Comparative microbiome analysis in cystic fibrosis and non-cystic fibrosis bronchiectasis.

BACKGROUND: Bronchiectasis is a condition characterized by abnormal and irreversible bronchial dilation resulting from lung tissue damage and can be categorized into two main groups: cystic fibrosis (CF) and non-CF bronchiectasis (NCFB). Both diseases are marked by recurrent infections, inflammatory exacerbations, and lung damage. Given that infections are the primary drivers of disease progression, characterization of the respiratory microbiome can shed light on compositional alterations and susceptibility to antimicrobial drugs in these cases compared to healthy individuals. METHODS: To assess the microbiota in the two studied diseases, 35 subjects were recruited, comprising 10 NCFB and 13 CF patients and 12 healthy individuals. Nasopharyngeal swabs and induced sputum were collected, and total DNA was extracted. The DNA was then sequenced by the shotgun method and evaluated using the SqueezeMeta pipeline and R. RESULTS: We observed reduced species diversity in both disease cohorts, along with distinct microbial compositions and profiles of antimicrobial resistance genes, compared to healthy individuals. The nasopharynx exhibited a consistent microbiota composition across all cohorts. Enrichment of members of the Burkholderiaceae family and an increased Firmicutes/Bacteroidetes ratio in the CF cohort emerged as key distinguishing factors compared to NCFB group. Staphylococcus aureus and Prevotella shahii also presented differential abundance in the CF and NCFB cohorts, respectively, in the lower respiratory tract. Considering antimicrobial resistance, a high number of genes related to antibiotic efflux were detected in both disease groups, which correlated with the patient's clinical data. CONCLUSIONS: Bronchiectasis is associated with reduced microbial diversity and a shift in microbial and resistome composition compared to healthy subjects. Despite some similarities, CF and NCFB present significant differences in microbiome composition and antimicrobial resistance profiles, suggesting the need for customized management strategies for each disease.

Evaluation of the ceftazidime/avibactam and meropenem susceptibility by MALDI-TOF MS directly from positive blood cultures.

The purpose of this study was to evaluate the MBT-ASTRA to determine susceptibility to ceftazidime/avibactam (CZA) and meropenem (MEM) of Enterobacterales directly from positive blood cultures (BC). Bacterial suspension was incubated with antibiotic and analyzed by MALDI-TOF MS. The relative growth was calculated and cutoff values were determined to categorize isolates as "S," "I," and "R." Klebsiella spp. with CZA 20/8 mg/L and 1.5-h incubation presented 1 (5.9%) major discrepancy and 96.3% category agreement; other species required 2.5 h for 100% category agreement. For MEM, 4 mg/L and 1.5h were necessary, demonstrating 2 (6.67%) minor discrepancies and 93.3% categorical agreement.

Rapid colorimetric polymyxin B microelution directly from positive blood bottles: because patients with serious infections should not have to wait for results of culture-based methodologies.

PURPOSE: To evaluate the performance of the rapid colorimetric polymyxin B microelution (RCPEm) in determining polymyxin B resistance directly from Enterobacterales-positive blood cultures. METHODS: A set volume of positive blood culture bottles (diluted 1:10) was inoculated into a glucose-broth-phenol red solution (NP solution), where a polymyxin B disk was previously eluted (final concentration of 3 µg/mL). Test was read each 1 h for up to 4 h. Color change from red/orange to yellow indicated resistant isolates. Results were compared to the reference method, broth microdilution (BMD), performed from colonies grown on solid media from the same blood culture bottle. RESULTS: One hundred fifty-two Enterobacterales-positive blood cultures were evaluated, 22.4% (34/152) of them resistant to polymyxin B (including 6.6% with borderline MICs). When performing directly from positive blood cultures (RCPEm-BC), specificity and sensitivity were 99.1% and 94.1%, respectively. Of note, 79.4% (27/34) of truly resistant isolates required 3 h of incubation, compared to the 18 ± 2 h incubation that microtiter plates of BMD demand before reading can be performed. CONCLUSIONS: RCPEm directly from blood cultures has great potential to be part of the routine of clinical microbiology laboratories to establish polymyxin B susceptibility, impacting outcome of patients with bloodstream infections caused by carbapenem-resistant Enterobacterales.

Detection of polymyxins resistance among Enterobacterales: evaluation of available methods and proposal of a new rapid and feasible methodology.

