Co-Occurrence of Two Plasmids Encoding Transferable blaNDM-1 and tet(Y) Genes in Carbapenem-Resistant Acinetobacter bereziniae.

Acinetobacter bereziniae has emerged as a significant human pathogen, acquiring multiple antibiotic resistance genes, including carbapenemases. This study focuses on characterizing the plasmids harboring the blaNDM-1 and tet(Y) genes in two carbapenem-resistant A. bereziniae isolates (UCO-553 and UCO-554) obtained in Chile during the COVID-19 pandemic. Methods: Antibiotic susceptibility testing was conducted on UCO-553 and UCO-554. Both isolates underwent whole-genome sequencing to ascertain their sequence type (ST), core genome multilocus sequence-typing (cgMLST) profile, antibiotic resistance genes, plasmids, and mobile genetic elements. Conjugation experiments were performed for both isolates. Results: Both isolates exhibited broad resistance, including resistance to carbapenems, third-generation cephalosporins, fluoroquinolones, tetracycline, cotrimoxazole, and aminoglycosides. Both isolates belong to sequence type STPAS1761, with a difference of 17 out of 2984 alleles. Each isolate carried a 47,274 bp plasmid with blaNDM-1 and aph(3')-VI genes and two highly similar plasmids: a 35,184 bp plasmid with tet(Y), sul2, aph(6)-Id, and aph(3″)-Ib genes, and a 6078 bp plasmid containing the ant(2″)-Ia gene. Quinolone-resistance mutations were identified in the gyrA and parC genes of both isolates. Importantly, blaNDM-1 was located within a Tn125 transposon, and tet(Y) was embedded in a Tn5393 transposon. Conjugation experiments successfully transferred blaNDM-1 and tet(Y) into the A. baumannii ATCC 19606 strain, indicating the potential for horizontal gene transfer. Conclusions: This study highlights the critical role of plasmids in disseminating resistance genes in A. bereziniae and underscores the need for the continued genomic surveillance of this emerging pathogen. The findings emphasize the importance of monitoring A. bereziniae for its potential to cause difficult-to-treat infections and its capacity to spread resistance determinants against clinically significant antibiotics.

An outbreak of severe or lethal infections by a multidrug-resistant Acinetobacter baumannii ST126 strain carrying a plasmid with blaNDM-1 and blaOXA-58 carbapenemases.

Acinetobacter baumannii poses a significant health threat because of its frequent implications in hospital outbreaks and multidrug resistance (MDR). Here, we studied four A. baumannii isolates recovered during a hospital outbreak of severe or fatal cases to elucidate their diversity and factors contributing to their increased virulence and antibiotic resistance. The isolates were identified using MALDI-ToF and characterized using comparative genomics, PCR, and antimicrobial susceptibility tests. They were classified as ST126 and exhibited fewer than five chromosomal single-nucleotide variants and the same extrachromosomal content, indicating that they are a single strain (A. baumannii AB01). A. baumannii AB01 showed an MDR phenotype that could be linked to the carriage of parC and gyrA mutations, efflux transporters, aminoglycoside resistance genes, a class C beta-lactamase, and three carbapenemases, some of which are encoded on a 72 kb plasmid. ST126 is infrequent and has not been reported in Latin America, and our genomic data indicate a plausible origin for A. baumannii AB01 within the Pan Pacific region.

Genetic profile and characterization of antimicrobial resistance in Acinetobacter baumannii post-COVID-19 pandemic: a study in a tertiary hospital in Recife, Brazil.

AIMS: To investigate the genetic profile and characterize antimicrobial resistance, including the main ß-lactam antibiotic resistance genes, in Acinetobacterbaumannii isolates from a tertiary hospital in Recife-PE, Brazil, in the post-COVID-19 pandemic period. METHODS AND RESULTS: Acinetobacter baumannii isolates were collected between 2023 and 2024 from diverse clinical samples. Antimicrobial resistance testing followed standardized protocols, with ß-lactamase-encoding genes detected via PCR and sequencing. Investigation into ISAba1 upstream of blaOXA-carbapenemase and blaADC genes was also conducted. Genetic diversity was assessed through ERIC-PCR. Among the 78 A. baumannii, widespread resistance to multiple antimicrobials was evident. Various acquired ß-lactamase-encoding genes (blaOXA-23,-24,-58,-143, blaVIM, and blaNDM) were detected. Furthermore, this is the first report of blaVIM-2 in A. baumannii isolates harboring either the blaOXA-23-like or the blaOXA-143 gene in Brazil. Molecular typing revealed a high genetic heterogeneity among the isolates, and multi-clonal dissemination. CONCLUSION: The accumulation of genetic resistance determinants underscores the necessity for stringent infection control measures and robust antimicrobial stewardship programs to curb multidrug-resistant strains.

