Application of LAMP assay for detection of carbapenem-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex in ICU admitted sepsis patients: A rapid and cost-effective diagnostic tool.

Carbapenem-resistant significant members of Acinetobacter calcoaceticus-Acinetobacter baumannii (CR-SM-ACB) complex have emerged as an important cause of sepsis, especially in ICUs. This study demonstrates the application of loop-mediated-isothermal-amplification (LAMP) assay for detection of CR-SM-ACB-complex from patients with sepsis. Whole-blood and culture-broths(CB) collected from patients with culture-positive sepsis were subjected to LAMP and compared with PCR, and RealAmp. Vitek-2 system and conventional PCR results were used as confirmatory references. The sensitivity and specificity of LAMP(97 % & 100 %) and RealAmp(100 % & 100 %) for detection of CR-SM-ACB-complex from CB were better than PCR(87 % & 100 %). Diagnostic accuracy of LAMP, RealAmp, and PCR for detection of SM-ACB-complex from CB was 98.5 %, 100 %, and 88.5 % respectively. Turnaround time of Culture, LAMP, PCR, and RealAmp was 28-53, 6-20, 9-23, and 6-20hours, respectively. LAMP is a simple, inexpensive tool that can be applied directly to positive CB and may be customized to detect emerging pathogens and locally-prevalent resistance genes and to optimize antimicrobial use.

Healthcare-associated carbapenem-resistant Klebsiella pneumoniae infections are associated with higher mortality compared to carbapenem-susceptible K. pneumoniae infections in the intensive care unit: a retrospective cohort study.

BACKGROUND: Klebsiella pneumoniae (KP) is an opportunistic pathogen causing severe pneumonia and sepsis. Carbapenem-resistant KP (CRKP) has become a major pathogen in many centres. AIM: To investigate the association between carbapenem resistance and the mortality rate, length of stay, and hospital cost in patients with Klebsiella pneumoniae infection. METHODS: The retrospective cohort study was conducted in the intensive care units of a large teaching tertiary hospital in southwest China between January 1st, 2020 and December 31st, 2022. To examine the impact of carbapenem resistance on mortality rates and economic burden, multivariate Cox regression and generalized linear models were constructed. FINDINGS: The study included 282 adult patients with KP infection (135 CSKP; 147 CRKP). CRKP-infected patients demonstrated higher mortality risk (unadjusted hazard ratio (aHR): 1.980; 95% confidence interval (CI): 1.206-3.248; P = 0.007; aHR: 1.767; 95% CI: 1.038-3.005; P = 0.036) compared to CSKP-infected patients. Stratified analysis, according to type of KP infection, revealed that patients with healthcare-associated CRKP infection had a significantly higher mortality risk compared to those with CSKP infection (log-rank P = 0.015). Patients with CRKP infection had longer hospital stays than those infected with CSKP (adjusted mean: 38.74 vs 29.71 days; P = 0.003), and hospital-related expenses were notably higher among CRKP patients than CSKP patients (adjusted cost: £40,126.73 vs 25,713.74; P < 0.001). CONCLUSION: CRKP infections increase mortality rates, prolong hospital stays, and raise healthcare costs. Healthcare facilities should adopt targeted strategies, including curtailing pre-infection hospitalization periods and managing medications more judiciously.

Antibiotic management programme in a tertiary intensive care unit: effects of a carbapenem-restricted period on clinical and laboratory parameters and costs of infections.

BACKGROUND: Carbapenems are antibiotics used for serious infections. The consumption of carbapenems has increased worldwide due to increasing microbial resistance. AIM: To investigate the effects of a carbapenem-restricted antimicrobial stewardship programme (ASP) on changes in the resistance profiles of infectious agents, the amount of antibiotics used, length of stay in the intensive care unit (ICU), mortality, and costs. METHODS: Patients hospitalized in ICU between July 1st, 2020 and May 1st, 2021 were divided into two periods: the carbapenem-non-restricted period (CNRP); and the carbapenem-restricted period (CRP) in which alternative antibiotics to carbapenems were preferred during infection. The defined daily dose (DDD) per 100 patient-day methodology was used to calculate the antibiotic consumption. FINDINGS: Of the 572 patients included in the study, 62.2% were male, and mean age was 70.5 years. In the blood culture the most frequently Gram-negative agent was Acinetobacter baumannii (25%). A. baumannii bloodstream infections with multidrug-resistant and extensively drug resistant micro-organisms were significantly different between the two periods (CNRP: 95.6% (N = 22), CRP: 66.6% (N = 8); P = 0.04). There was a gradual decrease in the incidence density and rate of nosocomial infection (P = 0.06), and a significant decrease in meropenem consumption between the two periods (CNRP vs CRP: 21.19 vs 6.37 DDD per 100 patient-days respectively; P = 0.007). ASP yielded US$8,600 of antibiotic cost savings and a total of 14% patient cost savings (P < 0.05) per patient. CONCLUSION: Combining an effective ASP with a comprehensive infection control programme may mitigate the emergence of antimicrobial-resistant bacteria.

