National survey of Escherichia coli causing extraintestinal infections reveals the spread of drug-resistant clonal groups O25b:H4-B2-ST131, O15:H1-D-ST393 and CGA-D-ST69 with high virulence gene content in Spain.

OBJECTIVES: To evaluate the current prevalence of the three clonal groups O25b:H4-B2-ST131, O15:H1-D-ST393 and CGA-D-ST69 (where ST stands for sequence type) among Escherichia coli isolates causing extraintestinal infections in Spain and to characterize their virulence background, 500 consecutive non-duplicate E. coli isolates causing extraintestinal infections were analysed. METHODS: The 500 isolates were collected during February 2009 from five hospitals in different Spanish regions. Phylogenetic groups, STs, serotypes, virulence genes, PFGE profiles, antimicrobial resistance and extended-spectrum ß-lactamase (ESBL) enzymes were determined. RESULTS: The three clonal groups accounted for 19% of the 500 isolates. Furthermore, they accounted for 37% of the isolates exhibiting trimethoprim/sulfamethoxazole plus ciprofloxacin resistance, 34% of aminoglycoside-resistant isolates and 30% of multidrug-resistant isolates. Clonal group ST131 was the most prevalent, and accounted for 12% of isolates overall and for 23% of multidrug-resistant isolates. The ST131 isolates exhibited a significantly higher virulence score (mean of virulence genes 8.1) compared with the ST393 (6.0) and ST69 (5.4) isolates. The prevalence of ESBL-producing isolates was 7%. Six (10%) of the 59 ST131 isolates were positive for CTX-M-15 and one (6%) of the 16 ST393 isolates was positive for CTX-M-14, whereas none of the 22 ST69 isolates produced ESBL enzymes. CONCLUSIONS: The three clonal groups investigated accounted for 30% of the multidrug-resistant isolates, which gives evidence of an important clonal component in the emergence of resistances among extraintestinal pathogenic E. coli. Notably, a single high virulence clonal group (O25b:H4-B2-ST131) causes approximately 1 in every 10 extraintestinal infections in Spain, representing an important public health threat. A new variant of the ST131 clonal group, which is non-ESBL-producing but trimethoprim/sulfamethoxazole resistant and with high virulence content, is reported.

[Microbiological diagnosis of central nervous system infections]. / Diagnóstico microbiológico de las infecciones del sistema nervioso central.

The infections of the central nervous system are associated with high morbidity and mortality. Several agents including bacteria, viruses, fungi and protozoa can invade the CNS. They are different clinical presentations of these infections: meningitis, encephalitis, brain and epidural abscesses and cerebrospinal fluid shunt infections. The clinical course could be acute, subacute or chronic depending on the infecting agent and the location of the infection. The travelling entails a risk of infection by exotic agents of meningo-encephalitis such as robovirus and arbovirus, which require new diagnostic and therapeutic methods. Despite some progress in the treatment of the CNS infections, the mortality is usually high. Rapid diagnosis and emergent interventions are necessary to improve the outcome of those patients, and early and targeted antimicrobial treatment and support measures are of paramount importance for a favourable clinical patient outcome. The antigen detection techniques and particularly those of genetic diagnosis by amplification (PCR and others) have advanced, and improved the diagnostic of those diseases. In this paper the clinical signs and symptoms and diagnostic procedures of CNS infections are presented.

Diagnostic accuracy of a 16S ribosomal DNA gene-based molecular technique (RT-PCR, microarray, and sequencing) for bacterial meningitis, early-onset neonatal sepsis, and spontaneous bacterial peritonitis.

