184. Inducible Clindamycin Resistance Testing on Pediatric Streptococcus pneumoniae Isolates

Background In 2013, the Clinical and Laboratory Standards Institute recommended inducible clindamycin resistance (ICR) testing on macrolide-resistant Streptococcus pneumoniae isolates, which arises due to the ermB gene. Ribosomal methylation by ermB confers resistance to macrolides (high-level resistance), lincosamides and streptogramin B. The goal of our study is to characterize the prevalence of ICR among pediatric pneumococcal isolates. Methods We identified erythromycin-resistant(R) (minimum inhibitory concentration [MIC] ≥ 1 µg/mL) and clindamycin-susceptible(S) (MIC ≤ 0.25 µg/mL) pneumococcal isolates from pediatric patients seen at Children’s Mercy Hospital from 2007 to 2017. Determination of ICR was achieved via disk approximation (D-zone test) with standard erythromycin (15 µg) and clindamycin (2 µg) disks. Isolates with high-level erythromycin resistance (MIC ≥ 32µg/mL) were also tested for ermB gene by PCR. Positive and negative controls were used for D-zone test and ermB PCR. Results We identified 289 erythromycin-R pneumococcal isolates; of those 194 (67.1%) were clindamycin-S (Figure 1). One-hundred and sixty-nine isolates were available for ICR testing, 166 (98%) isolates represented non-invasive disease samples. Median age of patients with erythromycin-R and clindamycin-S isolates was 19 (range 0.1 – 180) months. None of the isolates expressed ICR based on the D-zone test. Thirteen of those isolates (7.7%) expressed high-level erythromycin-R (MIC range 32-128 µg/mL); all were negative for ermB. The most common serotypes/serogroups among erythromycin-R and clindamycin-S isolates were: 15 (n=22), 35B (n=19), 11 (n=16), 6 (n=16), 19A (n=14) and 33 (n=12). Conclusion Erythromycin-R and clindamycin-S pneumococcal isolates did not express ICR and isolates with high-level erythromycin-R did not carry ermB. Multicenter studies are needed to determine if ICR testing is required for macrolide-resistant pneumococcal isolates in the PCV13 era. Disclosures Liset Olarte, MD, MSc, GSK (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)Sanofi (Research Grant or Support) Douglas S. Swanson, MD, Merck (Research Grant or Support)Pfizer (Research Grant or Support)Sanofi (Research Grant or Support)

Antibiotic Resistant Pattern and Resistant Gene Identification of Staphylococcus aureus from Chicken Farm in Bogor

Chicken is one of the important protein source in Indonesia. Moreover, the largest population of chicken layer and poultry in Indonesia is known situated at West Java province with Bogor manicipality as the main producer. The aims of this study were to determine the antibiotic resistance pattern of Staphylococcus aureus isolated from poultry and layer farm in Bogor. The study also identified gene encoded the resistance. Cloacal swab samples were collected from chicken broiler and layer farm in Bogor manicipality. The samples were then cultured in Mannitol Salt Agar (MSA) medium to obtain S. aureus. Suspected colony was then confirmed by biochemical test. Positive strains were tested against several antibiotics and the diameter of clear zone arround of colony was interpreted based on Clinical and Laboratory Standard Institute. Furthermore, the DNA from resistant strains were then extracted, followed by detection of the resistance gene by using polymerase chain reaction (PCR) method. A total of 14 isolates of S. aureus were positive from poultry farm, and 15 isolates from layer farm. Most of all were resistant to tetracycline, ampicillin, oxytetracycline, erythromycin and nalidixic acid. On the other hands, several strains were sensitive to gentamycin and chloramphenicol. The study showed 28 isolates out of them were multi-drug resistant. Resistant gene such as blaTEM, gyrA and tetA were also identified in some isolates except for ErmB gene which was found in isolates originated from poultry farm. In conclussion, S. aureus in both farm showed mostly multi-drug resistant to several antibiotics which were supported by identification of resistant gene among isolates.

