Alkane biodegradation in Pseudomonas aeruginosa strains isolated from a polluted zone: identification of alkB and alkB-related genes

Pseudomonas aeruginosa strains that grow on crude oil as the sole source of carbon and energy were isolated from an environment in Morocco polluted by petroleum refinery effluents. The twenty isolates grew on saturated alkanes from C12 to C22. Three of the isolates were also able to grow on low molecular weight C6 to C10 n-alkanes, but the other 17 strains were not. The strains were tested for alkB and a/kB-related genes encoding alkane-1-monooxygenase (alkane hydroxylase). Oligonucleotide primers specific for the alkB gene of strain P. putida (GPo1 ) and for the alkB1 and alkB2 genes of P. aeruginosa strain PAO1 allowed amplification from the P. aeruginosa isolates of fragments similar to alkB1 and alkB2 genes of strain PAO1. Only 3 strains carried an alkB gene very similar to that of strain GPo1, and these strains were the same ones that could utilise C6 to C10 n-alkanes.     

Infectious bronchitis virus S1 gene sequence comparison is a better predictor of challenge of immunity in chickens than serotyping by virus neutralization.

Five strains of infectious bronchitis virus isolated from commercial chickens from the state of Pennsylvania, USA during the years 1998 and 1999 were studied. The strains were selected for cross-challenge in specific pathogen free chickens and virus neutralization in chick embryos on the basis of partial S1 sequence amino acid identity values. The partial sequences analysed spanned the hypervariable amino terminus region of S1 from amino acid residues 48 to 219, based on the Beaudette strain. Using their S1 identity values, the strains represented a continuum of genetic, and thus antigenic, relationships. When compared with strain PA/5083/99, strain PA/Wolgemuth/98 had high sequence identity (96%) followed by PA/171/99 (85%), PA/5344/98 (70%) and PA/1220/98 (34%). The method of Archetti and Horsfall was used for calculating antigenic relatedness values of virus neutralization tests. The same formula was also applied to the percentage protection values of cross-challenge tests to derive protective relatedness values among the strains. The antigenic relatedness values, protective relatedness values, and the partial S1 sequence identity values were then analysed. The findings indicated partial S1 sequence identity values were more strongly correlated with protective relatedness values and than antigenic relatedness values.     

Phylogenetic-affiliation, antimicrobial potential and PKS gene sequence analysis of moderately halophilic Streptomyces sp. inhabiting an Indian saltpan

A Gram-positive, moderately halophilic Streptomyces strain, designated JAJ06, was isolated from saltpan soil collected at Tuticorin, India, and subjected to a polyphasic characterization with an insight into their biotechnological importance. Growth characteristics and antimicrobial com-pound producing capabilities of Streptomyces sp. JAJ06 were observed on various International Streptomyces Project (ISP) media and production media. Optimum growth was observed on modified ISP 4 medium supplemented with 4% NaCl (w/v) at 29 °C incubated for 7 days. Maximum antibacterial compound production with good mycelial growth was observed on starch-yeast extract-peptone medium prepared with seawater (90%, v/v). The 16S rRNA gene based phylogenetic affiliation was determined by using various bioinformatics tools and the strain was identified as Streptomyces sp. JAJ06 with 99% sequence similarity to Streptomyces radiopugnans(T) . An antimicrobial assay of antimicrobial compound derived from Streptomyces sp. JAJ06 against a set of bacteria and a yeast strain revealed antimicrobial activity with significant minimal inhibitory concentrations. The potential antimicrobial compound produced by Streptomyces sp. JAJ06 was found to be polyketide in nature. Cloning and sequence analysis of 613-bp fragment of ketosynthase gene from the type-II polyketide operon revealed that Streptomyces sp. JAJ06 has the KSα gene with 91% sequence similarity to the type II polyketide synthase gene of Streptomyces peucetius.     

