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.

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.

Electronic laboratory system reduces errors in National Tuberculosis Program: a cluster randomized controlled trial.

OBJECTIVE: To evaluate the impact of the e-Chasqui laboratory information system in reducing reporting errors compared to the current paper system. DESIGN: Cluster randomized controlled trial in 76 health centers (HCs) between 2004 and 2008. METHODS: Baseline data were collected every 4 months for 12 months. HCs were then randomly assigned to intervention (e-Chasqui) or control (paper). Further data were collected for the same months the following year. Comparisons were made between intervention and control HCs, and before and after the intervention. RESULTS: Intervention HCs had respectively 82% and 87% fewer errors in reporting results for drug susceptibility tests (2.1% vs. 11.9%, P = 0.001, OR 0.17, 95%CI 0.09-0.31) and cultures (2.0% vs. 15.1%, P < 0.001, OR 0.13, 95%CI 0.07-0.24), than control HCs. Preventing missing results through online viewing accounted for at least 72% of all errors. e-Chasqui users sent on average three electronic error reports per week to the laboratories. CONCLUSIONS: e-Chasqui reduced the number of missing laboratory results at point-of-care health centers. Clinical users confirmed viewing electronic results not available on paper. Reporting errors to the laboratory using e-Chasqui promoted continuous quality improvement. The e-Chasqui laboratory information system is an important part of laboratory infrastructure improvements to support multidrug-resistant tuberculosis care in Peru.

Cost and implementation analysis of a personal digital assistant system for laboratory data collection.

SETTING: One hundred and twenty-six public health centers and laboratories in Lima, Peru, without internet. BACKGROUND: We have previously shown that a personal digital assistant (PDA) based system reduces data collection delays and errors for tuberculosis (TB) laboratory results when compared to a paper system. OBJECTIVE: To assess the data collection efficiency of each system and the resources required to develop, implement and transfer the PDA-based system to a resource-poor setting. DESIGN: Time-motion study of data collectors using the PDA-based and paper systems. Cost analysis of developing, implementing and transferring the PDA-based system to a local organization and their redeployment of the system. RESULTS: Work hours spent collecting and processing results decreased by 60% (P < 0.001). Users perceived this decrease to be 70% and had no technical problems they failed to fix. The total cost and time to develop and implement the intervention was US$26092 and 22 weeks. The cost to extend the system to cover nine more districts was $1125 and to implement collecting patient weights was $4107. CONCLUSION: A PDA-based system drastically reduced the effort required to collect TB laboratory results from remote locations. With the framework described, open-source software and local development, organizations in resource-poor settings could reap the benefits of this technology.

alpha-MeGlc and D-glucose transport by hepatopancreatic brush border membrane vesicles from prawn.

Sugar transport by prawn (Penaeus japonicus) hepatopancreatic epithelium has been studied. Brush-border membrane vesicles (hBBMV) were isolated, studies of osmotic reactivity were made indicating that these vesicles were closed and with low contamination from basolateral membranes. Incubation of hBBMV in the presence of Na+ resulted in rapid sugar uptake by the vesicles with an overshoot at 5 min, achieving the equilibrium value at 60 min. The absence of Na+ or the presence of phloridzin inhibited the overshoot. This uptake appears to be dependent on the membrane potential, since K+ efflux down its concentration gradient in the presence of valinomycin accelerated sugar influx and increased the overshoot when K+-loaded hBBMV were used. The kinetic study of Na+-dependent sugar uptake reveals that values of Km and Vmax were of the same order of magnitud as those described for other absorptive epithelia.

Folate transport by prawn hepatopancreas brush-border membrane vesicles.

The transport system of folic acid (Pte-Glu) by brush-border membrane vesicles (BBMV) isolated from prawn (Penaeus japonicus) hepatopancreas, was studied by measuring the uptake of Pte-Glu. This uptake was found to have two components, intravesicular transport and membrane binding. Membrane binding was not affected by the presence of a transmembrane pH-gradient at a short incubation period. However, a transmembrane pH-gradient increased membrane binding at 60 min. The transport of Pte-Glu appeared to be carrier-mediated, was stimulated by an inwardly proton gradient (pH 5.5 outside, 7.4 inside) and was unaffected by a sodium-gradient. The relationship between pH gradient-driven Pte-Glu uptake and medium Pte-Glu concentration followed saturating Michaelis-Menten kinetics. Eadie-Hofstee representation of the pH gradient-driven Pte-Glu uptake indicated a single transport system with a Km of 0.37 microM and Vmax of 1.06 pmol/mg protein/15 s. These findings indicate that BBMV isolated from prawn hepatopancreas possesses a Pte-Glu transport system similar to that described in mammalian intestine.

Phospholipid fatty acid composition of hepatopancreatic brush-border membrane vesicles from the prawn Penaeus japonicus.

Brush-border membrane vesicles (BBMV) were isolated from prawn hepatopancreas as we previously described (Muriana et al (1993) J Biochem 113, 625-629). The characterization of hepatopancreatic BBMV (hBBMV) by monitoring the activity of marker enzymes indicated a relatively pure apical membrane preparation reduced in basolateral contamination. Phospholipid composition of hBBMV was examined by the Iatroscan TLC/FID technique, whereas the fatty acid profile of phospholipids was examined by capillary gas chromatography. Phosphatidylcholine and phosphatidylethanolamine are the principal phospholipids of these membranes. The major fatty acids of phospholipids are palmitic (16:0), palmitoleic (16:1n-7), stearic (18:0), oleic (18:1n-9), eicosapentaenoic (20:5n-3) and docosapentaenoic (22:5n-3) acids. Individual phospholipids are characterized by distinct fatty acid compositions, but display a similar ratio of unsaturated-to-saturated fatty acids and a similar unsaturation index.

Lipid and fatty acid composition of hepatopancreatic brush-border membrane vesicles from the prawn Penaeus japonicus.

Brush-border membrane vesicles (BBMV) were isolated from prawn hepatopancreas by a procedure involving Mg2+ preparation. The lipid composition of hepatopancreatic BBMV (hBBMV) was examined by the Iatroscan TLC/FID technique, and the fatty acid profile of total lipids was determined by capillary gas chromatography. hBBMV were characterized by a high content of phospholipids and cholesterol. However, the cholesterol/phospholipid molar ratio is lower in prawn than in vertebrate BBMV, which agrees well with the membrane fluidity of BBMV from different sources. The fatty acid composition of hBBMV was similar to that in marine crustacean oils. The major fatty acids present were palmitic (16:0), palmitoleic (16:1n-7), stearic (18:0), oleic (18:1n-9), and eicosapentaenoic (20:5n-3) acids. The large amount of long-chain polyunsaturated fatty acids seems to be related to a high delta 5-desaturase activity in hBBMV.