Bushra Chaudary (2009-VA-232)

Modulation Of Antibiotics Resistance Pattern In Escherichia Coli By Different Plant - 2015. - 76p.;

Escherichia coli (E. coli) is Gram negative microorganism belonging to family
Enterobacteriaceae. It is part of normal micro flora of gastrointestinal tract of human and all
warm blooded animals (Kaper et al. 2004). Escherichia coli is source of many infectious diseases
in human as well as in animals. Common E. coli infections are enteritis, urinary tract infection,
septicemia and neonatal meningitis. In pets and farm animals, E. coli is associated with diarrhea
(Allocati et al. 2013). Poultry industry is facing huge annual losses due to infection of avian
Pathogenic E. coli (APEC) in broilers (Oosterik et al. 2014). E. coli causes a variety of
syndromes in poultry including yolk sac infection, respiratory tract infection, swollen head
syndrome, septicemia and cellulitis (Buys et al. 1989)
Antibiotics are chemical agents which inhibit the microbial growth and used to eradicate
infections. Mechanisms of action of antibiotics provide a base to categorize antimicrobial agents.
Most important classes of antibiotics act as inhibitors of cell wall synthesis, protein synthesis
(tetracyclines and macrolides), nucleic acid synthesis (fluoroquinolones), metabolic pathway
(trimethoprim-sulfamethoxazole) and cell membrane (polymyxins). Bacteria may have intrinsic
or acquired resistance to antimicrobials (Tenover 2006).
Urinary tract infections are mostly caused by E.coli. Antibiotics generally used for the treatment
of E. coli infections include ampicillin, nitrofurntion, cephalosporin, sulphonamides
(trimethoprim-sulfamethoxazole) and quonolones (neladixic acid, ofloxacine, ciprofloxacin and
levofloxacine) (Lin and Lin 2010).
Extended use and misuse of antibiotics lead to the development of resistant bacteria. Resistant
E. coli strains are common source of hospital born and community acquired infections. Ease of
international travelling is one of the major spreading factor for antibiotic resistance. Resistant
bacteria got opportunity to move from one geographical area to another (van der Bij and Pitout
2012). New strains of E. coli resistant to carbapenems (New Delhi metallo-β-lactamase 1 (NDM-
1) are major global health issue (Kumarasamy et al. 2010). Antibiotic resistance has become a
serious public health problem. Currently, world is facing great difficulty in treatment of many
infectious disease of human and animals. One of the reasons of treatment failure is emergence of
resistant bacteria (Levy 2002).
To develop new strategies for treatment of infectious diseases, it is necessary to understand the
mechanisms of resistance. Efflux pump inhibitors, enzymatic degradations and alteration of
target sites are major strategies by which bacteria acquire or develop resistance to antibiotics
(Sibanda and Okoh 2007).
Scientists are looking for alternatives of antibiotics such as bacteriopheges, naturally
antimicrobial compounds and some non antimicrobial agents (Worthington and Melander 2013).
Probiotics (Lactobacillus and bifidobacterium) can be a prophylactic measures against E. coli
and may be used to treat intestinal tract infections of E. coli and other bacteria (de Vrese and
Schrezenmeir 2008).
Phytochemicals, secondary metabolites of plants, have antibacterial activity against many
pathogenic organisms. These phytochemicals in combination with antibiotics may show
synergistic effect. Phytochemicals and plant extracts can be a source of antibiotic resistancemodifying
agents (RMAs) (Abreu et al. 2012). Plant extracts shown antibacterial activity
because of phytochemicals like alkaloids, tannins, flavonoids, phenolic compounds and steroids
(Gobalakrishnan et al. 2013). Plant extracts are used as traditional medicine for the treatment of
many diseases. Plant extracts like Zingiber officinalis (Ginger) Gymnema sylvestre (Gurmar buti), Astragalus (goat’s thorn), Calotropis procera (apple of Sodom) and oputia dillenii (cactus)
have antimicrobial activity (indu et al. 2006 and Kumaar et al. 2013). Plant extracts also have
antibiotic resistance modulation potential (Mako et al. 2012).

Department of Microbiology


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