Hospital-acquired listeriosis linked to a persistently contaminated milkshake machine.

One case of hospital-acquired listeriosis was linked to milkshakes produced in a commercial-grade shake freezer machine. This machine was found to be contaminated with a strain of Listeria monocytogenes epidemiologically and molecularly linked to a contaminated pasteurized, dairy-based ice cream product at the same hospital a year earlier, despite repeated cleaning and sanitizing. Healthcare facilities should be aware of the potential for prolonged Listeria contamination of food service equipment. In addition, healthcare providers should consider counselling persons who have an increased risk for Listeria infections regarding foods that have caused Listeria infections. The prevalence of persistent Listeria contamination of commercial-grade milkshake machines in healthcare facilities and the risk associated with serving dairy-based ice cream products to hospitalized patients at increased risk for invasive L. monocytogenes infections should be further evaluated.

Outbreak of Listeria monocytogenes infections linked to a pasteurized ice cream product served to hospitalized patients.

Two cases of hospital-acquired listeriosis were linked to a commercially produced, pasteurized ice cream mix. Manufacturers should implement safety measures from the Food Safety Modernization Act to minimize the risk of Listeria contamination. Dietary guidelines for persons at high risk of listeriosis may need revision to recognize the potential risk from pasteurized products.

Analysis of risk factors for tuberculous infection following exposure at a homeless shelter.

SETTING: A homeless shelter for men aged ⩾ 50 years in Seattle, Washington, USA. OBJECTIVES: We examined risk factors for tuberculous infection following exposure to an active pulmonary tuberculosis (TB) case residing in a homeless shelter setting. METHODS: A contact investigation identified shelter clients exposed to the index case; these contacts were then assessed for tuberculous infection. Risk factors, including proximity and duration of exposure to the index case, were evaluated for association with infection. A retrospective cohort study was conducted and a multivariate logistic regression model determined the magnitude of the association between tuberculous infection and significant risk factors. RESULTS: Of the 64 contacts evaluated, 25 (39%) had latent tuberculous infection and one had active TB. The multivariate logistic regression model found that duration of exposure and birthplace were significantly associated with odds of infection. CONCLUSIONS: Birthplace and duration of exposure were significant risk factors for tuberculous infection, underscoring the importance of this information when prioritizing contact investigations after TB exposure in congregate settings. We recommend that public health agencies work with homeless shelters to ensure that clients' attendance records contain the necessary information to facilitate contact tracing during public health TB investigations.

Sharing of drug preparation equipment as a risk factor for hepatitis C.

OBJECTIVES: This study investigated the sharing of drug preparation equipment as a possible route of hepatitis C virus (HCV) transmission. METHODS: HCV seroconversion was measured in a cohort of 317 injection drug users who tested negative for HCV antibody at recruitment. RESULTS: Cumulative HCV incidence was 16.7% per year. Among those who did not share syringes, HCV seroconversion was associated with sharing drug cookers and filtration cotton (adjusted risk ratio = 5.9; 95% confidence interval = 1.1, 31.7); 54% of HCV infections in injection drug users who did not share syringes were attributable to cooker/cotton sharing. CONCLUSIONS: Among injection drug users who do not share syringes, an important proportion of HCV infections may be attributed to cooker/cotton sharing.

Sulfa or sulfone prophylaxis and geographic region predict mutations in the Pneumocystis carinii dihydropteroate synthase gene.

To determine factors associated with mutations in the Pneumocystis carinii dihydropteroate synthase (DHPS) gene, a prospective study of human immunodeficiency virus (HIV)-infected patients with confirmed P. carinii pneumonia was conducted in Atlanta, Seattle, and San Francisco. Clinical information was obtained from patient interview and chart abstraction. DHPS genotype was determined from DNA sequencing. Overall, 76 (68.5%) of 111 patients had a mutant DHPS genotype, including 22 (81.5%) of 27 patients from San Francisco. In multivariate analysis, sulfa or sulfone prophylaxis and study site were independent predictors of a mutant genotype. Fourteen (53.8%) of 26 patients who were newly diagnosed with HIV infection and had never taken prophylaxis had a mutant genotype. The significance of geographic location as a risk factor for mutant genotype and the high proportion of mutant genotypes among persons never prescribed prophylaxis, including those newly diagnosed with HIV infection, provide indirect evidence that these mutations are transmitted from person to person either directly or through a common environmental source.

Genetic variation in Pneumocystis carinii isolates from different geographic regions: implications for transmission.

