Prevalence of healthcare-associated infection at a tertiary hospital in the Northern Cape Province, South Africa

Background: Healthcare-associated infections (HCAIs) are a well-known public health threat; however, published data on the endemic burden of HCAIs in sub-Saharan Africa are limited. This study aimed to determine the prevalence of primary bloodstream infection (PBSI), surgical site infection (SSI), lower respiratory tract infection (LRTI) and urinary tract infection (UTI) at Kimberley Hospital Complex (KHC), Northern Cape.Methods: A one-day pointprevalence survey was conducted between February 2016 and March 2016 on all patients admitted to 15 selected wards at KHC. The Standardised Centers for Disease Control and National Nosocomial Infection Surveillance Systems criteria were used.Results: A total of 326 patients were surveyed and the overall HCAI prevalence rate was 7.67%. This included 4.60% SSIs, 1.53% UTIs, 0.92% PBSIs and 0.92% LRTIs. Patients with HCAI stayed a mean of 20.8 days compared with 9.1 days for the remaining patients. Almost 75% (n = 240) of the surveyed patients had one or more recognised risk factors. The most isolated microorganism among the 11 microorganisms isolated was Klebsiella pneumoniae (36.4%). Half (54.5%) of the isolated organisms were resistant to penicillin. At the time of the survey, 42.0% of all the patients were on antimicrobials of which amoxicillin/clavulanic acid was most commonly prescribed (29.9%). Conclusion: The overall HCAI prevalence rate found in KHC is encouraging, but the prevalence of SSI is of concern. Further studies are needed to identify risk factors and target this as an area where preventative interventions can be implemented.

Ultrasound-guided adductor canal block: a cadaver study investigating the effect of a thigh tourniquet

BACKGROUND

Placement of local anaesthetic within the adductor canal using ultrasonography is an alternative to femoral nerve blocks for postoperative pain relief after knee joint replacement surgery. However, the effect of an inflated thigh tourniquet on the distribution of local anaesthetic within the adductor canal is unknown. The aim of this cadaveric study was to compare the distribution of radio-opaque dye within the adductor canal in the presence or absence of an inflated thigh tourniquet.

METHODS

Bilateral ultrasound-guided adductor canal blocks were performed on the thawed lower limbs of five fresh frozen human cadavers. The left and right lower cadaver limbs were randomised to receive or not receive a thigh tourniquet inflated to 300 mm Hg for 1 h. X-rays with iohexol radio-opaque dye were obtained in four views, and fiducial markers inserted as reference points. Virtual editing technology was used to recreate outlines representing the distribution of the radio-opaque dye and superimpose these on anatomical images.

RESULTS

Radio-opaque dye was distributed on the medial aspect of the thighs with entire and well circumscribed margins. The majority of the radio-opaque dye was confined within the adductor canal. Superior-inferior dye distribution was 315 mm [95% confidence intervals (CI) 289-342] and 264 mm (95% CI 239-289) in the presence and absence of an inflated thigh tourniquet, respectively (diff 95% CI -80.46 to -22.22, P=0.0081). Image analysis using the recreated radio-opaque outlines suggested that the most proximal point of the radio-opaque dye was 100 mm (95% CI 82-117) or 117 mm (95% CI 62-171) below the inguinal ligament in the presence and absence of an inflated thigh tourniquet, respectively (diff 95% CI -38 to 72, P=0.456).

CONCLUSIONS

Application and inflation of thigh tourniquets significantly increased the combined superior-inferior dye distribution within the adductor canal of cadaveric limbs. There was insufficient evidence to suggest significant proximal spread of 25 ml of local anaesthetic to involve the motor branches of the femoral nerve. In some patients, the local anaesthetic may reach the popliteal fossa in close approximation to the sciatic nerve.

Abstract P3-04-02: Molecular analysis of breast cancers from individuals with hereditary cancer syndromes secondary to mutations in BRCA1, BRCA2, ATM, CHEK2, and PALB2

Background: Despite a growing understanding of the somatic landscape of breast tumors from BRCA1 and BRCA2 mutation carriers, less is known about breast tumors from carriers of germline mutations in other homologous recombination and DNA repair pathway genes such as ATM, CHEK2, and PALB2.

