Frequency of Adhesive Virulence Factor fimH among the Clinical Isolates of Acinetobacter baumannii in India

The objective of the study was to detect the presence of fimH geneamong the drug resistanst strains of Acinetobacter baumannii.fimH gene was found to be associated with a catch bond mechanism which led to better evolution of biofilm formation. Since there are not many studies done with this gene it would be a timely investigation and this study mainly aims in molecular characterizationof fimHgene among clinical isolates of A.baumannii. Semi quantitative bio adherent assay was done by the multidrug resistant strains of A.baumannii to find the formation of biofilm. The DNA was extracted with the help of kit and PCR was performed for amplification. Pearson correlation analysis was done to find the existing correlation between the fimHgene and MDR strains of A.baumanniiwith significant p-value of (<0.05). From the screened 73 genomes of MDR A.baumannii 6.8% showed positive amplicons for the fimH gene which were related to biofilm and porin formation (Fig. 1). Correlation of its existence was high in beta lactamase (100%), cephems (100%), folate (100%) resistant strains, followed by aminoglycosides (80%), carbapenems (60%) and fluoroquinolones (60%) and efflux pumps (20%). In Spite of various measures undertaken to prevent the disease, the prevalence of the pathogen is multiplying. The current study recorded the presence of fimHgene (6.8%) among the clinical isolates of A.baumannii. This gene can be used as a target to develop new drugs and vaccines to combat the menace of A.baumannii infection

Correlation of Susceptibility to Antiseptics With Biofilm-forming Properties in Acinetobacter baumannii as a Pathogen of Surgical Infection

@#The purpose of this research was to study the biofilm-forming properties of clinical strains of A.baumannii, isolated from burn wounds in patients of ICU, and their sensitivity to antiseptics. Methods: 220 clinical strains of A. baumannii isolated from intensive care unit infected burn patients were the object of the study. Antiseptic sensitivity of Acinetobacter spp. (decamethoxine, chlorhexidine, miramistin, povidone iodine) was investigated using double serial dilutions according to the standard procedure. The study of biofilm-forming properties of clinical Acinetobacter isolates was performed using the spectrophotometric technique by G.D. Christensen. In order to determine the relationship between the antiseptic sensitivity and biofilm-forming properties of A. baumannii strains, we determined the correlation coefficient (r-Pearson), the absolute value of which characterised the binding force. Results: Among 435 burn persons, who were involved in the investigated group, representatives of Acinetobacter spp. were found in 220 (50.6%), that has revealed the etiological significance of the opportunistic pathogens of Acinetobacter isolates in the development of infectious complications of burns in intensive care units. Clinical strains of A. baumannii have shown variable susceptible to decamethoxine, chlorhexidine, miramistin, povidone iodine and have been found to possess high biofilm-forming properties. The r-Pearson coefficient between sensitivity of A. baumannii to investigated antiseptics and biofilm-formation pointed out positive moderate and strong correlations. Conclusion: Biofilm-formation of Acinetobacter spp. is correlated with their susceptibility to chlorhexidine and povidone iodine strongly. However, as a more powerful antimicrobial activity of antiseptic against A. baumannii was as weaker correlation had been established.

Detection of blaoxa genes and identification of biofilmproducing capacity of Acinetobacter baumannii in a tertiary teaching hospital, Klaten, Indonesia

@#Introduction: Acinetobacter baumannii (A. baumannii) is commonly found as an agent of nosocomial infections and demonstrates a high antibiotic resistance due to its carbapenemase production. The objectives of this study were to explore the antibiotic resistance pattern, the presence of OXAs genes and the biofilm-producing capacity of A. baumannii isolated from clinical specimens.

