Extent and Resistance Patterns of Gram-negative Bacteria Isolated From 13 Hospitals in Shaoxing, Zhejiang Province

Gram-negative bacteria are increasingly recognized as the sauce of severe infections. In recent years, epidemiological data has indicated that the drug resistance rate of Gram-negative bacteria has significantly increased. We analyzed the epidemiological surveillance data of gram-negative bacteria in Shaoxing City in 2021 by retrospectively collecting drug susceptibility data of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Burkholderia cepacian from thirteen tertiary hospitals. A total of 24,142 strains were collected from thirteen hospitals. The isolation rates of E. coli, K. pneumoniae, P. aeruginosa, A. baumannii, P. mirabilis, E. cloacae, and B. cepacian were 29.25%, 18.83%, 11.03%, 8.43%, 3.80%, 3.12%, and 0.75%, respectively. Among them, 2.86% were carbapenem-resistant E. coli, 12.98% were CRKP, 31.27% were CRPA, and 34.77% were CRAB. Carbapenem-resistant Enterobacterales were more sensitive to ceftazidime-avibactam and polymyxin. The drug resistance rates of P. aeruginosa and A. baumannii to polymyxin were 0 and 1.3%, but the resistance rates to ceftazidime-avibactam were 10.5% and 26.0%, respectively. Based on results from epidemiological data, CRKP had a high isolation rate and non-fermenting bacteria had a high resistance rate to ceftazidime-avibactam. All hospitals should strengthen monitoring and enact continuous intervention to reduce the generation and spread of drug-resistant bacteria.

Clinical and molecular epidemiology of carbapenem-resistant Enterobacteriaceae in pediatric inpatients in South China

IMPORTANCE

This study assessed the clinical and molecular epidemiology of carbapenem-resistant Enterobacteriaceae in pediatric inpatients at three hospitals in South China by means of screening stool samples for carbapenem-resistant genes and a nested case-control study to determine risk factors for carriage of carbapenem-resistant Enterobacteriaceae. Of 4,033 fecal samples screened, 158 (3.92%) were positive for CRE, including Escherichia coli (51.27 %), Klebsiella pneumoniae (37.97%), and Enterobacter cloacae (6.96%). The most common carbapenemase genes harbored by gastrointestinal CRE strains were blaNDM-5, blaNDM-1, and blaIMP-4. Hematological malignancies, respiratory diseases, otolaryngological diseases, nervous system diseases, oral administration of third-generation cephalosporins, and the combined use of two or more antibiotics were independently associated with CRE colonization.

Mortality rate and factors associated with mortality of carbapenem-resistant Enterobacteriaceae infection

Background:

Carbapenem-resistant Enterobacteriaceae (CRE) is a serious pathogen with high mortality. Recognition of factors associated with mortality and treating these modifiable factors are crucial to reducing mortality.

Objective:

To determine the 30-day mortality and factors associated with a 30-day mortality of CRE infection.

Methods:

A retrospective cohort study was conducted between January 1, 2015, and December 31, 2019. All patients diagnosed with CRE infection aged ≥18 years were included. Multivariate logistic regression was used for evaluating the factors associated with 30-day mortality and presented as adjusted odds ratio (aOR) with 95% confidence interval (CI).

Result:

One hundred and ninety-four patients were enrolled. The 30-day mortality occurred in 75 patients (38.7%). The common antibiotic regimen was monotherapy and combination of carbapenem, colistin, amikacin, tigecycline, and fosfomycin. CRE isolates were susceptible to tigecycline (93.8%), colistin (91.8%), fosfomycin (89.2%), and amikacin (89.2%). The independent factors associated with 30-day mortality were an increasing simplified acute physiology (SAP) II score (aOR 1.11, 95% CI 1.05-1.16, p < 0.001), sepsis at time of CRE infection diagnosis (aOR 7.93, 95% CI 2.21-28.51, p = 0.002), pneumonia (aOR 4.48, 95% CI 1.61-12.44, p = 0.004), monotherapy (aOR 4.69, 95% CI 1.71-12.85, p = 0.003), and improper empiric antibiotic (aOR 5.13, 95% CI 1.83-14.40, p = 0.002).

