Vasanthakumari Neela

Putra University, Malaysia, Putrajaya, Putrajaya, Malaysia

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Publications (49)91.89 Total impact

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    ABSTRACT: The exoproteome of Staphylococcus aureus contains enzymes and virulence factors that are important for host adaptation. We investigated the exoprotein profiles and cytokine/chemokine responses obtained during three different S. aureus-host interaction scenarios using two-dimensional gel electrophoresis and immunoblots (2-DGE/2D-IB) combined with tandem mass spectrometry (MS/MS) and cytometric bead array (CBA) techniques. The scenarios included S. aureus bacteremia, skin and soft tissue infections (SSTIs) and healthy carriage. By 2-DGE approach, twelve exoproteins (chaperone protein DnaK (DnaK), phosphoglycerate kinase (Pgk), chaperone GroEL (GroEL), multi-sensor hybrid histidine kinase, 3-methyl-2-oxobutanoate hydroxymethyltransferase (PanB), cysteine synthase A, N-acetyltransferase, four isoforms of elongation factor Tu (EF-Tu) and one signature protein spot that could not be reliably identified by MS/MS) were found to be consistently present in more than 50% of the bacteremia isolates, while none of the SSTIs or healthy carrier isolates showed any of these proteins. By 2D-IB approach, we also identified five antigens (methionine aminopeptidase (MetAPs), exotoxin 15 (Set15), peptidoglycan hydrolase (LytM), alkyl hydroperoxide reductase (AhpC) and haptoglobin-binding heme uptake protein (HarA)) specific for SSTIs cases. The cytokine and chemokine productions varied during the course of different infection types and carriage. Monokine induced by interferon-γ (MIG) was highly stimulated in bacteremia patients when compared with SSTIs patients and healthy carriers, especially during the acute phase of infection. MIG could therefore be further explored as a potential biomarker for bacteremia. In conclusion, twelve exoproteins from bacteremia isolates, MIG production, and five antigenic proteins identified during SSTIs should be further investigated for potential use as diagnostic markers. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
    Clinical and vaccine Immunology: CVI 03/2015; 22(5). DOI:10.1128/CVI.00493-14 · 2.37 Impact Factor
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    ABSTRACT: Several studies have shown that protein expression patterns vary in unrelated bacterial strains due to genomic plasticity and gene regulation, resulting in enhanced heterogeneity in the infection potential. However, exoprotein expression patterns of closely related clonal strains have not been well characterized. Here, we used medium-range (pH 4–7) immobilized pH gradient–two-dimensional gel electrophoresis to investigate the exoproteome from closely related Staphylococcus aureus clonal isolates. Interestingly, we found that, under identical in vitro experimental conditions, a number of protein spots were uniquely present in samples from each clonal isolate irregardless of the similarity of the genotype and the same virulence gene profile. Only a few abundant invariant proteins were found among identical genotypic isolates. Our results clearly shown that heterogeneity in the exoproteome was present even among clonally related strains. We suggest that this heterogeneity may contribute to the degree of virulence even within one clonal genotype. The heterogeneity in the exoproteome of closely related S. aureus strains observed in the current study postulates that pre-existing antibodies are not very protective during recurrent infection with the same strain. Therefore, our findings underscore the importance of taking all clonally related strains into account during proteome analyses.
    Annals of Microbiology 01/2015; DOI:10.1007/s13213-015-1064-7 · 1.04 Impact Factor
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    ABSTRACT: A total of 103 group B streptococci (GBS) including 22 invasive, 21 non-invasive, and 60 colonizing isolates were collected in a Malaysian hospital (June 2010-October 2011). Isolates were characterized by conventional and molecular serotyping and analyzed for scpB, lmb, hylB, cylE, bac, bca and rib gene content. Antimicrobial susceptibility to penicillins, macrolides, lincosamides, quinolones and tetracyclines was determined using disk diffusion and the MICs for penicillin were determined by E-test. Molecular serotyping for all eight serotypes (Ia, Ib, II-VII) was in full accordance with conventional serotyping. Overall, taking CS and MS together, serotype VI was the most common capsular type (22.3 %) followed by VII (21.4 %), III (20.4 %), Ia (17.5 %), V (9.7 %), II (7.7 %) and IV (1 %). Susceptibility to beta-lactam antimicrobials was prevalent (100 %). Resistance rates for erythromycin, clindamycin and tetracycline were 23.3 %, 17.5 % and 71.8 %, respectively. PCR-virulence gene screening showed the presence of cylE, lmb, scpB and hylB in almost all the isolates while rib, bca, and bac genes were found in 29.1 %, 14.6 % and 9.7 % of the isolates. Certain genes were significantly associated with specific serotypes, namely, rib with serotypes Ia, II, III and VI; bca and bac with serotypes II and III. Furthermore, serotype Ia was significantly more common among patients with invasive infections (p < 0.01) and serotype VI isolates were significantly more common among carriers (p < 0.05). In summary, serotype distribution correlates with virulence gene content will be useful in epidemiological studies and design of vaccines.
