Effects of overexpression of carbapenem OXA-48 on drug resistance,adaptability of bacterial strain and Toll-like receptor signaling pathway of host cell / 中国生物制品学杂志

@#Objective To investigate the effects of overexpression of OXA-48 on drug resistance,adaptability of bacterial strain and Toll-like receptor(TLR)signaling pathway of host cells. Methods The recombinant plasmid pET32a(+)-OXA-48was transformed into E.coli BL21(DE3),and the recombinant strain pET32a(+)-OXA-48-BL21(DE3)was identified by colony PCR and sequencing. Taking A_(600)(0. 3,0. 5 and 0. 7),IPTG final concentration(0. 4,0. 6 and 0. 8mmol/L)and induction time(2,4 and 6 h)as variables and mRNA transcription level as response value,an orthogonal experiment with three factors and three levels was designed to optimize the induced expression conditions of the plasmid. The drug resistance of recombinant strain pET32a(+)-OXA-48-BL21(DE3)to Imipenem(IPM),Meropenem(MEM),Ceftriaxone(CRO)and Cefepime(FEP)was detected by disk diffusion method;The adaptability was detected by biofilm formation test and serum resistance test. Mouse alveolar macrophages(MH-S)were infected with pET32a(+)-OXA-48-BL21(DE3),pET32a(+)-BL21(DE3)and E.coli BL21(DE3)strains,respectively. The mRNA transcription levels of TLR2,TLR4 and NF-кB(p65)genes were detected by qRT-PCR method,and the expressions of Interleukin-6(IL-6),IL-10,tumor necrosis factor-α(TNF-α)and transforming growth factor-β(TGF-β)were detected by ELISA. Results The recombinant strain pET32a(+)-OXA-48-BL21(DE3)was constructed correctly as identified by colony PCR and sequencing. The optimum induction conditions were as follows:A_(600)of 0. 3,IPTG final concentration of 0. 6 mmol/L and induction time of 2 h. Compared with pET32a(+)-BL21(DE3)strain,the resistance of recombinant strain pET32a(+)-OXA-48-BL21(DE3)to IPM,MEM,CRO and FEP significantly decreased(t = 7. 14～22. 32,P < 0. 05),the biofilm formed significantly increased(t = 15. 69,P < 0. 05),and the survival rate in serum significantly increased(t = 10. 60,P < 0. 05);The mRNA transcription level of TLR2 gene in MH-S cells infected with pET32a(+)-OXA-48-BL21(DE3)significantly increased 24 h after infection(t = 5. 77,P < 0. 05),while the mRNA transcription level of TLR4 and NF-кB(p65)genes(t = 3. 71～10. 06,P < 0. 05)and the expression level of IL-6 significantly increased 12 and 24 h after infection. Compared with the normal group,the expression of IL-6and TNF-α in MH-S cells infected with pET32a(+)-OXA-48-BL21(DE3)increased significantly at 6,12 and 24 h after infection(t = 7. 90 ～ 13. 44 and 5. 40～6. 32 respectively,each P < 0. 01),while the expression of IL-10 decreased significantly(t = 3. 15～4. 08,each P < 0. 05). There was no significant difference in the expression of TGF-β(t = 0. 013～1. 41,each P > 0. 05). The expression of IL-6 was significantly higher than that in pET32a(+)-BL21(DE3)group at 12 and 24 h after infection(t = 2. 92 and 3. 79 respectively,each P < 0.05) Conclusion Overexpression of OXA-48 can reduce bacterial drug resistance,improve bacterial adaptability and the transcription level of factors related to TLR signaling pathway in host cells,and affect the expression level of downstream cytokines in host cells.

Activation of insulin-like growth factor-1 receptor (IGF-1R) promotes growth of colorectal cancer through triggering the MEX3A-mediated degradation of RIG-I

Insulin-like growth factor-1 receptor (IGF-1R) has been made an attractive anticancer target due to its overexpression in cancers. However, targeting it has often produced the disappointing results as the role played by cross talk with numerous downstream signalings. Here, we report a disobliging IGF-1R signaling which promotes growth of cancer through triggering the E3 ubiquitin ligase MEX3A-mediated degradation of RIG-I. The active β-arrestin-2 scaffolds this disobliging signaling to talk with MEX3A. In response to ligands, IGF-1Rβ activated the basal βarr2 into its active state by phosphorylating the interdomain domain on Tyr64 and Tyr250, opening the middle loop (Leu130‒Cys141) to the RING domain of MEX3A through the conformational changes of βarr2. The models of βarr2/IGF-1Rβ and βarr2/MEX3A could interpret the mechanism of the activated-IGF-1R in triggering degradation of RIG-I. The assay of the mutants βarr2Y64A and βarr2Y250A further confirmed the role of these two Tyr residues of the interlobe in mediating the talk between IGF-1Rβ and the RING domain of MEX3A. The truncated-βarr2 and the peptide ATQAIRIF, which mimicked the RING domain of MEX3A could prevent the formation of βarr2/IGF-1Rβ and βarr2/MEX3A complexes, thus blocking the IGF-1R-triggered RIG-I degradation. Degradation of RIG-I resulted in the suppression of the IFN-I-associated immune cells in the TME due to the blockade of the RIG-I-MAVS-IFN-I pathway. Poly(I:C) could reverse anti-PD-L1 insensitivity by recovery of RIG-I. In summary, we revealed a disobliging IGF-1R signaling by which IGF-1Rβ promoted cancer growth through triggering the MEX3A-mediated degradation of RIG-I.

