Risk factors and clinical outcomes for carbapenem-resistant Enterobacteriaceae nosocomial infections

Molecular epidemiology and risk factors for carbapenem-resistant Enterobacteriaceae infections during 2020-2021 in Northwest China

OBJECTIVES

Severe infection caused by Carbapenem-resistant Enterobacteriaceae (CRE) is a challenge for clinical anti-infective therapy, and clinical intervention to improve control of CRE is of great significance. The study aims to determine the molecular epidemiology and risk factors of CRE infections to provide evidence for effective control of nosocomial infection in patients with CRE.

METHODS

A total of 192 non-repetitive CRE strains were collected from January 2020 to December 2021 in Northwest China. To explore the risk factors of CRE infection by univariate and Logistic regression analysis, 1:1 case-control study was used to select Carbapenem sensitive Enterobacteriaceae (CSE) infection patients at the same period as the control group.

RESULTS

Among the 192 CRE strains, the most common isolates included Klebsiella pneumoniae (Kpn) and Enterobacter cloacae (Ecl). The CRE strain showed the lowest rate of resistance to amikacin at 58.3. 185 CRE strains carried carbapenemase resistance genes of concern in this study. KPC-2 (n=94) was the most common carbapenemase, followed by NDM-1 (n=69), NDM-5 (n=22) and IMP-4 (n=5). OXA-48 and VIM were not detected. And KPC-2 was the most common in all strains. Logistic regression analysis implicated days of invasive ventilator-assisted ventilation (OR=1.452; 95 % CI 1.250～1.686), antibiotic combination therapy (OR=2.149; 95 % CI 1.128～4.094), hypoalbuminemia (OR=6.137; 95 % CI 3.161～11.913), history of immunosuppressant use (OR=25.815; 95 % CI 6.821～97.706) and days of hospitalization (OR=1.020; 95 % CI 1.006～1.035) as independent risk factors associated with CRE infection. Age (OR=0.963; 95% CI 0.943～0.984) and history of hormone use (OR=0.119; 95 % CI 0.028～0.504) were protective factors for CRE infection (P < 0.05).

CONCLUSIONS

The resistance of commonly used antibiotics in clinical is severe, and CRE strains mainly carry KPC-2 and NDM-1. Multiple risk factors for CRE infection and their control can effectively prevent the spread of CRE.

Factors associated with non-carbapenemase mediated carbapenem resistance of Gram-negative bacteria: a retrospective case-control study

Infections with carbapenemase-producing Gram-negative bacteria are related to increased morbidity and mortality, yet little is known regarding infections caused by non-beta-lactamase mediated carbapenem-resistant bacteria. Our objective was to identify risk factors for, and the clinical impact of infections caused by carbapenem-resistant carbapenemase-negative Enterobacterales and Pseudomonas aeruginosa. This retrospective matched case-control study was performed at the University Hospital of Basel, Switzerland, in 2016. We focused on other resistance mechanisms by excluding laboratory-confirmed carbapenemase-positive cases. Carbapenem resistance was set as the primary endpoint, and important risk factors were investigated by conditional logistic regression. The clinical impact of carbapenem resistance was estimated using regression models containing the resistance indicator as explanatory factor and adjusting for potential confounders. Seventy-five cases of infections with carbapenem-resistant, carbapenemase-negative bacteria were identified and matched with 75 controls with carbapenem-susceptible infections. The matched data set was well-balanced regarding age, gender, and comorbidity. Duration of prior carbapenem treatment (OR 1.15, [1.01, 1.31]) correlated with resistance to carbapenems. Our study showed that patients with carbapenem-resistant bacteria stayed 1.59 times (CI [0.81, 3.14]) longer in an ICU. The analyzed dataset did not provide evidence for strong clinical implications of resistance to carbapenems or increased mortality. The duration of prior carbapenem treatment seems to be a strong risk factor for the development of carbapenem resistance. The higher risk for a longer ICU stay could be a consequence of a carbapenem resistance. In contrast to carbapenemase-producers, the clinical impact of carbapenamase-negative, carbapenem-resistant strains may be limited. Trial registration: The study design was prospectively approved by the local Ethics Commission on 10.08.2017 (EKNZ BASEC 2017-00222).

Perinatal colonization with extended-spectrum beta-lactamase-producing and carbapenem-resistant Gram-negative bacteria: a hospital-based cohort study

BACKGROUND

Antimicrobial resistance (AMR) is a growing global health threat that contributes to substantial neonatal mortality. Bangladesh has reported some of the highest rates of AMR among bacteria causing neonatal sepsis. As AMR colonization among newborns can predispose to infection with these bacteria, we aimed to characterize the frequency of and risk factors for colonization of mothers and newborns during hospitalization for delivery.

METHODS

We enrolled pregnant women presenting for delivery to a tertiary care hospital in Faridpur, Bangladesh. We collected vaginal and rectal swabs from mothers pre- and post-delivery, rectal swabs from newborns, and swabs from the hospital environment. Swabs were plated on agars selective for extended-spectrum-beta-lactamase producing bacteria (ESBL-PB) and carbapenem-resistant bacteria (CRB). We performed logistic regression to determine factors associated with ESBL-PB/CRB colonization.

RESULTS

We enrolled 177 women and their newborns during February-October 2020. Prior to delivery, 77% of mothers were colonized with ESBL-PB and 15% with CRB. 79% of women underwent cesarean deliveries (C-section). 98% of women received antibiotics. Following delivery, 98% of mothers and 89% of newborns were colonized with ESBL-PB and 89% of mothers and 72% of newborns with CRB. Of 290 environmental samples, 77% were positive for ESBL-PB and 69% for CRB. Maternal pre-delivery colonization was associated with hospitalization during pregnancy (RR for ESBL-PB 1.24, 95% CI 1.10-1.40; CRB 2.46, 95% CI 1.39-4.37). Maternal post-delivery and newborn colonization were associated with C-section (RR for maternal CRB 1.31, 95% CI 1.08-1.59; newborn ESBL-PB 1.34, 95% CI 1.09-1.64; newborn CRB 1.73, 95% CI 1.20-2.47).

CONCLUSIONS

In this study, we observed high rates of colonization with ESBL-PB/CRB among mothers and newborns, with pre-delivery colonization linked to prior healthcare exposure. Our results demonstrate this trend may be driven by intense use of antibiotics, frequent C-sections, and a contaminated hospital environment. These findings highlight that greater attention should be given to the use of perinatal antibiotics, improved surgical stewardship for C-sections, and infection prevention practices in healthcare settings to reduce the high prevalence of colonization with AMR organisms.

Clinical Outcomes and Risk Factors for Death in Critically Ill Patients with Carbapenem-Resistant Klebsiella pneumoniae Treated with Ceftazidime-Avibactam: A Retrospective Study

Purpose

Carbapenem-Resistant Klebsiella pneumoniae (CRKP) is a significant public health threat, because it is associated with substantial morbidity and mortality. However, the risk factors associated with treatment failure of ceftazidime-avibactam (CAZ-AVI) and the need for CAZ-AVI-based combination remain unclear.

Methods

We conducted a retrospective study of critically ill patients (age: > 18 years) diagnosed with CRKP infections and treated with CAZ-AVI for at least 24 h between June 2020 and December 2022 at Henan Provincial People's Hospital.

Results

This study included a total of 103 patients who received CAZ-AVI. Of these, 91 (88.3%) patients received the standard dosage of 2.5 g every q8h, while only 20 (19.4%) received monotherapy. The Kaplan-Meier curves showed that the all-cause 30-day mortality was significantly higher among patients who experienced septic shock than those who did not. There was no significant difference in mortality between monotherapy and combination therapy. Dose reduction of CAZ-AVI was associated with a significantly increased mortality rate. Independent risk factors for the 30-day mortality included higher APACHE II score (HR: 1.084, 95% CI: 1.024-1.147, p = 0.005) and lower lymphocyte count (HR: 0.247, 95% CI: 0.093-0.655, p = 0.005). Conversely, a combination therapy regimen containing carbapenems was associated with lower mortality (HR: 0.273, 95% CI: 0.086-0.869, p = 0.028).

Conclusion

Our study suggests that CAZ-AVI provides clinical benefits in terms of survival and clinical response in critically ill patients with CRKP infection. A higher APACHE II score and lower lymphocyte count were associated with 30-day mortality, while the combination therapy regimen containing carbapenems was the only protective factor. CAZ-AVI dose reduction was associated with an increased mortality rate. Futher large-scale studies are needed to validate these findings.

Clinical, microbiological characteristics and predictors of mortality in patients with carbapenemase-producing Enterobacterales bloodstream infections: a multicentre study

Objectives

To investigate the clinical, microbiological characteristics and outcomes of patients with bloodstream infections (BSI) due to carbapenemase-producing Enterobacterales (CPE).

Methods

A multicentre retrospective observational study of patients with BSIs due to CPE admitted to six UK hospitals was conducted between 2011 and 2021. Multivariate analysis was used to identify factors predicting 30-day case fatality rate (CFR).

Results

There were 84 episodes of CPE-BSIs, 37 (44%) due to OXA-48, 35 (42%) to metallo-betalactamases (MBL) and 12 (14%) to KPC. 63% of patients were male with a median age of 64 years. Common organisms included Klebsiella spp. (61%), Escherichia coli (20%) and Enterobacter spp. (13%). Urinary devices were more often involved in OXA-48 BSIs (12/37; 32%) compared to infections caused by MBL and KPC (4/35; 11% and 1/12; 8%; P = 0.046). In contrast, central venous catheters were more frequently present in KPC-BSIs (10/12; 92%) compared with OXA-48 and MBL (11/37; 30% and 20/35; 57%; P = 0.002). Effective definitive antimicrobials were received by 72/84 (86%) patients, comprising monotherapy (32/72; 44%) or combination therapy (40/72; 56%). 30-day case fatality rate (CFR) was 38%. Sepsis or septic shock was associated with death [OR 3.81 (CI 1.19-12.14), P = 0.024].

Conclusion

Strategies targeting high-risk patients and adherence to infection prevention bundles for urinary devices and central venous catheters can reduce OXA-48 and KPC-BSIs. Early recognition and management of severe sepsis, prompt initiation of appropriate antimicrobial therapy and development of novel antimicrobials are crucial to mitigate the high CFR associated with CPE-BSIs.

