Resistencia a colistina en aislados de Klebsiella pneumoniae resistente a carbapenémicos en un hospital pediátrico de Corrientes / Colistin resistance in carbapenem-resistant Klebsiella pneumoniae isolates from a pediatric hospital from Corrientes, Argentina

INTRODUCCIÓN: Existe un incremento de las infecciones por Klebsiella pneumoniae resistente a carbapenémicos (KPRC) en la población pediátrica y los datos epidemiológicos son limitados. OBJETIVOS: Conocer la frecuencia de KPRC en pacientes pediátricos, determinar la actividad in vitro de colistina y detectar el gen mcr-1 en dichos aislados. MATERIALES Y MÉTODOS: Se estudiaron 220 aislados de K. pneumoniae en un hospital pediátrico durante los años 2018 y 2019. La susceptibilidad antimicrobiana se determinó por microdilución en caldo según CLSI y EUCAST. Los genes blaKPC, blaNDM, blaIMP, blaVIM, blaOXA-48 y mcr-1 se analizaron mediante reacción de polimerasa en cadena (RPC). RESULTADOS: El 9,5% (n: 21) de los aislados fueron caracterizados como KPRC, donde se observó una resistencia a colistina de 47,6% (10/21) con valores de CIM50 de 2 μg/mL y CIM90 de > 4 μg/mL. En todos los aislados de KPRC se caracterizó el gen blaKPC y no se detectó el gen mcr-1. El perfil de resistencia observado en otros antimicrobianos fue el siguiente: gentamicina 100% (n: 21), ciprofloxacina 100% (n: 21), cotrimoxazol 100% (n: 21) y amikacina 19% (n: 4). Se observó 100% de sensibilidad a tigeciclina y ceftazidima/avibactam. CONCLUSIÓN: Este estudio demuestra un valor significativo de la resistencia a colistina en comparación a ceftazidima/avibactam y tigeciclina.

BACKGROUND: There is an increase of carbapenem-resistant Klebsiella pneumoniae (CRKP) infections in the pediatric population and epidemiological data are limited. Aim: To calculate the frequency of CRKP in pediatric patients, to determine the in vitro activity of colistin and to detect the presence of mcr-1 gene in said isolates. METHODS: 220 isolates of K. pneumoniae were studied in a pediatric hospital between January 2018 and December 2019. Antimicrobial susceptibility was determined by microdilution in broth according to guidelines of CLSI and EUCAST. The genes blaKPC, blaNDM, blaIMP, blaVIM, blaOXA-48 and mcr-1 were detected by polymerase chain reaction (PCR). RESULTS: 9.5% (n: 21) of the isolates were characterized as CRKP, where was observed a resistance to colistin of 47.6% (10/21) with values of MIC50 of 2 μg/mL and MIC90 of ≥ 4 μg/mL. In 100% of CRKP strains the blaKPC gene was detected and the mcr-1 gene was not found. The resistance profile to other antimicrobials was as follow: gentamicin 100% (n: 21), trimethoprim/sulfamethoxazole 100% (n: 21), ciprofloxacin 100% (n: 21), amikacin 19% (n: 4). All of the isolates were sensitive to ceftazidime/avibactam and tigecycline. CONCLUSION: This study demonstrates a significant value of resistance to colistin in pediatric patients compared to other last line antimicrobial such as ceftazidime/avibactam and tigecycline.

Tipos de carbapenemasas expresadas en Klebsiella spp, y Pseudomonas aeruginosa resistente a carbapenémicos en seis hospitales de alta complejidad de la Ciudad de Bogotá - Colombia / Carbapenemases produced in Klebsiella spp, and Pseudomonas aeruginosa in six hospitals in Bogotá - Colombia

INTRODUCCIÓN: En las últimas décadas, se ha incrementado la prevalencia de infecciones por bacilos gramnegativos resistentes a carbapenémicos. OBJETIVO: Determinar los tipos y la frecuencia de las distintas carbapenemasas en aislados de Klebsiella spp. y Pseudomonas aeruginosa, en seis hospitales de alta complejidad de Bogotá-Colombia. MÉTODOS: Estudio observacional descriptivo en seis hospitales de la ciudad de Bogotá, en el período de enero de 2017 a agosto de 2018. Se realizaron RPC para genes de KPC, GES, VIM, NDM, IMP y OXA-48 en cepas de Klebsiella spp y P aeruginosa resistentes a carbapenémicos. RESULTADOS: 52 aislados de P aeruginosa amplificaron para una carbapenemasa, de los cuales 39 (75%) fueron positivos para KPC, 11 (21%) para VIM y 2 co-producciones de KPC y VIM. En cuanto a Klebsiella spp., 165 cepas amplificaron al menos para una carbapenemasa, 98% expresaron KPC y 4 aislados tuvieron co-producciones de metalo-beta-lactamasas y KPC. DISCUSIÓN: Este estudio aporta información valiosa, como el incremento de producción de KPC en P. aeruginosa y la co-producción de KPC y metalo-beta-lactamasas, locual tiene una implicancia tanto en la selección del tratamiento, las medidas de aislamiento de contacto y el pronóstico de los pacientes.

