scholarly journals Impact of Penicillin Nonsusceptibility on Clinical Outcomes of Patients with Nonmeningeal Streptococcus pneumoniae Bacteremia in the Era of the 2008 Clinical and Laboratory Standards Institute Penicillin Breakpoints

2012 ◽  
Vol 56 (9) ◽  
pp. 4650-4655 ◽  
Author(s):  
Seong-Ho Choi ◽  
Jin-Won Chung ◽  
Heungsup Sung ◽  
Mi-Na Kim ◽  
Sung-Han Kim ◽  
...  

ABSTRACTTo investigate the impact of penicillin nonsusceptibility on clinical outcomes of patients with nonmeningealStreptococcus pneumoniaebacteremia (SPB), a retrospective cohort study was performed. The characteristics of 39 patients with penicillin-nonsusceptible SPB (PNSPB) were compared to those of a group of age- and sex-matched patients (n= 78) with penicillin-susceptible SPB (PSSPB). Susceptibility to penicillin was redetermined by using the revised Clinical and Laboratory Standards Institute (CLSI) penicillin breakpoints in CLSI document M100-S18. Although the PNSPB group tended to have more serious initial manifestations than the PSSPB group, the two groups did not differ significantly in terms of their 30-day mortality rates (30.8% versus 23.1%;P= 0.37) or the duration of hospital stay (median number of days, 14 versus 12;P= 0.89). Broad-spectrum antimicrobial agents, such as extended-spectrum cephalosporins, vancomycin, and carbapenem, were frequently used in both the PNSPB and PSSPB groups. Multivariate analysis revealed that ceftriaxone nonsusceptibility (adjusted odds ratio [aOR] = 4.88; 95% confidence interval [CI] = 1.07 to 22.27;P= 0.041) was one of the independent risk factors for 30-day mortality. Thus, when the 2008 CLSI penicillin breakpoints are applied and the current clinical practice of using wide-spectrum empirical antimicrobial agents is pursued, fatal outcomes in patients with nonmeningeal SPB that can be attributed to penicillin nonsusceptibility are likely to be rare. Further studies that examine the clinical impact of ceftriaxone nonsusceptibility in nonmningeal SPB may be warranted.

2012 ◽  
Vol 78 (8) ◽  
pp. 2914-2922 ◽  
Author(s):  
J. P. Bitoun ◽  
S. Liao ◽  
X. Yao ◽  
S.-J. Ahn ◽  
R. Isoda ◽  
...  

ABSTRACTPrevious studies have shown that BrpA plays a major role in acid and oxidative stress tolerance and biofilm formation byStreptococcus mutans. Mutant strains lacking BrpA also display increased autolysis and decreased viability, suggesting a role for BrpA in cell envelope integrity. In this study, we examined the impact of BrpA deficiency on cell envelope stresses induced by envelope-active antimicrobials. Compared to the wild-type strain UA159, the BrpA-deficient mutant (TW14D) was significantly more susceptible to antimicrobial agents, especially lipid II inhibitors. Several genes involved in peptidoglycan synthesis were identified by DNA microarray analysis as downregulated in TW14D. Luciferase reporter gene fusion assays also revealed that expression ofbrpAis regulated in response to environmental conditions and stresses induced by exposure to subinhibitory concentrations of cell envelope antimicrobials. In aGalleria mellonella(wax worm) model, BrpA deficiency was shown to diminish the virulence ofS. mutansOMZ175, which, unlikeS. mutansUA159, efficiently kills the worms. Collectively, these results suggest that BrpA plays a role in the regulation of cell envelope integrity and that deficiency of BrpA adversely affects the fitness and diminishes the virulence of OMZ175, a highly invasive strain ofS. mutans.


2015 ◽  
Vol 59 (4) ◽  
pp. 2113-2121 ◽  
Author(s):  
U. Malik ◽  
O. N. Silva ◽  
I. C. M. Fensterseifer ◽  
L. Y. Chan ◽  
R. J. Clark ◽  
...  

