Bacteria isolated from bloodstream infections at a tertiary hospital in Dar es Salaam, Tanzania – antimicrobial resistance of isolates

Objective. A bloodstream infection (BSI) is a life-threatening condition. We studied the causative agents of BSIs and antimicrobial susceptibility patterns of bacterial isolates at Muhimbili National Hospital (MNH) in Dar es Salaam, Tanzania. Methods. A retrospective analysis of blood culture results obtained at MNH from January 2005 to December 2009 was done. Blood culture isolates judged to be clinically significant and antimicrobial susceptibility results of the bacteria were included. The frequencies and proportions of bacteria isolated and antimicrobial susceptibility results were analysed and compared using Pearson’s chi-square test and Fisher’s exact test where applicable, or the Mann-Whitney U-test. Results. A total of 13 833 blood cultures were performed. Bacterial pathogens were detected in 1 855 (13.4%), Gram-positive bacteria (1 523; 82.1%) being significantly more prevalent than Gramnegative bacteria (332; 17.9%) (p=0.008). The most common bacterial pathogens isolated were coagulase-negative staphylococci (CoNS) (1 250; 67.4%), S. aureus (245; 13.2%), Escherichia coli (131; 7%) and Klebsiella spp. (130; 7.0%). All bacteria isolated showed high resistance to penicillin G (70.6%), tetracycline (63.8%), cefotaxime (62.5%) and ampicillin (62.3%). Moderate to high resistance was seen against chloramphenicol (45.2%), erythromycin (35.0%), ciprofloxacin (29.3%), co-trimoxazole (25.0%) and gentamicin (23.5%). Of S. aureus isolates, 23.3% were resistant to methicillin. Conclusions. CoNS accounted for two-thirds of the bacterial pathogens isolated. High-level resistance was seen to first-line and inexpensive antimicrobial agents. Routine screening for extendedspectrum beta-lactamase production and methicillin resistance among Gram-negative rods and S. aureus from blood cultures should be instituted to monitor spread of multidrug-resistant isolates

Chemical Polymerization Kinetics of Poly-O-Phenylenediamine and Characterization of the Obtained Polymer in Aqueous Hydrochloric Acid Solution Using K 2

The oxidative chemical polymerization of o-phenylenediamine (OPDA) was studied in hydrochloric acid solution using potassium dichromate as oxidant at 5°C. The effects of potassium dichromate, hydrochloric acid, and monomer concentrations on the polymerization reaction were investigated. The order of reaction with respect to potassium dichromate, hydrochloric acid, and monomer concentration was found to be 1.011, 0.954, and 1.045, respectively. Also, the effect of temperature on the polymerization rate was studied and the apparent activation energy of the polymerization reaction was found to be 63.658 kJ/mol. The obtained polymer was characterized using XPS, IR, UV-visible, and elemental analysis. The surface morphology of the obtained polymers was characterized by X-ray diffraction and transmission electron microscopy (TEM). The TGA analysis was used to confirm the proposed structure and number of water molecules in each polymeric chain unit. The ac conductivity (σac) of (POPDA) was investigated as a function of frequency and temperature. The ac conductivity was interpreted as a power law of frequency. The frequency exponent (s) was found to be less than unity and decreased with the increase of temperature, which confirms that the correlated barrier hopping model was the dominant charge transport mechanism

Iringa Regional and District Projections.

This report presents population projections for the period 2003 to 2025 for Iringa Region and its districts. The projections were made using a Cohort Component Method (Spectrum System), whereby three components responsible for population change, namely: mortality, fertility and migration were projected separately as well as HIV/AIDS prevalence. The projected components were then applied to 2002 midyear base population in order to come up with the desired projections from 2003 to 2025. The report gives mortality, fertility, migration and HIV/AIDS assumptions, and shows Iringa’s demographic and socio-economic future trends. The results include estimated population by sex in single years and five-year age groups as well as some demographic indicators. Population growth for the period 2003 to 2025 shows a decrease in growth rates. The projections show that population growth rate will decrease from 1.6 percent in 2003 (with a population of 1,520,891) to 0.4 percent in 2025 (with a population of 2,019,217). Sex Ratio at birth is projected to increase from 90 male births per 100 females in 2003 to 99 male births per 100 females in 2025. Mortality estimates show that Infant Mortality Rate (IMR) is expected to decline for both sexes from 127 deaths per 1,000 live births in 2003 to 78 deaths per 1,000 live births in 2025. Under Five Mortality Rate (U5MR) for both sexes will also decline from 207 deaths per 1,000 live births in 2003 to 122 deaths per 1,000 live births in the year 2025. The mortality projected estimates further show that the life expectancy at birth for both males and females stands at 45 years in 2003. Life expectancy at birth for Iringa will decline from 45 years in 2003 to 44 years in 2025 for both sexes. For male population, life expectancy at birth will remain at the same level of 45 years in year 2003 and year 2025, while for female population the life expectancy at birth will decline from 45 years in 2003 to 43 years in 2025. On fertility, TFR will decline from 4.9 children per woman in 2003 to 2.6 children per woman in 2025.\u

Dar es Salaam Regional and District Projections.

