1.Prevalence of macrolide resistance and in vitro activities of six antimicrobial agents against clinical isolates of Streptococcus pneumoniae from a multi-center surveillance in Malaysia
Jayakayatri Jeevajothi Nathan ; Niazlin Mohd Taib ; Mohd Nasir Mohd Desa ; Siti Norbaya Masri ; Rohani Md Yasin ; Farida Jamal ; Sreenivasa Rao Sagineedu ; Arunkumar Karunanidhi
The Medical Journal of Malaysia 2013;68(2):119-124
The in vitro activities of 6 antimicrobial agents against
clinical isolates of Streptococcus pneumoniae
(pneumococci) were investigated and the erythromycin
minimum inhibitory concentrations (MICs) were correlated
with the two major macrolide resistance determinants,
mef(A) and erm(B). MICs of commonly used antibiotics as
well as the presence of macrolide resistance determinant
genes in all isolates were tested. Seventy one
pneumococcal isolates collected at Institute for Medical
Research (IMR) were included in this study. Phenotypic
characterization, MIC determination using E-test strips and
polymerase chain reactions for antibiotic resistance
determination were included. Among the isolates, 25 (35.2%)
isolates were erythromycin susceptible, 3 (4.2%) were
intermediate and 42 (60.6%) were resistant. Fifty three
isolates (74.7%) were found with mef(A) alone, 15 (21.1%)
isolates with erm(B) + mef(A) combination and 3 (4.2%)
isolates with none of the two genes. The in vitro activity of penicillin, amoxicillin clavulanic acid, ceftriaxone and
cefotaxime is superior to trimethoprim-sulfamethoxazole
and erythromycin. In conclusion, pneumococcal isolates in
this study were highly susceptible to penicillin with very low MICs. However, a very high prevalence rate of erythromycin resistance was observed. Erythromycin resistant S.pneumoniae isolates with both mef(A) and erm(B) showed very high MICs ≥256 μg/mL.
2.Antimicrobial susceptibilities and random amplified polymorphic DNA-PCR fingerprint characterization of Candida glabrata, Candida parapsilosis and Candida rugosa from two major hospitals in Kuala Lumpur, Malaysia
Madhavan, P. ; Chong, P.P ; Farida, J. ; Fauziah, O. ; Cheah, Y.K. ; Arunkumar Karunanidhi, A. ; Ng, K.P.
Tropical Biomedicine 2019;36(1):183-193
The purpose of this study is to characterize 3 non-albicans Candida spp. that were
collected from two major hospitals in a densely populated area of Kuala Lumpur for their
susceptibilities to azole and genetic background. Fifteen non-albicans Candida clinical isolates
in two major hospitals in Kuala Lumpur area of Malaysia were collected by convenience
sampling during 2007 and 2010. The genetic diversity of 15 non-albicans Candida species
comprising C. glabrata (n = 5), C. parapsilosis (n = 5) and C. rugosa (n = 5) were assessed by
RAPD-PCR typing. Strains were initially identified using biochemical tests and CHROMagar
Candida medium. Fluconazole and voriconazole susceptibilities were determined by E-test
method. Commercial kits were used for DNA extraction and amplification with RAPD primers
(OPA02, OPA03 and OPA08). PCR conditions were optimized and simultaneous identification
was possible by agarose gel electrophoresis of PCR products and the bands obtained were
analyzed using BioNumerics Applied Maths v.6.6 software. The RAPD primers used in this
study generated 100% polymorphic profile. Cluster analysis using the RAPD-PCR profile showed
12.5-25% similarity among the strains. The genetic diversity was based on the strain
susceptibility towards both the azoles, site of isolation and place according to their unique
banding patterns. In contrast, strains susceptible to azoles were found to be genetically
similar with clonal dissimilarity. The use of OPA02, OPA03 and OPA08 primers in differentiating
non-albicans Candida spp. underscores the higher resolution of RAPD-PCR as a reliable tool
for strain/species level differentiation.
3.Antifungal and antibiofilm activity of Persian shallot (Allium stipitatum Regel.) against clinically significant Candida spp.
Arunkumar Karunanidhi ; Ehsanollah Ghaznavi-Rad ; Jayakayatri Jeevajothi Nathan ; Fazlin Mohd Fauzi ; Leslie Thian Lung Than ; Mallikarjuna Rao Pichika ; Rukman Awang Hamat ; Vasanthakumari Neela
Tropical Biomedicine 2018;35(3):815-825
Candida species are the most common cause of fungal infections that range from
non-life-threatening mucocutaneous illness to life-threatening invasive processes that may
involve virtually any organ. Such a broad range of infections requires an equally broad range
of therapeutic approach. Persian shallot (Allium stipitatum Regel.) is a medicinal plant that
has been widely used in tradition Persian medicine for various ailments. Allium stipitatum is
also used in modern medicine and has been reported to have a range of health benefits
including antibiotic (antifungal) properties. The present study assessed the in vitro
anticandidal and antibiofilm potential of hexane (ASHE) and dichloromethane (ASDE) extracts
of Allium stipitatum (Persian shallot) against planktonic and biofilm forms of 5 medically
important Candida spp. Antifungal activity was assessed by disk diffusion, minimum inhibitory
concentration (MIC), minimum fungicidal concentration (MFC) and time-kill assay. The
antibiofilm activity of ASHE and ASDE against reference strain C. albicans ATCC 14053 was
determined by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide]
reduction assay. The zone of inhibition ranged from 22 to 40 mm, while the MICs ranged from
8 to 32 μg mL-1. The MFCs of ASHE and ASDE were in the range of 16 to 32 μg mL-1 each
respectively. Time-kill kinetics showed that both extracts were strongly fungicidal against
planktonic cultures of C. albicans with ~ 1.45 log reduction in CFU at 4 h post-treatment
(hpt). In addition, both ASHE and ASDE were shown to inhibit preformed C. albicans biofilms
in a concentration-dependent manner. The results demonstrated that ASHE and ASDE were
broad-spectrum in action, and could be developed as a promising alternative to synthetic
antifungals in controlling infections due to Candida spp. of clinical significance.