Welcome to the WSPID 2022 Virtual Congress Calendar

Background

Real time PCR (RT-PCR) is an alternative approach for the identification and quantification of pneumococci directly from samples.

Aims

To compare pneumococcal detection rates using culture and RT-PCR and to compare pneumococcal colonization density in healthy children and hospitalized children with respiratory symptoms.

Methods

284 nasopharyngeal swabs (NPSs) obtained from children between 2 months to 2 years of age were included; 101 were from healthy children while 183 were from children with respiratory symptoms. An RT-PCR assay targeting lytA was done alongside with culture based methods.

A standard curve was plotted using DNA from ATCC 49619 strain of Streptococcus pneumoniae with a 10-fold dilution series. RT-PCR positivity as defined by a Cq value of =< 35

Results

The overall colonization rate detected by conventional culture was 41.2% (n=117) while RT-PCR detection rate was 43.7% (n=124). The colonization rate detected by RT-PCR in the healthy cohort was 33.7% (n=34) and it was 49.2% (n=90) in the hospitalized cohort. It was 37.6% (n=38) and 43.2% (n=79) for the two cohorts by culture. The mean Cq value for the healthy cohort was 29.61±2.85 and 28.93±3.62 for the hospitalized cohort.

The mean genomic DNA copy numbers detected in children with respiratory symptoms was log10 7.49 (SD 1.07) while it was log10 7.30 (SD 0.23) in healthy children.

Conclusions

There was a higher detection of pneumococcal colonization using RT-PCR.

A higher pneumococcal colonization density was detected in hospitalized children with respiratory symptoms.

Acknowledgements

Research grant WI216479 through Pfizer for financial assistance.

Background

Carbapenem resistance in gram negative bacteria(GNB) is major concern in the management of resistant infections. The mechanism of carbapenem resistance is primarily mediated by carbapenemases. Five most common genes (NDM , KPC , VIM , OXA , IMP) are responsible for carbapenemase production. Knowledge of these genes is important as management will vary according to the type of resistant gene.

Aims

To estimate the prevalence of different genes responsible for carbapenemase production in GNB at a tertiary health care center in South India.

Methods

In this retrospective study, samples were collected over 16 months. GNB which grew on culture, showed resistance to carbapenem (meropenem mic>8) were tested by Xpert Carba-R Assay for the detection of five important genes responsible for carbapenemase production ; NDM, KPC, VIM, OXA, and IMP.

Results

Total 184 cultures were collected which suggested carbapenem resistance GNB . 12 samples were excluded as they were repeat samples. Rest 172 samples grew Klebsiella pneumonae(152), Escherichia coli(10), acinetobacter species(6), Pseudomonas(2) and Enterobacter(2). Among them , OXA 48 and NDM are most common gene with 137 (83.5%) and 97(59.1%) respectively. 70 samples(42.6%) showed presence of both , 1 (0.6%) showed presence of OXA 48, NDM, and VIM. IMP and KPC gene were not detected.

Conclusions

In view of limited options and higher cost of antibiotics, knowledge of genes responsible for carbapenem resistance is a cost effective approach. This will helps to select appropriate antibiotics, rational use of antibiotic therapy and reduce the mortality and morbidity.

Background

Misdiagnosis of Malaria could result in significant morbidity and mortality. Rapid, accurate and accessible detection of falciparum and non-falciparum malaria parasites through the use of local combined HRP2/pLDH (Pan) Rapid Detection Test (RDT) with a paired blood film has an important role in addressing this. However, there are known limitations to the efficacy of RDTs such us its lack of validation for the recognition of Knowlesi malaria, currently prevalent in some countries of Southeast Asia.

Aims

To establish the local diagnostic accuracy of the use of a single paired RDT and blood film to rule out Malaria disease in well children.

Methods

Methods

Retrospective study of 198 presumed cases of imported Malaria seen at SCH between 2014 and 2019. All of them had at least one RDT, blood film and Full blood count to exclude disease. Hospital numbers were facilitated by our local Haematology lab. The data was collected from local electronic records. Data analysed using Microsoft Excel and MedCalc software.

Results

Results

Overall, a single RDT was diagnostically accurate in all 17 cases of confirmed Malaria (100.00%; 95% CI 98.15%-100.00%) of which 15 had a positive paired blood film (98.99%; 95% CI 96.40%-99.88%). All confirmed cases seen at SCH travelled from African countries and presented with symptoms and abnormal FBC.

Conclusions

Conclusion

The use of a single paired RDT and blood film could be enough to rule out Malaria disease in well children, with normal FBC results, who travel from low-risk areas for Knowlesi malaria.

Background

One explanation to why children are infected less frequently and severely than adults is that cross-reactive human common cold coronavirus (HCoV) immunity, could confer some protection. In addition, it has been reported that children have lower levels of spike protein antibodies than adults, and their accumulative humoral response is more expanded to “accessory proteins” like nsp1. Nsp1 plays a critical role in coronaviruses replication and virulence.

