Streptococcus dysgalactiae subsp. equisimilis possessing Lancefield's group A antigen

We isolated Streptococcus dysgalactiae subsp. equisimilis with Lancefield's group A antigen from a patient in Osaka City. This clinical isolate formed beta-hemolytic large colonies on sheep blood agar, and was catalase-negative gram-positive cocci carrying Lancefield's group A antigen. Therefore, Streptococcus pyogenes and this clinical isolate could not be classified by the conventional method on the basis of Lancefield's group antigen. In addition, the rapid detection system of group A streptococci based on group A antigen detection techniques could not divide into two species. Recently, S. dysgalactiae subsp. equisimilis with Lancefield's group G antigen has been isolated from severe invasive streptococcal infection in an increasing frequency in Japan. A possibility that group A S. dysgalactiae subsp. equisimilis cause a serious infection from now on cannot be denied. Thus the discrimination of S. pyogenes from group A S. dysgalactiae subsp. equisimilis is very important. To identify beta-hemolytic streptococci, it is necessary to consider a serogrouping test as one of characteristics of streptococci, and to identify by checking biochemical tests like the PYR test.     

A case of severe necrotizing cellulitis caused by group G Streptococcus dysgalactiae subsp. equisimilis

Group G streptococcus (GGS) is infrequently associated with severe invasive soft tissue infection and toxic shock syndrome. A 74-year-old woman with a history of lymphedema of the lower extremities after surgical and radiation therapy for uterine cancer and diabetic mellitus and admitted for swelling of the right leg, fever, and dyspnea. She presented with shock and necrotizing cellulitis of the right lower extremity. Laboratory tests showed leukocytepenia, acute renal and liver dysfunction, and muscle damage. She rapidly developed multiple organ failure and necrotizing cellulitis. A swab from skin vesicle, throat, and blood culture grew Group G Streptococcus dysgalactiae subsp. equisimilis. Despite endotoxin hemoadsorption therapy, administration of antibiotics, and intravenous immunoglobulin, she died 9 days after admission due to toxic shock syndrome caused by GGS. The M-protein gene (emm) typing of GGS isolated from both blood and skin lesion showed stG 485.0. Three virulence genes, sagA, slo and skcg, were detected from GGS isolated from them.     

A case of thoracic empyema with gas formation associated with Streptococcus dysgalactiae subsp. equisimilis

A 63-year-old woman suffering from dyspnea since 1 week earlier underwent a combination therapy of oral corticosteroid and ciclosporin for rheumatic arthritis. Chest radiography showed plural effusion with gas formation in the right thorax. Empyema was diagnosed based on the specimen from pleural effusion. After a chest tube was emplaced to remove and wash out pus, antibiotics were started and empyema improved immediately. Streptococcus dysgalactiae subsp. equisimilis, but not aerobic bacilli, was detected from the pus by repeated culture. Insofar as we know this is the first case of empyema with gas formation associated with Streptococcus dysgalactiae subsp. equisimilis.     

24株停乳链球菌似马亚种的分子鉴定和基因分型

目的 探讨停乳链球菌似马亚种(Streptococcus dysgalactiae subspecies equisimilis,SDSE)感染的临床分布特点及分子特征。方法 收集SDSE感染患者的临床资料及相应分离菌株,分离株经全自动微生物分析系统、基质辅助激光解析电离飞行时间质谱技术(MALDI-TOF-MS)及PCR扩增16S rRNA和链激酶前体基因等3种方-法进行鉴定。对SDSE菌株进行M蛋白基因(emm)分型和多位点序列分型(Multilocus sequence typing, MLST),并通过BioNumerics 6.6软件进行聚类分析。结果 24株停乳链球菌似马亚种主要分离自咽拭子、皮肤、血液,分别占58.33%、20.83%、8.33%;24株SDSE被分为5种emm类型,以stCNSRT2.0(n=16,66.7%)占优势,其次是stG840.0(n=3,12.5%)。通过MLST分型,共有6种ST型别,以ST44(n=17,70.8%)为主,ST605为新定义的ST型。结论 本研究中SDSE分离株具有分子多样性,ST605为首次报告的MLST型别。     

A case of acute septic osteomyelitis onset due to Streptococcus dysgalactiae subsp. equisimilis in an elderly diabetic patient

Group C streptococci are increasingly causing invasive infections such as that we report here. A 70-year-old man being treated for diabetes and seen at the emergency room for neck pain and fever was hospitalized for possible sepsis. His temperature was 39.8 degrees C, regular pulse 101 bpm, and pain reinforced in flexing and cervical rotation. Streptococcus dysgalactiae subsp. equisimilis (SDSE) was cultured from blood. Neck pain gradually decreased with of 2 million units PCG 6 times/day. Magnetic resonance imaging (MRI) of the cervical spine showed high-intensity areas in fat-suppression imaging at C7, Thl and intervertebral disks plus enhancement around the vertebral body, yielding a diagnosis of cervicothoracic vertebral osteomyelitis. Antimicrobial intravenous therapy continuede 6 weeks. The man was discharged after 45 days without relapse.     

