Microbiology and risk factors for gram-positive Cocci bacteremia in biliary infections

Background:The rapid antibiotics treatment targeted to a specific pathogen can improve clinical outcomes of septicemia.We aimed to evaluate the clinical characteristics and outcomes of biliary septicemia caused by cholangitis or cholecystitis according to causative organisms.Methods:We performed a retrospective cohort study in 151 patients diagnosed with cholangitis or cholecystitis with bacterial septicemia from January 2013 to December 2015.All patients showed clinical evidence of biliary tract infection and had blood isolates that demonstrated septicemia.Results:Gram-negative,gram-positive,and both types of bacteria caused 84.1%(127/151),13.2%(20/151),and 2.6%(4/151)episodes of septicemia,respectively.The most common infecting organisms were Escherichia coli among gram-negative bacteria and Enterococcus species(Enterococcus casseliflavus and Enterococcus faecalis)among gram-positive bacteria.There were no differences in mortality,re-admission rate,and need for emergency decompression procedures between the gram-positive and gram-negative septicemia groups.In univariate analysis,previous gastrectomy history was associated with gram-positive bacteremia.Multivariate analysis also showed that previous gastrectomy history was strongly associated with gram-positive septicemia(Odds ratio=5.47,95%CI:1.19–25.23;P=0.029).Conclusions:Previous gastrectomy history was related to biliary septicemia induced by gram-positive organisms.This information would aid the choice of empirical antibiotics.

Comparison of the serum contents of inflammatory mediators and oxidative stress mediators between patients with gram-positive bacteria and gram-negative bacteria infection

Objective: To compare the serum contents of inflammatory mediators and oxidative stress mediators between patients with gram-positive bacteria and gram-negative bacteria infection. Methods: Patients who were diagnosed with bloodstream bacterial infection in Zigong Third People's Hospital between March 2015 and April 2017 were selected as the research subjects and divided into gram-positive group and gram-negative group according to the results of blood culture and strain identification, and serum levels of inflammatory mediators PCT, IL-1β, IL-6, sTREM-1, TNF-α, NGAL, SAA, HPT and hs-CRP as well as oxidative stress mediators MDA, AOPP, TAC, CAT and SOD were determined. Results: Serum PCT, IL-1β, IL-6, sTREM-1, TNF-α, NGAL, SAA, HPT, hs-CRP, MDA and AOPP levels of gram-negative group were greatly higher than those of gram-positive group while TAC, CAT and SOD levels were greatly lower than those of gram-positive group. Conclusion: The changes of inflammatory mediators and oxidative stress mediators in the serum of patients with gram-negative bacteria infection are more significant than those of patients with gram-positive bacteria infection.

Causative Microorganisms Isolated from Patients with Intra-Abdominal Infections and Their Drug Resistance Profiles:An 11-Year(2011–2021)Single-Center Retrospective Study

Objective To investigate the distribution and antimicrobial susceptibility of causative microorganisms recovered from patients with intra-abdominal infections(IAIs).Methods A total of 2,926 bacterial and fungal strains were identified in samples collected from 1,679 patients with IAIs at the Peking Union Medical College Hospital between 2011 and 2021.Pathogenic bacteria and fungi were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.Antimicrobial susceptibility testing(AST)was performed using the VITEK 2 compact system and the Kirby–Bauer method.AST results were interpreted based on the M100-Ed31 clinical breakpoints of the Clinical and Laboratory Standards Institute.Results Of the 2,926 strains identified,49.2%,40.8%,and 9.5%were gram-negative bacteria,gram-positive bacteria,and fungi,respectively.Escherichia coli was the most prevalent pathogen in intensive care unit(ICU)and non-ICU patients;however,a significant decrease was observed in the isolation of E.coli between 2011 and 2021.Specifically,significant decreases were observed between 2011 and 2021 in the levels of extended-spectrumβ-lactamase(ESBL)-producing E.coli(from 76.9%to 14.3%)and Klebsiella pneumoniae(from 45.8%to 4.8%).Polymicrobial infections,particularly those involving co-infection with gram-positive and gram-negative bacteria,were commonly observed in IAI patients.Moreover,Candida albicans was more commonly isolated from hospital-associated IAI samples,while Staphylococcus epidermidis had a higher ratio in community-associated IAIs.Additionally,AST results revealed that most antimicrobial agents performed better in non-ESBL-producers than in ESBL-producers,while the overall resistance rates(56.9%–76.8%)of Acinetobacter baumanmii were higher against all antimicrobial agents than those of other common gram-negative bacteria.Indeed,Enterococcus faecium,Enterococcus faecalis,S.epidermidis,and S.aureus were consistently found to be susceptible to vancomycin,teicoplanin,and linezolid.Similarly,C.albicans exhibited high susceptibility to all the tested antifungal drugs.Conclusion The distribution and antimicrobial susceptibility of the causative microorganisms from patients with IAls were altered between 2011 and 2021.This finding is valuable for the implementation of evidence-based antimicrobial therapy and provides guidance for the control of hospital infections.

