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1.
Rev. Soc. Bras. Med. Trop ; 53: e20190044, 2020. tab
Article in English | LILACS | ID: biblio-1057279

ABSTRACT

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.


Subject(s)
Humans , Bacterial Proteins/genetics , beta-Lactamases/genetics , Acinetobacter Infections/microbiology , Acinetobacter baumannii/enzymology , Aminoglycosides/genetics , Brazil , Microbial Sensitivity Tests , Drug Resistance, Multiple, Bacterial , Acinetobacter baumannii/isolation & purification , Acinetobacter baumannii/drug effects , Tertiary Care Centers , Intensive Care Units , Anti-Bacterial Agents/pharmacology
2.
Braz. j. microbiol ; 48(4): 637-647, Oct.-Dec. 2017. tab, graf
Article in English | LILACS | ID: biblio-889185

ABSTRACT

ABSTRACT Role of microbes in bioremediation of oil spills has become inevitable owing to their eco friendly nature. This study focused on the isolation and characterization of bacterial strains with superior oil degrading potential from crude-oil contaminated soil. Three such bacterial strains were selected and subsequently identified by 16S rRNA gene sequence analysis as Corynebacterium aurimucosum, Acinetobacter baumannii and Microbacterium hydrocarbonoxydans respectively. The specific activity of catechol 1,2 dioxygenase (C12O) and catechol 2,3 dioxygenase (C23O) was determined in these three strains wherein the activity of C12O was more than that of C23O. Among the three strains, Microbacterium hydrocarbonoxydans exhibited superior crude oil degrading ability as evidenced by its superior growth rate in crude oil enriched medium and enhanced activity of dioxygenases. Also degradation of total petroleum hydrocarbon (TPH) in crude oil was higher with Microbacterium hydrocarbonoxydans. The three strains also produced biosurfactants of glycolipid nature as indicated d by biochemical, FTIR and GCMS analysis. These findings emphasize that such bacterial strains with superior oil degrading capacity may find their potential application in bioremediation of oil spills and conservation of marine and soil ecosystem.


Subject(s)
Soil Pollutants/metabolism , Surface-Active Agents/metabolism , Bacterial Proteins/metabolism , Petroleum/microbiology , Actinobacteria/metabolism , Corynebacterium/metabolism , Acinetobacter baumannii/metabolism , Dioxygenases/metabolism , Phylogeny , Soil Microbiology , Surface-Active Agents/chemistry , Bacterial Proteins/genetics , Biodegradation, Environmental , Petroleum/analysis , Petroleum Pollution/analysis , Actinobacteria/growth & development , Actinobacteria/enzymology , Actinobacteria/genetics , Corynebacterium/growth & development , Corynebacterium/enzymology , Corynebacterium/genetics , Acinetobacter baumannii/growth & development , Acinetobacter baumannii/enzymology , Acinetobacter baumannii/genetics , Dioxygenases/genetics , India
3.
Rev. Soc. Bras. Med. Trop ; 50(2): 167-172, Mar.-Apr. 2017. tab
Article in English | LILACS | ID: biblio-842841

ABSTRACT

Abstract INTRODUCTION: Acinetobacter baumannii is a major pathogen causing infections in intensive care units (ICUs). In this study, we aimed to evaluate the presence of A. baumannii in an ICU environment and gloves from ICU workers and to characterize the antimicrobial resistance of the isolates in comparison with those isolated from ICU patients at the same hospital. METHODS: ICU samples were collected from March to November 2010. Isolates biochemically characterized as Acinetobacter calcoaceticus-Acinetobacter baumannii complex were evaluated by PCR targeting the 16S rDNA and bla OXA-51 genes. Antimicrobial susceptibility was determined using the disk diffusion method, and carbapenem-resistant isolates were also evaluated for the minimum inhibitory concentration of imipenem using broth microdilution. The presence of the bla OXA-23 gene was evaluated in isolates with reduced susceptibility to carbapenems. RESULTS: A. baumannii was detected in 9.5% (84) of the 886 samples collected from the ICU environment, including from furniture, medical devices, and gloves, with bed rails being the most contaminated location (23.8%; 20/84). Multidrug-resistant (MDR) A. baumannii was found in 98.8% (83/84) of non-clinical and 97.8% (45/46) of clinical isolates. Reduced susceptibility to carbapenems was detected in 83.3% (70/84) of non-clinical and 80.4% (37/46) of clinical isolates. All isolates resistant to carbapenems harbored bla OXA-23. CONCLUSIONS: We found a strong similarity between the antimicrobial susceptibility profiles of non-clinical and clinical A. baumannii isolates. Such data highlight the ICU environment as a potential origin for the persistence of MDR A. baumannii, and hence the ICU may be a source of hospital-acquired infections caused by this microorganism.


