Molecular characterization and risk factors for carbapenem-resistant Gram-negative bacilli colonization in children: emergence of NDM-producing Acinetobacter baumannii in a newborn intensive care unit in Turkey

Molecular epidemiology of carbapenemase encoding genes in A. baumannii-calcoaceticus complex infections in children: a systematic review

Background

Acinetobacter baumannii-calcoaeticus complex is the leader pathogen for the World Health Organization's list due to the escalating prevalence of multidrug-resistant strains. Insights into the molecular characterization of carbapenemase genes in A. baumannii-calcoaceticus complex infections among children are scarce. To address this gap, we conducted a systematic review to describe the molecular epidemiology of the carbapenemase genes in A. baumannii-calcoaceticus complex infections in the pediatric population.

Methods

Adhering to the PRISMA 2020 guidelines for reporting systematic reviews, we conducted a review of in chore bibliographic databases published in English and Spanish, between January 2020 and December 2022. All studies conducted in patients ≤6 years with molecular characterization of carbapenemase-encoding genes in A. baumannii-calcoaceticus infections were included.

Results

In total, 1129 cases were reviewed, with an overall carbapenem-resistance rate of 60.3%. A. baumannii-calcoaceticus was isolated from blood cultures in 66.6% of cases. Regionally, the Eastern Mediterranean exhibited the highest prevalence of carbapenem resistance (88.3%). Regarding the carbapenemase genes, blaKPC displayed an overall prevalence of 1.2%, while class B blaNDM had a prevalence of 10.9%. Class D blaOXA-23-like reported a prevalence of 64%, blaOXA-48 and blaOXA-40 had a prevalence of 33% and 18.1%, respectively. Notably, the Americas region showed a prevalence of blaOXA-23-like at 91.6%.

Conclusion

Our work highlights the high prevalence of carbapenem-resistant A. baumannii-calcoaceticus and class D carbapenemase genes in children. Of note the distribution of different carbapenemase genes reveals considerable variations across WHO regions. To enhance epidemiological understanding, further extensive studies in children are imperative.

Epidemiology of carbapenem-resistant Acinetobacter baumannii colonization in neonatal intensive care units: A systematic review and meta-analysis

BACKGROUND

The rising prevalence of carbapenem-resistant Acinetobacter baumannii (CRAB) in neonatal intensive care units (NICUs) represents an escalating challenge in healthcare settings, particularly in managing hospital-acquired infections (HAIs). Studies across various World Health Organization regions have documented a significant incidence of CRAB-related HAIs, with rates as high as 41.7 cases per 1000 patients in ICUs, accounting for 13.6% of all HAIs. These infections pose a doubled mortality risk compared to infections with carbapenem-susceptible Acinetobacter baumannii. A particularly concerning aspect of CRAB colonization is its asymptomatic nature, enabling its transmission through healthcare workers (HCWs) or the NICU environment to vulnerable neonates with developing immune systems.

AIM

To explore the prevalence of CRAB colonization in NICUs, focusing on neonates, healthcare workers, and the environmental samples, to enhance epidemiological understanding and inform targeted interventions.

METHODS

We conducted according to PRISMA 2020 checklist guidelines, a comprehensive literature search across multiple databases including MEDLINE (Ovid), EMBASE (Ovid), Global Health (Ovid), Web of Science, and Global Index Medicus. Studies were selected based on predetermined criteria, primarily involving neonates, HCWs, and environmental swabs, using culture or molecular methods to detect CRAB colonization. We excluded studies that did not specifically focus on NICUs, were duplicates, or lacked necessary data. The study selection and quality assessment were conducted independently by two reviewers. Data extraction involved collecting comprehensive details about each study. Our statistical analysis used a random-effects model to calculate the pooled prevalence and confidence intervals, stratifying results by regional location. We assessed study heterogeneity using Cochran's Q statistic and I² statistic, with regression tests employed to evaluate potential publication bias.

RESULTS

We analyzed 737 records from five databases, ultimately including 13 studies from ten countries. For neonates, the pooled prevalence was 4.8% (95%CI: 1.1% to 10.5%) with the highest rates observed in South-East Asia (10.5%; 95%CI: 2.4% to 23.3%). Among HCWs, a single Indian study reported a 3.3% prevalence. Environmental samples showed a prevalence of 2.3% (95%CI: 0% to 9.3%), with the highest rates in South-East Asia (10%; 95%CI: 4.2% to 17.7%). Significant heterogeneity was found across studies, and no publication bias was detected.

CONCLUSION

This systematic review highlights a significant prevalence of CRAB colonization in neonates across various regions, particularly in South-East Asia, contrasting with lower rates in high-income countries. The study reveals a gap in research on HCWs colonization, with only a single study from India reporting moderate prevalence. Environmental samples indicate moderate levels of CRAB contamination, again higher in South-East Asia. These findings underscore the need for more extensive and focused research on CRAB colonization in NICUs, including exploring the roles of HCWs and the environment in transmission, understanding antimicrobial resistance patterns, and developing effective prevention measures.

