Variability in adequacy of ventilation during transport of cardiac surgery patients: a cohort study

Inadequate ventilation of intubated patients during transport from the operating theatre to the intensive care unit with attendant hypercarbia may adversely affect haemodynamics. In a retrospective observational study, we assessed the incidence of inadequate ventilation during transport from the operating theatre to the intensive care unit in 99 consecutive cardiac surgery patients admitted to our university tertiary hospital. Demographic, clinical, arterial blood gas and haemodynamic measurements were made on arrival in the intensive care unit after cardiac surgery. The relationships between arterial carbon dioxide tension (P(a)CO2), mean pulmonary artery pressure (MPAP) and other relevant haemodynamic variables were explored. Overall, hypocarbia (P(a)CO2 < 35 mmHg) occurred in 18.2% of patients, while 28.3% of patients had hypercarbia (P(a)CO2 > 45 mmHg). Pulmonary hypertension was common, with nearly half of the cohort having MPAP > or = 25 mmHg and 17.2% > or = 30 mmHg. However there was no association between P(a)CO2 and MPAP (R2 = 0.0076, P = 0.39). Contrary to expectation, neither hypercarbia nor high MPAP were associated with measured adverse outcomes, although this may have been because we studied an insufficient number of patients with extreme values. Associations of higher MPAP, which would be expected to compromise cardiovascular status, included acidaemia, hypoxia and the requirement for noradrenaline. These factors define a group of high-risk patients who should receive particular attention and who should be the focus of future studies.     

Pulsed-field gel electrophoresis of multidrug-resistant and -sensitive strains of Pseudomonas aeruginosa from a Malaysian hospital

Over a period of 6 months from January to June 2002, an unusual increase in the isolation of highly resistant Pseudomonas aeruginosa strains was observed in the various wards and intensive care units of a large general hospital in Johor Bahru, Malaysia. An equal number of multidrug resistant (MDR) and drug-susceptible strains were collected randomly from swabs, respiratory specimens, urine, blood, cerebral spinal fluid, and central venous catheters to determine the clonality and genetic variation of the strains. Macrorestriction analysis by pulsed-field gel electrophoresis showed that the 19 MDR strains were genetically very homogenous; the majority showed the dominant profile S1 (n = 10), the rest very closely related profiles S1a (n = 1), S2 (n = 4), and S2a (n = 3), indicating the endemicity of these strains. In contrast, the 19 drug-sensitive strains isolated during the same time period were genetically more diverse, showing 17 pulsed-field profiles (F = 0.50-1.00), and probably derived from the patients themselves. The presence of the MDR clone poses serious therapeutic problems as it may become endemic in the hospital and give rise to future clonal outbreaks. There is also the potential for wider geographical spread.     

Prevalence and characterization of multidrug-resistant and extended-spectrum beta-lactamase-producing Escherichia coli from pediatric wards of a Malaysian hospital

The emergence of Escherichia coli resistant to extended-spectrum cephalosporins (ESCs) is of concern as ESC is often used to treat infections by Gram-negative bacteria. One-hundred and ten E. coli strains isolated in 2009-2010 from children warded in a Malaysian tertiary hospital were analyzed for their antibiograms, carriage of extended-spectrum beta-lactamase (ESBL) and AmpC genes, possible inclusion of the beta-lactamase genes on an integron platform, and their genetic relatedness. All E. coli strains were sensitive to carbapenems. About 46% of strains were multidrug resistant (MDR; i.e., resistant to ≥3 antibiotic classes) and almost half (45%) were nonsusceptible to ESCs. Among the MDR strains, high resistance rates were observed for ampicillin (98%), tetracycline (75%), and trimethoprim/sulfamethoxazole (73%). Out of 110 strains, bla(TEM-1) (49.1%), bla(CTX-M) (11.8%), and bla(CMY-2) (6.4%) were detected. Twenty-one strains were ESBL producers. CTX-M-15 was the predominant CTX-M variant found and this is the first report of a CTX-M-27-producing E. coli strain from Malaysia. Majority (3.1%) of the strains harbored class 1 integron-encoded integrases with a predominance of aadA and dfr genes within the integron variable region. No gene cassette encoding ESBL genes was found and integrons were not significantly associated with ESBL or non-ESBL producers. Possible clonal expansion was observed for few CTX-M-15-positive strains but the O25-ST131 E. coli clone known to harbor CTX-M-15 was not detected while CMY-2-positive strains were genetically diverse.     