Epidemiological characteristics of New Delhi Metallo-β-Lactamase-producing Enterobacteriaceae in the Fourth hospital of Hebei Medical University

The epidemiological characteristics of New Delhi Metallo-β-Lactamase-Producing (NDM) Enterobacteriaceae were analyzed to provide theoretical support for clarifying the distribution characteristics of carbapenem-resistant Enterobacteriaceae (CRE) in the hospital environment and early identification of susceptible patients. From January 2017 to December 2021,42 strains of NDM-producing Enterobacteriaceae were gathered from the Fourth Hospital of Hebei Medical University, primarily Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae. The micro broth dilution method combined with the Kirby-Bauer method was used to determine the minimal inhibitory concentrations (MICs) of antibiotics. The carbapenem phenotype was detected by the modified carbapenem inactivation method (mCIM) and EDTA carbapenem inactivation method (eCIM). Carbapenem genotypes were detected by colloidal gold immunochromatography and real-time fluorescence PCR. The results of antimicrobial susceptibility testing showed that all NDM-producing Enterobacteriaceae were multiple antibiotic resistant, but the sensitivity rate to amikacin was high. Invasive surgery prior to culture, the use of excessive amounts of different antibiotics, the use of glucocorticoids, and ICU hospitalization were clinical characteristics of NDM-producing Enterobacteriaceae infection. Molecular typing of NDM-producing Escherichia coli and Klebsiella pneumoniae was carried out by Multilocus Sequence Typing (MLST), and the phylogenetic trees were constructed. Eight sequence types (STs) and two NDM variants were detected in 11 strains of Klebsiella pneumoniae, primarily ST17, and NDM-1. A total of 8 STs and 4 NDM variants were detected in 16 strains of Escherichia coli, mainly ST410, ST167, and NDM-5. For high-risk patients who have CRE infection, CRE screening should be done as soon as feasible to adopt prompt and efficient intervention measures to prevent outbreaks in the hospital.

Ceftazidime-Avibactam (C/A) Resistant, Meropenem Sensitive KPC-Producing Klebsiella pneumoniae in ICU Setting: We Are What We Are Treated with?

The continuous spread of carbapenem-resistant Klebsiella pneumoniae (CP-Kp) strains presents a severe challenge to the healthcare system due to limited therapeutic options and high mortality. Since its availability, ceftazidime/avibactam (C/A) has become a first-line option against KPC-Kp, but C/A-resistant strains have been reported increasingly, especially with pneumonia or prior suboptimal blood exposure to C/A treatment. A retrospective, observational study was conducted with all patients admitted to the Intensive Care Unit (ICU) dedicated to COVID-19 patients at the City of Health & Sciences in Turin, between 1 May 2021 and 31 January 2022, with the primary endpoint to study strains with resistance to C/A, and secondly to describe the characteristics of this population, with or without previous exposure to C/A. Seventeen patients with colonization or invasive infection due to Klebsiella pneumoniae, C/A resistance, and susceptibility to meropenem (MIC = 2 µg/L) were included; the bla_KPC genotype was detected in all isolates revealing D179Y mutation in the bla_KPC-2 (bla_KPC-33) gene. Cluster analysis showed that 16 out of the 17 C/A-resistant KPC-Kp isolates belonged to a single clone. Thirteen strains (76.5%) were isolated in a 60-day period. Only some patients had a previous infection with non-mutant KPC at other sites (5; 29.4%). Eight patients (47.1%) underwent previous large-spectrum antibiotic treatment, and four patients (23.5%) had prior treatment with C/A. The secondary spread of the D179Y mutation in the bla_KPC-2 during the COVID-19 pandemic needs to be addressed constantly by an interdisciplinary interaction between microbiologists, infection control personnel, clinicians, and infectious diseases consultants to properly diagnose and treat patients.

The shared NDM-positive strains in the hospital and connecting aquatic environments

The spread of antibiotic-resistant priority pathogens outside hospital settings is, both, a significant public health concern and an environmental problem. In recent years, New Delhi Metallo-β-lactamase (NDM)-positive strains have caused nosocomial infections with high mortality and poor prognosis worldwide. Our study investigated the links of NDM-positive strains between the hospital and the connecting river system in Jinan city, Eastern China by using NDM-producing Escherichia coli (NDM-EC) as an indicator via whole genome sequencing. Thirteen NDM-EC isolates were detected from 187 river water and sediment samples, while 9 isolates were identified from patients at the local hospital. All NDM-EC isolates were resistant to imipenem, meropenem, cefotaxime, cefoxitin, ampicillin, tetracycline, fosfomycin, piperacillin-tazobactam. The bla_NDM-5 (n = 20) and bla_NDM-9 (n = 2) genes were identified, which were predominantly on IncX3 plasmids (n = 13), followed by IncFII plasmids (n = 5) and IncFIA plasmids (n = 2). Conjugation experiments showed that 21 isolates could transfer NDM-harboring plasmids. The well-conserved bla_NDM-5 genetic environment (ISAba125-bla_NDM-5/9-ble_MBL-trpF-dsbD-IS26) of these plasmids suggested a common genetic origin. Nine sequence types (STs) were detected, including three international high-risk clones ST167 (n = 8), ST410 (n = 1), and ST617 (n = 1). Phylogenetic analysis showed ST167 E. coli from the river was genotypically related to clinical isolates recovered from patients. Furthermore, ST167 isolates showed high genetic similarities with other clinical strains from geographically distinct regions. The genetic concordance between isolates from different sampling sites in the same river (ST218 clone), and different rivers (ST448 clone) raises concerns regarding the rapid dissemination of NDM-EC in the aquatic environment. The emergence and spread of the clinically relevant NDM-positive strains, especially for E. coli ST167 clone, an international high-risk clone associated with multi-resistance and virulence capacity, within and between the hospital and aquatic environments were elucidated, highlighting the need for attention and action.

Clinical characteristics and outcomes of carbapenem-resistant Enterobacterales bacteremia in pediatric patients

BACKGROUND/PURPOSE

Clinical data on carbapenem-resistant Enterobacterales (CRE) bacteremia in the pediatric population are limited. This study investigated the clinical characteristics and outcomes of pediatric CRE bacteremia.

METHODS

Clinical data on bacteremia caused by carbapenem-susceptible and carbapenem-resistant Enterobacterales, including Escherichia coli, Klebsiella spp., Enterobacter spp., Serratia marcescens, Proteus mirabilis, Citrobacter spp., and Morganella spp., in pediatric patients from a children's hospital in Taiwan were retrospectively retrieved and analyzed.

RESULTS

From January 2013 to December 2021, 471 clinical isolates of Enterobacterales bacteremia were identified in 451 episodes from 379 pediatric patients. Among all the isolates, the predominant species were E. coli (199/471, 42.2%), Klebsiella spp. (168/471, 35.6%), and Enterobacter spp. (59/471, 12.5%), with carbapenem-resistance rates of 1.5%, 11.9%, and 25.0%, respectively. Overall, 40 (8.4%) showed a carbapenem resistance phenotype. Patients' all-cause mortality rate at 14 days was significantly higher in CRE bacteremia episodes than non-CRE ones (12.5% vs. 3.6%, p < 0.05). The predicting factor of a CRE bacteremia episode was the causative agent of Enterobacter spp. (adjusted OR of 2.551, CI 1.073-6.066, p < 0.05) and ESBL-producing phenotype (adjusted OR 14.268, CI 5.120-39.762, p < 0.001).

CONCLUSION

Bloodstream infections caused by CRE are associated with a higher mortality rate in the pediatric population. Attention must be paid to preventing and managing pediatric patients with CRE infections.

Molecular Characterization and Epidemiology of Carbapenem-Resistant Enterobacteriaceae Isolated from Pediatric Patients in Guangzhou, Southern China

Background

Carbapenem-resistant Enterobacteriaceae (CRE) are spreading worldwide, posing a serious public health concern. However, the data on CRE strains that cause infections in children in Guangzhou remain limited. Therefore, this study aimed to investigate the epidemiology of CRE, drug resistance, and resistance mechanisms in children in Guangzhou, Southern China.

Methods

In total, 54 nonrepetitive CRE strains were collected in pediatric patients at three centers in Guangzhou, Southern China, from January 2016 to August 2018. CRE isolates were used for further studies on antimicrobial susceptibility, the modified Hodge test (MHT), the modified carbapenem inactivation method (mCIM), and drug resistance genes. Multilocus sequence typing (MLST) was used to elucidate the molecular epidemiology of K. pneumoniae.

Results

The isolated CRE strains include 34 K. pneumoniae (63.0%), 10 E. coli (18.5%), 4 Enterobacter cloacae (7.4%), and 6 Proteus mirabilis (11.1%) strains. The strains were isolated mainly from the blood (31.5%, n = 17), sputum (31.5%, n = 17), and urine (16.7%, n = 9). All CRE isolates were highly resistant to the third- or fourth-generation cephalosporins, carbapenems, and β-lactam + β-lactamase inhibitors (94.4%-96.3%). In addition, the resistance rates to amikacin, ciprofloxacin, levofloxacin, tigecycline, and colistin were 5.6%, 14.8%, 16.7%, 9.3%, and 0%, respectively. Carbapenemase was detected in 35 (64.8%) of the CRE isolates. The most dominant carbapenemase gene was bla _NDM (n = 17, 48.6%), followed by bla _IMP (n = 13, 37.1%) and bla _OXA-23 (n = 4, 11.4%). Other carbapenemase genes (bla _KPC, bla _sim, bla _Aim, bla _GES, bla _Gim, bla _OXA-2 , and bla _OXA-48 ) and the mcr-1 gene were not detected. MLST analysis showed high diversity among the K. pneumoniae, and ST45 (11.7%, 4/34) was the dominant sequence type.

Conclusion

This study revealed bla _NDM was the most dominant carbapenemase gene in children in Guangzhou. Infection control measures need to be taken for the prevention and treatment of CRE infections.

