Jensen, Allan Garlik
Staphylococcus aureus bacteremia (SAB) is still associated with a high mortality, and knowledge on risk factors and the clinical and the therapeutic aspects of SAB is still limited. This thesis focuses on the clinical aspects of SAB and its metastatic infections. In a study of all patients with bacteremia in Copenhagen County October 1992 through April 1993 (study I) we emphasized previous findings, that S. aureus is one of the most frequent pathogens in bacteremia, and in a case control study also in Copenhagen County 1994-95 (study II) we demonstrated, that not only an inserted central venous catheter and nasal S. aureus carriage but also hyponatremia and anemia are important risk factors for hospital-acquired SAB (study II). Studies on the treatment of SAB have pointed out, that the eradication of a primary is important, but there are only limited clinical studies dealing with antibiotic treatment. By logistic regression analysis, we were able to demonstrate that focus eradication is essential, but also that treatment with dicloxacillin 1 g x 4 or 2 g x 3 are superior to 1 g x 3 (studie III), indicating that the time for serum concentration above the Minimal Inhibitory Concentration (MIC) for the bacteria plays a role in the outcome of SAB treatment. S. aureus osteomyelitis secondary to SAB is frequently observed. No other countries, however, have a centralized registration, which make it possible to evaluate a large number of these patients. Since 1960, The Staphylococcal Laboratory, Statens Serum Institut in Copenhagen, has registrated selected clinical informations from nearly all patients with positive blood cultures of S. aureus. Based on this registration, we were able to show an increased number of S. aureus osteomyelitis among older patients and a decreased number of S. aureus osteomyelitis of femur and tibia among younger infants in the period 1980-90 (study IV). By reviewing the records of a large number of patients with vertebral S. aureus
S. van den Berg (Sanne); C.P. de Vogel (Corné); A.F. van Belkum (Alex); I.A.J.M. Bakker-Woudenberg (Irma)
textabstractStaphylococcus aureus carriers with S. aureus bacteremia may have a reduced mortality risk compared to non-carriers. A role for the immune system is suggested. Here, we study in mice the effect of mild S. aureus skin infection prior to endogenous or exogenous S. aureus bacteremia, and ev
Sanne van den Berg
Full Text Available Staphylococcus aureus carriers with S. aureus bacteremia may have a reduced mortality risk compared to non-carriers. A role for the immune system is suggested. Here, we study in mice the effect of mild S. aureus skin infection prior to endogenous or exogenous S. aureus bacteremia, and evaluate protection in relation to anti-staphylococcal antibody levels. Skin infections once or twice by a clinical S. aureus isolate (isolate P or S. aureus strain 8325-4 were induced in mice free of S. aureus and anti-staphylococcal antibodies. Five weeks later, immunoglobulin G (IgG levels in blood against 25 S. aureus antigens were determined, and LD50 or LD100 bacteremia caused by S. aureus isolate P was induced. S. aureus skin infections led to elevated levels of anti-staphylococcal IgG in blood. One skin infection improved the course of subsequent severe endogenous bacteremia only. A second skin infection further improved animal survival rate, which was associated with increased pre-bacteremia IgG levels against Efb, IsaA, LukD, LukE, Nuc, PrsA and WTA. In conclusion, S. aureus isolate P skin infection in mice reduces the severity of subsequent endogenous S. aureus bacteremia only. Although cellular immune effects cannot be rules out, anti-staphylococcal IgG against specified antigens may contribute to this effect.
Burghardt, Elliot L.; Flenker, Katie S.; Clark, Karen C.; Miguel, Jeff; Ince, Dilek; Winokur, Patricia; Ford, Bradley; McNamara, James O.
S. aureus bacteremia (SAB) is a common condition with high rates of morbidity and mortality. Current methods used to diagnose SAB take at least a day, and often longer. Patients with suspected bacteremia must therefore be empirically treated, often unnecessarily, while assay results are pending. In this proof-of-concept study, we describe an inexpensive assay that detects SAB via the detection of micrococcal nuclease (an enzyme secreted by S. aureus) in patient plasma samples in less than three hours. In total, 17 patient plasma samples from culture-confirmed S. aureus bacteremic individuals were tested. 16 of these yielded greater nuclease assay signals than samples from uninfected controls or individuals with non-S. aureus bacteremia. These results suggest that a nuclease-detecting assay may enable the rapid and inexpensive diagnosis of SAB, which is expected to substantially reduce the mortality and morbidity that result from this condition. PMID:27305148
Chapagain, Bikash; Joshi, Astha; Brennessel, Debra J.
Crucial to the management of staphylococcal bacteremia is an accurate evaluation of associated endocarditis, which has both therapeutic and prognostic implications. Because the clinical presentation of endocarditis can be nonspecific, the judicious use of echocardiography is important in distinguishing patients at high risk of developing endocarditis. In the presence of high-risk clinical features, an early transesophageal echocardiogram is warranted without prior transthoracic echocardiography. The purpose of this study was to investigate the clinical risk factors for staphylococcal infective endocarditis that might warrant earlier transesophageal echocardiography and to describe the incidence of endocarditis in cases of methicillin-resistant and methicillin-sensitive Staphylococcus aureus bacteremia. A retrospective case-control study was conducted by means of chart review of 91 patients consecutively admitted to a community hospital from January 2009 through January 2013. Clinical risk factors of patients with staphylococcal bacteremia were compared with risk factors of patients who had definite diagnoses of infective endocarditis. There were 69 patients with bacteremia alone (76%) and 22 patients with endocarditis (24%), as verified by echocardiography. Univariate analysis showed that diabetes mellitus (P=0.024), the presence of an automatic implantable cardioverter-defibrillator/pacemaker (P=0.006) or a prosthetic heart valve (P=0.003), and recent hospitalization (P=0.048) were significantly associated with developing infective endocarditis in patients with S. aureus bacteremia. The incidence of methicillin-resistant and methicillin-sensitive S. aureus bacteremia was similar in the bacteremia and infective-endocarditis groups (P=0.437). In conclusion, identified high-risk clinical factors in the presence of bacteremia can suggest infective endocarditis. Early evaluation with transesophageal echocardiography might well be warranted. PMID:28265207
Mejer, N; Gotland, N; Uhre, M L;
OBJECTIVES: An association between infection and arterial thromboembolic events (ATE) has been suggested. Here we examined the risk of myocardial infarction (MI), stroke and other ATE after Staphylococcus aureus bacteremia (SAB). METHODS: Danish register-based nation-wide observational cohort study...
Smit, Jesper; Søgaard, Mette; Schønheyder, Henrik Carl;
OBJECTIVE: Patients with diabetes may experience higher risk of Staphylococcus aureus bacteremia (SAB) than patients without diabetes due to decreased immunity or coexisting morbidities. We investigated the risk of community-acquired (CA) SAB in persons with and without diabetes. DESIGN: Using...
Oestergaard, Louise B.; Christiansen, Mia N.; Schmiegelow, Michelle D.
BACKGROUND: A genetic predisposition to Staphylococcus aureus bacteremia has been demonstrated in animals, suggesting that genetic differences might influence susceptibility to S aureus in humans. OBJECTIVE: To determine whether a history of S aureus bacteremia in first-degree relatives increases...
Rajan P Adhikari
Full Text Available Staphylococcus aureus (S. aureus is a human pathogen associated with skin and soft tissue infections (SSTI and life threatening sepsis and pneumonia. Efforts to develop effective vaccines against S. aureus have been largely unsuccessful, in part due to the variety of virulence factors produced by this organism. S. aureus alpha-hemolysin (Hla is a pore-forming toxin expressed by most S. aureus strains and reported to play a key role in the pathogenesis of SSTI and pneumonia. Here we report a novel recombinant subunit vaccine candidate for Hla, rationally designed based on the heptameric crystal structure. This vaccine candidate, denoted AT-62aa, was tested in pneumonia and bacteremia infection models using S. aureus strain Newman and the pandemic strain USA300 (LAC. Significant protection from lethal bacteremia/sepsis and pneumonia was observed upon vaccination with AT-62aa along with a Glucopyranosyl Lipid Adjuvant-Stable Emulsion (GLA-SE that is currently in clinical trials. Passive transfer of rabbit immunoglobulin against AT-62aa (AT62-IgG protected mice against intraperitoneal and intranasal challenge with USA300 and produced significant reduction in bacterial burden in blood, spleen, kidney, and lungs. Our Hla-based vaccine is the first to be reported to reduce bacterial dissemination and to provide protection in a sepsis model of S. aureus infection. AT62-IgG and sera from vaccinated mice effectively neutralized the toxin in vitro and AT62-IgG inhibited the formation of Hla heptamers, suggesting antibody-mediated neutralization as the primary mechanism of action. This remarkable efficacy makes this Hla-based vaccine a prime candidate for inclusion in future multivalent S. aureus vaccine. Furthermore, identification of protective epitopes within AT-62aa could lead to novel immunotherapy for S. aureus infection.
Richards, R L; Haigh, R D; Pascoe, B; Sheppard, S K; Price, F; Jenkins, D; Rajakumar, K; Morrissey, J A
Staphylococcus aureus bacteremia cases are complicated by bacterial persistence and treatment failure despite the confirmed in vitro susceptibility of the infecting strain to administered antibiotics. A high incidence of methicillin-resistant S. aureus (MRSA) bacteremia cases are classified as persistent and are associated with poorer patient outcomes. It is still unclear how S. aureus evades the host immune system and resists antibiotic treatment for the prolonged duration of a persistent infection. In this study, the genetic changes and associated phenotypic traits specific to S. aureus persistent bacteremia were identified by comparing temporally dispersed isolates from persistent infections (persistent isolates) originating from two independent persistent S. aureus bacteremia cases with the initial infection isolates and with three resolved S. aureus bacteremia isolates from the same genetic background. Several novel traits were associated specifically with both independent sets of persistent S. aureus isolates compared to both the initial isolates and the isolates from resolved infections (resolved isolates). These traits included (i) increased growth under nutrient-poor conditions; (ii) increased tolerance of iron toxicity; (iii) higher expression of cell surface proteins involved in immune evasion and stress responses; and (iv) attenuated virulence in a Galleria mellonella larva infection model that was not associated with small-colony variation or metabolic dormancy such as had been seen previously. Whole-genome sequence analysis identified different single nucleotide mutations within the mprF genes of all the isolates with the adaptive persistence traits from both independent cases. Overall, our data indicate a novel role for MprF function during development of S. aureus persistence by increasing bacterial fitness and immune evasion.
Richards, R. L.; Haigh, R. D.; Pascoe, B.; Sheppard, S. K.; Price, F.; Jenkins, D.; Rajakumar, K.
Staphylococcus aureus bacteremia cases are complicated by bacterial persistence and treatment failure despite the confirmed in vitro susceptibility of the infecting strain to administered antibiotics. A high incidence of methicillin-resistant S. aureus (MRSA) bacteremia cases are classified as persistent and are associated with poorer patient outcomes. It is still unclear how S. aureus evades the host immune system and resists antibiotic treatment for the prolonged duration of a persistent infection. In this study, the genetic changes and associated phenotypic traits specific to S. aureus persistent bacteremia were identified by comparing temporally dispersed isolates from persistent infections (persistent isolates) originating from two independent persistent S. aureus bacteremia cases with the initial infection isolates and with three resolved S. aureus bacteremia isolates from the same genetic background. Several novel traits were associated specifically with both independent sets of persistent S. aureus isolates compared to both the initial isolates and the isolates from resolved infections (resolved isolates). These traits included (i) increased growth under nutrient-poor conditions; (ii) increased tolerance of iron toxicity; (iii) higher expression of cell surface proteins involved in immune evasion and stress responses; and (iv) attenuated virulence in a Galleria mellonella larva infection model that was not associated with small-colony variation or metabolic dormancy such as had been seen previously. Whole-genome sequence analysis identified different single nucleotide mutations within the mprF genes of all the isolates with the adaptive persistence traits from both independent cases. Overall, our data indicate a novel role for MprF function during development of S. aureus persistence by increasing bacterial fitness and immune evasion. PMID:26056388
Mölkänen, T; Ruotsalainen, E; Thorball, C W;
are scarce. To elucidate the role of suPAR in a common bacteremic infection, the serum suPAR levels in 59 patients with Staphylococcus aureus bacteremia (SAB) were measured using the suPARnostic ELISA assay and associations to 1-month mortality and with deep infection focus were analyzed. On day three, after......PAR levels as compared to patients with no deep infection focus. suPAR was found to be prognostic for mortality in receiver operator characteristic (ROC) curve analysis, which was not observed for serum C-reactive protein (CRP); the area under the curve (AUC) for suPAR was 0.754 (95% confidence interval [CI...
Bouchiat, Coralie; Moreau, Karen; Devillard, Sébastien; Rasigade, Jean-Philippe; Mosnier, Amandine; Geissmann, Tom; Bes, Michèle; Tristan, Anne; Lina, Gérard; Laurent, Frédéric; Piroth, Lionel; Aissa, Nejla; Duval, Xavier; Le Moing, Vincent; Vandenesch, François
Infective endocarditis (IE)((1)) is a severe condition complicating 10-25% of Staphylococcus aureus bacteremia. Although host-related IE risk factors have been identified, the involvement of bacterial features in IE complication is still unclear. We characterized strictly defined IE and bacteremia isolates and searched for discriminant features. S. aureus isolates causing community-acquired, definite native-valve IE (n=72) and bacteremia (n=54) were collected prospectively as part of a French multicenter cohort. Phenotypic traits previously reported or hypothesized to be involved in staphylococcal IE pathogenesis were tested. In parallel, the genotypic profiles of all isolates, obtained by microarray, were analyzed by discriminant analysis of principal components (DAPC)((2)). No significant difference was observed between IE and bacteremia strains, regarding either phenotypic or genotypic univariate analyses. However, the multivariate statistical tool DAPC, applied on microarray data, segregated IE and bacteremia isolates: IE isolates were correctly reassigned as such in 80.6% of the cases (C-statistic 0.83, P<0.001). The performance of this model was confirmed with an independent French collection IE and bacteremia isolates (78.8% reassignment, C-statistic 0.65, P<0.01). Finally, a simple linear discriminant function based on a subset of 8 genetic markers retained valuable performance both in study collection (86.1%, P<0.001) and in the independent validation collection (81.8%, P<0.01). We here show that community-acquired IE and bacteremia S. aureus isolates are genetically distinct based on subtle combinations of genetic markers. This finding provides the proof of concept that bacterial characteristics may contribute to the occurrence of IE in patients with S. aureus bacteremia.
Hetem, David J.; de Ruiter, Susanne C.; Buiting, Anton G. M.; Kluytmans, Jan A. J. W.; Thijsen, Steven F.; Vlaminckx, Bart J. M.; Wintermans, Robert G. F.; Bonten, Marc J. M.; Ekkelenkamp, Miquel B.
Two previous studies in tertiary care hospitals identified Staphylococcus aureus colonization of intravascular (IV) catheters as a strong predictor of subsequent S. aureus bacteremia (SAB), even in the absence of clinical signs of systemic infection. Bacteremia was effectively prevented by timely an
Weinstein Robert A
Full Text Available Abstract Background When Staphylococcus aureus is isolated in urine, it is thought to usually represent hematogenous spread. Because such spread might have special clinical significance, we evaluated predictors and outcomes of S. aureus bacteriuria among patients with S. aureus bacteremia. Methods A case-control study was performed at John H. Stroger Jr. Hospital of Cook County among adult inpatients during January 2002-December 2006. Cases and controls had positive and negative urine cultures, respectively, for S. aureus, within 72 hours of positive blood culture for S. aureus. Controls were sampled randomly in a 1:4 ratio. Univariate and multivariable logistic regression analyses were done. Results Overall, 59% of patients were African-American, 12% died, 56% of infections had community-onset infections, and 58% were infected with methicillin-susceptible S. aureus (MSSA. Among 61 cases and 247 controls, predictors of S. aureus bacteriuria on multivariate analysis were urological surgery (OR = 3.4, p = 0.06 and genitourinary infection (OR = 9.2, p = 0.002. Among patients who died, there were significantly more patients with bacteriuria than among patients who survived (39% vs. 17%; p = 0.002. In multiple Cox regression analysis, death risks in bacteremic patients were bacteriuria (hazard ratio 2.9, CI 1.4-5.9, p = 0.004, bladder catheter use (2.0, 1.0-4.0, p = 0.06, and Charlson score (1.1, 1.1-1.3, p = 0.02. Neither length of stay nor methicillin-resistant Staphylococcus aureus (MRSA infection was a predictor of S. aureus bacteriuria or death. Conclusions Among patients with S. aureus bacteremia, those with S. aureus bacteriuria had 3-fold higher mortality than those without bacteriuria, even after adjustment for comorbidities. Bacteriuria may identify patients with more severe bacteremia, who are at risk of worse outcomes.
Lucieni de Oliveira Conterno
Full Text Available Staphylococcus aureus is an important pathogen causing bacteremia, primarily affecting hospitalized patients. We studied the epidemiology of S. aureus bacteremia, comparing two periods (early and mid 1990s and developed a predictive model of mortality. A nested case-control was done. All 251 patients over 14 years old with positive blood cultures for S. aureus were selected. MRSA (methicillin resistant S. aureus was isolated in 63% of the cases. When comparing the two periods MRSA community-acquired bacteremia increased from 4% to 16% (p=0.01. There was no significant difference in the mortality rate between the two periods (39% and 33%, p=0.40. Intravascular catheters provoked 24% of the cases of bacteremia and were associated with the lowest rate of mortality. In a logistic regression analysis, three variables were associated with death: septic shock, source of bacteraemia and resistance to methicillin. The probability of dying among patients with MRSA and those with methicillin sensitive S. aureus bacteraemia ranged from 10% to 90% and from 4% to 76%, respectively, depending on the source of the bacteraemia and the occurrence of septic shock. The MRSA found in Brazil may be a particularly virulent strain.
Richards, R L; Haigh, R. D.; Pascoe, B.; Sheppard, S.K.; Price, F.; Jenkins, D.; Rajakumar, K; Morrissey, J. A.
Staphylococcus aureus bacteremia cases are complicated by bacterial persistence and treatment failure despite the confirmed in vitro susceptibility of the infecting strain to administered antibiotics. A high incidence of methicillin-resistant S. aureus (MRSA) bacteremia cases are classified as persistent and are associated with poorer patient outcomes. It is still unclear how S. aureus evades the host immune system and resists antibiotic treatment for the prolonged duration of a persistent in...
S. Lautenschlager; C. Herzog; W. Zimmerli
textabstractIn a retrospective survey of patients hospitalized in the University Hospital of Basel, Switzerland, the course and outcome of 281 cases of true bacteremia due to Staphylococcus aureus over a 7-year period were analyzed. The main purpose was to evaluate different case definitions. In 78%
Smit, Jesper; Kaasch, Achim J; Søgaard, Mette;
OBJECTIVE: To investigate whether the use of systemic glucocorticoids is a risk factor for community-acquired Staphylococcus aureus bacteremia (CA-SAB). PATIENTS AND METHODS: We used population-based medical registries in Northern Denmark to conduct a case-control study including all adults...
Frederiksen, Marianne Sjølin; Espersen, Frank; Frimodt-Møller, Niels;
BACKGROUND: Staphylococcus aureus is known to be a leading cause of bacteremia in childhood, and is associated with severe morbidity and increased mortality. To determine developments in incidence and mortality rates, as well as risk factors associated with outcome, we analyzed data from 1971...
H.A. Verbrugh (Henri); W.H.F. Goessens (Wil); M.F. Michel; R. Peters (Roel)
textabstractAntibody responses to staphylococcal α-toxin, cell wall teichoic acid, and cell wall peptodoglycan were measured in 259 serum samples from 74 consecutive patients with Staphylococcus aureus bacteremia. All patients with complicated bacteremia were seropositive in at least one of three te
Calderwood, Michael S.; Desjardins, Christopher A.; Sakoulas, George; Nicol, Robert; DuBois, Andrea; Delaney, Mary L.; Kleinman, Ken; Cosimi, Lisa A.; Feldgarden, Michael; Onderdonk, Andrew B.; Birren, Bruce W.; Platt, Richard; Huang, Susan S.
Background. Methicillin-resistant Staphylococcus aureus (MRSA) colonization predicts later infection, with both host and pathogen determinants of invasive disease. Methods. This nested case-control study evaluates predictors of MRSA bacteremia in an 8–intensive care unit (ICU) prospective adult cohort from 1 September 2003 through 30 April 2005 with active MRSA surveillance and collection of ICU, post-ICU, and readmission MRSA isolates. We selected MRSA carriers who did (cases) and those who did not (controls) develop MRSA bacteremia. Generating assembled genome sequences, we evaluated 30 MRSA genes potentially associated with virulence and invasion. Using multivariable Cox proportional hazards regression, we assessed the association of these genes with MRSA bacteremia, controlling for host risk factors. Results. We collected 1578 MRSA isolates from 520 patients. We analyzed host and pathogen factors for 33 cases and 121 controls. Predictors of MRSA bacteremia included a diagnosis of cancer, presence of a central venous catheter, hyperglycemia (glucose level, >200 mg/dL), and infection with a MRSA strain carrying the gene for staphylococcal enterotoxin P (sep). Receipt of an anti-MRSA medication had a significant protective effect. Conclusions. In an analysis controlling for host factors, colonization with MRSA carrying sep increased the risk of MRSA bacteremia. Identification of risk-adjusted genetic determinants of virulence may help to improve prediction of invasive disease and suggest new targets for therapeutic intervention. PMID:24041793
Chong, Yong Pil; Park, Ki-Ho; Kim, Eun Sil; Kim, Mi-Na; Kim, Sung-Han; Lee, Sang-Oh; Choi, Sang-Ho; Jeong, Jin-Yong; Woo, Jun Hee
The prevalence of the heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) phenotype among methicillin-resistant S. aureus (MRSA) blood isolates can reach 38%. hVISA bacteremia is known to be associated with vancomycin treatment failure, including persistent bacteremia. We conducted this study to evaluate risk factors for 12-week mortality in patients with hVISA bacteremia through a detailed clinical and microbiological analysis of a prospective cohort of patients with S. aureus bacteremia. All isolates were collected on the first day of bacteremia and subjected to population analysis profiling for hVISA detection, genotyping, and PCR analysis for 39 virulence factors. Of 382 patient with MRSA bacteremia, 121 (32%) had hVISA bacteremia. Deceased patients were more likely to have hematologic malignancy (P = 0.033), ultimately or rapidly fatal disease (P = 0.007), and a higher Pitt bacteremia score (P = 0.010) than surviving patients. The sequence type 239 (ST239) clonal type and definitive linezolid treatment were associated with a trend toward reduced mortality (P = 0.061 and 0.072, respectively), but a high vancomycin MIC (≥2 mg/liter) was not associated with increased mortality (P = 0.368). In a multivariate analysis, ultimately or rapidly fatal disease (adjusted odds ratio [aOR], 2.80; 95% confidence interval [CI], 1.14 to 6.85) and a high Pitt bacteremia score (aOR, 1.26; 95% CI, 1.07 to 1.48) were independent risk factors for mortality. Hematologic malignancy was associated with a trend toward increased mortality (P = 0.094), and ST239 was associated with a trend toward reduced mortality (P = 0.095). Our study suggests that ST239 hVISA is a possible predictor of survival in hVISA bacteremia. PMID:25845875
Nielsen, Lise H; Jensen-Fangel, Søren; Benfield, Thomas;
BACKGROUND: Staphylococcus aureus is a leading cause of bloodstream infections among hemodialysis patients and of exit-site infections among peritoneal dialysis patients. However, the risk and prognosis of Staphylococcus aureus bacteremia among end-stage renal disease patients have not been...... delineated. METHODS: In this Danish nationwide, population-based cohort study patients with end-stage renal disease and matched population controls were observed from end-stage renal disease diagnosis/sampling until first episode of Staphylococcus aureus bacteremia, death, or end of study period....... Staphylococcus aureus positive blood cultures, hospitalization, comorbidity, and case fatality were obtained from nationwide microbiological, clinical, and administrative databases. Incidence rates and risk factors were assessed by regression analysis. RESULTS: The incidence rate of Staphylococcus aureus...
Jared A Greenberg
Full Text Available PURPOSE: The clinical implications for patients who survive serious infections are not well understood. It has been hypothesized that the excess mortality for survivors of sepsis observed in epidemiological studies is due to increased vulnerability to subsequent infections. We undertook this study to identify characteristics of patients who are at high risk for death after surviving a common type of blood-stream infection. MATERIALS AND METHODS: At a single academic medical center, 237 patients with Staphylococcus aureus bacteremia admitted during a three-year period were retrospectively identified. The primary outcomes were 30-day and 31 to 90-day mortality after the first positive blood culture. The primary predictor variable of interest was clinical immune dysfunction prior to bacteremia. RESULTS: The 30-day mortality was not significantly different for patients with and without prior immune dysfunction. However, during days 31 to 90, 11 patients (20% with prior immune dysfunction compared to 10 patients (8.6% without prior immune dysfunction died (OR 2.59, 95% CI 1.03-6.53, p = 0.04. In a Cox-proportional hazard model controlling for age, there was a significant association between prior immune dysfunction and greater 31 to 90 day mortality (HR 2.44, 95% CI 1.01-5.90, p = 0.05 and a non-significant trend towards occurrence of subsequent infections and greater 31 to 90 day mortality (HR 2.12, 95% CI 0.89-5.07, p = 0.09. CONCLUSIONS: Patients with prior immune dysfunction are at high risk for death 31 to 90 days, but not <30 days, after S. aureus bacteremia. Further investigation is needed to determine if this finding is due to poor prognosis of chronic disease or increased vulnerability to subsequent infections.
Gradel, Kim Oren; Nielsen, Stig Lønberg; Pedersen, Court
Seasonal variation analysis. METHODS In 3 Danish health regions (2.3 million total inhabitants), patients with bacteremia were identified from 2000 through 2011 using information from laboratory information systems. Analyses were confined to Escherichia coli, Staphylococcus aureus, and Streptococcus...... pneumoniae. Additional data were obtained from the Danish National Hospital Registry for the construction of admission histories and calculation of the Charlson comorbidity index (CCI). Bacteremias were categorized as community acquired, healthcare associated (HCA), and hospital acquired. We defined multiple....... coli, 6,924 S. aureus, and 4,884 S. pneumoniae bacteremia cases. For E. coli, the seasonal variation was highest for community-acquired cases (PTT ratio, 1.24; 95% CI, 1.17-1.32), was diminished for HCA (PTT ratio, 1.14; 95% CI, 1.04-1.25), and was missing for hospital-acquired cases. No seasonal...
McGregor Jessina C
Full Text Available Abstract Background The high prevalence of methicillin-resistant S. aureus (MRSA has led clinicians to select antibiotics that have coverage against MRSA, usually vancomycin, for empiric therapy for suspected staphylococcal infections. Clinicians often continue vancomycin started empirically even when methicillin-susceptible S. aureus (MSSA strains are identified by culture. However, vancomycin has been associated with poor outcomes such as nephrotoxicity, persistent bacteremia and treatment failure. The objective of this study was to compare the effectiveness of vancomycin versus the beta-lactam antibiotics nafcillin and cefazolin among patients with MSSA bacteremia. The outcome of interest for this study was 30-day in-hospital mortality. Methods This retrospective cohort study included all adult in-patients admitted to a tertiary-care facility between January 1, 2003 and June 30, 2007 who had a positive blood culture for MSSA and received nafcillin, cefazolin or vancomycin. Cox proportional hazard models were used to assess independent mortality hazards comparing nafcillin or cefazolin versus vancomycin. Similar methods were used to estimate the survival benefits of switching from vancomycin to nafcillin or cefazolin versus leaving patients on vancomycin. Each model included statistical adjustment using propensity scores which contained variables associated with an increased propensity to receive vancomycin. Results 267 patients were included; 14% (38/267 received nafcillin or cefazolin, 51% (135/267 received both vancomycin and either nafcillin or cefazolin, and 35% (94/267 received vancomycin. Thirty (11% died within 30 days. Those receiving nafcillin or cefazolin had 79% lower mortality hazards compared with those who received vancomycin alone (adjusted hazard ratio (HR: 0.21; 95% confidence interval (CI: 0.09, 0.47. Among the 122 patients who initially received vancomycin empirically, those who were switched to nafcillin or cefazolin (66
Sanne van den Berg
Full Text Available Proteomic studies with different Staphylococcus aureus isolates have shown that the cell surface-exposed and secreted proteins IsaA, LytM, Nuc, the propeptide of Atl (pro-Atl and four phenol-soluble modulins α (PSMα are invariantly produced by this pathogen. Therefore the present study was aimed at investigating whether these proteins can be used for active immunization against S. aureus infection in mouse models of bacteremia and skin infection. To this end, recombinant His-tagged fusions of IsaA, LytM, Nuc and pro-Atl were isolated from Lactococcus lactis or Escherichia coli, while the PSMα1-4 peptides were chemically synthesized. Importantly, patients colonized by S. aureus showed significant immunoglobulin G (IgG responses against all eight antigens. BALB/cBYJ mice were immunized subcutaneously with a mixture of the antigens at day one (5 μg each, and boosted twice (25 μg of each antigen with 28 days interval. This resulted in high IgG responses against all antigens although the response against pro-Atl was around one log lower compared to the other antigens. Compared to placebo-immunized mice, immunization with the octa-valent antigen mixture did not reduce the S. aureus isolate P load in blood, lungs, spleen, liver, and kidneys in a bacteremia model in which the animals were challenged for 14 days with a primary load of 3 × 10(5 CFU. Discomfort scores and animal survival rates over 14 days did not differ between immunized mice and placebo-immunized mice upon bacteremia with S. aureus USA300 (6 × 10(5 CFU. In addition, this immunization did not reduce the S. aureus isolate P load in mice with skin infection. These results show that the target antigens are immunogenic in both humans and mice, but in the used animal models do not result in protection against S. aureus infection.
Forsblom, E; Nurmi, A-M; Ruotsalainen, E; Järvinen, A
The purpose of this study was to examine the prognostic impact of corticosteroids in hemodynamically stabile Staphylococcus aureus bacteremia (SAB). There were 361 hemodynamically stabile methicillin-sensitive SAB patients with prospective follow-up and grouping according to time-point, dose and indication for corticosteroid therapy. To enable analyses without external interfering corticosteroid therapy all patients with corticosteroid therapy equivalent to prednisone >10 mg/day for ≥1 month prior to positive blood culture results were excluded. Twenty-five percent (92) of patients received corticosteroid therapy of which 11 % (40) had therapy initiated within 1 week (early initiation) and 9 % (31) had therapy initiated 2-4 weeks after (delayed initiation) positive blood culture. Twenty-one patients (6 %) had corticosteroid initiated after 4 weeks and were not included in the analyses. A total of 55 % (51/92) received a weekly prednisone dose >100 mg. Patients with early initiated corticosteroid therapy had higher mortality compared to patients treated without corticosteroid therapy at 28 days (20 % vs. 7 %) (OR, 3.11; 95%CI, 1.27-7.65; p corticosteroid therapy predicted 28-day (HR, 3.75; 95%CI, 1.60-8.79; p = 0.002) and 90-day (HR, 3.10; 95%CI, 1.50-6.39; p = 0.002) mortality in Cox proportional hazards regression analysis. When including only patients receiving early initiated corticosteroid therapy with prednisone ≥100 mg/week the negative prognostic impact on 28-day mortality was accentuated (HR 4.8, p = 0.001). Corticosteroid therapy initiation after 1 week of positive blood cultures had no independent prognostic impact. Early initiation of corticosteroid therapy may be associate to increased mortality in hemodynamically stabile SAB.
Schuch, Raymond; Lee, Han M; Schneider, Brent C; Sauve, Karen L; Law, Christina; Khan, Babar K; Rotolo, Jimmy A; Horiuchi, Yuki; Couto, Daniel E; Raz, Assaf; Fischetti, Vincent A; Huang, David B; Nowinski, Robert C; Wittekind, Michael
Lysins are bacteriophage-derived enzymes that degrade bacterial peptidoglycans. Lysin CF-301 is being developed to treat Staphylococcus aureus because of its potent, specific, and rapid bacteriolytic effects. It also demonstrates activity on drug-resistant strains, has a low resistance profile, eradicates biofilms, and acts synergistically with antibiotics. CF-301 was bacteriolytic against 250 S. aureus strains tested including 120 methicillin-resistant S. aureus (MRSA) isolates. In time-kill studies with 62 strains, CF-301 reduced S. aureus by 3-log10 within 30 minutes compared to 6-12 hours required by antibiotics. In bacteremia, CF-301 increased survival by reducing blood MRSA 100-fold within 1 hour. Combinations of CF-301 with vancomycin or daptomycin synergized in vitro and increased survival significantly in staphylococcal-induced bacteremia compared to treatment with antibiotics alone (P combinations with antibiotics was confirmed in 26 independent bacteremia studies. Combinations including CF-301 and antibiotics represent an attractive alternative to antibiotic monotherapies currently used to treat S. aureus bacteremia.
Li, Julius; Echevarria, Kelly L; Hughes, Darrel W; Cadena, Jose A; Bowling, Jason E; Lewis, James S
Contrary to prior case reports that described occasional clinical failures with cefazolin for methicillin-susceptible Staphylococcus aureus (MSSA) infections, recent studies have demonstrated no difference in outcomes between cefazolin and antistaphylococcal penicillins for the treatment of MSSA bacteremia. While promising, these studies described low frequencies of high-inoculum infections, such as endocarditis. This retrospective study compares clinical outcomes of cefazolin versus oxacillin for complicated MSSA bacteremia at two tertiary care hospitals between January 2008 and June 2012. Fifty-nine patients treated with cefazolin and 34 patients treated with oxacillin were included. Osteoarticular (41%) and endovascular (20%) sources were the predominant sites of infection. The rates of clinical cure at the end of therapy were similar between cefazolin and oxacillin (95% versus 88%; P=0.25), but overall failure at 90 days was higher in the oxacillin arm (47% versus 24%; P=0.04). Failures were more likely to have received surgical interventions (63% versus 40%; P=0.05) and to have an osteoarticular source (57% versus 33%; P=0.04). Failures also had a longer duration of bacteremia (7 versus 3 days; P=0.0002), which was the only predictor of failure. Antibiotic selection was not predictive of failure. Rates of adverse drug events were higher in the oxacillin arm (30% versus 3%; P=0.0006), and oxacillin was more frequently discontinued due to adverse drug events (21% versus 3%; P=0.01). Cefazolin appears similar to oxacillin for the treatment of complicated MSSA bacteremia but with significantly improved safety. The higher rates of failure with oxacillin may have been confounded by other patient factors and warrant further investigation.
Kreisel, Kristen M.; Stine, O. Colin; Johnson, J. Kristie; Perencevich, Eli N.; Shardell, Michelle D.; Lesse, Alan J.; Gordin, Fred M.; Climo, Michael W.; Roghmann, Mary-Claire
Objective USA300 methicillin-resistant Staphylococcus aureus (MRSA) is increasing as a cause of severe community-associated bacteremic infections. We assessed severe sepsis in response to infection in patients with USA300 MRSA compared to non-USA300 MRSA bacteremia. Methods A cohort study was conducted from 1997–2008 comparing sepsis in response to infection in 271 patients with MRSA bacteremia from four VA hospitals. Results Sixty-seven (25%) patients with MRSA bacteremia were USA300 MRSA; 204 (75%) were non-USA300 MRSA. The proportion of MRSA bacteremia caused by USA300 MRSA increased over time (χ2 p<0.0001). Adjusting for age and nosocomial infection, patients with USA300 MRSA bacteremia were more likely to have severe sepsis or septic shock in response to infection than patients with non-USA300 MRSA bacteremia (adjusted Relative Risk=1.82; 95% CI: 1.16–2.87; p=0.01). Conclusions This suggests that patients with USA300 MRSA are more likely to develop severe sepsis in response to their infection, which could be due to host or bacterial differences. PMID:21558047
Gotland, Nanja; Uhre, Marie-Louise; Mejer, N;
respiratory disease, nervous system disease, unknown causes, psychiatric disorders, cardiovascular disease and senility. Over time, rates of death decreased or were stable for all disease categories except for musculoskeletal and skin disease where a trend towards an increase was seen. CONCLUSION: Long......-term mortality after SAB was high but decreased over time. SAB cases were more likely to die of eight specific causes of death and less likely to die of five other causes of death compared to controls. Causes of death decreased for most disease categories. Risk factors associated with long-term mortality were......OBJECTIVES: Data describing long-term mortality in patients with Staphylococcus aureus bacteremia (SAB) is scarce. This study investigated risk factors, causes of death and temporal trends in long-term mortality associated with SAB. METHODS: Nationwide population-based matched cohort study...
Rasmussen, Rasmus V; Fowler, Vance G; Skov, Robert;
. Compounding this problem is the growing prevalence of methicillin-resistant S. aureus (MRSA) and the dwindling efficacy of vancomycin, long the treatment of choice for this pathogen. Despite the recent availability of several new antibiotics for S. aureus, new strategies for treatment and prevention...
Full Text Available One of the significant risk factor in the development of nosocomial Staphylococcal infections is bacteria Staphylococcus aureus (S. aureuscolonized in the nose of health personnel. The meticilin resistant S. aureus (MRSA was detected in the repeated blood cultures of two babies who had been followed for about 20 days in neonatal intensive care due to premature birth. Because of the failure to find the source in the assesment of the infants of whom MRSA reproduction continue, despite the appropriate treatment according to the results of antibiograms, examinations were performed fort he environment and the healtyh personnel. Cultures were taken from the total parenteral nutrition (TPN solution given to the babies. S. aureus growth was detected in the received culture. Therefore cultures were obtained from the places where there will be source in the division where TPN was prepared and nsal cultures were taken from the personnel. Because of growth of S. aureus only in the nasal cultures of the personnel, considering that the source was the personnel, the personnel were given the treatment of mupirocin pomad for five days, and during this period the work of the staff were replaced. There was not any growth in the TPN received at the and of the treatment an in the blood cultures of the patients. These facts showed us the necessity of making the necessary screening by considering the health personnel can also be the source in case of any S. aureus growth. [J Contemp Med 2016; 6(4.000: 382-384
S. van den Berg (Sanne); J.D. Laman (Jon); L. Boon (Louis); M.T. ten Kate (Marian); G.J. de Knegt (Gerjo); R.M. Verdijk (Robert); H.A. Verbrugh (Henri); J.L. Nouwen (Jan); I.A.J.M. Bakker-Woudenberg (Irma)
textabstractInvasive Staphylococcus aureus infections are frequently associated with bacteraemia. To support clinical decisions on antibiotic therapy, there is an urgent need for reliable markers as predictors of infection outcome. In the present study in mice, bacteraemia was established by intrave
Gradel, Kim Oren; Nielsen, Stig Lønberg; Pedersen, Court; Knudsen, Jenny Dahl; Østergaard, Christian; Arpi, Magnus; Jensen, Thøger Gorm; Kolmos, Hans Jørn; Søgaard, Mette; Lassen, Annmarie Touborg; Schønheyder, Henrik Carl
OBJECTIVE Seasonal variation is a characteristic of many infectious diseases, but relatively little is known about determinants thereof. We studied the impact of place of acquisition and patient characteristics on seasonal variation of bacteremia caused by the 3 most common pathogens. DESIGN Seasonal variation analysis. METHODS In 3 Danish health regions (2.3 million total inhabitants), patients with bacteremia were identified from 2000 through 2011 using information from laboratory information systems. Analyses were confined to Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Additional data were obtained from the Danish National Hospital Registry for the construction of admission histories and calculation of the Charlson comorbidity index (CCI). Bacteremias were categorized as community acquired, healthcare associated (HCA), and hospital acquired. We defined multiple subgroups by combining the following characteristics: species, acquisition, age group, gender, CCI level, and location of infection. Assuming a sinusoidal model, seasonal variation was assessed by the peak-to-trough (PTT) ratio with a 95% confidence interval (CI). RESULTS In total, we included 16,006 E. coli, 6,924 S. aureus, and 4,884 S. pneumoniae bacteremia cases. For E. coli, the seasonal variation was highest for community-acquired cases (PTT ratio, 1.24; 95% CI, 1.17-1.32), was diminished for HCA (PTT ratio, 1.14; 95% CI, 1.04-1.25), and was missing for hospital-acquired cases. No seasonal variation was observed for S. aureus. S. pneumoniae showed high seasonal variation, which did not differ according to acquisition (overall PTT ratio, 3.42; 95% CI, 3.10-3.83). CONCLUSIONS Seasonal variation was mainly related to the species although the place of acquisition was important for E. coli. Infect Control Hosp Epidemiol 2016;37:946-953.
Full Text Available When a Staphylococcus-like organism (SLO is microscopically found in Gram staining of blood culture (BC specimen, it seems reasonable to administrate a glycopeptide (GP for empirical therapy. The paper investigates the risk factors for 14-day mortality in patients with methicillin-resistance Staphylococcus aureus bacteremia (MRSAB and clarifies the impact of the timing for initiating GP therapy. A retrospective study identifies patients with MRSAB (endocarditis was excluded between 2006 and 2009. Patients were categorized as receiving GP at the interval before a preliminary BC report indicating the growth of SLO and the onward 24 hours or receiving GP 24 h after a preliminary BC report indicating the growth of SLO. Total 339 patients were enrolled. There was no difference on the 14-day overall or infection-related mortality rates at the time to administer GP. Multivariate analysis disclosed pneumonia (OR = 4.47; of 95% CI; of 2.09–9.58; and high APACHE II score (OR, 2.81, with 95% CI, 1.19–6.65; were independent risk factors for infection-related mortality. The mortality rate did not decrease following administrating GP immediately after a preliminary BC indicating SLO growth. An additional research for the optimal timing for initiating GP treatment is warranted.
Gudiol, Francisco; Aguado, José María; Pascual, Alvaro; Pujol, Miquel; Almirante, Benito; Miró, José María; Cercenado, Emilia; Domínguez, María de Los Angeles; Soriano, Alex; Rodríguez-Baño, Jesús; Vallés, Jordi; Palomar, Mercedes; Tornos, Pilar; Bouza, Emilio
Bacteremia and endocarditis due to methicillin-resistant Staphylococcus aureus (MRSA) are prevalent and clinically important. The rise in MRSA bacteremia and endocarditis is related with the increasing use of venous catheters and other vascular procedures. Glycopeptides have been the reference drugs for treating these infections. Unfortunately their activity is not completely satisfactory, particularly against MRSA strains with MICs > 1 microg/mL. The development of new antibiotics, such as linezolid and daptomycin, and the promise of future compounds (dalvabancin, ceftobiprole and telavancin) may change the expectatives in this field.The principal aim of this consensus document was to formulate several recommendations to improve the outcome of MRSA bacteremia and endocarditis, based on the latest reported scientific evidence. This document specifically analyzes the approach for three clinical situations: venous catheter-related bacteremia, persistent bacteremia, and infective endocarditis due to MRSA.
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA bacteremia was associated with high mortality, but the risk factors associated with mortality remain controversial.A retrospective cohort study was designed. All patients with MRSA bacteremia admitted were screened and collected for their clinical presentations and laboratory characteristics. Minimum inhibitory concentration (MIC and staphylococcal cassette chromosome mec (SCCmec type of bacterial isolates were determined. Risk factors for mortality were analyzed.Most MRSA isolates from the 189 enrolled patients showed reduced susceptibility to antibiotics, including MIC of vancomycin ≥ 1.5 mg/L (79.9%, teicoplanin ≥ 2 mg/L (86.2%, daptomycin ≥ 0.38 mg/L (73.0% and linezolid ≥ 1.5 mg/L (64.0%. MRSA with vancomycin MIC ≥ 1.5 mg/L and inappropriate initial therapy were the two most important risk factors for mortality (both P < 0.05; odds ratio = 7.88 and 6.78. Hospital-associated MRSA (HA-MRSA, carrying SCCmec type I, II, or III, was associated with reduced susceptibility to vancomycin, teicoplanin or daptomycin and also with higher attributable mortality (all P < 0.05. Creeping vancomycin MIC was linked to higher MIC of teicoplanin and daptomycin (both P < 0.001, but not linezolid (P = 0.759.Giving empirical broad-spectrum antibiotics for at least 5 days to treat catheter-related infections, pneumonia, soft tissue infection and other infections was the most important risk factor for acquiring subsequent HA-MRSA infection. Choice of effective anti-MRSA agents for treating MRSA bacteremia should be based on MIC of vancomycin, teicoplanin and daptomycin. Initiation of an effective anti-MRSA agent without elevated MIC in 2 days is crucial for reducing mortality.
van den Berg, Sanne; Koedijk, Dennis G. A. M.; Back, Jaap Willem; Neef, Jolanda; Dreisbach, Annette; van Dijl, Jan Maarten; Bakker-Woudenberg, Irma A. J. M.; Buist, Girbe
Proteomic studies with different Staphylococcus aureus isolates have shown that the cell surface-exposed and secreted proteins IsaA, LytM, Nuc, the propeptide of Atl (pro-Atl) and four phenol-soluble modulins alpha (PSM alpha) are invariantly produced by this pathogen. Therefore the present study wa
Van Den Berg, S. (Sanne); Koedijk, D.G.A.M. (Dennis G. A. M.); Back, J.W. (Jaap Willem); J. Neef (Jolanda); A. Dreisbach (Annette); J.M. Dijl (Jan Maarten); I.A.J.M. Bakker-Woudenberg (Irma); G. Buist (Girbe)
textabstractProteomic studies with different Staphylococcus aureus isolates have shown that the cell surface-exposed and secreted proteins IsaA, LytM, Nuc, the propeptide of Atl (pro-Atl) and four phenol-soluble modulins α (PSMα) are invariantly produced by this pathogen. Therefore the present study
Shiba, Mikio; Maeda, Hideaki; Shiono, Motomi
A 40-year-old man underwent ascending aorta replacement for an acute type A aortic dissection. After the operations, methicillin-resistant Staphylococcus aureus was identified in sputum and blood cultures. Although anti-methicillin-resistant Staphylococcus aureus drugs were administered, most of the intermittent blood cultures remained positive. The focus of methicillin-resistant Staphylococcus aureus infection was not evident in the early stages, and no specific symptoms such as abscess or endocarditis were observed. However, abscesses in the brain, mediastinum and spleen were found 3 years after the operation. The minimum inhibitory concentration of vancomycin gradually increased from 1 to 4 µg/mL during the course of treatment. This case provides evidence for a potential role of combination therapy. PMID:27489691
Full Text Available A 40-year-old man underwent ascending aorta replacement for an acute type A aortic dissection. After the operations, methicillin-resistant Staphylococcus aureus was identified in sputum and blood cultures. Although anti-methicillin-resistant Staphylococcus aureus drugs were administered, most of the intermittent blood cultures remained positive. The focus of methicillin-resistant Staphylococcus aureus infection was not evident in the early stages, and no specific symptoms such as abscess or endocarditis were observed. However, abscesses in the brain, mediastinum and spleen were found 3 years after the operation. The minimum inhibitory concentration of vancomycin gradually increased from 1 to 4 µg/mL during the course of treatment. This case provides evidence for a potential role of combination therapy.
Characterization of alpha-toxin hla gene variants, alpha-toxin expression levels, and levels of antibody to alpha-toxin in hemodialysis and postsurgical patients with Staphylococcus aureus bacteremia.
Sharma-Kuinkel, Batu K; Wu, Yuling; Tabor, David E; Mok, Hoyin; Sellman, Bret R; Jenkins, Amy; Yu, Li; Jafri, Hasan S; Rude, Thomas H; Ruffin, Felicia; Schell, Wiley A; Park, Lawrence P; Yan, Qin; Thaden, Joshua T; Messina, Julia A; Fowler, Vance G; Esser, Mark T
Alpha-toxin is a major Staphylococcus aureus virulence factor. This study evaluated potential relationships between in vitro alpha-toxin expression of S. aureus bloodstream isolates, anti-alpha-toxin antibody in serum of patients with S. aureus bacteremia (SAB), and clinical outcomes in 100 hemodialysis and 100 postsurgical SAB patients. Isolates underwent spa typing and hla sequencing. Serum anti-alpha-toxin IgG and neutralizing antibody levels were measured by using an enzyme-linked immunosorbent assay and a red blood cell (RBC)-based hemolysis neutralization assay. Neutralization of alpha-toxin by an anti-alpha-toxin monoclonal antibody (MAb MEDI4893) was tested in an RBC-based lysis assay. Most isolates encoded hla (197/200; 98.5%) and expressed alpha-toxin (173/200; 86.5%). In vitro alpha-toxin levels were inversely associated with survival (cure, 2.19 μg/ml, versus failure, 1.09 μg/ml; P toxin-expressing S. aureus isolates (P toxin is highly conserved in clinical S. aureus isolates. Higher in vitro alpha-toxin levels were associated with a positive clinical outcome. Although patients infected with alpha-toxin-producing S. aureus exhibited higher anti-alpha-toxin antibody levels, these levels were not associated with a better clinical outcome in this study.
Michael Z David
Full Text Available BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA strains have become common causes of skin and soft tissue infections (SSTI among previously healthy people, a role of methicillin-susceptible (MSSA isolates before the mid-1990s. We hypothesized that, as MRSA infections became more common among S. aureus infections in the community, perhaps MSSA infections had become more important as a cause of healthcare-associated infection. METHODS: We compared patients, including children and adults, with MRSA and MSSA infections at the University of Chicago Medical Center (UCMC from all clinical units from July 1, 2004-June 30, 2005; we also compared the genotypes of the MRSA and MSSA infecting bacterial strains. RESULTS: Compared with MRSA patients, MSSA patients were more likely on bivariate analysis to have bacteremia, endocarditis, or sepsis (p = 0.03, to be an adult (p = 0.005, to be in the intensive care unit (21.9% vs. 15.6% or another inpatient unit (45.6% vs. 40.7% at the time of culture. MRSA (346/545 and MSSA (76/114 patients did not differ significantly in the proportion classified as HA-S. aureus by the CDC CA-MRSA definition (p = 0.5. The genetic backgrounds of MRSA and MSSA multilocus sequence type (ST 1, ST5, ST8, ST30, and ST59 comprised in combination 94.5% of MRSA isolates and 50.9% of MSSA isolates. By logistic regression, being cared for in the Emergency Department (OR 4.6, CI 1.5-14.0, p = 0.008 was associated with MRSA infection. CONCLUSION: Patients with MSSA at UCMC have characteristics consistent with a health-care-associated infection more often than do patients with MRSA; a possible role reversal has occurred for MSSA and MRSA strains. Clinical MSSA and MRSA strains shared genotype backgrounds.
J.P. Steinberg; C.C. Clarke; B.O. Hackman
textabstractThe rate of nosocomial bacteremia due to Staphylococcus aureus has increased over the past decade, but trends in community-acquired S. aureus bacteremia are less certain. This hospital-based observational study compares nosocomial and community-acquired S. aureus bacteremias during 1980-
Subhankari Prasad Chakraborty; Santanu Kar Mahapatra; Sumanta Kumar Sahu; Sourav Chattopadhyay; Panchanan Pramanik; Somenath Roy
Objective:To test the survival ofStaphylococcus aureus (S. aureus) inside lymphocyte that contributes to the pathogenesis of infection and possible anti-inflammatory and antioxidative effect of nanoconjugated vancomycin againstin vivo S. aureus infection in a dose and duration dependent manner.Methods:5×106CFU/mL vancomycin-sensitive S. aureus(VSSA) and vancomycin-resistiveS. aureus (VRSA) were challenged in Swiss male mice for3 days,5 days, 10 days and15days, respectively. Bacteremia and inflammatory parameters were observed to evaluate the duration for development ofVSSA andVRSA infection.100mg/kg bw/day and500 mg/kg bw/day nanoconjugated vancomycin were administrated toVSSA andVRSA infected group for5days. Bacteremia, inflammatory parameters and oxidative stress related parameters were tested to observe the effective dose of nanoconjugated vancomycin againstVSSAandVRSA infection. Nanoconjugated vancomycin was treated at a dose of100 mg/kg bw/day and500 mg/kg bw/day, respectively, toVSSA andVRSA infected group for successive5 days,10 days and 15 days. Bacteremia, inflammatory parameters and oxidative stress related parameters were observed to assess the effective duration of nanoconjugated vancomycin againstVSSAand VRSA infection.Results: The result revealed thatin vivoVSSA andVRSA infection developed after 5 days of challenge by elevating theNO generation in lymphocyte and serum inflammatory markers. Administration with nanoconjugated vancomycin toVSSA andVRSA infected group at a dose of100 mg/kg bw/day and500 mg/kg bw/day, respectively, for successive10 days eliminated bacterimia, decreasedNO generation in lymphocyte, serum inflammatory markers and increased antioxidant enzyme status.Conclusions:These findings suggest,in vivochallenge ofVSSA andVRSA for5 days can produce the highest degree of damage in lymphocyte which can be ameliorated by treatment with nanoconjugated vancomycin for10 successive days.
N.J. Verkaik (Nelianne); C.P. de Vogel (Corné); H.A.M. Boelens (Hélène); D. Grumann (Dorothee); T. Hoogenboezem (Theo); C. Vink (Cornelis); H. Hooijkaas (Herbert); T.J. Foster (Timothy); H.A. Verbrugh (Henri); A.F. van Belkum (Alex); W.J.B. van Wamel (Willem)
textabstractBACKGROUND. Persistent carriers have a higher risk of Staphylococcus aureus infections than noncarriers but a lower risk of bacteremia-related death. Here, the role played by anti-staphylococcal antibodies was studied. METHODS. Serum samples from 15 persistent carriers and 19 noncarriers
Huttunen, Reetta; Hurme, Mikko; Laine, Janne; Eklund, Carita; Vuento, Risto; Aittoniemi, Janne; Huhtala, Heini; Syrjänen, Jaana
Nitric oxide (NO) as a vasoactive substance is a crucial element in the pathogenesis of sepsis. Endothelial NO synthase (eNOS) is, in turn, a key regulator of vascular NO production. The eNOS gene polymorphism at position 894 (G>T, Glu298Asp) resulting in T allele has been studied in the context of vascular diseases, but its role in sepsis has not yet been explored. We here studied the effect of eNOS Glu298Asp polymorphism on the clinical course of the disease in patients with bacteremia. The study comprised 147 patients with bacteremia caused by Staphylococcus aureus, Streptococcus pneumoniae, beta-hemolytic streptococci, or Escherichia coli. Laboratory findings and clinical data were registered on admission and during 6 consecutive days. The polymorphism of eNOS gene, G894T, was genotyped. Carriage of the T allele was associated with low MAP (P = 0.004) and high Sequential Organ Failure Assessment score (P = 0.001) in patients with E. coli bacteremia. The effect on blood pressure was most prominent in the early stage of the disease (MAP on admission = 52 mmHg in T-allele carriers vs. 91 mmHg in noncarriers; P < 0.001). However, the same was not detected in bacteremia caused by a gram-positive organism (S. aureus, S. pneumoniae, or beta-hemolytic streptococci). The Glu298Asp polymorphism had no effect on case fatality in any pathogen. Carriage of the T allele of the eNOS gene is a risk factor for hypotension in patients with E. coli bacteremia but not in bacteremia caused by a gram-positive organism.
Kwiecinski, Jakub; Jin, Tao; Josefsson, Elisabet
Staphylococcus aureus is the most common cause of skin infections that range from mild diseases up to life-threatening conditions. Mechanisms of S. aureus virulence in those infections remain poorly studied. To investigate the impact of S. aureus surface proteins on skin infection, we used mouse models of skin abscess formation and skin necrosis, induced by a subcutaneous injection of bacteria. In the skin abscess model, a sortase-deficient S. aureus strain lacking all of its cell-wall anchored proteins was less virulent than its wild-type strain. Also, strains specifically lacking protein A, fibronecting binding proteins, clumping factor A or surface protein SasF were impaired in their virulence. When a model of dermonecrosis was studied, the S. aureus surface proteins could not be shown to be involved. In summary, surface proteins play an important role in virulence of S. aureus skin abscess infections, but not in formation of skin necrosis.
Suzuki, K; Tagami, K
Among athletes, Staphylococcus aureus is thought to be transmitted by close physical contact with carriers. Nevertheless, evidence is limited with regard to both the tracking of individual strains and the role of S. aureus on the skin's surface. We investigated its transmission using molecular genotyping and the presence of S. aureus on the skin during exercise. In the first study, nasal samples were obtained from 172 athletes over a period of up to one year. The 200 strains of S. aureus collected from these athletes were genotyped, and transmission of S. aureus was detected by phage open reading frame typing (POT). In the second study, the presence of S. aureus on the skin's surface was compared between nasal carriers (n=9) and non-nasal carriers (n=9), who had participated in the first study. In the first study, 10 cases of transmission were confirmed. In the second study, exercise-induced sweating increased S. aureus isolates from the skin's surface (before vs. after exercise: 5.2±5.4 vs. 41.7±40.6 CFU/ml) in nasal carriers. In 5 of 9 nasal carriers, S. aureus isolates from the skin's surface were clonally identical to those from the nares. These results identify a major route of S. aureus transmission among athletes and provide insight into the role played by exercise-induced sweating in nasal carriers.
Marlieke E A de Kraker
Full Text Available BACKGROUND: The relative importance of human diseases is conventionally assessed by cause-specific mortality, morbidity, and economic impact. Current estimates for infections caused by antibiotic-resistant bacteria are not sufficiently supported by quantitative empirical data. This study determined the excess number of deaths, bed-days, and hospital costs associated with blood stream infections (BSIs caused by methicillin-resistant Staphylococcus aureus (MRSA and third-generation cephalosporin-resistant Escherichia coli (G3CREC in 31 countries that participated in the European Antimicrobial Resistance Surveillance System (EARSS. METHODS AND FINDINGS: The number of BSIs caused by MRSA and G3CREC was extrapolated from EARSS prevalence data and national health care statistics. Prospective cohort studies, carried out in hospitals participating in EARSS in 2007, provided the parameters for estimating the excess 30-d mortality and hospital stay associated with BSIs caused by either MRSA or G3CREC. Hospital expenditure was derived from a publicly available cost model. Trends established by EARSS were used to determine the trajectories for MRSA and G3CREC prevalence until 2015. In 2007, 27,711 episodes of MRSA BSIs were associated with 5,503 excess deaths and 255,683 excess hospital days in the participating countries, whereas 15,183 episodes of G3CREC BSIs were associated with 2,712 excess deaths and 120,065 extra hospital days. The total costs attributable to excess hospital stays for MRSA and G3CREC BSIs were 44.0 and 18.1 million Euros (63.1 and 29.7 million international dollars, respectively. Based on prevailing trends, the number of BSIs caused by G3CREC is likely to rapidly increase, outnumbering the number of MRSA BSIs in the near future. CONCLUSIONS: Excess mortality associated with BSIs caused by MRSA and G3CREC is significant, and the prolongation of hospital stay imposes a considerable burden on health care systems. A foreseeable shift in
Haristoy, X.; Lozniewski, A.; Tram, C.; Simeon, D.; Bevanger, L.; Lion, C.
Bacteremia caused by Francisella tularensis is rare and has been reported mainly in the United States and infrequently in Europe. We report herein the first case of bacteremic F. tularensis pneumonia in an immunocompetent individual in southern Europe. PMID:12791928
Parino, Eduardo; Mulinaris, Eric; Saccomano, Edgardo; Gallo, Juan Cruz; Kohan, Gabriel
A 34-year-old female patient presented with fever and right flank pain ten days after uncomplicated vaginal delivery. CT examination revealed right ovarian vein thrombosis and methicillin-resistant Staphylococcus aureus (MRSA) was isolated from blood cultures. No other source of bacteremia was found. Antibiotic therapy and anticoagulation with enoxaparin were instituted. Fourteen days after admission, she was discharged in good condition. Although a very uncommon complication after spontaneous vaginal delivery, septic ovarian vein thrombophlebitis should be suspected in cases of persistent puerperal fever when other diagnostic possibilities have been excluded. PMID:26221549
Full Text Available Infection of foot ulcers is a common, often severe and costly complication in diabetes. Diabetic foot infections (DFI are mainly polymicrobial, and Staphylococcus aureus is the most frequent pathogen isolated. The numerous virulence factors and toxins produced by S. aureus during an infection are well characterized. However, some particular features could be observed in DFI. The aim of this review is to describe the role of S. aureus in DFI and the implication of its toxins in the establishment of the infection. Studies on this issue have helped to distinguish two S. aureus populations in DFI: toxinogenic S. aureus strains (harboring exfoliatin-, EDIN-, PVL- or TSST-encoding genes and non-toxinogenic strains. Toxinogenic strains are often present in infections with a more severe grade and systemic impact, whereas non-toxinogenic strains seem to remain localized in deep structures and bone involving diabetic foot osteomyelitis. Testing the virulence profile of bacteria seems to be a promising way to predict the behavior of S. aureus in the chronic wounds.
Christensen, J S; Jensen, T G; Kolmos, H J
We conducted a hospital-based cohort study among adult patients with first-time Streptococcus pneumoniae bacteremia (SPB) from 2000 through 2008. Patients were identified in a population-based bacteremia database and followed up for mortality through the Danish Civil Registration System (CRS...... age of the patients was 65 years. The focal diagnosis of the SPB was pneumonia in 381 (79 %) patients, followed in frequency by meningitis in 33 (7 %) patients. Of the 481 patients, 390 (81 %) had community-acquired SPB. Of these, 23 (6 %) did not have sepsis, 132 (34 %) had sepsis, 224 (57 %) had...
Full Text Available Staphylococcus aureus is one of the most common pathogens causing keratitis. Surfactant protein D (SP-D plays a critical role in host defense and innate immunity. In order to investigate the role of SP-D in ocular S. aureus infection, the eyes of wild-type (WT and SP-D knockout (SP-D KO C57BL/6 mice were infected with S. aureus (10(7 CFU/eye in the presence and absence of cysteine protease inhibitor(E64.Bacterial counts in the ocular surface were examined 3, 6, 12, 24 hrs after infection. Bacterial phagocytosis by neutrophils and bacterial invasion in ocular epithelial cells were evaluated quantitatively. S. aureus-induced ocular injury was determined with corneal fluorescein staining. The results demonstrated that SP-D is expressed in ocular surface epithelium and the lacrimal gland; WT mice had increased clearance of S. aureus from the ocular surface (p<0.05 and reduced ocular injury compared with SP-D KO mice. The protective effects of SP-D include increased bacterial phagocytosis by neutrophils (p<0.05 and decreased bacterial invasion into epithelial cells (p<0.05 in WT mice compared to in SP-D KO mice. In the presence of inhibitor (E64, WT mice showed enhanced bacterial clearance (p<0.05 and reduced ocular injury compared to absent E64 while SP-D KO mice did not. Collectively, we concluded that SP-D protects the ocular surface from S. aureus infection but cysteine protease impairs SP-D function in this murine model, and that cysteine protease inhibitor may be a potential therapeutic agent in S. aureus keratitis.
