Ten years with colistin: a retrospective case series.

OBJECTIVE: At the Shaare Zedek Medical Center, we have been using colistimethate sodium (CMS) for empiric as well as pathogen-directed treatment. We present our 10-year experience. METHODS: We conducted a retrospective case-series analysis of patients admitted from 1 January 2004 through 1 May 2014 who received at least one dose of CMS. Patient characteristics analysed for all admission for which patients received CMS, included: age, number of re-admissions, admission ward, renal function, disposition and microbiology results. Overall trend in defined daily dose (DDD) for CMS and resistant isolates was analysed. RESULTS: A total of 5603 admissions met inclusion criteria. Patients' mean (±SD) age was 80 ± 14 years, 1162 (48%) of the admissions were from a healthcare facility and 4367 (78%) of the admissions were to general Internal Medicine wards. The median number of hospital admissions per patient was 5, median admission and discharge creatinine (mg/dl) were 1.05 and 1.01, respectively; 2.3% of admissions required first-time dialysis. The discharge rate from the hospital was 58.4%. Excluding intrinsically CMS-resistant gram-negative organisms, bloodstream and urine isolates were 98% and 100% susceptible, respectively. CMS use (DDDs) increased during the study (p for trend = 0.04) without significant increase in incidence of multidrug-resistant organisms. CONCLUSIONS: Colistimethate sodium use at our institution has increased during this 10-year period. Nevertheless, there is no increasing trend in CMS-resistant organisms, 58% of the patients were discharged alive, and we did not observe significant nephrotoxicity in patients prescribed CMS. CMS should be reserved for microbiologically confirmed extensively drug-resistant gram-negative infections.

Independent risk factors for the co-colonization of vancomycin-resistant Enterococcus faecalis and methicillin-resistant Staphylococcus aureus in the region most endemic for vancomycin-resistant Staphylococcus aureus isolation.

In the majority of cases of vancomycin-resistant Staphylococcus aureus (VRSA), vancomycin-resistant Enterococcus faecalis (VR E. faecalis) served as the vanA donor to S. aureus. Previous studies that evaluated the risk factors for co-colonization with VRE and MRSA did not differentiate between VR E. faecalis and VR E. faecium. This study aimed to identify variables associated with VR E. faecalis and MRSA co-colonization. A retrospective case-control study from January 2008 to December 2009 was conducted at the Detroit Medical Center. Data were extracted from charts and pharmacy records. Unique patients co-colonized with VR E. faecalis and MRSA (defined as isolation of MRSA within 7 days of VR E. faecalis isolation) were compared with patients with VR E. faecalis who were not co-colonized with MRSA. A total of 546 patients with VR E. faecalis isolation were identified. 85 (15.6 %) VR E. faecalis patients were co-colonized with MRSA and 461 (84.4 %) VR E. faecalis patients were not co-colonized with MRSA. The mean age of the study cohort was 65.9 ± 16.4 years, 424 (77.7 %) were African-American, and 270 (49.5 %) were residing in long-term care institutions. Independent predictors of co-colonization of VR E. faecalis and MRSA were male gender, impaired consciousness, ICU stay prior to VR E. faecalis isolation, indwelling devices, and isolation of VR E. faecalis from wounds. MRSA was frequently isolated from the same culture specimen as VR E. faecalis (n = 39, 45.9 %), most commonly from wounds. This large study of patients with VR E. faecalis identified the severity of illness, indwelling devices, and chronic wounds as independent predictors of co-colonization with VR E. faecalis and MRSA.

The relationship between the new taxonomy of Streptococcus bovis and its clonality to colon cancer, endocarditis, and biliary disease.

BACKGROUND: The nomenclature of Streptococcus bovis has changed. The study aims were to examine and compare the clinical characteristics and outcomes of infections based on the new taxonomy and the genetic relatedness of strains. METHODS: Bacteremic cases from 2004 to 2010 at Assaf Harofeh Medical Center were reviewed. VITEK 2 later confirmed with polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) was used for subspecies identification. VITEK 2 later confirmed with Etests was used for minimal inhibitory concentration (MIC) testing. Repetitive extragenic palindromic polymerase chain reaction (rep-PCR) was used to determine the genetic relatedness of strains. RESULTS: Twenty-four bacteremia cases were included. The median age of patients was 81 years (range 1 day to 91 years), two were neonates, three were pregnant, and 18 were elderly (≥ 65 years of age). The Charlson's combined conditional age-related score was 8.2 ± 2.9, and 11 (58 %) patients were immunosuppressed. There were 13 patients who had S. gallolyticus subsp. pasteurianus, six had S. gallolyticus subsp. gallolyticus, four had S. infantarius subsp. coli, and one had S. infantarius subsp. infantarius. Ten of 19 non-pregnant adult patients had colon adenoma or carcinoma, three had acute biliary disease, and five had endocarditis. Two patients died in the hospital. rep-PCR revealed polyclonality. There were no significant associations between subspecies or genotypes and the various clinical characteristics or outcomes. CONCLUSION: S. bovis bacteremia is a serious disease that affects elderly immunosuppressed individuals. Infection is strongly associated with colon pathology and endocarditis, regardless of the new taxonomy or clone complex. The identification of S. bovis is of paramount importance, and microbiology laboratories should differentiate its processing from that of other S. viridans.