Subject(s)
Humans , Carbapenems/pharmacology , Polymerase Chain Reaction , Gloves, Protective/microbiology , Acinetobacter baumannii/drug effects , Environmental Microbiology , Equipment and Supplies, Hospital/microbiology , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial , Acinetobacter baumannii/isolation & purification , Acinetobacter baumannii/enzymology , Disk Diffusion Antimicrobial Tests
4.
Braz. j. infect. dis ; 20(6): 556-563, Nov.-Dec. 2016. tab
Article in English | LILACS | ID: biblio-828166

ABSTRACT

ABSTRACT Background: Carbapenem-resistant Acinetobacter baumannii (CRAb) is an important cause of nosocomial infections especially in intensive care units. This study aimed to assess clinical aspects and the genetic background of CRAb among ICU patients at a Brazilian teaching hospital. Methods: 56 critically ill patients colonized or infected by CRAb, during ICU stay, were prospectively assessed. Based on imipenem MIC ≥ 4 µg/mL, 28 CRAB strains were screened for the presence of genes encoding metallo-β-lactamases and OXA-type β-lactamases. The blaOXA-type genes were characterized by PCR using primers targeting ISAba-1 or -3. Genetic diversity of blaOXA-positive strains was determined by ERIC-PCR analysis. Results: Patient's mean age (±SD) was 61 (±15.1), and 58.9% were male. Eighty-percent of the patients presented risk factors for CRAb colonization, mainly invasive devices (87.5%) and previous antibiotic therapy (77.6%). Thirty-three patients died during hospital stay (59.0%). Resistance to carbapenems was associated with a high prevalence of blaOXA-23 (51.2%) and/or blaOXA-143 (18.6%) genes. ERIC-PCR genotyping identified 10 clusters among OXA-producing CRAb. Three CRAb strains exhibited additional resistance to polymyxin B (MIC ≥ 4 µg/mL), whereas 10 CRAb strains showed tigecycline MICs > 2 µg/mL. Conclusions: In this study, clonally unrelated OXA-123- and OXA-143-producing A. baumannii strains in ICU patients were strongly correlated to colonization with infected patients being associated with a poor outcome.


Subject(s)
Humans , Male , Female , Middle Aged , beta-Lactamases/biosynthesis , Acinetobacter Infections/microbiology , Cross Infection/microbiology , Acinetobacter baumannii/enzymology , Anti-Bacterial Agents/pharmacology , beta-Lactamases/genetics , Brazil , Microbial Sensitivity Tests , Prospective Studies , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/genetics , Multiplex Polymerase Chain Reaction , Genotype , Hospitals, Teaching , Intensive Care Units
5.
Mem. Inst. Oswaldo Cruz ; 111(9): 597-598, Sept. 2016.
Article in English | LILACS | ID: lil-794727

ABSTRACT

Over the last decade, Acinetobacter baumannii resistant to carbapenems has emerged in many medical centres and has been commonly associated with high morbimortality. In Brazil, this resistance is mainly attributed to the spread of OXA-23-producing clones and, to a lesser extent, to OXA-143-producing clones. Here, we describe, for the first time, two OXA-72-producing A. baumannii isolates in southern Brazil to a broad spectrum of antibiotics, except polymyxin B and tigecycline. Molecular typing by multilocus sequence typing (MLST) demonstrated that both OXA-72-producing isolates belong to a new sequence type (ST), ST730, which was recently identified in OXA-23-producing A. baumannii isolates in São Paulo, Brazil. We demonstrate that the two A. baumannii ST730 isolates carrying blaOXA-72share a common ancestral origin with the blaOXA-23producers in Brazil. This observation reinforces the importance of strain-typing methods in order to clarify the dynamics of the emergence of new clones in a geographic region.


