Empyema necessitans caused by methicillin-resistant Staphylococcus aureus: a case report and literature review.

BACKGROUND: Empyema necessitans (EN) is a rare condition characterized by pleural infection with pus spreading into adjacent soft tissues. Although Mycobacterium tuberculosis and Actinomyces israelii are common causative agents, methicillin-resistant Staphylococcus aureus (MRSA) is relatively rare, but it is associated with high mortality in empyema cases. We aimed to report a unique case of EN caused by MRSA and present a literature review to better understand this rare condition. CASE PRESENTATION: A 69-year-old man with a history of right ureteral stone presented with fever and left anterior thoracic pain. A physical examination revealed redness and swelling in the left thoracic region. Imaging studies confirmed EN with fluid accumulation around the sternocostal joint of the left first rib. MRSA was identified from blood and pleural fluid cultures. The patient received antimicrobial therapy, and a chest tube was inserted for drainage. Despite initial improvement, vertebral osteomyelitis was diagnosed on day 17. The antimicrobials were subsequently terminated after 6 weeks, but vertebral osteomyelitis recurred, and treatment was resumed and completed on day 215. CONCLUSION: EN caused by MRSA is rare, and the literature review revealed 14 cases from human sources. Positive blood cultures were observed in 40% of cases, and metastatic infections were present in 30% of cases. Osteomyelitis was the most common type of metastatic lesion. All the patients underwent drainage. Patients with MRSA-associated EN frequently develop disseminated lesions and should therefore be carefully examined. Moreover, appropriate treatment with antibiotics and drainage is necessary for a good prognosis. Although the prognosis appeared to be favorable in our review, publication bias and treatment challenges for metastatic infections should be considered.

Retrospective Study on Penicillin Allergy Delabeling and Evaluation of an Antibiotic Allergy Assessment Tool.

BACKGROUND: It has been reported that 95% of patients labeled as penicillin-allergic may be mislabeled. However, the process of delabeling has not advanced due to a shortage of allergy specialists capable of conducting accurate assessments. To address this issue, The Antibiotics Allergy Assessment Tool (AAAT) has been proposed as a tool to evaluate patients who can be delabeled by non-specialists. OBJECTIVE: This study aims to identify patients who can be delabeled and to evaluate patients who are likely to be delabeled using AAAT. METHODS: Patients admitted to the hospital between January 1, 2017, and December 31, 2021, with documented penicillin allergy labels were included in the study. Patients who demonstrated tolerance to labeled antibiotics or were labeled without explicit allergy declarations were defined as delabeling. Subsequently, patients who did not meet the criteria for delabeling were evaluated for their potential to be delabeled using the AAAT, retrospectively. RESULTS: 530 patients were selected, of which 62 (11.7%) were delabeled. The AAAT evaluation of the remaining patients indicated that at least an additional 137 (25.8%) patients could potentially be delabeled. CONCLUSION: The use of AAAT demonstrated the potential to delabel approximately third as many patients without the need for specialist evaluation. To promote broader delabeling efforts in the future, prospective studies should investigate the safety and effectiveness of evaluation tools such as the AAAT.

