Colonization vs

Colonization

• The presence of in or on a with growth and multiplication but without tissue invasion or damage • Understanding this concept is essential in the planning and implantation of epidemiological studies in a healthcare infection prevention and control program Infection v. Colonization • Confusing colonization with infection can lead to spurious associations that may lead to expensive, ineffective, and time‐ consuming interventions Multi Drug‐Resistant Organisms Management in Long Term Care • Colonization may become infection when changes in the host Facilities Workshop occur

Louisiana Office of Public Health Healthcare‐Associated Program

Objectives Colonization: Definition

By the end of the presentation, attendees will be able to: • Colonization: presence of a on/in a host, with • Define colonization growth and multiplication of the organism, but without • Differentiate colonization from infections interaction between host and organism (no clinical expression, no immune response). • Apply appropriate laboratory test by common LTC infectious • agents Carrier: individual which is colonized + more • • Understand the necessity of communicating infectious status Subclinical or unapparent infection: presence of upon patient transfer microorganism and interaction between host and microorganism (sub clinical response, immune response). Often the term colonization is applied for relationship host‐ agent in which the immune response is difficult to elicit. • Contamination: Presence of a microorganism on a body surface or an inanimate object.

1 Colonization vs Infection

Spectrum: No Exposure ‐ Exposure ‐ Colonization ‐ Carrier Infection ‐ A carrier is an individual that harbors a specific microorganism Host + Infectious agent What is “Exposed” ? in the absence of discernible clinical disease and serve as a  No foothold: Exposed Means of : potential source of infection. A carrier may be an individual Foothold, no reaction Being in the same room as an who is: Colonization infectious tuberculous patient Carrier or with a person with HIV • colonized Foothold: epithelial attachment  Specific information: • infected and Multiplication: Infection Eating a meal or eating the contaminated food item?  • in before disease Direct cytotoxicity Exposure definition relies on  • convalescent from acute disease Toxins information that may not be all Tissue disruption known. The carrier status may be short or lengthy. Tissue injury Dissemination Think about carrier as •Source Asymptomatic  •Explanation for person who Symptomatic apparently is not infected

Flora at Colonization Sites Infection CONJUNCTIVA OROPHARYNX Staphylococci NASOPHARYNX Streptococcus viridans group Corynebacteria Staphylococci • The replication of organisms in host tissue which may cause Streptococcus pyogenes Haemophilus disease Streptococci Moraxella catarrhalis Staphylococci SKIN • Infection: defines the entrance and development of an Neisseria spp Moraxella catarrhalis Staphylococci infectious agent in a human or animal body, whether or not it Neisseria spp Haemophilus spp develops into a disease Corynebacteria Corynebacterium spp Propionibacteria • Caused by an infectious agent: all micro‐ or macro‐organisms Haemophilus spp UPPER INTESTINE Streptococci Candida capable of producing an infection or an infectious disease Anaerobes: Bacteroides Malassezia furfur Candida albicans Lactobacillus spp • Infectious disease: an illness caused by a specific infectious Candida spp agent or its toxic product that results from transmission of GENITOURINARY TRACT that agent or its product from an infected person, animal, or Staphylococci, Streptococci LOWER INTESTINE reservoir to a susceptible host Enterococci Aerobic G- bacilli: E.coli, Klebs Lactobacillus spp, Corynebacterium Enterobacter, Proteus, Serratia Neisseria spp, Anaerobes Providencia, Bacteroides, Anaerobic Candida albicans Enterococci, Streptococci, Candida

2 Colonization vs Infection

Skin Hand Flora RESIDENT FLORA Colonization Protects the Host • Survives on the skin more than 24 hours Normal flora protects against infectious originating at mucous membranes. • Not easily removed, hours of scrubbing There are several mechanisms for protection: • Complete stelirization ‐ Non specific stimulation of immune responsiveness impossible TRANSIENT FLORA ‐ Specific cross reactive immunization • Low virulence • Survive on skin less than 24 hours ‐ Competitive bacterial interference • Staphylococci, diphteroides,• Easily removed with soap and water • mostly Gram + , • Acquired during contacts with • very few Gram ‐ contaminated areas mouth, nose, perineal area, genitals, anal area, Germ free animals reared in good health succumb rapidly from catheter, bedpan, urinal, patient care overwhelming infection when transferred with normal healthy casual contact animals • May have high virulence Number of bacteria to colonize gut • Enterobacteria, Gram ‐ bacilli,  Normal animal, 10,000,000 Pseudomonas...  Germ free animal, 100