Feng, Bai-Sui; He, Shao-Heng; Zheng, Peng-Yuan; Wu, Linda; Yang, Ping-Chang
Bacterium-induced diarrhea results in 2 to 2.5 million deaths in the world each year. The mechanism needs to be further understood. Staphylococcus aureus infection has a close relation with diarrhea; its cell wall component peptidoglycan (PGN) has strong biological activity on immune cells and possibly plays a role in S. aureus-induced diarrhea. The present study showed that oral PGN-induced diarrhea in mice in a dose-dependent manner. Intestinal epithelial cells absorbed PGN via the intracel...
Rubinstien, E; Slavin, J
We describe a geriatric patient with acute substernal chest pain thought to be due to coronary heart disease, who was subsequently found to have Staphylococcus aureus bacteremia associated with infection of the thymus and manubriosternal joint. To our knowledge, this is the first report of (1) a thymic abscess in a geriatric patient, (2) a thymic abscess associated with bacteremia, (3) extra-articular extension of manubriosternal pyarthrosis, and (4) manubriosternal pyarthrosis in the geriatric age group.
Full Text Available Chronic infections with Staphylococcus aureus such as septicemia, osteomyelitis, endocarditis, and biofilm infections are difficult to treat because of persisters. Despite many efforts in understanding bacterial persistence, the mechanisms of persister formation in S. aureus remain elusive. Here, we performed a genome-wide screen of a transposon mutant library to study the molecular mechanisms involved in persistence of community-acquired S. aureus. Screening of the library for mutants defective in persistence or tolerance to rifampicin revealed many genes involved in metabolic pathways that are important for antibiotic persistence. In particular, the identified mutants belonged to metabolic pathways involved in carbohydrate, amino acid, lipid, vitamin and purine biosynthesis. Five mutants played a role in purine biosynthesis and two mutants, purB, an adenylosuccinate lyase, and purM, a phosphoribosylaminoimidazole synthetase, were selected for further confirmation. Mutants purB and purM showed defective persistence compared to the parental strain USA300 in multiple stress conditions including various antibiotics, low pH, and heat stress. The defect in persistence was restored by complementation with the wildtype purB and purM gene in the respective mutants. These findings provide new insights into the mechanisms of persistence in S. aureus and provide novel therapeutic targets for developing more effective treatment for persistent infections due to S. aureus.
Nielsen, Stig Lønberg
incidence rates decreased for Escherichia coli, Staphylococcus aureus, co-agulase-negative staphylococci and Streptococcus pneumoniae, and increased for Pseudomonas aeruginosa and enterococci species (pincidence of 14.2 per 1000 admissions and 23.6 per 10,000 bed days; highest for males, elderly individuals (> 65 years), and patients initially admitted to the Departments of Hematology, Nephrology, Internal Medicine, Urology or Oncology. The daily incidence was highest on the day of admission and declined rapidly to a low level on Day 3-7. Hereafter it increased steadily until Day 12 followed by more or less constant daily incidences. The daily incidences varied considerably with patient and clinical characteristics. Study III: In a population-based cohort study, we included 7783 patients with first-time bacteremia and 38,906 population controls matched on sex, year of birth and residency. We found that the cumulative mortality in bacteremia patients and population controls was 22.0% vs. 0.2% (30 days), 41.4% vs. 2.6% (1 year), and 75.8% vs. 36.6% (10 years). Bacteremia patients were consistently at increased risk of death compared with population controls throughout 12 years of follow-up and the risk of death remained 2-fold increased even among 5-year survivors of bacteremia (adjusted MRR: 2.1; 95% CI: 1.8-2.3). The most common causes of death after bacteremia were cancer and cardiovascular diseases. Compared with population controls, bacteremia patients were at the highest risk of death from genitourinary diseases and infectious diseases within 1 year of bacteremia. Among 1-year survivors of bacteremia, the risk of death was increased for all major causes of death compared with population controls. We conclude that the occurrence of bacteremia is decreasing in the general population. However, bacteremia is associated with a very poor short- and long-term prognosis and the risk of death remains increased for years compared with the general population. The most common
Nielsen, Stig Lønberg; Pedersen, C; Jensen, T G;
BACKGROUND: Numerous studies have shown that the incidence rate of bacteremia has been increasing over time. However, few studies have distinguished between community-acquired, healthcare-associated and nosocomial bacteremia. METHODS: We conducted a population-based study among adults with first......-acquired, 50.0 for healthcare-associated and 66.7 for nosocomial bacteremia. During 2000-2008, the overall incidence rate decreased by 23.3% from 254.1 to 198.8 (3.3% annually, p ...) and the incidence rate of nosocomial bacteremia decreased by 28.9% from 82.2 to 56.0 (4.2% annually, p
Navratna, Vikas; Nadig, Savitha; Sood, Varun; Prasad, K; Arakere, Gayathri; Gopal, B
Penicillin binding proteins (PBPs) are membrane-associated proteins that catalyze the final step of murein biosynthesis. These proteins function as either transpeptidases or carboxypeptidases and in a few cases demonstrate transglycosylase activity. Both transpeptidase and carboxypeptidase activities of PBPs occur at the D-Ala-D-Ala terminus of a murein precursor containing a disaccharide pentapeptide comprising N-acetylglucosamine and N-acetyl-muramic acid-L-Ala-D-Glu-L-Lys-D-Ala-D-Ala. Beta-lactam antibiotics inhibit these enzymes by competing with the pentapeptide precursor for binding to the active site of the enzyme. Here we describe the crystal structure, biochemical characteristics, and expression profile of PBP4, a low-molecular-mass PBP from Staphylococcus aureus strain COL. The crystal structures of PBP4-antibiotic complexes reported here were determined by molecular replacement, using the atomic coordinates deposited by the New York Structural Genomics Consortium. While the pbp4 gene is not essential for the viability of S. aureus, the knockout phenotype of this gene is characterized by a marked reduction in cross-linked muropeptide and increased vancomycin resistance. Unlike other PBPs, we note that expression of PBP4 was not substantially altered under different experimental conditions, nor did it change across representative hospital- or community-associated strains of S. aureus that were examined. In vitro data on purified recombinant S. aureus PBP4 suggest that it is a beta-lactamase and is not trapped as an acyl intermediate with beta-lactam antibiotics. Put together, the expression analysis and biochemical features of PBP4 provide a framework for understanding the function of this protein in S. aureus and its role in antimicrobial resistance.
Demirdal, Tuna; Demirturk, Nese; Cetinkaya, Zafer; Tufan, Gulnihal
In this retrospective study, the investigators examined blood cultures from patients that had been diagnosed with bacteremias over a 3-y period. The study was conduced at Kocatepe University Hospital (Middle Anatolia, Turkey). Blood samples that arrived at the university's microbiology laboratory between 2002 and 2005 were evaluated retrospectively. These samples were classified as contamination, false positivity, community-acquired bacteremia (CAB), or hospital-acquired bacteremia (HAB). Patient age and sex, foci of bacteremia, present comorbidities, predisposing factors, pathogens, and mortality rates were evaluated. A total of 1783 blood cultures that had been drawn from 1441 patients during this 3-y period were examined retrospectively. Of 354 positive isolates, 61 (17.2%) were CABs and 293 (82.8%) were HABs. In HABs, the most commonly isolated microorganisms were Staphylococcus aureus (37.5%), coagulase-negative staphylococci (29.7%), and Escherichia coli (10.2%); in CABs, the most commonly isolated microorganisms were S aureus (29.5%), Brucella spp (26.2%), and E coli (24.6%). Crude mortality rates were determined to be 15.2% for HABs and 12.7% for CABs. This study yielded data on the most common foci of bacteremia, microbiologic factors, and the epidemiology associated with HABs and CABs. It is hoped that these data will enhance empirical antibiotic therapeutic approaches, thereby preventing delays in treatment and decreasing mortality rates associated with bacteremias.
von Hoven, Gisela; Rivas, Amable J; Neukirch, Claudia; Klein, Stefan; Hamm, Christian; Qin, Qianqian; Meyenburg, Martina; Füser, Sabine; Saftig, Paul; Hellmann, Nadja; Postina, Rolf; Husmann, Matthias
Staphylococcus aureus is a leading cause of bacterial infections in humans, including life-threatening diseases such as pneumonia and sepsis. Its small membrane-pore-forming α-toxin is considered an important virulence factor. By destroying cell-cell contacts through cleavage of cadherins, the metalloproteinase ADAM10 (a disintegrin and metalloproteinase 10) critically contributes to α-toxin-dependent pathology of experimental S. aureus infections in mice. Moreover, ADAM10 was proposed to be a receptor for α-toxin. However, it is unclear whether the catalytic activity or specific domains of ADAM10 are involved in mediating binding and/or subsequent cytotoxicity of α-toxin. Also, it is not known how α-toxin triggers ADAM10's enzymatic activity, and whether ADAM10 is invariably required for all α-toxin action on cells. In the present study, we show that efficient cleavage of the ADAM10 substrate epithelial cadherin (E-cadherin) requires supra-cytotoxic concentrations of α-toxin, leading to significant increases in intracellular [Ca(2+)]; the fall in cellular ATP levels, typically following membrane perforation, became observable at far lower concentrations. Surprisingly, ADAM10 was dispensable for α-toxin-dependent xenophagic targeting of S. aureus, whereas a role for α-toxin attack on the plasma membrane was confirmed. The catalytic site of ADAM10, furin cleavage site, cysteine switch and intracellular domain of ADAM10 were not required for α-toxin binding and subsequent cytotoxicity. In contrast, an essential role for the disintegrin domain and the prodomain emerged. Thus, co-expression of the prodomain with prodomain-deficient ADAM10 reconstituted binding of α-toxin and susceptibility of ADAM10-deficient cells. The results of the present study may help to inform structural analyses of α-toxin-ADAM10 interactions and to design novel strategies to counteract S. aureus α-toxin action.
De Luca, Concetta; Mancin, Annalisa; Calabrò, Maria; Daleno, Cristina; Ferrario, Antonella; Renzulli, Raffaella; Scuderi, Cristina; Casari, Erminia
We report a case of Helicobacter pylori transient bacteremia in a woman with ulcerated antral gastric cancer. The patient was hospitalized for laparoscopy and subtotal gastrectomy. After surgery she developed fever (39°C) and was empirically treated with levofloxacin. Blood cultures, collected and sent immediately to Laboratory, were positive for a spiral Gram-negative bacterium. This isolate was identified as H. pylori and the specific susceptibility test was performed. One day after the fever was decreased but antibiotic treatment with levofloxacin was continued and it was maintained until discharge. In summary, H. pylori transient bacteremia may occur as a rare complication after stomach surgery. Further studies are necessary to elucidate the potential role of Helicobacter pylori presence in blood.
Pardo-Seco, Jacobo; Gómez-Carballa, Alberto; Martinón-Torres, Nazareth; Martinón-Sánchez, José María; Justicia-Grande, Antonio; Rivero-Calle, Irene; Pinnock, Elli; Salas, Antonio; Fink, Colin
Background The risk of bacteremia is considered low in children with acute bronchiolitis. However the rate of occult bacteremia in infants with RSV infection is not well established. The aim was to determine the actual rate and predictive factors of bacteremia in children admitted to hospital due to confirmed RSV acute respiratory illness (ARI), using both conventional culture and molecular techniques. Methods A prospective multicenter study (GENDRES-network) was conducted between 2011–2013 in children under the age of two admitted to hospital because of an ARI. Among those RSV-positive, bacterial presence in blood was assessed using PCR for Meningococcus, Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, in addition to conventional cultures. Results 66 children with positive RSV respiratory illness were included. In 10.6% patients, bacterial presence was detected: H. influenzae (n = 4) and S. pneumoniae (n = 2). In those patients with bacteremia, there was a previous suspicion of bacterial superinfection and had received empirical antibiotic treatment 6 out of 7 (85.7%) patients. There were significant differences in terms of severity between children with positive bacterial PCR and those with negative results: PICU admission (100% vs. 50%, P-value = 0.015); respiratory support necessity (100% vs. 18.6%, P-value < 0.001); Wood-Downes score (mean = 8.7 vs. 4.8 points, P-value < 0.001); GENVIP scale (mean = 17 vs. 10.1, P-value < 0.001); and length of hospitalization (mean = 12.1 vs. 7.5 days, P-value = 0.007). Conclusion Bacteremia is not frequent in infants hospitalized with RSV respiratory infection, however, it should be considered in the most severe cases. PMID:26872131
Bukowski, Michal; Lyzen, Robert; Helbin, Weronika M; Bonar, Emilia; Szalewska-Palasz, Agnieszka; Wegrzyn, Grzegorz; Dubin, Grzegorz; Dubin, Adam; Wladyka, Benedykt
Toxin-antitoxin systems were shown to be involved in plasmid maintenance when they were initially discovered, but other roles have been demonstrated since. Here we identify and characterize a novel toxin-antitoxin system (pemIKSa) located on Staphylococcus aureus plasmid pCH91. The toxin (PemKSa) is a sequence-specific endoribonuclease recognizing the tetrad sequence U↓AUU, and the antitoxin (PemISa) inhibits toxin activity by physical interaction. Although the toxin-antitoxin system is responsible for stable plasmid maintenance our data suggest the participation of pemIKSa in global regulation of staphylococcal virulence by alteration of the translation of large pools of genes. We propose a common mechanism of reversible activation of toxin-antitoxin systems based on antitoxin transcript resistance to toxin cleavage. Elucidation of this mechanism is particularly interesting because reversible activation is a prerequisite for the proposed general regulatory role of toxin-antitoxin systems.
Adriana Oliveira Guilarde
Full Text Available OBJETIVO: Avaliar a incidência de bacteremias, seu perfil de suscetibilidade antimicrobiana, e fatores associados ao óbito, em hospital universitário, no período de 1º de janeiro de 2000 a 31 de dezembro de 2001. MÉTODOS: Coorte retrospectiva. Pacientes maiores de 1 ano de idade, com bacteremia laboratorialmente confirmada e clinicamente significativa foram incluídos no estudo. Realizada análise de sobrevida multivariada, seguindo o modelo de riscos proporcionais de Cox. RESULTADOS: Foram detectados 295 episódios de bacteremia. O patógeno mais freqüente foi o Staphylococcus aureus: 118 (40%, com 55,9% de MRSA. A letalidade pela bacteremia foi de 34,5%. Os fatores de risco independentes para o óbito foram terapia inicial inadequada (HR ajustado 2,05 IC 95%: 1,25-3,36 e gravidade da apresentação clínica (HR ajustado 5,52 IC 95%: 3,15-9,69. CONCLUSÃO: Nosso estudo mostrou elevada letalidade associada a bacteremia, com alta freqüência de MRSA. A terapia inicial inadequada e a gravidade da apresentação clínica foram fatores de risco independentes para o óbito pela bacteremia.OBJECTIVE: To evaluate the frequency and profile of bacteremia, its antimicrobial susceptibility and to analyze predictors of mortality in bloodstream infections (BSI at this Teaching Hospital from January 1, 2000 to December 31, 2001. METHODS: Design: retrospective cohort. Patients over one year old with clinically significant episodes of BSI which were microbiologically documented were included in the study. The Cox proportional hazards risk model was applied to identify prognostic factors related to death by bacteremia. RESULTS: A total of 295 episodes of BSI were detected. The most common pathogen was S. aureus: 118 (40.0%, with 55.9% of MRSA. Mortality associated with bacteremia was 34.5%. Independent predictors of mortality were: inadequate initial therapy (HR adjusted 2.05 IC95%: 1.25-3.36 and severity of the clinical manifestations (HR adjusted 5
Andersen, Christian Østergaard; Leib, S.L.; Rowland, Ian J;
-specific pneumococcal antibodies (n=14), and III. uninfected controls (n=6). RESULTS: Pneumococcal meningitis resulted in a significantly higher apoptosis score 0.22 (0.18-0.35) compared to uninfected controls (0.02 (0.00-0.02), Mann Whitney test, P=0.0003). Also, meningitis with an attenuation of bacteremia...... by antibody treatment resulted in significantly reduced apoptosis (0.08 (0.02-0.20), P=0.01) as compared to meningitis. CONCLUSIONS: Our results demonstrate that bacteremia accompanying meningitis plays an important role in the development of hippocampal injury in pneumococcal meningitis....
Barg, N L; Supena, R B; Fekety, R
A patient with methicillin-resistant Staphylococcus aureus bacteremia received vancomycin (MIC = 0.8 microgram/ml, MBC = 15 micrograms/ml) and heparin simultaneously through the same intravenous line to treat a septic deep venous thrombosis. Bacteremia persisted for 7 days. Bacteremia terminated when the simultaneous infusion of heparin and vancomycin through the same line was stopped. This suggested that an interaction between vancomycin and heparin may have occurred, which resulted in a reduction in vancomycin activity. To test for such an interaction, mixtures of heparin and vancomycin in various concentrations were made and tested for antimicrobial activity against the organisms in the patient. A precipitate formed at the concentrations achieved in the intravenous lines, and when the vancomycin concentrations were measured by bioassay, a 50 to 60% reduction in activity was noted. In contrast, when these solutions were prepared and mixed at microgram concentrations, a precipitate was no longer observed, and antimicrobial activity was not reduced. Heparin appeared to interact unfavorably with vancomycin at the concentrations in the intravenous lines when these drugs were administered simultaneously to patients. This may be the cause of poor therapeutic responses to vancomycin in some patients, especially those infected with tolerant organisms.
Xu, Chun; Boks, Niels P; de Vries, Jacob; Kaper, Harm; Norde, Willem; Busscher, Hendrik; van der Mei, Henderina
Adhesion and residence-time-dependent desorption of two Staphylococcus aureus strains with and without fibronectin (Fn) binding proteins (FnBPs) on Fn-coated glass were compared under flow conditions. To obtain a better understanding of the role of Fn-FnBP binding, the adsorption enthalpies of Fn wi
Xu, C.P.; Boks, N.P.; Vries, de J.; Kaper, H.J.; Norde, W.; Busscher, H.J.; Mei, van der H.C.
Adhesion and residence-time-dependent desorption of two Staphylococcus aureus strains with and without fibronectin (Fn) binding proteins (FnBPs) on Fn-coated glass were compared under flow conditions. To obtain a better understanding of the role of Fn-FnBP binding, the adsorption enthalpies of Fn wi
Full Text Available Staphylococcus aureus causes a wide spectrum of infections in humans, ranging from superficial cutaneous infections, infections in the circum-oral region, to life-threatening bacteremia. It was recently demonstrated that Gram-positive organisms such as S. aureus liberate membrane-derived vesicles (MVs, which analogously to outer membrane vesicles (OMVs of Gram-negative bacteria can play a role in delivering virulence factors to host cells. In the present study we have shown that cholesterol-dependent fusion of S. aureus MVs with the plasma membrane represents a route for delivery of a key virulence factor, α-toxin (α-hemolysin; Hla to human cells. Most S. aureus strains produce this 33-kDa pore-forming protein, which can lyse a wide range of human cells, and induce apoptosis in T-lymphocytes. Our results revealed a tight association of biologically active α-toxin with membrane-derived vesicles isolated from S. aureus strain 8325-4. Concomitantly, α-toxin contributed to HeLa cell cytotoxicity of MVs, and was the main vesicle-associated protein responsible for erythrocyte lysis. In contrast, MVs obtained from an isogenic hla mutant were significantly attenuated with regards to both causing lysis of erythrocytes and death of HeLa cells. This is to our knowledge the first recognition of an S. aureus MV-associated factor contributing to host cell cytotoxicity.
van Belkum, Alex; Emonts, Marieke; Wertheim, Heiman; Bartels, Hans; Cole, Alexander; Lemmens-den Toom, Nicole; Snijders, Susan Susan; Verbrugh, Henri; van Leeuwen, Willem
Slaphylococcus aureus colonization of the human nares predisposes to sometimes severe auto-infection. To investigate whether genetic polymorphism affects the S. aureus carriage status, sequence variation in alpha-defensin and beta-defensin, and mannose-binding lectin (MBL) genes were determined for
Full Text Available We have characterized a novel pleiotropic role for CymR, the master regulator of cysteine metabolism. We show here that CymR plays an important role both in stress response and virulence of Staphylococcus aureus. Genes involved in detoxification processes, including oxidative stress response and metal ion homeostasis, were differentially expressed in a DeltacymR mutant. Deletion of cymR resulted in increased sensitivity to hydrogen peroxide-, disulfide-, tellurite- and copper-induced stresses. Estimation of metabolite pools suggests that this heightened sensitivity could be the result of profound metabolic changes in the DeltacymR mutant, with an increase in the intracellular cysteine pool and hydrogen sulfide formation. Since resistance to oxidative stress within the host organism is important for pathogen survival, we investigated the role of CymR during the infectious process. Our results indicate that the deletion of cymR promotes survival of S. aureus inside macrophages, whereas virulence of the DeltacymR mutant is highly impaired in mice. These data indicate that CymR plays a major role in virulence and adaptation of S. aureus for survival within the host.
Staphylococcus aureus is a dangerous pathogen that causes a variety of severe diseases. The virulence of S. aureus is defined by a large repertoire of virulence factors, among which secreted toxins play a preeminent role. Many S. aureus toxins damage biological membranes, leading to cell death. In particular, S. aureus produces potent hemolysins and leukotoxins. Among the latter, some were recently identified to lyse neutrophils after ingestion, representing an especially powerful weapon against bacterial elimination by innate host defense. Furthermore, S. aureus secretes many factors that inhibit the complement cascade or prevent recognition by host defenses. Several further toxins add to this multi-faceted program of S. aureus to evade elimination in the host. This review will give an overview over S. aureus toxins focusing on recent advances in our understanding of how leukotoxins work in receptor-mediated or receptor-independent fashions.
Binh An Diep
Full Text Available Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA strains typically carry genes encoding Panton-Valentine leukocidin (PVL. We used wild-type parental and isogenic PVL-deletion (Delta pvl strains of USA300 (LAC and SF8300 and USA400 (MW2 to test whether PVL alters global gene regulatory networks and contributes to pathogenesis of bacteremia, a hallmark feature of invasive staphylococcal disease. Microarray and proteomic analyses revealed that PVL does not alter gene or protein expression, thereby demonstrating that any contribution of PVL to CA-MRSA pathogenesis is not mediated through interference of global gene regulatory networks. Inasmuch as a direct role for PVL in CA-MRSA pathogenesis remains to be determined, we developed a rabbit bacteremia model of CA-MRSA infection to evaluate the effects of PVL. Following experimental infection of rabbits, an animal species whose granulocytes are more sensitive to the effects of PVL compared with the mouse, we found a contribution of PVL to pathogenesis over the time course of bacteremia. At 24 and 48 hours post infection, PVL appears to play a modest, but measurable role in pathogenesis during the early stages of bacteremic seeding of the kidney, the target organ from which bacteria were not cleared. However, the early survival advantage of this USA300 strain conferred by PVL was lost by 72 hours post infection. These data are consistent with the clinical presentation of rapid-onset, fulminant infection that has been associated with PVL-positive CA-MRSA strains. Taken together, our data indicate a modest and transient positive effect of PVL in the acute phase of bacteremia, thereby providing evidence that PVL contributes to CA-MRSA pathogenesis.
Maja Verena Nielsen
Full Text Available The objective of the study was to describe systemic bacterial infections occurring in acutely ill and hospitalized children in a rural region in Ghana, regarding frequency, incidence, antimicrobial susceptibility patterns and associations with anthropometrical data.Blood cultures were performed in all children below the age of five years, who were admitted to Agogo Presbyterian Hospital (APH, Asante Region, Ghana, between September 2007 and July 2009. Medical history and anthropometrical data were assessed using a standardized questionnaire at admission. Incidences were calculated after considering the coverage population adjusted for village-dependent health-seeking behavior.Among 1,196 hospitalized children, 19.9% (n = 238 were blood culture positive. The four most frequent isolated pathogens were nontyphoidal salmonellae (NTS (53.3%; n = 129, Staphylococcus aureus (13.2%; n = 32, Streptococcus pneumoniae (9.1%; n = 22 and Salmonella ser. Typhi (7.0%; n = 17. Yearly cumulative incidence of bacteremia was 46.6 cases/1,000 (CI 40.9-52.2. Yearly cumulative incidences per 1,000 of the four most frequent isolates were 25.2 (CI 21.1-29.4 for NTS, 6.3 (CI 4.1-8.4 for S. aureus, 4.3 (CI 2.5-6.1 for S. pneumoniae and 3.3 (CI 1.8-4.9 for Salmonella ser. Typhi. Wasting was positively associated with bacteremia and systemic NTS bloodstream infection. Children older than three months had more often NTS bacteremia than younger children. Ninety-eight percent of NTS and 100% of Salmonella ser. Typhi isolates were susceptible to ciprofloxacin, whereas both tested 100% susceptible to ceftriaxone. Seventy-seven percent of NTS and 65% of Salmonella ser. Typhi isolates were multi-drug resistant (MDR. Systemic bacterial infections in nearly 20% of hospitalized children underline the need for microbiological diagnostics, to guide targeted antimicrobial treatment and prevention of bacteremia. If microbiological diagnostics are lacking, calculated antimicrobial
Full Text Available Renal involvement has been well documented in patients with hepatosplenic schistosomiasis and in patients with prolonged salmonella bacteremia (PSB. Whether there is a specific renal lesion related to PSB or the chronic bacterial infection aggravates a pre-existing schistosomal glomerulopathy has been a matter of controversy. To analyze the clinical manifestations and histopathological findings of the renal involvement, 8 patients with hepatosplenic schistosomiasis and PSB (group I were compared with 8 patients with schistosomal glomerulopathy (group II matched by sex and glomerular disease. The mean age in group I was 17.7 years. All patients presented with hematuria, in 4 cases associated with non-nephrotic proteinuria. In group II the mean age was 23 years; nephrotic syndrome was the clinical presentation in 7 of the 8 patients in the group. All patients in group I experienced remission of the clinical and laboratory abnormalities as the salmonella infection was cured; in group II the patients had persistent, steroid-resistant, nephrotic syndrome. On histological examination, no difference was noted between the two groups, except for pronounced glomerular hypercellularity and interstitial mononuclear cell infiltration in group I. These observations strongly suggest that PSB exacerbates a pre-existing sub-clinical schistosomal glomerulopathy by the addition of active lesions directly related to the prolonged bacteremiaEnvolvimento renal tern sido documentado em pacientes com o diagnóstico de salmonelose septicêmica prolongada (SSP. Entretanto, ainda é controversa a existência de uma glomerulopatia especificamente relacionada a SSP ou se a infecção bacteriana prolongada agrava a glomerulopatia esquistossomótica pré-existente. Com o objetivo de analisar as manifestações clínicas e histológicas do envolvimento renal, 8 pacientes com o diagnostico de SSP foram estudados e comparados com 8 pacientes portadores de glomerulopatia
Wu, Chi-Jung; Chen, Po-Lin; Tang, Hung-Jen; Chen, Hung-Mo; Tseng, Fan-Chen; Shih, Hsin-I; Hung, Yuan-Pin; Chung, Chih-Huan; Ko, Wen-Chien
The aim of the investigation was to describe the incidence of Aeromonas bacteremia in a city with a population of about 1.87 million inhabitants, located in southern Taiwan, between 2008 and 2010. Such data were compared with the incidences of Vibrio and Salmonella bacteremia in the same period and the incidence of Aeromonas bacteremia in other countries in the literature. The data revealed the average annual incidences of bacteremia due to Aeromonas, Vibrio, and Salmonella species were 76, 38, and 103 cases/million inhabitants, respectively. The incidence of Aeromonas bacteremia was higher than those in Western countries.
Riu, Marta; Chiarello, Pietro; Terradas, Roser; Sala, Maria; Garcia-Alzorriz, Enric; Castells, Xavier; Grau, Santiago; Cots, Francesc
Aim To calculate the incremental cost of nosocomial bacteremia caused by the most common organisms, classified by their antimicrobial susceptibility. Methods We selected patients who developed nosocomial bacteremia caused by Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, or Pseudomonas aeruginosa. These microorganisms were analyzed because of their high prevalence and they frequently present multidrug resistance. A control group consisted of patients classified within the same all-patient refined-diagnosis related group without bacteremia. Our hospital has an established cost accounting system (full-costing) that uses activity-based criteria to analyze cost distribution. A logistic regression model was fitted to estimate the probability of developing bacteremia for each admission (propensity score) and was used for propensity score matching adjustment. Subsequently, the propensity score was included in an econometric model to adjust the incremental cost of patients who developed bacteremia, as well as differences in this cost, depending on whether the microorganism was multidrug-resistant or multidrug-sensitive. Results A total of 571 admissions with bacteremia matched the inclusion criteria and 82,022 were included in the control group. The mean cost was € 25,891 for admissions with bacteremia and € 6,750 for those without bacteremia. The mean incremental cost was estimated at € 15,151 (CI, € 11,570 to € 18,733). Multidrug-resistant P. aeruginosa bacteremia had the highest mean incremental cost, € 44,709 (CI, € 34,559 to € 54,859). Antimicrobial-susceptible E. coli nosocomial bacteremia had the lowest mean incremental cost, € 10,481 (CI, € 8,752 to € 12,210). Despite their lower cost, episodes of antimicrobial-susceptible E. coli nosocomial bacteremia had a major impact due to their high frequency. Conclusions Adjustment of hospital cost according to the organism causing bacteremia and antibiotic sensitivity could improve
Subhankari Prasad Chakraborty
Full Text Available Staphylococcus aureus is the most frequently isolated pathogen causing bloodstream infections, skin and soft tissue infections and pneumonia. Lymphocyte is an important immune cell. The aim of the present paper was to test the ameliorative role of nanoconjugated vancomycin against Vancomycin-sensitive Staphylococcus aureus (VSSA and vancomycin-resistant Staphylococcus aureus (VRSA infection-induced oxidative stress in lymphocytes. VSSA and VRSA infections were developed in Swiss mice by intraperitoneal injection of 5×106 CFU/mL bacterial solutions. Nanoconjugated vancomycin was adminstrated to VSSA- and VRSA-infected mice at its effective dose for 10 days. Vancomycin was adminstrated to VSSA- and VRSA-infected mice at a similar dose, respectively, for 10 days. Vancomycin and nanoconjugated vancomycin were adminstrated to normal mice at their effective doses for 10 days. The result of this study reveals that in vivo VSSA and VRSA infection significantly increases the level of lipid peroxidation, protein oxidation, oxidized glutathione level, nitrite generation, nitrite release, and DNA damage and decreases the level of reduced glutathione, antioxidant enzyme status, and glutathione-dependent enzymes as compared to control group, which were increased or decreased significantly near to normal in nanoconjugated vancomycin-treated group. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VSSA and VRSA infection-induced oxidative stress in lymphocytes.
Hovgaard, D; Skinhøj, P; Bangsborg, Jette Marie;
171 episodes of bacteremia and candidemia in 142 patients were recorded during the period 1981-1985 in patients with hematological malignancies. Overall mortality, within 1 week of onset of bacteremia, was 20%. Increased mortality was found in patients with poor disease-prognosis (39%), with gran...
Full Text Available Despite epidemiological data linking necrotizing skin infections with the production of Panton-Valentine leukocidin (PVL, the contribution of this toxin to the virulence of S. aureus has been highly discussed as a result of inconclusive results of in vivo studies. However, the majority of these results originate from experiments using mice, an animal species which neutrophils--the major target cells for PVL--are highly insensitive to the action of this leukocidin. In contrast, the rabbit neutrophils have been shown to be as sensitive to PVL action as human cells, making the rabbit a better experimental animal to explore the PVL role. In this study we examined whether PVL contributes to S. aureus pathogenicity by means of a rabbit skin infection model. The rabbits were injected intradermally with 10(8 cfu of either a PVL positive community-associated methicillin-resistant S. aureus isolate, its isogenic PVL knockout or a PVL complemented knockout strain, and the development of skin lesions was observed. While all strains induced skin infection, the wild type strain produced larger lesions and a higher degree of skin necrosis compared to the PVL knockout strain in the first week after the infection. The PVL expression in the rabbits was indirectly confirmed by a raise in the serum titer of anti-LukS-PV antibodies observed only in the rabbits infected with PVL positive strains. These results indicate that the rabbit model is more suitable for studying the role of PVL in staphylococcal diseases than other animal models. Further, they support the epidemiological link between PVL producing S. aureus strains and necrotizing skin infections.
Gomez, B; Hernandez-Bou, S; Garcia-Garcia, J J; Mintegi, S
A blood culture (BC) is frequently requested in both patients with a suspected occult bacteremia/invasive infection as well as those with certain focal infections. Few data are available on the characteristics of patients in whom a bacteremia is identified in the Pediatric Emergency Department (PED). A prospective multicenter registry was established by the Spanish Pediatric Emergency Society. Epidemiological data, complementary test results, clinical management, and final outcome were recorded. Data from the first three years of the registry were analyzed. A true bacterial pathogen grew in 932 of 65,169 BCs collected [1.43 %; 95 % confidence interval (CI) 1.34-1.51 %], with 711 of them collected in patients without previously known bacteremia risk factors. Among them, 335 (47.1 %) were younger than 1 year old and 467 (65.7 %) had a normal Pediatric Assessment Triangle (PAT) on admission. Overall, the most frequently isolated bacterial species was Streptococcus pneumoniae (27.3 %; 47.6 % among patients with an altered PAT). The main pathogens were Escherichia coli (40.3 %) and S. agalactiae (35.7 %) among patients younger than 3 months, S. pneumoniae among patients 3-60 months old (40.0 %), and S. aureus (31.9 %) among patients over 60 months of age. Neisseria meningitidis was the leading cause of sepsis in patients older than 3 months. Eight patients died; none of them had a pneumococcal bacteremia and all had abnormal PAT findings on admission. S. pneumoniae is the main cause of bacteremia in patients without bacteremia risk factors who attended Spanish PEDs. Age and general appearance influence the frequency of each bacterial species. General appearance also influences the associated mortality.
Saddiq, Amna Ali; Mohamed, Azza Mostafa
The aim of this study was to explore the protective impact of aqueous extract of Saudi red propolis against rat lung damage induced by the pathogenic bacteria namely methicillin resistant Staphylococcus aureus (MRSA) ATCC 6538 strain. Infected rats were received a single intraperitoneal (i.p.) injection of bacterial suspension at a dose of 1 X 10(6) CFU / 100g body weight. Results showed that oral administration of an aqueous extract of propolis (50mg/100g body weight) daily for two weeks to infected rats simultaneously with bacterial infection, effectively ameliorated the alteration of oxidative stress biomarker, malondialdehyde (MDA), as well as the antioxidant markers, glutathione peroxidase (GPx) and superoxide dismutase (SOD), in lungs of infected rats compared with infected untreated ones. Also, the used propolis extract successfully modulated the alterations in proinflammatory mediators, tumor necrosis factor-α (TNF- α) and vascular endothelial growth factor (VEGF) in serum. In addition, the propolis extract successfully modulated the oxidative DNA damage and the apoptosis biomarker, caspase 3, in lungs of S aureus infected rats compared with infected untreated animals. The biochemical results were supported by histo-pathological observation of lung tissues. In conclusion, the beneficial prophylactic role of the aqueous extract of Saudi red propolis against lung damage induced by methicillin resistant S aureus may be related to the antioxidant, anti-inflammatory, immunomodulatory and antiapoptosis of its active constituents.
Wang, Yanan; Hu, Mo; Liu, Qian; Qin, Juanxiu; Dai, Yingxin; He, Lei; Li, Tianming; Zheng, Bing; Zhou, Fan; Yu, Kaiwen; Fang, Jingyuan; Liu, Xiaoyun; Otto, Michael; Li, Min
Novel Staphylococcus aureus clones continue to emerge that cause infections in otherwise healthy people. One example is the sequence type (ST) 398 lineage, which we show here is increasing in importance as a significant cause of community-associated (CA) human infections in China. We have a profound lack of understanding about what determines the considerable virulence potential of such newly emerging clones. Information about the contribution to virulence of the more recently discovered ESAT-6 secretion system (ESS) has remained particularly scarce. The Chinese ST398 isolates exhibited significantly increased expression of ESS genes as compared to predominant hospital-associated clones, which we found is likely due to increased expression of the accessory gene regulator (Agr) system and control of ESS by Agr. Importantly, deletion of essB in ST398 resulted in significantly reduced resistance to neutrophil killing and decreased virulence in murine skin and blood infection models. Our results demonstrate a key function of ESS in promoting virulence and mechanisms of resistance to innate host defense in an important emerging CA-S. aureus lineage. They suggest that ESS has a so far underestimated role in promoting aggressive virulence and epidemiological success of S. aureus.
Role of acute graft-versus-host disease in the risk of bacteremia and invasive fungal disease after allogeneic hemopoietic stem cell transplantation in children. Results from a single-center observational study.
Castagnola, Elio; Bagnasco, Francesca; Bandettini, Roberto; Caviglia, Ilaria; Morreale, Giuseppe; Lanino, Edoardo; Giardino, Stefano; Moroni, Cristina; Haupt, Riccardo; Faraci, Maura
Data on epidemiology of severe infectious complications, ie, bacteremia or invasive fungal disease (IFD), in children with acute graft-versus-host disease (aGVHD) after allogeneic hemopoietic stem cell transplantation (HSCT) are scarce. In a retrospective, single-center study, we analyzed the risk (hazard ratio [HR]) and the rate (episodes/1000 patients days at risk) of bacteremias and IFD in children receiving allogeneic HSCT, according to the type of donor (matched related [MRD] or alternative [AD]) and presence and grade of aGVHD. From 2000 to 2009, 198 children receiving 217 allogeneic HSCT developed 134 severe infectious episodes (103 bacteremias and 31 IFD). The type of donor (AD versus MRD) was the most important risk factor for the severe infections (P = .0052). In separate multivariable analysis for bacteremia and IFD, children receiving an AD HSCT had increased HR and rate of bacteremia compared with those receiving a MRD transplantation (P = .0171 and P = .0001, respectively), whereas the HR and the rate of IFD were significantly influenced by the grade of aGVHD (P = .0002 and P design management strategies of infections in pediatric allogeneic HSCT.
Cucarella, Carme; Tormo, M Angeles; Ubeda, Carles; Trotonda, M Pilar; Monzón, Marta; Peris, Critòfol; Amorena, Beatriz; Lasa, Iñigo; Penadés, José R
Staphylococcus aureus is a common cause of intramammary infections, which frequently become chronic, associated with the ability of the bacteria to produce biofilm. Here, we report a relationship between the ability to produce chronic bovine mastitis and biofilm formation. We have classified bovine mastitis S. aureus isolates into three groups based on the presence of particular genetic elements required for biofilm formation: group 1 (ica(+) bap(+)), group 2 (ica(+), bap negative), and group 3 (ica negative, bap negative). Overall, animals naturally infected with group 1 and 2 isolates had a lower milk somatic cell count than those infected with isolates of group 3. In addition, Bap-positive isolates were significantly more able to colonize and persist in the bovine mammary gland in vivo and were less susceptible to antibiotic treatments when forming biofilms in vitro. Analysis of the structural bap gene revealed the existence of alternate forms of expression of the Bap protein in S. aureus isolates obtained under field conditions throughout the animal's life. The presence of anti-Bap antibodies in serum samples taken from animals with confirmed S. aureus infections indicated the production of Bap during infection. Furthermore, disruption of the ica operon in a bap-positive strain had no effect on in vitro biofilm formation, a finding which strongly suggested that Bap could compensate for the deficiency of the PIA/PNAG product (a biofilm matrix polysaccharide). Altogether, these results demonstrate that, in the bovine intramammary gland, the presence of Bap may facilitate a biofilm formation connected with the persistence of S. aureus.
Burts, Monica L.; DeDent, Andrea C.; Missiakas, Dominique M.
Staphylococcus aureus encodes the specialized secretion system Ess (ESAT-6 secretion system). The ess locus is a cluster of eight genes (esxAB, essABC, esaABC) of which esxA and esxB display homology to secreted ESAT-6 proteins of Mycobacterium tuberculosis. EsxA and EsxB require EssA, EssB and EssC for transport across the staphylococcal envelope. Herein, we examine the role of EsaB and EsaC and show that EsaB is a negative regulator of EsaC. Further, EsaC production is repressed when staphy...
Hagiya, Hideharu; Ogawa, Hiroko; Takahashi, Yusuke; Kimura, Kosuke; Hasegawa, Kan; Otsuka, Fumio
We herein present a rare case of Actinomyces turicensis bacteremia that was caused by pyometra. The patient was successfully treated with transvaginal drainage and antibiotic therapy. A literature review in MEDLINE showed that there have been only 8 previously reported cases of A. turicensis bacteremia. This infection frequently occurs in patients with visceral abscesses, and blood culture examinations usually reveal a polymicrobial pattern. However, the prognosis of such patients has been reported to generally be benign. Due to difficulties in performing bacterial identification and the wide-spectrum clinical pictures associated with this bacteremia, no comprehensive understanding of the clinical features of each Actinomyces species has yet been established.
... Fundamentals Heart and Blood Vessel Disorders Hormonal and Metabolic Disorders Immune Disorders Infections Injuries and Poisoning Kidney and ... Fundamentals Heart and Blood Vessel Disorders Hormonal and Metabolic Disorders Immune Disorders Infections Injuries and Poisoning Kidney and ...
Jin, Tao; Lu, Yong; He, Qing Xiao; Wang, Hai; Li, Bing Fu; Zhu, Liang Yue; Xu, Qing Yong
Osteomyelitis is a debilitating infectious disease of the bone which is predominantly caused by Staphylococcus aureus (S. aureus). MicroRNAs (miRNAs) have been shown to play a regulatory role in osteogenesis. In the present study, the expression levels of miRNAs proposed to potentially play a regulatory role in bone formation or differentiation (miR-24, miR-29b, miR-200a, miR-208, miR-322) were analyzed in the whole blood of patients with bacterial osteomyelitis or healthy controls, and in MC3T3-E1 cells infected with S. aureus by qRT-PCR. The expression of miR-24 was significantly down-regulated in osteomyelitis patients and S. aureus-infected MC3T3-E1 cells compared with the healthy controls or untreated control cells. Moreover, our results showed that S. aureus inhibited MC3T3-E1 cell proliferation, induced osteoblast apoptosis and prohibited bone formation and mineralization. We found that overexpression of miR-24 could reduce the effects of S. aureus, while inhibition of miR-24 intensified the effects. We also demonstrated that miR-24 suppressed the expression of chitinase 3-like 1 (CHI3L1) mRNA, thought to mediate multiple signaling pathways, by directly binding to the 3'-untranslated region.
Vinés, Enrique D; Speziali, Craig D; Heinrichs, David E
The features that govern the interaction of ligand binding proteins with membrane permeases of cognate ABC transporters are largely unknown. Using sequence alignments and structural modeling based on the structure of the Escherichia coli BtuCD vitamin B12 transporter, we identified six conserved basic residues in the permease, comprised of FhuB and FhuG proteins, in the ferrichrome transporter of Staphylococcus aureus. Using alanine-scanning mutagenesis we demonstrate that two of these residues, FhuB Arg-71 and FhuG Arg-61, play a more dominant role in transporter function than FhuB Arg-74 and Arg-311, and FhuG Arg-64 and Lys-306. Moreover, we show that at positions 71 and 61 in FhuB and FhuG, respectively, arginine cannot be substituted for lysine without loss of transporter function. Previously, our laboratory demonstrated the importance of conserved acidic residues in the ferrichrome binding protein, FhuD2. Taken together, these results support the hypothesis that Glu-Arg salt bridges are critical for the interaction of the ligand binding protein with the transmembrane domains FhuB and FhuG. This hypothesis was further studied by "charge swapping" experiments whereby we constructed a S. aureus strain expressing FhuD2 with conserved residues Glu-97 and Glu-231 replaced by Arg and FhuB and FhuG with conserved basic residues Arg-71 and Arg-61, respectively, replaced by Glu. A strain containing this combination of substitutions restored partial function to the ferrichrome transporter. The results provide a direct demonstration of the functional importance of conserved basic residues on the extracellular surface of the ferrichrome permease in the Gram-positive bacterium S. aureus.
cytoprotection of infected cells leading to apoptosis. Increased MCL1 expression in infected cells was associated with enhanced NFκB activation and subsequent IL-6 secretion, since the inhibition of both NFκB and IL-6 signalling pathways abrogated Mcl-1 induction and cytoprotection. Finally, we confirmed our observation in vivo in murine model of septic arthritis showing the association between the severity of arthritis and Mcl-1 expression. Therefore, we propose that S. aureus is hijacking the Mcl-1-dependent inhibition of apoptosis to prevent the elimination of infected host cells, thus allowing the intracellular persistence of the pathogen, its dissemination by infected macrophages, and the progression of staphylococci diseases.
Purves, Joanne; Cockayne, Alan; Moody, Peter C E; Morrissey, Julie A
The Gram-positive bacterium Staphylococcus aureus contains two glyceraldehyde-3-phosphate dehydrogenase (GAPDH) homologues known as GapA and GapB. GapA has been characterized as a functional GAPDH protein, but currently there is no biological evidence for the role of GapB in metabolism in S. aureus. In this study we show through a number of complementary methods that S. aureus GapA is essential for glycolysis while GapB is essential in gluconeogenesis. These proteins are reciprocally regulated in response to glucose concentrations, and both are influenced by the glycolysis regulator protein GapR, which is the first demonstration of the role of this regulator in S. aureus and the first indication that GapR homologues control genes other than those within the glycolytic operon. Furthermore, we show that both GapA and GapB are important in the pathogenesis of S. aureus in a Galleria mellonella model of infection, showing for the first time in any bacteria that both glycolysis and gluconeogenesis have important roles in virulence.
Tao Wang; Yun-Liang Cui; Zhao-Fen Lin; De-Chang Chen
Background: Both procalcitonin (PCT) and plasma endotoxin levels cannot be solely used for a definite diagnosis ofbacteremia or sepsis, and there has been few study comparing the values of the two biomarkers for the diagnosis of bacteremia.The aim of this study was to identify bacteria causing bacteremia and evaluate the role of the two biomarkers in the diagnosis ofbacteremia in Intensive Care Unit (ICU).Methods: The medical records of 420 patients in ICU were retrospectively reviewed.Patients (n =241) who met the inclusion criteria were subjected to blood culture (BC) for the analysis of the endotoxin or PCT levels.The exclusion criteria included the presence of infection with human immunodeficiency virus and/or AIDS, neutropenia without sepsis, pregnancy, treatment with immunosuppressive therapies, or blood diseases such as hematological tumors.Patients' BC episodes were divided into BC negative, Gram-negative (GN) bacteria, Gram-positive bacteria, and fungi groups.The PCT and plasma endotoxin levels were compared in the different groups.Results: A total of 241 patients with 505 episodes of BC were analyzed.The GN bacteria group showed higher levels of PCT and endotoxin than the BC negative, Gram-positive bacteria, and fungi groups.GN bacteremia was more prevalent than Gram-positive bacteremia.The GN bacteremia caused by non-Enterobacteriaceae infection presented higher endotoxin level than that by Enterobacteriaceae, but no significant difference in PCT levels was observed between the two groups.The plasma endotoxin significantly differed among different groups and was bacterial species dependent.Conclusions: Plasma endotoxin was more related to GN than to Gram-positive bacteremia, and that endotoxin level was species dependent, but PCT level remained relatively more stable within the GN bacteria caused bacteremia.Both GN and positive bacteria caused bacteremia in the ICU patients in different regions of China.And PCT is a more valuable biomarker than endotoxin
Zurek, Oliwia W; Nygaard, Tyler K; Watkins, Robert L; Pallister, Kyler B; Torres, Victor J; Horswill, Alexander R; Voyich, Jovanka M
The ability of Staphylococcus aureus to infect tissues is dependent on precise control of virulence through gene-regulatory systems. While the SaeR/S two-component system has been shown to be a major regulator of S. aureus virulence, the influence of the host environment on SaeR/S-regulated genes (saeR/S targets) remains incompletely defined. Using QuantiGene 2.0 transcriptional assays, we examined expression of genes with the SaeR binding site in USA300 exposed to human and mouse neutrophils and host-derived peptides and during subcutaneous skin infection. We found that only some of the saeR/S targets, as opposed to the entire SaeR/S virulon, were activated within 5 and 10 min of interacting with human neutrophils as well as α-defensin. Furthermore, mouse neutrophils promoted transcription of saeR/S targets despite lacking α-defensin, and the murine skin environment elicited a distinctive expression profile of saeR/S targets. These findings indicate that saeR/S-mediated transcription is unique to and dependent on specific host stimuli. By using isogenic USA300ΔsaeR/S and USA300Δagr knockout strains, we also determined that SaeR/S is the major regulator of virulence factors, while Agr, a quorum-sensing two-component system, has moderate influence on transcription of the saeR/S targets under the tested physiological conditions.
SHI Yan; DU Bin; XU Ying-chun; RUI Xi; DU Wei; WANG Yao
Background Rapid detection of bacteremia is important for critically ill patients.Procalcitonin (PCT) has emerged as a marker of sepsis,but its characterization for predicting bacteremia is still unclear.This study aimed to investigate the role of change of PCT within 6 to 12 hours after new fever in predicting bacteremia.Methods An observational study was conducted in the ICU of our hospital from January 2009 to March 2010.Adult patients with new fever were included and grouped as bacteremia and non bacteremia group.Serum PCT concentration was measured at admission and within 6 to12 hours after new fever (designated PCT0 and PCT1).Other results of laboratory tests and therapeutic interventions were recorded.Multivariate Logistic regression analysis was used to identify the risk factors of bacteremia.The area under the ROC curve (AUC) was constructed to evaluate the discriminative power of variables to predict bacteremia.Results Totally 106 patients were enrolled,60 of whom had bacteremia and 46 did not have bacteremia,.The acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and sequential organ failure assessment (SOFA) scores were 13.1±7.8 and 5.0±2.2 at admission,respectively.There was no significant difference in PCT0 between the bacteremia group and nonbacteremia group； 1.27μg/L (range,0.10-33.3) vs.0.98μg/L (range,0.08-25.7),(P=-0.157).However,the PCT1 and the rate of change of PCT were significantly higher in bacteremia group； PCT1 was 6.73μg/L (1.13-120.10)vs.1.17μg/L (0.10-12.10) (P=0.001),and the rate of change was 5.62 times (1.05-120.6) vs.0.07 times (-0.03-0.18)(P＜0.001).The area under the ROC curve (AUC； 95％ confidence interval) of the rate of change of PCT was better for predicting bacteremia than that of PCT1； 0.864 (range,0.801-0.927) vs.0.715 (range,0.628-0.801),(P＜0.05).The AUCs of PCT0 and other parameters (such as WBC count,granulocyte percentage and temperature) were not significantly different (all P＞0
Saadi, A T; Blackwell, C C; Raza, M W; James, V S; Stewart, J; Elton, R A; Weir, D M
Toxigenic strains of Staphylococcus aureus have been suggested to play a role in sudden infant death syndrome (SIDS). In this study we examined two factors that might enhance binding of toxigenic staphylococci to epithelial cells of infants in the age range in which cot deaths are prevalent: expression of the Lewis(a) antigen and infection with respiratory syncytial virus (RSV). By flow cytometry we demonstrated that binding of three toxigenic strains of S. aureus to cells from nonsecretors was significantly greater than to cells of secretors. Pre-treatment of epithelial cells with monoclonal anti-Lewis(a) or anti-type-1 precursor significantly reduced bacterial binding (P < 0.01); however, attachment of the bacteria correlated only with the amount of Lewis(a) antigen detected on the cells (P < 0.01). HEp-2 cells infected with RSV bound significantly more bacteria than uninfected cells. These findings are discussed in context of factors previously associated with SIDS (mother's smoking, bottle feeding and the prone sleeping position) and a hypothesis proposed to explain some cases of SIDS.
Full Text Available Abstract Background Ertapenem is a once-a-day carbapenem and has excellent activity against many gram-positive and gram-negative aerobic, facultative, and anaerobic bacteria. The susceptibility of isolates of community-acquired bacteremia to ertapenem has not been reported yet. The present study assesses the in vitro activity of ertapenem against aerobic and facultative bacterial pathogens isolated from patients with community-acquired bacteremia by determining and comparing the MICs of cefepime, cefoxitin, ceftazidime, ceftriaxone, ertapenem, piperacillin, piperacillin-tazobactam, ciprofloxacin, amikacin and gentamicin. The prevalence of extended broad spectrum β-lactamases (ESBL producing strains of community-acquired bacteremia and their susceptibility to these antibiotics are investigated. Methods Aerobic and facultative bacteria isolated from blood obtained from hospitalized patients with community-acquired bacteremia within 48 hours of admission between August 1, 2004 and September 30, 2004 in Chang Gung Memorial Hospital at Keelung, Taiwan, were identified using standard procedures. Antimicrobial susceptibility was evaluated by Etest according to the standard guidelines provided by the manufacturer and document M100-S16 Performance Standards of the Clinical Laboratory of Standard Institute. Antimicrobial agents including cefepime, cefoxitin, ceftazidime, ceftriaxone, ertapenem, piperacillin, piperacillin-tazobactam, ciprofloxacin, amikacin and gentamicin were used against the bacterial isolates to test their MICs as determined by Etest. For Staphylococcus aureus isolates, MICs of oxacillin were also tested by Etest to differentiate oxacillin-sensitive and oxacillin-resistant S. aureus. Results Ertapenem was highly active in vitro against many aerobic and facultative bacterial pathogens commonly recovered from patients with community-acquired bacteremia (128/159, 80.5 %. Ertapenem had more potent activity than ceftriaxone, piperacillin
Full Text Available Objective: To investigate microorganisms causing bacteremia in Jordanian children and to assess their sensitivity to various groups of antimicrobials."nMethods: A retrospective study was conducted on positive blood cultures taken from 378 children aged below 15 year, who sought medical attention at Princess Rahmah Hospital between January and December/2008."nResults: Out of 4475 tested blood samples, 378 isolates were recovered from blood cultures. The male to female isolate ratio was (1.26:1.0. The most frequent pathogen found was Staphylococcus aureus (86.2%, followed by Klebsiella spp. (9%, Escherichia coli (1.9%, Streptococcus spp. (1.9%, Pseudomonas spp. (0.8%, and Acinetobacter sp. was found in only one culture (0.3%. The susceptibility rate of S. aureus was recorded the highest (99.6% for vancomycin, and the lowest susceptibility rate (3.2% was recorded for aztreonam."nConclusions: Staphylococcus aureus was the main isolate in bacteremic children, with all isolates demonstrating susceptibility to vancomycin. Overall, aztreonam resistance was near 97%, and this rate was not affected by sex and blood isolate type. This information should be considered when empirical therapy is recommended or prescribed for children with bacteremia.
Hansen, Sanne Grønvall Kjær; Skov, Marianne N; Justesen, Ulrik S
We report two cases of bacteremia with the anaerobic bacterium Ruminococcus gnavus. In both cases, the bacteremia was associated with diverticular disease. Preliminary conventional identification suggested peptostreptococci, and matrix-assisted laser desorption ionization-time of flight mass spec...
Mirani, Zulfiqar Ali; Aziz, Mubashir; Khan, Seema Ismat
The present study was conducted to investigate the significance of small colony variants (SCVs) in biofilm life cycle of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). All of these MRSA and MSSA isolates were recovered from different food commodities. Molecular typing showed that 21 MRSA isolates carry SCCmecA type IV and belong to agr type II. Out of 15 MSSA isolates, 7 were found to carry agr type II, 5 agr type I and 2 agr type III. All of the MRSA isolates studied adopted biofilm mode of growth after exposure to sublethal doses of oxacillin. MSSA isolates, on the other hand, were biofilm producers by nature, that is, without exposure to any stress. The biomass of the biofilm reaches its maximum thickness after 48 h of incubation at 35 °C. It was noticed that biofilm population consists of wild type and SCVs. Moreover, the number of SCVs increases with the age of biofilm. The SCVs of MRSA were unable to readopt biofilm mode of growth independently, irrespective of the presence or absence of oxacillin. The SCVs of MSSA, on the other hand, quickly revert to normal life just after a single subculture and show biofilm formation without any stress. Molecular studies showed a parallel reduction in the expression of the genes icaA, sigβ and sarA, and also in the extracellular matrix production in SCVs of MRSA. This might be due to oxacillin as it seems to be a stress factor responsible for induction of biofilm formation in MRSA isolates. Contrary to the wild type, SCVs are metabolically inactive and do not respond to oxacillin, which is only active against the growing cells. Therefore, stress-responsive genes, that is, sigβ and sarA, are not induced. Conversely, MSSA isolates are natural biofilm producers without induction through any known factors.
Nielsen, Stig Lønberg; Lassen, Annmarie Touborg; Gradel, Kim Oren;
OBJECTIVES: Little is known about long-term outcomes following bacteremia. We investigated long-term mortality and causes of death among bacteremia patients compared with population controls. METHODS: Population-based cohort study of bacteremia patients and population controls matched on sex, yea...
Hung, C C; Chang, S C; Chen, Y C; Hsieh, W C; Luh, K T
Listeria monocytogenes has been recognized as an important pathogen in immunocompromised patients, but it has been rarely reported in Taiwan. We reviewed 13 cases of L. monocytogenes bacteremia at National Taiwan University Hospital over a 12-year period. All of the patients had underlying diseases. Fever was the most common presenting symptom, and neurologic signs were found in 6 patients. Most of the patients received penicillin G, ampicillin or piperacillin with an aminoglycoside. Corticosteroids were used in 9 of 13 patients. The overall mortality directly due to L. monocytogenes bacteremia was 31%. However, patients treated with cephalosporins or oxacillin had higher mortality than those treated with penicillin G, ampicillin or piperacillin (p = 0.05). Given the increasing number of immunosuppressed patients in Taiwan, it is likely that more cases will be encountered. Physicians in Taiwan should be aware of L. monocytogenes bacteremia and its treatment.
Chu, Ming; Zhang, Ming-Bo; Liu, Yan-Chen; Kang, Jia-Rui; Chu, Zheng-Yun; Yin, Kai-Lin; Ding, Ling-Yu; Ding, Ran; Xiao, Rong-Xin; Yin, Yi-Nan; Liu, Xiao-Yan; Wang, Yue-Dan
Berberine is an isoquinoline alkaloid widely used in the treatment of microbial infections. Recent studies have shown that berberine can enhance the inhibitory efficacy of antibiotics against clinical multi-drug resistant isolates of methicillin-resistant Staphylococcus aureus (MRSA). However, the underlying mechanisms are poorly understood. Here, we demonstrated that sub-minimum inhibitory concentrations (MICs) of berberine exhibited no bactericidal activity against MRSA, but affected MRSA biofilm development in a dose dependent manner within the concentration ranging from 1 to 64 μg/mL. Further study indicated that berberine inhibited MRSA amyloid fibrils formation, which consist of phenol-soluble modulins (PSMs). Molecular dynamics simulation revealed that berberine could bind with the phenyl ring of Phe19 in PSMα2 through hydrophobic interaction. Collectively, berberine can inhibit MRSA biofilm formation via affecting PSMs’ aggregation into amyloid fibrils, and thereby enhance bactericidal activity of antibiotics. These findings will provide new insights into the multiple pharmacological properties of berberine in the treatment of microbial-generated amyloid involved diseases.
Ramírez-Quintero, Juan David
Full Text Available Raoultella planticola, a bacteria found in water and soil, is rarely associated to human disease, mostly bacteremia and gastrointestinal infections. It is usually related with health care procedures or affects patients with malignant biliary disease. If properly treated, this infection is usually benign, but the germ must not be disregarded as an innocent bystander because it has homology with Klebsiella spp., and therefore the potential to acquire antimicrobial resistance mechanisms like bla KPC genes. We report the case of a patient with community-aquired R. planticola bacteremia of gastrointestinal origin.
Full Text Available Abstract Background Yeast and bacteria elicit arachidonate release in macrophages, leading to the formation of leukotrienes and prostaglandins, important mediators of inflammation. Receptors recognising various microbes have been identified, but the signalling pathways are not entirely understood. Cytosolic phospholipase A2 is a major down-stream target and this enzyme is regulated by both phosphorylation and an increase in intracellular Ca2+. Potential signal components are MAP kinases, phosphatidylinositol 3-kinase and phospholipase Cγ2. The latter can undergo tyrosine phosphorylation, and Src family kinases might carry out this phosphorylation. Btk, a Tec family kinase, could also be important. Our aim was to further elucidate the role of Src family kinases and Btk. Methods Arachidonate release from murine peritoneal macrophages was measured by prior radiolabeling. Furthermore, immunoprecipitation and Western blotting were used to monitor changes in activity/phosphorylation of intermediate signal components. To determine the role of Src family kinases two different inhibitors with broad specificity (PP2 and the Src kinase inhibitor 1, SKI-1 were used as well as the Btk inhibitor LFM-A13. Results Arachidonate release initiated by either Staphylococcus aureus or yeast-derived zymosan beads was shown to depend on members of the Src kinase family as well as Btk. Src kinases were found to act upstream of Btk, phosphatidylinositol 3-kinase, phospholipase Cγ2 and the MAP kinases ERK and p38, thereby affecting all branches of the signalling investigated. In contrast, Btk was not involved in the activation of the MAP-kinases. Since the cytosolic phospholipase A2 in macrophages is regulated by both phosphorylation (via ERK and p38 and an increase in intracellular Ca2+, we propose that members of the Src kinase family are involved in both types of regulation, while the role of Btk may be restricted to the latter type. Conclusion Arachidonate release
Full Text Available Staphylococcus schleiferi subsp. schleiferi is a coagulase-negative Staphylococcus which has been described as a pathogen responsible for various nosocomial infections including bacteremia, brain abscess, and infection of intravenous pacemakers. Recently, such bacteria have been described to be found typically on skin and mucosal surfaces. It is also believed to be a part of the preaxillary human flora and more frequently found in men. It is very similar in its pathogenicity with Staphylococcus aureus group and expresses a fibronectin binding protein. Literature on this pathogen reveals that it commonly causes otitis among dogs because of its location in the auditory meatus of canines. Also, it has strong association with pyoderma in dogs. The prime concern with this organism is the antibiotic resistance and relapse even after appropriate treatment. Very rarely, if any, cases have been reported about prostatic abscess (PA with this microbe. Our patient had a history of recurrent UTIs and subsequent PA resulting in S. schleiferi bacteremia in contrast to gram negative bacteremia commonly associated with UTI. This organism was found to be resistant to methicillin, in spite of being negative for PBP2, which is a rare phenomenon and needs further studies.
