Infection control Information and Courses from MediaLab, Inc.

Podschun R. Ullmann U.: Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors Clinical Microbiology Reviews. 11(4):589-603, 1998 Bacteria belonging to the genus Klebsiella frequently cause human nosocomial infections. In particular, the medically most important Klebsiella species, Klebsiella pneumoniae, accounts for a significant proportion of hospital-acquired urinary tract infections, pneumonia, septicemias, and soft tissue infections. The principal pathogenic reservoirs for transmission of Klebsiella are the gastrointestinal tract and the hands of hospital personnel. Because of their ability to spread rapidly in the hospital environment, these bacteria tend to cause nosocomial outbreaks. Hospital outbreaks of multidrug-resistant Klebsiella species, especially those in neonatal wards, are often caused by new types of strains, the so-called extended-spectrum-beta-lactamase (ESBL) producers The incidence of ESBL-producing strains among clinical Klebsiella isolates has been steadily increasing over the past years. The resulting limitations on the therapeutic options demand new measures for the management of Klebsiella hospital infections. While the different typing methods are useful epidemiological tools for infection control, recent findings about Klebsiella virulence factors have provided new insights into the pathogenic strategies of these bacteria. Klebsiella pathogenicity factors such as capsules or lipopolysaccharides are presently considered to be promising candidates for vaccination efforts that may serve as immunological infection control measures.

Francois P. Vaudaux P. Foster TJ. Lew DP.: Host-bacteria interactions in foreign body infections. Infection Control & Hospital Epidemiology. 17:514-20, 1996 Persistent staphylococcal infections are a major medical problem, especially when they occur on implanted materials or intravascular catheters. This review describes some of the recently discovered molecular mechanisms of Staphylococcus aureus attachment to host proteins coating biomedical implants. These interactions involve specific surface proteins, called bacterial adhesins, that recognize specific domains of host proteins deposited on indwelling devices, such as fibronectin, fibrinogen, or fibrin. Elucidation of molecular mechanisms of S. aureus adhesion to the different host proteins may lead to the development of specific inhibitors blocking attachment of S. aureus, which may decrease the risk of bacterial colonization of indwelling devices.

Handwashing is the single most important method of infection control and prevention available.Take care to wash your hands: As soon as gloves are removed. Before and after direct patient contact. After toileting . Before and after meals. Anytime hands are visibly soiled. After contact with face or mouth.

Human papilloma virus (HPV) is estimated to be the most common sexually transmitted infection in the United States. Digene's hybrid capture assay for HPV received approval by the Food and Drug Administration (FDA) in 2003. Only in recent years have other manufacturers, such as Third Wave Technologies, added this virus to their testing capabilities.Mycobacterium species represented another desirable target for molecular testing. Although some improvements in cultivation and staining techniques had been realized through the incorporation of broth media and fluorochrome staining, identification is still hampered by the growth rate of the organism. Gen-Probe first marketed probes that would allow identification of tuberculosis, M. avium-intracellulare, and M. gordonae in culture positive specimens. These probes greatly streamlined the workup of culture positive specimens.Of great interest to both clinicians and infection control practitioners, is the direct detection of Mycobacterium in clinical specimens. Gen-Probe received FDA approval for its AMPLIFIED MTDâ product for this specific application (in smear positive specimens) in 1995. This method employs isothermal transcription mediated amplification; the amplicons are detected using the same hybridization as the culture confirmation tests.

MRSA presents both clinical and infection control challenges. Because of the increasing incidence of MRSA strains, empiric treatment for serious staph infections is usually vancomycin in the hospital setting. Although PNA-FISH can identify Staphyloccocus aureus more rapidly, it cannot yet differentiate MRSA from methicillin-susceptible S. aureus (MSSA) strains. Early differentiation of MRSA from non-MRSA strains could allow for adjustment from broad spectrum antimicrobial therapy, and reduced risk of development of resistance. Hospital acquired infections have garnered increasing attention from many quarters; MRSA is one of several drug resistant organisms that are of concern. Many institutions have implemented active surveillance culture (ASC) protocols to identify carriers of MRSA, both upon admission, and throughout the hospital stay. Identified carriers are placed under precaution protocols, to minimize risk of transmission to other patients during the hospital stay. MRSA status is also an important consideration for those patients who are being discharged to another facility (long term care or rehabilitation centers). Identifying carriers sooner rather than later can reduce the risk of transmission by earlier implementation of precaution protocols and reduce delays in discharge (and length of hospital stay) in situations where carrier status is needed prior to discharge. PCR methodologies offer the prospect of providing screening results 24 to 40 hours sooner than culture methodologies, depending on the culture medium employed.

