Unravelling Streptococcus agalactiae: Serotype distribution, virulence factors, obstetrics history and clinical presentation correlations in tertiary care hospitals of the western province of Sri Lanka.

PURPOSE: This study investigated to detect serotypes and virulence genes of Group B Streptococcus (GBS) isolated from pregnant women. METHODS: Forty-five samples of GBS isolates from January to August 2019 at antenatal clinics of 4 teaching hospitals in Western Province, Sri Lanka were included. Isolated GBS were carried to identify 9 serotypes by multiplex PCR. Different virulence determinants, including bac, rib and scp(B) have been detected by PCR. RESULTS: Among GBS-positive culture isolates most abundant serotype detected was type III 12/45 (26.7%) while serotype VII, VIII and IX were not seen. Furthermore, serotype Ia (15.6%); II (20%); V (17.8%); VI (15.6%); Ib (2.2%) and IV (2.2%) were identified. Among 5 rectal isolates, 1 isolate was serotype Ia, 2 isolates were serotype II and 2 isolates were serotype III. Forty (40/45) isolates expressed scpB gene (88.8%). Presence of rib gene was confirmed in 17.8%, bac in 13.3% isolates. ScpB, rib and bac were identified in 4.4% isolates, 8.9% isolates were scpB, rib positive and bac negative, 8.9% isolates were scpB, bac positive and rib negative. These three-virulence genes did not express in 8.9% isolates. ScpB gene was found once in serotype Ib and IV and all serotype VI expressed scpB gene. Rib gene was more common among serotype II and it was not found in serotype Ib, IV and VI. Bac gene was more common in serotype V and it was not found in serotype Ia, Ib and IV. There was not significant association between serotypes and virulence gene (p > 0.05). CONCLUSION: Serotype III is the most abundant serotype. In formulation of vaccine against GBS for Sri Lanka, serotype III should be targeted. Prevalence of vaccine candidate virulence protein such as ß antigens of the C protein (bac) and surface protein Rib (rib) genes were low in this study.

Is adherence to national guidelines for parenteral empiric antibiotic therapy effective? Experience from a Sri Lankan center.

INTRODUCTION: Guidelines for the selection of empirical antibiotics have been developed to improve patient outcomes and reduce unnecessary antibiotic use. We assessed the extent of adherence to the national guidelines for the selection of parenteral empirical antibiotics for three selected infections at a tertiary care center. METHODOLOGY: A prospective cross-sectional study was conducted in medical and surgical wards of a tertiary care hospital in Sri Lanka. Adult patients with a positive culture for a lower respiratory tract infection (LRTI), skin and soft tissue infection (SSTI), or urinary tract infection (UTI) and who were prescribed parenteral empirical antibiotic therapy by the attending physician were included. Bacteria were identified and antibiotic susceptibility was determined by standard microbiological methods. Adherence to the guidelines was defined as prescribing the empiric antibiotic concordant with the national guidelines on the empirical use of antibiotics. RESULTS: A total of 160 bacterial isolates were obtained from 158 patients with positive cultures, the majority were from UTIs (n = 56). The selection of empirical antibiotics was concordant with the national guidelines in 92.4% of patients and 29.5% of the bacterial isolates obtained from these patients were resistant to the prescribed empiric antibiotic. Only 47.5% (76/160) of the bacterial isolates were sensitive to the empiric antibiotic and therefore can be considered an appropriate antibiotic prescription. CONCLUSIONS: Empirical antibiotic guidelines should be updated based on the latest surveillance data and information on prevailing bacterial spectra. Antibiotic prescribing patterns and guideline concordance should be periodically evaluated to ensure whether antimicrobial stewardship programs are moving in the right direction.

Antibiotic Sensitivity of Group B Streptococcus from Pregnant Mothers and Its Association with Resistance Genes.

