Empyema Caused by Streptococcus Constellatus: A Case Report

1. Abstract Background: Streptococcus constellatus is an opportunistic pathogen of Streptococcus angina. It is easily to be ignored by routine clinical laboratory tests for it sprolonged anaerobic cultur e environment

Case Presentation: A 47-year-old man was admitted to our hospital due to chest pain for more than 10 days. Chest comput- ed tomography showed patchy opacities and rightsided pleural effusion, so a chest tube was inserted and purulent and hemor- rhagic fluid was aspirated. The routine etiological examinationsof the pleural effusion were all negative, and bacteria culture de- tected Streptococcus constellatus. Intravenous Penicillin sodium (3.2MIU, ivgtt, Q8h) combined with ornidazole (500mg, ivgtt, Qd) was used accordingly. The patient recovered and subsequent chest computed tomography confirmed the improvement.

Conclusions: We reported a case of empyema to Streptococ- cus constellatus infection, which was identified by bacterial culture. This reminds us that we should be alert to the occurrence of opportunistic infections that are not common in people with nor- mal immune function. Streptococcus constellatus is an opportunistic pathogen of Streptococcus angina (also known as Streptococcus Miller), which can cause purulent infections in various organs of the body when the body’sresistancedecreases.Hereistoreportacaseofempyema

Keywords: Streptococcus Constellatus; Empyema; Thoracic irrigation

2. Case Presentation A47-year-old middle-aged male patient was admitted to our hospital on February 7, 2021 due to “chest pain for more than 10 days”.Tendaysago,thepatienthadchestpainwithoutobviousinducement,whichwasmilddullpain.Itwasobviouswhenbreath- ing deeply, accompanied by chest tightness, shortness of breath, occasional cough and expectoration. He felt no chills, no fever,no fatigue, no night sweats and other discomforts. After taking ibuprofen capsules, the chest pain was slightly improved. He still had chestpain when breathingdeeply, sohecame to our hospital. Since the on set of the disease,the patient’smentals leepisaccept- able, appetite is not good, urine and urine are normal, and weight has not changed significantly. The patient had no special medical history.Physicalexaminationonadmission:Temperature:39.2 ℃, Pulse: 99 times/min, Respiration: 20 times/min, Blood Pressure:124/72mmHg,conscious,nopalpableswellingofsuperficial lymphnodesalloverthebody,lowbreathsoundsintherightlow- er lung, clear breath sounds in the left lung, no dry and wet rales andpleuralfrictionsounds,noenlargementoftheheartboundary, heart rate was 99 times/min and regular rhythm. No pathological murmur was heard in the auscultatory area of each valve. The abdomen is flat and soft. Abdominal