Sjöström, J E; Philipson, L
Both phage ø11 and 83A, when present as prophage or when used as helper phage, induce competence for transfection and transformation to the same level in Staphylococcus aureus, strain 8325-4. Cells lysogenized with certain temperature-sensitive (ts) mutants of phage ø11 show competence at the nonpermissive temperature (41 C) without production of infectious phages. Phage ø11ts allele 31 can neither as a prophage nor as a helper phage develop competence under nonpermissive conditions. This mutant appears, therefore, to be mutated in the region of the phage genome controlling competence. The competence level for both transfection and transformation is increased by superinfecting strain 8325-4 (ø11) or 8325-4 (83A) at high multiplicities with phage ø11 with some of its mutants or with phage 83A. This superinfection enhancement appears to require protein synthesis but not deoxyribonucleic acid synthesis as judged from studies with inhibitors of macromolecular synthesis. Besides the phage particle, no extracellular or cell-bound factors so far detected can induce competence. The phage-induced product conferring competence is rapidly synthesized by strain 8325-4 (tsø11(31)) after shift to permissive conditions, but requires deoxyribonucleic acid and protein synthesis to be expressed. Recombination between the sus mutants of phage ø11 of Kretschmer and Egan and tsø11(31) indicate that competence is controlled by an early gene in the lytic cycle which may be expressed also in lysogenic cells. The phage product inducing competence appears to have a half-life of 10 to 15 min in the conditional lethal mutant at shift to nonpermissive temperature. Ultraviolet inactivation of phage ø11 infectivity occurs more rapidly than inactivation of competence induction. In fact, the number of transformants is increased at low doses of irradiation. Competence induction is, however, decreased at high does of ultraviolet irradiation.
Perrin, Monique; Bemer, Michel; Delamare, Catherine
Listeria innocua is widespread in the environment and in food. This species has to date never been described in association with human disease. We report a case of fatal bacteremia caused by L. innocua in a 62-year-old patient.
Loughran, Allister J; Atwood, Danielle N; Anthony, Allison C; Harik, Nada S; Spencer, Horace J; Beenken, Karen E; Smeltzer, Mark S
We demonstrate that the purified Staphylococcus aureus extracellular proteases aureolysin, ScpA, SspA, and SspB limit biofilm formation, with aureolysin having the greatest impact. Using protease-deficient derivatives of LAC, we confirmed that this is due to the individual proteases themselves. Purified aureolysin, and to a lesser extent ScpA and SspB, also promoted dispersal of an established biofilm. Mutation of the genes encoding these proteases also only partially restored biofilm formation in an FPR3757 sarA mutant and had little impact on restoring virulence in a murine bacteremia model. In contrast, eliminating the production of all of these proteases fully restored both biofilm formation and virulence in a sarA mutant generated in the closely related USA300 strain LAC. These results confirm an important role for multiple extracellular proteases in S. aureus pathogenesis and the importance of sarA in repressing their production. Moreover, purified aureolysin limited biofilm formation in 14 of 15 methicillin-resistant isolates and 11 of 15 methicillin-susceptible isolates, while dispersin B had little impact in UAMS-1, LAC, or 29 of 30 contemporary isolates of S. aureus. This suggests that the role of sarA and its impact on protease production is important in diverse strains of S. aureus irrespective of their methicillin resistance status.
M. Pujol (Miquel); C. Pena; R. Pallares (Roman); J. Ayats (Josefina); J. Ariza (Javier); F. Gudiol (Francesc)
textabstractIn a prospective surveillance study (February 1990–December 1991) performed at a 1000-bed teaching hospital to identify risk factors for nosocomial methicillin-resistantStaphylococcus aureus (MRSA) bacteremia, 309 patients were found to be colonized (n=103; 33 %) or infected (n=206; 67 %
Burts, Monica L; DeDent, Andrea C; Missiakas, Dominique M
Staphylococcus aureus encodes the specialized secretion system Ess (ESAT-6 secretion system). The ess locus is a cluster of eight genes (esxAB, essABC, esaABC) of which esxA and esxB display homology to secreted ESAT-6 proteins of Mycobacterium tuberculosis. EsxA and EsxB require EssA, EssB and EssC for transport across the staphylococcal envelope. Herein, we examine the role of EsaB and EsaC and show that EsaB is a negative regulator of EsaC. Further, EsaC production is repressed when staphylococci are grown in broth and increased when staphylococci replicate in serum or infected hosts. EsaB is constitutively produced and remains in the cytoplasm whereas EsaC is secreted. This secretion requires an intact Ess pathway. Mutants lacking esaB or esaC display only a small defect in acute infection, but remarkably are unable to promote persistent abscesses during animal infection. Together, the data suggest a model whereby EsaB controls the production of effector molecules that are important for host pathogen interaction. One such effector, EsaC, is a secretion substrate of the Ess pathway and implements its pathogenic function during infection.
Soares da Costa, Tatiana P; Yap, Min Y; Perugini, Matthew A; Wallace, John C; Abell, Andrew D; Wilce, Matthew C J; Polyak, Steven W; Booker, Grant W
Protein biotinylation is catalysed by biotin protein ligase (BPL). The most characterized BPL is from Escherichia coli where it functions as both a biotin ligase and a homodimeric transcriptional repressor. Here we investigated another bifunctional BPL from the clinically important Staphylococcus aureus (SaBPL). Unliganded SaBPL (apo) exists in a dimer-monomer equilibrium at low micromolar concentrations - a stark contrast to E. coli BPL (EcBPL) that is monomeric under the same conditions. EMSA and SAXS analysis demonstrated that dimeric apo SaBPL adopted a conformation that was competent to bind DNA and necessary for it to function as a transcription factor. The SaBPL dimer-monomer dissociation constant was 5.8-fold tighter when binding the inhibitor biotin acetylene, but unchanged with biotin. F123, located in the dimer interface, was critical for homodimerization. Inhibition studies together with surface plasmon resonance analyses revealed a strong correlation between inhibitor potency and slow dissociation kinetics. A 24-fold difference in Ki values for these two enzymes was explained by differences in enzyme:inhibitor dissociation rates. Substitution of F123 in SaBPL and its equivalent in EcBPL altered both inhibitor potency and dissociation. Hence, F123 in SaBPL has novel roles in both protein dimerization and ligand-binding that have not been reported in EcBPL.
Full Text Available Chest pain is a common presenting symptom with a broad differential. Life-threatening cardiac and pulmonary etiologies of chest pain should be evaluated first. However, it is critical to perform a thorough assessment for other sources of chest pain in order to limit morbidity and mortality from less common causes. We present a rare case of a previously healthy 45 year old man who presented with focal, substernal, reproducible chest pain and Staphylococcus aureus bacteremia who was later found to have primary Staphylococcus aureus sternal osteomyelitis.
Full Text Available INTRODUCTION: Recent studies have shown that apoptosis plays a critical role in the pathogenesis of sepsis. High plasma cell free DNA (cf-DNA concentrations have been shown to be associated with sepsis outcome. The origin of cf-DNA is unclear. METHODS: Total plasma cf-DNA was quantified directly in plasma and the amplifiable cf-DNA assessed using quantitative PCR in 132 patients with bacteremia caused by Staphylococcus aureus, Streptococcus pneumoniae, ß-hemolytic streptococcae or Escherichia coli. The quality of cf-DNA was analyzed with a DNA Chip assay performed on 8 survivors and 8 nonsurvivors. Values were measured on days 1-4 after positive blood culture, on day 5-17 and on recovery. RESULTS: The maximum cf-DNA values on days 1-4 (n = 132 were markedly higher in nonsurvivors compared to survivors (2.03 vs 1.26 ug/ml, p1.52 ug/ml remained an independent risk factor for case fatality in a logistic regression model. Qualitative analysis of cf-DNA showed that cf-DNA displayed a predominating low-molecular-weight cf-DNA band (150-200 bp in nonsurvivors, corresponding to the size of the apoptotic nucleosomal DNA. cf-DNA concentration showed a significant positive correlation with visually graded apoptotic band intensity (R = 0.822, p<0.001. CONCLUSIONS: Plasma cf-DNA concentration proved to be a specific independent prognostic biomarker in bacteremia. cf-DNA displayed a predominating low-molecular-weight cf-DNA band in nonsurvivors corresponding to the size of apoptotic nucleosomal DNA.
Na, Sun Hee; Kim, Chung-Jong; Kim, Moonsuk; Park, Jeong Su; Song, Kyoung-Ho; Choe, Pyoeng Gyun; Park, Wan Beom; Bang, Ji-Hwan; Kim, Eu Suk; Park, Sang Won; Park, Kyoung Un; Kim, Nam Joong; Oh, Myoung-Don; Kim, Hong Bin
Rapid identification of the microorganisms in patients with bacteremia may be useful in clinical practice. We evaluated the impact of the multiplex polymerase chain reaction (PCR) on appropriate antibiotic use for patients with gram-positive cocci cluster (GPCC) bacteremia. We divided the GPCC bacteremia cases into a pre-PCR group (2010-2011) and a post-PCR group (2012-2013). A total 664 cases were included in the pre-PCR group; and 570, in the post-PCR group. In methicillin-susceptible Staphylococcus aureus (MSSA) cases, optimal antibiotics were administered earlier in the post-PCR group (77.4h versus 42.6h, P=0.035). Although the proportions of glycopeptide exposure did not differ (54.7% versus 56.7%, P=0.799), the duration of exposure decreased (69.6h versus 30.7h, P=0.004). In methicillin-resistant S. aureus cases, the time to optimal antibiotics administration did not differ (45.4h versus 43.7h, P=0.275). Multiplex PCR test significantly improved the early initiation of optimal antibiotics in MSSA bacteremia and reduced the unnecessary glycopeptide exposure.
du Moulin, G C; Lynch, S E; Hedley-Whyte, J; Broitman, S A
A spectrophotometric Limulus amebocyte lysate assay using lysis filtration and centrifugation has been developed for the detection of gram-negative bacteria in blood. The assay is directed at detection of endotoxin in viable and nonviable bacteria present in the blood-stream and not detection of free endotoxin in plasma. The assay was evaluated in a model of peritonitis in which rats were challenged with an inoculum consisting of sterilized human feces, barium sulfate, and one of eight species of bacteria. This assay was able to detect gram-negative bacteremia due to Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Proteus mirabilis, and Klebsiella pneumoniae in the rat model when compared with sham-inoculated uninfected rats. The assay failed to detect bacteremia due to Bacteroides fragilis or Staphylococcus aureus, nor was there a significant rise in absorbance when a pellet containing sterilized feces was implanted in the rat.
Nielsen, Stig Lønberg
for an overall incidence rate of 215.7 per 100,000 person years including 99.0 for community-acquired, 50.0 for healthcare-associated and 66.7 for nosocomial bacteremia. The overall incidence rate decreased by 23.3% (95% CI, 17.8%-28.4%) from year 2000 to 2008 (3.3% per year, p... of community-acquired bacteremia (3.7% per year, p nosocomial bacteremia (4.2% per year, p... were cancer and cardiovascular diseases. Compared with population controls, bacteremia patients were at the highest risk of death from genitourinary diseases and infectious diseases within 1 year of bacteremia. Among 1-year survivors of bacteremia, the risk of death was increased for all major causes...
Foster, Timothy; McDevitt, D
textabstractA class of proteins that are associated with the cell surface of Gram-positive bacteria has been recognised. Common structural features which are implicated in the proper secretion and attachment of these proteins to the cell surface occur in the C-termini. N-terminal domains interact with the host by binding to soluble host proteins, to matrix proteins or to host cells. They probably have important roles in pathogenicity by allowing bacteria to avoid host defences and by acting a...
Chen, Chang-Hua; Wu, Shun-Sheng; Huang, Chieh-Chen
Two cases of gastroendoscopy-associated Acinetobacter baumannii (A. baumannii) bacteremia were discovered at the study hospital. The first case was a 66-year-old woman who underwent endoscopic retrograde cholangiopancreatography and endoscopic retrograde papillotomy, and then A. baumannii bacteremia occurred. The second case was a 70-year-old female who underwent endoscopic retrograde biliary drainage due to obstruction of intra-hepatic ducts, and bacteremia occurred due to polymicrobes (Esch...
Pérez Trallero, E; López Lopategui, C; Fernández Pérez, F
Shigella bacteremia is very uncommon, although it is known to occur in Shigella infection. Three cases of Shigella flexneri bacteremia are reported, two of them diagnosed at the Residencia Ntra. Sra. de Aránzazu of San Sebastián, and another at the Ciudad Sanitaria Francisco Franco of Barcelona. In spite of the frequency of Shigella infections in Spain, no cases of Shigella bacteriemia had been heretofore reported from our country. One of the patients was an alcoholic woman who died in coma and renal failure. The other two cases were children who had an uneventful recovery. Stool cultures were positive for Shigella flexneri in two of the three patients. In the third the bacillus could not be isolated from the stools in spite of three consecutive cultures.
Hilliard, Nicholaus J.; Schelonka, Robert L.; Waites, Ken B.
Bacillus cereus is an uncommon but potentially serious bacterial pathogen causing infections of the bloodstream, lungs, and central nervous system of preterm neonates. A case of bacteremia caused by B. cereus in a 19-day-old preterm neonate who was successfully treated with vancomycin, tobramycin, meropenem, and clindamycin is described. Implications for the diagnostic laboratory and clinicians when Bacillus species are detected in normally sterile sites are discussed, and the small numbers o...
Klug, Tejs Ehlers; Henriksen, Jens-Jacob; Rusan, Maria;
swabs, core tissue, and pus aspirates were analyzed by standard microbiological techniques. Results: Bacteremia was detected in 73% of patients during elective tonsillectomy compared to 56% during quinsy tonsillectomy (P ¼ .089, Fishers exact test). Significantly more blood culture bottles were positive...... prophylaxis recommendations to patients at high risk of infective endocarditis who are undergoing tonsillectomy. Methods: A prospective study was conducted on 80 patients undergoing elective tonsillectomy and 36 patients undergoing acute tonsillectomy due to peritonsillar abscess. Blood cultures, tonsillar...
Chen, Chang-Hua; Wu, Shun-Sheng; Huang, Chieh-Chen
Two cases of gastroendoscopy-associated Acinetobacter baumannii (A. baumannii) bacteremia were discovered at the study hospital. The first case was a 66-year-old woman who underwent endoscopic retrograde cholangiopancreatography and endoscopic retrograde papillotomy, and then A. baumannii bacteremia occurred. The second case was a 70-year-old female who underwent endoscopic retrograde biliary drainage due to obstruction of intra-hepatic ducts, and bacteremia occurred due to polymicrobes (Escherichia coli, viridans streptococcus, and A. baumannii). After a literature review, we suggest that correct gastroendoscopy technique and skill in drainage procedures, as well as antibiotic prophylaxis, are of paramount importance in minimizing the risk of gastroendoscopy-associated bacteremia.
Full Text Available Abstract In a previous study, we demonstrated prolonged length of hospital stay in cases of extended-spectrum beta-lactamase (ESBL-positive K. pneumoniae bacteremia compared to bacteremia cases due to E. coli (ESBL-positive and –negative and ESBL-negative K. pneumoniae. The overall mortality was significantly higher in bacteremia cases resulting from ESBL-positive pathogens but also in K. pneumoniae cases disregarding ESBL-production. In order to examine whether pathogen species rather than multidrug resistance might affect mortality risk, we reanalyzed our dataset that includes 1.851 cases of bacteremia.
Full Text Available Advances in Aeromonas taxonomy have led to the reclassification of aeromonads. Hereon, we aimed to re-evaluate the characteristics of Aeromonas bacteremia, including those of a novel species, Aeromonas dhakensis.A retrospective study of monomicrobial Aeromonas bacteremia at a medical center in southern Taiwan from 2004-2011 was conducted. Species identification was based on rpoB sequencing. Of bacteremia of 153 eligible patients, A. veronii (50 isolates, 32.7%, A. dhakensis (48, 31.4%, A. caviae (43, 28.1%, and A. hydrophila (10, 6.5% were the principal causative species. A. dhakensis and A. veronii bacteremia were mainly community-acquired and presented as primary bacteremia, spontaneous bacterial peritonitis, or skin and soft-tissue infection, whereas A. caviae was associated with hospital-onset bacteremia. The distribution of the AmpC β-lactamase and metallo-β-lactamase genes was species-specific: bla(AQU-1, bla(MOX, or bla(CepH was present in A. dhakensis, A. caviae, or A. hydrophila, respectively, and bla(CphA was present in A. veronii, A. dhakensis, and A. hydrophila. The cefotaxime resistance rates of the A. caviae, A. dhakensis, and A. hydrophila isolates were higher than that of A. veronii (39.5%%, 25.0%, and 30% vs. 2%, respectively. A. dhakensis bacteremia was linked to the highest 14-day sepsis-related mortality rate, followed by A. hydrophila, A. veronii, and A. caviae bacteremia (25.5%, 22.2%, 14.0%, and 4.7%, respectively; P = 0.048. Multivariate analysis revealed that A. dhakensis bacteremia, active malignancies, and a Pitt bacteremia score ≥ 4 was an independent mortality risk factor.Characteristics of Aeromonas bacteremia vary between species. A. dhakensis prevalence and its associated poor outcomes suggest it an important human pathogen.
Baum, Cathrin; Haslinger-Löffler, Bettina; Westh, Henrik;
Staphylococcus aureus is a major human pathogen responsible for increasing the prevalence of community- and hospital-acquired infections. Protein A (SpA) is a key virulence factor of S. aureus and is highly conserved. Sequencing of the variable-number tandem-repeat region of SpA (spa typing......) provides a rapid and reliable method for epidemiological studies. Rarely, non-spa-typeable S. aureus strains are encountered. The reason for this is not known. In this study, we characterized eight non-spa-typeable bacteremia isolates. Sequencing of the entire spa locus was successful for five strains...
Yamakawa, Kiyoshi; Yamagishi, Yuka; Miyata, Kenji; Shimomura, Yasuto; Iwata, Atsuko; Hori, Toshinori; Mikamo, Hiroshige; Okumura, Akihisa
We encountered 2 immunocompromised children complicated by Raoultella ornithinolytica bacteremia. One had received methylprednisolone pulse therapy for IgA nephropathy, and the other had leukopenia because of chemotherapy for leukemia. Both children had no specific symptoms, and R. ornithinolytica bacteremia was identified by routine blood culture. Both patients were successfully treated with antibiotic treatment.
Dai, Julia; Huen, Auris O; Kestenbaum, Lori A; Sarezky, Margaret D; Coughlin, Carrie C; Yan, Albert C
Achromobacter xylosoxidans is a rare, opportunistic infection most commonly encountered in immunocompromised patients during hospitalization. Primary uncomplicated bacteremia, catheter-associated infections, and pneumonia have been reported as the most common clinical presentations; skin and soft tissue infections from A. xylosoxidans are rare. We describe a case of A. xylosoxidans presenting as cellulitis and bacteremia in an immunocompromised patient.
Bayhan, Gulsum Iclal; Senel, Saliha; Tanir, Gonul; Ozkan, Sengul
Pseudomonas luteola has rarely been reported as a human pathogen. The clinical manifestations of P. luteola bacteremia and its susceptibility to antibiotics have not been characterized. This retrospective study was conducted at a 382-bed tertiary care center in Turkey. During the 9-year study period, 7 patients (5 females and 2 males) were diagnosed with P. luteola bacteremia. Six of these patients had hospital-acquired bacteremia, whereas 1 patient had community-acquired P. luteola infection. All patients had monomicrobial bacteremia. Antimicrobial susceptibility testing revealed that all strains of P. luteola were sensitive to amikacin, gentamicin, trimethoprim-sulfamethoxazole, and meropenem, and that all strains were resistant to piperacillin-tazobactam, aztreonam, and colistin. In conclusion, we believe that P. luteola can cause both community- and hospital-acquired bacteremia. Amikacin, gentamicin, trimethoprim-sulfamethoxazole, and meropenem were effective against P. luteola in the present study.
Full Text Available Staphylococcus (S. aureus is a common causative agent of bacterial endophthalmitis, a vision threatening complication of eye surgeries. The relative contribution of S. aureus virulence factors in the pathogenesis of endophthalmitis remains unclear. Here, we comprehensively analyzed the development of intraocular inflammation, vascular permeability, and the loss of retinal function in C57BL/6 mouse eyes, challenged with live S. aureus, heat-killed S. aureus (HKSA, peptidoglycan (PGN, lipoteichoic acid (LTA, staphylococcal protein A (SPA, α-toxin, and Toxic-shock syndrome toxin 1 (TSST1. Our data showed a dose-dependent (range 0.01 μg/eye to 1.0 μg/eye increase in the levels of inflammatory mediators by all virulence factors. The cell wall components, particularly PGN and LTA, seem to induce higher levels of TNF-α, IL-6, KC, and MIP2, whereas the toxins induced IL-1β. Similarly, among the virulence factors, PGN induced higher PMN infiltration. The vascular permeability assay revealed significant leakage in eyes challenged with live SA (12-fold and HKSA (7.3-fold, in comparison to other virulence factors (~2-fold and controls. These changes coincided with retinal tissue damage, as evidenced by histological analysis. The electroretinogram (ERG analysis revealed a significant decline in retinal function in eyes inoculated with live SA, followed by HKSA, SPA, and α-toxin. Together, these findings demonstrate the differential innate responses of the retina to S. aureus virulence factors, which contribute to intraocular inflammation and retinal function loss in endophthalmitis.
Cechinel, Angélica; Machado, Denise P.; Turra, Eduardo; Pereira, Dariane; dos Santos, Rodrigo P.; Rosa, Regis G.; Goldani, Luciano Z.
Background. Polymorphism of the accessory gene regulator group II (agr) in methicillin-resistant Staphylococcus aureus (MRSA) is predictive of vancomycin failure therapy. Nevertheless, the impact of group II agr expression on mortality of patients with severe MRSA infections is not well established. Objective. The goal of our study was to evaluate the association between agr polymorphism and all-cause in-hospital mortality among critically ill patients receiving vancomycin for nosocomial MRSA bacteremia. Methods. All patients with documented bacteremia by MRSA requiring treatment in the ICU between May 2009 and November 2011 were included in the study. Cox proportional hazards regression was performed to evaluate whether agr polymorphism was associated with all-cause in-hospital mortality. Covariates included age, APACHE II score, initial C-reactive protein plasma levels, initial serum creatinine levels, vancomycin minimum inhibitory concentration, vancomycin serum levels, and time to effective antibiotic administration. Results. The prevalence of group I and group II agr expression was 52.4% and 47.6%, respectively. Bacteremia by MRSA group III or group IV agr was not documented in our patients. The mean APACHE II of the study population was 24.3 (standard deviation 8.5). The overall cohort mortality was 66.6% (14 patients). After multivariate analysis, initial plasma C-reactive protein levels (P = 0.01), initial serum creatinine levels (P = 0.008), and expression of group II agr (P = 0.006) were positively associated with all-cause in-hospital mortality. Patients with bacteremia by MRSA with group II agr expression had their risk of death increased by 12.6 times when compared with those with bacteremia by MRSA with group I agr expression. Conclusion. Group II agr polymorphism is associated with an increase in mortality in critically ill patients with bacteremia by MRSA treated with vancomycin. PMID:27366180
Full Text Available Background. Polymorphism of the accessory gene regulator group II (agr in methicillin-resistant Staphylococcus aureus (MRSA is predictive of vancomycin failure therapy. Nevertheless, the impact of group II agr expression on mortality of patients with severe MRSA infections is not well established. Objective. The goal of our study was to evaluate the association between agr polymorphism and all-cause in-hospital mortality among critically ill patients receiving vancomycin for nosocomial MRSA bacteremia. Methods. All patients with documented bacteremia by MRSA requiring treatment in the ICU between May 2009 and November 2011 were included in the study. Cox proportional hazards regression was performed to evaluate whether agr polymorphism was associated with all-cause in-hospital mortality. Covariates included age, APACHE II score, initial C-reactive protein plasma levels, initial serum creatinine levels, vancomycin minimum inhibitory concentration, vancomycin serum levels, and time to effective antibiotic administration. Results. The prevalence of group I and group II agr expression was 52.4% and 47.6%, respectively. Bacteremia by MRSA group III or group IV agr was not documented in our patients. The mean APACHE II of the study population was 24.3 (standard deviation 8.5. The overall cohort mortality was 66.6% (14 patients. After multivariate analysis, initial plasma C-reactive protein levels (P=0.01, initial serum creatinine levels (P=0.008, and expression of group II agr (P=0.006 were positively associated with all-cause in-hospital mortality. Patients with bacteremia by MRSA with group II agr expression had their risk of death increased by 12.6 times when compared with those with bacteremia by MRSA with group I agr expression. Conclusion. Group II agr polymorphism is associated with an increase in mortality in critically ill patients with bacteremia by MRSA treated with vancomycin.
Hilliard, Nicholaus J; Schelonka, Robert L; Waites, Ken B
Bacillus cereus is an uncommon but potentially serious bacterial pathogen causing infections of the bloodstream, lungs, and central nervous system of preterm neonates. A case of bacteremia caused by B. cereus in a 19-day-old preterm neonate who was successfully treated with vancomycin, tobramycin, meropenem, and clindamycin is described. Implications for the diagnostic laboratory and clinicians when Bacillus species are detected in normally sterile sites are discussed, and the small numbers of infant infections proven to be due to this organism that have been described previously are reviewed.
Pedersen, Marie Kristine Jessen; Mackenhauer, Julie; Hvass, Anne Mette Sondrup Wulff;
Objective The objective of this study was to validate a previously published clinical decision rule for predicting a positive blood culture in emergency department (ED) patients with suspected infection on the basis of major and minor criteria and a total score (Shapiro et al., J Emerg Med, 2008......; 35:255–264). Methods This is a retrospective matched cohort study of adult ED patients with blood cultures obtained from 1 January 2011 through to 31 December 2011. ED patients with blood culture-confirmed bacteremia were matched 1 : 3 with patients with negative cultures. The outcome was ‘true...
de Jong, Eefje; Erkens-Hulshof, Sandra; van der Velden, Lieven B J; Voss, Andreas; Bosboom, Ron; Hodiamont, Caspar J; Wever, Peter C; Rentenaar, Rob J; Sturm, Patrick D
A case series of 14 patients with Raoultella bacteremia was compared with 28 Klebsiella oxytoca and 28 Klebsiella pneumoniae bacteremia cases. Forty-three percent of Raoultella bacteremia cases were associated with biliary tract disease, compared to 32% and 22% of patients with K. oxytoca and K. pneumoniae bacteremia, respectively.
Qureshi, Nadia K; Yin, Shaohui; Boyle-Vavra, Susan
Vancomycin is often the preferred treatment for invasive methicillin-resistant Staphylococcus aureus (MRSA) infection. With the increase in incidence of MRSA infections, the use of vancomycin has increased and, as feared, isolates of vancomycin-resistant Staphylococcus aureus (VRSA) have emerged. VRSA isolates have acquired the entercoccal vanA operon contained on transposon (Tn) 1546 residing on a conjugal plasmid. VraTSR is a vancomycin and β-lactam-inducible three-component regulatory system encoded on the S. aureus chromosome that modulates the cell-wall stress response to cell-wall acting antibiotics. Mutation in vraTSR has shown to increase susceptibility to β-lactams and vancomycin in clinical VISA strains and in recombinant strain COLVA-200 which expresses a plasmid borne vanA operon. To date, the role of VraTSR in vanA operon expression in VRSA has not been demonstrated. In this study, the vraTSR operon was deleted from the first clinical VRSA strain (VRS1) by transduction with phage harvested from a USA300 vraTSR operon deletion strain. The absence of the vraTSR operon and presence of the vanA operon were confirmed in the transductant (VRS1Δvra) by PCR. Broth MIC determinations, demonstrated that the vancomycin MIC of VRS1Δvra (64 µg/ml) decreased by 16-fold compared with VRS1 (1024 µg/ml). The effect of the vraTSR operon deletion on expression of the van gene cluster (vanA, vanX and vanR) was examined by quantitative RT-PCR using relative quantification. A 2-5-fold decreased expression of the vanA operon genes occured in strain VRS1Δvra at stationary growth phase compared with the parent strain, VRS1. Both vancomycin resistance and vancomycin-induced expression of vanA and vanR were restored by complementation with a plasmid harboring the vraTSR operon. These findings demonstrate that expression in S. aureus of the horizontally acquired enterococcal vanA gene cluster is enhanced by the staphylococcal three-component cell wall stress regulatory
Liu, Bo; Park, Saeyoung; Thompson, Christopher D; Li, Xue; Lee, Jean C
The capsular polysaccharide (CP) produced by Staphylococcus aureus is a virulence factor that allows the organism to evade uptake and killing by host neutrophils. Polyclonal antibodies to the serotype 5 (CP5) and type 8 (CP8) capsular polysaccharides are opsonic and protect mice against experimental bacteremia provoked by encapsulated staphylococci. Thus, passive immunotherapy using CP antibodies has been considered for the prevention or treatment of invasive antibiotic-resistant S. aureus infections. In this report, we generated monoclonal antibodies (mAbs) against S. aureus CP5 or CP8. Backbone specific mAbs reacted with native and O-deacetylated CPs, whereas O-acetyl specific mAbs reacted only with native CPs. Reference strains of S. aureus and a selection of clinical isolates reacted by colony immunoblot with the CP5 and CP8 mAbs in a serotype-specific manner. The mAbs mediated in vitro CP type-specific opsonophagocytic killing of S. aureus strains, and mice passively immunized with CP5 mAbs were protected against S. aureus bacteremia. Neither CP8-specific mAbs or polyclonal antibodies protected mice against bacteremia provoked by serotype 8 S. aureus clinical isolates, although these same antibodies did protect against a serotype 5 S. aureus strain genetically engineered to produce CP8. We detected soluble CP8 in culture supernatants of serotype 8 clinical isolates and in the plasma of infected animals. Serotype 5 S. aureus released significantly less soluble CP5 in vitro and in vivo. The release of soluble CP8 by S. aureus may contribute to the inability of CP8 vaccines or antibodies to protect against serotype 8 staphylococcal infections.
Goerke, Christiane; Fluckiger, Ursula; Steinhuber, Andrea; Bisanzio, Vittoria; Ulrich, Martina; Bischoff, Markus; Patti, Joseph M; Wolz, Christiane
The ability of Staphylococcus aureus to adapt to different environments is due to a regulatory network comprising several loci. Here we present a detailed study of the interaction between the two global regulators sae and sigmaB of S. aureus and their influence on virulence gene expression in vitro, as well as during device-related infection. The expression of sae, asp23, hla, clfA, coa, and fnbA was determined in strain Newman and its isogenic saeS/R and sigB mutants by Northern analysis and LightCycler reverse transcription-PCR. There was no indication of direct cross talk between the two regulators. sae had a dominant effect on target gene expression during device-related infection. SigmaB seemed to be less active throughout the infection than under induced conditions in vitro.
Yanan Wang; Mo Hu; Qian Liu; Juanxiu Qin; Yingxin Dai; Lei He; Tianming Li; Bing Zheng; Fan Zhou; Kaiwen Yu; Jingyuan Fang; Xiaoyun Liu; Michael Otto; Min Li
Novel Staphylococcus aureus clones continue to emerge that cause infections in otherwise healthy people. One example is the sequence type (ST) 398 lineage, which we show here is increasing in importance as a significant cause of community-associated (CA) human infections in China. We have a profound lack of understanding about what determines the considerable virulence potential of such newly emerging clones. Information about the contribution to virulence of the more recently discovered ESAT...
Papadimitriou-Olivgeri, I; Giormezis, N; Papadimitriou-Olivgeris, M; Zotou, A; Kolonitsiou, F; Koutsileou, K; Fligou, F; Marangos, M; Anastassiou, E D; Spiliopoulou, I
The significance of the number of coagulase-negative staphylococci (CNS)-positive blood cultures remains obscure in regards to determining true bacteremia versus contamination. The goal of this study was to determine the predictors of real CNS bloodstream infection among intensive care unit (ICU) patients. ICU patients with at least one CNS-positive blood culture were identified from the microbiology database. Biofilm formation was tested by glass tube and microtiter plate assay. mecA gene, ica operon genes (icaA, icaB, icaD), and adhesin genes (aap, bap, atlE, fbe, fnbA) were detected by polymerase chain reaction (PCR). CNS were recovered from 120 septic episodes, 20 of which were true CNS bacteremias, whereas from the remaining 100 episodes, the isolated CNS were characterized as contaminants. The number of positive blood cultures was significantly associated with true CNS bacteremia. Nineteen true bacteremic Staphylococcus epidermidis strains were compared to 38 contaminants. Biofilm synthesis was documented in 37 isolates associated with the presence of the ica operon (p = 0.048). There were 39, 26, 38, 21, and 10 strains positive for the presence of atlE, bap, fbe, aap, and fnbA genes, respectively. Rifampicin resistance, absence of severe sepsis, number of S. epidermidis-positive blood cultures, and absence of the bap gene were independently associated with true S. epidermidis bacteremia as compared to contaminant strains. The number of positive blood cultures is associated with true CNS bacteremia. The presence of adhesin genes may play a role in differentiating true infection from contamination, whereas absence of the bap gene is associated with true S. epidermidis bacteremia.
Alice G Cheng
Full Text Available The bacterial pathogen Staphylococcus aureus seeds abscesses in host tissues to replicate at the center of these lesions, protected from host immune cells via a pseudocapsule. Using histochemical staining, we identified prothrombin and fibrin within abscesses and pseudocapsules. S. aureus secretes two clotting factors, coagulase (Coa and von Willebrand factor binding protein (vWbp. We report here that Coa and vWbp together are required for the formation of abscesses. Coa and vWbp promote the non-proteolytic activation of prothrombin and cleavage of fibrinogen, reactions that are inhibited with specific antibody against each of these molecules. Coa and vWbp specific antibodies confer protection against abscess formation and S. aureus lethal bacteremia, suggesting that coagulases function as protective antigens for a staphylococcal vaccine.
Full Text Available Abstract Background Reports of the etiology of bacteremia in children from Nigeria are sparse and have been confounded by wide spread non-prescription antibiotic use and suboptimal laboratory culture techniques. We aimed to determine causative agents and underlying predisposing conditions of bacteremia in Nigerian children using data arising during the introduction of an automated blood culture system accessed by 7 hospitals and clinics in the Abuja area. Methods Between September 2008 and November 2009, we enrolled children with clinically suspected bacteremia at rural and urban clinical facilities in Abuja or within the Federal Capital Territory of Nigeria. Blood was cultured using an automated system with antibiotic removing device. We documented clinical features in all children and tested for prior antibiotic use in a random sample of sera from children from each site. Results 969 children aged 2 months-5 years were evaluated. Mean age was 21 ± 15.2 months. All children were not systematically screened but there were 59 (6% children with established diagnosis of sickle cell disease and 42 (4.3% with HIV infection. Overall, 212 (20.7% had a positive blood culture but in only 105 (10.8% were these considered to be clinically significant. Three agents, Staphylococcus aureus (20.9%, Salmonella typhi (20.9% and Acinetobacter (12.3% accounted for over half of the positive cultures. Streptococcus pneumoniae and non-typhi Salmonellae each accounted for 7.6%. Although not the leading cause of bacteremia, Streptococcus pneumoniae was the single leading cause of all deaths that occurred during hospitalization and after hospital discharge. Conclusion S. typhi is a significant cause of vaccine-preventable morbidity while S. pneumoniae may be a leading cause of mortality in this setting. This observation contrasts with reports from most other African countries where non-typhi Salmonellae are predominant in young children. Expanded surveillance is
Nielsen, P B; Hansen, R I; Madsen, O G;
A bacteriological survey of 50 consecutive patients undergoing transurethral resection of the prostate was performed. Preoperatively, 28% of the patients had asymptomatic bacteriuria. In the postoperative period, 46% of all the patients developed transient bacteremia. A significantly higher rate...... of bacteremia was found in patients with hypertrophy of the prostate than in those with cancer of the prostate and in patients undergoing long-lasting surgical intervention. Patients who developed bacteremia due to pathogenic bacteria were hospitalized for a significantly longer period of time....
Full Text Available BACKGROUND: Little is known about the epidemiology of nosocomial bloodstream infections in public hospitals in developing countries. We evaluated trends in incidence of hospital-acquired bacteremia (HAB and healthcare-associated bacteremia (HCAB and associated mortality in a developing country using routinely available databases. METHODS: Information from the microbiology and hospital databases of 10 provincial hospitals in northeast Thailand was linked with the national death registry for 2004-2010. Bacteremia was considered hospital-acquired if detected after the first two days of hospital admission, and healthcare-associated if detected within two days of hospital admission with a prior inpatient episode in the preceding 30 days. RESULTS: A total of 3,424 patients out of 1,069,443 at risk developed HAB and 2,184 out of 119,286 at risk had HCAB. Of these 1,559 (45.5% and 913 (41.8% died within 30 days, respectively. Between 2004 and 2010, the incidence rate of HAB increased from 0.6 to 0.8 per 1,000 patient-days at risk (p<0.001, and the cumulative incidence of HCAB increased from 1.2 to 2.0 per 100 readmissions (p<0.001. The most common causes of HAB were Acinetobacter spp. (16.2%, Klebsiella pneumoniae (13.9%, and Staphylococcus aureus (13.9%, while those of HCAB were Escherichia coli (26.3%, S. aureus (14.0%, and K. pneumoniae (9.7%. There was an overall increase over time in the proportions of ESBL-producing E. coli causing HAB and HCAB. CONCLUSIONS: This study demonstrates a high and increasing incidence of HAB and HCAB in provincial hospitals in northeast Thailand, increasing proportions of ESBL-producing isolates, and very high associated mortality.
Lam, Philip W; Salit, Irving E
Raoultella planticola is a Gram-negative bacillus commonly found in water, soil and aquatic environments. There have only been 16 cases of R planticola infection documented in the literature to date. R planticola possesses the ability to convert histidine to histamine and can produce symptoms of scombroid poisoning when poorly prepared seafood is consumed in large amounts. The present report describes a case involving a 56-year-old woman who presented with R planticola bacteremia and symptoms consistent with cholangitis four days after consuming a seafood salad containing squid and octopus. She was successfully treated with intravenous ceftriaxone followed by oral ciprofloxacin. Recent chemotherapy, proton pump inhibitor use and altered biliary flow secondary to hepatic metastases may have been contributing factors to the pathogenesis of disease.
Møller, Holger Jon; Moestrup, Søren K; Weis, Nina
OBJECTIVE: Soluble CD163 (sCD163) is a new macrophage-specific serum marker. This study investigated sCD163 and other markers of macrophage activation (neopterin, ferritin, transcobalamin, and soluble urokinase plasminogen activator receptor [suPAR]) as prognostic factors in patients with pneumoc......OBJECTIVE: Soluble CD163 (sCD163) is a new macrophage-specific serum marker. This study investigated sCD163 and other markers of macrophage activation (neopterin, ferritin, transcobalamin, and soluble urokinase plasminogen activator receptor [suPAR]) as prognostic factors in patients...... on the probability of survival when sCD163 and CRP were known (p = .25). CONCLUSIONS: Macrophage marker response in pneumococcal bacteremia was compromised in old age. In patients disease outcome....
Philip W Lam
Full Text Available Raoultella planticola is a Gram-negative bacillus commonly found in water, soil and aquatic environments. There have only been 16 cases of R planticola infection documented in the literature to date. R planticola possesses the ability to convert histidine to histamine and can produce symptoms of scombroid poisoning when poorly prepared seafood is consumed in large amounts. The present report describes a case involving a 56-year-old woman who presented with R planticola bacteremia and symptoms consistent with cholangitis four days after consuming a seafood salad containing squid and octopus. She was successfully treated with intravenous ceftriaxone followed by oral ciprofloxacin. Recent chemotherapy, proton pump inhibitor use and altered biliary flow secondary to hepatic metastases may have been contributing factors to the pathogenesis of disease.
di Meo, Nicola; Stinco, Giuseppe; Gubertini, Nicoletta; Patriarca, Maria Martina; Trevisan, Giusto
In recent years, group G Streptococcus has been reported with increasing frequency as the cause of a variety of human infections. Underlying host factors such as immunosuppression, malignancy, diabetes mellitus, and rheumatoid arthritis may be predisposing conditions leading to infection. Toxic involvement and post-streptococcal sequalae, once believed to be exclusive to infections caused by group A Streptococcus, are now known to occur following acute group G Streptococcus and group C Streptococcus infections. We report on a case of group G Streptococcus bacteremia and recurrent cellulitis with toxic involvement. Patient blood cultures were always negative for β-hemolytic Streptococci in all the recurrences, except during the last one. Antibiotic therapy based on antibiogram quickly resolved the infection. A regimen of intramuscular injection of 1.2 million units of benzathine penicillin every 15 days for one year prevented recurrences of cellulitis.
Dicpinigaitis, Peter V.; De Aguirre, Manuel; Divito, Joseph
Infection with Enterococcus hirae has rarely been reported in humans but is not uncommon in mammals and birds. We describe a case of Enterococcus hirae bacteremia associated with acute pancreatitis, acute cholecystitis, and septic shock responsive to antibiotic therapy and supportive critical care management. Unique aspects of this case of Enterococcus hirae bacteremia are its association with acute pancreatitis and its geographical origin. To our knowledge, this is the first report of Enterococcus hirae bacteremia occurring in a patient in the United States. Although human infection with this organism appears to be rare, all cases reported to date describe bacteremia associated with severe and life-threatening illness. Thus, physicians need to be cognizant of the clinical significance of this heretofore little recognized pathogen. PMID:26417465
Peter V. Dicpinigaitis
Full Text Available Infection with Enterococcus hirae has rarely been reported in humans but is not uncommon in mammals and birds. We describe a case of Enterococcus hirae bacteremia associated with acute pancreatitis, acute cholecystitis, and septic shock responsive to antibiotic therapy and supportive critical care management. Unique aspects of this case of Enterococcus hirae bacteremia are its association with acute pancreatitis and its geographical origin. To our knowledge, this is the first report of Enterococcus hirae bacteremia occurring in a patient in the United States. Although human infection with this organism appears to be rare, all cases reported to date describe bacteremia associated with severe and life-threatening illness. Thus, physicians need to be cognizant of the clinical significance of this heretofore little recognized pathogen.
Nielsen, Stig Lønberg
for an overall incidence rate of 215.7 per 100,000 person years including 99.0 for community-acquired, 50.0 for healthcare-associated and 66.7 for nosocomial bacteremia. The overall incidence rate decreased by 23.3% (95% CI, 17.8%-28.4%) from year 2000 to 2008 (3.3% per year, prates...... of community-acquired bacteremia (3.7% per year, p year, pincidence rate of healthcare-associated bacteremia remained more or less stable throughout the study period (p=0.17). The crude incidence rates decreased for Escherichia coli, Staphylococcus......-time bacteremias per admission for an overall incidence of 14.2 per 1000 admissions and 23.6 per 10,000 bed days; highest for males, elderly individuals (> 65 years), and patients initially admitted to the Departments of Hematology, Nephrology, Internal Medicine, Urology or Oncology. The daily incidence...
Full Text Available OXA-48-producing isolates were identified in approximately 4% and less than 1% of ESBL-producing and non-ESBL-producing E. coli and K. pneumoniae causing bacteremia at the largest tertiary hospital in Abu Dhabi.
Louwen, R.; Baarlen, van P.; Vliet, van A.H.M.; Belkum, van A.; Hays, J.P.; Endtz, H.P.
Bacteria belonging to the species Campylobacter are the most common cause of bacterial diarrhoea in humans. The clinical phenotype associated with Campylobacter infections ranges from asymptomatic conditions to severe colitis and bacteremia. In susceptible patients, Campylobacter infections are asso
Madsen, Ida Ringsborg; Justesen, Ulrik Stenz
Animal bite wounds are often infected with bacteria from the animal's oral flora. We report what we believe to be the first case of bacteremia with Bacteroides pyogenes resulting from an infected cat bite.......Animal bite wounds are often infected with bacteria from the animal's oral flora. We report what we believe to be the first case of bacteremia with Bacteroides pyogenes resulting from an infected cat bite....
Hofmans, M; Boel, A; Van Vaerenbergh, K; De Beenhouwer, H
Staphylococcus saprophyticus is a well-known cause of uncomplicated urinary tract infections, especially in young and sexually active women. Presence in blood cultures is rare and often attributed to contamination. When bacteremia is significant, it occurs mostly in patients with hematologic malignancies and is predominantly catheter-related. However, we describe a case of significant bacteremia with S. saprophyticus associated with urinary tract infection after extracorporeal shock wave lithotripsy of an ureterolithiasis in an otherwise healthy patient.
Bruun, B; Bangsborg, Jette Marie; Hovgaard, D;
of coagulase-negative staphylococci was higher in the latter period while that of Staphylococcus aureus was lower. Of 67 strains of Enterobacteriaceae tested for an aminoglycoside, 6% were found to be resistant, whereas 8% of 48 Enterobacteriaceae strains were found to be cefotaxime resistant. Methicillin...
Will A. McGuinness
Full Text Available Staphylococcus aureus causes many types of infections, ranging from self-resolving skin infections to severe or fatal pneumonia. Human innate immune cells, called polymorphonuclear leukocytes (PMNs or neutrophils, are essential for defense against S. aureus infections. Neutrophils are the most prominent cell type of the innate immune system and are capable of producing non-specific antimicrobial molecules that are effective at eliminating bacteria. Although significant progress has been made over the past few decades, our knowledge of S. aureus-host innate immune system interactions is incomplete. Most notably, S. aureus has the capacity to produce numerous molecules that are directed to protect the bacterium from neutrophils. Here we review in brief the role played by neutrophils in defense against S. aureus infection, and correspondingly, highlight selected S. aureus molecules that target key neutrophil functions.
Caporarello, N; Salmeri, M; Scalia, M; Motta, C; Parrino, C; Frittitta, L; Olivieri, M; Toscano, M A; Anfuso, C D; Lupo, G
Cytosolic PLA2 (cPLA2) and Ca(2+)-independent PLA2 (iPLA2) play a significant role in insulin β-cells secretion. Bacterial infections may be responsible of the onset of diabetes. The mechanism by which Staphylococcus aureus infection of INS-1 cells alters glucose-induced insulin secretion has been examined. After acute infection, insulin secretion and PLA2 activities significantly increased. Moreover, increased expressions of phospho-cPLA2, phospho-PKCα and phospho-ERK 1/2 were observed. Chronic infection causes a decrease in insulin release and a significant increase of iPLA2 and COX-2 protein expression. Moreover, insulin secretion in infected cells could be restored using specific siRNAs against iPLA2 isoform and specific COX-2 inhibitor.
Adrelírio J. R. Gonçalves
Full Text Available São apresentados 31 casos de bacteremia por gram-negativos, assunto que vem merecendo muita atenção dos pesquisadores nos últimos anos. Os organismos etiológicos mais importantes que apareceram em igualdade de freqüência foram Escherichia coli e Klebsiella-Aerobacter, sendo responsáveis por 58% do total das infecções, seguidos por Pseudomonas. A porta de entrada mais freqüente foi o trato urinário em 61,3% dos casos. A infecção foi mais comum no sexo masculino e a faixa etária de 50 a 60 anos predominou. O uso prévio de antibióticos foi um fator predisponente muito importante, seguido pelo uso de esteróides e citostáticos. As principais doenças predisponentes foram diabetes mellitus e neoplasias malignas. Os principais fatores precipitantes foram a manipulação do aparelho urinário, com infecção prévia ou desencadeada, cirurgia do aparelho digestivo, uronatia obstrutiva e obstrução biliar. As principais manifestações clínicas foram a presença de febre, calafrios e hipotensão arterial. A complicação mais freqüente foi o choque bacteriano que incidiu em 58% dos casos, aproximadamente três vêzes aquela relatada na literatura. As outras foram a insuficiência renal aguda, superinfecção e infecção pulmonar metastática. Considerações terapêuticas gerais e esquemas de antibióticos são propostos para estes casos. A mortalidade da bacteremia simples foi de 30,7% e quando associada ao choque elevou-se para 72,2% . As infecções por Pseudomonas foram 100% fatais.
Full Text Available Ventilator Associated Pneumonia (VAP is second most common cause of nosocomial infection. It also increases length of stay in hospital & cost for the patient. The American Thoracic Society guidelines for Hospital Acquired Pneumonia recognize that when bronchoscopy is not performed blood cultures may be of value both to isolate an etiologic agent & define severity. Aim: The present study was carried out to measure the prevalence of bacteremia in pt. with VAP. Methodology: In this prospective study 100 patients aged 0-12 years, admitted in ICU & put on ventilator at S.S.G.Hospital, Vadodara from 1st Sep. 2010 to 31st September 2011 were enrolled. The Endotracheal secretion culture & Blood culture were performed after 48hrs of ventilation. The samples were processed as per standard microbiological methods. In case of ET secretion culture, >106 cfu/ml was considered significant for the presence of bacteremia. Result: Of total 100 patients, 85 were Endotracheal secretion culture positive. Blood culture was positive in 38 of these 85 patients. Out of these 38 patients 30 (79% patients showed the same organism as was recovered from the Endotracheal secretion culture. VAP was developed in 85% of patients (85 of 100 & bacteremia was present in 44% of VAP patients but 30 out of 38 (79% cases of bacteremia were of pulmonary origin. Conclusion: The presence of Bacteremia in the patients with Hospital Acquired Pneumonia is considered to have important role for defining the aetiology. [National J of Med Res 2011; 1(2.000: 23-26
CHEN Rong; YAN Zhong-qiang; FENG Dan; LUO Yan-ping; WANG Lei-li; SHEN Ding-xia
Background Previous studies have different viewpoints about the clinical impact of methicillin resistance on mortality of hospital-acquired bloodstream infection (BSI) patients with Staphylococcus aureus (S.aureus).The objective of this study was to investigate the mortality of hospital-acquired BSI with S.aureus in a military hospital and analyze the risk factors for the hospital mortality.Methods A retrospective cohort study was performed in patients admitted to the biggest military tertiary teaching hospital in China between January 2006 and May 2011.All included patients had clinically significant nosocomial BSI with S.aureus.Multivariate Logistic regression analysis was used to identify the risk factors for hospital mortality of patients with S.aureus BSI.Results One hundred and eighteen patients of more than one year old were identified as clinically and microbiologically confirmed nosocomial bacteraemia due to S.aureus,and 75 out of 118 patients were infected with methicillin-resistant S.aureus (MRSA).The overall mortality of nosocomial S.aureus BSI was 28.0％.Methicillin resistance in S.aureus bacteremia was associated with significant increase in the length of hospitalization and high proportion of inappropriate empirical antibiotic treatment.After Logistic regression analysis,the severity of clinical manifestations (APACHE Ⅱ score) (odds ratio (OR) 1.22,95％ confidence interval (CI) 1.12-1.34) and inadequacy of empirical antimicrobial therapy (OR 0.25,95％ CI 0.09-0.69) remained as risk factors for hospital mortality.Conclusions Nosocomial S.aureus BSI was associated with high in-hospital mortality.Methicillin resistance in S.aureus has no significant impact on the outcome of patients with staphylococcal bacteremia.Proper empirical antimicrobial therapy is very important to the prognosis.
Full Text Available Endometritis is commonly caused by pathogenic microorganisms, including Staphylococcus aureus (S. aureus. Piperine, which is a natural medicine, has shown a variety of biological activities. To explore the effect and mechanism of piperine on S. aureus endometritis, a mouse model of S. aureus endometritis was successfully established in the present study. Histopathological changes were observed with H&E staining, cytokines were analyzed by ELISA, mRNA was analyzed by qPCR, and proteins were detected by western blot. The results showed that piperine could significantly alleviate inflammatory injury in S. aureus endometritis. The qPCR and ELISA results showed that piperine effectively reduced the S. aureus-induced overexpression of TNF-α, IL-1β, and IL-6 but increased the expression of IL-10. The S. aureus-induced inflammation was related to TLR-2 and TLR-4 because the results showed that their expression was increased in S. aureus infection but then decreased with piperine treatment. To further confirm that piperine caused an anti-inflammatory response by targeting NF-κB and MAPKs, the expression of I-κB, p65, p38, ERK, and JNK was measured. The phosphorylation of I-κB, p65, p38, ERK, and JNK was inhibited by piperine in a dose-dependent manner. All of the results indicated that piperine may be a potential anti-inflammatory drug both in endometritis and in other S. aureus-induced diseases.
Full Text Available Abstract Background There is limited information about the effect of diabetes on the prognosis of patients with bacterial infections. We performed a retrospective cohort study to investigate possible correlations between diabetes and prognosis in patients with Enterobacteriaceae bacteremia. Methods We reviewed the medical charts of 1112 patients who were treated at a community teaching hospital for Enterobacteriaceae bacteremia from January 1997 through June 2007. Factors associated with in-hospital mortality were analyzed by logistic regression analysis. Results Among the 1112 patients with Enterobacteriaceae bacteremia, 181 (16.3% were diabetic patients; 90 patients (8.1% died while in the hospital. Compared to non-diabetic patients, diabetic patients were older (75.4 ± 11.9 years vs. 70 ± 16.6 years, p p = 0.39]. In a multivariate analysis, the variables associated with in-hospital mortality were age, the origin of the bacteremia, and the presence of immunosuppression. Diabetes was not associated with outcome. Conclusion In this cohort of patients with Enterobacteriaceae bacteremia, diabetes was not associated with a poorer prognosis.
Galbusera, Elena; Renzoni, Adriana; Andrey, Diego O.; Monod, Antoinette; Barras, Christine; Tortora, Paolo; Polissi, Alessandra; Kelley, William L.
An initial response of Staphylococcus aureus to encounter with cell wall-active antibiotics occurs by transmembrane signaling systems that orchestrate changes in gene expression to promote survival. Histidine kinase two-component sensor-response regulators such as VraRS contribute to this response. In this study, we examined VraS membrane sensor phosphotransfer signal transduction and explored the genetic consequences of disrupting signaling by engineering a site-specific vraS chromosomal mutation. We have used in vitro autophosphorylation assay with purified VraS[64-347] lacking its transmembrane anchor region and tested site-specific kinase domain histidine mutants. We identified VraS H156 as the probable site of autophosphorylation and show phosphotransfer in vitro using purified VraR. Genetic studies show that the vraS(H156A) mutation in three strain backgrounds (ISP794, Newman, and COL) fails to generate detectable first-step reduced susceptibility teicoplanin mutants and severely reduces first-step vancomycin mutants. The emergence of low-level glycopeptide resistance in strain ISP794, derived from strain 8325 (ΔrsbU), did not require a functional σB, but rsbU restoration could enhance the emergence frequency supporting a role for this alternative sigma factor in promoting glycopeptide resistance. Transcriptional analysis of vraS(H156A) strains revealed a pronounced reduction but not complete abrogation of the vraRS operon after exposure to cell wall-active antibiotics, suggesting that additional factors independent of VraS-driven phosphotransfer, or σB, exist for this promoter. Collectively, our results reveal important details of the VraRS signaling system and predict that pharmacologic blockade of the VraS sensor kinase will have profound effects on blocking emergence of cell wall-active antibiotic resistance in S. aureus. PMID:21173175
Jong, Eefje de; Erkens-Hulshof, S.; Velden, L.B. van der; Voss, A.; Bosboom, R.; Hodiamont, C.J.; Wever, P.C.; Rentenaar, R.J.; Sturm, P.D.J.
A case series of 14 patients with Raoultella bacteremia was compared with 28 Klebsiella oxytoca and 28 Klebsiella pneumoniae bacteremia cases. Forty-three percent of Raoultella bacteremia cases were associated with biliary tract disease, compared to 32% and 22% of patients with K. oxytoca and K. pne
Transient bacteremia is induced by adenoidectomy when the integrity of the nasopharyngeal membrane is broken. The aim of this study was to determine the incidence of bacteremia in patients undergoing adenoidectomy, to identify the causative organisms, and to compare the incidences of bacteremia between the two techniques suction diathermy and curettage.
Full Text Available Morganella morganii is rarely isolated from nosocomial infections. However, postoperative infections due to Morganella spp. were documented in literature and eye involvements of the infections usually result in severe sequels. We present a severe case infection, which was caused by M. morganii subsp. morganii, firstly appearing as conjunctivitis and complicated by bacteremia. The infectious agent isolated from both conjunctival and consecutive blood cultures. Identification and anti- microbial susceptibility tests were performed with the Vitek 2® automated system. The isolate was resistant to cephalosporins and carbapenems and it had ability to produce extended spectrum beta-lactamases. Patient was successfully treated with intravenous ciprofloxacin according to susceptibility test results. This is the first report of M. morganii infection detected as a local infection then complicated by bacteremia. Keywords: Morganella morganii, conjunctivitis, bacteremia, ciprofloxacin
Nielsen, Anne Lerberg; Thomassen, Anders; Hess, Søren;
We report incidental FDG PET/CT findings of deep venous thrombosis and pulmonary embolism in a patient with bacteremia. In this patient, diagnosis of thromboembolism was not considered until FDG PET/CT imaging was performed, and the findings prompted immediate anticoagulant therapy. The role of FDG...... PET/CT in venous thromboembolism is not yet well established, but the potential benefit must be kept in mind when interpreting FDG PET/CT images regardless of the underlying disease....
Haslinger, Bettina; Strangfeld, Katrin; Peters, Georg; Schulze-Osthoff, Klaus; Sinha, Bhanu
Staphylococcus aureus infections can result in septic and toxic shock with depletion of immune cells and massive cytokine production. Recently, we showed that, in S. aureus-infected Jurkat T cells, alpha-toxin is the major mediator of caspase activation and apoptosis. Here, we investigated the mecha
Funada, H; Uotani, C; Machi, T; Matsuda, T; Nonomura, A
Bacillus cereus, which used to be considered non-pathogenic, was isolated from the blood of a patient with acute leukemia who was receiving intensive chemotherapy. Fatal bacteremia developed with a clinical syndrome of acute gastroenteritis, followed by both meningoencephalitis with subarachnoid hemorrhage and multiple liver abscesses probably caused by infective vasculitis. Surveillance stool cultures revealed colonization with the organism prior to the onset of diarrhea, and repetitive blood cultures were found to be positive. Thus, this case suggested some new important clinicopathologic features of true B. cereus bacteremia complicating acute leukemia.
Domínguez, H.; Vogel, Birte Fonnesbech; Gram, Lone;
The first Danish cases of Shewanella alga bacteremia in two patients with chronic lower leg ulcers are reported. Both patients were admitted to the hospital during the same month of a very warm summer and had been exposed to the same marine environment, thereby suggesting the same source of infec......The first Danish cases of Shewanella alga bacteremia in two patients with chronic lower leg ulcers are reported. Both patients were admitted to the hospital during the same month of a very warm summer and had been exposed to the same marine environment, thereby suggesting the same source......'Etoile, France), but further genetic and physiological analyses identified them as Shewanella alga....
Conclusions: Plasma endotoxin was more related to GN than to Gram-positive bacteremia, and that endotoxin level was species dependent, but PCT level remained relatively more stable within the GN bacteria caused bacteremia. Both GN and positive bacteria caused bacteremia in the ICU patients in different regions of China. And PCT is a more valuable biomarker than endotoxin in the diagnosis of bacteremia.
Staphylococcus aureus and Pregnancy In every pregnancy, a woman starts out with a 3-5% chance of having a ... This sheet talks about whether exposure to staphylococcus aureus may increase the risk for birth defects over ...
Haslund, P; Bangsgaard, N; Jarløv, J O
BACKGROUND: The role of bacterial infections in hand eczema (HE) remains to be assessed. OBJECTIVES: To determine the prevalence of Staphylococcus aureus in patients with HE compared with controls, and to relate presence of S. aureus, subtypes and toxin production to severity of HE. METHODS......: Bacterial swabs were taken at three different visits from the hand and nose in 50 patients with HE and 50 controls. Staphylococcus aureus was subtyped by spa typing and assigned to clonal complexes (CCs), and isolates were tested for exotoxin-producing S. aureus strains. The Hand Eczema Severity Index...... was used for severity assessment. RESULTS: Staphylococcus aureus was found on the hands in 24 patients with HE and four controls (P hands...
VanEperen, Alison S; Segreti, John
Methicillin-resistant Staphylococcus aureus (MRSA) continues to be an important pathogen worldwide, with high prevalence of infection in both community and hospital settings. Timely and appropriate choice of empirical therapy in the setting of MRSA infection is imperative due to the high rate of associated morbidity and mortality with MRSA infections. Initial choices should be made based on the site and severity of the infection, most notably moderate skin and soft tissue infections which may be treated with oral antibiotics (trimethoprim-sulfamethoxazole, clindamycin, doxycycline/minocycline, linezolid) in the outpatient setting, versus choice of parenteral therapy in the inpatient setting of more invasive or severe disease. Though the current recommendations continue to strongly rely on vancomycin as a standard empiric choice in the setting of severe/invasive infections, alternative therapies exist with studies supporting their non-inferiority. This includes the use of linezolid in pneumonia and severe skin and skin structure infections (SSSI) and daptomycin for MRSA bacteremia, endocarditis, SSSIs and bone/joint infections. Additionally, concerns continue to arise in regards to vancomycin, such as increasing isolate MICs, and relatively high rates of clinical failures with vancomycin. Thus, the growing interest in vanomycin alternatives, such as ceftaroline, ceftobribole, dalbavancin, oritavancin, and tedizolid, and their potential role in treating MRSA infections.
