Optochin Susceptibility Research Articles

Identification and characterization of a novel α-haemolytic streptococci, Streptococcus parapneumoniae sp. nov., which caused bacteremia with pyelonephritis

ObjectivesWe report a case of bacteremia with pyelonephritis in an adult male with an underlying disease caused by α-hemolytic streptococci. α-Hemolytic streptococci were isolated from blood, but it was challenging to identify its species. This study aimed to characterize the causative bacterium SP4011 and to elucidate its species. MethodsThe whole-genome sequence and biochemical characteristics of SP4011 were determined. Based on the genome sequence, phylogenetic analysis was performed with standard strains of each species of α-hemolytic streptococci. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values were calculated. ResultsSP4011 showed optochin susceptibility and bile solubility, but did not react with pneumococcal omni antiserum. Phylogenetic analysis of the whole-genome sequence showed that SP4011 clustered with S. pneumoniae and S. pseodopneumoniae and was most closely related to S. pseodopneumoniae. Genomic analysis revealed that ANI and dDDH values between SP4011 and S. pseodopneumoniae were 94.0 % and 56.0 %, respectively, and between SP4011 and S. pneumoniae were 93.3 % and 52.2 %, respectively. Biochemical characteristics also showed differences between SP4011 and S. pseodopneumoniae and between SP4011 and S. pneumoniae. These results indicate that SP4011 is a novel species. ConclusionOur findings indicate that SP4011 is a novel species of the genus Streptococcus. SP4011 has biochemical characteristics similar to S. pneumoniae, making it challenging to differentiate and requiring careful clinical diagnosis. This isolate was proposed to be a novel species, Streptococcus parapneumoniae sp. nov. The strain type is SP4011T (= JCM 36068T = KCTC 21228T).

Accurate identification of Streptococcus pseudopneumoniae and other mitis group Streptococci identified as atypical Streptococcus pneumoniae in Tunisian pediatric population.

Accurate identification of Mitis group streptococci especially Streptococcus pneumoniae and Streptococcus pseudopneumoniae seems difficult due to the lack of specific and sensitive tests. We performed an approach for the identification of atypical pneumococci in pediatric Tunisian population. In this study, 49 streptococcal isolates that were considered as atypical S. pneumoniae were analyzed by: optochin susceptibility in ambient and 5% CO2 atmosphere, oxgall disk sensitivity, PCR targeting several genes and antimicrobial susceptibility.The combined results of biochemical and molecular methods showed the presence of 23 S. pneumoniae, 7 S. pseudopneumoniae, and 19 other mitis group. Among S. pseudopneumoniae, all isolates were collected from respiratory tract samples and showed a high level of resistance to β-lactams with a MIC90 of 32 mg L-1. Two isolates of S. pseudopneumoniae showed the typical phenotype of optochin resistance described in the literature. All isolates could be identified only by molecular tests. Among Streptococcus pneumonaie, all strains harbored the lytA gene and the Spn9802 fragment. But only 14 strains were encapsulated.This study describes several assays for the identification of atypical pneumococci in order to gain insights on the nature of isolate and raise alert about the presence of these strains in the pediatric Tunisian community.

Nasopharyngeal Carriage Rate of Streptococcus pneumoniae, Related Risk Factors, and Antibiotic Susceptibility Among Inmates in Hawassa Central Prison Institute: Hawassa, Sidama National Region, Ethiopia.

