Browsing by Author "Amitabha Bhattacharjee"

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Antimicrobial susceptibility of Pseudomonas aeruginosa isolated from wound infections
(Medknow Publications and Media Pvt. Ltd, 2006) Shampa Anupurba; Amitabha Bhattacharjee; Atul Garg; Malay Sen
The primary aim of this study was to determine the prevalence of Pseudomonas aeruginosa in wound infections and its sensitivity to the commonly used antibiotics at SS Hospital, Varanasi, India. We received 940 relevant clinical specimens among, which 301 (32%) was P. aeruginosa. Antibiotic susceptibility was determined by the disc diffusion method where cefoperazone/sulbactam was found to be most effective (74%) followed by ciprofloxacin (58%) and ceftazidime (54%). Rest of the antibiotics showed a very low level of susceptibility pattern. A total of 54 (18%) isolates were resistant to all the antibiotics tested in vitro.
Characterization of blaOXA-232 carrying carbapenem-resistant Klebsiella pneumoniae (CRKP) & their expression profiles under selective carbapenem pressure: An in-depth study from India
(Scientific Scholar LLC, 2024) Bhaskar Jyoti Das; Tuhina Banerjee; Jayalaxmi Wangkheimayum; Kajal Mishra; Ashok Kumar; Amitabha Bhattacharjee
Background & objectives: OXA-232 is a five amino acid substitution variant of OXA-48 and is reported in carbapenem-resistant Klebsiella pneumoniae (CRKP), which is associated with nosocomial infections among immunocompromised patients in the intensive care unit. This study aimed to characterise blaOXA-232 in CRKP of clinical origin and investigate its transcriptional response against sub-inhibitory levels of carbapenems. Methods: CRKP was isolated from blood (pathogens) and stool cultures (colonisers) of neonates and was characterized for blaOXA-232. Co-existing resistance determinants were investigated in blaOXA-232 positive isolates, followed by horizontal gene transferability assay and PCR-based replicon typing (PBRT). Cloning of blaOXA-232 was performed, and expression of blaOXA-232 in the isolates and their clones under sub-inhibitory concentrations of carbapenems was checked via RT-PCR. Mobile genetic elements associated with blaOXA-232 were investigated, followed by DNA fingerprinting through enterobacterial repetitive intergenic consensus (ERIC) PCR. Results: blaOXA-232 with co-carriage of extended-spectrum beta-lactamases (ESBLs), sulphonamides and quinolones were identified in seven CRPK isolates recovered from blood samples of neonates. Transformation and cloning of blaOXA-232 was successful. The sub-inhibitory concentration of carbapenems induces elevated expression of this resistant determinant. ISEcp1 was associated with blaOXA-232 in the upstream region within two haplotypes of CRKP isolates of clinical origin. Interpretation & conclusions: Selective carbapenem pressure resulted in higher expression of this gene, which could account for treatment failure. With frequent reports of occurrence among clinical isolates, monitoring and further investigation of this novel variant are necessary to understand its transmission dynamics and to thwart its further dissemination. © 2024 Indian Journal of Medical Research, published by Scientific Scholar for Director-General, Indian Council of Medical Research.