The diagnostic accuracy of a 16S ribosomal DNA (rDNA) gene-based molecular technique for bacterial meningitis (BM), early-onset neonatal sepsis (EONS), and spontaneous bacterial peritonitis (SBP) is evaluated. The molecular approach gave better results for BM diagnosis: sensitivity (S) was 90.6% compared to 78.1% for the bacterial culture. Percentages of cases correctly diagnosed (CCD) were 91.7% and 80.6%, respectively. For EONS diagnosis, S was 60.0% for the molecular approach and 70.0% for the bacterial culture; and CCD was 95.2% and 96.4%, respectively. For SPB diagnosis, the molecular approach gave notably poorer results than the bacterial cultures. S and CCD were 48.4% and 56.4% for the molecular approach and 80.6% and 89.1% for bacterial cultures. Nevertheless, bacterial DNA was detected in 53.3% of culture-negative samples. Accuracy of the 16S rDNA PCR approach differs depending on the sample, the microorganisms involved, the expected bacterial load, and the presence of bacterial DNA other than that from the pathogen implied in the infectious disease.

Spread of Escherichia coli O25b:H4-B2-ST131 producing CTX-M-15 and SHV-12 with high virulence gene content in Barcelona (Spain).

OBJECTIVES: The present study was carried out to evaluate the current prevalence of the clonal group O25b:H4-B2-ST131 among extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli (ESBLEC) collected in the Hospital Vall d'Hebron in Barcelona (Spain) with regard to other clonal groups and to characterize their genetic background. METHODS: Ninety-four consecutive non-duplicate ESBLEC isolates collected from May to December 2008 were studied. ESBL enzymes, phylogenetic groups, serotypes, virulence genes, sequence types (STs) and PFGE profiles were determined. Results The most prevalent ESBLs were CTX-M-14 (47%), CTX-M-15 (26%) and SHV-12 (19%). Thirty (32%) of the 94 ESBLEC isolates belonged to the clonal group O25b:H4-B2-ST131 of which 19 (63%) carried the bla(CTX-M-15) gene and eight (27%) the bla(SHV-12) gene. Moreover, five additional clonal groups (O15/O25a:H1/HNM-D-ST393, O78:HNM-A-ST369, ONT:H21,42/HNM-B1-ST101, O9:H4-A-ST410 and O8:H19-B1-ST162) were detected among 16 isolates producing CTX-M-14 and SHV-12. The 30 ST131 isolates exhibited a significantly higher virulence score (mean number of virulence genes 9.60 versus 5.84) compared with the 64 non-ST131 isolates. In particular, the SHV-12-producing ST131 isolates showed the highest virulence score (range 8-13, mean score 11.75). RESULTS: also revealed that the 30 ST131 isolates were distributed in five different groups according to their virulence, XbaI macrorestriction and resistance patterns. CONCLUSIONS: We report for the first time the clonal spread of SHV-12-producing O25b:H4-B2-ST131 isolates characterized by high virulence gene content. Moreover, we describe the distribution of the ST131 isolates within different virulence groups.

Characterisation of the CTX-M-15-encoding gene in Klebsiella pneumoniae strains from the Barcelona metropolitan area: plasmid diversity and chromosomal integration.

The localisation and genetic organisation of bla(CTX-M-15) were studied in 37 CTX-M-15-producing Klebsiella pneumoniae isolates collected from 2005 to 2008 within the Barcelona metropolitan area. Polymerase chain reaction (PCR)-based replicon typing and Southern hybridisations were used to identify the bla(CTX-M-15) location. The genetic environment was analysed by PCR mapping and sequencing, and transferability of bla(CTX-M-15) was evaluated by conjugation and transformation assays. The majority of the 37 isolates carried bla(CTX-M-15) in a plasmid location, frequently associated with the aac(6')-Ib-cr gene. Plasmids encoding bla(CTX-M-15) carried three distinct replicons, i.e. IncFII, IncR and IncFIIk, the latter two not having been described previously in association with bla(CTX-M-15). Several of these plasmids were not self-transferable. Furthermore, in all isolates belonging to sequence type ST-1, bla(CTX-M-15) was found integrated into the K. pneumoniae chromosome. In all the studied isolates, the mobile element ISEcp1 was found upstream of bla(CTX-M-15), whereas IS26 was found inserted within ISEcp1 in several isolates, in previously unreported positions. In conclusion, these findings indicate that among K. pneumoniae strains isolated in the Barcelona metropolitan area, bla(CTX-M-15) is associated with diverse genetic elements, including the IncR and IncFIIk replicons, as reported for the first time here, and the chromosome.