Tocilizumab in combination with standard of care in patients with severe COVID-19 pneumonia: efficacy and safety from a phase 3 clinical trial in Japan.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is characterized by high interleukin-6 levels. Clinical data supporting tocilizumab, a monoclonal antibody that targets interleukin-6 receptor-alpha, for treating Japanese patients with severe COVID-19 pneumonia are needed. METHODS: This single-arm phase 3 study investigated tocilizumab (8 mg/kg) plus standard of care (SOC) in Japanese patients hospitalized with severe COVID-19 pneumonia. Clinical status was assessed using a 7-category ordinal scale on day 28 (primary endpoint) and day 14 (secondary endpoint). Other secondary endpoints were time to improvement (≥2 category improvement) and time to hospital discharge. Safety was assessed as the incidence of adverse events (AEs). RESULTS: Among 48 patients enrolled, 44 (91.7%) scored ≥3 on the 7-category ordinal scale at baseline. At day 28, 35 patients (72.9%) scored 1 and 5 (10.4%) scored 7 on the 7-category ordinal scale; 36 (75.0%, 95% confidence interval [CI]: 60.40-86.36%) and 39 (81.3%, 95% CI: 67.37-91.05%) patients achieved ≥2- and ≥1-category improvement, respectively; 6 patients (12.5%, 95% CI: 4.73-25.25%) demonstrated ≥1-category worsening. At day 14, 25 (52.1%, 95% CI: 37.19-66.71%) and 33 patients (68.8%, 95% CI: 53.75-81.34%) achieved ≥2- and ≥1-category improvement, respectively; 5 patients (10.4%, 95% CI: 3.47-22.66%) demonstrated ≥1-category worsening. Median times (95% CI) to improvement and hospital discharge were 11 (9-15) and 15 (11-18) days, respectively. Forty patients (83.3%) experienced AEs; the incidence of ≥grade 3 AEs was 25%. CONCLUSION: Tocilizumab plus SOC may provide improved clinical status in Japanese patients with severe COVID-19 pneumonia; no new safety signals were identified.

Cost-effectiveness analysis of CTZ/TAZ for the treatment of ventilated hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia in Japan.

BACKGROUND: Resistant bacterial infections, particularly those caused by gram-negative pathogens, are associated with high mortality and economic burdens. Ceftolozane/tazobactam demonstrated efficacy comparable to meropenem in patients with ventilated hospital-acquired bacterial pneumonia in the ASPECT-NP study. One cost-effectiveness analysis in the United States revealed that ceftolozane/tazobactam was cost effective, but no Japanese studies have been conducted. Therefore, the objective of this study was to assess the cost-effectiveness of ceftolozane/tazobactam compared to meropenem for patients with ventilated hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia from a health care payer perspective. METHODS: A hybrid decision-tree Markov decision-analytic model with a 5-year time horizon were developed to estimate costs and quality-adjusted life-years and to calculate the incremental cost-effectiveness ratio associated with ceftolozane/tazobactam and meropenem in the treatment of patients with ventilated hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia. Clinical outcomes were based on the ASPECT-NP study, costs were based on the national fee schedule of 2022, and utilities were based on published data. One-way sensitivity analysis and probabilistic sensitivity analysis were also conducted to assess the robustness of our modeled estimates. RESULTS: According to our base-case analysis, compared with meropenem, ceftolozane/tazobactam increased the total costs by 424,731.22 yen (£2,626.96) and increased the quality-adjusted life-years by 0.17, resulting in an incremental cost-effectiveness ratio of 2,548,738 yen (£15,763.94) per quality-adjusted life-year gained for ceftolozane/tazobactam compared with meropenem. One-way sensitivity analysis showed that although the incremental cost-effectiveness ratio remained below 5,000,000 yen (£30,925) for most of the parameters, the incremental net monetary benefit may have been less than 0 depending on the treatment efficacy outcome, especially the cure rate and mortality rate for MEPM and mortality rate for CTZ/TAZ. 53.4% of the PSA simulations demonstrated that CTZ/TAZ was more cost-effective than MEPM was. CONCLUSION: Although incremental cost-effectiveness ratio was below ï¿¥5,000,000 in base-case analysis, whether ceftolozane/tazobactam is a cost-effective alternative to meropenem for ventilated hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia in Japan remains uncertain. Future research should examine the unobserved heterogeneity across patient subgroups and decision-making settings, to characterise decision uncertainty and its consequences so as to assess whether additional research is required.

First case report of splenomegaly with splenic infarction due to aortic graft infection.

