Infection control implications of heterogeneous resistance mechanisms in carbapenem-resistant Enterobacteriaceae (CRE)

In vitro activity of cefiderocol against European Enterobacterales, including isolates resistant to meropenem and recentβ-lactam/β-lactamase inhibitor combinations

Carbapenem-resistant Enterobacterales represent a major health threat and have few approved therapeutic options. Enterobacterales isolates were collected from hospitalized inpatients from 49 sites in six European countries (1 January-31 December 2020) and underwent susceptibility testing to cefiderocol and β-lactam/β-lactamase inhibitor combinations. Meropenem-resistant (MIC >8 mg/L) and cefiderocol-susceptible isolates were analyzed by PCR, and cefiderocol-‍resistant isolates by whole-genome sequencing, to identify resistance mechanisms. Overall, 1,909 isolates (including 970 Klebsiella spp., 382 Escherichia coli, and 244 Enterobacter spp.) were collected, commonly from bloodstream infections (43.6%). Cefiderocol susceptibility was higher than approved β-lactam/β-lactamase inhibitor combinations and largely comparable to cefepime-taniborbactam and aztreonam-avibactam against all Enterobacterales (98.1% vs 78.1%-‍97.4% and 98.7%-99.1%, respectively) and Enterobacterales resistant to meropenem (n = 148, including 125 Klebsiella spp.; 87.8% vs 0%-71.6% and 93.2%-98.6%, respectively), β-lactam/β-lactamase inhibitor combinations (66.7%-‍92.1% vs 0%-‍88.1% and 66.7%-97.9%, respectively), and to both meropenem and β-‌lactam/β-lactamase inhibitor combinations (61.9%-65.9% vs 0%-‍20.5% and 76.2%-97.7%, respectively). Susceptibilities to approved and developmental β-lactam/β-lactamase inhibitor combinations against cefiderocol-resistant Enterobacterales (n = 37) were 10.8%-‍56.8% and 78.4%-94.6%, respectively. Most meropenem-resistant Enterobacterales harbored Klebsiella pneumoniae carbapenemase (110/148) genes, although metallo-β-lactamase (35/148) and oxacillinase (OXA) carbapenemase (6/148) genes were less common; cefiderocol susceptibility was retained in β-lactamase producers, other than NDM, AmpC, and non-carbapenemase OXA producers. Most cefiderocol-resistant Enterobacterales had multiple resistance mechanisms, including ≥1 iron uptake-related mutation (37/37), carbapenemase gene (33/37), and ftsI mutation (24/37). The susceptibility to cefiderocol was higher than approved β-lac‌tam/β-lactamase inhibitor combinations against European Enterobacterales, including meropenem- and β-lactam/β-lactamase inhibitor combination-resistant isolates.

IMPORTANCE

This study collected a notably large number of Enterobacterales isolates from Europe, including meropenem- and β-lactam/β-lactamase inhibitor combination-resistant isolates against which the in vitro activities of cefiderocol and developmental β-lactam/β-lactamase inhibitor combinations were directly compared for the first time. The MIC breakpoint for high-dose meropenem was used to define meropenem resistance, so isolates that would remain meropenem resistant with doses clinically available to patients were included in the data. Susceptibility to cefiderocol, as a single active compound, was high against Enterobacterales and was higher than or comparable to available β-lactam/β-lactamase inhibitor combinations. These results provide insights into the treatment options for infections due to Enterobacterales with resistant phenotypes. Early susceptibility testing of cefiderocol in parallel with β-lactam/β-lactamase inhibitor combinations will allow patients to receive the most appropriate treatment option(s) available in a timely manner. This is particularly important when options are more limited, such as against metallo-β-lactamase-producing Enterobacterales.

Comparison of ERIC carbapenem-resistant Enterobacteriaceae test, BD Phoenix CPO detect panel, and NG-test CARBA 5 for the detection of main carbapenemase types of carbapenem-resistant Enterobacterales

BACKGROUND

This study aimed to assess the performance of three commercial panels, the ERIC Carbapenem-Resistant Enterobacteriaceae Test (ERIC CRE test), the NG-Test CARBA 5 (NG CARBA 5), and the BD Phoenix CPO Detect Panel (CPO panel), for the detection of main types of carbapenemases among carbapenem-resistant Enterobacterales (CRE).

METHODS

We collected 502 isolates of carbapenem-resistant Enterobacterales (CRE) demonstrating intermediate or resistant profiles to at least one carbapenem antibiotic (ertapenem, imipenem, meropenem, or doripenem). Carbapenemase genes and their specific types were identified through multiplex PCR and sequencing methods. Subsequently, the ERIC CRE test, CPO panel, and NG CARBA 5 assay were conducted on these isolates, and the results were compared with those obtained from multiplex PCR.

RESULTS

The results indicated that the ERIC CRE test exhibited an overall sensitivity and specificity of 98.1% and 93.6%, respectively, which were comparable to 99.1% and 90.6% for the NG CARBA 5. However, the CPO panel demonstrated a sensitivity of only 56.2% in identifying Ambler classes, exhibiting the poorest sensitivity for class A. Moreover, while the ERIC CRE test outperformed the NG CARBA 5 in identifying multi-gene isolates with multiple carbapenemase-encoding genes, the CPO panel failed to accurately classify these isolates.

CONCLUSIONS

Our findings support the utilization of the ERIC CRE test as one of the methods for detecting carbapenemases in clinical laboratories. Nonetheless, further optimization is imperative for the CPO panel to enhance its accuracy in determining carbapenemase classification and address limitations in detecting multi-gene isolates.

Coexistence of blaKPC-2 and blaNDM-1 in one IncHI5 plasmid confers transferable carbapenem resistance from a clinical isolate of Klebsiella michiganensis in China

OBJECTIVES

This study firstly identified an IncHI5 plasmid pK254-KPC_NDM co-carrying two different class carbapenemase genes blaKPC-2 and blaNDM-1 in Klebsiella michiganensis K254.

METHODS

The strain K254 was sequenced by high-throughput genome sequencing. A detailed genomic and phenotypic characterization of pK254-KPC_NDM was performed.

RESULTS

pK254-KPC_NDM displayed the conserve IncHI5 backbone and carried a resistant accessory region: Tn1696-related transposon Tn7414 containing blaKPC-2 and blaNDM-1. A sequence comparison was applied to a collection of four Tn1696-related transposons (Tn7414-Tn7417) harbouring carbapenemase genes. For all these four transposons, the blaNDM-1 was carried by Tn125 derivatives within three different mobile genetic elements. Tn7414 further acquired another carbapenemase gene, blaKPC-2, because of the integration of the local blaKPC-2 genetic environment from Tn6296, resulting in the high-level carbapenem resistance of K. michiganensis K254. The conjugal transfer and plasmid stability experiments confirmed that pK254-KPC_NDM could be transferred intercellularly and keep the stable vertical inheritance in different bacteria, which would contribute to the further dissemination of multiple carbapenemase genes and enhance the adaption and survival of K. michiganensis under complex and diverse antimicrobial selection pressures.

CONCLUSION

This study was the first to report the K. michiganensis isolate coharbouring blaKPC-2 and blaNDM-1 in the Tn1696-related transposon in IncHI5 plasmid. The emergence of novel transposons simultaneously carrying multiple carbapenemase genes might contribute to the further dissemination of high-level carbapenem resistance in the isolates of the hospital settings and pose new challenges for the treatment of nosocomial infection.

Antimicrobial Activities of Aztreonam-Avibactam and Comparator Agents against Enterobacterales Analyzed by ICU and Non-ICU Wards, Infection Sources, and Geographic Regions: ATLAS Program 2016-2020

Increasing antimicrobial resistance among multidrug-resistant (MDR), extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing Enterobacterales (CPE), in particular metallo-β-lactamase (MBL)-positive strains, has led to limited treatment options in these isolates. This study evaluated the activity of aztreonam-avibactam (ATM-AVI) and comparator antimicrobials against Enterobacterales isolates and key resistance phenotypes stratified by wards, infection sources and geographic regions as part of the ATLAS program between 2016 and 2020. Minimum inhibitory concentrations (MICs) were determined per Clinical and Laboratory Standards Institute (CLSI) guidelines. The susceptibility of antimicrobials were interpreted using CLSI and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. A tentative pharmacokinetic/pharmacodynamic breakpoint of 8 µg/mL was considered for ATM-AVI activity. ATM-AVI inhibited ≥99.2% of Enterobacterales isolates across wards and ≥99.7% isolates across infection sources globally and in all regions at ≤8 µg/mL. For resistance phenotypes, ATM-AVI demonstrated sustained activity across wards and infection sources by inhibiting ≥98.5% and ≥99.1% of multidrug-resistant (MDR) isolates, ≥98.6% and ≥99.1% of ESBL-positive isolates, ≥96.8% and ≥90.9% of carbapenem-resistant (CR) isolates, and ≥96.8% and ≥97.4% of MBL-positive isolates, respectively, at ≤8 µg/mL globally and across regions. Overall, our study demonstrated that ATM-AVI represents an important therapeutic option for infections caused by Enterobacterales, including key resistance phenotypes across different wards and infection sources.

The carbapenem inoculum effect provides insight into the molecular mechanisms underlying carbapenem resistance in Enterobacterales

Carbapenem-resistant Enterobacterales (CRE) are important pathogens that can develop resistance via multiple molecular mechanisms, including hydrolysis or reduced antibiotic influx. Identifying these mechanisms can improve pathogen surveillance, infection control, and patient care. We investigated how resistance mechanisms influence the carbapenem inoculum effect (IE), a phenomenon where inoculum size affects antimicrobial susceptibility testing (AST). We demonstrated that seven different carbapenemases impart a meropenem IE in Escherichia coli. Across 110 clinical CRE isolates, the carbapenem IE strictly depended on resistance mechanism: all carbapenemase-producing CRE (CP-CRE) exhibited a strong IE, whereas porin-deficient CRE displayed none. Concerningly, 50% and 24% of CP-CRE isolates changed susceptibility classification to meropenem and ertapenem, respectively, across the allowable inoculum range in clinical guidelines. The meropenem IE, and the ratio of ertapenem to meropenem minimal inhibitory concentration (MIC) at standard inoculum, reliably identified CP-CRE. Understanding how resistance mechanisms affect AST could improve diagnosis and guide therapies for CRE infections.