Infection and drug resistance of Streptococcus agalactiae among perinatal pregnant women in Xinjiang

Background: Group B streptococcus (Streptococcus agalactiae) is one of the most common pathogens causing meningitis, bacteremia and pneumonia. The drug resistance mechanisms of group B streptococcus in different countries and regions also show regional differences.Method: The study population was comprised of 1877 pregnant women of 34-38 weeks who underwent prenatal examination in the gynecology and obstetrics outpatient clinic of Xinjiang People's Hospital, between January 1, 2019 and January 31, 2020. Clinic specimens were collected and identified by the API bacteria Rapid Identification card for the downstream group B Streptococcus (Streptococcus agalactiae) isolation. Drug susceptibility of the Streptococcus agalactiae isolated was detected by Kirby-Bauer disk diffusion method. Macrolide–lincosamide–streptogramin B (MLSB) resistance was determined by D test. Real-time quantitative polymerase chain reaction and Gene sequencing was performed for the resistance genes ermA, ermB, mreA, erm (47), mefA/E and Lin B.Results: 149 Streptococcus agalactiae-positive strains were identified by clinical isolation, with a positive rate of 7.94%. Group B Streptococcus showed 100% susceptibility to linezolid, penicillin, vancomycin, meropenem, ampicillin, ceftriaxone, 44.97%, 35.57%, 56.38% and 29.53% susceptibility to levofloxacin, erythromycin, tetracycline and clindamycin, respectively. Among the 149 isolates, 127 strains showed macrolide resistance phenotype. The detection rate of intrinsic resistance phenotype (cMLS) was 40.94% (59/127), active efflux resistance phenotype (MS) 9.45% (12/127), and induced resistance phenotype (iMLS) 22.83% (29/127).Conclusion: The ermB gene-mediated 50s ribosome target site change co-existing with mreA gene for macrolide resistance efflux may play a major role in the mechanism of Streptococcus agalactiae resistance macrolide resistance of in perinatal women in Xinjiang. The change of 50s ribosomal target site mediated by ermB gene may be the main reason for drug cross-resistance.

Anatomical Site, Typing, Virulence Gene Profiling, Antimicrobial Susceptibility and Resistance Genes of Streptococcus suis Isolates Recovered from Pigs in Spain

A set of 207 Streptococcus suis isolates were collected from ten autonomous communities from Spain in 2019 to 2020 from pigs with meningitis, pneumonic lungs, arthritic joints or other swollen viscera, to a lesser extent. Thirteen capsular types were detected being the most prevalent serotype 2 (21.7%), followed by serotypes 1 (21.3%), 9 (19.3%) and 3 (6.3%). Serotypes 2 and 9 were recovered mainly from the central nervous system (CNS), while serotype 1 was isolated mostly from swollen joints and serotype 3 from the lungs. Twenty-five isolates (12.1%) could not be typed. The most prevalent pathotype was epf + mrp + sly + luxS (49 isolates, 23.8%), and it was related mainly to serotypes 1 and 2. Serotypes 1–3 and 9 were significantly associated with anatomical sites of isolation and virulence factors, serotype 9 (CNS) and serotypes 3 and 9 (lungs) being associated with virulence profiles without the epf gene. S. suis isolates showed globally high antimicrobial resistances, but ampicillin followed by spectinomycin and tiamulin resulted in the highest activities, while the greatest resistances were detected for sulphadimethoxine, tetracyclines, neomycin, clindamycin and macrolides. A total of 87.4% isolates were positive to the tetO gene, 62.4% to the ermB gene and 25.2% to the fexA gene, while 14.6% were positive to all three genes simultaneously. A significative association between isolate resistances to tetracyclines and macrolides and the resistance genes tested was established, except for phenicol resistance and the fexA gene. A set of 14 multiresistance patterns were obtained according to the number of antimicrobials to which the isolates were resistant, the resistances to 12 or more agents being the most prevalent ones. A remarkable amount of multiresistance profiles could be seen among the S. suis serotype 9 isolates.

Rapid diagnosis of acute respiratory infections by multiplex endpoint PCR technology