BACKGROUND: Fast and accurate detection of polymyxins resistance is necessary as they remain the last resources to treat infections caused by Carbapenem-resistant Enterobacterales in many regions. We evaluated the rapid colorimetric polymyxin B elution (RCPE) and developed its miniaturized version, RCPE microelution (RCPEm), aiming to detect polymyxins resistance among Enterobacterales. METHODS: The methodologies consist of exposing the bacterial population in a solution (NP solution) where polymyxin B disks were previously eluted to obtain a concentration of 2 µg/mL for RCPE and 3 µg/mL for RCPEm. RESULTS: Two hundred sixty-seven Enterobacterales were evaluated, 90 (33.7%) resistant to polymyxin B by broth microdilution. It was observed 0.6% of major error (ME) by RCPE, with a specificity of 99.4%. The miniaturized version (RCPEm) presented the same ME and specificity values, but slightly higher sensitivity (97.8% vs. 95.6%) with 2.2% of very major error (VME). CONCLUSIONS: RCPE and RCPEm proved to be useful alternatives to determine polymyxin B susceptibility in clinical microbiology laboratories, presenting low cost, being easy to perform, and demanding short incubation time.

Gut microbiota modulation by prednisolone in a rat kindling model of pentylenetetrazol (PTZ)-induced seizure.

The gut microbiota is a complex community composed by several microorganisms that interact in the maintenance of homeostasis and contribute to physiological processes, including brain function. The relationship of the taxonomic composition of the gut microbiota with neurological diseases such as autism, Parkinson's, Alzheimer's, anxiety, and depression is widely recognized. The immune system is an important intermediary between the gut microbiota and the central nervous system, being one of the communication routes of the gut-brain axis. Although the complexity of the relationship between inflammation and epilepsy has not yet been elucidated, inflammatory processes are similar in many ways to the consequences of dysbiosis and contribute to disease progression. This study aimed to analyze the taxonomic composition of the gut microbiota of rats treated with prednisolone in a kindling model of epilepsy. Male Wistar rats (90 days, n = 24) divided into four experimental groups: sodium chloride solution 0.9 g%, diazepam 2 mg/kg, prednisolone 1 mg/kg, and prednisolone 5 mg/kg administered intraperitoneally (i.p.) for 14 days. The kindling model was induced by pentylenetetrazole (PTZ) 25 mg/kg i.p. on alternate days. The taxonomic profile was established by applying metagenomic DNA sequencing. There was no change in alpha diversity, and the composition of the gut microbiota between prednisolone and diazepam was similar. The significant increase in Verrucomicrobia, Saccharibacteria, and Actinobacteria may be related to the protective activity against seizures and inflammatory processes that cause some cases of epilepsy. Further studies are needed to investigate the functional influence that these species have on epilepsy and the inflammatory processes that trigger it.

Pooling of samples to optimize SARS-CoV-2 diagnosis by RT-qPCR: comparative analysis of two protocols.

This study has aimed to evaluate the use pool of samples as a strategy to optimize the diagnostic of SARS-CoV-2 by RT-qPCR. A total of 220 naso/orofaryngeal swab samples were collected and tested using two different protocols of sample pooling. Results from protocol A were identical with the individual results. However, for results from protocol B, reduced agreement (91%) was observed in relation to individual testing. Inconsistencies observed were related to RT-qPCR results with higher cycle thresholds. These results suggest that pooling of samples before RNA extraction is preferable in terms of diagnostic for SARS-CoV-2.

Detection of SARS-CoV-2 lineage P.1 in patients from a region with exponentially increasing hospitalisation rate, February 2021, Rio Grande do Sul, Southern Brazil.

The emergence of SARS-CoV-2 P.1 lineage coincided with a surge in hospitalisations in the North region of Brazil. In the South region's Rio Grande do Sul state, severe COVID-19 case numbers rose 3.8 fold in February 2021. During that month, at a COVID-19 referral hospital in this state, whole-genome sequencing of a subset of cases' specimens (n = 27) revealed P.1 lineage SARS-CoV-2 in most (n = 24). Findings raise concerns regarding a possible association between lineage P.1 and rapid case and hospitalisation increases.

Hepatoprotective Effect of Probiotic Lactobacillus rhamnosus GG Through the Modulation of Gut Permeability and Inflammasomes in a Model of Alcoholic Liver Disease in Zebrafish.

