Enterobacter Aerogenes Essay
There are lots of different known microorganisms in the biosphere of the earth which can help or harm all living things. These microorganisms can be in a group of bacteria, fungi, some are archaea or protists. Likewise, they are called microorganisms because they can be seen using a microscope only. They are grouped and subdivided for distinctions of each different species. And, one of these microorganisms, in the group of bacteria, is the “Enterobacteriaceae family which has a subpopulation of beta-lactamase–producing organisms” (Fraser et al. , 2006).
These species are the most frequent bacterial isolates recovered from clinical specimens. In the article by Chief Doctor Susan Fraser of Infectious Diseases Service, with Arnett and Sinave, said that the “[p]atients most susceptible to acquiring Enterobacter infections are those who stay in the hospital […] for prolonged periods” (Fraser et al. , 2006). It was also stated that the demonstration by the national surveillance program about Enterobacter species has been a significant source of morbidity and mortality in the hospitalized patients in the United States (Fraser et al. 2006).
Also, it was reported that “Enterobacter species were the second most common gram-negative organism behind Pseudomonas aeruginosa” (Fraser et al. , 2006). In addition, from the article ‘Extended-Spectrum Beta-lactamase (ESBL) producing Enterobacter aerogenes phenotypically misidentified as Klebsiella pneumoniae or K terrigena’ reported that the “isolates from clinical E aerogenes is hard to identify and may result as Klebsiella because of delayed positivism for ornithine decarboxylase and motility” (Claeys et al. 4(1):49). It showed that the findings’ regarding E aerogenes is not easy to identify from other microorganisms. On the contrary, the correct identification is possible thru the presence of an ‘inducible beta-lactamase’ (Fraser et al. , 2006).
So, the possibility to cure the disease is still guaranteed and base from the laboratory tests made by doctors, “carbapenems have the best activity against E aerogenes [and] others are fourth-generation cephalosporins, aminoglycosides, fluoroquinolones, and TMP-SMZ” (Fraser et al. 2006). Description of Enterobacter aerogenes, its morphology or structure and etc. From the observation of Fraser and her colleagues, they have said that “Enterobacter species contain a subpopulation of organisms that produce a beta lactamase at low-levels” (Fraser et al. , 2006l). They further explained that “[o]nce exposed to broad-spectrum cephalosporins [then] the subpopulation of beta [-lactamase]–producing organisms predominates” (Fraser et al. , 2006).
In other words, at the time of diagnosis that an infection appears sensitive to cephalosporins, it is possible to quickly develop into a resistant infection during therapy. They also remarked that “[…] Enterobacter aerogenes are important nosocomial pathogens responsible for various infection, lower respiratory tract infections, skin and soft tissue infections, urinary tract infections (UTIs), endocarditis, [intra]-abdominal infections, septic arthritis, osteomyelitis and ophthalmic infections” (Fraser et al. , 2006). However, individuals that have no sickness are not easily infected by E aerogenes.
An opportunistic bacterium as named by doctors because it is said to have an endotoxin which is known to play a major role in the pathophysiology of sepsis and its complications and that Enterobacter aerogenes has been the most frequent carrier of ESBL (Fraser et al. , 2006). The colonies of Enterobacteriaceae family appeared large, dull-gray and dry or mucoid on sheep blood agar. The Enterobacteriaceae family including E aerogenes, “is composed of Klebsiella, Escherichia, Citrobacter, Serratia, Salmonella, Shigella species, and many others” (Fraser et al. 2006). As well as, “these bacteria have an outer membrane that contain lipopolysaccharides from which lipid-A plays a major role in sepsis” (Fraser et al. , 2006). To further discuss, Lipid-A or endotoxin is the major stimulus for the release of cytokines which are the mediators of systemic inflammation and its complications. Moreover, “Enterobacter species are motile, usually ornithine decarboxylase-positive, and urease-negative” (Fraser et al. , 2006). How does E aerogenes can be collected and transported?
Enterobacter species are often recovered from wounds, urine, blood and spinal fluid of hospitalized patients (. eMedicine). “Enterobacter species infections include hospitalization of greater than 2 weeks, invasive procedures in the past 72 hours, treatment with antibiotics in the past 30 days, and the presence of a central venous catheter [are the risk factors involved]” (Fraser et al. , 2006). Also, for someone infected with ‘nosocomial multidrug-resistant strains’ species includes the recent use of ‘broad-spectrum cephalosporins or aminoglycosides’ and ICU care (Fraser et al. 2006). Furthermore, patients most susceptible to acquiring Enterobacter infections are those who stay in the hospital for prolonged periods.
