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1.
Radiography (Lond) ; 29(4): 807-811, 2023 07.
Article in English | MEDLINE | ID: mdl-37271013

ABSTRACT

INTRODUCTION: Open Reduction and Internal Fixation (ORIF) with volar locking plates are commonly used to manage distal radial fractures. The anatomical tilt lateral (ATL) wrist X-ray is often required for evaluation of intra-articular screw penetration due to the screw position. This study aims to evaluate the correlation between the tube angulation given by performing radiographers for the ATL projection and the post-examination measurement of radial inclination (RI) on the Posterior Anterior (PA) wrist image. METHODS: A retrospective review was performed for 36 patients. A standardised method developed by Kreder et al. (1996) was used to measure the RI on the PA wrist image. All ATL images sent into Picture Archiving and Communications System (PACS) have the tube angulation applied annotated on the image. Pearson's correlation was used to analyse the co-relationship between the RI and the tube angle applied for ATL projection. RESULTS: The average angle of RI measured by the four observers was 19. Normality of 0.385 was established. A positive correlation (p = 0.792) between the RI and the tube angle applied for ATL was found. CONCLUSION: Our study found a strong positive correlation between the tube angulation applied by performing radiographers for the ATL projection and the post-examination RI measured on the PA wrist image by the independent reviewers. This suggests that radiographers can use the measured RI to apply the tube angulation when performing the ATL wrist X-ray, instead of estimating the tube angulation to be applied. IMPLICATIONS FOR PRACTICE: Using the measured RI to apply the tube angulation when performing the ATL wrist X-ray will ensure a more reliable and reproducible way that could reduce the number of repeated images and, thus, unnecessary radiation dose to patients.


Subject(s)
Radius Fractures , Wrist , Humans , X-Rays , Radius Fractures/surgery , Fracture Fixation, Internal/methods , Bone Plates
2.
Radiography (Lond) ; 28(2): 407-411, 2022 05.
Article in English | MEDLINE | ID: mdl-34838437

ABSTRACT

INTRODUCTION: The current technique of angulating for a skyline knee projection relies heavily on the radiographer's estimation of the patella tilt, rendering it subjective and prone to errors. This study therefore aims to (i) examine the correlation between angle ABC measured on the lateral X-ray image and skyline angulation (measured in degrees) and (ii) determine the inter-rater reliability of angle ABC measurements. METHODS: 145 sets of lateral and skyline X-ray images from patients aged 40-70 years old were retrospectively analysed. Angle ABC was measured using prominent landmarks such as the trochlear sulcus, tibial tuberosity and the anterior border of the patella on the lateral knee radiograph. It was then retrospectively compared with the skyline tube angulations to identify any correlation between the two. An inter-rater reliability test was also conducted using the intraclass correlation coefficient (ICC) to determine the reproducibility of the measurement method. RESULTS: A weak correlation was found between angle ABC and skyline angulation (r = 0.1, p = 0.25). The proposed method of measurement shows good inter-rater reliability (ICC = 0.81, 95% CI: 0.77 to 0.84). CONCLUSION: There is insufficient evidence to indicate a correlation between angle ABC and skyline angulation. However, angle ABC can be reliably measured, implying the replicability of the measurement method for other purposes. IMPLICATIONS FOR PRACTICE: The proposed measurement method of angle ABC on the lateral view could have future applications in other areas such as in the measurement of patellofemoral alignment and trochlear morphology.


Subject(s)
Knee Joint , Patella , Adult , Aged , Humans , Knee , Knee Joint/diagnostic imaging , Middle Aged , Patella/diagnostic imaging , Reproducibility of Results , Retrospective Studies
3.
Radiography (Lond) ; 27(3): 873-876, 2021 08.
Article in English | MEDLINE | ID: mdl-33678541

