Emerging Pathogens and Resistance Mechanisms: Shaping Future Pediatric Antimicrobial Resistance

Antimicrobial resistance (AMR) has emerged as one of the most serious global health crises, especially among pediatric populations. MRSA, VRE, and CRE are examples of multidrug-resistant organisms that pose significant challenges in infection management, especially among weak children in intensive care units. Increasing resistance among infections such as Escherichia coli and Klebsiella pneumoniae makes them more challenging to manage. Contributing factors to this problem are the misuse of antibiotics and the lack of pediatric-specific research, calling for comprehensive action. Root causes like the misuse of antibiotics and the lack of pediatric-relevant research are fueling the crisis, and that is why collective action is paramount. Interventions like implementing surveillance networks like the WHO’s Global Antimicrobial Resistance Surveillance System (GLASS) and facilitating antimicrobial stewardship programs (ASPs) age-specific for children, like the effective ASP model at Johns Hopkins Children’s Center, must be undertaken. Public health campaigns, for example, the CDC’s “Get Smart” program, show the power of education in averting the abuse of antibiotics. Treatment attempts are made more difficult by other serious multidrug-resistant pathogens that affect children, particularly in hospital settings, such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Clostridium difficile. To that end, multiple strategies are essential, such as establishing strong surveillance systems and antimicrobial stewardship programs (ASPs) that take into account the pediatric population. Understanding local resistance patterns is central to designing of region-specific public health interventions, especially in low-resource settings, where AMR burdens healthcare systems and threatens their fragile infrastructures. The discovery of genetic factors that cause resistance and the emergence of new drugs will play crucial roles in curbing this evolving threat while improving the well-being of children. A strategic approach to the challenge of AMR in the hospitalized child requires coordinated, multi-pronged efforts-education for health professionals and their families, public campaigns, and improved access to quality medical care. Prescription guidelines strengthened, and more effective surveillance systems should be put in place; targeted educational initiatives will ensure effective management of the rising tide of AMR within healthcare systems. Long-term solutions will only be achieved through collaboration among healthcare providers, policymakers, and researchers. Such collaboration will encourage over time, promote innovation, and ensure that better treatment options are developed. It is also crucial that evidence-based treatments are provided as well as healthcare systems are ready to address the pediatric patients because of the increase in multidrug-resistant like E. coli and Staphylococcus aureus. Commitment to vigilance, education, and innovation will be vital for mitigating AMR risks and protect the most vulnerable populations worldwide. This study focuses on the treatment challenges and adverse clinical outcomes associated with antimicrobial resistance (AMR) in pediatric populations. It highlights the role of resistance mechanisms, emerging pathogens, and the urgent need for targeted stewardship programs to protect child health

Immune reconstitution inflammatory syndrome in association with HIV/AIDS and tuberculosis: Views over hidden possibilities

Gut immune components are severely compromised among persons with AIDS, which allows increased translocation of bacterial lipopolysaccharides (LPS) into the systemic circulation. These microbial LPS are reportedly increased in chronically HIV-infected individuals and findings have correlated convincingly with measures of immune activation. Immune reconstitution inflammatory syndrome (IRIS) is an adverse consequence of the restoration of pathogen-specific immune responses in a subset of HIV-infected subjects with underlying latent infections during the initial months of highly active antiretroviral treatment (HAART). Whether IRIS is the result of a response to a high antigen burden, an excessive response by the recovering immune system, exacerbated production of pro-inflammatory cytokines or a lack of immune regulation due to inability to produce regulatory cytokines remains to be determined. We theorize that those who develop IRIS have a high burden of proinflammatory cytokines produced also in response to systemic bacterial LPS that nonspecifically act on latent mycobacterial antigens. We also hypothesize that subjects that do not develop IRIS could have developed either tolerance (anergy) to persistent LPS/tubercle antigens or could have normal FOXP3+ gene and that those with defective FOXP3+ gene or those with enormous plasma LPS could be vulnerable to IRIS. The measure of microbial LPS, anti-LPS antibodies and nonspecific plasma cytokines in subjects on HAART shall predict the role of these components in IRIS

The PTAP sequence duplication in HIV-1 subtype C Gag p6 in drug-naive subjects of India and South Africa

