Carbapenem-resistant Enterobacteriaceae in patients admitted to the emergency department: prevalence, risk factors, and acquisition rate

Association of antimicrobial use and incidence of hospital-acquired pneumonia in critically ill trauma patients with pulmonary contusion: an observational study

BACKGROUND

Pneumonia occurs in about 20% of trauma patients with pulmonary contusions. This study aims to evaluate the association between empirical antibiotic therapy and nosocomial pneumonia in this population.

METHODS

Retrospective cohort of adult patients admitted to a trauma-surgical ICU. The Antibiotic Therapy Group (ATG) was defined by intravenous antibiotic use for more than 48 h starting on hospital admission, while the Conservative Group (CG) was determined by antibiotic use no longer than 48 h. Primary outcome was microbiologically documented nosocomial pneumonia within 14 days after hospital admission. Logistic regression was used to estimate the association between group allocation and primary outcome. Exploratory analyses evaluating the association between resistant strains in pneumonia and antibiotic use were performed.

RESULTS

The study included 177 patients with chest trauma and pulmonary contusion on CT scan. ATG were more severely ill than CG, as shown by higher Injury Severity Score, SAPS3, SOFA score, higher rates, and longer duration of mechanical ventilation. In the multivariate analysis, ATG was associated with a lower incidence of primary outcome (OR = 0.25, 95% CI 0.09-0.64; p < 0.01). Similar results were found in the sensitivity analysis with another set of variables. However, each day of antibiotic use was associated with an increased risk of pneumonia by resistant bacteria (OR = 1.18 per day, 95% CI 1.05-1.36; p < 0.01).

CONCLUSIONS

Empiric antibiotic therapy was independently associated with lower incidence of nosocomial pneumonia in critically ill patients with pulmonary contusion. However, each day of antibiotic use was associated with increased resistant strains in infected patients.

Antimicrobial Use and Carbapenem-Resistant Enterobacterales in Korea: A Nationwide Case-Control Study With Propensity Score Matching

BACKGROUND

Nationwide research on the association between carbapenem-resistant Enterobacterales (CREs) and antibiotic use is limited.

METHODS

This nested case-control study analyzed Korean National Health Insurance claims data from April 2017 to April 2019. Based on the occurrence of CRE, hospitalized patients aged ≥ 18 years were classified into CRE (cases) and control groups. Propensity scores based on age, sex, modified Charlson comorbidity score, insurance type, long-term care facility, intensive care unit stay, and acquisition of vancomycin-resistant Enterococci were used to match the case and control groups (1:3).

RESULTS

After matching, the study included 6,476 participants (1,619 cases and 4,857 controls). Multivariable logistic regression analysis revealed that the utilization of broad-spectrum antibiotics, such as piperacillin/tazobactam (adjusted odds ratio [aOR], 2.178; 95% confidence interval [CI], 1.829-2.594), third/fourth generation cephalosporins (aOR, 1.764; 95% CI, 1.514-2.056), and carbapenems (aOR, 1.775; 95% CI, 1.454-2.165), as well as the presence of comorbidities (diabetes [aOR, 1.237; 95% CI, 1.061-1.443], hemiplegia or paraplegia [aOR, 1.370; 95% CI, 1.119-1.679], kidney disease [aOR, 1.312; 95% CI, 1.105-1.559], and liver disease [aOR, 1.431; 95% CI, 1.073-1.908]), were significantly associated with the development of CRE. Additionally, the CRE group had higher mortality (8.33 vs. 3.32 incidence rate per 100 person-months, P < 0.001) and a total cost of healthcare utilization per person-month (15,325,491 ± 23,587,378 vs. 5,263,373 ± 14,070,118 KRW, P < 0.001) than the control group.

CONCLUSION

The utilization of broad-spectrum antibiotics and the presence of comorbidities are associated with increasing development of CRE. This study emphasizes the importance of antimicrobial stewardship in reducing broad-spectrum antibiotic use and CRE disease burden in Korea.

The pharmacokinetics/pharmacodynamics of ceftazidime/avibactam for central nervous system infections caused by carbapenem-resistant Gram-negatives: a prospective study

OBJECTIVES

To describe the pharmacokinetics/pharmacodynamics (PK/PD) of ceftazidime/avibactam in critically ill patients with CNS infections.

METHODS

A prospective study of critically ill patients with CNS infections who were treated with ceftazidime/avibactam and the steady-state concentration (Css) of ceftazidime/avibactam in serum and/or CSF was conducted between August 2020 and May 2023. The relationship between PK/PD goal achievement, microbial eradication and the clinical efficacy of ceftazidime/avibactam was evaluated.

RESULTS

Seven patients were finally included. The ceftazidime/avibactam target attainment in plasma was optimal for three, quasi-optimal for one and suboptimal for three. In three patients with CSF drug concentrations measured, ceftazidime/avibactam target attainment in CSF was 100% (3/3), which was optimal. The AUCCSF/serum values were 0.59, 0.44 and 0.35 for ceftazidime and 0.57, 0.53 and 0.51 for avibactam. Of the seven patients, 100% (7/7) were treated effectively, 71.4% (5/7) achieved microbiological eradication, 85.7% (6/7) survived and 14.3% (1/7) did not survive.

CONCLUSIONS

The limited clinical data suggest that ceftazidime/avibactam is effective in the treatment of CNS infections caused by MDR Gram-negative bacilli (MDR-GNB), can achieve the ideal drug concentration of CSF, and has good blood-brain barrier penetration.

Who should be screened for carbapenemase-producing Enterobacterales and when? A systematic review

Carbapenemase-producing Enterobacterales (CPE) cases increases every year in Denmark and the proportion of CPE-positive cases with a travel history decreases. Several epidemiological links show transmission in Danish healthcare setting indicating infection prevention and control challenges and raising questions about the Danish CPE screening protocol. The aim of this review was to identify additional risk factors to those described in the Danish CPE-screening protocol in order to detect the Danish CPE-positive patients and thereby reduce the risk of transmission and outbreaks. A systematic literature search was conducted in PubMed, Embase and Cochrane Library during March 2022. A total of 1487 articles were screened, and 19 studies were included. Retrieved studies dealt with patients with laboratory-confirmed CPE (colonization and/or infection) and associated risk factors. Antimicrobial therapy, especially broad-spectrum antimicrobial agents, prior or current hospitalization of approximately one week in ICU and 20-28 days in other wards and travel history with or without hospitalization abroad were significant risk factors associated with CPE acquisition. Comorbidities and invasive procedures were identified as risk factors, but without identifying specific comorbidities or invasive procedures associated with risk for CPE-acquisition. This study suggests the need to develop an additional algorithm for CPE-screening in Denmark. In addition to risk-based screening on admission, screening of inpatients should be considered. The screening protocol might include screening of inpatients with comorbidities who are hospitalized >1 week in ICU or >3 weeks in other wards and who have previously received or currently are receiving antibiotic treatment. Further research is needed to develop a new CPE-screening algorithm.

Fecal Carriage of Carbapenem Resistant Enterobacterales and Associated Factors Among Admitted Patients in Saint Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia

Purpose

The Enterobacterales family colonizes the human gut as normal flora in all age groups, with bacterial infections being the most common cause. Resistance is currently observed in all normal flora. The aim of this study was to determine the frequency of fecal carriage of carbapenem-resistant Enterobacterales (CRE), carbapenemase-producing Enterobacterales (CPE), and associated factors in the faeces of admitted patients.