BACKGROUND: Diagnosis of aortic graft infections (AGI) is challenging. Here, we report a case of AGI with splenomegaly and splenic infarction. CASE PRESENTATION: A 46-year-old man who underwent total arch replacement for Stanford type A acute aortic dissection one year prior presented to our department with fever, night sweat, and a 20-kg weight loss over several months. Contrast-enhanced computed tomography (CT) revealed splenic infarction with splenomegaly, fluid collection, and thrombus around the stent graft. Positron emission tomography-CT (PET-CT) revealed abnormal 18F-fluorodeoxyglucose uptake in the stent graft and spleen. Transesophageal echocardiography revealed no vegetations. The patient was diagnosed with an AGI and underwent graft replacement. Blood and tissue cultures in the stent graft yielded Enterococcus faecalis. After the surgery, the patient was successfully treated with antibiotics. CONCLUSIONS: Splenic infarction and splenomegaly are the clinical findings of endocarditis but are rare in graft infection. These findings could be helpful to diagnose graft infections, which is often challenging.

Increased human immunodeficiency virus viral load with cerebral infarction due to varicella zoster virus vasculopathy on treatment with bictegravir/emtricitabine/tenofovir alafenamide suspension: a case report and literature review.

BACKGROUND: Varicella-Zoster virus (VZV) vasculopathy occasionally occurs in immunocompromised patients and is difficult to treat. The risk factor and optimal therapy remain unclear. Patients with human immunodeficiency virus (HIV) and dysphagia or difficulty in oral intake receive antiretroviral therapy (ART) suspension. However, there remains little evidence regarding ART suspension. CASE PRESENTATION: We experienced a case of a 55-year-old man diagnosed with HIV and severe multiple cerebral infarctions due to VZV vasculopathy. We started on bictegravir/tenofovir alafenamide/emtricitabine (BIC/TAF/FTC) and acyclovir (ACV), and prednisone. He was started on BIC/TAF/FTC suspension because of deteriorated swallowing. The HIV viral load was increased; however, no drug-resistance genes were detected. We successfully treated him with doltegravir/abacavir/lamibudine suspension. We performed two literature reviews of the administration of BIC/TAF/3TC suspension and VZV vasculopathy in patients with HIV. Three cases of BIC/TAF/3TC suspension were considered treatment failures. Recent history of VZV infection and a CD4 count under 200 µL may be risk factors for VZV vasculopathy. The effective treatment may be using steroid and ACV; however, treatment duration could differ. CONCLUSIONS: BIC/TAF/FTC suspension administration may be unstable, and treating ACV and steroid may be optimal therapy for VZV vasculopathy; however, the evidence level is low.

Probiotic-related Clostridium butyricum bacteremia: a case report and literature review.

We report three cases of Clostridium butyricum bacteremia associated with taking C. butyricum-related probiotics. We performed a literature review and found 11 cases of C. butyricum bacteremia including our cases. Nine cases related to probiotics. We should consider that probiotics may infect clinically unstable patients.

In Vitro Activity and Clinical Efficacy of Faropenem against Third-Generation Cephalosporin-Resistant Escherichia coli and Klebsiella pneumoniae.

Faropenem (FRPM) is active against extended-spectrum ß-lactamase (ESBL)-producing Enterobacterales, but evidence for its efficacy is lacking. This study determined the correlation between the susceptibility by disk diffusion method and the MIC of FRPM for third-generation cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae, and the effectiveness of FRPM for the treatment of urinary tract infection (UTI) caused by these two bacteria in a retrospective cohort analysis. Of the 48 third-generation cephalosporin-resistant clinical isolates tested, 44 isolates produced ESBL, and 8 isolates produced AmpC, including 4 isolates produced both ESBL and AmpC. Thirty-seven isolates had an FRPM MIC of ≤1 mg/L, and seven had an FRPM MIC of 2 mg/L. An FRPM MIC of >2 mg/L was observed with four isolates. In a retrospective cohort analysis, 63 patients with UTI treated with FRPM were identified. All isolates of ESBL-producing E. coli (n = 54) and K. pneumoniae (n = 9) treated with FRPM showed disk diffusion zone diameters larger than 16.0 mm (estimated MIC, 2.2 mg/L). All patients completed the scheduled treatment courses with FRPM, but 28- and 90-day relapses happened in 10 patients (16%) and 16 patients (25%), respectively. No significant risk factors for the 28- and 90-day relapses were found. FRPM can be used according to disk diffusion susceptibility testing in UTI. Further investigations are necessary to assess the clinical breakpoint of FRPM for ESBL-producing Enterobacterales and the candidates most likely to benefit from using FRPM.

