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.     

Economic value of Acinetobacter baumannii screening in the intensive care unit

Although Acinetobacter baumannii (A. baumannii) is an increasingly common nosocomial pathogen that can cause serious infections in the intensive care unit (ICU), most ICUs do not actively screen admissions for this pathogen. We developed an economic computer simulation model to determine the potential cost-consequences to the hospital of implementing routine A. baumannii screening of ICU admissions and isolating those patients who tested positive, comparing two screening methods, sponge and swab, with each other and no screening. Sensitivity analyses varied the colonization prevalence, percentage of colonized individuals who had active A. baumannii infections, A. baumannii reproductive rate (R), and contact isolation efficacy. Both screening methods were cost-effective for almost all scenarios tested, yielding cost-savings ranging from -$1 to -$1563. Sponge screening was not cost-saving when colonization prevalence was ≤1%, probability of infection ≤30%, R ≤ 0.25, and contact isolation efficacy ≤25%. Swab screening was not cost-saving under these same conditions when the probability of infection was ≤40%. Sponge screening tended to be more cost-saving than swab screening (additional savings ranged from $1 to $421). Routine A. baumannii screening of ICU patients may save costs for hospitals.     

某院2011年重症监护病房鲍曼不动杆菌感染的耐药性分析

目的了解某院2011年重症监护病房（ICU）内鲍曼不动杆菌的耐药情况,为预防与治疗鲍曼不动杆菌感染提供依据。方法回顾性调查某院2011年ICU35例鲍曼不动杆菌感染病例的标本分布、耐药性、危险因素和抗菌药物使用情况。结果 ICU鲍曼不动杆菌主要来源于痰标本（35株,占85.37%）,其次为创面分泌物（3株,占7.31%）。有基础疾病、侵入性操作、前期使用抗菌药物和激素、入住ICU、住院时间大于60d等是感染鲍曼不动杆菌的高危因素。鲍曼不动杆菌对头孢哌酮舒巴坦（100.0%）及亚胺培南西司他汀（92.5%）的敏感率较高,对其他16种抗菌药物的耐药率均在50.0%以上。临床治疗鲍曼不动杆菌感染多经验性选择第三代头孢菌素、喹诺酮及广谱青霉素类抗菌药物。结论 ICU内鲍曼不动杆菌耐药情况严重,控制感染的关键在于注意高危因素的防范,加强对该菌的耐药监测,合理使用抗菌药物。     

Variable resistance patterns of integron-associated multidrug-resistant Acinetobacter baumannii isolates in a surgical intensive care unit

Between 1998 and 2000, we characterized 91 nosocomial isolates of Acinetobacter baumannii by antibiotyping and genotyping. A total of 25 ribotypes were obtained among these 91 isolates. When the isolates from surgical intensive care units (ICUs) and other wards were compared, multiresistant A. baumannii isolates with the same ribotype 25 (R-25) were significantly more prevalent in nosocomial infections among the surgical patients. Further subtyping of the strains by pulsed-field gel electrophoresis confirmed that strains of the same ribotype in surgical ICUs and a few isolates from other wards were identical or clonally related. Different antibiotic resistance profiles were observed among these R-25 isolates. All R-25 isolates contained intI1 integrase, and two clusters of integron cassettes were found. These clusters of cassettes were encoded by an open reading frame (ORF) of -5'CS-aac(3)Ia-aadA1a-unknown or f-3'CS or 5'CS-aacA4-aadA1-catB8-3'CS, indicating the involvement of different resistant genes. Two isolates contained bla (IMP-1), which was acquired from a conjugatively transferable plasmid and did not involve integron-associated resistance. In conclusion, an epidemic of nosocomial infections associated with A. baumannii strains that have different resistance profiles was identified. Resistance profiles can change by a combination of plasmid- and integron-associated acquisition, especially in a unit with high antibiotic selective pressures. Infectious control personnel should be alert to the change in resistance profiles during routine monitoring.     

Long persistence of methicillin-susceptible strains of Staphylococcus aureus causing sepsis in a neonatal intensive care unit

Molecular epidemiology of Staphylococcus aureus strains causing bacteremia in neonates during 2002 to 2005 revealed seven clones, with four MSSA clones responsible for 80% of the cases. Some clones persisted or reappeared throughout the study. Three bacteremic clones were found colonizing health care workers (HCWs), particularly clone C, which was harbored by at least 15% of HCWs.     

