Control of an outbreak of carbapenem-resistant Pseudomonas aeruginosa in a haemato-oncology unit

In search of the best method to detect carriage of carbapenem-resistant Pseudomonas aeruginosa in humans: a systematic review

BACKGROUND

Detection of carbapenem-resistant Pseudomonas aeruginosa (CR-PA) in humans is important to prevent transmission. However, the most optimal culture method to detect CR-PA is unknown. This systematic review aims to determine which culture method is most sensitive and which culture methods are used to detect CR-PA in humans. Second, to establish the most feasible culture method taking into account the turnaround time (TAT), and third, to provide an overview of the sampling sites used to detect carriage.

METHODS

We systematically searched the electronic databases Embase, Medline Ovid, Cochrane, Scopus, CINAHL, and Web of Science until January 27, 2023. All diagnostic accuracy studies comparing two or more culture methods to detect CR-PA and recent outbreak or surveillance reports on CR-PA carriage or infection in humans, which describe culture methods and their results, were eligible for inclusion. We used QUADAS-2 guideline for diagnostic accuracy studies and the STROBE or ORION guideline for outbreak-surveillance studies to assess the risk of bias.

RESULTS

Six diagnostic accuracy studies were included. An enrichment broth was found to increase the detection of CR-PA. Using an enrichment broth extended the TAT by 18-24 h, yet selective media could reduce the TAT by 24 h compared to routine media. In total, 124 outbreak-surveillance studies were included, of which 17 studies with surveillance samples and 116 studies with clinical samples. In outbreak-surveillance studies with surveillance samples, perianal, rectal swabs or stools were the most common sampling site/specimen (13/17, 76%). A large variety was observed in whether and which kind of enrichment broth and selective media were used.

CONCLUSIONS

We found a benefit of using an enrichment step prior to inoculation of the material onto selective media for the detection of CR-PA. More research is needed to determine the most sensitive sampling site and culture method.

TRAIL REGISTRATION

This study was registered in the PROSPERO International prospective register of systematic reviews (registration number: CRD42020207390, http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42020207390 ).

Directed carbapenemase testing is no longer just for Enterobacterales: cost, labor, and workflow assessment of expanding carbapenemase testing to carbapenem-resistant P. aeruginosa

Molecular carbapenem-resistance testing, such as for the presence of carbapenemases genes, is commonly implemented for the detection of carbapenemase-producing Enterobacterales. Carbapenemase-producing P. aeruginosa is also associated with significant morbidity and mortality, although; prevalence may be underappreciated in the United States due to a lack of carbapenemase testing. The present study sought to compare hands-on time, cost and workflow implementation of carbapenemase gene testing in Enterobacterales and P. aeruginosa isolates versus sending out isolates to a public health laboratory (PHL) for testing to assess if in-house can provide actionable results. The time to carbapenemase gene results were compared. Differences in cost for infection prevention measures were extrapolated from the time of positive carbapenemase gene detection in-house versus PHL. The median time to perform carbapenemase gene testing was 7.5 min (range 5-14) versus 10 min (range 8-22) for preparation to send isolates to the PHL. In-house testing produced same day results compared with a median of 6 days (range 3-14) to receive results from PHL. Cost of in-house testing and send outs were similar ($46.92 versus $40.53, respectively). If contact precautions for patients are implemented until carbapenemase genes are ruled out, in-house testing can save an estimated $76,836.60 annually. Extension of in-house carbapenemase testing to include P. aeruginosa provides actionable results 3-14 days earlier than PHL Standard Pathway testing, facilitating guided therapeutic decisions and infection prevention measures. Supplemental phenotypic algorithms can be implemented to curb the cost of P. aeruginosa carbapenemases testing by identifying isolates most likely to harbour carbapenemases.