Shifts in Colonization Flora Clinical Infection

Clinical infection: Clinical infection may result in signs and  symptoms. Some of these may be less obvious or very • General shift towards Gram‐negative flora in hospitals, LTCF and minor. At the end of the spectrum is the individual with other health care facilities no sign, no symptoms who has a asymptomatic infection or subclinical infection. • Modification of the skin environment due to skin changes still poorly understood • Invasive procedures provides portal of entry to different flora Asymptomatic infection does not mean that “all is quiet”. It may cover some very active processes as in the • therapy: asymptomatic phase of HIV infection, • In a study of patients on ampicillin long term Rx, 90% colonized by infection, B carrier state. ampicillin‐resistant Enterobacteriae, controls only 10%

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True Infection NOT Colonization Sufficient Time to Develop Infection

• Infections are accompanied by signs and • diseases with specific incubation period: stay symptoms: in hospital  incubation period

•  , malaise

•  in localized infections: swelling due to • numerous infections do not have well set , heat, pain, erythema (tumor, dolor, incubation periods (for example, staphylococci, rubor, calor) E.coli infections) • Use definitions which establish minimum ‐ these infections rarely develop in less than characteristics for infection 2 days • NHSN criterion: Infection present after the 3rd 1 • Remember: Immunocompromised patients do hospital day (day of hospital admission is day not show signs of infection as normal patients. 3 1). Neutropenic patients (  500 neutrophils /mm3) show no pyuria, no purulent sputum, little infiltrate and no large consolidation on chest X‐ray

NO Infection at Time of Admission Methicillin‐Resistant

• establish prior negativity (MRSA)

• check history, symptoms and signs Colonization Infection • Approximately 30% of the • Occurs when a bacterial • documented at time of admission, lab tests population is colonized & chest X‐rays done strain undergoes with MRSA uncontrolled growth ‐normal physical examination • Organism lives on the skin • Can be localized to a ‐absence of for long periods of time specific area such as a generally in warm, damp, ‐normal chest X‐ray wound or spread dark areas of the body 2Excluded: ‐negative culture or lack of culture through the bloodstream •Transplacental • Nose infections Example: If urine cultures are collected at • Throat (bacteremia) •Reactivation of old day 7 of hospitalization and none • Armpits infections (ex Shingles) was collected before, it implies that no •Infections considered signs of infection were present in urine • “South of the border” extensions of infections before present at admission

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Vancomycin‐resistant Clostridium difficile (CDIFF) Enterococci (VRE)

Colonization Infection Colonization Infection • Asymptomatic • Presence of diarrheal • Acquired by susceptible • Weakened hosts have an • CDIFF is detected in the absence of symptoms of symptoms (3+ unformed hosts in an environment increased likelihood of infection stools in 24h) with a high rate of developing infection • The number of colonized • patient colonization with following colonization patients is higher than Stool tests positive for symptomatic CDI cases among CDIFF toxins or VRE, e.g. intensive care • PCR is used to detect hospital patients • Detection of toxigenic units, oncology units infections and outbreaks • Absence of diarrhea without CDIFF or colonoscopic histopathologic • Can lead to infection findings of • Colonoscopic findings pseudomembranous colitis demonstrating ulcerative depending on the health and colitis of the patient • Detection of CDIFF or • Presence of CDIFF toxins No tests of cure!!!!

Carbapenem‐resistant Urinary Tract Infections Enterobacteriacea (CRE) Colonization Infection • The of asymptomatic bacteriuria (ASB), bacterial • Organism can be found on • Cause infections when they colonization of the urinary tract without local signs or symptoms of the body but is not causing enter the body through infection, ranges from 23‐50% in non‐catheterized NH/SNF residents any symptoms or disease medical devices like central to 100% among those with long‐term urinary catheters. • Strains can go on to cause lines, urinary catheters, or • Differentiating ASB from symptomatic UTI can lead to inappropriate infections in sterile sites of wounds antibiotic use and its related complications. the body • Treatment options include • High prevalence of ASB and the challenges with diagnosing • Generally colonized in the GI tract tigecycline, colistin, and symptomatic UTI in NH/SNF residents have led to antibiotic overuse polymixin B in this population. • Overuse increases the likelihood of adverse events and complications of previous antibiotic treatment (e.g., CDI) along with emergence, transmission, and acquisition of MDROs. • Appropriate diagnosis and management of symptomatic UTI is a critically important issue in the NH/SNF setting.

