MMI CTRLF Directory

Coagulase (+) = Blue Gram (+) = Purple Coagulase ( - ) = Red Gram ( - ) = Pink The CTRL -F Book of Pathogens *** Text written in this color are special mentions from the self-studies sections *** Please DO NOT USE SPELL CHECKER ON THE PATHOGEN COLUMN the suggestions are wrong for the pathogen names and if you change them it will mess up when you try to ctrl F Pathogen: Staphylococcus aureus Common Name: Cellulitis Boils Pustule Impetigo Infected abscess Impetigo is a superficial skin infection of the epidermal layer of the skin—it is usually seen in small children and is infectious from person to person. It is often seen around the mouth on the Class Morphology Symptoms Bacteria Gram + cocci in clusters Coagulase (+) - Exfoliative toxin: in scalded skin syndrome— Primary pathogen on skin destroys cell junction attachments -Some strains produce yellow colonies - Membrane-damaging toxins like leucocidin: on BAP (“yellow or golden staph”); destroys WBC many are beta-hemolytic on blood agar FIGURE - Catalase—breaks down hydrogen peroxide produced by neutrophils - DNase: breaks down DNA - TSST-1: toxic shock syndrome toxin— superantigen effects - Protein A: Fc receptor on surface of S. aureus Skin desquamation due to exfoliative toxin in toxic shock syndrome - face but can present anywhere on the skin surface Staphylococcus epidermidis Bacteria Gram + cocci in clusters Coagulase (-) From normal skin flora Staphylococcus saprophyticus Bacteria Gram + cocci in clusters Coagulase (-) Leading cause of female uti Facultative Gram + Diplococci Alpha hemolytic has capsule - can cause meningitis - needs capsule to cause disease Facultative Gram + cocci in chains Beta hemolytic Group A has capsule M protein - pyogenic (pus producing) - kinase (dissolves clots) - hemolysin (breaks down RBC) - can cause strep throat (pharyngitis) Streptococcus pneumoniae pneumonia Bacteria Streptococcus pyogenes Cellulitis Bacteria impetigo, erysipelas, cellulitis, flesheating disease (necrotizing fasciitis), and other syn-dromes not related to skin infection like pharyngitis Erysipelas is a Streptococcus pyogenes infection in the skin and must be treated promptly and effec-tively so as produces many toxins and enzymes as virulence factors - M protein inhibits phagocytosis and aids the adherence of bacteria to host cells - Erythrogenic toxin: produces the rash seen in “scarlet fever” and Spe toxins both are superantigens - Streptokinase: dissolves blood clots, allowing bacteria to spread - not to spread to deeper layers or systemically Hyaluronidase: breaks down connective tissue - Deoxyribonuclease: degrades DNA - Proteases (e.g., IgA protease): degrades IgA, which is on mucosal membranes and traps bacteria in mucus, which prevents bacteria from attaching to the host cells and infecting Streptococcus agalactiae Bacteria Streptococcus faecalis Bacteria Streptococcus faecium Bacteria Listeria monocytogenes Human infections: meningitis, encephalitis, septicemia, and spontaneous abortion in pregnant women. In animals: CNS (central nervous system) infections in Bacteria Facultative Gram + cocci in chains Beta hemolytic Group B Facultative Gram + cocci in chains Enterococci Y hemolytic Facultative Gram + cocci in chains Enterococcus Bacilli Gram (+) Coagulase (+) Nonspore forming Facultatively anaerobic motile Normally exists in soil and water and is found in animal intestines. Grows at refrigerator temperatures. and over a wide pH range (5.5–9.5) and in high salt concentrations - vague- Incubation period is long [several months before disease is noticed] Lab diagnosis can be difficult. - Foodborne disease. Food products at risk are coleslaw, soft unpasteurized cheeses, turkey wieners and other sliced cold meats, mushrooms, and prepack-aged salads - Vague symptoms in beginning so it can stay hidden but is fatal. symptoms include: queasiness, goats and cattle “circling disease;” also septic abortion. Corynebacterium diphtheriae Actinomyces Diphtheria Pathogenesis: fecal - oral -> invades macrophages to multiply -> creates actin tail from macrophage which it uses to shoot its DNA into other cells Bacteria Bacilli Gram (+) Coagulase (+) Nonspore forming Aerobic Non-motile Has reserve nutrient reserve deposits bacteriophage Bacteria unwellness, CNS infections, abortion, meningitis, encephalitis, septicemia, death - Sore throat, fever, malaise, bull neck swelling, nerve paralysis - *leather-like white-gray pseudo membrane at the back of the throat Bacilli Gram (+) Coagulase (+) Nonspore forming aerotolerant B. anthracis Bacteria Bacilli Gram (+) Coagulase (+) Spore forming Aerobic B. cereus Bacteria Bacilli Gram (+) Coagulase (+) Spore forming Aerobic Clostridium difficile Bacteria Bacilli Gram (+) Coagulase (+) - watery diarrhea, dehydration - AAD (antibiotic associated diarrhea) - AAC (antibody associated tis) - CDAD (C. diff associated diarrhea) Spore forming Anaerobic - PMC (pseudomembranous colitis) - Toxic megacolon (gangrene of intestines) - Death children <2 years