Clinical and microbiological characteristics of bloodstream infection caused by Klebsiella pneumoniae harboring rmpA in Japanese adults.

We investigated the clinical features of bloodstream infections (BSIs) caused by Klebsiella pneumoniae harboring rmpA and molecular characteristics of the bacteria. We retrospectively investigated adult patients with K. pneumoniae BSI from January 2010 to March 2021 at Nagasaki University Hospital. A matched case-control study in a 1:3 ratio was conducted to clarify the clinical and bacterial characteristics of BSI caused by rmpA-positive K. pneumoniae compared with those caused by rmpA-negative isolates. Antimicrobial susceptibility testing and multilocus sequence typing (MLST) were performed for rmpA-positive isolates. The rmpA was detected in 36 (13.4%) of the 268 isolates. Of these 36 isolates, 31 (86.1%) harbored iucA and 35 (97.2%) each possessed peg-344 and iroB; capsular types were identified as K1 in 9 (25.0%) and K2 in 10 isolates (27.8%). Contrarily, of the 108 rmpA-negative isolates, which were matched for case-control studies, 5 isolates (4.6%) harbored iucA and 1 (0.9%) each possessed peg-344 and iroB; 2 (1.9%) and 3 isolates (2.8%) had K1 and K2 capsular types, respectively. Among the rmpA-positive isolates, ST23/K1 (eight isolates) was the most frequent, followed by ST412/non-K1/K2 (seven isolates), ST86/K2 (five isolates), and ST268/non-K1/K2 (four isolates). In a multivariate analysis using clinical factors, liver abscess positively correlated with rmpA-positive isolates, whereas biliary tract infection and use of anticancer drugs negatively correlated with rmpA-positive isolates in patients with K. pneumoniae BSI. Considering the correlation between rmpA-positive isolates and clinical features, rmpA can be used as a marker for understanding the pathophysiology of K. pneumoniae BSI.

Association between serum vitamin D levels and Helicobacter pylori cytotoxic-associated gene A seropositivity: a cross-sectional study in US adults from NHANES III.

OBJECTIVE: To assess the association of serum vitamin D (VD) levels and Helicobacter pylori (H. pylori) cytotoxic-associated gene A (CagA) seropositivity, and further explore potential effect modifiers in this association. DESIGN: Cross-sectional study. SETTING: Data from phase I of the National Health and Nutrition Examination Survey (NHANES III, 1988-1991) led by the Center for Disease Control and Prevention. PARTICIPANTS: A total of 3512 US adults (≥20 years) with both serum VD levels and H. pylori CagA antibody data from NHANES III were included in the analysis. METHODS: VD deficiency was defined as serum 25(OH)D concentrations<20 ng/mL. Logistic regression models were used to assess the association of serum VD levels and H. pylori CagA seropositivity (VD-Hp CagA+), and stratification analyses were used to explore potential effect modifiers. RESULTS: There was no significant association of VD-Hp CagA+ in the general population. But serum 25(OH)D concentrations were associated with H. pylori CagA+ in non-Hispanic whites (adjusted OR=1.02, 95% CI: 1.00 to 1.03), other races/ethnicities (adjusted OR=1.08, 95% CI: 1.01 to 1.06), populations born in other countries (adjusted OR=1.09, 95% CI: 1.04 to 1.15) or occasional drinkers (adjusted OR=0.93, 95% CI: 0.88 to 0.99). VD deficiency was associated with H. pylori CagA+ in non-Hispanic whites (adjusted OR=0.69, 95% CI: 0.53 to 0.92), populations born in other countries (adjusted OR=0.47, 95% CI: 0.25 to 0.89), non-drinkers (adjusted OR=0.80, 95% CI: 0.65 to 0.99), occasional drinkers (adjusted OR=2.53, 95% CI: 1.06 to 6.05), population with first quartile level of serum ferritin (adjusted OR=0.70, 95% CI: 0.51 to 0.96) or fourth quartile level of serum folate (adjusted OR=0.63, 95% CI: 0.46 to 0.87). CONCLUSIONS: Racial/ethnic differences and different serum ferritin or serum folate levels may be effect modifiers for the association of VD-Hp CagA+.