Breaking away from an endemic state of multidrug-resistant Pseudomonas aeruginosa by daily sink disinfection

The detection rate of multidrug-resistant Pseudomonas aeruginosa in patients admitted to 2 wards and the intensive care unit decreased from 20.3% (129 of 636 isolates) to 4.2% (37 of 889 isolates) after the start of disinfection of hand washing sinks using alkyl diaminoethylglycine hydrochloride.

Dual-action gallium-flavonoid compounds for combating Pseudomonas aeruginosa infection

The opportunistic pathogen Pseudomonas aeruginosa (P. aeruginosa) causes infections that are difficult to treat, which is due to the bacterial natural resistance to antibiotics. The bacterium is also able to form a biofilm that protects the bacterium from clearance by the human immune system and leads to chronic infection. Herein, we synthesized and characterized a novel gallium compound that interferes with both the iron metabolism and quorum sensing system of P. aeruginosa to achieve a significant bactericidal activity. The compound could substantially reduce the secretion of bacterial virulence factors as well as eliminate biofilm formation. Integrative omics analysis indicates that this compound can significantly disturb the gene transcription and metabolism of P. aeruginosa. The effectiveness of the gallium compound was further validated in mammalian cell and murine skin infection models. Our study offers a new strategy to design new gallium-based antimicrobials to combat P. aeruginosa infection.

Effects of screening strategies to detect carbapenem-resistant gram-negative bacteria: A systematic review

OBJECTIVE

This systematic review aims to summarize the evidence on the effects of screening strategies to detect carbapenem-resistant gram-negative bacteria (Enterobacteriaceae, Acinetobacter baumannii, and Pseudomonas aeruginosa).

METHODS

Eligible studies were randomized trials, non-randomized controlled trials, controlled before-after studies, and interrupted time series. We conducted searches in CENTRAL, PUBMED, Embase, Epistemonikos, and in multiple databases available in the Virtual Health Library (LILACS, Scielo, WHO IBECS, and PAHO IBECS). All the searches covered the period until 4 June 2021. No date or language restrictions were applied. Two reviewers independently evaluated potentially eligible studies according to predefined selection criteria, and extracted data on study characteristics, methods, outcomes, and risk of bias, using a predesigned standardized form. When possible, we intended to conduct meta-analyses using a random-effect model. We assessed the certainty of the evidence (CoE) and summarized the results using the GRADE approach.

RESULTS

Our search strategy yielded 57,451 references. No randomized trials were identified. Sixteen studies (one controlled before-after study and 15 interrupted time series) met our inclusion criteria and were included in the review. Most studies were conducted in tertiary care general hospitals from the United States, Europe, and Asia. Eleven studies included adult patients hospitalized in general wards and intensive care units, one was carried out in a neonatal intensive care unit, two in hematology or oncology units, and one in a solid organ transplantation department. Eleven studies were conducted in the setting of an outbreak. Regarding the detection strategy used, all studies included screening strategies for high-risk patients at the moment of admission and 7 studies reported a contact surveillance strategy. Most studies were conducted in settings where infection prevention and control measures were concomitantly installed or reinforced. Data were not suitable for meta-analysis, so the results were presented as a narrative synthesis. Most studies showed a decline in the prevalence of both infection and colonization rates after the implementation of a policy of active surveillance, but the CoE is low. Screening strategies may result in little to no difference in the risk of all-cause mortality and the length of hospital stay.

CONCLUSIONS

Existing evidence may favor the use of surveillance culture to carbapenem-resistant gram-negative bacteria, but its quality is poor, so solid conclusions cannot be drawn. Well-conducted randomized trials or high-quality quasi-experimental studies are needed to improve the certainty of the existing evidence. These studies should assess the effect of the addition of screening strategies as a single intervention and measure clinically important outcomes such as infection, length of hospital stay, and mortality.

An equation to estimate 24-hour total urine protein excretion rate in patients who underwent urine protein testing

Background

The urine protein-creatinine ratio (UPCR) in a spot first-morning urine sample is used to estimate 24-h urine proteinuria (24hUP) in patients who underwent urine protein testing. UPCR cannot be directly compared with 24-h proteinuria. Thus, an equation to estimate 24-h total protein excretion rate, using age, gender, and the UPCR may improve its bias and accuracy in patients who underwent urine protein testing.