The bacterium Streptococcus pneumoniae commonly causes severe bacterial illnesses in both children and adults. S. pneumoniae is the most fatal bacterial pathogen, causing 50% of the deaths from lower respiratory infections in people of all ages. This study was aimed to determine a nasopharyngeal carriage rate of S. pneumoniae, related risk factors, and antibiotic susceptibility among prisoners in Hawassa Central Prison Institute Hawassa, Ethiopia. From July to August 2021, a cross-sectional investigation was carried out in Hawassa prison. All randomly chosen adult volunteers were a part of the study. In this study, about 330 different people were included. Within 3 h of collection, the swab specimen was inoculated onto 5% sheep blood agar; the inoculated medium was then incubated for 18-24 h at 35-37 °C in a CO2-enriched environment. Following incubation, the S. pneumoniae colonies were suspected, but the usual colony shape, alpha-hemolysis, Gram staining, optochin susceptibility, and bile solubility test allowed for confirmation. Antimicrobial susceptibility testing was carried out in accordance with the Clinical and Laboratory Standards Institute's guidelines. Overall carriage rate of S. pneumoniae among adult individuals were 41 (12.7%). The carriage rate of S. pneumoniae was affected by age classes that 39-48 years (OR = 4.82, 95%CI = 1.49-15.56, p = .009), 49-58 years (OR = 5.27, 95%CI = 1.27-21.89, p = .022), and greater than 58 years (OR = 4.36, 95%CI = 1.13-16.90, p = .033); cigarette smoking (OR = 3.41, 95%CI = 1.16-10.01, p = .026); and sharing beds (OR = 3.91, 95%CI = 1.27-12.07, p = .018). The majority of the isolates are susceptible for clindamycin (87.8%) and resistant for chloramphenicol (56%). Multidrug resistance was observed in 36.7%. The overall carriage rate of S. pneumoniae was 12.7%. Age, cigarette smoking, and sharing beds in the same prison room had a substantial impact on this nasopharyngeal carriage rate. Chloramphenicol (56%), erythromycin (41.5%), tetracycline (39%), and co-trimoxazole (34.1%) resistance were seen in the majority of S. pneumoniae isolates. Early detection, hygiene maintenance, and appropriate treatment are necessary.

Streptococcus pseudopneumoniae as an emerging respiratory tract pathogen at Assiut University hospitals.

Streptococcus pseudopneumoniae is a member of viridans streptococci. It is non-capsulated, bile insoluble and optochin susceptible in ambient air but resistant in 5% CO2. This study aimed to isolate S. pseudopneumoniae from sputum specimens of patients admitted to Chest Department and Chest ICU of Assiut University hospitals, differentiate it from Streptococcus pneumoniae in addition, to evaluate the prevalence of Streptococcus pseudopneumoniae in clinical isolates by phenotypic and genotypic methods, to subject the isolates to antimicrobial susceptibility testing using agar disc diffusion method. Isolation of Streptococcus pseudopneumoniae from sputum sample and doing phenotypic test (optochin susceptibility test,bile susceptibility test and antimicrobial susceptibility test) and genotypic test by polymerase chain reaction (PCR) for five genes: CpsA, LytA, AliB-like ORF2, 16S rRNA and Spn9802 genes. Twenty isolates of S. pseudopneumoniae were diagnosed phenotypically by optochin susceptibility and bile solubility tests followed by genotypic characterization by polymerase chain reaction (PCR) for five genes: CpsA, LytA, AliB-like ORF2, 16S rRNA and Spn9802 genes. The prevalence of S. pseudopneumoniae among studied patients was 10% (20/200). The pure growth of S. pseudopneumoniae from sputum samples together with the great percentage of antibiotic resistance should raise attention to the clinical importance of this organism.

Prevalence and Multi-Drug Resistance of Streptococcus pneumoniae Infection Among Presumptive Tuberculosis Adult Cases at Dilla University Referral Hospital, Dilla, Ethiopia.

IntroductionStreptococcus pneumoniae is the leading cause of community-acquired pneumonia in Africa. The simultaneous occurrence of both infections leads to delayed diagnosis and inadequate treatment. The study aimed to determine the prevalence, antimicrobial susceptibility pattern and associated factors of Streptococcus pneumoniae infection among presumptive Tuberculosis adult cases at Dilla University Referral Hospital, Dilla, Ethiopia.MethodsAn institution-based cross-sectional study was conducted on 422 presumptive TB cases visiting TB clinic at Dilla University Referral Hospital from April to June 2021. Following the Bartlett’s criteria, the accepted sputum samples were cultured on Blood agar plate and chocolate agar plate. Streptococcus pneumoniae was identified and confirmed by typical colony morphology, alpha-hemolysis, gram staining, optochin susceptibility and bile solubility tests. Antimicrobial susceptibility test was done by using the Kirby-Bauer disc diffusion method. Semi-structured questionnaires were used to collect data. Bivariate and multivariate logistic regression analyses were done by using SPSS version 23.0, computer software.ResultsThe overall prevalence of S. pneumoniae in presumptive tuberculosis adult cases was 21.4% (95% CI: 17.7–25.5). S. pneumoniae has a high level of resistance to penicillin (74.1%), tetracycline (78.7%) and Trimethoprim-sulfamethoxazole (46%). Multidrug resistance was observed in 46.1% of bacterial isolates. Being primary education, more than five family size and one or two rooms in the house had more likely to cause S. pneumoniae infection.ConclusionThis study revealed a relatively high prevalence of multidrug resistance of Streptococcus pneumoniae infection. Primary educational status, living in a crowded family, below two rooms in the house, had a significant association with S. pneumoniae infection.