An electrochemical aptasensor for Mycobacterium tuberculosis ESAT-6 antigen detection using bimetallic organic framework.

A label-free electrochemical aptasensor is reported for sensitive detection of the 6-kDa early secreted antigenic target (ESAT-6). For the first time, the bimetallic organic framework (b-MOF) of Zr-MOF-on-Ce-MOF was decorated with nitrogen-doped graphene (NG) and applied as the matrix for electroactive toluidine blue (Tb) to form the NG@Zr-MOF-on-Ce-MOF@Tb nanohybrid. The prepared nanohybrid with excellent hydrophilicity, dispersibility, and large specific surface exhibited significant electrochemical response. This nanohybrid could be directly used for anchoring ESAT-6 binding aptamers (EBA) through the interaction between the 5'-phosphate group (PO43-) of EBA and Zr4+ of Zr-MOF. The signal response before and after incubating the ESAT-6 antigen has been evaluated by cyclic voltammetry at a scan rate of 100 mV s-1 from - 0.7 to 0.3 V (vs. SCE). Under optimal conditions, the proposed aptasensor displayed a wide linear range from 100 fg mL-1 to 10 ng mL-1 with a limit of detection (LOD) of 12 fg mL-1. The developed method showed good reproducibility with a relative standard deviation (RSD) of 2.27%. The aptasensor showed favorable results in the analysis of the real samples. With these merits, the aptasensor has exceptional potential as a diagnostic tool for tuberculosis in clinical practice.

Microarray-based selection of a serum biomarker panel that can discriminate between latent and active pulmonary TB.

Bacterial culture of M. tuberculosis (MTB), the causative agent of tuberculosis (TB), from clinical specimens is the gold standard for laboratory diagnosis of TB, but is slow and culture-negative TB cases are common. Alternative immune-based and molecular approaches have been developed, but cannot discriminate between active TB (ATB) and latent TB (LTBI). Here, to identify biomarkers that can discriminate between ATB and LTBI/healthy individuals (HC), we profiled 116 serum samples (HC, LTBI and ATB) using a protein microarray containing 257 MTB secreted proteins, identifying 23 antibodies against MTB antigens that were present at significantly higher levels in patients with ATB than in those with LTBI and HC (Fold change > 1.2; p < 0.05). A 4-protein biomarker panel (Rv0934, Rv3881c, Rv1860 and Rv1827), optimized using SAM and ROC analysis, had a sensitivity of 67.3% and specificity of 91.2% for distinguishing ATB from LTBI, and 71.2% sensitivity and 96.3% specificity for distinguishing ATB from HC. Validation of the four candidate biomarkers in ELISA assays using 440 serum samples gave consistent results. The promising sensitivity and specificity of this biomarker panel suggest it merits further investigation for its potential as a diagnostic for discriminating between latent and active TB.

A primary Chlamydia trachomatis genital infection of rhesus macaques identifies new immunodominant B-cell antigens.

To identify immunodominant antigens that elicit a humoral immune response following a primary and a secondary genital infection, rhesus monkeys were inoculated cervically with Chlamydia trachomatis serovar D. Serum samples were collected and probed with a protein microarray expressing 864/894 (96.4%) of the open reading frames of the C. trachomatis serovar D genome. The antibody response to the primary infection was analyzed in 72 serum samples from 12 inoculated monkeys. The following criteria were utilized to identify immunodominant antigens: proteins found to be recognized by at least 75% (9/12) of the infected monkeys with at least 15% elevations in signal intensity from week 0 to week 8 post infection. All infected monkeys developed Chlamydia specific serum antibodies. Eight proteins satisfied the selection criteria for immunodominant antigens: CT242 (OmpH-like protein), CT541 (mip), CT681 (ompA), CT381 (artJ), CT443 (omcB), CT119 (incA), CT486 (fliY), and CT110 (groEL). Of these, three antigens, CT119, CT486 and CT381, were not previously identified as immunodominant antigens using non-human primate sera. Following the secondary infection, the antibody responses to the eight immunodominant antigens were analyzed and found to be quite different in intensity and duration to the primary infection. In conclusion, these eight immunodominant antigens can now be tested for their ability to identify individuals with a primary C. trachomatis genital infection and to design vaccine strategies to protect against a primary infection with this pathogen.