Comparison of BACTEC MGIT 960 system and BACTEC 460 TB system for growth and detection of Mycobacteria from clinical specimens

This study was carried out to compare the performance of BACTEC MGIT 960 with the BACTEC 460 TB for growth and detection of Mycobacteria from human clinical specimens. The BACTEC MGIT 960 instrument is a fully automated system that utilizes MGIT tubes containing an oxygen sensor embedded in silicon at the bottom and filled with 7 mL of modified Middlebrook 7H9 broth. Identical samples were inoculated into the two automated systems and incubated for six weeks. Over a period of three months, 279 specimens were decontaminated and processed according to the standard CDC NALC/NaOH method, using the commercial MycoPrep kit. Forty-two specimens (15%) yielded Mycobacterium tuberculosis; 37 (88%) were detected by the fluorescent BACTEC MGIT 960 and 35 (83%) detected by the radiometric BACTEC 460 TB. Fifteen specimens (5%) yielded Mycobacterium Other Than Tuberculosis (MOTT); 10 (66%) were detected by BACTEC MGIT 960 and 11 (73%) detected by BACTEC 460 TB. The average time to detection and contamination rates and the average time to obtain results of antimicrobial susceptibility tests between the two systems were compared. The performance of the BACTEC MGIT 960 was comparable to the BACTEC 460 TB system which has been the "Gold Standard" for automated detection of TB. The former was more rapid, as sensitive and less labour intensive than the BACTEC 460. Our data demonstrates that the BACTEC MGIT 960 system is an accurate, automated and a non-radioactive alternative to the BACTEC 460 TB for the culture and susceptibility testing of M. tuberculosis.     

Rotavirus and other enteropathogens in childhood acute diarrhoea: a study of two centres in Malaysia

AIM: To study the role of rotavirus in children hospitalised for acute gastroenteritis (AGE) in two urban hospitals in Malaysia. METHODS: A 12-month prospective study (January to December 2002), in children younger than 14 years with AGE hospitalised to the paediatric units of University of Malaya Medical Centre (UMMC), Kuala Lumpur; and Hospital Sultanah Aminah (HSA), Johor Bahru, Malaysia was conducted. RESULTS: In 2002, 399 and 1307 children with AGE were admitted to UMMC and HSA, respectively. Two hundred and eighty-eight (72%) stool samples from UMMC and 901 (69%) samples from HSA were analysed. Rotavirus was the most common aetiological agent identified in both centres (average 32%; UMMC 35%, HSA 30%, P = 0.94). The peak age group for rotavirus-related hospitalisation was 24-35 months for UMMC and 12-23 months for HSA. Nine percent of patients hospitalised for rotavirus infection in UMMC and 22% of patients in HSA were older than 5 years of age. An outbreak of rotavirus infection within the communities served by both centres resulting in an increase in hospital admissions of rotavirus gastroenteritis was observed in both units from January to March 2002. CONCLUSION: The peak age group for rotavirus-related hospital admission in this study was much older, between 12 to 35 months. It is uncertain whether this was related to the outbreak of rotavirus gastroenteritis observed within two urban areas from January to March 2002 causing re-infection with rotavirus in older children.     

Chikungunya virus of Asian and Central/East African genotypes in Malaysia

BackgroundChikungunya virus (CHIKV) of the Central/East African genotype has caused large outbreaks worldwide in recent years. In Malaysia, limited CHIKV outbreaks of the endemic Asian and imported Central/East African genotypes were reported in 1998 and 2006. Since April 2008, an unprecedented nationwide outbreak has affected Malaysia.ObjectiveTo study the molecular epidemiology of the current Malaysian CHIKV outbreak, and to evaluate cross-neutralisation activity of serum from infected patients against isolates of Asian and Central/East African genotypes.Study designSerum samples were collected from 83 patients presenting in 2008, and tested with PCR for the E1 gene, virus isolation, and for IgM. Phylogenetic analysis was performed on partial E1 gene sequences of 837 bp length. Convalescent serum from the current outbreak and Bagan Panchor outbreak (Asian genotype, 2006) were tested for cross-neutralising activity against representative strains from each outbreak.ResultsCHIKV was confirmed in 34 patients (41.0%). The current outbreak strain has the A226V mutation in the E1 structural protein, and grouped with Central/East African isolates from recent global outbreaks. Serum cross-neutralisation activity against both Central/East African and Asian genotypes was observed at titres from 40 to 1280.ConclusionsThe CHIKV strain causing the largest Malaysian outbreak is of the Central/East African genotype. The presence of the A226V mutation, which enhances transmissibility of CHIKV by Aedes albopictus, may explain the extensive spread especially in rural areas. Serum cross-neutralisation of different genotypes may aid potential vaccines and limit the effect of future outbreaks.     

Risk factors and clinical outcome of profound thrombocytopenia in adult patients with DENV infections

Severe thrombocytopenia is common in dengue virus (DENV) infections. However, studies focusing on the role of profound thrombocytopenia (PT) (nadir platelet counts ≤ 20 000/mm³) in DENV infections are scarce. This study aims to identify the associated features and outcome of DENV patients with PT. It involves 237 adult hospitalized patients who were DENV PCR positive. The presence of comorbidity (AOR = 4.625; 95% CI = 1.113–19.230), higher admission hematocrit (AOR = 1.213; 95% CI = 1.067–1.379), lower admission albumin (AOR = 0.870; 95% CI = 0.766–0.988) and lower admission platelets (AOR = 0.980; 95% CI = 0.969–0.991) was associated with platelets ≤ 20 000/mm³ in multivariate logistic regression. PT was not affected by DENV serotypes, coinfections and secondary DENV infections. Patients with PT had significantly higher risk of experiencing warning signs (AOR = 3.709, 95% CI = 1.089–12.634) and longer hospital stay (AOR = 1.943, 95% CI = 1.010–3.774). However, severe dengue disease, hemorrhagic manifestations and need for intensive care were not significantly associated with PT.