Spectrum of disease in bacteraemic patients during a Streptococcus pyogenes serotype M-1 epidemic in Norway in 1988

Antibiotic prescribing for adults with group A streptococcal bacteremia in a large healthcare system

Purpose

Limited data exist regarding treatment of invasive group A streptococcal (GAS) infections, including safety and efficacy of oral (PO) step-down therapy. We sought to describe current prescribing practices and clinical outcomes for patients with GAS bacteremia across a large health system, including a prespecified subset of patients who stepped down to PO antibiotics.

Methods

This retrospective cohort study included adult patients with a positive blood culture for GAS between July 2018 and July 2021. Primary outcomes included frequency of PO step-down, total duration of therapy, duration of intravenous (IV) therapy prior to PO switch, and antimicrobial selection. Secondary outcomes included length of stay (LOS), mortality, adverse events, and clinical failure leading to readmission within 90 days.

Results

In total, 280 patients met inclusion criteria. Of these, 46.7% were stepped down to PO antibiotics. Median total duration of therapy was 15 days. Median duration of IV therapy prior to PO switch was 5 days. The predominant definitive antibiotic choice was a beta-lactam. Median LOS was 5 days. Ninety-day mortality was 16.7%. One patient developed an occluded line and one developed Clostridioides difficile-associated diarrhea within 90 days. Ninety-day readmission due to clinical failure was 12.5%. Among cases of uncomplicated skin and soft tissue source, mortality (6.1% vs 2.4%) and readmission (15.2% vs 16.9%) were similar between definitive IV and PO groups.

Conclusions

Group A streptococcal bacteremia is a severe infection with a high readmission and mortality rate. Use of PO step-down therapy was common with similar readmission and mortality rates compared with definitive IV therapy.

Invasive Group A Streptococcal Infections in Children: A Nationwide Survey in Finland

BACKGROUND

The incidence of invasive group A streptococcus (iGAS) infections varies in time and geographically for unknown reasons. We performed a nationwide survey to assess the population-based incidence rates and outcomes of children with iGAS infections.

METHODS

We collected data on patients from hospital discharge registries and the electronic databases of microbiological laboratories in Finland for the period 1996-2010. We then recorded the emm types or serotypes of the strains. The study physician visited all university clinics and collected the clinical data using the same data entry sheet.

RESULTS

We identified 151 children with iGAS infection. Varicella preceded iGAS infection in 20% of cases and fasciitis infection in 83% of cases. The annual incidence rate of iGAS infection was 0.93 per 100,000 in 1996-2000, 1.80 in 2001-2005 and 2.50 in 2006-2010. The proportion of emm 1.0 or T1M1 strains peaked in 1996-2000 and again in 2006-2010, to 44% and 37% of all typed isolates. The main clinical diagnoses of the patients were severe soft-tissue infection (46%), sepsis (28%), empyema (10%), osteoarticular infection (9%) and primary peritonitis (5%). Severe pain was the most typical symptom for soft-tissue infections. More than half of the patients underwent surgery and received clindamycin. The readmission rate was 7%, and the case fatality rate was 2%.

CONCLUSIONS

The incidence rate of pediatric iGAS infections tripled during our study. The increase was not, however, the result of a change in the strain types causing iGAS. Varicella immunization would likely have prevented a significant number of the cases.

Cardiac myocyte dysfunction induced by streptolysin O is membrane pore and calcium dependent

Septic cardiomyopathy is a severe complication among some patients who develop group A streptococcal toxic shock syndrome. Despite the importance of cardiac dysfunction in determining prognosis, very little is known about mechanisms that reduce cardiac output in association with streptococcal infection. Here, we investigated the effects of streptococcal extracellular toxins on mechanical contractility of electrically paced primary murine cardiomyocytes. Our data demonstrate that streptolysin O (SLO) is the major streptococcal toxin responsible for cardiomyocyte contractile dysfunction. Streptolysin O dose-dependently affected cardiac myocyte function in discrete stages. Exposure to SLO caused a failure of cardiac cells to respond to electrical pacing, followed by spontaneous dysregulated contractions and augmented strength of contraction. Central to these SLO-mediated effects is a marked influx of calcium into the cytosol through SLO-mediated pores in the cytoplasmic membrane. Such calcium mobilization in response to SLO correlated temporally with hypercontractility and unpaced contractions. During continued exposure to SLO, cardiomyocytes exhibited periods of reversion to normal electrical pacing suggestive of membrane lesion repair and restoration of calcium handling. Together, these observations are consistent with the clinical observation that septic cardiomyopathy is a reversible condition in patients who survive streptococcal toxic shock syndrome. These data provide strong evidence that streptococcal exotoxins, specifically SLO, can directly impact cardiac mechanical function.

