Ultrasound Gel as a Source of Hospital Outbreaks: Indian Experience and Literature Review

Purpose: Hospital outbreaks are observed increasingly worldwide with various organisms from different sources such as contaminated ultrasound gel, intravenous (IV) fluids and IV medications. Among these, ultrasound gel is one of the most commonly reported sources for Burkholderia cepacia complex (Bcc) outbreaks. In this study, we describe our experience on investigation and the management of Bcc bacteraemia outbreak due to contaminated ultrasound gel from a tertiary care centre, South India. Materials and Methods: Over a 10-day period in October 2016, seven children in our Paediatric intensive care unit (ICU) were found to have bacteraemia with Bcc isolated from their blood culture. Repeated isolation of the same organism with similar antimicrobial susceptibility pattern over a short incubation period from the same location, confirmed the outbreak. An active outbreak investigation, including environmental surveillance, was carried out to find the source and control the outbreak. Isolates were subjected to multi-locus sequence typing (MLST) and global eBURST (goeBURST) analysis. Results: Environmental surveillance revealed contaminated ultrasound gel as the source of infection. MLST and goeBURST analysis confirmed that the outbreak was caused by a novel sequence type 1362 with the same clonal complex CC517. The outbreak was controlled by stringent infection control measures, withdrawal of contaminated ultrasound gel from regular usage and implementing the practice of using ultrasonogram (USG) probe cover for USG screening and guided procedures. Conclusion: This report highlights the importance of early identification of an outbreak, prompt response of the ICU and infection control teams, sound environmental and epidemiological surveillance methods to identify the source and stringent infection control measures to control the outbreak. Contaminated ultrasound gel can be a potential source for healthcare-associated infection, which cannot be overlooked.     

Utility of whole-cell repetitive extragenic palindromic sequence-based PCR (REP-PCR) for the rapid detection of nosocomial outbreaks of multidrug resistant organisms: Experience at a tertiary care center in North India

Background: There is a huge need to develop molecular typing methods which are simple to perform, rapid and cost effective to confirm clonality of nosocomial isolates in outbreak situations. Objectives: The aim of the study was to investigate a hospital outbreak of multi-drug resistant (MDR) Klebsiellapneumoniae septicemia in a paediatric surgery intensive care unit (PSICU) using a repetitive extragenic palindromic polymerase chain reaction (REP-PCR). Materials and Methods: MDR Klebsiella pneumoniae isolates from an outbreak of nosocomial sepsis were typed byREP-PCR using consensus primers. Isolates from different intensive care units (ICUs) but with similar antibiogram were also genotyped for comparison. Results and Conclusion: A cluster of twelve MDR K Pneumoniae septicemia cases was identified at the PSICU by genotyping using REP-PCR. Surveillance cultures failed to pick up any source of infection. REP-PCR was found to be a rapid and simple tool for investigation outbreaks in hospitals. Due to early detection we could initiate infection control practices with focus on hand washing and prevent the further transmission of the organism.     

Molecular Characterisation for Clonality and Transmission Dynamics of an Outbreak of Klebsiella pneumoniae amongst Neonates in a Tertiary Care Centre in South India

Purpose: Sepsis is a significant cause of morbidity and mortality amongst neonates. Klebsiella pneumoniae is a common cause of nosocomial outbreaks causing bacteraemia and having potential of acquiring plasmids enhancing antimicrobial resistance. In the present study, we investigate K. pneumoniae outbreak causing bacteraemia amongst neonates over a span of 2 months. Isolates were characterised for antimicrobial resistance, virulence, molecular typing for clonality and plasmid typing for transmission dynamics, and patient outcome was investigated. Methods: Thirteen isolates of K. pneumoniae were obtained during October–November 2016. Antimicrobial susceptibility testing was performed, and multiplex polymerase chain reaction (PCR) for β-lactamases and PCR for ompK35 and ompK36 were performed. To study hypervirulence, string test and PCR for rmpA and rmpA2 were performed. Multilocus sequence typing and Inc plasmid typing were carried out to study transmission dynamics. Results: Amongst 13 isolates, all isolates harboured bla_SHV and bla_TEM; 12 isolates carried bla_CTX-M-1. ompK35 was present in all, but ompK36 was absent in 12 isolates. Ten isolates belonged to ST48, 6 amongst which contained IncFII (K) plasmid. One isolate each belonged to ST29, ST111 and ST2647 (novel clone). None of the isolates was hypervirulent. Conclusion: Extended-spectrum β-lactamase K. pneumoniae is commonly seen in Indian hospitals and main mechanisms being production of SHV, TEM and CTX-M enzymes as seen in the present study. Outer membrane porins contribute significantly to antimicrobial resistance. Emergence of new clones such as ST2647 implies continuous evolution of the organism and also potential for rapid genetic recombination leading to multidrug resistance. Outbreaks amongst neonates lead to fatal outcome, and stringent hospital infection control is necessary.     

