systemic_group_3.lstystemic bacteriology

Micro

1. Group 3 Group 3 members: SHBI/01112/2019 ACHIENG TERRY SHBI/01094/2017 OTIENO JULIUS SHBI/01086/2019 ALFRED NJIMA SHBI/00624/2017 VICTOR JOASH SHBI/01524/2018 SOLVAY MOKAYA SHBI/01102/2019 KIBET COLLINS SHBI/01118/2019 MONICAH OMONDI SHBI/01119/2019 APONDI COLLINS

2. Legionella

3. Legionella Legionella pneumophila (and other legionellae) causes pneumonia, both in the community and in hospitalized immunocompromised patients. Important Properties Legionellae are gram-negative rods that stain faintly with the standard Gram stain. They do, however, have a gram-negative type of cell wall, and increasing the time of the safranin counterstain enhances visibility. Legionella pneumophila causes approximately 90% of pneumonia attributed to legionellae. There are 16 serogroups of L. pneumophila , with most cases caused by serogroup organisms.

4. Classification

5. Morphology Gram-negative, rigid Shape : Legionella bacteria are typically rod-shaped (bacillus) and are often described as being thin and elongated.Highly motile-single polar flagella Size : Legionella bacteria are relatively small, with an average size of about 2-5 micrometers in length and around 0.2-0.5 micrometers in width. Motility : Legionella bacteria are usually motile, possessing a single polar flagellum or multiple flagella that enable them to move in water environments Capsule : Some strains of Legionella may possess a capsule

6. Cultural Characteristics Selective Media :Buffered charcoal yeast extract (BCYE) agar is a commonly used medium. BCYE agar contains nutrients such as yeast extract, amino acids, and iron salts that support the growth of Legionella. L-Cysteine and Iron : Legionella species need L-cysteine (an amino acid) and iron for proper growth. Temperature : Legionella species are mesophilic, meaning they thrive at moderate temperatures. The optimal temperature for their growth is around 35-37°C (95-99°F Colonies : Legionella colonies on BCYE agar are often grayish-white to cream-colored, round, convex, and translucent.

7. Cultural Characteristics Incubation Period : Culturing Legionella species can take some time due to their slow growth rate. Plates are typically incubated for about 3-7 days before being examined for bacterial colonies. Hemolysis : Some species of Legionella might exhibit hemolysis (breaking down of red blood cells) when grown on blood agar, but this is not a consistent characteristic among all Legionella species. Nutritional Requirements : In addition to L-cysteine and iron, Legionella species have specific nutritional requirements for amino acids, vitamins, and other compounds. Growth media are formulated to meet these needs.

8. Biochemical Characteristics Catalase positive Oxidase positive Urease Negative Nitrate reduction Utilization of Amino acids Utilization of carbohydrates Esculin hydrolysis Indole production – Negative for indole production

9. Pathogenesis And Epidemiology Legionellae are associated chiefly with environmental water sources such as air conditioners and water-cooling towers. Outbreaks of pneumonia in hospitals have been attributed to the presence of the organism in water taps, sinks, and showers Legionellae can replicate to large numbers in free-living amebas in these water sources. The typical canadidate for Legionnaires’ disease is an older man who smokes and consumes substantial amounts of alcohol. Patients with acquired immunodeficiency syndrome (AIDS), cancer , or transplants (especially renal transplants) or patients being treated with corticosteroids are predisposed to Legionella pneumonia

10. Virulence factors Flagella and motility : Type IV Secretion System (T4SS): Legionella species possess a sophisticated type IV secretion system, which allows them to inject effector proteins into host cells. Intracellular Replication : Legionella species have evolved to replicate within host cells, primarily within phagocytes like macrophages LPS Modifications : Legionella species have lipopolysaccharides (LPS) on their outer membrane, but the structure is modified compared to other Gram-negative bacteria Iron Acquisition : Legionella species have evolved mechanisms to scavenge iron from the host environment. This contributes to their ability to replicate within host cells and evade immune responses.

11. Virulence factors Evasion of Phagosome-Lysosome Fusion : Legionella bacteria are able to avoid being degraded within phagolysosomes by inhibiting phagosome-lysosome fusion Phospholipase C : Some Legionella species produce phospholipase C, an enzyme that hydrolyzes host cell membranes, allowing the bacteria to escape from the phagosome and enter the host cell cytoplasm Biofilm Formation : In aquatic environments, Legionella can form biofilms on surfaces, providing protection from disinfection measures and allowing the bacteria to persist and multiply

12. Laboratory Diagnosis Sample Collection: Respiratory samples, such as sputum, bronchoalveolar lavage (BAL), or tracheal aspirates, are commonly collected from patients suspected of having Legionella infections. Urine samples can also be tested for specific antigens Sputum Gram stains reveal many neutrophils but no bacteria. The organism fails to grow on ordinary media in a culture of sputum or blood , but it will grow on charcoal yeast agar, a special medium supplemented with iron and cysteine. Polymerase Chain Reaction (PCR ): PCR can amplify specific DNA sequences of Legionella bacteria in clinical samples. It offers high sensitivity and specificity and can provide rapid results

13. Laboratory Diagnosis Urinary Antigen Testing : Legionella pneumophila serogroup 1 is the most common cause of Legionnaires' disease, and a urinary antigen test specific to this serogroup can provide rapid diagnosis. Serological Testing : Serological tests measure antibody responses against Legionella antigens in patient serum. A rise in antibody titers between acute and convalescent samples can suggest a recent infection. Next-Generation Sequencing (NGS): NGS techniques, such as whole-genome sequencing (WGS), can provide detailed genetic information about Legionella isolates.