Effect of"Fuzheng Qingretonglin"decoction on complex urinary tract infection in rats by regulating NLRP3 inflammasome pathway

Obiective:To investigate whether"Fuzheng Qingretonglin"decoction can reduce urinary tract damage caused by complex urinary tract infection caused by drug resistant Escherichia coli by regulating Nod-like receptor pyrin domain3 inflammasome,and to explore the feasibility of this decoction combined with levofloxacin in the treatment of complex urinary tract infection caused by drug resistant bacteria.Methods:SD rats were divided into five groups:sham group,model group,levofloxacin group(Lev group),levofloxacin+Fuzheng Qingre Tonglin decoction group(FZ+lev group),and Fuzheng Qingre Tonglin decoction group(FZQRTL group).After the experiment,urine was taken for bacterial culture to determine the urinary tract infection of rats in each group;HE staining was used to observe the pathological changes of kidney and bladder tissues in rats;The expression of NLRP3 in kidney and bladder tissues was detected by immunohistochemistry;The expression of IL-1βand IL-18 in serum of rats was detected by ELISA;The expressions of NLRP3,ASC and Caspase-1 were detected by Western blotting.Results:The positive rate of urine bacteria culture in the sham group was 0%,the positive rate of urine bacteria culture in the model group was 100%;and the positive rate of urine bacteria culture in the FZ+lev group was 37.50%,which was statistically different from that in the model group(P<0.05).A large number of inflammatory cells were observed in the kidney and bladder tissues of the model group by HE staining,while the number of inflammatory cells in the kidney and bladder tissues of the Lev group and FZQRTL group was significantly reduced compared with that of the model group.The FZ+lev group in the number and structure of inflammatory cells in kidney and bladder were similar to the sham group.The NLRP3 immunohistochemistry of kidney and bladder tissue in FZ+lev groups and FZQRTL groups was significantly different from that in model group(P<0.001).The levels of IL-1βand IL-18 in serum of Lev group,FZQRTL group and FZ+lev group were significantly decreased by ELISA compared with model group(P<0.001).The levels of IL-1βand IL-18 in the FZ+lev groups were significantly lower than in the Lev group and FZQRTL group,and the differences were statistically significant(P<0.05).The protein expressions of NLRP3,ASC and Caspase-1 in the Lev group,FZQRTL group and FZ+lev group were significantly lower than those in the model group(P<0.001).The protein expressions of NLRP3,ASC and Caspase-1 in the FZ+lev groups were significantly lower than in the Lev group and FZQRTL group,and the differences were statistically significant(P<0.05).Conclusions:"Fuzheng Qingretonglin"decoction may have a protective effect on the kidney and bladder of rats with complex urinary tract infection caused by drug-resistant Escherichia coli by inhibiting the activation of NLRP3 inflammatory bodies,and TCM combined with levofloxacin has a better therapeutic effect than TCM or levofloxacin alone.

