Nafamostat mesylate decreases skin flap necrosis in a mouse model of type 2 diabetes by protecting the endothelial glycocalyx

The success rate of flap tissue reconstruction has increased in recent years owing to advancements in microsurgical techniques. However, complications, such as necrosis, are still more prevalent in diabetic patients compared to non-diabetic individuals, presenting an ongoing challenge. To address this issue, many previous studies have examined vascular anastomoses dilation and stability, primarily concerning surgical techniques or drugs. In contrast, in the present study, we focused on microvascular damage of the peripheral microvessels in patients with diabetes mellitus and the preventative impact of nafamostat mesylate. Herein, we aimed to investigate the effects of hyperglycemia on glycocalyx (GCX) levels in mice with type 2 diabetes. We examined the endothelial GCX (eGCX) in skin flap tissue of 9-12-week-old type 2 diabetic mice (db/db mice) using a perforator skin flap and explored treatment with nafamostat mesylate. The growth rates were compared after 1 week. Heterotype (db/+) mice were used as the control group. Morphological examination of postoperative tissues was performed at 1, 3, 5, and 7 days post-surgery. In addition, db/db mice were treated with 30 mg/kg/day of nafamostat mesylate daily and were evaluated on postoperative day 7. Seven days after surgery, all db/db mice showed significant partial flap necrosis. Temporal observation of the skin flaps revealed a stasis-like discoloration and necrosis starting from the contralateral side of the remaining perforating branch. The control group did not exhibit flap necrosis, and the flap remained intact. In the quantitative assessment of endothelial glycans using lectins, intensity scoring showed that the eGCX in the db/db group was significantly thinner than that in the db/+ group. These results were consistent with the scanning electron microscopy findings. In contrast, treatment with nafamostat mesylate significantly improved the flap engraftment rate and suppressed eGCX injury. In conclusion, treatment with nafamostat mesylate improves the disrupted eGCX structure of skin flap tissue in db/db mice, potentially ameliorating the impaired capillary-to-venous return in the skin flap tissue.

[Adult-onset COVID-19-associated Fulminant Acute Encephalopathy with Elevated Cerebrospinal Fluid Interleukin-8: A Case Report]

A 26-year-old woman receiving immunosuppressive therapy for polymyositis was infected with COVID-19 (an omicron mutant strain) and presented with fever. On the second day after the onset, she was admitted to our hospital and developed status epilepticus. Brain magnetic resonance imaging on admission revealed abnormal symmetric hyperintensities in the bilateral putamen and around the dorsal horns of the lateral ventricle. Three days after admission, brain computed tomography revealed marked cerebral edema and herniation. The cerebrospinal fluid (CSF) cell count was normal, and the reverse transcription polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 was negative. Interleukin (IL)-2, 6, and 10 levels were within the normal range in both serum and CSF, whereas IL-8 levels in the CSF were markedly higher compared to serum levels. She had fulminant acute encephalopathy, suspected to be in the early stages of acute necrotizing encephalopathy (ANE). Steroid pulse therapy and intravenous infusions of remdesivir were ineffective, and the patient died of sepsis on the 26th day after admission. We demonstrated that ANE may occur even in patients infected with Omicron strains and speculated that the pathogenesis in this case might be associated with intrathecal IL-8 production by microglial activation.

First case of necrotizing fasciitis and septicemia caused by Pigmentibacter ruber

We herein report the first case of necrotizing fasciitis caused by Pigmentibacter ruber. The isolated strain could not be identified by biochemical characterization and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The isolated strain was identified as P. ruber by 16S ribosomal RNA and whole genome sequencing. Although much remains unknown about the pathogenicity of this bacterial specie in humans, it has been revealed to cause life-threatening infections, such as septicemia and necrotizing fasciitis. Since the isolate was highly resistant to beta-lactams, it could be difficult to treat with antimicrobial therapy. Thus further documentation of cases and analyses are needed.

Urinary liver-type fatty acid-binding protein levels may be associated with the occurrence of acute kidney injury induced by trauma

Introduction

Acute kidney injury (AKI), with a fatality rate of 8.6%, is one of the most common types of multiorgan failure in the intensive care unit (ICU). Thus, AKI should be diagnosed early, and early interventions should be implemented. Urinary liver-type fatty acid-binding protein (L-FABP) could aid in the diagnosis of AKI.

Methods

In this prospective, single-center, observational study, we included 100 patients with trauma. Urinary L-FABP levels were measured using a semi-quantitative rapid assay kit 6 and 12 h after injury. Negative, weakly positive, and strongly positive urinary L-FABP levels were examined using two protocols. Using protocol 1, measurements were performed at 6 h after injury negative levels were considered "negative," and weakly positive and strongly positive levels were considered "positive." Using protocol 2, strongly positive levels at 6 h after injury were considered "positive," and negative or weakly positive levels at 6 h after injury were considered "positive" if they were weakly positive or positive at 12 h after injury.

Results

Fifteen patients were diagnosed with AKI. Using protocol 1, the odds ratio (OR) was 20.55 (p = 0.001) after adjustment for the injury severity score (ISS), contrast media use, and shock index. When the L-FABP levels at 6 and 12 h were similarly adjusted for those three factors, the OR was 18.24 (p < 0.001). The difference in ORs for protocols 1 and 2 was 1.619 (p = 0.04).

