Nosocomial bloodstream infections among human immunodeficiency virus-infected patients: incidence and risk factors

Mortality predictive factors of people living with human immunodeficiency virus and bloodstream infection

INTRODUCTION

Portugal has one of the highest mortality rates for people living with HIV (PLWHIV) in Europe. After antiretroviral therapy introduction, HIV-associated mortality declined, included the one associated with bloodstream infection (BSI). However it is still high, and European data are scarce . Therefore, characterizing BSI and defining prognostic factors may improve our approach.

METHODS

This was a 10-year retrospective study of predictive factors for 30-day and 3-year mortality in PLWHIV with BSI in a tertiary infectious diseases ward.

RESULTS

Of 2134 PLWHIV admissions, 145 (6.8%) had a BSI, mostly respiratory and catheter-related bacteremia and globally community-acquired. Nosocomial infections occurred in 42 (36%) cases, mostly caused by Enterococcus spp, Staphylococcus aureus, and Candida spp. PLWHIV with a BSI had higher 30-day mortality (27%) compared to those without a BSI (14%). APACHE II score, corticotherapy, and current intravenous drug use (IDU) had a prognostic impact on 30-day mortality. Three-year survival was 54% in PLWHIV with a BSI; a CD4 <200 cells, vascular or chronic pulmonary disease, and lymphoma were prognostic factors.

CONCLUSIONS

Patients with a BSI were more likely to present advanced HIV disease, have more comorbidities, a longer length of stay, and higher 30-day mortality. IDU and severity of infection determined the short-term prognosis. Three-year mortality was primarily influenced by lower CD4 cell counts, hematological tumor, and cardiopulmonary comorbidities. Systemic corticotherapy may influence nosocomial BSI and short-term prognosis.

Epidemiology and Outcomes of Bloodstream Infections in HIV-Patients during a 13-Year Period

No data on antibiotic resistance in bloodstream infection (BSI) in people living with HIV (PLWH) exist. The objective of this study was to describe BSI epidemiology in PLWH focusing on multidrug resistant (MDR) organisms. A retrospective, single-center, observational study was conducted including all positive blood isolates in PLWH from 2004 to 2017. Univariable and multivariable GEE models using binomial distribution family were created to evaluate the association between MDR and mortality risk. In total, 263 episodes (299 isolates) from 164 patients were analyzed; 126 (48%) BSI were community-acquired, 137 (52%) hospital-acquired. At diagnosis, 34.7% of the patients had virological failure, median CD4 count was 207/μL. Thirty- and 90-day mortality rates were 24.2% and 32.4%, respectively. Thirty- and 90-day mortality rates for MDR isolates were 33.3% and 46.9%, respectively (p < 0.05). Enterobacteriaceae were the most prevalent microorganisms (29.8%), followed by Coagulase-negative staphylococci (21.4%), and S. aureus (12.7%). In BSI due to MDR organisms, carbapenem-resistant K. pneumoniae and methicillin-resistant S. aureus were associated with mortality after adjustment for age, although this correlation was not confirmed after further adjustment for CD4 < 200/μL. In conclusion, BSI in PLWH is still a major problem in the combination antiretroviral treatment era and it is related to a poor viro-immunological status, posing the question of whether it should be considered as an AIDS-defining event.

HIV-associated comorbidities as mediators of the association between people living with HIV and hospital-acquired infections

BACKGROUND

Hospital-acquired infections (HAIs) lead to poor health outcomes in hospitalized patients and may be disproportionately affecting the aging population of people living with HIV (PLWH). This study determined the association between HIV and HAIs, and analyzed the potential mediating effects of comorbidities.

METHODS

The Louisiana Hospital Inpatient Discharge Database for the years 2011-2015 was used. All patients with at least 1 HAI diagnosis within this source population were included as cases in the case-control study, and a 1:1 ratio of controls was randomly selected from the same hospitals.

RESULTS

Of the 1,852,769 eligible hospital discharges that occurred from 2011 through 2015, there were 7,422 patients with at least 1 HAI. Marginal logistic regressions of the case-control sample showed a strong association between HIV and central line-associated bloodstream infections (CLABSIs), but an inverse association between HIV and any HAI. However, the mediation analyses revealed that having at least 1 comorbidity mediates the association between HIV and CLABSIs.