Methods

We simultaneously measured 24-h urine protein and the same day’s first-morning spot urine from patients with kidney disease. Generalized linear and no-linear models, using age, gender, and UPCR, were constructed to estimate for 24-h urine protein and the best model (NJ equation) was selected to estimated 24 hUP (e24hUP).

Results

A total of 5435 paired samples (including a training cohort of 3803 patients and a validation cohort of 1632 patients) were simultaneously measured for UPCR and 24-h urine protein. In the training cohort, the unadjusted UPCR obviously underestimated 24-h urine protein when UPCR ≤1.2 g/g (median bias − 0.17 g/24 h) and overestimated 24-h urine protein when UPCR > 1.2 g/g (median bias 0.53 g/24 h). In the validation cohort, the NJ equation performed better than the unadjusted UPCR, with lower root mean square error (0.81 vs. 1.02, P < 0.001), less bias (median difference between measured and estimated urine protein, − 0.008 vs. 0.12), improved precision (interquartile range of the differences, 0.34 vs. 0.50), and greater accuracy (percentage of estimated urine protein within 30% of measured urine protein, 53.4% vs. 32.2%). Bland-Altman plot indicated that the agreement of spot and daily estimates was less pronounced with 24 hUP > 2 g than lower values.

Conclusions

The NJ e24hUP equation is more accurate than unadjusted UPCR to estimate 24 hUP in patients with kidney disease and could be used for laboratory application.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02673-2.

A View on 20 Years of Antimicrobial Resistance in Japan by Two National Surveillance Systems: The National Epidemiological Surveillance of Infectious Diseases and Japan Nosocomial Infections Surveillance

The Ministry of Health, Labour and Welfare (MHLW) of Japan has conducted two national surveillance systems for approximately 20 years to monitor antimicrobial resistance (AMR) in bacteria: the National Epidemiological Surveillance of Infectious Diseases (NESID) and the Japan Nosocomial Infections Surveillance (JANIS). Data accumulated for 20 years by these two surveillance systems have helped depict the epidemiology of the representative AMR bacteria in Japan chronologically. The epidemiology of methicillin-resistant Staphylococcus aureus teaches us that once AMR bacteria have established their high endemicity, controlling such AMR bacteria requires time and is challenging. On the other hand, the epidemiology that multidrug-resistant Acinetobacter sp. exhibits when a strict containment policy for AMR bacteria was introduced in the early phase of its emergence and spread reveals that it is possible to control it. Detailed epidemiology provided by these two different national surveillance systems in Japan enabled us to set up the goal for controlling each AMR bacteria at the hospital level to the prefecture/national level. It is the public health authorities' responsibility to maintain a good surveillance system for AMR bacteria and share the data and findings with healthcare professionals and academicians.

Guidelines for Infection Control in the Urological Field, including Urinary Tract Management (revised second edition)

The Committee for the Development of Guidelines for Infection Control in the Urological Field, including Urinary Tract Management of the Japanese Urological Association, together with its systematic review team and external reviewers, have prepared a set of practice guidelines, an abridged version of which is published herein. These guidelines cover the following topics: (i) foundations of infection control, standard precautions, route-specific precautions, and occupational infection control (including vaccines); (ii) the relationship between urologists and infection control; (iii) infection control in urological wards and outpatient clinics; (iv) response to hepatitis B virus reactivation; (v) infection control in urological procedures and examinations; (vi) prevention of infections occurring in conjunction with medical procedures and examinations; (vii) responses to urinary tract tuberculosis and bacillus Calmette-Guérin; (viii) aseptic handling, cleaning, disinfection, and sterilization of urinary tract endoscopes (principles of endoscope manipulation, endoscope lumen cleaning, and disinfection); (ix) infection control in the operating room (principles of hand washing, preoperative rubbing methods, etc.); (x) prevention of needlestick and blood/bodily fluid exposure and response to accidental exposure; (xi) urinary catheter-associated urinary tract infection and purple urinary bag syndrome; and (xii) urinary catheter-associated urinary tract infections in conjunction with home care. In addressing these topics, the relevant medical literature was searched to the extent possible, and content was prepared for the purpose of providing useful information for clinical practice.

