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C F Marrs

Publications and source records attributed to C F Marrs.

At least 37 records · Page 2Linked to original sources
PubMed1997

Type-4 pili of Kingella denitrificans.

Kingella denitrificans possess type-4 pili, and the type strain, ATCC 33394, contains at least four complete copies of type-4 pilin-encoding genes. Previously reported hybridization patterns of K. denitrificans chromosomal DNA seen using a Neisseria gonorrhoeae pilin gene region probe, had been interpreted as representing possible partial, silent gene loci. This now appears to be due to cross-reaction to multiple copies of 18-bp inverted repeat structures. Data are presented on a variety of colony variants which have changed from a spreading-corroding (SC) phenotype to a nonspreading-noncorroding (N) phenotype. Interestingly, while the SC to N transition is most often associated with loss of piliation in other bacteria containing type-4 pili, many of the K. denitrificans N variants still produce pilin, and some still produce pili.

Bacterial Outer Membrane Proteins↗
PubMed1997

Discovery of disseminated J96-like strains of uropathogenic Escherichia coli O4:H5 containing genes for both PapG(J96) (class I) and PrsG(J96) (class III) Gal(alpha1-4)Gal-binding adhesins.

The pyelonephritis-associated adhesin gene papG of Escherichia coli occurs in three variants. Whereas the class II and class III variants are common among human urinary tract infection isolates, the class I allele, despite being the first cloned, has previously been found only in source strain J96. Five strains have been discovered from geographically diverse locales that, like J96, contain both the class I and class III papG alleles. One strain caused bacteremia, whereas 4 caused cystitis. Like J96, all 5 had group III capsule genes, expressed the H5 flagellar antigen and the F13 fimbrial antigen, and exhibited similar genomic patterns and virulence factor profiles. These findings demonstrate that the class I papG allele is not unique to J96 but is present in a group of extraintestinal isolates of E. coli O4:H5 that represent a disseminated virulent clonal group.

Adhesins, Escherichia coli↗
PubMed1997

Transmission of uropathogens between sex partners.

Epidemiologic evidence and several case reports suggest that Escherichia coli causing urinary tract infection (UTI) may be transmitted between sex partners. In order to test this hypothesis, urinary, vaginal, and fecal E. coli isolates from 19 women with UTI were compared with E. coli found in random initial voids from their most recent male sex partner. E. coli was isolated from 4 of 19 male sex partners. In each case, the E. coli isolated from the man was identical by pulsed-field gel electrophoresis and bacterial virulence profile to the urinary E. coli from his sex partner.

Adult↗
PubMed1997

Distribution of drb genes coding for Dr binding adhesins among uropathogenic and fecal Escherichia coli isolates and identification of new subtypes.

The Dr family of related adherence structures, some fimbriated and others afimbriated, bind to decay-accelerating factor molecules on human cells. Dr is associated with recurring urinary tract infection (UTI), but the distribution of Dr subtypes among uropathogenic Escherichia coli causing UTI among otherwise healthy women has yet to be described. A total of 787 UTI and fecal E. coli isolates from college women were screened for the presence of Dr sequences (drb). Fifteen percent of UTI strains were drb positive, compared to 5% of fecal strains. The adhesin (E gene) subtype of each drb-positive strain was determined by type-specific PCR followed by restriction enzyme analysis. Among 78 drb-positive strains, we found 14 (18%) afaE1, 1 (1.3%) afaE2, 1 (1.3%) afaE3, 9 (12%) draE, 9 (12%) draE-afaE3 hybrid, 1 (1.3%) daaE, 32 (41%) afaE5, 4 (5.1%) F131 E gene-like, and 7 untypeable strains. All untypeable E genes were cloned and sequenced, revealing four additional new classes of E genes, including two similar to the previously identified nonfimbrial E series. While a great range of diversity exists among the E genes, restriction fragment length polymorphism analysis demonstrated that all of these drb operons share a highly conserved gene structure. The most common subtype, afaE5, occurred three times as often among UTI than fecal strains. Over half of the drb-positive strains and 80% of those positive for afaE5 have the same virulence signature (positive for aer, kpsMT, ompT, and fim), suggesting an association of this profile with UTI pathogenesis.

