Infection and Drug Resistance最新文献

Background: Antimicrobial resistance (AMR) poses a significant global threat, particularly in low- and middle-income countries, such as Ethiopia, where surveillance is limited. This study aimed to predict and characterize the AMR profiles of diarrheagenic Escherichia coli (DEC) and nontyphoidal Salmonella (NTS) strains isolated from human, animal, food, and environmental samples using whole genome sequencing.

Methods: A total of 57 NTS and 50 DEC isolates were sequenced on an Illumina NextSeq 550. The ResFinder and PointFinder tools were employed to identify antimicrobial resistance genes (ARGs) and point mutations. Salmonella serotypes were determined using SeqSero.

Results: The analysis identified at least one ARG in every NTS sample and 78% of the DEC isolates, with 22 distinct ARGs in the NTS samples and 40 in the DEC samples. The most prevalent ARGs were aac(6')-Iaa and aph(3')-Ib, which predict aminoglycoside resistance in 100% of NTS and 54% of DEC isolates, respectively. Other commonly identified ARGs include sul2, aph(6)-Id, bla_TEM-1B , and tet(A), which confer resistance to folate inhibitors, aminoglycosides, β-lactams, and tetracycline. Some ARGs predicted phenotypic multidrug resistance in both DEC and NTS isolates. All identified β-lactam ARGs, except for bla_{TEM -1D}, conferred resistance to more than three antibiotics. Interestingly, bla_{CTX- M-15} was found to confer resistance to nine antibiotics, including third-generation cephalosporins, in 18% of DEC and 3.5% of NTS isolates. DEC isolates from children exhibited the highest ARG diversity. Notably, genes such as aph(3″)-Ib, aph(6)-Id, sul2, and tet(A) were detected across all sample types, including water sources, although some ARGs were exclusive to specific sample types. Point mutations mediating AMR were detected in several genes, with mutations associated with nucleotide substitution being the most frequent.

Conclusion: This genotypic AMR profiling revealed the presence of widespread drug-resistant NTS and DEC strains in Ethiopia. Robust and sustained AMR surveillance is essential for monitoring the emergence and spread of these resistant pathogens.

Moraxella catarrhalis (MC) is an aerobic Gram-negative cocci known to cause respiratory tract infections in humans as an opportunistic pathogen, with infections in other body parts being rare. This case involves an elderly female patient with a medical history of hypertension, type 2 diabetes, coronary heart disease, and osteoporosis. Following coronary angiography and lumbar spine surgery prompted by lower back and left lower limb pain, the patient developed persistent pus discharge from the lumbar spine wound post-surgery, which did not respond to conventional anti-infection therapy, leading to her transfer to our hospital. Upon examination, Direct Radiography (DR) diagram revealed gas accumulation and bone curling in the 4-5 intervertebral space, muscle layer, and fascia layer of the lumbar vertebrae. Subsequent culture of the wound pus confirmed the presence of MC, resulting in a diagnosis of postoperative lumbar spine infection. Treatment involved antibiotics administration, lesion clearance, spinal exploration, and autologous iliac bone transplantation for fusion, alongside the management of glucose levels and hypertension, anticoagulation therapy, as well as the use of Duhuo Jisheng Decoction to promote blood circulation and eliminate blood stasis. Following this comprehensive treatment approach, the patient achieved a full recovery and was discharged. To the best of our knowledge, this is the first reported case of Moraxella catarrhalis infection following lumbar spinal fixation and fusion in Sichuan Province, China. The exact cause of infection in this case remains unclear. However, this case emphasizes the importance of considering the colonization site and infection mechanism of MC beyond the respiratory tract, underscoring the need for vigilance in clinical practice beyond typical infection sites.

Purpose: Klebsiella michiganensis is an opportunistic pathogen that causes an increasing number of serious infections. This study aimed to investigate the etiology of the severe clinical symptoms of sepsis in preterm infants and the characterization of K. michiganensis isolates.

Patients and methods: Whole-genome sequencing (WGS) was performed on three strains isolated from an infected preterm infant. Additionally, the genomic sequences of 534 K. michiganensis strains were obtained from the NCBI database. To gain deeper insights into these strains, we utilized the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Clusters of Orthologous Groups (COG), and Pathogen Host Interactions (PHI) database annotation tools for comprehensive gene function analyses. Moreover, the multilocus sequence typing (MLST), EasyCGtree, and virulence factor database (VFDB) were employed to determine the sequence types (STs), construct phylogenetic trees, and identify potential virulence factors.

