SPUTUM CULTURING - CLINICAL UTILITY OF LABORATORY REPORTS
Dr.T.V.Rao MD A frequent specimen in our diagnostic laboratories is Sputum for Microscopy and culturing, we all have experienced many specimens sent as sputum are not sputum just saliva, nobody bothers to instruct the patients to send the better specimens, repeated instructions make no difference, many casually report and get rid of the matters, However to improve the matters Care must be taken in the sample collection process to ensure that the sample is from the lower airways and not from the upper respiratory tract. Sputum samples may be expectorated or induced I spoke on many occasion the greater failure of Microbiology lies with poor collection of specimens, clinicians too are not serious or wait for the reports, all the good efforts of microbiology go to files but not for utility. I always wonder so much human resource is wasted on many matters, from collecting the samples to processing with valuable media and chemicals, and at the end unfollowed results
HOW WE PROCESS THE SAMPLES Typically, the first step in the routine analysis of a sputum sample is a Gram stain to identify the general type of bacteria that may be present. The sample is then placed on or in appropriate nutrient media and incubated. The media encourages the growth of bacteria that are present, allowing for further testing and identification. Never to forget the sputum is never sterile we have lot of flora which live with harmony of respiratory mucous membranes. That means that when a person has a bacterial respiratory infection, there will typically be harmless bacteria that are normally present in the mouth, throat, etc. as well as disease-causing (pathogenic) bacteria present. A trained laboratorian differentiates normal flora from pathogenic bacteria and identifies the various types of bacteria present in the culture. Identification is a step-by-step process that may involve several biochemical, immunological, and/or molecular tests and observations of the organism's growth characteristics. some fastidious organisms clearly seen on Gram stain may be overgrown by indigenous respiratory flora on solid media (e.g., Streptococcus pneumoniae). Many inexperienced microbiologists assume everything one sees or cultured can be interpreted as pathogen flow the misinformation to clinicians a true happening today with mushrooming of Microbiology laboratories without basic competence.
NEVER TO FORGET - Useful sputum culture results rely heavily on good sample collection. If examination of a Gram stain of the sample reveals that it contains a significant number of normal cells that line the mouth (squamous epithelial cells), then the sample is not generally considered adequate for culture and a re-collection of the sample may be required. If the sample contains most white blood cells / pus cells that indicate a body's response to an infection, then it is an adequate sample for culturing. (Refer 13 Edition Mackey McCartney Microbiology text Book)
SPUTUM CULTURING -Routine media used for the isolation and identification of respiratory pathogens include blood agar, chocolate agar, and MacConkey agar. Blood agar supports the growth of Gram positive cocci and most Gram-negative rods, and is especially useful for evaluation of the colony morphology and hemolysis of streptococci. Chocolate agar permits recovery of Haemophilus influenza. MacConkey agar is selective for Gram negative bacteria and allows further classification into lactose positive or negative organisms, based upon their ability to ferment lactose.
HOW WE COMMONLY REPORT - that a few colonies of a respiratory pathogen (e.g. Streptococcus pneumoniae, Haemophilus influenza, Moraxella catarrhalis) nestling among a mass of mixed upper respiratory tract flora is unlikely to be significant, but I am not aware of any literature that supports such an assertion. Clinicians don’t hang or bother around waiting for the patient to firstly produce a sputum sample, and then wait another 2 or 3 days whilst the microbiology laboratory processes it. They treat the patient empirically, according to guidelines that are hopefully formulated by laboratory data or with their own clinical experience outlining the expected pathogens and antibiograms in the local area. Only on rare occasions does a sputum culture result change patient management. So, we will continue to grapple with the vagaries of sputum culture, but I suspect it will be around for many years yet.
WE SHOULD THINK BEYOND THE CULTURE PLATE - For example, depending upon the clinical findings, additional tests for agents such as Mycoplasma pneumoniae, Bordetella pertussis, Legionella species, Aspergillus species, Typical Mycobacterium, atypical mycobacteria, respiratory syncytial virus, adenovirus, parainfluenza virus, influenza virus, and rhinovirus may be indicated. Which are more common causes in respiratory infections in the era where we have many immunosuppressed patients and misuse of antibiotics certainly give fallacious culture reports and sputum is no exception, Entire flora of the Respiratory system with doses of Antibiotics loses the value of bacterial culturing
IT IS TRUE HAPPENING THAT THE CLINICIAN EXHAUST ALL THE NEW GENERATION OF ANTIBIOTICS BEFORE OUR REPORTS REACH THE CLINICIANS?
