Angelo Pan

Antibiotic Usage and Risk of Colonization and Infection with Antibiotic-Resistant Bacteria: a Hospital Population-Based Study

ABSTRACT Accurate assessment of risk factors for nosocomial acquisition of colonization by antibiotic-resistant bacteria (ARB) is often confounded by scarce data on antibiotic use. A 12-month, nested, multicenter cohort study was conducted. Target ARB were methicillin (meticillin)-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and ciprofloxacin-resistant Pseudomonas aeruginosa (CR-PA). Nares and rectal swabs were obtained before and after starting antibiotics. Pulsed-field gel electrophoresis was done to define genetic relatedness of the strains. Primary outcomes were (i) the mean time, in days, for acquisition of target ARB colonization in patients previously not colonized; (ii) the rate of acquisition per 1,000 antibiotic-days according to different classes of antibiotics; (iii) the rate of infection caused by the same bacteria as those previously isolated in screening samples; and (iv) the risk factors for ARB acquisition. In total, 6,245 swabs from 864 inpatients were processed. The rate of acquisition was 3%, 2%, and 1% for MRSA, VRE, and CR-PA, respectively. The rate of acquisition of ARB per 1,000 antibiotic-days was 14 for carbapenems, 9 for glycopeptides, and 6 for broad-spectrum cephalosporins and quinolones. The highest rates of acquisition were observed for carbapenems in dialyzed and diabetic patients. Four risk factors were independently associated with acquisition of target ARB: use of carbapenems, age of >70 years, hospitalization for >16 days, and human immunodeficiency virus infection. During the 30-day follow-up, 4 among 42 patients newly colonized by ARB (9%) suffered from an infection due to the same bacteria as those isolated in a previous screening sample. Colonizing and infecting strains from single patients were genotypically identical. Identifying ARB colonization early during antibiotic therapy could target a high-risk hospitalized population that may benefit from intervention to decrease the risk of subsequent nosocomial infections.

Nosocomial Bloodstream Infections among Human Immunodeficiency Virus–Infected Patients: Incidence and Risk Factors

To assess the incidence of nosocomial bloodstream infections (NBSIs) in human immunodeficiency virus (HIV)-infected patients, and to analyze the main associated risk factors, we performed a 1-year multicenter prospective study of patients with advanced HIV infection who were consecutively admitted to 17 Italian infectious diseases wards. As of May 1999, a total of 65 NBSIs (4.7%) occurred in 1379 admissions, for an incidence of 2.45 NBSIs per 1000 patient-days. Twenty-nine NBSIs were catheter-related bloodstream infections, with a rate of 9.6 central venous catheter-associated infections per 1000 device-days. Multivariate analysis indicated that variables independently associated with NBSIs included active injection drug use, a Karnofsky Performance Status score of <40, presence of a central venous catheter, and length of hospital stay. Mortality rates were 24.6% and 7.2% among patients with and without NBSIs, respectively (P<.00001). In the era of highly active antiretroviral therapy, NBSIs continue to occur frequently and remain severe and life-threatening manifestations.

Different immunologic profiles characterize HIV infection in highly active antiretroviral therapy-treated and antiretroviral-naive patients with undetectable viraemia

BackgroundSuppression of human immunodeficiency virus (HIV) replication can be obtained in chronically infected individuals by highly active antiretroviral therapy (HAART) and can also be observed in antiretroviral-naïve patients. The immunological correlates of these two situations were examined. Design and methodsCross-sectional study involving 32 HIV-infected patients with undetectable HIV plasma viraemia (< 500 copies/ml) and either antiretroviral-naïve (n = 14) or undergoing HAART therapy with two nucleoside reverse transcriptase inhibitors (NRTI) plus one (n = 13) or two (n = 5) protease inhibitors (PI). CD4 counts, disease duration, and CDC clinical stage were comparable between the two groups of individuals. Immune parameters (antigen- and mitogen-stimulated proliferation and cytokine production; cytokine mRNA; β chemokine production; HIV coreceptors mRNA) were analysed in all patients. ResultsResults showed immune profiles to be profoundly different in antiretroviral-naïve in comparison with HAART-treated patients. Thus: (1) T-cell proliferation to HIV-specific and HIV-unrelated antigens is potent in antiretroviral-naïve but suppressed in HAART-treated individuals; (2) interleukin-(IL)2, IL-12 and interferon gamma (IFNγ) production is robust in naïve patients; and (3) a high CCR5/low CXCR4 pattern of HIV coreceptors-specific mRNA is observed in naïve but not in HAART-treated patients. In contrast with these observations, no clear differences were detected when β chemokine production by either peripheral blood mononuclear cells or purified CD8+ T-cells was analysed. Results from HAART-treated patients undergoing therapy with one PI and two NRTI or two PI and two NRTI were in very close agreement. ConclusionsThese data suggest that control over HIV replication can be independently achieved by pharmacological or immunologic means. HAART is associated with weaker HIV-specific and -non-specific immune responses.

