Antibiotics no longer deliver KO punch

Clusters of drug-resistant bacteria. It is estimated that several thousand cases of such resistance occur in Singapore annually.
Clusters of drug-resistant bacteria. It is estimated that several thousand cases of such resistance occur in Singapore annually.PHOTO: DEPARTMENT OF MICROBIOLOGY, SINGAPORE GENERAL HOSPITAL

Common infections increasingly becoming untreatable, says UN

A young leukaemia patient developed high fever after she had a bone marrow transplant and chemotherapy. Within a week, the bacteria in her blood became resistant to all commonly used antibiotics.

In another case, a middle-aged Singaporean, who had never been warded in hospital, underwent a prostate biopsy. Doctors gave him commonly used antibiotics after he developed a high fever and multiple organ failure but they did not work.

Infectious diseases experts said such cases of antibiotic resistance have become more common. There are several thousand cases a year here, according to one estimate.

Of particular concern is a group of bacteria that has shown resistance to a class of antibiotics called Carbapenems. These drugs are the last effective and safe options available for such infections.

Called gram negative bacteria, they commonly live in the gut and can cause urine infections and other infections in the abdomen and pelvis.

While Carbapenems used to be able to treat these infections, doctors are now seeing more patients who do not seem to get better with these drugs.

  • Overuse, misuse cause resistance

  • Q What is antimicrobial resistance and how does it develop?

    A Antimicrobial resistance refers to the ability of microbes such as bacteria and viruses to resist the effects of medicines that were previously able to kill them. These microbes develop resistance to antimicrobial medicines when they are overused or misused.

    According to Dr Asok Kurup, an infectious diseases specialist at Mount Elizabeth Hospital, patients show symptoms of antibiotic resistance which can vary according to the site of infection.

    These organisms can cause all kinds of infections including pneumonia as well as urinary tract and bloodstream infections. Those at risk include the very young and old, those who were recently in hospital, had surgery or antibiotic therapy, as well as critically ill patients.

    "However, some patients... may be asymptomatic. There are very limited therapeutic alternatives other than last-line agents," said Dr Kurup.

    These are drugs that are typically tried after all other drug options have failed.

    "There are some specific interventions possible in difficult cases where all lines of treatment fail. And unfortunately yes, if all fail, patients can die from serious infections."

    According to the World Health Organisation, examples of antibiotic misuse include when the medicines are taken by people with viral infections like colds and flu, and when they are given as growth promoters for animals and fish.

    Bacteria that have become resistant to antibiotics - including those found in livestock - can also pass their resistance genes to others in the gut once the meat is consumed, especially if it is not cooked properly.

    A study published last year by students from the Yong Loo Lin School of Medicine at the National University of Singapore, with public health experts from the National University Health System, found that one-third of patients from the study expected antibiotics to be prescribed by general practitioners for common ailments like cough, sore throat and a runny or blocked nose, although such symptoms are caused mainly by viruses.

    Antibiotics are effective only for infections caused by bacteria and are useless against viruses.

    The study involved 914 adult patients from 24 GP clinics across Singapore.

    It also found that half of those expecting antibiotics would ask their doctors to prescribe the medication or would see another doctor if antibiotics were not prescribed.

    Carolyn Khew

A recent study showed that about 7 per cent of Enterobacteriacea - a family of gram negative bacteria - in Singapore hospitals were resistant to Carbapenems, said Dr Asok Kurup, an infectious diseases specialist at Mount Elizabeth Hospital.

"Singapore has a significant antimicrobial resistance problem, being a travel and a medical hub.

"This problem has been worsening in recent years especially with a group of germs called the gram negative organisms," he added.

Antimicrobial resistance has been flagged as a serious concern worldwide. It happens when antibiotics are overused or misused and microbes such as bacteria and viruses become able to resist the effects of medicines that previously killed them.

So, common and life-threatening infections, like pneumonia and gonorrhoea, and post-operative infections are increasingly becoming untreatable, said the United Nations, which held a general assembly last year to address the problem.

According to reports, it has been about 30 years since a new class of antibiotics hit the market.

The director-general of the World Health Organisation, Dr Margaret Chan, has also reportedly said that only two new classes of antibiotics had reached the market in the past 50 years.

But not all is gloomy on the horizon. In the mid-2000s, hospitals here began looking closely at a type of superbug called Methicillin-resistant Staphylococcus aureus (MRSA).

The bacteria would live in the nose of patients but only one in five to one in 10 of them would end up with infections, said Dr Hsu Li Yang, an associate professor and programme leader of the antimicrobial resistance programme at the Saw Swee Hock School of Public Health in the National University of Singapore.

The Republic is developing a national action plan to tackle the problem of resistant bacteria, which could include educating the public on which illnesses should be treated with antibiotics, and stepping up the monitoring of their use.

In hospitals, efforts include improving hand hygiene, checking patients to see if they carry the bug and isolating them from other patients if needed.

"A lot of work has been done on MRSA in Singapore in the last five to 10 years and figures are improving in most of Singapore's hospitals," said Professor Dale Fisher, head and senior consultant, Division of Infectious Diseases, at National University Hospital (NUH).

He added that, at NUH, most patients will be swabbed on admission so that necessary precautions can be taken to prevent the spread of superbugs.

The Ministry of Health said it has been working closely with hospitals to reduce the spread of antimicrobial resistance.

The number of MRSA bacteria infections found in patients' blood per 10,000 patient days fell from 0.89 in 2011 to 0.7 in 2015.

While these rates have dipped, experts voiced caution against the careless use of medicines.

A comprehensive approach is also needed to tackle the problem, said infectious diseases specialist Dr Paul Tambyah.

This includes public education, ensuring that people are not exposed to antibiotic resistant bacteria from imported food, good basic hygiene to prevent infections in the first place as well as discovering newer and better antibiotics.

Noted Prof Hsu: "Antimicrobial resistance is extremely difficult to reverse, if this is in fact even possible. Unlike the virus that causes severe acute respiratory syndrome (Sars),for example, antibiotic resistant bacteria are not going to 'disappear back into the wild'.

"They are part of the evolutionary process and are here to stay."

A version of this article appeared in the print edition of The Straits Times on January 06, 2017, with the headline 'Antibiotics no longer deliver KO punch'. Print Edition | Subscribe