Abstract Background HIV-1 subtype C demonstrates several biological properties distinct from other viral subtypes. One such variation is the duplication of PTAP motif in p6 Gag. PTAP motif is a key player in viral budding. Here, we studied the prevalence of PTAP motif duplication in subtype C viral strains in a longitudinal study. Methods In a prospective follow-up study, 65 HIV-1 seropositive drug-naive subjects were monitored in two different clinical cohorts of India for 2 years with repeated sampling at 6-month intervals. The viral RNA was extracted from plasma, the gag segment was amplified and sequenced. From a subset of viral isolates the sequences of pol, env and LTR were sequenced. Using HIV-1 gag amino acid sequences available from public databases and additional sequences derived from the Indian and South-African cohorts, we examined the nature of PTAP motif duplication in subtype C. Results In 16% (8 of 50) of the primary viral strains of India, we identified a sequence duplication of the PTAP motif in Gag p6. The length of the sequence duplication varied from 6 to 14 amino acids in the viral isolates but remained fixed within a subject over a period of 24–36 month follow-up. In the duplicated motif, the core PTAP motif was invariable, but the flanking residues were highly variable. In an acute phase clinical cohort of South Africa, in a subset of 75 subjects, we found the presence of the PTAP duplication at a frequency of 29.3%. An analysis of the gag sequences from the extant databases showed that unlike other subtypes of HIV-1, subtype C has a natural propensity to generate the PTAP motif duplication at a significantly higher frequency and of greater length. Additionally, the global prevalence of PTAP duplication in subtype C appears to be increasing progressively over the past 30 years. Conclusion We showed that in subtype C, the duplication of the PTAP motif in p6 Gag involves sequence stretches of greater length, and at a much higher frequency as compared to other HIV-1 subtypes. Given that subtype C naturally lacks the Alix binding motif, the acquisition of an additional PTAP motif may confer replication advantage on this HIV-1 subtype. Further investigation is warranted to examine the significance of PTAP motif duplication on the replicative fitness of HIV-1

Does CD4+CD25+foxp3+ cell (Treg) and IL-10 profile determine susceptibility to immune reconstitution inflammatory syndrome (IRIS) in HIV disease?

HIV-specific T-lymphocyte responses that underlie IRIS are incomplete and largely remain hypothetical. Of the several mechanisms presented by the host to control host immunological damage, Treg cells are believed to play a critical role. Using the available experimental evidence, it is proposed that enormous synthesis of conventional FoxP3- Th cells (responsive) often renders subjects inherently vulnerable to IRIS, whereas that of natural FoxP3+ Treg cell synthesis predominate among subjects that may not progress to IRIS. We also propose that IRIS non-developers generate precursor T-cells with a high avidity to generate CD4+CD25+FoxP3+ Tregs whereas IRIS developers generate T-cells of intermediate avidity yielding Th0 cells and effector T-cells to mediate the generation of proinflammatory cytokines in response to cell-signaling factors (IL-2, IL-6 etc.). Researchers have shown that IL-10 Tregs (along with TGF-β, a known anti-inflammatory cytokine) limit immune responses against microbial antigens in addition to effectively controlling HIV replication, the prime objective of HAART. Although certain technical limitations are described herein, we advocate measures to test the role of Tregs in IRIS

Performance characteristics of an instrument-free point-of-care CD4 test (VISITECTVR CD4) for use in resource-limited settings

Objective: CD4þ T lymphocyte count remains the most common biomarker of immune status and disease progression in human immunodeficiency virus (HIV)-positive individuals. VISITECTVR CD4 is an instrument-free, low-cost point-of-care CD4 test with a cut-off of 350 CD4 cells/lL. This study aimed to evaluate VISITECTVR CD4 test’s diagnostic accuracy. Methods: Two hundred HIV-positive patients attending a tertiary HIV centre in South India were recruited. Patients provided venous blood for reference and VISITECTVR CD4 tests. An additional finger-prick blood sample was obtained for VISITECTVR CD4. VISITECTVR CD4’s diagnostic performance in identifying individuals with CD4 counts 350 cells/lL was assessed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) taking flow cytometry as the reference. Results: The overall agreement between VISITECTVR CD4 and flow cytometry was 89.5% using venous blood and 81.5% using finger-prick blood. VISITECTVR CD4 showed better performance using venous blood [sensitivity: 96.6% (95% confidence interval: 92.1%–98.9%), specificity: 70.9% (57.1%–82.4%), PPV: 89.7% (83.9%–94.0%) and NPV: 88.6% (75.4%–96.2%)] than using fingerprick blood [sensitivity: 84.8% (77.9%–90.2%), specificity: 72.7% (59.0%–83.9%), PPV: 89.1% (82.7%–93.8%) and NPV: 64.5% (51.3%–76.3%)]. Conclusion: VISITECTVR CD4 performed well using venous blood, demonstrating its potential utility in decentralization of CD4 testing services in resource-constrained settings

