Application of multi-disciplinary team mode in prevention and control of multidrug resistant organism infection in lung transplant recipients / 器官移植

<b>Objective</b> To evaluate the effectiveness of multi-disciplinary team (MDT) mode in the prevention and control of multidrug resistant organism (MDRO) infection in lung transplant recipients. <b>Methods</b> Lung transplant recipients admitted to the hospital from 2019 to 2022 were enrolled. MDT expert group was established in January, 2020. A series of prevention and control measures were conducted. The implementation rate of MDRO prevention and control measures and the detection rate of MDRO on the environmental surface from 2020 to 2022, and the detection rate of MDRO in lung transplant recipients from 2019 to 2022 were analyzed. <b>Results</b> The overall implementation rate of MDRO prevention and control measures for medical staff was increased from 64.9% in 2020 to 91.6% in 2022, showing an increasing trend year by year (<i>P</i><0.05). The detection rate of MDRO on the environmental surface was decreased from 28% in 2020 to 9% in 2022, showing a downward trend year by year (<i>P</i><0.05). The detection rate of MDRO in lung transplant recipients was decreased from 66.7% in 2019 to 44.3% in 2022, showing a decreasing trend year by year (<i>P</i><0.001). <b>Conclusions</b> MDT mode management may enhance the implementation of MDRO prevention and control measures for medical staff, effectively reduce the infection rate of MDRO in lung transplant recipients and the detection rate of MDRO on the environmental surface, which is worthy of widespread application.

Study on the detection rate,epidemiology and resistance mechanism of MRSA in a hospital in recent 5 years / 国际检验医学杂志

Objective To investigate the detection rate,epidemiology and resistance mechanism of methicil-lin-resistant Staphylococcus aureus(MRSA)in a hospital in recent 5 years.Methods A total of 762 strains of non repetitive Staphylococcus aureus detected from 2016 to 2020 in a hospital were collected retrospectively.Methicillin-sensitive Staphylococcus aureus(MSSA)was 392 strains(MSSA group)and 370 strains caused by MRSA(MRSA group),and 95 strains of MRSA isolated in 2020 were further used for resistance mechanism.Staphylococcus aureus was identified and tested for drug sensitivity by Vitek 2 automatic microbial system.Molecular epidemiological typing was determined by multilocus sequence typing.The biofilm formation was performed by crystal violet staining.PCR amplification was used to detect drug resistance genes,virulence genes and biofilm related genes,and logistic regression analysis was used to investigate the independent risk factors of its occurrence.Results The detection rate of MRSA in past five years was 48.56％,mainly was from pus samples and secretion samples(38.38％,33.51％respectively).MRSA was found in the general sur-gery(18.65％)and otorhinolaryngology(12.70％).ST88 was the most common multilocus sequence typing(37.89％),and followed by ST951(24.21％).Moderate biofilm formation was the most common,accounting for 74.73％.Multivariate regression analysis showed that compared with MSSA group,hypoproteinemia,en-docrine system diseases,wound infection and history of antibiotic use within six months were the independent risk factors for infection in MRSA group.Compared with the control group,hospital transfer,wound infection and tumor were independent risk factors for infection in MRSA group(P＜0.05).Conclusion The detection rate of MRSA in a hospital is high,and the carrying rate of various drug-resistant genes is high.The hospital should pay attention to the prevalence of MRSA and related risk factors,so as to prevent it early.

Advances in Xpert MRSA/SA technology for colonisation and decolonisation of methicillin-anti staphylococcus aureus / 中国综合临床

Methicillin-anti staphylococcus aureus(MRSA) is one of the common pathogenic bacteria in hospital infection. Many asymptomatic MRSA carriers have been found in clinical practice, which can not only transmit the strain to others, but also cause secondary infection due to their own reasons. Decolonization measures can reduce the number of MRSA colonizers, thereby reducing the risk of endogenous infection and secondary transmission. Early identification is the first step to prevent transmission and secondary infection, which requires high accuracy and sensitivity of detection methods. Xpert MRSA/SA assay (Cepheid, Sunnyvale, CA, USA) may be a better choice, which can shorten the time of traditional methods, and has high specificity and sensitivity. Unlike other rapid detection methods, the Xpert MRSA/SA assay may be more suitable for MRSA colonisation detection.

Bactericidal Effect of Selenium Nanoparticles Combined with Povidone-iodine on Pathogenic Bacteria in Surgical Site Infection / 中山大学学报(医学科学版)

ObjectiveTo investigate the bactericidal effect of loaded multifunctional povidoneiodine-nanometer selenium （PVP-I@Se） disinfectant on Staphylococcus aureus （SA） and methicillin-resistant Staphylococcus aureus （MRSA）， and to provide an experimental basis for the reduction of surgical site infection （SSI）. MethodsThe control group was the povidone iodine （PVP-I） group with different concentrations of iodine （50， 75， 100， 200 and 400 μg/mL）. The PVP-I@Se group （experimental group） was the PVP-I group further supplemented with 2 μg/mL Selenium nanoparticles （SeNPs）. Then we compared the bactericidal effect of the two groups of disinfectant solutions on SA and MRSA by examining the minimum inhibitory concentration （MIC）， minimum bactericidal concentration （MBC）， the shortest sterilization time at a concentration of 50 μg/mL iodine and the inhibition zone diameters at concentrations of 200 μg/mL and 400 μg/mL iodine. ResultsMIC values of PVP-I against SA and MRSA were both 79.17 μg/mL， and those of PVP-I@Se were 54.17 and 70.83 μg/mL， respectively. MBC values of PVP-I against SA and MRSA were 129.17 and 150.00 μg/mL， respectively， and those of PVP-I@Se were 70.83 and 87.50 μg/mL， respectively. At a concentration of 50 μg/mL iodine， the shortest sterilization time of PVP-I for SA and MRSA was 130 s and 140 s， respectively， and that of PVP-I@Se was 65 s and 75 s， respectively. At a concentration of 200 μg/ml iodine， the inhibition zone diameters of PVP-I for SA and MRSA were 7.67 mm and 8.33 mm， and those of PVP-I@Se were both 9.50 mm. At a concentration of 400 μg/mL iodine， the inhibition zone diameters of PVP-I for SA and MRSA were 9.00 mm and 9.33 mm， and those of PVP-I@Se were 11.67 mm and 12.00 mm， respectively. ConclusionsPVP-I with different concentrations of 50， 75， 100， 200 and 400 μg/mL iodine supplemented with 2 μg/mL SeNPs have better and faster bactericidal effect on SA and MRSA. When combined with SeNPs， PVP-I can enhance the bactericidal activity against SA and MRSA， but with better sensitizing effect on SA than MRSA and higher demand of iodine concentration （400 μg/mL） for sensitizing effect on MRSA. This study provides a theoretical basis for selecting optimal concentration and action time of the disinfectant， thus reducing SSI.