Nasopharyngeal carriage rate, serotype distribution, and antimicrobial susceptibility profile of Streptococcus pneumoniae isolated from children under five years old in Kotabaru, South Kalimantan, Indonesia.

Streptococcus pneumoniae is a bacterial pathogen that colonizes the human nasopharynx. Colonization is frequently reported to be high in young children. In this study, we investigated the nasopharyngeal (NP) carriage rate, serotype distribution, and antibiotic susceptibility of S. pneumoniae in children under five years of age in Kotabaru, South Kalimantan, Indonesia. NP swab specimens were collected from 399 young children (mean age: 30 months) who participated in the Rampa Village Community Health Center, with 74% of the participants being Bajau children. S. pneumoniae was identified using optochin susceptibility and bile solubility tests. Serotyping was performed by sequential multiplex PCR, and antimicrobial susceptibility profiling was performed by disk diffusion and microdilution methods. The NP carriage rate of S. pneumoniae was 45% (180/399). The most commonly serotypes were 6A/6B (18%), followed by 15B/15C (17%), 19F (16%), 34 (8%), and 23F (5%); 46% of them were identified as strains of the PCV13 vaccine type. Additionally, almost half of the pneumococcal isolates were non-susceptible to penicillin (40%), whereas non-susceptibility to tetracycline (36.8%), trimethoprim/sulfamethoxazole (29.7%), erythromycin (16.8%), chloramphenicol (9.7%), and clindamycin (8.6%) was also found. We identified 18% (n=34) of S. pneumoniae isolates as multidrug-resistant (MDR) strains, and serotype 19F was the most common (74%) among them. MDR S. pneumoniae vaccine type strains were dominated by serotype 19F. The implementation of a pneumococcal conjugate vaccine program in Indonesia might reduce MDR strains circulating in the community in the future.

MALDI-TOF Mass Spectrometry-Based Optochin Susceptibility Testing for Differentiation of Streptococcus pneumoniae from other Streptococcus mitis Group Streptococci.

Discrimination of Streptococcus pneumoniae from other Streptococcus mitis group (SMG) species is still challenging but very important due to their different pathogenic potential. In this study, we aimed to develop a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based optochin susceptibility test with an objective read-out. Optimal test performance was established and evaluated by testing consecutively collected respiratory isolates. Optochin in different concentrations as a potential breakpoint concentration was added to a standardized inoculum. Droplets of 6 µL with optochin and, as growth control, without optochin were spotted onto a MALDI target. Targets were incubated in a humidity chamber, followed by medium removal and on-target protein extraction with formic acid before adding matrix with an internal standard. Spectra were acquired, and results were interpreted as S. pneumoniae in the case of optochin susceptibility (no growth), or as non-S. pneumoniae in the case of optochin non-susceptibility (growth). Highest test accuracy was achieved after 20 h incubation time (95.7%). Rapid testing after 12 h incubation time (optochin breakpoint 2 µg/mL; correct classification 100%, validity 62.5%) requires improvement by optimization of assay conditions. The feasibility of the MALDI-TOF MS-based optochin susceptibility test was demonstrated in this proof-of-principle study; however, confirmation and further improvements are warranted.

Clinical optochin resistant Streptococcus pneumoniae and Streptococcus pseudopneumoniae strains in Tunisia.

Streptococcus pneumoniae can be responsible for severe human infections. Optochin resistance has been a potential cause of misidentification of pneumococcus and other members of the mitis group. Hence, rapid and easy optochin resistant (Optr) S. pneumoniae identification is essential. Atypical pneumococci were characterized using optochin susceptibility, bile solubility based on spectrophotometric reading, serotyping, pulsed field gel electrophoresis (PFGE), 16S rRNA sequencing and PCR-based assays targeting pneumococcal genes lytA, ply, pspA, cpsA, Spn9802 and Spn9828. Optical density values for the bile solubility test suggest the identification of four Optr S. pneumoniae and one Streptococcus pseudopneumoniae. All Optr pneumococci harbored cpsA, lytA, ply, Spn9802, Spn9828 and pspA genes. Only ply, spn9802 and Spn9828 genes were detected in S. pseudopneumoniae. The 16S rRNA sequencing differentiates between these two species. Optr S. pneumoniae strains belonged to different genotypes and serotypes (14, 19A, 3 and 9V). Three Optr S. pneumoniae isolates were typed as pspA family 2, while one belonged to pspA family 1. Sequencing of the atpA and atpC gene of the Optr variants revealed three mutations in the ATPase a-subunit (L99I, M23V and V52I) and one mutation in ATPase c-subunit (V48I). Our data indicate that bile OD-values provides an accurate, fast and easy method to discriminate between Optr S. pneumoniae and other Streptococcus mitis group. Moreover molecular techniques, confirming the bile test, can be used in order to prevent these atypical pneumococci and alert clinical microbiologists of the presence of these strains in the community.