14. Clinical Findings The clinical picture can vary from a mild influenza like illness to a severe pneumonia accompanied by mental confusion, nonbloody diarrhea, proteinuria, and microscopic hematuria.

15. Treatment Azithromycin or erythromycin (with or without rifampin) is the treatment of choice. Certain fluoroquinolones, such as levofloxacin and trovafloxacin, are also drugs of choice. These drugs are effective not only against L. pneumophila , but also against Mycoplasma pneumoniae and Streptococcus pneumoniae . The organism frequently produces β-lactamase, and so penicillins and cephalosporins are less effective.

16. Prevention Prevention involves reducing cigarette and alcohol consumption, eliminating aerosols from water sources, and reducing the incidence of Legionella in hospital water supplies by using high temperatures and hyperchlorination. There is no vaccine.

17. Moraxella

18. Moraxella Moraxella is a genus of bacteria that belong to the family Moraxellaceae . They are Gram-negative, aerobic, non-motile cocci or coccobacilli. Moraxella species are commonly found in various environments, including the human respiratory tract and other mucous membranes, as well as in soil and water. Some species of Moraxella are considered opportunistic pathogens and can cause infections in humans, especially in immunocompromised individuals or those with underlying health conditions

19. Classification Domain: Bacteria Phylum: Proteobacteria Class: Gammaproteobacteria Order: Pseudomonadales Family: Moraxellaceae Genus: Moraxella . This genus includes the species, Moraxella catarrhalis , M. oblonga, M. osloensis , M. saccharolytica , M. phenylpyruvica , M. lacunata , M. lincolnii , M. nonliquefaciens , M. boevrei , M . bovis , M. canis , M. caprae , M. caviae , M. cuniculi, and M. equi . Of these species , Moraxella catarrhalis, M. lacunata , M. nonliquefaciens , M. osloensis , M. atlantae , and M. phenylpyruvica are the most clinically significant. Animal-specific strains include M. bovis , M. canis , and M. caprae .

20. Morphology Shape: Generally coccobacilli (oval or elongated cocci). Cell Arrangement: Can occur singly, in pairs, or short chains. Size: Small, around 1-2 micrometers in diameter Cell Wall: Gram-negative, with an outer membrane containing lipopolysaccharides (LPS). Capsule: Some species possess a capsule that surrounds the cell, aiding in virulence and protection. Spores: Non-sporulating; does not form endospores Non motile

21. Cultural Characteristics Colonies on Agar: Moraxella colonies are often small, smooth, and translucent. They can appear whitish or slightly yellowish. Growth Rate: Moraxella species tend to have a slow growth rate compared to many other bacteria Nutritional Requirements: Moraxella are often considered fastidious bacteria, meaning they have specific nutritional requirements and may require enriched media or supplements to grow well. Media Preference: Blood agar and chocolate agar are commonly used media to culture Moraxella due to their nutritional richness. The blood components in these media provide essential growth factors

22. Cultural Characteristics

23. Biochemical characteristics Gram-negative: Oxidase-positive: Catalase-positive: Non-motile:. Non-fermentative:. Indole-negative: . Glucose utilization: Nitrate reduction: Urease-negative:

24. Pathogenesis Transmission : Moraxella bacteria are typically transmitted from person to person through respiratory droplets when an infected person coughs or sneezes. It can also spread by direct contact with infected individuals or contaminated surfaces. Attachment : Once the bacteria enter the respiratory tract of a susceptible individual, they use their surface structures, like pili and adhesins, to attach to the mucosal surfaces of the respiratory tract, particularly the epithelial cells lining the airways and nasal passages. Colonization : After attaching to the respiratory epithelial cells, Moraxella bacteria start to multiply and form colonies, establishing themselves in the host's respiratory tract.

25. Pathogenesis Invasion and Damage : Moraxella catarrhalis can produce various virulence factors, such as outer membrane proteins and toxins, which help them evade the host's immune system and cause damage to the respiratory tissues. These factors contribute to the inflammation of the respiratory tract, leading to the characteristic symptoms of respiratory infections. Immune Response: In response to the bacterial invasion, the host's immune system activates various defense mechanisms, including the recruitment of immune cells to the infected site, release of inflammatory mediators, and the production of specific antibodies. However, Moraxella bacteria have developed mechanisms to evade and resist these immune responses, allowing them to persist and cause chronic infections in some cases.

26. Virulence factors Capsule: Some Moraxella species have a capsule that helps them evade the host's immune system by preventing phagocytosis Pili/Fimbriae: Pili are hair-like structures on the bacterial surface that facilitate adherence to host cells and surfaces IgA Protease: Some Moraxella species produce IgA protease enzymes that can cleave and degrade immunoglobulin A (IgA), an antibody class important in mucosal immunity Toxins: Certain Moraxella species can produce toxins that contribute to tissue damage and inflammation

27. Virulence factors Lipopolysaccharides (LPS): The outer membrane of Moraxella bacteria contains LPS, which can trigger inflammatory responses in the host Adhesins: Apart from pili, other adhesins on the bacterial surface facilitate binding to specific host cell receptors, enabling the bacteria to colonize and establish infections Outer Membrane Proteins: Outer membrane proteins, including porins, can contribute to the virulence of Moraxella species by aiding in nutrient uptake, facilitating bacterial adhesion, and interacting with host immune responses.