DISCUSSION

The unexpected inverse association between HIV and HAI could be attributed to the sample size of the exposed group of patients, or it could be explained by the mechanisms of treatment for HIV patients.

CONCLUSIONS

This study found that people living with HIV are at an increased risk of developing a CLABSI, which is consistent with the published literature. The mediation analyses indicated that having at least 1 comorbidity mediated the association between HIV and CLABSI diagnosis.

Impact of human immunodeficiency virus infection on mortality of patients who acquired healthcare associated-infection in critical care unit

To evaluate 30-day mortality in human immunodeficiency virus (HIV) and non-HIV patients who acquired a healthcare-associated infection (HAI) while in an intensive care unit (ICU), and to describe the epidemiological and microbiological features of HAI in a population with HIV.This was a retrospective cohort study that evaluated patients who acquired HAI during their stay in an Infectious Diseases ICU from July 2013 to December 2017 at a teaching hospital in Brazil.Data were obtained from hospital infection control committee reports and medical records. Statistical analysis was performed using SPSS and a multivariate model was used to evaluate risk factors associated with 30-day mortality. Epidemiological, clinical, and microbiological characteristics of HAI in HIV and non-HIV patients and 30-day mortality were also evaluated.Among 1045 patients, 77 (25 HIV, 52 non-HIV) patients acquired 106 HAI (31 HIV, 75 non-HIV patients). HIV patients were younger (45 vs 58 years, P = .002) and had more respiratory distress than non-HIV patients (60.0% vs 34.6%, P = .035). A high 30-day mortality was observed and there was no difference between groups (HIV, 52.0% vs non-HIV, 54.9%; P = .812). Ventilator-associated pneumonia (VAP) was more frequent in the HIV group compared with the non-HIV group (45.2% vs 26.7%, P = .063), with a predominance of Gram-negative organisms. Gram-positive agents were the most frequent cause of catheter associated-bloodstream infections in HIV patients. Although there was a high frequency of HAI caused by multidrug-resistant organisms (MDRO), no difference was observed between the groups (HIV, 77.8% vs non-HIV, 64.3%; P = .214). Age was the only independent factor associated with 30-day mortality (odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1.01-1.1, P = .017), while diabetes mellitus (OR: 3.64, 95% CI: 0.84-15.8, P = .085) and the Sequential Organ-Failure Assessment (SOFA) score (OR: 1.16, 95% CI: 0.99-1.37, P = .071) had a tendency to be associated with death.HIV infection was not associated with a higher 30-day mortality in critical care patients with a HAI. Age was the only independent risk factor associated with death. VAP was more frequent in HIV patients, probably because of the higher frequency of respiratory conditions at admission, with a predominance of Gram-negative organisms.

Bloodstream infections in patients living with HIV in the modern cART era

Retrospective multicentre study aiming at analysing the etiology, characteristics and outcome of bloodstream infections (BSI) in people living with HIV (PLWHIV) in an era of modern antiretroviral therapy. Between 2008 and 2015, 79 PLWHIV had at least 1 BSI, for a total of 119 pathogens isolated. Patients were mainly male (72.1%), previous intravenous drug users (55.7%), co-infected with HCV or HBV (58.2%) and in CDC stage C (60.8%). Gram-positive (G+) pathogens caused 44.5% of BSI, followed by Gram-negative (G−), 40.3%, fungi, 10.9%, and mycobacteria, 4.2%. Candida spp. and coagulase-negative staphylococci were the most frequent pathogens found in nosocomial BSI (17% each), while E.coli was prevalent in community-acquired BSI (25%). At the last available follow-up, (mean 3.2 ± 2.7 years) the overall crude mortality was 40.5%. Factors associated with mortality in the final multivariate analysis were older age, (p = 0.02; HR 3.8, 95%CI 1.2–11.7) CDC stage C (p = 0.02; HR 3.3, 95%CI 1.2–9.1), malignancies, (p = 0.004; HR 3.2, 95%CI 1.4–7.0) and end stage liver disease (p = 0.006; HR 3.4, 95%CI 1.4–8.0). In conclusion, the study found high mortality following BSI in PLWHIV. Older age, neoplastic comorbidities, end stage liver disease and advanced HIV stage were the main factors correlated to mortality.

