High frequency of antibiotic resistance among Gram-negative isolates in intensive care units at 10 Swedish hospitals

Objective: To investigate the resistance rates among Gram-negative isolates in Swedish intensive care units (ICUs).
Method: During 1994–95, members of the Swedish Study Group collected, on clinical indication, 502 consecutive initial isolates of Gram-negative bacteria from patients admitted to ICUs at 10 Swedish hospitals and performed minimal inhibitory concentration (MIC) determinations with the Etest. Breakpoints were defined according to the criteria of the Swedish Reference Group for Antibiotics (SRGA).
Results: The distribution of bacterial species was: Escherichia coli > Klebsiella spp. > Enterobacter spp. > Pseudomonas aeruginosa > Haemophilus spp. > Proteus spp. > Stenotrophomonas maltophilia > Citrobacter spp. > Acinetobacter > Pseudomonas. spp. > Morganella morganii > Serratia spp. Together these constituted 97% of all isolates. The frequencies of resistance for all the initial Gram-negative isolates were: ceftazidime 6.8%, cefotaxime 14.9%, ceftriaxone 18.5%, cefuroxime 44.1%, ciprofloxacin 4.2%, co-trimoxazole 17.8%, gentamicin 5.8%, imipenem 8.6%, piperacillin 20.2%, piperacillin/tazobactam 12.9% and tobramycin 5.8%.
Conclusions: Among Gram-negative isolates in Swedish ICUs, a very high frequency of resistance was seen to cefuroxime, and rather high frequencies of resistance to cefotaxime, ceftriaxone, piperacillin and piperacillin/tazobactam. These drugs cannot be recommended for further use as empirical monotherapy for severe ICU-acquired Gram-negative infections in ICUs in Sweden.     

Antibiotic sensitivity of enterobacteria in intensive care units

Antibiotic therapy of intensive care patients is usually undocumented. The treatment is chosen according to epidemiologic and susceptibility data from microbiological laboratories. The aim of our study is to determine antibiotic susceptibility of enterobacteria isolated from intensive care patients during a five-month multicenter study in 18 French hospitals. Numerous (n = 1,113) strains were studied: 447 enterobacteria isolated from urine (n = 229), blood cultures (n = 106), respiratory tract specimens (n = 72), peritoneal fluids (n = 22), pus (n = 15) and catheters (n = 2). MICs of group 2 and group 3 enterobacteria were determined using the dilution agar method and were interpreted according to the CASFM (Comité de l'antibiogramme de la société fran?aise de microbiology) recommendations. Group 1 enterobacteria were most frequently isolated (67%). Only one Escherichia coli strain produced ESBL (0.3%). Among group 2 enterobacteria, one Citrobacter koseri strain produced ESBL. We did not isolate Klebsiella pneumoniae ESBL. Isolation of group 3 enterobacteria was frequent (24%). Thirty-five percent of group 3 enterobacteria were resistant to cefotaxime, 26% to ceftazidime and 16% to cefepime and cefpirome. Fourteen strains of this group produced ESBL: 13 Enterobacter aerogenes and one E. amnigenus.     

Spectrum and antibiotic susceptibility pattern of bacterial isolates from conjunctival swabs

Conjunctivitis is the most common disease of conjunctiva which occurs by exogenous or endogenous source. Bacterial conjunctivitis is the most common type of this infection for which emperical treatment is started without knowing the etiological agents because prior cultures are generally not taken. We conducted this survey to study the etiological agents of conjunctivitis in a total of 6763 swabs obtained over a period of four years (2001 to 2004). The prevalence of bacterial conjunctivitis was found to be 20.4% with a predominance of Staphylococcus aureus (87.2%) followed by Streptococcus pneumoniae (4.7%) and gram negative rods (E.coli + Klebsiella spp. + Pseudomonas spp.) in 8.1% swabs. For S. aureus, amikacin showed maximum sensitivity (73.2%) while for S. pneumoniae, cefotaxime (90.6%) and cefazolin (89%) were found to be highly sensitive drugs. For gram negative rods, ceftazidime (74.1%) and cefotaxime (67%) were found to be preferred options. Thus it is concluded that bacterial conjunctivitis in our hospital is predominated by S. aureus. The bacterial isolates obtained from conjunctiva have not yet attained a high level of antibiotic resistance and hence averts the need to unnecessarily start new/latest generations of antibiotic eyedrops or antibiotic combination which may lead to acquisition of resistance by these bacteria.     

