Liana Signorini

Recent changes in bacterial epidemiology and the emergence of fluoroquinolone-resistant Escherichia coli among patients with haematological malignancies: results of a prospective study on 823 patients at a single institution

BACKGROUND Regular monitoring of bacterial epidemiology allows evaluation of antibacterial strategies adopted. The aim of this study was to disclose evolving trends in the epidemiology of infections and emerging antibiotic resistance in unselected inpatients with haematological cancers. METHODS Febrile/infectious episodes occurring in 823 patients consecutively admitted to a single institution during a 16 month period were analysed. Levofloxacin prophylaxis was used in patients with >7 days expected neutropenia. RESULTS Fever developed in 364 patients (44.2%) and an infection was documented in 187 (22.7%), either clinically (6.1%) or microbiologically (16.6%). Levofloxacin prophylaxis, used in 39.4% of cases, caused a reduction in febrile episodes only among neutropenic patients and no difference in the frequency of documented infections. Among 164 pathogens isolated, gram-negative (49.4%) outweighed gram-positive bacteria (40.9%), Escherichia coli being most frequent (23.2%). Fluoroquinolone resistance and methicillin resistance were the most frequent types of antibiotic resistance, occurring in 56.1% of bacterial isolates and in 66.7% of staphylococci, respectively. Fluoroquinolone-resistant E. coli accounted for 20.1% of all isolates and for 86.8% of E. coli. Multivariate analysis of risk factors for fluoroquinolone resistance identified prophylaxis (P < 0.001) and neutropenia >7 days (P = 0.02) as independent. Methicillin resistance was independently associated with prophylaxis (P = 0.041) and central venous catheters (P = 0.036). Infections by fluoroquinolone-resistant strains did not show a worse outcome. CONCLUSIONS A shift towards gram-negative bacteria has been occurring in recent years in the bacterial epidemiology of haematological patients. Fluoroquinolone resistance is emerging as a major type of antibacterial resistance, particularly among E. coli strains. Further investigation is needed to explore the consequences of such epidemiological changes.

Adherence to hand hygiene in an Italian long-term care facility

In an Italian long-term-care facility (LTCF), we observed a 17.5% adherence to hand hygiene (HH), as well as 47.5% rate of glove use. Performing a procedure at high risk for cross-transmission of germs was the factor most strongly associated with noncompliance (odds ratio = 13.3; 95% confidence interval = 6.2 to 28.8; P < .0001). No significant differences in compliance related to health care worker category were found. Adherence to HH in the LTCF was similar to that found in a rehabilitation medicine unit of an acute care hospital (15.8%) but significantly lower than that reported in an infectious disease unit (53.7%; P < .0001). Our findings indicate that compliance with HH is a similar problem in LTCFs as in acute care facilities.

Recent increase in enterococci, viridans streptococci, Pseudomonas spp. and multiresistant strains among haematological patients, with a negative impact on outcome. Results of a 3-year surveillance study at a single institution

Abstract We prospectively analysed the microbiological isolates of all febrile/infectious episodes occurring at our haematology unit during 2 consecutive 18-month periods. Microbiologically documented infections (MDI) and antibiotic resistance were correlated with type and status of haematological disease, neutropenia, levofloxacin prophylaxis, central venous catheter and clinical outcome. Three hundred and ten MDI were observed and 369 pathogens were isolated. Gram-negative bacteria represented 49.3% and Gram-positive bacteria 40.9% of all pathogens. Fungal infections represented only 8.9% of MDI. A significant decrease in Staphylococcus aureus (p < 0.001) and an increase in enterococci, viridans streptococci and Pseudomonas spp. (p = 0.004) were observed during the second period. Four multiresistant (Multi-R) Pseudomonas were isolated, all during the last 12 months. The death rate in MDI was 8.7%, bacteria accounting for 70.4% of them. Enterococci, streptococci and Pseudomonas spp. infections were involved in 44.4% of MDI with an unfavourable outcome. Multi-R pathogens were involved in 4 cases (3 vancomycin-resistant enterococci and 1 Multi-R Pseudomonas), their death rate being 25%. Multivariate analysis showed that an infection due to a mycotic or a Multi-R pathogen was associated with an unfavourable outcome. The recent emergence of enterococci, viridans streptococci and Pseudomonas spp., particularly if Multi-R, is a major concern in haematological patients.

