In the past, Neisseria gonorrhoeae has developed resistance to antimicrobial agents used for its ... more In the past, Neisseria gonorrhoeae has developed resistance to antimicrobial agents used for its treatment. Consequently, extended-spectrum cephalosporins form the mainstay of treatment for gonorrhoea. Samples from 88 patients attending the sexually transmitted diseases clinics from December 2009 to January 2011 in two referral hospitals in New Delhi were studied. Antimicrobial susceptibility testing was done using the disc diffusion method as per the calibrated dichotomous sensitivity technique against the following antibiotics: penicillin (0.5 i.u.), tetracycline (10 μg), nalidixic acid (30 μg), ciprofloxacin (1 μg), spectinomycin (100 μg), ceftriaxone (0.5 μg) and cefpodoxime (10 μg) (Oxoid UK). Azithromycin (15 μg) (Oxoid, UK) was tested as per the guidelines of the Clinical and Laboratory Standards Institute. Minimum inhibitory concentrations were determined using the Etest for penicillin, tetracycline, ciprofloxacin, ceftriaxone, spectinomycin and azithromycin as per the manuf...
We report a rare occurrence of primary meningococcal polyarthritis in a 19-year-old man. The flui... more We report a rare occurrence of primary meningococcal polyarthritis in a 19-year-old man. The fluid in the elbow joint showed Gram-negative diplococci but the culture was sterile. The diagnosis was confirmed by polymerase chain reaction targeting crgA gene of Neisseria meningitidis.
Gonorrhoea is among the most frequent of the estimated bacterial sexually transmitted infections ... more Gonorrhoea is among the most frequent of the estimated bacterial sexually transmitted infections (STIs) and has significant health implications in women. The use of nucleic acid amplification tests (NAATs) has been shown to provide enhanced diagnosis of gonorrhoea in female patients. However, it is recommended that an on-going assessment of the test assays should be performed to check for any probable sequence variation occurring in the targeted region. In this study, an in-house PCR targeting opa-gene of Neisseria gonorrhoeae was used in conjunction with 16S ribosomal PCR to determine the presence of gonorrhoea in female patients attending the tertiary care hospitals. Endocervical samples collected from 250 female patients with complaints of vaginal or cervical discharge or pain in lower abdomen were tested using opa and 16S ribosomal assay. The samples were also processed by conventional methods. Of the 250 female patients included in the study, only one was positive by convention...
Poster presentations the two proportions was highly significant. We also compared BV present in L... more Poster presentations the two proportions was highly significant. We also compared BV present in LSIL group with HSIL group. BV was present in 29% cases in LSIL group compared to 45% in HSIL group (P = 0.03). The difference between the two proportions was significant. Conclusion The presence of BV was significantly higher in SIL group and was associated with the severity of SIL. The presence of BV should not deter a diagnosis of SIL but trigger a meticulous search for abnormal cells. Giant Condyloma aCuminata of BusChke and lowenstein treated suCCessfully surGiCally
Poster presentations the cycle threshold mean of the in-house assay and those of both commercial ... more Poster presentations the cycle threshold mean of the in-house assay and those of both commercial kits. Conclusion Both commercial kits allowed prompt and specific results, validated by the use of an internal amplification control. NAATs For GoNorrhoeA DiAGNosis iN WomeN: exPerieNce oF A TerTiAry cAre hosPiTAl iN NorTh iNDiA
In the absence of a single nucleic acid amplification test (NAAT) that is both highly specific an... more In the absence of a single nucleic acid amplification test (NAAT) that is both highly specific and sensitive for gonorrhoea, many have put forward the 16S-based assay as a confirmatory test for Neisseria gonorrhoeae. This study was undertaken to evaluate the performance of PCR based on 16S ribosomal gene in comparison with a porA pseudogene-based assay. The specificity of both the porA pseudogene-based PCR and 16S ribosomal gene PCR was checked against a panel of strains comprising of non N gonorrhoeae Neisseria sp (NgNS) and other gram-negative and gram-positive bacteria. The sensitivity studies were performed using different dilutions of N gonorrhoeae DNA. PCRs were also done on endocervical and urethral swab samples collected from a total of 100 female and 50 male patients presenting to sexually transmitted disease clinics, Dermatology OPD of AIIMS and Safdarjang Hospital, New Delhi, India, recruited as per inclusion criteria. PCR assay based on 16S ribosomal gene showed cross-reactivity with three of six strains of N sicca. The porA pseudogene-based PCR was highly specific. Analytical sensitivity of 16S-based ribosomal assay was more than that of porA pseudogene-based assay. In clinical samples, for female patients, sensitivity, specificity, positive predictive value and negative predictive value of 16S ribosomal assay was 100% (95% CI 51.7% to 100%), 91.5% (95% CI 83.4% to 96%), 42.9% (95% CI 18.8% to 70.4%) and 100% (95% CI 94.7% to 100%), respectively, while for the male patients it was 100% (95% CI 85% to 100%), 95.5% (95% CI 75.1% to 99.8%), 96.6% (95% CI 80.4% to 99.8%) and 100% (95% CI 80.8% to 100%), respectively. The data presented in this report supports use of 16S ribosomal assay as a screening assay only. The porA pseudogene target is highly specific for N gonorrhoeae and may be used as a supplemental assay.
