Meta-analysis of efficacy and safety of intravenous combined with intrathecal/intraventricular injection of polymyxin against intracranial infection with multidrug-resistant bacteria / 临床神经病学杂志

Objective Evaluation of the efficacy and safety of intravenous(IV)combined with intrathecal/intraventricular injection(ITH/IVT)of polymyxin against intracranial infection with multidrug-resistant bacteria.Methods The databases,including Wanfang,VIP,Chinese Biomedical Literature,Pubmed,Embase,ScienceDirect,and Cochrane Library were searched,case-control studies on IV+ITH/IVT polymyxin against intracranial infection with multidrug-resistant bacteria by January 2023 were screen.RevMan 5.4 software was used for meta-analysis.Results A total of 9 retrospective studies were included.The fatality rate in IV+ITH/IVT polymyxin group was significantly lower than that in IV group(OR =0.19,95%CI:0.11-0.35,P＜0.01).There was no significant difference in ICU hospitalization days(OR =-2.32,95%CI:-23.59-18.89,P =0.83)and adverse reaction rate(OR =0.93,95%CI:0.26-3.38,P =0.91)between IV+ITH/IVT group and IV group.Conclusion IV+ITH/IVT polymyxin in treating the intracranial infection with multidrug-resistant bacteria can significantly reduce fatality rate,and does not significantly increase adverse reactions.

Analysis of Treatment of Renal Atrophy Complicated with Multi-site Carbapenem-resist-ant Klebsiella Pneumoniae Infection / 医药导报

Objective To analyze the treatment of renal atrophy combined with multi-site carbapenem-resistant Kleb-siella pneumoniae(CRKP)infection,and to provide a reference for clinical rational drug use for such diseases.Methods Based on practical experience and referring to the latest literature,clinical pharmacists participated in the treatment of a case of renal atrophy complicated with multi-site CRKP infection.Recommendations were made,including adjusting the usage and dosage of meropenem,combining with polymyxin E,and timely de-escalation treatment.Results After the physician adopted the sug-gestion and adjusted the treatment plan,the patient's symptoms and infection indicators returned to normal,and the infection was effectively controlled.Conclusion Polymyxin E sodium methanesulfonate combined with high-dose meropenem had good clini-cal efficacy in the treatment of urinary tract and bloodstream infections caused by CRKP.

Clinical Observation of Shengmaisan Combined with Polymyxin B in Treatment of Sepsis Complicated with Severe Acute Respiratory Distress Syndrome / 中国实验方剂学杂志

ObjectiveTo observe the clinical efficacy of Shengmaisan combined with polymyxin B in the treatment of carbapenem-resistant gram-negative bacillus infection with sepsis complicated with severe acute respiratory distress syndrome. MethodA total of 90 patients suffering from carbapenem-resistant gram-negative bacillus infection with sepsis complicated with severe acute respiratory distress syndrome were randomly divided into a control group and an observation group， with 45 cases in each group. The control group was treated with polymyxin B， and the observation group was treated with Shengmaisan combined with polymyxin B. The treatment course of both groups was seven days. The infection-related indicators ［white blood cell （WBC） count， procalcitonin （PCT）， neutrophil apolipoprotein （HNL）］， inflammatory factors ［interleukin-6 （IL-6）， serum chemokine ligand 2 （CXCL2）］， and T lymphocyte subpopulations （CD3+， CD4+， CD8+， and CD4+/ CD8+ value）， acute physiological and chronic health Ⅱ （APACHE Ⅱ） score before and after treatment， as well as bacterial clearance rate and 28-day survival rate after treatment were observed. Result① The experiment was completed， and 81 cases were included， including 41 cases in the observation group and 40 cases in the control group. The general data of the two groups were comparable. ② The bacterial clearance rate of the observation group and the control group was 75.6% （31/41） and 52.5% （21/40）， respectively， and the observation group was higher than the control group （χ2=4.7， P<0.05）. ③ The WBC count， PCT， HNL， IL-6， CXCL2， and APACHE Ⅱ scores of the observation group and the control group all decreased after treatment （P<0.05）. Except for the WBC count， the PCT， HNL， IL-6， CXCL2， and APACHE Ⅱ scores of the observation group were lower than those of the control group （P<0.05）. ④ The values of CD3+， CD4+， and CD4+/CD8+ in the observation group were increased after treatment （P<0.05）， and CD8+ was decreased （P<0.05）. In the control group， only CD3+ value was increased （P<0.05）. The values of CD3+， CD4+， and CD4+/CD8+ in the observation group were higher than those in the control group， and the value of CD8+ was lower than that in the control group （P<0.05）. ⑤ The 28-day survival rate in the observation group was higher than that in the control group （χ2=4.3， P<0.05）. ConclusionShengmaisan combined with polymyxin B in the treatment of carbapenem-resistant gram-negative bacillus infection with sepsis complicated with severe acute respiratory distress syndrome can better clear bacteria， control infection， reduce the level of inflammatory factors， regulate the immune state of the body， and improve the short-term prognosis.

