The Epidemiology of Carbapenem-Resistant Klebsiella pneumoniae Colonization and Infection among Long-Term Acute Care Hospital Residents

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.

Efficacy of the bee-venom antimicrobial peptide Osmin against sensitive and carbapenem-resistant Klebsiella pneumoniae strains

The emergence of multidrug-resistant (MDR) Klebsiella pneumoniae strains causes severe problems in the treatment of bacterial infections owing to limited treatment options. Especially, carbapenem-resistant Klebsiella pneumoniae (CRKP) is rapidly spreading worldwide and is emerging as a new cause of drug-resistant healthcare-associated infections. CRKP also has been announced by the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) as one of the most pressing antibiotic resistance threats. Antimicrobial peptides (AMPs) are drawing considerable attention as ideal antibiotic alternative candidates to combat MDR bacterial infections. In a previous study, Osmin is composed of 17 amino acids and is isolated from solitary bee (Osmia rufa) venom. Herein, we evaluated the potential of Osmin to be used against drug-resistant K. pneumoniae as an alternative to conventional antibiotics. Osmin exhibited significant antimicrobial and anti-biofilm activity and lower toxicity than melittin, a well-known bee venom peptide. Additionally, we confirmed that it possesses a bactericidal mechanism that rapidly destroys bacterial membranes. Osmin was relatively more stable than melittin under the influence of various environmental factors and unlike conventional antibiotics, it exhibited a low bacterial resistance risk. During in vivo tests, Osmin reduced bacterial growth and the expression of pro-inflammatory cytokines and fibrosis-related genes in mice with CRKP-induced sepsis. Overall, our results indicate a high potential for Osmin to be used as a valuable therapeutic agent against drug-resistant K. pneumoniae infections.

Prevalence of carbapenemase producing Enterobacterales colonization and risk factor of clinical infection

BACKGROUND

Carbapenemase-producing Enterobacterales (CPE) are global concerns in infection control, and the number of CPE outbreaks in hospitals is increasing despite the strengthening of contact precautions. This study aimed to confirm the prevalence and transition rate of CPE infection from stool surveillance culture and to identify the acquisition pathway of CPE.

METHODS

This is a longitudinal review of patients with stool surveillance cultures at a tertiary center in Seoul, South Korea, from July 2018 to June 2020. Pulsed-field gel electrophoresis, multi-locus sequence typing, and whole genome sequencing were performed for carbapenemase-producing Klebsiella pneumoniae and Escherichia coli strains.

RESULTS

Among 1620 patients who had undergone stool CPE surveillance cultures, only 7.1% of active surveillance at the Emergency Room (ER) and 4.4% of universal surveillance in the Intensive Care Unit (ICU) were stool CPE positive. The transition rates from stool carriers to clinical CPE infections were 29.4% in the ER and 31.3% in the ICU. However, it was significantly high (55.0%) in the initial stool CPE-negative ICU patients. Among the initial stool CPE-positive patients, hypertension (61% vs. 92.3%, P = 0.004), malignancy (28.8% vs. 53.8%, P = 0.027), and mechanical ventilation (25.4% vs. 53.8%, P = 0.011) were significant risk factors for clinical CPE infection. Molecular typing revealed that sequence type (ST) 307 and ST 395 were dominant in K. pneumoniae, and ST 410 was dominant in E. coli isolates.

CONCLUSIONS

Active surveillance showed a higher detection rate than universal stool CPE screening, and one-third of positive stool CPE specimens ultimately developed subsquent clinical CPE infection. According to the molecular typing of the identified CPE strains, in-hospital spread prevailed over external inflow, and the transition rate to clinical CPE was particularly high in the ICU. Therefore, in order to control CPE propagation, not only active surveillance to block inflow from outside, but also continuous ICU monitoring within the hospital is necessary.

Clinical Characteristics of and Risk Factors for Subsequent Carbapenemase-producing Enterobacterales (CPE) Bacteraemia in Rectal CPE Carriers

BACKGROUND

Due to high mortality and limited treatment options, the rise in carbapenemase-producing Enterobacterales (CPE) has become a major concern. This study aimed to evaluate the incidence and characteristics of subsequent CPE bacteraemia in rectal CPE carriers and investigate the risk factors for CPE bacteraemia compared with non-carbapenemase-producing (non-CP) Enterobacterales bacteraemia.

METHODS

A retrospective analysis was conducted on adult patients who were confirmed to have CPE colonisation by stool surveillance culture at a tertiary hospital from January 2018 to February 2022. All episodes of Enterobacterales bacteraemia up to 6 months after CPE colonisation were identified.

RESULTS

Of 1174 patients identified as rectal CPE carriers, 69 (5.8%; 95% CI 4.6-7.3%) experienced subsequent CPE bacteraemia during the 6 months after the diagnosis of CPE colonisation. Colonisation by a Klebsiella pneumoniae carbapenemase (KPC) producer (or CP-K. pneumoniae), colonisation by multiple CPE species, chronic kidney disease and haematological malignancy were independently associated with CPE bacteraemia in CPE carriers. When CPE carriers developed Enterobacterales bacteraemia, the causative agent was more frequently non-CP Enterobacterales than CPE (63.6% vs. 36.4%). Among these patients, colonisation with a KPC producer, CPE colonisation at multiple sites, shorter duration from colonisation to bacteraemia (< 30 days) and recent intraabdominal surgery were independent risk factors for CPE bacteraemia rather than non-CP Enterobacterales bacteraemia.

CONCLUSIONS

In CPE carriers, non-CP Enterobacterales were more often responsible for bacteraemia than CPE. Empirical antibiotic therapy for CPE should be considered when sepsis is suspected in a CPE carrier with risk factors for CPE bacteraemia.

Carbapenem-Resistant Klebsiella pneumoniae Infection and Its Risk Factors in Older Adult Patients

Introduction

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection has recently gained worldwide interest due to limited treatment options and high morbidity and mortality rates. The aim of this study was to determine the risk factors of carbapenem-resistant K. pneumoniae (CRKP) infection in older adult patients.

Material and Methods

This retrospective, single-center study included 132 patients with healthcare-associated CRKP infection (case group) and 150 patients with healthcare-associated carbapenem-susceptible K. pneumoniae (CSKP) infection (control group), aged > 65 years.

Results

In the CRKP and CSKP groups, 79 (59.8%) and 80 (53.3%) patients were males, and the mean ages were 77.8 ± 7.8 and 76.6 ± 7.7 years, respectively. Diabetes mellitus (DM), malignancy, cardiovascular diseases (CVDs), surgical intervention, invasive mechanical ventilation, central venous catheter insertion, parenteral nutrition, hospitalization in the previous 6 months, antibiotic use in the previous 3 months, and exposure to cephalosporins, fluoroquinolones, and carbapenems were significantly more common in the CRKP than the CSKP group (all p < 0.05). The multivariate logistic regression analysis identified malignancy, CVDs, DM, invasive mechanical ventilation, hospitalization in the previous 6 months, ICU admission, and exposure to cephalosporins, quinolones, and carbapenems as independent risk factors for CRKP infection in older adult patients.

Conclusion

DM, malignancy, CVDs, ICU admission, invasive mechanical ventilation, and exposure to ceftriaxone, fluoroquinolones, and carbapenems were independent risk factors for CRKP infection in older adult patients. The identification of risk factors for CRKP infection can help to prevent and treat CRKP infection.

Clinical characteristics of carbapenem-resistant Klebsiella pneumoniae infection/colonisation in the intensive care unit: a 9-year retrospective study

OBJECTIVES

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection/colonisation has been reported in hospitals. The clinical characteristics of CRKP infection/colonisation in the intensive care unit (ICU) have received little attention. This study aims to investigate the epidemiology and extent of K. pneumoniae (KP) resistance to carbapenems, the sources of CRKP patients and CRKP isolates, and the risk factors for CRKP infection/colonisation.

DESIGN

Retrospective single-centre study.

