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INTRODUCCIÓN: La restricción programada (RP) de antimicrobianos puede disminuir selectivamente la tasa de infecciones por determinados microorganismos. En este sentido, los bacilos gramnegativos productores de beta-lactamasas AmpC (BGN-blaAmpC) son seleccionados por el sobreuso de cefalosporinas de tercera generación (C3G). Estas bacterias, también adquieren genes y co-producen otras beta-lactamasas, como las de Nueva Delhi (BGN-blaNDM). OBJETIVOS: Disminuir la tasa de aislamiento de BGN-blaAmpC y BGN-blaNDM en cultivos de pacientes de la UCI luego de una RP de C3G en el marco de un brote nosocomial por estos microrganismos. MATERIALES Y MÉTODOS: Estudio cuasi-experimental, previo (P1= 12 meses) y posterior (P2= 12 meses) a una RP de C3G en un hospital de adultos, donde, en el contexto de brote mencionado, se aplicaron medidas de control de infecciones generales. El uso de antimicrobianos se expresó como "porcentaje de los días de tratamiento (%DDT)"/100 camas ocupadas al día (100-COD). Se compararon las tasas de aislamiento de BGN-blaAmpC y BGN-blaNDM en hemocultivos (HC), mini-lavados bronquio-alveolares (mB) y urocultivos (UC) en la UCI. RESULTADOS: En P2 el consumo de C3G fue 2,5% DDT/100-COD. Hubo un descenso en los aislamientos de BGN-blaAmpC en HC (RR 0,48 [0,2-0,9] p < 0,02) y mB (RR 0,52 [0,3-0,9] p < 0,02), así como también de BGN-blaNDM en HC (RR 8,1 [1,6-39,4] p < 0,00). Conclusiones: La RP de C3G se asoció con la reducción de los BGN-blaAmpC y BGN-blaNDM en HC, así como de los BGN-blaAmpC mB.
BACKGROUND: Programmed restriction (PR) of antimicrobials can selectively decrease the rate of infections by certain microorganisms. In this sense, AmpC beta-lactamase-producing gram-negative bacilli (GNB-blaAmpC) are selected for the overuse of third generation cephalosporins (3GC). These bacteria also acquire genes and co-produce other β-lactamases, such as New Delhi ones (GNB-blaNDM). AIM: To decrease the isolation rate of GNB- blaAmpC and GNB- blaNDM in cultures from ICU patients after a PR of 3GC. METHODS: Quasi-experimental study, before (P1= 12 months) and after (P2= 12 months) a PR of 3GC in an adults' hospital. The use of antibiotics was expressed as "percentage days of treatment (%DOT)" /100 beds occupied per day (100-BOD). The rates of GNB-blaAmpC and GNB-blaNDM were compared in blood cultures (BC), mini-bronchio alveolar lavages (mB) and urine cultures (UC) in the ICU. RESULTS: In P2, 3GC consumption was 2.5% DOT/100-COD. There was a decrease in GNB-blaAmpC from BC (RR 0.48 [0.2-0.9] p < 0.02) and mB (RR 0.52 [0.3-0.9] p < 0.02), as well as of GNB-blaNDM from BC (RR 8.1 [1.6-39.4] p < 0.00). Conclusions: PR of 3GC was linked to the reduction of GNB-blaAmpC and GNB-blaNDM in BC, as well as GNB-blaAmpC in mB from ICU patients.
Subject(s)
Humans , Adult , Gram-Negative Bacterial Infections/microbiology , Gram-Negative Bacterial Infections/epidemiology , Bacterial Proteins , beta-Lactamases/genetics , Cephalosporins/pharmacology , Disease Outbreaks , Gram-Negative Bacteria/genetics , Anti-Bacterial Agents/pharmacologyABSTRACT
We investigated the third-generation cephalosporins-resistant Shigella and its genotype in Ningbo,China,providing a basis for disease prevention and control.Pathogenic bacteria were analyzed by direct isolation combined with enrichment culture isolation.Antimicrobial susceptibility was determined by K-B disk diffusion method and PCR was used for detecting multidrug resistance genes like CTX-M,OXA,TEM and SHV.BLAST analysis was used to determine the genotype.Results showed that 69 strains of third-generation cephalosporins-resistant Shigella were detected by drug sensitivity screening,accounting for 74.19％ of ESBLs Shigella.Drug resistance gene CTX-M(CTM-M-1 and CTM-M-9),OXA and TEM were detected.The detection rate were 79.71％,79.01％ and 26.09％ respectively.With no CTX-M-2 and SHV,DNA sequence alignment showed CTX-M-1 group were mainly of CTX-M-15 type besides seven other types;CTX-M-9 group were mainly of CTX-M-14 type besides six other types;49 strains of OXA and 18 strains of TEM were sequenced to be type 1 (OXA-1 and TEM-1 type).The 21 Shigella strains carrying more than two drug resistance genes accounts for 30.43 ％.Shigella in Ningbo has high third-generation cephalosporins-resistance rate and many kinds of ESBLs enzymes were detected.The mainstream enzyme type was CTX-M,meanwhile they also carried a variety of drug resistance genes,which could bring difficulties to disease prevention and control.The high carrying rate of OXA-1 type suggests that we should pay more attention.The detection rate of group B was higher than that of group D,including not only the phenotype resistance but also the drug-resistance genes;these findings will be useful in the study of the drug resistance prevalence of Shigella.
