Original Article Efficacy and safety of colistin sulfate in the treatment of infections caused by carbapenem-resistant organisms: a multicenter retrospective cohort study Danyang Peng, Fan Zhang, Yinyin Chen, Congyi Zhao, Jingjing Niu, Jianxu Yang, Zhifeng Li, Chao Chen, Shi Qiu, Huifeng Zhang, Bingyu Qin, Xiang Fang, Suping Guo, Ying Liu, Huanzhang Shao

Objective: In intensive care units (ICUs), carbapenem-resistant Enterobacterales (CRE) pose a significant threat. We aimed to examine the distribution, epidemiological characteristics, and risk factors for CRE positivity in ICUs.Materials and methods: This cross-sectional study was conducted in 96 ICUs of 78 hospitals in Henan Province, China. The clinical and microbiological data were collected. A multivariable logistic regression model was used to analyze the risk factors for CRE positivity.Results: A total of 1,009 patients were enrolled. There was a significant difference in CRE positive rate between pharyngeal and anal swabs (15.16 vs. 19.13%, P < 0.001). A total of 297 carbapenem-resistant Klebsiella pneumoniae (CR-KPN), 22 carbapenem-resistant Escherichia coli (CR-ECO), 6 carbapenem-resistant Enterobacter cloacae (CR-ECL), 19 CR-KPN/CR-ECO, and 2 CR-KPN/CR-ECL were detected. Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-beta-lactamase (NDM), and a combination of KPC and NDM were detected in 150, 9, and 11 swab samples, respectively. Multivariable logistic regression analysis determined length of ICU stay, chronic neurological disease, transfer from other hospitals, previous infection, and history of antibiotics exposure as independent risk factors for CRE positivity. Age and cardiovascular diseases were independent risk factors for mixed infections of CRE. The occurrence of CRE in secondary and tertiary hospitals was 15.06 and 25.62%, respectively (P < 0.05). Patients from tertiary hospitals had different clinical features compared with those from secondary hospitals, including longer hospital stays, a higher rate of patients transferred from other hospitals, receiving renal replacement therapy, exposure to immunosuppressive drugs, use of antibiotics, and a higher rate of the previous infection.Conclusion: In ICUs in Henan Province, CRE positive rate was very high, mostly KPC-type CR-KPN. Patients with prolonged ICU stay, chronic neurological disease, transfer from other hospitals, previous infection, and history of antibiotic exposure are prone to CRE. Age and cardiovascular diseases are susceptibility factors for mixed infections of CRE. The CRE positive rate in tertiary hospitals was higher than that in secondary hospitals, which may be related to the source of patients, antibiotic exposure, disease severity, and previous infection.

Objective: This study aimed to explore the characteristics of carbapenem-resistant Enterobacterales (CRE) patients in the intensive care unit (ICU) in different regions of Henan Province to provide evidence for the targeted prevention and treatment of CRE. Methods: This was a cross-sectional study. CRE screening was conducted in the ICUs of 78 hospitals in Henan Province, China, on March 10, 2021. The patients were divided into provincial capital hospitals and nonprovincial capital hospitals for comparative analysis. Results: This study involved 1009 patients in total, of whom 241 were CRE-positive patients, 92 were in the provincial capital hospital and 149 were in the nonprovincial capital hospital. Provincial capital hospitals had a higher rate of CRE positivity, and there was a significant difference in the rate of CRE positivity between the two groups. The body temperature; immunosuppressed state; transfer from the ICU to other hospitals; and use of enemas, arterial catheters, carbapenems, or tigecycline at the provincial capital hospital were greater than those at the nonprovincial capital hospital (P < 0.05). However, there was no significant difference in the distribution of carbapenemase strains or enzymes between the two groups. Conclusions: The detection rate of CRE was significantly greater in provincial capital hospitals than in nonprovincial capital hospitals. The source of the patients, invasive procedures, and use of advanced antibiotics may account for the differences. Carbapenem-resistant Klebsiella pneumoniae (CR-KPN) was the most prevalent strain. Klebsiella pneumoniae carbapenemase (KPC) was the predominant carbapenemase enzyme. The distributions of carbapenemase strains and enzymes were similar in different regions.