Polyaniline/carbon nanotubes composite (PANI-CNT) electrochemically deposited onto indium-tin-oxi... more Polyaniline/carbon nanotubes composite (PANI-CNT) electrochemically deposited onto indium-tin-oxide (ITO) coated glass plate has been utilized for Neisseria gonorrhoeae detection by immobilizing 5'-amino-labeled Neisseria gonorrhoeae probe (aDNA) using glutaraldehyde as a cross-linker. PANI-CNT/ITO and aDNA-Glu-PANI-CNT/ITO electrodes have been characterized using scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). This bioelectrode can be used to detect N. gonorrhoeae using methylene blue (MB) as redox indicator with response time of 60 s and stability of about 75 days when stored under refrigerated conditions. DPV studies reveal that this bioelectrode can detect complementary DNA concentration from 1 x 10(-6) M to 1 x 10(-17) M with detection limit of 1.2 x 10(-17) M. Further, this bioelectrode (aDNA-Glu-PANI-CNT/ITO) exhibits specificity toward N. gonorrhoeae species and shows negative response with non-Neisseria gonorrhoeae Neisseria species (NgNS) and other gram negative bacteria (GNB).
A sequence-specific electrochemical sexually transmitted disease (STD) sensor based on self-assem... more A sequence-specific electrochemical sexually transmitted disease (STD) sensor based on self-assembled monolayer of thiolated DNA probe specific to target opa gene for detection of Gonorrhoea, a sexually transmitted disease has been fabricated. 6-Mercapto-1-hexanol (MCH) has been used as a blocking agent to facilitate oligos "stand" up at the surface, a configuration favoring subsequent DNA hybridization and to repel non-specific adsorption of undesired DNA. The results of differential pulse voltammetric studies of this STD sensor reveal low detection limit (1.0 × 10(-18)M) and a wide dynamic range (from 1.0 × 10(-6)M to 0.5 × 10(-18)M) arising due to the stable hybridization using methylene blue as an electro-active DNA hybridization indicator. The experimental results with genomic DNA, clinical patient sample of Neisseria gonorrhoeae, culture of non-N. gonorrhoeae Neisseria species (NgNS) and gram negative bacteria indicate that the fabricated sensor is specific to this STD.
Indian Journal of Sexually Transmitted Diseases and AIDS, 2009
... Diagnostic approach to gonorrhoea: Limitations Rachna Verma 1 , Seema Sood 1 , Manjubala 2 , ... more ... Diagnostic approach to gonorrhoea: Limitations Rachna Verma 1 , Seema Sood 1 , Manjubala 2 , Arti Kapil 1 , VK Sharma 3 1 Department of Microbiology, AIIMS, India 2 Regional STD Teaching, Training and Research Center, VMMC & SJH, India 3 Department of Dermatology ...
Electrochemically fabricated nano-composite film of chitosan (CH)-iron oxide (Fe 3 O 4) has been ... more Electrochemically fabricated nano-composite film of chitosan (CH)-iron oxide (Fe 3 O 4) has been used to detect gonorrhoea, a sexually transmitted disease (STD) via immobilization of biotinylated probe DNA (BDNA) using avidin-biotin coupling for rapid and specific (mismatch-discriminating) DNA hybridization. The presence of Fe 3 O 4 nanoparticles (∼18 nm) increases the electro-active surface area of the nanobiocomposite that provides desirable environment for loading of DNA with better conformation leading to increased electron transfer kinetics between the medium and electrode. The differential pulse voltammetric (DPV) studies have been conducted using BDNA/avidin/CH-Fe 3 O 4 /ITO electrode owing to the reduction of the methylene blue (MB) indicator and investigate electron transfer between MB moieties and electrode for one and two-bases mismatch. This STD biosensor is found to have a detection limit (1 × 10 −15 M) and a wide dynamic range (from 1 × 10 −16 M to 1 × 10 −6 M) using the complementary target DNA. In addition, the sensing system can be utilized to accurately discriminate complementary sequence from mismatch sequences.