of age NEVER get C. difficile Clostridium perfringens Bacteria Clostridium botulinum Bacteria Bacilli Gram (+) Coagulase (+) Spore forming Anaerobic Bacilli Gram (+) - GI infections, gastroenteritis - abdominal pain, diarrhea, - Pigbel (gangrene of intestines) in those who lack trypsin or eat trypsin inhibitors - botulism - neuromuscular paralysis - flaccid paralysis in baby - spastic paralysis (lockjaw) Coagulase (+) Spore forming Anaerobic Clostridium tetani Bacteria Bacilli Gram (+) Neisseria gonorrhoeae Bacteria Coagulase (+) Spore forming Anaerobic Diplococci Gram (-) Fridge temprature Neisseria meningitidis Bacteria Cocci Gram (-) Meningococcal meningitis - inflammation/infection of meninges - headache, stiff neck, photosensitivity, nausea, sore throat, petechiae/purpura, coma, death Meningococcal sepsis - replication of bacteria in the bloodstream - fever, petechiae/purpura, shock, hemorrhage, DICinternal organ meltdown, eventual death - Droplet transmission (cough, sneeze and saliva) Moraxella catarrhalis Bacteria Diplococci Gram (-) Aerobic Transmission: Droplet Escherichia coli (including O157:H7) Bacteria Bacilli Gram (-) Facultative aerobe Pseudomonas aeruginosa Bacteria Bacilli Gram (-) Obligate aerobe Non-spore forming Produces a gray-green or Coagulase (+)-green pus (Coagulase (+)-green colour caused by pigment called pyocyanin in some strains) Bacilli Gram (-) Facultative anaerobe Motile Nonspore forming Transmission: Fecal-oral Opportunistic; found in burn patients, colonizes lungs in cystic fibrosis patients *resistant to many antibiotics → hard to treat Symptoms: - High Fever* (over 40 Celsius) - Headache - Sometimes diarrhea (not main characteristic) Treatment: No antibiotics given unless sepsis occurs Salmonella enterica salmonellosis Bacteria Salmonella typhi Typhoid fever Bacteria Bacilli Gram (-) Facultative aerobe Shigella species Bacteria Bacilli Gram (-) Facultative aerobe Campylobacter jejuni Bacteria Bacilli Gram (-) Facultative aerobe Normal flora in daycare children’s nasopharynx Associated with diseases: - Pneumonia (not common, high risk for cancer patients) - Otitis Media (middle ear infection, buildup of fluid behind eardrum → can lead to deafness) - Sinusitis Vibrio cholerae Bacteria Bacilli Gram (-) Facultative aerobe Yersinia enterocolitica/pestis Bacteria Bacilli Gram (-) Facultative aerobe Helicobacter pylori Bacteria Bacilli Gram (-) Facultative aerobe Haemophilus influenzae Bacteria Bacilli Gram (-) Facultative aerobe Bordetella pertussis Bacteria Bacilli Gram (-) Facultative aerobe Pasteurella multocida Bacteria Bacilli Gram (-) Facultative aerobe Bartonella species Bacteria Bacilli Gram (-) Facultative aerobe Francisella tularensis Bacteria Bacilli Gram (-) Facultative aerobe Acinetobacter species Bacteria Bacilli Gram (-) Facultative aerobe Bacteroides Bacteria Bacilli Gram (-) Anaerobic Fusobacterium Bacteria Gram (-) Bacilli Anaerobic Mycobacterium tuberculosis Bacteria cell wall not stainable Mycobacterium leprae Bacteria Mycoplasma pneumoniae Bacteria Treponema pallidum syphilis Bacteria Chlamydia trachomatis Bacteria Entamoeba histolytica protozoa Giardia lamblia giardiasis protozoa Trichomonas vaginalis protozoa Acanthamoeba species protozoa Cryptosporidium parvum protozoa Toxoplasma gondii protozoa cell wall not stainable no cell wall; unstainable too small to see in Gram’s stain have axial filament Intracellular; too small to see in gram stain Single celled parasite Single celled parasite Single celled parasite Single celled parasite Single celled parasite Use Acid Fast Stien Single celled parasite Trypanosoma cruzi protozoa Trypanosoma brucei protozoa Leishmania species protozoa protozoa Plasmodium falciparum protozoa Plasmodium malariae protozoa Plasmodium vivax protozoa Plasmodium ovale protozoa Plasmodium knowlesi protozoa Single celled parasite Single celled parasite Single celled parasite Single celled parasite Single celled parasite Single celled parasite Single celled parasite Single celled parasite Single celled parasite metazoa Helminths Nematode (roundworm) Ascaris lumbricoides metazoa Helminths Nematode (roundworm) Trichuris trichiura metazoa Helminths Nematode (roundworm) Enterobius vermicularis pinworm Hookworm metazoa Helminths Nematode (roundworm) Anisakis metazoa Helminths Nematode (roundworm) Trichinella metazoa Helminths Nematode (roundworm) metazoa Helminths Nematode (roundworm) Schistosoma haematobium Metazoa helminths Trematodes (flukes/ flatworms) Schistosoma japonicum Metazoa helminths Trematodes (flukes/ flatworms) Schistosoma mansoni Metazoa helminths Trematodes (flukes/ flatworms) Filaria blood roundworms (general) Taenia saginata Beef tapeworm Metazoa helminths Cestodes (tapeworm) Taenia solium Pork tapeworm Metazoa helminths Cestodes (tapeworm) Echinococcus Metazoa helminths Cestodes (tapeworm) Sarcoptes scabiei Metazoa Pediculus humanus Metazoa Ectoparasite Ectoparasite Phthirus pubis Metazoa Candida albicans Cryptococcus neoformans/ gattii Fungi Meningitis Gatti = pneumonia