Marc Victor Assous

Duration of carriage of carbapenem-resistant Enterobacteriaceae following hospital discharge

BACKGROUND Hospitalized carriers of carbapenem-resistant Enterobacteriaceae (CRE) are cohorted under contact precautions, including in the days between rehospitalization and surveillance culture results. This study investigates duration of CRE carriage to define populations requiring precautions upon readmission. METHODS Patients with CRE-positive culture during 2009-2010 were followed up by rectal swab cultures taken retrospectively and prospectively for the study or as part of clinical follow-up. RESULTS One hundred thirty-seven patients met the inclusion criteria, with follow-up cultures obtained from 97. Mean time to CRE negativity was 387 days (95% confidence interval: 312-463). Seventy-eight percent of patients (64/82) had positive culture at 3 months, 65% (38/58) at 6 months, and 39% (12/30) at 1 year. Duration of carriage was affected by repeat hospitalization (P = .001) and clinical, as opposed to surveillance, culture (P = .002). CONCLUSION CRE carriers from a previous hospitalization have a lower probability of CRE carriage upon readmission if the index specimen was a surveillance culture and 1 year passed without further hospitalization. Multiple hospitalizations and CRE disease extend duration of carriage. This study better defines patients requiring cohorting and isolation, thus limiting spread of CRE and allowing for improved allocation of infection control measures.

Worldwide emergence of colistin resistance in Klebsiella pneumoniae from healthy humans and patients in Lao PDR, Thailand, Israel, Nigeria and France owing to inactivation of the PhoP/PhoQ regulator mgrB: an epidemiological and molecular study

The emergence of colistin-resistant Klebsiella pneumoniae (CRKP) is a major public health concern worldwide. In this study, the prevalence and molecular basis of colistin resistance in CRKP isolated from healthy individuals and patients in Lao PDR, Thailand, Nigeria and France were investigated. Stool samples were screened by culture for the presence of colistin-resistant Klebsiella spp. Whole-genome sequence analysis was used to decipher the molecular mechanism of colistin resistance in a blaNDM-1-positive in vitro-selected CRKP mutant. PCR amplification and sequencing of the mgrB genetic environment was performed for all CRKP isolates as well as control colistin-susceptible K. pneumoniae (CSKP) isolates recovered from the same stools. A total of 869 stool samples were screened for colistin-resistant Klebsiella spp., yielding 32 CRKP and 2 colistin-resistant Klebsiella oxytoca. Comparative whole-genome sequence analysis revealed that an in vitro-selected CRKP mutant had an insertion sequence in its mgrB gene, as well as missense mutations in other selected clones. Of the 34 colistin-resistant Klebsiella spp. isolates, 14 (41.2%; 13 CRKP and 1 K. oxytoca) from the four countries also had various defects in their mgrB genes, but no such defects were found in the CSKP controls (P<10(-4)). Few mutations were observed in pmrAB compared with mgrB among the CRKP isolates. The worldwide emergence of CRKP is a major public health concern. Detection and surveillance of such strains are warranted to prevent an uncontrollable pandemic. Inactivation of the PhoP/PhoQ regulator gene mgrB is associated with ≥40% of colistin resistance among the CRKP isolates observed in this study.

Mortality due to blaKPC Klebsiella pneumoniae bacteraemia

OBJECTIVES To determine the mortality rate secondary to blaKPC Klebsiella pneumoniae (KPC/Kp) bacteraemia, compared with that from ESBL-producing K. pneumoniae (ESBL/Kp) bacteraemia, and to determine associated risk factors. METHODS This was a retrospective case-control study of all 68 KPC/Kp bacteraemia patients diagnosed since 2006, matched by year of isolation, gender and age, at a ratio of 1:2, to 136 ESBL/Kp bacteraemia patients. RESULTS There were no demographic differences between the two groups, but there were minor clinical differences. Fewer KPC/Kp study patients than ESBL/Kp control patients had a systolic blood pressure <90 mmHg (32/68, 47% versus 86/136, 63%, respectively, P = 0.02) or urinary catheterization (32/68, 47% versus 90/136, 66%, respectively, P = 0.005), while the KPC/Kp bacteraemia group had a greater incidence of acute renal failure (45/68, 66% versus 67/136, 49%, respectively, P = 0.02). There was no difference between the two groups in duration of hospitalization. The mortality rate of the KPC/Kp bacteraemia group was 44/68 (65%) compared with 54/136 (40%) in the ESBL/Kp bacteraemia control group (P = 0.008), which in the multivariate analysis remained highly significant (P < 0.001). Only 11/68 (16%) of KPC/Kp patients were functionally independent at discharge compared with 43/136 (32%) ESBL/Kp patients (P = 0.012). CONCLUSIONS The selection of an ESBL/Kp control cohort with a ratio of 1:2 (study versus control group) helped resolve an as yet insufficiently settled question: bacteraemia with KPC/Kp is an independent risk factor for death, justifying the strict adherence to cohorting and isolation procedures.