Magnitude and antimicrobial susceptibility profiles of Gram-Negative bacterial isolates among patients suspected of urinary tract infections in Arba Minch General Hospital, southern Ethiopia

The emergence of drug-resistant Gram-negative bacterial uropathogens poses a grave threat worldwide, howbeit studies on their magnitude are limited in most African countries, including Ethiopia. Therefore, measuring the extent of their drug resistance is essential for developing strategies to confine the spread. A cross-sectional study was conducted at title hospital from 01 June to 31 August 2020. Midstream urine specimens were collected and inoculated onto MacConkey agar. Positive urine cultures showing significant bacteriuria as per the Kass count (>105 CFU/mL) were further subjected to biochemical tests to identify the type of uropathogens. Antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion technique, and potential carbapenemase producers were phenotypically determined by the modified carbapenem inactivation method as per the CLSI guidelines. Data were analyzed using SPSS version 26; P-value <0.05 was considered statistically significant. Totally, 422 patients were included, and the majority were females (54.7%). The prevalence of carbapenem-resistant Gram-negative uropathogens was 12.9%, and 64.7% of them were carbapenemase producers. Klebsiella pneumoniae (n = 5) was the predominant carbapenemase producer, followed by Pseudomonas aeruginosa (n = 4). Consumption of antibiotics prior to six months of commencement of the study, the presence of chronic diseases and hospitalizations were statistically associated with UTI caused by carbapenem-resistant Gram-negative uropathogens. Carbapenemase producers were resistant to most of the antibiotics tested. Our findings highlight the need for periodic regional bacteriological surveillance programs to guide empirical antibiotic therapy of UTI.

Treatments and Predictors of Mortality for Carbapenem-Resistant Gram-Negative Bacilli Infections in Malaysia: A Retrospective Cohort Study

This study evaluated the treatments, mortality rate and patient-related factors associated with mortality. This is a retrospective study involving hospitalised patients with infections caused by carbapenem-resistant Gram-negative bacilli (CR-GNB) in a tertiary hospital in Malaysia from January 2018 to June 2020. A clinical pharmacist reviewed patients' electronic records and collected the data according to a pre-designed form. Data were analysed using both descriptive and inferential tests. The study included 145 patients with CR-GNB infections including 77, 40 and 28 Acinetobacter baumannii, enterobacteriaceae and Pseudomonas aeruginosa, respectively. The mean age was 57.9 ± 15.8 years. Pneumonia (40.7%) and bacteremia (25.5%) were the most common infections. Meropenem (24.7%) and piperacillin-tazobactam (20.4%) were the most commonly used empiric antibiotics while colistin (63.3%) and amikacin (8.3%) were the most common definitive antibiotics. The mean duration before active antibiotics was 4.6 ± 3.3 days. Overall, the in-hospital mortality rate was 41.4%. Multivariate logistic regression analysis showed that intensive care unit (ICU) admission (adjusted odds ratio (AOR): 5.201; 95% confidence interval (CI): 1.603-16.872; p = 0.006), sepsis/septic shock (AOR: 3.430; 95% CI: 1.021-11.522; p = 0.049) and elevated serum creatinine (AOR: 2.752; 95% CI: 1.005-7.536; p = 0.049) were independently associated with mortality. The mortality rate among patients with CR-GNB infection is high. A high rate of inappropriate antibiotic use was observed, including combination antibiotic therapy and delays in starting active antibiotics. Mortality was significantly associated with ICU admission, sepsis/septic shock and elevated serum creatinine.

Novel insights related to the rise of KPC-producing Enterobacter cloacae complex strains within the nosocomial niche

According to the World Health Organization, carbapenem-resistant Enterobacteriaceae (CRE) belong to the highest priority group for the development of new antibiotics. Argentina-WHONET data showed that Gram-negative resistance frequencies to imipenem have been increasing since 2010 mostly in two CRE bacteria: Klebsiella pneumoniae and Enterobacter cloacae Complex (ECC). This scenario is mirrored in our hospital. It is known that K. pneumoniae and the ECC coexist in the human body, but little is known about the outcome of these species producing KPC, and colonizing or infecting a patient. We aimed to contribute to the understanding of the rise of the ECC in Argentina, taking as a biological model both a patient colonized with two KPC-producing strains (one Enterobacter hormaechei and one K. pneumoniae) and in vitro competition assays with prevalent KPC-producing ECC (KPC-ECC) versus KPC-producing K. pneumoniae (KPC-Kp) high-risk clones from our institution. A KPC-producing E. hormaechei and later a KPC-Kp strain that colonized a patient shared an identical novel conjugative IncM1 plasmid harboring blaKPC-2. In addition, a total of 19 KPC-ECC and 58 KPC-Kp strains isolated from nosocomial infections revealed that high-risk clones KPC-ECC ST66 and ST78 as well as KPC-Kp ST11 and ST258 were prevalent and selected for competition assays. The competition assays with KCP-ECC ST45, ST66, and ST78 versus KPC-Kp ST11, ST18, and ST258 strains analyzed here showed no statistically significant difference. These assays evidenced that high-risk clones of KPC-ECC and KPC-Kp can coexist in the same hospital environment including the same patient, which explains from an ecological point of view that both species can exchange and share plasmids. These findings offer hints to explain the worldwide rise of KPC-ECC strains based on the ability of some pandemic clones to compete and occupy a certain niche. Taken together, the presence of the same new plasmid and the fitness results that showed that both strains can coexist within the same patient suggest that horizontal genetic transfer of blaKPC-2 within the patient cannot be ruled out. These findings highlight the constant interaction that these two species can keep in the hospital environment, which, in turn, can be related to the spread of KPC.

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.

The burden of carbapenem-resistant Enterobacterales infection in a large Thai tertiary care hospital

Background: Carbapenem-resistant Enterobacterales (CRE) are resistant to several other classes of antimicrobials, reducing treatment options and increasing mortality. We studied the clinical characteristics and burden of hospitalized adult patients with CRE infections in a setting where treatment options are limited.

Methods: A retrospective cohort study included adult inpatients between January 2015–December 2019 at Siriraj Hospital in Bangkok, Thailand. Clinical and microbiological data were reviewed.

Results: Of 420 patients with CRE infections, the mean age was 65.00 ± 18.89 years, 192 (45.72%) were male, and 112 (26.90%) were critically ill. Three hundred and eighty (90.48%) had Klebsiella pneumoniae, and 40 (9.52%) had Escherichia coli infections. The mean APACHE II score was 14.27 ± 6.36. Nearly half had previous hospitalizations (48.81%), 41.2% received antimicrobials, and 88.1% had undergone medical procedures before the onset of infection. The median time of onset of CRE infection was 16 days after admission. Common sites of infection were bacteremia (53.90%) and pneumonia (45.47%). Most CRE-infected patients had septic shock (63.10%) and Gram-negative co-infections (62.85%). Colistin (29.95%) and non-colistin (12.91%) monotherapies, and colistin-based (44.78%) and non-colistin-based (12.36%) combination therapies were the best available antimicrobial therapies (BAAT). The median length of hospitalization was 31 days, and the median hospitalization cost was US$10,435. The in-hospital mortality rate was 68.33%. Septic shock [adjusted odds ratio (aOR) 10.73, 5.65–20.42, p <0 .001], coinfection (aOR 2.43, 1.32–4.47, p = 0.004), mechanical ventilation (aOR 2.33, 1.24–4.36, p = 0.009), and a high SOFA score at onset (aOR 1.18, 1.07–1.30, p <0 .001) were associated with mortality.

Conclusion: CRE infection increases mortality, hospital stays, and healthcare costs. A colistin-based regimen was the BAAT in this study. Therefore, newer antimicrobial agents are urgently needed.

Carbapenem-Resistant Enterobacteriaceae: A Retrospective Review of Presentation, Treatment, and Clinical Outcomes in a Tertiary Care Referral Hospital

Background: Carbapenem-resistant Enterobacteriaceae (CRE) is an emerging infectious threat with an increasing incidence locally and worldwide. It carries a high morbidity and mortality; focusing on this topic should be a priority in clinical research as local data are not widely available. The objective of this study is to describe the presentation, risk factors, treatment pattern and clinical outcomes associated with CRE infections.

Methods: We conducted a cross-sectional retrospective study in a single center tertiary referral hospital. We included adult patients above 18 years of age with infection due to CRE between January 1, 2018, to December 30, 2019. 

Results: During this period, 76 cases were studied. The mean age of the cases was 54 years. The majority were immunosuppressed and admitted to the intensive care unit. The most frequent risk factors associated with CRE infection among study subjects included prior antibiotics in the preceding three months and prior hospital admission in the last one year. Klebsiella pneumoniae (77%) represented the most isolated organism. All-cause intensive care unit and in-hospital mortality were significantly higher among patients with pneumonia and bacteremia. 

Conclusions: CRE infections are associated with higher morbidity and mortality specifically in patients who presented with pneumonia and bacteremia. High resistance rate and limited treatment options have made a great variability in the clinical practice. Appropriate definitive treatment of CRE infections, strict infection control measures, and antimicrobial stewardship program activation are essential.

A Retrospective Study of Risk Factors, Mortality, and Treatment Outcomes for Infections with Carbapenemase-Producing Enterobacterales in a Tertiary Hospital in Havana, Cuba

(1) Background: The spread of carbapenem-resistant Enterobacterales in hospitals constitutes an important epidemiological and therapeutic problem that especially affects vulnerable patients such as perioperative patients. (2) Methods: We conducted a descriptive, observational, retrospective case-control study of patients infected with carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) and carbapenem-susceptible Enterobacterales during the perioperative period in a tertiary hospital. (3) Results: Metallo-β-lactamase was detected in all 124 CRE isolates, with NDM-type carbapenemase being dominant, while 3 isolates coproduced KPC-type enzyme and showed high resistance rates against all antibiotics except colistin (25.2%). By analyzing the risk factors for infection, steroid use (OR: 3.22, p < 0.01), prior use of two or more antibiotics (OR: 4.04, p = 0.01), prior use of broad-spectrum cephalosporins (OR: 2.40, p = 0.04), and prior use of carbapenem (OR: 4.77, p = 0.03) were found to be independent risk factors for CP-CRE infection. In addition, in this study, we observed that the clinical outcomes of bloodstream infections and pneumonia associated with CP-CRE posed higher mortality risks. However, by analyzing the associations between treatment options and mortality, it was found that, in bloodstream infections caused by CP-CRE, colistin-based regimens showed a significant advantage (PR = 0.40, p = 0.03). (4) Conclusions: High mortality is associated with nosocomial infections in the perioperative period caused by carbapenemase-producing Enterobacterales, the dissemination of which in health care settings in Cuba remains a public health challenge.

