Molecular analysis of a hospital cafeteria-associated salmonellosis outbreak using modified repetitive element PCR fingerprinting.

A hospital cafeteria-associated outbreak of gastroenteritis due to Salmonella enterica serotype Infantis was retrospectively evaluated using modified repetitive element PCR (rep-PCR) fingerprinting with the ERIC2 and BOXA1R primers and computer-assisted gel analysis and dendrogram construction. Rep-PCR yielded objective between-cycler, same-strain similarity values of from 92% (composite fingerprints) to 96% (ERIC2 fingerprints). The 70 Salmonella isolates (which included 19 serotype Infantis isolates from the hospital outbreak, 10 other serotype Infantis isolates, and 41 isolates representing 14 other serotypes) were resolved well to the serotype level with each of the three fingerprint types (ERIC2, BOXA1R, and composite). Rep-PCR typing uncovered several historical serotyping errors and provided presumptive serotype assignments for other isolates with incomplete or undetermined serotypes. Analysis of replicate fingerprints for each isolate, as generated on two different thermal cyclers, indicated that most of the seeming subserotype discrimination noted in single-cycler dendrograms actually represented assay variability, since it was not reproducible in combined-cycler dendrograms. Rep-PCR typing, which would have been able to identify the presence of the hospital-associated serotype Infantis outbreak after the second outbreak isolate, could be used as a simple surrogate for serotyping by clinical microbiology laboratories that are equipped for diagnostic PCR.

Pseudomembranous colitis after itraconazole therapy.

A 53-yr-old man was admitted with new onset of abdominal pain and nonbloody diarrhea 1 month after exposure to the antifungal agent itraconazole. Flexible sigmoidoscopy demonstrated the presence of pseudomembranes, and subsequent evaluation excluded other causes of diarrhea. Disruption of the resident fungal flora of the colon by itraconazole is proposed as the mechanism by which this patient developed pseudomembranous colitis. This association has not previously been reported.

Human immunodeficiency virus type 1 and mucosal humoral defense.

Mucosal sites serve as the principle venues through which primary human immunodeficiency virus type 1 (HIV-1) infections are transferred from donor to host. These moist tissues, which provide the interface with the external environment, also provide access to many of the secondary opportunistic infections that aggravate and may accelerate HIV-1 disease. Antibodies to HIV-1, particularly of the IgG rather than the IgA class, have been detected in virtually all mucosal fluids from HIV-1-infected patients. However, the ability of such patients to generate de novo humoral responses to new mucosal pathogens is impaired. Current studies are directed to characterizing the functional role of natural and infection-derived antibodies in control of HIV-1 infection as well as the impact of HIV-1 disease on mucosal B cell responses to immunization and infection.

HIV and occupational risk. Evolving ways to protect healthcare workers.

HIV has significantly altered the face of healthcare and the lives of virtually everyone in our communities. The risk of transmission, particularly through needlestick injuries, continues to be a major concern for all of us working in healthcare services. Dr Thurn reviews new information about modes of HIV transmission, ways to reduce risks, and guidelines for managing exposures, should they occur.

Bacterial colonization of nursing home residents on admission to an acute care hospital.

Very little data obtained in a prospective, controlled fashion examines the prevalence of colonization with antibiotic-resistant bacteria and yeast in nursing home residents on admission to acute-care hospitals. We cultured swabs taken from all nursing home patients admitted to a medical center on selected days of the week. Age-matched control patients were also enrolled. Nasal, pharyngeal, and rectal or perineal swabs were done within 24 h of admission. Susceptibility to gentamicin was used as a marker for antibiotic resistance. Most nursing home patients (45/56) were colonized with gentamicin-resistant isolates of coagulase-negative staphylococci; in the control group, 24 patients only carried these organisms (P = 0.0001 chi square). The only resistant Gram-negative bacteria were recovered from control patients (3/56 vs. 0/56 nursing home residents; P = 0.12, Fisher's exact test). Yeast were common colonizers of both nursing home residents and controls but were more frequently recovered from nursing home patients (P = 0.03, chi square). Although colonization by antibiotic-resistant staphylococci of nursing home residents on admission to an acute-care hospital was common, resistant Gram-negative bacilli were not found in this study. Additional investigations are needed to determine the risk of infection/ colonization with resistant organisms in this population.

Impact of Streptococcus pneumoniae bacteremia and human immunodeficiency virus type 1 on oral mucosal immunity.

To determine whether defects in mucosal immunity were associated with invasive disease caused by a mucosal pathogen, Streptococcus pneumoniae, levels of salivary immunoglobulins and nonspecific immune factors were compared in subjects with human immunodeficiency virus type 1 (HIV-1) infection and in HIV-1-seronegative subjects with and without pneumococcal bacteremia. The IgA2 subclass may be of particular importance because S. pneumoniae produces IgA1 protease, which cleaves IgA1 but not IgA2. Levels (37-56 micrograms/mL) and proportions (11%-17%) of IgA2 were similar among groups. Serotype-specific capsular salivary IgA was present in a minority of patients with acute bacteremia. Levels of lactoferrin were increased with bacteremia. Neither selective mucosal IgA2 deficiency nor impaired nonspecific upper respiratory mucosal responses were associated with invasive pneumococcal disease during HIV-1 infection; thus, other defects in mucosal cellular responses and systemic immunity may predispose HIV-1-infected patients to invasive pneumococcal disease.

