Monday, 25 December 2017

Yersinia enterocolitica: Diarrhoea causative agent

Yersinia enterocolitica is a Gram negative rod-shaped bacterium in the family of Enterobacteriaceae known as causative agent of gastrointestinal infections and most often causes the disease yersiniosis with a variety of symptoms such as enterocolitis, acute diarrhea, terminal ileitis and pseudoappendicitis but, if it spreads systemically, can also result in fatal sepsis. The genus Yersinia includes 11 species: Y. pestis, Y. pseudotuberculosis, Y. enterocolitica, Y. frederiksenii, Y. intermedia, Y. kristensenii, Y. bercovieri, Y. mollaretii, Y. rohdei, Y. aldovae, and Y. ruckeri. Among them, only Y. pestis, Y. pseudotuberculosis, and certain strains of Y. enterocolitica are of pathogenic importance for humans and certain warm-blooded animals, whereas the other species are of environmental origin and may, at best, act as opportunists. However, Yersinia strains can be isolated from clinical materials, so have to be identified at the species level.
Signs and symptoms
Symptoms of Y. enterocolitica infection typically include Diarrhea which is the most common clinical manifestation of this infection; diarrhea may be bloody in severe cases, low grade fever, abdominal pain, vomiting. The patient may also develop erythema nodosum, which manifests as painful, raised red or purple lesions, mainly on the patient’s legs and trunk. Lesions appear 2-20 days after the onset of fever and abdominal pain and resolve spontaneously in most cases in about a month.
Y. enterocolitica infection can be diagnosis by a number of methods which includes Stool culture - This is the best way to confirm a diagnosis of Y. enterocolitica. The figure above shows the growth of Y. enterocolitica on CIN (Cefsulodin, Irgasan, Novobiocin) Agar. The characteristic deep red center with a transparent margin, or "bull's-eye" appearance of Yersinia andAeromonas colonies is important for identification, and is due to the presence of mannitol. Y. enterocolitica ferments the mannitol in the medium, producing an acid pH which gives the colonies their red color and the "bull's eye" appearance. Sodium deoxycholate, cefsulodin, irgasan, and novobiocin are added as selective agents. Altorfer found that by reducing the concentration of cefsulodin from 15.0 to 4.0mcg/ml, CIN Agar could also be used to selectively isolate Aeromonas spp., in addition to Yersinia.
Other diagnosis methods include tube agglutination, Enzyme-linked immunosorbent assays
Radioimmunoassays, Imaging studies - Ultrasonography or computed tomography (CT) scanning may be useful in delineating true appendicitis from pseudoappendicitis, Colonoscopy - Findings may vary and are relatively nonspecific, Joint aspiration in cases of Yersinia- associated reactive arthropathy
Care in patients with Y enterocolitica infection is primarily supportive, with good nutrition and hydration being mainstays of treatment
First-line drugs used against the bacterium include the following agents:
Third-generation cephalosporins
Trimethoprim-sulfamethoxazole (TMP-SMZ)
Fluoroquinolones - not approved for use in children under 18 years

Sunday, 27 August 2017

Global Shortage of Hepatitis B Vaccine - PHE

Image result for hepatitis b vaccine
There is currently a global shortage of hepatitis B vaccine which has been caused by problems in the manufacturing process.
Public Health England, working with NHS England, the Department of Health and the manufacturers, have put in place a series of measures so that the NHS and other providers can use the available vaccine for those at highest immediate risk. Measures are expected to continue until the beginning of 2018 and will be kept under review.
The risk of catching hepatitis B infection in the UK is very low.
In the UK, vaccination is usually offered to individuals who are at specific risk of being exposed to blood from an infected person. This includes babies born to mothers who are infected with hepatitis B, the sexual partners of infected individuals and a range of other groups such as men who have sex with men, healthcare workers, and people who inject drugs. Vaccination is also recommended for people who will be undertaking certain activities overseas.
A course of hepatitis B vaccine usually involves 3 doses of vaccine, completed over a few months. While supplies are limited, vaccine will be prioritised for those at highest immediate risk based on their doctor’s assessment. For other people, a doctor may advise that hepatitis B vaccine can be deferred until later.
Hepatitis B virus is found in the blood and bodily fluids, such as semen and vaginal fluids, of an infected person. It cannot be spread by kissing, holding hands, hugging, coughing, sneezing, or sharing crockery and utensils.
Individuals can reduce their risk of contracting hepatitis B by taking care to:
·         avoid having unprotected sex
·         not inject drugs, or by not sharing needles when injecting
·         avoid having tattoos, piercing or acupuncture when overseas
·         avoid accessing medical or dental care in high prevalence countries
Vaccination will still be available, as now, for those who have already been exposed to hepatitis B. Such people should seek urgent medical attention as the infection can still be prevented if treated promptly after the incident.
The recently announced addition of hepatitis B protection to the routine childhood immunisation programme at 2, 3 and 4 months will go ahead. The combined vaccine, which protects against hepatitis B and 5 other diseases, is not affected by this shortage.

