Microbiology Flashcards
What is the risk of wound infection occurring in a 43 year old woman who is undergoing a laparoscopic choelcystectomy for uncomplicated biliary colic?
2% 5% 15% 20% 30%
5%
The incidence is higher because it is a clean contaminated wound. If there is a bile spill the risks increase and intravenous antibiotics should be given perioperatively.
A 22 year old man presents with a painless penile ulcer and marked inguinal lymphadenopathy. Some of the exudate from the lesion is sent for microscopy. What organism is most likely to be visualized?
Treponema pallidum Nocardia asteroides Mycobacterium tuberculosis Mycobacterium leprae Neisseria gonorrhoea
Treponema pallidum
A hard painless ulcer affecting the genital area of a young male is likely to be the primary lesion of syphilis and that is caused by treponema pallidum. It would be unusual for actinomycosis to affect this area.
A 68 year old man with poorly controlled diabetes presents with severe otalgia and headaches. On examination, there is granulation tissue within the external auditory meatus. What is the most likely underlying infective agent?
Pseudomonas aeruginosa Streptococcus pyogenes Staphylococcus aureus Actinomyces Bacteroides fragilis
Pseudomonas aeruginosa
Severe pain, headaches and granulation tissue within the external auditory meatus are key features of malignant otitis externa. Diabetes mellitus is one of the commonest risk factors.
A 23 year old woman is admitted with sepsis and right loin pain. She has a history of a UTI that was treated by the GP with a course of trimethoprim that was commenced 24 hours previously. Which of the organisms listed below is the most likely cause?
Bacteroides fragilis E-Coli Clostridium difficile Candida albicans Mycobacterium tuberculosis
E-Coli
Ascending infection of the genitourinary tract is most commonly caused by E-Coli. Other organisms may be accountable, however, these are less common
A 30 year old aid worker becomes unwell whilst helping at the scene of a recent earthquake. He develops vomiting and soon afterwards a diarrhoea that is loose and extremely watery. What is the most likely infective organism?
Campylobacter jejuni Vibrio cholera Enterohaemorragic E Coli Clostridium perfringens Clostridium boltulinum
Vibrio cholera
The passage of very loose and watery stools distinguishes cholera. Most gastroenteric infections do not produce such watery motions.
A 45 year old man is recovering in hospital following a total hip replacement. He develops a profuse and watery diarrhoea. Several other patients have been suffering from similar symptoms. Infection with which of the following is the most likely underlying cause?
Clostridium perfringens Clostridium botulinim Clostridium difficile Clostridium welchi Clostridium tetani
Clostridium difficile
Clostridium difficile can spread rapidly on surgical wards. The use of broad spectrum prophylactic antibiotics during arthroplasty surgery can increase the risk.
A 28 year old chef presents to the medical team with profuse bloody diarrhoea. On further questioning he describes tenesmus. They arrange a sigmoidoscopy which reveals necrosis and ulceration of the descending colon mucosa. What is the most likely cause?
Ischaemic colitis Infection with Yersinia pestis Infection with entero invasive E Coli Infection with campylobacter Infection with vibrio cholera
Infection with entero invasive E Coli
Necrosis and ulcers of the large bowel are a feature of enteroinvasive E.coli. It presents with a dysentery type illness similar to shigellosis.
What is the likely risk of surgical wound infection in a 23 year old male undergoing an elective inguinal hernia repair?
Between 5 and 10% Less than 5% Between 10 and 15% More than 25% Between 15 and 20%
Less than 5%
This is a clean procedure and carries the lowest risk of SSI. That is why it is safe to use meshes in these settings.
A 34 year old homosexual is admitted with diarrhoea of 3 months duration. He is found to be HIV positive with a CD4 count <50. Which of the organisms listed below is most likely to be responsible?
Cryptosporidium Adenovirus Norovirus Vibrio cholera Clostridium difficle
Cryptosporidium
Although a self limiting diarrhoea is the norm, this is not the case in immunocompromised individuals who can develop severe illness. Other organisms may include Salmonella, Shigella, and Campylobacter.
A 62 year old lady is unwell following a difficult acute cholecystectomy for acute cholecystitis. Her gallbladder spilled stones intraoperatively and she has been on ciprofloxacin intravenously for this for the past 4 days. She now has colicky abdominal pain and profuse, foul smelling diarrhoea. Which of the organisms below is likely to account for this illness?
