Waterborne nosocomial infections

Waterborne pathogens cause infections in health-care facilities. Despite guidelines addressing these pathogens, outbreaks and pseudo-outbreaks continue to occur. We reviewed recent reports of infections caused by Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Chryseobacterium species, nontuberculous mycobacteria, and Legionella species. Mycobacterium avium complex (MAC) infection in HIV patients has been linked to hospital water distribution systems; molecular subtyping showed that MAC isolates in patients and hospital water were identical. In immunosuppressed patients, Fusarium infection has been linked to the hospital water distribution system; again molecular subtyping showed that isolates from patients and the water supply were identical. Parasites, especially Cryptosporidium, and viruses have also been implicated in nosocomial infection. Transmission occurs via contact, ingestion, aspiration, or aerosolization of potable water, or via the hands of health-care workers. Interventions designed to interrupt transmission of waterborne pathogens have included the use of antimicrobial handwashes, targeted disinfection of the water supply, and, in high-risk populations, restricting the use of tap water.     

Medical responsibility and nosocomial infections

Modifications of the civil and administrative jurisprudence regarding nosocomial infections reflect the will to pay the patient for compensation for injury. The June 29, 1999 decree of the French Court of Cessation shows the transition from presumption of malpractice to obligation of safety. The authors describe those modifications, including the physician's and hospital liabilities, and assess their consequences, as proof of an external cause is now mandatory while proof of absence of malpractice is no longer sufficient.     

The nosocomial infections and diabetes

The higher incidence of the nosocomial infections is induced of the advances in the diagnostic and therapeutic medicine. The nosocomial infections are divided in non-specific, specific, endogenous and exogenous infections. Diabetes comes under the risk factors of these infections. The rigid adherences to the epidemiological measures and regular control of them may lower the ocurence of the nosocomial infections.     

Secular trends in nosocomial infections: 1970–1979

Nosocomial infection data from a mean of 81 hospitals has been reported to the National Nosocomial Infections Study (NNIS) each year since 1970. Surveillance has been conducted by the hospitals on an average of 1.16 million patients annually. The median nosocomial infection rate is 341 per 10,000 patients discharged, ranging from 312 in 1970 to 358 in 1975. Since 1975 the rate has steadily declined to 329 in 1979. By category of hospital, infection rates for community-teaching and municipal hospitals have declined in recent years whereas those for community and university hospitals have not. Infection rates for patients on the surgical service have declined steadily since 1975 to the lowest levels reported, 457 per 10,000 surgical patients discharged in 1979, primarily due to a decrease in the rate of surgical wound infections. On obstetrics, infection rates have increased steadily since 1970, also primarily due to surgical wound infections. Bacteremias have increased in frequency, particularly those associated with infection at other sites. No major shifts have been noted in the relative frequency of the most common sites of infection or pathogens causing infections.     

Legionella spp.: community acquired and nosocomial infections

PURPOSE OF REVIEW: The key points of this review are the increasingly recognized risk of home-acquired Legionnaires' disease; the significance and potential pathogenic role of other species of Legionella spp., different from L. pneumophila, and of other microorganisms that are phylogenetically close to Legionella and that have been named as Legionella-like amoebal pathogens; the breakthrough in the diagnosis of the disease caused by new commercially available urine antigen detection tests; the controversy over sensitivity and specificity of serological diagnostic methods; the recognition of a variety of possible mixed infections, particularly in the immunocompromised population; and new and controversial aspects of the therapeutic approach to legionellosis. RECENT FINDINGS: During the last year a number of articles have provided clinically relevant insights into our knowledge of Legionnaires' disease. In view of the fact that Legionella spp. have progressively become recognized as relatively common causative agents of both community-acquired and nosocomial legionellosis, this is an opportune moment for this review. SUMMARY: If domestic aquatic reservoirs were eventually confirmed as significant agents of transmission of legionellosis, the adoption of preventive measures would then be crucial. The progressive identification of other species, different from L. pneumophila, as causative agents of pneumonia should both encourage microbiologists and clinicians to improve their diagnostic methodology and increase the awareness of these infections. Finally, the awareness of mixed infections, probably far more severe and perhaps not so uncommon as previously thought, has important clinical connotations for both the diagnostic and the therapeutic approach to legionellosis in the immunosuppressed host, particularly in those cases of delayed clinical resolution.     

Preventing nosocomial infections from gastrointestinal endoscopy

Gastrointestinal procedures have been associated with a wide range of infectious complications, including bacterial endocarditis. Although the rate of bacteremia from the patient's own flora is quite high after some procedures, only a few cases of endocarditis caused by gastrointestinal instrumentation have been reported. Because of the severity of the illness, however, antibiotic prophylaxis has been recommended for patients who are categorized as high risk for some procedures. Bacteremia and other infections, such as colitis, may also originate from a contaminated endoscope. To prevent such an occurrence, high-level disinfection has been recommended for gastrointestinal endoscopes. High-level disinfection includes manual cleaning of the endoscope, flushing of internal channels with a liquid chemical sterilant, and thorough rinsing and drying of internal lumens.     