Co-carriage of blaKPC-2 and blaNDM-1 in clinical isolates of Pseudomonas aeruginosa associated with hospital infections from India
(Public Library of Science, 2015) Deepjyoti Paul; Debadatta Dhar Chanda; Anand Prakash Maurya; Shweta Mishra; Atanu Chakravarty; Gauri Dutt Sharma; Amitabha Bhattacharjee
Global spread of KPC poses to be a serious threat complicating treatment options in hospital settings. The present study investigates the genetic environment of blaKPC-2 among clinical isolates of Pseudomonas aeruginosa from a tertiary referral hospital of India. The study isolates were collected from different wards and clinics of Silchar Medical College and Hospital, India, from 2012-2013. The presence of blaKPC was confirmed by genotypic characterization followed by sequencing. Cloning of the blaKPC-2 gene was performed and the genetic environment of this gene was characterized as well. Transferability of the resistance gene was determined by transformation assay and Southern hybridization. Additionally restriction mapping was also carried out. Two isolates of P. aeruginosa were found to harbor blaKPC-2 were resistant towards aminoglycosides, quinolone and β-lactam-β-lactamase inhibitor combination. In both the isolates, the resistance determinant was associated with class 1 integron and horizontally transferable. Both the isolates were co-harboring blaNDM-1. The first detection of this integron mediated blaKPC-2 coexisting with blaNDM-1 in P. aeruginosa from India is worrisome, and further investigation is required to track the gene cassette mediated blaKPC-2 in terms of infection control and to prevent the spread of this gene in hospitals as well as in the community. © 2015 Paul et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Detection and characterisation of AmpC β-lactamase-producing isolates of Acinetobacter spp. in North India
(2010) Supriya Upadhyay; Malay Ranjan Sen; Pradyot Prakash; Shampa Anupurba; Gopal Nath; Amitabha Bhattacharjee
[No abstract available]
Detection of OXA-2 group extended-spectrum-β-lactamase-producing clinical isolates of Escherichia coli from India [2]
(2007) Amitabha Bhattacharjee; Malay Ranjan Sen; Shampa Anupurba; Pradyot Prakash; Gopal Nath
[No abstract available]
Diagnostic utility of boronic acid inhibition with different cephalosporins against Escherichia coli producing AmpC β-lactamases
(2011) Supriya Upadhyay; Malay Ranjan Sen; Amitabha Bhattacharjee
[No abstract available]
Diagnostic utility of combination of inducer and inhibitor based assay in detection of Pseudomonas aeruginosa producing AmpC β-lactamase
(2011) Supriya Upadhyay; Malay Ranjan Sen; Amitabha Bhattacharjee; Pradyot Prakash; Ram Chandra Bajpai; Shampa Anupurba
The diagnostic utility of inducer and inhibitor based assays among 214 AmpC positive isolates of Pseudomonas aeruginosa were evaluated. Of different methods, combination of ceftazidime-imipenem antagonism and boronic acid inhibition tests came up with maximum sensitivity (76%) and specificity (100%). This combination showed reliability for both inducible and non-inducible AmpC producers. © 2011 Elsevier B.V.
Dissemination of the New Delhi metallo-b-lactamase-1 (NDM-1) among Enterobacteriaceae in a tertiary referral hospital in north India
(2011) Kumari Seema; Malay Ranjan Sen; Supriya Upadhyay; Amitabha Bhattacharjee
[No abstract available]
Diverse Genetic Array of blaCTXM-15 in Escherichia coli: A Single-Center Study from India
(Mary Ann Liebert Inc., 2016) Anand Prakash Maurya; Shweta Mishra; Anupam Das Talukdar; Debadatta Dhar Chanda; Atanu Chakravarty; Amitabha Bhattacharjee
CTX-M-15 is a chief contributor for expanded-spectrum cephalosporin and monobactam resistance in India, complicating treatment options. In this study, we have investigated genetic context of CTX-M-15 in Escherichia coli and their transmission dynamics in a tertiary referral hospital of India. A total of 198 isolates were collected, of which 66 were harboring blaCTXM-15. Among them, 14 isolates were carrying a single CTX-M-15 gene and 52 were harboring multiple extended-spectrum β-lactamase genes along with blaCTX-M-15. The resistance gene was flanked by tnpA, ISEcp1, IS26, and ORF477 in 10 different arrangements. The resistance determinant was horizontally transferable through F, W, I1, and P Inc types of plasmids. Restriction mapping of plasmids showed a variable band pattern even within the same Inc types. Minimum inhibitory concentration was found above the breakpoint level against expanded-spectrum cephalosporins and monobactam while susceptible against carbapenems. blaCTX-M-15 was highly stable and sustained in the cell after 115 serial passages. In pulse-field gel electrophoresis, eight pulsotypes of E. Coli were found to be responsible for the spread of blaCTX-M-15 in the tertiary referral center. We conclude that the presence of CTX-M-15 in the heterogeneous group of E. Coli is highly alarming in terms of infection control and it may require regular monitoring, so as to formulate appropriate antibiotic policy to stop the spread of this resistance determinant. © Copyright 2016, Mary Ann Liebert, Inc. 2016.
