound heterozygous variants: A case report.

RATIONALE: Complement deficiency are known to be predisposed to disseminated gonococcal infection (DGI). We herein present a case of DGI involving a Japanese man who latently had a complement 7 deficiency with compound heterozygous variants. PATIENT CONCERNS: A previously healthy 51-year-old Japanese man complained of sudden-onset high fever. Physical examination revealed various skin lesions including red papules on his trunk and extremities, an impetigo-like pustule on left forearm, and tendinitis of his right forefinger. DIAGNOSIS: Blood culture testing detected gram-negative cocci, which was confirmed to be Neisseria gonorrhoeae based on mass spectrometry and a pathogen-specific PCR test. INTERVENTIONS: Screening tests for underlying immunocompromised factors uncovered that complement activities (CH50) was undetectable. With a suspicion of a congenital complement deficiency, genetic analysis revealed rare single nucleotide variants in complement 7 (C7), including c.281-1G>T and a novel variant c.1454C>T (p.A485V). CH50 was normally recovered by adding purified human C7 to the patient's serum, supporting that the patient has C7 deficiency with compound heterozygous variants. OUTCOMES: Under a diagnosis of DGI, the patient underwent an antibiotic treatment with cefotaxime for a week and was discharged without any sequela. LESSONS: DGI is a rare sexually-transmitted infection that potentially induces systemic complications. Complement immunity usually defeats N. gonorrhoeae and prevents the organism from causing DGI. This case highlighted the importance of suspecting a complement deficiency when a person develops DGI.

Antimicrobial susceptibility surveillance of obligate anaerobic bacteria in the Kinki area.

Obligate anaerobes exist as resident flora in various sites in humans, but they are also emphasized as endogenous causative microorganism of infections. We performed surveillance to understand the trend of drug susceptibility in obligate anaerobic bacteria in the Kinki area of Japan. In the experiment, we used 156 obligate anaerobe isolates collected from 13 institutions that participated in the Study of Bacterial Resistance Kinki Region of Japan. MALDI Biotyper was used to identify the collected strains, and among the 156 test strains, those that could be identified with an accuracy of Score Value 2.0 or more included 6 genera, 30 species, and 144 strains (Bacteroides spp. 77 strains, Parabacteroides sp. 2 strains, Prevotella spp. 29 strains, Fusobacterium spp. 14 strains, Porphyromonas spp. 2 strains, and Clostridioides difficile 20 strains), and they were assigned as subject strains for drug susceptibility testing. The drug susceptibility test was carried out by broth microdilution method using Kyokuto Opt Panel MP ANA (Kyokuto Pharmaceutical Industrial Co., Ltd., Tokyo, Japan) and judged according to CLSI criteria. As a result, Bacteroides and Parabacteroides species showed good sensitivities to tazobactam-piperacillin, imipenem, metronidazole and chloramphenicol, and low sensitivities to ampicillin, cefoperazone and vancomycin. Prevotella species showed good sensitivities to sulbactam-ampicillin, tazobactam-piperacillin, cefmetazole, imipenem, doripenem and metronidazole. Susceptibility rates to other drugs were slightly different depending on the bacterial species. Both Fusobacterium spp. and Porphyromonas spp. showed high sensitivities to many drugs. C. difficile was highly sensitive to vancomycin and metronidazole, having MIC90s of 0.5 µg/mL and ≤2 µg/mL, respectively.

Bacteremia due to high-level daptomycin-resistant Corynebacterium striatum: A case report with genetic investigation.

Corynebacterium striatum, generally considered an opportunistic organism in humans, has recently been known to develop high-level daptomycin resistance (HLDR) shortly after drug exposure. To date, however, only several such clinical isolates have been described in the literature and clinical background of the resistant pathogen remains to be elucidated. Here, we report a case involving a C. striatum strain with HLDR harboring novel nucleotide mutations, together with a review of the relevant literature. To the best of our knowledge, this is the first well-investigated clinical report from Japan including a genetic investigation. Considering the rapid emergence of HLDR C. striatum in vitro experiment, there could be a number of underreporting cases. Scrupulous attention is required when administering daptomycin for the treatment of C. striatum infections, even if the organism has initially exhibited susceptibility.

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.

Pasteurella multocida multiple intrapelvic abscesses in a young woman with uterine cervical cancer.

