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180 Cards in this Set
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Healthcare-associated infections |
a local or systemic infection acquired at a healthcare facility aka nosocomical infection some acquired from patients, some hospital personnel |
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direct detection of pathogens |
some pathogens can be readily identified by microscopic examination of tissue samples ex: Neisseria Gonorrhoeae |
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minimum inhibitory concentration (MIC) |
procedure for antibiotic susceptibility testing employs an antibiotic dilution assay wells containing serial dilutions of antibiotics are inoculated with a standard amount of a test organism look for inhibited growth |
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disc diffusion test |
standard procedure for assessing antimicrobial activity agar media is spread evenly with culture of bacteria where the antibiotic is, microbes should die |
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inhibition zones |
used to determine an organisms susceptibility to an antimicrobial agent |
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e-test |
a non-diffusion based technique that employs a performed and predefined gradient of an antimicrobial agent immobilized on a plastic strip |
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how do clinicians often identify an infection? |
measure the patients antibody titer (quantity) against antigens produced by the pathogenq |
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what tests do clinicians use to identify an infection? |
agglutination and EIA skin testing too |
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serology |
the study of antigen-antibody reactions in vitro |
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specificity |
ability of an antibody preparation to recognize a single antigen |
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sensitivity |
defines the lowest amount of an antigen that can be detected |
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agglutination |
the visible clumping of a particulate antigen when mixed with antibodies specific for the particulate antigens simple to perform, specific, inexpensive, rapid and sensitive standardized tests are used to identify blood group antigens and many pathogens and pathogen products |
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direct aggluatnation |
result when soluble antibody causes clumping due to interaction with antigen that is an integral part of the surface of the cell or other insoluble particle used for the classification of antigens found on the surface of red blood cells |
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passive agglutination |
the agglutination of soluble antigens or antibodies that have been absorbed or chemical coupled to cells of insoluble particles (ex: latex beads, charcoal) reactions can be up to 5 times more sensitive than direct tests |
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enzyme immunoassay (EIA) or enzyme linked immunosorbent assay (ELISA) |
very sensitive immunological assay widely used in clinical diagnostic and research applications EIAs employ covalently bonded enzymes attached to antibody molecules rapid tests are similar to EIAs both allow detection of antigen-antibody complexes |
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four different EIA methodologies |
direct, indirect, sandwich, combination |
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direct EIA |
detection of antigen |
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indirect EIA |
detection of antibody |
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sandwich EIA |
detection of antibody |
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combination EIA |
combo of direct EIA and sandwich EIA |
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rapid tests |
reagent are absorbed to support material bodily fluid is applied to support matrix color forms when concentration of chromophore gets high enough |
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rapid text matrix |
contains soluble antigen conjugated to a color molecule (chromophore) also contains a line of fixed antigens antibodies bind to antigens |
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chromophore |
colored molecule conjugated to a soluble antigen |
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immunoblot (western blot) |
electrophoresis of proteins, followed by a transfer to a membrane and detection by addition of specific antibodies detects antibodies to specific antigens or the antigens themselves |
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polymerase chain reaction (PCR) |
presence of amplified gene segment confirms presence of pathogen reverse transcriptase PCR, quantitative real-time PCR |
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reverse transcriptase PCR (RT-PCR) |
uses pathogen specific RNA to make cDNA |
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quantitative real-time PCR (qPCR) |
uses fluorescently labeled PCR products almost immediate results |
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mannitol salt media |
selective for staphylococci differential mannitol fermenters yellow (acidification) |
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MacConkey |
selective for gram positive differential for lactose fermentation |
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blood |
selective for gram positive cocci differential for streptococci based on hemolysis |
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eosin-methylene blue |
selective for gram negative differential for lactose or sucrose fermentation |
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immunotherapy |
aka biologic therapy type of cancer treatment designed to boost body's natural defenses to fight cancer uses substances either made by the body or in a lab to improve/restore immune system function |
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emerging antibiotic threats |
