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Mingyue Sun, Weiqiang Xiao, Qingxia Xu Department of Clinical Laboratory, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Zhengzhou, Henan, People’s Republic of ChinaCorrespondence: Qingxia Xu, Department of Clinical Laboratory, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Dongming Road No. 127, Zhengzhou, Henan Province, People’s Republic of China, Tel +860371-65587147, Email qxiaxu@126.comObjective: Klebsiella michiganensis is an emerging pathogen. In this context, we characterised a strain fxq isolated from a cerebrospinal fluid specimen of a patient with tentorial meningioma, and the K. michiganensis isolate produced carbapenemases of KPC and NDM types.Methods: The Phoenix 100 Automated Microbiology System, MALDI-TOF and whole-genome sequencing were used to identify the species. Anti-microbial susceptibility testing was also conducted with the Phoenix 100. The plasmid locations of the blaKPC-2 and blaNDM-1 genes were determined by S1-nuclease pulsed-field gel electrophoresis and Southern blot. The transfer capacity of plasmids carrying blaKPC-2 and blaNDM-1 was investigated by conjugation experiments, and the resistance plasmid stability was evaluated by culture and subculture. K. michiganensis subtypes were identified by multi-locus sequence typing. We performed whole-genome sequencing to confirm species, characterise plasmids and analyse core genes.Results: fxq was originally identified as Klebsiella oxytoca and showed resistance to imipenem and meropenem, but whole-genome sequencing identified it to be K. michiganensis. The strain fxq belonged to the novel sequence type 202 (ST202) and carried the blaKPC-2 and blaNDM-1 genes located on the pB_KPC InFIA and pE_NDM IncU plasmids, respectively. The blaKPC-2-carrying plasmid was successfully transferred to Escherichia coli EC600 by conjugation, whereas the blaNDM-1 gene on the pE_NDM plasmid was not. The pB_KPC and pE_NDM plasmids demonstrated high stability.Conclusion: This work is the first report on a carbapenem-resistant clinical isolate K. michiganensis ST202 harbouring the blaKPC-2 and blaNDM-1 genes encoded by the IncFIA and IncU plasmids, respectively.Keywords: Klebsiella michiganensis, IncU plasmid, carbapenemase gene, NDM, KPC

Faecal contamination of surface waters has the potential to spread not only pathogenic organisms but also antimicrobial resistant organisms. During the bathing season of 2021, weekly water samples, from six selected coastal bathing locations (n  = 93) and their freshwater tributaries (n  = 93), in Northern Ireland (UK), were examined for concentrations of faecal indicator bacteria Escherichia coli and intestinal enterococci. Microbial source tracking involved detection of genetic markers from the genus Bacteroides using PCR assays for the general AllBac marker, the human HF8 marker and the ruminant BacR marker for the detection of human, and ruminant sources of faecal contamination. The presence of beta-lactamase genes bla OXA-48, bla KPC, and bla NDM-1 was determined using PCR assays for the investigation of antimicrobial resistance genes that are responsible for lack of efficacy in major broad-spectrum antibiotics. The beta-lactamase gene bla OXA-48 was found in freshwater tributary samples at all six locations. bla OXA-48 was detected in 83% of samples that tested positive for the human marker and 69% of samples that tested positive for the ruminant marker over all six locations. This study suggests a risk of human exposure to antimicrobial resistant bacteria where bathing waters receive at least episodically substantial transfers from such tributaries. [ABSTRACT FROM AUTHOR]