Discussion

Associations between urinary L-FABP and AKI can be examined more precisely by performing measurements at 6 and 12 h after injury than only one time at 6 h.

Impact of augmented renal clearance on anticoagulant therapy in critically ill patients with coronavirus disease 2019: A retrospective cohort study

INTRODUCTION

This study aimed to determine the impact of augmented renal clearance (ARC) on anticoagulation therapy in critically ill patients with coronavirus disease 2019 (COVID-19).

METHODS

This retrospective cohort study included adult patients with severe COVID-19 with ARC who had been treated at our hospital between 2020 and 2021. We measured the estimated glomerular filtration rate calculated by the Chronic Kidney Disease Epidemiology Collaboration formula (eGFRCKD-EPI) every morning, and ARC condition was defined as eGFRCKD-EPI ≥ 130 mL/min/1.73 m2. Multivariate regression analysis with Huber-White sandwich estimator was performed to examine the association of unfractionated heparin (UH) dosage between blood test timings with activated partial thromboplastin time (APTT) compared with and without ARC.

RESULTS

We identified 38 enrolled patients: seven and 31 in the ARC and non-ARC groups, respectively. In the ARC coexisting condition, a higher dose of UH, which corresponded to the total dose in 24 h from the previous day, was required to achieve the same APTT prolongation, with a significant difference (p < 0.001).

CONCLUSIONS

Our study suggests that careful monitoring and consideration of higher UH doses in critically ill patients with COVID-19 is necessary because anticoagulation failure can occur during ARC.

Balamuthia mandrillaris amoebic encephalitis mimicking tuberculous meningitis

A 76-year-old female with no apparent immunosuppressive conditions and no history of exposure to freshwater and international travel presented with headache and nausea 3 weeks before the presentation. On admission, her consciousness was E4V4V6. Cerebrospinal fluid analysis showed pleocytosis with mononuclear cell predominance, elevated protein, and decreased glucose. Despite antibiotic and antiviral therapy, her consciousness and neck stiffness gradually worsened, right eye-movement restriction appeared, and the right direct light reflex became absent. Brain magnetic resonance imaging revealed hydrocephalus in the inferior horn of the left lateral ventricle and meningeal enhancement around the brainstem and cerebellum. Tuberculous meningitis was suspected, and pyrazinamide, ethambutol, rifampicin, isoniazid, and dexamethasone were started. In addition, endoscopic biopsy was performed from the white matter around the inferior horn of the left lateral ventricle to exclude brain tumor. A brain biopsy specimen revealed eosinophilic round cytoplasm with vacuoles around blood vessels, and we diagnosed with amoebic encephalitis. We started azithromycin, flucytosine, rifampicin, and fluconazole, but her symptoms did not improve. She died 42 days after admission. In autopsy, the brain had not retained its structure due to autolysis. Hematoxylin and eosin staining of her brain biopsy specimen showed numerous amoebic cysts in the perivascular brain tissue. Analysis of the 16S ribosomal RNA region of amoebas from brain biopsy and autopsy specimens revealed a sequence consistent with Balamuthia mandrillaris. Amoebic meningoencephalitis can present with features characteristic of tuberculous meningitis, such as cranial nerve palsies, hydrocephalus, and basal meningeal enhancement. Difficulties in diagnosing amoebic meningoencephalitis are attributed to the following factors: (1) excluding tuberculous meningitis by microbial testing is difficult, (2) amoebic meningoencephalitis has low incidence and can occur without obvious exposure history, (3) invasive brain biopsy is essential in diagnosing amoebic meningoencephalitis. We should recognize the possibility of amoebic meningoencephalitis when evidence of tuberculosis meningitis cannot be demonstrated.

Recombinant antithrombin attenuates acute kidney injury associated with rhabdomyolysis: an in vivo animal study

BACKGROUND

Rhabdomyolysis is characterized by the destruction and necrosis of skeletal muscle tissue, resulting in acute kidney injury (AKI). Recombinant antithrombin (rAT) has DNA repair and vascular endothelial-protection properties. Herein, we investigated whether rAT therapy has beneficial effects against rhabdomyolysis-induced AKI. Ten-week-old male B6 mice were injected with 5 mL/kg of 50% glycerol intramuscularly in the left thigh after 24 h of fasting to create a rhabdomyolysis mouse model. Further, 750 IU/kg rAT was injected intraperitoneally at 24 and 72 h after the rhabdomyolysis model was established. The mice were euthanized after 96 h for histological analysis. Saline was administered to mice in the control group.

RESULTS

Blood tests show elevated serum creatinine, urea nitrogen, and neutrophil gelatinase-associated lipocalin levels in rhabdomyolysis. Loss of tubular epithelial cell nuclei and destruction of the tubular luminal surface structure was observed in the untreated group, which improved with rAT treatment. Immunostaining for Ki-67 showed increased Ki-67-positive nuclei in the tubular epithelial cells in the rAT group, suggesting that rAT may promote tubular epithelial cell regeneration. The microvilli of the brush border of the renal tubules were shed during rhabdomyolysis, and rAT treatment reduced this injury. The vascular endothelial glycocalyx, which is usually impaired by rhabdomyolysis, became functional following rAT treatment.

