A Cohort Study of Risk Factors That Influence Empirical Treatment of Patients with Acute Pyelonephritis.

The aim of the current study was to compare community-acquired acute pyelonephritis (CA-APN) with health care-associated acute pyelonephritis (HCA-APN), describe the outcomes, and identify variables that could predict antimicrobial susceptibility. We conducted an observational study that included all consecutive episodes of acute pyelonephritis (APN) in adults during 2014 at a Spanish university hospital. From each episode, demographic data, comorbidities, clinical presentation, microbiological data, antimicrobial therapy, and outcome were recorded. A multivariable logistic regression model was performed to define the variables associated with antimicrobial resistance. A total of 607 patients, 503 (82.9%) with CA-APN and 104 (17.1%) with HCA-APN, were included in the study. Patients with HCA-APN were older than patients with CA-APN (70.4 versus 50.6 years; P < 0.001) and had higher rates of previous urinary tract infections (UTIs) (56.5% versus 24.5%; P < 0.001) and previous antibiotic use (56.8% versus 22.8%; P < 0.001). Escherichia coli was more frequently isolated from patients with CA-APN than from patients with HCA-APN (79.9% versus 50.5%; P < 0.001). The rates of resistance of Escherichia coli strains from CA-APN patients versus HCA-APN patients were as follows: amoxicillin-clavulanic acid, 22.4% versus 53.2% (P = 0.001); cefuroxime, 7.7% versus 43.5% (P = 0.001); cefotaxime, 4.3% versus 32.6% (P < 0.001); ciprofloxacin, 22.8% versus 74.5% (P < 0.001); and co-trimoxazole, 34.5% versus 58.7% (P = 0.003). The site of acquisition, recurrent UTIs, and previous antibiotic use were independent risk factors for antimicrobial resistance. Relapse rates were significantly higher when definitive antimicrobial treatment was not adequate (37.1% versus 9.3% when definitive antimicrobial treatment was adequate; P < 0.001). Our study reflects the rise of resistance to commonly used antibiotics in acute pyelonephritis. In order to choose the adequate empirical antibiotic therapy, risk factors for resistance should be considered.

Mycoplasma genitalium Macrolide and Fluoroquinolone Resistance: Prevalence and Risk Factors Among a 2013-2014 Cohort of Patients in Barcelona, Spain.

BACKGROUND: Macrolide and fluoroquinolone resistance is alarmingly emerging in M. genitalium worldwide. This article provides the first estimates of the current prevalence of macrolide and fluoroquinolone resistance-mediating mutations in Barcelona, Spain, and identifies risk factors associated with the acquisition of these resistances. METHODS: The study was conducted retrospectively with specimens submitted between February 2013 and March 2014 to the microbiology department of the Vall d'Hebron Hospital, Barcelona, where M. genitalium was detected using nucleic acid amplification methods. DNA sequencing of 23S ribosomal RNA gene and parC was performed in the Statens Serum Institut, Copenhagen, to detect genotypic macrolide and fluoroquinolone resistance markers, respectively. RESULTS: Macrolide resistance-mediating mutations were detected in 35% (95% confidence interval, 24%-47%) of the M. genitalium-positive episodes, whereas 8% (95% confidence interval, 3%-17%) carried fluoroquinolone resistance mutations. Of them, three cases harbored multidrug resistance to both classes of antibiotics. Men who had sex with men (P = 0.002) and treatment with azithromycin within the previous 12 months (P = 0.006) were strongly associated with macrolide resistance. CONCLUSION: The widespread appearance of resistances, also in Spain, makes imperative the implementation of combined diagnostic-resistance detection assays for M. genitalium to facilitate the optimization of antibiotic treatment in the management of nongonococcal urethritis and potentially reduce the transmission of resistances.

Escherichia coli early-onset sepsis: trends over two decades.