Carbapenem resistance in Enterobacterales bloodstream infections among children with cancer or post-haematopoietic stem cell transplant: a retrospective cohort study

BACKGROUND

Risk factors for carbapenem resistance in Enterobacterales bloodstream infections among children with cancer or post-HSCT have not been thoroughly explored.

METHODS

All children with cancer or post-HSCT who developed Enterobacterales bloodstream infections in two cancer referral centres in major Colombian cities between 2012 and 2021 were retrospectively examined. When the infection episode occurred, carbapenem resistance mechanisms were evaluated according to the available methods. Data were divided in a training set (80%) and a test set (20%). Three internally validated carbapenem-resistant Enterobacterales (CRE) prediction models were created: a multivariate logistic regression model, and two data mining techniques. Model performances were evaluated by calculating the average of the AUC, sensitivity, specificity and predictive values.

RESULTS

A total of 285 Enterobacterales bloodstream infection episodes (229 carbapenem susceptible and 56 carbapenem resistant) occurred [median (IQR) age, 9 (3.5-14) years; 57% male]. The risk of CRE was 2.1 times higher when the infection was caused by Klebsiella spp. and 5.8 times higher when a carbapenem had been used for ≥3 days in the previous month. A model including these two predictive variables had a discriminatory performance of 77% in predicting carbapenem resistance. The model had a specificity of 97% and a negative predictive value of 81%, with low sensitivity and positive predictive value.

CONCLUSIONS

Even in settings with high CRE prevalence, these two variables can help early identification of patients in whom CRE-active agents are unnecessary and highlight the importance of strengthening antibiotic stewardship strategies directed at preventing carbapenem overuse.

Ertapenem Supplemented Selective Media as a New Strategy to Distinguish β-Lactam-Resistant Enterobacterales: Application to Clinical and Wastewater Samples

The increase in carbapenem-resistant Enterobacterales (CRE) is mostly driven by the spread of carbapenemase-producing (CP) strains. In New Caledonia, the majority of carbapenemases found are IMP-type carbapenemases that are difficult to detect on routine selective media. In this study, a culture-based method with ertapenem selection is proposed to distinguish non-CRE, non-CP-CRE, and CP-CRE from samples with very high bacterial loads. Firstly, assays were carried out with phenotypically well-characterized β-lactam-resistant Enterobacterales isolates. Then, this approach was applied to clinical and environmental samples. Presumptive CP-CRE isolates were finally identified, and the presence of a carbapenemase was assessed. In a collection of 27 phenotypically well-characterized β-lactam-resistant Enterobacterales, an ertapenem concentration of 0.5 µg·mL^-1 allowed distinguishing CRE from non-CRE. A concentration of 4 µg·mL^-1 allowed distinguishing CP-CRE from non-CP-CRE after nine hours of incubation. These methods allowed isolating 18 CP-CRE from hospital effluents, including the first detection of a KPC in New Caledonia. All these elements show that this cost-effective strategy to distinguish β-lactam-resistant Enterobacterales provides fast and reliable results. This could be applied in the Pacific islands or other resource-limited settings, where limited data are available.

Risk factors for acquisition of carbapenemase-producing versus non-carbapenemase-producing enterobacterales: a case-control study

OBJECTIVES

We aimed to assess the association between carbapenem-resistant Enterobacterales (CRE) colonization pressure and carbapenem exposure and acquisition of carbapenemase-producing Enterobacterales (CPE) and non-carbapenemase-producing carbapenem-resistant Enterobacterales (non-CP-CRE).

METHODS

We conducted a parallel 1:2 matched case-control study at Rambam Health Care Campus, Israel, from January 2014 to June 2017. The cases included all adults who acquired CPE or non-CP-CRE in hospital. The controls were hospitalized patients who were negative for CRE on screening and matched by age, hospitalization division and the number of hospitalization days 90 days prior to CRE screening. The exposures of interest were high CRE colonization pressure, defined as a higher-than-median proportion of CRE carriers in the concurrent patient's department before acquisition, and carbapenem exposure, assessed as days of treatment. Conditional logistic regression was used for analyses of CPE and non-CP-CRE.

RESULTS

In total, 1058 patients were included: 278 CPE and 75 non-CP-CRE cases, matched to 556 and 149 controls, respectively. High CRE colonization pressure was associated with CPE acquisition (adjusted odds ratio [aOR], 2.6; 95% CI, 1.69-4.02); however, the duration of carbapenem treatment was not (aOR, 1.004; 95% CI, 0.98-1.03; 1-day increment). The duration of carbapenem treatment was significantly associated with non-CP-CRE acquisition (aOR per day, 1.07; 95% CI, 1.03-1.11). A source patient was identified significantly more frequently in epidemiological acquisition investigations of CPE than in those of non-CP-CRE (107/240, 44.6% vs. 18/64, 28.1%, respectively; p 0.017).

CONCLUSIONS

CPE acquisition was associated with horizontal transmission, whereas non-CP-CRE was associated with carbapenem exposure. Differences in the drivers of acquisition mandate tailored infection prevention efforts.

Epidemiology and Mortality Analysis Related to Carbapenem-Resistant Enterobacterales in Patients After Admission to Intensive Care Units: An Observational Study

Purpose

The prevalence of carbapenem-resistant Enterobacterales (CRE) is rapidly increasing worldwide. Patients in the intensive care unit (ICU) are susceptible to CRE infections, and the related mortality rate is increased. It is necessary to understand CRE strains and risk factors for CRE infection in the ICU, to facilitate development of effective prophylactic strategies and treatments for ICU patients.

Patients and Methods

This observational study was conducted in a tertiary hospital between 2016 and 2021. The subjects were patients with CRE cultured from specimens obtained after ICU admission. Genotypes of strains of CRE and carbapenemase-producing Enterobacterales (CPE) were identified, CRE infection was distinguished from mere colonization, and the clinical course of these patients was investigated.

Results

Among 327 CRE cases, 84 (25.7%) showed infection and 243 (74.3%) showed colonization. Of these patients, 138 (42.2%) died. The CRE strains were Klebsiella pneumoniae (253 cases, 77.4%), Enterobacter cloacae (44 cases, 13.5%), and Escherichia coli (15 cases, 4.6%). Among CRE cases, CPE was found in 249 (76.1%), including Klebsiella pneumoniae carbapenemase (KPC) in 164 (65.9%), and Guiana extended-spectrum (GES) in 64 (25.7%). A bedridden state, longer ICU stay, chronic kidney disease, malignancy, connective tissue disease, ICU admission for cardiac arrest, and CRE infection were associated with higher mortality, but cerebrovascular disease and ICU admission for trauma were associated with lower mortality. GES outbreak was caused by person-to-person transmission and was controlled through active surveillance.

Conclusion

The frequency of K. pneumoniae and KPC was the highest, but E. cloacae and GES was characteristically high in this study. Active CRE surveillance can be helpful for controlling outbreak.

Characteristics of Carbapenem-resistant Klebsiella pneumoniae in sewage from a tertiary hospital in Jilin Province, China

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection is a serious problem in hospitals worldwide. We monitored a tertiary hospital in Changchun, Jilin Province, China, and found that CRKP was the major species among the carbapenem-resistant isolates in sewage. Subsequently, we evaluated the drug susceptibility, resistance genes, virulence genes, outer pore membrane protein-related genes (OmpK35 & OmpK 36), multi-locus sequence typing and replicons, biofilm formation capabilities, and resistance to chlorine-containing disinfectants among KP isolates. Identification of drug sensitivity, multiple resistance profiles were observed including 77 (82.80%) multidrug resistant (MDR), 16 (17.20%) extensive drug resistant (XDR). Some antibiotic resistance genes were detected, the most prevalent carbapenemase gene was blaKPC, and 16 resistance genes were associated with other antibiotics. In addition, 3 (3.23%) CRKP isolates demonstrated loss of OmpK-35 and 2 (2.15%) demonstrated loss of OmpK-36. In the detection of multi-locus sequence typing (MLST), 11 ST11 isolates carried virulence genes. The most common replicon type was IncFII. Biofilm-forming capabilities were demonstrated by 68.8% of the isolates, all of which were resistant to chlorine-containing disinfectants. The results of the study showed that antibiotic-resistant isolates, especially CRKP, could resist disinfectants in hospital wastewater, and improper treatment of hospital wastewater may lead to the spread of drug-resistant bacteria and their genes. Thus, these bacteria must be eliminated before being discharged into the municipal sewage system.

Risk Factors and Prognosis of Carbapenem-Resistant Organism Colonization and Infection in Acute Cholangitis

Background

To identify the risk factors and prognosis of carbapenem-resistant organisms (CRO) in patients with acute cholangitis.

Methods

This retrospective observational study was conducted to explore the risk factors and prognosis of CRO infection in 503 acute cholangitis patients diagnosed between July 2013 and January 2022 at the First Affiliated Hospital of Chongqing Medical University, who were divided into a CRO group and non-CRO group based on the presence or absence of CRO. Univariate, multivariate analyses, and the proportional hazards model were used to compare the risk factors and prognosis of CRO suffering in patients with acute cholangitis.