Contamination of healthcare environment by carbapenem-resistant Acinetobacter baumannii

Acinetobacter baumannii is frequently found on floors, devices, and environmental sites in hospitals and can survive for prolonged periods and accumulate resistance determinants. The infection and presence of carbapenem-resistant A. baumannii (CRAB) in patients is associated with increased mortality, severe clinical outcomes, and longer lengths of stay at hospitals. This review addresses contamination by CRAB in corporal surfaces of patients and healthcare workers and environmental sites at healthcare-related settings. We summarized published data during the last decade on potential reservoirs for CRAB, including contamination frequency and the involved resistance mechanisms, and some measures associated with the elimination of CRAB from hospital surfaces.

Detection and characterization of carbapenem resistant Gram-negative bacilli isolates recovered from hospitalized patients at Soba University Hospital, Sudan

Background

Antimicrobial resistance (AMR) poses a complex threat to global health security and universal health coverage. Recently, nosocomial infections with carbapenemase-producing Gram-negative bacilli (GNB) is increasing worldwide. We report the molecular characterization and detection of genes associated with carbapenemase producing Gram negative bacteria isolated from hospitalized patients at Soba University Hospital (SUH) in Khartoum State, Sudan.

Results

Between October 2016 and February 2017, a total of 206 GNB clinical specimens were collected from hospitalized patients in SUH. Of 206 carbapenem resistance isolates, 171 (83 %) were confirmed as phenotypically resistant and 121 (58.7 %) isolates harboured one or more carbapenemase genes. New Delhi metallo-β-lactamase (NDM) types were the most predominant genes, blaNDM 107(52 %), followed by blaIMP 7 (3.4 %), blaOXA-48 5(2.4 %) and blaVIM 2 (0.9 %). Co-resistance genes with NDM producing GNB were detected in 87 (81.3 %) of all blaNDM producing isolates. NDM-1 was the most frequent subtype observed in 75 (70 %) blaNDM producing isolates. The highest percentage of resistance was recorded in ampicillin (98 %), cephalexin (93.5 %) amoxicillin clavulanic acid (90 %), cefotaxime (89.7 %), ceftriaxone (88.4 %), ceftazidime (84.2 %), sulfamethoxazole-trimethoprim (78.4 %) and nitrofurantoin (75.2 %), aztreonam (66 %) and temocillin (64 %). A close correlation between phenotypic and carbapenemase genes detection in all GNB was observed.

Conclusions

The frequency of carbapenemase producing bacilli was found to be high in SUH. NDM was found to be the most prevalent carbapenemase gene among clinical isolates. Close surveillance across all hospitals in Sudan is required. The relative distribution of carbapenemase genes among GNB in nosocomial infections in Africa needs to be defined.

The present danger of New Delhi metallo-β-lactamase: a threat to public health

The evolution of antimicrobial-resistant Gram-negative pathogens is a substantial menace to public health sectors, notably in developing countries because of the scarcity of healthcare facilities. New Delhi metallo-β-lactamase (NDM) is a potent β-lactam enzyme able to hydrolyze several available antibiotics. NDM was identified from the clinical isolates of Klebsiella pneumoniae and Escherichia coli from a Swedish patient in New Delhi, India. This enzyme horizontally passed on to various Gram-negative bacteria developing resistance against a variety of antibiotics which cause treatment crucial. These bacteria increase fatality rates and play an integral role in the economic burden. The efficient management of NDM-producing isolates requires the coordination between each healthcare setting in a region. In this review, we present the prevalence of NDM in children, fatality and the economic burden of resistant bacteria, the clonal spread of NDM harboring bacteria and modern techniques for the detection of NDM producing pathogens.

High intermittent colonization by diverse clones of β-lactam-resistant Gram-negative bacilli suggests an excessive antibiotic use and different sources of transmission in haemodialysis patients

BACKGROUND

The spread of β-lactam-resistant Gram-negative bacilli (GNB) is a topic of worldwide concern; however, knowledge about colonization by these bacteria in haemodialysis patients is limited.

AIM

To analyse the dynamics and factors associated with colonization by β-lactam-resistant GNB in a dialysis centre.

METHODS

A longitudinal study was conducted. Stool samples were collected for each patient to evaluate extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing Gram-negative bacilli. Colonization screens were performed at three time-points and then classified as absent, intermittent, or persistent. Molecular typing included enterobacterial repetitive intergenic consensus (ERIC)-polymerase chain reaction, pulsed-field gel electrophoresis (PFGE), and multi-locus sequence typing (MLST). Clinical information was obtained from medical records and personal interview. A generalized estimating equations model was performed to determinate factors associated with the colonization.

