Refrigeration slows other bacterial growth. Treating all organisms identified from respiratory tract cultures can lead to antibiotic overuse and encourage the development of antibiotic resistant organisms. It causes: Streptococci bacteria are also common pathogenic bacteria. Gram stain (right) is typical of the findings in viral pneumonia, showing many PMN and no bacteria. 2nd Ed. In a Gram stain test, these organisms yield a positive result. Learn how to spot and prevent anaplasmosis, a bacterial infection from the same ticks that spread Lyme disease. Most commonly represents colonization, but can cause isolated cases and outbreaks of symptomatic pharyngitis. The Author(s) 2020. What makes these seemingly normal bacteria so dangerous, and how can they live within humans and not cause disease most of the time, but occasionally cause lethal infections? Krzyściak W, et al. In addition, the peripheral WBC count was lower in pneumonia due to NRF. these two account for a very large percentage of what we see in pulmonary medicine. Can you please talk about of the common diseases for the respiratory system? Published by Oxford University Press on behalf of Infectious Diseases Society of America. B. cereus causes: About 30 Clostridia species cause disease in humans. We carried out a prospective study of a convenience sample of patients admitted to the Michael E. DeBakey VA Medical Center (MEDVAMC) between September 1, 2017 and April 30, 2019. We found that 13 of 68 (19.1%) patients infected with RBPs were coinfected with NRF, based on the presence of equal or higher numbers of NRF in their sputum, suggesting a pathogenic role for NRF in an even larger proportion of patients with CAP. The most common bacteria of the skin flora are the Gram-positive, catalase positive cocci of the genera Staphylococcus and Micrococcus. They will place a thin layer of your sputum on a slide and allow it to dry. Like all human skin and mucosal surfaces, the respiratory tract is colonized with commensal bacteria that protect the host from disease, increase epithelial cell renewal rates, and promote production of mucosal immunoglobulins. The World Health Organization (WHO) estimates that this organism is responsible for killing half a million children worldwide each year. Your doctor will use the scope to look into your lungs and collect a sample of your sputum to send to the lab for testing. If youre very sick, you may be in the hospital when your doctor orders a sputum Grams stain. <>>> These data imply that, in at least some cases, isolation of Gram-negative rods from sputum of untreated patients may be a normal finding, and that in some patients with pulmonary infection, the pretreatment, upper respiratory tract flora may serve as the source of subsequent superinfection with Gram-negative rods. Streptococcus pneumoniae was identified by screening for sensitivity to optochin and verified by bile solubility (if colony morphology was suspicious but the optochin test was negative, bile solubility was done anyway). Its an antibiotic that stops bacterial growth, and works against both gram-positive and gram-negative bacteria. Gram-positive bacteria dont have this feature. Patients with a positive viral PCR who met criteria for RBP or NRF pneumonia were regarded as having viral/bacterial coinfection. Washington, DC 20036, 2023. The bacteria and other microorganisms that normally inhabit a bodily organ or part: intestinal flora. To perform a bronchoscopy, your doctor or nurse will spray a local anesthetic into your nose and throat. Lack of normal flora also makes animals more susceptible to infection with a variety of pathogens, particularly those that infect the GI tract. Streptococcus mitis shares molecular characteristics of S pneumoniae, including the capacity to make capsule, and ample evidence shows their capacity to cause serious infection in humans [25, 32, 33]. endobj Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. (2013). <> These criteria were used to stratify pneumonia into 6 etiologic groups: pneumonia due to (1) RBPs; (2) respiratory viruses; (3) coinfection by RBPs and a respiratory virus; (4) NRF; (5) coinfection by NRF and a respiratory virus; and (6) cause undetermined. Recent studies using molecular techniques also have recognized multiple bacterial pathogens in high-quality sputum samples [6, 7, 36]. An etiology for CAP was identified in >95% of patients who provided a high-quality sputum at, or soon after, the time of admission. Patient was suspected to have intermittent aspiration. bIncludes 2 cases in which polymerase chain reaction (PCR) for influenza virus and respiratory syncytial virus were negative but the full viral respiratory PCR was not done. The flora of the mouth and upper respiratory tract is typically associated with a more diverse set of microbes. 