Silpi Basak

Antimicrobial efficacy of five essential oils against oral pathogens: An in vitro study

Objectives: This study was aimed to find out the minimum inhibitory concentration (MIC) of five essential oils against oral pathogens and to find out the minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) of five essential oils against oral pathogens. Materials and Methods: The antimicrobial activities by detecting MIC and MBC/MFC of five essential oils such as tea tree oil, lavender oil, thyme oil, peppermint oil and eugenol oil were evaluated against four common oral pathogens by broth dilution method. The strains used for the study were Staphylococcus aureus ATCC 25923, Enterococcus fecalis ATCC 29212, Escherichia coli ATCC 25922 and Candida albicans ATCC 90028. Results: Out of five essential oils, eugenol oil, peppermint oil, tea tree oil exhibited significant inhibitory effect with mean MIC of 0.62 ± 0.45, 9.00 ± 15.34, 17.12 ± 31.25 subsequently. Mean MBC/MFC for tea tree oil was 17.12 ± 31.25, for lavender oil 151.00 ± 241.82, for thyme oil 22.00 ± 12.00, for peppermint oil 9.75 ± 14.88 and for eugenol oil 0.62 ± 0.45. E. fecalis exhibited low degree of sensitivity compared with all essential oils. Conclusion: Peppermint, tea tree and thyme oil can act as an effective intracanal antiseptic solution against oral pathogens.

Detection of Blastocystis hominis: a controversial human pathogen

Blastocystis hominis has been reclassified as a protozoan parasite. Its role as a human pathogen is somewhat controversial. There has been a dramatic increase in the frequency of B. hominis infection in association with diarrhea especially in immunocompromised hosts like AIDS patients, travelers, homosexuals, day care children, animal handlers especially zoo keepers, etc. Recent reports suggest that B. hominis is an emerging pathogen; hence, we have undertaken this study to detect B. hominis from stool samples of patients attending our hospital. About 200 stool samples were tested by light microscopic examination, for observing wet mounts with saline and Lugol’s iodine. Permanent staining of fecal smear by Gram’s staining and modified acid fast staining was done. The stool sample which was microscopically positive for B. hominis was cultured on Lowenstein–Jensen’s (LJ) medium. In one patient, the vacuolated form of B. hominis was observed in wet mount with saline preparation of stool sample. This was very clearly seen in wet mount with Lugol’s iodine. In Gram’s stained preparation, also the vacuolated form was observed. Detection of B. hominis was not possible by modified acid fast staining. B. hominis was also grown on LJ medium which is an egg-containing medium. Clinical microbiology laboratories should start screening of stool samples for B. hominis as it is an emerging pathogen.

MRSA--too many hurdles to overcome: a study from Central India.

Methicillin-resistant Staphylococcus aureus (MRSA) are commonly associated with nosocomial infections and are usually resistant to many antibiotics. This study describes the prevalence of MRSA strains and their antibiogram in a tertiary care hospital in Central India. The detection of MRSA was done by a cefoxitin (30 µg) disc diffusion test. Antibiotic sensitivity tests were done as per the Clinical and Laboratory Standards Institute guidelines 2006. Of the 280 S. aureus strains studied: 145 (51.8%) strains were MRSA; 51 (35.2%) MRSA strains were inducible clindamycin resistant; and all (100%) MRSA strains were resistant to penicillin and sensitive to vancomycin and linezolid. In order to detect the MRSA strains, cefoxitin disc diffusion tests should be used routinely in any microbiology laboratory to enable prompt treatment for the patient.

Multidrug Resistant and Extensively Drug Resistant Bacteria: A Study

Background and Objective. Antimicrobial resistance is now a major challenge to clinicians for treating patients. Hence, this short term study was undertaken to detect the incidence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR) bacterial isolates in a tertiary care hospital. Material and Methods. The clinical samples were cultured and bacterial strains were identified in the department of microbiology. The antibiotic susceptibility profile of different bacterial isolates was studied to detect MDR, XDR, and PDR bacteria. Results. The antibiotic susceptibility profile of 1060 bacterial strains was studied. 393 (37.1%) bacterial strains were MDR, 146 (13.8%) strains were XDR, and no PDR was isolated. All (100%) Gram negative bacterial strains were sensitive to colistin whereas all (100%) Gram positive bacterial strains were sensitive to vancomycin. Conclusion. Close monitoring of MDR, XDR, or even PDR must be done by all clinical microbiology laboratories to implement effective measures to reduce the menace of antimicrobial resistance.

Biofilms: A Challenge to Medical Fraternity in Infection Control

Microbes have been characterized as planktonic, free-floating single cells. The morphological and physiological properties of microbes have been described as they grow in nutritionally rich culture media. Earlier very little thought have been given how microbes survive in the environment. But, the fact is, in natural environment, microbes are commonly found to be attached to surfaces as biofilms. Hence, the formation of surface attached microbial cells known as biofilms open a new horizon to study the micro-organisms.