DATA SOURCE

Clinical data were obtained from electronic medical records.

PARTICIPANTS

Patients isolated with KP in the ICU from January 2012 to December 2020.

MAIN OUTCOME MEASURES

The prevalence and changing trend of CRKP were determined. The extent of KP isolates resistance to carbapenems, the specimen types of KP isolates, and the sources of CRKP patients and CRKP isolates were all examined. The risk factors for CRKP infection/colonisation were also assessed.

RESULTS

The rate of CRKP in KP isolates raised from 11.11% in 2012 to 48.92% in 2020. CRKP isolates were detected in one site in 266 patients (70.56%). The percentage of CRKP isolates not susceptible to imipenem increased from 42.86% in 2012 to 98.53% in 2020. The percentage of CRKP patients from general wards in our hospital and other hospitals gradually converged in 2020 (47.06% vs 52.94%). CRKP isolates were mainly acquired in our ICU (59.68%). Younger age (p=0.018), previous admission (p=0.018), previous ICU stay (p=0.008), prior use of surgical drainage (p=0.012) and gastric tube (p=0.001), and use of carbapenems (p=0.000), tigecycline (p=0.005), β-lactams/β-lactamase inhibitors (p=0.000), fluoroquinolones (p=0.033), and antifungal drugs (p=0.011) within the prior 3 months were independent risk factors for CRKP infection/colonisation.

CONCLUSIONS

Overall, the rate of KP isolates resistance to carbapenems increased, and the severity of this resistance significantly increased. Intensive and local infection/colonisation control measures are necessary for ICU patients, especially those with risk factors for CRKP infection/colonisation.

Outbreak of carbapenem-resistant Enterobacterales at a long-term care facility in Seoul, Korea: surveillance and intervention mitigation strategies

OBJECTIVES

Because effective decolonization options are not available, and treatment options are limited, carbapenem-resistant Enterobacterales (CRE) constitute increasingly threatening nosocomial pathogens. To prevent CRE-associated transmission and ensure patient safety, healthcare personnel and everyone in contact with CRE-infected patients must implement stringent infection control practices. This report describes a CRE outbreak, possibly related to a caregiver at a long-term care facility (LTCF), and presents a new surveillance model to improve the infection control of CRE in Seoul, Korea.

METHODS

The Seoul Metropolitan Government surveillance system identified an outbreak of CRE in an LTCF in 2022. We obtained data on the demographic characteristics and contact histories of the inpatients, medical staff, and caregivers. To isolate the inpatients and employees exposed to CRE, we used rectal swab samples and environmental sampling during the study period (May-December 2022).

RESULTS

We identified 18 cluster cases (1 caregiver and 17 inpatients) and 12 sporadic cases with CRE, and conducted a complete 197-day follow-up of all cases in the LTCF's isolation wards.

CONCLUSIONS

This investigation demonstrated that our surveillance model and targeted intervention, based on the cooperation of the municipal government, public health center, and infection control advisory committee, effectively contained the epidemic at the LTCF. Measures to improve the compliance of all employees in LTCFs with infection control guidelines should also be adopted.

Analysis of risk factors associated with healthcare-associated carbapenem-resistant Klebsiella pneumoniae infection in a large general hospital: a case-case-control study

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection is a major public health threat in the world. To inform the prevention and control of CRKP infection in hospitals, this study analyzed the factors associated with CRKP infection and resistance to carbapenems in K. pneumoniae. This case-case-control study was carried out in a large general hospital in China from January 2016 to December 2018, comprising 494 hospitalized patients infected with CRKP (case group 1) and 2429 hospitalized patients infected with carbapenem-susceptible K. pneumoniae (CSKP, case group 2). We selected control groups from hospitalized patients without K. pneumoniae infections for the two case groups separately, with a 1:3 case-control ratio, to analyze the risk factors of the two case groups using the conditional logistic regression. Multivariate analysis showed that the risk factors of CRKP infection were intensive care unit (ICU) admission (odds ratio [OR], 6.85; 95% confidence interval [CI], 4.90-9.58; P < 0.001), respiratory failure (OR, 1.93; 95% CI, 1.34-2.77; P < 0.001), age-adjusted Charlson comorbidity index (aCCI; OR, 1.08; 95% CI, 1.02-1.15; P = 0.007), admission from the Emergency (OR, 1.37; 95% CI, 1.02-1.85; P = 0.036), and imipenem use (OR, 1.80; 95% CI, 1.30-2.49; P < 0.001). Among the aforementioned five risk factors, aCCI (OR, 1.09; 95% CI, 1.06-1.13; P < 0.001) was also identified as a risk factor of CSKP infections in multivariate analysis. The risk factors for resistance to carbapenems in K. pneumoniae were ICU admission, respiratory failure, admission from the Emergency, and imipenem use.

New advances in management and treatment of multidrug-resistant Klebsiella pneumoniae

INTRODUCTION

The management of multidrug-resistant (MDR) Klebsiella pneumoniae (KP) represents a major challenge in the field of infectious diseases. It is associated with a high rate of nosocomial infections with a mortality rate that reaches approximately 50%, even when using an effective antimicrobial therapy. Therefore, combined actions addressing infection control and antibiotic stewardship are required to delay the emergence of resistance. Since new antimicrobial agents targeting MDR-GNB bacteria have been produced during the last years and are now available for physicians to treat MDR, it is fundamental to choose appropriate antimicrobial therapy for K. pneumoniae infection.

AREAS COVERED

The PubMed database was searched to review the most significant recent literature on the topic, including data from articles coming from endemic areas and from the current European and American Guidelines.

EXPERT OPINION

We explore the most effective strategies for prevention of MDR-KP spread and the currently available treatment options, focusing on comparing old strategies and new compounds. We reviewed data concerning newly developed drugs that could play an important role in the future; we also propose a treatment algorithm that could be useful for physicians in daily clinical practice.

Analysis of infections among patients with historical culture positive for extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli or Klebsiella pneumoniae: Is ESBL-targeted therapy always needed?

Objective

Among patients with a history of ESBL infection, uncertainty remains regarding whether all of these patients require ESBL-targeted therapy when presenting with a subsequent infection. We sought to determine the risks associated with a subsequent ESBL infection to help inform empiric antibiotic decisions.

Methods

A retrospective cohort study of adult patients with positive index culture for Escherichia coli or Klebsiella pneumoniae (EC/KP) receiving medical care during 2017 was conducted. Risk assessments were performed to identify factors associated with subsequent infection caused by ESBL-producing EC/KP.

Results

In total, 200 patients were included in the cohort, 100 with ESBL-producing EC/KP and 100 with ESBL-negative EC/KP. Of 100 patients (50%) who developed a subsequent infection, 22 infections were ESBL-producing EC/KP, 43 were other bacteria, and 35 had no or negative cultures. Subsequent infection caused by ESBL-producing EC/KP only occurred when the index culture was also ESBL-producing (22 vs 0). Among those with ESBL-producing index culture, the incidences of subsequent infection caused by ESBL-producing EC/KP versus other bacterial subsequent infection were similar (22 vs 18; P = .428). Factors associated with subsequent infection caused by ESBL-producing EC/KP include history of ESBL-producing index culture, time ≤180 days between index culture and subsequent infection, male sex, and Charlson comorbidity index score >3.

Conclusions

History of ESBL-producing EC/KP culture is associated with subsequent infection caused by ESBL-producing EC/KP, particularly within 180 days after the historical culture. Among patients presenting with infection and a history of ESBL-producing EC/KP, other factors should be considered in making empiric antibiotic decisions, and ESBL-targeted therapy may not always be warranted.