Obligate aerobic, gram-positive, weak acid-fast, nonmotile bacilli, Tsukamurella tyrosinosolvens: Minireview of a rare opportunistic pathogen

Tsukamurella species are obligate aerobic,gram-positive,weak acid-fast,nonmotile bacilli.They are found in various environments,such as soil,water,sludge,and petroleum reservoir wastewater,and belong to the order Actinomycetales.In 2016,there was a reclassification of species within the genus Tsukamurella,merging the species Tsukamurella tyrosinosolvens(T.tyrosinosolvens)and Tsukamurella carboxydivorans.Tsukamurella species are clinically considered to be a rare opportunistic pathogen,because most reported cases have been related to bacteremia and intravascular prosthetic devices and immunosuppression.To date,it has been isolated only from human specimens,and has always been associated with clinical disease;human infections are very rare.Reported infections have included pneumonia,brain abscesses,catheter-related bloodstream infections,ocular infections,bacteremia,and sepsis presenting with septic pulmonary emboli in patients who are immunocompromised.To date,there is no commercially available test for identification.On the other hand,sequence-based identification,including matrix-assisted laser desorption ionization time-of-flight mass spectrometry,is an alternative method for identifying clinical isolates that are either slow growers or difficult to identify through biochemical profiling.The golden standards for diagnosis and optimal management still remain to be determined.However,newer molecular biological techniques can provide accurate identification,and contribute to the appropriate selection of definitive therapy for infections caused by this organism.Combinations of several antimicrobial agents have been proposed for treatment,though the length of treatment for infections has yet to be determined,and should be individualized according to clinical response.Immunocompromised patients often experience severe cases due to infection,and life-threatening T.tyrosinosolvens events associated with dissemination and/or failure of source control have occurred.Favorable prognoses can be achieved through earlier identification of the cause of infection,as well as successful management,including appropriate antibiotic therapy together with source control.Further analyses of similar cases are required to establish the most adequate diagnostic methods and treatment regimens for infections.

Drug-resistant genes carried by Acinetobacter baumanii isolated from patients with lower respiratory tract infection

Background Acinetobacter baumanii （A. baumanii ） remains an important microbial pathogen resulting in nosocomialacquired infections with significant morbidity and mortality. The mechanism by which nosocomial bacteria, like A. baumanii, attain multidrug resistance to antibiotics is of considerable interest. The aim in this study was to investigate the spread status of antibiotic resistance genes, such as multiple 13-1actamase genes and aminoglycoside-modifying enzyme genes, from A. baumanii strains isolated from patients with lower respiratory tract infections （LRTIs）. Methods Two thousand six hundred and ninety-eight sputum or the bronchoalveolar lavage samples from inpatients with LRTIs were collected in 21 hospitals in the mainland of China from November 2007 to February 2009. All samples were routinely inoculated. The isolated bacterial strains and their susceptibility were analyzed via VITEK-2 expert system. Several kinds of antibiotic resistant genes were further differentiated via polymerase chain reaction and sequencing methods. Results Totally, 39 A. baumanii strains were isolated from 2698 sputum or bronchoalveolar lavage samples. There was not only a high resistant rate of the isolated A. baumanfi strains to ampicillin and first- and second-generation cephalosporins （94.87%, 100% and 97.44%, respectively）, but also to the third-generation cephalosporins （ceftriaxone at 92.31%, ceftazidine at 51.28%） and imipenem （43.59%） as well. The lowest antibiotic resistance rate of 20.51% was found to amikacin. The OXA-23 gene was identified in 17 strains of A. baumanii, and the AmpC gene in 23 strains. The TEM-1 gene was carried in 15 strains. PER-1 and SHV-2 genes were detected in two different strains. Aminoglycoside-modifying enzyme gene aac-3-1a was found in 23 strains, and the aac-6＂lb gene in 19 strains, aac-3-1a and aac-6＂lb genes hibernated in three A. baumanfi strains that showed no drug-resistant phenotype. Conclusions A. baumanii can carry multiple drug-resistant genes at the same time and result in multi-drug resistance. Aminoglycoside-modifying enzyme genes could be hibernating in aminoglycoside sensitive strains without expressing their phenotype.

A middle-aged lady with a pyogenic liver abscess caused by Clostridium perfringens

The pyogenic liver abscess caused by Clostridium perfringens (C. perfringens ) is a rare, but rapidly fatal infection. It is usually associated with malignancy and immunosuppression. We report the case of 50-year-old lady with the secondary liver metastases from rectal cancer presented with fever and epigastric pain. The identification of Grampositive bacilli septicaemia, the presence of gas-forming liver abscess and massive intravascular hemolysis should lead to the suspicion of C. perfringens infection. Here we review twenty cases published since 1990 and their clinical features are discussed. The importance of "an aggressive treatment policy" with multidisciplinary team approach is emphasized.