Expansion of highly stable bla OXA-10 β-lactamase family within diverse host range among nosocomial isolates of Gram-negative bacilli within a tertiary referral hospital of Northeast India
(BioMed Central Ltd., 2017) Anand Prakash Maurya; Debadatta Dhar; Mridul Kumar Basumatary; Deepjyoti Paul; Birson Ingti; Debarati Choudhury; Anupam Das Talukdar; Atanu Chakravarty; Shweta Mishra; Amitabha Bhattacharjee
Background: The current study reports dissemination of highly stable bla OXA-10 family of beta lactamases among diverse group of nosocomial isolates of Gram-negative bacilli within a tertiary referral hospital of the northern part of India. Methods: In the current study, a total number of 590 Gram negative isolates were selected for a period of 1 year (i.e. 1st November 2011-31st October 2012). Members of Enterobacteriaceae and non fermenting Gram negative rods were obtained from Silchar Medical College and Hospital, Silchar, India. Screening and molecular characterization of β-lactamase genes was done. Integrase gene PCR was performed for detection and characterization of integrons and cassette PCR was performed for study of the variable regions of integron gene cassettes carrying bla OXA-10. Gene transferability, stability and replicon typing was also carried out. Isolates were typed by ERIC as well as REP PCR. Results: Twenty-four isolates of Gram-negative bacilli that were harboring bla OXA-10 family (OXA-14, and OXA16) with fact that resistance was to the extended cephalosporins. The resistance determinant was located within class I integron in five diverse genetic contexts and horizontally transferable in Enterobacteriaceae, was carried through IncY type plasmid. MIC values were above break point for all the tested cephalosporins. Furthermore, co-carriage of bla CMY-2 was also observed. Conclusion: Multiple genetic environment of bla OXA-10 in this geographical region must be investigated to prevent dissemination of these gene cassettes within bacterial population within hospital settings. © 2017 The Author(s).
Extensively Drug-Resistant Hypervirulent Klebsiella pneumoniae From a Series of Neonatal Sepsis in a Tertiary Care Hospital, India
(Frontiers Media S.A., 2021) Tuhina Banerjee; Jayalaxmi Wangkheimayum; Swati Sharma; Ashok Kumar; Amitabha Bhattacharjee
The recent emergence of multidrug-resistant (MDR) Klebsiella pneumoniae with hypervirulent traits causing severe infections and considerable mortality is a global cause for concern. The challenges posed by these hypermucoviscous strains of K. pneumoniae with regard to their optimal treatment, management, and control policies are yet to be answered. We studied a series of extensively drug-resistant (XDR) and hypervirulent K. pneumoniae ST5235 isolates with resistance to carbapenems and polymyxins causing neonatal sepsis in a tertiary care hospital in India. A total of 9 K. pneumoniae isolates from 9 cases of neonatal sepsis were studied with respect to their clinical relevance, antimicrobial susceptibility profile, presence of extended spectrum β lactamase (ESBL) production, and responsible genes, carbapenemases (classes A, B, and D), and aminoglycoside-resistant genes. Hypervirulence genes encoding hypermucoid nature, iron uptake, and siderophores were detected by multiplex PCR. The plasmid profile was studied by replicon typing. Isolates were typed by multilocus sequence typing (MLST) and enterobacterial repetitive intergenic consensus (ERIC) PCR to study the sequence types (STs) and clonal relation, respectively. The neonates in the studied cases had history of pre-maturity or low birth weight with maternal complications. All the cases were empirically treated with piperacillin–tazobactam and amikacin followed by imipenem/meropenem and vancomycin and polymyxin B as a last resort. However, all the neonates finally succumbed to the condition (100%). The studied isolates were XDR including resistance to polymyxins harboring multiple ESBL genes and carbapenemase genes (blaNDM and blaOXA−48). Hypervirulence genes were present in various combinations with rmpA/A2 genes present in all the isolates. IncFI plasmids were detected in these isolates. All belonged to ST5235. In ERIC PCR, 6 different clusters were seen. The study highlighted the emergence and burden of XDR hypervirulent isolates of K. pneumoniae causing neonatal sepsis in a tertiary care hospital. © Copyright © 2021 Banerjee, Wangkheimayum, Sharma, Kumar and Bhattacharjee.
