BackgroundMultidrug resistant Pseudomonas aeruginosa and Acinetobacter baumannii are common causes of health care associated infections worldwide. Carbapenems are effective against infections caused by multidrug resistant Gram-negative bacteria including Pseudomonas and Acinetobacter species. However, their use is threatened by the emergence of carbapenemase-producing strains. The aim of this study was to determine the prevalence of carbapenem-resistant P. aeruginosa and A. baumannii at Mulago Hospital in Kampala Uganda, and to establish whether the hospital environment harbors carbapenem-resistant Gram-negative rods.ResultsBetween February 2007 and September 2009, a total of 869 clinical specimens were processed for culture and sensitivity testing yielding 42 (5 %) P. aeruginosa and 29 (3 %) A. baumannii isolates, of which 24 % (10/42) P. aeruginosa and 31 % (9/29) A. baumannii were carbapenem-resistant. Additionally, 80 samples from the hospital environment were randomly collected and similarly processed yielding 58 % (46/80) P. aeruginosa and 14 % (11/80) A. baumannii, of which 33 % (15/46) P. aeruginosa and 55 % (6/11) A. baumannii were carbapenem-resistant. The total number of isolates studied was 128. Carbapenemase genes detected were blaIMP-like (36 %, 9/25), blaVIM-like (32 %, 8/25), blaSPM-like (16 %, 4/25); blaNDM-1-like (4 %, 1/25) in carbapenem-resistant P. aeruginosa, and blaOXA-23-like (60 %, 9/15), blaOXA-24-like (7 %, 1/15), blaOXA-58-like (13 %, 2/15), and blaVIM-like (13 %, 2/15) in carbapenem-resistant A. baumannii. Furthermore, class 1 integrons were detected in 38 % (48/128) of P. aeruginosa and Acinetobacter, 37 % (26/71) of which were in clinical isolates and 39 % (22/57) in environment isolates. Gene cassettes were found in 25 % (12/48) of integron-positive isolates. These were aminoglycoside adenylyltransferase ant(4′)-IIb (3 isolates); trimethoprim-resistant dihydrofolate reductase dfrA (2 isolates); adenyltransferase aadAB (3 isolates); QacE delta1 multidrug exporter (2 isolates); quinolone resistance pentapeptide repeat protein qnr (1 isolate); and metallo-β-lactamase genes blaVIM-4-like, blaIMP-19-like, and blaIMP-26-like (1 isolate each). Gene cassettes were missing in 75 % (36/48) of the integron-positive isolates.ConclusionsThe prevalence of carbapenem-resistant P. aeruginosa and Acinetobacter among hospitalized patients at Mulago Hospital is low compared to rates from South-East Asia. However, it is high among isolates and in the environment, which is of concern given that the hospital environment is a potential source of infection for hospitalized patients and health care workers.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-2986-7) contains supplementary material, which is available to authorized users.

For conservation purposes and due to growing ecotourism, free-ranging mountain gorillas (Gorilla gorilla beringei) have been habituated to humans. Fecal specimens (n ϭ 62) collected in January 1999 from mountain gorillas of the Bwindi and Mgahinga National Parks, Uganda, were tested for Campylobacter spp., Salmonella spp., and Shigella spp., and the overall prevalence of infection was 19%, 13%, and 6%, respectively. The prevalence of positive specimens was not related to the year of habituation of a gorilla group to humans. Campylobacter spp., Salmonella, and Shigella spp. infections were not distributed equally among the age classes of gorillas; most of the enteropathogens (80%), and all Shigella spp. organisms, S. sonnei, S. boydii, and S. flexneri, were isolated from subadults and adult gorillas with ages ranging from 6.0 to 11.9 yr. The prevalence of Campylobacter spp. and Salmonella spp. infections among human-habituated gorillas has doubled during the last 4 yr, and isolation of Shigella spp. for the first time from mountain gorillas, may indicate enhanced anthropozoonotic transmission of these enteropathogens.