Assessment of in vitro colistin susceptibility of carbapenem-resistant clinical Gram-negative bacterial isolates using four commercially available systems & Whole-genome sequencing: A diagnostic accuracy study.

AIM: To analyze the diagnostic utility of commercially available platforms and Whole-genome sequencing (WGS) for accurate determination of colistin susceptibility test results. MATERIAL & METHODS: An exploratory diagnostic accuracy study was conducted in which sixty carbapenem-resistant Gram-negative bacteria were subjected to identification and AST using MALDI-TOF MS & MicroScan walkaway 96 Plus. Additional AST was performed using the BD Phoenix system and Mikrolatest colistin kit. The test isolates were subjected to Vitek-2 and WGS at CRL, Bengaluru. RESULTS: There was no statistically significant agreement between the colistin susceptibility results obtained by WGS, with those of commercial phenotypic platforms. The MicroScan 96 Plus had the highest sensitivity (31 %) & NPV (77 %), and the BD Phoenix system had the highest specificity (97 %) and PPV (50 %), respectively, for determining colistin resistance. CONCLUSION: The utility of WGS as a tool in AMR surveillance and validation of phenotypic AST methods should be explored further.

Disease burden of bacteraemia with extended-spectrum beta-lactamase-producing and carbapenem-resistant Enterobacterales in Korea.

BACKGROUND: Despite the significant impact of multi-drug-resistant bacteraemia, especially extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) and carbapenem-resistant Enterobacterales (CRE), the burden of disease has not been investigated thoroughly. AIM: To evaluate the clinical outcomes and socio-economic burden of ESBL-E and CRE bacteraemia nationwide in the Republic of Korea. METHODS: A search was undertaken for all cases of ESBL-E and CRE bacteraemia and matched controls in 10 hospitals in the Republic of Korea over 6 months. Patients with ESBL-E or CRE bacteraemia were classified as the R group, and matched controls with antibiotic-susceptible bacteraemia and without infection were classified as the S and N groups, respectively. Patients' clinical data were collected, and the economic burden was estimated based on medical expenses, loss of productivity and total costs. FINDINGS: In total, 795 patients were identified, including 265 patients with ESBL-E or CRE bacteraemia and their matched controls. The mean total length of stay for patients with ESBL-E and CRE in the R group was 1.53 and 1.90 times that of patients in the S group, respectively. The 90-day mortality rates for ESBL-E in the R and S groups were 12.1% and 5.6%, respectively, and the corresponding figures for CRE were 28.6% and 12.0%. There were significant differences in the total costs between the R, S and N groups for both ESBL-E and CRE (ESBL-E: $11,151 vs $8712 vs $6063, P=0.004; CRE: $40,464 vs $8748 vs $7279, P=0.024). CONCLUSION: The clinical and economic burden imposed by ESBL-E or CRE bacteraemia was extremely high. These findings suggest that efforts to control resistant bacteraemia are necessary to reduce this burden.

Activity fingerprinting of AMR ß-lactamase towards a fast and accurate diagnosis.

Antibiotic resistance has become a serious threat to global public health and economic development. Rapid and accurate identification of a patient status for antimicrobial resistance (AMR) are urgently needed in clinical diagnosis. Here we describe the development of an assay method for activity fingerprinting of AMR ß-lactamases using panels of 7 ß-lactam antibiotics in 35 min. New Deli Metallo ß-lactamase-1 (NDM-1) and penicillinase were demonstrated as two different classes of ß-lactamases. The panel consisted of three classes of antibiotics, including: penicillins (penicillin G, piperacillin), cephalosporins (cefepime, ceftriaxone, cefazolin) and carbapenems (meropenem and imipenem). The assay employed a scheme combines the catalytic reaction of AMR ß-lactamases on antibiotic substrates with a flow-injected thermometric biosensor that allows the direct detection of the heat generated from the enzymatic catalysis, and eliminates the need for custom substrates and multiple detection schemes. In order to differentiate classes of ß-lactamases, characterization of the enzyme activity under different catalytic condition, such as, buffer composition, ion strength and pH were investigated. This assay could provide a tool for fast diagnosis of patient AMR status which makes possible for the future accurate treatment with selected antibiotics.

