Surveillance of extended-spectrum β-lactamase-producing bacteria and routine use of contact isolation: experience from a three-year period

Beta-lactamase genes in bacteria from food animals, retail meat, and human surveillance programs in the United States from 2002 to 2021

The spread of beta-lactamase-producing bacteria is a global public-health concern. This study aimed to explore the distribution of beta-lactamases reported in three sampling sources (cecal, retail meat, and human) collected as part of integrated surveillance in the United States. We retrieved and analyzed data from the United States National Antimicrobial Resistance Monitoring Systems (NARMS) from 2002 to 2021. A total of 115 beta-lactamase genes were detected in E. coli, Salmonella enterica, Campylobacter, Shigella and Vibrio: including 35 genes from cecal isolates, 32 genes from the retail meat isolates, and 104 genes from the human isolates. Three genes in E. coli (blaCMY-2,blaTEM-1A, and blaTEM-1B), 6 genes in Salmonella enterica (blaCARB-2, blaCMY-2, blaCTXM-65, blaTEM-1A, blaTEM-1B, and blaHERA-3), and 2 genes in Campylobacter spp. (blaOXA-61 and blaOXA-449) have been detected across food animals (cattle, chicken, swine, and turkey) and humans over the study period. blaCTXM-55 has been detected in E. coli isolates from the four food animal sources while blaCTXM-15 and blaCTXM-27 were found only in cattle and swine. In Salmonella enterica, blaCTXM-2, blaCTXM-9, blaCTXM-14, blaCTXM-15, blaCTXM-27, blaCTXM-55, and blaNDM-1 were only detected among human isolates. blaOXAs and blaCARB were bacteria-specific and the only beta-lactamase genes detected in Campylobacter spp. and Vibrio spp respectively. The proportions of beta-lactamase genes detected varies from bacteria to bacteria. This study provided insights on the beta-lactamase genes detected in bacteria in food animals and humans in the United States. This is necessary for better understanding the molecular epidemiology of clinically important beta-lactamases in one health interface.

Fecal carriage of extended-spectrum β-lactamase-producing enterobacterales from hospitals and community settings in Gaza Strip, Palestine

BACKGROUND

The fecal carriage of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PE) is a major driver of the global spread of these antibiotic resistance determinants. Here we determined the rate of fecal ESBL-PE carriage in pediatric hospitals and community-serving healthcare centers serving adults and children in the Gaza Strip, Palestine.

METHODS

A total of 373 fecal and rectal samples were collected from different hospitals and clinics in Gaza. The antibiotic susceptibility was determined using the disk diffusion method and interpreted according to CLSI guidelines. The bacterial isolates were tested for ESBL production using phenotypic methods (double disk synergy test and growth on selective chromogenic media). BlaCTX-M, blaSHV, and blaTEM genes were sought by PCR.

RESULTS

Out of the 373 isolates tested, 138 (37%) were considered ESBL positive as revealed by phenotypic tests. The prevalence of ESBLs among hospitalized patients was 39.1% (hospital setting) whereas, among outpatients attending community healthcare centers, it was 35.1% (community setting). ESBL production among Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Proteus mirabilis, and Klebsiella aerogenes isolates was 52.8%, 39.1%, 26.7%, 2.8%, and 2.1% respectively. Meropenem and amikacin were the most effective antibiotics against ESBL producers (68.9% and 73.6% susceptibility, respectively), while only 15.2%, 22.5%, and 24.6% remained susceptible to ceftazidime, cefotaxime, and ceftriaxone, respectively. Out of 138 phenotypically ESBL-positive isolates, 98 randomly chosen were screened for blaCTX-M, blaTEM, and blaSHV genes. The prevalence rate of blaCTX-M was 45.9%, while blaTEM and blaSHV genes were detected in 16.8% and 5.2% of CTX-M-negative isolates (corresponding mostly for K. pneumoniae isolates in the case of SHV-PCR), respectively.

CONCLUSIONS

The study revealed an alarmingly high prevalence of fecal carriage of ESBL-producing Enterobacterales among hospitalized children but also in the community of the Gaza Strip. In addition, 30% of ESBL-producers were already resistant to carbapenems, the treatment of choice of infections with ESBL-producers.

Predictive value of surveillance cultures for bacteremia caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales among patients with hematological diseases

PURPOSE

Due to the increasing prevalence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales, empirical therapies with cefepime or piperacillin/tazobactam for hematology patients with febrile neutropenia have become ineffective. Carbapenems should be administered as soon as possible in such patients with ESBL bacteremia. If the surveillance culture results are consistent with the blood culture findings, the time to adequate treatment initiation can be shortened.

METHODS

All consecutive patients with Enterobacterales bacteraemia who were admitted from January 2013 to December 2018 at the hematology wards were enrolled in this study. Surveillance rectal swab and blood culture results were compared.