A case of bacterial pneumonia caused by Streptococcus dysgalactiae subsp. equisimilis, showing patchy consolidations resembling organizing pneumonia]

In December, 2001, a 67-year-old woman was given a diagnosis of having systemic sclerosis and organizing pneumonia. Steroid treatment improved her condition, and she received no further medication for approximately three years thereafter. In October 2005, she visited Kurume University Hospital because of cough and fever. Chest X-ray film and high-resolution computed tomography (HRCT) showed bilateral patchy consolidation with air-bronchogram sign and ground-glass opacities, predominantly in the right lower lung field, suggesting relapse of organizing pneumonia. However, bronchoalveolar lavage fluid (BALF) analysis showed an increase of neutrophils (79%) and the CD4/CD8 ratio (4.04). Streptococcus dysgalactiae subsp. equisimilis (beta-hemolytic, Lancefield group G) was detected by bacterial culture of the BALF. Treatment with sulbactam sodium/ampicillin sodium (SBT/ ABPC) rapidly improved her symptoms. The patchy consolidations on chest X-ray and HRCT also disappeared after the treatment. On the basis of these clinical and bacteriological findings, we diagnosed the patient as having bacterial pneumonia caused by Streptococcus dysgalactiae subsp. equisimilis.     

Intrinsic reduced susceptibility of serotype 6 Streptococcus pyogenes to fluoroquinolone antibiotics

BACKGROUND: Fluoroquinolone resistance is common in Staphylococcus aureus, is increasing in Streptococcus pneumoniae, and is reported in Streptococcus pyogenes. METHODS: We surveyed 384 clinical isolates of S. pyogenes, isolated during 2002-2003, for susceptibility to ciprofloxacin. We performed nucleotide sequencing of the parC and gyrA genes and determined the M/emm type for selected isolates. Additionally, we analyzed M/emm type 6 S. pyogenes isolated during 1918-2003 from diverse locations. RESULTS: Of the survey isolates, 10.9% had reduced zones of inhibition to ciprofloxacin in the disk-diffusion test and had elevated minimum inhibitory concentrations to other fluoroquinolones, compared with those of fully susceptible isolates. Of the resistant isolates, 90.5% were M/emm type 6, and all sequenced M/emm type 6 isolates contained a serine-to-alanine substitution at position 79 in parC. Strikingly, the same findings were also present in macrolide-resistant isolates from a recent outbreak of S. pyogenes infection in Pittsburgh and in the Lancefield reference strain of M type 6, which was isolated in 1918, decades before the development of fluoroquinolone antibiotics. CONCLUSION: M/emm type 6 S. pyogenes has intrinsic reduced susceptibility to fluoroquinolones, as a result of a polymorphism in parC. This finding was also demonstrated in erythromycin-resistant M/emm type 6 S. pyogenes, which raises concern for the emergence of multidrug-resistant S. pyogenes.     

In vitro susceptibility of Streptococcus agalactiae clinical isolates to beta-lactam antibiotics

The susceptibility of Streptococcus agalactiae (S. agalactiae) clinical isolates of Juntendo University Urayasu Hospital, and type strain ATCC 13813 to beta-lactam antimicrobial agents was evaluated by means of macro-broth dilution MIC determination, killing kinetics and population analysis. When 10(6) cells of S. agalactiae were inoculated and cultured in Todd-Hewitt broth containing two-fold serial dilutions of penicillin, the viable cell count showed that about 10(2) cells survived irrespective of the penicillin concentration which ranged from 0.063 to 128 micrograms/ml. The result indicated that S. agalactiae had tolerance to penicillin (MICs were around 0.063 microgram/ml). Furthermore, the S. agalactiae strains were found to have a paradoxical response to penicillin in an acidic condition (pH 5.5). When the cell counts were performed at pH 5.5, about 10(2) cells survived at penicillin concentrations from 0.016 to 0.125 microgram/ml, while about 10(4) cells survived at the concentrations of 1 to 8 micrograms/ml. The antibiotic tolerance and paradoxical effects of S. agalactiae were also observed in killing kinetics. The ATCC 13,813 and 10 out of 11 clinical strains showed slow response to penicillin-mediated killing at pH 7.8 and ATCC 13,813 and one of the clinical strains showed a reduced response with increase in penicillin concentration at pH 5.5. These results suggested that the tolerance and paradoxical effect of S. agalactiae cells to beta-lactam antibiotics may be one of the reasons for frequent re-colonization of S. agalactiae at the time of delivery after the chemophylaxis in the 2nd trimester.     

