Silver Nanoparticles-Composing Alginate/Gelatine Hydrogel Improves Wound Healing In Vivo.

Polymer hydrogels have been suggested as dressing materials for the treatment of cutaneous wounds and tissue revitalization. In this work, we report the development of a hydrogel composed of natural polymers (sodium alginate and gelatin) and silver nanoparticles (AgNPs) with recognized antimicrobial activity for healing cutaneous lesions. For the development of the hydrogel, different ratios of sodium alginate and gelatin have been tested, while different concentrations of AgNO3 precursor (1.0, 2.0, and 4.0 mM) were assayed for the production of AgNPs. The obtained AgNPs exhibited a characteristic peak between 430-450 nm in the ultraviolet-visible (UV-Vis) spectrum suggesting a spheroidal form, which was confirmed by Transmission Electron Microscopy (TEM). Fourier Transform Infra-red (FT-IR) analysis suggested the formation of strong intermolecular interactions as hydrogen bonds and electrostatic attractions between polymers, showing bands at 2920, 2852, 1500, and 1640 cm-1. Significant bactericidal activity was observed for the hydrogel, with a Minimum Inhibitory Concentration (MIC) of 0.50 µg/mL against Pseudomonas aeruginosa and 53.0 µg/mL against Staphylococcus aureus. AgNPs were shown to be non-cytotoxic against fibroblast cells. The in vivo studies in female Wister rats confirmed the capacity of the AgNP-loaded hydrogels to reduce the wound size compared to uncoated injuries promoting histological changes in the healing tissue over the time course of wound healing, as in earlier development and maturation of granulation tissue. The developed hydrogel with AgNPs has healing potential for clinical applications.

Clinical presentation of children with pulmonary tuberculosis: 25 years of experience in Lima, Peru.

OBJECTIVE: To describe clinical presentation across age groups in 2855 children with pulmonary tuberculosis (TB) attending the Children's Hospital, Lima, Peru, to improve the diagnosis, treatment and care of childhood TB. DESIGN: Children aged 0-14 years admitted between 1 January 1973 and 31 December 1997 with active pulmonary TB were enrolled. Demographic information, history, physical examination data, laboratory and microbiological results, chest radiograph data, disease classification, treatment and adverse effect data, and outcome at the time of discharge were recorded by pulmonologists using detailed chart abstractions. RESULTS: Of the 2855 enrollees, 47% were malnourished and 56% had a household contact. Older children presented with classic TB symptoms, while weight loss and anorexia were rare in children aged <5 years. Microbiological or pathologic confirmation was obtained in 71% of children aged 10-14 years compared with 34% of children aged <2 years; however, severe extra-pulmonary TB was most common among children aged <2 years (41%). CONCLUSION: Classic TB symptoms should be considered when making a diagnosis; however, systematic symptoms among young children are also important. In high-burden settings, clinicians should have a low threshold to diagnose and treat children for TB across all ages, even in the context of a negative tuberculin skin test result and lack of micro-pathological confirmation.

Dose-response association between salivary cotinine levels and Mycobacterium tuberculosis infection.

SETTING: Tijuana, Mexico. OBJECTIVE: To describe the association between salivary cotinine levels and interferon-gamma (IFN-γ) release assay results. DESIGN: We conducted a cross-sectional study among injection drug users. Salivary cotinine levels were measured using NicAlert, a semi-quantitative dipstick assay. QuantiFERON©-TB Gold In-Tube (QFT-GIT) was used to determine Mycobacterium tuberculosis infection. RESULTS: Among 234 participants, the prevalence of QFT-GIT positivity for NicAlert cotinine categories 0 (non-smoking), 1 (second-hand smoke exposure or low-level smoking) and 26 (regular smoking) were respectively 42.1%, 46.4% and 65.2% (Ptrend 0.012). We found increasing trends in QFT-GIT positivity (Ptrend 0.003) and IFN-γ concentrations (Spearman's r 0.200, P 0.002) across cotinine levels 0 to 6. In multivariable log-binomial regression models adjusted for education, cotinine levels were not associated with QFT-GIT positivity when included as smoking categories (1 and 26 vs. 0), but were independently associated with QFT-GIT positivity when included as an ordinal variable (prevalence ratio 1.09 per 1 cotinine level, 95%CI 1.021.16). CONCLUSION: Our findings suggest that a dose-response relationship exists between tobacco smoke exposure and M. tuberculosis infection. Longitudinal studies that use biochemical measures for smoking status are needed to confirm our findings.

