A 20-hospital, 3-year ICMR study of over 150,000
patients finds that carbapenem drug-resistant infections are
driving up both deaths and treatment costs
A large
multi-centre study of over 150,000 patients in India’s 20
tertiary-care hospitals has put a stark number on one of the
top ten global health threats today: Antimicrobial
Resistance (AMR). AMR happens when infections easier to
treat earlier become difficult (or impossible) to treat due
to disease-causing microbe (such as bacteria, virus, fungi,
parasite) becoming drug resistant.
The findings offer
one of the clearest multi-centre pictures yet of the
clinical and economic burden when common Gram-negative
bacteria become resistant to carbapenem
antibiotics.
And the message is blunt: AMR is not
simply making infections harder to treat. It is translating
into more deaths and substantially higher treatment
costs.
Researchers compared outcomes among patients
infected with four major Gram-negative pathogens –
Escherichia coli (E. coli), Klebsiella pneumoniae (K.
pneumoniae), Acinetobacter baumannii (A. baumannii) and
Pseudomonas aeruginosa (P. aeruginosa) – looking
specifically at infections that were drug-resistant or
susceptible to carbapenem antibiotics. Carbapenem
antibiotics are a powerful group of broad-spectrum
antibiotics, upon which clinicians have traditionally relied
on when infections caused by Gram-negative bacteria become
resistant to other drugs. Resistance to these medicines
therefore leaves doctors with fewer therapeutic
options.
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E. coli is a common cause of urinary and
bloodstream infections; K. pneumoniae can cause pneumonia,
urinary infections and sepsis; A. baumannii is particularly
associated with critically ill hospital patients; and P.
aeruginosa can cause severe infections in people with
prolonged hospital exposure or underlying illness.
The
study authored by Dr Kamini Walia, Dr Sonam Vijay, Dr Nitin
Bansal, et al, published in The
Lancet Regional Health – Southeast Asia (Volume 53,
October 2026), analysed data from 20
tertiary-care hospitals across India between April 2022 and
April 2025. Dr Kamini Walia serves as a senior scientist at
Indian Council of Medical Research (ICMR), heads its
Descriptive Research Division and leads ICMR on
Antimicrobial Resistance (AMR).
Each of the 20
participating hospitals was required to designate a minimum
of 150 inpatient beds for Antimicrobial Resistance (AMR)
surveillance activities, including at least 50 intensive
care unit (ICU) beds and 100 ward beds.
“All patients
were followed up until their final clinical outcome
(discharge from the hospital or death),” notes the
study.
“Carbapenem drug-resistant infections caused
substantially higher mortality and treatment costs than
susceptible infections. Mortality was particularly high in
bloodstream infections, reaching 46–51% for carbapenem
drug-resistant Acinetobacter, Pseudomonas and Klebsiella,”
posted Dr Kamini Walia on LinkedIn. “For India, the study
highlights the need to move beyond drug resistance
surveillance to integrated surveillance linking AMR with
patient outcomes, while strengthening infection prevention,
right and timely diagnostics, antimicrobial stewardship and
access to effective newer antibiotics.”
A nationwide
snapshot of a growing threat
The scale of the
surveillance effort is significant.
Researchers
examined records from 159,336 hospitalised patients in the
20 tertiary-care hospitals, representing more than 1.75
million patient-days of hospital care. “Patient-days”
measures the total number of days all admitted patients
spend in a hospital or healthcare facility over a specific
period.
Of these patients, 27,283 had infections
confirmed microbiologically, while 26,213 (16.4% of the
entire hospitalised population studied) had Gram-negative
bacterial infections.
Among those with Gram-negative
infections, more than six in ten were resistant to
carbapenem antibiotics, according to the study’s
analysis.
Mortality rose across all four
bacteria
For every major pathogen examined, patients
with carbapenem drug-resistant infections faced a higher
risk of death than those infected with carbapenem
susceptible strains.
