DOCSLIB.ORG

Identification and Antibiotic Susceptibility of Coagulase Negative

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Identification and Antibiotic Susceptibility of Coagulase Negative Br J Ophthalmol 1999;83:771–773 771 Identification and antibiotic susceptibility of coagulase negative staphylococci isolated in Br J Ophthalmol: first published as 10.1136/bjo.83.7.771 on 1 July 1999. Downloaded from corneal/external infections Antonio Pinna, Stefania Zanetti, Mario Sotgiu, Leonardo A Sechi, Giovanni Fadda, Francesco Carta Abstract microbiology laboratory, identification of sta- Aims—To identify and determine anti- phylococci is often limited to a rapid screening biotic susceptibility of coagulase negative test for S aureus, while non-S aureus isolates are staphylococci (CoNS) isolated from pa- simply reported as CoNS species. Apart from tients with chronic blepharitis, purulent being a common component of the normal conjunctivitis, and suppurative keratitis. ocular flora, these bacteria have also been Methods—A retrospective review of all reported to cause chronic blepharitis,23 culture positive cases of chronic blephari- conjunctivitis,45and keratitis.67 tis, purulent conjunctivitis, and suppura- Despite being important ocular pathogens, tive keratitis between July 1995 and CoNS have so far received little attention in December 1996 was performed. Cases in ophthalmology. The purpose of this study was which CoNS were the sole isolates were to identify and determine antibiotic suscepti- analysed. Species identification was per- bility of CoNS isolated from patients with formed by using a commercially available chronic blepharitis, purulent conjunctivitis, standardised biochemical test system. and suppurative keratitis. Antibiotic susceptibility to penicillin, gentamicin, tetracycline, erythromycin, ciprofloxacin, and teicoplanin was deter- Materials and methods mined by agar disc diVusion (Kirby– A retrospective review of all culture positive Bauer method). Teicoplanin resistance cases of chronic blepharitis, purulent conjunc- was confirmed by agar dilution. tivitis, and suppurative keratitis between July Results—42 Staphylococcus epidermidis, 1995 and December 1996 was performed. All four S warneri, three S capitis,twoS case in which CoNS were the sole isolates were hominis, one each of S xylosus, S simu- selected. In total 55 clinically significant strains lans, S equorum, and S lugdunensis were of CoNS from 45 outpatients were analysed. Thirty one CoNS were from eyes with chronic identified. 37 CoNS were penicillin resist- http://bjo.bmj.com/ ant, 12 gentamicin resistant, 28 tetracy- blepharitis, 12 from eyes with purulent con- cline resistant, 18 erythromycin resistant, junctivitis, and 12 from eyes with suppurative keratitis. Eight patients had bilateral chronic Institute of four ciprofloxacin resistant, and one te- Ophthalmology, icoplanin resistant (MIC, 32 µg/ml). In blepharitis and two bilateral acute conjunctivi- University of Sassari, total, 16 strains were resistant to three or tis; in the remaining 35, ocular infection Sassari, Italy more antibiotics. involved one eye only. A Pinna Conclusion—Species of CoNS apart from Specimens were collected from the inferior M Sotgiu fornix of the palpebral conjunctiva, lid mar- on October 3, 2021 by guest. Protected copyright. F Carta S epidermidis may be isolated from patients with corneal and external infec- gins, and corneal ulcers using Dacron swabs. Department of tion. Antibiotic susceptibility of CoNS is Three swabs were used for each eye. The first Biomedical Sciences, unpredictable and multiresistant strains swab was inoculated into thioglycolate broth Section of are common. As a result, antibiotic sus- supplemented with sterile fetal calf serum Experimental and ceptibility testing should be performed in (10% vol/vol) for the detection of aerobic and Clinical Microbiology, all cases of clinically significant ocular anaerobic bacteria. Tubes were incubated at University of Sassari, 37°C for at least 72 hours. Subcultures were Sassari, Italy infections caused by CoNS. S Zanetti (Br J Ophthalmol 1999;83:771–773) performed by using chocolate, mannitol salt, L A Sechi and McConkey agar plates. The second swab was rolled on a Sabouraud dextrose agar plate Institute of Members of the genus Staphylococcus are non- for the detection of fungi. The third swab was Microbiology, motile, non-spore forming, usually unencapsu- inoculated into 