Mortality Risk Factors and Prognostic Analysis of Patients with Multi-Drug Resistant Enterobacterales Infection

Background

The data from the China Network Antibacterial Surveillance Center (http://www.chinets.com) showed that the prevalence of Escherichia coli (E. coli), Klebsiella pneumoniae (KP), and Enterobacter cloacae (ecl), was 18.96%, 14.12%, and 2.74% in 2022, respectively. The resistance rates of E. coli and KP to 3rd or 4th generation cephalosporins were 51.7% and 22.1%, to carbapenems was 1.7% and 3.9%, to quinolones was 55.9% in Shanxi. The generation of extended-spectrum beta-lactamases (ESBLs) is a major mechanism resulting in drug resistance in Enterobacterales. To determine the mortality risk factors of multi-drug resistant Enterobacterales (MDRE) and multi-drug resistant Klebsiella pneumoniae (MDR-KP) infection.

Methods

91 MDR strains from 91 patients were collected from 2015 to 2019 in the second hospital of Shanxi Medical University. The mortality risk factors for the MDRE infections and clinical outcomes were analyzed by univariable and multivariable analysis. The independent predictors of 30-day mortality were analyzed through the Cox regression analysis including the variables with a value <0.2.

Results

The majority of patients were admitted to ICUs. Pulmonary infection was a major infection (43.96%, 40/91). Thirty-three (36.26%, 33/91) strains of MDR-KP were only detected in 2018. The proportion of multi-drug resistant Escherichia coli (MDR E. coli) and multi-drug resistant Enterobacter cloacae (MDR ecl) were 16.48% (15/91) and 17.58% (16/91), respectively. The presence of cerebrovascular diseases (OR, 4.046; 95%Cl, 1.434–11.418; P=0.008) and central venous catheterization (OR, 4.543; 95%Cl, 1.338–15.425; P=0.015) were associated with mortality in patients with MDRE infections. Endotracheal intubation (OR, 4.654; 95%Cl, 1.5–14.438; P=0.008) was an independent mortality risk factor for patients infected with MDR-KP strains. Patients who received aminoglycoside antibiotics (P=0.057) had a higher 30-day survival rate. The β-lactam antibiotics were the major agent in the clinic.

Conclusion

This study implies that patients with cerebrovascular diseases, central venous catheterization, and endotracheal intubation are at risk of carrying MDR isolates.

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.

Mutations in AR or SRD5A2 Genes: Clinical Findings, Endocrine Pitfalls, and Genetic Features of Children with 46,XY DSD

OBJECTIVE

Androgen insensivity syndrome (AIS) and 5α-reductase deficiency (5α-RD) present with indistinguishable phenotypes among the 46,XY disorders of sexual development (DSD) that usually necessitate molecular analyses for the definitive diagnosis in the prepubertal period. The aim was to evaluate the clinical, hormonal and genetic findings of 46,XY DSD patients who were diagnosed as AIS or 5α-RD.

METHODS

Patients diagnosed as AIS or 5α-RD according to clinical and hormonal evaluations were investigated. Sequence variants of steroid 5-α-reductase type 2 were analyzed in cases with testosterone/dihydrotestosterone (T/DHT) ratio of ≥20, whereas the androgen receptor (AR) gene was screened when the ratio was <20. Stepwise analysis of other associated genes were screened in cases with no causative variant found in initial analysis. For statistical comparisons, the group was divided into three main groups and subgroups according to their genetic diagnosis and T/DHT ratios.

RESULTS

A total of 128 DSD patients from 125 non-related families were enrolled. Birth weight SDS and gestational weeks were significantly higher in 5α-RD group than in AIS and undiagnosed groups. Completely female phenotype was higher in all subgroups of both AIS and 5α-RD patients than in the undiagnosed subgroups. In those patients with stimulated T/DHT <20 in the prepubertal period, stimulated T/DHT ratio was significantly lower in AIS than in the undiagnosed group, and higher in 5α-RD. Phenotype associated variants were detected in 24% (n=18 AIS, n=14 5α-RD) of the patients, revealing four novel AR variants (c.94G>T, p.Glu32*, c.330G>C, p.Leu110=; c.2084C>T, p.Pro695Leu, c.2585_2592delAGCTCCTG, p.(Lys862Argfs*16), of these c.330G>C with silent status remained undefined in terms of its causative effects.

CONCLUSION

T/DHT ratio is an important hormonal criterion, but in some cases, T/DHT ratio may lead to diagnostic confusion. Molecular diagnosis is important for the robust diagnosis of 46,XY DSD patients. Four novel AR variants were identified in our study.

Use of the Combined Modified Carbapenem Inactivation Method and EDTA-modified Carbapenem Inactivation Method for Detection of Carbapenemase-Producing Enterobacteriaceae Causing Ventilator-associated Respiratory Infections

There is an alarming rise in carbapenem-resistant Enterobacteriaceae (CRE) causing nosocomial infections such as ventilator-associated respiratory infections (VARIs). The use of rapid phenotypic methods for the detection and differentiation of carbapenemases elaborated by these CRE would be helpful in providing timely empirical therapeutic options for management of these infections and preventing spread of these CRE strains in hospital settings. Hence, this study aimed to detect CRE among pathogens isolated from the endotracheal secretions recieved from suspected cases of VARIs and differentiate carbapenemases elaborated by these CRE using combined phenotypic methods, such as the modified carbapenem inactivation method (mCIM) and EDTA modified CIM (eCIM). This observational study was conducted over a period of 1 year in the Department of Microbiology and the intensive care unit of a tertiary care center. Carbapenem resistance was found in 75% of Klebsiella pneumoniae isolates and 50% of Escherichia coli isolates, of which 58.4% were metallo-β-lactamases and 41.6% were serine carbapenemase producers. In conclusion, the combination of the mCIM and eCIM could be useful as an epidemiological tool and be considered essential in deciding the initial antibiotic therapy, help reduce morbidity and mortality associated with VARIs, and guide hospital infection control practices.

Risk factors for antibiotic-resistant bacteria colonisation in children with chronic complex conditions

To assess drug-resistant bacterial colonisation rates and associated risk factors in children with complex chronic conditions admitted to a national reference unit in Spain. Cross-sectional study that included all children admitted to our unit from September 2018 to July 2019. Rectal swabs were obtained to determine multidrug-resistant Gram-negative bacilli (MR-GNB) colonisation, and nasal swab to determine S. aureus and methicillin-resistant S. aureus (MRSA) colonisation. Medical records were reviewed. 100 children were included, with a median of four complex chronic conditions. Sixteen percent had S. aureus colonisation, including two MRSA. S. aureus colonisation was associated with technology-dependent children, while being on antibiotic prophylaxis or having undergone antibiotic therapy in the previous month were protective factors. The prevalence of MR-GNB colonisation was 27%, which was associated with immunosuppressive therapy (aOR 31; 2.02–47]; p = 0.01), antibiotic prophylaxis (aOR 4.56; 1.4–14.86; p = 0.012), previously treated skin-infections (aOR 2.9; 1.07–8.14; p = 0.03), surgery in the previous year (aOR 1.4; 1.06–1.8; p = 0.014), and hospital admission in the previous year (aOR 1.79; [1.26–2.56]; p = 0.001). The rate of S. aureus nasal colonisation in this series was not high despite the presence of chronic conditions, and few cases corresponded to MRSA. Antibiotic prophylaxis, immunosuppressive therapies, history of infections, previous surgeries, and length of admission in the previous year were risk factors for MR-GNB colonisation.

Cost-effectiveness analysis of vaborem for the treatment of carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae carbapenemase (CRE-KPC) infections in the UK

OBJECTIVE

The study objective of this analysis was to determine the cost-effectiveness of vaborem (meropenem-vaborbactam) compared to the best available therapy (BAT) in adult patients with carbapenem-resistant Enterobacteriaceae-Klebsiella pneumoniae carbapenemase (CRE-KPC) infections from the perspective of the UK National Health Service (NHS) and Personal Social Services (PSS).

METHODS

A decision tree model was developed to conduct a cost-effectiveness analysis for Vaborem compared to BAT in CRE-KPC patients over a 5 year time horizon. The model structure for Vaborem simulated the clinical pathway of patients with a confirmed CRE-KPC infection. Model inputs for clinical effectiveness were sourced from the TANGO II trial, and published literature. Costs, resource use and utility values associated with CRE-KPC infections in the UK were sourced from the British National Formulary, NHS reference costs and published sources.

RESULTS

Over a 5 year time horizon, Vaborem use increased total costs by £5165 and increased quality-adjusted life years (QALYs) by 0.366, resulting in an incremental cost-effectiveness ratio (ICER) of £14,113 per QALY gained. The ICER was most sensitive to the probability of discharge to long-term care (LTC), the annual cost of LTC and the utility of discharge to home. At thresholds of £20,000/QALY and £30,000/QALY, the probability of Vaborem being cost-effective compared to BAT was 79.85% and 94.93%, respectively.

CONCLUSION

Due to a limited cost impact and increase in patient quality of life, vaborem can be considered as a cost-effective treatment option compared to BAT for adult patients with CRE-KPC infections in the UK.

A Novel Nomogram for Predicting Risk Factors and Outcomes in Bloodstream Infections Caused by Klebsiella pneumoniae

Background

Our study aimed to explore the risk factors in bloodstream infections Klebsiella pneumoniae (BSI-KP) patients and establish nomograms to predict the probability of BSI-CRKP and the prognosis of BSI-KP.

Methods

A total of 252 BSI-KP patients were enrolled from a tertiary teaching hospital between January 1, 2015, and May 31, 2020. Risk factors associated with BSI-CRKP and factors associated with the 30-day mortality were identified using LASSO analysis, univariate and multivariate analysis.