E-Coli Clostridium difficile Clostridium perfringens Clostridium tetani Campylobacter
Clostridium difficile
C. difficile may complicate administration of broad spectrum antibiotics.
A 68 year old man with diabetes presents with an area of necrosis of the perineum at the base of the scrotum, there is some surrounding erythema. He is systemically unwell and hypotensive. Which of the following organisms is likely to be accountable?
Clostridium tetani Staphylococcus epidermidis and streptococcus viridans Bacteroides and staphylococcus saprophyticus Streptococcus viridans and bacteroides E-coli and bacteroides
E-coli and bacteroides
This is likely to be Fournier’s Gangrene. A number of agents are implicated. E-coli and bacteroides are the most commonly isolated organisms. The key point is that both aerobic and anaerobic organisms must be present.
A 53 year old man presents with an ulcerated mass at the anal verge. A biopsy is taken and the histology demonstrates as squamous cell carcinoma. Infection with which of the viruses below is most likely to have contributed to the development of the condition?
Human papillomavirus 7 Human immunodeficiency virus 1 Human immunodeficiency virus 2 Human papillomavirus 16 Human T-lymphotropic virus 1
Human papillomavirus 16
Infection with human papilloma virus 16 is a risk factor for the development of intra epithelial dysplasia of the anal skin with subsequent increased risk of invasive malignancy.
A 58 year old man undergoes a difficult colonoscopy for assessment of a caecal cancer. 48 hours after the procedure he is admitted with septicaemia. His abdomen is soft and non tender. Blood cultures grow gram positive cocci. What is the most likely underlying organism?
Staphylococcus epidermidis Streptococcus pyogenes Streptococcus bovis Clostridium difficle Bacteroides fragilis
Streptococcus bovis
Streptococcus bovis septicaemia is associated with carcinoma of the colon. It also can also cause endocarditis.
A 29 year old female undergoes a sub total thyroidectomy. Five days post operatively the wound becomes erythematous and discharges pus. What is the most likely causative organism?
Streptococcus pyogenes Haemophilus influenzae Pseudomonas aeruginosa Staphylococcus aureus Proteus mirabilis
Staphylococcus aureus
In this setting Staphylococcus aureus Infection is the most likely cause. In the UK between 2010 and 2011 the commonest cause of wound infection was enterobacter infections (usually following cardiac or colonic surgery). 23% of infections were due to Staph aureus, which fits the scenario above. Infection with the other organisms including strep pyogenes was much rarer.
Which of the following cancers is not associated with the human papillomavirus?
Anal cancer Oropharyngeal cancer Tracheal cancer Vulval cancer Penile cancer
Tracheal cancer
HPV is associated with:
- Cervical cancer (HPV 16/18 most common)
- Anal cancer
- Penile cancer
- Vulval cancer
- Oropharyngeal cancer
A 21 year old man is admitted with crampy abdominal pain and diarrhoea. He attended a large wedding earlier in the day. Several other guests are also affected with the same illness. Which of the organisms is likely to be accountable?
Staphylococcus aureus E-Coli Salmonella Clostridium perfringens Campylobacter
Clostridium perfringens
C. Perfringens is a common cause of food borne illness and its ability to form spores may make it relatively resistant to cooking. The timing of onset would favor C. Perfringens which typically evolves over several hours, rather than staphylococcus aureus poisoning which may occur sooner.
Which of the following is not associated with Epstein-Barr virus?
Burkitt's lymphoma Post-transplantation lymphoma Hodgkin's lymphoma Nasopharyngeal carcinoma Mycosis fungoides
Mycosis fungoides
Which organism is most likely to cause osteomyelitis in children with sickle cell disease?
Group A Streptococcus species Staphylococcus aureus Enterobacter Salmonella species Group B Streptococcus species
Salmonella species
Worldwide the Salmonella species remains the most common infecting organism in children with osteomyelitis. Reference: Etiology of Osteomyelitis Complicating Sickle Cell Disease (Burnett, et al. Pediatrics 1998; 101:2 296-297)
A 28 year old lady is breast feeding her first child. She presents with discomfort of the right breast. Clinical examination demonstrates erythema and an area that is fluctuant. Aspiration and culture of the fluid is most likely to demonstrate infection with which of the following organisms?
Lactobacillus caseii Staphylococcus aureus Streptococcus pyogenes Staphylococcus epidermidis Actinomycosis
Streptococcus pyogenes
Staphylococcus aureus is the commonest cause. The infants mouth is usually the source as it damages the nipple areolar complex allowing entry of bacteria.