Genetic acquisition of NDM gene offers sustainability among clinical isolates of Pseudomonas aeruginosa in clinical settings
(Public Library of Science, 2015) Shweta Mishra; Supriya Upadhyay; Malay Ranjan Sen; Anand Prakash Maurya; Debarati Choudhury; Amitabha Bhattacharjee
New Delhi metallo β-lactamases are one of the most significant emerging resistance determinants towards carbapenem drugs. Their persistence and adaptability often depends on their genetic environment and linkage. This study reports a unique and novel arrangement of blaNDM-1 gene within clinical isolates of Pseudomonas aeruginosa from a tertiary referral hospital in north India. Three NDM positive clonally unrelated clinical isolates of P. aeruginosa were recovered from hospital patients. Association of integron with blaNDM-1 and presence of gene cassettes were assessed by PCR. Genetic linkage of NDM gene with ISAba125 was determined and in negative cases linkage in upstream region was mapped by inverse PCR. In which only one isolate's NDM gene was linked with ISAba125 for mobility, while other two reveals new genetic arrangement and found to be inserted within DNA directed RNA polymerase gene of the host genome detected by inverse PCR followed by sequencing analysis. In continuation significance of this novel linkage was further analyzed wherein promoter site detected by Softberry BPROM software and activity were assessed by cloning succeeding semi-quantitative RT-PCR indicating the higher expression level of NDM gene. This study concluded out that the unique genetic makeup of NDM gene with DNA-dependent-RNA-polymerase favours adaptability to the host in hospital environment against huge antibiotic pressure. © 2015 Mishra et al.
Genetic environment of plasmid mediated CTX-M-15 extended spectrum beta-lactamases from clinical and food borne bacteria in north-eastern India
(Public Library of Science, 2015) Supriya Upadhyay; Abbas Hussain; Shweta Mishra; Anand Prakash Maurya; Amitabha Bhattacharjee; Santa Ram Joshi
Background The study investigated the presence of CTX-M-15 type extended spectrum beta-lactamases (ESBL), compared their genetic arrangements and plasmid types in gram negative isolates of hospital and food origin in north-east India. From September 2013 to April 2014, a total of 252 consecutive, non-duplicate clinical isolates and 88 gram negative food isolates were selected. Phenotypic and molecular characterization of ESBL genes was performed. Presence of integrons and gene cassettes were analyzed by integrase and 59 base-element PCR respectively. The molecular environments surrounding blaCTX-M and plasmid types were investigated by PCR and PCR-based replicon typing respectively. Transformation was carried out to assess plasmid transfer. Southern blotting was conducted to localize the blaCTX-M-15 genes. DNA fingerprinting was performed by ERIC-PCR. Results Prevalence of ESBL was found to be 40.8% (103/252) in clinical and 31.8% (28/88) in foodborne isolates. Molecular characterization revealed the presence of 56.3% (58/103) and 53.5% (15/28) blaCTX-M-15 in clinical and food isolates respectively. Strains of clinical and food origin were non-clonal. Replicon typing revealed that IncI1 and IncFII plasmid were carrying blaCTX-M-15 in clinical and food isolates and were horizontally transferable. The ISEcp1 element was associated with blaCTX-M-15 in both clinical and food isolates. Conclusions The simultaneous presence of resistance determinants in non-clonal isolates of two different groups thus suggests that the microbiota of common food products consumed may serve as a reservoir for some of the drug resistance genes prevalent in human pathogens. © 2015 Upadhyay et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Genetic linkage of blaNDM among nosocomial isolates of Acinetobacter baumannii from a tertiary referral hospital in northern India
(2013) Shweta Mishra; Malay Ranjan Sen; Supriya Upadhyay; Amitabha Bhattacharjee
The aim of this study was to evaluate the emergence of blaNDM-1 among clinical isolates of Acinetobacter baumannii isolated from a north Indian tertiary care hospital and to assess the gene cassettes and resistance determinants located within them. In total, 74 A. baumannii were screened for MBL production by the imipenem-EDTA method and were characterised for antibiotic sensitivity. PCR was performed to detect the presence of blaNDM and the co-existence of ESBL and AmpC genes. NDM-producing isolates were typed by ERIC-PCR, and the association of integrons with blaNDM-1 and the presence of gene cassettes were determined using specific primers. The genetic location of blaNDM in ISAba125 was also determined. Transformation was performed using a heat-shock method. Three isolates were found to harbour blaNDM, all of which co-produced blaEBC, blaDHA and blaCIT AmpC β-lactamases. All MBL-producers showed resistance to cephalosporins, carbapenems, aminoglycosides, fluoroquinolones and tigecycline but were susceptible to polymyxin B. Presence of class 1 integrons was demonstrated in all three blaNDM-harbouring isolates, whilst linkage between the integron and blaNDM could not be established. Detection of gene cassettes revealed the presence of dihydrofolate reductase (dhfr) and aminoglycoside 6′-N-acetyltransferase [aac(6′)] genes. Presence of blaNDM in ISAba125 was also observed. These findings suggest that ISAba125 appears to be the main genetic component for dissemination of blaNDM in A. baumannii. The association of blaNDM-1 with ISAba125 and the mobility of other multiresistance region (gene cassette)-carrying integrons provide an easy way to cross species barriers and reach a level that places the patients at risk.