Methicillin-resistant Staphylococcus aureus ST398, Italy.

To the Editor: It has recently become apparent that livestock can constitute a new methicillin-resistant Staphylococcus aureus (MRSA) reservoir and be a source of a novel and rapidly emerging type of MRSA. These livestock-associated MRSA clones are nontypeable by use of pulsed-field gel electrophoresis with SmaI and belong to sequence type (ST) 398 (1). MRSA ST398 clones account for 20% of all MRSA in the Netherlands (2), but the emergence of such clones has been described worldwide (3). Although ST398 transmission has been reported primarily between animals, persons with occupational exposure to livestock are at higher risk for MRSA carriage than the general population. Even though MRSA ST398 usually causes colonization, several cases of infections of variable clinical relevance, varying from skin and soft tissue infections (4) to endocarditis (5) and pneumonia (6), have been described over the past few years. Most instances of ST398 human carriers have been identified among persons who work at pig farms (7). Data regarding MRSA colonization of dairy farmers are less exhaustive and, to our knowledge, only 1 instance of direct transmission between cattle and humans has been proven. MRSA isolates from cows with subclinical mastitis in 2007 in Hungary were indistinguishable from MRSA isolates from the tonsil swab of a farmer who worked with these animals (8). We report a case of MRSA ST398 invasive disease in a cattle farmer, as well as a case of MRSA ST398 necrotizing fasciitis. In early April 2008, a 52-year-old man was admitted to an intensive care unit in Manerbio, Italy, because of severe sepsis and a large ulcerative and suppurative lesion on the right side of his neck. His medical history was unremarkable. He was a worker at a dairy farm, was obese, and did not report any previous contact with the healthcare system. At the time of hospital admission, he was oriented and cooperative. His temperature was 38.4°C, heart rate was 125 beats per minute, and blood pressure was 165/75 mm Hg. Arterial blood gas analysis showed hypoxemia and mild hypocapnia (PaO2 53 mm Hg and PaCO2 33.8 mm Hg on room air). Leukocyte count was 21,280 cells/μL (81.9% polymorphonuclear cells), and platelet count was 310,000 cells/μL. After blood samples were collected and aggressive surgical debridement of affected tissue was performed, empirical treatment with intravenous teicoplanin and imipenem was started. On the basis of histologic appearance of the intraoperative material and computed tomography scan images, necrotizing fasciitis was diagnosed. Culture of blood and necrotic tissue yielded MRSA. On day 3 after admission, antimicrobial drug therapy was changed to teicoplanin and clindamycin and, on day 7, to linezolid. Fever resolved in 3 days and the patient’s condition progressively improved. The patient was discharged after 31 days of antimicrobial drug therapy. The MRSA isolate was susceptible to all the non–β-lactam antimicrobial drugs tested (excluding tetracycline), carried the staphylococcal cassette chromosome mec type V, and was negative for Panton-Valentine leukocidin (PVL) genes. Multilocus sequence typing and sequence typing of the tandem repeat region of protein A gene (spa typing) showed that the isolate belonged to ST398 and spa type 899, respectively. Some issues are of concern. Although the MRSA isolate was PVL negative, its virulence resembled that of PVL-positive strains. Furthermore, it was resistant to tetracycline, as we expected because oxytetracyclines are the antimicrobial drugs most frequently used in pig and cattle farming (3). The major limitation of our study was that data regarding MRSA colonization of the farm are missing, so cattle-to-human transmission cannot be proven. However, because our patient did not have any other potential risk factor, dairy cows were probably the source of the human infection. In countries where community-acquired MRSA is common, all patients with serious S. aureus infections should be treated for MRSA until antimicrobial susceptibilities are known. Our report suggests that even in countries where community-acquired MRSA is still rare, being a cattle farmer may be considered an indication for early treatment against MRSA. The expanding knowledge of this zoonotic potential may undermine existing nosocomial MRSA control programs. In countries where a search and destroy policy (9) is adopted, such as the Netherlands, pig and cattle farmers may warrant screening and isolation at the time of hospital admission. Nevertheless, the first MRSA ST398 nosocomial outbreak has already been described (10). It is difficult to prevent persons with constant exposure to MRSA in their work or home setting from becoming MRSA carriers. Revisiting policies for the use of antimicrobial drugs on livestock farms, as well as improving hygiene measures, may therefore be necessary in infection control programs. However, before final recommendations can be made, further investigation is needed to determine the prevalence of MRSA among livestock and their handlers.