Results

We identified 35 patients colonized with CRO from 503 acute cholangitis patients. In the multivariate analysis, tumor (OR=7.09, 95% CI=1.11-45.30, P=0.038) and chronic kidney disease (OR=8.70, 95% CI=2.11-35.88, P=0.003) were ascertained as the risk factors of the occurrence on CRO infection under the background of acute cholangitis. CRO infection was identified as an independent risk factor for acute cholangitis patient death (HR=5.147, 95% CI=1.475-17.595, P=0.01) by Cox proportional-hazards regression.

Conclusion

Tumor and chronic kidney disease may be risk factors for CRO infection. Patients diagnosed with acute cholangitis further infected with CRO had a poor prognosis and a more severe mortality. Active screening for CRO is expected to facilitate early prevention, diagnosis, and treatment of high-risk patients.

Molecular Epidemiology, Clinical Characteristics and Risk Factors for Bloodstream Infection of Multidrug-Resistant Klebsiella pneumoniae Infections in Pediatric Patients from Tianjin, China

PURPOSE

The data on pediatrics with Multidrug-Resistant (MDR) Klebsiella pneumoniae infections are scarce. This study aims to investigate the molecular epidemiology of MDR Klebsiella pneumoniae, detect the mechanism of drug resistance, and determine the clinical risk factors for carbapenem-resistant Klebsiella pneumonia (CRKP) bloodstream infections (BSIs) in a children's hospital.

METHODS

A total of 62 strains were collected from Tianjin Children's Hospital. Carba NP and polymerase chain reactions (PCR) were performed to detect MDR mechanisms. Multilocus sequence typing (MLST) was used for analyzing strain homology. Clinical data were collected and logistic regression was used for BSI risk factors.

RESULTS

ST11 was the principal ST among the CRKP isolates clinically, accounting for 56.45% (35/62); there were also 57.14% (20/35) ST11 CRKP strains co-carrying bla NDM-5 and bla KPC-2, which were resistant to most of the tested antibiotics, being susceptible only to cotrimoxazole and tigecycline. The clinical data showed that 72.73% (40/55) of children with CRKP infection had serious underlying diseases; 20.00% (11/55) patients developed BSIs with the potential to cause multiple organ failure, shock and death. The logistic regression showed that the risk of BSIs caused by CRKP strain infections in children with hematological malignancies after chemotherapy was 7 times that of other children (95%Cl: 1.298-45.415, P=0.025).

CONCLUSION

ST11 was the prevalent clone in our hospital. The emergence of ST11 CRKP co-carrying bla NDM-5 and bla KPC-2 should be a cause for alarm as they were resistant to most of the tested antibiotics. CRKP strain infections are mainly occurring in young immunocompromised patients and the chemotherapy for hematological malignancies is an independent risk factor for BSIs.

Characterisation of Non-Carbapenemase-Producing Carbapenem-Resistant Klebsiella pneumoniae Based on Their Clinical and Molecular Profile in Malaysia

Non-carbapenemase-producing carbapenem-resistant Klebsiella pneumoniae (NC-CRKP) confers carbapenem resistance through a combination of chromosomal mutations and acquired non-carbapenemase resistance mechanisms. In this study, we aimed to evaluate the clinical and molecular profiles of NC-CRKP isolated from patients in a tertiary teaching hospital in Malaysia from January 2013 to October 2019. During the study period, 54 NC-CRKP-infected/colonised patients’ isolates were obtained. Clinical parameters were assessed in 52 patients. The all-cause in-hospital mortality rate among NC-CRKP patients was 46.2% (24/52). Twenty-three (44.2%) patients were infected, while others were colonised. Based on the Charlson Comorbidity Index (CCI) score, 92.3% (48/52) of the infected/colonised patients had a score of ≥ 1. Resistance genes found among the 54 NC-CRKP isolates were bla_TEM, bla_SHV, bla_CTX-M, bla_OXA, and bla_DHA. Porin loss was detected in 25/54 (46.3%) strains. None of the isolated strains conferred carbapenem resistance through the efflux pumps system. In conclusion, only 25/54 (46.3%) NC-CRKP conferred carbapenem resistance through a combination of porin loss and the acquisition of non-carbapenemase resistance mechanisms. The carbapenem resistance mechanisms for the remaining strains (53.7%) should be further investigated as rapid identification and distinction of the NC-CRKP mechanisms enable optimal treatment and infection control efforts.

A matrix management of prevention and control for carbapenem-resistant Enterobacteriaceae in an urban compact medical union

PURPOSE

To understand the epidemiological characteristics of nosocomial infection of carbapenem-resistant Enterobacteriaceae (CRE) in an urban medical union includes 10 medical hospitals with different number of beds in China.

METHODS

Epidemiological data on age, department, and infection of CRE cases detected from January 2014 to December 2021 were collected via a real-time hospital-infection monitoring system or manually for subsequent characterization. A multi-departmental and multi-disciplinary matrix (MMM) management of CRE was established and implemented within a medical union.

RESULTS

A total of 1327 cases of CRE infection were detected during the 8 years, of which 352 were due to nosocomial infection, with an infection morbidity of 0.046% and a resistance rate of 10.79%. The morbidity of CRE infection showed a trend of year-to-year fluctuation. The morbidity of CRE infection was significantly higher in winter and spring than that in summer and autumn, significantly higher in men than in women (χ² ​= ​55.891, p ​< ​0.001), and 3 times higher in elderly patients ≥65 years old than in patients <65 years old (χ² ​= ​117.517, p ​< ​0.001). The morbidity of CRE infection after intervention with MMM management decreased significantly from 0.071% to 0.042% (χ² ​= ​15.628, p ​< ​0.001).

CONCLUSIONS

CRE prevention and control practice should be adapted to seasonal variations, gender and age differences. The effective prevention and control of CRE nosocomial infections can be achieved by implementing MMM management within a medical association.

Systematic Analysis of Mobile Genetic Elements Mediating β-Lactamase Gene Amplification in Noncarbapenemase-Producing Carbapenem-Resistant Enterobacterales Bloodstream Infections

Noncarbapenemase-producing carbapenem-resistant Enterobacterales (non-CP-CRE) are increasingly recognized as important contributors to prevalent carbapenem-resistant Enterobacterales (CRE) infections. However, there is limited understanding of mechanisms underlying non-CP-CRE causing invasive disease. Long- and short-read whole-genome sequencing was used to elucidate carbapenem nonsusceptibility determinants in Enterobacterales bloodstream isolates at MD Anderson Cancer Center in Houston, Texas. We investigated carbapenem nonsusceptible Enterobacterales (CNSE) mechanisms (i.e., isolates with carbapenem intermediate resistance phenotypes or greater) through a combination of phylogenetic analysis, antimicrobial resistance gene detection/copy number quantification, porin assessment, and mobile genetic element (MGE) characterization. Most CNSE isolates sequenced were non-CP-CRE (41/79; 51.9%), whereas 25.3% (20/79) were Enterobacterales with intermediate susceptibility to carbapenems (CIE), and 22.8% (18/79) were carbapenemase-producing Enterobacterales (CPE). Statistically significant copy number variants (CNVs) of extended-spectrum β-lactamase (ESBL) genes (Wilcoxon Test; P-value < 0.001) were present in both non-CP-CR E. coli (median CNV = 2.6×; n = 17) and K. pneumoniae (median CNV = 3.2×, n = 17). All non-CP-CR E. coli and K. pneumoniae had predicted reduced expression of at least one outer membrane porin gene (i.e., ompC/ompF or ompK36/ompK35). Completely resolved CNSE genomes revealed that IS26 and ISEcp1 structures harboring blaCTX-M variants along with other antimicrobial resistance elements were associated with gene amplification, occurring in mostly IncFIB/IncFII plasmid contexts. MGE-mediated β-lactamase gene amplifications resulted in either tandem arrays, primarily mediated by IS26 translocatable units, or segmental duplication, typically due to ISEcp1 transposition units. Non-CP-CRE strains were the most common cause of CRE bacteremia with carbapenem nonsusceptibility driven by concurrent porin loss and MGE-mediated amplification of blaCTX-M genes. IMPORTANCE Carbapenem-resistant Enterobacterales (CRE) are considered urgent antimicrobial resistance (AMR) threats. The vast majority of CRE research has focused on carbapenemase-producing Enterobacterales (CPE) even though noncarbapenemase-producing CRE (non-CP-CRE) comprise 50% or more of isolates in some surveillance studies. Thus, carbapenem resistance mechanisms in non-CP-CRE remain poorly characterized. To address this problem, we applied a combination of short- and long-read sequencing technologies to a cohort of CRE bacteremia isolates and used these data to unravel complex mobile genetic element structures mediating β-lactamase gene amplification. By generating complete genomes of 65 carbapenem nonsusceptible Enterobacterales (CNSE) covering a genetically diverse array of isolates, our findings both generate novel insights into how non-CP-CRE overcome carbapenem treatments and provide researchers scaffolds for characterization of their own non-CP-CRE isolates. Improved recognition of mechanisms driving development of non-CP-CRE could assist with design and implementation of future strategies to mitigate the impact of these increasingly recognized AMR pathogens.

Clinical Outcomes Associated with Co-infection of Carbapenem-Resistant Enterobacterales and other Multidrug-Resistant Organisms

Background

Infections with carbapenem-resistant Enterobacterales (CRE) are associated with increased risk of death. Polymicrobial infections with antimicrobial-resistance may add to the burden of clinical care and patients' clinical prognosis.

Aim

To examine the impact of CRE co-infection with other multi-drug resistant organisms (MDRO) on patient clinical outcomes.

Study Design

A retrospective observational study was conducted to compare the clinical outcomes of CRE patients who were co-infected with carbapenem-resistant Pseudomonas aeruginosa (CRPA), multidrug-resistant Acinetobacter baumannii (MDRA) and Methicillin-resistant Staphylococcus aureus (MRSA).

