Gram Positive Cocci

4 Key excerpts on "Gram Positive Cocci"

• 

  No longer available |Learn more

  Microbiology for Surgical Technologists

  • Margaret Rodriguez(Author)
  • 2016(Publication Date)
  • Cengage Learning EMEA

    (Publisher)

  This evening he was researching the cases so he would know about them and how he might best be prepared. 1. What age group would his patients most likely be in? 2. What would the pre-operative diagnosis be for these cases? 3. Which part of the anatomy is involved and where will the incision(s) be made? 4. Which bacteria typically cause the condition that requires the surgical intervention? Under the Microscope Figure 12-16 This digitally colorized scanning electron micrograph image depicts large numbers of Gram-positive Enterococcus faecalis sp. bacteria. Courtesy of CDC/Pete Wardell Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. CHAPTER 12 Gram-Positive Cocci 181 Key Terms and Definitions Biofilm: A thin, gelatinous-like film secreted by bacterial cells that forms around multiple cells, creating microcolonies on surfaces such as teeth or implanted devices and in lumens of indwelling catheters, difficult to eliminate even with antibiotic therapy. Boils: A large, raised, acutely inflamed skin lesion filled with pus; also known as a furuncle. Bullous: Characterized by eruption of blisters (bullae)/skin crusting without blisters; forms of the skin disease impetigo, with nonbullous impetigo being the more contagious form. Carbuncles: Circumscribed (focused) sites of staphylococcal subcutaneous tissue infection containing pus that eventually discharge to the surface of the skin.

  Sign up to read

  Learn more about book
• 

  eBook - ePub

  The Mouse in Biomedical Research

  Diseases

  • (Author)
  • 2006(Publication Date)
  • Academic Press

    (Publisher)

  Chapter 16

  Aerobic Gram-Positive Organisms

  Cynthia Besch-Williford and Craig L. Franklin

  I. Introduction

  II. Staphylococcus

  A. Bacterial Properties B. Cultivation C. Strains D. Clinical Manifestations E. Epizootiology F. Diagnosis G. Treatment and Control

  III. Streptococcus

  A. Bacterial Properties B. Cultivation C. Strains D. Clinical Manifestations E. Epizootiology F. Diagnosis G. Control and Prevention

  IV. Corynebacterium

  A. Corynebacterium bovis

  1 Bacterial Properties 2 Cultivation 3 Strains 4 Clinical Manifestations 5 Epizootiology 6 Diagnosis 7 Treatment and Control

  B. Corynebacterium kutscheri

  1 Bacterial Properties 2 Cultivation 3 Strains 4 Clinical Manifestations 5 Epizootiology 6 Diagnosis 7 Treatment and Control

  V. Summary References

  I. INTRODUCTION

  Gram-positive bacterial infections in mice are among the most common causes of sporadic infections in research colonies, but the lack of recent reports of disease under-represents disease prevalence in contemporary research facilities. Clinical expression of infection is typical of pyogenic disease, with clinical signs that range from localized conjunctivitis and dermatitis to fulminate septicemia. Treatment of infections is often instituted to salvage valuable mutant mice until studies are concluded or until mice can be rederived. Many grampositive bacteria that cause disease in mice are commensals on the skin and mucous membranes of other laboratory animals and people. Housing and handling procedures must be implemented to minimize transmission by contact with colonized mice or contaminated fomites, including materials used in experimentation. In this chapter, we discuss gram-positive micrococci and corynebacteria as pathogens of concern to researchers who use mice.

  II. STAPHYLOCOCCUS

  Staphylococci are hardy gram-positive, coccoid bacteria that commonly colonize the skin, mammary glands, mucous membranes, and gastrointestinal tract of man and animals, including laboratory mice ( Bannerman 2003 ). Surveys of staphylococcal carriage revealed cutaneous colonization of about 90% of healthy people and approximately 75% of conventional laboratory mice (

  Nagase et al. 2002

  ). The predominant isolate from man was Staphylococcus epider-midis, with S. warneri as a distant second. In contrast, Staphylococcus xylosus and S. sciuri were most often recovered from mice. In both man and mouse, fewer than 10% carried Staphylococcus aureus . While the distribution of staphylococcal species is quite different between man and mouse, one similarity is that the predominant staphylococcal skin commensals do not produce coagulase. Coagulase-negative isolates were once thought to be nonpathogenic. When coagulase-negative staphylococci were recovered from wounds, especially cutaneous wounds, it was difficult to determine if these bacteria were bystanders or pathogens. Isolation of coagulase-negative staphylococci from biofilms on indwelling medical devices and from pyogenic infections in immunosuppressed mice and people suggest these staphylococci are pathogenic, but have a different virulence factor repertoire than those of the well-studied coagulase-positive staphylococci such as S. aureus ( Bannerman 2003