Ureaplasma urealyticum, Ureaplasma parvum, and Mycoplasma hominis were widely known as ammonia-producing microorganisms and can cause hyperammonemia, leading to cerebral edema and altered consciousness, which represent serious complications in lung transplant recipients. However, there is limited knowledge on the epidemiology and outcomes of infections caused by U. urealyticum, U. parvum, and M. hominis in non-transplant patients with severe pneumonia in the ICU. Patients with severe pneumonia who underwent clinical metagenomics of bronchoalveolar lavage fluid (BALF) at the intensive care units (ICUs) of 17 medical centers from January 2019 to March 2023 were enrolled. All cases were divided into the positive group and the negative group based on whether U. urealyticum, U. parvum, or M. hominis was detected in lower respiratory tract. The clinical characteristics and outcomes were compared among the groups. The survival analysis after propensity score matching (PSM) was used to evaluate whether the mortality rate of U. urealyticum, U. parvum, and M. hominis positive patients were increased. Multivariate logistic regression was used to evaluate whether these microbials positivity were a risk factor for central nervous system dysfunction. In a total number of 1737 patients, 55 patients (3.17%) in the positive group and 1682 patients (96.83%) in the negative group. Patients in the positive group were younger, had a greater proportion of male patients, and had a longer time from ICU admission to clinical metagenomics testing. In contrast, the negative group had a higher proportion of patients with cerebrovascular disease. After PSM, there was no statistically significant difference in 28-day mortality following ICU admission between the two groups (hazard ratio [HR], 0.842; 95% confidence interval [CI], 0.489–1.451; p = 0.536). Multivariate logistic regression analysis showed an association between the detection of U. urealyticum, U. parvum, or M. hominis and neurological dysfunction (odds ratio [OR], 1.84; 95% CI 1.04–3.24; p = 0.035). The detection of U. urealyticum, U. parvum, or M. hominis in the lungs of patients is associated with neurological dysfunction.

Objective: Severe community-acquired pneumonia (sCAP) is one of the major diseases within the ICU. We hypothesize that subtyping sCAP based on simple inflammatory markers, organ dysfunction, and clinical metagenomics results is feasible.Method: In this study, we retrospectively enrolled immunocompetent sCAP patients requiring invasive mechanical ventilation, who underwent clinical metagenomics from 17 medical centers. We collected data on potentially pathogenic species reported by clinical metagenomics and clinical information for all patients. Latent class analysis (LCA) was applied to routine clinical parameters such as gender, age, white blood cell (WBC), lymphocytes, C-reactive protein (CRP), and Procalcitonin (PCT), identifying two optimally fitting models.Results: A total of 569 patients were enrolled. Compared to class B, class A was characterized by a younger age, higher CRP and PCT levels, and a higher incidence of coagulation dysfunction, liver failure, circulatory failure, and renal failure. However, the mortality rates were similar between the two groups. In class A, more cases of Streptococcus spp. and fewer cases of HSV-1 and Candida spp. were detected. Among the patients in the two phenotypes, 48.7% and 57.5% received corticosteroid treatment, respectively. In the class A, corticosteroid treatment was not associated with patient mortality (unadjusted hazard ratio (HR)=0.988; 95% confidence interval (CI), 0.634–1.541; p=0.959). In contrast, in the class B group, the use of corticosteroids was associated with a reduced mortality rate (adjusted HR=0.719; 95% CI, 0.525–0.986; p=0.04). Additional analysis showed that in class B, methylprednisolone was associated with reduced mortality (adjusted HR=0.61; 95% CI, 0.44–0.86; p=0.005), while dexamethasone was not associated with mortality (adjusted HR=1.4; 95% CI, 0.89–2.22; p=0.148). In addition, after dose conversion, the results showed that higher doses of corticosteroids in class B were associated with increased mortality (adjusted HR=1.01; 95% CI, 1.00–1.01; p=0.005).Conclusion: We identified two classes based on clinical metagenomics and clinical features. Class B exhibited a better response to corticosteroid compared to class A. The rapid identification of these phenotypes could facilitate the screening of sCAP patients responsive to corticosteroid in future prospective clinical trials.