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1.
Eur J Clin Microbiol Infect Dis ; 33(11): 1909-13, 2014 Nov.
Article in English | MEDLINE | ID: mdl-24865248

ABSTRACT

The optimal method for surveillance of carbapenem-resistant Acinetobacter spp. (CRAB) is unknown. A collection of CRAB strains (n = 42), carbapenem-susceptible strains (CSAB), and non-Acinetobacter strains (n = 18) was used to evaluate six laboratory surveillance methods: MacConkey (MAC), MAC + 1 µg/ml imipenem (MAC-IPM), minimal salts agar + 1 % acetate (MSA), MSA with IPM disk (MSA-IPM), CHROMagarKPC, and CHROMagar Acinetobacter with CR102 (CHROMAcineto). CHROMAcineto was 100 % sensitive and specific. CHROMagarKPC and MAC-IPM were highly sensitive (>95 %), but their specificity was substantially hampered by the breakthrough growth of CSAB. MSA was unsuitable for CRAB detection. CHROMAcineto is a promising medium for CRAB detection and warrants further clinical evaluation.


Subject(s)
Acinetobacter Infections/diagnosis , Acinetobacter/isolation & purification , Anti-Bacterial Agents/pharmacology , Bacteriological Techniques/methods , Carbapenems/pharmacology , Culture Media/chemistry , beta-Lactam Resistance , Agar , Humans , Sensitivity and Specificity
2.
Eur J Clin Microbiol Infect Dis ; 33(3): 325-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24030718

ABSTRACT

Methicillin-resistant Staphylococcus aureus (MRSA) mediastinitis after median sternotomy is a major complication of cardiac surgery with significant morbidity and mortality rates. We evaluated the efficacy of ceftobiprole medocaril in a new rat model of mediastinitis and compared it to vancomycin. The model was induced in 92 rats. Infection was induced immediately after median sternotomy by the injection of MRSA (strain 3020, 1 × 10(7) cfu/rat) into the sternal bone. After 24 h, rats (groups of 6-8) were treated intraperitoneally for 5 days or 14 days by either: (i) saline (control, q8h), (ii) ceftobiprole medocaril (70 or 100 mg/kg, q8h), or (iii) vancomycin (50 mg/kg, q12h). Efficacy was determined by a reduction in bacterial cfu in the sternum and spleen tissues. Comparisons were performed using the Mann-Whitney test. A 5-day treatment course of ceftobiprole at both doses tested lead to a significant reduction in MRSA load in the sternum (p < 0.01) as compared to the control group and compared to 5-day vancomycin treatment, which lead to a non-significant reduction (p = 0.07). Longer treatment (14 days) with ceftobiprole lead to a complete clearance of MRSA from the sternum, similarly to vancomycin. Ceftobiprole also showed a significant effect on eliminating MRSA dissemination to the spleen compared to saline-treated rats. Ceftobiprole was effective in treating MRSA mediastinitis in the rat model. In the 5-day course, ceftobiprole showed a significant reduction in sternal MRSA counts and was superior to vancomycin. After 14 days, both ceftobiprole and vancomycin showed clearance of MRSA from the sternum in more than 50 % of rats and almost complete clearance in the remainder.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Cephalosporins/therapeutic use , Mediastinitis/drug therapy , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Staphylococcal Infections/drug therapy , Animals , Disease Models, Animal , Male , Mediastinitis/microbiology , Rats , Staphylococcal Infections/microbiology , Sternum/microbiology
3.
J Hosp Infect ; 83(4): 344-6, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23419597

ABSTRACT

We report a nosocomial outbreak of urinary tract infection by extremely drug resistant Pseudomonas aeruginosa, susceptible only to colistin. Infection in three patients followed urodynamic studies. Two of the three patients were children, one of whom also developed urosepsis. The investigation led to detection of contaminated pressure transducers. Genotyping confirmed that patient and transducer isolates were identical. These transducers were not labelled as 'single use only' despite the possibility that contaminated urine may reflux and mix with the fluid in the device. The issue of re-usable versus single-use urodynamic devices is discussed.