Results

There were 121 (48.0%) patients with carbapenem-resistant K. pneumoniae (CRKP) and 131 (52.0%) patients with carbapenem-susceptible K. pneumoniae (CSKP). The multivariate logistic regression analysis demonstrated that gastric tube indwelling before BSI (OR=2.442, P=0.043) and more types of antibiotics use before BSI (OR=1.305, P=0.009) were independent risk factors for BSI-CRKP. And previous transplantations, prior ICU stay, gastric tube indwelling before BSI, more types of antibiotics use before BSI, lower Hb and cholinesterase were associated with CRKP-BSI. The C-index of models indicated its good accuracy (C-index 0.816, 95% CI 0.763–0.868). In patients with BSI-CRKP, further logistic regression analysis revealed urinary catheterization (OR=0.298, P=0.017) was found to be an independent risk factor for 30-day mortality, while ceftazidime/avibactam use (OR=8.438, P=0.003) was an independent favorable prognostic factor. The nomogram predicated CRKP, ICU hospitalization, more types of antibiotics use, tigecycline, PLT, urinary catheterization were associated with 30-day mortality in patients with BSI-KP. The discriminative ability of the predictive model, as assessed by C-index, was 0.813 (95% CI: 0.780–0.867).

Conclusion

Previous transplantations, prior ICU stay, gastric tube indwelling before BSI, more types of antibiotics use before BSI, lower Hb and cholinesterase represent significant risk factors for the development of BSI-CRKP. Our nomogram predicated thrombocytopenia was a sign for poor prognosis. Tigecycline resulted in higher mortality for patients with BSI-KP. Rational use of nomograms may help clinicians make better Clinical decisions when treating BSI-KP patients.

Karunakaran R, Abdul Jabar K, Ponnampalavanar S, Chong CW, Teh CSJ. A retrospective study on molecular epidemiology trends of carbapenem resistant Enterobacteriaceae in a teaching hospital in Malaysia

BACKGROUND

Carbapenem resistant Enterobacteriaceae (CRE) has rapidly disseminated worldwide and has become a global threat to the healthcare system due to its resistance towards "last line" antibiotics. This study aimed to investigate the prevalence of CRE and the resistance mechanism as well as the risk factors associated with in-hospital mortality.

METHODS

A total of 168 CRE strains isolated from a tertiary teaching hospital from 2014-2015 were included in this study. The presence of carbapenemase genes and minimum inhibitory concentration of imipenem, meropenem and colistin were investigated. All carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae) strains were characterised by PFGE. The risk factors of patients infected by CRE associated with in-hospital mortality were determined statistically.

RESULTS

The predominant CRE species isolated was K. pneumoniae. The carbapenemases detected were blaOXA-48, blaOXA-232, blaVIM and blaNDM of which blaOXA-48 was the predominant carbapenemase detected among 168 CRE strains. A total of 40 CRE strains harboured two different carbapenemase genes. A total of seven clusters and 48 pulsotypes were identified among 140 CRKp strains. A predominant pulsotype responsible for the transmission from 2014 to 2015 was identified. Univariate statistical analysis identified that the period between CRE isolation and start of appropriate therapy of more than 3 days was statistically associated with in-hospital mortality.

Molecular characterization of carbapenemase producing Klebsiella pneumoniae strains by multiplex PCR and PFGE methods: The first K.pneumoniae isolates co-producing OXA-48/KPC and KPC/NDM in Turkey

INTRODUCTION

Carbapenems are frequently used in the treatment of multidrug-resistant infections caused by Klebsiella pneumoniae. The aim of the study is to definition and incidence of transferable carbapenemase genes of carbapenem resistant K. pneumoniae (CRKP) and to determine clonal relatedness of these strains in tertiary care hospital in Turkey.

METHODS

Identification of all 100 K. pneumoniae isolates and low sensitivity to any of the carbapenem group antibiotics were determined by Vitek-2 (BioMérieux, France). The frequency of carbapenemase genes (bla_OXA-48, bla_NDM, bla_KPC, bla_VIM,bla_IMP) and extended spectrum beta-lactamase (ESBL) genes (bla_CTX-M, bla_SHV, bla_TEM) which frequently detected in Turkey, have been investigated by multiplex polymerase chain reaction (PCR). Clonal relatedness was determined using Pulsed-field gel electrophoresis(PFGE).

RESULTS

Ninety five isolates carried at least one of the carbapenemase genes (81.05% bla_OXA-48, 38.9% bla_NDM, 9.47% bla_KPC,1.05% bla_VIM). One isolate was carried the bla_OXA-48+KPC and the two isolates were carried the bla_KPC+NDM. PFGE demonstrated the presence of 24 pulse types and 63.09% of the isolates were in four main pulse types.

CONCLUSIONS

This study demonstrated the incidence of bla_NDM is beginning to reach endemic levels, in addition to bla_OXA-48 found endemic in Turkey. To our knowledge, this is the first report of the co-production of these two genes (bla_{KPC + NDM} and bla_{OXA-48 + KPC}) in CRKP isolates.

New insights and antimicrobial stewardship opportunities in viral pneumonia: five lung ultrasound cases

Background

Antimicrobial stewardship is crucial to avoid antimicrobial resistance in microbes and adverse drug effects in patients. In respiratory infections, however, viral pneumonia is difficult to distinguish from bacterial pneumonia, which explains the overuse of antibiotic therapy in this indication.

Cases

Five cases of lung consolidation are presented. Lung ultrasound, in conjunction with procalcitonin levels, were used to exclude or corroborate bacterial pneumonia.

Conclusion

Lung ultrasound is easy to learn and perform and is helpful in guiding diagnosis in unclear cases of pneumonia and may also offer new insights into the spectrum of certain virus diseases. The use of lung ultrasound can raise awareness in clinicians of the need for antimicrobial stewardship and may help to avoid the unnecessary use of antibiotics.

Supplementary Information

The online version of this article (10.1007/s00508-021-01946-4) contains supplementary material, which is available to authorized users.

Risk Factors for the Acquisition of a blaNDM-5 Carbapenem-Resistant Escherichia coli in a Veterinary Hospital

Carbapenem-resistant Enterobacteriaceae (CRE) are an urgent antibiotic resistant threat. Only sporadic reports of CRE in companion animals have been described. Our objective was to identify risk factors associated with the acquisition of a blaNDM-5 CR-Escherichia coli strain as part of an outbreak investigation at a tertiary veterinary hospital in the United States. A matched case-control study was conducted among companion animals admitted during July 1, 2018, through June 30, 2019. The 15 identified blaNDM-5 CR-E coli cases were matched 1:2 with controls (culture negative for blaNDM-5 CR-E coli) based on species and number of days of hospitalization before bacterial culture sample collection. The association between exposure to various procedures and hospital services and the acquisition of blaNDM-5 CR-E. coli was assessed through conditional logistic regression. Case patients had significantly higher odds of exposure to the anesthesia service (odds ratio [OR] = 12.8, P = .017), the surgical service (OR = 4.0, P = .046), and to endotracheal intubation (OR = 10.0, P = .03). Veterinary hospitals should be aware of the potential for transmission of CRE via anesthetic and surgical procedures, especially those that require the placement of endotracheal tubes.

Biocompatibility, cytotoxicity and antibacterial effects of meropenem-loaded mesoporous silica nanoparticles against carbapenem-resistant Enterobacteriaceae

BACKGROUND

The ever-increasing resistance to antimicrobial agents among bacteria associated with nosocomial infections indicate the necessity of new antimicrobial therapy. The nanoparticles are considered as new drug delivery systems to increase the efficiency and decrease the unfavourable effects of the antimicrobial agents.

METHODS

Herein we report the preparation and characterization of mesoporous silica nanoparticles (MSNs) loaded with meropenem against carbapenem-resistant Enterobacteriaceae. The antimicrobial effect of meropenem-loaded MSNs was determined against Enterobacteriaceae using the minimum inhibitory (MIC) method. The biocompatibility of meropenem-loaded MSNs was studied by the impact on the haemolysis and sedimentation rates of human red blood cells (HRBCs). Cytotoxicity of the meropenem-loaded MSNs was studied by the MTT test (hBM-MSC cell viability).

RESULTS

The meropenem-loaded MSNs have shown antibacterial activity on all isolates at different MIC values lower than MICs of meropenem. Free MSNs did not show any significant antibacterial effect. Meropenem-loaded MSNs have no significant effect on haemolysis and ESR of HRBCs. The viability of hBM-MSC cells treated with serial concentrations of meropenem-loaded MSNs was 92-100%.

CONCLUSION

Due to the desirable biocompatibility, low cytotoxicity and the improved antibacterial effect, MSNs can be considered as a promising drug delivery system for meropenem as a potential antimicrobial agent.

Comparison of colistin-induced nephrotoxicity between two different formulations of colistin in critically ill patients: a retrospective cohort study

Background

Colistin is widely used in the treatment of nosocomial infections caused by carbapenem-resistant gram-negative bacilli (CR-GNB). Colistin-induced nephrotoxicity is one of the major adverse reactions during colistin treatment. Comparisons of colistin-induced nephrotoxicity between different formulations of colistin are rarely reported.

Methods

In this retrospective cohort study, we enrolled intensive care unit–admitted patients if they had culture isolates of CR-GNB and underwent intravenous treatment with colistin. The occurrence of acute kidney injury (AKI) during intravenous treatment with colistin was recorded. The occurrence of colistin-induced nephrotoxicity was compared between two formulations of colistin, Locolin®, and Colimycin®. Treatment outcomes associated with the occurrence of colistin-induced nephrotoxicity were also investigated.

Results

Among 195 patients, 95 who were treated with Locolin® and 100 who were treated with Colimycin® were included for analysis. Patients treated with Locolin® had a higher rate of occurrence of stage 2 (46.3% vs. 32%, p = 0.040) and stage 3 (29.5% vs. 13%, p = 0.005) AKI than did those treated with Colimycin®. In multivariate analysis, the presence of septic shock (adjusted odds ratio [aOR] 2.17, 95% confidence interval [CI] 1.10–4.26) and inappropriate colistin dosage (aOR 2.52, 95% CI 1.00–6.33) were clinical factors associated with colistin-induced nephrotoxicity. Treatment with Colimycin® was an independent factor associated with a lower risk of colistin-induced nephrotoxicity (aOR 0.37, 95% CI 0.18–0.77). The mortality rate was comparable between patients with and without colistin-induced nephrotoxicity.