Bloodstream Infections in Patients with Rectal Colonization by Carbapenem-Resistant Enterobacteriaceae: A Prospective Cohort Study

Purpose

Carbapenem-resistant Enterobacteriaceae (CRE) infection has become a concerning threat, especially in hospital settings; however, its phenotypic characterization, association with rectal colonization and subsequent bloodstream infections (BSI) remain to be clarified. This study aimed to investigate the incidence and risk factors of CRE infection in rectal CRE carriers and to understand the clonality of carbapenem-resistant Klebsiella pneumoniae (CRKP) strains and their association with subsequent BSI in these patients.

Patients and Methods

This was a prospectively designed cohort study. Hospitalized patients treated at our institution from April 2019 to October 2020 with intestinal CRE carriage were screened at admission and weekly thereafter until death or discharge from the hospital. Stool and blood samples were obtained for strain growth and mass spectrometry. The colonization and clinical infection isolates were analyzed by antimicrobial susceptibility testing to identify CRE. The clonality of the CRE strains and their corresponding clinical infection strains was studied by whole-genome sequencing to explore the mechanism of drug resistance and evaluate possible transmission. CRE-associated risk factors were analyzed in combination with epidemiological data.

Results

Of the 1203 patients, 85 were colonized by CRE and 21 developed CRE infection, of whom 13 developed CRE bloodstream infection (BSI). Ninety-one CRE strains were isolated from the rectal specimens of the 85 patients. Tracheotomy and chemotherapy in the past three months were independent risk factors for CRE infection in intestinal CRE carriers. ST11-KL64 (92.3%, 24/26) was the most dominant capsule and multilocus sequence typing (MLST) type among clonal CRKP isolates. Single-nucleotide polymorphism clustering showed homology of representative colonization and infection CRKP strain pairs (n=13) in the same patient. One group of leading clones was endemic in surgical intensive care units (ICUs). Twenty-four CRKP strains carried β-lactamase K. pneumonia carbapenemase 2, and 73.1% (19 strains) of CRKP carried mucoid phenotype regulator genes A2 and iucABCD.

Conclusion

In summary, intestinal CRE colonization was detectable at an elevated rate among hospitalized patients and prevalent in ICU patients, with potential rapid horizontal transmission, providing evidence that CRE BSI infection in hospitalized patients might be due to their colonized strains and indicates the correlation between intestinal colonization and BSI.

Infection prevention and control strategies against carbapenem resistant Enterobacteriaceae - a systematic review

Background

Antimicrobial resistance is exponentially worsening, and the spread of prevalent carbapenem resistant Enterobacteriaceae (CRE) is a major contributor to this global concern. Infection prevention and control strategies are increasingly consolidated key tools to control this worldwide problem.

Aim

To identify, collect and analyse available evidence regarding the impact of infection prevention and control strategies on prevalent CRE dissemination.

Methods

Pubmed®, Scopus® and Web of Science® were searched systematically for articles published between 1th January 2017 and 30th June 2020, guided by the research question 'What are the most effective and efficient strategies to prevent and control infection/colonisation caused by Carbapenem resistant Escherichia coli and Carbapenem resistant Klebsiella pneumoniae?'.

Findings

Eleven thousand six hundred and thirty-five publications were found, but after applying the inclusion and exclusion criteria, only 30 were selected. The majority of reviewed studies (n = 24) were performed in outbreak situations, 26 studies occurred in acute care units and of those, 17 in intensive care units . From the set of implemented infection prevention and control measures, in 29 studies surveillance cultures were applied, in 23 studies patients were isolated or cohorted and, in general, all described the implementation of standard and contact precaution measures.

Conclusion

This systematic review underlines the importance of infection prevention and control strategies in CRE dissemination, standing out the need of further studies outside outbreak and intensive care units contexts. Investment increments and training and educating of all involved are also important contributors to shift this problem, but still with relevant gaps in their implementation, in all types of care units, that need to be addressed.

A Novel Risk Predictive Scoring Model for Predicting Subsequent Infection After Carbapenem-Resistant Gram-Negative Bacteria Colonization in Hematological Malignancy Patients

Background

This study investigated the high-risk factors associated with the increased vulnerability for subsequent clinical CR-GNB infection in carbapenem-resistant Gram-negative bacteria (CR-GNB)-colonized hematological malignancy (HM) patients and built a statistical model to predict subsequent infection.

Method

All adult HM patients with positive rectoanal swabs culture for CR-GNB between January 2018 and June 2020 were prospectively followed to assess for any subsequent CR-GNB infections and to investigate the risk factors and clinical features of subsequent infection.

Results

A total of 392 HM patients were enrolled. Of them, 46.7% developed a subsequent clinical CR-GNB infection, with 42 (10.7%) cases of confirmed infection and 141 (36%) cases of clinically diagnosed infection. Klebsiella pneumoniae was the dominant species. The overall mortality rate of patients colonized and infected with CR-GNB was 8.6% and 43.7%. A multivariate analysis showed that remission induction chemotherapy and the duration of agranulocytosis, mucositis, and hypoalbuminemia were significant predictors of subsequent infection after CR-GNB colonization. According to our novel risk-predictive scoring model, the high-risk group were >3 times more likely to develop a subsequent infection in comparison with the low-risk group.

Conclusion

Our risk-predictive scoring model can early and accurately predict a subsequent CR-GNB infection in HM patients with CR-GNB colonization. The early administration of CR-GNB-targeted empirical therapy in the high-risk group is strongly recommended to decrease their mortality.

Global Threat of Carbapenem-Resistant Gram-Negative Bacteria

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

Multidrug-Resistant Gram-Negative Bacteria: Infection Prevention and Control Update

Multidrug-resistant gram-negative bacteria (MDR-GNB) pose one of the greatest challenges to health care today because of their propensity for human-to-human transmission and lack of therapeutic options. Containing the spread of MDR-GNB is challenging, and the application of multifaceted infection control bundles during an evolving outbreak makes it difficult to measure the relative impact of each measure. This article will review the utility of various infection control measures in containing the spread of various MDR-GNB and will provide the supporting evidence for these interventions.

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.

Risk factors for carbapenem-resistant Klebsiella pneumoniae infection and associated clinical outcomes

OBJECTIVE

To evaluate the risk factors and clinical outcomes of carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae) (CRKP) infection.

MATERIALS AND METHODS

A case-control study was performed from January 2017 to September 2017. The risk factors and clinical outcomes of CRKP cases (n = 91) were compared with those of the controls infected with carbapenem-susceptible K. pneumoniae (CSKP) (n = 91). Antibiotic susceptibility was determined using Etest while the type of bacteria was identified by Vitek 2.

RESULTS

CRKP infection was associated with prior use of carbapenems, β-lactam antibiotics, tigecycline, and hormones; complications with cerebrovascular lesions; chronic obstructive pulmonary disease; as well as prolonged hospitalization. Multivariable analysis showed that the use of carbapenem independently correlates with carbapenem resistance in the multivariable analysis. Carbapenem resistance, mechanical ventilation, tracheotomy, deep vein cannulation, indwelling urinary tract catheter, ICU treatment, and high Acute Physiology, Age, Chronic Health Evaluation II (APACHE II) scores were related to in-hospital mortality.

CONCLUSION

CRKP is a widely spread pathogen associated with high in-hospital mortality. Minimizing the use of antimicrobials, specifically the carbapenems, may be effective to reduce CRKP infection.

