Major risk factors for Streptococcus dysgalactiae subsp. equisimilis bacteremia: a population-based study

BACKGROUND

Streptococcus dysgalactiae subspecies equisimilis is a human pathogen causing severe invasive infections. Detailed information on S. dysgalactiae subsp. equisimilis bacteremia and especially of predisposing factors are lacking. The purpose of the study is to investigate the risk factors of S. dysgalactiae subsp. equisimilis bacteremia compared to the general population in Finland.

METHODS

We retrospectively reviewed all patients older than 18 years with S. dysgalactiae subsp. equisimilis bacteremia in the Pirkanmaa health district from August 2015 to July 2018. The risk factors for S. dysgalactiae subsp. equisimilis bacteremia were investigated with respect to the normal population in Finland using the Finhealth study data provided by the Finnish institute for health and welfare. The study group was matched with the Finhealth study by age and sex.

RESULTS

Altogether 230 cases of S. dysgalactiae subsp. equisimilis bacteremia were detected. The medical records of 217 episodes of S. dysgalactiae subsp. equisimilis bacteremia (involving 211 patients) were available for analysis. Obesity was a statistically significant risk factor for S. dysgalactiae subsp. equisimilis bacteremia (Odds Ratio 2.96 [95% CI 2.22-3.96]). Diabetes and coronary artery disease were also associated with an increased risk of S. dysgalactiae subsp. equisimilis bacteremia (OR 4.82 [95% CI 3.62-6.42]) and (OR 3.03 [95% CI 2.18-4.19]).

CONCLUSIONS

We found obesity, diabetes, and coronary artery disease to be associated with an increased risk for S. dysgalactiae subsp. equisimilis bacteremia. These results provide an increased understanding of risk factors for S. dysgalactiae subsp. equisimilis bacteremia.

Antimicrobial resistance in beta-haemolytic streptococci in India: A four-year study

Background & objectives:

The incidence and severity of invasive and non-invasive infections demonstrate variability over time. The emerging resistance of Group A streptococci (GAS) to commonly used antibiotics is of grave concern. This study was conducted to assess the antimicrobial resistance of beta-haemolytic streptococci (βHS) in India and to ascertain the molecular mechanisms of resistance.

Methods:

All isolates of βHS from the Trauma Centre of All India Institute of Medical Sciences (AIIMS) (north India), and heavily populated area of old Delhi from 2010 to 2014 and Yashoda Hospital, Secunderabad (in south India, 2010-2012) and preserved isolates of βHS at AIIMS (2005-2009) were included. Phenotypic confirmation was done using conventional methods and the Vitek 2. Antibiotic sensitivity testing was done by disc diffusion and E-test. Detection of resistance genes, erm(A), erm(B), mef(A), tet(M) and tet(O), was done by polymerase chain reaction (PCR).

Results:

A total of 296 isolates of βHS (240 from north and 21 from south India) were included in the study. Of the 296 βHS, 220 (74%) were GAS, 52 (17.5%) were Group G streptococci and 11 (3.7%), 10 (3.3%) and three (1%) were Group B streptococci, Group C streptococci and Group F streptococci, respectively. A total of 102 (46%) and 174 (79%) isolates were resistant to tetracycline and erythromycin, respectively; a lower resistance to ciprofloxacin (21, 9.5%) was observed. A total of 42 (14%) and 30 (10%) isolates, respectively, were positive for tet(M) and erm(B) genes. Only 13 (5%) isolates were positive for mef(A). None of the isolates were positive for erm(A) and tet(O). There was discordance between the results of E-test and PCR for erythromycin and tetracycline.

Interpretation & conclusions:

A high level of resistance to erythromycin and tetracycline was seen in βHS in India. Discordance between genotypic and phenotypic results was reported. Absence of erm(A) and tet(O) with high prevalence of tet(M) and erm(B) was observed.

Emerging group C and group G streptococcal endocarditis: A Canadian perspective

OBJECTIVES

The aim of this study was to determine the incidence of infective endocarditis (IE) in patients with bacteremia caused by group C and group G streptococci (GCGS) and to characterize the burden of disease, clinical characteristics, and outcomes through a case series of patients with GCGS IE.

METHODS

Individuals with blood cultures growing GCGS in Manitoba, Canada, between January 2012 and December 2015 were included. Clinical and echocardiographic parameters were collected retrospectively. IE was suspected or confirmed according to the modified Duke criteria.

RESULTS

Two hundred and nine bacteremic events occurred in 198 patients. Transthoracic echocardiography (TTE) was performed in 33%. Suspected or confirmed IE occurred in 6% of all patients and in 18% of those with TTE. Native valve infection was more common than prosthetic valve and device-related infections (75%, 17%, and 8%, respectively). Metastatic infection was observed in 64%, primarily to the lungs (57%), skin (43%), osteoarticular system (29%), and central nervous system (29%). Sepsis occurred in 58% and streptococcal toxic shock syndrome in 50% of those with IE, with overall mortality of 17%.