RESULTS

In total, 67 patients with Enterobacterales bacteremia underwent surveillance culture prior to the onset of infection. Regarding the presence or absence of ESBL-producing Enterobacterales, 64 (95.5%) patients had surveillance results concordant with blood culture results. The positive predictive value of surveillance culture for bacteremia caused by ESBL-producing Enterobacterales was 95.0%. Moreover, the negative predictive value of surveillance culture for bacteremia caused by non-ESBL-producing Enterobacterales was 95.7%.

CONCLUSION

The concordance rate between the surveillance rectal swab and blood cultures was highly acceptable. Surveillance rectal swab cultures are useful for identifying patients at high risk for ESBL bacteremia.

Detailed epidemiological analysis as a strategy for evaluating the actual behavior of tuberculosis in an apparently low-incidence region

Tuberculosis control in developing regions with apparent low incidence, like the low-income Mexican state of Michoacán, with mean annual incidence rates below 10/100,000 inhabitants, requires knowledge of the actual behavior of the disease. This can be determined using an epidemiological profile at sub-regional level, allowing disclosure of the clinical and social factors that may be hampering efforts to control tuberculosis. In this work, a detailed epidemiological profile was outlined using data of all new monthly cases registered in the National System of Epidemiological Surveillance Database for Michoacán municipalities from 2000 to 2012. Cases were grouped by gender and age, and sociodemographic data were obtained both from the National Institute of Statistics and Geography and from the United Nations Development Programme. Correlations were calculated by Chi-square, Mann-Whitney U, and Kruskal-Wallis H tests. We observed no statistically significant differences between notification rates for the years 2000, 2005 and 2010 (χ² = 0.222, p = 0.895). The percentage of cases is similar between all age groups older than 15, while some regions had low notification rates but high proportions of pediatric cases. Higher proportions of cases of extrapulmonary tuberculosis were observed in municipalities in northern Michoacán. No correlation was found between municipal Human Development Index values and municipal notification rates. Michoacán is undergoing an epidemiological transition with three regions having different epidemiological profiles and particular needs for effective prevention and containment of tuberculosis. Our work shows the importance of the spatial scale of epidemiological profiles for determining specific regional needs of surveillance and containment.

Depression and anxiety in hospitalized patients on contact precautions for multidrug-resistant microorganisms

BACKGROUND

Contact precautions for patients with multidrug-resistant organisms (MDROs) have been associated with adverse effects. The aim of this study was, therefore, to evaluate the level of anxiety and depression through different standardized scales in patients isolated by MDROs.

METHODS

This is a case-control study with hospitalized patients on contact precautions for MDROs. A questionnaire survey was conducted to analyse the presence and level of depression and anxiety. A multivariable analysis was performed to define independent questions for anxiety/depression scores to create a short questionnaire facilitating a practical approach to the care of hospitalized patients with MDROs. A receiver operating characteristic (ROC) curve was plotted to determine the diagnostic ability of the simplified score.

RESULTS

A total of 141 patients were included in the study, among whom 68 were isolated because of MDRO colonization while 73 were not isolated (control-group). Forty-five (31.9%) patients had some degree of anxiety. Patients in MDRO contact isolation had a higher level of anxiety than those who were not isolated (55.9% vs. 9.6%, p < 0.001). The equation obtained by multivariated analysis allowed for the construction of a score with ROC area of 0.949 and a sensitivity of 91.1%.

CONCLUSION

Contact isolation for MDROs is associated with increased depression and anxiety. A simple anxiety score was developed and should be validated for screening.

Dutch guideline for preventing nosocomial transmission of highly-resistant micro-organisms (HRMO) in long-term care facilities (LTCFs)

In 2012, the Dutch Working Party for Infection Control (WIP) issued the first Guideline for prevention of transmission of highly-resistant micro-organisms (HRMO) in Hospitals. The next step was to focus on long-term care facilities (LTCFs) both for nursing homes as for small-scale living facilities with nursing home care. These facilities providing care for residents with functional disabilities, chronical illnesses and cognitive disorders, such as dementia. The objective was to adapt the Guideline for prevention of transmission of HRMO in hospitals to LTCFs with a strong accent on living conditions and social interactions.

Residents of LTCFs may be carriers of HRMO over a long period of time and most of the residents of the LTCF stay for extended periods of time. To respect individual living circumstances and to prevent unnecessary limitations in the social life of the residents due to the use of isolation measures, the WIP has chosen to describe infection control precautions per individual micro-organism instead of a ‘one size fits all’ method. The term “isolation” was therefore replaced by the term “additional” precautions. This guideline describes the screening policies for residents in LTCFs, definition and detection of HRMO carriage, standard and additional infection control precautions for HRMO positive residents, documentation and communication of HRMO carriage and discontinuation of additional infection control precautions. It also describes contact tracing of HRMO, environmental control/investigation, surveillance of HRMO and what is important when there is an outbreak.