Pneumocystis jiroveci Malassezia furfur Saccharomyces sp. Fungi Fungi Tinea versicolor Fungi Fungi Ectoparasite Single celled yeast may attach to epithelial cells as a yeast but invades deeper through the tissues by means of pseudohyphae Single celled yeast Use negative staining In pigon droppings and environment Targets immunocompromised Capsule Identified in CSF Single celled yeast Single celled yeast Superficial mycosis Black and white piedra (hairs of scalp) Single celled yeast Cutaneous mycoses Epidermophyton is a dermatophyte and causes ringworm or “tinea” (cutaneous mycoses). This type of fungus produces keratinase which breaks down keratin in skin for nutrients and restricts the infection to keratin containing skin. Systemic mycoses in deep tissue & Opportunistic pathogens - Antifungal agents have some problems with toxicity due to the fungi being eukaryotes. Amphotericin B has been the most commonly used systemic drug due to relatively minor side effects. - The major problem with treatment of fungal infections is to ensure adequate penetration of the antifungal drug to the site of infection. Lengthy treatment is often necessary (months rather than days) - Amphotericin B = treatment - Caused by primary pathogens (e.g., Histoplasma capsulatum, Coccidioides immitis, Sporothrix schenckii, Penicillium marneffei, Paracoccioides brasiliensis, etc.) or by opportunistic fungi (e.g., Candida albicans and Aspergillus species) o Aspergillosis: often caused by Aspergillis niger, infects people with debilitating lung diseases and immunocompromised individuals. Often cause granulomas and may appear as fungal “balls” in the lung tissue o Candidiasis: Candida albicans causative agent; vulvovaginal candidiasis and thrush; occurs in newborns, the immuno-compromised, or people who have been treated with antibiotics. This yeast is part of the normal flora of the intestines. o Mucor infection: often associated with diabetes Protozoa Entamoeba histolytica: causative agent of amoebic dysentery; invasive o -Fecal–oral transmission; ingestion of cysts (cyst wall breaks down in the gut, releasing the tropho-zoite form, which is actively invasive and can bind to intestinal cells, using cysteine proteases to penetrate through the mucin layer). o -Can also be transmitted sexually in the trophozoite form, from mucous membrane to mucous membrane -These are the only pathogenic amoeba found in the human intestine; need to differentiate from apathogenic species, which may look the same in the microscope. E. histolytica has an adhesin, Gal/GalNac-binding lectin differentiates the pathogenic amoeba from the non-pathogenic amoeba (e.g., E. dispar) o -Primary food is the red blood cell; ulcer formation is a result o -Known to cause “flask-shaped ulcers”—broad based with small opening o -Can exist as both trophozoite and cyst in humans o Increased resistance to chlorine o FIGURE 5.2 Entamoeba histolytica ulcer on a flank o Treat with metronidazole or antiparasitic drugs Giardia lamblia: causative agent of giardiasis or “beaver fever” o -Flagellate (motile by whipping of flagella) -Fecal–oral transmission (or sexual transmission) o -Found in small intestine of many animals (cyst dissolved by stomach acid and the trophozoite attaches to the mucous membranes in the duodenum and small intestine, covering the surface, and not allowing any reabsorption of nutrients) o -Causes intestinal upsets, flatulence, nausea, abdominal pain, and diarrhea o -Exists as both trophozoite and cyst o -Cysts survive well in environment and have increased resistance to chlorine o -Treat with metronidazole or antiparasitic drugs o FIGURE 5.3 Cyst of Giardia lamblia in a fecal concentrate Image Acanthamoeba species o -Causes inflammatory eye infections, especially in contact lens wearers o -Found in water and dust -Exists as both cyst and trophozoite form o -Important for contact lens wearers: eye loss is a possible outcome; important to use sterile solutions for contact lens cleaning, NOT tap water o -Difficult to treat; may need surgical interventions (like cornea transplants) o FIGURE 5.4 Trophozoite of Acanthamoeba in a bronchial wash specimen Trichomonas vaginalis: causes a STI o -Flagellate, motile o -No cyst stage, dries out easily; therefore, must be transferred from person to person quickly: mucous membrane to mucous membrane -Found in vagina and male urethra o -Causes intense itching and inflammation of the genitals o -Can be treated with metronidazole o FIGURE 5.5 Trophozoites of Trichomonas vaginalis Microsporidia: obligate intracellular parasites o -Opportunistic parasites -From cows, rats, dogs, and cats -Humans ingest the spores, enter host cells and grow into schizonts o -Cause chronic diarrhea, keratoconjunctivitis, gall bladder infections, and respiratory infections in immunocompromised o -Fecal–oral transmission o -Often implicated in outbreaks, swimming pools, and contaminated water ingestion o -Relatively resistant to chlorine o -No good treatments available o FIGURE 5.6 Microsporidia