Characterization and fitness cost analysis of two plasmids carrying different subtypes of blaNDM in aquaculture farming.

In recent years, the blaNDM gene, which mediate resistance to carbapenems, has disseminated all over the world, and has also been detected in animals. Understanding the dissemination and accumulation of antibiotic resistance genes (ARGs) in a human-impacted environment is essential to solve the food safety problems caused by antibiotics. In this study, two strains of carbapenem bacteria carrying blaNDM were screened from 244 strains isolated from two T. sinensis farms in Zhejiang province, China. After their plasmids were isolated and sequenced, their structure and gene environment were analyzed and the mechanism of blaNDM gene transfer was explored. The study measured the fitness cost of plasmids carrying different blaNDM subtypes by four biological characteristics experiments. The results showed that the fitness cost of IncC plasmid carrying blaNDM-1 was higher than that of IncX3 plasmid carrying blaNDM-5. Furthermore, the real-time PCR showed that the decrease of transcription level of fitness-related genes lead to the different fitness cost of plasmids carrying different blaNDM subtypes. Fitness of many blaNDM-harboring plasmids enhanced the further dissemination of this gene and increase the risk of blaNDM gene spreading in aquatic environment, and thus further investigation of carbapenem-resistant bacterias among food animals are in urgent need.

Assessment of mortality-related risk factors and effective antimicrobial regimens for treatment of bloodstream infections caused by carbapenem-resistant Pseudomonas aeruginosa in patients with hematological diseases.

Background: Infections caused by carbapenem-resistant Pseudomonas aeruginosa (CRPA) are related to higher mortality. The objective of this study was to explore clinical outcomes of CRPA bacteremia, identify risk factors and also, compare the efficacy of traditional and novel antibiotic regimens. Methods: This retrospective study was conducted at a blood diseases hospital in China. The study included hematological patients who were diagnosed with CRPA bacteremia between January 2014 and August 2022. The primary endpoint was all-cause mortality at day 30. Secondary endpoints included 7-day and 30-day clinical cure. Multivariable Cox regression analysis was employed to identify mortality-related risk factors. Results: 100 patients infected with CRPA bacteremia were included and 29 patients accepted allogenic-hematopoietic stem cell transplantation. 24 received ceftazidime-avibactam (CAZ-AVI)-based therapy and 76 received other traditional antibiotics. 30-day mortality was 21.0%. Multivariable cox regression analysis showed neutropenia >7 days after bloodstream infections (BSI) (P=0.030, HR: 4.068, 95%CI: 1.146~14.434), higher Pitt bacteremia score (P<0.001, HR:1.824, 95%CI: 1.322~2.517), higher Charlson comorbidity index (P=0.01, HR: 1.613, 95%CI: 1.124~2.315) and bacteremia due to multidrug-resistant Pseudomonas aeruginosa (MDR-PA) (P=0.024, HR:3.086, 95%CI: 1.163~8.197) were identified as independent risk factors of 30-day mortality. After controlling for confounders, an additional multivariable cox regression analysis revealed definitive regimens containing CAZ-AVI were associated with lower mortality in CRPA bacteremia (P=0.016, HR: 0.150, 95%CI: 0.032~0.702), as well as in MDR-PA bacteremia (P=0.019, HR: 0.119, 95%CI: 0.020~0.709). Conclusions: For patients with hematological diseases and CRPA bacteremia, 30-day mortality rate was 21.0% (21/100). Neutropenia >7 days after BSI, higher Pitt bacteremia score, higher Charlson comorbidity index and bacteremia due to MDR-PA increased 30-day mortality. CAZ-AVI-based regimens were effective alternatives for bacteremia due to CRPA or MDR-PA.

Therapeutic effect and anti-biofilm ability assessment of a novel phage, phiPA1-3, against carbapenem-resistant Pseudomonas aeruginosa.