Caracterización fenotípica y molecular de cepas de Klebsiella pneumoniae productores de carbapenemasas tipo OXA-48 circulantes en Chile / Phenotypic and molecular characterization of OXA-48 like producing Klebsiella pneumoniae isolates in Chile

INTRODUCCIÓN: La aparición y diseminación de Enterobacterales resistentes a carbapenémicos ha generado un gran impacto en las infecciones asociadas a la atención de salud en el mundo. Recientemente, en Chile se detectó un brote por Klebsiella pneumoniae productora de carbapenemasas tipo oxacilinasas (OXA) de la subfamilia tipo OXA-48, reportándose los primeros casos en pacientes hospitalizados mayoritariamente en la zona norte del país. OBJETIVO: Determinar los perfiles fenotípicos, genotípicos y de susceptibilidad antimicrobiana de 16 cepas referidas durante mayo del año 2021 desde las regiones de Antofagasta y Metropolitana al Laboratorio de Referencia del Instituto de Salud Pública. METODOLOGÍA: Las cepas provenientes de muestras clínicas fueron analizadas mediante técnicas tradicionales (Kirby-Bauer y epsilometría) y automatizadas, además de técnicas colorimétricas, inmunocromatográficas y moleculares (RPC y PFGE). Resultados: Se detectó la presencia de los genes blaoxa-48 y blaoxa-232 con una resistencia inusual, tanto a carbapenémicos (ertapenem, imipenem y meropenem) como a cefalosporinas (cefepime, cefotaxima y ceftazidima), además de piperacilina/tazobactam y temocilina. Se detectaron dos subtipos por PFGE, siendo predominante el clon CL-Kpn-Spe-329 (93,8%) con dos mecanismos de resistencia identificados: carbapenemasa y β-lactamasa de espectro extendido (BLEE). CONCLUSIÓN: Ante esta alerta epidemiológica es necesario unificar criterios existentes en la red asistencial nacional para la oportuna detección, vigilancia y control de posibles brotes de cepas productores de oxacilinasa tipo OXA-48.

BACKGROUND: The appearance and spread of carbapenems-resistant Enterobacterales have generated a major impact on health care-associated infections worldwide. Recently, a Klebsiella pneumoniae outbreak expressing OXA-48 like-carbapenemases was detected in Chile, the first reported cases corresponded to hospitalized patients mainly from northern Chile. AIM: To characterize the phenotypic and genotypic profiles of antimicrobial susceptibility of 16 clinical isolates referred during May 2021 from Antofagasta and Metropolitan regions to the Reference Laboratory of Instituto de Salud Publica. METHODS: Antimicrobial susceptibility of all strains was analyzed using traditional (Kirby-Bauer and epsilometry) and automated methods, and complemented with colorimetric, immunochromatographic and molecular (PCR and PFGE) techniques. RESULTS: As a result of the genetic characterization, blaoxa-48 and blaoxa-232 genes were detected, showing the isolates an unusual resistance profile to both carbapenems (ertapenem, imipenem, and meropenem) and cephalosporins (cefepime, cefotaxime, and ceftazidine), as well as piperacillin/ tazobactam and temocillin. Two subtypes were detected by PFGE, with a predominant clone CL-Kpn-Spe-329 (93.8%), with two resistance mechanisms identified: carbapenemase and extended-spectrum β-lactamase (ESBL). CONCLUSION: Due to this epidemiological alert, it is essential the establishment of national guidelines for early detection, surveillance, and control of future outbreaks of OXA-48 like carbapenemases isolates.

Descripción de una cepa de Klebsiella pneumoniae con gen blaOXA-48 en Lima-Perú / Description of a Klebsiella pneumoniae strain with blaOXA-48 gene in Lima-Peru

Señor editor: La propagación de enterobacterales productoras de carbapenemasas se ha convertido en una importante amenaza para la salud mundial. El gen blaOXA-48 produce una carbapenemasa de clase "D" (según la clasificación de Ambler) que expresa un fenotipo resistente a penicilinas, penicilinas con inhibidores de beta-lactamasas, cefalosporinas de primera generación y sensibilidad reducida a los carbapenemes, sensibilidad reducida o casi nula a las cefalosporinas de amplio espectro.

