Comparison between IMP carbapenemase-producing Enterobacteriaceae and non-carbapenemase-producing Enterobacteriaceae: a multicentre prospective study of the clinical and molecular epidemiology of carbapenem-resistant Enterobacteriaceae.

BACKGROUND: Carbapenem-resistant Enterobacteriaceae (CRE) are classified as carbapenemase-producing Enterobacteriaceae (CPE) and non-CPE; the majority of CPE in Japan produce IMP carbapenemase. OBJECTIVES: We evaluated the clinico-epidemiological and microbiological information and effects of IMP-type carbapenemase production in CRE. METHODS: Patients with isolations of CRE (MICs of meropenem ≥2 mg/L, imipenem ≥2 mg/L or cefmetazole ≥64 mg/L) from August 2016 to March 2018 were included. Microbiological analyses and WGS were conducted and clinical parameters were compared between groups. Independent predictors for the isolation of CPE from patients were identified by logistic regression. For comparing clinical outcomes, a stabilized inverse probability weighting method was used to conduct propensity score-adjusted analysis. RESULTS: Ninety isolates (27 CPE and 63 non-CPE) were collected from 88 patients (25 CPE and 63 non-CPE). All CPE tested positive for IMP carbapenemase. Antibiotic resistance (and the presence of resistance genes) was more frequent in the CPE group than in the non-CPE group. Independent predictors for CPE isolation were residence in a nursing home or long-term care facility, longer prior length of hospital stay (LOS), use of a urinary catheter and/or nasogastric tube, dependent functional status and exposure to carbapenem. Although in-hospital and 30 day mortality rates were similar between the two groups, LOS after CRE isolation was longer in the CPE group. CONCLUSIONS: IMP-CPE were associated with prolonged hospital stays and had different clinical and microbiological characteristics compared with non-CPE. Tailored approaches are necessary for the investigational and public health reporting, and clinical and infection prevention perspectives for IMP-CPE and non-CPE.

Fatal fulminant Clostridioides difficile colitis caused by Helicobacter pylori eradication therapy; a case report.

A 74-year-old male was referred to our critical care department for refractory severe watery diarrhea with advanced leukocytosis (over 70,000/µl) after multiple administrations of eradication therapy against Helicobacter pylori (HP). He was diagnosed as having fulminant colitis due to Clostridioides difficile after antimicrobial eradication therapy. He was given intravenous metronidazole and oral vancomycin. He also received supportive therapy including continuous hemodiafiltration for severe metabolic acidosis. However, despite emergency open sigmoidectomy, he died. The C. difficile isolate recovered was PCR-ribotype 002, which was positive for toxins A and B but negative for binary toxin. HP eradication therapy for prevention of chronic gastritis and stomach cancer is now in widespread use. Although such secondary severe complications are rare, we consider it to be necessary to pay sufficient attention when administering HP eradication therapy.

Two cases with bacteremia suspected to be due to relatively rare Pseudomonas (Flavimonas) oryzihabitans.

Pseudomonas oryzihabitans (formerly Flavimonas oryzihabitans) is a glucose non-fermentative, Gram-negative bacillus which is rarely isolated from human specimens. When isolated, it is on very rare occasion as a causative pathogen of catheter-related bloodstream infection in an immunocompromised patient. Herein, we describe two hematological malignancy patients suspected to have P. oryzihabitans bacteremia. We also review cases with bacteremia due to this pathogen and its microbiological characteristics.

Outcome of corticosteroid administration in autoimmune pulmonary alveolar proteinosis: a retrospective cohort study.