Subject(s)
Humans , Male , Aged , Acinetobacter baumannii/genetics , beta-Lactamases/genetics , Genes, Bacterial/genetics , Acinetobacter baumannii/enzymology , Bacterial Proteins/genetics , Brazil , Drug Resistance, Bacterial/genetics , Multilocus Sequence Typing
6.
Rev. Soc. Bras. Med. Trop ; 48(6): 699-705, Nov.-Dec. 2015. tab, graf
Article in English | LILACS | ID: lil-767825

ABSTRACT

Abstract: INTRODUCTION: Carbapenems are the therapy of choice for treating severe infections caused by the Acinetobacter calcoaceticus-Acinetobacter baumannii complex. We aimed to assess the prevalence and antimicrobial susceptibility profiles of producers of distinct oxacillinases among nosocomial isolates of the A. calcoaceticus-A. baumannii complex in a 249-bed general hospital located in Joinville, Southern Brazil. METHODS: Of the 139 A. baumannii clinical isolates with reduced susceptibility to carbapenems between 2010 and 2013, 118 isolates from varying anatomical sites and hospital sectors were selected for genotypic analysis. Five families of genes encoding oxacillinases, namely blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, blaOXA-58-like, and blaOXA-143-like, wereinvestigated by multiplex polymerase chain reaction (PCR). RESULTS: Most (87.3%) isolates simultaneously carried the blaOXA-23-likeand blaOXA-51-likegenes, whereas three (2.5%) isolates harbored only blaOXA-51-likeones. The circulation of carbapenem-resistant isolates increased during the study period: from none in 2010, to 22 in 2011, 64 in 2012, and 53 in 2013. CONCLUSIONS: Isolates carrying the blaOXA-23-likeand blaOXA-51-likegenes were widely distributed in the hospital investigated. Because of the worsening scenario, the implementation of preventive measures and effective barriers is needed.


Subject(s)
Humans , Acinetobacter Infections/microbiology , Acinetobacter baumannii/drug effects , Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Cross Infection/microbiology , beta-Lactamases/genetics , Acinetobacter baumannii/enzymology , Acinetobacter baumannii/genetics , Brazil , Disk Diffusion Antimicrobial Tests , Genotype , Multiplex Polymerase Chain Reaction , Phenotype , beta-Lactamases/drug effects
7.
Braz. j. infect. dis ; 19(4): 350-357, July-Aug. 2015. tab
Article in English | LILACS | ID: lil-759271

ABSTRACT

Background:In Brazil, ventilator-associated pneumonia (VAP) caused by carbapenem resis- tant Acinetobacter baumanniiand Pseudomonas aeruginosaisolates are associated with significant mortality, morbidity and costs. Studies on the clonal relatedness of these isolates could lay the foundation for effective infection prevention and control programs.Objectives: We sought to study the epidemiological and molecular characteristics of A. baumannii vs. P. aeruginosaVAP in an adult intensive care unit (ICU).Methods: It was conducted a cohort study of patients with VAP caused by carbapenem resistant A. baumanniiand P'. aeruginosaduring 14 months in an adult ICU. Genomic studies were used to investigate the clonal relatedness of carbapenem resistant OXA-23-producing A. baumanniiand P. aeruginosaclinical isolates. The risk factors for acquisition of VAP were also evaluated. Clinical isolates were collected for analysis as were samples from the environment and were typed using pulsed field gel electrophoresis.Results: Multivariate logistic regression analysis identified trauma diagnosed at admission and inappropriate antimicrobial therapy as independent variables associated with the development of A. baumanniiVAP and hemodialysis as independent variable associated with P. aeruginosaVAP. All carbapenem resistant clinical and environmental isolates of A. baumanniiwere OXA-23 producers. No MBL-producer P. aeruginosawas detected. Molecular typing revealed a polyclonal pattern; however, clone A (clinical) and H (surface) were the most frequent among isolates of A. baumanniitested, with a greater pattern of resistance than other isolates. In P. aeruginosathe most frequent clone I was multi-sensitive.Conclusion: These findings suggest the requirement of constant monitoring of these microor- ganisms in order to control the spread of these clones in the hospital environment.