Results: Sequence analysis found that the three isolated strains had identical sequence characteristics and did not correspond to any of the known ST types. Virulence factor analysis revealed that the three strains harbored mrkABCDFHIJ, fimABCDEFGHIK, entABCDEFS, fepABCD, and capsule genes. These virulence factors are likely to play crucial roles in enhancing adhesion and metabolic capabilities, resisting phagocytosis (inducing immune cell damage), and ultimately contributing to prolonged bacteremia. The phylogenetic tree and comparative genomics of virulence factors showed the genetic and virulence factor diversity of the currently reported K. michiganensis strains.

Conclusion: We identified a novel strain of K. michiganensis that exhibits high virulence and leads to severe septicemia phenotypes in preterm infants. Furthermore, comparative genomic analysis of previously reported K. michiganensis strains revealed the existence of three clades. This comprehensive analysis provides novel insights into the genetic relationships and virulence factor profiles of diverse strains of K. michiganensis. In future, it will be necessary to investigate the concept of the high virulence of K. michiganensis to determine the treatment method.

Objective: This study investigated the distribution and resistance patterns of pathogens in the intensive care unit of a newly established hospital in Guizhou Province to promote the rational use of antibiotics to reduce multidrug resistance.

Methods: A retrospective analysis was conducted on the distribution of pathogens and changes in drug resistance in the ICU of a newly built hospital in Guizhou Province from March 2019 to December 2023. WHONET 5.6 was used to analyze the results.

Results: A total of 2444 culture samples were received, predominantly sputum (34.66%) and blood (23.36%) samples, with a steady annual increase in specimen types. A total of 572 pathogenic strains were isolated, predominantly from respiratory specimens (54.02%), including 345 Gram-negative bacteria (60.31%), 135 Gram-positive cocci (23.60%), and 92 fungi (16.08%). The most frequent pathogens included Acinetobacter baumannii (30.77%), Candida albicans (11.71%), and Klebsiella pneumoniae (9.97%). Drug sensitivity tests indicated a fluctuating resistance rate of Acinetobacter baumannii over the past five years. Staphylococcus aureus displayed strong in vitro activity against vancomycin, tigecycline, and linezolid, with no resistant strains identified. The detection rates of carbapenem-resistant Acinetobacter baumannii (CR-AB), carbapenem-resistant Pseudomonas aeruginosa (CR-PA), methicillin-resistant Staphylococcus aureus (MRSA), and strains producing extended-spectrum beta-lactamases (ESBL) were 86.78%, 26.79%, 32.45%, 70.27%, and 23.54%, respectively.

Conclusion: Compared with other countries in the world, China has increased its data on the prevalence of MDR pathogens and antibiotic resistance.The high resistance rate of Acinetobacter baumannii in the ICU underscores the need for effective infection control measures. Enhanced monitoring of CR-AB, ESBL-producing bacteria, and MRSA is essential, along with improved management of antibacterial drugs and the pursuit of new therapeutic options.

Purpose: Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as a significant public health threat, particularly as a superbug responsible for nosocomial infections. In this study, we report a novel sequence type 6758 of K. pneumoniae harboring the bla _NDM-1 gene.

Material and methods: Antimicrobial susceptibility testing was conducted according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). The complete genome sequence of the strain was determined using the Illumina NovaSeq 6000 platform and long-read MinION sequencer. Genomic features and resistance mechanisms of the strain were further comprehensively analysed using various bioinformatics approaches.

Results: Antimicrobial susceptibility testing revealed that this strain exhibited resistance to multiple antimicrobials, including ceftazidime, ceftriaxone, cefazolin, cefepime, imipenem, meropenem, ampicillin/sulbactam, and sulfamethoxazole/trimethoprim. The genome analysis identified sixteen resistance genes. The bla _NDM-1 carbapenemase gene is located on a 47,823 bp IncX3-type plasmid (pNDM-CRKP331). A total of 41 K. pneumoniae strains carrying similar IncX3-type plasmids were retrieved from the NCBI database, representing 20 sequence types (STs) across 11 countries. The most common resistance gene carried by these IncX3-type plasmids is bla _NDM, and all these plasmids contain only the bla _NDM gene. The bla _NDM-carrying IncX3-type plasmids are widely prevalent in K. pneumoniae in China, spanning 15 STs.

Conclusion: In summary, our study reports the first genome sequence of an ST 6758 K. pneumoniae strain containing the class B β-lactamase bla _NDM-1 isolated from a clinical sample. Given the global emergence of bla _NDM, measures should be taken to prevent the spread of these bla _NDM-carrying IncX3-type plasmids. Our findings contribute to the understanding of the transmission mechanisms of bla _NDM in K. pneumoniae.

