Contemporary Drug Treatment of Infective Endocarditis.

May 2013

Sabe MA, Shrestha NK, Menon V.

Source

Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.

Abstract

Infective endocarditis (IE) occurs at a rate of approximately 0.9-6.2 per 100,000 people per year and is associated with a high morbidity and mortality despite advancements in antibiotic and surgical treatments. The general approach to the treatment of IE is initial clinical stabilization, early acquisition of blood cultures, and definitive medical and/or surgical treatment. Surgical consultation should be obtained early when indicated in order to determine the best treatment approach for each individual patient. Surgery is indicated in most cases of prosthetic valve endocarditis, 

Staphylococcus aureus endocarditis, fungal endocarditis, and endocarditis associated with large vegetations (≥10 mm). Initial antibiotic therapy for IE should be targeted to the culprit microorganism; however, in some cases, empiric therapy must be initiated prior to definitive culture diagnosis. Empiric antibiotics should be targeted toward the most likely pathogens, including staphylococci, streptococci, and enterococci species. Here we discuss the recommended antibiotic regimens for the most common causes of IE as indicated by the American Heart Association and European Society of Cardiology. 

In 2008, the ACC/AHA published guideline updates on the treatment of valvular heart disease, which included a focused update on endocarditis prophylaxis. According to the most recent guidelines, the number of patients who require antibiotic prophylaxis has decreased substantially. Treatment of IE should be targeted toward the causative microorganism and must be based on the type and location of valve involved (native, prosthetic, left or right sided), the clinical status of the patient, and the likelihood for clinical success. This requires a collaborative effort from multiple medical specialties including infectious disease specialists, cardiologists, and cardiothoracic surgeons.

PubMed

I have not been well as soon as I am I will again be posting 04/10/13

Cell death from antibiotics without the involvement of reactive oxygen species.

Mar 2013

Liu Y, Imlay JA.

Source

Department of Microbiology, University of Illinois, Urbana, IL 61801, USA.

Abstract

Recent observations have suggested that classic antibiotics kill bacteria by stimulating the formation of reactive oxygen species (ROS). If true, this notion might guide new strategies to improve antibiotic efficacy. In this study, the model was directly tested. Contrary to the hypothesis, antibiotic treatment did not accelerate the formation of hydrogen peroxide in Escherichia coli and did not elevate intracellular free iron, an essential reactant for the production of lethal damage. Lethality persisted in the absence of oxygen, and DNA repair mutants were not hypersensitive, undermining the idea that toxicity arose from oxidative DNA lesions. We conclude that these antibiotic exposures did not produce ROS and that lethality more likely resulted from the direct inhibition of cell-wall assembly, protein synthesis, and DNA replication.

PubMed

Evaluation of drug-resistant Enterobacteriaceae in retail poultry and beef.

Evaluation of drug-resistant Enterobacteriaceae in retail poultry and beef.

Apr 2013

Kilonzo-Nthenge A, Rotich E, Nahashon SN.

Source

Department of Family and Consumer Science, and.

Abstract

There has been increasing concern on the emergence of multidrug-resistant foodborne pathogens from foods of animal origin, including poultry. The current study aimed to evaluate antibiotic-resistant Enterobacteriaceae from raw retail chicken/turkey parts (thigh, wings, breast, and ground) and beef meat (ground and chunks) in Middle Tennessee. Resistance of the collected Enterobacteriaceae to a panel of antibiotics was determined by the Kirby-Bauer disk diffusion test. Retail meats were also assayed for the presence of Salmonella spp. and Escherichia coli O157:H7. Two hundred thirty-seven samples representing 95.2% of the total of 249 samples tested were positive for Enterobacteriaceae. The level of contamination with Enterobacteriaceae in raw meats ranged from 3.26 log cfu/g to 4.94 log cfu/g with significant differences in counts among meat types (P < 0.05). Contamination was significantly greater (P < 0.05) in ground beef, beef chucks, ground chicken, chicken breast, and turkey wings (4.92, 4.58, 4.94, 4.75, 4.13 log cfu/g, respectively) than ground turkey and chicken wings (3.26 and 3.26 log cfu/g, respectively). Klebsiella oxytoca, Serratia spp., E. coli, and Haffnia alvei were most prevalent contaminants at 27.4, 14.3, 12.1, and 11.4%, respectively. Resistance of the Enterobacteriaceae to antimicrobials was most frequent with erythromycin, penicillin, and ampicillin at 100, 89, and 65.8%, respectively. Few (2.7%) of the Enterobacteriaceae were resistant to chloramphenicol. Salmonella spp., E. coli O157:H7, Morganella morganii, Yersinia enterocolitica, and Vibrio parahemolyticus exhibited multiple drug resistance. This investigation demonstrates that raw poultry and beef are potential reservoirs of antibiotic-resistant Enterobacteriaceae.