FINDINGS

A total of 210 patients were included. ESBL-producing and carbapenem-resistant GNB colonization reached 41.2% and 11.5%, respectively. Most patients were intermittent carriers with frequencies of 73.9% and 92.95% for each bacteria group. The most frequent ESBL was CTX-M-G1, while the most common carbapenemase was KPC. ERIC-PCR and PFGE revealed high genetic diversity among strains and the Escherichia coli clone ST131 was the most important by MLST. Fluoroquinolone use (odds ratio: 3.13; 95% confidence interval: 1.03-9.44; P [cap] = 0.043) and chronic obstructive lung disease (odds ratio: 3.53; 1.42-8.74; P = 0.006) were associated with ESBL-producing GNB colonization.

CONCLUSION

Our findings indicate a high intermittent colonization by diverse clones of β-lactam-resistant GNB in haemodialysis patients. It suggests excessive antibiotic pressure that favours the acquisition of bacteria with diverse genetic profiles and different transmission sources.

Colonisation with extended spectrum beta-lactamase-producing and carbapenem-resistant Enterobacterales in children admitted to a paediatric referral hospital in South Africa

INTRODUCTION

There are few studies describing colonisation with extended spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and carbapenem-resistant Enterobacterales (CRE) among children in sub-Saharan Africa. Colonisation often precedes infection and multi-drug-resistant Enterobacterales are important causes of invasive infection.

METHODS

In this prospective cross-sectional study, conducted between April and June 2017, 200 children in a tertiary academic hospital were screened by rectal swab for EBSL-PE and CRE. The resistance-conferring genes were identified using polymerase chain reaction technology. Risk factors for colonisation were also evaluated.

RESULTS

Overall, 48% (96/200) of the children were colonised with at least one ESBL-PE, 8.3% (8/96) of these with 2 ESBL-PE, and one other child was colonised with a CRE (0.5% (1/200)). Common colonising ESBL-PE were Klebsiella pneumoniae (62.5%, 65/104) and Escherichia coli (34.6%, 36/104). The most frequent ESBL-conferring gene was blaCTX-M in 95% (76/80) of the isolates. No resistance- conferring gene was identified in the CRE isolate (Enterobacter cloacae). Most of the Klebsiella pneumoniae isolates were susceptible to piperacillin/tazobactam (86.2%) and amikacin (63.9%). Similarly, 94.4% and 97.2% of the Escherichia coli isolates were susceptible to piperacillin/tazobactam and amikacin, respectively. Hospitalisation for more than 7 days before study enrolment was associated with ESBL-PE colonisation.

CONCLUSION

Approximately half of the hospitalised children in this study were colonised with ESBL-PE. This highlights the need for improved infection prevention and control practices to limit the dissemination of these microorganisms.

Risk factor for intestinal carriage of carbapenem-resistant Acinetobacter baumannii and the impact on subsequent infection among patients in an intensive care unit: an observational study

OBJECTIVES

To assess the incidence and the impact of carbapenem-resistant Acinetobacter baumannii (CRAB) intestinal carriage on subsequent CRAB infection and to study risk factors of acquiring CRAB intestinal carriage among patients in intensive care unit (ICU).

DESIGN

Observational study including a case-control study and a retrospective cohort study.

SETTING

A 50-bed general ICU of a university hospital, China.

METHODS

From May 2017 to April 2018, an observational study was conducted in a 50-bed general ICU of a university hospital in China. Rectal swabs were collected from ICU patients on admission and thereafter weekly. A case-control study was performed to analyse risk factors of the acquisition of CRAB intestinal carriage in ICU using multiple logistic regression. A retrospective cohort study was performed to address whether intestinal CRAB carriage could lead to an increased likelihood of subsequent CRAB infection using subdistribution hazard model regarding death in the ICU as a competing risk event.

RESULTS

CRAB intestinal carriage was detected in 6.87% (66/961; 95% CI 5.27% to 8.47%) of patients on ICU admission, whereas 11.97% (115/961; 95% CI 9.91% to 14.02%) of patients acquired CRAB intestinal carriage during the ICU stay. Pancreatitis (OR 2.16, 95% CI 1.28 to 3.67), haematological disease (OR 2.26, 95% CI 1.42 to 3.58), gastric tube feeding (OR 3.35, 95% CI 2.03 to 5.51) and use of carbapenems (OR 1.84, 95% CI 1.11 to 3.07) were independent risk factors for acquiring CRAB intestinal carriage. The incidence of subsequent CRAB infection was 2.24-fold in patients with CRAB intestinal carriage compared with that in patients without (95% CI 1.48 to 3.39, p<0.001).

CONCLUSION

More patients acquired CRAB intestinal carriage during their ICU stay than had on admission. Severity of illness, acute pancreatitis, tube feeding and use of carbapenems were independent risk factors of acquisition of CRAB intestinal carriage. Patients with CRAB intestinal carriage are more likely to develop CRAB infection.

