Probable Person-to-Person Transmission of Legionella

Schermafbeelding 2016-03-04 om 00.40.08

Ana M. Correia and colleagues (N Engl J Med 374;5 February 4, 2016) present a convincing case of person-to-person transmission of Legionnaires’ disease between son and mother. Seen the epidemiology of the two cases and the results of whole-genome sequencing, the only part of the short report I do not understand is the “probable” in the title. I wouldn’t know what else to include in order to call it “proven”.

Consequently, the question is whether this “new” transmission route has implication for infection control in the hospital setting. The mother had very close contact over an extended amount of hours with her severely coughing son, in a small and badly ventilated room. In opposite to HCWs who in this situation generally would wear a mask, she obviously used no personal protective equipment. Finally, while described as formerly healthy, no further details are given about the conditions possibly increasing the susceptibility of the 74-year old to Legionella.

Thus, while person-of-person transmission seems proven in the present case, I believe that the circumstances are unique and don’t require to change the present infection control measures taken in patients with Legionnaires disease.

Everything is in place.. so that’s alright then

8465992771_213dabc72c_zI am always interested in compliance. What makes staff implement an intervention reliably? What makes a patient follow the advice they’ve been given? A new retrospective cohort study purports to look at what factors influence compliance with preoperative regimes aimed at preventing surgical site infection (SSI). The authors were of the opinion that socio-economic group would be a major factor in whether individuals would be compliant with measures that are likely to reduce the risk of SSI, since this has been demonstrated to be the case in chronic health issues such as asthma. Disappointingly the authors stated that the method of determining at adherence is described elsewhere with the accompanying reference to an 4-minute abstract given at a paediatric orthopaedic conference in Toronto in 2013 which, if you weren’t there, you’ve missed it. However they do provide a small amount of detail and of the 2-5 protocol tasks they only mention bathing and decolonisation of those screened.

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Are spores the secret of the success of FMT in treating recurrent CDI?

Characteristic of the aimes strain of b anthracis is the smooth

I have been following the literature around the use of faecal microbiota transplantation (FMT) for the treatment of recurrent Clostridium difficile infection (CDI). FMT is spectacularly effective but rather crude – and may have some associated risks, not least the possibility of transmissing infectious organisms we have not yet discovered! There is also the issue of administration. Compared with recurrent CDI, a duodenal infusion (aka tube up the backside) isn’t so bad – but an oral delivery would be preferable. The ‘crapsule’ (oral FMT) has been tested and is effective, but it requires a large number of crapsules to reach the required dose. So, the search is on to distill the effective elements of FMT into a format that can be delivered more easily. Some work has been done on exploring various combinations of live bacteria – with variable success.

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Review on AMR: progress to date

amr review

Like many others, I am keeping a close eye on the UK Government’s commissioned ‘Review on AMR’. The Review team have been tremendously productive over the last few years, already releasing detailed reports on:

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Colistin resistance in CPE: an emerging threat

colistin structure

I am becoming increasingly interested in colistin resistance in CPE, not least because of this work that we will be presenting on colistin resistance in CPE at ECCMID in a few months time. I have been brushing up on how colistin resistance occurs in CPE, and why it is important, so thought I’d share my findings. I started with a pubmed search for “colistin resistance mechanism” on 12/02/16 and this is what I found (85 hits from the initial search):

Colisin

Colistin is an old class (discovered during WWII) of cationic antibiotic. Colistin (polymyxin E) is a polypeptide bactericidal agent and is one of the two clinically available forms of polymyxin agents (polymyxin B and polymyxin E). Colistin interacts with lipopolysaccharide in the outer membrane, resulting in a leaky and ultimately dead bacterial cell.1 Issues with presumed nephrotoxicity have kept colistin very much on the top shelf, but the emergence of CPE has brought colistin down a shelf or two – and we are learning that the nephrotoxicity tradionally associated with colisin may not be so bad afterall.1

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Antibiotic surgical prophylaxis: stewardship’s ‘elephant in the room’?

Doxycycline_100mg_capsules

We are all pretty comfortable with the idea that we have used too many antibiotics in the past and now we are reaping the consequences. I think we are also all in agreement that we need to start using antibiotics much more rationally – and keep the big guns firmly on the top shelf, double-wrapped in password-protected packaging that you can only access with a fingerprint and retinal scan (whilst acknowledging that they will still somehow be prescribed by a junior doctor at 3am for a sniffle). But I get the feeling that we all have a bit of a blind spot (or soft spot) for surgical prophylaxis. Here, the situation is different, surely, because the consequence of an SSI is so great that the likely ‘cost’ of widespread surgical prophylaxis is outweighed by the gain of fewer SSIs? But has this become stewardship’s elephant in the room? We are comfortable talking about restricting carbapenem use in acute hospitals, but I don’t hear as much discussion about stopping the use of antibiotics for surgical prophylaxis! On one level, isn’t this is the same arguments as for ‘selective’ digestive or oral decontamination (SDD / SOD) in the ICU? Here, the argument in factor of SDD / SOD is compelling: fewer deaths and less spread of resistant bacteria. But indiscriminate use of antibiotics, which is bound to fuel antibiotic resistance in the long run, just cannot be a good idea, particularly in the high-risk ICU population.

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CRISPR-Cas “surgical strikes” against antibiotic-resistant bacteria

surgical strike

We are in desperate need of antibiotic-sparing approaches to antibacterial therapy. Antibiotic resistance is increasing, and we are becoming increasingly aware of the impact of antibotics on the microbiota. I blogged a while ago about CRISPR-Cas systems being used to tackle antibiotic-resistant bacteria on surfaces. But the same approach could be applied to treating human infections.

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Community MRSA preys on the poor and deprived

deprivation mrsa

As you can probably tell from the title, this post comes with a warning: it presents some rather “un-PC” data, but I’ll do my best to deliver it calmly and dispassionately! My old research team from KCL have just published a paper in PLOS Medicine on the association between social and material deprivation, and MRSA.

I’ve been interested in the dynamic between hospital-associated (HA) and community-associated (CA) MRSA for years (not least because it was the subject of my PhD thesis). I wrote a review several years ago on how community MRSA should be seen as a genotypic phenomenon with epidemiological implications. Using this framework, it is possible to get your head around CA strains of MRSA beginning to cause hospital-acquired infections. The aim of this study was to use a large collection of MRSA from across several regions of London to explore the transmission dynamics and epidemiological associations of HA and CA types of MRSA.

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3.. 2.. 1.. Zero. Great, the 48 hours are up!

Slide1We often see those tasked with finding suitable isolation facilities counting down to when precaustions can be discontinued and the ’48 hours clear’ of symptoms of loose stools or vomiting has almost become one of the most welcome statements heard in healthcare settings. No more contact precautions, no more disinfectants sloshing around, normality beckons.. Or should it? Continue reading

Norovirus: to close or not to close?

Noroviruses belong to the genus norovirus and the family caliciv

The Journal of Infectious Diseases has just published a special issue on norovirus, which is well worth reading. When norovirus strikes, there is an inclination to close the ward to new admissions at the earliest available opportunity in order to protect incoming patients. But when should the ward closure trigger be pulled? Not at all, as recommended by latest UK guidelines (risking continuation of the outbreak, fed by a steady stream of new victims…I mean admissions), when you get a single case of vomiting or diarrhoea (lots of unnecessary ward closure) or only when you have a lab confirmed outbreak on your hands (by which time the horse has already bolted and galloped through your hospital). The special issue included a useful modelling study providing some idea of the impact of various approaches to ward closure in response to noro outbreaks.

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