CONCLUSIONS

Treatment with rAT suppressed rhabdomyolysis-induced AKI, suggesting that rAT therapy may be a novel therapeutic approach.

Next-generation sequencing-based detection of Ureaplasma in the gastric fluid of neonates with respiratory distress and chorioamnionitis

BACKGROUND

Respiratory distress is common in neonates admitted to neonatal intensive care units. Additionally, infectious diseases such as intrauterine infections or vertical transmission are important underlying causes of respiratory failure. However, pathogens often cannot be identified in neonates, and there are many cases in which antibacterial drugs are empirically administered. Next-generation sequencing (NGS) is advantageous in that it can detect trace amounts of bacteria that cannot be detected by culturing or bacteria that are difficult to cultivate. However, there are few reports on the diagnosis of infectious diseases using NGS in the neonatal field, especially those targeting respiratory distress.

OBJECTIVE

The purpose of our study was to investigate the microorganisms associated with neonatal respiratory distress and to determine whether less invasive collection specimens such as plasma and gastric fluid are useful.

METHODS

Neonates were prospectively recruited between January and August 2020 from Nagoya University Hospital. The inclusion criteria were as follows: 1) admission to the neonatal intensive care unit; 2) respiratory distress presentation within 48 h of birth; and 3) suspected infection, collection of blood culture, and administration of antibiotics. Plasma samples and blood cultures were simultaneously collected. Gastric fluid samples were also collected if the patient was not started on enteral nutrition. Information on the patients and their mothers were collected from the medical records. DNA was extracted from 140 µL of plasma and gastric fluid samples. DNA sequencing libraries were prepared, and their quality was analyzed. DNA libraries were sequenced using high-throughput NGS. The NGS data of plasma and gastric fluid samples were analyzed using the metagenomic pipeline PATHDET, which calculated the number of reads assigned to microorganisms and their relative abundance. Putative pathogens were listed.

RESULTS

Overall, 30 plasma samples and 25 gastric fluid samples from 30 neonates were analyzed. Microorganism-derived reads of gastric fluid samples were significantly higher than those of plasma samples. Transient tachypnea of the newborn was the most common cause of respiratory distress with 13 cases (43%), followed by respiratory distress syndrome with 7 cases (23%). There were 8 cases (29%) of chorioamnionitis and 7 cases (25%) of funisitis pathologically diagnosed. All blood cultures were negative, and only two gastric fluid cultures were positive for group B Streptococcus (Patient 15) and Candida albicans (Patient 24). Putative pathogens that met the positive criteria for PATHET were detected in four gastric fluid samples, one of which was group B Streptococcus from Patient 15. In the gastric fluid sample of Patient 24, Candida albicans were detected by NGS but did not meet the positive criteria for PATHDET. Cluster analysis of the plasma samples divided them into two study groups, and the indicator genera of each cluster (Phormidium or Toxoplasma) are shown in Figure 1. Clinical findings did not show any significant differences between the two groups. Cluster analysis of the gastric fluid samples divided them into three study groups, and the indicator genera of each cluster (Ureaplasma, Nostoc, and Streptococcus) are shown in Figure 2. The incidence rate of chorioamnionitis was significantly higher in Ureaplasma group than in the other two groups.

CONCLUSION

Gastric fluid may be useful for assessing neonatal patients with respiratory distress. To the best of our knowledge, this was the first study to reveal that the presence of Ureaplasma in the gastric fluid of neonates with respiratory distress was associated with chorioamnionitis. The early diagnosis of intra-amniotic infections using gastric fluid and its treatment may change the treatment strategy for neonatal respiratory distress. Screening for Ureaplasma in neonates with respiratory distress may reduce the need for empirical antibiotic administration. Further research is required to confirm these findings.

Decreased neutrophil counts prolong inflammation in acute pancreatitis and cause inflammation spillover to distant organs

BACKGROUND/OBJECTIVE

Acute pancreatitis is an aseptic inflammation caused by pathologically activated pancreatic enzymes and inflammatory mediators produced secondarily by neutrophils and other inflammatory cells and is one of the most difficult diseases to treat. This study aimed to investigate the role of neutrophils in pancreatitis by examining tissue dynamics.

METHODS

We created a model of caerulein-induced pancreatitis in 12-week-old male granulocyte colony-stimulating factor knockout mice (G-CSF-KO) and wild-type littermate control mice (six intraperitoneal injections of caerulein [80 μg/kg body weight] at hourly intervals for 2 days). Mice were sacrificed 0, 3, 6, 12, 24, 36, 48, 72, and 168 h after caerulein administration and examined histologically.

RESULTS

The survival rate after one week of caerulein administration was 100 % in the control mice, whereas it was significantly lower (10 %) in the G-CSF-KO mice. Histological examination revealed significant hemorrhage and inflammatory cell migration in the G-CSF-KO mice, indicating prolonged inflammation.

CONCLUSION

Prolonged inflammation was observed in the G-CSF-KO mice. Tissue cleanup by neutrophils during the acute phase of inflammation may influence healing through the chronic phase.