Multiple drug-resistant (MDR) Pseudomonas aeruginosa commonly causes severe hospital-acquired infections. The gradual emergence of carbapenem-resistant P. aeruginosa has recently gained attention. A wide array of P. aeruginosa-mediated pathogenic mechanisms, including its biofilm-forming ability, limits the use of effective antimicrobial treatments against it. In the present study, we isolated and characterized the phenotypic, biological, and genomic characteristics of a bacteriophage, vB_PaP_phiPA1-3 (phiPA1-3). Biofilm eradication and phage rescue from bacterial infections were assessed to demonstrate the efficacy of the application potential. Host range spectrum analysis revealed that phiPA1-3 is a moderate host range phage that infects 20% of the clinically isolated strains of P. aeruginosa tested, including carbapenem-resistant P. aeruginosa (CRPA). The phage exhibited stability at pH 7.0 and 9.0, with significantly reduced viability below pH 5.0 and beyond pH 9.0. phiPA1-3 is a lytic phage with a burst size of 619 plaque-forming units/infected cell at 37 °C and can effectively lyse bacteria in a multiplicity of infection-dependent manner. The genome size of phiPA1-3 was found to be 73,402 bp, with a G+C content of 54.7%, containing 93 open reading frames, of which 62 were annotated as hypothetical proteins and the remaining 31 had known functions. The phage possesses several proteins similar to those found in N4-like phages, including three types of RNA polymerases. This study concluded that phiPA1-3 belongs to the N4-like Schitoviridae family, can potentially eradicate P. aeruginosa biofilms, and thus, serve as a valuable tool for controlling CRPA infections.

Estimating the effect of increasing ambient temperature on antimicrobial resistance in China: A nationwide ecological study with the difference-in-differences approach.

Antimicrobial resistance (AMR) and the possible consequences of rising ambient temperatures brought on by global warming have been extensively discussed. However, the epidemiological evidence on the effects of temperature on AMR is rare and little is known about the role of socioeconomic inequities. This ecological study obtained 31 provinces AMR data of Escherichia Coli (E. coli) from the China Antimicrobial Resistance Surveillance System (CARSS) over the period from 2014 to 2020, which were linked to the meteorological and socioeconomic data published in the China Statistical Yearbook. Modified difference-in-differences (DID) analyses were performed to estimate the effect of ambient temperature on AMR of E. coli to third-generation cephalosporins (ceftriaxone and cefotaxime), carbapenems, and quinolones, adjusting for variations in meteorological and socioeconomic factors. We estimated that every 1 °C increase in average ambient temperature was associated with 2.71 % (95 % confidence interval [CI]: 1.20-4.24), 32.92 % (95 % CI: 15.62-52.81), and 1.81 % (95 % CI: 0.47-3.16) increase in the prevalence of E. coli resistance to third-generation cephalosporins (ceftriaxone and cefotaxime), carbapenems and quinolones, respectively. The link was more profound in the regions with lower temperature and a median level of average humidity, and the regions with lower income, lower expenditure (in economics), lower health resources, and lower hospital admissions. Neither the replacement of the temperature variable nor the alternative approaches for confounding adjustment changed the positive association between ambient temperature and AMR. In general, there exists a positive association between ambient temperature and AMR, although the strength of such an association varies by socioeconomic and health services factors. The association is possibly nonlinear, especially for E. coli resistance to third-generation cephalosporins. The findings suggest that AMR control programs should explicitly incorporate weather patterns to increase their effectiveness.

Comparative evaluation of phenotypic and genotypic methods for the rapid and cost-effective detection of carbapenemases in extensively drug resistant Klebsiella pneumoniae.

PURPOSE: Carbapenemases are the enzymes that can hydrolyze carbapenems and other ß-lactam antibiotics. These enzymes confer resistance to multiple antibiotics and act as a stumbling block in the treatment of infections caused by gram-negative bacteria. Therefore, rapid and specific detection of these enzymes is crucial for deciding the course of treatment and better clinical outcomes. MATERIAL AND METHODS: This study was conducted to compare various phenotypic and PCR based methods for the detection of carbapenemases in carbapenem- and colistin-resistant Klebsiella pneumoniae. One hundred clinical isolates of extensively resistant Klebsiella pneumoniae were included in the study. Phenotypic detection for carbapenemases was performed by Rapidec® Carba NP (Biomerieux), modified carbapenem inactivation method (mCIM), imipenem-ethylenediaminetetraacetic acid disk synergy (EDS), double disk synergy test using mercaptopropionic acid (DDST-MPA), and combined disk method (CD) and for colistin by microbroth dilution method. Genotypic detection for carbapenemases and colistin resistance was performed by targeted PCR. RESULTS: The sensitivity of Carba NP test and mCIM were positive in 95% and 96% respectively and specificity was 100% for both methods. The sensitivity of EDS, DDST-MPA, and CD were 55.6%, 88.9% and 54.5% respectively. Among the carbapenem resistance genes, blaOXA-48 (82%) genes were the most prevalent. Among metallo-beta lactamases, blaVIM (56%) was most common followed by blaNDM (54%) and blaIMP (20%). The mcr-1 gene for colistin resistance was not detected in any isolate. CONCLUSION: Among the five phenotypic assays analyzed, the mCIM is the most simple, inexpensive, accurate and reproducible method for carbapenemase detection in Klebsiella pneumoniae. The DDST-MPA test provides the best sensitivity for the detection of carbapenemases, although specificity is low. These tests, when applied in a clinical laboratory and assessed by the microbiologist, can help in guiding the course of treatment.