Objective: Alcoholic liver disease (ALD) is among the leading causes of death from liver disease. Among the factors involved in its pathogenesis are inflammation and increased intestinal permeability. The aim of this study was to assess the effect of Lactobacillus rhamnosus GG (LGG) on hepatic lipid accumulation, activation of inflammasomes, and gut permeability markers in experimental model of ALD with zebrafish.Methods: An experiment was conducted to assess the effective LGG dose capable of promoting intestinal colonization. Animals were divided into three groups (n = 64/group): ethanol group (E), ethanol + probiotic group (EP), and control group (C). Groups E and EP were exposed to 0.5% ethanol concentration for 28 days. At the end of this period, animals were euthanized, and livers were collected for Oil Red staining and assessment of the inflammasome system. Intestines were collected for evaluation of gut permeability markers.Results: The dose of 1.55 × 106 UFC LGG/fish/d promoted intestinal colonization. Group EP presented lower hepatic lipid accumulation, lower il-1ß expression, and higher cldn15a expression when compared to group E.Conclusions: Supplementation with LGG was protective for hepatic steatosis in ALD model. In addition, LGG influenced the modulation of the inflammatory response and markers of gut permeability, improving the gut barrier structure.

Salmonella enterica mcr-1 Positive from Food in Brazil: Detection and Characterization.

The mcr-1 gene has been identified in bacterial isolates obtained from humans, animals, environment, and food, including Salmonella spp., which is one of the major foodborne pathogens worldwide. The aim of this study was to evaluate the presence of mcr-1 gene in Salmonella spp. from food produced in Brazil and to characterize the isolates harboring this gene. A total of 490 Salmonella spp. isolates from the Brazilian National Program for the Control of Foodborne Pathogens were screened for the presence of mcr-1 gene by polymerase chain reaction (PCR). Whole genome sequencing (WGS) was performed in positive isolates to characterize the sequence type (ST), plasmid families and resistance genes. Antimicrobial susceptibility tests were performed by broth microdilution. Selected isolates were submitted to conjugation experiments using the Escherichia coli J53 as a receptor. We detected eight isolates harboring the mcr-1 gene; seven belonged to Salmonella enterica serovar Typhimurium and its monophasic variant 4,[5],12:i:-, and one belonged to serovar Saintpaul. Seven of the mcr-1 positive isolates displayed a high rate of resistance to other antibiotics in addition to colistin. Analysis of the WGS indicated that the ST 19 was the most common ST among the mcr-1 positive isolates. The mcr-1 gene was located in an IncX4 plasmid of ∼33 kb, with no additional resistance genes and with high identity with a plasmid obtained from a clinical isolate of E. coli mcr-1 positive in Brazil. All plasmids harboring the mcr-1 gene were able to conjugate. Our results suggest the spread of a single plasmid type in Brazil harboring the mcr-1 among Salmonella spp. The horizontal transfer of this mobile element has been contributing to the spread of the colistin resistance in the country.

Rapid Detection of Carbapenemase Production Directly from Blood Culture by Colorimetric Methods: Evaluation in a Routine Microbiology Laboratory.

The aim of this study was to evaluate the two rapid colorimetric methods (CNPt-Direct and Blue-Carba) for the detection of carbapenemase production directly from blood culture in a routine microbiology laboratory. The methods were initially evaluated on spiked blood cultures with 61 carbapenemase-positive isolates. Afterwards, they were used in blood cultures (314 samples were evaluated) obtained from patients in a routine microbiology laboratory during a period of 6 months. The colorimetric methods were compared to the conventional culture of blood. The results of the spiked blood cultures indicated that both colorimetric methods presented positive results for the vast majority (95%) of the isolates harboring KPC, NDM, and IMP genes. However, the assay failed to detect many GES- and OXA-48-like-positive isolates (65% positive results). In the second part of the study, a total of 314 blood cultures from patients were evaluated, and 33 yielded Enterobacteriaceae isolates resistant to meropenem (30 isolates were positive for carbapenemases according to PCR). The colorimetric tests correctly detected 24 out of the 30 carbapenemase-positive isolates directly from the blood vial (80% positive results). Overall positive percent agreement and negative percent agreement were 80% and 100%, respectively. The colorimetric assays are simple and cost-effective methods that can be implemented in a routine microbiology laboratory, diminishing the time necessary to detect carbapenemase-producing isolates from 24 to 48 h to 3 to 5 h. Moreover, according to our results, the positive colorimetric test results do not need to be confirmed and can be immediately provided to the attending physician.