Dear Editor: The spread of carbapenemase-producing Enterobacteriaceae has become a major threat to global health. The blaOXA- gene blaOXA-48 produces a class "D" carbapenemase (according to Ambler's classification) that expresses a phenotype resistant to penicillins, penicillins with beta-lactamase inhibitors, first-generation cephalosporins and reduced sensitivity to carbapenems, reduced or near-zero sensitivity to broad-spectrum cephalosporins.48 produces a class "D" carbapenemase (according to Ambler's classification) that expresses a phenotype resistant to penicillins, penicillins with beta-lactamase inhibitors, first-generation cephalosporins and reduced sensitivity to carbapenems, reduced or near-zero sensitivity to broad-spectrum cephalosporins.

Susceptibility testing for aztreonam plus ceftazidime/avibactam combination: A general guidance for clinical microbiology laboratories in India

Metallo beta-lactamases-producing Gram-negative infection is often challenging and there is no defined treatment option. In recent years, the combination of aztreonam with ceftazidime-avibactam has gained much clinical attention mainly for MBL-producing Enterobacterales, while MBL-producing P. aeruginosa and A. baumannii are likely to be resistant. A consensus susceptibility testing method for this triple combination has yet to be recommended. Various methods such as broth disk elution, disk stacking, gradient strip stacking, and strip crossing have been proposed for testing this combination. Among them, broth disk elution and strip based testing methods showed good correlation with the broth micro-dilution method.

Primer reporte de Enterobacterales dobles productores de carbapenemasas en hospitales de Paraguay. Año 2021

RESUMEN Las carbapenemasas se encuentran ampliamente distribuidas en nuestro país, tanto en bacilos gramnegativos fermentadores como no fermentadores. Durante 2021, se ha reportado incremento de cepas con estas enzimas. Con el objetivo de evaluar la doble producción de carbapenemasas en Enterobacterales y comunicar su circulación, fue puesta a punto una PCR convencional múltiple. Estudio retrospectivo en 128 aislamientos provenientes de 20 centros colaboradores de la Red Nacional de Vigilancia de la RAM (Capital, Central e interior del país), remitidos al LCSP entre febrero y setiembre de 2021, para confirmación y genotipificación de carbapenemasas. Se realizaron pruebas fenotípicas y colorimétricas con sustratos específicos, y pruebas genotípicas (PCR convencional múltiple) para la detección simultánea de varios genes de resistencia (bla NDM, bla KPC, bla OXA-48-like, bla IMP y bla VIM). De los 128 aislamientos estudiados, 107 correspondieron a Klebsiella pneumoniae, 14 a Enterobacter cloacae complex, entre otros; aislados en mayor frecuencia de muestras de orina (30%), respiratorias (30%), sangre y catéter (24%). Los genes de resistencia a los carbapenemes detectados fueron: bla NDM (77,3%), bla KPC (17,2%); siendo confirmada la doble producción de carbapenemasas en 7 aislamientos (5,5%) provenientes de 4 centros diferentes de la capital de país y uno de Central; 6 de ellas (K. pneumoniae) con bla NDM+bla KPC y 1 (E. cloacae complex) con bla NDM+bla OXA-48-like; confirmando circulación de Enterobacterales dobles productores de carbapenemasas en el país (KPC+NDM y OXA+NDM); hallazgos que obligan a proveer de capacidades de detección, de manera a que se puedan tomar medidas oportunas y eficaces de contención y control.

ABSTRACT Carbapenemases are widely distributed in our country, both in fermenting and non-fermenting gram-negative bacilli. During 2021, an increase in strains with these enzymes has been reported. In order to evaluate the double production of carbapenemases in Enterobacterales and communicate their circulation, a multiple conventional PCR was set up. Retrospective study carried out in 128 isolates from 20 collaborating centers of the National AMR Surveillance Network (Capital, Central and interior of the country), sent to the LCSP between February and September 2021, for confirmation and genotyping of carbapenemases. Phenotypic and colorimetric tests were performed with specific substrates, as well as genotypic tests (multiple conventional PCR) for the simultaneous detection of several resistance genes (blaNDM, blaKPC, blaOXA-48-like, blaIMP and blaVIM). Of the 128 isolates studied, 107 corresponded to Klebsiella pneumoniae, 14 to Enterobacter cloacae complex, among others; isolated in higher frequency from urine (30%), respiratory (30%), blood and catheter (24%) samples. The genes for resistance to carbapenems detected were: blaNDM (77.3%), blaKPC (17.2%); the double production of carbapenemases was confirmed in 7 isolates (5.5%) from 4 different centers in the capital of the country and one in Central; 6 of them (K. pneumoniae) with blaNDM + blaKPC and 1 (E. cloacae complex) with blaNDM + blaOXA-48-like; confirming circulation of double Enterobacterales producers of carbapenemases in the country (KPC + NDM and OXA + NDM); findings that require the provision of detection capabilities, so that timely and effective containment and control measures can be taken.