Many species in the genus Enterococcus possess intrinsic resistance to commonly used antibiotics. Intrinsic resistance represents naturally encoded chromosomal characteristics that are present in most Enterococci. These resistance mechanisms affect primarily the aminoglycosides and beta lactam antibiotics, and create therapeutic challenges for the treatment of serious infections such as endocarditis or septicemia. In addition to intrinsic resistance, Enterococci can acquire genetic determinants that confer resistance to other antibiotics. The emergence and increasing frequency of vancomycin-resistant Enterococci (VRE) has presented both therapeutic and infection control challenges.

Enterococci are largely commensal organisms that are opportunistic pathogens. Underlying disease, an immunocompromised state, age, lengthy hospital stays or long term care, invasive treatments, and/or prior antimicrobial therapy are factors that are associated with significant infections with these species. As noted previously, Enterococci are intrinsically resistant to many antibiotics. Intrinsic resistance affects not only beta lactams (including a broad range of cepahlosporins) and aminoglycosides, but also clindamycin and trimethoprim/sulfamethoxazole. The standard recommended therapy for systemic infections is a combination of either penicillin or vancomycin and an aminoglycoside (gentamicin or streptomycin). The goal of combination therapy is to achieve a synergistic bacteriocidal effect between the cell wall agent and the aminoglycoside.In recent decades, increasing resistance to other antibiotics through acquired resistance mechanisms has become a growing therapeutic and infection control problem. Of key concern are high level resistance (HLR) to aminoglycosides and increasing resistance to glycopeptides such as vancomycin.

In regards to glycopeptide resistance, there are six phenotypes, three of which are more commonly occurring. The VanA phenotype has an inducible high level resistance to vancomycin as well as teicoplanin (encoded by the VanA gene). The VanB phenotype (encoded by two vanB genes) has moderate to high resistance to vancomycin only. The VanC phenotype (encoded by two vanC genes) demonstrates a non-inducible low level resistance to vancomycin. Van A and Van B are the most clinically significant phenotypes and are usually seen among Enterococcus faecalis and E. faecium isolates. Van C is both intrinsic and characteristic in E. gallinarum and E. casseliflavus. Because they are intrinsic rather than acquired, they represent a different impact/significance for hospital epidemiology; definitive speciation can have significance for infection control purposes.At the present time, both ampicillin and vancomycin resistance occur more frequently with E. faecium isolates than with E. faecalis. Most vancomycin resistant E. faecium strains possess the vanA gene.

Handwashing is the single most important method of infection control and prevention available.It prevents many other community and hospital acquired infections.It is essential in the prevention of bloodborne pathogen transmission.

Standard Precautions means treating all body fluids and substances as if they were infectious. Since you can't tell which specimen may carry a bloodborne pathogen, use appropriate infection control measures during all patient contacts & when handling all specimens.

According to the CDC guidelines, patients with clinical illness consistent with uncomplicated influenza who reside in an area where influenza viruses are circulating may not require diagnostic influenza testing for clinical management. Most mild cases of H1N1 infection are self-limiting and do not require confirmation. However, if a patient is hospitalized due to the severity of the symptoms, or if the diagnosis of the patient will provide needed information to the physician to direct clinical care, infection control decisions, or management of close contacts, diagnostic influenza testing should be done. In any case, if a decision to use antiviral treatment is made, the treatment should commence as soon as possible, without waiting for the results of confirmatory diagnostic tests.

To control the spread of infection, any of these events must occur: Person-to-person transmission is prevented.Host response is effectively stimulated to prevent, control, or eliminate infection.Antimicrobial treatment is effective against M. tuberculosis.Therefore, an effective TB infection control program must include: Prompt detectionAirborne precautionsTreatment

Administrative controls reduce the risk of exposure to persons who might have TB disease.Environmental controls prevent the spread and reduce the concentration of infectious droplet nuclei in ambient air.Respiratory protection controls are for situations that pose a high risk of exposure. These controls further reduce risk of occupational exposure to infectious droplet nuclei.

Health care workers must be alert for signs and symptoms of TB to protect themselves from inadvertent exposure.Help protect yourself, coworkers, patients, and visitors by: Having current TB screening according to the risk classification of your setting Understanding the risks of TB in your work area Practicing good infection control at work and at home