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.

Survival in HIV-Infected Patients after a Cancer Diagnosis in the cART Era: Results of an Italian Multicenter Study

Objectives We studied survival and associated risk factors in an Italian nationwide cohort of HIV-infected individuals after an AIDS-defining cancer (ADC) or non-AIDS-defining cancer (NADC) diagnosis in the modern cART era. Methods Multi-center, retrospective, observational study of HIV patients included in the MASTER Italian Cohort with a cancer diagnosis from January 1998 to September 2012. Malignancies were divided into ADC or NADC on the basis of the Centre for Disease Control-1993 classification. Recurrence of cancer and metastases were excluded. Survivals were estimated according to the Kaplan-Meier method and compared according to the log-rank test. Statistically significant variables at univariate analysis were entered in a multivariate Cox regression model. Results Eight hundred and sixty-six cancer diagnoses were recorded among 13,388 subjects in the MASTER Database after 1998: 435 (51%) were ADCs and 431 (49%) were NADCs. Survival was more favorable after an ADC diagnosis than a NADC diagnosis (10-year survival: 62.7%±2.9% vs. 46%±4.2%; p = 0.017). Non-Hodgkin lymphoma had lower survival rates than patients with Kaposi sarcoma or cervical cancer (10-year survival: 48.2%±4.3% vs. 72.8%±4.0% vs. 78.5%±9.9%; p<0.001). Regarding NADCs, breast cancer showed better survival (10-year survival: 65.1%±14%) than lung cancer (1-year survival: 28%±8.7%), liver cancer (5-year survival: 31.9%±6.4%) or Hodgkin lymphoma (10-year survival: 24.8%±11.2%). Lower CD4+ count and intravenous drug use were significantly associated with decreased survival after ADCs or NADCs diagnosis. Exposure to cART was found to be associated with prolonged survival only in the case of ADCs. Conclusions cART has improved survival in patients with an ADC diagnosis, whereas the prognosis after a diagnosis of NADCs is poor. Low CD4+ counts and intravenous drug use are risk factors for survival following a diagnosis of ADCs and Hodgkin lymphoma in the NADC group.

Efavirenz, nelfinavir, and stavudine rescue combination therapy in HIV-1-positive patients heavily pretreated with nucleoside analogues and protease inhibitors.

Tolerability, activity, and pharmacokinetic parameters of a combination therapy with efavirenz (EFV), nelfinavir (NFV), and stavudine (d4T) were evaluated in this study. Forty-seven HIV-1-infected study subjects, naive to NFV and nonnucleoside reverse transcriptase inhibitors (NNRTIs), who had experienced virologic failure while being treated with combination antiretroviral therapies including protease inhibitors (PIs), were enrolled. At baseline, HIV-1 viral load in plasma was 4.8 log10, CD4+ count was 204 cells/microl (both mean values); patients had received a mean of 3.1 different treatments (range, 2-5 treatments). Study medications were generally well tolerated; 7 of 47 patients (14.8%) were dropped from the study because of related drug toxicity. At week 24, mean plasma viral load (pVL) was reduced by 1.9 log10, with mean CD4+ count increased to 324 cells/microl (+/-59% from baseline); pVL was below the limit of detection (500 copies/ml) in 46.1% of patients. An extended follow-up study was performed at 12 months. Results showed a reduction of 1.7 log10 in pVL from basal values that was consistent with values observed at months 3 and 6. A history of previous use of PIs represented a negative prognostic marker. Sequencing analysis, performed in a subset of patients, showed the presence of multiple point mutations associated with PI resistance. Pharmacokinetic analysis demonstrated a marked interindividual variability in NFV plasma concentrations, producing in 4 of 18 patients (22%) trough concentrations lower than minimum effective concentration. In pretreated patients, further studies are needed to characterize the pharmacokinetic factors that affect response to therapy and the association of these results with the 95% inhibitory concentration (IC95) determined by phenotyping.

