Prior Colonization Research Articles

Administration of non-pathogenic isolates of Escherichia coli and Clostridium perfringens type A to piglets in a herd affected with a high incidence of neonatal diarrhoea

A bacterial cocktail of living strains of Clostridium perfringens type A (CPA) without β2-toxin gene and non-pathogenic Escherichia coli was administered orally to newborn piglets before first colostrum intake and on 2 consecutive days on a farm with a high incidence of diarrhoea and antibiotic treatment in suckling piglets associated with E. coli and CPA. This clinical field study was driven by the hypothetic principle of competitive exclusion of pathogenic bacteria due to prior colonization of the gut mucosal surface by non-pathogenic strains of the same bacterial species with the aim of preventing disease. Although CPA strains used in this study did not produce toxins in vitro, their lack of pathogenicity cannot be conclusively confirmed. The health status of the herd was impaired by a high incidence of postpartum dysgalactia syndrome in sows (70%) and a high incidence of neonatal diarrhoea caused by enterotoxigenic E. coli and CPA during the study. No obvious adverse effect of the bacterial treatment occurred. On average, more piglets were weaned in litters treated (P=0.009). Visual pathological alterations in the small intestinal wall were more frequent in dead piglets of the control group (P=0.004) and necrotizing enteritis was only found in that group. A higher average daily weight gain of piglets in the control group (P<0.001) may be due to an increased milk uptake due to less competition in the smaller litters. The bacterial cocktail was tested under field conditions for its potential to stabilize gut health status in suckling piglets before disease development due to colibacillosis and clostridial infections; however, the gut flora stabilizing effect of the bacterial cocktail was not clearly discernible in this study. Further basic research is needed to confirm the positive effects of the bacterial treatment used and to identify additional potential bacterial candidates for competitive exclusion.

Risk Factors for Surgical Site Infections Following Neurosurgical Spinal Fusion Operations: A Case Control Study.

OBJECTIVE To determine risk factors for the development of surgical site infections (SSIs) in neurosurgery patients undergoing spinal fusion. DESIGN Retrospective case-control study. SETTING Large, academic, quaternary care center. PATIENTS The study population included all neurosurgery patients who underwent spinal fusion between August 1, 2009, and August 31, 2013. Cases were defined as patients in the study cohort who developed an SSI. Controls were patients in the study cohort who did not develop an SSI. METHODS To achieve 80% power with an ability to detect an odds ratio (OR) of 2, we performed an unmatched case-control study with equal numbers of cases and controls. RESULTS During the study period, 5,473 spinal fusion procedures were performed by neurosurgeons in our hospital. With 161 SSIs recorded during the study period, the incidence of SSIs associated with these procedures was 2.94%. While anterior surgical approach was found to be a protective factor (OR, 0.20; 95% confidence interval [CI], 0.08-0.52), duration of procedure (OR, 1.58; 95% CI, 1.29-1.93), American Society of Anesthesiologists score of 3 or 4 (OR, 1.79; 95% CI, 1.00-3.18), and hospitalization within the prior 30 days (OR, 5.8; 95% CI, 1.37-24.57) were found in multivariate analysis to be independent predictors of SSI following spinal fusion. Prior methicillin-resistant Staphylococcus aureus (MRSA) nares colonization was highly associated with odds 20 times higher of SSI following spinal fusion (OR, 20.30; 95% CI, 4.64-8.78). CONCLUSIONS In additional to nonmodifiable risk factors, prior colonization with MRSA is a modifiable risk factor very strongly associated with development of SSI following spinal fusion. Infect Control Hosp Epidemiol 2017;38:348-352.

Intensive care unit-acquired pneumonia due to Pseudomonas aeruginosa with and without multidrug resistance

