High frequency of hybrid Escherichia coli strains with combined Intestinal Pathogenic Escherichia coli (IPEC) and Extraintestinal Pathogenic Escherichia coli (ExPEC) virulence factors isolated from human faecal samples.

BACKGROUND: Classification of pathogenic Escherichia coli (E. coli) has traditionally relied on detecting specific virulence associated genes (VAGs) or combinations thereof. For E. coli isolated from faecal samples, the presence of specific genes associated with different intestinal pathogenic pathovars will determine their classification and further course of action. However, the E. coli genome is not a static entity, and hybrid strains are emerging that cross the pathovar definitions. Hybrid strains may show gene contents previously associated with several distinct pathovars making the correct diagnostic classification difficult. We extended the analysis of routinely submitted faecal isolates to include known virulence associated genes that are usually not examined in faecal isolates to detect the frequency of possible hybrid strains. METHODS: From September 2012 to February 2013, 168 faecal isolates of E. coli routinely submitted to the Norwegian Institute of Public Health (NIPH) from clinical microbiological laboratories throughout Norway were analysed for 33 VAGs using multiplex-PCR, including factors associated with extraintestinal pathogenic E. coli (ExPEC) strains. The strains were further typed by Multiple Locus Variable-Number Tandem-Repeat Analysis (MLVA), and the phylogenetic grouping was determined. One isolate from the study was selected for whole genome sequencing (WGS) with a combination of Oxford Nanopore's MinION and Illumina's MiSeq. RESULTS: The analysis showed a surprisingly high number of strains carrying ExPEC associated VAGs and strains carrying a combination of both intestinal pathogenic E. coli (IPEC) and ExPEC VAGs. In particular, 93.5% (101/108) of isolates classified as belonging to an IPEC pathovar additionally carried ExPEC VAGs. WGS analysis of a selected hybrid strain revealed that it could, with present classification criteria, be classified as belonging to all of the Enteropathogenic Escherichia coli (EPEC), Uropathogenic Escherichia coli (UPEC), Neonatal meningitis Escherichia coli (NMEC) and Avian pathogenic Escherichia coli (APEC) pathovars. CONCLUSION: Hybrid ExPEC/IPEC E. coli strains were found at a very high frequency in faecal samples and were in fact the predominant species present. A sequenced hybrid isolate was confirmed to be a cross-pathovar strain possessing recognised hallmarks of several pathovars, and a genome heavily influenced by horizontal gene transfer.

Escherichia Coli Meningitis Features in 325 Children From 2001 to 2013 in France.

BACKGROUND: We aimed to describe features of Escherichia coli meningitis in a large population of children and the molecular characteristics of the involved strains to determine factors associated with severe disease or death. METHODS: Between 2001 and 2013, a prospective national survey collected data for 325 children hospitalized with E. coli meningitis. The national reference center genetically characterized 141 isolates. RESULTS: Among the 325 cases, 65.2% were term, 22.4% late preterm, and 12.5% very/extremely preterm infants. Escherichia coli meningitis was 7-fold more frequent in preterm than term infants. Median age at diagnosis was 14 days; 71.1% of infants were neonates, with 2 peaks of infection at age 0-3 days (mostly preterm neonates) and 11-15 days (mostly term neonates); 8.9% were >89 days old. In total, 51.1% patients were considered to have severe disease, and 9.2% died. B2.1 phylogenetic subgroup (56%) and O1 serogroup (27.7%) were the most frequently identified. On multivariate analysis, death was associated with preterm birth (odds ratio [OR], 3.3 [95% confidence interval {CI}, 1.3-8.4], P = .015 for late preterm infants; OR, 7.3 [95% CI, 2.7-20.9], P < .001 for very/extremely preterm infants) and cerebrospinal fluid (CSF) to blood glucose ratio <0.10 (OR, 15.3 [95% CI, 1.8-128.3], P = .012). Death was associated with uncommon O serogroup strains (P = .014) and severe disease with O7 serogroup (P = .034) and PapGII adhesin (OR, 2.3 [95% CI, 1.2-4.5], P = .015). CONCLUSIONS: In this large study of 325 cases of E. coli meningitis, risk factors of severe disease or death were preterm birth, severe hypoglycorrhachia, CSF/blood glucose ratio <0.10, and molecular characteristics of strains, which should help optimize therapeutic management.

