Remediation of Mucorales-contaminated Healthcare Linens at a Laundry Facility Following an Investigation of a Case Cluster of Hospital-acquired Mucormycosis.

BACKGROUND: In an investigation of hospital-acquired mucormycosis cases among transplant recipients, healthcare linens (HCLs) delivered to our center were found to be contaminated with Mucorales. We describe an investigation and remediation of Mucorales contamination at the laundry supplying our center. METHODS: We performed monthly RODAC cultures of HCLs upon hospital arrival, and conducted site inspections and surveillance cultures at the laundry facility. Remediation was designed and implemented by infection prevention and facility leadership teams. RESULTS: Prior to remediation, 20% of HCLs were culture-positive for Mucorales upon hospital arrival. Laundry facility layout and processes were consistent with industry standards. Significant step-ups in Mucorales and mold culture-positivity of HCLs were detected at the post-dryer step (0% to 12% [P = .04] and 5% to 29% [P = .01], respectively). Further increases to 17% and 40% culture-positivity, respectively, were noted during pre-transport holding. Site inspection revealed heavy Mucorales-positive lint accumulation in rooftop air intake and exhaust vents that cooled driers; intake and exhaust vents that were facing each other; rooftop and plant-wide lint accumulation, including in the pre-transport clean room; uncovered carts with freshly-laundered HCLs. Following environmental remediation, quality assurance measures and education directed toward these sources, Mucorales culture-positivity of newly-delivered HCLs was reduced to 0.3% (P = .0001); area of lint-contaminated rooftop decreased from 918 m2 to 0 m2 on satellite images. CONCLUSIONS: Targeted laundry facility interventions guided by site inspections and step-wise culturing significantly reduced Mucorales-contaminated HCLs delivered to our hospital. Collaboration between infection prevention and laundry facility teams was crucial to successful remediation.

A novel disinfection protocol using ATP testing for lead garments in the electrophysiology lab.

PURPOSE: Electrophysiology procedures pose infection risk and require surgical room sterility. Currently, there is no universally approved protocol for disinfecting lead garments in the electrophysiology laboratory. This study explores the feasibility of using ATP testing to assess the microbial burden of lead aprons and evaluates the impact of a sanitary intervention. METHODS: Adenosine triphosphate (ATP) testing is a well-established hospital standard to quantify biological matter on a surface and, by proxy, the microbial burden. It is measured in RLU (relative light units). Pre-intervention ATP testing was performed on 34 lead garments after use for electrophysiology procedures. The thyroid collar, mid-chest vest, and left axillary areas of the garments were swabbed using a Hygiena SystemSure II luminometer with ATP swabs (Hygiena, Camarillo, CA). These sites were then disinfected with disinfectant wipes (PDI Super Sani-cloth Germicidal Disposable Wipe) and ATP testing was repeated. RESULTS: The mean duration of garment wear was 213 min. The thyroid collars had the highest mean RLU before intervention, followed by the mid-chest vest and the left axillary areas. The intervention was found to significantly decrease ATP readings for all three sites (p = 0.0002, p = 0.0001, p = 0.0002 respectively). Linear regression modeling to assess the impact of intervention showed a significant correlation with pre-intervention ATP values for all three sites but no correlation with fluoroscopy time, fluoroscopy dose, or total time spent within the procedure. CONCLUSIONS: Lead garments harbor microbial contamination after use according to ATP testing. A sanitary intervention can decontaminate lead garments and potentially reduce rates of hospital infection.

Genetic diversity of clinical and environmental Mucorales isolates obtained from an investigation of mucormycosis cases among solid organ transplant recipients.

Mucormycoses are invasive infections by Rhizopus species and other Mucorales. Over 10 months, four solid organ transplant (SOT) recipients at our centre developed mucormycosis due to Rhizopus microsporus (n=2), R. arrhizus (n=1) or Lichtheimia corymbifera (n=1), at a median 31.5 days (range: 13-34) post-admission. We performed whole genome sequencing (WGS) on 72 Mucorales isolates (45 R. arrhizus, 19 R. delemar, six R. microsporus, two Lichtheimia species) from these patients, from five patients with community-acquired mucormycosis, and from hospital and regional environments. Isolates were compared by core protein phylogeny and global genomic features, including genome size, guanine-cytosine percentages, shared protein families and paralogue expansions. Patient isolates fell into six core phylogenetic lineages (clades). Phylogenetic and genomic similarities of R. microsporus isolates recovered 7 months apart from two SOT recipients in adjoining hospitals suggested a potential common source exposure. However, isolates from other patients and environmental sites had unique genomes. Many isolates that were indistinguishable by core phylogeny were distinct by one or more global genomic comparisons. Certain clades were recovered throughout the study period, whereas others were found at particular time points. In conclusion, mucormycosis cases could not be genetically linked to a definitive environmental source. Comprehensive genomic analyses eliminated false associations between Mucorales isolates that would have been assigned using core phylogenetic or less extensive genomic comparisons. The genomic diversity of Mucorales mandates that multiple isolates from individual patients and environmental sites undergo WGS during epidemiological investigations. However, exhaustive surveillance of fungal populations in a hospital and surrounding community is probably infeasible.