First Clinical Cases of OXA-48-Producing Klebsiella pneumoniae in Peru / Primeros casos clínicos de infecciones por Klebsiella pneumoniae productora de OXA-48 en Perú

Background: Carbapenemase-producing Enterobacteriaceae(CPE) represents a global public health concern and systemic infectionsassociatedwithOXA-48 carbapenemase are increasingly being reported in Latin America. Here, we present the first 2 cases of systemic infections by OXA-48-ProducingKlebsiellapneumoniaein Peru. A favorable clinical response was observed after targeted treatment with colistin as a backbone.

Introducción: Las enterobacterias productoras de carbapenemasas (EPC) representan un problema de salud pública y cada vez hay más reportes de infecciones sistémicas asociadas con la carbapenemasa OXA-48 en America Latina. Presentamos los primeros 2 casos de infecciones sistémicas por Klebsiella pneumoniae productora de OXA-48 en Perú. Se observó una respuesta clínica favorable luego del tratamiento dirigido con colistina como base.

Prevalence of carbapenemase production in Pseudomonas aeruginosa isolates causing clinical infections in Lagos University Teaching Hospital, Nigeria

Background: Pseudomonas aeruginosa has been highly associated with carbapenem resistance in which carbapenemases has been suggested to be a major contributory factor. Hence the objective of this study was to phenotypically detect KPC-type carbapenemase, metallo-ß-lactamase and OXA-48 carbapenemase production in clinical isolates of P. aeruginosa in Lagos University Teaching Hospital (LUTH), Nigeria Methodology: One hundred and seventy-one P. aeruginosa isolates consecutively recovered from clinical specimens of patients with infections at the Medical Microbiology and Parasitology laboratory of the hospital were identified using MicrobactTM 24E kit. Preliminary screening for carbapenem resistance was determined by the disc diffusion method on Mueller-Hinton agar using single discs of meropenem and imipenem. Phenotypic detection of carbapenemase production among carbapenem-resistant isolates was performed by the combination disc test of meropenem-phenylboronic acid (MRPBO) and meropenem-dipicolinic acid (MRPDP) as recommended by EUCAST 2013 guideline. Results: Out of the 171 P. aeruginosa isolates, 35 (20.5%) were carbapenem non-susceptible (resistant) while carbapenemase production was detected in 27 (77.1%) of these carbapenem resistant isolates, and no enzyme was detected in 8 (22.9%). Of the 27 carbapenemase producing isolates, 22 (81.5%) produced MBL, 1 (3.7%) produced KPC, while 4 (14.8%) produced both KPC and MBL enzymes. Conclusion: This study revealed that carbapenem resistance among P. aeruginosa clinical isolates in our institution is gradually increasing. The mechanism for this rise is associated with carbapenemases, with MBL being the major carbapenemase involved. There is the need to ensure strict compliance with the LUTH infection control guidelines in order to check the rising incidence of infection caused by carbapenem resistant P. aeruginosa

Malformación genital: disparador del diagnóstico de variantes severas de síndrome de Klinefelter / Genital malformation: trigger of the diagnosis of severe variants of Klinefelter syndrome

Resumen: Introducción: El síndrome de Klinefelter y sus variantes, como alteración en el número de cromosomas sexuales, se encuentra entre los trastornos del desarrollo sexual. Sus portadores manifiestan hipogonadismo hipergonadotrófico en la pubertad; las variantes severas presentan además problemas neurocognitivos y del lenguaje desde edades tempranas. Objetivo: Describir dos pacientes portadores de mal formación genital con diagnóstico genético de variantes severas de síndrome de Klinefelter; y revisar aspectos clínicos y terapéuticos. Casos Clínicos: Caso 1: Diagnóstico de genitales atípicos al nacer: Falo pequeño y corvo con meato uretral a nivel escrotal y escroto bífido. Sin otra anomalía somática, excepto sutil clinodactilia del 5 dedo. Cariotipo: 49,XXXXY. Al año de vida se reconstruyeron los genitales. Evolucionó con retraso global del desarrollo, principalmente del lenguaje, manejado con estimulación temprana kinésica y fonoaudiológica desde los 2 meses, logró integrarse en un jardín de infantes. Caso 2: Al mes de vida se constató falo pequeño y corvo severo (más de 70°), testículos en bolsa. Cariotipo: 48,XXYY. Al año de vida se corrigió malformación del pene. Evolucionó con retraso global del desarrollo, fundamentalmente en el lenguaje expresivo, y fue manejado con el equipo de estimulación temprana desde los 4 meses, logrando adaptación en un jardín de infantes. Conclusión: Las malformaciones genitales condujeron al diagnóstico de variantes severas de síndrome de Klin efelter, y fueron corregidas alrededor del año de vida. La identificación temprana de estas variantes permitió la intervención del equipo de neuroestimulación, favoreciendo el desarrollo neurocognitivo y la integración social de estos niños.

