EMERGING THREAT OF ANTIBIOTIC RESISTANCE

EMERGING THREAT OF ANTIBIOTIC RESISTANCE

By SOWNDHARYA. S

WHY ANTIBIOTICS? 

Antibiotics are medicines that fight infections caused by bacteria in humans and animals by either killing the bacteria or making it difficult for the bacteria to grow and multiply. Antibiotics ONLY treat certain infections caused by bacteria

THE RISE OF ANTIBIOTIC RESISTANCE:

          Since antibiotic regimens are often only used temporarily, they are much less lucrative than medications used to treat long-term illnesses. Furthermore, newly approved medications for the majority of other illnesses are quickly provided, while new antibiotics are often kept on hand and only used to treat infections that are resistant to more established medicines.

          The spread of resistance genes among bacterial populations is the other component promoting antibiotic resistance. There are numerous ways in which people have unintentionally sped up the evolution of bacterial resistance. One such unfavorable policy has historically been the over-prescription of antibiotics by physicians for symptoms that, in many circumstances, may not be brought on by bacteria. However, measures have been taken recently to reduce the use of antibiotics without a prescription. In surveys of medical visits from 1995 to 2005, the proportion of visits that ended in antibiotic prescriptions fell for all symptoms, including sinusitis, ear infections, colds, bronchitis, and sore throats. The use of combination medicines, switching between different classes of antibiotics often and avoiding the use of broad-spectrum and last-resort antibiotics whenever possible have also been used as measures to counteract the evolutionary pressure that hastens resistance. Antimicrobial stewardship programs are becoming more commonplace in hospital settings and have been correlated in many cases to significant reductions in some strains of resistant bacteria.

          In some circumstances, excessively protracted or ineffective treatment regimens may place needless evolutionary pressure on bacteria. When a phenotypically sensitive majority of bacteria is eliminated, a minority resistant bacterial phenotype may find itself in a less competitive and hence more beneficial environment. This might result in acquired drug resistance. A lack of knowledge about antibiotics has also led to their overuse, which in turn resulted in antimicrobial resistance.

          In a 2009 survey conducted in Europe, 20% of people who had taken antibiotics within the previous year claimed to have done so for influenza, a viral illness. Only 36% of those polled correctly identified the fact that medicines do not kill viruses. This specific type of abuse is particularly prevalent in nations where antibiotics are available without a prescription.

          The use of antibiotics in animal feedstocks has also exacerbated the spread of antibiotic resistance. Their usage for prophylaxis, metaphylaxis, and growth promotion, which according to one estimate amounted to 25–50% of all antibiotic intake in the early 2000s, is particularly egregious. There is strong evidence that the use of fluoroquinolones in food animals has led to the emergence of fluoroquinolone-resistant Escherichia coli, salmonella, and Campylobacter.

HUMAN INDEPENDENT RESISTANCE:

          Although there is no doubt that humans have made a significant contribution to the evolution of bacterial resistance, resistance has also arisen in nature without human influence. Even bacteria whose DNA was kept isolated in permafrost for 30,000 years contained resistance components. According to calculations based on the genetic divergence of genes involved in the biosynthesis of antibiotics, some antibiotics may have originated hundreds of millions of years ago.

          Antibiotic use (and misuse) by humans has undoubtedly subjected bacteria to abnormal selective pressure, speeding up their evolutionary process to the disadvantage of all living things. Faster development of novel medicines and more judicious usage of antibiotics currently on the market are unquestionably required to solve this issue.

EMERGENT BACTERIAL THREATS :

BACTERIUM	GRAM STAIN	RESPIRATION	PROBLEMATIC RESISTANCE
Staphylococcus aureus	+	Facultative anaerobe	β-lactams, glycopeptides
Clostridium difficile	+	Obligate anaerobe	β-lactams, quinolones
Klebsiella pneumoniae	-	Facultative anaerobe	β-lactams, quinolones, aminoglycosides
Enterobacter	-	Facultative anaerobe	β-lactams, quinolones

 

 

 

ANTIBIOTICS OF 21^st CENTURY:

CLASS	CLINICALLY INTRODUCED SINCE 2000	IN PAHSE II OR III TRIALS
Beta lactams	Biapenem, ceftaroline , doripenem, ertapenem	Ceftobiprole, ceftolozane, razupenem
Aminoglycosides	None	Plazomicin
Macrolides	Telithromycin	Cethromycin, Solithromycin
Tetracyclines	Tigecycline	Eravacycline, Omadacycline
Rifamycin	Rifaximin	None
Glycopeptides	Telavancin	Dalbavancin, Oritavancin
Quinolones	Balafoxacin, gemifloxacin, pazufloxacin, prulifloxacin	Avarofloxacin, delafloxacin finafoxacin,
Oxazolidinones	Linezolid	AZD5847, radezolid, sutezolid, tedizolid.

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