STD (sexually transmitted disease, Gonorrhoea) sensor based on nucleic acid probe (from Opa, a mu... more STD (sexually transmitted disease, Gonorrhoea) sensor based on nucleic acid probe (from Opa, a multi-copy gene of Neisseria gonorrhoeae) functionalized nanostructured-polyaniline coated onto indium-tin-oxide-coated glass plate has been fabricated using avidin-biotin as cross-linking agent. This DNA functionalized electrode can specifically detect upto 0.5 × 10 −15 M of complementary target within 60 s of hybridization time at 25 • C by differential pulse voltammetry (DPV) using methylene blue as electro-active DNA hybridization indicator. This highly sensitive and specific nucleic acid functionalized nanostructured-polyaniline electrode can distinguish presence of N. gonorrhoeae from Neisseria meningitidis and Escherichia coli culture and spiked samples from the urethral swabs of the patients.
The nanocomposite based on polyaniline (PANI)-iron oxide nanoparticles (nFe 3 O 4) and multi wall... more The nanocomposite based on polyaniline (PANI)-iron oxide nanoparticles (nFe 3 O 4) and multi walled carbonnanotubes (CNT) has been fabricated onto indium tin oxide (ITO) coated glass plate via facile electrochemical synthesis of polyaniline in presence of nFe 3 O 4 (~20 nm) and CNT (20-80 nm in diameter). The results of transmission electron microscopic studies show evidence of coating of PANI and nFe 3 O 4 onto the CNT. The PANI-nFe 3 O 4-CNT/ITO nanoelectrode has been characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy studies. The biotinylated nucleic acid probe sequence consisting of 20 bases has been immobilized onto PANI-nFe 3 O 4-CNT/ITO nanoelectrode using biotin-avidin coupling. It is shown that the PANI-nFe 3 O 4-CNT platform based biosensor can be used to specifically detect bacteria (N. gonorrhoeae) at minute concentration as low as (1× 10 − 19 M) indicating high sensitivity within 45 s of hybridization time at 298 K by differential pulse voltammetry using methylene blue as electroactive indicator. This bacterial sensor has also been tested with 4 positive and 4 negative PCR amplicons of gonorrhoea affected patient samples. The results of these studies have implications towards the fabrication of a handheld device for Neisseria gonorrhoeae detection that may perhaps result in a decrease in the human immunodeficiency virus infections.
ABSTRACT The present invention relates to nucleic acid primers and probe for detection of Neisser... more ABSTRACT The present invention relates to nucleic acid primers and probe for detection of Neisseria gonorrhoeae. The use of the probe sequence for detection of N. gonorrhoeae in clinical samples (endocervical swabs in females and urethral discharge in males) has been described along with the different biomaterials to which it can be immobilized for detection purpose by the biosensor technology. In addition to its use as a detection probe, the sequence can be used as primer for in vitro amplification of N. gonorrhoeae in clinical samples. The discriminatory capacity of the unique sequence has been established by utilizing the panel of non-N. gonorrhoeae Neisseria species (NgNS) as well as other gram-negative bacteria.
Indian journal of dermatology, venereology and leprology
The pathogenesis is unknown though Torrelo et al. suggested that vaccines may induce an immune re... more The pathogenesis is unknown though Torrelo et al. suggested that vaccines may induce an immune response against specific and non-specific antigens in patients with trigger factors and that the trauma of injection may cause endothelial damage and tissue hypoxia. [1] Different treatments have been tried including potent topical corticosteroids, systemic corticosteroids and methotrexate but none has proved effective. [1] Even though no case of progression to generalized morphea or of the development of systemic symptoms has been reported, we consider it important to follow-up the patient in order to assess the symmetric growth of the limbs and detect any appearance of systemic symptoms. [4]
ABSTRACT Introduction The diagnosis of child abuse is based on a combination of child’s history, ... more ABSTRACT Introduction The diagnosis of child abuse is based on a combination of child’s history, physical findings, and when appropriate, laboratory and other tests. Overall, the diagnosis is often complicated but suspicion should always be followed by further investigations. Formulating a conclusion and reaching a diagnosis of child abuse may require the assistance and coming together of different specialities in the hospital. Case history: A seven year old girl presented to the Dermatology and Venereology OPD of a tertiary hospital in New Delhi, India with chief complaints of vaginal discharge for last 4 years. The vaginal swab(s) on Gram stain revealed numerous pus cells with GNDC, intracellular as well as extracellular. The child was treated based on clinical suspicion of gonorrhoea. However, RCUT put up from suspected colonies on modified Thayer Martin medium was positive for Neisseria meningitidis. In addition, crgA gene PCR from DNA extracted from the swab as well as the isolate was positive for N. meningitidis while opa-gene PCR for N. gonorrhoeae was negative. Although she was initially treated for suspected gonococcal infection, the clinical diagnosis was refuted by the results of culture and PCR. Discussion & conclusion: The findings of the present case emphasise the importance of careful culture techniques for isolation of organisms & their correct identification which is the cornerstone of appropriate therapy. It also drives home the necessity of using lactose in Rapid Carbohydrate Utilization Test (RCUT), which is crucial to differentiate between N. meningitidis and N. lactamica. It is also important for the laboratory (especially one that is considered a referral laboratory) to have capacity to perform molecular tests to confirm or refute presumptive findings, as was done in the present case. This observation stresses that an interdisciplinary approach appears to be a valuable tool for evaluating such children.
