Streptococcus gallolyticus bacteremia detected in apheresis platelets and its link to colonic neoplasms

Introduction: Streptococcus gallolyticus belongs to theStreptococcus bovis complex, and it is a common bacterium colonizing the gastrointestinal tract. Its presence in the blood may suggest an underlying pathology such as a colonic neoplasm. We report herein a case of S. bovis bacteremia in an apheresis platelet donor, review similar cases in the literature, and suggest a flowchart for the management of similar cases in other blood donation centers. Case Presentation: A 61-year-old subject presented to a Hemotherapy Service to make an apheresis platelet donation. On quality control testing, S. gallolyticus was identified in hemoculture, and the donor was called back for follow-up. At first, a new hemoculture was requested, and the patient was referred to the outpatient department of infectious diseases to further investigate pathologies associated with S. gallolyticus. A subsequent colonoscopy investigation evidenced a polypoid structure in the ascending colon. Pathology reported the resected specimen as a low-grade tubular adenoma. Conclusion: Isolation of S. bovis in blood products requires further investigation and should be managed with precision by Hemotherapy Services. A standard protocol for the management of asymptomatic patients with S. bovis positive hemoculture, with the requests of a new blood culture, a colonoscopy, and an echocardiogram is crucial, as it may ensure early diagnosis and reduce morbidity and mortality. (AU)

Streptococcus gallolyticus - A potentially neglected pathogen causing neonatal sepsis not covered by routine group B streptococcus screening.

We report 4 cases of neonatal sepsis caused by Streptococcus gallolyticus. The clinical course was quite similar to early-and late-onset group B streptococcus disease. None of the mothers had group B streptococcus (GBS) colonization on prenatal screening nor received intrapartum antibiotics. We proposed the sporadic distribution of S. gallolyticus sepsis among neonates was partly due to relatively low colonization rate in adults compared with GBS. Species determination of S. gallolyticus may not be available using conventional microbiological methods and may contribute to underestimation or misclassification. In our series, we highlighted the importance of S. gallolyticus as an important pathogen in neonatal sepsis deserving further surveillance.

Detection of Streptococcus gallolyticus in colorectal cancer and inflammatory bowel disease patients compared to control group in southwest of Iran.

There are several pieces of evidence regarding the role of bacteria, such as Streptococcus bovis/gallolyticus in the etiology of gastrointestinal diseases such as colorectal cancer (CRC) and inflammatory bowel disease (IBD). Therefore, the aim of this study was to detect S. gallolyticus subsp. gallolyticus (Sgg) in fecal samples of CRC and IBD patients by culture and molecular methods, in Ahvaz, southwest of Iran. A total of 106 fecal samples were collected from 22 CRC patients, 44 IBD patients, and 40 healthy individuals. The prevalence of Sgg was investigated by culture and polymerase chain reaction (PCR) with specific primers for sodA gene. The results of the stool culture showed that the overall prevalence of Sgg was 9 (13.6%) out of 66 patients. Meanwhile, the number of Sgg isolated from IBD and CRC patients was 7 (15.9%) and 2 (9%), respectively. The bacteria were not isolated from any of the control groups. On the basis of PCR, S. gallolyticus was detected in 24 (36.4%) out of 66 patients. Meanwhile, the number of IBD patients with positive sodA gene was 15 (34.1%) out of 44 cases. In CRC patients, the sodA gene was detected in 9 (40.9%) of 22 cases. Two (5%) of the specimens in the control group had the sodA gene. According to our results, S. gallolyticus subsp. gallolyticus might be involved in CRC and IBD pathogenesis. More investigation with different samples in the various areas might be shaded light on these results.

Central retinal artery occlusion from Streptococcus gallolyticus endocarditis.