Molecular epidemiology of sequential outbreaks of Acinetobacter baumannii in an intensive care unit shows the emergence of carbapenem resistance

The molecular epidemiology of multidrug-resistant Acinetobacter baumannii was investigated in the medical-surgical intensive care unit (ICU) of a university hospital in Italy during two window periods in which two sequential A. baumannii epidemics occurred. Genotype analysis by pulsed-field gel electrophoresis (PFGE) of A. baumannii isolates from 131 patients identified nine distinct PFGE patterns. Of these, PFGE clones B and I predominated and occurred sequentially during the two epidemics. A. baumannii epidemic clones showed a multidrug-resistant antibiotype, being clone B resistant to all antimicrobials tested except the carbapenems and clone I resistant to all antimicrobials except ampicillin-sulbactam and gentamicin. Type 1 integrons of 2.5 and 2.2 kb were amplified from the chromosomal DNA of epidemic PFGE clones B and I, respectively, but not from the chromosomal DNA of the nonepidemic clones. Nucleotide analysis of clone B integron identified four gene cassettes: aacC1, which confers resistance to gentamicin; two open reading frames (ORFs) coding for unknown products; and aadA1a, which confers resistance to spectinomycin and streptomycin. The integron of clone I contained three gene cassettes: aacA4, which confers resistance to amikacin, netilmicin, and tobramycin; an unknown ORF; and bla(OXA-20), which codes for a class D beta-lactamase that confers resistance to amoxicillin, ticarcillin, oxacillin, and cloxacillin. Also, the bla(IMP) allele was amplified from chromosomal DNA of A. baumannii strains of PFGE type I. Class 1 integrons carrying antimicrobial resistance genes and bla(IMP) allele in A. baumannii epidemic strains correlated with the high use rates of broad-spectrum cephalosporins, carbapenems, and aminoglycosides in the ICU during the study period.     

Nosocomial nasal myiasis in an intensive care unit

A 73-year-old Chinese man was admitted to the Accident and Emergency Premorbid Ward of a local hospital in Malaysia. The patient complained of shortness of breath with cough and was in a semi-conscious state. He was later admitted to an intensive care unit (ICU) of the hospital. Six days after admission 5-6 maggots were recoverd from the nasal cavity. The maggots were identified as the third-instar larvae of Lucilia cuprina Wiedmann (Diptera: Calliphoridae) based on the morphological characteristics. This patient was classified as having nosocomial myiasis. The presence of the third instar larvae indicated that the infestation was not more than three to four days. An adult sarcophagid identified as Parasarcophaga ruficornis (Fabricius) caught in the ICU where the patient was warded provided further evidence of the potential for the nosocomial infestation.     

Antimicrobial usage in an intensive care unit: a prospective analysis

Antimicrobial therapies in the Intensive Care Unit (ICU) need to be appropriate in both their antimicrobial cover and duration. We performed a prospective observational study of admissions to our semi-closed ICU over a three-month period and recorded the indications for antimicrobial therapy, agents used, duration of use, changes in therapy and reasons for changes in therapy. A change in therapy was defined as the initiation or discontinuation of an antimicrobial agent. There were 51 patients admitted during the three-month study period and all received antimicrobial therapy. There were 135 changes in antimicrobial therapy. 89 (66%) were made by the ICU team and 32 (24%) were made by the primary team. Changes were made due to a deterioration or lack of clinical response in 41 (30%) cases, due to the completion of prescribed course in 36 (27%) cases, and in response to a sensitivity result in 25 (19%) cases. Prophylactic antibiotic courses (n=24) were of a duration greater than 24 hours in 15 (63%) instances. In conclusion, the majority of changes in antimicrobial therapy were not culture-based and the duration of surgical prophylaxis was in excess of current recommended guidelines.     

Cholestasis in a neonatal intensive care unit

A retrospective study of 17 babies admitted to the neonatal intensive care unit of the Royal Maternity Hospital, Belfast, was undertaken to determine the causes and prognosis of conjugated hyperbilirubinaemia (direct fraction greater than 20% of total) over a five year period. Mean gestational age was 29 weeks and mean birth weight was 1,240g with a 2:1 male preponderance. All babies had a complicated clinical course involving prolonged periods of parenteral nutrition and many episodes of sepsis. Liver damage was not found to be a contributory factor to death in any baby who died before the age of one year. Bilirubin levels in the survivors had returned to normal within one year. No permanent pathological cause of cholestasis, such as biliary atresia, was ascribable to any of the cases, indicating that extensive investigation to exclude anatomical causes in this population is unlikely to prove rewarding.     

Successful management of an MRSA outbreak in a neonatal intensive care unit

We report an MRSA outbreak in our 25-bed tertiary neonatal intensive care unit (NICU), which was successfully contained. Methods include a retrospective review of patient files, microbiology records and meeting protocols. During the seven months of outbreak, 27 patients and seven health care workers (HCWs) had positive cultures for MRSA. The outbreak was caused by the epidemic Rhine-Hessen strain; cultured isolates were monoclonal. After a sharp increase of the number of new MRSA-cases the installation of an outbreak management team (OMT) and implementation of comprehensive measures (extensive screening and decolonization strategy including orally applied vancomycin, isolation wards, intensive disinfection regimen) successfully terminated the outbreak within one month. Ten (53%) of 19 patients with completed follow-up and all of the HCWs were decolonized successfully. Gastrointestinal colonization was present in 15 of 27 (56%) neonates, and was associated with poor decolonization success (30% vs. 78% in absence of gastrointestinal colonization). A comprehensive outbreak management can terminate an outbreak in a NICU setting within a short time. Thorough screening of nares, throat and especially stool is necessary for correct cohorting. Gastrointestinal decolonization in neonates seems difficult.     