Long term hepatitis B infection can be symptomless and people who think they may have acquired the infection in the past should seek a test from their healthcare professional.


Sunday, 15 January 2017

Killer Superbug: Pan-Resistant New Delhi Metallo-Beta-Lactamase-Producing Klebsiella pneumoniae

Image result for cdc
On August 25, 2016, the Washoe County Health District in Reno, Nevada, was notified of a patient at an acute care hospital with carbapenem-resistant Enterobacteriaceae (CRE) that was resistant to all available antimicrobial drugs. The specific CRE, Klebsiella pneumoniae, was isolated from a wound specimen collected on August 19, 2016. After CRE was identified, the patient was placed in a single room under contact precautions. The patient had a history of recent hospitalization outside the United States. Therefore, based on CDC guidance, the isolate was sent to CDC for testing to determine the mechanism of antimicrobial resistance, which confirmed the presence of New Delhi metallo-beta-lactamase (NDM).
The patient was a female Washoe County resident in her 70s who arrived in the United States in early August 2016 after an extended visit to India. She was admitted to the acute care hospital on August 18 with a primary diagnosis of systemic inflammatory response syndrome, likely resulting from an infected right hip seroma. The patient developed septic shock and died in early September. During the 2 years preceding this U.S. hospitalization, the patient had multiple hospitalizations in India related to a right femur fracture and subsequent osteomyelitis of the right femur and hip; the most recent hospitalization in India had been in June 2016.
Antimicrobial susceptibility testing in the United States indicated that the isolate was resistant to 26 antibiotics, including all aminoglycosides and polymyxins tested, and intermediately resistant to tigecycline (a tetracycline derivative developed in response to emerging antibiotic resistance). Because of a high minimum inhibitory concentration (MIC) to colistin, the isolate was tested at CDC for the mcr-1 gene, which confers plasma-mediated resistance to colistin; the results were negative. The isolate had a relatively low fosfomycin MIC of 16 μg/mL by ETEST. However, fosfomycin is approved in the United States only as an oral treatment of uncomplicated cystitis; an intravenous formulation is available in other countries.
A point prevalence survey, using rectal swab specimens and conducted among patients currently admitted to the same unit as the patient, did not identify additional CRE. Active surveillance for multidrug-resistant bacilli including CRE has been conducted in Washoe County since 2010 and is ongoing; no additional NDM CRE have been identified.

The BBC Health described that the analysis found the superbug was resistant to all 26 available antibiotics in the US including the "drug of last resort" - colistin.

