Epidemiology Of Invasive Group Research Articles

The epidemiology of invasive group A streptococcal disease in Victoria, 2007–2017: an analysis of linked datasets

ObjectiveTo describe the incidence and severity of invasive group A streptococcal disease (iGAS) in Victoria, Australia. MethodsRetrospective analysis of iGAS cases identified in linked datasets, 2007–2017: laboratory data from the Victorian Hospital Pathogen Surveillance Scheme; hospitalisation data from the Victorian Admitted Episodes Dataset; and deaths reported by the Australian Coordinating Registry. ResultsThere were 1,369 confirmed and 610 probable cases of iGAS identified from 2007 to 2017 in Victoria, Australia. The median annual incidence was 3.1 (range 2.4–5.2) per 100,000 population. The incidence was highest in 2017, with 5.2 (95%CI: 4.6–5.8) cases per 100,000 population. The median length of stay in hospital was 10 days, with 33.1% (578/1,744) of cases admitted to the intensive care unit, of whom 49.5% (286/578) were mechanically ventilated. The case fatality rate was 5.6% (110/1,979), reaching 13.5% (51/378) among those aged 75 years or older. ConclusionsThere was an increased incidence of iGAS in 2017 in Victoria, with substantial healthcare utilisation and a high case fatality rate among older Victorians. Implications for public healthThese data support mandatory notification of iGAS, which will enable better characterisation of the disease, rapid identification of changes in epidemiology and targeted public health responses.

MULTIPLE CAVITATORY LUNG LESIONS DUE TO GROUP B STREPTOCOCCUS IN A HEALTHY ADULT

MULTIPLE CAVITATORY LUNG LESIONS DUE TO GROUP B STREPTOCOCCUS IN A HEALTHY ADULT

The Epidemiology of Invasive Group B Streptococcus in Denmark From 2005 to 2018.

Previous epidemiology reports on invasive Streptococcus agalactiae (GBS) infections in Denmark did not include all patient age groups. The aim of this study was therefore to analyze the GBS incidence in all age groups during the period 2005–2018 and to present the serotype distribution and the antibiotic susceptibility. Data were retrieved from the Danish laboratory surveillance system, and these included data on typing and susceptibility testing for erythromycin and clindamycin. Early-onset disease (EOD) (mean incidence 0.17 per 1,000 live births) and late-onset disease (LOD) (mean incidence 0.14 per 1,000 live births) showed a low level during the period. The incidence was stable in the age groups 91 days to 4 years, 5–19 years, and 20–64 years. From 2005 to 2018, the incidence in the elderly showed a significantly increasing trend (P < 0.05), that in the 65–74 years increased from 3.23 to 8.34 per 100,000, and that in the 75+ years increased from 6.85 to 16.01 per 100,000. Erythromycin and clindamycin resistance fluctuated over the period; however, the overall trend was increasing. Data showed that EOD and LOD incidence continued to be low, whereas an increasing trend in GBS infections in the elderly was observed. The prevalence of erythromycin and clindamycin resistance increased from 2005 to 2018.

Epidemiology of Invasive Group B Streptococcal Infections Among Nonpregnant Adults in the United States, 2008-2016

Group B Streptococcus (GBS) is an important cause of invasive bacterial disease. Previous studies have shown a substantial and increasing burden of GBS infections among nonpregnant adults, particularly older adults and those with underlying medical conditions. To update trends of invasive GBS disease among US adults using population-based surveillance data. In this population-based surveillance study, a case was defined as isolation of GBS from a sterile site between January 1, 2008, and December 31, 2016. Demographic and clinical data were abstracted from medical records. Rates were calculated using US Census data. Antimicrobial susceptibility testing and serotyping were performed on a subset of isolates. Case patients were residents of 1 of 10 catchment areas of the Active Bacterial Core surveillance (ABCs) network, representing approximately 11.5% of the US adult population. Patients were included in the study if they were nonpregnant, were 18 years or older, were residents of an ABCs catchment site, and had a positive GBS culture from a normally sterile body site. Trends in GBS cases overall and by demographic characteristics (sex, age, and race), underlying clinical conditions of patients, and isolate characteristics are described. The ABCs network detected 21 250 patients with invasive GBS among nonpregnant adults from 2008 through 2016. The GBS incidence in this population increased from 8.1 cases per 100 000 population in 2008 to 10.9 in 2016 (P = .002 for trend). There were 3146 cases reported in 2016 (59% male; median age, 64 years; age range, 18-103 years). The GBS incidence was higher among men than women and among blacks than whites and increased with age. Projected to the US population, an estimated 27 729 cases of invasive disease and 1541 deaths occurred in the United States in 2016. Ninety-five percent of cases in 2016 occurred in someone with at least 1 underlying condition, most commonly obesity (53.9%) and diabetes (53.4%). Resistance to clindamycin increased from 37.0% of isolates in 2011 to 43.2% in 2016 (P = .02). Serotypes Ia, Ib, II, III, and V accounted for 86.4% of isolates in 2016; serotype IV increased from 4.7% in 2008 to 11.3% in 2016 (P < .001 for trend). The public health burden of invasive GBS disease among nonpregnant adults is substantial and continues to increase. Chronic diseases, such as obesity and diabetes, may contribute.