Klebsiella Species and Enterobacter cloacae Isolates Harboring blaOXA-181 and blaOXA-48: Resistome, Fitness Cost, and Plasmid Stability.

IncX3 and IncL plasmids have been named as catalysts advancing dissemination of blaOXA-181 and blaOXA-48 genes. However, their impact on the performance of host cells is vastly understudied. Genetic characteristics of blaOXA-48- and blaOXA-181-containing Klebsiella pneumoniae (EFN299), Klebsiella quasipneumoniae (EFN262), and Enterobacter cloacae (EFN743) isolated from clinical samples in a Ghanaian hospital were investigated by whole-genome sequencing. Transfer of plasmids by conjugation and electroporation, plasmid stability, fitness cost, and genetic context of blaOXA-48, blaOXA-181, and blaDHA-1 were assessed. blaOXA-181 was carried on two IncX3 plasmids, an intact 51.5-kb IncX3 plasmid (p262-OXA-181) and a 45.3-kb IncX3 plasmid (p743-OXA-181) without replication protein sequence. The fluoroquinolone-resistant gene qnrS1 region was also excised, and unlike in p262-OXA-181, the blaOXA-181 drug-resistant region was not found on a composite transposon. blaOXA-48 was carried on a 74.6-kb conjugative IncL plasmid with unknown ~10.9-kb sequence insertion. This IncL plasmid proved to be highly transferable, with a conjugation efficiency of 1.8 × 10-2. blaDHA-1 was present on an untypeable 22.2 kb genetic structure. Plasmid stability test revealed plasmid loss rate between 4.3% and 12.4%. The results also demonstrated that carriage of IncX3-blaOXA-181 or IncL-blaOXA-48 plasmids was not associated with any fitness defect, but rather an enhanced competitive ability of host cells. This study underscores the significant contribution of IncX3 and IncL plasmids in the dissemination of resistance genes and their efficient transfer calls for regular monitoring to control the expansion of resistant strains. IMPORTANCE The growing rate of antibiotic resistance is an important global health threat. This threat is exacerbated by the lack of safe and potent alternatives to carbapenems in addition to the slow developmental process of newer and effective antibiotics. Infections by carbapenem-resistant Gram-negative bacteria are becoming almost untreatable, leading to poor clinical outcomes and high mortality rates. OXA-48-like carbapenemases are one of the most widespread carbapenemases accounting for resistance among Enterobacteriaecae. We characterized OXA-48- and OXA-181-producing Enterobacteriaecae to gain insights into the genetic basis and mechanism of resistance to carbapenems. Findings from the study showed that the genes encoding these enzymes were carried on highly transmissible plasmids, one of which had sequences absent in other similar plasmids. This implies that mobile genetic elements are important players in the dissemination of resistance genes. Further characterization of this plasmid is warranted to determine the role of this sequence in the spread of resistance genes.

Carbapenem-resistant Pseudomonas aeruginosa: an assessment of frequency of isolation from ICU versus non-ICU, phenotypic and genotypic profiles in a multinational population of hospitalized patients.

BACKGROUND: Historically, multi-drug resistant organisms have been associated with the ICU setting. The present study sought to define the frequency of isolation from ICU versus non-ICU, phenotypic and genotypic profiles of carbapenem-resistant Pseudomonas aeruginosa (CR-PA) from a global cohort. METHODS: Multicenter surveillance study (17 centers from 12 countries) including 672 CR-PA isolates from 2019 to 2021. Phenotypic carbapenemase testing was assessed. Genotypic carbapenemase testing was conducted (CarbaR and CarbaR NxG) to detect ß-lactamases. Broth microdilution MICs were established for ceftazidime, cefepime, ceftolozane/tazobactam, and ceftazidime/avibactam. RESULTS: 59% of CR-PA were isolated from patients outside the ICU. The most common source in ICU and non-ICU patients was respiratory (55% and 30%, respectively). In the ICU, 35% of isolates were phenotypically carbapenemase-positive versus 29% for non-ICU. VIM was the most common carbapenemase (54% and 44%, respectively) followed by GES (27% and 28%, respectively). Susceptibility to ceftazidime or cefepime were relatively low in ICU (39% and 41% of isolates, respectively) and non-ICU (47% and 52% of isolates, respectively). Ceftolozane/tazobactam and ceftazidime/avibactam were more active with 56% and 66% of isolates susceptible in the ICU while 65% and 76% in non-ICU, respectively. When carbapenemase-negative, 86% and 88% of ICU isolates were susceptible to ceftolozane/tazobactam and ceftazidime/avibactam. Similarly, in the carbapenemase-negative, non-ICU isolates 88% and 92% of isolates were susceptible, respectively. CONCLUSION: Although multidrug resistant pathogens are often regarded as a challenge in the ICU population, the majority of CR-PA were isolated from non-ICU patients. Implementing phenotypic/genotypic testing will assist in guiding treatment. Carbapenem-resistance in P. aeruginosa should be regarded as a surrogate for MDR and this phenotype is increasingly prevalent outside the ICU.