High rates of extensively drug-resistant Acinetobacter baumannii in a Peruvian hospital 2013-2019.

Multidrug-resistant (MDR) Acinetobacter baumannii has become a major concern of hospital care. The objective of the study was to evaluate the evolution of antimicrobial resistance of A. baumannii in a Peruvian hospital from 2013 to 2019. A total of 993 A. baumannii clinical isolates were recovered. Antimicrobial resistance levels were extremely high, except for colistin. Among the remaining antibacterial agents, ampicillin plus sulbactam (AMS) was the most active (71.4% of resistance), with resistance levels to the remaining agents ranging from 75.9% to amikacin to 99.2% to ertapenem. The presence of significant differences was observed in extensively drug-resistant (XDR) A. baumannii according to samples origin. No association was observed between MDR or XDR isolates and seasonality. An impressive rate of XDR A. baumannii isolates was found, including a growing number of only-colistin-susceptible isolates highlighting the urgent need for new therapeutic alternatives.

Genomic Analysis of Carbapenem-Resistant Acinetobacter baumannii Strains Recovered from Chilean Hospitals Reveals Lineages Specific to South America and Multiple Routes for Acquisition of Antibiotic Resistance Genes.

Carbapenem-resistant Acinetobacter baumannii (CRAb) is a public health threat accounting for a significant number of hospital-acquired infections. Despite the importance of this pathogen, there is scarce literature on A. baumannii molecular epidemiology and evolutionary pathways relevant to resistance emergence in South American strains. We analyzed the genomic context of 34 CRAb isolates recovered from clinical samples between 2010 and 2013 from two hospitals in Santiago, Chile, using whole-genome sequencing. Several Institut Pasteur scheme sequence types (STs) were identified among the 34 genomes studied here, including ST1, ST15, ST79, ST162, and ST109. No ST2 (the most widespread sequence type) strain was detected. Chilean isolates were phylogenetically closely related, forming lineages specific to South America (e.g., ST1, ST79, and ST15). The genomic contexts of the resistance genes were diverse: while genes were present in a plasmid in ST15 strains, all genes were chromosomal in ST79 strains. Different variants of a small Rep_3 plasmid played a central role in the acquisition of the oxa58 carbapenem and aacC2 aminoglycoside resistance genes in ST1, ST15, and ST79 strains. The aacC2 gene along with blaTEM were found in a novel transposon named Tn6925 here. Variants of Tn7 were also found to play an important role in the acquisition of the aadA1 and dfrA1 genes. This work draws a detailed picture of the genetic context of antibiotic resistance genes in a set of carbapenem-resistant A. baumannii strains recovered from two Chilean hospitals and reveals a complex evolutionary picture of antibiotic resistance gene acquisition events via multiple routes involving several mobile genetic elements. IMPORTANCE Treating infections caused by carbapenem-resistant A. baumannii (CRAb) has become a global challenge given that CRAb strains are also often resistant to a wide range of antibiotics. Analysis of whole-genome sequence data is now a standard approach for studying the genomic context of antibiotic resistance genes; however, genome sequence data from South American countries are scarce. Here, phylogenetic and genomic analyses of 34 CRAb strains recovered from 2010 to 2013 from two Chilean hospitals revealed a complex picture leading to the generation of resistant lineages specific to South America. From these isolates, we characterized several mobile genetic elements, some of which are described for the first time. The genome sequences and analyses presented here further our understanding of the mechanisms leading to multiple-drug resistance, extensive drug resistance, and pandrug resistance phenotypes in South America. Therefore, this is a significant contribution to elucidating the global molecular epidemiology of CRAb.