The difference was particularly
striking for E. coli and P. aeruginosa. Patients with
carbapenem-resistant E. coli had a 41% higher relative risk
of death than those with susceptible infections. For P.
aeruginosa, the corresponding increase was 43%.
For K.
pneumoniae, the relative risk was 33% higher, while
carbapenem-resistant A. baumannii was associated with a 16%
higher relative risk.
Absolute mortality data
underline the severity
According to the study’s
reported results, mortality was 24.4% for
carbapenem-resistant E. coli compared with 17.3% for
susceptible infections. For K. pneumoniae, mortality was
31.2% versus 23.5%. A. baumannii had particularly high
mortality overall: 37.9% among resistant infections compared
with 32.8% among susceptible infections. For P. aeruginosa,
the corresponding figures were 28.9% and 20.2%.
It is
important to note that bloodstream infections can rapidly
progress to sepsis and multi-organ failure, leaving little
room for delays or ineffective treatment. The most alarming
data appeared in bloodstream infections caused by carbapenem
drug-resistant non-fermenting bacteria, principally A.
baumannii and P. aeruginosa. Mortality in these cases
reached 46% to 51%.
AMR also comes with a financial
penalty
The study did not stop at
mortality.
Researchers also examined length of
hospitalisation and antibiotic treatment costs.
Drug-resistant infections required more expensive therapy,
with antibiotic costs 1.1 to 2 times higher than those
associated with susceptible infections.
Once
first-line or commonly used antibiotics no longer work,
clinicians may need newer, more expensive drugs or
combinations of antibiotics. Patients may also require
longer hospital stays, intensive monitoring and more complex
(and may be more expensive) care.
For hospitals
already operating under pressure, those costs accumulate
quickly.
The study found, for example, that patients
with carbapenem-resistant E. coli had an average hospital
stay of about 23 days, compared with about 18 days among
patients with susceptible E. coli infections. However,
length of hospital stay was carbapenem-resistant A.
baumannii and P. aeruginosa was shorter, which could be
because of high mortality. “This paradox likely reflects the
early mortality in carbapenem-resistant A. baumannii and P.
aeruginosa infections, leading to reduced length of hospital
stay owing to poor survival,” notes the study.
In
other words, drug resistance can create a vicious cycle: the
infection becomes harder to treat, treatment becomes more
complicated, hospitalisation can become longer, and costs
rise while the patient’s risk of dying increases.
The
changing antibiotic arsenal
The researchers also
looked at how clinicians were treating drug-resistant
infections.
For carbapenem-resistant E. coli and K.
pneumoniae, ceftazidime–avibactam was used more commonly
than polymyxin B, reflecting the changing therapeutic
landscape for difficult-to-treat Gram-negative
infections.
But the availability of newer antibiotics
does not eliminate the underlying problem.
Every new
antibiotic introduced into clinical practice exists within
an evolutionary contest. Bacteria that survive exposure can
acquire or select for resistance mechanisms, potentially
eroding the usefulness of drugs that were once considered
reliable.
That makes antimicrobial stewardship – the
effort to ensure antimicrobials (like antibiotics,
antivirals, antifungals and anti-parasitics) are used only
when appropriate, and that, after right and timely
diagnosis, the right drug is given at the right dose and for
the right duration. This is not merely a prescribing
principle but becomes a central part of preserving the
effectiveness of the remaining treatment options.
Why
health surveillance is indispensable
Much of the
available evidence on AMR comes from laboratory
surveillance, which can show whether bacteria isolated from
patients are resistant to particular antibiotics. But
knowing that drug resistance exists is different from
knowing what it does to patients in real-life hospital
settings across a diverse country like India.
The new
study links microbiological drug resistance to outcomes such
as mortality, hospitalisation and treatment costs across a
large multi-centre population.
That distinction is
crucial in India, where researchers have pointed to
fragmented surveillance, incomplete laboratory and clinical
data and a lack of standardised estimates of mortality
associated with resistant infections.