Pseudomonas aeruginosa often presents multi-drug resistance (MDR) in intensive care unit (ICU)-acquired pneumonia (ICUAP), possibly resulting in inappropriate empiric treatment and worse outcomes. We aimed to identify patients with ICUAP at risk for these pathogens in order to improve treatment selection and outcomes. We prospectively assessed 222 consecutive immunocompetent ICUAP patients confirmed microbiologically. We determined the characteristics, risk factors, systemic inflammatory response and outcomes of P. aeruginosa pneumonia (Pa-ICUAP), compared to other aetiologies. We also compared patients with MDR vs. non-MDR Pa-ICUAP. Pseudomonas aeruginosa was the most frequent aetiology (64, 29%); 22 (34%) cases had MDR. Independent predictors for Pa-ICUAP were prior airway colonization by P. aeruginosa, previous antibiotic treatment, solid cancer and shock; alcohol abuse and pleural effusion were independently associated to lower risk for Pa-ICUAP. Chronic liver disease independently predicted MDR among Pa-ICUAP. The inflammatory biomarkers were similar between all groups. Patients with Pa-ICUAP had lower unadjusted 90-day survival (p=0.049). However, the 90-day survival adjusted for confounding factors using a propensity score did not differ between all groups. Pseudomonas aeruginosa remains the most frequent aetiology of ICUAP, with high prevalence of MDR. These risk factors should be taken into account to avoid inappropriate empiric antibiotics for Pa-ICUAP. Pseudomonas aeruginosa, regardless multidrug resistance, was not associated with different propensity-adjusted survival.

Small Intestine Early Innate Immunity Response during Intestinal Colonization by Escherichia coli Depends on Its Extra-Intestinal Virulence Status.

Uropathogenic Escherichia coli (UPEC) strains live as commensals in the digestive tract of the host, but they can also initiate urinary tract infections. The aim of this work was to determine how a host detects the presence of a new UPEC strain in the digestive tract. Mice were orally challenged with UPEC strains 536 and CFT073, non-pathogenic strain K12 MG1655, and ΔPAI-536, an isogenic mutant of strain 536 lacking all 7 pathogenicity islands whose virulence is drastically attenuated. Intestinal colonization was measured, and cytokine expression was determined in various organs recovered from mice after oral challenge. UPEC strain 536 efficiently colonized the mouse digestive tract, and prior Enterobacteriaceae colonization was found to impact strain 536 colonization efficiency. An innate immune response, detected as the production of TNFα, IL-6 and IL-10 cytokines, was activated in the ileum 48 hours after oral challenge with strain 536, and returned to baseline within 8 days, without a drop in fecal pathogen load. Although inflammation was detected in the ileum, histology was normal at the time of cytokine peak. Comparison of cytokine secretion 48h after oral gavage with E. coli strain 536, CFT073, MG1655 or ΔPAI-536 showed that inflammation was more pronounced with UPECs than with non-pathogenic or attenuated strains. Pathogenicity islands also seemed to be involved in host detection, as IL-6 intestinal secretion was increased after administration of E. coli strain 536, but not after administration of ΔPAI-536. In conclusion, UPEC colonization of the mouse digestive tract activates acute phase inflammatory cytokine secretion but does not trigger any pathological changes, illustrating the opportunistic nature of UPECs. This digestive tract colonization model will be useful for studying the factors controlling the switch from commensalism to pathogenicity.

Epidemiology of febrile neutropenia in patients with hematological disease-a prospective multicentre survey in China

目的了解中国血液病患者中性粒细胞缺乏（粒缺）伴发热的发生率、临床和微生物学特征及危险因素。方法前瞻性研究2014年10月20日至2015年3月20日来自全国11家血液病中心发生粒缺伴发热的连续血液病患者发热情况及危险性因素。结果1 139例患者共发生784例次粒缺伴发热，粒缺持续21 d时发热的累积发生率为81.9%。多因素分析显示中心静脉置管（P<0.001，HR= 3.407，95% CI 2.276~4.496）、胃肠道黏膜炎（P<0.001，HR=10.548, 95% CI 3.245~28.576）、既往90 d内暴露于广谱抗生素（P<0.001，HR=3.582，95% CI 2.387~5.770）和粒缺持续时间>7 d（P<0.001，HR= 4.194，95% CI 2.572~5.618）是粒缺伴发热的危险因素。无任何危险因素、具备1项、2项、3~4项危险因素患者发热的累计发生率依次增加（35.4%、69.2%、86.1%及95.6%，P<0.001）。784例次粒缺伴发热中，不明原因发热253例次（32.3%），临床证实的感染429例次（54.7%），微生物学证实的感染102例次（13.0%）。最常见的感染部位依次为肺（388例次，49.5%）、上呼吸道（159例次，16.0%）、肛周组织（77例次，9.8%）、血流（60例次，7.7%）。最常见的病原菌为革兰阴性菌（44.54%），其次为革兰阳性菌（37.99%）和真菌（17.47%）。发热与未发热患者相比，两组之间总体病死率差异无统计学意义（9.2%对4.8%，P=0.099）。多因素分析显示年龄>40岁（P=0.047，HR=5.000，95% CI 0.853~28.013）、血流动力学不稳（P=0.001，HR=13.185, 95% CI 2.983~54.915）、既往耐药菌的定植或感染（P=0.005，HR=28.734，95% CI 2.921~313.744）、血流感染（P=0.038，HR=9.715, 95% CI 1.110~81.969）和肺部感染（P=0.031，HR=25.905, 95% CI 1.381~507.006）是与总体死亡相关的危险因素。结论发热是血液病患者粒缺期常见的合并症，不同部位的感染有不同的致病菌谱。粒缺持续时间>7 d、中心静脉置管、胃肠道黏膜炎和既往90 d内暴露于广谱抗生素是粒缺伴发热发生的危险因素。

