Rapid phenotypic antimicrobial susceptibility testing of Gram-negative rods directly from positive blood cultures using the novel Q-linea ASTar system.

Adequate and timely antibiotic therapy is crucial for the treatment of sepsis. Innovative systems, like the Q-linea ASTar, have been developed to perform rapid antimicrobial susceptibility testing (AST) directly from positive blood cultures (BCs). We conducted a prospective study to evaluate ASTar under real-life conditions with a focus on time-to-result and impact on antimicrobial therapy. Over 2 months, all positive BCs that showed Gram-negative rods upon microscopy were tested with the ASTar and our standard procedure (VITEK 2 from short-term culture). Additionally, we included multidrug-resistant Gram-negative bacteria from our archive. Both methods were compared to broth microdilution. In total, 78 bacterial strains (51 prospective and 27 archived) were tested. ASTar covered 94% of the species encountered. The categorical and essential agreement was 95.6% and 90.7%, respectively. ASTar caused 2.4% minor, 2.0% major, and 2.4% very major errors. The categorical agreement was similar to standard procedure. The average time between BC sampling and the availability of the antibiogram for the attending physician was 28 h 49 min for ASTar and 44 h 18 min for standard procedure. ASTar correctly identified all patients who required an escalation of antimicrobial therapy and 75% of those who were eligible for de-escalation. In conclusion, ASTar provided reliable AST results and significantly shortened the time to obtain an antibiogram. However, the percentage of patients that will profit from ASTar in a low-resistance setting is limited, and it is currently unclear if a change of therapy 29 h after BC sampling will have a significant impact on the patient's prognosis.

Comparison of nine different commercially available molecular assays for detection of SARS-CoV-2 RNA.

To face the COVID-19 pandemic, the need for fast and reliable diagnostic assays for the detection of SARS-CoV-2 is immense. We describe our laboratory experiences evaluating nine commercially available real-time RT-PCR assays. We found that assays differed considerably in performance and validation before routine use is mandatory.

Whole-genome analysis of vancomycin-resistant Enterococcus faecium causing nosocomial outbreaks suggests the occurrence of few endemic clonal lineages in Bavaria, Germany.

OBJECTIVES: Infections caused by vancomycin-resistant Enterococcus faecium (VREfm) represent a major public health concern due to limited treatment options. Among invasive isolates of VREfm, ST117, ST80 and ST78 represent the most frequently detected STs by MLST in Germany. In this study, we investigated the genetic diversity of isolates of VREfm recovered from different nosocomial outbreaks in Bavaria, Germany, by WGS. METHODS: Between January 2018 and April 2019, 99 non-replicate isolates of VREfm originating from nosocomial outbreaks at eight different hospitals in Bavaria were investigated for genetic diversity by WGS. In detail, complex types (CTs) were identified by core-genome MLST. Furthermore, an SNP analysis was performed for all VREfm strains. RESULTS: Most of the isolates of this study (76%) belonged to three major clonal groups, which occurred in at least three hospitals: ST80/CT1065 vanB (n = 45; six hospitals), ST117/CT71 vanB (n = 11; four hospitals) and ST78/CT894like vanA (n = 19; three hospitals). Moreover, isolates of the predominant lineage ST80/CT1065 vanB showed a maximum difference of 36 SNPs as revealed by SNP analysis. CONCLUSIONS: Whole-genome analysis of VREfm causing nosocomial outbreaks suggests the occurrence of few endemic clonal lineages in Bavarian hospital settings, namely ST80/CT1065 vanB, ST117/CT71 vanB and ST78/CT894like vanA. Further studies are needed for a better understanding of the factors affecting the successful spread of the above-mentioned lineages.

Extended-spectrum-ß-lactamase-producing Escherichia coli as intestinal colonizers in the German community.