Spike Gene Analysis of the DE072 Strain of Infectious Bronchitis Virus: Origin and Evolution

The entire S2 gene of the DE072 strain of infectious bronchitis virus (IBV) was sequenced. The nucleotide and amino acid sequence was most similar to the D1466 strain and was 84.8% and 89.9% identity, respectively. The nucleotide and amino acid sequence similarity among the DE072 strain and other IBV strains was less than 71.9% and 76.6%, respectively. Phylogenetic analysis, based on both nucleotide and amino acid sequence, showed that IBV isolates were divided into two distinct groups. The DE072 strain clustered only with the D1466 strain, and all of the other strains were distinct from those two viruses. Further the nucleotide sequence analysis of the entire spike glycoprotein gene of the DE072 strain demonstrated that most of the gene contained a D1466-like sequence, and five putative cross-over sites were identified. Based on cross-over site, phylogenetic trees were constructed for different regions of the spike gene, and a difference in topology between these trees was observed. Considering the difference in S2 gene sequence identity and tree topology, we assume that DE072 and D1466 viruses share a different origin from other isolates of IBV. Furthermore, entire spike gene analysis indicates that the DE072 strain has undergone recombination event as well as extensive antigenic variation.     

Cloning and characterization of a bifunctional glycosyl hydrolase from an antagonistic Pseudomonas putida strain P3(4)

A fluorescent pseudomonad strain P3(4) showing chitinolysis on chitinase detection agar and antagonism against Fusarium oxysporum f.sp dianthi causing vascular wilt of carnation was isolated from pea rhizosphere soil. PCR primers specific for glycosyl hydrolase family 5 (GH5) of Pseudomonas putida isolate KT2440 amplified a 947 bp fragment of the GH5 gene from P3(4). Cloning of this gene into Escherichia coli M15 using an expression vector pQE-30UA and screening on chitin and chitosan detection agar identified one positive clone (Pchi(+) ). Sequence analysis of the cloned insert revealed an open reading frame of 947 nucleotides corresponding to a protein of 315 amino acids with a predicted molecular mass of 38.0 kDa. The deduced amino acid sequence of the open reading frame (gene product/GH) showed 83-84% homology to the GH5 of P. putida strains F1 and KT2440, respectively. The purified enzyme was homogenous, as examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and was visualized as single fluorescent band in native gel assay with 4-methylumbelliferyl-N -acetyl-β;-D-glucosaminide and glycol chitosan, respectively. For hydrolysis of 4-nitrophenyl-N -acetyl-β;-D-glucosaminide (pNP-(GlcNAc) and colloidal chitosan, the enzyme had an optimal temperature of 40 °C, and was stable within the temperature range of 10 °C to 40 °C. The enzyme showed an optimal pH of 3.5, with maximum stabilities at 5.0 and 5.5 for hydrolysis of pNP-(GlcNAc) and colloidal chitosan, respectively. Fe(3+) and Cu(2+) stimulated chitinase and chitosanase activities by 74.2 and 51.4%, respectively. The purified GH displayed 70 and 45% inhibition of spore germination of the pathogenic fungi, Fusarium oxysporum f.sp. dianthi and Alternaria solani, respectively.     

Biodegradation of hydroxylated and methoxylated benzoic, phenylacetic and phenylpropenoic acids present in olive mill wastewaters by two bacterial strains

Two aerobic bacterial strains, a chlorophenol-degrading bacterium characterized in this work as a Ralstonia sp. LD35 on the basis of the sequence of the gene encoding for 16S ribosomal RNA, and Pseudomonas putida DSM 1868, capable of metabolizing 4-methoxybenzoic acid, were tested for their capacity to degrade monocyclic aromatic acids responsible for the toxicity of olive mill wastewaters (OMWs). Both strains possess interesting and complementary degradation capabilities in resting cell conditions: Ralstonia sp. LD35 was found to metabolize 4-hydroxybenzoic, 4-hydroxyphenylacetic, 3,4-dihydroxycinnamic and cinnamic acid, whereas DSM 1868 was capable of metabolizing 4-hydroxy-3-methoxybenzoic, 3,4-dimethoxybenzoic and 4-hydroxy-3,5-dimethoxybenzoic acid, as well as 4-hydroxybenzoic and 4-hydroxyphenylacetic acid. The kinetic parameters describing the growth of the two strains on the same compounds were determined in growing-cell batch conditions, and showed that both strains presented high affinity and high specific growth rates towards all assayed substrates. In addition, the two strains were capable of growing on and extensively biodegrading a mixture of monocyclic aromatic acids commonly found at high concentrations in OMWs, and of growing on a 20% dilution of a natural OMW. All these features make the two strains attractive candidates for the development of a biotechnological process for the biodegradation of aromatic compounds found in OMWs.     