Diagnostic methods and identification challenges experienced in a Burkholderia contaminans outbreak occurred in a tertiary care centre

BackgroundRecently, a novel species contaminans belonging to the family Burkholderia cepacia complex (Bcc) is rising as a hospital pathogen. Detection of Burkholderia contaminans, a member of Bcc can be done only by MALDI TOF and sequencing techniques. We report the diagnostic challenges faced in an outbreak of bacteremia due to B. contaminans grown in diltiazem vials.MethodThe department of microbiology notified the infection control team about a cluster of eleven patients with B. contaminans isolated from blood culture. An outbreak investigation was initiated by performing environmental surveillance and sterility testing of solutions given for the patients. Routine phenotypical methods for identification of species followed by MALDI-TOF and sequencing was performed to identify the pathogen.ResultsAll the patients detected with B. contaminans were having cardiac disease and received diltiazem. Sterility testing of diltiazem vials given for the patient and an unopened vial of same batch has grown B. contaminans. Clonal typing has confirmed the sequence similarities between patient and solution isolates.ConclusionDue to diagnostic challenge in identifying the species of Bcc, MALDI TOF and clonal typing remains the key diagnostic tools available to detect Bcc species at an earliest especially in an outbreak.     

An outbreak of CTX-M-15-producing Klebsiella pneumoniae isolates in an intensive care unit of a teaching hospital in Kuwait

Objective: This study reports an outbreak of Klebsiella pneumoniae infections in 14 patients during a 2-month period (August–September, 2008) in the intensive care unit (ICU) of a teaching hospital in Kuwait. Materials and Methods: The clinical sources were blood (9), urine (3) and respiratory secretions (2) identified by the automated VITEK-2 ID System. Susceptibility testing was performed by the E-test method. Extended-spectrum β-lactamase (ESBL) production was assessed using the ESBL E-test and confirmed by PCR. Carriage of bla genes was determined by PCR and sequence analysis. The transferability of resistance phenotypes was demonstrated by conjugation experiments and clonal relatedness was determined by PFGE. Results: The isolates were susceptible to imipenem, meropenem, and tigecycline and produced ESBL. All isolates yielded an amplicon of 499 bp with universal consensus primers (MA primers). DNA sequence analysis showed that they all harboured bla_CTX-M-15and bla_TEM-1genes. The environmental isolate obtained from a suction machine was also CTX-M-15/TEM-1 producer. The resistance phenotypes were transferrable to the Escherichia coli J53^r strain. PFGE, revealed two clones, A and B, related with a Dice coefficient of >94.1%. A mortality rate of 21.4% was recorded. Conclusion: The outbreak was contained by robust and aggressive infection control measures. This study highlights the first outbreak of CTX-M-15-producing K. pneumoniae associated with high mortality in an adult medical ICU in Kuwait.     

Clonal evolution multi-drug resistant Acinetobacter baumannii by pulsed-field gel electrophoresis