Scanning Electron Microscopic Analysis of Biofilm Formation in Explanted Human Boston Type I Keratoprostheses.

To describe the morphological distribution of host tissue and microbial biofilms on the intraocular surfaces of Boston type I keratoprostheses (KPros) explanted because of corneal melt. Retrospective study of scanning electron microscopy (SEM) images from 4 explanted Boston type I KPros composed of polymethylmethacrylate and titanium. SEM images of KPro-associated ocular surfaces were reviewed for the presence of inflammatory cells, microbes, and/or biofilm formation. One sterile type I KPro was also imaged to serve as a (device only) control. All 4 KPros were explanted because of culture-negative, clinically "sterile" donor corneal melt with impending KPro extrusion. In all cases, the rough, irregular surfaces of the device harbored more adherent corneal epithelium and stromacytes, inflammatory cells, and bacteria than the smooth, polished surface of the KPro optic. Two KPros showed not only evidence of prior bacterial colonization but marked biofilm formation. SEM images of explanted KPros explanted for "sterile" corneal melt demonstrated evidence of biofilm formation despite negative donor corneal cultures and the absence of clinical suspicion for infection. These results suggest that "sterile" corneal melt may be due to inflammatory host responses to low microbial burdens as seen in biofilms and/or released antigens after antibiotic-induced lysis. There was increased adherence of host tissue cells and microbial biofilms on the nonpolished surfaces of the KPro. Polishing the intraocular polymethylmethacrylate and titanium KPro surfaces may decrease microbial adhesion and biofilm formation in human subjects with KPros, but what impact this will have on rates of postoperative endophthalmitis is unknown.

The efficiency of routine endotracheal aspirate cultures compared to bronchoalveolar lavage cultures in ventilator-associated pneumonia diagnosis.

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in İntensive Care Units (ICUs) and its mortality rate varies from 24% to 50%. The most important factor in decreasing the mortality is administering adequate antibiotics as early as possible. In this study, we investigate the efficiency of routine endotracheal aspirate (EA) cultures to identify the etiology of VAP earlier. Fifty-nine patients who were accepted to our ICU with acute cerebrovascular disease with mechanical ventilation (MV) requirement were chosen for this study over a 12-month period. The patients intubated in our ICU were included in the study to exclude prior colonization. Upon ICU admission, the patient's; age, sex, comorbidities, diagnosis, acute physiology and chronic health evaluation II score, and sequential organ failure assessment (SOFA) score were recorded. When bronchoalveolar lavage (BAL) was performed, the SOFA score, temperature, leukocyte count, C-reactive protein levels, PaO2/FiO2ratio, PCO2, clinical pulmonary infection score value, length of MV, and presence of antimicrobiological treatments were recorded. Routine microbiological analysis was performed by EA (pre-VAP EA) twice weekly in all patients until the endotracheal tube was removed. When VAP was suspected, fiberoptic bronchoscopy examination with BAL was performed. A diagnosis of VAP was established when the BAL quantitative culture grew at least one microorganism at a concentration ≥104 cfu/mL. VAP was diagnosed in 41 (69%) of the 59 patients based on BAL culture results. Among 41 positive BAL cultures, pre-VAP EA identified the same microorganism with the same antibiotics resistance pattern in 23 (56%) patients. Regarding only late-onset VAP, pre-VAP EA identified the same microorganisms found by BAL culture in 17 (63%) of the 27 cases. Among 18 BAL culture negative patients, 7 (39%) patients had negative prior pre-VAP EA culture results. Acinetobacter baumannii was the most frequently isolated microorganism from BAL cultures (n = 21, 51%). The diagnostic value of pre-VAP EA results in predicting A. baumannii VAP documented with the following values (sensitivity: 62%; specificity: 95%, positive predictive value: 87%, negative predictive value: 82%). VAP patients should be treated with international guidelines, but if pre-VAP EA cultures identify multidrug resistant pathogens, the initial antibiotic therapy should cover these microorganisms. Thus, quantitative EA cultures are a useful noninvasive diagnostic tool in critically ill patients suspected of having pneumonia especially in the case of VAP.