Central retinal artery occlusion (CRAO) is a rare but blinding disorder. We present a case of a 81-year-old woman with multiple cardiovascular comorbidities admitted to the emergency department due to sudden, painless vision loss on left eye (oculus sinister (OS)) on awakening. The patient also reported long standing fatigue associated with effort that started 4 months before admission. She presented best corrected visual acuity of counting fingers OS. Funduscopy OS revealed macular oedema with cherry red spot pattern. Blood cultures came positive for Streptococcus gallolyticus in the context of a bacteremia and native mitral valve vegetation identified on transoesophageal echocardiography. CRAO of embolic origin was admitted in the context of an infective endocarditis. CRAO can be the first manifestation of a potentially fatal systemic condition and thus multidisciplinary approach is warranted with close collaboration between ophthalmologists and internists in order to provide proper management and the best possible treatment.

Traditional milk transformation schemes in Côte d'Ivoire and their impact on the prevalence of Streptococcus bovis complex bacteria in dairy products.

The Streptococcus bovis/Streptococcus equinus complex (SBSEC) and possibly Streptococcus infantarius subsp. infantarius (Sii) are associated with human and animal diseases. Sii predominate in spontaneously fermented milk products with unknown public health effects. Sii/SBSEC prevalence data from West Africa in correlation with milk transformation practices are limited. Northern Côte d'Ivoire served as study area due to its importance in milk production and consumption and to link a wider Sudano-Sahelian pastoral zone of cross-border trade. We aimed to describe the cow milk value chain and determine Sii/SBSEC prevalence with a cross-sectional study. Dairy production practices were described as non-compliant with basic hygiene standards. The system is influenced by secular sociocultural practices and environmental conditions affecting product properties. Phenotypic and molecular analyses identified SBSEC in 27/43 (62.8%) fermented and 26/67 (38.8%) unfermented milk samples. Stratified by collection stage, fermented milk at producer and vendor levels featured highest SBSEC prevalence of 71.4% and 63.6%, respectively. Sii with 62.8% and 38.8% as well as Streptococcus gallolyticus subsp. macedonicus with 7.0% and 7.5% were the predominant SBSEC species identified among fermented and unfermented milk samples, respectively. The population structure of Sii/SBSEC isolates seems to reflect evolving novel dairy-adapted, non-adapted and potentially pathogenic lineages. Northern Côte d'Ivoire was confirmed as area with high Sii presence in dairy products. The observed production practices and the high diversity of Sii/SBSEC supports in-depth investigations on Sii ecology niche, product safety and related technology in the dairy value chain potentially affecting large population groups across sub-Saharan Africa.

Gangrenous gas necrosis of the spleen: a case report.

BACKGROUND: Splenic abscess usually arises from hematogenous spread. Causative pathogens are various and anaerobic pathogens are rarely reported. CASE PRESENTATION: We report the case of a 50-year-old male patient who was admitted for sepsis due to gangrenous necrosis of the spleen associated with bacteremia. Causative pathogens were Clostridium perfringens and Streptococcus gallolyticus. The patient was successfully treated by splenectomy and targeted intravenous antibiotics. No underlying or predisposing disease was found. CONCLUSION: Gangrenous necrosis of the spleen is a rare entity that can be successfully treated by splenectomy and antibiotics.

Microbiological and clinical characteristics of Streptococcus gallolyticus subsp. pasteurianus infection in China.