Subject(s)
Cross Infection/epidemiology , Disease Outbreaks , Drug Resistance, Multiple, Bacterial , Equipment and Supplies/microbiology , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa/drug effects , Urinary Tract Infections/epidemiology , Aged , Child , Cross Infection/microbiology , Genotype , Humans , Male , Molecular Typing , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/classification , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/isolation & purification , Urinary Tract Infections/microbiology
4.
Antimicrob Agents Chemother ; 57(3): 1474-9, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23295937

ABSTRACT

It is more convenient and practical to collect rectal swabs than stool specimens to study carriage of colon pathogens. In this study, we examined the ability to use rectal swabs rather than stool specimens to quantify Klebsiella pneumoniae carbapenemase (KPC)-producing carbapenem-resistant Enterobacteriaceae (CRE). We used a quantitative real-time PCR (qPCR) assay to determine the concentration of the bla(KPC) gene relative to the concentration of 16S rRNA genes and a quantitative culture-based method to quantify CRE relative to total aerobic bacteria. Our results demonstrated that rectal swabs are suitable for quantifying the concentration of KPC-producing CRE and that qPCR showed higher correlation between rectal swabs and stool specimens than the culture-based method.


Subject(s)
Bacterial Proteins/genetics , Colon/microbiology , Klebsiella Infections/microbiology , Klebsiella pneumoniae/isolation & purification , RNA, Ribosomal, 16S/genetics , beta-Lactamases/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/isolation & purification , Bacterial Typing Techniques , Carbapenems/pharmacology , Feces/microbiology , Humans , Klebsiella Infections/diagnosis , Klebsiella Infections/drug therapy , Klebsiella pneumoniae/drug effects , Klebsiella pneumoniae/genetics , Real-Time Polymerase Chain Reaction , Specimen Handling , beta-Lactam Resistance/drug effects , beta-Lactamases/isolation & purification
5.
Clin Microbiol Infect ; 19(4): E190-6, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23331385

ABSTRACT

The natural history of KPC-producing Klebsiella pneumoniae (KPC KP) carriage is unknown. We aimed to examine the duration of KPC KP carriage following hospital discharge and to study the risk factors for persistent carriage. A cohort of 125 KPC KP carriers was followed monthly for between 3 and 6 months after discharge from an acute-care hospital. Rectal swabs and data were collected at baseline and at each visit. KPC KP was detected by culture and direct blaKPC PCR. Acquisition time was regarded as the earliest date of KPC KP isolation. Resolution of carriage was defined as a negative KPC KP test in at least two consecutive samples. Analyses were separated for recent (<4 months) (REC, 75 patients) and remote (≥4 months) (REM, 50 patients) acquisition groups. Risk factors for persistent carriage were examined by survival analyses for the REC group and by prevalence methods for the REM group. The mean age of patients was 67.5 years and 49.6% were male. Forty-six (61%) patients in the REC group and 14 (28%) in the REM group were persistent carriers (p < 0.001). A significant risk factor for persistent carriage identified in both the REC and REM groups was the presence of any catheter (p < 0.05). Unique risk factor groups included long-term care facility (LTCF) residence (p < 0.01) and a low functional status as measured by the Barthel's index (p < 0.05) in the REC group and high Charlson's score in the REM group (p < 0.05). Out of the entire 100 patients who had at least one negative sample, only 65 remained negative on subsequent cultures. In conclusion, persistent carriage of KPC KP is associated with catheter use and a low functional status; it is more common in patients with recent acquisition and is related to LTCF stay. A single negative KPC KP test is insufficient to exclude persistent carriage.


Subject(s)
Carrier State/epidemiology , Gastrointestinal Tract/microbiology , Klebsiella Infections/epidemiology , Klebsiella pneumoniae/enzymology , beta-Lactamases/metabolism , Adult , Aged , Aged, 80 and over , Carrier State/microbiology , Cohort Studies , Female , Follow-Up Studies , Hospitals , Humans , Klebsiella Infections/microbiology , Klebsiella pneumoniae/isolation & purification , Male , Middle Aged , Patient Discharge , Prospective Studies , Risk Factors , Time Factors
6.
Clin Microbiol Infect ; 19(5): 451-6, 2013 May.
Article in English | MEDLINE | ID: mdl-22563800

ABSTRACT

Carbapenem-resistant Enterobacteriaceae (CRE) are emerging extremely drug-resistant pathogens; blaKPC is the predominant carbapenemase in Israel. Early detection of asymptomatic rectal carriers is important for infection control purposes. We aimed to determine who among newly identified CRE rectal carriers is prone to have a subsequent clinical specimen with CRE. A matched case-control study was conducted in a tertiary care teaching hospital in Israel. Cases with a primary positive CRE rectal test and subsequent CRE clinical specimens were matched in a 1:2 ratio with CRE rectal carriers who did not develop subsequent CRE clinical specimens (controls). Matching was based on calendar time of primary CRE isolation, whether the primary CRE isolation was ≤ 48 h or > 48 h after hospital admission, and time at risk to have a subsequent clinical specimen. Data were extracted from the patients' medical records and from the hospital's computerized database. One hundred and thirty-two newly identified CRE rectal carriers (44 cases, 88 controls) were included. The median time interval between screening and subsequent clinical specimens was 11 days (range, 3-27); 86% of the clinical specimens were classified as true infections. Independent predictors of subsequent CRE clinical specimens were: admission to the intensive care unit, having a central venous catheter, receipt of antibiotics, and diabetes mellitus. Identification of the risk factors for subsequent infections among CRE-colonized patients can be used to control modifiable risk factors and to direct empirical antimicrobial therapy when necessary.