Aim: This study aims to analyze the incidence of multidrug-resistant (MDR) retrospectively and extensively drug-resistant (XDR) infections, characteristics of patients with these infections, causative microorganisms, and mortality rates in a tertiary respiratory intensive care unit (ICU).

Material and method: Between 01.01.2022 and 31.12.2023, the data of patients treated in the third-level respiratory ICU were analyzed retrospectively. Adult patients over 18 years of age with MDR and XDR infections were included in the study. Demographic characteristics, age, gender, comorbid systemic diseases, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, Sequential Organ Failure Assessment (SOFA) score, mechanical ventilation support status, duration of ICU stay and prognosis of the patients were analyzed and recorded through the hospital information management system.

Results: The study included 261 patients. Of these patients, 184 (70.5%) were male, 77 (29.5%) were female, and their ages were 65.54 ± 14.43 years. The majority of the patients had chronic diseases such as chronic obstructive pulmonary disease, hypertension, coronary artery disease, malignancy, and diabetes mellitus. There was no statistically significant difference between the resistance status of Klebsiella spp. Pseudomonas spp. and Acinetobacter spp. and the prognosis of the patients (p>0.05). No statistically significant difference was found between MDR and XDR Klebsiella spp. Pseudomonas spp. and Acinetobacter spp. patients in terms of the need for invasive mechanical ventilation, non-invasive mechanical ventilation, respiratory support therapy with high flow, APACHE II score, SOFA score, length of stay in the ICU, and prognosis (p>0.05).

Conclusion: Early detection and close monitoring of MDR, XDR, and PDR bacterial strains are vital to combat antimicrobial resistance. This study shows that MDR and XDR infections are a major health problem in ICUs and that these infections have significant negative effects on patient prognosis.

Purpose: This study aimed to assess the immunological efficacy and the impact on weight of dolutegravir (DTG)-based antiretroviral therapy (ART) regimen in ART-naive people living with HIV (PLWH).

Methods: A prospective study was conducted on ART-naïve PLWH who treated with DTG-based or efavirenz (EFV)-based regimens in The Second Hospital of Nanjing. Based on previous studies, the sample size was 332 patients calculated by PASS software. Considering a 20% dropout rate, the expected sample size was 416 patients, which were 208 patients in the DTG and EFV groups, respectively.

Results: Among 416 enrolled participants, the median age was 30.0 years (25.0-43.0), 388 (93.3%) males. At baseline, patients in the DTG group had worse pre-treatment immune level, but with no significant difference in weight compared to the EFV group. After 12 months of follow-up, the CD4+ T-cell counts increased greater in the DTG group (P=0.036), while the CD4+/CD8+ T-cell ratio increased greater in the EFV group (P=0.014). There was no significant difference in the normalization of various immune indicators between the two groups. The weight gain of patients in the DTG group at different follow-up points was all significantly higher than that in the EFV group (P<0.05). Multivariate logistic regression analysis showed that DTG-based regimens (OR=4.524, 95% CI: 2.371-8.634, P<0.001), baseline VL ≥10^5 copies/mL (OR=2.563, 95% CI: 1.411-4.657, P=0.002), and baseline CD4+ T-cell counts <200 cells/μL (OR=2.595, 95% CI: 1.430-4.709, P=0.002) were risk factors for weight gain ≥5 kg during the 12-month follow-up period.

Conclusion: After 12 months of follow-up, the increase in CD4+ T-cell counts was higher in the DTG group than in the EFV group, but the overall immunological efficacy was similar in both groups. However, attention should be paid to patients' weight, especially in patients with high baseline viral load and low CD4+ T-cell counts who were treated with the DTG-based regimen.

Background: Severe Acute Respiratory Syndrome Virus 2 (SARS-CoV-2) primarily targets mitochondria. However, the description of mitochondrial signaling in immune cells remains limited in COVID-19. This study aimed to elucidate the pivotal roles played by immune cells and mitochondria in the pathogenesis of COVID-19 and the resulting clinical outcomes.

Methods: We obtained epidemiological characteristics, laboratory parameters and T cell mitochondrial damage indicators in 296 COVID-19 patients. And we further evaluated the predictive value of novel T lymphocyte mitochondrial markers and conventional immune inflammatory markers as clinical outcomes in COVID-19 patients. Finally, Binary logistic regression analysis was conducted to identify the independent risk factors associated with the prognosis of patients with COVID-19.