Fourier transform infrared spectroscopy as a new tool for surveillance in local stewardship antimicrobial program: a retrospective study in a nosocomial Acinetobacter baumannii outbreak.

The aim of our study is to determine the discriminatory power of the Fourier transform infrared spectroscopy (FTIR), using multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) as molecular typing references. The study included seventeen isolates (OXA-23- and OXA-58-producing Acinetobacter baumannii) previously recovered from clinical specimens during the period May 2010-April 2011. Molecular typing was performed by PFGE and MLST. The specimens were analyzed in quadruplicate using the IR Biotyper (Bruker GmbH, Bremen, Germany). For each isolate, the average of the spectra was used for the analysis of the data. Comparing FTIR data with MLST, the results obtained by IR Biotyper are very consistent with those from MLST, since the software was able to differentiate the three ST assigned to the strains. Comparing FTIR data with PFGE, most results could be confirmed, as IR Biotyper clearly differentiated ST-80 SLV OXA-58-producing A. baumannii (pulsotype 3) from the rest of strains of OXA-58-producing A. baumannii (pulsotypes 1 and 2). All the OXA-23-producing A. baumannii isolates (pulsotype 4) grouped together by FTIR. FTIR proved to be an effective tool to investigate local epidemiology, and can achieve the same typeability and discriminatory power as genome-based methods.

High lethality rate of carbapenem-resistant Acinetobacter baumannii in Intensive Care Units of a Brazilian hospital: An epidemiologic surveillance study.

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a growing threat to public health. METHODS: A 3-year retrospective study was conducted to evaluate the prevalence and lethality of multidrug-resistant (MDR) A. baumannii isolated from Brazilian patients. RESULTS: In this study, 219 Acinetobacter baumannii isolates were identified, of which 70.8% (155/219) were isolated from patients hospitalized in intensive care units. Of these, 57.4% (n = 89/155) were assessed, of which 92.1% (82/89) were carbapenem-resistant, and 49 were classified as infected. The lethality rate was 79.6% (39/49). CONCLUSIONS: We highlight the need of an effective epidemiological surveillance measure to contain the dissemination of CRAB in the hospital environment.

Clonal spread of ArmA- and OXA-23-coproducing Acinetobacter baumannii International Clone 2 in Brazil during the first wave of the COVID-19 pandemic.

Introduction. Carbapenem-resistant Acinetobacter baumannii (CRAB) is the primary pathogen causing hospital-acquired infections. The spread of CRAB is mainly driven by the dissemination of resistant clones, and in Latin America, International Clones IC-1 (also known as clonal complex CC1), IC-4 (CC15) and IC-5 (CC79) are the most prevalent.Gap Statement. There are no documented outbreaks of CRAB International Clone 2 (IC-2) reported in Brazil.Aim. To describe a large outbreak of CRAB caused by the uncommon IC-2 in a Brazilian COVID-19 hospital.Methodology. From May 2020 to May 2021, 224 patients infected or colonized with CRAB were identified in a single hospital; 92 % of them were also infected with SARS-CoV-2. From these patients, 137 isolates were recovered and subjected to antimicrobial susceptibility testing, PCR analysis and molecular typing. Whole-genome sequencing and downstream analysis were carried out on a representative isolate (the first available isolate).Results. In 76 % of the patients, a single OXA-23-producing CRAB IC-2 was identified. All the isolates were susceptible to polymyxin B, but highly resistant (>95 %) to aminoglycosides, fluoroquinolones and beta-lactams. Genomic analysis revealed that the representative isolate also carried the 16S rRNA Methylase ArmA, which was detected for the first time in this species in Brazil.Conclusion. We report the rapid spread of an emerging CRAB clone responsible for causing a large outbreak in a hospital in Brazil, a country with predominance of other CRAB clones. Continuous and prospective surveillance is warranted to evaluate the impact of this clone in Brazilian hospital settings.

Carbapenamase-Producing Acinetobacter baumannii in China, Latin America and the Caribbean.