BACKGROUND: Although no report has demonstrated the efficacy of corticosteroid therapy for autoimmune pulmonary alveolar proteinosis (aPAP), we sometimes encounter patients who have received this therapy for various reasons. However, as corticosteroids can suppress alveolar macrophage function, corticosteroid therapy might worsen disease severity and increase the risk of infections. METHODS: For this retrospective cohort study, we sent a screening form to 165 institutions asking for information on aPAP patients treated with corticosteroids. Of the resulting 45 patients screened, 31 were enrolled in this study. We collected demographic data and information about corticosteroid treatment period, dose, disease severity score (DSS) over the treatment period, and complications. RESULTS: DSS deteriorated during corticosteroid therapy in 23 cases (74.1 %) and the estimated overall cumulative worsening rate was 80.8 % for the total observation period. The worsening rate was significantly higher in patients treated with high-dose prednisolone (>18.9 mg/day, n = 16) than treated with low-dose prednisolone (≤18.9 mg/day, n = 15) divided by median daily dose (p < 0.02). Of patients with worsening, one died of disseminated aspergillosis and another of respiratory failure. Infections newly emerged in 6 cases during corticosteroid therapy (p < 0.05). Median serum granulocyte/macrophage colony-stimulating factor (GM-CSF) autoantibody levels were similar to previously reported data in a large cohort study. CONCLUSION: The results demonstrate that corticosteroid therapy may worsen DSS of aPAP, increasing the risk for infections.

Pirfenidone inhibits fibrocyte accumulation in the lungs in bleomycin-induced murine pulmonary fibrosis.

BACKGROUND: Bone marrow-derived fibrocytes reportedly play important roles in the pathogenesis of idiopathic pulmonary fibrosis. Pirfenidone is an anti-fibrotic agent; however, its effects on fibrocytes have not been investigated. The aim of this study was to investigate whether pirfenidone inhibits fibrocyte pool size in the lungs of bleomycin-treated mice. METHODS: Bleomycin (100 mg/kg) was infused with osmotic pumps into C57BL/6 mice, and pirfenidone (300 mg/kg/day) was orally administered daily for 2 wk. The lungs were removed, and single-cell suspensions were subjected to fluorescence-activated cell sorter (FACS) analysis to detect fibrocytes, which were defined as CD45 and collagen-I double-positive cells. Immunohistochemistry was performed on the lung specimens to quantify fibrocytes. Chemokines in the lung digests were measured with enzyme-linked immunosorbent assay. The effect of pirfenidone on alveolar macrophages was evaluated with bronchoalveolar lavage (BAL). In a therapeutic setting, pirfenidone administration was initiated 10 days after bleomycin treatment. For chemotaxis assay, lung fibrocytes were isolated with immunomagnetic selection (CD45-positive mesenchymal cells) after culture and allowed to migrate toward chemokines in the presence or absence of pirfenidone. Moreover, the effect of pirfenidone on the expression of chemokine receptors on fibrocytes was evaluated. RESULTS: Pirfenidone significantly ameliorated bleomycin-induced pulmonary fibrosis as assessed with quantitative histology and collagen measurement. Fibrocyte pool size in bleomycin-treated mice lungs was attenuated from 26.5% to 13.7% by pirfenidone on FACS analysis. This outcome was also observed in a therapeutic setting. Immunohistochemistry revealed that fibrocytes were significantly decreased by pirfenidone administration compared with those in bleomycin-treated mice (P = 0.0097). Increased chemokine (CC motif) ligand-2 (CCL2) and CCL12 production in bleomycin-treated mouse lungs was significantly attenuated by pirfenidone (P = 0.0003 and P < 0.0001, respectively). Pirfenidone also attenuated macrophage counts stimulated by bleomycin in BAL fluid. Fibrocyte migration toward CCL2 and chemokine (CC motif) receptor-2 expression on fibrocytes was significantly inhibited by pirfenidone in vitro. CONCLUSIONS: Pirfenidone attenuated the fibrocyte pool size in bleomycin-treated mouse lungs via attenuation of CCL2 and CCL12 production in vivo, and fibrocyte migration was inhibited by pirfenidone in vitro. Fibrocyte inhibition is considered a mechanism of anti-fibrotic action of pirfenidone.

Light chain (κ/λ) ratio of GM-CSF autoantibodies is associated with disease severity in autoimmune pulmonary alveolar proteinosis.

Previous studies demonstrated that antigranulocyte colony-stimulating factor autoantibody (GMAb) was consistently present in patients with autoimmune pulmonary alveolar proteinosis (aPAP), and, thus, represented candidature as a reliable diagnostic marker. However, our large cohort study suggested that the concentration of this antibody was not correlated with disease severity in patients. We found that the κ/λ ratio of GMAb was significantly correlated with the degree of hypoxemia. The proportion of λ-type GMAb per total λ-type IgG was significantly higher in severely affected patients than those in mildly affected patients, but the proportion of κ-type was unchanged. The κ/λ ratio was significantly correlated with both KL-6 and SP-D, which have been previously reported as disease severity markers. Thus, the light chain isotype usage of GMAb may not only be associated with the severity of aPAP, but may also represent a useful disease severity marker.