Identification of Mycobacterium kansasii by using a DNA probe (AccuProbe) and molecular techniques

The newly formulated Mycobacterium kansasii AccuProbe was evaluated, and the results obtained with the new version were compared to the results obtained with the old version of this test by using 116 M. kansasii strains, 1 Mycobacterium gastri strain, and 19 strains of several mycobacterial species. The sensitivity of this new formulation was 97.4% and the specificity was 100%. Still, three M. kansasii strains were missed by this probe. To evaluate the variability within the species, genetic analyses of the hsp65 gene, the spacer sequence between the 16S and 23S rRNA genes, and the 16S rRNA gene of several M. kansasii AccuProbe-positive strains as well as all AccuProbe-negative strains were performed. Genetic analyses of the one M. gastri strain from the comparative assay and of two further M. gastri strains were included because of the identity of the 16S rRNA gene in M. gastri to that in M. kansasii. The data confirmed the genetic heterogeneity of M. kansasii. Furthermore, a subspecies with an unpublished hsp65 restriction pattern and spacer sequence was described. The genetic data indicate that all M. kansasii strains missed by the AccuProbe test belong to one subspecies, the newly described subspecies VI, as determined by the hsp65 restriction pattern and the spacer sequence. Since the M. kansasii strains that are missed are rare and all M. gastri strains are correctly negative, the new formulated AccuProbe provides a useful tool for the identification of M. kansasii.     

Genetic characterization of three novel chicken parvovirus strains based on analysis of their coding sequences

Chicken parvovirus (ChPV) is one of the causative agents of viral enteritis. Recently, the genome of the ABU-P1 strain of ChPV was fully sequenced and determined to have a distinct genomic composition compared with that of vertebrate parvoviruses. However, no comparative sequence analysis of coding regions of ChPVs was possible because of the lack of other sequence information. In this study, we obtained the nucleotide sequences of all genomic coding regions of three ChPVs by polymerase chain reaction using 13 primer sets, and deduced the amino acid sequences from the nucleotide sequences. The non-structural protein 1 (NS1) gene of the three ChPVs showed 95.0 to 95.5% nucleotide sequence identity and 96.5 to 98.1% amino acid sequence identity to those of NS1 from the ABU-P1 strain, respectively, and even higher nucleotide and amino acid similarities to one another. The viral proteins (VP) gene was more divergent between the three ChPV Korean strains and ABU-P1, with 88.1 to 88.3% nucleotide identity and 93.0% amino acid identity. Analysis of the putative tertiary structure of the ChPV VP2 protein showed that variable regions with less than 80% nucleotide similarity between the three Korean strains and ABU-P1 occurred in large loops of the VP2 protein believed to be involved in antigenicity, pathogenicity, and tissue tropism in other parvoviruses. Based on our analysis of full-length coding sequences, we discovered greater variation in ChPV strains than reported previously, especially in partial regions of the VP2 protein.     

Molecular characterization of G11P[25] and G3P[3] human rotavirus strains associated with asymptomatic infection in South India

Rotaviruses are the major etiological agents of diarrhea in children less than 5 years of age. Two unusual rotavirus strains not previously reported in India, G11P[25] (CRI 10795) and G3P[3] (CRI 33594) were isolated from faecal samples of asymptomatic children in India. The strains were characterized by sequence analysis of the genes encoding the VP7, VP4, VP6, and NSP4. The G11P[25] strain was closely related to the human G11P[25] strains from Bangladesh (with 98% identity at the nucleotide [nt] level and the amino acid [aa] level for the VP7 gene and 96% identity at the nt and 98% at the aa level for the VP4 gene). The G3P[3] strain was found to be related to a G3P[3] strain isolated in Thailand (CMH222; 88% identity at the nt level and 97% at aa level for the VP7 gene and 84% identity at the nt level and 90% at the aa level for the VP4 gene). Phylogenetic analysis of the VP6 and the NSP4 genes revealed that the Vellore G11P[25] strain was of VP6 subgroup II and NSP4 genotype B. The G3P[3] strain was identified as NSP4 genotype C and the VP6 gene showed 97% identity at the deduced amino acid level with strain CMH222 (Thailand) strain but did not cluster with sequences of SGI, SGII, SGI+II or SG-nonI/nonII. Both strains had gene segments of animal rotavirus origin suggesting inter-species transmission of rotavirus, and in the case of G11P[25] possibly underwent reassortment subsequently with human strains resulting in an animal-human hybrid strain.     