INTRODUCTION: Carbapenem-resistant Acinetobacter baumannii is a complex health problem, causing difficulties in clinical-therapeutic management worldwide. It is of particular concern in Latin America, the Caribbean and China, where it is an emerging health problem. Carbapenemases produced by these organisms inactivate carbapenem antibiotics. Monitoring circulating genotypes' geographic dispersion contributes to more effective control measures. However, exhaustive studies on carbapenem-resistant A. baumannii are scarce. OBJECTIVES: Study the production of carbapenemases in clinical isolates of A. baumannii resistant to carbapenem antibiotics and the geographic distribution of the sequences circulating in China, Latin America and the Caribbean. DATA ACQUISITION: We followed PRISMA indications. We carried out a systematic search in Pubmed, BVS and CKNI on papers on A. baumannii and carbapenemases published during 2015-2020 in English, Spanish and Chinese, and selected 29 cross-sectional studies that met the search criteria. Studies were evaluated using JBI Critical Appraisal tools, and quantitative data were collated for meta-analysis using the Metaprop library in Stata15. DEVELOPMENT: OXA-type carbapenemases were detected in all studies; among A. baumannii resistant to carbapenem antibiotics, predominant types were OXA-23, OXA-24, OXA-54 and OXA-72; metallobetalactamases were identified less frequently than OXA carbapenemases. Only one clinical isolate producer of Class A carbapenemases (KPC) was identified in Colombia. In total, 41 sequence types were identified; in Latin America and the Caribbean the most common types were: ST79, ST25, ST1 and ST15; in China, the sequences ST195, ST208, ST191, ST368 and ST369 were the most prevalent. ST2 was found in both regions. CONCLUSIONS: The most prevalent carbapenemases and sequence types vary by region, indicating different ancestral strains. Microbiological surveillance, antibiotic use optimization, adequate infection treatment and timely control strategies are essential for carbapenem-resistant A. baumannii prevention and control in geographies such as Latin America, the Caribbean and China where such resistance is an emerging health problem.

Spread of multidrug-resistant Acinetobacter baumannii isolates belonging to IC1 and IC5 major clones in Rondônia state.

In Brazil, carbapenem-resistant A. baumannii (CRAB) is a critical pathogen showing high carbapenem resistance rates. Currently, there is little epidemiological data on A. baumannii isolated in the Northern Brazilian region. Herein, this study aimed to characterize the resistance mechanisms of CRAB isolates recovered from hospitalized patients in the state of Rondônia in 2019. Most of CRAB were considered as extensively drug-resistant, and some of them showed high MICs for minocycline. Only polymyxins showed a satisfactory activity. All isolates carried blaOXA-23 and were included in 14 distinct clusters, with the predominance of clonal group A (29%). The IC1 was the most frequent clonal group, followed by IC5 and IC4. Here, we firstly reported the epidemiological scenario of CRAB in the state of Rondônia, located in the Brazilian Amazon region. The high frequency of CRAB presenting XDR phenotype is of great concern, due to limited therapeutical options, especially in the actual pandemic scenario, in which we observed an overcrowding of ICU beds. Such results are essential to better characterize the epidemiology of CRAB in the entire Brazilian territory.

Emerging species in pediatrics: a case of Acinetobacter johnsonii meningitis.

BACKGROUND: Among the microorganisms corresponding to the genus Acinetobacter, Acinetobacter johnsonii is a species of low epidemiological incidence compared to Acinetobacter baumannii. However, it has a comparable infectious capacity since it can be involved in severe diseases like bacteremia or meningitis. Its habitat is variable, usually found in humid tropical climates (as is the case in Colombia), soil, water, or animal reservoirs. It is still an unknown germ for most health personnel, as there are not many reported cases, and information about its microbiological and epidemiological characteristics is still scarce, making its identification and treatment difficult. CLINICAL CASE: We describe the case of A. johnsonii infection of the central nervous system in a 15-year-old female, as well as the diagnostic method used, the course of the disease, medical management, and clinical outcome. CONCLUSIONS: It is of utmost importance to report this type of microorganisms to facilitate early diagnosis and appropriate treatment. More scientific publications of this type are needed to broaden the knowledge about these microorganisms.