Multidisciplinary management of disseminated Exophiala dermatitidis mycosis in an infant with mixed phenotype acute leukemia: a case report.

BACKGROUND: Exophiala dermatitidis is a dematiaceous fungus isolated from various environmental sources. Systemic E. dermatitidis infections can lead to fatal outcomes, and treatment has not yet been standardized. Although E. dermatitidis is also known to cause cutaneous infection, it has not been previously reported to appear as ecthyma gangrenosum (EG), an uncommon cutaneous lesion in neutropenic patients that is mainly caused by Pseudomonas aeruginosa. CASE PRESENTATION: A 2-month-old male infant with mixed-phenotype acute leukemia presented with prolonged fever unresponsive to antibacterial and antifungal agents during myelosuppression due to remission induction therapy. He also presented with skin lesions on the left wrist and left lower quadrant of the abdomen. The abdominal lesion gradually turned black and necrotic, which was consistent with the findings of the EG. E. dermatitidis was isolated from the blood, stool, wrist skin, and endotracheal aspirate. During hematopoietic recovery, consolidation in both lungs was evident. Multiagent antifungal treatment failed to eliminate E. dermatitidis from blood. In order to salvage the central venous catheter, ethanol lock therapy (ELT) was adopted, following which the blood culture became negative. The abdominal lesion that evolved as a necrotic mass connecting the small intestine and subcutaneous tissue adjacent to the skin was surgically resected. After these interventions, the general condition improved. CONCLUSION: Disseminated E. dermatitidis mycosis in the neutropenic infant was successfully managed with a multidisciplinary treatment consisting of multiagent antifungal treatment, ELT, and surgery.

Acute heart failure associated with toxic shock syndrome due to methicillin-susceptible Staphylococcus aureus during the postpartum period: case report and systematic literature review.

BACKGROUND: Toxic shock syndrome (TSS) caused by Staphylococcus aureus in the postpartum period is a rare but life-threatening disease. We present a case of acute heart failure as the initial presentation of TSS due to methicillin-susceptible Staphylococcus aureus (MSSA) and describe its clinical characteristics with a systematic literature review. CASE PRESENTATION: A 34-year-old woman, 8 days after a normal vaginal delivery presented to our hospital with dyspnea and fever. She had jugular venous distension, bilateral leg edema, and erythema. Laboratory examinations revealed elevated NT-pro-BNP level of 3,233 pg/mL. Transthoracic echocardiography showed elevated tricuspid regurgitation peak gradient, with decreased respiratory variability of the inferior vena cava diameter and bilateral pleural effusions. The patient was hospitalized with suspicion of congestive heart failure. MSSA positive for toxic shock syndrome exotoxin-1 was detected in the culture of the perineal incision wound, and we diagnosed TSS caused by MSSA. Intravenous diuretics were administered, along with eventual cefazolin plus clindamycin. After 2 weeks of antimicrobial therapy, the patient showed improvement and was discharged. No recurrence was observed at the 24-month follow-up. CONCLUSION: This is a rare case report of acute heart failure being the initial manifestation of TSS due to MSSA in the postpartum period. Clinicians should consider TSS as a possibility in postpartum patients with acute heart failure. This systematic review provides insights into its clinical features, treatment regimens, and prognosis of TSS by S. aureus in the postpartum period. TSS requires an appropriate, prompt diagnosis, because delayed treatment can be fatal.