Linoleic acid acts as a potential anti-virulence agent in Klebsiella pneumoniae
(European Academy of HIV/AIDS and Infectious Diseases, 2024) Jayalaxmi Wangkheimayum; Tuhina Banerjee; Somorita Baishya; Swati Sharma; Manabendra Dutta Choudhury; Monjur Ahmed Laskar; Amitabha Bhattacharjee
Introduction The rise in antimicrobial resistance among bacterial pathogens is a global concern, and anti-virulence therapy may be an alternative strategy to address the issue. Multidrug resistant (MDR) hypervirulent Klebsiella pneumoniae (HvKp) is known to be associated with healthcare associated infections. These are often challenging to treat and here anti-virulence therapy may be a treatment option. The study of anti-virulence compounds against HvKp by in-silico prediction, in-vitro experiments and in-vivo assay enables to determine which anti-virulence compounds are suitable for an alternative approach MDR HvKp. Methods Modeling of the proteins, ligand binding and molecular docking were performed targeting different hypervirulence genes viz., rmpA, rmpA2 and, iroC by in-silico analysis using different bioinformatics tool and software. Minimum inhibitory concentration (MIC) was determined for six anti-virulence compounds; curcumin, eugenol, reserpine, linoleic acid, Ɛ-anethole, and α-thujone by standard protocol. Quantitative real-time PCR was performed selecting two isolates harboring rmpA, rmpA2 and iroC genes. Galleria mellonella larva killing assay was used for in-vivo experiment. Results In-silico analysis observed that linoleic acid could be the best fit in comparison with the other compounds. None of the anti-virulence compounds showed any inhibitory activity and upon transcriptional expression analysis of the hypervirulence genes; rmpA was marginally increased for both the isolates when linoleic acid exposure was given. Conclusions In-vivo study revealed that linoleic acid and reserpine showed anti-virulence activity. © GERMS 2024.