Conclusion:

The overall 30-day mortality of CRE infection was high. The factors associated with mortality were an increasing SAP II score, sepsis at time of CRE infection diagnosis, pneumonia, monotherapy, and improper empiric antibiotic. The study suggested that proper empiric antibiotic and combination antibiotics might reduce mortality from CRE infection.

Clinical Outcomes and Treatment Strategies in Patients With Non-Carbapenemase-producing Carbapenem-Resistant Versus Carbapenem-Susceptible Enterobacterales Infections

BACKGROUND

Carbapenem-resistant Enterobacterales (CRE) are difficult to treat and can cause significant morbidity and mortality, however most data reflect carbapenemase-producing infections.

OBJECTIVE

Our objective was to evaluate clinical outcomes of non-carbapenemase-producing CRE (nCP-CRE) compared with carbapenem-susceptible Enterobacterales (CSE) infections.

METHODS

This was a retrospective, multicenter, observational study (January 1, 2018 to December 31, 2020). The primary outcome was clinical success at 30 days with secondary outcomes, including clinical success at 90 days, clinical success based on treatment for nCP-CRE, persistent bacteremia, intensive care unit (ICU) admission, length of stay, and rate of Clostridioides difficile or multidrug resistant infections.

RESULTS

The final analysis included 211 patients: 142 (67%) with CSE and 69 (33%) with nCP-CRE infections. Prior carbapenem exposure was more common with nCP-CRE (15% vs 4%, P = 0.01). Clinical success at 30 days was similar between groups (77% vs 74%, P = 0.73). There were no differences in secondary outcomes. There was an overall low use of carbapenems (empiric 6%, definitive 7%). Most nCP-CRE infections were treated with a monotherapy carbapenem-sparing regimen (empiric 88%, definitive 90%). Limitations include the retrospective design and the high rate of urinary infections.

CONCLUSION AND RELEVANCE

Our study found no difference in clinical outcomes between nCP-CRE and CSE infections. Application of this study with future studies would help in determining optimal regimens for these infections.

Active Screening of Intestinal Colonization of Carbapenem-Resistant Enterobacteriaceae for Subsequent Bloodstream Infection in Allogeneic Hematopoietic Stem Cell Transplantation

Purpose

To investigate the prevalence, risk factors of intestinal carbapenem-resistant Enterobacteriaceae (CRE) colonization and bloodstream infection (BSI) caused by CRE in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients.

Methods

We analyzed the clinical data of 185 patients with hematological malignancies who underwent allo-HSCT from May 2019 to December 2021. All patients received regular CRE monitoring by rectal swab during allo-HSCT, and some CRE strains were further identified for carbapenemase phenotypes. The rates, distribution and risk factors of CRE colonization, CRE-induced BSI were analyzed.

Results

CRE was detected in 44 of 185 recipients, with colonization rate of 23.8%. A total of 46 strains of CRE were isolated, including 22 Escherichia coli, 17 Klebsiella pneumoniae, three Klebsiella oxytoca, two Enterobacter hormaechei, and two other Enterobacteriaceae. Among the 19 strains identified with carbapenemase phenotypes, eight strains of E. coli produced metal β-lactamase, five K. pneumoniae produced serine carbapenemase, two K. pneumoniae produced metal β-lactamase, two K. oxytoca produced metal β-lactamase, a Citrobacter malonic acid-free produced metal β-lactamase and a Citrobacter freundii produced metal β-lactamase. In 10 patients developed with CRE-related BSI, the types and combined drug sensitivity of strains detected by rectal swab were highly consistent with blood culture. Multivariate analysis revealed that pulmonary infection, perianal infection and carbapenem application in the 3 months pre-transplant were independent risk factors for rectal CRE colonization, while rectal colonization with carbapenem-resistant K. pneumoniae (CR-KP) was an independent risk factor for CRE-induced BSI. The mortality rate within 30 days of CRE-related BSI was 50.0%, and patients receiving multi-drug therapy within 24 hours showed slightly lower mortality than that in the single-drug treatment group.

