Chlamydiae in febrile children with respiratory tract symptoms and age-matched controls, Ghana.

Members of the Chlamydiales order are obligate intracellular pathogens causing acute and chronic infectious diseases. Chlamydiaceae are established agents of community- and zoonotically acquired respiratory tract infections, and emerging pathogens among the Chlamydia-related bacteria have been implicated in airway infections. The role of both in airway infections in Africa is underexplored. We performed a case -control study on the prevalence of Chlamydiaceae and Chlamydia-related emerging pathogens in children with febrile respiratory tract infections in West Africa, Ghana. Using a pan-Chlamydiales broad-range real-time PCR, we detected chlamydial DNA in 11 (1.9%) of 572 hospitalized febrile children with respiratory tract symptoms and in 24 (4.3%) of 560 asymptomatic age-matched controls (p 0.03). Chlamydiaceae were found to be common among both symptomatic and healthy Ghanaian children, with Chlamydia pneumoniae being the most prevalent species. Parachlamydiaceae were detected in two children without symptoms but not in the symptomatic group. We identified neither Chlamydia psittaci nor Simkania negevensis but a member of a new chlamydial family that shared 90.2% sequence identity with the 16S rRNA gene of the zoonotic pathogen Chlamydia pecorum. In addition, we found a new Chlamydia-related species that belonged to a novel family sharing 91.3% 16S rRNA sequence identity with Candidatus Syngnamydia venezia. The prevalence and spectrum of chlamydial species differed from previous results obtained from children of other geographic regions and our study indicates that both, Chlamydiaceae and Chlamydia-related bacteria, are not clearly linked to clinical symptoms in Ghanaian children.

Resistance mechanisms of multiresistant Pseudomonas aeruginosa strains from Germany and correlation with hypermutation.

In this study, we analyzed the mechanisms of multiresistance for 22 clinical multiresistant and clonally different Pseudomonas aeruginosa strains from Germany. Twelve and 10 strains originated from cystic fibrosis (CF) and non-CF patients, respectively. Overproduction of the efflux systems MexAB-OprM, MexCD-OprJ, MexEF-OprN, and MexXY-OprM was studied. Furthermore, loss of OprD, alterations in type II topoisomerases, AmpC overproduction, and the presence of 25 acquired resistance determinants were investigated. The presence of a hypermutation phenotype was also taken into account. Besides modifications in GyrA (91%), the most frequent mechanisms of resistance were MexXY-OprM overproduction (82%), OprD loss (82%), and AmpC overproduction (73%). Clear differences between strains from CF and non-CF patients were found: numerous genes coding for aminoglycoside-modifying enzymes and located, partially in combination with beta-lactamase genes, in class 1 integrons were found only in strains from non-CF patients. Furthermore, multiple modifications in type II topoisomerases conferring high quinolone resistance levels and overexpression of MexAB-OprM were exclusively detected in multiresistant strains from non-CF patients. Correlations of the detected phenotypes and resistance mechanisms revealed a great impact of efflux pump overproduction on multiresistance in P. aeruginosa. Confirming previous studies, we found that additional, unknown chromosomally mediated resistance mechanisms remain to be determined. In our study, 11 out of 12 strains and 3 out of 10 strains from CF patients and non-CF patients, respectively, were hypermutable. This extremely high proportion of mutator strains should be taken into consideration for the treatment of multiresistant P. aeruginosa.

Evaluation of potential sources of proteins in diets for rainbow trout (Oncorhynchus mykiss).

7 diets were prepared containing as their only source of protein one of the following feeds: fish meal, casein, hydrolyzed feather meal, grieves, wheat gluten, maize gluten, soybean meal. Crystalline amino acids were supplemented except in cases of fish meal and casein to prevent specific amino acid deficiencies. Concentrations of N x 6.25 ranged between 436 and 457 g/kg dry matter (DM). Cr2O3 was added to each diet for indirect determination of digestibilities. Each diet was fed to triplicate groups of 20 rainbow trout of an average initial weight of 60 g. After 66 feeding days, all trout were killed and used for whole body analyses. Due to severely reduced intake, trout fed the casein based diet gained only about half as much weight as trout fed the fish meal based diet, though at the same fed conversion ratio of 1.0 kg gain per kg dietary DM. Gains on the other diets ranged between these two treatments with poorer feed conversion ratios. Digestibilities of crude protein of fish meal, casein, hydrolyzed feather meal, grieves, wheat gluten, maize gluten and soybean meal were: 86, 98, 67, 81, 97, 87, and 94%, respectively. The corresponding contents of digestible energy were: 21.2, 21.8, 15.4, 16.5, 19.6, 18.3, and 14.4 Mj/kg DM. Efficiency of utilization of digestible energy ranged between 43 and 54%, that of digestible crude protein between 32 and 41%.

Hydrolyzed feather meal as feed component in diets for rainbow trout (Oncorhynchus mykiss) and effects of dietary protein/energy ratio on the efficiency of utilization of digestible energy and protein.

Two feeding trials were performed on rainbow trout of mean initial weights of 40 and 50 g and lasting for 12 and 14 weeks, respectively. In trial 1, diets contained per kg 300 g fish meal and varying proportions of gelatinized maize starch plus either casein or hydrolyzed feather meal. Dietary crude protein content varied from about 27 to 53%. In trial 2, all diets had about 45% crude protein. Fish meal (300 g/kg) was replaced in 3 steps by hydrolyzed feather meal either without or with supplementation of L- lysine.HCl and/or DL-methionine. In trial 1, efficiency of utilization of digestible energy (DE) rose from 38 to 50% when the ratio digestible crude protein (DCP)/DE was increased from about 11 to 17 g/MJ irrespective of the source of additional DCP, but did not further increase at higher ratios DCP/DE. Efficiency of utilization of DCP was about 50% as long as the ratio DCP/DE did not exceed 17 g/MJ. With progressing replacement of fish meal by hydrolyzed feather meal, efficiencies of utilization of DE as well as of DCP were reduced, the respective rates of reduction being about halved by supplementing lysine with no effect of supplementing methionine.