28. Laboratory Diagnosis Sample Collection: Obtain a clinical sample from the site of infection, which could include sputum, conjunctival swabs, wound swabs, or other relevant specimens. Transport and Storage: Properly transport the sample to the laboratory using appropriate transport media to maintain the viability of the bacteria during transit. Microscopic Examination: Perform Gram staining of the sample to observe the morphology and Gram reaction of the bacteria. Moraxella species are Gram-negative cocci or coccobacilli. Culture: Inoculate the sample onto appropriate culture media. Chocolate agar or blood agar are commonly used, as they provide the necessary nutrients for the growth of Moraxella species.

29. Laboratory Diagnosis Incubation: Incubate the cultures at the appropriate temperature (usually around 35-37°C) and atmospheric conditions (usually aerobic). Isolation: After incubation, examine the cultures for colony growth. Moraxella colonies are typically small, smooth, translucent, and often have a whitish or yellowish appearance. Gram Stain of Colonies: Perform Gram staining on isolated colonies to confirm their Gram-negative nature and verify their morphology. Biochemical Tests: Perform various biochemical tests to confirm the identity of the isolated bacteria as Moraxella. These tests may include oxidase test (positive for Moraxella), catalase test (positive), and other relevant metabolic tests.

30. Laboratory Diagnosis Antibiotic Sensitivity Testing: If the identified Moraxella isolate is from a clinical specimen, antibiotic sensitivity testing should be performed to guide appropriate treatment. Serological Tests: In some cases, serological tests may be used to detect specific antibodies against Moraxella species in patient serum. Molecular Methods: Polymerase Chain Reaction (PCR) assays targeting specific Moraxella genes can provide rapid and accurate identification of the bacteria.

31. Clinical Findings Respiratory Tract Infections: Acute Exacerbation of Chronic Bronchitis: Moraxella catarrhalis is a common cause of exacerbations in chronic bronchitis patients, leading to increased cough, sputum production, and shortness of breath. Sinusitis: Moraxella species can contribute to sinus infections, causing symptoms like facial pain, congestion, and headache. Conjunctivitis (Pink Eye): Bacterial Conjunctivitis: Moraxella can cause bacterial conjunctivitis, resulting in redness, irritation, discharge, and sometimes crusty eyelids. Wound Infections: Skin and Soft Tissue Infections: Moraxella species can lead to localized skin infections, maanifesting as redness, swelling, pain, and sometimes the formation of pustules or abscesses. Otitis Media: Ear Infections: Moraxella catarrhalis can be a causative agent of otitis media (ear infections), causing ear pain, fluid buildup, and hearing difficulties, especially in children. Pneumonia: Community-Acquired Pneumonia: In some cases, Moraxella species can contribute to community-acquired pneumonia, with symptoms like fever, cough, chest pain, and difficulty breathing

32. Treatment Antibiotics: Moraxella infections are typically treated with antibiotics. Commonly used antibiotics include beta-lactams (such as amoxicillin-clavulanate), cephalosporins (such as ceftriaxone), and macrolides (such as azithromycin). However, antibiotic choice should be based on the specific species and its antibiotic susceptibility profile. Antibiotic Sensitivity Testing: It's important to perform antibiotic sensitivity testing on the isolated bacteria to determine which antibiotics are effective against the specific strain. This helps in guiding appropriate treatment. Duration of Treatment: The duration of antibiotic treatment varies depending on the type and severity of the infection. Treatment for respiratory tract infections, for example, might last for 7-14 days. Follow-Up: Patients should complete the full course of antibiotics as prescribed by the healthcare provider, even if symptoms improve before the course is finished

33. Prevention Hygiene and Handwashing: Practicing good hygiene, including frequent handwashing, can help prevent the spread of Moraxella bacteria and other pathogens. Vaccination: For Moraxella catarrhalis, there is ongoing research into developing vaccines, especially for conditions like otitis media and pneumonia. Vaccination could potentially reduce the incidence of infections caused by this bacterium. Avoiding Close Contact: In cases of contagious infections like conjunctivitis, avoiding close contact with infected individuals can help prevent the spread of the bacteria. Respiratory Etiquette: Practicing respiratory etiquette, such as covering the mouth and nose when coughing or sneezing, can reduce the transmission of respiratory infections. Infection Control: In healthcare settings, implementing infection control measures, including proper sterilization of equipment and adherence to hand hygiene protocols, is crucial to prevent the spread of Moraxella infections.

34. PSEUDOMONAS

35. PSEUDOMONAS Pseudomonads are gram-negative and nonfermentative bacilli that are widely distributed in nature as saprophytes or as commensals and pathogens for man. Gessard in 1882 isolated Pseudomonas aeruginosa. More than 100 species of Pseudomonads have been isolated so far. The most frequently encountered species of Pseudomonas in humans is P. aeruginosa. This is a classical opportunist pathogen with innate resistance to many antibiotics and disinfectants. It is invasive and toxigenic, produces infections in patients with abnormal host defences and is an important nosocomial pathogen

36. Classification Domain: Bacteria Phylum: Proteobacteria Class: Gammaproteobacteria Order: Pseudomonadales Family: Pseudomonadaceae Genus: Pseudomonas Pseudomonas  is a  genus   belonging to the family  Pseudomonadaceae  in the class  Gammaproteobacteria . This genus includes many species of bacteria, the most important of which include: P. aeruginosa , P . alcaligenes , P . fluorescen,P . mendocina , P . putida , P . stutzeri

37. Morphology P.aeruginosa strains are gram-negative bacilli with variable length. These measure 1.5-3.0 μm × 0.5 μm . These have parallel sides and rounded ends and are arranged singly, in small bundles or short chains. The organism is motile with monotrichate flagellum. The cell wall and other structural components are similar to other Gram negative bacilli. Fimbriae present on P.aeruginosa differ from those on other gram-negative bacilli in their inability to cause haemagglutination .