Anti-biofilm Agents against Pseudomonas aeruginosa: A Structure-Activity Relationship Study of C-Glycosidic LecB Inhibitors

Biofilm formation is a key mechanism of antimicrobial resistance. We have recently reported two classes of orally bioavailable C-glycosidic inhibitors of the Pseudomonas aeruginosa lectin LecB with antibiofilm activity. They proved efficient in target binding, were metabolically stable, nontoxic, selective, and potent in inhibiting formation of bacterial biofilm. Here, we designed and synthesized six new carboxamides and 24 new sulfonamides for a detailed structure-activity relationship for two clinically representative LecB variants. Sulfonamides generally showed higher inhibition compared to carboxamides, which was rationalized based on crystal structure analyses. Substitutions at the thiophenesulfonamide increased binding through extensive contacts with a lipophilic protein patch. These metabolically stable compounds showed a further increase in potency toward the target and in biofilm inhibition assays. In general, we established the structure-activity relationship for these promising antibiofilm agents and showed that modification of the sulfonamide residue bears future optimization potential.

Spot urine protein/creatinine ratio as a reliable estimate of 24-hour proteinuria in patients with immunoglobulin A nephropathy, but not membranous nephropathy

BACKGROUND

Proteinuria is known to be associated with both kidney function deterioration and cardiovascular diseases. While proteinuria estimation from 24-h urine samples has traditionally been considered as the standard method for assessment of the degree of urinary protein excretion, sample collection is associated with several technical problems such as inaccurate collection and the potential spread of drug-resistant pathogens. Therefore, the spot urine protein/creatinine ratio (PCR) assessment is currently recommended as an alternative. While the utility of PCR has been validated, studies on the association between spot urine PCR and 24-h proteinuria (24HP) in patients with chronic glomerular nephritis (CGN) and nephrotic syndrome (NS) are limited. This study aimed to evaluate whether an estimated result from a spot urine PCR could sufficiently approximate the daily urine protein excretion amount from a 24-h urine sample in patients with immunoglobulin A nephropathy (IgAN), minimal change disease (MCD), and membranous nephropathy- nephrotic syndrome (MN-NS).

METHODS

The study participants included 161 patients with IgAN, MCD, or MGN-NS at the Jikei University Kashiwa Hospital and Kanagawa Prefecture Shiomidai Hospital. The correlation between spot urine PCR and a 24-h urine protein was investigated using linear regression analysis with Spearman's correlation (r) coefficient and intraclass correlation coefficient (ICC).

RESULTS

While high correlation coefficients (r = 0.86, P < 0.001) and substantial agreement (ICC: 0.806, P < 0.001) were observed in patients with IgAN, similar correlations were not observed in patients with MCD or MN-NS. In the patients with MCD, r was 0.53 (P < 0.001), which signified a slight correlation, and in the patients with MN-NS, r was 0.289 (P = 0.17), which was not statistically significant.

CONCLUSIONS

This study revealed that spot urine PCR is a reliable estimate of 24HP value in patients with IgAN. In contrast, there is a considerable difference between the daily urine protein excretion amount based on a 24-h urine sample and that which is calculated from spot urine PCR in patients with NS.