4SP transport medium for Università Cattolica lated Gram positive cocci; most species are . Cultures for the detec- del Sacro Cuore, Chlamydia trachomatis Rome, Italy facultative anaerobes. They are indigenous tion of bacteria, fungi, and C trachomatis were G Fadda microflora of the skin and mucous membranes performed according to a previously recom- of humans and are a common cause of eyelid, mended protocol.9 CoNS were identified by Correspondence to: Dr conjunctival, or corneal infection.1–7 The pres- Gram staining, colony morphology on agar Antonio Pinna, Istituto di 8 Clinica Oculistica, Università ence or absence of coagulase, an enzyme that plates, and slide test for coagulase. degli Studi di Sassari, Viale clots plasma, divides the Staphylococcus species Over the 18 month period, as they were iso- San Pietro 43 A, 07100 into two broad groups: the coagulase positive lated, CoNS were immediately speciated. Spe- Sassari, Italy. staphylococci and coagulase negative staphylo- cies identification was performed by using the Accepted for publication cocci (CoNS). Fourteen species of CoNS are API ID 32 Staph (bioMérieux, La Balme les 4 February 1999 currently recognised as human isolates.8 In the Grottes, Montalieu Vercieu, France), a stand- 772 Pinna, Zanetti, Sotgiu, et al Table 1 Species identification of coagulase negative Table 3 Multiple antibiotic resistance of coagulase staphylococci isolated from patients with chronic blepharitis, negative staphylococci purulent conjunctivitis, and suppurative keratitis Br J Ophthalmol: first published as 10.1136/bjo.83.7.771 on 1 July 1999. Downloaded from Resistance to Number (%) of isolates No of cases 2 antibiotics 12 (22) Species (No of Chronic Purulent Suppurative 3 antibiotics 11 (20) isolates) blepharitis conjunctivitis keratitis 4 antibiotics 3 (5) 5 antibiotics 1 (2) S epidermidis (42) 21 12 9 6 antibiotics 1 (2) S warneri (4) 4 — — S capitis (3) 2 — 1 S hominis (2) 2 — — Strains which showed multiple antibiotic S xylosus (1) — — 1 S simulans (1) 1 — — resistance were stored in nutrient broth with S equorum (1) 1 — — 15% glycerol at −80°C for further reference. S lugdunensis (1) — — 1 Results ardised and miniaturised biochemical test sys- Forty two S epidermidis, four S warneri, three S tem with a specially adapted database. The capitis,twoS hominis, one each of S xylosus, S API ID 32 Staph system strip consists of 32 simulans, S equorum, and S lugdunensis were cupules, 26 of which contain dehydrated identified (Table 1). The results of antibiotic biochemical media for colorimetric tests. The susceptibility testing are given in Tables 2 and tests included acid production from glucose, 3. Overall, 37 (67%) isolates were resistant to fructose, mannose, maltose, lactose, trehalose, penicillin, 12 (22%) to gentamicin, 18 (33%) mannitol, raYnose, sucrose, N-acetyl- to erythromycin, four (7%) to ciprofloxacin, glucosamine, turanose, ribose, arabinose, and one (2%) to teicoplanin. Susceptibility to cellobiose; decarboxylation of arginine and tetracycline was tested on 49 isolates; 28 (57%) ornithine; production of urease, â glucuroni- were found to be tetracycline resistant. On the dase, â galactosidase, acetoin, alkaline phos- whole, eight (15%) strains were sensitive to all phatase, arginine arylamidase, and antibiotics, whereas 16 (29%) were resistant to pyrrolidonyl-arylamidase; hydrolysis of aescu- three or more antibiotics. One strain of S lin; reduction of nitrate; and susceptibility to epidermidis was found to be resistant to all anti- novobiocin. The manufacturer’s recom- biotics. Teicoplanin resistance determined by agar disc di usion was confirmed by the agar mended procedures were followed. Strain pro- V dilution method (MIC 32 µg/ml). files were read and identified with automatic testing bacteriology equipment and were inter- preted with APILAB software. Discussion Antibiotic susceptibility tests were deter- Methods for the identification of CoNS mined by agar disc diVusion (Kirby–Bauer include conventional as well as commercial 10 method). The following antibiotics were systems. The conventional method8 is relatively http://bjo.bmj.com/ tested: penicillin, gentamicin, tetracycline, cumbersome for routine laboratory use and erythromycin, ciprofloxacin, and teicoplanin. A may take up to 5 days of incubation to obtain a standard agar dilution method11 was used to result. Commercial biochemical systems can confirm teicoplanin resistance determined