Methods

A cross-sectional study was conducted in Saint Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia. A total of 384 rectal swabs were collected from various wards in admitted patients who have consented to participate. The specimens were inoculated on a MacConkey agar plate, and then they were incubated at 37 °C for 18 to 24 hours. Using the BD PhoenixTM M50 compact system identification and antimicrobial susceptibility testing were performed. Using the modified carbapenem inactivation method, it was determined whether the carbapenem-resistant bacterial isolate produced carbapenemase or not.

Results

Overall prevalence of carbapenem-resistant Enterobacterales carriage and carbapenemase producing Enterobacterales in admitted patients was 17.2% (95%, Confidence Interval: 13.3-21.1%) and 7% (95%, Confidence Interval: 4.7-9.9%), respectively. The predominate carbapenem-resistant Enterobacterales in fecal carriage was K. pneumoniae, 15.4% (23/149), E. cloacae 15.4% (6/39), followed by E. coli 12.4% (37/307) of carbapenem-resistant Enterobacterales (CRE) isolate. Carbapenem-resistant Enterobacterales carriage isolates showed large level of resistance to ciprofloxacin, and sulfamethoxazole-trimethoprim. Prior intake of antibiotics (Odds Ratio 2.42, 95% CI: 11.186-4.95) was significantly associated with higher carbapenem-resistant Enterobacterales carriage.

Conclusion

We observed a high prevalence of carbapenem-resistant Enterobacterales carriage and carbapenemase-producing Enterobacterales among admitted patients. There were only amikacin and colistin that could be effective for carbapenem-resistant Enterobacterales isolates. Hence, the control of carbapenem-resistant Enterobacterales carriage should be given priority by carbapenem-resistant Enterobacterales screening for fecal of admitted patients, and adhering to good infection prevention practice in hospital settings.

Comparison of Risk Stratification Approaches to Identify Patients with Clostridioides difficile Infection at Risk for Multidrug-Resistant Organism Gut Microbiota Colonization

INTRODUCTION

Multidrug-resistant organisms (MDRO) commonly colonize the gut microbiota of patients with Clostridioides difficile infection (CDI). This increases the likelihood of systemic infections with these MDROs. To help guide MDRO screening and/or empiric antibiotic therapy, we derived and compared predictive indices for MDRO gut colonization in patients with CDI.

METHODS

This was a multicenter, retrospective cohort study of adult patients with CDI from July 2017 to April 2018. Stool samples were screened for MDRO via growth and speciation on selective antibiotic media and confirmed using resistance gene polymerase chain reaction. A regression-based risk score for MDRO colonization was constructed. Predictive performance via area under the receiver operating characteristic curve (aROC) of this index was compared with two other simplified risk stratification approaches: (1) prior healthcare exposure and/or high-CDI risk antibiotics; (2) number of prior high-CDI risk antibiotics.

RESULTS

50 (20.8%) of 240 included patients had MDRO colonization; 35 (14.6%) VRE, 18 (7.5%) MRSA, 2 (0.8%) CRE. Prior fluoroquinolone (aOR 2.404, 95% CI 1.095-5.279) and prior vancomycin (1.996, 95% CI 1.014-3.932) were independently associated with MDRO colonization while prior clindamycin (aOR 3.257, 95% CI 0.842-12.597) and healthcare exposure (aOR 2.138, 95% CI 0.964-4.740) were retained as explanatory variables. The regression-based risk score significantly predicted MDRO colonization (aROC 0.679, 95% CI 0.595-0.763), but was not significantly more predictive than prior healthcare exposure + prior antibiotics (aROC 0.646, 95% CI 0.565-0.727) or number of prior antibiotic exposures (aROC 0.642, 95% CI 0.554-0.730); P > 0.05 for both comparisons.

CONCLUSION

A simplified approach using prior healthcare exposure and receipt of prior antibiotics known to increase CDI risk identified patients at risk for MDRO gut microbiome colonization as effectively as individual patient/antibiotic risk modeling.

Transmission of Carbapenem-Resistant Enterobacterales in an Overcrowded Emergency Department: Controlling the Spread to the Hospital

BACKGROUND

Overcrowded emergency departments (EDs) may increase the risk of carbapenem-resistant Enterobacterales (CRE) transmission.

METHODS

We conducted a quasi-experimental study divided into 2 phases (baseline and intervention) to investigate the impact of an intervention on the acquisition rate and identify risk factors for CRE colonization in an ED of a tertiary academic hospital in Brazil. In both phases, we did universal screening with rapid molecular test (blaKPC, blaNDM, blaOXA48, blaOXA23, and blaIMP) and culture. At baseline, both screening test results were not reported, and patients were put under contact precautions (CP) based on previous colonization or infection by multidrug-resistant organisms. During the intervention, all patients hospitalized in the ED were placed in empiric CP and the result of CRE screening was reported; if negative, patients were released from CP. Patients were rescreened if they stayed >7 days in the ED or were transferred to an intensive care unit.

RESULTS

A total of 845 patients were included: 342 in baseline and 503 in intervention. Colonization at admission was 3.4% by culture and molecular test. Acquisition rates during ED stay dropped from 4.6% (11/241) to 1% (5/416) during intervention (P = .06). The aggregated antimicrobial use in the ED decreased from phase 1 to phase 2 (804 defined daily doses [DDD]/1000 patients to 394 DDD/1000 patients, respectively). Length of stay >2 days in the ED was a risk factor for CRE acquisition (adjusted odds ratio, 4.58 [95% confidence interval, 1.44-14.58]; P = .01).

CONCLUSIONS

Early empiric CP and rapid identification of CRE-colonized patients reduce cross-transmission in ED. Nevertheless, staying >2 days in ED compromised efforts.

Crude Mortality Associated With the Empirical Use of Polymyxins in Septic Patients in a Setting of High Prevalence of Carbapenem-Resistant Gram-negative Bacteria: Retrospective Analysis of a Cohort

BACKGROUND

Our aim in this retrospective cohort study was to assess the impact on mortality of the empirical use of polymyxin as therapy for carbapenem-resistant gram-negative bacteria (CR-GNB) in septic patients. The study was performed at a tertiary academic hospital in Brazil, from January 2018 to January 2020, the pre-coronavirus disease 2019 period.

METHODS

We included 203 patients with suspected sepsis. The first doses of antibiotics were prescribed from a "sepsis antibiotic kit", which contained a selection of drugs, including polymyxin, with no preapproval policy. We developed a logistic regression model to assess risk factors associated with 14-day crude mortality. Propensity score for polymyxin was used to control biases.

RESULTS

Seventy (34%) of 203 patients had infections with at least 1 multidrug-resistant organism isolated from any clinical culture. Polymyxins in monotherapy or in combination therapy were prescribed to 140 of the 203 (69%) patients. The overall 14-day mortality rate was 30%. The 14-day crude mortality was associated with age (adjusted odds ratio [aOR], 1.03; 95% confidence interval [CI], 1.01-1.05; P = .01), SOFA (sepsis-related organ failure assessment) score value (aOR, 1.2; 95% CI, 1.09-1.32; P < .001), CR-GNB infection (aOR, 3.94; 95% CI, 1.53-10.14; P = .005), and time between suspected sepsis and antibiotic administration (aOR, 0.73; 95% CI, .65-.83; P < .001). The empirical use of polymyxins was not associated with decreased crude mortality (aOR, 0.71; 95% CI, .29-1.71; P = .44).

