Vasanthakumari Neela

Putra University, Malaysia, Putrajaya, Putrajaya, Malaysia

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Publications (44)83.3 Total impact

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    ABSTRACT: The prevalence and spread of mupirocin and antiseptic resistance among colonizing and infectious Staphylococcus aureus were determined. S. aureus isolated from anterior nares and infection sites of patients hospitalized in the largest tertiary care referral hospital in Malaysia was investigated for mupirocin and antiseptic susceptibility testing, and for PCR detection of mupA, qacA/B, and smr genes. Twelve isolates showed resistance to mupirocin by disk diffusion, of which 10 (3.8%) harbored the mupA gene. Minimum inhibitory concentrations (MICs) ranged from 64 to 768 μg/ml for mupA positive and below 46 μg/ml for negative isolates. The mupA was more common among ST239 isolates (70%). The qacA/B was carried in 67 out of 95 methicillin-resistant Staphylococcus aureus (MRSA) (70.5%) and 3 out of 164 methicillin-susceptible Staphylococcus aureus (MSSA) (1.8%), while smr was carried in 6 out of 95 MRSA (6.3%) strains. MICs ranged from 3.9 to 15.6 μg/ml for benzethonium chloride (BTC) and benzalkonium chloride (BKC), and from 10.3 to 20.7 μg/ml for chlorhexidine digluconate (CHG). Isolates with qacA/B and smr or qacA/B alone showed higher MIC (20.7 μg/ml for CHG and 15.6 μg/ml for BTC and BKC) than the isolates that lacked antiseptic resistance genes (10.3 μg/ml for CHG and 3.9 μg/ml for BTC and BKC). In 16 cases, ST239 was isolated from the infection site and the nares simultaneously, and shared identical resistance patterns (qacAB or qacAB+smr), suggesting possible endogenous infection. Spread of low-level mupirocin resistance expressing ST239 MRSA and high-level resistance expressing emerging ST1, co-existing with antiseptic-resistant genes showing elevated MICs, should be monitored for effective infection control.
    Microbial drug resistance (Larchmont, N.Y.) 05/2014; · 1.99 Impact Factor
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    ABSTRACT: Cinnamomum species have been widely used in many traditional systems of medicine around the world. In the Malaysian Traditional System of Medicine, the leaves, stem bark and stem wood of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum have been used to treat wound infections. To study the antibacterial effects of C. iners, C. porrectum, C. altissimum and C. impressicostatum against common bacteria found in would infections with primary focus on methicillin - resistant Staphylococcus aureus (MRSA). The crude extracts from the leaves, stem - bark and stem - wood of C. iners, C. porrectum, C. altissimum and C. impressicostatum were obtained using sequential extraction with hexane, ethylacetate, methanol and water. The volatile oils were obtained by hydro-distillation. The antibacterial activities of extracts were investigated using disk diffusion assays and broth microdilution assays. The volatile oils obtained from the stem - bark of C. altissimum, C. porrectum and C. impressicostatum have shown significant antibacterial activity against a wide range of Gram positive and Gram negative bacteria including MRSA. A few test extracts have shown better activity against MRSA as compared to Methicillin Sensitive Staphylococcus aureus (MSSA). Amongst all the test extracts, C. impressicostatum stem - bark water extract produced the largest inhibition zone of 21.0mm against MRSA while its inhibition zone against MSSA was only 8.5mm. The minimum inhibitory concentration (MIC) of this extract against MRSA was 19.5μgmL(-1) and the corresponding minimum bactericidal concentration (MBC) was 39.0μgmL(-1). This study has scientifically validated the traditional use of Cinnamomum species in treating wound infections. Of high scientific interest was the observation that the antibacterial effect of C. impressicostatum stem - bark crude water extract against MRSA was significantly higher than its effect against MSSA suggesting that the extract contains a compound(s) with higher specific neutralising activity against the drug resistance markers of MRSA.