We determined the presence of extended-spectrum-ß-lactamase (ESBL)-producing Escherichia coli among 3,344 study participants from the German community. Intestinal colonization was detected in 211 persons (6.3%), without significant differences among the different age groups. The majority (95.2%) of isolates harbored CTX-M-type ESBL, with CTX-M-15 (46%) and CTX-M-1 (24.2%) as the most common types. The finding of ESBL producers and one isolate additionally producing carbapenemase OXA-244 indicates a risk of dissemination of resistant bacteria outside the hospitals.

Subgrouping of ESBL-producing Escherichia coli from animal and human sources: an approach to quantify the distribution of ESBL types between different reservoirs.

Escherichia (E.) coli producing extended-spectrum beta-lactamases (ESBLs) are an increasing problem for public health. The success of ESBLs may be due to spread of ESBL-producing bacterial clones, transfer of ESBL gene-carrying plasmids or exchange of ESBL encoding genes on mobile elements. This makes it difficult to identify transmission routes and sources for ESBL-producing bacteria. The objectives of this study were to compare the distribution of genotypic and phenotypic properties of E. coli isolates from different animal and human sources collected in studies in the scope of the national research project RESET. ESBL-producing E. coli from two longitudinal and four cross-sectional studies in broiler, swine and cattle farms, a cross-sectional and a case-control study in humans and diagnostic isolates from humans and animals were used. In the RESET consortium, all laboratories followed harmonized methodologies for antimicrobial susceptibility testing, confirmation of the ESBL phenotype, specific PCR assays for the detection of bla(TEM), bla(CTX), and bla(SHV) genes and sequence analysis of the complete ESBL gene as well as a multiplex PCR for the detection of the four major phylogenetic groups of E. coli. Most ESBL genes were found in both, human and non-human populations but quantitative differences for distinct ESBL-types were detectable. The enzymes CTX-M-1 (63.3% of all animal isolates, 29.3% of all human isolates), CTX-M-15 (17.7% vs. 48.0%) and CTX-M-14 (5.3% vs. 8.7%) were the most common ones. More than 70% of the animal isolates and more than 50% of the human isolates contained the broadly distributed ESBL genes bla(CTX-M-1), bla(CTX-M-15), or the combinations bla(SHV-12)+bla(TEM) or bla(CTX-M-1)+bla(TEM). While the majority of animal isolates carried bla(CTX-M-1) (37.5%) or the combination bla(CTX-M-1)+bla(TEM) (25.8%), this was the case for only 16.7% and 12.6%, respectively, of the human isolates. In contrast, 28.2% of the human isolates carried bla(CTX-M-15) compared to 10.8% of the animal isolates. When grouping data by ESBL types and phylogroups bla(CTX-M-1) genes, mostly combined with phylogroup A or B1, were detected frequently in all settings. In contrast, bla(CTX-M-15) genes common in human and animal populations were mainly combined with phylogroup A, but not with the more virulent phylogroup B2 with the exception of companion animals, where a few isolates were detectable. When E. coli subtype definition included ESBL types, phylogenetic grouping and antimicrobial susceptibility data, the proportion of isolates allocated to common clusters was markedly reduced. Nevertheless, relevant proportions of same subtypes were detected in isolates from the human and livestock and companion animal populations included in this study, suggesting exchange of bacteria or bacterial genes between these populations or a common reservoir. In addition, these results clearly showed that there is some similarity between ESBL genes, and bacterial properties in isolates from the different populations. Finally, our current approach provides good insight into common and population-specific clusters, which can be used as a basis for the selection of ESBL-producing isolates from interesting clusters for further detailed characterizations, e.g. by whole genome sequencing.

Analysis of the effectiveness of hygiene measures and COVID-19 vaccination at a tertiary-care university hospital during the first two years of the SARS-CoV-2 pandemic.