Komla Mawunyo Dossouvi,1 Ayawovi Selom Ametepe2 1Department of Microbiology, DGlobal Health Research Institute, Lomé, Togo; 2Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USACorrespondence: Komla Mawunyo Dossouvi, Tel +22896505659, Email dossouvikomlamawunyo@gmail.comBackground: The World Health Organization (WHO) has classified carbapenem-resistant Enterobacteriaceae, Pseudomonas aeruginosa (P. aeruginosa), and Acinetobacter baumannii (A. baumannii) as high-priority pathogens, and carbapenem-resistant bacteria (CRB) have been reported to spread between humans, animals, and the environment.Objective: This study aimed to conduct a systematic review of carbapenem resistance in animals, foods, and the environment on the African continent and to provide recommendations and perspectives for better prevention and control of carbapenem resistance in Africa.Results: A total of 137 research articles collected from 2009 to 2023 were selected for this review, including articles reporting carbapenem-resistant bacteria in animals (81/137; 59.1%), the environment (66/137; 48.2%), and foods (26/137; 19%). Carbapenem-resistant bacterial species belonged to 31 genera and 17 families, including mainly Escherichia spp. (68/127; 53.5%); Klebsiella spp. (45/127; 35.4%); Pseudomonas spp. (20/127; 15.7%), Enterobacter spp. (19/127; 15%) and Acinetobacter spp. (15/127; 11.8%). The prevalence of CRBs by country ranged from 1.1% to 48.5%, and the pooled prevalence of CRBs isolated from animal-environment-food in Africa was 19.1% (2804/14,684; Standard Deviation = 15). Twenty carbapenemase families belonging to A, B, C, and D Ambler classes were reported, including mainly carbapenemase genes from blaOXA (44/84; 52.4%), blaNDM (34/84; 40.5%), blaSHV (23/84; 27.4%), blaKPC (22/84; 26.2%), blaVIM (19/84; 22.6%), and blaIMP (12/84; 14.3%) families. The reported mobile genetic elements (MGE) carrying carbapenemase-encoding genes included plasmids (16/19; 84.2%), integrons (3/19; 15.8%), transposons (3/19; 15.8%), and insertion sequences (2/19; 10.5%). blaOXA-48 was often carried by (60kb-65kb) IncL/M-type pOXA-48 plasmids, while blaNDM-5 was often carried by (45– 50kb) IncX-type plasmids. Moreover, 25 articles investigated and reported virulent and hypervirulent CRBs that carried multiple virulence factors.Conclusion: Animal-environment-food ecosystems would constitute reservoirs of CRBs involved in human infections. The One Health approach and constant collaboration between governments are necessary to drastically reduce the mortality rates linked to antimicrobial resistance.Keywords: carbapenem resistance, animal-environment-food, Africa, mobile genetic element, carbapenemase gene

The emergence of carbapenem-resistant organisms (CROs) has become a great challenge alarming the public health community. Thus, the current study was conducted to investigate the occurrence of CROs among pet animals suffering from respiratory illness. Nasal swabs from 100 pet animals (51 dogs and 49 cats) showing respiratory illness were screened for CROs. The obtained swabs were streaked onto CHROMagar mSuper CARBATM medium followed by sub-culturing on MacConkey agar. Colonies were identified by cultural characteristics, Gram staining, and biochemical tests as well as molecular techniques. Then, the identified isolates were confirmed to be CROs after being non-susceptible to at least one of four carbapenem antibiotics using the Kirby-Bauer method. The confirmed CRO isolates were also investigated on molecular basis for carbapenemase-encoding genes (blaNDM, blaKPC, blaOXA-48, blaVIM, blaIMP). Out of 100 pet animals, 6 yielded CROs with an overall occurrence rate 6% (3.9% for all tested dogs and 8.2% for all tested cats). The obtained CRO isolates were Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter cloacae with the following distribution among the examined animals 3%, 1%, 1%, and 1%, respectively. BlaNDM was the only detected carbapenemase-encoding gene among the isolates and it was detected in two cat isolates. In conclusion, the results of the current study highlight the emergence of carbapenem-resistant organisms among pet animals suffering from respiratory illness which may have a possible public health risk. [ABSTRACT FROM AUTHOR]

Abstract Purpose Bloodstream infection (BSI) caused by Carbapenem-Resistant Enterobacteriaceae (CRE) are associated with poor outcomes in hematological patients. The aim of this study was to identify risk factors for mortality and evaluate the value of epidemiological feature of carbapenemases in guiding antimicrobial treatment options. Methods Hematological patients with monomicrobial CRE BSI between January 2012 and April 2021 were included. The primary outcome was all-cause mortality 30 days after BSI onset. Results A total of 94 patients were documented in the study period. Escherichia coli was the most common Enterobacteriaceae, followed by Klebsiella pneumoniae. 66 CRE strains were tested for carbapenemase genes, and 81.8% (54/66) were positive, including NDM (36/54), KPC (16/54), IMP (1/54). Besides, one E. coli isolate was found to express both NDM and OXA-48-like genes. Overall, 28 patients received an antimicrobial treatment containing ceftazidime-avibactam (CAZ-AVI), of which 21 cases were combined with aztreonam. The remaining 66 patients were treated with other active antibiotics (OAAs). The 30-day mortality rate was 28.7% (27/94) for all patients, and was only 7.1% ((2/28) for patients treated with CAZ-AVI. In multivariate analysis, the presence of septic shock at BSI onset (OR 10.526, 95% CI 1.376–76.923) and pulmonary infection (OR 6.289, 95% CI 1.351–29.412) were independently risk factors for 30-day mortality. Comparing different antimicrobial regimens, CAZ-AVI showed a significant survive benefit than OAAs (OR 0.068, 95% CI 0.007–0.651). Conclusion CAZ-AVI-containing regimen is superior to OAAs for CRE BSI. As the predominance of blaNDM in our center, we recommend the combination with aztreonam when choose CAZ-AVI.