OBJECTIVE: This study assessed the antibiotic susceptibility and characterized antibiotic resistance genes of group B Streptococcus (GBS) isolates from selected tertiary care hospitals in Western Province, Sri Lanka. METHODS: A descriptive cross-sectional study was carried out to determine antibiotic sensitivity of GBS among 175 pregnant women of >35 weeks of gestation attending antenatal clinics in four teaching hospitals. Low vaginal and rectal swabs were collected separately, and GBS was identified by standard microbiological methods. Antibiotic sensitivity and minimum inhibitory concentration (MIC) were performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. DNA was extracted from culture isolates, and antibiotic-resistant genes were identified by polymerase chain reaction using ermB, ermTR, mefA, and linB genes. RESULTS: GBS colonization in the study sample was 25.7% (45/175) with detection rate of 22.9% (40/175) and 2.9% (5/175) in vaginal and rectal samples, respectively. All isolates were susceptible to penicillin with an MIC range of 0.03-0.12 µg/mL. Six isolates (13.3%) were intermediate, and 11 isolates (24.4%) were resistant to erythromycin. There were 5 intermediately resistant isolates (11.1%) and 10 resistant isolates (22.2%) for clindamycin. Of them, seven had inducible clindamycin resistance (iMLSB). MIC range of erythromycin was 0.03-0.32 µg/mL and that of clindamycin was 0.06-0.32 µg/mL. ermB gene was detected in 7 (15.5%). ermTR gene was found in 16 (35.6%) and was significantly associated with iMLSB phenotype (p = 0.005). mefA gene was detected in two (4.4%) isolates, while linB gene was not detected in tested isolates. CONCLUSION: All isolates were sensitive to penicillin, and the most prevalent resistance genotype was ermTR in the study population.

Biofilm formation and antibiotic resistance among Coagulase Negative Staphylococcus species isolated from central venous catheters of intensive care unit patients.

PURPOSE: This study was conducted to determine the biofilm formation of coagulase negative Staphylococcus species (CoNS) isolated from patients with catheter related blood stream infection (CRBSI) and colonized central venous catheters (CVC) and their antibiotic susceptibility patterns and in situ biofilm formation of CVC tips. METHODS: Eighty-two CoNS isolated from intensive care unit (ICU) patients with CRBSI (n â€‹= â€‹8) or colonized CVC (n â€‹= â€‹74) were included. Species identification and antibiotic susceptibility test were done. All isolates were screened for biofilm formation using crystal violet and 3-(4,5-dimethylthiazole-2-yl)-2-5-diphenyl-2H-tetrazolium bromide (MTT) assays and categorized as strong or moderate biofilm formers. CVC tips were subjected to crystal violet stain and scanning electron microscopy (SEM) to detect in-situ biofilm formation. RESULTS: Staphylococcus haemolyticus (n â€‹= â€‹34; 41%) was the commonest to cause both CRBSI and CVC colonization. All 82 CoNS produced biofilms. Among them 77 (93.90%) were strong biofilm formers including all from CRBSI patients and 05 (6.10%) were moderate biofilm formers as detected by both methods. SEM showed bacteria adhered to surfaces of CVC tips with microbial-aggregates embedded in extracellular matrix. Mean crystal violet absorbance of CVC from CRBSI patients (0.6628) was significantly higher than colonized CVC (mean value 0.5592) (p â€‹= â€‹0.030). S. haemolyticus showed higher resistance to cloxacillin compared to other CoNS (p â€‹= â€‹0.039). CONCLUSION: Majority of CoNS isolated were strong biofilm formers. In-situ biofilm formation on CVC tips were significantly evident in CRBSI patients compared to CVC colonized patients. S. haemolyticus is the commonest to cause both CRBSI and CVC colonization and shows significantly higher cloxacillin resistance rate.

Distribution of mecA and qacA/B genes among coagulase negative staphylococci isolated from central venous catheters of intensive care unit patients.

