Risk Factors for Viridans Group Streptococcal Bacteremia in Neutropenic and Non-neutropenic Patients: A Single Center Case-Case-Control Study

Clinicomicrobiological risk factors for infective endocarditis in viridans group streptococci bacteraemia

BACKGROUND

When to perform echocardiography to rule out infective endocarditis (IE) in patients with viridans group streptococci (VGS) bloodstream infections (BSIs) is unclear.

OBJECTIVES

We aimed to identify independent risk factors for IE in patients with VGS BSI.

METHODS

This retrospective study conducted at Seoul National University Hospital from January 2013 to December 2022 involved patients with VGS and nutritionally variant streptococcal BSI, excluding single positive blood cultures and polymicrobial BSI cases. Independent risk factors were identified by multivariate logistic regression and sensitivity analyses according to echocardiography results, VGS species or the inclusion of possible IE cases.

RESULTS

Of 845 VGS BSI cases, 349 were analysed and 86 IE cases were identified (24.6%). In the multivariate analysis, heart valve disease [adjusted odds ratio (aOR), 14.14, 95% CI, 6.14-32.58; P < 0.001], persistent bacteraemia (aOR, 5.12, 95% CI, 2.03-12.94; P = 0.001), age (per year, aOR, 0.98; 95% CI, 0.96-1.00; P = 0.015), solid cancer (aOR, 0.26; 95% CI, 0.13-0.53; P < 0.001) and haematologic malignancy (aOR, 0.04; 95% CI, 0.01-0.41; P = 0.006) were independently associated with IE. Sensitivity analyses yielded consistent results; also, infection by a member of the mitis group was independent risk factor for IE (aOR, 6.50; 95% CI, 2.87-14.68; P < 0.001).

CONCLUSIONS

Younger age, heart valve disease, persistent bacteraemia, absence of underlying malignancy and BSI by a member of the mitis group were independent risk factors for IE in patients with VGS BSI. Echocardiographic evaluation could be prudently considered based on these clinicomicrobiological risk factors.

The clinical Spectrum of Viridans Group Streptococci infections in paediatric patients at a tertiary hospital

Background

Viridans Group Streptococci (VGS) are often considered organisms of low virulence; however, infection can result in clinically significant sepsis and life-threatening complications in paediatric patients.

Objectives

This study aimed to describe the spectrum of clinical presentation of VGS bacteraemia in paediatric patients, to analyse risk factors, and to describe the antibiotics resistance patterns of VGS.

Method

Cultures of VGS in paediatric patients admitted to Chris Hani Baragwanath Academic Hospital in 2019 were identified through National Health Laboratory Service. Data were extracted from archived clinical records and analysed. Sepsis scores were calculated at the time of bacteraemia.

Results

A total of 133 cultures were identified; 64 (48.1%) polymicrobial cultures and no records 4 (0.03%) were excluded; 65 (48.9%) were analysed. The median age was 1.5 months (range 0.03 to 168, interquartile range [IQR]: 0.3-13.25), 27/65 (42%) were neonates. The median duration of hospitalisation was 7 days (IQR: 3-21). The commonest diagnoses were neonatal sepsis 30.8% (n = 20) and pneumonia 28% (n = 18). The systemic inflammatory response syndrome (SIRS) score was ≥ 2 in 57% (16/28) patients; paediatric sequential organ failure assessment (pSOFA) score was > 2 in 10/24 (42%). Fifty-seven (88%) patients were discharged; three (5%) required ICU admission and 8/65 (12.3%) died. Malnutrition was present in 50% of patients who died. Cephalosporins and penicillin had sensitivity of 89% and 55%, respectively.

Conclusion

Viridans Group Streptococci bacteraemia was common in neonates, and pneumonia was a common presentation in this cohort. The VGS bacteraemia was associated with morbidity and deaths in this cohort.

Contribution

The VGS should be considered a significant organism when cultured from sterile sites and routine antibiotic susceptibility testing should be performed. Prospective studies are recommended.

Streptococcus mitis as a New Emerging Pathogen in Pediatric Age: Case Report and Systematic Review

Streptococcus mitis, a normal inhabitant of the oral cavity, is a member of Viridans Group Streptococci (VGS). Generally recognized as a causative agent of invasive diseases in immunocompromised patients, S. mitis is considered to have low pathogenic potential in immunocompetent individuals. We present a rare case of sinusitis complicated by meningitis and cerebral sino-venous thrombosis (CSVT) caused by S. mitis in a previously healthy 12-year-old boy with poor oral health status. With the aim of understanding the real pathogenic role of this microorganism, an extensive review of the literature about invasive diseases due to S. mitis in pediatric patients was performed. Our data define the critical role of this microorganism in invasive infections, especially in immunocompetent children and in the presence of apparently harmful conditions such as sinusitis and caries. Attention should be paid to the choice of therapy because of VGS's emerging antimicrobial resistance patterns.