Carbapenem-resistant (CR) Klebsiella oxytoca complex can be associated with high mortality, emerging as a new threat to the public health. K. oxytoca complex is phylogenetically close to K. pneumoniae, one of most common species associated with multidrug resistance in Enterobacterale. The latest research showed that K. oxytoca is a complex of six species. Currently, the epidemiological and genomic characteristics of CR K. oxytoca complex in China are still unclear. Here, we conducted a multi-center study on 25 CR K. oxytoca complex collected from five representative regions in China. These isolates were, respectively, recovered from respiratory tract (12 cases, 48.0%), abdominal cavity (5 cases, 20.0%), blood (4 cases, 16.0%), urine tract (3 cases, 12.0%) and skin or soft tissue (1 cases, 4.0%). Among them, 32.0% (8/25) of patients infected with K. oxytoca complex had a poor prognosis. In this study, three K. oxytoca complex species were detected, namely K. michiganensis, K. oxytoca and K. pasteurii, among which K. michiganensis was the most common. Three carbapenemase genes were identified, including blaNDM-1 (10, 38.5%), blaKPC-2 (9, 34.6%) and blaIMP (6 blaIMP-4 and 1 blaIMP-8; 7, 26.9%). Subsequent multilocus sequence typing identified various sequence types (STs), among which ST43, ST92 and ST145 were relatively common. Different from the clonal dissemination of high-risk carbapenem-resistant K. pneumoniae strains, our research revealed a polyclonal dissemination characteristic of CR K. oxytoca complex in China. S1-nuclease PFGE and Southern blot experiment showed that carbapenemase genes were encoded in plasmids of different sizes. Two blaNDM-harboring plasmids were subsequently sequenced, and were characterized to be IncX3 and IncC incompatibility groups, respectively. This is the first multi-center study of CR K. oxytoca complex in China, which improved our understanding of the prevalence and antimicrobial resistance characteristics of CR K. oxytoca complex in China. [ABSTRACT FROM AUTHOR]

Purpose: Bloodstream infection (BSI) caused by Carbapenem-Resistant Enterobacteriaceae (CRE) are associated with poor outcomes in hematological patients. The aim of this study was to identify risk factors for mortality and evaluate the value of epidemiological feature of carbapenemases in guiding antimicrobial treatment options. Methods: Hematological patients with monomicrobial CRE BSI between January 2012 and April 2021 were included. The primary outcome was all-cause mortality 30 days after BSI onset. Results: A total of 94 patients were documented in the study period. Escherichia coli was the most common Enterobacteriaceae, followed by Klebsiella pneumoniae. 66 CRE strains were tested for carbapenemase genes, and 81.8% (54/66) were positive, including NDM (36/54), KPC (16/54), IMP (1/54). Besides, one E. coli isolate was found to express both NDM and OXA-48-like genes. Overall, 28 patients received an antimicrobial treatment containing ceftazidime-avibactam (CAZ-AVI), of which 21 cases were combined with aztreonam. The remaining 66 patients were treated with other active antibiotics (OAAs). The 30-day mortality rate was 28.7% (27/94) for all patients, and was only 7.1% ((2/28) for patients treated with CAZ-AVI. In multivariate analysis, the presence of septic shock at BSI onset (OR 10.526, 95% CI 1.376–76.923) and pulmonary infection (OR 6.289, 95% CI 1.351–29.412) were independently risk factors for 30-day mortality. Comparing different antimicrobial regimens, CAZ-AVI showed a significant survive benefit than OAAs (OR 0.068, 95% CI 0.007–0.651). Conclusion: CAZ-AVI-containing regimen is superior to OAAs for CRE BSI. As the predominance of blaNDM in our center, we recommend the combination with aztreonam when choose CAZ-AVI. [ABSTRACT FROM AUTHOR]