Thirteen years of antibiotic susceptibility surveillance of Pseudomonas aeruginosa from intensive care units and urology services in the Netherlands

The purpose of this study was the evaluation of trends in the antimicrobial resistance of Pseudomonas aeruginosa from intensive care unit (ICU) patients and urology patients in the Netherlands. From 1998 to 2010, 1,927 consecutive P. aeruginosa isolates from ICU (n?=?1,393) and urology service patients (n?=?534) of 14 university and referral hospitals all over the Netherlands were collected and their susceptibility to relevant antibiotics was determined according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Over time, a significant upward trend in the resistance of P. aeruginosa strains collected from ICUs to piperacillin (1.2 % to 10.6 %, p?=?0.0175), piperacillin–tazobactam (1.2 % to 12.1 %, p?=?0.0008), ceftazidime (1.2 % to 7.8 %, p?=?0.0064), cefepime (4.8 % to 6.4 %, p?=?0.0166), imipenem (6 % to 19.1 %, p?<?0.0001), meropenem (8.3 % to 17 %, p?=?0.0022) and ciprofloxacin (13.1 % to 31.2 %, p?=?0.0024) was observed, as was the prevalence of multi-resistance (1.2 % to 8.5 %, p?=?0.0002). For P. aeruginosa isolates from the urology services, the resistance to imipenem increased (4.1 % to 7.8 %, p?=?0.0006) and to ciprofloxacin it decreased (22.4 % to 18.8 %, p?=?0.025). Like in other countries, in the Netherlands, an increase in multi-resistant Gram-negatives is observed, suggesting the presence and dissemination of several mechanisms of resistance. Our findings emphasise the importance of local surveillance for the setting up of local antibiotic guidelines and to support optimal empiric therapy. With the observed increase in multi-resistance, the direct testing of alternative antibiotics like polymyxins and fosfomycin is essential. Our data also illustrate the importance of adequate outbreak control measures.     

Characterization of Acinetobacter baumannii from intensive care units and home care patients in Palermo, Italy

In this study 45 isolates of Acinetobacter baumannii identified from patients in intensive care units of three different hospitals and from pressure ulcers in home care patients in Palermo, Italy, during a 3-month period in 2010, were characterized. All isolates were resistant to at least three classes of antibiotics, but susceptible to colistin and tygecycline. Forty isolates were non-susceptible to carbapenems. Eighteen and two isolates, respectively, carried the bla(OXA-23-like) and the bla(OXA-58-like) genes. One strain carried the VIM-4 gene. Six major rep-PCR subtype clusters were defined, including isolates from different hospitals or home care patients. The sequence type/pulsed field gel electrophoresis group ST2/A included 33 isolates, and ST78/B the remaining 12. ST2 clone proved to be predominant, but a frequent involvement of the ST78 clone was evident.     

Prevalence of fragilysin gene in Bacteroides fragilis isolates from blood and other extraintestinal samples

Of 166 Bacteroides fragilis isolates, 26.2% of 103 isolates from blood and 20.6% of 63 extraintestinal isolates harbored the fragilysin gene (difference not statistically significant). Clinical characteristics and evolution were comparable in patients with B. fragilis bacteremia with or without this enterotoxin. Fragilysin seems not to be an important virulence factor in B. fragilis disease.     