BACKGROUND: Infections by Streptococcus gallolyticus subsp. pasteurianus (SGSP) is often underestimated. Herein, the epidemiological features and resistant characteristics of SGSP in mainland China are characterized to enable a better understanding of its role in clinical infections. METHODS: In the present work, 45 SGSP isolates were collected from the samples of bloodstream, urine, aseptic body fluid, and fetal membrane/placenta from patients in 8 tertiary general hospitals of 6 cities/provinces in China from 2011 to 2017. The identification of all isolates was performed using traditional biochemical methods, 16S rRNA and gyrB sequencing, followed by the characterization of their antibiotic resistance profiling and involved genes. RESULTS: Among 34 non-pregnancy-related patients, 4 (4/34,11.8%) patients had gastrointestinal cancer, 10 (10/34, 29.4%) patients had diabetes, and one patient had infective endocarditis. Moreover, 11 cases of pregnant women were associated with intrauterine infection (9/11, 81.2%) and urinary tract infection (1/11, 9.1%), respectively. Except one, all other SGSP isolates were correctly identified by the BD Phoenix automated system. We found that all SGSP isolates were phenotypically susceptible to penicillin, ampicillin, cefotaxime, meropenem, and vancomycin. Forty strains (40/45, 88.9%) were both erythromycin and clindamycin-resistant, belonging to the cMLSB phenotype, and the majority of them carried erm(B) gene (39/40, 97.5%). Although the cMLSB/erm(B) constituted the most frequently identified phenotype/genotype combination (25/40, 62.5%) among all erythromycin-resistant cMLSB isolates, erm(B)/erm(A), erm(B)/mef(A/E), and erm(B)/erm(T) was detected in 7, 4, and 3 isolates, respectively. Furthermore, 43 strains (43/45, 95.6%) were tetracycline-resistant, and out of these, 39 strains (39/45, 86.7%) carried tet(L), 27(27/45, 60.0%) strains carried tet(O), and 7 (7/45, 15.6%) strains carried tet(M), alone or combined, respectively. All erythromycin-resistant isolates were also resistant to tetracycline. CONCLUSIONS: It is important to study and draw attention on SGSP, an underreported opportunistic pathogen targeting immunodeficient populations, notably elderly subjects, pregnant women and neonates.

Analysis of Fusobacterium nucleatum and Streptococcus gallolyticus in saliva of colorectal cancer patients.

Aim: The aim of the study was to examine the prevalence and amount of Fusobacterium nucleatum (Fn), Porphyromonas gingivalis (Pg) and Streptococcus gallolyticus (Sg) in the saliva of colorectal cancer (CRC) patients and controls. Methods: PCR analyses performed in 71 CRC patients and 77 controls. Results: Saliva samples of patients had higher amounts of Fn (p = 0.001) and Sg (p < 0.001) compared with controls. Amount of Fn and Sg were lower in the microsatellite instability (+) group. Evaluation of salivary Sg amount by receiver operating characteristics analysis found to have diagnostic value for CRC (AUC: 0.84, 95% CI: 0.72-0.96). Conclusion: We found higher amounts of Fn and Sg in the saliva of CRC patients. Salivary Sg could helpful in distinction of CRC.

Streptococcus Gallolyticus endocarditis in patient with liver cirrhosis: a case report.

Streptococcus gallolyticus (S. gallolyticus) bacteremia is commonly associated with endocarditis and diseases of gastrointestinal tract, especially with colorectal carcinoma. On the other side, it is rarely connected to liver disease, especially alcoholic liver disease. A 44-old patient with a history of one month fever, pre-existing heart murmur and previous alcohol abuse, was treated in Clinic for Infectious and tropical diseases, Clinical Centre of Serbia (CCS), Belgrade. The diagnose of infective endocarditis (IE) of the aortic valve caused by S. gallolyticus has been established. Despite the conducted antibiotic treatment based on antibiogram, pericardial effusion with paracardial aortic abscess was diagnosed on the 9th day of treatment. Pericardiocentesis was done and 800 mL of haemorrhagic fluid was evacuated in the Clinic for Cardiology, CCS. Unfortunately, 20th day of hospitalization the patient died. Clinical autopsy confirmed endocarditis, liver cirrhosis and chronic pericarditis. Prognosis of the outcome of treatment of patient with endocarditis caused S. gallolyticus and liver cirrhosis is not optimistic. Therefore, significant attention should be given to patients with liver cirrhosis and febrile of unknown origin.

Novel association of Streptococcus gallolyticus subspecies pasteurianus and hepatocelluar carcinoma: opening new frontiers.