Effects of biocide exposure on P. Aeruginosa, E. coli and A. Baumannii complex isolates from hospital and household environments / Efectos de la exposición a biocidas en aislados ambientales de P. Aeruginosa, E. coli y del complejo A. Baumannii hospitalarios y de la comunidad

Background: Bacterial responses to biocide exposure and its effects on survival and persistence remain to be studied in greater detail. Aim: To analyse the viability and survival of environmental isolates from household and hospital settings after biocide exposure. Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of chlorhexidine (CHxG), benzalkonium chloride (BAC) and triclosan (TC) were determined in isolates of Pseudomonas aeruginosa, Acinetobacter baumannii complex and Escherichia coli collected from hospital and house- holds environments. Viability was monitored after exposure and removal of biocides using agar cultures and flow cytometry. Findings: P. aeruginosa isolates showed greater tolerance for all biocides tested whereas A. baumannii complex and E. coli were less tolerant. When compared with reference strains, biocide tolerance was up to 8 to 13-fold higher for TC and BAC respectively. Flow cytometry showed that biocide exposure may induce viable but non-growing states in P. aeruginosa and E. coli isolates before becoming fully replicative. Changes in the susceptibility profile in one isolate of A. baumannii complex were observed after biocide exposure. Discussion: Bacteria isolates from hospital and households were able to recover after biocide exposure at bactericidal concentrations favouring persistence and spread of biocide-tolerant strains. This study reinforces that cleaning compliance should be monitored by non-culture based tests. Novel formulations in cleaning and disinfection protocols should be revisited in hospitals harbouring P. aeruginosa and A. baumannii multidrug resistant isolates.

Introducción: El efecto de la exposición a biocidas en las poblaciones bacterianas, su viabilidad y persistencia requieren de estudios detallados. Objetivo: analizar la viabilidad y persistencia de bacterias de ambientes hospitalarios y domésticos posterior a la exposición a biocidas. Materiales y Métodos: En un estudio experimental in vitro se determinó la concentración inhibitoria mínima (CIM) y la concentración bactericida (CBM) para chlorhexidina (CHxG), cloruro de benzalconio (BAC) y triclcosan (TC) en aislados de Pseudomonas aeruginosa (10), el complejo Acinetobacter baumannii (5) y Escherichia coli (5) obtenidos de ambientes hospitalarios y domésticos. La viabilidad y susceptibilidad bacteriana después de la exposición y remoción del biocida fue evaluada por citometria de flujo y cultivo. Resultados: Independiente de su procedencia P. aeruginosa presentó mayor tolerancia a todos los biocidas. El complejo A. baumannii y E. coli fueron hasta 8 a 13 veces más tolerantes a BAC y TC que las cepas de referencia. Se observó que la exposición a biocidas altamente efectivos induce formas viables no replicativas en P. aeruginosa y E. coli. Un aislado del complejo A baumannii presentó cambios en el perfil de susceptibilidad posterior a la exposición. Discusión: Aislados tanto de ambiente hospitalario como de la comunidad pueden recuperarse después de la exposición a concentraciones bactericidas de los biocidas favoreciendo la persistencia y diseminación de bacterias no replicativas. Por lo anterior métodos alternativos al cultivo deben utilizarse en el seguimiento de protocolos de limpieza y desinfección. Los tiempos de recuperación de la viabilidad bacteriana deben tenerse en cuenta en la formulación de protocolos para erradicar y/o controlar cepas hospitalarias de P. aeruginosa o A. baumannii multirresistentes.

Factores de riesgo en infecciones por organismos multidroga resistentes en pacientes pediátricos oncológicos en la Unidad Nacional de Oncología Pediátrica (UNOP) de Guatemala

Introducción: Las infecciones por organismos multidroga resistentes (MDR) en pacientes oncológicos pediátricos se han convertido en una causa frecuente de morbilidad y mortalidad. Objetivos: El objetivo principal de este estudio fue determinar la incidencia y los factores de riesgo para estas infecciones en una muestra de pacientes de la UNOP. Métodos: Se realizó un estudio de tipo retrospectivo. Se incluyeron pacientes de la unidad de nosocomiales con infección por organismos MDR con cultivo positivo (hemocultivo, uro cultivo, aspirado oro traqueal cultivo de secreción). Se revisaron los registros comprendidos entre 1 de enero del 2015 al 31 de diciembre del 2015; obteniendo los registros médicos de 30 pacientes que cumplían con los criterios de inclusión. Resultados: Se observó que el 60% de los pacientes con infecciones por organismo MDR son del sexo femenino, el 70% poseen el diagnóstico de un tumor hematológico y el 37% tuvieron como diagnóstico bacteriemia/sepsis, siendo la incidencia de ésta de 3.49%. Palabras Claves: factores de riesgo, Infecciones por organismos multidroga resistentes, pacientes oncológicos pediátricos. A. baumannii, K. pneumonie; cancer pediátrico.