Escherichia coli early-onset sepsis (EOS) is an important cause of mortality and morbidity in neonates, especially in preterm and very low birth weight (VLBW) newborns. The aim of our study was to evaluate potential changes in the clinical and microbiological characteristics of E. coli EOS in our setting. Epidemiological, clinical, and microbiological data from all neonates with proven E. coli EOS from January 1994 to December 2014 were retrospectively collected in a single tertiary care hospital in Barcelona (Spain). Seventy-eight E. coli EOS cases were analyzed. A slight increase in the incidence of E. coli EOS was observed during the study period. VLBW newborns remained the group with higher incidence (10.4 cases per 1000 live births) and mortality (35.3%). Systematic use of PCR increased E. coli EOS diagnosis, mainly in the term newborn group. There was an increase in resistant E. coli strains causing EOS, with especially high resistance to ampicillin and gentamicin (92.8 and 28.6%, respectively). Nonetheless, resistant strains were not associated with poorer clinical outcomes. CONCLUSIONS: There is an urgent need to reconsider the empirical therapy used in neonatal EOS, particularly in VLBW newborns. What is Known: • E. coli early-onset sepsis (EOS) and E. coli resistant strains have been described as overall stable but increasing in VLBW neonates (< 1.500 g) in previous studies. What is New: • Our study shows an increasing incidence of E. coli EOS in all age groups, overruling group B Streptoccocus for the last 10 years. E. coli resistant strains also increased equally in all age groups, with high resistance rates to our first line antibiotics (ampicillin and gentamicin). • Empiric antibiotic therapy of EOS, mainly in VLBW newborns, should be adapted to this new scenario.

Long-Term Fosfomycin-Tromethamine Oral Therapy for Difficult-To-Treat Chronic Bacterial Prostatitis.

This is a retrospective study of 15 difficult-to-treat (i.e., exhibiting previous failure, patient side effects, or resistance to ciprofloxacin and co-trimoxazole) chronic bacterial prostatitis infections (5 patients with multidrug-resistant Enterobacteriaceae [MDRE]) receiving fosfomycin-tromethamine at a dose of 3 g per 48 to 72 h for 6 weeks. After a median follow-up of 20 months, 7 patients (47%) had a clinical response, and 8 patients (53%) had persistent microbiological eradication; 4/5 patients with MDRE isolates achieved eradication. There were no side effects. Fosfomycin-tromethamine is a possible alternative therapy for chronic bacterial prostatitis.

[Group B streptococcal early-onset neonatal sepsis in the area of Barcelona (2004-2010). Analysis of missed opportunities for prevention]. / Evolución de la sepsis neonatal precoz por Streptococcus agalactiae en el área de Barcelona (2004-2010). Análisis de los fallos del cumplimiento del protocolo de prevención.

OBJECTIVES: To study the evolution of the incidence of early-onset neonatal sepsis (EOS) by Streptococcus agalactiae in the area of Barcelona and to analyze failure of compliance with the prevention protocol. METHODS: A retrospective review was carried out on EOS cases in 8 Health-Care Centers in the Barcelona area between 2004 and 2010. RESULTS: Forty-nine newborns from 48 mothers were diagnosed with EOS. The incidence was 0.29‰ living newborns (0.18-0.47‰), with no significant differences in the fluctuations along the 7 years. The mortality rate was 8.16%. In 68.5% cases the maternal colonization studies were negative, and in 21% these studies were not performed. No risk factors were detected in 58.3% of pregnant women, and 22.9% of births were premature. In 58% of cases intra-partum antibiotic prophylaxis was not administered because it was not indicated, and in 42% due to failure to follow the protocol (3 strains were resistant to erythromycin). Resistance to clindamycin was 33.3%. The Streptococcus agalactiae serotypes more frequently isolated were iii, v, and ia. CONCLUSIONS: No significant changes were detected in the incidence of Streptococcus agalactiae EOS in the 7 years of the study. The increased sensitivity of screening methods with the use of molecular techniques, the performance of susceptibility testing of strains isolated from pregnant women, and the improvement of communication between Health-Care Centers, can contribute to a better implementation of the protocol, as well as to reduce the incidence of EOS.