Subject(s)
Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Enterobacteriaceae Infections/microbiology , Enterobacteriaceae/enzymology , Rectum/microbiology , beta-Lactam Resistance , beta-Lactamases/metabolism , Adult , Aged , Aged, 80 and over , Carrier State/epidemiology , Carrier State/microbiology , Case-Control Studies , Enterobacteriaceae/isolation & purification , Enterobacteriaceae Infections/epidemiology , Female , Humans , Israel/epidemiology , Male , Middle Aged , Risk Factors
7.
J Antimicrob Chemother ; 68(1): 74-83, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23042812

ABSTRACT

OBJECTIVES: A KPC-producing Klebsiella pneumoniae clone, sequence type (ST) 258, has emerged and spread worldwide. This study aimed to identify putative genes that may contribute to the extraordinary dissemination of the KPC-producing ST258 clone. METHODS: A suppressive subtractive hybridization (SSH) library was constructed using two KPC-producing strains: an epidemic ST258 and a non-epidemic ST376. The fragments obtained were sequenced, analysed and their presence among 27 additional ST258 isolates and 21 isolates of non-epidemic STs was determined. The functions of the putative proteins were extracted from NCBI databases. Localization to plasmid/chromosome was determined by PCR after transformation and by Southern hybridization. In silico homologues for the subtractive fragments were searched among sequences available in the NCBI database. RESULTS: SSH yielded 42 fragments (50 proteins) specific to the ST258 isolate tested, 30 of them located on various plasmids. The ST258 strains examined could be divided into two groups, one in which all 50 genes were ubiquitous and another group that lost 11 fragments, all located on one of the plasmids. This group of 50 genes was absent among other STs tested. Nineteen genes were unique to ST258 strains and 17 to CC258 (where CC stands for clonal complex). Most of the deduced proteins belonged to two major functional groups: 15 to the cell motility and secretion group, and 14 to the DNA repair and modification group. CONCLUSIONS: This study identifies unique genes in ST258 bacteria that may contribute to its epidemiological success as compared with other KPC-producing STs. Conservation of plasmid-encoded genes among ST258 isolates, despite plasmid variation, supports their importance in the success of this clone.


Subject(s)
Bacterial Proteins/genetics , Drug Resistance, Multiple, Bacterial/genetics , Epidemics , Klebsiella pneumoniae/genetics , beta-Lactamases/genetics , Bacterial Proteins/isolation & purification , Cloning, Molecular , Humans , Klebsiella Infections/epidemiology , Klebsiella Infections/genetics , Klebsiella pneumoniae/isolation & purification , Prospective Studies , beta-Lactamases/isolation & purification
8.
Eur J Clin Microbiol Infect Dis ; 32(4): 513-21, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23117265

ABSTRACT

Community-onset bloodstream infections caused by extended-spectrum ß-lactamase-producing Escherichia coli (ESBL-EC-COBSIs) were investigated over a 7-year-period (2003-2009) in our institution. ESBL-EC-COBSI inclusion criteria were cefotaxime/ceftazidime non-susceptible blood isolates recovered during 48 h upon hospital admission. Forty-one isolates were molecularly characterized. Susceptibilities were determined (Vitek-2) and genotyping was performed [multilocus sequence typing (MLST)]. CTX-M genes were determined [polymerase chain reaction (PCR) and sequencing] and bla CTX-M-encoding plasmids (n = 10) were analyzed and compared. Phylogrouping and virulence genes were identified (PCR). The incidence rate of ESBL-EC-COBSIs has increased from 2.94 to 7.87 cases/10,000 admissions. All isolates were multidrug-resistant (MDR), displaying co-resistance to ciprofloxacin (93 %), trimethoprim-sulfamethoxazole (85 %), and gentamicin (51 %). MLST identified ten sequence types (STs), of which five were novel. ST131 accounted for 66 % of the cases (27/41), and dominated over the years (prevalence of 25 % in 2003 and 85 % in 2009). All isolates carried CTX-M genes with the following prevalence: bla CTX-M-2 (6/8; 75 %) in 2003; bla CTX-M-15 (9/13, 69 % in 2007); and bla CTX-M-15 (11/20, 55 %) and bla CTX-M-14 (7/20, 35 %) in 2009. bla CTX-M-15- and bla CTX-M-14-encoding plasmids harbored by ST131 differed. Of all isolates, 98 % belonged to virulent phylogroups B2 (28/41, 68 %) and D (12/41, 29 %), though ST131 isolates carried a higher number of virulence genes compared to other lineages (p < 0.05). The incidence of ESBL-EC-COBSIs increased 2.7-fold during the period 2003-2009. This increase appears to be related to the emergence and clonal expansion of bla CTX-M-15- or bla CTX-M-14-carrying ST131. The superiority of this virulent lineage should be further explored.