Long-term outbreak of Klebsiella pneumoniae & third generation cephalosporin use in a neonatal intensive care unit in North India
(Indian Council of Medical Research, 2016) Tuhina Banerjee; Amitabha Bhattacharjee; Supriya Upadhyay; Shweta Mishra; Karuna Tiwari; Shampa Anupurba; Malay Ranjan Sen; Sriparna Basu; Ashok Kumar
Background & objectives: The indiscriminate use of third generation cephalosporin has contributed to the emergence and widespread dissemination of extended spectrum β lactamases (ESBL) genes in Klebsiella pneumoniae. This study was undertaken to elaborate the genetic behaviour of ESBL - producing K. pneumoniae isolates in the neonatal intensive care unit (NICU) of a tertiary care hospital in north India causing successive outbreaks in context with empirical third generation cephalosporin use. Methods: Isolates of K. pneumoniae (43 from blood, 3 from pus and endotracheal tube, 4 from environment) causing successive outbreaks in the NICU of a tertiary care university hospital were studied for two years. Antimicrobial susceptibility testing was done by disc diffusion and minimum inhibitory concentration (MIC) determination by agar dilution methods. ESBL production was determined by phenotypic and genotypic methods. Clonal relatedness among the isolates was studied by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). Genetic environment of these isolates was assessed by the presence of integrons and gene cassettes. Transformation experiments were done, and plasmids of these isolates were characterized by stability testing and incompatibility testing. Subsequently, a change in the ongoing antibiotic policy was adopted, and corresponding changes in the behaviour of these isolates studied. Results: During the period from August 2011 to January 2013, 46 isolates of monoclonal ESBL K. pneumoniae were obtained from different neonates and four similar environmental isolates were studied. Multidrug-resistant ESBL isolates harboured both blaCTXM-15 and blaSHV-5. The dfr and aac-6’ resistant genes were found in gene cassettes. A 50 kb plasmid belonging to IncFIIA group was detected in all the isolates which was transferable and stable. The emergence and regression of the outbreaks coincided with antibiotic usage in the NICU, with widespread empirical use of cefotaxime being responsible for their persistence in the environment. Interpretation & conclusions: The study indicates that empirical use of third generation cephalosporins may promote the emergence, persistence, and dissemination of resistant isolates in the hospital environment. Periodic review of antibiotic policy is necessary for rationalized use of antibiotics. © 2016, Indian Council of Medical Research. All rights reserved.
Occurrence of co-existing bla VIM-2 and bla NDM-1 in clinical isolates of Pseudomonas aeruginosa from India
(BioMed Central Ltd., 2016) Deepjyoti Paul; Debadatta Dhar; Anand Prakash Maurya; Shweta Mishra; Gauri Dutt Sharma; Atanu Chakravarty; Amitabha Bhattacharjee
Background: bla VIM-2 harboring Pseudomonas aeruginosa has been reported worldwide and considered as the most prevalent metallo-β-lactamase after NDM which are found horizontally transferable and mostly associated with integron gene cassettes. The present study investigates the genetic background, transmission dynamics as well as stability of bla VIM-2 in clinical isolates of P. aeruginosa harbor bla NDM-1 as well which were collected from October 2012 to September 2013. Methods: Two P. aeruginosa strains harboring bla VIM-2 along with bla NDM-1 were isolated from Silchar Medical College and Hospital, India. Genetic environment of these resistance determinants was determined and transferability was checked by transformation and conjugation assay which was further confirmed by Southern hybridization. Replicon typing was performed to determine the incompatibility group of the resistant plasmid and their stability was checked by serial passage method. Antimicrobial susceptibility pattern of the isolates was determined and their clonal relatedness was checked by pulsed field gel electrophoresis. Results: bla VIM-2 was found to be horizontally transferable through an Inc F type plasmid of approximately 30 kb in size. bla VIM-2 was found to be associated with integron gene cassette and was flanked by two different types of cassette arrays. Both the isolates were co-harboring bla NDM-1 which was carried within Inc N type of plasmid with an approximate 24 kb in size and associated with ISAba125 in their upstream region. Reduced susceptibility rate as well as high MIC range was observed in case of wild strains and transformants carrying bla VIM-2 and bla NDM-1. Conclusions: The detection of this co-existence of multiple carbapenem resistance genes in this part of world is worrisome and further investigation is required in order to trace the source and to initiate proper treatment option. © 2016 The Author(s).
Prebiotics: A new hope against antibiotic associated diarrhea
(Bentham Science Publishers B.V., 2014) Tuhina Banerjee; Amitabha Bhattacharjee
With the everincreasing problem of multidrug resistance worldwide, concerns are growing regarding use of alternative compounds to supplement or modify the actions of antibiotics. Along with drug resistance, antibiotics also provide a number of side effects, diarrhea being a very prominent one. Antibiotic associated diarrhea (AAD) is difficult to manage and therefore concepts like ‘probiotics’ have gained importance. In this respect, ‘prebiotics’, which are ‘food’ to ‘feed’ the healthy colonic flora, is an upcoming concept. Because antibiotics alter the normal intestinal flora, controlling the composition of the flora could be truly beneficial. Prebiotics are short chain carbohydrates that can alter the intestinal microbial flora to one rich in bifidobacteria and lactobacilli, the organisms that constitute ‘balanced healthy flora’ and resist gut colonizations by pathogenic flora and infections. The approach seems reasonable. Moreover, prebiotic compounds can be easily incorporated into foodstuffs unlike probiotics. Despite the availability of many natural compounds with prebiotic activity, only inulin and fructo-oligosaccharides have successfully met the criteria to be labeled as prebiotics with substantial evidence. Therefore, it is much early to suppose that prebiotics will markedly change the fate of AADs, even though their potential to restore gut microbial balance is definite. Continuous research studying the effects of more such compounds is required to substantiate the several physiological benefits of prebiotics. © 2014 Bentham Science Publishers.