Introduction: The multiplex endpoint PCR technology offers a number of potential advantages, results are available in a matter of hours rather than days, the extreme sensibility facilitates detection of even minutes the amounts of pathogen DNA in clinical samples and the test is not significantly affected by prior administration of antibiotics. Aim: The aim of this work was to rapidly identify the antibiotic resistance the monitoring of pathogen growth at the patients admitted in Hospitalization Intensive Care Unit, with the diagnosis of Community Acquired Pneumonia, (CAP). Method: The Analyzer Unyvero™ Pneumonia Application was used in detection of pneumonia associated pathogens and their antibiotic resistance genes using the Pneumonia Unyvero™ System, following PCR pathogen species with sequencing of the amplified microbial DNA. Results: The main pathogens of community acquired pneumonia from the cohort study,36 cases, (20 males in mean age 35-66 years and 16 females in mean age 40-55 mean years), were Streptococcus pneumonia, (16 cases), Staphilococcus aureus, (10 cases), Klebsiella pneumonia (5 cases) and other important agents were “atypical”, such as Haemophilus Influenzae, Chlamidophilapneumonie and Moraxelacataralis. A case with Acinetobacter baumani and Proteus Sp. was also widely resistance to mefA gene / ermB gene as all cases of analyzed. The more frequency of genes resistant (29 cases) are ermA gene / ermC / ermB for Staphilococcus aureus and the gene tem+shv / gene / ctx-M with the Chromosomal mutation (7 cases), as gyrA83_87 Ecoli / Pseu for Klebsiella pneumonia agents. Also, most resistance antibiotics were Makrolides, (29 cases and Lincosamides (6 cases) and these cases have had the chromosomial integrates. The most resistance microbe, Pseudomonas aeruginosa (1 case), has been registered as multi drugs resistance [MDR]*. Conclusion: The Unyvero™ results have been available 2 days before the primary microbiology report and 3 days before the final confirmation results, obtained by microbiology culture. The Unyvero Analyzer only provides rapid data to support the therapeutic decision of currant medic.

Inducible clindamycin resistance in clinical isolates of staphylococcus aureus in Suez Canal University Hospital, Ismailia, Egypt

Introduction: The increasing incidence of methicillin resistance among Staphylococci has led to renewed interest in the usage of macrolide-lincosamide-streptogramin B (MLSB) antibiotics to treat S. aureus infections, with clindamycin being the preferable agent owing to its excellent pharmacokinetic properties. Inducible clindamycin resistance my lead to therapeutic failure. Aim: Detection of the prevalence of constitutive and inducible clindamycin resistance in clinical isolates of S. aureus to improve the clinical outcomes in patients. Methodology: A total of 176 non-duplicate staphylococcal isolates were isolated from different clinical samples. Methicillin resistance was detected using Cefoxitin disk diffusion (CDD) method. Phenotypic clindamycin resistance was performed for all isolates by D test. Polymerase Chain Reaction (PCR) assay were done for detection of erm resistance genes (ermA, ermB and ermC). Results: Out of 176 strains of S. aureus, 108 isolates (61.3%) were identified as MRSA. Erythromycin and clindamycin resistance was detected in 96 isolates (54.5%) and 68 isolates (38.6%) respectively. Clindamycin resistance (cMLSB) was significantly higher (p value < 0.001) in MRSA strains (56 isolates) compared to MSSA (12 isolates). Resistant genes were detected in 160 isolates (91%). The ermA gene was detected in 28 isolates (16%), the ermB gene was detected in 80 isolates (45.5%) (p < 0.001). Conclusions and recommendations: The frequency of constitutive and inducible clindamycin resistance in MRSA isolates emphasizes the need to use D test in routine antimicrobial susceptibility testing to detect the susceptibility to clindamycin as the inducible resistance phenotype can inhibit the action of clindamycin and affect the treatment efficacy.

Screening of erm Gene of Inducible Clindamycin Resistant Staphylococcus aureus

Antibiotic resistance exhibited by Staphylococcus aureus is a growing global concern. This work was undertaken to determine the prevalence rate of inducible clindamycin resistant S. aureus in nasal sample and detect ermB gene in the isolates with inducible clindamycin resistance. Nasal swabs were collected from the school children and cultured on Mannitol Salt Agar (MSA) and Blood Agar (BA) for observation of colony morphology. Gram staining and biochemical test (catalase, oxidase, O-F and coagulase) were performed for further identification of the bacteria. The Kirby-Bauer disc diffusion method using a cefoxitin disc (30 μg) was used to detect methicillin resistant S. aureus (MRSA). All, the MRSA isolates were tested for ermB gene by PCR amplification. Among 64 S. aureus isolates, 17 (26 %) were MRSA. The prevalence of Inducible clindamycin resistant S. aureus (iMLSB) isolates was 23.4 % in the S. aureus isolates. All the isolates of MRSA were resistant to penicillin, while 88.2 % were sensitive to gentamicin. The prevalence of ermB gene was 3.1 % in the total S. aureus isolates and 11.7 % MRSA showed the presence of this gene. Routinely performing a D-test in laboratory will guide the clinicians on the rationale use of clindamycin and improving hygienic practices can reduce the spread of inducible clindamycin resistance.

