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Featured researches published by Samira Masarwa.


Infection Control and Hospital Epidemiology | 2011

Carbapenem-Resistant Klebsiella pneumoniae in Post-Acute-Care Facilities in Israel

Debby Ben-David; Samira Masarwa; Shiri Navon-Venezia; Hagit Mishali; Ilan Fridental; Bina Rubinovitch; Gill Smollan; Yehuda Carmeli; Mitchell J. Schwaber

OBJECTIVE To assess the prevalence of and risk factors for carbapenem-resistant Klebsiella pneumoniae (CRKP) carriage among patients in post-acute-care facilities (PACFs) in Israel. DESIGN, SETTING, AND PATIENTS A cross-sectional prevalence survey was conducted in 12 PACFs. Rectal swab samples were obtained from 1,144 patients in 39 [corrected] wards. Risk factors for CRKP carriage were assessed among the cohort. Next, a nested, matched case-control study was conducted to define individual risk factors for colonization. Finally, the cohort of patients with a history of CRKP carriage was characterized to determine risk factors for continuous carriage. RESULTS The prevalence of rectal carriage of CRKP among 1,004 patients without a history of CRKP carriage was 12.0%. Independent risk factors for CRKP carriage were prolonged length of stay (odds ratio [OR], 1.001; P < .001), sharing a room with a known carrier (OR, 3.09; P = .02), and increased prevalence of known carriers on the ward (OR, 1.02; P = .013). A policy of screening for carriage on admission was protective (OR, 0.41; P = .03). Risk factors identified in the nested case-control study were antibiotic exposure during the prior 3 months (OR, 1.66; P = .03) and colonization with other resistant pathogens (OR, 1.64; P = .03). Among 140 patients with a history of CRKP carriage, 47% were colonized. Independent risk factors for continued CRKP carriage were antibiotic exposure during the prior 3 months (OR, 3.05; P = .04), receipt of amoxicillin-clavulanate (OR, 4.18; P = .007), and screening within 90 days of the first culture growing CRKP (OR, 2.9; P = .012). CONCLUSIONS We found a large reservoir of CRKP in PACFs. Infection-control policies and antibiotic exposure were associated with patient colonization.


Journal of Antimicrobial Chemotherapy | 2015

Persistence of Klebsiella pneumoniae ST258 as the predominant clone of carbapenemase-producing Enterobacteriaceae in post-acute-care hospitals in Israel, 2008–13

Amos Adler; Omar Hussein; Debby Ben-David; Samira Masarwa; Shiri Navon-Venezia; Mitchell J. Schwaber; Yehuda Carmeli; Eric Setton; Shulamit Golan; Shai Brill; Valentina Lipkin; Evgeny Frodin; Gad Mendelson; Rachel Rave; Nava Yehuda; Ira Aizen; Michael Kaganski; Polina Gershkovich; Ady Sasson; Hana Yosef; Jochanan Stessman; Sofia Zlatkin; Ilana Or; Avraham Lazary; Irina Weinberg; Jack Madjar; Shoshi Taichman; Joshua Ben-Israel; Carola Vigder; Chaim Bar'el