SEASON GAP score: A predictor of Clostridioides difficile infection among patients with tube feeding.

INTRODUCTION: Clostridioides difficile infection (CDI) is an important community- and hospital-acquired infection. Patients receiving tube feeding often have diarrhoea, and it is still unclear whether the traditional criteria for submitting samples for Clostridioides difficile (CD) testing as determined by the frequency of the diarrhoea apply to these patients. METHODS: We conducted a retrospective study comparing the clinical features of tube-fed inpatients with suspected CDI, with CDI, and those without CDI admitted between 2004 and 2020. Univariate associations were assessed using the chi-square test, Fisher's exact test, or student's t-test, and multivariate analysis was conducted using logistic regression analysis. RESULTS: Among 805 tube-fed inpatients with and suspected CDI, 163 (20.2%) had CDI and 642 (79.8%) did not. The following seven predictors, independently associated with CDI, were used to develop the SEASON GAP score: male (Sex) (1 point), Emaciation (1 point), days from Admission to testing ≥21 days (2 points), Stool frequency/day ≥5 times (1 point), seasON (summer: 2 points, spring and winter: 1 point), GAstrostomy (2 points), and no prior Proton pump inhibitor use (1 point). In a receiver operating characteristic curve, the area under the curve was 0.77 (95% confidence interval: 0.73-0.80). The optimal cut-off point was 3.5. A score of ≤3 had a sensitivity, specificity, and negative predictive value of 81%, 60%, and 93%, respectively. CONCLUSIONS: The SEASON GAP score is useful in ruling out CDI in patients with tube feeding, thus reducing unnecessary CD testing and antimicrobial use.

Predicting bacteremia caused by Streptococcus anginosus group: A new scoring method.

BACKGROUND: Viridans group streptococci (VGS) are the most common causative organisms of infective endocarditis. Among VGS, the Streptococcus anginosus group (SAG) is often associated with abscess formation, and delayed diagnosis leads to increased morbidity and mortality. This study aims to examine the factors associated with SAG bacteremia and develop a predictive scoring method. METHODS: This single-center retrospective case-control study of patients with VGS bacteremia compared the background and clinical characteristics between the SAG and non-SAG groups. The univariate analysis used the χ2 test and t-test. The multivariate analysis was conducted using logistic regression. RESULTS: Out of 161 patients, 95 had SAG and 66 had non-SAG bacteremia. Age >63 years: 2 points (odds ratio [OR] = 3.52, 95% confidence interval [CI]: 1.64-7.54); solid tumor: 2 points (OR = 4.44, 95% CI: 1.42-6.77); C-reactive protein >7.61 mg/dL: 3 points (OR = 5.40, 95% CI: 2.49-11.72), and white blood cell count >8550/µL: 2 points (OR = 2.76, 95% CI: 1.29-2.91) were found to be independently associated with SAG bacteremia. After totaling the above variables and adding 1 point for diabetes mellitus, the area under the receiver operating curve was 0.81 (95% CI: 0.74-0.88). The sensitivity and specificity were 51% and 88%, respectively, at a cut-off of 6 points. CONCLUSIONS: In patients with VGS bacteremia, a score of 6 points or higher using this method predicts SAG with high specificity.

Penicillin- and third-generation cephalosporin-resistant strains of Streptococcus pneumoniae meningitis: Case report and literature review.