by identify a number of CoNS with accuracy of agar disc diVusion. In brief, overnight cultures more than 95% with relative speed and of bacteria (≥109 colony forming units/ml) simplicity.13 In this study, species identification were plated at a series of dilutions on tryptic of CoNS was performed by using API ID 32 soy agar plates containing antibiotic-free me- Staph, a commercially available biochemical on October 3, 2021 by guest. Protected copyright. dium or twofold dilutions of teicoplanin within test system which can identify 24 species. This the drug concentration range of 0.1–128 system has been reported to be able to provide µg/ml. Plates were incubated at 37°C for 48 a correct species identification for 95.2% of hours and the number of bacterial colonies was CoNS analysed, with an accuracy of 98%– counted. Teicoplanin minimal inhibitory con-
Load more

Recommended publications
  • BD™ Baird-Parker Agar
    INSTRUCTIONS FOR USE – READY-TO-USE PLATED MEDIA PA-255084.04 Rev.: Sep 2011 BD Baird-Parker Agar INTENDED USE BD Baird-Parker Agar is a moderately selective and differential medium for the isolation and enumeration of Staphylococcus aureus in foods, environmental, and clinical specimens. PRINCIPLES AND EXPLANATION OF THE PROCEDURE Microbiological method. A variety of media is used for the isolation of Staphylococcus aureus, which plays a major role in food-poisoning and in human clinical infections. The formulation of the present Baird-Parker Agar was published in 1962.1 It is a partially selective medium which applies the ability of staphylococci to reduce tellurite to tellurium and to detect lecithinase from egg lecithin. Baird- Parker Agar is widely used and is included in many standard procedures for testing foods, cosmetics, or swimming pool waters for the presence of Staphylococcus aureus.2-6 It may also be used for the isolation of S. aureus from clinical specimens and is also called Egg- Tellurite-Glycine-Pyruvate Agar (ETGPA).7,8 BD Baird-Parker Agar contains the carbon and nitrogen sources necessary for growth. Glycine, lithium chloride and potassium tellurite act as selective agents. Egg yolk is the substrate to detect lecithinase production, and, in addition, lipase activity. Staphylococci produce dark gray to black colonies due to tellurite reduction; staphylococci that produce lecithinase break down the egg yolk and cause clear zones around respective colonies. An opaque zone of precipitation may form due to lipase activity. The medium must not be used for the isolation of staphylococci other than S. aureus.
    [Show full text]
  • Update on Coagulase-Negative Staphylococci—What the Clinician Should Know
    microorganisms Review Update on Coagulase-Negative Staphylococci—What the Clinician Should Know Ricarda Michels †, Katharina Last † , Sören L. Becker and Cihan Papan * Institute of Medical Microbiology and Hygiene, Saarland University, 66424 Homburg, Germany; [email protected] (R.M.); [email protected] (K.L.); [email protected] (S.L.B.) * Correspondence: [email protected]; Tel.: +49-6841-16-23943 † These authors contributed equally to this work. Abstract: Coagulase-negative staphylococci (CoNS) are among the most frequently recovered bacteria in routine clinical care. Their incidence has steadily increased over the past decades in parallel to the advancement in medicine, especially in regard to the utilization of foreign body devices. Many new species have been described within the past years, while clinical information to most of those species is still sparse. In addition, interspecies differences that render some species more virulent than others have to be taken into account. The distinct populations in which CoNS infections play a prominent role are preterm neonates, patients with implanted medical devices, immunodeficient patients, and those with other relevant comorbidities. Due to the property of CoNS to colonize the human skin, contamination of blood cultures or other samples occurs frequently. Hence, the main diagnostic hurdle is to correctly identify the cases in which CoNS are causative agents rather than contaminants. However, neither phenotypic nor genetic tools have been able to provide a satisfying solution to this problem. Another dilemma of CoNS in clinical practice pertains to their extensive Citation: Michels, R.; Last, K.; Becker, antimicrobial resistance profile, especially in healthcare settings. Therefore, true infections caused by S.L.; Papan, C.