BACKGROUND: In the last decades, the prevalence of infections by carbapenem resistant gram-negative bacilli has been increased. OBJECTIVE: To determine types and frequency of the different carbapenemases in Klebsiella spp. and Pseudomonas aeruginosa, in six hospitals in Bogotá-Colombia. METHODS: Descriptive and observational study, in six hospitals in the city of Bogotá, in the period ftom January 2017 to August 2018. PCR were performed for KPC, GES, VIM, NDM, IMP and OXA-48 genes, in carbapenem resistant Klebsiella spp. and P aeruginosa. RESULTS: 52 P aeruginosa isolates amplified a carbapenemase gene, of which 39 (75%) were positive for KPC, 11 (21%) for VIM and two co-productions of KPC and VIM. Regarding Klebsiella spp. 165 strains amplified at least one carbapenemase gene, 98% expressed KPC and four isolates had co-productions of metallo-P-lactamases and KPC. DISCUSSION: This study provides valuable information, such as the increased production of KPC in P. aeruginosa información valiosa, como el incremento de producción de KPC en P. aeruginosa and the co-production of KPC plus metallobetalactamases, which has an implication both in treatment selection, isolation precautions and patient prognosisy.

Restricción programada de cefalosporinas de tercera generación en contexto de un brote de bacilos gramnegativos productores de beta-lactamasas tipo AmpC en unidades críticas: una experiencia de la vida real / Third-generation cephalosporins programmed restriction in the context of an outbreak of AmpC beta-lactamase-producing gram-negative bacilli in critical units: a real-life experience

INTRODUCCIÓN: La restricción programada (RP) de antimicrobianos puede disminuir selectivamente la tasa de infecciones por determinados microorganismos. En este sentido, los bacilos gramnegativos productores de beta-lactamasas AmpC (BGN-blaAmpC) son seleccionados por el sobreuso de cefalosporinas de tercera generación (C3G). Estas bacterias, también adquieren genes y co-producen otras beta-lactamasas, como las de Nueva Delhi (BGN-blaNDM). OBJETIVOS: Disminuir la tasa de aislamiento de BGN-blaAmpC y BGN-blaNDM en cultivos de pacientes de la UCI luego de una RP de C3G en el marco de un brote nosocomial por estos microrganismos. MATERIALES Y MÉTODOS: Estudio cuasi-experimental, previo (P1= 12 meses) y posterior (P2= 12 meses) a una RP de C3G en un hospital de adultos, donde, en el contexto de brote mencionado, se aplicaron medidas de control de infecciones generales. El uso de antimicrobianos se expresó como "porcentaje de los días de tratamiento (%DDT)"/100 camas ocupadas al día (100-COD). Se compararon las tasas de aislamiento de BGN-blaAmpC y BGN-blaNDM en hemocultivos (HC), mini-lavados bronquio-alveolares (mB) y urocultivos (UC) en la UCI. RESULTADOS: En P2 el consumo de C3G fue 2,5% DDT/100-COD. Hubo un descenso en los aislamientos de BGN-blaAmpC en HC (RR 0,48 [0,2-0,9] p < 0,02) y mB (RR 0,52 [0,3-0,9] p < 0,02), así como también de BGN-blaNDM en HC (RR 8,1 [1,6-39,4] p < 0,00). Conclusiones: La RP de C3G se asoció con la reducción de los BGN-blaAmpC y BGN-blaNDM en HC, así como de los BGN-blaAmpC mB.

BACKGROUND: Programmed restriction (PR) of antimicrobials can selectively decrease the rate of infections by certain microorganisms. In this sense, AmpC beta-lactamase-producing gram-negative bacilli (GNB-blaAmpC) are selected for the overuse of third generation cephalosporins (3GC). These bacteria also acquire genes and co-produce other β-lactamases, such as New Delhi ones (GNB-blaNDM). AIM: To decrease the isolation rate of GNB- blaAmpC and GNB- blaNDM in cultures from ICU patients after a PR of 3GC. METHODS: Quasi-experimental study, before (P1= 12 months) and after (P2= 12 months) a PR of 3GC in an adults' hospital. The use of antibiotics was expressed as "percentage days of treatment (%DOT)" /100 beds occupied per day (100-BOD). The rates of GNB-blaAmpC and GNB-blaNDM were compared in blood cultures (BC), mini-bronchio alveolar lavages (mB) and urine cultures (UC) in the ICU. RESULTS: In P2, 3GC consumption was 2.5% DOT/100-COD. There was a decrease in GNB-blaAmpC from BC (RR 0.48 [0.2-0.9] p < 0.02) and mB (RR 0.52 [0.3-0.9] p < 0.02), as well as of GNB-blaNDM from BC (RR 8.1 [1.6-39.4] p < 0.00). Conclusions: PR of 3GC was linked to the reduction of GNB-blaAmpC and GNB-blaNDM in BC, as well as GNB-blaAmpC in mB from ICU patients.