spores in a fecal concentrate Cryptosporidia: common agent of waterborne diarrhea - Three types: o Cryptosporidium parvum** (most pathogenic) o Cyclospora cayetanensis o Isospora belli o -Fecal–oral transmission; found in the intestines of many animals (e.g., cows and pigs) o -Causes long-lasting diarrhea in the immunocompetent and chronic diarrhea in the immunosuppressed o -Oocysts have four sporozoites, which are released and then infect new cells in the intestinal wall -Relatively resistant to chlorine o -No good antimicrobial for treatment: use supportive therapy with rehydration o FIGURE 5.7 Cryptosporidium parvum oocyst (red) in a fecal concentrate stained with modified Ziehl Neelson Toxoplasma gondii - -Life cycle in domestic cats (definitive host as the sexual reproduction takes place there)—cats do not get sick - -Trophozoites are called tachyzoites—the reproductive stage is in the cat, released as oocysts in feces. Other animals can ingest Toxoplasma oocysts; these cysts infect through the gut wall of these animals, and form tissue cysts with bradyzoites which can be ingested in meat products. This can lead to toxo-plasma infections acquired by eating rare meat. - -Dangerous for pregnant women if they have their first infection while pregnant but not if they have had an infection earlier - -Causes congenital infections in utero, especially dangerous for the foetus in the early stages of pregnancy - -Leads to stillbirths and fetal developmental problems - -Estimated that about 60% of 40-year-old women have been infected sometime (from antibody studies) - -Solution: pregnant and immunocompromised individuals should cook meats thoroughly and avoid direct contact with cat feces (also, hand washing is important after petting cats) Trypanosoma species -Blood parasites; can be transmitted by blood transfusion or by vectors (arthropods 5 insects) Trypomastigotes of Trypanosoma in a peripheral blood smear o T. brucei gambiense causes African Sleeping Sickness in Western and Central Africa o -Transmitted by a species of tsetse fly that frequents streams and is prevalent where there are large human populations o -Doesn’t infect animals, just humans; milder and more chronic infection than T. brucei rhodesiense, although end result is the same (if left untreated)—coma and death—CNS disease o -Symptoms might not appear until months after a bite o -More than 90% of cases of trypanosomiasis are gambiense o T. brucei rhodesiense causes African Sleeping Sickness in Eastern and Southern Africa where there are dry grasslands o -Wild animals in these areas have adapted to the parasite and are not affected,but humans and domes-tic animals get acutely ill o -Fast-progressing disease; symptoms within a few days of a tsetse fly bite, and death within a few months—CNS (central nervous system) disease o -Trypanosoma can change their surface antigens more than 100 times and thus evade the immune system—this is why there is no good vaccine yet o -Treatment in early stages can be effective with the new drugs on the market, like eflornithine, which is more successful against gambiense than rhodesiense. o T. cruzi causes Chagas disease in South America o -Vector is the kissing bug or reduviid bug o Chagas disease, very common in SA, cardiac complications, typical “eye of Romana,” 10% mortality – o Nifurtimox used for treatment of T. cruzi Leishmania species -About 20 different species cause disease, all transmitted by bites of flies (female sand flies) FIGURE 5.11 Sand fly, vector for Leishmania -Geographical distribution: subtropical and tropical areas of the world -infection of the parasite by a virus may influence the pathogenicity -Three major species: o L. donovani in tropics causes visceral leishmaniasis (parasites invade internal organs) o Disease is also called “kala-azar” (high mortality, malaria-like) o L. braziliensis causes mucocutaneous leishmaniasis o L. tropica causes Oriental sore or “rose of Jericho” (cutaneous leishmaniasis) o -Type of treatment depends on the species of Leishmania and the disease o FIGURE 5.13 Cutaneous leishmania with the original lesion spreading up the lymphatics o Babesia microti o -Tick-borne protozoal infection, Ixodes sp. (same tick that carries Lyme disease) o -Common in northeastern United States o -Protozoa enter and replicate in RBC (red blood cells); resemble plasmodium; end result hemolysis and anemia o -Relatively mild to moderate disease o FIGURE 5.14 Babesia microti in a peripheral blood smear Plasmodium species - Cause of malaria; worldwide problem -About 300 million people infected each year, causes 2 million to 4 million deaths/year -Four main types infect humans, but P. knowlesii (monkey malaria) is emerging as a significant zoonosis -All transmitted by female Anopheles mosquito a. Plasmodium falciparum o “Malignant malaria”; severe disease o Possess surface proteins like PfEMP1 for virulence o PfEMP1 changes the properties of the RBC they infect and make them “sticky”—will clump together and occlude capillaries o Ability