Abstract: Introduction: Among the disorders of sexual development, Klinefelter syndrome and its variants are classified as an alteration in the number of sex chromosomes. These patients show signs of hypergonadotropic hypogonadism at puberty, however cases of severe variants also present neurocognitive and language problems from an early age. Objective: To describe two patients with genital malformation with genetic diagnosis of severe variants of Klinefelter syndrome, and to review clinical and therapeutic aspects. Clinical Cases: Case 1: Diagnosis of atypical genitalia at birth: Small and curved phallus with the urethral meatus at scrotal level, and bifid scrotum. No other somatic abnormality was observed, except for subtle clinodactyly of the fifth finger. Karyotype: 49, XXXXY. At one year of life, genitalia were reconstructed. The patient presented a global developmental delay, mainly in language, which was managed with early stimulation and speech and language therapy since he was two months old. Finally, he was able to attend kindergarten. Case 2: At one month of life, a small and severe curved phallus (more than 70°) was observed, and testicles were in the scrotum. Karyotype: 48, XXYY. At one year of life, the penile malformation was corrected. The patient presented global developmental delay, mainly in expressive language which was managed with early stimulation since the age of four months, achieving kindergarten attendance. Conclusion: Genital malformations led to the diagno sis of severe variants of Klinefelter syndrome, and were corrected around the year of life. The early identification of these variants allowed the intervention of the neurostimulation team, favoring the neurocognitive development and social integration of these children.

Chemical constituents of Picrasma quassioides / 中草药

Objective: To study the chemical constituents of Picrasma quassioidies. Methods: The isolation and purification were carried out by column chromatography on silica gel, ODS, Sephadex LH-20 and semi-preparative RP-HPLC. The structures were elucidated on the basis of physicochemical properties and spectroscopic analysis. Results: A total of 12 alkaloids and four quassinoids were isolated and identified from 80% ethanol aqueous extract of the stems of P. quassioides. They were named as 1-hydroxymethyl-4-methoxy-β-carboline (1), 1-methoxicabony-β-carboline (2), 1-methoxicabony-4-methoxy-β-carboline (3), 1-methoxicabony-4,8-dimethoxy-β-carboline (4), 1-ethyl-4-methoxy-β-carboline (5), 1-ethyl-4,8-dimethoxy-β-carboline (6), picrasidine I (7), canthin-6-one (8), 5-methoxyl-canthin-6-one (9), 4-methoxyl-5-hydroxyl-canthin-6-one (10), 4,5-dimethoxyl- canthin-6-one (11), quassidine B (12), quassin (13), nigakilactone B (14), nigakilactone E (15) and norquassin (16). Conclusion: Compound 1 is a new β-carboline alkaloid, named as kumujantine D, and compound 4 is isolated from P. quassioidies for the first time.

Applicability of the 48/6 Model of Care as a Health Screening Tool, and its Association with Mobility in Community-Dwelling Older Adults

BACKGROUND: The 48/6 Model of Care is an integrative care initiative for improving the health outcomes of hospitalized older patients; however, its applicability in community-dwelling older adults as a health screening tool has not been investigated. The present study aimed to examine the applicability of this model, prevalence of dysfunction in 6 care areas, and its relationship with self-reported mobility in community-dwelling older adults.METHODS: This was a cross-sectional survey study of community-dwelling adults aged 65 or older. Participants were screened for problems using 9 items corresponding to the 6 care areas of the 48/6 Model of Care (cognitive functioning, functional mobility, pain management, nutrition and hydration, bladder and bowel management, and medication management). Mobility was assessed via the Life-Space Assessment (LSA). We examined the correlation between each screening item and the LSA.RESULTS: A total of 444 older adults (260 women, 58.6%) participated. The mean number of health problems was 2.3 ± 2.1, with the most common being pain, cognitive impairment, and urinary incontinence. These problems and LSA scores were significantly different by age groups. A multiple regression analysis showed that polypharmacy (β = −10.567, P < 0.001), dysphagia (β = −9.610, P = 0.021), and pain (β = −7.369, P = 0.004) were significantly associated with life-space mobility after controlling for age.CONCLUSION: The 48/6 Model of Care is applicable to community-dwelling older adults, who show high prevalence of dysfunction in the 6 care areas. This study supports the role of the model in screening for the health status of older adults living in the community, and in estimating mobility.