Effects of the various herbs and different proportions of the herbs in Huidu Yinhua powder on methicillin-resistant Staphylococcus aureus / 中国比较医学杂志

Objective To study the inhibitory effect of Huidu Yinhua powder from the Orthodox Manual of External Medicine on methicillin-resistant Staphylococcus aureus(MRSA),virulence factor α-hemolysin(Hla)activity,and biofilm formation,and to explore the optimal ratios of Huidu Yinhua powder and provide experimental support for its use.Methods The inhibitory effects of Huidu Yinhua powder and the herbs in the formula on USA300 were analyzed by the minimum inhibitory concentration(MIC),minimum bactericidal concentration(MBC),and disk diffusion assay(K-B method).Hemolysis,neutralization,oligomerization,and Western blot assays were used to verify in which form the drug inhibits the activity of virulence factor α-hemolysin(Hla).A biofilm assay was performed to evaluate the inhibitory effect of Huidu Yinhua powder on biofilm.Orthogonal experiments were performed to explore the optimal ratio of Huidu Yinhua powder.Results Huidu Yinhua powder inhibited the MRSA strain with a MIC90 of 64 mg/mL and an MBC of 256 mg/mL with antibacterial circle diameter of(7.50±0.50)mm.Huidu Yinhua powder inhibited Hla activity by inhibiting Hla secretion.The minimum effective concentration(MEC)was 16 mg/mL,and the MEC of biofilm was 8 mg/mL.In Huidu Yinhua powder,honeysuckle and astragalus only affected the hemolytic activity of MRSA and biofilm formation without inhibiting bacterial growth.The hemolytic activity and biofilm of MEC were both 32 mg/mL.Glycyrrhiza had a strong bacterial inhibitory capacity with a MIC90 of 8 mg/mL and biofilm MEC of 1 mg/mL without showing inhibitory hemolytic activity at subinhibitory concentrations.The orthogonal experiment showed that,at a ratio of honeysuckle,astragalus,and glycyrrhiza in Huidu Yinhua powder of 1∶2∶4,the MIC90 was 16 mg/mL,MEC of hemolytic activity was 8 mg/mL and that of biofilm was 4 mg/mL,both of which were the lowest among the nine groups.Conclusions Huidu Yinhua powder affects the hemolytic activity and biofilm formation of MRSA at subinhibitory concentrations with the optimal ratio of honeysuckle,astragalus,and glycyrrhiza being 1∶2∶4.

El desarrollo y los complejos mecanismos de resistencia de S. aureus: una amenaza persistente en la era de los antibióticos

Introducción: S. aureus ha emergido como una amenaza persistente, demostrando una notable habilidad para desarrollar resistencia a lo largo de la evolución de los antibióticos. Desde los primeros enfrentamientos con la penicilina hasta los desafíos actuales con cepas resistentes a la vancomicina y la daptomicina, el estudio de los mecanismos de resistencia de este patógeno ha adquirido una importancia crítica. Objetivos: documentar los cambios en los patrones de resistencia de S. aureus a lo largo del tiempo, además de identificar las etapas críticas en el desarrollo de la resistencia a diferentes antibióticos. Materiales y métodos: el proceso de selección de artículos revisados se llevó a cabo identificando artículos publicados entre 2010 y 2023. Se utilizaron varias bases de datos relevantes, incluyendo PubMed, Scopus, Embase, Cochrane Library y Scielo. Se incluyeron estudios observacionales, artículos de revisión y guías clínicas. Se desarrollaron estrategias de búsqueda específicas para cada base de datos utilizando palabras clave y términos de búsqueda relacionados con S. aureus y su resistencia antimicrobiana, así como los tipos de estudios de interés. Se extrajeron datos relevantes de los estudios seleccionados, incluyendo información sobre los patrones de resistencia, mecanismos de resistencia, impacto clínico y estrategias terapéuticas. Los datos recopilados se analizaron y sintetizaron para documentar los cambios en los patrones de resistencia de S. aureus a lo largo del tiempo y para identificar las etapas críticas en el desarrollo de la resistencia a diferentes antibióticos. Resultados: se incluyeron 100 artículos donde se evidencia una evolución temporal de la resistencia, desde las primeras cepas resistentes a la penicilina hasta las actuales cepas resistentes a la vancomicina y la daptomicina. Estos estudios proporcionaron un análisis detallado de los mecanismos moleculares clave que impulsan la resistencia antimicrobiana, tales como la producción de beta-lactamasas, las alteraciones en las proteínas de unión a penicilina y las modificaciones en la membrana celular. Los hallazgos destacan una evolución significativa en la capacidad de S. aureus para adaptarse a diferentes antibióticos a lo largo del tiempo, subrayando la complejidad y la diversidad de los mecanismos de resistencia desarrollados por esta bacteria. Conclusiones: la evolución de la resistencia de S. aureus ha seguido un patrón marcado por etapas críticas, desde la aparición de cepas productoras de penicilinasa tras la introducción de la penicilina, hasta el surgimiento de MRSA con la meticilina y de VISA y VRSA con la vancomicina. Estos cambios destacan la capacidad de adaptación de S. aureus a nuevas presiones antibióticas. La revisión subraya la necesidad urgente de desarrollar estrategias antimicrobianas innovadoras y sostenibles para controlar esta creciente amenaza. Comprender los mecanismos de resistencia es crucial para desarrollar enfoques más efectivos y personalizados en el tratamiento de las infecciones por este germen.