ABSTRACTStaphylococcus aureusis a virulent pathogen that is responsible for a wide range of superficial and invasive infections. Its resistance to existing antimicrobial drugs is a global problem, and the development of novel antimicrobial agents is crucial. Antimicrobial peptides from natural resources offer potential as new treatments against staphylococcal infections. In the current study, we have examined the antimicrobial properties of peptides isolated from anuran skin secretions and cyclized synthetic analogues of these peptides. The structures of the peptides were elucidated by nuclear magnetic resonance (NMR) spectroscopy, revealing high structural and sequence similarity with each other and with sunflower trypsin inhibitor 1 (SFTI-1). SFTI-1 is an ultrastable cyclic peptide isolated from sunflower seeds that has subnanomolar trypsin inhibitory activity, and this scaffold offers pharmaceutically relevant characteristics. The five anuran peptides were nonhemolytic and noncytotoxic and had trypsin inhibitory activities similar to that of SFTI-1. They demonstrated weakin vitroinhibitory activities againstS. aureus, but several had strong antibacterial activities againstS. aureusin anin vivomurine wound infection model. pYR, an immunomodulatory peptide fromRana sevosa, was the most potent, with complete bacterial clearance at 3 mg · kg−1. Cyclization of the peptides improved their stability but was associated with a concomitant decrease in antimicrobial activity. In summary, these anuran peptides are promising as novel therapeutic agents for treating infections from a clinically resistant pathogen.


mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Moon H. Nahm ◽  
Jigui Yu ◽  
Jiri Vlach ◽  
Maor Bar-Peled

ABSTRACT We are exposed daily to many glycans from bacteria and food plants. Bacterial glycans are generally antigenic and elicit antibody responses. It is unclear if food glycans’ sharing of antigens with bacterial glycans influences our immune responses to bacteria. We studied 14 different plant foods for cross-reactivity with monoclonal antibodies (MAbs) against 24 pneumococcal serotypes which commonly cause infections and are included in pneumococcal vaccines. Serotype 15B-specific MAb cross-reacts with fruit peels, and serotype 10A MAb cross-reacts with many natural and processed plant foods. The serotype 10A cross-reactive epitope is 1,6-β-galactosidase [βGal(1-6)], present in the rhamno-galacturonan I (RG-I) domain of pectin. Despite wide consumption of pectin, the immune response to 10A is comparable to the responses to other serotypes. An antipectin antibody can opsonize serotype 10A pneumococci, and the shared βGal(1-6) may be useful as a simple vaccine against 10A. Impact of food glycans should be considered in host-pathogen interactions and future vaccine designs. IMPORTANCE The impact of food consumption on vaccine responses is unknown. Streptococcus pneumoniae (the pneumococcus) is an important human pathogen, and its polysaccharide capsule is used as a vaccine. We show that capsule type 10A in a pneumococcal vaccine shares an antigenic epitope, βGal(1-6), with pectin, which is in many plant foods and is widely consumed. Immune response to 10A is comparable to that seen with other capsule types, and pectin ingestion may have little impact on vaccine responses. However, antibody to pectin can kill serotype 10A pneumococci and this shared epitope may be considered in pneumococcal vaccine designs.


mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Sean Roberts ◽  
Sharon L. Salmon ◽  
Donald J. Steiner ◽  
Clare M. Williams ◽  
Dennis W. Metzger ◽  
...  