Outcomes of neutropenic hemato-oncological patients with viridans group streptococci (VGS) bloodstream infection based on penicillin susceptibility

Viridans group streptococci (VGS) bloodstream infection (BSI) in neutropenic patients can be a severe complication. A higher prevalence of vancomycin use has been reported due to reduced susceptibility to penicillin. We aimed to assess the impact on mortality of both penicillin minimal inhibitory concentration (MIC) and the use of vancomycin. We conducted a retrospective multicenter study including consecutive neutropenic patients with VGS BSI between 2007 and 2019. Univariable and multivariable analyses were conducted to evaluate risk factors for mortality, including penicillin susceptibility as an independent variable. Non-susceptibility to penicillin was defined as MIC ≥ 0.25. We included 125 neutropenic patients with VGS BSI. Mean age was 53 years and ~ 50% were women. Overall, 30-day mortality rate was 25/125 (20%), and 41 patients (33%) had a VGS isolate non-susceptible to penicillin. In univariable analysis, no significant association was demonstrated between penicillin non-susceptibility and mortality (9/25, 26% vs. 32/100, 32%, p = 0.81). Among patients with a non-susceptible strain, the use of vancomycin was not significantly associated with mortality (empirical, p = 0.103, or definitive therapy, p = 0.491). Factors significantly associated with increased mortality in multivariable analysis included functional status (ECOG > 1, adjusted odds ratio [aOR] 12.53, 95% CI 3.64-43.14; p < 0.0001); allogeneic transplantation (aOR 6.33, 95% CI 1.96-20.46; p = 0.002); and co-pathogen in blood cultures (aOR 3.99, 95% CI 1.34-11.89; p = 0.013). Among neutropenic hemato-oncological patients with VGS BSI, penicillin non-susceptibility and the use of vancomycin were not associated with mortality. Thus, vancomycin should not be used routinely as empirical therapy in neutropenic patients with suspected VGS BSI.

Infections in Hospitalized Cancer Patients

Cancer patients are at an increased risk of developing infections that are primarily treatment-driven but may also be malignancy-driven. While cancer treatments such as chemotherapy, radiotherapy, and surgery have been known to improve malignancy morbidity and mortality, they also have the potential to weaken immune defenses and induce periods of severe cytopenia. These adverse effects pave the way for opportunistic infections to complicate a hospitalized cancer patient's clinical course. Understanding the risk each patient inherently has for developing a bacterial, fungal, or viral infection is critical to choosing the correct prophylactic treatment in conjunction with their scheduled cancer therapy. This review discusses the most common types of infections found in hospitalized cancer patients as well as the current guidelines for prophylactic and antimicrobial treatment in cancer patients. In addition, it describes the interaction between antibiotics and cancer therapies for consideration when treating infection in a cancer patient.

Clinical Outcomes of Ceftriaxone vs Penicillin G for Complicated Viridans Group Streptococci Bacteremia

Background

Ceftriaxone (CTX) and penicillin G (PCN G) are considered reasonable treatment options for viridans group streptococci (VGS) bloodstream infections, but comparisons between these agents are limited. We evaluated clinical outcomes among patients treated with these agents for complicated VGS bacteremia.

Methods

This was a single-center retrospective study of adult patients with ≥1 positive VGS blood culture who were treated with either CTX or PCN G/ampicillin (both included in the PCN arm) between January 2013 and June 2019. The primary outcome was a composite of safety end points, including hospital readmission due to VGS bacteremia or adverse events (AEs) from therapy, Clostridioides difficile infections, treatment modification or discontinuation due to AEs from therapy, and development of extended-spectrum beta-lactamase resistance. Secondary outcomes included individual safety end points, VGS bacteremia recurrence, hospital readmission, and all-cause mortality.

Results

Of 328 patients screened, 94 met eligibility criteria (CTX n = 64, PCN n = 30). Streptococcus mitis was the most common isolate, and infective endocarditis was the predominant source of infection. CTX was not significantly associated with increased risk of the primary composite safety outcome (CTX 14% vs PCN 27%; P = .139). The driver of the composite outcome was hospital readmission due to VGS bacteremia or therapy complications. No secondary end points differed significantly between groups. On multivariate analysis, source removal was a protective factor of the primary composite safety outcome.

Conclusions

Despite potential safety concerns with the prolonged use of CTX in complicated VGS bacteremia, this study did not demonstrate higher rates of treatment failure, adverse events, or resistance.

Diagnóstico de carcinoma urotelial durante estudio de bacteremia por Streptococcus gordonii

La bacteremia por Streptococcus gordonii es infrecuente. Su aislamiento en hemocultivo traduce alta significancia clínica y debe dirigir el abordaje diagnóstico hacia la búsqueda de entidades subyacentes como neoplasias hematológicas, cardiopatías valvulares, neumonía, alteraciones estructurales de cabeza y cuello, inmunosupresión, y otras condiciones asociadas. No se han identificado reportes en pacientes con neoplasia de vías urinarias como posible condicionante de bacteremia por este agente. Se describe el caso de un paciente que, durante el estudio de bacteremia por este microorganismo, fue diagnosticado de carcinoma urotelial de alto grado.