Subject(s)
Bacteremia/epidemiology , Community-Acquired Infections/epidemiology , Escherichia coli Infections/epidemiology , Escherichia coli/classification , Escherichia coli/enzymology , beta-Lactamases/metabolism , Anti-Bacterial Agents/pharmacology , Bacteremia/microbiology , Community-Acquired Infections/microbiology , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Escherichia coli/genetics , Escherichia coli/isolation & purification , Escherichia coli Infections/microbiology , Humans , Incidence , Israel/epidemiology , Microbial Sensitivity Tests , Molecular Epidemiology , Molecular Sequence Data , Multilocus Sequence Typing , Polymerase Chain Reaction , Prevalence , Retrospective Studies , beta-Lactams/pharmacology
9.
J Clin Microbiol ; 51(1): 177-81, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23115260

ABSTRACT

In the last decade, the global emergence of carbapenem resistance in Enterobacteriaceae has posed great concern to public health. Data concerning the role of environmental contamination in the dissemination of carbapenem-resistant Enterobacteriaceae (CRE) are currently lacking. Here, we aimed to examine the extent of CRE contamination in various sites in the immediate surroundings of CRE carriers and to assess the effects of sampling time and cleaning regimens on the recovery rate. We evaluated the performance of two sampling methods, CHROMAgar KPC contact plate and eSwab, for the detection of environmental CRE. eSwab was followed either by direct plating or by broth enrichment. First, 14 sites in the close vicinity of the carrier were evaluated for environmental contamination, and 5, which were found to be contaminated, were further studied. The environmental contamination decreased with distance from the patient; the bed area was the most contaminated site. Additionally, we found that the sampling time and the cleaning regimen were critical factors affecting the prevalence of environmental CRE contamination. We found that the CHROMAgar KPC contact plate method was a more effective technique for detecting environmental CRE than were eSwab-based methods. In summary, our study demonstrated that the vicinity of patients colonized with CRE is often contaminated by these organisms. Using selective contact plates to detect environmental contamination may guide cleaning efficacy and assist with outbreak investigation in an effort to limit the spread of CRE.


Subject(s)
Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Enterobacteriaceae/drug effects , Enterobacteriaceae/isolation & purification , Environmental Microbiology , beta-Lactam Resistance , Bacterial Shedding , Bacteriological Techniques/methods , Enterobacteriaceae Infections/microbiology , Humans , Time Factors
10.
J Hosp Infect ; 81(1): 15-9, 2012 May.
Article in English | MEDLINE | ID: mdl-22463977

ABSTRACT

BACKGROUND: Over the last decade, extremely-drug-resistant (XDR) strains of Klebsiella pneumoniae have emerged worldwide, mainly as a result of patient-to-patient spread. The predominant clone, sequence type 258 (ST258), is associated with high morbidity and mortality, and is a worldwide threat to public health. It was hypothesized that reduced susceptibility to chlorhexidine, the most widely used hospital disinfectant, may contribute to the endemic nature of this strain. AIM: To characterize and compare the susceptibility of the epidemic K. pneumoniae clone ST258 and non-epidemic K. pneumoniae clones to chlorhexidine. METHODS: The minimum inhibitory concentration (MIC) of chlorhexidine was determined in 126 XDR K. pneumoniae clinical isolates using agar dilution. Expression of three different efflux pumps -cepA, acrA and kdeA - was investigated in the absence and presence of chlorhexidine using quantitative real-time polymerase chain reaction. Heteroresistance to chlorhexidine was identified using population analysis. FINDINGS: The MIC of chlorhexidine was higher for K. pneumoniae ST258 (N = 70) than other K. pneumoniae sequence types (N = 56); 99% of ST258 isolates had MICs >32 µg/mL, compared with 52% of other K. pneumoniae sequence types (P < 0.0001). Reduced susceptibility to chlorhexidine appeared to be independent of the expression of cepA, acrA and kdeA efflux pumps. Chlorhexidine-resistant subpopulations were observed independent of the bacterial sequence type or the MIC. CONCLUSIONS: Reduced susceptibility to chlorhexidine may contribute to the success of XDR K. pneumoniae as a nosocomial pathogen, and may provide a selective advantage to the international epidemic strain K. pneumoniae ST258. The heterogeneous nature of chlorhexidine-resistant subpopulations suggests that this phenomenon might not be rendered genetically.