BACKGROUND: Treatment of patients with penicillin-resistant S. pneumoniae (PRSP) is complicated because of the relatively poor blood-brain barrier penetration of effective antimicrobials. Our case: A previously healthy 70-year-old woman, a traveler from China to Japan, was admitted to our hospital with fever and loss of consciousness. She has no history of pneumococcal vaccination. She was diagnosed with bacterial meningitis due to penicillin-and third-generation cephalosporin-resistant strains of S. pneumoniae. The patient was successfully treated with a combination therapy of vancomycin (VCM) and levofloxacin (LVFX) and recovered without any neurological sequelae. As the treatment of penicillin-and third-generation cephalosporin-resistant strains of S. pneumoniae meningitis remains unclear, we conducted a review of the reported cases of meningitis caused by penicillin- and cephalosporin-resistant S. pneumoniae. METHOD: We performed a search using the keywords "penicillin-resistant Streptococcus pneumoniae," "meningitis," and "pneumococcal meningitis". We searched the electronic databases PubMed, Embase, and Ichushi from their inception to March 2020. Subsequently, two authors independently reviewed the resulting database records, retrieved full texts for eligibility assessment, and extracted data from these cases. RESULT: We identified 18 papers describing thirty-five cases of penicillin- and cephalosporin-resistant S. pneumoniae meningitis including our case. The patient's characteristics were; median age: 50 years, men:50%, 85% of cases received combination regimens of antibiotics: Ceftroriaxone (CTRX) plus VCM (20 cases), CTRX plus VCM plus rifampicin (RFP) (two cases), CTRX plus linezolid (one case), fluoroquinolones (two cases), carbapenems (six cases), Thirty-five percent received steroids. Twenty-four percent of patients died. Twenty-six percent of patients complicated neurological sequalae. CONCLUSION: Combination therapy including VCM plus LVFX could be a treatment option.

Enterococcus hirae bacteremia associated with acute pyelonephritis in a patient with alcoholic cirrhosis: a case report and literature review.

BACKGROUND: Infections caused by Enterococcus hirae are common in animals, with instances of transmission to humans being rare. Further, few cases have been reported in humans because of the difficulty in identifying the bacteria. Herein, we report a case of pyelonephritis caused by E. hirae bacteremia and conduct a literature review on E. hirae bacteremia. CASE PRESENTATION: A 57-year-old male patient with alcoholic cirrhosis and neurogenic bladder presented with fever and chills that had persisted for 3 days. Physical examination revealed tenderness of the right costovertebral angle. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) of the patient's blood and urine samples revealed the presence of E. hirae, and pyelonephritis was diagnosed. The patient was treated successfully with intravenous ampicillin followed by oral linezolid for a total of three weeks. CONCLUSION: The literature review we conducted revealed that E. hirae bacteremia is frequently reported in urinary tract infections, biliary tract infections, and infective endocarditis and is more likely to occur in patients with diabetes, liver cirrhosis, and chronic kidney disease. However, mortality is not common because of the high antimicrobial susceptibility of E. hirae. With the advancements in MALDI-TOF MS, the number of reports of E. hirae infections has also increased, and clinicians need to consider E. hirae as a possible causative pathogen of urinary tract infections in patients with known risk factors.

Clinical presentation and outcomes of non-typhoidal Salmonella infections in patients with cancer.

BACKGROUND: Non-typhoidal Salmonella (NTS) infection is thought to be more severe in cancer patients, but this has not been studied since the development of new cancer therapies, increasing antibiotic resistance and the introduction of new antibiotics. We sought to describe the demographic characteristics, microbiological findings, clinical manifestations, and outcomes of NTS infections in cancer patients at our institution. METHODS: We reviewed microbiology laboratory records and identified patients who had cancer and from whom NTS organisms were recovered between January 1, 2000 and December 31, 2013, at a comprehensive cancer center in Houston, Texas. Descriptive statistics were used to summarize patient characteristics, clinical presentation and outcomes. RESULTS: We identified 110 isolates from 82 patients with 88 episodes of NTS infection (including five relapses [6%] in four patients, and two consecutive episodes in one patient). Fifty-five patients (67%) had hematologic malignancies. Most NTS isolates were susceptible to the commonly prescribed antimicrobials. Sixty-nine percent of patients had sepsis and one-third had severe sepsis or septic shock. Gastroenteritis, bacteremia, or both were present in 69% of patients, and the rest had focal infection. Mortality at 30 days was low (8%). Relapses occurred only in patients receiving ≤ 10 days of antibiotic therapy. CONCLUSIONS: NTS affects predominantly patients with hematologic malignancies, followed by gastrointestinal and genitourinary cancers. Invasive disease, sepsis, and septic shock are common presentations among admitted patients. Antimicrobial prophylaxis may not prevent NTS infection. Thirty-day mortality and attributable mortality rates were low in our series compared to older case series. Early appropriate antibiotic therapy may have had a role in decreasing mortality. Relapses occurred in patients receiving ≤ 10 days of therapy, suggesting the need for longer duration of antibiotic therapy in cancer patients with uncomplicated NTS infections.