Enterococcus gilvus sp. nov. and Enterococcus pallens sp. nov. isolated from human clinical specimens

Light yellow-pigmented (strain PQ1) and yellow-pigmented (strain PQ2), gram-positive, non-spore-forming, nonmotile bacteria consisting of pairs or chains of cocci were isolated from the bile of a patient with cholecystitis (PQ1) and the peritoneal dialysate of another patient with peritonitis (PQ2). Morphologically and biochemically, the organisms phenotypically belonged to the genus Eterococcus. Whole-cell protein (WCP) analysis and sequence analysis of a segment of the 16S rRNA gene suggested that they are new species within the genus Enterococcus. PQ1 and PQ2 displayed less than 70% identities to other enterococcal species by WCP analysis. Sequence analysis showed that PQ1 shared the highest level of sequence similarity with Enterococcus raffinosus and E. malodoratus (sequence similarities of 99.8% to these two species). Sequence analysis of PQ2 showed that it had the highest degrees of sequence identity with the group I enterococci E. malodoratus (98.7%), E. raffinosus (98.6%), E. avium (98.6%), and E. pseudoavium (98.6%). PQ1 and PQ2 can be differentiated from the other Enterococcus spp. in groups II, III, IV, and V by their phenotypic characteristics: PQ1 and PQ2 produce acid from mannitol and sorbose and do not hydrolyze arginine, placing them in group I. The yellow pigmentation differentiates these strains from the other group I enterococci. PQ1 and PQ2 can be differentiated from each other since PQ1 does not produce acid from arabinose, whereas PQ2 does. Also, PQ1 is Enterococcus Accuprobe assay positive and pyrrolidonyl-beta-naphthylamide hydrolysis positive, whereas PQ2 is negative by these assays. The name Enterococcus gilvus sp. nov. is proposed for strain PQ1, and the name Enterococcus pallens sp. nov. is proposed for strain PQ2. Type strains have been deposited in culture collections as E. gilvus ATCC BAA-350 (CCUG 45553) and E. pallens ATCC BAA-351 (CCUG 45554).     

Molecular cloning of the fur gene from Actinobacillus actinomycetemcomitans

In several bacterial species, iron availability in host tissues is coordinated with the expression of virulence determinants through the fur gene product. Initial experiments showed that a cloned Escherichia coli fur gene probe hybridized to Southern blots of Actinobacillus actinomycetemcomitans strain JP2 (serotype b) chromosomal DNA. The A. actinomycetemcomitans fur gene was then cloned utilizing partial functional complementation of the fur mutant in E. coli strain H1780. Analysis of the cloned DNA sequence revealed a 438-bp open reading frame with a deduced 146-amino-acid sequence exhibiting 80% identity to Haemophilus influenzae Fur and 62% identity to E. coli Fur. The pUC Aafur gene probe (generated from JP2 serotype b) hybridized to representatives from all five A. actinomycetemcomitans serotypes as well as to two strains derived from monkeys, suggesting that fur is widely distributed in A. actinomycetemcomitans. Open reading frames having >70% identity with the E. coli and H. influenzae flavodoxin and gyrase A genes, respectively, were found. Expression of the A. actinomycetemcomitans fur gene product repressed fiu expression and siderophore production in E. coli. A gel shift assay demonstrated that the expressed A. actinomycetemcomitans Fur protein bound the bacterial fur consensus sequence. Further characterization of the fur gene product in A. actinomycetemcomitans may improve our understanding of its role in the pathogenesis of periodontal disease and may lead to specific therapeutic modalities.     

Nucleotide sequence variation of the VP7 gene of two G3-type rotaviruses isolated from dogs

The sequence of the VP7 gene of two rotaviruses isolated from dogs in southern Italy was determined and the inferred amino acid sequence was compared with that of other rotavirus strains. There was very high nucleotide and amino acid identity between canine strain RV198/95 and other canine strains, and to the human strain HCR3A. Strain RV52/96, however, was found to have about 95% identity to the G3 serotype canine strains K9, A79-10 and CU-1 and 96% identity to strain RV198/95 and to the simian strain RRV. Therefore both of the canine strains belong to the G3 serotype. Nevertheless, detailed analysis of the VP7 variable regions revealed that RV52/96 possesses amino acid substitutions uncommon to the other canine isolates. In addition, strain RV52/96 exhibited a nucleotide divergence greater than 16% from all the other canine strains studied; however, it revealed the closest identity (90.4%) to the simian strain RRV. With only a few exceptions, phylogenetic analysis allowed clear differentiation of the G3 rotaviruses on the basis of the species of origin. The nucleotide and amino acid variations observed in strain RV52/96 could account for the existence of a canine rotavirus G3 sub-type.     