Sasahara, T; Hayashi, S; Morisawa, Y; Sakihama, T; Yoshimura, A; Hirai, Y
We describe an outbreak of Bacillus cereus bacteremia that occurred at Jichi Medical University Hospital in 2006. This study aimed to identify the source of this outbreak and to implement appropriate control measures. We reviewed the charts of patients with blood cultures positive for B. cereus, and investigated B. cereus contamination within the hospital environment. Genetic relationships among B. cereus isolates were analyzed. Eleven patients developed B. cereus bacteremia between January and August 2006. The hospital linens and the washing machine were highly contaminated with B. cereus, which was also isolated from the intravenous fluid. All of the contaminated linens were autoclaved, the washing machine was cleaned with a detergent, and hand hygiene was promoted among the hospital staff. The number of patients per month that developed new B. cereus bacteremia rapidly decreased after implementing these measures. The source of this outbreak was B. cereus contamination of hospital linens, and B. cereus was transmitted from the linens to patients via catheter infection. Our findings demonstrated that bacterial contamination of hospital linens can cause nosocomial bacteremia. Thus, blood cultures that are positive for B. cereus should not be regarded as false positives in the clinical setting.
John, Anna B; Razak, Eissa A S A; Razak, Emad E M H; Al-Naqeeb, Niran; Dhar, Rita
Although often regarded as a contaminant, Bacillus spp. have been implicated in serious systemic infections. The incidence of such infections is low with only a few cases reported in the literature. We describe the clinical course of early-onset Bacillus cereus bacteremia in a preterm neonate who was successfully treated with vancomycin.
van der Vusse, M. L.; van Son, W. J.; Ott, A.; Manson, W.
Here we present a case report of a 41-year-old woman suffering from high fever and bacteremia due to Helicobacter canis, 11months after kidney transplantation. Identification of H.canis was achieved by 16s rDNA sequence analysis of a positive blood culture. The patient was restored fully to health a
Jeon, Yong Duk; Jeong, Woo Yong; Kim, Moo Hyun; Jung, In Young; Ahn, Mi Young; Ann, Hea Won; Ahn, Jin Young; Han, Sang Hoon; Choi, Jun Yong; Song, Young Goo; Kim, June Myung; Ku, Nam Su
Abstract Stenotrophomonas maltophilia is a nosocomial pathogen associated with high morbidity and mortality, particularly in immunocompromised or critically ill patients. In this study, we investigated the risk factors for mortality in patients with S. maltophilia bacteremia. Retrospectively, medical records from all patients with S. maltophilia bacteremia between December 2005 and 2014 at Severance Hospital, a 2000-bed tertiary care hospital in Seoul, Korea, were reviewed. Analysis was performed to identify factors associated with 28-day mortality. In total, 142 bacteremia patients were enrolled in this study. The overall 28-day mortality rate was 36.6%. Based on the univariate analysis, hematologic malignancy (P = 0.015), Sepsis-related Organ Failure Assessment (SOFA) score (P < 0.001) and the removal of a central venous catheter (CVC) (P = 0.040) were significantly related to mortality. In the intensive care unit patients, the Acute Physiology and Chronic Health Evaluation II score (P = 0.001) also had significance. Based on the multivariate analysis, the SOFA score (odds ratio [OR] = 1.323; 95% confidence interval [CI]: 1.159, 1.509; P < 0.001) and removal of the CVC (OR = 0.330; 95% CI: 0.109, 0.996; P = 0.049) were independent factors associated with mortality. Our results suggest that removing a CVC may considerably reduce mortality in patients with S. maltophilia bacteremia. PMID:27495046
Opota, Onya; Ney, Barbara; Zanetti, Giorgio; Jaton, Katia; Greub, Gilbert; Prod'hom, Guy
We report for the first time a case of bacteremia caused by Comamonas kerstersii in a 65-year-old patient with sign of diverticulosis. In addition, we review the isolation of Comamonas sp. and related organisms in our hospital over 25 years.
Vähäkuopus, Susanna; Vuopio-Varkila, Jaana; Vuento, Risto; Syrjänen, Jaana
We conducted a retrospective population-based study of 140 episodes of Streptococcus dysgalactiae subsp. equisimilis bacteremia occurring in Finland during 1995–2004. Rare emm types were associated with more severe disease and increased mortality rates. Skin and soft tissue infections were more frequent clinical signs among cases caused by common emm types. PMID:20409380
Rantala, Sari; Vahakuopus, Susanna; Vuopio-Varkila, Jaana; Vuento, Risto; Syrjanen, Jaana
We conducted a retrospective population-based study of 140 episodes of Streptococcus dysgalactiae subsp. equisimilis bacteremia occurring in Finland during 1995-2004. Rare emm types were associated with more severe disease and increased mortality rates. Skin and soft tissue infections were more frequent clinical signs among cases caused by common emm types.
Rantala, Sari; Vähäkuopus, Susanna; Vuopio-Varkila, Jaana; Vuento, Risto; Syrjänen, Jaana
We conducted a retrospective population-based study of 140 episodes of Streptococcus dysgalactiae subsp. equisimilis bacteremia occurring in Finland during 1995–2004. Rare emm types were associated with more severe disease and increased mortality rates. Skin and soft tissue infections were more frequent clinical signs among cases caused by common emm types.
Dahl, Anders; Lauridsen, Trine K; Arpi, Magnus;
BACKGROUND: The NOVA score is a recently developed diagnostic tool to identify patients with increased risk of infective endocarditis (IE) among patients with Enterococcus faecalis (EF) bacteremia. We aim to validate an adapted version of the NOVA score and to identify risk factors for IE...
Mau, Nicole; Ross, Lawrence A
A case of Raoultella ornithinolytica bacteremia in an infant with visceral heterotaxy is reported. Physical examination was remarkable for markedly red skin flushing, not unlike that seen during histamine fish poisoning. R. ornithinolytica is a histamine-producing bacterium recently elucidated as a major cause of histamine fish poisoning. Only 2 other cases of human infection by R. ornithinolytica have been reported.
Hadano, Yoshiro; Tsukahara, Mika; Ito, Kenta; Suzuki, Jun; Kawamura, Ichiro; Kurai, Hanako
Raoultella ornithinolytica is a Gram-negative aerobic bacillus reclassified in the new genus from the Klebsiella species based on new genetic approaches; however, human infections caused by R. ornithinolytica are rare. We herein report three cases of R. ornithinolytica bacteremia associated with biliary tract infections in cancer patients. R. ornithinolytica can be a causative pathogen of biliary tract infection in cancer patients.
Gaudreau, C; Delage, G; Rousseau, D; Cantor, E D
A review of the hospital records of 71 patients from whose blood viridans streptococci were isolated showed that in 13 cases the patient's illness was definitely related to the bacteremia: 4 patients had endocarditis, 3 had pneumonia, 2 had peritonitis and 1 each had meningitis, a scalp wound infection, sinusitis and otitis media. The bacteremia may have contributed to the two deaths among these 13 patients. In 45 cases the viridans streptococci may have contributed to the patient's illness: 15 patients had an infection of the lower respiratory tract and 7 an infection of the upper respiratory tract, 8 were neonates with suspected septicemia, 3 had soft tissue infections, 3 had leukemia and sepsis, and 9 had miscellaneous infections; the bacteremia was unrelated to the two deaths in this group. In another 13 cases the viridans streptococci could not be related to the patient's illness. The species most frequently isolated were Streptococcus mitis, S. sanguis II and S. MG-intermedius. The outcome of the bacteremia was generally good, even among the 11 patients not treated with antibiotics. When viridans streptococci are cultured from a single blood sample, further samples of blood and, if feasible, specimens from the associated focus of infection should be obtained for culture; further blood cultures are especially important in cases of suspected endocarditis.
Southern, P M; Kutscher, A E
We report two cases of bacteremia due to Neisseria cinerea. One was a 2.5-yr-old boy with otitis media and pneumonia, who responded to treatment with amoxicillin. The other was a 47-yr-old man with underlying ethanol abuse who developed severe polymicrobial sepsis due to apparent intraabdominal disease. This man died despite extensive antimicrobial therapy.
Full Text Available Patients with inflammatory bowel disease (IBD are a high risk population for bacteremia. Derangement in the mucosal architecture of the gastrointestinal (GI tract and frequent endoscopic interventions in immunocompromised individuals are considered primary causes. Isolation of opportunistic microorganisms from the bloodstream of IBD patients has been increasingly reported in recent years. Leclercia adecarboxylata is a ubiquitous, aerobic, motile, gram-negative bacillus. The human GI tract is known to harbor this rarely pathogenic microorganism. There are only a few case reports of bacteremia with this microorganism; the majority are either polymicrobial or associated with immunocompromised patients. We describe a case of monomicrobial L. adecarboxylata bacteremia in a 43-year-old female who presented with bloody diarrhea. Colonoscopy revealed diffuse colonic mucosal inflammation with numerous ulcers, and histopathology revealed crypt abscesses. Following an episode of rectal bleeding, two sets of blood cultures grew L. adecarboxylata, which was treated with intravenous ceftriaxone. After a complicated hospital course, she was eventually diagnosed with ulcerative colitis and enteropathic arthritis, treated with intravenous methylprednisolone, mesalamine, and infliximab which resulted in resolution of her symptoms. In our previously immunocompetent patient, derangement of the gut mucosal barrier was the likely cause of bacteremia, yet performing endoscopic intervention may have contributed to bacterial translocation.
Full Text Available Abstract Background Brucellosis may cause serious infections in healthy individuals living in countries that are endemic for the infection. However, reports of brucella infections in immunocompromised hosts are relatively rare. Case Presentations Reported here are two patients with acute leukemia who developed Brucella melitensis bacteremia during their follow up at the Armed Forces Hospital in Riyadh. The first patient developed B. melitensis bacteremia during the transformation of his myelodysplasia into acute myeloid leukemia. The second patient developed B. melitensis bacteremia while his acute lymphoblastic leukemia was under control. Interestingly, he presented with acute cholecystitis during the brucella sepsis. Both brucella infections were associated with a marked reduction in the hematological parameters in addition to other complications. The bacteremic episodes were successfully treated with netilmicin, doxycycline and ciprofloxacin. Conclusion Brucellosis can cause systemic infections, complicated bacteremia and serious morbidity in patients with acute leukemia living in endemic areas. These infections may occur at the presentation of the leukemia or even when the leukemia is in remission. Nevertheless, the early diagnosis of brucellosis and the administration of appropriate antimicrobial therapy for sufficient duration usually improves the outcome in these immunocompromised patients.
Juliana Pena Porto
Full Text Available Introduction Methicillin-resistant Staphylococcus aureus (MRSA is among the most important pathogens of nosocomial infections, mainly in intensive care units (ICUs, and accounts for 40-60% of all healthcare-associated S. aureus infections. We evaluated the incidence of nosocomial infection by S. aureus, identified the risk factors for MRSA infection, and evaluated the effect of resistance to methicillin on mortality in patients. Methods We conducted MRSA surveillance at a university hospital in Brazil from January 1, 2010, to December 31, 2010, and performed a retrospective case-control matched study to evaluate the frequency of subsequent MRSA bacteremia and death among patients. We evaluated and compared the risk factors between patients with MRSA and methicillin-sensitive Staphylococcus aureus (MSSA infection. Results Sepsis was the most common cause of infection (17.7/1,000 patient-days, followed by surgical site (11.4/1,000 patient-days, pneumonia (4.1/1,000 patient-days, and urinary tract infection (2.4/1,000 patient-days. The significant risk factors were time of hospitalization, use of central vascular catheter (CVC, urinary catheter, nasogastric tube, parenteral nutrition, tracheostomy, mechanical ventilation, and previous antibiotic administration, the latter of which was the only independent risk factor for MRSA infection. Mortality was significantly higher in patients with MRSA. The number of antibiotics tested was not related to increases in the frequency of MRSA/1,000 patient-days. The incidence of mortality attributable to MRSA (bloodstream infection BSI was 50%. Conclusions Surveillance results showed that the use of high levels of antibiotics was directly related to the development of MRSA infection, and the mortality attributable to MRSA in patients with bacteremia was significant.
Cárdenas, Ana María; Andreacchio, Kathleen A; Edelstein, Paul H
Mixed-population (heterogeneous) enterococcal bacteremia (MEB) is rarely reported. Based on one occasion in which Vitek2 missed a vancomycin-resistant subpopulation isolated from a patient, we developed a simple method to detect this subpopulation and determined MEB frequency. The four patients presented here had either Enterococcus faecium or Enterococcus faecalis bacteremia caused by both vancomycin-resistant enterococci (VRE) and vancomycin-susceptible enterococci (VSE). No prior common antibiotic therapy was observed, and bacteremia resolved with daptomycin, gentamicin, and/or linezolid treatment. In two cases, VRE presence was missed by Vitek2. To detect the VRE subpopulation, tryptic soy broth was inoculated from positive blood cultures and a saline suspension was inoculated to a vancomycin (6-μg/ml) (V6) plate. Two isolates from each patient were studied further. Relatedness was assessed by multilocus sequence typing, fitness was evaluated by growth curve and competition assays, and vanA presence was determined by PCR. MEB represented ∼5% of all enterococcal bacteremias. All VRE subpopulations grew on V6 plates but were missed in two instances by Vitek2. VRE and VSE isolates from each patient were closely related and did not differ in overall fitness. All four VRE isolates and 2/4 VSE isolates were vanA positive. MEBs occur regardless of prior antimicrobial therapy, are relatively common in our hospital, and are important to detect. As far as we know, this study is the first to report heterogeneous E. faecalis bacteremia. There is a simple method to detect VRE subpopulations that may be missed by Vitek2.
Lin, T-Y; Chan, M-C; Yang, Y-S; Lee, Y; Yeh, K-M; Lin, J-C; Chang, F-Y
Although Morganella morganii causes a variety of clinical infections, there are limited studies on M. morganii bacteremia after the year 2000. A total of 109 patients with M. morganii bacteremia at a medical center in Taiwan from 2003 to 2012 were studied. Among them, 30.3 % had polymicrobial bacteremia and 75.2 % had community-acquired infection. The most common underlying diseases were hypertension (62.4 %) and diabetes mellitus (38.5 %). The urinary tract (41.3 %) was the major portal of entry, followed by the hepatobiliary tract (27.5 %), skin and soft tissue (21.1 %), and primary bacteremia (10.1 %). Susceptibility testing of M. morganii isolates showed ubiquitous resistance to first-generation cephalosporins and ampicillin-clavulanate; resistance rates to gentamicin, piperacillin-tazobactam, and ciprofloxacin were 30.3 %, 1.8 %, and 10.1 %, respectively. Overall, the 14-day mortality was 14.7 %. Univariate analysis revealed that elevated blood urea nitrogen (BUN) values [p = 0.0137, odds ratio (OR) 5.26], intensive care unit (ICU) admission (p = 0.011, OR 4.4), and higher Acute Physiology and Chronic Health Evaluation II (APACHE II) scores (p < 0.001, OR 1.62) were significantly associated with mortality. The APACHE II score remained the only significant risk factor for mortality in multivariate analysis (p = 0.0012, OR 1.55). In conclusion, M. morganii bacteremia patients were mostly elderly, with one or more comorbidities. Most of the patients had community-acquired infection via the urinary and hepatobiliary tracts. Furthermore, prognosis can be predicted according to disease severity measured by the APACHE II score.
WU Xiao-xia; WAN Qi-quan; YE Qi-fa; ZHOU Jian-dang
Background Bacteremia remains a significant cause of morbidity and mortality after kidney transplantation.This study was conducted to investigate whether the polymorphisms of tumor necrosis factor (TNF)-β,interleukin (IL)-1β,and IL-1 receptor antagonist (IL-1ra) gene predicted the susceptibility to bacteremia within the first 6 months after kidney transplantation.Methods Subjects comprised 82 infected kidney transplant recipients and 60 non-infected kidney transplant recipients.Bacteremia was diagnosed in 16 of the 82 infected recipients.Genomic DNA from these 142 kidney transplant recipients was extracted from peripheral blood leukocytes.Regions containing the Ncol polymorphic site at position +252 of TNF-βgene and the Aval polymorphic site at position-511 of IL-1β gene were amplified by polymerase chain reaction (PCR) and subsequently digested with Ncol and Aval restriction enzymes,respectively.The polymorphic regions within intron 2 of IL-1ra gene containing variable numbers of a tandem repeat (VNTR) of 86 base pairs were amplified by PCR.Results Genotypic and allelic frequencies were similar between infected recipients and non-infected ones.Individual locus analysis showed that recipient TNF-β and IL-1ra gene polymorphisms were not associated with the presence of bacteremia (P=0.684 and P=0.567,respectively).However,genotype analysis revealed that recipient IL-1β-511CC genotype was strongly associated with susceptibility to develop bacteremia (P=0.003).Recipient IL-1β-511CC genotype (odds ratio 5.242,95％ confidence intervals 1.645-16.706,P=0.005) independently predicted the risk for bacteremia within the first 6 months after kidney transplantation.Conclusions These findings indicate a critical role of IL-1β gene polymorphisms in susceptibility to bacteremia after kidney transplantation,which may be useful to screen for patients at higher risk for post-transplant bacteremias.Thus,the identified individuals can benefit from preventive treatment and a
Juan S. Lasa
Full Text Available La celulitis es una inflamación aguda de la dermis y tejido celular subcutáneo de causa bacteriana, que generalmente complica a heridas, úlceras y dermatosis, aunque de manera frecuente no existe sitio de entrada. Se recomienda la realización de cultivo de punción de piel y partes blandas (PPB. Los hemocultivos raramente dan resultados positivos. El objetivo de este trabajo fue determinar la prevalencia de bacteriemia en pacientes internados en nuestra institución con diagnóstico de celulitis. Se analizaron retrospectivamente los registros clínicos de los pacientes con este diagnóstico al ingreso entre junio de 2007 y marzo de 2010. Se evaluaron los datos poblacionales, presencia de comorbilidades, y resultados de los cultivos. En ese período, se internaron 140 pacientes con diagnóstico de celulitis y a todos ellos se les realizó hemocultivo y cultivos de PPB. Setenta y cuatro eran varones (52.8%. La edad promedio: 47.5 ± 19.7 años (rango 16-94. El 40% tuvo cultivos positivos de PPB, en los que el Staphylococcus aureus meticilino resistente (SAMR fue el germen más frecuentemente aislado (35.7%; la prevalencia de bacteriemia fue del 8.6%, en donde el germen más frecuente fue Streptoccocus Beta hemolítico, grupo G (33% del total de hemocultivos positivos. La bacteriemia se asoció significativamente a mayor estadía hospitalaria (10.5 ± 8.9 vs. 4.9 ± 6, p = 0.004. Se asoció con mayor riesgo de hemocultivo positivo a ser diabético, tener cultivo de PPB positivo, consumo de alcohol y/o enfermedad pulmonar obstructiva crónica.Cellulitis is an acute inflammation of dermis and subcutaneous tissue, usually complicating wounds, ulcers, or dermatosis. Even though in these cases it is recommended to perform culture from skin and soft tissue samples, the utility of blood cultures remains controversial due to the low frequency of positive results. Here we report the prevalence of bacteremia in patients with cellulitis admitted in our
MF59- and Al(OH3-adjuvanted Staphylococcus aureus (4C-Staph vaccines induce sustained protective humoral and cellular immune responses, with a critical role for effector CD4 T cells at low antibody titers.
Full Text Available Staphylococcus aureus (S. aureus is an important opportunistic pathogen that may cause invasive life-threatening infections like sepsis and pneumonia. Due to increasing antibiotic-resistance, the development of an effective vaccine against S. aureus is needed. Although a correlate of protection against staphylococcal diseases is not yet established, several findings suggest that both antibodies and CD4 T cells might contribute to optimal immunity. In this study, we show that adjuvanting a multivalent vaccine (4C-Staph with MF59, an oil-in-water emulsion licensed in human vaccines, further potentiated antigen-specific IgG titers and CD4 T cell responses compared to alum and conferred protection in the peritonitis model of S. aureus infection. Moreover, we showed that MF59- and alum-adjuvanted 4C-Staph vaccines induced persistent antigen-specific humoral and T cell responses, and protected mice from infection up to 4 months after immunization. Furthermore, 4C-Staph formulated with MF59 was used to investigate which immune compartment is involved in vaccine-induced protection. Using CD4 T cell-depleted mice or B cell deficient mice, we demonstrated that both T and B cell responses contributed to 4C-Staph vaccine-mediated protective immunity. However, the role of CD4 T cells seemed more evident in the presence of low antibody responses. This study provides preclinical data further supporting the use of the adjuvanted 4C-Staph vaccines against S. aureus diseases, and provides critical insights on the correlates of protective immunity necessary to combat this pathogen.
Nielsen, Stig Lønberg; Lassen, Annmarie Touborg; Kolmos, Hans Jørn;
BACKGROUND: We investigated the overall and daily incidence of bacteremia among hospitalized patients and evaluated the traditional classification of bacteremia (community-onset vs nosocomial based on a 48-hour time window) by means of the daily incidence and associated 30-day mortality. METHODS...
Gao, Xue-jiao; Wang, Tian-cheng; Zhang, Ze-cai; Cao, Yong-guo; Zhang, Nai-sheng; Guo, Meng-yao
Mastitis, which commonly occurs during the postpartum period, is caused by the infection of the mammary glands. The most common infectious bacterial pathogen of mastitis is Staphylococcus aureus (S. aureus) in both human and animals. Brazilin, a compound isolated from the traditional herbal medicine Caesalpinia sappan L., has been shown to exhibit multiple biological properties. The present study was performed to determine the effect of brazilin on the inflammatory response in the mouse model of S. aureus mastitis and to confirm the mechanism of action involved. Brazilin treatment was applied in both a mouse model and cells. After brazilin treatment of cells, Western blotting and qPCR were performed to detect the protein levels and mRNA levels, respectively. Brazilin treatment significantly attenuated inflammatory cell infiltration and inhibited the expressions of TNF-α, IL-1β and IL-6 in a dose-dependent manner. Administration of brazilin in mice suppressed S. aureus-induced inflammatory injury and the production of proinflammatory mediators. This suppression was achieved by reducing the increased expression of TLR2 and regulating the NF-κB and MAPK signaling pathways in the mammary gland tissues and cells with S. aureus-induced mastitis. These results suggest that brazilin appears to be an effective drug for the treatment of mastitis and may be applied as a clinical therapy.
Fadi Al Akhrass
Full Text Available Rhodococcus is an emerging cause of opportunistic infection in immunocompromised patients, most commonly causing cavitary pneumonia. It has rarely been reported as a cause of isolated bacteremia. However, the relationship between bacteremia and central venous catheter is unknown. Between 2002 and 2010, the characteristics and outcomes of seventeen cancer patients with Rhodococcus bacteremia and indwelling central venous catheters were evaluated. Rhodococcus bacteremias were for the most part (94% central line-associated bloodstream infection (CLABSI. Most of the bacteremia isolates were Rhodococcus equi (82%. Rhodococcus isolates formed heavy microbial biofilm on the surface of polyurethane catheters, which was reduced completely or partially by antimicrobial lock solution. All CLABSI patients had successful response to catheter removal and antimicrobial therapy. Rhodococcus species should be added to the list of biofilm forming organisms in immunocompromised hosts and most of the Rhodococcus bacteremias in cancer patients are central line associated.
Aung, Kyaw Min; Sjöström, Annika E; von Pawel-Rammingen, Ulrich; Riesbeck, Kristian; Uhlin, Bernt Eric; Wai, Sun Nyunt
Cholera epidemics are caused by Vibrio cholerae serogroups O1 and O139, whereas strains collectively known as non-O1/non-O139 V. cholerae are found in cases of extraintestinal infections and bacteremia. The mechanisms and factors influencing the occurrence of bacteremia and survival of V. cholerae in normal human serum have remained unclear. We found that naturally occurring IgG recognizing V. cholerae outer membrane protein U (OmpU) mediates a serum-killing effect in a complement C1q-dependent manner. Moreover, outer membrane vesicles (OMVs) containing OmpU caused enhanced survival of highly serum-sensitive classical V. cholerae in a dose-dependent manner. OMVs from wild-type and ompU mutant V. cholerae thereby provided a novel means to verify by extracellular transcomplementation the involvement of OmpU. Our data conclusively indicate that loss, or reduced expression, of OmpU imparts resistance to V. cholerae towards serum killing. We propose that the difference in OmpU protein levels is a plausible reason for differences in serum resistance and the ability to cause bacteremia observed among V. cholerae biotypes. Our findings provide a new perspective on how naturally occurring antibodies, perhaps induced by members of the microbiome, may play a role in the recognition of pathogens and the provocation of innate immune defense against bacteremia.
Lau, Susanna K. P.; Chow, Wang-Ngai; Foo, Chuen-Hing; Curreem, Shirly O. T.; Lo, George Chi-Shing; Teng, Jade L. L.; Chen, Jonathan H. K.; Ng, Ricky H. Y.; Wu, Alan K. L.; Cheung, Ingrid Y. Y.; Chau, Sandy K. Y.; Lung, David C.; Lee, Rodney A.; Tse, Cindy W. S.; Fung, Kitty S. C.; Que, Tak-Lun; Woo, Patrick C. Y.
Unlike Elizabethkingia meningoseptica, the clinical importance of E. anophelis is poorly understood. We determined the clinical and molecular epidemiology of bacteremia caused by Elizabethkingia-like species from five regional hospitals in Hong Kong. Among 45 episodes of Elizabethkingia-like bacteremia, 21 were caused by Elizabethkingia, including 17 E. anophelis, three E. meningoseptica and one E. miricola; while 24 were caused by other diverse genera/species, as determined by 16S rRNA gene sequencing. Of the 17 cases of E. anophelis bacteremia, 15 (88%) were clinically significant. The most common diagnosis was pneumonia (n = 5), followed by catheter-related bacteremia (n = 4), neonatal meningitis (n = 3), nosocomial bacteremia (n = 2) and neutropenic fever (n = 1). E. anophelis bacteremia was commonly associated with complications and carried 23.5% mortality. In contrast, of the 24 episodes of bacteremia due to non-Elizabethkingia species, 16 (67%) were clinically insignificant. Compared to non-Elizabethkingia bacteremia, Elizabethkingia bacteremia was associated with more clinically significant infections (P < 0.01) and positive cultures from other sites (P < 0.01), less polymicrobial bacteremia (P < 0.01), and higher complication (P < 0.05) and mortality (P < 0.05) rates. Elizabethkingia bacteremia is predominantly caused by E. anophelis instead of E. meningoseptica. Elizabethkingia bacteremia, especially due to E. anophelis, carries significant morbidity and mortality, and should be considered clinically significant unless proven otherwise. PMID:27185741
Hur, Jaehyung; Lee, Anna; Hong, Jeongmin; Jo, Won-yong; Cho, Oh-Hyun; Kim, Sunjoo; Bae, In-Gyu
Staphylococcus saprophyticus is a common pathogen of acute urinary tract infection (UTI) in young females. However, S. saprophyticus bacteremia originating from UTI is very rare and has not been reported in Korea. We report a case of S. saprophyticus bacteremia from UTI in a 60-year-old female with a urinary stone treated successfully with intravenous ciprofloxacin, and review the cases of S. saprophyticus bacteremia reported in the literature. Thus, the microorganism may cause invasive infec...
Garnacho-Montero, José; Amaya-Villar, Rosario; Ferrándiz-Millón, Carmen; Díaz-Martín, Ana; López-Sánchez, José María; Gutiérrez-Pizarraya, Antonio
Carbapenem-resistant Acinetobacter baumannii (CRAB) constitutes an increasing problem worldwide. CRAB bacteremia is associated with a high fatality rate and its optimal treatment has not been established. Early institution of appropriate therapy is shown to improve survival of patients with CRAB bloodstream infection. Regrettably, treatment options are limited. Little information exists about the efficacy of sulbactam for the treatment of CRAB bacteremia. Colistin and tigecycline possess good in vitro activity and represent in many cases the only therapeutic options although clinical data are scarce. The need for a loading dose of colistin has been recently demonstrated to rapidly achieve therapeutic levels. The use of combination therapy is also a matter of debate but current evidence do not support its routine use.
Demiray, Tayfur; Aydemir, Ozlem Akkaya; Koroglu, Mehmet; Ozbek, Ahmet; Altindis, Mustafa
Morganella morganii is rarely isolated from nosocomial infections. However, postoperative infections due to Morganella spp. were documented in literature and eye involvements of the infections usually result in severe sequels. We present a severe case infection, which was caused by M. morganii subsp. morganii, firstly appearing as conjunctivitis and complicated by bacteremia. The infectious agent isolated from both conjunctival and consecutive blood cultures. Identification and antimicrobial susceptibility tests were performed with the Vitek 2(®) automated system. The isolate was resistant to cephalosporins and carbapenems and it had ability to produce extended spectrum beta-lactamases. Patient was successfully treated with intravenous ciprofloxacin according to susceptibility test results. This is the first report of M. morganii infection detected as a local infection then complicated by bacteremia.
Carroll, W L; Farrell, M K; Singer, J I; Jackson, M A; Lobel, J S; Lewis, E D
Antibiotic therapy for children without foci of infection and at risk for bacteremia is controversial. A prospective randomized clinical trial was conducted using expectant antibiotic therapy in children at risk for bacteremia. A total of 96 children (aged 6 to 24 months) with temperature of more than 40 degrees C, no identifiable source of infection, and a leukocyte count greater than or equal to 15,000/microL and/or sedimentation rate greater than or equal to 30 were enrolled. The following tests were performed on all children: blood culture, chest roentgenogram, urinalysis, and urine culture. A lumbar puncture was performed if a child was 12 months or less. Patients were randomized to receive either no antibiotic therapy or Bicillin C-R, 50,000 U/kg intramuscularly, followed by penicillin V, 100 mg/kg/d, orally four times a day for three days. Patients were examined at 24 and 72 hours. Fifty patients were treated expectantly and 46 received no antimicrobial therapy. Ten of the 96 patients were bacteremic (nine had Streptococcus pneumoniae, one had Haemophilus influenzae). Four of the five children treated for bacteremia showed improvement at the first follow-up visit (afebrile and no obvious focus of infection). The five untreated patients showed no improvement; four patients developed focal infections (two had meningitis, two had otitis media) (P less than or equal to .05, Fisher exact test). No complications of expectant therapy were detected. Thus, expectant antibiotic therapy for children who have no obvious source of infection and who meet these criteria associated with occult bacteremia is warranted.
Kim, Sun Bean; Jeon, Yong Duk; Kim, Jung Ho; Kim, Jae Kyoung; Ann, Hea Won; Choi, Heun; Kim, Min Hyung; Song, Je Eun; Ahn, Jin Young; Jeong, Su Jin; Han, Sang Hoon; Choi, Jun Yong; Song, Young Goo; Kim, June Myung
Purpose Over the last 30 years, Serratia marcescens (S. marcescens) has emerged as an important pathogen, and a common cause of nosocomial infections. The aim of this study was to identify risk factors associated with mortality in patients with S. marcescens bacteremia. Materials and Methods We performed a retrospective cohort study of 98 patients who had one or more blood cultures positive for S. marcescens between January 2006 and December 2012 in a tertiary care hospital in Seoul, South Korea. Multiple risk factors were compared with association with 28-day all-cause mortality. Results The 28-day mortality was 22.4% (22/98 episodes). In a univariate analysis, the onset of bacteremia during the intensive care unit stay (p=0.020), serum albumin level (p=0.011), serum C-reactive protein level (p=0.041), presence of indwelling urinary catheter (p=0.023), and Sequential Oran Failure Assessment (SOFA) score at the onset of bacteremia (p<0.001) were significantly different between patients in the fatal and non-fatal groups. In a multivariate analysis, lower serum albumin level and an elevated SOFA score were independently associated with 28-day mortality [adjusted odds ratio (OR) 0.206, 95% confidential interval (CI) 0.044-0.960, p=0.040, and adjusted OR 1.474, 95% CI 1.200-1.810, p<0.001, respectively]. Conclusion Lower serum albumin level and an elevated SOFA score were significantly associated with adverse outcomes in patients with S. marcescens bacteremia. PMID:25683980
Khatib, R; Labalo, V; Sharma, M; Johnson, L B; Riederer, K
We retrospectively evaluated adult cases with Enterococcus spp. in 1 blood culture (BC) (1/1/2010-12/31/2015; n=294) and stratified them into bacteremia or contamination. Contamination frequency was similar in community versus hospital-onset, E. faecalis versus E. faecium, and number of BC drawn per day. Contamination predictors were vancomycin-resistance, ampicillin-resistance, commensal organism copresence, and nonurinary/abdominal sources.
Tejera, Darwin; Limongi, Gino; Bertullo, Mauricio; Cancela, Mario
Ralstonia pickettii is a low-virulence gram-negative bacillus that may be associated with infections related to health care and may cause bacteremia. Ralstonia pickettii bacteremia is uncommon but is related to the contamination of medical products, mainly in immunodepressed patients. We present two cases of patients on chronic hemodialysis with Ralstonia pickettii bacteremia linked to contamination of the dialysis water. Similar cases have been published with links to intravenous fluid administration, medication ampules, and the use of extracorporeal oxygenation membranes, among other factors. The detection of Ralstonia pickettii bacteremia should provoke suspicion and a search for contaminated medical products, fluids, and/or medications. PMID:27410414
谭小蓉; 刘玉; 牟春花; 高亚萍; 董洁; 杨光
Objective To investigate the regulatory function of Staphylococcus aureus accessory regulator S (SarS) protein in 5. aureus via insertion mutant construction. Methods The sarS inactive mutant was constructed by homologous re -combination in 5. aureus 8325 -4. The level of extra-toxins production was detected in MDBK cells , and the growth curves under different stress conditions were measured . Results The sarS mutant was successfully constructed in 5. aureus 8325 -4. Compared with its parent strain , the level of extra-toxins and the growth of the sarS mutant were not altered. However, it was found that the growth rate of sarS mutant was significantly decreased under several stress conditions compared with its parent strain. Conclusion SarS plays an important role in stress responses in 5. aureus.%目的 通过构建金黄色葡萄球菌(Staphylococcus aureus,简称金葡菌)中SarS蛋白突变株,研究SarS蛋白在金葡菌中的调控功能.方法 利用同源重组的方法构建金葡菌8325-4来源的sarS插入突变菌株,通过MDBK细胞模型检测突变株外毒素水平,以及其在高盐、高温等条件下的生长情况.结果 成功构建了金葡菌8325-4来源的sarS插入突变菌株.进一步的表型检测结果显示,与野生型菌株相比,sarS突变株在高温、高渗、重金属等应激条件下的生长速度明显下降,但是细菌外毒素对MDBK细胞的杀伤作用没有明显的改变.结论 SarS蛋白在金葡菌抵抗外界压力应激中发挥着重要的功能.
Chen, Zhong; Pan, Wei-Guang; Xian, Wei-Yi; Cheng, Hang; Zheng, Jin-Xin; Hu, Qing-Hua; Yu, Zhi-Jian; Deng, Qi-Wen
Staphylococcus aureus is a well-known organism which is responsible for a variety of human infectious diseases including skin infections, pneumonia, bacteremia, and endocarditis. Few of the microorganisms can be transmitted from mother to the newborn or infant by milk breastfeeding. This study aims to identify transmission of S. aureus from healthy, lactating mothers to their infants by breastfeeding. Stool specimens of diarrheal infants and breast milk of their mother (totally three pairs) were collected and six Staphylococcus aureus isolates were cultured positively. Homology and molecular characters of isolated strains were tested using pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing. Furthermore, toxin genes detection was also performed. Each pair of isolates has the same PFGE type and spa type. Four Sequence types (STs) were found among all the isolates; they are ST15, ST188, and ST59, respectively. Among the strains, seb, sec, and tst genes were found, and all were negative for pvl gene. The homology of the S. aureus strains isolated from the infants' stool and the mothers' milk was genetically demonstrated, which indicated that breastfeeding may be important in the transmission of S. aureus infection, and the character of S. aureus needed to be further evaluated.
Viedma, Esther; Chaves, Fernando; Lalueza, Antonio; Fortún, Jesús; Loza, Elena; Pujol, Miquel; Ardanuy, Carmen; Morales, Isabel; de Cueto, Marina; Resino-Foz, Elena; Morales-Cartagena, Alejandra; Rico, Alicia; Romero, María P.; Orellana, María Ángeles; López-Medrano, Francisco; Fernández-Ruiz, Mario; Aguado, José María
We investigated the prognostic role of high MICs for antistaphylococcal agents in patients with methicillin-sensitive Staphylococcus aureus catheter-related bloodstream infection (MSSA CRBSI). We prospectively reviewed 83 episodes from 5 centers in Spain during April 2011–June 2014 that had optimized clinical management and analyzed the relationship between E-test MICs for vancomycin, daptomycin, oxacillin, and linezolid and development of complicated bacteremia by using multivariate analysis. Complicated MSSA CRBSI occurred in 26 (31.3%) patients; MICs for vancomycin and daptomycin were higher in these patients (optimal cutoff values for predictive accuracy = 1.5 μg/mL and 0.5 μg/mL). High MICs for vancomycin (hazard ratio 2.4, 95% CI 1.2–5.5) and daptomycin (hazard ratio 2.4, 95% CI 1.1–5.9) were independent risk factors for development of complicated MSSA CRBSI. Our data suggest that patients with MSSA CRBSI caused by strains that have high MICs for vancomycin or daptomycin are at increased risk for complications. PMID:27192097
Full Text Available Staphylococcus aureus encodes a remarkable number of virulence factors which may contribute to its pathogenicity and ability to cause invasive disease. The main objective of this study was to evaluate the association between S. aureus invasiveness and bacterial genotype, in terms of the presence of virulence genes and affiliation to clonal complexes. Also, the significance of different virulence genes, mainly adhesins, for the development of infective endocarditis was investigated. DNA microarray technology was used to analyze 134 S. aureus isolates, all methicillin-susceptible, derived from three groups of clinically well-characterized patients: nasal carriers (n=46, bacteremia (n=55, and bacteremia with infective endocarditis (n=33. Invasive isolates were dominant in four of the major clonal complexes: 5, 8, 15, and 25. Of the 170 virulence genes examined, those encoding accessory gene regulator group II (agr II, capsule polysaccharide serotype 5 (cap5, and adhesins such as S. aureus surface protein G (sasG and fibronectin-binding protein B (fnbB were found to be associated with invasive disease. The same was shown for the leukocidin genes lukD/lukE, as well as the genes encoding serine protease A and B (splA/splB, staphylococcal complement inhibitor (scn and the staphylococcal exotoxin-like protein (setC or selX. In addition, there was a trend of higher prevalence of certain genes or gene clusters (sasG, agr II, cap5 among isolates causing infective endocarditis compared to other invasive isolates. In most cases, the presence of virulence genes was linked to clonal complex affiliation. In conclusion, certain S. aureus clonal lineages harboring specific sets of virulence genes seem to be more successful in causing invasive disease.
Perera, Varahenage R; Newton, Gerald L; Pogliano, Kit
Bacillithiol is a low-molecular-weight thiol analogous to glutathione and is found in several Firmicutes, including Staphylococcus aureus. Since its discovery in 2009, bacillithiol has been a topic of interest because it has been found to contribute to resistance during oxidative stress and detoxification of electrophiles, such as the antibiotic fosfomycin, in S. aureus. The rapid increase in resistance of methicillin-resistant Staphylococcus aureus (MRSA) to available therapeutic agents is a great health concern, and many research efforts are focused on identifying new drugs and targets to combat this organism. This review describes the discovery of bacillithiol, studies that have elucidated the physiological roles of this molecule in S. aureus and other Bacilli, and the contribution of bacillithiol to S. aureus fitness during pathogenesis. Additionally, the bacillithiol biosynthesis pathway is evaluated as a novel drug target that can be utilized in combination with existing therapies to treat S. aureus infections.
Pedersen, Michael; Brandt, Christian T.; Knudsen, Gitte Moos
In the present study, we studied the effect of bacteremia on cerebral blood flow (CBF) autoregulation in a rat model of pneumococcal bacteremia and meningitis. Anesthetized rats were divided into five groups (A to E) and inoculated with pneumococci intravenously and normal saline intracisternally...
Schaefer, Gabrielle; Campbell, Wesley; Jenks, Jeffrey; Beesley, Cari; Katsivas, Theodoros; Hoffmaster, Alex; Mehta, Sanjay R; Reed, Sharon
Bacillus cereus is typically considered a blood culture contaminant; however, its presence in blood cultures can indicate true bacteremia. We report 4 episodes of B. cereus bacteremia in 3 persons who inject drugs. Multilocus sequence typing showed that the temporally associated infections were caused by unrelated clones.
Schaefer, Gabrielle; Campbell, Wesley; Jenks, Jeffrey; Beesley, Cari; Katsivas, Theodoros; Hoffmaster, Alex; Mehta, Sanjay R.; Reed, Sharon
Bacillus cereus is typically considered a blood culture contaminant; however, its presence in blood cultures can indicate true bacteremia. We report 4 episodes of B. cereus bacteremia in 3 persons who inject drugs. Multilocus sequence typing showed that the temporally associated infections were caused by unrelated clones.
Ong, David S Y; Bonten, Marc J M; Safdari, Khatera; Spitoni, Cristian; Frencken, Jos F; Witteveen, Esther; Horn, Janneke; Klein Klouwenberg, Peter M C; Cremer, Olaf L
BACKGROUND: Enterococcal bacteremia has been associated with high case fatality, but it remains unknown to what extent death is caused by these infections. We therefore quantified attributable mortality of intensive care unit (ICU)-acquired bacteremia caused by enterococci. METHODS: From 2011 to 201
Ong, David S Y; Bonten, Marc J M; Safdari, Khatera; Spitoni, Cristian; Frencken, Jos F; Witteveen, Esther; Horn, Janneke; Klein Klouwenberg, Peter M C; Cremer, Olaf L
BACKGROUND: Enterococcal bacteremia has been associated with high case fatality, but it remains unknown to what extent death is caused by these infections. We therefore quantified attributable mortality of intensive care unit (ICU)-acquired bacteremia caused by enterococci. METHODS: From 2011 to 2
Hansen, S.L.; Hetmanski, J
Blood subcultures repeated 3 days after the cultures were first identified as positives increased our detection of polymicrobic bacteremia in 9.1 to 27% of clinically significant patient episodes. Reincubation and repeated subculture of previously positive blood cultures had a direct impact on the therapeutic management of patients with polymicrobic bacteremia.
Holler, Jon G; Brandt, Christian T; Leib, Stephen L;
pneumococci. The study comprised of four experimental groups. I. Uninfected controls (n = 8); II. Meningitis (n = 11); III. Meningitis with early onset bacteremia by additional i.v. injection of live pneumococci (n = 10); IV. Meningitis with attenuated bacteremia by treatment with serotype-specific anti...
Tugcu, Deniz; Turel, Ozden; Aydogan, Gonul; Akcay, Arzu; Salcioglu, Zafer; Akici, Ferhan; Sen, Hulya; Demirkaya, Metin; Taskin, Necati; Gurler, Nezahat
Achromobacter xylosoxidans is an aerobic gram-negative bacillus and important cause of bacteremia in immunocompromised patients. We describe a leukemia pediatric patient with severe neutropenia who developed bacteremia with A xylosoxidans resistant to multiple antibiotics, and treated the patient with tigecycline and piperacillin-tazobactam in addition to supportive medications.
Liu, Cindy M; Price, Lance B; Hungate, Bruce A
The human microbiome can play a key role in host susceptibility to pathogens, including in the nasal cavity, a site favored by Staphylococcus aureus. However, what determines our resident nasal microbiota-the host or the environment-and can interactions among nasal bacteria determine S. aureus...
Yoon, Young Kyung; Kim, Hyun Ah; Ryu, Seong Yeol; Lee, Eun Jung; Lee, Mi Suk; Kim, Jieun; Park, Seong Yeon; Yang, Kyung Sook; Kim, Shin Woo
This study aimed to construct a prediction algorithm, which is readily applicable in the clinical setting, to determine the mortality rate for patients with P. aeruginosa bacteremia. A multicenter observational cohort study was performed retrospectively in seven university-affiliated hospitals in Korea from March 2012 to February 2015. In total, 264 adult patients with monomicrobial P. aeruginosa bacteremia were included in the analyses. Among the predictors independently associated with 30-day mortality in the Cox regression model, Pitt bacteremia score >2 and high-risk source of bacteremia were identified as critical nodes in the tree-structured survival analysis. Particularly, the empirical combination therapy was not associated with any survival benefit in the Cox regression model compared to the empirical monotherapy. This study suggests that determining the infection source and evaluating the clinical severity are critical to predict the clinical outcome in patients with P. aeruginosa bacteremia.
Yoo, Jin-Hong; Lee, Dong-Gun; Choi, Su Mi; Choi, Jung-Hyun; Shin, Wan-Shik; Kim, Myungshin; Yong, Dongeun; Lee, Kyungwon; Min, Woo-Sung; Kim, Chun-Choo
An increase in vancomycin-resistant enterococcal (VRE) bacteremia in hemato-oncological patients (n=19) in our institution from 2000 through 2001 led us to analyze the molecular epidemiologic patterns and clinical features unique to our cases. The pulsed field gel electrophoresis of the isolates revealed that the bacteremia was not originated from a single clone but rather showed endemic pattern of diverse clones with small clusters. A different DNA pattern of blood and stool isolates from one patient suggested exogenous rather than endogenous route of infection. Enterococcus faecium carrying vanA gene was the causative pathogen in all cases. Patients with VRE bacteremia showed similar clinical courses compared with those with vancomycin-susceptible enterococcal (VSE) bacteremia. Vancomycin resistance did not seem to be a poor prognostic factor because of similar mortality (5/8, 62.5%) noted in VSE bacteremia. Initial disease severity and neutropenic status may be major determinants of prognosis in patients with VRE bacteraemia.
Full Text Available Staphylococcus aureus bacteraemia (SAB is commonly complicated by metastatic infection or relapse after treatment. Objectives. The study aim was to determine the role of bacterial, host, and management factors in development of complicated SAB. Methods. A prospectively-conducted observational study gathered data on predisposition, management and outcome of 100 consecutive SAB cases. Antibiotic susceptibilities and genetic lineage of bacterial isolates were determined. Further clinical and microbiological data were gathered on two retrospective series from 1999–2000 (n=57 and 2004 (n=116. Results. In the prospective cases, 27% met our definition of complicated disease. Expressed as RR and 95% CI, complicated disease was associated with diabetes (1.58, 1.00–2.48, injecting-drug use (5.48, 0.88–33.49, community-onset of symptoms (1.4, 1.02–1.92, and symptom duration ≥48 hours prior to starting effective antibiotic therapy (2.10, 1.22–3.61. Uncomplicated disease was associated with the presence of a central line (0.69, 0.55–0.88 and prompt removal of a primary focus (0.71, 0.57–0.90. Neither methicillin resistance nor genetic lineage was associated with complicated disease, but methicillin resistance was associated with higher mortality. Conclusions. This study demonstrates that clinical rather than microbial factors are the major determinants of SAB outcome and underscores the importance of early treatment.
Lee, Yangsoon; Park, Yongjung; Kim, Myungsook; Choi, Jun Yong; Yong, Dongeun; Jeong, Seok Hoon
Background Investigation on incidence and mortality of anaerobic bacteremia (AB) is clinically relevant in spite of its infrequent occurrence and not often explored, which report varies according to period and institutions. Therefore, it is necessary to analyze the incidence and risk factors related to mortality and assess clinical outcomes of AB in current aspect. Materials and Methods Characteristics of AB patients and anaerobic bacteria from blood culture at a university hospital in 2012 were reviewed retrospectively. The correlation between risk factors and 28-day patient mortality was analyzed. Results A total of 70 non-duplicated anaerobic bacteria were isolated from blood of 70 bacteremia patients in 2012. The history of cardiovascular disease as host's risk factor was statistically significant (P = 0.0344) in univariate and multivariate analysis. Although the inappropriate therapy was not statistically significant in univariate and multivariate analysis, the survival rate of bacteremia was significantly worse in patients who had inappropriate therapy compared with those underwent appropriate therapy (hazard ratio, 5.4; 95% confidence interval, 1.7–6.9; P = 0.004). The most frequently isolated organism was Bacteroides fragilis (32 isolates, 46%), followed by Bacteroides thetaiotaomicron (10, 14%), and non-perfringens Clostridium (7, 10%). Conclusion The incidence of AB in 2012 was 2.3% (number of AB patients per 100 positive blood culture patients) and the mortality rate in patients with clinically significant AB was 21.4%. In addition, AB was frequently noted in patients having malignancy and the survival rate of AB was significantly worse in patients who received inappropriate therapy compared with those underwent appropriate therapy. PMID:27433379
Chen, Chung-Hua; Lin, Jesun; Lin, Jen-Shiou; Chen, Yu-Min
We present the case of a 49-year-old man, who developed Mycobacterium abscessus complex (M. abscessus complex) bacteremia and prostatitis after prostate biopsy. The patient was successfully treated with amikacin with imipenem-cilastatin with clarithromycin. Infections caused by M. abscessus complex have been increasingly described as a complication associated with many invasive procedures. Invasive procedures might have contributed to the occurrence of the M. abscessus complex. Although M. abscessus complex infection is difficult to diagnose and treat, we should pay more attention to this kind of infection, and the correct treatment strategy will be achieved by physicians.
Full Text Available Desulfovibrio spp. are gram-negative, sulfate-reducing, and anaerobic bacteria found in the digestive tract of humans. Because Desulfovibrio spp. are infrequent causative agents of infectious diseases and are difficult to isolate and to identify from clinical specimens, the appropriate antibiotic therapy to infection with Desulfovibrio spp. has not been determined. We report the first case of liver abscess with bacteremia due to Desulfovibrio desulfuricans to show the clinical presentation and treatment. The patient was successfully treated with intravenous piperacillin-tazobactam and oral amoxicillin-clavulanic acid.
Knudtzen, Fredrikke Christie; Nielsen, Stig Lønberg; Gradel, Kim Oren;
To characterize patients presenting with community-acquired bacteremia and a low C-reactive protein (CRP) plasma level at date of bacteremia.......To characterize patients presenting with community-acquired bacteremia and a low C-reactive protein (CRP) plasma level at date of bacteremia....
Parlet, Corey P.; Kavanaugh, Jeffrey S.; Horswill, Alexander R.; Schlueter, Annette J.
Alcoholics are at increased risk of Staphylococcus aureus skin infection and serious sequelae, such as bacteremia and death. Despite the association between alcoholism and severe S. aureus skin infection, the impact of EtOH on anti-S. aureus cutaneous immunity has not been investigated in a model of chronic EtOH exposure. To test the hypothesis that EtOH enhances the severity of S. aureus skin infection, mice were fed EtOH for ≥12 weeks via the Meadows-Cook model of alcoholism and inoculated with S. aureus following epidermal abrasion. Evidence of exacerbated staphylococcal disease in EtOH-fed mice included: skin lesions that were larger and contained more organisms, greater weight loss, and increased bacterial dissemination. Infected EtOH-fed mice demonstrated poor maintenance and induction of PMN responses in skin and draining LNs, respectively. Additionally, altered PMN dynamics in the skin of these mice corresponded with reduced production of IL-23 and IL-1β by CD11b+ myeloid cells and IL-17 production by γδ T cells, with the latter defect occurring in the draining LNs as well. In addition, IL-17 restoration attenuated S. aureus-induced dermatopathology and improved bacterial clearance defects in EtOH-fed mice. Taken together, the findings show, in a novel model system, that the EtOH-induced increase in S. aureus-related injury/illness corresponds with defects in the IL-23/IL-17 inflammatory axis and poor PMN accumulation at the site of infection and draining LNs. These findings offer new information about the impact of EtOH on cutaneous host-defense pathways and provide a potential mechanism explaining why alcoholics are predisposed to S. aureus skin infection. PMID:25605871
Matsuda, Mari; Iguchi, Shigekazu; Mizutani, Tomonori; Hiramatsu, Keiichi; Tega-Ishii, Michiru; Sansaka, Kaori; Negishi, Kenta; Shimada, Kimie; Umemura, Jun; Notake, Shigeyuki; Yanagisawa, Hideji; Yabusaki, Reiko; Araoka, Hideki; Yoneyama, Akiko
Background. Early detection of Gram-positive bacteremia and timely appropriate antimicrobial therapy are required for decreasing patient mortality. The purpose of our study was to evaluate the performance of the Verigene Gram-positive blood culture assay (BC-GP) in two special healthcare settings and determine the potential impact of rapid blood culture testing for Gram-positive bacteremia within the Japanese healthcare delivery system. Furthermore, the study included simulated blood cultures, which included a library of well-characterized methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) isolates reflecting different geographical regions in Japan. Methods. A total 347 BC-GP assays were performed on clinical and simulated blood cultures. BC-GP results were compared to results obtained by reference methods for genus/species identification and detection of resistance genes using molecular and MALDI-TOF MS methodologies. Results. For identification and detection of resistance genes at two clinical sites and simulated blood cultures, overall concordance of BC-GP with reference methods was 327/347 (94%). The time for identification and antimicrobial resistance detection by BC-GP was significantly shorter compared to routine testing especially at the cardiology hospital, which does not offer clinical microbiology services on weekends and holidays. Conclusion. BC-GP generated accurate identification and detection of resistance markers compared with routine laboratory methods for Gram-positive organisms in specialized clinical settings providing more rapid results than current routine testing.
Full Text Available Background. Early detection of Gram-positive bacteremia and timely appropriate antimicrobial therapy are required for decreasing patient mortality. The purpose of our study was to evaluate the performance of the Verigene Gram-positive blood culture assay (BC-GP in two special healthcare settings and determine the potential impact of rapid blood culture testing for Gram-positive bacteremia within the Japanese healthcare delivery system. Furthermore, the study included simulated blood cultures, which included a library of well-characterized methicillin-resistant Staphylococcus aureus (MRSA and vancomycin-resistant enterococci (VRE isolates reflecting different geographical regions in Japan. Methods. A total 347 BC-GP assays were performed on clinical and simulated blood cultures. BC-GP results were compared to results obtained by reference methods for genus/species identification and detection of resistance genes using molecular and MALDI-TOF MS methodologies. Results. For identification and detection of resistance genes at two clinical sites and simulated blood cultures, overall concordance of BC-GP with reference methods was 327/347 (94%. The time for identification and antimicrobial resistance detection by BC-GP was significantly shorter compared to routine testing especially at the cardiology hospital, which does not offer clinical microbiology services on weekends and holidays. Conclusion. BC-GP generated accurate identification and detection of resistance markers compared with routine laboratory methods for Gram-positive organisms in specialized clinical settings providing more rapid results than current routine testing.
Diego O Andrey
Full Text Available Staphylococcus aureus is an important pathogen manifesting virulence through diverse disease forms, ranging from acute skin infections to life-threatening bacteremia or systemic toxic shock syndromes. In the latter case, the prototypical superantigen is TSST-1 (Toxic Shock Syndrome Toxin 1, encoded by tst(H, and carried on a mobile genetic element that is not present in all S. aureus strains. Transcriptional regulation of tst is only partially understood. In this study, we dissected the role of sarA, sarS (sarH1, RNAIII, rot, and the alternative stress sigma factor sigB (σB. By examining tst promoter regulation predominantly in the context of its native sequence within the SaPI1 pathogenicity island of strain RN4282, we discovered that σB emerged as a particularly important tst regulator. We did not detect a consensus σB site within the tst promoter, and thus the effect of σB is likely indirect. We found that σB strongly repressed the expression of the toxin via at least two distinct regulatory pathways dependent upon sarA and agr. Furthermore rot, a member of SarA family, was shown to repress tst expression when overexpressed, although its deletion had no consistent measurable effect. We could not find any detectable effect of sarS, either by deletion or overexpression, suggesting that this regulator plays a minimal role in TSST-1 expression except when combined with disruption of sarA. Collectively, our results extend our understanding of complex multifactorial regulation of tst, revealing several layers of negative regulation. In addition to environmental stimuli thought to impact TSST-1 production, these findings support a model whereby sporadic mutation in a few key negative regulators can profoundly affect and enhance TSST-1 expression.
Andrey, Diego O; Jousselin, Ambre; Villanueva, Maite; Renzoni, Adriana; Monod, Antoinette; Barras, Christine; Rodriguez, Natalia; Kelley, William L
Staphylococcus aureus is an important pathogen manifesting virulence through diverse disease forms, ranging from acute skin infections to life-threatening bacteremia or systemic toxic shock syndromes. In the latter case, the prototypical superantigen is TSST-1 (Toxic Shock Syndrome Toxin 1), encoded by tst(H), and carried on a mobile genetic element that is not present in all S. aureus strains. Transcriptional regulation of tst is only partially understood. In this study, we dissected the role of sarA, sarS (sarH1), RNAIII, rot, and the alternative stress sigma factor sigB (σB). By examining tst promoter regulation predominantly in the context of its native sequence within the SaPI1 pathogenicity island of strain RN4282, we discovered that σB emerged as a particularly important tst regulator. We did not detect a consensus σB site within the tst promoter, and thus the effect of σB is likely indirect. We found that σB strongly repressed the expression of the toxin via at least two distinct regulatory pathways dependent upon sarA and agr. Furthermore rot, a member of SarA family, was shown to repress tst expression when overexpressed, although its deletion had no consistent measurable effect. We could not find any detectable effect of sarS, either by deletion or overexpression, suggesting that this regulator plays a minimal role in TSST-1 expression except when combined with disruption of sarA. Collectively, our results extend our understanding of complex multifactorial regulation of tst, revealing several layers of negative regulation. In addition to environmental stimuli thought to impact TSST-1 production, these findings support a model whereby sporadic mutation in a few key negative regulators can profoundly affect and enhance TSST-1 expression.
Olivi, M.; Alfè, M.; Gargiulo, V.; Valle, F.; Mura, F.; Di Giosia, M.; Rapino, S.; Palleschi, C.; Uccelletti, D.; Fiorito, S.
The exploitation of nanomaterials with antimicrobial properties has attracted an ever-growing interest in the recent years. Carbon-based materials, such as graphene and graphene family materials (GFMs), have gained most of the attention for application in many biomedical fields. Here, we describe the antimicrobial activity of graphene-like (GL) layers derived from the chemical demolition of carbon black, against the planktonic growth of Staphylococcus aureus cells, primary cause of hospital and community-acquired infections, often leading to bacteremia and sepsis. The inhibitory capabilities of GL layers on the formation of S. aureus biofilm are also assessed. The antimicrobial properties seem based mainly on the interaction between GL layers and bacteria surfaces. FESEM and AFM analyses suggest that the GL layers coat the cells as soon as they get in contact with them, as also indicated by the wettability of the GLs.
Walther Frans J
Full Text Available Abstract Background Coagulase negative staphylococci (CoNS are the most common cause of neonatal sepsis in the Neonatal Intensive Care Unit (NICU. A minority of neonates does not respond to vancomycin therapy and develops persistent bacteremia, which may be treated with rifampin. We evaluated the use of rifampin in persistent CoNS bacteremia. Methods Retrospective study of 137 neonates with CoNS bacteremia during admission to a tertiary NICU between July 2006 and July 2009. Main outcome measures were total duration of bacteremia and the adequacy of vancomycin and rifampin therapy. Results 137/1696 (8.0% neonates developed a CoNS bacteremia. Eighteen were treated with rifampin because of persistent bacteremia (3 positive blood cultures at least 48 hours apart with clinical symptoms or (a serious suspicion of an intravascular thrombus. Duration of bacteremia prior to rifampin therapy (8.0 ± 3.6 days was positively correlated (p Conclusion Rifampin may be effective in the treatment of persistent CoNS infections in neonates. Outcome may be improved by adequate monitoring of vancomycin trough levels.
Malachowa, Natalia; DeLeo, Frank R
Methicillin-resistant Staphylococcus aureus (MRSA) is abundant in hospitals and in the United States is a leading cause of mortality due to infectious agents. Community-associated MRSA (CA-MRSA) strains such as USA300, which typically cause disease outside of healthcare settings, are also prevalent in the United States. Although most CA-MRSA infections affect skin and soft tissue, the pathogen can enter the bloodstream and ultimately cause severe disease. In a recent paper, we used USA300-specific microarrays to generate a comprehensive view of the molecules that facilitate S. aureus immune evasion and survival in human blood. Notably, genes encoding proteins involved in iron-uptake and utilization and gamma-hemolysin (hlgABC) are highly up-regulated by USA300 during culture in human blood. Here we discuss the potential implication of these findings and the possible role of gamma-hemolysin in the success of S. aureus as a human pathogen.
Rodgers, G M; Barrera, E; Martin, R R
A patient with hemoglobin SC disease and cholelithiasis was found to have Bacillus cereus bacteremia. Hemolytic anemia developed, for which common causes of hemolysis were excluded, suggesting a relationship with the bacteremia. Following in vitro incubation, type O erythrocytes were hemolyzed by the culture, but not by a bacteria-free filtrate. This case confirms the association between sickle cell disorders and cholelithiasis with B cereus infections. In addition, it provides evidence for in vivo hemolysis with B cereus bacteremia, an organism not previously associated with hemolytic anemia.
Felipe F. Tuon
Full Text Available The objective of this study was to determine risk factors associated with mortality in patients with nosocomial Escherichia coli bacteremia from January 2009 to January 2011. In a retrospective study the medical records of 88 patients over 18 years with nosocomial bacteremia caused by E. coli were analyzed. In univariate analysis several risk factors, including chronic renal failure, altered mental status, leukocytosis, and higher Charlson index of comorbidities were associated with mortality. In multivariate analysis only altered mental status remained independently associated with mortality. Mental confusion can be a risk factor for mortality in patients with E. coli bacteremia.
Medrano-Juarez, R. M.; Sotello, D.; D'Cuhna, L.; Payne, J. D.
We present a case of acute hemolytic anemia, renal failure, and Clostridium perfringens bacteremia in a patient with acute myelogenous leukemia. The high fatality of C. perfringens bacteremia requires that clinicians recognize and rapidly treat patients at risk for this infection. Although other hemolytic processes are in the differential diagnosis of these events, the presence of high fever, chills, and rapidly positive blood cultures may help narrow the diagnosis. Most cases of C. perfringens bacteremia have a concomitant coinfection, which makes broad spectrum empiric therapy essential. There is a high mortality rate of C. perfringens infections associated with leukemia.
