Containment of an outbreak of KPC-3-producing Klebsiella pneumoniae in Italy

Epidemicity and clonal replacement of hypervirulent carbapenem-resistant Klebsiella pneumoniae with diverse pathotypes and resistance profiles in a hospital

OBJECTIVES

The emergence of carbapenem-resistant and hypervirulent Klebsiella pneumoniae (CR-hvKP) poses a great threat to public health. There is a paramount need to increase awareness of the epidemiology, evolution, and pathogenesis of CR-hvKP.

METHODS

We collected strains of K. pneumoniae for over two years in a hospital. CR-hvKP strains were screened by polymerase chain reaction (PCR) with primers targeting the virulence genes. Genome sequencing was used to determine phylogenetic relationships and genetic characterization of virulence elements. The population dynamics within these strains were analyzed through epidemiological data. The string test, siderophore secretion, and murine infection experiments were performed to investigate virulence potential of different clones.

RESULTS

A total of 1172 K. pneumoniae strains were isolated from 817 patients, and 125 isolates were identified as CR-hvKP. In all, 102 CR-hvKP strains belonged to sequence type (ST) 11. Genomic analysis demonstrated that three clones of ST11 successively replaced each other in the hospital. Among them, the strains of clade A and clade B acquired virulence plasmids and the strains of clade C acquired a new integrating conjugative element (ICE). Phenotypic experiments revealed enhanced virulence potential of the recent epidemic clone from clade B. Sequence type 11 strains were favorable hosts for the convergence of virulence and resistance, indicated by clonal replacement and acquisition patterns of virulence elements.

CONCLUSION

The emergence of the enhanced virulence potential of ST11 CR-hvKP suggests that coevolution between hosts and exogenous factors can produce super-virulent CR-hvKP strains, highlighting the need to closely monitor changes in the virulence characteristics of CR-hvKP.

Outbreak of KPC-producing Klebsiella pneumoniae at a Portuguese university hospital: Epidemiological characterization and containment measures

Background

KPC-producing K pneumoniae (KPC-Kp) is a public health problem with important clinical and epidemiological implications. We describe an outbreak of KPC-Kp at vascular surgery and neurosurgery wards in a central hospital in Porto, Portugal.

Methods

A case of KPC-Kp was considered to be a patient positive for KPC-Kp with strong epidemiological plausibility of having acquired this microorganism in the affected wards and/or with genetic relationship ≥92% between KPC-Kp isolates. Active surveillance cultures (ASCs) and real-time polymerase chain reaction were used for the detection of carbapenemase genes through rectal swab in a selected population. Molecular analysis was performed using pulsed-field gel electrophoresis at the National Reference Laboratory. Patient risk factors were collected from the electronic medical record system. Information regarding outbreak containment strategy was collected from the Infection Control Unit records.

Results

Of the 16 cases, 11 (69%) were identified through active screening, representing 1.4% of the total 766 ASCs collected. The most frequent risk factors identified were previous admission (63%), antibiotic exposure in the past 6 months (50%), and immunodepression (44%). The length of stay until KPC-Kp detection was high (0-121 days, mean 35.6), as was the total length of stay (5-173 days, mean 56.6). Three patients (19%) were infected by KPC-Kp, 2 of whom died. One previously colonized patient died later because of KPC-Kp infection.

Conclusions

Multifactorial strategy based on contact precautions (with patient and healthcare professional cohorts) and ASC, as well as Antibiotic Stewardship Program reinforcement, allowed to contain this KPC-Kp outbreak.

Economic impact of an outbreak of carbapenemase producing-Enterobacteriaceae in a surgical intensive care unit

BACKGROUND

A 15-month outbreak of carbapenemase-producing Enterobacterales (CPE) occurred in the surgical intensive care unit (SICU) of our institution. We aimed to estimate the financial impact of this outbreak from the perspective of the French public health insurance system.

METHODS

The characteristics of the colonised/infected CPE patients and outbreak management according to French national guidelines were prospectively collected. Loss of productivity was assessed in terms of the reduction in total number of admissions (TNA) and discharges and in ICU length of stay (LoS). The additional financial burden associated with this outbreak was estimated by the accounting department of the hospital, including the impact of the extended LoS and restricted admissions.

RESULTS

Sixteen CPE patients (19 stays) were hospitalised in the SICU (10/2016-01/2018). The median ICU LoS for the CPE cases was 17 [8-36] days versus 6.5 and 6.1 days in 2016 and 2017, respectively, for the whole SICU population. The total number of lost bed days during the outbreak was 452. The TNA dropped dramatically in 2017 (decrease of 20.6%). The estimated costs were 768,386 EUR for bed days lost; 297,176 EUR and 63,675 EUR for the extended LoS for the CPE cases and the patients on contact precautions, respectively; 34,045 EUR for staff reinforcements; 85,764 EUR for bacteriological screening tests; and 42,857 EUR for antimicrobial treatment. The total financial burden of the outbreak was 1,291,903 EUR.

CONCLUSION

Management of a CPE outbreak in the SICU is associated with a huge financial burden for the unit and for the institution.

Necrotizing fasciitis of the vulva due to carbapenem-resistant Enterobacteriaceae as a complication of acute myeloid leukemia treatment: a case report

Background

Carbapenem-resistant Enterobacteriaceae strains have been reported in healthcare facilities with a rising incidence and are a major concern owing to infections that are often severe and can be potentially fatal, with limited therapeutic options. Klebsiella pneumonia represents the most frequently isolated microorganism.

Case presentation

We report the case of a Caucasian 52-year old Caucasian woman with acute myeloid leukemia was admitted to the inpatient hematology unit at a university referral hospital in Portugal. This hospital has endemic colonization of Carbapenem-resistant Enterobacteriaceae and contention measures are being implemented to reduce spreading of these multidrug resistant bacteria. After receiving first line chemotherapy according to the intermediate-dose cytarabine regimen, in context of deep medullary aplasia, the patient developed a localized infection of the vulva, which progressed to a necrotizing fasciitis. This is a rare, life-threatening, and fulminant infection. Carbapenem-resistant Klebsiella was isolated in both vulvar exudate and blood cultures. The patient underwent multiple schemes of antimicrobials, but progressed with multiorgan compromise and was admitted to the intensive care unit for a short period for stabilization. Surgical debridement was performed twice with clinical improvement and, after 6 weeks, a skin graft was executed with good response. Reevaluation of the hematologic disease showed a complete response to first cycle of induction therapy. Despite success in resolving this complex infection, decisions regarding antibiotic treatment represented a tremendous challenge for the whole team. The importance of multidisciplinary collaboration was key for the patient’s recovery and survival, and therefore, needs to be acknowledged.

Conclusions

This clinical case raises awareness on a clinical entity that can be life threatening and, therefore, requires a high level of suspicion to assure an early integrated approach to avoid complications. Endemic spreading of carbapenem-resistant Enterobacteriaceae is becoming a reality, and health policies need to be urgently undertaken at the national level to decrease morbidity and mortality because of health facilities-related infections.

Preventing infections caused by carbapenemase-producing bacteria in the intensive care unit - Think about the sink

OBJECTIVE

Outbreaks caused by carbapenemase-producing bacteria (CPB) are challenging to manage in critical care settings and can be protracted due to inadvertent and ubiquitous ecological niches within the built unit environment, such as handwashing sinks. We discuss evidence from a narrative review on transmission pathways and interventions for critical care practitioners.

METHODS

A literature review was undertaken using Pubmed, CINAHL and Embase and included outbreaks of CPB, and equivalent bacteria in critical care units, between 1998 and May 2020. Intervention studies targeting elements of sinks that were employed in response to outbreaks in critical care units were included (n = 30).