Antibiotic Lock-Technique for the Treatment of Catheter-Related Bloodstream Infections

Abstract The management of central venous catheter-related bloodstream infections (CRBSI), though still debated, requires the removal of the line in most cases: we investigated the efficacy of an alternative approach, based on higher concentrations of antibiotics locked within the catheter lumen, in an open, pilot study aimed at preserving the line in place and at eradicating the infection. Thirty consecutive patients carrying a central line over 10 days and who fulfilled criteria for ascertained diagnosis of bacterial CRBSI, had the catheter “locked” with antimicrobials therein; all patients also received systemic antibiotic therapy within the first 48 hours. Subsequently, 15 patients underwent locks alone, and 15 locks plus systemic therapy. Twenty-eight out of 30 (93.3%) patients retained the catheter in place, appearing to be cleared of infection and no treatment-related untoward events were observed. Locks should be considered as effective as line removal in the management of bacterial CRBSI in unselected patients, and could thus provide advantages in terms of resource sparing and lowered antibiotic pressure in the hospital setting.

Clinical stability in human immunodeficiency virus-infected patients with community-acquired pneumonia

Clinical stability (CS), defined as normalization of vital signs, is often used to manage inpatients with community-acquired pneumonia (CAP). The main objective of our study was to identify a reliable definition of CS for human immunodeficiency virus (HIV)-positive patients with CAP. During an 18-month period, 437 HIV-positive Italian inpatients with CAP were enrolled in the study. We used 3 definitions of CS (from a less conservative [definition 1] to a more conservative [definition 3] definition) based on combinations of different thresholds for vital signs. Assessments were performed at admission and daily during the hospital stay. For the 3 definitions, 14.9%, 8.0%, and 4.8% of patients were stable at baseline, with deterioration after reaching CS in 7.16%, 4.76%, and 2.05%, respectively. The 8 patients whose conditions deteriorated after reaching CS definition 3 (systolic blood pressure, >90 mm Hg; pulse, <90 beats/min; respiratory rate, <20 breaths/min; oxygen saturation, >90%; temperature, <37 degrees C; ability to eat; and normal mental status) survived and were discharged from the hospital. The more conservative definition of CS appears to be reliable for the management of HIV-infected patients with CAP.

Risk Factors and Clinical Characteristics Associated with Hospitalization for Community-Acquired Bacterial Pneumonia in HIV-Positive Patients According to the Presence of Liver Cirrhosis