Objective: Assessment of the effectiveness of protective measures at a tertiary-care hospital during the SARS-CoV-2 infection waves to provide advice for future pandemics. Design: Retrospective cohort study among hospital staff using in-house surveillance data. Setting: University Hospital Erlangen (UKER), a tertiary-care provider in Bavaria, Germany. Methods: We outline the preventive measures introduced at UKER and retrospectively assess their effectiveness using anonymized monitoring data that were collected during the SARS-CoV-2 pandemic from February 2020 to the end of January 2022. Analysed data includes the incidence of SARS-CoV-2 infections among employees, the frequency of high-risk contacts with infected patients or staff members and breakthrough infections considering the context of exposure. Results: The cumulative incidence of SARS-CoV-2 infections among UKER employees was higher before, but lower after the vaccination campaign when compared to the general population. Healthcare workers (HCW), notably physicians and nurses, were especially at risk of infection compared to other UKER employees with less direct patient contact (OR 1.36 [95% CI 1.18-1.57 p < 0.001]). Breakthrough infections mostly occurred after exposure during private life, i.e. in situations without protective equipment. The frequency of high-risk contacts during direct patient care remained stable after SARS-CoV-2 vaccination. Prior to vaccination, 5.2% of HCW with direct patient care tested positive for SARS-CoV-2 within 14 days. After vaccination until the onset of the Omicron wave, conversion rate dropped to 0%. Conclusions: This study provides real-world data on the effectiveness of vaccination, contact tracing, personal protective equipment and general hygiene measures during the SARS-CoV-2 pandemic. Based on our findings, we recommend a protective approach combining all these preventive measures.

Emergence of novel ST1299 vanA lineages as possible cause for the striking rise of vancomycin resistance among invasive strains of Enterococcus faecium at a German university hospital.

IMPORTANCE: The proportion of VREfm among all Enterococcus faecium isolated from blood cultures in German hospitals has increased in the period 2015-2020 from 11.9% to 22.3% with a country-wide spread of the clonal lineage ST117/CT71 vanB. In this study, we provided useful information about the genetic diversity of invasive strains of E. faecium. Moreover, our findings confirm the nosocomial spread of novel ST1299 vanA lineages, which recently had a rapid expansion in Austria and the south-eastern part of Germany.

Application of Next-Generation Sequencing to Enterobacter Hormaechei Subspecies Analysis during a Neonatal Intensive Care Unit Outbreak.

INTRODUCTION: The Enterobacter cloacae complex (ECC) species are potential neonatal pathogens, and ECC strains are among the most commonly encountered Enterobacter spp. associated with nosocomial bloodstream infections. Outbreaks caused by ECC can lead to significant morbidity and mortality in susceptible neonates. At the molecular level, ECC exhibits genomic heterogeneity, with six closely related species and subspecies. Genetic variability poses a challenge in accurately identifying outbreaks by determining the clonality of ECC isolates. This difficulty is further compounded by the limitations of the commonly used molecular typing methods, such as pulsed field gel electrophoresis, which do not provide reliable accuracy in distinguishing between ECC strains and can lead to incorrect conclusions. Next-generation sequencing (NGS) offers superior resolution in determining strain relatedness. Therefore, we investigated the clinical pertinence of incorporating NGS into existing bundle measures to enhance patient management during an outbreak of ECC in a level-3 neonatal intensive care unit (NICU) in Germany. METHODS: As the standard of care, all neonates on the NICU received weekly microbiological swabs (nasopharyngeal and rectal) and analysis of endotracheal secretion, where feasible. During the 2.5-month outbreak, colonisation with ECC was detected in n = 10 neonates. The phylogenetic relationship and potential antimicrobial resistance genes as well as mobile genetic elements were identified via bacterial whole-genome sequencing (WGS) using Illumina MiSeq followed by in silico data analysis. RESULTS: Although all ECC isolates exhibited almost identical antimicrobial susceptibility patterns, the WGS data revealed the involvement of four different ECC clones. The isolates could be characterised as Enterobacter hormaechei subspecies steigerwaltii (n = 6, clonal), subsp. hoffmannii (n = 3, two clones) and subsp. oharae (n = 1). Despite the collection of environmental samples, no source of this diffuse outbreak could be identified. A new standardised operating procedure was implemented to enhance the management of neonates colonised with MRGN. This collaborative approach involved both parents and medical professionals and successfully prevented further transmission of ECC. CONCLUSIONS: Initially, it was believed that the NICU outbreak was caused by a single ECC clone due to the similarity in antibiotic resistance. However, our findings show that antibiotic susceptibility patterns can be misleading in investigating outbreaks of multi-drug-resistant ECC. In contrast, bacterial WGS accurately identified ECC at the clonal level, which significantly helped to delineate the nature of the observed outbreak.