Brucellosis is a key zoonosis of major public health, animal welfare and economic significance, and is endemic in livestock in Uganda. A cross-sectional epidemiological study was carried out to estimate the sero-prevalence of brucellosis and identify factors associated with sero-positivity in cattle in urban and peri-urban Gulu and Soroti towns of Northern and Eastern Uganda, respectively. A total of 1007 sera and data on biologically plausible risk factors from 166 herds and their spatial locations, were collected from cattle reared in urban and peri-urban Gulu and Soroti towns of Uganda. The sera were analyzed using indirect ELISA and sero-positive reactors confirmed by competitive ELISA. Multivariable models were used to investigate for risk factors. The overall animal-level and herd-level sero-prevalence was 7.5% (76/1007, 95% Confidence Interval (CI): 6.15–9.4%) and 27.1% (45/166, 95% CI: 20.9–34.3%), respectively. Herd-level sero-prevalence was significantly (P<0.001) higher in Soroti than Gulu. In Gulu town, sero-positivity increased with an increase in herd size (P=0.03) and age (P=0.002), and was higher in cattle brought in from western Uganda (P<0.0001). In Soroti town, introduction of new cattle into a herd was significantly (P=0.027) associated with herd sero-positivity. There was a geographically differential risk (clustering) of Brucella sero- positivity in herds in Soroti, while sero-positivity was homogeneously distributed in Gulu. The data highlight brucellosis occurrence and major risk factors for its transmission in cattle in urban and peri-urban areas.

Sequencing and analysis of three discrete genome regions of African swine fever viruses (ASFV) from archival samples collected in 2007-2011 and active and passive surveillance between 2012 and 2015 in Nigeria were carried out. Analysis was conducted by genotyping of three single-copy African swine fever (ASF) genes. The E183L and B646L genes that encode structural proteins p54 and p72, respectively, were utilized to delineate genotypes before intragenotypic resolution by characterization of the tetrameric amino acid repeat region within the hypervariable central variable region of the B602L gene. The results showed no variation in the p72 and p54 gene regions sequenced. Phylogeny of p72 sequences revealed that all the Nigerian isolates belonged to genotype I, while that of the p54 recovered the Ia genotype. Analysis of B602L gene revealed the differences in the number of tetrameric repeats. Four new variants (Tet-15, Tet-17a, Tet-17b and Tet-48) were recovered, while a fifth variant (Tet-20) was the most widely distributed in the country displacing Tet-36 reported previously in 2003-2006. The viruses responsible for ASF outbreaks in Nigeria are from very closely related but mutated variants of the virus that have been circulating since 1997. A practical implication of the genetic variability of the Nigerian viral isolates in this study is the need for continuous sampling and analysis of circulating viruses, which will provide epidemiological information on the evolution of ASFV in the field versus new incursion for informed strategic control of the disease in the country.

In swine, the most common and severe enterotoxigenic Escherichia coli (ETEC) infections are caused by strains that express K88 (F4) ؉ fimbriae, heat-labile enterotoxin (LT), heat-stable enterotoxin b (STb), and enteroaggregative E. coli heat-stable toxin 1. Previous studies based on a design that involved enterotoxin genes cloned into a nontoxigenic fimbriated strain have suggested that LT but not STb plays an important role in dehydrating diarrheal disease in piglets <1 week old and also enhances bacterial colonization of the intestine. In the present study, we compared these two toxins in terms of importance for piglets >1 week old with a study design that involved construction of isogenic single-and double-deletion mutants and inoculation of 9-day-old F4ac receptor-positive gnotobiotic piglets. Based on the postinoculation percent weight change per h and serum bicarbonate concentrations, the virulence of the STb ؊ mutant (⌬estB) did not significantly differ from that of the parent. However, deletion of the LT genes (⌬eltAB) in the STb ؊ mutant resulted in a complete abrogation of weight loss, dehydration, and metabolic acidosis in inoculated pigs, and LT complementation restored the virulence of this strain. These results support the hypothesis that LT is a more significant contributor than STb to the virulence of F4 ؉ ETEC infections in young F4ac receptor-positive pigs less than 2 weeks old. However, in contrast to previous studies with gnotobiotic piglets, there was no evidence that the expression of LT enhanced the ability of the F4 ؉ ETEC strain to colonize the small intestine.