FINDINGS

We found control measures included sink removal, use of physical barriers or design modification to protect patients from sinks, engineering controls to mitigate bacterial dispersal and administrative controls. A multi-disciplinary approach involving practitioners from critical care, infection prevention and control, engineering and other staff, should be involved in ongoing measures and in outbreak control activities. Ascertaining the optimal method to end CPB outbreaks in critical care is challenging due to the lack of prospective studies available. However, the literature suggests that sinks can and do serve as reservoirs of CPB near critically ill patients, and should be considered hazardous, especially when sub-optimally designed or used.

Trends of major antimicrobial resistance phenotypes in enterobacterales and gram-negative non-fermenters from ATLAS and EARS-net surveillance systems: Italian vs. European and global data, 2008-2018

Antimicrobial resistance (AMR) is a growing health concern over the recent years. High AMR levels have been reported in Italy among European countries. Here, we analyze longitudinally the AMR trends observed in Italy for Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Enterobacter cloacae and Pseudomonas aeruginosa from the Antimicrobial Testing Leadership and Surveillance database, in comparison with data from the European Antimicrobial Resistance Surveillance Network (2008-2018). We also compare these longitudinal data from Italy with those from Europe and globally. Data analysis revealed highest resistance rates for carbapenems and difficult-to-treat resistance in A. baumannii (82.4% and 83.6%, respectively) followed by third-generation cephalosporin-resistant K. pneumoniae in Italy (≥50%). Resistance rates in Italy were higher compared to Europe and globally, as observed in both Antimicrobial Testing Leadership and Surveillance and European Antimicrobial Resistance Surveillance Network. These findings further substantiate the high AMR rates in Italy and aim to support informed decision making at a national level.

A systematic review of the effectiveness of cohorting to reduce transmission of healthcare-associated C. difficile and multidrug-resistant organisms

BACKGROUND

Cohorting of patients and staff is a control strategy often used to prevent the spread of infection in healthcare institutions. However, a comprehensive evaluation of cohorting as a prevention approach is lacking.

METHODS

We performed a systematic review of studies that used cohorting as part of an infection control strategy to reduce hospital-acquired infections. We included studies published between 1966 and November 30, 2019, on adult populations hospitalized in acute-care hospitals.

RESULTS

In total, 87 studies met inclusion criteria. Study types were quasi-experimental "before and after" (n = 35), retrospective (n = 49), and prospective (n = 3). Case-control analysis was performed in 7 studies. Cohorting was performed with other infection control strategies in the setting of methicillin-resistant Staphylococcus aureus (MRSA, n = 22), Clostridioides difficile infection (CDI, n = 6), vancomycin-resistant Enterococcus (VRE, n = 17), carbapenem-resistant Enterobacteriaceae infections (CRE, n = 22), A. baumannii (n = 15), and other gram-negative infections (n = 5). Cohorting was performed either simultaneously (56 of 87, 64.4%) or in phases (31 of 87, 35.6%) to help contain transmission. In 60 studies, both patients and staff were cohorted. Most studies (77 of 87, 88.5%) showed a decline in infection or colonization rates after a multifaceted approach that included cohorting as part of the intervention bundle. Hand hygiene compliance improved in approximately half of the studies (8 of 15) during the respective intervention.

CONCLUSION

Cohorting of staff, patients, or both is a frequently used and reasonable component of an enhanced infection control strategy. However, determining the effectiveness of cohorting as a strategy to reduce transmission of MDRO and C. difficile infections is difficult, particularly in endemic situations.

Antimicrobial stewardship and infection prevention interventions targeting healthcare-associated Clostridioides difficile and carbapenem-resistant Klebsiella pneumoniae infections: a scoping review

OBJECTIVES

This study assessed antimicrobial stewardship (AMS) and infection prevention (IP) interventions targeting healthcare-associated Clostridioides difficile and carbapenem-resistant Klebsiella pneumoniae (CRKP) infections, their key outcomes and the application of behaviour change principles in these interventions.

DESIGN

This scoping review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analysis Extension for Scoping Reviews (PRISMA-ScR) guidelines while focusing on acute healthcare settings in both low-to-middle income and high-income countries.

DATA SOURCES

The databases searched were MEDLINE, PubMed, Web of Science and CINAHL between 22 April 2020 and 30 September 2020.

ELIGIBILITY

The review included peer-reviewed articles published in English language between 2010 and 2019. Studies that focussed on IP and/or AMS interventions primarily targeting C. difficile or CRKP were included. Studies that assessed effectiveness of diagnostic devices or treatment options were excluded from this review.

DATA EXTRACTION AND SYNTHESIS

An abstraction sheet calibrated for this study was used to extract data on the main study characteristics including the population, intervention and outcomes of interest (antimicrobial use, compliance with IP interventions and risk for C. difficile and CRKP). A narrative synthesis of the results is provided.

RESULTS

The review included 34 studies. Analysis indicates that interventions targeting C. difficile and CRKP include Education, Surveillance/Screening, Consultations, Audits, Policies and Protocols, Environmental measures, Bundles, Isolation as well as Notifications or alerts (represented using the ESCAPE-BIN acronym). The identified outcomes include antimicrobial use, resistance rates, risk reduction, adherence to contact precautions, hospital stay and time savings. AMS and IP interventions tend to be more adhoc with limited application of behaviour change principles.

CONCLUSION

This scoping review identified the AMS and IP interventions targeting C. difficile and CRKP in healthcare settings and described their key outcomes. The application of behaviour change principles in AMS and IP interventions appears to be limited.

Development of a new spectrophotometric assay for rapid detection and differentiation of KPC, MBL and OXA-48 carbapenemase-producing Klebsiella pneumoniae clinical isolates

The increased prevalence of carbapenemase-producing Enterobacteriaceae (CPE) has made essential the design of quicker tests for CPE detection. In the present study, a simple and rapid assay was developed based on measurement of the hydrolytic activity of imipenem at a final concentration of 65 µg/mL (100 µM) through ultraviolet-visible (UV-Vis) spectrophotometry. All measurements were conducted at 297 nm. A total of 83 carbapenem-non-susceptible CPE, consisting of Klebsiella pneumoniae clinical isolates and genotypically characterised as KPC-, VIM-, NDM- or OXA-48-producers, were tested. For comparison, 30 carbapenem-non-susceptible clinical isolates, consisting of Escherichia coli and K. pneumoniae and genotypically confirmed as non-CPE, were also examined. The spectrophotometric assay enabled efficient discrimination of CPE from non-CPE isolates even in 45 min (P < 0.0001). Moreover, the presence of phenylboronic acid (PBA) or ethylene diamine tetra-acetic acid (EDTA) in the reaction mixture was able to inhibit the hydrolytic capacity of KPC- or metallo-β-lactamase (MBL)-producers, respectively, while the hydrolytic activity of OXA-48-producing strains was not affected by the presence of these inhibitors (P < 0.001). The newly developed assay presented 100% sensitivity and specificity to detect and differentiate KPC-, MBL- and OXA-48-producers compared with genotypic characterisation. Thus, the proposed spectrophotometric method can be considered as an easy, fast, accurate and cost-effective diagnostic tool for screening carbapenem-non-susceptible K. pneumoniae isolates in the clinical laboratory.

Emergence of NDM-1-producing Klebsiella pneumoniae in Greece: evidence of a widespread clonal outbreak

OBJECTIVES

NDM-producing Enterobacteriaceae clinical isolates remain uncommon in the European region. We describe the emergence and broad dissemination of one successful NDM-1-producing Klebsiella pneumoniae clone in Greek hospitals.

METHODS

During a 4 year survey (January 2013-December 2016), 480 single-patient carbapenem non-susceptible K. pneumoniae isolates, phenotypically MBL positive, were consecutively recovered in eight Greek hospitals from different locations and subjected to further investigation. Antimicrobial susceptibility testing, combined-disc test, identification of resistance genes by PCR and sequencing, molecular fingerprinting by PFGE, plasmid profiling, replicon typing, conjugation experiments and MLST were performed.