Efficacy and safety analysis of tigecycline and polymyxin B in the treatment of carbapenem-resistant enterobacteriaceae pneumonia in critically ill patients / 中国临床药理学与治疗学

AIM: To compare the efficacy and safety of tigecycline with polymyxin B in the treatment of carbapenem resistant enterobacteriaceae (CRE) pneumonia in critically ill patients. METHODS: A retrospective analysis was performed on the clinical data of patients with CRE pneumonia who received tigecycline or polymyxin B therapy from January 1, 2018 to Jun 30, 2023 in the Intensive Care Unit (ICU). Primary outcomes included the 28-day all-cause mortality and clinical cure rate within 28days. Secondary outcomes included the ICU mortality, in-hospital mortality, the length of hospital stay and ICU stay, microbial eradication, duration of mechanical ventilation. Independent predictors affecting 28-day clinical cure rate were tested using Cox regression analyses. RESULTS: A total of 83 eligible patients were included in the final analysis after propensity score matching, 54 in the tigecycline group and 29 in the polymyxin B group. The 28-day all-cause mortality was 31.5% (17/54) in the tigecycline group and 37.9% (11/29) in the polymyxin B group, the difference was not statistically significant (P=0.554); the clinical cure rate was 63% (34/ 54) in the tigecycline group, which was significantly higher than that of the polymyxin B group of 34.5% (10/29) (P = 0.013). There were no statistical differences between the two groups in terms of secondary outcomes. Multivariate logistic regression analysis found that the use of tigecycline was an independent predictor of the 28-day clinical cure rate (HR 2.083, 95%CI 1.018-4.263, P = 0.045). However, activated partial thromboplastin time (APTT) and prothrombin time (PT) were significantly prolonged in the tigecycline group compared with the polymyxin B group (P=0.047; P=0.027), and fibrinogen (FIB) was significantly decreased (P < 0.001) after drug administration. CONCLUSION: There was no significant difference in 28-day all-cause mortality between the tigecycline and polymyxin groups; tigecycline might be associated with a higher 28-day clinical cure rate compared with polymyxin B. It should be noted that tigecycline may increase the risk of coagulation abnormalities.

Impact of the national shortage of polymyxin B in critically ill patients during the COVID-19 pandemic / Impacto da escassez nacional de polimixina B em pacientes gravemente enfermos durante a pandemia de COVID-19 / Impacto del desabasto nacional de polimixina B en pacientes críticos durante la pandemia de COVID-19

Background and Objectives: during the COVID-19 pandemic, the number of critical patients requiring intensive care increased considerably, resulting in an increase in infections due to multi-resistant microorganisms. In Brazil, in 2021, due to the high demand for polymyxin B use, there was a national shortage of the medication. One strategy used to overcome this situation was aminoglycoside use. The work aimed to analyze the impact of replacing polymyxin B with amikacin and gentamicin in the final stage of patients. Method: an analytical study with an observational, cross-sectional design, with a quantitative approach, through a retrospective analysis through the analysis of medical records, with the primary stages being discharges or deaths. Results: mortality was similar between the group treated with aminoglycoside and the group treated with polymyxin B. Within the aminoglycoside group, mortality was higher in the group that had bacteria resistant to the drug than in the group that had infection with an organism sensitive to this drug. Mortality was not affected by comorbidities, age, or number of hospital infections. The main factor that led to the need for dialysis was the combination of two nephrotoxic medications. Conclusion: two hypotheses emerged: the first would be that replacing polymyxin B with aminoglycosides did not impact mortality; the other would be that, regardless of the antibiotic group used, patients had a high risk of death. Despite sample limitations, the study corroborates the adoption of strategies for the rational use of antimicrobials.(AU)

Justificativa e Objetivos: durante a pandemia de COVID-19, o número de pacientes críticos que necessitaram de cuidados intensivos aumentou consideravelmente, resultando em aumento de infecções por microrganismos multirresistentes. No Brasil, em 2021, devido à grande demanda pelo uso da polimixina B, houve escassez nacional do medicamento. Uma estratégia utilizada para superar essa situação foi o uso de aminoglicosídeos. O trabalho teve como objetivo analisar o impacto da substituição da polimixina B por amicacina e gentamicina na fase final dos pacientes. Método: estudo analítico com desenho observacional, transversal, com abordagem quantitativa, por meio de análise retrospectiva por meio de análise de prontuários, sendo as etapas primárias as altas ou óbitos. Resultados: a mortalidade foi semelhante entre o grupo tratado com aminoglicosídeo e o grupo tratado com polimixina B. Dentro do grupo aminoglicosídeo, a mortalidade foi maior no grupo que apresentava bactérias resistentes ao medicamento do que no grupo que apresentava infecção por organismo sensível a este medicamento. medicamento. A mortalidade não foi afetada por comorbidades, idade ou número de infecções hospitalares. O principal fator que levou à necessidade de diálise foi a combinação de dois medicamentos nefrotóxicos. Conclusão: surgiram duas hipóteses: a primeira seria que a substituição da polimixina B por aminoglicosídeos não impactou a mortalidade; a outra seria que, independentemente do grupo de antibióticos utilizado, os pacientes apresentavam alto risco de morte. Apesar das limitações amostrais, o estudo corrobora a adoção de estratégias para o uso racional de antimicrobianos.(AU)