in US, 2 million infection/year 23,000 ppl die from these infections clostridium difficile poor prescribing practices by physicians. half of all antibiotic prescriptions do not meet current guidelines for antibiotic use |
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clostridium difficile |
a hospital acquired infection that is often caused by antibiotic use, 250,000 americans/year |
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colistin |
polypeptide antibiotic makes holes in bacterial membrane isolated in 1950's not used much due to human nephrotoxicity |
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polymyxin antibiotics |
mechanisms of action: target: bacterial cell membrane binding with bacterial membrane occurs through electrostatic interactions between cationic polypeptide (colistin) and anionic lipopolysaccharide (LPS) molecules in outer membrane of gram negative bacteria leads to a derangement of the cell membrane the result of this is an increase in permissibility of cell envelope, leakage of cell contents, and subsequent cell death |
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antimicrobial drugs are classified on basis of: |
molecular structure, mechanisms of action, spectrum of antimicrobial activity |
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sulfa drugs: |
discovered by Gerhard Domagk in the 1930's inhibit the growth of bacteria (sulfanilamide is the simplest) high therapeutic index folate/prenatal vitamins |
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isoniazid |
a growth analog effective only against mycobacterium interferers with synthesis of mycolic acid |
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quinolones |
antibacterial compounds that interfere with DNA gyrase (ciprofloxacin) |
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antibiotics |
naturally produced antimicrobial agents fewer than 1% known antibiotics are clinically useful can be modified to enhance efficacy (semisynthetic) |
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semisynthetic |
the ability of modifying an antibiotic to enhance its efficacy |
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broad spectrum antibiotics |
effective against both positive and negative gram bacteria |
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b-lactam |
antibiotics are one of the most important groups of antibiotics of all time include penicillins and cephlosporins over half of all antibiotics used worldwide |
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penicillins |
disovered by alexander fleming effective primarily against gram positive bacteria some synthetic forms are effective against some gram negative bacteria target cell wall synthesis |
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cephalosporins |
produced by fungus cephalosporium same mode of action as the penicillins broader spectrum of activity than penicillins resistant to enzymes that destroy b-lactam ring commonly used to treat gonorrhea |
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aminoglycosides |
antibiotics that contain amino sugars bonded by glycosidic linkage ex: kanamycin, neomycin, amikacin not commonly used today used when others fail |
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antiviral drugs |
target host structures resulting in toxicity most successful and commonly used antivirals are the nucleoside analogs (AZT) nonnucleoside reverse transcriptase inhibitors (NNRTI) |
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AZT |
block reverse transcriptase and production of viral DNA aka nucleoside reverse transcriptase inhibitors |
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nonnucleoside reverse transcriptase inhibitors (NNRTI) |
bind directly to RT and inhibit reverse transcription |
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protease inhibitors |
inhibit the processing of large viral proteins into individual components |
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fusion inhibitors |
prevent viruses from successfully fusing with the host cell |
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interferons |
small proteins that prevent viral multiplication by stimulating antiviral proteins in uninfected cells |
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neuraminidase inhbitiors (Tamiflu, relenza) |
successfully limits influenza infection |
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antimicrobial drug resistance |
the acquired ability of a microorganism to resist the effects of a chemotheraputic agent to which it is normally sensitive |
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5 reasons that microogranisms are naturally resistant to certain antibiotics |
organism is impermeable to antibiotic organism can inactivate the antibiotic organism may modify the target of the antibiotiv organisms may develop a resistant biochemical pathway organisms may be able to pump out all the antibiotic (efflux) |
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r plasmid |
most drug resistant bacteria isolated from patients contains drug resistant genes located here. evidence that they predate the antibiotic era use of antibiotics in medicine, vet medicine and agriculture selects for the spread of them |
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epidemiology |
the study of the occurrence, distribution, and determinants of health and disease in a population |
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epidemic |
when a disease occurs in a large number of people in a population at the same time |
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pandemic |
widespread, usually worldwide |
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endemic |
constantly present disease in a population, usually low incidences |
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incidence |
the number of new cases of the disease in a given period of time |
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prevalence |
total number of new and existing cases in a population in a given time |
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outbreak |
occurs when a number of cases of a disease are reported in a short period of time |
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subclinical infections |
diseased individuals who show no/mild symptoms |