ABSTRACTFatal outcomes following influenza infection are often associated with secondary bacterial infections. Allergic airway disease (AAD) is known to influence severe complications from respiratory infections, and yet the mechanistic effect of AAD on influenza virus-Streptococcus pneumoniaecoinfection has not been investigated previously. We examined the impact of AAD on host susceptibility to viral-bacterial coinfections. We report that AAD improved survival during coinfection when viral-bacterial challenge occurred 1 week after AAD. Counterintuitively, mice with AAD had significantly deceased proinflammatory responses during infection. Specifically, both CD4+and CD8+T cell interferon gamma (IFN-γ) responses were suppressed following AAD. Resistance to coinfection was also associated with strong transforming growth factor β1 (TGF-β1) expression and increased bacterial clearance. Treatment of AAD mice with IFN-γ or genetic deletion of TGF-β receptor II expression reversed the protective effects of AAD. Using a novel triple-challenge model system, we show for the first time that AAD can provide protection against influenza virus-S. pneumoniaecoinfection through the production of TGF-β that suppresses the influenza virus-induced IFN-γ response, thereby preserving antibacterial immunity.IMPORTANCEAsthma has become one of the most common chronic diseases and has been identified as a risk factor for developing influenza. However, the impact of asthma on postinfluenza secondary bacterial infection is currently not known. Here, we developed a novel triple-challenge model of allergic airway disease, primary influenza infection, and secondaryStreptococcus pneumoniaeinfection to investigate the impact of asthma on susceptibility to viral-bacterial coinfections. We report for the first time that mice recovering from acute allergic airway disease are highly resistant to influenza-pneumococcal coinfection and that this resistance is due to inhibition of influenza virus-mediated impairment of bacterial clearance. Further characterization of allergic airway disease-associated resistance against postinfluenza secondary bacterial infection may aid in the development of prophylactic and/or therapeutic treatment against coinfection.


2020 ◽  
Vol 41 (04) ◽  
pp. 455-469 ◽  
Author(s):  
Charles Feldman ◽  
Ronald Anderson

AbstractWith the notable exceptions of the United States and Canada in particular, the global burden of disease in adults due to invasive infection with the dangerous respiratory, bacterial pathogen, Streptococcus pneumoniae (pneumococcus) remains. This situation prevails despite the major successes of inclusion of polysaccharide conjugate vaccines (PCVs) in many national childhood immunization programs and associated herd protection in adults, as well as the availability of effective antimicrobial agents. Accurate assessment of the geographic variations in the prevalence of invasive pneumococcal disease (IPD) has, however, been somewhat impeded by the limitations imposed on the acquisition of reliable epidemiological data due to reliance on often insensitive, laboratory-based, pathogen identification procedures. This, in turn, may result in underestimation of the true burden of IPD and represents a primary focus of this review. Other priority topics include the role of PCVs in the changing epidemiology of IPD in adults worldwide, smoking as a risk factor not only in respect of increasing susceptibility for development of IPD, but also in promoting pneumococcal antibiotic resistance. The theme of pneumococcal antibiotic resistance has been expanded to include mechanisms of resistance to commonly used classes of antibiotics, specifically β-lactams, macrolides and fluoroquinolones, and, perhaps somewhat contentiously, the impact of resistance on treatment outcome. Finally, but no less importantly, the role of persistent antigenemia as a driver of a chronic, subclinical, systemic proinflammatory/procoagulant phenotype that may underpin the long-term sequelae and premature mortality of those adults who have recovered from an episode of IPD, is considered.


2019 ◽  
Vol 63 (5) ◽  
Author(s):  
Paul G. Ambrose ◽  
Brian D. VanScoy ◽  
Brian M. Luna ◽  
Jun Yan ◽  
Amber Ulhaq ◽  
...  