RESULTS

Molecular analysis confirmed the presence of the blaNDM-1 gene in 341 (71%) K. pneumoniae isolates. A substantially increasing trend of NDM-1-producing K. pneumoniae was noticed during the survey (R2 = 0.9724). Most blaNDM-1-carrying isolates contained blaCTX-M-15, blaOXA-1, blaOXA-2 and blaTEM-1 genes. PFGE analysis clustered NDM-1 producers into five distinct clonal types, with five distinct STs related to each PFGE clone. The predominant ST11 PFGE clonal type was detected in all eight participating hospitals, despite adherence to the national infection control programme; it was identical to that observed in the original NDM-1 outbreak in Greece in 2011, as well as in a less-extensive NDM-1 outbreak in Bulgaria in 2015. The remaining four ST clonal types (ST15, ST70, ST258 and ST1883) were sporadically detected. blaNDM-1 was located in IncFII-type plasmids in all five clonal types.

CONCLUSIONS

This study gives evidence of possibly the largest NDM-1-producing K. pneumoniae outbreak in Europe; it may also reinforce the hypothesis of an NDM-1 clone circulating in the Balkans.

Containing Carbapenemase-producing Klebsiella pneumoniae in an endemic setting

Background

Carbapenemase-producing K. pneumoniae (CP-Kp) has been established as important nosocomial pathogen in most tertiary care hospitals in Greece. The aim of the present study was to examine the impact of an enhanced infection control program on the containment of CP-Kp in a haematology unit where the incidence of CP-Kp infections was high.

Methods

The study was conducted from June 2011 to December 2014 in a haematology unit of a tertiary-care 500-bed hospital located in Athens, Greece. A bundled intervention (active surveillance cultures, separation of carriers from non-carriers, assignment of dedicated nursing staff, contact precautions, environmental cleaning, and promotion of hand hygiene) was tested whether would reduce colonization and infection caused by CP-Kp.

Results

A total of 2507 rectal swabs were obtained; 1199 upon admission from June 2011 to June 2013 and 1307 during hospitalization from June 2011 to December 2012. During intervention the admission prevalence of CP-Kp colonization (p < 0.001 for linear trend), the hospitalization prevalence (p = 0.001 for linear trend) and the incidence rate of CP-Kp colonization (p = 0.072 for linear trend) were declining. Application of segmented linear regression revealed that both the change in the level of CP-Kp BSI incidence rates (p = 0.001) as well as the difference between pre- and post-intervention slopes were statistically significant (p < 0.001).

Conclusions

A bundled intervention including active surveillance cultures on admission can attain maximum containment of CP-Kp colonization and infection in endemic acute healthcare settings.

A review on bacterial resistance to carbapenems: epidemiology, detection and treatment options

Carbapenems are a class of antimicrobial agents reserved for infections caused by multidrug-resistant microorganisms. The emergence of carbapenem resistance has become a serious public health threat. This type of antimicrobial resistance is spreading at an alarming rate, resulting in major outbreaks and treatment failure of community-acquired and nosocomial infections caused by the clinically relevant carbapenem-producing Enterobacteriaceae or carbapenem-resistant Enterobacteriaceae. This review is focused on carbapenem resistance, including mechanisms of resistance, history and epidemiology, phenotypic and genotypic detection in the clinically relevant bacterial pathogens and the possible treatment options available.

How Cities Cope in Outbreak Events?

An outbreak can cause more problems than just the spread of disease. It can be an antagonistic nemesis to our cities and communities, particularly if we lack preparedness and resilience. Its progress is usually unclear as it can be completely different from case to case, and can react differently in different contexts and with different groups of people. Such reactions may purely relate to climatic conditions, hygienic status, and environmental attributes of the context. Those reactions can also differ from one group of people to another, while the disease has to find its correct host as well the way it can transmit and evolve. Consequently, the magnitude of impacts would depend on many factors, of which the nature of the disease is very important during the whole outbreak progress.

Efficiency of different control measures for preventing carbapenemase-producing enterobacteria and glycopeptide-resistant Enterococcus faecium outbreaks: a 6-year prospective study in a French multihospital institution, January 2010 to December 2015

An infection control programme was implemented in a 21,000-bed multihospital institution for controlling the spread of carbapenemase-producing Enterobacteriaceae (CPE) and glycopeptide-resistant Enterococcus faecium (GRE), classified as ‘emergent extensively drug-resistant bacteria’ (eXDR) in France. We evaluated factors associated with outbreaks occurrence (n = 103), which followed 901 eXDR introductions (index case followed or not by secondary cases) from 2010 to 2015. In univariate analysis, knowing that patients had been hospitalised abroad, bacterial species (GRE vs CPE, as well as the CPE Klebsiella pneumoniae compared with the other Enterobacteriaceae species) and type of measures implemented within the first 2 days of hospitalisation were associated with outbreaks occurrence, but not the type of wards where carriers were hospitalised, nor the eXDR colonisation or infection status. In multivariate analysis, occurrence of outbreaks was significantly lower when contact precautions (odds ratio (OR): 0.34; 95% confidence interval (CI): 0.22–0.54) and even more when dedicated nursing staff (OR: 0.09; 95% CI: 0.02–0.39) were implemented around eXDR index cases within the first 2 days of hospitalisation (p < 10 ^− 3). GRE introductions were more frequently associated with occurrence of outbreaks than CPE (OR: 3.58; 95% CI: 2.32–5.51, p < 10 ^− 3). A sustained and coordinated strategy is efficient to limit the spread of eXDR at the scale of a large health institution.

The burden of colonization and infection by carbapenemase-producing Enterobacteriaceae in the neuro-rehabilitation setting: a prospective six-year experience

We describe the high burden of carbapenemase-producing Enterobacteriaceae (CPE) colonization and infection in a neuro-rehabilitation hospital in Italy over a 6-year period. Overall, 9.3% of patients were found to be CPE carriers on admission; the rates of CPE in-hospital acquisition and CPE-BSI were 9.2 and 2.9 cases per 10,000 patient days, respectively.

Diversity among blaKPC-containing plasmids in Escherichia coli and other bacterial species isolated from the same patients

Carbapenem resistant Enterobacteriaceae are a significant public health concern, and genes encoding the Klebsiella pneumoniae carbapenemase (KPC) have contributed to the global spread of carbapenem resistance. In the current study, we used whole-genome sequencing to investigate the diversity of blaKPC-containing plasmids and antimicrobial resistance mechanisms among 26 blaKPC-containing Escherichia coli, and 13 blaKPC-containing Enterobacter asburiae, Enterobacter hormaechei, K. pneumoniae, Klebsiella variicola, Klebsiella michiganensis, and Serratia marcescens strains, which were isolated from the same patients as the blaKPC-containing E. coli. A blaKPC-containing IncN and/or IncFIIK plasmid was identified in 77% (30/39) of the E. coli and other bacterial species analyzed. Complete genome sequencing and comparative analysis of a blaKPC-containing IncN plasmid from one of the E. coli strains demonstrated that this plasmid is present in the K. pneumoniae and S. marcescens strains from this patient, and is conserved among 13 of the E. coli and other bacterial species analyzed. Interestingly, while both IncFIIK and IncN plasmids were prevalent among the strains analyzed, the IncN plasmids were more often identified in multiple bacterial species from the same patients, demonstrating a contribution of this IncN plasmid to the inter-genera dissemination of the blaKPC genes between the E. coli and other bacterial species analyzed.

Whole genome sequence revealed the fine transmission map of carbapenem-resistant Klebsiella pneumonia isolates within a nosocomial outbreak

Background

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a major cause of nosocomial infections worldwide. The transmission route of CRKP isolates within an outbreak is rarely described. This study aimed to reveal the molecular characteristics and transmission route of CRKP isolates within an outbreak of nosocomial infection.

Methods

Collecting case information, active screening and targeted environmental monitoring were carried out. The antibiotic susceptibility, drug-resistant genes, molecular subtype and whole genome sequence of CRKP strains were analyzed.