Evaluation of the CARDS toxin and its fragment for the serodiagnosis of Mycoplasma pneumoniae infections.

Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen in community-acquired pneumonia. The community-acquired respiratory distress syndrome (CARDS) toxin is the only known virulence factor of M. pneumoniae. It is worth exploring whether this toxin can be used as a candidate antigen for the serodiagnosis of M. pneumoniae. In this study, the full-length, N-terminal, and C-terminal regions of the CARDS toxin were expressed and purified, and serological reactions were evaluated using ELISA. A total of 184 serum samples were collected and tested using a commercialized test kit. Eighty-seven samples were positive, and 97 samples were negative for infection. The purified recombinant proteins were used as antigens to test the serum via indirect ELISA. The sensitivity of the CARDS toxin, the N-terminal region, and the C-terminal region were 90.8%, 90.8%, and 92.0%, respectively. The specificity of the CARDS toxin, the N-terminal region, and the C-terminal region were 85.6%, 73.2%, and 93.8%, respectively. All three CARDS toxin proteins exhibited good reactivity, of which the C-terminal region had a good discrimination ability in human sera. This may have a potential diagnostic value for M. pneumoniae infections.

Point-of-care detection of tuberculosis using magnetoresistive biosensing chip.

In this paper, a highly sensitive and specific technique based on the principle of giant magnetoresistance (GMR) has been proposed for the early stage Tuberculosis (TB) diagnostics. This GMR biosensing assay employs monoclonal antibodies against M. tuberculosis specific ESAT-6 antigen with the use of magnetic nanoparticles (MNPs) as labels. MNPs bind to the GMR sensor in presence of ESAT-6 and the binding is proportional to the ESAT-6 protein concentration leading to the change in overall resistance of GMR sensor. GMR biosensor simulation showed that ESAT-6 concentration can be detected in the range of pg/mL in comparison to the other transduction techniques available for ESAT-6 detection and further, the signal strength increased with the increase in the concentration. This work has shown that the GMR biosensing strategy is pertinent for the TB detection at the primitive phases when compared with other magnetic techniques used for TB diagnostics.

Simultaneous testing of immunological sensitization to multiple antigens in sarcoidosis reveals an association with inorganic antigens specifically related to a fibrotic phenotype.

Organic and inorganic antigens were studied simultaneously in the same cohort of sarcoidosis patients to investigate whether correlations between clinical characteristics and immunological sensitization could reveal new phenotypes. Sensitization to antigens of mycobacteria, Propionibacterium acnes catalase and vimentin was investigated in 201 sarcoidosis and 51 obstructive sleep apnoea patients, serving as control group. Sensitization to aluminium, beryllium, silica and zirconium was also studied in 105 of the sarcoidosis patients and in 24 of the controls. A significantly higher percentage of sarcoidosis patients (27·6%) than controls (4·2%) had an immunological response to metals or silica (P = 0·014). A higher percentage of these sarcoidosis patients showed fibrosis on chest X-ray 5 years after the diagnosis (69·2 versus 30·3%, P = 0·016). No significant differences in mycobacterial or vimentin enzyme-linked immunospot (ELISPOT) assay results were observed between sarcoidosis and control patients. A significantly lower percentage of sarcoidosis patients (3·5%) than control patients (15·7%) had a positive ELISPOT for P. acnes catalase (P = 0·003). However, sarcoidosis patients sensitized to P. acnes catalase were more likely to have skin involvement, while sarcoidosis patients sensitized to mycobacterial antigens were more likely to have cardiac involvement. Our study suggests a more prominent role for inorganic triggers in sarcoidosis pathogenesis than previously thought. Immunological sensitization to inorganic antigens was associated with development of fibrotic sarcoidosis. No association was found between sensitization to bacterial antigens or vimentin and sarcoidosis in Dutch patients. However, our data suggest that trigger-related phenotypes can exist in the heterogeneous population of sarcoidosis patients.

