Transcriptional Analysis of IncFrepB-Mediated blaOXA-48-Positive Plasmid Characterized from Escherichia coli ST448

Objectives: To investigate the transcriptional response of bla_OXA-48 and the copy number alteration of IncF_repB plasmid carrying bla_OXA-48 under an antibiotic concentration gradient. Methods: Escherichia coli strains harboring bla_OXA-48 on an IncFrep_B plasmid were isolated from Silchar Medical College and Hospital, Silchar, India. Sequence type and common resistance determinants were determined by PCR assay. Plasmid copy number alteration and the transcriptional expression of bla_OXA-48 under different antibiotic pressures were determined by quantitative real-time PCR, and the relative fold change was measured by the ΔΔCT method. Results and Conclusion: The plasmid that carried bla_OXA-48 in E. coli ST448 was characterized as IncFrep_B and found to be conjugatively transferable. The isolates were found to coexist with bla_NDM-1 within the IncX3-type plasmid. It was observed that the copy number and transcriptional response of bla_OXA-48 were directly proportional to the increasing concentration of meropenem and ertapenem, whereas in the case of imipenem, it was reversed. The identification of bla_OXA-48 through IncF_repB-type plasmid in this study indicates the potential route of spread of this resistance determinant in this area and also the insights we gained from the transcriptional changes of bla_OXA-48 in response to different antibiotic pressures could also facilitate the development of novel or alternative therapeutic options needed for multidrug-resistant infections.

Use of fluorescence foldscope as an effective tool for detection of biofilm formation in Pseudomonas aeruginosa

Purpose

Pseudomonas aeruginosa is an opportunistic pathogen with biofilm-forming ability, by the virtue of which they can evade the immune response and antimicrobial chemotherapy. Several methods have been designed for the detection of biofilms but require sophisticated instrumentation and expertise. The present study, therefore, used an improvised device, 'fluorescence foldscope' which is an origami-based fluorescence microscope as an easy and effective tool to detect biofilm formation.

Methodology

Three representatives of P. aeruginosa of clinical origin were taken for the study along with two reference strains PA01 and ATCC27853. The strains were cultured in Luria Bertani (LB) broth with and without carbapenem (imipenem and meropenem) and cephalosporin (ceftazidime, cefotaxime and ceftriaxone) pressure, respectively. The cultures were diluted to 1:100 in LB; seeded with sterile glass slides at 90° angle and incubated for 5 consecutive days. The slides were observed with fluorescence foldscope.

Results

Fluorescence emission was observed in two test isolates CD1 and CD2 at 48 and 72 h, respectively, whereas no fluorescence was observed in CD3. The fluorescence observed in the isolates was not affected by 2 μg/ml carbapenem pressure, while with 2 μg/ml ceftazidime stress, a change in fluorescence was observed in CD2 in comparison to the fluorescence observed under normal growth condition.

Conclusion

Fluorescence foldscopy is an effective and reliable tool for the detection of biofilm formation in clinical isolates of P. aeruginosa under different laboratory conditions. Biofilm-forming P. aeruginosa worsens the medical condition and is difficult to eradicate. The present study came up with an effective and reliable tool for the detection of biofilm formation in clinical isolates of P. aeruginosa.

Rationale and study design for lifestyle intervention in preparation for pregnancy (LIPP): A randomized controlled trial

INTRODUCTION

Maternal obesity increases neonatal risk for obesity and metabolic syndrome later in life. Prior attempts to break this intergenerational obesity cycle by limiting excessive gestational weight gain have failed to reduce neonatal adiposity. Alternatively, pre-conception lifestyle interventions may improve the in utero metabolic milieu during early pregnancy leading to improved fetal outcomes. This randomized controlled trial (RCT) is evaluating whether a lifestyle intervention to reduce weight and improve maternal metabolism in preparation for pregnancy (LIPP) attenuates neonatal adiposity, compared to standard medical advice.

MATERIAL AND METHODS

Overweight/class 1 obese women after a previous pregnancy, ~12 weeks postpartum, preparing for a subsequent pregnancy, will be block randomized (1:1) to either LIPP or standard of care in a parallel design. Randomization is stratified by lactation status and overweight vs. class 1 obesity. The LIPP program consists of intensive short-term weight loss followed by weight maintenance until conception using supervised exercise and a low glycemic Mediterranean diet.

PRIMARY OUTCOMES

Group differences in neonatal adiposity at birth assessed by PEA POD and placental mitochondrial lipid metabolism.

SECONDARY OUTCOMES

Group differences in maternal pregravid and gestational body composition, insulin sensitivity, β-cell function, fasting metabolic and inflammatory biomarkers, and overall quality of life. Exploratory outcomes include umbilical cord blood insulin resistance, lipid profile and inflammation.