A definite case of spondylodiscitis caused by Streptococcus equisimilis

To shed light on the role of Streptococcus equisimilis (SE) in the pathogenesis of intervertebral disc infection, we report here a case of lumbar spondylodiscitis in a 37-year-old male caused by SE, with identification of this strain by cultures from L4-L5 lumbar disc biopsy. Intravenous therapy with penicillin and gentamycin combined with immobilization resulted in a rapid and complete recovery. The patient did not have underlying disease and showed no obvious history of exposure to animals. We conclude that SE may be responsible for both septic arthritis and spondylodiscitis.     

A fresh look at the definition of susceptibility of Streptococcus pneumoniae to beta-lactam antibiotics.

Definitions for susceptibility or resistance of Streptococcus pneumoniae to penicillin were not developed until penicillin-resistant pneumococci appeared in South Africa in the late 1970s. The definition that was accepted (which still remains in use) and later definitions of resistance to most other beta-lactam antibiotics were derived from laboratory and clinical data relating to the treatment of meningitis, not otitis media, sinusitis, or pneumonia. An understanding of the origin of these definitions helps to resolve the apparent paradox that infections of the respiratory tract due to seemingly beta-lactam-resistant pneumococci may still respond well to standard doses of these drugs. A recently sanctioned change in the definition of susceptibility to amoxicillin is helpful in eliminating the paradox for this drug, but it may create further confusion by implying that, on a microgram basis, amoxicillin is substantially more effective than penicillin or third-generation cephalosporins. This article examines definitions of susceptibility and resistance of pneumococci, highlighting areas that have led to confusion and proposing a new way of understanding them.     

Resistance against oral antibiotics to Streptococcus pneumoniae isolated from adult respiratory tract infections

The resistance against oral antibiotics to Streptococcus pneumoniae (S. pneumoniae) isolated from adult patients with respiratory tract infections in the Kurume area in 1998 was studied. The frequency of resistant strains, which were isolated penicillin-intermediate S. pneumoniae and resistant S. pneumoniae (PISP, PRSP) were both 41.2%. We examined the minimal inhibitory concentrations (MIC) of oral antibiotics and the susceptibility ratio of the strains for the drugs based on the breakpoint MIC. The breakpoint MIC of pneumonia against oral beta-lactam antibiotics to PISP, PRSP, which were determined by Japan Society of Chemotherapy, were high in the order of FRPM > CDTR, CFPN > CFTM > CFDN, CPDX. In the case of the new oral quinolones, DU6859a > SPFX > LVFX > CPFX showed good results, in this order, DU6859a showed the most significant inhibitory effect to PISP, PRSP (MIC90 0.06 microgram/ml). By serotyping the percentage of 19, 6, 23 was 42.9%, 21.4% and 14.3%.     

2010年至2017年苏州地区儿童肺炎链球菌的流行特点与耐药性研究

目的:探讨肺炎链球菌流行的分布特征及其耐药性的变化趋势,为临床合理使用抗菌药物提供依据。方法:回顾性分析2010年1月至2017年12月苏州大学附属儿童医院收集的呼吸道感染患儿痰标本中肺炎链球菌检出情况及其药物敏感试验结果。分别比较不同性别、年龄、年份和季节的肺炎链球菌检出率。采用Mann-Kendall趋势检验法分析...     

Early switch from intravenous to oral antibiotics in hospitalized patients with bacteremic community-acquired Streptococcus pneumoniae pneumonia

BACKGROUND: The identification of Streptococcus pneumoniae bacteremia in hospitalized patients with community-acquired pneumonia is considered by some investigators to be an exclusion criterion for early switch from intravenous to oral therapy. OBJECTIVE: To determine whether the switch from intravenous to oral therapy in such patients, once the bx;1patient reaches clinical stability, is associated with poor clinical outcome. METHODS: The medical records of 400 patients with community-acquired pneumonia hospitalized at the Veterans Affairs Medical Center of Louisville (Louisville, Ky) were reviewed to identify patients with bacteremic S pneumoniae. Four criteria were used to define when a patient reached clinical stability and should be considered a candidate for switch therapy: (1) cough and shortness of breath are improving, (2) patient is afebrile for at least 8 hours, (3) white blood cell count is normalizing, and (4) oral intake and gastrointestinal tract absorption are adequate. RESULTS: A total of 36 bacteremic patients were identified. No clinical failures occurred in 18 patients who reached clinical stability and were switched to oral therapy or in 7 patients who reached clinical stability and continued intravenous therapy. Clinical failures (5 deaths) occurred in the group of 11 patients who did not reach clinical stability. CONCLUSION: Once a hospitalized patient with community-acquired pneumonia reaches clinical stability, it is safe to switch from intravenous to oral antibiotics even if bacteremia caused by S pneumoniae was initially documented.