Adhesins, Escherichia coli↗
PubMed1997

Identification of two minor subunits in the pilus of Haemophilus influenzae.

Haemophilus influenzae type b (Hib) organisms produce pili, which mediate attachment to human cells and are multimeric structures composed of a 24-kDa subunit called pilin or HifA. Although pili from other organisms contain additional proteins accessory to pilin, no structural components other than pilin have been identified in Hib pili. Previous analysis of a Hib pilus gene cluster, however, suggested that two genes, hifD and hifE, may encode additional pilus subunits. To determine if hifD and hifE encode pilus components, the genes were overexpressed in Escherichia coli and the resulting proteins were purified and used to raise polyclonal antisera. Antisera raised against C-terminal HifD and HifE fragments reacted with H. influenzae HifD and HifE proteins, respectively, on Western immunoblots. Western immunoblot analysis of immunoprecipitated Hib pili demonstrated that HifD and HifE copurified with pili. In enzyme-linked immunosorbent assays, antisera raised against a recombinant HifE protein that contained most of the mature protein reacted more to piliated Hib than to nonpiliated Hib or to a mutant containing a hifE gene insertion. Immunoelectron microscopy confirmed that the HifE antiserum bound to pili and demonstrated that the antiserum bound predominantly to the pilus tips. These data indicate that HifD and HifE are pilus subunits. Adherence inhibition studies demonstrated that the HifE antiserum completely blocked pilus-mediated hemagglutination, suggesting that HifE mediates pilus adherence.

Adhesins, Bacterial↗
PubMed1996

Identification of four complete type 4 pilin genes in a single Kingella denitrificans genome.

We have cloned and sequenced four complete type 4 pilin genes from the type strain (ATCC 33394) of Kingella denitrificans. Two of these pilin genes, kdpB and kdpD, are in tandem, oriented in the same direction, and encode pilins of only 50% amino acid identity. The kdpA and kdpC loci are separately located from the kdpB-kdpD locus and from each other. At the DNA level kdpA and kdpC are nearly identical to kdpB and encode pilin proteins that are identical to KdpB. Bands of multiple hybridization previously hypothesized to be due to partial silent pilin gene loci are now shown to be due to the presence of 18-bp repeat sequences (IR18) associated with the pilin gene coding regions. These IR18 sequences exist most often as inverted repeats separated by 8 bp. IR18 sequences are structurally similar to the repetitive extragenic palindromic sequences of Escherichia coli, although they have different DNA sequences. The IR18 sequences also demonstrate homology to the DNA uptake sequences of Neisseria gonorrhoeae and may serve a similar function for K. denitrificans.

Amino Acid Sequence↗
PubMed1996

Role of pili in Haemophilus influenzae adherence to, and internalization by, respiratory cells.

To determine the role of pili in mediating adherence of type b and nontypeable Haemophilus influenzae to several respiratory cell types, piliated bacteria, nonpiliated phase variants, and nonpiliated mutants possessing insertionally inactivated pilin genes were tested. Both piliated and nonpiliated strains adhered to HeLa cells, nasal epithelial cells, A549 cells (type II pneumocyte-like cells), and two types of tracheal epithelial cells. Nonpiliated organisms adhered better than piliated variants to cultured HEp-2 cells, whereas piliated organisms adhered better than nonpiliated variants to bronchial epithelial cells and to shed buccal epithelial cells. GM1, a pilus receptor analog, inhibited pilus- but not nonpilus-mediated adherence. Piliated and nonpiliated H. influenzae were equally internalized by A549 cells. Thus, pili mediate adherence to some, but not all, cells derived from human respiratory tissues; nonpilus mechanisms contribute to both adherence, and internalization, of both piliated and nonpiliated organisms.

Bacterial Adhesion↗
PubMed1995

Bacterial virulence characteristics of Escherichia coli isolates from first-time urinary tract infection.