to undergo antigenic variation to evade the immune system. -Problem with drug resistance o Mosdangerous o (cerebral malaria, extreme anemia, circulatory collapse) because it infects all ages of red blood cells, and the level of parasites in the blood gets very high (percentage parasitemia). o Mosquito bites the infected humans at night, ingests gametocytes; sexual cycle of reproduction is carried out in the mosquito gut, and sporozoites migrate to the salivary glands of the mosquito. When the mosquito then bites a new host, it injects the sporozoites with the saliva o Sporozoites migrate to the blood stream and liver within 30 minutes. o In liver, sporozoites enter liver cells and undergo schizogeny (asexual reproduction, where the nucleus divides many times before the cell divides) and release thousands of merozoites, which enter the blood stream, infecting red blood cells b. Plasmodium malariae o Parasite counts usually low; can cause chronic lifelong infections o Also called “quartian” malaria—fevers are at longer intervals than the other types of malaria c. Plasmodium vivax o Has the possibility to remain latent in the liver; this should be taken into consideration when choos-ing the treatment drug because only one will eliminate the latent “hypnozoites” o Mild clinical picture, low percentage parasitemia d. Plasmodium ovale o Has the possibility to remain latent in the liver for long periods o Mild clinical picture, lower percentage parasitemia e. Plasmodium knowlesii: emerging pathogen, zoonosis o “Monkey malaria”; high incidence in southeast Asia o Resembles P. malariae morphologically o Most cases are relatively mild o No drug resistance yet; easy to treat o Symptoms of malaria: Paroxyms (fever and chills): caused by the release of toxic breakdown products when the RBCs rupture and release more merozoites Anemia: lysis of red blood cells o High mortality rate in children -Individuals with sickle-cell trait have resistance to falciparum malaria o Diagnosed by blood smears (thick drop and thin smear); or RDT (rapid diagnostic tests) (antigen tests) o No good vaccine available; parasite has many life forms and can vary the antigens o Problem with rising resistance to antimalarials (e.g., chloroquine) Intestinal nematodes: Enterobius vermicularis (pinworm) o -Spends whole life cycle in human; no intermediate host o -Human to human infection; eggs infective stage o -Live in large intestine; females (about 1 cm long) migrate to anus and lay eggs o -Eggs are glued to the skin around the outside of the anus—this glue is very irritating and causes intense itchiness o -Usually not serious; causes anal itching but rarely can reach appendix or uterus o -Specimen taken by laying scotch tape against outside of anal opening and rolling it on a glass slide Ascaris lumbricoides o -Large, 30 cm when adult -Lives in small intestines of pigs, cows, and horses o -Eggs in soil are very hardy due to thick protein coat on egg; survive a long time o -Infection by “accidental ingestion” of eggs -Adult worms distinct sexes (dioecious) o -Diagnosis of infestation by examination of feces -Eggs reported as “fertilized or unfertilized”—this is important because if the eggs are fertilized, you know there may be a large infestation o -Eggs hatch in intestine of human host; larvae migrate to the lungs where they continue growth and development o -Can crawl up respiratory passages and exit by the nose or mouth (happens in children who do not have a good “swallow reflex,” but adults usu-ally just swallow them down to the stomach and intestines o -Rarely, larvae can also find their way to joints, where the adult worm may develop Trichuris trichuria (also known as “whipworm”) o -Relatively benign infestation of children; found in tropical and subtropical countries; associated with rat feces o -Small, slender worm o -Usually asymptomatic o FIGURE 5.20 Whipworm egg from a fecal specimen Hookworms o -Two species: o Necator americanus: sucks 0.03 ml blood/day (found in the Americas) o Ancylostoma duodenale: sucks 5X more blood/day (found in Africa, etc.) o -Can cause significant anemia -Only found in warm climates (tropical and subtropical) o -Eggs in soil hatch; infective stage larvae penetrate intact skin (i.e., soles of feet between toes); migrate to lymphatic system; then end up in the circulation o -Carried to lungs, coughed up, and swallowed down to small intestine, where they attach to mucosa with their “hooks” o -Can’t complete life cycle in host—eggs excreted to soil for recycling larvea in feces o Adult on intestinal mucus Strongyloides stercoralis o -Same method of infectivity as hookworm, but the female larvae penetrate the bowel wall and cause a generalized infection o -Eggs are not laid in intestine; larvae can be excreted, but there is no requirement for excretion to outside environment, thus “autoinfection” is common, where the larvae can reinfect while inside the body o -Usually cause abdominal pain and diarrhea; can also cause lung inflammation if the parasite is