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mortality |
the incidence of death in a population |
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morbidity |
the incidence of disease, including fatal and nonfatal |
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disease progression |
infection, incubation period, acute period, decline period, convalescent period |
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infection |
the organism invades and colonizes host |
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incubation period |
the time between infection and onset of symptoms |
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acute period |
disease is at its height |
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decline period |
disease symptoms are subsiding |
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convalenscent period |
patient regains strength and returns to normal |
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herd immunity |
resistance of a group to infection due to immunity of a high portion of the group |
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direct host to host transmission |
infected individual transmits a disease directly to a susceptible host without the assistance of an intermediary (Ex: flu, common cold, STD, ringworm) |
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indirect host to host transmission |
occurs when transmission is facilitated by a living or nonliving agent |
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living agent |
vector |
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non living agent |
formites |
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common source epidemics |
usually arises from contamination of water/food (ex: cholera) |
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host to host epidemics |
the disease shows a slow, progressive rise and a gradual decline (ex: influenza and chicken pox) |
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reservoirs |
sites in which infections agents remain viable and from which individuals can become infected |
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zoonosis |
any disease that primarily infects animals but it occasionally transmitted to humans control may not eliminate the disease a a potential public health problem
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carriers |
pathogen infected individuals showing no signs of clinical disease potential sources of infection may be individuals in the incubation period of the disease or asymptomatic can be identified using diagnostic techniques, including culture and immunoassays typhoid mary is an example of a carrier |
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control directed against the reservoir |
if its an animal, can be immunized or destroyed when humans are the reservoir, eradication can be difficult those w disease can be quarantined, immunized and treated used by the WHO to eradicate small pox |
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immunization |
diseases have been controlled using immunization ex: small pox, rubella, tetanus |
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quarantine |
restricts the movement of an individual with an active infection |
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controls against transmission of pathogen |
surveillance, pathigen eradication |
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surveilance |
the observation, recognition, and reporting of diseases |
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pathogen eradication |
goal is to temove all of a pathogen from any reservoir (smallbox, polio, potentially rabies, leprosy and others) |
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emerging factors of infectious disease |
human demographics and behavior, technology and industry, economic development and land use, internaltional travel and change, breakdown of public health measures, abnormal natural occurances |
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tuberculosis |
worldwide infectious disease of humans incidence is increasing transmitted by airborne droplets cell mediated immunity plays a critical role in the prevention of active disease after infection classified as a primary infection or postprimary infection |
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initial |
primary infection |
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reinfection |
postprimary infection |
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primary infection with tb |
hypersensitizes the patient to the bacteria and alters the individuals response to subsequent exposure hypersensitivity measured by diagnostic skin test |
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postprimary infection |
chronic tb often results in the gradual spread of tubercular lesions in the LUNGS |
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spread of tb prevented by |
hospitalization of patients in negative pressure rooms use of face masks for healthcare workers |
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treatment for tb |
antimicrobial therapy isoniazid: growth fator analog nicotinamide treatment usually requires a 9 month regime affects the synthesis of mycolic acid and mycobacteria |
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hansen's disease (leprosy) |
m. leprae is the causative agent armadillo is the only experimental animal that has been successfully use to grow most serious form is characterized by folded, bulblike lesions on the body |
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pathogenicity of m leprae |
due to a combination of delayed hypersensitivity and the invasiveness of the organism tramission is by both direct contact and respiratory routes incubation times vary from severl weeks to years the incidence of leprosy worldwide is low |
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meningitis |
inflammation of the meninges membranes that line the central nervous system, especially the spinal cord and brain can be viral, bacterial, fungal, or protist infection |
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neisseria meningitides |