Genetic Background of ß-Lactamases in Enterobacteriaceae Isolates from Environmental Samples.

The prevalence of ß-lactamase-producing Enterobacteriaceae has increased worldwide. Although antibiotic-resistant bacteria are usually associated with hospitals, there are a growing number of reports of resistant bacteria in other environments. Concern about resistant microorganisms outside the hospital setting highlights the need to investigate mechanisms of antibiotic resistance in isolates collected from the environment. The present study evaluated the resistance mechanism to ß-lactam antibiotics in 40 isolates from hospital sewage and surface water from the Dilúvio Stream, Porto Alegre City, Southern Brazil. The multiplex PCR technique was used to detect several resistance genes of ß-lactamases: extended-spectrum ß-lactamases (ESBLs), carbapenemases, and ß-lactamase AmpC. After genes, detection amplicons were sequenced to confirm their identification. The clonal relationship was established by DNA macrorestriction using the XbaI enzyme, followed by pulsed-field gel electrophoresis (PFGE). The results indicated that resistance genes were present in 85% of the isolates. The most prevalent genes encoded narrow-spectrum ß-lactamase, such as TEM-1 and SHV-1 with 70% of the strains, followed by carbapenemase KPC and GES (45%), ESBL types SHV-5 and CTX-M-8 (27.5%), and AmpC (ACT-1/MIR-1) (2.5%). Twelve isolates contained only one resistance gene, 14 contained two, and eight isolates had three resistance genes. PFGE indicated a clonal relationship among K. pneumoniae isolates. It was not possible to establish a clonal relationship between Enterobacter sp. isolates. The results highlight the potential of these resistance genes to spread in the polluted environment and to present a health risk to communities. This report is the first description of these resistance genes present in environmental samples other than a hospital in the city of Porto Alegre/RS.

Lack of association between rrl and erm(41) mutations and clarithromycin resistance in Mycobacterium abscessus complex.

BACKGROUND: Mycobacterium abscessus complex (MABC) includes species with high resistance rates among mycobacterial pathogens. In fact, MABC infections may not respond to clarithromycin treatment, which has historically been very effective against MABC infection. Molecular markers have been proposed to detect both acquired (rrl polymorphisms) and inducible (erm(41) polymorphisms) clarithromycin resistance in MABC isolates. OBJECTIVES: This study aimed to evaluate the susceptibility profile and molecular markers of clarithromycin resistance in MABC. METHODS: The clarithromycin susceptibility profile was determined by broth microdilution with reads on days 3, 5, 7 and 14. Mutations in the rrl and erm(41) genes were evaluated by polymerase chain reaction (PCR) using specific primers, followed by sequencing. FINDINGS: A total of 14 M. abscessus subsp. abscessus isolates and 28 M. abscessus subsp. massiliense isolates were evaluated, and clarithromycin resistance was observed in all isolates for up to three days of incubation. None of the 42 isolates exhibited a point mutation in the rrl gene, while all the isolates had a T28 polymorphism in the erm(41) gene. Moreover, all 28 M. abscessus subsp. massiliense isolates had a deletion in the erm(41) gene. MAIN CONCLUSIONS: While all the MABC isolates exhibited acquired clarithromycin resistance, no isolates exhibited a point mutation in the rrl gene in this study. The M. abscessus subsp. massiliense isolates demonstrated clarithromycin resistance, which is an uncommon phenotype. The molecular data for the rrl and erm(41) genes were not consistent with the phenotypic test results of clarithromycin susceptibility, indicating a lack of correlation between molecular clarithromycin resistance markers for both acquired and inducible resistance.

Characterization of Tn3000, a Transposon Responsible for blaNDM-1 Dissemination among Enterobacteriaceae in Brazil, Nepal, Morocco, and India.