Management of invasive fungal infections in the pediatric intensive care unit

Invasive candidiasis (IC) are the most common invasive fungal infections in pediatric intensive care unit patients due to commonly present risk factors including central venous catheters, antibiotic exposure, recent surgery, total parenteral nutrition, and prior colonization with Candida species. These infections are economically costly and have been associated with an attributable mortality of approximately 10%. As a result, investigators have attempted to identify cohorts of pediatric intensive care unit patients at highest risk of development of IC who may benefit from prophylactic, early empiric, or pre-emptive therapy. This review article will consider these prediction models and therapeutic approaches. Additionally, the management of confirmed IC, including anti-fungal therapeutic options, evaluation for disseminated disease, and management of central venous catheters, will be reviewed.

Is there a relationship between rectal colonization and nosocomial infection of patients in intensive care unit?

Nosocomial infections caused by multidrug-resistant (MDR) microorganisms are a major problem in intensive care units (ICUs) with high mortality and morbidity rates and the prior colonization is an important risk factor for these infections. The aim of this study was to investigate the prevalence of rectal colonization of MDR microorganisms and the association between the microorganisms that caused colonization and infection in the patients with nosocomial infections in ICUs. Rectal swabs were obtained on the day of 0, 3, 7, 14, 21 and weekly thereafter from 80 patients over 18 years of age hospitalized in ICU for more than 48 hours, and cultured for vancomycin-resistant enterococcus (VRE), methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamase (ESBL)- producing gram-negative bacilli (GNB) and carbapenem-resistant enteric and nonenteric bacilli. Patients whose rectal swabs were not obtained on admission (on the day of 0), were excluded even they were hospitalized more than 48 hours. Bile esculin agar containing 64 μg/mL ceftazidime and 6 μg/mL vancomycin, chromogenic MRSA agar and blood agar media, MacConkey agar containing 1 mg/L ceftazidime and ceftriaxone, and 5 mL tryptic soy broth media containing 10 µg imipenem and meropenem discs were used for identification. Identification of GNB was determined by conventional methods and ESBL production was determined by double-disc synergy test. Patients have been followed up for nosocomial infections. Bacterial identification and antibiotic susceptibility tests were performed with standard microbiological methods. In 37 (46%) of the 80 patients, at least one MDR microorganism was isolated in rectal swab cultures on the day of 0. The most common microorganisms were ESBL-positive E.coli (19%), followed by ESBL-positive K.pneumoniae (13%), carbapenem-resistant P.aeruginosa (10%), ESBL-positive K.oxytoca (3%), MRSA (1%), VRE (1%), carbapenem-resistant Acinetobacter sp. (1%) and carbapenem-resistant K.pneumoniae (1%), respectively. The number of microorganisms isolated from rectal swab cultures on the following days have increased, and on the 7th day, the rate of the patients with rectal colonization ascended to 72%. Out of 80 patients, 52 (65%) had nosocomial infections in the follow-up and the mean duration of infection development was 11.8±9.9 days in these patients. Patients with and without rectal colonization were compared in terms of subsequent nosocomial infection rates. While no statistically significant difference has been detected between two groups on the day of 0, patients with rectal colonization detected on the day of 3 and 7, had a significantly higher incidence of nosocomial infections (p=0.02, p=0.01). Among the patients with ESBL-positive GNB, carbapenem-resistant K.pneumoniae, carbapenem-resistant P.aeruginosa and VRE infections, the same microorganisms have been isolated in the rectal swab cultures taken before the development of infection. This result was statistically significant for each of these microorganisms (p=0.00-0.03). However, such a correlation was not observed for Acinetobacter infections. Since MRSA infections developed in only two patients, no istatistical analysis has been done for this microorganism. In conclusion, our data suggest that MDR microorganisms that cause nosocomial infections, initially colonize the gastrointestinal tract, and early detection of colonized patients in ICUs may help an effective infection control by preventing the spread of these resistant microorganisms.