Silver nanoparticles-decorated and mesoporous silica coated single-walled carbon nanotubes with an enhanced antibacterial activity for killing drug-resistant bacteria

The mounting threat of antibiotic-resistant bacterial infections has made it imperative to develop innovative antibacterial strategies.Here we propose a novel antibacterial nanoplatform of silver nanoparticles-decorated and mesoporous silica coated single-walled carbon nanotubes constructed via a N-[3-(trimethoxysiltyl)propyl]ethylene diamine(TSD)-mediated method(SWCNTs@mSiO2-TSD@Ag).In this system,the outer mesoporous silica shells are able to improve the dispersibility of SWCNTs,which will increase their contact area with bacteria cell walls.Meanwhile,the large number of mesopores in silica layers act as microreactors for in situ synthesis of Ag NPs with controlled small size and uniform distribution,which induces an enhanced antibacterial activity.Compared with TSD modified mesoporous silica coated single-walled carbon nanotubes(SWCNTs@mSiO2-TSD)and commercialAg NPs,this combination nanosystem of SWCNTs@mSiO2-TSD@Ag exhibits much stronger antibacterial performance against multi-drug-resistant bacteria Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)in vitro through damaging the bacterial cell membranes and a fast release of silver ions.Furthermore,the in vivo rat skin infection model verifies that SWCNTS@mSiO2-TSD@Ag have remarkably improved abilities of bacterial clearance,wound healing promoting as well as outstanding biocompatibility.Therefore,this novel nanoplatform indicates promising potentials as a safe and powerful tool for the treatment of clinical drug-resistant infections.

Ultrasmall Ga-ICG nanoparticles based gallium ion/photodynamic synergistic therapy to eradicate biofilms and against drug-resistant bacterial liver abscess

Pyogenic liver abscess and keratitis are aggressive bacterial infections and the treatment has failed to eradicate bacteria in infectious sites completely owing to the currently severe drug resistance to existing antibiotics.Here,we report a simple and efficient one-step development of ultrasmall non-antibiotic nanoparticles(ICG-Ga NPs)containing clinically approved gallium(Ⅲ)(Ga^(3+))and liver targeting indocyanine green(ICG)molecules to eradicate multi-drug resistant(MDR)bacteria thought the synergetic effect of photodynamic therapy and iron metabolism blocking.The ICG-Ga NPs induced photodynamic effect could destroy the bacterial membrane,further boost the endocytosis of Ga^(3+),then replace iron in bacteria cells to disrupt bacterial iron metabolism,and demonstrate the synergetic bacterial killing and biofilm disrupting effects.The ICG-Ga NPs show an excellent therapeutic effect against extended spectrumβ-lactamases Escherichia coli(ESBL E.coli)and significantly improve treatment outcomes in infected liver abscess and keratitis.Meanwhile,the ultrasmall size of ICG-Ga NPs could be cleared rapid via renal clearance route,guaranteeing the biocompatibility.The protective effect and good biocompatibility of ICG-Ga NPs will facilitate clinical treatment of bacteria infected diseases and enable the development of next-generation non-antibiotic antibacterial agents.

Tuberculosis infection prevention and control:why we need a whole systems approach

Infection prevention and control(IPC)measures to reduce transmission of drug-resistant and drug-sensitive tuberculosis(TB)in health facilities are well described but poorly implemented.The implementation of TB IPC has been assessed primarily through quantitative and structured approaches that treat administrative,environmental,and personal protective measures as discrete entities.We present an on-going project entitled Umoya omuhle(“good air”),conducted in two provinces of South Africa,that adopts an interdisciplinary,‘whole systems’approach to problem analysis and intervention development for reducing nosocomial transmission of Mycobacterium tuberculosis(Mtb)through improved IPC.We suggest that TB IPC represents a complex intervention that is delivered within a dynamic context shaped by policy guidelines,health facility space,infrastructure,organisation of care,and management culture.Methods drawn from epidemiology,anthropology,and health policy and systems research enable rich contextual analysis of how nosocomial Mtb transmission occurs,as well as opportunities to address the problem holistically.A‘whole systems’approach can identify leverage points within the health facility infrastructure and organisation of care that can inform the design of interventions to reduce the risk of nosocomial Mtb transmission.

