Optimal detection of carbapenemase-producing Enterobacteriaceae from rectal samples: a role for enrichment?

BACKGROUND: Successful laboratory detection of carbapenemase-producing Enterobacteriaceae (CPE) in patient surveillance samples is a diagnostic challenge. In the absence of a reference standard for screening rectal swabs for CPE, many phenotypic, genotypic, culture- and non-culture-based assays have been proposed for identifying these bacteria. AIM: To develop and optimize a CPE screening protocol capable of identifying all frequently encountered CPE, including those producing OXA-48-like carbapenemases. METHODS: Faropenem susceptibility testing was performed on 507 presumptive CPE isolated from diagnostic samples and CPE rectal screens between March and August 2016. Results from this CPE screening method were compared to those from direct culture on mSuperCARBA™, temocillin enrichment culture, and use of an antibiotic resistance algorithm, to determine the optimal method to employ in the detection of CPE. FINDINGS: Faropenem was a poor predictor of carbapenemase production (58% true positives). The combination of a temocillin enrichment stage and interpretive reading of antibiotic resistance phenotypes improved the recovery and identification of CPE significantly (91% true positives), especially for OXA-48 producers (P = 0.03). CONCLUSION: The combination of temocillin enrichment, a selective chromogenic medium, and an antibiotic resistance-based algorithm significantly improved the detection of all CPE recovered from routine and targeted surveillance samples.

Cardiovascular response in anemia.

OBJECTIVE: To study the functional consequences of nutritional anemia by evaluating the exercise performance in these children. METHODS: The study was conducted on 30 each of anemic and normal children of both sexes aged between 7 and 14 years. Relevant history was taken, and detailed examination was done. These children were classified according to severity of anemia based on hemoglobin estimation as mild (10-11.9 g/dl), moderate (7-9.9 g/dl) and normal (>12 g/dl). Children with severe anemia (Hb < 7g/dl), heart disease, non-nutritional anemia, acute febrile or respiratory illness were excluded. The subjects were tested on Mortara X Scribe colour stress treadmill using the modified Bruce protocol. Continuous computerised electrocardiographic analysis was done. The parameters studied included heart rate, systolic blood pressure, double product (DP = HRxSBP), ECG changes, metabolic equivalents (METS) and exercise duration. The end point of the test was a HR of 170/min (non-fatigue group) or inability to perform further (fatigue group). Statistical analysis was done by appropriate tests. RESULTS: Fifteen children each with mild and moderate anemia and 30 age-matched controls were enrolled in the study. There was no significant difference in the resting HR, exercise duration or DP between the cases and controls. Thirty-one children reached the target HR (non-fatigue group). The end-point HR was significantly lesser among the anemic children in the fatigue group (P 0.04). The percent gain of SBP, at peak exercise (P 0.0007) and recovery SBP as percent of resting SBP (p 0.006) were significantly more in the anemic children, more so in the mildly anemic ones. Lesser METS was achieved by anemics as compared to controls (P 0.04). ECG changes occurred significantly more often in anemic children, 53.8% of those with changes being moderately anemic, the main abnormality being ST depression. None developed arrhythmia during exercise testing. CONCLUSION: The cardiovascular response to physical exercise is compromised in children with nutritional anemia and hence these children may never attain their full potential in various school activities. Prevention of anemia should be a priority in school going children.

Extended-spectrum beta-lactamase producing enterobacteriaceae in a tertiary care hospital in Trinidad and Tobago.

Extended-spectrum beta-lactamase (ESBL) mediated resistance to third generation cephalosporins, amongst the family Enterobacteriaceae, is emerging worldwide. This is the Caribbean's first survey on ESBL production, and was conducted during two six-month periods in 1998 and 2001, in a tertiary health institution in Trinidad and Tobago. Consecutive ampicillin resistant isolates of the family Enterobacteriaceae from in-patients were screened for resistance to third generation cephalosporins, and for ESBL production. The proportion of isolates found to be ESBL producers was similar in both samples (40 of 560 and 23 of 361). Overall, ESBL production was more frequent in enterobacter, citrobacter and proteus (and related organisms) than in Klebsiella and Escherichia (11.2% and 4.6%, respectively, p < 0.001). In the 1998 sample, this proportion (9.8% versus 5.8%) was significant (p < 0.05), but the difference was more marked in the 2001 sample (13.6% versus 2.9%, p < 0.001). Continued distribution of these resistant bacterial strains is of concern. In the Caribbean region, more laboratory surveillance and increased infection control vigilance are recommended, with focus on specific genera in the family.