Introduction: Multidrug resistant (MDR) organism infections in pediatric oncology patients have become a frequent cause of morbidity and mortality. The main objective of the following study was to determine the incidence and risk factors associated to MDR organisms infections in a sample of patients from UNOP. Methods: Retrospective study. The inclusion criteria were documented MDR infection with positive culture (blood, urinary, tissue or endotracheal aspirate). We reviewed medical records between January 1st, 2015 to December 31st, 2015; obtaining the medical records of 30 patients who fulfilled the inclusion criteria. Results: Sixty percent (60%) of patients female; 70% had the diagnosis of hematologic malignancy; 37% of patients were diagnosed with clinical sepsis and the incidence of sepsis was 3.49%. Key words: risk factors, infections by multidrug-resistant organisms, pediatric cancer patients. A. baumannii, K. pneumonie; pediatric cancer

Distribution of A.baumannii infections and drug resistance in Ningbo / 中国基层医药

Objective To investigate the distribution and antibiotic resistance of A.baumannii during the last five years in our hospital,the basis for the reasonable clinical use of antibiotic was provided to doctor.Methods The strains of A.baumannii isolated from clinical specimens during 2009-2013 were analyzed by VITEK-32 system,the antibiotic resistance was analyzed by WHONET5.4 software.Results A.baumannii strains were mainly isolated from sputum,accounting for 77.3％;the majority of the strains were isolated from ICU,accounting for 42.3％;the resistance rates of A.baumannii to antibiotics appeared increasing,and over 70％ except cefoperazone-sulbactam and imipenem.Conclusion A.baumannii is the major pathogen,and detection rate of A.baumannii is very high,antibiotic resistance status of A.baumannii is very serious.The management of antibiotic application should be strengthened,and the occurrence and prevalence of antibiotic resistant bacteria should be strictly controlled to prevent outbreak and epidemic of nosocomial infection.

Infección por Acinetobacter spp. en Hospital Universitario Clínico Quirúrgico Comandante Faustino Pérez Hernández de Matanzas: 2011-2012 / Infection by Acinetobacter spp. in the University Hospital Comandante Faustino Pérez Hernández of Matanzas: 2011-2012

Las infecciones asociadas a la asistencia sanitaria constituyen un grave problema de la salud pública a nivel mundial por su frecuencia y elevada mortalidad. El Acinetobacter spp. en la última década ha emergido como importante patógeno oportunista nosocomial. Dentro de estas especies, A. baumanii es la principal especie que se aisla hasta en 92 por ciento de las bacteriemias nosocomiales. La mayoría de los reportes de bacteriemia nosocomial por A. baumanii (B Ab) son de brotes en unidades de cuidados intensivos de pacientes adultos. Se ha reportado el incremento de la resistencia a antimicrobianos de este germen. Se realizó un estudio observacional descriptivo transversal acerca de la infección por Acinetobacter spp. en el Hospital Universitario Clínico Quirúrgico Comandante Faustino Pérez Hernández, del municipio de Matanzas, entre los meses de octubre de 2011 a julio de 2012. Teniendo en cuenta la ausencia de un estudio anterior en Matanzas sobre infección por este microorganismo, se decidió identificar la incidencia de Acinetobacter spp. según muestra biológica y servicio de procedencia e identificar la sensibilidad/resistencia del mismo, lo cual permitirá instaurar un tratamiento eficaz a los pacientes portadores de esta bacteria atendiendo al patrón de susceptibilidad encontrado en el estudio. La especie más frecuente fue A. baumanii, fundamentalmente en secreción endotraqueal y hemocultivo, procedentes en su mayoría de UTI, siendo este servicio el que aportó más cantidad de cepas MDR. Se encontró una mayor sensibilidad a antimicrobianos no considerados de primera línea como doxiciclina, tetraciclina y trimetropim-sulfametoxazol.