Diagnosis of Intra Vascular Catheter-Related Infection

The use of central vascular catheters (CVC) is associated with a substantial number of complications, amongst which infections predominate. A diagnosis of CVC-related infection usually requires catheter removal for culture. Semiquantitative (roll-plate method) and quantitative methods (flush, vortex, centrifugation or sonication methods) are the most reliable diagnostic methodologies requiring catheter removal, because of their greater specificity. The roll-plate method is the simplest and most commonly used technique. This method only samples the external surface of the catheter, and is particularly indicated for recently inserted catheters in which extraluminal colonisation is the primary mechanism of infection. Luminal culture techniques, such as the quantitative methods, may be more relevant for catheters that have been in place for a long period of time. However, in up to 85% of removed CVC the culture is negative, and other diagnostic techniques that do not require catheter removal have been proposed, including paired quantitative blood cultures, endoluminal brushing, and differential time to positivity (DTP) of paired blood cultures. DTP, that compares the time to positivity for qualitative cultures of blood samples simultaneously drawn from the CVC and a peripheral vein, appears to be the most reliable in the routine clinical practice since many hospitals use automatic devices for qualitative blood culture positivity detection. More recently catheter-sparing direct diagnostic methods, which include Gram stain and acridin-orange leucocyte cytospin (AOLC) test, appeared to be especially useful because of the rapidity of results and the ability to distinguish different microorganisms, allowing early targeted antimicrobial therapy.

Epidemiology and management of healthcare-associated bloodstream infections in non-neutropenic immunosuppressed patients: a review of the literature

Advancements in medicine have led to a considerable increase in the proportion of patients living with severe chronic diseases, malignancies, and HIV infections. Most of these conditions are associated with acquired immune-deficient states and treatment-related immunosuppression. Although infections as a result of neutropenia have long been recognized and strategies for management were developed, non-neutropenic immunosuppression has been overlooked. Recently, community-acquired infections in patients with frequent, significant exposure to healthcare settings and procedures have been classified as 'healthcare-associated infections' since they are more similar to hospital-acquired infections. Most of the non-neutropenic immunosuppressed patients have frequent contact with the healthcare system due to their chronic and severe diseases. In this review, we focus on the healthcare-associated bloodstream infections in the most common non-neutropenic immunosuppressive states and provide an update of the recent evidence for the management of these infections.

Bloodstream infections in HIV-infected patients

In the combined antiretroviral therapy era, HIV-infected patients remain a vulnerable population for the onset of bloodstream infections (BSI). Worldwide, nontyphoid salmonellae, Streptococcus pneumoniae, Escherichia coli, Staphylococcus aureus and coagulase negative staphylococci are the most important pathogens. Intravenous catheter associated infection, skin-soft tissue infection and endocarditis are associated with Gram-positive bacteremia. Among the Gram-negative, nontyphoidal Salmonella have been previously correlated to sepsis. Other causes of BSI in HIV-infected patients are mycobacteria and fungi. Mycobacteria constitute a major cause of BSI in limited resource countries. Fungal BSI are not frequent and among them Cryptococcus neoformans is the most common life-threatening infection. The degree of immunosuppression remains the key prognostic factor leading to the development of BSI.

Risk Factors and Temporal Trends of Hospital-Acquired Infections (HAIs) Among HIV Positive Patients in Urban New York City Hospitals: 2006 to 2014

BACKGROUND

HIV-infected patients may be at a greater risk of Hospital-Acquired Infections (HAIs) but risks factors for HAIs have not been well described in this population.

OBJECTIVE

The aim of this study was to examine the incidence, temporal trends and risk factors of HAIs among adult HIV positive patients.

METHODS

This was a retrospective cohort study carried out in an academic health system in New York City which included four hospitals over a 9-year period from 2006 to 2014. Simple and multiple logistic regression models were built to determine risk factors associated with site-specific HAIs such as Urinary Tract Infections (UTIs), Pneumonia (PNUs) and Bloodstream Infections (BSIs).