Background & Objectives: Klebsiella pneumoniae is a significant cause of nosocomial infections. This bacterium survives in difficult conditions by forming biofilms in hospital equipment and causes severe infections. On the other hand, the emergence and spread of carbapenem resistance among bacteria and biofilm production is a current health concern. There are controversial findings about the relevance of this issue. This study aimed to evaluate the relationship between biofilm formation and carbapenem resistance among clinical isolates. Materials & Methods: A total of 160 isolates of Klebsiella pneumoniae were collected. Molecular methods were used to detect resistance genes. Subsequently, the ability to produce biofilms in isolates with resistance genes was assessed. Finally, the correlation of biofilm formation among resistant isolates was calculated using χ2 test. Results: 79 imipenem-resistant isolates were obtained. 46 isolates (66.66%) containing VIM gene, 36 isolates (52.17%) containing OXA-48 gene, five isolates (7.24%) containing NDM gene, Six isolates (8.69%) containing gene IMP and five isolates (7.24%) also had KPC gene. The results showed a significant correlation between the ability to form biofilms and the presence of carbapenem-resistant genes. Conclusion: Increased carbapenem resistance in Klebsiella pneumoniae isolates and its association with biofilm formation is severe warning for basic measures to combat this phenomenon.

ABSTRACT: Objectives: The prevalence of carbapenem-resistant Enterobacterales (CRE) has increased rapidly worldwide in the last two decades. CRE infection poses a huge challenge for today's clinical therapy. Rapid and accurate detection of clinical CRE isolates can avoid inappropriate antimicrobial treatment and reduce mortality. However, existing detection methods are either time consuming, expensive or inaccurate, making them unable to fully meet clinical demands. In this study, the HB&L system was designed to distinguish CRE from carbapenem-susceptible Enterobacterales (CSE), as it can accelerate the growth of bacteria, detect both carbapenemase-producing CRE (CP-CRE) and non-CP-CRE isolates in real time, and provide time–kill curves. Methods: The broth microdilution method and PCR and sequencing were used as the reference methods to identify CRE and carbapenemase-producing Enterobacterales (CPE) isolates, respectively. Three methods for detecting CRE isolates, including the Carba NP test, modified carbapenem inactivation method (mCIM) and HB&L system, were evaluated. Results: The accuracy of the HB&L system was extremely high with 100% sensitivity and 96.0% specificity at only 6 h of culture time for detecting CRE. Time–kill curves may provide information on effective treatment options for clinicians. This system is superior to the mCIM (20–24 h detection time; 90.6% sensitivity and 96.6% specificity) and Carba NP test (2 h detection time; 85.2% sensitivity and 98.4% specificity), which are only designed to detect CP-CRE. Conclusion: The HB&L system is promising for wide application for detection of clinical CRE in hospitals.

Carbapenemase-producing Klebsiella pneumoniae (CP-Kp) is a real global health threat. Environmental reservoirs of resistance gene determinats, such as effluents of hospital wastewaters, are acquiring increased relevance in the selection of plasmid-encoded carbapenemase genes. The presence of Hg in environmental reservoirs may exert a positive selective pressure on tolerant bacteria, favoring the co-transfer of carbapenemase genes and mer operons. In our study, 63 CP-Kp isolates were screened for mer operons by whole genome sequencing (MySeq). Conjugation assays were performed with 24 out of 63 CP-Kp isolates harboring the mer operon. Ten transconjugants (Tc-Kp) were selected with Hg. Plasmid DNA of Tc-Kp was extracted and sequenced using single-molecule real-time (SMRT) technology (PacBio, Sequel II system) with later annotation. Plasmid analysis revealed that Tc-Kp from blaIMP-like (n = 3) showed a single plasmid belonging to IncC group with two complete mer operon next to blaIMP-like. Tc-Kp from blaVIM-1 (n = 2) harbored two plasmids, one with blaVIM-1 in an IncL, and mer operon was in an IncFIB plasmid. Tc-Kp from blaOXA-48-like (n = 5) showed 2 plasmids. blaOXA-48-like was found in an IncL plasmid, whereas mer operon was (i) in an IncR plasmid associated with blaCTX-M-15 in 3 Tc-Kp-OXA-48-like, (ii) in an IncC plasmid associated with blaCMY-2 in 1 Tc-Kp-OXA-48-like, (iii) and in an IncFIB plasmid associated with blaCTX-M-15 in 1 Tc-Kp-OXA-48-like. This is, to our knowledge, the first study to describe in K. pneumoniae producing plasmid-encoded carbapenemase, the potential impact of Hg in the co-transfer of mer operons and carbapenemase genes located in the same or different plasmids. Key points: • Environmental reservoirs are playing an important role in the selection of carbapenemase genes. • Conjugation assays, selecting with Hg, obtained 10 transconjugants with carbapenemase genes. • mer operons were located in the same or different plasmids than carbapenemase genes. [ABSTRACT FROM AUTHOR]