INTRODUCCIÓN: Dentro de los microorganismos correspondientes al género Acinetobacter, Acinetobacter johnsonii es una especie de poca frecuencia epidemiológica en comparación con Acinetobacter baumannii. Sin embargo, posee una capacidad infecciosa equiparable, ya que se puede ver involucrado en patologías graves, como bacteriemia o meningitis. Su hábitat es variable y suele encontrarse en climas tropicales húmedos (como es el caso de Colombia), suelos, aguas o reservorios animales. Actualmente sigue siendo un patógeno desconocido por gran parte del personal de salud, pues no existen muchos casos reportados, y la información acerca de sus características microbiológicas y epidemiológicas aún es escasa, lo que dificulta su identificación y tratamiento. CASO CLÍNICO: Se describe una infección del sistema nervioso central por A. johnsonii en una paciente de sexo femenino de 15 años, así como el método diagnóstico utilizado, el curso de la enfermedad, el manejo médico y el desenlace clínico. CONCLUSIONES: Es de suma importancia dar a conocer la existencia de estos microorganismos para facilitar el diagnóstico temprano y el tratamiento apropiado. Se requieren más publicaciones científicas de este tipo para ampliar el conocimiento acerca de estos microorganismos.

Genomic insights of Acinetobacter baumannii ST374 reveal wide and increasing resistome and virulome.

WGS-based surveillance has significantly improved the ability to track global spread and emergence of multidrug-resistant clones of clinically relevant pathogens. In this study, we performed the genomic characterization and comparative analysis of an Acinetobacter baumannii (strain Ac56) belonging to the sequence type ST374, which was isolated for the first time in Brazil, in 1996. Genomic analysis of Ac56 predicted a total of 5373 genes, with 3012 being identical across nine genomes of A. baumannii isolates of ST374 from European, Asian, North and South American countries. GoeBURST analysis grouped ST374 lineages into clonal complex CC3 (international clone IC-III). Resistome analysis of ST374 clone predicted genes associated with resistance to heavy metals and clinically relevant beta-lactams and aminoglycosides antibiotics. In this regard, in two closely related A. baumannii strains, the intrinsic blaADC gene was linked to the insertion sequence ISAba1; including the Ac56 strain, where it has been possibly associated with intermediate susceptibility to meropenem. Other four carbapenem-resistant A. baumannii strains carried the ISAba1/blaOXA-23 gene array, which was associated with the transposon Tn2008 or with Tn2006 in an AbaR4-type resistance island. While most virulence genes were shared for A. baumannii strains of ST374, three isolates from Thailand harbored KL49 capsular loci, previously identified in the hypervirulent A. baumannii LAC-4 strain. Analysis of thirty-four predicted plasmids showed eight major groups, of which GR-6 (LN-1) and GR-2 (LN-2) were prevalent. All strains, including the earliest isolate Ac56 harbored at least one complete prophage, whereas none CRISPR-associated (cas) gene was detected. In summary, genomic data of A. baumannii ST374 reveal a potential of this lineage to become a successful clone.

Seasonality and weather dependance of Acinetobacter baumannii complex bloodstream infections in different climates in Brazil.

Recent studies report seasonality in healthcare-associated infections, especially those caused by Acinetobacter baumannii complex. We conducted an ecologic study aimed at analyzing the impact of seasons, weather parameters and climate control on the incidence and carbapenem-resistance in A. baumannii complex bloodstream infections (ABBSI) in hospitals from regions with different climates in Brazil. We studied monthly incidence rates (years 2006-2015) of ABBSI from hospitals in cities from different macro-regions in Brazil: Fortaleza (Ceará State, Northeast region), Goiânia (Goiás State, Middle-west) and Botucatu (São Paulo State, Southeast). Box-Jenkins models were fitted to assess seasonality, and the impact of weather parameters was analyzed in Poisson Regression models. Separate analyses were performed for carbapenem-resistant versus carbapenem-susceptible isolates, as well as for infections occurring in climate-controlled intensive care units (ICUs) versus non-climate-controlled wards. Seasonality was identified for ABSSI ICUs in the Hospitals from Botucatu and Goiânia. In the Botucatu hospital, where there was overall seasonality for both resistance groups, as well as for wards without climate control. In that hospital, the overall incidence was associated with higher temperature (incidence rate ratio for each Celsius degree, 1.05; 95% Confidence Interval, 1.01-1.09; P = 0.006). Weather parameters were not associated with ABBSI in the hospitals from Goiânia and Fortaleza. In conclusion, seasonality was found in the hospitals with higher ABBSI incidence and located in regions with greater thermal amplitude. Strict temperature control may be a tool for prevention of A. baumanii infections in healthcare settings.