To study transmission patterns of Pneumocystis carinii pneumonia (PCP) in persons with AIDS, we evaluated P. carinii isolates from patients in five U.S. cities for variation at two independent genetic loci, the mitochondrial large subunit rRNA and dihydropteroate synthase. Fourteen unique multilocus genotypes were observed in 191 isolates that were examined at both loci. Mixed infections, accounting for 17.8% of cases, were associated with primary PCP. Genotype frequency distribution patterns varied by patients' place of diagnosis but not by place of birth. Genetic variation at the two loci suggests three probable characteristics of transmission: that most cases of PCP do not result from infections acquired early in life, that infections are actively acquired from a relatively common source (humans or the environment), and that humans, while not necessarily involved in direct infection of other humans, are nevertheless important in the transmission cycle of P. carinii f. sp. hominis.

Four-month, four-drug preventive therapy for inactive pulmonary tuberculosis.

Standard preventive therapy for inactive pulmonary tuberculosis (TB) is 12 mo of isoniazid. Shorter multiple-drug preventive regimens have been proposed. From December 1993 through January 1996 we evaluated a 4-mo, four-drug regimen of preventive therapy for patients with inactive TB, mostly newly arriving immigrants from countries with high rates of TB and of isoniazid resistance. Fifty-three evaluable patients received a 4-mo regimen of isoniazid, rifampin, ethambutol, and pyrazinamide. We compared their completion rate, side effects, and cost of treatment with those of 108 age-matched patients who had received 12 mo of isoniazid at an earlier time. Sixty-eight percent of patients on the 4-mo regimen completed treatment; 69% of those on the 12-mo regimen completed treatment (p = 0.9393). Side effects were more frequent for the 4-mo regimen (30.2%) compared with 12 mo of isoniazid (11.1%) (p = 0. 0027). The cost of providing an uncomplicated, self-supervised regimen was estimated to be almost four times greater for the four-drug regimen compared with isoniazid. These results show that, in terms of compliance, a four-drug, 4-mo regimen had no advantage over standard preventive therapy for persons with inactive pulmonary TB. On the other hand, the shorter, more intensive regimen was associated with more frequent adverse effects and was more costly.

A case-control study of necrotizing fasciitis during primary varicella.

OBJECTIVE: An increase in the incidence of necrotizing fasciitis (NF) occurring in previously healthy children with primary varicella was noted in the Washington State area between December 1993 and June 1995. Our objective was to investigate ibuprofen use and other risk factors for NF in the setting of primary varicella. METHODS: Case-control study. Demographic information, clinical parameters, and potential risk factors for NF were compared for cases and controls. Cases of NF were analyzed to identify potential determinants of NF complicated by renal insufficiency and/or streptococcal toxic shock syndrome. Multivariate logistic regression was used to evaluate the association between ibuprofen use and NF. A case was defined as a child with NF hospitalized within 3 weeks of primary varicella (n = 19). Controls were children hospitalized with a soft tissue infection other than NF within 3 weeks of primary varicella (n = 29). Odds ratios (ORs) of ibuprofen, as well as other potential risk factors were evaluated. In addition, demographic and clinical data as well as other potential risk factors were compared between cases and controls. RESULTS: After controlling for gender, age, and group A streptococcus isolation, cases were more likely than controls to have used ibuprofen before hospitalization (OR, 11. 5; 95% confidence interval, 1.4 to 96.9). In most children, ibuprofen was initiated after the onset of symptoms of secondary infection. Children with NF complicated by renal insufficiency and/or streptococcal toxic shock syndrome were more likely than children with uncomplicated NF to have used ibuprofen (OR, 16.0; 95% confidence interval, 1.0 to 825.0). Children with complicated NF also had a higher mean maximum temperature (40.9 degrees C vs 39.3 degrees C), and a longer mean duration of secondary symptoms (1.7 days vs 0.6 days) before admission than children with uncomplicated NF. CONCLUSION: Ibuprofen use was associated with NF in the setting of primary varicella. Additional studies are needed to establish whether ibuprofen use has a causal role in the development of NF and its complications during varicella.

Prevalence of antimicrobial drug-resistant Streptococcus pneumoniae in Washington State.