    [Show full text]
  • 74226 Coagulase Test (Tubes)
    74226 Coagulase Test (Tubes) For the detection of coagulase-negative or -positive organisms (Staphylococcus aureus). Product Description: 1 box contains 6 vials (each with 3 ml lyophilized rabbit plasma with EDTA) Store below 8°C and use before expiry date. The rehydrated plasma is stable for 30 days at – 20°C. Directions: a) Conduct the coagulase test on 5 typical and/or 5 atypical colonies on Baird-Paker Agar (Cat. No. 11705) or 5 suspect colonies from other culture media (Staphylococcus Agar, Cat. No. 70193, Blood Agar (Base), Cat. No. 70133, Vogel Johnson Agar, Cat. No. 70195). b) Transfer each of the selected colonies with a sterile inoculation loop to separate culture tubes containing Brain Heart Broth (Cat. No. 53286) and incubate at 37°C for 20-24 hours. c) Rehydrate the lyophilized rabbit plasma with EDTA in 3 ml of distilled water. d) Pipette 0.3 ml of the rabbit plasma into a sterile culture tube using a sterile pipette. e) Carefully mix 0.1 ml of the Brain Heart Broth culture or 1/2 an inoculation loop of colony material from Baird-Paker, Staphylococcus or Blood Agar with the plasma in the sterile culture tube and incubate at 37°C. (Material from Vogel Johnson or Mannitol Salt Phenol Red Agar is not suitable for the test. A Brain Heart Broth culture is favored.) f) Check the tubes every hour for coagulation by gently tipping to the side (do not shake). g) The coagulase test is positive if more than 75% of the tube contents has formed a coherent clot.
    [Show full text]
  • Diagnosis and Microecological Characteristics of Aerobic Vaginitis in Outpatients Based on Preformed Enzymes
    Taiwanese Journal of Obstetrics & Gynecology 55 (2016) 40e44 Contents lists available at ScienceDirect Taiwanese Journal of Obstetrics & Gynecology journal homepage: www.tjog-online.com Original Article Diagnosis and microecological characteristics of aerobic vaginitis in outpatients based on preformed enzymes * Zhi-liang Wang a, Lan-yong Fu b, Zheng-ai Xiong a, , Qin Qin a, Teng-hua Yu c, Yu-tong Wu a, Yuan-yuan Hua a, Yong-hong Zhang a a Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China b Department of Obstetrics and Gynecology, Ningde Hospital, Fujian Medical University, Dongqiao District, Ningde City, China c Department of Endocrine and Breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China article info abstract Article history: Objective: Aerobic vaginitis (AV) is a recently proposed term for genital tract infection in women. The Accepted 3 June 2015 diagnosis of AV is mainly based on descriptive diagnostic criteria proposed by Donders and co-workers. The objective of this study is to report AV prevalence in southwest China using an objective assay kit Keywords: based on preformed enzymes and also to determine its characteristics. aerobic vaginitis Materials and methods: A total of 1948 outpatients were enrolled and tested by a commercial diagnostic genital tract infections kit to investigate the AV prevalence and characteristics in southwestern China. The study mainly mixed infection examined the vaginal ecosystem, age distribution, Lactobacillus amount, and changes in pH. Differences vaginal microecological within groups were analyzed by Wilcoxon two-sample test. Results: The AV detection rate is 15.40%. The AV patients were usually seen in the sexually active age group of 20e30 years, followed by those in the age group of 30e40 years.
    [Show full text]
  • Department of Microbiology Quality Manual Policy # MI GEN Page 1 of 36 Version: 1.5 CURRENT Section: Bacteriology Procedures Su
    Policy # MI_GEN Page 1 of 36 Department of Microbiology Quality Manual Version: 1.5 CURRENT Section: Bacteriology Procedures Subject Title: Genital Tract Culture Manual Prepared by QA Committee Issued by: Laboratory Manager Revision Date: 7/14/2021 Approved by Laboratory Director: Next Review Date: 7/14/2023 Microbiologist-in-Chief Uncontrolled When Printed TABLE OF CONTENTS INTRODUCTION ............................................................................................................................... 2 LOWER GENITAL TRACT ............................................................................................................ 4 CERVICAL (ENDOCERVICAL) SWAB .............................................................................. 4 GROUP B STREPTOCOCCUS SCREEN ............................................................................. 7 VAGINITIS SCREEN ............................................................................................................ 10 VAGINAL CULTURE ........................................................................................................... 14 URETHRAL SWAB .............................................................................................................. 18 PENIS SWAB ......................................................................................................................... 20 SEMINAL FLUID .................................................................................................................. 23 UPPER GENITAL TRACT CULTURE .......................................................................................
