H. Bradford Hawley

Multicenter collaborative evaluation of a standardized serum bactericidal test as a prognostic indicator in infective endocarditis

One hundred twenty-nine patients with bacterial endocarditis were evaluated in a multicenter collaborative study to determine whether a standardized serum bactericidal test could predict the outcome of the infection. All centers used a microdilution test method that defined all known test variables, including inoculum size, culture medium, dilution technique, incubation time, method of subculture, and bactericidal endpoint. Peak serum bactericidal titers of 1:64 or more and trough serum bactericidal titers of 1:32 or more predicted bacteriologic cure in all patients. The traditionally recommended serum bactericidal titer of 1:8 had statistically significant predictive accuracy at trough antibiotic levels only. The serum bactericidal test was a poor predictor of bacteriologic failure and ultimate clinical outcome, which depends on many factors. Wider recognition by physicians and clinical microbiologists that this in vitro test of antimicrobial activity can accurately predict bacteriologic success but cannot accurately predict either bacteriologic failure or clinical outcome could lead to a better consensus about its appropriate use. On the basis of the results of this study, peak serum bactericidal titers of 1:64 or more and trough serum bactericidal titers of 1:32 or more are recommended to provide optimal medical therapy for infective endocarditis.

Multicenter Collaborative Evaluation of a Standardized Serum Bactericidal Test as a Predictor of Therapeutic Efficacy in Acute and Chronic Osteomyelitis

Forty-eight episodes of osteomyelitis, 30 acute and 18 chronic, were evaluated in a prospective multicenter collaborative study to determine whether a standardized serum bactericidal test could predict outcome of infection. All centers used a microdilution test method that defined the recognized important test variables, including inoculum size, culture medium, dilution technique, incubation time, method of subculture, and bactericidal endpoint. In patients with acute osteomyelitis, peak serum bactericidal titers had no predictive value; however, trough titers of 1:2 or greater accurately predicted cure, whereas trough titers of less than 1:2 predicted therapeutic failure. In patients with chronic osteomyelitis, peak serum bactericidal titers of 1:16 or greater and trough titers of 1:4 or greater accurately predicted cure, whereas peak titers of less than 1:16 and trough titers of less than 1:2 accurately predicted failure. It is concluded that this standardized serum bactericidal test provides good prognostic information in patients with osteomyelitis, and it is recommended that patients with acute osteomyelitis have serum bactericidal titers of 1:2 or greater at all times and that patients with chronic osteomyelitis have serum bactericidal titers of 1:4 or greater at all times.

APACHE II and ISS scores as predictors of nosocomial infections in trauma patients.

BACKGROUND Nosocomial infections affect more than 2 million patients annually in the United States at a cost of

Candidal Suppurative Peripheral Thrombophlebitis

4.5 billion. The aim of this study is to identify the role of the APACHE II score and the Injury Severity Scale (ISS) as independent predictors of nosocomial infections in trauma patients admitted to the intensive care unit (ICU). METHODS A retrospective chart review of 113 trauma patients admitted to the ICU was conducted by an infectious disease physician. Demographic data and incidence of nosocomial infections were recorded. Multivariate logistic regression analysis was used to determine variables that are predictive of the occurrence of nosocomial infections. RESULTS Presence or absence of intubation, ICU length of stay, APACHE II score, and ISS were related to the presence of infections; however, only the ICU length of stay was an independent predictor of a nosocomial infection, with an odds ratio of 1.81. By linear regression, 17% of the variance in the ICU duration of stay was a result of the APACHE II score in patients with a score >/=5. CONCLUSION APACHE II score and ISS score were not good predictors of the incidence of nosocomial infections in trauma patients admitted to the ICU, but the APACHE II score has a modest correlation with the duration of stay in the ICU. A stratified cohort study could identify the subset of patients for which the APACHE II score predicts a prolonged stay in the ICU, thus an increased risk of infection.

Enterohemorrhagic Escherichia coli and Other Shiga Toxin-producing E. coli.

