The Quizzes about Rickettsiae, Chlamydiae and Mycoplasma

Mycoplasmas have been cultivated from human mucous membranes and tissues, especially from the genital, urinary, and respiratory tracts. Chlamydia can be isolated from many of these sources as well. Both cause respiratory and genital tract infections. Adults may present with asymptomatic respiratory infection to serious pneumonitis, and identification of the etiologic agent usually determines the best antimicrobial treatment. Which of the following best describes the difference between mycoplasmas and chlamydiae?

A 39-year-old man presents with sudden, influenza-like symptoms. He states that he works in a slaughterhouse, and several of his coworkers have similar symptoms. Early stages of pneumonia are detected. Which of the following is the most likely etiologic organism?

Many survivors of military or natural disasters are at risk of infection due to loss of public health services. Rickettsial infections—except Q fever and the ehrlichiosis—typically are manifested by fever, rashes, and vasculitis. Which of the following best characterizes rickettsiae, which include the spotted fevers, Q fever, typhus, and scrub typhus?

A man with chills, fever, and headache is thought to have “atypical” pneumonia. History reveals that he raises chickens, and that approximately 2 weeks ago he lost a large number of them to an undiagnosed disease. Which of the following is the most likely diagnosis of this man’s condition?

An ill patient denies being bitten by insects. However, he spent some time in a milking barn and indicates that it was dusty. Of the following rickettsial diseases, which one has he most likely contracted?

A 23-year-old college senior presents to the student health clinic with symptoms of a suspected sexually transmitted disease (STD). Neisseria and chlamydia agents are ruled out. Which of the following organisms is the most likely cause of his nongonococcal urethritis (NGU)?

A young man, home on leave from the military, went camping in the woods to detect deer movement for future hunting. Ten days later, he developed fever, malaise, and myalgia. Leukopenia and thrombocytopenia were observed, as well as several tick bites. Which of the following statements best describes human monocytic ehrlichiosis (HME)?

A couple, who did not know each other very well, dated and had sexual contact. Several weeks later, the man noticed a small, painless vesicle on his penis, which ruptured and then healed. Soon, his inguinal lymph nodes enlarged and discharged pus through multiple sinus tracts. Lymphogranuloma venereum (LGV) is a venereal disease caused by serotype L1, L2, or L3 of Chlamydia trachomatis. The differential diagnosis should include which of the following?

The differential diagnosis of LGV includes syphilis, genital herpes, and chancroid. Several clinical tests can be used to rule out syphilis and genital herpes. These include a negative (negative to rule out; positive to rule in) dark-field examination as well as positive sero-logic findings for syphilis and the demonstration of herpes simplex virus by cytology or culture. Haemophilus ducreyi can usually be isolated from the ulcer in chancroid. Babesiosis is an RBC-infecting tick-borne disease, usually derived from dogs or Texas cattle. Most cases are asymptomatic, but clindamycin or azithromycin are effective treatments. Mononucleosis is seen most often in infectious mononucleosis caused by EBV. Psittacosis is caused by inhaling aerosols or direct contact with birds infected with C.psittaci and is usually a mild upper respiratory illness. Shingles would be evidenced by masses of painful herpetic lesions caused by reactivation of VZV (chicken pox).

Chlamydiae are true bacteria with an unusual three-stage cycle of development. These characteristics are important to understand to be able to distinguish them from other bacteria and viruses that can cause similar disease presentations and choice of treatments. For the growth of Chlamydia, which of the following is the correct sequence of these events?

Young children in a small Egyptian village have eye infections that present with lacrimation, discharge, and conjunctival hyperemia. Scarring of the conjunctiva and noticeable loss of vision occur in some. Which of the following statements best describes the etiologic agent that caused these infections and relative treatment?

The ehrlichia group organisms are obligate intracellular bacteria that are taxonomically grouped with the rickettsiae and have tick vectors. Human granulocytic ehrlichiosis (HGE) is a disease transmitted to humans by the bite of a tick, Ixodes scapularis. Three ehrlichia species are present in different parts of the United States and produce inclusions in circulating WBCs. Which of the following statements about HGE is correct?