In Enterobacteriaceae, the blaNDM genes have been found in many different genetic contexts, and a wide diversity of plasmid scaffolds bearing those genes has been found. In August 2013, we identified NDM-1-producing Escherichia coli and Enterobacter hormaechei strains from a single rectal swab sample from a patient hospitalized in Rio de Janeiro, Brazil, who had no history of travel abroad. Complete DNA sequencing using the Illumina platform and annotation of the two plasmids harboring the blaNDM-1 gene, one from each strain, showed that they belonged to incompatibility groups IncFIIK and IncX3 and harbored a novel transposon named Tn3000. Similar genetic structures have been identified among other isolates in Brazil but also on plasmids from other continents. Our findings suggest that the blaNDM-1 gene may be transmitted by Tn3000 in different parts of the world.

Evaluation of respiratory syncytial virus group A and B genotypes among nosocomial and community-acquired pediatric infections in Southern Brazil.

BACKGROUND: Respiratory syncytial virus (RSV) is the main cause of lower respiratory tract illness in children worldwide. Molecular analyses show two distinct RSV groups (A and B) that comprise different genotypes. This variability contributes to the capacity of RSV to cause yearly outbreaks. These RSV genotypes circulate within the community and within hospital wards. RSV is currently the leading cause of nosocomial respiratory tract infections in pediatric populations. The aim of this study was to evaluate the G protein gene diversity of RSV amplicons. METHODS: Nasopharyngeal aspirate samples were collected from children with nosocomial or community-acquired infections. Sixty-three RSV samples (21 nosocomial and 42 community-acquired) were evaluated and classified as RSV-A or RSV-B by real-time PCR. Sequencing of the second variable region of the G protein gene was performed to establish RSV phylogenetics. RESULTS: We observed co-circulation of RSV-A and RSV-B, with RSV-A as the predominant group. All nosocomial and community-acquired RSV-A samples were from the same phylogenetic group, comprising the NA1 genotype, and all RSV-B samples (nosocomial and community-acquired) were of the BA4 genotype. Therefore, in both RSV groups (nosocomial and community-acquired), the isolates belonged to only one genotype in circulation. CONCLUSIONS: This is the first study to describe circulation of the NA1 RSV genotype in Brazil. Furthermore, this study showed that the BA4 genotype remains in circulation. Deciphering worldwide RSV genetic variability will aid vaccine design and development.

Detection of Carbapenem Resistance in Enterobacterales Directly From Positive Blood Cultures Using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry.

CONTEXT.­: Carbapenem-resistant Enterobacterales are disseminated worldwide and associated with infections with high rates of morbidity and mortality. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a useful tool for identification of pathogens directly from blood cultures in clinical microbiology laboratories. Furthermore, it has been applied for the detection of carbapenemase production, by evaluating carbapenem hydrolysis. OBJECTIVE.­: To determine meropenem hydrolysis to detect carbapenemase production directly from positive blood cultures, using logRQ to establish a quantitative measure of hydrolysis. DESIGN.­: We evaluated 100 Enterobacterales from positive blood cultures, with 81 carrying a carbapenemase gene (blaKPC, blaGES, blaNDM-1, blaIMP, blaVIM, and blaOXA-48-like), as determined by real-time multiplex polymerase chain reaction with high-resolution melting (HRM-qPCR). Bacterial proteins extracted from positive blood culture bottles were incubated in a meropenem solution (2-4 hours) followed by centrifugation for MALDI-TOF MS analysis. The intensity of peaks of the hydrolyzed and nonhydrolyzed forms were used to calculate the logRQ value. RESULTS.­: Overall, sensitivity was 86.8% and specificity, 89.5%. Of note, sensitivity varied depending on enzyme type. For blaKPC-positive isolates, sensitivity was 97.9%, while it reduced significantly for blaNDM-1 and blaOXA-48-like isolates: 62.5% (10 of 16) and 66.7% (6 of 9), respectively. Indeed, logRQ was higher in blaKPC-positive isolates (0.37-1.97) than in blaNDM-1 (-1.37 to 0.83) and blaOXA-48-like isolates (-1.08 to 1.79). CONCLUSIONS.­: This is an inexpensive and rapid test to identify carbapenemase activity directly from blood culture bottles, which contributes to early adequate antimicrobial therapy and implementation of infection control measures.

Determination of aztreonam/ceftazidime-avibactam synergism and proposal of a new methodology for the evaluation of susceptibility in vitro.