    Journal of ethnopharmacology 03/2014; · 2.32 Impact Factor
  • Renjan Thomas, Rukman Awang Hamat, Vasanthakumari Neela
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    ABSTRACT: Stenotrophomonas maltophilia, which is still defined as an organism of limited pathogenicity, has risen prominently as a nosocomial pathogen. Despite the increase in the spectrum of clinical syndromes associated with S. maltophilia, very little is known about the extracellular enzymes profile, pigment production and motility patterns which may have potential roles in pathogenesis. In this study, we screened and compared an array of extracellular enzymes in S. maltophilia collected from invasive and non-invasive clinical specimens by substrate plate assays. We also grouped the isolates as device related and non-device related and compared the enzyme profile. Our study showed all clinical isolates irrespective of source produced substantial levels of enzymes assayed, produced melanin and exhibited swimming and swarming motility pattern. These data suggests clinical isolates of S. maltophila is a reservoir for pathogenic potential enzymes.
    Virulence 01/2014; 5(2). · 2.79 Impact Factor
  • Memórias do Instituto Oswaldo Cruz 01/2014; 109:1-4. · 1.36 Impact Factor
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    ABSTRACT: Although analysis of toxin-antitoxin (TA) systems can be instructive, to date, there is no information on the prevalence and identity of TA systems based on a large panel of Acinetobacter baumannii clinical isolates. The aim of the current study was to screen for functional TA systems among clinical isolates of A. baumannii and to identify the systems' locations. For this purpose, we screened 85 A. baumannii isolates collected from different clinical sources for the presence of the mazEF, relBE and higBA TA genes. The results revealed that the genes coding for the mazEF TA system were commonly present in all clinical isolates of A. baumannii. Reverse transcriptase-polymerase chain reaction analysis showed that transcripts were produced in the clinical isolates. Our findings showed that TA genes are prevalent, harboured by chromosomes and transcribed within A. baumannii. Hence, activation of the toxin proteins in the mazEF TA system should be investigated further as an effective antibacterial strategy against this bacterium.
    Memórias do Instituto Butantan 01/2014; 109(2014):1-4.
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    ABSTRACT: Enterococcus, a Gram-positive facultative anaerobic cocci belonging to the lactic acid bacteria of the phylum Firmicutes, is known to be able to resist a wide range of hostile conditions such as different pH levels, high concentration of NaCl (6.5%), and the extended temperatures between 5(°)C and 65(°)C. Despite being the third most common nosocomial pathogen, our understanding on its virulence factors is still poorly understood. The current study was aimed to determine the prevalence of different virulence genes in Enterococcus faecalis and Enterococcus faecium. For this purpose, 79 clinical isolates of Malaysian enterococci were evaluated for the presence of virulence genes. pilB, fms8, efaAfm, and sgrA genes are prevalent in all clinical isolates. In conclusion, the pathogenicity of E. faecalis and E. faecium could be associated with different virulence factors and these genes are widely distributed among the enterococcal species.
    TheScientificWorldJournal. 01/2014; 2014:623174.
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    ABSTRACT: Peritonitis still remains a serious complication with high rate of morbidity and mortality in patients on CAPD. Rapid and accurate identification of pathogens causing peritonitis in a CAPD patient is essential for early and optimal treatment. The aim of this study was to use 16S rRNA and ITS gene sequencing to identify common bacterial and fungal pathogens directly from the peritoneal fluid without culturing. Ninety one peritoneal fluids obtained from 91 different patients on CAPD suspected for peritonitis were investigated for etiological agents by 16S rRNA and ITS gene sequencing. Data obtained by molecular method was compared with the results obtained by culture method. Among the 45 patients confirmed for peritonitis based on international society of peritoneal dialysis (ISPD) guidelines, the etiological agents were identified in 37(82.2%) samples by culture method, while molecular method identified the etiological agents in 40(88.9%) samples. Despite the high potential application of the 16S rRNA and ITS gene sequencing in comparison to culture method to detect the vast majority of etiological agents directly from peritoneal fluids; it could not be used as a standalone test as it lacks sensitivity to identify some bacterial species due to high genetic similarity in some cases and inadequate database in Gene Bank. However, it could be used as a supplementary test to the culture method especially in the diagnosis of culture negative peritonitis.