DISCUSSION

This RCT will determine the efficacy of maternal weight loss prior to pregnancy on reducing neonatal adiposity. Findings may change standard obstetrical care by providing Level 1 evidence on lifestyle interventions improving neonatal outcomes for women planning for pregnancy.

CLINICAL TRIAL REGISTRATION

NCT03146156.

Distribution of carbapenem resistant Acinetobacter baumannii with blaADC-30 and induction of ADC-30 in response to beta-lactam antibiotics

A wide range of intrinsic Acinetobacter-derived cephalosporinases (ADC) along with other carbapenemases has now been detected in Acinetobacter baumannii leaving clinicians with few treatment options. The present study reports the spread of ADC-30 co-producing KPC-2 along with other β-lactamases among carbapenem resistant A. baumannii strains obtained from ICU patients in two Indian hospitals. Primer extension analysis revealed higher transcript level of the ADC gene when induced with cefoxitin at 8 μg/ml (170 fold), ceftriaxone at 8 μg/ml (136 fold), ceftazidime at 4 μg/ml (65 fold), cefepime at 8 μg/ml (77 fold) and aztreonam at 8 μg/ml (21 fold) when compared with the basal level without antibiotic pressure. Slight increase in expression of bla_ADC-30 when induced with imipenem and meropenem at 0.25 μg/ml (3 and 6 fold) was observed and may help in conferring resistance to carbapenem. MLST analysis revealed the circulation of A. baumannii sequence types ST188, ST386, ST583 and ST390 in these hospitals.

DURABLE RESPONSE IN A CASE OF METASTATIC ANAPLASTIC THYROID CANCER USING A COMBINATION OF TYROSINE KINASE INHIBITORS AND A CHECK POINT INHIBITOR

Anaplastic thyroid cancer (ATC) is a highly uncommon (less than 2% of thyroid malignancies) and aggressive type of cancer, with aggressive behavior and, therefore, exhibiting poor prognosis. ATC tumors are automatically labeled as stage IV disease regardless of standard criteria such as tumor burden or metastasis. ATC tumors require a diversified treatment approach that includes surgical resection, followed by a complete an aggressive combination of radiation and chemotherapy and/or palliative care. Despite best efforts, 1-year overall survival of patients is 20% to 40% with nearly universal mortality rate. Consequently, novel approaches (targeted therapy, immunotherapy) have been studied, alone or in combination, to improve the dire prognosis of these patients. BRAF V600E mutation is the most common genetic mutation found in ATC. We report the case of a 57-year-old man diagnosed with stage IVc (undifferentiated) ATC with hepatic and osseous metastases. The molecular analysis of the tumor revealed a V600E BRAF-mutation. The patient was treated with Dabrafenib and Trametinib, and achieved remission 5 weeks after starting the treatment. Subsequently, he had a thyroidectomy, and pembrolizumab was added to the two tyrosine kinase inhibitors. 9 months later he is still in remission. This case illustrates the importance of obtaining molecular information in anaplastic thyroid cancer and the urgent need of studies investigating the combination of tyrosine kinase inhibitors and check-point inhibitors in patients with V600E BRAF- mutations.

Occurrence of diverse aminoglycoside modifying enzymes with co-existing extended-spectrum-β-lactamases within Enterobacteriaceae isolated in India

OBJECTIVE

The present study describes aminoglycoside modifying enzymes (AMEs) among clinical isolates with coexisting extended spectrum beta-lactamases.

METHODOLOGY

A total of 227 non duplicate enterobacterial isolates were collected and identified from patients who were admitted to different wards or attended OPD of a tertiary referral hospital of North-East India. Isolates were initially screened for antimicrobial susceptibility testing followed by PCR based screening of aminoglycosides modifying enzymes and co-existing ESBLs and carbapenemases. Horizontal transferability, incompatibility typing and stability of plasmids were also analyzed.

RESULTS

Diverse types of AMEs were observed namely; ant(3″)-I, ant(4')-Ia, aac(3)-IIc, ant(3')-I, aac(6')-Ib, ant(2″)-Ia and aac(6'). Majority of the AME positive isolates harboured bla_TEM followed by bla_CTX-M-15 and a combination of bla_TEM and bla_CTX-M-15 were also observed. Nine isolates were found to harbour carbapenemases genes. AME genes were found to be located within a self conjugative plasmid of Inc FIA, IncY, IncN, IncFIB and IncA/C incompatibility types. It was observed that most AME genes were stable over 50 days of serial passages whereas aph(3')-Via and aph(3')-IIb were completely lost within 50 days.