Phylogroups, virulence determinants and antimicrobial resistance in stx(2) gene-carrying Escherichia coli isolated from aquatic environments.

The aim of this study was to assess the prevalence of antibiotic-resistant stx(2) gene-carrying Escherichia coli isolated from human and animal wastewater with regard to their animal/human origin, serotype, phylogenetic background and virulence factors. The isolates were characterized by PCR in relation to stx variant, phylogenetic group and other virulence genes (stx(1), ehxA and saa). Antibiotic resistance was found in 92% of the stx(2) gene-carrying E. coli strains, with 77% showing intermediate resistance or full resistance to more than one antibiotic. High levels of resistance were observed to chloramphenicol, tetracycline, sulfamethoxazole, streptomycin, trimethoprim, and trimethoprim + sulfamethoxazole, with resistance values of 79%, 69%, 63%, 58%, 47% and 42%, respectively, and a higher prevalence among those strains isolated from animal wastewater. There was no association between the E. coli serotype and/or phylogroup and the antimicrobial resistance profile displayed. However, those strains carrying the stx(2) gene variant alone or in combination with other virulence factors (stx(1), ehxA or saa gene) were susceptible to most of the tested antibiotics.

Structure and urovirulence characteristics of the fecal Escherichia coli population among healthy women.

The fecal Escherichia coli population structure may influence the occurrence and etiology of extraintestinal infection, but is poorly understood. Accordingly, fecal E. coli from 39 healthy women (30 putative colonies per subject) were characterized for clonal identity, urinary tract infection-associated virulence traits, and phylogenetic background. The 120 unique E. coli clones (mean, three per sample) were distributed by phylogenetic group as follows: A (33%), D (31%), B1 (19%), and B2 (17%). However, 36% of women carried > or =1 clone from group B2, and 87% had clones from groups B2 and/or D. Of the B2 clones, 90% were from pauciclonal fecal samples (< or =4 clones), compared with 47% and 52% of A and B1 clones (P=.001 and P=.007, respectively). Group B2 and D clones more often were dominant within the source sample than group A and B1 clones (60% vs. 41%: P=.05). Dominant clones exhibited higher virulence scores than non-dominant clones (mean 4.4 vs. 3.1: P=.015). In multilevel regression models, pauciclonal sample, B2, and clonal prevalence significantly predicted virulence score. In conclusion, within the intestinal E. coli population, virulence-associated traits, clonal prevalence, and low fecal clonal diversity are related. Virulence-associated traits of group B2/D E. coli may enhance fitness within the gut, thereby increasing strains' likelihood of causing extraintestinal infection.

Role of host and bacterial virulence factors in Escherichia coli spontaneous bacterial peritonitis.