Antimicrobial resistance profile and multidrug resistance patterns of Streptococcus pneumoniae isolates from patients suspected of pneumococcal infections in Ethiopia

BackgroundAntimicrobial-resistant strains of Streptococcus pneumoniae have become one of the greatest challenges to global public health today and inappropriate use of antibiotics and high level of antibiotic use is probably the main factor driving the emergence of resistance worldwide. The aim of this study is, therefore, to assess the antimicrobial resistance profiles and multidrug resistance patterns of S. pneumoniae isolates from patients suspected of pneumococcal infections in Ethiopia.MethodsA hospital-based prospective study was conducted from January 2018 to December 2019 at Addis Ababa city and Amhara National Region State Referral Hospitals. Antimicrobial resistance tests were performed from isolates of S. pneumoniae that were collected from pediatric and adult patients. Samples (cerebrospinal fluid, blood, sputum, eye discharge, ear discharge, and pleural and peritoneal fluids) from all collection sites were initially cultured on 5% sheep blood agar plates and incubated overnight at 37 °C in a 5% CO2 atmosphere. Streptococcus pneumoniae was identified and confirmed by typical colony morphology, alpha-hemolysis, Gram staining, optochin susceptibility, and bile solubility test. Drug resistance testing was performed using the E-test method according to recommendations of the Clinical and Laboratory Standards Institute.ResultsOf the 57 isolates, 17.5% were fully resistant to penicillin. The corresponding value for both cefotaxime and ceftriaxone was 1.8%. Resistance rates to erythromycin, clindamycin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole were 59.6%, 17.5%, 38.6%, 17.5 and 24.6%, respectively. Multidrug resistance (MDR) was seen in 33.3% isolates. The most common pattern was co-resistance to penicillin, erythromycin, clindamycin, and tetracycline.ConclusionsMost S. pneumoniae isolates were susceptible to ceftriaxone and cefotaxime. Penicillin has been used as a drug of choice for treating S. pneumoniae infection. However, antimicrobial resistance including multidrug resistance was observed to several commonly used antibiotics including penicillin. Hence, it is important to periodically monitor the antimicrobial resistance patterns to select empirical treatments for better management of pneumococcal infection.

Description of optochin-resistant Streptococcus pneumoniae due to an uncommon mutation in the atpA gene and comparison with previously identified atpC mutants from Brazil

Optochin susceptibility testing is a major assay used for presumptive identification of Streptococcus pneumoniae. Still, atypical optochin-resistant (Optr) pneumococci have been reported and this phenotype has been attributed to nucleotide substitutions in the genes coding for the F0F1ATPase. While substitutions in the atpC gene (c-subunit of ATPase) are more common and better characterized, data on mutations in the atpA (a-subunit) are still limited. We have characterized five Optr isolates presenting alterations in the atpA (Trp206Cys in four isolates and Trp206Ser in one isolate), constituting the first report of such mutations in Brazil. Most of the Optr isolates consisted of heterogeneous populations. Except for Opt MICs and the nucleotide changes in the atpA gene, Optr and Opts subpopulations originating from the same culture had identical characteristics. In addition, we compared phenotypic and genetic characteristics of these atpA mutants with those of atpC mutants previously identified in Brazil. No structural alterations were detected among predicted proteins, regardless of mutations in the coding gene, suggesting that, despite the occurrence of mutations, protein structures tend to be highly conserved, ensuring their functionalities. Phylogenetic analysis revealed that atypical Optr strains are true pneumococci and Opt resistance does not represent any apparent selective advantage for clinical isolates.

Assessment of the Optochin Susceptibility Test to Differentiate Streptococcus pneumoniae from other Viridans Group Streptococci.