A 22 year old man has undergone an inguinal hernia repair. Seven days later he presents with an erythematous and tender wound that is discharging a purulent material. What is the most likely cause?
Infection with Staphylococcus aureus Discharging haematoma Infection with Pseudomonas Infection with Streptococcus pyogenes Infection with Bacteroides
Infection with Staphylococcus aureus
In this setting Staphylococcus aureus Infection is the most likely cause. In the UK between 2010 and 2011 the commonest cause of wound infection was enterobacter infections (usually following cardiac or colonic surgery). 23% of infections were due to Staph aureus, which fits the scenario above. Infection with the other organisms including strep pyogenes was much rarer.
An enthusiastic watercress farmer is admitted with a protracted history of severe abdominal pain, fevers and progressive jaundice. Imaging with ultrasound shows mildly dilated bile ducts with hyperechoic areas within them. What is the most likely cause?
Fasicola hepatica Clonrochis sinesis Entamoeba histiolytica Viral hepatitis Leptospirosis
Fasicola hepatica
The watercress history is important here as fasicola hepatica is most classically transported to humans through eating watercress. The USS finding of luminal parasites is classical and its this that contributes to jaundice.
A 22 year old female is admitted to A&E with a splenic rupture. She has not been involved in any trauma. What infection can cause spontaneous splenic rupture?
Measles Mumps Influenza Epstein-Barr virus Rubella
Epstein-Barr virus
Epstein - Barr Virus may cause generalised lymphadenopathy. This may be associated with splenomegaly. This enlargement has been associated with spontaneous rupture
A group of consultant surgeons are meeting at a symposium. The chef preparing the canapes has an infection on his finger. Approximately 40 minutes after eating the canapes the group are struck down with severe vomiting. What is the most likely underlying explanation for this process?
Presence of enterotoxin from Staphylococcus aureus in the food Presence of enterotoxin from Streptococcus pyogenes in the food Infection with Campylobacter jejuni Presence of enterotoxin from Clostridium perfringens in the food Infection with Shigella soneii
Presence of enterotoxin from Staphylococcus aureus in the food
Staphylococcus aureus may release an enterotoxin, this is preformed and thus will typically result in rapid onset of symptoms in affected individuals.
What is the mechanism of action of macrolides?
Causes misreading of mRNA Interferes with cell wall formation Inhibits DNA synthesis Inhibits RNA synthesis Inhibits protein synthesis
Inhibits protein synthesis
Macrolides act by inhibiting bacterial protein synthesis. If pushed to give an answer they are bacteriostatic in nature, but in reality this depends on the dose and type of organism being treated. Erythromycin was the first macrolide used clinically. Newer examples include clarithromycin and azithromycin.
A 22 year old lady is breastfeeding her first child. One week post partum she presents with a tender indurated mass in the right breast. Infection with which of the following is most likely?
Staphylococcus aureus Streptococcus pyogenes Streptococcus bovis Klebsiella Streptococcus viridans
Staphylococcus aureus
Staphylococcus aureus is the commonest cause of lactational mastitis.
A 58 year old man is reviewed in the clinic following a successful cadaveric renal transplant the previous year. He has been able to return to work as a swimming instructor. Over the past week he reports that he has been suffering from recurrent episodes of diarrhoea. It has made him feel lethargic and exhausted. Stool microscopy shows evidence of cysts. What is the most likely source of infection?
Enterobius vermicularis Clonorchis sinensis Giardia Ascaris lumbricoides Cryptosporidium
Cryptosporidium
Cryptosporidium is associated with infection, particularly in those who are immunocompromised. Diarrhoea is the main disease. The cysts are typically identified on stool microscopy.
A 22 year old Chef presents with abdominal pain in the right iliac fossa. There is an associated temperature and diarrhoea. The CT1 takes the patient to theatre for an appendicectomy, but the appendix appears normal. The terminal ileum appears thickened and engorged. Infection with which of the following is most likely?
Yersinia enterocolitica Yersinia pestis Salmonella Vibrio cholera Entero invasive E Coli
Yersinia enterocolitica
Yersinia can be mistaken for acute appendicitis due to mesenteric lymphadenitis and ileitis. Yersinia infection of the terminal ileum typically produces more marked clinical changes of this segment of bowel than infection with campylobacter. Yersinia pestis causes plague.