Subject(s)
Chlorhexidine/pharmacology , Disinfectants/pharmacology , Drug Resistance, Multiple, Bacterial , Klebsiella pneumoniae/drug effects , Bacterial Proteins/biosynthesis , Bacterial Proteins/genetics , Cross Infection/microbiology , Gene Expression Profiling , Humans , Klebsiella Infections/microbiology , Klebsiella pneumoniae/isolation & purification , Microbial Sensitivity Tests/methods , Real-Time Polymerase Chain Reaction
11.
J Clin Microbiol ; 50(1): 134-7, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22031705

ABSTRACT

From 2006 to 2009, 315 clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates were collected from 5 hospitals across Israel. Most isolates (64%) were related to the global clones spa types t001-SCCmec-I (SCCmec-I stands for staphylococcal cassette chromosome mec type I) (n = 99; 31%), t002-SCCmec-II (n = 82; 26%), and t008-SCCmec-IV (n = 21; 7%), five of which were identified as MRSA strain USA-300. Seventeen strains unique to Israel were identified. SCCmec types IV and V were common among hospital-acquired isolates.


Subject(s)
Methicillin-Resistant Staphylococcus aureus/classification , Methicillin-Resistant Staphylococcus aureus/genetics , Molecular Typing , Staphylococcal Infections/epidemiology , Staphylococcal Infections/microbiology , Cluster Analysis , DNA, Bacterial/genetics , Genotype , Humans , Israel/epidemiology , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Molecular Epidemiology
12.
Eur J Clin Microbiol Infect Dis ; 31(7): 1429-33, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22068274

ABSTRACT

Microbiological surveillance for detection of carbapenem-resistant A. baumannii is important, but recovery of A. baumannii is inadequate. We studied A. baumannii recovery by a particular transport system that is possibly superior over standard swabs, using reference and clinical strains. First, the recovery rates relating to the various swabs were compared with regard to various combinations of transport times (0 h, 1 h, 24 h, 48 h), storage times (0 weeks, 1 week, 2 weeks, 4 weeks) and storage temperatures (4°c,-80°c) using live counts. Second, the recovery of different inocula of strains mixed with fecal microbiota was evaluated by plating on selective medium. The new transport system exhibited a decline of <3log10 under almost all conditions studied and performed better than standard swabs under several conditions. If plated on selective media, the new transport system performed well, even after prolonged transport or with a low inoculum, and its processing could be delayed by up to 2 weeks, especially if refrigerated. The new transport system may thus enhance A. baumannii surveillance.


Subject(s)
Acinetobacter Infections/microbiology , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/isolation & purification , Bacteriological Techniques/methods , Carbapenems/pharmacology , Specimen Handling/methods , beta-Lactam Resistance , Anti-Bacterial Agents/pharmacology , Humans
13.
Clin Microbiol Infect ; 17(1): 52-6, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20219078

ABSTRACT

In 2008, an increase in the prevalence of carbapenem-resistant Klebsiella pneumoniae was noted in a 286-bed tertiary case hospital in Colombia, where 84 patients (32 infected and 52 colonized) had positive cultures. The identified index patient came from Israel for a liver transplantation. High level carbapenem resistance was observed. Polymyxin B and tigecycline were the only two antibiotics that remained active. PCR-restriction fragment length polymorphism analysis and sequencing revealed blaKPC-3 in the major clone, which was indistinguishable from the K. pneumoniae carbapenemase-3-producing clone described previously in Israel. This exemplifies the threat posed by the global spread of K. pneumoniae carbapenemase-producing pathogens.


