Time for a culture change? Suboptimal compliance with blood culture standards at a district hospital in Cape Town.

BACKGROUND: The benchmark for contaminated blood cultures (BCs) is 3%. The South African (SA) guideline aims to optimise BC yield and reduce contamination. Data on BC collection practices in SA since the publication of the 2010 SA guideline are lacking. OBJECTIVE: To evaluate compliance with the national guideline for the optimal use of BCs and determine the BC contamination rate at a local district hospital. METHOD: An audit of compliance with 22 BC standards was conducted at a district hospital in Cape Town, SA. Standards were evaluated by reviewing clinical and laboratory data and by a clinician questionnaire. RESULTS: Of the 425 BCs reviewed, 12.5% had positive growth, and 4.5% grew contaminants. Only 33% of BC bottles contained the recommended fill volume of 8-10 mL, and 96.9% of patients had a single BC within a 24-hour period. Of all the BCs, only 7.8% had a combined blood volume of at least 20 mL. The yield of pathogens in BCs collected after antibiotic exposure was 4.9% compared with 7.5% for those cultures with no prior antibiotic exposure (p=0.3). The overall median needle-to-incubator transport time was 11 hours 25 minutes. CONCLUSION: The BC contamination rate was high and compliance with most standards was variable or not met. The findings may not be generalisable to other hospitals, and we recommend that each institution reviews its own BC practices. Recommendations made to hospital staff included a re-audit following implementation of these recommendations.

Characterisation of Staphylococcus Aureus Bacteraemia at Tygerberg Hospital

To elucidate the local epidemiology of Staphylococcus aureus bacteraemia; we characterised blood culture isolates using molecular methods and prospectively collected clinical data to determine the occurrence of community-acquired; methicillin-resistant S. aureus (MRSA). Consecutive S. aureus blood culture isolates were collected over a one-year period from patients who were admitted to Tygerberg Academic Hospital in the Western Cape. A multiplex polymerase chain reaction (PCR) was used for the detection of spa; mecA and lukS/F-PV genes. Strain typing was performed using spa typing. Multiplex PCR for staphylococcal cassette chromosome mec (SCCmec) typing was also performed; as well as multilocus sequence typing (MLST) on selected isolates. Cases were categorised by clinical data as either hospital-acquired; healthcare-associated or community-acquired. One hundred and thirteen S. aureus isolates (30 MRSA) were collected from 104 cases of bacteraemia. According to clinical data; all community-acquired infections; 54 of hospital-acquired cases and the majority of healthcare-associated cases were due to methicillin-sensitive S. aureus (MSSA). Furthermore; all Panton-Valentine leukocidin (PVL)-positive isolates (15.9 of all S. aureus) were MSSA. MRSA strains were isolated from hospital-acquired cases (with a minority of healthcare-associated cases) and clustered mainly in spa-CC701 and CC012. SCCmec type IV was predominant. MLST clones included ST239-MRSAIII; ST36-MRSA-II and ST612-MRSA-IV. The predominant source for S. aureus bacteraemia was catheter-related infection (39). Community-acquired S. aureus infections in our setting remain sensitive to methicillin and current treatment guidelines suffice. The majority of hospital-acquired and healthcare-associated infections were catheter-related. Prevention and treatment should be targeted accordingly

The changing profile of pediatric meningitis at a referral centre in Cape Town, South Africa.

BACKGROUND: Pediatric meningitis remains a common cause of childhood morbidity and mortality in developing countries. Knowledge of the causative organisms in a region is of importance in guiding empiric antibiotic regimes and immunization schedules assisting decisions on primary health-care interventions. METHODS: This retrospective review of 557 meningitis cases represents a third pediatric survey conducted over a 3-year period (January 2007 to December 2009) at the same institution and after an interval of 14 years. Cases were identified using cerebrospinal fluid results. Demographic and laboratory variables were collected and meningitis was classified as aseptic/viral, bacterial, septic, tuberculous meningitis (TBM) or fungal. RESULTS: The commonest form of bacterial meningitis was TBM diagnosed in 22% (n = 126) of children. Streptococcus pneumoniae 4% (n = 23) and Klebsiella pneumoniae 3% (n = 17) were the next commonest causes of bacterial meningitis diagnosed. Haemophilus influenzae meningitis occurred in <1% (n = 3) of cases with a median age of 3 months. Aseptic meningitis remains the commonest category. Human immunodeficiency virus (HIV) testing was requested in 43% (n = 241) of cases; 8% (n = 46) were positive. CONCLUSION: TBM remains the commonest cause of pediatric bacterial meningitis in the Western Cape. It is concerning that the percentage of TBM cases out of the total study population has more than doubled compared with that in previous surveys. The low prevalence and young age of H. influenzae meningitis cases confirm the benefits derived from H. influenzae type b (Hib) vaccination.

Superior Detection of Pathogens in Synovial Fluid by the Bactec 9240 Peds Plus/F System Compared to the Conventional Agar-Based Culture Method

Abstract:To improve culture yield in cases of possible septic arthritis; we compared culture of joint fluid aspirates on conventional agar-based media to culture in Bactec 9240 Peds/Plus F blood culture bottles with and without the addition of fastidious organism supplement (FOS). Over a period of 21 months; we analysed 123 synovial fluid samples and isolated 20 pathogens. The Bactec methods proved superior by yielding more pathogens than the conventional culture method (p=0.074). However; this method also yielded more contaminants within the first three days of incubation (p=0.027). All contaminants detected after three days of incubation were the result of overgrowth on conventional method agar plates. The Bactec methods provided clinicians with a positive pathogen result one day earlier than the conventional counterpart (p=0.001). Four isolates of Neisseria gonorrhoeae were only cultured with the Bactec method. No significant benefit was demonstrated by supplementing blood culture bottles with FOS. We recommend that whenever infection by fastidious organisms is suspected; synovial fluid aspirates should be cultured using automated blood culture systems to increase the culture yield and to decrease the time to detection