Conclusions

The risk of colistin-induced nephrotoxicity significantly varied in different formulations of colistin in critically ill patients. Colistin-induced nephrotoxicity was not associated with increased mortality rate.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-021-00977-w.

Epidemiology and Transmission of Carbapenemase-Producing Enterobacteriaceae in a Health Care Network of an Acute-Care Hospital and Its Affiliated Intermediate- and Long-Term-Care Facilities in Singapore

Movement of patients in a health care network poses challenges for the control of carbapenemase-producing Enterobacteriaceae (CPE). We aimed to identify intra- and interfacility transmission events and facility type-specific risk factors of CPE in an acute-care hospital (ACH) and its intermediate-term and long-term-care facilities (ILTCFs). Serial cross-sectional studies were conducted in June and July of 2014 to 2016 to screen for CPE. Whole-genome sequencing was done to identify strain relatedness and CPE genes (bla_IMI, bla_IMP-1, bla_KPC-2, bla_NDM-1, and bla_OXA-48). Multivariable logistic regression models, stratified by facility type, were used to determine independent risk factors. Of 5,357 patients, half (55%) were from the ACH. CPE prevalence was 1.3% in the ACH and 0.7% in ILTCFs (P = 0.029). After adjusting for sociodemographics, screening year, and facility type, the odds of CPE colonization increased significantly with a hospital stay of ≥3 weeks (adjusted odds ratio [aOR], 2.67; 95% confidence interval [CI], 1.17 to 6.05), penicillin use (aOR, 3.00; 95% CI, 1.05 to 8.56), proton pump inhibitor use (aOR, 3.20; 95% CI, 1.05 to 9.80), dementia (aOR, 3.42; 95% CI, 1.38 to 8.49), connective tissue disease (aOR, 5.10; 95% CI, 1.19 to 21.81), and prior carbapenem-resistant Enterobacteriaceae (CRE) carriage (aOR, 109.02; 95% CI, 28.47 to 417.44) in the ACH. For ILTCFs, presence of wounds (aOR, 5.30; 95% CI, 1.01 to 27.72), respiratory procedures (aOR, 4.97; 95% CI, 1.09 to 22.71), vancomycin-resistant enterococcus carriage (aOR, 16.42; 95% CI, 1.52 to 177.48), and CRE carriage (aOR, 758.30; 95% CI, 33.86 to 16,982.52) showed significant association. Genomic analysis revealed only possible intra-ACH transmission and no evidence for ACH-to-ILTCF transmission. Although CPE colonization was predominantly in the ACH, risk factors varied between facilities. Targeted screening and precautionary measures are warranted.

Clinical and epidemiological features of patients colonised by different types of carbapenemase-producing Enterobacterales

OBJECTIVES

The aim of this study was to compare the epidemiological and clinical characteristics of hospitalised patients colonised or infected by different types of carbapenemase-producing Enterobacterales (CPE) and to analyse the differences in their outcome.

METHODS

This was a retrospective comparative study of all patients colonised or infected by KPC-, NDM- or OXA-48-producing CPE who were hospitalised between 1 January 2018 and 30 June 2019. Microbiological, demographic and clinical data were collected from the patients' computerised files.

RESULTS

One type of CPE was isolated in 285 patients, including 138 with KPC-CPE, 94 with NDM-CPE and 53 with OXA-48-CPE. The most common CPE types were KPC-Klebsiella pneumoniae (n = 47), OXA-48-Escherichia coli (n = 38), NDM-Enterobacter cloacae complex (n = 35) and KPC-Citrobacter freundii (n = 37). All three groups of patients were similar with respect to their risk factors, with the exception of previous exposure to antimicrobials that was more common in patients with KPC-CPE compared with OXA-48-CPE. Also, these patients were more likely to be co-infected by other multidrug-resistant bacteria. Clinical infections were more common in KPC-CPE than in OXA-48-CPE carriers (9.9% vs. 1.9%; P = 0.033). No other demographic or clinical variables were found to be correlated with clinical infections.

CONCLUSION

Our study suggests that colonisation by OXA-48-CPE might be less risky compared with KPC-CPE.

Molecular epidemiology of carbapenem-resistant Enterobacterales in Thailand, 2016-2018

Background

Carbapenem-resistant Enterobacterales (CRE) is a global threat. Enterobacterales develops carbapenem resistance through several mechanisms, including the production of carbapenemases. We aim to describe the prevalence of Carbapenem-resistant Enterobacterales (CRE) with and without carbapenemase production and distribution of carbapenemase-producing (CP) genes in Thailand using 2016–2018 data from a national antimicrobial resistance surveillance system developed by the Thailand National Institute of Health (NIH).

Methods

CRE was defined as any Enterobacterales resistant to ertapenem, imipenem, or meropenem. Starting in 2016, 25 tertiary care hospitals from the five regions of Thailand submitted the first CRE isolate from each specimen type and patient admission to Thailand NIH, accompanied by a case report form with patient information. NIH performed confirmatory identification and antimicrobial susceptibility testing and performed multiplex polymerase chain reaction testing to detect CP-genes. Using 2016–2018 data, we calculated proportions of CP-CRE, stratified by specimen type, organism, and CP-gene using SAS 9.4.

Results

Overall, 4,296 presumed CRE isolates were submitted to Thailand NIH; 3,946 (93%) were confirmed CRE. Urine (n = 1622, 41%) and sputum (n = 1380, 35%) were the most common specimen types, while blood only accounted for 323 (8%) CRE isolates. The most common organism was Klebsiella pneumoniae (n = 2660, 72%), followed by Escherichia coli (n = 799, 22%). The proportion of CP-CRE was high for all organism types (range: 85–98%). Of all CRE isolates, 2909 (80%) had one CP-gene and 629 (17%) had > 1 CP-gene. New Delhi metallo-beta-lactamase (NDM) was the most common CP-gene, present in 2392 (65%) CRE isolates. K. pneumoniae carbapenemase (KPC) and Verona integron-encoded metallo-β-lactamase (VIM) genes were not detected among any isolates.

Conclusion

CP genes were found in a high proportion (97%) of CRE isolates from hospitals across Thailand. The prevalence of NDM and OXA-48-like genes in Thailand is consistent with pattern seen in Southeast Asia, but different from that in the United States and other regions. As carbapenemase testing is not routinely performed in Thailand, hospital staff should consider treating all patients with CRE with enhanced infection control measures; in line with CDC recommendation for enhanced infection control measures for CP-CRE because of their high propensity to spread.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-021-00950-7.

Risk Factors for and Clinical Outcomes of Carbapenem-Resistant Klebsiella pneumoniae Nosocomial Infections: A Retrospective Study in a Tertiary Hospital in Beijing, China

Purpose

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections have been increasingly reported worldwide. We aimed to identify the risk factors for nosocomial CRKP infections and assess the clinical outcomes.

Patients and Methods

We conducted a case-control study with data collected from January 2016 to December 2018 in China. Controls were selected at a ratio of 1:1 from patients with nosocomial carbapenem-susceptible Klebsiella pneumonia (CSKP) infections. Risk factors for nosocomial CRKP infections and clinical outcomes were assessed with univariate and multivariate analyses.

Results

A total of one hundred forty-two patients with CRKP infections and one hundred forty-two patients with CSKP infections were enrolled in this study. Multivariate analysis showed that exposure to antibiotics within 3 months prior to admission (odds ratio OR, 2.585; 95% confidence interval [CI], 1.425–4.691; P=0.002), exposure to carbapenems (OR, 2.532; 95% CI, 1.376–4.660; P=0.003), exposure to fluoroquinolones (OR, 3.309; 95% CI, 1.326–8.257; P=0.010), and the presence of a nasogastric tube (OR, 2.796; 95% CI, 1.369–5.712; P=0.005) were independent risk factors for CRKP infections. The 30-day mortality rate in the CRKP group was 19.7%, while the in-hospital mortality rate was 28.9%. In the CRKP group, a higher creatinine level (OR, 1.009; 95% CI, 1.002–1.016; P = 0.013), being in shock at the time of a positive culture (OR, 4.454; 95% CI, 1.374–14.443; P = 0.013), and co-infection with other resistant bacteria (OR, 4.799; 95% CI, 1.229–18.740; P = 0.024) were independent predictors of in-hospital mortality in patients with CRKP infections. Kaplan–Meier curves showed that the CRKP group had a shorter survival time than the CSKP group.

Conclusion

Nosocomial CRKP infection was associated with exposure to carbapenems and fluoroquinolones within 3 months prior to hospitalization and the presence of a nasogastric tube. Patients infected with CRKP had higher 30-day and in-hospital mortality rates. A higher creatinine level, shock and co-infection with other resistant bacteria were independent predictors of in-hospital mortality in patients with CRKP infections.

A multispecies outbreak of carbapenem-resistant bacteria harboring the blaKPC gene in a non-classical transposon element

Background

Klebsiella pneumoniae is the most frequent KPC-producing bacteria. The bla_KPC gene is frequently embedded in Tn4401 transposon, and less frequently in non-Tn4401 elements (NTE_KPC) variants I-III. The first case of KPC in the UC-CHRISTUS Clinical Hospital was detected in Pseudomonas aeruginosa. Soon after this event, KPC was detected in 2 additional Pseudomonas aeruginosa, 3 Escherichia coli, 3 Enterobacter cloacae, 3 Klebsiella pneumoniae, and 1 Citrobacter freundii, isolated from 6 different patients. We aimed to elucidate the possible mechanisms of genetic transfer and dissemination of the bla_KPC gene among isolates of this multispecies outbreak. A molecular epidemiology analysis of the above mentioned clinical isolates (n = 13) through Multi-Locus Sequence Typing, plasmid analysis, Pulsed-Field Gel-Electrophoresis, and Whole-genome sequencing (WGS) was performed.