Which of the following is true regarding the Salmonella species?
Rose spots appear in all patients with typhoid They are normally present in the gut as commensals Subsequent chronic biliary infection occurs in 75% of cases A relative bradycardia is often seen in typhoid fever Salmonella typhi can be categorised into type A, B and C
A relative bradycardia is often seen in typhoid fever
The Salmonella group contains many members, most of which cause diarrhoeal diseases. They are facultative anaerobes, Gram negative rods which are not normally present as commensals in the gut.
Typhoid and paratyphoid are caused by Salmonella typhi and Salmonella paratyphi (types A, B & C) respectively. They are often termed enteric fevers, producing systemic symptoms such as headache, fever, arthralgia
A 77-year-old female presents with a non-healing ulcer on her right foot. Blood cultures grow MRSA. Which antibiotic would you consider in addition to vancomycin to cover this?
Flucloxacillin Ceftazidime Ciprofloxacin Metronidazole Rifampicin
Rifampicin
The MRSA would or may be resistant to Other antibiotics. Rifampicin is normally given in combination with another antibiotic.
A 48 year old lady undergoes an ERCP for jaundice. 36 hours following the procedure she develops a fever and rigors. A blood culture is taken, which of the following organisms is most likely to be cultured?
Pseudomonas aeruginosa Streptococcus Enterobacter Staphylococcus Escherichia coli
Escherichia coli
E Coli is the most common organism implicated in cholangitis infections. Whilst enterobacter is occasionally cultured it is not the most common organism.
In a 72 year old man undergoing a sigmoid colectomy for diverticular disease, which of the following interventions is most likely to reduce his risk of developing a post operative wound infection?
Using a plain clear incise type drape to cover the operative field Administering mechanical bowel preparation pre operatively Shaving his abdominal wall one day prior to surgery Administration of single dose of broad spectrum antibiotics prior to the procedure None of the above
Administration of single dose of broad spectrum antibiotics prior to the procedure
Administration of prophylactic antibiotics will reduce the risk of wound infection. Plain incise drapes increase the risk of wound infections and should not be used. Iodophor impregnated drapes have been demonstrated to reduce the risk of wound infection. Shaving one day prior to surgery will increase the risk.
A 27-year-old male presents to urology for investigation of pyelonephritis. He reports malaise, pyrexia, lymphadenopathy and a maculopapular rash. The Monospot test is negative. Given a history of recent high-risk sexual behaviour you are asked to exclude a HIV seroconversion illness. What is the most appropriate investigation?
Antibodies to HIV-2 gp120 polymerase chain reaction p24 antigen test CCR5 polymerase chain reaction Antibodies to HIV-1
p24 antigen test
A 22 year old man presents with a 5 day history of sore throat, malaise and fatigue. On examination, he has a large peritonsillar abscess. What is the most likely underlying infective organism?
Epstein Barr Virus Streptococcus pyogenes Cytomegalovirus Moraxella catarrhalis Streptococcus viridans
Streptococcus pyogenes
Quinsy usually occurs as a result of bacterial tonsillitis and the most common cause of bacterial tonsillitis is streptococcal organisms.
Which of the following statements relating to osteomyelitis is false?
Is the result of haematogenous spread in most cases Is due to Staphylococcus aureus in 50% cases Should be treated by aggressive surgical debridement initially Plain radiographs may be normal in the early stages The presence of associated septic joint involvement will significantly alter management
Should be treated by aggressive surgical debridement initially
It is managed medically in the first instance (with an antistaphylococcal antibiotic). This differs from the situation in septic joints where early joint washout is mandatory.
A 32 year old woman undergoes mastectomy and latissimus dorsi flap reconstruction for breast cancer, to provide optimal cosmesis a McGhan implant is placed under the myocutaneous flap. Three weeks post operatively the patient continues to suffer from recurrent wound infections that have proved resistant to multiple courses of antibiotics. Which of the organisms listed below is most likely to be responsible?
Staphylococcus epidermidis Staphylococcus aureus Streptococcus viridians Streptococcus pyogenes Staphylococcus saprophyticus
Staphylococcus epidermidis
This tends to colonise plastic devices and forms a biofilm which allows colonisation with other bacterial agents. It is notoriously difficult to eradicate once established and the usual treatment is removal of the device
A 48 year old lady is admitted with crampy abdominal pain and diarrhoea. She has been unwell for the past 12 hours. In the history she complains that her milk bottles have been pecked repeatedly by birds, she otherwise has had no dietary changes. Which of the following is the most likely causative organism?