Subject(s)
Adult , Female , Humans , Male , Middle Aged , Acinetobacter Infections/microbiology , Drug Resistance, Multiple, Bacterial/genetics , Pneumonia, Ventilator-Associated/microbiology , Pseudomonas Infections/microbiology , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/enzymology , Acinetobacter baumannii/genetics , beta-Lactam Resistance , Cohort Studies , Electrophoresis, Gel, Pulsed-Field , Genotype , Hospitals, University , Intensive Care Units , Molecular Typing , Phenotype , Prospective Studies , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/genetics , beta-Lactamases/genetics
8.
Braz. j. infect. dis ; 18(6): 678-680, Nov-Dec/2014.
Article in English | LILACS | ID: lil-730427

ABSTRACT

Nosocomial infections caused by carbapenem-resistant Acinetobacter baumannii isolates have reached epidemic levels in past decades. Currently this microorganism is responsible for outbreaks of difficult eradication and with high mortality rates worldwide. We herein report a rare case of an OXA-72-producing A. baumannii isolate colonizing a 47-year-old male patient with peritonitis due to abdominal stab wound, four years earlier than the first report of this carbapenemase in Acinetobacter pittii in Colombia. Although OXA-72 presents a low prevalence compared with OXA-23, our study demonstrated that A. baumannii isolates carrying the blaOXA-72 gene were present in the hospital environment in Colombia and could act as a reservoir for further spread to other Acinetobacter species, like A. pittii, causing carbapenem-resistance.


Subject(s)
Humans , Male , Middle Aged , Acinetobacter Infections/microbiology , Acinetobacter baumannii/isolation & purification , Bacterial Proteins/biosynthesis , beta-Lactamases/biosynthesis , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/enzymology , Colombia , Microbial Sensitivity Tests , Molecular Typing
9.
Biomédica (Bogotá) ; 34(supl.1): 91-100, abr. 2014. graf, mapas, tab
Article in Spanish | LILACS | ID: lil-712425

ABSTRACT

Introducción. La evolución de la resistencia bacteriana constituye una amenaza para la salud pública mundial. Los sistemas de vigilancia epidemiológica han integrado técnicas de biología molecular para mejorar las estrategias de control. Objetivo. Describir los perfiles moleculares y fenotípicos de los bacilos Gram negativos en unidades de cuidados intensivos de 23 hospitales de Colombia entre 2009 y 2012. Materiales y métodos. Se diseñó un estudio descriptivo en 23 hospitales del Grupo para el Estudio de la Resistencia Nosocomial (sic.) en Colombia. Se analizaron 38.048 aislamientos usando WHONET durante el periodo descrito. Se describieron perfiles de resistencia para Escherichia coli , Klebsiella pneumoniae , Pseudomonas aeruginosa y Acinetobacter baumannii. En 1.248 cepas se realizó reacción en cadena de la polimerasa (PCR) para detectar las carbapenemasas clínicamente más relevantes. Resultados. Escherichia coli fue el microorganismo más frecuente (promedio=14,8 %); la frecuencia de aislamientos de K. pneumoniae aumentó de 11 % en 2009 a 15 % en 2012 (p<0,001). La tendencia de los perfiles de multirresistencia aumentó en todas las especies estudiadas. De los aislamientos de K. pneumoniae evaluados, 68,4 % fue positivo para KPC ( Klebsiella pneumoniae Carbapenemase ), mientras que la VIM ( Verona Integron-encoded Metallo-betalactamase ) en P. aeruginosa se observó en 46,5 %. Conclusiones. Se observó un incremento en la tendencia de los microorganismos hacia la multirresistencia y una amplia distribución de las carbapenemasas. La articulación de la biología molecular con los sistemas de vigilancia permitió integrar el análisis del fenotipo con los mecanismos de resistencia involucrados en las bacterias estudiadas. Este análisis permitirá la elaboración de guías para el uso adecuado de antimicrobianos y contribuirá a la contención de estas bacterias multirresistentes en Colombia.