Introduction: S. aureus has emerged as a persistent threat, demonstrating a remarkable ability to develop resistance throughout the evolution of antibiotics. From the first confrontations with penicillin to the current challenges with strains resistant to vancomycin and daptomycin, the study of the resistance mechanisms of this pathogen has acquired critical importance. Objectives: To document changes in S. aureus resistance patterns over time and identify critical stages in the development of resistance to different antibiotics. Materials and methods: The reviewed articles were selected by identifying articles published between 2010 and 2023. Several relevant databases were used, including PubMed, Scopus, Embase, Cochrane Library, and SciELO. Observational studies, review articles, and clinical guidelines were included. Specific search strategies were developed for each database using keywords and search terms related to S. aureus and its antimicrobial resistance as well as the types of studies of interest. Relevant data were extracted from the selected studies, including information on resistance patterns, resistance mechanisms, clinical impact, and therapeutic strategies. The collected data were analyzed and synthesized to document changes in S. aureus resistance patterns over time and identify critical stages in the development of resistance to different antibiotics. Results: One hundred articles were included where a temporal evolution of resistance is evident, from the first strains resistant to penicillin to the current strains resistant to vancomycin and daptomycin. These studies provided a detailed analysis of the key molecular mechanisms driving antimicrobial resistance, such as beta-lactamase production, alterations in penicillin-binding proteins, and cell membrane modifications. The findings highlight a significant evolution in the ability of S. aureus to adapt to different antibiotics over time, underscoring the complexity and diversity of resistance mechanisms developed by this bacterium. Conclusions: The evolution of S. aureus resistance has followed a pattern marked by critical stages, from the appearance of penicillinase-producing strains after the introduction of penicillin to the emergence of MRSA with methicillin and of VISA and VRSA with vancomycin. These changes highlight the ability of S. aureus to adapt to new antibiotic pressures. The review highlights the urgent need to develop innovative and sustainable antimicrobial strategies to control this growing threat. Understanding resistance mechanisms is crucial to developing more effective and personalized approaches for the treatment of infections caused by this germ.

Evaluation of diagnostic accuracy of latex agglutination test and E-test for the detection of methicillin-resistant Staphylococcus aureus

Background: This study was undertaken to compare the phenotypic methods of latex agglutination test and e-test with polymerase chain reaction for the detection of methicillin-resistant Staphylococcus aureus. Methods: Two hundred pus samples obtained from different clinical disciplines were subjected to the latex agglutination test and minimum inhibitory concentration by e-test (Oxacillin and Vancomycin) as per the standard guidelines. The comparison was made with polymerase chain reaction as the reference test. The diagnostic accuracy of each method was reported in terms of sensitivity, specificity, positive predictive value, and negative predictive value. Results: The sensitivity of latex agglutination test was found to be 100% whereas e-test for Oxacillin was found to be 96.67% sensitive. Higher specificity for e-test was reported (99.41%) when compared to the latex agglutination test (97.65%). Conclusions: Latex agglutination and e-tests are tests are relatively simpler, rapid, and easy-to-perform methods when compared to polymerase chain reaction. The present study reported high sensitivity and specificity values for both the tests, and therefore supports usage of the stated methods as screening tools for methicillin-resistant S. aureus. However, more multi-centric studies are recommended to precisely determine the diagnostic accuracy of these phenotypic methods.

Síndrome de compresión medular de etiología infecciosa

El síndrome de compresión medular es una urgencia neuroquirúrgica debido a que un diagnóstico precoz y un tratamiento temprano podría revertir las incapacitantes secuelas ocasionadas por esta enfermedad. Las causas de este síndrome pueden ser traumática, metastásica, infecciosa y vascular (hematomas). La etiología infecciosa no es frecuente y el principal germen involucrado suele ser Staphylococcus aureus. A continuación presentamos el caso de una paciente de 58 años con síndrome de compresión medular de etiología infecciosa quien fue ingresada en el Servicio de Clínica Médica del Centro Médico Nacional.

Spinal cord compression syndrome is a neurosurgical emergency because early diagnosis and early treatment could reverse the disabling consequences caused by this disease. The causes of this syndrome can be traumatic, metastatic, infectious, and vascular (hematomas). Infectious etiology is not frequent and the main germ involved is usually Staphylococcus aureus. Below we present the case of a 58-year-old patient with spinal cord compression syndrome of infectious etiology who was admitted to the Medical Clinic Service of the National Medical Center.

A study of microbial pattern and antibiotic susceptibility in blood cultures among children aged upto thirty six months

Background: Sepsis is the most common cause of high morbidity and mortality among newborn, infants and young children. The organisms implicated in these infections vary with geographical alteration.so antibiotics used should be decided by local prevalence of microbial pathogen, and its bacterial susceptibility pattern. Methods: a prospective observational study among the different neonates and children aged 0 to 36 months. Blood samples are taken under aseptic precaution. Inocluted onto blood culture media (brain heart infusion broth). It is incubated at 37°C. Turbidity is observed daily and it is sub cultured on alternate days. If there is growth, the organism is identified by routine biochemical reactions and the antibiotic susceptibility test was done on the Muller Hinton agar using appropriate antibiotic discs. For testing antibiotic susceptibility, criteria defined by the clinical and laboratory standards institute (CLSI) were followed. Results: Among 148 subjects 102 found to be culture positive with positive rate of 69%. Gram negative organism is more prevalence in this study, most common isolates from gram negative sepsis was Klebsilla species (22.2%) followed by E. coli (18.1%). Conclusions: Gram negative organism form the majority of isolates in our setup with Klebsilla as the most common species among them, which was least sensitive to most of the drugs. Among gram positive organism MRSA as the most common isolates in our setup. Most of the antibiotic were sensitive. Limited and objective use of antibiotic therapy is a much-needed statergy and the new guidelines.