Carbapenem-Resistant Enterobacterales in Long-Term Care Facilities: A Global and Narrative Review

The emergence of carbapenem-resistant Enterobacterales (CRE) has become a major public health concern. Moreover, its colonization among residents of long-term care facilities (LTCFs) is associated with subsequent infections and mortality. To further explore the various aspects concerning CRE in LTCFs, we conducted a literature review on CRE colonization and/or infections in long-term care facilities. The prevalence and incidence of CRE acquisition among residents of LTCFs, especially in California, central Italy, Spain, Japan, and Taiwan, were determined. There was a significant predominance of CRE in LTCFs, especially in high-acuity LTCFs with mechanical ventilation, and thus may serve as outbreak centers. The prevalence rate of CRE in LTCFs was significantly higher than that in acute care settings and the community, which indicated that LTCFs are a vital reservoir for CRE. The detailed species and genomic analyses of CRE among LTCFs reported that Klebsiella pneumoniae is the primary species in the LTCFs in the United States, Spain, and Taiwan. KPC-2-containing K. pneumoniae strains with sequence type 258 is the most common sequence type of KPC-producing K. pneumoniae in the LTCFs in the United States. IMP-11- and IMP-6-producing CRE were commonly reported among LTCFs in Japan. OXA-48 was the predominant carbapenemase among LTCFs in Spain. Multiple risk factors associated with the increased risk for CRE acquisition in LTCFs were found, such as comorbidities, immunosuppressive status, dependent functional status, usage of gastrointestinal devices or indwelling catheters, mechanical ventilation, prior antibiotic exposures, and previous culture reports. A high CRE acquisition rate and prolonged CRE carriage duration after colonization were found among residents in LTCFs. Moreover, the patients from LTCFs who were colonized or infected with CRE had poor clinical outcomes, with a mortality rate of up to 75% in infected patients. Infection prevention and control measures to reduce CRE in LTCFs is important, and could possibly be controlled via active surveillance, contact precautions, cohort staffing, daily chlorhexidine bathing, healthcare-worker education, and hand-hygiene adherence.

Imipenem/cilastatin/relebactam: A new carbapenem β-lactamase inhibitor combination

PURPOSE

The pharmacology, pharmacokinetics, pharmacodynamics, antimicrobial activity, efficacy, safety, and current regulatory status of imipenem/cilastatin/relebactam are reviewed.

SUMMARY

Imipenem/cilastatin/relebactam is a newly approved anti-infective combination of a well-established β-lactam and a new β-lactamase inhibitor for the treatment of complicated urinary tract infections (cUTIs), including pyelonephritis, and complicated intra-abdominal infections (cIAIs) caused by susceptible gram-negative bacteria in patients 18 years of age or older with limited or no alternative treatment options. The antibiotic is also indicated for the treatment of hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia (VABP). The antibiotic is active in vitro against a wide range of pathogens, including multidrug-resistant (MDR) Pseudomonas aeruginosa and carbapenem-resistant Enterobacterales (CRE) such as Klebsiella pneumoniae carbapenemase. The addition of relebactam does not restore the activity of imipenem against metallo-β-lactamase (MBL)-producing Enterobacterales and carbapenem-resistant Acinetobacter baumannii. Two phase 3 clinical trials of imipenem/cilastatin/relebactam were conducted. In the RESTORE-IMI 1 trial, the efficacy and safety of imipenem/cilastatin/relebactam was found to be comparable to that of imipenem/cilastatin plus colistin for the treatment of infections caused by imipenem-nonsusceptible gram-negative bacteria in patients with HABP/VABP, cUTIs, and cIAIs, with a significantly lower incidence of nephrotoxicity reported with the new antibiotic. The RESTORE-IMI 2 trial demonstrated the noninferiority of imipenem/cilastatin/relebactam to piperacillin/tazobactam for the treatment of HABP/VABP. Commonly reported adverse events in clinical trials included anemia, elevated liver enzymes, electrolyte imbalances, nausea, vomiting, diarrhea, headache, fever, phlebitis and/or infusion-site reactions, and hypertension.

CONCLUSION

Imipenem/cilastatin/relebactam is a new β-lactam/β-lactamase inhibitor combination with activity against MDR gram-negative bacteria, including many CRE but excluding MBL-producing Enterobacterales and carbapenem-resistant Acinetobacter baumannii. It is approved for the treatment of cUTIs, cIAIs, and HABP/VABP.

Microbiota-mediated protection against antibiotic-resistant pathogens

Colonization by the microbiota provides one of our most effective barriers against infection by pathogenic microbes. The microbiota protects against infection by priming immune defenses, by metabolic exclusion of pathogens from their preferred niches, and through direct antimicrobial antagonism. Disruption of the microbiota, especially by antibiotics, is a major risk factor for bacterial pathogen colonization. Restoration of the microbiota through microbiota transplantation has been shown to be an effective way to reduce pathogen burden in the intestine but comes with a number of drawbacks, including the possibility of transferring other pathogens into the host, lack of standardization, and potential disruption to host metabolism. More refined methods to exploit the power of the microbiota would allow us to utilize its protective power without the drawbacks of fecal microbiota transplantation. To achieve this requires detailed understanding of which members of the microbiota protect against specific pathogens and the mechanistic basis for their effects. In this review, we will discuss the clinical and experimental evidence that has begun to reveal which members of the microbiota protect against some of the most troublesome antibiotic-resistant pathogens: Klebsiella pneumoniae, vancomycin-resistant enterococci, and Clostridioides difficile.

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.

Epidemiology and risk factors of rectal colonization of carbapenemase-producing Enterobacteriaceae among high-risk patients from ICU and HSCT wards in a university hospital

Background

Nosocomial carbapenemase-producing Enterobacterieceae (CPE) infections constitute a major global health concern and are associated with increased morbidity and mortality. Rectal colonization with CPE is a risk factor for bacterial translocation leading to subsequent endogenous CPE infections. This prospective observational study was aimed to investigate the prevalence and epidemiology of rectal colonization of CPE, the carbapenemase genotypes, and to identify the independent risk factors for the acquisition of CPE colonization in high-risk patients from ICU and HSCT wards in a university hospital in China.

Methods

In a prospective cohort study, 150 fecal samples from rectal swabs were consecutively obtained for inpatients from the intensive care unit (ICU) and hematopoietic stem cell transplantation (HSCT) wards from November 2018 to May 2019, and screening test for CPE was conducted by using prepared in-house trypsin soybean broth (TSB) selective media and MacConkey agar. Antimicrobial susceptibility was determined by the broth microdilution method and carbapenemase genes were characterized by both the GeneXpert Carba-R and PCR for bla_KPC, bla_NDM, bla_IMP, bla_VIM and bla_OXA. Multi-locus sequence typing (MLST) was employed to characterize the genetic relationships among the carbapenemase-producing K. Pneumonia (CPKP) isolates. In order to further investigate the risk factors and clinical outcomes of CPE colonization, a prospective case-control study was also performed.

Results

Twenty-six suspected CPE strains, including 17 Klebsiella pneumoniae, 6 Escherichia coli, 1 Citrobacter freundii, 1 Enterobacter Kobe, and 1 Raoultella ornithinolytica, were identified in 25 non-duplicated rectal swab samples from 25 patients, with a carriage rate of 16.67% (25/150). Through GeneXpert Carba-R and subsequent PCR and sequencing, all the suspected CPE isolates were identified to be positive for the carbapenemase genes, of which 17 were bla_KPC-carriers, and another 9 were bla_NDM-producers. MLST designated all the CPKP isolates to be ST11 clone. Multivariate analysis indicated that urinary system diseases, operation of bronchoscopy, and combined use of antibiotics were independent risk factors for acquiring CPE colonization in high-risk patients from the ICU and HSCT wards.

Conclusions

This study revealed a high prevalence of rectal CPE colonization in high-risk patients from ICU and HSCT wards, and a predominant colonization of the KPC-producing K. pneumoniae clone ST11. Stricter infection control measures are urgently needed to limit the dissemination of CPE strains, especially in patients who were afflicted by urinary system diseases, have underwent bronchoscopy, and were previously exposed to combined antibiotic use.

Positivity of Carbapenemase-producing Enterobacteriaceae in Patients Following Exposure within Long-term Care Facilities in Seoul, Korea

BACKGROUND

Carbapenemase-producing Enterobacteriaceae (CPE) are emerging as a worldwide threat. Long-term care facilities (LTCFs) are considered a reservoir for CPE and play a central role in transmission to acute care hospitals. We investigated the CPE positivity in patients exposed to CPE in LTCFs. Furthermore, we analyzed the CPE positivity rates in the environment exposed to CPE.