Bronchoscope-associated clusters of multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Klebsiella pneumoniae.

OBJECTIVE: Recovery of multidrug-resistant (MDR) Pseudomonas aeruginosa and Klebsiella pneumoniae from a cluster of patients in the medical intensive care unit (MICU) prompted an epidemiologic investigation for a common exposure. METHODS: Clinical and microbiologic data from MICU patients were retrospectively reviewed, MICU bronchoscopes underwent culturing and borescopy, and bronchoscope reprocessing procedures were reviewed. Bronchoscope and clinical MDR isolates epidemiologically linked to the cluster underwent molecular typing using pulsed-field gel electrophoresis (PFGE) followed by whole-genome sequencing. RESULTS: Of the 33 case patients, 23 (70%) were exposed to a common bronchoscope (B1). Both MDR P. aeruginosa and K. pneumonia were recovered from the bronchoscope's lumen, and borescopy revealed a luminal defect. Molecular testing demonstrated genetic relatedness among case patient and B1 isolates, providing strong evidence for horizontal bacterial transmission. MDR organism (MDRO) recovery in 19 patients was ultimately linked to B1 exposure, and 10 of 19 patients were classified as belonging to an MDRO pseudo-outbreak. CONCLUSIONS: Surveillance of bronchoscope-derived clinical culture data was important for early detection of this outbreak, and whole-genome sequencing was important for the confirmation of findings. Visualization of bronchoscope lumens to confirm integrity should be a critical component of device reprocessing.

Risk Factors for Surgical Site Infections Following Neurosurgical Spinal Fusion Operations: A Case Control Study.

OBJECTIVE To determine risk factors for the development of surgical site infections (SSIs) in neurosurgery patients undergoing spinal fusion. DESIGN Retrospective case-control study. SETTING Large, academic, quaternary care center. PATIENTS The study population included all neurosurgery patients who underwent spinal fusion between August 1, 2009, and August 31, 2013. Cases were defined as patients in the study cohort who developed an SSI. Controls were patients in the study cohort who did not develop an SSI. METHODS To achieve 80% power with an ability to detect an odds ratio (OR) of 2, we performed an unmatched case-control study with equal numbers of cases and controls. RESULTS During the study period, 5,473 spinal fusion procedures were performed by neurosurgeons in our hospital. With 161 SSIs recorded during the study period, the incidence of SSIs associated with these procedures was 2.94%. While anterior surgical approach was found to be a protective factor (OR, 0.20; 95% confidence interval [CI], 0.08-0.52), duration of procedure (OR, 1.58; 95% CI, 1.29-1.93), American Society of Anesthesiologists score of 3 or 4 (OR, 1.79; 95% CI, 1.00-3.18), and hospitalization within the prior 30 days (OR, 5.8; 95% CI, 1.37-24.57) were found in multivariate analysis to be independent predictors of SSI following spinal fusion. Prior methicillin-resistant Staphylococcus aureus (MRSA) nares colonization was highly associated with odds 20 times higher of SSI following spinal fusion (OR, 20.30; 95% CI, 4.64-8.78). CONCLUSIONS In additional to nonmodifiable risk factors, prior colonization with MRSA is a modifiable risk factor very strongly associated with development of SSI following spinal fusion. Infect Control Hosp Epidemiol 2017;38:348-352.

Draft Genome Sequences of Four Hospital-Associated Pseudomonas putida Isolates.

We present here the draft genome sequences of four Pseudomonas putida isolates belonging to a single clone suspected for nosocomial transmission between patients and a bronchoscope in a tertiary hospital. The four genome sequences belong to a single lineage but contain differences in their mobile genetic elements.

Genomic Epidemiology of an Endoscope-Associated Outbreak of Klebsiella pneumoniae Carbapenemase (KPC)-Producing K. pneumoniae.