Evolutionary pathway to increased virulence and epidemic group A Streptococcus disease derived from 3,615 genome sequences

We sequenced the genomes of 3,615 strains of serotype Emm protein 1 (M1) group A Streptococcus to unravel the nature and timing of molecular events contributing to the emergence, dissemination, and genetic diversification of an unusually virulent clone that now causes epidemic human infections worldwide. We discovered that the contemporary epidemic clone emerged in stepwise fashion from a precursor cell that first contained the phage encoding an extracellular DNase virulence factor (streptococcal DNase D2, SdaD2) and subsequently acquired the phage encoding the SpeA1 variant of the streptococcal pyrogenic exotoxin A superantigen. The SpeA2 toxin variant evolved from SpeA1 by a single-nucleotide change in the M1 progenitor strain before acquisition by horizontal gene transfer of a large chromosomal region encoding secreted toxins NAD(+)-glycohydrolase and streptolysin O. Acquisition of this 36-kb region in the early 1980s into just one cell containing the phage-encoded sdaD2 and speA2 genes was the final major molecular event preceding the emergence and rapid intercontinental spread of the contemporary epidemic clone. Thus, we resolve a decades-old controversy about the type and sequence of genomic alterations that produced this explosive epidemic. Analysis of comprehensive, population-based contemporary invasive strains from seven countries identified strong patterns of temporal population structure. Compared with a preepidemic reference strain, the contemporary clone is significantly more virulent in nonhuman primate models of pharyngitis and necrotizing fasciitis. A key finding is that the molecular evolutionary events transpiring in just one bacterial cell ultimately have produced millions of human infections worldwide.

Streptococcus pyogenes isolates causing severe infections in Norway in 2006 to 2007: emm types, multilocus sequence types, and superantigen profiles

To investigate the epidemiological patterns and genetic characteristics of disease caused by group A Streptococcus (GAS), all available isolates from invasive cases in Norway during 2006 to 2007 (262 isolates) were subjected to antimicrobial susceptibility testing, T serotyping, emm typing, and multilocus sequence typing and screened for known streptococcal pyrogenic exotoxin (Spe) genes, smeZ, and ssa. The average incidence rate was 3.1 cases per 100,000 individuals. The most prevalent sequence types (STs) were STs 52, 28, and 334. In association with emm types 28, 77, and 87, the serotype T-28 comprised 24.8% of the strains. emm types 28, 1, and 82 were dominating. In 2007, a sharp increase in the number of emm-6 strains was noted. All strains were sensitive to penicillin and quinupristin-dalfopristin, while 3.4% and 6.1% of the strains were resistant to macrolides and tetracycline, respectively. Furthermore, the emm-6 strains had intermediate susceptibility to ofloxacin. Isolates displayed a wide variety of gene profiles, as shown by the presence or absence of the Spe genes, smeZ, and ssa, but 48% of the isolates fell into one of three profiles. In most cases, an emm type was restricted to one gene profile. Although the incidence decreased during this study, invasive GAS disease still has a high endemic rate, with involvement of both established and emerging emm types displaying variability in virulence gene profiles as well as differences in gender and age group preferences.