Prevalence of methicillin-sensitive, methicillin-resistant Staphylococcus aureus, and extended-spectrum beta-lactamase-producing Escherichia coli in newborns: a cross-sectional study.

BACKGROUND: The prevalence of antimicrobial-resistant bacteria and methicillin-sensitive Staphylococcus aureus (MSSA) in healthy newborns and the role of maternal transmission are scarcely discussed. OBJECTIVES: The objective of this study was to evaluate the prevalence of MSSA, MRSA, and ESBL among healthy newborns. Additionally, mother-to-newborn transmission rates were investigated as well as antibiotic susceptibility of MSSA, MRSA, and ESBL isolates. METHODS: Swabs of 658 newborns and their mothers were collected to investigate the presence of MSSA, MRSA, and ESBL. Swabs were taken from the nose and umbilicus immediately after birth. Additional swabs were taken from the nose, perianal area, and umbilicus 3 days after birth. Samples were screened and further characterized using culture and molecular methods. RESULTS: Prevalence of MSSA, MRSA, and ESBL colonization was 10.9, 0.5, and 2.6%, respectively. There was no association between the colonization status of the newborn and infections at any time point. Mother-to-newborn transmission rates (confirmed by PFGE) were 53.6% for MSSA/MRSA and 100% for ESBL. Maternal carriage of MSSA, MRSA, or ESBL was a risk factor for colonization of the newborn. Some isolates were resistant to the antibiotics recommended for therapy, including clindamycin and daptomycin for MSSA/MRSA isolates and ertapenem, fosfomycin, and tigecyclin for ESBL isolates. CONCLUSION: No association between infections and the newborns' colonization status could be detected. Maternal colonization played an important role in newborn colonization, but not every case of colonization could be explained by mother-to-newborn transmission. General screening of pregnant women and healthy newborns in the absence of other risk factors is not necessary. To prevent the possibility of transmission in the healthcare setting, professionals, pregnant women, parents, hospital visitors, and obstetricians should receive regular training on appropriate hygiene measures. With regard to the emergence of resistance to recommended antibiotics, an antibiogram should be conducted before treating MSSA/MRSA/ESBL infections to ensure the efficacy of the antibiotics.

Resistance to ampicillin, third-generation cephalosporins, ciprofloxacin, co-trimoxazole and azithromycin in clinical isolates of Salmonella enterica subsp. enterica from Germany: real problem or sporadic circumstance?

The objective of this study was to determine the in vitro activity of ampicillin, third-generation cephalosporins, ciprofloxacin, co-trimoxazole and azithromycin against Salmonella enterica isolates. None of the isolates tested showed resistance to third-generation cephalosporins or azithromycin. The rates of resistance to ampicillin, co-trimoxazole and ciprofloxacin were 16.8%, 3.2% and 0.8%, respectively. Moreover, 7.2% of the isolates showed reduced ciprofloxacin susceptibility, but none of them harboured qnr genes. To conclude, our data show that resistance to fluoroquinolones and third-generation cephalosporins in clinical isolates found in Germany still represents a rare circumstance.

First survey of metallo-beta-lactamases in clinical isolates of Pseudomonas aeruginosa in a German university hospital.