[Epidemiology of Escherichia coli neonatal meningitis]. / Épidémiologie des méningites néonatales à Escherichia coli.

BACKGROUND: Neonatal bacterial meningitis has a mortality rate over 10 % and induces neurological sequellae in 20 to 50 % of cases. Escherichia coli (E. coli) is the second cause behind Group B streptococcus (GBS). The clinical and epidemiological features of neonatal meningitis due to E. coli between 2001 and 2010 with the data from the National Observatory are presented here. METHODS: Cases of child meningitis were prospectively collected since 2001 by a network of 252 pediatric wards associated with 166 microbiology laboratories. Risk factors, clinical signs, cerebrospinal fluid analysis, treatment and mortality were collected. RESULTS: 638 cases of neonatal bacterial meningitis were reported by 114 pediatric wards, among which 28 % (n=180) due to E. coli. If GBS prevailed in early and late-onset forms in term infants (84 % and 57 % for GBS vs 13 % and 28 % for E. coli), E. coli prevailed in preterm infants (42 % vs 37 % for GBS), and this trend increased in very preterm (GA < 33) (53 % vs 18 %). Number of E. coli early and late-onset meningitis didn't significantly vary over time. Antibiotherapy most often associated a 3(rd) generation cephalosporin, an aminosid and ciprofloxacin; sterilisation of the cerebrospinal fluid was achieved within day 2 to day 4 in 84 % of newborns. Only 3 strains were ESBL. Mortality was 11 % with E. coli, comparable to GBS (12 %) but reached 15 % in preterm infants. CONCLUSIONS: E. coli was the prevailing cause of early and late onset bacterial meningitis in premature infants, associated with a higher mortality than in term infants.

Meningitis caused by Escherichia coli producing TEM-52 extended-spectrum beta-lactamase within an extensive outbreak in a neonatal ward: epidemiological investigation and characterization of the strain.

Outbreaks caused by Enterobacteriaceae isolates producing extended-spectrum beta-lactamases (ESBL) in neonatal wards can be difficult to control. We report here an extensive outbreak in a neonatal ward with a case of meningitis caused by an ESBL-producing Escherichia coli strain. Between 24 March and 29 April 2009, among the 59 neonates present in the ward, 26 neonates with ESBL-producing E. coli rectal colonization were detected (44%). One of the colonized neonates developed meningitis with a favorable outcome after treatment combining imipenem, gentamicin, and ciprofloxacin. Despite strict intensification of hygiene and isolation procedures for more than 1 month, ward closure to new admissions was necessary to control the outbreak. Randomly amplified polymorphic DNA and pulsed-field gel electrophoresis analysis performed on 31 isolates recovered from 26 neonates and two mother's milk samples showed a clonal strain. ESBL PCR assays indicated that the strain harbored a TEM-52 ESBL encoded by an IncI1 replicon. Phylogenetic analysis by multilocus sequence typing showed that the strain belonged to rare phylogenetic group C, which is closely related to group B1 but appears as group A by the triplex PCR phylogrouping method. The strain harbored the virulence genes fuyA, aer, and iroN and was virulent in a mouse model of septicemia. This work indicates the high potential of colonization, transmission, and virulence of some ESBL-producing E. coli clones.

[Clinical outcome and bacterial characteristics of 99 Escherichia coli meningitis in young infants]. / Méningite à Escherichia coli de l'enfant : analyse descriptive clinique et microbiologique de 99 cas.

