11 research outputs found
A comparative study of Multiple versus Single infection doses of Schistosoma haematobium in Golden hamsters ( Mesocricetus auratus )
Schistosoma haematobium is widely distributed in Africa. In Kenya,
endemic areas include the upper and the lower regions of the Coast
Province, Lake Victoria and the Kano plains. Low infection rates over
prolonged periods of time characterize schistosome infections of people
living in endemic areas. However, the common laboratory practice is to
expose the definitive host to a single high dose. In order to utilize
the laboratory results appropriately, it is important to know whether
or not a large single infection has similar results to multiple small
doses. In this study, immune responses, worm burden, gross and
histopathological patterns of multiple infection of S. haematobiumium
in the Golden hamster ( Mesocricetus auratus ) were compared with
those of single exposure. Multiple infections with low doses of the
parasite did not seem to be protective, as suggested by; more worms,
worse gross and histopathology in multiple low dose group compared to
single high dose group. Most probably there is an antigenic threshold,
which needs to be attained before protective mechanisms come into play.
Although necessary for protection, there was no direct correlation
between IgG levels and degree of protection
Antimicrobial resistance and plasmid profiles of Aeromonas hydrophila isolated from River Njoro, Kenya
The purpose of this study was to investigate the presence of Aeromonas hydrophila at commonly used water collection points on the River Njoro and to determine the in-vitro antimicrobial susceptibility and plasmid profiles of isolates. In total, 126 samples were collected and 36.5% of them were positive for A. hydrophila. The A. hydrophila were recovered on membrane filters, cultured on Trypticase Soy agar, Bile aesculin agar and Aeromonas Medium agar. They were further characterized using cytochrome oxidase and API 20E tests. Detection of drug susceptibility was determined using modified disc diffusion method to ampicillin (25 ìg), cefaclor (30 ìg), ceftizoxime (30 ìg), cefixime (5 ìg), cefazidime (30 ìg), gentamicin (200 ìg), streptomycin (25 ìg), chloramphenicol (50 ìg), nalidixic acid (30 ìg) and ciprofloxacin (1 ìg). Most of the isolates showed multi-drug resistance to two or more antibiotics. Chloramphenicol, nalidixic acid, ciprofloxacin, cefazidime and cefixime were the most sensitive drugs with 100% efficacy whereas ampicillin, cefaclor and streptomycin were the most resistant drugs having 100, 67 and 50 resistance, respectively. There was low resistance against ceftizoxime (16.7%) and gentamicin (23.3%). These results indicates that all A. hydrophila isolated from River Njoro had complete resistance to ampicillin and showed variable resistance to cefaclor, streptomycin, gentamycin and ceftizoxime. R-plasmids were extracted from multi-drug resistance strains and separated by agarose gel (0.8%) electrophoresis for profiling. Plasmid profiling revealed that most of the multi-drug resistant isolates contained one plasmid of 21.0 kb. Although some strains exhibited different antimicrobial resistance patterns, all of their plasmids were of the same size (21.0 kb). However, there were no plasmids in the antimicrobial sensitive isolates. This study also indicates that plasmid 21.0 kb is common in A. hydrophila and is important for antimicrobial resistance and virulence. Further studies are required to ascertain the role of this plasmid as a virulence marker.Key words: Aeromonas hydrophila, antimicrobial resistance, plasmid profile
Influence of Age of Mice on the Susceptibility to Murine Schistosomiasis Infection
Intensity of human schistosomiasis infection increases with age, a peak
being attained at early puberty. Hormones could be involved in the
age-related changes in susceptibility to schistosomiasis. Male BALB/c
mice were infected with Schistosoma mansoni either before or after
puberty and worm numbers, cellular immune responses, hormonal levels
and pathology analysed. Pre-puberty infected mice had a significantly
higher number of adult worms (p<0.05), more severe granulomas,
higher mortality rate and higher proliferative responses as compared to
postpuberty infected mice. Levels of the hormones were lower in the
pre-puberty infected mice as compared to the post-puberty group early
in the infection. Plasma levels of testosterone and luteinizing
hormones decreased significantly (p<0.05) in infected mice when
compared to controls. Susceptibility to S. mansoni in male BALB/c mice
seems to be influenced by levels of testosterone and leutenizing
hormone at infection. Albeit, an infection with S. mansoni seems to
lower the hormonal levels
Antimicrobial resistance and plasmid profiles of Aeromonas hydrophila isolated from River Njoro, Kenya