CONCLUSIONS

Empirical use of polymyxin for septic patients in a setting with high CR-GNB prevalence was not associated with decreased crude mortality.

Epidemiology and Risk Factors of Carbapenemase-Producing Enterobacteriaceae Acquisition and Colonization at a Korean Hospital over 1 Year

Background: Carbapenemase-producing Enterobacteriaceae (CPE) are known to be primarily responsible for the increasing spread of carbapenem-resistant Enterobacteriaceae and have therefore been targeted for preventing transmission and appropriate treatment. This study aimed to describe the clinical and epidemiological characteristics and risk factors of CPE infection in terms of acquisition and colonization. Methods: We examined patients' hospital data, including active screening on patients' admission and in intensive care units (ICUs). We identified risk factors for CPE acquisition by comparing the clinical and epidemiological data of CPE-positive patients between colonization and acquisition groups. Results: A total of 77 CPE patients were included (51 colonized and 26 acquired). The most frequent Enterobacteriaceae species was Klebsiella pneumoniae. Among CPE-colonized patients, 80.4% had a hospitalization history within 3 months. CPE acquisition was significantly associated with treatment in an ICU [adjusted odds ratio (aOR): 46.72, 95% confidence interval (CI): 5.08-430.09] and holding a gastrointestinal tube (aOR: 12.70, 95% CI: 2.61-61.84). Conclusions: CPE acquisition was significantly associated with ICU stay, open wounds, holding catheters or tubes, and antibiotic treatment. Active CPE screening should be implemented on admission and periodically for high-risk patients.

Repositioning of Benzodiazepine Drugs and Synergistic Effect with Ciprofloxacin Against ESKAPE Pathogens

Infectious diseases are among the leading causes of morbidity and mortality worldwide. Combating them becomes more complex when caused by the pathogens of the ESKAPE group, which are Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. The purpose of this study was to investigate the repositioning potential of the benzodiazepines clonazepam and diazepam individually and in combination with the antibacterial ciprofloxacin against ESKAPE. The minimum inhibitory concentration and minimum bactericidal concentration against seven American Type Culture Collection (ATCC) reference standard strains and 64 ESKAPE clinical isolates were determined. In addition, the interaction with ciprofloxacin was determined by the checkerboard method and fractional inhibitory concentration index (FICI) of clonazepam against 11 ESKAPE and diazepam against five ESKAPE. We also list the results found and their clinical significance. Benzodiazepines showed similar antibacterial activity against Gram-positive and Gram-negative. The checkerboard and FICI results showed a synergistic effect of these drugs when associated with ciprofloxacin against almost all tested isolates. Viewing the clinical cases studied, benzodiazepines have potential as treatment alternatives. The results allow us to conclude that clonazepam and diazepam, when in combination with ciprofloxacin, have promising activity against ESKAPE, therefore, assuming the position of candidates for repositioning.

Characterization of KPC-2-producing Klebsiella pneumoniae and affected patients of a pediatric hospital in Brazil

Carbapenemase-producing Klebsiella pneumoniae (CPKp) infections are important threats to pediatric populations. Thus, a retrospective study was conducted in a Brazilian reference pediatric hospital, and 26 CPKp isolates obtained from 23 patients were characterized. The affected population had important underlying diseases, reflecting previous hospitalization and antibiotic use. Most CPKp isolates were resistant to all antibiotic classes, and bla_KPC-2 was the only carbapenemase-encoding gene. bla_CTX-M-15 was common among the isolates, and modification or absence of the mgrB gene was the cause of polymyxin B resistance. Ten different sequence types were identified, and clonal complex 258 was prevalent. Alleles wzi50 and wzi64 were the most recurrent ones regarding K-locus type, with a remarkable contribution of the epidemic ST11/KL64 lineage as a colonizer. Our findings show that lineages associated with the pediatric population are similar to those found in adults, reinforcing the need for epidemiological surveillance to effectively implement prevention and control measures.

Prevalence and incidence of carbapenem-resistant K. pneumoniae colonization: systematic review and meta-analysis

BACKGROUND

Klebsiella pneumoniae is a gram-negative rod belonging to the order Enterobacterales and having a wide distribution in the environment, including the human colon. Recently, the bacterium is one of the known problems in the healthcare setting as it has become resistant to last-resort drugs like carbapenems. The colonized person can serve as a reservoir for his/herself and others, especially in the healthcare setting leading to nosocomial and opportunistic infections. Therefore, we aimed to quantitatively estimate the rate of prevalence and incidence of colonization with carbapenem-resistant K. pneumoniae.

METHODS

A literature search was conducted on PubMed/MEDLINE, Google Scholar, Science Direct, Cochrane Library, WHO Index Medicus, and university databases. The study includes all published and unpublished papers that addressed the prevalence or incidence of K. pneumoniae colonization. Data were extracted onto format in Microsoft Excel and pooled estimates with a 95% confidence interval calculated using Der-Simonian-Laird random-effects model. With the use of I² statistics and prediction intervals, the level of heterogeneity was displayed. Egger's tests and funnel plots of standard error were used to demonstrate the publication bias.

RESULTS

A total of 35 studies were included in the review and 32 records with 37,661 patients for assessment of prevalence, while ten studies with 3643 patients for incidence of colonization. The prevalence of carbapenem-resistant K. pneumoniae colonization varies by location and ranges from 0.13 to 22%, with a pooled prevalence of 5.43%. (3.73-7.42). Whereas the incidence of colonization ranges from 2 to 73% with a pooled incidence of 22.3% (CI 12.74-31.87), both prevalence and incidence reports are majorly from developed countries. There was a variation in the distribution of carbapenem resistance genes among colonizing isolates with KPC as a prominent gene reported from many studies and NDM being reported mainly by studies from Asian countries. A univariate meta-regression analysis indicated continent, patient type, study design, and admission ward do not affect the heterogeneity (p value>0.05).

CONCLUSION

The review revealed that colonization with K. pneumoniae is higher in a healthcare setting with variable distribution in different localities, and resistance genes for carbapenem drugs also have unstable distribution in different geographic areas.

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.

A Seven-Year Microbiological and Molecular Study of Bacteremias Due to Carbapenemase-Producing Klebsiella Pneumoniae: An Interrupted Time-Series Analysis of Changes in the Carbapenemase Gene's Distribution after Introduction of Ceftazidime/Avibactam

Background: Ceftazidime/avibactam (CZA) is a new option for the treatment of KPC-producing Klebsiella pneumoniae. The aim of this study was to determine resistance patterns and carbapenemase genes among K. pneumoniae (CP-Kp) bacteremic isolates before and after CZA introduction. Methods: K. pneumoniae from blood cultures of patients being treated in a Greek university hospital during 2015−21 were included. PCR for blaKPC, blaVIM, blaNDM and blaOXA-48 genes was performed. Results: Among 912 K. pneumoniae bacteremias: 725 (79.5%) were due to carbapenemase-producing isolates; 488 (67.3%) carried blaKPC; 108 (14.9%) blaVIM; 100 (13.8%) blaNDM; and 29 (4%) carried a combination of blaKPC, blaVIM or blaNDM. The incidence of CP-Kp bacteremias was 59 per 100,000 patient-days. The incidence of CP-Kp changed from a downward pre-CZA trend to an upward trend in the CZA period (p = 0.007). BSIs due to KPC-producing isolates showed a continuous downward trend in the pre-CZA and CZA periods (p = 0.067), while BSIs due to isolates carrying blaVIM or blaNDM changed from a downward trend in the pre-CZA to an upward trend in the CZA period (p < 0.001). Conclusions: An abrupt change in the epidemiology of CP-Kp was observed in 2018, due to the re-emergence of VIM-producing isolates after the suppression of KPC-producing ones via the use of CZA.