Results

Between October and December 2011, 26 CRKP isolates were collected from eight patients in a surgical intensive care unit and subsequent transfer wards of Beijing Tongren hospital, China. All 26 isolates harbored bla_KPC-2, bla_SHV-1, and bla_CTX-M-15 genes, had the same or similar pulsed-field gel electrophoresis patterns, and belonged to the sequence type 11 (ST11) clone. By comprehensive consideration of genomic and epidemiological information, a putative transmission map was constructed, including identifying one case as an independent event distinct from the other seven cases, and revealing two transmissions starting from the same case.

Conclusions

This study provided the first report confirming an outbreak caused by K. pneumoniae ST11 clone co-harboring the bla_KPC-2, bla_CTX-M-15, and bla_SHV-1 genes, and suggested that comprehensive consideration of genomic and epidemiological data can yield a fine transmission map of an outbreak and facilitate the control of nosocomial transmission.

Clinically Relevant Plasmid-Host Interactions Indicate that Transcriptional and Not Genomic Modifications Ameliorate Fitness Costs of Klebsiella pneumoniae Carbapenemase-Carrying Plasmids

The rapid dissemination of antimicrobial resistance (AMR) around the globe is largely due to mobile genetic elements, such as plasmids. They confer resistance to critically important drugs, including extended-spectrum beta-lactams, carbapenems, and colistin. Large, complex resistance plasmids have evolved alongside their host bacteria. However, much of the research on plasmid-host evolution has focused on small, simple laboratory plasmids in laboratory-adapted bacterial hosts. These and other studies have documented mutations in both host and plasmid genes which occur after plasmid introduction to ameliorate fitness costs of plasmid carriage. We describe here the impact of two naturally occurring variants of a large AMR plasmid (pKpQIL) on a globally successful pathogen. In our study, after pKpQIL plasmid introduction, no changes in coding domain sequences were observed in their natural host, Klebsiella pneumoniae However, significant changes in chromosomal and plasmid gene expression may have allowed the bacterium to adapt to the acquisition of the AMR plasmid. We hypothesize that this was sufficient to ameliorate the associated fitness costs of plasmid carriage, as pKpQIL plasmids were maintained without selection pressure. The dogma that removal of selection pressure (e.g., antimicrobial exposure) results in plasmid loss due to bacterial fitness costs is not true for all plasmid/host combinations. We also show that pKpQIL impacted the ability of K. pneumoniae to form a biofilm, an important aspect of virulence. This study used highly relevant models to study the interaction between AMR plasmids and pathogens and revealed striking differences from results of studies done on laboratory-adapted plasmids and strains.IMPORTANCE Antimicrobial resistance is a serious problem facing society. Many of the genes that confer resistance can be shared between bacteria through mobile genetic elements, such as plasmids. Our work shows that when two clinically relevant AMR plasmids enter their natural host bacteria, there are changes in gene expression, rather than changes to gene coding sequences. These changes in gene expression ameliorate the potential fitness costs of carriage of these AMR plasmids. In line with this, the plasmids were stable within their natural host and were not lost in the absence of selective pressure. We also show that better understanding of the impact of resistance plasmids on fundamental pathogen biology, including biofilm formation, is crucial for fighting drug-resistant infections.

Mortality due to KPC carbapenemase-producing Klebsiella pneumoniae infections: Systematic review and meta-analysis: Mortality due to KPC Klebsiella pneumoniae infections

INTRODUCTION

KPC carbapenemase-producing Klebsiella pneumoniae (KPC-KP) has become a major public health challenge. Accordingly, this study sought to use a systematic review of the scientific literature to ascertain the mortality of KPC-KP infection, and analyze such mortality by country, year of publication, hospital ward, and type of interpretation used to define carbapenem resistance.

METHODOLOGY

A search without language restrictions was made of the MEDLINE, CENTRAL, EBSCO, LILACS and EMBASE databases from 1996 through June 2017, to locate all studies which had determined the existence of KPC-KP infection. We then performed a meta-analysis of all studies that reported KPC-KP infection-related mortality, and analyzed mortality by subgroup in accordance with standard methodology.

RESULTS

A total of 51 papers were included in the systematic review. From 2005 through 2017, data on KPC-KP infection were reported in 5124 patients, with an average of 465 patients per year. The most widely studied type of infection was bacteremia (28∙0%). The meta-analysis showed that overall mortality for the 37 studies was 41.0% (95%CI 37.0-44.0), with the highest mortality rates being observed in oncology patients, 56.0% (95%CI 38.1-73.0), and Brazil, 51.3% (95%CI 43.0-60.0).

CONCLUSION

KPC-KP infection-related mortality is high, is manifested differently in some countries, and is highest among oncology patients.

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.

NDM-1 Hazard in the Balkan States: Evidence of the First Outbreak of NDM-1-Producing Klebsiella pneumoniae in Bulgaria

New Delhi MBL (NDM) carbapenemase-producing Klebsiella pneumoniae has become one of the most concerning multidrug-resistant pathogens. The Balkan counties are considered a reservoir for the spread of such strains based on several reports documenting NDM infections after hospitalization in this region. Nevertheless, NDM-producing K. pneumoniae have been only occasionally documented from Balkans. The current study documents the first polyclonal outbreak caused by NDM-1-producing K. pneumoniae in Bulgaria. From July 2015 to April 2016, all 25 single-patient carbapenem-nonsusceptible K. pneumoniae isolates were collected. Phenotypic and molecular screening revealed that 17 produced NDM-1 carbapenemase. All NDM-1 producers harbored bla_CTX-M-15, bla_CMY-4, bla_TEM-1, and bla_OXA-2; five also harbored bla_OXA-1. In all cases, bla_NDM-1 was flanked upstream by ISAba125 element and downstream by ble_MBL. Pulsed-field gel electrophoresis (PFGE) clustered NDM-1-positive isolates into four distinct clonal types, A to D. MLST assigned isolates of the dominant clonal type A (n = 14) to sequence type (ST) 11, while isolates of clonal types B, C, and D to ST16, ST15, and ST391, respectively. Of interest, ST11 isolates belonged to the same PFGE type as those of the recently described NDM-1 ST11 clonal outbreak in Greece. Traveling abroad or overseas hospitalization was not reported in any case, suggesting most likely intra- and interhospital dissemination. The study presents the first polyclonal outbreak of NDM-producing K. pneumoniae in the Balkans and underlines the need for larger epidemiological studies in the region to illustrate commonalities in the transmission of NDM clones and possible sources in the community.

Successful containment of the first KPC-producing Klebsiella pneumoniae outbreak in Croatia

AIM

We report the first outbreak caused by Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae sequence type 258 (ST 258) clone that occurred in Croatia from May to December 2012.

MATERIALS & METHODS

23 carbapenem-resistant K. pneumoniae isolates were recovered from clinical and screening specimens of 12 patients hospitalized in a regional hospital. The first isolates from the 12 patients were typed using pulsed-field gel electrophoresis and multilocus sequence typing.

RESULTS

PCR detection showed that all isolates harbored the bla _KPC-2 gene, together with bla _TEM-116 and bla _SHV-11.

CONCLUSION

The rapid detection of KPC-producing K. pneumoniae and vigorous implementation of infection control measures were necessary to successfully control the outbreak.

The association between infection control interventions and carbapenem-resistant Enterobacteriaceae incidence in an endemic hospital

BACKGROUND

Israel experienced a national outbreak of carbapenem-resistant Enterobacteriaceae (CRE) starting in 2006.

AIM

To assess the association between infection control (IC) interventions implemented in a referral hospital in Israel and CRE incidence.