Establishment of reference CD4+ T cell values for adult Indian population

<p>Abstract</p> <p>Background</p> <p>CD4+ T lymphocyte counts are the most important indicator of disease progression and success of antiretroviral treatment in HIV infection in resource limited settings. The nationwide reference range of CD4+ T lymphocytes was not available in India. This study was conducted to determine reference values of absolute CD4+ T cell counts and percentages for adult Indian population.</p> <p>Methods</p> <p>A multicentric study was conducted involving eight sites across the country. A total of 1206 (approximately 150 per/centre) healthy participants were enrolled in the study. The ratio of male (N = 645) to female (N = 561) of 1.14:1. The healthy status of the participants was assessed by a pre-decided questionnaire. At all centers the CD4+ T cell count, percentages and absolute CD3+ T cell count and percentages were estimated using a single platform strategy and lyse no wash technique. The data was analyzed using the Statistical Package for the Social Scientist (SPSS), version 15) and Prism software version 5.</p> <p>Results</p> <p>The absolute CD4+ T cell counts and percentages in female participants were significantly higher than the values obtained in male participants indicating the true difference in the CD4+ T cell subsets. The reference range for absolute CD4 count for Indian male population was 381-1565 cells/μL and for female population was 447-1846 cells/μL. The reference range for CD4% was 25-49% for male and 27-54% for female population. The reference values for CD3 counts were 776-2785 cells/μL for Indian male population and 826-2997 cells/μL for female population.</p> <p>Conclusion</p> <p>The study used stringent procedures for controlling the technical variation in the CD4 counts across the sites and thus could establish the robust national reference ranges for CD4 counts and percentages. These ranges will be helpful in staging the disease progression and monitoring antiretroviral therapy in HIV infection in India.</p

Predicting resistance as indicator for need to switch from first-line antiretroviral therapy among patients with elevated viral loads: development of a risk score algorithm

Abstract Background In resource-limited settings, where resistance testing is unavailable, confirmatory testing for patients with high viral loads (VL) delays antiretroviral therapy (ART) switches for persons with resistance. We developed a risk score algorithm to predict need for ART change by identifying resistance among persons with persistently elevated VL. Methods We analyzed data from a Phase IV open-label trial. Using logistic regression, we identified demographic and clinical characteristics predictive of need for ART change among participants with VLs ≥1000 copies/ml, and assigned model-derived scores to predictors. We designed three models, including only variables accessible in resource-limited settings. Results Among 290 participants with at least one VL ≥1000 copies/ml, 51 % (148/290) resuppressed and did not have resistance testing; among those who did not resuppress and had resistance testing, 47 % (67/142) did not have resistance and 53 % (75/142) had resistance (ART change needed for 25.9 % (75/290)). Need for ART change was directly associated with higher baseline VL and higher VL at time of elevated measure, and inversely associated with treatment duration. Other predictors included body mass index and adherence. Area under receiver operating characteristic curves ranged from 0.794 to 0.817. At a risk score ≥9, sensitivity was 14.7–28.0 % and specificity was 96.7–98.6 %. Conclusions Our model performed reasonably well and may be a tool to quickly transition persons in need of ART change to more effective regimens when resistance testing is unavailable. Use of this algorithm may result in public health benefits and health system savings through reduced transmissions of resistant virus and costs on laboratory investigations

Expansion of HIV Laboratory Diagnostic Services in Chennai, India 2001–2006: Is the Growth Commensurate with the Need?

Objective: To describe the changes in HIV services provided and the patient population utilizing voluntary counseling and testing (VCT) services at private testing laboratories in Chennai, India in 2001 and 2006. Methods: In 2001, a cross-sectional descriptive survey was conducted to assess the services provided and client population of 1,031 private laboratories. A subset of labs (9%) that had been surveyed in 2001 were also studied in 2006. Results: In 2001, significantly more high volume labs (.10 HIV tests per month) offered HIV diagnostic tests than low volume labs (,10 HIV test per month) (p,0.001). More high volume labs (20.0%) provided pre-test counseling as part of HIV testing than low volume labs (11.1%) (p = 0.003). Between 2001 and 2006, the number of labs that provided HIV diagnostic tests significantly increased, including ELISA (87.8 % vs. 40.0%), Western Blot (84.4 % vs. 13.3%), and Tridot (98.9 % vs. 72.2%) (p,0.001). Also the number of labs that reported greater than 10 women seeking HIV testing per month significantly increased from 14.5 % to 79.0 % (p = 0.006). More labs provided pre-test counseling in 2006 (34.4%) than in 2001 (21.1%) (p = 0.046). Conclusions: Though HIV diagnostic testing services have increasingly become available, counseling services have not expanded commensurately. Further outreach and education is necessary to expand comprehensive HIV VCT services in bot