OBJECTIVES To study the molecular characteristics of carbapenemase-producing Enterobacteriaceae (CPE) in post-acute-care hospitals (PACHs) in Israel and to analyse the temporal changes between 2008 and 2013. METHODS CPE isolates were obtained during two cross-sectional, point prevalence national surveys of PACHs in Israel performed in 2008 and 2013. Surveillance cultures were collected by streaking rectal swabs onto selective media. Isolates were identified to species level and tested for blaKPC, blaNDM and blaOXA-48 by PCR and by the Carba NP test. Molecular typing was done by PCR for the pilv-l gene, designed for the ST258 KPC-producing Klebsiella pneumoniae (KPC-KP) clone, BOX-PCR and MLST. RESULTS The prevalence of CPE carriage in the first survey was 184/1147 (16%); all of the isolates were KPC-KP. The prevalence of CPE carriage in the second survey was 127/1287 (9.9%); of these isolates, 113 (89%) were KPC-KP, 9 (7%) were other KPC-producing species and 5 (4%) were NDM- and OXA-48-producing CPE (n = 1 and 4, respectively). The proportion of the KPC-KP population represented by the ST258 clone increased from 120/184 (65%) in 2008 to 91/113 (80%) in 2013. In 58% (71/122) of the KPC-CPE carriers identified in the 2013 survey, the source of acquisition was determined to be the PACH itself. All four OXA-48 CPE were acquired either directly or indirectly from patients arriving from the Palestinian Authority or Syria. CONCLUSIONS Despite the decreased prevalence of CPE in Israeli PACHs, and the emergence of new types of CPE, the KPC-KP ST258 clone remains the predominant clone represented.


Infection Control and Hospital Epidemiology | 2014

A National Intervention to Prevent the Spread of Carbapenem- Resistant Enterobacteriaceae in Israeli Post-Acute Care Hospitals

Debby Ben-David; Samira Masarwa; Amos Adler; Hagit Mishali; Yehuda Carmeli; Mitchell J. Schwaber

OBJECTIVE Patients hospitalized in post-acute care hospitals (PACHs) constitute an important reservoir of antimicrobial-resistant bacteria. High carriage prevalence of carbapenem-resistant Enterobacteriaceae (CRE) has been observed among patients hospitalized in PACHs. The objective of the study is to describe the impact of a national infection control intervention on the prevalence of CRE in PACHs. DESIGN A prospective cohort interventional study. SETTING Thirteen PACHs in Israel. INTERVENTION A multifaceted intervention was initiated between 2008 and 2011 as part of a national program involving all Israeli healthcare facilities. The intervention has included (1) periodic on-site assessments of infection control policies and resources, using a score comprised of 16 elements; (2) assessment of risk factors for CRE colonization; (3) development of national guidelines for CRE control in PACHs involving active surveillance and contact isolation of carriers; and (4) 3 cross-sectional surveys of rectal carriage of CRE that were conducted in representative wards. RESULTS The infection control score increased from 6.8 to 14.0 (P < .001) over the course of the study period. A total of 3,516 patients were screened in the 3 surveys. Prevalence of carriage among those not known to be carriers decreased from 12.1% to 7.9% (P = .008). Overall carrier prevalence decreased from 16.8% to 12.5% (P = .013). Availability of alcohol-based hand rub, appropriate use of gloves, and a policy of CRE surveillance at admission to the hospital were independently associated with lower new carrier prevalence. CONCLUSION A nationwide infection control intervention was associated with enhanced infection control measures and a reduction in the prevalence of CRE in PACHs.


Veterinary Microbiology | 2013

Clonal transmission of a rare methicillin-resistant Staphylococcus aureus genotype between horses and staff at a veterinary teaching hospital.

Mitchell J. Schwaber; Shiri Navon-Venezia; Samira Masarwa; Sharon Tirosh-Levy; Amos Adler; Inna Chmelnitsky; Yehuda Carmeli; Eyal Klement; Amir Steinman

Methicillin-resistant Staphylococcus aureus (MRSA) infection or colonization has become a serious emerging condition in equine hospitals. Following the detection of MRSA in asymptomatic hospitalized horses and in two horses with post-operative wound infections, an investigation was conducted. Twelve of 84 horses (14.3%) and 16 of 139 personnel (11.5%) were MRSA carriers. The profile of the dominant MRSA strain common to horses and staff was multi-drug-resistant, spa-type t535, SCCmec type V, pvl-negative. MLST of a representative isolate yielded sequence type (ST) 5. The risk of MRSA carriage among veterinary personnel was greater in equine veterinarians and full-time technicians in comparison to part-time technicians and to other personnel not working with horses. Strict infection control measures were implemented, horses infected or colonized with MRSA were isolated and decolonization of personnel was attempted. Six months after the intervention, the large animal department personnel and hospitalized horses were all MRSA-negative and the decolonization was considered successful. This outbreak, caused by a rare MRSA strain and involving both hospitalized horses and personnel, further demonstrates the ability of MRSA to spread between animals and humans and emphasizes the importance of infection control measures to decrease the risk for MRSA colonization and infection of both horses and personnel.