The impact of bedside wipes in multi-patient rooms: a prospective, crossover trial evaluating infections and survival.

BACKGROUND: Multidrug-resistant organisms (MDROs) are prevalent on high-touch surfaces in multi-patient rooms. AIM: To quantify the impact of hanging single-use cleaning/disinfecting wipes next to each bed. Pre-specified outcomes were: (1) hospital-acquired infections (HAIs), (2) cleaning frequency, (3) MDRO room contamination, (4) new MDRO acquisitions, and (5) mortality. METHODS: Clustered randomized crossover trial at Shamir Medical Center, Israel (October 2016 to January 2018). Clusters were randomly assigned to use for cleaning either single-use quaternary ammonium wipes (Clinell) or standard practices (reusable cloths and buckets with bleach). Six-month intervention periods were implemented in alternating sequence, separated by a washout period. Five high-touch surfaces were monitored by fluorescent markers. Study outcomes were compared between periods using generalized estimating equations, Poisson regression, and Cox proportional hazards models. FINDINGS: Overall, 7725 patients were included (47,670 person-days), 3793 patients in rooms with intervention cleaning and 3932 patients in rooms with standard practices. During the intervention, there was no significant difference in HAI rates (incidence rate ratio: 1.6; 95% confidence interval (CI): 0.7-3.5; P = 0.3). However, in intervention rooms, the frequency of environmental cleaning was higher (odds ratio: 3.73; 95% CI: 2.0-7.1; P < 0.0001), MDRO environmental contamination rate was insignificantly lower (odds ratio: 0.7; 95% CI: 0.5-1.0; P = 0.06), new MDRO acquisition rate was lower (hazard ratio: 0.4; 95% CI: 0.2-1.0; P = 0.04), and in-hospital mortality rate was lower (incidence rate ratio: 0.8; 95% CI: 0.7-1.0; P = 0.03). CONCLUSION: Hanging single-use cleaning/disinfecting wipes next to each bed did not affect the HAI rates but did improve the frequency of cleaning, reduce MDRO environmental contamination, and was associated with reduced incidence of new MDRO acquisitions and reduced mortality. This is a feasible, recommended practice to improve patient outcomes in multi-patient rooms.

How to: molecular investigation of a hospital outbreak.

BACKGROUND: Studying hospital outbreaks by using molecular tools, i.e. synthesizing the molecular epidemiology data to its appropriate clinical-epidemiologic context, is crucial in order to identify infection source, infer transmission dynamics, appropriately allocate prevention resources and implement control measures. Whole-genome sequencing (WGS) of pathogens has become the reference standard, as it is becoming more accessible and affordable. Consequently, sequencing of the full pathogen genome via WGS and major progress in fit-for-purpose genomic data analysis tools and interpretation is revolutionizing the field of outbreak investigations in hospitals. Metagenomics is an additional evolving field that might become commonly used in the future for outbreak investigations. Nevertheless, practitioners are frequently limited in terms of WGS or metagenomics, especially for local outbreak analyses, as a result of costs or logistical considerations, reduced or lack of locally available resources and/or expertise. As a result, traditional approaches, including pulsed-field gel electrophoresis, repetitive-element palindromic PCR and multilocus sequence typing, along with other typing methods, are still widely used. AIMS: To provide practitioners with evidenced-based action plans for usage of the various typing techniques in order to investigate the molecular epidemiology of nosocomial outbreaks, of clinically significant pathogens in acute-care hospitals. SOURCES: PubMed search with relevant keywords along with personal collection of relevant publications. CONTENT: Representative case scenarios and critical review of the relevant scientific literature. IMPLICATIONS: The review provides practical action plans to manage molecular epidemiologic investigations of outbreaks caused by clinically significant nosocomial pathogens, while prioritizing the use and timely integration of the various methodologies.

Epidemiology of bacteremia episodes in a single center: increase in Gram-negative isolates, antibiotics resistance, and patient age.

Increased resistance among isolates causing bacteremia constitutes a major challenge to medical practitioners and institutions. Variability between institutes is substantial, and requires the individual analysis of local trends. An eight-year (1997-2004) surveillance study of episodes of bacteremia was conducted in an 850-bed university hospital in central Israel. Trends of incidence, resistance, age, and mortality were analyzed. We studied 6,096 patient-unique episodes of bacteremia, of which, 2,722 (45.3%) were nosocomial and 523 (9.2%) involved children less than 18 years of age. The overall incidence of bacteremia episodes has increased over the study years by 39% and the patient mean age by 7.5 years. Gram-negative organisms accounted for 72% of hospital-acquired cases and 69% of community-acquired cases. There was a substantial increase in the incidence of nosocomial episodes, predominantly due to Gram-negative isolates, mainly Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli. Increased resistance to broad-spectrum antibiotics was noted among Gram-negative organisms, including quinolones (in K. pneumoniae), imipenem (A. baumannii and P. aeruginosa), piperacillin-tazobactam (K. pneumoniae), and amikacin (A. baumannii and P. aeruginosa). Increased resistance to oxacillin among coagulase-negative staphylococci was also noted. The all-cause mortality rates showed a significant rise. The patient age, intensive care unit (ICU) stay, and hospital acquisition were independently associated with mortality. We describe an increase in the incidence and resistance of Gram-negative organisms causing bacteremia and concomitant ageing of the patients with bacteremia. Similar patterns have been reported from other localities, and are of real concern.