Absence of Toxemia in Clostridioides difficile Infection: Results from Ultrasensitive Toxin Assay of Serum.

Clostridioides difficile infection (CDI) is caused by Toxins A and B, secreted from pathogenic strains of C. difficle. This infection can vary greatly in symptom severity and in clinical presentation. Current assays used to diagnose CDI may lack the required sensitivity to detect the exotoxins circulating in blood. The ultrasensitive single molecule array (Simoa) assay was modified to separately detect toxin A and toxin B in serum with a limit of detection at the low picogram level. When applied to a diverse cohort, Simoa was unable to detect toxins A or B in serum from patients with CDI, including many classified as having severe disease. The detection of toxin may be limited by the inference of antitoxin antibodies circulating in serum. This result does not support the hypothesis that toxemia occurs in C. difficile infection, conflicting with the findings of other published reports.

Development of an in-house capture ELISA: An attempt to detect CagA antigen in sera of Helicobacter pylori infected patients.

The CagA protein one of the key virulence factors of Helicobacter pylori plays an important role in the pathogenesis of peptic ulcer diseases. Unfortunately the cagA gene status can only be determined by PCR while serology is an alternative approach to detect antigens or antibodies. Our aim is to detect the CagA antigen in sera of infected subjects by the development of an in-house capture ELISA test. Gastric antral biopsies and serum samples were collected from 63 patients. PCR was used to determine the cagA status. Our previously developed recombinant CagA protein and monoclonal antibody were used for setting up the capture ELISA test. H. pylori positive [(38 gastritis, 14 duodenal ulcers (DU), 11 gastric ulcer (GU)] patients were determined by PCR. The cagA gene was detected in 21 (55%) of gastritis, 11 (78%) of DU and 7 (60%) of GU patients. The reagents used in setting up the capture ELISA test following optimization displayed high performance. This study showed that our developed in-house capture ELISA has the potential to detect the CagA antigen at very low concentrations even though not detected in our H. pylori infected patients sera but we are also intended to use it in saliva and stool samples.

Diversity of SCCmec elements and spa types in South African Staphylococcus aureus mecA-positive blood culture isolates.

BACKGROUND: The prevalence of Staphylococcus aureus varies depending on the healthcare facility, region and country. To understand its genetic diversity, transmission, dissemination, epidemiology and evolution in a particular geographical location, it is important to understand the similarities and variations in the population being studied. This can be achieved by using various molecular characterisation techniques. This study aimed to provide detailed molecular characterisation of South African mecA-positive S. aureus blood culture isolates by describing the SCCmec types, spa types and to lesser extent, the sequence types obtained from two consecutive national surveillance studies. METHODS: S. aureus blood culture isolates from a national laboratory-based and enhanced surveillance programme were identified and antimicrobial susceptibility testing was performed using automated systems. A real-time PCR assay confirmed the presence of the methicillin-resistance determinant, mecA. Conventional PCR assays were used to identify the SCCmec type and spa type, which was subsequently analysed using the Ridom StaphType™ software. Multilocus sequence typing was performed on selected isolates using conventional methods. MRSA clones were defined by their sequence type (ST), SCCmec type and spa type. RESULTS: A detailed description of findings is reported in this manuscript. SCCmec type III predominated overall followed by type IV. A total of 71 different spa types and 24 novel spa types were observed. Spa type t037 was the most common and predominated throughout followed by t1257. Isolates were multidrug resistant; isolates belonging to all SCCmec types were resistant to most of the antibiotics with the exception of type I; isolates with spa type t045 showed resistance to all antibiotics except vancomycin. The most diverse SCCmec-spa type complex was composed of the SCCmec type IV element and 53 different spa types. CONCLUSION: Although ST data was limited, thereby limiting the number of clones that could be identified, the circulating clones were relatively diverse.