Epidemic Characteristics of Carbapenem-Resistant Klebsiella pneumoniae in the Pediatric Intensive Care Unit of Yanbian University Hospital, China

Introduction

Carbapenem-resistant Enterobacteriaceae (CRE) pose a serious threat to clinical patient management and public health, as they are generally resistant to most antibiotics and cause infections with high mortality rates. Klebsiella pneumoniae ranks second among Enterobacteriaceae species that cause nosocomial infections. In this study, we investigated the epidemic characteristics of carbapenem-resistant K. pneumoniae (CRKP) in the pediatric intensive care unit (PICU) of Yanbian University Hospital.

Materials and Methods

A total of 14 non-duplicate CRKP strains, collected from March 2015 to November 2019, were subjected to automated microbial identification and antimicrobial susceptibility tests using the Phoenix-100 ID/AST system. The strains were also subjected to genotypic resistance testing, polymerase chain reaction assays to detect genes encoding carbapenemases and other β-lactamases, multi-locus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE)-based homology analysis.

Results

Two carbapenemase genes, KPC-2 and NDM-1 (in eight and six strains, respectively), were detected. MLST enabled the division of the strains into two sequence types, ST11 and ST1224 (containing eight and six strains, respectively). PFGE results classified the 14 strains into clonotypes A–D, of which clonotypes A and B belonged to ST11, while clonotypes C and D belonged to ST1224.

Conclusion

Our study reveals that epidemics of the KPC-2-ST11 and NDM-1-ST1224 strains occurred in the PICU of Yanbian University Hospital. Surveillance and strict implementation of prevention and control measures are crucial to prevent the occurrence and rapid spread of nosocomial infections.

Molecular epidemiology of antimicrobial resistant microorganisms in the 21th century: a review of the literature

Healthcare-associated infections (HAIs) are the most frequent and severe complication acquired in healthcare settings with high impact in terms of morbidity, mortality and costs. Many bacteria could be implicated in these infections, but, expecially multidrug resistance bacteria could play an important role. Many microbial typing technologies have been developed until to the the bacterial whole-genome sequencing and the choice of a molecular typing method therefore will depend on the skill level and resources of the laboratory and the aim and scale of the investigation. In several studies the molecular investigation of pathogens involved in HAIs was performed with many microorganisms identified as causative agents such as Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Clostridium difficile, Acinetobacter spp., Enterobacter spp., Enterococcus spp., Staphylococcus aureus and several more minor species. Here, we will describe the most and least frequently reported clonal complex, sequence types and ribotypes with their worldwide geographic distribution for the most important species involved in HAIs.

Meropenem vs standard of care for treatment of neonatal late onset sepsis (NeoMero1): A randomised controlled trial

Background

The early use of broad-spectrum antibiotics remains the cornerstone for the treatment of neonatal late onset sepsis (LOS). However, which antibiotics should be used is still debatable, as relevant studies were conducted more than 20 years ago, recruited in single centres or countries, evaluated antibiotics not in clinical use anymore and had variable inclusion/exclusion criteria and outcome measures. Moreover, antibiotic-resistant bacteria have become a major problem in many countries worldwide. We hypothesized that efficacy of meropenem as a broad-spectrum antibiotic is superior to standard of care regimens (SOC) in empiric treatment of LOS and aimed to compare meropenem to SOC in infants aged <90 days with LOS.

Methods and findings

NeoMero-1 was a randomized, open-label, phase III superiority trial conducted in 18 neonatal units in 6 countries. Infants with post-menstrual age (PMA) of ≤44 weeks with positive blood culture and one, or those with negative culture and at least with two predefined clinical and laboratory signs suggestive of LOS, or those with PMA >44 weeks meeting the Goldstein criteria of sepsis, were randomized in a 1:1 ratio to receive meropenem or one of the two SOC regimens (ampicillin+gentamicin or cefotaxime+gentamicin) chosen by each site prior to the start of the study for 8–14 days. The primary outcome was treatment success (survival, no modification of allocated therapy, resolution/improvement of clinical and laboratory markers, no need of additional antibiotics and presumed/confirmed eradication of pathogens) at test-of-cure visit (TOC) in full analysis set. Stool samples were tested at baseline and Day 28 for meropenem-resistant Gram-negative organisms (CRGNO). The primary analysis was performed in all randomised patients and in patients with culture confirmed LOS. Proportions of participants with successful outcome were compared by using a logistic regression model adjusted for the stratification factors. From September 3, 2012 to November 30th 2014, total of 136 patients (instead of planned 275) in each arm were randomized; 140 (52%) were culture positive. Successful outcome at TOC was achieved in 44/136 (32%) in the meropenem arm vs. 31/135 (23%) in the SOC arm (p = 0.087). The respective numbers in patients with positive cultures were 17/63 (27%) vs. 10/77 (13%) (p = 0.022). The main reason of failure was modification of allocated therapy. Treatment emergent adverse events occurred in 72% and serious adverse events in 17% of patients, the Day 28 mortality was 6%. Cumulative acquisition of CRGNO by Day 28 occurred in 4% of patients in the meropenem and 12% in the SOC arm (p = 0.052).