Infections associated to the sanitary care are serious public health problems at the international level because of their frequency and high mortality. In the last ten years, Acinetobacter spp. has emerged as an important nosocomial opportunistic pathogen. Among these species, A. baumanii (B Ab) is the main isolated species covering as many as 92 per cent of the nosocomial bacteremias. Most of the reports of nosocomial bacteremias by A. baumanii (B Ab) are outbreaks in adult patient intensive care units. It has been reported a boost of this germ antimicrobial resistance. We carried out a cross sectional, descriptive, observational study on Acinetobacter spp. infection, in the University Hospital Comandante Faustino Pérez Hernández of Matanzas municipality, from October 2011 to July 2012. Taking into account the absence of a previous study in Matanzas on infections caused by this microorganism, we decided identifying the Acinetobacter spp. incidence according to biological samples and coming-from service and identifying its sensibility/resistance, allowing the instauration of the efficacious treatment of the patients who carry this bacterium, considering the susceptibility pattern found in the study. The most frequently found species was A. baumanii, mainly in endotracheal secretions and hemo-cultures, most of them coming from Intensive Therapy Units, being this service the one contributing with more quantity of multidrug resistant stocks. We found a bigger sensibility to antimicrobials that are not considered first line ones like doxycycline, tetracycline and trimetoprim-sulfametoxazole.

Dissemination of an AbaR-type Resistance Island in Multidrug-resistant Acinetobacter baumannii Global Clone 2 in Daejeon of Korea / 대한임상미생물학회지

BACKGROUND: Acinetobacter baumannii resistance islands (AbaRs) are transposons that have the role of important vehicles for the acquisition of antimicrobial resistance genes, and are associated with multidrug resistance (MDR). In this study, we aimed to determine the AbaRs in MDR A. baumannii global clone 2 (GC2) clinical isolates obtained from a university hospital in Daejeon, Korea. METHODS: This study included 17 MDR A. baumannii strains isolated in Daejeon, Korea. The minimal inhibitory concentrations (MICs) were determined by Etest. A. baumannii isolates were characterized using 2 multiplex PCR assays and a multilocus sequence typing (MLST) scheme. To detect and characterize AbaRs, PCR and PCR mapping experiments were performed. RESULTS: All 17 MDR A. baumannii isolates tested in this study belonged to GC2 and contained 5 sequence types (STs): 75, 92, 137, 138, and 357. Tn6166 that contains antimicrobial resistance genes and is also known as AbaR4a was found in all 17 GC2 strains. This is the first report of Tn6166 in MDR A. baumannii GC2 isolates in Korea. In contrast, AbaR4 was not found in the GC2 isolates. CONCLUSION: Tn6166 has been disseminated among MDR A. baumannii GC2 isolates in Korea. Further investigation is needed to recover the various types of AbaRs in MDR A. baumannii GC2 isolates in Korea are responsible for the multiple antimicrobial resistance mechanisms.

AbaR7, a Genomic Resistance Island Found in Multidrug-resistant Acinetobacter baumannii Isolates in Daejeon, Korea

BACKGROUND: Acinetobacter baumannii resistance islands (AbaRs) have been recently recognized as mobile genetic elements that harbor multiple resistance determinants and are associated with multidrug resistance (MDR). In the present study, we aimed to determine the AbaRs conferring multiple antimicrobial resistance and their clonal relatedness to MDR A. baumannii clinical isolates obtained from a university hospital in Daejeon, Korea. METHODS: This study included 29 MDR A. baumannii strains isolated in Daejeon, Korea. The minimal inhibitory concentrations (MICs) were determined by Etest. A. baumannii isolates were characterized using the 2 multiplex PCR assays and multilocus sequence typing (MLST) scheme. To detect and characterize AbaRs, PCR and PCR mapping experiments were performed. RESULTS: Twenty-seven of the 29 isolates belonged to the European (EU) clone II lineage and contained 5 sequence types (STs) (75, 92, 137, 138, and 357). In this study, ST357 was confirmed for the first time in Korea. Only 2 of the 29 isolates belonged to the EU clone I lineage, and were confirmed as ST109. These 2 isolates harbored the 22-kb AbaR7 aacC1-orfP-orfQ-aadA1 gene cassette array. In contrast, AbaR was not found in EU clone II isolates. CONCLUSIONS: This is the first study that attempted to determine the AbaRs in MDR A. baumannii isolates in Korea. We found 2 EU clone I isolates (ST109) that harbored AbaR7.