ABSTRACT There has been renewed interest in combining traditional small-molecule antimicrobial agents with nontraditional therapies to potentiate antimicrobial effects. Apotransferrin, which decreases iron availability to microbes, is one such approach. We conducted a 48-h one-compartment in vitro infection model to explore the impact of apotransferrin on the bactericidal activity of ciprofloxacin. The challenge panel included four Klebsiella pneumoniae isolates with ciprofloxacin MIC values ranging from 0.08 to 32 mg/liter. Each challenge isolate was subjected to an ineffective ciprofloxacin monotherapy exposure (free-drug area under the concentration-time curve over 24 h divided by the MIC [AUC/MIC ratio] ranging from 0.19 to 96.6) with and without apotransferrin. As expected, the no-treatment and apotransferrin control arms showed unaltered prototypical logarithmic bacterial growth. We identified relationships between exposure and change in bacterial density for ciprofloxacin alone (R2 = 0.64) and ciprofloxacin in combination with apotransferrin (R2 = 0.84). Addition of apotransferrin to ciprofloxacin enabled a remarkable reduction in bacterial density across a wide range of ciprofloxacin exposures. For instance, at a ciprofloxacin AUC/MIC ratio of 20, ciprofloxacin monotherapy resulted in nearly 2 log10 CFU increase in bacterial density, while the combination of apotransferrin and ciprofloxacin resulted in 2 log10 CFU reduction in bacterial density. Furthermore, addition of apotransferrin significantly reduced the emergence of ciprofloxacin-resistant subpopulations compared to monotherapy. These data demonstrate that decreasing the rate of bacterial replication with apotransferrin in combination with antimicrobial therapy represents an opportunity to increase the magnitude of the bactericidal effect and to suppress the growth rate of drug-resistant subpopulations.


2015 ◽  
Vol 53 (7) ◽  
pp. 2262-2270 ◽  
Author(s):  
Tyler E. Warkentien ◽  
Faraz Shaikh ◽  
Amy C. Weintrob ◽  
Carlos J. Rodriguez ◽  
Clinton K. Murray ◽  
...  

Combat trauma wounds with invasive fungal infections (IFIs) are often polymicrobial with fungal and bacterial growth, but the impact of the wound microbiology on clinical outcomes is uncertain. Our objectives were to compare the microbiological features between IFI and non-IFI wounds and evaluate whether clinical outcomes differed among IFI wounds based upon mold type. Data from U.S. military personnel injured in Afghanistan with IFI wounds were examined. Controls were matched by the pattern/severity of injury, including blood transfusion requirements. Wound closure timing was compared between IFI and non-IFI control wounds (with/without bacterial infections). IFI wound closure was also assessed according to mold species isolation. Eighty-two IFI wounds and 136 non-IFI wounds (63 with skin and soft tissue infections [SSTIs] and 73 without) were examined. The time to wound closure was longer for the IFI wounds (median, 16 days) than for the non-IFI controls with/without SSTIs (medians, 12 and 9 days, respectively;P< 0.001). The growth of multidrug-resistant Gram-negative rods was reported among 35% and 41% of the IFI and non-IFI wounds with SSTIs, respectively. Among the IFI wounds, times to wound closure were significantly longer for wounds withMucoralesgrowth than for wounds with non-Mucoralesgrowth (median, 17 days versus 13 days;P< 0.01). When wounds withMucoralesandAspergillusspp. growth were compared, there was no significant difference in wound closure timing. Trauma wounds with SSTIs were often polymicrobial, yet the presence of invasive molds (predominant types: orderMucorales,Aspergillusspp., andFusariumspp.) significantly prolonged the time to wound closure. Overall, the times to wound closure were longest for the IFI wounds withMucoralesgrowth.


mSphere ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Bob Meek ◽  
Nina Ekström ◽  
Bjørn Kantsø ◽  
Rachael Almond ◽  
Jamie Findlow ◽  
...  