Appropriate antimicrobial therapy in the era of multidrug-resistant human pathogens.

The past decade has brought a significant rise in antimicrobial resistance, and the ESKAPE pathogens have become a significant threat to public health. Three epidemiological features that negatively impact patients, which are consistently seen with the ESKAPE pathogens, are the following: 1) there has been a rise in incidence of these organisms as causative human pathogens, 2) there has been a significant increase in antimicrobial resistance in these bacterial species, and 3) the infections caused by these resistant strains are associated with worse outcomes when compared with infections caused by their susceptible counterparts. Significant delays in time to appropriate antimicrobial therapy of up to 5 days have been reported in infections due to these organisms and this is the strongest predictor of mortality with ESKAPE pathogens, particular in critically ill patients, where every hour delay has an incremental survival disadvantage for patients. Strategies to decrease these delays are urgently needed. Although routine broad-spectrum empiric coverage for these organisms would ideally limit this delay, agents with activity against these organisms are sometimes less effective, have significant toxicity risk, and their use can result in the development of resistance. Therefore, strategies to optimize therapy, although limiting unnecessary use of broad-spectrum antimicrobials, are urgently needed. This review will discuss potential strategies to optimize empiric therapy in the age of multi-drug resistance, the limitations of these strategies, and will discuss future directions and opportunities.

Case-control study to identify factors associated with mortality among patients with methicillin-resistant Staphylococcus aureus bacteraemia.

Methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia is associated with increased mortality. Delay in appropriate antimicrobial therapy (DAAT) is an important risk factor for death, although confounding between carriage of MRSA and DAAT has not been resolved. We studied the association of risk factors with mortality and searched for specific populations vulnerable to DAAT. We conducted a case-control study comparing patients with MRSA bacteraemia who died during hospitalization (cases) with patients with MRSA bacteraemia who survived (controls) in three medical centres in two states. Patients were identified using computerized hospital databases for the years 2001-2005. Medical records were retrieved and various epidemiological data extracted. Bivariate and multivariate logistic regression analyses were performed. Overall, 388 patients with MRSA bacteraemia were included, 164 cases and 224 controls. According to bivariate analyses, cases were significantly more likely than controls to (i) be older (>65 years), (ii) have transferred from an institution, (iii) have stayed in an ICU, (iv) have had more invasive devices, (v) have a poorer prognosis on admission, (vi) have higher disease severity at the time of bacteraemia, and (vii) have a DAAT of > or = 2 days. Upon multivariate analysis, among patients >65 years, DAAT was significantly associated with increased mortality (p 0.04). Furthermore, patients >65 years with severe sepsis were much more likely to experience DAAT (p 0.02). In elderly patients with MRSA bacteraemia, DAAT is associated with increased mortality. Moreover, advanced age is a predictor for DAAT. These significant epidemiological associations mandate early coverage of MRSA in septic elderly patients.

Clonal variability of group B Streptococcus among different groups of carriers in southern Israel.

A high prevalence of maternal group B Streptococcus (GBS) carriage and an extremely low incidence of invasive neonatal disease have been reported from southern Israel. In order to obtain insight into this discrepancy, this study was performed to determine the population structure of GBS from asymptomatic pregnant women living in this area. Seventy-two strains from maternal GBS carriers were characterized using multilocus sequence typing (MLST). Epidemiologic characteristics of the carriers and their newborns, including demographic variables, obstetric status, and general health parameters, were collected by means of a postpartum interview and a review of the relevant medical records. The MLST analysis grouped the bacteria into six different lineages (clonal complexes). Lineage ST-2 was prevalent among Bedouin-Arabs (p=0.01) and lineage ST-22 among Jews (p=0.001). Lineage ST-17 was prevalent among carriers who emigrated after 1997 from western nations of the former USSR (p<0.001). Lineage ST-22 was associated with carriage of surface-protein C (p=0.01) and lineage ST-17 with surface-protein R (p<0.01). Lineage ST-2 was prevalent among consumers of antibiotics (p=0.02) and was associated with erythromycin-resistant strains (p<0.001). Each subgroup of the southern Israeli maternal population has a different distribution of GBS clones. The clones prevalent among the Bedouin-Arabs and the Jews are known to be of low virulence. Lineage ST-17, which is associated with invasive disease, is prevalent among women who emigrated from western Soviet nations. Therefore, a different policy of GBS prophylaxis, resembling the one executed in endemic areas, should be considered in this population.