Staphylococcus aureus Campylobacter jejuni Clostridium difficile Norovirus Clostridium botulinum
Campylobacter jejuni
Birds are a recognised reservoir of campylobacter.
A 50-year-old female with a history of rheumatoid presents with a suspected septic knee joint. A diagnostic aspiration is performed and sent to microbiology. Which of the organisms below is most likely to be responsible?
Staphylococcus aureus Staphylococcus epidermidis Escherichia coli Neisseria gonorrhoeae Streptococcus pneumoniae
Staphylococcus aureus
Septic arthritis - most common organism: Staphylococcus aureus
A 22 year old man presents with crampy abdominal pain diarrhoea and bloating. He has just returned from a holiday in Egypt. He had been swimming in the local pool a few days ago. He reports that he is opening his bowels 5 times a day. The stool floats in the toilet water, but there is no blood. What is the most likely cause?
Cryptosporidium Salmonella sp E.coli sp Chronic pancreatitis Giardia lamblia
Giardia causes fat malabsorption, therefore greasy stool can occur. It is resistant to chlorination, hence risk of transfer in swimming pools.
A 6 year old boy presents with symptoms of recurrent pruritus ani. On examination, there is evidence of a small worm like structure protruding from the anus. What is the most likely infective organism?
Echinococcus granulosus Enterobius vermicularis Ascaris lumbricoides Ancylostoma duodenale Clonorchis sinensis
Enterobius vermicularis
Infection with enterobius is extremely common. Pruritus is the main symptom, as there is a lack of tissue invasion it is rare for individuals to have any signs of systemic sepsis
A 54-year-old female is admitted one week following a cholecystectomy with profuse diarrhoea. Apart from a minor intra-operative bile spillage incurred during removal of the gallbladder, the procedure was uncomplicated. What is the most likely diagnosis?
Campylobacter infection E. coli infection Clostridium difficile infection Salmonella infection Pelvic abscess
Clostridium difficile infection
Antibiotics are not routinely administered during an uncomplicated cholecystectomy. Indications for administration of broad spectrum antibiotics include intraoperative bile spillage. Delayed pelvic abscesses following bile spills are extremely rare since most surgeons will manage these intra-operatively.
Which of the following is not a feature of Campylobacter jejuni infection?
Infection may present in a similar manner to acute appendicitis Pyrexia is unusual They are gram negative organisms Infection accounts for 26% case of Guillain-Barre syndrome It is the commonest cause of infective diarrhoea arising from non viral causes
Pyrexia is unusual
A prodromal period of fever and generalised malaise precedes abdominal pain (which may mimic appendicitis) and diarrhoea.
A 68 year old women with previous rheumatic fever is admitted with pyrexia of unknown origin. Her blood cultures are unhelpful but transoesophageal echocardiography reveals vegetations on the mitral valve. Infection with which of the following organisms is most likely?
Staphylococcus aureus Streptococcus pyogenes Streptococcus viridans Staphyloccus epidermidis Staphylococcus saprophyticus
Streptococcus viridans
This is the most common organism affecting previously abnormal heart valves.
A 53-year-old woman is diagnosed with cellulitis surrounding her leg ulcer. A swab is taken and oral flucloxacillin is started. The following result is obtained:
Skin swab: Group A streptococcus
How should the antibiotic therapy be adjusted?
No change Add topical fusidic acid Add clindamycin Add penicillin Add erythromycin
Add penicillin
Penicillin is the antibiotic of choice for group A streptococcal infections. The BNF suggests stopping flucloxacillin if streptococcal infection is confirmed in patients with cellulitis, due to the high sensitivity. This should be balanced however with the variable absorption of phenoxymethylpenicillin.
Which of the following statements related to necrotising fasciitis is false?
Mainly polymicrobial A feature may include 'dirty dishwater fluid' in the wound The presence of crepitus is needed to make the diagnosis Further surgery is mandatory 24-48h after initial surgery to review extension of infection The muscles are relatively spared
The presence of crepitus is needed to make the diagnosis
Crepitus may be present in only 35% of cases, therefore its absence should not exclude a diagnosis of necrotising fasciitis.