AbaR7, a Genomic Resistance Island Found in Multidrug-resistant Acinetobacter baumannii Isolates in Daejeon, Korea

BACKGROUND: Acinetobacter baumannii resistance islands (AbaRs) have been recently recognized as mobile genetic elements that harbor multiple resistance determinants and are associated with multidrug resistance (MDR). In the present study, we aimed to determine the AbaRs conferring multiple antimicrobial resistance and their clonal relatedness to MDR A. baumannii clinical isolates obtained from a university hospital in Daejeon, Korea. METHODS: This study included 29 MDR A. baumannii strains isolated in Daejeon, Korea. The minimal inhibitory concentrations (MICs) were determined by Etest. A. baumannii isolates were characterized using the 2 multiplex PCR assays and multilocus sequence typing (MLST) scheme. To detect and characterize AbaRs, PCR and PCR mapping experiments were performed. RESULTS: Twenty-seven of the 29 isolates belonged to the European (EU) clone II lineage and contained 5 sequence types (STs) (75, 92, 137, 138, and 357). In this study, ST357 was confirmed for the first time in Korea. Only 2 of the 29 isolates belonged to the EU clone I lineage, and were confirmed as ST109. These 2 isolates harbored the 22-kb AbaR7 aacC1-orfP-orfQ-aadA1 gene cassette array. In contrast, AbaR was not found in EU clone II isolates. CONCLUSIONS: This is the first study that attempted to determine the AbaRs in MDR A. baumannii isolates in Korea. We found 2 EU clone I isolates (ST109) that harbored AbaR7.

Multiresistance and endemic status of acinetobacter baumannii associated with nosocomial infections in a tunisian hospital: a critical situation in the intensive care units

Acinetobacter baumannii is often implicated in hospital outbreaks in Tunisia. It's a significant opportunistic pathogen associated with serious underlying diseases such as pneumoniae, meningitis and urinary tract infections. The aim of our study was to evaluate its degree of endemicity and its antibiotic resistance evolution essentially in the unit care where its isolation was predominant (57 percent). This study used 3 methods: antibiotyping, RAPD using 2 primers VIL 1, VIL5 and PFGE with ApaI restriction enzyme. The presence of integron1 and 2 was also studied. Antibiotyping showed that 92 percent of patients were resistant of all ß- lactams (except Imipenem) and that the resistance to Imipenem occurred in 47 percent of cases. RAPD profiles obtained with the 2 arbitrarily primers VIL1 and VIL5 gave respectively 5 and 4groups and PFGE fingerprinting patterns revealed 22 different pulsotypes. Integron 1 was present in 25 percent of unrelated strains and type 2 integron was not detected in any of the studied strains. Among 204 strains, multiple and heterogeneous groups were detected with the genomic studies. In addition, any correlation was obtained with the antibiotyping results. These findings demonstrate the endemic status of A. baumannii in our hospital and the persistence of a large number of multiresistant strains in the unit's care. When outbreaks of A. baumannii occur, it's essential to develop restricted hygiene procedures and a serious surveillance of critical units such as ICU for very ill patients.

