Influence of the age and sex of human hosts on the distribution of Escherichia coli ECOR groups and virulence traits

Microbiology ◽  
2005 ◽  
Vol 151 (1) ◽  
pp. 15-23 ◽  
Author(s):  
David M. Gordon ◽  
Steven E. Stern ◽  
Peter J. Collignon

Escherichia coli were isolated from the faeces of 266 individuals living in the Canberra region of Australia. The isolates were characterized for their ECOR group membership (A, B1, B2 or D) and for the presence of 29 virulence-associated traits. Overall, 19·5 % of the strains were members of group A, 12·4 % B1, 45·1 % B2 and 22·9 % D. The frequency with which strains belonging to the four ECOR groups were observed varied with the age and sex of the hosts from which they were isolated. In males, the probability of isolating A or D strains increased with host age, whilst the probability of detecting a group B2 strain declined. In females, the probability of recovering A or B2 strains increased with increasing host age and there was a concomitant decline in the likelihood of isolating B1 or D strains. Of the 29 virulence-associated traits examined, 24 were detected in more than one strain. The likelihood of detecting most traits varied with a strain's ECOR membership, with the exception of afa/draBC, astA, cvaC, eaeA, iss and iutA, for which there was no statistically significant evidence of an association with ECOR group. The frequency with which fimH, iha, eaeA, iroN, hlyD, iss, ompT and K1 were detected in a strain depended on the age or sex of the host from which the strain was isolated. In group B2 strains many of the virulence traits were non-randomly associated, with some co-occurring in a strain less often than expected by chance, whilst others were co-associated. In 17 cases, the extent to which two virulence traits were co-associated was found to depend on host sex and age. The results of this study suggest that the morphological, physiological and dietary differences that occur among human individuals of different sex or age may influence the distribution of E. coli genotypes.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Melissa C. MacKinnon ◽  
Scott A. McEwen ◽  
David L. Pearl ◽  
Outi Lyytikäinen ◽  
Gunnar Jacobsson ◽  
...  

Abstract Background Escherichia coli is the most common cause of bloodstream infections (BSIs) and mortality is an important aspect of burden of disease. Using a multinational population-based cohort of E. coli BSIs, our objectives were to evaluate 30-day case fatality risk and mortality rate, and determine factors associated with each. Methods During 2014–2018, we identified 30-day deaths from all incident E. coli BSIs from surveillance nationally in Finland, and regionally in Sweden (Skaraborg) and Canada (Calgary, Sherbrooke, western interior). We used a multivariable logistic regression model to estimate factors associated with 30-day case fatality risk. The explanatory variables considered for inclusion were year (2014–2018), region (five areas), age (< 70-years-old, ≥70-years-old), sex (female, male), third-generation cephalosporin (3GC) resistance (susceptible, resistant), and location of onset (community-onset, hospital-onset). The European Union 28-country 2018 population was used to directly age and sex standardize mortality rates. We used a multivariable Poisson model to estimate factors associated with mortality rate, and year, region, age and sex were considered for inclusion. Results From 38.7 million person-years of surveillance, we identified 2961 30-day deaths in 30,923 incident E. coli BSIs. The overall 30-day case fatality risk was 9.6% (2961/30923). Calgary, Skaraborg, and western interior had significantly increased odds of 30-day mortality compared to Finland. Hospital-onset and 3GC-resistant E. coli BSIs had significantly increased odds of mortality compared to community-onset and 3GC-susceptible. The significant association between age and odds of mortality varied with sex, and contrasts were used to interpret this interaction relationship. The overall standardized 30-day mortality rate was 8.5 deaths/100,000 person-years. Sherbrooke had a significantly lower 30-day mortality rate compared to Finland. Patients that were either ≥70-years-old or male both experienced significantly higher mortality rates than those < 70-years-old or female. Conclusions In our study populations, region, age, and sex were significantly associated with both 30-day case fatality risk and mortality rate. Additionally, 3GC resistance and location of onset were significantly associated with 30-day case fatality risk. Escherichia coli BSIs caused a considerable burden of disease from 30-day mortality. When analyzing population-based mortality data, it is important to explore mortality through two lenses, mortality rate and case fatality risk.