Background: Acinetobacter baumannii is usually multi-drug resistant (MDR), including third generation cephalosporins, amino glycosides and fluoroquinolone. Resistance to these antibiotics is mediated by multiple factors such as: lactamases, efflux pumps and other mechanisms of resistance. Pulsed-field gel electrophoresis (PFGE) was then used to investigate the genetic relationships among the MDR isolates. Aim: The aim of this study was to determine MDR isolates and the existence of OXAs genes among MDR isolates of A. baumannii collected from Kermanshah hospitals in west of Iran. Materials and Methods: Forty-two MDR A. baumannii were collected from patients at Kermanshah hospitals. The isolates were identified by biochemical tests and API 20NE kit. The susceptibility to different antibiotics by disk diffusion method was determined. Polymerase chain reaction (PCR) was performed for detection of bla_OXA-23-like, bla_OXA-24-like, bla_OXA-51-like and bla_OXA-58-like betalactamase genes in isolates and clonal relatedness was done by PFGE (with the restriction enzyme ApaI) and patterns analyzed by Bionumeric software. Results: This study showed high resistant to ciprofloxacin, piperacillin, ceftazidime and also resistant to other anti-microbial agents and more spread blaOXA-23-like gene (93%) in MDR isolate. The PFGE method obtained six clones: A (10), B (9), C (5), D (4), E (11) and F (3) that clone E was outbreak and dominant in different wards of hospitals studied. Conclusion: An isolate from the emergency ward of these hospitals had indistinguishable isolates PFGE profile and similar resistance profile to isolates from intensive care unit (ICU), suggesting likely transmission from ICU to emergency via patient or hospital staff contact.     

<Emphasis Type="Italic">Burkholderia cepacia</Emphasis> complex in Serbian patients with cystic fibrosis: prevalence and molecular epidemiology

The Burkholderia cepacia complex (Bcc) organisms remain significant pathogens in patients with cystic fibrosis (CF). This study was performed to evaluate the prevalence, epidemiological characteristics, and presence of molecular markers associated with virulence and transmissibility of the Bcc strains in the National CF Centre in Belgrade, Serbia. The Bcc isolates collected during the four-year study period (2010–2013) were further examined by 16 s rRNA gene, pulsed-field gel electrophoresis of genomic DNA, multilocus sequence typing analysis, and phylogenetic analysis based on concatenated sequence of seven alleles. Fifty out of 184 patients (27.2 %) were colonized with two Bcc species, B. cenocepacia (n?=?49) and B. stabilis (n?=?1). Thirty-four patients (18.5 %) had chronic colonization. Typing methods revealed a high level of similarity among Bcc isolates, indicating a person-to-person transmission or acquisition from a common source. New sequence types (STs) were identified, and none of the STs with an international distribution were found. One centre-specific ST, B. cenocepacia ST856, was highly dominant and shared by 48/50 (96 %) patients colonized by Bcc. This clone was characterized by PCR positivity for both the B. cepacia epidemic strain marker and cable pilin, and showed close genetic relatedness to the epidemic strain CZ1 (ST32). These results indicate that the impact of Bcc on airway colonization in the Serbian CF population is high and virtually exclusively limited to a single clone of B. cenocepacia. The presence of a highly transmissible clone and probable patient-to-patient spread was observed.     

Detection of 123 bp fragment of insertion element IS6110 Mycobacterium tuberculosis for diagnosis of extrapulmonary tuberculosis

Purpose: Extrapulmonary tuberculosis (EPTB) is emerging problem in developing and developed countries. The diagnosis of EPTB in its different clinical presentations remains a true challenge. IS6110-based polymerase chain reaction (PCR) is used for rapid identification and positivity rate of the Mycobacterium tuberculosis complex in clinical isolates of different sites of EPTB. The present study was carried out to study the prevalence of M. tuberculosis complex in clinical isolates of EPTB at tertiary care centres in Lucknow. Materials and Methods: Seven hundred fifty-six specimens were collected from the suspected cases of EPTB which were processed for Mycobacteria by Ziehl Neelson (ZN) staining and BACTEC culture. All the specimens were also processed for IS6110-based PCR amplification with primers targeting 123 bp fragment of insertion element IS6110 of the M. tuberculosis complex. Results: Of these 756 specimens, 71(9.3%) were positive for acid fast bacilli (AFB) by ZN staining, 227(30.1%) were positive for mycobacteria by BACTEC culture and IS6110 PCR were positive for M. tuberculosis complex in 165 (20.7%) isolates. We found a significant difference in sensitivities of different tests (P<0.05). Conclusions: This study reveals the positivity of M. tuberculosis complex in clinical isolates of EPTB case in tertiary care hospitals in Northern India. 72.7% of M. tuberculosis complex was confirmed by IS6110-PCR in culture isolates from different sites of EPTB. The high prevalence of the M. tuberculosis complex was seen in lymph node aspirate and synovial fluid. However, utility of PCR may play a potentially significant role in strengthening the diagnosis of EPTB especially targeting IS6110.     