Epidemiology of invasive group B streptococcal disease in infants from urban area of South China, 2011\u20132014

BackgroundGroup B Streptococcus (GBS) is a leading cause of morbidity and mortality in infants in both developed and developing countries. To our knowledge, only a few studies have been reported the clinical features, treatment and outcomes of the GBS disease in China. The severity of neonatal GBS disease in China remains unclear. Population-based surveillance in China is therefore required.MethodsWe retrospectively collected data of <3 months old infants with culture-positive GBS in sterile samples from three large urban tertiary hospitals in South China from Jan 2011 to Dec 2014. The GBS isolates and their antibiotic susceptibility were routinely identified in clinical laboratories in participating hospitals. Serotyping and multi-locus sequence typing (MLST) were also conducted for further analysis of the neonatal GBS disease.ResultsTotal 70 cases of culture-confirmed invasive GBS infection were identified from 127,206 live births born in studying hospitals, giving an overall incidence of 0.55 per 1000 live births (95% confidence interval [CI] 0.44–0.69). They consisted of 49 with early-onset disease (EOD, 0.39 per 1000 live births (95% CI 0.29–0.51)) and 21 with late-onset disease (LOD, 0.17 per 1000 live births (95% CI 0.11–0.25)). The incidence of EOD increased significantly over the studying period. Five infants (4 EOD and 1 LOD) died before discharge giving a mortality rate of 7.1% and five infants (7.1%, 2 EOD and 3 LOD) had neurological sequelae. Within 68 GBS isolates from GBS cases who born in the studying hospitals or elsewhere, serotype III accounted for 77.9%, followed by Ib (14.7%), V (4.4%), and Ia (2.9%). MLST analysis revealed the presence of 13 different sequence types among the 68 GBS isolates and ST-17 was the most frequent sequence type (63.2%). All isolates were susceptible to penicillin, ceftriaxone, vancomycin and linezolid, while 57.4% and 51.5% were resistant to erythromycin and clindamycin, respectively.ConclusionsThis study gains the insight into the spectrum of GBS infection in south China which will facilitate the development of the guidance for reasonable antibiotics usage and will provide evidence for the implementation of potential GBS vaccines in the future.

Correction for Alhhazmi et al., Epidemiology of Invasive Group B Streptococcal Disease in Alberta, Canada, from 2003 to 2013.

Volume 54, no. 7, p. [1774–1781][1], 2016, . Page 1774, abstract, lines 10 and 11: “of which the majority were hvgA positive (86.6%)” should read “of which the majority were hvgA negative (93.4%).” Page 1776, column 2, “CPS IV strains” paragraph

Group B Streptococcus (GBS) Bacteremia Likely From Infected Vaginal Pessary Causing Epidural Abscess, Endocarditis, and Septic Embolic Stroke