Rapid Identification of OXA-48-like, KPC, NDM, and VIM Carbapenemase-Producing Enterobacteriaceae From Culture: Evaluation of the RESIST-4 O.K.N.V. Multiplex Lateral Flow Assay

There is an urgent need for accurate and rapid diagnostic assays capable of identifying carbapenemase-producing Enterobacteriaceae (CPE). We assessed the performance of the RESIST-4 O.K.N.V. (OKNV) assay (Coris BioConcept, Gembloux, Belgium) for the identification of oxacillinase (OXA)-48-like-, Klebsiella pneumoniae carbapenemase (KPC)-, New Delhi metallo-β-lactamase (NDM)-, and Verona integron-encoded metallo-β-lactamase (VIM)-producing Enterobacteriaceae grown on sheep blood agar (SBA) and the CHROMagar KPC medium. Sixty-five carbapenem-resistant Enterobacteriaceae (CRE) isolates with characterized carbapenemase content were used to evaluate the OKNV assay. The assay correctly identified all 30 isolates that produced one of the four targeted carbapenemase families. Additionally, it correctly identified 15 isolates that co-produced KPC and NDM, VIM and NDM or OXA-48-like and NDM, but failed to identify an NDM-1 and OXA-232 co-producing Klebsiella pneumoniae isolate. All 16 non-carbapenemase-producing CRE and four CPE isolates exhibited negative results, and no cross-reaction was observed. Overall, the sensitivity and specificity of the assay were 97.8% and 100%, respectively. The OKNV assay is an accurate and rapid assay for identifying OXA-48-like, KPC, NDM, and VIM carbapenemases produced by Enterobacteriaceae isolates cultured on both SBA and the CHROMagar KPC media in the clinical microbiology laboratory.

Will ceftazidime/avibactam plus aztreonam be effective for NDM and OXA-48-Like producing organisms: Lessons learnt from In vitro study

Introduction: Carbapenem resistance (CR) in Klebsiella pneumoniae is mainly mediated by bla NDM and bla OXA-48 carbapenemases. Newer Food and Drug Administration-approved antimicrobial ceftazidime/avibactam (C/A) has a potent activity against bla OXA-48-like producers. However, its activity is limited in organisms co-producing bla NDM and bla OXA-48-like. Addition of aztreonam (ATM) to C/A potentially expands the spectrum of coverage for carbapenemase co-producers. With this, we aimed to determine the synergistic activity of combination of C/A plus ATM against bla NDM, bla OXA-48-like and co-producers of bla NDM + bla OXA-48-like producing CR Klebsiella pneumoniae (CRKp). Materials and Methods: A total of 12 isolates of CRKp-harbouring genes encoding bla NDM and bla OXA-48-like were tested. Minimum inhibitory concentrations (MICs) were determined for several antimicrobial agents, including C/A (0.5�?g/ml) by broth microdilution method. Checkerboard assay was performed for the combination of C/A plus ATM at varying concentrations. Fold differences in the MIC of C/A with and without addition of ATM were determined to infer synergistic effects. Results: MIC of C/A and ATM ranged from 0.5 to >8 ?g/ml and 64 to 2048 ?g/ml, respectively. Two isolates were susceptible to C/A with MIC of 0.5 and 1 ?g/ml, while others were resistant with MIC of >8 ?g/ml. Synergistic effects of >8-fold MIC difference in C/A MIC were noted with addition of ATM at 4 ?g/ml. This was observed for all CRKp with profiles of bla NDM, bla OXA-48-like and co-producers of bla NDM + bla OXA-48-like genes, which was a promising effect. Notably, all five of the colistin-resistant CRKp were inhibited with >8-fold MIC difference in the combination of C/A plus ATM at 4 ?g/ml. Conclusion: With the increasing burden of CRKp, the use of C/A with ATM combination seems to be very promising, especially for bla NDM, bla OXA-48-like and co-producers of bla NDM + bla OXA-48like carbapenemases.

Colistin-sparing approaches with newer antimicrobials to treat carbapenem-resistant organisms: Current evidence and future prospects

Antimicrobial resistance is on the rise across the globe. Increasing incidence of infections due to carbapenem resistance organisms is becoming difficult to treat, due to the limited availability of therapeutic agents. Very few agents such as colistin, fosfomycin, tigecycline and minocycline are widely used, despite its toxicity. However, with the availability of novel antimicrobials, beta-lactam/beta-lactamase inhibitor-based and non-beta-lactam-based agents could be of great relief. This review covers three important aspects which include (i) current management of carbapenem-resistant infections, (ii) determination of specific types of carbapenemases produced by multidrug-resistant and extensively drug-resistant Gram-negative pathogens and (iii) the currently available novel beta-lactam/beta-lactamase inhibitors and non-beta-lactam-based agents' laboratory findings, clinical outcome and implications.