Control of Carbapenem-resistant Enterobacteriaceae, Acinetobacter baumannii, and Pseudomonas aeruginosa in Healthcare Facilities: A Systematic Review and Reanalysis of Quasi-experimental Studies

Carbapenem-resistant Enterobacteriaceae (CRE), Acinetobacter baumannii (CRAB), and Pseudomonas aeruginosa (CRPsA) are a serious cause of healthcare-associated infections, although the evidence for their control remains uncertain. We conducted a systematic review and reanalysis to assess infection prevention and control (IPC) interventions on CRE-CRAB-CRPsA in inpatient healthcare facilities to inform World Health Organization guidelines. Six major databases and conference abstracts were searched. Before-and-after studies were reanalyzed as interrupted time series if possible. Effective practice and organization of care (EPOC) quality criteria were used. Seventy-six studies were identified, of which 17 (22%) were EPOC-compatible and interrupted time series analyses, assessing CRE (n = 11; 65%), CRAB (n = 5; 29%) and CRPsA (n = 3; 18%). IPC measures were often implemented using a multimodal approach (CRE: 10/11; CRAB: 4/5; CRPsA: 3/3). Among all CRE-CRAB-CRPsA EPOC studies, the most frequent intervention components included contact precautions (90%), active surveillance cultures (80%), monitoring, audit and feedback of measures (80%), patient isolation or cohorting (70%), hand hygiene (50%), and environmental cleaning (40%); nearly all studies with these interventions reported a significant reduction in slope and/or level. The quality of EPOC studies was very low to low.

Control of Multidrug-Resistant Pseudomonas aeruginosa in Allogeneic Hematopoietic Stem Cell Transplant Recipients by a Novel Bundle Including Remodeling of Sanitary and Water Supply Systems

Background

Infections by multidrug-resistant Pseudomonas aeruginosa (MDRPa) are an important cause of morbidity and mortality in patients after allogeneic hematopoietic stem cell transplantation (HSCT). Humid environments can serve as a reservoir and source of infection by this pathogen. To minimize the risk of infection from these reservoirs, we performed extensive remodeling of sanitation and water installations as the focus of our hygiene bundle.

Methods

During the reconstruction of our transplantation unit (April 2011-April 2014) we implemented several technical modifications to reduce environmental contamination by and subsequent spreading of MDRPa, including a newly designed shower drain, disinfecting siphons underneath the sinks, and rimless toilets. During a 3-year study period (2012-2014), we tracked the number of patients affected by MDRPa (colonized and/or infected) and the outcome of infected patients, and monitored the environmental occurrence of this pathogen. We further performed whole-genome sequencing of nosocomial MDRPa strains to evaluate genotypic relationships between isolates.

Results

Whereas 31 (9.2%; 18 colonized, 13 infected) patients were affected in 2012 and 2013, the number decreased to 3 in 2014 (17%; 3 colonized, 0 infected). Lethality by MDRPa similarly decreased from 3.6% to 0%. Environmental detection of MDRPa decreased in toilets from 18.9% in 2012-2013 to 6.1% in the following year and from 8.1% to 3.0%, respectively, in shower outlets. Whole-genome sequencing showed close relationships between environmental and patient-derived isolates.

Conclusions

Hospital construction measures aimed at controlling environmental contamination by and spread of MDRPa are effective at minimizing the risk of highly lethal MDRPa infections.

Glycomimetic, Orally Bioavailable LecB Inhibitors Block Biofilm Formation of Pseudomonas aeruginosa

The opportunistic Gram-negative bacterium Pseudomonas aeruginosa is a leading pathogen for infections of immuno-compromised patients and those suffering from cystic fibrosis. Its ability to switch from planktonic life to aggregates, forming the so-called biofilms, is a front-line mechanism of antimicrobial resistance. The bacterial carbohydrate-binding protein LecB is an integral component and necessary for biofilm formation. Here, we report a new class of drug-like low molecular weight inhibitors of the lectin LecB with nanomolar affinities and excellent receptor binding kinetics and thermodynamics. This class of glycomimetic inhibitors efficiently blocked biofilm formation of P. aeruginosa in vitro while the natural monovalent carbohydrate ligands failed. Furthermore, excellent selectivity and pharmacokinetic properties were achieved. Notably, two compounds showed good oral bioavailability, and high compound concentrations in plasma and urine were achieved in vivo.