Detección fenotípica y genotípica de la producción de carbapenemasas tipo NDM-1 y KPC en enterobacterias aisladas en un laboratorio clínico en Maracay, Venezuela / Phenotypic and genotypic detection of the production of carbapenemases type NDM-1 and KPC in isolated Enterobacteriaceae in a clinical laboratory in Maracay, Venezuela

INTRODUCCIÓN: La producción de beta-lactamasas capaces de hidrolizar a los carbapenémicos es uno de los mecanismos de resistencia más preocupantes porque eliminan la última opción terapéutica frente a los microorganismos multi-resistentes. OBJETIVO: Determinar la producción de carbapenemasas tipo KPC y NDM-1, empleando métodos fenotípicos y genotípicos, en enterobacterias aisladas en un laboratorio clínico de la ciudad de Maracay, Venezuela. MÉTODOS: Se determinó la producción de carbapenemasas mediante métodos fenotípicos (según algoritmo de Malbrán) y genotípicos (amplificación de los genes blaNDM-1 y blaKPC por RPC) en enterobacterias aisladas en un laboratorio clínico durante el período marzo-agosto 2018. RESULTADOS: Se identificaron 605 enterobacterias de diferentes especies, siendo Escherichia coli la cepa con mayor porcentaje de aislamiento (61,3%), seguida por Klebsiella pneumoniae (14,9%). Diez y seis enterobacterias (2,64%) fueron positivas para la producción de carbapenemasas: 13 cepas de K. pneumoniae y tres del complejo Enterobacter cloacae. La RPC demostró que 14 cepas (87,5%) contienen el gen blaNDM-1 y dos (12,5%) el gen blaKPC; se observó 100% de concordancia entre la determinación fenotípica y la RPC para ambos grupos de enzimas. CONCLUSIONES: Los resultados mostraron mayor incidencia de la metalo-beta-lactamasa tipo NDM-1, reconocida como una alarma epidemiológica debido a que su rápida diseminación dificulta su control, por lo que la identificación del tipo de enzima permitiría establecer estrategias de manejo y control más certeras con la finalidad de erradicar a dichos patógenos.

BACKGROUND: The production of carbapenem-hydrolyzing beta-lactamases is one of the most concerning resistance mechanisms since it eliminates the last therapeutic option against multidrug resistant microorganisms. AIM: To determine the production of KPC and NDM-1 type carbapenemases, using phenotypic and genotypic methods, in isolated enterobacteria in a clinical laboratory in the city of Maracay, Venezuela. METHODS: The production of carbapenemases was determined by phenotypic (according to the Malbrán algorithm) and genotypic methods (amplification of the blaNDM-1 and blaKPC genes by PCR) in clinical isolates of Enterobacteriaceae during the period March-August 2018. RESULTS: 605 Enterobacteriaceae of different species were identified, being Escherichia coli the strain with the highest percentage of isolation (61.3%), followed by Klebsiella pneumoniae (14.9%). Sixteen strains (2.64%) were positive for carbapenemases production: 13 strains of K. pneumoniae and three of the Enterobacter cloacae complex. PCR showed that 14 strains (87.5%) carry the blaNDM-1 gene and two strains (12.5%) the blaKPC gene; 100% agreement was observed between phenotypic determination and PCR for both groups of enzymes. CONCLUSIONS: The results of this study showed a higher incidence of metallo-beta-lactamase type NDM-1, which rapid dissemination and consequently difficult control has been cause of epidemiological alert. The identification of the type of enzyme would allow establishing more accurate management and control strategies in order to eradicate these pathogens.