Active Surveillance for Carbapenem-Resistant Enterobacterales (CRE) Colonization and Clinical Course of CRE Colonization among Hospitalized Patients at a University Hospital in Thailand

Optimal measures for preventing and controlling carbapenem-resistant Enterobacterales (CRE) depend on their burden. This prospective observational study investigated the prevalence and clinical course of CRE colonization in hospitalized patients at Siriraj Hospital, the largest university hospital in Thailand. Stool/rectal swab samples were collected from the patients upon admission, once weekly during hospitalization and every 1–3 months after discharge, to determine the presence of CRE in the stool. Between 2018 and 2021, a total of 528 patients were included. The prevalence of CRE colonization upon admission was 15.5%, while 28.3% of patients who tested negative for CRE on admission acquired CRE during their hospitalization. CRE colonization upon admission was usually associated with prior healthcare exposure. Among CRE-colonized patients, 4.7% developed a CRE clinical infection, with 60% mortality. No cutoff period that ensured that patients were free of CRE colonization in stool was identified, and isolation precautions should only be ceased if stool tests are negative for CRE. In conclusion, the prevalence of CRE colonization among hospitalized patients at Siriraj Hospital is high. CRE-colonized patients are at risk of developing subsequent CRE infection. To prevent CRE transmission within the hospital, patients at high risk of colonization should undergo CRE screening upon admission.

Prevalence of faecal carriage of Carbapenemase Producing Enterobacteriaceae in healthy Indian subjects from the community

PURPOSE

Faecal carriage of carbapenemase-producing Enterobacterales (CPE) has been extensively investigated in hospitalized patients, but limited data is available on the carriage rate in healthy individuals in India.

METHODS

A total of 1000 stool samples were screened for CPE from healthy individuals in Chennai (n ​= ​50), Hyderabad (n ​= ​184) and Mumbai (n ​= ​766). Diluted stool samples were cultured on chromID CARBA SMART plates. Growing colonies were screened for CPE by RAPIDEC® CARBA NP Test and minimum inhibitory concentration (MIC) of imipenem by E-Test. PCR was performed for confirmation of CPE genes.

RESULTS

Out of the 1000 stool samples tested, 6.1% were positive for CPE. A total of 64 carbapenem resistant isolates (56 ​E.coli, 4 Klebsiella pneumoniae, 3 Enterobacter cloacae and 1 Citrobacter freundii) were recovered from ChromID CARBA SMART biplate. Carbapenemase production was identified in 57/64 isolates by RAPIDEC® CARBA NP test. PCR analysis showed 28 bla_NDM-1 and 33 bla_OXA48. Three remaining isolates (2 ​E.coli, 1 ​K.pneumoniae) were negative for the tested carbapenemase genes. Interestingly, out of these 61 PCR positive isolates, 49.1% displayed imipenem MIC within the susceptibility range on the basis of CLSI interpretative criteria.

CONCLUSIONS

Faecal carriage of CPE among healthy individuals was 6.1%. Comprehensive measures to improve the sanitation scenario and implementation of National AMR action plan are needed to prevent further generation and dissemination of carbapenem resistant Enterobacterales (CRE).

Epidemiology of Carbapenem-Resistant Enterobacterales Infection and Colonization in Hospitalized Patients at a University Hospital in Thailand

Purpose

To investigate the epidemiology of carbapenem-resistant Enterobacterales (CRE) colonization or CRE infection relative to the natural history and clinical course of CRE colonization or CRE infection in hospitalized patients during admission and after discharge.

Material and Methods

Two adult cohorts were enrolled. Cohort I comprised hospitalized patients who had CRE isolated from their clinical specimens during 2018–2020. CRE colonization or CRE infection was based on the absence/presence of clinical features of infection. Information regarding the natural history and clinical course of these patients was collected during hospitalization. Stool samples were evaluated for CRE once a week during hospitalization, and then once every few months after discharge until negative for CRE. Cohort II comprised patients who had CRE isolated from clinical specimens during hospitalization and who were discharged during 2015–2018. CRE in stool samples collected from these patients every few months was assessed to determine duration of CRE in stool.

Results

CRE in stool was detected in 69.7% of 353 patients in cohort I. K. pneumoniae was the predominant CRE isolated from clinical samples (76.8%) and stool samples (65.7%). Among the 225 CRE-colonized patients, 20.4% developed subsequent CRE infections with a median duration from CRE colonization to CRE infection of 14 days. Among 174 CRE-infected patients, the most common infection was pneumonia with mortality at discharge of 47.7%. Duration of CRE colonization in stool was <1 year in 50.0% of cohort I patients, and <2 years in 91.4% of patients in cohort II.

Conclusion

CRE isolated from clinical specimens in hospitalized patients are more likely to cause colonization than infection. Patients with CRE colonization are at risk of subsequent CRE infection with high mortality. Stool culture for CRE is needed to verify if contact precautions can be discontinued because the duration of CRE colonization in stool varied from days to years.

Intestinal Colonization Due to Carbapenem-Resistant Enterobacteriaceae Among Hematological Malignancy Patients in India: Prevalence and Molecular Charecterisation

Faecal carriage of Carbapenem-resistant Enterobacteriaceae (CRE) is being observed as an important risk factor for bacteremia among patients with hematological malignancies. A prospective surveillance study was conducted among these patients to determine the gut colonization of CRE. Rectal/perianal swabs were collected to isolate CRE. Carbapenem resistance was detected by disk diffusion, modified-Hodge, Carba-NP test, and PCR for ^bla NDM-1, ^bla KPC, ^bla OXA-48, ^bla VIM, ^bla IMP genes. A total of 209 CRE isolates were identified from 151 patients. E. coli was the most common (83.2%) CRE identified, followed by Klebsiella spp. (9.6%). The majority of CRE were observed resistant to ertapenem (86%). ^bla NDM-1 was the most common gene (57.3%), followed by ^bla OXA-48 (37.8%). 26.8% isolates found to carry both ^bla NDM-1 and ^bla OXA-48 genes. CRE is increasingly observed to cause bacteremia among hematological malignancy patients due to increased colonization. Screening for gut CRE colonization is necessary to guide empirical therapy and apply infection control measures among these patients.

Colonization with multiresistant bacteria in acute hospital care: the association of prior antibiotic consumption as a risk factor

BACKGROUND

Antibiotic resistance poses a worldwide threat and knowledge concerning risk factors for colonization with multiresistant bacteria (MRB) is limited.

OBJECTIVES

To examine the impact of prior antibiotic consumption on MRB colonization, with focus on type of antibiotic and timeline between antibiotic prescription and MRB colonization.

METHODS

A nationwide case-control study was conducted and adults visiting emergency departments were invited to participate. All patients were swabbed in the throat, nose and rectum, and analysed for colonization with ESBL-producing Enterobacteriaceae (ESBL-E), MRSA, carbapenemase-producing enterobacteria and VRE. Antibiotic history 2 years prior to enrolment was collected at an individual level through a national register. Multivariate analyses were performed to examine the association between antibiotic consumption and MRB status. A subgroup analysis of ESBL-E-colonized cases was made.

