Antibiotic Resistance Determinants and Virulence Factors of Hypervirulent and Carbapenem Non-Susceptible Pseudomonas aeruginosa.

BACKGROUND: The aim was to investigate the distribution of antibiotic resistance determinants and virulence factors in a group of carbapenem non-susceptible Pseudomonas aeruginosa (P. aeruginosa). METHODS: From March 2018 to May 2019, a total of 98 P. aeruginosa samples were collected from 6 hospitals in Ningbo and Hangzhou, Zhejiang Province, China. Drug susceptibility tests to 13 antimicrobial agents were conducted. The presence of antibiotic resistance determinants and virulence factors were investigated by PCR, including 39 ß-lactamase genes, 14 aminoglycoside modifying enzyme genes, 10 16SrRNA methylase genes, and 11 virulence genes. Phylogenetics of 98 P. aeruginosa was analyzed by sample cluster analysis (UPGMA). RESULTS: PCR revealed the presence of 7 ß-lactamase genes, 5 aminoglycoside modifying enzymes, 1 16S rRNA methylase gene, and 8 virulence genes in total, at least 2 ß-lactamase genes and 4 virulence genes were positive in every isolate. In addition, regional differences in distributions of resistance and virulence genes remained between 2 cities. Sample cluster analysis showed that the strains had obvious aggregation and were divided into several clusters, strains in the same cluster were isolated from different hospitals, even from different cities. CONCLUSIONS: Carrying resistance genes blaPDC and blaOXA-50 group and virulence genes plcH, aprA, and algD were the important epidemiological characteristics of this group of P. aeruginosa. The present findings provide insights into the mechanisms of hypervirulence as well as resistance to ß-lactams and aminoglycosides. To the best of our knowledge, this is the first report of blaPDC, blaOXA-50, and aph(3')-XV in P. aeruginosa in China.

Eikenella corrodens infections in human: Reports of six cases and review of literatures.

PURPOSE: To investigate clinical characteristics of six cases of Eikenella corrodens infection in Ningbo First Hospital in China in recent 2 years. METHODS: We retrospectively analyze medical records of six cases of E. corrodens infection in Ningbo First Hospital from 2020 to 2021. And we describe the gender, age, clinical manifestations, antimicrobial administration, and treatment of the six patients. RESULTS: Five of the patients had deep infection and they were treated with surgical drainage or abscess resection plus antimicrobial administration. After treatment, five patients were discharged and recovered well, and another patient was transferred to another hospital for further treatment. All the six cases were in line with the reports on the clinical characteristics of patients infected with E. corrodens at home and abroad before 2021. CONCLUSION: Eikenella corrodens is a part of the normal flora of human oropharynx, but it can migrate to other parts of the human body to cause severe invasive disease in humans. Although it is susceptible to most antimicrobials, it needs debridement in the treatment of deep infection.

Clinical features of patients with talaromycosis marneffei and microbiological characteristics of the causative strains.

BACKGROUND: Talaromyces marneffei (T. marneffei) is a temperature-dependent dimorphic fungus that is mainly prevalent in Southeast Asia and South China and often causes disseminated life-threatening infections. This study aimed to investigate the clinical features and improve the early diagnosis of talaromycosis marneffei in nonendemic areas. METHODS: We retrospectively analyzed the medical records of six cases of T. marneffei infection. We describe the clinical manifestations, laboratory tests, and imaging manifestations of the six patients. RESULTS: Talaromyces marneffei infection was confirmed by sputum culture, blood culture, tissue biopsy, and metagenomic next-generation sequencing (mNGS). In this study, there were five disseminated-type patients and two HIV patients. One patient died within 24 h, and the others demonstrated considerable improvement after definitive diagnosis. CONCLUSIONS: Due to the lack of significant clinical presentations of talaromycosis marneffei, many cases may be easily misdiagnosed in nonendemic areas. It is particularly important to analyze the imaging manifestations and laboratory findings of infected patients. With the rapid development of molecular biology, mNGS may be a rapid and effective diagnostic method.

Performance of the Colloidal Gold Immunochromatography of Cryptococcal Antigen on Bronchoalveolar Lavage Fluid for the Diagnosis of Pulmonary Cryptococcosis.