Detection of metallo-β-lactamases-encoding genes among clinical isolates of Pseudomonas aeruginosa in a tertiary care hospital, Kathmandu, Nepal

Objectives

This study was carried out to determine the prevalence of metallo-β-lactamases (MBLs) producing Pseudomonas aeruginosa in imipenem-nonsusceptible isolates and to detect MBL-encoding genes among MBLs-positive isolates.

Results

Metallo-β-lactamases production was detected in 68.6% isolates of P. aeruginosa with reduced susceptibility to imipenem. The bla_VIM-2 gene was detected in 75% isolates and bla_IMP-1 was detected in 25% isolates. All MBLs-positive isolates were multidrug resistant with a high level of resistance to imipenem (MIC 16 to ≥ 32 µg/ml), meropenem (MIC 16 to ≥ 32 µg/ml), and ceftazidime (MIC 64 to ≥ 512 µg/ml). All MBL-positive isolates were susceptible (MIC ≤ 2 µg/ml) to colistin. We found high prevalence of MBL-producing P. aeruginosa. To our knowledge this is the first report of detection of bla_VIM-2 and bla_IMP-1 in P. aeruginosa from Nepal. This indicates the need for awareness to prevent the spreading of these resistant isolates in hospital setting.

High mortality of bloodstream infection outbreak caused by carbapenem-resistant P. aeruginosa producing SPM-1 in a bone marrow transplant unit

PURPOSE

Carbapenem resistance in P. aeruginosa is increasing worldwide. In Brazil, SPM-1 is the main P. aeruginosa carbapenemase identified. Little is known about the virulence factor in SPM-1 clones.Methodolgy. We describe a carbapenem-resistant P. aeruginosa bloodstream infection (CRPa-BSI) outbreak in a bone marrow transplant Unit (BMT). Twenty-nine CRPa-BSI cases were compared to 58 controls. Microbiological characteristics of isolates, such as sensitivity, carbapenemase gene PCR for P. aeruginosa, and PFGE are described, as well as the whole-genome sequence (WGS) of three strains.Results/Key findings. The cultures from environmental and healthcare workers were negative. Some isolates harboured KPC and SPM. The WGS showed that the 03 strains belonged to ST277, presented the same mutations in outer membrane protein, efflux pump, and virulence genes such as those involved in adhesion, biofilm, quorum-sensing and the type III secretion system, but differ regarding the carbapenemase profile. A predominant clone-producing SPM harbouring Tn 4371 was identified and showed cross-transmission; no common source was found. Overall mortality rate among cases was 79 %. The first multivariate analysis model showed that neutropenia (P=0.018), GVHD prophylaxis (P=0.016) and prior use of carbapenems (P=0.0089) were associated with CRPa-BSI. However, when MASCC>21 points and platelets were added in the final multivariate analysis, only prior use of carbapenems remained as an independent risk factor for CRPa-BSI (P=0.043).

CONCLUSIONS

The predominant clone belonging to ST277 showed high mortality. Carbapenem use was the only risk factor associated with CRPa-BSI. This finding is a wake-up call for the need to improve management in BMT units.

