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Androulla Efstratiou

Publications and source records attributed to Androulla Efstratiou.

At least 19 recordsLinked to original sources
PubMed2006

Molecular epidemiology of C. diphtheriae strains during different phases of the diphtheria epidemic in Belarus.

BACKGROUND: The reemergence of epidemic diphtheria in Belarus in 1990s has provided us with important information on the biology of the disease and the diversity of the causative agent Corynebacterium diphtheriae. Molecular investigations were conducted with the aim to analyze the genetic variability of C diphtheriae during the post-epidemic period. METHODS: The biotype and toxigenicity status of 3513 C. diphtheriae strains isolated from all areas in Belarus during a declining period of diphtheria morbidity (1996-2005) was undertaken. Of these, 384 strains were isolated from diphtheria cases, 1968 from tonsillitis patients, 426 from contacts and 735 from healthy carriers. Four hundred and thirty two selected strains were ribotyped. RESULTS: The C diphtheriae gravis biotype, which was prevalent during 1996-2000, was "replaced" by the mitis biotype during 2001-2005. The distribution of toxigenic C. diphtheriae strains also decreased from 47.1% (1996) to 5.8% (2005). Changes in the distribution of the epidemic ribotypes Sankt-Peterburg and Rossija were also observed. During 2001-2005 the proportion of the Sankt-Peterburg ribotype decreased from 24.3% to 2.3%, in contrast to the Rossija ribotype, that increased from 25.1% to 49.1%. The circulation of other toxigenic ribotypes (Otchakov, Lyon, Bangladesh), which were prevalent during the period of high diphtheria incidence, also decreased. But at the same time, the proportion of non-toxigenic strains with the Cluj and Rossija ribotypes dramatically increased and accounted for 49.3% and 30.1%, respectively. CONCLUSION: The decrease in morbidity correlated with the dramatic decrease in the isolation of the gravis biotype and Sankt Peterburg ribotype, and the prevalence of the Rossija ribotype along with other rare ribotypes associated with non-toxigenic strains (Cluj and Rossija, in particular).

Corynebacterium diphtheriae↗
PubMed2006

Molecular characterization of clinical isolates of M non-typable group A streptococci from invasive disease cases.

Currently there are 93 validated M serotypes of Streptococcus pyogenes, Lancefield group A streptococcus (GAS), and >130 emm genotypes. A marked increase in the number of non-typable GAS isolates (2 % in 2000, 4 % in 2001 and 9 % in 2002) from invasive disease cases referred to the authors' reference laboratory was noted during 2000-2002. A total of 217 (92 %) were from blood cultures, 14 (6 %) from deep abscesses and five (2 %) from aspirates. The clinical manifestations included bacteraemia, septicaemia, cellulitis, meningitis, necrotizing fasciitis and toxic-shock syndrome. In order to establish whether this increase was due to the emergence of novel types or the unavailability of M-typing sera, these isolates were subjected to emm sequencing. A total of 144 isolates (61 %) belonged to M types for which sera were no longer available; 112 (48 %) belonged to higher M types, including emm83.1 (9 %), emm94 (8 %) emm87 (6 %) and emm89 (6 %); and 32 (13 %) belonged to lower M types that were not commonly isolated in the UK, and included M25, M43, M49, M64, M73 and M74. Sixty-six (28 %) of the isolates belonged to newly designated emm types. Other isolates belonged to the novel emm types st2147, STNS1033 and st854, recently registered in the Centers for Disease Control (CDC) database by other laboratories. One novel emm type, st2161, was isolated from an injecting drug user. There were differences in the type distribution of these isolates according to geographic location. However, 90 % of emm93, one of seven predominant emm types identified amongst the collection of M non-typable (MNT) isolates, were isolated from the London region.

Abscess↗
PubMed2005

Molecular characterization of diphtheria toxin repressor (dtxR) genes present in nontoxigenic Corynebacterium diphtheriae strains isolated in the United Kingdom.