METHODS

We collected rectal swab specimens from patients residing in LTCFs who were exposed to CPE. Environmental sampling was performed by infection control practitioners from sites classified as patient private space, common space in the patient room, common space other than patient rooms, and nursing station. Each sample was cultured on a Chrom Klebsiella pneumoniae carbapenemase (KPC) agar for CPE screening. The positive isolates were subjected to a polymerase chain reaction to identify the presence of bla_KPC, bla_VIM, bla_IMP, bla_OXA-48, and bla_NDM and determine CPE genotype.

RESULTS

From 65 index cases, a total of 24 hospitals and 481 patients were enrolled; 414 patients who had resided in the same patient room as a patient with confirmed CPE and 67 patients who were newly admitted to that patient room. A total of 117 (24.3%) patients were positive for CPE among which 93 (22.5%, 93/414) were already admitted patients and 24 (35.8%, 24/67) were newly admitted patients. A total of 163 CPEs were detected and K. pneumoniae (n = 104, 63.8%) was the most common bacteria followed by Escherichia coli (n = 43, 26.4%) and Citrobacter koseri (n = 11, 6.7%). Environmental sampling was performed in 24 hospitals and 604 sites. A total of 12 sites (2.0%) were positive for CPE and sink in the nursing station (n = 6, 4.2%) was the most contaminated space.

CONCLUSION

CPE colonization rates in patients exposed to CPE in LTCFs were higher than those found in acute care hospitals. Proper infection control measures for detecting and reducing CPE colonization in patients residing in LTCFs are required. Newly admitted patients could also be carriers; therefore, infection control for newly admitted patients also needs to be thorough.

Derivation of a Model to Guide Empiric Therapy for Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infection in an Endemic Area

BACKGROUND

Appropriate therapy for carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infection (BSI) is often given late in the course of infection, and strategies for identifying CRKP BSI earlier are needed.

METHODS

A retrospective case-control study was performed at a tertiary care hospital, university hospital, and community hospital in Bronx, New York. All participants had a blood culture sent and received an antibiotic within 48 hours of the culture. The case group (n = 163) had a blood culture with CRKP. The control group (n = 178) had a blood culture with carbapenem-susceptible Klebsiella. Data were obtained by electronic or conventional medical record abstraction. A multiple logistic regression model was built to identify associated factors and develop a clinical model for CRKP BSI. Model performance characteristics were estimated using a 10-fold cross-validation analysis.

RESULTS

A prior nonblood culture with carbapenem-resistant Enterobacteriaceae, skilled nursing facility (SNF) residence, mechanical ventilation, and admission >3 days were strongly associated risk factors. A significant interaction led to development of separate clinical models for subjects admitted <3 days at the time of positive blood culture from those admitted at least 3 days. The derived models had a good ability to discriminate between subjects with and without CRKP BSI. A clinical classification rule to guide therapy can prioritize sensitivity or specificity.

CONCLUSIONS

Prior nonblood cultures showing resistance and exposure to SNF and health care settings are factors associated with carbapenem resistance. The clinical classification rules derived in this work should be validated for ability to guide therapy.

Five-year change of prevalence and risk factors for infection and mortality of carbapenem-resistant Klebsiella pneumoniae bloodstream infection in a tertiary hospital in North China

BACKGROUND

There are few studies focused on carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infection (BSI). The aim of this study is to identify the prevalence and risk factors for infection and mortality of CRKP BSI.

METHODS

Susceptibility of Klebsiella pneumoniae (KP) isolated from blood samples and the proportion of CRKP were recorded annually. One hundred sixty-four patients with CRKP and 328 with carbapenem-susceptible Klebsiella pneumoniae (CSKP) BSI were categorized as the case group and control group to identify risk factors for CRKP infection and mortality by univariable analysis and multivariable logistic-regression analysis.

RESULTS

The proportion and mortality of CRKP BSI increased significantly, with the percentage of KP in BSI increasing from 7 to 12% from 2014 to 2019 with a concomitant resistance to meropenem increasing from 16.7 to 41.8%. Compared with CSKP group, patients in CRKP group had longer hospitalization time before bacteremia (median 14 vs 4, P < 0.001) and longer total hospitalization time (median 31 vs 19, P < 0.001). The proportion of admission to ICU was higher (70.7% vs 17.7%, P < 0.001), and APACHE II score was higher (median 12 vs 8, P < 0.001). The mortality in CRKP group was 43.9% (72/164), while 14.9% (49/328) in CSKP group (p < 0.001). KP detection in other sites(P = 0.036, OR 1.964), blood purification(P = 0.018, OR 3.326), bronchoscopy(P = 0.011, OR 5.423), surgery (P = 0.001, OR 3.084), carbapenem use(P = 0.001, OR 3.395), tigecycline use(P = 0.006, OR 4.595) were independent risk factors for CRKP BSI. Previous hospitalization (P = 0.048, OR 2.755), long hospitalization (P = 0.003, OR 1.035), bone marrow puncture (P = 0.037, OR3.856), use of β-lactamase inhibitor (P = 0.005, OR 3.890) were independent risk factors for mortality in CRKP BSI.

CONCLUSION

The prevalence and mortality of CRKP BSI are still increasing. Timely treatment of KP infection in other site, strengthening the hospital infection control of blood purification, bronchoscopy and surgery, control the use of carbapenem and tigecycline, may help to prevent CRKP BSI. More preventative hospital resources are needed for severely ill patients with prolonged hospitalizations and intensive care.

Risk Factors for Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infections and Outcomes

Purpose

The incidence of carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infections (BSIs) is increasing globally; however, little has been reported on the risk factors and outcomes of CRKP BSIs in central China. This study aimed to determine the clinical risk factors for CRKP BSIs and the outcomes of CRKP BSIs.

Patients and Methods

We performed a case-control study of 239 patients with K. pneumoniae BSIs who were treated at Henan Provincial People’s Hospital between July 2017 and July 2018. The cases (n=98, 41%) had CRKP BSIs, and the controls (n=141, 59%) had non-carbapenem-resistant K. pneumoniae (non-CRKP) BSIs. Antimicrobial sensitivity was determined using automated broth microdilution and an agar disk diffusion method. Data were obtained from clinical and laboratory records. Multivariate logistic regression and Pearson chi-square tests were used to identify clinical factors and outcomes associated with carbapenem resistance.

Results

Risk factors for carbapenem resistance included recent carbapenem use (odds ratio [OR]: 9.98, 95% confidence interval [CI]: 5.2–17.1, P<0.001), invasive procedures (OR: 11.1, 95% CI: 3.3–37.7, P<0.001), and pre-existing diseases of the digestive system (OR: 8.22, 95% CI: 1.73–39.2, P=0.008). Treatment failure was more frequent in the cases (84.7%) than in the controls (32.6%).

Conclusion

Exposure to antibiotics, especially carbapenems, and invasive procedures were the major risk factors for carbapenem resistance among patients with K. pneumoniae BSIs. Strict control measures should be implemented to prevent the emergence and spread of CRKP.

Commensal Bacteroidetes protect against Klebsiella pneumoniae colonization and transmission through IL-36 signalling

The microbiota primes immune defences but the identity of specific commensal microorganisms that protect against infection is unclear. Conversely, how pathogens compete with the microbiota to establish their host niche is also poorly understood. In the present study, we investigate the antagonism between the microbiota and Klebsiella pneumoniae during colonization and transmission. We discover that maturation of the microbiota drives the development of distinct immune defence programmes in the upper airways and intestine to limit K. pneumoniae colonization within these niches. Immune protection in the intestine depends on the development of Bacteroidetes, interleukin (IL)-36 signalling and macrophages. This effect of Bacteroidetes requires the polysaccharide utilization locus of their conserved commensal colonization factor. Conversely, in the upper airways, Proteobacteria prime immunity through IL-17A, but K. pneumoniae overcomes these defences through encapsulation to effectively colonize this site. Ultimately, we find that host-to-host spread of K. pneumoniae occurs principally from its intestinal reservoir, and that commensal-colonization-factor-producing Bacteroidetes are sufficient to prevent transmission between hosts through IL-36. Thus, our study provides mechanistic insight into when, where and how commensal Bacteroidetes protect against K. pneumoniae colonization and contagion, providing insight into how these protective microorganisms could be harnessed to confer population-level protection against K. pneumoniae infection.