Caracterización de bacilos gramnegativos multi-resistentes, aislados en pacientes hospitalizados en instituciones de salud de Barranquilla (Colombia) / Characterization of multiresistant gram-negative bacilli, isolated in patients hospitalized in health institutions in Barranquilla (Colombia)

Resumen Introducción: La resistencia a carbapenémicos en bacilos gramnegativos es un problema de salud pública mundial, debido a que se asocia con altas tasas de mortalidad, aumento en los niveles de resistencia a otros antimicrobianos, elevación en el potencial de diseminación e incremento en los costos de atención en salud. Objetivo: Caracterizar bacilos gramnegativos multirresistentes, aislados en pacientes hospitalizados en instituciones de salud de Barranquilla (Colombia). Material y Métodos: Estudio descriptivo acerca de la caracterización fenotípica y genotípica de la resistencia bacteriana en las infecciones asociadas a la atención en salud, mediada por carbapenemasas en aislados bacterianos enviados por los laboratorios pertenecientes a la red de laboratorios del Departamento del Atlántico. Resultados: La KPC fue la carbapenemasa más frecuente en las Enterobacterales (27,6%), predominando en Klebsiella pneumoniae (13,1%) sola y asociada a otras carbapenemasas. En Pseudomonas aeruginosa predominó la carbapenemasa VIM (32,8%) y la OXA en Acinetobacter baumannii (17,1%). Conclusión: Se encontró una amplia distribución de cepas multi-resistentes productoras de carbapenemasas en instituciones de salud de Barranquilla, las cuales expresaron los siguientes mecanismos de resistencia: KPC, VIM, NDM, OXA.

Abstract Background: The emergence of carbapenem resistant gramnegative bacilli has become a problem of public health worldwide, because it is associated with high mortality rates, increased levels of resistance to other antimicrobials, increased potential for dissemination transition and increase in health care costs. Aim: To characterize multiresistant gram-negative bacilli, isolated in patients hospitalized in health institutions of Barranquilla (Colombia). Methods: A descriptive study was conducted on the phenotypic and genotypic characterization of bacterial resistance in infections associated with health care, mediated by carbapenemases in bacterial isolates sent by laboratories belonging to the laboratory network of the Department of Atlántico. Results: KPC was the most frequent carbapenemase in Enterobacterales (27.6%), predominantly in Klebsiella pneumoniae (13.1%) alone and associated with other carbapenemases. In Pseudomonas aeruginosa, VIM carbapenemase (32.8%) predominated and OXA in Acinetobacter baumannii (17.1%). Conclusion: A wide distribution of multi-resistant strains producing carbapenemases in Atlantic health institutions was found, which expressed the following resistance mechanisms: KPC, VIM, NDM, OXA.

First report of a blaNDM-resistant gene in a Klebsiella aerogenes clinical isolate from Brazil

Abstract INTRODUCTION: Carbapenemase-resistant enterobacteria that produce the bla NDM gene are found worldwide. However, this is the first report of blaNDM in Klebsiella aerogenes in Brazil. METHODS: The identification of bacterial species was performed using anautomated system and confirmed by biochemical tests, 16S rRNA gene sequencing, and detection of resistance genes. RESULTS: The clinical isolate showed minimum inhibitory concentration resistance to meropenem and polymyxin B at 8mg/L and 4mg/L, respectively. Only the blaNDM gene was detected. CONCLUSIONS: The current report of the blaNDM gene in isolated MDR enterobacteria indicates that this gene can spread silently in a hospital setting.

First report of the aac(6)-Ib-cr gene in Providencia stuartii isolates in Brazil

Abstract INTRODUCTION: The aac(6')-Ib-cr and bla KPC genes are spreading among Enterobacteriaceae species, including Providencia stuartii, in some countries of world. METHODS: These genes were investigated in 28 P. stuartii isolates from a public hospital in Recife, Pernambuco, Brazil, by PCR and sequencing. RESULTS: The aac(6')-Ib-cr gene was detected in 16 resistant isolates, and the bla KPC gene was seen in 14. CONCLUSIONS: The presence of these genes in P. stuartii multi- and extensively drug-resistant isolates indicates that the resistance arsenal of this species is increasing, thus limiting the therapeutic options.

Molecular epidemiology and drug resistance of Acinetobacter baumannii isolated from a regional hospital in the Brazilian Amazon region

Abstract INTRODUCTION: In this study, we report a clonal dissemination of carbapenem resistant Acinetobacter baumannii isolates due to the acquisition of blaOXA-23 in a regional hospital located in Brazilian Amazon Region. METHODS: The isolates were identified by MALDI-TOF and the carbapenemase-encoding genes were detected by multiplex-PCR. The genetic similarity was investigated by pulsed-field gel electrophoresis (PFGE). RESULTS: Only 10 (55.6%) isolates harbored the gene bla OXA-23. PFGE analysis revealed that these isolates belong to a single clone. CONCLUSIONS: This dissemination strategy indicates the need for surveillance, adoption of control procedures defined in guidelines, and the careful administration of antimicrobials should be reinforced.