Results

A total of 224 CRPA and 209 MDRA co-infections with CRE were identified from 4,236 cases from 2015-2020. The overall 90-day all-cause mortality was 21.6% but increased to 35.0% and 33.5% among patients who were co-infected with CRPA and MDRA, respectively. The odds of all-cause mortality among CRE patients who were co-infected with CRPA was twice that of patients identified with CRE alone [adjusted odds ratio (AOR) = 2.02, 95% confidence interval (CI): 1.18-3.46]. Further, the odds of all-cause mortality among CRE patients who were concomitantly identified with MRSA was more than twice that of patients who were not identified with MRSA [AOR = 2.16, 95%CI:1.31-3.56]. The clinical outcome of patients with CRE did not differ significantly depending on the presence of carbapenemase genes.

Conclusion

The results show that CRPA and CRE co-infections have synergistic effects on clinical outcomes. Further investigation is necessary to understand the mechanism. Screening high risk patients for concomitant antimicrobial-resistant infections may have a significant clinical impact, including effective therapies, antibiotic stewardship, and infection control policies.

Drug Resistance Mechanism of Enterobacteriaceae with Decreased Antibiotic Sensitivity

To investigate the mechanism of antibiotic resistance in Enterobacteriaceae. Carbapenem Enterobacteriaceae bacteria isolated from a hospital from January 2015 to June 2020 were selected. Drug resistance phenotype test, drug sensitivity test, and conjugation test were used to observe the drug sensitivity results and the titer of acrB antibody. Finally, the data were statistically analyzed. All strains were resistant to ceftazidime, ceftriaxone, ertapenem, and aztreonam. 87.5% of the samples were resistant to piperacillin. Multisite sequence typing showed that 5 carbapenem-resistant Klebsiella pneumoniae belonged to 4 different types. The sequence types of kpn6099 and kpn6617 were the same. In the sensitivity comparison, Escherichia coli J53 was more sensitive to these two antibiotics, minimum inhibitory concentration values were 0.5 and 0.25 μg/ml, respectively. In addition, the sensitivity of E. coli J53 to carbapenems was slightly higher than that of kpn6617. The results showed that the enzyme-linked immunosorbent assay titer of acrB antibody was 1:40,000, and the preparation of acrB antibody was successful. Plasmid-mediated deletion of IMP-1 metallo-β-lactamase binding outer membrane protein is one of the main reasons for the decrease of antibiotic sensitivity.

Molecular epidemiology characteristics and detecting transmission of carbapenemase-producing enterobacterales in southwestern China

BACKGROUND

To investigate the genotype and clinical characteristics of carbapenem-resistant Enterobacteriaceae (CRE) strains in southwest China and provide information on the treatment stopping the spread of the infection.

METHODS

The clinical information of CRE isolates was collected from 19 hospitals in 12 cities across Sichuan Province, China, between June 2018 and April 2019. The isolates were detected by DNA sequencing of genes encoding carbapenem enzymes and multilocus sequence types (MLSTs).

RESULTS

A total of 166 nonrepetitive CRE isolates were isolated during the study period from sputum, blood, urine, and other samples. Klebsiella pneumoniae carbapenemase (KPC) was dominant in Klebsiella pneumoniae (53.9%), followed by New Delhi metallo-β-lactamase (NDM) (42.1%). A total of 43 STs were detected. The most common ST of K. pneumoniae was ST11, and that of Escherichia coli was ST410. Pairwise single nucleotide polymorphism (SNP) distances and the likelihood of local transmission by epidemiology were plotted for each species. About 65% of these pairs had ≤ 20 pairwise SNPs.

CONCLUSION

A large number of CRE strains carried carbapenemase. Although NDM-ST12 K. pneumoniae should not be disregarded, KPC-ST11is the predominant strain. Thus, the possibility of transmission between E. coli and K. pneumoniae could not be ignored.

Trends of Bloodstream Infections in a University Hospital During 12 Years

This study aims to investigate trends in bloodstream infections and their antimicrobial susceptibility profiles over 12 years in our hospital. This retrospective study was carried out in the Bursa Uludag University Hospital, Turkey, during 2008–2019. Blood cultures from patients were performed using BACTEC System. Isolates were identified with Phoenix System until 2018 and “matrix-assisted laser desorption ionization time-of-flight mass spectrometry” (MALDI-TOF MS) in 2019. Antibiotic susceptibility testing was performed with Phoenix System. Patient data came from the BD EpiCenter™ data management system. Escherichia coli was found to be the most common Gram-negative (11.6%), and coagulase-negative staphylococci were the most common Gram-positive (10.1%) monomicrobial growth. Overall, there was a significant increase in rates of extended-spectrum β-lactamase positive E. coli (p = 0.014) and Klebsiella pneumonia (p < 0.001), carbapenem-resistant E. coli (p < 0.001), and K. pneumoniae (p < 0.001) and colistin-resistant K. pneumoniae (p < 0.001) and Acinetobacter baumannii (p < 0.001) over 12 years. Carbapenem and colistin resistance has increased dramatically in recent years. We believe that regular monitoring of the distribution of pathogens and antibiotic susceptibility profiles, especially in intensive care units, can contribute to evidence for the increase in resistant microorganisms and help prevent their spread with antimicrobial stewardship and infection control policies.

Investigating forthcoming strategies to tackle deadly superbugs: current status and future vision

INTRODUCTION

Superbugs are microorganisms that cause disease and have increased resistance to the treatments typically used against infections. Recently, antibiotic resistance development has been more rapid than the pace at which antibiotics are manufactured, leading to refractory infections of pathogenic bacteria. Scientists are concerned that a particularly virulent and lethal "superbug" will one day join the ranks of existing bacteria that cause incurable diseases, resulting in a global health disaster on the scale of the Black Death.

AREAS COVERED

Therefore, this study highlights the current developments in the management of antibiotic-resistant bacteria and recommends strategies for further regulating antibiotic-resistant microorganisms associated with the healthcare system. This review also addresses the origins, prevalence, and pathogenicity of superbugs, and the design of antibacterial against these growing multidrug-resistant organisms from a medical perspective.

EXPERT OPINION

It is recommended that antimicrobial resistance (AMR) should be addressed by limiting human-to-human transmission of resistant strains, lowering the use of broad-spectrum antibiotics, and developing novel antimicrobials. Using the risk-factor domains framework from this study would assure that not only clinical but also community and hospital-specific factors are covered, lowering the chance of confounders. Extensive subjective research is necessary to fully understand the underlying factors and uncover previously unexplored areas.

Exposure to World Health Organization's AWaRe antibiotics and isolation of multidrug resistant bacteria: a systematic review and meta-analysis

BACKGROUND

Antibiotic use drives antibiotic resistance.

OBJECTIVES

To systematically review the literature and estimate associations between prior exposure to antibiotics across World Health Organization's (WHO) AWaRe categories (Access, Watch, Reserve) and isolation of critical and high-priority multidrug resistant organisms (MDROs) on the WHO priority pathogen list.

DATA SOURCES

Embase, Ovid Medline, Scopus, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov (from inception to 20/08/2020).

STUDY ELIGIBILITY CRITERIA

Case-control, cohort, or experimental studies that assessed the risk of infection/colonization with MDROs.

PARTICIPANTS

Inpatients or outpatients of any age and sex.

INTERVENTIONS

Prior exposure to antibiotics that could be categorized into the AWaRe framework.

DATA ANALYSIS

Tailored design-specific checklists applied to each included study. For each antibiotic/class, crude odds ratios (ORs) were pooled through random-effects meta-analyses, both overall and by MDRO. Heterogeneity was examined.

RESULTS

We identified 349 eligible studies. All were observational, prone to bias due to design and lack of adjustment for confounding, and not primarily designed to compare associations across AWaRe categories. We found statistically significant associations between prior exposure to almost all antibiotics/classes across AWaRe categories and colonization/infection with any MDRO. We observed higher ORs for Watch and Reserve antibiotics than with Access antibiotics. First generation cephalosporins (Access) had the least association with any MDRO colonization/infection (58 studies; OR = 1.2 [95% CI: 1.0-1.4]), whereas strongest associations were estimated for linezolid (Reserve) (22 studies; OR = 2.6 [95% CI: 2.1-3.1]), followed by carbapenems (Watch) (237 studies; OR = 2.3 [95% CI: 2.1-2.5]). There was high heterogeneity for all antibiotic/MDRO associations.

CONCLUSIONS

Optimising use of Access antibiotics is likely to reduce the selection of MDROs and global antibiotic resistance. Despite data limitations, our study offers a strong rationale for further adoption of AWaRe as an important tool to improve antibiotic use globally.

Development of Microfluidic Chip-Based Loop-Mediated Isothermal Amplification (LAMP) Method for Detection of Carbapenemase Producing Bacteria

The rapid and accurate diagnostic methods to identify carbapenemase-producing organisms (CPO) is of great importance for controlling the CPO infection. Herein, we have developed a microfluidic chip-based technique to detect CPO and assessed its clinical value in detecting CPO directly from blood cultures (BCs). The detection performance of the microfluidic chip-based LAMP amplification method was analyzed retrospectively on a collection of 192 isolates including molecularly characterized 108 CPO and 84 non-CPO and prospectively on a collection of 133 positive BCs with or without CPO suspicion, respectively. In the retrospective study, the microfluidic chip-based LAMP amplification method exhibited 87.5% accuracy (95% CI [82.0–91.5]), 97.7% sensitivity (95% CI [91.2–99.6]), 78.8% specificity (95% CI [69.5–86.0]), 79.6% positive predictive value (PPV) (95% CI [70.6–86.5]) and 97.6% negative predictive value (NPV) (95% CI [90.9–99.6]). Among the 192 isolates, 22 (11.5%) false-positives (FP) and 2 (1.0%) false negatives (FN) were observed. In the prospective study, the 133 routine isolates of positive BCs including 18 meropenem-resistant CPO and 115 non-CPO were assessed, and 4 FP were observed in non-CPO and CPO, respectively. The current method showed a total detection performance of 94.0% accuracy (95% CI [88.4–97.1]), 100.0% sensitivity (95% CI [73.2–100.0]), 93.2% specificity (95% CI [86.7–96.8]), 63.6% PPV (95% CI [40.8–82.0]) and 100.0% NPV (95% CI [95.8–100.0]). In summary, the microfluidic chip-based LAMP amplification method is reliable for the rapid screening and detection of CPO with high accuracy, sensitivity, and specificity, and could easily be implemented in clinical microbiology laboratories.