Delayed diagnosis of Lemierre's syndrome in a patient with severe coronavirus disease 2019: importance of comprehensive oral and neck examination - a case report

BACKGROUND

Given the widespread prevalence of the coronavirus disease 2019 (COVID-19), oral and neck examinations tend to be avoided in patients with suspected or confirmed COVID-19. This might delay the diagnosis of conditions such as Lemierre's syndrome, which involves symptoms resembling COVID-19-related throat manifestations.

CASE PRESENTATION

A 24-year-old man without any underlying conditions was diagnosed with COVID-19 7 days before presentation. He was admitted to another hospital 1 day before presentation with severe COVID-19 and suspected bacterial pneumonia; accordingly, he was started on treatment with remdesivir and meropenem. Owing to bacteremic complications, the patient was transferred to our hospital for intensive care. On the sixth day, the patient experienced hemoptysis; further, a computed tomography (CT) scan revealed new pulmonary artery pseudoaneurysms. Successful embolization was performed to achieve hemostasis. In blood cultures conducted at the previous hospital, Fusobacterium nucleatum was isolated, suggesting a cervical origin of the infection. A neck CT scan confirmed a peritonsillar abscess and left internal jugular vein thrombus; accordingly, he was diagnosed with Lemierre's syndrome. The treatment was switched to ampicillin/sulbactam, based on the drug susceptibility results. After 6 weeks of treatment, the patient completely recovered without complications.

CONCLUSION

This case highlights the significance of thorough oral and neck examinations in patients with suspected or diagnosed COVID-19 for the detection of throat and neck symptoms caused by other conditions.

A Japanese retrospective study of non-tuberculous mycobacterial infection in children, adolescents, and young adult patients with hematologic-oncologic diseases

Non-tuberculous mycobacterial infection (NTM) is rare in healthy children, with lymphadenitis being the most common presentation. Immunocompromised populations are known to be at high risk, but the clinical picture of NTM infection in pediatric hematology/oncology patients is unclear. In this nationwide retrospective analysis of patients under the age of 40 treated in Japanese pediatric hematology/oncology departments who developed NTM infection between January 2010 and December 2020, 36 patients (21 patients with hematopoietic stem cell transplantation (HSCT) and 15 nontransplant patients) were identified. Post-transplant patients were infected with NTM at 24 sites, including the lungs (n = 12), skin and soft tissues (n = 6), bloodstream (n = 4), and others (n = 2). Nine of twelve patients with pulmonary NTM infection had a history of pulmonary graft-versus-host disease (GVHD), and rapid-growing mycobacteria (RGM) were isolated from five of them. In nontransplant patients, the primary diseases were acute lymphoblastic leukemia (ALL; n = 5), inborn errors of immunity (IEI; n = 6), and others (n = 4). All cases of ALL had bloodstream infections with RGM, whereas all cases of IEI were infected with slow-growing mycobacteria (SGM). In summary, three typical clinical scenarios for pediatric hematology/oncology patients have been established: RGM-induced pulmonary disease in patients with pulmonary GVHD, RGM bloodstream infection in patients with ALL, and SGM infection in patients with IEI. Our findings suggest that NTM must be regarded as a pathogen for infections in these high-risk patients, especially those with pulmonary GVHD, who may require active screening for NTM.

Investigation of the relationship between intradialytic hypotension during hemodialysis and serum syndecan-1 concentration

Intradialytic hypotension and arrhythmias are complications of hemodialysis. They are associated with decreased intravascular volume due to reduced ultrafiltration volume, cardiac function, and arterial tone. The vascular endothelial glycocalyx, which exists on the surface of healthy vascular endothelial cells and maintains vascular permeability, has been suggested to be impaired by hemodialysis. This single-center retrospective study evaluated the association between syndecan-1, an endothelial glycocalyx dysfunction marker, and complications of hemodialysis. We enrolled 92 patients who underwent outpatient hemodialysis at Gifu Seiryu Hospital from April to July 2022 (346 hemodialysis sessions). The median duration and time of hemodialysis were 40 months and 4.1 h, respectively. Median serum syndecan-1 levels were 67.7 ng/mL before and 98.3 ng/mL after hemodialysis. Hemodialysis complications were noted in 68 sessions, all of which were hypotension. No correlation between pre-hemodialysis syndecan-1 levels and the incidence of complications was observed. However, a positive correlation between the amount of change in syndecan-1 levels before and after hemodialysis and the incidence of hemodialysis complications was noted. Conversely, syndecan-1 levels did not correlate with brain or atrial natriuretic peptides, suggesting that impairment of the vascular endothelial glycocalyx may be a possible cause of intradialytic hypotension and may be useful in preventing intradialytic hypotension.

Multiple diagnostic examinations are effective for the early diagnosis of scrofuloderma

Although scrofuloderma is the most common subtype of cutaneous tuberculosis, its diagnosis is often delayed. In this case, ciprofloxacin was first administered as only Pseudomonas aeruginosa was detected by initial culture tests. Mycobacterium tuberculosis is usually susceptible to quinolone antibiotics, hence the partial improvement in inflammatory symptoms and subsequent delay in diagnosis. Our case serves as a reminder that we should always be aware of the possibility of cutaneous tuberculosis being the cause of an abscess, especially when the abscess is not completely resolved by antibiotics. Moreover, our case reminds us that it is necessary to conduct repeated culture tests, rather than relying purely on polymerase chain reaction (PCR) results, given that cases of PCR-negative acid-fast bacilli (AFB) culture-positive scrofuloderma have been reported. Fine needle aspiration is a less invasive and useful way to collect culture samples.