Molecular typing of cytotoxin-producing Klebsiella oxytoca isolates by 16S-23S internal transcribed spacer PCR

Cytotoxin is one of the important pathogenic factors, which plays a role in the virulence of Klebsiella oxytoca. The aim of this study was to investigate molecular typing of clinical isolates of the cytotoxin-producing K. oxytoca using internal transcribed spacer (ITS) PCR. A total of 75 isolates of K. oxytoca were isolated from clinical samples; they were verified as K. oxytoca by standard microbiological tests and PCR. Production of toxin determines the cytotoxic effects on HEp-2 cells. The genetic diversity of isolates of the cytotoxin-producing K. oxytoca were defined by ITS-PCR. Of all the isolates investigated, five K. oxytoca strains isolated from stool cultures, two strains from blood samples, one strain from a wound and one strain isolated from urine had cytotoxic effects on HEp-2 cells. The ITS-PCR patterns showed genetic diversity among cytotoxin-producing isolates. The ITS-PCR method had good discriminatory power; performance of this method and interpretation of the results were easy and repeatable. Five genetic diversity patterns were identified by ITS-PCR.

Multidrug-Resistant Gram-Negative Bacilli: A Retrospective Study of Trends in a Tertiary Healthcare Unit

Background and objective: Bacterial multidrug resistance is particularly common in Gram-negative bacilli (GNB), with important clinical consequences regarding their spread and treatment options. The aim of this study was to investigate the trend of multidrug-resistant GNB (MDR-GNB) in high-risk hospital departments, between 2000–2015, in intervals of five years, with the intention of improving antibiotic therapy policies and optimising preventive and control practices. Materials and methods: This is an observational, retrospective study performed in three departments of the most important tertiary healthcare unit in the southwestern part of Romania: the Intensive Care Unit (ICU), the General Surgery Department (GSD), and the Nutrition and Metabolic Diseases Department (NMDD). MDR was defined as acquired resistance to at least one agent in three or more antimicrobial categories. Trends over time were determined by the Cochran–Armitage trend test and linear regression. Results: During the study period, a total of 2531 strains of MDR-GNB were isolated in 1999 patients: 9.20% in 2000, 18.61% in 2005, 37.02% in 2010, and 35.17% in 2015. The most significant increasing trend was recorded in the ICU (gradient = 7.63, R² = 0.842, p < 0.001). The most common MDR-GNB in the ICU was isolated from bronchoalveolar aspiration samples. Concerning the proportion of different species, most of the changes were recorded in the ICU, where a statistically significant increasing trend was observed for Proteus mirabilis (gradient = 2.62, R² = 0.558, p < 0.001) and Acinetobacter baumannii (gradient = 2.25, R² = 0.491, p < 0.001). Analysis of the incidence of the main resistance phenotypes proportion identified a statistically significant increase in carbapenem resistance in the ICU (Gradient = 8.27, R² = 0.866, p < 0.001), and an increased proportion of aminoglycoside-resistant strains in all three departments, but more importantly in the ICU and GSD. Conclusion: A statistically significant increasing trend was observed in all three departments; the most significant one was recorded in the ICU, where after 2010, carbapenem-resistant strains were isolated.

Third-generation-cephalosporin-resistant Klebsiella pneumoniae isolates from humans and companion animals in Switzerland: spread of a DHA-producing sequence type 11 clone in a veterinary setting

Characterization of third-generation-cephalosporin-resistant Klebsiella pneumoniae isolates originating mainly from one human hospital (n = 22) and one companion animal hospital (n = 25) in Bern (Switzerland) revealed the absence of epidemiological links between human and animal isolates. Human infections were not associated with the spread of any specific clone, while the majority of animal infections were due to K. pneumoniae sequence type 11 isolates producing plasmidic DHA AmpC. This clonal dissemination within the veterinary hospital emphasizes the need for effective infection control practices.

Prevalence and genotypes of extended spectrum beta-lactamases in Enterobacteriaceae isolated from human stool and chicken meat in Hamburg, Germany

Chicken meat has been proposed to constitute a source for extended spectrum beta-lactamase (ESBL)-carrying Enterobacteriaceae that colonize and infect humans. In this study the prevalence of ESBL-producing Enterobacteriaceae in stool samples from ambulatory patients who presented in the emergency department of the University Medical Centre Hamburg-Eppendorf with gastrointestinal complains and in chicken meat samples from the Hamburg region were analysed and compared with respect to ESBL-genotypes, sequence types and antibiotic resistance profiles. Twenty-nine (4.1%) of 707 stool samples and 72 (60%) of 120 chicken meat samples were positive for ESBL-producing Enterobacteriaceae. The distribution of ESBL genes in the stool vs. chicken meat isolates (given as % of total isolates from stool vs. chicken meat) was as follows: CTX-M-15 (38% vs. 0%), CTX-M-14 (17% vs. 6%), CTX-M-1 (17% vs. 69%), SHV-12 (3% vs. 18%) and TEM-52 (3% each). Comparison of ESBL- and multilocus sequence type revealed no correlation between isolates of human and chicken. Furthermore, ESBL-producing E. coli from stool samples were significantly more resistant to fluoroquinolones, aminoglycosides and/or trimethoprim-sulfamethoxazole than chicken isolates. The differences in ESBL-genotypes, sequence types and antibiotic resistance patterns indicate that in our clinical setting chicken meat is not a major contributor to human colonization with ESBL-carrying Enterobacteriaceae.