Introduction: The continuous evolution of antimicrobial resistance poses a major threat to public health worldwide. Molecular biology techniques have been integrated to epidemiological surveillance systems to improve the control strategies of this phenomenon. Objective: To describe the phenotypic and molecular profiles of the most important Gram negative bacilli from intensive care units in 23 Colombian hospitals during the study period 2009-2012. Materials and methods: A descriptive study was conducted in 23 hospitals belonging to the Colombian Nosocomial Resistance Study Group. A total of 38.048 bacterial isolates were analyzed using WHONET over a four-year period. The antimicrobial resistant profiles were described for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii . Polymerase chain reaction was performed in 1.248 strains to detect the most clinically relevant carbapenemases. Results: Escherichia coli was the most frequently isolated organism (mean=14.8%). Frequency of K. pneumoniae increased significantly from 11% in 2009 to 15% in 2012 (p<0.001). All screened isolates had rising trends of multidrug-resistant profiles. KPC ( Klebsiella pneumoniae carbapenemase) was detected in 68.4% of K. pneumoniae isolates while VIM (Verona integron-encoded metallo-betalactamase) was present in 46.5% of them. Conclusion: In this study, an increase in the trend of multidrug-resistant organisms and a wide distribution of carbapenemases was observed. The integration of molecular biology to surveillance systems allowed the compilation of this data, which will aid in the construction of guidelines on antimicrobial stewardship for prevention in Colombia.


Subject(s)
Adult , Child , Child, Preschool , Humans , Infant , Infant, Newborn , Drug Resistance, Multiple, Bacterial , Gram-Negative Bacteria/drug effects , Gram-Negative Bacterial Infections/microbiology , Intensive Care Units/statistics & numerical data , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/enzymology , Acinetobacter baumannii/isolation & purification , Bacterial Proteins/genetics , Carbapenems/pharmacology , Colombia/epidemiology , Escherichia coli/drug effects , Escherichia coli/enzymology , Escherichia coli/isolation & purification , Gram-Negative Bacteria/enzymology , Gram-Negative Bacteria/isolation & purification , Gram-Negative Bacterial Infections/epidemiology , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/enzymology , Klebsiella pneumoniae/isolation & purification , Population Surveillance/methods , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/enzymology , Pseudomonas aeruginosa/isolation & purification , beta-Lactamases/genetics
14.
Rev. colomb. biotecnol ; 13(1): 58-65, jul. 2011. graf, ilus
Article in Spanish | LILACS | ID: lil-600574

ABSTRACT

Se describió la capacidad de cinco cepas bacterianas para transformar un carbón de bajo rango (CBR), para ello se evaluaron cepas aisladas de microhábitats con presencia de partículas procedentes de los procesos de almacenamiento y lavado de carbón en la mina El Cerrejón (Colombia). Se realizaron ensayos de solubilización de CBR en medio de cultivo sólido y líquido, además de la decoloración de sustancias húmicas (SH) extraídas del CBR. Todas las bacterias evaluadas presentaron capacidad para biotransformar CBR en medio sólido, esta actividad es mayor cuando el CBR ha sido pretratado con ácido nítrico; en medio líquido se alcanzó una pérdida de peso de CBR hasta del 37% por acción de una cepa de Acinetobacter baumannii, acompañada de la aparición de hasta 8,06 mg/ml-1 de sustancias solubles con absorbancia a 465 nm; los cambios en el pH del medio sugieren que la actividad biotransformadora de CBR está asociada a la liberación de sustancias alcalinas; finalmente, se encontró evidencia para sugerir que las SH presentes en el CBR son transformadas por cometabolismo, posiblemente mediante reacciones de depolimerización, decoloración y repolimerización.


in this study were evaluated five bacterial strains isolated from microhabitats with high content of coal particles generated from storage and washing processes, in "The Cerrejón” open coal mine (Colombia), their ability to biotransform a low rank coal (LRC) was described by testing solubilization on solid and liquid culture medium, as well as bleaching of humic substances (HS) extracted from LRC. All tested bacteria showed ability to biotransform LRC on solid medium, this activity is greater when the LRC has been pretreated with nitric acid; in liquid medium LRC reached 37% of weight loss by Acinetobacter baumannii strain, accompanied by the appearance of up to 6.8 mg/ml-1 of soluble substances with absorbance at 465 nm, changes in culture medium pH suggest that LRC biotransformations activity is associated with alkaline substances release, finally found evidence to suggest that HS contained within LRC are transformed by cometabolism, possibly by depolymerization reactions, bleaching and repolimerization.