Epidemiological features of invasive and noninvasive group A streptococcal disease in the Netherlands, 1992-1996

A prospective, nationwide, laboratory-based surveillance of invasive group A streptococcal infections was conducted in the Netherlands from 1992 through 1996. Clinical and demographic data were obtained and all isolates were T/M typed. All noninvasive group A streptococcal isolates were registered from 1994 through 1996. A total of 880 patients with invasive streptococcal disease were identified. The annual incidence was found to be 2.2 per 100,000. Predominant M types were M1 (21%), M3 (11%), M6 (5%), M12 (5%), and M28 (8%). Particular age and M-type distributions were observed in different clinical entities. The case-fatality rate was 18% overall, but it reached 59% among cases of toxic shock-like syndrome. Older age, necrotizing fasciitis, sepsis without focus, pneumonia, infection with type M1 or M3 strains, and underlying cardiopulmonary disease were associated with fatality. A total of 10,105 patients with noninvasive group A streptococcal disease were registered. These patients differed significantly from patients with invasive disease with regard to age distribution and primary foci of infection.

Mass antibiotic treatment for group A streptococcus outbreaks in two long-term care facilities

Outbreaks of invasive infections caused by group A β-hemolytic streptococcus (GAS) may occur in long-term care settings and are associated with a high case-fatality rate in debilitated adults. Targeted antibiotic treatment only to residents and staff known to be at specific risk of GAS may be an ineffective outbreak control measure. We describe two institutional outbreaks in which mass antibiotic treatment was used as a control measure. In the first instance, mass treatment was used after targeted antibiotic treatment was not successful. In the second instance, mass treatment was used to control a rapidly evolving outbreak with a high case-fatality rate. Although no further clinical cases were seen after the introduction of mass antibiotic treatment, persistence of the outbreak strain was documented in one institution >1 year after cases had ceased. Strain persistence was associated with the presence of a chronically colonized resident and poor infection control practices.

[Necrotizing fasciitis caused by group A streptococcus]

The first case of the confirmed necrotizing fasciitis caused by Group A Streptococcus in Yugoslavia was presented. Male patient, aged 28, in good health, suddenly developed symptoms and signs of severe infective syndrome and intensive pain in the axillary region. Parenteral antibiotic, substitutional and supportive therapy was conducted along with the radical surgical excision of the necrotizing tissue. The patient did not develop streptococcal toxic shock syndrome thanks to the early established diagnosis and timely applied aggressive treatment. He was released from the hospital as completely cured two months after the admission.

Group A Streptococcus (GAS) Soft-tissue Infections: A Lethal Organism on the Rise

Several reports over the past decade have suggested that there has been an increase in the number of invasive streptococcal infections with young children and the elderly being at the highest risk. We evaluated the incidence of group A Streptococcus (GAS) and compared it with historic data collected at our institution. Prospective data were collected on patients diagnosed with GAS (with and without shock) admitted to a tertiary-care center from July 1995 to July 2000. Each patient was followed by an infectious disease specialist throughout the hospital stay. Definitions of streptococcal toxic shock syndrome (STSS) developed by the Centers for Disease Control and Prevention were used. Thirty-eight patients (mean age of 39 ± 12) presenting with GAS soft-tissue infections were admitted to our institution over a 5-year period (7.6 patients per year). Fourteen (37%) were diagnosed with STSS. This represents a greater than fourfold increase in the average number of cases per year of patients diagnosed with GAS and a nearly 4.5 times greater increase in the annual number of patients diagnosed with STSS. The overall mortality of patients diagnosed with GAS was 13 per cent, which increased to 36 per cent in patients diagnosed with STSS. We conclude that there has been a significant increase in the incidence of GAS soft-tissue infections over the past 5 years at our institution. This may represent a new virulent strain, as the majority of these infections did not occur in typical high-risk patients at the extremes of their lives. Further epidemiologic population-based studies are needed to further delineate the severe nature of this problem.

Haemorrhagic cellulitis

This report describes two cases where haemorrhagic cellulitis was managed with corticosteroids and antibiotic therapy

Population-based surveillance for group A streptococcal necrotizing fasciitis: Clinical features, prognostic indicators, and microbiologic analysis of seventy-seven cases. Ontario Group A Streptococcal Study

PURPOSE

To determine the incidence of group A streptococcal necrotizing fasciitis in Ontario, Canada, and to describe the clinical features, outcome, and microbiologic characteristics of this infection.