Streptococcus pneumoniae identification has traditionally been based on two biochemical tests, susceptibility of pneumococci to optochin and solubility in bile-salt solution. Due to slowness and sometimes difficulty in interpretation, the bile solubility test has fallen into disuse. The main objective of this work was to assess the current effectiveness of the optochin susceptibility test in pneumococcal identification in clinical practice. Overall 126 viridans group streptococci consecutively isolated from respiratory samples were analyzed using the optochin susceptibility test by picking one colony from the culture. Sixty-two were initially considered optochin susceptible, and 64 were considered optochin resistant and analyzed with the bile solubility test. If a discrepancy between the tests was observed (i.e., whether an isolate was optochin susceptible and bile insoluble or optochin resistant and bile soluble), then the optochin susceptibility test was repeated, adjusting the inoculum to a McFarland standard of 0.5. Species were identified by sequencing the lytA and recA genes. Twelve discrepancies were initially observed. The result of the repeated optochin test showed that the initial optochin test of 4 isolates had been wrongly interpreted. Of the remaining 8 discrepancies, 2 optochin-resistant bile-soluble isolates were identified by gene sequencing as S. pneumoniae, and of the 6 optochin-susceptible bile-nonsoluble isolates, 3 were identified as Streptococcus mitis and 3 as Streptococcus pseudopneumoniae. The optochin test correctly identified 90.5% of all recent viridans group streptococci clinical isolates which include both optochin susceptible (62/126 = 49.2%) and optochin resistant (64/126 = 50.8%) strains. Of the group of optochin susceptible viridans, 87.5% were correctly identified, and 93.5% of the optochin resistant group were correctly identified. However, this technique does not correctly differentiate between S. pneumoniae from other viridans group streptococci in the clinical setting. Additional testing is needed for that identification.

Prevalence of pneumococcal nasopharyngeal colonization and serotypes circulating in Cameroonian children after the 13-valent pneumococcal conjugate vaccine introduction

BackgroundStreptococcus pneumoniae remains a major contributor to childhood infections and deaths globally. In Cameroon, the 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in July 2011, using a 3-dose Expanded programme on immunization (EPI) schedule administered to infants at 6, 10 and 14 weeks of age. To evaluate PCV13 effects, we assessed pneumococcal nasopharyngeal colonization and serotype distribution among Cameroonian children after PCV13 introduction. MethodsNasopharyngeal (NP) swabs were collected from eligible children aged 24–36 months in two cross-sectional surveys conducted from March to July: in 2013 (PCV13-unvaccinated), and in 2015 (PCV13-vaccinated). Using a systematic World Health Organization (WHO) cluster coverage sampling technique in 40 communities, NP swabs collected were processed following WHO recommendations. Standard bacterial culture techniques were used for the isolation of S. pneumoniae from gentamicin-blood agar plates and identification using optochin susceptibility testing. Serotyping was performed using sequential multiplex polymerase chain reaction, supplemented with Quellung test. ResultsAmong the PCV13-vaccinated children, overall pneumococcal carriage prevalence was 61.8% (426/689) and PCV13 vaccine-type carriage prevalence was 18.0% (123/689). Eleven out of the 13 vaccine serotypes were detected in the vaccinated children. The most common serotypes were 19F (4.5%, 31/689) and 15B/C (7.3%, 50/689). ConclusionIn Cameroon, four years after infant vaccination nearly all of the PCV13-serotypes continued to circulate in the population. This suggests that the direct and indirect effects of the vaccination programme have not resulted in expected low levels of vaccine-type transmission. Continuous monitoring is needed to assess the long term effects of the PCV13 on nasopharyngeal carriage and disease.

Relationships among streptococci from the mitis group, misidentified as Streptococcus pneumoniae

The aim of our study was to investigate phenotypic and genotypic features of streptococci misidentified (misID) as Streptococcus pneumoniae, obtained over 20 years from hospital patients in Poland. Sixty-three isolates demonstrating microbiological features typical for pneumococci (optochin susceptibility and/or bile solubility) were investigated by phenotypic tests, lytA and 16S rRNA gene polymorphism and whole-genome sequencing (WGS). All isolates had a 6-bp deletion in the lytA 3′ terminus, characteristic for Mitis streptococc and all but two isolates lacked the pneumococcal signature cytosine at nucleotide position 203 in the 16S rRNA genes. The counterparts of psaA and ply were present in 100% and 81.0% of isolates, respectively; the spn9802 and spn9828 loci were characteristic for 49.2% and 38.1% of isolates, respectively. Phylogenetic trees and networks, based on the multilocus sequence analysis (MLSA) scheme, ribosomal multilocus sequence typing (rMLST) scheme and core-genome analysis, clearly separated investigated isolates from S. pneumoniae and demonstrated the polyclonal character of misID streptococci, associated with the Streptococcus pseudopneumoniae and Streptococcus mitis groups. While the S. pseudopneumoniae clade was relatively well defined in all three analyses, only the core-genome analysis revealed the presence of another cluster comprising a fraction of misID streptococci and a strain proposed elsewhere as a representative of a novel species in the Mitis group. Our findings point to complex phylogenetic and taxonomic relationships among S. mitis-like bacteria and support the notion that this group may in fact consist of several distinct species.