Antecedentes y Objetivos: durante la pandemia de COVID-19, el número de pacientes críticos que requirieron cuidados intensivos aumentó considerablemente, resultando en un aumento de infecciones por microorganismos multirresistentes. En Brasil, en 2021, debido a la alta demanda del uso de polimixina B, hubo escasez nacional del medicamento. Una estrategia utilizada para superar esta situación fue el uso de aminoglucósidos. El trabajo tuvo como objetivo analizar el impacto de la sustitución de la polimixina B por amikacina y gentamicina en la etapa final de los pacientes. Método: estudio analítico con diseño observacional, transversal, con enfoque cuantitativo, mediante un análisis retrospectivo mediante el análisis de historias clínicas, siendo las etapas primarias las altas o defunciones. Resultados: la mortalidad fue similar entre el grupo tratado con aminoglucósido y el grupo tratado con polimixina B. Dentro del grupo de aminoglucósido, la mortalidad fue mayor en el grupo que tenía bacterias resistentes al fármaco que en el grupo que tenía infección con un organismo sensible a este. droga. La mortalidad no se vio afectada por las comorbilidades, la edad o el número de infecciones hospitalarias. El principal factor que llevó a la necesidad de diálisis fue la combinación de dos medicamentos nefrotóxicos. Conclusión: surgieron dos hipótesis: la primera sería que la sustitución de polimixina B por aminoglucósidos no impactó la mortalidad; la otra sería que, independientemente del grupo de antibióticos utilizado, los pacientes tenían un alto riesgo de muerte. A pesar de las limitaciones de la muestra, el estudio corrobora la adopción de estrategias para el uso racional de antimicrobianos.(AU)

Chinese consensus guidelines for therapeutic drug monitoring of polymyxin B, endorsed by the Infection and Chemotherapy Committee of the Shanghai Medical Association and the Therapeutic Drug Monitoring Committee of the Chinese Pharmacological Society / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Polymyxin B, which is a last-line antibiotic for extensively drug-resistant Gram-negative bacterial infections, became available in China in Dec. 2017. As dose adjustments are based solely on clinical experience of risk toxicity, treatment failure, and emergence of resistance, there is an urgent clinical need to perform therapeutic drug monitoring (TDM) to optimize the use of polymyxin B. It is thus necessary to standardize operating procedures to ensure the accuracy of TDM and provide evidence for their rational use. We report a consensus on TDM guidelines for polymyxin B, as endorsed by the Infection and Chemotherapy Committee of the Shanghai Medical Association and the Therapeutic Drug Monitoring Committee of the Chinese Pharmacological Society. The consensus panel was composed of clinicians, pharmacists, and microbiologists from different provinces in China and Australia who made recommendations regarding target concentrations, sample collection, reporting, and explanation of TDM results. The guidelines provide the first-ever consensus on conducting TDM of polymyxin B, and are intended to guide optimal clinical use.

Risk factors analysis of drug-induced kidney injury by intravenous polymyxin B / 中华急诊医学杂志

Objective:This study aims to explore the impact of various clinical factors on the risk of polymyxin B induced DKI in patients.Methods:This is a single-center retrospective case-control study. A total of 139 patients receiving polymyxin B intravenous treatment in our hospital from January 1 to December 31, 2020 were collected. Baseline variables between polymyxin B induced DKI group and non-DKI group were compared using the Chi-square test or Fisher's exact test for categorical variables and the T-test or Wilcoxon rank sum test for continuous variables, as appropriate. Statistical analysis was performed using univariate and multivariate Logistic regression models, Logistic regression models, multivariate Logistic regression models, Kaplan Meier curve, as well as Log-Rank test.Results:Among a total of 139 patients receiving polymyxin B treatment, 49 cases have experienced DKI, 90 cases did not. The incidence of DKI was 35.25%. There was no statistical difference in general information of age, gender, and proportion of standard weight between the two groups. Among the related indexes of polycolistin B administration, the proportion of high daily dose [>25 000 U/(kg·d)] and the total dosage of medication in the DKI group were both significantly higher than that in the non-DKI group ( P< 0.05, respectively). Among the organ function indexes, there were significant differences in initial serum creatinine, blood urea nitrogen, uric acid, urinary occult blood and urinary specific gravity between DKI group and non-DKI group 48 hours before polymyxin B administration ( P< 0.05). Binary Logistic regression analysis suggested that daily dose and initial creatinine before medication were independent risk factors for DKI caused by polymyxin B ( P< 0.05). Kaplan-meier survival analysis showed that with the accumulation of Polymyxin B administration, the higher the daily dose of Polymyxin B was, the faster the DKI occurred (Log-Rank P= 0.0194). Conclusions:Using intravenous polymyxin B is associated with the risk of DKI, among which higher initial blood creatinine values and higher daily doses are independent risk factors for DKI.

