Investigation of the Potential Association between Clustered Regularly Interspersed Short Palindromic Repeats (CRISPR) and Antibiotic Resistance Pattern of Bacterial Strains Isolated from Medical Waste and Environmental Water

Md Shahariar Alam,Md Ismail Hosen,Anik Paul,M Anwar Hossain,Sajib Chakraborty,A K M Mahbub Hasan,Taibur Rahman

doi:10.4236/ojmm.2018.82002

Abstract

Enterobacteriaceae are important human pathogens that cause many food and waterborne illness. Rapid emergence of multi-drug resistant bacteria in Bangladesh has become a serious problem. Phage-host interaction is now considered as the major driving force for the conversion of non-pathogenic bacteria to pathogenic ones. Evolution of highly pathogenic and antibiotic resistant bacteria largely depends upon the horizontal gene transfer by means of plasmid, megaplasmid and bacteriophages. Conversely, bacteria may acquire a novel defence mechanism called CRISPR (Clustered regularly interspersed short palindromic repeats) that can restrict horizontal transfer of plasmids and bacteriophages to limit the spread of antibiotic resistance genes among bacterial species. In this study, twenty bacterial strains were isolated from water of different medical waste and Buriganga river. Therefore, CRISPR locus was investigated following various biochemical and molecular analysis of those bacterial isolates. Identification of the bacterial isolates was conducted by Polymerase Chain Reaction (PCR) based assay of 16S rDNA extracted from those isolated strains. Results indicated that most strains were identified as Proteus mirabilis and Citrobacter freundii which mainly cause septicemia, and pneumonia in human. Thereafter, antibiogram of these strains was performed by using 11 different antibiotic discs where bacterial isolates from medical drainage system showed more resistant to antibiotics than the river water. In this study, CRISPR locus was also investigated within the genome of the isolated bacterial stains but unexpectedly, we did not find any CRISPR locus in their genome. In conclusion, we confirm that multi-drug resistant bacterial strains are devoid of CRISPR locus suggesting a possible negative association between CRISPR locus and antibiotic resistance. Further studies to pinpoint are required to elucidate the underlying mechanism of the association between CRISPR and antibiotic resistance in these isolated strains.

Highlights

Prevalence of infectious diseases is very high in developing countries like Bangladesh
Horizontal transfer of genes by mean of plasmid and bacteriophages has often been linked to the survival advantages of the host bacterial strains
In contrast bacterial strains are known to acquire defense mechanism that can potentially restrict the events of horizontal gene transfer

Summary

Introduction

Prevalence of infectious diseases is very high in developing countries like Bangladesh. This might be due to lack of awareness, proper hygiene, poverty and change of climate. Many pathogenic bacteria of Enterobacteriaceae family, for instance Proteus, Citrobacter, cause various infectious diseases among the people which are mainly transmitted through contaminated food and water. Proteus are important opportunistic pathogens that cause urinary tract and septic infections in human. Hospital Acquired Infection (HAI) is caused by these bacteria [1] and they generally found in animals, birds, reptiles, soil sewage, polluted water and human intestine. Citrobacter can cause a wide spectrum of infections, such as infections in the urinary tract, respiratory tract, wounds, bone, peritoneum, endocardium, meninges, and bloodstream in aged (≥65 years) individuals or in immunocompromised patients. The rate mortality by Citrobacter infections is very high from 2.0% to 17.7% [3] [4]

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Conclusion