1952 ◽  
Vol 96 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Erwin Neter ◽  
Lee F. Bertram ◽  
Dorothy A. Zak ◽  
Miriam R. Murdock ◽  
Carl E. Arbesman

A study on hemagglutination and hemolysis by Escherichia coli O111 and O55 (rabbit) antisera and on hemagglutination and hemolysis inhibition by E. coli O111 and O55 antigens revealed the following facts. 1. Red blood cells of man, dog, rabbit, guinea pig, sheep, rat, and chicken adsorb E. coli O111 and O55 antigens and thus become specifically agglutinable by the homologous E. coli antisera. 2. The adsorption of these E. coli antigens is a function of the concentration of the antigen, the time (from 5 minutes to 2 hours) of treatment of the red blood cells with the antigen, and the concentration of the red blood cells used. 3. Red blood cells of man and sheep adsorb simultaneously both antigens, as indicated by the fact that both antisera give agglutination of all red blood cells. Complete agglutination does not occur when a mixture of red blood cells treated separately with the two antigens is added to one or the other of the two antisera. 4. Treatment of red blood cells of man with one of the antigens does not block the adsorption of the second antigen. Human cells treated with either or both antigens are still agglutinated by the homologous blood group (A, B, and Rh)-specific antibodies. 5. In the presence of guinea pig complement, E. coli O111 and O55 antisera produce hemolysis of modified human red blood cells in titers of the same order of magnitude as those giving hemagglutination and bacterial agglutination. The same antisera produce hemolysis of sheep cells treated with the identical antigens in titers exceeding by far those giving agglutination of modified human or sheep red blood cells. 6. Both sediment and supernate of a boiled E. coli suspension are capable of modifying red blood cells for E. coli hemagglutination; in contrast, the supernate obtained from an unboiled suspension and then heated does not modify red blood cells for hemagglutination, although it contains the antigen which can specifically adsorb E. coli antibodies, as shown by means of the hemagglutination and hemolysis inhibition tests. 7. Both the unheated and the boiled suspensions of E. coli O111 and O55 inhibit hemagglutination and hemolysis specifically. 8. Rabbit red blood cells modified by either E. coli O111 or 055 antigens, upon intravenous injection into rabbits, engender specific E. coli antibodies. The significance of the results is discussed.


1996 ◽  
Vol 117 (1) ◽  
pp. 203-211 ◽  
Author(s):  
M. Muñoz ◽  
M. Álvarez ◽  
I. Lanza ◽  
P. Cármenes

SummaryFaeces samples from diarrhoeic and non-diarrhoeic lambs and goat kids aged 1–45 days were examined for enteric pathogens.Cryptosporidium parvumwas detected in both diarrhoeic lambs (45%) and goat kids (42%) but not in non-diarrhoeic animals. F5+(K99+) and/or F41+Escherichia colistrains were isolated from 26% and 22% of the diarrhoeic lambs and goat kids, respectively, although these strains, which did not produce enterotoxins ST I or LT I, were found with similar frequencies in non-diarrhoeic animals. A F5−F41−ST I+E. colistrain was isolated from a diarrhoeic lamb (0·6%). VerotoxigenicE. coliwas isolated from both diarrhoeic and non-diarrhoeic lambs (4·1% and 8·2%, respectively) and there was no association between infection and diarrhoea. The prevalence of group A rotavirus infection in diarrhoeic lambs was very low (2·1%). Groups A and B rotaviruses were detected in three (8·1%) and five (13·5%) diarrhoeic goat kids from two single outbreaks. Group C rotaviruses were detected in four non-diarrhoeic goat kids. An association of diarrhoea and infection was demonstrated only for group B rotavirus.Clostridium perfringenswas isolated from 10·8% of the diarrhoeic goat kids but not from non-diarrhoeic goat kids or lambs.Salmonella arizonaewas isolated from a diarrhoeic goat kid (2·7%) and the clinical characteristics of the outbreaks where these two latter enteropathogens were found different from the rest. Picobirnaviruses were detected in a diarrhoeic lamb. No coronaviruses were detected using a bovine coronavirus ELISA. No evidence was found of synergistic effect between the agents studied. Enteric pathogens were not found in four (8·7%) and three (20%) outbreaks of diarrhoea in lambs and goat kids, respectively.