Genome Assessment of Carbapenem- and Colistin-Resistant Escherichia coli from Patients in a Sentinel Hospital in China.

Antimicrobial-resistant (AMR) pathogens are a significant threat to public health worldwide. However, the primary carrier of AMR genes, particularly against last-resort antibiotics, is still only partially studied in Chinese hospitals. In a sentinel hospital in China, we collected 157 E. coli strains from patients between January and July 2021. One blaNDM-1-, nine blaNDM-5-, and one mcr-1-positive E. coli recovered from inpatients were identified as resistant to meropenem and colistin. There are 37 virulence genes discovered in the 11 strains, including astA in strain EC21Z-147 (O128: H4), which belongs to the enteroaggregative E. coli (EAEC). The blaNDM gene is distributed into distinct ST types, including ST48, ST616, ST410, ST711, and ST2003, while the mcr-1 gene was identified in ST117. The conjugative plasmids IncX3, IncI1-I, and IncI2 mediated the blaNDM-5 and mcr-1 genes detected among inpatients. Notably, the youngest age at which mcr-1-positive E. coli has been reported was at one day old, in a child in which the strain is closely related to strains with animal origins. Hospitals are major environments for the spread and dissemination of critical virulence and AMR genes, which requires active monitoring systems at the genome level to surveil the spread of virulence and AMR.

In vivo acquisition of blaKPC-2 with low biological cost in blaAFM-1-harboring ST463 hypervirulent Pseudomonas aeruginosa from a patient with hematologic malignancy.

OBJECTIVES: Klebsiella pneumoniae carbapenemase (KPC)-producing sequence type (ST) 463 Pseudomonas aeruginosa are increasingly prevalent in China. This study aims to investigate how blaKPC-2 is acquired in ST463 P. aeruginosa during antimicrobial therapy. METHODS: Two extensively drug-resistant P. aeruginosa strains, B1122 and U1121, were respectively isolated from blood and urine of a patient during carbapenem therapy. Whole-genome sequences were obtained, and minimum inhibitory concentrations (MICs) were determined. Plasmid transferability and stability were examined. Bacterial growth kinetics, biofilm formation, and virulence level was assessed. RESULTS: U1121 and B1122 were only susceptible to amikacin and intermediately susceptible to colistin. They were isogenic ST463 P. aeruginosa strains and shared the same chromosome-encoded resistance genes, including blaAFM-1. This is the first report of chromosomal integration of blaAFM-1 in P. aeruginosa mediated by ISCR29. pU1121 and pB1122, which shared almost identical backbone, were the sole plasmids in U1121 and B1122, respectively, differing by an insertion region containing two copies of blaKPC-2 genes observed on pU1121. Sequence alignment revealed that pU1121 might evolve in vivo from pB1122 via IS26-mediated continuous genetic rearrangement in response to selective challenge from carbapenem. pU1121 was not self-transmissible and could be stably maintained in the host in the absence of antibiotic. Both U1121 and B1122 were hypervirulent, and no differences on virulence were recorded between them. However, U1121 exhibited significant impaired growth in comparison with B1122. CONCLUSION: ST463 P. aeruginosa can capture blaKPC-2 through horizontal transfer of insertion sequence under antibiotic selection pressure, which does decrease the fitness but does not impair the virulence of the ancestor.

Assessment of ß-lactams and Carbapenems Antimicrobials Resistance in Klebsiella Oxytoca Isolated from Patients with Urinary Tract Infections in Najaf, Iraq.