RESULTS

We included 256 patients colonized with MRB and 4763 controls. In the 2 years prior to study inclusion, 77% of cases and 68% of controls had at least one antibiotic prescription (P = 0.002). We found a significant increase in risk of colonization with ESBL-E if penicillins (OR = 1.58-1.65) or fluoroquinolones (OR = 2.25-6.15) were prescribed. The analysis of all MRB-colonized patients showed similar results. An assessment of the timeline showed a significant increase in risk of colonization up to 2 years after exposure to penicillins, fluoroquinolones and macrolides.

CONCLUSIONS

The prevalence of ESBL-E colonization was related to fluoroquinolone, macrolide and penicillin consumption for at least 2 years after antibiotic treatment.

Establishing a quantitative index of meropenem hydrolysis for the detection of KPC- and NDM-producing bacteria by MALDI-TOF MS

BACKGROUND

Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS), commonly used for microorganism identification, can also be applied for the detection of carbapenemase-producing bacteria by the evaluation of carbapenem hydrolysis. Since KPC- and NDM-producing bacteria are related to high mortality rates, diagnostic assays for its detection are essential. The aim of this study was to develop and evaluate a method to establish a quantitative measure (hydrolysis index - HI) to detect meropenem hydrolysis by MLADI-TOF MS.

METHODS

bla_KPC and bla_NDM positive and negative Klebsiella pneumoniae isolates and Escherichia coli ATCC 25922 (control) were incubated in a meropenem solution for 2 h. Protein extraction from these suspensions were submitted to MALDI-TOF MS analysis. The intensity of peaks at 384 m/z and 379 m/z of each isolate were used to establish the HI as follows: HI = (Peak intensity_{384 Test} / Peak intensity_{379 Test}) / (Peak intensity_{384 Control} / Peak intensity_{379 Control}). Receiver Operating Characteristic curve was used to determine a cutoff value to differentiate carbapenemase-producing from carbapenemase non-producing bacteria.

RESULTS

As all carbapenemase-producing K. pneumoniae presented HI ≤0.55 and all carbapenemase non-producing isolates presented a HI ≥0.57, the index of 0.56 was established as a cutoff value to differentiate carbapenemase (KPC and NDM) producing and non-producing bacteria.

Diagnostic stewardship based on patient profiles: differential approaches in acute versus chronic infectious syndromes

Introduction: New diagnostics may be useful in clinical practice, especially in contexts of high prevalence of multidrug-resistant organisms (MDRO). However, misuse of diagnostic tools may lead to increased costs and worse patient outcome. Conventional and new techniques should be appropriately positioned in diagnostic algorithms to guide an appropriate use of antimicrobial therapy.Areas covered: A panel of experts identified 4 main areas in which the implementation of diagnostic stewardship is needed. Among chronic infections, bone and prosthetic joint infections and subacute-chronic intravascular infections and endocarditis represent common challenges for clinicians. Among acute infections, bloodstream infections and community-acquired pneumonia may be associated with high mortality and require appropriate diagnostic approach.Expert opinion: Diagnostic stewardship aims to improve the appropriate use of microbiological diagnostics to guide therapeutic decisions through appropriate and timely diagnostic testing. Here, diagnostic algorithms based on different patient profiles are proposed for chronic and acute clinical syndromes. In each clinical scenario, combining conventional and new diagnostic techniques is crucial to make a rapid and accurate diagnosis and to guide the selection of antimicrobial therapy. Barriers related to the implementation of new rapid diagnostic tools, such as high initial costs, may be overcome through their rational and structured use.

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

Purpose

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

Patients and Methods

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

Results

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

Conclusion

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

Carriage of Carbapenem-Resistant Enterobacterales in Adult Patients Admitted to a University Hospital in Italy

The emerging spread of carbapenemase-producing Enterobacterales (CPE) strains, in particular, Klebsiella pneumoniae and Escherichia coli, has become a significant threat to hospitalized patients. Carbapenemase genes are frequently located on plasmids than can be exchanged among clonal strains, increasing the antibiotic resistance rate. The aim of this study was to determine the prevalence of CPE in patients upon their admission and to analyze selected associated factors. An investigation of the antibiotic resistance and genetic features of circulating CPE was carried out. Phenotypic tests and molecular typing were performed on 48 carbapenemase-producing strains of K. pneumoniae and E. coli collected from rectal swabs of adult patients. Carbapenem-resistance was confirmed by PCR detection of resistance genes. All strains were analyzed by PCR-based replicon typing (PBRT) and multilocus sequence typing (MLST) was performed on a representative isolate of each PBRT profile. More than 50% of the strains were found to be multidrug-resistant, and the bla_KPC gene was detected in all the isolates with the exception of an E. coli strain. A multireplicon status was observed, and the most prevalent profile was FIIK, FIB KQ (33%). MLST analysis revealed the prevalence of sequence type 512 (ST512). This study highlights the importance of screening patients upon their admission to limit the spread of CRE in hospitals.

Clinical Microbiology in the Intensive Care Unit: Time for Intensivists to Rejuvenate this Lost Art

We live in an era of evolving microbial infections and equally evolving drug resistance among microorganisms. In any healthcare facility, intensivists play the most pivotal role with critically ill patients under their direct care. Majority of the critically ill patients already harbor a microorganism at admission or acquire one in the form of healthcare-associated infections during their course of intensive care unit stay. It is therefore rather imperative for intensivists to possess sound knowledge in clinical microbiology. On a negative note, most clinicians have very meager and remote knowledge acquired during their undergraduate years. This knowledge is rather theoretical than applied and wanes over the years becoming nonbeneficial in intensive patient care. We, therefore, intend to explore important concepts in applied microbiology and infection control that intensivists should know and implement in their clinical practice on a day-to-day basis.

How to cite this article: Princess I, Vadala R. Clinical Microbiology in the Intensive Care Unit: Time for Intensivists to Rejuvenate this Lost Art. Indian J Crit Care Med 2021;25(5):566–574.

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.

Xpert Carba-R assay for detection of carbapenemase-producing organisms in patients admitted to emergency rooms

Carbapenemase-producing organisms (CPO) have been identified as an urgent healthcare threat. Various methods have been used for the detection of CPO using rectal swabs. Recently, an on-demand polymerase chain reaction (PCR) assay, namely, the Xpert Carba-R assay, that requires less than an hour of turnaround time, had been developed for CPO detection in clinical samples. This study focused on the use of this assay to determine the intestinal colonization rate of CPO in patients admitted to emergency rooms (ERs).A retrospective review of medical records was conducted at a tertiary hospital between July 2017 and June 2018. CPO screening using rectal swabs was performed for patients transferred from other hospitals or for those who tested positive in CPO culture tests in the previous three months. The Xpert Carba-R assay and culture tests were used as the CPO screening methods, and the results of both tests were compared.Medical records of 705 patients admitted to our hospital during the study period were reviewed. Of these, 31 (4.4%) showed positive results for CPO using the Xpert Carba-R assay, and these patients were then transferred from the ERs to isolation rooms. Fifteen of the Xpert Carba-R assay-positive patients were also positive for the culture test; hence, early detection enabled the rapid isolation of CPO-infected patients and prevented the spread of the CPO.The Xpert Carba-R assay is a rapid test to identify and guide infection control programs to contain the spread of the rectal colonization of CPO within a hospital.

