Infection and Drug Resistance最新文献

Purpose: Staphylococcus warneri is an opportunistic pathogen responsible for hospital-acquired infections (HAIs). The aim of this study was to describe an outbreak caused by S. warneri infection in a neonatal intensive care unit (NICU) and provide investigation, prevention and control strategies for this outbreak.

Methods: We conducted an epidemiological investigation of the NICU S. warneri outbreak, involving seven neonates, staff, and environmental screening, to identify the source of infection. WGS analyses were performed on S. warneri isolates, including species identification, core genome single-nucleotide polymorphism (cgSNP) analysis, pan-genome analysis, and genetic characterization assessment of the prevalence of specific antibiotic resistance and virulence genes.

Results: Eight S. warneri strains were isolated from this outbreak, with seven from neonates and one from environment. Six clinical cases within three days in 2021 were linked to one strain isolated from environmental samples; isolates varied by 0-69 SNPs and were confirmed to be from an outbreak through WGS. Multiple infection prevention measures were implemented, including comprehensive environmental disinfection and stringent protocols, and all affected neonates were transferred to the isolation wards. Following these interventions, no further cases of S. warneri infections were observed. Furthermore, pan-genome analysis results suggested that in human S. warneri may exhibit host specificity.

Conclusion: The investigation has revealed that the outbreak was linked to the milk preparation workbench by the WGS. It is recommended that there be a stronger focus on environmental disinfection management in order to raise awareness, improve identification, and prevention of healthcare-associated infections that are associated with the hospital environment.

Background: The capsid inhibitor (CAI) lenacapavir (LEN) was approved for use in 2022, yet there are few reports about its drug resistance mutations (DRMs) and sensitivity.

Purpose: To delineate the prevalence of CAI DRMs and drug susceptibility among HIV-1 infected individuals living in Guangdong, China.

Patients and methods: A total of 1035 individuals with HIV-1 infection, including 660 highly Active Anti-Retroviral Therapy (HAART) naive individuals and 375 hAART experienced individuals whose protease (PR)/ reverse transcriptase (RT) fragments were amplified successfully during drug resistance surveillance between October 2021 and December 2023, were randomly included in this study. The entire HIV-1 gag gene was amplified from plasma in LEN-naive individuals with or without antiretroviral therapy. The epidemiological and demographic information of the enrolled individuals were collected. The Stanford HIV Drug Resistance Database HIVdb program for Capsid was used to interpret the CAI DRMs and the LEN susceptibility.

Results: Among 1035 samples, 805 gag sequences were amplified, sequenced and assembled successfully from 518 hAART drugs naive individuals and 287 hAART drugs experienced individuals. Among them, 0.50% (4/805) carried at least one CAI DRM, of which 0.19% (1/518) from HAART naive individuals and 1.05% (3/287) from HAART experienced individuals. Among the individuals with CAI DRMs, two patients carried CAI major mutations (Q67H) conferring intermediate resistance to LEN and two patients carried CAI accessory mutation (T107A) conferring low level resistance to LEN.

Conclusion: Extremely low prevalence of CAI DRMs was detected among people living with HIV (PLWH) in Guangdong, China. Our observations indicate that LEN application may be promising when used in clinical practice in China. Before the administration of LEN, there is no need to consider detecting CAI mutations in PLWH through DRM examination for the time being.

Purpose: Understanding the mode of Mycobacterium tuberculosis (M. tuberculosis) transmission is crucial for disease prevention and control. Compared to traditional genotyping methods, whole genome sequencing (WGS) provides higher resolution and comprehensive genetic information, enabling the tracing of infection sources and determining of transmission routes to resolve extensive tuberculosis (TB) outbreaks. We conducted a ten-year study on the transmission of M. tuberculosis in a population in eastern China.

Patients and methods: We selected Lianyungang, an eastern city in China, as the study site. Patients diagnosed with active pulmonary TB from 2011 to 2020 were enrolled as the study subjects. We isolated and sequenced 2252 M. tuberculosis. Strains with pairwise genetic distances of less than 12 single nucleotide polymorphisms were defined as genomic clusters and which were considered recent transmissions. Kernel density estimation and K-function analysis were applied to explore the spatial distribution of recently transmitted strains.