Microbiological surveillance in an intensive care unit of a large Roman hospital

Infection surveillance in ICU is fundamental to monitor endemic rates, to identify outbreaks on-time in order to activate control procedures implementing a correct empirical antibiotic treatment. The data collection surveillance software CIN-20002 was established in the Teaching Hospital Umberto I ICU to monitor the following site-specific infection rates: urinary tract infections (UTI), pneumonia (PNE), blood stream infections (BSI), surgical site infections (SSI). According to CDC definitions all patients developing infection 48 hours or more after ward admission were included. Furthermore risk factors (i.e. age, sex, SAPS II), invasive procedures (i.e. endotracheal intubation, vascular and urinary catheterisation), microbiological isolates and their antibiotic susceptibility were screened. Overall 279 patients (183 men and 96 women) were admitted; age 54,8 20,3 years (mean), SAPS II 44,4 17,1 (mean) and average ward stay 13,3 17,8 days. Results showed a total of 121 infection episodes (56 PNE, 51 BSI, 10 UTI e 4 SSI) in 80 patients (28,7%). Standardized infection rates associated to invasive procedures were: Urinary catheter-associated UTI rate (2.9/1000), Ventilator-associated PNE rate (20.4/1000), Vascular catheter-associated BSI rate (19.1/1000). Among the infected patients the most common microrganisms isolated were P. aeruginosa (31,8%), MRSA (14,8%), A. baumanni (12,5%) e S. maltophilia (8,5%). Considering site-specific infections: PNE (P. aeruginosa 38,3% and MRSA 18,1%), BSI (MR CNS 21,9% and P. aeruginosa 17,2%), UTI (P. aeruginosa 70,0%). The surveillance software CIN-2000 proved to be very accurate, usefull and easy to use. The results showed a high incidence of infections associated to invasive procedures and the presence of multiresistant bacteria     

Comparison of methods for measuring antibiotic consumption in an intensive care unit

Hospitals worldwide are working on minimizing unnecessary use of antimicrobials. To assess actual changes of antimicrobial usage, correct and precise measurements are necessary. This study aimed to compare data on the purchase of antibiotics from the pharmacy and the administration of antibiotics to patients, respectively, in an intensive care unit (ICU). Data were obtained from the Neurointensive Care Unit (NICU) at Rigshospitalet, Denmark. During a 23‐month period, comprising 10 770 bed‐days (BD), the ward purchased 16 908 defined daily doses (DDD) of antibiotics from the pharmacy, and 15 130 DDD and 41 304 individual doses were administered. Intraclass correlation coefficients (ICCs) were calculated; control and runcharts and a Bland–Altman plot were constructed. Pharmacy sales and drug administration data showed no systematic variation over time with a monthly overestimation of pharmacy sales data of 10% (95% confidence interval (CI), 6.20–14.3%) for all antibiotics, and 7% (95% CI: 1.81–11.1%) for broad‐spectrum antibiotics. The antibiotic consumption, without bed‐days, has a clinically acceptable ICC of >0.70 and no systematic difference is suggested by the Bland–Altman plot. In this study of a large NICU, whose antibiotic consumption varied at random, pharmacy sales data were an acceptable approximation of the actual summarized drug consumption.     

Nosocomial spread of a Staphylococcus capitis strain with heteroresistance to vancomycin in a neonatal intensive care unit

A premature infant in a neonatal intensive care unit (NICU) developed a bloodstream infection caused by coagulase-negative staphylococci (CoNS) sensitive to vancomycin. The infection persisted for 3 weeks, despite therapy with vancomycin and replacement of all intravenous catheters. The neonate died due to necrotizing enterocolitis which developed during the ongoing sepsis. We screened this strain and 216 other strains of CoNS from cultures of blood obtained from neonates between 1997 and 2000 for heteroresistance to vancomycin. Forty-eight isolates, including the strain that caused ongoing sepsis, proved heteroresistant. All isolates were identified as Staphylococcus capitis and were identical, just as their resistant stable subcolonies were, when they were genetically fingerprinted by amplified-fragment length polymorphism analysis. The heteroresistant phenotype of this endemic strain was confirmed by population analysis. We conclude that heteroresistance to vancomycin occurs in S. capitis and might be the cause of therapeutic failures in NICUs. Moreover, heteroresistant strains can become endemic in such units.