Characterization and distribution of viridans group streptococci isolated from infectious endophthalmitis and keratitis.

The aims of this study were to characterize alpha-hemolytic streptococci among isolates from cases of infectious endophthalmitis and keratitis and to determine their distributions. The sample included 27 and 35 nonduplicated isolates of alpha-hemolytic streptococci recovered from patients with infectious endophthalmitis (2002-2013) and keratitis (2008-2013), respectively. Isolates were identified by the optochin susceptibility and bile solubility tests, using a biochemical identification system. The minimum inhibitory concentration was determined by the broth microdilution method. Molecular identification was performed by analyses of three constitutive genes and the complementary multilocus sequence. The molecular epidemiology of Streptococcus pneumoniae was investigated using multilocus sequence typing, and the presence of the capsular polysaccharide-encoding gene was assessed using conventional polymerase chain reaction. Outcomes were evaluated using the patients' medical records. Phenotypic tests differentiated S. pneumoniae from other alpha-hemolytic streptococci, consistent with later molecular identifications. Streptococcus oralis was significantly prevalent among the endophthalmitis isolates, as was S. pneumoniae in the keratitis isolates. High levels of susceptibility to antibiotics were observed, including vancomycin, cephalosporins, and fluoroquinolones. High genetic variability was detected among the 19 S. pneumoniae strains, with 15 predicted to be encapsulated. The medical records of patients with infectious endophthalmitis were reviewed (n=15/27; 56%), and final visual acuity was assessed in 12 cases (44%). Many patients progressed to a final visual acuity state of "no light perception" (6/12; 50%), "light perception" (3/12; 25%), or "hand motion" (1/12; 8%). The medical records of patients with infectious keratitis were also reviewed (n=24/35; 69%), and final visual acuity was assessed in 18 cases (51%). Similarly, most patients progressed to a final visual acuity state of "no light perception" (6/18; 33%), "light perception" (1/18; 6%), or "hand motion" (6/18; 33%). Overall, the majority of patients progressed to a final visual acuity state of "no light perception" (12/30), "light perception" (4/30), or "hand motion" (7/30). The distribution of alpha-hemolytic streptococci in ocular infections suggested the presence of a species-specific tissue tropism. The prognoses of patients with ocular streptococcal infections were highly unfavorable, and antibiotic resistance did not contribute to the unfavorable clinical progressions and poor outcomes.

The Air Quality and Detection of Streptococcus pneumoniae in the Pediatric Ward of Dr. Hasan Sadikin Hospital Bandung

Background : Nosocomial infection can be acquired by inhalation of droplets from contaminated air. In children, nosocomial pneumonia is mainly caused by Streptococcus pneumoniae. This study aimed to explore the air quality level and to detect Streptococcus pneumonia in the air of the Pediatric Ward of Dr. Hasan Sadikin Hospital, Bandung. Methods : This was an observational descriptive study conducted in the Pediatric Ward of Dr. Hasan Sadikin Hospital in November 2012. The different number of modified tryptic soy agar (TSA) plates with 4% blood were exposed and placed in various rooms of the ward for 30 minutes between 12.00 pm to 1.00 pm at heights between 1.0m to 1.5m and according to the respectively room air volume. After exposure, these plates were then incubated for 48 hours at 35°C. The Colony Forming Units (CFU) on each plate was counted per Replicate Organism Detection and Counting (RODACTM). Detection of Streptococcus pneumonia was performed by detecting any round α-hemolytic colonies on the TSA plate, confirmed by Gram staining, optochin susceptibility test, and the bile solubility test. Result : The air quality in 13 rooms of the Pediatric Ward was generally poor ranging from 27.5 to 232.0 CFU/30 min, however, the concentration of microorganisms per cubic meter air was from 0.198 to 4.296 CFU/m3. Moreover, Streptococcus pneumoniae was not present in the air of the ward. Conclusions : Although Streptococcus pneumoniae has not been detected, the air quality in the Pediatric Ward of Dr. Hasan Sadikin Hospital, Bandung is generally poor. General precautions need to be enhanced to increase the air quality in the hospital.