tenderness and abdominal muscletensionwereabsent,abdominalmasswasnotpalpable, liverandspleenwerenotpalpableunderthecostalmargin,bowel sounds were normal, lower limbs were not swollen, and pathological signs were negative. Further examination after admission: WBC 24.40 × 109/L ↑, Neutrophil count 21.15 × 109/L ↑, Neutrophil ratio 86.8% ↑; Liver Function: Albumin 25.8g/L ↓, LDH 200.0U/L;BNP208.0PG/ml;PCT0.542ng/ml↑,ESR97mm/H↑; CRP299.00mg/L↑;Coagulationfunction:prothrombintime14.4s ↑,internationalnormalizedratio1.27↑,prothrombintimeratio 1.26 ↑, fibrinogen concentration 10.0 G/L ↑, percent activity of prothrombintime69.8%↓,D-dimerquantitation1.82μg/mlFEU ↑,Completesetofpneumonia:Mycoplasmapneumoniaeantibody (MP-Ab) positive (+) 1:40, the rest negative; Sputum acid-fast staining was negative; Renal function, electrolyte, blood glucose, blood lipid, epidemic hemorrhagic fever antibody IgG, epidem-ic hemorrhagic fever antibody IgM, HIV antibody antigen, Treponema pallidum antibody, influenzaAvirus nucleic acid (PCR), influenza B virus nucleic acid (PCR), PPD skin test, γ-interferon release test, sputum culture and blood culture were normal; BedsideECGshowedsinustachycardiaandrightbundlebranchblock. Lung CT showed right atelectasis and right pleural effusion. The cause remains to be investigated. Enlarged lymph nodes in mediastinum.ThoracocentesiswasperformedafterthoraciccolorDopplerultrasoundlocalization,andalargeamountofturbid,milky white pleural effusion with foul odor was drained, and specimens were taken for examination. Pleural Effusion analysis showed: Milky white and dturbid, positive in Levantine’s test, total cell count: 28400 × 106/L, WBC count: 22400 × 106/L, percentageof mononuclear cells: 0.10, percentage of multinucleated cells: 0.90; total protein: 4.5 G/L, chloride: 97.2 mmol/L, Glucose: 0.5 mmol/L, LDH: 3955.0 U/L,ADA: 202.9 U/L; CEAin pleural effusionwas200.870ng/L;Pleuralfluidanaerobicbacteriaculture: Streptococcusconstellatus,sensitivetocefotaxime,linezolid,levofloxacin, meropenem, penicillin, tetracycline and vancomycin, notapplicabletoamoxicillin,moxifloxacinandteicoplanin,resistanttoclindamycinanderythromycin.Atthispoint,thepatientwas definitely diagnosed as: Streptococcus constellatus empyema on the left. Penicillin sodium (3.2MIU, ivgtt, Q8h) combined with ornidazole (500mg, ivgtt, Qd) was given for anti-infection treatment. At the same time, improved thoracoscopy and pleural lavage (sodium bicarbonate 200ml+normal saline 200ml, Qd) were given. The patient’s temperature showed a downward trend, and returnedtonormalafter3days.LungCT wasreexaminedafter 7 days, and it was significantly better than before (see the figure below).Thepatientwasdischargedwithoralantibioticsforfurther treatment and outpatient follow-up (Figure 1).

