Essential concepts in medical Bacteriology - Mathilde Lescat

The essential concepts to know in MEDICAL BACTERIOLOGY

Mathilde Lescat Assistant Professor, Université Paris Sorbonne Nord, France

Major families of bacteria

Staphylococci Streptococci Enterococci Anaerobes (Peptostreptococcus sp)

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Gram + cocci

Gram - bacillus

Gram - cocci

Gram + bacillus

Intra cellulaires

Mycobacteria

Neisseria meningitidis Neisseria gonnorhoeae Anaerobes (Veillonella sp)

Corynebacteria Listeria monocytogenes Anaerobies (Clostridium sp)

Enterobacteriaceae Parvobacteria (Haemophilus sp, HACCEK, Pasteurella sp, Brucellla melitensis, Bartonella sp) Strict aerobic (Pseudomonas aeruginosa) Anaérobies (Bacteroides sp, Prevotella sp...)

Intracellular bacteria

Chlamydiae sp, Mycoplasma sp Legionella pneumophila Ricketsiae, Coxiella sp

Spirochetes

Treponema pallidum Borrelia burgdorferi Leptospira sp

Diagnosis by standard culture

Diagnosis by serology, specific culture or molecular biology

The great commensal sites

Skin microbiota: Staphylococci, corynebacteria

Oropharyngeal / nose microbiota: Streptococci, Neisseria sp, Hemophilia, Staphylococcus aureus, Chlamydiae, Mycoplamses, Anaerobes (Veillonella sp ...)

Vaginal microbiota: Lactobacilli +++, Mycoplasmas, Enterobacteriaceae and Enterococci transiently

Digestive microbiota: Anaerobes ++++ (Bacteroides sp, Clostridium sp ...) Enterobacteriaceae (E. coli), enterococci (Enterococcus faecalis)

Main commensal sites in animals and vectors associated with anthropozoonoses

Rickettsia sp Yersinia pestis

Rickettsia sp, Borrelia sp

Pasteurella multocida, Bartonella henselae

Coxiella burnetti Brucella melitensis Escherichia coli O157:H7

Leptospires,

Chhlamydiae psitacci

Saprophytic bacteria from the environment

Strict aérobic Gram negative bacteria (Pseudomonas aeruginosa)

Listeria monocytogenes

Legionnella pneumophila

Vibrio cholerae, Aeromonas hydrophila

The main infections

Skin infections: Staphylococcus aureus, Streptococcus pyogenes Material associated: Pseudomonas aeruginosa, Staphylococci, Enterobacteriaceae

Lung infections: Community: Streptococcus pneumoniae, Haemophilus influenzae, atypical (Chlamydiae, Mycoplasmas, Legionella) Nosocomial: Enterobacteriaceae Staphylococcus aureus, Pseudomonas aeruginosa

Genital infections low: Gonococci, Chlamydiae, Syphilis, High: Enterobacteriaceae, Anaerobes Maternal-fetal infections: E. coli, Streptococcus agalactiae, Listeria

Digestive infections Ulcers: Helicobacter pylori Extraintestinal: Anaerobes, Enterobacteriaceae, Enterococci Diarrhea: Salmonella, Shigella, Yersina enterocolytica, Campylobacter sp

Meningitis (adult, child) Streptococcus pneumoniae, Neisseria meningitidis, Listeria monocytogenes

Endocarditis: Streptococci, Staphylococci

Urinary tract infections Enterobacteriaceae (E. coli), enterococci (E. faecalis), Streptococcus agalactiae, Staphylococus saprophyticus

Main resistances to antibiotics

New targets, or modification of existing targets

ATB destruction

Decreased ATB concentration

Target Modification

Enzymes

Efflux, Impermeability

MDRO and (multi drug resistant organisms)

MRSA

Multiresistant Pseudomonas aeruginosa and Acinetobacter baumanii

ESBL Gram negative producers

Carbapenem Enterobacteriaceae producers*

Vancomycin resistant enterococci*

*emerging highly resistant bacteria

The main first-line treatments

Skin infections Amoxiciilin, Amoxicillin-clavulanate

Lung infections: Communautary: Amoxicillin-clavulanate, Amoxicillin, C3G, Macrolide Nosocomial: Tazocillin

Genital infections Low: tetracycline, macrolide, Fluoroquinolone (CT) 3rd generation cephalosporin (NG) High: 3rd generation cephalosporin+ metronidazole + tetracycline Maternal fetal infections: 3rd generation cephalosporin, amoxicillin

Digestive infection Ulcers: Chlarythromycin Extra intestinal: Amoxicillin-clavulanate, 3rd generation cephalosporin + metronidazolel, tazocillin Diarrhea: Doxycycline, Fluoroquinolone

Meningeal infections (adult, child) 3rd generation cephalosporin vancomycin, amoxicillin

Endocarditis 3rd generation cephalosporin , Amoxicillin + aminoglycoside

Urinary tract infections Cystitis: Fosfomycin, sulfamethoxazole, Fluoroquinolone High: 3rd generation cephalosporin, fluoroquinolone