Asha Tanna

Clinical and Microbiological Characteristics of Severe Streptococcus pyogenes Disease in Europe

ABSTRACT In an attempt to compare the epidemiology of severe Streptococcus pyogenes infection within Europe, prospective data were collected through the Strep-EURO program. Surveillance for severe cases of S. pyogenes infection diagnosed during 2003 and 2004 was undertaken in 11 countries across Europe by using a standardized case definition and questionnaire. Patient data as well as bacterial isolates were collected and characterized by T and M/emm typing, and selected strains were analyzed for the presence of superantigen genes. Data were analyzed to compare the clinical and microbiological patterns of the infections across the participating countries. A total of 4,353 isolates were collected from 5,521 cases with severe S. pyogenes infections who were identified. A wide diversity of M/emm types (n = 104) was found among the S. pyogenes clinical isolates, but the M/emm type distribution varied broadly between participating countries. The 10 most predominant M/emm types were M/emm type 1 (M/emm1), M/emm28, M/emm3, M/emm89, M/emm87, M/emm12, M/emm4, M/emm83, M/emm81, and M/emm5, in descending order. A correlation was found between some specific disease manifestations, the age of the patients, and the emm types. Although streptococcal toxic shock syndrome and necrotizing fasciitis were caused by a large number of types, they were particularly associated with M/emm1 and M/emm3. The emm types included in the 26-valent vaccine under development were generally well represented in the present material; 16 of the vaccine types accounted for 69% of isolates. The Strep-EURO collaborative program has contributed to enhancement of the knowledge of the spread of invasive disease caused by S. pyogenes within Europe and encourages future surveillance by the notification of cases and the characterization of strains, which are important for vaccination strategies and other health care issues.

The serotypes of Streptococcus pyogenes present in Britain during 1980–1990 and their association with disease

A total of 16,909 cultures of Streptococcus pyogenes (Lancefield group A) isolated in Britain during 1980-90 were examined for T- and M-protein antigens. One or other M antigen was detected in 92.6% of the strains. The numbers of isolates of some serotypes, such as M3 and M12, did not show great variation from year-to-year, whereas there were nationwide epidemics, extending over several years, caused by strains of serotypes M1 and M49. Isolates of serotypes M1 and M3 were associated particularly with invasive disease and fatal infections. Representatives of serotypes M80, M81 and the provisional types PT180, PT1658 and PT5757 were isolated most often from cases of pyoderma. Erythromycin resistance was detected in 30 serotypes but one half of all of the resistant isolates belonged to serotype M4.

Resistance to Macrolides in Streptococcus pyogenes in France in Pediatric Patients

ABSTRACT A total of 1,500 recent throat isolates of Streptococcus pyogenes collected between 1996 and 1999 from children throughout France were tested for their susceptibility to erythromycin, azithromycin, josamycin, clindamycin, and streptogramin B. The erythromycin-resistant isolates were further studied for their genetic mechanism of resistance, by means of PCR. The clonality of these strains was also investigated by means of serotyping and ribotyping. In all, 6.2% of the strains were erythromycin resistant, and 3.4 and 2.8% expressed the constitutive MLSB and M resistance phenotypes and harbored the ermB and mefAgenes, respectively; ermTR was recovered from one isolate which also harbored the ermB gene. Ten serotypes and 8 ribotypes were identified, but we identified 17 strains by combining serotyping with ribotyping. Among the eight ribotypes, themefA gene was recovered from six clusters, one being predominant, while the ermB gene was recovered from four clusters, of which two were predominant.

Unusual Occurrence of M Type 77, Antibiotic-Resistant Group A Streptococci in Southern Sweden