2008年甘肃省新分离乙脑病毒的分子生物学特征

目的 对2008年甘肃省新分离乙脑病毒的PrM和E基因区段进行序列测定和分析,明确新分离病毒的基因型别并对E基因序列的分子特征进行分析.方法 对新分离乙脑病毒的PrM和E基因区段进行PCR扩增并测定序列.使用ClustalX2.09、MegAlign和Mega4软件对核苷酸和氨基酸序列进行分析并绘制系统发生树.结果 系统进化分析结果显示6株病毒均为基因Ⅰ型乙脑病毒,并且与2001和2002年越南分离株、2004年日本分离株及2004年我国四川省分离株进化关系较近.新分离株与减毒活疫苗株SA14-14-2相比,E基因核苷酸同源性为87.5%～87.9%,氨基酸同源性为96.8%～97.2%.新分离株与疫苗株在E基因区段存在11处共同位点的氨基酸差异.结论 2008年甘肃省分离的乙脑病毒均为基因Ⅰ型乙脑病毒,新分离株E基因氨基酸序列与疫苗株相比有部分差异,但均不属于决定抗原性的关键位点.     

标准菌株和临床菌株oipA基因的检测及其核苷酸序列比对

目的：检测幽门螺杆菌标准菌株NCTC11637及临床分离菌株Hp1和Hp2的oipA基因,分析其核苷酸序列,比对其与国际标准菌株Hp 26695的同源性.方法：常规方法培养幽门螺杆菌,提取DNA,PCR法扩增oipA基因,检测其核苷酸序列,并比较其与Hp 26695的同源性.结果：NCTC11637及Hp1、Hp2均表达oipA基因.其核苷酸序列与Hp 26695比对,NCTC11637有48个突变位点、Hp1有48个突变位点、Hp2有50个突变位点,同源性均为94%.NCTC11637与Hp1的同源性为100%、与Hp2的同源性为97%.结论：NCTC11637、Hp1、Hp2均表达oipA基因,但不同菌株oipA基因的核苷酸序列有所不同.     

Biofilm formation by Escherichia coli is stimulated by synergistic interactions and co-adhesion mechanisms with adherence-proficient bacteria

Laboratory strains of Escherichia coli do not show significant ability to attach to solid surfaces and to form biofilms. We compared the adhesion properties of the E. coli PHL565 laboratory strain to eight environmental E. coli isolates: only four isolates displayed adhesion properties to glass significantly higher than PHL565. The ability of the adhesion-proficient isolates to attach to glass tubes strongly correlated with their ability to express curli (thin aggregative fimbriae), thus suggesting that curli are a common adhesion determinant in environmental strains. Despite its inability to attach to solid surfaces, growth of E. coli PHL565 in mixed cultures with Pseudomonas putida MT2 resulted in co-adhesion and in formation of a mixed E. coli/P. putida biofilm, which was able to colonize glass surfaces with dramatic efficiency compared to P. putida alone. E. coli/P. putida interactions stimulate initial adhesion to glass, and the presence of both bacterial species in the mature biofilm was confirmed by quantitative PCR. In contrast, no synergistic biofilm formation was observed in mixed cultures of E. coli with the Gram-positive bacterium Staphylococcus epidermidis. Interestingly, E. coli PHL565 also stimulated biofilm formation by bacterial communities isolated from drinking water distribution systems. Our results strongly suggest that co-adhesion and synergistic interaction with biofilm-forming species might represent an important mechanism, and a possible alternative strategy to production of adhesion determinants, for persistence and propagation of E. coli in the environment.     

Genetic variation in the dimorphic regions of rap-1 genes and rap-1 loci of Babesia bigemina