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

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.

Neutrophil Gelatinase-Associated Lipocalin as a Predictor of Complications and Mortality in Patients Undergoing Non-Cardiac Major Surgery

Introduction: We tested the hypothesis that urinary and serum neutrophil gelatinase-associated lipocalins (NGAL) early after non-cardiac major surgery predict postoperative acute kidney injury (AKI), complications and mortality. Methods: We studied 74 patients undergoing orthopedic, vascular and abdominal surgery lasting ≧2 h. NGAL was measured in preoperative, as well as 2- and 6-hour postoperative samples. The primary outcome was AKI. Secondary outcome was postoperative infection and death. Results: 10 patients (13.5%) developed AKI, 19 (26%) reached secondary outcomes, of whom 5 (7%) died. Serum NGAL was significantly higher in patients with diabetes and chronic kidney disease (CKD). No significant correlation was detected between serum or urine NGAL and subsequent development of AKI. Urine NGAL at 6 h and serum NGAL at 2 and 6 h were strongly correlated with postoperative infection and death (p = 0.004, p = 0.013 and p = 0.001, respectively). Conclusions: Our data suggest that in the general surgical population, NGAL could serve as a potent early biomarker for postoperative infection, and that the presence of CKD and diabetes mellitus is associated with higher levels of NGAL and may influence its predictive value.

Emergence of VIM-producing Aeromonas caviae in Israeli hospitals

OBJECTIVES Resistance to carbapenems in Aeromonas species is rare and mediated mostly by the chromosomal cphA gene. Our aims were to describe the molecular characteristics of the first cases of VIM-producing Aeromonas caviae isolated from human samples. METHODS Carbapenem-resistant Aeromonas (CRA) spp. were isolated from rectal surveillance cultures. Bacterial identification was done by dnaJ sequencing. Detection of metallo-carbapenemase and other β-lactamase genes was done by PCR. Molecular typing was done by PFGE. The genetic environment of the blaVIM gene was determined by sequencing. RESULTS Five CRA were isolated from surveillance cultures in 2010-13; four were from Shaare Zedek Medical Center and one was from Laniado Hospital. All five isolates were identified as A. caviae and comprised four different pulsotypes. MICs ranged from 0.5 to 8 mg/L for imipenem and from 0.25 to 8 mg/L for meropenem. All isolates were resistant to gentamicin, susceptible to amikacin and ciprofloxacin (except one), and were positive for carbapenemase production in the modified Hodge and Carba NP tests. The carbapenemase genes blaVIM-1 and blaVIM-35 were located inside a class I integron with two different sizes to its variable region. CONCLUSIONS This is the first report of blaVIM in A. caviae from human samples and the first report of VIM-producing Gram-negative bacteria in Israel. This finding is alarming as this species may spread via water or sewage systems. Although infection due to Aeromonas spp. is rare, the presence of the gene on a mobile element is of concern due to the potential for dissemination to clinically important Gram-negative pathogens.

Genomic Plasticity of Multidrug-Resistant NDM-1 Positive Clinical Isolate of Providencia rettgeri

We performed a detailed whole-genome sequence analysis of Providencia rettgeri H1736, a multidrug-resistant clinical pathogen isolated in Israel in 2011. The objective was to describe the genomic flexibility of this bacterium that has greatly contributed to its pathogenicity. The genome has a chromosome size of 4,609,352 bp with 40.22% GC content. Five plasmids were predicted, as well as other mobile genetic elements (MGEs) including phages, genomic islands, and integrative and conjugative elements. The resistome consisted of a total of 27 different antibiotic resistance genes including blaNDM-1, mostly located on MGEs. Phenotypically, the bacteria displayed resistance to a total of ten different antimicrobial classes. Various features such as metabolic operons (including a novel carbapenem biosynthesis operon) and virulence genes were also borne on the MGEs, making P. rettgeri H1736 significantly different from other P. rettgeri isolates. A large quantity of the genetic diversity that exists in P. rettgeri H1736 was due to extensive horizontal gene transfer events, leading to an enormous presence of MGEs in its genome. Most of these changes contributed toward the pathogenic evolution of this bacterium.We performed a detailed whole-genome sequence analysis of Providencia rettgeri H1736, a multidrug-resistant clinical pathogen isolated in Israel in 2011. The objective was to describe the genomic flexibility of this bacterium that has greatly contributed to its pathogenicity. The genome has a chromosome size of 4,609,352 bp with 40.22% GC content. Five plasmids were predicted, as well as other mobile genetic elements (MGEs) including phages, genomic islands, and integrative and conjugative elements. The resistome consisted of a total of 27 different antibiotic resistance genes including blaNDM-1, mostly located on MGEs. Phenotypically, the bacteria displayed resistance to a total of ten different antimicrobial classes. Various features such as metabolic operons (including a novel carbapenem biosynthesis operon) and virulence genes were also borne on the MGEs, making P. rettgeri H1736 significantly different from other P. rettgeri isolates. A large quantity of the genetic diversity that exists in P. rettgeri H1736 was due to extensive horizontal gene transfer events, leading to an enormous presence of MGEs in its genome. Most of these changes contributed toward the pathogenic evolution of this bacterium.