FINDINGS

There were 10,575 HIV positive discharges and 1,328 had HAIs: 697 UTIs, 555 BSIs and 192 PNUs. The incidence rate of HAIs decreased from 19.8 to 15.1 new infections per 1000 persondays between 2006 and 2014 (p value<0.001). In addition to the expected risk factors of urinary catheter use for UTI and central venous line use for BSI, symptomatic HIV and renal failure were significant risk factors for both UTIs (95% CI OR: (1.24, 2.27) and (1.46, 2.11) respectively) and BSIs (95% CIs OR: (2.28, 4.18) and (1.81, 2.71) respectively).

CONCLUSION

HIV-infected patients had similar risk factors for HAIs as HIV-uninfected patients. Further research is required to address how patients' CD4 counts and viral loads affect their susceptibility to HAIs.

Device-Associated Infection Rates for Non–Intensive Care Unit Patients

Background.

Reference data from intensive care units (ICUs) are not applicable to non-ICU patients because of the differences in device use rates, length of stay, and severity of underlying diseases among the patient populations. In contrast to the huge amount of data available for ICU patients, appropriate surveillance data for non-ICU patients have been missing in Germany.

Objective.

To establish a new module (“DEVICE-KISS”) of the German Nosocomial Infection Surveillance System for generating stratified reference data for non-ICU wards.

Setting.

Non-ICU patients from 42 German hospitals.

Methods.

Monthly patient-days, device-days and nosocomial infections (NIs) (using Centers for Disease Control and Prevention definitions) were counted. Device use rates were calculated, and NI rates were stratified by different medical specialities.

Results.

From July 2002 through June 2004, among the 77 wards, there were a total of 536,955 patient-days and 74,188 device-days (for CVC-associated primary bloodstream infections, there were 181,401 patient-days and 8,317 central vascular catheter [CVC]-days in 29 wards; for urinary catheter–associated urinary tract infections, there were 445,536 patient-days and 65,871 urinary catheter–days in 65 wards) and 483 NIs (36 bloodstream infections and 447 urinary tract infections). The mean device use rates were 4.6 device-days per 100 patient-days for CVCs (29 wards) and 14.8 device-days per 100 patient-days for urinary catheters (65 wards), respectively. Mean device-associated NI rates were 4.3 infections per 1,000 CVC-days for CVC-associated bloodstream infections and 6.8 infections per 1,000 urinary catheter–days for catheter-associated urinary tract infections.

Conclusions

DEVICE-KISS allows non-ICUs to recognize an outlier position with regard to NIs by providing well-founded reference data for non-ICU patients.

Risk of healthcare associated infections in HIV positive patients

HIV positive patients are a high risk population due to the alteration in their immune status. Health-care associated infections (HAI) have not been well described in this population, with some risk factors reported inconsistently in the literature. The aim of this study was to describe the epidemiology as well as the underlying risk factors for HAI, specifically urinary tract infection (UTI), bloodstream infection (BSI) and respiratory tract infection (RTI). This was a retrospective cohort study conducted at an academic health system in New York City which included three hospitals over a two year period from 2006 to 2008. There were 3,877 HIV positive patient discharges in 1,911 patients. There were a total of 142 UTI, 106 BSI, and 100 RTI. The incidence rates were 4.35 for UTI, 3.16 for BSI and 2.98 for RTI. CD4 count and antiretroviral therapy were not associated with HAI. Significant predictors of UTI included urinary catheter, length of stay, female gender, steroids and trimethoprim-sulphamethoxazole (TMP-SMX); of BSI were steroids and TMP-SMX; and RTI were mechanical ventilation, steroids and TMP-SMX. Multivariable analysis indicated that TMP-SMX was significantly associated with an increased risk of infection for all three types of HAI [BSI odds ratio 2.55, 95% confidence interval (1.22-5.34); UTI odds ratio 3.1, 95% confidence interval (1.41-7.22); RTI odds ratio 5.15, 95% confidence interval (1.70-15.62)]. HIV positive patients are at significant risk for developing HAI, but the risk factors differ depending on the specific type of infection. The fact that TMP-SMX is a risk factor in these patients warrants further research as this may have significant health policy implications.

Staphylococcus aureus infections in HIV-positive children and adolescents

A retrospective case-control study was undertaken among patients followed at the Texas Children's Hospital Retrovirology Clinic to determine the risk factors for Staphylococcus aureus infection. A total of 28 episodes of S. aureus infection were identified from 20 patients. Case patients had more advanced HIV disease as measured by CD4 T-cell counts, log10 human immunodeficiency viral load, and Centers for Disease Control and Prevention category of disease, than controls.