Faecal contamination of surface waters has the potential to spread not only pathogenic organisms but also antimicrobial resistant organisms. During the bathing season of 2021, weekly water samples, from six selected coastal bathing locations (n = 93) and their freshwater tributaries (n = 93), in Northern Ireland (UK), were examined for concentrations of faecal indicator bacteria Escherichia coli and intestinal enterococci. Microbial source tracking involved detection of genetic markers from the genus Bacteroides using PCR assays for the general AllBac marker, the human HF8 marker and the ruminant BacR marker for the detection of human, and ruminant sources of faecal contamination. The presence of beta-lactamase genes blaOXA-48, blaKPC, and blaNDM-1 was determined using PCR assays for the investigation of antimicrobial resistance genes that are responsible for lack of efficacy in major broad-spectrum antibiotics. The beta-lactamase gene blaOXA-48 was found in freshwater tributary samples at all six locations. blaOXA-48 was detected in 83% of samples that tested positive for the human marker and 69% of samples that tested positive for the ruminant marker over all six locations. This study suggests a risk of human exposure to antimicrobial resistant bacteria where bathing waters receive at least episodically substantial transfers from such tributaries., (© The Author(s) 2024. Published by Oxford University Press on behalf of Applied Microbiology International.)

Background & Objectives: Klebsiella pneumoniae is a significant cause of nosocomial infections. This bacterium survives in difficult conditions by forming biofilms in hospital equipment and causes severe infections. On the other hand, the emergence and spread of carbapenem resistance among bacteria and biofilm production is a current health concern. There are controversial findings about the relevance of this issue. This study aimed to evaluate the relationship between biofilm formation and carbapenem resistance among clinical isolates. Materials & Methods: A total of 160 isolates of Klebsiella pneumoniae were collected. Molecular methods were used to detect resistance genes. Subsequently, the ability to produce biofilms in isolates with resistance genes was assessed. Finally, the correlation of biofilm formation among resistant isolates was calculated using χ2 test. Results: 79 imipenem-resistant isolates were obtained. 46 isolates (66.66%) containing VIM gene, 36 isolates (52.17%) containing OXA-48 gene, five isolates (7.24%) containing NDM gene, Six isolates (8.69%) containing gene IMP and five isolates (7.24%) also had KPC gene. The results showed a significant correlation between the ability to form biofilms and the presence of carbapenem-resistant genes. Conclusion: Increased carbapenem resistance in Klebsiella pneumoniae isolates and its association with biofilm formation is severe warning for basic measures to combat this phenomenon. [ABSTRACT FROM AUTHOR]

Carbapenem non-susceptible Acinetobacter baumannii (CNSAB) is an important pathogen that causes nosocomial bacteremia among critically ill patients worldwide. The magnitude of antibiotic resistance of A. baumanii in Indonesia is expected to be significant; however, the data available are limited. The aim of this study was to analyze the genetic profiles of CNSAB isolates from patients with bacteremia in Indonesia. CNSAB isolates from blood cultures of bacteremia patients in 12 hospitals in Indonesia were included. The blood cultures were conducted using the BacT/Alert or BACTEC automated system. The CNSAB were identified with either Vitek 2 system or Phoenix platform followed by a confirmation test using a multiplex polymerase chain reaction (PCR) assay, targeting the specific gyrB gene. The carbapenemase genes were detected by multiplex PCR. In total, 110 CNSAB isolates were collected and were mostly resistant to nearly all antibiotic classes. The majority of CNSAB isolates were susceptible to tigecycline and trimethoprim-sulfamethoxazole (TMP-SMX), 45.5% and 38.2%, respectively. The blaOXA-51-like gene was identified in all CNSAB isolates. Out of the total, 83.6% of CNSAB isolates had blaOXA-23-like gene, 37.3% blaOXA-24-like gene, 4.5% blaNDM-1 gene, 0.9% blaIMP-1 gene, and 0.9% blaVIM gene. No blaOXA-48-like gene was identified. The blaOXA-23-like gene was the predominant gene in all except two hospitals. The presence of the blaOXA-24-like gene was associated with resistance to tigecycline, amikacin, TMP-SMX and cefoperazone-sulbactam, while blaOXA-23-like gene was associated with resistance to TMP-SMX and cefoperazone-sulbactam. In conclusion, the blaOXA-23-like gene was the predominant gene among CNSAB isolates throughout Indonesia. A continuous national surveillance system needs to be established to further monitor the genetic profiles of CNSAB in Indonesia.