Increased incidence of infections due to Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (KPC-Kp) was noted among patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) at a single hospital. An epidemiologic investigation identified KPC-Kp and non-KPC-producing, extended-spectrum ß-lactamase (ESBL)-producing Kp in cultures from 2 endoscopes. Genotyping was performed on patient and endoscope isolates to characterize the microbial genomics of the outbreak. Genetic similarity of 51 Kp isolates from 37 patients and 3 endoscopes was assessed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Five patient and 2 endoscope isolates underwent whole genome sequencing (WGS). Two KPC-encoding plasmids were characterized by single molecule, real-time sequencing. Plasmid diversity was assessed by endonuclease digestion. Genomic and epidemiologic data were used in conjunction to investigate the outbreak source. Two clusters of Kp patient isolates were genetically related to endoscope isolates by PFGE. A subset of patient isolates were collected post-ERCP, suggesting ERCP endoscopes as a possible source. A phylogeny of 7 Kp genomes from patient and endoscope isolates supported ERCP as a potential source of transmission. Differences in gene content defined 5 ST258 subclades and identified 2 of the subclades as outbreak-associated. A novel KPC-encoding plasmid, pKp28 helped define and track one endoscope-associated ST258 subclade. WGS demonstrated high genetic relatedness of patient and ERCP endoscope isolates suggesting ERCP-associated transmission of ST258 KPC-Kp. Gene and plasmid content discriminated the outbreak from endemic ST258 populations and assisted with the molecular epidemiologic investigation of an extended KPC-Kp outbreak.

Use of multilocus variable number of tandem repeats analysis genotyping to determine the role of asymptomatic carriers in Clostridium difficile transmission.

BACKGROUND: Previous studies have suggested that asymptomatic carriers of toxigenic Clostridium difficile are a source of hospital-associated (HA) infections. Multilocus variable number of tandem repeats analysis (MLVA) is a highly discriminatory molecular subtyping tool that helps to determine possible transmission sources. METHODS: Clostridium difficile isolates were recovered from perirectal swabs collected for vancomycin-resistant Enterococcus (VRE) surveillance as well as from clinical C. difficile toxin-positive stool samples from July to November 2009 at the University of Pittsburgh Medical Center Presbyterian (UPMC). MLVA was performed to determine the genetic relationships between isolates from asymptomatic carriers and patients with HA C. difficile infection (HA-CDI). Asymptomatic carriage and HA-CDI isolates were considered to be associated if the carriage isolate was collected before the HA-CDI isolate and if the MLVA genotypes had a summed tandem-repeat difference of ≤ 2. RESULTS: Of 3006 patients screened, 314 (10.4%) were positive for toxigenic C. difficile, of whom 226 (7.5%) were detected only by VRE surveillance cultures. Of 56 incident cases of CDI classified as HA at UPMC during the study with available isolates, 17 (30%) cases were associated with CDI patients, whereas 16 (29%) cases were associated with carriers. Transmission events from prior bed occupants with CDI (n = 2) or carriers (n = 2) were identified in 4 of 56 cases. CONCLUSIONS: In our hospital with an established infection control program designed to contain transmission from symptomatic CDI patients, asymptomatic carriers appear to have played an important role in transmission. Identification and isolation of carriers may be necessary to further reduce transmission of C. difficile in such settings.

Invasive polyarticular septic arthritis caused by nontypeable haemophilus influenzae in a young adult: a case report and literature review.

Nontypeable Haemophilus influenzae is a rare cause of septic arthritis in adults and has been reported to be associated with underlying medical conditions. We present a case of nontypeable H. influenzae-infected severe invasive polyarticular septic arthritis in a young adult without any underlying predisposing medical conditions. Diagnosis was made from both positive blood culture and joint aspiration culture. The patient was successfully treated with employment of aggressive surgical debridement of multiple affected septic joints as well as prolonged antibiotic treatment. Further laboratory testing did not reveal significant underlying medical conditions including negative HIV, normal levels of complement and IgG subclasses, and normal-appearing spleen on computed tomography. This case illustrates that nontypeable H. influenzae can cause serious invasive septic arthritis infection in both patients with and without predisposing underlying medical conditions and that prompt diagnosis with aggressive treatment of combined surgical and medical treatment can result in optimal recovery.

Perirectal swab surveillance for Clostridium difficile by use of selective broth preamplification and real-time PCR detection of tcdB.