A total of 489 clinical isolates of Pseudomonas aeruginosa was investigated for metallo-beta-lactamase (MBL) production. Molecular analysis detected a blaVIM-1 gene in the chromosome of one isolate and a blaVIM-2 gene carried on the plasmid in seven isolates. Moreover, we showed that an initial screening by combined susceptibility testing of imipenem and ceftazidime followed by a confirmatory EDTA combination disk test represents a valid alternative to the molecular investigation of MBL genes, making MBL detection possible in routine diagnostic laboratories.

Antimicrobial susceptibility of clinical Campylobacter isolates collected at a German university hospital during the period 2006-2008.

A total of 113 clinical Campylobacter strains (105 C. jejuni, 7 C. coli, 1 C. lari) were collected between 2006 and 2008 and tested for antimicrobial susceptibility to erythromycin, ciprofloxacin, doxycycline and meropenem. Of all the Campylobacter isolates, 52.2% were resistant to ciprofloxacin and 38.0% to doxycycline. None of them was resistant to erythromycin or meropenem. However, 51.3% of all Campylobacter isolates were intermediate susceptible to erythromycin (minimum inhibitory concentration 1-4 mg/l). These data confirm the value of macrolides as the drugs of choice for the treatment of severe Campylobacter infections.

Resistance to tobramycin and colistin in isolates of Pseudomonas aeruginosa from chronically colonized patients with cystic fibrosis under antimicrobial treatment.

Tobramycin and colistin represent 2 standard antimicrobial agents in the treatment of cystic fibrosis (CF) patients who are chronically colonized with Pseudomonas aeruginosa. In this study, we determined the rate of resistance to tobramycin and colistin in 1844 isolates of P. aeruginosa obtained from 22 CF patients under alternate therapy with inhaled tobramycin and colistin. Resistance to tobramycin was observed in 27.5% of isolates. In contrast, all isolates were susceptible to colistin. Molecular typing of selected isolates suggested that only 1 clone occurred over time in each patient. To conclude, resistance to tobramycin in P. aeruginosa isolates from CF patients under antimicrobial therapy may occur while colistin resistance remains uncommon.

Microbial changes in periodontitis successfully treated by mechanical plaque removal and systemic amoxicillin and metronidazole.

Scaling and root planing in conjunction with systemic administration of antibiotics is used for treatment of aggressive periodontitis. The study investigated the changes of the subgingival microbiota in a homogeneous cohort of 12 female Caucasian patients. Plaque samples were obtained from 4 defined deep lesions per patient at baseline and 2, 6, and 12 months after therapy (mechanical plaque removal, oral administration of amoxicillin and metronidazole). Amplification of the 16S rRNA gene, cloning, and sequencing were applied to identify microbial species. Porphyromonas gingivalis strains were typed by multilocus sequence typing. Despite of a favorable clinical outcome, 16S rRNA sequence analysis revealed only minor changes of the microbiota with a temporal reduction of P. gingivalis and of Treponema denticola-like phylotypes. In contrast to T. denticola, T. sokranskii-like phylotypes were not affected. In 4 patients with recurrent colonization by P. gingivalis, the bacterial clones were identical before and after therapy as evidenced by multilocus sequence typing suggesting clonal persistence or reinfection during the course of the study. In summary, despite a favorable clinical outcome, a transient effect on only few bacterial species was observed.

First report of the new emerging global clone ST1193 among clinical isolates of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli from Germany.