A four-year follow-up survey of antimicrobial resistance among Acinetobacter baumannii complex from inpatients in Southern Brazil.

OBJECTIVES: To determine the trends of antimicrobial resistance for Acinetobacter baumannii complex isolates recovered from inpatients over a 4-year follow-up survey. METHODS: A total of 659 A baumannii complex isolates were recovered from hospitalized patients in Porto Alegre and its metropolitan area, Southern Brazil, from 2017 to 2020. Susceptibility profile was determined for ampicillin/sulbactam, amikacin, gentamicin, imipenem, meropenem, minocycline, polymyxin B and tigecycline. RESULTS: Overall, PMB was the most active agent against the set of A baumannii isolates over the period. Although stable, a high resistance rate was observed. CONCLUSIONS: Our results shown the presence of an extensively-drug resistant A baumannii complex isolates over the past four years. Polymyxin B has been the only antimicrobial agent that remain with a good in vitro activity. Strict surveillance and infection control measures are mandatory.

Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii from southern Brazil / Epidemiologia molecular de Acinetobacter baumannii resistente aos carbapenêmicos provenientes do sul do Brasil / Epidemiología molecular de Acinetobacter baumannii resistente a carbapenem del sur de Brasil

Background and Objectives: carbapenem resistance in Acinetobacter baumannii has reached extremely high levels worldwide, and class D OXA-type carbapenemases are the main associated mechanism. This study aimed to assess the phenotypic and molecular profile of clinical carbapenem-resistant A. baumannii (CRAb) isolates from a southern Brazilian border region. Methods: A. baumannii species was identified by the presence of the blaOXA-51 gene, and the susceptibility profile was determined by broth microdilution. The main carbapenemases were investigated by PCR and the molecular typing was performed by PFGE. Results: during the study, a total of 36 CRAb were recovered, of which 85.7% were from respiratory tract samples from ICU patients. High level resistance to were found in contrast to 100% of susceptibility for polymyxin B. The blaOXA-23 gene was present in 34 isolates and was the only one detected other than blaOXA-51. Molecular typing revealed the presence of four clonal strains, two of them endemic during the period of the study. Conclusion: to the best of our knowledge, our study brings the first data about resistance profile in Acinetobacter in the western border of southern Brazil and make aware of endemic clones of CRAb-producing-OXA-23 in this region of state, contributing for the construction of the national epidemiologic scenario of CRAb.(AU)

Justificativa e Objetivos: a resistência aos carbapenêmicos em Acinetobacter baumannii atingiu níveis extremamente altos em todo o mundo, e as carbapenemases do tipo OXA classe D são o principal mecanismo associado. O objetivo deste estudo foi avaliar o perfil fenotípico e molecular de isolados clínicos de A. baumannii resistentes aos carbapenêmicos (CRAb) de uma região de fronteira do sul do Brasil. Métodos: a espécie A. baumannii foi identificada através da presença do gene blaOXA-51, e o perfil de sensibilidade foi determinado por microdiluição em caldo. As principais carbapenemases foram investigadas por PCR, e a tipagem dos isolados de CRAb foi realizada por PFGE. Resultados: durante o período do estudo, 36 CRAb foram recuperados, dos quais 85,7% foram provenientes de amostras do trato respiratório de pacientes de UTI. Uma elevada resistência a aminoglicosídeos e fluoroquinolonas foi encontrada em contraste com 100% de sensibilidade a polimixina B. O gene blaOXA-23 foi encontrado em 34 isolados e foi o único detectado além do blaOXA-51. A tipagem molecular revelou a presença de quatro linhagens clonais, duas delas endêmicas ao longo do período do estudo. Conclusão: nosso estudo traz os primeiros dados sobre o perfil de resistência em Acinetobacter na fronteira oeste do sul do Brasil e alerta para a presença de clones endêmicos de CRAb produtores de OXA-23 nessa região, contribuindo para a construção do cenário epidemiológico nacional de CRAb.(AU)