PURPOSE: This study was designed to detect the prevalence of antibiotic and antiseptic resistance genes, mecA and qacA/B in coagulase negative Staphylococcus (CoNS) species isolated from intensive care unit patients with catheter related blood stream infections (CRBSI) or colonized central venous catheters (CVC). METHODS: Consecutive CoNS isolates from ICU patients with CRBSI or colonized central venous catheters were speciated and antibiotic susceptibilities were determined. The mecA and qacA/B genes were detected by polymerase chain reaction. RESULTS: Eighty-two CoNS isolates from ICU patients with CRBSI (n â€‹= â€‹8) or colonized CVC (n â€‹= â€‹74) were included. The mecA gene was detected in 62 CoNS isolates (76%). The commonest species isolated was S. haemolyticus (n â€‹= â€‹34; 41%) and 30 of these possessed mecA which was significantly higher compared to other CoNS species (p â€‹= â€‹0.036). The qacA/B gene was detected in 13 (16%) isolates. Eleven (13%) CoNS had both genes. A significant association was seen with the presence of mecA and resistance to cloxacillin (p â€‹< â€‹0.001) and erythromycin (p â€‹= â€‹0.046). Presence of qacA/B (p â€‹= â€‹0.007) or both mecA and qacA/B (p â€‹= â€‹0.014) was associated with a higher resistance to clindamycin. CONCLUSION: A considerably high prevalence of mecA and qacA/B genes as well as co-existence of both genes is noted among the CoNS isolated from ICU patients. This indicates the need of taking prompt actions in hospital acquired infection prevention including continuous surveillance.

Appropriateness of the Empirical Antibiotics Prescribed and Their Concordance with National Guidelines for Three Selected Infections among Cancer Patients in a Tertiary Care Centre in Sri Lanka.

BACKGROUND: Prophylactic and empirical antibiotic use is essential in cancer patients due to the underlying immune deficiencies. We examined the spectrum of causative bacteria and the appropriateness of empirical antibiotic prescription for three selected infections in cancer patients. Methodology. A descriptive cross-sectional study was conducted at the National Institute of Cancer (NIC), Sri Lanka, from June 2018 to February 2019. Bacterial isolates obtained from adult cancer patients with a diagnosis of lower respiratory tract infections (LRTI), skin and soft tissue infections (SSTI), or urinary tract infections (UTI) were included. Causative bacteria were identified and the antibiotic susceptibility was determined by standard microbiological methods. Empirical therapy was defined as appropriate if the isolated pathogen was susceptible in vitro to the given antibiotic. RESULTS: A total of 155 bacterial isolates were included in the analysis. LRTI were the most prevalent infections (37.2%, 55/148) encountered during the study period. Majority (90.9%) of the isolated bacteria were ESKAPE pathogens. Klebsiella pneumoniae was the most frequent pathogen causing LRTI (42.4%, 25/59), whereas Escherichia coli (32%, 16/50) and Staphylococcus aureus (26.1%, 12/46) predominated in UTI and SSTI, respectively. Meropenem was the most prescribed empirical antibiotic for LRTI (29.1%, 16/55) and SSTI (26.6%, 11/43) while it was ceftazidime for UTI (36%, 18/50). Only 20.6% (32/155) of the isolated bacteria were susceptible to the empirical antibiotic prescribed while 48.4% (75/155) were resistant to them. The prescribed empirical antibiotic did not have the spectrum of activity for the isolated bacteria in 29% (45/155) of cases. CONCLUSION: High resistance rates were observed against the prescribed empirical antibiotics. National empirical antibiotic guidelines should be revised with updated data on causative organisms and their susceptibility patterns to ensure appropriate empirical antibiotic prescription.

Burden of Respiratory Syncytial Virus Associated Severe Pneumonia in Hospitalized Children.

Respiratory syncytial virus (RSV) is a leading cause of severe respiratory infections. We examined the burden of RSV-associated severe community-acquired pneumonia among hospitalized children and factors that predict RSV etiology. A hospital-based prospective study examined children below five years of age admitted with radiologically confirmed severe or very severe pneumonia in two tertiary care centers in Sri Lanka. Nasopharyngeal secretions (NPS) were tested for 19 viruses by multiplex RT-PCR. Univariate and multivariate analysis was performed to determine whether RSV etiology could be predicted based on clinical, sociodemographic, environmental, radiological, and laboratory parameters. A total of 108 children with severe or very severe were included in the study. At least one virus was found in NPS in 92.5% of children. Forty-six children had RSV (+) pneumonia. Mean RSV proportion was 42.6% (95% CI: 33.1-52.5%, p value = 0.149). RSV as a single virus was found in 41.3% (19/46). The children with RSV (+) pneumonia were younger (p = 0.026) and had lower C-reactive protein (p = 0.003) and household crowding (p = 0.012) than the RSV (-) group, after controlling for confounding covariates. In conclusion, the present study demonstrated that respiratory syncytial virus was the commonest virus associated with CAP in children under five years. Younger age, crowded housing, and lower C-reactive protein levels were predictors of severe RSV-associated pneumonia.