Introduction: Multidrug resistant (MDR) Acinetobacter baumanii (A. baumannii) strains have emerged as novel nosocomial pathogens threatening patients' lives, especially in intensive-care units (ICUs). This study aims to determine the prevalence of carbapenemase genes and CTX-M-15 and the resistance pattern of carbapenemase producing isolates.Methods: A total of 530 clinical specimens were collected from patients suffering from different infections, antibiotic susceptibility test was performed using kirby-bauer disk diffusion method. ESβL production was detected phenotypically by double-disc synergy test (DDST). Carbapenemase production was tested by Modified Hodge Test (MHT). Then, these isolates were tested for MBL detection by disc potentiation test. Carbapenemase encoding genes (VIM, IMP, GIM and SPM, OXA-51, OXA-23 and OXA-143) and CTX-M-15 were tested by polymerase chain reaction (PCR).Results: Out of 530 samples, 20 bacterial isolates were identified as A. baumannii from different infectious cases, 35% of isolates were ESBL-producers. Eleven isolates were resistant to imipenem (4 isolates) and meropenem (7 isolates). All carbapenem resistant isolates were MHT positive. Nine (45%) isolates were confirmed as A. baumannii by OXA-51 (all were carbapenem resistant). Distribution of IMP, VIM, GIM and SPM, OXA-23, OXA-143 and CTX-M-15 by PCR were 55, 50, 50, 25, 35, 45 and 33% respectively.Conclusion: The high prevalence of resistance genes and the resistance pattern of the isolates indicate that the detection of ESBLs and MBLs phenotypically and genotypically with the study of the resistance pattern of the isolates is critically important for the surveillance of drug resistance in the hospital environment. [ABSTRACT FROM AUTHOR]

Background/Purpose: The purpose of this study is to investigate the predominant clones of carbapenem-resistant Acinetobacter baumannii (CRAB) in our hospital in Taiwan by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) technique. Methods: We collected 108 non-duplicate A. baumannii clinical blood isolates from January 2012 to December 2013 in MacKay Memorial Hospital. PFGE and MLST were used for typing the A. baumannii isolates and for investigation of the predominant clones. Bacteria isolates were screened by polymerase chain reaction for the presence of the carbapenemase-encoding genes. Results: All 108 isolates were classified as 33 pulsotypes by PFGE. The predominant clones were pulsotype 10 (12.04%) in 2012 and pulsotype 8 (16.67%) in 2013, respectively. The 31 predominant pulsotype isolates were typed by MLST, and ST787 (54.84%) and ST455 (45.16%) were identified. All isolates carried blaOXA-51-like genes, and blaOXA-23-like genes was founded in 101 isolates (93.52%). Other identified resistance genes included blaOXA-24-like and blaOXA-IMP. Conclusion: To the best of our knowledge, this study is the first to describe the microbiological characteristics of CRAB ST787, which carried high genetic resistance to carbapenem, but remained susceptible to colistin. CRAB ST787 was the predominant clone in our hospital in the study period.