Transient candidemia is common with prolonged intravenous therapy. Sustained candidemia, however, usually indicates a persistent focus of infection. A complication of intravenous therapy not previously emphasized is persistent candidemia caused by candidal suppurative peripheral thrombophlebitis. We report six cases that appeared during intravenous therapy: the infection was characterized by a thrombosed peripheral vein at an intravenous site with manifestations for candida septicemia with or without disseminated candidiasis. In two patients, the source of the process was occult; the examination showed only a thrombosed noninflamed vein. In all cases, surgical exploration showed the thrombosed veins to be suppurative with positive cultures for Candida. Special stains, moreover, showed Candida in the luminal clot and the vascular wall. In the five surviving patients, cure was achieved by excision of the affected vein. Four received a short course of amphotericin B and 5-fluorocytosine, and one patient received amphotericin B only.

Susceptibility of Stenotrophomonas maltophilia to Moxifloxacin, Trovafloxacin, Ofloxacin and Ciprofloxacin

Although not indicated in the book’s title, this is a second edition of a 1998 text by the same publisher with new editors. The book is a collection of articles by >50 authors that appeared in Microbiology Spectrum. They were published in no particular order and are available online without charge. The editors have arranged the 27 articles into 10 sections. The scope is wide and the organization is logical, but because this is not truly a textbook, there is considerable overlap of information between chapters. The book begins with a short overview of Shiga toxin–producing E. coli (STEC). This brief introduction starts with Kiosha Shiga’s discovery of the agent of bacterial dysentery in 1898 and progresses through the subsequent discoveries of the toxins and virulence factors. A capsule discussion of hemolytic uremic syndrome (HUS), hemorrhagic colitis, and the European outbreak caused by E. coli O104:H4 is followed by some concluding remarks on the present state of STEC research. The microbiology section begins with a chapter explaining the confusing assortment of classification schemes, which include 472 serotypes, 6 pathotypes, and 5 seropathotypes. Multilocus sequence typing adds hundreds of unique types to the mix. Next is a chapter on Shiga toxin with some well-done color diagrams of toxin structure. The 2 toxin branches (Stx1 and Stx2) containing >100 variants are considered with respect to genetics, action, and clinical disease. The section concludes with a chapter on genomics and the study of outbreaks usingmolecular methodology. The next 5 chapters on pathogenesis provide for some of the most interesting and challenging reading. They cover the genetics andmolecular attributes of STEC that allow for host adaption and disease causation. Virulence factors, key genes, and pathogenicity islands are presented in detail. There is a chapter on animal models as well as a fascinating chapter on how STEC uses gene regulation to adapt to and exploit a variety of host environments. Sections 4 and 5 relate to the epidemiology and detection of STEC. Surveillance systems in Japan, Europe, and the United States are explained. The system used in the United States is called FoodNet and was established in 1995. It uses data from 10 state health departments whose surveillance area includes 18% of the US population. Techniques for culture, cytotoxicity tests, immunological assays, and polymerase chain reaction are detailed and referenced. Cattle are regarded as the natural reservoirs of STEC, but other ruminants are also important. The infectious dose for cattle is low (300 organisms), and the rectoanal junction is the site of colonization in the asymptomatic, organismshedding cattle. It is interesting that a type of fimbria on the surface of E. coli, called curli, not only helps the organism bind to host intestinal cells, but also assists the organism in binding to vegetables and stainless steel plus promotes resistance to chlorine! Contaminated water troughs for cattle are important in maintaining STEC in herds as the organism can persist in troughs for >4 months. Sections 6 and 7 explore the pathophysiology of STEC disease, host determinants, and the latest treatments of disease. Escherichia coli O157:H7 is acid tolerant with a low infecting dose for humans (as little as 10 organisms). Stx2a is a very potent toxin and is 40–400 times more potent than the original toxin from Shigella dysenteriae (Stx1). Additionally, low gastric acidity (including drug therapy), use of antibiotics, and use of antimotility agents can contribute to the vulnerability of the host to disease. There is a section on prevention and control. A preharvest food safety chapter examines the various reservoirs of STEC, especially involving beef cattle. Cattle vaccinations and other control measures have reduced but not yet eliminated STEC and disease transmission to humans. There are some rather gruesome descriptions of abattoir practices and their contributions to contamination. Improvements in slaughterhouse procedures and vaccines for both humans and cattle are discussed. When serious STEC disease was thought to be associated mainly with pathogenic strains of E. coli O157:H7, along came the 2011 European outbreak of disease caused by a novel strain of E. coli O14:H4. The outbreak resulted in 46 deaths and 782 cases of HUS. The new clone dramatically demonstrated the ability of various E. coli strains to exchange genetic information and acquire new virulence factors. A chapter is devoted to the characteristics of this strain. One of the editors concludes the book with a short chapter suggesting knowledge gaps and areas for future research. In summary, this multiauthored text provides a compilation of knowledge and research on STEC up through 2013. The book is thoroughly referenced and beautifully printed in the United States. It will be of interest to individuals concerned with various aspects of STEC who wish Clinical Infectious Diseases