A MOLECULAR METHOD FOR TYPING HERPES SIMPLEX VIRUS ISOLATES AS AN ALTERNATIVE TO IMMUNOFLUORESCENCE METHODS

Background: Typing of Herpes simplex virus (HSV) isolates is required to identify the virus isolated in culture. The methods available for this include antigen detection by immunofluorescence (IF) assays and polymerase chain reaction (PCR). This study was undertaken to standardize a molecular method for typing of HSV and compare it with a commercial IF reagent for typing. Objectives: To compare a molecular method for typing HSV isolates with a monoclonal antibody (MAb) based IF test. Study design: This cross-sectional study utilized four reference strains and 42 HSV isolates obtained from patients between September 1998 and September 2004. These were subjected to testing using an MAb-based IF test and a PCR that detects the polymerase (pol) gene of HSV isolates. Results: The observed agreement of the MAb IF assay with the pol PCR was 95.7%. Fifty four point eight percent (23/42) of isolates tested by IF typing were found to be HSV-1, 40.5% (17/42) were HSV-2, and two (4.8%) were untypable using the MAb IF assay. The two untypable isolates were found to be HSV-2 using the pol PCR. In addition, the cost per PCR test for typing is estimated to be around Rs 1,300 (USD 30), whereas the cost per MAb IF test is about Rs 1,500 (USD 35) including all overheads (reagents, instruments, personnel time, and consumables). Conclusion: The pol PCR is a cheaper and more easily reproducible method for typing HSV isolates as compared to the IF test. It could replace the IF-based method for routine typing of HSV isolates as availability of PCR machines (thermal cyclers) is now more widespread than fluorescence microscopes in a country like India.     

An outbreak of methicillin-resistant Staphylococcus aureus infection in patients of a pediatric intensive care unit and high carriage rate among health care workers.

BACKGROUND AND PURPOSE: Methicillin-resistant Staphylococcus aureus (MRSA) has been the leading cause of nosocomial infections in many hospitals. To investigate the impact of carriage by health care workers (HCWs) on patient transmission, surveillance culture was performed following an outbreak of MRSA in a pediatric intensive care unit (PICU). METHODS: Isolates from 61 HCWs and 10 environmental sites were collected. Pulsed-field gel electrophoresis (PFGE) and antibiogram analysis were performed to determine the clonal relationship between isolates and potential routes of transmission. RESULTS: The overall carriage rate of HCWs was 67.2% (41/61) for S. aureus and 26.2% (16/61) for MRSA. One MRSA was isolated from the 10 environmental sites sampled. Two major MRSA clusters were identified based on the PFGE patterns. Isolates with indistinguishable PFGE patterns (pulsotype A) were found in all patient isolates from the outbreak, from several HCWs plus the environmental isolate; all were resistant to ciprofloxacin, clindamycin, erythromycin, gentamicin, tetracycline, and trimethoprim-sulfamethoxazole. Interestingly, the isolate from a patient who had prolonged hospitalization in PICU had PFGE patterns (pulsotype B) distinct from the strains involved in the outbreak. This strain was susceptible to ciprofloxacin and trimethoprim-sulfamethoxazole, and was also found in several HCWs. Thus, there appeared to be 2 main MRSA clones circulating in the PICU of our hospital. CONCLUSIONS: Person-to-person and environment-to-person (or vice versa) transmissions are documented in this study. Strict hand washing before and after patient contact must be enforced and closely monitored, as it is the principal preventive measure in containing the spread of MRSA. To prevent the emergence of vancomycin-resistant MRSA and the further transmission of multidrug-resistant organisms, implementation of periodic and routine active surveillance cultures as part of infection control measures may also be evaluated.     

Clonal Similarities and Sequence-Type Diversity of Invasive and Carriage Streptococcus pneumoniae in India among Children under 5 Years