Was infection
acquired in the healthcare facility?
The study found
that 85% of E. coli infections were healthcare-associated
infections (or hospital acquired), 91.6% of K. pneumoniae
infections were healthcare-associated, 95.1% of A. baumannii
infections were healthcare-associated, and 91.9% of P.
aeruginosa infections were healthcare associated. “Among
blood stream associated infections across all pathogens,
again majority (more than 85%) were classified as
healthcare-associated infections,” notes the
study.
Those findings point beyond antibiotic
prescribing alone.
“Microbiologically confirmed
infections were classified as community-acquired if the
culture was positive within 48 hours of hospitalisation and
there was no history of hospitalisation within the preceding
90 days. Infections not meeting these criteria were
classified as healthcare-associated infections,” study
authors explain.
Infection prevention as important as
new antibiotics
If drug-resistant infections are
concentrated in healthcare settings, then preventing them in
the first place becomes as important as finding better drugs
to treat them.
The researchers ultimately call for
stronger surveillance, better infection prevention and
control, improved access to effective therapies and stronger
antimicrobial stewardship.
The implications extend
from intensive-care units to hospital laboratories and
pharmacy departments.
Hand hygiene, environmental
cleaning, appropriate use of invasive devices used in
medical procedures, rapid identification of drug-resistant
organisms (right and timely diagnosis and
drug-susceptibility testing where possible), isolation or
cohorting where appropriate, and careful antibiotic
prescribing, all form part of the efforts to save us from
drug-resistant infections.
So does health
surveillance.
A hospital cannot effectively control a
drug-resistant organism it cannot detect or track.
Government of India’s prestigious Indian Council of Medical
Research (ICMR)’s AMR Surveillance Programme led by Dr
Kamini Walia has made pathbreaking contributions over the
years to identify patterns and measure whether AMR
interventions are working.
The new multi-year study
was itself funded through an ICMR task-force
project.
A warning, not a verdict
The findings
are powerful, but they should not be read as proof that drug
resistance alone caused every death.
Persons with
drug-resistant infections may differ from those with
susceptible infections in important ways, including
underlying disease, severity of illness, prior antibiotic
exposure and healthcare-associated risk factors. Those
differences can influence outcomes independently of drug
resistance itself.
The researchers’ comparison
nevertheless provides strong evidence of an association
between carbapenem drug resistance and worse outcomes across
multiple major pathogens.
And the consistency is
difficult to ignore.
The study authors observe: “Most
of the hospitals, included in the study have very high
standards of infection control and are accredited by
national and international quality control boards, but they
are tertiary care hospitals, which predominantly manage
referred and critically ill patients; therefore, the rates
observed should not be interpreted as indicators of hospital
performance. We suspect that hospitals with poor laboratory
support to facilitate timely identification and treatment
may have far worse patient outcomes compared to what is
documented in this study.”
For the health system, this
study is another reminder that preventing drug-resistance –
and preventing infections from spreading in the first place
– may ultimately be far less costly than trying to outrun
bacteria after drug-resistance has emerged.
“Finally,
improving access to newer effective antimicrobials, is
crucial to reduce mortality associated with drug resistant
infections in India,” recommend study authors.
ICMR
researcher Dr Sonam Vijay rightly shared on LinkedIn that
“Our findings among 1.5 lakh (150,000) hospitalised
patients, including 16.4% with Gram-negative bacterial
infections, highlight the need for timely diagnostics and
access to effective, affordable novel antimicrobials to
improve outcomes and reduce the economic burden of
carbapenem-resistant infections.”
Shobha Shukla,
Bobby Ramakant – CNS (Citizen News
Service)
(Shobha Shukla and Bobby Ramakant are
part of CNS Editorial team as well as on the board of Global
AMR Media Alliance – GAMA. Follow them on X:
@Shobha1Shukla, @BobbyRamakant) – Shared under Creative
Commons
(CC)