Conclusions

Within this study population, we found no evidence that meropenem was superior to SOC in terms of success at TOC, short term hearing disturbances, safety or mortality were similar in both treatment arms but the study was underpowered to detect the planned effect. Meropenem treatment did not select for colonization with CRGNOs. We suggest that meropenem as broad-spectrum antibiotic should be reserved for neonates who are more likely to have Gram-negative LOS, especially in NICUs where microorganisms producing extended spectrum- and AmpC type beta-lactamases are circulating.

Extensively-drug resistant Acinetobacter baumannii bacteremia in neonates: effective treatment with the combination of colistin and ampicillin/sulbactam

Acinetobacter baumannii has evolved as a major pathogen of outbreaks in the healthcare setting with increased morbidity and mortality. In neonates, treatment can be quite challenging due to the resistance profile of A. baumannii as well as limited data on pharmakokinetics and pharmakodynamics of antibiotics in this age group. We present an outbreak of eight cases of extensively-drug resistant (XDR) A. baumannii bacteremias successfully managed with the combination of colistin with high dose ampicillin/sulbactam.

Understanding the Epidemiology of Multi-Drug Resistant Gram-Negative Bacilli in the Middle East Using a One Health Approach

In the last decade, extended-spectrum cephalosporin and carbapenem resistant Gram-negative bacilli (GNB) have been extensively reported in the literature as being disseminated in humans but also in animals and the environment. These resistant organisms often cause treatment challenges due to their wide spectrum of antibiotic resistance. With the emergence of colistin resistance in animals and its subsequent detection in humans, the situation has worsened. Several studies reported the transmission of resistant organisms from animals to humans. Studies from the middle east highlight the spread of resistant organisms in hospitals and to a lesser extent in livestock and the environment. In view of the recent socio-economical conflicts that these countries are facing in addition to the constant population mobilization; we attempt in this review to highlight the gaps of the prevalence of resistance, antibiotic consumption reports, infection control measures and other risk factors contributing in particular to the spread of resistance in these countries. In hospitals, carbapenemases producers appear to be dominant. In contrast, extended spectrum beta lactamases (ESBL) and colistin resistance are becoming a serious problem in animals. This is mainly due to the continuous use of colistin in veterinary medicine even though it is now abandoned in the human sphere. In the environment, despite the small number of reports, ESBL and carbapenemases producers were both detected. This highlights the importance of the latter as a bridge between humans and animals in the transmission chain. In this review, we note that in the majority of the Middle Eastern area, little is known about the level of antibiotic consumption especially in the community and animal farms. Furthermore, some countries are currently facing issues with immigrants, poverty and poor living conditions which has been imposed by the civil war crisis. This all greatly facilitates the dissemination of resistance in all environments. In the one health concept, this work re-emphasizes the need to have global intervention measures to avoid dissemination of antibiotic resistance in humans, animals and the environment in Middle Eastern countries.

Prior antibiotic use and acquisition of multidrug-resistant organisms in hospitalized children: A systematic review

Objective:

Multidrug-resistant organisms (MDROs) cause ~5%–10% of infections in hospitalized children, leading to an increased risk of death, prolonged hospitalization, and additional costs. Antibiotic exposure is considered a driving factor of MDRO acquisition; however, consensus regarding the impact of antibiotic factors, especially in children, is lacking. We conducted a systematic review to examine the relationship between antibiotic use and subsequent healthcare-associated infection or colonization with an MDRO in children.

Design:

Systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline.

Methods:

We searched PubMed and Embase for all English, peer-reviewed original research studies published before September 2018. Included studies evaluated hospitalized children, antibiotic use as an exposure, and bacterial MDRO as an outcome.

Results:

Of the 535 studies initially identified, 29 met the inclusion criteria. Overall, a positive association was identified in most studies evaluating a specific antibiotic exposure (17 of 21, 81%), duration of antibiotics (9 of 12, 75%), and number of antibiotics received (2 of 3, 67%). Those studies that evaluated any antibiotic exposure had mixed results (5 of 10, 50%). Study sites, populations, and definitions of antibiotic use and MDROs varied widely.

Conclusions:

Published studies evaluating this relationship are limited and are of mixed quality. Limitations include observation bias in recall of antibiotic exposure, variations in case definitions, and lack of evaluation of antibiotic dosing and appropriateness. Additional studies exploring the impact of antibiotic use and MDRO acquisition may be needed to develop effective antibiotic stewardship programs for hospitalized children.

