Application of Bacteriophage in Nosocomial infection control, A new concept to disinfect Hospital environment
Date
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Biotechnology
Abstract
Introduction: Health care associated infections (HAIs) are one of the important public
health problems which might result in significant rise in mortality and morbidity,
predominantly in immune compromised patients of Intensive Care Unit (ICU). A study
showed that in the Asian region, risks of HAIs have been estimated to be 2-20 times
higher than in developed countries up to 25% of hospitalized patients having acquired
infection (Ling et al., 2015) and also a report shows that in United States, roughly 9.2 out
of every 100 patients acquire a nosocomial infection, according to Healthline and among
them also some HAIs is quite serious and potentially life-threatening. The common
bacteria causing nosocomial infections include Pseudomonas aeruginosa, klebsiella
pneumonia, Acinetobacter baumanii, Enterococci etc. (Khan, Baig, & Mehboob, 2017).
Therefore, disinfectants like alcohols, hypochlorite, hydrogen peroxide, amyl phenol,
glutaraldehyde etc. are widely used in hospital to kill these organisms which cause NAs
but sometimes these chemical disinfectants might be hazardous, irritants and toxic to us
and environment. Among many alternatives, bacteriophage mediated bio-control of the
pathogenic bacteria is considering as one of the best options. Our objective of the study
is to isolate, identify the pathogenic bacteria from the hospital environment and
evaluate the efficacy of newly isolated lytic bacteriophage to minimize the bacterial load
on hospital fomites.
Methodology: The study time period of this research was 6 months and, in this study,
we isolated phage against Pseudomonas aeruginosa bacteria collected from ICU of Teku
hospital. Then most potent phage was characterized morphologically and
Physiochemically. Burst size was obtained from one step growth curve. Intraspecific and
interspecific host range was assessed by spot assay. During this research work, we used
sterile fomite cloth pieces and marble tile as they are most potent sources were bacteria
reside. Firstly, we contaminate the fomites and tiles with Pseudomonas aeruginosa
bacteria then after we used Pseudomonas aeruginosa phage to decontaminate those
cloths and tile.
Result: Altogether 16 bacterial strain, 4 Pseudomonas aeruginosa and 12
Staphylococcus aureus were confirmed by Gram staining and Biochemical test and
among them 2 Pseudomonas aeruginosa strains and 5 Staphylococcus aureus strains
were found to be Carbapenem resistance and Multi Drug Resistant (MDR) respectively.
Total six bacteriophages against Pseudomonas aeruginosa were isolated from different
sewage samples. And one of the most potent phage P4 was characterized
morphologically and physiochemically. Burst size of the phage was found to be 28
virions per bacterium. Protein profiling was done by SDS-PAGE where protein band
between 20-250Kda were found and Phage P4 belongs to order Caudovirales and family
Siphoviridae. Similarly, Phage was found to tolerate temperature of 70°C for 20
minutes, pH 3-12, exhibiting multiple host range as well. Decontamination assay was
done on the sterile fabric cloth which showed that the P4 phage having MOI value 1
showed higher rate of decontamination with log reduction of 1 and p-value (0.002) i.e.,
significant. Further Comparison was done between P4 phage and normal disinfectant
Phenol where we found that single phage has more disinfectant rate than phenol.
xi
Similarly, time period up to which bacteriophage can show their effectivity as
disinfectant was also done and it showed highest level of effectivity up to 6 hours at MOI
1 with the CFU/ml log reduction of 1.
Conclusion: The result from the present thesis reveals several characteristics of the
bacteriophage (P4), for instance, effective lytic capability, multiple host range, and
stability in wide range of pH and temperature. Higher rate of decontamination with the
log reduction of 1 CFU/ml and p-value (0.002) was showed by P4 phage having MOI
value of 1. While doing comparison single phage have more disinfectant rate than
normal disinfectant & P4 phage can show its highest level of effectivity up to 6 hrs at
MOI 1.
Keywords: Nosocomial Infection, disinfectant, Pseudomonas aeruginosa, bacteriophage,
decontamination