2010. Review of Medical Microbiology and Immunology, 11e, Warren Levinson. For example, little to no growth might indicate something odd going on if you haven't been taking antibiotics. aureus is most often found in the nose of those individuals who carry it in their normal flora. Strep A, also known as group A strep, is a type of bacteria that causes strep throat and other infections. The fungal genus Candida is also common in the mouth and upper respiratory tract. The nostrils are always densely populated, mostly with Staphylococcus epidermidis and corynebacteria, and rarely (in about 20% of the general population) with Staphylococcus aureus. What is the most common respiratory viral illness? A respiratory virus alone was found in 16 of 120 (13.3%) patients. Each area of the human body contains a characteristic population of microbes (Figure \(\PageIndex{1}\)), although the exact composition of each persons flora is unique. Quantitative culture yielded 1.6107 Streptococcus pneumoniae per milliliter of sputum (right); the figure shows colony-forming units in 0.01-mL aliquots of sputum that had been diluted by 101 to 104 after an initial 1:2 dilution with 4% N-acetyl cysteine in 0.9% saline. (2018). (5) The median number of NRF per milliliter sputum in CAP patients (7106 per mL) was strikingly similar to that observed in patients with pneumonia due to RBP (8106). If pneumococci had been present in very small numbers in sputum, for example 105 per mL in the presence of 5106 S mitis, we might not have been able to detect them. This medicine works by targeting and removing toxins in the body. Organisms that are generally identified only as normal respiratory flora but met quantitative criteria (as defined below) were further studied by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF). It causes: S. saprophyticus, which is normally found in the genital tract and perineum. 1r`HpQ 8 y/#+-pDmqvOWsZc-|p.Vu=>exBQ'&M,?~L+TE {nZkP'Dowmskhwo1"K>x Heres why knowing whether. Under a microscope, gram-positive bacteria appear purple-blue because their thick peptidoglycan membrane can hold the dye. After adding the staining agent, the laboratory technician will examine the slide under a microscope. What does mixed flora, and many wbc's and few epithelial cells mean in a sputum culture? x=]sS5O))cA\5;L*{-6oeI+Q I(j@nZ?mjT'_n>owmWzl6Ul7?K~{0f2K2/K4O3._e#, ]rmnM(T! The present study, a single-center study with mainly male patients, was confined to patients who provided a high-quality expectorated sputum. If you log out, you will be required to enter your username and password the next time you visit. The test is sometimes called a Grams stain of sputum. They will give you a sterile sample cup to use. The remaining 39 (82%) patients with mixed flora received no antibiotic therapy and never developed pneumonia. The first introduction of microbiota to a human occurs at birth (a fetus in utero should be microbe-free). An additional 13 of 68 (19.1%) patients with RBP pneumonia had 1106 cfu of NRF per mL sputum (Figure 2E); although, in these cases, NRF may have contributed to infection, we followed convention by listing them in Tables 1, 2, and 4 as pneumonia due to RBP (see Discussion). Abbreviations: NRF, normal respiratory flora. Organisms that are generally identified only as "normal respiratory flora" but met quantitative criteria (as defined below) were further studied by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF). This removes secretions and oral plaque, which may contaminate the sample. Manual of Laboratory & Diagnostic Tests (7th Edition): Fischbach, Frances Talaska. Equipment: Sterile, leak-proof container. Gram stain (left) shows many polymorphonuclear leukocytes and Gram-positive cocci. Current perspectives on treatment of gram-positive infections in India: What is the way forward? (A) Pneumonia due to Streptococcus mitis (oralis). A sputum Grams stain is a laboratory test that allows your doctor to diagnose a bacterial infection in your respiratory tract. The antibiotic is mainly used for Streptococcus infections, including: Glycopeptide antibiotics are often used to treat serious infections caused by drug-resistant bacteria. They suggest that a Gram stain showing rare or no bacteria in a patient with a positive viral PCR who has not received antibiotics would justify withholding antibiotic therapy, a suggestion that opposes current guidelines [37]. 44 Suppl 2:S27-72. If the toxin causes an infection, its called tetanus. Enterobacteriaceae and nonfermenting gram-negative bacilli, Viridans group streptococci, nonhemolyic streptococci, coagulase-negative staphylococci, nonpathogenic Neisseria species, Corynebacterium species, Lactobacillus species, Micrococcus species, Stomatococcus speciesand Bacillus species. Keep coughing up sputum until the cup is filled to the marker, which should equal approximately 1 teaspoon. Staphylococcus aureus (Figure 1C) and Moraxella catarrhalis were detected alone or as coinfecting bacterial agents in 11 and 7 cases, respectively. Medscape Education, Challenging Case in Nontuberculous Mycobacterial Lung Disease: Going the Distance for Your Patient, 20021941994-overviewDiseases & Conditions, encoded search term (Sputum Culture) and Sputum Culture, Bacteria Causing Rare Disease Melioidosis Found in the United States, CLL Treatment: More Infections Among Real-World Patients, Bilateral Endogenous Bacterial Endophthalmitis. Symptoms depend on the specific. Depending on various traits, gram-positive bacteria are further classified into the following groups: Gram-positive cocci are circular or oval in shape. Like staphylococci, streptococci normally exist in the body. Z13.83 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. The bacteria is called gram-positive due to the positive result. DOI: Gillespie S, et al. If you have trouble, they may give you a breathing treatment to help loosen the sputum in your airways. (E) Coinfection by RBP and NRF. Top answers from doctors based on your search: Created for people with ongoing healthcare needs but benefits everyone. 1 0 obj This chemical dye can stain thick peptidoglycan layers. Normal flora can be found in many sites of the human body including the skin (especially the moist areas, such as the groin and between the toes), respiratory tract (particularly the nose), urinary tract . However, absent such a Gram stain, our findings support recommendations by the guidelines for empiric antibiotics for patients hospitalized for CAP even if a viral PCR is a positive because fully 60% of our patients with a positive viral PCR had bacterial coinfection. Although S. aureus can occasionally be found on the skin, it is more commonly found in the nose in those people that carry it in their normal flora. 'N,UZ&+}zu6/8O U"e?TL1&7@k(_fq XAeA@L`2wXrq`.t%ih0!Mnl$~#CiaE1+@D These include S. mutans, S. sanguis, and S. mitis. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Other pathogenic staphylococci are less common and rarely lead to disease. Pneumonia caused by pathogens that do not grow on standard sputum culture media (eg, atypical organisms, viruses, anaerobes). Boils are infections that cause a buildup of pus and dead skin cells within a, Healthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. It's standard culture protocol to include semi-quantitation as it could provide some clues for disease states. The sputum sample must come from deep inside your lungs for the test to be accurate. The novel finding in this study is that bacteria that are generally reported as NRF appears to play a causative role in 25.8% of cases of CAP. Bonten MJ, Huijts SM, Bolkenbaas M, et al. Heart of America Association of Blood Banks (HAABB), International Society of Blood Transfusion. Ogawa H, Kitsios GD, Iwata M, Terasawa T. Falsey AR, Becker KL, Swinburne AJ, et al. White blood cells per milliliter in liquefied sputum were counted in a hemocytometer. Gram stain result They are present either throughout the life of for short period of time. A sputum culture helps lab technicians find the bacteria or fungi that might be making you sick. Significance of these organisms in culture relies heavily on the clinical picture, other diagnostic testing and predominance in culture. colonization can lead to bacteremia, meningitis or septic arthritis. Cultures of Mycoplasma are infrequently done; diagnosis is usually confirmed by a rise in antibody titer. Other inhabitants of the mouth and upper respiratory tract include bacteria in the genera Neisseria and Haemophilus. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (. Normal respiratory flora caused CAP in 31 (25.8%) cases; 10 (32.3%) of these had viral coinfection. It should be noted on the requisition as being aerosol induced. A nurse will help you cough up sputum. West Sussex, UK: Wiley-Blackwell. Quantitative culture (data not shown ) yielded 2106 S aureus/mL. : From your description, it sounds like the diagnosis was normal flora present. normal respiratory flora include neisseria catarrhalis, candida albicans, diphtheroids, alpha-hemolytic streptococci, and some staphylococci. These gram-positive , sphere-shaped (coccal) bacteria (see figure How Bacteria Shape Up ) often cause skin infections but can cause pneumonia, heart valve infections, and bone infections and may be resistant to treatment with some antibiotics. In a sputum culture test, a laboratory uses a sample of this mucus to try to encourage the growth of any bacteria or other germs that may be causing an infection. Sputum is a mixture of saliva and mucus that you cough up from your respiratory tract. responsible for killing half a million children worldwide each year. Bacterial coinfection by 2 RBP or by RBP plus NRF was seen in 23 (19.2%) cases. The relationships between humans and bacteria are immensely complex. In a medical setting, a doctor can send a sample of your blood, urine, or tissue to a lab for Gram stain testing. Please check for further notifications by email. Quantitative culture (right) revealed 2.3107 Haemophilus influenzae and 5104 viridans streptococci (not further speciated). This website also contains material copyrighted by 3rd parties. For instance, a persons blood will become bacteremic (contain bacteria) for up to three hours after brushing their teeth. Infants born by caesarean section have significantly different microbiota than those born vaginally. Serious respiratory infections are a risk for all hospitalized patients, but are particularly common in the intensive care unit (ICU). (2012). Normal respiratory microbiota can play a key role in human health, but can also play a part in severe respiratory disease. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America, The lung microbiome: new principles for respiratory bacteriology in health and disease. One-milliliter micropipetters, with the tips cut to enlarge the orifice, were used to draw up 0.51 mL purulent sputum that was then liquefied with 2% N-acetyl cysteine and diluted serially; 0.01 mL aliquots were streaked onto blood and chocolate agar and incubated under 5% CO2. ; GRACE consortium. Kilian M, Riley DR, Jensen A, et al. Gram stain shows large numbers of yeast, many of which appear to be intracellular, and some Gram-positive cocci. Is respiratory allergy one of the many reasons that can cause mild chest discomfort? An infants diet also has a substantial effect on the establishment of a healthy microbiota. We avoid using tertiary references. White blood cells per milliliter in liquefied sputum were counted in a hemocytometer. Delmars Guide to Laboratory and Diagnostic Tests. <> Bacterial coinfection was present in 24 of 40 (60%) cases with viral detection: 14 cases with RBP and 10 with NRF. In diagnosing aspiration pneumonia and lung abscesses, anaerobic cultures are important. Gram-positive bacilli are further categorized based on their ability to make spores. These specimens are not easily collected without introducing contamination from adjacent areas. (2016). For these, please consult a doctor (virtually or in person). Fukuyama H, Yamashiro S, Kinjo K, et al. Normal respiratory flora include Neisseria catarrhalis, Candida albicans, diphtheroids, alpha-hemolytic streptococci, and some staphylococci. Nonetheless, a pathogenic role for NRF, including S mitis [25] and Rothia [26], has been demonstrated. To minimize selection bias, on each day selected for study, we included every patient who met inclusion criteria. There tends to be more bacteria present at this time and can help ensure accurate test results. HealthTap uses cookies to enhance your site experience and for analytics and advertising purposes. Normal floras are the microorganisms present in the skin and mucous membrane of every human in a relatively stable manner without causing any disease/infection in a healthy individual. Not surprisingly, NRF appeared to be less virulent than RBPs. If you have a bacterial lung infection, they will likely prescribe antibiotics. This means gram-positive and gram-negative bacteria require different treatments. Categorical values were compared using Fishers exact test. Sizar O, et al. (2014). Though gram-negative bacteria are harder to destroy, gram-positive bacteria can still cause problems. To complete a sputum Grams stain, your doctor will need to a collect a sample of your sputum and send it to a laboratory for testing. This resident flora produces antigens that . Median colony-forming units per milliliter for S pneumoniae, H influenzae, M catarrhalis, and S aureus were 2106, 4106, 7107, and 3106, respectively, and, after final review, Gram stain results were consistent with quantitative bacterial cultures in all but 4 of 68 (5.9%) cases. Quantitative sputum culture showed 2107 C glabrata and 2105 viridans streptococci per mL. Pediatr Neonatol. Recognized bacterial pathogens were identified by standard microbiologic techniques. C. difficile causes: C. tetani spores produce the tetanus toxin, a neurotoxic substance. Your doctor may ask you to collect a sample of your own sputum, but if you cant they may collect one using a bronchoscopy. Of patients with RBP pneumonia, sputum from 14.7% had 2 RBPs. Best to see an allergist to determine the cause and to help you prevent complications e.g. Certain Clinical Features Related to Etiology. Throughout a persons lifetime a variety of factors can influence the composition of their microbiota including diet, environmental factors, and genetics. In fact, pneumonia is the second most common nosocomial infection affecting critically ill patients in the ICU. This test can determine if you have TB or another infection. There is some evidence that children who are not exposed to a variety of microbes early in life or frequently take antibiotics display the effects of an altered microbiome later on such as allergies, metabolic disorders and obesity, and possibly even certain mental disorders. The following factors show that this is not the case and support the validity of our results. Avoids contamination of the sample. %Tyk Organisms that normally live within the respiratory tract may end up being the same organisms that cause pneumonia in these patients. In terms of predicting gram-negative bacilli, gram-negative cocci, and gram-positive cocci, sputum Gram stains had specificities of 0.87, 0.98, and 0.87, respectively. Are organisms present simply colonizing the endotracheal tube and surrounding airway without causing harm, or are they the cause of infection? endobj Gleckman R, DeVita J, Hibert D, et al. This difference in the rate of viral coinfection was not significant (P=.26). Plain saliva comes from your mouth and is usually clear. 