Quantitative analysis of polymyxin B in human serum by LC-MS/MS / 药物流行病学杂志

Objective To develop a simple and sensitive LC-MS/MS method for the determination of polymyxin B in human serum.Methods Polymyxin E2 was used as an internal standard and acetonitrile(0.1%formic acid)was used for protein precipitation.Chromatographic separation was performed on a Hypersil GOLDTM C18 column.Mobile phase A was 0.1%formic acid in water,and mobile phase B was methanol.The flow rate was 0.4 mL·min-1,with gradient elution.The column temperature was 40℃.The injection volume was 2 μL and the analysis time was 3.3 min.Multiple reaction monitoring and electrospray ion source positive ion mode were applied for quantitative analysis.The quantitative analysis ion pairs were m/z 402.10>101.10(polymyxin B1),m/z 397.45>101.10(polymyxin B2),m/z 578.50>101.10(polymyxin E2).Results The linear relationship of polymyxin B1 was at 22-15 000 ng·mL-1 and B2 was at 5-1 700 ng·mL-1 in human serum,which achieved excellent linearity,and the correlation coefficient was higher than 0.999 0.The lower limit of quantification of polymyxin B1 and B2 were 22 ng·mL-1 and 5 ng·mL-1,respectively.The accuracies were 95.98%-104.60%for polymyxin B1,98.11%-105.59%for polymyxin B2,respectively.The RSDs of intra-and inter-day precision were less than 15%.The recoveries of polymyxin B1 and B2 were 97.26%-103.31%and 95.81%-101.22%,respectively,and the matrix effects were 96.52%-109.54%and 93.29%-109.95%,respectively.The RSDs of the samples were all less than 15%.The mean AUC0-24h was(72.85±17.87)mg·h·L-1 in six patients.Conclusion The established LC-MS/MS method for determining polymyxin B in human serum meets the requirements of biological sample analysis.It is suitable for determining polymyxin B in human serum.

Risk factors of infection with polymyxin resistant and carbapenemase-resistant Klebsiella pneumoniae / 中华临床感染病杂志

Objective:To investigate the risk factors of infection with polymyxin resistant and carbapenemase-resistant Klebsiella pneumoniae（PR-CRKP）. Methods:A total of 170 patients with CRKP infection admitted in the Third Affiliated Hospital of Soochow University from July 2020 to October 2023 were enrolled，including 123 cases of CRKP infection and 47 cases of PR-CRKP infection. The general conditions，exposure of antibacterial drugs 6 months before admission，laboratory test indicators at admission，antibacterial drug use when target bacteria were detected，length of hospital stay and time of invasive procedures in two groups were retrospectively analyzed. The risk factors of PR-CRKP infection were analyzed with univariate and multivariate logistic regression. SPSS 26.0 software was used to analyze the data.Results:Univariate analysis showed that compared with the CRKP group，the average age of patients in PR-CRKP group was older（ Z = -2.186， P = 0.029），the proportion of patients with exposure history to semisynthetic penicillins，carbapenems，polymyxins，and quinolones 6 months before admission was higher（ χ 2= 3.930，5.414，11.939，8.478，all P < 0.05），the proportion of infections diagnosed at admission and blood urea nitrogen levels（ χ 2= 7.268， Z = -2.406， P = 0.007 and 0.016）was higher，the hemoglobin level（ t = 2.641， P = 0.009）was lower，the length of hospital stay was longer，the rates of tracheal intubation，urinary catheter，and deep vein catheterization were higher（ Z = -4.243，-4.660，-5.341，-4.583，all P < 0.001），the duration of carbapenem and polymyxin B use was longer（ Z = -4.757，-7.554，both P < 0.001），the proportion of combined quinolone-resistant Escherichia coli（QREC）and carbapenem-resistant organism（CRO）infections and bloodstream infections，and the rate of admission to intensive care units was higher（ χ 2 = 33.737，42.041，5.426，12.991， P < 0.05 or < 0.01）. Multivariate analysis showed that time to polymyxin B use（ OR = 1.179， 95%CI 1.059-1.312， P = 0.003），combined QREC infection（ OR = 5.357， 95%CI 2.100-13.669， P < 0.001）and combined CRO infection（ OR = 3.302， 95%CI 1.146-9.514， P= 0.027）were independent risk factors for PR-CRKP. Conclusion:Prolonged use of polymyxin B is an independent risk factor for PR-CRKP，and mixed QREC and CRO infection can increase the risk of PR-CRKP.

Efficacy and safefy of Polymyxin B treatment for neutropenic patients suffering from refractory Gram-negative bacterial bloodstream infection / 中华血液学杂志

Objective: To assess the efficacy and safety of polymyxin B in neutropenic patients with hematologic disorders who had refractory gram-negative bacterial bloodstream infection. Methods: From August 2021 to July 2022, we retrospectively analyzed neutropenic patients with refractory gram-negative bacterial bloodstream infection who were treated with polymyxin B in the Department of Hematology of the First Affiliated Hospital of the Soochow University between August 2021 to July 2022. The cumulative response rate was then computed. Results: The study included 27 neutropenic patients with refractory gram-negative bacterial bloodstream infections. Polymyxin B therapy was effective in 22 of 27 patients. The median time between the onset of fever and the delivery of polymyxin B was 3 days [interquartile range (IQR) : 2-5]. The median duration of polymyxin B treatment was 7 days (IQR: 5-11). Polymyxin B therapy had a median antipyretic time of 37 h (IQR: 32-70). The incidence of acute renal dysfunction was 14.8% (four out of 27 cases), all classified as "injury" according to RIFLE criteria. The incidence of hyperpigmentation was 59.3%. Conclusion: Polymyxin B is a viable treatment option for granulocytopenia patients with refractory gram-negative bacterial bloodstream infections.