normal part of microbiome gram negative, nonsporulating, obligately aerobic, oxidase-positive encapsulated dipolococcus causes one type of infectious bacterial meningitis and a related infection, meningococcemia 13 pathogenic strains are recognized based on antigenic differences in their capsular polysaccarides |
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Meningococcal meningitis |
Often? (can 95% don’t )occurs in epidemics, usually in closed populations Typically affects older school-age children and young adults - Transmission is typically via airborne routes -Treatment is usually penicillin G -Incidence has decreased in recenty ears due to widespreadvaccination in susceptible populations – Meningococcemia blood infection without Brain/CNSinvolvement |
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most prevalent human infections are causedby |
viruses |
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most viral diseases |
are acute, self limiting infections |
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viruses are ______ easily controlled by chemotheraputic methods |
less |
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few serious viruses have been effectively controlled by vaccination |
small pox and rabies |
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measles (rubeola or 7-day measles) |
often affects suseptible children as an acute, highly infectious, often epidemic disease caused by paramyxovirus virus enters the nose and throat by airbourne transmission used to be common childhood illness now only occurs in rather isolated outbreaks due to widespread immunizatin programs 2014 outbreak imported and unvaccinated |
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paramyxovirus |
negative strand RNA virus |
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mumps |
Caused by a paramyxovirus (like measles) Highly infectious Spread by airborne droplets Characterized by inflammation of the salivaryglands |
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Rubella (German measles or 3-day measles) |
Caused by a positive-strand RNA virus of the togavirus group Disease symptoms resemble measles but aregenerally milder and less contagious Routine childhood immunization is practiced inthe U.S. MMR |
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Chickenpox(varicella) |
F16310CH29P2PII Common childhood disease characterized by a systemic papular rash Caused by varicella-zoster virus (VZV), aherpesvirus VZV is highly contagious and transmitted byinfectious droplets A vaccine is presently used in the U.S. VZV virus establishes a lifelong latent infection innerve cells The virus occasionally migrates to the skin surface,causing a painful skin eruption (shingles) |
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colds |
The most common of infectious diseases – Viral infections transmitted via airbornedroplets – Infections are usually of short duration – Symptoms milder than other respiratorydiseases – Symptoms include rhinitis, nasal obstruction,watery nasal discharges, and malaise |
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The Common Cold |
– Commonly caused by rhinoviruses • Positive-sense, single-stranded RNA viruses • Nearly 115 different strains identified – Approximately 15% of colds are due tocoronaviruses – Approximately 10% of colds are due to otherviruses |
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most antiviral drugs are ineffective against the common cold, but _______ ________ and ______ _______ blocking drugs have shown promise |
pyrazidine derivatives and rhinovirus receptor |
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influenza |
-Influenza is caused by an RNA virus of theorthomyxovirus group There are three different types ofi nfluenzaviruses (A, B, C) -Influenza A is the most important human pathogen -outbreaks occur annually due to the plasticity of theinfluenza genome |
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Antigenic shift |
Major change in influenza virus antigen due to gene reassortment |
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antigenic drift |
Minor change in influenza virus antigens due to genemutation |
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prevention of influenza |
immunization, careful worldwide surveilance |
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treatment of influenza |
– Use of various drugs – Most effective when administered early – Aspirin should be avoided (anti coagulant anti platelet) – Reyes Syndrome - no know cause |
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Airborne Pathogens |
Aerosols are important for person-to-persontransmission of many infectious diseases Most pathogens survive poorly in air, thus, areeffectively transmitted only over short distances |
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Respiratory infections |
– Different pathogens characteristically colonize the respiratory tract at different levels – The upper and lower respiratory tracts offerdifferent environments and favor differentmicrobes |
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upper respiratory tract |
Staphylococcus aureus, Neisseria meningitidis, Streptococcus pyrogenes, Corynebacterium diphtheriae, Haemophilus influenzae |
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lower respiratory tract |
Influenza virus, Coccidioides immitis, Bordetella pertussis, Streptococcus pneumoniae, Coxiella burnetii, Chlamydophila psittaci |
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Streptococcus pyogenes (group A Streptococcus;GAS) |
– Commonly found in low numbers in the upperrespiratory tract of healthy individuals – Causative agent of “strep throat” – Can also cause infections of the inner ear,mammary glands, and skin - Infections occur if host defenses are weakened ora new, highly virulent strain is introduced |
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Streptococcal Diseases |
– Certain GAS strains carry a lysogenicbacteriophage that encodes exotoxins responsiblefor symptoms of toxic shock syndrome and scarletfever – Untreated or insufficiently treated infections canlead to other diseases |
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rheumatic fever |
autoimmunity due to molecularmimicry, anti bacterial antibodies cross react withheart |