Subject(s)
Bacterial Proteins/metabolism , Cross Infection/microbiology , Cross Infection/transmission , Klebsiella Infections/microbiology , Klebsiella Infections/transmission , beta-Lactamases/metabolism , Anti-Bacterial Agents/therapeutic use , Colombia , Cross Infection/drug therapy , Cross Infection/mortality , Humans , Israel , Klebsiella Infections/drug therapy , Klebsiella Infections/mortality , Klebsiella pneumoniae/classification , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/isolation & purification , Molecular Typing
14.
Epidemiol Infect ; 138(2): 244-52, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19602299

ABSTRACT

We aimed to study patterns of shigellosis in a large observant Jewish community in Israel and to describe local interventions during outbreaks. Surveillance data from the Ministry of Health were used to calculate incidence rates in 1998-2006, both in the city of Bene Beraq and the Tel Aviv district. Information on isolates was collected from the bacteriological laboratory of a community hospital. Public notices and educational conferences conveyed a message to increase personal hygiene and keep ill children at home. During a 9-year period, a clear biennial pattern of outbreaks was noticed. Annual incidence rates ranged between 18 and 353/100,000 population. Shigellosis outbreaks tended to occur in the winter and were attributed to clonally related Shigella sonnei strains. Outbreaks in Bene Beraq preceded those in the other cities of Tel Aviv district, suggesting propagation of disease. In this population with highly endemic as well as superimposed outbreaks of shigellosis, short-term interventions had no lasting effect on prevention; future studies should focus on community-based programmes to avoid anticipated outbreaks.


Subject(s)
Disease Outbreaks/statistics & numerical data , Dysentery, Bacillary/epidemiology , Shigella sonnei/isolation & purification , Adolescent , Adult , Aged, 80 and over , Child , Child, Preschool , Community-Acquired Infections/epidemiology , Electrophoresis, Gel, Pulsed-Field , Female , Humans , Incidence , Infant , Israel/epidemiology , Judaism , Male , Seasons , Shigella sonnei/genetics
15.
Antimicrob Agents Chemother ; 52(9): 3029-34, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18573929

ABSTRACT

Extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae strains are suggested to possess higher pathogenic potential than non-ESBL producers. Microbial adherence to and invasion of host cells are critical steps in the infection process, so we examined the expression of type 1 and 3 fimbrial adhesins by 58 ESBL-producing and 152 nonproducing isolates of K. pneumoniae and their abilities to invade ileocecal and bladder epithelial cells. Mannose-sensitive hemagglutination of guinea pig erythrocytes and mannose-resistant hemagglutination of ox erythrocytes were evaluated to determine the strains' abilities to express type 1 and type 3 fimbriae, respectively. Bacterial adhesion to and invasion of epithelial cells were tested by enzyme-linked immunosorbent assay and imipenem killing assay, respectively. The adherence of ESBL- and non-ESBL-producing strains to epithelial cells did not differ significantly (P > 0.05). In contrast, the proportion of strains capable of invading (>5% relative invasion) ileocecal and bladder epithelial cells was significantly higher among ESBL producers (81%, n = 47/58, and 27.6%, n = 16/58, respectively) than among non-ESBL producers (61%, n = 93/152, and 10%, n = 15/152, respectively) (P = 0.0084, odds ratio [OR] = 2.711, 95% confidence interval [CI] = 1.302 to 5.643 and P = 0.0021, OR = 4.79, 95% CI = 1.587 to 7.627). The mean invasion by ESBL producers (5.5% +/- 2.8% and 3.3% +/- 2.7%, respectively) was significantly higher than that by non-ESBL producers (2.9% +/- 2.6% and 1.8% +/- 2%, respectively) (P < 0.0001). Likewise, the proportion of ESBL producers coexpressing both fimbrial adhesins was significantly higher (79.3%; n = 46/58) than that of non-ESBL producers (61.8%; n = 94/152) (P = 0.0214; OR = 2,365; 95% CI = 1.157 to 4.834). Upon acquisition of SHV-12-encoding plasmids, two transconjugants switched on to produce type 3 fimbriae while expression of type 1 fimbriae was not affected. The acquisition of an ESBL plasmid appeared to upregulate the phenotypic expression of one or more genes, resulting in greater invasion ability.