    [Show full text]
  • Staphylococci
    STAPHYLOCOCCI Staphylococci are typical Gram-positive bacteria forming irregular clusters of cocci. Staphylococci are widespread in nature, although they are mainly found on the skin, skin glands and mucous membranes of mammals and birds, but can cause infection under certain circumstances. 1S. aureus is more pathogenic than the other common members of the genus, S. epidermidis and S. saprophyticus. S. epidermidis has been known to cause various hospital-acquired infections (such as prosthetic or indwelling devices), whereas S. saprophyticus is mainly associated with urinary tract infections in young females who are sexually active. Disease processes with S. aureus are numerous. The portal of entry is variable, since they gain access to the body via the skin, the respiratory tract or the genito- urinary tract. Staphylococcus aureus expresses many potential virulence factors: 1. surface proteins - promote colonization of host tissues 2. leukocidin, kinases, hyaluronidase - invasins that promote bacterial spread in tissues 3. capsule, Protein A - surface factors that inhibit phagocytic engulfment 4. carotenoids, catalase - enhance staphylococcal survival in phagocytes 5. protein A, coagulase - immunological disguises 6. hemolysins, leukotoxin, leukocidin - membrane-damaging toxins that lyse eucaryotic cell membranes 7. 2TSST, 3ET - exotoxins that damage host tissues or otherwise provoke symptoms of disease 8. inherent and acquired resistance to antimicrobial agents. Fig. 1 Virulence determinants of Staphylococcus aureus. 1 S. - Staphylococcus 2 TSST - Toxic Shock Syndrome Toxin 3 ET - Exfoliatin Toxin Staphylococci can cause many forms of infection: 1. S. aureus causes superficial skin lesions (boils) and localized abscesses in other sites. 2. S. aureus causes deep-seated infections, such as osteomyelitis and endocarditis and more serious skin infections (furunculosis).
    [Show full text]
  • Coagulase Activity: Plasma Suitability and Anticoagulants Tech Com: Microbiology
    Coagulase Activity: Plasma Suitability and Anticoagulants Tech Com: Microbiology by Cheryl V. Maloney, MT(ASCP) Downloaded from https://academic.oup.com/labmed/article/10/6/358/2640021 by guest on 25 September 2021 Pathogenic Staphylococcus aureus pro­ anticoagulant tubes were pooled respec­ duces coagulases that accelerate the tively and each mixed thoroughly. To clotting of plasmas from a number of obtain sterile guinea pig plasma, citrated animal sources. Although coagulase ac­ guinea pig whole blood (CIBCO Diag­ tivity correlates with pathogenicity, the nostics, Madison, Wl) was aseptically enzyme itself has a little known role transferred to sterile vials and cen- in the pathogenesis of staphylococcal trifuged. The sterile plasma was then infections. transferred to new sterile vials. Human serum was prepared by collecting blood Several animal plasmas including hu­ in glass tubes, letting the blood clot man plasma will serve as a satisfactory and pooling several samples. Rabbit substrate for coagulase testing.1 We in­ plasma (BBL, Cockeysville, MD) was vestigated the nature and action of coagu­ prepared according to the manufac­ lase activity by ten isolates of Staphy­ turer's instructions. lococcus aureus and tested the suitability of four human plasma pools and rabbit To test the sterility of each plasma plasma as substrates. Since guinea pig pool, aliquots were cultured in brain plasma is not suitable for coagulase heart infusion broth (BBL) and observed 2 testing, we studied guinea pig plasma for growth after 24 hours of incubation. to determine if there is a deficiency of coagulase reacting factor (CRF) or if an The tube method of Lenette, Spauld- 3 inhibitor is present.