The “spotted fever” group of rickettsial diseases is caused by a variety of rickettsial species. While not critical for treatment of disease, the speciation of these organisms is essential for epidemiologic studies. Which of the following rickettsiae is found in the United States and is a member of the spotted fever group?

A 36-year-old man presents to his primary care physician’s office complaining of fever and headache. On examination, he has leucopenia, increased liver enzymes, and inclusion bodies are seen in his monocytes. History reveals that he is outdoorsman and that he remembers removing a tick from his leg. Which of the following is the most likely diagnosis?

Rickettsial organisms infect humans worldwide, although geographic locations may be limited for some species and possibly produce some challenges in medical diagnosis. All are obligate intracellular parasites, except C. burnetii, and transmitted by an insect vector. Typhus, spotted fever, and scrub typhus share which of the following manifestations of disease?

Humans are the natural hosts for C. trachomatis, which is widespread in the population and a well-known cause of STD. The organism is a well-documented cause of NGU in men and urethritis, cervicitis, and pelvic inflammatory disease in women. This organism is also implicated in which of the following?

A homosexual male presents to his physician with bilateral inguinal buboes (lymph nodes), one of which seems ready to rupture. He recalls having two small, painless genital lesions that healed rapidly. The etiologic agent is isolated using McCoy cells. Which of the following statements best characterizes LGV?

Dozens of political refugees fleeing from active warfare and living in a dense forest environment with crowded, unsanitary conditions experienced nonspecific symptoms, followed by high fever, severe headache, chills, myalgia, and arthralgia. All had body lice. Improved living conditions in a refugee camp and treatment with tetracycline brought resolution to most individuals. Which of the following statements describes the etio-logical agent responsible for their infection?

An 18-year-old student develops symptoms consistent with primary atypical pneumonia (PAP). This is generally a mild disease, ranging from subclinical infection to serious pneumonitis; the latter characterized by onset of fever, headache, sore throat, and cough but requires laboratory tests to determine which organism is involved and a basis for antimicrobial choices. Which of the following organisms causes this disease in humans?

NGU is the most common STD in men. Within 2 weeks, the symptoms usually include painful urination and a urethral discharge. Because ofthe similarity of NGU symptoms with Neisseria gonococcus infection, diagnosis depends on culture of the discharge. While the majority of NGU are caused by C. trachomatis, which of the following organisms is very significant in causing additional cases in humans?

A healthy oral cavity has a microbial population consisting of gram-positive streptococci and diphtheroids. Anaerobic rods and spirochetes are present in low numbers and may be opportunistic for disease. Which of the following organisms also normally inhabits the healthy human oral cavity?

At least 15 species of Mycoplasma are of human origin, and five are of primary importance. Which of the following organisms normally inhabits the female genital tract and is strongly associated with salpingitis and ovarian abscesses?

Suppurative inguinal adenitis usually starts by the appearance of small, painless lesions on the external genitalia that heal spontaneously. Then regional lymph nodes enlarge and become painful and often discharge pus through multiple sinus tracts. Which organism listed below is responsible for this STD?

Which of the following is transmitted by the bite of a hard Ixodes tick, where circulating leukocytes are infected and morulae (clusters of microorganisms) form, which can be treated with tetracyclines and rifamycins?

Six laboratory technicians at the state health laboratory were working on a study using rabbits. The experiments involved an outbreak of acute febrile illnesses in workers from a slaughterhouse. The organism of interest was a gram-negative bacterium with tropism for mononuclear cells. A dysfunction of the animal cage air safety system allowed contaminated air to escape into the animal care facility and research laboratories. Four of the six technicians now suffer from a flu-like illness and pneumonitis. Which organism listed below is most likely the cause of this outbreak?

