Dr Peter Gayo Munthali Consultant Microbiologist, UHCW Honorary Associate Clinical Professor University of Warwick Common Infections

Objectives By the end of this session you will be able to do the following; Microbiologically diagnose and treat the following conditions by using appropriate investigations and by selecting appropriate antibiotics based on scientific rationale; –Central Nervous System infections –Skin and soft tissue infections –Joint infections –Respiratory Tract Infections –Urinary tract infection

Case 1 A normally fit and well 17 yrs old student is admitted with 1/7 history of fever, headache and nauseaA normally fit and well 17 yrs old student is admitted with 1/7 history of fever, headache and nausea Pyrexia 38.6ºCPyrexia 38.6ºC BP 100/69BP 100/69 HR 120b/minHR 120b/min Starts vomiting in A&EStarts vomiting in A&E

PMHx nilPMHx nil SHx nil, lives in halls of residence at Warwick university. Sometimes has alcohol binges at weekendsSHx nil, lives in halls of residence at Warwick university. Sometimes has alcohol binges at weekends O/E – some mild neck stiffness, slight photophobiaO/E – some mild neck stiffness, slight photophobia Widespread skin lesionsWidespread skin lesions History & Examination

Considering the history given and examination, Q1. What is the Diagnosis a)Sepsis b)Thrombotic Thrombocytopenic Purpura (TTP) c)Meningitis d)Migraine Q2. Choose 4 most important microbiological investigations and 4 other important investigations to manage the case? Q3. Name two most important causes of this condition in this age group? Q4. Which of these antibiotics can be used to treat this condition and state why? a)Benylpenicillin b)Gentamicin c)Meropenem d)Ciprofloxacin e)Cefuroxime Q5. What is the role of public health in this condition?

Initial CSF Result on Day 1

More Results on Day 1 (Normal g/l) (Normal mmol/L) (Normal mmol/L)

Final CSF Report on Day 3

CSF Findings in Meningitis Cells/mm³ (0-5) Gram stain Bacterial Ag Detection Protein g/l (N ) Glucose mmol/l (N ) Viral10¹-10³ (Lymphocytes) -Ve Normal or slightly ↑ Usually normal Bacterial10¹-10^4 (mainly polymorphs) ± Ve+VeHigh<60% of blood glucose TB10¹-10³ (mainly lymphocytes) ±-VeHigh or very high <60% of blood glucose Note: 5-10% of CSF may be normal in early stages of meningococcal meningitis Lactate is increased in bacterial and TB meningitis BUT NOT in viral meningitis

How Do You Adjust WCC in Bloody CSF For every RBCs, deduct 1 WCC from the WCC Examples RBC 640 x 10^6/L, WCC 4940 x 10^6/L Corrected WCC 4939 x 10^6/L RBC x 10^6/L, WCC 49 x 10^6/L RBC ÷ 700 = WCC = <1 Conclusion WCC is normal

Q3. Name two most important causes of this condition in this age group?

Which of these antibiotics can be used to treat this condition and state why?

AntibioticClassPenetration into CSF Activity (Inhibit) Comments Benzylpenicillin/ Amoxicillin Beta lactam (Penicillin) YesCell wall synthesis- Bactericidal Some pneumococci may be resistant Ceftriaxone/ Cefotaxime Beta lactam (Cephalosporins) YesCell wall synthesis- Bactericidal No activity against Listeria monocytogenes MeropenemBeta lactam (Carbapenem) YesCell wall synthesis - Bactericidal GentamicinAminoglycosideNoProtein synthesis- Bactericidal NEVER to be used CiprofloxacinQuinoloneNo/poorly DNA synthesis- Bactericidal VancomycinGlycopeptideVariableCell wall synthesis- Bactericidal ChloramphenicolStand-aloneYesProtein synthesis- Bactericidal/ Bacteriostatic Bactericidal in CSF against pneumococcus, H influenzae and Neisseria meningitidis

Q5. What is the role of public health in this condition?

A 44 year old man is admitted with confusion, fever and change in personality. What is the diagnosis? What one important laboratory study would you like to confirm the diagnosis?

Causative OrganismDuration of Treatment Meningococcal meningitis ≥ 5 days Pneumococcal meningitis ≥ days* Haemophilus influenzae meningitis ≥ 10days Listeria monocytogenes ≥ days* TB meningitis ≥ 12 months* HSV/VZV Encephalitis≥ days* Cryptococcal meningitis ≥ 10 weeks* Treatment Duration *Longer duration of treatment may be required

Case 2

A normally healthy 40year old man comes in with a two day history of fever, rigors and swollen left knee

Q1. What is the likely diagnosis? Q2. What two tests can you do to confirm the diagnosis? L R Q3. Name two most important causes of this condition? Q4. What agents would you use to treat this condition

Case 3

25 yr old admitted with T 38ºC, right sided abdominal pain and dysuria PMH. Admitted with similar condition without abdominal pain. U&Es: Urea 10.6 Creatinine 170 Q1. What is the likely diagnosis ? a)Ectopic pregnancy b)Sexually transmitted infection c)Pyelonephritis d)UTI Q2. Which of these investigations will be useful? a)B/C b)MSU c)Pregnancy test d)Ultrasound scan Q3. Which of the markers below can help with the diagnosis of this patient? Q4. Name three most common causes of this condition?

Case 4

A 66 year old man, unwell for 5 days after returning from holiday in Benidorm, Spain. T 38ºC, cough productive of small amounts of sputum, mildly confused and short of breath. Had Amoxicillin 250mg TDS by his GP without improvement. O/E, RR 35breaths/minute, Pulse 100b/min, BP 99/60mmHg, Peripheral shutdown O2 saturation 90% on 40% O2 Q1. Which of these is the likely diagnosis? a)Massive Pulmonary embolus b)Exacerbation of COPD c)Community acquired pneumonia (CAP) d)Pulmonary Tuberculosis Q2. How would you grade the severity of this condition? Q3. Which bedside/laboratory test can be used to help with diagnosis within three hours?

Treatment? PneumococcusPneumococcus –Penicillin HaemophilusHaemophilus –Amoxicillin LegionellaLegionella –Macrolide

Hospital Acquired Pneumonia Microbiology –Anticipate Gram negative bacilli More resistant –Less Pneumococcus –Legionella –MRSA pneumonia

Case 5

28 year old male PE instructor, recently travelled around US, where he camped in several areas of the country and sustained multiple tick bites. He returned yesterday. On presentation he has slight erythema around the bite site on left lower leg. Clinical Progress While in ED spikes temps up to 39ºCWhile in ED spikes temps up to 39ºC He says he has severe pain in leg despite unimpressive erythema of the legHe says he has severe pain in leg despite unimpressive erythema of the leg FY1 reviews patient one and half hours later and notices dark erythema spreading up as far as thigh with some blisters developingFY1 reviews patient one and half hours later and notices dark erythema spreading up as far as thigh with some blisters developing Patient says he has less pain now than when he presented 2 hours agoPatient says he has less pain now than when he presented 2 hours ago BP 90/50mmHgBP 90/50mmHg

Q1. What is the likely diagnosis? Q2. Name 5 findings in the clinical history and examination that make this diagnosis likely A B C Q3. Which of these organisms is the likely cause of this condition? Q4. Name two modalities of treatment?

Gram Stain Beta haemolytic Group A