38. Cultural Characteristics P.aeruginosa is capable of growing in a wide range of temperature but optimal growth occurs at 28°C. This organism can grow even at 41°C. pH below 4.5 is not conducive for its growth. It is an obligatory anaerobic species. Clinical isolates grown on blood agar are frequently haemolytic On nutrient agar P.aeruginosa can produce three types of colonies which are 2-3 mm in diameter with a matt surface, a floccular internal structure and butyrous consistency. Strains which are isolated from cases of cystic fibrosis are mucoid in nature and produce copious amounts of extracellular polysaccharide on nutrient agar

39. Pigmentation on media Four types of pigments can be produced by P.aeruginosa strains. Pyocyanin: It is a bluish -green phenazine pigment soluble in water and chloroform. P. aeruginosa only produces this pigment, therefore this is a diagnostic property of this bacterium. Pyoverdin:This pigment is a greenish yellow soluble in water but insoluble in chloroform. other species can also produce this pigment. Pyorubin:This pigment is a reddish brown that is soluble in water and insoluble in chloroform. Pyomelanin : It is a brown to black pigment. It is chemically unrelated to melanin and its production is uncommon.

40. Biochemical Characteristics They are oxidative and non- fermentative. Glucose is utilized oxidatively. Indole, Methyl Red (MR) and VogesProskauer (VP) and hydrogen sulphide (H2S) tests are negative. Catalase, oxidase, and arginine tests are positive.

41. Virulence Factors Pseudomonas aeruginosa has a number of virulence factors including: Pili or fimbriae which mediate adherence to respiratory epithelium. Polysaccharide capsule which covered the bacterial surface to protect it from phagocytosis. Lipopolysaccharide endotoxin as a major cell antigen mediates the various biological effects such as fever, shock, oliguria and leucopenia. Exotoxin A and exotoxin S which blocks or inhibition protein synthesis. Elastase enzyme which destruction of the elastic fiber in blood vessel walls, resulting in hemorrhagic lesions Protease enzyme that mediate tissue destruction, inactivation of antibiotics and inhibition of neutrophils function. Phospholipids C that break down lipids and tissue destruction.

42. Pathogenesis and clinical picture Several exotoxins and enzymes produced by P.aeruginosa along with endotoxic cell wall and fimbriae as well as occasionally a mucoid capsule probably account for the virulence associated with this organism. The organism is so ubiquitous in wet hospital environment that some people prefer to call it as water bug. In a hospital setting no open wound, burn or immunologically deficient patient is free from exposure. The major body defence against Pseudomonas infection appears to be functioning phagocytic system. In any condition which causes leukopenia, Pseudomonas assumes an opportunistic pathogenic role. Several clinical conditions which are highly correlated with P.aeruginosa infection include cystic fibrosis, burns, urinary catheterization, lumbar puncture and cancer chemotherapy. From any such condition the patient may develop Pseudomonas pneumonia or bacteraemia

43. Pathogenicity of Pseudomonas They cause blue pus, causing the nosocomial infection, suppurative otitis, localised and generalised infections, Urinary tract infection (UTI) after catheterization, iIatrogenic meningitis, post tracheostomy pulmonary infections etc. This bacterium is of particular concern to individuals with cystic fibrosis who are highly susceptible to Pseudomonas lung infections. It is also of grave concern to cancer and burn patients as well as those people who are immuno-compromised.

44. Laboratory Diagnosis Diagnosis of P. aeroginosa infection depends upon isolation and laboratory identification of the bacterium. It grows well on most laboratory media and commonly is isolated on blood agar or eosin-methylthionine blue agar. It is identified on the basis of its Gram morphology, inability to ferment lactose, a positive oxidase reaction, its fruity odour , and its ability to grow at 42°C. Fluorescence under ultraviolet light is helpful in early identification of P. aeruginosa colonies. Fluorescence is also used to suggest the presence of P. aeruginosa in wounds

45. Treatment of P. aeruginosa The method of treatment employed by the clinicians depends on the severity of the infection. In the case of mild infections, courses of IV antibiotics are adequate enough for treatment; however, under deeper infections, surgical debridement might also be required. In patients with respiratory failure, pneumonia, sepsis, or other systemic infections, ICU admissions might be necessary. In addition to the broad-spectrum antibiotics, double pseudomonal coverage might also be needed. Common antibiotics that are used as first-line therapy include carbapenems, cephalosporins, aminoglycosides, and fluoroquinolones. In the case of systemic infections, longer exposure to medicinal therapy might be required. In infections caused by medical devices like catheters, removal of such devices is done

46. Prevention and control Effective infection control practices should concentrate on prevention of contamination of sterile equipment such as respiratory therapy machines and cross - contamination of patients by medical personnel. The inappropriate use of broad spectrum antibiotics should be avoided because this can suppress the normal flora and permit the over growth of resistant Pseudomonas. Several types of vaccines are being tested, but none is currently available for general use.