PubMed

Antibiotic Use in Newborns with Transient Tachypnea of the Newborn.

2013

Weintraub AS, Cadet CT, Perez R, Delorenzo E, Holzman IR, Stroustrup A.

Source

Division of Newborn Medicine, Kravis Children's Hospital, Mount Sinai Medical Center, New York, N.Y., USA.

Abstract

Background: Initiation of empiric antibiotic treatment for possible early-onset sepsis is recommended for late preterm and term neonates with respiratory distress. There is no evidence base to this approach. 

Objectives: To determine the incidence of adverse infectious events in neonates with transient tachypnea of the newborn (TTN) managed with a risk-factor-based restrictive antibiotic use policy. 

Methods: This is a single institution retrospective cohort study of neonates with primary diagnosis of TTN between 2004 and 2010. The relationship between antibiotic exposure and infectious outcomes during the neonatal hospitalization was evaluated. An infectious outcome was defined as pneumonia, bacteremia, clinical sepsis, or death. Analysis included t test, χ(2) test, and analysis of variance as appropriate. 

Results: 745 neonates with TTN met inclusion criteria. None of the 494 antibiotic-naive infants, and 212 of the 251 antibiotic-exposed infants had identifiable risk factors for sepsis. No infectious outcomes occurred in infants who did not receive antibiotics. Eight neonates with TTN received full antibiotic treatment for early-onset sepsis. Each was appropriately identified for early receipt of antibiotics based on historical or clinical risk factors for early-onset sepsis. 

Conclusions: This study suggests that empiric postnatal antibiotictreatment may not be warranted for late preterm and term infants with TTN in the absence of specific infectious risk factors.

PubMed

The Use of Machine Learning Methodologies to Analyse Antibiotic and Biocide Susceptibility in Staphylococcus aureus.

2013

Coelho JR, Carriço JA, Knight D, Martínez JL, Morrissey I, Oggioni MR, Freitas AT.

Source

INESC-ID/IST, Technical University of Lisbon, Lisbon, Portugal.

Abstract

BACKGROUND:

The rise of antibiotic resistance in pathogenic bacteria is a significant problem for the treatment of infectious diseases. Resistance is usually selected by the antibiotic itself; however, biocides might also co-select for resistance to antibiotics. Although resistance to biocides is poorly defined, different in vitro studies have shown that mutants presenting low susceptibility to biocides also have reduced susceptibility to antibiotics. However, studies with natural bacterial isolates are more limited and there are no clear conclusions as to whether the use of biocides results in the development of multidrug resistant bacteria.

METHODS:

The main goal is to perform an unbiased blind-based evaluation of the relationship between antibiotic and biocide reduced susceptibility in natural isolates of Staphylococcus aureus. One of the largest data sets ever studied comprising 1632 human clinical isolates of S. aureus originated worldwide was analysed. The phenotypic characterization of 13 antibiotics and 4 biocides was performed for all the strains. Complex links between reduced susceptibility to biocides and antibiotics are difficult to elucidate using the standard statistical approaches in phenotypic data. Therefore, machine learning techniques were applied to explore the data.

RESULTS:

In this pioneer study, we demonstrated that reduced susceptibility to two common biocides, chlorhexidine and benzalkonium chloride, which belong to different structural families, is associated to multidrug resistance. We have consistently found that a minimum inhibitory concentration greater than 2 mg/L for both biocides is related to antibiotic non-susceptibility in S. aureus.

CONCLUSIONS:

Two important results emerged from our work, one methodological and one other with relevance in the field of antibiotic resistance. We could not conclude on whether the use of antibiotics selects for biocide resistance or vice versa. However, the observation of association between multiple resistance and two biocides commonly used may be of concern for the treatment of infectious diseases in the future.

PubMed

Application of temporarily functional antibiotic-containing bone cement prosthesis in revision hip arthroplasty.

2012

Liu K, Zheng J, Jin Y, Zhao YQ.

Source

Department of Orthopedics, Henan Provincial People's Hospital, No. 7, Weiwu Road, 450003, Zhengzhou, China.

Abstract

PURPOSE:

To investigate the clinical outcome of two-stage revision total hip arthroplasty for infected hip arthroplasty usingantibiotic-impregnated cement prosthesis.