Recombinant thrombomodulin may protect cardiac capillary endothelial glycocalyx through promoting Glypican-1 expression under experimental endotoxemia

Introduction

Myocardial dysfunction occurs in patients with sepsis due to vascular endothelial injury. Recombinant human thrombomodulin (rhTM) attenuates vascular endothelial injuries through endothelial glycocalyx (eGC) protection.

Hypothesis

We hypothesized that rhTM attenuates myocardial dysfunction via the inhibition of vascular endothelial injury during sepsis.

Methods

Ten-week-old male C57BL6 mice were injected intraperitoneally with 20 mg/kg of lipopolysaccharide (LPS). In rhTM-treated mice, rhTM was injected intraperitoneally at 3 and 24 h after LPS injection. Saline was injected intraperitoneally as control. To assess for eGC injury, intensity score was measured 48 h after the LPS injection. To confirm vascular endothelial injuries, ultrastructural analysis was performed using scanning (SEM) and transmission electron microscopy (TEM).

Results

The survival rate of the rhTM group at 48 h after LPS injection was significantly higher than that of the control group (68% vs. 17%, p < 0.05). The serum level of troponin I in the rhTM group was lower than that in the control (2.2 ± 0.4 ng/dL vs 9.4 ± 1.1 ng/dL, p < 0.05). The expression of interleukin-6 (IL-6) was attenuated in the rhTM-treated group than in the control (65.3 ± 15.3 ng/mL vs 226.3 ± 19.4 ng/mL, p < 0.05). The serum concentration of syndecan-1, a marker of glycocalyx damage, was significantly decreased 48 h post-administration of LPS in the rhTM-treated group than in the control group. In ultrastructural analysis using SEM and TEM, eGC peeled off from the surface of the capillary lumen in the control. Conversely, the eGC injury was attenuated in the rhTM group. Gene set enrichment analysis revealed that osteomodulin, osteoglycin proline/arginine-rich end leucine-rich repeat protein, and glypican-1, which are proteoglycans, were preserved by rhTM treatment. Their protein expression was retained in endothelial cells.

Conclusion

rhTM attenuates sepsis-induced myocardial dysfunction via eGC protection.

Syndecan-1 as a severity biomarker for patients with trauma

Tissue injury and hemorrhage induced by trauma lead to degradation of the endothelial glycocalyx, causing syndecan-1 (SDC-1) to be shed into the blood. In this study, we investigated whether serum SDC-1 is useful for evaluating trauma severity in patients. A single-center, retrospective, observational study was conducted at Gifu University Hospital. Patients transported to the emergency room for trauma and subsequently admitted to the intensive care unit from January 2019 to December 2021 were enrolled. A linear regression model was constructed to evaluate the association of serum SDC-1 with injury severity score (ISS) and probability of survival (Ps). A total of 76 trauma patients (54 men and 22 women) were analyzed. ISS was significantly associated with serum SDC-1 level in trauma patients. Among the six body regions defined in the AIS used to calculate the ISS score, “chest” and “abdominal or pelvic contents” were significantly associated with serum SDC-1 level, and “extremities or pelvic girdle” also tended to show an association with serum SDC-1 level. Moreover, increasing serum SDC-1 level was significantly correlated with decreasing Ps. Serum SDC-1 may be a useful biomarker for monitoring the severity of trauma in patients. Further large-scale studies are warranted to verify these results.

＜Editors' Choice＞ Multicenter survey for carbapenemase-producing Enterobacterales in central Japan

Carbapenemase-producing Enterobacterales (CPE) raise concerns about the treatment options for infectious diseases and infection control. We conducted a multicenter study to clarify the molecular epidemiology of CPE in the Aichi Prefecture during the first 3-month period from 2015 to 2019. Carbapenemase production was screened using a modified carbapenem inactivation method, and the genotypes of the carbapenemase genes were determined by polymerase chain reaction sequencing. Genetic relatedness was analyzed using multilocus sequence typing (MLST). Twenty-four hospitals participated in this study. Of the 56,494 Enterobacterales strains detected during the study period, 341 (0.6%) that met the susceptibility criteria were analyzed. Sixty-five of the 341 strains were determined to be CPE, with an incidence rate of 0.12% (65/56,494). The bacterial species responsible for CPE were Klebsiella pneumoniae (n = 24), Enterobacter cloacae complex (n = 23), Klebsiella oxytoca (n = 10), and Escherichia coli (n = 8). Most of the carbapenemase genotypes were IMP-1 (58/65), and only three were IMP-6 types. Three E. coli strains that produced NDM-5 were detected. MLST analysis showed that Sequence type (ST) 78 was predominant in E. cloacae complex CPE (14/23, 60.9%). Meanwhile, various STs were detected in carbapenemase-producing (CP) K. pneumoniae, of which ST37 and ST517 were the most common. The incidence rate of CPE in this region was comparable to national data. This 3-month surveillance revealed the spread of ST78 of CP E. cloacae complex and ST517 and ST592 of CP K. pneumoniae across hospitals, indicating the need to strengthen regional infection control programs.