Clinical characteristics, drug resistance, and treatment outcomes among tuberculosis patients with diabetes in Peru.

OBJECTIVES: Diabetes is a risk factor for active tuberculosis (TB). Data are limited regarding the association between diabetes and TB drug resistance and treatment outcomes. We examined characteristics of TB patients with and without diabetes in a Peruvian cohort at high risk for drug-resistant TB. Among TB patients with diabetes (TB-DM), we studied the association between diabetes clinical/management characteristics and TB drug resistance and treatment outcomes. METHODS: During 2005-2008, adults with suspected TB with respiratory symptoms in Lima, Peru, who received rapid drug susceptibility testing (DST), were prospectively enrolled and followed during treatment. Bivariate and Kaplan-Meier analyses were used to examine the relationships of diabetes characteristics with drug-resistant TB and TB outcomes. RESULTS: Of 1671 adult TB patients enrolled, 186 (11.1%) had diabetes. TB-DM patients were significantly more likely than TB patients without diabetes to be older, have had no previous TB treatment, and to have a body mass index (BMI) >18.5 kg/m(2) (p<0.05). In patients without and with previous TB treatment, the prevalence of multidrug-resistant TB was 23% and 26%, respectively, among patients without diabetes, and 12% and 28%, respectively, among TB-DM patients. Among 149 TB-DM patients with DST results, 104 (69.8%) had drug-susceptible TB and 45 (30.2%) had drug-resistant TB, of whom 29 had multidrug-resistant TB. There was no association between diabetes characteristics and drug-resistant TB. Of 136 TB-DM patients with outcome information, 107 (78.7%) had a favorable TB outcome; active diabetes management was associated with a favorable outcome. CONCLUSIONS: Diabetes was common in a cohort of TB patients at high risk for drug-resistant TB. Despite prevalent multidrug-resistant TB among TB-DM patients, the majority had a favorable TB treatment outcome.

Impact of rapid drug susceptibility testing for tuberculosis: program experience in Lima, Peru.

SETTING: Programmatic implementation of decentralized rapid drug susceptibility testing (DST) in Lima, Peru. OBJECTIVE: Pre-post analysis compared time to diagnosis, treatment outcome and survival among patients tested with direct nitrate reductase assay (NRA) vs. indirect conventional methods. DESIGN: From 2005 to 2009, we prospectively followed all patients referred for DST before (control) and after (intervention) NRA implementation. Among those referred for DST, NRA was used for smear-positive samples of patients with no prior history of multidrug resistance or treatment for multidrug-resistant tuberculosis (TB). Data were abstracted from patient charts and laboratory registers. Endpoints were favorable outcomes, time to result and time to death. RESULTS: Of those patients who met the criteria for NRA, 740 underwent NRA and 621 underwent conventional DST. NRA yielded test results for 78.4% of cases vs. 68.8% for conventional DST (P < 0.0001); the median time to result was 44 vs. 133 days, respectively (adjusted HR 0.64, 95%CI 0.56-0.73). Among individuals without previous anti-tuberculosis treatment, NRA was associated with a favorable treatment outcome (adjusted OR 1.39, 95%CI 1.01-1.90) and prolonged survival (adjusted HR 0.53, 95%CI 0.31-0.90). CONCLUSION: Direct NRA significantly shortened time to test result and improved treatment outcomes and survival in certain groups.

HIV-positive patients treated for multidrug-resistant tuberculosis: clinical outcomes in the HAART era.

SETTING: Multidrug-resistant tuberculosis (MDR-TB) and the human immunodeficiency virus (HIV) pose two of the greatest threats to global tuberculosis (TB) control. Given expanding global access to antiretroviral therapy (ART) and second-line TB drugs, more data are needed on experiences treating MDR-TB and HIV co-infection in resource-poor settings. OBJECTIVE: To describe the clinical characteristics, management, outcomes, and factors associated with survival among HIV-positive individuals receiving treatment for MDR-TB. DESIGN: This was a retrospective case series of 52 HIV-positive individuals receiving treatment for MDR-TB in Lima, Peru. We used Cox proportional hazards regression models to identify risk factors for mortality. RESULTS: A total of 31 (57%) of the cohort died on treatment, with the majority of deaths due to MDR-TB. Low baseline weight predicted a three-fold increased rate of death (aHR 3.1, 95%CI 1.5-6.7), while individuals receiving highly active ART experienced a significantly lower rate of death compared to those who were not (aHR 0.4, 95%CI 0.2-0.9). CONCLUSION: Early ART is likely a key component of effective MDR-TB management in co-infected individuals.