1999. Performance of Pneumococcal Urinary Antigen Testing: Riding the Vaccination Waves?

BackgroundUrinary antigen testing for Streptococcus pneumoniae (PAgT) is simple, rapid, and can still be used days after initiation of antibiotic therapy or when conventional methods are failing. PAgT is recommended by international guidelines in severe community acquired pneumonia (CAP). The test attains an excellent specificity (>90%) in adults but shows a varying sensitivity (60–85%). We aimed to analyze the PAgT sensitivity in a population with blood culture proven invasive pneumococcal disease (IPD) and to study its performance for the different pneumococcal serotypes.MethodsPAgT (BinaxNOW®, Alere®) was introduced in 2009 in a large secondary care hospital in Ghent, Belgium. PAgT is requested by the attending physician or the clinical microbiologist in case of IPD suspicion. Pneumococci from blood are identified by standard methods (optochin susceptibility and bile solubility) and serotyped by the national reference center. Overall PAgT performance and test sensitivity for different serotypes were calculated.ResultsOver a 9-year period, (2009–2017), 235 bacteremia episodes in 234 patients were observed with an average of 26 episodes/year (range 12–36). 31/235 (13%) episodes occurred in pediatric patients. Most prevalent serotypes were 1, 12, 8, 3, 7, 9, 5, and 6 for the whole time period. PAgT was performed in 161/235 (69%), test execution for the individual most prevalent serotypes ranged from 55 to 86%. 99/161(61%) PAgT were positive. PAgT positive results varied according to the most prevalent serotypes: >70% for types 1, 3, 7and 5, 50% for type 9 and <50% for types 12, 8 and 6. From 2014 on, disappearance of serotype 1 and a significant decrease in serotype 7 were observed.ConclusionA 70% compliance to the diagnostic algorithm for IPD was observed. PAgT detects C-polysaccharide (teichoic acid) on the pneumococcal cell wall. Differences in concentration for the individual serotypes have been described and may account for the varying sensitivity in our dataset. Introduction of 10/13-valent childhood pneumococcal vaccines (2014) in Belgium has changed the overall serotype distribution, also possibly leading to a shift in PAgT performance. A dynamic validation of PAgT accuracy remains warranted.Disclosures All authors: No reported disclosures.

Description of a novel mutation in the atpC gene in optochin-resistant Streptococcus pneumoniae strains isolates from Tunisia

Identification of Streptococcus pneumoniae among other α-haemolytic streptococci is based on phenotypic or genotypic characteristics such as colony morphology, bile solubility and optochin susceptibility. This study reports three optochin-resistant S. pneumoniae strains isolated from immunocompromised patients in Tunisia. The three isolates were positive for the bile solubility test. Biochemical identification with API® 20 Strep was not discriminatory for two strains. The three strains had different serotypes (6C, 19F and 23F) and three different sequence types (ST386, ST320 and ST326). Sequencing of the atpA and atpC genes for each strain showed only modification in atpC. The mutations Met13→Val or Val48→Ile were observed in two strains. However, in the third strain a novel type of mutation (Val15→Ile) was identified.

Characterization of Streptococcus pneumoniae isolates from Austrian companion animals and horses

BackgroundThe aim of the present study was to investigate the genetic relatedness and the antimicrobial resistance profiles of a collection of Austrian Streptococcus pneumoniae isolates from companion animals and horses. A total of 12 non-repetitive isolates presumptively identified as S. pneumoniae were obtained during routinely diagnostic activities between March 2009 and January 2017.ResultsIsolates were confirmed as S. pneumoniae by bile solubility and optochin susceptibility testing, matrix-assisted laser desorption-ionization-time of flight (MALDI-TOF) mass spectrometry and sequence analysis of a part recA and the 16S rRNA genes. Isolates were further characterized by pneumolysin polymerase chain reaction (PCR) and genotyped by multilocus sequence typing (MLST). Antimicrobial susceptibility testing was performed and resistance genes were detected by specific PCR assays. All isolates were serotyped. Four sequence types (ST) (ST36, ST3546, ST6934 and ST6937) and four serotypes (3, 19A, 19F and 23F) were detected. Two isolates from twelve displayed a multidrug-resistance pheno- and genotype.ConclusionsThis study represents the first comprehensive investigation on characteristics of S. pneumoniae isolates recovered from Austrian companion animals and horses. The obtained results indicate that common human sero- (23F) and sequence type (ST36) implicated in causing invasive pneumococcal disease (IPD) may circulate in dogs. Isolates obtained from other examined animals seem to be host-adapted.