HIV infection and pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare but severe disease that results from chronic obstruction of small pulmonary arteries, leading to right ventricular failure and, ultimately, death. One established risk factor for the development of PAH is HIV infection. In comparison with the incidence of idiopathic PAH in the general population (1-2 per million), HIV-infected patients have a 2500-fold increased risk of developing PAH. The presence of PAH is an independent risk factor for mortality in patients with HIV infection, and in most cases death is causally related to PAH rather than to other complications of HIV infection. This article will focus on HIV-PAH with special considerations to epidemiology, pathogenesis, clinical presentation, diagnostic approach and available treatments.

Shooting up: the interface of microbial infections and drug abuse

Illicit drug control has been on the global agenda for more than a century. Infections have long been recognized as one of the most serious complications of drug abuse. Drug users are susceptible to pulmonary, endovascular, skin and soft tissue, bone and joint, and sexually transmitted infections caused by a wide range of bacterial, viral, fungal and protozoal pathogens. In addition, injection drug users are at increased risk for parenterally acquired infections such as human immunodeficiency virus, hepatitis B virus, hepatitis C virus, tetanus and malaria. Factors related to drug use, such as unsterile injection practices, contaminated drug paraphernalia and drug adulterants, increase the exposure to microbial pathogens. Illicit drugs also affect several components of the complex immune system and thus modulate host immunity. In addition, lifestyle practices such as multiple sexual partners, overcrowded housing arrangements and malnutrition serve as co-factors in increasing the risk of infection. In this review we present an overview of the unique aspects of microbial pathogenesis, immune modulation and common infections associated with drug use. We have restricted the definition of drug abuse to the use of illegal drugs (such as opiates, marijuana, cocaine, heroin and amphetamines), not including alcohol and nicotine.

Hospital epidemiology and infection control in acute-care settings

Health care-associated infections (HAIs) have become more common as medical care has grown more complex and patients have become more complicated. HAIs are associated with significant morbidity, mortality, and cost. Growing rates of HAIs alongside evidence suggesting that active surveillance and infection control practices can prevent HAIs led to the development of hospital epidemiology and infection control programs. The role for infection control programs has grown and continues to grow as rates of antimicrobial resistance rise and HAIs lead to increasing risks to patients and expanding health care costs. In this review, we summarize the history of the development of hospital epidemiology and infection control, common HAIs and the pathogens causing them, and the structure and role of a hospital epidemiology and infection control program.

[Guidelines for the diagnosis and treatment of patients with bacteriemia. Guidelines of the Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica]

Bacteremia is a complex clinical syndrome in constant transformation that is an important, growing cause of morbidity and mortality. Even though there is a great deal of specific information about bacteremia, few comprehensive reviews integrate this information with a practical AIM. The main objective of these Guidelines, which target hospital physicians, is to improve the clinical care provided to patients with bacteremia by integrating blood culture results with clinical data, and optimizing the use of diagnostic procedures and antimicrobial testing. The document is structured into sections that cover the epidemiology and etiology of bacteremia, stratified according to the various patient populations, and the diagnostic work-up, therapy, and follow-up of patients with bacteremia. Diagnostic and therapeutic decisions are presented as recommendations based on the grade of available scientific evidence.

The risk of bloodstream infection in adults with different intravascular devices: a systematic review of 200 published prospective studies

OBJECTIVE

To better understand the absolute and relative risks of bloodstream Infection (BSI) associated with the various types of intravascular devices (IVDs), we analyzed 200 published studies of adults In which every device in the study population was prospectively evaluated for evidence of associated infection and microbiologically based criteria were used to define IVD-related BSI.

METHODS

English-language reports of prospective studies of adults published between January 1, 1966, and July 1, 2005, were identified by MEDLINE search using the following general search strategy: bacteremla [Medical Subject Heading, MeSH] OR septicemia [MeSH] OR bloodstream Infection AND the specific type of intravascular device (e.g., central venous port). Mean rates of IVD-related BSI were calculated from pooled data for each type of device and expressed as BSIs per 100 IVDs (%) and per 1000 IVD days.