Effect of incRNA uc. 48 + on liver glycogen in type 2 diabetic rats / 中国药理学通报

Aim: To observe the effect of uc.48 + small interference RNA (siRNA) on liver glycogen abnormality in type 2 diabetic rats and its possible mechanism. Methods: The diabetes model was established by feeding high glucose and high fat diet combined with streptozotocin(STZ). After the success of the model, the long noncoding RNA uc. 48 + siRNA was injected into the rat body via tail vein. The changes of blood glucose and the content of liver glycogen were detected dynamically, and the liver glycogen was detected one week after injection. Glucokinase (GK) mRNA and protein expression in liver tissues of each group were detected by qPCR and Western blot. Results: It was observed that postprandial blood glucose and fasting blood glucose decreased in diabetic model rats after treated with uc. 48 + siRNA compared with those in model rats. The level of liver glycogen in diabetic model rats was significantly lower than that in control group. The synthesis of liver glycogen in diabetic model rats with uc. 48 + siRNA treatment increased compared with that in diabetic model group. The expressions of GK mRNA and protein in the diabetic model group were significantly lower than those in control group. The expression of GK mRNA and protein markedly increased after uc. 48 + siRNA treatment. Conclusions: uc. 48 + siRNA reduces blood glucose and increases glycogen synthesis in type 2 diabetic rats, and its mechanism may involve in increasing GK expression and Aktl phosphorylation.

Effect of Shouwu Jiangzhi decoction on hyperlipidemia Golden Syrian hamsters based on TNF-α/MAPK/apoB-48 pat / 中国药科大学学报

@#To investigate the mechanism of Shouwu Jiangzhi decoction in treatment of hyperlipidemia by suppress apoB-48 in small intestines, Golden Syrian hamsters were randomly devided into blank group, model group, fenobrate treatment group and Shouwu Jiangzhi decoction treatment group based on weight. The hyperlipidemia models of golden Syrian hamsters were induced by high fat diet(HFD)treatment for 4 weeks, then administered orally with drugs for 4 weeks. The serum indexes of HDL-C, LDL-C, TG and TC were determined by microplate methods, ELISA kits were used to evaluate the contents of serum TNF-α, apoB-48 and FFA. The protein expression levels of p38, ERK, JNK, SREBP, TNF-α and apoB-48 in small intestines were determined by Western blots. The results showed that Shouwu Jiangzhi decoction can effectively increase the serum HDL-C level and reduce the serum level of TG, LDL-C, TNF-α and apoB-48 in HFD-induced hamsters. Furthermore, Shouwu Jiangzhi decoction can significantly downregulate the protein expressions of p38, JNK, ERK, SREBP, TNF-α and apoB-48 in small intestines. Results above indicate that Shouwu Jiangzhi decoction may downregulate the protein expression of apoB-48 to treat hyperlipidemia via partially downregulating TNF-α/MAPK signal pathway.

Molecular detection of Enterobacteriaceae isolates producing blaOXA-48 and blaOXA-181 genes: A single centre study

@#Introduction: OXA-48, a carbapenem-hydrolysing class D β-lactamase, and its variant, OXA-181, are increasingly reported worldwide. This study aimed to describe the prevalence and distribution of OXA-48 and OXA-181 carbapenem-resistant Enterobacteriaceae (CRE) in a tertiary medical centre in Malaysia. Materials & Methods: A total of 13,098 Enterobacteriaceae isolates from various clinical samples were sent to our laboratory between January 2011 and December 2012. Of these, 90 demonstrated reduced susceptibility to at least one carbapenem and were included in this study. Only 88 isolates were successfully subcultured on blood agar (BA). Another 2 isolates failed to grow and were excluded. Of the 88, 2 isolates had the same identification number (repetitive isolates); therefore, 1 isolate was excluded from further analyses. Only 87 isolates were subjected to molecular detection of the blaOXA-48 and blaOXA-181 genes by polymerase chain reaction. Results: Eighty-seven non-repetitive isolates grew following subculture on BA. Of these, 9 (10.34%) were positive for OXA-48 (7 Klebsiella pneumoniae, 2 Escherichia coli). Each isolate originated from different patients. All patients had a history of treatment with at least one cephalosporin and/or carbapenem prior to the isolation of OXA-48 CRE. OXA-181 was detected in one (1.15%) out of the 87 isolates; Conclusions: The prevalence of OXA-48 and OXA-181 CRE among all Enterobacteriaceae isolates in our institution is 0.069% and 0.008%, respectively. Nevertheless, our findings suggest that OXA48 and OXA-181 carbapenemases appear to be important and possibly under-recognised causes of carbapenem resistance in Malaysia.