63. The following organisms are the most prevalent. You can do this by boiling water and cooking food to the correct, Moraxella catarrhalis is a type of bacteria that can cause infections in children as well as adults who have weakened immune systems. Majd Ibrahim, MD Chief Medical Resident, Department of Internal Medicine, University of Illinois College of Medicine at Peoria As mentioned above, Staph. They might also give you a sedative to help you relax, or medication to put you to sleep, but general anesthesia isnt required. Collect the expectorated sputum in a leak-proof sterile container. Your doctor may also ask you to avoid eating and drinking anything the night before your procedure. Write your name and the date on the label. The present study applied quantitative microbiologic methods in a prospective study of patients hospitalized for CAP who were able to provide a high-quality expectorated sputum at the time of, or soon after, admission to examine the potential etiologic role of NRF in pneumonia. You can learn more about how we ensure our content is accurate and current by reading our. This will probably be enough to treat your infection if you have a healthy immune system. Theyre typically found in the skin, mouth, intestinal tract, and genital tract. If you have an infection or chronic illness affecting the lungs or airways, it can make you cough up sputum . Daniel M Musher, Sirus J Jesudasen, Joseph W Barwatt, Daniel N Cohen, Benjamin J Moss, Maria C Rodriguez-Barradas, Normal Respiratory Flora as a Cause of Community-Acquired Pneumonia, Open Forum Infectious Diseases, Volume 7, Issue 9, September 2020, ofaa307, https://doi.org/10.1093/ofid/ofaa307. On days selected for study, Gram stains of all sputum samples that had been submitted to the clinical microbiology laboratory in the preceding 24 hours were examined. They may order it if you have symptoms of a respiratory infection that might be caused by bacteria. Cough, dyspnea, wheezing, chest tightness, chest heaviness, chest pain, gasping, snoring, stridor, sputum production, heartburn, hemoptysis, fever, ca ) It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide, This PDF is available to Subscribers Only. Its responsible for most staphylococci infections, including: Often, S. epidermis causes infections in people with weakened immune systems or who are in the hospital. BSC 3271: Microbiology for Health Sciences Sp21 (Kagle), { "13.01:_Normal_Flora_of_the_Human_Body" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "13.02:_The_Role_of_Microbiota_in_Human_Physiology" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "13.03:_Pathogens_in_the_Normal_Flora" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "13.04:_Probiotics_and_Prebiotics" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, { "00:_Front_Matter" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "01:_Introduction" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "02:_Microbial_Structure" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "03:_Viruses" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "04:_Microbial_Diversity" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "05:_Principles_of_Microbial_Metabolism" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "06:_Fueling_and_Building_Cells" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "07:_Growth" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "08:_DNA_Replication" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "09:_Antimicrobial_Drugs" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "10:_Bacterial_Genetics" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "11:_Bacterial_Communities" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "12:_How_Microbes_Cause_Disease" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "13:_The_Human_Microbiota" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "14:_Immunology" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "15:_Selected_Pathogens" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "zz:_Back_Matter" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, https://bio.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fbio.libretexts.org%2FCourses%2FMansfield_University_of_Pennsylvania%2FBSC_3271%253A_Microbiology_for_Health_Sciences_Sp21_(Kagle)%2F13%253A_The_Human_Microbiota%2F13.01%253A_Normal_Flora_of_the_Human_Body, \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\), 13.2: The Role of Microbiota in Human Physiology, Flora of the Mouth and Upper Respiratory Tract.