Carbapenem-resistant (CR) Klebsiella oxytoca complex can be associated with high mortality, emerging as a new threat to the public health. K. oxytoca complex is phylogenetically close to K. pneumoniae , one of most common species associated with multidrug resistance in Enterobacterale. The latest research showed that K. oxytoca is a complex of six species. Currently, the epidemiological and genomic characteristics of CR K. oxytoca complex in China are still unclear. Here, we conducted a multi-center study on 25 CR K. oxytoca complex collected from five representative regions in China. These isolates were, respectively, recovered from respiratory tract (12 cases, 48.0%), abdominal cavity (5 cases, 20.0%), blood (4 cases, 16.0%), urine tract (3 cases, 12.0%) and skin or soft tissue (1 cases, 4.0%). Among them, 32.0% (8/25) of patients infected with K. oxytoca complex had a poor prognosis. In this study, three K. oxytoca complex species were detected, namely K. michiganensis , K. oxytoca and K. pasteurii , among which K. michiganensis was the most common. Three carbapenemase genes were identified, including bla NDM-1 (10, 38.5%), bla KPC-2 (9, 34.6%) and bla IMP (6 bla IMP-4 and 1 bla IMP-8 ; 7, 26.9%). Subsequent multilocus sequence typing identified various sequence types (STs), among which ST43, ST92 and ST145 were relatively common. Different from the clonal dissemination of high-risk carbapenem-resistant K. pneumoniae strains, our research revealed a polyclonal dissemination characteristic of CR K. oxytoca complex in China. S1-nuclease PFGE and Southern blot experiment showed that carbapenemase genes were encoded in plasmids of different sizes. Two bla NDM -harboring plasmids were subsequently sequenced, and were characterized to be IncX3 and IncC incompatibility groups, respectively. This is the first multi-center study of CR K. oxytoca complex in China, which improved our understanding of the prevalence and antimicrobial resistance characteristics of CR K. oxytoca complex in China., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Wan, Yang, Yu, Wang, Jia, Huang, Qu, Shan, Tang, Chen and Du.)

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Carbapenem non-susceptible Acinetobacter baumannii (CNSAB) is an important pathogen that causes nosocomial bacteremia among critically ill patients worldwide. The magnitude of antibiotic resistance of A. baumanii in Indonesia is expected to be significant; however, the data available are limited. The aim of this study was to analyze the genetic profiles of CNSAB isolates from patients with bacteremia in Indonesia. CNSAB isolates from blood cultures of bacteremia patients in 12 hospitals in Indonesia were included. The blood cultures were conducted using the BacT/Alert or BACTEC automated system. The CNSAB were identified with either Vitek 2 system or Phoenix platform followed by a confirmation test using a multiplex polymerase chain reaction (PCR) assay, targeting the specific gyrB gene. The carbapenemase genes were detected by multiplex PCR. In total, 110 CNSAB isolates were collected and were mostly resistant to nearly all antibiotic classes. The majority of CNSAB isolates were susceptible to tigecycline and trimethoprim-sulfamethoxazole (TMP-SMX), 45.5% and 38.2%, respectively. The blaOXA-51-like gene was identified in all CNSAB isolates. Out of the total, 83.6% of CNSAB isolates had blaOXA-23-like gene, 37.3% blaOXA-24-like gene, 4.5% blaNDM-1 gene, 0.9% blaIMP-1 gene, and 0.9% blaVIM gene. No blaOXA-48-like gene was identified. The blaOXA-23-like gene was the predominant gene in all except two hospitals. The presence of the blaOXA-24-like gene was associated with resistance to tigecycline, amikacin, TMP-SMX and cefoperazone-sulbactam, while blaOXA-23-like gene was associated with resistance to TMP-SMX and cefoperazone-sulbactam. In conclusion, the blaOXA-23-like gene was the predominant gene among CNSAB isolates throughout Indonesia. A continuous national surveillance system needs to be established to further monitor the genetic profiles of CNSAB in Indonesia. [ABSTRACT FROM AUTHOR]