OBJECTIVE: To conduct a descriptive analysis of clinical, biological and prognostic aspects of Escherichia coli meningitis in young infants. METHODS: Clinical and biological data on young infants diagnosed with neonatal E. coli meningitis (NECM) between 1988 and 2004 were collected retrospectively and analyzed with respect to the isolates'phenotypic and genotypic characteristics. The molecular analyses focused on the phylogenetic group, the sequence-O-type, and genetic virulence traits. The virulence of lethal strains was tested in a newborn rat meningitis model. RESULTS: The median age of the 99 children analyzed was 10 days (0 to 90 days), and 83 of the patients were newborns. Thirty-three children were premature. Hyper- or hypothermia was the most frequent clinical sign at admission. Intercurrent urinary tract infection was present in 28% of cases, all over 6 days of age. 81% of blood cultures were positive. The CSF cytology was abnormal in 97% of cases. Twelve hours after admission, 34% of infants were transferred to intensive care. One-third of transfontanellar ultrasound scans done on admission were abnormal. CSH sterilization was slow in 15 % of cases, despite appropriate antibiotic therapy. The use of ciprofloxacin was associated with more rapid CSF sterilization (94 % vs 77 %, p=0.03). Six children relapsed. The average follow-up was eight months, and 21 % of children had sequelae. The case lethality rate was 14%. Fatal outcome was associated with signs of septic shock (57% vs 3%, p<10(-4)) and neurological failure (76% vs 19%, p<10(-4)) within the first 24 hours, and with abnormalities on the first ultrasound scan (63% vs 27%, p=0.03). The risk of death was higher among children infected by strains belonging to unusual sequence-O-types (50% vs 18%, p=0.01), which harbored fewer virulence factors (4.8 vs 5.9, p<10(-4)). Only aerobactin was less frequent in lethal strains (71 % vs 94%, p=0.02). Strains belonging to unusual sequence-O-types and that were lethal in the animal model induced a significantly lower level of bacteremia than strains belonging to frequent sequence-O-types (p<0.001). CONCLUSION: E. coli meningitis remains highly lethal in infants. Clinical and molecular analyses showed a link between lethality and infrequent sequence-O-types. The avirulence of these strains in animal models suggests that fatal outcome could be due to host susceptibility more than to strain virulence.

[A study of bacterial meningitis in Hokkaido between 1999 and 2003].

We evaluated 83 children with bacterial meningitis in 67 of 81 insitutions in Hokkaido, Japan between 1999 and 2003 by questionnaire. The incidence of bacterial meningitis in children aged < 5 years and 5 < or =, < 10 years was 6.3 and 0.7 cases per 100, 000 children/year. The incidences of meningitis due to Haemophilus influenzae, Streptococcus pneumoniae, and Streptococcus agalactiae in children aged < 5 years were 3.7, 1.4 and 0.8. Median age was 13 months ranging from 0 day to 9 years. Seventy-four (89.1%) of the total were less than 5 years old with 39 (47.0%) less than 1 year old. Major causative organisms were H. influenzae in 51 patients, S. pneumoniae in 18, S. agalactiae in 9 and E. coli in 3. Four deaths occurred, giving an overall case mortality rate of 4.8%. Sequelae were seen at discharge in 25.3%, predominantly epilepsy, hearing loss, and developmental delay of varying severity. The frequency of poor prognosis was 55.6% for patients with meningitis due to S. pneumoniae compared with 21.6% for H. influenzae and 22.2% for S. agalactiae.

Molecular epidemiology of Escherichia coli causing neonatal meningitis.

Escherichia coli is the second cause of neonatal meningitis which is a major cause of neonatal mortality and is associated with a high incidence of neurological sequelae. E. coli neonatal meningitis (ECNM) strains, as other extraintestinal pathogenic E. coli, mainly belong to the phylogenetic group B2 and to a lesser extent to group D, but are distributed in fewer clonal groups. One of these, the O18:K1:H7 clone is worldwide distributed meanwhile others such as O83:K1 and O45:K1 are restricted to some countries. Over the past few years, major progress has been made in the understanding of the pathophysiology of E. coli O18:K1:H7 neonatal meningitis. In particular, specific virulence factors have been identified and are known to be carried by ectochromosomal DNA in most cases. Molecular epidemiological studies, including characterization of virulence genotypes and phylogenetic analysis are important to lead to a comprehensive picture of the origins and spread of virulence factors within the population of ECNM strains. To date, all the known genetic determinants obtained in ECNM strains are not sufficient to explain their virulence in their globality and further studies on clonal groups different from the archetypal O18:K1:H7 clone are needed. These studies would serve to find common pathogenic mechanisms among different ECNM clonal groups that may be used as potential target for a worldwide efficacious prevention strategy.

Early onset neonatal meningitis in Australia and New Zealand, 1992-2002.

