Dataset Information

High prevalence of bla OXA-23 in Acinetobacter spp. and detection of bla NDM-1 in A. soli in Cuba: report from National Surveillance Program (2010-2012).

ABSTRACT: As a first national surveillance of Acinetobacter in Cuba, a total of 500 Acinetobacter spp. isolates recovered from 30 hospitals between 2010 and 2012 were studied. Acinetobacter baumannii-calcoaceticus complex accounted for 96.4% of all the Acinetobacter isolates, while other species were detected at low frequency (A. junii 1.6%, A. lwoffii 1%, A. haemolyticus 0.8%, A. soli 0.2%). Resistance rates of isolates were 34-61% to third-generation cephalosporins, 49-50% to ?-lactams/inhibitor combinations, 42-47% to aminoglycosides, 42-44% to carbapenems and 55% to ciprofloxacin. However, resistance rates to colistin, doxycycline, tetracycline and rifampin were less than 5%. Among carbapenem-resistant isolates, 75% harboured different bla OXA genes (OXA-23, 73%; OXA-24, 18%; OXA-58, 3%). The bla NDM-1 gene was identified in an A. soli strain, of which the species was confirmed by sequence analysis of 16S rRNA gene, rpoB, rpoB-rpoC and rpoL-rpoB intergenic spacer regions and gyrB. The sequences of bla NDM-1 and its surrounding genes were identical to those reported for plasmids of A. baumannii and A. lwoffi strains. This is the first report of bla NDM-1 in A. soli, together with a high prevalence of OXA-23 carbapenemase for carbapenem resistance in Acinetobacter spp. in Cuba.

SUBMITTER: Quinones D

PROVIDER: S-EPMC4511621 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature

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High prevalence of bla OXA-23 in Acinetobacter spp. and detection of bla NDM-1 in A. soli in Cuba: report from National Surveillance Program (2010-2012).

Quiñones D D Carvajal I I Perez Y Y Hart M M Perez J J Garcia S S Salazar D D Ghosh S S Kawaguchiya M M Aung M S MS Kobayashi N N

New microbes and new infections 20150611

As a first national surveillance of Acinetobacter in Cuba, a total of 500 Acinetobacter spp. isolates recovered from 30 hospitals between 2010 and 2012 were studied. Acinetobacter baumannii-calcoaceticus complex accounted for 96.4% of all the Acinetobacter isolates, while other species were detected at low frequency (A. junii 1.6%, A. lwoffii 1%, A. haemolyticus 0.8%, A. soli 0.2%). Resistance rates of isolates were 34-61% to third-generation cephalosporins, 49-50% to β-lactams/inhibitor combina ...[more]

PMID: 26236494

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Project description:Background and Objective:The emergence of carbapenem-resistant K. pneumoniae (CRKP) continues to escalate and is alarming because of the emergence of pan drug-resistant strains. The objective of this study was to investigate the existence of 12 carbapenemase genes among CRKP clinical isolates. Methods:Ninety-six Klebsiella spp. clinical isolates were collected. The isolates were identified phenotypically and genotypically. These isolates were screened for susceptibility to 24 different antibiotics. The modified Hodge test (MHT) and the Carba Nordmann/Poirel (NP) test were used to phenotypically screen carbapenem-resistant strains for carbapenemase production. Phenotypic characterization of carbapenemases was performed using the combined disk synergy test (CDST). Additionally, the presence of 12 carbapenemase genes in CRKP isolates was investigated. The DNA sequence of bla NDM and bla GES genes was determined. The BOX-PCR technique was used to determine the clonal relationship between CRKP isolates. Results:All carbapenem-resistant isolates were related to K. pneumoniae. Susceptibility testing showed that 19.79% (19/96) of the collected isolates were carbapenem-resistant. Of the CRKP isolates, 68.42% (13/19) tested positive for the MHT and Carba NP test. CDST showed that 42.11% (8/19), 63.16% (12/19), 47.37% (9/19), and 73.68% (14/19) of the CRKP isolates tested positive for the inhibitory effect of clavulanic acid, sulbactam, phenylboronic acid, and tazobactam, respectively, while 84.21% (16/19) and 68.42% (13/16) tested positive for the inhibitory effect of EDTA and mercaptopropionic acid, respectively. It was found that 10.53% (2/19) of the isolates tested positive for the inhibitory effect of sodium chloride. Molecular investigation of carbapenemases showed that 26.32% (5/19), 73.68% (14/19), 21.05% (4/19), 10.53% (2/19), and 5.26% (1/19) of the isolates tested positive for bla NDM, bla OXA-48, bla OXA-181, bla OXA-51, and bla OXA-23, respectively. None of the isolates tested positive for bla OXA-40 and bla OXA-58. Two allelic variants of bla NDM (bla NDM-1 and bla NDM-25) were detected. BOX-PCR revealed high clonal relatedness between CRKP isolates. Conclusion:MHT was more sensitive than Carba NP test for evaluating carbapenemase production and class D carbapenemase genes were the most prevalent of the 12 carbapenemase genes that were evaluated.