Risk factors for carbapenem-resistant Klebsiella pneumoniae infection: A meta-analysis

OBJECTIVES

Rates of nosocomial infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) have increased. A meta-analysis was conducted to explore risk factors for CRKP infection in order to provide a theoretical basis for reducing the CRKP infection rate and actively preventing CRKP infection.

METHODS

Online databases, including PubMed, EMBASE, OVID, ClinicalKey, CNKI, CBM, Wanfang Database and CHKD, were searched from inception up to 31 October 2018 for articles regarding risk factors for CRKP infection. Relevant articles were retrieved, supplemented by retrospective and manual search literature. RevMan 5.3 software was used for statistical analysis.

RESULTS

A total of 30 articles comprising 5075 cases were included in the study, of which 24 were in English and 6 were in Chinese. The results showed that age, sex and diabetes mellitus were not associated with CRKP infection. The odds ratio (95% confidence interval) of risk factors for CRKP infection were as follows: immunosuppression, 1.47 (1.14-1.90); ICU admission, 3.25 (2.36-4.47); antibiotic exposure, 2.53 (1.56-4.11); carbapenem exposure, 3.99 (2.86-5.56); quinolone exposure, 1.75 (1.38-2.22); glycopeptide exposure, 3.08 (1.93-4.91); β‑lactam/β‑lactamase inhibitor (BL/BLI) exposure, 2.28 (1.37-3.80); surgery, 1.59 (1.08-2.34); mechanical ventilation, 2.91 (1.96-4.31); central venous catheterisation, 2.93 (2.00-4.28); indwelling catheter, 2.62 (1.65-4.17); and nasogastric intubation, 2.38 (1.22-4.62).

CONCLUSION

Immunosuppression, ICU admission, antibiotic exposure (including carbapenems, quinolones, glycopeptides and BL/BLIs), surgery, mechanical ventilation, central venous catheterisation, indwelling catheter and nasogastric intubation were identified as risk factors for CRKP infection and should to be considered in clinical practice.

Screening for carriage of carbapenem-resistant Enterobacteriaceae in settings of high endemicity: a position paper from an Italian working group on CRE infections

Introduction

A variety of national and international guidelines exist around the management of carbapenem resistant Enterobacteriaceae (CREs), but some of these are several years old and do not reflect current epidemiology and they also do not necessarily give pragmatic advice around active surveillance of CREs in countries with a high burden of cases and limited resources. This paper aims to provide a best practice position paper to guide active surveillance in a variety of scenarios in these settings, and discusses which patients should be screened, what methods could be used for screening, and how results might influence infection prevention interventions.

Methods

This paper was developed as a result of a series of meetings of expert opinion leaders representing the major infectious disease and infection prevention societies in Italy and having the endorsement of AMCLI (Italian Association of Clinical Microbiology) and SITA (Italian Society for Anti-infective Therapy). There was no attempt to undertake a full systematic review of the evidence, as it was felt that this was inadequate to inform a pragmatic view on the best way forward based on current epidemiology and infection rates.

Key recommendations

Key recommendations focus on the urgent need to promote measures to prevent transmission and infection, focusing on high risk patients and clinical areas, as well as outbreak situations. Active surveillance leading to appropriate infection prevention precautions plays a major role in this.

Conclusions

There are limited national or international guidelines giving pragmatic advice on the most appropriate measures for active surveillance and management of colonized patients in a high-burden setting such as Italy. While individual hospitals and regions will need to formulate their own policies based on local epidemiology, this position paper attempts to highlight current best practice in this area and provide pragmatic advice for clinicians, infection prevention staff, and healthcare managers.

Pharmacokinetics, Safety, and Tolerability of Single and Multiple Doses of Relebactam, a β-Lactamase Inhibitor, in Combination with Imipenem and Cilastatin in Healthy Participants

Relebactam is a novel class A and C β-lactamase inhibitor that is being developed in combination with imipenem-cilastatin for the treatment of serious infections with Gram-negative bacteria. Here we report on two phase 1 randomized, double-blind, placebo-controlled pharmacokinetics, safety, and tolerability studies of relebactam administered with or without imipenem-cilastatin to healthy participants: (i) a single-dose (25 to 1,150 mg) and multiple-dose (50 to 625 mg every 6 h [q6h] for 7 to 14 days) escalation study with men and (ii) a single-dose (125 mg) study with women and elderly individuals.

Relebactam is a novel class A and C β-lactamase inhibitor that is being developed in combination with imipenem-cilastatin for the treatment of serious infections with Gram-negative bacteria. Here we report on two phase 1 randomized, double-blind, placebo-controlled pharmacokinetics, safety, and tolerability studies of relebactam administered with or without imipenem-cilastatin to healthy participants: (i) a single-dose (25 to 1,150 mg) and multiple-dose (50 to 625 mg every 6 h [q6h] for 7 to 14 days) escalation study with men and (ii) a single-dose (125 mg) study with women and elderly individuals. Following single- or multiple-dose intravenous administration over 30 min, plasma relebactam concentrations declined biexponentially, with a terminal half-life (t_1/2) ranging from 1.35 to 1.85 h independently of the dose. Exposures increased in a dose-proportional manner across the dose range. No clinically significant differences in pharmacokinetics between men and women, or between adult and elderly participants, were observed. Urine pharmacokinetics demonstrated that urinary excretion is the major route of relebactam elimination. No drug-drug interaction between relebactam and imipenem-cilastatin was observed, and the observed t_1/2 values for relebactam, imipenem, and cilastatin were comparable, thus supporting coadministration. Relebactam administered alone or in combination with imipenem-cilastatin was well tolerated across the dose ranges studied. No serious adverse events or deaths were reported. The pharmacokinetic profile and favorable safety results supported q6h dosing of relebactam with imipenem-cilastatin in clinical treatment trials.

Ambulance vehicles as a source of multidrug-resistant infections: a multicenter study in Assiut City, Egypt

Background

Ambulances may represent a potential source of infection to patients, patients’ relatives, and paramedical staffs. In this study, we analyzed the extent of bacterial contamination in ambulance vehicles and measured the degree of antimicrobial resistance among isolated pathogens.

Materials and methods

Twenty-five vehicles were included and 16 sampling points were swabbed in each vehicle. Then the swabs were immediately transferred to the laboratory to identify bacterial contaminants utilizing standard microbiological procedures and API^® systems. Antibiotic susceptibility testing and screening for methicillin-resistant staphylococci and extended spectrum β-lactamases (ESBLs)-producing Gram-negative rods were carried out.

Results

A total of 400 samples were collected, 589 bacteria were isolated and 286 (48.6%) of the isolates were potentially pathogenic. The highest contamination rate with pathogenic bacteria was detected in suction devices (75.8%) and stethoscopes (67.7%). Staphylococci were the most frequently detected microorganisms (n=184) followed by Klebsiella spp. (49), Escherichia coli (40), Citrobacter spp. (7), and Proteus spp. (6). Staphylococci were mostly sensitive to vancomycin, whereas Gram-negative bacteria were sensitive to imipenem. Overall, 46.1% of Staphylococcus aureus were methicillin resistant, whereas 20.4% of the coagulase-negative staphylococci were methicillin resistant. Moreover, 36.7% of Klebsiella spp. and 27.5% of E. coli were ESBL producers.

Conclusion

Our study provides evidence that ambulances represent a source of prehospital multidrug-resistant infections.