A surgical trainee is incising a groin “abscess” in an intravenous drug abuser. Unfortunately the “abscess” is a false aneurysm and torrential bleeding ensues. In the panic of the situation the doctor then stabs himself in the finger. It transpires that the patient is a Hepatitis B carrier and the doctor is not immunised! What type of virus is Hepatitis B?
Double stranded DNA virus Single stranded DNA virus Double stranded RNA virus Single stranded RNA virus Retrovirus
Double stranded DNA virus
Hepatitis B is a double-stranded DNA virus and is spread through exposure to infected blood or body fluids, including vertical transmission from mother to child. The incubation period is 6-20 weeks.
What is the commonest cause of an amoebic liver abscess?
Hydatid disease Clonorchiasis Entamoeba histolytica Fasicola hepatica Giardia
Entamoeba histolytica
Entamoeba histiolytica is the only agent on the list that would produce an amoebic abscess.
A 23 year old man is readmitted following a difficult appendicectomy. His wound is erythematous and, on incision, foul smelling pus is drained. Which of the organisms listed below is responsible?
Steptococcus bovis Bacteroides fragilis Staphylococcus aureus Streptococcus pyogenes Clostridium perfringens
Bacteroides fragilis
Bacteroides is commonly present in severe peritoneal infections and as it is facultatively anaerobic may be present in pus. It has a pungent aroma.
A 72 year old man with peripheral vascular disease develops a gangrenous toe. This becomes infected and there is evidence of infection in the surrounding tissues. On clinical palpation there is crepitus present within the tissues. What is the most likely infective organism?
Staphylococcus aureus Streptococcus pyogenes Clostridium difficile Clostridium perfringens Clostridium botulinum
Clostridium perfringens
Clostridium perfringens is the most likely pathogen to be associated with gangrene.
Which virus is implicated in cervical carcinoma?
Human papilloma virus 16 Human papilloma virus 2 Human herpes virus 8 Human herpes virus 2 Epstein-Barr virus
Human papilloma virus 16
Human papillomavirus 16/18 Cervical cancer Anal cancer Penile cancer Vulval cancer Oropharyneal cancer
A young woman is admitted to hospital with E-coli 0157 after visiting Germany during an outbreak. Which of the following is not true of the condition?
It may be complicated by micro-angiopathic haemolytic anaemia. Adults typically develop haemolytic uraemic syndome. It is most commonly transmitted by consumption of contaminated food. Plasmids typically confer antibiotic resistance. E-Coli is a gram negative organism.
Adults typically develop haemolytic uraemic syndome.
Children typically develop this complication.
What is the risk of a wound infection in a male undergoing a Hartmanns procedure for perforated sigmoid diverticular disease?
35% 15% 10% 20% 80%
35%
These infected cases carry a high risk of wound infection. In really heavily contaminated cases, some surgeons do not close the skin at all.
A 22 year old man returns to the UK from holiday in India. He presents with painless jaundice. On examination he is not deeply jaundiced and there is no organomegaly. What is the most likely cause?
Hepatitis E infection Hepatitis A infection Malaria Gilberts syndrome Gallstones
Hepatitis A infection
Infective hepatitis is the most likely cause. In the UK, foreign travel is a common cause of developing infectious hepatitis, of which hepatitis A is the most common.
A 25 year old man returns from a backpacking holiday in India. He presents with symptoms of coughing and also of episodic abdominal discomfort. Peri anal examination is normal. Stool microscopy demonstrates both worms and eggs within the faeces. What is the most likely infective organism?
Cryptosporidium Ancylostoma duodenale Clonorchis sinensis Ascaris lumbricoides Enterobius vermicularis
Ascaris lumbricoides
Infection with Ascaris lumbricoides usually occurs after individuals have visited places like sub Saharan Africa or the far east. Unlike ancylostoma duodenale infection there is usually evidence of both worms and eggs in the stool. The absence of pruritus makes enterobius less likely. The presence of coughing may be due to the migration of the larva through the lungs.
Which statement relating to actinomycosis is false?
They are gram positive bacilli They are strict aerobes It may be a cause of chronic multiple abscesses Abdominal cases may develop in the appendix Open biopsy of the lesions is the best diagnostic test
They are strict aerobes
They are facultative anaerobes and may be difficult to culture. Direct visualisation of organisms and sulphur granules from lesions themselves is the easiest way to make a diagnosis. It remains a differential of conditions such as hydradenitis supprativa, particularly if it is occurring in odd locations and with deeper abscesses than usual.
