*5.3.2. Structure and pathogenesis*

Pseudomonas aeruginosa is a gram-negative, rod shaped, asporogenous and monoflagellated, noncapsular bacterium but many strains have a mucoid slime layer. Pseudomonas has an incredible nutritional versatility. Pseudomonas can catabolize a wide range of organic molecule including organic compounds such as benzoate. This, then make Pseudomonas a very ubiquitous microorganism and Pseudomonas is the most abundant organism on earth [43] (**Figure 3**).

Pseudomonas is widely distributed in nature and is commonly present in moist environment of hospitals. It is pathogenic only when introduce into areas devoid of normal defense such as disruption of mucous membrane and skin, usage of intravenous or urinary catheters and neutropenia due to cancer or in cancer therapy. Its pathogenic activity depends on its antigenic structure, enzymes and toxins [44]. Among the enzymes Catalase, Pyocyanin, Proteases, elastase, haemolysin, Phospholipase C, exoenzyme S and T and endotoxin and endotoxin A play role in disease process and as well as immunosuppression. Pseudomonas can infect almost any organ or external site. Pseudomonas in invasive and toxigenic. It attached to and colonized the mucous membrane of skin. Pseudomonas can invade locally to produce systemic disease and septicemia. Pseudomonal UTs are usually hospital acquired and are associated with catheterization, instrumentation and surgery. These infections can involve the urinary tract through an ascending infection or through bacteriuria spread. These UTIs may be a source of bacteraemia or septicemia [45].

#### *5.3.3. Laboratory diagnosis*

enzymes such urease and proteases, toxins such as Haemolysin Hpm A and iron nutrient

**Figure 2.** Gram stain picture and morphology of Proteus. Adapted from CCBC faculty web. BIOL 230 Lab Manual: gram stain of Proteus mirabilis and Proteus vulgaris bacteria (SEM) | Macro & Micro: Up Close and Personal | Pinterest |

The infection with Proteus can be diagnosed by taking a urine sample for microscopy and culture which is sufficient in most of the cases except in few cases where advanced diagnostic tools are used. If the urine is alkaline, it is suggestive of infection with Proteus sp. The diagnosis of Proteus is made on swarming motility on media, unable to metabolized lactose and has a distinct fishy door. Ultrasound or CT scan to identify renal stone (Struvite stone) or to visualized kidneys or surrounding structures. It will allow to exclude other possible

Pseudomonas is a gram-negative bacteria belonging to the family Pseudomonadaceae and containing 191 validly described species [37]. Because of their widespread occurrence in water and plant seeds, the pseudomonas was observed in early history of microbiology. Pseudomonas is flagellated, motile, aerobic organism with Catalase and oxidase-positive. Pseudomonas may be the most common nuclear or of ice crystals in clouds, thereby being of utmost importance to the formation of snow and rain around the world [38]. All species of Pseudomonas are strict aerobes, and a significant number of organisms can produce exopolysaccharides associated with biofilm formation [39]. Pseudomonas is an opportunistic human pathogen that is especially adept at forming surface associated biofilms. Pseudomonas causes catheter associated urinary tract infection(CAUTIs) through biofilm formation on the surface of indwelling catheters, and biofilm mediated infection including ventilator associated pneumonia, infections related to mechanical

heart valves, stents, grafts, sutures, and contract lens associated corneal infection [40].

problems, mimicking symptoms of urinary tract infection [35, 36].

Microbiology, Bacteria shapes and Fungi. https://www.pinterest.com › pin.

28 Microbiology of Urinary Tract Infections - Microbial Agents and Predisposing Factors

acquisition proteins.