We conducted a survey to assess the prevalence and geographic distribution of antimicrobial drug resistance among invasive isolates of Streptococcus pneumoniae in Washington State. Sequential sterile-site pneumococcal isolates were submitted from 13 hospital laboratories between 1 October 1995 and 30 January 1997. We serotyped 275 isolates from adults and children and determined minimum inhibitory concentrations (MIC) for commonly used antimicrobial drugs. Data were abstracted from medical records to compare differences in outcome and risk factors for infection. Of the 275 isolates, 73 (26.5%) were nonsusceptible to one or more antimicrobial drugs. Penicillin-nonsusceptible pneumococci (PNSP, MIC > or = 0.1 microgram/ml) accounted for 42 (15.3%) of the 275 isolates including 4 (1.5%) resistant strains (MIC > or = 2 micrograms/ml). The 42 PNSP included serogroups 6, 9, 14, 19, and 23, all of which are represented in the 23-valent pneumococcal vaccine. PNSP were also nonsusceptible to trimethoprim/sulfamethoxazole (92.9%), erythromycin (38.1%), imipenem (28.6%), and ceftriaxone (23.8%). Forty-seven (17.1%) of the 275 isolates were multiple drug-nonsusceptible pneumococci (MDNSP). A significantly greater number of patients < or = 12 years of age were infected with MDNSP compared with those > 12 years. Prior use of antimicrobial drugs and an immunosuppressive disorder were risk factors for infection with PNSP. In summary, pneumococci nonsusceptible to penicillin and other antimicrobial drugs are prevalent among adults with invasive pneumococcal disease in Washington State. A large proportion of PNSP are resistant to other commonly used antimicrobial drugs. Local antibiotic susceptibility data should be considered when designing empiric treatment regimens.

Comparison of sensitivities to two commercially available tuberculin skin test reagents in persons with recent tuberculosis.

Discrepancies have been reported between results obtained with tuberculin skin tests (TSTs) performed with use of different reagents. We compared TST results and determined the sensitivities of the two commercially available TSTs in 51 human immunodeficiency virus-negative persons with culture-confirmed active tuberculosis. Simultaneous TSTs were done with use of the Mantoux method and 5-tuberculin unit purified protein derivative (PPD) tuberculin preparations from single lots of Aplisol and Tubersol. Aplisol skin test reactions ranged from 5 mm to 26 mm (median, 16.0 mm), and Tubersol reactions ranged from 7 mm to 23 mm (median, 15.0 mm). The mean difference in paired reaction sizes for the two reagents was 0.58 mm and was not statistically different from zero (P value, 0.26). The difference in reaction sizes was < or =2 mm in 55% and > or =5 mm in 18% of patients. With a cutoff of either 5 mm or 10 mm to define a positive reaction, all results were concordant, with sensitivity of 100% and 96%, respectively. We found indistinguishable reaction size distributions and median TST results for the two commercially available PPD TST reagents, Aplisol and Tubersol, in a population with recent culture-proven tuberculosis.

The epidemiology of HIV and AIDS in the United States.

The HIV/AIDS epidemic has slowed in growth and is approaching a leveling in incidence. However, the number of HIV-infected persons is high, and new infections continue to occur. The prevention of AIDS-related OIs and decreases in AIDS-related mortality are an encouraging sign that HIV-infected persons are living better and longer lives. However, if the improvements in clinical management and patient survival are not matched by reductions in HIV incidence, the population of HIV-infected persons will increase. The characteristics of persons with HIV infection are changing over time and must be monitored to properly target prevention and care. HIV/AIDS rates are highest for black and Hispanic Americans, and one fifth of persons with AIDS are women. Because of the decreases in HIV incidence and in prevalence for homosexual and bisexual men, an increasing proportion of infections in the United States are related to injecting drug use and heterosexual transmission. The characteristics of persons at risk for HIV infection differ regionally, and prevention efforts must be based on the characteristics of local HIV/AIDS trends. The reduction in the number of children with AIDS and HIV-infected transfusion recipients reflects the impact of an effective prevention intervention. The changes for homosexual and bisexual men and IDUs suggest a reduction in high-risk behaviors since the early years of the epidemic. Behavioral surveys indicate that heterosexual persons in the general population have adopted some protective behaviors, which may explain in part the HIV/AIDS surveillance trends. However, many young homosexual and bisexual men, IDUs, and other heterosexual persons continue to practice behaviors that lead to HIV infection. Further reduction in these risk behaviors and the adoption of protective behaviors among these populations will be necessary to further slow the spread of HIV infection and decrease the number of infected persons.

Clinical features that differentiate hantavirus pulmonary syndrome from three other acute respiratory illnesses.

To elucidate the early clinical characteristics of hantavirus pulmonary syndrome (HPS), we compared the clinical features of 24 cases of HPS with those of cases of bacteremic pneumococcal pneumonia (n = 30), influenza (n = 33), or unexplained adult respiratory distress syndrome (ARDS, n = 21). On admission, patients with HPS were less likely than outpatients with influenza to have reported sore throat (OR = 0.02, P < .01) and cough (OR = 0.1, P = .01) and were less likely than patients with pneumococcal pneumonia to have lobar infiltrates detected by chest roentgenography (OR = 0, P < .01). Multivariate discriminant analysis revealed that three clinical characteristics at admission (dizziness, nausea or vomiting, and absence of cough) and three initial laboratory abnormalities (low platelet count, low serum bicarbonate level, and elevated hematocrit level) served to identify all patients with HPS and to exclude HPS in at least 80% of patients with unexplained ARDS. These findings warrant further study and should facilitate the early recognition of patients with HPS, who may benefit from early critical-care intervention.