[Impact of enterobacteriaceae-producing extended-spectrum beta-lactamases (ESBLE) incidence increasing on barrier precautions implementation in a university hospital]

AIM OF THE STUDY

The French national surveillance program of multidrug-resistant bacteria (MDR) shows an increase of enterobacteriaceae-producing extended-spectrum beta-lactamases (ESBLE) incidence. The objectives of this study were to assess: the incidence of EBLSE in a large French university hospital between 2005 and 2010, and the difference of barrier precautions implementation between ESBL and other MDR.

METHODS

The ESBLE incidence measure used data from the laboratory of bacteriology. The application of isolation and barrier precautions was analyzed from the MRB national surveillance data over a 3-year period from 2006 to 2008. Data were entered and analyzed using Epi Info software. The Chi(2) test was used for the comparison of proportions.

RESULTS

The overall incidence of ESBLE was significantly higher in 2010 than in 2005 (0.20/1000 patients-days vs 0.03/1000 patients-days, respectively) (P<0.001). The same was observed for Escherichia coli incidence with rates ranging from 0.02/1000 patients-days in 2005 to 0.15/1000 patients-days in 2010. Isolation precautions for patients with EBLSE were applied in relation for most patients with MRB (ESBLE vs others), without significant difference.

CONCLUSION

The surveillance programme of MRB showed a significant increase of ESBLE, especially for E. coli. Isolation and barrier precautions were used for most patients with MRB, including ESBLE.

Prevalence of extended-spectrum beta-lactamase-producing Enterobacteriaceae in healthy Swedish preschool children

AIM

The objective was to determine the prevalence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in faeces from healthy Swedish preschool children and to establish whether transmission took place between children in preschools.

METHODS

Diapers from children attending preschools in Uppsala city were collected during September to October 2010, and the faeces was cultured. Antibiotic profiles and carriage of CTX-M, TEM, SHV and AmpC type enzymes were determined. PCR-positive isolates were further characterized by sequencing and epidemiological typing. Statistics on antibiotic use and ESBL producers in paediatric patients at Uppsala University Hospital were extracted for comparison.

RESULTS

A total of 313 stool specimens were obtained, representing 24.5% of all preschool children in Uppsala city. The carriage rate of ESBL-producing Enterobacteriaceae was 2.9% among these healthy children. The corresponding figure for patients in the same age group was 8.4%. Escherichia coli with CTX-M type enzymes predominated, and only one E. coli isolate carried genes-encoding CMY. CTX-M-producing E. coli isolates with identical genotypes were found in children with no familial relation at two different preschools.

CONCLUSIONS

Using diapers, the prevalence of ESBL-producing Enterobacteriaceae in children was quickly established, and, most likely, a transmission of ESBL-producing E. coli was for the first time documented between children at the same preschool.

Outbreak of extended-spectrum β-lactamase-producing Klebsiella oxytoca infections associated with contaminated handwashing sinks(1)

Sinks are a potential reservoir for environment-to-patient and patient-to-patient transmission.

Klebsiella oxytoca is primarily a health care–associated pathogen acquired from environmental sources. During October 2006–March 2011, a total of 66 patients in a hospital in Toronto, Ontario, Canada, acquired class A extended-spectrum β-lactamase–producing K. oxytoca with 1 of 2 related pulsed-field gel electrophoresis patterns. New cases continued to occur despite reinforcement of infection control practices, prevalence screening, and contact precautions for colonized/infected patients. Cultures from handwashing sinks in the intensive care unit yielded K. oxytoca with identical pulsed-field gel electrophoresis patterns to cultures from the clinical cases. No infections occurred after implementation of sink cleaning 3×/day, sink drain modifications, and an antimicrobial stewardship program. In contrast, a cluster of 4 patients infected with K. oxytoca in a geographically distant medical ward without contaminated sinks was contained with implementation of active screening and contact precautions. Sinks should be considered potential reservoirs for clusters of infection caused by K. oxytoca.

[Enterobacteriaceae producing extended spectrum beta-lactamase: epidemiology, risk factors, and prevention]

Multidrug-resistant bacteria are a major worldwide health public concern. It results from the growing increase in antibiotic prescriptions, which are responsible for selection pressure on bacteria. In France like in other countries, enterobacteriaceae producing extended spectrum beta-lactamase (EESBL) are the predominant multidrug-resistant bacteria. EESBL may be responsible for severe infections and require prescription of broad-spectrum antibacterial agents. The current EESBL outbreak is different from methicillin-resistant Staphylococcus aureus outbreak that occurred in the early 1980. Consistently, EESBL are isolated both in hospital and community. Moreover, standard hygiene measures appear ineffective since EESBL prevalence is still increasing. The current inability to contain EESBL outbreak is due to several factors, including the existence of a wide community- and hospital-acquired tank of EESBL, failure to follow strict rules for hygiene, and the current irrational prescription of antibiotics.

