Therefore, they are one of the oldest living organisms on the Earth. There are evidences suggesting that bacteria were in existence even 3.5 billion years ago. These microorganisms are found in soil, water, deep in the oceans, hot springs, radioactive waste - practically everywhere including the most extreme conditions! Bacteria also live in symbiotic and parasitic relationship with other organisms. They are usually sensitive to carbapenems such as meropenem or imipenem.Share on Twitter Facebook WhatsApp What is Bacteria?ĭefinition: Bacteria are single-cell, prokaryotic microorganisms.īacteria are present everywhere on the planet Earth, including on the bodies of other organisms and inside them too. coli or klebsiella and typically cause urinary tract infections but can also cause other infections such as pneumonia. They can be resistant to a very broad range of antibiotics.ĮSBLs tend to be e. They produce beta lactamase enzymes that destroy the beta-lactam ring on the antibiotic. Eradication usually involves a combination of chlorhexidine body washes and antibacterial nasal creams.Īntibiotic treatment options for MRSA are:Įxtended Spectrum Beta Lactamase bacteria (ESBLs)ĮSBLs are bacteria that have developed resistance to beta-lactam antibiotics. Patients being admitted for surgery or treatment are screened for MRSA infection by taking nasal and groin swabs so that extra measures can be taken to try to eradicate them and stop their spread. If these bacteria become part of an infection they can be difficult to treat. People are often colonised with MRSA bacteria and have them living harmlessly on their skin and respiratory tract. Think about MRSA in patients that have had hospital admissions or come from a nursing home or other healthcare institution. They are a problem in healthcare settings where antibiotics are commonly used. MRSA refers to staphylococcus aureus bacteria that have become resistant to beta-lactam antibiotics such as penicillins, cephalosporins and carbapenems. Methicillin-Resistant Staphylococcus Aureus (MRSA) The atypical bacteria that cause atypical pneumonia can be remembered using the mnemonic “ legions of psittaci MCQs”: Atypical bacteria are most often implicated in pneumonia. The definition of atypical bacteria is that they cannot be cultured in the normal way or detected using a gram stain. If the bacteria is not listed above then it is probably gram negative. Use the mnemonic “ corney Mike’s list of basic cars”: Then add a counterstain (such as safranin) which binds to the cell membrane in bacteria that don’t have a cell wall ( gram negative bacteria) turning them red/ pink. It involves two main steps:Īdd a crystal violet stain which binds to molecules in the thick peptidoglycan cell wall in gram positive bacteria turning them violet. PABA is then converted to DHFA which is converted inside the cell to THFA then folic acid.Ī gram stain is used as a quick way to check a sample under the microscope to look for bacteria. This chain starts with PABA, which is directly absorbed in to the cell across the cell membrane. Folic acid cannot be created or directly imported into the cell and requires a chain of intermediates to get in to the cell. Ribosomes are where bacteria proteins are synthesised within the bacterial cell.įolic acid is essential for synthesis and regulation of DNA within the bacteria. Nucleic acid is essential component of bacterial DNA. The cell wall is a structure that surrounds the outer cell membrane and is found on gram positive bacteria. There are some key components to learn about as they are the target of antibiotic treatment: Rod shaped bacteria are called bacilli and circular shaped bacteria are called cocci. Atypical bacteria cannot be stained or cultured in the normal way.īacteria can also be classified based on their shapes. Gram negative bacteria don’t have this thick peptidoglycan cell wall and don’t stain with crystal violet stain but will stain with other stains. Gram positive bacteria have a thick peptidoglycan cell wall that stains with crystal violet stain. Learning where bacteria fall within these categories helps you work out which antibiotics will be effective against them.Īerobic bacteria require oxygen whereas anaerobic bacteria do not. They can be categorised into aerobic and anaerobic, gram positive and gram negative and atypical bacteria. These pathogenic bacteria are the most relevant to learning medicine. Most bacteria are not harmful however some are pathogenic and cause infectious diseases.
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