    European Journal of Clinical Microbiology 10/2014; 34(3). DOI:10.1007/s10096-014-2265-x · 2.54 Impact Factor
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    ABSTRACT: Background: This study was undertaken to evaluate Staphylococcus aureus carriage and persistence in health sciences students at the Faculty of Medicine and Health Sciences, Universiti Putra Malaysia. Methods: Consent form and self-administered questionnaires on socio-demographics, hygienic practices, medical and medication history were distributed followed by nasal swab collection; sampling was done twice in one month interval in October and November 2013. Bacterial identification followed the standard phenotypic methods. Antibiotic susceptibility of isolates against oxacillin and cefoxitin was tested by disc diffusion method. Methicillin resistance determinant gene (mecA) was detected through polymerase chain reaction-assay. Results: S. aureus was isolated from 31.3% (60/192) and 33.3% (60/180) of the student population during the first and second sampling respectively. Among the S. aureus-positive participants, about 65% of them were persistent carrier (S. aureus was detected during both sampling exercises). Six methicillin-resistant S. aureus (MRSA) were detected (four and two isolates in the two sampling events respectively) as inferred by decreased susceptibility to oxacillin and cefoxitin and presence of mecA gene; two of the strains were from a single individual. Fisher’s exact test showed no significant correlation between carriage and the tested risk factors except for the habit of touching nose and chronic illnesses (P < 0.05), with a higher incidence of S. aureus among those associated with the two risk factors. Conclusions: As far as the limited sampling period is concerned, these findings indicate that a proportion of the student population may be at infection risk. Avoiding frequent nose-touching could be one of the preventive measures.
    Iranian Journal of Public Health 10/2014; 43(Suppl. No.3):112-116. · 0.58 Impact Factor
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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.
    07/2014; 2014:623174. DOI:10.1155/2014/623174
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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; DOI:10.1089/mdr.2013.0222 · 2.52 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; 153(3). DOI:10.1016/j.jep.2014.02.044 · 2.94 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). DOI:10.4161/viru.27724 · 3.32 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 Oswaldo Cruz 01/2014; 109(4):1-4. DOI:10.1590/0074-0276130601 · 1.57 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: 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. · 0.82 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. · 0.22 Impact Factor
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    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; DOI:10.1099/jmm.0.063230-0 · 2.27 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; DOI:10.1016/j.resmic.2013.07.003 · 2.83 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; 94(2). DOI:10.1016/j.mimet.2013.06.001 · 2.10 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; 17(9). DOI:10.1016/j.ijid.2013.01.011 · 2.33 Impact Factor
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    ABSTRACT: The typical concentration of protein loaded varies from 0.13 to 1.40 mu g/mu L for a classical silver staining method in 2DE gel. Here, we present a simple modified classical silver staining method by modifying the silver impregnation and development reaction steps. This modified method detects the protein spots at extremely low loaded concentrations, ranging from 0.0048 to 0.0480 mu g/mu L. We recommend this modified silver staining as an excellent method for the limited biological samples used for silver-stained 2DE analysis. Altogether, the protocol takes close to two days from first dimension separation to second dimension separation, followed by silver staining, scanning, and analysis.
    Electrophoresis 02/2013; 34(3). DOI:10.1002/elps.201200380 · 3.16 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; 32(6). DOI:10.1007/s10096-012-1801-9 · 2.54 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. DOI:10.1155/2013/392058 · 2.71 Impact Factor