Alternative Splicing Analysis of LACTB Gene and Expression Characteristics of Different Transcripts in Leukemia Cell Lines / 中国实验血液学杂志

OBJECTIVE@#To detect the expression of different transcripts of lactamase β（LACTB) gene in leukemic cell lines.@*METHODS@#NCBI website and DNAstar software were used to detect the Bioinformatics analysis of LACTB. The expression of different transcripts of LACTB gene in leukemic cell lines (THP-1, HL60, K562, U937, Jurkat and Raji) was detected by reverse transcription PCR (RT-PCR), DNA and clone sequencing; the expression of different transcripts of LACTB gene in leukemic cell lines was detected by Quantitative Real-time PCR.@*RESULTS@#There were a variety of splicing isomers in LACTB, and it could produce a variety of protein isomers with conserved N-terminal and different C-terminal, moreover, there were many splice isoforms of LACTB in leukemia cell lines, and there were different expression patterns in different cell lines, including XR1, V1, V2 and V3. The expression of total LACTB showed high in HL60 cells, while low in Raji cells, and the difference was statistically significant (P<0.05). The V1 was high expression in U937 cells but low in Raji cells, and the difference was statistically significant (P<0.05). V2 was high expression in HL60 cells but lowly in Raji cells, and the difference was statistically significant (P<0.05). The expression of V3 was low in THP-1 cells, which was significantly different as compared with that in normal bone marrow (P<0.05).@*CONCLUSION@#The reaserch found that there are many splice isomers of LACTB in leukemic cell lines, and there are different expression patterns in different cell lines.

First report of bla GES-1 in Proteus mirabilis clinical isolates

Abstract Proteus mirabilis is one of the main pathogens causing urinary tract infections and sepsis. To our knowledge, this is the first report of a P. mirabilis hosting bla GES. The presence of these genes was determined using PCR and sequencing. We identified the presence of bla GES-1 in all three isolates. In addition, we identified the bla KPC-2 and bla NDM-1 genes in the two strains. These data emphasize the importance of monitoring and surveillance of all enterobacteria. The circulation of P. mirabilis strains carrying bla GES-1 constitutes a new scenario of resistance in this species and should be an epidemiological alert for global health.

First characterization of K. pneumoniae ST11 clinical isolates harboring blaKPC-3 in Latin America / Primera caracterización de aislamientos clínicos de K. pneumoniae ST11 portadoresde blaKPC-3en América Latina

Abstract Antimicrobial resistance due to carbapenemase production in Enterobacteriaceaeclinical isolates is a global threat. Klebsiella pneumoniae harboring the blaKPCgene is one ofthe major concerns in hospital settings in Latin America.The aim of this study was to characterize the antibiotic resistance mechanisms and to typifyfour carbapenem-resistant K. pneumoniae clinical isolates from the city of Manizales, Colombia.We identified blaKPC-3in all four isolates by polymerase chain reaction and subsequentsequencing. The plasmid-mediated quinolone resistance genes qnrB19-like and aac(6)Ib-cr;fosfomycin resistance gene fosA and an insertion sequence IS5-like in mgrB (colistin resistance)were also detected. Sequence types ST11 with capsular type wzi75, and ST258 with wzi154,were characterized. The blaKPC-3gene was mobilized in a 100-kb IncFIB conjugative plasmidwith vagCD toxin-antitoxin system.This work reports multiple resistance genes in blaKPC-producing K. pneumoniae and the firstoccurrence of ST11 clinical isolates harboring blaKPC-3in Latin America.

Resumen La resistencia a antibióticos mediada por la producción de carbapenemasas en aislamientos clínicos de Enterobacteriaceae es una amenaza mundial. Klebsiella pneumoniae portador de blaKPC es uno de los mayores problemas a nivel hospitalario en Latinoamérica. El objetivo de este estudio fue caracterizar los mecanismos de resistencia antibiótica y tipificar cuatro aislamientos clínicos de K. pneumoniae resistentes a carbapenems obtenidos en la ciudad de Manizales, Colombia. Se identificó blaKPC-3 en todos los aislamientos mediante reacción en cadena de polimerasa y secuenciación. También se detectaron los genes de resistencia transferible a quinolonas qnrB19-like y aac(6')Ib-cr y a fosfomicina fosA, y la secuencia de inserción /S5-like en mgrB (asociada a la resistencia a colistina). Se caracterizaron los secuenciotipos ST11 (cápsula wzi75) y ST258 (cápsula wzi154). Se comprobó que blaKPC-3 fue movilizado por un plásmido conjugativo IncFIB-vagCD de 100kb. En este trabajo se reportan múltiples genes de resistencia en K. pneumoniae productor de blaKPC y se describen por primera vez aislamientos clínicos ST11 productores de blaKPC-3 en Latinoamérica.