BACKGROUND: Streptococcus gallolyticus subsp. gallolyticus bacteremia is associated with colorectal malignancies. There is limited data regarding the association of Streptococcus gallolyticus subsp. pasteurianus with malignancies. We aimed to study the pattern of isolation of Streptococcus gallolyticus and analysis of risk factors in patients with hepatobiliary diseases. We also planned to evaluate its association with hepatocellular malignancy. METHODS: We analyzed clinical and laboratory data of 68 cases of Streptococcus gallolyticus infections (77 isolates) from January 2013 to December 2017. These included blood (58), ascitic fluid (15), bile (2) and pleural fluid (2). We analyzed the risk factors in patients developing malignancy with Streptococcus gallolyticus infections. RESULTS: Amongst the 68 patients studied, eight (11.76%) had confirmed malignancies, hepatocellular carcinoma (HCC) (5), rectal adenocarcinoma (1), pancreatic carcinoma (1) and uterine tumors (1). Simultaneous isolation of S. gallolyticus subsp. pasteurianus from blood and ascitic fluid in eight patients (11.8%, p = .01) was significantly associated with the occurrence of HCC. Streptococcus gallolyticus infection with HCC was associated with younger age (median 55 years), lymphocytosis and elevated gamma-glutamyl transferase (GGT). CONCLUSIONS: This study provides a novel insight into the association of Streptococcus gallolyticus subspecies pasteurianus with HCC. The isolation of the organism from blood and ascitic fluid should prompt the clinicians to search for evidence of HCC actively.

Association Between Bacteremia From Specific Microbes and Subsequent Diagnosis of Colorectal Cancer.

BACKGROUND & AIMS: Colorectal cancer (CRC) development has been associated with increased proportions of Bacteroides fragilis and certain Streptococcus, Fusobacterium, and Peptostreptococcus species in the intestinal microbiota. We investigated associations between bacteremia from specific intestinal microbes and occurrence of CRC. METHODS: We performed a retrospective study after collecting data on 13,096 adult patients (exposed group) in Hong Kong hospitalized with bacteremia (identified by blood culture test) without a previous diagnosis of cancer from January 1, 2006 through December 31, 2015. We collected data on intestinal microbes previously associated with CRC (genera Bacteroides, Clostridium, Filifactor, Fusobacterium, Gemella, Granulicatella, Parvimonas, Peptostreptococcus, Prevotella, Solobacterium, and Streptococcus). Clinical information, including patient demographics, comorbid medical conditions, date of bacteremia, and bacterial species identified, were collected. The incidence of biopsy-proved CRC was compared between the exposed and unexposed (patients without bacteremia matched for age, sex, and comorbidities) groups. RESULTS: The risk of CRC was increased in patients with bacteremia from B fragilis (hazard ratio [HR] = 3.85, 95% CI = 2.62-5.64, P = 5.5 × 10-12) or Streptococcus gallolyticus (HR = 5.73, 95% CI = 2.18-15.1, P = 4.1 × 10-4) compared with the unexposed group. In addition, the risk of CRC was increased in patients with bacteremia from Fusobacterium nucleatum (HR = 6.89, 95% CI = 1.70-27.9, P = .007), Peptostreptococcus species (HR = 3.06, 95% CI = 1.47-6.35, P = .003), Clostridium septicum (HR = 17.1, 95% CI = 1.82-160, P = .013), Clostridium perfringens (HR = 2.29, 95% CI = 1.16-4.52, P = .017), or Gemella morbillorum (HR = 15.2, 95% CI = 1.54-150, P = .020). We observed no increased risk in patients with bacteremia caused by microbes not previously associated with colorectal neoplasms. CONCLUSIONS: In a retrospective analysis of patients hospitalized for bacteremia, we associated later diagnosis of CRC with B fragilis and S gallolyticus and other intestinal microbes. These bacteria might have entered the bloodstream from intestinal dysbiosis and perturbed barrier function. These findings support a model in which specific members of the intestinal microbiota promote colorectal carcinogenesis. Clinicians should evaluate patients with bacteremia from these species for neoplastic lesions in the colorectum.

Streptococcus gallolyticus subsp. pasteurianus meningitis complicated by venous sinus thrombosis: A case report.

