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The Fecal Veneer – Part 2

18 May

So, GNB colonization of the respiratory tract is possible.  Why do these pathogens that normally like to live in the GI tract move and end up in our mouths and respiratory tracts?  An amazing review by Curtis Donsky provides the basis for this blog entry. (1).

The answer is all in the doo doo. The human colon contains as many as 1 trillion (1,000,000,000,000) bacteria per gram.  This massive reservoir of bacteria from the GI tract is the source of the “fecal veneer” on hospital surfaces and the skin of patients. The fecal veneer (or fecal patina if you’re fancy) is the theory that the world is covered in a thin layer of stool.

In our hospitalized patients, imagine a bull’s eye of bacteria from the rectum that gradually grows with decreased hygiene and is aided by iatrogenic causes. (2) This army of bacteria spreads in all directions and can eventually reach the mouth.  Fecal incontinence , diarrhea, altered mental status, and debilitation also could potentially contribute to this. Patients are touched and moved often.  We use various instruments that come in contact with the environment and the patient.  Patient’s are not able to shower, their linens aren’t changed often. You get the picture.

Add to this antibiotics, and acid suppression that can interrupt our natural colonization resistance.  Colonization resistance is our natural and diverse makeup of bacteria which prevents pathogens from taking over. Below is a figure from Donsky’s paper which is a great summary.

There are other cans where the veneer originates.  While training during rounds, a former truck driver and ID physician went on a rant that toilets were like bacterial volcanoes when flushed spewing and aerosolizing #1s and #2s into the environment.  I didn’t believe the kooky ID man.  He was right.  Lidless toilets can aerosolize C difficile and other pathogens.(3,4) Best used faecal suspensions of C diff and sampled air, and measured surface contamination.  Adding a lid to the toilet eliminated the surface contamination (luckily our ICU has lidded toilets).

This micro thin patina can’t be avoided.  Although it can’t be seen or smelled, it most definitely exists. As a patient’s length of stay increases the interactions with potentially contaminated instruments and hands of healthcare workers increases.

It’s easy to see how a patient  can be colonized now with the doo doo.  This can happen either directly (from the environment of the patient) or indirectly (by healthcare worker’s hands and equipment).   Hopefully this highlights the importance of hand hygiene and initiatives like chlorhexidine baths (5,6). Back to the cases, antibiotics were started on both patients.   We used a short course of 3 days in one of the patients.   (7).

We do a yearly boys weekend camping trip.  Showers are a luxury that aren’t afforded. By the end of the weekend I feel pretty filthy and just want a shower.  I wonder if this is what my patina feels like.

Don’t you want to sterilize your desk and wash your hands?

[1] Donskey, C. J. (2004). The role of the intestinal tract as a reservoir and source for transmission of nosocomial pathogens. Clinical Infectious Diseases, 39(2), 219-226. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/15307031

[2] Williams, L. (2012). Intensive care unit environments and the fecal patina: A simple problem? Critical Care Medicine, 40(4), 1333-1334. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/22425825

[3] Best, E. L., Sandoe, J. A. T., & Wilcox, M. H. (2012). Potential for aerosolization of Clostridium difficile after flushing toilets: the role of toilet lids in reducing environmental contamination risk. The Journal of hospital infection, 80(1), 1-5. Retrieved from http://dx.doi.org/10.1016/j.jhin.2011.08.010

[4] Barker, J., & Jones, M. V. (2005). The potential spread of infection caused by aerosol contamination of surfaces after flushing a domestic toilet. Journal of Applied Microbiology, 99(2), 339-347. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/16033465

[5] Bleasdale, S. C., Trick, W. E., Gonzalez, I. M., Lyles, R. D., Hayden, M. K., & Weinstein, R. A. (2007). Effectiveness of chlorhexidine bathing to reduce catheter-associated bloodstream infections in medical intensive care unit patients. Archives of Internal Medicine, 167(19), 2073-2079. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/17954801