ABSTRACT

INTRODUCTION: A chest X-ray (CXR), taken in full inspiration, is important to ensure pathology in the lungs will not be missed. To achieve this, effective communication on breathing instructions for patients is crucial. During the COVID-19 pandemic, radiographers in Sengkang General Hospital (SKH) were challenged when performing CXR for the patients whose native language is not English. Most of these patients were foreign workers living in the same dormitory which had formed the largest COVID-19 cluster in Singapore. These dormitory residents found it difficult to understand and adhere to breathing instructions, resulting in a suboptimal degree of inspiration when the CXRs were taken. This may ultimately affect the diagnostic value of the radiographs. This paper aims to share and evaluate how radiographers tackled this issue and continued to acquire fully-inspired CXR for the dormitory residents despite the language barrier. METHODS: Using a combination of online survey and retrospective analysis of the rejection rates of CXR done over the period of early April to early June, a team of radiographers evaluated the effectiveness of using audio recordings in managing the issue of not achieving a fully inspired CXR for patients due to language barrier. RESULTS: The rejection rate for CXR due to suboptimal inspiration decreased from 26% to 9% upon implementation of the audio recordings. 92.3% of the CXRs taken within this period also fulfilled the criteria of a fully-inspired CXR, as evidenced by having at least 9 posterior ribs seen above the right hemi-diaphragm. Survey results found a fairly balanced number of radiographers who agreed and disagreed that a fully-inspired CXR was achieved for most of their patients after utilisation of translation manuals and audio recordings. CONCLUSION: After the implementation of audio recordings, the decrease in rejection rate of CXR and an audit which demonstrated that CXR quality was upheld had proven that the radiographers successfully achieved fully-inspired CXR for suspected COVID-19 patients. This confirmed that using pre-recorded audio instructions was an efficient intervention albeit being a one-way communication, leads to more accurate imaging results, aligning with existing literature on communication experiences between radiographers and patients. Moreover, the decreased rejection rate of CXRs had increased department efficiency consequently reducing departmental expenses in the long run. IMPLICATIONS OF PRACTICE: Given that we have an ageing population and the vast majority of the elderly converse in their various dialects, positive feedback from radiographers presented opportunities to expand the translation manual and audio recordings to include local dialects. These can be seamlessly integrated in CXR and other procedures in the hospital setting. To ensure that the translations are culturally sensitive, attention should be paid to the translation process of instructions into other languages and local dialects by enlisting the help of native speakers.


Subject(s)
Allied Health Personnel , COVID-19/diagnostic imaging , Health Communication/methods , Language , Radiography, Thoracic/methods , Humans , Lung/diagnostic imaging , Multilingualism , Pandemics , Retrospective Studies , SARS-CoV-2 , Singapore
4.
Radiography (Lond) ; 27(1): 48-53, 2021 02.
Article in English | MEDLINE | ID: mdl-32517970

ABSTRACT

INTRODUCTION: With the current Covid-19 pandemic, general wards have been converted into cohort wards for Covid-19 patients who are stable and ambulant. A 2-radiographer mobile radiography team is required to perform bedside Chest X-rays (CXR) for these patients. Hospital guidelines require both radiographers to be in full Personal Protective Equipment (PPE) throughout the image acquisition process and the mobile radiographic unit needs to be disinfected twice after each case. This affects the efficiency of the procedure and an increase usage of limited PPE resources. This study aims to explore the feasibility of performing mobile chest radiography with the mobile radiographic unit in a "clean" zone of the hospital ward. METHODS: An anthropomorphic body phantom was used during the test. With the mobile radiographic unit placed in a "clean" zone, the phantom and the mobile radiographic unit was segregated by the room door with a clear glass panel. The test was carried out with the room door open and closed. Integrated radiation level and patient dose were measured. A consultant radiologist was invited to review and score all the images acquired using a Barco Medical Grade workstation. The Absolute Visual Grading Analysis (VGA) scoring system was used to score these images. RESULTS: A VGA score of 4 was given to all the 40 test images, suggesting that there is no significant differences in the image quality of the images acquired using the 2 different methods. Radiation exposure received by the patient at the highest kV setting through the glass is comparable to the regular CXR on patient without glass panel at 90 kV, suggesting that there is no significant increase in patient dose. CONCLUSION: The result suggests that acquiring CXR with the X-ray beam attenuating through a glass panel is a safe and feasible way of performing CXR for COVID-19 patients in the newly converted COVID wards. This will allow the mobile radiographic unit as well as one radiographer to be completely segregated from the patient. IMPLICATIONS FOR PRACTICE: This new method of acquiring CXR in an isolation facility set up requires a 2-Radiographer mobile radiography team, and is applicable only for patients who are generally well and not presented with any mobility issues. It is also important to note that a clear glass panel must be present in the barriers set up for segregation between the "clean" zone and patient zone in order to use this new method of acquiring CXR.


