Analysis of virulence profiles in clinical isolates of Klebsiella pneumoniae from renal abscesses: clinical significance of hypervirulent isolates.

Introduction: Klebsiella pneumoniae can cause a wide range of infections. Hypervirulent K. pneumoniae (hvKp), particularly associated with the K1 and K2 capsular types, is an increasingly significant microorganism with the potential to cause invasive infections, including renal abscesses. Despite the rising prevalence of hvKp infections, information on renal abscesses caused by K. pneumoniae is limited, and the clinical significance of hvKp associated with specific virulence genes remains elusive. Methods: This study performed at a 1200-bed tertiary hospital sought to identify the clinical and microbiological characteristics of renal abscesses caused by K. pneumoniae, focusing on various virulence genes, including capsular serotypes and multilocus sequence typing (MLST). Results: Over an 8-year period, 64 patients with suspected renal abscesses were reviewed. Ten patients diagnosed with K. pneumoniae-related renal abscesses were ultimately enrolled in the study. Among the isolates from the 10 patients, capsular serotype K2 was predominant (40.0%), followed by K1 (30.0%). The most common sequence type by MLST was 23 (40.0%). In particular, six patients (60.0%) harbored specific genes indicative of hvKp: iucA, peg-344, rmpA, and rmpA2. Conclusions: Our findings highlight the importance of hvKp as a pathogen in renal abscesses. Although the nature of hvKp is relatively unknown, it is widely recognized as a highly virulent pathogen that can infect relatively healthy individuals of various ages and simultaneously cause infections at multiple anatomical sites. Therefore, when treating patients with K. pneumoniae-related renal abscesses, caution is necessary when considering the characteristics of hvKp, such as potential bacteremia, multi-organ abscess formation, and metastatic spread.

Spontaneous splenic rupture associated with scrub typhus: a case report.

BACKGROUND: Scrub typhus, an acute febrile disease with mild to severe, life-threatening manifestations, potentially presents with a variety of complications, including pneumonia, acute respiratory distress syndrome, cardiac arrhythmias (such as atrial fibrillation), myocarditis, shock, peptic ulcer, gastrointestinal bleeding, meningitis, encephalitis, and renal failure. Of the various complications associated with scrub typhus, splenic rupture has rarely been reported, and its mechanisms are unknown. This study reports a case of scrub typhus-related spontaneous splenic rupture and identifies possible mechanisms through the gross and histopathologic findings. CASE PRESENTATION: A 78-year-old man presented to our emergency room with a 5-day history of fever and skin rash. On physical examination, eschar was observed on the left upper abdominal quadrant. The abdomen was not tender, and there was no history of trauma. The Orientia tsutsugamushi antibody titer using the indirect immunofluorescent antibody test was 1:640. On Day 6 of hospitalization, he complained of sudden-onset left upper abdominal quadrant pain and showed mental changes. His vital signs were a blood pressure of 70/40 mmHg, a heart rate pf 140 beats per min, and a respiratory rate of 20 breaths per min, with a temperature of 36.8 °C. There were no signs of gastrointestinal bleeding, such as hematemesis, melena, or hematochezia. Grey Turner's sign was suspected during an abdominal examination. Portable ultrasonography showed retroperitoneal bleeding, so an emergency exploratory laparotomy was performed, leading to a diagnosis of hemoperitoneum due to splenic rupture and a splenectomy. The patient had been taking oral doxycycline (100 mg twice daily) for 6 days; after surgery, this was discontinued, and intravenous azithromycin (500 mg daily) was administered. No arrhythmia associated with azithromycin was observed. However, renal failure with hemodialysis, persistent hyperbilirubinemia, and multiorgan failure occurred. The patient did not recover and died on the fifty-sixth day of hospitalization. CONCLUSIONS: Clinicians should consider the possibility of splenic rupture in patients with scrub typhus who display sudden-onset abdominal pain and unstable vital signs. In addition, splenic capsular rupture and extra-capsular hemorrhage are thought to be caused by splenomegaly and capsular distention resulting from red blood cell congestion in the red pulp destroying the splenic sinus.

Gastric ulcer and duodenitis associated with coinfection of human herpesvirus-8 and cytomegalovirus in a renal transplant recipient: a case report.

