The control of healthcare-associated infections (HAIs) depends on effective hygiene, infection prevention and control measures, pertinent diagnostics and relevant use of antibiotics. These infections are a major cause of concern, as they negatively affect the outcome of patients,may extend the length of hospital stays and can generate significantly increased healthcare costs.
- In Europe, for instance, HAIs affect 6% to 12% of hospitalized patients.(46)
- In the USA, they affected more than 700,000 patients in 2011,(47) resulting in thousands of premature deaths and an estimated $30 billion in healthcare costs.
There is sometimes a false impression that healthcare-associated infections are adequately controlled. However, with new kinds of bacterial resistance appearing such as vancomycin-resistant enterococci (VRE) and carbapenem-resistant Enterobacteriaceae (CRE), such infections are more than ever a public health threat. HAIs also tend to show higher resistance rates to antibiotics than community-acquired infections.(48)
The main drivers of these infections are the presence of indwelling catheters, intravascular devices and mechanical ventilation systems which are themselves valuable tools for managing and treating various medical conditions.(42) However, the presence or use of these medical devices may lead to unintended infections as part of their routine use. Healthcare-associated pathogens can infect the blood stream (10-14% of HAIs), the respiratory tract (13-30% of HAIs), the urinary tract (14-34% of HAIs), the gastrointestinal tract (20% of HAIs), or surgical site incisions (13-30% of HAIs).(47),(49),(50),(51)
In healthcare settings, bacteria such as Staphylococcus aureus, Klebsiella pneumoniae or Acinetobacter baumannii spread readily between patients, leading to healthcare-associated outbreaks. Such outbreaks tend to occur in intensive care units and neonatal care facilities, where they affect the most vulnerable individuals such as pre-term infants, patients with impaired immune systems, or individuals who are affected by other diseases (e.g. diabetes), or those receiving advanced medical care (complex surgery, organ transplantation, medical device implants, etc.). Spread of these bacteria between hospitals and even across country borders through the transfer of infected or colonized patients has repeatedly been documented.
A common antibiotic-resistant bacteria found in hospitals is methicillin-resistant Staphylococcus aureus (MRSA). Thirty years ago, MRSA accounted for only 2 percent of Staphylococcus infections. By 2005, it accounted for nearly 60 percent of Staphylococcus infections in some hospitals. More recently, it has also become a source of community-acquired infections. In 2002, doctors discovered the first S. aureus strain resistant to vancomycin, one of the most commonly used antibiotics for treating MRSA infections.(52) More recently, Enterococcus followed a similar trajectory by becoming the second cause of healthcare-associated infections, with increasing rates of resistance to several critically important classes of antibiotics, including ampicillin, vancomycin and the aminoglycosides.(53)
Bacteria are not the only drug-resistant causes of infections in hospitals. Since 2009, a yeast called Candida auris has emerged as a new multidrug-resistant threat in hospitals around the world. Yeasts are not killed by antibiotics, they require antifungal drugs. Some strains of Candida auris have now acquired resistance to most of those drugs and can cause serious invasive infections which can be fatal, especially in patients with suppressed immune systems. After emerging in Japan, and being associated with outbreaks in 10 other countries, an increasing number of cases of the “superfungus” are being observed in the US, and the CDC is calling for increased awareness and infection control measures.(84)
Some microorganisms are particularly difficult to eradicate, due to their persistence in the environment (air, water, environmental surfaces or medical devices) and their contagiousness. bioMérieux’s infection prevention and control as well as environmental health solutions help ensure air and water quality, as well as surface cleanliness, to prevent airborne disease transmission and limit cross-transmission of microbial organisms through water, surfaces and medical devices.
Environmental Infection Control solutions
Sampl’Air™ is a high-performance easy-to-use instrument for the regular monitoring of air. It offers various culture media for both unprotected and protected healthcare areas.