Campylobacter fetus bacteremia and meningitis in an acute lymphoblastic leukemia patient undergoing maintenance therapy: a case report.

BACKGROUND: Campylobacter fetus is an uncommon Campylobacter species, and its infections mainly cause infective endocarditis, aortic aneurysm, and meningitis rather than enteritis. It is more likely to be detected in blood than Campylobacter jejuni or Campylobacter coli, specifically reported in 53% of patients. In our case, C. fetus was detected in both blood and cerebrospinal fluid (CSF) cultures. CASE PRESENTATION: A 33-year-old woman, who was on maintenance chemotherapy for acute lymphoblastic leukemia (ALL), presented to our clinic with chief complaints of severe headache and nausea. Blood and CSF cultures revealed C. fetus. We administrated meropenem 2 g intravenously (IV) every 8 h for 3 weeks, and she was discharged without neurological sequelae. CONCLUSION: We encountered a case of C. fetus meningitis without gastrointestinal symptoms, neck stiffness or jolt accentuation in a patient with ALL. Undercooked beef was considered the source of C. fetus infection in this case, suggesting that the need for a neutropenic diet and safe food handling be considered.

A transferrable IncL/M plasmid harboring a gene encoding IMP-1 metallo-ß-lactamase in clinical isolates of Enterobacteriaceae.

BACKGROUND: The worldwide spread of carbapenemase-producing Enterobacteriaceae (CPE) has reduced the clinical utility of carbapenems. Plasmids often play an important role in the spread of genes encoding drug-resistance factors, especially in the horizontal transfer of these genes among species of Enterobacteriaceae. This study describes a patient infected with three species of CPE carrying an identical transferrable IncL/M plasmid. METHODS: Clinical isolates of CPE were collected at St. Luke's International Hospital, Tokyo, Japan, from 2015 to 2019. Three species of CPE isolates, Enterobacter cloacae, Klebsiella aerogenes and Serratia marcescens, were isolated from a patient who developed severe gallstone pancreatitis associated with bloodstream infection, with all three isolates producing IMP-1 metallo-ß-lactamase. The complete sequences of the plasmids of the three isolates were determined by both MiSeq and MinION. The medical chart of this patient was retrospectively reviewed conducted to obtain relevant clinical information. RESULTS: The three CPE species carried an IncL/M plasmid, pSL264, which was 81,133 bp in size and harbored blaIMP-1. The genetic environment surrounding blaIMP-1 consisted of int1-blaIMP-1-aac(6')-IIc-qacL-qacEdelta1-sul1-istB-IS21. Conjugation experiments showed that S. marcescens could transmit the plasmid to E. cloacae and K. aerogenes. In contrast, pSL264 could not transfer from E. cloacae or K. aerogenes to S. marcescens. CONCLUSION: The IncL/M plasmid pSL264 harboring blaIMP-1 was able to transfer among different species of Enterobacteriaceae in a patient receiving long-term antimicrobial treatment. The worldwide emergence and spread of IncL/M plasmids harboring carbapenemase-encoding genes among species of Enterobacteriaceae is becoming a serious public health hazard.