High prevalence of multidrug-resistant Streptococcus pneumoniae among children in a rural Kentucky community.

In 1992 drug-resistant Streptococcus pneumoniae was cultured with increasing frequency from aspirates of middle ear fluid from children with acute otitis media in a rural Kentucky community. To determine the prevalence of carriage of drug-resistant S. pneumoniae in the community, we obtained nasopharyngeal swabs from 158 (70%) of 227 children attending a child daycare center and from 82 children attending the county health center. S. pneumoniae was isolated from 126 children. Among 123 isolates tested 65 (53%) were penicillin-resistant, including 41 (33%) strains that were highly resistant; 61 (50%) were multidrug-resistant. Serotypes 19F, 6B, 23F and 6A comprised 89% of the penicillin-resistant isolates. Detection of a variety of serotypes and drug resistance patterns among nasopharyngeal isolates of S. pneumoniae suggests that multidrug-resistant pneumococcal strains are endemic in this community. Surveillance for drug-resistant pneumococci with the use of respiratory secretions obtained by nasopharyngeal swab may provide useful information on the prevalence of drug-resistant strains causing invasive disease and otitis media. Such information could be used to guide empiric therapy of pneumococcal infections.

Hantavirus pulmonary syndrome: a clinical description of 17 patients with a newly recognized disease. The Hantavirus Study Group.

BACKGROUND: In May 1993 an outbreak of severe respiratory illness occurred in the southwestern United States. A previously unknown hantavirus was identified as the cause. In Asia hantaviruses are associated with hemorrhagic fever and renal disease. They have not been known as a cause of human disease in North America. METHODS: We analyzed clinical, laboratory, and autopsy data on the first 17 persons with confirmed infection from this newly recognized strain of hantavirus. RESULTS: The mean age of the patients was 32.2 years (range, 13 to 64); 61 percent were women, 72 percent were Native American, 22 percent white, and 6 percent Hispanic. The most common prodromal symptoms were fever and myalgia (100 percent), cough or dyspnea (76 percent), gastrointestinal symptoms (76 percent), and headache (71 percent). The most common physical findings were tachypnea (100 percent), tachycardia (94 percent), and hypotension (50 percent). The laboratory findings included leukocytosis (median peak cell count, 26,000 per cubic millimeter), often with myeloid precursors, an increased hematocrit, thrombocytopenia (median lowest platelet count, 64,000 per cubic millimeter), prolonged prothrombin and partial-thromboplastin times, an elevated serum lactate dehydrogenase concentration, decreased serum protein concentrations, and proteinuria. Rapidly progressive acute pulmonary edema developed in 15 of the 17 patients (88 percent), and 13 patients, all of whom had profound hypotension, died (case fatality rate, 76 percent). Increases in the hematocrit and partial-thromboplastin time were predictive of death. CONCLUSIONS: Infection with a newly described hantavirus causes the hantavirus pulmonary syndrome, which is characterized by a brief prodromal illness followed by rapidly progressive, noncardiogenic pulmonary edema.

Radiographic resolution of community-acquired pneumonia.

Clinicians are frequently faced with patients in whom the radiographic resolution of community-acquired pneumonia seems delayed. Previous studies of radiographic resolution of the disease have yielded conflicting results. We prospectively assessed the radiographic resolution of pneumonia in 81 non-immuno-compromised patients, presenting to the emergency room and ambulatory clinics of a large university hospital, who met clinical and radiographic criteria for pneumonia. Serial chest radiographs were obtained every 2 wk for an initial period of 8 wk, and then every 4 wk until 24 wk had passed, or until all radiographic abnormalities had cleared. Forty-one of the 81 patients (50.6%) demonstrated complete clearance after 2 wk. Fifty of the 75 patients (66.7%) followed to 4 wk demonstrated complete clearance. The rate of clearance was inversely correlated with age (p < 0.001) and involvement of single versus multiple lobes (p < 0.0001) (log-rank test). Clearance was faster in those patients treated as outpatients (3.8 wk versus 9.1 wk, p = 0.03) and in patients who were nonsmokers (4.5 wk versus 8.4 wk, p = 0.05) (log-rank test). Multivariate regression analysis demonstrated that only age (relative risk for clearance, +0.79 per decade) and single versus multiple lobes involved (relative risk for clearance, 0.55 for more than one lobe) had independent predictive value (Cox proportional hazards regression model). The radiographic resolution of pneumonia occurs more rapidly in younger patients and in those with only a single lobe involved.(ABSTRACT TRUNCATED AT 250 WORDS)