First Line Anti-Tuberculosis Drug Resistance Among Human Immunodeficiency Virus Infected Patients Attending Maryland Comprehensive Care Centre Mathare 4a Nairobi Kenya

TB is a major cause of death among people living with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). Multi drug resistant tuberculosis (MDR-TB) accounts for up to 14 % of all these T.B cases

Determining First Line Anti-Tuberculosis Drug Resistance among New and Re-treatment Tuberculosis/ Human Immunodeficiency Virus Infected Patients, Nairobi Kenya

Drug resistant tuberculosis (T.B) is a state when Mycobacterium tuberculosis (MTB) organisms are resistant to antimicrobial agents at the levels attainable in blood and tissue. Scarce data exists on the prevalence of resistance to first line anti-tuberculosis drugs in populations with high rates of tuberculosis and human immunodeficiency virus (H.I.V). Strains of MTB complex from MGIT were subjected to drug susceptibility testing for isoniazid (INH), Rifampicin (R), Streptomycin(S), and Ethambutol (E) using the proportional method on (MGIT). A total of 145 TB patients were enrolled for study. Of the 138 patients who had valid results for analysis, 79(57.2%) were male and 59(42.8%) were female. Most of the patients (20.3%) were aged between 35-39 years with the lowest proportion (3.6%) being in the younger category <20 years. Among the pulmonary tuberculosis patients 34% were new cases while 66% were retreatment cases. A total of 43(31.2%) strains showed resistance to at least one drug tested, while 112(81.2%) were susceptible. The isolates showed different resistance patterns with mono-resistance in 15(11%) isolates, total multi- drug resistance (MDR) in 6(4.3%) isolates with new and retreatment cases being 0(0.0%) and 6(6.6%) respectively. Mono-resistance was recorded in all four drugs tested. The isolates were resistant to the antibiotics as follows; 16(17.6% and 0(0.0%) were resistant to INH; 9(9.9%) and 0(0.0%) were resistant to R; 10(11.0%) and INH (2.1%) were resistant to E; 7(7.7%) and 0(0.0%) were resistant to S; 6(6.6%) and 0(0.0%) were multi drug resistant among retreatment and new cases respectively. Our study concluded that there were high levels of drug resistance among those previously treated for TB

An ovine model of hyperdynamic endotoxemia and vital organ metabolism

BACKGROUND: Animal models of endotoxemia are frequently used to understand the pathophysiology of sepsis and test new therapies. However, important differences exist between commonly used experimental models of endotoxemia and clinical sepsis. Animal models of endotoxemia frequently produce hypodynamic shock in contrast to clinical hyperdynamic shock. This difference may exaggerate the importance of hypoperfusion as a causative factor in organ dysfunction. This study sought to develop an ovine model of hyperdynamic endotoxemia and assess if there is evidence of impaired oxidative metabolism in the vital organs. METHODS: Eight sheep had microdialysis catheters implanted into the brain, heart, liver, kidney and arterial circulation. Shock was induced with a 4hr escalating dose infusion of endotoxin. After 3hrs vasopressor support was initiated with noradrenaline and vasopressin. Animals were monitored for 12hrs after endotoxemia. Blood samples were recovered for haemoglobin, white blood cell count, creatinine and proinflammatory cytokines (IL-1Beta, IL-6 & IL-8). RESULTS: The endotoxin infusion was successful in producing distributive shock with the mean arterial pressure decreasing from 84.5 ± 12.8 mmHg to 49 ± 8.03 mmHg (p < 0.001). Cardiac index remained within the normal range decreasing from 3.33 ± 0.56 l/min/m to 2.89l ± 0.36 l/min/m (p = 0.0845). Lactate/pyruvate ratios were not significantly abnormal in the heart, brain, kidney or arterial circulation. Liver microdialysis samples demonstrated persistently high lactate/pyruvate ratios (mean 37.9 ± 3.3). CONCLUSIONS: An escalating dose endotoxin infusion was successful in producing hyperdynamic shock. There was evidence of impaired oxidative metabolism in the liver suggesting impaired splanchnic perfusion. This may be a modifiable factor in the progression to multiple organ dysfunction and death

Inflammation and lung injury in an ovine model of fluid resuscitated endotoxemic shock