Emerging issues in nosocomial fungal infections

Nosocomial fungal infections remain a serious cause of morbidity and mortality. As immunodeficient populations increase, the incidence of nosocomial fungal infections continues to rise. Although a wide variety of new and emerging fungi can cause nosocomial infections, Candida species remain the major etiologic agent. Candida species vary in their epidemiology and therapy. New diagnostic, epidemiologic, and therapeutic tools have been developed and are discussed in this review. They include the use of polymerase chain reaction-based diagnostic methods, recent advances in antifungal susceptibility testing, and comparative therapeutic and prophylactic trials. As advances in prevention, diagnosis, and therapy continue, nosocomial fungal infections and the morbidity and mortality associated with them can be reduced.     

Established and emerging waterborne nosocomial infections

PURPOSE OF REVIEW: To assess the recent advances in the field of waterborne nosocomial infections. RECENT FINDINGS: In the last year, many publications have confirmed the importance of well known nosocomial waterborne pathogens such as Legionella spp. or other Gram-negative bacteria, especially non-fermentative bacilli. There have also been numerous reports of outbreaks or pseudo-outbreaks caused by Mycobacteria spp. The most intriguing information relates to the possibility that some fungi causing nosocomial infections may originate from the hospital water distribution system. SUMMARY: Despite progress in understanding the pathogenesis of nosocomial waterborne infections, outbreaks, pseudo-outbreaks and sporadic infections still occur. Targeted quality control of hospital water, updated procedures for the appropriate use of sterile and non-sterile water, coupled with surveillance constitute the cornerstones of prevention of these infections.     

Survey of patients' knowledge of nosocomial infections

A survey of discharged patients revealed that 62% of respondents were aware of the risk of nosocomial infection before they received the survey. Of the respondents 12.4% said they had suffered from a nosocomial infection; 70% were concerned about their risk of acquiring a nosocomial infection in the future; 83% believed nosocomial infections were preventable; 69% said the risk of acquiring a nosocomial infection was never explained to them during hospitalization; and 62% were dissatisfied with the information that hospitals and the medical community provided concerning the risk of nosocomial infections. Fifty-seven percent were willing to pay an extra $7.14 mean per diem charge to enhance the hospital's infection control program if this payment would lower their risk of infection. This survey suggests that the subset of responding patients want to know more about the risk of nosocomial infections, and they are willing to pay for more resources to be channeled into effective infection control programs.     

Comparison of endemic and epidemic nosocomial infections

Epidemics account for a small proportion of preventable infections acquired in hospitals, but they have been important in defining sources, modes of spread, and methods for prevention and control of nosocomial infections. To characterize hospital-based epidemics, 265 consecutive outbreaks investigated by the Center for Disease Control between 1956 and 1979 were reviewed.Pseudoepidemics were found in 11 percent of the investigations, most often resulting from errors in processing microbiologic specimens or from surveillance artifacts. In 223 actual epidemics, the pathogens most commonly involved were Staphylococcus aureus (19 percent), tribe Klebsielleae (14 percent), Salmonella (13 percent), hepatitis B virus (8 percent), enteropathogenic Escherichia coli (5 percent), Pseudomonas (4 percent) and group A streptococci (4 percent). Sites of epidemic infection were closely linked to the responsible pathogens. Gastroenteritis (21 percent), skin infection (18 percent), bacteremia (12 percent), meningitis (11 percent) and hepatitis (10 percent), infrequent causes of endemic nosocomial infections, were frequently involved in epidemics. Over the 25-year period reviewed, staphylococcal epidemics and outbreaks of gastroenteritis due to Salmonella and Esch. coli declined in frequency and those due to gram-negative bacilli and hepatitis B virus increased. Since 1970, clusters of primary bacteremia were the most frequently investigated type of epidemic. Many epidemic strains of staphylococci obtained since 1975 or Enterobacteriaceae obtained since 1970 exhibited unusual drug resistance. Specific site-pathogen combinations were closely associated with characteristic reservoirs and modes of spread.     

Epidemiology and control of nosocomial viral infections

The impact of nosocomial viral disease, in terms of morbidity, mortality, and health care expenditures, should not be underestimated. Respiratory viruses, in particular, account for a substantial proportion of all nosocomial infections, especially among pediatric patients and the institutionalized elderly. The immunocompromised, very young, and chronically ill patients in hospitals are unusually vulnerable to serious viral illness. The emerging technology of rapid viral diagnosis will allow more timely and accurate recognition of viral infections, even in the smaller hospital with limited laboratory resources. Early recognition of viral diseases should, in turn, permit us to institute, and further evaluate, specific measures for their control. Appreciation of the epidemiology and transmission of these viruses will provide the framework for successful infection control strategies.     

Characteristics of gentamicin resistance in nosocomial infections

Characteristics of gentamicin resistance were studied in gram-negative bacilli from 50 consecutive patients with nosocomial infection, during a time when gentamicin resistance had recently become prevalent at Medical University Hospital. Burns, decubitus ulcers, and cystic fibrosis were common precipitating factors for acquisition of gentamicin-resistant organisms. Pseudomonas aeruginosa accounted for 76% and Enterobacteriaceae for 24% of isolates. There was high prevalence of cross-resistance to amikacin (61%) and tobramycin (58%). Of the P aeruginosa strains 36% possessed plasmids which were rapidly detected by agarose gel electrophoresis. None of the isolates transferred gentamicin resistance. Representative isolates failed to elaborate aminoglycoside-modifying enzymes or to take up labelled amikacin. Multiple immunotypes of P aeruginosa were identified. These data suggest that a nonplasmid mediated resistance mechanism such as impermeability was responsible for the emergence of gentamicin resistance.