ABSTRACT For many years group A streptococci of T type 28 (T28) have been common in southern Sweden; however, since 1995 resistance to both macrolide-lincosamide-streptogramin B (MLS) antibiotics and tetracycline was observed among T28 isolates, which prompted the present studies on clonal relatedness of antibiotic-resistant T28 strains. By extended T typing, 95 of 100 examined tetracycline-resistant strains showed the combination T9-T13-T28; of these, 94 belonged to M type 77 (M77) and one belonged to M73. Three strains were T28-M28 and two were T28-M nontypeable. The serological M77 was confirmed by PCR capture enzyme-linked immunosorbent assay,emm amplicon restriction profiling, and emmsequence typing. Fifty strains were examined for superantigen genes:speA was detected in three blood isolates only, whereas all isolates harbored speB, and only two of the strains were negative for speC. Eighty-nine of the 100 strains were also macrolide resistant, of which 59 were inducibly MLS resistant (IR) and 21 were constitutively MLS resistant (CR), 6 were noninducibly resistant (NI), and 3 had novel subphenotypes recently reported by our group. Resistance genes were determined by PCR and hybridization methods. Eighty-four of the 100 strains harbored tetM. ermBwas detected in all CR and IR strains, and mefA was found in all NI strains; both ermB and mefA were identified in two strains with novel subphenotypes. Pulsed-field gel electrophoresis showed that these antibiotic-resistant M77 strains belonged to at least five different clones.

Group A Streptococcal Invasive Disease in England and Wales

During the last few years many countries have reported increases in invasive group A streptococcal (GAS) disease, particularly amongst previously healthy individuals as well as those with predisposing conditions such as immunosuppression, myelomas and varicella zoster infections5, 7, 9. The greatest change in the epidemiology of GAS disease over the years has been an expansion in the population at risk which now includes young, previously healthy adults and children as well as infants, young children, the elderly and immunocompromised individuals. In many cases severe GAS disease is associated with a specific focus such as empyema, septic arthritis, necrotising fasciitis or osteomyelitis where bacteraemia is usually documented. In 1994, much interest was stimulated by the cluster of necrotising fasciitis cases in one region of England1, 2 and, it was this incident that has led us to reassess our surveillance strategies for these diseases.

Necrotising Fasciitis Associated with Invasive Group A Streptococcal Infections in England and Wales

In the spring of 1994, a cluster of seven cases of invasive group A streptococcal (GAS) infections, including four cases of necrotising fasciitis (NF) occurred in Gloucestershire, England1. Routine surveillance data collected by the PHLS Communicable Disease Surveillance Centre (CDSC) on invasive GAS infections showed that about 550 cases were reported each year in 1991, 1992 and 1993 and there not been any increase in the spring of 19942. Data on the clinical features of cases reported to CDSC were sparse and unreliable. In the first 13 weeks of 1994, CDSC received 154 reports of isolations of GAS from blood, none of which mentioned NF, although they were known to include cases of NF. CDSC could not, therefore, provide reliable data on the number of cases of NF associated with invasive GAS infections in England and Wales.

CHARACTERISATION OF GROUP A STREPTOCOCCI FROM NECROTISING FASCIITIS CASES IN GLOUCESTERSHIRE, UNITED KINGDOM

Six cases of necrotising fasciitis (NF) five confirmed and one probable, caused by group A streptococci (GAS) in residents of Gloucestershire were reported within a three month period in 1994. Two patients died. Two cases were post operative infections which occurred following routine operations within one week. The other cases were thought to be community acquired1. As a result of this cluster of severe infections within one geographic locality a PHLS Action Group was established to discuss strategies and the implications of this incident. The group agreed a case definition for surveillance purposes and recommended that an enhanced programme of surveillance of severe group A streptococcal infections should be set up in England and Wales. This has now been successfully established. Information relating to trends in severe GAS disease at that time did not suggest that there had been a sudden increase in disease. Twenty six cases of GAS necrotising fasciitis were reported in England and Wales with dates of onset during the first six months of 1994. The case fatality rate was 69% However, routine surveillance was unable to provide a precise figure of the number of cases of NF associated with GAS infections in England and Wales prior to the Enhanced Surveillance Scheme. Data from this survey, combined with data from other countries gave estimates of 45 to 120 cases of GAS NF each year. Preliminary analysis of 847 cases of invasive GAS disease during the surveillance period of July 1994 to February 1996 has shown that they included 56 confirmed cases of NF of which 53% of patients had died.

Detection of the erythrogenic toxin A, B, and C genes in group A streptococci isolated from clinical specimens.

Erythrogenic toxins are also known as streptococcal pyrogenic exotoxins (spe) which cause a skin rash in scarlet fever (3). They also appear to be involved in the pathogenesis of severe infection (1). We investigated the detection of speA, speB, speC genes in group A streptococci (GAS) isolated from clinical specimens and in throat of school children.