MATERIALS AND METHODS:

 Forty-one patients, who suffered from an infection after hip replacement or internal fixation of femoral neck and trochanteric fractures, were treated with a two-stage revision hip arthroplasty and followed up for an average of 37 months. All the patients were implanted with antibiotic-impregnated cement prosthesis as one-stage treatment and were then managed with two-stage revision hip arthroplasty after 12-24 weeks. During the follow-up, Merle d'Aubigné hip score and Harris score were employed for assessment of hip function, and infection recurrence was observed.

RESULTS:

According to Merle d'Aubigné hip score, 16 patients (39.2 %) were excellent, 19 (46.3 %) were good, 6 (14.6 %) were moderate, and no bad result and the average score was 15.42. Mean Harris score of preoperation, interval period, and postoperation was 46.7, 66.5, and 92.3, respectively. There was no infection recurrence.

CONCLUSION:

Two-stage revision total hip arthroplasty for infected hip arthroplasty using antibiotic-impregnated cement prosthesis has a satisfying clinical outcome.

PubMed

Efficacy of antibiotic prophylaxis in patients undergoing cystoscopy: a randomized clinical trial.

Feb 2013

García-Perdomo HA, López H, Carbonell J, Castillo D, Cataño JG, Serón P.

Source

University of Valle, Cra 35 No 3a-38 Ap 301, Cali, Colombia, herney.garcia@correounivalle.edu.co.

Abstract

OBJECTIVE:

 To establish the efficacy of antibiotic prophylaxis prior to cystoscopy in outpatients in decreasing the incidence of post-procedure urinary tract infection.

STUDY DESIGN AND SETTING:

 A randomized clinical trial in patients (men and women) older than 18 who underwent cystoscopy for any non-urgent indication. The intervention was Levofloxacin 500 mg single dose, and the control was placebo 500 mg single dose made with similar characteristics. The primary outcome was urinary tract infection (UTI) measured 3-10 days after the procedure. It was performed as per protocol analysis.

RESULTS:

 Hundred and thirty-eight patients in each study arm completed the trial. The incidence of UTI in the intervention group was 0.7 % and in the placebo group was 3 % (p = 0.17), and no significant differences were found. The incidence of asymptomatic bacteriuria in the intervention group was 5.8 % and in the control group was 14.5 % (p = 0.01).

CONCLUSIONS:

 No significant differences were found in the use of prophylactic antibiotic compared to placebo to reduce the incidence of UTI in patients who undergo cystoscopy as an outpatient procedure with sterile urine demonstrated by urine culture.

PubMed

Antibiotics for the treatment of hepatic encephalopathy.

Feb 2013

Patidar KR, Bajaj JS.

Source

Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, 1201 Broad Rock Boulevard, Richmond, VA, USA.

Abstract

The treatment of hepatic encephalopathy (HE) is complex and therapeutic regimens vary according to the acuity of presentation and the goals of therapy. Most treatments for HE rely on manipulating the intestinal milieu and therefore antibiotics that act on the gut form a key treatment strategy. Prominent antibiotics studied in HE are neomycin, metronidazole, vancomycin and rifaximin. For the management of the acute episode, all antibiotics have been tested. However the limited numbers studied, adverse effects (neomycin oto- and nephrotoxicity, metronidazole neurotoxicity) and potential for resistance emergence (vancomycin-resistant enterococcus) has limited the use of most antibiotics, apart from rifaximin which has the greatest evidence base. Rifaximin has also demonstrated, in conjunction with lactulose, to prevent overt HE recurrence in a multi-center, randomized trial. Despite its cost in the US, rifaximin may prove cost-saving by preventing hospitalizations for overt HE. In minimal/covert HE, rifaximin is the only systematically studied antibiotic. Rifaximin showed improvement in cognition, inflammation, quality-of-life and driving simulator performance but cost-analysis does not favor its use at the current time. Antibiotics, especially rifaximin, have a definite role in the management across the spectrum of HE.

PubMed

Perioperative Antibiotic Use for Spinal Surgeries in US Children's Hospitals.

Jan 2013 

McLeod LM, Keren R, Gerber J, French B, Song L, Sampson NR, Flynn J, Dormans JP.

Source

1Department of General Pediatrics, Center for Pediatric Clinical Effectiveness, Children's Hospital of Philadelphia, Philadelphia, PA 2Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA 3Division of Pediatric Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA 4Division of Orthopaedic Surgery, Children's Hospital of Philadelphia, Philadelphia, PA.

Abstract

ABSTRACT: Study Design: Retrospective cohort study using the Pediatric Health Information Systems (PHIS) database.