The role of horizontal gene transfer in the dissemination of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates in an endemic setting

The contribution of horizontal gene transmission (HGT) in the emergence and spread of extended-spectrum beta-lactamase (ESBL)-producing Gram-negative bacteria during periods of endemicity is unclear. Over a 12-month period, rectal colonization with SHV-5- and SHV-12-producing Escherichia coli and Klebsiella pneumoniae was quantified among a cohort of residents in a long-term care facility. Demographic and clinical data were collected on colonized residents. Transferability of SHV-encoding plasmids and pulsed-field gel electrophoresis were performed to quantify the contribution of HGT and cross-transmission, respectively. A total of 25 (12%) of 214 enrolled patients were colonized with 11 SHV-5- and 17 SVH-12-producing E. coli and K. pneumoniae. Clonally related isolates were detected among multiple residents residing on the same and different wards. Among 12 clonally distinct isolates, HGT of SHV-5- and SHV-12-encoding plasmids was identified among 6 (50%) isolates. HGT among clonally distinct strains contributes to the transmission dynamics of these ESBL-producing Gram-negative bacteria and should be considered when evaluating the spread of these pathogens.

Transmission dynamics of extended-spectrum β-lactamase-producing Enterobacteriaceae in the tertiary care hospital and the household setting

Transmission of extended-spectrum β-lactamase (ESBL)–producing Enterobacteriaceae in households outweighs nosocomial dissemination in the non-outbreak setting. Importation of ESBL producers into the hospitals is as frequent as transmission during hospital stay. ESBL–Klebsiella pneumoniae might be more efficiently transmitted within the hospital than ESBL–Escherichia coli.

Background. Studies about transmission rates of extended-spectrum β-lactamase (ESBL)–producing Enterobacteriaceae in hospitals and households are scarce.

Methods. Eighty-two index patients with new carriage of ESBL-producing Escherichia coli (ESBL-Ec; n = 72) or ESBL-producing Klebsiella pneumoniae (ESBL-Kp; n = 10) and their hospital (n = 112) and household (n = 96) contacts were studied prospectively from May 2008 through September 2010. Isolates were phenotypically and molecularly characterized (sequencing of bla genes, repetitive extragenic palindromic polymerase chain reaction, pulse-field gel electrophoresis, and multilocus sequence typing). Transmission was defined as carriage of a clonally-related ESBL producer with identical bla_ESBL gene(s) in the index patient and his or her contact(s).

Results. CTX-M-15 was the most prevalent ESBL in ESBL-Ec (58%) and ESBL-Kp (70%) in the index patients. Twenty (28%) ESBL-Ec isolates were of the hyperepidemic clone ST131. In the hospital, transmission rates were 4.5% (ESBL-Ec) and 8.3% (ESBL-Kp) and the incidences of transmissions were 5.6 (Ec) and 13.9 (Kp) per 1000 exposure days, respectively. Incidence of ESBL-Kp hospital transmission was significantly higher than that of ESBL-Ec (P < .0001), despite implementation of infection control measures in 75% of ESBL-Kp index patients but only 22% of ESBL-Ec index patients. Detection of ESBL producers not linked to an index patient was as frequent (ESBL-Ec, 5.7%; ESBL-Kp, 16.7%) as nosocomial transmission events. In households, transmission rates were 23% for ESBL-Ec and 25% for ESBL-Kp.

Conclusions. Household outweighs nosocomial transmission of ESBL producers. The effect of hospital infection control measures may differ between different species and clones of ESBL producers.

Duration of colonization with extended-spectrum beta-lactamase-producing Escherichia coli in patients with travellers' diarrhoea

BACKGROUND

Resistant Enterobacteriaceae have become a worldwide epidemic during the last decade and are a great threat to health care worldwide. International travel is a major risk factor for becoming colonized with extended-spectrum beta-lactamase (ESBL)-producing bacteria. Data on the persistence of colonization with ESBL-producing bacteria in the faecal flora are limited.

METHODS

A prospective cohort study was performed between October 2007 and October 2010. Fifty-eight patients with faecal carriage of ESBL-producing Escherichia coli from a previous study of patients with travellers' diarrhoea were included.

RESULTS

Forty-one of the patients had a complete follow-up. Ten of these patients (24%) carried ESBL-producing E. coli at the first follow-up point (3-8 months), of whom 4 had a new ESBL strain. At the 3-y follow-up, 4 patients carried ESBL (10%), of whom 1 had 2 new ESBL strains.

CONCLUSIONS

The long duration of ESBL carriage is worrisome. These carriers may be an important source of the spread of ESBLs in the population and this has implications for the clinical management of patients.

