A challenging case of carbapenem resistant Klebsiella pneumoniae-related pyogenic liver abscess with capsular polysaccharide hyperproduction: a case report.

BACKGROUND: Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections are a major public health problem, necessitating the administration of polymyxin E (colistin) as a last-line antibiotic. Meanwhile, the mortality rate associated with colistin-resistant K. pneumoniae infections is seriously increasing. On the other hand, importance of administration of carbapenems in promoting colistin resistance in K. pneumoniae is unknown. CASE PRESENTATION: We report a case of K. pneumoniae-related pyogenic liver abscess in which susceptible K. pneumoniae transformed into carbapenem- and colistin-resistant K. pneumoniae during treatment with imipenem. The case of pyogenic liver abscess was a 50-year-old man with diabetes and liver transplant who was admitted to Abu Ali Sina Hospital in Shiraz. The K. pneumoniae isolate responsible for community-acquired pyogenic liver abscess was isolated and identified. The K. pneumoniae isolate was sensitive to all tested antibiotics except ampicillin in the antimicrobial susceptibility test and was identified as a non-K1/K2 classical K. pneumoniae (cKp) strain. Multilocus sequence typing (MLST) identified the isolate as sequence type 54 (ST54). Based on the patient's request, he was discharged to continue treatment at another center. After two months, he was readmitted due to fever and progressive constitutional symptoms. During treatment with imipenem, the strain acquired blaOXA-48 and showed resistance to carbapenems and was identified as a multidrug resistant (MDR) strain. The minimum inhibitory concentration (MIC) test for colistin was performed by broth microdilution method and the strain was sensitive to colistin (MIC < 2 µg/mL). Meanwhile, on blood agar, the colonies had a sticky consistency and adhered to the culture medium (sticky mucoviscous colonies). Quantitative real-time PCR and biofilm formation assay revealed that the CRKP strain increased capsule wzi gene expression and produced slime in response to imipenem. Finally, K. pneumoniae-related pyogenic liver abscess with resistance to a wide range of antibiotics, including the last-line antibiotics colistin and tigecycline, led to sepsis and death. CONCLUSIONS: Based on this information, can we have a theoretical hypothesis that imipenem is a promoter of resistance to carbapenems and colistin in K. pneumoniae? This needs more attention.

Sclerosing angiomatoid nodular transformation of the spleen in a child with anemia: a case report and review of the literature.

BACKGROUND: Sclerosing angiomatoid nodular transformation of the spleen is a relatively rare benign vascular lesion in both adult and pediatric age groups with unclear etiopathogenesis and variable clinical presentations. Many benign and also malignant splenic masses could mimic sclerosing angiomatoid nodular transformation, both clinically and radiologically. Herein, we report our experience with a case of sclerosing angiomatoid nodular transformation in a 3-year-old girl. CASE REPORT: A 3-year-old Iranian girl presented with abdominal pain, back pain, and constipation for 2 weeks. She was being followed up by a pediatrician due to her short stature and persistent anemia. Physical examination showed stable vital signs, short stature, pallor, and a puffy face. Laboratory evaluation showed normochromic normocytic anemia with a normal reticulocyte count, ferritin, and hemoglobin electrophoresis. Radiologic assessments revealed a hypoechoic lesion in the spleen with high vascularity, clinically suspected to be lymphoma. She was operated on, and after partial splenectomy, pathologic evaluation of the spleen showed a solitary, well-demarcated, and unencapsulated dark mass. Microscopic examination revealed micronodular appearance composed of irregular-shaped vascular spaces lined by plump endothelial cells and surrounded by concentric collagen fibers, features in keeping with sclerosing angiomatoid nodular transformation. The patient's anemia was resolved after surgery, and no clinical or radiologic deficits were noted during the 10-month follow-up visits. CONCLUSION: Although sclerosing angiomatoid nodular transformation is exceedingly rare in children, it should be considered a differential diagnosis in pediatric splenic neoplasms with concurrent hematologic manifestations, such as anemia.

Emergence of K1 ST23 and K2 ST65 hypervirulent klebsiella pneumoniae as true pathogens with specific virulence genes in cryptogenic pyogenic liver abscesses Shiraz Iran.