Conclusion

Allo-HSCT patients with CRE-induced BSI have poor prognosis, and CR-KP rectal colonization is an independent risk factor for CRE-related BSI. Rectal swab screening during allo-HSCT could provide early warning for later CRE-induced BSI.

Identification and infection control of carbapenem-resistant Enterobacterales in intensive care units

Infections with multidrug-resistant organisms among patients in intensive care units (ICUs) are associated with high mortality. Among multidrug-resistant organisms, carbapenem-resistant Enterobacterales (CRE) harbor important pathogens for healthcare-associated infections, including pneumonia, bacteremia, and urinary tract infections. Risk factors for CRE colonization include underlying comorbid conditions, prior antibiotics exposure, prior use of healthcare facilities, device use, and longer ICU stay. The mortality rate due to invasive CRE infection is 22%–49%, and CRE colonization is associated with an approximately 10-fold increased risk of CRE infection. Infection control measures include hand hygiene, contact precautions, minimizing the use of devices, and environmental control. Additionally, implementing active surveillance of CRE carriage should be considered in ICU settings.

Pyrazole-Thiazole Core-Containing Analogs Exhibit Adjunctive Activity with Meropenem against Carbapenem-Resistant Enterobacteriaceae (CRE)

Pyrazole-thiazole core-containing compound KP-40 and 20 novel derivatives were designed and synthesized through traditional SAR analysis. These molecules displayed adjunctive activity with meropenem against Gram-negative bacteria evidenced by a range of fractional inhibitory concentration (FIC=0.5-0.25) and minimum adjunctive concentration (MAC=128-32 μM) values. Of this series of molecules, four compounds displayed notable adjunctive potential, with FIC and MAC values of 0.25 and 32 μM, respectively. Moreover, the solubility of these compounds was improved to an acceptable range. Further analysis using our "in house" permeation and efflux multi parameter optimization (PEMPO) algorithm revealed key physicochemical properties that may be critical for the development of active Gram-negative antibacterials. Taking PEMPO scores into consideration prior to executing synthesis of analogs may be a simple, yet rapid and effective strategy that can be used in conjunction with traditional SAR approaches to aid in the design of potent Gram-negative antibacterials.

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

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

Nanopore MinION Sequencing Reveals Possible Transfer of bla KPC-2 Plasmid Across Bacterial Species in Two Healthcare Facilities

Carbapenemase-producing Enterobacteriaceae are a major threat to global public health. Klebsiella pneumoniae carbapenemase (KPC) is the most commonly identified carbapenemase in the United States and is frequently found on mobile genetic elements including plasmids, which can be horizontally transmitted between bacteria of the same or different species. Here we describe the results of an epidemiological investigation of KPC-producing bacteria at two healthcare facilities. Using a combination of short-read and long-read whole-genome sequencing, we identified an identical 44 kilobase plasmid carrying the bla KPC-2 gene in four bacterial isolates belonging to three different species (Citrobacter freundii, Klebsiella pneumoniae, and Escherichia coli). The isolates in this investigation were collected from patients who were epidemiologically linked in a region in which KPC was uncommon, suggesting that the antibiotic resistance plasmid was transmitted between these bacterial species. This investigation highlights the importance of long-read sequencing in investigating the relatedness of bacterial plasmids, and in elucidating potential plasmid-mediated outbreaks caused by antibiotic resistant bacteria.

Successful Treatment of Serious Meningitis Caused by Extremely Carbapenem-Resistant Enterobacter cloacae (MIC≥16mg/L) with i.v. Meropenem and i.v. Amikacin Plus Intraventricular Amikacin

Background

Carbapenem-resistant Enterobacteriaceae (CRE) meningitis are associated with poor outcomes and high mortality. Here, we report the first successful treatment case of serious meningitis caused by extremely carbapenem-resistant Enterobacter cloacae (minimum inhibitory concentration (MIC) of imipenem ≥16mg/L) with high-dose prolonged infusion of meropenem and i.v. amikacin plus intraventricular (IVT) amikacin.

