Beta-lactamases (β-lactamases) are enzymes produced by bacteria that provide multi-resistance to beta-lactam antibiotics such as penicillins, cephalosporins, cephamycins, monobactams and carbapenems (ertapenem), although carbapenems are relatively resistant to beta-lactamase. Beta-lactamase provides antibiotic resistance by breaking the antibiotics' structure. These antibiotics all have a common element in their molecular structure: a four-atom ring known as a beta-lactam (β-lactam) ring. Through hydrolysis, the enzyme lactamase breaks the β-lactam ring open, deactivating the molecule's antibacterial properties.
Neutropenia is an abnormally low concentration of neutrophils in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria, bacterial fragments and immunoglobulin-bound viruses in the blood. People with neutropenia are more susceptible to bacterial infections and, without prompt medical attention, the condition may become life-threatening.
Infective endocarditis is an infection of the inner surface of the heart, usually the valves. Signs and symptoms may include fever, small areas of bleeding into the skin, heart murmur, feeling tired, and low red blood cell count. Complications may include backward blood flow in the heart, heart failure – the heart struggling to pump a sufficient amount of blood to meet the body's needs, abnormal electrical conduction in the heart, stroke, and kidney failure.
The cephalosporins are a class of β-lactam antibiotics originally derived from the fungus Acremonium, which was previously known as Cephalosporium.
Cyclic neutropenia (CyN) is a rare hematologic disorder and form of congenital neutropenia that tends to occur approximately every three weeks and lasting for few days at a time due to changing rates of neutrophil production by the bone marrow. It causes a temporary condition with a low absolute neutrophil count and because the neutrophils make up the majority of circulating white blood cells it places the body at severe risk of inflammation and infection. In comparison to severe congenital neutropenia, it responds well to treatment with granulocyte colony-stimulating factor (filgrastim), which increases the neutrophil count, shortens the cycle length, as well decreases the severity and frequency of infections.
Piperacillin is a broad-spectrum β-lactam antibiotic of the ureidopenicillin class. The chemical structure of piperacillin and other ureidopenicillins incorporates a polar side chain that enhances penetration into Gram-negative bacteria and reduces susceptibility to cleavage by Gram-negative beta lactamase enzymes. These properties confer activity against the important hospital pathogen Pseudomonas aeruginosa. Thus piperacillin is sometimes referred to as an "anti-pseudomonal penicillin".
Piperacillin/tazobactam, sold under the brand name Tazocin among others, is a combination medication containing the antibiotic piperacillin and the β-lactamase inhibitor tazobactam. The combination has activity against many Gram-positive and Gram-negative bacteria including Pseudomonas aeruginosa. It is used to treat pelvic inflammatory disease, intra-abdominal infection, pneumonia, cellulitis, and sepsis. It is given by injection into a vein.
Carbapenems are a class of very effective antibiotic agents most commonly used for treatment of severe bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. Similar to penicillins and cephalosporins, carbapenems are members of the beta-lactam antibiotics drug class, which kill bacteria by binding to penicillin-binding proteins, thus inhibiting bacterial cell wall synthesis. However, these agents individually exhibit a broader spectrum of activity compared to most cephalosporins and penicillins. Furthermore, carbapenems are typically unaffected by emerging antibiotic resistance, even to other beta-lactams.
Community-acquired pneumonia (CAP) refers to pneumonia contracted by a person outside of the healthcare system. In contrast, hospital-acquired pneumonia (HAP) is seen in patients who have recently visited a hospital or who live in long-term care facilities. CAP is common, affecting people of all ages, and its symptoms occur as a result of oxygen-absorbing areas of the lung (alveoli) filling with fluid. This inhibits lung function, causing dyspnea, fever, chest pains and cough.
Cefepime is a fourth-generation cephalosporin antibiotic. Cefepime has an extended spectrum of activity against Gram-positive and Gram-negative bacteria, with greater activity against both types of organism than third-generation agents. A 2007 meta-analysis suggested when data of trials were combined, mortality was increased in people treated with cefepime compared with other β-lactam antibiotics. In response, the U.S. Food and Drug Administration (FDA) performed their own meta-analysis which found no mortality difference.
Ventilator-associated pneumonia (VAP) is a type of lung infection that occurs in people who are on mechanical ventilation breathing machines in hospitals. As such, VAP typically affects critically ill persons that are in an intensive care unit (ICU) and have been on a mechanical ventilator for at least 48 hours. VAP is a major source of increased illness and death. Persons with VAP have increased lengths of ICU hospitalization and have up to a 20–30% death rate. The diagnosis of VAP varies among hospitals and providers but usually requires a new infiltrate on chest x-ray plus two or more other factors. These factors include temperatures of >38 °C or <36 °C, a white blood cell count of >12 × 109/ml, purulent secretions from the airways in the lung, and/or reduction in gas exchange.
Neutropenic enterocolitis, also known as typhlitis, is an inflammation of the cecum that may be associated with infection. It is particularly associated with neutropenia, a low level of neutrophil granulocytes in the blood.
Sweet syndrome (SS), or acute febrile neutrophilic dermatosis, is a skin disease characterized by the sudden onset of fever, an elevated white blood cell count, and tender, red, well-demarcated papules and plaques that show dense infiltrates by neutrophil granulocytes on histologic examination.
Fever of unknown origin (FUO) refers to a condition in which the patient has an elevated temperature (fever) but, despite investigations by one or more qualified physicians, no explanation is found.
Hospital-acquired pneumonia (HAP) or nosocomial pneumonia refers to any pneumonia contracted by a patient in a hospital at least 48–72 hours after being admitted. It is thus distinguished from community-acquired pneumonia. It is usually caused by a bacterial infection, rather than a virus.
Clostridial necrotizing enteritis (CNE) is a severe and potentially fatal type of food poisoning caused by a β-toxin of Clostridium perfringens, Type C. It occurs in some developing regions, particularly in New Guinea, where it is known as pig-bel. The disease was also documented in Germany following World War II, where it was called Darmbrand (literally "bowel fire," or bowel necrosis). The toxin is normally inactivated by certain proteolytic enzymes and by normal cooking, but when these protections are impeded by diverse factors, and high protein is consumed, the disease can emerge.
Infections caused by exposure to ionizing radiation can be extremely dangerous, and are of public and government concern. Numerous studies have demonstrated that the susceptibility of organisms to systemic infection increased following exposure to ionizing radiation. The risk of systemic infection is higher when the organism has a combined injury, such as a conventional blast, thermal burn, or radiation burn. There is a direct quantitative relationship between the magnitude of the neutropenia that develops after exposure to radiation and the increased risk of developing infection. Because no controlled studies of therapeutic intervention in humans are available, almost all of the current information is based on animal research.
Plazomicin, sold under the brand name Zemdri, is an aminoglycoside antibiotic used to treat complicated urinary tract infections. As of 2019 it is recommended only for those in whom alternatives are not an option. It is given by injection into a vein.
A granulocyte transfusion is a medical procedure in which granulocytes are infused into a person's blood. Granulocyte transfusions were historically used to prevent and treat infections in people with neutropenia, but the practice declined in popularity in the 1980s. Interest in the procedure increased in the 1990s due to the development of more effective methods for harvesting granulocytes and a growing population of people with severe neutropenia from chemotherapy. However, the treatment's efficacy remains poorly understood and its use is controversial.