Prevalence of Klebsiella pneumoniae carbapenemase - and New Delhi metallo-beta-lactamase-positive K. pneumoniae in Sergipe, Brazil, and combination therapy as a potential treatment option

Abstract INTRODUCTION: Carbapenem-resistant Klebsiella pneumoniae infection lacks treatment options and is associated with prolonged hospital stays and high mortality rates. The production of carbapenemases is one of the most important factors responsible for this multi-resistance phenomenon. METHODS: In the present study, we analyzed the presence of genes encoding carbapenemases in K. pneumoniae isolates circulating in one of the public hospitals in the city of Aracaju, Sergipe, Brazil. We also determined the best combination of drugs that display in vitro antimicrobial synergy. First, 147 carbapenem-resistant K. pneumoniae isolates were validated for the presence of blaKPC, bla GES, bla NDM, bla SPM, bla IMP, bla VIM, and bla OXA-48 genes using multiplex polymerase chain reaction. Thereafter, using two isolates (97 and 102), the role of double and triple combinational drug therapy as a treatment option was analyzed. RESULTS: Seventy-four (50.3%) isolates were positive for bla NDM, eight (5.4%) for bla KPC, and one (1.2%) for both bla NDM and bla KPC. In the synergy tests, double combinations were better than triple combinations. Polymyxin B and amikacin for isolate 97 and polymyxin B coupled with meropenem for isolate 102 showed the best response. CONCLUSIONS: Clinicians in normal practice use multiple drugs to treat infections caused by multi-resistant microorganism; however, in most cases, the benefit of the combinations is unknown. In vitro synergistic tests, such as those described herein, are important as they might help select an appropriate multi-drug antibiotic therapy and a correct dosage, ultimately reducing toxicities and the development of antibiotic resistance.

Identification of plasmid IncQ1 and NTEKPC-IId harboring bla KPC-2 in isolates from Klebsiella pneumoniae infections in patients from Recife-PE, Brazil

Abstract INTRODUCTION: This study investigated the genetic environment of bla KPC-2 in Klebsiella pnemoniae multi-drug resistant clinical isolates. METHODS: Four carbapenemase gene isolates resistant to carbapenems, collected from infected patients from two hospitals in Brazil, were investigated using polymerase chain reaction and plasmid DNA sequencing. RESULTS: The bla KPC-2 gene was located between ISKpn6 and a resolvase tnpR in the non-Tn4401 element (NTEKPC-IId). It was detected on a plasmid belonging to the IncQ1 group. CONCLUSIONS To our knowledge, this is the first report of the presence of the bla KPC-2 gene in the NTEKPC-IId element carried by plasmid IncQ1 from infections in Brazil.

High plasmid variability, and the presence of IncFIB, IncQ, IncA/C, IncHI1B, and IncL/M in clinical isolates of Klebsiella pneumoniae with bla KPC and bla NDM from patients at a public hospital in Brazil

Abstract INTRODUCTION Antibiotic resistance in carbapenemase-producing Klebsiella pneumoniae is acquired and disseminated mainly by plasmids. Therefore, we aimed to investigate the occurrence of carbapenemase genes, analyze the genetic diversity by ERIC-PCR, and examine the most common plasmid incompatibility groups (Incs) in clinical isolates of K. pneumoniae from colonization and infection in patients from a hospital in Brazil. METHODS Twenty-seven isolates of carbapenem-resistant K. pneumoniae were selected and screened for the presence of carbapenemase genes and Incs by PCR, followed by amplicon sequencing. RESULTS The bla KPC and bla NDM genes were detected in 24 (88.8 %) and 16 (59.2 %) of the isolates, respectively. Thirteen isolates (48.1 %) were positive for both genes. The IncFIB (92.6 %) and IncQ (88.8 %) were the most frequent plasmids, followed by IncA/C, IncHI1B, and IncL/M, indicating that plasmid variability existed in these isolates. To our knowledge, this is the first report of IncHI1B in Brazil. We found eight isolates with clonal relationship distributed in different sectors of the hospital. CONCLUSIONS The accumulation of resistance determinants, the variability of plasmid Incs, and the clonal dissemination detected in K. pneumoniae isolates demonstrate their potential for infection, colonization, and the dissemination of different resistance genes and plasmids.