“Other major risk factors include the prior use of antimicrobial agents, ulcers of the upper gastrointestinal tract, use of foreign devices such as intravenous catheters and serious underlying conditions such as burns, mechanical ventilation and immunosuppressant” (Fraser et al. , 2006). The source of infection, base on Fraser et al. they said that it “may be endogenous via colonization of the skin, gastrointestinal tract, or urinary tract or exogenous resulting from the ubiquitous nature of these bacteria. ” Besides, multiple reports have incriminated the hands of personnel, endoscopes, blood products and stethoscopes as sources of infection. What are the signs/symptoms of an infection/disease caused by this organism? Enterobacter causes considerable suffering among many patients; with chronic diseases individuals are the most prone to be infected by this pathogen.
Furthermore, the signs or symptoms are considerably hard to identify but along with signs of infection (leukocytic infiltration), histology should reveal the presence of bacterial rods However, the causes by which these pathogens inflict are recognizable. Such as: (1. ) having a ventilator-associated pneumonia, (2. ) Enterobacter is a major pathogen in early post–lung transplant pneumonia wherein the bacteria came from the donor. As remarked, “symptoms of Enterobacter pneumonia are not specific to these bacteria and fever, cough, production of purulent sputum, tachypnea and tachycardia are usually present” (Fraser et al. 2006).
What biochemical or other tests would be used to identify this organism and the results? In the journal article by Ghisalberti, Mahamoud, Chevalier, Baitiche, Martino, Pages and Barbe; regarding the test made for the resistance of E aerogenes to drugs, it is reported that “Efflux mechanisms protect bacterial cells by pumping out toxic compounds and actively contribute to bacterial multidrug resistance and the agents inhibiting efflux pumps are for the control of multidrug-resistant bacterial infections” (Ghisalberti et al. 27(6):565-9).
They stated the “effects of new chloroquinoline derivatives that render resistant Enterobacter aerogenes isolates noticeably more susceptible to structurally unrelated antibiotics” (Ghisalberti et al. , 27(6):565-9). In addition, “some of the molecules tested in this work are able to inhibit the main efflux pump involved in E. aerogenes antibiotic resistance” (Ghisalberti et al. , 27(6):565-9).
On the other hand, regarding the written article by Chevalier, Pages and Mallea; ‘in vivo modification of porin activity conferring antibiotic resistance to Enterobacter aerogenes’, they stated that one isolate exhibited a strong modification of the porin antigenic pattern, and with an immunological probe directed against an epitope located inside the pore lumen (Chevalier et al. , p. 248-51). They said that “strong decrease of cefepime uptake was evidenced for this isolate” (Chevalier et al. p. 248-51).
It was observed as likely in porin-deficient strains: “these resulted on a serious alteration of the channel properties which may support cephalosporin resistance“(Chevalier et al. , p. 248-51). Which antibiotic(s) would be effective in the treatment of the infection/disease caused by this organism? “Patients infected with Enterobacter pathogens are advised by physicians to avoid certain antibiotics” (Fraser et al. 2006), especially the third generation cephalosporins, because they said, “resistant mutants can quickly appear” and “the crucial first step is appropriate identification of the bacteria” (Fraser et al. , 2006). “Imipenem and cefepime have a […] stable beta-lactam ring against the lactamase produced by resistant strains of Enterobacter” (Fraser et al. , 2006).
Base from Fraser et al. , “[t]he antimicrobials most indicated in Enterobacter infections are carbapenems, fourth-generation cephalosporins, aminoglycosides, fluoroquinolones, and TMP-SMZ. “Carbapenems have the best activity against E cloacae, E aerogenes, and others. ” It was noted that bacterial resistance to antibiotics continues to be a significant threat and many strains of Enterobacter species are already resistant to many antibiotics. Likewise, the presence of inducible resistance genes on plasmids in other members of the Enterobacteriaceae family is concerning for the possibility of transfer of genes between bacteria, resulting in the development of further resistance in E. species.
Isolation and barrier protection should be implemented for the prevention of an outbreak, for instance, when Enterobacter infections occur. In addition, isolation precautions should also be implemented when a multidrug-resistant organism is isolated. Also, hand washing or use of alcohol or other disinfecting hand gels by health care workers between contacts with patients prevents transmission of these and other nosocomial bacteria (Fraser et al. , 2006).
“Failure to select appropriate antibiotics for treatment is a significant problem with potential legal implications” (Fraser et al. 2006). When someone is infected by these species, consultation with an infectious diseases specialist can be of tremendous help in determining appropriate antibiotic treatment. However, good antibiotic prescription, good monitoring of bacterial resistance and good infection-control practices are among the most important measures that should be in place in each hospital. Also, everyone who cares for the prevention can assist in reducing the rates of nosocomial infections.
University/College: University of California
Type of paper: Thesis/Dissertation Chapter
Date: 18 February 2017
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