47. PASTEURELLA

48. Classification Domain: Bacteria Phylum: Proteobacteria Class: Gammaproteobacteria Order: Pasteurellales Family: Pasteurellaceae Genus: Pasteurella

49. Classification Pasteurella belongs to the Pasteurellaceae family, which also includes the genera Haemophilus and Actinobacillus . P. aerogenes, P. avium, P. bettyae , P. canis , P. dagmatis , P. gallinarum , P. multocida , P. pneumotropica , P. stomatis , P. testudinis , P. trehalosi , and P. volantium are the current species of Pasteurella . P. multocida , P. canis , P. stomatis , and P. dagmatis are the most frequent species in human infections. P. multocida has three subspecies : P. multocida subsp. gallicida , P. multocida subsp. multocida , and P. multocida subsp. septica . Furthermore, P. multocida strains are classified into serogroups A, B, D, E, and F based on capsule antigenicity and serotypes 1–16 based on lipopolysaccharide antigens.

50. Morphology Shape: Small, Gram-negative rods (bacilli). Arrangement: Usually appear singly or in pairs. Size: Generally, 0.3-0.5 μm in width and 1-2 μm in length. Cell Wall: Possesses a thin peptidoglycan layer in the cell wall, which contributes to its Gram-negative staining. Capsule: Some strains may produce a capsule, contributing to virulence and immune evasion. Motility: Non-motile. Spores: Non-spore forming. Flagella: Generally lack flagella, but some strains might have polar flagella for limited motility.

51. Cultural characteristics Media: Pasteurella species are often grown on specialized media that provide the necessary nutrients for their fastidious growth requirements. Colonies: Colonies on agar plates are typically small, smooth, and translucent or slightly opaque. The appearance can vary depending on the species and strain. Hemolysis: Pasteurella species are generally non-hemolytic on blood agar, meaning they do not cause complete destruction of red blood cells in the agar medium.

52. Cultural characteristics Oxygen Requirements: These bacteria are facultative anaerobes, meaning they can grow both in the presence and absence of oxygen. However, they generally prefer environments with lower oxygen levels. Temperature: Optimal growth temperature can vary among species, but they typically grow best at temperatures around 37°C (98.6°F), which is close to the body temperature of their host animals. pH Range: The pH range for growth can vary, but it generally falls within the neutral to slightly alkaline range. Selective Media: Due to their fastidious nature, Pasteurella species may require selective media that provide specific nutrients to promote their growth while inhibiting the growth of other organisms.

53. Biochemical characteristics Catalase and oxidase positive They do not ferment lactose Indole production ,Nitrate reduction, urease production and citrate utilization is variable They are able to ferment glucose Hydrogen sulfide production, Gelatin Hydrolysis and Esculin hydrolysis is variable

54. Virulence factors Capsule: helps the bacteria evade phagocytosis by host immune cells, making it more difficult for the immune system to recognize and attack the bacteria Lipopolysaccharides (LPS): initiate immune responses. Exotoxins: Some Pasteurella species produce exotoxins that can damage host cells and tissues. Adhesins: Adhesins are surface molecules that allow Pasteurella bacteria to bind to host cells and tissues Iron Uptake Mechanisms: Pasteurella species have mechanisms to acquire iron from the host's environment

55. Virulence factors Hemolysins: While Pasteurella species are generally non-hemolytic on blood agar, they can produce hemolysins that can damage host red blood cells and contribute to tissue damage Resistance to Host Defense Mechanisms: Pasteurella species have evolved mechanisms to resist host defense mechanisms, such as phagocytosis by immune cells. Antigenic Variation: Pasteurella bacteria can undergo antigenic variation, where they alter their surface antigens to evade host immune responses

56. Pathogenesis Transmission : Pasteurella bacteria typically reside in the respiratory tracts of various animals, including cats, dogs, rabbits, and birds. Entry and colonization: Pasteurella can enter the human body through breaks in the skin, such as wounds or animal bites Local infection : Once Pasteurella establishes itself at the site of entry, it can cause localized infections such as cellulitis, abscesses, or wound infections. The affected area may become red, swollen, and painful Systemic spread: In some cases, Pasteurella infections can progress to more severe systemic infections, especially in individuals with compromised immune systems. Bacteria can enter the bloodstream and spread to other parts of the body, leading to conditions like septicemia (bloodstream infection) or osteomyelitis (bone infection). Immune response: The human immune system responds to the presence of Pasteurella by activating various defense mechanisms, including the recruitment of immune cells to the infected area.

57. Clinical Features of Pasteurella Skin and Soft Tissue Infections Commonly seen after animal bites or scratches. Rapid onset of redness, swelling, warmth, and pain at the site. May progress to localized abscess formation. Cellulitis Infection spreads through the skin's deeper layers. Skin becomes tender, swollen, and may have a " peau d'orange " appearance. Fever and malaise can accompany severe cases.

58. Clinical Features of Pasteurella Abscess Formation Accumulation of pus due to localized bacterial growth. Presents as a swollen, fluctuant, tender mass. May require surgical drainage for resolution. Systemic Infections Bacteremia: Presence of bacteria in the bloodstream. Can lead to fever, chills, rapid heartbeat, and hypotension. Potentially life-threatening if not treated promptly.

59. Clinical Features of Pasteurella Respiratory Tract Infections Seen in animals, less commonly in humans. Cough, nasal discharge, sneezing, and difficulty breathing. Pneumonia or bronchopneumonia can develop. Osteomyelitis Infection of the bone, often due to direct inoculation. Presents with bone pain, swelling, and limited mobility. More common in cases of deep puncture wounds.