Objectives: The prevalence of carbapenem-resistant Enterobacterales (CRE) has increased rapidly worldwide in the last two decades. CRE infection poses a huge challenge for today's clinical therapy. Rapid and accurate detection of clinical CRE isolates can avoid inappropriate antimicrobial treatment and reduce mortality. However, existing detection methods are either time consuming, expensive or inaccurate, making them unable to fully meet clinical demands. In this study, the HB&L system was designed to distinguish CRE from carbapenem-susceptible Enterobacterales (CSE), as it can accelerate the growth of bacteria, detect both carbapenemase-producing CRE (CP-CRE) and non-CP-CRE isolates in real time, and provide time-kill curves., Methods: The broth microdilution method and PCR and sequencing were used as the reference methods to identify CRE and carbapenemase-producing Enterobacterales (CPE) isolates, respectively. Three methods for detecting CRE isolates, including the Carba NP test, modified carbapenem inactivation method (mCIM) and HB&L system, were evaluated., Results: The accuracy of the HB&L system was extremely high with 100% sensitivity and 96.0% specificity at only 6 h of culture time for detecting CRE. Time-kill curves may provide information on effective treatment options for clinicians. This system is superior to the mCIM (20-24 h detection time; 90.6% sensitivity and 96.6% specificity) and Carba NP test (2 h detection time; 85.2% sensitivity and 98.4% specificity), which are only designed to detect CP-CRE., Conclusion: The HB&L system is promising for wide application for detection of clinical CRE in hospitals., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Carbapenemase-producing Alcaligenes species has been described in only few studies, with none so far from the African continent. Here, we report the whole genome sequence of P e analcaligenes suwonensis bearing bla VIM-5 metallo-β-lactamase and first detection of carbapenemase producing Alcaligenes faecalis isolated from patients attending tertiary healthcare facilities in Nigeria. The isolates were identified by MALDI-TOF Mass Spectrometry. Antibiotic susceptibility assay, modified Carba NP test and genomic investigation revealed that two isolates of Alcaligenes faecalis and an isolate of Paenalcaligenes suwonensis harboured bla VIM-5 gene. The genome sequence analysis of the P. suwonensis 191B isolate, responsible for acute gastroenteritis, reveal the presence of 18 antibiotic resistance genes coding for resistance to five different classes of antibiotics. Three of the genes (bla OXA-368 , bla CARB-4 and bla VIM-5) codes for resistance to β-lactam antibiotics. To our best knowledge, we describe here the first genome sequence of P. suwonensis species and the first detection of class B carbapenemase bla VIM-5 in a clinical isolate of P. suwonensis species and Alcaligenes faecalis in Nigeria. The finding of this study is of concern, as lateral dissemination of the genes into clinically important Gram-negative pathogens is highly likely. • Molecular characterization of clinical multidrug resistant isolates of Alcaligenes species from Sokoto hospital, Nigeria. • First description of Paenalcaligenes suwonensis strain bearing bla VIM-5 carbapenemase, responsible for acute gastroenteritis. • Description of first whole-genome sequences of Paenalcaligenes suwonensis species and its full resistome. [ABSTRACT FROM AUTHOR]

Background/purpose: The purpose of this study is to investigate the predominant clones of carbapenem-resistant Acinetobacter baumannii (CRAB) in our hospital in Taiwan by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) technique., Methods: We collected 108 non-duplicate A. baumannii clinical blood isolates from January 2012 to December 2013 in MacKay Memorial Hospital. PFGE and MLST were used for typing the A. baumannii isolates and for investigation of the predominant clones. Bacteria isolates were screened by polymerase chain reaction for the presence of the carbapenemase-encoding genes., Results: All 108 isolates were classified as 33 pulsotypes by PFGE. The predominant clones were pulsotype 10 (12.04%) in 2012 and pulsotype 8 (16.67%) in 2013, respectively. The 31 predominant pulsotype isolates were typed by MLST, and ST787 (54.84%) and ST455 (45.16%) were identified. All isolates carried bla OXA-51-like genes, and bla OXA-23-like genes was founded in 101 isolates (93.52%). Other identified resistance genes included bla OXA-24-like and bla OXA-IMP ., Conclusion: To the best of our knowledge, this study is the first to describe the microbiological characteristics of CRAB ST787, which carried high genetic resistance to carbapenem, but remained susceptible to colistin. CRAB ST787 was the predominant clone in our hospital in the study period., (Copyright © 2017. Published by Elsevier B.V.)

We report on the role of Acinetobacter radioresistens in a case of pneumonia in an elderly patient and describe the challenge of correct identification of this species. A tracheobronchial culture taken from a patient in a Bulgarian hospital yielded a pure culture of Gram-negative, lactose-non-fermenting bacilli on MacConkey agar. Genus and species identification was performed by biochemical tests and sequencing of the rpoB gene. Antimicrobial susceptibility testing and screening for blaOXA-like carbapenemase genes was done using microbroth dilution and PCR and sequencing, respectively. The bacillus growing on MacConkey agar was initially identified by biochemical tests as Acinetobacter baumannii complex. Sequencing of the rpoB gene finally identified A. radioresistens. The strain harboured the carbapenemase gene blaOXA-23 without insertion sequences upstream of this gene and was susceptible to imipenem and meropenem. In conclusion, detection of A. radioresistens remains a challenge for routine laboratory diagnostics without performance of molecular identification methods. Although A. radioresistens can be a causative agent of opportunistic infections, in the present case its involvement in the development of pneumonia is doubtful., (Copyright © 2015 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.)