Molecular characterization of two high-level ceftriaxone-resistant Neisseria gonorrhoeae isolates detected in Catalonia, Spain.

OBJECTIVES: The aim of this study was to characterize the first two extended-spectrum cephalosporin-resistant and multidrug-resistant (MDR) Neisseria gonorrhoeae isolates collected from two sexually related patients (men who have sex with men) in Spain. METHODS: Antimicrobial susceptibility was studied by Etest. Genes involved in quinolone, ceftriaxone and multidrug resistance were amplified by PCR and sequenced in both directions. The isolates were typed by N. gonorrhoeae multi-antigen sequence typing (NG-MAST). RESULTS: The two isolates had the same MDR profile, showing resistance to penicillin (MIC 0.094 mg/L; ß-lactamase negative), ceftriaxone (MIC 1.5 mg/L), cefixime (MIC 1.5 mg/L), cefotaxime (MIC 1 mg/L), ciprofloxacin (MIC >32 mg/L) and tetracycline (MIC 1.5 mg/L). NG-MAST showed that both isolates belonged to sequence type (ST) 1407 (porB-908 and tbpB-110). Ciprofloxacin resistance was due to amino acid substitutions in GyrA (S91F and D95G) and ParC (S87R). An A deletion in the promoter of the MtrCDE efflux pump (mtrR) was detected. No changes were detected in the pilQ gene. The outer membrane protein PorB showed two substitutions at G120K and A121N. An L421P substitution was observed in the PBP1A (ponA) sequence. The sequence of PBP2 (penA) showed a mosaic structure related to genotype XXXIV with a single additional amino acid substitution (A501P). This genotype was identical to a recently described French isolate (F89). CONCLUSIONS: This is the first reported case of high-level extended-spectrum cephalosporin-resistant N. gonorrhoeae transmission. The molecular typing and MDR genotype suggest possible European spread of this strain, highlighting the need for surveillance and the importance of testing the susceptibility of N. gonorrhoeae to extended-spectrum cephalosporins.

[Microbiological diagnosis of urinary tract infections]. / Diagnóstico microbiológico de las infecciones del tracto urinario.

For the diagnosis of urinary tract infection (UTI), besides the quantification of bacteria in the urine, cellular elements contained in the urine, the collection method used and the clinical syndrome should also be considered. Therefore, the microbiological diagnosis of UTI should be performed by an experienced person who takes into account the diversity of situations that may influence the result of each of the cultures. The processing of urine samples depends on the number of samples received daily. In laboratories with a high number, it is impossible to culture each of them, so negative urines have to be ruled out by using automated systems and cultivate only those that are positive. This review includes an analysis of the methods currently available for this screening. It also includes procedures to be performed in special situations such as prostatitis, UTI caused by fastidious microorganisms and other kind of infections that may be diagnosed in a urine test.

Isolation and characterization of potentially pathogenic antimicrobial-resistant Escherichia coli strains from chicken and pig farms in Spain.