60. Clinical Features of Pasteurella Septic Arthritis Infection of a joint, causing pain, swelling, and reduced range of motion. Often occurs following joint injury or surgery. Endocarditis Infection of the heart's inner lining (endocardium). Fever, fatigue, heart murmur, and signs of heart failure. Meningitis Rare complication of systemic spread. Severe headache, fever, neck stiffness, altered mental status.

61. Laboratory procedure for investigation Sample Collection : Collect samples from infected sites, such as wounds, respiratory secretions, or blood. Culture : Inoculate the samples onto appropriate culture media like blood agar or MacConkey agar. Pasteurella species are fastidious and may require specific growth conditions Identification : Use biochemical tests or commercial identification systems to confirm the presence of Pasteurella. Common tests include oxidase, catalase, and indole tests Gram Stain : Perform a Gram stain to observe the bacteria's morphology and Gram reaction.

62. Laboratory procedure for investigation Serotyping : Some Pasteurella species can be serotyped using specific antisera to identify variations. Molecular Techniques: Polymerase chain reaction (PCR) and DNA sequencing can be employed for accurate species identification.

63. Treatment Antibiotics : Antibiotics are the mainstay of treatment. Choice based on bacterial susceptibility testing. Commonly used antibiotics include Penicillin (e.g., amoxicillin-clavulanate),Cephalosporins (e.g., ceftriaxone),Fluoroquinolones (e.g., ciprofloxacin),Combination therapy considered for severe infections. Supportive Care: Manage symptoms such as fever and pain, Adequate hydration and nutrition. Surgical Intervention : Drain abscesses: Removal of pus to relieve pressure and aid healing. Debridement: Surgical removal of infected tissue to prevent spread. Especially important for deep tissue or systemic infections.

64. Treatment Antibiotic Prophylaxis Consider prophylactic antibiotics for high-risk animal bites or scratches. Especially important if the wound is deep, contaminated, or involving a joint. Tetanus Vaccination Ensure up-to-date tetanus vaccination, especially for deep or puncture wounds. Tetanus booster recommended every 10 years. Prompt Medical Attention Seek medical care promptly after an animal-related injury. Early treatment can prevent infection and complications.

65. Treatment Animal Contact Awareness Educate individuals about the risks of animal bites and scratches. Encourage caution when interacting with animals, especially unfamiliar ones. Proper Animal Handling Teach safe methods for handling pets and animals. Avoid provoking animals that might lead to aggressive behavior. Wound Care Thoroughly clean and disinfect animal-related wounds immediately. Wash wounds with soap and water to remove bacteria.

66. GENUS NEISSERIA

67. History The genus  Neisseria  is named after the German bacteriologist  Albert Neisser, who in 1879 discovered its first example,  Neisseria gonorrhoeae , the pathogen which causes the human disease gonorrhea. Neisser also co-discovered the pathogen that causes leprosy,  Mycobacterium leprae . These discoveries were made possible by the development of new staining techniques which he helped to develop.

68. Classification Kingdom- monera Phylum- protobacteria Class- betaproteobacteria Order- neisseriales Family- Neissriaceae Genus- Neisseria Species- species of clinical significance; gonorrhoea , meningitidis

69. Morphology Are gram negative Diplococci- occurs as two joined cells Non- motaile : lack flagella Do not produce spores Have capsule ( N. meningitidis ) N. gonorrhoea lack capsule

70. Cultural characteristics: N. gonorrhoea N. gonorrhoeae is a fastidious coccus It requires complex media for growth: These cannot grow on ordinary media They are aerobes but can also grow anaerobically. They grow optimally at a temperature range of 35–36°C. They fail to grow at temperature less than 25°C or greater than 37°C. The growth of bacteria is enhanced by incubation in humid atmosphere supplemented with 5–10% CO2 concentration

71. Cultural morphology: on Blood agar N. gonorrhoeae produces convex small colonies These colonies are translucent with entire edges and finely granular surface.

72. Selective media Thayer Martin medium : its chocolate agar medium containing antibiotics, such as colistin, nystatin, and vancomycin Modified New York City medium: its a translucent medium containing vancomycin, colistin, trimethoprim, and either nystatin or amphotericin B These selective media are used for isolation of gonococci from the clinical specimens containing mixed microbial flora. On these media, N. gonorrhoeae produces small, translucent, and convex colonies, which are soft and easily friable

73. Transport media Stuart’s transport medium is used for the collection and transport of clinical specimens to the laboratory for isolation and demonstration of N. gonorrhoeae

74. Biochemical characteristics of Gonococci Gonococci ferment glucose with the production of acid but no gas. They do not ferment maltose, lactose, sucrose, or fructose. This is an important feature to differentiate N. gonorrhoeae from N. meningitidis. N. gonorrhoeae utilizes glucose only, whereas N. meningitidis utilizes both glucose and maltose. They do not reduce nitrates, They do not produce hydrogen sulfide (H2S) . Oxidase positive Catalase positive .

75. Morphology of N.meningitidis Are Gram-negative They are spherical, or oval cocci arranged in pairs with the adjacent sides flattened. They measure 0.6–0.8 um in diameter. Freshly isolated bacteria are usually capsulated (have a capsule). They are non-motile (lack flagella) Non-sporing (do not produce spores)

76. Biochemical characteristics of N.meningitidis Oxidase positive Catalase positive These two tests are important biochemical markers for preliminary identification of this organism. N. meningitidis ferments glucose and maltose with acid but no gas. It does not ferment sucrose or lactose. It does not produce hydrogen sulphide Does not reduce nitrate to nitrite.