Mutación en el gen gyrA de aislamientos hospitalarios de Acinetobacter baumannii en Montería, Colombia / Mutation of the gyrA Gen in Acinetobacter baumannii nosocomial isolates in Monteria, Colombia

Objetivo: Determinar las mutaciones delgen gyrA asociadas con la resistencia a fluoroquinolonas en Acinetobacter baumannii. Materiales y métodos: Entre agosto de 2005 y febrero de 2007 se recolectaron 23 aislamientos de A. baumannii de una clínica privada de tercer nivel de Montería. Se investigaron los genes gyrA, parC y adeB; este último codifica para la bomba de salida. Se realizó secuenciación del ADN y, para elanálisis de las secuencias, se usaron la base de datos GenBank y el motor de búsqueda BLASTX. Resultados: La amplificación del gen gyrA en aislamientos de A. baumannii generó unfragmento de 343 pb, el cual presentó pérdida del sitio de restricción con la enzima Hinfl en 12/23 (52,1%) de los aislamientos resistentes a fluoroquinolonas. La secuenciacióndel fragmento mostró mutación puntual con el cambio de Ser-83 a Leu, código de acceso GenBank EU886740. No se encontraron mutaciones en el gen parC, ni la presencia de la bomba de salida Ade. Conclusión: Los aislamientos de A. baumannii resistentes a fluoroquinolonas sugieren que la mutación del gen gyrA que codifica elcambio del aminoácido serina a leucina en el codón 83 de estos aislamientos, es responsable o, al menos, contribuye con la resistencia expresada a las fluoroquinolonas.

Objective: Determine mutations in thegyrA gene associated to resistance tofluoroquinolones in A. baumannii. Materials and methods: From August,2005 to February, 2007, 23 A. baumanniiisolates were collected in a third level private clinic in Monteria. Research on gyrA, parC and AdeB genes was carried out, and the latter encodes for the efflux pump. DNA sequencing was performed, and the GenBank database and BLASTX search engine were used for sequence analysis. Results: Amplification of the gyrA gene in A. baumannii isolates generated a 343pb fragment which presented loss of restriction site with the enzyme HinfI in 12/23 (52.1%) of the isolates resistant to fluoroquinolones. The fragment sequencing showed mutationcharacterized by the change of Ser-83 to Leu GenBank acces code EU886740. None of the isolates showed mutations in the parC gene or presence of the AdeB efflux pump. Conclusion: The A. baumannii isolates resistant to fluoroquinolones suggest thatmutation of the gyrA gene encoding the serine amino acid change to leucine at codon 83 of these isolates is responsible or at least contributes to the mentioned resistance to fluoroquinolones.

Genetic Basis of Multidrug-resistant Acinetobacter baumannii Clinical Isolates from Three University Hospitals in Chungcheong Province, Korea / 대한진단검사의학회지

BACKGROUND: The emergence of multidrug-resistant (MDR) Acinetobacter baumannii as an important opportunistic pathogen has given rise to significant therapeutic challenges in the treatment of nosocomial infections. In the present study, we assess the antibiotic resistance mechanisms of MDR A. baumannii strains by estimating the prevalence of antibiotic resistance determinants, including integrons, beta-lactamases, str genes, and gyrA and parC mutations. METHODS: Thirty-five MDR A. baumannii clinical isolates were collected from 3 Korean university hospitals over a 2-yr period. A. baumannii was confirmed by rpoB gene analysis. For each isolate, the minimal inhibitory concentrations (MICs) of 9 antibiotics were determined by the agar dilution method. PCR and DNA sequencing were used to identify the genes that potentially contribute to each resistance phenotype. RESULTS: Of the 35 MDR A. baumannii isolates examined, 7 antibiotic resistance gene determinants were detected. These resistance gene determinants included the gene bla(OXA-23), with an upstream element ISAba1 to promote increased gene expression and subsequent resistance to carbapenems, in 8 isolates (22.9%); aacA4, located within class 1 integrons, in 7 isolates (20.0%); and fluoroquinolone resistance conferred by gyrA and parC sense mutations in 31 isolates. CONCLUSIONS: Of the 35 MDR A. baumannii isolates, 26 (74.3%) from both outbreak and sporadic cases possessed at least 4 of the 7 antibiotic resistance gene determinants that give rise to the MDR phenotype. The co-occurrence of several resistance determinants may present a significant threat.