Justificación y Objetivos: la resistencia a carbapenémicos en Acinetobacter baumannii ha alcanzado niveles extremadamente altos en todo el mundo y las carbapenemases OXA de clase D son el principal mecanismo asociado. El objetivo de este estudio fue evaluar el perfil fenotípico y molecular de los aislados clínicos de A. baumannii resistentes a carbapenémicos (CRAb) de una región fronteriza en el sur de Brasil. Métodos: la especie A. baumannii se identificó a través de la presencia del gen blaOXA-51 y el perfil de sensibilidad se determinó por microdilución en caldo. Las principales carbapenemasas fueron investigadas por PCR y la tipificación se hizo con PFGE. Resultados: durante el período de estudio, se recuperaron 36 CRAb, 85,7% de muestras del tracto respiratorio de pacientes de la UCI. Se encontró una alta resistencia a los aminoglucósidos y las fluoroquinolonas en contraste con 100% de sensibilidad a polimixina B. El gen blaOXA-23 se encontró en 34 aislamientos y fue el único detectado además de blaOXA-51. La tipificación molecular reveló la presencia de cuatro cepas clonales, dos de ellas endémicas durante el período de estudio. Conclusiones: hasta donde sabemos, nuestro estudio trae los primeros datos sobre el perfil de resistencia en Acinetobacter en la frontera oeste del sur de Brasil y reconoce los clones endémicos de CRAb productores de OXA.(AU)

Associated factors of Acinetobacter baumannii complex in hospitalized patients: A case-control study.

INTRODUCTION: Acinetobacter baumannii complex are microorganisms of critical priority of resistance, being associated with higher costs and negative outcomes for hospitalized patients. Thus, the study aimed to analyse the factors associated with A. baumannii complex infection in various hospital sectors. METHODOLOGY: This is a case-control study that included patients hospitalized from January 2017 to June 2019. Demographic, microbiological and clinical variables were collected from each patient. All cases had positive culture results for A. baumannii complex resistant to more than three classes of antimicrobials. Carbapenem-resistance was examined by the disk diffusion test, while the broth microdilution method was used to determine the susceptibility to colistin. RESULTS: A. baumannii complex infection was mostly present in ICU (74.2%) than in other hospital areas. The bacteria was also linked with the length of hospitalization until the results for the culture (OR = 1.13; 95% CI: 1.06 - 1.21; p < 0.001) and with pneumonia associated with mechanical ventilation (OR = 4.48; 95% CI: 1.55 - 13.00; p = 0.006). Moreover, patients exposed to infection with multidrug-resistant A. baumannii complex had higher risks of death (OR = 3.25; 95% CI: 1.06 - 9.91; p = 0.039). CONCLUSIONS: This study provides evidence that A. baumannii complex infection is associated with the number of days of hospitalization up to culture positivity, pneumonia associated with the use of mechanical ventilation and death. Infections appear to be more critical in ICU when compared to other areas. Taken together, these findings could support hospital infection surveillance programs, as well as prevention measures to reduce mortality rates and other complications.

Silent mutations in ribosomal protein genes are associated with high-risk clones of carbapenem-resistant Acinetobacter baumannii prevalent in Brazil.

OBJECTIVES: To analyze the relationship of ribosomal protein mutations and clonality of high-risk clones Acinetobacter baumannii. METHODS: Seventy-nine carbapenem-resistant A. baumannii were subjected to whole-genome sequencing (Illumina NextSeq), and codifying sequences of ribosomal proteins were extracted and screened for mutations. MALDI-TOF MS analysis (Bruker Biotyper) and Spectra data from MALDI-TOF was employed to generate a dendrogram based on principal component analysis (PCA) data. Clones were identified by Multilocus sequencing typing (MLST) based on WGS. RESULTS: Ribosomal RNA protein sequences extracted from the genomes identified mutations that were associated with clonal complexes, but most of them were silent. PCA did not cluster the isolates according to their clonality identified by MLST. CONCLUSIONS: By comparing the nucleotide and amino acid sequences of diversified A. baumannii, and Bruker Biotyper profiles, we showed that silent mutations in ribosomal RNA nucleotides are associated with clonal complexes, but since most of the mutations were silent, MALDI-TOF MS raw data was not a useful tool for typing the high-risk clones of this species.

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.