Pseudomonas Aeruginosa and Newer β-Lactamases: An Emerging Resistance Threat

Infact, the rising trend of developing resistance to multiple antibiotics in microbes, leading to therapeutic failure is a serious problem of global magnitude. P.aeruginosa, Methicillin Resistant Staphylococcus aureus (MRSA), Vancomycin resistant Enterococci(VRE), Glycopeptide Intermediate Staphylococcus aureus (GISA), Glycopeptide Resistant Staphylococcus aureus (GRSA), Acinetobacter baumani, Stenotrophomonas maltophila etc. need special attention as they are commonly isolated from Health Care Associated Infections(HAI) and belong to Multidrug resistant Organism (MDRO) i.e. they are resistant to one or more classes of antibiotics (Harrison & Lederberg, 1998). P. aeruginosa is responsible for 10-15% of nosocomial infections worldwide. The β-lactam group of antibiotics which include Penicillins, Cephalosporins, Monobactams and Carbapenems are mainly used to treat infections caused by Gram negative bacteria. The widespread use of antibiotics put tremendous selective pressure on bacteria which develop new mechanisms to escape the lethal action of the antibiotics. These infections are difficult to treat because of emergence of newer β-lactamases such as Extended Spectum β-lactamases (ESBL), AmpCβlactamases and Carbapenemases. The β-lactamases inactivate β-lactam antibiotics by cleaving the structural β-lactam ring. Failure to detect these enzymes producing strains has contributed to their uncontrolled spread in Health Care setup and therapeutic failure.

A Simple Method for Demonstrating the Giardia Lamblia Trophozoite

INTRODUCTION Giardia lamblia is a flagellated protozoan parasite of man. Only 2 stages i.e. the trophozoite and the cyst forms are observed in the life cycle of Giardia. The Giardia infection is acquired from drinking water or by eating food which is contaminated with cysts. The symptoms of the Giardia infection are foul smelling diarrhoea, flatulence, steatorrhoea, etc. Stool samples from the patients are examined for the detection of the motile trophozoites and cysts. As the trophozoites disintegrate rapidly, the stool sample should be observed within 15 minutes of its passage. Hence, we developed a staining method to stain the Giardia trophozoite permanently. MATERIALS AND METHODS Smears of the stool samples were prepared and they were fixed with methanol. The staining was done by using a 1% methylene blue solution. RESULTS All the 15 known Giardia lamblia trophozoite positive samples were also found to be positive by the Methylene blue staining. The Giardia lamblia cysts could not be stained by this method. 20 stool samples were used as negative controls. CONCLUSION We developed the methylene blue staining for demonstrating the trophozoite of Giardia, which is a very simple permanent staining method. The slides can be kept for a permanent record.

Evaluation of Antimicrobial Activity of Two Endodontic Sealers: Zinc Oxide with Thyme Oil and Zinc Oxide Eugenol against Root Canal Microorganisms—An in vitro Study

Aim The present study was aimed to find out and compare the antimicrobial effect of the paste containing zinc oxide cement mixed with thyme oil (ZO + Th oil) with that of the paste containing zinc oxide and eugenol (ZO + E) against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa, common root canal pathogens of deciduous teeth. Materials and methods An in vitro antimicrobial effect was carried out by the agar diffusion method. The ZO + Th oil paste was filled in the punched holes of Mueller Hinton agar at two equidistant points. The same was followed for ZO + E paste. For 24 hours, all the plates were incubated at a temperature of 37°C. The inhibition zones in millimeters around the wells were calculated. There were 6 times repetitions of the test for each microorganism. Data were tabulated and analyzed statistically using one-way analysis of variance (ANOVA) and Tukey’s post hoc comparison test. Level of significance for the tests was 5%. Results Zones of bacterial inhibition were highest for ZO + Th oil paste against the pathogenic microorganisms S. aureus, followed by E. coli, E. faecalis, P. aeruginosa while for ZO + E paste, the decreasing order against pathogenic microorganisms was E. coli, S. aureus, E. faecalis, and P. aeruginosa. Statistically significant difference was found in both the pastes, ZO + Th oil paste and ZO + E paste. Conclusion ZO + Th oil paste showed higher levels of antimicrobial effect against the root canal pathogens. How to cite this article: Thosar NR, Chandak M, Bhat M, Basak S. Evaluation of Antimicrobial Activity of Two Endodontic Sealers: Zinc Oxide with Thyme Oil and Zinc Oxide Eugenol against Root Canal Microorganisms—An in vitro Study. Int J Clin Pediatr Dent 2018;11(2):79-82.

Infection Control Practices in Health Care Set-Up

In India, Egypt, Palestine and Greece, the concept of hospital with hygienic practices was present as early as 500 BC. Later, hospitals became overcrowded as it were only meant for military personnel [1]. From 18th Century onwards new hospitals were established for civilians also. The transmission of infections in the hospital were also known to mankind since the sick were housed together for treatment. But no epidemiological data or surveillance system was available. But the enormity of the problem of Hospital Acquired Infections in pre-Lister era can be best understood by the writing of John Bell in 1801 who described the concept of “Hospital Gangrene” [2]. Lord Joseph Lister first used carbolic acid as an antiseptic in 1865 and published his work in 1867 which started the antiseptic era and he has been remembered as “Father of Antiseptic Surgery”.