English

Streptococcus pseudopneumoniae is a mischaracterized species of Streptococci that is usually overlooked during examination of sputum samples of patients with chest infections. The association of this organism with lower respiratory tract diseases is still unclear and its isolation and description is underestimated in our locality. To our knowledge, there are no published studies on the isolation of S. pseudopneumoniae from pathological specimens in Egypt. The aims of this study were to isolate S. pseudopneumoniae from sputum specimens of patients admitted to Chest Department of Mansoura University Hospitals (MUHs) and to differentiate it from Streptococcus pneumoniae and other viridans group Streptococci, also to determine its prevalence and associated risk factors. Sixteen isolates of S. pseudopneumoniae were diagnosed phenotypically by optochin susceptibility and bile solubility tests followed by genotypic characterization by multiplex polymerase chain reaction (PCR). All of the isolates were subjected to antibiotic susceptibility testing using the disk diffusion method. The prevalence of S. pseudopneumoniae among studied patients was 4.9% (16/329). All of the examined isolates were found to be positive for aliB-like ORF2 and negative for cpsA and lytA genes by multiplex PCR. Elevated resistance rate of the isolates was recorded for erythromycin, penicillin and co-trimoxazole. Infection by S. pseudopneumoniae was found to be significantly associated with Chronic Obstructive Pulmonary Diseases (COPD). Although, S. pseudopneumoniae recorded a low prevalence in this study, their elevated antibiotic resistance together with the association with COPD and their pure isolation from sputum samples underline the necessity of spending more effort for their detection and characterization in the microbiology laboratories. Key words: Chronic obstructive pulmonary diseases (COPD), optochin, respiratory diseases, Streptococcus pseudopneumoniae.

Patterns of infections, aetiological agents and antimicrobial resistance at a tertiary care hospital in northern Tanzania.

To determine the causative agents of infections and their antimicrobial susceptibility at a tertiary care hospital in Moshi, Tanzania, to guide optimal treatment. A total of 590 specimens (stool (56), sputum (122), blood (126) and wound swabs (286)) were collected from 575 patients admitted in the medical and surgical departments. The bacterial species were determined by conventional methods, and disc diffusion was used to determine the antimicrobial susceptibility pattern of the bacterial isolates. A total of 249 (42.2%) specimens were culture-positive yielding a total of 377 isolates. A wide range of bacteria was isolated, the most predominant being Gram-negative bacteria: Proteus spp. (n = 48, 12.7%), Escherichia coli (n = 44, 11.7%), Pseudomonas spp. (n = 40, 10.6%) and Klebsiella spp (n = 38, 10.1%). Wound infections were characterised by multiple isolates (n = 293, 77.7%), with the most frequent being Proteus spp. (n = 44, 15%), Pseudomonas (n = 37, 12.6%), Staphylococcus (n = 29, 9.9%) and Klebsiella spp. (n = 28, 9.6%). All Staphylococcus aureus tested were resistant to penicillin (n = 22, 100%) and susceptible to vancomycin. Significant resistance to cephalosporins such as cefazolin (n = 62, 72.9%), ceftriaxone (n = 44, 51.8%) and ceftazidime (n = 40, 37.4%) was observed in Gram-negative bacteria, as well as resistance to cefoxitin (n = 6, 27.3%) in S. aureus. The study has revealed a wide range of causative agents, with an alarming rate of resistance to the commonly used antimicrobial agents. Furthermore, the bacterial spectrum differs from those often observed in high-income countries. This highlights the imperative of regular generation of data on aetiological agents and their antimicrobial susceptibility patterns especially in infectious disease endemic settings. The key steps would be to ensure the diagnostic capacity at a sufficient number of sites and implement structures to routinely exchange, compare, analyse and report data. Sentinel sites (hospitals) across the country (and region) should report on a representative subset of bacterial species and their susceptibility to drugs at least annually. A central organising body should collate the data and report to relevant national and international stakeholders.