Low Interferon Relative-Response to Cytomegalovirus Is Associated with Low Likelihood of Intrauterine Transmission of the Virus

Background Congenital Cytomegalovirus (CMV) is a very common intrauterine infection which can cause severe mental and hearing impairments. Notably, only 40% of primarily infected women transmit CMV to the fetus. CMV-specific T-cell response has a role in CMV disease but individual immune heterogeneity precludes reliable correlation between measurable T-cells response and intrauterine transmission. Study Aim To establish a correlation between maternal T-cells response and fetal CMV transmission using an individual normalized immune response. Methods We analyzed IFN-γ secretion upon whole blood stimulation from primary CMV-infected pregnant women, with either CMV-peptides or PHA-mitogen. Results We established a new normalization method of individual IFN-γ response to CMV by defining the ratio between specific-CMV response and non-specific mitogen response (defined as IFN-γ relative response, RR), aiming to overcome high person-to-person immune variability. We found a unique subpopulation of women with low IFN-γ RR strongly correlated with absence of transmission. IFN-γ RR lower than 1.8% (threshold determined by ROC analysis) reduces the pre-test probability of transmission from 40% to 8%, revealing an unexpected link between low IFN-γ RR and non-transmission. Conclusion In pregnant women with primary CMV infection, low IFN-γ RR is associated with low risk of transmission.

Genome analysis of NDM-1 producing Morganella morganii clinical isolate

Objective: To analyze the resistome and virulence genes of Morganella morganii F675, a multidrug-resistant clinical isolate using whole genome sequencing (WGS). Methods: M. morganii F675 was isolated from a patient from Jerusalem, Israel. WGS was performed using both 454 and SOLiD sequencing technologies. Analyses of the bacterial resistome and other virulence genes were performed in addition to comparison with other available M. morganii genomes. Results: The assembled sequence had a genome size of 4,127,528 bp with G+C content of 51%. The resistome consisted of 13 antibiotic resistance genes including blaNDM-1 located in a plasmid likely acquired from Acinetobacter spp. Moreover, we characterized for the first time the whole lipid A biosynthesis pathway in this species along with the O-antigen gene cluster, the urease gene cluster and several other virulence genes. Conclusion: The WGS analysis of this pathogen further provides insight into its pathogenicity and resistance to antibiotics.

Improving implementation of infection control guidelines to reduce nosocomial infection rates: pioneering the report card.

BACKGROUND Two detailed checklists were developed, based on published infection control guidelines, for daily use by infection control practitioners in departments and operating rooms. AIM To assess the impact of the checklists on nosocomial infection rates in three hospitals over the course of one year. METHODS The checklists included 20 subheadings (± 150 items). Project nurses conducted rounds in the study (but not control) departments; during each round, the nurses selected 15-20 items for observation, marked the checklists according to appropriateness of observed behaviour and provided on-the-spot corrective education. Rates of adherence to the checklist, antibiotic use, number of obtained and positive cultures, and positive staff hand and patient environment cultures were reported monthly as a report card to relevant personnel and administrators. The rate of nosocomial infections was determined in the first and last months. RESULTS The baseline nosocomial infection rate was similar in the study and control departments: 37/345 (11%) and 26/270 (10%) respectively. In the last month, the rate in the study department decreased to 16/383 (4%) (P<0.01); in the control it decreased insignificantly to 21/248 (8%) (not significant). No significant trends were detected in the number of obtained cultures, positive cultures, or antibiotic use. Adherence to guidelines ranged from 75% to 94% between the hospitals (P<0.001): the overall rate increased from 80% to 91% (P<0.01). CONCLUSIONS The use of checklists during the conduct of infection control rounds, combined with monthly reports, was associated with a significant decrease in nosocomial infections in study departments.