This report presents population projections for the period 2003 to 2025 for Dar es Salaam Region. The projections were made using a Cohort Component Method (Spectrum System), whereby three components responsible for population change, namely: mortality, fertility and migration were projected separately as well as HIV/AIDS prevalence. The projected components were then applied to 2002 midyear base population in order to come up with the desired projections from 2003 to 2025. The report gives mortality, fertility, migration and HIV/AIDS assumptions, and shows Dar es Salaam’s demographic and socio-economic future trends. The results include estimated population by sex in single years and five-year age groups as well as some demographic indicators. Population growth for the period 2003 to 2025 shows a decrease in growth rates. The projections show that population growth rate will decrease from 1.99 percent in 2003 (with a population of 2,535,594) to 0.27 percent in 2025 (with a population of 3,055,456). Sex Ratio at birth is projected to increase slightly from 102 male per 100 females in 2003 to 103 male per 100 females in 2025. Mortality estimates show that Infant Mortality Rate (IMR) is expected to decline for both sexes from 80 deaths per 1,000 live births in 2003 to 49 deaths per 1,000 live births in 2025. Under Five Mortality Rate (U5MR) for both sexes will also decline from 122 deaths per 1,000 live births in 2003 to 71 deaths per 1,000 live births in the year 2025. As expected, the mortality projected estimates further show that the life expectancy at birth for females is higher compared to that of males. Life expectancy at birth for Dar es Salaam will decline from 55 years in 2003 to 52 years in 2025 for both sexes. For male population, life expectancy at birth will almost remain at 53 years for the whole period. For female population, the life expectancy at birth will decline from 57 years in 2003 to 52 years in 2025. On fertility, TFR will decline from 2.7 children per woman in 2003 to about 2 children per woman in 2025.\u

Predictors of Stunting, Wasting and Underweight among Tanzanian Children Born to HIV-Infected Women.

Children born to human immunodeficiency virus (HIV)-infected women are susceptible to undernutrition, but modifiable risk factors and the time course of the development of undernutrition have not been well characterized. The objective of this study was to identify maternal, socioeconomic and child characteristics that are associated with stunting, wasting and underweight among Tanzanian children born to HIV-infected mothers, followed from 6 weeks of age for 24 months. Maternal and socioeconomic characteristics were recorded during pregnancy, data pertaining to the infant's birth were collected immediately after delivery, morbidity histories and anthropometric measurements were performed monthly. Multivariate Cox proportional hazards methods were used to assess the association between potential predictors and the time to first episode of stunting, wasting and underweight. A total of 2387 infants (54.0% male) were enrolled and followed for a median duration of 21.2 months. The respective prevalence of prematurity (<37 weeks) and low birth weight (<2500 g) was 15.2% and 7.0%; 11.3% of infants were HIV-positive at 6 weeks. Median time to first episode of stunting, wasting and underweight was 8.7, 7.2 and 7.0 months, respectively. Low maternal education, few household possessions, low infant birth weight, child HIV infection and male sex were all independent predictors of stunting, wasting and underweight. In addition, preterm infants were more likely to become wasted and underweight, whereas those with a low Apgar score at birth were more likely to become stunted. Interventions to improve maternal education and nutritional status, reduce mother-to-child transmission of HIV, and increase birth weight may lower the risk of undernutrition among children born to HIV-infected women

Declining HIV-1 Prevalence and Incidence among Police Officers - A potential Cohort for HIV Vaccine Trials, in Dar es Salaam, Tanzania.