Nasal carriers are more likely to acquire exogenous Staphylococcus aureus strains than non-carriers

We performed a prospective observational study in a clinical setting to test the hypothesis that prior colonization by a Staphylococcus aureus strain would protect, by colonization interference or other processes, against de novo colonization and, hence, possible endo-infections by newly acquired S. aureus strains. Three hundred and six patients hospitalized for >7 days were enrolled. For every patient, four nasal swabs (days 1, 3, 5, and 7) were taken, and patients were identified as carriers when a positive nasal culture for S. aureus was obtained on day 1 of hospitalization. For all patients who acquired methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus via colonization and/or infection during hospitalization, strains were collected. We note that our study may suffer from false-negative cultures, local problems with infection control and hospital hygiene, or staphylococcal carriage at alternative anatomical sites. Among all patients, 22% were prior carriers of S. aureus, including 1.9% whom carried MRSA upon admission. The overall nasal staphylococcal carriage rate among dermatology patients was significantly higher than that among neurosurgery patients (n = 25 (55.5%) vs. n = 42 (16.1%), p 0.005). This conclusion held when the carriage definition included individuals who were nasal culture positive on day 1 and day 3 of hospitalization (p 0.0001). All MRSA carriers were dermatology patients. There was significantly less S. aureus acquisition among non-carriers than among carriers during hospitalization (p 0.005). The mean number of days spent in the hospital before experiencing MRSA acquisition in nasal carriers was 5.1, which was significantly lower than the score among non-carriers (22 days, p 0.012). In conclusion, we found that nasal carriage of S. aureus predisposes to rather than protects against staphylococcal acquisition in the nose, thereby refuting our null hypothesis.

Prospective observational study of prior rectal colonization status as a predictor for subsequent development of Pseudomonas aeruginosa clinical infections.

The potential role of Pseudomonas aeruginosa (PA) intestinal colonization in the subsequent development of infections has not been thoroughly investigated. The aims of this study were to assess the role of PA intestinal colonization as a predictor of subsequent infections and to investigate the risk factors associated with the development of PA infection in patients in the intensive care unit (ICU). For this purpose, a prospective study was conducted that included (i) active surveillance of PA rectal colonization at ICU admission and weekly until ICU discharge, (ii) detection of PA clinical infections, and (iii) genotypic analysis by pulsed-field gel electrophoresis (PFGE). A total of 414 patients were included, of whom 179 (43%) were colonized with PA. Among the 77 patients who developed PA infection, 69 (90%) had prior PA colonization, and 60 (87%) of these showed genotyping concordance between rectal and clinical isolates. The probability of PA infection 14 days after ICU admission was 26% for carriers versus 5% for noncarriers (P < 0.001). Cox regression analysis identified prior PA rectal colonization as the main predictor of PA infection (hazard ratio [HR], 15.23; 95% confidence interval [CI], 6.9 to 33.7; P < 0.001). Prior use of nonantipseudomonal penicillins was also identified as an independent variable associated with PA infection (HR, 2.15; 95% CI, 1.3 to 3.55; P < 0.003). Our study demonstrated that prior PA rectal colonization is a key factor for developing PA infection.

Effect of mupirocin decolonization on subsequent methicillin-resistant Staphylococcus aureus infection in infants in neonatal intensive care units.

To evaluate whether topical mupirocin treatment can effectively decolonize methicillin-resistant Staphylococcus aureus (MRSA) carriage and reduce subsequent MRSA infection in neonates. During a 1-year period, the infants admitted to our neonatal intensive care units (NICUs)-1 and NICU-2 were included, and specimens from the nares and umbilicus were obtained within 24 hours, and specimen collection was repeated weekly for 2 weeks. Mupirocin was administered for 5 days to the infants with MRSA colonization in NICU-1 during the first half of the year and then switched to those in NICU-2 during the second half of the year. A total of 525 infants were recruited: 257 infants in the treatment group and 268 in the control group. MRSA colonization was detected in 130 infants (25%) during NICU stay, which is a similar rate in both groups. Twenty-two (4.2%) episodes of MRSA infection were identified. The rate of MRSA infection was significantly higher in infants with prior colonization than in those without (10.2% vs. 2.3%, P<0.001). Among the infants with prior colonization, the rate of MRSA infection in the treatment group was significantly lower than that in the control group (3.2% vs. 16%, P=0.014), and the rate in the treatment group was comparable to that in those without colonization (P=0.7804). Of the 15 infants with both clinical and colonizing isolates, indistinguishable strains between the paired isolates from the same infant by molecular methods were identified in 14 infants (93%). Administering mupirocin topical therapy to MRSA-colonized infants in NICUs might reduce subsequent MRSA infections during hospitalization in these infants. A large-scale study should be conducted.