Post-exposure prophylaxis to prevent varicella in immunocompromised children

Background

Varicella-zoster virus (VZV) infection can cause life-threatening events in immunocompromised patients. Post-exposure prophylaxis (PEP) is required to prevent secondary VZV infection. Limited evidence is available for the use of acyclovir (ACV)/valacyclovir (VCV) as PEP.

Methods

Herein, we retrospectively analyzed immunocompromised paediatric patients with significant exposure to VZV. Patients administered PEP were categorized into four groups: 1) ACV/VCV group; 2) intravenous immunoglobulin (IVIG) group; 3) ACV/VCV/IVIG group; 4) vaccine group.

Results

Among 69 exposure events, 107 patients were administered PEP (91, ACV/VCV; 16, ACV/VCV/IVIG) and 10 patients did not receive PEP (non-PEP group). The index case was diagnosed based on clinical symptoms in 55 cases (79.7%). Fourteen cases (20.3%) were confirmed using direct virological diagnostic procedures. In the PEP group, only 2 patients (2.2%) developed secondary VZV infections. Additionally, 2 patients in the non-PEP group (20.0%) developed secondary VZV infection. The incidence of secondary VZV infection was significantly lower in the PEP group than in the non-PEP group (P=0.036). Among patients administered PEP, no antiviral drug-induced side effects were detected.

Conclusions

Antiviral agents administered as PEP are effective and safe for preventing VZV infections in immunocompromised patients. Rapid virological diagnosis of index cases might allow efficient administration of PEP after significant exposure to VZV infection.

Clinical characteristics and treatment outcomes of carbapenem-resistant Enterobacterales infections in Japan

OBJECTIVES

The dissemination of difficult-to-treat carbapenem-resistant Enterobacterales (CRE) is of great concern. We clarified the risk factors underlying CRE infection mortality in Japan.

METHODS

We conducted a retrospective, multicentre, observational cohort study of patients with CRE infections at 28 university hospitals from September 2014 to December 2016, using the Japanese National Surveillance criteria. Clinical information, including patient background, type of infection, antibiotic treatment, and treatment outcome, was collected. The carbapenemase genotype was determined using PCR sequencing. Multivariate analysis was performed to identify the risk factors for 28-day mortality.

RESULTS

Among the 179 patients enrolled, 65 patients (36.3%) had bloodstream infections, with 37 (20.7%) infections occurring due to carbapenemase-producing Enterobacterales (CPE); all carbapenemases were of IMP-type (IMP-1: 32, IMP-6: 5). Two-thirds of CPE were identified as Enterobacter cloacae complex. Combination therapy was administered only in 46 patients (25.7%), and the 28-day mortality rate was 14.3%. Univariate analysis showed that solid metastatic cancer, Charlson Comorbidity Index ≥3, bloodstream infection, pneumonia, or empyema, central venous catheters, mechanical ventilation, and prior use of quinolones were significant risk factors for mortality. Multivariate analysis revealed that mechanical ventilation (OR: 6.71 [1.42-31.6], P = 0.016), solid metastatic cancers (OR: 5.63 [1.38-23.0], P = 0.016), and bloodstream infections (OR: 3.49 [1.02-12.0], P = 0.046) were independent risk factors for 28-day mortality.

CONCLUSION

The significant risk factors for 28-day mortality in patients with CRE infections in Japan are mechanical ventilation, solid metastatic cancers, and bloodstream infections.

Genetic and epidemiological analysis of ESBL-producing Klebsiella pneumoniae in three Japanese university hospitals

INTRODUCTION

We aimed to clarify the genetic background and molecular epidemiology of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae (K. pneumoniae) at three geographically separated university hospitals in Japan.

METHODS

From January 2014 to December 2016, 118 ESBL-producing K. pneumoniae (EPKP) strains that were detected and stored at three university hospitals were collected. Molecular epidemiological analysis was performed using enterobacterial repetitive intergenic consensus (ERIC)-polymerase chain reaction (PCR) and multi-locus sequence typing (MLST). The ESBL type was determined using the PCR-sequence method. The presence of plasmid-mediated fluoroquinolone resistance (PMQR) genes was analyzed by PCR. We compared the relationships between PMQR gene possession/quinolone resistance-determining region (QRDR) mutation and levofloxacin (LVFX)/ciprofloxacin (CPFX) susceptibility.

RESULTS

The detection rate of EPKP was 4.8% (144/2987 patients). MLST analysis revealed 62 distinct sequence types (STs). The distribution of STs was diverse, and only some EPKP strains had the same STs. ERIC-PCR showed discriminatory power similar to that of MLST. The major ESBL genotypes were CTX-M-15-, CTX-M-14-, and SHV-types, which were detected in 47, 30, and 27 strains, respectively. Ninety-one out of 118 strains had PMQR genes and 14 out of 65 strains which were not susceptible to CPFX had QRDR mutations, and the accumulation of PMQR genes and QRDR mutations tended to lead to higher minimum inhibitory concentrations (MICs) of LVFX.

CONCLUSIONS

At three geographically separated university hospitals in Japan, the epidemiology of EPKP was quite diverse, and no epidemic strains were found, whereas CTX-M-14 and CTX-M-15 were predominant.