Objective: To describe longitudinal patterns of prophylactic antibiotic use and determinants of antibiotic choice for spinal fusion surgeries performed at US children's hospitals.Summary of Background Data: Surgical Site Infections (SSIs) account for a significant proportion of post-spinal surgery complications, particularly among children with complex conditions such as neuromuscular disease. Antimicrobial prophylaxis with intravenous (IV) cefazolin or cefuroxime has been a standard practice, but postoperative infections caused by organisms resistant to these antibiotics are increasing in prevalence. Studies describing the choice of antibiotic prophylaxis for pediatric spinal surgery are lacking.

Methods: We included children 6 months to 18 years of age discharged from 37 US children's hospitals between January 1, 2006 - June 30, 2009 with 1) an ICD9-CM procedure code indicating a spinal fusion and 2) combinations of diagnosis codes indicating adolescent idiopathic scoliosis (AIS, n = 5,617) or neuromuscular scoliosis (NMS, n = 3,633). After identifying antibiotics ordered on the operative day, we described variation in broad-spectrum antibiotic use over time, and measured associations between patient/surgery characteristics and antibiotic choice.

Results: Prophylactic antibiotic choice varied across hospitals and over time. Broad-spectrum antibiotics were used in 37% of AIS and 52% of NMS operations. Seven (19%) hospitals used broad spectrum coverage for greater than 80% of all cases. For NMS procedures, broad-spectrum antibiotic use was associated with patient characteristics known to be associated with high SSI risk. Use of vancomycin and broad gram-negative agents increased over time.

Conclusion: Broad-spectrum antimicrobial prophylaxis varied across hospitals, and was often associated with known risk factors for SSI. These results highlight the need for future studies comparing the effectiveness of various prophylaxis strategies, particularly in high risk subgroups. This research can inform the development of best practice for SSI prevention in spinal fusion procedures.

PubMed

Factors Affecting the Prescribing Patterns of Antibiotics and Injections

2012

Kyung-Hyun Choi, Sang-Min Park, Ju-Hyun Lee,  Soonman Kwon¹

Author information ► Article notes ► Copyright and License information ►

ABSTRACT

There are serious problems concerning the inadequate prescription of antibiotics and overuse of injections in primary care. However, the determinants of prescription patterns in Korea are not well-documented. To examine the area characteristics affecting the prescription of antibiotics and injections in primary care practices in the treatment of respiratory tract infections (RTIs), a nationwide cross-sectional study was performed in all 250 administrative districts of Korea. The outcome was modeled as a binary variable: over-prescription or not compared with the nation-wide average. Over-prescription of antibiotics was associated with the ratio of specialists to general physicians and over-prescription in previous years in the area (adjusted odds ratio [aOR], 4.8; 95% confidence interval [CI] 1.5-14.8; and aOR, 12.0; 95% CI 5.5-25.9, respectively). Over-use of injections was associated with younger population, urban living and the number of hospital beds in the area (aOR, 0.2; 95% CI 0.1-0.4; aOR, 0.3; 95% CI 0.1-0.8; and aOR, 0.4, 95% CI 0.2-0.9; respectively). There were differences in the prescribing patterns in different districts; prescription patterns were affected more by supply factors than by demand factors. Highly competitive medical environment associated with supply factors is a significant determinant of prescription patterns in Korea.

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NIH - Journal of Korean Medical Science

Pathogen- and Host-Directed Anti-Inflammatory Activities of Macrolide Antibiotics

2012

Helen C. Steel,  Annette J. Theron,  Riana Cockeran,  Ronald Anderson,  and Charles Feldman 

Author information ► Article notes ► Copyright and License information ►

ABSTRACT

Macrolide antibiotics possess several, beneficial, secondary properties which complement their primary antimicrobial activity. In addition to high levels of tissue penetration, which may counteract seemingly macrolide-resistant bacterial pathogens, these agents also possess anti-inflammatory properties, unrelated to their primary antimicrobial activity. Macrolides target cells of both the innate and adaptive immune systems, as well as structural cells, and are beneficial in controlling harmful inflammatory responses during acute and chronic bacterial infection. These secondary anti-inflammatory activities of macrolides appear to be particularly effective in attenuating neutrophil-mediated inflammation. This, in turn, may contribute to the usefulness of these agents in the treatment of acute and chronic inflammatory disorders of both microbial and nonmicrobial origin, predominantly of the airways. This paper is focused on the various mechanisms of macrolide-mediated anti-inflammatory activity which target both microbial pathogens and the cells of the innate and adaptive immune systems, with emphasis on their clinical relevance.