Subject(s)
Adhesins, Bacterial/metabolism , Bacterial Adhesion , Epithelial Cells/microbiology , Gene Expression Regulation, Bacterial , Klebsiella pneumoniae/pathogenicity , beta-Lactamases/biosynthesis , Adhesins, Bacterial/genetics , Animals , Cecum/cytology , Cell Line , Conjugation, Genetic , Erythrocytes/microbiology , Erythrocytes/physiology , Guinea Pigs , Hemagglutination , Humans , Ileum/cytology , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/metabolism , Microbial Sensitivity Tests , Urinary Bladder/cytology , beta-Lactamases/genetics
16.
Eur J Clin Microbiol Infect Dis ; 27(5): 385-90, 2008 May.
Article in English | MEDLINE | ID: mdl-18074160

ABSTRACT

Molecular characterization of methicillin-resistant Staphylococcus aureus isolates from three hospitals in Israel was the aim of the study presented here. We identified 11 distinct genetic clones by pulsed-field gel electrophoresis. Molecular typing identified four different SCCmec types-I, II, IV, and V-and nine spa types. Spa type t002 was the most common.


Subject(s)
Bacterial Typing Techniques , Methicillin Resistance , Staphylococcal Infections/epidemiology , Staphylococcal Infections/microbiology , Staphylococcus aureus/classification , Staphylococcus aureus/genetics , DNA Fingerprinting/methods , DNA, Bacterial/genetics , Electrophoresis, Gel, Pulsed-Field , Genotype , Hospitals , Humans , Israel/epidemiology , Molecular Epidemiology , Staphylococcus aureus/drug effects , Staphylococcus aureus/isolation & purification
17.
Eur J Clin Microbiol Infect Dis ; 26(11): 793-800, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17701063

ABSTRACT

We conducted a retrospective matched cohort study to examine the impact of isolation of multi-drug-resistant (MDR) Acinetobacter baumannii on patient outcomes. Cases from whom MDR A. baumannii was isolated in a clinical culture (n = 118) were compared with controls from whom MDR A. baumannii was not isolated (n = 118). Cases and controls were matched according to ward, calendar month of hospitalization, and duration of hospitalization before culture. The following outcomes were compared in multivariable analysis: in-hospital mortality, length of stay, need for mechanical ventilation, and functional status at discharge. MDR A. baumannii was determined to be a pathogen in 72% of cases. In 36% of cases, the patient died, versus 21% of controls (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.17-4.16, P = 0.014). Median length of stay for surviving cases was 17 days, versus 11 for surviving controls (multiplicative effect 1.55, 95% CI 0.99-2.44, P = 0.057). Fifty-two percent of cases required mechanical ventilation, versus 25% of controls (OR 3.72, 95% CI 1.91-7.25, P<0.001); 60% of surviving cases were discharged with reduced functional status, versus 38% of controls (OR 4.4, 95% CI 1.66-11.61, P = 0.003). In multivariable analysis, clinical isolation of MDR A. baumannii remained a significant predictor of mortality (OR 6.23, 95% CI 1.31-29.5, P = 0.021), need for mechanical ventilation (OR 7.34, 95% CI 2.24-24.0, P<0.001), and reduced functional status on discharge (OR 7.93, 95% CI 1.1-56.85, P = 0.039). Thus, MDR A. baumannii acquisition is associated with severe adverse outcomes, including increased mortality, need for mechanical ventilation, and reduced functional status.


Subject(s)
Acinetobacter Infections/microbiology , Acinetobacter baumannii/drug effects , Drug Resistance, Multiple, Bacterial , Acinetobacter Infections/drug therapy , Acinetobacter Infections/mortality , Acinetobacter baumannii/isolation & purification , Aged , Case-Control Studies , Consciousness , Female , Humans , Length of Stay , Male , Multivariate Analysis , Prognosis , Respiration, Artificial , Retrospective Studies , Treatment Outcome
18.
Eur J Clin Microbiol Infect Dis ; 26(3): 189-94, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17265070

ABSTRACT

Routine susceptibility testing of 5,616 Shigella isolates at the National Shigella Reference Centre in Israel over a 5-year period (2000-2004) revealed resistance to ceftriaxone in one strain of Shigella boydii 2 and in two strains each of Shigella flexneri 2a, S. flexneri 6, and Shigella sonnei. All seven isolates were confirmed as producers of extended-spectrum beta-lactamase (ESBL) by the combination disk method, the Vitek 1 system, and a modification of the double-disk synergy test, which is based on the inhibitory properties of clavulanic acid, tazobactam, and sulbactam. Tazobactam had the strongest effect in all seven strains. Molecular characterization of the ESBLs identified CTX-M-type enzymes, consisting of the CTX-M-9 group (n = 3), CTX-M-3 (n = 2), CTX-M-39 (n = 1), and CTX-M-2 group (n = 1). Three of the strains also carried bla-(OXA) genes and a bla-(TEM) gene. Although the prevalence of ESBLs in this study was low, further research is needed on the spread and transfer of resistance genes, both in hospitals and in the community.


