Antimicrobial Activity of Nigella sativa Seeds Extract Against Carbapenem and Colistin Resistant Gram Negative Bacilli in Khartoum State

Abstract Introduction: One of the most serious issues in medicine is increasing resistance of Gram negative bacilli to antimicrobial agents especially broad spectrum antibiotics such as carbapenems and colistins. This fact is associated with higher mortality and morbidity rates, prolonged hospital stays and increased treatment related costs.Medicinal plants appeared to be the best alternative source for new antimicrobial drugs.. Nigella sativa is an herbaceous plant whose seeds have beenused for centuries for treatment of various ailments, including infectious diseases, and is an important drug of Unani Medicine Narrated Abu Hurairah, “I heard Allah‟s Apostle saying, „There is healing in black cumin for all diseases except death‟.” Objective: This study aimedto detect antibacterial Activity of Nigella sativa extract against carbapenem and colistin resistant gram negative bacilli from Khartoum State Method: Cross-sectional study and laboratory based study was carried out on 90 isolates from different specimenninety types of pathogenic bacteria were isolated and identified using Gram stain, biochemical reactions and tested for their susceptibility to Carbapenem and colistin antibiotic was performed for all Gram-negative bacilli isolates, then detection of carbapenemase enzyme production for the resistant isolates was performed using modified Hodge test and EDTA combing test. Those were resistant to carbapenem and colistin were tested for their sensitivity to Nigellasativa extracts. Result: The isolated Gram-negative bacilli comprising of 41(45.6%)E.coli, 25 (27.8%) Klebsiella species, 14(15.6%)Proteus species, 4(4.4%) Pseudomonas species, 3(3.3%) Enterobacter species and 3(3.3%) Citrobacter species. . Carbapenem (Imipenem and meropenem) susceptibility testing showed that 31% of Gram-negative rods isolates were Carbapenem resistant. Modified hodge test positive result (63%) EDTA combing test positive result(69%). Colistin susceptibility testing showed that 16.7% of Gram-negative rods isolates were Colistin resistant. Methanol extractof Nigella sativa showed antibacterial activity all clinical isolates with highest effect in concentration 50.

Topic Page

I اٌَح

Dedication II

Acknowledgment III

Abstract IV

Abstract (Arabic) V

Table of contents VI

List of Tables X

List of Figures XI

List of Abbreviation XII

CHAPTER ONE

INTRODUCTION

1.1. Introduction 1

1.2. Rationale 3

1.3. Objectives 5

1.3.1. General objective 5

1.3.2. Specific objectives 5

CHAPTER TWO

LITERATURE REVIEW

2.1. Carbapenems 6

2.1.1. Mode of action of Carbapenems 6

2.1.2. Mode of resistant to Carbapenems 6

2.1.3. Treatment options for carbapenem resistant bacteria 6

VII

2.1.3.1 .Polymyxins 6

2.1.3.2. Tigecycline 7

2.1.3.3. Aztreonam 7

2.1.3.4. Fosfomycin 7

2.1.3.5. Aminoglycosides 7

2.1.3.6. Combination Therapy 7

2.2. Colistin 7

2.2.1. Mechanism of action of colistin 9

2.2.2. The mechanism of resistance to colistin 9

2.3. Medical plant 10

2.4. Plant extraction 10

2.4.1. Extraction procedures 11

2.4.1.1. Plant tissue homogenization 11

2.4.1.2. Serial exhaustive extraction 11

2.4.1.3. Soxhlet extraction 11

2.4.1.4. Maceration 12

2.4.1.5. Decoction 12

2.4.1.6. Infusion 12

2.4.1.7. Digestion 12

2. 4.1.8. Percolation 13

2.4.1.9. Sonication 13

VIII

2.5. Antimicrobial Properties of Medicinal Plants 14

2.6. Nigella sativa 14

2.6.1. Taxonomic classification 15

2.6.2. Botanical description 15

2.6.3. Distribution 16

2.6.4. Common names 16

2.6.5. Chemical constituents 16

2.6.6. Medicinal uses 16

2.7. Previous studies 17

CHAPTER THREE

MATERIALS AND METHODS

3.1. Study design 23

3. 2.Study area and study duration 23

3.3. Study population 23

3.4. Sample size 23

3.5. Inclusion criteria 23

3.6. Exclusion criteria 23

3.7. Laboratory investigations 23

3.7.1. Gram`s stain 24

3.7.2 Oxidase test 24

3. 7.3.kligler iron agar 24

3.7.4. Indole test 25

IX

3.7.5. Urease test 25

3.7.6. Citrate utilization test: 25

3.7.7. Motility 26

3.7.8. Sensitivity testing 26

3.7.9. Phenotypic detection of carbapenemases 26

3.7.9.1. Modified Hodge Test 26

3.7.9.2. EDTA Disk synergy test 27

3. 7. 10. Preservation and storage of isolated organisms 28

3. 7.11. Collection and identification of plant material 28

3.7.12. Preparation of the extracts 28

I3.8. Ethical considerations 29

3.11. Data analysis 29

CHAPTER FOUR

RESULTS

Results 30

CHAPTER FIVE

DISCUSSION

5.1. Discussion 37

5.2. Conclusions 38

5.3. Recommendations 38

References 40

Appendixes 46