Case presentation

A 17-year-old girl developed meningitis from an extremely carbapenem-resistant Enterobacter cloacae (MIC of imipenem ≥16mg/L) as a complication of the removal of a giant central neurocytoma located in bilateral and third ventricles. The patient received four surgeries (one tumor excision and three external ventricular drainages) and was treated with a 70 days course of antibiotics therapy during 100 days hospitalization. Finally, she was safely and successfully treated with the high-dose prolonged infusion of meropenem and i.v. amikacin plus IVT amikacin.

Conclusion

This case report shows the possibility of the antibiotic regimen of high-dose prolonged infusion of meropenem and i.v. amikacin plus IVT amikacin in the successful treatment of CRE meningitis (MIC of imipenem ≥16mg/L) especially when other antibiotics are unavailable or restricted.

Duodenoscope-Associated Infections beyond the Elevator Channel: Alternative Causes for Difficult Reprocessing

OBJECTIVES

Duodenoscopes have been widely used for both diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP) procedures, but recently, numerous outbreaks of multidrug-resistant organisms (MDRO) infections have been reported which has led to extensive research for their possible causes. Consequently, the aim of this study is to search for possible duodenoscope surface damages that could provide an alternative and plausible source of infections.

MATERIALS AND METHODS

In order to assess both outer and inner surfaces, a duodenoscope was dismantled and samples were taken from the outer resin polymer and from the air/water, elevator, and working (biopsy) channels that were characterized by FTIR, DSC, TGA, AFM, SEM techniques and the antimicrobial activity were tested.

RESULTS

Alterations were noticed on both the coating and working channel polymers, with external alterations increasing progressively from the proximal sample to the distal sample near the tip of the scope. However, the results showed that the coating surface was still efficient against bacterial adhesion. Changes in surface texture and also morphological changes were shown.

CONCLUSIONS

The study describes the impact of routine procedural use and reprocessing cycles on the duodenoscope, showing that these may possibly make it susceptible to bacterial contamination and MDRO biofilm formation due to difficult reprocessing of the altered surfaces.

Rectal Carriage of Carbapenem-Resistant Enterobacteriaceae: A Menace to Highly Vulnerable Patients

Background:

Bloodstream infection (BSI) due to carbapenem-resistant enterobacteriaceae (CRE) is the leading cause of morbidity and mortality in patients with hematological malignancy. These patients receive chemotherapy during treatment, which lead to severe mucositis of gastrointestinal tract and myelosuppression. It was hypothesized that the gut colonizer translocate into the blood circulation causing BSI. Colonization rate with CRE among these patients in India is unknown.

Aim:

This study aims to determine the carriage rate of CRE in cancer patients.

Setting and Design:

A prospective study was conducted in a tertiary care hospital of India.

Materials and Methods:

Rectal swab of 93 patients were collected and processed as per the Center for Disease Control and Prevention protocol for detection of CRE. The isolate CREs were identified by standard phenotypic tests and confirmed for carbapenem resistance by disk diffusion test using carbapenem disk (imipenem, meropenem, doripenem, and ertapenem), Carba-NP test and modified Hodge test. Resistant to any of the carbapenem disc is considered as CRE.

Results:

A total of 86 isolates were detected from 93 patients. Seventy-six isolates were identified as CRE, and 10 isolates were Gram-positive cocci and other Gram-negative bacilli. Acute myeloid leukemia was the most common clinical presentation followed by acute lymphoid leukemia. Thirty-nine out of 93 patients were on chemotherapy. Sixty-seven out of 76 isolates of CRE were observed positive for carbapenemase production by Carba-NP test.

Conclusion:

This study highlights very high rate of CRE carriage among the hematological malignancy patients; who are highly vulnerable to infection. This confirms the need of infection control prevention activities among the hematological malignancy patients.

