Correlates and determinants of Early Infant Diagnosis outcomes in North-Central Nigeria.

BACKGROUND: A negative status following confirmatory Early Infant Diagnosis (EID) is the desired pediatric outcome of prevention of Mother to Child Transmission (PMTCT) programs. EID impacts epidemic control by confirming non-infected HIV-exposed infants (HEIs) and prompting timely initiation of ART in HIV-infected babies which improves treatment outcomes. OBJECTIVES: We explored factors associated with EID outcomes among HEI in North-Central Nigeria. METHOD: This is a cross-sectional study using EID data of PMTCT-enrollees matched with results of HEI's dried blood samples (DBS), processed for DNA-PCR from January 2015 through July 2017. Statistical analyses were done using SPSS version 20.0 to generate frequencies and examine associations, including binomial logistic regression with p < 0.05 being statistically significant. RESULTS: Of 14,448 HEI in this analysis, 51.8% were female and 95% (n = 12,801) were breastfed. The median age of the infants at sample collection was 8 weeks (IQR 6-20), compared to HEI tested after 20 weeks of age, those tested earlier had significantly greater odds of a negative HIV result (≤ 6 weeks: OR = 3.8; 6-8 weeks: OR = 2.1; 8-20 weeks: OR = 1.5) with evidence of a significant linear trend (p < 0.001). Similarly, HEI whose mothers received combination antiretroviral therapy (cART) before (OR = 11.8) or during the index pregnancy (OR = 8.4) had significantly higher odds as compared to those whose mothers did not receive cART. In addition, HEI not breastfed had greater odds of negative HIV result as compared to those breastfed (OR = 1.9). CONCLUSIONS: cART prior to and during pregnancy, earlier age of HEI at EID testing and alternative feeding other than breastfeeding were associated with an increased likelihood of being HIV-negative on EID. Therefore, strategies to scale-up PMTCT services are needed to mitigate the burden of HIV among children.

Thermosensitive hydrogel as an in situ gelling antimicrobial ocular dressing.

Microbial keratitis is a severe ocular condition and one of the most prevalent causes of corneal scarring and associated blindness worldwide. Risk factors include contact lens use, ocular trauma, ocular surface disease and immunosuppression. Initial clinical management mandates intensive (hourly or more frequent) topical administration of broad spectrum antimicrobial therapy for at least 48h, which may require hospital admission, followed by tailored therapy based on microbiological investigation and the institution of strategies to reduce inflammation and promote healing. In this work we report an ocular wound dressing which can encapsulate and give sustained release of different antibiotics. The use of this dressing would allow patients to have eye drops on a 4 hourly basis, thereby facilitating treatment compliance and reducing hospital admissions.

Antimicrobial peptide coatings for hydroxyapatite: electrostatic and covalent attachment of antimicrobial peptides to surfaces.

The interface between implanted devices and their host tissue is complex and is often optimized for maximal integration and cell adhesion. However, this also gives a surface suitable for bacterial colonization. We have developed a novel method of modifying the surface at the material-tissue interface with an antimicrobial peptide (AMP) coating to allow cell attachment while inhibiting bacterial colonization. The technology reported here is a dual AMP coating. The dual coating consists of AMPs covalently bonded to the hydroxyapatite surface, followed by deposition of electrostatically bound AMPs. The dual approach gives an efficacious coating which is stable for over 12 months and can prevent colonization of the surface by both Gram-positive and Gram-negative bacteria.

Ciprofloxacin and ceftriaxone alter cytokine responses, but not Toll-like receptors, to Salmonella infection in vitro.

OBJECTIVES: Antibiotics that enhance host natural defences to infection offer an alternative approach to treating infections. However, mechanisms underlying such processes are poorly understood. The aim of this study was to investigate the effects of clinically relevant concentrations of two antibiotics on bacterial interactions with murine macrophages. METHODS: Adhesion of Salmonella Typhimurium SL1344 to and invasion by Salmonella Typhimurium SL1344 of antibiotic-treated or untreated J774 murine macrophages were measured using a tissue culture infection model. Expression of genes central to the Toll-like receptor (TLR) signalling pathway of macrophages infected with Salmonella was analysed using the RT(2) Profiler PCR Array. Cytokine production was measured by ELISA. RESULTS: Adhesion of Salmonella Typhimurium SL1344 to J774 macrophage monolayers was increased when macrophages were exposed to ciprofloxacin and ceftriaxone, while invasion was decreased by ciprofloxacin. Expression of IL-1ß and TNF-α mRNA was greater in SL1344-infected macrophages that had been treated with ciprofloxacin or ceftriaxone than in macrophages exposed to antibiotics alone or SL1344 alone. TLR mRNA was down-regulated by SL1344 infection, a response that was not altered by antibiotic pretreatment. CONCLUSIONS: Clinically relevant concentrations of two antibiotics differentially enhanced the response of immune cells and their interaction with bacteria, increasing bacterial adhesion to macrophages and increasing cytokine production. As increased expression of IL-1ß fosters apoptosis of Salmonella-infected macrophages and clearance by neutrophils, the immunomodulatory potential of these antibiotics may explain, in part, why these two drugs continue to be used to treat salmonellosis successfully.

The immune response and antibacterial therapy.

The host's immune defence mechanisms are indispensable factors in surviving bacterial infections. However, in many circumstances, the immune system alone is inadequate. Since the 1940s, the use of antibacterial therapy has saved millions of lives, improving the span and quality of life of individuals. Unfortunately, we are now facing an era where antibacterial agents are threatened by resistance. In addition to targeting bacteria, some antibacterial agents affect various aspects of the immune response to infection. Since many antibacterial drugs are failing in efficacy due to resistance, it has been strongly suggested that any synergy between these drugs and the immune response be exploited in the treatment of bacterial infections. This review explores the influence of antibacterial therapy on the immune response and new approaches that could exploit this interaction for the treatment of bacterial infections.