Real-Time and Label-Free Monitoring of Biomolecular Interactions within Complex Biological Media Using a Silica Colloidal Crystal Film.

A method capable of real-time and label-free monitoring of biomolecular interactions within whole blood, without any sample separation and label process, is described. This was accomplished using silica colloidal crystal (SCC) films, three-dimensionally ordered silica particle arrays whose interference effect is a function of their optical thickness, as interference-sensitive substrates. Interactions between immunoglobulin G (IgG) and protein A from Staphylococcus aureus (SPA) conjugates with changes in the optical thickness of SCC films were monitored spectroscopically. Successful detection of IgG was achieved in the buffer and whole blood. This system constitutes a simple label-free analysis showing great potential in monitoring interactions between biomolecules in complex biological media.

Seropositivity for Helicobacter pylori and hepatobiliary cancers in the PLCO study.

Helicobacter has been suggested to play a possible role in hepatitis, gallstones, and hepatobiliary tumours. We assessed whether seropositivity to 15 H. pylori proteins was associated with subsequent incidence of 74 biliary tract and 105 liver cancer cases vs. 357 matched controls in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO). Odds ratios and 95% confidence intervals were computed by conditional logistic regression after adjustment for known hepatobiliary cancer risk factors. H. pylori seropositivity was not associated with either biliary tract (1.76, 0.90-3.46) or liver cancer (0.87, 0.46-1.65). CagA seropositivity was associated with both endpoints, although the latter association was not statistically significant (biliary tract: 2.16, 1.03-4.50; liver cancer: 1.96, 0.98-3.93) and neither association was statistically significant after correcting for multiple comparisons. Together, these results suggest possible associations between H. pylori and hepatobiliary cancer and suggest the value of future studies investigating the association.Trial registration number: NCT00339495.

Helicobacter pylori seroprevalence in six different ethnic groups living in Amsterdam: The HELIUS study.

BACKGROUND: Helicobacter pylori prevalence varies greatly worldwide. We explored the prevalence of H. pylori and CagA seropositivity among adults aged 18-44 years living in the Netherlands by ethnicity and migration status (first vs second generation). MATERIALS AND METHODS: Participants from six different ethnic groups were selected from the population-based multi-ethnic HELIUS study in Amsterdam, the Netherlands. Serum samples were tested for H. pylori antigens using a validated Luminex-based multiplex serology assay. Prevalence ratios were estimated using Poisson regression analysis. RESULTS: A total of 4683 participants aged 18-44 years were randomly selected based on sex, ethnicity, and age. H. pylori seroprevalence was highest in the Ghanaian group (84%), followed by Moroccan (81%), Turkish (66%), African Surinamese (51%), South-Asian Surinamese (48%), and Dutch (17%) participants. All ethnic minority groups had a significantly higher risk of being H. pylori seropositive compared to the Dutch group. This association was strongest among participants born outside the Netherlands (first generation), but was still significant and apparent among second-generation participants. Among first-generation participants, all groups, except the Moroccans, had a significantly higher proportion of individuals with a cagA + H. pylori strain compared to the Dutch participants. CONCLUSION: Helicobacter pylori seroprevalence among first-generation migrants is high in the Netherlands and remains elevated among second-generation migrants (ie, those born in the Netherlands). High exposure to H. pylori, and especially to the more virulent cagA+ strain, highlights the need for tailored prevention of gastric diseases (notably peptic ulcers and cancers) among migrants.

The Relation of Cytotoxin-Associated Gene-A Seropositivity with Vitamin B12 Deficiency in Helicobacter pylori-Positive Patients.