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Urinary Tract Infections Testing Methods Summary

Organism Testing Indication Appropriate Specimen • Recommendations MRSA Wound infection with puss or Culture or molecular test • Do not text asymptomatic patients drainage of drainage • Urine is not sterile Clostridium difficile Diarrheal episodes of 3 or more Loose/watery stools that • Bacteria are present at low levels in the urine of healthy people stools in a consecutive 24h form to the shape of the not suffering from a period container CRE Depends on site of infection, but Varies depending on site Seek and ye shall find… generally aches, pain, fever of infection Inappropriate surveillance of urinary Appropriate surveillance of urinary tract VRE Back pain, trouble urinating, Culture of peri‐rectal/anal tract infections infections fever, chills, body aches; swabs or stool specimens red/warm wound with swelling Screening all patients’ urine, regardless Test the urine of symptomatic persons and drainage of presence of symptoms, upon admit to (fever, dysuria, frequency, etc.) that you the facility. If organisms are identified, suspect have urinary tract infections. MDRSP Fever, chills, sweats, aches and Urine or sputum Gram you will be compelled to treat people pains, headache, malaise stains or antigen tests – who are not experiencing disease. likely to be coordinated by an acute care hospital

Multidrug‐resistant Streptococcus Transferring patients to other pneumoniae (MDRSP) facilities • Implement systems to Colonization Infection designate patients • Asymptomatic • Causes invasive diseases known to be colonized nasopharyngeal such as sepsis, or infected with a colonization , and targeted MDRO pneumonia • Notify receiving healthcare facilities and personnel prior to • Resistant to penicillin and other broad‐spectrum agents such as transfer of such macrolides and fluroquinolones patients within or • Prevention is primarily through Pneumococcal vaccines against the between facilities bacteria Streptococcus pneumoniae

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General recommendations for Summary all healthcare settings • Make MDRO prevention and control an organizational patient • Infection means that germs are in or on the body and make safety priority you sick, which results in signs and symptoms such as fever, • Implement systems to communicate information about pus from a wound, a high white blood cell count, diarrhea, or reportable MDROs to state public health authorities pneumonia. • Support participation of the facility in coalitions to combat • Colonization means germs are on the body but do not make emerging or growing MDRO problems you sick. People who are colonized will have no signs or • Provide education and training on risks and prevention of symptoms. MDRO transmission during orientation and periodic • Judicious surveillance and screening practices are essential to educational updates for healthcare personnel antibiotic stewardship • Monitor susceptibility reports • Although MDROs cause concern, they may be managed appropriately across a spectrum of provider types

Patient Placement in LTCFs References

• When single‐patient rooms are available, assign priority for • Bogaert D, De Groot R, and Hermans PW. Streptococcus these rooms to patients with known or suspected MDRO pneumoniae colonisation: the key to pneumococcal disease. Lancet Infect Dis. 2004 Mar;4(3):144‐54. colonization or infection • Centers for Disease Control and Prevention. Carbapenem‐resistant • Give highest priority to these patients who have conditions Enterobacteriaceae (CRE) infection: clinician FAQs. Accessed 24 Jan that may facilitate transmission, e.g. uncontained secretions 2017. Available at https://www.cdc.gov/hai/organisms/cre/cre‐ or excretions clinicianfaq.html. • Centers for Disease Control and Prevention. Prevention of • When single‐patient rooms are not available, cohort patients transmission of multidrug resistant organisms. Accessed 24 Jan with the same MDRO in the same room or patient‐care area 2017. Available at https://www.cdc.gov/hicpac/mdro/mdro_5.html. • When cohorting patients with the same MDRO is not possible, • Luis F‐K et al. Asymptomatic Clostridium difficile colonization: place MDRO patients in rooms with patients who are at low and clinical implications. BMC Infect Dis. 2015;15:516. risk for acquisition of MDROs and associated outcomes from • Zirakzadeh A and Patel R. Vancomycin‐resistant enterococci: infection and are likely to have short lengths of stay colonization, infection, detection, and treatment. Mayo Clin Proc. 2006 Apr;81(4):529‐36.

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