The purpose of this study was to investigate the presence of Aeromonas hydrophila at commonly used water collection points on the River Njoro and to determine the in-vitro antimicrobial susceptibility and plasmid profiles of isolates. In total, 126 samples were collected and 36.5% of them were positive for A. hydrophila. The A. hydrophila were recovered on membrane filters, cultured on Trypticase Soy agar, Bile aesculin agar and Aeromonas Medium agar. They were further characterized using cytochrome oxidase and API 20E tests. Detection of drug susceptibility was determined using modified disc diffusion method to ampicillin (25 μg), cefaclor (30 μg), ceftizoxime (30 μg), cefixime (5 μg), cefazidime (30 μg), gentamicin (200 μg), streptomycin (25 μg), chloramphenicol (50 μg), nalidixic acid (30 μg) and ciprofloxacin (1 μg). Most of the isolates showed multi-drug resistance to two or more antibiotics. Chloramphenicol, nalidixic acid, ciprofloxacin, cefazidime and cefixime were the most sensitive drugs with 100% efficacy whereas ampicillin, cefaclor and streptomycin were the most resistant drugs having 100, 67 and 50 resistance, respectively. There was low resistance against ceftizoxime (16.7%) and gentamicin (23.3%). These results indicates that all A. hydrophila isolated from River Njoro had complete resistance to ampicillin and showed variable resistance to cefaclor, streptomycin, gentamycin and ceftizoxime. R-plasmids were extracted from multi-drug resistance strains and separated by agarose gel (0.8%) electrophoresis for profiling. Plasmid profiling revealed that most of the multi-drug resistant isolates contained one plasmid of 21.0 kb. Although some strains exhibited different antimicrobial resistance patterns, all of their plasmids were of the same size (21.0 kb). However, there were no plasmids in the antimicrobial sensitive isolates. This study also indicates that plasmid 21.0 kb is common in A. hydrophila and is important for antimicrobial resistance and virulence. Further studies are required to ascertain the role of this plasmid as a virulence marker
A Comprehensive Genetic Analysis of Candidate Genes Regulating Response to Trypanosoma congolense Infection in Mice
About one-third of cattle in sub-Saharan Africa are at risk of contracting “Nagana”—a disease caused by Trypanosoma parasites similar to those that cause human “Sleeping Sickness.” Laboratory mice can also be infected by trypanosomes, and different mouse breeds show varying levels of susceptibility to infection, similar to what is seen between different breeds of cattle. Survival time after infection is controlled by the underlying genetics of the mouse breed, and previous studies have localised three genomic regions that regulate this trait. These three “Quantitative Trait Loci” (QTL), which have been called Tir1, Tir2 and Tir3 (for Trypanosoma Infection Response 1–3) are well defined, but nevertheless still contain over one thousand genes, any number of which may be influencing survival. This study has aimed to identify the specific differences associated with genes that are controlling mouse survival after T. congolense infection. We have applied a series of analyses to existing datasets, and combined them with novel sequencing, and other genetic data to create short lists of genes that share polymorphisms across susceptible mouse breeds, including two promising “candidate genes”: Pram1 at Tir1 and Cd244 at Tir3. These genes can now be tested to confirm their effect on response to trypanosome infection
Isolation and biochemical characterization of transferrin from the tsetse fly, Glossina morsitan centralis
No Abstract. The Egyptian Journal of Biochemistry and Molecular Biology Vol. 23(2) 2005: 169-18
A comparative study of Multiple versus Single infection doses of Schistosoma haematobium in Golden hamsters ( Mesocricetus auratus )
Schistosoma haematobium is widely distributed in Africa. In Kenya,
endemic areas include the upper and the lower regions of the Coast
Province, Lake Victoria and the Kano plains. Low infection rates over
prolonged periods of time characterize schistosome infections of people
living in endemic areas. However, the common laboratory practice is to
expose the definitive host to a single high dose. In order to utilize
the laboratory results appropriately, it is important to know whether
or not a large single infection has similar results to multiple small
doses. In this study, immune responses, worm burden, gross and
histopathological patterns of multiple infection of S. haematobiumium
in the Golden hamster ( Mesocricetus auratus ) were compared with
those of single exposure. Multiple infections with low doses of the
parasite did not seem to be protective, as suggested by; more worms,
worse gross and histopathology in multiple low dose group compared to
single high dose group. Most probably there is an antigenic threshold,
which needs to be attained before protective mechanisms come into play.
Although necessary for protection, there was no direct correlation
between IgG levels and degree of protection