Prevalencia de colonización nasal por Staphylococcus aureus meticilino resistente en estudiantes de medicina de la Pontificia Universidad Católica de Chile: comparación entre estudiantes no expuestos a la clínica (pre-clínicos) y clínicos / Prevalence of nasal colonization by methicillin-resistant Staphylococcus aureus in medical students in Chile: comparison between pre-clinical and clinical environment

OBJETIVOS: El objetivo primario de este estudio fue determinar la prevalencia de colonización nasal por Staphylococcus aureus meticilino resistente (SAMR) en estudiantes de medicina en cursos pre-clínicos versus clínicos de la Pontificia Universidad Católica de Chile y describir el patrón epidemiológico, clínico y molecular de las cepas de SAMR obtenidas. PACIENTES Y MÉTODO: Se realizó un estudio descriptivo transversal a 299 estudiantes de pregrado y postgrado de medicina de la Pontificia Universidad Católica de Chile, 44 alumnos de primer año y 29 de segundo año, correspondiendo éstos a alumnos de cursos sin exposición clínica habitual y 26 alumnos de sexto año, 58 de séptimo año y 142 residentes, los cuales están diariamente expuestos a ambientes hospitalarios. RESULTADOS: Se encontró una portación de 0% (0/73) en estudiantes no expuestos a la clínica (cursos pre-clínicos) y de 0,9% (2/226) en estudiantes de cursos clínicos, diferencia que no fue estadísticamente significativa (valor p 0,42). CONCLUSIONES: La portación nasal de SAMR en el personal de salud de este trabajo fue baja, encontrando muestras positivas solo en estudiantes con exposición clínica. Esta prevalencia es similar a la reportada en otros trabajos de características similares realizados en Chile.

OBJECTIVES: The primary objective of this study was to determine the prevalence of nasal colonization of methicillin resistant Staphylococcus aureus (MRSA) in medical students in pre-clinical versus clinical courses at the Pontificia Universidad Católica de Chile and to describe the epidemiological, clinical and molecular pattern of the MRSA strains obtained. METHOD: A cross-sectional descriptive study was carried out on 299 undergraduate and graduate medical students from the Pontificia Universidad Católica de Chile, 44 first-year students and 29 second-year students, corresponding to students of courses without regular clinical exposure and 26 sixth-year students, 58 seventh-year and 142 residents, who are daily exposed to hospital environments. RESULTS: A carriage of 0% (0/73) was found in students not exposed to the clinic (pre-clinical courses) and 0.9% (2/226) in students of clinical courses, a difference that was not statistically significant (p-value 0.42). CONCLUSIONS: The MRSA nasal carriage found in our medical students was low, finding positive samples only in students with clinical exposure. This prevalence is similar to the one reported in other studies in Chile with similar characteristics.

MINIMUM INHIBITORY CONCENTRATION LEVELS OF MUPIROCIN BY E-TEST AMONG STAPHYLOCOCCUS AUREUS ISOLATES AND THEIR ANTIMICROBIAL SUSCEPTIBILITY PATTERN

Objective: This study was done to evaluate the susceptibility of Staphylococcus aureus to mupirocin and to determine the antimicrobial susceptibility pattern of Staphylococcus aureus among various clinical isolates.Methods: All the consecutive, non-duplicative Staphylococcus aureus isolates collected during the year 2020 were subjected to the disk diffusion method to evaluate the antimicrobial susceptibility pattern and were stocked. Mupirocin susceptibility for all stocked Staphylococcus aureus was detected by Minimal inhibitory concentration (MIC) determination by Epsilometer test (E-test).Results: The total number of Staphylococcus aureus was 52. The maximum number of Staphylococcus aureus was isolated from pus sample 40 (76.9%). Among the 52 isolates, 26 (50%) were found to be methicillin-resistant Staphylococcus aureus (MRSA). All the isolates were susceptible to tetracycline (100%), vancomycin (100%), teicoplanin (100%), and linezolid (100%). By E-test, the overall prevalence of mupirocin resistance was 63.5%. Low-level Mupirocin resistance (MupRL) of 8-256 µg/ml was 59.6% and high-level mupirocin resistance (MupRH) of ?512 µg/ml was 3.9%.Conclusion: The present study shows a high prevalence of mupirocin resistance (63.5%) which is a serious concern. Therefore, indiscriminate use of topical mupirocin in carriers is not advisable. It may be recommended only in case of an outbreak of skin and soft tissue infection attributed to Staphylococcus aureus.

Piomiositis en pediatría: experiencia de 10 años en un hospital pediátrico de alta complejidad en Argentina / Pyomyositis in pediatrics: 10-year experience in a high-complexity pediatric hospital in Argentina

INTRODUCCIÓN: La piomiositis es una infección bacteriana agudasubaguda del músculo esquelético. OBJETIVO: Estimar la incidencia de piomiositis en pacientes internados, describir e identificar factores de riesgo para bacteriemia y hospitalización, y evaluar diferencias entre Staphylococccus aureus sensible y resistente a meticilina (SASM y SARM). PACIENTES Y MÉTODOS: Estudio descriptivo, retrospectivo, observacional, con pacientes de 1 mes a 18 años de edad, internados entre el 1 de enero de 2008 y 31 de diciembre de 2018. Variables: sexo, edad, hacinamiento en el hogar, existencia de lesión previa, estacionalidad, localización anatómica e imágenes, antibioterapia previa, estadio clínico, parámetros de laboratorio, cultivos y antibiograma, días de tratamiento intravenoso (IV), de internación, de fiebre y bacteriemia. RESULTADOS: Se incluyeron 188 pacientes. Incidencia: 38,9 casos / 10.000 admisiones (IC95 % 33,7 - 44,9). Días de internación y tratamiento IV: 11 (RQ 8-15 y RQ 8-14, respectivamente). El desarrollo de bacteriemia se asoció a PCR elevada (p = 0,03) y fiebre prolongada (p < 0,001). No hubo diferencias en la evolución y parámetros de laboratorio entre SASM y SARM. La leucocitosis (p = 0,004), neutrofilia (p = 0,005) y bacteriemia (p = 0,001) se asociaron a mayor estadía hospitalaria. CONCLUSIONES: Este estudio recaba la experiencia de más de 10 años de niños internados con diagnóstico de piomiositis y proporciona información sobre sus características. Se describen parámetros asociados a bacteriemia y estadía hospitalaria.

