The Hospital Water Environment as a Reservoir for Carbapenem-Resistant Organisms Causing Hospital-Acquired Infections-A Systematic Review of the Literature.

Over the last 20 years there have been 32 reports of carbapenem-resistant organisms in the hospital water environment, with half of these occurring since 2010. The majority of these reports have described associated clinical outbreaks in the intensive care setting, affecting the critically ill and the immunocompromised. Drains, sinks, and faucets were most frequently colonized, and Pseudomonas aeruginosa the predominant organism. Imipenemase (IMP), Klebsiella pneumoniae carbapenemase (KPC), and Verona integron-encoded metallo-ß-lactamase (VIM) were the most common carbapenemases found. Molecular typing was performed in almost all studies, with pulse field gel electrophoresis being most commonly used. Seventy-two percent of studies reported controlling outbreaks, of which just more than one-third eliminated the organism from the water environment. A combination of interventions seems to be most successful, including reinforcement of general infection control measures, alongside chemical disinfection. The most appropriate disinfection method remains unclear, however, and it is likely that replacement of colonized water reservoirs may be required for long-term clearance.

Isolation and plasmid characterization of carbapenemase (IMP-4) producing Salmonella enterica Typhimurium from cats.

Carbapenem-resistant Enterobacteriaceae (CRE) are a pressing public health issue due to limited therapeutic options to treat such infections. CREs have been predominantly isolated from humans and environmental samples and they are rarely reported among companion animals. In this study we report on the isolation and plasmid characterization of carbapenemase (IMP-4) producing Salmonella enterica Typhimurium from a companion animal. Carbapenemase-producing S. enterica Typhimurium carrying blaIMP-4 was identified from a systemically unwell (index) cat and three additional cats at an animal shelter. All isolates were identical and belonged to ST19. Genome sequencing revealed the acquisition of a multidrug-resistant IncHI2 plasmid (pIMP4-SEM1) that encoded resistance to nine antimicrobial classes including carbapenems and carried the blaIMP-4-qacG-aacA4-catB3 cassette array. The plasmid also encoded resistance to arsenic (MIC-150 mM). Comparative analysis revealed that the plasmid pIMP4-SEM1 showed greatest similarity to two blaIMP-8 carrying IncHI2 plasmids from Enterobacter spp. isolated from humans in China. This is the first report of CRE carrying a blaIMP-4 gene causing a clinical infection in a companion animal, with presumed nosocomial spread. This study illustrates the broader community risk entailed in escalating CRE transmission within a zoonotic species such as Salmonella, and in a cycle that encompasses humans, animals and the environment.

Nocardia Septic Arthritis Complicating an Anterior Cruciate Ligament Repair.

Nocardia infection following anterior cruciate ligament (ACL) allograft reconstruction is a rare occurrence. We report a case of Nocardia infection of an allograft ACL reconstruction and septic arthritis of the knee joint due to an organism most similar to the novel Nocardia species Nocardia aobensis.

Anncaliia algerae microsporidial myositis.

The insect microsporidian Anncaliia algerae was first described in 2004 as a cause of fatal myositis in an immunosuppressed person from Pennsylvania, USA. Two cases were subsequently reported, and we detail 2 additional cases, including the only nonfatal case. We reviewed all 5 case histories with respect to clinical characteristics, diagnosis, and management and summarized organism life cycle and epidemiology. Before infection, all case-patients were using immunosuppressive medications for rheumatoid arthritis or solid-organ transplantation. Four of the 5 case-patients were from Australia. All diagnoses were confirmed by skeletal muscle biopsy; however, peripheral nerves and other tissues may be infected. The surviving patient received albendazole and had a reduction of immunosuppressive medications and measures to prevent complications. Although insects are the natural hosts for A. algerae, human contact with water contaminated by spores may be a mode of transmission. A. algerae has emerged as a cause of myositis, particularly in coastal Australia.

Dientamoeba fragilis: a family cluster of disease associated with marked peripheral eosinophilia.

Dientamoeba fragilis has emerged as an important and underrecognized cause of gastrointestinal illness. We report a familial cluster of D. fragilis associated with marked peripheral eosinophilia and gastrointestinal symptoms. Dientamoeba fragilis infection should be considered in the setting of unexplained eosinophilia. If confirmed, screening of household members should be considered.

Plasmids and bacterial strains mediating multidrug-resistant hospital-acquired infections are coresidents of the hospital environment.

Hospital-acquired infections (HAIs) are a global problem. The widespread use of antibiotics continues to exacerbate the problem giving rise to antibiotic-resistant bacteria both in and outside a clinical context. The general hospital environment is an obvious important focus for the selection and spread of multiresistant bacteria and a potential direct source of HAIs. Despite this, there are few detailed studies that have investigated the relationship between strains mediating HAIs and strains coresident in the hospital. Here we isolated bacteria from patients with HAIs exhibiting resistance to ß-lactam antibiotics over a 1-month period in 2011. Three of these isolates were examined in detail by molecular analysis and their multiresistance regions were compared to ß-lactam resistant bacteria isolated from the immediate hospital environment over the same period. All sampled patients were in a 14-bed burns unit and the environmental sample sites included shower drains, sinks, trolleys, and door handles. It was found that identical strains carrying the same resistance regions were present in both patients and the hospital environment suggesting HAIs can arise from bacteria resident in the immediate surrounds. The three patient infections were not derived from a single source, since strains could be distinguished by the genotype and spatial location. While it seems unlikely that eradication of multiresistant bacteria from the hospital can be achieved, more effective hospital cleaning and a better hospital design may be able to reduce transmission.

Reusable venesection tourniquets: a potential source of hospital transmission of multiresistant organisms.

OBJECTIVE: To determine the prevalence of multiresistant organism (MRO) colonisation of reusable venesection tourniquets. DESIGN AND SETTING: A prospective study in a tertiary hospital to collect and analyse reusable venesection tourniquets for the presence of MROs - methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and extended-spectrum ß-lactamase and metallo-ß-lactamase-producing Enterobacteriaceae - using a sensitive enrichment method. Tourniquets were collected and tested during a 10-week period between September and November 2010. MAIN OUTCOME MEASURE: Prevalence of MRO colonisation of tourniquets. RESULTS: The overall colonisation rate of 100 tourniquets randomly collected from general wards, ambulatory care areas and critical care areas was 78%. MROs were isolated from 25 tourniquets collected from a variety of hospital locations, including general wards, the intensive care unit, burns unit and anaesthetic bay. MRSA was isolated from 14 tourniquets and VRE from 19; both MRSA and VRE were isolated from nine tourniquets. There were no microorganisms isolated from 22 tourniquets. CONCLUSION: Reusable tourniquets can be colonised with MROs and may be a potential source of transmission of MROs to hospitalised patients.

Tn6060, a transposon from a genomic island in a Pseudomonas aeruginosa clinical isolate that includes two class 1 integrons.

A 25,441-bp transposon was recovered from a Pseudomonas aeruginosa clinical isolate. While the transposition module was >99% identical to sequence of Tn1403, the element had been subject to rearrangements, with two In70.2-like class 1 integrons inserted into it in an unusual "tail-to-tail" configuration. One cassette array was the same as that in In70.2; however, the second was different, generating a transposon that collectively includes six resistance cassettes.