CONCLUSIONS

IE from GCGS bacteremia is common and is frequently associated with severe disease, embolic events, and mortality. In the appropriate clinical context, GCGS bacteremic events should prompt investigation for IE.

Molecular characterization of invasive Streptococcus dysgalactiae subsp. equisimilis. Multicenter study: Argentina 2011-2012

Streptococcus dysgalactiae subsp. equisimilis (SDSE) has virulence factors similar to those of Streptococcus pyogenes. Therefore, it causes pharyngitis and severe infections indistinguishable from those caused by the classic pathogen. The objectives of this study were: to know the prevalence of SDSE invasive infections in Argentina, to study the genetic diversity, to determine the presence of virulence genes, to study antibiotic susceptibility and to detect antibiotic resistance genes. Conventional methods of identification were used. Antibiotic susceptibility was determined by the disk diffusion and the agar dilution methods and the E-test. Twenty eight centers from 16 Argentinean cities participated in the study. Twenty three isolates (16 group G and 7 group C) were obtained between July 1 2011 and June 30 2012. Two adult patients died (8.7%). Most of the isolates were recovered from blood (60.9%). All isolates carried speJ and ssa genes. stG62647, stG653 and stG840 were the most frequent emm types. Nineteen different PFGE patterns were detected. All isolates were susceptible to penicillin and levofloxacin, 6 (26.1%) showed resistance or reduced susceptibility to erythromycin [1 mef(A), 3 erm(TR), 1 mef(A)+erm(TR) and 1 erm(TR)+erm(B)] and 7 (30.4%) were resistant or exhibited reduced susceptibility to tetracycline [2 tet(M), 5 tet(M)+tet(O)]. The prevalence in Argentina was of at least 23 invasive infections by SDSE. A wide genetic diversity was observed. All isolates carried speJ and ssa genes. Similarly to other studies, macrolide resistance (26.1%) was mainly associated to the MLS_B phenotype.

Changing trends in β-hemolytic streptococcal bacteremia in Manitoba, Canada: 2007-2012

OBJECTIVES

European surveillance studies have reported an increasing incidence of β-hemolytic group G streptococcal bacteremia, but no studies have evaluated trends in β-hemolytic streptococcal bacteremia in North America.

METHODS

We reviewed bacteremic episodes and positive throat swab cultures from two tertiary care centers in Manitoba, Canada, from January 2007 to December 2012.

RESULTS

During the study period, 19 864 bacteremic episodes, and 9948 positive throat swabs were identified. There were 1025 (5.16%) bacteremic episodes attributable to β-hemolytic streptococci: 425 (2.03%), 339 (1.71%), 62 (0.31%), and 199 (0.95%) to β-hemolytic groups A, B, C, and G streptococci, respectively. From 2007 to 2012, there were significant increases in the proportion of bacteremia attributable to β-hemolytic streptococci in general (6.32% vs. 4.02%; p<0.0001; linear trend test, p<0.0001), and to groups G (1.49% vs. 0.43%; p<0.0001; linear trend test, p<0.0001) and C (0.58% vs. 0.13%; p=0.0068; linear trend test, p=0.0105) β-hemolytic streptococci in particular. Bacteremia attributable to groups A and B β-hemolytic streptococci and Streptococcus pneumoniae were unchanged. There were no changes in the distribution of β-hemolytic streptococcal groups among throat swabs.

CONCLUSIONS

Bacteremia attributable to β-hemolytic groups G and C streptococci increased in Manitoba, Canada. Further study of the factors underlying these changes is required.

Group C streptococcal endocarditis presenting as clinical meningitis: Report of a case and review of the literature

Lancefield group C streptococci are known to be pathogenic in a number of animal species, but cause human disease much less commonly than do streptococci of scrogroups A or B. Reported cases of bacteremic infection, pneumonia or meningitis in humans have been very severe with a grave prognosis. The authors describe a patient who presented with classic clinical and laboratory evidence of bacterial meningitis which proved to be a complication of endocarditis caused by a group C streptococcus. This is the first reported case in which meningitis was the presenting manifestation of group C streptococcal endocarditis and is only the second case in which group C streptococcal meningitis and endocarditis have been associated in the same patient. A total of 13 cases of group C streptococcal meningitis have now been reported in the medical literature. Five of these patients died, and four others recovered only to be left with neurological sequelae. The current case confirms the seriousness of group C streptococcal infections in humans. Such infections are associated with a poor prognosis despite apparently adequate antimicrobial therapy.