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Definitive diagnosis of streptococcusstrains is by |
culture Beta Hemolysis |
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Diphtheria |
– A severe respiratory disease that typically infects children – Caused by Corynebacterium diphtheriae (Fi• A bacterium that forms irregular rods during growth bowling pin – Preventable and treatable |
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Corynebacterium diphtheriae |
– Spreads by airborne droplets and enters the body via the respiratory route – Previous infection or immunization provides resistance – Pathogenic strains lysogenized by bacteriophage produce apowerful exotoxin that causes Tissue death The appearance of the pseudomembrane in the patient’s throat |
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Diagnosis of Diphtheria |
must be isolated from the throat |
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prevention diptheria |
vaccine |
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treatment diptheria |
– Antibiotics – Diphtheria antitoxin* available for acute cases • Early administration necessary • antibodies* |
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Pertussis (whooping cough) |
– An acute, highly infectious respiratory disease – Caused by infection with Bordetella pertussis – Observed frequently in school-age children – Characterized by a recurrent, violent cough – There has been a consistent upward trend ofinfections since the 1980s – Inadequately immunized children, adolescents,and adults are at high risk for acquiring andspreading pertussis |
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Diagnosis pertussis |
– Made by fluorescent antibody staining of a nasopharyngeal swab specimen – Also made by actual culture of the organism |
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Prevention |
vaccination soon after birth |
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treatment |
antibiotics, elimination is helped by the immune response |
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Staphylococcus |
-a nonsporulating, gram-positive cocci that divides into several planes to form irregular clumps -cause diseases including acne,boils,pimples,impetigo, pneumonia, osteomyelitis, carditis, meningitis, and arthritis - Many diseases result from pyogenic(pus) infection or from theactions of staphylococcal superantigen exotoxins |
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pus formation |
Leukocidin andenzymes lead to |
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fibrin formation |
Coagulase fibrin wallsoff infection |
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Helicobacter pylori |
– A gram-negative, highly motile, spiral-shapedbacterium Associated with gastritis, ulcers, andgastric cancers – Colonizes the non-acid-secreting mucosa of thestomach and upper intestinal tract – Transmitted via person-to-person contact oringestion of contaminated food or water – Aussie DR Koch’s postulate experiment |
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H. Pylori: stomach symbiont |
-Flagellated, helical - Senses ph, produces Urease, increases acid? -50% world colonized, 85% asymptomatic - 80% of gastric, 90% of duodenal ulcers H pylori related - Grehlin – “hungry” expression stops when stomach stretchedLeptin satiety - Grehlin plasma levels increase in H pylori free -BUT Grehlin low in obese individuals - Eliminated in West due to antibiotics |
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Hepatitis |
– Liver inflammation caused by viruses or bacteria – Sometimes results in acute illness followed by destruction of liveranatomy and cells (cirrhosis) – A restricted group of viruses is associated with liver disease – Hepatitis viruses are diverse |
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Hepatitis A virus |
infectious hepatitis Causes mild or, rarely, severe cases of liver disease |
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Hepatitis B virus |
serum hepatitis Causes acute, often severe disease that can lead to liver failure and death |
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Hepatitis D virus |
A defective virus that cannot replicate andexpress a complete virus unless the cell is alsoinfected with hepatitis B |
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Hepatitis C virus |
Produces a mild disease initially, but mostindividuals develop chronic hepatitis that can leadto chronic liver disease |
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Hepatitis E virus |
Causes an acute, self-limiting hepatitis that varies in severity |
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Hepatitis G virus |
Causes very mild disease or is asymptomatic |
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Incidence and Prevalence of Hepatitis |
– Decreased significantly in the U.S. in the last 20 years – Viral hepatitis is still a major public healthproblem • Due to the high infectivity of the viruses and thelack of effective treatment options – Vaccines are available for Hepatitis A and Bviruses |
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AIDS |
– Recognized as a distinct disease in 1981 – Human immunodeficiency virus (HIV) is thecausative agent – Urban Myths and the Anti-hater – Accidental exposure without other riskfactors |
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HIV-1 |
the more virulent type |
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HIV-2 |
less virulent and causes a milder, AIDS-like disease |
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HIV Pathogenesis |
– HIV infects cells that contain the CD4 cell surface protein – Most commonly infected are macrophages andT-helper cells – HIV also interacts with coreceptors on target cells – RT mutation rates,The Berlin Patient HIV infection does not immediately kill the host cell Infection results in a progressive decline in CD4 cells As the number of CD4 cells declines, cytokineproduction falls, leading to reduction of the immuneresponse |
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HIV can be detected using: |
HIV-EIA,HIV-immunoblot, or rapid tests |
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problem with HIV tests |