Background Sepsis is a multi-system syndrome that remains the leading cause of mortality and critical illness worldwide, with hemodynamic support being one of the cornerstones of the acute management of sepsis. We used an ovine model of endotoxemic shock to determine if 0.9% saline resuscitation contributes to lung inflammation and injury in acute respiratory distress syndrome, which is a common complication of sepsis, and investigated the potential role of matrix metalloproteinases in this process. Methods Endotoxemic shock was induced in sheep by administration of an escalating dose of lipopolysaccharide, after which they subsequently received either no fluid bolus resuscitation or a 0.9% saline bolus. Lung tissue, bronchoalveolar fluid (BAL) and plasma were analysed by real-time PCR, ELISA, flow cytometry and immunohistochemical staining to assess inflammatory cells, cytokines, hyaluronan and matrix metalloproteinases. Results Endotoxemia was associated with decreased serum albumin and total protein levels, with activated neutrophils, while the glycocalyx glycosaminoglycan hyaluronan was significantly increased in BAL. Quantitative real-time PCR studies showed higher expression of IL-6 and IL-8 with saline resuscitation but no difference in matrix metalloproteinase expression. BAL and tissue homogenate levels of IL-6, IL-8 and IL-1β were elevated. Conclusions This data shows that the inflammatory response is enhanced when a host with endotoxemia is resuscitated with saline, with a comparatively higher release of inflammatory cytokines and endothelial/glycocalyx damage, but no change in matrix metalloproteinase levels

Effects of volume resuscitation on the microcirculation in animal models of lipopolysaccharide sepsis: a systematic review.

BACKGROUND: Recent research has identified an increased rate of mortality associated with fluid bolus therapy for severe sepsis and septic shock, but the mechanisms are still not well understood. Fluid resuscitation therapy administered for sepsis and septic shock targets restoration of the macro-circulation, but the pathogenesis of sepsis is complex and includes microcirculatory dysfunction. OBJECTIVE: The objective of the study is to systematically review data comparing the effects of different types of fluid resuscitation on the microcirculation in clinically relevant animal models of lipopolysaccharide-induced sepsis. METHODS: A structured search of PubMed/MEDLINE and EMBASE for relevant publications from 1 January 1990 to 31 December 2015 was performed, in accordance with PRISMA guidelines. RESULTS: The number of published papers on sepsis and the microcirculation has increased steadily over the last 25 years. We identified 11 experimental animal studies comparing the effects of different fluid resuscitation regimens on the microcirculation. Heterogeneity precluded any meta-analysis. CONCLUSIONS: Few animal model studies have been published comparing the microcirculatory effects of different types of fluid resuscitation for sepsis and septic shock. Biologically relevant animal model studies remain necessary to enhance understanding regarding the mechanisms by which fluid resuscitation affects the microcirculation and to facilitate the transfer of basic science discoveries to clinical applications

Unintended consequences; fluid resuscitation worsens shock in an ovine model of endotoxemia

Background: Fluid resuscitation is widely considered a life saving intervention in septic shock however recent evidence has questioned both its safety and efficacy in sepsis. This study sought to compare fluid resuscitation with vasopressors with vasopressors alone in a hyperdynamic model of ovine endotoxemia. Methods: Endotoxemic shock was induced in sixteen sheep after which they received fluid resuscitation with 40mls/kg of 0.9% saline or commenced haemodynamic support with protocolized noradrenaline and vasopressin. Microdialysis catheters were inserted into the arterial circulation, heart, brain, kidney and liver to monitor local metabolism. Blood samples were recovered to measure serum inflammatory cytokines, creatinine, troponin, ANP, BNP and hyaluronan. All animals were monitored and supported for 12 hours after fluid resuscitation. Results: After resuscitation animals receiving fluid resuscitation required significantly more noradrenaline to maintain the same mean arterial pressure in the subsequent 12 hours (68.9mg vs. 39.6mg p=0.04). Serum cytokines were similar between groups. Atrial natriuretic peptide increased significantly after fluid resuscitation compared to animals managed without fluid resuscitation (335ng/mL (256-382) vs. 233ng/mL (144 – 292) p 0.04). Cross-sectional time series analysis showed the rate of increase of the glycocalcyx glycosaminoglycan hyaluronan was greater in the fluid resuscitated group over the course of the study (p=0.02) Conclusion: Fluid resuscitation resulted in a paradoxical increase in vasopressor requirement. Additionally, It did not result in improvements in any of the measured microcirculatory or organ specific markers measured. The increase in vasopressor requirement seen may have been due to endothelial/glycocalyx damage secondary to ANP mediated glycocalyx shedding

Compromised right ventricular contractility in an ovine model of heart transplantation following 24 h donor brain stem death

BACKGROUND: Heart failure is an inexorably progressive disease with a high mortality, for which heart transplantation (HTx) remains the gold standard treatment. Currently, donor hearts are primarily derived from patients following brain stem death (BSD). BSD causes activation of the sympathetic nervous system, increases endothelin levels, and triggers significant inflammation that together with potential myocardial injury associated with the transplant procedure, may affect contractility of the donor heart. We examined peri-transplant myocardial catecholamine sensitivity and cardiac contractility post-BSD and transplantation in a clinically relevant ovine model. METHODS: Donor sheep underwent BSD (BSD, n = 5) or sham (no BSD) procedures (SHAM, n = 4) and were monitored for 24h prior to heart procurement. Orthotopic HTx was performed on a separate group of donor animals following 24h of BSD (BSD-Tx, n = 6) or SHAM injury (SH-Tx, n = 5). The healthy recipient heart was used as a control (HC, n = 11). A cumulative concentration-effect curve to (-)-noradrenaline (NA) was established using left (LV) and right ventricular (RV) trabeculae to determine β1-adrenoceptor mediated potency (-logEC50 [(-)-noradrenaline] M) and maximal contractility (Emax). RESULTS: Our data showed reduced basal and maximal (-)-noradrenaline induced contractility of the RV (but not LV) following BSD as well as HTx, regardless of whether the donor heart was exposed to BSD or SHAM. The potency of (-)-noradrenaline was lower in left and right ventricles for BSD-Tx and SH-Tx compared to HC. CONCLUSION: These studies show that the combination of BSD and transplantation are likely to impair contractility of the donor heart, particularly for the RV. For the donor heart, this contractile dysfunction appears to be independent of changes to β1-adrenoceptor sensitivity. However, altered β1-adrenoceptor signalling is likely to be involved in post-HTx contractile dysfunction.</p