Pasteurella multocida, a zoonotic pathogen in humans, is known to be associated with skin and soft tissue infections following animal bites, but rarely causes visceral infections. We report a case of P. multocida-associated multiple intrapelvic abscesses in a young woman with uterine cervical cancer. A 29-year-old unmarried woman was referred to us because of prolonged high fever accompanying abdominal pain with muscular guarding. She had a domestic cat but denied of any bites or scratches before that. Computed tomography demonstrated ascites and multiple abscesses around her uterus. Her condition did not improve with an initial treatment with flomoxef, clindamycin, and azithromycin. Further, we performed percutaneous pus drainage and switched the antimicrobial therapy to a combination of piperacillin/tazobactam and minocycline for 10 days. Although P. multocida was isolated from vaginal culture, no organisms were isolated from the pus culture. However, further investigation with specimen-direct 16S rDNA analysis diagnosed P. multocida as possibly a single pathogen responsible for the intrapelvic infection. After taking oral levofloxacin for two weeks, no recurrence was reported. Although P. multocida is known as an animal-related pathogen, it can transmit to humans without apparent bites or scratches. The present case illustrates that P. multocida can cause intrapelvic abscess as a result of ascending genital infection.

Emergence of daptomycin non-susceptible coagulase-negative Staphylococci in patients with cardiovascular device infections: Two cases report investigated by whole genome analysis.

RATIONALE: Daptomycin (DAP) is a key drug for treating severe Staphylococcus infections. The emergence of DAP non-susceptible Staphylococcus aureus has been widely recognized in clinical situations, although the clinical status of DAP non-susceptible coagulase-negative Staphylococcus (CoNS) infections is unclear. We encountered 2 cases of cardiovascular device infections that were associated with DAP non-susceptible CoNS. PATIENT CONCERNS: The first case involved a 60-year-old woman with a pump pocket infection in a left ventricular assist device. DAP non-susceptible Staphylococcus capitis subsp. ureolyticus was isolated from a blood culture after treatment using vancomycin (10 days) and DAP (6 days). The second case involved a 71-year-old man with an aortic graft infection. DAP non-susceptible S capitis subsp. ureolyticus was detected in pus after treatment using vancomycin (2 weeks) and DAP (1 week) without complete removal and debridement. DIAGNOSIS: Cardiovascular device infections caused by DAP non-susceptible CoNS. INTERVENTIONS AND OUTCOMES: Whole genome sequencing of these strains revealed multiple mutations in genes that are related to DAP-non-susceptibility in S aureus, which created amino acid substitutions in mprF, dltAB, dltD, rpoC, yycG, cls2, pgsA, and vraSR. To the very best of our knowledge, the substitution patterns were not identical to those previously reported in DAP non-susceptibile S aureus. LESSONS: Clinicians should be cautious regarding the emergence of DAP non-susceptible CoNS, especially in cases with implanted prosthetic devices, inadequate debridement, and prior usage of vancomycin and DAP. Further studies are needed to understand the relevance of these genetic changes and DAP-non-susceptibility in CoNS strains.

Roseomonas mucosa bacteremia in a neutropenic child: A case report and literature review.

Roseomonas species is rarely found to be pathogenic to humans and there are few clinical cases that have been described in the literature. We report a case of Roseomonas mucosa bacteremia that involved a 9-year-old Japanese boy who was in a condition of febrile neutropenia caused by chemotherapy for cerebellar medulloblastoma. Conventional phenotyping failed to identify the organism; however, genetic analysis using 16S rDNA sequencing confirmed the pathogen to be R. mucosa. The patient recovered following treatment by meropenem without any complications. A literature review of pediatric cases of Roseomonas bacteremia identified 12 other documented cases, and these revealed that a common clinical situation for the infection is an immunocompromised state with malignancy and/or an indwelling intravenous catheter. Because of the low number of cases, the overall picture of Roseomonas bacteremia in children remains to be elucidated; however, the prognosis of the infection appears to be satisfactory.

Persistent methicillin-resistant Staphylococcus aureus bacteremia owing to placental abscess.