Faecal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae among humans in Java, Indonesia, in 2001-2002

OBJECTIVE

To characterise commensal Escherichia coli and other Enterobacteriaceae with reduced susceptibility to cefotaxime that were collected in a large survey carried out among 3995 patients and healthy persons in two urban regions on Java, Indonesia, in 2001-2002.

METHODS

The putative extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae were analysed using double-disk synergy tests, isoelectric focusing, PCR assays, DNA sequencing, and pulsed-field gel electrophoresis (PFGE).

RESULTS

On the day of discharge after five or more days of hospitalisation, at least 95 of 999 (9.5%) patients carried ESBL-positive Enterobacteriaceae as dominant faecal flora. Six patients were simultaneously colonised with E. coli and Klebsiella pneumoniae isolates with ESBL activity. On admission, only 6 of 998 (0.6%) patients were colonised. Faecal carriage of ESBL-producing Enterobacteriaceae among healthy persons or persons visiting a public health centre was not detected. The 107 ESBL-positive strains included 68 E. coli, 35 K. pneumoniae, and four other Enterobacteriaceae. bla(CTX-M-15) was the most prevalent ESBL in both E. coli (47.1%) and K. pneumoniae (45.7%), but the E. coli O25b-ST131 clone was virtually absent. Other ESBL types found were: SHV-2, -2a, -5, -12, CTX-M-3, -9, -14, and TEM-19. PFGE revealed extensive genetic diversity among the isolates.

CONCLUSIONS

In 2001-2002, faecal carriage of ESBL-producing Enterobacteriaceae as dominant flora in Indonesia was almost exclusively hospital-associated. The presence of various bla(ESBL) genes and the extensive genetic diversity among isolates argue against a single/dominant strain outbreak.

Preventing the spread of multidrug-resistant gram-negative pathogens: recommendations of an expert panel of the German Society For Hygiene and Microbiology

BACKGROUND

Infections with multidrug-resistant gram-negative bacteria are hard to treat and cause high morbidity and mortality. The direct transmission of such pathogens is well documented, and measures to protect other patients would seem indicated. Nonetheless, evidence-based recommendations are not yet available because of insufficient data from clinical trials.

METHODS

An expert panel was convened by two sections of the German Society for Hygiene and Microbiology (the permanent committee on general and hospital hygiene and the special committee on infection prevention and antibiotic resistance in hospitals) to review existing data on the epidemiology and diagnostic evaluation of multidrug-resistant gram-negative pathogens. The panel carried out a selective review of the relevant literature, with special attention to national guidelines.

RESULTS AND CONCLUSION

In this paper, the expert panel presents a definition of multidrug-resistant gram-negative pathogens and recommends measures for presenting the spread of infection from colonized and infected patients in non-outbreak situations. These measures depend on the risk profile of the clinical setting. They are mostly to be considered "expert opinion," rather than "evidence-based."

Appraising contemporary strategies to combat multidrug resistant gram-negative bacterial infections--proceedings and data from the Gram-Negative Resistance Summit

The emerging problem of antibiotic resistance, especially among Gram-negative bacteria (GNB), has become a serious threat to global public health. Very few new antibacterial classes with activity against antibiotic-resistant GNB have been brought to market. Renewed and growing attention to the development of novel compounds targeting antibiotic-resistant GNB, as well as a better understanding of strategies aimed at preventing the spread of resistant bacterial strains and preserving the efficacy of existing antibiotic agents, has occurred. The Gram-Negative Resistance Summit convened national opinion leaders for the purpose of analyzing current literature, epidemiologic trends, clinical trial data, therapeutic options, and treatment guidelines related to the management of antibiotic-resistant GNB infections. After an in-depth analysis, the Summit investigators were surveyed with regard to 4 clinical practice statements. The results then were compared with the same survey completed by 138 infectious disease and critical care physicians and are the basis of this article.

The efficacy of infection control interventions in reducing the incidence of extended-spectrum β-lactamase-producing Enterobacteriaceae in the nonoutbreak setting: A systematic review

We conducted a systematic review to examine the efficacy of infection control interventions for the control of ESBL-producing Enterobacteriaceae in hospitals in the non-outbreak setting. Although 4 uncontrolled, retrospective studies were included in the review, no well designed prospective studies capable of informing infection control practice were identified, underscoring the urgent need for research in this area.

Long-term carriage of extended-spectrum beta-lactamase-producing Escherichia coli

In 2009 we described an outbreak caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in southern Sweden that occurred during 2005-2006. An important finding from the investigation was the long carriage times of the ESBL-producing E. coli in several of the patients, which in some cases exceeded 30 months. Here we report findings from the continued follow-up of bacterial carriage. In September 2010, 5 of the 42 patients still carried the bacteria after a median of 58 months (range 41-59 months), 18 had had repeatedly negative cultures after shedding bacteria for a median of 7.5 months (range 0-39 months), 16 had died while still shedding the bacteria for a median of 9 months (range 0-38 months), and 3 had been lost to follow-up.