77. Cultural characteristics of N.meningitidis meningococci are strict aerobes (they grow and survive only in the presence of oxygen) They grow optimally at a temperature between 36°C and 39°C . optimum pH of 7.4–7.6. Their growth is enhanced by incubation in a moist atmosphere in the presence of 5% CO2 concentration . Meningococci are fastidious bacteria with complex nutritional requirements.

78. Blood agar N. meningitidis produces small, round (1–2 mm in diameter), convex, gray, and translucent nonpigmented colonies with entire edges after 24 hours of incubation. It does not produce any hemolysis on blood agar . Strains of meningococci with large polysaccharide capsule appear as mucoid colonies. Meningococci produce large colonies on chocolate agar.

79. Selective media Thayer Martin medium with antibiotics (vancomycin, colistin, nystatin, and trimethoprim) New York City medium are the selective media commonly used for the isolation of the bacteria from clinical specimens containing mixed bacterial flora. N. meningitidis should appear as  large, round, smooth, convex, colorless-to-grey, opaque colonies  on the Thayer Martin medium with no discoloration of the medium.

80. Pathogenesis: N. gonorrhoea Virulence factors Capsule - Prevents phagocytosis Pili- Mediate attachment of gonococci to nonciliated epithelial cell; prevent ingestion and killing of gonococci by neutrophils Por proteins- Confer resistance to serum killing of gonococci by preventing fusion of phagolysome in neutrophils Opa proteins- Mediate bacterial adherence to each other, and to the eukaryotic cells

81. Virulence factors ( continued…) Rmp proteins- Produce antibodies that block serum bactericidal activity against gonococci Lipo-oligosaccharide (LOS)- Possesses endotoxic activity of the bacteria IgA protease- Destroys IgA immunoglobulin Beta-lactamase- Degrades beta-lactam rings in the penicillin Plasmids- Plasmid-borne virulence determinants are associated with antimicrobial resistance

82. Clinical diseases Gonorrhea Gonorrhea is a sexually transmitted disease. It is primarily a genital infection restricted to the urethra in men and cervix in women. The incubation period varies from 2 to 8 days.

83. Gonorrhea in men Asymptomatic acute infection is seen in approximately 95% of all infected men. Urethritis is the major clinical manifestation, with burning urination (micturition) and serous urethral discharge as the initial manifestation Subsequently, the discharge becomes more profuse, purulent(containing pus), and even blood-tinged. Acute epididymitis, prostatitis, and peri-urethral abscess are rare, but are noted gonococcal complications in men.

84. Gonorrhea in women In women, endocervix is the primary site (80–90%) of infection because gonococci invade only the endocervical columnar epithelial cells. The infection is mostly asymptomatic in women. Symptoms The presence of vaginal discharge, Dysuria (Pain or burning sensation while passing urine) Dyspareunia(painful sexual intercourse) mild lower abdominal pain In 10–20% of infected women, the primary infection may spread

85. Disseminated gonococcal infections(DGI) (DGI) occurs because of hematogenous dissemination of gonococci from the primary site of infection. Arthritis-dermatitis syndrome is the classic presentation of DGI. Joint or tendon pain is most common in the early stage of infection. Migratory polyarthrititis , especially of the knees, elbows, and more distal joints, and also tenosynovitis are the common symptoms. Skin lesions include maculopapular to pustular lesions often with a hemorrhagic component. Septic arthritis, especially of the knee, is the next stage of DGI. NOTE: The DGI is mostly seen in untreated asymptomatic women and in persons with complement deficiency.

86. Ophthalmia neonatorum It’s a non-sexually transmitted infection caused by N. gonorrhoeae . This is a condition of bilateral conjunctivitis of a neonate born by vaginal delivery to an infected mother. However, transmission to the newborn can also occur in utero or in the postpartum period. The common symptoms are pain in the eyes, redness, and purulent discharge . Blindness is a complication of this condition.

87. Pathogenesis: N.meningitidis Virulence factors Capsule- Prevents phagocytosis LOS endotoxin- Causes damage of the blood vessels associated with meningococcal infections IgA protease- Destroys IgA immunoglobulin, thereby helps gonococci to attach to the epithelial cells of the upper respiratory tract Lipo-oligosaccharides- Stimulates release of TNF-a, which results in host cell damage

88. Meningitis N. meningitidis colonizes the human nasopharynx, and under specific conditions, invades the blood stream and then reaches the brain, causing meningitis. Meningococcal meningitis caused by N. meningitidis is most common in children and young adults. It is a febrile illness of short duration characterized by: Headache and stiff neck. Lethargy or drowsiness is frequent. Confusion, agitated delirium, and stupor are rarer. Mental obtundation: its mild to moderate alertness reduction (altered level of consciousness) with decreased interest in the environment and slower than normal reactivity to stimulation. Stupor(state of near unconsciousness) and coma due to increased intracranial pressure are some of the noted complications at the end stage of the disease.

89. Meningococcemia  it’s a blood infection caused by the bacterium Neisseria meningitidis , also called meningococcus The condition presents as: an acute fever with petechial rash. Small petechial rashes (these pinpoint red dots on the skin are caused by broken capillaries) are continuously found on the trunk and lower extremities; subsequently the rashes may coalesce to form large hemorrhagic lesions.