in the lung as well as skin lesions o -Chronic infections common especially in immunocompromised where, if the worm disseminates through the body, can cause septic shock and death o -Eggs are similar to hookworm but rarely seen; the larvae are similar o Larvae in feces Trichinella spiralis o Smallest nematode parasite of humans o -Acquired from infected undercooked meat—the larvae are in “nurse” cells in the striated muscle o -Nurse cells release larvae in the stomach because of the low pH; larvae then escape and enter the circulation and tissues, where they encyst and cause muscle weakness -Life cycle can be completed in one animal o -Bears, walrus, and pigs are very common sources of infection o FIGURE5.24 Encysted Trichinella spiralis in striated muscle Anisakis o -Small fish nematodes; accidentally infect humans (1–3 cm in length) o -Fishing practices (large catches, fish held for many hours in a hold before being gutted) contribute to increased rate of Anisakis in raw fish eaters Image o -Fairly uncommon, although increasing in prevalence with increased consumption of sushi (properly prepared fish for sushi will not have larvae in the meat) -Can also prevent this by heating fish to 60 °C for 10 minutes, blast-freezing to 235 °C for 16 hours, or freezing fish at 223 °C for a week Dracunculus medinensis (Guinea worm): o -Fecal–oral transmission, the growing larvae penetrate the intestines and travel in the subcutaneous tissues o -Can be up to 1 m in length o -Emerge from body by causing a blister, which erupts and the worm emerges—when it senses water, it releases larvae into the water, perpetuating the cycle o -Treatment: usually removal of worm (slowly winding it out 1 inch/day so as not to break it and cause undue inflammation) o -Probably the origin of the snake winding around the staff in the medical symbol (rod of Asclepius) o -WHO has an eradication program, which has been successful, and the number of cases are drastically decreasing in Africa Blood and tissue helminths (Filaria) -Main filarial infections in humans are: o Lymphatic filariasis (elephantiasis) o -Adult worms live in lymphatic tissue o Onchocerciasis (river blindness) o -Adult worms live in subcutaneous tissue o -Adult worms are infected by a bacterium (Wolbachia), which cause the intense inflammation in the eye, leading to “river blindness” -Transmitted by bites of mosquitoes -Microfilariae (offspring of adult worms) circulate through bloodstream or migrate through subcu-taneous tissue -Form lumps in skin—larvae seek oxygen and try to get to the surface. Diagnosis can be done by “skin snips,” where a lump is incised and the fluid examined in a microscope for microscopic worms -High prevalence in Africa, Asia, and tropical Latin America -Major species of filaria: Wuchereria bancrofti Brugia malayi Loa loa FIGURE 5.26a Wuchereria bancrofti in a peripheral blood specimen FIGURE 5.26b Elephantiasis in a patient from the Philippines Source Intestinal infection: mild clinical picture, produced by pork, beef, and fish or rodent tapeworms Deep tissue infection: serious infections, pork tapeworm (cysticercosis) or dog tapeworm (echinococcus) Taenia saginata o -Beef tapeworm; life cycle requires both humans and cattle -Infectious tissue larvae (cysticerci) are ingested by humans from infected, undercooked meat and mature into adult tapeworms in the intestine o -Adult worms can be as long as 10 m, attached to the intestinal wall by sucking discs on the head or “scolex” of the worm o -Hermaphrodites -Mild symptoms, if any, and no complications o -Segments of the tapeworm fall off the worm and can be excreted as whole segments or as individual eggs Taenia solium -Intermediate host is the pig, usually about 3 m, but can be longer as adult Two types of disease: o 1) Infection by egg: ingestion of eggs or segments (proglottids) with eggs; hatching of eggs in the intestine after passing through the stomach acid; larvae then escape and can migrate through the body. A preferred site for them to reside and become encysted is the brain. This can occur through autoinfection with an adult worm residing in the body. o 2) Infection by larvae: similar to T. saginata; ingestion of larvae, which survive stomach acid and attach to the intestinal wall with the suckers/hooks on their scolexes. Ribbon-band of segments form and either drop off as a whole or as eggs, which are released and excreted in feces .