CONCLUSION

This study underscores the co-existence of AMEs and ESBLs within enterobacteriaceae which emphasize a reassessment of combination therapy in the health settings.

Adaptation of blaNDMthrough IncP plasmid within broad host range

Introduction

It was also known that the IncP-1 plasmids are ubiquitous in environmental bacteria and those reside in soil, sewage, marine sediments and in manure. The blaNDMis associated with resistance determinants along with various mobile elements such as plasmid, insertion sequences and transposons, which facilitates its horizontal dissemination. These plasmids, if tracked, can be a starting point for the control of infection due to multidrug-resistant pathogens. The aim of the study was to investigate that IncP-type plasmids carrying blaNDMis adapted in different hosts.

Materials and Methods

Thirteen of the isolates were harbouring IncP-type plasmid and they all were Escherichia coli isolated from hospitalised patients of Silchar Medical College and Hospital, India. The isolates were checked for susceptibility test, and the stability was assessed by a serial passage. These isolates were further subjected to transcriptional analysis of NDM gene as well as plasmid copy number alteration.

Results

The study isolates were highly stable, and the resistance gene (blaNDM) was retained within isolates till 55th subsequent serial passages. Plasmid copy number alteration was random in isolates when exposed to carbapenem antibiotics, whereas increasing trend in transcriptional expression was observed with the increase in imipenem concentration.

Conclusion

This study was able to underscore the presence of IncP plasmid that was harbouring blaNDMand was maintained within diverse host. The finding also highlights the adaptation of the broad-host-range plasmid that responds in terms of transcriptional expression under antibiotic exposure.

An insight into analysis and elimination of plasmids encoding metallo-β-lactamases in Pseudomonas aeruginosa

OBJECTIVES

The aim of this study was to characterise metallo-β-lactamase (MBL)-harbouring plasmids, their change in copy number in respect to different antibiotic pressure, and the efficiency of different curing agents in eliminating these resistance plasmids from nosocomial Pseudomonas aeruginosa isolates.

METHODS

Plasmids were extracted from four isolates harbouring bla_NDM-1 or bla_VIM-2 under four different concentrations of imipenem, meropenem, ertapenem, aztreonam and cefotaxime. Quantitative real-time PCR was performed to analyse the change in plasmid copy number under these different conditions. The effect of different physical and chemical curing agents in elimination of plasmids carrying bla_NDM-1 and bla_VIM-2 was examined, with meropenem resistance used as a selectable marker.

RESULTS

Conjugatively transferable MBL genes (bla_NDM-1 and bla_VIM-2) carried on plasmids were found to be highly stable. Sodium dodecyl sulfate (SDS) was the most effective agent in eliminating these resistance plasmids. The change in copy number of the bla_NDM-1-encoding plasmid was found to be similar to the bla_VIM-2-encoding plasmid, with a single exception under cefotaxime pressure.

CONCLUSION

The spread of multidrug resistance plasmids has been noted as a key factor associated with increasing carbapenem resistance. Successful curing of resistance plasmids can reverse the bacterial phenotype back to susceptible. This study revealed that different antibiotic pressure induces a change in copy number of MBL-encoding plasmids. SDS can be successfully used as an eliminating agent for these resistance determinants, although therapeutic application of this agent is not possible due to its high toxicity and mutagenic nature.

AcrAB-TolC efflux pump system plays a role in carbapenem non-susceptibility in Escherichia coli

Background

Efflux pump mediated antibiotic resistance is an unnoticed and undetected mechanism in clinical microbiology laboratory. RND efflux systems are known for aminoglycoside and tetracycline resistance whereas their role in carbapenem non-susceptibility is not established. The study was undertaken to investigate the role of efflux pump in providing resistance against carbapenems and their response against concentration gradient carbapenem stress on the transcriptional level of the AcrAB gene in the clinical isolates of Escherichia coli from a tertiary referral hospital of Northeast India.

Results

Out of 298 non-susceptible Escherichia coli isolates 98 isolates were found to have efflux pump mediated carbapenem non-susceptibility. Among them thirty-five were non carbapenemase producers and their expressional levels were verified using qRT-PCR under concentration gradient carbapenem stress. In this study, a strong correlation between ertapenem resistance and AcrA overexpression was observed which has not been reported previously. Further, it was observed that imipenem stress increased AcrB expression in Escherichia coli which holds the novelty of this study. Additionally, the transcription of AcrR was insistently increased which is much higher than the transcriptional level of AcrA under concentration gradient carbapenem stress condition.