A case of Streptococcus gallolyticus subsp. pasteurianus meningitis, unusually occurring in a splenectomized patient and complicated by cerebral venous thrombosis, is described. Following presentation with meningism and diagnosis and management of S. gallolyticus meningitis, the patient presented again with a further 4days of fevers and subsequently developed left-sided paresthesias. Cerebral imaging revealed a venous thrombus in the right frontal cortical veins and left sigmoid sinus. The patient recovered following 4 weeks of intravenous ceftriaxone and anticoagulation with enoxaparin and then warfarin. Apart from the splenectomy, no underlying cause was found. The patient was commenced on life-long prophylactic amoxicillin, given appropriate vaccinations, and anticoagulated with warfarin. After initial difficulties, identification of the causative organism to the subspecies level was confirmed by analysis of short-read whole genome sequencing data. This case demonstrates two features that have not previously been reported for S. gallolyticus subsp. pasteurianus infections: splenectomy as a potential risk factor and that infection may be complicated by cerebral venous thrombosis. The resolution provided by whole genome sequencing was valuable in accurately identifying the bacterial subspecies.

Novel Tn916-like elements confer aminoglycoside/macrolide co-resistance in clinical isolates of Streptococcus gallolyticus ssp. gallolyticus.

Background: Streptococcus gallolyticus ssp. gallolyticus (Sgg) is a commensal bacterium and an opportunistic pathogen. In humans it has been clinically associated with the incidence of colorectal cancer (CRC) and epidemiologically recognized as an emerging cause of infective endocarditis (IE). The standard therapy of Sgg includes the administration of a penicillin in combination with an aminoglycoside. Even though penicillin-resistant isolates have still not been reported, epidemiological studies have shown that this microbe is a reservoir of multiple acquired genes, conferring resistance to tetracyclines, aminoglycosides, macrolides and glycopeptides. However, the underlying antibiotic resistance mobilome of Sgg remains poorly understood. Objectives: To investigate the mobile genetic basis of antibiotic resistance in multiresistant clinical Sgg. Methods: Isolate NTS31106099 was recovered from a patient with IE and CRC at Nantes University Hospital, France and studied by Illumina WGS and comparative genomics. Molecular epidemiology of the identified mobile element(s) was performed using antibiotic susceptibility testing (AST), PCR, PFGE and WGS. Mobility was investigated by PCR and filter mating. Results: Two novel conjugative transposons, Tn6263 and Tn6331, confer aminoglycoside/macrolide co-resistance in clinical Sgg. They display classical family Tn916/Tn1545 modular architecture and harbour an aph(3')-III→sat4→ant(6)-Ia→erm(B) multiresistance gene cluster, related to pRE25 of Enterococcus faecium. These and/or closely related elements are highly prevalent among genetically heterogeneous clinical isolates of Sgg. Conclusions: Previously unknown Tn916-like mobile genetic elements conferring aminoglycoside/macrolide co-resistance make Sgg, collectively with other gut Firmicutes such as enterococci and eubacteria, a potential laterally active reservoir of these antibiotic resistance determinants among the mammalian gastrointestinal microbiota.

Laboratory Diagnosis of Infective Endocarditis.

Infective endocarditis is life-threatening; identification of the underlying etiology informs optimized individual patient management. Changing epidemiology, advances in blood culture techniques, and new diagnostics guide the application of laboratory testing for diagnosis of endocarditis. Blood cultures remain the standard test for microbial diagnosis, with directed serological testing (i.e., Q fever serology, Bartonella serology) in culture-negative cases. Histopathology and molecular diagnostics (e.g., 16S rRNA gene PCR/sequencing, Tropheryma whipplei PCR) may be applied to resected valves to aid in diagnosis. Herein, we summarize recent knowledge in this area and propose a microbiologic and pathological algorithm for endocarditis diagnosis.

Necroptosis of Splenic Macrophages Induced by Streptococcus gallolyticus subsp. pasteurianus.