Journal of Clinical Microbiology | 2013

Epidemiological and Microbiological Characteristics of an Outbreak Caused by OXA-48-Producing Enterobacteriaceae in a Neonatal Intensive Care Unit in Jerusalem, Israel

Amos Adler; Ester Solter; Samira Masarwa; Tamar Miller-Roll; Bassam Abu-Libdeh; Hatem Khammash; Khalil Najem; Susan Dekadek; Chen Stein-Zamir; Nafez Nubani; Amin Kunbar; Marc Victor Assous; Yehuda Carmeli; Mitchell J. Schwaber

ABSTRACT This study describes the course of an OXA-48-producing Enterobacteriaceae (OPE) outbreak that started in March 2012 in a neonatal intensive care unit (NICU) in Jerusalem, Israel. During the peak of the outbreak (January to August 2012), there were 49 patients who had proven or suspected acquisition of OPE in the NICU, including 16 with invasive infections, out of a total of 156 patients who were hospitalized during that period. Three children hospitalized in the pediatric ICU were identified as carriers of OPE. Three patients with a previous stay in the affected NICU were identified as OPE carriers upon admission to another hospital. The Ministry of Health was notified and then intervened in July 2012. Intervention included cohorting colonized patients, conducting frequent rectal-culture surveillance, and improving the implementation of infection control practices. As a result, the incidence of OPE acquisition declined to 5 cases in the first 4 months, followed by no new cases in the next 3 months. Thirty-one patient-unique isolates were available for analysis: 29 Klebsiella pneumoniae isolates, all belonging to a single clone (sequence type 39 [ST39]), and 2 isolates from Enterobacter cloacae. All isolates possessed the bla OXA-48 and bla CTX-M-14 genes, which are located on the same plasmid. This plasmid, similar to the global bla OXA-48-harboring vector, has now acquired bla CTX-M-14, leading to resistance to all β-lactam agents.


Clinical Infectious Diseases | 2011

High Prevalence of Methicillin-Resistant Staphylococcus aureus Among Residents and Staff of Long-term Care Facilities, Involving Joint and Parallel Evolution

Mitchell J. Schwaber; Samira Masarwa; Shiri Navon-Venezia; Yael Kandlik; Inna Chmelnitsky; Gill Smollan; Rivka Glick; Gila Neria; Yehuda Carmeli

Six long-term care facilities were surveyed for methicillin-resistant Staphylcoccus aureus (MRSA). Among 191 residents, 14% were carriers; 1 strain predominated (ST5-SCCmec II). Among 132 staff members, 11% were positive; 2 strains predominated (ST5-SCCmec II, ST8-SCCmec IV). All strains were Panton-Valentine leukocidin-negative. The epidemiology of MRSA among residents and staff involved joint and parallel evolution.


Journal of Clinical Microbiology | 2015

Methicillin-Resistant Staphylococcus aureus spa type t002 Outbreak in Horses and Staff at a Veterinary Teaching Hospital after its Presumed Introduction by a Veterinarian

Amir Steinman; Samira Masarwa; Sharon Tirosh-Levy; Dan Gleser; G. Kelmer; Amos Adler; Yehuda Carmeli; Mitchell J. Schwaber

ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) infection and colonization, involving MRSA strains which differ from common human health care-associated clones, have become serious emerging conditions in equine veterinary hospitals. In 2010, MRSA spa type t535 caused an outbreak involving both horses and personnel in a veterinary teaching hospital in Israel. Since then, surveillance continued, and occasional MRSA isolation occurred. Two years later, MRSA of another spa type, t002, was isolated from a veterinarian and, 3 weeks later, from a horse. The appearance of spa type t002, a common clone in human medicine in Israel, among both personnel and horses, prompted a point-prevalence survey of hospital personnel and hospitalized horses. Fifty-nine staff members (n = 16 equine; n = 43, other) and 14 horses were screened. Ten of 59 staff members (16.9%) and 7 of 14 horses (50%) were MRSA carriers. Among the staff, 44% of large animal department (LAD) personnel, compared with only 7% of non-LAD personnel, were carriers. Isolates from all horses and from 9 of 10 personnel were found to be of MRSA spa type t002. This clone was later isolated from an infected postoperative wound in a hospitalized horse. Measures were taken to contain transmission between horses and personnel, as was done in the previous outbreak, resulting in reduction of transmission and, finally, cessation of cross-transmission between horses and personnel.


Emerging Infectious Diseases | 2014

Persistence and complex evolution of fluoroquinolone-resistant Streptococcus pneumoniae clone.

Debby Ben-David; Mitchell J. Schwaber; Amos Adler; Samira Masarwa; Rotem Edgar; Shiri Navon-Venezia; David A. Schwartz; Nurith Porat; Tali Kotlovsky; Nikolay Polivkin; Irina Weinberg; Avraham Lazary; Nissim Ohana; Ron Dagan

This clone has persisted in a post–acute care facility for >5 years.


Journal of Clinical Microbiology | 2012

Prevalence of Streptococcus pneumoniae in Respiratory Samples from Patients with Tracheostomy in a Long-Term-Care Facility

Amos Adler; Debby Ben-David; Mitchell J. Schwaber; Samira Masarwa; David A. Schwartz; Nurith Porat; Tali Kotlovsky; Maya Shklyar; Nikolay Polivkin; Irina Weinberg; Avraham Lazary; Nissim Ohana; Ron Dagan

ABSTRACT We aimed to study the prevalence of Streptococcus pneumoniae in respiratory samples from institutionalized patients with chronic tracheostomy. A total of 264 pairs of nasopharyngeal and endotracheal cultures were collected. There was no difference in the proportion of positive cultures between children (21%) and adults (18%). However, the proportion of positive endotracheal cultures was higher than that of nasopharyngeal cultures in adults (18% versus 3%, respectively; P < 0.001) but not in children (17% in both sites).


Infection Control and Hospital Epidemiology | 2018

Israeli National Policy for Carbapenem-Resistant Enterobacteriaceae Screening, Carrier Isolation and Discontinuation of Isolation

Ester Solter; Amos Adler; Bina Rubinovitch; Elizabeth Temkin; David A. Schwartz; Debby Ben-David; Samira Masarwa; Yehuda Carmeli; Mitchell J. Schwaber

Since 2006, Israel has been confronting an outbreak of carbapenem-resistant Enterobacteriaceae (CRE), and in 2007 Israel implemented a national strategy to contain spread. The intervention was initially directed toward acute-care hospitals and later expanded to include an established reservoir of carriage in long-term-care hospitals. It included regular reporting of CRE cases to a central registry and daily oversight of management of the outbreak at the institutional level. Microbiological methodologies were standardized in clinical laboratories nationwide. Uniform requirements for carrier screening and isolation were established, and a protocol for discontinuation of carrier status was formulated. In response to the evolving epidemiology of CRE in Israel and the continued need for uniform guidelines for carrier detection and isolation, the Ministry of Health in 2016 issued a regulatory circular updating the requirements for CRE screening, laboratory diagnosis, molecular characterization, and carrier isolation, as well as reporting and discontinuation of isolation in healthcare institutions nationwide. The principal elements of the circular are contained herein. Infect Control Hosp Epidemiol 2018;39:85-89.

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Debby Ben-David

Israel Ministry of Health

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Ester Solter

Israel Ministry of Health

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David A. Schwartz

University of Colorado Denver

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Amir Steinman

Hebrew University of Jerusalem

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