Hypervirulent Klebsiella pneumoniae (hvKp) pathotype is emerging worldwide in pyogenic liver abscesses (PLAs). However, the role of virulence factors in pathogenicity remains unclear. On the other hand, the epidemiology of PLAs in Iran is unknown. From July 2020 to April 2022, bacterial species were isolated and identified from the drainage samples of 54 patients with PLAs. K. pneumoniae as the most common pathogen of pyogenic liver abscesses was identified in 20 (37%) of the 54 patients. We analyzed the clinical and microbiological characteristics of K. pneumoniae-related pyogenic liver abscesses. Antibiotic susceptibility testes and string test were performed. 16S rRNA, antibiotic resistance, and virulence genes were determined by polymerase chain reaction amplification. Clonal relatedness of isolates was identified by multilocus sequence typing. Virulence levels were assessed in the Galleria mellonella larval infection model. Four hvKp isolates (K1/K2) were found to be responsible for cryptogenic PLAs, and 16 classical K. pneumoniae isolates (non-K1/K2) were associated with non-cryptogenic PLAs. Three capsular serotype K1 strains belonged to sequence type 23 (ST23) and one K2 strain to ST65. Meanwhile, the non-K1/K2 strains belonged to other STs. ST231 was the most common strain among the classical K. pneumoniae strains. Compared with the non-K1/K2 strains, capsular serotypes K1/K2 strains were less resistant to antibiotics, had positive string test results, and had more virulence genes. In Galleria mellonella, a concentration of 106 colony-forming units of the K1 hvKp strain resulted in 100% death at 24 hours, confirming the higher virulence of the hvKp strain compared with cKp. K. pneumoniae isolates represented that the acquisition of any plasmid or chromosomal virulence genes contributes to pathogenicity and high prevalence in PLAs. Meanwhile, hvKp isolates with a specific genetic background were detected in cryptogenic PLAs.

Multifocal EBV-associated smooth muscle tumors in a patient with cytomegalovirus infection after liver transplantation: a case report from Shiraz, Iran.

INTRODUCTION: Immunodeficient patients, including the recipients of solid organs, exhibit an increase in the incidence of neoplasms. Post-transplant smooth muscle tumor (PTSMT) is a distinct and infrequent entity of these groups of neoplasms. Epstein-Barr virus (EBV) is considered to be involved in the etiology of this neoplasm. CASE REPORT: A 28-year-old man who underwent liver transplantation presented with abdominal pain and diarrhea for several months. He had a history of resistant systemic cytomegalovirus (CMV) infection after transplantation. Radiologic evaluation and colonoscopy revealed multiple liver, spleen, lung, and colon lesions. Microscopic assessment of colon and liver lesions using IHC study were in favor of spindle cell proliferation with mild atypia and a mild increase in mitotic rate without any necrosis, with features of smooth muscle tumor. Considering the transplantation history, EBER chromogenic in situ hybridization (CISH) study on paraffin blocks was requested, which demonstrated EBV RNA in tumor cell nuclei, suggesting EBV-associated smooth muscle tumor. In addition, PCR for CMV on paraffin blocks was positive. PCR for EBV and CMV viremia were negative. The dosage of immunosuppressive agents was reduced, and currently, he is being followed, with slow expansion in the size of the lesions. CONCLUSION: Although the incidence of post-transplant smooth muscle tumors (PTSMTs) is low, it should be remained in the differential diagnosis in post-transplantation patients, especially dealing with multifocal tumors. As strong stimulant for smooth muscle tumors, close follow-up and screening for EBV and CMV infection and early treatment at the time of diagnosis are recommended to avoid these virus-induced tumors.

The role of ultrasonography in detecting urinary tract calculi compared to CT scan.

OBJECTIVE: To evaluate the accuracy of ultrasonography (US) in measuring the urinary tract stone using non-contrast computed tomography (NCCT) as the standard reference. PATIENTS AND METHODS: A total of 184 patients suspected with urolithiasis who had undergone NCCT and US radiologic investigation from 2015 to 2017 were enrolled in this study. The sensitivity, specificity, and stone size measured in US were validated by NCCT. Data of the stone size in US were classified into four groups (0-3.5, 3.6-5, 5.1-10, >10 mm) and then compared with NCCT data. RESULTS: In 184 patients, NCCT detected 276 (97.2%) stones, while US could identify 213 (75.5%) stones. Overall sensitivity and specificity of US were 75.4% and 16.7%, respectively. Detection rate of mid and distal ureteral stone was lower than that at other locations. The detection rate increased with the stone size. About 73% concordance was obtained for the stone size measured by US and NCCT (Pearson's correlation coefficient was 0.841). Factors such as the stone size, amount of hydronephrosis, and weight affected the detection rate of the urinary tract stone using US (P<0.001, P=0.02, and P=0.01, respectively). CONCLUSION: The stone size obtained by US was almost the same as that detected by NCCT; however, US is a limited imaging modality in detecting urinary tract stone, especially when used by an inexperienced radiologist, and in the case of smaller stone size, increased weight, and low grade of hydronephrosis.