  Sign up to read

  Learn more about book
• 

  eBook - ePub

  Microbial Food Safety

  A Food Systems Approach

  • Charlene Wolf-Hall, William Nganje(Authors)
  • 2017(Publication Date)
  • CAB International

    (Publisher)

  The Gram reaction is a first clue, and then other clues like the microscopic cell morphology or shape and placement can provide other clues. The remainder of this chapter will focus on those bacterial pathogens of most concern in foods that fall under the category of Gram positive, and Chapter 7 will focus on those that are Gram negative. Gram-Positive Bacteria of Concern in Food Safety The following descriptions further classify Gram-positive bacteria of concern for food safety into two additional categories: spore formers and non-spore formers. The spore formers Spore-forming bacteria are all Gram-positive rods (see Fig. 6.1). Spore-forming bacteria have the capability to alter their cells to more hardy forms, or spores that can survive extreme environmental conditions. Spores are dormant and essentially biologically inactive. Bacterial spores are of most concern in foods where the food has been processed previously, reducing the competitive microbial flora. After processing, if the environmental conditions are favorable, the spores can germinate; the bacteria become biologically active and can multiply rapidly. For a deeper understanding of the biology of spore-forming bacteria, see Setlow and Johnson (2013). The bacterial spore formers of most concern for foodborne illness include Bacillus cereus, Clostridium botulinum, and Clostridium perfringens. Fig. 6.1 Illustration of culture specimens of Clostridium botulinum depicting the rods of spore-forming bacteria that sometimes appear to have bulges where the spores are forming (CDC PHIL, 2014). Bacillus cereus Microscopic morphology: This species is a Gram-positive spore former, with vegetative cells that appear as large rods. The genus name Bacillus is derived from the Latin word bacillum, which means staff or walking stick

  Sign up to read

  Learn more about book
• 

  eBook - ePub

  Foodborne Pathogens

  Hazards, Risk Analysis and Control

  • Clive de W Blackburn, Peter J McClure(Authors)
  • 2009(Publication Date)
  • Woodhead Publishing

    (Publisher)

  22

  Staphylococcus aureus and other pathogenic Gram-positive cocci

  M. Adams    University of Surrey, UK

  Abstract

  The role of Gram-positive cocci as agents of foodborne illness is described along with methods for their control. The chapter focuses primarily on staphylococcal food poisoning caused by Staphylococcus aureus , but the enterococci and pathogenic streptococci that can be transmitted by food are also discussed.

  Key words Staphylococcus aureus enterococci Streptococcus

  22.1 Introduction

  This chapter discusses a number of bacteria which share a Gram-positive coccoid morphology and an association with foodborne illness. It focuses primarily on Staphylococcus aureus since it is the most significant cause of foodborne illness among these organisms.

  Other organisms discussed here are the enterococci which are commonly found in the gastrointestinal tract of humans and animals and in a variety of foods. These are associated with a variety of infections, and have been implicated in outbreaks of foodborne illness in the past. Some of the evidence relating to this is discussed here. Finally, some other pathogenic streptococci which are occasionally spread by food are considered.

  22.2 Staphylococcus aureus and other enterotoxigenic staphylococci

  22.2.1 The organism and its characteristics

  In recent years Staph. aureus has attracted much attention and notoriety as a cause of human infections, and it was in this role that it was first described by Ogston in 1882. He coined the name staphylococcus to describe the microscopic appearance of pyogenic bacteria which resembled bunches of grapes. The first recognised description of its association with foodborne illness came very shortly afterwards when Vaughan identified coccoid bacteria as responsible for illness caused by cheese and, later, ice cream in Michigan (Vaughan, 1884 ; Anon., 1886 ). He also isolated and crystallised a putative toxin which he named tyrotoxicon. Subsequent reports in the early 20th century associated the organism with illness from meat products in Belgium and mastitic milk in the Philippines, and in 1930 Dack, investigating an outbreak caused by a cream filled cake, showed that staphylococcal food poisoning was caused by a filterable enterotoxin (

  Dack et al

  Sign up to read

  Learn more about book