Tuesday, 5 July 2016

E.coli O157 Outbreak Linked to Contaminated Mixed Salad Leaves in England

Hands being washed under running water.
There is an Escherichia coli (E. coli) outbreak affecting more than 100 UK people could be linked to eating contaminated mixed salad leaves according to public health England. To date, 109 people (figure correct as at 4 July 2016) are known to have caught the bug - 102 in England, 6 in Wales and 1 in Scotland with the South West of England particularly affected.
PHE has been working to establish the cause of the outbreak and has now identified that several of the affected individuals ate mixed salad leaves including rocket leaves prior to becoming unwell. Currently, the source of the outbreak is not confirmed and remains under investigation. PHE is now reminding people to maintain good hygiene and food preparation practices in response to the current outbreak.
E. coli O157 infection can cause a range of symptoms, from mild diarrhoea to bloody diarrhoea with severe abdominal pain. On rare occasions, it can also cause more serious medical conditions and can be caught by eating contaminated food or by direct contact with animals with the bacteria. It can also be passed from an infected individual to another person if hand and toilet hygiene is poor.
Dr Isabel Oliver, director of PHE's field epidemiology service, said: "At this stage, we are not ruling out other food items as a potential source."
PHE was first alerted to the outbreak at the end of June. Dr Oliver said people could help protect themselves from possible infection by washing their hands before eating and handling food and by thoroughly washing vegetables and salads that they were preparing to eat.
E. coli O157 is found in the gut and faeces of many animals, particularly cattle, and can contaminate food and water. Outbreaks of E. coli O157 are rare compared with other food-borne diseases.
Avoiding E. coli O157 infection
§  Wash hands thoroughly after using the toilet, before and after handling food, and after handling animals
§  Remove any loose soil before storing vegetables and salads
§  Wash all vegetables and fruits that will be eaten raw
§  Store and prepare raw meat and unwashed vegetables away from ready-to-eat foods
§  Do not prepare raw vegetables with utensils that have also been used for raw meat
§  Cook all minced meat products, such as burgers and meatballs, thoroughly

§  People who have been ill should not prepare food for others for at least 48 hours after they have recovered

Source - PHE & BBC

Sunday, 17 April 2016

Concerns over the spread of untreatable multi-antimicrobial resistant gonorrhoea strain

There is a huge concern by health sector and Doctors in England over wide spread of untreatable multi-antimicrobial resistant gonorrhoea strain widely across England and to gay men.
The new superbug prompted a national alert last year shared in this blog (Read it here), as one of the main treatments had become useless against it. Public Health England acknowledges measures to contain the outbreak have been of limited success.
Doctors fear the sexually transmitted infection, which can cause infertility, could soon become untreatable. There are now cases of this resistant gonorrhoea in the West Midlands, London and southern England. Only 34 cases have been officially confirmed in laboratory testing, but this is likely to be the tip of the iceberg of an infection that can be symptomless.
The outbreak started in straight couples, but is now being seen in gay men too. A consultant in sexual health based in Bristol, Peter Greenhouse said that we’ve been worried it would spread to men who have sex with men which is what we have now. The problem is that they tend to spread infections a lot faster simply as they change partners more quickly. They are also more likely to have gonorrhoea in their throats. Further resistance is more likely to develop as antibiotics get to the throat in lower doses and the area is also teeming with other bacteria that can share the resistance to drugs.
The bacterium that causes gonorrhoea is extremely adept at shrugging off our best antibiotics. Two drugs - azithromycin and ceftriaxone - are used in combination, but now resistance to azithromycin is spreading and doctors fear it is only a matter of time before ceftriaxone fails too.

The disease is caused by the bacterium called Neisseria gonorrhoeae and infection is spread by unprotected vaginal, oral and anal sex. Of those infected, about one in 10 heterosexual men and more than three-quarters of women, and gay men, have no easily recognisable symptoms. But symptoms can include a thick green or yellow discharge from sexual organs, pain when urinating and bleeding between periods.
Untreated infection can lead to infertility, pelvic inflammatory disease and can be passed on to a child during pregnancy.


Polio Vaccination: Vaccine switched in a bid towards ending polio

Over 150 countries have begun switching to a different polio vaccine which has been hailed by health campaigners as an important milestone towards polio eradication. The new vaccine will target the two remaining strains of the virus under a switchover 18 months in the planning. There were just 74 cases of the paralysing disease in 2015 and there have been 10 so far this year. All of the cases were in Afghanistan and Pakistan. Africa has been free of polio for more than a year. Switching the vaccine from one successfully used to fight polio for more than 30 years is a huge logistical exercise.
Thousands of people will monitor the changeover in 155 countries during the next fortnight. It is taking effect mainly in developing countries, but also in richer ones such as Russia and Mexico. The new vaccine will still be given as drops in the mouth, so healthcare workers will not need fresh training. It will no longer include a weakened version of type 2 polio virus, which was eradicated in 1999.
Dr Stephen Cochi, from the US-based Centers for Disease Control (CDC), said that the current vaccine contains live weakened virus relating to three types of polio. But we don't need the type 2 component, as it's not in the world any longer. And in very rare cases it can mutate and lead to polio, through what's called circulating vaccine-derived virus. So removing type 2 from the vaccine takes away that risk - and ensures we have a vaccine which will work better dose by dose.
The planning involved in the switchover has included dealing with a global stockpile of 100 million doses of vaccine targeting just type 2, built up as an insurance policy in case of any outbreak. The World Health Organization denied some media reports that millions of doses of the old vaccine would need to be destroyed, by incineration or other approved means. Its director of polio eradication, Michel Zaffran, said some will need to be destroyed, but this will be a few vials, not trucks full of vaccine. This has been carefully planned because of the huge amount of resources, so countries have been using up the old vaccine, to minimise leftover quantities. We're closer than ever to ending polio worldwide, which is why we are able to move forward with the largest and fastest globally synchronised vaccine switchover.