SESSION TITLE: Student/Resident Case Report Poster - Critical Care IV SESSION TYPE: Student/Resident Case Report Poster PRESENTED ON: Tuesday, October 25, 2016 at 01:30 PM - 02:30 PM INTRODUCTION: GBS is a gram positive coccus that colonizes in the human gastrointestinal and genital tracts (1). The reported annual incidence of GBS infection in the general population of non-pregnant adults is between 4 and 8 per 100,000 (1,2,3). In population- based surveys, invasive GBS bacteremias are responsible for 2 to 9% of heart infections and 4% of central nervous system infections (3). Indeed, 20 to 60% of invasive GBS bacteremias are fatal (3). CASE PRESENTATION: A 75 year old female with a history of Diabetes presented with 1 week of body aches, an episode of fever, and 1 to 2 days of altered mental status. Vital signs were normal. Patient was oriented, but falling to sleep during the conversation. Positive physical examination findings included 4/5 motor strength in bilateral lower extremities. Laboratory evaluation showed leukocytosis at 16,800/ microliter. Patient was started on Vancomycin and Ceftriaxone after obtaining blood cultures. CT of the head and MRI of the spine did not show any acute pathology. Cerebrospinal fluid analysis showed nucleated cells as 311 (79% neutrophils), glucose as 133 and protein as 122. Blood cultures came back as positive for Penicillin sensitive GBS with MIC of < 0.12, so the antibiotics were changed to Penicillin. Patient continued to have persistent GBS bacteremia on repeated blood cultures, so Gentamicin was added. A Trans Esophageal Echocardiogram showed small vegetation on the aortic valve. Patient's daughter visited her mother a few days after admission and revealed that patient had been having significant discomfort from vaginal pessary for a few months. Repeated blood cultures did not grow any organisms after removal of vaginal pessary, and a culture of pessary grew rare GBS. Patient's mentation and lower extremity weakness significantly deteriorated over time. Repeat MRI of brain and spine revealed acute infarction of left posterior parietal region and epidural abscess extending from T 12 to L3. Patient was emergently taken to the operating room, and epidural abscess was drained. Patient completely recovered after finishing the course of antibiotics and rehabilitation. DISCUSSION: No case of GBS bacteremia leading to epidural abscess, endocarditis, and septic embolic stroke secondary to vaginal pessary has been reported so far. In our patient, the likely source of infection was vaginal pessary; however we could not completely conclude that source, as GBS colonizes in the genital tract. CONCLUSIONS: Despite new advancements in medical technologies, a medical practitioner should never ignore the importance of history and the physical examination. Reference #1: Group B streptococcal disease in the era of intrapartum antibiotic prophylaxis. N Engl J Med. 2000;342(1):15. Reference #2: Epidemiology of invasive group B streptococcal disease in the United States, 1999-2005. JAMA. 2008;299(17):2056. Reference #3: A population-based assessment of invasive disease due to group B Streptococcus in nonpregnant adults. N Engl J Med. 1993;328(25):1807. DISCLOSURE: The following authors have nothing to disclose: Mohana Krishna Loya No Product/Research Disclosure Information

Epidemiology of invasive group A streptococcal infections in Norway 2010-2014: A retrospective cohort study.

Streptococcus pyogenes or group A streptococcus (GAS) causes mild to severe infections in humans. GAS genotype emm1 is the leading cause of invasive disease worldwide. In the Nordic countries emm28 has been the dominant type since the 1980s. Recently, a resurgence of genotype emm1 was reported from Sweden. Here we present the epidemiology of invasive GAS (iGAS) infections and their association with emm-types in Norway from 2010-2014. We retrospectively collected surveillance data on antimicrobial susceptibility, multilocus sequence type and emm-type, and linked them with demographic and clinical manifestation data to calculate age and sex distributions, major emm- and sequence types and prevalence ratios (PR) on associations between emm-types and clinical manifestations. We analysed 756 iGAS cases and corresponding isolates, with overall incidence of 3.0 per 100000, median age of 59years (range, 0-102), and male 56%. Most frequent clinical manifestation was sepsis (49%) followed by necrotizing fasciitis (9%). Fifty-two different emm-types and 67 sequence types were identified, distributed into five evolutionary clusters. The most prevalent genotype was emm1 (ST28) in all years (range, 20-33%) followed by 15% emm28 in 2014. All isolates were susceptible to penicillin, 15% resistant to tetracycline and <4% resistant to erythromycin. A PR of 4.5 (95% CI, 2.3-8.9) was calculated for emm2 and necrotizing fasciitis. All emm22 isolates were resistant to tetracycline PR 7.5 (95% CI, 5.8-9.9). This study documented the dominance of emm1, emergence of emm89 and probable import of tetracycline resistant emm112.2 into Norway (2010-2014). Genotype fluctuations between years suggested a mutual exclusive dominance of evolutionary clades.

Epidemiology of Invasive Group A Streptococcal Infections in the United States, 2005-2012.