Extended-spectrum beta-lactamase producing enterobacteriaceae in a tertiary care hospital in Trinidad and Tobago

Extended-spectrum beta-lactamase (ESBL) mediated resistance to third generation cephalosporins, amongst the family Enterobacteriaceae, is emerging worldwide. This is the Caribbean's first survey on ESBL production, and was conducted during two six-month periods in 1998 and 2001, in a tertiary health institution in Trinidad and Tobago. Consecutive ampicillin resistant isolates of the family Enterobacteriaceae from in-patients were screened for resistance to third generation cephalosporins, and for ESBL production. The proportion of isolates found to be ESBL producers was similar in both samples (40 of 560 and 23 of 361). Overall, ESBL production was more frequent in enterobacter, citrobacter and proteus (and related organisms) than in Klebsiella and Escherichia (11.2 and 4.6, respectively, p < 0.001). In the 1998 sample, this proportion (9.8 versus 5.8) was significant (p < 0.05), but the difference was more marked in the 2001 sample (13.6 versus 2.9, p < 0.001). Continued distribution of these resistant bacterial strains is of concern. In the Caribbean region, more laboratory surveillance and increased infection control vigilance are recommended, with focus on specific genera in the family

Sensorineural hearing loss following acute bacterial meningitis in non-neonates.

OBJECTIVE: Sensorineural hearing loss (SNHL) is an important sequelae of acute bacterial meningitis (ABM) in children. This study was undertaken to determine the incidence of SNHL following meningitis in non-neonates and its correlation with various factors. METHODS: Children between the ages of 1 month and 12 years with ABM admitted in a teaching hospital over a period of 18 months were enrolled. Detailed history was taken, clinical examination performed and cerebrospinal fluid analyzed at commencement of therapy, 48 hours later and at the end of treatment. On discharge brainstem evoked response audiometry (BERA) was recorded. Data were analyzed using appropriate statistical tests. RESULTS: Out of 32 children enrolled, 9 (28.1%) developed SNHL, bilateral in 21.9% and unilateral in 6.2%. Among hearing impaired subjects, 11.2% had mild while 44.4% each had moderate and profound hearing loss. Age, presence of vomiting, altered sensorium seizures and aminoglycoside usage were not significantly different in those with and without SNHL, but the total duration of fever was (p<0.05). There was significantly higher protein content and neutrophils in the second CSF sample of those with SNHL. CONCLUSION: There is a greater than 50% probability of the child developing SNHL if neutrophil percentage in the second CSF is 80% or more. Since the overall risk of SNHL is significant in children with meningitis, it is recommended that BERA be recorded in all, so that early intervention may be possible.

A regulatory role of sulfhydryl groups in modulation of sperm membrane conformation by heavy metals: sulfhydryl groups as markers for infertility assessment.

Sperm membrane sulfhydryl groups, when masked by heavy metals like cobalt and copper at very low concentration (10(-9)) shows inhibition of lipid peroxidation and superoxide dismutase activity. Inhibition of lipid peroxidation is suggested to lead to reduction in membrane fluidity, a prerequisite for normal sperm function. Augmentation of lipid peroxidation by pentoxifylline in oligospermia provides evidence to this hypothesis that membrane sulfhydryls play a regulatory role in membrane modulation. It is therefore suggested that these sulfhydryl groups can be used as a tool for infertility assessment in unexplained male infertility.

Determination of high level resistance to aminoglycosides among enterococci.

Two hundred and ten strains of enterococci showing resistance to gentamicin (10 micrograms/disc) were tested for high level resistance by detecting the minimum inhibitory concentration and by using high content disc diffusion test. Only 67 per cent of these had high level resistance to gentamicin. High level kanamycin resistance in the group was 84 per cent, while high level streptomycin resistance was 61 per cent. Only 85 of the 140 strains with high level gentamicin resistance had similar streptomycin resistance. Results using locally made high content discs, correlated 100 per cent with MIC results. High level resistance to enterococci should be reported on a routine basis, especially when isolated from patients with serious infections.