Results

High-risk sequence types were found: K. pneumoniae ST11, P. aeruginosa ST654, and E. cloacae ST114. All enterobacterial isolates were not clonal except for 3 E. coli isolated from the same patient. WGS analysis in 6 enterobacterial isolates showed that 4 of them had bla_KPC embedded in a novel variant of NTE_KPC designated NTE_KPC-IIe. Upstream of bla_KPC gene there was a 570 pb truncated bla_TEM-1 gene followed by an insertion sequence that was 84% similar to ISEc63, a 4473 bp element of the Tn3 family. Downstream the bla_KPC gene there was a truncated ISKpn6 gene, and the inverted repeat right sequence of Tn4401. The ISec63-like element together with the bla_KPC gene plus Tn4401 remnants were inserted in the Tra operon involved in conjugative transfer of the plasmid. This NTE was carried in a broad host-range IncN plasmid. P. aeruginosa isolates carried bla_KPC gene embedded in a typical Tn4401b transposon in a different plasmid, suggesting that there was no plasmid transfer between Enterobacteriaceae and P. aeruginosa as initially hypothesized.

Conclusions

Most enterobacterial isolates had bla_KPC embedded in the same NTE_KPC-IIe element, suggesting that this multispecies KPC outbreak was due to horizontal gene transfer rather than clonal spread. This poses a greater challenge to infection control measures often directed against containment of clonal spread.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02169-3.

Carbapenem-Resistant Enterobacteriaceae-Implications for Treating Acute Leukemias, a Subgroup of Hematological Malignancies

Acute leukemias (AL) are a group of aggressive malignant diseases associated with a high degree of morbidity and mortality. Patients with AL are highly susceptible to infectious diseases due to the disease itself, factors attributed to treatment, and specific individual risk factors. Enterobacteriaceae presence (e.g., Klebsiella pneumonia and Escherichia coli) is a frequent cause of bloodstream infections in AL patients. Carbapenem-resistant Enterobacteriaceae (CRE) is an emerging health problem worldwide; however, the incidence of CRE varies greatly between different regions. Carbapenem resistance in Enterobacteriaceae is caused by different mechanisms, and CRE may display various resistance profiles. Bacterial co-expression of genes conferring resistance to both broad-spectrum β-lactam antibiotics (including carbapenems) and other classes of antibiotics may give rise to multidrug-resistant organisms (MDROs). The spread of CRE represents a major treatment challenge for clinicians due to lack of randomized clinical trials (RCTs), a limited number of antibiotics available, and the side-effects associated with them. Most research concerning CRE infections in AL patients are limited to case reports and retrospective reviews. Current research recommends treatment with older antibiotics, such as polymyxins, fosfomycin, older aminoglycosides, and in some cases carbapenems. To prevent the spread of resistant microbes, it is of pivotal interest to implement antibiotic stewardship to reduce broad-spectrum antibiotic treatment, but without giving too narrow a treatment to neutropenic infected patients.

Longitudinal Study of the Drug Resistance in Klebsiella pneumoniae of a Tertiary Hospital, China: Phenotypic Epidemiology Analysis (2013-2018)

Purpose

Multi-drug resistant Klebsiella pneumoniae (MDR KP) is spreading worldwide and has posed a huge medical burden to public health. However, studies on drug resistance surveillance of KP, especially MDR KP, with a large longitudinal sample size in a tertiary hospital are rare. This study aims to investigate phenotypic epidemiology characteristics of 4128 KP isolates in a Chinese tertiary hospital covering a period of 5 years.

Methods

All the KP clinical isolates were retrospectively collected from a tertiary hospital in Hunan province of China from Jan 5, 2013 to Jul 24, 2018. All the isolates were identified by MALDI-TOF MS analysis. Twenty-four antimicrobial agents were tested by antimicrobial susceptibility testing. Fisher exact test and logistic regression were used to analyze the association between clinical factors and antimicrobial non-susceptibility for seven second-choice antimicrobials.

Results

A total of 4128 KP isolates were collected in our study. The non-susceptible rates (NSRs) to ertapenem, imipenem and tigecycline increased considerably from 2013 to 2018 (13.6% to 28.6%, 10.1% to 28.9%, 10.8% to 46.5%, respectively). Amikacin presents the lowest NSR among 3 aminoglycosides (3.8–22.8%). The multi-drug NSRs among KP isolates to second-choice antimicrobials (88.6–100%) were higher than to all drugs (68.0%). The NSRs varied significantly among departments and sample sources. Higher ETP/IPM/AK NSRs (39.8/39.7/30.6%) were observed in Intensive Care Unit, and ETP/IPM non-susceptible isolates tended to distribute in cerebrospinal fluid. From 2015 to 2017, the NSRs of ETP, IPM, and AK showed an opposite trend of seasonal fluctuations to SXT.

Conclusion

Higher multi-drug resistance (MDR) rates were observed in KP isolates to second-choice antimicrobials than to others, among which MDR rates to carbapenems or AK are the highest. A unique pattern of MIC and time distributions of MDR were observed. Clinical factors including gender were correlated with MDR rates of KP. Isolates in ICU and CSF showed higher NSRs in carbapenems which should be paid more attention to, and temporal distribution of NSRs was observed.

Detection of IncN-pST15 one-health plasmid harbouring blaKPC-2 in a hypermucoviscous Klebsiella pneumoniae CG258 isolated from an infected dog, Brazil

The emergence and rapid spread of carbapenemase‐producing Enterobacterales represents a serious public health concern. Critically, these global priority bacteria have begun to be reported in companion animals, implying a potential risk of cross‐transmission between humans and pets. Using long‐read (MinION) and short‐read (Illumina) sequencing technologies, we have identified and characterized a hypermucoviscous KPC‐2‐producing Klebsiella pneumoniae strain belonging to the high‐risk international clone ST11/CG258, in a dog with urinary tract infection. Strikingly, the bla_KPC‐2 gene was carried by a 54‐kb IncN plasmid assignated to ST15, which shared 99.8 and 96.8% pairwise identity with IncN‐pST15 plasmids from human and environmental K. pneumoniae strains, respectively; all come from an area with high endemicity of KPC‐2. Our findings suggest that IncN‐pST15 plasmids conferring carbapenem resistance can play as important a role as clonal transmission of K. pneumoniae, representing another major challenge for One Health.

A mathematical model and inference method for bacterial colonization in hospital units applied to active surveillance data for carbapenem-resistant enterobacteriaceae

Widespread use of antibiotics has resulted in an increase in antimicrobial-resistant microorganisms. Although not all bacterial contact results in infection, patients can become asymptomatically colonized, increasing the risk of infection and pathogen transmission. Consequently, many institutions have begun active surveillance, but in non-research settings, the resulting data are often incomplete and may include non-random testing, making conventional epidemiological analysis problematic. We describe a mathematical model and inference method for in-hospital bacterial colonization and transmission of carbapenem-resistant Enterobacteriaceae that is tailored for analysis of active surveillance data with incomplete observations. The model and inference method make use of the full detailed state of the hospital unit, which takes into account the colonization status of each individual in the unit and not only the number of colonized patients at any given time. The inference method computes the exact likelihood of all possible histories consistent with partial observations (despite the exponential increase in possible states that can make likelihood calculation intractable for large hospital units), includes techniques to improve computational efficiency, is tested by computer simulation, and is applied to active surveillance data from a 13-bed rehabilitation unit in New York City. The inference method for exact likelihood calculation is applicable to other Markov models incorporating incomplete observations. The parameters that we identify are the patient-patient transmission rate, pre-existing colonization probability, and prior-to-new-patient transmission probability. Besides identifying the parameters, we predict the effects on the total prevalence (0.07 of the total colonized patient-days) of changing the parameters and estimate the increase in total prevalence attributable to patient-patient transmission (0.02) above the baseline pre-existing colonization (0.05). Simulations with a colonized versus uncolonized long-stay patient had 44% higher total prevalence, suggesting that the long-stay patient may have been a reservoir of transmission. High-priority interventions may include isolation of incoming colonized patients and repeated screening of long-stay patients.

Emergence of a Clinical Escherichia coli Sequence Type 131 Strain Carrying a Chromosomal bla KPC-2 Gene

Objectives: Bacteria carrying the Klebsiella pneumoniae carbapenemase genes have rapidly spread worldwide and have become a great threat to public health. The bla_KPC–2 gene has been primarily located on plasmids cocirculating in various strains. However, chromosomal integration of the bla_KPC–2 gene in Escherichia coli has not been reported. In the present study, we report the detection of the first clinical strain of E. coli ST131 with a bla_KPC–2 gene, which integrated in the chromosome. E. coli strain EC3385 was identified and subjected to susceptibility testing and genotyping. The complete genome sequences of this strain and four Proteus mirabilis strains were obtained. Chromosomal integration of the bla_KPC–2 gene was confirmed using a combination of short- and long-read sequencing. Comparative genetic analyses were performed and the origin of the chromosomal location of the bla_KPC–2 gene was further analyzed. Whole-genome sequencing revealed that strain EC3385 belonged to the ST131 type and possessed various resistance and virulence genes. Sequence analysis showed that the bla_KPC–2 gene was carried in a 24-kb insertion sequence on the chromosome. This insertion sequence possessed high sequence similarity to previously reported bla_KPC–2-habouring plasmids of P. mirabilis in China. To the best of our knowledge, this is the first report of a clinical ST131 E. coli strain carrying bla_KPC–2 on the chromosome. The bla_KPC–2 gene was probably horizontally transferred from the P. mirabilis plasmid to the E. coli chromosome by the IS26 element, indicating that P. mirabilis might be an important reservoir of bla_KPC–2 gene for E. coli. Furthermore, the E. coli ST131 strain carrying the chromosomal bla_KPC–2 gene could be further spread due to its carbapenem resistance and high virulence. It is imperative to perform active surveillance to prevent further dissemination of KPC-2 type carbapenemase-producing isolates.