Descending necrotizing mediastinitis associated with Lactobacillus plantarum.

BACKGROUND: Descending necrotizing mediastinitis (DNM), a severe infection with a high fatality rate, develops in mediastinal spaces due mainly to deep cervical abscesses. The majority of causative microbes of DNM are Streptococci and oral anaerobes. DNM associated with Lactobacillus-infection is rather rare. CASE PRESENTATION: A 69-year-old male with an unremarkable past medical history was referred to our hospital for surgical resection of advanced laryngeal cancer. Full examination revealed a neck abscess and DNM with a background of untreated diabetes mellitus. Initially, he was treated with meropenem. However, Lactobacillus plantarum was isolated from surgical drainage of a mediastinal abscess. Despite using antibiotics capable of eradicating all isolates with susceptibilities not differing significantly from those of the neck and mediastinal abscesses, we attributed DNM to the L. plantarum detected only in the mediastinal abscess. After DNM treatment, he underwent total pharyngolaryngectomy with bilateral neck dissection followed by reconstruction using free jejunum. He was discharged fully recovered. CONCLUSION: We concluded that L. plantarum as the sole cause of the mediastinal abscess in the present case cannot be ruled out. As the number of immunocompromised patients increases, we should be cautious regarding this "familiar" microbe.

IgM-type GM-CSF autoantibody is etiologically a bystander but associated with IgG-type autoantibody production in autoimmune pulmonary alveolar proteinosis.

The granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibody (GMAb) is the causative agent underlying autoimmune pulmonary alveolar proteinosis (aPAP). It consists primarily of the IgG isotype. At present, information on other isotypes of the autoantibody is limited. We detected serum the IgM isotype of GMAb (IgM-GMAb) in more than 80% of patients with aPAP and 22% of healthy subjects, suggesting that a continuous antigen pressure may be present in most patients. Levels of the IgM isotype were weakly correlated with IgG-GMAb levels but not IgA-GMAb, suggesting that its production may be associated with that of IgG-GMAb. The mean binding avidity to GM-CSF of the IgM isotype was 100-fold lower than the IgG-GMAb isotype, whereas the IC(50) value for neutralizing capacity was 20,000-fold higher than that of IgG-GMAb, indicating that IgM-GMAb is only a very weak neutralizer of GM-CSF. In bronchoalveolar lavage fluid from nine patients, IgG-GMAb was consistently detected, but IgM-GMAb was under the detection limit in most patients, confirming that IgM-GMAb is functionally a bystander in the pathogenesis of aPAP. It rather may be involved in the mechanism for development of IgG-GMAb in vivo.

First report of infectious pericarditis due to Bordetella holmesii in an adult patient with malignant lymphoma.

Bordetella holmesii is a fastidious Gram-negative rod first identified in 1995. Though rare, it is isolated mainly in immunocompromised and asplenic hosts and is associated with bacteremia, pertussis-like respiratory tract infection, and endocarditis. Herein, we describe a unique B. holmesii infectious pericarditis patient with malignant lymphoma.

Adult-onset hereditary pulmonary alveolar proteinosis caused by a single-base deletion in CSF2RB.

BACKGROUND: Disruption of granulocyte/macrophage colony-stimulating factor (GM-CSF) signalling causes pulmonary alveolar proteinosis (PAP). Rarely, genetic defects in neonatal or infant-onset PAP have been identified in CSF2RA. However, no report has clearly identified any function-associated genetic defect in CSF2RB. METHODS AND RESULTS: The patient was diagnosed with PAP at the age of 36 and developed respiratory failure. She was negative for GM-CSF autoantibody and had no underlying disease. Signalling and genetic defects in GM-CSF receptor were screened. GM-CSF-stimulated STAT5 phosphorylation was not observed and GM-CSF-Rßc expression was defective in the patient's blood cells. Genetic screening revealed a homozygous, single-base deletion at nt 631 in exon 6 of CSF2RB on chromosome 22, which caused reductions in GM-CSF dependent signalling and function. Both parents, who were second cousins, showed no pulmonary symptoms, and had normal GM-CSF-signalling, but had a CSF2RB allele with the identical deletion, indicating that the mutant allele may give rise to PAP in an autosomal recessive manner. CONCLUSIONS: This is the first report identifying a genetic defect in CSF2RB that causes deficiency of GM-CSF-Rßc expression and impaired signalling downstream. These results suggested that GM-CSF signalling was compensated by other signalling pathways, leading to adult-onset PAP.