Project description:Carbapenem-resistant Acinetobacter baumannii spp. are increasingly important pathogens with limited treatment options, and there is limited knowledge on the environmental factors contributing to their spread. We determined the occurrence of carbapenem-resistant A. baumannii in hospital wastewater and their phylogenetic relationships with clinical A. baumannii isolates. Grab samples of raw and treated hospital wastewater were collected monthly at the University College Hospital, Ibadan, Nigeria, between March 2021 and February 2022. Acinetobacter baumannii strains were selectively isolated and identified using VITEK2, and their whole genomes were sequenced on an Illumina platform. We performed antimicrobial susceptibility testing and in silico genomic characterization of the strains and determined their phylogenetic relationships to previously characterized clinical A. baumannii strains from Nigeria. A. baumannii complex isolates were recovered from wastewater throughout the study. Of the 82 isolates identified based on whole-genome sequences, 77 were A. baumannii. A. baumannii isolates had high resistance rates (≥48.1%) to 10 of 12 antimicrobials tested, and majority (42/77, 54.5%) were resistant to carbapenems, with bla NDM-1 being the most common (24/77, 31.2%) carbapenem resistance gene detected, followed by bla OXA-23 (n = 22, 28.6%). There was no statistically significant difference in carbapenem resistance rates or carbapenem gene carriage between the raw and treated wastewater isolates. Most of the isolates belonged to novel or sparsely described lineages, some of which were closely related to clinical isolates. The release of inadequately treated hospital wastewater into the environment may contribute to the increased spread of carbapenem-resistant and clinically important A. baumannii lineages in Ibadan, Nigeria. IMPORTANCE Acinetobacter baumannii is a leading cause of hospital-associated infections globally. A. baumannii reservoirs outside hospital settings are still unknown, and their occurrence in the environment is linked to clinical and anthropogenic activities. Although the risk of transmission of A. baumannii from environmental sources to humans is not fully understood, these sources pose significant risks for the continued dissemination of A. baumannii and their resistance traits. This study provides evidence that diverse and clinically relevant A. baumannii strains, many of which are resistant to carbapenems, are constantly being discharged into the environment through inadequately treated hospital wastewater. We further elucidate potential transmission routes between the environment and clinical infections and demonstrate the high prevalence of carbapenem resistance genes on highly mobile transposons among these strains. Our findings highlight the pressing need to address hospital wastewater as a crucial factor in curtailing the spread of carbapenem-resistant A. baumannii.