Conclusion

The study established that AcrAB pump is a relevant antibiotic resistance determinant in bacterial pathogen, has an important role in developing resistance against carbapenem group of antibiotics.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1589-1) contains supplementary material, which is available to authorized users.

Prevention and reversal of Type 2 diabetes: highlights from a symposium at the 2019 Diabetes UK Annual Professional Conference

AIM

This symposium covers the gamut of Type 2 diabetes prevention, reversing established Type 2 diabetes, population-level delivery of weight loss programmes and personal insights into achieving and retaining substantial weight loss.

RESULTS

The NHS Diabetes Prevention Programme was launched in 2016 and rates of referral and attendance have both exceeded expectations. By March 2018, mean weight loss for completers (those attending more than 60% of sessions) was 3.2 kg reflecting considerable health benefits. Established Type 2 diabetes is now known to be a reversible condition in the early years, and the underlying mechanism is the removal of the excess fat from within liver and pancreas in these susceptible individuals. The Diabetes Remission Clinical Trial has shown that around half of a primary care population of people with Type 2 diabetes of less than 6 years' duration can be returned to non-diabetic blood glucose control which lasts at least 12 months. This raises the question of population-level intervention to achieve weight loss. The success of some mass weight loss programmes requires to be recognized. Reframing mass provision of weight loss support should be a vital part of our clinical strategy to prevent and treat Type 2 diabetes. However, the current obesogenic environment is a reality in which individuals must live. A personal account of achieving substantial and maintaining substantial weight loss provides an invaluable insight into practical problems encountered. All health professionals dealing with weight control should assimilate and reflect upon this understanding.

CONCLUSIONS

Effective prevention and long term reversal of Type 2 diabetes is feasible. The impact upon the individual must be considered during delivery of advice and support.

PREVALENCE OF GESTATIONAL DIABETES MELLITUS IN AN URBAN INDIAN COHORT USING DIABETES IN PREGNANCY STUDY GROUP IN INDIA (DIPSI) CRITERIA – VALIDATING ONE-STEP APPROACH

Background. India is the “World’s Diabetes capital”, with half the diabetic population being women. Early detection of glucose intolerance during pregnancy offers a timely opportunity for screening, management and prevention of gestational diabetes mellitus (GDM) and prevents fetal complications. Objective. The study assessed the prevalence of GDM in an Indian cohort using the Diabetes in Pregnancy Study group of India (DIPSI) criteria. Methods. 200 pregnant women underwent two-phase testing with non-fasting 75-gram glucose challenge under Diabetes in Pregnancy Study group of India (DIPSI) criteria at <20 weeks and between 24-28 weeks period of gestation. A 3-hour 100-gm oral glucose tolerance test (OGTT) was used for confirmation. Repeat testing was done for women negative during the first-phase. Results. Mean age was 24.26±3.75 years with 52.5% multigravidas. Mean Body Mass Index (BMI) was 20.7±3.07 kg/m2. The prevalence of GDM in study cohort was found to be 15.5% using the DIPSI criteria while the prevalence of GDM after 100 g OGTT was 13.0%. GDM was mostly seen to occur in women of 26-30-year age group. Statistically significant associations for age and GDM, and BMI and GDM were evidenced. Conclusions. Maternal age of ≥25 years should be adopted as a risk factor for the development of GDM. The DIPSI criteria offer a cost-effective and an evidence-based protocol for a single-step definitive glucose test for both screening and diagnosis of pregnant patients belonging to any socio-economic strata; furthering its implementation for public health obstetrics.

Observation of a new pattern of mutations in gyrA and parC within Escherichia coli exhibiting fluroquinolone resistance

Therapeutic options with quinolones are severely compromised in infections caused by members of Enterobacteriaceae family. Mutations in chromosomal region are one of the major reasons for bacterial resistance towards this group of antibiotic. The aim of the study is to detect the mutations in gyr A and par C responsible for quinolone resistance among clinical isolates of Escherichia coli. A total of 96 quinolone-resistant clinical isolates of E. coli were collected from a tertiary care hospital of North-east India during March 2015 to August 2015. All the quinolone-resistant E. coli strains were investigated for mutations in the topoisomerases genes gyrA and parC by amplifying and sequencing the quinolone resistance determining regions. Among the 96 E. coli isolates, 83.3% were resistant to nalidixic acid and 80.2%, 66.6%, 23.9% and 50% to ciprofloxacin, norfloxacin, levofloxacin and ofloxacin, respectively. Several alterations were detected in gyrA and parC genes. Three new patterns of amino acid substitution are reported in E. coli isolates. The findings of this study warrant a review in quinolone-based therapy in this region of the world to stop or slow down the irrational use this drug.