METHODS

Retrospective quasi-experimental study of prospectively collected data. CRE incidence, defined as the number of patients newly acquiring CRE in surveillance or clinical samples per 100,000 hospital-days, was plotted quarterly between 2005 and 2016. IC interventions were applied at different time-points throughout this period. Data were collected on IC staffing, number of rectal surveillance cultures, and carbapenem consumption. Autocorrelated segmented linear regression analysis was used to assess the time-points at which a significant change in the CRE incidence trend occurred, and the association between the timing of IC intervention implementation and observed CRE trends was assessed. Trends between time-points were expressed as quarterly percent change (QPC) with 95% confidence intervals (CIs).

FINDINGS

Between 2005 and 2008, CRE incidence increased significantly (QPC: 19.7%; CI: 11.5-28.4), reaching a peak of 186.6 new acquisitions per 100,000 hospital-days. From mid-2011 until the end of follow-up, there was a significantly decreasing incidence trend (QPC: -4.5; CI: -6.4 to -2.5). Cohorting of patients, screening of contacts and high-risk patients on admission were insufficient to control the epidemic. Improved hand hygiene compliance, cohorting with dedicated nursing staff, addition of regular screening in high-risk departments, and carbapenem restriction were required. Decreasing CRE incidence was observed with an infectious diseases/IC staffing of 1.2-1.5 per 100 beds and 20,000-36,000 yearly CRE surveillance samples.

CONCLUSION

A multi-faceted hospital-wide intervention programme is required to control CRE in hospital settings.

Carbapenem-Resistant Klebsiella pneumoniae: Results of a Laboratory Surveillance Program in an Italian General Hospital (August 2014-January 2015) : Surveillance of Carbapenem-resistant Klebsiella pneumoniae

In this study we report the analysis of 131 Klebsiella pneumoniae (K. pneumoniae) clinical isolates from patients hospitalized in various wards, of Perugia General Hospital, from August 2014 to January 2015. Forty two isolates (32.1 %), were resistant to at least one carbapenem antibiotic and, among these isolates, 14 (33.3 %) exhibited resistance to colistin. All isolates were carbapenemases producers and 41 (97.6 %) harboured the bla KPC gene. Carbapenem-resistant K. pneumoniae isolates (CRKPs) were, also, typed for the genotypic diversity and the results revealed the circulation of two major clusters.This surveillance study evidences the spread of CRKP isolates in Perugia General Hospital and confirms that carbapenem-resistant K. pneumoniae isolates have reached epidemic dissemination in Italy. In addition the percentage of resistance to colistin resulted to be less than that observed in other hospital laboratories across Italy. In conclusion the circulation of these isolates should be monitored and appropriate policy of surveillance must be used, in a target manner, in order to reduce the spread of carbapenem-resistant isolates.

Long-term outbreak of Klebsiella pneumoniae& third generation cephalosporin use in a neonatal intensive care unit in north India

BACKGROUND & OBJECTIVES

The indiscriminate use of third generation cephalosporin has contributed to the emergence and widespread dissemination of extended spectrum β lactamases (ESBL) genes in Klebsiella pneumoniae. This study was undertaken to elaborate the genetic behaviour of ESBL - producing K. pneumoniae isolates in the neonatal intensive care unit (NICU) of a tertiary care hospital in north India causing successive outbreaks in context with empirical third generation cephalosporin use.

METHODS

Isolates of K. pneumoniae (43 from blood, 3 from pus and endotracheal tube, 4 from environment) causing successive outbreaks in the NICU of a tertiary care university hospital were studied for two years. Antimicrobial susceptibility testing was done by disc diffusion and minimum inhibitory concentration (MIC) determination by agar dilution methods. ESBL production was determined by phenotypic and genotypic methods. Clonal relatedness among the isolates was studied by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). Genetic environment of these isolates was assessed by the presence of integrons and gene cassettes. Transformation experiments were done, and plasmids of these isolates were characterized by stability testing and incompatibility testing. Subsequently, a change in the ongoing antibiotic policy was adopted, and corresponding changes in the behaviour of these isolates studied.

RESULTS

During the period from August 2011 to January 2013, 46 isolates of monoclonal ESBL K. pneumoniae were obtained from different neonates and four similar environmental isolates were studied. Multidrug-resistant ESBL isolates harboured both blaCTXM-15 and bla SHV-5. The dfr and aac-6 ' resistant genes were found in gene cassettes. A 50 kb plasmid belonging to IncFIIA group was detected in all the isolates which was transferable and stable. The emergence and regression of the outbreaks coincided with antibiotic usage in the NICU, with widespread empirical use of cefotaxime being responsible for their persistence in the environment.

INTERPRETATION & CONCLUSIONS

The study indicates that empirical use of third generation cephalosporins may promote the emergence, persistence, and dissemination of resistant isolates in the hospital environment. Periodic review of antibiotic policy is necessary for rationalized use of antibiotics.

Outbreak of Klebsiella pneumoniae carbapenemase-producing K pneumoniae: A systematic review

BACKGROUND

First detected in the United States in 1996, Klebsiella pneumoniae carbapenemase (KPC) has spread internationally among gram-negative bacteria, especially K pneumoniae. These microorganisms can cause serious infections in hospitalized patients, and there are few therapeutic options, culminating in increased mortality. The objective of this study was to describe the occurrence of outbreaks that were caused by KPC-producing K pneumoniae, emphasizing the interventions that were implemented to contain the outbreaks.

METHODS

PubMed, Web of Knowledge, and Literatura Latino Americana em Ciências da Saúde databases were searched for articles that were published between 2001 and 2012 according to the recommendations of Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

Of the 586 studies identified, 13 were selected for the final sample. Most studies showed that the containment of KPC outbreaks is possible in hospital settings through several actions, particularly use of surveillance cultures and the establishment of contact precautions.

CONCLUSIONS

The results show that limiting the cross-transmission of these and other KPC-producing bacteria is possible in a hospital setting. However, such isolates need to be detected early with the aid of culture surveillance and contained early using appropriate actions immediately to prevent an outbreak.

Control of carbapenemase-producing Enterobacteriaceae outbreaks in acute settings: an evidence review

BACKGROUND

In recent years, infections with carbapenemase-producing Enterobacteriaceae (CPE) have been increasing globally and present a major public health challenge.

AIM

To review the international literature: (i) to describe CPE outbreaks in acute hospital settings globally; and (ii) to identify the control measures used during these outbreaks and report on their effectiveness.

METHODS

A systematic search of MEDLINE and EMBASE databases, abstract lists for key conferences and reference lists of key reviews was undertaken, and information on unpublished outbreaks was sought for 2000-2015. Where relevant, risk of bias was assessed using the Newcastle-Ottawa scale. A narrative synthesis of the evidence was conducted.

FINDINGS

Ninety-eight outbreaks were eligible. These occurred worldwide, with 53 reports from Europe. The number of cases (CPE infection or colonization) involved in outbreaks varied widely, from two to 803. In the vast majority of outbreaks, multi-component infection control measures were used, commonly including: patient screening; contact precautions (e.g. gowns, gloves); handwashing interventions; staff education or monitoring; enhanced environmental cleaning/decontamination; cohorting of patients and/or staff; and patient isolation. Seven studies were identified as providing the best-available evidence on the effectiveness of control measures. These demonstrated that CPE outbreaks can be controlled successfully using a range of appropriate, commonly used, infection control measures. However, risk of bias was considered relatively high for these studies.

CONCLUSION

The findings indicate that CPE outbreaks can be controlled using combinations of existing measures. However, the quality of the evidence base is weak and further high-quality research is needed, particularly on the effectiveness of individual infection control measures.

Epidemic potential of Escherichia coli ST131 and Klebsiella pneumoniae ST258: a systematic review and meta-analysis

OBJECTIVES

Observational studies have suggested that Escherichia coli sequence type (ST) 131 and Klebsiella pneumoniae ST258 have hyperendemic properties. This would be obvious from continuously high incidence and/or prevalence of carriage or infection with these bacteria in specific patient populations. Hyperendemicity could result from increased transmissibility, longer duration of infectiousness, and/or higher pathogenic potential as compared with other lineages of the same species. The aim of our research is to quantitatively estimate these critical parameters for E. coli ST131 and K. pneumoniae ST258, in order to investigate whether E. coli ST131 and K. pneumoniae ST258 are truly hyperendemic clones.