Multicenter surveillance of antimicrobial resistance of major bacterial pathogens in intensive care units in 2000 in Taiwan

A susceptibility surveillance study of 1,274 bacterial isolates recovered from various clinical specimens from patients in intensive care units (ICUs) of five major teaching hospitals was carried out from March, 2000, to June, 2000, in Taiwan. This study demonstrated a high rate (66%) of oxacillin resistance in Staphylococcus aureus (ORSA), a high rate of nonsusceptibility to penicillin (intermediate, 50% and highly resistant, 8%), and high rates of cefotaxime nonsusceptibility for S. pneumoniae (intermediate, 29% and resistant, 4%), Enterobacter cloacae (57%), Serratia marcescens (34%), and Citrobacter freundii (60%). High rate of ceftazidime nonsusceptibility for Pseudomonas aeruginosa (22%), and high rates of imipenem nonsusceptibility for P. aeruginosa (15%) and Acinetobacter baumannii (22%) were also found. The percentage (11.9%) of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli was greater than that (11.3%) for Klebsiella pneumoniae. Rates of quinupristin-dalfopristin nonsusceptibility for S. pneumoniae (42%), Enterococcus faecium (71%), and ORSA (39%) were high, but no vancomycin-resistant enterococci were found in this study. The resistance rates of some pathogen varied by institution or type of ICUs. Surveillance for antimicrobial resistance among bacterial pathogens in hospitals, particularly in ICU settings with a preexisting higher resistance burden, is mandatory in establishing and/or modifying guidelines for empirical treatment of severe infections in ICU patients caused by these antimicrobial-resistant pathogens.     

Indications and results of endoscopic examinations in intensive care units

The aim of the study was to analyze retrospectively all endoscopies performed on 3 intensive care units in a tertiary referral center with more than thousand beds during a period of ten years. The study evaluates all endoscopies with regard to indication and findings. In the years 1989-1998 a total of 326 endoscopic examinations was performed, most of them were done as an upper gastrointestinal endoscopy (88%). In more than 87% the indication was a suspected gastrointestinal bleeding. The most frequent findings consisted in ulcers of the stomach or duodenum and esophageal varices, then followed by Mallory-Weiss-lesions, esophagitis and erosive gastritis. The etiology of gastrointestinal bleeding was similar to that of non intensive care patients. Specific causes of bleeding such as esophagitis caused by nasogastric tubes were only found in 3% of all bleedings. The numbers of endoscopies on the 3 intensive care units were increasing during the ten year period, however the numbers of the patients treated on the intensive care units were also increasing, but the increase of endoscopies was not always parallel to the rising number of intensive care patients.     

The role of integrons in the dissemination of antibiotic resistance among clinical isolates of Pseudomonas aeruginosa from an intensive care unit in Brazil

Eighty-five Pseudomonas aeruginosa isolates resistant to various antibiotics were selected from the intensive care unit of a Brazilian hospital and analyzed for integron content by PCR. Fifty-four of them had class-1-related integrons, some of which were identical. Integron-positive isolates were statistically more resistant to aminoglicoside, quinolone and beta-lactam compounds. Ribotyping of integron-positive isolates demonstrated the presence of identical integrons among genetically unrelated strains in the hospital environment, confirming its role in the spread of gene cassettes in bacterial populations of clinical importance.     

Molecular epidemiologic analysis of methicillin-resistant Staphylococcus aureus isolates from bacteremia and nasal colonization at 10 intensive care units: multicenter prospective study in Korea