*5.2.3. Laboratory diagnosis*

**5.3. Pseudomonas in CAUTI**

*5.3.1. Introduction*

Identification of bacterium with microscopy is simple method of identification of pseudomonas. Culture and antibiotic sensitivity pattern can be done in most laboratory media commonly on blood agar or eosin-methylthionine blue agar. Pseudomonas has inability to ferment lactose and has a positive oxidase reaction. Fluorescence under UV light is helpful in

**Figure 3.** Gram stain picture and morphology of Pseudomonas aeroginosa. Adapted from Science News. A new antibiotic uses sneaky tactics to kill drug-resistant Pseudomonas aeruginosa illustration and Pseudomonas Aeruginosa Stock Photos & Pseudomonas Aeruginosa Stock Images—Alams. https://www.alamy.com › stock-photo.

early identification of colonies. Fluorescence is also used to suggest the presence of pseudomonas in wounds [46].

the surface of Klebsiella. They can be as long as 10 μm and between 1 and 11 nm in diameter. Among the two types of pili—type 1 (fim) pili and type 3 (mrk) pili, type 1 aids virulence by their ability to adhere with mucosal surfaces and type 3 pili strongly associated with biofilm production [50]. Both fim and mrk pili are considered part of the core genome [51]. It is thought that both types of pili play a role in colonization of urinary catheters, leading to CAUTI [52]. In addition to fim and mrk pili, a number of additional usher-type pili have been identified in Klebsiella with an average of ~8 pili clusters per strain. Based on varying gene frequencies, some of these appear to be part of the accessory genome. Immediately after catheterization Klebsiella starts biofilm production on the inner as well as outer surface of the catheter and on urothelium. Biofilm augments migration of Klebsiella into urethra and urinary bladder. Biofilm formation on the catheter surface by *Klebsiella pneumoniae* causes severe problem. Type 1 and type 3 fimbriae expressed by *K. pneumoniae* enhance biofilm formation on urinary catheters in a catheterized bladder model that mirrors the physicochemical conditions present in catheterized patients. These two fimbrial types does not is expressed when cells are grown planktonically. Interestingly, during biofilm formation on catheters, both fimbrial types are expressed, suggesting that they are both important in promoting biofilm formation on catheters [53]. The biofilm life cycle illustrated in three steps: initial attachment events with inert surfaces type 1 and type 3 fimbriae encoded by the mrk ABCDF gene cluster within *K. pneumoniae* promotes biofilm formation [54, 55]. Detachment events by clumps of Klebsiella or by a 'swarming' phenomenon within the interior of bacterial clusters, resulting in so-called 'seeding dispersal'.

Microbiology of Catheter Associated Urinary Tract Infection

http://dx.doi.org/10.5772/intechopen.80080

31

Modifiable risk factor are prolonged catheterization, lack of adherence to aseptic catheter care, insertion of the indwelling urethral catheter in a location other than an operating room, presence of a urethral stent, feecal incontinence. Non-modifiable risk factor—renal disease (i.e., serum creatinine >2 mg/dL), diabetes mellitus, older age (i.e., age > 50 years old), female sex, malnutrition and severe underlying illness [53]. For infection several virulence factors such as surface factors (fimbriae, adhesins, and P and type 1 pili) and extracellular factors toxins, siderophores, enzymes, and polysaccharide coatings are necessary for initial adhesion with colonization of host mucosal surfaces for tissue invasion overcoming the host defense

Diagnosis of klebsiella infection is by isolation and laboratory identification of bacterium from urine or biofilm. Laboratory diagnosis can be done by culture of specimen—urine or catheter biofilm in blood agar, MacConkey's agar. Specific ELISA, latex agglutination tests, PCR and other immunological-based detection methods are sophisticated alternatives for diagnosis of klebsiella. Determination of a gene on capsule of Klebsiella is rapid and simple method for the

Enterobacter species, particularly Enterobacter cloacae and *Enterobacter aerogenes*, are important nosocomial pathogens responsible for about 1.9–9% CAUTI, rarely causes bacteremia [57, 58]. *Enterobacter cloacae* exhibited the highest biofilm production (87.5%) among isolated pathogens [53].

determination of the K types of most *K. pneumoniae* clinical isolates [56].

mechanisms, and causing chronic infections [55].

*5.4.3. Laboratory diagnosis*

**5.5. CAUTI with Enterobacter**

*5.5.1. Introduction*