DNP1+ Thiosulfate rinsing solution, GVPC Agar and bioNexia® Legionella, among other solutions, contribute to microbial detection at critical points (e.g. hemodialysis water control, endoscope disinfection control or Legionella detection in institutional water and cooling systems).
The bacterium Klebsiella pneumoniae is a colonizer of the gut in humans and other animals. ESBL-producing Klebsiella pneumoniae are one of the most common multidrug-resistant bugs involved in nosocomial infections worldwide.
- In hospitalized patients, Klebsiella pneumoniae is a common cause of urinary or respiratory tract infections, including severe pneumonia.
- Klebsiella pneumoniae can cause bloodstream infections in neonates with high mortality rates.
Klebsiella pneumoniae is increasingly resistant to carbapenems and polymyxins.
The bacterium Acinetobacter baumannii is increasingly becoming resistant to multiple antibiotics and is very good at surviving in healthcare settings. Its ability to form “biofilms” - even on environmental surfaces - protects it from the effects of antimicrobial agents and biocides and makes it extremely difficult to control.
- Acinetobacter baumannii is found in intensive care units, where it can cause ventilator-associated pneumonia, endocarditis, meningitis, and infections of the skin, soft tissues - not to mention those originating from prosthetic devices.
Acinetobacter baumannii is increasingly resistant to carbapenems.
Focus on carbapenem resistance
In 2014, bioMérieux initiated a collaborative project with Professor Patrice Nordmann, Head of the Bacteriology-Virology-Parasitology Department at Bicêtre Hospital in France and Director of INSERM Unit 914: Emerging Resistance to Antibiotics. This joint undertaking resulted in the launch of the RAPIDEC® CARBA NP test in 2014. This rapid, easy-to-use and cost-effective colorimetric test confirms the presence of carbapenemase-producing bacteria. It is one component of a comprehensive range of solutions to identify carbapenem resistance by combining several techniques: bacterial culture, rapid and conventional antibiotic susceptibility testing, molecular biology and strain typing.
THE EASY WAY TO CONTROL CARBAPENEMASE-PRODUCERS
Patrice Nordmann, MD, PhD
Professor and Chair of Microbiology
Medical and Molecular Microbiology Unit
Department of Medicine, Faculty of Science
University of Fribourg, Switzerland
"Reduced sensitivity or resistance to carbapenems may be caused by a bacteria producing a carbapenemase-type enzyme (ß-lactamase hydrolysing carbapenems). However, the antibiotic susceptibility profile is not sufficient to confirm or rule out the production of this type of enzyme.
The RAPIDEC® CARBA NP test* rapidly detects carbapenemase activity in Gram-negative bacteria, such as Enterobacteriaceae, P. aeruginosa and in A. baumannii. The test is based on detection of hydrolysis of the ß-lactam ring of a carbapenem (imipenem). The hydrolysis produces an acid derivative, which changes the color of the pH indicator (phenol red solution). This colorimetric change is visible to the naked eye; no reading device is required. Absence of color change within 2 hours indicates absence of carbapenemase-producing activity.
The RAPIDEC® CARBA NP test provides identification of carbapenem resistance in less than 2 hours (compared with 24-48 hours previously). It can be performed directly on isolated colonies grown on recommended selective or non-selective agars.
The test is recommended for rapid identification of any carbapenemase activity of Enterobacteriaceae, and specifically the forms most commonly found worldwide today:
Klebsiella pneumoniae carbapenemase (KPC); New Delhi metallo-ß-lactamase (NDM); Verona integron-encoded metallo-ß-lactamase (VIM), imipenemase (IMP) and oxacillinase-48 (OXA-48). For example, KPC-producing bacteria can be identified in less than 30 minutes.
The test has excellent sensitivity and specificity and enables any laboratory to rapidly implement its own screening program for carbapenemase-producing bacteria. The test does not require any specific equipment or additional technology."
* The RAPIDEC® CARBA NP test has been developed in collaboration with Professor Patrice Nordmann and Doctor Laurent Poirel based on the original Carba NP test.