Presence of different beta-lactamase classes among clinical isolates of Pseudomonas aeruginosa expressing AmpC beta-lactamase enzyme
(Journal of Infection in Developing Countries, 2010) Supriya Upadhyay; Malay R. Sen; Amitabha Bhattacharjee
Introduction: Infections caused by Pseudomonas aeruginosa are difficult to treat as the majority of isolates exhibit varying degrees of beta-lactamase mediated resistance to most of the beta-lactam antibiotics. It is also not unusual to find a single isolate that expresses multiple β-lactamase enzymes, further complicating the treatment options. Thus the present study was designed to investigate the coexistence of different beta-lactamase enzymes in clinical isolates of P. aeruginosa. Methodology: A total of 202 clinical isolates of P. aeruginosa were tested for the presence of AmpC beta-lactamase, extended spectrum beta-lactamase (ESBL) and metallo beta-lactamase (MBL) enzyme. Detection of AmpC beta-lactamase was performed by disk antagonism test and a modified three-dimensional method, whereas detection of ESBL was done by the combined disk diffusion method per Clinical and Laboratory Standards Institute (CLSI) guidelines and MBL were detected by the Imipenem EDTA disk potentiation test. Results: A total of 120 (59.4%) isolates were confirmed to be positive for AmpC beta-lactamase. Among them, 14 strains (7%) were inducible AmpC producers. Co-production of AmpC along with extended spectrum beta-lactamase and metallo beta-lactamase was reported in 3.3% and 46.6% isolates respectively. Conclusion: The study emphasizes the high prevalence of multidrug resistant P. aeruginosa producing beta-lactamase enzymes of diverse mechanisms. Thus proper antibiotic policy and measures to restrict the indiscriminative use of cephalosporins and carbapenems should be taken to minimize the emergence of this multiple beta-lactamase producing pathogens © 2010 Upadhyay et al.
Resistance plasmid: The key to the adaptation of pathogenic microorganisms in hospital environments
(Nova Science Publishers, Inc., 2023) Jayalaxmi Wangkheimayum; Tuhina Banerjee; Pue Rakshit; Nargis Alom Choudhury; Amitabha Bhattacharjee
Persistence of resistance pathogens in the nosocomial environment is a key driver of health-care associated infections. Resistance plasmids propagate within and across various species of bacteria to express a multidrug resistant phenotype. They carry diverse types of resistance genes that affect both narrow and broad host ranges. In the Indian subcontinent, the IncX plasmid type is an emerging potential genetic vehicle for the lateral expression of New-Delhi Metallo beta lactamase (blaNDM) among various pathogenic bacteria such as Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Proteus mirabilis, and Escherichia coli. This plasmid might have the advantage to disseminate to a broader host range within the hospital environment. Furthermore, blaNDM has been associated with at least 20 different types of plasmids, mostly IncFIB, IncFII, IncA/C (IncC), IncX3, IncH, and IncL/M. These plasmids can transfer, replicate, and persist within a new host to make it more favorable and adaptable for the host. This adapted plasmid helps the bacteria to survive against a wide range of antibiotics. Tracking this resistant plasmid can be a starting point to control infections caused by multidrug-resistant pathogens. This chapter provides an insight into the adaptation of broad-host-range IncP and IncX3 plasmid types under various antibiotic exposures within the hospital settings and their epidemiological significance as genetic vehicles. This understanding can help in combating the risk factors for transmission by restricting their spread in healthcare settings. © 2023 Nova Science Publishers, Inc.