A 56-year-old woman in Uganda presents to an emergency clinic. The woman is homeless and extremely dirty. She is also very dehydrated and the duty nurse notices lice in her hair and clothing. The patient reported high fever, severe headaches, and muscle pain. A petechial rash was observed all over her body. After 72 hours in the hospital, the woman died. A Gram-stain of the organism showed a weakly staining Gram-negative bacterium that could not be grown in vitro. What organism was the most likely cause of her infection?

A 25-year-old male patient presents to the emergency room in July in Texas. He complains of shortness of breath and a low-grade fever. The emergency room physician suspects tracheobronchitis. The patient also complains of a dry, nonproductive cough. A patchy bronchopneumonia was observed on x-ray. Cold agglutinins were observed in the patient’s serum. The physician suspects a Mycoplasma pneumoniae infection. Which of the following antibiotics does the physician know that he cannot or should not administer in this situation?

A 45-year-old man living in Uganda presents to the emergency clinic. He complains that he has a “groin swelling.” He says that this “groin swelling” has broken open and a thick, white fluid has leaked out. This patient stated that he had been sexually active for 30 years and that he observed a “sore” on his penis about a month ago. The patient also complained of recent headaches, fever, and muscle pain. A bacterium was isolated from this thick white fluid, but it would not grow in vitro. It would only grow in tissue culture. The organism was a Gram-negative rod. Which of the following bacteria was the cause of this man’s infection?

A week after returning from a July camping trip to the Blue Ridge Mountains in North Carolina, a 10-year-old boy is brought to the emergency room with a severe headache, fever, and muscle pain. He also has a maculopapular rash on his arms and legs. Although the rash began on his arms and legs, it has now spread to his trunk. He remembers removing several ticks from around his ankles on the camping trip. What is the organism most likely to the cause of this young man’s infection?

A 19-year-old college student presents to the university infirmary with what the doctor thought was NGU. The physician had a very hard time isolating a causative organism from the young man. The clinical lab finally got the organism to grow in vitro and they reported that the offending organism produced extremely small colonies and would only grow in the presence of urea. The organism often died rapidly after the initial isolation. The organism causing this student’s NGU was which of the following?

A 15-year-old boy presents to his family doctor and reports that he was not feeling very good. He says that he has been feeling “lousy” for the past 2 weeks with a fever, runny nose, headaches, and no energy. He also has a nonproductive cough. The doctor orders a pulmonary x-ray that demonstrates no consolidation and only patchy opacity in the lower lobes of the lungs. The boy’s serum is positive for cold agglutinins and antibodies against Streptococcus MG. Which of the following bacteria is responsible for his infection?

A 40-year-old man develops a cough that is nonproductive and goes to see his family doctor. He says that he has been feeling “lousy” and has bronchitis, sinusitis, and a sore throat. The doctor orders an x-ray that does not show consolidation, but rather a patchy infiltrate in his upper right lung. The man denies taking any new pets or animals recently into his house. A Gram-stain of the sputum specimen shows a few Gram-negative rods that do not stain very well. Samples sent to the clinical laboratory do not grow on normal laboratory media (eg, blood agar), but do grow in monolayer cells in tissue culture. What bacterium is most likely to be the cause of this man’s infection?

A 35-year-old woman living in Minnesota goes to her family physician. She complains that for the past 8 days she has experienced a flu-like illness. The illness consisted of muscle pain, lethargy, headaches, and a high fever (almost 41°C). She states that she had removed several ticks from around her ankles about 14 days ago. The physician gives her a shot of penicillin, but when she returns to see him about a week later, she reports no improvement. The physician then draws her blood and submits it to a clinical laboratory for identification. No bacteria grew out on blood agar, but a Giemsa stain of the blood culture showed coccobacillary organisms inside polymorphonuclear neutrophils. Which of the following bacteria was most likely to be the cause of her illness?