Objective: This study aimed to investigate the efficacy of the colloidal gold immunochromatography method in the detection of Cryptococcus antigen in bronchoalveolar lavage fluid (BALF) for pulmonary cryptococcosis (PC) diagnosis. Methods: A total of 111 patients with clinically suspected PC who were finally diagnosed with nonhuman immunodeficiency virus infection and hospitalized in the Ningbo First Hospital from March 2017 to December 2021 were retrospectively analyzed. All the confirmed cases were divided into two groups as follows: the PC group (33 cases) and the non-PC group (78 cases). All the patients were subjected to serum and BALF cryptococcal capsular polysaccharide antigen-lateral flow immunochromatographic assay (CrAg-LFA) and etiological culturing. Results: In the PC group, serum CrAg-LFA was positive for 24 and negative for 9 cases, serum Cryptococcus culture was positive for 1 and negative for 32 cases, BALF CrAg-LFA was positive for 31 and negative for 2 cases, and BALF Cryptococcus culture was positive for 9 and negative for 24 cases. In the non-PC group, serum CrAg-LFA was positive for 1 and negative for 77 cases, serum culture was negative in all the cases, and both BALF CrAg-LFA and culture were negative in all the cases. The sensitivity, specificity, and accuracy of BALF CrAg-LFA for PC diagnosis were 93.9%, 100%, and 98.2%, respectively, whereas those of BALF culture were 27.3%, 100%, and 78.4%, respectively. The sensitivity and accuracy of BALF CrAg-LFA were higher than that of serum CrAg-LFA and BALF etiological culture with statistically significant differences (p < 0.05). Conclusion: The diagnostic value of BALF CrAg-LFA for PC is superior to that of serum CrAg-LFA and BALF etiological culture.

Differential diagnosis of coronavirus disease 2019 pneumonia or influenza A pneumonia by clinical characteristics and laboratory findings.

BACKGROUND: Pneumonia caused by the 2019 novel Coronavirus (COVID-2019) shares overlapping signs and symptoms, laboratory findings, imaging features with influenza A pneumonia. We aimed to identify their clinical characteristics to help early diagnosis. METHODS: We retrospectively retrieved data for laboratory-confirmed patients admitted with COVID-19-induced or influenza A-induced pneumonia from electronic medical records in Ningbo First Hospital, China. We recorded patients' epidemiological and clinical features, as well as radiologic and laboratory findings. RESULTS: The median age of influenza A cohort was higher and it exhibited higher temperature and higher proportion of pleural effusion. COVID-19 cohort exhibited higher proportions of fatigue, diarrhea and ground-glass opacity and higher levels of lymphocyte percentage, absolute lymphocyte count, red-cell count, hemoglobin and albumin and presented lower levels of monocytes, c-reactive protein, aspartate aminotransferase, alkaline phosphatase, serum creatinine. Multivariate logistic regression analyses showed that fatigue, ground-glass opacity, and higher level of albumin were independent risk factors for COVID-19 pneumonia, while older age, higher temperature, and higher level of monocyte count were independent risk factors for influenza A pneumonia. CONCLUSIONS: In terms of COVID-19 pneumonia and influenza A pneumonia, fatigue, ground-glass opacity, and higher level of albumin tend to be helpful for diagnosis of COVID-19 pneumonia, while older age, higher temperature, and higher level of monocyte count tend to be helpful for the diagnosis of influenza A pneumonia.

The Characterization of OXA-232 Carbapenemase-Producing ST437 Klebsiella pneumoniae in China.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) was epidemic around the world and become a global threat to public health. The most important carbapenem-resistant mechanism is producing carbapenemases, especially Klebsiella pneumoniae carbapenemase (KPC), which is prevalent in the international clonal complex CC11. The high-risk multidrug-resistant CC11 is widespread worldwide, and KPC-producing and (New Delhi metallo) NDM-producing strains had been reported in this clonal complex before; moreover, cases with the CC11 strain faced more severe forms of drug resistance and treatment challenges than other clonal complexes. In this study, we identified an OXA-232-producing ST437 Klebsiella pneumoniae isolate in China, which belonged to CC11. The isolate was resistant to ß-lactams, aminoglycosides, and fluoroquinolones but susceptible to fosfomycin, tigecycline, and colistin. The bla OXA-232 gene was located on a 6141 bp ColKP3-type nonconjugative plasmid, and the plasmid was transformed by chemical transformation successfully. This is the first report of OXA-232-producing ST437 K. pneumoniae in China, a new clone of high-risk multidrug-resistant CC11.

False-negative cerebral spinal fluid cryptococcal antigen lateral flow assay due to postzone phenomenon in a patient with disseminated cryptococcal disease: a case report.