In the absence of a single nucleic acid amplification test (NAAT) that is both highly specific an... more In the absence of a single nucleic acid amplification test (NAAT) that is both highly specific and sensitive for gonorrhoea, many have put forward the 16S-based assay as a confirmatory test for Neisseria gonorrhoeae. This study was undertaken to evaluate the performance of PCR based on 16S ribosomal gene in comparison with a porA pseudogene-based assay. The specificity of both the porA pseudogene-based PCR and 16S ribosomal gene PCR was checked against a panel of strains comprising of non N gonorrhoeae Neisseria sp (NgNS) and other gram-negative and gram-positive bacteria. The sensitivity studies were performed using different dilutions of N gonorrhoeae DNA. PCRs were also done on endocervical and urethral swab samples collected from a total of 100 female and 50 male patients presenting to sexually transmitted disease clinics, Dermatology OPD of AIIMS and Safdarjang Hospital, New Delhi, India, recruited as per inclusion criteria. PCR assay based on 16S ribosomal gene showed cross-reactivity with three of six strains of N sicca. The porA pseudogene-based PCR was highly specific. Analytical sensitivity of 16S-based ribosomal assay was more than that of porA pseudogene-based assay. In clinical samples, for female patients, sensitivity, specificity, positive predictive value and negative predictive value of 16S ribosomal assay was 100% (95% CI 51.7% to 100%), 91.5% (95% CI 83.4% to 96%), 42.9% (95% CI 18.8% to 70.4%) and 100% (95% CI 94.7% to 100%), respectively, while for the male patients it was 100% (95% CI 85% to 100%), 95.5% (95% CI 75.1% to 99.8%), 96.6% (95% CI 80.4% to 99.8%) and 100% (95% CI 80.8% to 100%), respectively. The data presented in this report supports use of 16S ribosomal assay as a screening assay only. The porA pseudogene target is highly specific for N gonorrhoeae and may be used as a supplemental assay.
Polyaniline/carbon nanotubes composite (PANI-CNT) electrochemically deposited onto indium-tin-oxi... more Polyaniline/carbon nanotubes composite (PANI-CNT) electrochemically deposited onto indium-tin-oxide (ITO) coated glass plate has been utilized for Neisseria gonorrhoeae detection by immobilizing 5(-amino-labeled Neisseria gonorrhoeae probe (aDNA) using glutaraldehyde as a cross-linker. PANI-CNT/ITO and aDNA-Glu-PANI-CNT/ITO electrodes have been characterized using scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). This bioelectrode can be used to detect N. gonorrhoeae using methylene blue (MB) as redox indicator with response time of 60 s and stability of about 75 days when stored under refrigerated conditions. DPV studies reveal that this bioelectrode can detect complementary DNA concentration from 1 T 10 S6 M to 1 T 10 S17 M with detection limit of 1.2 T 10 S17 M. Further, this bioelectrode (aDNA-Glu-PANI-CNT/ITO) exhibits specificity toward N. gonorrhoeae species and shows negative response with non-Neisseria gonorrhoeae Neisseria species (NgNS) and other gram negative bacteria (GNB).
A sequence-specific electrochemical sexually transmitted disease (STD) sensor based on self-assem... more A sequence-specific electrochemical sexually transmitted disease (STD) sensor based on self-assembled monolayer of thiolated DNA probe specific to target opa gene for detection of Gonorrhoea, a sexually transmitted disease has been fabricated. 6-Mercapto-1-hexanol (MCH) has been used as a blocking agent to facilitate oligos "stand" up at the surface, a configuration favoring subsequent DNA hybridization and to repel non-specific adsorption of undesired DNA. The results of differential pulse voltammetric studies of this STD sensor reveal low detection limit (1.0 × 10 −18 M) and a wide dynamic range (from 1.0 × 10 −6 M to 0.5 × 10 −18 M) arising due to the stable hybridization using methylene blue as an electro-active DNA hybridization indicator. The experimental results with genomic DNA, clinical patient sample of Neisseria gonorrhoeae, culture of non-N. gonorrhoeae Neisseria species (NgNS) and gram negative bacteria indicate that the fabricated sensor is specific to this STD.
Indian Journal of Sexually Transmitted Diseases and AIDS, 2009
... Diagnostic approach to gonorrhoea: Limitations Rachna Verma 1 , Seema Sood 1 , Manjubala 2 , ... more ... Diagnostic approach to gonorrhoea: Limitations Rachna Verma 1 , Seema Sood 1 , Manjubala 2 , Arti Kapil 1 , VK Sharma 3 1 Department of Microbiology, AIIMS, India 2 Regional STD Teaching, Training and Research Center, VMMC & SJH, India 3 Department of Dermatology ...