RESULTS

Point incidence rates of IVD-related BSI were lowest with peripheral Intravenous catheters (0.1%, 0.5 per 1000 IVD-days) and midline catheters (0.4%, 0.2 per 1000 catheter-days). Far higher rates were seen with short-term noncuffed and nonmedicated central venous catheters (CVCs) (4.4%, 2.7 per 1000 catheter-days). Arterial catheters used for hemodynamic monitoring (0.8%, 1.7 per 1000 catheter-days) and peripherally inserted central catheters used in hospitalized patients (2.4%, 2.1 per 1000 catheter-days) posed risks approaching those seen with short-term conventional CVCs used in the Intensive care unit. Surgically implanted long-term central venous devices--cuffed and tunneled catheters (22.5%, 1.6 per 1000 IVD-days) and central venous ports (3.6%, 0.1 per 1000 IVD-days)--appear to have high rates of Infection when risk Is expressed as BSIs per 100 IVDs but actually pose much lower risk when rates are expressed per 1000 IVD-days. The use of cuffed and tunneled dual lumen CVCs rather than noncuffed, nontunneled catheters for temporary hemodlalysis and novel preventive technologies, such as CVCs with anti-infective surfaces, was associated with considerably lower rates of catheter-related BSI.

CONCLUSIONS

Expressing risk of IVD-related BSI per 1000 IVD-days rather than BSIs per 100 IVDs allows for more meaningful estimates of risk. These data, based on prospective studies In which every IVD in the study cohort was analyzed for evidence of infection by microbiologically based criteria, show that all types of IVDs pose a risk of IVD-related BSI and can be used for benchmarking rates of infection caused by the various types of IVDs In use at the present time. Since almost all the national effort and progress to date to reduce the risk of IVD-related Infection have focused on short-term noncuffed CVCs used in Intensive care units, Infection control programs must now strive to consistently apply essential control measures and preventive technologies with all types of IVDs.

Bacteremias: a leading cause of death

Bloodstream infections (BSIs), recognized to be a major cause of morbidity and mortality globally, are increasing in incidence. The reported rates of crude and attributable mortality vary, possibly due to heterogeneity in patient populations and methodology. Few studies, however, have focused on pathogen-specific attributable mortality. These studies include S. aureus, coagulase-negative staphylococci and enterococcus. Other studies of attributable mortality have been conducted in select populations such as nosocomial and community-acquired cohorts, intensive care units, neutropenic patients, and HIV-positive patients. Regrettably, despite advances in treatment and intensive care facilities, mortality remains high.

Epidemiologische Grundlagen

Eine Vielzahl an Faktoren tragen zu erhöhten nosokomialen Infektionsraten bei. Die Lebenserwartung und damit der Anteil alter Patienten mit z. T. chronischen Krankheiten steigen stetig an. Medizinische Fortschritte in Diagnostik und Therapie führen zu einer höheren Anzahl der dafür erforderlichen Eingriffe. Es werden immer häufiger immunsupprimierte Patienten (Infektiologie, Rheumatologie, Hämatologie/Onkologie, Transplantation von Organen usw.) behandelt. Das zunehmende Problem der Antibiotikaresistenz von Erregern und die Konsequenzen nosokomialer Infektionen erfordern eine verlässliche Epidemiologie auf diesem Gebiet. Konsequenzen betreffen einerseits Patienten, bei denen es zu einer erhöhten Morbidität und Letalität durch nosokomiale Infektionen kommt, aber andererseits auch das Gesundheitswesen, dem zusätzliche — vermeidbare? — finanzielle Belastungen entstehen.

Evidenzbasierte Empfehlungen, bei denen der jeweilige Einzelfall und die örtlichen Besonderheiten ebenfalls Berücksichtigung finden, sind Voraussetzung für eine sinnvolle und kosteneffektive Vorgehensweise zur Senkung der nosokomialen Infektionsrate. In vielen Studien sind Häufigkeiten und Folgen verschiedener nosokomialer Infektionsarten sowie Maßnahmen zu ihrer Prävention untersucht worden. Um die Qualität solcher Studien und die darauf basierenden Empfehlungen von Experten, die ja oftmals ebenfalls mit Kosten verbunden sind, kritisch beurteilen zu können, ist epidemiologisches Wissen unverzichtbar. Dies beinhaltet selbstverständlich auch die Kenntnis der jeweiligen Erreger solcher Infektionen sowie das Wissen um erregerspezifische Übertragungswege. Die Epidemiologie nosokomialer Infektionen ist daher die Grundlage ihrer eigenen Verbesserung.