    Tropical biomedicine 12/2013; 30(4):602-7. · 0.92 Impact Factor
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    ABSTRACT: The prevalence of methicillin resistant Staphylococcus aureus (MRSA) and methicillin sensitive Staphylococcus aureus (MSSA) carriage among poultry and poultry farmers in Malaysia is largely unknown. In the current investigation, chickens and chicken farmers from 30 chicken farms were screened for MRSA and S. aureus carriage. The genetic characteristics of the isolates were determined through multi locus sequence typing (MLST), Staphylococcus protein A (spa) typing and virulent gene profiling. The outcome of the study showed lack of MRSA and extremely low S. aureus prevalence (n=7 of 503, 1.4%) among chicken flocks and the poultry farmers in Malaysia. Staphylococcus aureus isolates belonged to 4 sequence types (ST): ST97 (spa type t359), ST1179 (t359), ST 692 (t2247) and ST188 (t189). It can be concluded that MRSA/MSSA prevalence is very low among chicken and chicken farmers, human and chicken cross transmission of S. aureus does not seem to be a threat in Malaysia.
    Iranian Journal of Veterinary Research 11/2013; 14(2):226-231. · 0.16 Impact Factor
  • International Conference on Natural Products and Health 2013 NPH 2013,, Classroom 1, School of Biological Sciences, Nanyang Technological University, Singapore; 09/2013
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    Renjan Thomas, Vasanthakumari Neela, Rukman Awang Hamat
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    ABSTRACT: Stenotrophomonas maltophilia plays an important role as an opportunistic pathogen in immunocompromised individuals. Despite its clinical implication, the true knowledge regarding the pathogenicity of these bacteria remains unclear. Various methods have been employed to prove this bacterium to be pathogenic. However, the debate whether S. maltophilia is a true pathogen or a colonizer still remains unanswered as effective killing was not seen in earlier experiments with different animal models of infection (Denton et al., 1998; Adamak et al., 2011; Pompilo et al., 2011). Study by Rouf et al. (2011) on murine lung infection model illustrated that different strains of mice exhibited different outcome for S. maltophilia infection. Strains such as A/J and DBA/2 were permissive for clinical isolates of S. maltophilia and showed higher levels of pro-inflammatory cytokines. In contrast, BALB/c and C57BL/6 strains were non-permissive for S. maltophilia. While Huang et al. (2009) showed nematotoxic activity by environmental S. maltophilia strain against free-living nematode, Panagrellus redivivus, and plant-parasitic nematode, Bursaphelenchus xylophilus.
    Journal of Medical Microbiology 08/2013; · 2.30 Impact Factor
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    ABSTRACT: Fifteen sequences with stop codons have been obtained in the course of standard methicillin-resistant Staphylococcus aureus (MRSA) spa typing. In nine of those sequences, stop codons occurred due to nonsense G to T and A to T transversions. G to T transversions would appear to be frequent in the spa gene, mostly due to symmetric mutational AT-pressure in the whole S. aureus genome and due to replication-associated mutational pressure characteristic of lagging strands of the "chromosome". A to T transversions would appear to be frequent in the spa gene mostly due to transcription-associated mutational pressure. Relative to other S. aureus genes, short repeats in spa are enriched by nonsense sites for G to T and A to T transversions; the probability of being a nonsense site for A to T transversion is high in that part of spa coding region. 13 out of 15 (87 %) of the sequences with stop codons were obtained from strains isolated from patients with generalized S. aureus infection. Truncation of spa at its C-terminus is predicted to result in a protein that possesses functional IgG binding domains unable to be linked to the cell wall. This is discussed in light of the known fact that extracellular spa is a strong virulence factor involved in immune evasion.