    [Show full text]
  • Development of a Semi-Synthetic Medium Supporting Adherent Growth in Coagulase-Negative Staphylococci
    Portland State University PDXScholar Dissertations and Theses Dissertations and Theses 1-1-1992 Development of a Semi-synthetic Medium Supporting Adherent Growth in Coagulase-Negative Staphylococci Abbas Sadeghi Portland State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/open_access_etds Let us know how access to this document benefits ou.y Recommended Citation Sadeghi, Abbas, "Development of a Semi-synthetic Medium Supporting Adherent Growth in Coagulase- Negative Staphylococci" (1992). Dissertations and Theses. Paper 13. https://doi.org/10.15760/etd.13 This Thesis is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. AN ABSTRACT OF THE THESIS OF Abbas Sadeghi for the Master of Science in Biology presented August 3, 1992. Title: Development of a Semi-synthetic Medium Supporting Adherent Growth in Coagulase-negative staphylococci. APPROVED BY TilE MEMBERS OF TilE THESIS COMMITTEE: Mary. L./Taylor, Ohair Richard Peterson Gordo~ , Kilg:"~~r - A semi-synthetic medium for use in determining adherent growth with Staphylococcus epidermidis and Staphylococcus saprophyticus was developed. Production of an adherent biofilm was dependent upon the presence of hematin in the growth medium. Clinical strains of Staphylococcus epidermidis were tested for production of an adherent biofilm in trypticase soy broth, the semi-synthetic medium and the hyperalimentary nutrient solution used in the neonatal hospital unit. An adherent biofilm was obtained when 2 Staphylococcus epidermidis was cultured m hematin supplemented hyperalimentary solution. Growth in the hyperalimentary nutrient solution diluted with fetal calf serum showed the same growth rate as when the nutrient solution was diluted with water.
    [Show full text]
  • Evidence-Based Treatments of Based Treatments of Urinary Tract
    2/9/2015 EvidenceEvidence--BasedBased Treatments of Urinary Tract Infections David R. Ellington, MD, FACOG Assistant Professor Division of Urogynecology and Pelvic Reconstructive Surgery Disclosures No Relevant Disclosures Case Study 26 year old G0P0 woman calls your office to report: 3 days of progressive urinary urgency and dysuria She denies fevers, chills, low back pain, or vaginal discharge Two months ago you treated her with a 33--dayday course of Macrobid for presumptive urinary tract infection (UTI), and her symptoms resoldldlved She is otherwise healthy, but this episode would make her 4thth in the past 12 months.. 1 2/9/2015 Objectives Participant will be able to: Describe pertinent history in the evaluation of UTIs Describe the pathophysiology of UTIs Describe diagnostic methods and criteria of various types of UTIsof UTIs Describe techniques, accuracy, sensitivity, and specificity of: dipstick urinalysis, microscopic urinalysis, and urine cultureculture Describe indications for upper tract imaging/cystoscopy Describe evidence for various treatment options Definitions BacteriuriaBacteriuria:: presence of bacteria in urine infection, colonization, contamination Pyyyuria: presence of WBC in urine inflammatory response of urothelium UTI: inflammatory response of the urothelium to bacterial invasion associated with bacteriuria and pyuria Bacteriuria UTI Pyuria/ Inflammation 2 2/9/2015 What if both are NOT present? Bacteriuria without pyuria Colonization Contamination Pyuria without bacteriuria Bladder
    [Show full text]
  • Bacteria Chart1
    SPECIES MORPHOLOGY GRAM O2 REQ. DIAGNOSTIC TEST STUFF TO KNOW Staphylococcus clusters of cocci positive facultative coagulase positive Virulence: -Protein A binds Fc of IgG - protects from phagocytosis aureus anaerobe catalase positive -fibrinogen/collagen binding proteins promote adhesion to host tissues -nonsporulating stains gold on sheep -coagulase leads to fibrin deposition around bacteria, protects from phagocytosis -nonmotile blood agar -hemolysins (α,β,γ,δ) destroy RBCs, PMNs, macrophages and platelets -leukocidin destroys WBCs -alpha toxin may mediate sepsis -penicillinase (β-lactamase) inactivates penicillin's β-lactam structure -penicillin binding protein can be resistant to penicillin -hyaluronidase, staphylokinase, lipase, protease break down host tissues Diseases: toxin-mediated 1. Toxic shock by producing