OBJECTIVES: Host factors and bacterial virulence determinants may play a role in Escherichia coli (E. coli) spontaneous bacterial peritonitis. We evaluated the importance of these factors in the emergence of fluoroquinolone-resistant strains and outcome in cirrhotic patients with E. coli spontaneous bacterial peritonitis. METHODS: E. coli spontaneous bacterial peritonitis was detected in a 2-year period in three tertiary hospitals. Clinical and bacteriological data were obtained. Phylogenetic group and 15 virulence genes of E. coli strains were analyzed by polymerase gene reaction and compared with 50 isolates from pyelonephritis patients. RESULTS: Forty-seven E. coli spontaneous bacterial peritonitis patients were identified, 18 (38%) were fluoroquinolone-resistant, a 12% increase compared with our earlier series from 1997 to 2002. Fluoroquinolone resistance was associated with norfloxacin prophylaxis, increased resistance to trimethoprim-sulfamethoxazole and cefotaxime, and less bacterial virulence, as demonstrated by a higher prevalence of 'nonpathogenic' phylogenetic groups A+B1 (56 vs. 28%; P=0.04) and lower virulence scores in fluoroquinolone-resistant E. coli compared with fluoroquinolone-susceptible E. coli. E. coli strains from cirrhotic patients belonged more frequently to 'nonpathogenic' phylogenetic groups A+B1, had fewer virulence factors and higher rates of fluoroquinolone resistance than isolates from pyelonephytis patients. Immunosuppression was independently associated with in-hospital and 3-month mortality. Bacterial virulence factors were unrelated to mortality. CONCLUSION: Fluoroquinolone-resistant E. coli spontaneous bacterial peritonitis prevalence is increasing because of norfloxacin prophylaxis. Strains from peritonitis are less virulent than strains from pyelonephritis because of a higher prevalence of A+B1 phylogeny and quinolone resistance. Mortality is related to immunosuppression, but not to bacterial virulence factors.

Relationship between Escherichia coli strains causing acute cystitis in women and the fecal E. coli population of the host.

Previous epidemiological assessments of the prevalence versus special-pathogenicity hypothesis for urinary tract infection (UTI) pathogenesis in women may have been confounded by underlying host population differences between women with UTI and healthy controls and have not considered the clonal complexity of the fecal Escherichia coli population of the host. In the present study, 42 women with acute uncomplicated cystitis served as their own controls for an analysis of the causative E. coli strain and the concurrent intestinal E. coli population. Clonality among the urine isolate and 30 fecal colonies per subject was assessed by repetitive-element PCR and macrorestriction analysis. Each unique clone underwent PCR-based phylotyping and virulence genotyping. Molecular analysis resolved 109 unique clones (4 urine-only, 38 urine-fecal, and 67 fecal-only clones). Urine clones exhibited a significantly higher prevalence of group B2 than fecal-only clones (69% versus 10%; P < 0.001) and higher aggregate virulence scores (mean, 6.2 versus 2.9; P < 0.001). In multilevel regression models for predicting urine clone status, significant positive predictors included group B2, 10 individual virulence traits, the aggregate virulence score, fecal dominance, relative fecal abundance, and (unique to the present study) a pauciclonal fecal sample. In summary, within the fecal E. coli populations of women with acute cystitis, pauciclonality, clonal dominance, virulence, and group B2 status are closely intertwined. Phylogenetic group B2 status and/or associated virulence factors may promote fecal abundance and pauciclonality, thereby contributing to upstream steps in UTI pathogenesis. This relationship suggests a possible reconciliation of the prevalence and special-pathogenicity hypotheses.

Virulence and antimicrobial resistance profiles among Escherichia coli strains isolated from human and animal wastewater.

To gain insight into whether Escherichia coli isolated from humans and resistant to some common antimicrobial agents are derived from animals, 85 E. coli strains were selected by ERIC-PCR from human and animal wastewater samples. Phylogroup, pathogenicity islands (PAIs), resistance to quinolones, fluoroquinolones and presence of extended-spectrum beta-lactamases (ESBLs) were analyzed. Among the total, 55% were resistant to nalidixic acid and 38% to ciprofloxacin; 12% produced ESBLs. Chicken-derived strains were associated with quinolone and fluoroquinolone resistance and presence of ESBLs, while human strains were associated with susceptibility. Group B2 E. coli strains were associated with human origin, susceptibility to fluoroquinolones and presence of PAIs, whereas groups A, B1 and D showed a low virulence profile and a high level of antimicrobial resistance. In both human and animal wastewater, E. coli A, B1 and D were prevalent, and strains from both origins showed a similar virulence profile in each phylogroup. These findings led us to hypothesize that abusive antibiotic use in food animal production may promote the development of resistance among these intestinal E. coli phylogroups, which could later be transmitted to humans through the food supply. The low prevalence of E. coli group B2 in the animal gut may explain, at least in part, the absence of emergence of resistant B2 isolates.