Antimicrobial resistance is becoming an arising global issue. Until recent years, more than 50% of commercially available antibiotics were ß-lactam. Pathogenic bacteria which are resistant to antibiotics include all ß-lactams except for cephamycin and carbapenems. This study aimed to evaluate some ß-lactams and carbapenems antimicrobials resistance in Klebsiella oxytoca. In total, 177 urinary tract infection samples were collected for the purposes of the study. Isolates were identified using morphological features and routine biochemical testing. All isolates were tested for susceptibility to 11 antibiotics using the usual disc diffusion method. The result showed that 155 (87.57%) and 20 (11.29%) out of 177 collected urine samples were gram-negative bacterial isolates and gram-positive bacterial isolates, respectively. The findings also showed that there were two samples (1.12 %) with no growth. The results proved no susceptibility to Ampicillin, Cloxacillin, Ceftazidime, Penicillin, Piperacillin with a resistance rate of 100%.

Global antimicrobial resistance: a system-wide comprehensive investigation using the Global One Health Index.

BACKGROUND: Antimicrobial resistance (AMR) is one of the top ten global public health challenges. However, given the lack of a comprehensive assessment of worldwide AMR status, our objective is to develop a One Health-based system-wide evaluation tool on global AMR. METHODS: We have further developed the three-hierarchical Global One Health Index (GOHI)-AMR indicator scheme, which consists of five key indicators, 17 indicators, and 49 sub-indicators, by incorporating 146 countries' data from diverse authoritative databases, including WHO's Global Antimicrobial Resistance and Use Surveillance System (GLASS) and the European CDC. We investigated the overall- or sub-rankings of GOHI-AMR at the international/regional/national levels for data preprocessing and score calculation utilizing the existing GOHI methodology. Additionally, a correlation analysis was conducted between the GOHI-AMR and other socioeconomic factors. RESULTS: The average GOHI-AMR score for 146 countries is 38.45. As expected, high-income countries (HICs) outperform the other three income groups on overall rankings and all five key indicators of GOHI-AMR, whereas low-income countries unexpectedly outperform upper-middle-income countries and lower-middle-income countries on the antibiotics-resistant key indicator (ARR) and ARR-subordinate indicators, including carbapenem-, ß-lactam-, and quinolone resistance, and even HICs on aminoglycoside resistance. There were no significant differences among the four groups on the environmental-monitoring indicator (P > 0.05). GOHI-AMR was positively correlated with gross domestic product, life expectancy, and AMR-related publications, but negatively with natural growth rate and chronic respiratory disease. In contrast to Cyprus, the remarkably lower prevalence of "ESKAPE pathogens" in high-scoring Sweden and Denmark highlights Europe's huge gaps. China and Russia outperformed the other three BRICS countries on all key indicators, particularly India's ARR and Brazil's AMR laboratory network and coordination capacity. Furthermore, significant internal disparities in carbapenem-resistant Klebsiella pneumoniae (CRKP) and methicillin-resistant Staphylococcus aureus (MRSA) prevalence were observed between China and the USA, with MRSA prevalence both gradually declining, whereas CRKP prevalence has been declining in the USA but increasing in China, consistent with higher carbapenems-related indicator' performance in USA. CONCLUSIONS: GOHI-AMR is the most comprehensive tool currently available for the assessment of AMR status worldwide. We discovered unique features impacting AMR in each country and offered precise recommendations to improve the capacity to tackle AMR in low-ranking countries.

Economic and clinical burden from carbapenem-resistant bacterial infections and factors contributing: a retrospective study using electronic medical records in Japan.

BACKGROUND: Antimicrobial resistance is a major threat to global health and the world economy. The economic burden of carbapenem-resistant infections has not previously been evaluated. We aimed to compare the potential economic burden and clinical outcomes between carbapenem-resistant infections and carbapenem-susceptible infections in Japan. METHODS: We conducted a retrospective cohort study using electronic medical records. Patients aged 15 years or older and with the diagnosis of pneumonia, urinary tract infection, biliary infection, and sepsis were included. Multivariable regression models with random effects were used to estimate the impact of carbapenem resistance on cost, length of hospital stay, and in-hospital mortality. RESULTS: Among the 9,517 patients, 86 (0.9%) had carbapenem-resistant (CR) infections. Compared to carbapenem-susceptible (CS) infections, the patients with the CR infections were significantly more likely to receive mechanical ventilation (37.2 vs. 21.2%, P-value = 0.003), antibiotics (88.4 vs. 63.0%, P-value < 0.001), and especially carbapenem (31.4 vs. 8.3%, P-value < 0.001), before the bacterial culture test positive. Significantly higher median costs were found for the CR infections than the CS infections in the categories of medications (3477 US dollars vs. 1609 US dollars), laboratory tests (2498 US dollars, vs. 1845 US dollars), and hospital stay (14,307 US dollars vs. 10,560 US dollars). In the multivariable regression analysis, the length of stay was 42.1% longer and the cost was 50.4% higher in the CR infections than in the CS infections. The risk of in-hospital mortality did not differ between the two groups (odds ratio 1.24, 95% CI 0.72-2.11), due to the small sample size. The result was robust with a similar trend in the analysis using the inverse probability treatment weighting method. CONCLUSIONS: Compared to carbapenem-susceptible infections, carbapenem-resistant infections were associated with a higher cost and a longer length of stay. Detailed cost analysis showed significant differences in the categories of medication, laboratory tests, and hospital stay. To our knowledge, this study is the first to assess the potential economic burden of carbapenem-resistant infections using a large hospital-based database.