Programmatic management of multidrug-resistant tuberculosis: models from three countries.

BACKGROUND: Although multidrug-resistant tuberculosis (MDR-TB) is a major global health problem, there is a gap in programmatic treatment implementation. METHODS: This study describes MDR-TB treatment models in three countries--Peru, Russia and Lesotho-- using qualitative data collected over a 13-year period. RESULTS: A program analysis is presented for each country focusing on baseline medical care, initial implementation and program evolution. A pattern analysis revealed six overarching themes common to all three programs: 1) importance of baseline assessments, 2) early identification of key collaborators, 3) identification of initial locus of care, 4) minimization of patient-incurred costs, 5) targeted interventions for vulnerable populations and 6) importance of technical assistance and funding. Site commonalities and differences in each of these areas were analyzed. CONCLUSIONS: It is recommended that all programs providing MDR-TB treatment address these six areas during program development and implementation.

Health care utilization and costs of a support program for patients living with the human immunodeficiency virus and tuberculosis in Peru.

OBJECTIVE: To evaluate a support program for patients co-infected with the human immunodeficiency virus and tuberculosis in terms of its impact on clinical outcomes and resource utilization. METHODS: We compared co-infected patients receiving Community-Based Accompaniment with Supervised Antiretrovirals (CASA) with matched patients receiving standard of care (control group) in two health districts of Lima, Peru. We recorded clinical outcomes, costs of the intervention, and health care utilization by each patient during 24 months of follow-up. RESULTS: There were 33 patients in each group, representing 58.0 person-years (py) in the CASA group and 45.6 py in the control group. At 24 months of follow-up, the CASA group had a lower hazard of dying or defaulting from treatment (HR adj 0.34, 95%CI 0.12-0.98), experienced fewer hospital days (IRR adj 0.37, 95%CI 0.14-0.99) and had fewer out-patient visits (IRR adj 0.75, 95%CI 0.63-0.89). Assigning costs to significantly different measures of health care utilization using WHO-CHOICE (World Health Organization-Choosing interventions that are cost effective) data, CASA was associated with savings of US$551/py. Considering intervention costs of US$2097/py, the net costs of CASA were US$1546/py. CONCLUSIONS: Our intervention was associated with clinical improvements and reduced health care utilization, which significantly offset the cost of the intervention over 2 years of follow-up.

Assessing spatiotemporal patterns of multidrug-resistant and drug-sensitive tuberculosis in a South American setting.

We examined the spatiotemporal distribution of laboratory-confirmed multidrug-resistant tuberculosis (MDR TB) cases and that of other TB cases in Lima, Peru with the aim of identifying mechanisms responsible for the rise of MDR TB in an urban setting. All incident cases of TB in two districts of Lima, Peru during 2005-2007 were included. The spatiotemporal distributions of MDR cases and other TB cases were compared with Ripley's K statistic. Of 11,711 notified cases, 1187 received drug susceptibility testing and 376 were found to be MDR. Spatial aggregation of patients with confirmed MDR disease appeared similar to that of other patients in 2005 and 2006; however, in 2007, cases with confirmed MDR disease were found to be more tightly grouped. Subgroup analysis suggests the appearance of resistance may be driven by increased transmission. Interventions should aim to reduce the infectious duration for those with drug-resistant disease and improve infection control.

Programmatic implementation of rapid DST for Mycobacterium tuberculosis in Peru.