BACKGROUND AND AIM: As a worldwide infectious bacterium, H. pylori leads to stomach pathologies such as gastritis, peptic ulcer, gastric cancer, MALToma, and various extragastric manifestations. In our study, we aimed to investigate the association between serum vitamin B12 level and cytotoxin-associated gene-A (CagA) seropositivity, which is one of the virulence factors of Helicobacter pylori (H. pylori). METHOD: This study has been conducted on 289 patients who have met the inclusion criteria. Within these patients, 213 of them were H. pylori positive and 76 were negative. Vitamin B12 and CagA-IgG levels were assessed in consecutive dyspeptic patients undergoing upper endoscopy. RESULTS: Out of 289 patients, 51.9% were women (n = 150) and H. pylori was detected in 213 (73.7%) patients. Histopathological evaluation with modified Sydney classification revealed lymphocyte infiltration in 66.8% (n = 193), activation in 46% (n = 133), metaplasia in 11.4% (n = 33), atrophy in 11.4% (n = 33), and lymphoid follicles in 21.1% (n = 61) of the patients. Within H. pylori-positive patients, the ratio of CagA positivity was 57.3% (n = 122). Low B12 vitamin level was significantly correlated with existence of H. pylori (p=0.02), CagA (p=0.002), lymphocyte (p=0.006), metaplasia (p=0.001), atrophy (p=0.001), and lymphoid follicles (p=0.006). Positivity of CagA has been detected to be statistically corelated with lymphocyte (p=0.001) and activation (p=0.005); however, the same relation was not present with atrophy (p=0.236). CONCLUSION: In conclusion, B12 deficiency was positively correlated with CagA positivity and gastric inflammatory activity.

Emergence of Klebsiella pneumoniae ST11 co-producing NDM-1 and OXA-48 carbapenemases in Greece.

OBJECTIVES: Klebsiella pneumoniae is a well-known pathogen frequently implicated in serious life-threatening nosocomial infections. Here we present a K. pneumoniae isolate (AHEPA1046) co-harbouring blaNDM-1 and blaOXA-48 isolated from a blood sample of an inpatient in Thessaloniki, Greece. METHODS: Whole-genome sequencing (WGS) was performed using an Illumina MiniSeq Sequencing System. Multilocus sequence typing (MLST) was performed using a BLAST-based approach, and antimicrobial resistance genes and plasmid replicons were identified by ResFinder and PlasmidFinder, respectively. The Rapid Annotation using Subsystem Technology (RAST) v.2.0 server was used for genome annotation. RESULTS: WGS analysis revealed the complete resistome of K. pneumoniae AHEPA1046. The strain harboured blaNDM-1 and blaOXA-48 together with 16 additional antimicrobial resistance genes and was resistant to carbapenems, aminoglycosides, quinolones, macrolides, tetracyclines, trimethoprim, fosfomycin and phenicols. Moreover, it was classified as ST11. CONCLUSION: This is the first report of a K. pneumoniae clinical isolate from Greece co-producing NDM-1 and OXA-48 carbapenemases and is one of a few reported worldwide.

Rapid detection of the main carbapenemases in Brazil directly from spiked blood culture using the RESIST-3 O.K.N. immunoassay.

The emergence of carbapenem-resistant Enterobacterales (CRE) is a matter of public health concern. Carbapenemases are the main mechanism of resistance among CRE, and its rapid detection is essential. The detection of carbapenemases usually requires culture-based methods and molecular assays, which may be costly and need long turnaround times. Recently, an easy and rapid immunochromatographic assay for carbapenemases (OXA-48, KPC, and NDM) detection based in lateral flow immunoassay with specific monoclonal antibodies on a nitrocellulose membrane has been developed. We aimed to evaluate the RESIST-3 O.K.N. in colonies from pure culture as well as in spiked blood cultures with Enterobacterales. All carbapenemase producers (CP) presenting the OXA-48-like, KPC, and NDM enzymes presented positive results in both pure colonies and spiked blood cultures. None of the carbapenemase non-producers (CNP) presented positive results in the tests. A total of 97% CP isolates presented positive results in pure colonies in less than 5 min. For CP directly from blood culture, the mean time to positivity for OXA-48-like and KPC was 1 min, whereas it was 25 min for NDM. Our results indicate that this immunoassay can be used to detect carbapenemases directly from blood culture bottles in a routine diagnostic laboratory, which would reduce the turnaround time of CP detection.