PRIMARY OUTCOME MEASURES

A systematic literature search was performed to assess the evidence of transmissibility, duration of infectiousness, and pathogenicity for E. coli ST131 and K. pneumoniae ST258. Meta-regression was performed to quantify these characteristics.

RESULTS

The systematic literature search yielded 639 articles, of which 19 data sources provided information on transmissibility (E. coli ST131 n=9; K. pneumoniae ST258 n=10)), 2 on duration of infectiousness (E. coli ST131 n=2), and 324 on pathogenicity (E. coli ST131 n=285; K. pneumoniae ST258 n=39). Available data on duration of carriage and on transmissibility were insufficient for quantitative assessment. In multivariable meta-regression E. coli isolates causing infection were associated with ST131, compared to isolates only causing colonisation, suggesting that E. coli ST131 can be considered more pathogenic than non-ST131 isolates. Date of isolation, location and resistance mechanism also influenced the prevalence of ST131. E. coli ST131 was 3.2 (95% CI 2.0 to 5.0) times more pathogenic than non-ST131. For K. pneumoniae ST258 there were not enough data for meta-regression assessing the influence of colonisation versus infection on ST258 prevalence.

CONCLUSIONS

With the currently available data, it cannot be confirmed nor rejected, that E. coli ST131 or K. pneumoniae ST258 are hyperendemic clones.

Antibiotic trends of Klebsiella pneumoniae and Acinetobacter baumannii resistance indicators in an intensive care unit of Southern Italy, 2008-2013

Background

The overuse of antimicrobials is one of the main factors responsible for the development and spread of antimicrobial resistance, together with other causes, such as intra- and inter-hospital spread of resistant microorganisms and infection control policies and practices. The objective of the present study is to report the trends of Klebsiella pneumoniae and Acinetobacter baumannii antimicrobial resistance indicators in an Italian intensive care unit (ICU) during a six-year period, from 2008 to 2013.

Methods

Susceptibility data and annual antibiotic consumptions in the ICU were retrospectively obtained from the clinical laboratory and the pharmacy. Trends over time of resistance rates (RRs) and of incidence densities of resistant isolates were determined by linear regression.

Results

Isolation density of A. baumannii increased significantly from 2008 (20.4 per 1,000 patient-days) to 2013 (58.1 per 1,000 patient-days) and of K. pneumoniae from 2010 (22.3 per 1,000 patient-days) to 2013 (55.9 per 1,000 patient-days). RRs of third-generation cephalosporins (3GCs)-resistant K. pneumoniae (from 2010: 41.9 %, to 2012: 87.0 %), of carbapenem-resistant K. pneumoniae (from 2008: 0 %, to 2013: 59.2 %), and of carbapenem-resistant A. baumannii (from 2008: 87.5 %, to 2013: 96.6 %) showed significant increasing trends. Carbapenems was the main antibiotic class consumed (24.9 % of the total antimicrobial usage density), followed by 3GCs (21.0 %), fluoroquinolones (20.6 %), aminoglycosides (17.3 %), penicillins (15.1 %) and glycopeptides (1.1 %). Carbapenems consumption decreased from 2008 to 2012 and then increased in 2013. Glycopeptides consumption decreased from 2008 to 2011 and then increased in 2013. Aminoglycosides consumption decreased from 2008 to 2010 and increased from 2012 to 2013. Finally, 3GC, penicillins and fluoroquinolones consumptions decreased from 2012 to 2013.

Conclusions

RRs of carbapenem-resistant A. baumannii and of carbapenem- and 3GC-resistant K. pneumoniae were higher than those for Europe. Our findings highlight the necessity to implement an integrated system for monitoring not only consumption of antibiotics and resistance profiles but also the clonality of alert microorganisms in the ICU for effective infection control.

Diffusion and transmission of carbapenem-resistant Klebsiella pneumoniae in the medical and surgical wards of a university hospital in Milan, Italy

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is emerging as a public health problem worldwide. In Italy, a remarkable increase in CRKP cases has been reported since 2010. In this study, CRKP diffusion, distribution and in-hospital transmission trends were evaluated in a university hospital in Milan, Italy, from January 2012 to December 2013. Isolates from 63 newly detected CRKP-positive patients were genotyped, and possible transmission was determined by combining the molecular results with data concerning the patients' admission and in-hospital transfers. Most of the cases (90.4%) were from general medical and surgery wards, and the remaining 9.6% were from the intensive care unit. Fifteen of the 46 hospital-associated cases (32.6%) were attributable to in-hospital transmission. After the introduction of targeted and hospital-wide control measures, the transmission index significantly decreased from 0.65 to 0.13 (p=0.01). There was also a decrease in the overall nosocomial case incidence, from 0.37 to 0.17 per 1000 person-days (p=0.07). Our findings indicate that the spread of CRKP in Northern Italy hospitals may go far beyond high-risk settings (i.e., intensive care units) and that strict surveillance should be extended to general areas of care.

Control of emerging extensively drug-resistant organisms (eXDRO) in France: a survey among infection preventionists from 286 healthcare facilities

We performed a multicenter survey in May-June 2012 to assess strategies in preventing the spread of emerging extensively drug-resistant organisms (eXDRO), including glycopeptide-resistant enterococci and carbapenemase-producing Enterobacteriaceae, in a convenient sample of French healthcare facilities (HCFs). The collected data included organization and measures to: (1) identify patients at risk for carrying eXDRO, (2) investigate and control sporadic cases or outbreaks, and (3) describe prior 2010-2012 episodes with one or more colonized patients. Of the 286 participating HCFs, 163 (57 %) and 134 (47 %) reported having a specific procedure to detect repatriates or patients hospitalized in foreign countries within the last year, respectively. Among the 97 HCFs with prior at-risk patient management experience, contact precautions, hospitalization in a single room, and screening for eXDRO carriage were quasi-systematically performed (n = 92/97, 95 %). The alleged time between admission and alert ranged from 24 to 48 h after the patient's admission; 203 (71 %) HCFs recommended obtaining three successive negative screening samples to declare a patient free of eXDRO colonization. During the last two years, 64 HCFs (23 %) had to manage at least one eXDRO case, with a total of 20 outbreaks with more than one secondary case. This first national survey shows that French HCFs were not totally ready to control eXDRO spread in 2012. Their previous experiences and capacities in controlling eXDRO outbreaks are quite heterogeneous from one hospital to another. Further researches are needed in order to understand the constraints in applying national guidance.

French recommendations for the prevention of 'emerging extensively drug-resistant bacteria' (eXDR) cross-transmission

Controlling the spread of multi- or extensively drug-resistant bacteria (MDR or XDR) includes a dual strategy for reducing antibiotic prescriptions and preventing their spread from patient carriers. Standard precautions are applicable to all health professionals caring for any patients; additional barrier precautions (isolation) are recommended for patients carrying transmissible infectious diseases or MDR bacteria in sporadic or epidemic situations. Moreover, additional precautions may be required for populations at particular risk of infection or colonization by emerging XDR (eXDR), defined in our country as carbapenemase-producing Enterobacteriaceae and vancomycin-resistant enterococci. Our ability to detect and identify eXDR carriers early and ensure their follow-up, through effective communication between all those involved, is a significant challenge for controlling their spread. Thus, the French High Committee for Public Health has updated and standardized all French existing recommendations concerning the prevention of the cross-transmission of these bacteria, and these recommendations are summarized in this review. The recommendations are based on scientific and operational knowledge up to 2013. Different preventive strategies are recommended for patients found to be carrying eXDR and those who are considered to be at risk of having eXDR because of a history of contact. The local context, the experience of the infection control team, the different times at which detection of eXDR takes place (during admission, hospitalization, etc.) and the epidemiological situation (sporadic cases, clusters, outbreaks, widespread epidemic) must be included in risk assessments that in turn inform the control measures that should be applied in each clinical circumstance.