A previous study demonstrated that a highly virulent strain of Streptococcus gallolyticus subsp. pasteurianus, designated as the AL101002 strain, induced high mortality in ducklings with splenic lesions. In this study, 42 ducklings were subcutaneously inoculated with the AL101002 strain to study changes in splenic lesions over time. The spleens from these ducklings were significantly enlarged by congestion and edema, and/or showed multiple marbled areas 14 days postinoculation (dpi). The AL101002 strain was reisolated from the spleens and blood and confirmed by immunohistochemistry (IHC) with the use of anti-AL101002 antibody. Histopathologically, the main lesion was macrophage necrosis in the spleens from 1 to 7 dpi. Terminal dUTP nick-end labeling assay, transmission electron microscopy, and IHC by anti-macrosialin antibody (CD68) demonstrated that macrophage necrosis was necroptosis, which was further confirmed by quantitative (real-time) reverse-transcriptase PCR analysis. Two major factors of apoptosis, caspase 3 and caspase 8, did not significantly change during the AL101002 infection, suggesting that apoptosis signals were not activated. However, the key factor mixed lineage kinase like was increased significantly (P < 0.05) from Day 1 to Day 14 dpi. Inflammatory cytokine interleukin-1ß and interleukin-6 had significantly (P < 0.01) upregulated expression in the spleens on Day 1 dpi. Tumor necrosis factor α was downregulated from Day 1 to Day 5 dpi, but increased from Day 7 to Day 14. Our results demonstrated that AL101002 strain mainly infects macrophages and resulted in macrophage necroptosis and suggested that macrophage necroptosis in spleens is involved in the pathogenesis of S. gallolyticus subsp. pasteurianus infection in ducklings.

Identification, antimicrobial resistance and molecular characterization of the human emerging pathogen Streptococcus gallolyticus subsp. pasteurianus.

This study aimed to retrospectively identify 22Streptococcus bovis clinical strains based on the new taxonomy, as well as to investigate their antibiotic-resistance and clonality. Strains were identified by Phoenix100 system, 16S rRNA sequencing, and two MALDI-TOF MS platforms (Bruker Biotyper, Vitek MS). Antibiotic resistance was determined both phenotypically and genotypically, and clonality was assessed by PFGE. Most of strains (63.6%) were isolated from urine, and diabetes was the most common underlying disease (31.8%). Phoenix100 system revealed all strains belonged to biotype II, and 16S rRNA sequencing identified all strains as S. gallolyticus subsp pasteurianus (SGSP). Although both MALDI-TOF MS systems correctly identified isolates to the species level, only Bruker Biotyper accurately identified to the subspecies level. Erythromycin-resistant strains (31.8%) were also clindamycin-resistant and positive for erm(B). Strains resistant to tetracycline (68.2%) were also resistant to erythromycin. PFGE showed high genetic variability identifying 17 different pulsotypes, most of which single.

Inducible Expression of both ermB and ermT Conferred High Macrolide Resistance in Streptococcus gallolyticus subsp. pasteurianus Isolates in China.

Streptococcus gallolyticus subsp. pasteurianus is an under-recognized pathogen and zoonotic agent causing opportunistic infections in humans. Despite increasing recognition of this subspecies as a cause for human infectious diseases, limited information is known about its antibiotic resistance mechanism. In this study, we aim to identify the molecular mechanism underlying the high macrolide resistance of six S. gallolyticus subsp. pasteurianus isolates from dead ducklings collected in several natural outbreaks in China during 2010-2013. All isolates exhibited multi-drug resistance including high macrolide resistance (MIC ≥ 1024 mg/L for erythromycin, and 512 mg/L for clarithromycin). Efflux-encoding mefA and mefE genes were not detectable in these isolates. The presence of 23S rRNA mutations in specific isolates did not significantly change macrolide MICs. No nucleotide substitutions were found in genes encoding ribosomal proteins L4 or L22. The ermB and ermT genes were found in the genomes of all isolates. These two genes were acquired independently in one highly virulent isolate AL101002, and clustered with Tn916 and IS1216, respectively. The expression of both ermB and ermT in all isolates was erythromycin inducible and yielded comparable macrolide MICs in all six isolates. Taken together, inducible expression of both ermB and ermT conferred high macrolide resistance in these S. gallolyticus subsp. pasterianus isolates. Our findings reveal new macrolide resistance features in S. gallolyticus subsp. pasteurianus by both ermB and ermT.