A 27-year-old man presents to his family doctor because he has been having a mucopurulent discharge from his penis. He had recently visited a prostitute and he had unprotected sex with her. He was afraid that he had caught the “clap”. He did not have a fever and he said he experienced no pain upon urination. The doctor noted a white urethral discharge from the man’s penis. This discharge was then sent to the clinical laboratory. Because the physician suspected Neisseria gonorrheae infection, the lab stained the specimen and tried to grow it on blood agar. The causative organism did not grow on blood agar, but would only grow in certain cells lines. What was the organism that caused this man’s infection?

A physician was asked to come to an Indian reservation in South Dakota because of an outbreak of a serious eye infection. The infection was believed to have spread from person to person by infected towels at the gymnasium. Patients reported conjunctivitis with widespread inflammation. In some cases, the patient’s conjunctiva became so damaged, that the eyelids turned inward, thus scratching the eyeball every time they blinked. In some patients, there was corneal scarring and invasion of blood vessels into the cornea. Fortunately, the physician recognized what the disease was, its cause, and how to treat it. He administered azithromycin in one dose and the infections resolved. What organism was causing the described symptoms?

A 45-year-old man reported to the emergency room in respiratory distress. His symptoms included muscle pain, congestion, a dry cough, and difficulty breathing. He also was experiencing fever and chills. A chest x-ray showed consolidation of the left lower lobe, and a patchy infiltrate of his right upper lobe. He was given a shot of penicillin and hospitalized. He did not improve on this antibiotic so he was given doxycycline, which allowed for his improvement. It was decided to give doxycycline after his attending physician learned he was a bird enthusiast and had recently received an African parrot that had arrived sick and had died. What was the name of the organism with which the man was infected?

A 50-year-old man presented to his family doctor complaining of flu-like symptoms. The doctor gave him a shot of penicillin and sent him home. The man came back a week later and in fact, felt worse. The man was a rancher and raised a lot of cattle. He told the doctor that he had congenital heart disease and an attack of rheumatic fever when he was young. The man now complained of fever, night sweats, continual coughing, weight loss, and lethargy. The doctor had the man hospitalized because he now suspected subacute bacterial endocarditis (SBE). A culture of his blood did not show any bacterial growth, but a serum analysis for antibodies against a certain bacterium was positive. As a result of finding antibodies to this organism, treatment with doxycycline was begun and the patient improved and was released from the hospital. What was the name of the organism with which the man was infected?

In July of 1987 in Texas, a man went to his family doctor complaining of flu-like symptoms, high fever, lethargy, muscle pain, and a headache. He complained that he just felt “lousy”. When the doctor took the patient’s history, he learned that the man was an avid hiker and camper. In fact, the man just came back from a recent camping trip to South Carolina. The man remembered removing a blood-filled tick from his leg on that trip. He had killed the tick and thought nothing more of it. Now, he felt it might be relevant. The doctor also felt this information was relevant and asked for a Giemsa stain of the man’s blood by the clinical lab. The results came back stating that there were morulae inside the monocytes in the man’s blood. The doctor, based on these results, immediately started the man on doxycycline because he felt the man was infected with which organism?

A United States businessman presented to the emergency room in New York City. He complained of severe headaches, muscle pain, and fever. He had a maculopapular rash on his trunk that was moving to his arms and legs. The emergency room doctors were stumped as to what might be causing this disease state. When they took his history, he told them that he had just come back from a business trip to Japan where he had spent a few days camping in the mountains and had been bitten by some insects. He stated that he never saw the insects, so he did not know what kind they were. He said he knew what fleas and ticks looked like and he was sure that he was not bitten by either of those. In fact, he could show the doctors the eschars of the insect bites. When asked how long ago this was, he replied “about 11 days”. Because of this information gathered by taking the patient’s history, the emergency room doctors felt confident they knew what had caused the patient’s symptoms. They gave the patient doxycycline and told him to see his family doctor for a follow-up after 1 week. When this man went to his family doctor, he was greatly improved. What organism did the New York businessman have that had caused his infection?