Bacterial Infections in Hematopoietic Stem Cell Transplant Recipients

Bacterial infections are major complications after Hematopoietic Stem Cell Transplant (HSCT). They consist mainly of bloodstream infections (BSI), followed by pneumonia and gastrointestinal infections, including typhlitis and Clostridium difficile infection. Microbiological data come mostly from BSI. Coagulase negative staphylococci and Enterobacteriaceae are the most frequent pathogens causing approximately 25% of BSI each, followed by enterococci, P. aeruginosa and viridans streptococci. Bacterial pneumonia is frequent after HSCT, and Gram-negatives are predominant. Clostridium difficile infection affects approximately 15% of HSCT recipients, being more frequent in case of allogeneic than autologous HSCT. The epidemiology and the prevalence of resistant strains vary significantly between transplant centres. In some regions, multi-drug resistant (MDR) Gram-negative rods are increasingly frequent. In others, vancomycin-resistant enterococci are predominant. In the era of increasing resistance to antibiotics, the efficacy of fluoroquinolone prophylaxis and standard treatment of febrile neutropenia have been questioned. Therefore, a thorough evaluation of local epidemiology is mandatory to decide the need for prophylaxis and the choice of the best regimen for empirical treatment of febrile neutropenia. For the latter, individualised approach has been proposed, consisting of either escalation or de-escalation strategy. De-escalation strategy is recommended since resistant bacteria should be covered upfront, mainly in patients with severe clinical presentation and previous infection or colonisation with a resistant pathogen. Non-pharmacological interventions, such as screening for resistant bacteria, applying isolation and contact precautions should be put in place to limit the spread of MDR bacteria. Antimicrobial stewardship program should be implemented in transplant centres.

Epidemiology and Characteristics of Metallo-β-Lactamase-Producing Pseudomonas aeruginosa

Metallo-β-lactamase-producing Pseudomonas aeruginosa (MPPA) is an important nosocomial pathogen that shows resistance to all β-lactam antibiotics except monobactams. There are various types of metallo-β-lactamases (MBLs) in carbapenem-resistant P. aeruginosa including Imipenemase (IMP), Verona integron-encoded metallo-β-lactamase (VIM), Sao Paulo metallo-β-lactamase (SPM), Germany imipenemase (GIM), New Delhi metallo-β-lactamase (NDM), Florence imipenemase (FIM). Each MBL gene is located on specific genetic elements including integrons, transposons, plasmids, or on the chromosome, in which they carry genes encoding determinants of resistance to carbapenems and other antibiotics, conferring multidrug resistance to P. aeruginosa. In addition, these genetic elements are transferable to other Gram-negative species, increasing the antimicrobial resistance rate and complicating the treatment of infected patients. Therefore, it is essential to understand the epidemiology, resistance mechanism, and molecular characteristics of MPPA for infection control and prevention of a possible global health crisis. Here, we highlight the characteristics of MPPA.

A systematic review and meta-analyses show that carbapenem use and medical devices are the leading risk factors for carbapenem-resistant Pseudomonas aeruginosa

A systematic review and meta-analyses were performed to identify the risk factors associated with carbapenem-resistant Pseudomonas aeruginosa and to identify sources and reservoirs for the pathogen. A systematic search of PubMed and Embase databases from 1 January 1987 until 27 January 2012 identified 1,662 articles, 53 of which were included in a systematic review and 38 in a random-effects meta-analysis study. The use of carbapenem, use of fluoroquinolones, use of vancomycin, use of other antibiotics, having medical devices, intensive care unit (ICU) admission, having underlying diseases, patient characteristics, and length of hospital stay were significant risk factors in multivariate analyses. The meta-analyses showed that carbapenem use (odds ratio [OR] = 7.09; 95% confidence interval [CI] = 5.43 to 9.25) and medical devices (OR = 5.11; 95% CI = 3.55 to 7.37) generated the highest pooled estimates. Cumulative meta-analyses showed that the pooled estimate of carbapenem use was stable and that the pooled estimate of the risk factor "having medical devices" increased with time. We conclude that our results highlight the importance of antibiotic stewardship and the thoughtful use of medical devices in helping prevent outbreaks of carbapenem-resistant P. aeruginosa.