A case of streptococcal toxic shock syndrome due to Group G streptococci identified as Streptococcus dysgalactiae subsp. equisimilis.

A 79-year-old man with a 3-month history of lymphedema of the lower limbs, and diabetes mellitus, was admitted to our hospital for suspected deep venous thrombosis. Several hours after admission, leg pain and purpura-like skin color appeared. On the 2nd hospital day, he was referred to our department for possible acute occlusive peripheral artery disease (PAD) and skin necrosis with blisters; however, computed tomography with contrast showed no occlusive lesions. He had already developed shock and necrotizing deep soft-tissue infections of the left lower leg. Laboratory findings revealed renal dysfunction and coagulation system collapse. Soon after PAD was ruled out, clinical findings suggested necrotizing deep soft-tissue infections, shock state, disseminated intravascular coagulation, and multiple organ failure. These symptoms led to a high suspicion of the well-recognized streptococcal toxic shock syndrome (STSS). With a high suspicion of STSS, we detected Group G ß-hemolytic streptococci (GGS) from samples aspirated from the leg bullae, and the species was identified as Streptococcus dysgalactiae subsp. equisimilis (SDSE) by 16S-ribosomal RNA sequencing. However, unfortunately, surgical debridement was impossible due to the broad area of skin change. Despite adequate antimicrobial therapy and intensive care, the patient died on the 3rd hospital day. The M-protein gene (emm) typing of the isolated SDSE was revealed to be stG6792. This type of SDSE is the most frequent cause of STSS due to GGS in Japan. We consider it to be crucial to rapidly distinguish STSS from acute occlusive PAD to achieve life-saving interventions in patients with severe soft-tissue infections.

Acute Kidney Injury in Non-Intensive Care and Intensive Care Patients Treated with Vancomycin and Piperacillin-Tazobactam.

BACKGROUND: We investigated the incidence of acute kidney injury (AKI) and risk factors associated with vancomycin (VAN) and piperacillin-tazobactam (TZP) combination therapy in non-intensive care unit (ICU) and ICU settings. METHODS: In this single-center retrospective cohort study, adults who received VAN for ≥48 h during the period from 1 January 2016 through 31 December 2017 were included. The primary endpoint was incidence of AKI. RESULTS: Data from 593 adults were analyzed. The incidence of AKI was 10.6% overall, 8.0% in the non-TZP group, and 19.8% in the TZP group. In univariate analysis, the odds ratio (OR) for AKI was higher in the TZP group than in the non-TZP group (2.84, 95% CI = 1.64-4.90). In both the non-ICU and ICU settings, the OR for AKI was higher in the TZP group than in the non-TZP group (non-ICU: OR = 3.04, 95% CI = 1.52-6.09; ICU: OR = 2.51, 95% CI = 1.03-6.08). Furthermore, in propensity score analysis, the OR for AKI was higher in the TZP group than in the non-TZP group (OR = 2.81, 95% CI = 1.52-5.17). In both the non-ICU and ICU settings, the OR for AKI was higher in the TZP group than in the non-TZP group (non-ICU: OR = 2.57, 95% CI = 1.17-5.64; ICU: OR = 3.51, 95% CI = 1.05-11.6). CONCLUSIONS: Combined use of TZP in patients receiving VAN increased AKI incidence in non-ICU and ICU settings.

[A case of suspected idiopathic pulmonary upper lobe fibrosis (Amitani disease) with acute exacerbation].