Wide dissemination of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella spp. in acute care and rehabilitation hospitals

A prospective surveillance system for extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E) and ESBL-producing Klebsiella spp. (ESBL-K) was implemented in 39 German hospitals with the aim of determining the incidence densities (IDs) of community-onset and hospital-onset cases and of identifying risk factors for high IDs of hospital-onset cases. During 2008, 2081 ESBL-E/K cases were documented. ESBL-E cases (n=1330, 63·9%) were more common than ESBL-K cases (n=751, 36·1%), but a higher proportion of ESBL-K cases (59%) than of ESBL-E cases (39·5%) were hospital-onset cases. The mean IDs were 0·54 (range 0–2·53) per 1000 patient-days for all ESBL-EK cases, 0·29 (range 0–1·81) per 1000 patient-days for community-onset ESBL-EK cases and 0·25 (range 0–1·82) per 1000 patient-days for hospital-onset ESBL-EK cases. Regression analysis showed a linear association between the IDs of community-onset and hospital-onset cases. The wide dissemination of ESBL-E and ESBL-K emphasizes the need for hospital-wide surveillance to guide control measures.

Impact of a change in antibiotic prophylaxis on total antibiotic use in a surgical intensive care unit

OBJECTIVE

The aim of this study was to evaluate the impact of reducing the length of antibiotic prophylaxis for cerebro spinal shunts on total antibiotic use and key resistant pathogens.

METHODS

In January 2004, the use of antibiotic prophylaxis was reduced to a single shot dose with cefuroxime in an intensive care unit (ICU). Prior to this intervention, prophylaxis with second-generation cephalosporins was administered during the entire period of external cerebro spinal fluid (CSF) drainage. The effect on the antibiotic use density (AD: DDD [defined daily doses] per 1,000 patient-days[pd]) was calculated prior to (January 2002-December 2003) and following implementation of the intervention(January 2004-December 2006) by segmented regression analysis of an interrupted time series. Resistance proportions(RP) and resistance densities (RD), defined as resistant pathogen/1,000 pd of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis or E. faecium, third-generation-resistant (3GC) Escherichia coli and Klebsiella pneumoniae, and imipenem-resistant Pseudomonus aeruginosa, were compared by the Fisher's exact test before and after the intervention.

RESULTS

Total antibiotic use by 147 DDD/1,000 pd decreased after the intervention when pre-operative prophylaxis was changed into single shot prophylaxis, from an estimated mean of 1,036 DDD/1,000 pd before the intervention to 887DDD/1,000 pd post-intervention. This decrease was primarily due to a significant reduction in the amount of cefuroxime used for prophylaxis. The reduction in total antibiotic consumption was sustainable, and it did not increase again during the next 36 months. The RR and RD of third-generation cephalosporin-resistant E. coli increased after January 2004, whereas the percentage of MRSA significantly decreased.

CONCLUSION

Change to single shot prophylaxis along with an ongoing antibiotic stewardship program resulted in a cut-back in total antibiotic use amounting to as much as 15%. It would therefore appear that targeting interventions aimed at reducing antibiotic prophylaxis in surgical ICUs may be very worthwhile.

Using active microbiologic surveillance and enhanced infection control measures to control an outbreak of health care-associated extended-spectrum beta-lactamase-producing Klebsiella pneumoniae infections--New Jersey, 2007

Between April and June 2007, an outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae infections occurred in an intensive care unit in New Jersey. The outbreak was contained through active microbiologic surveillance, contact precautions, cohorting, and frequent room cleaning. This outbreak demonstrates the importance of rapid response in identifying and isolating patients to prevent further transmission.

Prevalence and mechanisms of broad-spectrum beta-lactam resistance in Enterobacteriaceae: a children's hospital experience

The objective of this study was to investigate the trends and patterns of resistance in beta-lactamase-producing members of the family Enterobacteriaceae in a children's hospital over a 9-year period (1999 to 2007). Clinically significant isolates of the Enterobacteriaceae were screened for patterns of broad-spectrum resistance to beta-lactams. The strains likely to be resistant were subsequently confirmed by an inhibitor-based disc test. The plasmid-mediated resistance determinants in these isolates were identified by PCR and by in vitro transformation, which successfully reproduced the AmpC phenotype unrestricted by the species of the host organisms. Among 8,048 Enterobacteriaceae isolates belonging to the four chromosomal ampC-negative or -nonfunctional genera, 86 (1.07%) isolates (56 Escherichia coli isolates, 22 Klebsiella species isolates, 1 Proteus mirabilis isolate, and 7 Salmonella species isolates) exhibited broad-spectrum beta-lactam resistance patterns. These organisms collectively produced three classes of beta-lactamases, including class A extended-spectrum beta-lactamases (n = 47), class C or AmpC beta-lactamases (n = 36, including 4 isolates that produced both class A and class C enzymes), and class A or B carbapenem-hydrolyzing beta-lactamases (n = 3). The proportion increased from 0.46% during the first 3 years to 1.84% during the last 3 years (relative risk [RR], 4.04; 95% confidence interval [CI], 2.28 to 7.42; P < 0.001). The increase was mainly due to the emergence of a plasmid-mediated bla(CMY-2) beta-lactamase, the incidence of which increased from 0.11% during the first 3 years to 0.96% during the last 3 years (RR, 9.11; 95% CI, 2.76 to 30.1; P = 0.001). Class A-type resistance increased slightly during the study period, from 0.35% during the first 3 years to 0.85% during the last 3 years (RR, 2.42; 95% CI, 1.15 to 5.07; P = 0.02). A Proteus mirabilis strain was documented to possess a novel bla(DHA) determinant. Of special concern, three carbapenemase-producing isolates were identified between 2003 and 2006. The infections caused by resistant isolates of the Enterobacteriaceae mainly affected hospitalized patients with underlying conditions; however, 19 (22%) episodes were of community onset in otherwise well children. The rate of resistance to broad-spectrum beta-lactams among isolates of the Enterobacteriaceae is increasing in children in both hospital- and community-acquired settings, and the resistance is driven largely by plasmid-mediated AmpC beta-lactamases. These data have important implications for empirical antimicrobial strategies targeting serious pediatric infections. Further study of this problem is warranted.