Invasive group A Streptococcus (GAS) infections are associated with significant morbidity and mortality rates. We report the epidemiology and trends of invasive GAS over 8 years of surveillance. From January 2005 through December 2012, we collected data from the Centers for Disease Control and Prevention's Active Bacterial Core surveillance, a population-based network of 10 geographically diverse US sites (2012 population, 32.8 million). We defined invasive GAS as isolation of GAS from a normally sterile site or from a wound in a patient with necrotizing fasciitis (NF) or streptococcal toxic shock syndrome (STSS). Available isolates were emm typed. We calculated rates and made age- and race-adjusted national projections using census data. We identified 9557 cases (3.8 cases per 100 000 persons per year) with 1116 deaths (case-fatality rate, 11.7%). The case-fatality rates for septic shock, STSS, and NF were 45%, 38%, and 29%, respectively. The annual incidence was highest among persons aged ≥65 years (9.4/100 000) or <1 year (5.3) and among blacks (4.7/100 000). National rates remained steady over 8 years of surveillance. Factors independently associated with death included increasing age, residence in a nursing home, recent surgery, septic shock, NF, meningitis, isolated bacteremia, pneumonia, emm type 1 or 3, and underlying chronic illness or immunosuppression. An estimated 10 649-13 434 cases of invasive GAS infections occur in the United States annually, resulting in 1136-1607 deaths. In a 30-valent M-protein vaccine, emm types accounted for 91% of isolates. The burden of invasive GAS infection in the United States remains substantial. Vaccines under development could have a considerable public health impact.

Epidemiology of Invasive Group B Streptococcal Disease in Alberta, Canada, from 2003 to 2013.

Group B streptococci (GBS) cause severe invasive disease in both neonates and adults. Understanding the epidemiology of GBS provides information that can include determining disease prevalence rates in defined populations and geographic regions, documenting the success of GBS screening programs, and understanding antimicrobial susceptibility patterns. In Alberta, only neonatal invasive GBS (iGBS) disease is notifiable to health authorities. We performed a surveillance study of iGBS in Alberta, Canada, from 2003 to 2013. Over the 11-year period, the disease incidence rate increased from a low of 3.92 cases/100,000 population to a high of 5.99 cases/100,000 population. The capsular polysaccharide serotypes (CPSs) found were CPS III (20.3%), CPS V (19.1%), CPS Ia (18.9%), CPS Ib (12.7%), CPS II (11.1%), CPS IV (6.3%), and nontypeable GBS (9.4%). Rates of early-onset disease (0 to 7 days) increased from 0.15 cases/1,000 live births (in 2003) to 0.34 cases/1,000 live births (in 2013). Rates of late-onset disease (>7 to 90 days) also rose, from 0.15 cases/1,000 live births (in 2003) to 0.39 cases/1,000 live births (in 2013). Alberta also experienced an increase in CPS IV isolates, from 2 cases (in 2003) to 24 cases (in 2013), of which the majority were hvgA negative (93.4%) [corrected]. The predominant sequence type (ST) in 2013 was ST459. Erythromycin resistance rose from 23.6% to 43.9% (in 2013). Clindamycin resistance also increased, from 12.2% to 32.5%. In summary, Alberta, Canada, has experienced an increase in GBS disease; the increase includes both neonatal and adult disease. CPS IV cases also notably increased during the surveillance period, as did resistance to erythromycin and clindamycin.

The changing epidemiology of group B streptococcus bloodstream infection: a multi-national population-based assessment

Background Population-based studies conducted in single regions or countries have identified significant changes in the epidemiology of invasive group B streptococcus (GBS) infection. However, no studies have concurrently compared the epidemiology of GBS infections among multiple different regions and countries over time. The study objectives were to define the contemporary incidence and determinants of GBS bloodstream infection (BSI) and assess temporal changes in a multi-national population. Methods Population-based surveillance for GBS BSI was conducted in nine regions in Australia, Canada, Denmark, Sweden, Finland and the UK during 2000–2010. Incidence rates were age- and gender-standardised to the EU population. Results During 114 million patient-years of observation, 3464 cases of GBS BSI were identified for an overall annual incidence of 3.4 patients per 100 000 persons. There were marked differences in the overall (range = 1.8–4.1 per 100 000 person-year) and neonatal (range = 0.19–0.83 per 1000 live births) incidences of GBS BSI observed among the study regions. The overall incidence significantly (p = 0.05) increased. Rates of neonatal disease were stable, while the incidence in individuals older than 60 years doubled (p = 0.003). In patients with detailed data (n = 1018), the most common co-morbidity was diabetes (25%). During the study period, the proportion of cases associated with diabetes increased. Conclusions While marked variability in the incidence of GBS BSI was observed among these regions, it was consistently found that rates increased among older adults, especially in association with diabetes. The burden of this infection may be expected to continue to increase in ageing populations worldwide.