Subject(s)
Dysentery, Bacillary/microbiology , Shigella/drug effects , Shigella/enzymology , beta-Lactamases/biosynthesis , Adolescent , Anti-Bacterial Agents/pharmacology , Cefuroxime/pharmacology , Child , Child, Preschool , Drug Resistance, Multiple, Bacterial , Humans , Infant , Israel , Microbial Sensitivity Tests , Polymerase Chain Reaction/methods , Shigella/isolation & purification , beta-Lactamases/metabolism
19.
Eur J Clin Microbiol Infect Dis ; 25(11): 719-22, 2006 Nov.
Article in English | MEDLINE | ID: mdl-17043835

ABSTRACT

The aims of the study presented here were to determine the prevalence of Staphylococcus aureus carriage and, specifically, community-acquired methicillin-resistant S. aureus (CA-MRSA) carriage in children and their parents in Israel and to determine the genetic relatedness of these isolates. S. aureus was isolated from 580 of 3,373 (17.2%) individuals screened. The predominant type identified by pulsed-field gel electrophoresis was strain ST45-MSSA (25%). Five MRSA isolates were detected, and two of these were classified as CA-MRSA, based on the following criteria: no previous contact with a healthcare facility, absence of a multidrug-resistant (MDR) phenotype, and presence of SCCmec type IV. Isolates were negative for pvl and were classified as ST-45-MRSA. Although CA-MRSA is still rare in Israel, the genetic relatedness of the strains found in this study to a successful MSSA clone warrants close follow up.


Subject(s)
Community-Acquired Infections/epidemiology , Community-Acquired Infections/microbiology , Methicillin Resistance , Staphylococcus aureus/classification , Staphylococcus aureus/drug effects , Adolescent , Adult , Carrier State/epidemiology , Carrier State/microbiology , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Israel/epidemiology , Male , Middle Aged , Prevalence , Staphylococcal Infections/epidemiology , Staphylococcal Infections/microbiology , Staphylococcus aureus/genetics
20.
Clin Infect Dis ; 42(7): 925-34, 2006 Apr 01.
Article in English | MEDLINE | ID: mdl-16511754

ABSTRACT

BACKGROUND: The prevalence of infections caused by extended-spectrum beta -lactamase (ESBL)-producing Enterobacteriaceae is increasing worldwide. The influx of these bacteria into hospitals has major implications for infection-control and empirical treatment strategies. METHODS: Isolates from 2 patient cohorts--patients with gram-negative bacteremia within 2 days after admission and patients screened for fecal colonization at admission--were assessed for ESBL production. ESBL phenotype was confirmed according to Clinical and Laboratory Standards Institute guidelines. Predictors of ESBL phenotype were examined by univariate and multivariate analyses. RESULTS: Of 80 Enterobacteriaceae isolates from blood samples obtained at admission to the hospital, 13.7% produced ESBL. Thirty-eight patients with ESBL-positive isolates and 72 with ESBL-negative isolates were included in a case-control study. Predictors of ESBL production were male sex and nursing home residence (area under receiver operator characteristic curve, 0.7). Of 241 persons screened at admission, 26 (10.8%) had fecal carriage of ESBL-producing Enterobacteriaceae. Predictors of fecal carriage were poor functional status, antibiotic use, chronic renal insufficiency, liver disease, and use of histamine2 blockers (area under receiver operator characteristic curve, 0.8). Four (15.4%) of the 26 individuals with fecal carriage had subsequent bacteremia with ceftazidime-resistant Enterobacteriaceae, compared with 1 (0.5%) noncarrier (odds ratio, 38.9; P<.001). Of 80 ESBL-producing Enterobacteriaceae isolates obtained at admission, 65 were health care associated, and 15 were community acquired. The 15 community-acquired ESBL-producing Enterobacteriaceae belonged to diverse clones. The most prevalent ESBL gene among these isolates was CTX-M-2 (found in 53.3% of the isolates). CONCLUSIONS: We report high rates of bacteremia and colonization with ESBL-producing Enterobacteriaceae at admission to our institution, which may undermine infection-control measures and complicate the selection of empirical treatment.


Subject(s)
Bacteremia/microbiology , Cross Infection/microbiology , Enterobacteriaceae/isolation & purification , beta-Lactamases/biosynthesis , Aged , Aged, 80 and over , Case-Control Studies , Electrophoresis, Gel, Pulsed-Field , Enterobacteriaceae/drug effects , Enterobacteriaceae/enzymology , Feces/microbiology , Female , Humans , Male , Microbial Sensitivity Tests , Multivariate Analysis
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