AbstractBackground:Community-acquired bacterial pneumonia (CABP) represents an important cause of morbidity and mortality for cirrhotic and HIV-infected patients, respectively. However, little is known on CABP in HIV-positive patients with cirrhosis. A study was performed to describe the clinical features and factors predictive of mortality and prolonged hospitalization in cirrhotic HIV-infected patients with a diagnosis of CABP.Methods:Demographic and clinical characteristics of cirrhotic HIV-positive subjects, hospitalized for CABP in our department from June 2000 to December 2006, were compared with those of non-cirrhotic HIV-infected patients with the same diagnosis hospitalized from June 2000 to November 2001. Variables with p < 0.10 in univariate analysis were tested for their predictive value for mortality and length of hospitalization with uni- and multivariate logistic regression analysis.Results:Twenty-nine cirrhotic and 73 non-cirrhotic HIV-positive patients with CABP were compared. Age and alcohol abusewere significantly higher in cirrhotics. At hospital admission, cirrhotic patients had more frequently mental status alterations (7.26 [2.21–23.82], p = 0.001) and milder symptoms and signs (temperature > 37.5 _C: 0.27 [0.10–0.75], p = 0.01; respiratory rate > 20: 0.34 [0.13–0.92], p = 0.033; systemic inflammatory response syndrome (SIRS): 0.39 [0.16–0.95], p = 0.038). Adjusting for age, cirrhosis was associated with a higher mortality (5.96 [1.05–33.57]; p = 0.043). Adjusting for age, gender, and concomitant antiretroviral treatment, cirrhosis was also associated with a prolonged hospitalization (> 7 days: 9.30 [1.84–46.82]; p = 0.007).Conclusion:The diagnosis of CABP can be difficult in cirrhotic HIV-positive patients because clinical presentation is milder. However, CABP needs to be promptly recognized because mortality is higher in these patients.

Fatal Disseminated Toxoplasmosis During Primary HIV Infection

Toxoplasmosis is a well recognized manifestation of AIDS, but the disseminated disease is a rare condition and it has not been associated to HIV seroconversion to our knowledge. We describe a fatal episode of disseminated T. gondii acute infection with massive organ involvement during primary HIV infection. The serological data demonstrate primary T. gondii infection. The avidity index for HIV antibodies supports recent HIV-1 infection.

A Case of Melioidosis Probably Acquired by Inhalation of Dusts During a Helicopter Flight in a Healthy Traveler Returning From Singapore

We present a case of melioidosis in an Italian male returning from Singapore after a short travel. He probably acquired the disease by inhalation, which is not the typical mode of transmission, in the absence of evident risk factors. The diagnosis was confirmed by real-time polymerase chain reaction of the culture while serology was useful to assess professional exposure among laboratory workers. Treatment consisted of an initial intensive phase with meropenem and trimethoprim-sulfamethaxazole (TMP-SMX), followed by 6 months of eradication therapy with TMP-SMX.

Adherence to surgical site infection guidelines in Italian cardiac surgery units.

Background:Data on the adherence to surgical site infection (SSI) prevention guidelines in Italian cardiac surgery units are lacking.Methods:A multiple-choice questionnaire, structured into eight sections following the Centers for Disease Control 1999 (CDC) guidelines, was prepared and sent to 24 surgical units participating in a national study group (GIS-InCard); this units perform over 20% of all cardiac surgical procedures in Italy. Answers were stratified based upon the evidence of the recommendations: grade IA (ten questions), grade IB (52 questions), grade II (11 questions), and no recommendation (seven questions).Results:17 of the 24 units (72%) returned the questionnaire. Adherence to grade IA recommendations was 69 ± 34%, with five units (29%) showing a ≥80% adherence. Adherence to grade IB and II was 65 ± 26% and 71 ± 28%, respectively. Adherence did not vary significantly depending on the evidence of the recommendation, i.e., grade IA, IB or II (p = 0.72). Low adherence levels to grade I recommendations were observed on hair removal: (1) it was performed systematically in all male patients (0% adherence), (2) it was performed on the morning of the intervention in 29% of centers, and (3) the method of hair removal was adequate in 41% of cases. Despite 94% of units having written guidelines on antibiotic prophylaxis, only 65% administered antibiotic prophylaxis with the correct timing – i.e., on anesthesia induction.Conclusions:Adherence to CDC SSI guidelines in Italy is fair. The evidence of the recommendation does not influence adherence. Organizational improvements, especially those regarding hair removal and the timing of antibiotic prophylaxis, should be implemented in most hospitals.