PATIENTS AND METHODS

Prospective, population-based surveillance for invasive group A streptococcal infections was conducted in Ontario from November 1991 to May 1995. All 77 patients meeting clinical and/or histopathologic criteria for streptococcal necrotizing fasciitis were included. Demographic and clinical information was obtained by patient interviews and chart review. Group A streptococci were characterized by M-protein and T-agglutination typing, and polymerase chain reaction (PCR) detection of streptococcal pyrogenic exotoxin genes A and C (speA; speC).

RESULTS

The incidence of group A streptococcal necrotizing fasciitis increased during the study from 0.085 per 100,000 population in the first year to 0.40 per 100,000 population in the last year (P < 0.001). The median age of cases was 57.5 years and the rate of disease increased with increasing age. Seventy-nine percent of cases were community-acquired, 11% were nosocomial, and 10% were acquired in a nursing home. Forty-seven percent of cases were associated with the presence of streptococcal toxic shock syndrome (Strep TSS) and 46% were bacteremic. Thirty-four percent of cases died and mortality was correlated with increasing age (P = 0.006), presence of hypotension (P = 0.01), and bacteremia (P = 0.03). The most common streptococcal serotypes were M1 (35%) and M3 (25%). Forty-one percent of strains possessed the speA gene and 30% the speC gene. Outcome was not correlated with M-type or the presence of spe genes.

CONCLUSIONS

The incidence of necrotizing fasciitis caused by group A streptococcus increased in Ontario between 1992 and 1995. Elderly individuals were more likely to acquire the disease and to die from it. Mortality because of streptococcal necrotizing fasciitis was also associated with the presence of hypotension, Strep TSS, or bacteremia, but not with M-type or the presence of pyrogenic exotoxin genes.

Group A streptococcal bacteremia. A 10-year prospective study

In this paper we present a prospective evaluation of 100 patients with Group A Streptococcal (GAS) bacteremia evaluated in our hospital over a 10-year period. Sixty-two patients were intravenous drug users (IVDU); all but 1 of these had an obvious cutaneous portal of entry related to the injection of illicit drugs. Twenty-seven patients had infectious metastasis, and the presence of septic pulmonary embolism was associated with suppurative phlebitis. Four of these patients had endocarditis. In the non-IVDU group, 24 patients had an underlying disease, and 12 were immunosuppressed. In 14 cases the infection was of hospital acquisition; in 35% infection was related to medical manipulations. Comparing the IVDU and non-IVDU groups, GAS bacteremia in IVDU patients is associated with a more benign outcome, a longer time of evolution before diagnosis, and a lower frequency of septic shock and mortality than in non-IVDU patients. Although in the univariate analysis GAS bacteremia was associated with several variables, in the multivariate analysis only the presence of shock and nosocomial acquisition of the infection were independently associated with a fatal outcome. Fifty-two patients were infected with human immunodeficiency virus (HIV); 5 of these were in the non-IVDU group. During the last 5 years of study, GAS bacteremia in our hospital was 39 times more frequent in HIV-infected patients than in patients without HIV. Nine patients presented clinical criteria corresponding to Streptococcal toxic shock syndrome (STSS), although its incidence was lower in the IVDU group. In the non-IVDU group, STSS was more frequent in patients with a necrotizing portal of entry, an age between 20 and 40 years, women, and when the origin of the infection was the skin or soft tissue. Six patients with STSS died, and death was associated with the presence of necrotizing lesions and lower counts of white cells, platelets, or hemoglobin.

Changing epidemiology of invasive Streptococcus pyogenes infections in southern Israel: differences between two ethnic population groups

BACKGROUND

Two ethnic populations (westernized Jews and Bedouins in transition from semi-nomadic to sedentary life conditions) living in Southern Israel and receiving inpatient services in the only medical facility of the region.

OBJECTIVE

To determine whether the incidence and severity of Streptococcus pyogenes infections among Jewish and Bedouin children have changed over the years.

STUDY DESIGN

Retrospective (1980 to 1994), population-based. Medical charts of children younger than 15 years of age hospitalized with S. pyogenes bacteremia and/or severe invasive infection were reviewed. Incidence rates of bacteremia among Jewish and Bedouin children were calculated separately.