Genetic factors related to the widespread dissemination of ST11 extensively drug-resistant carbapenemase-producing Klebsiella pneumoniae strains within hospital / 中华医学杂志(英文版)

BACKGROUND@#Carbapenemase-producing Klebsiella pneumoniae (CP-Kp) poses distinct clinical challenges due to extensively drug resistant (XDR) phenotype, and sequence type (ST) 11 is the most dominant blaKPC-2-bearing CP-Kp clone in China. The purpose of this current retrospective study was to explore the genetic factors associated with the success of XDR CP-Kp ST11 strains circulated in the intensive care unit (ICU) of a Chinese tertiary hospital.@*METHODS@#Six ST11 XDR CP-Kp strains were identified between May and December 2014 and validated by minimum inhibitory concentration examination, polymerase chain reaction, and pyrosequencing. The six ST11 XDR CP-Kp, as well as three multi-drug resistant (MDR) and four susceptible strains, were sequenced using single-molecule real-time method. Comprehensively structural and functional analysis based on comparative genomics was performed to identify genomic characteristics of the XDR ST11 CP-Kp strains.@*RESULTS@#We found that ST11 XDR blaKPC-2-bearing CP-Kp strains isolated from inpatients spread in the ICU of the hospital. Functionally, genes associated with information storage and processing of the ST11 XDR CP-Kp strains were more abundant than those of MDR and susceptible strains, especially genes correlative with mobile genetic elements (MGEs) such as transposons and prophages. Structurally, eleven large-scale genetic regions taken for the unique genome in these ST11 XDR CP-Kp strains were identified as MGEs including transposons, integrons, prophages, genomic islands, and integrative and conjugative elements. Three of them were located on plasmids and eight on chromosomes; five of them were with antimicrobial resistance genes and eight with adaptation associated genes. Notably, a new blaKPC-2-bearing ΔΔTn1721-blaKPC-2 transposon, probably transposed and truncated from ΔTn1721-blaKPC-2 by IS903D and ISKpn8, was identified in all six ST11 XDR CP-Kp strains.@*CONCLUSION@#Our findings suggested that together with clonal spread, MGEs identified uniquely in the ST11 XDR CP-Kp strains might contribute to their formidable adaptability, which facilitated their widespread dissemination in hospital.

Investigation of carbapenemases and aminoglycoside modifying enzymes of Acinetobacter baumannii isolates recovered from patients admitted to intensive care units in a tertiary-care hospital in Brazil

Abstract INTRODUCTION: Acinetobacter baumannii are opportunistic bacteria, highly capable of acquiring antimicrobial resistance through the production of carbapenemases and aminoglycoside modifying enzymes (AMEs). METHODS: Carbapenemase and AME genes were investigated in A. baumannii recovered from inpatients of a Brazilian hospital. RESULTS: The key genes found were bla OXA-51-like, the association ISAba1- bla OXA-23-like, and the AME genes aph(3´)-VI, aac(6´)-Ib, aac(3)-Ia, and aph(3´)-Ia. Different clusters spread through the institution wards. CONCLUSIONS: The dissemination of bla OXA-23-like and AME-carrying A. baumannii through the hospital highlights the need for improved preventive measures to reduce the spread of infection.

Epidemiología molecular de aislados de Acinetobacter baumannii resistentes a carbapenems en Argentina / Molecular epidemiology of carbapenem-resistant isolates of Acinetobacter baumannii in Argentina

Se estudiaron 100 aislados consecutivos y no epidemiológicamente relacionados de Acinetobacter baumannii resistentes a los carbapenems, recuperados entre enero y agosto de 2016 de muestras clínicas en 11 hospitales de 10 provincias de la Argentina, ubicadas en distintas regiones del país. Los genes que codifican las carbapenemasas de Ambler clase D y clase B se investigaron mediante la técnica de PCR utilizando cebadores específicos. Todos los aislados se agruparon mediante las técnicas de 3-locus sequence typing y la secuenciación del gen blaOXA-51-like. El gen blaOXA-23 se recuperó en todos los aislados estudiados. La población de A. baumannii resistente a carbapenems en Argentina estuvo asociada, principalmente, con ST1 (45%), ST25 (34%) y ST79 (15%). ST25 se recuperó en todas las regiones estudiadas y no se detectó CC2.

One hundred sequential, epidemiologically unrelated carbapenem-resistant- Acinetobacter baumannii isolates from 11 hospitals in 10 Argentine provinces were collected between January and August 2016. Genes coding for Ambler class D and B carbapenemases were investigated by PCR using specific primers. All isolates were typed using the 3-locus sequence typing and b/aOXA-51-like sequence-based typing techniques. The blaOXA-23 gene was recovered in all isolates studied. The population of carbapenem-resistant- A. baumannii in Argentina was principally associated with ST1 (45%), ST25 (34%) and ST79 (15%). ST25 was recovered in all the regions studied and CC2 was not detected.