1978 ◽  
Vol 56 (6) ◽  
pp. 1247-1250 ◽  
Author(s):  
George Hanek ◽  
C. H. Fernando

One thousand and forty pumpkinseeds (Lepomis gibbosus (L.)) were collected from May 1970 through October 1972 from the Bay of Quinte, Ontario. Also, 1018 specimens of the same host were collected during the same sampling period from West Lake, Prince Edward County, Ontario.Data were collected on three groups of gill parasites, Monogenea (seven species), Copepoda (three species), and glochidia (one species). The data, treated synecologically, were analysed using a two-factor ANOVA and Duncan's multiple range test. The roles of season, habitat, host age, and sex on parasite load were analysed. Host sex was found to have no effect on the three groups of parasites. The abundance of parasites increased with host age (P < 0.001). A marked seasonal effect was noted for all three groups of parasites (P < 0.001), all three being most abundant during the summer period. A eutrophic habitat, West Lake, was found significantly more favourable (P < 0.001) for all three parasitic groups.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Susan Mosquito ◽  
Maria J. Pons ◽  
Maribel Riveros ◽  
Joaquim Ruiz ◽  
Theresa J. Ochoa

Conventionally, inEscherichia coli, phylogenetic groups A and B1 are associated with commensal strains while B2 and D are associated with extraintestinal strains. The aim of this study was to evaluate diarrheagenic (DEC) and commensalE. coliphylogeny and its association with antibiotic resistance and clinical characteristics of the diarrheal episode. Phylogenetic groups and antibiotic resistance of 369E. colistrains (commensal strains and DEC from children with or without diarrhea) isolated from Peruvian children <1 year of age were determined by a Clermont triplex PCR and Kirby-Bauer method, respectively. The distribution of the 369E. colistrains among the 4 phylogenetic groups was A (40%), D (31%), B1 (21%), and B2 (8%). DEC-control strains were more associated with group A while DEC-diarrhea strains were more associated with group D(P<0.05). There was a tendency(P=0.06)for higher proportion of persistent diarrhea (≥14 days) among severe groups (B2 and D) in comparison with nonsevere groups (A and B1). Strains belonging to group D presented significantly higher percentages of multidrug resistance than the rest of the groups(P>0.01). In summary, DEC-diarrhea strains were more associated with group D than strains from healthy controls.


Microbiology ◽  
2003 ◽  
Vol 149 (12) ◽  
pp. 3575-3586 ◽  
Author(s):  
David M. Gordon ◽  
Ann Cowling

Escherichia coli was isolated from more than 2300 non-domesticated vertebrate hosts living in Australia. E. coli was most prevalent in mammals, less prevalent in birds and uncommon in fish, frogs and reptiles. Mammals were unlikely to harbour E. coli if they lived in regions with a desert climate and less likely to have E. coli if they lived in the tropics than if they lived in semi-arid or temperate regions. In mammals, the likelihood of isolating E. coli from an individual depended on the diet of the host and E. coli was less prevalent in carnivores than in herbivores or omnivores. In both birds and mammals, the probability of isolating E. coli increased with the body mass of the host. Hosts living in close proximity to human habitation were more likely to harbour E. coli than hosts living away from people. The relative abundance of E. coli groups A, B1, B2 and D strains in mammals depended on climate, host diet and body mass. Group A strains were uncommon, but were isolated from both ectothermic and endothermic vertebrates. Group B1 strains could also be isolated from any vertebrate group, but were predominant in ectothermic vertebrates, birds and carnivorous mammals. Group B2 strains were unlikely to be isolated from ectotherms and were most abundant in omnivorous and herbivorous mammals. Group D strains were rare in ectotherms and uncommon in endotherms, but were equally abundant in birds and mammals. The results of this study suggest that, at the species level, the ecological niche of E. coli is mammals with hindgut modifications to enable microbial fermentation, or in the absence of a modified hindgut, E. coli can only establish a population in ‘large-bodied’ hosts. The non-random distribution of E. coli genotypes among the different host groups indicates that strains of the four E. coli groups may differ in their ecological niches and life-history characteristics.