    Research in Microbiology 07/2013; · 2.89 Impact Factor
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    ABSTRACT: We developed a time-saving and cost-efficient Pulsed Field Gel Electrophoresis (PFGE) method for the typing of Stenotrophomonas maltophilia by modifying the conventional procedures. Our modifications related to the cell suspension preparation, lysis of bacterial cells in plugs, washing steps, and consumption of restriction enzyme. Although few rapid PFGE protocols on Gram-negative bacteria are available, the use of comparatively large amounts of costly reagents prompted us to look for other alternative. Hence, by considering the speed, simplicity, and relatively low cost, the modified protocol may be of more practical value than other established protocols in investigating S. maltophilia nosocomial outbreaks.
    Journal of microbiological methods 06/2013; · 2.43 Impact Factor
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    ABSTRACT: BACKGROUND: Group B Streptococcus (GBS) is a leading cause of infections such as meningitis and septicemia in neonates and pregnant women; however the significance of invasive GBS disease has not been clearly defined in non-pregnant adults. METHODS: We reviewed the hospital records of 18 cases with GBS bacteremia who attended the Universiti Kebangsaan Malaysia Medical Centre from June 2010 to October 2011. We analyzed the clinical findings of both bacteremic adults and neonates and compared them to previous studies of GBS bacteremia. Serotyping was done by latex agglutination test using 10 distinct antisera (Ia, Ib, and II-IX). RESULTS: During the period of 1 year and 4 months, there were 18 patients with GBS bacteremia. Five cases occurred in neonates, one in a parturient woman, and 12 in other adults. All neonates with bacteremia were males and two of them were premature. Septicemia was the most common clinical presentation in neonates. They were treated with intravenous (IV) penicillin G and gentamicin. The adults included nine men (69%) and four women (31%). Their mean age was 60 years and all patients had more than two underlying conditions. The most common clinical syndrome was pneumonia (n=6, 46.5%). The others were peritonitis (n=3, 23.1%), primary bacteremia (n=2, 15.5%), septic arthritis (n=2, 15.5%), skin and soft tissue infection (n=1, 7.7%), meningitis (n=1, 8%), urinary tract infection (n=1, 8%), and intravascular device infection (n=1, 7.7%). Cardiovascular diseases (n=7, 53.8%) were the most common underlying conditions, and diabetes mellitus (n=5, 38.5%) was second. The other co-morbid conditions were hyperlipidemia (n=3, 23.1%), renal disease (n=3, 23.1%), liver disease and/or alcohol abuse (n=3, 23.1%), autoimmune disease or immunosuppressive condition (n=2, 15.5%), malignancy (n=2, 15.5%), respiratory disease (n=1, 8%), and postpartum condition (n=1, 8%), as well as miscellaneous conditions including intravenous drug abuse, HIV infection, and trauma (n=2, 15.5%). Polymicrobial bacteremia was found in five (45.4%) cases and Staphylococcus aureus was the most common concurrent bacterial isolate. Of the 18 GBS isolates in both adults and neonates, serotype Ia was predominant (38.9%), followed by VI (27.8%), V (11.1%), and III (5.5%); the remaining 16.7% were non-typeable. CONCLUSIONS: GBS bacteremia is a significant problem and is associated with serious underlying disease, which may result in a high rate of mortality, not only in neonates and pregnant women, but also in non-pregnant adults.