Results: After excluding non-tuberculous mycobacteria and duplicated samples, 2114 strains were included in the final analysis. These strains comprised lineage 2 (1593, 75.35%) and 4 (521, 24.65%). There were 672 clustered strains, with a recent transmission rate of 31.79%. The logistic regression model showed that the risk of recent transmission was high in students [adjusted odds ratio (aOR): 2.68, 95% confidence interval (CI): 1.63-4.49, P<0.001] and people infected with L2.2.1 strains (aOR: 1.59, 95% CI: 1.20-2.12). Higher spatial aggregation of TB transmission has been concentrated in Haizhou, Donghai, and Guanyun for the past 10 years. Three outbreaks affecting 46 patients were spatially spaced, with 11 to 23 persons each. Different groups exhibited varying geographic distances between the initial and later cases.

Conclusion: There are areas with a high risk of transmission for M. tuberculosis in the research site, and the risk varies among different populations. Accurate prevention strategies targeted at specific regions and key populations can help curb the prevalence of TB.

Streptococcus pyogenes, also known as Group A Streptococcus (GAS), can cause severe invasive diseases with high fatality rates. We report a case of necrotizing fasciitis and myositis complicated by Streptococcal Toxic Shock-Like Syndrome (STSS) caused by the invasive emm22/ST46 strain of Streptococcus pyogenes in China. A previously healthy 57-year-old Chinese Canadian man presented with right calf pain and ulceration following a hike in the Gobi Desert, which progressed to unconsciousness and severe infection. Despite initial treatment, his condition deteriorated, leading to his transfer to our intensive care unit. Metagenomic Next-Generation Sequencing identified Streptococcus pyogenes, and antimicrobial susceptibility testing revealed resistance to erythromycin, tetracycline, and clindamycin. Despite broad-spectrum antimicrobial therapy, debridement, and supportive measures, the patient's condition necessitated amputation of the right lower limb. He recovered and was discharged from the hospital on Day 43. Whole-genome sequencing of the isolate identified 15 multiple virulence factors. Phylogenetic analysis revealed that the closest relative of the isolate was a strain identified in China. This case underscores the importance of early recognition and treatment of invasive GAS infections to prevent severe outcomes, and we should pay attention to invasive emm22/ST46 GAS infections in China.

Purpose: The diagnosis of liver abscess (LA) caused by Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB) depends on ultrasonography, but it is difficult to distinguish the overlapping features. Valuable ultrasonic (US) features were extracted to distinguish GPB-LA and GNB-LA and establish the relevant prediction model.

Materials and methods: We retrospectively analyzed seven clinical features, three laboratory indicators and 11 US features of consecutive patients with LA from April 2013 to December 2023. Patients with LA were randomly divided into training group (n=262) and validation group (n=174) according to a ratio of 6:4. Univariate logistic regression and LASSO regression were used to establish prediction models. The performance of the model was evaluated using area under the curve(AUC), calibration curves, and decision curve analysis (DCA), and subsequently validated in the validation group.

Results: A total of 436 participants (median age: 55 years; range: 42-68 years; 144 women) were evaluated, including 369 participants with GNB-LA and 67 with GPB-LA, respectively. A total of 11 predictors by LASSO regression analysis, which included gender, age, the liver background, internal gas bubble, echogenic debris, wall thickening, whether the inner wall is worm-eaten, temperature, diabetes mellitus, hepatobiliary surgery and neutrophil(NEUT). The performance of the Nomogram prediction model distinguished between GNB-LA and GPB-LA was 0.80, 95% confidence interval [CI] (0.73-0.87). In the validation group, the AUC of GNB was 0.79, 95% CI (0.69-0.89).

Conclusion: A model for predicting the risk of GPB-LA was established to help diagnose pathogenic organism of LA earlier, which could help select sensitive antibiotics before the results of drug-sensitive culture available, thereby shorten the treatment time of patients.