Early and late effects of highly active antiretroviral therapy: a 2 year follow-up of antiviral-treated and antiviral-naive chronically HIV-infected patients

BackgroundControl of HIV replication can be observed in highly active antiretroviral therapy (HAART)-treated and, occasionally, in HAART-naive patients. The immunological correlates of these situations were examined in a longitudinal study. DesignA prospective study. Immunovirological analyses in 16 chronically HIV-infected, HAART-naive patients (time 0) who started HAART. Fifteen patients (short-term HAART) were re-evaluated after 24 months (time 1). Results were compared with those of 30 patients who received HAART for more than 12 months before the study period (long-term HAART) and were analysed at the same timepoints. Fifteen patients who were antiviral therapy naive (naive) at both timepoints were also studied. ResultsOver a 24-month period CD4 and CD8 cell counts and viraemia remained unchanged in naive and long-term HAART patients; CD4 cell counts increased and viraemia diminished in short-term HAART individuals. Antigen-stimulated proliferation was unmodified in naive and short-term HAART patients, but improved in long-term HAART individuals. Gp160-stimulated IL-2 and IFN-γ production was augmented in long-term HAART patients and marginally modified in other patients. IL-7 production was unmodified in naive individuals, augmented in short-term HAART patients, and diminished in long-term HAART patients. Chemokine production was similar in all patients. Naive patients showed the highest CD8 cell counts at both timepoints. ConclusionHAART has a major impact on the outcome of HIV infection, even if functional immune modulation in HAART-treated patients is evident only after long periods of therapy. Low but detectable HIV replication in HAART-naive patients with preserved immune functions might not be associated with CD4 cell reduction, functional immune defects, or changes in viraemia.

Quantification of the impact of HIV-1 reverse transcriptase and protease mutations on the efficacy of rescue HAART.

The reduction in the efficacy of rescue treatment (administered on a clinical basis) due to drug resistance was retrospectively quantified in 55 human immunodeficiency virus type 1 (HIV-1)-infected patients failing highly active antiretroviral therapy (HAART) by using a novel score calculation system based upon HIV-1 reverse transcriptase (RT) and protease (PR) mutations. Patients were all naive for nelfinavir (NFV) and efavirenz (EFV) and were assigned to one of the following rescue therapy schedules: (i) 17 patients received NFV + EFV + stavudine (d4T) (group A); (ii) 14 patients received NFV + saquinavir (SQV) + lamivudine (3TC) + d4T/zidovudine (AZT) (group B); (iii) 19 patients received NFV + d4T + didanosine (ddI)/3TC/zalcitabine (ddC) (group C); (iv) five patients received miscellaneous treatments including NFV (group D). Responders were considered patients showing a drop in HIV-1 RNA level > 0.5 log10 after 3 months of therapy. Forty-eight (28 responders and 20 non-responders) out of 55 patients completed the first 3 months of rescue therapy and reduction in HIV-1 viral load was found to be significantly higher in group A compared to groups B and C (81.2% responders vs. 38.5 and 40.0%, respectively). At baseline, no patient carried EFV- or d4T-resistant HIV-1 strains, despite prolonged administration of d4T, while 41/48 (87.2%) patients had mutations conferring resistance to NFV in the absence of previous treatment with this drug. A significant inverse correlation between reduction in viral load and reduction in therapy efficacy due to drug resistance, as determined by the score calculation system, was found (r = 0.62). A cut-off value of 36% reduction in therapy efficacy showed a positive predictive value (capacity to detect failure of rescue treatment) of 81.2% and a negative predictive value (ability to detect successful treatment) of 75.8%. In addition, 45 out of 48 patients completed also the 9-12 month period of rescue therapy and 10/28 responders had a rebound in HIV-1 viral load level detected after the first 3 months of rescue therapy. Of these, 5/7 (71.4%) showed a further reduction in rescue therapy efficacy due to the emergence of new mutations.