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NIH - Mediatotors of Inflammation

Present and future of prophylactic antibiotics for severe acute pancreatitis

2012

Kun Jiang, Wei Huang, Xiao-Nan Yang, and Qing Xia

Author information ► Article notes ► Copyright and License information 

Abstract

AIM: 

To investigate the role of prophylactic antibiotics in the reduction of mortality of severe acute pancreatitis (SAP) patients, which is highly questioned by more and more randomized controlled trials (RCTs) and meta-analyses.

METHODS: 

An updated meta-analysis was performed. RCTs comparing prophylactic antibiotics for SAP with control or placebo were included for meta-analysis. The mortality outcomes were pooled for estimation, and re-pooled estimation was performed by the sensitivity analysis of an ideal large-scale RCT.

RESULTS:

Currently available 11 RCTs were included. Subgroup analysis showed that there was significant reduction of mortality rate in the period before 2000, while no significant reduction in the period from 2000 [Risk Ratio, (RR) = 1.01, P = 0.98]. Funnel plot indicated that there might be apparent publication bias in the period before 2000. Sensitivity analysis showed that the RR of mortality rate ranged from 0.77 to 1.00 with a relatively narrow confidence interval (P < 0.05). However, the number needed to treat having a minor lower limit of the range (7-5096 patients) implied that certain SAP patients could still potentially prevent death by antibiotic prophylaxis.

CONCLUSION:

Current evidences do not support prophylactic antibiotics as a routine treatment for SAP, but the potentially benefited sub-population requires further investigations.

NIH-World Journal of Gastroenterology

The Cpx Stress Response Confers Resistance to Some, but Not All Bactericidal Antibiotics.

Jan 2013

Mahoney TF, Silhavy TJ.

Source

Princeton University, Department of Molecular Biology Princeton, NJ 08544.

Abstract

It has recently been suggested that bactericidal antibiotics including aminoglycosides (AGAs), and toxic small molecules, such as hydroxyurea (HU), kill bacteria the same way; namely, by generating reactive oxygen species (ROS) via a process requiring activation of the Cpx stress response. We suggest an opposite, protective role for Cpx. We have confirmed the initial finding that cpxA null mutations confer resistance to HU. However, the two-component sensor CpxA is both a kinase and a phosphatase, and previous work from our lab has shown that removing CpxA can activate the stress response owing to buildup of the phosphorylated response regulator (CpxR∼P) that occurs in the absence of the phosphatase activity. We show that a dominant cpxA* mutation that constitutively activates the Cpx stress response confers a high level of resistance to both HU and AGAs in a CpxR dependent manner. In contrast, inactivating the CpxR response regulator, by mutating the phosphorylation site (D51A) or the putative DNA-binding motif (M199A) does not increase resistance to HU or AGAs. Taken together, these results demonstrate that activation of the Cpx stress response can protect cells from HU and AGAs. However the Cpx response does not increase resistance to all classes of bactericidal antibiotics, as the cpxA* mutants are not significantly more resistant to fluoroquinolones or β-lactams than wild-type cells. Thus, it seems unlikely that all bactericidalantibiotics kill by the same mechanism.

PubMed

Distribution of anaerobes in periodontal abscess and its resistance to antibiotics.

Dec 2012

[Article in Chinese]

He JL, Yu LY, Chen JZ.

Source

Department of Stomatology, Huashan Hospital, Fudan University, Shanghai 200040, China. Email: wuyu1984@hotmail.com.

Abstract

OBJECTIVE:

To isolate and culture the predominant anaerobes from the periodontal abscesses, and to test the antibiotic susceptibility and drug resistant genes of the strains.

METHODS:

The isolated strains were identified by both API20A biochemical method and polymerase chain reaction (PCR) method. The antibiotic susceptibility test was performed by agar dilution method. The resistant genes of the drug-resistant strains obtained were screened by PCR.

RESULTS:

The anaerobes were detected in 48% (28/58) of the samples and Prevotella melaninogenica (Pm) was mostly identified in 43% (12/28). API20A biochemical method had 82% (23/28) agreement with the 16SrRNA method in identification rate. Anaerobes were resistant to metronidazole, clindamycin and cefmetazole. The erythromycin-resistant methylase genes F (ermF) gene was detected in three of eight clindamycin resistant strains. None of them was found coded on bacterial plasmids. However, no metronidazole resistant gene was detected on drug resistant strains.

CONCLUSIONS:

Pm was the predominant species dectected in the periodontal abscess of the patients. The antibiotic agents should be used based on the genotypes and general condition of the patients.

PubMed