Fournier's Gangrene: Population Based Epidemiology and Outcomes

Case series have shown a Fournier's gangrene mortality rate of 20% to 40% with an incidence of as high as 88% in some studies. Because to our knowledge there are no population based data, we used a national database to investigate the epidemiology of Fournier's gangrene. We used the State Inpatient Databases, the largest hospital based database available in the United States, which includes 100% of hospital discharges from participating states. Inpatients diagnosed with Fournier's gangrene (ICD-9 CM 608.83) who underwent genital/perineal débridement or died in the hospital were identified from 13 participating states in 2001 and from 21 in 2004. Population based incidence, regional trends and case fatality rates were estimated. We identified 1,641 males and 39 females with Fournier's gangrene. Cases represented less than 0.02% of hospital admissions. The overall incidence was 1.6/100,000 males, which peaked in males who were 50 to 79 years old (3.3/100,000) with the highest rate in the South (1.9/100,000). The overall case fatality rate was 7.5%. Patients with Fournier's gangrene were rarely treated at hospitals (mean +/- SD 0.6 +/- 1.2 per year, median 0, range 0 to 23). Overall 0 to 4 and 5 or greater cases were treated at 66%, 17%, 10%, 4%, 1% and 1% of hospitals, respectively. Patients with Fournier's gangrene are rarely treated at most hospitals. The population based mortality rate of 7.5% was substantially lower than that reported in case series from tertiary care centers.

Epidemiology of Invasive Group B Streptococcal Disease in the United States, 1999-2005

Epidemiology of Invasive Group B Streptococcal Disease in the United States, 1999-2005

Trends in Group B Strep Disease in the US: Better for Newborns, Worse for Adults; Phares CR, Lynfield R, Farley MM, Mohle‐Boetani J, Harrison LH, Petit S, et al. Epidemiology of invasive group B streptococcal disease in the United States, 1999–2005. JAMA 2008;299:2056–65

Trends in Group B Strep Disease in the US: Better for Newborns, Worse for Adults; Phares CR, Lynfield R, Farley MM, Mohle‐Boetani J, Harrison LH, Petit S, et al. Epidemiology of invasive group B streptococcal disease in the United States, 1999–2005. JAMA 2008;299:2056–65

Epidemiology of Invasive Group B Streptococcal Disease in the United States, 1999-2005

Group B streptococcus is a leading infectious cause of morbidity in newborns and causes substantial disease in elderly individuals. Guidelines for prevention of perinatal disease through intrapartum chemoprophylaxis were revised in 2002. Candidate vaccines are under development. To describe disease trends among populations that might benefit from vaccination and among newborns during a period of evolving prevention strategies. Analysis of active, population-based surveillance in 10 states participating in the Active Bacterial Core surveillance/Emerging Infections Program Network. Age- and race-specific incidence of invasive group B streptococcal disease. There were 14,573 cases of invasive group B streptococcal disease during 1999-2005, including 1348 deaths. The incidence of invasive group B streptococcal disease among infants from birth through 6 days decreased from 0.47 per 1000 live births in 1999-2001 to 0.34 per 1000 live births in 2003-2005 (P < .001), a relative reduction of 27% (95% confidence interval [CI], 16%-37%). Incidence remained stable among infants aged 7 through 89 days (mean, 0.34 per 1000 live births) and pregnant women (mean, 0.12 per 1000 live births). Among persons aged 15 through 64 years, disease incidence increased from 3.4 per 100,000 population in 1999 to 5.0 per 100,000 in 2005 (chi2(1) for trend, 57; P < .001), a relative increase of 48% (95% CI, 32%-65%). Among adults 65 years or older, incidence increased from 21.5 per 100,000 to 26.0 per 100,000 (chi2(1) for trend, 15; P < .001), a relative increase of 20% (95% CI, 8%-35%). All 4882 isolates tested were susceptible to penicillin, ampicillin, and vancomycin, but 32% and 15% were resistant to erythromycin and clindamycin, respectively. Serotypes Ia, Ib, II, III, and V accounted for 96% of neonatal cases and 88% of adult cases. Among infants from birth through 6 days, the incidence of group B streptococcal disease was lower in 2003-2005 relative to 1999-2001. This reduction coincided with the release of revised disease prevention guidelines in 2002. However, the disease burden in adults is substantial and increased significantly during the study period.