The frequency of nine potential Escherichia coli urinary tract infection (UTI) virulence factors was investigated among 216 isolates from 208 women 18-40 years old with first-time UTI. Factors were afimbrial adhesions I-IV and F1845 pili (drb), aerobactin (aer), group II capsules (kpsMT), cytotoxic necrotizing factor 1 (cnf1), alpha-hemolysin (hly), outer membrane protease T (ompT), Pap and Prs pili (prf), S fimbriae (sfa), and type 1 pili (fim). Women were enrolled at two sites. Pairwise comparisons found 14 statistically significant associations between virulence genes after correcting for multiple comparisons. This is the first report of five associations: aer and drb, kpsMT and ompT, ompT and cnf1, ompT and sfa, and prf and ompT. As ompT is not closely linked genetically to kpsMT, cnf1, prf, or sfa, ompT may be functionally linked with one or more of these other virulence factors.

Adult↗
PubMed1995

Virulence characteristics of Escherichia coli causing first urinary tract infection predict risk of second infection.

Escherichia coli causes most urinary tract infections (UTIs) in ambulatory populations. Several bacterial virulence factors occur more frequently among urinary E. coli isolates than among fecal isolates, but none have been reported to predict risk of second UTIs. DNA hybridization was used to characterize the bacterial virulence profiles of urinary E. coli isolates from 174 women with first UTI and compared for risk of second UTI. Of the women, 28 (16%) had a culture-confirmed second UTI within 6 months of a negative test-of-cure. Three virulence factors were associated with a significantly lower risk of second UTI: cytotoxic necrotizing factor (relative risk [RR] = 0.0; 95% confidence interval [CI], 0.0, 0.42); hemolysin (RR, 0.10; 95% CI, 0.01, 0.69), and S fimbrial adhesin (RR, 0.25; 95% CI, 0.06, 1.00). Dr binding was associated with a 2-fold increased risk of second UTI (RR, 2.30; 95% CI, 1.23, 4.29). Half of all paired first and second UTI isolates from the same subject were apparently the same.

Adult↗
PubMed1994

Identification of hifD and hifE in the pilus gene cluster of Haemophilus influenzae type b strain Eagan.

Haemophilus influenzae produces surface structures called pili that promote adherence to human cells. Three genes encoding the major pilus structural component (pilin), chaperone, and usher proteins (designated hifA, -B, and -C, respectively) have been identified previously. In this study, transposon mutagenesis and DNA sequence analysis identified two open reading frames (ORFs) downstream of, and in the same orientation as, hifC. These genes have been designated hifD and hifE. Both genes have predicted C-terminal amino acid homology to HifA, and mutations in either gene resulted in the loss of morphologic and functional pili, indicating that hifD and hifE encode pilus structural components and are required for pilus expression. Another ORF, identified immediately downstream of hifE, has a predicted amino acid sequence that is 70% identical to an aminopeptidase of Escherichia coli called PepN, and a mutation within this ORF did not alter pilus expression. These data indicate that the pepN homolog is not required for pilus biogenesis and that one end of the pilus gene cluster has been defined.

Adhesins, Bacterial↗
PubMed1994

Identification of a gene essential for piliation in Haemophilus influenzae type b with homology to the pilus assembly platform genes of gram-negative bacteria.

Haemophilus influenzae type b (Hib) pili are complex filamentous surface structures consisting predominantly of pilin protein subunits. The gene encoding the major pilin protein subunit of Hib adherence pili has been cloned and its nucleotide sequence has been determined. In order to identify specific accessory genes involved in pilus expression and assembly, we constructed isogenic Hib mutants containing insertional chromosomal mutations in the DNA flanking the pilin structural gene. These mutants were screened for pilin production, pilus expression, and hemagglutination. Pili and pilin production were assessed by immunoassays with polyclonal antisera specific for pilin and pili of Hib strain Eagan. Hemagglutination was semiquantitatively evaluated in a microtiter plate assay. Six Hib mutants produced proteins immunoreactive with antipilin antiserum but no longer produced structures reactive with antipilus antiserum. In addition, the mutants were unable to agglutinate human erythrocytes. Nucleotide sequence analysis localized the insertion sites in the six mutants to 2.5-kb open reading frame upstream of the pilin structural gene and immediately downstream of an Hib pilin chaperone gene. The amino acid sequence encoded by this open reading frame has significant homology to members of the pilus assembly platform protein family, including FhaA of Bordetella pertussis, MrkC of Klebsiella pneumoniae, and the Escherichia coli assembly platform proteins FimD and PapC. This open reading frame, designated hifC, appears to represent a gene essential to Hib pilus biogenesis that has genetic and functional similarity to the pilus platform assembly genes of other gram-negative rods.