In the past, Neisseria gonorrhoeae has developed resistance to antimicrobial agents used for its ... more In the past, Neisseria gonorrhoeae has developed resistance to antimicrobial agents used for its treatment. Consequently, extended-spectrum cephalosporins form the mainstay of treatment for gonorrhoea. Samples from 88 patients attending the sexually transmitted diseases clinics from December 2009 to January 2011 in two referral hospitals in New Delhi were studied. Antimicrobial susceptibility testing was done using the disc diffusion method as per the calibrated dichotomous sensitivity technique against the following antibiotics: penicillin (0.5 i.u.), tetracycline (10 μg), nalidixic acid (30 μg), ciprofloxacin (1 μg), spectinomycin (100 μg), ceftriaxone (0.5 μg) and cefpodoxime (10 μg) (Oxoid UK). Azithromycin (15 μg) (Oxoid, UK) was tested as per the guidelines of the Clinical and Laboratory Standards Institute. Minimum inhibitory concentrations were determined using the Etest for penicillin, tetracycline, ciprofloxacin, ceftriaxone, spectinomycin and azithromycin as per the manuf...
We report a rare occurrence of primary meningococcal polyarthritis in a 19-year-old man. The flui... more We report a rare occurrence of primary meningococcal polyarthritis in a 19-year-old man. The fluid in the elbow joint showed Gram-negative diplococci but the culture was sterile. The diagnosis was confirmed by polymerase chain reaction targeting crgA gene of Neisseria meningitidis.
Gonorrhoea is among the most frequent of the estimated bacterial sexually transmitted infections ... more Gonorrhoea is among the most frequent of the estimated bacterial sexually transmitted infections (STIs) and has significant health implications in women. The use of nucleic acid amplification tests (NAATs) has been shown to provide enhanced diagnosis of gonorrhoea in female patients. However, it is recommended that an on-going assessment of the test assays should be performed to check for any probable sequence variation occurring in the targeted region. In this study, an in-house PCR targeting opa-gene of Neisseria gonorrhoeae was used in conjunction with 16S ribosomal PCR to determine the presence of gonorrhoea in female patients attending the tertiary care hospitals. Endocervical samples collected from 250 female patients with complaints of vaginal or cervical discharge or pain in lower abdomen were tested using opa and 16S ribosomal assay. The samples were also processed by conventional methods. Of the 250 female patients included in the study, only one was positive by convention...
Poster presentations the two proportions was highly significant. We also compared BV present in L... more Poster presentations the two proportions was highly significant. We also compared BV present in LSIL group with HSIL group. BV was present in 29% cases in LSIL group compared to 45% in HSIL group (P = 0.03). The difference between the two proportions was significant. Conclusion The presence of BV was significantly higher in SIL group and was associated with the severity of SIL. The presence of BV should not deter a diagnosis of SIL but trigger a meticulous search for abnormal cells. Giant Condyloma aCuminata of BusChke and lowenstein treated suCCessfully surGiCally
Poster presentations the cycle threshold mean of the in-house assay and those of both commercial ... more Poster presentations the cycle threshold mean of the in-house assay and those of both commercial kits. Conclusion Both commercial kits allowed prompt and specific results, validated by the use of an internal amplification control. NAATs For GoNorrhoeA DiAGNosis iN WomeN: exPerieNce oF A TerTiAry cAre hosPiTAl iN NorTh iNDiA
In the absence of a single nucleic acid amplification test (NAAT) that is both highly specific an... more In the absence of a single nucleic acid amplification test (NAAT) that is both highly specific and sensitive for gonorrhoea, many have put forward the 16S-based assay as a confirmatory test for Neisseria gonorrhoeae. This study was undertaken to evaluate the performance of PCR based on 16S ribosomal gene in comparison with a porA pseudogene-based assay. The specificity of both the porA pseudogene-based PCR and 16S ribosomal gene PCR was checked against a panel of strains comprising of non N gonorrhoeae Neisseria sp (NgNS) and other gram-negative and gram-positive bacteria. The sensitivity studies were performed using different dilutions of N gonorrhoeae DNA. PCRs were also done on endocervical and urethral swab samples collected from a total of 100 female and 50 male patients presenting to sexually transmitted disease clinics, Dermatology OPD of AIIMS and Safdarjang Hospital, New Delhi, India, recruited as per inclusion criteria. PCR assay based on 16S ribosomal gene showed cross-reactivity with three of six strains of N sicca. The porA pseudogene-based PCR was highly specific. Analytical sensitivity of 16S-based ribosomal assay was more than that of porA pseudogene-based assay. In clinical samples, for female patients, sensitivity, specificity, positive predictive value and negative predictive value of 16S ribosomal assay was 100% (95% CI 51.7% to 100%), 91.5% (95% CI 83.4% to 96%), 42.9% (95% CI 18.8% to 70.4%) and 100% (95% CI 94.7% to 100%), respectively, while for the male patients it was 100% (95% CI 85% to 100%), 95.5% (95% CI 75.1% to 99.8%), 96.6% (95% CI 80.4% to 99.8%) and 100% (95% CI 80.8% to 100%), respectively. The data presented in this report supports use of 16S ribosomal assay as a screening assay only. The porA pseudogene target is highly specific for N gonorrhoeae and may be used as a supplemental assay.