Fluid resuscitation with 0.9% saline alters haemostasis in an ovine model of endotoxemic shock

Introduction Fluid resuscitation is a cornerstone of severe sepsis management, however there are many uncertainties surrounding the type and volume of fluid that is administered. The entire spectrum of coagulopathies can be seen in sepsis, from asymptomatic aberrations to fulminant disseminated intravascular coagulation (DIC). The aim of this study was to determine if fluid resuscitation with saline contributes to the haemostatic derangements in an ovine model of endotoxemic shock. Materials and methods Twenty-one adult female sheep were randomly divided into no endotoxemia (n = 5) or endotoxemia groups (n = 16) with an escalating dose of lipopolysaccharide (LPS) up to 4 μg/kg/h administered to achieve a mean arterial pressure below 60 mmHg. Endotoxemia sheep received either no bolus fluid resuscitation (n = 8) or a 0.9% saline bolus (40 mL/kg over 60 min) (n = 8). No endotoxemia, saline only animals (n = 5) underwent fluid resuscitation with a 0.9% bolus of saline as detailed above. Hemodynamic support with vasopressors was initiated if needed, to maintain a mean arterial pressure (MAP) of 60-65 mm Hg in all the groups. Results Rotational thromboelastometry (ROTEM®) and conventional coagulation biomarker tests demonstrated sepsis induced derangements to secondary haemostasis. This effect was exacerbated by saline fluid resuscitation, with low pH (p = 0.036), delayed clot initiation and formation together with deficiencies in naturally occurring anti-coagulants antithrombin (p = 0.027) and Protein C (p = 0.001). Conclusions Endotoxemia impairs secondary haemostasis and induces changes in the intrinsic, extrinsic and anti-coagulant pathways. These changes to haemostasis are exacerbated following resuscitation with 0.9% saline, a commonly used crystalloid in clinical settings

Brain stem death induces pro-inflammatory cytokine production and cardiac dysfunction in sheep model.

INTRODUCTION: Organs procured following brain stem death (BSD) are the main source of organ grafts for transplantation. However, BSD is associated with inflammatory responses that may damage the organ and affect both the quantity and quality of organs available for transplant. Therefore, we aimed to investigate plasma and bronchoalveolar lavage (BAL) pro-inflammatory cytokine profiles and cardiovascular physiology in a clinically relevant 6-hour ovine model of BSD. METHODS: Twelve healthy female sheep (37‒42 Kg) were anaesthetized and mechanically ventilated prior to undergoing BSD induction and then monitored for 6 hours. Plasma and BAL endothelin-1 and cytokines (IL-1β, 6, 8 and tumour necrosis factor alpha (TNF-α)) were assessed by ELISA. Differential white blood cell counts were performed. Cardiac function during BSD was also examined using echocardiography, and cardiac biomarkers (A-type natriuretic peptide and troponin I were measured in plasma. RESULTS: Plasma concentrations big ET-1, IL-6, IL-8, TNF-α and BAL IL-8 were significantly (p < 0.01) increased over baseline at 6 hours post-BSD. Increased numbers of neutrophils were observed in the whole blood (3.1×109 cells/L [95% confidence interval (CI) 2.06 - 4.14] vs. 6×109 cells/L [95%CI 3.92 - 7.97]; p < 0.01) and BAL (4.5×109 cells/L [95%CI 0.41 - 9.41] vs. 26 [95%CI 12.29 - 39.80]; p=0.03) after 6 hours of BSD induction vs baseline. A significant increase in ANP production (20.28 pM [95%CI 16.18 - 24.37] vs. 78.68 pM [95%CI 53.16 - 104.21];p < 0.0001) and cTnI release (0.039 ng/mL vs. 4.26 [95%CI 2.69 - 5.83] ng/mL; p < 0.0001), associated with a significant reduction in heart contractile function, were observed between baseline and 6 hours. CONCLUSIONS: BSD induced systemic pro-inflammatory responses, characterized by increased neutrophil infiltration and cytokine production in the circulation and BAL fluid, and associated with reduced heart contractile function in ovine model of BSD