We investigated molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolated at 10 intensive care units (ICUs) in Korea. MRSA isolates from bacteremia and nasal colonization were collected prospectively from October 2008 through May 2009 at 10 University-affiliated hospital ICUs. A total of 83 and 175 MRSA strains were isolated from bacteremia and nasal colonization, respectively. Acquired group accounted for 69.9% (n = 58) of bacteremia and 73.1% (n = 128) of nasal colonization. Pulsed-field gel electrophoresis (PFGE) type B (SCCmec type II/ST5) was dominant in the acquired group followed by PFGE type D (SCCmec type IVA/ST72; a community genotype). Seven of 58 (12.1%) acquired bacteremia and 15 of 128 (11.8%) acquired nasal colonizations had SCCmec type IVA/ST72 genotype, which indicated that the community genotype had already emerged as a cause of ICU acquired MRSA infection or colonization. Antibiotic resistance rates to ciprofloxacin, tetracycline, clindamycin and trimethoprim/ sulfamethoxazole were 84.4%, 67.1%, 78.1%, and 12.0%, respectively. Susceptibility to ciprofloxacin best predicted a community genotype (sensitivity 96.5%; specificity 96.9%; odds ratio 861; 95% confidence interval 169-4,390, P < 0.001) and the positive predictive value was 90.2%. Among 23 nasal re-colonized strains, 7 MRSA strains (30.4%) were different from the originally colonized strains on the basis of PFGE types.     

Detection of cross-transmission of multiresistant Gram-negative bacilli and Staphylococcus aureus in adult intensive care units by routine typing of clinical isolates

Objective: To determine the potential of laboratory services in identifying cross-transmission of multiresistant Gram-negative bacilli (MR GNB) and Staphylococcus aureus in adult intensive care units by routine typing of clinical isolates.
Methods: Over a 12-month period, isolates with indistinguishable PCR fingerprints were traced back to the source patients and their epidemiologic relationships were investigated. Possible episodes of cross-transmission were ascertained, and the validity of antibiograms in identifying the same cluster assessed.
Results: Of 3503 specimens received by the microbiological laboratory during 5372 patient days, 1295 cultures showed bacterial growth. Of these, 132 were primary isolates of MR GNB and 92 were primary isolates of S. aureus . Thirty-two MR GNB isolates (24%) shared fingerprints with one or more other isolates. Indistinguishable isolates from epidemiologically related patients suggested 17 episodes of cross-transmission. The positive and negative predictive values of antibiogram-based identification of these episodes were 19% and 72% respectively. S aureus displayed limited genetic diversity. The two most frequent genotypes contained 19 and 16 isolates, of which the majority appeared to be epidemiologically unrelated.
Conclusions: Endemic transmission of MR GNB occurs mainly between two patients and remains unrecognized by conventional laboratory investigation. Rapid genetic typing methods identify patients involved in cross-transmission and give an insight into the population dynamics of MR GNB on adult intensive care units.     

Molecular typing ofAcinetobacter baumannii from ten different intensive care units of a university hospital

Thirty-one isolates ofAcinetobacter baumannii were collected from ten intensive care units of an Austrian university hospital. All isolates were typed by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). Two strains colonizing 13 infants in the neonatal intensive care unit were identified by ERIC-PCR. All otherAcinetobacter baumannii isolates had highly divergent ERIC-PCR patterns, despite having the same antibiogram. Thus, a hospital-wide clonal distribution, as suggested by identical antibiogram patterns, was excluded by ERIC-PCR.     

In vitro activities of doripenem and other carbapenems against clinically important bacteria isolated in intensive care units: nationwide data from the SMART Programme

This nationwide surveillance of clinically important bacteria from the intensive care units (ICUs) of major teaching hospitals throughout Taiwan investigated the susceptibilities to doripenem and other comparator carbapenems from September through November 2005. Minimum inhibitory concentrations (MICs) were determined for 1,311 clinical isolates using the broth microdilution method according to Clinical and Laboratory Standards Institute (CLSI) 2005 guidelines. Doripenem showed similar (within four-fold difference of MICs) in vitro activity to meropenem for Enterobacteriaceae and probably comparable activity to meropenem against important nosocomial non-fermentative Gram-negative bacilli (NFGNBs), including Pseudomonas aeruginosa, Acinetobacter baumannii and Burkholderia cepacia. Among the four carbapenems analysed, doripenem and meropenem exhibited better in vitro activity than imipenem or ertapenem against extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae and Escherichia coli isolates. However, the meropenem MIC₉₀ against ESBL-producing K. pneumoniae isolates was 2 µg/ml. Besides, doripenem with the MIC₉₀ of 0.5 µg/ml to Streptococcus pneumoniae possibly suggested its potential therapeutic effect regarding community-acquired pneumonia. Because of the heavy resistance burden in Taiwan, closely monitoring the evolutionary trend of carbapenem susceptibilities against clinically important pathogens is crucial in the future.     