Polyaniline/carbon nanotubes composite (PANI-CNT) electrochemically deposited onto indium-tin-oxi... more Polyaniline/carbon nanotubes composite (PANI-CNT) electrochemically deposited onto indium-tin-oxide (ITO) coated glass plate has been utilized for Neisseria gonorrhoeae detection by immobilizing 5'-amino-labeled Neisseria gonorrhoeae probe (aDNA) using glutaraldehyde as a cross-linker. PANI-CNT/ITO and aDNA-Glu-PANI-CNT/ITO electrodes have been characterized using scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). This bioelectrode can be used to detect N. gonorrhoeae using methylene blue (MB) as redox indicator with response time of 60 s and stability of about 75 days when stored under refrigerated conditions. DPV studies reveal that this bioelectrode can detect complementary DNA concentration from 1 x 10(-6) M to 1 x 10(-17) M with detection limit of 1.2 x 10(-17) M. Further, this bioelectrode (aDNA-Glu-PANI-CNT/ITO) exhibits specificity toward N. gonorrhoeae species and shows negative response with non-Neisseria gonorrhoeae Neisseria species (NgNS) and other gram negative bacteria (GNB).
A sequence-specific electrochemical sexually transmitted disease (STD) sensor based on self-assem... more A sequence-specific electrochemical sexually transmitted disease (STD) sensor based on self-assembled monolayer of thiolated DNA probe specific to target opa gene for detection of Gonorrhoea, a sexually transmitted disease has been fabricated. 6-Mercapto-1-hexanol (MCH) has been used as a blocking agent to facilitate oligos "stand" up at the surface, a configuration favoring subsequent DNA hybridization and to repel non-specific adsorption of undesired DNA. The results of differential pulse voltammetric studies of this STD sensor reveal low detection limit (1.0 × 10(-18)M) and a wide dynamic range (from 1.0 × 10(-6)M to 0.5 × 10(-18)M) arising due to the stable hybridization using methylene blue as an electro-active DNA hybridization indicator. The experimental results with genomic DNA, clinical patient sample of Neisseria gonorrhoeae, culture of non-N. gonorrhoeae Neisseria species (NgNS) and gram negative bacteria indicate that the fabricated sensor is specific to this STD.
Indian Journal of Sexually Transmitted Diseases and AIDS, 2009
... Diagnostic approach to gonorrhoea: Limitations Rachna Verma 1 , Seema Sood 1 , Manjubala 2 , ... more ... Diagnostic approach to gonorrhoea: Limitations Rachna Verma 1 , Seema Sood 1 , Manjubala 2 , Arti Kapil 1 , VK Sharma 3 1 Department of Microbiology, AIIMS, India 2 Regional STD Teaching, Training and Research Center, VMMC & SJH, India 3 Department of Dermatology ...
Electrochemically fabricated nano-composite film of chitosan (CH)-iron oxide (Fe 3 O 4) has been ... more Electrochemically fabricated nano-composite film of chitosan (CH)-iron oxide (Fe 3 O 4) has been used to detect gonorrhoea, a sexually transmitted disease (STD) via immobilization of biotinylated probe DNA (BDNA) using avidin-biotin coupling for rapid and specific (mismatch-discriminating) DNA hybridization. The presence of Fe 3 O 4 nanoparticles (∼18 nm) increases the electro-active surface area of the nanobiocomposite that provides desirable environment for loading of DNA with better conformation leading to increased electron transfer kinetics between the medium and electrode. The differential pulse voltammetric (DPV) studies have been conducted using BDNA/avidin/CH-Fe 3 O 4 /ITO electrode owing to the reduction of the methylene blue (MB) indicator and investigate electron transfer between MB moieties and electrode for one and two-bases mismatch. This STD biosensor is found to have a detection limit (1 × 10 −15 M) and a wide dynamic range (from 1 × 10 −16 M to 1 × 10 −6 M) using the complementary target DNA. In addition, the sensing system can be utilized to accurately discriminate complementary sequence from mismatch sequences.