Nosocomial transmission and rearrangement of large resistance-virulence hybrid plasmids between two bacteremic ST11 carbapenem-resistant hypervirulent Klebsiella pneumoniae strains with low fitness cost.

OBJECTIVES: To characterize nosocomial transmission and rearrangement of the resistance-virulence plasmid between two ST11-K64 carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) strains (JX-CR-hvKP-10 and JX-CR-hvKP-9) with low fitness. METHODS: Phenotypic tests were used to assess the virulence of JX-CR-hvKP-10 and JX-CR-hvKP-9. Whole-genome sequencing was used to analyze JX-CR-hvKP-10 and JX-CR-hvKP-9 chromosomes and plasmids. Fitness and conjugation experiments were also conducted using these two CR-hvKP isolates. RESULTS: Phenotypic tests indicated that both JX-CR-hvKP-10 and JX-CR-hvKP-9 were multidrug-resistant and hypervirulent K. pneumoniae. Whole-genome sequencing and clinical information demonstrated that the super large resistance-virulence fusion plasmid pJX10-1 formed precisely by the fusion of pJX9-1 and pJX9-2 via the nosocomial transmission. Interestingly pJX9-1 itself was also a classic resistance-virulence fusion plasmid by way of the blaKPC-carrying resistance plasmid and pLVPK-like virulence plasmid. Compared with classic K. pneumoniae ATCC700603, fitness analysis revealed no significant difference in growth was observed between JX-CR-hvKP-10 and JX-CR-hvKP-9. CONCLUSION: Nosocomial transmission and rearrangement of a blaKPC-harboring plasmid and a pLVPK-like virulence plasmid with a low fitness cost in ST11 K. pneumoniae enhances drug resistance and virulence simultaneously. Thus, active surveillance of this hybrid plasmid is needed to prevent these efficient resistance-virulence plasmids from disseminating in hospital settings.

Burden of illness in carbapenem-resistant Acinetobacter baumannii infections in US hospitals between 2014 and 2019.

BACKGROUND: Carbapenem-resistant (CR) Acinetobacter baumannii is a concerning pathogen in the USA and worldwide. METHODS: To assess the comparative burden of CR vs carbapenem-susceptible (CS) A. baumannii, this retrospective cohort study analyzed data from adult patients in 250 US hospitals from the Premier HealthCare Database (2014-2019). The outcomes analyzed included hospital length of stay (LOS), intensive care unit (ICU) utilization, discharge status, in-hospital mortality, readmission rates and hospital charges. Logistic regression was used for univariate and multivariable assessment of the independent relationship between relevant covariates, with a focus on CR status, and in-hospital mortality. RESULTS: 2047 Patients with CR and 3476 patients with CS A. baumannii infections were included. CR A. baumannii was more commonly isolated in respiratory tract infections (CR 40.7% and CS 27.0%, P < 0.01), whereas CS A. baumannii was more frequently associated with bloodstream infections (CS 16.7% and CR 8.6%, P < 0.01). Patients with CR A. baumannii infections had higher in-hospital (CR 16.4% vs CS 10.0%; P < 0.01) and 30-day (CR 32.2% vs CS 21.6%; P < 0.01) mortality compared to those with CS infections. After adjusting for age, sex, admission source, infection site, comorbidities, and treatment with in vitro active antibiotics within 72 h, carbapenem resistance was independently associated with increased mortality (adjusted odds ratio 1.42 [95% confidence interval 1.15; 1.75], P < 0.01). CR infections were also associated with increases in hospital length of stay (CR 11 days vs CS 9 days; P < 0.01), rate of intensive care unit utilization (CR 62.3% vs CS 45.1%; P < 0.01), rate of readmission with A. baumannii infections (CR 17.8% vs CS 4.0%; P < 0.01) and hospital charges. CONCLUSIONS: These data suggest that the burden of illness is significantly greater for patients with CR A. baumannii infections and are at higher risk of mortality compared with CS infections in US hospitals.