Subject(s)
COVID-19/diagnosis , COVID-19/prevention & control , Patients' Rooms/organization & administration , Radiography, Thoracic/methods , Radiology Department, Hospital/organization & administration , Feasibility Studies , Humans , Phantoms, Imaging , Radiation Dosage
5.
Radiography (Lond) ; 27(1): 43-47, 2021 02.
Article in English | MEDLINE | ID: mdl-32540250

ABSTRACT

INTRODUCTION: The value of combined blended and experiential learning on radiographer diagnostic comment has not been explored. This study aims to examine the accuracy of image interpretation comment of radiographers who received a period of blended and experiential learning in Radiographer Abnormality Detection Systems (RADS). METHODS: We evaluated the diagnostic opinions of 13 radiographers who received a blended training and experiential learning (a process of self-learning and reflection) in RADS. Radiographers' opinions on 16,483 images were examined using the final radiologists' report as a reference standard. For each radiographer, we recorded the number of true positive, true negative, false positive and false negative opinions and MedCal® was used to calculate diagnostic performance and error rates. A t-test was used to assess whether the number of images read was associated with performance and whether the radiographers retained performance over time. RESULTS: Sensitivity ranged from 87.4 (84.0-90.2) to 98.9 (97.5-99.7) with a mean of 94.3 (93.6-94.8). Specificity varied from 96.4 (94.8-97.5) to 99.9 (99.41-100.0) with a mean of 98.2 (97.9-98.4). Diagnostic accuracy ranged from 93.1 (91.5-94.4) to 99.5 (98.9-99.8) with a mean of 96.9 (96.6-97.1). The mean false positive rate was 0.018 (range: 0.010-0.031) with a false negative rate of 0.057 (range: 0.026-0.11). There were no differences in performance between the first and latter nine months of providing opinions and the number of images reviewed was not associated with performance. CONCLUSION: Radiographers who received blended and experiential learning in RADS provide accurate diagnostic comments on plain emergency appendicular skeleton radiographs. IMPLICATION FOR PRACTICE: A combined blended and experiential learning can equip radiographers to provide diagnostic opinion on plain appendicular skeleton radiographs.


Subject(s)
Clinical Competence , Skeleton , Humans , Radiography , Singapore , X-Rays
7.
J Hosp Infect ; 105(2): 252-257, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32112827

ABSTRACT

BACKGROUND: Heater-cooler units (HCUs) have been implicated in the recent global outbreak of invasive Mycobacterium chimaera infection among patients following cardiothoracic surgery. Because infected patients tend to remain asymptomatic for extended periods, detection of M. chimaera from HCUs in real time is essential to halting the ongoing M. chimaera HCU-associated outbreak. Sample collection protocols to evaluate the presence of M. chimaera offer conflicting recommendations regarding the addition of sodium thiosulfate (NaT) during the collection process. AIM: To study the effect of NaT on M. chimaera recovery and culture contamination. METHODS: Seventy-six paired HCU water samples (with and without NaT) were collected, processed and cultured simultaneously into Lowenstein-Jensen slants, Middlebrook 7H10 agar plates, and mycobacterial growth indicator tubes (MGITs), and incubated at 37°C. A subset of 31 paired samples was additionally cultured on MGITs and incubated at 30°C. FINDINGS: Of 76 samples incubated at 37°C in each of the three media, with and without NaT, M. chimaera was identified in at least one aliquot of 21 samples. CONCLUSION: The presence of NaT did not significantly increase the probability of recovering M. chimaera in a multi-variable conditional logistic model and culture contamination rates were similar between aliquots with and without NaT. In the subset of samples cultured on MGITs at both 30°C and 37°C, the presence of NaT again was not associated with M. chimaera recovery, but was significantly associated with reduced culture contamination.