Enterococcal urinary tract infections: eight years experience at a regional hospital in Trinidad, West Indies

OBJECTIVE: To investigate the prevalence of significant enterococcal isolates from urine and determine what factors are associated with the increased prevalence, with particular reference to antibiotic susceptibilities. METHODS: Retrospective analysis over an 8-year period of hospital laboratory records of urinary isolates of enterococci was done. Species were identified via colony morphology, growth in 6.5% sodium chloride and their ability to hydrolyze esculin in the presence of 40% bile salts. Susceptibility testing via the disc diffusion technique with 9 commonly used antibiotics was also done as defined by the National Committee for Clinical Laboratory Standards. RESULTS: From 39,881 urine specimens, 9116 (22.9%) were culture positive. Of this 9116, 1001 (11.0%) were enterococci, the 4th most common urinary isolate. E. coli was the most common (36.2%). Most enterococci were from pediatric patients (28.4%) and the urology unit (24.5%). All enterococci were fully sensitive to ampicillin and augmentin (amoxicillin-clavulanic acid). Sensitivity to gentamicin decreased significantly from 79% in 1990 to 58% in 1997 (P

Application of ozonated water for treatment of gastro-thoracic fistula after comprehensive esophageal squamous cell carcinoma therapy: A case report

BACKGROUND Gastro-thoracic fistula is a serious complication after radical surgery for esophageal cancer,and a conservative approach or endoscopic intervention is commonly applied to treat most cases.CASE SUMMARY Here we describe the case of a patient with a gastro-thoracic fistula which could not be closed during gastroscopy after receiving postoperative radiotherapy,together with severe multiple drug-resistant bacterial infection and chest wall fistula.The abscess was drained and local irrigation applied with ozonated water,together with oral ozonated water,which achieved a good effect and highlighted a new way to cure fistula in such patients.CONCLUSION Patients with gastro-thoracic fistula that cannot be closed and severe infection can be treated by drainage and flushing with ozonated water.

Clinical efficacy and safety of linezolid in intensive care unit patients

Background:To characterize the population of critically ill patients and infections treated with linezolid in the intensive care unit(ICU),and to evaluate the clinical efficacy and safety of linezolid therapy.Methods::This multi-center,observational,real-world study was conducted across 52 hospitals between June 9,2018,and December 28,2019.Patients who met the following inclusion criteria were included:(1)admitted to the ICU,(2)of any age group,and(3)having a clinical or laboratory diagnosis of a Gram-positive bacterial infection.Clinical efficacy was categorized as success(cured or improved),failed,or non-evaluable.Adverse events and serious adverse events were recorded during treatment.Results::A total of 366 ICU patients who met the inclusion criteria were evaluated.Linezolid was used as second-and first-line treatment in 232(63.4%)and 134(36.6%)patients,respectively.The most common isolated strain was Staphylococcus aureus(methicillin-resistant Staphylococcus aureus:n=37/119,31.1%;methicillin-susceptible Staphylococcus aureus:n=15/119,12.6%);this was followed by Enterococci(vancomycin-resistant Enterococci:n=8/119,6.7%;vancomycin-susceptible Enterococci:n=11/119,9.2%)and Streptococcus pneumoniae(multidrug-resistant:n=4/119,3.4%;non-multidrug resistant:n=2/119,1.7%).The main infection sites where pathogens were detected included the lung(n=216/366,59.6%),skin and soft tissue(n=104/366,28.4%),and blood(n=50/366,13.7%).Clinical success was achieved in 301(82.2%)patients;34(9.3%)were cured and 267(73.0%)improved;treatment failure and non-evaluable outcomes were observed in 29(7.9%)in 36(9.8%)patients,respectively.Linezolid-related adverse events were reported in 8(2.2%)patients.No treatment-related serious adverse events were reported.Conclusions::Based on real-world results,linezolid was found to be effective and safe in the treatment of Gram-positive bacterial infections in critically ill patients.