Deaths attributable to carbapenem-resistant Enterobacteriaceae infections

In 7 studies, rates ranged from 26% to 44%; in 2 studies, rates were −3% and −4%, respectively.

We evaluated the number of deaths attributable to carbapenem-resistant Enterobacteriaceae by using studies from around the world published before April 9, 2012. Attributable death was defined as the difference in all-cause deaths between patients with carbapenem-resistant infections and those with carbapenem-susceptible infections. Online databases were searched, and data were qualitatively synthesized and pooled in a metaanalysis. Nine studies met inclusion criteria: 6 retrospective case–control studies, 2 retrospective cohort studies, and 1 prospective cohort study. Klebsiella pneumoniae was the causative pathogen in 8 studies; bacteremia was the only infection in 5 studies. We calculated that 26%–44% of deaths in 7 studies were attributable to carbapenem resistance, and in 2 studies, which included bacteremia and other infections, −3% and −4% of deaths were attributable to carbapenem resistance. Pooled outcomes showed that the number of deaths was significantly higher in patients with carbapenem-resistant infections and that the number of deaths attributable to carbapenem resistance is considerable.

Evaluation of a new phenotypic OXA-48 disk test for differentiation of OXA-48 carbapenemase-producing Enterobacteriaceae clinical isolates

The current phenotypic methods for detecting carbapenemase-producing Enterobacteriaceae (CPE) allow differentiation between class A and B carbapenemases, but they cannot confirm in a single test class D OXA-48 carbapenemase producers. In this study, we evaluated a new phenotypic test, the OXA-48 disk test, which is based on an imipenem disk and two blank disks adjacent to the imipenem disk, loaded with the tested strain and impregnated with EDTA and EDTA plus phenyl boronic acid (PBA), respectively. The evaluation of the OXA-48 disk test was performed with 81 genotypically confirmed OXA-48-type-producing Enterobacteriaceae isolates (41 extended-spectrum β-lactamase [ESBL] producers, 3 AmpC producers, and 37 non-ESBL, non-AmpC producers). To measure the specificity of the test, 173 genotypically confirmed OXA-48-negative Enterobacteriaceae isolates (57 Klebsiella pneumoniae carbapenemase [KPC] producers, 34 VIM producers, 23 KPC/VIM producers, 22 NDM producers, and 37 AmpC or ESBL producers and porin deficient) that were nonsusceptible to at least one carbapenem were chosen for testing. Using the imipenem disk and the distortion of the inhibition halo around both blank disks containing EDTA and EDTA/PBA, the test differentiated all but 3 of the 81 OXA-48 producers (sensitivity of 96.3%). The test was negative for OXA-48 production in all but 4 of the 173 carbapenem-nonsusceptible isolates producing other carbapenemases, AmpCs, or ESBLs (specificity of 97.7%). This evaluation shows that the OXA-48 disk test is an accurate phenotypic method for the direct differentiation of OXA-48-producing Enterobacteriaceae. Its use along with combined disk tests employing inhibitor-supplemented carbapenem disks might allow the differentiation of the currently known carbapenemase types in Enterobacteriaceae species and provide important infection control information.

Carbapenemase-producing Enterobacteriaceae

Carbapenemase-producing Enterobacteriaceae (CPE) were almost nonexistent up to the 1990s, but are today encountered routinely in hospitals and other healthcare facilities in many countries including the United States. KPC-producing Klebsiella pneumoniae was the first to emerge and spread globally and is endemic in the United States, Israel, Greece, and Italy. Recently, NDM-producing Enterobacteriaceae and OXA-48-producing K. pneumoniae appear to be disseminating from South Asia and Northern Africa, respectively. They are almost always resistant to all β-lactams including carbapenems and many other classes. Mortality from invasive CPE infections reaches up to 40%. To obtain the maximal benefit from the limited options available, dosing of antimicrobial agents should be optimized based on pharmacokinetic data, especially for colistin and carbapenems. In addition, multiple observational studies have associated combination antimicrobial therapy with lower mortality compared with monotherapy for these infections. The outcomes appear to be especially favorable when patients are treated with a carbapenem and a second agent such as colistin, tigecycline, and gentamicin, but the best approach is yet to be defined.

Comorbidities and disease severity as risk factors for carbapenem-resistant Klebsiella pneumoniae colonization: report of an experience in an internal medicine unit

Background

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an emerging multidrug-resistant nosocomial pathogen, spreading to hospitalized elderly patients. Risk factors in this setting are unclear. Our aims were to explore the contribution of multi-morbidity and disease severity in the onset of CRKP colonization/infection, and to describe changes in epidemiology after the institution of quarantine-ward managed by staff-cohorting.

Methods and Findings

With a case-control design, we evaluated 133 CRKP-positive patients (75 M, 58 F; mean age 79±10 years) and a control group of 400 CRKP-negative subjects (179 M, 221 F; mean age 79±12 years) admitted to Internal Medicine and Critical Subacute Care Unit of Parma University Hospital, Italy, during a 10-month period. Information about comorbidity type and severity, expressed through Cumulative Illness Rating Scale-CIRS, was collected in each patient. During an overall 5-month period, CRKP-positive patients were managed in an isolation ward with staff cohorting. A contact-bed isolation approach was established in the other 5 months. The effects of these strategies were evaluated with a cross-sectional study design. CRKP-positive subjects had higher CIRS comorbidity index (12.0±3.6 vs 9.1±3.5, p<0.0001) and CIRS severity index (3.2±0.4 vs 2.9±0.5, p<0.0001), along with higher cardiovascular, respiratory, renal and neurological disease burden than control group. CIRS severity index was associated with a higher risk for CRKP-colonization (OR 13.3, 95%CI6.88–25.93), independent of comorbidities. Isolation ward activation was associated with decreased monthly incidence of CRKP-positivity (from 16.9% to 1.2% of all admissions) and infection (from 36.6% to 22.5% of all positive cases; p = 0.04 derived by Wilcoxon signed-rank test). Mortality rate did not differ between cases and controls (21.8% vs 15.2%, p = 0.08). The main limitations of this study are observational design and lack of data about prior antibiotic exposure.

Conclusions

Comorbidities and disease severity are relevant risk factors for CRKP-colonization/infection in elderly frail patients. Sanitary measures may have contributed to limit epidemic spread and rate of infection also in internal medicine setting.

Long-term control of carbapenemase-producing Enterobacteriaceae at the scale of a large French multihospital institution: a nine-year experience, France, 2004 to 2012

In 2009, following the occurrence of several outbreaks of carbapenemase-producing Enterobacteriaceae (CPE), a programme for controlling the spread of CPE was implemented in the 38 hospitals of the Assistance Publique-Hôpitaux de Paris, a 21,000-bed institution. This programme included recommendations to isolate, and screen for CPE, patients previously hospitalised abroad, and bundled measures to control cross transmission (barrier precautions, dedicated staff and screening of contact patients). From 2004 to 2012, 140 CPE index cases were identified, 17 leading to outbreaks. After application of the programme, in spite of an increase in the number of CPE index cases epidemiologically linked with a recent stay or hospitalisation abroad, the proportion of cases followed by outbreaks, which was 40% (4/10) before 2009, decreased to 10% (13/130) (p=0.02), and the proportion of secondary cases among all CPE cases decreased from 69% (22/32) to 23% (38/168), (p<0.001). The number of secondary cases varied significantly depending on the speed and strength of the measures implemented around the CPE index case: quick (within two days of patient admission at the hospital) setting of nursing staff dedicated to the patient, quick setting of simple barrier precautions, or delayed measures of control (p=0.001). A sustained and coordinated strategy can lead to control CPE at the level of a large regional multi-hospital institution in a country where CPE are at an emerging stage.