Hur, Jaehyung; Lee, Anna; Hong, Jeongmin; Jo, Won-Yong; Cho, Oh-Hyun; Kim, Sunjoo; Bae, In-Gyu
Staphylococcus saprophyticus is a common pathogen of acute urinary tract infection (UTI) in young females. However, S. saprophyticus bacteremia originating from UTI is very rare and has not been reported in Korea. We report a case of S. saprophyticus bacteremia from UTI in a 60-year-old female with a urinary stone treated successfully with intravenous ciprofloxacin, and review the cases of S. saprophyticus bacteremia reported in the literature. Thus, the microorganism may cause invasive infection and should be considered when S. saprophyticus is isolated from blood cultures in patients with UTI.
Full Text Available Mao Hagihara1, Takumi Umemura1, Takeshi Mori1,2, Hiroshige Mikamo11Department of Infection Control and Prevention, Aichi Medical University School of Medicine, Nagakute, Aichi, Japan; 2Division of Pharmaceutical Science, Faculty of Pharmacy, Meijo University, Nagoya, Aichi, JapanAbstract: Daptomycin is a lipoglycopeptide antibacterial drug that is rapidly bactericidal for methicillin-resistant Staphylococcus aureus (MRSA infection and has antibiotic activity against a wide range of Gram-positive organisms. It has been approved by the Ministry of Health, Labor and Welfare in Japan for the treatment for bacteremia, right-sided endocarditis, and skin and skin-structure infections, such as necrotizing fasciitis, due to MRSA on the basis of a Phase III trial conducted in Japan since July, 2011. In Japanese Phase I and III trials, daptomycin therapy given at 4 mg/kg and 6 mg/kg once per day was well tolerated and effective as standard therapy for the treatment of acute bacterial skin and skin-structure infections and bacteremia caused by MRSA, but side effects remain to be evaluated in large-scale trials.Keywords: daptomycin, methicillin-resistant Staphylococcus aureus (MRSA, Japan
Walcher, Georg; Gonano, Monika; Kümmel, Judith; Barker, Gary C; Lebl, Karin; Bereuter, Othmar; Ehling-Schulz, Monika; Wagner, Martin; Stessl, Beatrix
Sampling approaches following the dairy chain, including microbiological hygiene status of critical processing steps and physicochemical parameters, contribute to our understanding of how Staphylococcus aureus contamination risks can be minimised. Such a sampling approach was adopted in this study, together with rapid culture-independent quantification of Staph. aureus to supplement standard microbiological methods. A regional cheese production chain, involving 18 farms, was sampled on two separate occasions. Overall, 51·4% of bulk milk samples were found to be Staph. aureus positive, most of them (34·3%) at the limit of culture-based detection. Staph. aureus positive samples >100 cfu/ml were recorded in 17·1% of bulk milk samples collected mainly during the sampling in November. A higher number of Staph. aureus positive bulk milk samples (94·3%) were detected after applying the culture-independent approach. A concentration effect of Staph. aureus was observed during curd processing. Staph. aureus were not consistently detectable with cultural methods during the late ripening phase, but >100 Staph. aureus cell equivalents (CE)/ml or g were quantifiable by the culture-independent approach until the end of ripening. Enterotoxin gene PCR and pulsed-field gel electrophoresis (PFGE) typing provided evidence that livestock adapted strains of Staph. aureus mostly dominate the post processing level and substantiates the belief that animal hygiene plays a pivotal role in minimising the risk of Staph. aureus associated contamination in cheese making. Therefore, the actual data strongly support the need for additional sampling activities and recording of physicochemical parameters during semi-hard cheese-making and cheese ripening, to estimate the risk of Staph. aureus contamination before consumption.
Ternavasio-de la Vega, Hugo-Guillermo; Mateos-Díaz, Ana-María; Martinez, Jose-Antonio; Almela, Manel; Cobos-Trigueros, Nazaret; Morata, Laura; De-la-Calle, Cristina; Sala, Marta; Mensa, Josep; Marcos, Miguel; Soriano, Alex
The role of linezolid in empirical therapy of suspected bacteremia remains unclear. The aim of this study was to evaluate the influence of empirical use of linezolid or glycopeptides in addition to other antibiotics on the 30-day mortality rates in patients with Gram-negative bacteremia. For this purpose, 1,126 patients with Gram-negative bacteremia in the Hospital Clinic of Barcelona from 2000 to 2012 were included in this study. In order to compare the mortality rates between patients who received linezolid or glycopeptides, the propensity scores on baseline variables were used to balance the treatment groups, and both propensity score matching and propensity-adjusted logistic regression were used to compare the 30-day mortality rates between the groups. The overall 30-day mortality rate was 16.0% during the study period. Sixty-eight patients received empirical treatment with linezolid, and 1,058 received glycopeptides. The propensity score matching included 64 patients in each treatment group. After matching, the mortality rates were 14.1% (9/64) in patients who received glycopeptides and 21.9% (14/64) in those who received linezolid, and a nonsignificant association between empirical linezolid treatment and mortality rate (odds ratio [OR], 1.63; 95% confidence interval [CI], 0.69 to 3.82; P = 0.275, McNemar's test) was found. This association remained nonsignificant when variables that remained unbalanced after matching were included in a conditional logistic regression model. Further, the stratified propensity score analysis did not show any significant relationship between empirical linezolid treatment and the mortality rate after adjustment by propensity score quintiles or other variables potentially associated with mortality. In conclusion, the propensity score analysis showed that empirical treatment with linezolid compared with that with glycopeptides was not associated with 30-day mortality rates in patients with Gram-negative bacteremia.
Cadieux, Brigitte; Vijayakumaran, Vithooshan; Bernards, Mark A; McGavin, Martin J; Heinrichs, David E
Part of the human host innate immune response involves the secretion of bactericidal lipids on the skin and delivery of triglycerides into abscesses to control invading pathogens. Two Staphylococcus aureus lipases, named SAL1 and SAL2, were identified in the community-associated methicillin-resistant S. aureus strain USA300, which, presumably, are produced and function to degrade triglycerides to release free fatty acids. We show that the SAL2 lipase is one of the most abundant proteins secreted by USA300 and is proteolytically processed from the 72-kDa proSAL2 to the 44-kDa mature SAL2 by the metalloprotease aureolysin. We show that spent culture supernatants had lipase activity on both short- and long-chain fatty acid substrates and that deletion of gehB, encoding SAL2, resulted in the complete loss of these activities. With the use of gas chromatography-mass spectrometry, we show that SAL2 hydrolyzed trilinolein to linoleic acid, a fatty acid with known antistaphylococcal properties. When added to cultures of USA300, trilinolein and, to a lesser extent, triolein inhibited growth in a SAL2-dependent manner. This effect was shown to be due to the enzymatic activity of SAL2 on these triglycerides, since the catalytically inactive SAL2 Ser412Ala mutant was incapable of hydrolyzing the triglycerides or yielding delayed growth in their presence. Overall, these results reveal that SAL2 hydrolyzes triglycerides of both short- and long-chain fatty acids and that the released free fatty acids have the potential to cause significant delays in growth, depending on the chemical nature of the free fatty acid.
Hernaiz, C; Picardo, A; Alos, J I; Gomez-Garces, J L
We present a case of Bacillus cereus bacteremia and catheter infection in an immunocompetent patient subjected to abdominal surgery, who recovered following central catheter removal and treatment with piperacillin/tazobactam.
Wendy Irene Sligl
Conclusions: ICU-acquired Gram-negative bacteremia is associated with high mortality. Resistance to ciprofloxacin, piperacillin/tazobactam, and carbapenems was common. Coronary artery disease, immune suppression, and inadequate empiric antimicrobial therapy were independently associated with increased mortality.
Thønnings, Sara; Andersen, Christian Østergaard
Optimal antibiotic treatment strategies of Haemophilus infections are still needed. Therefore, 30-day case fatality rate (CFR) of Haemophilus bacteremia and efficacy of various antibiotic treatment regimes were studied....
Yamamoto, Kei; Hayakawa, Kayoko; Nagamatsu, Maki; Fujiya, Yoshihiro; Mawatari, Momoko; Kutsuna, Satoshi; Takeshita, Nozomi; Tamura, Saeko; Mezaki, Kazuhisa; Ohmagari, Norio
An 87-year-old man with poorly controlled diabetic mellitus presented with fever, bedsores, and elevated hepatobiliary enzyme levels. He was diagnosed with bacteremia with acute cholangitis due to Arthrobacter species, which are Gram-positive, aerobic, catalase-positive, coryneform bacteria belonging to the family Microbacteriaceae. Doripenem and subsequencial sulbactam/ampicillin treatment were used for the acute cholangitis, and the bacteremia was treated with a 2-week course of vancomycin. The bacteremia was misidentified by the phenotyping assay (API Coryne test), but was identified as Arthrobacter creatinolyticus by 16S rRNA and matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry. To our knowledge, this is the first report of a human case of A. creatinolyticus bacteremia.
Luiza Helena Urso Pitassi
Full Text Available Bartonella species are blood-borne, re-emerging organisms, capable of causing prolonged infection with diverse disease manifestations, from asymptomatic bacteremia to chronic debilitating disease and death. This pathogen can survive for over a month in stored blood. However, its prevalence among blood donors is unknown, and screening of blood supplies for this pathogen is not routinely performed. We investigated Bartonella spp. prevalence in 500 blood donors from Campinas, Brazil, based on a cross-sectional design. Blood samples were inoculated into an enrichment liquid growth medium and sub-inoculated onto blood agar. Liquid culture samples and Gram-negative isolates were tested using a genus specific ITS PCR with amplicons sequenced for species identification. Bartonella henselae and Bartonella quintana antibodies were assayed by indirect immunofluorescence. B. henselae was isolated from six donors (1.2%. Sixteen donors (3.2% were Bartonella-PCR positive after culture in liquid or on solid media, with 15 donors infected with B. henselae and one donor infected with Bartonella clarridgeiae. Antibodies against B. henselae or B. quintana were found in 16% and 32% of 500 blood donors, respectively. Serology was not associated with infection, with only three of 16 Bartonella-infected subjects seropositive for B. henselae or B. quintana. Bartonella DNA was present in the bloodstream of approximately one out of 30 donors from a major blood bank in South America. Negative serology does not rule out Bartonella spp. infection in healthy subjects. Using a combination of liquid and solid cultures, PCR, and DNA sequencing, this study documents for the first time that Bartonella spp. bacteremia occurs in asymptomatic blood donors. Our findings support further evaluation of Bartonella spp. transmission which can occur through blood transfusions.
Rettew, Andrew; Shaikh, Bilal; Abdulkareem, Abdullateef
Worldwide, Shigellosis is a significant public health issue, associated with nearly one million deaths annually. About half a million cases of Shigella infection are reported annually in the United States. Shigella bacteremia is uncommon and generally seen in children and immunocompromised adults. We present a case of a Shigella sonnei bacteremia with marked hepatic derangement in a 27-year-old previously healthy homosexual male with history of Roux-en-Y gastric bypass, who presented to the emergency room with a 4-day history of loose watery stool, abdominal cramps, nausea and vomiting, and yellow skin of 2-day duration. He reports similar diarrhea illness in two close contacts in preceding days. On examination, he was fully oriented but dehydrated, icteric, and febrile. Laboratory data revealed WBC of 2200/μL, elevated AST and ALT (201 IU/L, 73 IU/L resp.), normal alkaline phosphatase, elevated total and direct bilirubin of 8.2 mg/dL and 4.4 mg/dL, albumin of 3.2 g/dL, INR of 2.9, prothrombin time of 31.7, and platelet of 96,000/μL. Workup for infectious, autoimmune and medication-induced hepatitis, Wilson's disease, and hemochromatosis was negative. Abdominal ultrasound and computed tomography of the abdomen showed hepatic steatosis and right-sided colitis. Stool and blood cultures were positive for Shigella sonnei. He was treated with ciprofloxacin with improvement in liver function. Follow-up blood test 4 months later was within normal limits. PMID:28326205
Ito, Ryota; Shindo, Yuichiro; Kobayashi, Daisuke; Ando, Masahiko; Jin, Wanchun; Wachino, Jun-ichi; Yamada, Keiko; Kimura, Kouji; Yagi, Tetsuya; Hasegawa, Yoshinori; Arakawa, Yoshichika
Some important virulence factors have been elucidated in Klebsiella pneumoniae infections. We investigated the relationship between virulence factors and multilocus sequence types (STs) and assessed the risk factors for bacteremia in patients with pneumonia due to K. pneumoniae. From April 2004 through April 2012, a total of 120 K. pneumoniae isolates from patients with pneumonia (23 with bacteremia and 97 without bacteremia) were collected from 10 medical institutions in Japan. Additionally, 10 strains of K. pneumoniae serotype K2 that were isolated >30 years ago were included in this study. These isolates were characterized using multilocus sequence typing (MLST), and the characteristics of their virulence factors, such as hypermucoviscosity phenotype and RmpA and aerobactin production between patients with and without bacteremia, were examined. MLST analysis was performed on the 120 isolates from patients with pneumonia, and some sequence type groups were defined as genetic lineages (GLs). GL65 was more prevalent among patients with bacteremia (21.7%) than in those without bacteremia (7.2%). The majority of the strains with serotype K2 were classified into GL14 or GL65, and rmpA and the gene for aerobactin were present in all GL65-K2 strains but absent in all GL14-K2 strains. In a multivariate analysis, the independent risk factors for bacteremia included GL65 (adjusted odds ratio [AOR], 9.46; 95% confidence interval [CI], 1.81 to 49.31), as well as neoplastic disease (AOR, 9.94; 95% CI, 2.61 to 37.92), immunosuppression (AOR, 17.85; 95% CI, 1.49 to 214.17), and hypoalbuminemia (AOR, 4.76; 95% CI, 1.29 to 17.61). GL65 was more prevalent among patients with bacteremia and was associated with the virulence factors of K. pneumoniae.
Gisele Peirano; Johann DD. Pitout; Laupland, Kevin B.; Bonnie Meatherall; Daniel B Gregson
The characteristics of hypermucoviscosity isolates among Klebsiella pneumoniae causing community-acquired bacteremia were investigated. The hypermucoviscous phenotype was present in 8.2% of K pneumoniae isolates, and was associated with rmpA and the K2 serotype; liver abscesses were the most common clinical presentation. The present analysis represents the first population-based surveillance study of hypermucoviscosity among K pneumoniae causing bacteremia.
Rosenbaum, G.S.; Calubiran, O.; Cunha, B.A. (Winthrop-Univ. Hospital, Mineola, NY (USA))
A young woman with a history of sick sinus syndrome and placement of a permanent pacemaker 6 months before admission had fever and Haemophilus parainfluenzae bacteremia. A gallium scan localized the infection to the site of the pacemaker wire. Echocardiograms were negative for any vegetations. The patient responded to cefotaxime and trimethoprim-sulfamethoxazole therapy. We believe that this is the first case of H. parainfluenzae bacteremia associated with a pacemaker wire and localized by gallium scan.
Eitan Naaman Berezin
Full Text Available We reviewed the incidence of occult bacteremia, to identify the most frequent etiological agents of bacteremias in otherwise healthy children from one month to 10 years old, who had fever of unknown origin attended at the emergency ward of an urban, university-affiliated pediatric referral center. This was a retrospective medical record review, evaluating children with fever. Data were collected from the initial visit, when blood cultures, hematological properties and hemosedimentation rates were examined. Fever was considered as the highest temperature assessed in the hospital or reported by the responsible adult. Occult bacteremia was discovered in 1.4% of the 1,051 children evaluated, and the most common etiologic agent was Streptococcus pneumoniae. Total leukocyte count and blood sedimentation rates greater than 30 mm³ were not predictive factors for occult bacteremia. Fever greater than 39ºC was the most important factor for predicting occult bacteremia (P<0.001. The presence of occult bacteremia was significantly correlated with patient hospitalization.
Gerrish, Robert S; Gill, Ann L; Fowler, Vance G; Gill, Steven R
We describe the development and application of a Pooled Suppression Subtractive Hybridization (PSSH) method to describe differences between the genomic content of a pool of clinical Staphylococcus aureus isolates and a sequenced reference strain. In comparative bacterial genomics, Suppression Subtractive Hybridization (SSH) is normally utilized to compare genomic features or expression profiles of one strain versus another, which limits its ability to analyze communities of isolates. However, a PSSH approach theoretically enables the user to characterize the entirety of gene content unique to a related group of isolates in a single reaction. These unique fragments may then be linked to individual isolates through standard PCR. This method was applied to examine the genomic diversity found in pools of S.aureus isolates associated with complicated bacteremia infections leading to endocarditis and osteomyelitis. Across four pools of 10 isolates each, four hundred and twenty seven fragments not found in or significantly divergent from the S. aureus NCTC 8325 reference genome were detected. These fragments could be linked to individual strains within its pool by PCR. This is the first use of PSSH to examine the S. aureus pangenome. We propose that PSSH is a powerful tool for researchers interested in rapidly comparing the genomic content of multiple unstudied isolates.
Imafuku, A; Araoka, H; Tanaka, K; Marui, Y; Sawa, N; Ubara, Y; Takaichi, K; Ishii, Y; Tomikawa, S
Helicobacter cinaedi can cause bacteremia mainly in immunocompromised patients. We present the clinical characteristics of H. cinaedi bacteremia in 4 renal transplant patients. Interestingly, all cases showed triggers of bacterial translocation: 2 cases developed after colonic perforation caused by diverticulitis, 1 case developed post cholecystectomy, and the remaining patient had chronic diarrhea. Accordingly, bacterial translocation caused by severe gastrointestinal complication could be a cause of H. cinaedi bacteremia.
Bentivegna, Erminia; Citarrella, Emanuele; Vivaldi, Roberto; De Luca, Dario; Maira, Giovanna Grazia; Casuccio, Alessandra; Di Carlo, Paola
Prostaglandins appear to reduce biofilm formation and chronicization of infections, and stimulate a rapid and effective clearance of infecting micro-organisms. We report a case of recovery from methicillin-susceptible Staphylococcus aureus (MSSA) osteomyelitis after multidisciplinary management with antibiotics, anti-thrombotics and prostaglandin E1 (PGE1) vasodilator, in a patient with tibial plateau fracture repaired with internal fixation devices. A 47-year-old HIV-negative male with chronic ulcer on the proximal third of the left leg was admitted to the Orthopaedic Unit of the Orestano Clinic in Palermo, Italy, for suspected osteomyelitis. A biopsy of the skin ulcer and blood cultures were performed and resulted positive for MSSA. Labelled leukocyte scintigraphy confirmed osteomyelitis. No clinical improvement was observed after combined antibiotic treatment with rifampicin plus trimethoprim-sulfamethoxazole. The patient underwent a 4-day therapeutic cycle: PGE1 (alprostadil 60 mg/day IV) combined with nadroparin calcium plus gentamicin, followed by treatment with aminaftone plus sulodexide plus levofloxacin. At discharge, the patient's painful symptoms had completely resolved and the ulcer had cicatrized; recovery from osteomyelitis was confirmed by scintigraphy. This treatment protocol including PGE1 may result in a significant improvement in quality of life and functional status of patients with a reduction in direct and indirect costs and economic benefit for the National Health Service.
Viacheslav, Ilyin; Kiryukhina, Nataliya
Nasal carriage of Staphylococcus aureus is a well-documented risk factor of infection and inflammation of the skin, soft tissues and bacteremia. It is also known that most often etiology of these disorders is associated with autoinfection. The present-day methods of opportunistic pathogens eradication from the nasal cavity are based principally on the use of antiseptic and antibacterial agents. For instance, a local antibiotic mupirocin in the form of nasal ointment is considered to be the gold standard for the treatment of S. aureus carriage. The literature describes investigations showing how mupirocin can strengthen antibiotic resistance in S. aureus strains, including those with methicillin resistance (MRSA). It is also common knowledge that recolonization of the nasal mucous membrane takes place within several months after mupirocin treatment. This circumstance dictates the necessity to look for alternative ways of preventing the S. aureus carriage and methods of elimination. One of the methods of nasal S. aureus elimination is implantation of nonpathogenic microorganisms which will extrude opportunistic pathogens without impinging the symbiotic microbiota. Effectiveness of saline suspension of Corynebacterium pseudodiphtheriticum containing spray was assessed in a several chamber experiments with simulation of some spaceflight factors (dry immersion, isolation). Various schemes of application of preparations were applied. In all cases of corynebacteria application the strong inhibiting effect against S. aureus was detected. This fact opens a prospect of using nonpathogenic corynebacteria as a nasal probiotic. Administration of the nasal corynebacteria spray possibly prevented cross-infection by MRSA and appearance of staphylococcal infection. Further pre-clinical and clinical study of this bacterial therapy method is under development.
Zhang, Xin; Liu, Yu; Gao, Yaping; Dong, Jie; Mu, Chunhua; Lu, Qiang; Shao, Ningsheng; Yang, Guang
Several fibrinogen binding proteins (Fibs) play important roles in the pathogenesis of Staphylococcus aureus (S. aureus). Most Fibs can promote the aggregation of platelets during infection, but the extracellular fibrinogen-binding protein (Efb) is an exception. It is reported that Efb can specifically bind fibrinogen and inhibit the aggregation of platelet with its N terminal. However, the biological significance of platelet aggregation inhibition in the infection caused by S. aureus is unclear until now. Here, we demonstrated that the persistence and aggregation of platelets were important for killing S. aureus in whole blood. It was found that the N terminal of Efb (EfbN) and platelets inhibitors could increase the survival of S. aureus in whole blood. The study in vivo also showed that EfbN and platelets inhibitors could reduce the killing of S. aureus and increase the lethality rate of S. aureus in the acute infection mouse model.
Felipe F. Tuon
Full Text Available INTRODUCTION: The aim of this study was to determine risk factors for acquiring carbapenemresistant Pseudomonas aeruginosa bacteremia (CR-PA and factors associated with in-hospital mortality. METHODS: Seventy-seven cases of bacteremia caused by P. aeruginosa were evaluated in a hospital with high incidence of CR-PA. Clinical and laboratorial factors, and previous use of antibiotics were also evaluated. In one analysis, CR-PA and carbapenem-susceptible P. aeruginosa (CS-PA bacteremia were compared. A second analysis compared patients who died with survivors. RESULTS: Among 77 P. aeruginosa bacteremia, 29 were caused by CR-PA. Admission to the intensive care unit, higher number of total leukocytes, and previous use of carbapenem were statistically associated with CR-PA. In the multivariate analysis, only previous use of carbapenem (including ertapenem turned out to be a risk factor for CR-PA (p = 0.014. The 30-day mortality of patients with P. aeruginosa bloodstream infection was 44.8% for CS-PA and 54.2% for patients with CR-PA (p = 0.288. Chronic renal failure, admission to the intensive care unit, mechanical ventilation, and central venous catheter were risk factors for mortality. Incorrect treatment increased mortality of patients with bacteremia caused by CS-PA, but not for CR-SA. The odd ratio of mortality associated with incorrect therapy in patients with CS-PA was 3.30 (1.01-10.82; p = 0.043. The mortality of patients with bacteremia caused by CR-PA was unexpectedly similar regardless of antimicrobial treatment adequacy. CONCLUSION: Appropriate treatment for CS-PA bacteremia initiated within the first 24 hours was associated with lower mortality, but this cannot be extrapolated for CR-PA.
Stewart, Audra; Dyamenahalli, Umesh; Greenberg, S Bruce; Drummond-Webb, Jonathan
We present the case of a 6-month-old previously healthy girl who presented with high fever, labored breathing, and an enlarged cardiac silhouette on her chest radiograph. Comprehensive evaluation discovered a ductus arteriosus aneurysm and pericardial effusion with methicillin-resistant Staphylococcus aureus bacteremia. Despite pericardiocentesis and appropriate intravenous antibiotics, there was rapid enlargement of the aneurysm and accumulation of echogenic material within the ductus arteriosus aneurysm. Infected aneurysm rupture was identified during emergency surgery. This infant also had vocal cord paresis, a likely complication of the surgery. The clinical course, diagnosis, and treatment of this patient are discussed. Infection of a ductus arteriosus or an infected ductal arteriosus aneurysm is a rare and potentially fatal clinical entity. In the era of increasing community-acquired methicillin-resistant S aureus infections, this is a diagnosis that requires a high index of suspicion.
Togawa, Atsushi; Toh, Hiromi; Onozawa, Kyoko; Yoshimura, Michinobu; Tokushige, Chiemi; Shimono, Nobuyuki; Takata, Tohru; Tamura, Kazuo
Ninety-four episodes of Klebsiella pneumoniae bloodstream infection were identified at a university hospital in Japan. After excluding extended-spectrum beta lactamase-producing strains, 83 blood isolates from these patients were assayed in terms of their bacterial phenotypes such as the mucoid and hypermucoviscosity phenotypes. Bacterial phenotypes were correlated with the patients' clinical manifestations. The hypermucoviscosity phenotype was significantly associated with septic shock at the onset of infections (odds ratio, 15.92; 95% confidence interval, 1.27-468.12), but was not associated with liver abscess formation. Mortality was determined by the presence of septic shock. RmpA gene was associated with the induction of the hypermucoviscosity phenotype. These results reveal unique roles of bacterial phenotypes on the patient's clinical condition in K. pneumoniae bacteremia.
Grande, Rossella; Nistico, Laura; Sambanthamoorthy, Karthik; Longwell, Mark; Iannitelli, Antonio; Cellini, Luigina; Di Stefano, Antonio; Hall Stoodley, Luanne; Stoodley, Paul
Extracellular DNA (eDNA) is an important component of the extracellular polymeric substance matrix and is important in the establishment and persistence of Staphylococcus aureus UAMS-1 biofilms. The aim of the study was to determine the temporal expression of genes involved in early biofilm formation and eDNA production. We used qPCR to investigate expression of agrB, which is associated with secreted virulence factors and biofilm dispersal, cidA, which is associated with biofilm adherence and genomic DNA release, and alsS, which is associated with cell lysis, eDNA release and acid tolerance. The contribution of eDNA to the stability of the biofilm matrix was assessed by digesting with DNase I (Pulmozyme) and quantifying structure by confocal microscopy and comstat image analysis. AgrB expression initially increased at 24 h but then dramatically decreased at 72 h in an inverse relationship to biomass, supporting its role in regulating biofilm dispersal. cidA and alsS expression steadily increased over 72 h, suggesting that eDNA was an important component of early biofilm development. DNase I had no effect on biomass, but did cause the biofilms to become more heterogeneous. Carbohydrates in the matrix appeared to play an important role in structural stability.
Park, Hyun; Jang, Ki Jun; Jang, Won; Park, Sang Hoon; Park, Ji Young; Jeon, Tae Joo; Oh, Tae Hoon; Shin, Won Chang; Choi, Won-Choong; Sinn, Dong Hyun
AIM: To analyze whether prompt and appropriate empirical antibiotic (AEA) use is associated with mortality in cirrhotic patients with bacteremia. METHODS: A total of 102 episodes of bacteremia in 72 patients with cirrhosis were analyzed. AEA was defined as a using or starting an antibiotic appropriate to the isolated pathogen at the time of bacteremia. The primary endpoint was 30-d mortality. RESULTS: The mortality rate at 30 d was 30.4% (31/102 episodes). Use of AEA was associated with better survival at 30 d (76.5% vs 46.9%, P = 0.05), and inappropriate empirical antibiotic (IEA) use was an independent factor associated with increased mortality (OR = 3.24; 95%CI: 1.50-7.00; P = 0.003, adjusted for age, sex, Child-Pugh Class, gastrointestinal bleeding, presence of septic shock). IEA use was more frequent when the isolated pathogen was a multiresistant pathogen, and when infection was healthcare-related or hospital-acquired. CONCLUSION: AEA use was associated with increased survival of cirrhotic patients who developed bacteremia. Strategies for AEA use, tailored according to the local epidemiological patterns, are needed to improve survival of cirrhotic patients with bacteremia. PMID:25834324
Montassier, E; Batard, E; Gastinne, T; Potel, G; de La Cochetière, M F
Bacteremia remains a major cause of life-threatening complication in patients with cancer. Significant changes in the spectrum of microorganisms isolated from blood culture have been reported in cancer patients over the past years. The aim of our systematic review was to inventory the recent trends in epidemiology and antibiotic resistance of microorganisms causing bacteremia in cancer patients. Data for this review was identified by searches of Medline, Scopus and Cochrane Library for indexed articles and abstracts published in English since 2008. The principal search terms were: "antimicrobial resistance", "bacteremia", "bacterial epidemiology", "bloodstream infection", "cancer patients", "carbapenem resistance", "Escherichia coli resistance", "extended-spectrum β-lactamase producing E. coli", "febrile neutropenia", "fluoroquinolone resistance", "neutropenic cancer patient", "vancomycin-resistant Enterococcus", and "multidrug resistance". Boolean operators (NOT, AND, OR) were also used in succession to narrow and widen the search. Altogether, 27 articles were selected to be analyzed in the review. We found that Gram-negative bacteria were the most frequent pathogen isolated, particularly in studies with minimal use of antibiotic prophylaxis. Another important trend is the extensive emergence of antimicrobial-resistant strains associated with increased risk of morbidity, mortality and cost. This increasing incidence of antibiotic resistance has been reported in Gram-negative bacteria as well as in Gram-positive bacteria. This exhaustive review, reporting the recent findings in epidemiology and antibiotic resistance of bacteremia in cancer patients, highlights the necessity of local continuous surveillance of bacteremia and stringent enforcement of antibiotic stewardship programs in cancer patients.
Gürol, Gölnül; Çiftci, İhsan Hakki; Terizi, Huseyin Agah; Atasoy, Ali Rıza; Ozbek, Ahmet; Köroğlu, Mehmet
Bacteremia and sepsis are common causes of morbidity and mortality worldwide, with incorrect or delayed diagnoses being associated with increased mortality. New tests or markers that allow a more rapid and less costly detection of bacteremia and sepsis have been investigated. The aim of this study was to clarify the cutoff value of the neutrophillymphocyte ratio (NLR) according to procalcitonin (PCT) level in the decision-making processes for bacteremia and sepsis. In addition, other white blood cell subgroup parameters, which are assessed in all hospitals, for bacteremia and sepsis were explored. This retrospective study included 1,468 patients with suspected bacteremia and sepsis. Patients were grouped according to the following PCT criteria: levels sepsis group), and >10 ng/ml (sepsis shock group). One important finding of this study, which will serve as a baseline to measure future progress, is the presence of many gaps in the information on pathogens that constitute a major health risk. In addition, clinical decisions are generally not coordinated, compromising the ability to assess and monitor a situation. This report represents the first study to determine the limits of the use of NLR in the diagnosis of infection or sepsis using a cutoff value of <5 when sufficient exclusion criteria are used.
Søgaard, Kirstine K; Farkas, Dóra K; Søgaard, Mette;
OBJECTIVES: Gram-negative bacteremia may be a harbinger of occult cancer. We examined the risk of cancer following hospitalization with bacteremia. METHODS: Using medical databases, we conducted a nationwide population-based cohort study of all Danes with a discharge diagnosis of Gram-negative ba...... of follow-up, the SIR declined to 1.13 (95% CI: 1.05-1.20). CONCLUSIONS: Gram-negative bacteremia is a clinical marker of occult cancer.......OBJECTIVES: Gram-negative bacteremia may be a harbinger of occult cancer. We examined the risk of cancer following hospitalization with bacteremia. METHODS: Using medical databases, we conducted a nationwide population-based cohort study of all Danes with a discharge diagnosis of Gram...... of gastrointestinal cancer (3- to 13-fold higher), genitourinary cancer (4- to 10-fold higher), non-Hodgkin lymphoma (5-fold higher), non-specified metastatic cancer (5-fold higher), and breast and lung cancer (2-fold higher). The 6-12 months SIR for any cancer was 1.46 (95% CI: 1.22-1.72), and beyond 1 year...
Kumar Shukla, Sudhir; Rao, Toleti Subba
The dominant role of biofilm-associated protein (Bap) in Staphylococcus aureus biofilm development prompted us to investigate Bap as a potential target for proteinase-mediated biofilm dispersion. Biofilm assay in microtitre plates showed that proteinase K hampered the early adhesion of cells as well as biofilm development. Proteinase K treatment of 24- and 48-h-old biofilms showed enhanced dispersion of bap-positive S. aureus biofilm; however, proteinase K did not affect the bap-negative S. aureus biofilm. When antibiotics were used in combination with proteinase K, significant enhancement in antibiotic action was noticed against bap-positive S. aureus biofilm. This study establishes that antibiotics in combination with proteinase K can be used for controlling S. aureus biofilms in whose development Bap surface protein has a major role. We propose that Bap protein could be a potential target for therapeutic control of S. aureus infections (for example, bovine mastitis).
Koch, Kristoffer; Nørgaard, Mette; Schønheyder, Henrik Carl;
To examine the effect of socioeconomic status (SES) on mortality in patients with bacteremia and the underlying factors that may mediate differences in mortality.......To examine the effect of socioeconomic status (SES) on mortality in patients with bacteremia and the underlying factors that may mediate differences in mortality....
Song, Eun Hee; Park, Ki-Ho; Jang, Eun-Young; Lee, Eun Jung; Chong, Yong Pil; Cho, Oh-Hyun; Kim, Sung-Han; Lee, Sang-Oh; Sung, Heungsup; Kim, Mi-Na; Jeong, Jin-Yong; Kim, Yang Soo; Woo, Jun Hee; Choi, Sang-Ho
We compared the characteristics and outcomes of 172 Enterobacter cloacae bacteremia and 67 Enterobacter aerogenes bacteremia (EAB) cases. Antimicrobial resistance rates to E. cloacae were higher than those to E. aerogenes. However, EAB more frequently presented as septic shock and was associated with poorer outcomes.
R.R. Muder; C. Brennen; M.M. Wagener (Marilyn); A.M. Geotz
textabstractThe clinical features, microbiological characteristics, and outcomes of 163 episodes of bacteremia occurring at a long-term-care facility were evaluated. The rate of nosocomial bacteremia increased from 0.20 to 0.36 cases/1,000 patient-days from 1985 to 1989; there was a parallel increas
Tsai, Hsih-Yeh; Chen, Yen-Hsu; Tang, Hung-Jen; Huang, Chi-Chang; Liao, Chun-Hsing; Chu, Fang-Yeh; Chuang, Yin-Ching; Sheng, Wang-Huei; Ko, Wen-Chien; Hsueh, Po-Ren
This study was intended to delineate the role of carbapenems and piperacillin/tazobactam in treating bacteremia caused by extended-spectrum β-lactamase (ESBL)-producing Proteus mirabilis. We performed a multicenter and retrospective study of the patients with ESBL-producing P. mirabilis bacteremia. The outcomes of the patients treated by piperacillin/tazobactam or a carbapenem for at least 48 hours and the MICs of the prescribed drugs for these isolates were analyzed. Forty-seven patients with available clinical data were included. The overall 30-day mortality rate was 29.8%. All available isolates (n = 44) were susceptible to ertapenem, meropenem, and doripenem, and 95.6% were susceptible to piperacillin/tazobactam; however, only 11.4% of the isolates were susceptible to imipenem. Among the 3 patients infected with isolates exhibiting non-susceptibility to imipenem (MIC ≥2 mg/L) who were treated with imipenem, none died within 28 days. The 30-day (14.3% versus 23.1%, P = 0.65) or in-hospital (19.1% versus 30.8%, P = 0.68) mortality rate of 21 patients treated by a carbapenem was lower than that of 13 treated by piperacillin/tazobactam. However, among those treated by piperacillin/tazobactam, the mortality rate of those infected by the isolates with lower piperacillin/tazobactam MICs (≤0.5/4 mg/L) was lower than that of the isolates with MICs of ≥1/4 mg/L (0%, 0/7 versus 60%, 3/5; P = 0.045). ESBL-producing P. mirabilis bacteremia is associated with significant mortality, and carbapenem therapy could be regarded as the drugs of choice. The role of piperacillin/tazobactam, especially for the infections due to the isolates with an MIC ≤0.5/4 mg/L, warrants more clinical studies.
Delfani, Somayeh; Mohabati Mobarez, Ashraf; Imani Fooladi, Abbas Ali; Amani, Jafar; Emaneini, Mohammad
Staphylococcus aureus is one of the most important causes of nosocomial infections. An effective vaccine to prevent S. aureus infections is urgently required due to the dramatic increase in the number of antibiotic-resistant strains. In this report, we evaluated a newly recombinant protein composed of selected antigenic regions of clumping factor A (ClfA), iron surface determinant B (IsdB) and gamma hemolysin B (HlgB) of S. aureus and sequence coding for hydrophobic linkers between three domains. The recombinant gene was constructed in pET-28a (+) and expressed in Escherichia coli BL21. In addition, sequence coding for a His(6)-tag was added followed by a hybrid procedure of nickel chelate protein purification. Immunization of BALB/c mice with the recombinant protein ClfA-IsdB-Hlg evoked antigen-specific antibodies that could opsonize S. aureus cells, enhancing in vitro phagocytosis by macrophages. Vaccination with the recombinant protein also reduced the bacterial load recovered from mice spleen samples and increased survival following the intraperitoneal challenge with pathogenic S. aureus compared to the control mice. Our results showed that the recombinant protein ClfA-IsdB-Hlg is a promising vaccine candidate for the prevention of S. aureus bacteremia infections.
Aroutcheva, Alla; Auclair, Julie; Frappier, Martin; Millette, Mathieu; Lolans, Karen; de Montigny, Danielle; Carrière, Serge; Sokalski, Stephen; Trick, William E; Weinstein, Robert A
There has been an increasing interest in the use of probiotic products for the prevention of Clostridium difficile infection (CDI). Bio-K+(®) is a commercial probiotic product comprising three strains of lactobacilli--Lactobacillus acidophilus CL1285(®), Lact. casei LBC80R(®) and Lact. rhamnosus CLR2(®)--that have been applied to prevent CDI. Generally considered as safe, lactobacilli have potential to cause bacteremia, endocarditis and other infections. The source of Lactobacillus bacteremia can be normal human flora or lactobacilli-containing probiotic. The aim of this study was to assess whether probiotic lactobacilli caused bacteremia and to show the value of molecular identification and typing techniques to determine probiotic and patient strain relatedness. We report an episode of Lactobacillus bacteremia in a 69-year-old man admitted to a hospital with severe congestive heart failure. During his hospitalization, he required long-term antibiotic therapy. Additionally, the patient received Bio-K+(®) probiotic as part of a quality improvement project to prevent CDI. Subsequently, Lactobacillus bacteremia occurred. Two independent blinded laboratory evaluations, using pulse field gel electrophoresis, 16S rRNA gene sequencing and DNA fingerprint analysis (rep-PCR), were performed to determine whether the recovered Lact. acidophilus originated from the probiotic product. Ultimately, the patient strain was identified as Lact. casei and both laboratories found no genetic relation between the patient's strain and any of the probiotic lactobacilli. This clinical case of lactobacillus bacteremia in the setting of probiotic exposure demonstrates the value of using discriminatory molecular methods to clearly determine whether there were a link between the patient's isolate and the probiotic strains.
Full Text Available Objectives: Many a times in clinical periodontology, the decision whether to prescribe prophylactic antibiotics or not , is perplexing.The present study was conducted to compare the bacteremias induced after periodontal flap surgeries with and without prophylactic antibiotics. Materials and Methods: The occurrence of postoperative bacteremia following periodontal flap surgery was studied in 30 patients. On these patients, 30 quadrant wise flap surgeries were carried out without any preoperative prophylactic antibiotics and 30 surgeries carried out after prophylactic administration of amoxycillin preoperatively. A blood sample was taken from each patient at the time of maximum surgical trauma and was cultured for micro-organisms and antibiotic sensitivity. Results: 18 out of 60 blood samples were positive for micro-organisms. There was a significant reduction in post operative bacteremia after amoxycillin prophylaxis (x - 7.96 with P< 0.01 as post operative bacteremia was found in 14 of the non medicated patients as compared to only 4 of the pre medicated patients. The micro-organisms encountered in the study are as follows:- 1 Staphylococcus albus coagulase negative, 2 Klebsiella, 3 Psedomonas aerugenosa, 4 Streptococcus viridans, 5 Alpha hemolytic streptococcus, 6 Neisseria catarrhalis Conclusion: On the basis of the study, it is concluded that the incidence of postoperative bacteremia following periodontal flap surgery is not as high as previously reported. The clinical results show that Amoxicillin is highly effective in reducing postoperative bacteremia in periodontal flap surgery and thus in preventing the possible sequelae (Infective Endocarditis and other systemic maladies in susceptible patients. However, cefotaxime and cephalexin may prove to be more effective in preventing the same.
Full Text Available This study is conducted to investigate the clinical characteristics of patients with bacteremia caused by Aeromonas species.Patients with bacteremia caused by Aeromonas species during the period 2009 to 2013 were identified from a computerized database of a regional hospital in southern Taiwan. The medical records of these patients were retrospectively reviewed.A total of 91 patients with bacteremia due to Aeromonas species were identified. In addition to 16 (17.6% primary bacteremia, the most common source of secondary infection is peritonitis (n = 27, 29.7%, followed by biliary tract infection (n = 18, 19.8%, and SSTI (n = 12, 13.2%, pneumonia (n = 9, 9.9%, catheter-related bloodstream infection (n = 5, 5.5%, and genitourinary tract infection (n = 4, 4.4%. A. hydrophila (n = 35, 38.5% was the most common pathogen, followed by A. veronii biovar sobria (n = 31, 34.1%, A. caviae (n = 14, 15.4%, and A. veronii biovar veronii (n = 9, 9.9%. Forty-three (47.3% patients were classified as healthcare-associated infections (HCAI causes by Aeromonas species, and patients with HCAI were more likely to have cancer, and receive immunosuppressant than patients with community-acquired bacteremia. The overall outcomes, including rate of ICU admission, acute respiratory failure, and mortality were 33.3%, 28.6%, and 23.1%, respectively. Multivariate analysis showed that the in-hospital day mortality was significantly associated only with underlying cancer (P <.001, and initial shock (P <.001.Aeromonas species should be considered one of the causative pathogens of healthcare-associated bacteremia, especially in immunocompromised patients. In addition, it can be associated with high fatality. Cancer and initial shock were the poor prognostic factors.
Aydemir, Zeynep Alp; Ozdemir, Nihal; Celik, Nigar; Celkan, Tiraje
Alcaligenes xylosoxidans which is an aerobic, non-fermentative gram-negative bacillus found in aqueous environments and human flora, can lead to opportunistic infections. It causes infections in elderly, immunocompromised patients, patients with chronic disorders or premature infants. In this report, a case of A. xylosoxidans bacteremia that developed in a child with acute lymphoblastic leukemia (ALL) was presented. Four-years-old male patient under ALL induction therapy was admitted with symptoms of lethargy, headache, somnolence, and fever (39 degrees C). Cerebrospinal fluid, blood, throat and urine cultures were taken from the patient and empirical treatment with sulbactam cefoperazon and amikacin was initiated. Blood cultures in BacT Alert 3D (Bio Merieux, France) revealed the growth of a gram-negative coccobacillus. The agent which was non-fermentative, indol and H2S negative, was identified as A. xylosoxidans by API 20 NE (Bio Merieux, France). Since fever continued under the current antibiotic treatment, the therapy was switched to imipenem (90 mg/kg 3x/day) and the patient's condition improved markedly after 24 hours. Disc diffusion susceptibility testing of the isolate revealed that it was resistant to ampicillin, cephalothin, cefuroxime, cefoxitin, cefotaxime, amikacin, netilmicin and gentamicin; susceptible to amoxicillin clavulanate, piperacillin tazobactam, seftazidime, cefepime, imipenem and ciprofloxacin. Following 14 days of imipenem therapy, the patient recovered and discharged from the hospital on routine follow-up. It is important to consider A. xylosoxidans as a possible causative agent particularly in the infections that develop in high risk patients at oncology, dialysis and neonatal intensive care units.
Cardenas, Paul A; Alarcón, Marta; Narvaez, Inés; Salazar, Ramiro; Falconí, Guillermo; Espinel, Mauricio; Trueba, Gabriel
Staphylococcus aureus is a frequent cause of nosocomial pneumonia and bacteremia worldwide. Classical and molecular epidemiology approaches were used to study a S. aureus outbreak in the intensive care unit (ICU) of one of the largest public hospitals in Quito. Staphylococcus aureus isolates from 17 patients and 19 potential carriers from the staff were collected from March 2007 to February 2008 and analyzed by pulsed-field gel electrophoresis (PFGE) to determine their clonal relationships. During this period the hospital reported 16 cases of hospital-acquired staphylococcal pneumonia and an apparent outbreak occurred from June to September 2007. DNA from these isolates formed six different PFGE patterns: four clonal groups, and two groups of clonally related isolates. Molecular typing failed to identify any staphylococcal reservoir among staff members. The current study suggested that a staphylococcal outbreak that occurred in the summer of 2007 was caused by different bacterial clones, although some clones were shared by two patients. Historical analysis of the staphylococcal infections in the ICU showed a higher incidence during the summer months, which coincided with the programmed personnel shift. This observation suggests that outbreaks might be produced by the introduction of improperly trained personnel.
Full Text Available Although central vascular catheters (CVC are indispensable in modern medicine, they are an important risk factor for primary bacteremias. We examined the incidence and risk factors associated with catheter-related bloodstream infection (CR-BSI caused by Staphylococcus aureus in surgical patients. A prospective study was carried out in the Hospital das Clínicas da Universidade Federal de Uberlândia (HC-UFU from September 2000 to December 2002. The skin insertion site, catheter tip, and blood were microbiologically analyzed. Demographics and risk factors were recorded for each patient, and cultures were identified phenotypically. Staphylococcus aureus was the most frequent pathogen, with an incidence rate of 4.9 episodes of CR-BSIs per 1,000 catheter/days. Based on logistic regression, the independent risk factors were: colonization on the insertion site =200 colony forming units (CFU/20 cm² (p=0.03; odds ratio (OR =6.89 and catheter tip (p=0.01; OR=7.95. The CR-BSI rate was high; it was mainly associated with S. aureus, and skin colonization at the insertion site and on the catheter tip were important risk factors for CR-BSI.
Full Text Available BACKGROUND: National statistics in developing countries are likely to underestimate deaths due to bacterial infections. Here, we calculated mortality associated with community-acquired bacteremia (CAB in a developing country using routinely available databases. METHODS/PRINCIPAL FINDINGS: Information was obtained from the microbiology and hospital database of 10 provincial hospitals in northeast Thailand, and compared with the national death registry from the Ministry of Interior, Thailand for the period between 2004 and 2010. CAB was defined in patients who had pathogenic organisms isolated from blood taken within 2 days of hospital admission without a prior inpatient episode in the preceding 30 days. A total of 15,251 CAB patients identified, of which 5,722 (37.5% died within 30 days of admission. The incidence rate of CAB between 2004 and 2010 increased from 16.7 to 38.1 per 100,000 people per year, and the mortality rate associated with CAB increased from 6.9 to 13.7 per 100,000 people per year. In 2010, the mortality rate associated with CAB was lower than that from respiratory tract infection, but higher than HIV disease or tuberculosis. The most common causes of CAB were Escherichia coli (23.1%, Burkholderia pseudomallei (19.3%, and Staphylococcus aureus (8.2%. There was an increase in the proportion of Extended-Spectrum Beta-Lactamases (ESBL producing E. coli and Klebsiella pneumoniae over time. CONCLUSIONS: This study has demonstrated that national statistics on causes of death in developing countries could be improved by integrating information from readily available databases. CAB is neglected as an important cause of death, and specific prevention and intervention is urgently required to reduce its incidence and mortality.
McCrea, Keith R.; Ward, Robert S.
Removal of several drug-resistant bacteria from blood by affinity adsorption onto a heparin-functional media is reported. Heparin is a chemical analogue of heparan sulfate (HS) proteoglycans, found on transmembrane proteins of endothelial cells. Many blood-borne human pathogens, including bacteria, viruses, parasites, and fungi have been reported to target HS as an initial step in their pathogenesis. Here, we demonstrate the binding and removal of Methicillin-resistant Staphylococcus aureus (MRSA), Extended-Spectrum Betalactamase Klebsiella pneumoniae (ESBL), and two Carbapenem-resistant Enterobacteriaceae (both CRE Escherichia coli and CRE K. pneumoniae) using 300 μm polyethylene beads surface modified with end-point-attached heparin. Depending on the specific bacteria, the amount removed ranged between 39% (ESBL) and 99.9% (CRE). The total amount of bacteria adsorbed ranged between 2.8 × 105 and 8.6 × 105 colony forming units (CFU) per gram of adsorption media. Based on a polymicrobial challenge which showed no competitive binding, MRSA and CRE apparently utilize different binding sequences on the immobilized heparin ligand. Since the total circulating bacterial load during bacteremia seldom exceeds 5 × 105 CFUs, it appears possible to significantly reduce bacterial concentration in infected patients by multi-pass recirculation of their blood through a small extracorporeal affinity filter containing the heparin-functional adsorption media. This 'dialysis-like therapy' is expected to improve patient outcomes and reduce the cost of care, particularly when there are no anti-infective drugs available to treat the infection.
Fatma Deniz Aygun
Full Text Available Bacillus cereus can cause serious, life-threatening, systemic infections in immunocompromised patients. The ability of microorganism to form biofilm on biomedical devices can be responsible for catheter-related bloodstream infections. Other manifestations of severe disease are meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections. The most common feature in true bacteremia caused by Bacillus is the presence of an intravascular catheter. Herein, we report a case of catheter-related bacteremia caused by B. cereus in a patient with propionic acidemia.
Aygun, Fatma Deniz; Aygun, Fatih; Cam, Halit
Bacillus cereus can cause serious, life-threatening, systemic infections in immunocompromised patients. The ability of microorganism to form biofilm on biomedical devices can be responsible for catheter-related bloodstream infections. Other manifestations of severe disease are meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections. The most common feature in true bacteremia caused by Bacillus is the presence of an intravascular catheter. Herein, we report a case of catheter-related bacteremia caused by B. cereus in a patient with propionic acidemia.
S M Bhatawadekar
Full Text Available Brevundimonas vesicularis has rarely been isolated from clinical specimens. We report here a case of B. vesicularis bacteremia in a female infant who presented with fever, vomiting and altered sensorium. USG abdomen showed mild hepatomegaly, moderate ascitis with bilateral mild basal pleural effusion. Blood culture was processed by BACTEC BD. Isolate was identified as B. vesicularis, by API ID 32 GN automated system. We have come across only one report of neonatal sepsis caused by B. vesicularis from India. To the best of our knowledge, this is one of the rare case reports of B. vesicularis bacteremia in a female infant.
Full Text Available Bacteremia is currently one of the infections with the highest mortality in hospitals . Acinetobacter lwoffii and Acinetobacter baumannii are gram-negative bacteria and both represent opportunistic pathogens. In certain cases, the management can be challenging since these organisms can be highly resistant to antimicrobial agents. Clinical illnesses associated with Acinetobacter include pneumonia, meningitis, peritonitis, endocarditis and infections of the urinary tract and skin . Acinetobacter bacteremia represents a serious and ever increasing problem because of the high associated morbidity and mortality.
Hrishikesh S Kulkarni
Full Text Available Lactobacillus species is a known commensal of the mouth, gastrointestinal, and genitourinary tract. However, its isolation on blood cultures is often overlooked and attributed to bench contamination. We present a case of a 58-year-old immunocompetent male who initially presented with altered mental status, but developed sepsis from Lactobacillus bacteremia during his hospital course, while on mechanical ventilation. He was found to have ischemic colitis on colonoscopy. His condition improved with antibiotics and supportive management. Using this example of ischemic colitis, we stress that in the right clinical setting, Lactobacillus bacteremia is a harbinger for a serious underlying pathology and should not be ignored.
Kwon, Hee Jin; Yoo, Kwai Han; Kim, In Young; Lee, Seulkee; Jang, Hye Ryoun; Kwon, Ghee Young
Megalocytic interstitial nephritis is a rare form of kidney disease caused by chronic inflammation. We report a case of megalocytic interstitial nephritis occurring in a 45-yrold woman who presented with oliguric acute kidney injury and acute pyelonephritis accompanied by Escherichia coli bacteremia. Her renal function was not recovered despite adequate duration of susceptible antibiotic treatment, accompanied by negative conversion of bacteremia and bacteriuria. Kidney biopsy revealed an infiltration of numerous histiocytes without Michaelis-Gutmann bodies. The patient's renal function was markedly improved after short-term treatment with high-dose steroid.
Andersen, Paal Skytt; Pedersen, Jacob Krabbe; Fode, Peder;
Background. Nasal carriage is a major risk factor for Staphylococcus aureus infection. Approximately, one-quarter of adults carry S. aureus. However, the role of host genetics on S. aureus nasal carriage is unknown. Methods. Nasal swabs were obtained from a national cohort of middle-aged and elde......Background. Nasal carriage is a major risk factor for Staphylococcus aureus infection. Approximately, one-quarter of adults carry S. aureus. However, the role of host genetics on S. aureus nasal carriage is unknown. Methods. Nasal swabs were obtained from a national cohort of middle.......4%-34.5%), and opposite sex (21.4%; 95% CI, 12.0%-33.4%) dizygotic twins. Despite shared childhoods, only 1 of 617 pairs was concordant with respect to lineage. Although heritability increased for S. aureus and lineage persistency, no significant heritability was detected. Conclusion. In this study, host genetic factors...
Espinosa-Gongora, Carmen; Larsen, Niels; Schonning, Kristian;
pathogen in animal carriers. The aim of this study was to determine whether the nasal microbiome of pig S. aureus carriers differs from that of non-carriers. The V3-V5 region of the 16S rRNA gene was sequenced from nasal swabs of 44 S. aureus carriers and 56 non-carriers using the 454 GS FLX titanium...... microbiome of pigs that are not colonized with S. aureus harbours several species/taxa that are significantly less abundant in pig carriers, suggesting that the nasal microbiota may play a role in the individual predisposition to S. aureus nasal carriage in pigs. Further research is warranted to isolate...
In Escherichia coli, regulatory inactivation of the replication initiator DnaA occurs after initiation as a result of hydrolysis of bound ATP to ADP, but it has been unknown how DnaA is controlled to coordinate cell growth and chromosomal replication in Gram-positive bacteria such as Staphylococcus aureus. This study examined the roles of ATP binding and its hydrolysis in the regulation of the S. aureus DnaA activity. In vitro, S. aureus DnaA melted S. aureus oriC in the presence of ATP but n...
Full Text Available Linezolid is the only antibiotic available as an oral formulation for resistant staphylococcal infections. It is effective in skin and soft tissue infections, nosocomial pneumonias including VAP, infective endocarditis and MRSA meningitis. It is also effective in the eradication of both nasal and throat colonization of MRSA. Its high bioavailability and post antibiotic effect, ease of switching to oral therapy during its use and the fact that it can be used in patients of all ages, also in patients with liver disease and poor kidney function and its increased effectiveness over glycopeptides makes this drug a precious drug in the treatment of resistant staphylococcal infections. Linezolid resistance in staphylococcus is defined as a linezolid MIC of and #8805;8 mg/L. Reported Linezolid resistance in India and elsewhere is 2-20%. There is clonal dissemination of Linezolid Resistant Staphylococcus aureus (LRSA within or across health care settings which demands continuous surveillance to determine the emergent risk of resistance strains and to establish guidelines for appropriate use. Clinical laboratories should confirm any LRSA preferably by a second method, prior to using linezolid for serious infections. Effective surveillance, more judicious use of this antibiotic, avoiding linezolid usage for empiric therapy in hospital acquired staphylococcus infections, optimization of the pharmacological parameters of the antibiotics in specific clinical situation, decreasing bacterial load by timely surgical debridement or drainage of collections, use of combination therapies would prevent the emergence of resistance to linezolid in staphylococcus aureus. [Int J Res Med Sci 2014; 2(4.000: 1253-1256
Christopher F. Schuster
Full Text Available Toxin-antitoxin (TA systems are small genetic elements found in the majority of prokaryotes. They encode toxin proteins that interfere with vital cellular functions and are counteracted by antitoxins. Dependent on the chemical nature of the antitoxins (protein or RNA and how they control the activity of the toxin, TA systems are currently divided into six different types. Genes comprising the TA types I, II and III have been identified in Staphylococcus aureus. MazF, the toxin of the mazEF locus is a sequence-specific RNase that cleaves a number of transcripts, including those encoding pathogenicity factors. Two yefM-yoeB paralogs represent two independent, but auto-regulated TA systems that give rise to ribosome-dependent RNases. In addition, omega/epsilon/zeta constitutes a tripartite TA system that supposedly plays a role in the stabilization of resistance factors. The SprA1/SprA1AS and SprF1/SprG1 systems are post-transcriptionally regulated by RNA antitoxins and encode small membrane damaging proteins. TA systems controlled by interaction between toxin protein and antitoxin RNA have been identified in S. aureus in silico, but not yet experimentally proven. A closer inspection of possible links between TA systems and S. aureus pathophysiology will reveal, if these genetic loci may represent druggable targets. The modification of a staphylococcal TA toxin to a cyclopeptide antibiotic highlights the potential of TA systems as rather untapped sources of drug discovery.
Schuster, Christopher F; Bertram, Ralph
Toxin-antitoxin (TA) systems are small genetic elements found in the majority of prokaryotes. They encode toxin proteins that interfere with vital cellular functions and are counteracted by antitoxins. Dependent on the chemical nature of the antitoxins (protein or RNA) and how they control the activity of the toxin, TA systems are currently divided into six different types. Genes comprising the TA types I, II and III have been identified in Staphylococcus aureus. MazF, the toxin of the mazEF locus is a sequence-specific RNase that cleaves a number of transcripts, including those encoding pathogenicity factors. Two yefM-yoeB paralogs represent two independent, but auto-regulated TA systems that give rise to ribosome-dependent RNases. In addition, omega/epsilon/zeta constitutes a tripartite TA system that supposedly plays a role in the stabilization of resistance factors. The SprA1/SprA1AS and SprF1/SprG1 systems are post-transcriptionally regulated by RNA antitoxins and encode small membrane damaging proteins. TA systems controlled by interaction between toxin protein and antitoxin RNA have been identified in S. aureus in silico, but not yet experimentally proven. A closer inspection of possible links between TA systems and S. aureus pathophysiology will reveal, if these genetic loci may represent druggable targets. The modification of a staphylococcal TA toxin to a cyclopeptide antibiotic highlights the potential of TA systems as rather untapped sources of drug discovery.
Roberto Rheingantz da Cunha Filho
Full Text Available Descreve-se caso de líquen aureus em paciente do sexo feminino, com 23 anos de idade que apresentava há dois anos lesão dolorosa, purpúrica, acastanhada tendendo por semelhante a cor de ferrugem e de aspecto liquenóide no antebraço. O exame anatomopatológico revelou denso infiltrado linfo-histiocitário na derme superior papilar, com extravasamento de hemácias. O líquen aureus é relativamente raro, sendo ainda mais raro o sintoma de dor.A case is described of lichen aureus in a 23 year old female with a 2-year history of painful, purpuric, rust-coloured to tan, lichenous lesion on forearm. A biopsy specimen demonstrated a dense lymphohistiocytic infiltrate in the upper dermis, with extravasation of red cells. The "algesiogenic" lichen aureus is a very rare dermatosis.
Rehm, Susan J; Tice, Alan
The evolution of methicillin-resistant and vancomycin-resistant Staphylococcus aureus has demanded serious review of antimicrobial use and development of new agents and revised approaches to prevent and overcome drug resistance. Depending on local conditions and patient risk factors, empirical therapy of suspected S. aureus infection may require coverage of drug-resistant organisms with newer agents and novel antibiotic combinations. The question of treatment with inappropriate antibiotics raises grave concerns with regard to methicillin-resistant S. aureus selection, overgrowth, and increased virulence. Several strategies to reduce the nosocomial burden of resistance are suggested, including shortened hospital stays and outpatient parenteral antimicrobial therapy of the most serious infections.
Popa, ER; Tervaert, JWC
To date, in the investigation of the role of S. aureus in WG, we face a paradoxical situation. On the one hand, clinical results obtained from treatment of WG patients with co-trimoxazole and studies assessing the impact of S. aureus on disease relapses strongly suggest that this bacterium contribut
Liu, Cindy M; Price, Lance B; Hungate, Bruce A;
The human microbiome can play a key role in host susceptibility to pathogens, including in the nasal cavity, a site favored by Staphylococcus aureus. However, what determines our resident nasal microbiota-the host or the environment-and can interactions among nasal bacteria determine S. aureus co...
Full Text Available Background: Bloodstream infection (BSI and bacteremias due to Enterococcus spp. are increasing worldwide with the current need to understand its causes among hospitalized trauma patients. Hence, the study was conducted. Methodology: A 3-year retrospective laboratory cum clinical based study was performed at a level I trauma center in India. Patients with health care associated enterococcal bacteremia were identified using the hospital database, their episodes of BSI/bacteremia calculated and their clinical records and treatment were noted. Results: A total of 104 nonrepetitive Enterococcus spp. was isolated of which Enterococcus faecium was the most common (52%. High-level resistance to gentamicin high-level aminoglycoside resistance was seen in all the Enterococcus spp. causing bacteremia, whereas a low resistance to vancomycin and teichoplanin was observed. Overall mortality was more in patients infected with vancomycin-resistant Enterococcus (5/11, 46% compared to those with vancomycin sensitive Enterococcus (9/93, 10%; though no significant association of mortality with Enterococcus spp. bacteremia ( P > 0.05 was seen. The rate of bacteremia due to Enterococcus spp. was 25.4 episodes/1,000 admissions (104/4,094 during the study period. Conclusion: Enterococcal bacteremia is much prevalent in trauma care facilities. Here, a microbiologist can act as a sentinel and help in preventing such infections.
Ku, Nam Su; Kim, Hye-Won; Oh, Hyung Jung; Kim, Yong Chan; Kim, Min Hyung; Song, Je Eun; Oh, Dong Hyun; Ahn, Jin Young; Kim, Sun Bean; Jeong, Su Jin; Han, Sang Hoon; Kim, Chang Oh; Song, Young Goo; Kim, June Myung; Choi, Jun Yong
Red blood cell distribution width (RDW) is known to be a predictor of severe morbidity and mortality in some chronic diseases such as congestive heart failure. However, to our knowledge, little is known about RDW as a predictor of mortality in patients with Gram-negative bacteremia, a major nosocomial cause of intra-abdominal infections, urinary tract infections, and primary bacteremia. Therefore, we investigated whether RDW is an independent predictor of mortality in patients with Gram-negative bacteremia. Clinical characteristics, laboratory parameters, and outcomes of 161 patients with Gram-negative bacteremia from November 2010 to March 2011 diagnosed at Severance Hospital, Yonsei University College of Medicine, Seoul, Korea, were retrospectively analyzed. The main outcome measure was 28-day all-cause mortality. The 28-day mortality rate was significantly higher in the increased RDW group compared with the normal RDW group (P blood cell distribution width at the onset of bacteremia was an independent predictor of mortality in patients with Gram-negative bacteremia. Also, 72-h RDW could be a predictor for all-cause mortality in patients with Gram-negative bacteremia.