Background: Pneumococcal pneumonia is one of the major causes of mortality in children less than 5 years in Asia, especially in India. Available PCVs have less serotype coverage in India compared to western countries. Moreover, the baseline pneumococcal serotype and sequence type data is limited and available data doesn’t represent the entire India. With this background we aimed to characterize invasive and carriage isolates of S. pneumoniae from a tertiary care hospital in South India. Materials and Methods: A total of 221 S. pneumoniae isolates, invasive (n=138) and carriage (n=83) between the time period of 2012-2018 were included. Isolates was identified and confirmed using standard laboratory protocols. Serotyping was performed by Customized sequential multiplex PCR and MLST as described in www.pubmlst.org. Results: The major serotypes were 19F, 6B, 14, 6A and 19A and the sequence types (ST) were ST63, 236 and 230. Predominant STs in invasive was ST 63 whereas in carriage were ST4894 and 1701. High level ST diversity in carriage was observed. Majority of the STs were SLVs or DLVs of previously reported STs or PMEN clones. Phylogenetic analyses of the STs revealed gradual expansion of three PMEN CCs CC320, 63 and 230. Conclusion: The vaccine serotypes were the predominant ones found to be associated with IPD, PMEN clones, new STs and antimicrobial resistance. Accordingly, PCV13 is expected to provide invasive serotype coverage of 75% in Indian children less than 5 years. This study provides baseline serotype and sequence type data prior to the introduction of PCV in South India.     

Molecular characterisation of enteroinvasive Escherichia coli O136:K78 isolates from patients of a diarrhoea outbreak in China

Purpose: A diarrhoea outbreak occurred in a kindergarten, which caused 21 relevant infected cases. Our object was to confirm the pathogens and their molecular characterisation. Materials and Methods: Faecal samples from 21 patients were collected on the 3^rd day after their symptom onset, and a regular epidemiological investigation was conducted. Bacterial isolation was performed in accordance with standard laboratory protocol, serological and molecular characterisations were determined by serum agglutination test and real-time polymerase chain reaction (PCR) method, respectively. The pulsed field gel electrophoresis (PFGE) and 16S rRNAs were conducted to determine the homology. Results: Eleven enteroinvasive Escherichia coli (EIEC) O136:K78 strains were isolated. The serum agglutination test showed that all strains’ serotypes were E. coli (EIEC) O136:K78. Real-time PCR showed that 10 (91%) strains carried the invasion plasmid antigen H gene (ipaH), carried by all four Shigella species and EIEC. The strain that didn’t carry the ipaH gene had different biochemical reactions of L-lizyna and L-rhamnose with the other strains. The complete 16S rRNA sequences showed 98.4% identity between ipaH-negative isolate and the others, and the PFGE indicated that the ipaH-negative isolate was not homological with other isolates in this diarrhoea outbreak. Conclusions: The diarrhoea outbreak was caused by E. coli (EIEC) O136:K78.     

Discriminatory Power of Three Typing Techniques in Determining Relatedness of Nosocomial Klebsiella pneumoniae Isolates from a Tertiary Hospital in India

Purpose: The purpose of this study was to evaluate the discriminatory power of two DNA-based technique and a protein-based technique for the typing of nosocomial isolates of Klebsiella pneumoniae. A second objective was to determine the antimicrobial susceptibility pattern and characterise the presence of genes encoding extended-spectrum beta-lactamases (ESBLs) and carbapenemases. Materials and Methods: Forty-six K. pneumoniae isolates from patients with bloodstream infections at a tertiary care hospital in India between December 2014 and December 2015 were studied. All isolates were typed using enterobacterial repetitive intergenic consensus sequence-polymerase chain reaction (ERIC-PCR), randomly amplified polymorphic DNA (RAPD) analysis and matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry. Antimicrobial susceptibility profiles and ESBLs were detected using the BD Phoenix system. The types of ESBL and carbapenemase genes present were detected using PCR. Results: Isolates were subtyped into 31, 30 and 33 distinct genotypes by ERIC-PCR, RAPD and MALDI-TOF, respectively. Several isolates displaying identical DNA fingerprints were binned into different branches based on their proteomic fingerprint. Antimicrobial susceptibility tests revealed that 33/46 strains were multidrug resistant (MDR); a majority of the strains (83%) were sensitive to colistin. PCR-based analysis demonstrated 19 strains to harbour two or more ESBL and carbapenemase genes. Conclusion: ERIC-PCR was the most reproducible method for typing K. pneumoniae isolates and could not be substituted by MALDI-TOF for clonality analysis. A high degree of genetic diversity and the presence of MDR genes highlight the challenges in treating K. pneumoniae-associated infections.     

