Harsha Samarasekara

Analysis of quality improvement forms in anatomical pathology in Sri Lankan tertiary care reference laboratory

S S81 medical literature lines up accordingly with these produced scores. Discussion: The study displays the developing a numeric framework for developing ‘critical values’ in anatomic pathology is possible, and that this correlates well with contemporary consensus. References 1. Renshaw S, Gould EW, Renshaw AA. Unexpected expectations in critical values in anatomic pathology. Arch Pathol Lab Med 2011;

Analysis of positive bacteriology cultures at a regional microbiology in view of understanding local epidemiology and improving the quality of services

Aim Analysis of positive bacteriology specimens performed over one year to determine local epidemiology data and to improve methods and reporting procedure. Methods The study was performed at a regional microbiology laboratory servicing a large number of rural health facilities. All positive bacteriology cultures for 7467 organisms were extracted from the laboratory information system and analysed using Microsoft Excel. This included 354 positive blood cultures, 1696 wound swabs, 2293 urine cultures and 512 sputum samples. Susceptibility data were analysed for Staphylococcus aureus, Enterococci, ESCPPM and non-ESCPPM groups of Enterobacter-iaceae and Pseudmonas aeruginosa. Observations were made regarding current methodology and opportunities for improvements with ongoing support of supervising laboratory were identified. Results Direct susceptibility data for urine specimens for ampi-cillin, amoxycillin-clavulanate, cephalothin, gentamicin and tri-methoprim for non-ESCPPM organisms were 43%, 76%, 45%, 98% and 80%, respectively; the ESCPPM group of organisms showed susceptibilities of 93% for gentamicin and 78% for trimethoprim and 88% for norfloxacin. The single anti-Pseudomonal drug tested, gentamicin, showed 99% susceptibility. Eighty percent of Enterococci remained susceptible to ampicillin. Forty percent of urinary S. aureus were methicillin-resistant Staphylococcus aureus (MRSA) with the majority community (CMRSA). Susceptibilities for bacteraemic S. aureus isolates included 88% of methicillin-sensitive Staphylococcus aureus (MSSA), 10% of CMRSA and 2% of nosocomial MRSA. Non-ESCPPM organisms showed susceptibilities of 48%, 67%, 92%, 92% 98% and 100% for ampicillin, amoxycillin-clavulanate, gentamicin, cefotaxime, ciprofloxacin and meropenem, respectively. Susceptibilities of bacteraemic ESCAPPM isolates for gentamicin, ciprofloxacin and meropenem were 100%, 88% and 100%. Sixty-two percent of Enterococci remained susceptible to ampicillin. Conclusions A number of analytical and post-analytical factors were identified with potential improvements to be done in view of upgrading the quality of services.

Phenotypic and molecular characterisation of metallo-beta lactamases (MBLs) producing bacteria at a tertiary care hospital

Introduction In 2005–2006 at the department of Microbiology, Nepean Hospital, multiresistant Gram negative rods were increasingly encountered at the sensitivity bench. They carried phenotypic markers of resistance to cefotaxime and ceftazidime and gentamicin and were not extended spectrum beta lactamases (ESBLs). Isolates originated mainly from the neonatal intensive care unit (NICU) and were identified as carrying IMP-4 gene. These organisms present a challenge to the routine microbiology laboratory because of variable phenotypic expression, the range of organisms involved and the need for rapid results. As this genetic element was new, a greater understanding of the problem in the local environment was required and this prompted us to look at improved screening for these organisms using a mixture of phenotypic and molecular methods. Aims (1) To establish rapid and low cost PCR to detect IMP-4 gene and low cost phenotypic test/s to screen for metallo-beta lactamases (MBLs). (2) To evaluate the performances of phenotypic tests. Methods A total of 276 Gram negative clinical isolates recovered from the sensitivity bench were studied. The 276 isolates comprised of 100 isolates sensitive to third generation cephalosporins and aminoglycosides, 83 stored historical isolates resistant to either/both drugs and 93 isolates from the surface swabs and urine of NICU babies where it was thought an ongoing outbreak of MBL positive bacteria was occurring. The bacterial isolates were identified and tested using VITEK and CLSI disk diffusion. Phenotypic testing for MBL detection was performed using EDTA and 2-Mercaptopropionic acid (2-MPA) as described in the literature. Real time PCR was performed for IMP-4 gene. For the isolates with discrepant phenotypic and molecular tests, a multiplex PCR was performed to detect the majority of described MBLs. Results IMP-4 gene was detected in 20.2% of the study population. EDTA has sensitivity of 95% and specificity of 89% and 2-MPA has sensitivity of 95% and specificity of 70% for MBL detection. Sixty- seven false positives were detected in 2-MPA test and 26 in EDTA test. No MBLs other than IMP-4 were detected by multiplex PCR. Conclusions Phenotypic tests are useful as they are cheap, quick and easy to perform in a routine microbiology laboratory. They are highly sensitive but the higher number of false positives among non-fermenters is a cause for concern. MBL gene detection by real time PCR is highly sensitive and specific, results can be obtained within a few hours, and they are therefore extremely useful in outbreak situations to initiate infection control measures. However, geographically prevalent MBL genes should be targeted in a multiplex PCR.