Carbapenemase-Producing Organisms: A Global Scourge

The dramatic increase in the prevalence and clinical impact of infections caused by bacteria producing carbapenemases is a global health concern. Carbapenemase production is especially problematic when encountered in members of the family Enterobacteriaceae. Due to their ability to readily spread and colonize patients in healthcare environments, preventing the transmission of these organisms is a major public health initiative and coordinated international effort are needed. Central to the treatment and control of carbapenemase-producing organisms (CPOs) are phenotypic (growth-/biochemical-dependent) and nucleic acid-based carbapenemase detection tests that identify carbapenemase activity directly or their associated molecular determinants. Importantly, bacterial isolates harboring carbapenemases are often resistant to multiple antibiotic classes, resulting in limited therapy options. Emerging agents, novel antibiotic combinations and treatment regimens offer promise for management of these infections. This review highlights our current understanding of CPOs with emphasis on their epidemiology, detection, treatment, and control.

Mechanism for carbapenem resistance of clinical Enterobacteriaceae isolates

Carbapenemase-producing 'super bacteria', particularly NDM-1 and its variants, have become a major public health concern worldwide. The present study aimed to explore the molecular mechanism for carbapenem resistance of clinical Enterobacteriaceae isolates. Seventy-eight non-repeated Enterobacteriaceae strains resistant to any carbapenem were screened at the First Affiliated Hospital of Zhengzhou University (Zhengzhou, China) between December 2011 and December 2015. Outer membrane porin (OMP) proteins were detected using SDS-PAGE. Carbapenemases, extended-spectrum β-lactamases (ESBLs) and plasmid AmpC enzyme genes were detected using polymerase chain reaction (PCR). PCR and SDS-PAGE demonstrated that 60.3% (47/78) of the strains produced carbapenemases, of which 33.3% (26/78) produced KPC-2 carbapenemase, suggesting that the strains resisted carbapenems primarily through carbapenemases. SDS-PAGE showed that the OMP proteins in the majority of carbapenem-resistant Enterobacteriaceae (CRE) strains were deleted or decreased compared with those in the sensitive strains. Of the 44 Klebsiella strains, 59.1% (26/44) did not express or expressed less OmpK35 or OmpK36. Among the 34 strains of other enterobacteria, 97.1% (33/34) did not express or expressed less OmpC or OmpF. Of all CRE strains, 35.9% (28/78) lost at least one OMP protein, indicating that the strains resisted carbapenems also by producing ESBLs and/or plasmid AmpC enzyme, as well as by losing OMP proteins. The resistance of clinically isolated CRE strains may primarily be attributed to the production of carbapenemases, and may also involve the deletion of OMP proteins or mutation of OMP genes.

The emerging threat from carbapenem-resistant enterobacteriaceae

The emergence of carbapenem-resistant enterobacteriaceae (CRE) in the United States represents a serious danger to people who are hospitalized and is associated with case mortality rates as high as 50 percent. CRE infections have limited treatment options and the potential to spread widely if prevention and transmission measures are not employed. Decreasing the impact of CRE requires coordinated efforts between nurses and other clinicians, as well as administrators, to improve patient outcomes.

Managing transmission of carbapenem-resistant enterobacteriaceae in healthcare settings: a view from the trenches

In 2011, the National Institutes of Health Clinical Center experienced a cluster of infection and colonization caused by carbapenem-resistant Klebsiella pneumoniae among profoundly immunocompromised inpatients. This manuscript describes the approach and interventions that were implemented in an attempt to curtail the cluster. Interventions employed included engagement of all stakeholders involved in care of at-risk patients; detailed and frequent communication with hospital staff about issues relating to the outbreak; aggressive microbial surveillance; use of techniques that facilitate rapid identification of resistant organisms; rapid characterization of resistance mechanisms; whole-genome sequencing of outbreak isolates to characterize the spread and to investigate mechanisms of healthcare-associated spread; implementation of enhanced contact precautions for all infected or colonized patients; geographic and personnel cohorting; daily chlorhexidine gluconate baths; dedicating equipment to be used solely for cohorted patients and aggressive decontamination of equipment that had to be reused on uncohorted patients; monitoring adherence to infection control precautions, including unwavering attention to adherence to appropriate hand hygiene procedures; and attention to the details of environmental decontamination. In addition, the manuscript discusses some of the challenges associated with managing such an event, as well as a few of the unanticipated consequences associated with the aftermath of the case cluster.