ABSTRACT Surveillance studies are required to estimate the impact of pneumococcal vaccination in both children and the elderly across Europe. The World Health Organization (WHO) recommends use of enzyme immunoassays (EIAs) as standard methods for immune surveillance of pneumococcal antibodies. However, as levels of antibodies to multiple serotypes are monitored in thousands of samples, a need for a less laborious and more flexible method has evolved. Fluorescent-bead-based multiplex immunoassays (MIAs) are suitable for this purpose. An increasing number of public health and diagnostic laboratories use MIAs, although the method is not standardized and no international quality assessment scheme exists. The EU Pneumo Multiplex Assay Consortium was initiated in 2013 to advance harmonization of MIAs and to create an international quality assessment scheme. In a multilaboratory comparison organized by the consortium, agreement among nine laboratories that used their own optimized MIA was assessed on a panel of 15 reference sera for 13 pneumococcal serotypes with the new WHO standard 007sp. Agreement was assessed in terms of assay accuracy, reproducibility, repeatability, precision, and bias. The results indicate that the evaluated MIAs are robust and reproducible for measurement of vaccine-induced antibody responses. However, some serotype-specific variability in the results was observed in comparisons of polysaccharides from different sources and of different conjugation methods, especially for serotype 4. On the basis of the results, the consortium has contributed to the harmonization of MIA protocols to improve reliability of immune surveillance of Streptococcus pneumoniae. IMPORTANCE Serology of Streptococcus pneumoniae is challenging due to existence of multiple clinically relevant serotypes and the introduction of multivalent vaccines in national immunization programs. Multiplex immunoassays (MIAs) are applied as high-throughput cost-effective methods for serosurveillance, and yet laboratories use their own protocols. The aims of this study were to assess the agreement of results generated by MIAs in different laboratories within the EU Pneumo Multiplex Assay Consortium, to analyze factors contributing to differences in outcome, and to create a harmonized protocol. The study demonstrated good agreement of results of MIAs performed by laboratories using controlled assays for determination of levels of vaccine-induced pneumococcal antibodies. The EU Pneumo Multiplex Assay Consortium is open to everyone working in public health services, and it aims to facilitate efforts by participants to run and maintain a cost-effective, reproducible, high-quality MIA platform.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2014-2014
Author(s):  
Lujia Dong ◽  
Zhi-Yong Gao ◽  
Xin-Jian Yu ◽  
Xi-You Tan ◽  
Jin-Hong Liu ◽  
...  