Subject(s)
Equipment Contamination , Mycobacterium Infections/prevention & control , Mycobacterium/drug effects , Thiosulfates/pharmacology , Water Microbiology , Cardiac Surgical Procedures/adverse effects , Colony Count, Microbial , Disease Outbreaks/prevention & control , Heating/instrumentation , Humans , Mycobacterium/isolation & purification , Selection Bias , Water , Water Supply
8.
Int J Tuberc Lung Dis ; 21(5): 544-549, 2017 05 01.
Article in English | MEDLINE | ID: mdl-28303781

ABSTRACT

BACKGROUND: Diagnostic and treatment delays increase the severity and transmission of pulmonary tuberculosis (PTB). This study aimed to evaluate TB diagnostic and treatment delays in acid-fast bacilli (AFB) smear-negative patients. METHODS: This was a retrospective observational study. Patients with positive AFB culture of Mycobacterium tuberculosis complex (MTC) were selected from among hospitalised patients with a diagnosis of pneumonia. Admission ward, anti-tuberculosis treatment and the duration of AFB culture were compared between smear-positive and smear-negative patients. RESULTS: Of the 70 patients with positive isolation of MTC in AFB culture, 27 (38.5%) were smear-negative; of these, 18 (66.7%) were not isolated while in hospital, and 17 (63%) were neither diagnosed nor treated for TB. In contrast, 41 of the 43 smear-positive patients (95.3%) were directly admitted or quickly transferred to the isolation room and started on anti-tuberculosis treatment (P < 0.001). Samples from smear-negative patients required more time to grow MTC in AFB culture than those of smear-positive patients (23 days vs. 14 days, P < 0.001). Diabetes was significantly associated with AFB smear positivity, with an odds ratio of 12.2. CONCLUSIONS: Negative AFB smears caused significant diagnostic and treatment delay. Patients staying in the general ward were exposed to TB patients who were not diagnosed in time.


Subject(s)
Mycobacterium tuberculosis/isolation & purification , Pneumonia/diagnosis , Sputum/microbiology , Tuberculosis, Pulmonary/diagnosis , Aged , Delayed Diagnosis , Female , Hospitalization , Humans , Male , Middle Aged , Patient Isolation , Pneumonia/microbiology , Retrospective Studies , Severity of Illness Index , Time Factors , Time-to-Treatment , Tuberculosis, Pulmonary/microbiology , Tuberculosis, Pulmonary/transmission
9.
Clin Microbiol Infect ; 21(3): 236-41, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25658536

ABSTRACT

Nontuberculous mycobacteria infection is a growing global concern, but data from Asia are limited. This study aimed to describe the distribution and antibiotic susceptibility profiles of rapidly growing mycobacterium (RGM) isolates in Singapore. Clinical RGM isolates with antibiotic susceptibility tests performed between 2006 and 2011 were identified using microbiology laboratory databases and minimum inhibitory concentrations of amikacin, cefoxitin, clarithromycin, ciprofloxacin, doxycycline, imipenem, linezolid, moxifloxacin, sulfamethoxazole or trimethoprim-sulfamethoxazole, tigecycline and tobramycin were recorded. Regression analysis was performed to detect changes in antibiotic susceptibility patterns over time. A total of 427 isolates were included. Of these, 277 (65%) were from respiratory specimens, 42 (10%) were related to skin and soft tissue infections and 36 (8%) were recovered from blood specimens. The two most common species identified were Mycobacterium abscessus (73%) and Mycobacterium fortuitum group (22%), with amikacin and clarithromycin being most active against the former, and quinolones and trimethoprim-sulfamethoxazole against the latter. Decreases in susceptibility of M. abscessus to linezolid by 8.8% per year (p 0.001), M. fortuitum group to imipenem by 9.5% per year (p 0.023) and clarithromycin by 4.7% per year (p 0.033) were observed. M. abscessus in respiratory specimens is the most common RGM identified in Singapore. Antibiotic options for treatment of RGM infections are increasingly limited.


Subject(s)
Mycobacterium Infections/epidemiology , Mycobacterium Infections/microbiology , Mycobacterium , Anti-Bacterial Agents/pharmacology , Cohort Studies , Drug Resistance, Bacterial , History, 21st Century , Humans , Microbial Sensitivity Tests , Mycobacterium/classification , Mycobacterium/drug effects , Mycobacterium/genetics , Mycobacterium/isolation & purification , Mycobacterium Infections/history , Singapore/epidemiology
10.
Zoonoses Public Health ; 56(4): 206-8, 2009 May.
Article in English | MEDLINE | ID: mdl-19309483

ABSTRACT

We describe three zoonotic streptococcal soft tissue infections resulting from fresh seafood contact. One was a localized thumb infection with Streptococcus iniae in an immunocompetent healthy young male resulting from a puncture wound from a crab pincer. The other two were cases of ascending upper limb cellulitis associated with bacteraemia in mastectomy patients. One of these infections was caused by S. iniae while the other was caused by Streptococcus dysgalactiae subsp. dysgalactiae, a species that has not been previously described as a cause of zoonotic infection. Hence when cleaning raw seafood, protective equipment should be used to minimize the risk of percutaneous injuries.