Genotipificación de Acinetobacter baumannii multi-resistente aislado en el hospital Dr. Domingo Luciani de caracas / Genotypification of multiresistant Acinetobacter baumannii isolated in the Dr. Domingo Luciani Hospital of caracas

Las técnicas de genotipificación tienen un rol fundamental en el estudio de las infecciones nosocomiales. Las infecciones nosocomiales son producidas principalmente por microorganismos que son resistentes a los antimicrobianos, que por lo general han sido seleccionados por el uso inadecuado de la terapia antimicrobiana. Entre las especies que causan frecuentemente este tipo de infecciones se encuentra A. baumannii multi-resistente. En esta investigación se planteó genotipificar mediante las técnicas ERIC-PCR y REP-PCR 19 cepas de A. baumannii multi-resistente aisladas en el hospital Dr. Domingo Luciani de Caracas. La confirmación molecular de la especie A. baumannii se realizó mediante la detección de la oxacilinasa OXA 51 por PCR, el 100% de los aislados incluidos en el estudio resultaron positivos para la detección del gen blaOXA-51-Like. La susceptibilidad antimicrobiana y la detección fenotípica de mecanismos de resistencia se efectuaron de acuerdo a las normas de la CLSI 2009. Se determinó policlonalidad en los 19 aislados de A. baumannii, con el predominio de cuatro clones en la Unidad de Terapia Intensiva de Adultos y el área de Hospitalización del Hospital Dr. Domingo Luciani de Caracas. La correlación de los datos epidemiológicos con las características de la resistencia y la información molecular de cada una de las muestras permitió identificar dos patrones de infección: infecciones de origen endógeno, las cuales se caracterizaron por la diversidad genética de los aislamientos, e infecciones cruzadas, debido al hallazgo de cepas estrechamente relacionadas en espacios cercano o distantes del centro de salud. Se demostró que ERIC-PCR y REP-PCR bajo las condiciones estandarizadas en este estudio son técnicas confiables desde el punto de vista de la estabilidad de los marcadores moleculares y la reproducibilidad para caracterizar brotes ocasionados por A. baumannii, considerándose la técnica REP-PCR más adecuada para estudios de genotipificación...

The genotypification techniques have a fundamental role in the study of nosocomial infections. These infections are produced principally by microorganisms that are antimicrobial resistant, that have benn selected by the inadequate use of antimicrobial therapy. Between the species that frequently cause these type of infections is the A baumannii multi-resistant. In this investigation we established to genotypificate by ERIC-PCR y REP-PCR techniques 19 strains of A baumannii multi-resitant isolated in the Dr. Domingo Luciani Hospital of Caracas. The molecular confirmation of the species was realized by the detection of the oxacilianse OXA 51 by PCR. 100% of the isolates included in the study resulted positive for the gen bla OXA-51-Like. The antimocrobial susceptibility and the phenotypic detection of resistance mechanism were done according the CLSI 2009 normative. We determined policlonality on the 19 isolates of A. baumannii, with the predominance of 4 clones in the Intensive Therapy unit and the hospitalization area of the hospital. The correlation of the epidemiological data with the resistance characteristics and the molecular information of each sample allowed us to identificate two patterns of infections: endogen origin infection, which was charaterized by the genetic diversity of the isolates and cross infections, due to the finding of strains closely related in spaces near o distant ffrom the health center. We demostrated that ERIC-PCR and REP-PCR under standarized conditions in this study are good techiques fron the point of view of the stability of the molecular markers and the reproducibility to characterize outbreaks occasioned by A. baumannii, consideratin the REP-PCR technique, the most adequate for genotypification of this strain.

Dissemination of IMP-1 and OXA Type beta-Lactamase in Carbapenem-resistant Acinetobacter baumannii / 대한진단검사의학회지

