Seema Irfan

Bio: Seema Irfan is an academic researcher from Aga Khan University Hospital. The author has contributed to research in topics: Drug resistance & Salmonella typhi. The author has an hindex of 14, co-authored 58 publications receiving 3306 citations. Previous affiliations of Seema Irfan include Integral University & Aga Khan University.

Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study

Abstract: Summary Background Gram-negative Enterobacteriaceae with resistance to carbapenem conferred by New Delhi metallo-β-lactamase 1 (NDM-1) are potentially a major global health problem. We investigated the prevalence of NDM-1, in multidrug-resistant Enterobacteriaceae in India, Pakistan, and the UK. Methods Enterobacteriaceae isolates were studied from two major centres in India—Chennai (south India), Haryana (north India)—and those referred to the UK's national reference laboratory. Antibiotic susceptibilities were assessed, and the presence of the carbapenem resistance gene bla NDM-1 was established by PCR. Isolates were typed by pulsed-field gel electrophoresis of XbaI-restricted genomic DNA. Plasmids were analysed by S1 nuclease digestion and PCR typing. Case data for UK patients were reviewed for evidence of travel and recent admission to hospitals in India or Pakistan. Findings We identified 44 isolates with NDM-1 in Chennai, 26 in Haryana, 37 in the UK, and 73 in other sites in India and Pakistan. NDM-1 was mostly found among Escherichia coli (36) and Klebsiella pneumoniae (111), which were highly resistant to all antibiotics except to tigecycline and colistin. K pneumoniae isolates from Haryana were clonal but NDM-1 producers from the UK and Chennai were clonally diverse. Most isolates carried the NDM-1 gene on plasmids: those from UK and Chennai were readily transferable whereas those from Haryana were not conjugative. Many of the UK NDM-1 positive patients had travelled to India or Pakistan within the past year, or had links with these countries. Interpretation The potential of NDM-1 to be a worldwide public health problem is great, and co-ordinated international surveillance is needed. Funding European Union, Wellcome Trust, and Wyeth.

Phylogenetic diversity of Escherichia coli strains producing NDM-type carbapenemases

Abstract: Background The global accumulation of Escherichia coli with CTX-M extended-spectrum s-lactamases partly reflects the dissemination of clonal lineages, notably ST131 and ST405. More recently, E. coli have emerged that produce NDM carbapenemase. We sought to determine the clonal diversity of E. coli with this enzyme from English hospitals, and to compare them with isolates from Pakistan and India. Methods The 18 NDM-positive E. coli were from hospitals in England (n?=?10), Pakistan (n?=?7) and India (n?=?1). Isolates were compared by phylogenetic grouping, multilocus sequence typing and PFGE of XbaI-digested DNA. Isolates were screened by PCR for acquired AmpC genes, blaCTX-M, and the 16S rRNA methylase genes armA and rmtC. Results Most of the isolates belonged to phylogenetic groups B1 (n?=?9) or D (n?=?7); two were group A and none was group B2. Nine isolates from England and Pakistan belonged to the B1 lineage ST101, with seven of these clustering at >77% similarity by PFGE. Other lineages included ST405 (n?=?3, group D), ST648 (n?=?3, group D), the ST23 complex (one each of ST90 and ST410, both group A) and ST156 (n?=?1, group D). Sixteen of 18 isolates had a group 1 CTX-M gene, 13 had a CIT-type acquired AmpC, and 16 had either or both of armA and rmtC. Conclusions The E. coli isolates producing NDM-1 carbapenemase belonged to six sequence types and included diverse clonal lineages. Nevertheless, isolates of B1-ST101 accounted for half the collection, and included isolates from both England and Pakistan. None of the isolates belonged to ST131 or to phylogroup B2.

Emergence of Carbapenem resistant Gram negative and vancomycin resistant Gram positive organisms in bacteremic isolates of febrile neutropenic patients: A descriptive study

Abstract: Background This study was conducted to evaluate drug resistance amongst bacteremic isolates of febrile neutropenic patients with particular emphasis on emergence of carbapenem resistant Gram negative bacteria and vancomycin resistant Enterococcus species.

Impact of infection control activities on the rate of needle stick injuries at a tertiary care hospital of Pakistan over a period of six years: an observational study

Abstract: Accidental exposure to blood and body fluids is frequent among health care workers. They are at high risk of nosocomial transmission of blood borne pathogens due to injuries caused by used sharps. We are reporting impact of surveillance and educational program on the rate of needle stick injuries among health care workers at a tertiary care hospital in Pakistan. At Aga Khan University Hospital sharp injuries are reported to infection control office. To reduce these incidents a quality improvement project was inducted in the year 2005. Health care workers were educated; surveillance data from 2002 to 2007 was analyzed and compared with various risk factors. During study period 1382 incidents were reported. Junior doctors sustained highest number of injuries (n = 394; 28.5%) followed by registered nurses (n = 283; 20.4%). Highest number of incidents was reported during blood collection (19%). An increasing trend was observed in the pre intervention years (2002–04). However noticeable fall was noted in the post intervention period that is in year 2006 and 2007. Major decline was noted among nurses (from 13 to 5 NSI/100 FTE/year). By relating and comparing the rates with various activities directly linked with the use of syringes a significant reduction in incidents were found including; hospital admissions (p-value 0.01), surgeries and procedures performed (p = 0.01), specimens collected in the laboratory (p = 0.001) and patients visits in clinics (p = 0.01). We report significant reduction in needle stick injuries especially during post intervention study period. This is being achieved by constant emphasis on improving awareness by regular educational sessions, implemented as a quality improvement project.

Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: A microbiological and molecular biological study

Abstract: Summary Background Until now, polymyxin resistance has involved chromosomal mutations but has never been reported via horizontal gene transfer. During a routine surveillance project on antimicrobial resistance in commensal Escherichia coli from food animals in China, a major increase of colistin resistance was observed. When an E coli strain, SHP45, possessing colistin resistance that could be transferred to another strain, was isolated from a pig, we conducted further analysis of possible plasmid-mediated polymyxin resistance. Herein, we report the emergence of the first plasmid-mediated polymyxin resistance mechanism, MCR-1, in Enterobacteriaceae. Methods The mcr-1 gene in E coli strain SHP45 was identified by whole plasmid sequencing and subcloning. MCR-1 mechanistic studies were done with sequence comparisons, homology modelling, and electrospray ionisation mass spectrometry. The prevalence of mcr-1 was investigated in E coli and Klebsiella pneumoniae strains collected from five provinces between April, 2011, and November, 2014. The ability of MCR-1 to confer polymyxin resistance in vivo was examined in a murine thigh model. Findings Polymyxin resistance was shown to be singularly due to the plasmid-mediated mcr-1 gene. The plasmid carrying mcr-1 was mobilised to an E coli recipient at a frequency of 10 −1 to 10 −3 cells per recipient cell by conjugation, and maintained in K pneumoniae and Pseudomonas aeruginosa . In an in-vivo model, production of MCR-1 negated the efficacy of colistin. MCR-1 is a member of the phosphoethanolamine transferase enzyme family, with expression in E coli resulting in the addition of phosphoethanolamine to lipid A. We observed mcr-1 carriage in E coli isolates collected from 78 (15%) of 523 samples of raw meat and 166 (21%) of 804 animals during 2011–14, and 16 (1%) of 1322 samples from inpatients with infection. Interpretation The emergence of MCR-1 heralds the breach of the last group of antibiotics, polymyxins, by plasmid-mediated resistance. Although currently confined to China, MCR-1 is likely to emulate other global resistance mechanisms such as NDM-1. Our findings emphasise the urgent need for coordinated global action in the fight against pan-drug-resistant Gram-negative bacteria. Funding Ministry of Science and Technology of China, National Natural Science Foundation of China.

Antibiotic resistance—the need for global solutions

Abstract: The causes of antibiotic resistance are complex and include human behaviour at many levels of society; the consequences affect everybody in the world. Similarities with climate change are evident. Many efforts have been made to describe the many different facets of antibiotic resistance and the interventions needed to meet the challenge. However, coordinated action is largely absent, especially at the political level, both nationally and internationally. Antibiotics paved the way for unprecedented medical and societal developments, and are today indispensible in all health systems. Achievements in modern medicine, such as major surgery, organ transplantation, treatment of preterm babies, and cancer chemotherapy, which we today take for granted, would not be possible without access to effective treatment for bacterial infections. Within just a few years, we might be faced with dire setbacks, medically, socially, and economically, unless real and unprecedented global coordinated actions are immediately taken. Here, we describe the global situation of antibiotic resistance, its major causes and consequences, and identify key areas in which action is urgently needed.

Molecular mechanisms of antibiotic resistance.

Abstract: Antibiotic-resistant bacteria that are difficult or impossible to treat are becoming increasingly common and are causing a global health crisis. Antibiotic resistance is encoded by several genes, many of which can transfer between bacteria. New resistance mechanisms are constantly being described, and new genes and vectors of transmission are identified on a regular basis. This article reviews recent advances in our understanding of the mechanisms by which bacteria are either intrinsically resistant or acquire resistance to antibiotics, including the prevention of access to drug targets, changes in the structure and protection of antibiotic targets and the direct modification or inactivation of antibiotics.

Global spread of Carbapenemase-producing Enterobacteriaceae.

Abstract: Carbapenemases increasingly have been reported in Enterobacteriaceae in the past 10 years. Klebsiella pneumoniae carbapenemases have been reported in the United States and then worldwide, with a marked endemicity at least in the United States and Greece. Metallo-enzymes (Verona integron–encoded metallo-β-lactamase, IMP) also have been reported worldwide, with a higher prevalence in southern Europe and Asia. Carbapenemases of the oxacillinase-48 type have been identified mostly in Mediterranean and European countries and in India. Recent identification of New Delhi metallo-β-lactamase-1 producers, originally in the United Kingdom, India, and Pakistan and now worldwide, is worrisome. Detection of infected patients and carriers with carbapenemase producers is necessary for prevention of their spread. Identification of the carbapenemase genes relies mostly on molecular techniques, whereas detection of carriers is possible by using screening culture media. This strategy may help prevent development of nosocomial outbreaks caused by carbapenemase producers, particularly K. pneumoniae.

Antibiotics and Bacterial Resistance in the 21st Century

Abstract: Dangerous, antibiotic resistant bacteria have been observed with increasing frequency over the past several decades. In this review the factors that have been linked to this phenomenon are addressed. Profiles of bacterial species that are deemed to be particularly concerning at the present time are illustrated. Factors including economic impact, intrinsic and acquired drug resistance, morbidity and mortality rates, and means of infection are taken into account. Synchronously with the waxing of bacterial resistance there has been waning antibiotic development. The approaches that scientists are employing in the pursuit of new antibacterial agents are briefly described. The standings of established antibiotic classes as well as potentially emerging classes are assessed with an emphasis on molecules that have been clinically approved or are in advanced stages of development. Historical perspectives, mechanisms of action and resistance, spectrum of activity, and preeminent members of each class are discussed.