»Es gibt nicht Kranke und Gesunde, sondern es gibt nur Untersuchte und nicht Untersuchte« (Johannes Rau, ehemaliger Bundespräsident).

A molecular epidemiological analysis of 2 Staphylococcus aureus clonal types colonizing and infecting patients with AIDS

BACKGROUND

Persons with acquired immune deficiency syndrome (AIDS) who use drugs appear to be at increased risk for colonization and infection with Staphylococcus aureus. Little is known about the nature of and risk factors responsible for this association. This study is among the first to prospectively follow carriage and infection in this uniquely high-risk population.

METHODS

We prospectively followed the cases of 75 patients with AIDS in a residential drug treatment facility and screened for S. aureus nasal colonization and infection.

RESULTS

Thirty-seven baseline cultures (49%) were positive for S. aureus, and 81% of subjects were colonized at least once during the study. Thirteen subjects experienced 17 infections. Pulsed-field gel electrophoresis and sequence-based typing methods revealed that 244 (92%) of the isolates belonged to either clonal type A or B. Clonal type A was methicillin-susceptible. Clonal type B consisted of 3 main subtypes (B1, B2, and B3), all with the same allelic profile (ST8) and staphylococcal protein A gene (spa) type (7). Of note, subtype B1 was methicillin-susceptible (ST8 and spa type 7), lacking mecA, whereas the other B clones were methicillin-resistant. Both clones were resistant to trimethoprim-sulfamethoxazole. Clonal type B isolates were relatively resistant, suggesting prior exposure to the health care setting.

CONCLUSIONS

This study demonstrates a sustained high rate of S. aureus carriage and infection. It demonstrates the capacity of unique methicillin-resistant S. aureus clones with an established linkage to earlier outbreaks of methicillin-resistant S. aureus, as well as to human immunodeficiency virus--infected subjects, to persist in this residential setting. It also illustrates the apparent genetic instability or transmissibility of the staphylococcal chromosomal cassette mec type IV element.

Immunopathogenesis of oropharyngeal candidiasis in human immunodeficiency virus infection

Oropharyngeal and esophageal candidiases remain significant causes of morbidity in human immunodeficiency virus (HIV)-infected patients, despite the dramatic ability of antiretroviral therapy to reconstitute immunity. Notable advances have been achieved in understanding, at the molecular level, the relationships between the progression of HIV infection, the acquisition, maintenance, and clonality of oral candidal populations, and the emergence of antifungal resistance. However, the critical immunological defects which are responsible for the onset and maintenance of mucosal candidiasis in patients with HIV infection have not been elucidated. The devastating impact of HIV infection on mucosal Langerhans' cell and CD4(+) cell populations is most probably central to the pathogenesis of mucosal candidiasis in HIV-infected patients. However, these defects may be partly compensated by preserved host defense mechanisms (calprotectin, keratinocytes, CD8(+) T cells, and phagocytes) which, individually or together, may limit Candida albicans proliferation to the superficial mucosa. The availability of CD4C/HIV transgenic mice expressing HIV-1 in immune cells has provided the opportunity to devise a novel model of mucosal candidiasis that closely mimics the clinical and pathological features of candidal infection in human HIV infection. These transgenic mice allow, for the first time, a precise cause-and-effect analysis of the immunopathogenesis of mucosal candidiasis in HIV infection under controlled conditions in a small laboratory animal.

Incidence and Risk Factors Associated with Pressure Ulcers among Patients with HIV Infection

OBJECTIVE

To assess the incidence of and risk factors for pressure ulcers among patients with advanced human immunodeficiency virus type 1 (HIV-1) infection.

DESIGN

Multicenter trial that included 1258 consecutive patients infected with HIV-1 who had 1815 admissions to 16 acute care infectious disease units in Italy.