Cohort Profile: Standardized Management of Antiretroviral Therapy Cohort (MASTER Cohort)

Cohort Profile: Standardized Management of Antiretroviral Therapy Cohort (MASTER Cohort) Carlo Torti, Elena Raffetti,* Francesco Donato, Francesco Castelli, Franco Maggiolo, Gioacchino Angarano, Francesco Mazzotta, Andrea Gori, Laura Sighinolfi, Angelo Pan, Roberto Cauda, Alfredo Scalzini, Eugenia Quiros-Roldan, Paola Nasta, Giampietro Gregis, Simone Benatti, Simona Digiambenedetto, Nicoletta Ladisa, Mariarosaria Giralda, Annalisa Saracino, Filippo Castelnuovo, Massimo Di Pietro, Sergio Lo Caputo, Giuseppe Lapadula, Silvia Costarelli, Silvia Lorenzotti, Nicola Mazzini, Giuseppe Paraninfo, Salvatore Casari, Emanuele Focà, Chiara Pezzoli, Massimiliano Fabbiani, Laura Monno, Piera Pierotti, Claudio Ble, Sebastiano Leone, Maria Concetta Postorino, Chiara Fornabaio, Fabio Zacchi, Alessia Zoncada and Giampiero Carosi Unità di Malattie Infettive e Tropicali, Dipartimento di Scienze Mediche e Chirurgiche, Università Magna Grecia di Catanzaro, Catanzaro, Italia, Unità di Igiene, Epidemiologia e Sanità Pubblica, Università degli Studi di Brescia, Brescia, Italia, Divisione Universitaria di Malattie Infettive Spedali Civili di Brescia-Università degli Studi di Brescia, Brescia, Italia, Malattie Infettive Ospedale Papa Giovanni XXIII, Bergamo, Italia, Clinica di Malattie Infettive Policlinico di Bari, Bari, Italia, Malattie Infettive S.M. Annunziata, Firenze, Italia, Malattie Infettive Ospedale San Gerardo di Monza, Monza, Italia, Malattie Infettive Nuovo Polo Ospedaliero di Cona, Ferrara, Italia, Malattie Infettive Istituti Ospitalieri di Cremona, Cremona, Italia, Clinica di Malattie Infettive Policlinico A. Gemelli-Università Cattolica di Roma, Roma, Italia, Divisione Ospedaliera di Malattie Infettive Spedali Civili, Brescia, Italia and Fondazione Malattie Infettive e Salute Internazionale, Brescia, Italia

Surgical site infections in HIV-infected patients: results from an Italian prospective multicenter observational study.

Background:The quality of life of the HIV-infected population in developed countries has substantially improved over the years. Accordingly, the clinical limitations in the surgical treatment of the HIV-infected patients are becoming fewer, and the number of HIV-infected patients undergoing surgical interventions of all types is increasing. However, available data on the incidence and risk factors for post-surgical complications, such as surgical site infections (SSI), in HIVinfected patients are still limited and often controversial. The aim of this study was to determine the incidence and the associated risk factors for SSI in HIV-infected patients.Methods:A 1-year observational prospective multicenter surveillance study was conducted in 11 Italian Infectious Diseases Clinical Centers from which 305 consecutive HIVinfected patients undergoing different surgical procedures were enrolled. Postdischarge surveillance was conducted within 30 days after surgery. A number of variables were included in a multivariate analysis aimed at assessing potential risk factors for SSI, including body mass index, diabetes, Hepatitis C (HCV) and hepatitis B virus infection, lipodistrophy, HIV viral load, CD4 cell count and white blood cell count, preoperative hospital stay, National Nosocomial Infection Surveillance (NNIS) risk score, and any antimicrobial prophylaxis.Results:SSI occurred in 29 of 305 (9.5%) patients, of which 17 (58.6%) SSI occurred during hospital stay, and 12 (41.4%) occurred during the postdischarge period. The SSI of the 29 patients were classified as superficial (21, 72.4%), deep (four, 13.8%), organ/space (one, 3.4%), and sepsis (three, 10.3%). Nearly 50% of the superficial and 50% of the deep SSI occurred during the postdischarge period. Organ/space infection and sepsis accounted for 13.7% of all SSI and were observed during the in-hospital stay. The multivariate analysis revealed that HCV co-infection was significantly associated to SSI occurrence. Total hospital stay was longer among patients with SSI than among those without SSI (p = 0.041).Conclusion:Although 92.5% of our HIV-infected patients presented a NNIS score ≤ 1, the SSI rate was twofold higher than that reported in Italian and European studies for the general population, with more severe clinical presentations. This is the first report of an association between HCV–HIV co-infection and SSI occurrence. Additionally, the viroimmunological status of our patients was not related to SSI occurrence, which suggests the need for further research for other potential risk factors that may be implicated in the occurrence of SSI.