-Person-to-person transmission is possible; also autoinfection -Larvae in central nervous system encyst and are a major cause of seizures and syncope in many underdeveloped countries Diphyllobothrium latum o -Fish tapeworm; ingestion of larvae in undercooked contaminated fish (Scandinavia, Pacific north-west in North America) o -Can get to 10 m in length; attach to intestinal wall with grooves on the scolex o -Use vitamin B12 and cause B12 deficiency—with megaloblastic anemia -Mild to moderate symptoms, some diarrhea, abdominal pain o -Eggs are excreted in the feces Hymenolypsis nana o -Most common tapeworm globally, common in all tropical areas o -Small, 1–4 cm -Do not need an “intermediate host”—can autoinfect a human o -Few symptoms unless the worm infestation is huge -Infections by ingesting egg (fecal–oral transmission) o -Cysticeroid stage can develop in the intestine of humans in heavy infections—this can cause some tissue damage leading to symptoms of enteritis, diarrhea, cramps, etc. Echinococcus species (dog tapeworm) o E. multilocaris and E. granulosus most common o -Small tapeworm found in canines (dogs, coyotes, foxes, wolves), which are the definitive hosts where the sexual reproduction takes place o -Humans are accidental hosts if the eggs that canines excrete are ingested. Eggs hatch, and the larvae travel through the bloodstream to the organs where the hydatid cyst develops -Echinococcus forms “hydatid cysts” in liver or lungs (and other organs) of humans. These cysts are brood capsules and contain heads of tapeworms. These cannot develop into tapeworms in the human, but as they grow in size, they can cause irritation and inflammation and also tissue damage due to displacement of tissue o -If hydatid cysts are disrupted and break apart, this can cause life threatening shock in the human o -In Alberta most cases are due to Echinococcus granulosus, and most have cysts in the lungs. Surgery is not indicated normally due to the risk of rupturing the cyst and releasing anaphylactic (inflamma-tory) substances Termatodes – human Paragonimus westermani o -Intermediate host is fresh water snail, where the metacerceria develop o Humans ingest the metacerceria usually in seafood; these excyst in the duodenum, and the free lar-vae penetrate through to the lungs o -Infects human lungs and causes inflammation. Pseudotubercle formed; symptoms are cough and hemoptysis Clonorchis sinusensis (Chinese or Oriental liver fluke) o -Very common in the Far East; small fluke o -Intermediate host is the snail; cercariae released and enter a fish, where they develop into a cyst like metacerciaral structure o -Metacercariae in undercooked or raw fish muscle are ingested by humans; cyst is acid-resistant, so larvae hatch in the small intestine and migrate to the liver o -Live on bile and produce an inflammatory reaction in the gall bladder, bile ducts, and liver. Can obstruct the bile duct Schistosoma species – o Intermediate host fresh water snail; definitive host is the human; infected by cercariae that pen-etrate intact skin in contaminated waters – o Very important disease worldwide; causes debilitating disease o -Adult worms not affected by host immune system: they cover themselves with a protein layer that mimics host tissues o -Eggs reside in the venous plexus of bladder or intestine, depending on species Three main types of pathogenic Schistosoma in humans: o S. haematobium: urinary schistosomiasis ▪ -Results in inflammation of bladder wall ▪ -Chronic sequalae—bladder cancer ▪ -Found in Africa and the Middle East o S. japonicum: intestinal parasite, found in the Far East o S. mansoni: intestinal parasite, found in Africa, South America, and the Caribbean ▪ -More than 250 million people infected “Swimmer’s itch”: o caused by cercariae of nonhuman schistosome (ducks and other waterfowl) o -Do not enter the circulation; self-limiting infection in the skin, which causes intense itching o Different types of Schistosoma can be differentiated by the appearance of the eggs and source of spec-imen (urine for hematobium and feces for mansoni and japonicum). Nematode – zoonosis Ectoparasites Scabies o -Caused by Sarcoptes scabei var hominis (human scabies), an arthropod, 400 um mite o -Dog mange is caused by a closely related Sarcoptes species; does not cause human infection o -Infectious from human to human -Fertilized adult female burrows in the skin to lay eggs o -Presence of mites tunnelling in skin and the eggs cause an extensive allergic reaction, and the areas are excruciatingly itchy—can move up to an inch a minute o -Preferentially live on finger webs, elbows, armpits, and breasts and around the groin and buttock o s -Heavy infestations are called “Norwegian scabies” -Secondary infections with staphylococci and streptococci common Pubic lice or “crabs” (Phthirus pubis) and head lice (Pediculus humanus): o -Surface dwellers; do not burrow o -Feed by penetrating the skin with mouth and sucking blood o -Female pubic louse lays eggs (called nits) and glues them to hair shafts o -Eggs hatch in 5–10 days, releasing new lice o -Secondary infections when lice feces crushed into wounds Superbugs: Microbes that are resistant to antimicrobials and are hard to treat 1. MRSA (methicillin-resistant Staphylococcus aureus) o -Mutation involving the gene Mec A; PBP2 mutated to PBP2a 2. VRE (vancomycin-resistant Enterococcus species) o -Several gene mutations, genes Van A, Van B, Van C 3. ESBL (extended spectrum beta-lactamase) o -Gram-negative bacteria (Enterobactericeae family) o -Many different genes involved o -Increasing problem in ICU (intensive care units), extended care