    International journal of infectious diseases: IJID: official publication of the International Society for Infectious Diseases 02/2013; · 2.17 Impact Factor
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    ABSTRACT: One hundred and twenty methicillin-resistant Staphylococcus aureus (MRSA) isolated from cancer and non-cancer patients in Saudi Arabia were investigated for antibiotic resistance, virulence determinants and genotypes. The majority of MRSA isolates from cancer (n = 44, 73.3 %) and non-cancer patients (n = 34, 56.7 %) were multi-resistant to more than four classes of antibiotics. Virulence gene profiling showed that all strains were commonly positive for adhesin genes, except ebps and bbp genes, which were not detected in any isolate. Although the presence of adhesin genes varied slightly among MRSA isolates from cancer and non-cancer patients, these variations were not found to be statistically significant. In contrast, the presence of the toxin genes seb, sec, seg and sei was significantly elevated in MRSA strains isolated from cancer patients. Multilocus sequence typing (MLST) detected six and nine sequence types (STs) among isolates from cancer and non-cancer patients, respectively. Using spa typing, 12 and 25 types were detected, including four new types. The ability of different MRSA clones to become multi-resistant and their ability to acquire different virulence factors may contribute to their success as pathogens in individual groups of patients.
    European Journal of Clinical Microbiology 01/2013; · 3.02 Impact Factor
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    ABSTRACT: The in vitro antibacterial and antibiofilm activity of chlorogenic acid against clinical isolates of Stenotrophomonas maltophilia was investigated through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill and biofilm assays. A total of 9 clinical S. maltophilia isolates including one isolate resistant to trimethoprim/sulfamethoxazole (TMP/SMX) was tested. The inhibition zone sizes for the isolates ranged from 17-29 mm, while the MIC and MBC values ranged from 8-16 µg mL 1 and 16-32 µg mL 1. Chlorogenic acid appeared to be strongly bactericidal at 4x MIC, with a 2 log reduction in viable bacteria at 10 h. In vitro antibiofilm testing showed a 4 fold reduction in biofilm viability at 4x MIC compared to 1x MIC values (0.085 < 0.397 A 490 nm) of chlorogenic aid. The data from this study support the notion that chlorogenic acid has promising in vitro antibacterial and antibiofilm activities against S. maltophilia.
    BioMed Research International 12/2012; 2013. · 2.88 Impact Factor
  • Electrophoresis 11/2012; · 3.26 Impact Factor
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    ABSTRACT: Group B beta-hemolytic streptococcus (GBS) sepsis is a serious bacterial infection in neonates, with significant morbidity and mortality. We report here a neonate with late onset GBS infection manifesting as a urinary tract infection (UTI) in an infant presenting with prolonged neonatal jaundice. The pathogenesis of this late onset is postulated.
    The Southeast Asian journal of tropical medicine and public health 11/2012; 43(6):1470-3. · 0.61 Impact Factor
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    ABSTRACT: DNase activity is a key test in the identification of Stenotrophomonas maltophilia. Delay in the production of DNase enzyme by some strains of S. maltophilia makes the routinely used DNA-HCL or DNA toluidine blue agar methods less sensitive. The recently reported DNase tube test was modified with the addition of 20 mM CaCl2 to detect DNase activity in S. maltophilia. The modified method showed 100% positivity in 12 hrs.
    Journal of Medical Microbiology 09/2012; 6:1792-1794. · 2.30 Impact Factor
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    ABSTRACT: We investigated the potential of USA300 MRSA emergence in Malaysia by examining 268 MSSA isolates from both community (110) and healthcare (158) settings. Nine isolates from both the environments were similar to the USA300 MRSA background based on MLST, spa and PFGE type. These results underscore the importance of continued surveillance to monitor the emergence of USA300 MRSA in Malaysia.
    Tropical biomedicine 09/2012; 29(3):429-33. · 0.92 Impact Factor
  • Yun Khoon Liew, Vasanthakumari Neela
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    ABSTRACT: MRSA-ST9-t4358 from pigs and pig handlers were analysed for exoproteins profiles. Similar protein patterns with variation in protein spot intensity were observed. No significant variation among the protein profiles indicates that transmission of MRSA-ST9 from pig to human or vice versa, do not strongly alter the gene expression patterns. Indirectly, virulence factors that acquired from pig environment might have chance to be expressed in human host.
    Indian Journal of Microbiology 09/2012; 52(3):507-9. · 0.46 Impact Factor