BACKGROUND: Performance characteristics of novel rapid drug susceptibility tests (DST) for Mycobacterium tuberculosis may change when moving from research to implementation in actual public health practice. We describe the performance characteristics of a direct, rapid DST when implemented in Lima, Peru. METHODS: A district laboratory validated conventional proportions and nitrate reductase methods. We collected data on samples submitted for DST from January 2005 to June 2007 and calculated frequency of testing and results, and median time to test results. RESULTS: A total of 4102 DSTs were performed by conventional DST and 895 by nitrate reductase. Results were obtained from 72.8% of samples by conventional DST and from 70.2% of those processed by Griess; respectively 26.4% and 31.5% were multidrug-resistant tuberculosis. The median time from sample collection to test result was 31 days for Griess vs. 99 days for conventional DST. CONCLUSIONS: Preliminary experience with the Griess method demonstrates favorable performance under program conditions.

Expanding global HIV treatment: case studies from the field.

In the last 25 years, human immunodeficiency virus (HIV) has become the leading infectious killer of adults globally, with an estimated 44 million people infected with the virus worldwide. Most of these individuals live in poor regions of the world, particularly sub-Saharan Africa. Although a great deal of work has been done in identifying and treating individuals with the disease, there has been little action to date to address the complex socioeconomic factors that lie at the heart of this global pandemic. Understanding and responding to such factors is of paramount importance if HIV infection is to be managed in a meaningful way. This article explores the social context of people living with HIV in three different geographic and epidemiologic settings and highlights the social factors that shape and define an individual's risk of acquiring HIV. It also discusses unique programs aimed at addressing the complex realities of the world in which HIV thrives. These programs can act as models of HIV prevention and treatment.

Nurses as providers of emotional support to patients with MDR-TB.

AIM: To identify the forms and means of emotional support that nurses provide to patients living with multidrug-resistant tuberculosis (MTR-TB) in Lima, Peru. BACKGROUND: A fundamental role of nurses is to provide emotional support, defined as all the strategies that a health team employs to assure the psychosocial well-being of the patient. However, neither the forms of emotional support nor the means used by nurses in resource-poor settings have been much written about. This paper describes a qualitative study of a team of seven nurses working in a programme that provides individualized MDR-TB treatment to patients in Lima, Peru. It describes the various forms of support that facilitated the ability of patients to adhere to treatment despite socio-economic difficulties, social stigma, drug side effects, problems related to different stages of treatment and concurrent illnesses/special situations. METHODS: Qualitative study methods were employed over the course of 8 years to observe nurses and patients in an MDR-TB treatment programme. These included participant observation, structured observation sessions of nurses with their patients and focus groups with seven nurses. CONCLUSION: Through theme and content analyses of qualitative data, ten situations related to MDR-TB treatment were found. These ten issues served as an analytical framework used to identify and discuss the various types of emotional support provided by both formal and informal means. This type of support focused on problems related to different stages of treatment, social stigma of the illness, treatment adherence, side effects, socio-economic difficulties, death and concurrent illnesses/special situations. PRACTICE IMPLICATIONS: The essential role of the nurse as a provider of emotional support in the development or implementation of similar programmes with MDR-TB should, in future, be taken into account.

Timely diagnosis of MDR-TB under program conditions: is rapid drug susceptibility testing sufficient?

Timely diagnosis and effective, safe treatment are essential to reduce transmission and improve outcomes for patients with tuberculosis. Aside from laboratory methods, many programmatic factors influence the overall turnaround time (TAT) in diagnosing multidrug-resistant tuberculosis (MDR-TB). We measured each step in the overall TAT required for MDR-TB in two of five health districts of Lima, Peru. The total TAT, from initial sputum specimen to diagnosis and appropriate treatment, was 5 months, almost twice as long as the bacteriological procedures per se. Expensive investments in laboratory technology may yield low returns unless the programmatic aspects of the diagnostic process are streamlined at the same time.

Validation of a rapid method for detection of M. tuberculosis resistance to isoniazid and rifampin in Lima, Peru.

SETTING: Treatment of multidrug-resistant tuberculosis (MDR-TB) is often based on drug susceptibility testing (DST) results; for this reason, rapid, simple DST methods are sought which could be applied in resource-poor countries. One such method is a nitrate reductase colorimetric assay known as the Griess method. In Peru, where the incidence rate of TB is among the highest in South America, the National Institute of Health recently undertook the validation and implementation of the direct Griess method. OBJECTIVE: To describe the process of validation and implemention of the direct Griess method at the Peruvian National Institute of Health. DESIGN: Prospective study comparing the sensitivity and specificity of the direct Griess method with the Löwenstein-Jensen proportion method in determining resistance to isoniazid (INH) and rifampin (RMP) among clinical isolates. RESULTS: Among 192 specimens, the sensitivity and specificity of the Griess method for detection of INH resistance was 99.1% and 100%, respectively. For identification of RMP resistance, the sensitivity and specificity was 93.5% and 100%, respectively. CONCLUSIONS: In addition to its high sensitivity and specificity and rapid turn around time, the Griess method uses simple, inexpensive reagents and requires minimal laboratory space and technical expertise, thus providing an ideal screening tool for resource-poor settings with high rates of MDR-TB.