Multicenter Evaluation of Xpert Carba-R Assay for Detection and Identification of the Carbapenemase Genes in Rectal Swabs and Clinical Isolates

Rapid detection of carbapenemase-producing organisms is clinically desirable for hospital infection control and antibiotic stewardship. In this multicenter study, the Xpert Carba-R assay was evaluated for detection of the five carbapenemase genes (bla_KPC, bla_NDM, bla_IMP, bla_OXA-48, and bla_VIM) in 2404 nonduplicate rectal swabs of admitted inpatients and 521 Gram-negative isolates from four tertiary hospitals in China, compared with the reference growth-based method with DNA sequence analysis of colonies. All suspected false-positive results in rectal swabs were resolved by supplementary sequencing from broth cultures. A total of 197 bla_KPC, 171 bla_NDM, 142 bla_IMP, 6 bla_VIM, and 5 bla_OXA-48 genes were detected by Xpert Carba-R in 417 rectal swabs, with overall positive and negative percentage agreements ranging from 94.5% to 100% and from 94.8% to 99.9%, respectively. Notably, 17.5% (263/1500) of inpatients had rectal colonization with carbapenem-nonsusceptible organisms detected in intensive care units, and 63.1% (166/263) were Xpert Carba-R positive. Among the 469 carbapenem-nonsusceptible and 52 carbapenem-susceptible isolates examined, 373 were Enterobacteriaceae, 55 were Pseudomonas aeruginosa, and 93 were Acinetobacter baumannii. Compared with the reference isolate sequencing, overall positive and negative percentage agreements were 99.7% and 98.0%, respectively. The intra-assay and interassay coefficient of variability values were both <2%. Thus, we show that Xpert Carba-R assay provides good reproducibility and reliable results for detection and differentiation of five carbapenemase genes in both rectal swabs and clinical isolates.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Update on the epidemiology of carbapenemases in Latin America and the Caribbean

INTRODUCTION

Carbapenemases are β-lactamases able to hydrolyze a wide range of β-lactam antibiotics, including carbapenems. Carbapenemase production in Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter spp., with and without the co-expression of other β-lactamases is a serious public health threat. Carbapenemases belong to three main classes according to the Ambler classification: class A, class B, and class D.

AREAS COVERED

Carbapenemase-bearing pathogens are endemic in Latin America. In this review, we update the status of carbapenemases in Latin America and the Caribbean.

EXPERT OPINION

Understanding the current epidemiology of carbapenemases in Latin America and the Caribbean is of critical importance to improve infection control policies limiting the dissemination of multi-drug-resistant pathogens and in implementing appropriate antimicrobial therapy.

Acquisition of MDR-GNB in hospital settings: a systematic review and meta-analysis focusing on ESBL-E

INTRODUCTION

Extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) and other multi-drug-resistant Gram-negative bacteria (MDR-GNB) have disseminated globally since their discovery in the late 20^th century. Various infection prevention and control measures are in place to prevent nosocomial transmission of these organisms, but their efficacy remains disputed. New literature has emerged in recent years providing further evidence which can be used to formulate effective strategies to tackle this issue in the future.

METHODS

A systematic review was performed to characterize the prevalence of colonization of multi-drug-resistant organisms and subsequent acquisition of these organisms within hospital settings. A meta-analysis was performed to characterize the prevalence and acquisition of ESBL-E in Europe and North America.

RESULTS

Twenty-eight studies fulfilled the inclusion criteria. Escherichia coli formed the main burden of MDR-GNB colonization worldwide. Patient-to-patient transmission of ESBL-E was found to be rare, but increased transmissibility of Klebsiella pneumoniae was described over E. coli. Within European and North American healthcare settings, a meta-analysis of eight studies identified a pooled prevalence of ESBL-E on admission to hospital of 7.91% and an acquisition rate of 3.73%.

DISCUSSION

Low prevalence at the point of hospital admission and insufficient evidence of patient-to-patient transmission suggests that infection prevention and control measures such as universal surveillance screening and single-room isolation are unlikely to be practical or effective interventions in reducing the overall burden of ESBL-E in hospitals, in line with current European guidelines. Instead, it is argued that efforts should be placed on controlling the spread of these organisms and other MDR-GNB in the community, predominantly long-term care facilities.

Increased Risk for Carbapenem-Resistant Enterobacteriaceae Colonization in Intensive Care Units after Hospitalization in Emergency Department

Carbapenem-resistant Enterobacteriaceae (CRE) colonization is common in hospital patients admitted to intensive care units (ICU) from the emergency department. We evaluated the effect of previous hospitalization in the emergency department on CRE colonization at ICU admission. Our case–control study included 103 cases and 201 controls; cases were patients colonized by CRE at admission to ICU and controls were patients admitted to ICU and not colonized. Risk factors were emergency department stay, use of carbapenem, Simplified Acute Physiology Score, upper digestive endoscopy, and transfer from another hospital. We found that ED stay before ICU admission was associated with CRE colonization at admission to the ICU. Our findings indicate that addressing infection control problems in EDs will help to control carbapenem resistance in ICUs.

Diagnostic performance of the Xpert Carba-R™ assay directly from rectal swabs for active surveillance of carbapenemase-producing organisms in the largest Brazilian University Hospital

BACKGROUND

The global spread of carbapenemase-producing organisms (CPO) has been considered by international health authorities as a critical public health concern. Brazil has a high CPO prevalence according to distinct publications but many routine microbiology laboratories have only phenotypic resources to evaluate this epidemiological situation, which is time-consuming and detects only carbapenem-resistant isolates missing CPO susceptible expressing a slightly decreased susceptibility. New molecular platforms can detect CPO faster but a local evaluation is essential.

AIM

To evaluate the performance of CPO detection direct from rectal swabs with the Xpert Carba-R™ assay (Cepheid, Sunnyvale, CA) in the largest Brazilian University Hospital.

METHODS

A prospective diagnostic accuracy study of CPO was performed with the collection of rectal swabs from patients admitted into the Intensive Care Unit (ICU) and into the Emergency Department (ED) between April and July 2016. The Xpert Carba-R™ assay results were compared with carbapenem-resistant Enterobacterales (CRE) surveillance cultures plus in-house PCR carbapenemase detection (reference method). In case of discordant results between methods, additional tests were performed. The limit of detection (LoD) for the CRE culture and the Xpert Carba-R™ assay were performed with contrived isolates of known carbapenemases genes.

RESULTS

A total of 921 clinical rectal swabs were analyzed being 21% (196/921) from the ICU and 79% (725/921) from the ED. Overall, the Xpert Carba-R™ assay detected 9.9% (91/921) of CPOs being 9.5% (87/921) positive only for bla_KPC and 0.4% (4/921) positive only for bla_NDM. The reference method detected 9.1% (84/921) CPO being 77 (8.4%) bla_KPC, 5 bla_VIM (0.5%) and 2 bla_NDM (0.2%). No IMP or OXA-48 like gene was detected. Overall, twelve samples, 1.3% (10 bla_KPC, 2 bla_NDM) were Xpert Carba-R™ positive but negative by the reference method. Five isolates (0.5%) were positive for bla_VIM only by in-house PCR and confirmed to be bla_VIM-2 by DNA sequencing. The Kappa value, sensitivity, specificity, positive/negative predictive values and accuracy of the Xpert Carba-R™ assay were; 0.893 (95% confidence interval [CI], 0.842-0.944), 94% (86.7-98.0), 98.6% (97.5-99.3), 86.8% (78.1-93.0), 99.4% (98.6-99.8) and 98.2% (97.3-99.1), respectively. The LoD for bla_KPC of the Xpert Carba-R™ assay and the CRE cultures were 10¹ CFU/swab.

