Case Study Pathogenic Bacteriology 2009 Case 10, 46 & 53 Borja, Rebecca Loi, William Mansourian, Mourad.

Case StudyPathogenic Bacteriology

2009Case 10, 46 & 53

Borja, RebeccaLoi, William

Mansourian, Mourad

Presented by:

William Loi

Case 10

Age & Sex: 48 years old; Male

Medical History: Long history of alcoholism

Alcoholic hepatitis Hallucinosis

Description(s): Admitted to the ICU

Hypotension and GI bleeding Treatment(s)

Intubated, IV fluids, RBC transfusion Remained intubated and ventilator dependent for several weeks

Fevers, and treated with wide-spectrum antibiotics Specimen(s)

By tracheal aspirate – Staphylococcus aureus Given further antibiotic therapy

Gram staining result(s) from trachea Polymorphonuclear leukocytes (PMNs) Gram-negative rod

Case 10 Summary

Figure 1

Key Information Pointing to Diagnosis

Description(s): Chest radiograph result(s)

Infiltrate and changes consistent with multiple small abscesses Specimen(s)

Obtain the sample by tracheal aspirate Sheep blood agar (Fig. 2A) MacConkey agar plate (Fig. 2B) Disk susceptibility plate (Fig. 3)

Key Information to Diagnosis – Cont'd

Fig. 2A Sheep blood agar

Mucoid, smooth colonies

Fig. 2B MacConkey agar

Colorless, shinny, non-lactose fermenter

Figure 3 Disk susceptibility plate

Green pigment produced on the surface

Susceptible Resistant

Key Information to Diagnosis – Cont’d

Isolated by eosin-methylthionine blue agar Fruity odor Pigment production – blue-green color (pyocyanin) Able to grow at 42°C Catalase: Positive Oxidase: Positive Lipase: Positve

TSI: K/K, No gas, No H2S

H and O Antigens

Other Key Diagnosis to Diagnose – Cont'd

Agent of infection Pseudomonas aeruginosa.

Classification: Family: Pseudomonadaceae Genus: Pseudomonas Species: aeruginosa

Common cause of nosocomial infections Pneumonia Urinary tract infections Surgical wounds Sepsis

Immunocompromised individual Patients with Cystic Fibrosis (CF) Cancer Burn wounds Bone marrow transplantation

Multidrug-resistant P. aeruginosa was discovered in 1979 in Robert Fass in vitro studies

Disease(s) caused by the bacteria

This organism produces exotoxin A that is similar to diphteria toxin produced by Corynebacterium diphtheriae

Top: P. aeruginosa Exotoxin A Bottom: C. diphtheriae toxin (DT)

3 functional domains: Activity (ADP-R) Translocation (T) Receptor (R/B)

Both inhibit ADP-Ribosylate Elongation Factor 2

Functional domains are organized in reverse order

P. aeruginosa Exotoxin A

(Deng & Barbieri, Annu. Rev. Microbiol., 2008)

Typical Protein SynthesisHost receptor

Nascent protein

mRNA

ADP-ribosylate EF-2

Endoplasmic Reticulum

Golgi Apparatus

Exotoxin A

A Toxin

Nascent protein

Host receptorExotoxin A

Golgi Apparatus

Endoplasmic Reticulum

mRNA

ADP-ribosylate EF-2

Patients with CF are highly susceptible to P. aeruginosa infections Abnormal secretion of viscous mucus in the lungs Decreased airway fluid, resulting in reduced ciliary clearance of aspirated

microbes It leads to colonization of the organism P. aeruginosa resists to host immune responses – embedded in biofilms in the

lungs of CF patients Thus, plays a critical role in preventing effective opsonization and

phagocytosis of P. aeruginosa cells.

Other mechanism in successful pathogenesis (i) Elastolytic and (ii) non-elastolytic proteases P. aeruginosa disseminates in to the body with the use of elastolytic proteases. Elastin, which can be found in lung tissue and blood vessels, is broken down

by this protease. The breakdown of this compound causes an inflammatory reaction that aids in

the dissemination of the organism. Inactivate complement, cleave IgG & IgA antibodies, inactivate interferon

(INF), tumor necrosis factor (TNF) and some other cytokines

Pathogenesis of the disease

This organism was isolated after the patient received a prolonged course of broad-spectrum antibiotics.

This therapy predispose the patient to infection with this organism Hospitalization

The patient is highly susceptible to infections with this organism. Background

Alcoholic Alcoholic hepatitis

P. aeruginosa frequently cause hospital-acquired infections, particularly in immuno-compromised or critically ill patients

This organism able to survive in the presence of antimicrobial agents Broad range of antibiotic treatment Treatment to the primary staphylococcal infection allowed the

organism to undergo outer membrane changes resulting in resistance to a wide range of antibiotics.

Pathogenesis of the disease

Neutropenic patients are at increased risk for bacteremia with this organism

Steps could be taken to minimize the risk Treatment with one active beta-lactam antibiotic or combination of

aminoglycoside and β-lactam agent to achieve synergistic effects Increase awareness in managing equipments

Careful cleaning and monitoring of respirators, catheters, and other instruments

Administer effective antibiotic to the patients

Pathogenesis of the disease

Patients infected with mucoid P. aeruginosa had poorer survival than patients who had non-mucoid phenotype

Acquisition of mucoid P. aeruginosa was associated with an accelerated rate of decline in pulmonary function.