Nontoxigenic strains of Corynebacterium diphtheriae represent a potential reservoir for the emergence of toxigenic C. diphtheriae strains if they possessed functional diphtheria toxin repressor (dtxR) genes. We studied the predominant strain of nontoxigenic C. diphtheriae circulating in the United Kingdom to see if they possessed dtxR genes and ascertain whether they were functional. A total of 26 nontoxigenic C. diphtheriae strains isolated in the United Kingdom during 1995 and 4 nontoxigenic strains isolated in other countries were analyzed by PCR and direct sequencing to determine the presence and intactness of the dtxR genes. The functionality of the DtxR proteins was assayed by testing for the production of siderophore in medium containing high and low concentrations of iron. PCR amplification and sequence analysis of the dtxR genes revealed four variants of the predicted DtxR protein among the nontoxigenic strains isolated in the United Kingdom. Production of siderophore in medium containing a low concentration of iron and repression of siderophore production in medium containing a high concentration of iron demonstrated that in all the strains the dtxR genes were functional. These findings demonstrate that, if lysogenised by a bacteriophage, nontoxigenic strains circulating in the United Kingdom could produce toxin and therefore represent a potential reservoir for toxigenic C. diphtheriae.

Amino Acid Sequence↗
PubMed2005

Characterization of toxigenic Corynebacterium ulcerans strains isolated from humans and domestic cats in the United Kingdom.

In the United Kingdom there has been a marked increase in the number of human infections caused by toxigenic Corynebacterium ulcerans. During 2002 and 2003 the organism was also isolated from several domestic cats with bilateral nasal discharge. As C. ulcerans has never previously been isolated from cats, the 16S rRNA gene from three cat isolates was sequenced to confirm their species identities. Fifty clinical isolates from the United Kingdom isolated from 1986 to 2003 and seven cat isolates were characterized by ribotyping to determine whether the ribotypes of the cat isolates were genotypically related to those found for human clinical isolates. For comparison, the genotypes of 11 overseas isolates and 13 isolates from H. R. Carne's collection isolated between 1933 and 1979 were also determined. Strains isolated from domestic cats were found to exhibit the predominant ribotypes observed among human clinical isolates, suggesting that C. ulcerans isolated from cats could be a potential reservoir for human infection.

Adolescent↗
PubMed2004

Characterization of group B streptococci recovered from infants with invasive disease in England and Wales.

Group B streptococci (GBS) are a major cause of invasive disease in infants, with enhanced surveillance in England and Wales showing an incidence of 0.74 cases per 1000 live births and a mortality rate of 8%. Among 353 isolates obtained during enhanced surveillance, the predominant serotypes were III (48%), Ia (27%), and V (10%), and the remainder comprised Ib, II, IV, VI, and VII; 3% were not typable. Isolates from patients with early-onset disease had serotypes III (38%), Ia (32%), and V (13%), with late-onset disease having a higher incidence of type III (67%) strains. Patients infected with serotype III strains had a higher rate of meningitis, and those with type V strains had a higher mortality rate. Isolates were susceptible to penicillin and ampicillin, but 4% were resistant to erythromycin, and 91% were resistant to tetracycline. A trivalent vaccine containing capsular polysaccharides III, Ia, and V could theoretically provide coverage against 85% of the cases of GBS disease among infants in England and Wales.

Anti-Bacterial Agents↗
PubMed2004

Group B streptococcal disease in UK and Irish infants younger than 90 days.

The incidence, morbidity, and mortality of group B streptococcal disease in the UK and Republic of Ireland are largely unknown. Between Feb 1, 2000, and Feb 28, 2001, we identified cases of invasive group B streptococcal disease in infants younger than 90 days through surveillance involving paediatricians, microbiologists, and parents. 568 cases were identified, equivalent to a total incidence of 0.72 per 1000 live-births (95% CI 0.66-0.78); the incidence for early-onset disease (n=377) was 0.48 per 1000 (0.43-0.53), and for late-onset disease (n=191) was 0.24 per 1000 (0.21-0.28). Risk factors were identifiable for 218 (58%) cases of early-onset disease. 53 infants died (overall 9.7%). We have established the minimum current burden of group B streptococcal disease in UK and Irish infants. This information will assist in the formulation of guidelines for prevention of this disease.