Ref 1 Thresholds” May 8, 2017The Art of Microbiology sensitivity, specificity, sputum Michael @ Microbiology matters
2 Recent advances on culturing the clinical specimens from Web resources
Dr.T.V.Rao MD Freelance reporter on Clinical Microbiology in patient care
Dr.T.V.Rao MD A frequent specimen in our diagnostic laboratories is Sputum for Microscopy and culturing, we all have experienced many specimens sent as sputum are not sputum just saliva, nobody bothers to instruct the patients to send the better specimens, repeated instructions make no difference, many casually report and get rid of the matters, However to improve the matters Care must be taken in the sample collection process to ensure that the sample is from the lower airways and not from the upper respiratory tract. Sputum samples may be expectorated or induced I spoke on many occasion the greater failure of Microbiology lies with poor collection of specimens, clinicians too are not serious or wait for the reports, all the good efforts of microbiology go to files but not for utility. I always wonder so much human resource is wasted on many matters, from collecting the samples to processing with valuable media and chemicals, and at the end unfollowed results
HOW WE PROCESS THE SAMPLES Typically, the first step in the routine analysis of a sputum sample is a Gram stain to identify the general type of bacteria that may be present. The sample is then placed on or in appropriate nutrient media and incubated. The media encourages the growth of bacteria that are present, allowing for further testing and identification. Never to forget the sputum is never sterile we have lot of flora which live with harmony of respiratory mucous membranes. That means that when a person has a bacterial respiratory infection, there will typically be harmless bacteria that are normally present in the mouth, throat, etc. as well as disease-causing (pathogenic) bacteria present. A trained laboratorian differentiates normal flora from pathogenic bacteria and identifies the various types of bacteria present in the culture. Identification is a step-by-step process that may involve several biochemical, immunological, and/or molecular tests and observations of the organism's growth characteristics. some fastidious organisms clearly seen on Gram stain may be overgrown by indigenous respiratory flora on solid media (e.g., Streptococcus pneumoniae). Many inexperienced microbiologists assume everything one sees or cultured can be interpreted as pathogen flow the misinformation to clinicians a true happening today with mushrooming of Microbiology laboratories without basic competence.
NEVER TO FORGET - Useful sputum culture results rely heavily on good sample collection. If examination of a Gram stain of the sample reveals that it contains a significant number of normal cells that line the mouth (squamous epithelial cells), then the sample is not generally considered adequate for culture and a re-collection of the sample may be required. If the sample contains most white blood cells / pus cells that indicate a body's response to an infection, then it is an adequate sample for culturing. (Refer 13 Edition Mackey McCartney Microbiology text Book)
SPUTUM CULTURING -Routine media used for the isolation and identification of respiratory pathogens include blood agar, chocolate agar, and MacConkey agar. Blood agar supports the growth of Gram positive cocci and most Gram-negative rods, and is especially useful for evaluation of the colony morphology and hemolysis of streptococci. Chocolate agar permits recovery of Haemophilus influenza. MacConkey agar is selective for Gram negative bacteria and allows further classification into lactose positive or negative organisms, based upon their ability to ferment lactose.
HOW WE COMMONLY REPORT - that a few colonies of a respiratory pathogen (e.g. Streptococcus pneumoniae, Haemophilus influenza, Moraxella catarrhalis) nestling among a mass of mixed upper respiratory tract flora is unlikely to be significant, but I am not aware of any literature that supports such an assertion. Clinicians don’t hang or bother around waiting for the patient to firstly produce a sputum sample, and then wait another 2 or 3 days whilst the microbiology laboratory processes it. They treat the patient empirically, according to guidelines that are hopefully formulated by laboratory data or with their own clinical experience outlining the expected pathogens and antibiograms in the local area. Only on rare occasions does a sputum culture result change patient management. So, we will continue to grapple with the vagaries of sputum culture, but I suspect it will be around for many years yet.
WE SHOULD THINK BEYOND THE CULTURE PLATE - For example, depending upon the clinical findings, additional tests for agents such as Mycoplasma pneumoniae, Bordetella pertussis, Legionella species, Aspergillus species, Typical Mycobacterium, atypical mycobacteria, respiratory syncytial virus, adenovirus, parainfluenza virus, influenza virus, and rhinovirus may be indicated. Which are more common causes in respiratory infections in the era where we have many immunosuppressed patients and misuse of antibiotics certainly give fallacious culture reports and sputum is no exception, Entire flora of the Respiratory system with doses of Antibiotics loses the value of bacterial culturing
IT IS TRUE HAPPENING THAT THE CLINICIAN EXHAUST ALL THE NEW GENERATION OF ANTIBIOTICS BEFORE OUR REPORTS REACH THE CLINICIANS?
Ref 1 Thresholds” May 8, 2017The Art of Microbiology sensitivity, specificity, sputum Michael @ Microbiology matters
2 Recent advances on culturing the clinical specimens from Web resources
Dr.T.V.Rao MD Freelance reporter on Clinical Microbiology in patient care
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