IMPORTANCE Rapid and accurate identification of CPO may reduce the genetic exchanges among bacteria and prevent further dissemination of carbapenemases to non-CPO. The current method had designed microfluidic chip-based LAMP amplification method for multiplex detection of carbapenemase genes and evaluated the detection performance of the newly method. The current method can rapidly screen and detect CPO with high accuracy, sensitivity, and specificity, and could easily be implemented in clinical microbiology laboratories, as this will reduce the carbapenem resistance issues worldwide.

Prevalence of Multidrug-Resistant CTX-M Extended Spectrum Beta-Lactamase-Producing Escherichia coli From Different Bovine Faeces in China

CTX-M extended spectrum beta-lactamase-producing Escherichia coli cause severe health hazards in livestock breeding. To date, little is known about antibiotic resistance differences among bacterial isolates from yaks, cows, and beef cattle; therefore, the aims of this study were to analyse the prevalence of CTX-M-producing E. coli in yak, beef cattle, and dairy cattle feces from different provinces in China. A total of 790 fecal samples from yaks, beef cattle, and dairy cows were used. Among all the samples, 523 non duplicate E. coli isolates were identified, and 29.6% of samples harbored CTX-M producers. The results showed that these E. coli strains harbored 15 clusters of CTX-M genes: CTX-M-79, CTX-M-55, CTX-M-15, CTX-M-14, CTX-M-28, CTX-M-179, CTX-M-65, CTX-M-24, CTX-M-27, CTX-M-102, CTX-M-105, CTX-M-173, CTX-M-238, CTX-M-196, and CTX-M-10. The dominant resistance genes were CTX-M-15, CTX-M-14, and CTX-M-55. Moreover, the distribution of CTX-M genes was related to geographical region. Based on the above findings, we reasoned that bovines are potential reservoirs of antibiotic resistance, and this problem should be given adequate attention.

Unraveling the Diversity of Co-Colonization by CPE

Antibiotic-resistant bacteria, and more specifically, carbapenem-producing Enterobacterales (CPE) strains, are increasing worldwide. Despite their growing prevalence, in most high-income countries, the detection of CPE is still considered a low-frequency event. Sporadically, patients co-colonized with distinct CPE strains and/or different carbapenemase enzymes are detected. In this paper, we present three cases that illustrate the underlying mechanisms of co-colonization, focusing on horizontal gene transfer (HGT) and patient-to-patient transmission. We also demonstrate the diversity of CPE species and discuss the potential consequences of co-colonization.

Association Between Types of Carbapenemase and Clinical Outcomes of Infection Due to Carbapenem Resistance Enterobacterales

Purpose

Compared with non-carbapenemase producing carbapenem-resistant Enterobacterales (non-CP-CRE), carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) are associated with considerable mortality. However, given that the patients are treated with various therapeutic options, it remains unclear whether differences in types of carbapenemase genes yield different mortality rates. Therefore, this study aims to identify carbapenemase genes and identify whether clinical outcomes differ according to the prevalence of genotype and phenotype of carbapenemase among Enterobacterales clinical isolated.

Patients and Methods

A retrospective cohort study was performed to determine whether types of carbapenemase genes have an impact on clinical outcomes. Carbapenem-resistant clinical isolates were collected at a tertiary care university hospital in Songkhla, Thailand, between June 2018 and February 2020. Demographic and microbiological data such as antimicrobial susceptibility, carbapenemase genes, and overall mortality were evaluated.

Results

A total of 121 Enterobacterales clinical isolated were evaluated. The bla_NDM-1 gene was detected in 44% of the isolates, followed by bla_OXA-48 (28%) and bla_NDM-1/OXA-48 (28%). NDM-1- or NDM-1/OXA-48- producing isolates were more likely to require meropenem MICs of ≥16 mg/L, while OXA-48-producing isolates were more likely to require meropenem MICs of <16 mg/L. The patients with NDM-1 or NDM-1/OXA-48 had a higher 14 days mortality rate than those with OXA-48 after treating with carbapenem-containing regimens (P-value 0.001) or colistin-containing regimens (P-value < 0.001).

Conclusion

Our findings suggest that the mortality for CP-CRE infection in patients with NDM-1 or NDM-1/OXA-48 was higher than the mortality in those with OXA-48, which It seems that the type of carbapenemase gene may affect meropenem MIC levels. Hence, in treatment decisions involving the use of either carbapenem-containing regiment or colistin-containing regiment in patients with CP-CRE infection, especially those in the NDM-1 and NDM-1/OXA-48 groups, the patient symptoms should be closely monitored.

Comparative Genomics Revealed Fluoroquinolone Resistance Determinants and OmpF Deletion in Carbapenem-Resistant Escherichia coli

Escherichia coli (E. coli) is a major causative organism of complicated urinary tract infections, bloodstream infections, and pneumonia. With the widespread use of antimicrobial agents, the prevalence of carbapenem resistance in E. coli has been increasing with limited therapeutic options. Fluoroquinolone remains a choice in carbapenem-resistant E. coli (CREc) that were once susceptible to the drug. Despite robust studies on the fluoroquinolone-resistant mechanisms of E. coli, few studies focused specifically on the group of CREc. In this study, we used comparative genomics to identify the fluoroquinolone-resistant mechanisms of CREc and detected gyrA D87N mutation in all the fluoroquinolone-resistant and CREc. Moreover, to investigate the mechanism underlying non-carbapenemase-producing carbapenem-resistant E. coli, we targeted the complete genome sequences for in-depth analysis and found a deletion in OmpF (DEL264-269) that might contribute to carbapenem resistance, which has not been reported before. Further studies focusing on the impact of these mutations on the expression levels are warranted. We further investigate the MLST, serotype, fimH type, phylogroup, and clinical characteristics of the CREc. Combination analysis of clinical and genomic characteristics suggests the polyclonal and highly diverse nature of the CREc in Taiwan. This study provides an insight into the molecular epidemiology of CREc in Taiwan.

Global Threat of Carbapenem-Resistant Gram-Negative Bacteria

Infections caused by multidrug-resistant (MDR) and extensively drug-resistant (XDR) Gram-negative bacteria (GNB), including carbapenem-resistant (CR) Enterobacterales (CRE; harboring mainly bla_KPC, bla_NDM, and bla_OXA-48-like genes), CR- or MDR/XDR-Pseudomonas aeruginosa (production of VIM, IMP, or NDM carbapenemases combined with porin alteration), and Acinetobacter baumannii complex (producing mainly OXA-23, OXA-58-like carbapenemases), have gradually worsened and become a major challenge to public health because of limited antibiotic choice and high case-fatality rates. Diverse MDR/XDR-GNB isolates have been predominantly cultured from inpatients and hospital equipment/settings, but CRE has also been identified in community settings and long-term care facilities. Several CRE outbreaks cost hospitals and healthcare institutions huge economic burdens for disinfection and containment of their disseminations. Parenteral polymyxin B/E has been observed to have a poor pharmacokinetic profile for the treatment of CR- and XDR-GNB. It has been determined that tigecycline is suitable for the treatment of bloodstream infections owing to GNB, with a minimum inhibitory concentration of ≤ 0.5 mg/L. Ceftazidime-avibactam is a last-resort antibiotic against GNB of Ambler class A/C/D enzyme-producers and a majority of CR-P. aeruginosa isolates. Furthermore, ceftolozane-tazobactam is shown to exhibit excellent in vitro activity against CR- and XDR-P. aeruginosa isolates. Several pharmaceuticals have devoted to exploring novel antibiotics to combat these troublesome XDR-GNBs. Nevertheless, only few antibiotics are shown to be effective in vitro against CR/XDR-A. baumannii complex isolates. In this era of antibiotic pipelines, strict implementation of antibiotic stewardship is as important as in-time isolation cohorts in limiting the spread of CR/XDR-GNB and alleviating the worsening trends of resistance.

Discovery of a Tricyclic β-Lactam as a Potent Antimicrobial Agent against Carbapenem-Resistant Enterobacterales, Including Strains with Reduced Membrane Permeability and Four-Amino Acid Insertion into Penicillin-Binding Protein 3: Structure-Activity-Relationships and In Vitro and In Vivo Activities

The current worldwide emergence of carbapenem-resistant enterobacterales (CREs) constitutes an important growing clinical and public health threat. Acquired carbapenemases are the most important determinants of resistance to carbapenems. In the development of the previously reported tricyclic β-lactam skeleton which exhibits potent antibacterial activities against several problematic β-lactamase-producing CREs without a β-lactamase inhibitor, we found that these activities were reduced against clinical isolates with resistance mechanisms other than β-lactamase production. These mechanisms were the reduction of outer membrane permeability with the production of β-lactamases and the insertion of four amino acids into penicillin-binding protein 3. Here, we report the discovery of a potent compound that overcomes these resistance mechanisms by the conversion of the alkoxyimino moiety of the aminothiazole side chain in which a hydrophilic functional group is introduced and the carboxylic acid of the alkoxyimino moiety is converted to reduce the negative charge of the whole molecule from 2 to 1. This potent tricyclic β-lactam is a promising drug candidate for infectious diseases caused by CREs due to its potent therapeutic efficacy in the neutropenic mouse lung infection model and low frequency of producing spontaneously resistant mutants.