A Systematic Review and Meta-analyses of the Clinical Epidemiology of Carbapenem-Resistant Enterobacteriaceae

Carbapenem-resistant Enterobacteriaceae (CRE) are major health care-associated pathogens and responsible for hospital outbreaks worldwide. To prevent a further increase in CRE infections and to improve infection prevention strategies, it is important to summarize the current knowledge about CRE infection prevention in hospital settings. This systematic review aimed to identify risk factors for CRE acquisition among hospitalized patients. In addition, we summarized the environmental sources/reservoirs and the most successful infection prevention strategies related to CRE. A total of 3,983 potentially relevant articles were identified and screened. Finally, we included 162 studies in the systematic review, of which 69 studies regarding risk factors for CRE acquisition were included in the random-effects meta-analysis studies. The meta-analyses regarding risk factors for CRE acquisition showed that the use of medical devices generated the highest pooled estimate (odds ratio [OR] = 5.09; 95% confidence interval [CI] = 3.38 to 7.67), followed by carbapenem use (OR = 4.71; 95% CI = 3.54 to 6.26). To control hospital outbreaks, bundled interventions, including the use of barrier/contact precautions for patients colonized or infected with CRE, are needed. In addition, it is necessary to optimize the therapeutic approach, which is an important message to infectious disease specialists, who need to be actively involved in a timely manner in the treatment of patients with known CRE infections or suspected carriers of CRE.

Epidemiology of Carbapenem-Resistant Klebsiella pneumoniae in a Network of Long-Term Acute Care Hospitals

Background

The rapid emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) represents a major public health threat, including in the long-term acute care hospital (LTACH) setting. Our objective in this study was to describe the epidemiologic characteristics of CRKP in a network of US LTACHs.

Methods

An observational study was performed among 64 LTACHs from January 2014 to March 2015. Clinical cultures were included, with the first CRKP isolate recovered from each patient per study quarter evaluated. LTACH and geographic area-based CRKP prevalence and clinical and microbiologic characteristics were described.

Results

A total of 3846 K. pneumoniae cultures were identified, with an overall carbapenem resistance rate of 24.6%. There were significant differences in CRKP rates across geographic regions, with the highest in the West (42.2%). Of 946 CRKP isolates, 507 (53.6%) were from a respiratory source, 350 (37.0%) from a urinary source, and 9 (9.4%) from blood. Among 821 unique patients with CRKP colonization or infection, the median age was 73 years. There was a high prevalence of respiratory failure (39.8%) and the presence of a central venous catheter (50.9%) or tracheostomy (64.8%). Resistance rates of CRKP isolates were high for amikacin (59.2%) and fluoroquinolones (>97%). The resistance rate to colistin/polymyxin B was 16.1%.

Conclusions

Nearly 25% of K. pneumoniae clinical isolates in a US network of LTACHs were CRKP. Expansion of national surveillance efforts and improved communication among LTACHs and acute care hospitals will be critical for reducing the continued emergence of CRKP across the healthcare continuum.

Clinical and molecular characteristics, risk factors and outcomes of Carbapenem-resistant Klebsiella pneumoniae bloodstream infections in the intensive care unit

Background

To analyze the clinical characteristics and outcomes of carbapenem-resistant Klebsiella pneumoniae (CRKp) and carbapenem-susceptible K. pneumoniae (CSKp) bloodstream infections (BSIs), and to study the risk factors for development of CRKp BSI and K. pneumoniae BSI-related mortality.

Methods

A retrospective case control study of patients with K. pneumoniae BSI was conducted in the intensive care unit of the First Affiliated Hospital, Medical of College, Zhejiang University from January 2013 to December 2014. Carbapenem resistance was defined in accordance with the Clinical and Laboratory Standards Institute 2016 guidelines. Risk factors for the development of CRKp BSI and risk factors for mortality due to K. pneumoniae BSI were assessed. Virulence genes were detected by polymerase chain reaction assay.

Results

In total, 48 patients were enrolled in the study, including 31 (65%) patients with CRKp BSI and 17 (35%) patients with CSKp BSI. CSKp infection was associated with more severe clinical symptoms, particularly a higher serum creatinine level (165.06 ± 127.01 in the CSKp group vs. 93.77 ± 84.35 μmol/L in the CRKp group, p = 0.039), but there was no significant difference in prognosis between the CSKp and CRKp groups. On multivariate analysis, indwelling central venous catheter (p = 0.045) was the only factor independently associated with CRKp bacteremia. However, the mortality of K. pneumoniae BSI patients was not correlated with carbapenem resistance. In addition, the isolates had diverse clonality and different origins. The frequency of detection of the allS and magA virulence genes was higher in the CSKp group than in the CRKp group (alls p = 0.04; magA p = 0.047).

Conclusions

Patients in the CSKp group experienced more severe clinical symptoms, although mortality did not differ significantly between the CRKp and CSKp groups. An indwelling central venous catheter was the only factor independently associated with CRKp BSI. The mortality of patients with K. pneumoniae BSI was not associated with carbapenem resistance. The frequency of virulence genes was higher in the CSKp group than in the CRKp group.

A New Take on an Old Remedy: Generating Antibodies against Multidrug-Resistant Gram-Negative Bacteria in a Postantibiotic World

With the problem of multidrug-resistant Gram-negative pathogens becoming increasingly dire, new strategies are needed to protect and treat infected patients. Though abandoned in the past, monoclonal antibody therapy against Gram-negative bacteria remains a potential solution and has potential advantages over the broad-spectrum antibiotics they were once replaced by. This Perspective reviews the prospect of utilizing monoclonal antibody therapy against these pathogens, as well as the challenges of doing so and the current therapy targets under investigation.

Carbapenem-resistant Klebsiella pneumoniae in Barbados: Driving change in practice at the national level

Introduction

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is of growing concern globally. The risk for transmission of antimicrobial resistant organisms across several continents to the Caribbean is a real one given its tourism industry. After a cluster of cases of CRKP were detected, several studies detailed in this report were initiated to better characterize the problem.

Methods

A hospital-wide point prevalence study and active surveillance were performed at Queen Elizabeth Hospital (QEH) in Barbados in 2013 to assess the prevalence of CRKP infection/colonization. Following this, a 1-year longitudinal study measured the prevalence of CRKP isolates in the hospital and across all healthcare facilities in the country.

Results

In 2013, eleven viable isolates of CRKP from cluster of cases were sent for molecular epidemiology studies. When sequenced, they were found to be the ST-258 clone. Identification of a cluster of cases of CRKP ST-258/512 clones indicated person-to-person transmission. In September 2013, the hospital-wide point prevalence study revealed 18% of patients (53/299) at the hospital were either colonized or infected with CRKP. The infection to colonization ratio was 1:7. Patients who were infected/colonized vs. non-colonized were older (64.7 vs. 48.7 years, p<0.0001), were hospitalized longer (42.5 days vs. 27 days, p = 0.0042), were more likely to have an invasive device (66% vs. 32%, p<0.0001), especially urinary catheters (55% vs. 24%, p<0.0001), and were more likely to have used antimicrobials within the prior 14 days (91% vs. 46%, p<0.0001). Specific antimicrobials, including fluoroquinolones and piperacillin-tazobactam, were significantly associated with infection/colonization. In 2014, the 12-month period prevalence of CRKP in Barbados was 49.6 per 100,000 population and of blood stream infections was 3.2 per 100,000 population.

Conclusions

This point prevalence study identified patients at-risk of acquisition of CRKP and allowed QEH to implement interventions aimed at decreasing the prevalence of CRKP. Organization of a National and regional Infection Prevention and Control Committee in 2014 aimed to strengthen antimicrobial resistance surveillance programs across the English-speaking Caribbean were established.