2002 ◽  
Vol 92 (5) ◽  
pp. 375-384 ◽  
Author(s):  
S. Mears ◽  
F. Clark ◽  
M. Greenwood ◽  
K.S. Larsen

AbstractHost choice and fecundity are two factors that may contribute to the variation in flea counts observed when assessing the potential risk of flea-borne transmission of pathogens from rodents to humans. Using the black rat, Rattus rattus Linnaeus, as host the effects of age and sex on host choice and fecundity of the Oriental rat flea, Xenopsylla cheopis Rothschild, were examined experimentally at 25°C and 80% rh. During the first two days of emergence from cocoons, female fleas dominated the sex ratio by 4:1 but from the third day onwards this switched to a male-dominated sex ratio of 4:1. The sex of the flea did not influence their host-seeking behaviour. Newly emerged fleas of both sexes were not influenced by the rat‘s presence and at seven days old both sexes demonstrated similar levels of attraction toward the rat host. The sex of the rat did not affect flea host-seeking behaviour. There was a 50–70% decline in the initial number of adult fleas during the first week after their release onto a rat host, and this decline was greatest on juvenile rats. Flea fecundity was also significantly lower on juvenile rat hosts but no differences due to the sex of the rat were observed. This experimental study supports the hypothesis that differences in flea count due to host sex, reported in field surveys, result from sexual differences in host behaviour and not from discriminatory host-seeking behaviour by X. cheopis. Differences in flea count due to host age may be affected by differences in X. cheopis fecundity, which may itself be mediated by host behaviour such as grooming.


2013 ◽  
Vol 58 (2) ◽  
pp. 1146-1152 ◽  
Author(s):  
Jia Chang Cai ◽  
Rong Zhang ◽  
Yan Yan Hu ◽  
Hong Wei Zhou ◽  
Gong-Xiang Chen

ABSTRACTTwenty-two KPC-2-producingEscherichia coliisolates were obtained from three hospitals in Hangzhou, China, from 2007 to 2011. One isolate, with OmpC porin deficiency, exhibited high-level carbapenem resistance. Pulsed-field gel electrophoresis showed that few isolates were indistinguishable or closely related. Multilocus sequence typing indicated that sequence type 131 (ST131) was the predominant type (9 isolates, 40.9%), followed by ST648 (5 isolates), ST405 (2 isolates), ST38 (2 isolates), and 4 single STs, ST69, ST2003, ST2179, and ST744. Phylogenetic analysis indicated that 9 group B2 isolates belonged to ST131, and 5 of 11 group D isolates belonged to ST648. Only one group B1 isolate and one group A isolate were identified. A representative plasmid (pE1) was partially sequenced, and a 7,788-bp DNA fragment encoding Tn3transposase, Tn3resolvase, ISKpn8transposase, KPC-2, and ISKpn6-like transposase was obtained. TheblaKPC-2-surrounding sequence was amplified by a series of primers. The PCR results showed that 13 isolates were consistent with the genetic environment in pE1. It is the first report of rapid emergence of KPC-2-producingE. coliST131 in China. TheblaKPC-2gene of most isolates was located on a similar genetic structure.