The impact of paediatric antimicrobial stewardship programmes on patient outcomes

PURPOSE OF REVIEW

Although there has been an unprecedented global effort to reduce the spread of antimicrobial resistance, little emphasis has been placed on children. This review aims to evaluate the impact of paediatric antimicrobial stewardship programmes as well as providing a practical approach for effectively implementing them in community-based settings and in hospitals.

RECENT FINDINGS

Although rates of serious bacterial infection are low in children, the rates of antimicrobial use and resistance are comparable with adults. Different strategies are required to implement antimicrobial stewardship in community-based settings compared to in hospitals. Nationally coordinated, whole-system approaches have achieved long-term, sustainable reductions in antimicrobial prescribing, as well as reductions in resistance rates at population level, with no evidence of an increase in rate of serious infection or bacterial complications.

SUMMARY

Antimicrobial stewardship programmes in neonates and children have unique characteristics and issues. There is currently no consensus on how to measure consumption of antimicrobials in neonates and children. This is a research priority. Benchmarking and clinical networks in neonates and paediatrics are important to share practice and drive best use of antimicrobials.

Rapid detection and molecular survey of blaVIM, blaIMP and blaNDM genes among clinical isolates of Acinetobacter baumannii using new multiplex real-time PCR and melting curve analysis

Background

Acinetobacter baumannii is a cosmopolitan bacterium that is frequently reported from hospitalized patients, especially those patients who admitted in the intensive care unit. Recently, multiplex real-time PCR has been introduced for rapid detection of the resistance genes in clinical isolates of bacteria. The current study aimed to develop and evaluate multiplex real-time PCR to detect common resistance genes among clinical isolates of A. baumannii.

Results

Multiplex real-time PCR based on melting curve analysis showed different T_m corresponding to the amplified fragment consisted of 83.5 °C, 93.3 °C and 89.3 °C for blaIMP, blaVIM and blaNDM, respectively. Results of multiplex real-time PCR showed that the prevalence of blaIMP, blaVIM and blaNDM among the clinical isolates of A. baumannii were 5/128(3.9%), 9/128(7.03%) and 0/128(0%), respectively. Multiplex real-time PCR was able to simultaneously identify the resistance genes, while showed 100% concordance with the results of conventional PCR.

Conclusions

The current study showed that blaVIM, was the most prevalent MBL gene among the clinical isolates of A. baumannii while no amplification of blaNDM was seen. Multiplex real-time PCR can be sensitive and reliable technique for rapid detection of resistance genes in clinical isolates.

Carbapenemase-producing Enterobacteriaceae among pregnant women and newborns in Algeria: Prevalence, molecular characterization, maternal-neonatal transmission, and risk factors for carriage

The diffusion of carbapenemase-producing Enterobacteriaceae (CPE) represents a worldwide public health problem. This study revealed that the prevalence of OXA-48-producing enterobacteria was 4.6% (19/414) and 1.6% (7/422) in mothers and newborns, respectively, from 2 maternity units in Algeria. Previous hospital admission was an independent factor associated with an increased risk of CPE carriage in the mothers (P = .021). The low birth weight was significantly associated with this carriage in the newborns (P = .008). The screening of these bacteria is essential to prevent the dissemination of CPE.

Predictors for gut colonization of carbapenem-resistant Enterobacteriaceae in neonates in a neonatal intensive care unit

BACKGROUND

With the emergence of carbapenem-resistant isolates, the therapeutic alternatives have become limited. Various factors are responsible for carbapenem-resistant Enterobacteriaceae (CRE) gut colonization. This study was conducted to determine predictors for CRE gut colonization in neonates who were hospital delivered and admitted in a neonatal intensive care unit (NICU).

METHODS

Three rectal swabs were collected from 300 hospital-delivered and NICU-admitted neonates (likely to stay for >3 days). The data collected for the possible risk factors for CRE gut colonization were namely mode of delivery, prolonged rupture of membrane >18 hours, period of gestation, birth weight, meconium-stained liquor, ventilation, intravenous catheter, nasogastric (NG) tube, NG feeding, breastfeeding, katori spoon feeding, top feeding, expressed breastmilk, antibiotics administration, and duration of hospitalization. P < .05 was considered as statistically significant.

RESULTS

A total of 26 cases of CRE were isolated from 300 neonates. Statistically significant risk factors were found to be NG tube, breastfeeding, NG feeding, top feeding, expressed breastmilk, ventilation, antibiotic administration, and duration of hospitalization. Top feeding and antibiotics administration were identified as 2 independent risk factors by multiple logistic regression.

CONCLUSIONS

Active surveillance of cultures from hospitalized patients and implementation of preventive efforts can reduce the risk of CRE.