To ascertain whether on animal farms there reside extended-spectrum beta-lactamase (ESBL) and plasmidic class C beta-lactamase-producing Escherichia coli isolates potentially pathogenic for humans, phylogenetic analyses, pulsed-field gel electrophoresis (PFGE) typing, serotyping, and virulence genotyping were performed for 86 isolates from poultry (57 isolates) and pig (29 isolates) farms. E. coli isolates from poultry farms carried genes encoding enzymes of the CTX-M-9 group as well as CMY-2, whereas those from pig farms mainly carried genes encoding CTX-M-1 enzymes. Poultry and pig isolates differed significantly in their phylogenetic group assignments, with phylogroup A predominating in pig isolates and phylogroup D predominating in avian isolates. Among the 86 farm isolates, 23 (26.7%) carried two or more virulence genes typical of extraintestinal pathogenic E. coli (ExPEC). Of these, 20 were isolated from poultry farms and only 3 from pig farms. Ten of the 23 isolates belonged to the classic human ExPEC serotypes O2:H6, O2:HNM, O2:H7, O15:H1, and O25:H4. Despite the high diversity of serotypes and pulsotypes detected among the 86 farm isolates, 13 PFGE clusters were identified. Four of these clusters contained isolates with two or more virulence genes, and two clusters exhibited the classic human ExPEC serotypes O2:HNM (ST10) and O2:H6 (ST115). Although O2:HNM and O2:H6 isolates of human and animal origins differed with respect to their virulence genes and PFGE pulsotypes, the O2:HNM isolates from pigs showed the same sequence type (ST10) as those from humans. The single avian O15:H1 isolate was compared with human clinical isolates of this serotype. Although all were found to belong to phylogroup D and shared the same virulence gene profile, they differed in their sequence types (ST362-avian and ST393-human) and PFGE pulsotypes. Noteworthy was the detection, for the first time, in poultry farms of the clonal groups O25b:H4-ST131-B2, producing CTX-M-9, and O25a-ST648-D, producing CTX-M-32. The virulence genes and PFGE profiles of these two groups were very similar to those of clinical human isolates. While further studies are required to determine the true zoonotic potential of these clonal groups, our results emphasize the zoonotic risk posed especially by poultry farms, but also by pig farms, as reservoirs of ESBL- and CMY-2-encoding E. coli.

[Laboratory unification: advantages and disadvantages for clinical microbiology]. / Unificación de los laboratorios: aportaciones y desventajas para la microbiología clínica.

This article aims to reflect on which areas or tasks of microbiology laboratories could be unified with those of clinical biochemistry, hematology, immunology or pathology laboratories to benefit patients and the health system, as well as the areas that should remain independent since their amalgamation would not only fail to provide a benefit but could even jeopardize the quality of microbiological diagnosis, and consequently patient care. To do this, the distinct analytic phases of diagnosis are analyzed, and the advantages and disadvantages of amalgamation are evaluated in each phase. The pros and cons of the unification of certain areas such as the computer system, occupational risk units, customer service, purchasing logistics, and materials storage, etc, are also discussed. Lastly, the effect of unification on urgent microbiology diagnosis is analyzed. Microbiological diagnosis should be unique. The microbiologist should perform an overall evaluation of the distinct techniques used for a particular patient, both those that involve direct diagnosis (staining, culture, antigen detection techniques or molecular techniques) and indirect diagnosis (antibody detection). Moreover, the microbiology laboratory should be independent, with highly trained technicians and specialists in microbiology that provide added value as experts in infection and as key figures in the process of establishing a correct etiological diagnosis.

Mycoplasma genitalium macrolide resistance update: Rate among a 2016-2017 cohort of patients in Barcelona, Spain.

INTRODUCTION: Mycoplasma genitalium is a major cause of urethritis and other genital syndromes. Antibiotic resistance, especially to macrolides, is increasing at an alarming rate worldwide. The aim of this study was to estimate the rate of macrolide resistance in M. genitalium among a 2016-2017 cohort of patients in Barcelona, Spain; and to compare this estimate with previous data from 2013 to 2014 in this region. METHODS: The study was conducted retrospectively with M. genitalium-positive samples collected between December 2016 and February 2017 at the Hospital Vall d'Hebron Microbiology Department. Genotypic markers of macrolide resistance were primarily detected using the ResistancePlus® MG molecular assay (SpeeDx). Mutations were then confirmed by sequencing. RESULTS: Macrolide resistance-mediating mutations were detected in 30/83 infections (36.1% [95% CI, 25.9%-47.4%]). This resistance was more frequent among men who have sex with men (55.0% [95% CI, 38.5%-70.7%]) compared to heterosexual men (27.3% [95% CI, 10.7%-50.2%]) and women (9.5% [95% CI, 1.3%-30.4%]), p<0.001. Additionally, macrolide resistance did not significantly increase in this cohort when compared with previous investigations. CONCLUSION: Despite the current notable rate of macrolide resistance in M. genitalium, resistance did not significantly increase between 2013-2014 and 2016-2017 in our region. Nevertheless, strict local surveillance and the implementation of rapid diagnostic tests that combine the detection of the bacterium and resistance-mediating mutations may facilitate the optimization of antibiotic administration and reduce the transmission of resistance in M. genitalium.