CONCLUSION

The Xpert Carba-R™ assay is an accurate test to detect CPO directly from the rectal swabs with significant lower turnaround time (TAT) when compared to the reference method (CRE culture plus in-house PCR). Xpert Carba-R™ may, therefore, be regarded as a good and fast epidemiological tool.

Genomic Analysis of Carbapenemase-Producing Extensively Drug-Resistant Klebsiella pneumoniae Isolates Reveals the Horizontal Spread of p18-43_01 Plasmid Encoding blaNDM-1 in South Africa

Whole-genome sequence (WGS) analyses were employed to investigate the genomic epidemiology of extensively drug-resistant Klebsiella pneumoniae strains, focusing on the carbapenem resistance-encoding determinants, mobile genetic support, clonal and epidemiological relationships. A total of ten isolates were obtained from patients admitted to the intensive care unit (ICU) in a public hospital in South Africa. Five isolates were from rectal swabs of colonized patients and five from blood cultures of patients with invasive carbapenem-resistant infections. Following microbial identification and antibiotic susceptibility tests, the isolates were subjected to WGS on the Illumina MiSeq platform. All the isolates showed genotypic resistance to tested β-lactams (NDM-1, OXA-1, CTX-M-15, TEM-1B, SHV-1) and other antibiotics. All but one isolate belonged to the ST152 with a novel sequence type, ST3136, differing by a single-locus variant. The isolates had the same plasmid multilocus sequence type (IncF[K12:A-:B36]) and capsular serotype (KL149), supporting the epidemiological linkage between the clones. Resistance to carbapenems in the 10 isolates was conferred by the bla_NDM-1 mediated by the acquisition of multi-replicon [ColRNAI, IncFIB(pB171), Col440I, IncFII, IncFIB(K) and IncFII(Yp)] p18-43_01 plasmid. These findings suggest that the acquisition of bla_NDM-1-bearing plasmid structure (p18-43_01), horizontal transfer and clonal dissemination facilitate the spread of carbapenemases in South Africa. This emphasizes the importance of targeted infection control measures to prevent dissemination.

Is Meropenem as a Monotherapy Truly Incompetent for Meropenem-Nonsusceptible Bacterial Strains? A Pharmacokinetic/Pharmacodynamic Modeling With Monte Carlo Simulation

Infections due to meropenem-nonsusceptible bacterial strains (MNBSs) with meropenem minimum inhibitory concentrations (MICs) ≥ 16 mg/L have become an urgent problem. Currently, the optimal treatment strategy for these cases remains uncertain due to some limitations of currently available mono- and combination therapy regimens. Meropenem monotherapy using a high dose of 2 g every 8 h (q 8 h) and a 3-h traditional simple prolonged-infusion (TSPI) has proven to be helpful for the treatment of infections due to MNBSs with MICs of 4–8 mg/L but is limited for cases with higher MICs of ≥16 mg/L. This study demonstrated that optimized two-step-administration therapy (OTAT, i.e., a new administration model of i.v. bolus plus prolonged infusion) for meropenem, even in monotherapy, can resolve this problem and was thus an important approach of suppressing such highly resistant bacterial isolates. Herein, a pharmacokinetic (PK)/pharmacodynamic (PD) modeling with Monte Carlo simulation was performed to calculate the probabilities of target attainment (PTAs) and the cumulative fractions of response (CFRs) provided by dosage regimens and 39 OTAT regimens in five dosing models targeting eight highly resistant bacterial species with meropenem MICs ≥ 16 mg/L, including Acinetobacter baumannii, Acinetobacter spp., Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Stenotrophomonas maltophilia, were designed and evaluated. The data indicated that meropenem monotherapy administered at a high dose of 2 g q 8 h and as an OTAT achieved a PTA of ≥90% for isolates with an MIC of up to 128 mg/L and a CFR of ≥90% for all of the targeted pathogen populations when 50% f T > MIC (50% of the dosing interval during which free drug concentrations remain above the MIC) is chosen as the PD target, with Enterococcus faecalis being the sole exception. Even though 50% f T > 5 × MIC is chosen as the PD target, the aforementioned dosage regimen still reached a PTA of ≥90% for isolates with an MIC of up to 32 mg/L and a CFR of ≥90% for Acinetobacter spp., Pseudomonas aeruginosa, and Klebsiella pneumoniae populations. In conclusion, meropenem monotherapy displays potential competency for infections due to such highly resistant bacterial isolates provided that it is administered as a reasonable OTAT but not as the currently widely recommended TSPI.

Association between carbapenem-resistant Enterobacteriaceae and death: A systematic review and meta-analysis

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) has emerged in health care facilities around the world. Several studies demonstrated data regarding clinical outcomes for CRE infections including death. This systematic review and meta-analysis summarized literature discussing association between CRE and mortality.

METHODS

A systematic literature review was performed by searching EMBASE, International Pharmaceutical Abstract databases, PubMed, and Scopus and to identify studies that assessed the association between CRE and death published from April 2012 to October 2017. A meta-analysis was performed using a random effect model. Heterogeneity was assessed using the I²-statistic.

RESULTS

Twenty-one studies were included in this meta-analysis. The underlying populations were moderately heterogeneous (I² = 60%; P = .01). Pooled risk estimates from 9 studies revealed a significant association between CRE and death (pooled-adjusted odds ratio: 2.85; 95% confidence interval: 1.88, 4.30). The unadjusted variable pooled from 18 studies demonstrated a significant association between CRE and death (pooled-unadjusted odds ratio: 3.73; 95% confidence interval: 2.02, 6.88).

DISCUSSION

The finding that CRE infection was positively associated with death agreed with the previous meta-analysis of studies published before April 2012.

CONCLUSIONS

This meta-analysis found that CRE was associated with increased risk of death. Our analysis implies a need for strict infection control measures.

Fecal carriage and molecular epidemiology of carbapenem-resistant Enterobacteriaceae from outpatient children in Shanghai

Background

Fecal colonization with carbapenem-resistant Enterobacteriaceae (CRE) is a risk factor for bacterial translocation resulting in subsequent endogenous infections. The purpose of this study is to investigate the prevalence of CRE strains colonization in stool samples of outpatient in a tertiary pediatric hospital of Shanghai, China.

Methods

In a retrospective study, fecal samples were consecutively obtained from patients in 2016 and screening test for CRE was conducted by using home-made MacConkey agar. Antimicrobial susceptibility was determined by the broth microdilution method and β-lactamases were characterized by polymerase chain reaction (PCR) assays and DNA sequencing. Multilocus sequence typing (MLST) was performed for the genetic relationships of the isolates.

Results

A total of 880 fecal samples were included for this screening test and 32 CRE strains were identified in 32 non-duplicate fecal samples from 32 children (1.3 ± 1.5 years), with a carriage rate of 3.6%. These strains mainly distributed in Klebsiella pnuemoniae (37.5%) and Escherichia coli (37.5%). All CRE strains showed high resistance to most of the routinely used antibiotics (> 90%) except for polymyxin B and tigecycline. The bla_NDM gene was the major carbapenemase gene harbored by gastrointestinal CRE strains, followed by bla_KPC-2, bla_IMP-26, and bla_IMP-4. Other β-Lactamase genes including bla_CTX-M, bla_SHV, bla_TEM-1, and bla_DHA-1 were also detected. MLST analysis revealed that various sequence types (STs) were detected in these strains, with ST11 and ST37 being more prevalent in K.pneumoniae and ST101 in E.coli.