Surveillance and correlation of antimicrobial usage and resistance of Pseudomonas aeruginosa: a hospital population-based study

This retrospective study evaluated trends and association between resistance of Pseudomonas aeruginosa isolated from patients with hospital-acquired infections (HAIs) and hospital antimicrobial usage from 2003 through 2011 in a tertiary care hospital in northeast China. HAI was defined as occurrence of infection after hospital admission, without evidence that infection was present or incubating (≦48 h) on admission. In vitro susceptibilities were determined by disk diffusion test and susceptibility profiles were determined using zone diameter interpretive criteria, as recommended by Clinical and Laboratory Standards Institute (CLSI). Data on usage of various antimicrobial agents, expressed as defined daily dose (DDD) per 1,000 patients-days developed by WHO Anatomical Therapeutical Chemical (ATC)/DDD index 2011, were collected from hospital pharmacy computer database. Most of 747 strains of P. aeruginosa were collected from respiratory samples (201 isolates, 26.9%), blood (179, 24.0%), secretions and pus (145, 19.4%) over the years. Time series analysis demonstrated a significant increase in resistance rates of P. aeruginosa to ticarcillin/clavulanic acid, piperacillin/tazobactam, cefoperazone/sulbactam, piperacillin, imipenem, meropenem, ceftazidime, cefepime, ciprofloxacin, and levofloxacin except aminoglycosides over time in the hospital (P<0.001). The rates of carbapenem-resistant P. aeruginosa (CRPA) isolated from patients with HAIs were 14.3%, 17.1%, 21.1%, 24.6%, 37.0%, 48.8%, 56.4%, 51.2%, and 54.1% over time. A significant increase in usage of anti-pseudomonal carbapenems (P<0.001) was seen. ARIMA models demonstrated that anti-pseudomonal carbapenems usage was strongly correlated with the prevalence of imipenem and meropenem-resistant P. aeruginosa (P<0.001). Increasing of quarterly CRPA was strongly correlated at one time lag with quarterly use of anti-pseudomonal carbapenems (P<0.001). Our data demonstrated positive correlation between anti-pseudomonal antimicrobial usage and P. aeruginosa resistance to several classes of antibiotics, but not all antimicrobial agents in the hospital.

Worldwide challenges of multidrug-resistant bacteria in patients with hematologic malignancies

SUMMARY The emergence of infections due to multidrug-resistant (MDR) bacteria poses a major public health threat to all patients, but patients with hematologic malignancies are especially at risk. A common thread across all classes of bacteria is that increased reliance on and usage of broad-spectrum antibacterial agents, combined with the intrinsic ability of bacteria to develop and transmit resistance-conferring mutations, has led to the widespread dissemination of MDR organisms. In this article, we summarize the most worrisome MDR bacteria, assess their clinical impact on patients with hematologic malignancies and outline measures that are required to mitigate this impact.

Susceptibility of Pseudomonas aeruginosa isolates collected from river water in Japan to antipseudomonal agents

Pseudomonas aeruginosa is responsible for a number of opportunistic and nosocomial infections. However, very little information is available on the ecology of P. aeruginosa in water environments and its association with antimicrobial resistance. In this study, the distribution of P. aeruginosa and the resistance of P. aeruginosa isolates to various antibiotics were investigated from two rivers, Kiyotake and Yae that flow through Miyazaki City, Japan. P. aeruginosa was distributed widely along the river basins with counts ranging from 2-46 cfu/100 mL. The susceptibility of P. aeruginosa isolates collected from the rivers to various antibiotics was examined by minimum inhibitory concentration. Multidrug-resistant P. aeruginosa strains were not observed or isolated from either river. However, one piperacillin-resistant P. aeruginosa was detected among a total of 516 isolates, and this isolate was also resistant to cefotaxime and showed intermediate resistance to cefitazidime. Less than 1% of all isolates (n=5) were resistant to imipenem, which is the most effective antibiotic against both Gram-negative and Gram-positive bacteria. However, all P. aeruginosa isolates were completely resistant to tetracyclines, which are the most commonly prescribed antibiotics. In advanced nations such as Japan where the majority of the population is urban and where medical services are widespread, antibiotic-resistant bacteria such as P. aeruginosa are likely to be widely distributed, even in apparently pristine rivers.