Aims

The aims were to predict B and T cell epitopes that could be recognized in human and to assess the epitope conservancy across different coronavirus species.

Methods

Nsp1 protein sequences of SARS CoV-2, HCoV.229E, HCoV NL63, HCoV OC43 and HCoV HKU1 were obtained from GenBank. MAFFT tool was used for multiple sequence alignment. BepiPred-2.0 and NetMHCpan EL 4.1 prediction methods were used to identify sequential B cells and MHC-I restricted T cell epitopes, respectively, and epitope conservancy was determined.

Results

B epitopes GQEWH67-71, and LHSLGGF109-115 in nsp1 of HCoV HKU1; EAASNGFR33-40 and KFSDRPF77-83 in nsp1 of HCoV 229E, and PLGMSLEAC108-116, and PVQSR135-143 in nsp1 of HCoV OC43 showed levels of epitope conservancy in nsp1 of SARS CoV-2 higher than 30%. PVQSR and its counterpart in nsp1 of SARS CoV-2 (GEIPVAY112-118) contain or are flanked by amino acids conserved in alpha and beta-coronavirus. MHC class I restricted T cell epitopes with levels of conservancy higher than 30% were found. Their counterparts in SARS CoV-2 protein also showed high prediction scores for some HLA molecules.

Conclusions

Cross-reactive immunity could explain aspects of differential clinical outcome in children and adults

Background

Selection for antibiotic resistance remains a concern with long-term azithromycin (AZM) use in chronic lung diseases (CLD).

Aims

We investigated the impact of 48 weeks of AZM on the carriage and antibiotic resistance of common respiratory bacteria among children with HIV-associated CLD.

Methods

Nasopharyngeal (NP) swabs and sputa were collected at baseline, 48 and 72 weeks from participants with HIV-associated CLD randomised to receive weekly AZM or placebo for 48 weeks and followed post-intervention until 72 weeks. The primary outcomes were prevalence and antibiotic resistance of Streptococcus pneumoniae (SP), Staphylococcus aureus (SA), Haemophilus influenzae (HI), and Moraxella catarrhalis (MC) at these timepoints. Mixed-effects logistic regression and Fisher's exact test were used to compare carriage and resistance respectively.

Results

Of 347 (174 AZM, 173 placebo) participants (median age 15 years [IQR =13–18], females 49%),NP carriage was significantly lower in the AZM (n=159) compared to placebo (n=153) arm for SP (18% vs 41%, p<0.001), HI (7% vs 16%, p=0.01), and MC (4% vs 11%, p=0.02); SP resistance to AZM (62% [18/29] vs 13%[8/63], p<0.0001) or tetracycline (60%[18/29] vs 21%[13/63], p<0.0001) were higher in the AZM arm. Carriage of SA resistant to AZM (91% [31/34] vs 3% [1/31], p<0.0001), tetracycline (35% [12/34] vs 13% [4/31], p= 0.05) and clindamycin (79% [27/34] vs 3% [1/31], p<0.0001) was also significantly higher in the AZM arm and persisted at 72 weeks. Similar findings were observed for sputa.

Conclusions

The risk of drug resistance should be considered during long-term AZM use. The clinical significance of antibiotic resistance needs investigation.

Background

Urinary tract infections (UTIs) are among the most common bacterial infections in children and E.coli is the main responsible pathogen. Given the current increasing rates of antibiotic resistance worldwide, the choice of empiric therapy (ET) often results inappropriate.

Aims

To compare clinical efficacy of ET in pediatric patients with UTIs caused by an E.coli strain that turned out to be resistant to the ET in vitro (inappropriate ET, IET), to that of patients treated with an appropriate ET (AET), according to the antimicrobial susceptibility testing (AST) results.

Methods

We conducted a retrospective study on pediatric patients admitted to our Pediatric ward for an E.coli febrile UTI, over the period 2016-2020. The clinical efficacy of ET was assessed as time to defervescence, improvement of inflammatory blood markers, length of hospitalization (LOH), need of antibiotic prophylaxis and short and long-term complications.

Results

We enrolled 106 patients (median [IQR] age: 6.0 [3.0-14.3] months). Twenty-one (19.8%) patients underwent an IET. The comparison between IET and AET groups did not show any statically significant difference in terms of clinical efficacy. Within the IET group we compared patients who underwent a switch of the therapy, according to AST results, to those who did not. Within these 2 subgroups, 8/13 (61.5%) and 8/8 (100%) patients, respectively had defervescence before AST results. No differences were found in terms of clinical efficacy, except for the LOH as expected.

Conclusions

According to our findings, in vitro resistance of E.coli to ET did not affect the clinical outcome of pediatric patients with febrile UTIs who underwent an IET.