2002 ◽  
Vol 70 (6) ◽  
pp. 2891-2898 ◽  
Author(s):  
Yukie Shibata ◽  
Yoshihisa Yamashita ◽  
Kazuhisa Ozaki ◽  
Yoshio Nakano ◽  
Toshihiko Koga

ABSTRACT Six genes (rgpA through rgpF) that were involved in assembling the rhamnose-glucose polysaccharide (RGP) in Streptococcus mutans were previously identified (Y. Yamashita, Y. Tsukioka, K. Tomihisa, Y. Nakano, and T. Koga, J. Bacteriol. 180:5803-5807, 1998). The group-specific antigens of Lancefield group A, C, and E streptococci and the polysaccharide antigen of Streptococcus sobrinus have the same rhamnan backbone as the RGP of S. mutans. Escherichia coli harboring plasmid pRGP1 containing all six rgp genes did not synthesize complete RGP. However, E. coli carrying a plasmid with all of the rgp genes except for rgpE synthesized the rhamnan backbone of RGP without glucose side chains, suggesting that in addition to rgpE, another gene is required for glucose side-chain formation. Synthesis of the rhamnan backbone in E. coli required the initiation of transfer of N-acetylglucosamine to a lipid carrier and the expression of the rgpC and rgpD genes encoding the putative ABC transporter specific for RGP. The similarities in RGP synthesis between E. coli and S. mutans suggest common pathways for rhamnan synthesis. Therefore, we evaluated the rhamnosyl polymerization process in E. coli by high-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the lipooligosaccharide (LOS). An E. coli transformant harboring rgpA produced the LOS modified by the addition of a single rhamnose residue. Furthermore, the rgpA, rgpB, and rgpF genes of pRGP1 were independently mutated by an internal deletion, and the LOS chemotypes of their transformants were examined. The transformant with an rgpA deletion showed the same LOS profile as E. coli without a plasmid. The transformant with an rgpB deletion showed the same LOS profile as E. coli harboring rgpA alone. The transformant with an rgpF deletion showed the LOS band with the most retarded migration. On the basis of these results, we speculated that RgpA, RgpB, and RgpF, in that order, function in rhamnan polymerization.


2012 ◽  
Vol 78 (12) ◽  
pp. 4083-4091 ◽  
Author(s):  
Lin T. Brandal ◽  
Camilla Sekse ◽  
Bjørn-Arne Lindstedt ◽  
Marianne Sunde ◽  
Inger Løbersli ◽  
...  

ABSTRACTA previous national survey ofEscherichia coliin Norwegian sheep detectedeae-positive (eae+)E. coliO26:H11 isolates in 16.3% (80/491) of the flocks. The purpose of the present study was to evaluate the human-pathogenic potential of these ovine isolates by comparing them withE. coliO26 isolates from humans infected in Norway. All humanE. coliO26 isolates studied carried theeaegene and shared flagellar type H11. Two-thirds of the sheep flocks and 95.1% of the patients harbored isolates containingarcAallele type 2 andespKand were classified as enterohemorrhagicE. coli(EHEC) (stxpositive) or EHEC-like (stxnegative). These isolates were further divided into group A (EspK2 positive), associated withstx2-EDL933andstcEO103, and group B (EspK1 positive), associated withstx1a. Although thestxgenes were more frequently present in isolates from patients (46.3%) than in those from sheep flocks (5%), more than half of the ovine isolates in the EHEC/EHEC-like group had multiple-locus variable number of tandem repeat analysis (MLVA) profiles that were identical to those seen instx-positive human O26:H11 isolates. This indicates that EHEC-like ovine isolates may be able to acquirestx-carrying bacteriophages and thereby have the possibility to cause serious illness in humans. The remaining one-third of the sheep flocks and two of the patients had isolates fulfilling the criteria for atypical enteropathogenicE. coli(aEPEC):arcAallele type 1 andespKnegative (group C). The majority of these ovine isolates showed MLVA profiles not previously seen inE. coliO26:H11 isolates from humans. However, according to their virulence gene profile, the aEPEC ovine isolates should be considered potentially pathogenic for humans. In conclusion, sheep are an important reservoir of human-pathogenicE. coliO26:H11 isolates in Norway.


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