Bloodstream infections caused by extended-spectrum-beta-lactamase- producing Escherichia coli: risk factors for inadequate initial antimicrobial therapy

Extended-spectrum-beta-lactamase (ESBL)-producing strains of Escherichia coli are a significant cause of bloodstream infections (BSI) in hospitalized and nonhospitalized patients. We previously showed that delaying effective antimicrobial therapy in BSI caused by ESBL producers significantly increases mortality. The aim of this retrospective 7-year analysis was to identify risk factors for inadequate initial antimicrobial therapy (IIAT) (i.e., empirical treatment based on a drug to which the isolate had displayed in vitro resistance) for inpatients with BSI caused by ESBL-producing E. coli. Of the 129 patients considered, 56 (43.4%) received IIAT for 48 to 120 h (mean, 72 h). Independent risk factors for IIAT include an unknown BSI source (odds ratios [OR], 4.86; 95% confidence interval [CI], 1.98 to 11.91; P = 0.001), isolate coresistance to >or=3 antimicrobials (OR, 3.73; 95% CI, 1.58 to 8.83; P = 0.003), hospitalization during the 12 months preceding BSI onset (OR, 3.33; 95% CI, 1.42 to 7.79; P = 0.005), and antimicrobial therapy during the 3 months preceding BSI onset (OR, 2.65; 95% CI, 1.11 to 6.29; P = 0.02). IIAT was the strongest risk factor for 21-day mortality and significantly increased the length of hospitalization after BSI onset. Our results underscore the need for a systematic approach to the management of patients with serious infections by ESBL-producing E. coli. Such an approach should be based on sound, updated knowledge of local infectious-disease epidemiology, detailed analysis of the patient's history with emphasis on recent contact with the health care system, and aggressive attempts to identify the infectious focus that has given rise to the BSI.

Screening for extended-spectrum beta-lactamase-producing Enterobacteriaceae among high-risk patients and rates of subsequent bacteremia

BACKGROUND

Bloodstream infections due to extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae have been associated with increased hospital costs, length of stay, and patient mortality. However, the role of routine inpatient surveillance for ESBL colonization in predicting related infection is unclear.

METHODS

From 2000 through 2005, we screened 17,872 patients hospitalized in designated high-risk units for rectal colonization with vancomycin-resistant enterococci and ESBL-producing Enterobacteriaceae using a selective culture medium. In patients with a bloodstream infection due to ESBL-producing Enterobacteriaceae (ESBL-BI) during the study period, surveillance results were evaluated for evidence of antecedent ESBL-producing Enterobacteriaceae colonization.

RESULTS

The rate of ESBL-producing Enterobacteriaceae colonization doubled during the 6-year study period, increasing from 1.33% of high-risk patients in 2000 to 3.21% in 2005. Among patients with ESBL-producing Enterobacteriaceae colonization, 49.6% also carried vancomycin-resistant enterococci. The number of ESBL-BIs increased >4-fold in 5 years, from 9 cases in 2001 to 40 cases in 2005. Of 413 patients colonized with ESBL-producing Enterobacteriaceae, 35 (8.5%) developed a subsequent ESBL-BI. Of concern, more than one-half of all ESBL-BIs occurred in patients who were not screened. These 56 patients received a diagnosis of ESBL-BI in the emergency department, when hospitalized in low-risk medical units, or at transfer from an acute or long-term health care facility.

CONCLUSIONS

Colonization with ESBL-producing Enterobacteriaceae is increasing at a rapid rate, and routine rectal surveillance for ESBL-producing Enterobacteriaceae may have clinical implications. However, in our experience, over one-half of patients with an ESBL-BI did not undergo screening through our current surveillance measures. As a result, targeted screening for ESBL-producing Enterobacteriaceae among additional patient populations may be integral to future ESBL-BI prevention and management efforts.