Active surveillance testing to identify and isolate asymptomatic carriers of toxigenic Clostridium difficile has been limited by the lack of a test that is sensitive, specific, and timely enough to serve as an infection control tool. We tested DNA preamplified from perirectal surveillance specimens in a liquid medium selective for C. difficile by using a modified commercial real-time PCR assay. All fermenting specimens were subcultured, and isolates were tested for toxigenicity. Culture-positive toxigenic isolates served as the gold standard for comparison with the broth preamplification/PCR assay. The limit of detection for the assay was 1 CFU. Relative to toxigenic anaerobic culture, the sensitivity, specificity, and positive and negative predictive values of this assay were 70/70 (100.0%), 422/426 (99.1%), 70/74 (94.6%), and 422/422 (100.0%), respectively. These data demonstrate that selective broth preamplification and real-time PCR of perirectal swab specimens constitute a practical approach to the detection of asymptomatic C. difficile carriage.

Colistin-resistant, Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae belonging to the international epidemic clone ST258.

Five cases of infection due to colistin-resistant, Klebsiella pneumoniae carbapenemase-producing K. pneumoniae belonging to the international epidemic clone ST258 occurred over a 4-month period. These cases likely represented both emergence of resistance and transmission of resistant organism. The colistin-resistant isolates were able to persist in the absence of selective pressure in vitro.

Screening for Acinetobacter baumannii colonization by use of sponges.

There is currently no consensus method for the active screening of Acinetobacter baumannii. The use of swabs to culture nostrils, pharynx, and skin surface of various anatomical sites is known to yield less-than-optimal sensitivity. In the present study, we sought to determine whether the use of sterile sponges to sample large areas of the skin would improve the sensitivity of the detection of A. baumannii colonization. Forty-six patients known to be colonized with A. baumannii, defined by a positive clinical culture for this organism as defined by resistance to more than two classes of antimicrobials, participated in the study. The screening sites included the forehead, nostrils, buccal mucosa, axilla, antecubital fossa, groin, and toe webs with separate rayon swabs and the forehead, upper arm, and thigh with separate sponges. Modified Leeds Acinetobacter medium (mLAM) agar plates that contained vancomycin and either aztreonam or ceftazidime were used as the selective medium. An enrichment culture grown overnight substantially increased the sensitivity for most sites. The sensitivity ranged between 69.6 and 82.6% for individual sponge sites and 21.7 to 52.2% for individual swab sites when mLAM plates with ceftazidime were inoculated after a 24-h enrichment period. The sponge and swab sites with the best sensitivity were the leg and the buccal mucosa, respectively (82.6% and 52.2%; P = 0.003). The combined sensitivity for the upper arm and leg with a sponge was 89.1%. The novel screening method using sterile sponges was easy to perform and achieved excellent sensitivity for the detection of A. baumannii colonization.

Patient-associated risk factors for acquisition of methicillin-resistant Staphylococcus aureus in a tertiary care hospital.

BACKGROUND: Determining risk factors for acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals is important for defining infection-control measures that may lead to fewer hospital-acquired infections. OBJECTIVE: To determine patient-associated risk factors for acquisition of MRSA in a tertiary care hospital with the goal of identifying modifiable risk factors. METHODS: A retrospective matched case-control study was performed. Case patients who acquired MRSA during hospitalization and 2 matched control patients were selected among inpatients admitted to target units during the period from 2001 through 2008. The odds of exposure to potential risk factors were compared between case patients and control patients, using matched univariate conditional logistic regression. A single multivariate conditional logistic regression model identifying independent patient-specific risk factors was generated. RESULTS: A total of 451 case patients and 866 control patients were analyzed. Factors positively associated with MRSA acquisition were as follows: target unit stay before index culture; primary diagnosis of respiratory disease, digestive tract disease, injury or trauma, or other diagnosis compared with cardiocirculatory disease; peripheral vascular disease; mechanical ventilation with pneumonia; ventricular shunting or ventriculostomy; and ciprofloxacin use. Factors associated with decreased risk were receipt of a solid-organ transplant and use of penicillins, cephalosporins, rifamycins, daptomycin or linezolid, and proton pump inhibitors. CONCLUSION: Among the factors associated with increased risk, few are modifiable. Patients with at-risk conditions could be targeted for intensive surveillance to detect acquisition sooner. The association of MRSA acquisition with target unit exposure argues for rigorous application of hand hygiene, appropriate barriers, environmental control, and strict aseptic technique for all procedures performed on such patients. Our findings support focusing efforts to prevent MRSA transmission and restriction of ciprofloxacin use.

Molecular epidemiology of CTX-M-producing Escherichia coli isolates at a tertiary medical center in western Pennsylvania.