Predictive value of prior colonization and antibiotic use for third-generation cephalosporin-resistant enterobacteriaceae bacteremia in patients with sepsis.

To prevent inappropriate empiric antibiotic treatment in patients with bacteremia caused by third-generation cephalosporin (3GC)-resistant Enterobacteriaceae (3GC-R EB), Dutch guidelines recommend β-lactam and aminoglycoside combination therapy or carbapenem monotherapy in patients with prior 3GC-R EB colonization and/or recent cephalosporin or fluoroquinolone usage. Positive predictive values (PPVs) of these determinants are unknown. We retrospectively studied patients with a clinical infection in whom blood cultures were obtained and empiric therapy with broad-spectrum β-lactams and/or aminoglycosides and/or fluoroquinolones was started. We determined the PPVs of prior colonization and antibiotic use for 3GC-R EB bacteremia, and the consequences of guideline adherence on appropriateness of empiric treatment. Of 9422 episodes, 773 (8.2%) were EB bacteremias and 64 (0.7%) were caused by 3GC-R EB. For bacteremia caused by 3GC-R EB, PPVs of prior colonization with 3GC-R EB (90-day window) and prior usage of cephalosporins or fluoroquinolones (30-day window) were 7.4% and 1.3%, respectively, and PPV was 1.8% for the presence of any of these predictors. Adherence to Dutch sepsis guideline recommendations was 27%. Of bacteremia episodes caused by 3GC-R and 3GC-sensitive EB, 56% and 94%, respectively, were initially treated with appropriate antibiotics. Full adherence to guideline recommendations would hardly augment proportions of appropriate therapy, but could considerably increase carbapenem use. In patients receiving empiric treatment for sepsis, prior colonization with 3GC-R EB and prior antibiotic use have low PPV for infections caused by 3GC-R EB. Strict guideline adherence would unnecessarily stimulate broad-spectrum antibiotic use.

Risk factors and outcome of infections with Klebsiella pneumoniae carbapenemase-producing K. pneumoniae in kidney transplant recipients.

Solid organ transplant recipients are especially susceptible to healthcare-associated infections with Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp-HAIs). The aim of the study was to evaluate risk factors and outcome of these infections in kidney transplant recipients. This was a retrospective cohort of kidney transplant (KTx) recipients between January 2009 and December 2013. Cases were defined as patients who developed KPC-Kp-HAI, confirmed by PCR for bla( KPC) gene after KTx during the study period. We analysed variables related to recipient; induction immunosuppressant therapy; delayed graft function; use of invasive devices; SOFA score on the first day of infection; type of therapy; time from positive culture to appropriate antimicrobial therapy; bacteraemia; and concomitant infection. Outcome measures were the occurrence of KPC-Kp-HAI and 30-day mortality after KPC-Kp-HAI. A total of 1,101 were submitted to KTx in the period, 21 patients were classified as infected with KPC-Kp. Another ten patients had KPC-Kp-HAI in the period and were transplanted before 2009. Of those 31 patients, 48.4 % showed evidence of prior colonization and 38.7 % had bacteraemia. The most common site of infection was the surgical wound. Risk factors for KPC-Kp-HAI were multi-organ transplantation and the use of a ureteral stent. Eight of the infected patients experienced recurrence of the infection. The 30-day mortality rate was 41.9 %. Survival was significantly lower among the patients with KPC-Kp-HAI (72 vs. 89.1 %; P = 0.002). The only risk factor independently associated with 30-day mortality was an elevated SOFA score on the first day of infection. In KTx recipients, the occurrence of KPC-Kp-HAI was related to invasive devices and type of transplant; these infections had a high rate of recurrence and reduced survival after KTx.

Amphotericin B deoxycholate nasal spray administered to hematopoietic stem cell recipients with prior fungal colonization of the upper airway passages is associated with low rates of invasive fungal infection.