Epidemiology of Invasive Group A Streptococcal Infection in the United States

Epidemiology of Invasive Group A Streptococcal Infection in the United States

Epidemiology of Invasive Group B Streptococcal Disease in the United States, 1999-2005

Epidemiology of Invasive Group B Streptococcal Disease in the United States, 1999-2005

The Epidemiology of Invasive Group A Streptococcal Infection and Potential Vaccine Implications: United States, 2000-2004

Invasive group A Streptococcus (GAS) infection causes significant morbidity and mortality in the United States. We report the current epidemiologic characteristics of invasive GAS infections and estimate the potential impact of a multivalent GAS vaccine. From January 2000 through December 2004, we collected data from Centers for Disease Control and Prevention's Active Bacterial Core surveillance (ABCs), a population-based system operating at 10 US sites (2004 population, 29.7 million). We defined a case of invasive GAS disease as isolation of GAS from a normally sterile site or from a wound specimen obtained from a patient with necrotizing fasciitis or streptococcal toxic shock syndrome in a surveillance area resident. All available isolates were emm typed. We used US census data to calculate rates and to make age- and race-adjusted national projections. We identified 5400 cases of invasive GAS infection (3.5 cases per 100,000 persons), with 735 deaths (case-fatality rate, 13.7%). Case-fatality rates for streptococcal toxic shock syndrome and necrotizing fasciitis were 36% and 24%, respectively. Incidences were highest among elderly persons (9.4 cases per 100,000 persons), infants (5.3 cases per 100,000 persons), and black persons (4.7 cases per 100,000 persons) and were stable over time. We estimate that 8950-11,500 cases of invasive GAS infection occur in the United States annually, resulting in 1050-1850 deaths. The emm types in a proposed 26-valent vaccine accounted for 79% of all cases and deaths. Independent factors associated with death include increasing age; having streptococcal toxic shock syndrome, meningitis, necrotizing fasciitis, pneumonia, or bacteremia; and having emm types 1, 3, or 12. GAS remains an important cause of severe disease in the United States. The introduction of a vaccine could significantly reduce morbidity and mortality due to these infections.

The epidemiology of invasive group A streptococcal disease in Victoria, Australia

To estimate the incidence and severity of invasive group A streptococcal infection in Victoria, Australia. Prospective active surveillance study. Public and private laboratories, hospitals and general practitioners throughout Victoria. People in Victoria diagnosed with group A streptococcal disease notified to the surveillance system between 1 March 2002 and 31 August 2004. Confirmed invasive group A streptococcal disease. We identified 333 confirmed cases: an average annual incidence rate of 2.7 (95% CI, 2.3-3.2) per 100,000 population per year. Rates were highest in people aged 65 years and older and those younger than 5 years. The case-fatality rate was 7.8%. Streptococcal toxic shock syndrome occurred in 48 patients (14.4%), with a case-fatality rate of 23%. Thirty cases of necrotising fasciitis were reported; five (17%) of these patients died. Type 1 (23%) was the most frequently identified emm sequence type in all age groups. All tested isolates were susceptible to penicillin and clindamycin. Two isolates (4%) were resistant to erythromycin. The incidence of invasive group A streptococcal disease in temperate Australia is greater than previously appreciated and warrants greater public health attention, including its designation as a notifiable disease.

Invasive group A streptococcal infections in the San Francisco Bay area, 1989–99

To describe the epidemiology of invasive group A streptococcal (iGAS) infections in the San Francisco Bay Area, population-based active surveillance for laboratory-confirmed iGAS was conducted by the California Emerging Infections Program in three California counties. From January 1989 to December 1999, 1415 cases of iGAS were identified. Mean iGAS incidence was 4.06/100,000 person-years and case fatality ratio was 13%, with no linear trends over time. Incidence was lowest in adolescents, was higher in men than women (4.4 vs. 3.2/100,000 person-years), and was higher in African-Americans (6.7) than in non-Hispanic (4.1) or Hispanic (3.4) Whites, Asians (2.2) or Native Americans (17/100,000 person-years). Injecting drug use was the riskiest underlying condition and was associated with the highest attributable risk. Cases were associated with several underlying conditions, but 23% occurred in previously healthy persons. From 1989-1999, iGAS infections in the San Francisco Bay Area became neither more common nor more deadly.