Results: The severe group exhibited lower counts of Mito+CD3+, Mito+CD4+, and Mito+CD8+ cells compared to the non-severe group. Significantly higher positive rates of CD3+, CD3+CD4+, and CD3+CD8+T cell mitochondrial damage were observed in the severe group compared to the non-severe group. The CD3+CD8+T cells MMP-low% had the highest AUC value of 0.864 (95% CI =0.794-0.934) to evaluate COVID-19 outcome. Binary logistic regression analysis showed that CD3+T cells MMP-low%, CD3+CD4+T cells MMP-low% and CD3+CD8+T cells MMP-low% were independent risk factors for adverse outcomes in COVID-19 patients.

Conclusion: Our research suggests that a substantial proportion of COVID-19 patients exhibited mitochondrial impairment with T-lymphocyte. T cells mitochondrial markers can serve as predictive factors and independent risk factors for predicting adverse outcomes in COVID-19 patients.

Purpose: Immunocompromised hosts are underrepresented in clinical trials. The goal of the study to search for the unmet needs in the management of CAP in immunocompromised hosts.

Patients and methods: An observational study was conducted with CAP patients documented immunocompromise or those aged over 65 who have at least one chronic visceral disease. We clinically assessed the eligible patients at the time of the presentation with a follow-up assessment on day three of admission. The data were statistically analyzed to assess the impact of variables on mortality.

Results: During a 15-month study period, 140 CAP patients were observed. The overall 30-day mortality rate was 17.8%. The mortality rate was significantly higher in patients with sputum cultures positive for Pseudomonas aeruginosa, or two bacteria (p=0.049). Tachypnea was a stronger predictor of mortality. Failure to achieve a treatment response within three days of treatment identified the population with the worst outcomes. Less than half of such patients survived past one month.

Conclusion: Dynamic response assessment emerged as potentially the strongest predictor of outcomes in CAP of susceptible hosts. We propose that immunocompromised CAP patients who fail to respond early to treatment face extremely high rates of mortality, identifying an unmet need.

Background: Staphylococcus aureus (S. aureus) was a prevalent pathogenic bacterium among children. Due to the extensive use of antibiotics, the sensitivity of S. aureus to these drugs has gradually declined. Since the 1960s, methicillin-resistant Staphylococcus aureus (MRSA) has emerged and spread worldwide, becoming a primary cause of both healthcare-associated (HA) and community-acquired (CA) infections. This retrospective study aimed to highlight the significance of S. aureus among bacteria isolated from children in Beijing, China, and to elucidate its antimicrobial resistance patterns.

Methods: Data on all S. aureus infections from 2013 to 2022 were collected from the microbiology department of Beijing Children's Hospital. Only the first isolate from the same kind of specimen was analyzed. Antimicrobial susceptibility tests were carried out by Vitek 2 automated system (bio Mérieux, France) or Kirby-Bauer disc diffusion method, according to the guidelines recommended by the Clinical and Laboratory Standards Institute (CLSI).

Results: During the decade-long research period, a total of 47,062 bacterial isolates were isolated from 433,081 submitted specimens, with 6477 of these isolates identified as S. aureus. The majority of patients with S. aureus infections belonged to the age group of infants under one-year-old, accounting for 37.9% of cases. S. aureus isolates were predominantly found in the Pneumology Department, and the most common source of these isolates was lower respiratory tract specimens, comprising 34.3% of the total. The resistance rates of S. aureus to penicillin and erythromycin were notably high, at 89.5% and 73.8%, respectively. In contrast, the resistance rates to linezolid, vancomycin, rifampicin, and moxifloxacin were remarkably low, at 0.0%, 0.0%, 1.3%, and 3.9%, respectively. The detection rate of MRSA was 27.8%. MRSA isolates were predominantly found in the newborn group, ICU, and sterile body fluids.

Conclusion: In our study, the most prevalent specimen type was derived from the lower respiratory tract, whereas the highest positive rate was observed in ear secretions. These findings underscored the pressing necessity for ongoing antimicrobial resistance (AMR) surveillance and the revision of treatment guidelines, particularly given the elevated detection of MRSA in ICU wards, sterile body fluids, and the neonatal age group. MRSA exhibited significant resistance to all β-lactam antibiotics, erythromycin, and ciprofloxacin. Therefore, future research endeavors should prioritize examining specific antimicrobial resistance populations and potential intervention strategies, as these were vital in mitigating the dissemination of antimicrobial-resistant isolates.