Sticky bacteria are more resistant to antibiotics, leading to high patient mortality

Klebsiella pneumoniae is a bacterium
that can cause a variety of infections.
These bacteria are becoming increasingly resistant to treatment, leading to life-threatening diseases
.
To address the lack of research on recent strains, a collaboration between Kobe and Taipei conducted a comparative analysis
.
They took samples
of a strain that produces broad-spectrum lactamase (ESBL) from infected patients in Japan.
ESBL reduces the effectiveness
of the -lactam antibiotics commonly used to treat infections such as penicillin and cephalomycin.
In addition, some new strains have a high viscosity (HMV); They are thicker and stickier
than previous varieties.
By analyzing samples that produced the esbl strains, the researchers found that many HMV strains also carry a higher percentage of viral disease-causing genes, and traditional drugs are ineffective
against them.
These results have important clinical application value
for establishing appropriate and rapid HMV strain treatment methods in Japan.


The research was conducted by a 2nd Master's student including Tanimoto Hiroshi (Kobe University Graduate School of Health Sciences; Research supervisors: Associate Professor Shigemori Katsumi, Professor Orawa Kayo of Tokuwa University in Kobe, Japan, Assistant Professor
Shibin Fang of Taipei Medical University, Taiwan.


The findings were published in the Journal of Microbiology, Immunology and Infection (impact factor: 10.
273) on August 20, 2022
.


Essentials.

• The results of this study, conducted in Japan, showed that the High Viscosity (HMV)k.
  pneumonia strain had a higher virulence gene rate than previous strains and also showed higher drug resistance
  .
  

• The CTX-M-15 esbl-producing strain is the most prevalent
  .
  The ability to produce ESBL makes these bacteria resistant to multiple antibiotics
  .
  These findings suggest that the ESBL gene may be transmitted
  between plants via fii plasmids.
  

Pneumonia
is a bacterium that can cause a variety of infections, including urinary tract and respiratory tract infections
.
Among these bacteria, high viscosity (HMV) K
has been reported.
Pneumonia, they are stickier than previous strains and cause a higher
risk of severe illness and death.


Previously, antibiotics were effective
for most patients with HMV strains.
However, in recent years, the presence of HMV strains producing prospectrase-lactamase (ESBL) has been confirmed
.
ESBL is an enzyme that breaks down drugs, rendering them ineffective
.
This is a serious problem because it means that in addition to the risk of serious disease, drug K
has been used so far to be used to treat.
Pneumonia is no longer effective
against these new strains.


In addition, the gene that produces esbl can be widely spread to other bacteria
through plasmids (small DNA molecules).
As these bacteria become increasingly resistant, it is crucial to monitor their characteristics and changes
in different countries and over decades.
However, no detailed investigation
of HMV strains has been conducted in Japan.
To solve this problem, the current research team conducted a comparative analysis of ESBL-producing strains from Japanese patients; HMV strains and previous non-HMV strains
.
For each strain, they compared efficacy, resistance, virulence gene distribution, and plasmid type
.


Methods Between 2012 and 2018,
291 esbl strains produced K
.
Among the infected patients with pneumonia in Japan, the class team investigated the efficacy, resistance, virulence genes and plasmid types
of 107 strains (54 HMV strains and 53 non-HMV strains).


The results showed that most HMV strains carried virulence genes and carried at a higher rate than non-HMV strains (Figure 1), suggesting that HMV strains had more virulence factors
.
In addition, K.
pneumonia capsule serotype has an effect
on the viscosity of bacteria.
This study found that among HMV strains, K2 capsule serotype was the most common (40.
2%)
.
Previous investigations have also reported many strains of K2 HMV and are therefore considered highly likely K2 strains.
Pneumonia is highly viscous accompanied by high toxicity
.


To assess the effectiveness of the drug against these strains, the researchers used the β-lactam antibiotic cefepime (14.
8% vs.
43.
4%, p=0.
005) and piperacillin/tazobactam (70.
4% vs.
92.
5%, p=0.
001), a combination drug
consisting of a β-lactam antibiotic (piperacillin) and an ESBL inhibitor (tazobactam).
。 They confirmed that these drugs were less effective (susceptible) against HMV strains than non-HMV strains (Figure 2).

These results suggest that HMV strains acquire resistance more frequently than non-HMV strains
.
In other words, drugs are increasingly ineffective
against them.


Next, the team investigated the presence of genes associated with ESBL production, a major cause of
drug resistance.
They found that an ESBL-producing gene called CX-M-15 had the highest prevalence in HMV and non-HMV strains (75.
9% and 60.
4%, respectively), with the predominant plasmid type of the gene being FII (52.
1%)
.
Studies conducted in other countries have also reported many K's
.
Pneumonia and CTX-M-15 esbl produce gene, and current research shows an upward trend
in strains with this gene in Japan.


In summary, HMV strains have a high virulence gene rate and a high level of
drug resistance.
In addition, their findings also suggest that the most common esbl-producing gene type is CTX-M-15, and suggest that FII-type plasmids may spread CTX-M-15 widely to other strains
.


Further research
on HMVk.
Pneumonia infection requires prompt treatment because of the high risk of severe disease
.
In addition, improper medication is the main cause
of drug resistance in these bacteria.
To treat HMV strains, it is critical
to have an accurate understanding of drug resistance and quickly select the appropriate drug.


This study studies that current HMVk pneumonia carries higher virulence gene rates and less effective drugs targeting them than previous non-HMV strains
.
These findings are expected to make a significant contribution
to the appropriate and rapid treatment of HMV strains in Japanese hospitals.


Further research into the mechanisms by which HMV strains cause severe disease and drug resistance will help establish new treatments
.

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