Prevalence of PCR ribotypes among Clostridium difficile isolates from pigs, calves, and other species

PCR ribotypes were obtained for 144 Clostridium difficile isolates from neonatal pigs. Porcine isolates comprised four PCR ribotypes, but one, ribotype 078, predominated (83%). This was also the most common ribotype (94%) among 33 calf isolates but was rarely identified in other species.     

Metallo-beta-lactamase-producing clinical isolates of Acinetobacter species and Pseudomonas aeruginosa from intensive care unit patients of a tertiary care hospital

Prompt detection of metallo-beta-lactamase (MBL) producing isolates is necessary to prevent their dissemination. Frequency of MBLs producing strains among multidrug resistant (MDR) Acinetobacter species and Pseudomonas aeruginosa was evaluated in critical care patients using imipenem-EDTA disk method. One hundred MDR Acinetobacter spp. and 42 Pseudomonas aeruginosa were checked for MBL production, from January to June 2001. MBL was produced by 96.6 % of imipenem-resistant Acinetobacter isolates, whereas 100% imipenem-resistant Pseudomonas aeroginosa isolates were MBL producers. Carbapenem resistance in MDR Acinetobacter spp. and Pseudomonas aeruginosa isolates in this study was due to MBLs. This calls for strict infection control measures to prevent further dissemination.     

重症监护病房环境与临床分离耐碳青霉烯类鲍曼不动杆菌的REP-PCR分型研究

目的 调查上海市重症监护病房(ICU)环境中耐碳青霉烯类鲍曼不动杆菌(CRAB)的流行型别,并分析ICU的环境分离株与临床分离株的同源性.方法 对上海市21所医院ICU环境分离到的61株CRAB及其中一所医院(S医院)ICU临床分离到的14株CRAB,采用DiversiLab自动化重复序列(REP) -PCR分型系统,进行基因分型.结果 61株ICU环境分离的CRAB共分7型,其中G1型又分3个亚型,共46株细菌,占全部细菌的75.4％,分布于上海市的13所医院;G2、G3、G4、G5、G6和G7型分别为8株(13.1％)、2株(3.3％)、1株(1.6％)、1株(1.6％)、2株(3.3％)和1株(1.6％).在检出CRAB的13所医院中,除了D医院外,其他医院均分离到G1型CRAB.上海市S医院ICU共检出25株CRAB(14株临床株和11株环境株),分4型:其中G1型17株,为主要流行型别.由临床株和环境株的分布示意图显示:在外科ICU(SICU)中,环境株和临床株均以G1型为主,多个邻近床位病人检出G1型CRAB;心外科ICU(CICU)环境株以G1型为主,临床株以G2型为多,其中19床的病人及周围环境均检出G1型CRAB.结论 上海市ICU环境中普遍存在G1型CRAB流行株,各医院ICU环境中存在流行株交叉污染的现象,ICU临床分离的CRAB与环境分离株有较高的相关性.应加强ICU环境消毒和手卫生,防止医院感染的暴发和流行.     

Time comparison of intensive care units with and without digital viewing systems

As hospital radiology departments and intensive care units (ICUs) make plans to use or expand the usage of digital data outside of the radiology department, the need to assess the requirements of the potential recipients in the ICUs has become more important. The present operations in an ICU that uses digital viewing instead of film has been compared with a unit that does not. The difference in time between x-ray exposure and final image viewing was determined in both settings and compared. In this preliminary study, significant differences were found between the two units. The odds of having examination results actually accessed by the ordering physician in an hour or less were 9.5 times greater for the unit with digital viewing capability than for the one without it.