An 82-year old man was admitted to our hospital for evaluation of progressive general malaise. He had previously been in good health. His chest roentgenogram showed reticular shadows and we suspected interstitial lung disease. On admission, his roentgenographic images showed deterioration compared with previous images. Acute lung injury was diagnosed by transbronchial lung biopsy, and steroid administration was started. He initially responded to treatment, but bilateral spontaneous pneumothorax occurred. Despite treatment, he died of respiratory failure. Amitani disease (idiopathic pulmonary upper lobe fibrosis) was suspected based on postmortem pathology, but his lung parenchyma was poor due to the presence of changes producing diffuse alveolar damage. We report and discuss this case because there are apparently no previous similar cases.

Infective endocarditis caused by Cardiobacterium valvarum.

We report a case with infective endocarditis (IE) due to Cardiobacterium valvarum . The patient was a 57-year-old male, who was referred to our hospital based on suspected IE detected by transthoracic echocardiography at a neighbourhood clinic. Three sets of blood cultures obtained on admission yielded positive results, and revealed rather slender and linear Gram-negative bacilli with a rosette formation that dyed minimally, with a pale white appearance. Although no isolates were identified by conventional methods, C. valvarum was ultimately identified by 16 S ribosomal RNA genotyping. HACEK group strains are difficult to identify by conventional methods. Therefore, if Gram-negative bacilli are isolated from IE patients, 16 S ribosomal RNA genotyping will be necessary. Furthermore, IE due to C. valvarum is very rare. We thus discuss our case in comparison with previous reports.

Memory B cell pool of autoimmune pulmonary alveolar proteinosis patients contains higher frequency of GM-CSF autoreactive B cells than healthy subjects.

The IgG-type neutralizing GM-CSF autoantibody (GMAb) is known to be the causative agent for autoimmune pulmonary alveolar proteinosis (APAP). Previous studies report that serum levels of IgG-GMAb are approximately 50-fold higher in APAP patients than in healthy subjects (HS). Serum levels of IgM-GMAb are also higher in APAP patients than in HS, but this has been assumed to be an etiological bystander. However, the mechanism for the excessive production of IgG-GMAb in APAP remains unclear. To investigate this, we detected putative GMAb-producing B cells (PGMPB) by inoculated B cells from the peripheral blood of APAP patients, HS, and umbilical cord blood mononuclear cells (UCBMNs) with Epstein-Barr virus. Both ELISA and ELISPOT assays showed that IgM-type GMAb was consistently and frequently present in all three groups, whereas IgG-type GMAb was high only in APAP patients, in whom it was exclusively produced in memory B cells and not in naive B cells. Since PGMPB in UCBMNs produced IgM-GMAb, but not IgG-GMAb, to the same extent as in HS and APAP patients, most IgM-GMAb reacted with GM-CSF in a non-specific manner. The memory B cell pool of APAP patients contain higher frequency of PGMPB than that of healthy subjects.

Transbronchial biopsy is clinically useful in classifying patients with interstitial pneumonia associated with polymyositis and dermatomyositis.

BACKGROUND AND OBJECTIVE: The histological type of intraluminal fibrosis is an important prognostic factor for interstitial pneumonia. We therefore examined whether transbronchial lung biopsy (TBLB) specimens are useful for predicting the clinical course and prognosis of patients with interstitial pneumonia associated with polymyositis and dermatomyositis (PM/DM), with particular attention to the different types of intraluminal fibrosis. METHODS: Twenty-five cases of interstitial pneumonia associated with PM/DM were classified according to the pattern of intraluminal fibrosis as assessed by TBLB, and the clinical course and response to treatment were compared. Interstitial fibrosis was evaluated by sequential thin-section CT scans. RESULTS: In 19 of 25 (76%) cases, there was sufficient intraluminal fibrosis to perform an evaluation. Intraluminal fibrosis was classified as bud (polyp) type or mural incorporation type (either alone or mixed with bud type). The bud type was seen in five cases and these improved following treatment with corticosteroids only. The mural incorporation type was seen in 14 cases. In 11 of these 14 cases, progressive long-term fibrosis developed and four cases were fatal, in spite of corticosteroid and immunosuppressive therapy. The response to drugs (P < 0.01) and survival (P < 0.05) were significantly greater in patients with bud-type than mural incorporation-type intraluminal fibrosis. CONCLUSIONS: Classification of the pattern of intraluminal fibrosis as assessed by TBLB is useful for predicting the response to treatment, clinical course and prognosis of interstitial pneumonia associated with PM/DM.