These fail to detect infection in individuals whorecently acquired the HIV and have not made adetectable antibody window period |
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___-____ can detect HIV RNA directly from bloodand estimate the number of viruses present |
RT-PCR this is used for early detection and monitoring the progression |
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treatment HIV |
• Highly active antiretroviral therapy (HAART) • Drug combinations • Nucleoside reverse transcriptase inhibitors • Nonnucleoside reverse transcriptase inhibitors • Protease inhibitors • Fusion inhibitors PreP Pre-Exposure Prophylaxsis • Prevention as treatment |
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zoonosis |
Animal disease transmissible to humans Generally transmitted via direct contact, aerosols, or bites lyme disease, malaria, west nile |
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Rickettsias |
small bacteria that have strict intracellular existence invertebrates Associated with bloodsucking arthropods Three groups: (1) typhus group, (2) spotted fever group, and (3) ehrlichiosis group Named for Howard Ricketts Closely related to human mitochondria Contain minimal sets of genes required for intracellular dependency |
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Typhus group |
Transmitted by the body or head louse bite that gets contaminated withlouse feces 3 million deaths in WWI trench fever |
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Spotted fever group |
• Transmitted by dog and wood ticks • Over 2,000 people acquire the disease every year • Rickettsia grow in nucleus and cytoplasm• Symptoms include headache, fever, and rash |
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Ehrlichiosis group |
Emerging diseases are human granulocytic anaplasmosis (HGA) and humanmonocytic ehrlichiosis (HME), which are spread by tick bites Flu-like symptoms include fever, headache, malaise, and leukopenia orthrombocytopenia • Prompt recognition of these diseases is essential, but remains difficult • Treatment with antibiotics is usually successful • Avoiding hosts and using insect repellents are your best bets for reducingyour chances of exposure |
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Lyme disease |
• Affects humans and other animals • Old Lyme, Connecticut, was where cases were first recognized • Most prevalent tickborne disease in the U.S. • Caused by the spirochete Borrelia burgdorferi • Spread primarily by the deer tick • Powanuss virus new tick-borne -Deer and white-footed field mouse are the prime mammalian reservoirs - Also identified in Europe and Asia - In U.S., most cases reported in the Northeast and upper Midwest - Number of Lyme disease cases rising yearly |
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symptoms of lyme disease |
headache,backache,chills,andfatigue In75%of cases a large rash occurs at the site of the tick bite |
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initially can be treated with |
antibiotics |
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chronic stage develops in weeks to months |
-40–60% of these patients develop arthritis - Others develop neurological damage or heart damage - No toxins or virulence factors have been identified • Chronic Lyme’s and Powanuss virus |
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Malaria |
-A protist disease caused by Plasmodium spp. - Has a complex life cycle that includes Anopheles mosquitoes as vectors - Estimates of 350,000,000 people infected worldwide - Each year over 1,000,000 people die from malaria - Generally found in tropical and subtropical regions • 3.5 B at risk • 200M cases 400K deaths • Preventive measures account forreduction |
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diagnosis of malaria |
requires identification of Plasmodium-infected erythrocytes in blood smears |
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Some individuals in regions where malaria is endemic have sickle cell traitand other thlassemias that make them..... |
immune to malaria |
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this was a mistake |
halp |
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Humans are a dead end host for West Nile Virus. Select one:True False |
true |
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Streptococcus pneumoniae Select one: a. is surrounded by a polysaccaride capsule that makes phagocytosis very difficult. b. is the only causative agent of pneumonia. c. can only cause lung infections d. is unlikely to infect immunocompromised patients |
a |
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Which of the following is an obligate intra cellular pathogen. Select one: a. Streptococus b. Ricksettia c. plasmodium d. a, b, c |
b |
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Which of the following is/are reasons why a tick bite doesn't always lead to Lyme infection Select one: a. tick wasn't infected b. tick fed for a short time c. no bull's eye rash d. a, b, c e. a and b |
d |
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Worldwide one of the most common causes of death in HIV positive patients is TB (tuberculosis) Select one: a. True c. unknown |
a |
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Factors that have led to an increase in nosocomical, or hospital-acquired infections, include ____ Select one: a. a. lots of sick people b. b. antibiotic over use c. c invasive medical devices d. d. a, b and c |
d |
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In the DTaP vaccine, ‘a’ stands for Select one: a. a. attenuated b. b. acellular c. c. antitoxin d. d. antibody |
b |
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Reverse transcriptase is a(n )Select one: a. RNA-dependent DNA polymerase. b. DNA-dependent DNA polymerase. c. RNA-dependent RNA polymerase. d. DNA-dependent RNA polymerase. |
a |
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Extensively drug resistant Tuberculosis (XDRTB) is considered_________________. Select one: a. a. a MDRO (a multi drug resistant organism) b. b. a secondary infectionc. c. a re-emerging pathogend. d. a and c |
d |
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Lyme disease is a zoonotic disease caused by a spirochete. t/f |
true |