[Characterization of Escherichia coli isolates derived from phylogenetic groups A and B1 causing extraintestinal infection]. / Caracterización de Escherichia coli de los grupos filogenéticos A y B1 causantes de infección extraintestinal.

INTRODUCTION: Escherichia coli isolates from the non-pathogenic phylogenetic groups A and B1 rarely cause extraintestinal infections. The aim of this study was to analyze 37 E. coli isolates pertaining to phylogenetic groups A and B1 and compare them with 37 E. coli isolates from group B2 and 31 from group D, which caused the same infections. METHODS: Among 105 E. coli isolated from the urine of patients with cystitis and pyelonephritis and from the blood of patients with urinary-source and other-source bacteriemia, the E. coli phylogenetic groups, 15 virulence-associated genes, 7 O-antigens and fluoroquinolone resistance were analyzed. RESULTS: E. coli from groups A and B1 showed fewer virulence determinants (median 3.5) than E. coli from group B2 (8.6, P < 0.01) or D (5.3, P < .001); however, a subgroup containing 3 isolates from group A and 5 from B1 harbored 5 or more factors. E. coli from groups A/B1 were associated with resistance to fluoroquinolones (74%, P < .001), whereas E. coli from group B2 were associated with susceptibility to this antibiotic (76%, P = .003). E. coli from groups A/B1 were isolated significantly more frequently in patients with pyelonephritis or sepsis and local or general factors favoring infection, association not observed in patients with cystitis. CONCLUSIONS: Even though most of the E. coli isolates from phylogenetic groups A and B1 presented a low virulence potential, they were able to cause extraintestinal infections, particularly in compromised patients.

ESBL- and plasmidic class C beta-lactamase-producing E. coli strains isolated from poultry, pig and rabbit farms.

This study aims to determine the presence of extended-spectrum (ESBL) and plasmidic class C beta-lactamase-producing Enterobacteriaceae in poultry, pig and rabbit farms of Catalonia (Spain). PFGE typing showed a low clonal relationship among strains carrying these mechanisms of resistance. Ninety-three percent of them were resistant to two or more of the non-beta-lactam antimicrobials tested and harboured ESBL and plasmidic class C beta-lactamases. Greater diversity of these enzymes was found in strains from poultry farms, the CTX-M-9 family, especially CTX-M-14, with CMY-2 being the most frequent. The isolation of TEM-52 and SHV-2-producing Escherichia coli strains from these animal farms is noteworthy. In contrast, 73% of the strains from pig farms had CTX-M-1, and neither the CMY-type nor CTX-M-9 family enzyme was found. Likewise, it is the first time that CTX-M-1 and SHV-5 encoding strains have been isolated in pigs. On the other hand, in rabbit farms CTX-M-9 family was also the most frequent, being detected in three of a total of four strains. The last one showed a CMY-2, for the first time detected in these animals, too. In conclusion, commensal E. coli strains of food-producing animal farms are a reservoir of ESBL and plasmidic class C beta-lactamases.

Extended-spectrum beta-lactamase-producing Enterobacteriaceae in different environments (humans, food, animal farms and sewage).