Subject(s)
Biotransformation/radiation effects , Biotransformation/physiology , Biotransformation/genetics , Biotransformation/immunology , Acinetobacter baumannii/isolation & purification , Acinetobacter baumannii/radiation effects , Acinetobacter baumannii/enzymology , Acinetobacter baumannii/physiology , Acinetobacter baumannii/chemistry
15.
Rev. colomb. biotecnol ; 13(1): 110-114, jul. 2011.
Article in Spanish | LILACS | ID: lil-600581

ABSTRACT

The 16S-23S rRNA gene intergenic spacer (ITS) was analysed by RFLP in this study to identify A. baumannii from 139 isolates from four hospitals (identified as A, B, C and D). One hundred and twenty of these isolates (86.3%) belonged to the A. baumannii species; those identified as being A. baumannii were found to be polyclonal (19 clone groups) when determining the genetic relationships, 16 of them being found in hospital C. Hospitals A, B and D shared two clone groups isolated during different years. This study describes a rapid and easy method for genospecies identification of Acinetobacter baumannii.


Con el objeto de identificar la genomoespecie Acinetobacter baumannii, se estudiaron 189 aislamientos pertenecientes al Complejo Acinetobacter baumannii-Acinetobacter calcoaceticus provenientes de cuatro hospitales colombianos (denominados A,B,C,D) mediante el análisis por RFLP-PCR de la región intergénica espaciador (ITS) de los genes 16S y 23S rRNA. Se encontraron 120 aislamientos (86.3%) pertenecientes a la especie A. baumannii. La estructura de la población fue policlonal, con 19 grupos clonales, 16 de los cuales se hallaron en el hospital C. En los hospitales A,B y D se encontraron 2 grupos clonales aislados durante diferentes años. En este estudio se propone un método rápido y fácil para la identificación de Acinetobacter baumannii.


Subject(s)
Acinetobacter baumannii/isolation & purification , Acinetobacter baumannii/enzymology , Acinetobacter baumannii/physiology , Acinetobacter baumannii/genetics , Acinetobacter baumannii/immunology , Acinetobacter baumannii/metabolism , Acinetobacter baumannii/pathogenicity , Acinetobacter baumannii/chemistry
16.
Indian J Med Microbiol ; 2011 Jul-Sept; 29(3): 302-304
Article in English | IMSEAR | ID: sea-143839

ABSTRACT

This study aims in identifying MBLs particularly Zn requiring Molecular Class B enzymes produced by Pseudomonas aeruginosa and Acinetobacter baumannii .The resistance by these organisms are in a rise against all antibiotics including carbapenems and no prescribed CLSI guidelines is available for detecting them. Clinical isolates antibiotic susceptibility was determined by number of phenotypic tests by addition of 50mM of 10 μl zinc as cofactor for metallo beta lactamase production along with 0.5M ETDA of 5μl (930 μg per disk) plain disks. Increase in zone size of the meropenem -EDTA disk compared to the meropenem disk without EDTA was recorded positive. For Zn requiring MBLs zone towards both disks of EDTA and Zn along with meropenem is detected by DDST.


Subject(s)
Acinetobacter Infections/microbiology , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/enzymology , Acinetobacter baumannii/isolation & purification , Coenzymes/metabolism , Humans , Microbial Sensitivity Tests/methods , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/enzymology , Pseudomonas aeruginosa/isolation & purification , Zinc/metabolism , beta-Lactam Resistance , beta-Lactamases/metabolism
17.
Indian J Med Microbiol ; 2011 Jul-Sept; 29(3): 269-274
Article in English | IMSEAR | ID: sea-143829