Mechanism of polymyxin resistance related to lipopolysaccharide modification in carbapenem-resistant Klebsiella pneumoniae / 中华微生物学和免疫学杂志

Objective:To investigate the mechanism of polymyxin resistance related to lipopolysaccharide modification in carbapenem-resistant Klebsiella pneumoniae (CRKP). Methods:Plasmid-mediated drug resistance genes in seven CRKP strains were detected by conjugation assay and mcr gene detection. The expression of polymyxin resistance-related genes was measured using quantitative real-time PCR. The complete genomes of CRKP strains were sequenced. Silver staining and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) were performed to analyze the changes in lipopolysaccharide (LPS). Results:The seven CRKP strains were negative for mcr genes and the results of conjugation assay were also negative. Moreover, no mobile genetic elements related to drug resistance were detected. Compared with wild-type strain, all seven CRKP strains that were resistant to polymyxin showed increased expression of pmrA, pmrB and pmrC genes at the transcriptional level; six showed increased expression of phoP/ phoQ genes; three showed decreased expression of crrA/ crrB genes; four showed decreased expression of mgrB gene. The missense mutation sites in drug-resistant strains were mainly in KPHS_09430, KPHS_35900, KPHS_39520 and KPHS_52420. IS Kpn14 insertion sequence was detected in CRKP-6 strain. MALDI-TOF-MS reveals the modification of natural lipid A with L-Ara4N in CRKP LPS. Conclusions:LPS modification induced by chromosome-mediated mutation in the two-component regulatory system was the main molecular mechanism of polymyxin resistance in CRKP isolates in this study. Effects of the mutation in the two-component system on polymyxin resistance varied in different strains.

Clinical observation of polymyxin B in the treatment of CRKP-BSI in patients with hematological malignancies / 中国药房

OBJECTIVE To analyze the efficacy and safety of polymyxin B in the treatment of carbapenem-resistant Klebsiella pneumoniae （CRKP）-bloodstream infection （BSI） in patients with hematologic malignancies. METHODS The medical records of patients with hematologic malignancies with CRKP-BSI who received polymyxin B for at least 3 days in our hospital from September 2019 to June 2021 were retrospectively analyzed. All patients were initially treated with a triple therapy namely polymyxin B+tigecycline+carbapenems for anti-infection therapy. RESULTS A total of 10 patients were enrolled as the study subjects. Eleven strains of CRKP were cultured in blood， including 10 strains of CRKP produced Klebsiella pneumoniae carbapenemase（KPC） and 1 strain of CRKP produced both KPC and metal-beta-lactamase； 9 strains were sensitive to colistin， 7 strains were sensitive to tigecycline， 5 strains were sensitive to amikacin and 2 strains were sensitive to compound sulfamethoxazole. All patients were accompanied by neutropenia， with an average duration of （14.1±6.4） days. They were all characterized by fever， chills and fatigue. After treatment， 6 patients were cured and discharged， 4 patients died of ineffective treatment of septic shock. No serious adverse events related to polymyxin B occurred in all patients. CONCLUSIONS Polymyxin B can be used as a therapeutic drug for CRKP-BSI in patients with hematological malignancies. No serious adverse event related to polymyxin B occurs during the treatment.

Determination of polymyxin B concentration in plasma and its application in critically ill patients / 中国药房

OBJECTIVE To establish a method for the determination of polymyxin B concentration in plasma and apply it to clinical practice. METHODS After precipitated with 5% trichloroacetic acid solution， using polymyxin E2 as internal standard， the concentrations of polymyxin B1 and B2 in plasma sample were determined by UPLC-MS/MS. The determination was performed on BEH C18 chromatographic column with water （0.1% formic acid）-acetonitrile （0.1% formic acid） as mobile phase （gradient elution） at the flow rate of 0.5 mL/min. The sample size was 10 µL. The detection was accomplished with electrospray ionization operated in positive ion scanning by multi-reaction monitoring mode. The ion pairs for quantitative analysis were m/z 603.2→101.2 （polymyxin B1）， m/z 595.7→101.1 （polymyxin B2） and m/z 578.5→101.1 （internal standard）. The plasma concentration of polymyxin B in 79 critically ill patients was measured by the above method， the occurrence of acute renal injury （AKI） was recorded and the relationship of polymyxin B concentration in plasma with AKI was analyzed. RESULTS The linear ranges of polymyxin B1 and polymyxin B2 were 200-20 000， 50-5 000 ng/mL （r＞0.995）， and the lower limits of quantification were 200 and 50 ng/mL， respectively. RSDs of intra‐day and inter‐day precision tests were not higher than 12.06%， the average extraction recovery was 103.04%-117.44%， and RSDs of matrix effect test and stability test were all not higher than 7.42%. Steady state trough and peak plasma concentration were （2.54±2.52） and （8.17±5.20） mg/L for 79 clinical patients using polymyxin B. Eighteen patients out of 27 included patients developed AKI， with an incidence of 66.67%. The peak concentration of polymyxin B of patients without AKI was significantly lower than that of patients with AKI （P＜0.05）， but there was no significant difference in the trough concentration between two groups （P＞0.05）. CONCLUSIONS The established UPLC-MS/MS has the advantages of simple operation and high sensitivity， and can be used to monitor the plasma concentration of polymyxin B in patients. The occurrence of AKI is correlated with the peak concentration of polymyxin B.