Invasive fungal infections cause major problems during hematopoietic stem cell transplantation (HSCT). Fungal colonization of the upper airway passages occurs frequently, and may serve as a portal of entry for potentially life-threatening fungal infections, especially in immunocompromised patients. A clinical practice was instituted at Northwestern Memorial Hospital in Chicago in 2005, to administer amphotericin B deoxycholate nasal spray (ABNS) 0.5% to all HSCT recipients with fungal colonization of their nasal passages, in addition to standard oral antifungal prophylaxis. Among 1945 HSCT patients treated during the study period, 109 patients were identified with positive fungal surveillance cultures. Breakthrough fungal infections occurred in only 2 patients (2%), thus in this select group of HSCT recipients, ABNS administration is associated with a very low rate of breakthrough infection.

Prevalencia y factores asociados a la colonización de microorganismos multirresistentes en centros de larga estancia de Gran Canaria

IntroductionMultidrug resistant organisms (MDRO) are an important cause of nosocomial infections, with complicated clinical-therapeutic management and elevated morbidity-mortality, and an increase in healthcare costs. In long term care facilities (LTCFs) colonization/infection by MDRO among residents is increasing, and they may act as reservoirs and vehicles for the dissemination and production of outbreaks by resistant strains in acute hospitals. This study aimed at determining the prevalence of carriers of some common MDRO, and identifying factors associated with carrier state. Material and methodsA cross-sectional prevalence study was conducted on 235 residents in two LTCFs in the province of Las Palmas de Gran Canaria (Canary Islands, Spain) between October and November of 2012. The presence of MMR was investigated in nasal, pharyngeal and rectal swabs using selective media. Risk factors associated with carrier state were calculated using univariate and multivariate analysis. ResultsMore than one-third (36.2%) of residents were found to be carriers of ≥ 1 distinct MDROs. More than one-quarter (26.6%) were carriers of ESBL producing Enterobacteriaceae, and 10.2% were MRSA carriers. Factors found to be associated with colonization by any MDRO were: prior colonization or infection by MDRO, hospitalization in the past 3 months, recurrent infections of the urinary tract, and peripheral arterial disease. ConclusionsThe prevalence of MDRO in the LTCFs settings studied is greater than that found in the literature, and in particular ESBL producing Enterobacteriaceae. Due to the high prevalence of infection/colonization by MDRO, it is possible that residents of LTCFs could act as important reservoirs of MDRO, and facilitate their spread into the acute care setting.

Factors predicting the cause and prognosis of central line-associated bloodstream infections.

The increased use of indwelling catheters has led to an increased number of deaths due to central line-associated bloodstream infection (CLABSI). Improving CLABSI outcomes requires the identification of clinical characteristics affecting drug selection and factors associated with poor prognosis. The medical records of inpatients admitted to St. Marianna University School of Medicine between April 1, 2010 and March 31, 2013 were evaluated for the results of catheter tip cultures. The clinical characteristics of these cases and the characteristics of the pathogens involved were investigated to identify prognostic factors. Of the 1629 catheter cultures investigated, 183 were CLABSIs. Among them, 105 were caused by gram-positive bacteria, 43 by gram-negative bacteria, and 35 by fungi. Gram-negative CLABSIs were more common in cases with prior colonization by gram-negative bacteria and post-surgical cases. Fungal CLASBIs were more common in the cases with prior colonization by fungi, high-calorie infusion enforcement, broad-spectrum antibiotic treatment, and post-surgical cases. Death was significantly more likely in cases with findings of inflammation at the catheter insertion site and in those with abnormal body temperature, tachycardia, or abnormal white blood cell count. Thus, when treating CLABSI in post-surgical cases and in cases with prior colonization by gram-negative bacteria, therapy should include anti-pseudomonal agents. Considering the factors predicting poor prognostic identified in this study, clinicians must check the vital signs and catheter insertion site in patients with indwelling catheters.

Protection against Streptococcus pneumoniae lung infection after nasopharyngeal colonization requires both humoral and cellular immune responses.