RESULTS

The incidence of S. pyogenes bacteremia was 2.82/100,000 between 1980 and 1984, was 2.58/100,000 between 1985 and 1989 and rose significantly during 1990 through 1994 to 4.82/100,000 (P < 0.01). The observed increment was the result of a significant increase among the Jews, whereas the incidence among the Bedouin population remained relatively stable. Streptococcal toxic shock syndrome was diagnosed in three Jewish patients between 1992 and 1994. No predominance of any particular streptococcal M-type was observed.

CONCLUSIONS

The incidence of pediatric S. pyogenes bacteremia has increased in Southern Israel in recent years. This increase has occurred among the Jewish population, among which the first cases of streptococcal toxic shock syndrome have recently occurred. The increased incidence observed is not the result of dissemination of a single virulent streptococcal clone.

Systemic group B streptococcal disease in neonates and young infants in Norway 1985-94

In the period 1985-94, 237 out of 575,248 (0.41 per 1000) live born infants in Norway were reported to suffer culture-confirmed systemic group B streptococcal disease before their 90th day of life. The annual incidence increased from 0.20 per 1000 live births in 1985 to 0.64 in 1994, due solely to an increase in cases with an onset before the seventh day of life. Future studies should address the possible causes of this increase.

Necrotising fasciitis due to group A streptococci in western Norway: incidence and clinical features

During November, 1992, to May, 1994, 13 patients were treated at Haukeland University Hospital, Norway, for necrotising fasciitis due to group A beta-haemolytic streptococci. 3 patients died, 1 before admission. Mucoid group A streptococci were isolated from affected tissue (12 patients) and/or blood (5). Strains from 11 patients were serotype M-1 (5 patients), M-3 (2), M-6 (2), M-28 (1), and M-untypable (T-1, opacity factor negative) (1). For the 12 patients admitted alive, the following preoperative events were recorded: 8 had clinical signs of shock with systolic blood pressure of 90 mm Hg or less, 8 had impaired renal function, and 7 had biochemical markers of disseminated intravascular coagulation. At least 6 patients fulfilled the criteria for streptococcal toxic shock syndrome. Preoperative C-reactive protein was substantially raised ( > 200 mg/L) in 10 patients. The 12 patients were given high doses of antibiotics and were operated on with aggressive debridement of necrotic skin and fascia, 7 of them within 24 h of admission. The increasing incidence of necrotising fasciitis in western Norway reflects the resurgence of invasive group A streptococcal infections documented in Scandinavia since 1987. The high case-fatality rate can be reduced by early diagnosis and aggressive surgery combined with adequate antibiotic therapy.

Rapid detection of hyaluronic acid capsules on group A streptococci by buoyant density centrifugation

One of the virulence factors of group A streptococci is the hyaluronic acid polysaccharide capsule. A rapid method for ascertaining the status of the capsule phenotype in Streptococcus pyogenes is described. Bacteria with a capsule have a lower buoyant density than acapsular or hyaluronidase-treated cells. Early log phase cultures were underlaid with 65% Percoll and centrifuged at 500-1000 g for 5 min. Upon visual examination, encapsulated cells were observed at the interface, whereas acapsular cells appeared in the pellet. Cultures that produced at least 7 micrograms/ml of hyaluronic acid per A600 unit of cells were detected at the interface; this level of polysaccharide is only about 0.5%-4% of that found for most mucoid strains. Therefore, this procedure can detect capsules around strains that do not appear to be encapsulated by light microscopy or do not possess mucoid colony morphology. Furthermore, this method reduces dependence on other expensive assays that use labile radioactive reagents to detect hyaluronic acid.

First reported case of Streptococcus pyogenes infection with toxic shock-like syndrome in Italy

A 43-year-old male who sustained a superficial hand injury developed streptococcal toxic shock-like syndrome and died within 48 hours. The clinical course of the illness in this previously well patient was rapid and fulminant. The organism responsible was a group A beta-hemolytic streptococcus which was identified as opacity factor negative, M serotype 1, T type 1. The organism produced streptococcal pyrogenic exotoxins B and C, but no detectable exotoxin A although it carried speA, the gene for exotoxin A. This is the first case reported in Italy, and further emphasizes the virulence of these organisms and the rapidity with which the illness can progress.