The Epidemiology of Carbapenem-Resistant Enterobacteriaceae: The Impact and Evolution of a Global Menace

Carbapenem-resistant Enterobacteriaceae (CRE) are a serious public health threat. Infections due to these organisms are associated with significant morbidity and mortality. Mechanisms of drug resistance in gram-negative bacteria (GNB) are numerous; β-lactamase genes carried on mobile genetic elements are a key mechanism for the rapid spread of antibiotic-resistant GNB worldwide. Transmissible carbapenem-resistance in Enterobacteriaceae has been recognized for the last 2 decades, but global dissemination of carbapenemase-producing Enterobacteriaceae (CPE) is a more recent problem that, once initiated, has been occurring at an alarming pace. In this article, we discuss the evolution of CRE, with a focus on the epidemiology of the CPE pandemic; review risk factors for colonization and infection with the most common transmissible CPE worldwide, Klebsiella pneumoniae carbapenemase-producing K. pneumoniae; and present strategies used to halt the striking spread of these deadly pathogens.

Modifiable Risk Factors for the Spread of Klebsiella pneumoniae Carbapenemase-Producing Enterobacteriaceae Among Long-Term Acute-Care Hospital Patients

OBJECTIVE To identify modifiable risk factors for acquisition of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae (KPC) colonization among long-term acute-care hospital (LTACH) patients. DESIGN Multicenter, matched case-control study. SETTING Four LTACHs in Chicago, Illinois. PARTICIPANTS Each case patient included in this study had a KPC-negative rectal surveillance culture on admission followed by a KPC-positive surveillance culture later in the hospital stay. Each matched control patient had a KPC-negative rectal surveillance culture on admission and no KPC isolated during the hospital stay. RESULTS From June 2012 to June 2013, 2,575 patients were admitted to 4 LTACHs; 217 of 2,144 KPC-negative patients (10.1%) acquired KPC. In total, 100 of these patients were selected at random and matched to 100 controls by LTACH facility, admission date, and censored length of stay. Acquisitions occurred a median of 16.5 days after admission. On multivariate analysis, we found that exposure to higher colonization pressure (OR, 1.02; 95% CI, 1.01-1.04; P=.002), exposure to a carbapenem (OR, 2.25; 95% CI, 1.06-4.77; P=.04), and higher Charlson comorbidity index (OR, 1.14; 95% CI, 1.01-1.29; P=.04) were independent risk factors for KPC acquisition; the odds of KPC acquisition increased by 2% for each 1% increase in colonization pressure. CONCLUSIONS Higher colonization pressure, exposure to carbapenems, and a higher Charlson comorbidity index independently increased the odds of KPC acquisition among LTACH patients. Reducing colonization pressure (through separation of KPC-positive patients from KPC-negative patients using strict cohorts or private rooms) and reducing carbapenem exposure may prevent KPC cross transmission in this high-risk patient population. Infect Control Hosp Epidemiol 2017;38:670-677.

Evolution and Epidemiology of Multidrug-Resistant Klebsiella pneumoniae in the United Kingdom and Ireland

Klebsiella pneumoniae is a human commensal and opportunistic pathogen that has become a leading causative agent of hospital-based infections over the past few decades. The emergence and global expansion of hypervirulent and multidrug-resistant (MDR) clones of K. pneumoniae have been increasingly reported in community-acquired and nosocomial infections. Despite this, the population genomics and epidemiology of MDR K. pneumoniae at the national level are still poorly understood. To obtain insights into these, we analyzed a systematic large-scale collection of invasive MDR K. pneumoniae isolates from hospitals across the United Kingdom and Ireland. Using whole-genome phylogenetic analysis, we placed these in the context of previously sequenced K. pneumoniae populations from geographically diverse countries and identified their virulence and drug resistance determinants. Our results demonstrate that United Kingdom and Ireland MDR isolates are a highly diverse population drawn from across the global phylogenetic tree of K. pneumoniae and represent multiple recent international introductions that are mainly from Europe but in some cases from more distant countries. In addition, we identified novel genetic determinants underlying resistance to beta-lactams, gentamicin, ciprofloxacin, and tetracyclines, indicating that both increased virulence and resistance have emerged independently multiple times throughout the population. Our data show that MDR K. pneumoniae isolates in the United Kingdom and Ireland have multiple distinct origins and appear to be part of a globally circulating K. pneumoniae population.

Klebsiella pneumoniae is a major human pathogen that has been implicated in infections in healthcare settings over the past few decades. Antimicrobial treatment of K. pneumoniae infections has become increasingly difficult as a consequence of the emergence and spread of strains that are resistant to multiple antimicrobials. To better understand the spread of resistant K. pneumoniae, we studied the genomes of a large-scale population of extensively antimicrobial-resistant K. pneumoniae in the United Kingdom and Ireland by utilizing the fine resolution that whole-genome sequencing of pathogen genomes provides. Our results indicate that the K. pneumoniae population is highly diverse and that, in some cases, resistant strains appear to have spread across the country over a few years. In addition, we found evidence that some strains have acquired antimicrobial resistance genes independently, presumably in response to antimicrobial treatment.

Whole genome sequencing reveals high-resolution epidemiological links between clinical and environmental Klebsiella pneumoniae

Background

Klebsiella pneumoniae is a gram-negative bacterial species capable of occupying a broad range of environmental and clinical habitats. Known as an opportunistic pathogen, it has recently become a major causative agent of clinical infections worldwide. Despite growing knowledge about the highly diverse population of K. pneumoniae, the evolution and clinical significance of environmental K. pneumoniae, as well as the relationship between clinical and environmental K. pneumoniae, are poorly defined.

Methods

We isolated and sequenced K. pneumoniae from in-patients in a single hospital in Thailand, as well as hospital sewage, and surrounding canals and farms within a 20-km radius.

Results

Phylogenetic analysis of 77 K. pneumoniae (48 clinical and 29 non-clinical isolates) demonstrated that the two groups were intermixed throughout the tree and in some cases resided in the same clade, suggesting recent divergence from a common ancestor. Phylogenetic comparison of the 77 Thai genomes with 286 K. pneumoniae from a global collection showed that Thai isolates were closely related to the clinical sub-population of the global collection, indicating that Thai clinical isolates belonged to globally circulating lineages. Dating of four Thai K. pneumoniae clades indicated that they emerged between 50 and 150 years ago. Despite their phylogenetic relatedness, virulence factors and β-lactamase resistance genes were more numerous in clinical than in environmental isolates. Our results indicate that clinical and environmental K. pneumoniae are closely related, but that hospitals may select for isolates with a more resistant and virulent genotype.

Conclusions

These findings highlight the clinical relevance of environmental K. pneumoniae isolates.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-017-0397-1) contains supplementary material, which is available to authorized users.

Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP) in brain and spinal cord injury patients: potential for prolonged colonization

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To determine the prevalence of brain and spinal cord injury (BSCI) patients among all patients with Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP) and to evaluate clinical characteristics and duration of colonization.

SETTING

Tertiary care academic medical center.

METHODS

Electronic medical records of BSCI patients with KPC-KP from February 2009 to December 2014 were reviewed to determine clinical characteristics. Patients with multiple KPC-KPs were defined as those with isolates in different calendar months, and patients with a single positive isolate were compared with those with repeatedly positive isolates. Variables with a P-value of ⩽0.05 were considered statistically significant. Two archived isolates recovered from separate cultures of the same patient were compared with pulsed-field gel electrophoresis to calculate the duration of colonization.

RESULTS

Of the 218 patients with KPC-KP, 86 (39%) had BSCI and 27 (31%) had multiple KPC-KPs. The KPC-KPs from 20 (74%) patients with multiple isolates were available for analysis. Patients with repeated positive isolates were more likely to be younger (P=0.05), African American (P=0.05), suffer gunshot injuries (P=0.01) and other trauma (P=0.03) and have decubitus ulcers (P=0.05). Of the 20 patients with multiple isolates for analysis, 13 (65%) patients were colonized with the same strain type over time, and the strain persisted on average 373 days.

CONCLUSION

BSCI patients comprise a significant percentage of our KPC-KP population. Owing to repeated hospitalizations and prolonged colonization, they represent a substantial reservoir for these multidrug-resistant pathogens.