Prediction of imipenem-resistant microorganisms among the nosocomial critically ill patients with Gram-negative bacilli septicemia: a simple risk score

Objectives

The increasing number of reports on infections due to carbapenem-resistant Gram-negative bacilli (GNB) has raised concerns, because they have complicated empiric or guided antibiotic therapy for critically ill patients. We aimed to develop a scoring system to predict nosocomial imipenem-resistant GNB (IR-GNB) septicemia among the critically ill patients.

Materials and methods

The study included critically ill adult patients with nosocomial GNB septicemia at Kaohsiung Chang Gung Memorial Hospital (CGMH) in 2013-2015, and the scoring system for predicting IR-GNB septicemia was developed, followed by prospective validation conducted among patients at Linkou CGMH and Kaohsiung CGMH between January and June, 2016.

Results

In the development of the scoring system, 748 patients were included. The independent factors associated with IR-GNB septicemia were prior exposure (days) to carbapenems (adjusted odds ratio [aOR] per 1-day increase, 1.1; 1-3 days: 2 points, 4-6 days: 5 points, 7-9 days: 8 points, and ≥10 days: 13 points), use of mechanical ventilation (aOR 3.7; 5 points), prior colonization with IR-GNB strains (aOR 3.5; 5 points) within 30 days before the onset of GNB septicemia, and comorbid condition with chronic kidney disease (aOR 2.1; 3 points). The internal validation showed an area under the receiver operating characteristic curve (ROC) of 0.75; and an external validation among 314 patients showed similarly good performance (ROC 0.77). Youden's index indicated the score of ≥6 as the best cutoff value with sensitivity of 75% and specificity of 79%.

Conclusion

This scoring system might help clinicians stratify the risk for developing IR-GNB septicemia among critically ill patients and combined antibiotics may be used until antimicrobial de-escalation/adjustment is clearly indicated by the subsequently identified GNB and its susceptibility profile.

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

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

Rapid in situ imaging and whole genome sequencing of biofilm in neonatal feeding tubes: A clinical proof of concept

The bacterial flora of nasogastric feeding tubes and faecal samples were analysed for a low-birth weight (725 g) neonate EGA 25 weeks in intensive care. Samples were collected at age 6 and 8 weeks of life. Optical coherence tomography (OCT) was used to visualise bacterial biofilms inside the nasogastric feeding tubes. The biofilm was heterogeneously distributed along the tube lumen wall, and had a depth of up to 500 µm. The bacterial biofilm and faecal samples included Enterococcus faecalis and Enterobacter hormaechei. Representative strains, recovered from both feeding tubes and faecal samples, were whole genome sequenced using Illumina, Mi-Seq, which revealed indistinguishable strains, each with less than 28 SNP differences, of E. faecalis and E. hormaechei. The E. faecalis strains were from two sequence types (ST191 and ST211) and encoded for a number of traits related to biofilm formation (BopD), adherence (Epb pili), virulence (cps loci, gelatinase, SprE) and antibiotic resistances (IsaA, tetM). The E. hormaechei were all ST106, and encoded for blaACT-15 β–lactamase and fosfomycin resistance (fosA). This proof of concept study demonstrates that bacterial flora within the neonatal feeding tubes may influence the bacterial colonisation of the intestinal tract and can be visualised non-destructively using OCT.

Clonal spread of carbapenem-resistant Acinetobacter baumannii in a neonatal intensive care unit

Acinetobacter baumannii has often been associated with colonization and/or infection in neonatal intensive care units (NICU). This study describes a clonal spread of carbapenem-resistant A. baumannii (CRAB) isolates in an NICU. In total, 21 CRAB isolates were collected from premature newborns. Only polymyxin B was active against such isolates. Nineteen CRAB isolates were clonally related (Cluster C, which belonged to worldwide-disseminated ST1). All newborns had peripheral access and had received β-lactam therapy previously. The implementation of strict infection control measures was of fundamental importance to eradicate the clonal type in the study hospital.

Molecular characterization of intestinal carriage of carbapenem-resistant Enterobacteriaceae among inpatients at two Iranian university hospitals: first report of co-production of bla NDM-7 and bla OXA-48