A sandwich-type electrochemical aptasensor for Mycobacterium tuberculosis MPT64 antigen detection using C60NPs decorated N-CNTs/GO nanocomposite coupled with conductive PEI-functionalized metal-organic framework.

The present work described a novel sandwich-type electrochemical aptasensor for rapid and sensitive determination of Mycobacterium tuberculosis MPT64 antigen. Herein, a novel carbon nanocomposite composed of fullerene nanoparticles, nitrogen-doped carbon nanotubes and graphene oxide (C60NPs-N-CNTs/GO) was facilely synthesized for the first time, which not only possessed a large specific surface area and excellent conductivity, but also exhibited outstanding inherent electroactive property, and therefore served as nanocarrier and redox nanoprobe simultaneously. Gold nanoparticles (AuNPs) was then uniformly anchored onto the surface of such nanocomposite via Au-N bonds to bind with MPT64 antigen aptamer Ⅱ (MAA Ⅱ), forming the tracer label to realize generation and amplification of electrochemical signal. Additionally, conductive polyethyleneimine (PEI)-functionalized Fe-based metal-organic framework (P-MOF) was used as a sensing platform to absorb bimetallic core-shell Au-Pt nanoparticles (Au@Pt), which could accelerate electron transfer and increase the immobilization of MPT64 antigen aptamer Ⅰ (MAA Ⅰ). After the typical sandwich-type protein-aptamer recognition, the inherent electroactivity of the tracer label was provoked by tetraoctylammonium bromide (TOAB), leading to a well-defined current response. Under the optimum condition, the proposed aptasensor showed a wide linear range for MPT64 detection from 1 fg/mL to 1 ng/mL with a limit of detection (LOD) as low as 0.33 fg/mL. More importantly, it was successfully used for MPT64 antigen detection in human serum, exhibiting a promising prospect for TB diagnosis in clinical practice.

Relationship between Helicobacter pylori cytotoxin-associated gene A protein with clinical outcomes in patients with rheumatoid arthritis.

INTRODUCTION: The Helicobacter pylori(H. pylori) infection leads to intensification of symptoms and calenture of autoimmune diseases. This study aimed to evaluate the relationship between H. pylori infection and clinical outcomes in rheumatoid arthritis (RA) patients. METHODOLOGY: This study was performed on 100 RA patients. Blood samples were collected for measuring Anti-H. pylori IgG antibodies and cytotoxin-associated gene A (CagA) protein. Fresh fecal samples were also collected and the fecal H. pylori antigen was extracted. Clinical condition as well as severity and type of RA symptoms in both groups of H. pylori positive and H. pylori negative were also compared. RESULTS: Serum levels of rheumatoid factor (RF), ESR, CRP, anti-cyclic citrullinated peptide (Anti-CCP), and anti-mutated citrullinated vimentin (Anti-MCV) were significantly higher in H. pylori positive patients than in H. pylori negative patients (P < 0.05). Serum RF, ESR, CRP and Anti-MCV levels were significantly higher in CagA positive patients than in CagA negative patients (P < 0.05). There were no significant differences in DAS-28 scores between H. pylori positive and H. pylori negative patients (P = 0.064) as well as between patients with positive and negative fecal H. pylori antigen (P = 0.237). However, DAS-28 score was significantly higher in CagA positive patients than in CagA negative patients (P < 0.001). Furthermore, mean VAS score was significantly higher in H. pylori positive patients (P = 0.031) and CagA positive patients (P = 0.004); however, there were no significant differences in VAS scores between patients with positive and negative fecal H. pylori antigen (P = 0.310). CONCLUSION: Follow-up and examination of RA patients in terms of infection with serum and fecal H. pylori organism and CagA seems necessary that will contribute to better and further control and treatment of the patients.