Subject(s)
Cellulitis/microbiology , Food Handling , Seafood/microbiology , Streptococcal Infections/microbiology , Streptococcal Infections/transmission , Aged , Animals , Anti-Bacterial Agents/therapeutic use , Cellulitis/drug therapy , China , Female , Humans , Male , Mastectomy, Modified Radical , Middle Aged , Streptococcal Infections/drug therapy , Streptococcus/isolation & purification , Young Adult , Zoonoses/microbiology , Zoonoses/transmission
11.
Ann Acad Med Singap ; 34(1): 137-40, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15726234

ABSTRACT

INTRODUCTION: The accuracy and practicality of PCR-restriction endonuclease analysis (PRA) for rapid identification of pathogenic rapidly growing mycobacteria (RGM) isolates were evaluated. MATERIALS AND METHOD: PRA identification using an amplified 439-bp segment (amplicon) of the 65-kDa heat shock protein gene was compared to identification by conventional methods, for 39 clinically significant RGM isolates. RESULTS: The accuracy of PRA in the identification of RGM isolates was comparable to that of conventional methods. Moreover, PRA was able to identify RGM faster, within 2 to 3 working days compared to conventional methods which require 2 to 4 weeks to perform and complete different tests. CONCLUSION: PRA methodology could be easily incorporated into the clinical laboratory setting. This would be beneficial for the management of patients with infections due to pathogenic RGM.


Subject(s)
Bacterial Proteins/genetics , Mycobacterium/classification , Polymerase Chain Reaction/methods , Chaperonin 60 , Chaperonins/genetics , Genes, Bacterial/genetics , Humans , In Vitro Techniques , Mycobacterium/genetics , Mycobacterium/growth & development , Mycobacterium Infections/microbiology , Reproducibility of Results
12.
J Clin Microbiol ; 42(7): 3336-8, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15243110

ABSTRACT

PCR-restriction endonuclease analysis (PRA) was used for direct identification of Mycobacterium haemophilum in clinical specimens from immunocompromised patients. PRA correctly identified M. haemophilum in four smear-positive specimens. Direct identification by PRA takes 2 to 3 working days compared to the 3 to 5 weeks required for culture isolation and identification by conventional methods.


Subject(s)
Mycobacterium haemophilum/isolation & purification , Polymerase Chain Reaction/methods , Skin/microbiology , DNA Restriction Enzymes/pharmacology , Humans , Immunocompromised Host , Skin/injuries
13.
Ann Acad Med Singap ; 33(3): 385-8, 2004 May.
Article in English | MEDLINE | ID: mdl-15175788

ABSTRACT

INTRODUCTION: Septic ovarian venous thrombosis is an uncommon condition. Diagnosis is often not immediately apparent clinically and there are many that mimic this condition. We described an unusual case of septic ovarian vein thrombosis associated with Campylobacter fetus (C. fetus) bacteraemia. CLINICAL PICTURE: A 46-year-old female presented with fever and acute right loin pain. Right ovarian venous thrombosis was demonstrated on sonography and confirmed with computed tomography and magnetic resonance imaging. C. fetus was isolated from the blood. TREATMENT AND OUTCOME: The patient was given antibiotics and anticoagulation therapy with good response. CONCLUSION: Septic ovarian vein thrombosis should be considered as a differential diagnosis in female patients presenting with fever associated with lower abdominal pain. C. fetus bacteraemia also predisposes to thrombophlebitis, including septic ovarian vein thrombosis. When they are diagnosed in a timely manner and treated appropriately, the response is good and potential serious complications, including thromboembolism, and death could be averted. Radiological imaging is useful in the diagnostic work-up of this condition.