Gastrointestinal colonization of carbapenem-resistant Enterobacteriaceae (CRE) could serve as a reservoir for the transmission of these pathogens in the clinical setting. The aim of this study was to investigate the intestinal carriage of CRE and to analyze risk factors for CRE carriage. Rectal swabs were collected from 95 patients at two Iranian university hospitals. CRE screening was performed using selective media (CHROMagar and MacConkey agar). Polymerase chain reaction (PCR) was used to detect carbapenemase-encoding genes. Clonal relatedness was investigated by pulsed-field gel electrophoresis (PFGE). The rate of carriage of CRE in hospitalized patients was 37.9%. Overall, 54 CRE isolates were identified, of which 47 were carbapenemase-producers. All of the 54 CRE were detected using CHROMagar compared with 52 CRE detected using MacConkey agar. Fifteen patients were colonized by multiple CRE isolates. Three significant risk factors for CRE carriage were detected: intensive care unit (ICU) hospitalization, antibiotic exposure, and mechanical ventilation. bla _OXA-48 was the most frequent carbapenemase detected, followed by bla _NDM-1 and bla _NDM-7. Eleven carbapenemase-producing Enterobacteriaceae (CPE) isolates co-harbored bla _NDM-1 and bla _OXA-48. Also, six CPE isolates co-harbored bla _NDM-7 and bla _OXA-48. We did not detect bla _KPC, bla _GES, bla _IMP, or bla _VIM. PFGE analysis showed that Escherichia coli clones were diverse, while Klebsiella pneumoniae isolates were divided into four clusters. Cluster I was the major clone carrying bla _OXA-48 and bla _CTX-M-15 genes. In our study, the carriage rate of CRE was high and the emergence of CPE isolates among patients is alarming. The implementation of adequate preventive measures such as active surveillance is urgently needed to control the spread of CPE in the healthcare setting.

Risk factors and clinical outcomes for carbapenem-resistant Gram-negative late-onset sepsis in a neonatal intensive care unit

BACKGROUND

Carbapenem-resistant (CR), Gram-negative (GN), late-onset sepsis (LOS) is a serious threat in the neonatal intensive care unit (NICU).

AIM

To assess the prevalence of CR-GN-LOS in NICU patients and to identify the risk factors and outcomes associated with its acquisition.

METHODS

Neonates with carbapenem-susceptible (CS)-GN-LOS were compared with those with CR-GN-LOS in a two-year observational study.

FINDINGS

A total of 158 patients had GN-LOS; 100 infants had CS-GN-LOS and 58 infants had CR-GN-LOS. The incidence rate of CR-GN-LOS was 6.5 cases per 1000 patient-days. The most frequent bacterial strain in both groups was Klebsiella pneumoniae. The duration of total parenteral nutrition (TPN) (P=0.006) and prior carbapenem use (P=0.01) were independent risk factors for CR-GN-LOS acquisition. CR-GN-LOS was associated with higher mortality than CS-GN-LOS (P=0.04). Birth weight, small for gestational age, time to start enteral feeding, exclusive formula feeding, previous surgery, previous antifungal use, central venous device before onset, duration of central venous device, and infectious complications were identified as dependent risk factors for overall mortality. However, only male gender (P=0.04) and infectious complications (P < 0.001) were independent risk factors associated with mortality. Infectious complication rates, duration of mechanical ventilation, and length of hospital stay were significantly higher in infants with CR compared to CS-GN-LOS.

CONCLUSION

The duration of TPN and carbapenem use were the independent predictors for CR-GN-LOS acquisition. CR-GN-LOS is associated with higher mortality, infectious complication rates, longer mechanical ventilation, and longer hospital stay. Male gender and infectious complications were the independent risk factors for mortality in neonates with GN-LOS.

The carbapenem-resistant Enterobacteriaceae threat is growing: NDM-1 epidemic at a training hospital in Turkey

BACKGROUND

Recently, new carbapenemases in Enterobacteriaceae strains and non-fermentative gram-negative bacilli have been reported. The New Delhi metallo-β-lactamase-1 (NDM-1) is a major problem around the world. The purpose of this article is to address the NDM-1 Klebsiella pneumoniae epidemic detected in eight cases in our hospital.

METHODS

Bacteria identified in this epidemic were from patients already admitted to the intensive care unit of the Sakarya University Training and Research Hospital during efforts toward establishment of infection surveillance and control program. Antimicrobial susceptibility testing of strains was performed using the VITEK 2 system (bioMérieux, France), E-test gradient strips (bioMérieux, France), and the disc diffusion test. For the metallo-beta-lactamase activity, the combined disc diffusion test and modified Hodge test as phenotypic tests were performed. To identify the resistance gene, the Xpert Carba-R kit (Cepheid Inc., USA) and an in-house multiplex polymerase chain reaction (PCR) method designed for five common carbapenemase genes (IMP, VIM, KPC, NDM-1, and OXA-48) were employed. The clonal relationship of these strains was explored by the repetitive PCR (rep-PCR, DiversiLab System, bioMérieux, France) method.

RESULTS

During the December 2014 to March 2015 period, NDM-1 positive K. pneumoniae strains were detected in eight patients. All of these strains were found to produce NDM-1, while two of them also revealed the presence of OXA-48. The rep-PCR results reveal a clonal proximity of 95 % for six of the eight strains.

CONCLUSIONS

Our findings suggest the tendency of NDM-1-producing strains to spread in our country as well. A carbapenem-resistant K. pneumoniae threat may pose a great risk to our country. It is clear that more comprehensive infection control precautions should be implemented in our hospitals.