facilities o ESBL-producing bacteria can inactivate even the new really good beta-lactamase antibiotics like meropenem o -NDM-1 is an enzyme (New Delhi metalloproteinase) that makes bacteria extremely resistant to beta-lactam antibiotics 4. Pseudomonas aeruginosa o o o o o o -Gram-negative bacillus (nonfermenter of glucose) -“Opportunistic pathogen,” normal inhabitant of soil and water -Can live in very harsh conditions (e.g., liquid soap, Cepacol mouthwash) -Need very few nutrients (can live in water in flower vases) -Can infect many body sites -Very common in burns and lungs of cystic fibrosis patients -Endotoxin; also produces exotoxins 5. Streptococcus pneumoniae o o o o -Gram-positive diplococci; cause of upper and lower respiratory tract infections, meningitis -Most common cause of community-acquired pneumonia -Common pathogen in all ages of patients, children to elderly -Emerging resistance to penicillin due to genetic mutations in PBP (penicillin-binding protein) 6. Mycobacterium tuberculosis (MDR-TB, XDR-TB) -M. tuberculosis is always treated with a combination of drugs: First line: isoniazid, rifampin, pyrazinamide, ethambutol Second line: fluoroquinolones, aminoglycosides like amikacin, cycloserine, etc -Normally only first-line drugs used; patient becomes noninfectious in about two weeks o MDR-TB: multidrug-resistant TB: organism is resistant to isoniazid and rifampin by definition o XDR-TB: extensively drug-resistant TB: resistant to isoniazid and rifampicin and also any member of the quinolone family and at least one of the injectable drugs (like aminoglycosides) o -Second-line and third-line drugs are more toxic with more side effects than first line drugs o -Treatment might be necessary for up to two years Interlukin Autoimmune diseases Exotoxins viralSkin infections Aspergillus species fungi Aspergillis niger gungi Sporothrix schenckii Rose gardiner disease Fungi Many celled mold Aspergillosis Dimorphic Transmission from rose thorns, hay, moss, wood via puncture infects people with debilitating lung diseases and immunocompromised individuals. Often cause granulomas and may appear as fungal “balls” in the lung tissue A black necrotic lesion often develops at the site of inoculation, and the inflamma-tion often progresses along the lymphatics, causing lymphangitis (inflammation of the lymphatic channels). World wide Histoplasma capsulatum Fungi Coccidioides immitis Fungi Blastomyces dermatitidis Fungi Herpesviridae HSV DNA Virus Dimorphic Dimorphic Dimorphic Enveloped HSV-1 causes cold sores HSV-2 causes genital herpes Herpesviridae VZV DNA Virus Herpesviridae CMV DNA Virus Herpesviridae EBV DNA Virus Poxviridae Vaccinia cow pox DNA Virus Poxviridae Variola small pox DNA Virus Enveloped Enveloped Enveloped oncogenic Enveloped Enveloped Varicella zoster (chickenpox) Poxviridae Molluscum DNA Virus Poxviridae contagiosum DNA Virus Adenoviridae DNA Virus Adenoviridae DNA Virus Adenoviridae DNA Virus Papovaviridae HPV (human papilloma virus = wart virus) DNA Virus Enveloped Enveloped Not enveloped Upper respiratory tract Not enveloped Eye infections Not enveloped GI infection Not enveloped Not enveloped Papovaviridae Polyomavirus (JC virus) DNA Virus Parvoviridae B19 DNA Virus Hepadnavirus HBV DNA Virus Picornaviridae poliovirus RNA virus Picornaviridae HAV RNA virus Enterovirus Not developed Fecal oral [water] Enterovirus Not enveloped Picornaviridae Rhinovirus [colds] RNA virus Enterovirus Not enveloped Caliciviridae Norovirus [gastroenteritis] RNA virus Togaviridae Rubella RNA virus Flaviviridae HCV RNA virus Flaviviridae Yellow Fever RNA virus Flaviviridae Dengue RNA virus Coronaviridae SARS RNA virus Coronaviridae Common cold RNA virus Not enveloped Enveloped Not enveloped Enveloped Enveloped Enveloped Enveloped Enveloped Enveloped Paramyxoviridae PIV RNA virus Paramyxoviridae Measles RNA virus Paramyxoviridae mumps RNA virus Orthomyxoviridae Influenza A RNA virus Orthomyxoviridae Influenza B RNA virus Orthomyxoviridae Influenza C RNA virus Bunyaviridae Hanta RNA virus Reoviridae Rotavirus RNA virus Rhabdoviridae Rabies RNA virus Filoviridae Ebola RNA virus Retroviridae HIV RNA virus Retroviridae HTLV – I RNA virus Retroviridae HTLV - II RNA virus Babesia Enveloped Enveloped Enveloped Enveloped Enveloped Enveloped Enveloped Not Enveloped Enveloped Enveloped Enveloped Inactivated by disenfectants Blood or sex transmission [STI] Enveloped Enveloped Drucunculia Diphyllobothrium Hymenolypsis Smallpox A Gram-positive, anaerobic, diphtheroid bacillus, which is often a causative organism for acne – Multifactorial blockage in channels transporting sebum to surface P. Acnes Propionibacterium acnes -Secondary infection drives the pustular skin disease (could be with S. aureus) Mycobacterial skin diseases HFM disease 5th disease Atypical bacterial pneumonia fungal pneumonia CMV pneumonia Covid - 19 Gingivitis periodontitis V. Cholerae Leptospirosis Childbed fever Vaginosis Gas gangrene Leprosy Relapsing fever Tularemia brucella Kaposi’s sarcoma STD