BACKGROUND: Pyomyositis is an acute-subacute bacterial infection of skeletal muscle. AIM: To estimate the incidence of pyomyositis in hospitalized patients, describe and identify risk factors for bacteremia and hospitalization, and evaluate differences between MSSA and MRSA. METHODS: Descriptive, retrospective, observational study with patients aged 1 month to 18 years hospitalized between January, 1, 2008 and December 1, 2018. Variables: sex, age, home overcrowding, previous injury, seasonality, anatomical location and images, previous antibiotherapy, clinical stage, laboratory, cultures and antibiogram, days of intravenous (IV) treatment, hospitalization, fever and bacteremia. RESULTS: 188 patients were included. Incidence: 38.9 cases/10,000 admissions (95% CI 33.7 - 44.9). Days of hospitalization and IV treatment: 11 (RQ 8-15 and RQ 8-14, respectively). The development of bacteremia was associated with elevated CRP (p = 0.03) and prolonged fever (p < 0.001). There were no differences in the evolution and laboratory parameters between MSSA and MRSA. Leukocytosis (p = 0.004), neutrophilia (p = 0.005), and bacteremia (p = 0.001) were associated with a longer hospital stay. CONCLUSIONS: This study collects the experience of more than 10 years of hospitalized children diagnosed with pyomyositis and provides information on its characteristics. Parameters associated with bacteremia and hospital stay are described.

Analysis of clinical and imaging features of air-borne and blood-borne Staphylococcus aureus pneumonia in children / 中国小儿急救医学

Objective:To compare the clinical and imaging features of air-borne and blood-borne Staphylococcus aureus pneumonia(SAP) in children.Methods:The clinical data of 54 children with SAP from 2015 to 2020 at Shengjing Hospital of China Medical University were retrospectively analyzed, including 28 cases in air-borne group and 26 cases in blood-borne group.The general data, clinical manifestations, laboratory tests and imaging data of the patients in two groups were compared.Results:There were no significant differences in age, sex and onset season between air-borne group and blood-borne group( P>0.05). The incidences of cough, dyspnea and lung rale in air-borne group were significantly higher than those in blood-borne group( P<0.05). Air-borne group was often complicated with acute respiratory distress syndrome and respiratory failure, but extrapulmonary infection was rare.The symptoms and signs of respiratory tract in patients from the blood-borne group were not obvious, and more complicated with other parts or systemic infection and poisoning symptoms, such as septic shock, skin and soft tissue infection, osteomyelitis, etc.The patients with leukocyte decrease(<4.0×10 9/L) in blood-borne group were more than those patients from air-borne group.The median values of C-reactive protein, procalcitonin and interleukin -6 in blood-borne group were higher than those in air-borne group, but there were no statistical differences( P>0.05). On imaging, the incidences of massive pulmonary exudation and consolidation in air-borne SAP were higher, while the incidences of pulmonary nodules and air sacs in blood-borne SAP were higher( P<0.05). Conclusion:The clinical and imaging manifestations of air-borne SAP and blood-borne SAP are different.Respiratory symptoms of air-borne SAP are prominent, however, systemic poisoning symptoms of blood-borne SAP are severe.As for imaging, air-borne SAP is more prone to large lung consolidation, while blood-borne SAP is more prone to lung nodules and air bags.

Memantine hydrochloride promotes the antibacterial effect of neutrophils against methicillin-resistant Staphylococcus aureus and the related mechanism / 中华微生物学和免疫学杂志

Objective:To investigate whether memantine hydrochloride (MEM) could promote the bactericidal effect of neutrophils against methicillin-resistant Staphylococcus aureus (MRSA) and the possible mechanism. Methods:Neutrophils were co-incubated with different concentrations of MEM and MRSA for 4 h. Then the cell lysates were collected and cultured on plate for survival bacteria counting. After co-incubation, the neutrophils were collected to detect the production of reactive oxygen species (ROS) and the release of neutrophil extracellular traps (NETs). A mouse model of MRSA infection was established, and then the mice were treated with or without MEM. Blood, spleen and kidney samples were collected from the mice for bacterial colony counting and blood procalcitonin (PCT) detection. In the 48 h survival experiment, the mice were first infected with MRSA, and then treated with MEM or PBS. The survival rates of the mice were calculated and the survival curves were drawn.Results:The number of MRSA co-cultured with neutrophils decreased significantly in the presence of MEM, and within a certain concentration range, the survival number of MRSA decreased with the increase of MEM concentration. Moreover, MEM could significantly promote the production of ROS by neutrophils and the formation of NETs. In vivo experiment showed that the concentration of PCT in mouse blood samples was lower in the MRSA+ MEM group than in the MRSA+ PBS group. The animal experiment also revealed that MEM significantly decreased the bacteria loads in mouse blood and organs and increased the 48 h survival rate after MRSA infection.Conclusions:MEM could significantly promote the bactericidal effect of neutrophils against MRSA, which might be related to the enhanced generation of ROS by neutrophils and the formation of NETs.