OBJECTIVES: This study aimed to determine the presence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in different environments. METHODS: Clinical samples and stool samples from animal farms, sewage, human faecal carriers attending the emergency room and faecal carriers in the context of food-borne disease outbreaks were subcultured onto MacConkey agar supplemented with cefotaxime for the detection of ESBL-producing Enterobacteriaceae. Identification, susceptibility pattern and ERIC-PCR were used for clone delineation in each sample. Community consumption of antibiotics was also recorded. RESULTS: An ESBL-producing Enterobacteriaceae prevalence of 1.9% was observed in human infections. A cross-sectional survey of human faecal carriers in the community showed a general prevalence of 6.6% with a temporal distribution. High use of antibiotics in winter coincided with a lower prevalence in carriers. ESBL-producing Enterobacteriaceae were detected in the five samples of human sewage, in samples from 8 of 10 pig farms, 2 of 10 rabbit farms, from all 10 poultry farms and in 3 of 738 food samples studied. Faecal carriage of ESBL-producing Enterobacteriaceae was detected in samples from 19 of 61 food-borne outbreaks evaluated. All food-borne outbreaks were due to enteropathogens. The prevalence of carriers in these outbreaks ranged from 4.4% to 66.6%. CONCLUSIONS: This widespread occurrence of ESBL-producing Enterobacteriaceae suggests that the community could act as a reservoir and that food could contribute to the spread of these strains.

[Tuberculous meningitis: a comparative study in relation to concurrent human immunodeficiency virus infection]. / Meningitis tuberculosa: estudio comparativo en relación con la coexistencia de infección por el virus de la inmunodeficiencia humana.

INTRODUCTION: This study assesses the epidemiological and clinical data, as well as therapy and evolution in a recent series of patients with tuberculous meningitis (MT). A comparative study was conducted between adult MT patients with and without concurrent human immunodeficiency virus (HIV) infection. METHODS: From 1987 to 2000, 75 episodes of MT were diagnosed, 39 of them (52%) in patients with prior HIV infection. A comparative study was performed of variables related to the presence or absence of HIV and MT coinfection. RESULTS: MT was more frequent in HIV patients (6.4% versus 1.2%, p < 0.01). CD41 lymphocyte value in HIV patients was 52 +/- 66 cells/mm3. There were no significant differences in clinical manifestations or cerebrospinal fluid biochemical alterations between the two groups. Extrameningeal TB was more frequent in patients with HIV coinfection than those without (61.5% vs. 36.1%, p = 0.03). Radiological alterations on cranial studies were more frequent in HIV-infected patients. Treatment with four antituberculosis drugs was also more frequent in HIV-infected patients (61.5% vs. 13.9%, p = 0.01). There were no differences in adverse effects between the groups. Overall mortality (20.5% vs. 22.51%) and neurological sequelae (7.7% vs. 5.6%) were also similar. CONCLUSIONS: Half of our MT patients were coinfected with HIV. Their clinical, microbiological and evolutionary characteristics were comparable to those of patients without HIV infection. These results indicate that the diagnostic and therapeutic strategies applied in MT patients with or without HIV coinfection can be similar.

Quinolone, fluoroquinolone and trimethoprim/sulfamethoxazole resistance in relation to virulence determinants and phylogenetic background among uropathogenic Escherichia coli.

INTRODUCTION: The goal of this study was to assess how resistance to quinolones, fluoroquinolones and trimethoprim/sulfamethoxazole relates to the virulence potential and phylogenetic background of clinical Escherichia coli isolates. METHODS: Among 150 uropathogens (21% resistant to quinolones, 12% resistant to fluoroquinolones and 29.3% resistant to trimethoprim/sulfamethoxazole), E. coli phylogenetic group, 15 virulence-associated genes and 7 O antigens were analysed. Clonal group A (CGA) and genomic PCR profiles were studied among trimethoprim/sulfamethoxazole-resistant isolates. RESULTS: Isolates susceptible to the three antimicrobial agents were significantly associated with phylogenetic group B2, whereas resistant isolates exhibited shifts to non-B2 groups (quinolone and fluoroquinolone-resistant isolates to group A; trimethoprim/sulfamethoxazole-resistant isolates to group D). Diverse virulence traits, including UTI-associated O antigens, were significantly less frequent among resistant isolates, particularly those resistant to fluoroquinolones (median score, 3.9 virulence factors/strain) and also to quinolones (5.2) or trimethoprim/sulfamethoxazole (6.4), as compared with the corresponding drug-susceptible isolates (median scores of 7.9, 8.6 and 7.9, respectively). Among 44 trimethoprim/sulfamethoxazole-resistant isolates, 3 (6.8%) belonged to CGA. All these 3 CGA strains caused pyelonephritis (P=0.02) and exhibited the consensus virulence profile of previously described CGA strains from abroad. CONCLUSIONS: E. coli isolates resistant to quinolones, trimethoprim/sulfamethoxazole and especially fluoroquinolones were associated with reductions in virulence traits and shifts to non-B2 phylogenetic groups. Moreover, fluoroquinolone resistance usually occurred in low-virulence E. coli group A isolates rather than in isolates from groups B2 and D which had lost virulence traits. CGA accounted for 23% of trimethoprim/sulfamethoxazole-resistant E. coli producing pyelonephritis.