This report presents the case of false-negative cerebral spinal fluid (CSF) cryptococcal antigen (CrAg) lateral flow assay (LFA) in a HIV-positive 25-year-old male. The patient presented with headache, nausea and vomiting for 5 days and syncope for 1 day. An initial CSF CrAg LFA test was negative, but a 1:4 dilution of the CSF was weakly positive and a 1:8 dilution was positive. A serum cryptococcal antigen test was weakly positive. Cultures of blood and CSF were all positive for Cryptococcus neoformans. The explanation for the false-negative CSF CrAg LFA test is that the antigen concentration was too high causing the postzone phenomenon.

Clinical features and treatment outcomes of Vibrio vulnificus infection in the coastal city of Ningbo, China.

Background: Vibrio vulnificus is a gram-negative, opportunistic pathogen common to warm waters worldwide. Human V. vulnificus infection is rare and typically affects those residing in coastal areas during the summer months, but it causes rapid deterioration and is fatal. Methods: The medical records of six patients with sepsis caused by V. vulnificus infection who were treated at the First Affiliated Hospital of Ningbo University from 2020 to 2022 were retrospectively reviewed. The patient demographics, clinical symptoms, laboratory test results, treatments, and outcomes are summarized. Results: Vibrio vulnificus infection was confirmed by blood or pus culture, 16S ribosomal DNA sequencing, and metagenomic next-generation sequencing. All six patients were male with pre-existing liver diseases and two reported consuming seafood before the onset of symptoms. Of the six patients, four succumbed to the disease, two recovered, and one underwent leg amputation. Conclusion: Vibrio vulnificus infection progresses rapidly and is highly fatal, thus prompt and aggressive treatment is necessary. Vibrio vulnificus infection should be considered in older (>40 years) patients with a history of liver disease and recent consumption of seafood or exposure to seawater, especially those residing in coastal areas during the summer months.

Emergence of a clinical isolate of E. coil ST297 co-carrying blaNDM-13 and mcr-1.1 in China.

BACKGROUND: The coexistence of carbapenem resistance genes and mcr-1.1 in Enterobacterales has been an urgent and persistent threat to global public health. In this study, we isolated a clinical NB4833, an Escherichia coli isolate that co-carries mcr-1.1 and blaNDM-13. OBJECTIVES: This study aimed to isolate a clinical NB4833, an Escherichia coli isolate that co-carries mcr-1.1 and blaNDM-13 and investigated the phenotypic and genotypic characteristics of plasmids harbored by E. coli isolate NB4833. METHODS: Antimicrobial susceptibility testing and conjugation assay were performed on E. coli isolate NB4833. Stability of the plasmid and growth rate determination were used to characterize the plasmids harboring mcr-1.1 and blaNDM-13. In addition, the genetic characteristics of the plasmids were analyzed based on whole-genome sequencing of the strain and comparative genetic analysis with related plasmids. RESULTS: Whole-genome sequencing showed that the isolate carried multiple resistance genes and possessed phenotypes indicative of all antibiotic resistance except tigecycline. And the mcr-1.1- and blaNDM-13-harbouring plasmids showed relatively high similarity to the related plasmids. The pNB4833-NDM-13 plasmid was capable of trans conjugation with an efficiency of 1.04 × 10-2 in a filter mating experiment and the transconjugant J53/ pNB4833-NDM-13 was able to be stably inherited after 10 days of passage. CONCLUSIONS: To our knowledge, this is the first report of the coexistence of the IncI2 plasmid carrying mcr-1.1 and a blaNDM-13-carrying integrated IncFIB/IncFII plasmid in an ST297 clinical E. coli isolate. In addition, we investigated a novel plasmid carrying blaNDM-13. Our study expands the diversity of plasmids carrying blaNDM-13, which exhibits epidemic importance in bacterial resistance. Therefore, there are important measures that should be taken to prevent the spread of these plasmids.

Clostridium subterminale infection in a patient with diffuse large B-cell lymphoma and haemophagocytic syndrome: A case report and literature review.

Although uncommon, infection caused by Clostridium subterminale may be life threatening particularly in immunocompromised patients. We report here a rare presentation of a patient with diffuse large B-cell lymphoma and haemophagocytic syndrome associated with C. subterminale bacteraemia. The management of the patient is described as well as a review of medical literature. Infection by Clostridium species, including C. subterminale, should be considered in a febrile patient with a haematologic malignancy. The case highlights the importance of using gene sequencing for identification of this anaerobic organism.