[6] Climo, M. W., Sepkowitz, K. A., Zuccotti, G., Fraser, V. J., Warren, D. K., Perl, T. M., Speck, K., et al. (2009). The effect of daily bathing with chlorhexidine on the acquisition of methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and healthcare-associated bloodstream infections: results of a quasi-experimental multicenter trial. Critical Care Medicine, 37(6), 1858-1865. Society of Critical Care Medicine and Lippincott Williams & Wilkins. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19384220

[7] Singh, N., Rogers, P., Atwood, C. W., Wagener, M. M., & Yu, V. L. (2000). Short-course empiric antibiotic therapy for patients with pulmonary infiltrates in the intensive care unit. A proposed solution for indiscriminate antibiotic prescription. American Journal of Respiratory and Critical Care Medicine. Am Thoracic Soc. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/10934078

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Respiratory tract colonization with GNB Part 1

18 May

 It’s been a crazy last few months, we’ve been busy with many side projects with ASP.  Dan and I have been adding to our list of blog topics. I’m looking forward to Dan’s planned post on ‘why fluoroquinolones are evil.’

This is a 2 part post. The topic of this post comes from two recent interactions we had with our colleagues.  Two cases (two different hospitals) of suspected ICU HAP/VAP with gut/poo bacteria (Klebs + E coli).  Both patients grew these bugs from sputum cultures and the comment was made that these must be pneumonias because you can’t be colonized with poo in your respiratory tract.

A paper by Johanson et. al published in the New England Journal of Medicine in 1969[1] provides a great starting point to this discussion.  The group from Texas selected 5 groups of adults: non-hospitalized normal subjects (members of Dallas fire dept); hospital associated normal subjects (hospital staff); physically normal hospitalized patients (psych ward); moderately ill hospitalized patients (ortho); and near death (moribund) patients (critically ill medical).  They obtained oropharyngeal cultures from each of the groups.  They found that 57% of moribund patients were colonized with gram negative bacilli (GNB) and 16% of moderately ill patients (orthopedic) were colonized.  2% from the non-hospitalized normal subjects were also colonized.  This was a small study, and has its flaws.  There are other papers that explore colonization with GNBs.  (2,3,4)   It is possible to have poo bacteria in the mouth/oropharynx. 

In normal hosts >90% of GNB in the oropharynx is cleared by effective salivary flow and swallowing.  (5) Our sicker and elderly patients have impairment of these clearance mechanisms thus the increased risk of colonization by pathogenic GNBs. 

But how do GNBs get into the mouth/oropharynx to begin with? The answer is pretty wild.


[1]Johanson, W. G., Pierce, A. K., & Sanford, J. P. (1969). Changing pharyngeal bacterial flora of hospitalized patients. Emergence of gram-negative bacilli. The New England Journal of Medicine, 281(21), 1137-1140.

 [2] Garrouste-Orgeas, M., Chevret, S., Arlet, G., Marie, O., Rouveau, M., Popoff, N., & Schlemmer, B. (1997). Oropharyngeal or gastric colonization and nosocomial pneumonia in adult intensive care unit patients. A prospective study based on genomic DNA analysis. American Journal of Respiratory and Critical Care Medicine, 156(5), 1647-1655. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/9372689

[3] Heyland, D., & Mandell, L. A. (1992). Gastric colonization by gram-negative bacilli and nosocomial pneumonia in the intensive care unit patient. Evidence for causation. Chest, 101(1), 187-193.

[4] Mackowiak, P. A., Martin, R. M., Jones, S. R., & Smith, J. W. (1978). Pharyngeal colonization by gram-negative bacilli in aspiration-prone persons. Archives of Internal Medicine, 138(8), 1224-1227.

[5] Palmer, L. B., Albulak, K., Fields, S., Filkin, A. M., Simon, S., & Smaldone, G. C. (2001). Oral clearance and pathogenic oropharyngeal colonization in the elderly. American Journal of Respiratory and Critical Care Medicine, 164(3), 464-468. Retrieved from http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=11500351