Female↗
PubMed2004

Early-onset neonatal group B streptococcal infection in London: 1990-1999.

OBJECTIVE: To identify the incidence of early-onset group B streptococcal infection and to describe the antecedent maternal risk factors, in order to provide data to inform the design of interventional strategies that could be introduced in the UK to reduce the burden of this infection. DESIGN: A retrospective study with review of case notes of mothers and babies. SETTING: Seven maternity units in London during 1990-1999. Population All cases of proven early-onset neonatal group B streptococcal infection. METHODS: Identification of presence of risk factors that could be used to select women for the offer of intrapartum antibiotic prophylaxis. MAIN OUTCOME MEASURES: Incidence and case-fatality rate of invasive early-onset group B infection. RESULTS: One hundred and forty cases were identified among a birth cohort of 198,388 live births, an incidence of 0.71 per 1000 live births. Twenty-two babies died, a case-fatality rate of 15.6% or 1.1 per 100,000 live births. Women of black ethnic origin, and those who had had a previously affected infant, multiple pregnancy, preterm delivery, prolonged rupture of membranes or intrapartum fever all had a significantly increased risk of delivering an infected infant. CONCLUSIONS: These data suggest that the incidence of early-onset group B streptococcal infection in these London centres is sufficiently high to warrant administration of intrapartum antibiotics to at-risk women.

Cross Infection↗
PubMed2004

Imported cutaneous diphtheria, United Kingdom.

Cutaneous diphtheria is endemic in tropical countries but unusual in the United Kingdom. Four cases occurred in the United Kingdom within 2 months in 2002. Because cutaneous diphtheria causes outbreaks of both cutaneous and pharyngeal forms, early diagnosis is essential for implementing control measures; high diphtheria vaccination coverage must also be maintained.

Adult↗
PubMed2004

Eighth International Meeting of the European Laboratory Working Group on Diphtheria and the Diphtheria Surveillance Network--June 2004: progress is needed to sustain control of diphtheria in European Region.

The Eighth International Meeting of the European Laboratory Working Group on Diphtheria (ELWGD) and the Diphtheria Surveillance Network (DIPNET) was held and co-organised with the WHO Regional Office for Europe, Copenhagen, Denmark, in June 2004. This article provides an international updated review of progress in clinical, epidemiological and microbiological aspects of diphtheria in the European region as presented at the meeting. It highlights the need for improved immunisation coverage, surveillance and epidemiological studies to sustain control of diphtheria in European Region.

Corynebacterium↗
PubMed2003

Molecular epidemiology and characteristics of Corynebacterium diphtheriae and Corynebacterium ulcerans strains isolated in Italy during the 1990s.

Five cases of diphtheria were reported in Italy between January 1990 and June 2001. Three cases were confirmed microbiologically by the isolation of toxigenic Corynebacterium diphtheriae (two cases) and Corynebacterium ulcerans (one case). Over the same period, 11 cases of non-toxigenic C. diphtheriae infection were reported to the Italian Public Health Institute, from which the causative organism was isolated from a skin infection in one case and from the throat in the other ten. Seven of the throat isolates were associated with fever, severe pharyngitis and tonsillitis and were all biotype gravis. Because there are no standardized breakpoints, the antimicrobial sensitivities of C. diphtheriae were determined in accordance with the National Committee for Clinical Laboratory Standards guidelines for Streptococcus spp. other than Streptococcus pneumoniae. MICs for penicillin ranged between 0.125 and 0.250 mg l(-1) and 7 out of 11 strains had a minimal bactericidal concentration (MBC)/MIC ratio >or= 32. All strains were sensitive to clindamycin (MIC <or= 0.25 mg l(-1)), rifampicin (MIC <or= 1 mg l(-1)) and tetracycline (MIC <or= 2 mg l(-1)), and showed moderate susceptibility to cefotaxime (MIC 0.75-1.5 mg l(-1)). Molecular typing (ribotyping) demonstrated the presence of several distinct ribotypes. The ribotype designated 'D11' has been documented amongst strains isolated in the UK, Russia, Germany, Romania and Sweden. Ribotype 'D75' has only been documented in the UK. The C. ulcerans strain had a ribotype pattern identical to that found in recent isolates from the UK.