Streptococcus pneumoniae is a common cause of pneumonia and infective exacerbations of chronic lung disease, yet there are few data on how adaptive immunity can specifically prevent S. pneumoniae lung infection. We have used a murine model of nasopharyngeal colonization by the serotype 19F S. pneumoniae strain EF3030 followed by lung infection to investigate whether colonization protects against subsequent lung infection and the mechanisms involved. EF3030 colonization induced systemic and local immunoglobulin G against a limited number of S. pneumoniae protein antigens rather than capsular polysaccharide. During lung infection, previously colonized mice had increased early cytokine responses and neutrophil recruitment and reduced bacterial colony-forming units in the lungs and bronchoalveolar lavage fluid compared with control mice. Colonization-induced protection was lost when experiments were repeated in B-cell- or neutrophil-deficient mice. Furthermore, the improved interleukin (IL)-17 response to infection in previously colonized mice was abolished by depletion of CD4+ cells, and prior colonization did not protect against lung infection in mice depleted of CD4+ cells or IL17. Together these data show that naturally acquired protective immunity to S. pneumoniae lung infection requires both humoral and cell-mediated immune responses, providing a template for the design of improved vaccines that can specifically prevent pneumonia or acute bronchitis.

Recurrence of group B streptococcus colonization in successive pregnancies.

To identify risk factors for group B streptococcus (GBS) colonization in a subsequent pregnancy using microbiological and clinical data from a prior pregnancy. A retrospective cohort study of women over a 10-year period, using laboratory records to identify women with GBS culture results available in two successive pregnancies. One thousand eight hundred and ninety-four women met eligibility criteria. Of these, 1293 were not GBS-colonized in either pregnancy, 198 were colonized in both pregnancies and 403 had discordant colonization status. GBS colonization in the index pregnancy was positively associated with multiparity, premature delivery and lower maternal age and negatively associated with chorioamnionitis. The strongest predictor of colonization in a subsequent pregnancy was colonization in the index pregnancy (50% likelihood if colonized compared with 14% if not in the index pregnancy, relative risk 3.6, confidence interval (CI)=3.1 to 4.3). GBS colonization in the subsequent pregnancy was independently associated with: GBS colonization in the index pregnancy (odds ratio (OR)=6.28; CI=4.91 to 8.05), preterm delivery in the index pregnancy (OR=1.80; CI=1.05 to 3.09) and prior early pregnancy loss (OR=1.15; CI=1.04 to 1.27). GBS colonization in a prior pregnancy is informative of colonization in a subsequent pregnancy. These data support providing antimicrobial prophylaxis in unscreened parous women with known prior GBS colonization.

Estudio epidemiológico de portadores nasofaríngeos de Streptococcus pneumoniae en niños en la comunidad autónoma de Murcia

Background and objectivesStreptococcus pneumoniae is a human pathogen that requires prior nasopharyngeal colonization to cause disease. An epidemiological study was conducted on nasopharyngeal carriers of pneumococci in healthy children in Murcia after the introduction of the VCN7, and immediately before the marketing of new vaccines, with the aim of determining the influence of vaccination in our geographic area, and other factors in relation to the state of being a carrier, and the different circulating serotypes. MethodsA multicentre study was conducted in in 60 primary care health centres in summer 2009 and winter of 2010. A nasopharyngeal swab was collected, and an epidemiological study was carried out on 1562 children aged 1 and 4 years. Of the 1562 nasopharyngeal samples, pneumococci were found in 489 of them, with 343 of them able to be serotyped (70.2%). ResultsThe prevalence of carriers was 31.3%. Of the patients included, 61.7% (964/1562) had received at least one dose of VCN7. Only 12.8% of the identified serotypes were vaccine serotypes. The independent protective factors against colonization were; Summer time in all age groups, previous vaccination in all the children (OR: 0.75; 95%CI: 0.56–0.93]; P=.01, and in 1-year-olds (OR: 0.6; 95%CI: 0.42–0.84; P=.002), and had taken antibiotics in the last month in the total cohort [OR: 0.69; 95%CI: 0.50–0.96). On the other hand, attendance at school or day-care centre (OR: 1.85; 95%CI: 1.27–2.18; P=.001), number of siblings (OR: 1.3; 95%CI: 1.01–1.91), and passive tobacco smoke exposure (OR: 1.33; 95%CI: 1.02–1.73), were colonization risk factors. The serotypes 6A, 19A, 23B, 15A/B, 11A, 14, 23A/F, 3 y 19F were the most prevalent. ConclusionsA low proportion of SV was found, with 14, 23F and 19F are persisting. A high prevalence of serotypes 6A and 19A was found. Summer time, vaccination, and the prior administration of antibiotics proved to be protective against colonization, whereas schooling, smoking, and siblings contributed to it.