STD (sexually transmitted disease, Gonorrhoea) sensor based on nucleic acid probe (from Opa, a mu... more STD (sexually transmitted disease, Gonorrhoea) sensor based on nucleic acid probe (from Opa, a multi-copy gene of Neisseria gonorrhoeae) functionalized nanostructured-polyaniline coated onto indium-tin-oxide-coated glass plate has been fabricated using avidin-biotin as cross-linking agent. This DNA functionalized electrode can specifically detect upto 0.5 × 10 −15 M of complementary target within 60 s of hybridization time at 25 • C by differential pulse voltammetry (DPV) using methylene blue as electro-active DNA hybridization indicator. This highly sensitive and specific nucleic acid functionalized nanostructured-polyaniline electrode can distinguish presence of N. gonorrhoeae from Neisseria meningitidis and Escherichia coli culture and spiked samples from the urethral swabs of the patients.
The nanocomposite based on polyaniline (PANI)-iron oxide nanoparticles (nFe 3 O 4) and multi wall... more The nanocomposite based on polyaniline (PANI)-iron oxide nanoparticles (nFe 3 O 4) and multi walled carbonnanotubes (CNT) has been fabricated onto indium tin oxide (ITO) coated glass plate via facile electrochemical synthesis of polyaniline in presence of nFe 3 O 4 (~20 nm) and CNT (20-80 nm in diameter). The results of transmission electron microscopic studies show evidence of coating of PANI and nFe 3 O 4 onto the CNT. The PANI-nFe 3 O 4-CNT/ITO nanoelectrode has been characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy studies. The biotinylated nucleic acid probe sequence consisting of 20 bases has been immobilized onto PANI-nFe 3 O 4-CNT/ITO nanoelectrode using biotin-avidin coupling. It is shown that the PANI-nFe 3 O 4-CNT platform based biosensor can be used to specifically detect bacteria (N. gonorrhoeae) at minute concentration as low as (1× 10 − 19 M) indicating high sensitivity within 45 s of hybridization time at 298 K by differential pulse voltammetry using methylene blue as electroactive indicator. This bacterial sensor has also been tested with 4 positive and 4 negative PCR amplicons of gonorrhoea affected patient samples. The results of these studies have implications towards the fabrication of a handheld device for Neisseria gonorrhoeae detection that may perhaps result in a decrease in the human immunodeficiency virus infections.
ABSTRACT The present invention relates to nucleic acid primers and probe for detection of Neisser... more ABSTRACT The present invention relates to nucleic acid primers and probe for detection of Neisseria gonorrhoeae. The use of the probe sequence for detection of N. gonorrhoeae in clinical samples (endocervical swabs in females and urethral discharge in males) has been described along with the different biomaterials to which it can be immobilized for detection purpose by the biosensor technology. In addition to its use as a detection probe, the sequence can be used as primer for in vitro amplification of N. gonorrhoeae in clinical samples. The discriminatory capacity of the unique sequence has been established by utilizing the panel of non-N. gonorrhoeae Neisseria species (NgNS) as well as other gram-negative bacteria.
Indian journal of dermatology, venereology and leprology
The pathogenesis is unknown though Torrelo et al. suggested that vaccines may induce an immune re... more The pathogenesis is unknown though Torrelo et al. suggested that vaccines may induce an immune response against specific and non-specific antigens in patients with trigger factors and that the trauma of injection may cause endothelial damage and tissue hypoxia. [1] Different treatments have been tried including potent topical corticosteroids, systemic corticosteroids and methotrexate but none has proved effective. [1] Even though no case of progression to generalized morphea or of the development of systemic symptoms has been reported, we consider it important to follow-up the patient in order to assess the symmetric growth of the limbs and detect any appearance of systemic symptoms. [4]
ABSTRACT Introduction The diagnosis of child abuse is based on a combination of child’s history, ... more ABSTRACT Introduction The diagnosis of child abuse is based on a combination of child’s history, physical findings, and when appropriate, laboratory and other tests. Overall, the diagnosis is often complicated but suspicion should always be followed by further investigations. Formulating a conclusion and reaching a diagnosis of child abuse may require the assistance and coming together of different specialities in the hospital. Case history: A seven year old girl presented to the Dermatology and Venereology OPD of a tertiary hospital in New Delhi, India with chief complaints of vaginal discharge for last 4 years. The vaginal swab(s) on Gram stain revealed numerous pus cells with GNDC, intracellular as well as extracellular. The child was treated based on clinical suspicion of gonorrhoea. However, RCUT put up from suspected colonies on modified Thayer Martin medium was positive for Neisseria meningitidis. In addition, crgA gene PCR from DNA extracted from the swab as well as the isolate was positive for N. meningitidis while opa-gene PCR for N. gonorrhoeae was negative. Although she was initially treated for suspected gonococcal infection, the clinical diagnosis was refuted by the results of culture and PCR. Discussion & conclusion: The findings of the present case emphasise the importance of careful culture techniques for isolation of organisms & their correct identification which is the cornerstone of appropriate therapy. It also drives home the necessity of using lactose in Rapid Carbohydrate Utilization Test (RCUT), which is crucial to differentiate between N. meningitidis and N. lactamica. It is also important for the laboratory (especially one that is considered a referral laboratory) to have capacity to perform molecular tests to confirm or refute presumptive findings, as was done in the present case. This observation stresses that an interdisciplinary approach appears to be a valuable tool for evaluating such children.