Abstract Abstract 2014 Background: Previous reports have evidenced that donor-recipient HLA disparity is not associated with improved outcomes after URD hematopoietic cell transplantation (HCT). Some data indicates that Haploidentical (haplo) HCT may result in lower relapse and better outcomes than HLA-identical sibling transplantation in lymphoma. Unfortunately, HLA disparity coming along with severe GVHD and infectious diseases may counteract any benefits from this potentially intensive graft-versus-leukemia (GVL) effects. Here we investigate the impact of donor types on clinical outcomes in 233 patients with hematological malignancies from our single BMT Center. Patients and methods: The outcomes of 233 patients, median age 23 years (4–62), with leukemia undergoing HLA-matched sibling(MRD) (n=52), unrelated (URD) (n=52) and related HLA-mismatched/haploidentical (haplo) (n =129) HCT, performed during the same time period (2007–2012) in single Med Center were compared. Patients received either BUCY2 or BUFlu in HLA-identical sibling HCT, and BUCY + ATG or BUFlu +ATG in URD and haplo cohorts as conditioning regimens, followed by G-CSF mobilized unmanipulated marrow and/or peripheral blood (PB) transplantation. All HLA typing has been performed using high-resolution DNA techniques. In haplo cohort, a hundred-four patients were 3/6 identical, 4 were 4/6 identical and 21 were 5/6 identical at HLA-A,-B, and -DRB1. In URD cohort, thirty-one were 8/8 identical, 13 were 7/8 identical and 8 were 6/8 identical at HLA-A,-B,-Cw and -DRB1. The median number of infused nucleated cells and CD34+ cells were 7.5×108/kg and 5.8×106/kg, respectively. 100/129 haplo, 36/52 URD and 14/52 sibling HCT received HLA 3/6–5/6 matched unrelated CB or haplo BM co-transplantation on day –1 as “third party” cells. GVHD prophylaxis consisted of CSA, MMF and short-term MTX. Results: The median follow-up was 23 mon. (range, 2.5mon.-59.2mon.). All patients engrafted to ANC exceeding 0.5× 109/L at 13.5 d (range, 10–19 d) in matched HCT and URD vs. 125 patients engrafted in haplo patients at 13.5d (8–25d). All patients achieved platelet engraftments in both matched and URD cohorts, at 13.5 d (10–22 d) vs. 124 patients engrafted at 13.5d (9–36 d) in haplo, respectively. Univariate analyses showed that the probability of grades 1–4 acute GVHD at 100 days in MRD, URD and haplo were 42%((95% confidence interval [CI], 28%-56%) vs. 48% (CI, 34%-62%) vs. 63%(CI, 54%-71%, P=0.006), respectively. But aGVHD3-4 were only 10%(CI, 3%-21%) vs. 25%(CI, 14%-39%) vs., 19%(CI, 12%-26%, P=0.155), respectively. The 3-year relapse and TRM rates were 34.6% vs. 13% vs. 17.3%(P=0.0126) and 12.7% vs. 30.2 vs. 21%(P= 0.0496) for patients who underwent MRD, URD and haplo transplantation, respectively. The 3-year RRM rates were 29.2% vs. 24.7% vs. 11.6%(P=0.018)after matched vs. URD vs. haplo, respectively. The 3-year Over all survival(OS)probabilities were 61.8% (range, 48.5%-78.4%), 52.5% (38.6%-71.9%) and 69.8 % (61.6%-79.1%) after the matched, URD and haplo HCT, respectively. There were no differences in survival probabilities according to donor types (P= 0.2743). But further analyses indicated that the 3-year OS for patients with early/intermediate disease were 71.8%, 57.3% and 80.2%, P=0.0401, while patients with advanced disease were 36%, 31.8% and 44.2% (P=0.9633)after the matched, URD and haplo transplantation, respectively. Tests in the multivariate analyses indicated that diseases in advanced stage, long period between diagnoses and transplantation, as well as acute GVHD 3–4 were all correlated with lower survival. Conclusion: These data suggest that HLA disparity in Haplo HCT results in relatively lower relapse and RRM, accepted TRM and improvement of survival for hematological malignant patients, especially in early and intermediate disease. The GVL effect using family HLA mismatched donors may be superior to HLA-identical siblings HCT. URD HCT also have lower relapse but do not associated with improvement of OS because relatively high TRM. Family –mismatched /haploidentical HCT should not be the last choice for these patients with Hematological Malignancies. Choosing the best haploidentical donor and further reduction of relapse and infectious complications in the future will lead to better clinical outcomes. Studies with more patients enrolled are undertaken. Disclosures: No relevant conflicts of interest to declare.


2013 ◽  
Vol 57 (4) ◽  
pp. 1632-1637 ◽  
Author(s):  
Ward Rodgers ◽  
Ashley D. Frazier ◽  
W. Scott Champney

ABSTRACTThe continuing increase in antibiotic-resistant microorganisms is driving the search for new antibiotic targets and improved antimicrobial agents. Ketolides are semisynthetic derivatives of macrolide antibiotics, which are effective against certain resistant organisms. Solithromycin (CEM-101) is a novel fluoroketolide with improved antimicrobial effectiveness. This compound binds to the large 50S subunit of the ribosome and inhibits protein biosynthesis. Like other ketolides, it should impair bacterial ribosomal subunit formation. This mechanism of action was examined in strains ofStreptococcus pneumoniae,Staphylococcus aureus, andHaemophilus influenzae. The mean 50% inhibitory concentrations (IC50s) for solithromycin inhibition of cell viability, protein synthesis, and growth rate were 7.5, 40, and 125 ng/ml forStreptococcus pneumoniae,Staphylococcus aureus, andHaemophilus influenzae, respectively. The net formation of the 50S subunit was reduced in all three organisms, with IC50s similar to those given above. The rates of 50S subunit formation measured by a pulse-chase labeling procedure were reduced by 75% in cells growing at the IC50of solithromycin. Turnover of 23S rRNA was stimulated by solithromycin as well. Solithromycin was found to be a particularly effective antimicrobial agent, with IC50s comparable to those of telithromycin and significantly better than those of azithromycin and clarithromycin in these three microorganisms.


Sign in / Sign up

Export Citation Format

Share Document