Analysis and evaluation of the application of polymyxin B in inpatients based on clinical guidelines and consensuses / 中国药房

OBJECTIVE To evaluate the rationality of clinical application of polymyxin B in the inpatients of a third grade class A hospital，so as to provide evidence for the optimization of clinical scheme of the drug. METHODS A retrospective method was conducted on the electronic medical records of inpatients treated with Polymyxin B sulfate for injection from January 2020 to March 2022 to collect the basic information of patients， inpatient departments and time， infection diagnosis， results of pathogenic bacteria test， laboratory test indicators， usage and dosage， and combined medication，etc. Based on the drug instructions， according to relevant guidelines and consensus， the rationality， efficacy and safety of polymyxin B in inpatient were evaluated. RESULTS & CONCLUSIONS A total of 101 inpatients were included， respiratory system infection was the main cause （62.4%）. All patients had received the etiological examination， and the pathogen with the highest detection rate was carbapenem‑resistant Acinetobacter baumannii （40.6%）. One hundred patients were treated by intravenous drip， and 4 patients were treated by combination of aerosol inhalation or intrathecal injection； 99 patients were given the dose of 500 thousand units by continuous intravenous infusion， q12 h. Totally 51.5% of patients were treated for 7-14 days； and 77 patients were treated with other anti-Gram-negative drugs. There were unreasonable phenomena including too short time of medication （29.7%）， no combination of medication （23.8%）， and no indication of medication （17.8%）. The clinical effective rate of 101 patients treated with polymyxin B was 49.5%， and 16 patients （15.8%） had acute kidney injury during the treatment. Clinical pharmacists should actively participate in the clinical treatment of polymyxin B， formulate individualized treatment plans according to the guidelines/consensus and in combination with the patient’s condition and infection status to improve the rationality of clinical medication.

Nephrotoxicity caused by polymyxin in the treatment of drug-resistant Gram-negative bacterial infections：a meta-analysis / 中国药房

OBJECTIVE To evaluate the incidence of nephrotoxicity in patients with drug-resistant Gram-negative bacterial infections after the use of polymyxin， and to provide evidence-based reference for clinical rational drug use. METHODS PubMed， Embase， Web of Science， the Cochrane Library， Wanfang database， CNKI， VIP and SinoMed were searched to collect randomized controlled trials （RCTs） or cohort studies about the polymyxin （trial group） versus other antibiotics （control group） or polymyxin B （trial group） versus polymyxin E （control group）. After literature screening， data extraction and quality evaluation， RevMan 5.4.1 software was used for meta-analysis. RESULTS A total of 37 studies were included， including 4 RCTs and 33 cohort studies， with a total of 5 871 patients. The meta-analysis results showed that in RCT [RR＝2.64，95%CI （1.43，4.87），P＝0.002] and in cohort studies [RR＝1.59， 95%CI （1.27， 1.98）， P＜0.000 1]， the incidence of nephrotoxicity in the trial group was significantly higher than control group. The results of the subgroup analysis of cohort studies showed that the incidence of nephrotoxicity in the trial group （receiving polymyxin） was significantly higher than control group （receiving new β-lactam and β-lactamase inhibitors and tigecycline）； when Kidney Disease Improving Global Outcomes （KDIGO）， renal replacement therapy or 0.5 times increase in serum creatinine were used as the standard of nephrotoxicity， the incidence of nephrotoxicity in the trial group was significantly higher than the control group （P＜0.05）. The incidence of nephrotoxicity in patients receiving polymyxin E was significantly higher than those using polymyxin B [RR＝0.57， 95%CI （0.39，0.84）， P＝0.005]. CONCLUSIONS In the treatment of drug-resistant Gram-negative bacteria infections， the incidence of nephrotoxicity caused by polymyxin is relatively high. The TYU108F）； incidence of nephrotoxicity caused by polymyxin E is higher than polymyxin B.

Polymyxin resistance caused by large-scale genomic inversion due to IS26 intramolecular translocation in Klebsiella pneumoniae