90. Meningococcemia Non-suppurative arthritis, usually of the knee joint, is seen in approximately 10% of the patients with meningococcal disease. This condition is observed within the first 48 hours of treatment and is believed to be immunologically mediated. Recurrent meningococcal meningitis is another condition which is associated with hereditary deficiency of various components of complement system. Other conditions include meningococcal pneumonia (which probably results from the aspiration of the organisms), septic arthritis, purulent pericarditis, and endophthalmitis

91. Laboratory diagnosis of N. gonorrhoeae Specimen: urethral discharge in males cervical discharge in females are the specimens of choice. High vaginal swab in females

92. Specimen processing Culture and isolation culture confirms the diagnosis of gonorrhea. Genital, rectal, and pharyngeal specimens are inoculated on a nonselective medium (e.g., blood agar or chocolate agar) and on a selective medium (e.g., Modified Thayer Martin medium). The colonies of gonococci on chocolate agar are small, round, translucent, and convex with finely granular surface. On Thayer Martin medium, the colonies show similar morphology as that on chocolate agar.

93. Microscopy Gram stain of urethral exudates: The presence of four or more polymorphonuclear (PMN) leukocytes per oil-immersion field in Gram-stained urethral exudate smear is diagnostic of urethritis:

94. Detection of gonococcal antigen The gonococcal antigens can be detected by both direct fluorescent antibody (DFA) test and direct enzyme-immunoassays (EIA) in urethral discharge and endocervical discharge as well as in other clinical specimens. The DFA using fluorescein-conjugated monoclonal antibodies is a rapid and useful method for demonstration of gonococcal antigens in clinical specimens. The EIA using polyclonal antigonococcal antibodies are also used for the detection of gonococcal antigens in clinical specimens

95. Serodiagnosis The serological tests are done to detect gonococcal antigens or specific anti-gonococcal antibodies in the serum for diagnosis of gonorrhea. ELISA and RIA ( radioimmunoassays ) using whole cell lysates, pilus proteins, and LPS antigens of the gonococci demonstrate antibodies in the serum. NOTE: These serological tests are not recommended for routine use. These are used only in specific situations, such as chronic gonorrhea, gonococcal arthritis, etc

96. Treatment and control CDC recommends a single dose of 500 mg of intramuscular ceftriaxone . Alternative regimens are available when ceftriaxone cannot be used to treat urogenital or rectal gonorrhea. Although medication will stop the infection, it will not repair any permanent damage done by the disease. 

97. Diagnosis of N.meningitidis infection Specimen Cerebrospinal fluid and blood are the specimens of choice for demonstration of meningococci in the early stage of meningitis. Nasopharyngeal swabs are useful to detect carriers. NB: The CSF is collected by lumbar puncture and blood by venipuncture in strict aseptic conditions. CSF is never refrigerated as Haemophilus influenzae, another agent of meningitis, may die at the cold temperature.

98. Microscopy Gram staining Microscopy Gram staining of the CSF is a very useful method for detection of meningococci. Meningococci are seen as Gram-negative diplococci present mainly inside the leukocytes and some may even be present extracellularly. These cocci can be demonstrated in the CSF in approximately 50% of the patients with meningococcal meningitis. In fulminant meningococcemia, Gram staining of the peripheral blood buffy coat may reveal Gram-negative diplococci.

99. Culture and Isolation N. meningitidis can be isolated from the CSF, blood, and other clinical specimens by culture confirms the diagnosis of meningococcal infection. The CSF is inoculated immediately on a nonselective medium, such as blood agar or chocolate agar, and incubated at 35–36°C under 5% CO2 for 18–24 hours. The colonies of meningococci are small, round, translucent, and convex with a smooth glistening surface. Blood is inoculated immediately into blood culture bottles containing either glucose broth or sodium taurocholate broth and incubated at 35–36°C. Subcultures are made on blood agar or chocolate agar from these broths and are re-incubated overnight at 35–36°C in the presence of 5% CO2 . The cultures should be incubated for 4–7 days with daily subculture. Blood culture is often positive during early stage of meningitis and in meningococcemia.

100. Antigen detection Detection of soluble polysaccharide antigen in the CSF is a useful method for diagnosis of meningococcal meningitis. Counter-current immunoelectrophoresis, latex agglutination test, and bacterial coagglutination test using specific antibodies are the rapid tests frequently used to detect the soluble antigen in the CSF. Antigen detection is useful when bacteria are scanty in the CSF. However, antigen detection is not useful in the meningitis caused by Group B meningococci because N. meningitidi s serogroup B is relatively non-immunogenic and does not react with specific antibodies

101. Serological tests Serodiagnosis Indirect hemagglutination test and ELISA are useful for the demonstration of antibodies against specific polysaccharide antigen in the serum. Serodiagnosis is useful in the cases of chronic meningococcal infection where cultures have proved negative for meningococci

102. Treatment of meningococcal infection Antimicrobial chemoprophylaxis of close contacts is the key factor for preventing secondary cases of sporadic meningococcal disease. Sulfonamides, rifampin, minocycline, ciprofloxacin, and ceftriaxone are the drugs frequently used to eradicate meningococci from the nasopharynx. However, ciprofloxacin is not recommended for children, because it has been found to cause cartilage damage in immature experimental animals.

103. Prevention Immunoprophylaxis by vaccination is very much useful for prevention of meningococcal disease. You can prevent meningitis from spreading by washing your hands vigorously, especially after you use the bathroom, change a diaper, spend time in a crowded place, and cough or blow your nose

104. THANK YOU .