Helena Engel VELANO
Full Text Available O Staphylococcus aureus faz parte da microbiota da pele, mucosas e nasofaringe de várias espécies animais, incluindo o homem, mas também está associado a enfermidades como abscessos, bacteremias, endocardites e osteomielites, além de se mostrar resistente a múltiplas drogas. Este trabalho foi realizado com a finalidade de avaliar o efeito do gás ozônio, dissolvido em água, sobre o S. aureus. Foram preparadas suspensões de S. aureus, com concentrações variando de 10(6 a 10(16 microrganismos/ml. De cada suspensão recém-preparada foi retirado 1 ml e adicionado a 99 ml de água destilada estéril (com ou sem prévia ozonização, em um reator de cristal. Foram preparadas diluições seriadas (1/10 das suspensões testadas e inoculado 0,1 ml de cada suspensão em Tryptic Soy Agar, incubadas a 37ºC por 24 h, quando então se procedeu à contagem das UFC. Os resultados obtidos mostraram que o tempo máximo para a inativação total das bactérias tratadas com água previamente ozonizada (0,6 mg/ml foi de 525" e, para a água não previamente ozonizada, foi de 2345", indicando um efeito antibacteriano mais rápido da água previamente ozonizada, frente ao S. aureus.Staphylococcus aureus belongs to the normal flora of the skin, mucosa and nasopharynx of several animal species, including man, but it is also associated to illnesses such as abscesses, bacteremia, endocarditis and osteomyelitis, besides showing resistance to multiple drugs. The purpose of this paper was to evaluate the disinfecting ability of ozone when dissolved in water. Suspensions of Staphylococcus aureus with concentrations varying from 10(6 to 10(16 microorganisms/ml were prepared. One milliliter of each recently prepared suspension was added to 99 ml of distilled water (with or without previous ozonization contained in a crystal reactor. Aliquots of 0.1 ml of this new suspension were taken at various time intervals and, then, serially diluted and inoculated on
Hizawa, Kazuoki; Nagata, Yuko; Taniguchi, Masahiko; Nakamori, Mari; Matsumoto, Takayuki; Iida, Mitsuo
We describe a case of 36-year-old Japanese man with Crohn's disease, complicated by Bacillus cereus bacteremia on maintenance azathioprine therapy. Although anti-microbial agents were ineffective, the patient became well immediately after a partial resection of the ileum with multiple severe stenosis.
Garcia, I; Fainstein, V; McLaughlin, P
After placement of an Ommaya reservoir, meningitis and bacteremia due to Bacillus cereus occurred in a patient with stage IV lymphoblastic lymphoma and meningeal involvement. Bacillus species have been implicated as meningeal pathogens after lumbar punctures. These organisms have become an important cause of severe infection, especially in immunologically compromised patients.
Asim Ahmed Kichloo
Full Text Available Erysipelothrix rhusiopathiae, a pleomorphic gram-positive bacillus, is found widely in nature or as a commensal pathogen. It infects domestic animals such as swine, which may be the major reservoir of the organism. E. rhusiopathiae is primarily an occupational illness; 89% of the cases are linked to high-risk epidemiological situations. Humans that are infected by this bacillus typically present with one or a combination of the following symptoms: localized skin lesion (erysipeloid, diffuse cutaneous eruptions with systemic symptoms, or bacteremia, which is often followed by endocarditis. We report a case of E. rhusiopathiae bacteremia that was present without severe clinical illness such as endocarditis, arthritis, or skin lesions. The patient was a 64-year-old male with a complicated past medical history including subclinical alcoholic liver disease. Penicillin-G therapy completely resolved the patients bacteremia. The case presented has exceptional clinical merit due to 2 key factors: the patient does not fit the occupational demographic typically affected by this bacterium, and the patient presented with subclinical septicemia, which has a high correlation with fatal endocarditis. This case brings a new prospective to E. rhusiopathiae bacteremia.
Tobe, TJM; Franssen, CFM; Zijlstra, JG; de Jong, PE; Stegeman, CA
The hemolytic uremic syndrome (HUS) is known to have several causes, including infectious diseases, drugs, pregnancy, and malignant disease. We report a patient who developed acute renal failure attributable to HUS in the course of Capnocytophaga canimorsus bacteremia. Acute tubular necrosis as well
Basaglia, G.; Carretto, E.; Barbarini, D.; Moras, L.; Scalone, S.; Marone, P.; De Paoli, P.
We report on the first case of a catheter-related recurrent bacteremia caused by Kocuria kristinae, a gram-positive microorganism belonging to the family Micrococcaceae, in a 51-year-old woman with ovarian cancer. This unusual pathogen may cause opportunistic infections in patients with severe underlying diseases. PMID:11773142
Boel, Jonas Bredtoft; Søgaard, Mette; Andreasen, Viggo;
treatment. We categorized 2,008 adult patients diagnosed with bacteremia between 2010 and 2012 according to whether they received cephalosporins or fluoroquinolones (old regimen) or not (new regimen). We used administrative data to extract individual level data on mortality, readmission, and appropriateness...
Srifuengfung, Somporn; Tharavichitkul, Prasit; Pumprueg, Satchana; Tribuddharat, Chanwit
Roseomonas is a pink-pigmented, non-fermentative, gram-negative coccobacillus bacterium. Human infections caused by Roseomonas are very rare. We report the first case of bacteremia associated with Roseomonas gilardii subsp rosea in Thailand. The bacterium was isolated from blood culture and identified by cellular morphology, characteristics of colonies on blood agar, extensive biochemical tests and 16S ribosomal DNA sequencing.
von Kietzell, M; Richter, H; Bruderer, T; Goldenberger, D; Emonet, S; Strahm, C
Neisseria cinerea is a human commensal. The first known case of meningitis and bacteremia due to Neisseria cinerea following percutaneous glycerol instillation of the trigeminal ganglion is reported. Conventional phenotypic methods and complete 16S RNA gene sequencing accurately identified the pathogen. Difficulties in differentiation from pathogenic neisseriae are discussed.
von Kietzell, M.; Richter, H.; Bruderer, T.; Goldenberger, D.; Emonet, S; Strahm, C.
Neisseria cinerea is a human commensal. The first known case of meningitis and bacteremia due to Neisseria cinerea following percutaneous glycerol instillation of the trigeminal ganglion is reported. Conventional phenotypic methods and complete 16S RNA gene sequencing accurately identified the pathogen. Difficulties in differentiation from pathogenic neisseriae are discussed.
Kordjian, Hayarpi H; Schultz, Joyce D J H; Rosenvinge, Flemming Schønning
We present a case of Eggerthia catenaformis bacteremia originating from a dental abscess and imitating necrotizing fasciitis in a previously healthy adult. The isolates were easily identified by MALDI-TOF MS. The clinical course, surgical and antibiotic treatment as well as the successful outcome...
Forner, Lone; Larsen, Tove; Kilian, Mogens
higher in periodontitis than in gingivitis patients and healthy control individuals. In periodontitis patients, the magnitude of bacteremia was associated with gingival index, plaque index and number of sites with bleeding on probing, but not with probing pocket depth measurements. PRACTICAL IMPLICATIONS...
Larsen, F.L.; Kilian, Mogens; Holmstrup, P.
higher in periodontitis than in gingivitis patients and healthy control individuals. In periodontitis patients, the magnitude of bacteremia was associated with gingival index, plaque index and number of sites with bleeding on probing, but not with probing pocket depth measurements. Practical implications...
Cuno, SPMU; Heesen, GJM; Arends, JP; Kimpen, JLL; van Houten, M.A.
Background, Gram-negative bacteremia in children, a major cause of morbidity and mortality, may in part be induced by intensive treatment procedures and nonspecific use of antibiotics. Our primary objective was to study the causal relationship between the use of vancomycin and Gram-negative bacterem
Full Text Available We describe a case of Bacteroides fragilis bacteremia associated with paraspinal and psoas abscesses in the United States. Resistance to b-lactam/b-lactamase inhibitors, carbapenems, and metronidazole was encountered despite having a recent travel history to India as the only possible risk factor for multidrug resistance. Microbiological cure was achieved with linezolid, moxifloxacin, and cefoxitin.
Skov Dalgaard, Lars; Nørgaard, Mette; Povlsen, Johan Vestergaard;
BACKGROUND: Bacterial infections are common complications in kidney transplant recipients (KTRs). Little is known about incidence rates of bacteremia and fungemia (BAF) in KTRs. METHODS: In this population-based cohort study, we used medical and administrative registries to identify episodes of BAF...
Lee, Chung-Hsun; Lee, Ching-Chi; Hsieh, Chih-Chia; Hong, Ming-Yuan; Chi, Chih-Hsien
Enterobacteriaceae is a leading pathogen of community-onset bacteremia. This study aims to establish a predictive scoring algorithm to identify adults with community-onset Enterobacteriaceae bacteremia who are at risk for abscesses. Of the total 1262 adults, 152 (12.0%) with abscess occurrence were noted. The 6 risk factors significantly associated with abscess occurrence-liver cirrhosis, diabetes mellitus, thrombocytopenia and high C-reactive protein (>100 mg/L) at bacteremic onset, delayed defervescence, and bacteremia-causing Klebsiella pneumoniae-were each assigned +1 point to form the scoring algorithm. In contrast, the elderly, fatal comorbidity (McCabe classification), and bacteremia-causing Escherichia coli were each assigned -1 point, owing to their negative associations with abscess occurrence. Using the proposed scoring algorithm, a cut-off value of +1 yielded a high sensitivity (85.5%) and an acceptable specificity (60.4%). Although the proposed predictive model needs further validation, this simple scoring algorithm may be useful for the early identification of abscesses by clinicians.
Tugba Arslan Gulen
Conclusion: Our results suggest that the occurrence of MDR A.baumannii bacteremia was related with the usage of the wide spectrum antibiotics, and mortality rates were increased in patients that high SAPS II scores, long term hospitalization. Infection control procedures and limited antibiotic usage are very important for prevent nosocomial infections.
Zorman, Julie K; Esser, Mark; Raedler, Michael; Kreiswirth, Barry N; Ala'Aldeen, Dlawer A A; Kartsonis, Nicholas; Smugar, Steven S; Anderson, Annaliesa S; McNeely, Tessie; Arduino, Jean Marie
Staphylococcus aureus is a well-recognized, clinically important cause of nosocomial infections, and as such, a vaccine to prevent S. aureus infections would be an important achievement. A Phase IIB/III study of V710, a vaccine containing iron-regulated surface determinant B (IsdB), demonstrated significant sero-conversion rates in cardiovascular surgery patients following a single pre-surgery immunization. However, the vaccine was not efficacious in preventing bacteremia or deep sternal wound infection post-surgery, thus raising the possibility that IsdB might not be available for immune recognition during infection. The purpose of the work described herein was to evaluate and quantify the naturally occurring anti-IsdB levels at baseline and over time during infection, to understand whether IsdB is expressed during a S. aureus infection in hospitalized non-vaccinated patients. We evaluated baseline and follow-up titers in 3 populations: (1) healthy subjects, (2) hospitalized patients with non-S. aureus infections, and (3) hospitalized patients with S. aureus infections. Baseline anti-IsdB levels generally overlapped between the 3 groups, but were highly variable within each group. In healthy subjects, baseline and follow-up levels were highly correlated (Spearman's rho = 0.93), and the geometric mean fold-rise (GMFR) in anti-IsdB levels between study entry and last value was 0.9-fold (95% confidence interval (CI): 0.8 to 1.0 ; p = 0.09), showing no trend over time. The convalescent GMFR in anti-IsdB levels from baseline was 1.7-fold (95% CI: 1.3 to 2.2, p = 0.0008) during S. aureus infection, significantly different from the 1.0-fold GMFR (95% CI: 0.9-1.2, p = 0.60) in non-S. aureus infection, p = 0.005. Additionally, S. aureus isolates (51) obtained from the hospitalized patient group expressed the IsdB protein in vitro. Collectively, these data suggest that IsdB expression levels rise substantially following infection with S. aureus, but not with other pathogens
Gubbels, Sophie; Nielsen, Jens; Voldstedlund, Marianne; Kristensen, Brian; Schønheyder, Henrik C; Ellermann-Eriksen, Svend; Engberg, Jørgen H; Møller, Jens K; Østergaard, Christian; Mølbak, Kåre
BACKGROUND In 2015, Denmark launched an automated surveillance system for hospital-acquired infections, the Hospital-Acquired Infections Database (HAIBA). OBJECTIVE To describe the algorithm used in HAIBA, to determine its concordance with point prevalence surveys (PPSs), and to present trends for hospital-acquired bacteremia SETTING Private and public hospitals in Denmark METHODS A hospital-acquired bacteremia case was defined as at least 1 positive blood culture with at least 1 pathogen (bacterium or fungus) taken between 48 hours after admission and 48 hours after discharge, using the Danish Microbiology Database and the Danish National Patient Registry. PPSs performed in 2012 and 2013 were used for comparison. RESULTS National trends showed an increase in HA bacteremia cases between 2010 and 2014. Incidence was higher for men than women (9.6 vs 5.4 per 10,000 risk days) and was highest for those aged 61-80 years (9.5 per 10,000 risk days). The median daily prevalence was 3.1% (range, 2.1%-4.7%). Regional incidence varied from 6.1 to 8.1 per 10,000 risk days. The microorganisms identified were typical for HA bacteremia. Comparison of HAIBA with PPS showed a sensitivity of 36% and a specificity of 99%. HAIBA was less sensitive for patients in hematology departments and intensive care units. Excluding these departments improved the sensitivity of HAIBA to 44%. CONCLUSIONS Although the estimated sensitivity of HAIBA compared with PPS is low, a PPS is not a gold standard. Given the many advantages of automated surveillance, HAIBA allows monitoring of HA bacteremia across the healthcare system, supports prioritizing preventive measures, and holds promise for evaluating interventions. Infect Control Hosp Epidemiol 2017;1-8.
Full Text Available Abstract Background previous studies have established that bacterial blood concentration is related with clinical outcome. Time to positivity of blood cultures (TTP has relationship with bacterial blood concentration and could be related with prognosis. As there is scarce information about the usefulness of TTP, we study the relationship of TTP with clinical parameters in patients with Streptococcus pneumoniae bacteremia. Methods TTP of all cases of Streptococcus pneumoniae bacteremia, detected between January 1995 and December 2004 using the BacT/Alert automated blood culture system in a teaching community hospital was analyzed. When multiple cultures were positive only the shortest TTP was selected for the analysis. Results in the study period 105 patients with Streptococcus pneumoniae bacteremia were detected. Median TTP was 14.1 hours (range 1.2 h to 127 h. Immunosuppressed patients (n = 5, patients with confusion (n = 19, severe sepsis or shock at the time of blood culture extraction (n = 12, those with a diagnosis of meningitis (n = 7 and those admitted to the ICU (n = 14 had lower TTP. Patients with TTP in the first quartile were more frequently hospitalized, admitted to the ICU, had meningitis, a non-pneumonic origin of the bacteremia, and a higher number of positive blood cultures than patients with TTP in the fourth quartile. None of the patients with TTP in the 90th decile had any of these factors associated with shorter TTP, and eight out of ten patients with TTP in the 10th decile had at least one of these factors. The number of positive blood cultures had an inverse correlation with TTP, suggesting a relationship of TTP with bacterial blood concentration. Conclusion Our data support the relationship of TTP with several clinical parameters in patients with Streptococcus pneumoniae bacteremia, and its potential usefulness as a surrogate marker of outcome.
Kobayashi, Scott D; Malachowa, Natalia; DeLeo, Frank R
Staphylococcus aureus causes many types of human infections and syndromes-most notably skin and soft tissue infections. Abscesses are a frequent manifestation of S. aureus skin and soft tissue infections and are formed, in part, to contain the nidus of infection. Polymorphonuclear leukocytes (neutrophils) are the primary cellular host defense against S. aureus infections and a major component of S. aureus abscesses. These host cells contain and produce many antimicrobial agents that are effective at killing bacteria, but can also cause non-specific damage to host tissues and contribute to the formation of abscesses. By comparison, S. aureus produces several molecules that also contribute to the formation of abscesses. Such molecules include those that recruit neutrophils, cause host cell lysis, and are involved in the formation of the fibrin capsule surrounding the abscess. Herein, we review our current knowledge of the mechanisms and processes underlying the formation of S. aureus abscesses, including the involvement of polymorphonuclear leukocytes, and provide a brief overview of therapeutic approaches.
Full Text Available Staphylococcus aureus frequently invades the human bloodstream, leading to life threatening bacteremia and often secondary foci of infection. Failure of antibiotic therapy to eradicate infection is frequently described; in some cases associated with altered S. aureus antimicrobial resistance or the small colony variant (SCV phenotype. Newer antimicrobials, such as linezolid, remain the last available therapy for some patients with multi-resistant S. aureus infections. Using comparative and functional genomics we investigated the molecular determinants of resistance and SCV formation in sequential S. aureus isolates from a patient who had a persistent and recurrent S. aureus infection, after failed therapy with multiple antimicrobials, including linezolid. Two point mutations in key staphylococcal genes dramatically affected clinical behaviour of the bacterium, altering virulence and antimicrobial resistance. Most strikingly, a single nucleotide substitution in relA (SACOL1689 reduced RelA hydrolase activity and caused accumulation of the intracellular signalling molecule guanosine 3', 5'-bis(diphosphate (ppGpp and permanent activation of the stringent response, which has not previously been reported in S. aureus. Using the clinical isolate and a defined mutant with an identical relA mutation, we demonstrate for the first time the impact of an active stringent response in S. aureus, which was associated with reduced growth, and attenuated virulence in the Galleria mellonella model. In addition, a mutation in rlmN (SACOL1230, encoding a ribosomal methyltransferase that methylates 23S rRNA at position A2503, caused a reduction in linezolid susceptibility. These results reinforce the exquisite adaptability of S. aureus and show how subtle molecular changes cause major alterations in bacterial behaviour, as well as highlighting potential weaknesses of current antibiotic treatment regimens.
Value of soluble TREM-1, procalcitonin, and C-reactive protein serum levels as biomarkers for detecting bacteremia among sepsis patients with new fever in intensive care units: a prospective cohort study
Full Text Available Abstract Background The purpose of this study was to explore the diagnostic value of soluble triggering receptor expressed on myeloid cells 1 (sTREM-1, procalcitonin (PCT, and C-reactive protein (CRP serum levels for differentiating sepsis from SIRS, identifying new fever caused by bacteremia, and assessing prognosis when new fever occurred. Methods We enrolled 144 intensive care unit (ICU patients: 60 with systemic inflammatory response syndrome (SIRS and 84 with sepsis complicated by new fever at more than 48 h after ICU admission. Serum sTREM-1, PCT, and CRP levels were measured on the day of admission and at the occurrence of new fever (>38.3°C during hospitalization. Based on the blood culture results, the patients were divided into a blood culture-positive bacteremia group (33 patients and blood culture-negative group (51 patients. Based on 28-day survival, all patients, both blood culture-positive and -negative, were further divided into survivor and nonsurvivor groups. Results On ICU day 1, the sepsis group had higher serum sTREM-1, PCT, and CRP levels compared with the SIRS group (P P Conclusions Serum sTREM-1, PCT, and CRP levels each have a role in the early diagnosis of sepsis. Serum sTREM-1, with the highest sensitivity and specificity of all indicators studied, is especially notable. sTREM-1, PCT, and CRP levels are of no use in determining new fever caused by bacteremia in ICU patients, but sTREM-1 levels reflect the prognosis of bacteremia. Trial registration ClinicalTrial.gov identifier NCT01410578
Full Text Available Background: Staphylococcus aureus (S. aureus is one of the major pathogens causing chronic infections. The ability of S. aureus to acquire resistance to a diverse range of antimicrobial compounds results in limited treatment options, particularly in methicillin-resistant S. aureus (MRSA. A mechanism by which S. aureus develops reduced susceptibility to antimicrobials is through the formation of small colony variants (SCVs. Infections by SCVs of S. aureus are an upcoming problem due to difficulties in laboratory diagnosis and resistance to antimicrobial therapy. Methods: A prospective study was performed on 120 patients diagnosed with both type 2 diabetes mellitus and infected diabetic foot ulcers. The study was carried out from July 2012 to December 2013 in Hospital General de Mexico. The samples were cultured in blood agar, mannitol salt agar, and MacConkey agar media, and incubated at 37°C in aerobic conditions. Results: We describe the first known cases of diabetic foot infections caused by MRSA-SCVs in patients diagnosed with type 2 diabetes mellitus and infected diabetic foot ulcers. In all of our cases, the patients had not received any form of gentamicin therapy. Conclusions: The antibiotic therapy commonly used in diabetic patients with infected diabetic foot ulcers fails in the case of MRSA-SCVs because the intracellular location protects S. aureus-SCVs from the host's defenses and also helps them resist antibiotics. The cases studied in this article add to the spectrum of persistent and relapsing infections attributed to MRSA-SCVs and emphasizes that these variants may also play a relevant role in diabetic foot infections.
Cervantes-García, Estrella; García-Gonzalez, Rafael; Reyes-Torres, Angélica; Resendiz-Albor, Aldo Arturo; Salazar-Schettino, Paz María
Background Staphylococcus aureus (S. aureus) is one of the major pathogens causing chronic infections. The ability of S. aureus to acquire resistance to a diverse range of antimicrobial compounds results in limited treatment options, particularly in methicillin-resistant S. aureus (MRSA). A mechanism by which S. aureus develops reduced susceptibility to antimicrobials is through the formation of small colony variants (SCVs). Infections by SCVs of S. aureus are an upcoming problem due to difficulties in laboratory diagnosis and resistance to antimicrobial therapy. Methods A prospective study was performed on 120 patients diagnosed with both type 2 diabetes mellitus and infected diabetic foot ulcers. The study was carried out from July 2012 to December 2013 in Hospital General de Mexico. The samples were cultured in blood agar, mannitol salt agar, and MacConkey agar media, and incubated at 37°C in aerobic conditions. Results We describe the first known cases of diabetic foot infections caused by MRSA-SCVs in patients diagnosed with type 2 diabetes mellitus and infected diabetic foot ulcers. In all of our cases, the patients had not received any form of gentamicin therapy. Conclusions The antibiotic therapy commonly used in diabetic patients with infected diabetic foot ulcers fails in the case of MRSA-SCVs because the intracellular location protects S. aureus-SCVs from the host's defenses and also helps them resist antibiotics. The cases studied in this article add to the spectrum of persistent and relapsing infections attributed to MRSA-SCVs and emphasizes that these variants may also play a relevant role in diabetic foot infections. PMID:25787018
Jelsbak, Lotte; Thomsen, Line Elnif; Ingmer, Hanne;
Staphyloccous aureus is a major human pathogen capable of causing a wide spectrum of infections ranging from superficial wound infections to life-threatening endocarditis and toxic shock syndrome. Essential for S. aureus virulence is a large number of cell-surface-associated proteins and secreted...... proteins. Results from our group have shown that the ClpXP proteolytic complex and the ClpX chaperone play central roles in regulating expression of many of these factors (2;3). By using DNA microarrays to compare transcription of strain 8325-4 (wt) and the isogenic ¿clpX strain during the transition phase...
Full Text Available Staphylococcus aureus (S. aureus osteomyelitis is a significant complication for orthopaedic patients undergoing surgery, particularly with fracture fixation and arthroplasty. Given the difficulty in studying S. aureus infections in human subjects, animal models serve an integral role in exploring the pathogenesis of osteomyelitis, and aid in determining the efficacy of prophylactic and therapeutic treatments. Animal models should mimic the clinical scenarios seen in patients as closely as possible to permit the experimental results to be translated to the corresponding clinical care. To help understand existing animal models of S. aureus, we conducted a systematic search of PubMed and Ovid MEDLINE to identify in vivo animal experiments that have investigated the management of S. aureus osteomyelitis in the context of fractures and metallic implants. In this review, experimental studies are categorised by animal species and are further classified by the setting of the infection. Study methods are summarised and the relevant advantages and disadvantages of each species and model are discussed. While no ideal animal model exists, the understanding of a model’s strengths and limitations should assist clinicians and researchers to appropriately select an animal model to translate the conclusions to the clinical setting.
Lister, Jessica L; Horswill, Alexander R
Staphylococcus aureus is a major cause of nosocomial and community-acquired infections and represents a significant burden on the healthcare system. S. aureus attachment to medical implants and host tissue, and the establishment of a mature biofilm, play an important role in the persistence of chronic infections. The formation of a biofilm, and encasement of cells in a polymer-based matrix, decreases the susceptibility to antimicrobials and immune defenses, making these infections difficult to eradicate. During infection, dispersal of cells from the biofilm can result in spread to secondary sites and worsening of the infection. In this review, we discuss the current understanding of the pathways behind biofilm dispersal in S. aureus, with a focus on enzymatic and newly described broad-spectrum dispersal mechanisms. Additionally, we explore potential applications of dispersal in the treatment of biofilm-mediated infections.
documentation by the physi- cians and nurses who took care of the patients. There was also no clear guidance on ventilator modes such as HFPV and how their...Presence of Bacteremia in Burned Patients Admitted to the Intensive Care Unit Brian K. Hogan, MD,*†‡ Steven E. Wolf, MD,*‡§ Duane R. Hospenthal, MD...criteria’s correlation with bacteremia because bacteremia is not associated with inherent issues of diagnosis as occurs with pneumonia or soft tissue
Møller, Holger Jon; K. Moestrup, Søren; Wejse, Christian
with pneumococcal bacteremia. DESIGN: Observational cohort study. SETTING: Five university hospitals in Denmark. PATIENTS: A total of 133 patients with Streptococcus pneumoniae bacteremia (positive blood culture) and 133 age- and gender-matched controls. INTERVENTIONS: Samples were collected for biochemical......OBJECTIVE: Soluble CD163 (sCD163) is a new macrophage-specific serum marker. This study investigated sCD163 and other markers of macrophage activation (neopterin, ferritin, transcobalamin, and soluble urokinase plasminogen activator receptor [suPAR]) as prognostic factors in patients...... were observed in patients who needed intensive care (hemodialysis, p = .0011; hypotension, p = .0014; mechanical ventilation, p = .0019). Significantly lower levels of sCD163, ferritin, transcobalamin, and suPAR (but not C-reactive protein) were measured in patients > or =75 yrs. In patients
Al-Anazi, K A; AlHashmi, H; Abdalhamid, B; AlSelwi, W; AlSayegh, M; Alzayed, A; Alshibani, Z; AlGarni, A; Al-Ghanem, A; Hassan, H; AlSagheir, A
Roseomonas are pink-pigmented, oxidative, slowly growing, nonfermentative, gram-negative coccobacilli whose identification may require extensive biochemical testing and molecular profiling. Roseomonas infections vary in severity and clinical presentation, and they predominantly occur in immunocompromised and chronically ill patients. The organism is generally susceptible to carbapenems and aminoglycosides, but resistant to most of the cephalosporins and broad-spectrum penicillins. Reported here is a patient with lymphoblastic lymphoma who developed Roseomonas mucosa bacteremia after receiving her hematopoietic stem cell allograft. The bacteremic episode was successfully treated with imipenem and amikacin in addition to removal of the central venous catheter. To our knowledge, this is the first report of Roseomonas bacteremia in a stem cell transplantation recipient.
Lopardo, H; Mastroianni, A; Casimir, L
The presence of Granulicatella spp. in bacteremic episodes of neutropenic patients was recently highlighted whereas Abiotrophia defectiva, was only isolated in cases of infectious endocarditis. The aim of this study is to describe a case of A.defectiva bacteremia in a leukemic and febrile (40 degrees C) neutropenic (200 GB/mm3) boy. A.defectiva was only isolated from one of the two processed blood samples. Although the patient was undergoing an episode of varicela which could have accounted as the possible cause of fever, A. defectiva was considered a significant finding because this species is not part of the commensal skin flora. This case suggests that both A. defectiva and Granulicatella spp. should be regarded as possible causes of bacteremia in immunocompromised patients.
Full Text Available This is to report a case of bacteremia caused by Salmonella typhi in a treated unilateral fungal endogenous endophthalmitis in an 18-year-old male from one of the South Asian countries. Microbiological and molecular investigations were carried out on the eviscerated material and routine blood culture was carried out. Direct examination of eviscerated material revealed the presence of fungal filaments. However, Salmonella typhi was isolated from both specimens, which was confirmed by Polymerase chain reaction targeting the 16SrRNA gene, sequencing, and random amplification of polymorphic DNA showed that they belonged to the same clone. The presence of Salmonella bacteremia in a treated unilateral fungal endophthalmitis, among young adult patients is rare and systemic symptoms should be investigated.
Full Text Available The use of acridine orange stained buffy coat smears was assessed as a rapid screening test for bacteremia in adults. A total of 356 consecutive blood cultures were submitted with simultaneous anticoagulated blood samples, from which a buffy coat smear was prepared and stained with acridine orange (100 mg/L; pH 3.0. Forty-one of 356 blood samples (12% yielded organisms in the blood culture system. Compared to blood culture, the overall sensitivity of acridine orange stained buffy coat smears was 16%, specificity 88%, and positive predictive value 13%. There was no statistically significant difference in performance of the test among patients who had fever greater than 39°C and/or shock. The low sensitivity and specificity of the test makes it unsuitable as a means of rapid screening for adults with suspected bacteremia.
Shamsutdinov, A F; Tiurin, Iu A
Main scientific-research studies regarding protein bacterial toxins of the most widespread bacteria that belong to Staphylococcus spp. genus and in particular the most pathogenic species for humans--Staphylococcus aureus, are analyzed. Structural and biological properties of protein toxins that have received the name of staphylococcus pyrogenic toxins (PTSAg) are presented. Data regarding genetic regulation of secretion and synthesis of these toxins and 3 main regulatory genetic systems (agr--accessory gene regulator, xpr--extracellular protein regulator, sar--staphylococcal accessory regulator) that coordinate synthesis of the most important protein toxins and enzymes for virulence of S. aureus, are presented.
Full Text Available Introduction: Methicillin resistant Staphylococcus aureus (MRSA has emerged as a nosocomial pathogen of major worldwide importance and is an increasingly frequent cause of community-acquired infections. In this study, different risk factors and MRSA resistance pattern were investigated. Methods: In a 24 months period, all of the patients who were confined to bed in the surgery ward were included in the study. Then they were assessed to find out as if they had MRSA infection when hospitalized and once when they were discharged. Almost 48 h after admission, when patients were discharged, social and medical histories were acquired. Acquired samples were examined. Results: During the present study of 475 patients, 108 patients (22.8% had S. aureus. About frequency of antibiotic resistance among collected S. aureus colonies, erythromycin resistance, was the most frequent antibiotic resistance, also resistance to vancomycin was 0.4% that was the least. Only hospitalization duration had statistically significant correlation with antibiotic resistance, also resistance to erythromycin had statistically significant relation with history of surgery and alcohol consumption. Of all 34 MRSA species, 22 (64.7% samples were resistant to erythromycin, 17 (50.0% resistant to cefoxitin, 5 (14.7% resistant to mupirocin, 1 (2.9% resistant to vancomycin and 1 (2.9% resistant to linezolid. Conclusion: The results of the current study show that among hospitalized patients, there is resistance against methicillin. Since based on results of the study there is resistance against oxacillin and erythromycin in most cases, administering appropriate antibiotics have an important role in minimizing the resistance burden among bacterial species.
Full Text Available BACKGROUND: Neonates with bacteremia are at risk of neurologic complications. Relevant information warrants further elucidation. STUDY DESIGN: This was a retrospective cohort study of neonates with bacteremia-related neurologic complications (BNCs in a tertiary-level neonatal intensive care unit (NICU. A systemic chart review was performed conducted to identify clinical characteristics and outcomes. A cohort of related conditions was constructed as the control group. Logistic regression analysis was used to identify independent risk factors for BNC. RESULTS: Of 1037 bacteremia episodes, 36 (3.5% had BNCs. Twenty-four cases of BNCs were related to meningitis, five were presumed meningitis, and seven occurred after septic shock. The most common causative pathogens were Group B streptococcus (41.7% and E. coli (16.7%. The major BNCs consisted of seizures (28, hydrocephalus (20, encephalomalacia (11, cerebral infarction (7, subdural empyema (6, ventriculitis (8, and abscess (4. Eight (22.8% neonates died and six (16.7% were discharged in critical condition when the family withdrew life-sustaining treatment. Among the 22 survivors, eight had neurologic sequelae upon discharge. After multivariate logistic regression analysis, neonates with meningitis caused by Group B streptococcus (adjusted odds ratio [OR]: 8.90, 95% confidence interval [CI]: 2.20-36.08; p = 0.002 and combined meningitis and septic shock (OR, 5.94; 95% CI: 1.53-23.15; p = 0.010 were independently associated with BNCs. CONCLUSIONS: Neonates with bacteremia-related neurologic complications are associated with adverse outcomes or sequelae. Better strategies aimed at early detection and reducing the emergence of neurologic complications and aggressive treatment of Group B streptococcus sepsis are needed in neonates with meningitis and septic shock.
Benusic, Michael A; Press, Natasha M; Linda MN Hoang; Romney, Marc G.
Bacillus cereus is a ubiquitous spore-forming organism that is infrequently implicated in extraintestinal infections. The authors report three cases of B cereus bacteremia among injection drug users presenting within one month to an urban tertiary care hospital. Treatment with intravenous vancomycin was successful in all three cases. While temporal association suggested an outbreak, molecular studies of patient isolates using pulsed-field gel electrophoresis did not suggest a common source. A...
Fatma Deniz Aygun; Fatih Aygun; Halit Cam
Bacillus cereus can cause serious, life-threatening, systemic infections in immunocompromised patients. The ability of microorganism to form biofilm on biomedical devices can be responsible for catheter-related bloodstream infections. Other manifestations of severe disease are meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections. The most common feature in true bacteremia caused by Bacillus is the presence of an intravascular catheter. Herein, we report a case ...
Patel, Krunal; Gittens-Williams, Lisa; Apuzzio, Joseph J.; Martimucci, Kristina; Williams, Shauna F.
Background. Salmonella enterica serotype Typhi (S. Typhi) is an anaerobic gram-negative enteric rod that causes infection when contaminated food or water is ingested and may cause illness in pregnancy. Case. This is a patient who presented at 31 weeks' gestation with abdominal pain and fever and was diagnosed with S. Typhi bacteremia. Conclusion. S. Typhi should be considered in febrile patients with recent travel presenting with abdominal discomfort with or without elevated liver enzymes. PMID:28203469
Zhang, Yu; Chen, Xiao-Li; Huang, Ai-Wei; Liu, Su-Ling; Liu, Wei-Jiang; Zhang, Ni; Lu, Xu-Zai
Whether carbapenem resistance is associated with mortality in patients with Pseudomonas aeruginosa bacteremia is controversial. To address this issue, we conducted a systematic review and meta-analysis based on cohort studies. We searched PubMed and Embase databases to identify articles (up to April 2015). The DerSimonian and Laird random-effect model was used to generate a summary estimate of effect. Associations were evaluated in subgroups based on different patient characteristics and study quality criteria. Seven studies with a total of 1613 patients were finally included, of which 1 study had a prospective design, and the other 6 were retrospective. Our meta-analysis showed patients with carbapenem-resistant P. aeruginosa bacteremia were at a higher risk of death compared with those with carbapenem-susceptible P. aeruginosa bloodstream infections (pooled odds ratio (OR) from three studies reporting adjusted ORs: 3.07, 95% confidence interval (CI), 1.60–5.89; pooled OR from 4 studies only reporting crude ORs: 1.46, 95% CI, 1.10–1.94). The results were robust across a number of stratified analyses and a sensitivity analysis. We also calculated that 8%–18.4% of deaths were attributable to carbapenem resistance in four studies assessing the outcome with 30-day mortality, and these were 3% and 14.6%, respectively, in two studies using 7-day mortality or mortality during bacteremia as an outcome of interest. Carbapenem resistance had a deleterious impact on the mortality of P. aeruginosa bacteremia; however, the results should be interpreted cautiously because only three studies reporting adjusted ORs were included. More large-scale, well-designed prospective cohorts, as well as mechanistic studies, are urgently needed in the future. PMID:27004762
INTRODUCTION: Enterobacter can be included in the group of extended spectrum β-lactamases (EBSL)-producing bacteria, though few studies exist evaluating risk factors associated with this microorganism. A retrospective cohort study was conducted to determine risk factors associated with ESBL-producing-Enterobacter and mortality METHODS: A retrospective cohort study with 58 bacteremia caused by ESBL-producing-Enterobacter (28 cases) and non-ESBL (30 cases) RESULTS: Risk factors associated ...
Hemodialysis (HD) patients are particularly predisposed to infections. It seems that the HD procedure per se as well as disturbances in both innate and adaptive immunity significantly contribute to this susceptibility. Infections are the major cause of morbidity and the second cause of death following cardiovascular events in HD patients. Episodes of bacteremia and pneumonia account for the majority of severe infections in this population. In addition to these bacterial infections another com...
McLean, Thomas W; Rouster-Stevens, Kelly; Woods, Charles R; Shetty, Avinash K
Roseomonas is a newly described genus of pink-pigmented, gram-negative bacteria. Human infections caused by Roseomonas species are very rare. We report two cases of central venous catheter-related bacteremia associated with Roseomonas species (one case with R. gilardii and one with R. fauriae), and review the clinical spectrum of previously reported cases in the literature. Clinicals should be aware that Roseomonas species may cause serious infections in children.
Kim, Kyong-Young; Hur, Jaehyung; Jo, Wonyong; Hong, Jeongmin; Cho, Oh-Hyun; Kang, Dong Ho; Kim, Sunjoo; Bae, In-Gyu
Roseomonas are a gram-negative bacteria species that have been isolated from environmental sources. Human Roseomonas infections typically occur in immunocompromised patients, most commonly as catheter-related bloodstream infections. However, Roseomonas infections are rarely reported in immunocompetent hosts. We report what we believe to be the first case in Korea of infectious spondylitis with bacteremia due to Roseomonas mucosa in an immunocompetent patient who had undergone vertebroplasty for compression fractures of his thoracic and lumbar spine.
Kim, Kyong-Young; Hur, Jaehyung; Jo, Wonyong; Hong, Jeongmin; Cho, Oh-Hyun; Kang, Dong Ho; Kim, Sunjoo; Bae, In-Gyu
Roseomonas are a gram-negative bacteria species that have been isolated from environmental sources. Human Roseomonas infections typically occur in immunocompromised patients, most commonly as catheter-related bloodstream infections. However, Roseomonas infections are rarely reported in immunocompetent hosts. We report what we believe to be the first case in Korea of infectious spondylitis with bacteremia due to Roseomonas mucosa in an immunocompetent patient who had undergone vertebroplasty f...
Candice Baldeo; Carmen Isache; Cherisse Baldeo; Abubakr Bajwa
Bacteremia is currently one of the infections with the highest mortality in hospitals . Acinetobacter lwoffii and Acinetobacter baumannii are gram-negative bacteria and both represent opportunistic pathogens. In certain cases, the management can be challenging since these organisms can be highly resistant to antimicrobial agents. Clinical illnesses associated with Acinetobacter include pneumonia, meningitis, peritonitis, endocarditis and infections of the urinary tract and skin . Acinet...
Chávez, A C; Barrera, S; Leon, A; Trueba, G
Campylobacter fetus is an opportunistic pathogen which causes bacteremia and other invasive infections in immunocompromised patients who have been exposed to livestock or ingested animal products (uncooked meat or unpasteurized milk). The present report describes a C. fetus infection in a healthy adult (immunocompetent) who returned from a visit to the Ecuadorian Amazonia and who did not report exposure to the typical sources of infection.
Full Text Available Abstract Alcaligenes xylosoxidans is an aerobic, motile, oxidase and catalase positive, nonfermentative Gram negative bacillus. This bacterium has been isolated from intestine of humans and from various hospital or environmental water sources. A.xylosoxidans is both waterborne and results from the poor-hygienic conditions healthcare workers are in. In this case report, the bacteremia which appeared in a patient with pancreas cancer after ERCP was described.
Jiang, Lanxiang; Li, Hongen; Wang, Laiying; Song, Zexin; Shi, Lei; Li, Wenhua; Deng, Xuming; Wang, Jianfeng
Staphylococcus aureus, like other gram-positive pathogens, has evolved a large repertoire of virulence factors as a powerful weapon to subvert the host immune system, among which alpha-hemolysin (Hla), a secreted pore-forming cytotoxin, plays a preeminent role. We observed a concentration-dependent reduction in Hla production by S. aureus in the presence of sub-inhibitory concentrations of isorhamnetin, a flavonoid from the fruits of Hippophae rhamnoides L., which has little antibacterial activity. We further evaluate the effect of isorhamnetin on the transcription of the Hla-encoding gene hla and RNAIII, an effector molecule in the agr system. Isorhamnetin significantly down-regulated RNAIII expression and subsequently inhibited hla transcription. In a co-culture of S. aureus and lung cells, topical isorhamnetin treatment protected against S. aureus-induced cell injury. Isorhamnetin may represent a leading compound for the development of anti-virulence drugs against S. aureus infections.
van Eck van der Sluijs, A; Oosterheert, J J; Ekkelenkamp, M B; Hoepelman, I M; Peters, Edgar J G
Although Gram-negative micro-organisms are frequently associated with catheter-related bloodstream infections, the prognostic value and clinical implication of a positive catheter tip culture with Gram-negative micro-organisms without preceding bacteremia remains unclear. We determined the outcomes of patients with intravascular catheters colonized with these micro-organisms, without preceding positive blood cultures, and identified risk factors for the development of subsequent Gram-negative bacteremia. All patients with positive intravascular catheter tip cultures with Gram-negative micro-organisms at the University Medical Center, Utrecht, The Netherlands, between 2005 and 2009, were retrospectively studied. Patients with Gram-negative bacteremia within 48 h before catheter removal were excluded. The main outcome measure was bacteremia with Gram-negative micro-organisms. Other endpoints were length of the hospital stay, in-hospital mortality, secondary complications of Gram-negative bacteremia, and duration of intensive care admission. A total of 280 catheters from 248 patients were colonized with Gram-negative micro-organisms. Sixty-seven cases were excluded because of preceding positive blood cultures, leaving 213 catheter tips from 181 patients for analysis. In 40 (19%) cases, subsequent Gram-negative bacteremia developed. In multivariate analysis, arterial catheters were independently associated with subsequent Gram-negative bacteremia (odds ratio [OR] = 5.00, 95% confidence interval [CI]: 1.20-20.92), as was selective decontamination of the digestive tract (SDD) (OR = 2.47, 95% CI: 1.07-5.69). Gram-negative bacteremia in patients who received SDD was predominantly caused by cefotaxime (part of the SDD)-resistant organisms. Mortality was significantly higher in the group with subsequent Gram-negative bacteremia (35% versus 20%, OR = 2.12, 95% CI: 1.00-4.49). Patients with a catheter tip colonized with Gram-negative micro-organisms had a high chance of
Hansford, Jordan R; Phillips, Marianne; Cole, Catherine; Francis, Joshua; Blyth, Christopher C; Gottardo, Nicholas G
Bacillus cereus can cause serious infections in immunosuppressed patients. This population may be susceptible to B. cereus pneumonia, bacteremia, cellulitis, and rarely cerebral abscess. Here we report an 8-year-old boy undergoing induction therapy for acute lymphoblastic leukemia who developed multifocal B. cereus cerebral abscesses, highlighting the propensity for B. cereus to develop cerebral abscesses. A review of the literature over the past 25 years identified another 11 cases (3 children and 8 adults) of B. cereus cerebral abscess in patients undergoing cancer therapy. B. cereus cerebral abscesses were associated with a high mortality rate (42%) and significant morbidity. Notably, B. cereus bacteremia with concomitant cerebral abscess was associated with induction chemotherapy for acute leukemia in both children and adults (10 of 12 case reports). Our case report and review of the literature highlights the propensity for B. cereus to develop cerebral abscess(es). Therefore, early consideration for neuroimaging should be given for any neutropenic cancer patient identified with B. cereus bacteremia, in particular those with acute leukemia during induction therapy.
Kurihara, Yoko; Hitomi, Shigemi; Oishi, Tsuyoshi; Kondo, Tsukasa; Ebihara, Tsugio; Funayama, Yasunori; Kawakami, Yasushi
Although Proteus mirabilis is a common human pathogen, bacteremia caused by the organism, especially strains producing extended-spectrum beta-lactamase (ESBL), has rarely been investigated. We examined 64 cases of P. mirabilis bacteremia identified in the Minami Ibaraki Area, Japan, between 2001 and 2010 and compared the characteristics of cases with ESBL-producing and ESBL-non-producing strains (13 and 51 cases, respectively). All ESBL-producing strains with the gene encoding the CTX-M-2-group were genetically nonidentical. Isolation of ESBL-producing strains was significantly associated with onset in a hospital (p = 0.030), receiving hemodialysis (p = 0.0050), and previous antibiotic use within 1 month (p = 0.036; especially penicillin and/or cephalosporin (p = 0.010) and fluoroquinolone (p = 0.0069)). Isolation was also associated with inappropriate antibiotic therapy on the 1st and 4th days (p = 0.011 and 0.032, respectively) but not with mortality on the 30th day. These findings indicate that, for P. mirabilis bacteremia, isolation of ESBL-producing strains causes delay of initiating appropriate antimicrobial therapy but may not be associated with mortality.
Full Text Available Clostridium perfringens bacteremia is associated with adverse outcomes. Known risk factors include chronic kidney disease, malignancy, diabetes mellitus, and gastrointestinal disease. We present a 74-year-old man admitted with confusion, vomiting, and abdominal pain. Exam revealed tachycardia, hypotension, lethargy, distended abdomen, and cold extremities. He required intubation and aggressive resuscitation for septic shock. Laboratory data showed leukocytosis, metabolic acidosis, acute kidney injury, and elevated lipase. CT scan of abdomen revealed acute pancreatitis and small bowel ileus. He was started on vancomycin and piperacillin-tazobactam. Initial blood cultures were positive for C. perfringens on day five. Metronidazole and clindamycin were added to the regimen. Repeat CT (day 7 revealed pancreatic necrosis. The patient developed profound circulatory shock requiring multiple vasopressors, renal failure requiring dialysis, and bacteremia with vancomycin-resistant enterococci. Hemodynamic instability precluded surgical intervention and he succumbed to multiorgan failure. Interestingly, our isolate was beta lactamase producing. We review the epidemiology, risk factors, presentation, and management of C. perfringens bacteremia. This case indicates a need for high clinical suspicion for clostridial sepsis and that extended spectrum beta lactam antibiotic coverage may be inadequate and should be supplemented with use of clindamycin or metronidazole if culture is positive, until sensitivities are known.
Full Text Available Incidences of leukopenia caused by bacteremia have increased significantly and it is associated with prolonged hospital stay and increased cost. Immunoproteomic is a promising method to identify pathogenicity factors of different diseases. In the present study, we used immunoproteomic to analysis the pathogenicity factors in leukopenia caused by Klebsiella Pneumonia bacteremia. Approximately 40 protein spots localized in the 4 to 7 pI range were detected on two-dimensional electrophoresis gels, and 6 differentially expressed protein spots between 10 and 170 kDa were identified. Pathogenicity factors including S-adenosylmethionine synthetase, pyruvate dehydrogenase, glutathione synthetase, UDP-galactose-4-epimerase, acetate kinase A and elongation factor tu (EF-Tu. In validation of the pathogenicity factor, we used western blotting to show that Klebsiella pneumonia had higher (EF-Tu expression when they accompanied by leukopenia rather than leukocytosis. Thus, we report 6 pathogenicity factors of leukopenia caused by Klebsiella pneumonia bacteremia, including 5 housekeeping enzymes and EF-Tu. We suggest EF-Tu could be a potential pathogenicity factor for leukopenia caused by Klebsiella pneumonia.
Hepatic TNF-α production following gram-negative bacteremia or hypovolemic shock predisposes to acute lung injury. However, TNF-α expression may be modified by the manner in which the hepatic O2 supply is reduced and equally important, its timing relative to bacteremia. Brief secondary hypoxic stress of buffer-perfused rat livers downregulates E. Coli (EC)-induced TNF-α expression whereas low-flow ischemia preceding EC increases subsequent TNF-α production owing to reactive O2 species (ROS). Here we determined whether 30 min of constant-flow hypoxia preceding 109 intraportal EC likewise increases antigenic and bioactive TNF-α protein concentrations during reoxygenation via production of ROS. Multiple groups (n＝38) were studied over 180 minutes, circulation antigenic TNF-α decreased in H/R+EC vs. EC controls (1 939±640 vs. 12 407±2 476 μg/L at t＝180 min; P＜0.01, along with TNF-α bioactivity). TNF-α protein were not restored to control levels in ALLO+H/R+EC. Thus, EC-induced hepatic TNF-α production and export is strongly O2-dependent in intact liver regardless of the generation of ROS or the sequence of bacteremia and modest hypoxic stress.
Full Text Available Background. It is unclear if clinicians evaluate for concurrent bacteremia or UTI in young patients diagnosed with acute otitis media (AOM. Objectives. To describe how often, and under which circumstances, emergency providers investigate for bacteremia or UTI in 2–36 month olds with AOM. Methods. Cases of AOM were analyzed from the 2001–2004 National Hospital Ambulatory Medical Care Survey (NHAMCS-Emergency Department dataset. Results. AOM was diagnosed in 17% of the 10,847 recorded visits of 2–36 month olds. Of these visits, laboratory testing included: CBC: 7%, Blood culture: 4%, urinalysis or urine culture: 5%, and any of these tests: 9%. Rates of testing for 2–6 month olds with temperature ≥ 38.0 (CBC: 13%, blood culture: 9%, urinalysis or urine culture: 7%, any of the tests: 14% were not significantly different from testing of patients aged 6–12 months, or 12–36 months (all P>.1. Patients with temperature of ≥39.0 were more likely to have all tests, with the exception of urine investigation, than patients with temperature between 38.0 and 38.9. Conclusions. 17% of 2–36 month old patients seen in the emergency department are diagnosed with AOM. Investigating for bacteremia or UTI in these patients is not routine, even in febrile infants.
Yang, Hang; Zhang, Huaidong; Wang, Jing; Yu, Junping; Wei, Hongping
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most threatening pathogens due to its multi-drug resistance (MDR) and strong biofilm-forming capacity. Here, we described the screening of a novel chimeolysin (ClyF) that was active against planktonic and biofilm MRSA. Biochemical tests showed that ClyF was active against all S. aureus clinical isolates tested under planktonic and biofilm conditions. Structure analysis revealed that ClyF has an enhanced thermostability and pH tolerance than its parental lysin Pc by forming a hydrophobic cleft in the catalytic domain and an Ig-like structure in the cell-wall binding domain. A single intraperitoneally or topically administration of ClyF showed good MRSA removing efficacy in mouse models of bacteremia and burn wound infection, respectively. Our data collectively demonstrated that ClyF has good bactericidal activity against planktonic and biofilm MRSA both in vitro and in vivo, and therefore represents a useful antibacterial to combat MDR S. aureus. PMID:28067286
L.G.M. Bode (Lonneke)
markdownabstract__Abstract__ S. aureus colonizes the skin and mucosae of a proportion of the human population. Carriers of S. aureus are at increased risk of developing infections with this pathogen. The aim of this thesis was to add to the prevention of healthcare associated S. aureus infections.
Alexopoulou, Alexandra; Vasilieva, Larisa; Agiasotelli, Danai; Siranidi, Kyriaki; Pouriki, Sophia; Tsiriga, Athanasia; Toutouza, Marina; Dourakis, Spyridon P
AIM: To evaluate the epidemiology and outcomes of culture-positive spontaneous bacterial peritonitis (SBP) and spontaneous bacteremia (SB) in decompensated cirrhosis. METHODS: We prospectively collected clinical, laboratory characteristics, type of administered antibiotic, susceptibility and resistance of bacteria to antibiotics in one hundred thirty cases (68.5% males) with positive ascitic fluid and/or blood cultures during the period from January 1, 2012 to May 30, 2014. All patients with SBP had polymorphonuclear cell count in ascitic fluid > 250/mm3. In patients with SB a thorough study did not reveal any other cause of bacteremia. The patients were followed-up for a 30-d period following diagnosis of the infection. The final outcome of the patients was recorded in the end of follow-up and comparison among 3 groups of patients according to the pattern of drug resistance was performed. RESULTS: Gram-positive-cocci (GPC) were found in half of the cases. The most prevalent organisms in a descending order were Escherichia coli (33), Enterococcus spp (30), Streptococcus spp (25), Klebsiella pneumonia (16), S. aureus (8), Pseudomanas aeruginosa (5), other Gram-negative-bacteria (GNB) (11) and anaerobes (2). Overall, 20.8% of isolates were multidrug-resistant (MDR) and 10% extensively drug-resistant (XDR). Health-care-associated (HCA) and/or nosocomial infections were present in 100% of MDR/XDR and in 65.5% of non-DR cases. Meropenem was the empirically prescribed antibiotic in HCA/nosocomial infections showing a drug-resistance rate of 30.7% while third generation cephalosporins of 43.8%. Meropenem was ineffective on both XDR bacteria and Enterococcus faecium (E. faecium). All but one XDR were susceptible to colistin while all GPC (including E. faecium) and the 86% of GNB to tigecycline. Overall 30-d mortality was 37.7% (69.2% for XDR and 34.2% for the rest of the patients) (log rank, P = 0.015). In multivariate analysis, factors adversely affecting outcome included
Full Text Available BACKGROUND: The epidemiology of non-Typhi Salmonella (NTS bacteremia in Africa will likely evolve as potential co-factors, such as HIV, malaria, and urbanization, also change. METHODS: As part of population-based surveillance among 55,000 persons in malaria-endemic, rural and malaria-nonendemic, urban Kenya from 2006-2009, blood cultures were obtained from patients presenting to referral clinics with fever ≥38.0°C or severe acute respiratory infection. Incidence rates were adjusted based on persons with compatible illnesses, but whose blood was not cultured. RESULTS: NTS accounted for 60/155 (39% of blood culture isolates in the rural and 7/230 (3% in the urban sites. The adjusted incidence in the rural site was 568/100,000 person-years, and the urban site was 51/100,000 person-years. In both sites, the incidence was highest in children 85% of blood NTS isolates in both sites, but only 21% (urban and 64% (rural of stool NTS isolates. Overall, 76% of S. Typhimurium blood isolates were multi-drug resistant, most of which had an identical profile in Pulse Field Gel Electrophoresis. In the rural site, the incidence of NTS bacteremia increased during the study period, concomitant with rising malaria prevalence (monthly correlation of malaria positive blood smears and NTS bacteremia cases, Spearman's correlation, p = 0.018 for children, p = 0.16 adults. In the rural site, 80% of adults with NTS bacteremia were HIV-infected. Six of 7 deaths within 90 days of NTS bacteremia had HIV/AIDS as the primary cause of death assigned on verbal autopsy. CONCLUSIONS: NTS caused the majority of bacteremias in rural Kenya, but typhoid predominated in urban Kenya, which most likely reflects differences in malaria endemicity. Control measures for malaria, as well as HIV, will likely decrease the burden of NTS bacteremia in Africa.
Araoka, Hideki; Baba, Masaru; Kimura, Muneyoshi; Abe, Masahiro; Inagawa, Hiroko; Yoneyama, Akiko
The aim of this study was to clarify the clinical characteristics of patients with Helicobacter cinaedi bacteremia and the time required for blood cultures to become positive. The medical records of all patients with H. cinaedi bacteremia at Toranomon Hospital and Toranomon Hospital Kajigaya between March 2009 and March 2013 were retrospectively reviewed. Sixty-three patients, 34 men and 29 women with a median age of 67 years (range, 37 to 88 years), were diagnosed with H. cinaedi bacteremia. A total of 51,272 sets of blood cultures were obtained during the study period, of which 5,769 sets of blood cultures were positive for some organism and 126 sets were H. cinaedi positive. The time required for blood cultures to become positive for H. cinaedi was ≤5 days in 69 sets (55%) and >5 days in 57 sets (45%). Most patients had an underlying disease, including chronic kidney disease (21 cases), solid tumor (19 cases), hematological malignancy (13 cases), diabetes mellitus (8 cases), chronic liver disease (6 cases), and postorthopedic surgery (3 cases). Only 1 patient had no apparent underlying disease. The clinical symptoms included cellulitis in 24 cases, colitis in 7 cases, and fever only in 27 cases, including 7 cases of febrile neutropenia. The 30-day mortality rate of H. cinaedi bacteremia was 6.3%. In conclusion, most cases of H. cinaedi bacteremia occurred in immunocompromised patients. We might have overlooked nearly half of the H. cinaedi bacteremia cases if the duration of monitored blood culture samples had been within 5 days. Therefore, when clinicians suspect H. cinaedi bacteremia, the observation period for blood cultures should be extended.
Full Text Available Abstract Background Epidemic outbreaks of multi-drug resistant (MDR Acinetobacter baumannii (AB in intensive care units (ICUs are increasing. The incidence of MDR AB bacteremia, which develops as a result of colonization, is increasing through widespread dissemination of the pathogen, and further colonization. We sought to determine risk factors for MDR AB bacteremia in patients colonized with MDR AB in the ICU. Methods We conducted a retrospective, observational study of 200 patients colonized with MDR AB in the ICU at Severance Hospital, South Korea during the outbreak period between January 2008 and December 2009. Results Of the 200 patients colonized with MDR AB, 108 developed MDR AB bacteremia, and 92 did not. APACHE II scores were higher in bacteremic than non-bacteremic patients at the time of ICU admission and colonization (24.0 vs. 21.6; P = 0.035, 22.9 vs. 16.8; P P = 0.923, but the duration of time at risk was shorter in bacteremic patients (12.1 vs. 6.0 days; P = 0.016. A recent invasive procedure was a significant risk factor for development of bacteremia (odds ratio = 3.85; 95% CI 1.45-10.24; P = 0.007. Multivariate analysis indicated infection and respiratory failure at the time of ICU admission, maintenance of mechanical ventilation, maintenance of endotracheal tube instead of switching to a tracheostomy, recent central venous catheter insertion, bacteremia caused by other microorganism after colonization by MDR AB, and prior antimicrobial therapy, were significant risk factors for MDR AB bacteremia. Conclusions Patients in the ICU, colonized with MDR AB, should be considered for minimizing invasive procedures and early removal of the invasive devices to prevent development of MDR AB bacteremia.
Fernandes, I.; S. Carvalho; Machado, S.; Alves,R.; Selores, M.
ABSTRACT The authors describe a clinical case of a six-year-old boy with history of a segmental brownish maculopapular skin eruption on his left thoracic and lumbar wall, since the last four months. Based on clinical and histological findings he was diagnosed with segmental lichen aureus.
Altman, D. R.; Sebra, R.; Hand, J.; Attie, O.; Deikus, G.; Carpini, K. W. D.; Patel, G.; Rana, M.; Arvelakis, A.; Grewal, P.; Dutta, J.; Rose, H.; Shopsin, B.; Daefler, S.; Schadt, E.; Kasarskis, A.; van Bakel, H.; Bashir, A.; Huprikar, S.
Donor-derived bacterial infection is a recognized complication of solid organ transplantation (SOT). The present report describes the clinical details and successful outcome in a liver transplant recipient despite transmission of methicillin-resistant Staphylococcus aureus (MRSA) from a deceased donor with MRSA endocarditis and bacteremia. We further describe whole genome sequencing (WGS) and complete de novo assembly of the donor and recipient MRSA isolate genomes, which confirms that both isolates are genetically 100% identical. We propose that similar application of WGS techniques to future investigations of donor bacterial transmission would strengthen the definition of proven bacterial transmission in SOT, particularly in the presence of highly clonal bacteria such as MRSA. WGS will further improve our understanding of the epidemiology of bacterial transmission in SOT and the risk of adverse patient outcomes when it occurs. PMID:25250641
Wi, Yu Mi; Park, Young Kyoung; Moon, Chisook; Ryu, Seong Yeol; Lee, Hyuck; Ki, Hyun Kyun; Cheong, Hae Suk; Son, Jun Seong; Lee, Jin Seo; Kwon, Ki Tae; Kim, June Myong; Ha, Young Eun; Kang, Cheol In; Ko, Kwan Soo; Chung, Doo Ryeon; Peck, Kyong Ran; Song, Jae-Hoon
We evaluated the clinical significance of the cefazolin inoculum effect (CIE) in methicillin-susceptible Staphylococcus aureus (MSSA) isolates. In total, 146 isolates were recovered from patients with MSSA bacteremia at 9 hospitals in Korea. The CIE was observed in 16 MSSA isolates, and while type A was the only detected β-lactamase in MSSA isolates exhibiting the CIE, no strains expressing type B, C, or D β-lactamases exhibited this effect. The CIE was only observed in agr group III and I isolates and was significantly more common in isolates with agr dysfunction than in those with functional agr (P<0.001). Even among isolates producing type A β-lactamase, the CIE was also prevalent in isolates with dysfunctional agr than in isolates with functional agr (P=0.025). This study demonstrates an association between the CIE of MSSA isolates and agr dysfunction, in addition to those between the CIE and type A β-lactamase.
Vrieling, Manouk; Boerhout, Eveline M.; Wigcheren, Van Glenn F.; Koymans, Kirsten J.; Mols-Vorstermans, Tanja G.; Haas, de Carla J.C.; Aerts, Piet C.; Daemen, Ineke J.J.M.; Kessel, Van Kok P.M.; Koets, Ad P.; Rutten, Victor P.M.G.; Nuijten, Piet J.M.; Strijp, van Jos A.G.; Benedictus, Lindert
Staphylococcus aureus is a major human and animal pathogen and a common cause of mastitis in cattle. S. aureus secretes several leukocidins that target bovine neutrophils, crucial effector cells in the defence against bacterial pathogens. In this study, we investigated the role of staphylococcal leu
Gottschalk, Sanne; Ingmer, Hanne; Thomsen, Line E.