Epidemiology and prevention of carbapenem-resistant Enterobacteriaceae in the United States

Carbapenem-resistant Enterobacteriaceae (CRE) are multidrug-resistant organisms with few treatment options that cause infections associated with substantial morbidity and mortality. CRE outbreaks have been increasingly reported worldwide and are mainly due to the emergence and spread of strains that produce carbapenemases. In the United States, transmission of CRE is primarily driven by the spread of organisms carrying the Klebsiella pneumoniae carbapenemase enzyme, but other carbapenemase enzymes, such as the New-Delhi metallo-β-lactamase, have also emerged. Currently recommended control strategies for healthcare facilities include the detection of patients infected or colonized with CRE and implementation of measures to prevent further spread. In addition to efforts in individual facilities, effective CRE control requires coordination across all healthcare facilities in a region. This review describes the current epidemiology and surveillance of CRE in the United States and the recommended approach to prevention.

[The threat of the carbapenemase-producing enterobacteriaceae in Spain: positioning report of the SEIMC study groups, GEIH and GEMARA]

The emergence and spread of carbapenemase-producing Enterobacteriaceae (CPE), as the current paradigm of extensive drug-resistance and multi-drug resistance to antibiotics, is a serious threat to patient health and public health. The increase in OXA-48- and VIM-1-producing Klebsiella pneumoniae isolates represents the greatest impact of CPE in Spain. This evidence has lead the members of a representative panel of the Spanish Study Groups of Nosocomial Infections and Mechanisms of Action and Resistance to Antimicrobials of the Spanish Society of Clinical Microbiology and Infectious Diseases (GEIH/GEMARA-SEIMC) to make a position statement expressing the need for: (i) definitive and coordinated action by all health professionals and authorities involved, and (ii) an adaptation of health systems to facilitate their early control and minimize their impact.

Modified CLSI extended-spectrum β-lactamase (ESBL) confirmatory test for phenotypic detection of ESBLs among Enterobacteriaceae producing various β-lactamases

The worldwide dissemination of Enterobacteriaceae producing AmpC β-lactamases and carbapenemases makes difficult the phenotypic detection of extended-spectrum β-lactamases (ESBLs), as they may be masked by these additional enzymes. A modification of the CLSI ESBL confirmatory test was developed and evaluated in a comparative study for its ability to successfully detect ESBLs among Enterobacteriaceae producing various carbapenemases (Klebsiella pneumoniae carbapenemase [KPC], VIM, NDM, and OXA-48) and plasmidic or derepressed AmpCs. The modified CLSI ESBL confirmatory test was performed with cefotaxime and ceftazidime disks with and without clavulanate, on which both boronic acid (BA) and EDTA were dispensed. A total of 162 genotypically confirmed ESBL-positive Enterobacteriaceae isolates (83 carbapenemase/ESBL producers, 25 AmpC/ESBL producers, and 54 ESBL-only producers) were examined. For comparison, 139 genotypically confirmed ESBL-negative Enterobacteriaceae isolates (94 of them possessed carbapenemases and 20 possessed AmpCs) were also tested. The standard CLSI ESBL confirmatory test was positive for 106 of the 162 ESBL producers (sensitivity, 65.4%) and showed false-positive results for 4 of the 139 non-ESBL producers (specificity, 97.1%). The modified CLSI ESBL confirmatory test detected 158 of 162 ESBL producers (sensitivity, 97.5%) and showed no false-positive results for non-ESBL producers (specificity, 100%). The findings of the study demonstrate that the modified CLSI ESBL confirmatory test using antibiotic disks containing both BA and EDTA accurately detects ESBLs in Enterobacteriaceae regardless of the coexistence of additional β-lactam resistance mechanisms.

Genomics of KPC-producing Klebsiella pneumoniae sequence type 512 clone highlights the role of RamR and ribosomal S10 protein mutations in conferring tigecycline resistance

Full genome sequences were determined for five Klebsiella pneumoniae strains belonging to the sequence type 512 (ST512) clone, producing KPC-3. Three strains were resistant to tigecycline, one showed an intermediate phenotype, and one was susceptible. Comparative analysis performed using the genome of the susceptible strain as a reference sequence identified genetic differences possibly associated with resistance to tigecycline. Results demonstrated that mutations in the ramR gene occurred in two of the three sequenced strains. Mutations in RamR were previously demonstrated to cause overexpression of the AcrAB-TolC efflux system and were implicated in tigecycline resistance in K. pneumoniae. The third strain showed a mutation located at the vertex of a very well conserved loop in the S10 ribosomal protein, which is located in close proximity to the tigecycline target site in the 30S ribosomal subunit. This mutation was previously shown to be associated with tetracycline resistance in Neisseria gonorrhoeae. A PCR-based approach was devised to amplify the potential resistance mechanisms identified by genomics and applied to two additional ST512 strains showing resistance to tigecycline, allowing us to identify mutations in the ramR gene.

Clinical epidemiology of the global expansion of Klebsiella pneumoniae carbapenemases

Klebsiella pneumoniae carbapenemases (KPCs) were originally identified in the USA in 1996. Since then, these versatile β-lactamases have spread internationally among Gram-negative bacteria, especially K pneumoniae, although their precise epidemiology is diverse across countries and regions. The mortality described among patients infected with organisms positive for KPC is high, perhaps as a result of the limited antibiotic options remaining (often colistin, tigecycline, or aminoglycosides). Triple drug combinations using colistin, tigecycline, and imipenem have recently been associated with improved survival among patients with bacteraemia. In this Review, we summarise the epidemiology of KPCs across continents, and discuss issues around detection, present antibiotic options and those in development, treatment outcome and mortality, and infection control. In view of the limitations of present treatments and the paucity of new drugs in the pipeline, infection control must be our primary defence for now.

Deconstructing the infection control bundles for the containment of carbapenem-resistant Enterobacteriaceae

PURPOSE OF REVIEW

Rates of carbapenem-resistant Enterobacteriaceae (CRE), especially Klebsiella pneumoniae carbapenemase (KPC)-producing Gram-negatives, have increased worldwide. Infections caused by these organisms have been associated with a high mortality, which might be due in part to the limited availability of antibiotic options. Therefore, prevention of acquisition of these organisms is essential. This review summarizes published infection control interventions (bundles) that have been implemented for the control of outbreaks caused by KPC-producing organisms.

RECENT FINDINGS

A total of 15 bundles of interventions aimed at controlling CRE outbreaks are presented. The interventions included combinations of increased compliance with hand hygiene and contact precautions, environmental cleaning, early identification of asymptomatic carriers, and physical separation of CRE-positive patients and their staff. Three bundles had staggered implementation of interventions with their later phase involving a combination of rectal surveillance cultures for identification of asymptomatic CRE carriers, cohorting of CRE-positive patients, and cohorting of the staff caring for CRE carriers. All three staggered bundles successfully decreased their CRE acquisition rates after implementation of their later phases.

SUMMARY

Bundles combine multiple interventions targeting different levels of the transmission pathways and most include increased hand hygiene and contact precautions. However, bundles implemented in phases would seem to indicate that active surveillance cultures and the subsequent cohorting of patients and staff based on these results might be particularly beneficial for controlling horizontal transmission.

Successful control of an outbreak of colonization by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae sequence type 258 in a neonatal intensive care unit, Italy

This article reports an outbreak of colonization by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) sequence type (ST) 258 in a neonatal intensive care unit (NICU) in Palermo, Italy. KPC-Kp ST258 was detected by an active surveillance culture programme. Between 18th September and 14th November 2012, KPC-Kp was isolated from 10 out of 54 neonates admitted in the outbreak period. No cases of infection were recorded. Male sex was associated with colonization, whereas administration of ampicillin- sulbactam plus gentamicin was protective. Infection control interventions interrupted the spread of KPC-Kp without the need to close the NICU to new admissions.