HIV worldwide. What has happened? What has changed?

The human immunodeficiency virus (HIV) has resulted in a worldwide pandemic of infection. By 1991 more than 350,000 AIDS cases had been reported to the World Health Organization, but it is estimated that there are now more than 10 million people infected worldwide. HIV can rapidly spread in new populations: The pandemic is composed of multiple smaller epidemics. In the United States, it is estimated that over a million people are infected with HIV. Methods of estimating this number include extrapolation from the number of reported cases of AIDS, use of mathematical modeling and back-calculation, and seroprevalence surveys. Minorities continue to be overrepresented among those infected, and the prevalence of HIV in women is increasing. In serosurveys, it has been found that as HIV prevalence rates rise, the ratio of infected males to infected females approaches 1:1, suggesting an increased proportion of hetero-sexual transmission. HIV is now variably present but widespread across the United States. The epidemiology of HIV-related illnesses is also changing, as can be seen with current patterns of tuberculosis. HIV continues to be an increasingly complex and dangerous global burden.

Dynamics of coagulase-negative staphylococcal colonization in patients and employees in a surgical intensive care unit.

Because there is little information about the frequency of carriage of various species of coagulase-negative staphylococci (CNS) in hospital staff, we prospectively investigated nasal CNS in patients and personnel in a Surgical Intensive Care Unit (SICU). The majority of CNS from personnel were Staphylococcus epidermiditis. The CNS species from patients on admission were more diverse and included multiply antibiotic-resistant S. haemolyticus. Patients' CNS became more like CNS colonizing personnel after admission with respect to both antimicrobial susceptibility and speciation. Plasmid and antibiotic sensitivity profiles of S. epidermidis resistant to multiple antibiotics from five patients were identified as those from one employee, but there was no evidence that this was of clinical significance. A variety of factors influence nasal colonization by CNS in SICUs. The nasal CNS of patients change after admission and may become more resistant and less diverse. The factors influencing changes in the antibiotic susceptibility and the aetiology of CNS infection require further study.

Methicillin-resistant Staphylococcus aureus in Minnesota nursing homes.

OBJECTIVE: To assess the experience of Minnesota nursing homes with methicillin-resistant Staphylococcus aureus (MRSA) and the policies and procedures used for its control. DESIGN: A 12-question survey, with primarily categorical responses, was mailed to the Directors of Nursing of all Minnesota long-term-care facilities. A follow-up mailing was sent to non-responders 5 weeks later. The mailing included a cover letter, a description of the study and its purposes, and a stamped return envelope. Four weeks after the second mailing, all non-responding institutions were contacted by telephone and invited to participated by mail or by completing the survey by telephone. SETTING: All long-term-care facilities in Minnesota licensed for skilled and intermediate care. PARTICIPANTS: The survey was directed to the Directors of Nursing of the long-term-care facilities with the request that, if another individual was better able to complete it, the survey be forwarded to them. RESULTS: Completed responses were obtained from 88% (395/445) of all long-term-care facilities in Minnesota. Forty-eight institutions (12%) had residents colonized or infected with MRSA. Only four (8%) of these facilities stated that MRSA was a problem; however, 33 (69%) of facilities with MRSA had sought outside help or consultation from a variety of sources for its control. Few facilities (7%) had cultured residents specifically for MRSA. Policies regarding the admission of colonized or infected persons were reported by 14% and 21% of facilities, respectively, and over 40% of these policies stated that persons with MRSA would not be accepted. Policies regarding the care of MRSA-colonized or -infected persons were not uniform. Both metropolitan and non-metropolitan facilities had residents with MRSA. CONCLUSIONS: Our results suggest that MRSA in long-term-care facilities may be a widespread and underrecognized problem. There is a need to develop uniform policies for the control of MRSA in nursing homes. These policies should consider the sources and objectives of long-term-care facilities.

Septic shock. Evaluation of a life-threatening condition.

Septic shock is a difficult and complex condition that requires a thorough and thoughtful approach in all aspects of care. The most likely cause may become apparent by considering the clinical presentation of the patient and information from the history, physical examination, and appropriate laboratory tests. Appropriate antibiotic therapy should be initiated as soon as possible. Only an aggressive diagnostic and therapeutic approach can reduce the mortality and morbidity of this condition.

Influenza A pneumonitis in a patient infected with the human immunodeficiency virus (HIV).

Influenza A results in considerable morbidity, mortality and economic costs. Although immunoprophylaxis and chemoprophylaxis are targeted toward high-risk groups, persons with human immunodeficiency virus (HIV) infection have not been widely recognized as being at increased risk of influenza infection. We report a case of influenza A pneumonitis in a patient infected with HIV. The literature on influenza immunization of HIV-infected patients is reviewed and the implications for public health are discussed. Consideration should be given to influenza immunization and chemoprophylaxis in this enlarging population. Further investigation of the pathogenesis and epidemiology of influenza in HIV-infected patients is warranted.

Nursing home-acquired pneumonia.

Pulmonary infection acquired in nursing homes has not been extensively studied. Those data that have been published about the frequency and nature of nursing home-associated pneumonias are reviewed here. It remains unclear whether or not these institutionally-acquired pneumonias differ significantly from those that would occur in an age-matched control group with community-acquired infection. Viral pneumonias are recognized as significant causes of morbidity in the elderly.