Outbreak of NDM-1-Producing Escherichia coli in a Coronavirus Disease 2019 Intensive Care Unit in a Mexican Tertiary Care Center

Emergency department areas were repurposed as intensive care units (ICUs) for patients with acute respiratory distress syndrome during the initial months of the coronavirus disease 2019 (COVID-19) pandemic. We describe an outbreak of New Delhi metallo-β-lactamase 1 (NDM-1)-producing Escherichia coli infections in critically ill COVID-19 patients admitted to one of the repurposed units. Seven patients developed infections (6 ventilator-associated pneumonia [VAP] and 1 urinary tract infection [UTI]) due to carbapenem-resistant E. coli, and only two survived. Five of the affected patients and four additional patients had rectal carriage of carbapenem-resistant E. coli. The E. coli strain from the affected patients corresponded to a single sequence type. Rectal screening identified isolates of two other sequence types bearing bla_NDM-1. Isolates of all three sequence types harbored an IncFII plasmid. The plasmid was confirmed to carry bla_NDM-1 through conjugation. An outbreak of clonal NDM-1-producing E. coli isolates and subsequent dissemination of NDM-1 through mobile elements to other E. coli strains occurred after hospital conversion during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. This emphasizes the need for infection control practices in surge scenarios.

IMPORTANCE The SARS-CoV-2 pandemic has resulted in a surge of critically ill patients. Hospitals have had to adapt to the demand by repurposing areas as intensive care units. This has resulted in high workload and disruption of usual hospital workflows. Surge capacity guidelines and pandemic response plans do not contemplate how to limit collateral damage from issues like hospital-acquired infections. It is vital to ensure quality of care in surge scenarios.

Distinctive Features of Ertapenem-Mono-Resistant Carbapenem-Resistant Enterobacterales in the United States: A Cohort Study

Background

Carbapenem-resistant Enterobacterales (CRE) are highly antibiotic-resistant bacteria. Whether CRE resistant only to ertapenem among carbapenems (ertapenem “mono-resistant”) represent a unique CRE subset with regards to risk factors, carbapenemase genes, and outcomes is unknown.

Methods

We analyzed surveillance data from 9 CDC Emerging Infections Program (EIP) sites. A case was the first isolation of a carbapenem-resistant Enterobacter cloacae complex, Escherichia coli, Klebsiella aerogenes, K. oxytoca, K. pneumoniae, or K. variicola from a normally sterile site or urine in an EIP catchment area resident in 2016–2017. We compared risk factors, carbapenemase genes, antibiotic susceptibility, and mortality of ertapenem “mono-resistant” cases to “other” CRE cases (resistant to ≥1 carbapenem other than ertapenem) and analyzed risk factors for mortality.

Results

Of 2009 cases, 1249 (62.2%) were ertapenem-mono-resistant and 760 (37.8%) were other CRE. Ertapenem-mono-resistant CRE cases were more frequently ≥80 years old (29.1% vs 19.5%; P < .0001) and female (67.9% vs 59.0%; P < .0001). Ertapenem-mono-resistant isolates were more likely to be Enterobacter cloacae complex (48.4% vs 15.4%; P < .0001) but less likely to be isolated from a normally sterile site (7.1% vs 11.7%; P < .01) or to have a carbapenemase gene (2.4% vs 47.4%; P < .0001). Ertapenem-mono-resistance was not associated with 90-day mortality in logistic regression models. Carbapenemase-positive isolates were associated with mortality (odds ratio, 1.93; 95% CI, 1.30–2.86).

Conclusions

Ertapenem-mono-resistant CRE rarely have carbapenemase genes and have distinct clinical and microbiologic characteristics from other CRE. These findings may inform antibiotic choice and infection prevention practices, particularly when carbapenemase testing is not available.

Molecular Surveillance of Carbapenem-Resistant Gram-Negative Bacteria in Liver Transplant Candidates

Background: Carbapenem-resistant Gram-negative bacteria (CRGN) cause life-threatening infections due to limited antimicrobial treatment options. The occurrence of CRGN is often linked to hospitalization and antimicrobial treatment but remains incompletely understood. CRGN are common in patients with severe illness (e.g., liver transplantation patients). Using whole-genome sequencing (WGS), we aimed to elucidate the evolution of CRGN in this vulnerable cohort and to reconstruct potential transmission routes.

Methods: From 351 patients evaluated for liver transplantation, 18 CRGN isolates (from 17 patients) were analyzed. Using WGS and bioinformatic analysis, genotypes and phylogenetic relationships were explored. Potential epidemiological links were assessed by analysis of patient charts.

Results: Carbapenem-resistant (CR) Klebsiella pneumoniae (n=9) and CR Pseudomonas aeruginosa (n=7) were the predominating pathogens. In silico analysis revealed that 14/18 CRGN did not harbor carbapenemase-coding genes, whereas in 4/18 CRGN, carbapenemases (VIM-1, VIM-2, OXA-232, and OXA-72) were detected. Among all isolates, there was no evidence of plasmid transfer-mediated carbapenem resistance. A close phylogenetic relatedness was found for three K. pneumoniae isolates. Although no epidemiological context was comprehensible for the CRGN isolates, evidence was found that the isolates resulted of a transmission of a carbapenem-susceptible ancestor before individual radiation into CRGN.

Conclusion: The integrative epidemiological study reveals a high diversity of CRGN in liver cirrhosis patients. Mutation of carbapenem-susceptible ancestors appears to be the dominant way of CR acquisition rather than in-hospital transmission of CRGN or carbapenemase-encoding genetic elements. This study underlines the need to avoid transmission of carbapenem-susceptible ancestors in vulnerable patient cohorts.

Clonal Dissemination of Multiple Carbapenemase Genes in Carbapenem-Resistant Enterobacterales Mediated by Multiple Plasmids in China

Background

Carbapenem-resistant Enterobacterales (CRE) are rapidly increasing worldwide in last two decades and lead few antibiotics for treatment. The molecular epidemiology of CRE in China was investigated to provide basis for clinical rational use of antibiotics and prevent its spread.

Methods

All CRE isolates in this study were collected from 11 hospitals from October 2015 to July 2018. The isolates were subjected to antimicrobial susceptibility tests, PCR molecular identification, pulsed-field gel electrophoresis, and multilocus sequence typing.

Results

Among the 399 CRE isolates, 51.6% (206/399) harbored carbapenemase genes. Three carbapenemase genes were detected, namely bla _KPC-2, bla _NDM-1, and bla _IMP at rates of 29.8% (119/399), 17.5% (70/399), and 4.0% (16/399), respectively. In Klebsiella pneumoniae (350) and Escherichia coli (26), bla _KPC-2 (33.4%, 117/350) and bla _NDM-1 (61.5%, 16/26) were the predominant genes. The most common genes in the CRE isolates were bla _KPC (85.5%) and bla _NDM-1 (76.5%) from adults and children, respectively. Particularly, ST11 K. pneumoniae with bla _KPC-2 harbored by IncFII plasmids were distributed in both general and primary hospitals, suggesting a clonal transmission pattern at these sites. In addition, the clonal distribution of ST2407 K. pneumoniae with bla _NDM-1 located on IncX3 plasmids and bla _IMP-38-positive ST307 K. pneumoniae were detected in a children's hospital.

Conclusion

The distribution of carbapenemase genes differed among strains and age groups. Multiple carbapenemase genes in the CRE strains were clonally disseminated in the tested regions mediated by multiple plasmids. Therefore, CRE monitoring should be increased and measures should be adopted to prevent its transmission.

Comparing mortality in patients with carbapenemase-producing carbapenem resistant Enterobacterales and non-carbapenemase-producing carbapenem resistant Enterobacterales bacteremia

Carbapenem-resistant Enterobacterales (CRE) are classified as either carbapenemase-producing CRE (CP-CRE) or non-carbapenemase-producing CRE (non-CP-CRE) based on their mechanism of carbapenem resistance. Few studies have compared outcomes associated with each type of infection. We attempted to determine if either CRE subset is associated with increased mortality. We performed a retrospective observational study to collect demographic, clinical and outcomes data to compare patients with CP-CRE and non-CP-CRE bacteremia. Of 146 cases analyzed, 88/146 (60%) were CP-CRE and 58/146 (40%) were non-CP-CRE. Patients with CP-CRE bacteremia were less likely to receive active empiric or targeted antibiotic therapy. Non-CP-CRE bacteremia was associated with a 2.4 times higher hazard of death at 30 days after bacteremia onset compared to CP-CRE (HR, 2.4; 95% CI, 1.2, 4.6). Patients with non-CP-CRE bacteremia had a higher hazard of death at 30 days after bacteremia onset compared to those with CP-CRE bacteremia.

Global molecular epidemiology of carbapenem-resistant Escherichia coli (2002-2017)

The emergence of carbapenem-resistant (CR) Escherichia coli obliges an assessment of such strains' molecular epidemiology. Accordingly, we characterized in detail a globally distributed collection of CR E. coli isolates, then explored for associations between geographical origin and bacterial traits, and between different bacterial traits. We used established PCR-based assays and broth microdilution MIC determinations to characterize 343 global CR (i.e., non-susceptible to ≥ 1 carbapenem) extraintestinal E. coli isolates (2002-2017) for diverse molecular traits-including phylogroups, sequence types (STs), beta-lactamase genes, and 51 virulence genes-and susceptibility to 12 relevant antimicrobial agents. The study population was tremendously diverse according to all assessed variables. Nonetheless, certain geographically aligned, unifying themes emerged. These included an association of an Asia/West Pacific origin with non-B2/D/F phylogroups and STs, lower molecularly inferred virulence, more extensive resistance, and specific resistance genes (notably, metallo-beta-lactamases). Likewise, U.S. isolates from the central region, vs. other regions, were more virulent-appearing and more often from phylogroup B2 and ST131, but less extensively resistant and more often carbapenemase-gene negative. The global CR E. coli population is highly diverse according to multiple characteristics and varies significantly by geographical region. This predictably will pose challenges for prevention and management, and obliges ongoing surveillance.