Polymyxin B and polymyxin E (colistin) are presently considered the last line of defense against human infections caused by multidrug-resistant Gram-negative organisms such as carbapenemase-producer Enterobacterales, Acinetobacter baumannii, and Klebsiella pneumoniae. Yet resistance to this last-line drugs is a major public health threat and is rapidly increasing. Polymyxin S2 (S2) is a polymyxin B analogue previously synthesized in our institute with obviously high antibacterial activity and lower toxicity than polymyxin B and colistin. To predict the possible resistant mechanism of S2 for wide clinical application, we experimentally induced bacterial resistant mutants and studied the preliminary resistance mechanisms. Mut-S, a resistant mutant of K. pneumoniae ATCC BAA-2146 (Kpn2146) induced by S2, was analyzed by whole genome sequencing, transcriptomics, mass spectrometry and complementation experiment. Surprisingly, large-scale genomic inversion (LSGI) of approximately 1.1 Mbp in the chromosome caused by IS26 mediated intramolecular transposition was found in Mut-S, which led to mgrB truncation, lipid A modification and hence S2 resistance. The resistance can be complemented by plasmid carrying intact mgrB. The same mechanism was also found in polymyxin B and colistin induced drug-resistant mutants of Kpn2146 (Mut-B and Mut-E, respectively). This is the first report of polymyxin resistance caused by IS26 intramolecular transposition mediated mgrB truncation in chromosome in K. pneumoniae. The findings broaden our scope of knowledge for polymyxin resistance and enriched our understanding of how bacteria can manage to survive in the presence of antibiotics.

LPS adsorption and inflammation alleviation by polymyxin B-modified liposomes for atherosclerosis treatment

Chronic inflammation is critical in the onset and progression of atherosclerosis (AS). The lipopolysaccharide (LPS) level in the circulation system is elevated in AS patients and animal models, which is correlated with the severity of AS. Inspired by the underlying mechanism that LPS could drive the polarization of macrophages toward the M1 phenotype, aggravate inflammation, and ultimately contribute to the exacerbation of AS, LPS in the circulation system was supposed to be the therapeutic target for AS treatment. In the present study, polymyxin (PMB) covalently conjugated to PEGylated liposomes (PLPs) were formulated to adsorb LPS through specific interactions between PMB and LPS. In vitro, the experiments demonstrated that PLPs could adsorb LPS, reduce the polarization of macrophages to M1 phenotype and inhibit the formation of foam cells. In vivo, the study revealed that PLPs treatment reduced the serum levels of LPS and pro-inflammatory cytokines, decreased the proportion of M1-type macrophages in AS plaque, stabilized AS plaque, and downsized the plaque burdens in arteries, which eventually attenuated the progression of AS. Our study highlighted LPS in the circulation system as the therapeutic target for AS and provided an alternative strategy for AS treatment.

Rapid bacterial identification by MALDI-TOF MS directly from blood cultures and rapid susceptibility testing: A simple approach to reduce the turnaround time of blood cultures

Abstract Antimicrobial treatment of patients with bloodstream infections (BSI) is time-sensitive. In an era of increasing antimicrobial resistance, rapid detection and identification of bacteria with antimicrobial susceptibility are critical for targeted therapy early in the disease course. This study describes the performance of a rapid method for identifying and testing antimicrobial susceptibility of Gram-negative bacteria performed directly from blood culture bottles in a routine microbiology laboratory. A total of 284, 120, and 24 samples were analyzed by rapid identification (Rid), rapid susceptibility testing (RAST), and rapid broth microdilution for polymyxin B (rMIC), respectively, and compared with standard methods. Our protocol was able to identify 93% of isolates at the species level using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We obtained 100% agreement for RAST compared to the standard method and 96% agreement for rMIC. Our protocol has proven to be an excellent tool for rapid identification of Gram-negative bacilli causing BSIs. It can also be used in microbiology laboratory routine along with RAST and faster polymyxin microdilution, especially for carbapenemase-producing bacteria, allowing for rapid, simple, accurate, and cost-effective diagnosis.

Capacidade de formação de biofilmes e perfil de resistência de Acinetobacter baumannii isolados em unidades de terapia intensiva: uma revisão sistemática

Introdução: Acinetobacter baumanni é um cocobacilo Gram negativo responsável por elevadas taxas de infecções relacionadas à assistência à saúde (IRAS). Apresenta alto nível de resistência intrínseca a antimicrobianos, além da capacidade de adquirir resistência a carbapenêmicos e polimixinas. Ainda, A. baumannii possui habilidade para produzir biofilmes em superfícies abióticas e bióticas, o que favorece a infecção de pacientes gravemente enfermos internados em unidades de terapia intensiva (UTI). Deve ser ressaltado que bactérias envolvidas em biofilmes apresentam maior resistência aos antimicrobianos, atribuída a fatores bioqúmicos, moleculares e as condições dos hospedeiros, o que dificulta o tratamento dessas infecções. Objetivos: Avaliar a produção de biofilme por isolados de A. baumannii recuperados de pacientes internados em UTIs, bem como operfil de susceptibilidade a antimicrobianos (aminoglicosídeos, tigeciclina, carbapenêmicos e polimixinas) entre esses isolados. Métodos: Foi realizada uma revisão sistemática de acordo com os critérios Prisma nos bancos de dados Pubmed/Medline, Scopus, Lilacs, Scielo, e Web of Science. Resultados: Foram incluídos um total de 12 artigos que avaliaram 1006 isolados clínicos de A. baumannii, os quais todos foram resistentes aos carbapenê-micos. No entanto, a maioria dos isolados permaneceu sensível as polimixinas B e E(94,46%). A porcentagem dos isolados produtores de biofilme foi alta (96,3%), e neste estudo não fica clara a relação entre a habilidade de produzir biofilmes e a resistência aos antimicrobianos analisados. Conclusão: Mais estudos devem ser conduzidos para monitorar a resistência aos antimicrobianos em A. baumannii, sobretudo em produtores de biofilme, visto que o manejo terapêutico das infecções ocasionadas por essas linhagens torna-se mais complexo e desafiador.