Kodamaea ohmeri fungemia in severe burn: Case study and literature review.

Kodamaea ohmeri is a relatively rare yeast isolated form clinical specimens, and it is known to be a causative fungus of severe invasive infectious diseases in immunocompromised hosts. Herein, we describe fungemia due to K. ohmeri in a patient with a severe extended burn. The isolate was obtained from not only blood specimens but also skin lesions. We should be aware of risk for fungemia including K. ohmeri in case of severe burn.

Reduced incidence of lung cancer in patients with idiopathic pulmonary fibrosis treated with pirfenidone.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a disease with a worse prognosis than some types of cancer. In patients with IPF, lung cancer is critical because of the associated high mortality rate from its progression and fatal complications from anticancer treatments. Therefore, preventing lung cancer in patients with IPF is primordial. Pirfenidone is an anti-fibrotic agent that reduces the decline in forced vital capacity. This study aimed to assess the effect of pirfenidone in the development of lung cancer in patients with IPF. METHODS: Data from 261 patients with IPF with and without pirfenidone were retrospectively reviewed, and the incidence of lung cancer was analyzed. RESULTS: In the pirfenidone group, the incidence of lung cancer was significantly lower than in the non-pirfenidone group (2.4% vs. 22.0%, P < 0.0001). Multivariate Cox proportional hazards regression analysis demonstrated that pirfenidone decreased the risk of lung cancer (hazard ratio, 0.11; 95% confidence interval, 0.03 to 0.46; P = 0.003), whereas coexisting emphysema increased the incidence of lung cancer (hazard ratio, 3.22; 95% confidence interval, 1.35 to 7.70; P = 0.009). CONCLUSIONS: Pirfenidone might correlate with a decreased risk of lung cancer in patients with IPF. However, no definite conclusion can be drawn from this retrospective study, and a multicenter, prospective cohort study is still warranted to confirm the effect of pirfenidone on lung cancer in patients with IPF.

[A case of secondary pulmonary cryptococcosis with pleural effusion involving type 1 allergy].

A 69-year-old man who had been followed for pneumoconiosis complained of dyspnea with effort. He was hospitalized because chest roentogenography showed pleural effusion. Further examination of this pleural effusion revealed an eosinophilic cell population and with a varied appearance. First, we suspected tuberculous pleuritis from the characteristics of the pleural effusion, but we could not demonstrate the existence of any acid-fast bacilli. During diagnostic studies, the patient's respiratory status gradually worsened, making it impossible to obtain essential findings. We initiated steroid administration as an antidote to progressive respiratory failure, and carried out bronchoscopy; As a result, we diagnosed secondary pulmonary cryptococcosis from bronchoalveolar lavarge and transbronchial lung biopsy. Pulmonary cryptococcosis with pleural effusion is rare, and this may be the first report of a case involving a type 1 allergy. We speculate that immunological dysfunction contributed to disease progression in this case.

Neck abscess due to Salmonella Choleraesuis: case study and literature review.

Introduction. We herein describe a case with a neck abscess due to non-typhoidal Salmonella (NTS). NTS habitually reside in our environment and colonize all animals including mammals. Colonizations of pigs, chickens, cows and sheep are important because food poisoning episodes in human are often associated with meat. Extra-intestinal infection due to NTS has numerous presentations and complications, with aortic aneurysms being common. Case presentation. A 26-year-old Japanese male complaining of left-sided neck swelling was referred to our hospital for a suspected deep neck abscess. An enhanced computed tomography scan of the neck revealed a low density lesion in the left-sided deep neck area, and consequently the patient underwent urgent incision and drainage. After this urgent operation, Salmonella Choleraesuis was isolated from a greyish-white abscess. The patient ultimately recovered with antimicrobial administration, though re-incision for lymphadenectomy was necessary. The neck abscess may have developed because he had eaten raw meat. Furthermore, untreated diabetes mellitus was diagnosed at presentation. Conclusion.Salmonella enterica serovar Choleraesuis infections are rare in Japan. NTS are generally recognized as important pathogens in food poisoning globally, and attention is required to avoid the development of extra-intestinal infections. In Japan, the increasing lifestyle diversity in recent years highlights the importance of recognizing rare infections.