METHODS

Data were collected for demographic, clinical, immunologic, and virologic parameters. The chi-square test was used to compare categorical variables, and the Student t test was used for continuous variables. Univariate analysis was performed to examine possible risk factors for pressure ulcers by computing odds ratios; a multiple logistic regression model was used to obtain adjusted estimates of odds ratios while accounting for all possible risk factors.

RESULTS

The incidence of pressure ulcers was 2.31 per 100 admissions, 3.33 per 100 patients, and 1.06 per 1000 patient days. All stages of pressure ulcers were represented in the sample: 7 Stage I (15.9%), 24 Stage II (54.5%), 8 Stage III (18.2%), and 5 Stage IV (11.4%). Multivariate analyses showed that being female, length of hospitalization, and clinical markers of HIV infection were independently associated with pressure ulcers. Mortality rates were 50% among patients with pressure ulcers and 7.2% among patients without pressure ulcers (P <.0001), with an attributable mortality rate of 42.8% and an odds ratio of 12.96 (95% confidence interval 6.99-24.22).

CONCLUSIONS

A higher incidence of pressure ulcers was found in patients infected with HIV-1 when compared with noninfected patients. Because a longer hospitalization may increase the risk of developing a pressure ulcer, practitioners should be aware of the clinical conditions that may prolong a patient's hospital stay. Aggressive preventive strategies should be implemented to decrease the complications associated with pressure ulcers among patients infected with HIV-1.

Candidemia in Finland, 1995-1999

We analyzed laboratory-based surveillance candidemia data from the National Infectious Disease Register in Finland and reviewed cases of candidemia from one tertiary-care hospital from 1995 to 1999. A total of 479 candidemia cases were reported to the Register. The annual incidence rose from 1.7 per 100,000 population in 1995 to 2.2 in 1999. Species other than Candida albicans accounted for 30% of cases without change in the proportion. A total of 79 cases of candidemia were identified at the hospital; the rate varied from 0.03 to 0.05 per 1,000 patient-days by year. Predisposing factors included indwelling catheters (81%), gastrointestinal surgery (27%), hematologic malignancy (25%), other types of surgery (21%), and solid malignancies (20%). Crude 7-day and 30-day case-fatality ratios were 15% and 35%, respectively. The rate of candidemia increased in Finland but is still substantially lower than in the United States. No shift to non-C. albicans species could be detected.

Bloodstream infections in late-stage acquired immunodeficiency syndrome patients evaluated by a lysis centrifugation system

Opportunistic infections, which affect acquired immunodeficiency syndrome (Aids) patients, are frequently disseminated and may cause bloodstream infections (BSI). The aim of this study was to evaluate the main causes of BSI in Aids patients with advanced stage of the disease, with special emphasis on the identification of fungemia. During a 21 months period, all patients with Aids (CD4 < 200) and febrile syndrome admitted to 3 university hospitals were systematically evaluated. For each patient presenting fever, a pair of blood cultures was collected and processed by using a commercial lysis-centrifugation system. One hundred and eleven patients (75 males) with a mean age of 36 years (median 33 years) and mean CD4 count of 64 cells/ml were included. Among the 111 patients evaluated we documented 54 episodes of BSI, including 46 patients with truly systemic infections and 8 episodes considered as contaminants. BSI were caused by gram-positive bacteria (43%), fungi (20%), gram-negative bacteria (15%), mycobacteria (15%), and mixed flora (7%). The crude mortality rate of our patients was 39%, being 50% for patients with BSI and 31% for the others. In conclusion, BSI are a common related to systemic infections on Aids patients with advanced stage of disease and is associated with a high rate of mortality.

Central line infections

Central venous catheters are commonly used in the critical care setting. Unfortunately, their use is often associated with complications, including fatal infections. Making the diagnosis of central venous catheter infection can be difficult. Additionally, resistance among the more common organisms that cause catheter-related infection is increasing. However, our understanding of the pathogenesis of catheter infection is improving through examination of biofilms. Also, our ability to diagnose catheter-related infections more accurately is improving with new techniques. There is new hope for ruling out catheter-related infection before removal by several methods, including a rapid enzyme-linked immunosorbent assay and the use of time differential for microbial growth between blood cultures obtained from a peripheral site and the catheter itself. Prevention through the use of barrier techniques and antimicrobial-coated catheters has been demonstrated to be of value in reducing catheter-related infection with these devices.