OBJECTIVES: To study the epidemiology of early onset neonatal bacterial meningitis (EONBM) in Australasia. DESIGN: Prospective surveillance study, 1992-2002, in 20 neonatal units in Australia and New Zealand. EONBM was defined as meningitis occurring within 48 hours of delivery. RESULTS: There were 852 babies with early onset sepsis, of whom 78 (9.2%) had EONBM. The incidence of early onset group B streptococcal meningitis fell significantly from a peak of 0.24/1000 live births in 1993 to 0.03/1000 in 2002 (p trend = 0.002). There was no significant change over time in the incidence of Escherichia coli meningitis. The rate of EONBM in very low birthweight babies was 1.09/1000 compared with the rate in all infants of 0.11/1000. The overall rate of EONBM was 0.41/1000 in 1992 and 0.06 in 2001, but this trend was not significant (p trend = 0.07). Case-fatality rates for EONBM did not change significantly with time. Birth weight <1500 g (odds ratio (OR) 7.2 (95% confidence interval (CI) 4.8 to 10.9)) and Gram negative bacillary meningitis (OR 3.3 (95% CI 2.2 to 4.9)) were significant risk factors for mortality. Sixty two percent of the 129 babies who died from early onset sepsis or suspected sepsis did not have a lumbar puncture performed. CONCLUSION: The incidence of early onset group B streptococcal meningitis has fallen, probably because of maternal intrapartum antibiotic prophylaxis, without a corresponding change in E. coli meningitis. Gram negative bacillary meningitis still carries a worse prognosis than meningitis with a Gram positive organism.

[The trend of childhood bacterial meningitis in Japan (2000-2002)].

We surveyed the epidemiology of bacterial meningitis in pediatrics between July 2000 and December 2002 in Japan and obtained the following results.: The number of cases of bacterial meningitis was 316 (182 boys and 134 girls), which was equivalent to 1.1-1.7 children out of 1,000 hospitalized those in pediatrics per year. The age-distribution for the infections was the highest under 1 year of age and it decreased as the age increased. Haemophilus influenzae was the most common pathogen causing the infections, followed by Streptococcus pneumoniae, group B streptococcus, and Escherichia coli. Relationship between causing pathogens and age-distribution was as follows: group B streptococcus and E. coli were major pathogens under 4 months of age and H. influenzae and S. pneumoniae were major pathogens over 4 months of age. Susceptibility tests performed at each facility demonstrated that 53.7% of H. influenzae isolates and 67.7% of S. pneumoniae isolates in 2003 were drug-resistant. As ampicillin and cephem antibiotics are effective against GBS, E. coli and Listeria at present, then the combination of ampicillin and cephem antibiotics was used as first line antibiotics in many facilities under 4 month of age and a combination of carbapenem which showed effective against PRSP and cephem which showed effective against H. influenzae is first choice against childhood bacterial meningitis over 4 month of age.

[Epidemiologic surveillance for bacterial meningitis in 140 000 children under 5 years of age in Nanning district, Guangxi province].

OBJECTIVE: To characterize the incidence, epidemiologic features, etiologic agents and sequelae of bacterial meningitis in children under 5 years of age in Nanning, Guangxi. METHODS: A population-based surveillance was conducted to evaluate children with signs and symptoms of meningitis. All hospitals, township health centers and village clinics in the surveillance area were structured to participate in the case referral and evaluation. Cerebrospinal fluid (CSF) and blood specimens were obtained and processed using standardized microbiologic methods. RESULTS: During the 26-month surveillance period, among the children under 5 years old, a total of 1272 cases who met the screening criteria of meningitis were studied. 265 of 1272 cases were identified as clinically diagnosed meningitis, with an incidence rate of 86.36 per 100 000 population. The annual incidence rate under the 38 cases of confirmed bacterial meningitis appeared to be 12.38/100 000. Staphylococcus species accounted for the largest proportion of laboratory-confirmed bacterial meningitis, followed by E. coli and S. pneumoniae. The highest attack rate occurred in neonates < 1 month, followed by children aged 1 - 12 months in the confirmed patients. Meningitis caused by Sp and Hi mainly occurred in children aged 1 - 12 months. All cases of meningitis due to Hi and Sp were children aged 1 - 24 months. 13.16% and 0.00% of the cases survived with complications and sequelae, and the case-fatality rate was 18.42%. 40 bacterial isolates were identified from 1193 blood cultures and 23 from 1211 cerebrospinal fluid samples, but no Neisseria meningitidis was found. CONCLUSION: Meningitis due to Hi was first confirmed in Guangxi with the incidence of 0.98 per 100 000 population. The annual incidence rate of confirmed bacterial meningitis was 12.38 per 100 000, which was considered an important public health problem in children. Staphylococci was the predominant pathogen in confirmed bacterial meningitis.