Measuring the Concentration of Serum Syndecan-1 to Assess Vascular Endothelial Glycocalyx Injury During Hemodialysis

Glycocalyx is present on the surface of healthy endothelium, and the concentration of serum syndecan-1 can serve as an injury marker. This study aimed to assess endothelial injury using serum syndecan-1 as a marker of endothelial glycocalyx injury in patients who underwent hemodialysis. In this single-center, retrospective, observational study, 145 patients who underwent hemodialysis at the Gifu University Hospital between March 2017 and December 2019 were enrolled. The median dialysis period and time were 63 months and 3.7 h, respectively. The serum syndecan-1 concentration significantly increased from 124.6 ± 107.8 ng/ml before hemodialysis to 229.0 ± 138.1 ng/ml after hemodialysis (P &lt; 0.001). Treatment with anticoagulant nafamostat mesylate inhibited hemodialysis-induced increase in the levels of serum syndecan-1 in comparison to unfractionated heparin. Dialysis time and the change in the syndecan-1 concentration were positively correlated. Conversely, the amount of body fluid removed and the changes in the syndecan-1 concentration were not significantly correlated. The reduction in the amount of body fluid removed and dialysis time inhibited the change in the syndecan-1 levels before and after hemodialysis. In conclusion, quantitative assessment of the endothelial glycocalyx injury during hemodialysis can be performed by measuring the serum syndecan-1 concentration, which may aid in the selection of appropriate anticoagulants, reduction of hemodialysis time, and the amount of body fluid removed.

Bursitis, Bacteremia, and Disseminated Infection of Mycobacteroides (Mycobacterium) abscessus subsp. massiliense

We herein report a 59-year-old woman with a 2-year history of chronic bursitis of the hand who took 50 mg/day prednisolone for several autoimmune diseases. Mycobacteroides abscessus subsp. massiliense was isolated from the abscess and blood culture. Combination therapy (imipenem/cilastatin, amikacin, and clarithromycin) was administered for a month. Two months later, M. massiliense was detected from a blood culture again, and disseminated lesions were found. Clarithromycin and sitafloxacin were administered following eight weeks of the same regimen. Six months after the diagnosis, M. massiliense was isolated from a blood culture, and she expired due to multiple organ failure.

Efficacy of favipiravir for an end stage renal disease patient on maintenance hemodialysis infected with novel coronavirus disease 2019

BACKGROUND

Novel coronavirus disease 2019 (COVID-19) refers to infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogen, and has spread to pandemic levels since its inception in December 2019. While several risk factors for severe presentation have been identified, the clinical course for end-stage renal disease (ESRD) patients on maintenance hemodialysis with COVID-19 has been unclear. Previous studies have revealed that some antiviral agents may be effective against COVID-19 in the general population, but the pharmacokinetics and pharmacodynamics of these agents in ESRD patients remain under investigation. Favipiravir, an antiviral agent developed for treatment of influenza, is one candidate treatment for COVID-19, but suitable dosages for patients with renal insufficiency are unknown. Here we provide a first report on the efficacy of favipiravir in a patient with ESRD undergoing hemodialysis.

CASE PRESENTATION

The case involved a 52-year-old woman with COVID-19 who had been undergoing maintenance hemodialysis three times a week for 3 years due to diabetic nephropathy. She had initially been treated with lopinavir/ritonavir and ciclesonide for 5 days, but developed severe pneumonia requiring invasive positive-pressure ventilation. Those antiviral agents were subsequently switched to favipiravir. She recovered gradually, and after 2 weeks was extubated once the viral load of SARS-CoV-2 fell below the limit of detection. Although concentrations of several biliary enzymes were elevated, no major adverse events were observed.

CONCLUSION

Favipiravir may be an effective option for the treatment of COVID-19-infected patients with ESRD.

Molecular epidemiological analysis and risk factors for acquisition of carbapenemase-producing Enterobacter cloacae complex in a Japanese university hospital

Background

To clarify the molecular epidemiology of carbapenem-resistant Enterobacter cloacae complex (CREC) and the risk factors for acquisition of carbapenemase-producing E. cloacae complex (CPEC).

Methods

Using clinical CREC isolates detected in a Japanese university hospital over 4 years, carbapenemase production was screened with phenotypic methods. Carbapenemase genes were analysed by PCR and sequencing. Molecular epidemiological analyses were conducted with repetitive extragenic palindromic (REP)-PCR and multilocus sequence typing (MLST). CRECs were identified to the subspecies level by hsp60 sequencing. Whole-genome sequencing of plasmids was conducted. A case-control study was performed to identify risk factors for acquisition of CPEC among patients with CREC.

Results

Thirty-nine CRECs including 20 CPECs carrying bla _IMP-1 were identified. Patients with CPEC had longer hospital stay before detection (26.5 days vs. 12 days, p = 0.008), a urinary catheter (odds ratio [OR], 5.36; 95% confidence interval [CI], 1.14-30.9; p = 0.023), or intubation (OR, 7.53; 95% CI, 1.47-53.8; p = 0.008) compared to patients without CPEC. Four genetically closely related CPEC clusters were observed, which showed that three of four CPEC clusters corresponded to E. asburiae (ST 53), E. hormaechei subsp. steigerwaltii (ST 113 and ST 1047) and E. cloacae subsp. cloacae (ST 513) by MLST and hsp60 sequencing. Seven representative plasmids shared structures with class I integron containing bla _IMP-1 and IncHI2A replicon type.