BACKGROUND: The coinfection between cytomegalovirus (CMV) and either human herpesvirus-6 (HHV-6) or HHV-7 in renal transplant recipients is well known; however, there have been few reports of coinfection of CMV associated with HHV-8. This paper presents a first case of acute gastric ulcer and duodenitis associated with CMV and HHV-8 coinfection after renal transplantation. CASE PRESENTATION: A 33-year-old male with a history of kidney transplantation was admitted to hospital because of postural epigastric pain. The recipient was CMV seropositive prior to transplantation and received trimethoprim-sulfamethoxazole without universal prophylaxis. Approximately 5 months after renal transplant, the recipient complained postural epigastric pain. An endoscopy revealed diffuse ulcerative lesions in the lower body and in the antrum of the stomach, as well as several erythematous mucosal lesions in the duodenum. Histopathologic examination identified CMV inclusions consistent with invasive CMV disease and immunohistochemical staining showed positive results for HHV-8 and CMV. No tumorous diseases such as Kaposi's sarcoma were detected. After 3 weeks of intravenous ganciclovir treatment, we observed that serum CMV PCR remained within the normal range and clinical symptoms improved. A follow-up endoscopy performed 3 weeks later showed that the severity of the above mentioned lesions had improved. CONCLUSIONS: We report the first case of a renal transplant recipient diagnosed with acute gastric ulcer and duodenitis associated with coinfection of CMV and HHV-8. Ganciclovir appears to be effective in diseases associated with coinfection of CMV and HHV-8.

Invasive Hypervirulent Klebsiella pneumoniae Syndrome Originating from an Anorectal Abscess as Opposed to a Pyogenic Liver Abscess.

An immunocompetent 49-year-old man presented with swelling and pain in the lower region of his left leg that had lasted for 4 weeks. The diagnosis was severe pyomyositis and osteomyelitis in the lower left leg caused by hypervirulent Klebsiella pneumoniae (hvKP) along with multiple metastatic infections in the kidneys, lungs, and brain originating from an anorectal abscess. A virulence-gene analysis revealed that the isolated K. pneumoniae harbored rmpA, entB, ybtS, kfu, iutA, mrkD, and allS-virulence genes and belonged to the K1 capsular serotype. After repeated abscess drainage procedures, intravenous ceftriaxone was administered for more than 10 weeks, and the patient's infection was controlled. We focused on the clinical features of hvKP originating from an anorectal abscess without a pyogenic liver abscess. We suggest that hvKP be considered a causative pathogen of pyomyositis and osteomyelitis resulting in multiple metastatic infections in an immunocompetent patient, and more information on the unexpected multiple metastatic infections should be obtained from a virulence analysis of K. pneumoniae.

Prostatic Abscess Caused by Klebsiella pneumoniae: A 6-Year Single-Center Study.

Hypervirulent Klebsiella pneumoniae (hvKp) is an important strain that can cause multiple organ infections. Although hvKp infection cases are increasing, there is limited information on the prostatic abscesses caused by K. pneumoniae. Furthermore, the clinical significance of hvKp associated with K1 or K2 capsular types or virulence genes in prostatic abscesses remains unclear. Therefore, we aimed to elucidate the clinical and microbiological characteristics of prostatic abscesses caused by K. pneumoniae in relation to various virulence genes. A retrospective study was performed at a 1200-bed tertiary hospital between January 2014 and December 2019. Patients diagnosed with prostatic abscesses with K. pneumoniae isolated from blood, urine, pus, or tissue cultures were enrolled in this study. Our results demonstrate that 30.3% (10/33) of the prostatic abscesses were caused by K. pneumoniae. All strains isolated from patients with prostatic abscesses due to K. pneumoniae were the K1 capsular type, and eight patients (80.0%) carried rmpA and iutA genes that identified hvKp. These findings suggest that hvKp is an important pathogen in prostatic abscesses. Therefore, when treating patients with K. pneumoniae prostatic abscesses, attention should be paid to the characteristics of hvKp, such as bacteremia, multiorgan abscess formation, and metastatic spread.

Clinical Features and Risk Factors Associated With 30-Day Mortality in Patients With Pneumonia Caused by Hypervirulent Klebsiella pneumoniae (hvKP).