Matrix-assisted Laser Desorption Ionisation Time-of-flight Mass Spectrometry Rapid Detection of Carbapenamase Activity in Acinetobacter baumannii Isolates

Introduction: Carbapenamase-producing Acinetobacter baumannii are an increasing threat in hospitals and Intensive Care Units. Accurate and rapid detection of carbapenamase producers has a great impact on patient improvement and aids in implementation of infection control measures. Aim: In this study, we describe the use of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI TOF MS) to identify carbapenamase-producing A. baumannii isolates in up to 3 h. Isolates and Methods: A total of 50 A. baumannii isolates (of which 39 were carabapenamase producers) were tested using MALDI TOF MS. Isolates were incubated for 3 h with 0.25 mg/ml up to 2 mg/ml of imipenem (IMP) at 37°C. Supernatants were analysed by MALDI TOF to analyse peaks corresponding to IMP (300 Da) and an IMP metabolite (254 Da) using UltrafleXtreme (Bruker Daltonics, Bremen, Germany). Results: All carbapenamase-producing isolates were evidenced by the disappearance or reduction in intensity of the 300 Da peak of IPM and the appearance of a 254 Da peak of the IPM metabolite. In isolates that did not produce carbapenamase, the IPM 300 Da peak remained intact. Conclusion: MALDI TOF is a promising tool in the field of diagnostic microbiology that has the ability to transfer identification and antimicrobial susceptibility testing time from days to hours.     

New Delhi metallo-β-lactamase and extended spectrum β-lactamases co-producing isolates are high in community-acquired urinary infections in Assam as detected by a novel multiplex polymerase chain reaction assay

Background: The ability of microorganisms to evade antibiotic pressure is challenging in healthcare as patients have little or no drug treatment options. Detection of the prevalence of antibacterial resistance pattern helps towards improved antibiotic policy and empirical treatment. Objectives: We carried out antibiogram profiling and documented the prevalence and co-prevalence of New Delhi metallo-β-lactamase (NDM) and extended spectrum β-lactamases (ESBL) encoding genes in urinary Escherichia coli and Klebsiella pneumonia isolates. Materials and Methods: Antibiotic susceptibilities were tested for 241 isolates of E. coli and K. pneumoniae from urine samples collected from out- and hospitalised patients. Polymerase chain reaction (PCR) was carried out on isolates tested positive for phenotypic production of metallo-β-lactamase and ESBL. A multiplex PCR assay was designed to detect the genes. Results: Multiplex PCR assay designed had a limit of detection of 10³ CFU/mL in vitro. NDM detected was significantly higher among K. pneumoniae compared to E. coli (69.2% vs. 18.2%; P = 0.001). Of 17, 14 NDM positive isolates also harboured ESBL genes. The co-production of CTX-M + TEM + NDM (3/9; 33.3% and 5/8; 62.5%) was most common in K. pneumoniae and E. coli, respectively while CTX-M + TEM + SHV + NDM was found in one isolate. Of the 156 phenotypically ESBL producing isolates, CTX-M, TEM and SHV was detected by PCR in 85, 53 and 24 isolates, respectively. Conclusion: NDM and ESBL co-producing isolates were both community (64.7%) and hospital (35.29%) acquired among E. coli. Antibiotic resistance can be effectively evaluated by a cost and time effective molecular method, such as the multiplex PCR used in this study, which complement culture and sensitivity tests.     

Molecular Confirmation of the Circulating Bacillus anthracis during Outbreak of Anthrax in Different Villages of Simdega District,Jharkhand

Aims and Objectives: Molecular confirmation of the circulating Bacillus anthracis during outbreak of anthrax in different villages of Simdega district, Jharkhand, India. Materials and Methods: Blood samples with swabs from skin lesions (eschar) were collected from the suspected cases of Anthrax from October 2014 to June 2016 from Simdega district, Jharkhand. All the swabs were inoculated on polymyxin lysozyme EDTA thallous acetate media, nutrient agar media as well as 5% sheep blood agar media. Gamma-phage lysis was done. DNA extraction was done using a QIAamp DNA Mini Kit (QIAGEN, Valencia, CA, USA) and subjected to polymerase chain reaction (PCR) using anthrax-specific primers. Results: On Gram and acid fast staining, purple rods and pink-coloured anthrax spores were detected. Capsular and M’Fadyean staining was done. Gamma-phage lysed B. anthracis culture. Of 39 suspected cases, 8 were culture and PCR positive and showed gamma-phage lysis. 3 deaths were reported. Discussion and Conclusion: The conventional and real-time PCR methods are suitable for both the clinical and the epidemiological practice.     