Molecular analysis and experimental virulence of French and North American Escherichia coli neonatal meningitis isolates: identification of a new virulent clone.

Phylogenetic relationships, virulence factors, alone and in specific combinations, and virulence in a rat meningitis model were examined among 132 isolates of Escherichia coli neonatal meningitis from France and North America. Isolates belonging to phylogenetic groups A (n=11), D (n=20), and B2 (n=99) had similar high prevalence rates of the siderophores aerobactin and yersiniabactin and the K1 capsule (>/=70%) yet induced different level of experimental bacteremia. Ectochromosomal DNA-like domains involved in blood-brain barrier passage (PAI III(536) [sfa/foc and iroN; 34%]; GimA [ibeA and ptnC; 38%]; PAI II(J96) [hly, cnf1, and hra; 10%]) were restricted to B2 isolates. Among group B2 isolates, representatives of the O45:K1 clonal group (n=30), which lacked these domains, were as able as the archetypal O18:K1 strain C5 to cause meningitis. Molecular epidemiology combined with experimental virulence assays demonstrate that known virulence factors are insufficient to fully explain the pathophysiology of ECNM and to allow for rational search for new virulence factors.

[The trend of childhood bacterial meningitis in Japan (1997.7-2000.6)].

We surveyed the epidemiology of purulent meningitis in pediatrics for 3 years between July 1997 and June 2000 in Japan and obtained the following results. The number of cases of purulent meningitis was 428, which was equivalent of 1.1-1.7 children out of 1,000 hospitalized those in pediatrics per year. The age-distribution for the infections was the highest under 1 year of age and it decreased as the age increased. Under 1 year of age, the highest distribution was observed in one month of age and under 1 month of age, the highest distribution was observed in 7 days of or younger ages. Haemophilus influenzae was the most common pathogen causing the infections, followed by Streptococcus pneumoniae, group B streptococcus, and Escherichia coli. Relationship between causing pathogens and age-distribution was as follows: group B streptococcus and E. coli were major pathogens under 4 months of age and H. influenzae and S. pneumoniae were major pathogens over 3 months of age. Susceptibility tests performed at each facility demonstrated that 25.3% of H. influenzae isolates and 38.7% of S. pneumoniae isolates were drug-resistant. Analysis of resistant genes for H. influenzae and S. pneumoniae isolates, which were stored and sent, demonstrated higher rates of resistance than those observed in susceptibility tests. These results suggest that the increase in insufficient efficacy of usual treatment with combination of ampicillin and cefotaxime is predictable against the infections. Therefore, the treatment for the infections should be reconsidered.

Community acquired-bacterial meningitis in adults.

We reviewed the charts of all patients > or = 15 years of age or older in whom community acquired-bacterial meningitis was diagnosed at Srinagarind Hospital, Khon Kaen, Thailand from 1984 through 1998. Eighty-five patients were included in this study. The clinical manifestation was acute meningitis with CSF neutrophilic pleocytosis and low glucose content. Gram's staining of CSF was positive in 79%. The most common pathogens were Streptococcus pneumoniae (28%) and Escherichia coli (14%) respectively. The overall mortality was 34%.

Enterobacteriaceae meningitis in adults: a review of 20 consecutive cases 1977-97.

Enterobacteriaceae are not a frequent cause of meningitis in adults and are seen mainly in neurosurgical patients and on occasion in elderly and debilitated patients. Consequently, most series studied have been small and selected. In order to obtain a clearer clinical picture, we reviewed 20 consecutive cases of Enterobacteriaceae meningitis admitted to the Department of Infectious Diseases, Rigshospitalet, Copenhagen, during the years 1977-97. They comprised 1.5% of all cases of acute bacterial meningitis admitted to the department. All of the patients were either elderly and/or had 1 or more underlying diseases and predisposing factors. The clinical presentation and cerebrospinal fluid findings were not different from that of acute bacterial meningitis in general. The mortality rate was 40% and correlated with simultaneous bacteraemia. Complications were seen in a further 30% of patients and 25% survived with different sequelae. These high rates may, at least in part, be due to the advanced age and debilitated state of the patients studied. Escherichia coli was the most frequent of the Enterobacteriaceae.