Methods: We identified 44 clinically annotated breast cancer cases that included carriers of germline mutations in BRCA1 (n=9), BRCA2 (n=9), ATM (n=5), CHEK2 (n=7), and PALB2 (n=6) from the Hereditary Cancer Risk Program at BUMC. Sporadic breast cancers cases (n=8) were also collected. Genomic DNA and RNA were extracted from macro-dissected FFPE tumor sections, adjacent normal FFPE tissue, along with constitutional genomic DNA from blood. Expanded whole exome sequencing (WES) was performed on normal/tumor pairs and RNA-seq from tumors for each case. Bioinformatics analysis was performed using industry standard methods for somatic characterization.

Results: All germline mutations were confirmed by WES. Somatic mutational analysis and copy number profiling from WES revealed the greatest similarities among BRCA1 and CHEK2 carriers. As expected, TP53 mutations were found in 8 of 9 BRCA1 carriers as all were triple negative subtype. We also detected somatic TP53 mutations in tumors from 4 of 7 CHEK2 carriers. Somatic TP53 mutations were found in only 1 of 7 BRCA2 tumors and 1 of 4 PALB2 tumors tested. Furthermore, BRCA1 and CHEK2 tumors showed trends of having higher mutation burden. Analysis of copy number BRCAness demonstrated stronger similarities between BRCA1, ATM, CHEK2, and PALB2 tumors. BRCA2 tumors were unique with fewer events and characterized by specific amplifications including 11q23 (CCND1) and 17q23 (BRIP1). Hierarchical clustering of RNA-seq data revealed strong clustering of BRCA1 tumors compared to all other tumors, predominantly attributed to breast cancer subtype. Furthermore, pathway analysis of genes that distinguish BRCA1 mutation positive versus non-BRCA mutated tumors showed strong correlation to pro-inflammatory and immune pathway signatures.

Conclusions: Molecular analysis of 44 breast cancers from individuals with inherited predisposition to breast cancer via BRCA1, BRCA2, ATM, CHEK2, and PALB2 germline mutations demonstrated strongest somatic similarities between BRCA1 and CHEK2 tumors although all BRCA1 were TNBC and all CHEK2 tumors were ER positive. Marked differential gene expression differences in RNA expression patterns were observed in BRCA1 mutation carriers compared with all other groups analyzed. Our study is among the first to interrogate the profile of non-BRCA mutated hereditary breast cancers.

Citation Format: Blum JL, Wong S, Pearson EJ, Nair A, Snipes GJ, Briones N, Baker A, Cropp CD, Carpten JD. Molecular analysis of breast cancers from individuals with hereditary cancer syndromes secondary to mutations in BRCA1, BRCA2, ATM, CHEK2, and PALB2 [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-04-02.

Isolation of bacteriophages from air using vacuum filtration technique: an improved and novel method

AIM

Development of a simple and economical air sampler for isolation and enrichment of bacteriophages from air samples.

METHODS AND RESULTS

A vacuum filtration unit with simple modifications was used for isolation of bacteriophages from air sampled in the lavatory. Air was sampled at the rate of 62 l min^-1 by bubbling into Mcllvaine buffer for 30 min, which was used as bacteriophage solution for enrichment and plaque assessment against individual hosts. Alternatively, the aforementioned phage solution was enriched using a host consortium before plaque assessment. Phages were isolated in the range of 1-12 PFU per ml by the first method, whereas enrichment with host consortium gave phages around 10- to 1000-folds higher in number. Combining with established enrichment method, an improvement of about 10 times in phage isolation efficiency was attained.

CONCLUSIONS

The method is very useful for studying the natural bacteriophages of air, requiring only a basic microbiological laboratory setup making it simple and economical.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study brings out a simple, economical air sampler for assessing air bacteriophages that can be employed by any microbial laboratory. Although various methods are available for studying bacteriophages in water and soil, very limited are available for air. To the best of our knowledge, the method developed in this study is unique in its design and concept for studying bacteriophages in air. The sampler is sterilizable by autoclaving and maintains a healthy rate of airflow provided by conventional vacuum pumps. The use of a nonspecific 'trapping solution' allows for the qualitative and quantitative study of air bacteriophages.