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.

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.

[Etiology of community-acquired lower urinary infections and antimicrobial resistance of Escherichia coli: a national surveillance study]. / Etiología de la infección urinaria baja adquirida en la comunidad y resistencia de Escherichia coli a los antimicrobianos de primera línea. Estudio nacional multicéntrico.

BACKGROUND AND OBJECTIVES: The increasing rates of resistance exhibited by uropathogens represent a serious problem. The aim of this study was to determine, in Spain, the etiology of community-acquired lower urinary infections and antimicrobial resistance of Escherichia coli isolates. METHODS: Prospective multicenter study conducted between February and June 2006, in 15 microbiology laboratories located in 9 autonomous regions. RESULTS: A total of 3,109 isolates were recovered. E. coli was the most frequent (70.8%), followed by Klebsiella spp (6.8%) Proteus spp (6.6%), and Enterococcus spp (5.5%). The resistant rate of E. coli for phosphomycin was 1.7%, 3.8% nitrofurantoin, 6.9% cefexime, 8.1% amoxicillin-clavulanic, 8.9% cefuroxime, and 23.9% ciprofloxacin. The 5.2% were extended-spectrum beta-lactamase (ESBL)- producing microorganisms. Resistance of E. coli to ciprofloxacin was lower in people younger than 40 years (6.7% vs 33.9% in > 60, p < 0.001), and in some regions (12.5% in Galicia vs 37.3% in Valencia). ESBL-producing E.coli was higher in people older than 60 years (79.1% vs 7% in < 40, p < 0.001), and exhibited geographic variations (18.4% in Valencia, 0.8% in Galicia). The 68.6% of ESBL-producing E.coli were resistant to cotrimoxazole, 72.2% to ciprofloxacin vs 10.6% to nitrofurantoin and 1.9% to phosphomycin. CONCLUSIONS: The increasing rates of resistance and cross-resistance of this study make evident a real problem that strengthens the need for a reevaluation of the empiric treatment of lower urinary infections.

Serotype, virulence profile, antimicrobial resistance and macrolide-resistance determinants in Streptococcus agalactiae isolates in pregnant women and neonates in Catalonia, Spain.

INTRODUCTION: Streptococcus agalactiae, or group B streptococci (GBS), is the main aetiological agent of early neonatal sepsis in developed countries. This microorganism belongs to the gastrointestinal tract microbiota wherefrom it can colonize the vagina and be vertically transmitted to the child either before or at birth, and subsequently cause infection in the newborn. Approximately, 50% of newborns born to women with GBS become colonized, with 1-2% developing early neonatal infection if no preventive intervention is performed. The aim of this study was to characterize and compare serotypes, virulence factors and antimicrobial resistance of GBS isolates collected from pregnant women and newborns in several hospitals in Catalonia. METHODS: 242 GBS strains were analyzed including 95 colonizers and 68 pathogenic strains isolated from pregnant women, and 79 strains isolated from neonates with sepsis in order to determine serotype, virulence and antimicrobial resistance. RESULTS: Serotype distribution was different among the three groups, with serotypes Ia and II being significantly more frequent among colonizing strains (p=0.001 and 0.012, respectively). Virulence factors bca and scpB were significantly more frequent among neonatal strains than pathogenic or colonizing strains (p=0.0001 and 0.002, respectively). Pathogenic strains were significantly more resistant to erythromycin, clindamycin and azithromycin than their non-pathogenic counterparts. CONCLUSIONS: Taking into account that neonatal sepsis represents a significant problem on a global scale, epidemiological surveillance, antimicrobial resistance and GBS virulence at the local level could provide important knowledge about these microorganisms as well as help to improve treatment and prevent invasive infection caused by this microorganism.

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.

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.