BACKGROUND: Reports on metastatic or invasive infections by hypervirulent Klebsiella pneumoniae (hvKP) have increased recently. However, the effects of its virulence on clinical course and outcomes in pneumonia patients have rarely been addressed. We assessed and compared the clinical features of hvKp and classic K. pneumoniae (cKP) strains isolated from patients with pneumonia caused by K. pneumoniae. We also investigated the effects of virulence factors and the K. pneumoniae capsular serotypes K1 and K2 on mortality. METHODS: In this retrospective study, we enrolled 91 patients diagnosed as having pneumonia caused by K. pneumoniae and obtained their demographic and clinical data from medical records. We evaluated genes for K1 and K2, antimicrobial susceptibility, and the virulence genes rmpA, iutA, entB, ybtS, kfu, mrkD, and allS. Strains that possessed rmpA and iutA were defined as hvKP (N=39), while the remaining were classified as cKP (N=52). Odds ratio (OR) for the risk factors associated with 30-day mortality was calculated using the binary logistic regression model. RESULTS: The 30-day mortality in all patients was 23.1%; it was 17.9% (7/39) in the hvKP group and 26.9% (14/52) in the cKP group (P=0.315). Bacteremia (OR=38.1; 95% confidence interval [CI], 2.5-570.2), altered mental status (OR=8.8; 95% CI, 1.7-45.0), and respiratory rate >30 breaths/min (OR=4.8; 95% CI, 1.2-20.0) were independent risk factors for 30-day mortality in all patients. CONCLUSIONS: Our results suggest that hypervirulence determinants do not have a significant effect on 30-day mortality in patients with pneumonia caused by K. pneumoniae.

A Risk-Scoring System for Predicting Methicillin Resistance in Community-Onset Staphylococcus aureus Bacteremia in Korea.

AIMS: We aimed to develop a simple scoring system to predict risk for methicillin resistance in community-onset Staphylococcus aureus bacteremia (CO-SAB) by identifying the clinical and epidemiological risk factors for community-onset methicillin-resistant S. aureus (MRSA). METHODS: We retrospectively analyzed data from three multicenter cohort studies in Korea in which patient information was prospectively collected and risk factors for methicillin resistance in CO-SAB were identified. We then developed and validated a risk-scoring system. RESULTS: To analyze the 1,802 cases of CO-SAB, we included the four most powerful predictors of methicillin resistance that we identified in the scoring system: underlying hematologic disease (-1 point), endovascular infection as the primary site of infection (-1 point), history of hospitalization or surgery in ≤1 year (+0.5 points), and previous isolation of MRSA in ≤6 months (+1.5 points). With this scoring system, cases were classified into low (less than -0.5), intermediate (-0.5-1.5), and high (≥1.5) risk groups. The proportions of MRSA cases in each group were 24.7% (22/89), 39.0% (607/1,557), and 78.8% (123/156), respectively, and 16.7% (1/6), 33.8% (112/331), and 76.9% (10/13) in a validation set. CONCLUSIONS: This risk-scoring system for methicillin resistance in CO-SAB may help physicians select appropriate empirical antibiotics more quickly.

A Case of Jejunal Intussusception caused by Burkitt Lymphoma in an Acquired Immunodeficiency Syndrome Patient.

Non-Hodgkin's lymphoma of B-cell type is the second most common neoplasm after Kaposi's sarcoma among patients with human immunodeficiency virus infection. Most non-Hodgkin's lymphoma cases that are associated with acquired immunodeficiency syndrome (AIDS) involve extranodal sites, especially the digestive tract and the central nervous system. We report a case of multiple jejunal intussusception caused by Burkitt lymphoma in a 42-year-old AIDS patient. Upper gastrointestinal endoscopy and surgical biopsy were performed and a complete diagnostic study including histological and immunohistochemical analyses showed Burkitt lymphoma.

Successfully Managed Acute Transverse Myelitis Related to Scrub Typhus and Serial Image Findings.

Central nervous system involvement manifesting as meningitis or meningoencephalitis is a known complication of scrub typhus, but very few spinal cord lesions such as acute transverse myelitis (ATM) have been reported in association with this disease. Scrub typhus patients with a spinal lesion present with neurologic symptoms including dysuria, motor, and sensory weakness. Herein, we describe a rare case of ATM associated with scrub typhus. Clinical characteristics, cerebrospinal fluid cytology, Orientia tsutsugamushi serum antibody titer, and serial magnetic resonance imaging scans resulted in a diagnosis of ATM associated with scrub typhus.