A combination of phenotypic and genotypic methods was used to investigate 70 unique Escherichia coli clinical isolates identified as producing extended-spectrum beta-lactamases (ESBLs) at a medical center in Pittsburgh, PA, between 2007 and 2008. Fifty-seven isolates (81%) produced CTX-M-type ESBLs, among which CTX-M-15 was predominant (n = 46). Isolates producing CTX-M-2, -9, -14, and -65 were also identified. One CTX-M-producing isolate coproduced CMY-2 cephalosporinase. Ten isolates (14%) produced SHV-type ESBLs, either SHV-5 or SHV-7. Two isolates produced only CMY-2 or -32. Pulsed-field gel electrophoresis revealed the presence of two major clusters of CTX-M-15-producing E. coli isolates, one in phylotype B2 (n = 15) and the other in phylotype A (n = 19). Of four phylotype B2 isolates that were able to transfer the bla(CTX-M-15)-carrying plasmids, three showed fingerprints related (>60%) to those of plasmids from phylotype A isolates. In phylotype B2, all CTX-M-15-producing isolates, as well as three isolates producing CTX-M-14, two producing SHV-5, and one producing SHV-7, belonged to the international epidemic clone defined by serotype O25:H4 and sequence type 131. The plasmids from eight of nine CTX-M-15-producing E. coli isolates of phylotype A that were examined were highly related to each other and were also found in two isolates belonging to phylotype D, suggesting horizontal transfer of this bla(CTX-M-15)-carrying plasmid between phylotypes. Our findings underscore the need to further investigate the epidemiology and virulence of CTX-M-producing E. coli in the United States.

High frequency of rifampin resistance identified in an epidemic Clostridium difficile clone from a large teaching hospital.

BACKGROUND: Rifampin is used as adjunctive therapy for Clostridium difficile-associated disease, and the drug's derivative, rifaximin, has emerged as an attractive antimicrobial for treatment of C. difficile-associated disease. Rifampin resistance in C. difficile strains has been reported to be uncommon. METHODS: We examined the prevalence of rifampin resistance among 470 C. difficile isolates (51.1% during 2001-2002 and 48.9% during 2005) from a large teaching hospital. Rifampin sensitivity was performed using E-test. The epidemic BI/NAP1 C. difficile clone was identified by tcdC genotyping and multilocus variable number of tandem repeats analysis. A 200-base pair fragment of the rpoB gene was sequenced for 102 isolates. Data on rifamycin exposures were obtained for all patients. RESULTS: Rifampin resistance was observed in 173 (36.8%) of 470 recovered isolates and 167 (81.5%) of 205 of epidemic clone isolates (P < .001). Six rpoB genotypes were associated with rifampin resistance. Of 8 patients exposed to rifamycins, 7 had rifampin-resistant C. difficile, compared with 166 of 462 unexposed patients (relative risk, 2.4; 95% confidence interval, 1.8-3.3). CONCLUSIONS: Rifampin resistance is common among epidemic clone C. difficile isolates at our institution. Exposure to rifamycins before the development of C. difficile-associated disease was a risk factor for rifampin-resistant C. difficile infection. The use of rifaximin may be limited for treatment of C. difficile-associated disease at our institution.

Genetic basis of multidrug resistance in Acinetobacter baumannii clinical isolates at a tertiary medical center in Pennsylvania.

A total of 49 unique clinical isolates of multidrug-resistant (MDR) Acinetobacter baumannii identified at a tertiary medical center in Pittsburgh, Pennsylvania, between August 2006 and September 2007 were studied for the genetic basis of their MDR phenotype. Approximately half of all A. baumannii clinical isolates identified during this period qualified as MDR, defined by nonsusceptibility to three or more of the antimicrobials routinely tested in the clinical microbiology laboratory. Among the MDR isolates, 18.4% were resistant to imipenem. The frequencies of resistance to amikacin and ciprofloxacin were high at 36.7% and 95.9%, respectively. None of the isolates was resistant to colistin or tigecycline. The presence of the carbapenemase gene bla(OXA-23) and the 16S rRNA methylase gene armA predicted high-level resistance to imipenem and amikacin, respectively. bla(OXA-23) was preceded by insertion sequence ISAba1, which likely provided a potent promoter activity for the expression of the carbapenemase gene. The structure of the transposon defined by ISAba1 differed from those reported in Europe, suggesting that ISAba1-mediated acquisition of bla(OXA-23) may occur as an independent event. Typical substitutions in the quinolone resistance-determining regions of the gyrA and parC genes were observed in the ciprofloxacin-resistant isolates. Plasmid-mediated quinolone resistance genes, including the qnr genes, were not identified. Fifty-nine percent of the MDR isolates belonged to a single clonal group over the course of the study period, as demonstrated by pulsed-field gel electrophoresis.