rpoB gene mutations in clinical isolates of multidrug-resistant Mycobacterium tuberculosis in northern Lima, Peru.

In many developing countries and outside hospital settings, the characteristics of endemic Mycobacterium tuberculosis strains resistant to multiple drugs remain unknown. In a community-based referral and therapy program in northern Lima, Peru, beginning in 1996, patients found to be failures on standard regimens were referred for drug-susceptibility testing of their isolates, and those found to be infected with M. tuberculosis isolates resistant to at least rifampin were treated with individualized regimens based on their infecting strains. Isolates from 42 of these patients were subjected to DNA sequencing of the rpoB gene region responsible for rifampin resistance. We determined the frequency of types of mutations in the rpoB gene among these Peruvian isolates.

Psychiatric issues in the management of patients with multidrug-resistant tuberculosis.

INTRODUCTION: Psychiatric issues present a challenge in the treatment of patients with multidrug-resistant tuberculosis (MDR-TB). Both baseline psychiatric disorders and development of psychiatric complications related to anti-tuberculosis drugs and psychosocial factors require aggressive management. SETTING: A community-based non-governmental health organization in Lima, Peru. OBJECTIVE: To review the literature for psychiatric complications associated with anti-tuberculosis medications, to describe the incidence and prevalence of depression, anxiety and psychosis among individuals receiving MDR-TB therapy, and to detail the management approach used in this cohort. METHODS: A retrospective case series was performed among the first 75 patients to receive individualized MDR-TB therapy in Lima, Peru, between 1996 and 1999. RESULTS: Baseline depression and baseline anxiety were observed in respectively 52.2% and 8.7% of this cohort. Most individuals with baseline depression experienced improvement of depressive symptoms during the course of TB therapy. The incidence of depression, anxiety and psychosis during MDR-TB treatment was 13.3%, 12.0% and 12.0%, respectively. While the majority of individuals with depression, anxiety and psychosis required psychiatric pharmacotherapy, cycloserine was successfully continued in all but one case. CONCLUSION: Psychiatric comorbidities are not a contra-indication to MDR-TB therapy. Management of psychiatric complications is possible without compromising anti-tuberculosis treatment.

Clinical and programmatic considerations in the treatment of MDR-TB in children: a series of 16 patients from Lima, Peru.

SETTING: Since 2000, the directly observed treatment, short-course (DOTS) strategy has been expanded in several countries to include treatment of multidrug-resistant tuberculosis (MDR-TB). This strategy is known as DOTS-Plus. Tuberculosis is a common cause of morbidity and mortality for children throughout the developing world. Children may also be infected with MDR-TB, yet most developing countries do not specifically address pediatric MDR-TB. OBJECTIVE: To present the intermediate outcomes of the first 16 children enrolled in the Peruvian DOTS-Plus program and to demonstrate the tolerability of second-line anti-tuberculosis drugs. RESULTS: Three children completed therapy and are cured, one child had bacteriologic and clinical failure after 12 months of therapy and died of respiratory insufficiency, and 12 have intermediate outcomes demonstrating favorable clinical, bacteriologic, and radiographic evidence of improvement after 9-19 months of therapy. CONCLUSIONS: Of the 16 pediatric DOTS-Plus patients, 15 have tolerated therapy well and have had favorable clinical evolution. However, the diagnosis of pediatric MDR-TB is often extremely delayed due to reliance on the adult case definition and should be changed to prevent progressive, chronic illness in such children. Programmatic changes could facilitate earlier diagnosis and treatment of pediatric MDR-TB in Peru and in other DOTS-Plus programs.

Peripheral neuropathy associated with treatment for multidrug-resistant tuberculosis.