In the absence of a single nucleic acid amplification test (NAAT) that is both highly specific an... more In the absence of a single nucleic acid amplification test (NAAT) that is both highly specific and sensitive for gonorrhoea, many have put forward the 16S-based assay as a confirmatory test for Neisseria gonorrhoeae. This study was undertaken to evaluate the performance of PCR based on 16S ribosomal gene in comparison with a porA pseudogene-based assay. The specificity of both the porA pseudogene-based PCR and 16S ribosomal gene PCR was checked against a panel of strains comprising of non N gonorrhoeae Neisseria sp (NgNS) and other gram-negative and gram-positive bacteria. The sensitivity studies were performed using different dilutions of N gonorrhoeae DNA. PCRs were also done on endocervical and urethral swab samples collected from a total of 100 female and 50 male patients presenting to sexually transmitted disease clinics, Dermatology OPD of AIIMS and Safdarjang Hospital, New Delhi, India, recruited as per inclusion criteria. PCR assay based on 16S ribosomal gene showed cross-reactivity with three of six strains of N sicca. The porA pseudogene-based PCR was highly specific. Analytical sensitivity of 16S-based ribosomal assay was more than that of porA pseudogene-based assay. In clinical samples, for female patients, sensitivity, specificity, positive predictive value and negative predictive value of 16S ribosomal assay was 100% (95% CI 51.7% to 100%), 91.5% (95% CI 83.4% to 96%), 42.9% (95% CI 18.8% to 70.4%) and 100% (95% CI 94.7% to 100%), respectively, while for the male patients it was 100% (95% CI 85% to 100%), 95.5% (95% CI 75.1% to 99.8%), 96.6% (95% CI 80.4% to 99.8%) and 100% (95% CI 80.8% to 100%), respectively. The data presented in this report supports use of 16S ribosomal assay as a screening assay only. The porA pseudogene target is highly specific for N gonorrhoeae and may be used as a supplemental assay.
Polyaniline/carbon nanotubes composite (PANI-CNT) electrochemically deposited onto indium-tin-oxi... more Polyaniline/carbon nanotubes composite (PANI-CNT) electrochemically deposited onto indium-tin-oxide (ITO) coated glass plate has been utilized for Neisseria gonorrhoeae detection by immobilizing 5(-amino-labeled Neisseria gonorrhoeae probe (aDNA) using glutaraldehyde as a cross-linker. PANI-CNT/ITO and aDNA-Glu-PANI-CNT/ITO electrodes have been characterized using scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). This bioelectrode can be used to detect N. gonorrhoeae using methylene blue (MB) as redox indicator with response time of 60 s and stability of about 75 days when stored under refrigerated conditions. DPV studies reveal that this bioelectrode can detect complementary DNA concentration from 1 T 10 S6 M to 1 T 10 S17 M with detection limit of 1.2 T 10 S17 M. Further, this bioelectrode (aDNA-Glu-PANI-CNT/ITO) exhibits specificity toward N. gonorrhoeae species and shows negative response with non-Neisseria gonorrhoeae Neisseria species (NgNS) and other gram negative bacteria (GNB).
A sequence-specific electrochemical sexually transmitted disease (STD) sensor based on self-assem... more A sequence-specific electrochemical sexually transmitted disease (STD) sensor based on self-assembled monolayer of thiolated DNA probe specific to target opa gene for detection of Gonorrhoea, a sexually transmitted disease has been fabricated. 6-Mercapto-1-hexanol (MCH) has been used as a blocking agent to facilitate oligos "stand" up at the surface, a configuration favoring subsequent DNA hybridization and to repel non-specific adsorption of undesired DNA. The results of differential pulse voltammetric studies of this STD sensor reveal low detection limit (1.0 × 10 −18 M) and a wide dynamic range (from 1.0 × 10 −6 M to 0.5 × 10 −18 M) arising due to the stable hybridization using methylene blue as an electro-active DNA hybridization indicator. The experimental results with genomic DNA, clinical patient sample of Neisseria gonorrhoeae, culture of non-N. gonorrhoeae Neisseria species (NgNS) and gram negative bacteria indicate that the fabricated sensor is specific to this STD.
Indian Journal of Sexually Transmitted Diseases and AIDS, 2009
... Diagnostic approach to gonorrhoea: Limitations Rachna Verma 1 , Seema Sood 1 , Manjubala 2 , ... more ... Diagnostic approach to gonorrhoea: Limitations Rachna Verma 1 , Seema Sood 1 , Manjubala 2 , Arti Kapil 1 , VK Sharma 3 1 Department of Microbiology, AIIMS, India 2 Regional STD Teaching, Training and Research Center, VMMC & SJH, India 3 Department of Dermatology ...
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