Subject(s)
Bacteremia/complications , Campylobacter Infections/complications , Campylobacter fetus , Ovary/blood supply , Venous Thrombosis/etiology , Female , Fever/etiology , Humans , Middle Aged , Tomography, X-Ray Computed , Ultrasonography, Doppler, Duplex , Venous Thrombosis/diagnostic imaging
14.
J Med Microbiol ; 53(Pt 1): 57-59, 2004 Jan.
Article in English | MEDLINE | ID: mdl-14663106

ABSTRACT

The BD ProbeTec ET system for identification of Mycobacterium tuberculosis complex (MTBC) isolates from BACTEC 12B culture vials was evaluated in comparison with BACTEC NAP (p-nitro-alpha-acetylamino-beta-hydroxy-propiophenone) differentiation. Of 145 mycobacterial isolates tested, comprising 89 MTBC and 56 non-tuberculous mycobacteria (NTM), BD ProbeTec ET correctly identified 87 MTBC and 56 NTM but missed two MTBC. Three NTM were misidentified when NAP was incubated at 37 degrees C only. Overall sensitivity, specificity and positive and negative predictive values were respectively 97.8, 100, 100 and 96.6 % for the BD ProbeTec ET system and 100, 94.6, 96.7 and 94.6 % for NAP.


Subject(s)
Bacteriological Techniques/methods , Mycobacterium tuberculosis/isolation & purification , Tuberculosis/microbiology , Bacteriological Techniques/standards , Humans , Predictive Value of Tests , Sensitivity and Specificity , Time Factors , Tuberculosis/diagnosis
16.
Ann Acad Med Singap ; 29(5): 673-7, 2000 Sep.
Article in English | MEDLINE | ID: mdl-11126708

ABSTRACT

INTRODUCTION: Coagulase-negative staphylococci, commonly Staphylococcus epidermidis, cause 5% of native valve endocarditis. We describe a case due to Staphylococcus lugdunensis, a coagulase-negative staphylococcus identified in 1988, as a first report in Southeast Asia. It was previously misidentified as S. aureus because it is sometimes slide coagulase positive, but always tube coagulase negative, resulting in its delayed recognition as a pathogen. We also reviewed 36 other cases reported in the English literature from 1988 to 1999. CLINICAL PICTURE: Our patient was admitted 3 times over 4 months for unresolved weight loss and fever before the coagulase-negative staphylococcus bacteraemia was eventually considered significant. TREATMENT AND OUTCOME: He was treated with 4 weeks of high-dose intravenous penicillin and 2 weeks of gentamicin and did not require urgent valve replacement. CONCLUSION: A positive blood culture of coagulase-negative staphylococcus is not always a contaminant. S. lugdunensis can cause aggressive native valve endocarditis resulting in high mortality, especially without surgical intervention.


Subject(s)
Endocarditis, Bacterial/microbiology , Staphylococcal Infections , Adult , Bacteremia/microbiology , Coagulase , Endocarditis, Bacterial/diagnosis , Endocarditis, Bacterial/drug therapy , Humans , Male , Singapore , Staphylococcal Infections/diagnosis , Staphylococcal Infections/drug therapy , Staphylococcal Infections/microbiology , Staphylococcus/isolation & purification
18.
Pathology ; 30(4): 395-8, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9839316

ABSTRACT

The prevalence of penicillin-resistant Streptococcus pneumoniae in clinical isolates from the Pathology Department of the Singapore General Hospital, in 1995, was 25%. Most of the resistant isolates belonged to serogroup 19 and were resistant to multiple antibiotics. Field-inversion gel electrophoresis (FIGE), after chromosomal digestion with the restriction enzymes Apal and Smal, was performed on all isolates of multiresistant serogroup 19 S. pneumoniae so as to determine whether they were of clonal origin. Twenty-six isolates, including six controls, were studied. Analysis of the FIGE patterns revealed three distinct clusters of closely related strains. The predominant clone comprised ten isolates of multiresistant serogroup 19 S. pneumoniae and also included two controls of a different serogroup. The presence of multiresistant serogroup 19 S. pneumoniae in Singapore, appears to be due to the spread of a small number of clones.