Project description:Carbapenem-resistant Acinetobacter baumannii (CRAB), which belonged to global clones 1 (GC1) or 2 (GC2), has been widely reported and become a global threat. However, non-GC1 and non-GC2 CRAB strains are not well-studied, especially for those with rare phenotype. Here, one pyomelanin-producing CRAB strain (A. baumannii DETAB-R21) was isolated from oral swab in the ICU. Antimicrobial susceptibility testing showed it was resistant to carbapenems, ceftazidime, levofloxacin, and ciprofloxacin. DETAB-R21 was ST164Pas and ST1418Oxf with KL47 and OCL5, respectively. Whole-genome sequencing (WGS) analysis revealed chromosome contained three copies of blaOXA-23 on three 4,805-bp Tn2006 composite transposons with various novel 9-bp target site duplications (TSD). A Tn125-like structure, including blaNDM-1, a novel 4,343 bp composite transposon encoding blaCARB-16, and three prophage regions were also identified. Importantly, hmgA was interrupted by a Tn2006 and contributed to pyomelanin production and further confirmed by hmgA overexpression. Furthermore, A. baumannii irradiated with UV light, DETAB-R21 showed a higher relatively survival rate compared to a control strain that did not produce pyomelanin. No effects of pyomelanin were observed on disinfectants susceptibility, growth, or virulence. In conclusion, pyomelanin-producing CRAB carrying the blaNDM-1 and blaOXA-23 genes embedded in the bacterial chromosome is of grave concern for health care settings, highlighting the need for effective measures to prevent further dissemination. IMPORTANCE Pyomelanin production is a quite rare phenotype in A. baumannii. Moreover, the mechanisms leading to the pyomelanin production was still unclear. Here, we for the first time, confirmed the mechanism of pyomelanin production, and further investigated the impact of pyomelanin on disinfectants susceptibility, growth, virulence, and UV irradiation. More importantly, many mobile genetic elements (MGEs), including three copies of Tn2006 composite transposons, one copy of blaNDM-1 on the Tn125-like structure and three prophage regions, were identified in the chromosome, demonstrated strong plasticity of A. baumannii genome. Our study provides important insights into the new rare ST164Pas A. baumannii strain with high level carbapenem resistance, which is of great threat for patients. These findings will provide important insights into the resistance gene transfer via transposition events and further spread in the clinic.

Project description:Purpose:A novel variant of OXA-23, named OXA-423, was identified in an Acinetobacter baumannii clinical isolate. The aim of this study was to analyse the resistance phenotype of OXA-423. Methods:The A. baumannii strain WY-0713 was isolated from an intensive care unit patient. PCR was used to detect the bla OXA-23-like genes. Amplifying, cloning and sequencing were performed for the complete bla OXA-23-like. The novel bla OXA-423 and its ancestor bla OXA-23 were cloned into the expression vector pET-28b(+), and transformed into E. coli Rosetta (DE3) for antibiotic susceptibility testing. SDS-PAGE, modified Hodge test and CarbaNP test were used for detecting the expression of OXA-423 and OXA-23. Results:PCR screening of A. baumannii WY-0713 was positive for bla OXA-23-like genes. Sequencing of the PCR product identi?ed a novel bla OXA-23-like, named bla OXA-423 which encoding OXA-423. OXA-423 differed from OXA-23 by a crucial amino acid substitution (Val128Ala). The V128A substitution was located at the conserved active-site motifs SAV of OXA-23. Antibiotic susceptibility testing performed using isogenic E. coli showed that the MICs of E. coli Rosetta (pET-OXA-423) for penicillins and carbapenems were lower (reduced MICs 4-fold to 16-fold) than that of E. coli Rosetta (pET-OXA-23). The MICs of cefotaxime, ceftazidime and aztreonam for both transformants remained the same as the acceptor strain. Moreover, OXA-423 was slightly inhibited by sulbactam, clavulanic acid and tazobactam. SDS-PAGE analysis showed that OXA-423 and OXA-23 were conspicuously expressed. Modified Hodge test and CarbaNP test were positive demonstrated both of them were functional. Conclusion:OXA-423, the first report of an amino acid substitution located at conserved active-site motifs of OXA-23, conferred lower MIC values of penicillins and carbapenems as compared with OXA-23, while without affecting the resistance pro?les of expanded-spectrum cephalosporins and aztreonam.