ABSTRACT

Objectives: Acinetobacter baumannii is a significant pathogen in health care settings. In recent years, an increase in carbapenem resistance among A. baumannii due to Ambler class B metallo-beta-lactamases or class D OXA carbapenamases has been reported. In this study we detected the presence of OXA carbapenamases and coproduction of metallo-beta-lactamases (blaVIM and blaIMP ) by phenotypic and genotypic methods in carbapenem resistant clinical isolates of Acinetobacter baumannii. Materials and Methods: A total of 116 consecutive, non-duplicate carbapenem resistant A. baumannii isolated from various clinical specimens were included in the study. The modified Hodge test and inhibitor potentiated disk diffusion tests were done for the screening of carbapenamase and metallo-beta-lactamase production, respectively. Polymerase chain reaction (PCR) was performed for the detection of OXA (blaOXA 23 like, blaOXA 24 like, blaOXA-51 like and blaOXA-58 like genes) and metallo-beta-lactamases (blaVIM and blaIMP ) genes. Gene sequencing was performed for representative isolates. Results: Among 116 A. baumannii, OXA genes were detected in 106 isolates. BlaOXA 51 like (n = 99) and blaOXA -23 like (n = 95) were the most common and they coexisted in 89 isolates. blaOXA-24 like gene was detected in two isolates of which one also carried blaOXA-51 like and blaOXA-58 like genes. The modified Hodge test was positive in 113 isolates. The metallo-beta-lactamase screening test was positive in 92 isolates. blavim was detected in 54 isolates of which 1 also carried the blaIMP gene. Conclusions: blaOXA-23 like and bla OXA 51 like genes are the most common types of OXA carbapenamases while the blaVIM type is the most common type of metallo-beta-lactamase contributing to carbapenem resistance in clinical isolates of A. baumannii. The coproduction of OXA and metallo-beta-lactamases is not an uncommon phenomenon in A. baumannii.


Subject(s)
Acinetobacter Infections/microbiology , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/enzymology , Acinetobacter baumannii/isolation & purification , Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Humans , Microbial Sensitivity Tests , Polymerase Chain Reaction , Sequence Analysis, DNA , beta-Lactam Resistance , beta-Lactamases/genetics , beta-Lactamases/metabolism
18.
Mem. Inst. Oswaldo Cruz ; 106(4): 505-506, June 2011.
Article in English | LILACS | ID: lil-592196

ABSTRACT

The aim of the current study was to describe the occurrence of the blaOXA-23 gene and the ISAba1 element in imipenem-susceptible Acinetobacter baumannii strains. By performing the polymerase chain reaction mapping using combinations of ISAba1 forward primers and the blaOXA-23-like gene reverse primers, we demonstrated that the ISAba1 element did not occur upstream of the blaOXA-23 gene in five of 31 isolates, which explained the lack of resistance to imipenem despite the presence of the blaOXA-23 gene. All of the blaOXA-23-positive isolates were susceptible to imipenem and meropenem with minimal inhibitory concentration < 4 µg/mL. Pulsed-field gel electrophoresis analysis revealed four genotypes among the five blaOXA-23-positive isolates. The current report of the blaOXA-23 gene in imipenem-susceptible isolates provided evidence that this gene may be silently spread in a hospital environment and highlighted the threat of undetected reservoirs of carbapenemase genes.


Subject(s)
Humans , Acinetobacter baumannii , Anti-Bacterial Agents , Drug Resistance, Bacterial , Imipenem , beta-Lactamases , Acinetobacter baumannii/enzymology , Acinetobacter baumannii , Disk Diffusion Antimicrobial Tests , Electrophoresis, Gel, Pulsed-Field , Polymerase Chain Reaction
19.
Mem. Inst. Oswaldo Cruz ; 106(3): 368-370, May 2011. tab
Article in English | LILACS | ID: lil-589049

ABSTRACT

Carbapenemase production is an important mechanism of carbapenem resistance among nonfermentative Gram-negative isolates. This study aimed to report the detection of blaOXA-58 gene in multiresistant clinical isolates of Acinetobacter baumannii recovered from inpatients in a public hospital. Polymerase chain reaction tests were performed to detect the blaOXA-23-like, blaOXA-24-like, blaOXA-58-like and blaOXA-51-like genes. The blaOXA-58 and blaOXA-23 genes were detected in one and three isolates, respectively. Sequencing of the blaOXA-58-like amplicon revealed 100 percent identity with the A. baumannii blaOXA-58 gene listed in the GenBank database. This is the first report of an OXA-58-producing A. baumannii isolate in Rio de Janeiro, Brazil.