Invasive Candidiasis Associated with Adenovirus Pneumonia.

Invasive Candida infections in immunocompetent children lead to high morbidity and mortality despite available treatment. Candida albicans and Candida parapsilosis are the most common pathogens; however, there are newly emerging pathogenic non-albicans species. Adenovirus accounts for at least 5-10% of respiratory infections in children, and specific serotypes are associated with severe pneumonia. To the best of our knowledge, invasive Candida infection complicating adenovirus-associated pneumonia in immunocompetent children has not been reported previously. Herein, we describe a preschool child with invasive candidiasis associated with adenovirus pneumonia.

In -vitro Biofilm Formation of Vaginal Isolates of Streptococcus agalactiae; Effect of pH and Culture Media

Abstract Background: Streptococcus agalactiae (GBS), a major cause of neonatal morbidity and mortality, is transmitted from mother to neonate via placenta or during birth. Biofilm formation is an important factor in GBS pathogenesis. This study aimed to determine effects of pH, different culture media and nutritional composition on in vitro biofilm forming ability of GBS isolated from pregnant women. Methods: A total of 30 confirmed isolates of GBS from pregnant women were tested for biofilm formation in Todd Hewitt Broth (THB) at pH 4.5,6 and 7. Ten of these isolates were tested for biofilm formation in growth media THB, brain heart infusion broth, tryptic soy broth, Mueller Hinton broth and nutrient broth. Further they were tested for influence of glucose on biofilm formation using crystal violet and MTT assay. Results: Of 30 GBS isolates strong biofilm formation (SBF) was observed at pH 7 in 56.6 %(n=17) while 36.6%(n=11) isolates showed weak biofilm formation (WBF). At pH 4.5, 43.3% (n=13) were non biofilm formers. In THB without glucose, all 10 isolates were SBF while THB with 1% glucose, 3(30%) isolates were SBF, 5(50%) isolates were moderate biofilm producers and 2(20%) isolates were WBF. Ten isolates tested in 5 types of growth media did not show statistically significant difference in biofilm forming ability. Conclusion: All tested vaginal GBS isolates were able to produce biofilms, maximum biofilm formation of GBS was at pH 7.0. and pH 4.5 is not favorable, thus in normal vaginal pH (3.5 - 4.5), GBS finds it difficult to grow biofilms.

A novel low temperature transcutaneous energy transfer system suitable for high power implantable medical devices: performance and validation in sheep.

Transcutaneous energy transfer (TET) systems use magnetic fields to transfer power across the skin without direct electrical connectivity. This offers the prospect of lifetime operation and overcomes risk of infection associated with wires passing through the skin. Previous attempts at this technology have not proved suitable due to poor efficiency, large size, or tissue damage. We have developed a novel approach utilizing frequency control that allows for wide tolerance in the alignment between internal and external coils for coupling variations of 10 to 20 mm, and relatively small size (50 mm diameter, 5 mm thickness). Using a sheep experimental model, the secondary coil was implanted under the skin in six sheep, and the system was operated to deliver a stable power output to a 15 W load continuously over 4 weeks. The maximum surface temperature of the secondary coil increased by a mean value of 3.4 +/- 0.4 degrees C (+/-SEM). The highest absolute mean temperature was 38.3 degrees C. The mean temperature rise 20 mm from the secondary coil was 0.8 +/- 0.1 degrees C. The efficiency of the system exceeded 80% across a wide range of coil orientations. Histological analysis revealed no evidence of tissue necrosis or damage after four weeks of operation. We conclude that this technology is able to offer robust transfer of power to implantable devices without excess heating causing tissue damage.