The rhoptry-associated protein-1 (RAP-1) of Babesia bigemina induces protective immune responses in cattle. RAP-1 has two regions of sequence dimorphism at the carboxy and amino terminal ends, respectively. Neutralization-sensitive, surface-exposed B-cell epitopes are present in the amino terminal variant type 1 (NT-1), and CD4⁺ T-cell epitopes in the carboxy terminal variant type 1 (CT-1). Importantly, antibodies recognizing NT-1 epitopes do not cross react with NT-2 and CD4⁺ T-cells recognizing epitopes in CT-1 do not cross react with CT-2, suggesting that variation in dimorphic regions of RAP-1 is immunologically significant. We evaluated rap-1 locus structure and the extent of sequence variation in the dimorphic regions of rap-1 genes from geographically diverse strains of B. bigemina. All strains contained NT-1 and NT-2 the encoding sequences were highly conserved, with at least 99% nucleotide identity among strains. However, the Puerto Rico strain encoded a hybrid NT-1/NT-2 sequence which appears to have originated by a gene conversion event. The 3′ ends of rap-1 genes, which include the carboxy terminal variants, are conserved among strains. A new and conserved CT variant (CT-3), with a region of sequence identity to CT-2 and a sequence not related to either CT-1 or CT-2, was identified in all strains of B. bigemina. All but one strain encode both NTs and the three CT variants. The S1A strain, an attenuated strain from Argentina, does not encode CT-2. While NT-1 is associated only with CT-1, NT-2 can be associated with all three CT variants in RAP-1. Within the genome, rap-1 genes are arranged in tandem repeats but with different gene copy number and arrangements among strains. Collectively, the data suggest that gene conversion and unequal recombination events contribute to overall rap-1 sequence conservation among gene variants and strains but may also generate new rap-1 variants.     

Emergence of a unique penicillin-resistant Streptococcus pneumoniae serogroup 35 strain

We analyzed seven Streptococcus pneumoniae serogroup 35 isolates by pulsed-field gel electrophoresis of the genome and pbp2b gene nucleotide sequences. Three penicillin-susceptible strains and one penicillin-intermediate-resistant strain exhibited 100% identity to prototype R6. Two resistant strains and one other intermediate strain differed from them and contained a unique sequence.     

Genome characteristics of facultatively symbiotic Frankia sp. strains reflect host range and host plant biogeography

Soil bacteria that also form mutualistic symbioses in plants encounter two major levels of selection. One occurs during adaptation to and survival in soil, and the other occurs in concert with host plant speciation and adaptation. Actinobacteria from the genus Frankia are facultative symbionts that form N₂-fixing root nodules on diverse and globally distributed angiosperms in the “actinorhizal” symbioses. Three closely related clades of Frankia sp. strains are recognized; members of each clade infect a subset of plants from among eight angiosperm families. We sequenced the genomes from three strains; their sizes varied from 5.43 Mbp for a narrow host range strain (Frankia sp. strain HFPCcI3) to 7.50 Mbp for a medium host range strain (Frankia alni strain ACN14a) to 9.04 Mbp for a broad host range strain (Frankia sp. strain EAN1pec.) This size divergence is the largest yet reported for such closely related soil bacteria (97.8%–98.9% identity of 16S rRNA genes). The extent of gene deletion, duplication, and acquisition is in concert with the biogeographic history of the symbioses and host plant speciation. Host plant isolation favored genome contraction, whereas host plant diversification favored genome expansion. The results support the idea that major genome expansions as well as reductions can occur in facultative symbiotic soil bacteria as they respond to new environments in the context of their symbioses.     

Epidemiological study of pap genes among diarrheagenic or septicemic Escherichia coli strains producing CS31A and F17 adhesins and characterization of Pap(31A) fimbriae

The association of the pap operon with the CS31A and F17 adhesins was studied with 255 Escherichia coli strains isolated from calves, lambs, or humans with diarrhea. The three classes of PapG adhesin with different receptor binding preferences were also screened. The pap operon was associated with 50 and 36% of human strains that produced CS31A and ovine strains that produced F17, respectively. Among the bovine isolates, the pap operon was detected in 61% of the CS31A-positive isolates and 72% of the strains that produce both CS31A and F17. The class II adhesin gene was present in bovine (20%) and ovine (71%) isolates. Both class II and III adhesins were genetically associated with 36% of the human strains. The highest prevalence of the pap operon was observed among E. coli strains that produce additional adhesins involved in the binding of bacteria to intestinal cells. Among the bovine isolates, the reference strain for CS31A and F17c was found to be positive for the pap operon. Phenotypic and genotypic characterizations were undertaken. Pap(31A) appeared as fine and flexible fimbriae surrounding the bacteria but did not mediate adhesion to calf intestinal villi. Pap(31A) production was optimal with bacteria cultured on minimal growth media and repressed by addition of exogenous leucine. The deduced amino acid sequence of the PapA(31A) structural subunit showed 57 to 97% identity with the different P-related structural subunits produced by E. coli strains isolated from pigs with septicemia or humans with urinary tract infections. None of the three papG allelic variants was detected, but a homologous papG gene was present in the chromosome of strain 31A.