OBJECTIVES: Sequence type 1193 (ST1193) is a new emerging global clone of Escherichia coli. The main goal of this study was to determine the prevalence and molecular characteristics of ST1193 among clinical isolates of extended-spectrum ß-lactamase (ESBL)-producing E. coli from University Hospital of Erlangen, Germany. METHODS: Between November 2015 and February 2016, all consecutive non-duplicate clinical E. coli isolates showing resistance to cefotaxime or ceftazidime were further analysed for ESBL production by the combined disk method. ESBL genes were identified by PCR and sequencing. Bacterial strain typing was performed by PCR-based phylogrouping, MLST and whole-genome sequencing. RESULTS: ESBL production was confirmed in 51 isolates. The globally dominant ST131 occurred at a frequency of 37.3% (n=19). Major non-ST131 sequence types were ST38 (n=4; 7.8%), ST10 (n=3; 5.9%) and ST1193 (n=3; 5.9%). Among the ESBL-producing E. coli ST1193, two expressed CTX-M-14 and one expressed CTX-M-15 ESBL type. All three ST1193 isolates belonged to serogroup O75:H5, phylogroup B2, and harboured IncFIA and IncFIB plasmids and the virulence factors genes iha, sat, gad, vat and senB. Moreover, they showed ciprofloxacin resistance and exhibited a set of four conserved mutations defining quinolone resistance (gyrA S83L, gyrA D87N, parC S80I and parC L416F). CONCLUSIONS: This study revealed for the first time in Germany the occurrence of ST1193 among clinical isolates of ESBL-producing E. coli. Further national or regional multicentre studies are needed to assess the effective relevance of ESBL-producing E. coli ST1193 as a nosocomial pathogen in Germany.

Evaluation of new colorimetric vitek 2 yeast identification card by use of different source media.

The new colorimetric Vitek 2 YST card was evaluated for identification of yeasts (136 strains) with respect to the influence of different source media. The Vitek 2 YST card achieved satisfactory results for all yeast species tested, with the exception of Candida guilliermondii, Candida norvegensis, Candida parapsilosis, Candida rugosa, and Candida tropicalis. After simple additional tests, 93.7% of all the strains tested were correctly identified. A significant influence of the isolation medium on the identification rate could not be observed.

Prevalence and antimicrobial susceptibility of microorganisms isolated from sputa of patients with cystic fibrosis.

BACKGROUND: New emerging pathogens and associated antimicrobial resistance mechanisms have been observed in the respiratory tract of patients suffering from cystic fibrosis (CF) in the last years. Amongst others, the rate of metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa strains is growing. However, there are no published data on the prevalence of MBL-producing P. aeruginosa in CF patients to our knowledge. METHODS: In this study, 271 sputum samples of 60 CF patients were collected during a 12-months period. Microbiological cultures and antimicrobial susceptibility tests of the most frequently isolated bacteria were performed. RESULTS: 464 bacterial and 414 fungal strains were isolated and characterized. 63.3% of the patients harbored Staphylococcus aureus, 50% P. aeruginosa, 16.6% Haemophilus influenzae, 15% Stenotrophomonas maltophilia and 13.3% non tuberculous Mycobacteria (NTM). Methicillin resistant S. aureus (MRSA) and MBL-producing P. aeruginosa were detected in 3 (5%) and 5 (8.3%) patients respectively. Among the fungi, Aspergillus fumigatus and Candida albicans showed the highest prevalence. CONCLUSIONS: The detection of MBL-producing P. aeruginosa and MRSA in CF patients confirms that antimicrobial resistance patterns should be always kept under surveillance. Moreover hygiene regulations in CF clinics should prevent a further spread of resistant bacterial strains.

Molecular Characterization of Extended-Spectrum ß-Lactamase-Producing Escherichia coli Isolates from Milk Samples of Dairy Cows with Mastitis in Bavaria, Germany.