Performance of "RESIST-3 O.K.N. K-SeT" immunochromatographic assay for the detection of OXA-48 like, KPC, and NDM carbapenemases in Klebsiella pneumoniae in Turkey

ABSTRACT In this study, the performance of the "RESIST-3 O.K.N. K-SeT" (Coris BioConcept, Gembloux, Belgium) immunochromatographic assay was evaluated in 132 Klebsiella pneumoniae comprising 102 carbapenem resistant and 30 carbapenem susceptible isolates. Genotypically known isolates of Gram negative bacteria (n = 22) including various species were also tested by the assay as controls. The isolates tested by the immunochromatographic assay and also were run PCR for bla KPC, bla IMP, bla VIM, bla NDM, and bla OXA-48. The rates of bla NDM, bla OXA-48, and bla KPC in carbapenem resistant isolates were found at 52.9%, 39.2%, and 2.0%, respectively. Both bla NDM and bla OXA-48 were found in six (5.9%) isolates. The results of the assay showed 100% concordance with those obtained by PCR in 132 K. pneumoniae. The agreement between the two methods was found to be identical at the isolate level. The assay also correctly detected all genotypically known isolates of Escherichia coli, Serratia marcescens, Citrobacter freundii, Enterobacter cloacae, K. pneumoniae carrying bla KPC, bla NDM, and/or bla OXA-48. On the other hand, the assay did not exhibit any cross-reaction in control isolates harboring bla IMP and bla VIM. We conclude that the RESIST-3 O.K.N. K-SeT is a reliable, rapid, and user friendly test and we recommend it for routine diagnostic laboratories.

Rapid detection of the commonly encountered carbapenemases (New Delhi metallo-?-lactamase, OXA-48/181) directly from various clinical samples using multiplex real-time polymerase chain reaction assay

Background: Resistance due to New Delhi metallo-?-lactamase (NDM) and OXA-48/181 continues to emerge as a threat which is associated with nosocomial outbreaks and is a serious healthcare concern. Phenotypic detection being laborious and time-consuming requires rapid detection of NDM and OXA-48/181, which is achieved through real-time polymerase chain reaction (RT-PCR). Materials and Methods: In this study, RT-PCR assay was developed to simultaneously detect NDM and OXA-48/181. The assay was validated on 102 non-duplicate, phenotypically characterised clinical samples. Results: The assay showed a sensitivity and specificity of 97% and 100% for the detection of carbapenemases in comparison to conventional PCR. The in-house developed multiplex RT-PCR would help to rule-in the presence of NDM and OXA-48/181. Conclusions: Rapid detection of these carbapenemases would be assist in better patient management, in terms of accurate antimicrobial treatment, help in cohorting infected from uninfected patient to prevent spread.

Rol del enterocito en la dislipidemia de la diabetes mellitus tipo 2 / Role of the enterocyte in type 2 diabetes mellitus associated dyslipidemia

En la diabetes mellitus tipo 2 el aumento en la producción de quilomicrón en el estado post-prandial se asocia a mayor riesgo cardiovascular. La evidencia actual posiciona al enterocito como actor principal en la dislipemia de la diabetes mellitus tipo 2 debido a que aumenta la producción de apolipoproteína B-48 en respuesta a una elevación de ácidos grasos libres y glucosa. El metabolismo del quilomicrón se encuentra regulado por múltiples factores independientes además de la ingesta de grasa alimentaria. Entre estos factores se destacan las hormonas intestinales, como el péptido similar al glucagón tipo 1 que disminuye la producción de apolipoproteína B-48 y el péptido similar al glucagón tipo 2 que la aumenta. Por otro lado, la insulina inhibe de forma aguda la producción de quilomicrón en el sujeto sano mientras que en la diabetes mellitus tipo 2, este efecto está ausente. La comprensión de los factores reguladores emergentes de la secreción de quilomicrón permite vislumbrar nuevos mecanismos de control en su metabolismo y aportar estrategias terapéuticas focalizadas en la hiperlipidemia posprandial en la diabetes mellitus tipo 2 con la reducción del riesgo cardiovascular.

In type 2 diabetes mellitus there is an overproduction of chylomicron in the postprandial state that is associated with increased cardiovascular risk. Current evidence points out a leading role of enterocyte in dyslipidemia of type 2 diabetes mellitus, since it increases the production of apolipoprotein B-48 in response to a raise in plasma free fatty acids and glucose. The chylomicron metabolism is regulated by many factors apart from ingested fat, including hormonal and metabolic elements. More recently, studies about the role of gut hormones, have demonstrated that glucagon-like peptide-1 decreases the production of apolipoprotein B-48 and glucagon-like peptide-2 enhances it. Insulin acutely inhibits intestinal chylomicron production in healthy humans, whereas this acute inhibitory effect on apolipoprotein B-48 production is blunted in type 2 diabetes mellitus. Understanding these emerging regulators of intestinal chylomicron secretion may offer new mechanisms of control for its metabolism and provide novel therapeutic strategies focalized in type 2 diabetes mellitus postprandial hyperlipidemia with the reduction of cardiovascular disease risk.