Purpose: Hospital-acquired infections (HAIs) caused by multidrug-resistant organisms (MDROs) pose a significant challenge to healthcare systems. The present study aimed to evaluate the impact of the infection policy to COVID-19 on the incidence of HAIs caused by MDROs.

Methods: We conducted an eight-years retrospective analysis at a hospital in Shanghai, China. Bloodstream, sputum, and urinary tract cultures of MDROs obtained 48h after admission were collected monthly from January 2016 to Dec 2023. Occupied bed days (OBDs) were used to generate monthly HAI incidences per 10,000 OBDs. The study period was divided into pre-control, in-control, and post-control cohorts, in January 2020 and January 2022. The incidence was compared using interrupted time-series regression.

Results: In total, 6763 MDRO cultures were identified, comprising 1058 bloodstream, 4581 sputum, and 1124 urine cultures derived from 4549 patients. The incidence rates of all HAIs were 8.68 per 10,000 OBDs in the pre-control cohort, 9.76 per 10,000 OBDs in the in-control cohort and 12.58 per 10,000 OBDs in the post-control cohorts, respectively. A downward trend in the incidence of HAI was observed in the post-control cohort (p<0.05).

Conclusion: This study demonstrates that while the COVID-19 pandemic poses a significant challenge to infection control within hospitals, it provides a unique opportunity to enhance infection control measures and evaluate their effectiveness. In addition, these findings highlight the need for more targeted prevention and control strategies against different pathogens in future epidemics.

Purpose: Nucleotide-based matrix-assisted laser desorption ionization time-of-flight mass spectrometry (nucleotide MALDI-TOF MS) is an emerging molecular technology used for the diagnosis of tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB)and its drug resistance. This study aimed to compare the ability of nucleotide MALDI-TOF MS to detect rifampicin (RIF) resistance in drug-resistant TB (DR-TB) patients with Xpert MTB/RIF and to analyze the disparate results individually. Additionally, potential factors associated with rifampicin resistance among DR-TB patients in Qingdao were investigated.

Patients and methods: A retrospective study was conducted at Qingdao Chest Hospital, and patients with DR-TB were enrolled. Corresponding frozen isolates were recovered and subjected to nucleotide MALDI-TOF MS, Xpert MTB/RIF, and phenotypic drug susceptibility testing (pDST). Sanger sequencing was performed for the discordant results of nucleotide MALDI-TOF MS and Xpert MTB/RIF. Univariate and multivariate logistic regression analyses were used to identify potential factors associated with rifampicin resistance among patients with DR-TB.

Results: A total of 125 patients with DR-TB (18.8%, 125/668) were enrolled in this study from May 1 to July 31, 2023. Rifampicin-resistant (DR-TB/RR, 29) and rifampicin-sensitive (DR-TB/RS, 96) groups were divided according to the pDST results. Nucleotide MALDI-TOF MS performed better than Xpert MTB/RIF in terms of sensitivity, specificity, accuracy, and agreement with pDST. Only six cases had inconsistent results, and the sequencing results of five cases were identical to nucleotide MALDI-TOF MS. Furthermore, chest pain (aOR=12.84, 95% CI, 2.29-91.97, p=0.005), isoniazid sensitivity (aOR=0.14, 0.02-0.59, p=0.013), and ethambutol sensitivity (aOR=0.02, 0.00-0.10, p=0.000) were potential factors associated with rifampicin resistance among DR-TB patients in Qingdao.

Conclusion: The overall concordance between nucleotide MALDI-TOF MS and Xpert MTB/RIF was 95.2%, with the former performing better in determining rifampicin susceptibility among DR-TB cases in Qingdao. Chest pain, isoniazid, and ethambutol resistance might be factors associated with RIF resistance among patients with DR-TB in Qingdao.