Clostridium difficile infection diagnosis in a paediatric population: comparison of methodologies

The increasing incidence of Clostridium difficile infection (CDI) in paediatric hospitalised populations, combined with the emergence of hypervirulent strains, community-acquired CDI and the need for prompt treatment and infection control, makes the rapid, accurate diagnosis of CDI crucial. We validated commonly used C. difficile diagnostic tests in a paediatric hospital population. From October 2011 to January 2012, 150 consecutive stools were collected from 75 patients at a tertiary paediatric hospital in Perth, Western Australia. Stools were tested using: C. Diff Quik Chek Complete, Illumigene C. difficile, GeneOhm Cdiff, cycloserine cefoxitin fructose agar (CCFA) culture, and cell culture cytotoxin neutralisation assay (CCNA). The reference standard was growth on CCFA or Cdiff Chromagar and PCR on isolates to detect tcdA, tcdB, cdtA, and cdtB. Isolates were PCR ribotyped. The prevalence of CDI was high (43 % of patients). Quik Chek Complete glutamate dehydrogenase (GDH) demonstrated a low negative predictive value (NPV) (93 %). Both CCNA and Quik Chek Complete toxin A/B had poor sensitivity (33 % and 29 % respectively). Molecular methods both had 89 % sensitivity. Algorithms using GDH + Illumigene or GeneOhm reduced the sensitivity to 85 % and 83 % respectively. Ribotype UK014/20 predominated. GDH NPV and GeneOhm and Illumigene sensitivities were reduced compared with adult studies. Quik Chek Complete and CCNA cannot reliably detect toxigenic CDI. A GDH first algorithm showed reduced sensitivity. In a high prevalence paediatric population, molecular methods alone are recommended over the use of GDH algorithm or culture and CCNA, as they demonstrate the best test performance characteristics.     

Online-Only Abstracts

We aimed to provide data on the diagnosis of tuberculous meningitis (TBM) in this largest case series ever reported. The Haydarpasa-1 study involved patients with microbiologically confirmed TBM in Albania, Croatia, Denmark, Egypt, France, Hungary, Iraq, Italy, Macedonia, Romania, Serbia, Slovenia, Syria and Turkey between 2000 and 2012. A positive culture, PCR or Ehrlich-Ziehl-Neelsen staining (EZNs) from the cerebrospinal fluid (CSF) was mandatory for inclusion of meningitis patients. A total of 506 TBM patients were included. The sensitivities of the tests were as follows: interferon-γ release assay (Quantiferon TB gold in tube) 90.2%, automated culture systems (ACS) 81.8%, LÖwenstein Jensen medium (L-J) 72.7%, adenosine deaminase (ADA) 29.9% and EZNs 27.3%. CSF-ACS was superior to CSF L-J culture and CSF-PCR (p <0.05 for both). Accordingly, CSF L-J culture was superior to CSF-PCR (p <0.05). Combination of L-J and ACS was superior to using these tests alone (p <0.05). There were poor and inverse agreements between EZNs and L-J culture (Κ = −0.189); ACS and L-J culture (Κ = −0.172) (p <0.05 for both). Fair and inverse agreement was detected for CSF-ADA and CSF-PCR (Κ = −0.299, p <0.05). Diagnostic accuracy of TBM was increased when both ACS and L-J cultures were used together. Non-culture tests contributed to TBM diagnosis to a degree. However, due to the delays in the diagnosis with any of the cultures, combined use of non-culture tests appears to contribute early diagnosis. Hence, the diagnostic approach to TBM should be individualized according to the technical capacities of medical institutions particularly in those with poor resources.Genome sequencing and characterization of an extensively drug-resistant sequence type 111 serotype O12 hospital outbreak strain of Pseudomonas aeruginosaA. A. Witney¹, K. A. Gould¹, C. F. Pope², F. Bolt², N. G. Stoker¹, M. D. Cubbon³, C. R. Bradley⁴, A. Fraise⁴, A. S. Breathnach², P. D. Butcher¹, T. D. Planche^1,2 and J. Hinds¹1) Division of Clinical Sciences, St George's University of London, 2) Department of Microbiology, St George's Healthcare NHS Trust, London, 3) Brighton and Sussex University Hospitals NHS Trust, Brighton and 4) Hospital Infection Research Laboratory, Queen Elizabeth Hospital, Birmingham, UKOriginal Submission: 7 October 2013; Revised Submission: 20 December 2013; Accepted: 7 January 2014Editor: G. GreubArticle published online: 14 January 2014