Knowledge acquisition: an infectious diseases perspective

The Gram-negative bacterium Stenotrophomonas maltophilia is increasingly recognised as an important cause of nosocomial infection.[1] Management of S. maltophilia-associated infection is problematic because many strains of the bacterium manifest resistance to multiple antibiotics. Most studies have supported a combination of cotrimoxazole (trimethoprimsulfamethoxazole) and either ticarcillin/clavulanic acid or an extended spectrum cephalosporin as treatments of choice for infections caused by this organism.[1-4] The activity of quinolones against S. maltophilia strains varies. Previous in vitro studies with small numbers of isolates have shown that the newer quinolones, such as clinafloxacin, sparfloxacin, trovafloxacin and moxifloxacin, appear to be more active against this bacterium than the older agents in this class.[1-8] This study examines the in vitro susceptibility of 105 clinical isolates of S. maltophilia to the newer quinolones, moxifloxacin and trovafloxacin, compared with the older quinolones, ofloxacin and ciprofloxacin.

The etiology and treatment of infective prostatitis

A study was undertaken to evaluate the knowledge acquisition in Infectious Diseases during a one-month rotation completed by fourth-year medical students and residents. Fifty fourth-year medical students and 112 residents (internal medicine = 86, internal medicine/pediatrics = 18, orthopedics = 6, family medicine = 2) completed a one-month rotation in Infectious Diseases. The rotation took place between 1990 and 1998. The setting was community hospitals affiliated with a community-based medical school and medical school-sponsored residency programs. Medical students and residents completed a 103-item objective test (multiple choice, multiple true-false, matching) on a pre-test-post-test basis.The test covered 10 content areas including antibiotics, endocarditis, febrile neutropenia, HIV disease, meningitis, osteomyelitis, pneumonia, postoperative fever, sexually transmitted diseases and urinary tract infections. The mean score on the Infectious Diseases knowledge test increased from 65.8% to 77.4% for med...

Stenotrophomonas maltophilia infection and colonization in the intensive care units of two community hospitals: A study of 143 patients.

Summary Prostatitis is a common disorder which remains poorly understood. The causes of nonbacterial prostatitis and prostadynia are unclear, but new molecular methods show promise in uncovering some infectious agents. Bacterial prostatitis constitutes 5 to 10% of the total cases of prostatitis, but causative organisms are well-delineated. Unfortunately the high initial therapeutic success rates using antibiotics directed against these susceptible organisms are too often associated with high relapse rates. Quinolones, such as ciprofloxacin, ofloxacin, and trovafloxain, are the agents of choice for antibacterial therapy of prostatitis. More information is needed concerning the antibiotic levels and activity in infected prostatic tissue and secretions, optimum duration of therapy, and benefit of long-term suppressive therapy.