Immunocomprimised and CF patients are prone to P. aeruginosa infection

Frequently resistant to many commonly used antibiotics Common antibiotics:

Gentamicin Tobramycin, Colistin Fluoroquinolins

Triple antimicrobial therapy was suggested – ceftazidime, amikacin and sulbactam8

Prognosis, Treatment and Prevention of Infection of P. aeruginosa

Leung, C. H., et. al., 2008, Antimicrobial therapy and control of multidrug-resistant Pseudomonas aeruginosa bacteremia in a teaching hospital in Taiwan. Journal Microbiology, Immunology, and Infection, 41: 491-498 Purpose

Investigate the source of an outbreak of multi-drug resistant (MDR) P. aeruginosa Role of combination therapy

Methods Isolate MDR P. aeruginosa from MacKay Memorial Hospital, Taipei, Taiwan Perform antibiotic susceptibility tests Genetic analysis by pulsed-field gel electrophoresis from bacteremia patients

Results Combination of ceftazidime, amikacin and sulbactam showed significant results Found the major source of MDR P. aeruginosa and stringent infection control

Primary Research Article Contributing to the Understanding of the Disease caused by P. aeruginosa

Leung, C. H., et. al., 2008, Antimicrobial therapy and control of multidrug-resistant Pseudomonas aeruginosa bacteremia in a teaching hospital in Taiwan. Journal Microbiology, Immunology, and Infection, 41: 491-498 Results

Conclusion Triple antibiotics could be used as an alternative treatment for MDR P.

aeruginosa infection

Primary Research Article Contributing to the Understanding of the Disease caused by P. aeruginosa

Urinary tract infections, respiratory system infections, dermatitis, soft tissue infections, bacteremia, bone and joint infections, GI infections,

Typical symptoms: Fever, chills and production of purulent matter in infected wounds

Pathogen is Pseudomonas aeruginosa Antibiotic therapy: Gentamicin, tobramycin, colistin, and/or fluoroquinolins Prognosis:

Patients with CF infected by mucoid P. aeruginosa has poorer survival rate compared with non-mucoid P. aeruginosa

Prevention: Aseptic technique, and careful cleaning and monitoring of respirators, catheters,

and other instruments

Transmission: In health care units – disinfectants, respiratory equipment, food, sinks, taps,

toilets, showers and mops By visitors and patients to other facilities, patient to patient, direct contact of

contaminated reservoirs and by ingestion of contaminated foods and water

Threat is occurring in debilitated patients with diminished resistance resulting from other disease or therapy

Take Home Message

1. Chuang, H. L., et. al., 2009, Influence of Age on Susceptibility to Pseudomonas aeruginosa Exotoxin A-induced Hepatotoxicity in Long-Evans Rats. The Journal of Veterinary Medical Science, 71: 163-169.

2. Deng, Q., et. al., 2008, Molecular mechanisms of the cytotoxicity of ADP-ribosylating toxins. Annual Review of Microbiology, 62: 271-288.

3. Dunn, M., et. al., 1995, Ventilator-associated pneumonia caused by Pseudomonas infection. Clinics In Chest Medicine, 16: 95-109.

4. Döring, G., et. al., 2008, Vaccines and immunotherapy against Pseudomonas aeruginosa. Vaccine, 26: 1011-1024.

5. Forestier, C., et. al., 2008, Oral probiotic and prevention of Pseudomonas aeruginosa infections: a randomized, double-blind, placebo-controlled pilot study in intensive care unit patients. Critical Care, 12: R69.

6. Govan, J. R., et. al., 1996, Microbial pathogenesis in cystic fibrosis: mucoid Pseudomonas aeruginosa and Burkolderia cepacia. Microbiology and Molecular Biology Reviews, 60: 539-574.

7. Kwakman, P. H., et. al., 2008, Medical-grade honey kills antibiotic-resistant bacteria in vitro and eradicates skin colonization. Clinical Infectious Diseases, 46: 1677-1682.

8. Leung, C. H., et. al., 2008, Antimicrobial therapy and control of multidrug-resistant Pseudomonas aeruginosa bacteremia in a teaching hospital in Taiwan. Journal Microbiology, Immunology, and Infection, 41: 491-498.

9. Liang, H., et. al., 2009, Identification of a novel regulator of the quorum-sensing in Pseudomonas aeruginosa. FEMS Microbiology Letters, Published online March 2, 2009.

10. Moser, C., et. al., 2009, Novel experimental Pseudomonas aeruginosa lung infection model mimicking long-term host-pathogen interactions in cystic fibrosis. Acta Pathologica, Microbiologica, et Immunologica Scandinavica, 117: 95-107.

11. Mukhopadhyay, C., et. al., 2008, Ventilator-associated pneumonia with Col-S strans: a successful comeback of colistin! The Brazilian Journal of Infectious Diseases, 12: 444-446.

12. Sagel, S. D., et. al., 2009, Impact of Pseudomonas and Staphylococcus infection on inflammation and clinical status in young children with cystic fibrosis. The Journal of Pediatrics, 154: 183-188.

13. Wolf, P., et. al., 2009, Pseudomonas exotoxin A: from virulence factor to anti-cancer agent. International Journal of Medical Microbiology, 299: 161-176.

Reference