Diphtheroids-Important Nosocomial Pathogens
Introduction: Diphtheroids are defined as aerobic, nonsporulating, pleomorphic Gram-positive bacilli which are more uniformly stained than Corynebacterium diphtheriae, lack the metachromatic granules and are arranged in a palisade manner. They are usually commensals of the skin and mucous membra...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
JCDR Research and Publications Private Limited
2016-12-01
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| Series: | Journal of Clinical and Diagnostic Research |
| Subjects: | |
| Online Access: | https://jcdr.net/articles/PDF/9043/19098_CE[Ra1]_F(RK)_PF1(GU_RO)_PFA(AK)_PF2(PAG).pdf |
| Summary: | Introduction: Diphtheroids are defined as aerobic, nonsporulating, pleomorphic Gram-positive bacilli which are
more uniformly stained than Corynebacterium diphtheriae, lack
the metachromatic granules and are arranged in a palisade
manner. They are usually commensals of the skin and mucous
membranes. They differ from C.diphtheriae in biochemical reactions as well as in toxin production. Since, they are usually
found as commensals on the skin, they are often considered
as mere contaminants when isolated from clinical samples.
However, there are increasing reports of these organisms being
associated with various infections. Hence, we felt the need
to study the common species associated with infections and
know the properties of these organisms which are otherwise
considered as mere laboratory contaminants.
Aim: To identify the various species of diphtheroids isolated
as pure growth from clinical specimens whose Gram’s smear
revealed numerous inflammatory cells with Gram positive bacilli
and had clinical evidence.
Materials and Methods: A total of 100 isolates of Gram-positive
bacilli from 16,242 clinical samples received in the Microbiology
Department of Kasturba Medical College were considered for
this study from Dec 2013-Dec 2014.
Gram-positive bacilli which were seen in the smear along with pus
cells, isolated as pure growth and reported as “Corynebacterium
spp having clinical significance” were taken for this study while
those which were reported as ‘Probable skin contaminants’
were excluded from this study. Species identification of Grampositive bacilli was done by biochemical reactions. Antibiotic
susceptibility test was done by Kirby-Bauer disk diffusion
method. Biofilm production was done by the microtitre plate
method of O’Toole and Kolter and statistical analysis was done
by using proportion test and Chi-square test.
Results: Various species of diphtheroids were isolated from
different clinical specimens. C. pseudotuberculosis, C. renale,
C. ulcerans, C. striatum, C. minutissimum, Corynebacterium
haemolyticum isolated from catheter tips, sputum, tracheostomy
secretions and wound infections were highly resistant to many
antibiotics while isolates from blood namely C. pseudotuberculosis,
C. minutissimum, C. ulcerans and C. renale were nearly sensitive
to most of them. It was also interesting to note that there was an
increased rate of biofilm production in these isolates.
Conclusion: Corynebacterium pseudotuberculosis, Corynebacterium ulcerans, Corynebacterium renale, Corynebacterium
bovis, Corynebacterium striatum, Corynebacterium minutissimum,
Corynebacterium pseudodiphtheriticum and Corynebacterium
haemolyticum may survive in the form of biofilms in hospitals
and cause multidrug resistant infections. Hence, we need to
judiciously identify these organisms, find their antimicrobial
susceptibility, treat them and thus prevent infections in
hospitals. |
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| ISSN: | 2249-782X 0973-709X |