Feasibility study on rapid identification of methicillin-resistant Staphylococcus aureus by different algorithms of MALDI-TOF mass spectrometry / 中华检验医学杂志

Objective:To explore the feasibility of rapid identification of methicillin-resistant Staphylococcus aureus using different algorithms of the matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometer. Methods:Totally 314 clinical isolates of Staphylococcus aureus were selected from the bacterial bank at Beijing Tongren Hospital from January 2017 to June 2019. The samples were identified by MALDI-TOF MS, and screened by cefoxitin disk method (inhibition ring diameter ￡21 mm) and PCR mecA gene. The strains were divided into a methicillin-resistant Staphylococcus aureus (MRSA) group (130 strains) and a methicillin-susceptible Staphylococcus aureus (MSSA) group (184 strains). Then, after collecting the spectrograms of these samples using formic acid extraction, the MRSA group and MSSA group were divided into three subgroups each, namely MRSA-1 (43 strains), MRSA-2 (42 strains), MRSA-3 (45 strains) and MSSA-1 (60 strains), MSSA-2 (61 strains) and MSSA-3 (63 strains). The groups were studied using genetic algorithm (GA), fast classification algorithm (QC) and supervised neural network algorithm (SNN) in the ClinProTools software on the Bruker MALDI-TOF mass spectrometer, and the convolutional neural network algorithm (CNN) in the Ex-SmartSpec software on the Zhongyuan Hui-Ji mass spectrometer. These studies were repeated for 3 rounds. The first round with MRSA-1 and MRSA-2, MSSA-1 and MSSA-2 being model groups, MRSA-3 and MSSA-3 being validation groups. The validation groups were rotated for each round. The areas under the receiver operating characteristic (ROC) curve expansions of the four algorithms were used to confirm each program′s performance. Then, 38 MRSA strains and 40 MSSA clinical strains were selected from the bacterial bank of the Laboratory of Beijing Tongren Hospital from July 2019 to December 2019, and were put through the formic acid extraction method to collect their spectra. These samples were tested independently with their convolutional neural network models. Results:After three rounds of modeling and verification, the areas under the ROC curves of the three Bruker ClinProTools programs were as follows: for genetic algorithm, the areas were 0.89, 0.74, and 0.64 respectively; for fast classification algorithm, the areas were 0.77, 0.95, and 0.94 respectively; and for supervised neural network algorithm, the areas were 0.90, 0.98, and 0.98 respectively. The areas under the ROC curves of the convolutional neural network algorithm with Zhongyuan Huiji mass spectrometer′s Ex-SmartSpec software were 0.95, 0.99, and 0.99 respectively. The independent test results of convolutional neural network algorithm showed that these results have an accuracy, specificity, sensitivity and AUC of 88.82% (810/912), 81.15% (779/960), 84.88% (1 589/1 872) and 0.92 respectively.Conclusions:The supervised neural network algorithm of Bruker′s ClinProTools and the convolutional neural network algorithm of Zhongyuan Hui-Ji mass spectrometer′s EX-Smartspec is clinically acceptable for rapid identification of MRSA performance indicators. Using convolutional neural network algorithm and MALDI-TOF mass spectrometry, MRSA strains can be identified quickly, providing timely advice for clinical medications.

In vitro efficacy and combined drug sensitivity of lycosin-I against methicillin-resistant Staphylococcus aureus / 中华检验医学杂志

Objective:The aim of this study was to evaluate the in vitro activity of lysosin-Ⅰ against Methicillin-resistant Staphylococcus aureus (MRSA) and its synergistic effect with eight common antibacterial drugs against MRSA. Methods:This study was conducted following the design principles of a randomized controlled trials. Ten MRSA isolates, clinically isolated from the Second Xiangya Hospital of Central South University between September and November 2021, were determined the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and bactericidal kinetic test of lycosin-Ⅰ in vitro anti-MRSA by micro-broth dilution method. Additionally, the micro-broth chessboard dilution method was utilized to evaluate the in vitro efficacy of lycosin-Ⅰ in combination with eight common antimicrobial agants, including penicillin, erythromycin, levofloxacin, gentamicin, rifampicin, minocycline, vancomycin, and linezolid. Results:The MIC range of lycosin-Ⅰ against MRSA was found to be between 4-8 mg/L with the MIC 50 and MIC 90 were 4 mg/L and 8 mg/L, respectively. The range of MBC was also between 4-8 mg/L, and the ratio of MBC/MIC was 1-2. The bactericidal kinetics test revealed that the number of surviving MRSA clinical isolates and standard strains initially decreased rapidly but then showed a resurgence when the concentration of lycosin-Ⅰ was 1/2 MIC or MIC. While, the bacterial load gradually reduced until complete elimination when the concentration was at 2 MIC or 4 MIC. The combination of lycosin-Ⅰ and gentamicin exhibited mainly synergistic effects, while the combination with other antibiotics showed mainly additive effects. Moreover, the combination of lycosin-Ⅰ and antibacterial drugs can significantly reduce the MIC 50 and MIC 90 of antibiotics. Conclusion:lycosin-Ⅰ has great antibacterial and bactericidal activity against MRSA in vitro with rapid and thorough sterilization effect and it can play a synergistic or additive role when combined with other antibacterial drugs against MRSA in vitro.

Molecular epidemiology progress of community-associated Methicillin-resistant Staphylococcus aureus infection in children / 中华实用儿科临床杂志

Antimicrobial resistance of Staphylococcus aureus is a main factor for the poor prognosis.In China, the detection rate of Methicillin-resistant Staphylococcus aureus (MRSA) in children is annually increasing, especially the community-acquired MRSA (CA-MRSA). This review discussed molecular characteristics, antimicrobial resistance mechanism and antimicrobial resistance progress of CA-MRSA, and analyzed recent molecular epidemiology and changes of drug resistance to CA-MRSA in children from China, thus providing theoretical basis for the prevention and control of CA-MRSA in children.

Frecuencia del gen mecA en Staphylococcus aureus meticilinorresistente en un hospital de tercer nivel en Perú

Objetivos: determinar la frecuencia del gen mecA en Staphylococcus aureus resistente a meticilina (MRSA) aislados de pacientes atendidos en un hospital de tercer nivel en la región Cajamarca, Perú; asimismo, determinar cuál de los dos antibióticos usados como screening fenotípico tiene mayor utilidad para explicar la presencia de dicho gen. Métodos: se analizaron 71 aislamientos bacterianos provenientes de muestras del Hospital Regional Docente de Cajamarca, la identificación de S. aureus se llevó a cabo mediante el equipo MicroScan. El screening fenotípico para resistencia a meticilina se realizó mediante la técnica de difusión, con discos de cefoxitina y oxacilina. La extracción de ADN se realizó mediante shock térmico, la detección del gen mecA se realizó mediante reacción en cadena de la polimerasa. El análisis estadístico se realizó con el software SPSS v.25. Resultados: de los 71 aislados, 40 (56,3%) fueron MRSA portadores del gen mecA, la mayoría de estos aislamientos correspondieron a pacientes hospitalizados 22 (31,0%), siendo más frecuentes en muestras de secreción bronquial 27 (38,0%). El screening fenotípico con disco de cefoxitina predijo mejor la presencia del gen mecA [P=0,010; Exp(B)= 12,3] en comparación con el disco de oxacilina. Conclusiones: este estudio demostró alta frecuencia de MRSA mecA positivo en muestras de origen clínico, principalmente de pacientes hospitalizados. Es importante establecer medidas de vigilancia para identificar MRSA en todos los hospitales de la región.