We proposed a new methodology, the microelution ATM/CZA (mATM/CZA), based on the antibiotic disc elution and the use of resazurin, for rapid (<4h) determination of in vitro susceptibility to aztreonam combined with ceftazidime-avibactam among Enterobacterales. The mATM/CZA presented excellent accuracy with 1.9 %, 98.1 % and 100 % of major error, specificity and sensitivity, respectively. Furthermore, we assessed synergism between aztreonam and ceftazidime-avibactam in Enterobacterales and Pseudomonas aeruginosa, which was observed in 37/55 Enterobacterales and 31/56 P. aeruginosa. As reference methodologies (checkerboard, time-kill curve) are not compatible with the routine of the clinical microbiology laboratories, mATM/CZA is an important alternative to evaluate susceptibility of the combination in a scenario where its clinical use is increasingly important.

Detection of KPC directly from positive blood cultures by MALDI-TOF: From research to the clinical microbiology laboratory routine.

Bloodstream infections (BSI) caused by carbapenem-resistant Gram-negative bacilli (CR-GNB) are a subject of major clinical concern, mainly those associated with carbapenemase-producing isolates. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been proposed to detect specific ß-lactamases, including KPC. We aimed to detect KPC enzyme directly from positive blood cultures using MALDI-TOF MS. Overall, 146 clinical Gram-negative bacilli (46 CR-GNB) recovered from consecutive blood cultures were evaluated. Proteins were extracted using formic acid, isopropyl alcohol, and water and spotted onto a steel target plate using the double-layer sinapinic acid method. The relative ions intensity ≥120 arbitrary units (a.u.) of a peak close to 28,700 m/z indicated the presence of KPC. The results were compared to HRM-qPCR methodology. This specific peak was observed in 11/14 blood bottles with blaKPC positive isolates (78.6% sensitivity), with 3 false-positive results (97.7% specificity). Analysis from colonies reached identical sensitivity (78.6%), but higher specificity (100%). The detection of KPC peaks directly from positive blood cultures using MALDI-TOF MS is feasible and rapid. It's excellent specificity indicates that positive results are consistently associated with the presence of a KPC producer in positive blood culture.

Susceptibility evaluation of novel beta-lactam/beta-lactamase inhibitor combinations against carbapenem-resistant Klebsiella pneumoniae from bloodstream infections in hospitalized patients in Brazil.

Novel beta-lactams/beta-lactamase inhibitors (BIBLI) combinations are commercially available and they have been used for treating carbapenem-resistant Klebsiella pneumoniae (CRKP) infections. Continuous surveillance of susceptibility profile and resistance mechanisms identification are necessary to monitor the evolution of resistance as these agents are used. The purpose of this study was to evaluate susceptibility rates to ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam in CRKP isolates from patients with bloodstream infection screened for a randomized clinical trial in Brazil. Minimum inhibitory concentration (MIC) was determined by gradient diffusion strip method for meropenem, ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam. Carbapenemase genes were detected by multiplex qPCR. KPC-producing isolates showing resistance to any BLBLI and NDM-producing isolates showing susceptibility to any BLBLI were further submitted to whole genome sequencing. From a total of 69 CRKP isolates, 39 were positive for blaKPC, 19 for blaNDM and 11 for blaKPC and blaNDM. KPC-producing isolates demonstrated susceptibility rates above 94% for all BLBLI. Two isolates with resistance to meropenem/vaborbactam showed a Gly and Asp duplication at OmpK36 protein and truncated ompK35 genes. All NDM-producing isolates, including KPC and NDM coproducers, demonstrated susceptibility rates for ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam of 0%, 9.1 to 21.1% and 9.1 to 26.3%, respectively. Five NDM-producing isolates that presented susceptibility to BLBLI also demonstrated alterations in porins. This study demonstrated that, although high susceptibility rates to the BLBLI were found, KPC-2 isolates can also demonstrate resistance due to porin mutations. Additionally, NDM-1 isolates can demonstrate susceptibility in vitro to the BLBLI.

First report of carbapenem-resistant Acinetobacter nosocomialis isolates harboring ISAba1-blaOXA-23 genes in Latin America.

In recent years, different resistance genes have been found in Acinetobacter spp., especially in the species A. baumannii. We describe two isolates of carbapenem-resistant A. nosocomialis harboring ISAba1-blaOXA-23 and blaOXA-51 found in patients from the city of Porto Alegre, southern Brazil. To the best of the authors' knowledge, this is the first report of carbapenem-resistant A. nosocomialis in Latin America.