Subject(s)
Humans , Acinetobacter baumannii , beta-Lactamases , Acinetobacter Infections , Acinetobacter baumannii , Acinetobacter baumannii/enzymology , Anti-Bacterial Agents , Disk Diffusion Antimicrobial Tests , Drug Resistance, Multiple, Bacterial , Polymerase Chain Reaction
20.
J. bras. patol. med. lab ; 45(3): 177-184, jun. 2009. ilus, graf, tab
Article in Portuguese | LILACS | ID: lil-523349

ABSTRACT

INTRODUÇÃO E OBJETIVO: Entre os bacilos Gram-negativos não fermentadores da glicose, Pseudomonas aeruginosa e Acinetobacter baumannii são os agentes etiológicos de infecções hospitalares mais frequentes. A resistência aos carbapenemas entre esses patógenos está se tornando um problema terapêutico mundial e a produção de metalo-beta-lactamases (MBL) tem emergido como um dos mecanismos responsáveis por esta resistência. O presente estudo objetivou verificar a produção de MBL em amostras de P. aeruginosa e A. baumannii isoladas de pacientes internados no Hospital Estadual Azevedo Lima, localizado em Niterói-RJ. MATERIAL E MÉTODOS: Um total de 400 amostras (286 P. aeruginosa e 114 A. baumannii) foi identificado por meio de sistemas comerciais e sua susceptibilidade aos antimicrobianos foi testada por disco-difusão. As amostras resistentes a ceftazidima foram submetidas à avaliação da produção de MBL pelo método de disco-aproximação. RESULTADOS: A produção de MBL foi verificada em 49 amostras de P. aeruginosa (17,1 por cento) e em 20 amostras de A. baumannii (17,5 por cento). Grande parte das amostras de P. aeruginosa e de A. baumannii foi resistente a todos os antimicrobianos testados. CONCLUSÃO: A produção de MBL é um dos mecanismos de resistência aos carbapenemas e outros beta-lactâmicos entre amostras de P. aeruginosa e A. baumannii isoladas no hospital-alvo desta investigação. A rápida detecção deste fenótipo de resistência é essencial para implementar medidas rígidas de controle de infecção e permitir o início de terapia empírica adequada.


INTRODUCTION AND OBJECTIVE: P. aeruginosa and A. baumannii are the most prevalent etiological agents of hospital infections among non-fermentative gram-negative bacilli. Carbapenem resistance among these pathogens has become a therapeutic problem worldwide. Metallo-beta-lactamases (MBL) production has emerged as one of the mechanisms responsible for this resistance. The aim of the present study was to assess MBL production in clinical isolates of P. aeruginosa and A. baumannii from inpatients at Hospital Estadual Azevedo Lima, Niterói, RJ. MATERIAL AND METHODS: A total of 400 strains of P. aeruginosa (286) and A. baumannii (114) were identified through commercial systems. Antimicrobial susceptibility was tested by disk diffusion. Isolates resistant to ceftazidime were screened for MBL production by disk approximation test. RESULTS: MBL production was detected in 49 (17.1 percent) P. aeruginosa isolates and in 20 (17.5 percent) A. baumannii isolates. Most P. aeruginosa and A. baumannii samples were resistant to all antimicrobial agents. CONCLUSION: Production of MBL is one of the mechanisms of carbapenem resistance and other beta-lactams among P. aeruginosa and A. baumannii isolates in the investigated hospital. The rapid detection of this resistance phenotype is essential to implement strict infection control procedures and initiate appropriate empirical therapy.


Subject(s)
Humans , Acinetobacter baumannii , Acinetobacter baumannii/enzymology , Drug Resistance, Multiple, Bacterial , Pseudomonas aeruginosa , Pseudomonas aeruginosa/enzymology , beta-Lactamases/metabolism , Acinetobacter baumannii/isolation & purification , Acinetobacter Infections/drug therapy , Pseudomonas Infections/drug therapy , Microbial Sensitivity Tests , Pseudomonas aeruginosa/isolation & purification
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