Prulifloxacin: a new antibacterial fluoroquinolone.

In the last few years, the antimicrobial activity, efficacy and relative safety of fluoroquinolones have made them attractive for the treatment of community-acquired and nosocomial infections. Prulifloxacin is a new fluoroquinolone antibacterial agent with a broad spectrum of activity against Gram-positive and -negative bacteria. Prulifloxacin is available for oral use, and after absorption is metabolized in to the active form, ulifloxacin. It exhibits good penetration in target tissues and a long elimination half-life, allowing once-daily administration. A number of randomized, controlled clinical trials carried out in Europe demonstrated the efficacy of prulifloxacin in the treatment of urinary tract (acute uncomplicated and complicated) and respiratory tract infections (acute exacerbations of chronic bronchitis), in comparison with the most widely used drugs such as ciprofloxacin, co-amoxiclav and pefloxacin. Prulifloxacin was generally well tolerated. The most frequent adverse reactions observed in clinical trials were gastric pain, diarrhea, nausea and skin rash. This review focuses on the characteristics of prulifloxacin, summarizing the relevant preclinical and clinical data.

Comparative study of Escherichia coli virulence determinants in strains causing urinary tract bacteremia versus strains causing pyelonephritis and other sources of bacteremia.

To assess the role of phylogenetic background and putative virulence factors (VFs) in Escherichia coli causing urinary bacteremia, 50 strains isolated from this condition were compared with 50 strains isolated from pyelonephritis and 50 from other sources of bacteremia. papA and papGII were significantly more prevalent in urinary bacteremia and pyelonephritis (78%, 66% and 70%, 58%) than in other-source bacteremia (48% and 24%), whereas sfa/focDE and cnf1 were more prevalent in urinary-source bacteremia (56% and 44%) than in pyelonephritis and other-source bacteremia (28%, 42% and 20%, 28%). Group B2 was the most frequent in all conditions (63% of isolates) and exhibited the greatest concentration of VFs. Urinary tract bacteremia, pyelonephritis, and other-source bacteremia isolates presented similar virulence scores (7.8, 7.0, and 6.6); however, there were striking differences among the phylogenetic groups (8.7 in group B2 versus 3.4 in group A; P < .001). Group A and B1 strains almost exclusively infected compromised hosts.

Rapid and specific detection of the O15:K52:H1 clonal group of Escherichia coli by gene-specific PCR.

Primers specific for Escherichia coli O15:K52:H1 were devised based on a novel single-nucleotide polymorphism identified within the housekeeping gene fumC, i.e., G594A. In experiments comparing various reference typing methods, the new primers provided 100% sensitivity and specificity for the O15:K52:H1 clonal group, including 162 diverse clinical and reference E. coli isolates.

Bacteriophages and diffusion of beta-lactamase genes.

We evaluated the presence of various Beta-lactamase genes within the bacteriophages in sewage. Results showed the occurrence of phage particles carrying sequences of bla(OXA-2), bla(PSE-1) or bla(PSE-4) and bla(PSE)-type genes. Phages may contribute to the spread of some Beta-lactamase genes.