Sunday, 10 April 2016

PHE Update on rising Scarlet Fever across England

Group A streptococcus (GAS) on Blood Agar
Following the Public Health England (PHE) warning on the rise in cases of scarlet fever in England, they have reported a continued increase in cases of scarlet fever across England with 1319 new cases between 21 to 27 March. This is the highest weekly total recorded in recent decades (data available from 1982 onwards). Since the season began in September 2015, there have been a total of 10,570 reported cases of scarlet fever. Scarlet fever is a seasonal illness which should be treated with antibiotics and cases of the illness usually peak at this time of year.
An increase in invasive disease caused by the same bacterium Group A streptococcus (GAS) which causes scarlet fever has also been seen in England. A total of 593 cases of invasive Group A streptococcus infection, such and bloodstream infection or pneumonia, have been notified so far for 2016 compared to 440 cases for the same period last year (January to March). Group A streptococcus seasonal activity this year coincides with the seasonal influenza activity owing to the late flu season. Influenza and invasive Group A streptococcus co-infection is a rare but well-recognised occurrence. Whilst the elderly remain most at risk of invasive Group A streptococcus infection, increased levels of disease compared to last year have been seen in young adults and children less than 5 years old, the age groups most affected by influenza in recent weeks. There’s no suggestion of an increase in invasive Group A streptococcus infection in patients diagnosed with scarlet fever.
This is the third season in a row in which elevated scarlet fever activity has been noted. A total of 15,637 notifications were made in England and Wales in 2014, rising to 17,590 in 2015. Weekly activity so far this season has been similar or slightly above for that last year.
Group A streptococcus bacteria are spread by direct person-to-person contact with an individual carrying the bacteria or indirectly through contact with bacteria in the environment. The act of keeping wounds clean and practising hand hygiene can decrease chances of catching a Group A streptococcus infection.
Dr Theresa Lamagni, PHE’s head of streptococcal infection surveillance, said that while we hope that the Easter school break will assist in slowing down transmission of the bacteria causing scarlet fever, we cannot assume or rely on this being the case. As such, our investigations and assessment of the impact of this extraordinary rise in scarlet fever continue.
As we reach peak season for scarlet fever, health practitioners should be particular mindful of the current high levels of scarlet fever when assessing patients. Close monitoring, rapid and decisive response to potential outbreaks and early treatment of scarlet fever with an appropriate antibiotic remains essential, especially given the potential complications associated with Group A streptococcal infections. PHE strongly urges people with symptoms of scarlet fever, which include a sore throat, headache and fever accompanied by a characteristic rash, to consult their GP. Scarlet fever should be treated with antibiotics to reduce risk of complications. Once children or adults are diagnosed with scarlet fever we strongly advise them to stay at home until at least 24 hours after the start of antibiotic treatment to avoid passing on the infection.
Scarlet fever is mainly a childhood disease and is most common between the ages of 2 and 8 years. It was once a very dangerous infection, but has now become much less serious, thanks to the use of antibiotics. There is currently no vaccine for scarlet fever.
Below is the PHE regional breakdowns for scarlet fever seasonal activity in England between September and March (for 2014 to 2015, and 2015 to 2016; weeks 37 to 13)
Scarlet Fever Notifications
2014 – 2015 (weeks 37 – 13
2015 – 2016 (weeks 37 - 13)
Area name
Anglia and Essex
Avon, Gloucestershire and Wiltshire
Cheshire and Merseyside
Cumbria and Lancashire
Devon, Cornwall and Somerset
East Midlands
Greater Manchester
Kent Surrey and Sussex
North East
South Midlands and Hertfordshire
Thames Valley
West Midlands
Yorkshire and Humber
Grand Total