A safe effective and affordable HIV vaccine is the most cost effective way to prevent HIV infection worldwide. Current studies of HIV prevalence and incidence are needed to determine potentially suitable cohorts for vaccine studies. The prevalence and incidence of HIV-1 infection among the police in Dar es Salaam in 1996 were 13.8% and 19.6/1000 PYAR respectively. This study aimed at determining the current prevalence and incidence of HIV in a police cohort 10 years after a similar study was conducted. Police officers in Dar es Salaam, Tanzania were prospectively enrolled into the study from 2005 and followed-up in an incidence study three years later. HIV infection was determined by two sequential enzyme linked immunosorbent assays (ELISAs) in the prevalence study and discordant results between two ELISAs were resolved by a Western blot assay. Rapid HIV assays (SD Bioline and Determine) were used for the incidence study. A total of 1,240 police participated in the HIV prevalence study from August 2005 to November 2008. Of these, 1101 joined the study from August 2005-September 2007 and an additional 139 were recruited between October 2007 to November 2008 while conducting the incidence study. A total of 726 (70%) out of the 1043 eligible police participated in the incidence study.The overall HIV-1 prevalence was 65/1240 (5.2%). Females had a non-statistically significant higher prevalence of HIV infection compared to males 19/253, (7.5%) vs. 46/987 (4.7%) respectively (p = 0.07). The overall incidence of HIV-1 was 8.4 per 1000 PYAR (95% CI 4.68-14.03), and by gender was 8.8 and 6.9 per 1000 PYAR, among males and females respectively, (p = 0.82). The HIV prevalence and incidence among the studied police has declined over the past 10 years, and therefore this cohort is better suited for phase I/II HIV vaccine studies than for efficacy trials

Brownian Simulations and Uni-Directional Flux in Diffusion

Brownian dynamics simulations require the connection of a small discrete simulation volume to large baths that are maintained at fixed concentrations and voltages. The continuum baths are connected to the simulation through interfaces, located in the baths sufficiently far from the channel. Average boundary concentrations have to be maintained at their values in the baths by injecting and removing particles at the interfaces. The particles injected into the simulation volume represent a unidirectional diffusion flux, while the outgoing particles represent the unidirectional flux in the opposite direction. The classical diffusion equation defines net diffusion flux, but not unidirectional fluxes. The stochastic formulation of classical diffusion in terms of the Wiener process leads to a Wiener path integral, which can split the net flux into unidirectional fluxes. These unidirectional fluxes are infinite, though the net flux is finite and agrees with classical theory. We find that the infinite unidirectional flux is an artifact caused by replacing the Langevin dynamics with its Smoluchowski approximation, which is classical diffusion. The Smoluchowski approximation fails on time scales shorter than the relaxation time $1/\gamma$ of the Langevin equation. We find the unidirectional flux (source strength) needed to maintain average boundary concentrations in a manner consistent with the physics of Brownian particles. This unidirectional flux is proportional to the concentration and inversely proportional to $\sqrt{\Delta t}$ to leading order. We develop a BD simulation that maintains fixed average boundary concentrations in a manner consistent with the actual physics of the interface and without creating spurious boundary layers

Bacteria isolated from bloodstream infections at a tertiary hospital in Dar es Salaam, Tanzania - antimicrobial resistance of isolates

Objective. A bloodstream infection (BSI) is a life-threatening condition. We studied the causative agents of BSIs and antimicrobial susceptibility patterns of bacterial isolates at Muhimbili National Hospital (MNH) in Dar es Salaam, Tanzania. Methods. A retrospective analysis of blood culture results obtained at MNH from January 2005 to December 2009 was done. Blood culture isolates judged to be clinically significant and antimicrobial susceptibility results of the bacteria were included. The frequencies and proportions of bacteria isolated and antimicrobial susceptibility results were analysed and compared using Pearson’s chi-square test and Fisher’s exact test where applicable, or the Mann-Whitney U-test. Results. A total of 13 833 blood cultures were performed. Bacterial pathogens were detected in 1 855 (13.4%), Gram-positive bacteria (1 523; 82.1%) being significantly more prevalent than Gram-negative bacteria (332; 17.9%) (p=0.008). The most common bacterial pathogens isolated were coagulase-negative staphylococci (CoNS) (1 250; 67.4%), S. aureus (245; 13.2%), Escherichia coli (131; 7%) and Klebsiella spp. (130; 7.0%). All bacteria isolated showed high resistance to penicillin G (70.6%), tetracycline (63.8%), cefotaxime (62.5%) and ampicillin (62.3%). Moderate to high resistance was seen against chloramphenicol (45.2%), erythromycin (35.0%), ciprofloxacin (29.3%), co-trimoxazole (25.0%) and gentamicin (23.5%). Of S. aureus isolates, 23.3% were resistant to methicillin. Conclusions. CoNS accounted for two-thirds of the bacterial pathogens isolated. High-level resistance was seen to first-line and inexpensive antimicrobial agents. Routine screening for extended-spectrum beta-lactamase production and methicillin resistance among Gram-negative rods and S. aureus from blood cultures should be instituted to monitor spread of multidrug-resistant isolates