, we found that LP5 was protease resistant. However, the dltA and vraF genes, involved in reducing the net anionic charge of the bacterial cell envelope and sensing of antimicrobial peptides, respectively, played a role in the tolerance of S. aureus against LP5. In addition, the exposure of S. aureus...
Third generation cephalosporin resistant Enterobacteriaceae and multidrug resistant gram-negative bacteria causing bacteremia in febrile neutropenia adult cancer patients in Lebanon, broad spectrum antibiotics use as a major risk factor, and correlation with poor prognosis
Full Text Available Bacteremia remains a major cause of life-threatening complications in patients receiving anticancer chemotherapy. The spectrum and susceptibility profiles of causative microorganisms differ with time and place. Data from Lebanon are scarce. We aim at evaluating the epidemiology of bacteremia in cancer patients in a university hospital in Lebanon, emphasizing antibiotic resistance and risk factors of multi-drug resistant organism (MDRO-associated bacteremia.This is a retrospective study of 75 episodes of bacteremia occurring in febrile neutropenic patients admitted to the hematology-oncology unit at Makassed General Hospital, Lebanon, from October 2009-January 2012.It corresponds to epidemiological data on bacteremia episodes in febrile neutropenic cancer patients including antimicrobial resistance and identification of risk factors associated with third generation cephalosporin resistance (3GCR and MDRO-associated bacteremia. Out of 75 bacteremias, 42.7% were gram-positive (GP, and 57.3% were gram-negative (GN. GP bacteremias were mostly due to methicillin-resistant coagulase negative staphylococci (28% of total bacteremias and 66% of GP bacteremias. Among the GN bacteremias, Escherichia coli (22.7% of total, 39.5% of GN organisms and Klebsiellapneumoniae(13.3% of total, 23.3% of GN organisms were the most important causative agents. GN bacteremia due to 3GC sensitive (3GCS bacteria represented 28% of total bacteremias, while 29% were due to 3GCR bacteria and 9% were due to carbapenem-resistant organisms. There was a significant correlation between bacteremia with MDRO and subsequent intubation, sepsis and mortality. Among potential risk factors, only broad spectrum antibiotic intake >4 days before bacteremia was found to be statistically significant for acquisition of 3GCR bacteria. Using carbapenems or piperacillin/ tazobactam>4 days before bacteremia was significantly associated with the emergence of MDRO (p value<0.05.
Álvarez, R; Viñas-Castillo, L; Lepe-Jiménez, J A; García-Cabrera, E; Cisneros-Herreros, J M
The time to positivity (TTP) of blood cultures has been associated with increased mortality in bacteremia caused by several microorganisms. The aim of this study is to evaluate the relationship between TTP and prognosis, clinical presentation and extended spectrum B-lactamase (ESBL)-production in patients with Escherichia coli bacteremia. This is a retrospective observational study involving 226 adult patients with E. coli bacteremia. Data collected included underlying diseases, clinical presentation, prognosis factors, TTP, ESBL-production and outcome. Thirty-one (14%) patients had severe sepsis and 29 (13%) septic shock at presentation. Thirty-three (14%) strains were ESBL-producers. Thirty-nine (17%) patients died during admission and 17 (7.5%) within 48 hours. The median TTP was 8.3 hours (range, 0.42–76.5). It was significantly shorter in patients with septic shock (6.23 h, range 1.12–47.29 h vs. 8.51 h, range 0.42–76.50 h; p = 0.018). Rapid growth of E. coli, Pitt index >1.5, non-urinary source and Charlson score >2 were selected as independent risk factors of in-hospital mortality by the multivariate analysis. ESBL-production was not associated with modifications in TTP. Lower TTP is an independent risk factor for septic shock and poor outcome in episodes of E. coli bacteremia. The TTP in E. coli bacteremia is not significantly modified by ESBL-production.
Gil-Sande, E.; Brun-Otero, M.; Campo-Cerecedo, F.; Esteban, E.; Aguilar, L.; García-de-Lomas, J.
Gordonia terrae has been reported to be a rare cause of bacteremia. We report the first case of bacteremia associated with acute cholecystitis. Commercial biochemical testing was not able to identify the strain at the genus level, classifying it instead as Rhodococcus sp. Definitive identification was obtained by sequencing of the 16S rRNA gene. PMID:16825404
Day, Michael W; Jackson, Lydgia A; Akins, Darrin R; Dyer, David W; Chavez-Bueno, Susana
Neonatal bacteremia Escherichia coli strains commonly belong to the K1 capsular type. Their ability to cause invasive neonatal disease appears to be determined by other virulence factors that have yet to be identified. We report here the genome sequences of four E. coli neonatal bacteremia isolates, including that of the archetypal strain RS218.
David B Friedman
Full Text Available Staphylococcus aureus pathogenesis is significantly influenced by the iron status of the host. However, the regulatory impact of host iron sources on S. aureus gene expression remains unknown. In this study, we combine multivariable difference gel electrophoresis and mass spectrometry with multivariate statistical analyses to systematically cluster cellular protein response across distinct iron-exposure conditions. Quadruplicate samples were simultaneously analyzed for alterations in protein abundance and/or post-translational modification state in response to environmental (iron chelation, hemin treatment or genetic (Deltafur alterations in bacterial iron exposure. We identified 120 proteins representing several coordinated biochemical pathways that are affected by changes in iron-exposure status. Highlighted in these experiments is the identification of the heme-regulated transport system (HrtAB, a novel transport system which plays a critical role in staphylococcal heme metabolism. Further, we show that regulated overproduction of acidic end-products brought on by iron starvation decreases local pH resulting in the release of iron from the host iron-sequestering protein transferrin. These findings reveal novel strategies used by S. aureus to acquire scarce nutrients in the hostile host environment and begin to define the iron and heme-dependent regulons of S. aureus.
Abhrajit Ganguly; Saibal Das; Jayanta Kumar Dey; Somnath Mondal
With increasing incidence of Clostridium difficile (C. difficile) associated diarrhea and pseudomembranous colitis, several extra-intestinal manifestations of the organism have been unmasked which include-bacteremia, brain abscess, pericarditis etc. We report a rare and interesting case of C. difficile bacteremia and subsequent meningitis in a 10 year old child. The child was immune competent, which further raises the question about the virulent possibilities of the organism and its implications in the near future. The condition resulted from a prolonged treatment with intravenous (I.V.) cefotaxime for staphylococcal pyogenic arthritis. The child recovered from the septic arthritis but on the 7th day post-admission developed features of bacteremia. The child was later treated with intravenous metronidazole and vancomycin and he was discharged on the 21st day post-admission. No recurrence of symptoms was noted.
Full Text Available With increasing incidence of Clostridium difficile (C. difficile associated diarrhea and pseudomembranous colitis, several extra-intestinal manifestations of the organism have been unmasked which include-bacteremia, brain abscess, pericarditis etc. We report a rare and interesting case of C. difficile bacteremia and subsequent meningitis in a 10 year old child. The child was immune competent, which further raises the question about the virulent possibilities of the organism and its implications in the near future. The condition resulted from a prolonged treatment with intravenous (I.V. cefotaxime for staphylococcal pyogenic arthritis. The child recovered from the septic arthritis but on the 7th day post-admission developed features of bacteremia. The child was later treated with intravenous metronidazole and vancomycin and he was discharged on the 21st day post-admission. No recurrence of symptoms was noted.
Conclusions: DNA-based detection and characterization of bacteria in DFUs are rapid and efficient and can assist in accurate, targeted antibiotic therapy of DFU infections. The majority of S. aureus detected in this study were highly virulent and also resistant to methicillin. Further studies are required to understand the role of S. aureus in DFU trajectory. [Int J Basic Clin Pharmacol 2014; 3(6.000: 978-982
Morphological and molecular imaging of hematogenously inoculated and disseminated Staphylococcus aureus lesions in domestic juvenile female pigs by PET/CT. The bio-distribution of the radionuclides 18F-FDG, 11C-methionine, 11C-PK11195, and 68Ga-citrate in pigs is presented
Afzelius, Pia; Nielsen, Ole Lerberg; Alstrup, Aage Kristian Olsen
. Bacteremia may give rise to bacterial spread to different tissues such as e.g. heart, joints, spleen, bones, and skin/soft tissue. Staphylococcus aureus is a conditional pathogen: it is carried on many humans and animals without symptoms, but it is also able to cause serious diseases like osteomyelitis......, pneumonia, endocarditis, bacteremia, meningitis, and toxic shock syndrome. Conventional imaging procedures as X-ray, Computed Tomography (CT), Magnetic Resonance Imaging, and ultrasound are often first-line imaging methods for identification and localization of infection. These methods are, however......, not always successful in finding the site of infection. Early identification and localization of infection is critical for the appropriate and timely selection of therapy. The aim of this study was thus; a head to head comparison of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) to PET...
Full Text Available (1 To develop a clinical prediction rule to identify patients with bacteremia, using only information that is readily available in the emergency room (ER of community hospitals, and (2 to test the validity of that rule with a separate, independent set of data.Multicenter retrospective cohort study.To derive the clinical prediction rule we used data from 3 community hospitals in Japan (derivation. We tested the rule using data from one other community hospital (validation, which was not among the three "derivation" hospitals.Adults (age ≥ 16 years old who had undergone blood-culture testing while in the ER between April 2011 and March 2012. For the derivation data, n = 1515 (randomly sampled from 7026 patients, and for the validation data n = 467 (from 823 patients.We analyzed 28 candidate predictors of bacteremia, including demographic data, signs and symptoms, comorbid conditions, and basic laboratory data. Chi-square tests and multiple logistic regression were used to derive an integer risk score (the "ID-BactER" score. Sensitivity, specificity, likelihood ratios, and the area under the receiver operating characteristic curve (i.e., the AUC were computed.There were 241 cases of bacteremia in the derivation data. Eleven candidate predictors were used in the ID-BactER score: age, chills, vomiting, mental status, temperature, systolic blood pressure, abdominal sign, white blood-cell count, platelets, blood urea nitrogen, and C-reactive protein. The AUCs was 0.80 (derivation and 0.74 (validation. For ID-BactER scores ≥ 2, the sensitivities for derivation and validation data were 98% and 97%, and specificities were 20% and 14%, respectively.The ID-BactER score can be computed from information that is readily available in the ERs of community hospitals. Future studies should focus on developing a score with a higher specificity while maintaining the desired sensitivity.
Full Text Available Staphylococcus aureus is both a major bacterial pathogen as well as a common member of the human skin microbiota. Due to its widespread prevalence as an asymptomatic skin colonizer and its importance as a source of skin and soft tissue infections, an improved understanding of how S. aureus attaches to, grows within, and breaches the stratified layers of the epidermis is of critical importance. Three-dimensional organotypic human skin culture models are informative and tractable experimental systems for future investigations of the interactions between S. aureus and the multifaceted skin tissue. We propose that S. aureus virulence factors, primarily appreciated for their role in pathogenesis of invasive infections, play alternative roles in promoting asymptomatic bacterial growth within the skin. Experimental manipulations of these cultures will provide insight into the many poorly understood molecular interactions occurring at the interface between S. aureus and stratified human skin tissue.
Full Text Available Rats with Metabolic Syndrome (MetaS have a dysregulated immune response to the aseptic trauma of surgery. We hypothesized that rats with MetaS would have dysregulated inflammation, increased lung injury, and less effective antibacterial defenses during Staphylococcus (S. aureus sepsis as compared to rats without MetaS. Low capacity runner (LCR; a model of MetaS and high capacity runner (HCR rats were challenged intravenously with S. aureus bacteria. After 48 h, inflammatory mediators and bacteria were quantified in the blood, bronchoalveolar lavage fluid (BALF, and lung homogenates. Lungs were analyzed histologically. BALF protein and lung wet-dry ratios were quantified to assess for vascular leak. Endpoints were compared in infected LCR vs HCR rats. LCR rats had higher blood and lung S. aureus counts, as well as higher levels of IL-6 in plasma, lungs and BALF, MIP-2 in plasma and lung, and IL-17A in lungs. Conversely, LCR rats had lower levels of IL-10 in plasma and lungs. Although lactate levels, and liver and renal function tests were similar between groups, LCR rats had higher BALF protein and lung wet-dry ratios, and more pronounced acute lung injury histologically. During S. aureus bacteremia, as compared with HCR rats, LCR (MetaS rats have heightened pro-inflammatory responses, accompanied by increased acute lung injury and vascular leak. Notably, despite an augmented pro-inflammatory phenotype, LCR rats have higher bacterial levels in their blood and lungs. The MetaS state may exacerbate lung injury and vascular leak by attenuating the inflammation-resolving response, and by weakening antimicrobial defenses.
Feng, Xiaomei; Maze, Mervyn; Koch, Lauren G; Britton, Steven L; Hellman, Judith
Rats with Metabolic Syndrome (MetaS) have a dysregulated immune response to the aseptic trauma of surgery. We hypothesized that rats with MetaS would have dysregulated inflammation, increased lung injury, and less effective antibacterial defenses during Staphylococcus (S.) aureus sepsis as compared to rats without MetaS. Low capacity runner (LCR; a model of MetaS) and high capacity runner (HCR) rats were challenged intravenously with S. aureus bacteria. After 48 h, inflammatory mediators and bacteria were quantified in the blood, bronchoalveolar lavage fluid (BALF), and lung homogenates. Lungs were analyzed histologically. BALF protein and lung wet-dry ratios were quantified to assess for vascular leak. Endpoints were compared in infected LCR vs HCR rats. LCR rats had higher blood and lung S. aureus counts, as well as higher levels of IL-6 in plasma, lungs and BALF, MIP-2 in plasma and lung, and IL-17A in lungs. Conversely, LCR rats had lower levels of IL-10 in plasma and lungs. Although lactate levels, and liver and renal function tests were similar between groups, LCR rats had higher BALF protein and lung wet-dry ratios, and more pronounced acute lung injury histologically. During S. aureus bacteremia, as compared with HCR rats, LCR (MetaS) rats have heightened pro-inflammatory responses, accompanied by increased acute lung injury and vascular leak. Notably, despite an augmented pro-inflammatory phenotype, LCR rats have higher bacterial levels in their blood and lungs. The MetaS state may exacerbate lung injury and vascular leak by attenuating the inflammation-resolving response, and by weakening antimicrobial defenses.
Almuzara, Marisa; Bonofiglio, Laura; Cittadini, Roberto Arnaldo; Vera Ocampo, C.; Montilla, A.; Del Castillo, M.; Ramirez, Maria Soledad; Mollerach, Marta Eugenia; C. Vay
First Case of Streptococcus lutetiensis Bacteremia Involving a Clindamycin-Resistant Isolate Carrying the lnuB Gene Fil: Almuzara, Marisa. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina; Fil: Bonofiglio, Laura. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; Argentina; Fil: Cittadini, Roberto Arnaldo. Instituto Nacional de Tecnologia Agropecuaria;...
Goel, Noopur; Munshi, Lubna Bashir; Thyagarajan, Braghadheeswar
Patients with history of intravenous drug abuse are noted to be at risk of several infections including HIV, endocarditis, and other opportunistic infections. We report the case of a patient with sustained Bacillus cereus bacteremia despite use of multiple antibiotic regimens during his inpatient stay. Our case highlights the importance of high suspicion for active drug use inside the hospital in such patients. This is important in order to minimize unnecessary diagnostic workup and provide adequate treatment and safe hospital stay for these patients.
Full Text Available Patients with history of intravenous drug abuse are noted to be at risk of several infections including HIV, endocarditis, and other opportunistic infections. We report the case of a patient with sustained Bacillus cereus bacteremia despite use of multiple antibiotic regimens during his inpatient stay. Our case highlights the importance of high suspicion for active drug use inside the hospital in such patients. This is important in order to minimize unnecessary diagnostic workup and provide adequate treatment and safe hospital stay for these patients.
Michael A Benusic
Full Text Available Bacillus cereus is a ubiquitous spore-forming organism that is infrequently implicated in extraintestinal infections. The authors report three cases of B cereus bacteremia among injection drug users presenting within one month to an urban tertiary care hospital. Treatment with intravenous vancomycin was successful in all three cases. While temporal association suggested an outbreak, molecular studies of patient isolates using pulsed-field gel electrophoresis did not suggest a common source. A review of the association of B cereus infections with heroin use and treatment of this pathogen is provided.
Benusic, Michael A; Press, Natasha M; Hoang, Linda Mn; Romney, Marc G
Bacillus cereus is a ubiquitous spore-forming organism that is infrequently implicated in extraintestinal infections. The authors report three cases of B cereus bacteremia among injection drug users presenting within one month to an urban tertiary care hospital. Treatment with intravenous vancomycin was successful in all three cases. While temporal association suggested an outbreak, molecular studies of patient isolates using pulsed-field gel electrophoresis did not suggest a common source. A review of the association of B cereus infections with heroin use and treatment of this pathogen is provided.
Abdulaziz Ahmed Hashi
Full Text Available Staphylococcus pettenkoferi is a relatively recently described coagulase-negative staphylococci species first described in 2002. Since then, nine additional cases of infection caused by this species have been reported in various countries around the world, including Germany, Belgium, France, South Korea, Italy, Brazil and Mexico. The present report describes a case of S pettenkoferi peripheral line-associated bacteremia. To our knowledge, the present report is the first description of human infection caused by S pettenkoferi in Canada. The present report also provides an overview of the laboratory detection of uncommon coagulase-negative staphylococci.
博士(医学) 乙第2895号(主論文の要旨、要約、本文),著者名:Sayaka Tago・Yuji Hirai・Yusuke Ainoda・Takahiro Fujita・Ken Kikuchi,タイトル:Gram-negative rod bacteremia after cardiovascular surgery: Clinical features and prognostic factors,掲載誌:Journal of microbiology(1684-1182), immunology and infection,著作権関連情報:ℂ2015, Taiwan Society of Microbiology. Published by Elsevier Taiwan LLC. All rights reserved.DOI: 10.1016/j.jmii.2015.07.008
Laupland, Kevin B; Schønheyder, Henrik C; Østergaard, Christian;
OBJECTIVES: Haemophilus influenzae is an important cause of invasive infection but contemporary data in non-selected populations is limited. METHODS: Population-based surveillance for Haemophilus influenzae bacteremia was conducted in seven regions in Australia, Canada, and Denmark during 2000...... independently associated with death at 30-days in logistic regression analysis included male gender, hospital-onset disease, older age, and lower respiratory tract, central nervous system, or unknown focus of infection. CONCLUSIONS: Haemophilus influenzae is an important cause of morbidity and mortality...
Yamagami, Keiko; Miyashita, Tomoko; Nakamura, Tomoyuki; Shirano, Michinori; Nakamura, Tadahiro; Kameda, Kazuaki; Nishijima, Masayoshi; Imanishi, Masahiro; Yang, Xi; Kanegane, Hirokazu
A 24-year-old man presented with fever and pleural effusion predominantly containing lymphocytes. Cultures of the pleural effusion and blood revealed Campylobacter fetus, and laboratory studies showed a low serum level of immunoglobulin. The patient was diagnosed with C. fetus pleuritis, bacteremia and primary hypogammaglobulinemia, and subsequent treatment with meropenem and immunoglobulin improved his condition. Although the underlying cause of the primary hypogammaglobulinemia remains unclear, the patient's status improved under immunoglobulin replacement therapy. C. fetus pleuritis is a rare infectious disease usually observed in immunocompromised hosts. We herein describe the first report of C. fetus pleuritis in a young adult with primary hypogammaglobulinemia.
Antwan Atia; Tejas Raiyani; Pranav Patel; Robert Patton; Mark Young
A 67-years-old male presented with periumbilical abdominal pain,fever and jaundice.His anaerobic blood culture was positive for clostridium perfringens.Computed tomogram scan of the abdomen and abdominal ultrasound showed normal gallbladder and common bile duct (CBD).Subsequently magnetic resonance cholangiopancreaticogram showed choledocholithiasis.Endoscopic retrograde cholangiopancreaticogramwith sphincterotomy and CBD stone extraction was performed.The patient progressively improved with antibiotic therapy Choledocholithiasis should be considered as a source of clostridium perfringens bacteremia especially in the setting of elevated liver enzymes with cholestatic pattern.
Michon, Anne-Laure; Saumet, Laure; Bourdier, Alice; Haouy, Stéphanie; Sirvent, Nicolas; Marchandin, Hélène
Roseomonas are described as opportunistic pathogens rarely involved in human infections. Their identification requires molecular methods and their antimicrobial susceptibility pattern varies according to the species. We report the first case of bacteremia due to Roseomonas mucosa in a child with leukemia and reviewed pediatric cases of Roseomonas infection, for which undoubted strain identification was available. Favorable outcome was observed despite resistance to numerous β-lactams that may account for delayed effective treatment, suggesting the low virulence of Roseomonas in children. Here, the strain also displayed unusual resistance to imipenem, highlighting the possible acquisition of additional resistance by this pathogen.
Full Text Available We present a 63-year-old man treated with alemtuzumab for chronic lymphocytic leukemia who developed multiple angiomatous papules and fever. Real-time polymerase chain reaction (RT-PCR from a skin lesion and blood sample revealed Bartonella quintana as causative agent confirming the diagnosis of bacillary angiomatosis with bacteremia. Treatment with doxycycline, initially in combination with gentamicin, led to complete resolution of the lesions. This case shows the importance of considering bacillary angiomatosis as a rare differential diagnosis of angiomatous lesions in the immunocompromised patient, particularly in chronic lymphocytic leukemia and following lymphocyte depleting treatments as alemtuzumab.
Secor, Patrick R; Jennings, Laura K; James, Garth A; Kirker, Kelly R; Pulcini, Elinor Delancey; McInnerney, Kate; Gerlach, Robin; Livinghouse, Tom; Hilmer, Jonathan K; Bothner, Brian; Fleckman, Philip; Olerud, John E; Stewart, Philip S
Staphylococcus aureus biofilms are associated with chronic skin infections and are orders of magnitude more resistant to antimicrobials and host responses. S. aureus contains conserved nonribosomal peptide synthetases that produce the cyclic dipeptides tyrvalin and phevalin (aureusimine A and B, respectively). The biological function of these compounds has been speculated to be involved in virulence factor gene expression in S. aureus, protease inhibition in eukaryotic cells, and interspecies bacterial communication. However, the exact biological role of these compounds is unknown. Here, we report that S. aureus biofilms produce greater amounts of phevalin than their planktonic counterparts. Phevalin had no obvious impact on the extracellular metabolome of S. aureus as measured by high-performance liquid chromatography-mass spectrometry and nuclear magnetic resonance. When administered to human keratinocytes, phevalin had a modest effect on gene expression. However, conditioned medium from S. aureus spiked with phevalin amplified differences in keratinocyte gene expression compared to conditioned medium alone. Phevalin may be exploited as potential biomarker and/or therapeutic target for chronic, S. aureus biofilm-based infections.
Ouyang, Ping; Sun, Mao; He, Xuewen; Wang, Kaiyu; Yin, Zhongqiong; Fu, Hualin; Li, Yinglun; Geng, Yi; Shu, Gang; He, Changliang; Liang, Xiaoxia; Lai, Weiming; Li, Lixia; Zou, Yuanfeng; Song, Xu; Yin, Lizi
Staphylococcus aureus (S. aureus) is a common Gram-positive bacterium that causes serious infections in human and animals. With the continuous emergence of the methicillin-resistant S. aureus (MRSA) strains, antibiotics have limited efficacy in treating MRSA infections. Accordingly, novel agents that act on new targets are desperately needed to combat these infections. S. aureus alpha-hemolysin plays an indispensable role in its pathogenicity. In this study, we demonstrate that sclareol, a fragrant chemical compound found in clary sage, can prominently decrease alpha-hemolysin secretion in S. aureus strain USA300 at sub-inhibitory concentrations. Hemolysis assays, western-blotting and RT-PCR were used to detect the production of alpha-hemolysin in the culture supernatant. When USA300 was co-cultured with and A549 epithelial cells, sclareol could protect A549 cells at a final concentration of 8 µg/ml. The protective capability of sclareol against the USA300-mediated injury of A549 cells was further shown by cytotoxicity assays and live/dead analysis. In conclusion, sclareol was shown to inhibit the production of S. aureus alpha-hemolysin. Sclareol has potential for development as a new agent to treat S. aureus infections.
Uchiyama, Satoshi; Valderrama, J. Andrés; Ajayi, Clement; Sollid, Johanna U. E.; van Sorge, Nina M.; Nizet, Victor; van Strijp, Jos A. G.
ABSTRACT Staphylococcus aureus expresses a panel of cell wall-anchored adhesins, including proteins belonging to the microbial surface components recognizing adhesive matrix molecule (MSCRAMM) family, exemplified by the serine-aspartate repeat protein D (SdrD), which serve key roles in colonization and infection. Deletion of sdrD from S. aureus subsp. aureus strain NCTC8325-4 attenuated bacterial survival in human whole blood ex vivo, which was associated with increased killing by human neutrophils. Remarkably, SdrD was able to inhibit innate immune-mediated bacterial killing independently of other S. aureus proteins, since addition of recombinant SdrD protein and heterologous expression of SdrD in Lactococcus lactis promoted bacterial survival in human blood. SdrD contributes to bacterial virulence in vivo, since fewer S. aureus subsp. aureus NCTC8325-4 ΔsdrD bacteria than bacteria of the parent strain were recovered from blood and several organs using a murine intravenous infection model. Collectively, our findings reveal a new property of SdrD as an important key contributor to S. aureus survival and the ability to escape the innate immune system in blood. PMID:27795358
Johler, Sophia; Stephan, Roger; Althaus, Denise; Ehling-Schulz, Monika; Grunert, Tom
Staphylococcus aureus causes a variety of serious illnesses in humans and animals. Subtyping of S. aureus isolates plays a crucial role in epidemiological investigations. Metabolic fingerprinting by Fourier-transform infrared (FTIR) spectroscopy is commonly used to identify microbes at species as well as subspecies level. In this study, we aimed to assess the suitability of FTIR spectroscopy as a tool for S. aureus subtyping. To this end, we compared the subtyping performance of FTIR spectroscopy to other subtyping methods such as pulsed field gel electrophoresis (PFGE) and spa typing in a blinded experimental setup and investigated the ability of FTIR spectroscopy for identifying S. aureus clonal complexes (CC). A total of 70 S. aureus strains from human, animal, and food sources were selected, for which clonal complexes and a unique virulence and resistance gene pattern had been determined by DNA microarray analysis. FTIR spectral analysis resulted in high discriminatory power similar as obtained by spa typing and PFGE. High directional concordance was found between FTIR spectroscopy based subtypes and capsular polysaccharide expression detected by FTIR spectroscopy and the cap specific locus, reflecting strain specific expression of capsular polysaccharides and/or other surface glycopolymers, such as wall teichoic acid, peptidoglycane, and lipoteichoic acid. Supervised chemometrics showed only limited possibilities for differentiation of S. aureus CC by FTIR spectroscopy with the exception of CC45 and CC705. In conclusion, FTIR spectroscopy represents a valuable tool for S. aureus subtyping, which complements current molecular and proteomic strain typing.
Full Text Available Gram-negative bacteria produce outer membrane vesicles that play a role in the delivery of virulence factors to host cells. However, little is known about the membrane-derived vesicles (MVs produced by gram-positive bacteria. The present study examined the production of MVs from Staphylococcus aureus and investigated the delivery of MVs to host cells and subsequent cytotoxicity. Four S. aureus strains tested, two type strains and two clinical isolates, produced spherical nanovesicles during in vitro culture. MVs were also produced during in vivo infection of a clinical S. aureus isolate in a mouse pneumonia model. Proteomic analysis showed that 143 different proteins were identified in the S. aureus-derived MVs. S. aureus MVs were interacted with the plasma membrane of host cells via a cholesterol-rich membrane microdomain and then delivered their component protein A to host cells within 30 min. Intact S. aureus MVs induced apoptosis of HEp-2 cells in a dose-dependent manner, whereas lysed MVs neither delivered their component into the cytosol of host cells nor induced cytotoxicity. In conclusion, this study is the first report that S. aureus MVs are an important vehicle for delivery of bacterial effector molecules to host cells.
Marilyn M Ninan
Full Text Available We report a case of Shigella flexneri serotype-2 causing bacteremia in an elderly gentleman with uncontrolled diabetes mellitus, who had no other apparent risk factors. Antibiotic susceptibility testing revealed that the organism was a multidrug resistant extended spectrum beta-lactamase producing straian, which was confirmed by molecular characterization. This rare case alerts both the clinician and microbiologist to a previously unaddressed risk factor of Shigella spp. causing bacteremia, as well as emerging resistant strains that are on the rise in immunocompromised patients.
Friis-Møller, Alice; Lemming, L E; Valerius, Niels Henrik
Francisella philomiragia is a rare gram-negative, halophilic coccobacillus with bizarre spherical forms on primary isolation. A case of F. philomiragia bacteremia in a 24-year-old patient with chronic granulomatous disease is reported. Identification of F. philomiragia was problematic with conven......Francisella philomiragia is a rare gram-negative, halophilic coccobacillus with bizarre spherical forms on primary isolation. A case of F. philomiragia bacteremia in a 24-year-old patient with chronic granulomatous disease is reported. Identification of F. philomiragia was problematic...
Full Text Available Staphylococcus aureus (S. aureus infections are important because of their increasing frequency, resistance to antibiotics, and high associated rates of disabilities and deaths. We examined the incidence and correlates of S. aureus infections following 219,958 major surgical procedures in a 5% random sample of fee-for-service Medicare beneficiaries from 2004-2007. Of these surgical patients, 0.3% had S. aureus infections during the hospitalizations when index surgical procedures were performed; and 1.7% and 2.3%, respectively, were hospitalized with infections within 60 days or 180 days following admissions for index surgeries. S. aureus infections occurred within 180 days in 1.9% of patients following coronary artery bypass graft surgery, 2.3% following hip surgery, and 5.9% following gastric or esophageal surgery. Of patients first hospitalized with any major infection reported during the first 180 days after index surgery, 15% of infections were due to S. aureus, 18% to other documented organisms, and no specific organism was reported on claim forms in 67%. Patient-level predictors of S. aureus infections included transfer from skilled nursing facilities or chronic hospitals and comorbid conditions (e.g., diabetes, congestive heart failure, chronic obstructive pulmonary disease, and chronic renal disease. In a logarithmic regression, elective index admissions with S. aureus infection stayed 130% longer than comparable patients without that infection. Within 180 days of the index surgery, 23.9% of patients with S. aureus infection and 10.6% of patients without this infection had died. In a multivariate logistic regression of death within 180 days of admission for the index surgery with adjustment for demographics, co-morbidities, and other risks, S. aureus was associated with a 42% excess risk of death. Due to incomplete documentation of organisms in Medicare claims, these statistics may underestimate the magnitude of S. aureus infection
STAPHYLOCOCCUS AUREUS , CHROMOSOMES), (*CHROMOSOMES, MAPPING), NITROSO COMPOUNDS, GUANIDINES, GENETICS, MUTATIONS, DRUGS, TOLERANCES(PHYSIOLOGY), TEST METHODS, DEOXYRIBONUCLEIC ACIDS, INHIBITION, RESISTANCE(BIOLOGY).
Sandra Davi Traverso; Leonardo da Cunha; Joaquim César Teixeira Fernandes; Alexandre Paulino Loretti; Adriana Rhoden; Elsio Wunder Jr.; David Driemeier
Em uma criação composta por 1800 coelhos, 33% das matrizes apresentaram mastite e lesões cutâneas crostosas e purulentas. Estes animais apresentavam-se entre 10 a- 12 meses de idade e em segunda parição. Quinze coelhos afetados foram sacrificados e necropsiados. Na necropsia, além das lesões cutâneas haviam microabscessos em diversos órgãos. Das amostras coletadas isolou-se Staphylococcus aureus subesp. aureus. S. aureus subesp. aureus também foi isolado de "swab" nasal coletado do tratador e...
Li Hongyun; Yao Yongming; Shi Zhiguo; Dong Ning; Yu Yan; Lu Lianrong; Sheng Zhiyong
Objective: It has been demonstrated that biopterin, an essential cofactor of nitric oxide synthase (NOS), plays an important role in the pathogenesis of endotoxin-induced shock, yet its biological significance in gram-positive sepsis remains unclear. In this study, we adopted a rat model of postburn Staphylococcus aureus (S.aureus) sepsis to observe the time course and tissue distribution of biopterin in postburn S. aureus infection, and to investigate its potential role in the pathogenesis of gram-positive sepsis. Wistar rats were inflicted with a 20% total body surface area (TBSA) full-chickness scald injury followed by S. aureus challenge, then guanosine triphosphatecyclohydrolase I (GTP-CHI) mRNA expression and biopterin levels in liver, kidneys, lungs and heart were determined at 0. 5, 2, 6, 12 and 24 hours after S. aureus challenge. We found that after S. aureus challenge, GTP-CHI gene expressions and biopterin levels were markedly up-regulated in various tissues, and remained at high values up to 24 hours (P＜ 0. 05-0.01). Meanwhile, the organ function indexes, including serum alanine amimotransferase (ALT), aspartate aminotransferase (AST), creatinine (Cr), MB isoenzyme of creatine kinase (CK-MB), levels and pulmonary myeloperoxidase (MPO) activities significantly increased at 24 hours postburn, and the multiple organ dysfunction was aggravated by S. aureus challenge. Moreover, it was shown that cardiac GTP-CHI mRNA expression and renal BH4levels were positively correlated with CK-MB and Cr (r=0. 892, P=0. 0012 and r=0. 9423,P=0.0015, respectively). Conclusion: These results suggested that thermal injury combined with S. aureus challenge could induce de novo biosynthesis of biopterin, which acts as the most important cofactor of iNOS, might play a role in the development of multiple organ dysfunction syndrome secondary to postburn sepsis.
Sørensen Henrik T
Full Text Available Abstract Background Comparison of mortality among patients with positive and negative blood cultures may indicate the contribution of bacteremia to mortality. This study (1 compared mortality among patients with community-acquired bacteremia with mortality among patients with negative blood cultures and (2 determined the effects of bacteremia type and comorbidity level on mortality among patients with positive blood cultures. Methods This cohort study included 29,273 adults with blood cultures performed within the first 2 days following hospital admission to an internal medical ward in northern Denmark during 1995-2006. We computed product limit estimates and used Cox regression to compute adjusted mortality rate ratios (MRRs within 0-2, 3-7, 8-30, and 31-180 days following admission for bacteremia patients compared to culture-negative patients. Results Mortality in 2,648 bacteremic patients and 26,625 culture-negative patients was 4.8% vs. 2.0% 0-2 days after admission, 3.7% vs. 2.7% 3-7 days after admission, 5.6% vs. 5.1% 8-30 days after admission, and 9.7% vs. 8.7% 31-180 days after admission, corresponding to adjusted MRRs of 1.9 (95% confidence interval (CI: 1.6-2.2, 1.1 (95% CI: 0.9-1.5, 0.9 (95% CI: 0.8-1.1, and 1.0 (95% CI: 0.8-1.1, respectively. Mortality was higher among patients with Gram-positive (adjusted 0-2-day MRR 1.9, 95% CI: 1.6-2.2 and polymicrobial bacteremia (adjusted 0-2-day MRR 3.5, 95% CI: 2.2-5.5 than among patients with Gram-negative bacteremia (adjusted 0-2-day MRR 1.5, 95% CI 1.2-2.0. After the first 2 days, patients with Gram-negative bacteremia had the same risk of dying as culture-negative patients (adjusted MRR 0.8, 95% CI: 0.5-1.1. Only patients with polymicrobial bacteremia had increased mortality within 31-180 days following admission (adjusted MRR 1.3, 95% CI: 0.8-2.1 compared to culture-negative patients. The association between blood culture status and mortality did not differ substantially by level of
Felicio, Bruna A; Pinto, Maximiliano S; Oliveira, Francielly S; Lempk, Marcus W; Pires, Ana Clarissa S; Lelis, Carini A
The aim of this work was to evaluate the effects of nisin on in vitro and in situ Staphylococcus aureus counts. For in vitro experiment, milk was inoculated with 5.0 log cfu·mL(-1) of S. aureus and nisin was added at concentrations of 0, 100, 200, 400, and 500 IU mL(-1). The main effect of the bacteriocin was lag phase extension from 0h, for 0 and 100 IU·mL(-1) to 8h, when 200, 400, and 500 IU·mL(-1) of nisin were used; however, log phase was not affected. Microbial growth rate was found to be exponential and around 0.11 log cfu·mL(-1)·h(-1) for all treatments. For in situ experiments, 0, 400, and 500 IU·mL(-1) of nisin were directly added to pasteurized milk previously inoculated with 5.0 log cfu·g(-1) of S. aureus. Milk, curd, and whey were analyzed to S. aureus counts. Nisin at concentration of 500 IU·mL(-1) was able to reduce S. aureus count in curd and whey, demonstrating nisin partition between both phases. Throughout storage at 4°C, S. aureus count increased for all treatments, but the bacterial grew slower when nisin was added in both concentrations, maintaining S. aureus count about 1.5 log cycles lower than the control, despite abusive initial S. aureus count. Therefore, nisin seems to play an important role in reducing S. aureus initial count in cheese made with highly contaminated milk. Nisin showed potential to be used as an additional, important hurdle to improve Minas Frescal cheese safety, without replacing good manufacturing practices.
Orth, H.; Dreyer, Z.S.; Makgotlho, E.; Oosthuysen, W.; Sinha, B.; Wasserman, E.
To elucidate the local epidemiology of Staphylococcus aureus bacteraemia, we characterised blood culture isolates using molecular methods and prospectively collected clinical data to determine the occurrence of community-acquired, methicillinresistant S. aureus (MRSA). Consecutive S. aureus blood cu
Full Text Available Clinical disease caused by Empedobacter brevis (E. brevis is very rare. We report the first case of E. brevis bacteremia in a patient with HIV and review the current literature. A 69-year-old man with human immunodeficiency virus (HIV and CD4 count of 319 presented with chief complaints of black tarry stools, nausea and vomiting for 2 days. Physical exam was significant for abdominal pain on palpation with no rebound or guarding. His total leukocyte count was 32,000 cells/μL with 82% neutrophils and 9% bands. Emergent colonoscopy and endoscopic esophagogastroduodenoscopy showed esophageal candidiasis, a nonbleeding gastric ulcer, and diverticulosis. Blood cultures drawn on days 1, 2, and 3 of hospitalization grew E. brevis. Patient improved with intravenous antibiotics. This case is unusual, raising the possibility of gastrointestinal colonization as a source of the patient’s bacteremia. In conclusion, E. brevis is an emerging pathogen that can cause serious health care associated infections.
Eleftheriadis, T; Liakopoulos, V; Leivaditis, K; Antoniadi, G; Stefanidis, I
Hemodialysis (HD) patients are particularly predisposed to infections. It seems that the HD procedure per se as well as disturbances in both innate and adaptive immunity significantly contribute to this susceptibility. Infections are the major cause of morbidity and the second cause of death following cardiovascular events in HD patients. Episodes of bacteremia and pneumonia account for the majority of severe infections in this population. In addition to these bacterial infections another common problem in HD units is the blood transmitted viral infections, particularly infections caused by hepatitis B virus, hepatitis C virus and Human immunodeficiency virus. A number of safety concerns exist for limiting the spread of these viral infections among HD patients and the staff of the unit. The aim of the present review is to present in a concise albeit practical form the difficult aspect of infections in HD. For practical reasons the review is separated in two parts. The present first part covers bacteremia and respiratory infections, while the second part will cover blood transmitted viral infections. PMID:21607029
Taniyama, Daisuke; Abe, Yoshihiko; Sakai, Tetsuya; Kikuchi, Takahide; Takahashi, Takashi
Streptococcus canis (Sc) is a zoonotic pathogen that is transferred mainly from companion animals to humans. One of the major virulence factors in Sc is the M-like protein encoded by the scm gene, which is involved in anti-phagocytic activities, as well as the recruitment of plasminogen to the bacterial surface in cooperation with enolase, and the consequent enhancement of bacterial transmigration and survival. This is the first reported human case of uncomplicated bacteremia following a dog bite, caused by Streptococcus canis harboring the scm gene. The similarity of the 16S rRNA from the infecting species to that of the Sc type strain, as well as the amplification of the species-specific cfg gene, encoding a co-hemolysin, was used to confirm the species identity. Furthermore, the isolate was confirmed as sequence type 9. The partial scm gene sequence harbored by the isolate was closely related to those of other two Sc strains. While this isolate did not possess the erm(A), erm(B), or mef(A), macrolide/lincosamide resistance genes, it was not susceptible to azithromycin: its susceptibility was intermediate. Even though human Sc bacteremia is rare, clinicians should be aware of this microorganism, as well as Pasteurella sp., Prevotella sp., and Capnocytophaga sp., when examining and treating patients with fever who maintain close contact with companion animals.
Lachara V. Livingston
Full Text Available Streptococcus intermedius is a member of the Streptococcus anginosus group of bacteria. This group is part of the normal flora of the oropharynx, genitourinary, and gastrointestinal tracts; however, they have been known to cause a variety of purulent infections including meningitis, endocarditis, and abscesses, even in immunocompetent hosts. In particular, S. intermedius has been associated with the development of liver and brain abscesses. There have been several case reports of S. intermedius liver abscesses with active periodontal infection. To our knowledge, however, there has not been a case following a routine dental procedure. In fact, the development of liver abscesses secondary to dental procedures is very rare in general, and there are only a few case reports in the literature describing this in relation to any pathogen. We present a rare case of S. intermedius bacteremia and liver abscess following a dental cleaning. This case serves to further emphasize that even routine dental procedures can place a patient at risk of the development of bacteremia and liver abscesses. For this reason, the clinician must be sure to perform a detailed history and careful examination. Timely diagnosis of pyogenic liver abscesses is vital, as they are typically fatal if left untreated.
Livingston, Lachara V; Perez-Colon, Elimarys
Streptococcus intermedius is a member of the Streptococcus anginosus group of bacteria. This group is part of the normal flora of the oropharynx, genitourinary, and gastrointestinal tracts; however, they have been known to cause a variety of purulent infections including meningitis, endocarditis, and abscesses, even in immunocompetent hosts. In particular, S. intermedius has been associated with the development of liver and brain abscesses. There have been several case reports of S. intermedius liver abscesses with active periodontal infection. To our knowledge, however, there has not been a case following a routine dental procedure. In fact, the development of liver abscesses secondary to dental procedures is very rare in general, and there are only a few case reports in the literature describing this in relation to any pathogen. We present a rare case of S. intermedius bacteremia and liver abscess following a dental cleaning. This case serves to further emphasize that even routine dental procedures can place a patient at risk of the development of bacteremia and liver abscesses. For this reason, the clinician must be sure to perform a detailed history and careful examination. Timely diagnosis of pyogenic liver abscesses is vital, as they are typically fatal if left untreated.
Velusamy, Senthil Kumar; Fine, Daniel H; Velliyagounder, Kabilan
Streptococcus mutans is the primary agent of dental caries, which is often detected in transient bacteremia. Lactoferrin is a multifunctional glycoprotein showing antibacterial activities against several Streptococcus species. We reported here the prophylactic effect of human lactoferrin (hLF) in a lactoferrin knockout mouse (LFKO-/-) bacteremic model. The hLF treatment significantly cleared S. mutans from the blood and organs of bacteremic mice when compared to the non-hLF treated mice. Further, analysis of serum cytokines, spleen and liver cytokine mRNA levels revealed that hLF prophylaxis modulates their release differently when compared to the non-hLF treated group. C-reactive protein level (P = 0.003) also decreased following hLF prophylaxis in S. mutans induced bacteremic mice. Additional quantitative RT-PCR analysis revealed that hLF prophylaxis significantly decreased the expression level of IFN-γ, TNF-α, IL-1β, IL-6, MPO and iNOS in spleen and liver. These results suggested that the hLF protects the host against S. mutans-induced experimental bacteremia.
Vazquez, F; Mendez, F J; Perez, F; Mendoza, M C
Anaerobic bacteremia (116 cases) represented 5.4% of the total cases of bacteremia in the Hospital Nuestra Señora de Covadonga of Oviedo, Spain, during a five-year period (1981-1985). Microbiologic data for all 116 cases and clinical data for 63 patients were analyzed. A total of 129 isolates were identified as gram-negative bacilli (45.7%), gram-positive bacilli (38.0%), gram-positive cocci (14.0%), and gram-negative cocci (2.3%). Bacteroides fragilis and Clostridium perfringens were the most frequently occurring species. Anaerobic polymicrobial infection was detected in 21 patients. The most relevant clinical features were fever (79%), metastatic abscesses (33%), anemia (27%), septic shock (25%), and disseminated intravascular coagulation (6%). The overall mortality rate was 25.4%, and the factors associated with a poor prognosis were age over 60 years, lack of adequate surgical treatment, severe underlying disease, metastatic foci, and polymicrobial and/or nosocomial infection.
Full Text Available OBJECTIVE: We report an outbreak of Achromobacter xylosoxidans at a neonatal intensive care unit. We aimed to present clinical, laboratory and treatment data of the patients. Materials and METHODS: All consecutive episodes of bacteremia due to A. xylosoxidans at our neonatal intensive care unit, beginning with the index case detected at November 2009 until cessation of the outbreak in April 2010, were evaluated retrospectively. RESULTS: Thirty-four episodes of bacteremia occurred in 22 neonates during a 6-month period. Among the affected, 90% were preterm newborns with gestational age of 32 weeks or less and 60% had birth weight of 1000 g or less. Endotracheal intubation, intravenous catheter use, total parenteral nutrition and prolonged antibiotic therapy were the predisposing conditions. Presenting features were abdominal distention, thrombocytopenia and neutropenia. The mortality rate was 13.6% and the majority of isolates were susceptible to piperacillin-tazobactam, carbapenems and trimethoprim-sulfametoxazole, and resistant to gentamycin. More than half were breakthrough infections. Despite intensive efforts to control the outbreak by standard methods of hand hygiene, patient screening and isolation, containment could be achieved only after the neonatal intensive care unit was relocated. The investigation was not able to single out the source of the outbreak. CONCLUSION: A. xylosoxidans has the potential to cause serious infections in premature babies. More studies are needed to determine the importance of different sources of infection in hospital units.
Syed, Adnan K; Ghosh, Sudeshna; Love, Nancy G; Boles, Blaise R
The biocide triclosan is used in many personal care products, including toothpastes, soaps, clothing, and medical equipment. Consequently, it is present as a contaminant in the environment and has been detected in some human fluids, including serum, urine, and milk. Staphylococcus aureus is an opportunistic pathogen that colonizes the noses and throats of approximately 30% of the population. Colonization with S. aureus is known to be a risk factor for several types of infection. Here we demonstrate that triclosan is commonly found in the nasal secretions of healthy adults and the presence of triclosan trends positively with nasal colonization by S. aureus. We demonstrate that triclosan can promote the binding of S. aureus to host proteins such as collagen, fibronectin, and keratin, as well as inanimate surfaces such as plastic and glass. Lastly, triclosan-exposed rats are more susceptible to nasal colonization with S. aureus. These data reveal a novel factor that influences the ability of S. aureus to bind surfaces and alters S. aureus nasal colonization. IMPORTANCE Triclosan has been used as a biocide for over 40 years, but the broader effects that it has on the human microbiome have not been investigated. We demonstrate that triclosan is present in nasal secretions of a large portion of a test population and its presence correlates with Staphylococcus aureus nasal colonization. Triclosan also promotes the binding of S. aureus to human proteins and increases the susceptibility of rats to nasal colonization by S. aureus. These findings are significant because S. aureus colonization is a known risk factor for the development of several types of infections. Our data demonstrate the unintended consequences of unregulated triclosan use and contribute to the growing body of research demonstrating inadvertent effects of triclosan on the environment and human health.
Guajardo-Lara, Claudia Elena; Saldaña-Ramírez, Martha Idalia; Ayala-Gaytán, Juan Jacobo; Valdovinos-Chávez, Salvador Bruno
Introducción: la frecuencia de la septicemia va en aumento y su mortalidad es alta; por lo tanto, su detección, la identificación del microorganismo causal y su susceptibilidad son perentorias. Metodos: se revisaron los registros de 4110 botellas de cultivo de sangre obtenida de enero de 2013 a julio de 2014 de pacientes adultos en un hospital privado de tercer nivel. Resultados: se observó crecimiento de microorganismos en 559 cultivos (12.6 %). En 2648 hemocultivos (60 %) inoculados en pares de frascos uno con medio aeróbico y el otro anaeróbico (1324 sets), se detectó crecimiento en 182 frascos a los que les fueron inoculadas las muestras tomadas al mismo tiempo a 135 pacientes (13.7 %). En 86 pares de frascos con las muestras de 54 pacientes (40 %), el crecimiento solamente se dio en el frasco aeróbico (47.5 %); en 24 pares de frascos (13.19 %) tomados a 21 pacientes (15.5 %, p < 0.05), solamente hubo crecimiento en el frasco anaeróbico. En los hemocultivos de 32 de 60 pacientes con crecimiento en ambos frascos (53 %), el crecimiento se detectó primero en el frasco anaeróbico. Conclusiones: los hemocultivos anaeróbicos tienen una utilidad baja para la detección de bacteriemias por anaerobios estrictos; no obstante, en el 15.55 % de los pacientes estuvo presente el riesgo de pasar por alto la presencia de bacteriemia, y en 53 % de los pacientes con hemocultivos positivos, el diagnóstico de bacteriemia pudo establecerse de manera más temprana, lo que permitió anticipar con mejor precisión la toma de decisiones.
Conclusions: In accordance with our previous study, our results have demonstrated the inferiority of flomoxef to carbapenems in the treatment of HD access-related ESBL-Kp bacteremia and provide an insight into the possibility of using ertapenem rather than flomoxef as an initial or de-escalating therapy for infections caused by ESBL-producing bacteria.
Giufrè, Maria; Cardines, Rita; Degl'Innocenti, Roberto; Cerquetti, Marina
We report the first case of neonatal bacteremia caused by a "Haemophilus quentini" isolate in Italy. The isolate was differentiated from H. influenzae by 16S rRNA sequencing and was characterized by comparison with the wild-type "H. quentini" CCUG 36167. Both isolates carried substitutions in penicillin-binding protein 3 but were susceptible to aminopenicillins.
VanWagoner, Timothy M.; Seale, Thomas W.; Mussa, Huda J.; Cole, Brett K.; Whitby, Paul W.; Stull, Terrence L.
Haemophilus influenzae is an important cause of invasive disease. The infant rat is the accepted model of invasive H. influenzae disease. Here, we report the genome sequences of six nontypeable H. influenzae strains that establish bacteremia in the infant rat. PMID:26404588
Full Text Available Campylobacter fetus bacteremia is rare and occurs mainly in patients with immunosuppression. This infection, which often involves secondary localizations has already been reported in some primary humoral immune deficiencies. We describe three cases of severe infection due to C. fetus with cellulitis at presentation, but without any gastrointestinal symptoms, occurring in patients with acquired hypogammaglobulinemia.
Relich, Ryan F; Humphries, Romney M; Mattison, H Reid; Miles, Jessica E; Simpson, Edward R; Corbett, Ian J; Schmitt, Bryan H; May, M
Francisella philomiragia is a very uncommon pathogen of humans. Diseases caused by it are protean and have been reported largely in near-drowning victims and those with chronic granulomatous disease. We present a case of F. philomiragia pneumonia with peripheral edema and bacteremia in a renal transplant patient and review the diverse reports of F. philomiragia infections.
During six months, we obtained Enterobacteriaceae isolates from patients with Gram-negative bacteremia at a 1250-bed teaching hospital in St. Louis, Missouri, and compared carbapenem susceptibility with the presence of blaKPC, a transferable carbapenemase gene. Three (1.2%) out of 243 isolates were ...
David Michael Z
Full Text Available Abstract Kocuria species are unusual human pathogens isolated most commonly from immunocompromised hosts, such as transplant recipients and cancer patients undergoing chemotherapy, or from patients with chronic medical conditions. A case of catheter-related bacteremia with pulmonary septic emboli in a pregnant adult female without chronic medical conditions is described. A review of other reported Kocuria infections is provided.
Vos, F.J.; Bleeker-Rovers, C.P.; Sturm, P.D.J.; Krabbe, P.F.M.; Dijk, A.P.J. van; Cuijpers, M.L.H.; Adang, E.M.M.; Wanten, G.J.A.; Kullberg, B.J.; Oyen, W.J.G.
The timely detection of metastatic infectious foci in gram-positive bacteremia is crucial, because these foci often require prolonged antibiotic treatment or drainage. The diagnosis of metastatic infectious foci is difficult because localizing symptoms are often absent. We investigated whether (18)F
Vos, Fidel J; Bleeker-Rovers, Chantal P; Sturm, Patrick D; Krabbe, Paul F M; van Dijk, Arie P J; Cuijpers, Maria L H; Adang, Eddy M M; Wanten, Geert J A; Kullberg, Bart-Jan; Oyen, Wim J G
UNLABELLED: The timely detection of metastatic infectious foci in gram-positive bacteremia is crucial, because these foci often require prolonged antibiotic treatment or drainage. The diagnosis of metastatic infectious foci is difficult because localizing symptoms are often absent. We investigated w
Vos, F.J.; Bleeker-Rovers, C.P.; Sturm, P.D.; Krabbe, P.F.M.; Van Dijk, A. P. J.; Cuijpers, M.L.H.; Adang, E.M.M.; Wanten, G.J.A.; Kullberg, B.J.; Oyen, W.J.G.
The timely detection of metastatic infectious foci in gram-positive bacteremia is crucial, because these foci often require prolonged antibiotic treatment or drainage. The diagnosis of metastatic infectious foci is difficult because localizing symptoms are often absent. We investigated whether (18)F
de Jager, C.P.C.; van Wijk, P.T.I.; Mathoera, R.B.; de Jongh-Leuvenink, J.; van der Poll, T.; Wever, P.C.
Introduction: Absolute lymphocytopenia has been reported as a predictor of bacteremia in medical emergencies. Likewise, the neutrophil-lymphocyte count ratio (NLCR) has been shown a simple promising method to evaluate systemic inflammation in critically ill patients. Methods: We retrospectively eval
F.N.J. Frakking (Florine N.); W.C. Rottier (Wouter); J.W. Dorigo-Zetsma; J.M. van Hattem (Jarne); B.C. van Hees (Babette); J.A.J.W. Kluytmans (Jan); S.P.M. Lutgens (Suzanne P.); J.M. Prins (Jan); S.F. Thijsen (Steven); A. Verbon (Annelies); B.J.M. Vlaminckx (Bart J.); J.W.C. Stuart (James W. Cohen); M.A. Leverstein-Van Hall (Maurine); M.J.M. Bonten (Marc)
textabstractWe studied clinical characteristics, appropriateness of initial antibiotic treatment, and other factors associated with day 30 mortality in patients with bacteremia caused by extended-spectrum-β-lactamase (ESBL)-producing bacteria in eight Dutch hospitals. Retrospectively, information wa
Miedema, Karin G. E.; Winter, Rik H. L. J.; Ammann, Roland A.; Droz, Sara; Spanjaard, Lodewijk; de Bont, Eveline S. J. M.; Kamps, Willem A.; van de Wetering, Marianne D.; Tissing, Wim J. E.
Infections are a major cause of morbidity and mortality in pediatric cancer patients. The aim of this study was to establish the microbiological spectrum and the susceptibility patterns of bacteremia-causing bacteria in pediatric cancer patients with febrile neutropenia in relation to the use of pro
Li Mei Li; Qiang Zou; Guo You Li
A novel chromone,named chaetoaurin (1),along with six known chromone derivatives (2-7),was isolated from the ethyl acetate extract of a solid-state fermented culture of Chaetomium aureus.Their structures were elucidated by extensive spectral analysis.All of these compounds were reported from C.aureus for the first time.
N.J. Verkaik (Nelianne); O. Dauwalder (Olivier); K. Antri (Kenza); I. Boubekri (Ilhem); C.P. de Vogel (Corné); C. Badiou (Cédric); M. Bes (Michèle); F. Vandenesch (François); M. Tazir (Mohammed); H. Hooijkaas (Herbert); H.A. Verbrugh (Henri); A.F. van Belkum (Alex); J. Etienne (Jerome); G. Lina (Gérard); N. Ramdani-Bouguessa (Nadjia); W.J.B. van Wamel (Willem)
textabstractAB - BACKGROUND: Toxins are important Staphylococcus aureus virulence factors, but little is known about their immunogenicity during infection. Here, additional insight is generated. METHODS: Serum samples from 206 S. aureus-infected patients and 201 hospital-admitted control subjects we
Chen, Po-Lin; Tsai, Liang-Miin; Kan, Chung-Dann; Ko, Wen-Chien
Nontyphoid Salmonella (NTS) can cause invasive diseases in the elderly. Notably, the most feared complication of NTS bacteremia is endovascular infection. The risk factors for infected aortic aneurysm include old age and atherosclerosis. Extended use of antimicrobial therapy (> 2 weeks) for NTS bacteremia should be considered for those who demonstrate the risk factors for endovascular infection, even when a metastatic focus is clinically elusive. Herein, we report the case of a 75-year-old patient with diabetes mellitus, hypertension, chronic kidney disease, and myocardial infarction who died of an infected aortic aneurysm despite 3 weeks of antibiotic therapy that was administered to treat the initial NTS bacteremia.
HUANG Dao-zheng; MA Huan; WANG Shou-hong; WU Yan; QIN Tie-he; TAN Ning
Background Septic shock caused by bacteremia is a life-threatening infection whose prognosis is highly dependent on early recognition and appropriate treatment.Procalcitonin (PCT) has been shown to accurately and quickly distinguish bacteremia from noninfectious inflammatory states in critically severe patients.However,the extent of PCT magnitude elevation according to the Gram stain result in elderly patients with coronary heart disease (CHD) at the onset of septic shock caused by bacteremia varies,and has not been clearly elucidated.Methods The medical records of advanced age (non-neutropenic) patient with CHD and septic shock between Mar 2013 and Jun 2015 who had bacteremia caused by either Gram-positive (GP) bacteria or Gram-negative (GN) bacteria were reviewed,and the levels of PCT,C-reactive (CRP) protein and white blood cells count (WBC) in both groups were analyzed.Results 75 episodes of either GN bacteremia (n =40) or GP bacteremia (n =35) were enrolled.PCT levels were found to be markedly higher in patients with GN bacteremia than in those with GP bacteremia [(8.93 ± 17.58) vs.(64.42 ± 58.56) ng/L (P ＜ 0.001)],whereas there was no significant difference in CRP and WBC (P ＞ 0.05).Moreover,a high PCT level was found to be independently associated with GN bacteremia in this study population.A PCT level of 19.69 ng/mL yielded a 72.5％ sensitivity,a 91.4％ specificity,an 8.43 positive likelihood ratio and a 0.30 negative likelihood ratio for GN-related bacteremia in the study cohort [AUROCC =0.870 (0.041),95％ CI (0.790-0.949)].Conclusion In an elderly patient (non-neutropenic)with CHD and septic shock,GN bacteremia could be associated with higher PCT values than those found in GP bacteremia (PCT ＞ 19.69 ng/mL).
目的 了解住院菌血症患者的临床特征和病原菌耐药情况,探讨菌血症的相关因素. 方法 对2010年7月～2012年7月住院菌血症患者的临床资料进行回顾性分析,以EXCEL及SPSS统计分析病原菌种类和药物敏感情况. 结果 收集1231例血培养标本,共分离病原菌174株,革兰阴性杆菌(G-杆菌)60.34％,革兰阳性球菌(G+球菌)33.90％,真菌5.74％;G-杆菌以大肠埃希菌和肺炎克雷伯菌为主,对亚胺培南和阿米卡星高度敏感,对氨苄西林高度耐药；G+球菌以溶血葡萄球菌和金黄色葡萄球菌为主,对万古霉素、替考拉宁、利奈唑胺、呋喃妥因、喹奴普汀-达福普汀、米诺环素全敏感,对青霉素高度耐药.医院获得性感染为39.0％,社区获得性感染61.0为％；有基础疾病者为81.8％；科室主要分布于肿瘤科、重症监护室(ICU).经过抗生素治疗,治愈及好转为87.0％、死亡为7.8％、未愈为5.2％.临床上97.4％有发热,常伴寒战症状. 结论 应根据分析结果选用最佳抗生素治疗菌血症患者,缩短治疗时间,减少细菌耐药性发生机会,提高菌血症的救治成功率.%Objective To understand the distribution and drug resistance of pathogens in bacteremia in Xuwen county Hospital,Guangdong.Methods The distribution of pathogens isolated and identified from bacteremia inpatients were analyzed and the resistance of the pathogens to antibiotics was tested from July 2010 and July 2012.Results Totally 174 bacterial strains were isolated from 1 231 blood samples,in which gram-negative bacillus occupied 60.34％,grand-positive cocci accounted for 33.90％ and,fungi 5.74％ ;The main G-bacillus were Escherichia coli and Klebsiella pneumoniae highly sensitive to imipenem and amikacin,but resistance highly to ampicillin;The main G+ cocci were Staphylococcus haemolyticus and Staphylococcus aureus sensitive to vancomycin,teicoplanin,linezolid,nitrofurantoin,Kui Nu tianeptine-dafoe Putin
In addition to its pivotal role in hemostasis, fibrinogen (Fg) and provisional fibrin matrices play important roles in inflammation and regulate innate immune responses by interacting with leukocytes. Efb (the extracellular fibrinogen-binding protein) is a secreted Staphylococcus aureus protein that...