Abstract

A series of extensively drug-resistant isolates of Pseudomonas aeruginosa from two outbreaks in UK hospitals were characterized by whole genome sequencing (WGS). Although these isolates were resistant to antibiotics other than colistin, we confirmed that they are still sensitive to disinfectants. The sequencing confirmed that isolates in the larger outbreak were serotype O12, and also revealed that they belonged to sequence type ST111, which is a major epidemic strain of P. aeruginosa throughout Europe. As this is the first reported sequence of an ST111 strain, the genome was examined in depth, focusing particularly on antibiotic resistance and potential virulence genes, and on the reported regions of genome plasticity. High degrees of sequence similarity were discovered between outbreak isolates collected from recently infected patients, isolates from sinks, an isolate from the sewer, and a historical isolate, suggesting that the ST111 strain has been endemic in the hospital for many years. The ability to translate easily from outbreak investigation to detailed genome biology by use of the same data demonstrates the flexibility of WGS application in a clinical setting.Genome-wide re-sequencing of multidrug-resistant Mycobacterium leprae Airaku-3P. Singh¹, A. Benjak¹, S. Carat², M. Kai³, P. Busso¹, C. Avanzi¹, A. Paniz-Mondolfi^4,5, C. Peter⁶, K. Harshman⁶, J. Rougemont², M. Matsuoka³ and S. T. Cole¹1) Global Health Institute, 2) Bioinformatics and Biostatistics Core Facility, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 3) Leprosy Research Centre, National Institute of Infectious Diseases, Tokyo, Japan, 4) Departments of Biochemistry and Dermatopathology, Instituto de Biomedicina, Caracas, Venezuela, 5) Laboratory of Microbiology, Yale School of Medicine/Tuberculosis Reference Laboratory, VA Connecticut Healthcare, New Haven, CT, USA and 6) Centre for Integrative Genomics, University of Lausanne, Lausanne, SwitzerlandOriginal Submission: 29 January 2014; Accepted: 20 February 2014Editor: D. RaoultArticle published online: 25 February 2014

Abstract

Genotyping and molecular characterization of drug resistance mechanisms in Mycobacterium leprae enables disease transmission and drug resistance trends to be monitored. In the present study, we performed genome-wide analysis of Airaku-3, a multidrug-resistant strain with an unknown mechanism of resistance to rifampicin. We identified 12 unique non-synonymous single-nucleotide polymorphisms (SNPs) including two in the transporter-encoding ctpC and ctpI genes. In addition, two SNPs were found that improve the resolution of SNP-based genotyping, particularly for Venezuelan and South East Asian strains of M. leprae.     

Application of PCR fingerprinting using (GACA)4 primer in the rapid discrimination of dermatophytes

Background: Superficial fungal infections have a major impact on cosmetic health, affecting more than 20-25% of the global population, which is predominantly caused by dermatophytes. As per literature search, molecular strain typing of dermatophytes has not been investigated in India. Therefore, the present study was carried out to characterise the dermatophyte species and strains by molecular methods. Objective: To analyse the genotype variability by applying polymerase chain reaction (PCR) fingerprinting using a simple sequence repetitive oligonucleotide (GACA)₄ primer to identify the species and strain variations among the dermatophytes isolated from a tertiary care centre in Chennai. Materials and Methods: From January 2010 to December 2010, 81 dermatophytes were isolated and included for the present study. A simple sequence repetitive oligonucleotide (GACA)₄ was used as a single primer in the amplification process. Results: The (GACA)₄-based PCR successfully amplified all the clinical isolates. Trichophyton rubrum and T. rubrum var. raubitschekii produced identical band profiles, where the latter could not be differentiated from the T. rubrum, which are being reported for the first time from south India. Epidermophyton floccosum produced species-specific band profiles. Intra-species variability was not observed among the T. rubrum and E. floccosum isolates. T. mentagrophytes produced three simple, distinct band patterns, which are surprisingly different from the earlier studies. Conclusion: The PCR-based genotype using the short primer is rapid and precise in direct identification of dermatophyte isolates by one-step PCR to the species level and strain discrimination of the T. mentagrophytes variants.