Objective: to determine the frequency of the mecA gene in methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients treated at a third-level hospital in the Cajamarca region, Peru; as well as, to determine which of the two antibiotics used as phenotypic screening is more useful in explaining the presence of said gene. Methods: 71 bacterial isolates were analyzed from samples obtained from the Hospital Regional Docente of Cajamarca. The identification of S. aureus was carried out using the MicroScan system. Phenotypic screening for resistance to methicillin was performed using the diffusion technique with cefoxitin and oxacillin discs. DNA extraction was performed by heat shock, mecA gene detection was performed through polymerase chain reaction. For data analysis, the statistical software SPSS v.25 was used. Results: from 71 isolates, 40 (56,3%) were MRSA carriers of the mecA gene, the majority of these isolates corresponded to hospitalized patients 22 (31,0%), being more frequent in bronchial secretion samples 27 (38,0%). Phenotypic screening with cefoxitin disc was a better predictor for the presence of the mecA gene [P=0,010; Exp(B)= 12,3] compared to the oxacillin disc. Conclusions: It is shown a high frequency of positive MRSA mecA in samples of clinical origin, mainly from hospitalized patients. It is important to establish surveillance guidelines to identify MRSA in all hospitals in the region.

Tratamiento de las infecciones hospitalarias por staphylococcus aureus meticilino resistente / Treatment of hospital-acquired methicillin-resistant staphylococcus aureus infections / Tratamento de infecções por Staphylococcus aureus resistentes à meticilina, adquiridas em hospitais

Introducción: la infección por Staphylococcus aureus meticilino resistente, una de las principales bacterias causantes de infecciones hospitalarias, se ha convertido en una preocupación mundial dada la alta tasa de morbilidad y mortalidad que produce. La resistencia bacteriana es un factor que agrava la problemática de infecciones hospitalarias y se asocia fundamentalmente al uso inadecuado de antibióticos. El uso prudente de los mismos ayuda a controlar la resistencia bacteriana, sin embargo, cada vez se detectan más cepas resistentes a diversos antibióticos. Se realiza una revisión de tratamientos antibióticos disponibles para las infecciones hospitalarias producidas por Staphylococcus aureus meticilino resistente en paciente adulto, con la finalidad de proporcionar una guía sobre los mismos, que permita un uso racional de los antibióticos disponibles evitando así que se continúe desarrollando el fenómeno de resistencia bacteriana. Metodología: se realizó un estudio observacional, descriptivo, de tipo revisión literaria, restringiéndose la búsqueda a guías de práctica clínica. Para conocer las guías existentes en Uruguay se consultó la Cátedra de Enfermedades Infecciosas de la Facultad de Medicina, Universidad de la República y en el Ministerio de Salud Pública. Se encontraron y analizaron guías de diferentes países. Existe acuerdo en los lineamientos generales del tratamiento farmacológico de las infecciones hospitalarias por Staphylococcus aureus meticilino resistente. Resultados: en Uruguay no existen guías propias de tratamiento de las infecciones hospitalarias por Staphylococcus aureus meticilino resistente. Se utiliza como referencia la guía publicada por la Infectious Diseases Society of America. Discusión: algunos de los antibióticos recomendados en las guías analizadas no se encuentran disponibles en nuestro país, como es el caso de daptomicina, telavancina y cloxacilina. En particular, el no disponer de daptomicina podría llegar a dificultar el tratamiento de infecciones en las cuales la CIM de vancomicina sea mayor a 1.5 mg/L. Conclusiones: por lo tanto, se considera conveniente y necesario pautar el tratamiento de dichas infecciones, acorde a las posibilidades, a la epidemiología de nuestro país y a los patrones de resistencia a ésta bacteria, para unificar la práctica clínica y hacer un uso racional de los antibióticos de manera de evitar promover el fenómeno de resistencia microbiana.

Introduction: infection by methicillin-resistant Staphylococcus aureus, one of the main bacteria causing hospital infections, has become a worldwide concern due to the high morbidity and mortality rate it produces. Bacterial resistance is a factor that aggravates the problem of hospital infections and is mainly associated with the inappropriate use of antibiotics. The prudent use of antibiotics helps to control bacterial resistance; however, more and more strains resistant to different antibiotics are being detected. A review of available antibiotic treatments for hospital infections caused by methicillin-resistant Staphylococcus aureus in adult patients was carried out in order to provide a guide for a rational use of available antibiotics, thus avoiding further development of the phenomenon of bacterial resistance. Methodology: an observational, descriptive, literature review type study was carried out, restricting the search to clinical practice guidelines. In order to know the existing guidelines in Uruguay, the Department of Infectious Diseases of the School of Medicine, University of the Republic and the Ministry of Public Health were consulted. Guidelines from different countries were found and analyzed. There is agreement on the general guidelines for pharmacological treatment of hospital infections caused by methicillin-resistant Staphylococcus aureus. Results: in Uruguay there are no guidelines for the treatment of hospital infections caused by methicillin-resistant Staphylococcus aureus. The guidelines published by the Infectious Diseases Society of America are used as a reference. Discussion: some of the antibiotics recommended in the guidelines analyzed are not available in our country, as is the case of daptomycin, telavancin and cloxacillin. In particular, the unavailability of daptomycin could make the treatment of infections in which the MIC of vancomycin is higher than 1.5 mg/L more difficult. Conclusions: therefore, it is considered convenient and necessary to establish guidelines for the treatment of such infections, according to the possibilities, to the epidemiology of our country and to the resistance patterns to this bacterium, in order to unify clinical practice and make a rational use of antibiotics so as to avoid promoting the phenomenon of microbial resistance.