Na, Manli; Jarneborn, Anders; Ali, Abukar; Welin, Amanda; Magnusson, Malin; Stokowska, Anna; Pekna, Marcela; Jin, Tao
The complement system plays an essential role in the innate immune response and protection against bacterial infections. However, detailed knowledge regarding the role of complement in Staphylococcus aureus septic arthritis is still largely missing. In this study, we elucidated the roles of selected complement proteins in S. aureus septic arthritis. Mice lacking the complement component 3 (C3(-/-)), complement factor B (fB(-/-)), and receptor for C3-derived anaphylatoxin C3a (C3aR(-/-)) and wild-type (WT) control mice were intravenously or intra-articularly inoculated with S. aureus strain Newman. The clinical course of septic arthritis, as well as histopathological and radiological changes in joints, was assessed. After intravenous inoculation, arthritis severity and frequency were significantly higher in C3(-/-)mice than in WT controls, whereas fB(-/-)mice displayed intermediate arthritis severity and frequency. This was in accordance with both histopathological and radiological findings. C3, but not fB, deficiency was associated with greater weight loss, more frequent kidney abscesses, and higher bacterial burden in kidneys. S. aureus opsonized with C3(-/-)sera displayed decreased uptake by mouse peritoneal macrophages compared with bacteria opsonized with WT or fB(-/-)sera. C3aR deficiency had no effect on the course of hematogenous S. aureus septic arthritis. We conclude that C3 deficiency increases susceptibility to hematogenous S. aureus septic arthritis and impairs host bacterial clearance, conceivably due to diminished opsonization and phagocytosis of S. aureus.
Full Text Available Louise Kruse Johansen, Henrik Elvang JensenDepartment of Veterinary Disease Biology, Faculty of Health and Medical Science, University of Copenhagen, Frederiksberg, DenmarkAbstract: Hematogenous osteomyelitis (HO, especially due to Staphylococcus aureus, is primarily reported in children and occurs when blood-borne bacteria settle in the metaphysis of a long bone and mediate an inflammatory response. The literature contains several reports on animal models aiming to simulate pediatric HO, in order to investigate the pathogenesis and for therapeutic use. In these models, osteomyelitis lesions develop subsequently to bacteremia, which can be induced by either intravenous or intra-arterial inoculation of bacteria. Intravenous inoculation is not optimal because of the ethical aspects of the extensive systemic reaction and the unpredictable identity of bones being infected. Also, intravenous inoculation often has to be combined with the induction of artificial bone necrosis in order to have macroscopic lesions. In contrast, models based on intra-arterial inoculation and subsequent development of local osteomyelitis, are the most accurate and predictable way to extrapolate to pediatric cases of HO. The most commonly used animal species for modeling of HO are rabbits, chickens, and mice, whereas, less frequently, dogs, rats, and pigs have been applied. The use of intra-arterial inoculation, without simultaneous artificial bone necrosis for the development of HO lesions has only been used in porcine models. Because of the similarity of human and porcine physiology, metabolic rate, and size, porcine models of HO are advantageous. Therefore, porcine models based on the intra-arterial induction of osteomyelitis are the most refined HO models.Keywords: hematogenous osteomyelitis, animal models, Staphylococcus aureus
Determinants of mortality in oncology patients colonized or infected with Staphylococcus aureus Determinantes de mortalidade em pacientes colonizados ou infectados por internados em um hospital do câncer. Staphylococcus aureus
Luiz Claudio Santos Thuler
Full Text Available Oxacillin-resistant Staphylococcus aureus (ORSA infection is an important cause of hospital morbidity and mortality. The objective of this study was to identify the main factors associated with death in patients colonized or infected with Staphylococcus aureus in a cancer center. A matched-pair case-control study enrolled all patients infected or colonized with ORSA (cases admitted to the Hospital do Câncer in Rio de Janeiro from 01/01/1992 to 12/31/1994. A control was defined as a patient hospitalized during the same period as the case-patients and colonized or infected with oxacillin-susceptible Staphylococcus aureus (OSSA. The study enrolled 95 cases and 95 controls. Patient distribution was similar for the two groups (p > or = 0.05 with respect to gender, underlying diseases, hospital transfer, prior infection, age, temperature, heart and respiratory rates, neutrophil count, and duration of hospitalization. Univariate analysis of putative risk factors associated with mortality showed the following significant variables: admission to the intensive care unit (ICU, presence of bacteremia, use of central venous catheter (CVC, ORSA colonization or infection, pneumonia, use of urinary catheter, primary lung infection, prior use of antibiotics, mucositis, and absence of cutaneous abscesses. Multivariate analysis showed a strong association between mortality and the following independent variables: admission to ICU (OR [odds ratio]=7.2, presence of Staphylococcus bacteremia (OR=6.8, presence of CVC (OR=5.3, and isolation of ORSA (OR=2.7. The study suggests a higher virulence of ORSA in comparison to OSSA in cancer patients.As infecções causadas por Staphylococcus aureus resistentes à oxacilina (ORSA são causas importantes de morbidade e mortalidade. O objetivo do estudo foi identificar os principais fatores associados à mortalidade em pacientes colonizados ou infectados por Staphylococcus aureus em um hospital de câncer. Foi realizado um
Full Text Available Acute bacterial meningitis has a low incidence (3/100,000 in the United States and yet high fatality rate (approximately 14–16% and classically presents as a triad of fever, neck stiffness, and altered mental status. However, less than half of patients with meningitis present with this classic triad. We present the clinical course of a patient who initially presented to the emergency department after overdosing on ibuprofen for what he described as back pain secondary to mechanical injury. However, the patient's condition quickly deteriorated: he developed tachycardia, mental status changes, was intubated due to respiratory distress, and then suffered an 8-minute PEA arrest before return of spontaneous circulation was achieved. After the patient was stabilized, in addition to the nonsteroidal anti-inflammatory drug (NSAID overdose Staphylococcus aureus meningitis, bacteremia, and pneumonia were diagnosed. We report this case to illustrate that the initial presentation of meningitis may be extremely unusual especially in the setting of NSAID overdose and the acutely decompensating patient. As the risk of adverse clinical outcomes increases with delays in appropriate antibiotic therapy, it is therefore crucial to recognize the many signs and symptoms of meningitis, typical and atypical, and quickly begin appropriate treatment.
Cojutti, Piergiorgio; Scarparo, Claudio; Sartor, Assunta; Coato, Paola; Rigoli, Roberto; Pea, Federico
A 5-year survey (2009-2013) of antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients with bloodstream infections was carried out in Northeast Italy. No upward creep of glycopeptides MICs was documented among 582 nonduplicate MRSA blood isolates, which were tested in accordance with broth microdilution and interpreted in accordance with EUCAST recommendations. Teicoplanin showed stably a lower MIC50 in comparison with vancomycin (0.25-0.5 versus 1 mg/L). The activities of newer anti-MRSA antibacterials stratified by glycopeptides MICs showed similar trends in MICs of either vancomycin or teicoplanin with those of daptomycin, linezolid, and tigecycline. We hypothesize that in centers with different distribution of glycopeptides MICs, downward for teicoplanin and upward for vancomycin, teicoplanin could be a more effective alternative to vancomycin for empirical treatment of MRSA-related bacteremia.
Full Text Available Pediatric invasive community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA infection is very serious and occasionally fatal. This infectious disease is still a relatively rare and unfamiliar infectious disease in Japan. We report a positive outcome in a 23-month-old Japanese girl with meningitis, osteomyelitis, fasciitis, necrotizing pneumonia, urinary tract infection, and bacteremia due to CA-MRSA treated with linezolid. PCR testing of the CA-MRSA strain was positive for PVL and staphylococcal enterotoxin b and negative for ACME. SCC mec was type IVa. This case underscores the selection of effective combinations of antimicrobial agents for its treatment. We need to be aware of invasive CA-MRSA infection, which rapidly progresses with a serious clinical course, because the incidence of the disease may be increasing in Japan.
Full Text Available Noni (Morinda citrifolia Increase Immune Response in Mice (Mus musculus Infected Staphylococcus aureus. Infection disease caused by bacteria is one of the illness in several developing countries including in Indonesia, with high mortality rate. Infection of S. aureus as the cause of problem resistance for antibiotic or multi drug resistance are giving the therapy of drug itself with change to medical herbal. The aim of this study is known the role of M.citrifolia extract to increase immune response of mice with infectioned of S. aureus. Mice were divided into two groups there are Non Infection and infection. Non Infection is without S. aureus and than infection has S. aureus. The each groups are including control, dose 1 (25 mg/kg BW, dose 2 (100 mg/kg BW, and dose 3 (300 mg/kg BW. Relative number of lymphocyte T cell (CD4+ subsets was measured using the BD FACSCaliburTM Flowcytometer. Data were analyzed using Analysis of Varians (p<0,05 and using SPSS 16 for windows. The result showed that administration of M. citrifolia crude extract in non infection groups was significantly increase the relative amounts T cell subsets (CD4+. Noni fruit extract can used as prevention therapy on infection disease of S. aureus bacteria because it contains active compounds that are anti-inflammation
Popov, Lauren M; Marceau, Caleb D; Starkl, Philipp M; Lumb, Jennifer H; Shah, Jimit; Guerrera, Diego; Cooper, Rachel L; Merakou, Christina; Bouley, Donna M; Meng, Wenxiang; Kiyonari, Hiroshi; Takeichi, Masatoshi; Galli, Stephen J; Bagnoli, Fabio; Citi, Sandra; Carette, Jan E; Amieva, Manuel R
Staphylococcus aureus is both a transient skin colonizer and a formidable human pathogen, ranking among the leading causes of skin and soft tissue infections as well as severe pneumonia. The secreted bacterial α-toxin is essential for S. aureus virulence in these epithelial diseases. To discover host cellular factors required for α-toxin cytotoxicity, we conducted a genetic screen using mutagenized haploid human cells. Our screen identified a cytoplasmic member of the adherens junctions, plekstrin-homology domain containing protein 7 (PLEKHA7), as the second most significantly enriched gene after the known α-toxin receptor, a disintegrin and metalloprotease 10 (ADAM10). Here we report a new, unexpected role for PLEKHA7 and several components of cellular adherens junctions in controlling susceptibility to S. aureus α-toxin. We find that despite being injured by α-toxin pore formation, PLEKHA7 knockout cells recover after intoxication. By infecting PLEKHA7(-/-) mice with methicillin-resistant S. aureus USA300 LAC strain, we demonstrate that this junctional protein controls disease severity in both skin infection and lethal S. aureus pneumonia. Our results suggest that adherens junctions actively control cellular responses to a potent pore-forming bacterial toxin and identify PLEKHA7 as a potential nonessential host target to reduce S. aureus virulence during epithelial infections.
Full Text Available Staphylococcus aureus is an important pathogen of humans and livestock. It causes a diverse array of diseases, ranging from relatively harmless localized skin infections to life-threatening systemic conditions. Among multiple virulence factors, staphylococci secrete several exotoxins directly associated with particular disease symptoms. These include toxic shock syndrome toxin 1 (TSST-1, enterotoxins, and exfoliative toxins (ETs. The latter are particularly interesting as the sole agents responsible for staphylococcal scalded skin syndrome (SSSS, a disease predominantly affecting infants and characterized by the loss of superficial skin layers, dehydration, and secondary infections. The molecular basis of the clinical symptoms of SSSS is well understood. ETs are serine proteases with high substrate specificity, which selectively recognize and hydrolyze desmosomal proteins in the skin. The fascinating road leading to the discovery of ETs as the agents responsible for SSSS and the characterization of the molecular mechanism of their action, including recent advances in the field, are reviewed in this article.
Siegman-Igra, Y; Lavochkin, J; Schwartz, D; Konforti, N
A patient with meningitis and bacteremia due to Bacillus cereus is described. The patient had transsphenoidal hypophysectomy for chromophobe adenoma, complicated by rhinorrhea, which was corrected by subarachnoid drainage. Three weeks after removal of the drain, the patient presented with meningitis and died the following day. The causative organism was identified as B. cereus. The literature on Bacillus infections is reviewed with special attention to severe infections. A modified classification is proposed, dividing infections into superficial, closed-space and systemic ones. Sixty-one previously reported cases of systemic Bacillus infections are reviewed according to type of infection (endocarditis, meningitis or pulmonary infection), and the underlying conditions, ways of acquiring the infection, clinical picture and mortality are discussed.
Carretto, E; Barbarini, D; Poletti, F; Marzani, F C; Emmi, V; Marone, P
Bacillus cereus has sometimes been implicated in food poisoning and in opportunistic infections of seriously ill patients. This report describes an unusual case of persistent bacteremia and multiple organ failure associated with B. cereus in a patient admitted to our institution for lung cancer. The patient was undergoing treatment with an antimicrobial agent (imipenem) that was shown to be effective against the micro-organism in vitro. No portal of entry for the strain was detected. After treatment with vancomycin, also shown to be effective in vitro, no clinical improvement was noted and the patient died. Molecular studies showed that the same strain caused an episode of pseudobacteremia in another patient admitted to the same ICU room.
Janum, Sine H; Søvsø, Morten; Gradel, Kim O
and no recorded liver disease from the same region and time period. Methods. Retrospective review of medical records with registration of demography, co-morbidity, bacteriological, biochemical and clinical findings, and Child-Turcotte-Pugh scores. The primary outcome was 30-day mortality. Results. Mortality...... was significantly higher in patients with chronic liver disease (mortality rate ratio 2.2; 95% confidence interval 1.2-3.9) and it was correlated to Child-Turcotte-Pugh scores. CRP levels were not different between the three Child-Turcotte-Pugh classes (p = 0.33), and no linear correlation with 30-day mortality...... was observed. Conclusion. Mortality associated with bacteremia is increased in patients with chronic liver disease and it is correlated with Child-Turcotte-Pugh score. The prognostic information of initial CRP levels in patients with chronic liver disease is weak. The clinical management of patients...
Full Text Available Abstract Background Optimal antibiotic treatment strategies of Haemophilus infections are still needed. Therefore, 30-day case fatality rate (CFR of Haemophilus bacteremia and efficacy of various antibiotic treatment regimes were studied. Methods All episodes of Haemophilus bacteremia in the former Copenhagen County during the period 2000-9 were included in the study. Clinical and biochemical findings and outcome were collected retrospectively from medical records. Results 105 consecutive episodes were identified (median age: 69 years, with only 4 children H. influenzae, and 11% to other Haemophilus species. Pneumonia was the most common primary focus (in 48%, and 58% of the patients had Charlson comorbidity index > 1. Definitive antibiotic therapy was in 26 cases benzylpenicillin, in 12 cases aminopenicillins, in 50 cases cefuroxime and in 16 cases broadspectrum antibiotics, whereas 1 palliative case died without start of therapy. Whereas the use of broadspectrum antibiotics was related to the severity of the disease (admittance to ICU, need for assisted ventilation or hemodialysis, septic shock, no significant difference in clinical features was demonstrated for therapy with benzylpenicillin, aminopenicillin or cefuroxime, except benzylpenicillin was rarely administered to immunosuppressed patients. The CFR was 22% (23/105. The choice of empiric antibiotic therapy was not significantly associated with mortality (adequate vs. inadequate treatment: 23% (21/93 vs. 17% (2/12, respectively, P > 0.05. In contrast, definite antibiotic therapy with cefuroxime or aminopenicillins resulted in a significantly lower CFR than treatment with benzylpenicillin (12% (6/50 or 0% (0/12 vs. 39% (10/26, respectively, Log rank test P 0.02. When adjustments were made for other identified risk factors in bivariate logistic regression analysis, treatment with cefuroxime was still were found to be associated with a significantly lower CFR than for
Shigeta, Naoya; Ozaki, Kimiaki; Hori, Kensuke; Ito, Kimihiko; Nakayama, Masahiro; Nakahira, Kumiko; Yanagihara, Itaru
A 34-year-old parous woman developed high fever and threatened preterm labor after a 1-day trip, for which she was receiving prenatal care at a hospital. Three days after onset, at 24 4/7 weeks of gestation, she was transferred to our hospital in an emergency. Soon after the woman's arrival at our hospital, the infant was spontaneously stillborn via a transvaginal delivery. Laboratory tests revealed severe maternal disseminated intravascular coagulation with renal and liver insufficiency. Histopathologic examination of the placenta revealed vast fibrin deposition and remarkable neutrophilic infiltration in the intervillous space, suggesting a rare bacterial infection caused by Arthrobacter spp. The bacteria were predominantly detected in the placenta and maternal blood serum by common bacterial 16S rRNA sequencing after polymerase chain reaction amplification. We report the first case, to our knowledge, of bacteremia with Arthrobacter spp., which may lead to maternal disseminated intravascular coagulation and intrauterine fetal death.
Kishii, Kozue; Kikuchi, Ken; Tomida, Junko; Kawamura, Yoshiaki; Yoshida, Atsushi; Okuzumi, Katsuko; Moriya, Kyoji
Acinetobacter seifertii, a novel species of Acinetobacter, was first reported in 2015. A. seifertii strains were isolated from human clinical specimens (blood, respiratory tract, and ulcer) and hospital environments. Here, we report the first cases of bacteremia caused by A. seifertii in patients with catheter-related bloodstream infection in Japan. The patients favorably recovered, without any complications, after removal of the peripheral intravenous catheters and administration of antibiotics. The pathogens were initially identified as Acinetobacter baumannii, using phenotypic methods and the MicroScan Walkaway System; however, rpoB gene sequence analysis indicated 99.54% similarity to A. seifertii. Moreover, antimicrobial susceptibility testing revealed that one of the strains was not susceptible to gentamicin and ceftazidime. Our report shows that Acinetobacter species other than A. baumannii can also cause nosocomial infections and that accurate methods for the identification of causative agents should be developed.
Yakut, Nurhayat; Kepenekli, Eda Kadayifci; Karaaslan, Ayse; Atici, Serkan; Akkoc, Gulsen; Demir, Sevliya Ocal; Soysal, Ahmet; Bakir, Mustafa
Acinetobacter ursingii is an aerobic, gram-negative, opportunistic microorganism which is rarely isolated among Acinetobacter species. We present two immunocompetent infants who developed bacteremia due to A. ursingii. The first patient is a two -month- old boy who had been hospitalized in pediatric surgery unit for suspected tracheo-esophageal fistula because of recurrent aspiration pneumonia unresponsive to antibiotic therapy. The second patient is a fourteen -month- old boy with prolonged vomiting and diarrhea. A. ursingii was isolated from their blood cultures. They were successfully treated with ampicillin-sulbactam. Although A. ursingii has recently been isolated from a clinical specimen; reports of infection with A. ursingii in children are rare. A. ursingii should be kept in mind as an opportunistic microorganism in children.
Cuaron, Jesus A; Dulal, Santosh; Song, Yang; Singh, Atul K; Montelongo, Cesar E; Yu, Wanqin; Nagarajan, Vijayaraj; Jayaswal, Radheshyam K; Wilkinson, Brian J; Gustafson, John E
Tea tree oil (TTO) is a steam distillate of Melaleuca alternifolia that demonstrates broad-spectrum antibacterial activity. This study was designed to document how TTO challenge influences the Staphylococcus aureus transcriptome. Overall, bioinformatic analyses (S. aureus microarray meta-database) revealed that both ethanol and TTO induce related transcriptional alterations. TTO challenge led to the down-regulation of genes involved with energy-intensive transcription and translation, and altered the regulation of genes involved with heat shock (e.g. clpC, clpL, ctsR, dnaK, groES, groEL, grpE and hrcA) and cell wall metabolism (e.g. cwrA, isaA, sle1, vraSR and vraX). Inactivation of the heat shock gene dnaK or vraSR which encodes a two-component regulatory system that responds to peptidoglycan biosynthesis inhibition led to an increase in TTO susceptibility which demonstrates a protective role for these genes in the S. aureus TTO response. A gene (mmpL) encoding a putative resistance, nodulation and cell division efflux pump was also highly induced by TTO. The principal antimicrobial TTO terpene, terpinen-4-ol, altered ten genes in a transcriptional direction analogous to TTO. Collectively, this study provides additional insight into the response of a bacterial pathogen to the antimicrobial terpene mixture TTO.
Biehle, Lauren R.; Cottreau, Jessica M.; Thompson, David J.; Filipek, Rachel L.; O’Donnell, J. Nicholas; Lasco, Todd M.; Mahoney, Monica V.; Hirsch, Elizabeth B.
Background Extensive dissemination of carbapenemase-producing Enterobacteriaceae has led to increased resistance among Klebsiella species. Carbapenems are used as a last resort against resistant pathogens, but carbapenemase production can lead to therapy failure. Identification of risk factors for mortality and assessment of current susceptibility breakpoints are valuable for improving patient outcomes. Aim The objective of this study was to evaluate outcomes and risk factors for mortality among patients treated with carbapenems for Klebsiella spp. bacteremia. Methods Patients hospitalized between 2006 and 2012 with blood cultures positive for Klebsiella spp. who received ≥ 48 hours of carbapenem treatment within 72 hours of positive culture were included in this retrospective study. Patient data were retrieved from electronic medical records. Multivariate logistic regression was used to identify risk factors for 30-day hospital mortality. Results One hundred seven patients were included. The mean patient age was 61.5 years and the median APACHE II score was 13 ± 6.2. Overall, 30-day hospital mortality was 9.3%. After adjusting for confounding variables, 30-day mortality was associated with baseline APACHE II score (OR, 1.17; 95% CI, 1.01–1.35; P = 0.03), length of stay prior to index culture (OR, 1.03; 95% CI, 1.00–1.06; P = 0.04), and carbapenem non-susceptible (imipenem or meropenem MIC > 1 mg/L) infection (OR, 9.08; 95% CI, 1.17–70.51; P = 0.04). Conclusions Baseline severity of illness and length of stay prior to culture were associated with 30-day mortality and should be considered when treating patients with Klebsiella bacteremia. These data support the change in carbapenem breakpoints for Klebsiella species. PMID:26618357
Full Text Available BACKGROUND: Periodontal infections are independent risk factors for atherosclerosis. However, the exact mechanisms underlying this link are yet unclear. Here, we evaluate the in vivo effects of bacteremia with a periodontal pathogen on endothelial progenitors, bone marrow-derived cells capable of endothelial regeneration, and delineate the critical pathways for these effects. METHODS: 12-week old C57bl6 wildtype or toll-like receptor (TLR-2 deficient mice were repeatedly intravenously challenged with 10⁹ live P. gingivalis 381 or vehicle. Numbers of Sca1+/flk1+ progenitors, circulating angiogenic cells, CFU-Hill, and late-outgrowth EPC were measured by FACS/culture. Endothelial function was assessed using isolated organ baths, reendothelization was measured in a carotid injury model. RANKL/osteoprotegerin levels were assessed by ELISA/qPCR. RESULTS: In wildtype mice challenged with intravenous P.gingivalis, numbers of Sca1+/flk1+ progenitors, CAC, CFU-Hill, and late-outgrowth EPC were strongly increased in peripheral circulation and spleen, whereas Sca1+/flk1+ progenitor numbers in bone marrow decreased. Circulating EPCs were functional, as indicated by improved endothelial function and improved reendothelization in infected mice. The osteoprotegerin/RANKL ratio was increased after P. gingivalis challenge in the bone marrow niche of wildtype mice and late-outgrowth EPC in vitro. Conversely, in mice deficient in TLR2, no increase in progenitor mobilization or osteoprotegerin/RANKL ratio was detected. CONCLUSION: Recurrent transient bacteremias, a feature of periodontitis, increase peripheral EPC counts and decrease EPC pools in the bone marrow, thereby possibly reducing overall endothelial regeneration capacity, conceivably explaining pro-atherogenic properties of periodontal infections. These effects are seemingly mediated by toll-like receptor (TLR-2.
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Staphylococcus aureus serological reagents. 866... Staphylococcus aureus serological reagents. (a) Identification. Staphylococcus aureus serological reagents are... epidemiological information on these diseases. Certain strains of Staphylococcus aureus produce an...
Atwood, Danielle N; Beenken, Karen E; Loughran, Allister J; Meeker, Daniel G; Lantz, Tamara L; Graham, Justin W; Spencer, Horace J; Smeltzer, Mark S
We demonstrate that mutation of xerC, which reportedly encodes a homologue of an Escherichia coli recombinase, limits biofilm formation in the methicillin-resistant Staphylococcus aureus strain LAC and the methicillin-sensitive strain UAMS-1. This was not due to the decreased production of the polysaccharide intracellular adhesin (PIA) in either strain because the amount of PIA was increased in a UAMS-1xerC mutant and undetectable in both LAC and its isogenic xerC mutant. Mutation of xerC also resulted in the increased production of extracellular proteases and nucleases in both LAC and UAMS-1, and limiting the production of either class of enzymes increased biofilm formation in the isogenic xerC mutants. More importantly, the limited capacity to form a biofilm was correlated with increased antibiotic susceptibility in both strains in the context of an established biofilm in vivo. Mutation of xerC also attenuated virulence in a murine bacteremia model, as assessed on the basis of the bacterial loads in internal organs and overall lethality. It also resulted in the decreased accumulation of alpha toxin and the increased accumulation of protein A. These findings suggest that xerC may impact the functional status of agr. This was confirmed by demonstrating the reduced accumulation of RNAIII and AgrA in LAC and UAMS-1xerC mutants. However, this cannot account for the biofilm-deficient phenotype of xerC mutants because mutation of agr did not limit biofilm formation in either strain. These results demonstrate that xerC contributes to biofilm-associated infections and acute bacteremia and that this is likely due to agr-independent and -dependent pathways, respectively.
Hanberger, H.; Walther, S.; Leone, M.; Barie, P.S.; Rello, J.; Lipman, J.; Marshall, J.C.; Anzueto, A.; Sakr, Y.; Pickkers, P.; Felleiter, P.; Engoren, M.; Vincent, J.L.
Controversy continues regarding whether the presence of meticillin resistance increases mortality risk in Staphylococcus aureus infections. In this study, we assessed the role of meticillin resistance in survival of patients with S. aureus infection included in the EPIC II point-prevalence study of
Costa, Sofia Santos; Viveiros, Miguel; Amaral, Leonard; Couto, Isabel
The emergence of infections caused by multi- or pan-resistant bacteria in the hospital or in the community settings is an increasing health concern. Albeit there is no single resistance mechanism behind multiresistance, multidrug efflux pumps, proteins that cells use to detoxify from noxious compounds, seem to play a key role in the emergence of these multidrug resistant (MDR) bacteria. During the last decades, experimental data has established their contribution to low level resistance to antimicrobials in bacteria and their potential role in the appearance of MDR phenotypes, by the extrusion of multiple, unrelated compounds. Recent studies suggest that efflux pumps may be used by the cell as a first-line defense mechanism, avoiding the drug to reach lethal concentrations, until a stable, more efficient alteration occurs, that allows survival in the presence of that agent. In this paper we review the current knowledge on MDR efflux pumps and their intricate regulatory network in Staphylococcus aureus, a major pathogen, responsible from mild to life-threatening infections. Particular emphasis will be given to the potential role that S. aureus MDR efflux pumps, either chromosomal or plasmid-encoded, have on resistance towards different antimicrobial agents and on the selection of drug - resistant strains. We will also discuss the many questions that still remain on the role of each specific efflux pump and the need to establish appropriate methodological approaches to address all these questions.
Caballero-Granado, F J; Cisneros, J M; Luque, R; Torres-Tortosa, M; Gamboa, F; Díez, F; Villanueva, J L; Pérez-Cano, R; Pasquau, J; Merino, D; Menchero, A; Mora, D; López-Ruz, M A; Vergara, A
A prospective, multicenter study was carried out over a period of 10 months. All patients with clinically significant bacteremia caused by Enterococcus spp. were included. The epidemiological, microbiological, clinical, and prognostic features and the relationship of these features to the presence of high-level resistance to gentamicin (HLRG) were studied. Ninety-three patients with enterococcal bacteremia were included, and 31 of these cases were caused by HLRG (33%). The multivariate analysis selected chronic renal failure, intensive care unit stay, previous use of antimicrobial agents, and Enterococcus faecalis species as the independent risk factors that influenced the development of HLRG. The strains with HLRG showed lower levels of susceptibility to penicillin and ciprofloxacin. Clinical features (except for chronic renal failure) were similar in both groups of patients. HLRG did not influence the prognosis for patients with enterococcal bacteremia in terms of either the crude mortality rate (29% for patients with bacteremia caused by enterococci with HLRG and 28% for patients not infected with strains with HLRG) or the hospital stay after the acquisition of enterococcal bacteremia. Hemodynamic compromise, inappropriate antimicrobial therapy, and mechanical ventilation were revealed in the multivariate analysis to be the independent risk factors for mortality. Prolonged hospitalization was associated with the nosocomial acquisition of bacteremia and polymicrobial infections.
Full Text Available Os estafilococos coagulase-negativos (ECN são importantes agentes etiológicos das bacteremias hospitalares e freqüentemente considerados como contaminantes de hemoculturas. No período de outubro de 1990 a setembro de 1992, foram estudadas 300 hemoculturas positivas para ECN no Hospital São Paulo, sendo 141 bacteremias consideradas de origem hospitalar. Com o objetivo de diferenciar as bacteremias hospitalares verdadeiras das contaminantes por ECN, foram definidos critérios clínicos e microbiológicos. Apenas 20,6% das bacteremias hospitalares por ECN foram consideradas como verdadeiras. A maior freqüência de recém-nascidos internados na unidade de terapia intensiva neonatal, a presença de cateter intravascular e a utilização de nutrição parenteral foram achados significativos. Não houve diferença significante quanto a resistência a oxacilina e produção de SLIME entre os ECN isolados das bacteremias verdadeiras e contaminantes. O critério clínico e a positividade da hemocultura até 48 horas após a incubação, utilizados em nossa definição, foram úteis para caracterizar as bacteremias verdadeiras por ECN.
Traverso Sandra Davi; Cunha Leonardo da; Fernandes Joaquim César Teixeira; Loretti Alexandre Paulino; Rhoden Adriana; Wunder Jr. Elsio; Driemeier David
Em uma criação composta por 1800 coelhos, 33% das matrizes apresentaram mastite e lesões cutâneas crostosas e purulentas. Estes animais apresentavam-se entre 10 a- 12 meses de idade e em segunda parição. Quinze coelhos afetados foram sacrificados e necropsiados. Na necropsia, além das lesões cutâneas haviam microabscessos em diversos órgãos. Das amostras coletadas isolou-se Staphylococcus aureus subesp. aureus. S. aureus subesp. aureus também foi isolado de "swab" nasal coletado do tratador e...
Full Text Available The detection of the activities of pathogen-encoded virulence factors by the innate immune system has emerged as a new paradigm of pathogen recognition. Much remains to be determined with regard to the molecular and cellular components contributing to this defense mechanism in mammals and importance during infection. Here, we reveal the central role of the IL-1β signaling axis and Gr1+ cells in controlling the Escherichia coli burden in the blood in response to the sensing of the Rho GTPase-activating toxin CNF1. Consistently, this innate immune response is abrogated in caspase-1/11-impaired mice or following the treatment of infected mice with an IL-1β antagonist. In vitro experiments further revealed the synergistic effects of CNF1 and LPS in promoting the maturation/secretion of IL-1β and establishing the roles of Rac, ASC and caspase-1 in this pathway. Furthermore, we found that the α-hemolysin toxin inhibits IL-1β secretion without affecting the recruitment of Gr1+ cells. Here, we report the first example of anti-virulence-triggered immunity counteracted by a pore-forming toxin during bacteremia.
Epidemiology of extended spectrum β-lactamase producing Enterobacter bacteremia in a brazilian hospital Epidemiologia de bacteremia causadas por Enterobacter produtores de β-lactamases de espectro estendido em um hospital brasileiro
INTRODUCTION: Enterobacter can be included in the group of extended spectrum β-lactamases (EBSL)-producing bacteria, though few studies exist evaluating risk factors associated with this microorganism. A retrospective cohort study was conducted to determine risk factors associated with ESBL-producing-Enterobacter and mortality METHODS: A retrospective cohort study with 58 bacteremia caused by ESBL-producing-Enterobacter (28 cases) and non-ESBL (30 cases) RESULTS: Risk factors associated ...
The ribosome is a large cellular machinery that performs the protein synthesis in every living cell. Therefore, the ribosome is one of the major targets of naturally produced antibiotics, which can kill bacterial cells by blocking protein synthesis. However, some bacteria are resistant to these antibiotics due to small modifications of their ribosomes. Among them, Staphylococcus aureus (S. aureus) is a severe pathogen that causes numerous infections in humans. The crystal structures of comple...
Olson, Michael E; Nygaard, Tyler K; Ackermann, Laynez; Watkins, Robert L; Zurek, Oliwia W; Pallister, Kyler B; Griffith, Shannon; Kiedrowski, Megan R; Flack, Caralyn E; Kavanaugh, Jeffrey S; Kreiswirth, Barry N; Horswill, Alexander R; Voyich, Jovanka M
Several prominent bacterial pathogens secrete nuclease (Nuc) enzymes that have an important role in combating the host immune response. Early studies of Staphylococcus aureus Nuc attributed its regulation to the agr quorum-sensing system. However, recent microarray data have indicated that nuc is under the control of the SaeRS two-component system, which is a major regulator of S. aureus virulence determinants. Here we report that the nuc gene is directly controlled by the SaeRS two-component system through reporter fusion, immunoblotting, Nuc activity measurements, promoter mapping, and binding studies, and additionally, we were unable identify a notable regulatory link to the agr system. The observed SaeRS-dependent regulation was conserved across a wide spectrum of representative S. aureus isolates. Moreover, with community-associated methicillin-resistant S. aureus (CA MRSA) in a mouse model of peritonitis, we observed in vivo expression of Nuc activity in an SaeRS-dependent manner and determined that Nuc is a virulence factor that is important for in vivo survival, confirming the enzyme's role as a contributor to invasive disease. Finally, natural polymorphisms were identified in the SaeRS proteins, one of which was linked to Nuc regulation in a CA MRSA USA300 endocarditis isolate. Altogether, our findings demonstrate that Nuc is an important S. aureus virulence factor and part of the SaeRS regulon.
Olson, Michael E.; Nygaard, Tyler K.; Ackermann, Laynez; Watkins, Robert L.; Zurek, Oliwia W.; Pallister, Kyler B.; Griffith, Shannon; Kiedrowski, Megan R.; Flack, Caralyn E.; Kavanaugh, Jeffrey S.; Kreiswirth, Barry N.
Several prominent bacterial pathogens secrete nuclease (Nuc) enzymes that have an important role in combating the host immune response. Early studies of Staphylococcus aureus Nuc attributed its regulation to the agr quorum-sensing system. However, recent microarray data have indicated that nuc is under the control of the SaeRS two-component system, which is a major regulator of S. aureus virulence determinants. Here we report that the nuc gene is directly controlled by the SaeRS two-component system through reporter fusion, immunoblotting, Nuc activity measurements, promoter mapping, and binding studies, and additionally, we were unable identify a notable regulatory link to the agr system. The observed SaeRS-dependent regulation was conserved across a wide spectrum of representative S. aureus isolates. Moreover, with community-associated methicillin-resistant S. aureus (CA MRSA) in a mouse model of peritonitis, we observed in vivo expression of Nuc activity in an SaeRS-dependent manner and determined that Nuc is a virulence factor that is important for in vivo survival, confirming the enzyme's role as a contributor to invasive disease. Finally, natural polymorphisms were identified in the SaeRS proteins, one of which was linked to Nuc regulation in a CA MRSA USA300 endocarditis isolate. Altogether, our findings demonstrate that Nuc is an important S. aureus virulence factor and part of the SaeRS regulon. PMID:23381999
Jingjing, Zhang; Nan, Zhang; Wei, Wu; Qinghe, Guo; Weijuan, Wang; Peng, Wang; Xiangpeng, Wang
Macrophages play a crucial role in host innate anti-Staphylococcus aureus defense, which is tightly regulated by multiple factors, including microRNAs. A recent study showed that miR-24 plays an important role in macrophage polarization. Here, we investigated the biological function of miR-24 in S. aureus-stimulated macrophages. The results revealed that miR-24 expression was significantly decreased in both human and mouse macrophage cell lines with S. aureus stimulation in a time-dependent manner. Moreover, miR-24 overexpression significantly decreased the production of M1 phenotype markers, such as IL-6, iNOS, TNF-α, CD86, and CD80, whereas it increased the production of M2 markers, such as Arg1, CCL17, CCL22, CD163, and CD206, in S. aureus-stimulated macrophages. Conversely, knockdown of miR-24 promoted M1 macrophage polarization but diminished M2 macrophage polarization in S. aureus-stimulated macrophages. Furthermore, CHI3L1 was predicted as a target gene of miR-24 using bioinformatics software and identified by luciferase reporter assay. Additionally, miR-24 overexpression inhibited CHI3L1 expression and downregulated the downstream MAPK pathway in S. aureus-stimulated macrophages. Finally, CHI3L1 overexpression rescued macrophage polarization and MAPK pathway inhibition induced by miR-24 mimic transfection in S. aureus-stimulated macrophages. In conclusion, the data suggest that miR-24 serves as a molecular regulator in S. aureus-induced macrophage polarization through targeting of CHI3L1 and regulation of the MAPK pathway, which may provide a promising therapeutic target for S. aureus-related infections and inflammatory diseases.
Nielsen, Stig Lønberg; Pedersen, Court; Ostergaard, Christian;
Objective. We examined whether specific time windows after hospital admission reflected a sharp transition between community and hospital acquisition of bacteremia. We further examined whether different time windows to distinguish between community acquisition, healthcare association (HCA...... mortality pertaining to bacteremia 0, 1, 2, …, 30, and 31 days and later after admission. Next, we assessed whether different admission (0-1, 0-2, 0-3, 0-7 days) and HCA (30, 90 days) time windows were associated with changes in odds ratio (OR) and area under the receiver operating characteristic (ROC......) curve for 30-day mortality, adjusting for sex, age, comorbidity, and microorganisms. Results. For 56,606 bacteremic episodes, no sharp transitions were detected on a specific day after admission. Among the 8 combined time windows, ORs for 30-day mortality varied from 1.30 (95% confidence interval [CI...
de Kraker, Marlieke E. A.; Davey, Peter G.; Grundmann, Hajo
Background: The relative importance of human diseases is conventionally assessed by cause-specific mortality, morbidity, and economic impact. Current estimates for infections caused by antibiotic-resistant bacteria are not sufficiently supported by quantitative empirical data. This study determined
Caiaffa-Filho, Helio Hehl; Trindade, Priscila A; Gabriela da Cunha, Paula; Alencar, Cecilia Salete; Prado, Gladys V B; Rossi, Flavia; Levin, Anna S
Fifty consecutive MRSA blood isolates were evaluated: 30(60%) carried SCCmec type II (single PFGE clone; sequence type 5 or ST105); 12 (26%), IV; 5 (10%), III; 3 (6%), I. Brazilian endemic clone, carrying SCCmec type III, has been the main nosocomial clone in Brazil; however, this study showed that a clone carrying type II predominated.
Brady, Adam C; Lewis, James S; Pfeiffer, Christopher D
Rapid molecular techniques to identify resistant pathogens are revolutionizing antibiotic stewardship; however, it is important to recognize the limitations of these techniques. Herein we describe two cases of bacteremia that were both initially identified by genotypic testing as carbapenem-resistant Acinetobacter spp. and subsequently identified phenotypically as carbapenem-susceptible A. radioresistens. The genotypic results prompted unnecessary broad-spectrum antibiotic use and infection control concerns.
Hammond, Ray K.; White, David C.
The carotenoid pigments of Staphylococcus aureus U-71 were identified as phytoene; ζ-carotene; δ-carotene; phytofluenol; a phytofluenol-like carotenoid, rubixanthin; and three rubixanthin-like carotenoids after extraction, saponification, chromatographic separation, and determination of their absorption spectra. There was no evidence of carotenoid esters or glycoside ethers in the extract before saponification. During the aerobic growth cycle the total carotenoids increased from 45 to 1,000 nmoles per g (dry weight), with the greatest increases in the polar, hydroxylated carotenoids. During the anaerobic growth cycle, the total carotenoids increased from 20 nmoles per g (dry weight) to 80 nmoles per g (dry weight), and only traces of the polar carotenoids were formed. Light had no effect on carotenoid synthesis. About 0.14% of the mevalonate-2-14C added to the culture was incorporated into the carotenoids during each bacterial doubling. The total carotenoids did not lose radioactivity when grown in the absence of 14C for 2.5 bacterial doublings. The total carotenoids did not lose radioactivity when grown in the absence of 14C for 2.5 bacterial doublings. The incorporation and turnover of 14C indicated the carotenes were sequentially desaturated and hydroxylated to form the polar carotenoids. PMID:5423369
Full Text Available Campylobacter es un importante agente causante de enfermedad en el ser humano en nuestro medio. Los casos de bacteriemia ocurren principalmente en pacientes inmunosuprimidos y son debidos frecuentemente a C. fetus. Sin embargo la bacteriemia es un episodio que también se ha observado en pacientes con enteritis por C. jejuni. Referimos dos pacientes con enteritis grave y bacteriemia, ambos con enfermedades concomitantes compatibles con inmunodepresión: uno con síndrome nefrótico de larga data y otro con hepatopatía crónica con cirrosis. Destacamos que los dos casos presentaron hematemesis y uno de ellos, enterorragia. Sugerimos prestar atención a la coloración de Gram durante el subcultivo de los caldos con hemocultivos, en busca de formas características de esta especie, y en ese caso emplear medios de cultivo en microaerofilia a 37 y 42 °C.Campylobacter is an important agent of illness in human beings. Bacteremia occurs principally in the immunocompromissed host and is frequently due to C. fetus. Nevertheless bacteremia also has been observed in patients with enteritis due to C. jejuni. We refer two cases of patients with severe enteritis and bacteremia, both of them with immunosupressive concomitant diseases such as nephrotic syndrome and chronic cirrotic hepatopathy. Both patients presented hemathemesis.
Castroagudín, J F; Lorenzo Solar, M; Martínez Rey, C; Brage Varela, A; Torre, J A; González Quintela, A
The association of Streptococcus bovis bacteremia and endocarditis with colonic pathology, mainly neoplastic, is well known. Its relationship with liver disease without evidence of gastrointestinal disease has been rarely described. To analyze the association between S. bovis infection and liver disease, positive blood cultures for this microorganism in hospitalized patients in the Internal Medicine and Gastroenterology Departments from December 1993 until October 1995, have been reviewed. Three cases of S. bovis infection (one bacteremia, two endocarditis) were found. Alcoholic liver disease was diagnosed in all three patients, with associated hepatitis C virus in one of them. Colonic pathology was excluded by colonoscopy and/or barium enema. Other gastrointestinal disorders were excluded by means of gastroscopy, barium gastrointestinal study and abdominal ultrasonography. Antibiotic therapy was based in betalactamics, with associated aminoglycoside in two cases. One patient needed aortic and mitral valve replacement and another one needed orthotopic liver transplantation. No new gastrointestinal pathology emerged in the follow-up (5-23 months). Cases of S. bovis bacteremia and endocarditis should be screened not also for colonic pathology, but also for liver disease, particularly in alcoholics.
Ratzinger, Franz; Dedeyan, Michel; Rammerstorfer, Matthias; Perkmann, Thomas; Burgmann, Heinz; Makristathis, Athanasios; Dorffner, Georg; Loetsch, Felix; Blacky, Alexander; Ramharter, Michael
Adequate early empiric antibiotic therapy is pivotal for the outcome of patients with bloodstream infections. In clinical practice the use of surrogate laboratory parameters is frequently proposed to predict underlying bacterial pathogens; however there is no clear evidence for this assumption. In this study, we investigated the discriminatory capacity of predictive models consisting of routinely available laboratory parameters to predict the presence of Gram-positive or Gram-negative bacteremia. Major machine learning algorithms were screened for their capacity to maximize the area under the receiver operating characteristic curve (ROC-AUC) for discriminating between Gram-positive and Gram-negative cases. Data from 23,765 patients with clinically suspected bacteremia were screened and 1,180 bacteremic patients were included in the study. A relative predominance of Gram-negative bacteremia (54.0%), which was more pronounced in females (59.1%), was observed. The final model achieved 0.675 ROC-AUC resulting in 44.57% sensitivity and 79.75% specificity. Various parameters presented a significant difference between both genders. In gender-specific models, the discriminatory potency was slightly improved. The results of this study do not support the use of surrogate laboratory parameters for predicting classes of causative pathogens. In this patient cohort, gender-specific differences in various laboratory parameters were observed, indicating differences in the host response between genders.
Markley, John Daniel; Edmond, Michael B; Major, Yvette; Bearman, Gonzalo; Stevens, Michael P
We sought to identify staphylococcal contamination of gymnasium surfaces. Various environmental surfaces were cultured at a university fitness center. Ten out of 99 samples yielded Staphylococcus aureus, all of which were methicillin-susceptible. Gym surfaces may be colonized with staphylococci and could play a role in community transmission of staphylococcal species.
Moran, Josephine C.; Alorabi, Jamal A.; Horsburgh, Malcolm J.
Staphylococcal colonization of human skin is ubiquitous, with particular species more frequent at different body sites. Whereas Staphylococcus epidermidis can be isolated from the skin of every individual tested, Staphylococcus aureus is isolated from arginine deiminase, the oxygen-responsive NreABC nitrogen regulation system and the nitrate and nitrite reduction pathways. The role of S. aureus ACME and chromosomal arginine deiminase pathways in sapienic acid resistance was determined through mutational studies. We speculate that ammonia production could contribute to sapienic acid resistance in staphylococci. PMID:28179897
BO Shi-ning; BO Jian; NING Yong-zhong; ZHAO Yu; LU Xiao-lin; YANG Ji-yong; ZHU Xi; YAO Gai-qi
Background Previous studies indicated that the time to positivity (TTP) of blood culture is a parameter correlating with degree of the bacteremia and outcome in patients with bloodstream infections caused by Escherichia coli (E.co/i). The objective of this study was to further investigate the diagnostic and prognostic power of using TTP to predict E. coli bacteremia.Methods A retrospective cohort study at two university hospitals was conducted. We retrieved all the medical records of those with E. coli bloodstream infection according to the records generated by their microbiology departments.Univariate and multivariate analyses were applied to identify clinical factors correlating with fast bacterial growth and significant prognostic factors for hospital mortality.Results Medical records of 353 episodes of E. coli bacteremia diagnosed between January 1,2007 and December 31,2009 were retrieved in the investigation. Univariate analysis demonstrated that the TTP≤7 hours group is associated with higher incidence of active malignancies (41.7% vs. 27.2%, P=0.010), neutropenia (30% vs.14.3%, P=0.007), primary bacteremia (55.0% vs. 33.4%, P=0.002), and poorer outcome (hospital mortality 43.3% vs.11.9%, P=0.000) than the TTP ＞7 hours group. Multivariate analysis revealed that the significant predictors of hospital mortality, in rank order from high to low, were TTP (for TTP ＜7 hours, odds ratio (OR): 4.886; 95% confidence interval (CI): 2.572-9.283; P=0.000),neutropenia (OR: 2.800; 95% CI:1.428-5.490; P=0.003), comedication of steroids or immunosuppressive agents (OR:2.670; 95% CI: 0.971-7.342; P=0.057).Conclusions Incidence of malignancies, neutropenia and primary bacterernia correlates with fast bacterial growth in patients with E. coli bacteremia. The parameter of TTP has been identified as a variable of highest correlation to hospital mortality and therefore can be potentially utilized as a mortality prognostic marker.
Lam, O L T; McGrath, C; Bandara, H M H N; Li, L S W; Samaranayake, L P
The oral cavity serves as a reservoir of Staphylococcus aureus for infection of the lower respiratory tract and cross-infection to other patients. This systematic review was designed to examine the effectiveness of oral health promotion interventions on this pathogen. The PubMed, ISI Web of Science, and Cochrane Library databases were searched for clinical trials assessing the effect of oral health promotion interventions on oral and oropharyngeal carriage of S. aureus. Oral health promotion interventions on oral reservoirs of S. aureus in both systemically healthy and medically compromised groups consisted of oral hygiene interventions only. There was a lack of evidence pertaining to the effectiveness of mechanical oral hygiene interventions against this pathogen. Chlorhexidine delivered in oral hygiene products such as mouthrinses, gels, and sprays appeared to have some utility against S. aureus, although some studies found equivocal effects. There was a dearth of studies investigating the efficacy of other chemical agents. Although many chemical agents contained in oral hygiene products have proven in vitro activity against S. aureus, their clinical effectiveness and potential role as adjuncts or alternative therapies to conventional treatment remain to be confirmed by further high-quality randomized controlled trials.
Kwiecinski, Jakub; Peetermans, Marijke; Liesenborghs, Laurens; Na, Manli; Björnsdottir, Halla; Zhu, Xuefeng; Jacobsson, Gunnar; Johansson, Bengt R; Geoghegan, Joan A; Foster, Timothy J; Josefsson, Elisabet; Bylund, Johan; Verhamme, Peter; Jin, Tao
Staphylococcus aureus biofilms, a leading cause of persistent infections, are highly resistant to immune defenses and antimicrobial therapies. In the present study, we investigated the contribution of fibrin and staphylokinase (Sak) to biofilm formation. In both clinical S. aureus isolates and laboratory strains, high Sak-producing strains formed less biofilm than strains that lacked Sak, suggesting that Sak prevents biofilm formation. In addition, Sak induced detachment of mature biofilms. This effect depended on plasminogen activation by Sak. Host-derived fibrin, the main substrate cleaved by Sak-activated plasminogen, was a major component of biofilm matrix, and dissolution of this fibrin scaffold greatly increased susceptibility of biofilms to antibiotics and neutrophil phagocytosis. Sak also attenuated biofilm-associated catheter infections in mouse models. In conclusion, our results reveal a novel role for Sak-induced plasminogen activation that prevents S. aureus biofilm formation and induces detachment of existing biofilms through proteolytic cleavage of biofilm matrix components.
Maria Antonietta Distasi
Full Text Available Background. Anaerobic bacteria are part of the commensal bacterial flora of skin and mucosae. Iatrogenic and pathological conditions altering this commensal relationship cause life-threatening diseases. Materials and Methods. We analysed the blood cultures sent to the microbiology of our hospital between 2008 and the first quarter of 2013 to measure the frequency of bacteraemia caused by anaerobia. We examined 3138 vials of blood cultures for anaerobia, inoculated following in-house standard procedures. The colonies grown in absence of air were subjected to biochemical analysis. The MICs of metronidazole for 23 of the 26 organisms was tested. Results. Twelve bacteria of the Bacteroides genus were identified, 9 Propionibacterium acnes, 1 Peptosctreptococcus micros, 1 Lactobacillus acidophilus, 1 Clostridium perfringens, 1 Prevotella oralis, 1 Eubacterium lentum. Conclusions. The analysis of the results suggests that the incidence of cultures positive to anaerobia was constant across the years. We note that advanced age, altered mucocutaneous tropism, alterations to the oral and intestinal bacterial flora intensify the risk of anaerobial pathogenicity. The analysis of the metronidazole-determined MIC suggests that the intestinal anaerobic flora responds well to therapy and prophylaxis with Metronidazole, while the anaerobic bacteria residing on skin and other mucosae are resistant. It is however hard to determine the clinical impact of anaerobic bacteremiae and their effect on the outcome of the patient, due to the scarcity of available clinical data.
Endo, Shiro; Yano, Hisakazu; Kanamori, Hajime; Inomata, Shinya; Aoyagi, Tetsuji; Hatta, Masumitsu; Gu, Yoshiaki; Tokuda, Koichi; Kitagawa, Miho; Kaku, Mitsuo
Acinetobacter baumannii is generally the most frequently isolated Acinetobacter species. Sequence analysis techniques allow reliable identification of Acinetobacter isolates at the species level. Forty-eight clinical isolates of Acinetobacter spp. were obtained from blood cultures at Tohoku University Hospital. These isolates were identified at the species level by partial sequencing of the RNA polymerase β-subunit (rpoB), 16S rRNA, and gyrB genes. Then further characterization was done by using the PCR for detection of OXA-type β-lactamase gene clusters, metallo-β-lactamases, and carO genes. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing were also performed. The most frequent isolate was Acinetobacter soli (27.1%). Six of the 13 A. soli isolates were carbapenem nonsusceptible, and all of these isolates produced IMP-1. PFGE revealed that the 13 A. soli isolates were divided into 8 clusters. This study demonstrated that A. soli accounted for a high proportion of Acinetobacter isolates causing bacteremia at a Japanese tertiary hospital. Non-A. baumannii species were identified more frequently than A. baumannii and carbapenem-nonsusceptible isolates were found among the non-A. baumannii strains. These results emphasize the importance of performing epidemiological investigations of Acinetobacter species.
Kulohoma, Benard W; Cornick, Jennifer E; Chaguza, Chrispin; Yalcin, Feyruz; Harris, Simon R; Gray, Katherine J; Kiran, Anmol M; Molyneux, Elizabeth; French, Neil; Parkhill, Julian; Faragher, Brian E; Everett, Dean B; Bentley, Stephen D; Heyderman, Robert S
Streptococcus pneumoniae is a nasopharyngeal commensal that occasionally invades normally sterile sites to cause bloodstream infection and meningitis. Although the pneumococcal population structure and evolutionary genetics are well defined, it is not clear whether pneumococci that cause meningitis are genetically distinct from those that do not. Here, we used whole-genome sequencing of 140 isolates of S. pneumoniae recovered from bloodstream infection (n = 70) and meningitis (n = 70) to compare their genetic contents. By fitting a double-exponential decaying-function model, we show that these isolates share a core of 1,427 genes (95% confidence interval [CI], 1,425 to 1,435 genes) and that there is no difference in the core genome or accessory gene content from these disease manifestations. Gene presence/absence alone therefore does not explain the virulence behavior of pneumococci that reach the meninges. Our analysis, however, supports the requirement of a range of previously described virulence factors and vaccine candidates for both meningitis- and bacteremia-causing pneumococci. This high-resolution view suggests that, despite considerable competency for genetic exchange, all pneumococci are under considerable pressure to retain key components advantageous for colonization and transmission and that these components are essential for access to and survival in sterile sites.
Wildi, K; Tschudin-Sutter, S; Dell-Kuster, S; Frei, R; Bucher, H C; Nüesch, R
Blood cultures are routinely taken in outpatients with fever and suspected bacterial infections. However, in the majority of cases, they are not informative and of limited value for clinical decision making. The aim of this study was therefore to investigate factors associated with positive blood cultures in outpatients presenting to an outpatient clinic and emergency room. This was a case-control study of all outpatients with positive blood cultures from January 1, 2006 to October 31, 2007 and matched control patients with negative blood cultures in the same time period. Microbiology results and medical charts were reviewed to determine factors associated with positive blood cultures. The presence of a systemic inflammation response syndrome (SIRS) (OR 2.7, 95% Cl 1.0-7.2) and increased C-reactive protein (CRP) (OR 1.1 per 10 mg/l, 95% Cl 1.0-1.2) were the most powerful predictive values for the development of positive blood cultures. In positive cases serum albumin was lower (35 mg/l versus 39 mg/l) than in controls. SIRS, increasing CRP and low albumin were associated with positive blood cultures in outpatients. With simple clinical assessment and few laboratory tests indicative of infection, it is possible to define a group at higher risk for bacteremia in outpatients.
Full Text Available Abstract Background Staphylococcus aureus is an important pathogen that causes biofilm-associated infection in humans. Autoinducer 2 (AI-2, a quorum-sensing (QS signal for interspecies communication, has a wide range of regulatory functions in both Gram-positive and Gram-negative bacteria, but its exact role in biofilm formation in S. aureus remains unclear. Results Here we demonstrate that mutation of the AI-2 synthase gene luxS in S. aureus RN6390B results in increased biofilm formation compared with the wild-type (WT strain under static, flowing and anaerobic conditions and in a mouse model. Addition of the chemically synthesized AI-2 precursor in the luxS mutation strain (ΔluxS restored the WT phenotype. Real-time RT-PCR analysis showed that AI-2 activated the transcription of icaR, a repressor of the ica operon, and subsequently a decreased level of icaA transcription, which was presumably the main reason why luxS mutation influences biofilm formation. Furthermore, we compared the roles of the agr-mediated QS system and the LuxS/AI-2 QS system in the regulation of biofilm formation using the ΔluxS strain, RN6911 and the Δagr ΔluxS strain. Our data indicate a cumulative effect of the two QS systems on the regulation of biofilm formation in S. aureus. Conclusion These findings demonstrate that AI-2 can decrease biofilm formation in S. aureus via an icaR-activation pathway. This study may provide clues for therapy in S. aureus biofilm-associated infection.
Fitzgerald, J Ross; Holden, Matthew T G
Staphylococcus aureus is a major human pathogen and an important cause of livestock infections. The first S. aureus genomes to be published, 15 years ago, provided the first view of genome structure and gene content. Since then, thousands of genomes from a wide array of strains from different sources have been sequenced. Comparison of these sequences has resulted in broad insights into population structure, bacterial evolution, clone emergence and expansion, and the molecular basis of niche adaptation. Furthermore, this information is now being applied clinically in outbreak investigations to inform infection control measures and to determine appropriate treatment regimens. In this review, we summarize some of the broad insights into S. aureus biology gained from the analysis of genomes and discuss future directions and opportunities in this dynamic field of research.
Kleinberg, Michael; Sorkin, John D.; Netzer, Giora; Johnson, Jennifer K.; Shardell, Michelle; Thom, Kerri A.; Harris, Anthony D.; Roghmann, Mary-Claire
We hypothesized that prior colonization with antibiotic-resistant Gram-negative bacteria is associated with increased risk of subsequent antibiotic-resistant Gram-negative bacteremia among cancer patients. We performed a matched case-control study. Cases were cancer patients with a blood culture positive for antibiotic-resistant Gram-negative bacteria. Controls were cancer patients with a blood culture not positive for antibiotic-resistant Gram-negative bacteria. Prior colonization was defined as any antibiotic-resistant Gram-negative bacteria in surveillance or non-sterile-site cultures obtained 2–365 days before the bacteremia. Thirty-two (37%) of 86 cases and 27 (8%) of 323 matched controls were previously colonized by any antibiotic-resistant Gram-negative bacteria. Prior colonization was strongly associated with antibiotic-resistant Gram-negative bacteremia (odds ratio [OR] 7.2, 95% confidence interval [CI] 3.5–14.7) after controlling for recent treatment with piperacillin-tazobactam (OR 2.5, 95% CI 1.3–4.8). In these patients with suspected bacteremia, prior cultures may predict increased risk of antibiotic-resistant Gram-negative bacteremia. PMID:24582582
Tyner, Harmony; Patel, Robin
The purpose of this study was to measure the effect of combined culture of Propionibacterium acnes and Staphylococcus aureus on biofilm formation under different oxygen concentrations. We measured planktonic growth and biofilm formation of P. acnes and S. aureus alone and together under aerobic and anaerobic conditions. Both P. acnes and S. aureus grew under anaerobic conditions. When grown under anaerobic conditions, P. acnes with or without S. aureus formed a denser biomass biofilm than did S. aureus alone. Viable S. aureus was recovered from a16-day old combined P. acnes and S. aureus biofilm, but not a monomicrobial S. aureus biofilm.
Strommenger, Birgit; Bartels, Mette Damkjær; Kurt, Kevin
To elucidate the evolutionary history of Staphylococcus aureus clonal complex (CC) 8, which encompasses several globally distributed epidemic lineages, including hospital-associated methicillin-resistant S. aureus (MRSA) and the highly prevalent community-associated MRSA clone USA300....
Sandra Davi Traverso
Full Text Available Em uma criação composta por 1800 coelhos, 33% das matrizes apresentaram mastite e lesões cutâneas crostosas e purulentas. Estes animais apresentavam-se entre 10 a- 12 meses de idade e em segunda parição. Quinze coelhos afetados foram sacrificados e necropsiados. Na necropsia, além das lesões cutâneas haviam microabscessos em diversos órgãos. Das amostras coletadas isolou-se Staphylococcus aureus subesp. aureus. S. aureus subesp. aureus também foi isolado de "swab" nasal coletado do tratador encarregado de fazer o diagnóstico de gestação nas coelhas. Histologicamente, havia formação de múltiplos abscessos, presença de bactérias gram positivas em vasos sangüíneos e linfáticos, além de êmbolos bacterianos nos tecidos. Nas mamas, observou-se tecido glandular normal associado a abscessos multifocais delimitados.At a commercial rabbitry which was composed of 1800 New Zealand White rabbits, 30% of the does had presented mastitis and purulent cutaneal lesions. The age of the animals ranged from 10 to 12 months and were at the second parturition. At necropsy, microabscesses were observed in several organs. Bacteriological samples collected from affected animals resulted Staphylococcus aureus subesp. aureus.. Additionally, the same agent has been isolated from a nasal swab collected from the person responsible for the pregnancy diagnosis. Histologically, there were multiple abscesses, gram positive bacteria within blood and lymphatic vessels, and bacterial emboli scattered in the tissues. In the mammas, normal glandular tissue associated with multifocal abscesses were observed.
Pierson, D. L.; Chidambaram, M.; Heath, J. D.; Mallary, L.; Mishra, S. K.; Sharma, B.; Weinstock, G. M.
Staphylococcus aureus was isolated over 2 years from Space Shuttle mission crewmembers to determine dissemination and retention of bacteria. Samples before and after each mission were from nasal, throat, urine, and feces and from air and surface sampling of the Space Shuttle. DNA fingerprinting of samples by digestion of DNA with SmaI restriction endonuclease followed by pulsed-field gel electrophoresis showed S. aureus from each crewmember had a unique fingerprint and usually only one strain was carried by an individual. There was only one instance of transfer between crewmembers. Strains from interior surfaces after flight matched those of crewmembers, suggesting microbial fingerprinting may have forensic application.
Bryan J. Berube
Full Text Available Staphylococcus aureus secretes a number of host-injurious toxins, among the most prominent of which is the small β-barrel pore-forming toxin α-hemolysin. Initially named based on its properties as a red blood cell lytic toxin, early studies suggested a far greater complexity of α-hemolysin action as nucleated cells also exhibited distinct responses to intoxication. The hemolysin, most aptly referred to as α-toxin based on its broad range of cellular specificity, has long been recognized as an important cause of injury in the context of both skin necrosis and lethal infection. The recent identification of ADAM10 as a cellular receptor for α-toxin has provided keen insight on the biology of toxin action during disease pathogenesis, demonstrating the molecular mechanisms by which the toxin causes tissue barrier disruption at host interfaces lined by epithelial or endothelial cells. This review highlights both the historical studies that laid the groundwork for nearly a century of research on α-toxin and key findings on the structural and functional biology of the toxin, in addition to discussing emerging observations that have significantly expanded our understanding of this toxin in S. aureus disease. The identification of ADAM10 as a proteinaceous receptor for the toxin not only provides a greater appreciation of truths uncovered by many historic studies, but now affords the opportunity to more extensively probe and understand the role of α-toxin in modulation of the complex interaction of S. aureus with its human host.