Subject(s)
Bacterial Typing Techniques , DNA, Bacterial/analysis , Drug Resistance, Multiple , Penicillin Resistance/genetics , Pneumococcal Infections/microbiology , Streptococcus pneumoniae/classification , Adult , Aged , Child , Child, Preschool , DNA Fingerprinting , Electrophoresis, Capillary , Erythromycin/pharmacology , Humans , Infant , Microbial Sensitivity Tests , Middle Aged , Pneumococcal Infections/drug therapy , Pneumococcal Infections/epidemiology , Serotyping , Singapore/epidemiology , Streptococcus pneumoniae/drug effects , Streptococcus pneumoniae/genetics , Tetracycline/pharmacology , Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology
19.
Am J Clin Pathol ; 109(4): 399-403, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9535392

ABSTRACT

Bacteremia due to a vancomycin-dependent enterococcus (VDE) occurred during long-term vancomycin therapy in a renal transplant recipient with underlying pancreatitis and a vancomycin-resistant enterococcal (VRE) wound infection and bacteremia. The VDE was isolated from blood during vancomycin therapy and grew only in the presence of vancomycin and D-alanine-D-alanine (DADA), a substance required for cell-wall synthesis. Colonies beyond the periphery of growth of the VDE around a vancomycin disk contained vancomycin-independent revertant mutants after 48 hours of incubation. Pulsed-field gel electrophoresis of the VDE, revertant mutant, the initial blood culture isolate of VRE, and an autopsy isolate showed that the four strains were identical. Antimicrobial susceptibility testing was performed using standard macrobroth and microbroth dilution methods. DADA was used as a growth supplement for macrobroth dilution susceptibility testing of the VDE isolate. Minimum inhibitory concentrations (MICs) were similar for the VRE isolate and the VDE revertant, which were both resistant to ampicillin, high-level gentamicin, ciprofloxacin, imipenem, vancomycin, and daptomycin, and were susceptible to fusidic acid, high-level streptomycin, rifampin, and a quinupristin-dalfopristin combination. The MICs of teicoplanin were 2 microg/mL or less and 16 microg/mL for the clinical VRE isolate and the VDE revertant, respectively. The autopsy isolate was resistant to all antimicrobials tested and showed a fourfold increase in MICs for quinupristin-dalfopristin compared with that of the original blood isolate. The VDE was susceptible to all drugs tested except vancomycin.


Subject(s)
Alanine/physiology , Drug Resistance, Microbial , Enterococcus/isolation & purification , Vancomycin/pharmacology , Anti-Bacterial Agents/pharmacology , Electrophoresis, Gel, Pulsed-Field , Enterococcus/genetics , Humans , Microbial Sensitivity Tests
20.
Ann Acad Med Singap ; 25(2): 179-83, 1996 Mar.
Article in English | MEDLINE | ID: mdl-8799001

ABSTRACT

Acinetobacter baumannii has recently emerged as an important nosocomial pathogen because of its resistance to the majority of commonly used antimicrobial agents. Therefore, the pattern of isolation of Acinetobacter baumannii in our laboratory and the in vitro susceptibilities to various antimicrobial agents were studied. One hundred and two clinical isolates of previously identified Acinetobacter calcoaceticus var. anitratus from different patients were collected from the Diagnostic Bacteriology section of the Department of Pathology, Singapore General Hospital. The strains were reclassified according to recent taxonomic changes using phenotypic tests and tested for beta-lactamase production using Cefinase disks. In vitro sensitivities to various antimicrobial agents were determined using the disk diffusion method. Of the 103 A. calcoaceticus var. anitratus species, 99 were identified as A. baumannii, 2 as A. junii and 1 as A. haemolyticus. Majority of the A. baumannii isolates were from wound sites (63.6%) and from patients in the general wards (70.7%). beta-lactamase activity was present in all these isolates. The most active agent against all A. baumannii isolates was imipenem. However, 14 of the strains were resistant to imipenem, 8 of which came from the burns ward. Two-thirds of isolates from burn patients were completely resistant to all the antimicrobial agents tested. Almost all isolates previously identified as A. calcoaceticus var. anitratus in our laboratory are A. baumannii strains. Imipenem is the most effective antimicrobial agent; however, the high rate of imipenem resistance especially among burn patients is a source of major concern.


Subject(s)
Acinetobacter calcoaceticus/drug effects , Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple , beta-Lactamases/metabolism , Acinetobacter calcoaceticus/enzymology , Colony Count, Microbial , Humans , Imipenem/pharmacology , Microbial Sensitivity Tests/trends , Thienamycins/pharmacology
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