Colony Count, Microbial↗
PubMed2003

Increasing incidence of group A streptococcal infections amongst injecting drug users in England and Wales.

During 2000, the UK witnessed a sudden increase in severe infections and related deaths in injecting drug users (IDUs), sparking off a UK-wide investigation. A worrying upward trend in severe group A streptococcal (GAS) infections has recently been observed in IDUs based upon isolate referrals to the PHLS Respiratory and Systemic Infection Laboratory. Most cases were young male adults who presented with skin sepsis and bacteraemia. Serotyping revealed a diverse range of M types, with higher types predominating in some geographical areas. The data suggest that GAS invasive soft-tissue infections may present in an epidemic fashion among IDUs in the absence of a common source.

Adult↗
PubMed2003

Genotypic and phenotypic characteristics of Corynebacterium diphtheriae strains isolated from patients in belarus during an epidemic period.

One hundred two Corynebacterium diphtheriae strains (93 of the gravis biotype and nine of the mitis biotype) isolated from clinical cases during the Belarus diphtheria epidemic were characterized by biotyping, toxigenicity testing by the Elek test and an indirect hemagglutination assay, phage typing, and ribotyping. The gravis biotype strains were characterized as high and medium toxin producers, and strains of biotype mitis were characterized as low and medium toxin producers. Most strains (82 of 102) were distributed among five phage types. Seventy-two strains (64 of the gravis biotype and 8 of the mitis biotype) belonged to phage type VI ls5,34add. Hybridization of genomic DNA digested with BstEII and PvuII revealed five ribotype patterns, namely, D1, D4, D6, D7, and D13. The majority of gravis biotype strains belonged to ribotypes D1 (49 of 93) and D4 (33 of 93) and included one clonal group of C. diphtheriae. This clone predominated in all regions in Belarus. There was a statistical association between ribotypes and phage types but not between ribotypes and levels of toxin production.

Bacterial Typing Techniques↗
PubMed2001

Extension of the Lancefield classification for group A streptococci by addition of 22 new M protein gene sequence types from clinical isolates: emm103 to emm124.

Classic M protein serotyping has been invaluable during the past 60 years for the determination of relationships between different group A streptococci (GAS) strains and the varied clinical manifestations inflicted by these organisms worldwide. Nonetheless, during the past 20 years, the difficulties of continued expansion of the serology-based Lancefield classification scheme for GAS have become increasingly apparent. By use of a less demanding sequence-based methodology that closely adheres to previously established strain criteria while being predictive of known M protein serotypes, we recently added types emm94-emm102 to the Lancefield scheme. Continued expansion by the addition of types emm103 to emm124 are now proposed. As with types emm94-emm102, each of these new emm types was represented by multiple independent isolates recovered from serious disease manifestations, each was M protein nontypeable with all typing sera stocks available to international GAS reference laboratories, and each demonstrated antiphagocytic properties in vitro by multiplying in normal human blood.

Antigens, Bacterial↗
PubMed2001

International external quality assessment scheme for the laboratory diagnosis of diphtheria.

An international external quality assessment (EQA) scheme has been established so as to evaluate the proficiency of specialist, national diphtheria reference laboratories in the laboratory diagnosis of diphtheria. Six simulated clinical specimens were freeze-dried and distributed to 23 participants in 20 countries. Participants were asked to isolate, identify and perform toxigenicity testing on any corynebacteria present and to complete a simple questionnaire describing the procedures and reagents used. Only three laboratories obtained correct biochemical and toxigenicity results for all six specimens. The majority of laboratories performed better with toxigenicity testing than with the biochemical identification. Of concern were the results from three laboratories that failed to isolate any corynebacteria from four or more of the specimens. In one centre this was shown to be due to lack of availability of 'in-date' media and, in the other two, was presumed to be due to lack of experience in primary laboratory diagnostics for this organism. It is essential that countries, globally, maintain awareness and laboratory capabilities in this specialised area of microbiology. EQA is an invaluable process, which enables laboratories to monitor, evaluate and improve their own performance in such areas.

Clinical Laboratory Techniques↗