Marcadores de resistencia plasmídica a quinolonas qnr en aislamientos clínicos de enterobacterias productoras de betalactamasas CTX-M en Lima, Perú / Markers of plasmid resistance to qnr quinolones in clinical isolates of CTX-M beta-lactamases-producing enterobacteria in Lima, Peru

RESUMEN Con el objetivo de reportar marcadores de resistencia plasmídica a quinolonas qnr en aislamientos clínicos de enterobacterias productoras de betalactamasas CTX-M, se realizó un estudio descriptivo, con aislamientos del cepario del proyecto TO-06/09 del Instituto Nacional de Salud del Niño. Se recuperaron 138 aislamientos. La susceptibilidad antimicrobiana se determinó por el método de disco difusión y la identificación de genes por reacción en cadena de la polimerasa. De los 138 aislados, 67 (48,5%) fueron positivos para proteínas qnr por el método genotípico. De los cuales 38 (56,7%) presentaron determinantes qnrB y 48 (71,6%) determinantes qnrS. Ningún aislado presentó determinantes qnrA. Se detectó determinantes qnr en aislamientos que presentaban betalactamasas CTX-M en una población no expuesta.

ABSTRACT Aimed at reporting markers of plasmid resistance to qnr quinolones in clinical isolates of CTX-M beta-lactamase-producing enterobacteria, a descriptive study was conducted with isolates from the strain repository of TO-06/09 project of the National Children´s Health Institute. 138 isolates were recovered. Antimicrobial susceptibility was determined by the diffusion disk method, and gene identification by polymerase chain reaction. Of the 138 isolates, 67 (48.5%) were genotypically positive for qnr proteins; of these, 38 (56.7%) had qnrB determinants and 48 (71.6%) had qnrS determinants. No isolate presented qnrA determinants. qnr determinants were detected in isolates containing CTX-M beta-lactamases in a non-exposed population.

Caracterización molecular y detección de genes blaCTX-M grupos 1 y 9 en Klebsiella pneumoniae resistentes a ceftazidima, en un hospital de San José de Cúcuta, Colombia / Molecular characterization and detection of genes blaCTX-M groups 1 and 9 in Klebsiella pneumoniae resistant to ceftazidime, in a hospital in San José de Cúcuta, Colombia

Resumen Introducción: La expresión de β-lactamasas CTX-M pertenecientes a los grupos 1 y 9 en Klebsiella pneumoniae produce grados altos de resistencia a ceftazidima, y presentan una amplia distribución mundial. Objetivo: Identificar y caracterizar los genes blaCTX-M-Grupo1 y blaCTX-M-Grupo9 en aislados de K. pneumoniae resistentes a ceftazidima en un hospital de San José de Cúcuta, Colombia. Material y Método: Se diseñaron partidores para la identificación de K. pneumoniae y los genes blaCTX-M mediante reacción de polimerasa en cadena (RPC). Posteriormente se realizó el análisis de la relación genética de estos aislados por medio de la RPC basada en secuencias repetitivas (RPC-REP). Resultados: Treinta y ocho por ciento de los 24 aislados identificados por RPC como K. pneumoniae presentaron los genes blaCTX-M-3, blaCTX-M-15 y blaCTX-M-32 (Grupo CTX-M-1) y 42% los genes blaCTX-M14, blaCTX-M-24 y blaCTX-M-27 (Grupo CTX-M-9). El análisis filogenético agrupó los aislados de K. pneumoniae en cuatro clusters, mostrando correlación en los clusters I, II y IV, al comparar los perfiles genéticos con el tipo de muestra y grupo de genes. Discusión: Se encontró una frecuencia similar de los genes blaCTX-M-Grupo1 y blaCTX-M-Grupo 9 en aislados de K. pneumoniae resistentes a ceftazidima. La correlación entre la RPC-REP con los grupos de CTX-M y el tipo de muestra reveló la presencia de tres patrones clonales.

Background: The expression of CTX-M β-lactamases belonging to groups 1 and 9 in Klebsiella pneumoniae produces high levels of resistance to ceftazidime, and they have a wide distribution worldwide. Aim: To identify and characterize the blaCTX-M-Group1 and blaCTX-M-Group9 genes in K. pneumoniae isolates resistant to ceftazidime in a hospital in San José de Cúcuta, Colombia. Material and Methods: Primers were designed for the identification of K. pneumoniae and blaCTX-M genes by PCR. Subsequently, the genetic relationship of these isolates was analyzed by REP-PCR. Results: A 38% of the 24 isolates identified by PCR as K. pneumoniae showed blaCTX-M-3. blaCTX-M-15 y blaCTX-M-32 genes (Group CTX-M-1) and 42% blaCTX-M14. blaCTX-M-24 y blaCTX-M-27 genes (Group CTX-M-9). The phylogenetic analysis grouped the K. pneumoniae isolates into 4 clusters, showing correlation in clusters I, II and IV, when comparing the genetic profiles with the type of sample and group of genes. Discussion: We found a similar frequency of blaCTX-M-Group 1 and blaCTX-M-Group 9 genes in isolates of K. pneumoniae resistant to ceftazidime. The correlation between the REP-PCR with the CTX-M groups and the type of sample revealed the presence of three clonal patterns.