Splenic infarction associated with acute infectious mononucleosis due to Epstein-Barr virus infection.

The purpose of this study was to report a case of a previously healthy 20-year-old woman diagnosed with splenic infarction following infectious mononucleosis (IM) by Epstein-Barr virus (EBV) infection and to perform the first systematic review of the clinical characteristics of splenic infarction associated with IM. A systematic review was conducted using English, French, and Japanese literatures of splenic infarction associated with IM due to EBV infection published between 1961 and 2015 in PubMed Medline. A total of 19 cases were extracted from the collected articles. Left upper quadrant (LUQ) pain was observed in 15 (79%) patients. Splenectomy was performed in five (26%) cases, among which four patients presented with stable vital signs. Splenic rupture was accompanied in two (10%) patients. The median time from the onset of IM symptoms to the diagnosis of splenic infarction was 5 days (range, 1-25 days). Fourteen (74%) of 19 patients experienced improvement through medical treatment, and there were no deaths. Splenic infarction associated with IM due to EBV infection can show a favorable clinical outcome after medical treatment. Clinicians should consider the possibility of splenic infarction when patients with IM experience LUQ pain. J. Med. Virol. 89:332-336, 2017. © 2016 Wiley Periodicals, Inc.

Risk factors for febrile neutropenia during chemotherapy for HIV-related lymphoma.

We evaluated risk factors for neutropenic fever and febrile prolonged neutropenia during vincristine-including chemotherapy to treat HIV-related lymphoma to investigate whether protease inhibitor (PI) treatment is associated with infectious complications due to drug interactions with chemotherapeutic agents. We included all HIV patients who received chemotherapy including vincristine for lymphoma at a single referral center in 1999-2010. Neutropenic fever was defined as absolute neutrophil count < 500 cells/µL with body temperature over 38℃; and prolonged neutropenia was defined if it persisted over 7 days. CODOX-M/IVAC and Stanford regimens were considered high-risk regimens for prolonged neutropenia. We analyzed 48 cycles of chemotherapy in 17 HIV patients with lymphoma. There were 22 neutropenic fever and 12 febrile prolonged neutropenia events. In multivariate analysis, neutropenic fever was associated with old age and low CD4 cell count, but not with PI use or ritonavir-boosted PI use. Low CD4 cell count and high-risk regimens were associated with febrile prolonged neutropenia. Neutropenic fever and febrile prolonged neutropenia is associated with old age, low CD4 cell count, and high-risk regimens, but not PI use, in HIV patients undergoing chemotherapy including vincristine for lymphoma.

Endoscopic submucosal dissection for rectal neuroendocrine (carcinoid) tumors.

PURPOSE: Rectal neuroendocrine (carcinoid) tumors smaller than 1 cm without lymph node metastasis and confined within the submucosal layer (stage T1aN0) can be treated using endoscopic resection. The present study was aimed to assess the safety and efficacy of endoscopic submucosal dissection (ESD) for T1aN0 carcinoid tumors. PATIENTS AND METHODS: A total of 35 consecutive patients with a T1aN0 rectal carcinoid tumor were enrolled between March 2007 and December 2009. The study evaluated the histologically complete resection rate, procedure time, complications, and short-term oncological outcomes. RESULTS: The mean patient age was 49.0 years (range, 32-74 years), and there were 25 men and 10 women. The mean procedure time was 35.6 minutes (range, 7-82 minutes). All neoplasms were removed in one piece, and the histologically complete resection rate was 74.3% (26 cases including 5 cases showing no residual tumor). No post-ESD bleeding was observed. Abdominal computed tomography scans showed a perforation in 1 patient only, but that perforation was not associated with any peritonitis symptoms, and the patient was discharged on postprocedure day 3. One patient underwent radical surgery after ESD because of angiolymphatic invasion and positive resection margins, and the final pathology revealed no residual tumor or lymph node metastasis. No patient showed local recurrence or distant metastasis during a median follow-up of 25 months (range, 12-43 months). CONCLUSIONS: ESD is feasible and safe for treating T1aN0 rectal carcinoid tumors. Further studies are required to accurately determine long-term oncological outcomes.