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Objectives: Evaluate risk factors and clinical outcomes of infections caused by Enterobacteriaceae resistant to third-generation cephalosporins present in samples collected upon hospital admission. Methods: Risk factors were evaluated using a 1:2 ratio case-control study. Influence of resistance on the appropriateness of antibiotic therapy, length of stay, and hospital mortality were prospectively evaluated. Characteristics independently associated with the presence of resistant enterobacteria were assessed by logistic regression. Results: Enterobacteria resistant to third-generation cephalosporins were quite common (26.0%). Male gender (OR: 2.66; 95% CI, 1.17-5.06; p = 0.019), invasive prosthesis (OR: 3.79; 95% CI, 1.29-11.08; p = 0.015), previous use of cephalosporins (OR: 2.77; 95% CI, 1.10-6.97; p = 0.029) and hospitalization in the last 6 months (OR: 5.33; 95% CI, 2.29-12.44; p < 0.001) were independently associated with the presence of these microorganisms. These bacteria were associated with higher frequency of inappropriate antimicrobial therapy, worse clinical response, and longer length of stay. Finally, older age, admission to the ICU, and site of infection other than urinary tract were independently associated to higher hospital mortality. Conclusions: Risk factors identified in this study may help in the choice of empirical antibiotic therapy for infected patients suspected of harboring these bacteria and in the early implementation of measures to avoid the spread of these bacteria in the hospital environment. .
Subject(s)
Female , Humans , Male , Middle Aged , Anti-Bacterial Agents/therapeutic use , Cephalosporin Resistance , Cephalosporins/therapeutic use , Enterobacteriaceae Infections/drug therapy , Enterobacteriaceae Infections/microbiology , Enterobacteriaceae/drug effects , Case-Control Studies , Enterobacteriaceae/classification , Hospitals, University , Risk Factors , Treatment OutcomeABSTRACT
Background: Newer generation cephalosporin-resistance among Klebsiella pneumoniae organisms has increased recently. Present study is undertaken to find incidence, antimicrobial susceptibility and prevalence of extended spectrum beta-lactamase (ESBL) in K. pneumoniae isolates in a tertiary care hospital. Methods: Prospective study was carried out between June to December 2011. Samples of pus, blood, urine, cerebro-spinal fluid, stool, peritoneal, pleural and synovial fluid were collected from indoor and outdoor patients for isolation and antimicrobial susceptibility pattern of K. pneumoniae in the department of microbiology, G.R. Medical College Gwalior, M.P. Ceftazidime resistant K. pneumoniae were subjected to Phenotypic Confirmatory Disc Diffusion Test (PCDDT) and Double Disc Synergy Test (DDST) for detection of ESBL. Results: Out of 2480 samples collected a total of 530 K. pneumoniae were isolated and subjected to antimicrobial susceptibility. Antibiotic sensitivity to imipenem, cefoperazone, amikacin and ofloxacin were 82, 74, 73 and 72% respectively whereas sensitivity to ceftizoxime, ceftriaxone cefotaxime, ceftazidime ranged between 47-50%. K. pneumoniae were found to be resistant to ampicillin, co-trimoxazole, doxycycline and gentamicin, by 91, 82, 54 and 50% respectively. Among third generation cephalosporins K. pneumoniae were least sensitive (47%) to ceftazidime. About 33 and 32% of the ceftazidime resistant strains were found to be ESBL positive by PCDDT and DDST respectively. Conclusions: This study has shown that prevalence of ESBL producing K. pneumoniae is the most important reason for increased resistance to third generation cephalosporins. There is need to carry out tests for detection of ESBL producing bacteria routinely.
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OBJECTIVE To investigate extended-spectrum ?-lactamases(ESBLs) producing bacteria and daily(defined) doses (DDDs) of the third generation cephalosporins.METHODS The cosumpsion of the third generation cephalosporins in five(hospitals) from 2000 to 2002 and the incidence of ESBLs producing bacteria were(analyzed).RESULTS In these years,the total DDDs were 1.3064 million therapeutic days,0.3335 million in 2000;0.4312 million in 2001;(0.5417) million in 2002.The average ESBLs producing ratio was 33.67%,ie,29.64%,32.58% and(38.45%) in 2000,2001 and 2002.CONCLUSIONS The incidence of ESBLs producing bacteria and DDDs of the third generation cephalosporins are raised gradually. More faster raised DDDs would result in higher incidence of ESBLs producing bacteria.