Isolation and comparative genomic analysis of reuterin-producing Lactobacillus reuteri from poultry gastrointestinal tract

Lactobacillus reuteri is a natural inhabitant of selected animal and human gastrointestinal tract (GIT). Certain strains have the capacity to transform glycerol to 3-hydroxypropionaldehyde (3-HPA), further excreted to form reuterin, a potent antimicrobial system. Reuterin-producing strains may be applied as a natural antimicrobial in feed to prevent pathogen colonization of animals, such as in poultry, and replace added antimicrobials. To date, only seven L. reuteri strains isolated from poultry have been characterized which limits phylogenetic studies and host-microbes interactions characterization. This study aimed to isolate L. reuteri strains from poultry GIT and to characterize their reuterin production and antimicrobial resistance (AMR) profiles using phenotypic and genetic methods. Seventy reuterin-producing strains were isolated from poultry crop, faeces and caeca and twenty-five selected for further characterization. Draft genomes were generated for the new 25 isolates and integrated in a phylogenetic tree of 40 strains from different hosts. Phylogenetic analysis based on gene content as well as on core genomes showed grouping of the selected 25 L. reuteri poultry isolates within the poultry/human lineage VI. Strains harbouring pdu-cob-cbi-hem genes (23/25) produced between 156 mM ± 11 and 330 mM ± 14 3-HPA, from 600 mM of glycerol, in the conditions of the test. All 25 poultry strains were sensitive to cefotaxime (MIC between 0.016 and 1 μg/mL) and penicillin (MIC between 0.02 and 4 μg/mL). Akin to the reference strains DSM20016 and SD2112, the novel isolates were resistant to penicillin, possibly associated with identified point mutations in ponA, pbpX, pbpF and pbpB. All strains resistant to erythromycin (4/27) carried the ermB gene, and it was only present in poultry strains. All strains resistant to tetracycline (5/27) harbored tetW gene. This study confirms the evolutionary history of poultry/human lineage VI and identifies pdu-cob-cbi-hem as a frequent trait but not always present in this lineage. L. reuteri poultry strains producing high 3-HPA yield may have potential to prevent enteropathogen colonization of poultry.

133. The Changing Phenotypes and Genotypes of Invasive Pneumococcal Isolates From Children in Shenzhen During 2013–2017

Background The phenotypes and genotypes of Streptococcus pneumoniae (Spn.) isolated from children with invasive pneumococcal diseases (IPDs) were changed in these years. The purpose of this study was to monitor this mutation trends before the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) in China. Methods Strains were isolated from children less than 14 years old between January 2013 and May 2017 in Shenzhen Children’s Hospital. Serotypes, antibiotic resistance, and genotypes of these isolates were determined using capsular swelling, E-test, and multi-locus sequence typing, respectively. Results A total of 94 Spn. strains were isolated, which belonged to 15 serotypes. The five most prevalent serotypes were 19F (25.5%), 19A (19%), 14 (17%), 23F (7.5%), and 6B (9.6%). The other two serotypes (19C and 15) were non-vaccine types. We found 42 sequence types (STs) for these isolates. The most abundant STs were ST271 (24.4%), ST876 (17%), and ST320 (10.6%), mainly related to 19F, 14, and 19A, respectively. The potential coverage of PCV13 was 87.2%. Among non-meningitis isolates, the resistance rates to penicillin and ceftriaxone were 0% and 2%. However, the meningitis isolates showed universal resistance to penicillin (80%) and ceftriaxone (20%). Most of these isolates (95.7%) were resistant to erythromycin, and 66 (70.2%) strains carried the ermB gene and 24 (25.5%) strains carried both the ermB and mefA/E genes. Serotype 19A showed the highest minimum inhibitory concentration (MIC) for penicillin than the other serotypes, but no significant difference in penicillin MIC among the three main STs (ST271, ST320, and ST876). Conclusion The phenotypes and genotypes of invasive pneumococcal isolates from children in Shenzhen have changed with the passage of time. Compared with PCV7, PCV13 can more effectively protect Chinese children from IPDs. To some extent, these changes are possibly related to the usage of antibiotics and vaccines. Disclosures All authors: No reported disclosures.