Clinical and Microbiological Characteristics of a Community-Acquired Carbapenem-Resistant Escherichia coli ST410 Isolate Harbouring blaNDM-5-Encoding IncX3-Type Plasmid From Blood.

Objectives: The aim of this research was to investigate the clinical and microbiological characteristics of a case of community-acquired carbapenem-resistant Escherichia coli isolated from a patient with a bloodstream infection in China. Methods: Escherichia coli Huamei202001 was recovered from the first blood culture from a patient hospitalised in China. An antimicrobial susceptibility test was performed, and the genome was sequenced on an Illumina HiSeq X 10 platform with a 150-bp paired-end approach. The generated sequence reads were assembled using Unicycler, and the whole genome sequence data were analysed using bioinformatics tools. Moreover, the patient and her main family members obtained a faecal sample screening test for CRE, the positive strain was further isolated and the identification and antimicrobial susceptibility testing was performed. Results: Escherichia coli Huamei202001 belonged to sequence type 410. In addition, a blaNDM-5-encoding IncX3-type plasmid was responsible for the spreading of carbapenem resistance. Only the patient was detected as having a positive faecal sample screening test for CRE. Strain Fec01 was identified as E. coli, and the antibiotic susceptibility profile was the same as that of E. coli Huamei202001. Conclusions: Escherichia coli Huamei202001 is defined as community-acquired carbapenem-resistant Enterobacteriaceae. The clone ST410 that harbours the blaNDM-5-encoding IncX3-type plasmid is causing new high-risk clones globally. Thus, infection control measures should be strengthened to curb the dissemination of IncX3.

Investigation of antibiotic resistance determinants and virulence factors of uropathogenic Escherichia coli.

Multidrug-resistant (MDR) uropathogenic Escherichia coli (UPEC) are prevalent throughout the world resulting in a major public health burden. In this research, we isolated and identified 28 MDR UPEC from one university hospital in China, investigated MDR and pathogenic mechanisms by PCR, including 55 antibiotic resistance determinants (ARDs) genes, 13 genetic markers of mobile genetic elements (MGEs) and 6 virulence factors (VFs) genes. In these isolates, we identified 23 ARDs genes and 6 genetic markers of MGEs that played a key role in MDR phenotypes. In addition, we found 2 VFs genes, hofQ and ompT, which could be associated with pathogenicity and invasiveness of these strains in urinary tract infections (UTIs).

Dynamic change process of target genes by RT-PCR testing of SARS-Cov-2 during the course of a Coronavirus Disease 2019 patient.

We report the dynamic change process of target genes by RT-PCR testing of SARS-Cov-2 during the course of a COVID-19 patient: from successive negative results to successive single positive nucleocapsid gene, to two positive target genes (orf1ab and nucleocapsid) by RT-PCR testing of SARS-Cov-2, and describe the diagnosis, clinical course, and management of the case. In this case, negative results of RT-PCR testing was not excluded to diagnose a suspected COVID-19 patient, clinical signs and symptoms, other laboratory findings, and chest CT images should be taken into account for the absence of enough positive evidence. This case highlights the importance of successive sampling and testing SARS-Cov-2 by RT-PCR as well as the increased value of single positive target gene from pending to positive in two specimens to diagnose laboratory-confirmed COVID-19.

Draft Genome Sequence of a Klebsiella pneumoniae Strain (New Sequence Type 2357) Carrying Tn3926.

We present the draft genome sequence of a Klebsiella pneumoniae carbapenemase-producing sequence type 2357 (ST2357) strain, NB60, which contains drug-resistant genes encoding resistance to beta-lactams, fluoroquinolones, aminoglycosides, trimethoprim-sulfamethoxazole, colistin, macrolides, and tetracycline. Strain NB60 was isolated from human blood, making it an important tool for studying K. pneumoniae pathogenesis.

Draft Genome Sequence of Uropathogenic Escherichia coli Strain NB8.

Escherichia coli NB8 is a clinical pyelonephritis isolate. Here, we report the draft genome sequence of uropathogenic E. coli NB8, which contains drug resistance genes encoding resistance to beta-lactams, aminoglycosides, quinolones, macrolides, colistin, sulfonamide-trimethoprim, and tetracycline. NB8 infects the kidney and bladder, making it an important tool for studying E. coli pathogenesis.