Conclusions

A longer hospital stay, presence of a urinary catheter, and intubation are risk factors for CPEC acquisition. In addition to horizontal transmission of genetically indistinguishable CPECs, IncHI2A plasmid carrying bla _IMP-1 appeared to be transferred among genetically different ECs.

Risk factors for and role of OprD protein in increasing minimal inhibitory concentrations of carbapenems in clinical isolates of Pseudomonas aeruginosa

PURPOSE

This study examined the risk factors for, and molecular mechanisms underlying, the increase in carbapenem minimum inhibitory concentrations (MICs) in clinical isolates of Pseudomonas aeruginosa.

METHODOLOGY

Consecutive clinical isolates of P. aeruginosa were collected. The MicroScan WalkAway system detected more than fourfold increases in the MICs of carbapenems in P. aeruginosa isolates serially recovered from some patients during their clinical course. The clinical risk factors associated with this increase were examined by multiple logistic regression analysis. Western blot analysis and nucleotide sequencing of the oprD gene of 19 clonally related and paired P. aeruginosa isolates from the same patients were undertaken to examine the mechanisms underlying the increase in MICs.

RESULTS

The results showed that prior use of carbapenems (OR, 2.799; 95 % CI, 1.088-7.200; P=0.033) and the use of ventilators or tracheostomies (OR, 2.648; 95 % CI, 1.051-6.671; P=0.039) were risk factors for increased carbapenem MICs. Analysis of the underlying mechanisms revealed that loss of functional OprD protein due to mutation of the oprD gene tended to occur in P. aeruginosa isolates with imipenem MICs of more than 8 µg ml^-1; a reduction in OprD expression was observed in P. aeruginosa isolates with imipenem MICs of 4 or 8 µg ml^-1. This difference in the resistance mechanism was not correlated with the MICs of meropenem.

CONCLUSION

This difference in the resistance mechanism of P. aeruginosa indicates a critical breakpoint at an imipenem MIC of 8 µg ml^-1, in accordance with EUCAST criteria. Reducing carbapenem use will prevent P. aeruginosa clinical isolates from developing resistance to carbapenems.

Comprehensive Detection of Pathogens in Immunocompromised Children with Bloodstream Infections by Next-generation Sequencing

Background

Bloodstream infection (BSI) is a severe complication in immunocompromised patients. Prompt identification of causative microorganisms would improve the outcome of BSI due to optimization of antimicrobial treatment. Next-generation sequencing (NGS) allows us to analyze comprehensively and quantitatively all microorganisms present in a clinical sample in comparison with blood culture. However, there are currently no established methods to identify causative pathogens by NGS.

Methods

BSI was defined by the following criteria: (i) pathogen isolated from blood culture and (ii) fever ≥38.0°C or C-reactive protein >1.0mg/dl. Thirty-five pediatric patients (12 with BSI and 23 with suspected BSI/negative blood culture) were enrolled. Plasma/serum samples were used for sequencing and the results were compared with those from blood culture. The bacterial reads per million reads of the sequence depth (BR) and relative importance values of the dominant bacteria (P1) were applied to identify causative pathogens.

Results

Sequencing reads of bacteria isolated in blood culture were identified by NGS in all plasma/serum samples at the onset of BSI. Additionally, bacteria isolated in blood culture were identical to the dominant bacteria by NGS in 8 of 12 patients with BSI. Causative microorganisms were detected when the NGS results fulfilled the criteria of BR >200 and P1 >0.5. In two patients with catheter-related BSI, causative bacteria were detected in the plasma/serum at 7 days before disease onset. Causative pathogens (Tatlockia micdadei, Escherichia coli, and human adenovirus 2) were identified in three of 23 patients in the suspected BSI group. A total of 62 resistance genes were detected in nine patients with sequences covering 5–100% of references.

Conclusion

An NGS-based approach has great potential for analysis of causative microorganisms in BSI and may help to diagnose a disease before disease onset. Antimicrobial resistance genes can also be found through sequence data processing.

Disclosures

All authors: No reported disclosures.

Pneumococcal biliary tract infections - How rare are they?

Pneumococcal biliary tract infections (PBTIs) were reported as rare due to the bacterium's bile solubility. The purpose of this study was to determine the occurrence and clinical characteristics of PBTIs. A retrospective case series review was conducted from January 2006 to August 2014 at a tertiary referral university hospital in Japan. Patients with a blood or bile culture positive for Streptococcus pneumoniae diagnosed with definite cholangitis or cholecystitis according to Tokyo Guideline 2013 were enrolled in this study. Data on clinical information, treatments, and outcomes were collected. During 104 months, 48 cases of positive blood cultures and 13 cases of positive bile cultures were recorded, and after excluding 43 and 5 of these, respectively, a total of 10 patients were diagnosed with PBTI. Most patients (9/10) had biliary tract problems and biliary devices in place. PBTIs were not rare; conversely, they were a relatively common cause of pneumococcal bacteremia in this center treating a high volume of biliary tract illnesses.