Staphylococcus aureus as a pathogen in human gestational membranes, a rather rare phenomenon, has recently been the focus of several researches. S. aureus forms biofilms on these membranes and potentially causes chorioamnionitis in pregnant women. We report a case of persistent methicillin-resistant S. aureus (MRSA) bacteremia owing to placental infection, causing chorioamnionitis and preterm birth. A 29-year-old Japanese woman at the 27th gestational week was diagnosed with acute promyelocytic leukemia and underwent all-trans retinoic acid therapy. Soon after hospitalization, the patient presented with persistent MRSA bacteremia of unknown origin. Despite various antimicrobial therapies, she experienced 12 MRSA bacteremia episodes over 6 weeks. However, after child birth, MRSA bacteremia disappeared without any complications. A pathologic examination of her placenta revealed placenta abscess, resulting in a diagnosis of MRSA-associated chorioamnionitis. Molecular analysis proved that a single MRSA strain (SCCmec Type IVa), which tested negative for Panton-Valentine leukocidin and toxic shock syndrome toxin-1, caused the obstinate infection. We should be aware that persistent MRSA bacteremia in pregnant women can originate from placental abscess.

Helicobacter cinaedi-associated Carotid Arteritis.

A 65-year-old Japanese man with bilateral carotid atherosclerosis presented with right neck pain and fever. Contrast-enhanced computed tomography suggested carotid arteritis, and carotid ultrasonography showed an unstable plaque. The patient developed a cerebral embolism, causing a transient ischemic attack. Helicobacter cinaedi was detected in blood culture, and H. cinaedi-associated carotid arteritis was diagnosed. Empirical antibiotic therapy was administered for 6 weeks. After readmission for recurrent fever, he was treated another 8 weeks. Although the relationship between H. cinaedi infection and atherosclerosis development remains unclear, the atherosclerotic changes in our patient's carotid artery might have been attributable to H. cinaedi infection.

Silent Native-valve Endocarditis Caused by Propionibacterium acnes.

We describe a rare case of Propionibacterium acnes native-valve endocarditis that silently progressed in a 67-year-old man with hybrid dialysis. The patient was scheduled for kidney transplantation, and pre-operative investigation incidentally detected a vegetative structure at his native mitral valve that had increased in size. He underwent cardiac surgery and P. acnes was detected in cultures of a resected cardiac valve specimen and blood. This case highlights that P. acnes can silently cause infective endocarditis in a native-valve, and that physicians should consider the possibility of infection when P. acnes is isolated in blood cultures.

Emergence of Carbapenem Non-susceptible Campylobacter coli after Long-term Treatment against Recurrent Bacteremia in a Patient with X-linked Agammaglobulinemia.

We herein report a case of recurrent Campylobacter coli bacteremia in a 37-year-old Japanese man with X-linked agammaglobulinemia (XLA). The patient experienced seven episodes of C. coli bacteremia over one year, with an erythematous rash intermittently emerged on the lower limbs. Although hospitalization for intravenous treatment was repeatedly recommended, he obstinately declined it. Following long-term oral antibiotic treatment with tebipenem and faropenem for the persistent infection, C. coli showed elevated minimum inhibitory concentrations to meropenem, a key drug for severe campylobacteriosis. Physicians should note that the overuse of antibiotics can lead to the emergence of carbapenem-non-susceptible Campylobacter strains.

Desulfovibrio desulfuricans bacteremia: A case report and literature review.

Desulfovibrio spp. are sulfate-reducing, anaerobic bacteria that are ubiquitously found in the environment. These organisms infrequently cause human infections, and the clinical characteristics of infection with Desulfovibrio spp. remain unclear. Here, we describe a case of Desulfovibrio desulfuricans bacteremia in an 88-year-old Japanese man with a past medical history of thoracic endovascular aortic repair (TEVAR). His chief complaint was hemoptysis for 2 weeks. A chest contrast-enhanced computed tomography demonstrated an enlarged thoracic aortic aneurysm surrounded by a ring-enhanced lesion, recognized as mediastinal abscess. Gram-negative spiral bacilli were detected in anaerobic blood culture. These bacteria could not be identified using conventional methods, but by analyzing a full base sequence of 16S rDNA, they were identified as D. desulfuricans subsp. desulfuricans. The patient underwent an emergent re-TEVAR, and the infection subsided after being treated with tazobactam/piperacillin and clindamycin, followed by metronidazole. A literature review of previous cases of D. desulfuricans bacteremia suggested that the pathogen was derived from bacterial translocation from the intestine in most cases. Desulfovibrio infection is presumably underestimated due to its infrequency, indolent growth, and difficulty in identification. Desulfovibrio spp. should be suspected when spiral rods are observed in anaerobic culture, and molecular analysis is required for accurate species-level differentiation of the pathogens. To better understand the pathogenicity of these fastidious organisms, further cases based on the exact bacterial identification should be investigated.