Molecular Characterization of Carbapenem Resistant Klebsiella pneumoniae in Malaysia Hospital

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) is a great concern, as carbapenems are the last-line therapy for multidrug-resistant Gram-negative bacteria infections. This study aims to report the epidemiology of CRKP in a teaching hospital in Malaysia based on the molecular genotypic and clinical characteristics of the isolates. Sixty-three CRKP strains were isolated from a tertiary teaching hospital from January 2016 until August 2017. Carbapenemase genes were detected in 55 isolates, with bla_OXA-48 (63.5%) as the predominant carbapenemase gene, followed by bla_NDM (36.5%). At least one porin loss was detected in nine isolates. Overall, 63 isolates were divided into 30 clusters at similarity of 80% with PFGE analysis. Statistical analysis showed that in-hospital mortality was significantly associated with the usage of central venous catheter, infection or colonization by CRKP, particularly NDM-producers. In comparison, survival analysis using Cox proportional hazards regression identified a higher hazard ratio for patients with a stoma and patients treated with imipenem but a lower hazard ratio for patients with NDM-producing CRKP. OXA-48 carbapenemase gene was the predominant carbapenemase gene in this study. As CRKP infection could lead to a high rate of in-hospital mortality, early detection of the isolates was important to reduce their dissemination.

Risk factors for carbapenem-resistant Gram-negative bacterial infections: a systematic review

BACKGROUND

Rapid and widespread increases in carbapenem resistance (CR) necessitate identification of risk factors to guide appropriate interventions.

OBJECTIVES

We aimed to identify risk factors for CR Gram-negative infection through a systematic literature review.

DATA SOURCES

We searched MEDLINE (via OvidSP and PubMed) and Embase (via OvidSP) databases and the Cochrane Central Register of Controlled Trials.

STUDY ELIGIBILITY CRITERIA

Prospective or retrospective cohort and case-control studies reporting quantitative data on risk factors associated with infections due to CR Gram-negative pathogens in hospitalized patients were eligible.

PARTICIPANTS

Studies included hospitalized patients with CR infection caused by Gram-negative bacterial pathogens (Enterobacterales and non-fermenters).

METHODS

Searches were conducted in January 2018/December 2019 to identify studies published since 2007. Risk factor data were extracted and grouped by factor. The primary metric was proportion of studies reporting a significant association with CR infection for each factor.

RESULTS

In total, 92 studies were identified. Risk factors most frequently reported as significantly associated with CR infection (>10 studies) were previous antibiotic use (91.1%; 72/79 studies); previous carbapenem use (82.6%; 57/69); previous colonization (72.7%; 8/11); mechanical ventilation (66.7%; 36/54); previous intensive care unit stay (64.4%; 38/59); dialysis (61.1%; 11/18); catheter (58.0%; 40/69); length of stay in hospital (54.5%; 30/55); comorbidities (52.7%; 39/74); APACHE II (51.7%; 15/29); and intubation (51.4%; 18/35). Risk factors were mostly consistent across different species and sites of infection.

CONCLUSIONS

Several variables, particularly previous antibiotic use, are strong risk factors for CR infection. Interventions to mitigate against CR infection should target these factors.

Comprehensive, multisystem, mechanical decolonization of Vancomycin-Resistant Enterococcus and Carbapenem-Resistant Enterobacteriacease without the use of antibiotics

Among multidrug-resistant organisms (MDROs), Vancomycin-resistant Enterococcus (VRE), and Carbapenem-resistant Enterobacteriaceae (CRE) have become major nosocomial pathogens that are endemic worldwide. If VRE/CRE are present as colonizing organisms but do not act as pathogens, these organisms do not cause symptoms and do not require antibiotic use. However, once gastrointestinal colonization with VRE/CRE occurs, it can persist for long periods and serve as a reservoir for transmission to other patients. Therefore, a breakthrough strategy to control the spread of MDRO colonization is needed. We herein introduce decolonization method, which is a comprehensive, multisystem, consecutive mechanical MDRO decolonization protocol that does not utilize antibiotics. Our protocol included: (1).. Mechanical evacuation using a glycerin enema, (2).. Replacement of the normal gut flora using daily lactobacillus ingestion, (3).. Skin hygiene cleansing using chlorhexidine, and (4).. Environmental cleansing by changing the bed sheets and clothing every day. These steps were repeated consecutively until the patient was released from quarantine. We conducted VRE/CRE tests every week. Because our protocol was a comprehensive and multisystem decolonization protocol, the cooperation of patients and/or caregivers was essential, and family support was important for patient care. Patients were divided into VRE and CRE groups and were subdivided into success and failure groups according to decolonization status. Thirty-two patients with VRE or CRE colonization were enrolled, and our protocol was performed. A total of 20 patients (62.5%) were successfully decolonized after repeated protocols. Univariate analysis revealed that patients with younger age, higher body mass index (BMI), shorter period of MDRO isolation without trial, and higher functional status showed significantly enhanced success rates with our decolonization protocol. This study presents the decolonization effects of a comprehensive, multisystem, mechanical decolonization protocol for VRE and CRE. Most importantly, our decolonization protocol does not use antibiotics and is thus not harmful. These results suggest an active decolonization trial to be performed as early as possible in patients with VRE or CRE colonization. This simple, easy-to-apply protocol can be used as 1 of the basic treatment options for MDROs infection or colonization, regardless of whether it requires antibiotic treatment.

Comparison of four low-cost carbapenemase detection tests and a proposal of an algorithm for early detection of carbapenemase-producing Enterobacteriaceae in resource-limited settings

Rapidly progressing antibiotic resistance is a great challenge in therapy. In particular, the infections caused by carbapenem-resistant Enterobacteriaceae (CRE) are exceedingly difficult to treat. Carbapenemase production is the predominant mechanism of resistance in CRE. Early and accurate identification of carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) is extremely important for the treatment and prevention of such infections. In the present study, four phenotypic carbapenemase detection tests were compared and an algorithm was developed for rapid and cost-effective identification of CP-CRE. A total of 117 Enterobacteriaceae (54 CP-CRE, 3 non-CP-CRE, and 60 non-CRE) isolates were tested for carbapenemase production using modified Hodge test (MHT), modified carbapenem inactivation method (mCIM), Carba NP test (CNPt), and CNPt-direct test. The overall sensitivity/specificity values were 90.7%/92.1% for MHT, 100%/100% for mCIM, 75.9%/100% for CNPt, and 83.3%/100% for CNPt-direct. OXA-48-like enzymes were detected with 93.2% sensitivity by MHT and >77.3% sensitivity by two Carba NP tests. MHT could only detect half of the NDM carbapenemase producers. CNPt-direct exhibited enhanced sensitivity compared to CNPt (100% vs 25%) for detection of NDM producers. Considering these findings we propose CNPt-direct as the first test followed by mCIM for rapid detection of CP-CRE. With this algorithm >80% of the CP-CRE could be detected within 24 hours from the time the sample is received and 100% CP-CRE could be detected in day two. In conclusion, mCIM was the most sensitive assay for the identification of CP-CRE. CNPt-direct performed better than CNPt. An algorithm consisting CNPt-direct and mCIM allows rapid and reliable detection of carbapenemase production in resource-limited settings.

Fecal Carriage and Molecular Epidemiology of Carbapenem-Resistant Enterobacteriaceae from Inpatient Children in a Pediatric Hospital of Shanghai

Purpose

To determine the epidemiology characteristics of intestinal colonization of carbapenem-resistant Enterobacteriaceae (CRE) among inpatients in a pediatric hospital in China.

Methods

A retrospective study was conducted from April to December 2019. Medical records were reviewed to extract the clinical information. Antimicrobial susceptibility was performed by broth microdilution method. Drug resistance determinants and plasmid types were analyzed using polymerase chain reaction (PCR) assays. Multilocus sequence typing (MLST) and Enterobacterial repetitive intergenic consensus sequences PCR (ERIC-PCR) were employed to determine the genetic relationships between strains.

Results

A total of 90 CRE strains were isolated, with a fecal carriage rate of 8.6% (90/1052), and mainly distributed in E. aerogenes (n=30), K. pneumoniae (n=25) and E. coli (n=23). More than 50% of CRE colonizers had a history of invasive procedures and antibiotic exposures. As high as 91.1% (82/90) of CRE isolates carried carbapenemase genes, with bla_NDM-5 (n=56) being the most common, and mainly found in E. aerogenes (51.8%, 29/56) and E. coli (32.1%, 18/56) isolates, which primarily belonged to ST4 (100%, 29/29) and ST692 (55.6%, 10/18), respectively. Followed by bla_KPC-2 (n=12), and all found in K. pneumoniae ST11 isolates. Other carbapenemase genes including bla_NDM-1, bla_IMP-4 and bla_IMP-26. Meanwhile, ESBL genes (bla_CTX-M, bla_TEM-1 and bla_SHV) and AmpC genes (bla_DHA-1 and bla_EBC) were also detected. All CRE isolates showed high resistance to cephalosporins and carbapenemases (97.8%-100.0%) but remained susceptible to tigecycline (98.9%). IncX3 was a major plasmid type in NDM-containing strains (91.3%), and 91.7% of KPC-2-producing K. pneumoniae harboring IncFII and IncFIB plasmids. The ERIC-PCR revealed that several strains with identical STs were genetically similar.

Conclusion

This study revealed a major intestinal colonization of ST4 NDM-5 E. aerogenes, ST11 KPC-2 K. pneumoniae and ST692 NDM-5 E. coli strains among inpatients in a pediatric hospital. Infection control measures should be implemented immediately to prevent the spread of these strains in clinical settings.