SUMMARY Introduction: Acinetobacter baumanni is a Gram-negative coccobacillus responsible for high rates of healthcare-related infections (HAI). It has a high level of intrinsic resistance to antimicrobials, in addition to the ability to acquire resistance to carbapenems and polymyxins. Furthermore, A. baumannii has the ability to produce biofilms on abiotic and biotic surfaces, which favors the infection of critically ill patients admitted to intensive care units (ICU). It should be noted that bacteria involved in biofilms have greater resistance to antimicrobials, attributed to biochemical and molecular factors and the conditions of the hosts, which makes the treatment of these infections difficult. Objectives: To evaluate the biofilm production by A. baumannii isolates recovered from ICU patients, as well as the antimicrobial susceptibility profile (aminoglycosides, tigecycline, carbapenems and polymyxins) among these isolates. Methods: A systematic review was performed according to PRISMA criteria in the PUBMED/MEDLINE, Scopus, LILACS, SciELO, and Web of Science databases. Results: A total of 12 articles that evaluated 1006 clinical isolates of A. baumannii, all of which were resistant to carbapenems, were included. However, most isolates remained sensitive to polymyxins B and E (94.46%). The percentage of biofilm-producing isolates was high (96.3%), and in this study the relationship between the ability to produce biofilms and resistance to the analyzed antimicrobials is not clear. Conclusion: More studies should be conducted to monitor antimicrobial resistance in A. baumannii, especially in biofilm producers, as the therapeutic management of infections caused by these strains becomes more complex and challenging.

Introducción: Acinetobacter baumanni es un cocobacilo gramnegativo responsable de altas tasas de infecciones relacionadas con la salud. Tiene un alto nivel de resistencia intrínseca a los antimicrobianos, además de la capacidad de adquirir resistencia a los carbapenémicos y polimixinas. Además, A. baumannii tiene la capacidad de producir biopelículas en superficies abióticas y bióticas, lo que favorece la infección de pacientes críticos ingresados en unidades de cuidados intensivos (UCI). Cabe señalar que las bacterias involucradas en biofilms tienen mayor resistencia a los antimicrobianos, atribuida a factores bioquímicos y moleculares y a las condiciones de los hospedadores, lo que dificulta el tratamiento de estas infecciones. Objetivos: Evaluar la producción de biofilm por aislamientos de A. baumannii recuperados de pacientes de UCI, así como el perfil de susceptibilidad antimicrobiana (amino-glucósidos, tigeciclina, carbapenémicos y polimixinas) entre estos aislamientos. Métodos: Se realizó una revisión sistemática según los criterios Prisma en las bases de datos Pubmed / Medline, Scopus, Lilacs, SciELO y Web of Science. Resultados: Se incluyeron un total de 12 artículos que evaluaron 1006 aislamientos clínicos de A. baumannii, todos ellos resistentes a carbapenémicos. Sin embargo, la mayoría de los aislados permanecieron sensibles a las polimixinas B y E (94,46%). El porcentaje de aislamientos productores de biopelículas fue alto (96,3%), y en este estudio no está clara la relación entre la capacidad de producir biopelículas y la resistencia a los antimicrobianos analizados. Conclusión: Se deben realizar más estudios para monitorear la resistencia a los antimicrobianos en A. baumannii, especialmente en productores de biopelículas, ya que el manejo terapéutico de las infecciones causadas por estas cepas se vuelve más complejo y desafiante.

Polymyxin Acute Kidney Injury: a case of severe tubulopathy / Nefropatia por polimixina B: a tubulopatia pode ser muito séria!

Abstract Polymyxins are antibiotics developed in the 1950s. Polymyxin-induced neurotoxicity has been often described in medical literature. The same cannot be said of nephrotoxicity or tubulopathy in particular. This report describes the case of a patient prescribed polymyxin B to treat a surgical wound infection, which led to significant increases in fractional excretion of calcium, magnesium, and potassium and subsequent persistent decreases in the levels of these ions, with serious consequences for the patient. Severe hypocalcemia, hypomagnesemia, and hypokalemia may occur during treatment with polymyxin. Calcium, magnesium and potassium serum levels must be monitored during treatment to prevent life-threatening conditions.

Resumo Polimixinas são um grupo de antibióticos desenvolvidos na década de 1950. Seus efeitos neurotóxicos são comumente descritos na literatura, porém há menos relatos sobre seus efeitos nefrotóxicos, especialmente tubulopatias. O objetivo deste relato é descrever o uso de polimixina B em uma paciente para tratamento de infecção de ferida operatória, promovendo grande aumento das frações de excreção de cálcio, magnésio e potássio e acarretando reduções graves e persistentes desses íons, com sérias consequências para a paciente. Hipocalcemia, hipomagnesemia e hipocalemia severas podem ocorrer durante terapia com polimixina e é sugerido que sejam monitorizadas as concentrações séricas desses eletrólitos durante o tratamento como forma de evitar condições de risco à vida.