TSST-1; myalgias, fever, chills, Tx: methicillin hypotension, rash (oxacillin, nafcillin) 2. Exfoliatin toxin produces "scalded skin syndrome" - skin sloughing MRSA: vancomycin, 3. Enterotoxins (heat stable) cause gastroenteritis (food poisoning) linezolid, direct invasion streptogramins Pneumonia, meningitis, skin infections, endocarditis, sepsis, UTI, osteomyelitis, nosocomial endocarditis, IV user endocarditis Staphylococcus clusters of cocci positive facultative coagulase negative commensal in nasopharynx in ~30% of population, also on skin epidermidis anaerobe catalase positive elaborate extracellular polysaccharide capsule = biofilm (slime) -nonsporulating highly resistant to antibiotics! -nonmotile Diseases: nosocomial
    [Show full text]
  • Management of Vaginal Discharge
    VAGINAL DISCHARGE MANAGEMENT OF VAGINAL DISCHARGE Vaginal discharge may be entirely normal, or a sign of infection. In either case, it is a relatively common presentation in general practice and deserves some attention. The normal anatomy, physiology and microbial ecology of the vagina are age- dependent as are the sources of vaginal infections. In the neonatal period, the vagina is influenced by maternal oestrogen and has a stratified squamous epithe- lium. Later, and until puberty, the vagina is lined by cuboidal cells and the pH is around 7.0. Following puberty, oestrogen causes a change to stratified squa- mous epithelium. The predominant microbial flora at this age are lactobacilli such as L. crispatus and L. jensenii, which produce lactic acid, and the pH falls to 4.0 - 4.5. The other vaginal flora include diphtheroids, β-haemolytic strepto- cocci, coliforms and coagulase-negative staphylococci.1 VAGINAL DISCHARGE IN PRE-PUBERTAL GIRLS Vaginal symptoms including a discharge in pre-pubertal girls ought to be investi- A A HOOSEN gated microbiologically as the sexually transmitted (ST) pathogens Neisseria gon- 2 MSc, MB ChB, MMed, FCPath orrhoeae and Chlamydia trachomatis may be isolated. Chief Specialist and Head Other non-ST pathogens include β-haemolytic streptococci Group A (S. pyo- Department of Microbiological Pathology genes), Shigella flexneri and Enterobius vermicularis. MEDUNSA Professor Anwar Hoosen is currently Head of VAGINAL DISCHARGES IN POST-PUBERTAL WOMEN the NHLS’s Microbiology Laboratory for the Vaginal infection is one of the top 25 reasons for women to consult doctors in the Northern Branch. He has conducted numerous USA.
    [Show full text]
  • Distinguishing True Coagulase-Negative Staphylococcus Infections from Contaminants in the Neonatal Intensive Care Unit
    Journal of Perinatology (2013) 33,52–58 r 2013 Nature America, Inc. All rights reserved. 0743-8346/13 www.nature.com/jp ORIGINAL ARTICLE Distinguishing true coagulase-negative Staphylococcus infections from contaminants in the neonatal intensive care unit CM Healy1,2, CJ Baker1,2,3, DL Palazzi1,2, JR Campbell1,2 and MS Edwards1,2 1Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; 2Woman’s Hospital of Texas, Houston, TX, USA and 3Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA can rapidly progress and even be fatal before the infecting Objective: To characterize true coagulase-negative Staphylococcus (CoNS) pathogen has been identified.3,4,8,9 infections in infants receiving neonatal intensive care. Coagulase-negative staphylococci (CoNS) are commensal skin Study Design: Retrospective cohort study of neonatal intensive care unit flora but these organisms account for up to one-half of reported (NICU) infants with clinical sepsis and CoNS isolated from X2 blood bloodstream infections in very low birth weight (<1500 g) 3,4,7–9,11 cultures (BCs) or one BC and a sterile site (proved infection) or CoNS infants. CoNS present a particular dilemma because their isolated from one BC and deemed significant after blinded data review isolation from a single blood culture (BC) in an NICU patient can (probable infection). reflect contamination rather than true bacteremia. The difficulty inherent in distinguishing true infections from culture Result: In all, 98% of 40 proved and 96% of 55 probable infections contaminants potentially results in over-representation of CoNS in occurred in infants with birth weight (BW) <2000 g and gestation <34 NICU sepsis incidence data, despite attempts to define infection weeks.
    [Show full text]