The aim of this study was to determine the rate of extended-spectrum ß-lactamase (ESBL)-producing microorganisms among Escherichia coli isolates causing bovine mastitis, including molecular characterization of these isolates. Therefore, a total of 490 bovine E. coli isolates from milk samples of dairy cows with mastitis were investigated for ESBL production by antimicrobial susceptibility testing, PCR-based detection, and sequencing of ESBL encoding genes, which were identified in 22 isolates (4.5%). Moreover, resistance to the fluoroquinolones enrofloxacin and marbofloxacin occurred in 15 of 22 ESBL-producing isolates (68.2%). All ESBL-producing isolates carried a blaCTX-M-like gene, with blaCTX-M-14 (n = 10) as the most prevalent type. Seven isolates producing CTX-M-14 and belonging to phylogenetic group A were further investigated for genetic relatedness by multilocus sequence typing. Five of them could be assigned to four different sequence types (STs): ST10 (n = 2), ST167 (n = 1), ST410 (n = 1), and ST744 (n = 1), whereas the remaining two isolates could not be assigned. To conclude, the rate of ESBL-producing E. coli associated with cattle mastitis was 4.5%. Furthermore, a high proportion of fluoroquinolone coresistance could be detected. Therefore, careful and continuous surveillance of ESBL-producing E. coli in cattle and consequent implementation of prevention measures are needed to avoid a further spread of these multidrug-resistant bacteria.

Prevalence and genetic diversity of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli in nursing homes in Bavaria, Germany.

Main goal of this study was to determine the prevalence and molecular epidemiology of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae among 156 nursing home residents in Bavaria and to compare the results with healthy individuals from the Bavarian community. Intestinal colonisation by ESBL-producing Escherichia coli was detected in 23 nursing home residents (14.7%) using MacConkey agar supplemented with cefotaxime (1mg/L) for screening and the combined disc method for ESBL confirmation. Antimicrobial susceptibility testing revealed co-resistance to ciprofloxacin in 86.9% of the ESBL-producers. All isolates harboured CTX-M-ESBL with CTX-M-15 (65.2%) and CTX-M-27 (21.7%) as the most common types. Moreover, 16 isolates (69.6%) could be assigned by PCR-typing to the epidemic clonal lineage E. coli O25b-ST131. Further typing by rep-PCR and XbaI-macrorestriction with subsequent pulsed-field gel electrophoresis, respectively, revealed that two or more residents shared the same ESBL-producing E. coli clone in four nursing homes. In conclusion, we could show a high prevalence of ESBL-producing E. coli in Bavarian nursing homes (14.7%) compared to the healthy population (6.3%). Although the prevalence of ESBL-type CTX-M-15 in E. coli was similar in nursing home residents (65.2%) and healthy individuals (46%) the presence of E. coli O25b-ST131 clones differed substantially (69.6% and 14.2%, respectively). Furthermore, this study demonstrates that a person-to-person transmission or a common source of infection for ESBL-producing microorganisms may occur in these facilities. Therefore, basic hygiene measures should be assiduously implemented to prevent the further spread of these multidrug-resistant bacteria.

Screening of ESBL-producing Enterobacteriacae concomitant with low degree of transmission in intensive care and bone marrow transplant units.

BACKGROUND: Extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E) are spreading worldwide in both hospital and community settings. In this study, the molecular epidemiology and the transmission modalities of ESBL-E in intensive care- and bone marrow transplant were investigated. METHODS: All patients included in this study were screened for presence of ESBL-E on admission and weekly. Relevant ß-lactamase genes were identified by PCR and sequencing. RESULTS: A total of 669 patients were included in this study. On admission, ESBL-producing Escherichia coli were detected in 49 (7.3%) patients and ESBL-producing Klebsiella pneumoniae in one patient. The most common ESBL types among E. coli isolates were CTX-M-15 (38.8%) and CTX-M-1 (38.8%). Furthermore, 12 of 49 (24.5%) ESBL-producing E. coli could be assigned to the epidemic clone ST131. A single patient acquired ESBL-producing E. coli during the hospital stay but cross-transmission could not be demonstrated. Among 1095 environmental samples none revealed ESBL. CONCLUSIONS: Our results suggest that early detection of ESBL-producing Enterobacteriaceae and consequent implementation of basic hygiene measures and contact isolation may reduce the transmission rate during the hospital stay.