Project description:The Acinetobacter calcoaceticus-baumannii (ACB) complex, also known as ACB complex, consists of four bacterial species that can cause opportunistic infections in humans, especially in hospital settings. Conventional therapies for susceptible strains of the ACB complex include broad-spectrum cephalosporins, β-lactam/β-lactamase inhibitors, and carbapenems. Unfortunately, the effectiveness of these antibiotics has declined due to increasing rates of resistance. The predominant resistance mechanisms identified in the ACB complex involve carbapenem-resistant (CR) oxacillinases and metallo-β-lactamases (MBLs). This research, conducted at Kathmandu Model Hospital in Nepal, sought to identify genes associated with CR, specifically blaNDM-1, blaOXA-23-like, and blaOXA-24-like genes in carbapenem-resistant Acinetobacter calcoaceticus-baumannii (CR-ACB) complex. Additionally, the study is aimed at identifying the ACB complex through the sequencing of the 16s rRNA gene. Among the 992 samples collected from hospitalized patients, 43 (approximately 4.334%) tested positive for the ACB complex. These positive samples were mainly obtained from different hospital units, including intensive care units (ICUs); cabins; and neonatal, general, and maternity wards. The prevalence of infection was higher among males (58.14%) than females (41.86%), with the 40-50 age group showing the highest infection rate. In susceptibility testing, colistin and polymyxin B exhibited a susceptibility rate of 100%, whereas all samples showed resistance to third-generation cephalosporins. After polymyxins, gentamicin (30.23%) and amikacin (34.88%) demonstrated the highest susceptibility. A substantial majority (81.45%) of ACB complex isolates displayed resistance to carbapenems, with respiratory and pus specimens being the primary sources. Polymerase chain reaction (PCR) revealed that the primary CR gene within the ACB complex at this hospital was bla OXA-23-like, followed by bla NDM-1. To ensure the accuracy of the phenotypic assessment, 12 samples were chosen for 16s rRNA sequencing using Illumina MiSeq™ to confirm that they are Acinetobacter species. QIIME 2.0 analysis confirmed all 12 isolates to be Acinetobacter species. In the hospital setting, a substantial portion of the ACB complex carries CR genes, rendering carbapenem ineffective for treatment.

Project description:Aim of this study was to genetically characterize two carbapenemase-producing Escherichia coli strains obtained from a pediatric patient affected by diarrhea, expressing OXA-181 and/or NDM-5 type enzymes. The above microorganisms were collected in the same Desenzano hospital (Northern Italy) where the bla NDM- 5 gene was detected for the first time in Italy 3 years ago. One strain (5P), belonged to sequence type ST405/ST477 (according to Pasture/Oxford schemes) and serotype O102:H6. It was characterized by a 130562 bp multi-replicon plasmid IncFII/IncFIA/IncFIB (pVSI_NDM-5) enclosing two main antibiotic resistance islands: (i) ARI-I, 10030 bp in size, carried genes coding for β-lactam- (bla OXA- 1, bla CTX-M- 15), fluoroquinolone/aminoglycoside- (aac(6')-lb-cr) and phenicol- resistance (catB3), (ii) ARI-II, 15326 bp in size, carried genes coding for sulfonamide- (sul1), β-lactam- (bla NDM- 5, bla TEM- 1 B), phenicol- (catB3), trimethoprim- (dfrA17), antiseptic- (qacEΔ1), and aminoglycoside- (aadA5, rmtB) resistance. The other isolate (5M), belonged to sequence type ST2659/ST759 and serotype O50/02:H18, and carried four plasmids: a 153866 bp multi-replicon IncFII/IncFIA/IncFIB (pISV_IncFII_NDM-5), an 89866 bp IncI1 plasmid, a 51480 bp IncX3 plasmid (pISV_IncX3_OXA181), and a 41143 bp IncI plasmid (pISV_IncI_CMY-42). pISV_IncFII_NDM-5 carried two main antibiotic resistance islands: (i) ARI-III, 12220 bp in size, carried genes coding for β-lactam- (bla OXA- 1), fluoroquinolone/aminoglycoside- (aac(6')-lb-cr), tetracycline- (tet(B)) and phenicol- resistance (catB3, catA1), and ii) ARI-IV, 26527 bp in size, carried determinants coding for macrolide- (erm(B), mph(A)), sulfonamide- (sul1), beta-lactam- (bla NDM- 5, bla TEM- 1 B), trimethoprim- (dfrA14, dfrA12), antiseptic- (qacEΔ1), and aminoglycoside- resistance (aadA5). pISV_IncI_CMY-42 harbored the bla CMY- 42 gene coding for beta-lactam resistance, pISV_IncX3_OXA181 harbored genes encoding fluoroquinolone- (qnrS1) and beta-lactams- resistance (bla OXA- 181). In conclusion, the detection of two different NDM-5 E. coli strains from a pediatric patient with a history of travel to the Far East countries strongly highlight an increasing trend and risk of importation from such areas.

Dataset Information

High prevalence of bla OXA-23 in Acinetobacter spp. and detection of bla NDM-1 in A. soli in Cuba: report from National Surveillance Program (2010-2012).

Publications

High prevalence of bla OXA-23 in Acinetobacter spp. and detection of bla NDM-1 in A. soli in Cuba: report from National Surveillance Program (2010-2012).

Similar Datasets

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