Anti-infective treatment of purulent meningitis caused by carbapenem-resistant Klebsiella pneumoniae in a newborn: a case report

The widespread use of carbapenems has caused a notable spread of carbapenem-resistant Klebsiella pneumoniae (CRKP). The incidence of CRKP-associated infections is rising significantly in neonatal intensive care units (NICUs), which poses a grave challenge to clinical treatment. This paper is to highlight the drug treatment of CRKP with purulent meningitis in children and explore the safety of levofloxacin in children. We retrospectively analyzed the clinical data of combination therapy with levofloxacin and aztreonam in a newborn with purulent meningitis caused by CRKP. As clinical pharmacists, we evaluated the risks and benefits of quinolones for anti-infective treatment in newborns, helped clinicians adjust the anti-infective protocol of levofloxacin combined with aztreonam and provided pharmaceutical care throughout the course of treatment. In the end, the child had no fever, no dyspnea, and no obvious abnormalities in brain color Doppler ultrasound. The intracranial infection was finally controlled, and the child improved and was discharged, with no apparent neurological, skeletal, joint, tendon, or cardiac adverse events. For newborns with CRKP-associated purulent meningitis, fluoroquinolones combined with other drugs such as polymyxin, tigecycline, aminoglycosides, minocycline, that Klebsiella pneumoniae is susceptible to (when no safe and effective anti-infective alternatives are available) can reduce the mortality rate of newborns with purulent meningitis caused by carbapenem-resistant gram-negative bacteria. We analyzed the drug resistance mechanisms of CRKP, the selection of antibiotic agents, the safety of quinolones in children, the permeability of the blood-brain barrier to quinolones, and the selection of the quinolone dose. Personalized combination therapy improves treatment outcomes and reduces adverse reactions, especially in patients with resistant bacteria infection.

Epidemiologic and Microbiologic Characteristics of Hospitalized Patients Co-colonized With Multiple Species of Carbapenem-Resistant Enterobacteriaceae in the United States

We describe the epidemiologic and microbiologic characteristics of patients co-colonized with different species of carbapenem-resistant Enterobacteriaceae (CRE) from 5 hospitals in 4 states. Twenty-eight of 313 patients (8.9%) were co-colonized with at least 2 different CRE species. Different species within the same patient showed identical mechanism resistance in 18/28 (64%) cases.

Clinical and Microbiological Analysis of Risk Factors for Mortality in Patients with Carbapenem-Resistant Enterobacteriaceae Bacteremia

OBJECTIVES

The aims of this study were to identify whether the site of acquisition or the underlying carbapenem-resistant Enterobacteriaceae (CRE) resistance mechanism was associated with clinical outcomes, and to evaluate risk factors for 14-day mortality in patients with CRE bacteremia.

MATERIALS AND METHODS

A retrospective cohort study was conducted at a 2700-bed tertiary center. All adult patients with monomicrobial carbapenem-resistant Escherichia coli or Klebsiella pneumoniae bacteremia from 2011 to 2018 were included. All blood isolates collected were tested with a modified carbapenem inactivation method for phenotypic detection of carbapenemase.

RESULTS

Of 133 patients with monomicrobial CRE bacteremia, 63 (47.4%) were infected with carbapenemase-producing CRE (CP-CRE), and 70 (52.6%) with non-CP-CRE. Patients with community-onset infection (COI) were more likely to present with biliary or urinary tract infections, less likely to have ineradicable or non-eradicated foci and to receive appropriate empirical therapy, and marginally more likely to have CP-CRE compared with those with hospital-acquired infection (HAI). However, 14-day mortality was significantly lower in COI than HAI (7% vs 29%, P = 0.01). Patients who died were more likely to have had a higher APACHE II score, ineradicable or non-eradicated foci, and a lower chance of having received appropriate antibiotic treatment. Multivariate analysis revealed that HAI, high APACHE II score, and inappropriate antibiotic treatment were independent risk factors for mortality. Carbapenemase production did not affect mortality.

CONCLUSIONS

The results of this study indicate that timely, appropriate treatment is essential for managing CRE bacteremia, regardless of carbapenemase production, particularly in critically ill patients with hospital-acquired bacteremia.

Antibiotic resistance and sensitivity pattern of Metallo-β-Lactamase Producing Gram-Negative Bacilli in ventilator-associated pneumonia in the intensive care unit of a public medical school hospital in Bangladesh

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in intensive care units (ICU), accounting for 25% of all ICU infections. Antimicrobial resistance is increasing and becoming a significant health problem worldwide, increasing hospital length of stay, mortality and costs. Identifying antibiotic resistance patterns in VAP is important as this can cause outbreaks in ICUs. To date, there have been limited studies assessing this in Bangladesh. Consequently, the primary objective of this research was to study the species of bacterial growth and to determine the antibiotic resistance patterns of Metallo-β-Lactamase (MBL) producing gram-negative bacilli among ICU patients with VAP in a public medical school hospital, Bangladesh. In addition, identify the factors associated with a positive culture to provide future guidance.

METHOD

Cross-sectional study performed in the Chattogram Medical College Hospital, Bangladesh. Mueller Hinton agar plates were used for antibiotic sensitivity testing by the Kirby-Buer disc diffusion test.

RESULTS

Among 105 clinically suspected VAP cases, qualitative cultures were positive in 95 (90%) of them. The most common bacteria identified were Acinetobacter spp. (43.2%), Klebsiella spp. (20%) and Pseudomonas spp. (18.9%). A positive culture was not associated with patients' age or gender. Among 41 isolated Acinetobacter spp., 38 (92.7%) were resistant to gentamicin followed by 36 (87.8%) to ceftriaxone. Among 24 isolated Klebsiella spp., 22 (83.3%) were resistant to ceftriaxone. Among 18 isolated Pseudomonas spp., 16 (88.8%) were resistant to ciprofloxacin, and 13 (72.2%) were resistant to ceftriaxone. Among nine isolated E. coli, all were resistant to ceftriaxone and ciprofloxacin. All four Proteus spp. (100%) isolated were resistant to ciprofloxacin. Additionally, phenotype MBL producing was 65.22% and genotype was 45.65% among imipenem resistant pathogens. Imipenem resistant pathogens were sensitive to amoxyclav, amikacin¸ azithromycin, ceftazidime, ceftriaxone, colistin and gentamycin.

CONCLUSION

A positive culture was detected in 90% of VAP patients, but it was not associated with the patients' age and gender. The most common bacteria identified were Acinetobacter spp., Klebsiella spp. and Pseudomonas spp., where the majority of these were resistant to ceftriaxone. The results are being used to provide future guidance on the empiric management of VAP in this hospital.

Distribution of pathogenic bacteria in lower respiratory tract infection in lung cancer patients after chemotherapy and analysis of integron resistance genes in respiratory tract isolates of uninfected patients

Background

We studied the distribution of pathogenic bacteria in lower respiratory tract infection in lung cancer patients after chemotherapy and analyzed the integron resistance genes in respiratory tract isolates of uninfected patients.

Methods

Retrospective analysis was used to select sputum samples from 400 lung cancer patients after chemotherapy admitted in Fuyang People’s Hospital from July 2017 to July 2019. Culture, isolation and identification of strains were conducted in accordance with the national clinical examination operating procedures.

Results

A total of 134 strains were identified. In 120 patients with pulmonary infection, 114 strains were cultured. Twenty strains of klebsiella pneumoniae were cultured in 280 patients without pulmonary infection. Among the 134 strains, the detection rate of gram-negative bacteria was 79.10%. The first four strains were Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Haemophilus influenzae. The gram-positive bacteria detection rate was 4.47%, mainly Staphylococcus aureus and Streptococcus. The fungus detection rate was 16.42%. The drug sensitivity results showed that the resistance rate of gram-negative bacillus to penicillin and cephalosporin was higher, and were more sensitive to carbapenem, piperacillin tazobactam and cefoperazone sulbactam. Gram-positive cocci were resistant to penicillin, macrolide and clindamycin, and sensitive to linezolid, vancomycin and rifampicin. All strains of fungal culture were candida albicans, which were sensitive to common antifungal drugs. Among the 20 strains of klebsiella pneumoniae cultured in sputum specimens of non-infected patients with lung cancer undergoing chemotherapy, 2 strains were integron-positive strains, and all of them were class I integrons.

Conclusions

Lung cancer patients after chemotherapy have a high resistance to commonly used antimicrobial drugs, so it is necessary to detect the resistance of pathogenic microorganisms in clinical practice. The strains carried by patients with lung cancer without pulmonary infection during chemotherapy can isolate type I integrons, suggesting that the spread of drug resistance at gene level should be closely detected.

Management of infections caused by WHO critical priority Gram-negative pathogens in Arab countries of the Middle East: a consensus paper

Antimicrobial resistance is an important global issue that impacts the efficacy of established antimicrobial therapy. This is true globally and within the Arab countries of the Middle East, where a range of key Gram-negative pathogens pose challenges to effective therapy. There is a need to establish effective treatment recommendations for this region given specific challenges to antimicrobial therapy, including variations in the availability of antimicrobials, infrastructure and specialist expertise. This consensus provides regional recommendations for the first-line treatment of hospitalized patients with serious infections caused by World Health Organization critical priority Gram-negative pathogens Acinetobacter baumannii and Pseudomonas aeruginosa resistant to carbapenems, and Enterobacteriaceae resistant to carbapenems and third-generation cephalosporins. A working group comprising experts in infectious disease across the region was assembled to review contemporary literature and provide additional consensus on the treatment of key pathogens. Detailed therapeutic recommendations are formulated for these pathogens with a focus on bacteraemia, nosocomial pneumonia, urinary tract infections, skin and soft tissue infections, and intra-abdominal infections. First-line treatment options are provided, along with alternative agents that may be used where variations in antimicrobial availability exist or where local preferences and resistance patterns should be considered. These recommendations take into consideration the diverse social and healthcare structures of the Arab countries of the Middle East, meeting a need that is not filled by international guidelines. There is a need for these recommendations to be updated continually to reflect changes in antimicrobial resistance in the region, as well as drug availability and emerging data from clinical trials.