BACKGROUND: Acinetobacter baumannii is an aerobic, gram-negative, glucose-nonfermenting bacterium, which has emerged as a serious opportunistic pathogen. In recent years, the increasing instance of carbapenem-resistant A. baumannii producing metallo-beta-lactamases (MBLs) or OXAtype beta-lactamases is causing a serious clinical problem. In this study, we investigated the prevalence of Ambler class A, B, and D beta-lactamases and their extended-spectrum derivatives in carbapenem-resistant A. baumannii isolates. METHODS: A total of 31 consecutive, non-duplicate, carbapenem-resistant A. baumannii were isolated from three university hospitals in the Chungcheong province of Korea. The modified Hodge and inhibitor-potentiated disk diffusion tests were conducted for the screening of carbapenemase and MBL production, respectively. PCR and DNA sequencing were performed for the detection of beta-lactamase genes. We also employed the enterobacterial repetitive intergenic consensus (ERIC)-PCR method for the epidemiologic study. RESULTS: Twenty-three of 31 isolates harbored bla(OXA-2) (51.6%), bla(OXA-23) (22.6%), bla(IMP-1) (48.4%),and bla(VIM-2) (3.2%). All of the OXA-2-producing strains also evidenced MBLs. The strains that harbored bla(OXA-23) were isolated only in hospital C, and only in a limited fashion. The ERIC-PCR pattern of the five OXA-23 strains indicated that the isolates were closely related in terms of clonality. The six strains producing IMP-1 isolated from hospital A were confirmed to be identical strains. CONCLUSIONS: A. baumannii strains harboring IMP-1 or OXA-type beta-lactamases are currently widely distributed throughout the Chungcheong province of Korea. The most notable finding in this study was that a bla(OXA-2)-producing A. baumannii harboring MBL, which has not been previously reported, can also lead to outbreaks.

A Comparison of ID 32 GN System with Amplified Ribosomal DNA Restriction Analysis for Identification of Acinetobacter baumannii / 대한진단검사의학회지

BACKGROUND: The glucose -acidifying genomic species 1, 2, 3 and 13 of the genus Acinetobacter are highly related genetically and may be difficult to differentiate by phenotypic identification schemes using biochemical tests. The aim of this study was to explore the brief restriction enzyme profiles of amplified ribosomal DNA restriction analysis (ARDRA) to identify medically important species of Acinetobacter. Using ARDRA analysis, we evaluated the ID 32 GN system (bioMerieux, Lyon, France) for the identification of A. baumannii (genospecies 2). METHODS: A collection of 78 A. baumannii stains initially identified by the ID 32 GN system was used to determine its accuracy by ARDRA analysis. ARDRA was performed with 10 different restriction enzymes, AluI (AGCT), CfoI (GCGC), HaeIII (GGCC), HinfI (GANTC), MboI (GATC), MspI (CCGG), NciI (CCGG), RsaI (GTAC), ScrFI (CCNGG) and TaqI (TCGA). RESULTS: The combination of restriction patterns obtained with respective enzymes AluI, CfoI and MboI allowed for the discriminatory value for the identification of medically important genospecies such as genospecies 2 (A. baumannii), 3 and 13. By comparing ARDRA results of the 78 strains previously identified by ID 32 GN system, we found the correlation rate between the two systems to be 88.5% (69/78). Nine strains were identified as Acinetobacter genospecies 13 by ARDRA. CONCLUSIONS: This result suggests that the ID 32 GN system may have difficulty in discriminating A. baumannii from genospecies 13. This revised ARDRA method gives a relatively rapid and definitive result for the identification of medically important genospecies of Acinetobacter.

Integron Carriage in Multiresistant Acinetobacter baumannii Strains

One hundred and eight Acinetobacter baumannii strains isolated from three university hospitals in Korea were investigated for the presence of integrons and its correlation with multiple antibiotic resistance. A. baumannii strains were classified into 23 different groups based on the biochemical tests, RAPD patterns, and antibiotic susceptibility. Many strains isolated from same hospital showed identical epidemiological markers: 75% of isolates from Gwangju, 53% from Seoul, and 39% from Cheonan appeared identical. Integrase genes were detected in 79 (73%) A. baumannii isolates. The intI1 and intI2 genes were detected in 73 (68%) and 10 (9%) isolates, respectively. Class 3 integrons were not detected. Integrase genes were detected in A. baumannii isolates from Gwangju and Seoul, but not in the strains from Cheonan. Based on the epidemiological grouping, most of A. baumannii strains affecting four or more patients carried integrons, while only one strain among the sporadic strains carried a class 2 integron. Integron-carrying A. baumannii strains were resistant to more antibiotics compared to the integron-negative strains. This result suggests that integron-carrying A. baumannii strains are more apt to spread nosocomially and to show multiple antibiotic resistances.