3. Discussion Streptococcus constellatus viridans group, a species of Streptococcus angina (also known as Streptococcus Miller). In the same genusareStreptococcusanginaandStreptococcusintermedia[1]. There are two subspecies of Streptococcus Constellatus, Streptococcus Constellatus and Angina. The streptococcus constellatusis a gram-positive coccus which is arranged in double chains or shortchains,itcanformgray-white,needle-sized,convex,round, smooth and moist colonies with neat edges and obvious β-hemolyticringsonbloodplates[2].Thebacteriaarewidelydistributed in nature, such as human body surface, oral cavity and intestinal tract.Itisusuallyanopportunisticpathogen,andthelowimmunity ofthebodyoftencausessuppurativeinfection[3].Claridgeetal. [4] analyzed 118 cases of Streptococcus constellatus determined by 16s rRNA gene testing, and found that compared with Streptococcus angina, Streptococcus constellatus and Streptococcus intermediaweremorelikelytoformdeeppurulentlesions.Empy- ema, liver abscess, septicemia, odontogenic abscess, intrauterine pyogenic infection, pyogenic spondylitis, neck abscess, necrotizing mediastinitis, and even brain abscess caused by Streptococcus constellatus have been reported.There are few reports of empyema caused by Streptococcus constellatus at home and abroad [1,5-8]. Wang Xueqiao et al. [9] analyzed the characteristics of pathogenicbacteriain339casesofadultthoracicinfection.Itwas concludedthatgram-negativebacteriawerethemainpathogensof thoracicinfection,andonly12.4%(17/137)ofthemwerecaused bygram-positivebacteriasuchasStreptococcusconstellatus.One case of Streptococcus constellatus empyema was confirmed by bacterial culture of pleural effusion, and two cases of Streptococcus constellatus empyema reported by Li Pei et al. [8] and Jiang Yinling et al. [1] had cough, expectoration and chest pain as the main symptoms. Chest CTshowed pleural effusion. Comparative analysis, the patient reported in this article, after admission, detailed medical history, physical examination and complete examination, mainly manifested as chest pain, low breath sounds ontherightempyemasideofchestauscultation,andobviouspleural effusion on B-mode ultrasound and CT. The effusion drained by thoracocentesiswasturbidbrown,similartomilktea,withsevere odor. Empyema is a suppurative infection of the thoracic cavity. Thetreatmentofempyemaismainlytothoroughlywashanddrain thepus,promotethelungtissuetoexpandassoonaspossible,and actively search for pathogens, carry out drug sensitivity tests, and selectsensitiveandeffectiveantibioticsaccordingtothesensitivityofpathogenstodrugs.Thisarticlereportsthatthepatientunderwentultrasoundlocalizationandthoracicpuncturedrainageintime after admission. And after consummation thoracoscopy, flushes theabscesscavityunceasingly,ontheonehandalleviatestheclin- ical sign and symptom, on the other hand can retain the specimen tosendintime.YangChunlingetal.[2]haveconductedantimicrobialsusceptibilitytestson30strainsofStreptococcusconstellatus. TheSusceptibilityratestoampicillin,cefazolin,cefuroxime,cefaclor, cefotaxime, ceftriaxone, cefepime, meropenem, panipenem, vancomycin,levofloxacinandofloxacinwere100%,clindamycin 83.3%(25/30)anderythromycin90.0%(27/30).Chloramphenicol 93.3% (28/30). Wu Hongqiao et al. [3] also analyzed the clini-cal infection characteristics and drug resistance of 146 strains of Streptococcus, and showed that the sensitivity rate of Streptococcusconstellatustoerythromycinandclindamycinwaslow,both< 20.0%,butitwassensitivetomanyotherantibiotics.Accordingly, penicillins and their derivatives can be preferentially selected for the treatment of empyema caused by streptococcus constellatus, andtheconventionaldosagecanbeusedfor6to8weeks.Oruntil the abscess cavity and inflammation in the chest disappear with only a small amount of residual fibrosis. The patient reported in thisarticlewassensitivetotheempiricallyselectedlevofloxacinat the time of admission, but the patient’s temperature was not well controlled before thoracentesis and drainage, and was changed to the same sensitive penicillins + ornidazole after empyema drainage and washing (the patient’s pleural effusion was turbid with severeodor.Donotruleoutanaerobicinfection,socombineduse of ornidazole (anti-infection), combined treatment achieved good results. It can be seen that timely drainage of pleural effusion can relieve the symptoms of patients and control infection. Inaddition,Noguchietal.[10]analyzedtheclinicalcharacteristics ofpatientswithrespiratorysysteminfectioncausedbyStreptococcus anginae, and concluded that Streptococcus constellatus respiratorysysteminfectioniscommoninmen,mostofthemhave underlying diseases, the typical manifestation is pleural effusion, and half of the pleural effusion is empyema after further examination. The patient reported in this paper is a middle-aged man without underlying diseases.After admission, there was no obvious abnormality in the relevant examinations (HIV,TP, hepatitis, thyroid function, etc.). For the occurrence of empyema caused by Streptococcusconstellatusinfection,itwasconsideredthatthepatient ate less recently, lacked exercise and had low immunity. It wassuggestedthatthepatientshouldpayattentiontooralhygiene in daily life, quit smoking and drinking, eat high-quality protein diet,andstrengthenexerciseandexercise.Enhanceimmunityand seek medical treatment in time.

4. Funding This work was supported by the Scientific Research Launch Project for new employees of the Second Xiangya Hospital of Central South University.

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Luo Yingquan. Empyema Caused by Streptococcus Constellatus: A Case Report. Annals of Clinical and Medical Case Reports 2023