Introdução: a infecção por Staphylococcus aureus resistente à meticilina, uma das principais bactérias causadoras de infecções hospitalares, tornou-se uma preocupação mundial devido à alta taxa de morbidade e mortalidade que ela causa. A resistência bacteriana é um fator que agrava o problema das infecções adquiridas nos hospitais e está principalmente associada ao uso inadequado de antibióticos. O uso prudente de antibióticos ajuda a controlar a resistência bacteriana, entretanto, cada vez mais estirpes resistentes a vários antibióticos estão sendo detectadas. É realizada uma revisão dos tratamentos antibióticos disponíveis para infecções hospitalares causadas por Staphylococcus aureus resistente à meticilina em pacientes adultos, com o objetivo de fornecer um guia para o uso racional dos antibióticos disponíveis, evitando assim o desenvolvimento posterior do fenômeno de resistência bacteriana. Metodologia: foi realizado um estudo observacional, descritivo, do tipo revisão de literatura, restringindo a busca às diretrizes da prática clínica. O Departamento de Doenças Infecciosas da Faculdade de Medicina da Universidade da República e o Ministério da Saúde Pública foram consultados para as diretrizes existentes no Uruguai. Foram encontradas e analisadas diretrizes de diferentes países. Há acordo sobre as diretrizes gerais para o tratamento farmacológico de infecções hospitalares causadas por Staphylococcus aureus resistente à meticilina. Resultados: no Uruguai não há diretrizes para o tratamento de infecções por Staphylococcus aureus resistentes à meticilina adquiridas em hospitais. As diretrizes publicadas pela Sociedade de Doenças Infecciosas da América são usadas como referência. Discussão: alguns dos antibióticos recomendados nas diretrizes analisadas não estão disponíveis na Espanha, tais como daptomicina, telavancina e cloxacilina. Em particular, a indisponibilidade da daptomicina poderia dificultar o tratamento de infecções nas quais a MIC da vancomicina é maior que 1,5 mg/L. Conclusões: portanto, considera-se conveniente e necessário estabelecer diretrizes de tratamento para estas infecções, de acordo com as possibilidades, a epidemiologia de nosso país e os padrões de resistência a esta bactéria, a fim de unificar a prática clínica e fazer uso racional dos antibióticos, a fim de evitar a promoção do fenômeno da resistência microbiana.

Characterization and antimicrobial susceptibility of coagulase-positive Staphylococcus isolated in a veterinary teaching hospital in Chile / Caracterización y sensibilidad antimicrobiana de Staphylococcus coagulasa-positivos aislados en un hospital clínico veterinario en Chile

Abstract There is limited information about the prevalence and antimicrobial susceptibility of coagulase-positive Staphylococcus (CoPS) strains in veterinary settings in Chile. The aim of this observational study was to identify and characterize CoPS strains from dogs, owners, veterinary professionals and surfaces in a veterinary teaching hospital at Universidad de Chile to determine the presence of methicillin-resistant strains and evaluate the genetic relationship among the strains. Veterinarians (n = 24), surfaces (n = 10), and healthy dogs (n = 40) and their respective owners (n = 40) were sampled for CoPS. Isolates were identified by PCRand antimicrobial susceptibility was assessed by the disk diffusion method and MIC. The presence of the mecA gene was evaluated by PCR, and the genetic relationship among the strains was established by PFGE. A total of 45 CoPS strains were obtained, eight from veterinary professionals, three from hospital surfaces, eight from owners and 26 from dogs. Nine of the strains were resistant to methicillin (20%), and all of them carried the mecA gene. A high percentage of the strains was resistant to clindamycin (33.3%). Additionally, the isolated CoPS showed high genetic diversity. This study suggests that veterinarians are in high risk of harboring methicillin-resistant CoPS (25% versus 2.5% from owners) and our results provide evidence that clindamycin could not be an empiric alternative for CoPS in the analyzed hospital. This is the first report of methicillin-resistant CoPS in veterinary settings in Chile, considering humans, pets and surfaces.

Resumen Existe información limitada sobre prevalencia y sensibilidad antimicrobiana de cepas de Staphylococcus coagulasa-positivas (CoPS) en entornos veterinarios en Chile. El objetivo de este estudio observacional fue identificar y caracterizar cepas CoPS de perros, duenos, veterinarios y superficies de un hospital veterinario de la Universidad de Chile, determinar la presencia de cepas meticilino-resistentes y evaluar la relación genética entre las cepas. Se colectaron muestras de veterinarios (n = 24), de superficies hospitalarias (n = 10) y de perros sanos (n =40) y sus respectivos duenos (n = 40). Los aislamientos se identificaron mediante PCR y la sensibilidad antimicrobiana se evaluó por difusión en discos y CIM. También se empleó PCR para detectar la presencia del gen mecA; la relación genética entre las cepas se estableció mediante electroforesis de campos pulsantes (PFGE). Se obtuvo un total de 45 cepas de CoPS, 8 de veterinarios, 3 de superficies hospitalarias, 8 de duenos y 26 de perros. Nueve cepas fueron meticilino-resistentes (20%), todas portadoras del gen mecA. Un porcentaje importante de cepas fue resistente a clindamicina (33,3%). Además, las cepas aisladas mostraron una alta diversidad genética. Este estudio sugiere que los veterinarios tienen alto riesgo de portar CoPS resistentes a meticilina (25% versus 2,5% propietarios). Asimismo, nuestros resultados proporcionan evidencia de que la clindamicina podría no ser una alternativa empírica para CoPS en el hospital analizado. Este es el primer estudio de CoPS meticilino-resistentes en entornos veterinarios en Chile que considera humanos, mascotas y superficies.