The influence of inspiratory effort and emphysema on pulmonary nodule volumetry reproducibility

AIM

To evaluate the impact of inspiratory effort and emphysema on reproducibility of pulmonary nodule volumetry.

MATERIALS AND METHODS

Eighty-eight nodules in 24 patients with emphysema were studied retrospectively. All patients had undergone volumetric inspiratory and end-expiratory thoracic computed tomography (CT) for consideration of bronchoscopic lung volume reduction. Inspiratory and expiratory nodule volumes were measured using commercially available software. Local emphysema extent was established by analysing a segmentation area extended circumferentially around each nodule (quantified as percent of lung with density of -950 HU or less). Lung volumes were established using the same software. Differences in inspiratory and expiratory nodule volumes were illustrated using the Bland-Altman test. The influences of percentage reduction in lung volume at expiration, local emphysema extent, and nodule size on nodule volume variability were tested with multiple linear regression.

RESULTS

The majority of nodules (59/88 [67%]) showed an increased volume at expiration. Mean difference in nodule volume between expiration and inspiration was +7.5% (95% confidence interval: -24.1, 39.1%). No relationships were demonstrated between nodule volume variability and emphysema extent, degree of expiration, or nodule size.

CONCLUSION

Expiration causes a modest increase in volumetry-derived nodule volumes; however, the effect is unpredictable. Local emphysema extent had no significant effect on volume variability in the present cohort.

Chronic Colovesical Fistula Leading to Chronic Urinary Tract Infection Resulting in End-Stage Renal Disease in a Chronic Granulomatous Disease Patient

A 46-year old man with X-linked chronic granulomatous disease (CGD) being followed at the National Institute of Health with uncontrolled CGD colitis who developed chronic colovesical fistula, and end-stage renal disease (ESRD). Despite aggressive medical management of symptoms with immunomodulators and antibiotic prophylaxis, the chronic colovesical fistula led to chronic pyelonephritis, recurrent urinary tract infections, persistent air in the collecting system and bladder, and post-renal obstruction resulting in renal failure. Patient is now hemodialysis dependent and required diverting loop ileostomy placement. This report highlights multiple potential etiologies of rising serum creatinine in patients with CGD.

Membrane filtration immobilization technique-a simple and novel method for primary isolation and enrichment of bacteriophages

AIM

To develop a method for the isolation and enrichment of bacteriophages selectively against specific bacteria coupled with a membrane filtration technique.

METHODS AND RESULTS

Rapid isolation and concentration of host-specific bacteriophages was achieved by exposure of the sample suspected to contain bacteriophages to a specific host immobilized on a 0·45 μm membrane in a membrane filtration unit. The principle behind this method is the exploitation of host-specific interaction of bacteriophages with their host and maximizing this interaction using a classic membrane filtration method. This provides a chance for each bacteriophage in the sample to interact with the specific host on the membrane filter fitted with a vacuum pump. Specific bacteriophages of the host are retained on the membrane along with its host cells due to the effect of adsorption and these adsorbed bacteriophages (along with their hosts) on the filter disc are then amplified and enriched in regular nutritive broth tryptose soya broth by incubation. With the help of the plaque assay method, host-specific phages of various bacterial species were isolated, segregated and enriched.

CONCLUSIONS

The phage concentration method coupled with membrane filtration immobilization of host bacteria was able to isolate and enrich the host-specific bacteriophages by several fold using a lower quantity of an environmental water sample, or other phage suspensions. Enrichment of phages from single plaques was also achieved.

SIGNIFICANCE AND IMPACT OF THE STUDY

The isolation and detection of host-specific bacteriophages from a low density bacteriophage water sample in a single step by the use of a simple and basic microbiological technique can be achieved. Enrichment of phages from low phage titre suspensions is also achieved very effectively.