Combination of modified carbapenem inactivation method (mCIM) and EDTA-CIM (eCIM) for phenotypic detection of carbapenemase-producing Enterobacteriaceae

Background

Carbapenemase-resistant Enterobacteriaceae (CRE) cause many serious infections resulting in increasing treatment cost, prolonged hospitalization, and mortality rate. Reduced expression and/or mutations of porins and the presence of carbapenemase promote Enterobacteriaceae survival under carbapenem treatments. Development of accurate methods for the detection of antimicrobial resistance is required not only for therapy but also to monitor the spread of resistant bacteria or resistance genes throughout the hospital and community. In this study, we aimed to evaluate the phenotypic methods, Modified Hodge test (MHT), modified carbapenem inactivation method (mCIM), and EDTA-CIM (eCIM) for the detection of carbapenemase-producing Enterobacteriaceae (CPE).

Results

The results showed that mCIM had a sensitivity of 100% and a specificity of 100%, whereas the MHT had a sensitivity of 84.8% and a specificity of 97.8% for the 195 CRE isolates tested (105 CPE and 90 non-CPE isolates). The sensitivity of the mCIM/eCIM to detect metallo-carbapenemases in this study was 89.3% and the specificity was 98.7% as compared to the genotypic PCR detection.

Conclusions

These findings indicate that the mCIM combined with eCIM is useful for detecting and distinguishing different types of carbapenemase in Enterobacteriaceae.

Carbapenem-resistant Enterobacteriaceae (CRE) and gram-negative bacterial infections in south-west Nigeria: a retrospective epidemiological surveillance study

Background

Carbapenem-resistant Enterobacteriaceae (CRE) are often responsible for severe, life-threatening infections and they represent a critical threat to the available antibiotic agents and to global health. An understanding of the epidemiology of these infections will be indispensable to the development of appropriate case management as well as infection prevention and control (IPC) measures in any healthcare setting.

Objectives

The objective of this study was to investigate and describe the epidemiology of carbapenem-resistant Enterobacteriaceae (CRE) and other gram-negative bacteria in a tertiary hospital in south west Nigeria using routinely collected microbiological laboratory data.

Methods

A retrospective collection of microbiological laboratory records from the January to June 2018 was performed. All culture and antimicrobial susceptibility test results of patients who required laboratory tests were collected. Other information collected include: patient demographics, clinical specimen types and the requesting hospital department. The data was analyzed using SPSS Windows version 24. Comparison between categorical variables was done using chi-square tests while independent sample t-test was used to determine significant mean differences between groups. A p < 0.05 was taken to be statistically significant.

Results

The prevalence of carbapenem-resistance among Enterobacteriaceae and gram-negative bacteria isolates was 22% (n = 39/177). Of these, 35.9% (n = 14) were Klebsiella pneumonia, 30.8% (n = 12) were Pseudomonas aeruginosa and 15.4% (n = 6) were Klebsiella oxytoca. 87.2% (n = 34) of these were also multi-drug resistant, with a mean total resistance score of 3.92 (SD = ± 1.44). There were differences observed in proportion of carbapenem-resistance across clinical specialties and age groups; however, these differences were not statistically significant. Independent sample t-test revealed that carbapenem-resistant isolates exhibited more drug resistance than carbapenem-sensitive isolates (3.93 vs. 2.30; p < 0.001).

Conclusion

Carbapenem resistance is an important threat to the current antibiotic armory. Active surveillance, particularly in the healthcare setting is required to identify high risk groups, inform better treatment options and infection prevention and control measures.

Incidence and risk factors of carbapenem-resistant Enterobacteriaceae infection in intensive care units: a matched case-control study

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) infection is associated with intensive care admissions, morbidity, and mortality. Our study aimed to determine the incidence, risk factors, and patient outcomes of CRE in the ICU units.

METHODS

This was a retrospective matched case-control study of patients admitted to ICUs. Patients who have positive cultures of CRE and carbapenem-susceptible Enterobacteriaceae (CSE) were included in the study. Patients were randomly selected from a pool of CSE subjects in a ratio of 1:1 of CRE to CSE as control patients.

RESULTS

The infection rate with CRE among all patients admitted to ICUs was 7.6% and the incidence of CRE infection was 5.6 per 1,000 person-day. The risk factors independently associated with CRE infection were: Higher Sequential Organ Failure Assessment (SOFA) and Nutrition Risk in Critically ill (NUTRIC) scores, prolonged ICU length of stay (LOS), previous surgery, dialysis and mechanical ventilation during ICU stay, and previous use of aminoglycoside and carbapenems.

CONCLUSION

In this retrospective study, the incidence of CRE infection was relatively elevated in patients admitted to ICU. Patients with high SOFA and NUTRIC scores, prolonged ICU LOS, previous surgery, dialysis and mechanical ventilation, and prior aminoglycosides and carbapenems use, may have an increased risk of CRE infection.

The Effect of Host Immunity on Predicting the Mortality of Carbapenem-Resistant Organism Infection

Carbapenem-resistant organisms (CROs) are associated with considerable mortality clinically. There is a lack of effective tool to predict individual prognosis. We aim to determine if host immunity can be utilized to predict the prognosis of patients infected with CRO. From December 2018 to August 2019, we recruited CRO-infected patients to evaluate risk factors for 30-day mortality. Clinical, routine laboratory, immune and microbiological features were investigated and subjected to univariate and multivariate analyses. The final predictive models were established based on the regression coefficients of multivariate logistic regression. A total of 127 CRO-infected patients were enrolled in our study, including 85 survivors and 42 non-survivors. The number and IFN-γ producing ability of lymphocytes were remarkably decreased in non-survivors. The number of IFN-γ⁺CD4⁺ T cells could effectively predict 30-day mortality of CRO infection. Its area under the receiver operating characteristic (ROC) curve, sensitivity, specificity and accuracy, were 0.889 (95% confidence interval [CI], 0.834-0.945), 81.0, 80.0, and 80.3%, respectively. In multivariate analysis of laboratory parameters, IFN-γ⁺CD4⁺ T cell number and creatinine concentration were selected for the 2-marker model to predict prognosis fleetly. Its area under the ROC curve, sensitivity, specificity and accuracy were 0.894 (95% CI, 0.841-0.947), 83.3, 82.4, and 82.7%, respectively. Impaired lymphocyte function was an important factor to affect the outcome of CRO-infected patients. A 2-marker model based on the combination of IFN-γ⁺CD4⁺ T cell number and creatinine showed good performance in predicting the prognosis of CRO infection.

Predictive factors for sepsis by carbapenem resistant Gram-negative bacilli in adult critical patients in Rio de Janeiro: a case-case-control design in a prospective cohort study

Background

Studies have investigated risk factors for infections by specific species of carbapenem-resistant Gram-negative bacilli (CR-GNB), but few considered the group of GNB species and most of them were performed in the setting of bacteremia or hospital infection. This study was implemented to identify risk factors for sepsis by CR- and carbapenem-susceptible (CS) GNB in intensive care unit (ICU) patients to improve management strategies for CR-GNB sepsis.

Methods

We developed a case-case-control study from a prospective cohort of patients with systemic inflammatory response syndrome (SIRS), sepsis-2 or sepsis-3 criteria in which blood and other sample cultures were collected and antimicrobial therapy was instituted, in an adult clinical-surgical ICU, at tertiary public hospital in Rio de Janeiro, from August 2015 through March 2017.

Results

Among the total of 629 ICU admissions followed by 7797 patient-days, after applying inclusion and exclusion criteria we identified 184 patients who developed recurrent or single hospital-acquired sepsis. More than 90% of all evaluable cases of sepsis and 87% of control group fulfilled the modified sepsis-3 definition. Non-fermenting bacilli and ventilator-associated pneumonia predominated as etiology and source of CR-GNB sepsis. While Enterobacteriaceae and intra-abdominal surgical site plus urinary-tract infections prevailed in CS-GNB than CR-GNB sepsis. Carbapenemase production was estimated in 76% of CR-GNB isolates. Multivariate logistic regression analysis revealed previous infection (mostly hospital-acquired bacterial infection or sepsis) (OR = 4.28; 95% CI 1.77–10.35), mechanical ventilation (OR = 4.21; 95% CI 1.17–15.18), carbapenem use (OR = 3.42; 95% CI 1.37–8.52) and length of hospital stay (OR = 1.03; 95% CI 1.01–1.05) as independent risk factors for sepsis by CR-GNB. While ICU readmission (OR = 6.92; 95% CI 1.72–27.78) and nosocomial diarrhea (OR = 5.32; 95% CI 1.07–26.45) were factors associated with CS-GNB sepsis.

Conclusions

The investigation of recurrent and not only bacteremic episodes of sepsis was the differential of this study. The results are in agreement with the basic information in the literature. This may help improve management strategies and future studies on sepsis by CR-GNB.

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.

Molecular Characteristics of Carbapenem-Resistant Enterobacter cloacae in a Tertiary Hospital in China

Background

Infections caused by the carbapenem-resistant Enterobacter cloacae (CREC) bring great challenges to the clinical treatment and pose a serious threat to public health. In this study, we investigated the molecular characteristics of CREC in a tertiary hospital.

Materials and Methods

A total of 12 non-duplicate CREC strains isolated during the period of November 2016 to July 2019 were subjected to automated microbial identification and antimicrobial susceptibility testing (AST) using the BD Phoenix-100 identification and antimicrobial susceptibility testing (ID/AST) system. The strains were also subjected to phenotypic screening for the detection of antibiotic resistance genes such as the carbapenemase and other β-lactamase genes, with the use of the polymerase chain reaction assay (PCR). Finally, multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE)-based homology analysis were applied.

Results

Four types of carbapenemases namely IMP-26, NDM-5, NDM-1, and KPC-2 were identified in 12 CREC strains. IMP-26 was the most prevalent type (6/12 strains, 50 %), followed by NDM-5 (3/12 strains, 25 %). The results of MLST revealed that these 12 strains could be divided into five sequence types (STs) among which ST544 was the dominant type (6/12 strains, 50 %). The PFGE results divided the 12 strains into four clusters.

Conclusion

Our study indicated that the epidemics of the IMP-26-producing E. cloacae ST544 strain did occur in the intensive care unit (ICU) of a tertiary hospital. Therefore, early surveillance and strict implementation of control measures are crucial for the prevention of nosocomial infections and transmissions in hospitals.