Amino Acid Sequence↗
PubMed1993

Sequence divergence in two tandemly located pilin genes of Eikenella corrodens.

Eikenella corrodens normally inhabits the human respiratory and gastrointestinal tracts but is frequently the cause of abscesses at various sites. Using the N-terminal portion of the Moraxella nonliquefaciens pilin gene as a hybridization probe, we cloned two tandemly located pilin genes of E. corrodens 31745, ecpC and ecpD, and expressed the two pilin genes separately in Escherichia coli. A comparison of the predicted amino acid sequences of E. corrodens 31745 EcpC and EcpD revealed considerable divergence between the sequences of these two pilins and even less similarity to EcpA and EcpB of E. corrodens type strain ATCC 23834. EcpC from E. corrodens 31745 displayed high degrees of homology to the pilins of Neisseria gonorrhoeae and Pseudomonas aeruginosa. EcpD from E. corrodens 31745 showed the highest homologies with the pilin of one of the three P. aeruginosa classes, whereas EcpA and EcpB of strain ATCC 23834 most closely resemble Moraxella bovis pilins. These findings raise interesting questions about potential genetic transfer between different bacterial species, as opposed to convergent evolution.

Amino Acid Sequence↗
PubMed1993

Paradoxical effect of pilus expression on binding of antibodies by Haemophilus influenzae.

Haemophilus influenzae type b (Hib) pili are surface proteins that are associated with the ability of Hib to attach to human epithelial cells. Like pilus expression of other bacteria, expression of Hib pili undergoes phase variation. We observed that Hib in the piliated phase (Hib p+) bound monoclonal antibodies directed against six conserved, surface-exposed, nonpilus Hib outer membrane epitopes to a greater extent than Hib in the nonpiliated phase (Hib p-). However, after extended incubation, p+ and p- cells bound these antibodies in a similar fashion. The differential in nonpilus antibody binding to p+ and p- Hib was not related to the presence of the type b capsule. In addition, Hib p+ organisms whose pilin gene was insertionally inactivated and did not produce pili and Hib in the nonpiliated phase bound the nonpilus Hib antibodies similarly. Hib p+ and p- organisms did not differ in their binding of anti-type b capsule antibody, and the binding was specific for the epitopes recognized by the antibodies. In complement-dependent bactericidal assays, the nonpilus antibodies killed Hib p+ more effectively than Hib p-. The increased binding to, and killing of, Hib p+ by a variety of nonpilus antibodies may be important for host defense against invasive Hib.

Animals↗
PubMed1993

Infection rates, disease frequency, pilin gene rearrangement, and pilin expression in calves inoculated with Moraxella bovis pilin-specific isogenic variants.

Pili have been implicated as virulence factors that result in increased infectivity of Moraxella bovis, the causative agent of infectious bovine keratoconjunctivitis (IBK). Healthy calves' eyes were inoculated with I- or Q-piliate or nonpiliate M bovis Epp63 to compare the pathogenicity of these isogenic variants. Pathogenicity was determined by the rate of persistent M bovis infection and the prevalence of clinical IBK. Inoculation with M bovis expressing the Q pili resulted in the highest frequency of infection and IBK, whereas I-piliate M bovis elicited a lower rate and nonpiliate M bovis did not result in infection. In vivo pilin gene rearrangement and pilin-type switching were evaluated by DNA hybridization and immunoblot. Gene rearrangement and type switching varied dependently, and were observed only in eyes inoculated with Q-piliate M bovis. This study suggests that Q pili are specific for colonization of bovine corneal epithelium, whereas I pili enable maintenance of an established infection.

Animals↗
PubMed1992

Vaccine errors.

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Haemophilus influenzae↗