OBJECTIVE: To review the incidence and management of peripheral neuropathy in patients receiving therapy for MDR-TB. METHODS: A case series with retrospective chart review of 75 patients who initiated individualized therapy for multidrug-resistant tuberculosis (MDR-TB) in Lima, Peru, between 1 August 1996 and 31 January 1999. RESULTS: All patients had confirmed MDR-TB and were receiving individualized therapy, comprised of an average of six drugs. Ten (13%) of these patients presented with symptoms of peripheral neuropathy, confirmed by electromyography. All symptoms were reported in the lower extremities, and all were sensory in nature. Median time to presentation from initiation of MDR-TB therapy was 9.1 months. No significant risk factors associated with development of peripheral neuropathy were identified. Management strategies depended on the severity of symptoms and included the treatment of contributing co-morbidities, medications for neuropathic pain, and adjustment of doses of possible offending agents. All patients responded to management; three patients were left with mild residual symptoms. Patients whose neuropathy resolved had symptoms for a median of 7 months. CONCLUSIONS: Peripheral neuropathy was encountered in 13% of our cohort of MDR-TB patients. The diagnosis of peripheral neuropathy can be based on clinical presentation alone, and effective management of this side-effect is possible without sacrificing MDR-TB treatment efficacy.

Occurrence of serious adverse effects in patients receiving community-based therapy for multidrug-resistant tuberculosis.

SETTING: A community-based treatment program for multidrug-resistant tuberculosis (MDR-TB) in an urban shantytown of Lima, Peru. OBJECTIVES: To ascertain the occurrence of serious adverse effects associated with therapy for MDR-TB in northern Lima, Peru, where therapy was individualized according to drug-susceptibility testing of patients' infecting strains and delivered through a community-based program. DESIGN: A retrospective record review of 60 patients who had received individualized therapy for MDR-TB between September 1996 and October 1998. RESULTS: Although adverse effects were common, they occurred less frequently than previously reported in the literature and were rarely life-threatening. Effects occurring most frequently in this population included: mild gastritis (100%), dermatological effects (43.3%), peripheral neuropathy (16.7%), depression (18.3%), and anxiety (11.7%). These effects never resulted in the discontinuation of anti-tuberculosis therapy, and only occasionally resulted in the suspension of an agent (11.7%). CONCLUSION: In young patients with little comorbid disease, multidrug, long-course regimens rarely caused life-threatening adverse effects. Common side effects may be managed successfully on an out-patient basis through a community-based treatment program in conjunction with MDR-TB experts, even in resource-poor settings. The very low rate of default in this cohort offers hope that strategies to manage the adverse effects may reduce the incidence of abandonment of therapy and increase rates of cure.

Using treatment failure under effective directly observed short-course chemotherapy programs to identify patients with multidrug-resistant tuberculosis.

SETTING: Public ambulatory care centers in three districts of northern metropolitan Lima, Peru. OBJECTIVE: To document drug resistance patterns of isolates of Mycobacterium tuberculosis from patients identified as treatment failures under a model tuberculosis (TB) control program based on directly observed, short-course chemotherapy (DOT-SCC). DESIGN: Case series. RESULTS: In a referred, consecutive sample of 173 patients identified as treatment failures on DOT-SCC, 160 (92.5%) had culture-positive TB. Of those 160, 150 (93.8%) had active, pulmonary multidrug-resistant TB (MDR-TB, resistance to at least isoniazid [INH] and rifampicin [RIF]). Sixty of the 150 (40.0%) had isolates resistant to at least INH, RIF, ethambutol (EMB) and pyrazinamide (PZA), the initial first-line empiric treatment regimen used locally. Forty-four (29.3%) had isolates resistant to at least INH, RIF, EMB, PZA and streptomycin (SM), the first retreatment regimen. This series of patients had isolates resistant to a mean of 4.5 of the ten drugs tested. The local profile of multidrug resistance is very different from that obtained from national data from Peru. CONCLUSION: In this setting, treatment failure on DOT-SCC is strongly predictive of active MDR-TB. Because of existing local drug resistance patterns in northern Lima, 89.3% of MDR-TB patients identified as treatment failures will receive ineffective therapy with two or fewer secondary TB drugs if they are given the five-drug empiric retreatment regimen endorsed by the World Health Organization. Further short-course chemotherapy for these patients would only serve to amplify ominous existing drug resistance patterns.