Use of PCR in the diagnosis of pericardial amebiasis: a case report and systematic review of the literature.

BACKGROUND: Entamoeba histolytica (E. histolytica) is rarely identified as a cause of amebic pericarditis. We report a case of amebic pericarditis complicated by cardiac tamponade, in which the diagnosis was missed initially and was made retrospectively by polymerase chain reaction (PCR) testing of a stored sample of pericardial fluid. Furthermore, we performed a systematic review of the literature on amebic pericarditis. CASE PRESENTATION: A 71-year-old Japanese man who had a history of sexual intercourse with several commercial sex workers 4 months previously, presented to our hospital with left chest pain and cough. He was admitted on suspicion of pericarditis. On hospital day 7, he developed cardiac tamponade requiring urgent pericardiocentesis. The patient's symptoms temporarily improved, but 1 month later, he returned with fever and abdominal pain, and multiple liver lesions were found in the right lobe. Polymerase chain reaction of the aspiration fluid of the liver lesion and pericardial and pleural fluid stored from the previous hospitalization were all positive for E. histolytica. Together with the positive serum antibody for E. histolytica, a diagnosis of amebic pericarditis was made. Notably, the diagnosis was missed initially and was made retrospectively by performing PCR testing. The patient improved with metronidazole 750 mg thrice daily for 14 days, followed by paromomycin 500 mg thrice daily for 10 days. CONCLUSIONS: This case suggests that, although only 122 cases of amebic pericarditis have been reported, clinicians should be aware of E. histolytica as a potential causative pathogen. The polymerase chain reaction method was used to detect E. histolytica in the pericardial effusion and was found to be useful for the diagnosis of amebic pericarditis in addition to the positive results for the serum antibody testing for E. histolytica. Because of the high mortality associated with delayed treatment, prompt diagnosis should be made.

Vagococcus fluvialis as a causative pathogen of bloodstream and decubitus ulcer infection: Case report and systematic review of the literature.

BACKGROUND: Vagococcal infections are uncommon in humans; there are limited studies on the clinical manifestations, the optimal methods for identifications, and antimicrobial susceptibility testing for vagococcal infections. Here, we have reported a case of Vagococcus fluvialis-induced bacteremia and decubitus ulcer and have systematically reviewed other reported Vagococcus infections. CASE PRESENTATION: A 74-year-old man presented to our emergency department with muscle weakness on his left extremities, dysarthria, and altered mental status along with fever for the past 4 days. Physical examination revealed a decubitus ulcer with foul smelling and yellowish exudative pus on his left chest wall and abdomen, forearm, thigh, and lower leg. He was empirically treated with 2.25 mg of piperacillin/tazobactam every 8 hours and 0.5 g of vancomycin every 24 hours intravenously (IV) for his decubitus ulcer. Vagococcus fluvialis was detected in both aerobic and anaerobic blood cultures (upon admission) using the VITEC 2 GP ID card (bioMérieux) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). We continued the mentioned IV antimicrobial therapies for 4 weeks following which the patient was transferred to a long-term care facility for further rehabilitation. CONCLUSIONS: To our best knowledge, this is the first literature review of Vagococcus infections in humans. Since it is challenging to distinguish Vagococcus from Enterococcus by a conventional method due to the similarity of its biochemical properties to those of Enterococcus, based on our literature review, 16S rRNA sequencing or analysis of bacterial protein profile using MALDI-TOF MS may be useful for the precise identification.

Disseminated nocardiosis due to Nocardia terpenica.

We report the first case of disseminated nocardiosis due to trimethoprim/sulfamethoxazole-resistant Nocardia terpenica successfully treated with meropenem and clarithromycin. The patient travelled to Japan from Australia via Southeast Asia, which led to differential diagnoses of multiple lung nodules including miliary tuberculosis and melioidosis as well as nocardiosis. Because of variety of susceptibility depending on the Nocardia species, clinicians need to confirm the species and investigate its susceptibility.