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BACKGROUND: Among Gram-negative pathogens in Korea, the incidence of resistance to thirdgeneration cephalosporins is becoming an ever-increasing problem. This study was designed to determine the prevalence of third-generation cephalosporins-resistant Escherichia coli and Klebsiella pneumoniae isolates from patients in a tertiary care hospital in Busan, Korea, and to characterize the mechanism of resistance. METHODS: A total of 710 E. coli and 237 K. pneumoniae non-duplicate isolates were collected from patients in Kosin Medical Center in 1999. Antimicrobial susceptibilities were tested by the disk diffusion method. Extended-spectrum beta-lactamase (ESBL) production was determined by the double disk synergy test. MICs were determined by the agar dilution method. Searches for blaTEM, blaSHV, and blaCMY genes in cefotaxime-resistant or intermediate isolates were performed by PCR amplification. PCR products were used to determine the sequence of resistance genes by the dideoxy-chain termination method. RESULTS: Seven percent of E. coli and 25% of K. pneumoniae isolates were resistant to cefotaxime. Among the isolates with decreased susceptibility to cefotaxime, 69% (18/26) of E. coli and 80% (20/25) of K. pneumoniae isolates showed positive results in double disk synergy test. Banding patterns of PCR amplification showed that the blaTEM, blaSHV, and blaCMY genes were harboured by 71% (20/28), 86% (24/28) and 14% (4/28) of isolates with decreased susceptibility to cefotaxime,respectively. Seventy-one percent (20/28) of the isolates contained more than two types of beta- lactamase genes. Nucleotide sequence analysis of PCR products revealed that blaSHV-12 and blaTEM-1b were the dominant types of beta-lactamase gene. In addition, we also identified blaTEM-52, blaSHV-5, and a new ESBL gene named blaTEM-17b. CONCLUSIONS: Third-generation cephalosporins-resistant E. coli and K. pneumoniae are wide spread in Kosin Medical Center, Busan, Korea. Most of the isolates with decreased susceptibility to cefotaxime had blaTEM and/or blaSHV, and some isolates harboured blaCMY genes that may confer resistance against cephamycins. The spread of these beta-lactamase genes could compromise the future usefulness of third-generation cephalosporins for the treatment of infections caused by E. coli and K. pneumoniae.
Subject(s)
Humans , Agar , Base Sequence , beta-Lactamases , Cefotaxime , Cephalosporins , Cephamycins , Diffusion , Escherichia coli , Escherichia , Incidence , Klebsiella pneumoniae , Klebsiella , Korea , Pneumonia , Polymerase Chain Reaction , Prevalence , Tertiary HealthcareABSTRACT
BACKGROUND: Increased isolation of extended-spectrum beta-lactamase (ESBL)-producing Entero bacteriaceae resistant to third generation cephalosporins and aztreonam has been noted recently. This study was to determine the prevalence of resistance to these drugs and ESBL in Enterobacteriaceae and to evaluate the methods for de tection. METHODS: During the period of October, 1997 and March, 1998, a total of 731 clinical isolates of Enterobacteriaceae were collected from patients of the Kosin Medical Center, Pusan, Korea. Antimicrobial susceptibility test by disk diffusion method and double disk synergy test were performed. MICs of beta-lactams were determined by agar dilution method. And ESBL genotypes were determined by polymerase chain reaction. RESULTS: About 10% of Escherichia coli isolates and 20% of Klebsiella pneumoniae isolates were intermediate or resistant to the third generation cephalosporins or aztreonam. Sensitivities of cefotaxime, ceftazidime, ceftriaxone and cefpodoxime disks for the detection of ESBL- producing strains of E. coli and K. pneumoniae by NCCLS standards were 100%, respectively, but that of aztreonam disk was 97%. Positive predictive value of the ceftazidime disk was higher than those of other disks. Twenty strains of E. coli, 20 K pneumoniae, 19 Enterobacter spp., six Citrobacter freundii, and eight Serratia marcescens showed positive results in double disk synergy test. The transconjugant strain of K. pneumoniae K20482 had blaSHV, and remains of transconjugants of ESBL-producing K. pneumoniae, Enterobacter spp. and S. marcescens had blaTEM. CONCLUSIONS: In this study, many strains of Enterobacteriaceae isolated in Korea were resistant to third generation cephalosporins and aztreonam. Some of the strains of Enterobacter spp. and S. marcescens as well as E. coli and K. pneumoniae produced ESBL, and majority of these strains had blaTEM. In the detection of ESBL-producing strains of E. coli and K. pneumoniae by NCCLS standards, all of the antimicrobial agent disks tested were useful, but ceftazidime disk was most effective because of its highest positive predictive value.