Conclusions

This study revealed the prevalence of CRE fecal carriage in children from outpatient and urgent implementation of infection control measure should be conducted to limit the spread of CRE strains.

Carrier prevalence and risk factors for colonisation of multiresistant bacteria in Danish emergency departments: a cross-sectional survey

OBJECTIVES

The aim of this study was to describe the carrier prevalence and demographic variation of four different multiresistant bacteria (MRB) among acute patients in Danish emergency departments (EDs): methicillin-resistant Staphylococcus aureus (MRSA), carbapenemase-producing enterobacteria (CPE), extended-spectrum beta-lactamase-producing enterobacteria (ESBL) and vancomycin-resistant enterococci (VRE), and to analyse the association of MRB carriage to a range of potential risk factors.

DESIGN

Multicentre descriptive and analytic cross-sectional survey.

SETTING

Eight EDs and four clinical microbiology departments in Denmark.

PARTICIPANTS

Adults visiting the ED.

MAIN OUTCOME MEASURES

Swabs from nose, throat and rectum were collected and analysed for MRSA, ESBL, VRE and CPE. The primary outcome was the prevalence of MRB carriage, and secondary outcomes relation to risk factors among ED patients.

RESULTS

We included 5117 patients in the study. Median age was 68 years (54-77) and gender was equally distributed. In total, 266 (5.2%, 95% CI 4.6 to 5.8) were colonised with at least one MRB. No significant difference was observed between male and female patients, between age groups and between university and regional hospitals. Only 5 of the 266 patients with MRB were colonised with two of the included bacteria and none with more than two. CPE prevalence was 0.1% (95% CI 0.0 to 0.2), MRSA prevalence was 0.3% (95% CI 0.2 to 0.5), VRE prevalence was 0.4% (95% CI 0.3 to 0.6) and ESBL prevalence was 4.5% (95% CI 3.9 to 5.1). Risk factors for MRB carriage were previous antibiotic treatment, previous hospital stay, having chronic respiratory infections, use of urinary catheter and travel to Asia, Oceania or Africa.

CONCLUSION

Every 20th patient arriving to a Danish ED brings MRB to the hospital. ESBL is the most common MRB in the ED. The main risk factors for MRB carriage are recent antibiotic use and travel abroad.

TRIAL REGISTRATION NUMBER

NCT03352167;Post-results.

Prevalence and Risk Factors of Carbapenem-resistant Enterobacteriaceae Acquisition in an Emergency Intensive Care Unit in a Tertiary Hospital in Korea: a Case-Control Study

BACKGROUND

Infections caused by carbapenem-resistant Enterobacteriaceae (CRE) are associated with high mortality rates and their treatment is difficult because treatment is limited to certain antibiotics, such as colistin and tigecycline. We aimed to perform active surveillance culture of CRE (ASC-CRE) to monitor the prevalence of CRE acquisition during intensive care unit (ICU) care and to examine the potential risk factors associated with CRE acquisition.

METHODS

We conducted ASC-CRE on patients who were admitted to the ICU in the emergency room at a tertiary hospital. Rectal swabs were analyzed using methods established by the Centers for Disease Control and Prevention. To detect carbapenemase-producing CRE, a polymerase chain reaction assay to detect five carbapenemase genes (bla_NDM, bla_KPC, bla_VIM, bla_IMP-1, and bla_OXA-48) was performed.

RESULTS

There were 22 CRE acquisition in 21 patients (2.6%, 21/810) and the incidence of CRE acquisition was 4.3/1,000 person-days, respectively. The most common species detected was Klebsiella pneumoniae (72.7%, 16/22), and 9 carbapenemase-producing CREs (7 bla_KPC and 2 bla_NDM) were detected. Independent risk factors associated with CRE acquisition were men gender (adjusted odds ratio [aOR], 5.3; 95% confidence interval [CI], 1.3-21.3), history of admission within one year (aOR, 3.9; 95% CI, 1.2-12.1), co-colonization with multidrug-resistant Acinetobacter baumannii (aOR, 15.6; 95% CI, 3.6-67.8) and extended-spectrum β-lactamases-producing bacteria (aOR, 4.7; 95% CI, 1.5-14.6), and exposure to glycopeptide antibiotics (aOR, 3.6; 95% CI, 1.3-9.9).

CONCLUSION

The identification of patients with risk factors for CRE acquisition and early detection of CRE acquisition using ASC-CRE may be useful for CRE control.

Simultaneous colonization by Escherichia coli and Klebsiella pneumoniae harboring mcr-1 in Brazil

CASE PRESENTATION

We present a case report of a woman, concurrently colonized by polymyxin-resistant E. coli and K. pneumoniae. A Brazilian female patient, in her mid-fifties, was hospitalized with schistosomiasis. During hospitalization, polymyxin-resistant E. coli and K. pneumoniae were isolated from surveillance cultures.

METHODS

Identification, antimicrobial susceptibility testings, PCR for mcr-1, plasmid transfer by conjugation and whole genome sequencing were performed.

RESULTS

E. coli ST744 and K. pneumoniae ST101 carrying mcr-1 gene were described. Transconjugant E. coli was positive for mcr-1 and IncX4 by PCR. The plasmid is a 33,304-base pair plasmid, and the mcr-1 gene was the only antimicrobial resistance gene present in the plasmid.

CONCLUSIONS

This study presents a case report of a hospitalized woman, concurrently colonized by mcr-1-harboring E. coli ST744, a different ST from previously described in Brazil, and a K. pneumoniae ST101.

Molecular and epidemiological analysis of IMP-1 metallo-β-lactamase-producing Klebsiella pneumoniae in a tertiary care hospital in Japan

This study investigated the molecular and phenotypic characteristics of carbapenemase-producing Klebsiella pneumoniae, and identified the risk factors underlying its acquisition. We evaluated K. pneumoniae isolated in Nagasaki University Hospital between January 2009 and June 2015. The presence of carbapenemase genes and plasmid characteristics were investigated. We performed multilocus sequence typing (MLST), and generated a dendrogram based on the results of pulsed-field gel electrophoresis (PFGE) for carbapenemase-producing strains. We also performed a case-control study of patients. Of the 88 K. pneumoniae strains that showed minimum inhibitory concentration ≥1 μg/mL for imipenem and/or meropenem, and that were available from our bacterial collection, 18 had the IMP-type carbapenemase gene, all of which were IMP-1 according to sequencing analysis. Strains included seven different sequence types (STs), of which the most common was ST1471. A dendrogram showed the significant similarity of some strains with relationships in PFGE patterns, STs, and the wards in which they were isolated. Plasmid incompatibility group was similar among the IMP-1 producers. Regarding risk factors, multivariate analysis showed that liver disease and previous uses of carbapenems and anti-fungal drugs were significant factors for the acquisition of IMP-1-producing strains. Our results demonstrate that IMP-1 is a major carbapenemase produced by K. pneumoniae. The PFGE results indicated the possibility of transmission in the hospital. The identified risk factors should be considered for appropriate antibiotic therapy and infection-control measures.