Background: In the field of postoperative care, infections caused by Gram-positive bacteria pose a major clinical challenge. Vancomycin is a key therapeutic agent whose efficacy is greatly influenced by renal function, particularly by augmented renal clearance (ARC). The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimated glomerular filtration rate (eGFR) is an easy and commonly used method to predict ARC; however, it is not well studied to determine vancomycin dose. In this study, we examined the effectiveness of the CKD-EPI equation in determining ARC and optimizing the dose of vancomycin for surgical ward patients.

Methodology: A retrospective observational study was conducted to examine 158 surgical ward patients receiving vancomycin. Data on demographics, medical history, and vancomycin dosing were collected. Renal function was evaluated using the CKD-EPI equation, with ARC defined as eGFR ≥ 96.5 mL/min/1.73 m². Vancomycin pharmacokinetics were calculated using the ClinCalc tool.

Results: ARC was in 54% of the patients. Compared with patients without ARC, those with ARC were younger and had lower serum creatinine levels. They also required higher vancomycin doses but had lower trough concentrations and 24-hour area-under-the-curve values. A significant correlation was observed between eGFR and vancomycin clearance, with eGFR > 96.5 mL/min/1.73 m² necessitating higher vancomycin doses (>45 mg/kg/day) to achieve the desired area under the curve to minimum inhibitory concentration ratio.

Conclusion: For surgical ward patients with CKD-EPI eGFR ≥ 96.5 mL/min/1.73 m², a vancomycin dosage of >45 mg/kg/day may be recommended to reach effective therapeutic levels. Overall, this study emphasizes the importance of tailoring vancomycin therapy depending on renal function to ensure efficacy and mitigate the risk of antimicrobial resistance in surgical ward patients.

Bloodstream infections (BSIs) caused by Klebsiella pneumoniae (K. pneumoniae) are associated with high morbidity and mortality rates. This study presents a sequence type 25 (ST25) strain of hypermucoid K. pneumoniae A1 isolated from the blood of a patient with liver cirrhosis (LC) who succumbed to severe infections. We performed whole-genome sequencing of K. pneumoniae A1, which revealed virulence factors and antibiotic resistance genes. The strain harbors virulence genes encoding aerobactin, salmochelin, yersiniabactin, enterobactin, and rmpA. Additionally, the strain possessed five drug resistance genes: blaSHV-110, blaSHV-81, fosA6, OqxA, and OqxB. We further constructed a phylogenetic tree using 98 ST25 K. pneumoniae strains downloaded from NCBI together with K. pneumoniae A1. Phylogenetic analysis revealed that our isolated strain was closely related to a highly virulent strain isolated from a neonate in our region, differing by only 123 single nucleotide polymorphisms (SNPs). K. pneumoniae A1 is highly suspected to be Hypervirulent Klebsiella pneumoniae (hvKp). This study provided the first in-depth genomic analysis of ST25 K. pneumoniae in a patient with LC in China, highlighting the urgent need for early identification and diagnosis to combat this emerging threat.

Species of Pantoea are mainly environmental strains and plant pathogens, rarely causing human infections. Here, we describe two cases of hemodialysis catheter-related bloodstream infection caused by Pantoea in patients with uremia. To our knowledge, this is the first reported case of catheter related bloodstream infection caused by Pantoea dispersa (P. dispersa) in hemodialysis patients, as well as the first case of bloodstream infection caused by Pantoea anthophila (P. anthophila). Multiple blood cultures from the catheter showed the presence of Pantoea, and the isolated P. dispersa and P. anthophila were found to be highly sensitive to various antibiotics. Prompt use of antibiotics and catheter lock with gentamicin or amikacin led to rapid recovery of the patients, avoiding the economic burden of catheter replacement. Infections caused by Pantoea might be underestimated as methods such as VITEK^® MS system often result in misidentification. Therefore, we recommend using advanced techniques such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) or 16S ribosomal RNA analysis to detect more cases of Pantoea infections. By sharing these cases, we hope to increase awareness among clinicians about the potential pathogenicity of Pantoea in hemodialysis patients. It is crucial to strengthen noting the primary concern for sources of infection with Pantoea species (plant and environmental exposures) to prevent outbreaks of Pantoea-related bloodstream infections in hospitals.