Inducible Clindamycin Resistance Research Articles

ANTIBIOTIC RESISTANCE PATTERN OF BACTERIAL PATHOGENS ISOLATED FROM PUS IN A TERTIARY CARE HOSPITAL OF CENTRAL INDIA

Pyogenic infections are commonly caused by various microorganisms and mixed infections that require antibiotic therapy. Emergence of antimicrobial drug resistance among susceptible individuals due to injudicious use of antibiotics has made the treatment of wound infections very difcult. This study was undertaken to determine the antibiotic resistance pattern among aerobic bacteria isolated from pus samples. A total of 312 pus samples were received in the Department of Microbiology, GMCH Nagpur from January to March 2021. The pus isolates were identied and processed by standard bacteriological techniques. The Antimicrobial Susceptibility Testing (AST) was performed by Kirby-Bauer disc diffusion technique and the drugs used were in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines 2020.Out of total 312 pus samples, 182 (58.33%) yielded signicant bacterial growth. The most prevalent pathogen isolated were Klebsiella pneumoniae 60 (19.23%) followed by Escherichia coli 42 (13.46%). Further, the study shows that Methicillin Resistant Staphylococcus Aureus (MRSA) and Inducible Clindamycin Resistance (ICR) were 29.41% and 11.76% respectively; moreover 70% isolates were Multi Drug Resistant (MDR). Therefore, this study indicates the prevalence of resistance to different classes of antibiotics in bacterial isolates and highlights the need for effective surveillance, regular reporting and antibiogram-guided antibiotic prescription.

Bacterial Profile and Antibiogram of Pathogens Causing Surgical Site Infections at Mnazi Mmoja Hospital in Zanzibar, Tanzania

A hospital based cross sectional study was done to determine bacterial profile and antibiogram of pathogens causing surgical site infections at Mnazi Mmoja Hospital in Zanzibar, Tanzania. The study was conducted from May to July 2017. We enrolled a total of 121 patients who underwent different surgical procedures and met study inclusion criteria. Pus swabs were collected and cultured as per standard operating procedures. Bacterial identification was then performed using biochemical tests and Analytical Profile Index test for Enterobacteriaceae (API 20E). Antimicrobial drug susceptibility testing was performed using Kirby Bauer disc diffusion technique. Data were analyzed using Statistical Package for Social Sciences (SPSS) version 21.0. Of 121 patients that were enrolled in the study, 75 (62%) developed surgical site infection (SSI). A total of 106 isolates were recovered from patients with positive culture results. The majority of the isolates, 92/106 (87%) were Gram-negative bacteria. The most predominant bacterium was Pseudomonas aeruginosa, 29/106 (27%) in all surgical Departments. Some of the isolated pathogens were multi-drug resistant (29/106; 27%), including Extended Spectrum Beta Lactamase (ESBL) producers (24/92; 26%), Methicillin Resistant Stahylococcus aureus (MRSA) (3/9; 33%) and Induced Clindamycin Resistance (ICR) strains (2/14; 14%). K. pneumoniae isolates showed the highest resistance towards most tested antibiotics (24.1-100%), and 24% of P. aeruginosa isolates were resistant to meropenem. In conclusion, P. aeruginosa was the most common isolated pathogen from patients with SSI in Zanzibar and the majority of the pathogens showed high resistance to commonly prescribed antimicrobial agents used in the hospital settings.

Staphylococcal scalded skin syndrome: Clinical features, ancillary testing, and patient management.

The utility of ancillary testing in improving diagnostic precision or improving patient outcomes in staphylococcal scalded skin syndrome (SSSS) is unclear. Similarly, an optimal antibiotic regimen has yet to be established. Our goal was to describe clinical characteristics and ancillary work-up of SSSS, report bacterial resistance patterns, and examine patient outcomes under varying therapeutic strategies with the aim of developing an evidence-based management algorithm. We performed a retrospective review of pediatric patients diagnosed with SSSS at Intermountain Healthcare facilities between 2010 and 2021. A Kruskal-Wallis rank sum test was used to assess median length of stay between different antibiotic regimens. Eighty-five cases were identified. The most common ancillary tests obtained were a complete blood count (88%), followed by chemistry analysis (80%). Blood cultures were collected in more patients (79%) compared to aerobic cultures (60%). No blood culture was positive for Staphylococcus aureus. All S. aureus isolates were methicillin-sensitive. Of those found resistant to clindamycin (36%), all demonstrated macrolide-induced clindamycin resistance. None were constitutively resistant to clindamycin. There was no statistical difference between antibiotic regimen and length of stay (p=.691). Receiving opiate medications was the only risk factor associated with prolonged hospitalization (p=.001). Ancillary testing does not improve diagnostic precision and can be reduced. Clindamycin does not improve patient outcomes, suggesting beta-lactams should be considered first line. Susceptibility patterns in our cohort demonstrate inducible clindamycin resistance as opposed to constitutive.

Prevalence and Clindamycin Resistance Profile of Staphylococcus aureus and Associated Factors among Patients Attending the University of Gondar Comprehensive Specialized Hospital, Gondar, Northwest Ethiopia.

Clindamycin can serve as an alternative treatment for staphylococcal infections. Routine susceptibility tests may fail to determine inducible type clindamycin resistance and can be a source of failure in clinical therapeutics. Therefore, this study aimed to determine Staphylococcus aureus (S. aureus) prevalence, inducible clindamycin resistance pattern, and associated factors among patients attending the University of Gondar Comprehensive Specialized Hospital, Gondar, northwest Ethiopia. Methods. A cross-sectional study was conducted from January to April 2018. Clinical samples were inoculated on appropriate culture media. Standard bacteriological tests, including Gram stain, catalase, and coagulase tests, identified the presence of S. aureus. The antimicrobial susceptibility tests and the D-test were performed by using the Kirby–Bauer disk diffusion technique on the Mueller–Hinton agar. The D-test was performed using clindamycin (CLI) 2 ug and erythromycin (ERY) 15 ug disks located approximately 15 mm apart, and the cefoxitin susceptibility test was used to characterize methicillin-resistant S. aureus (MRSA). The association between S. aureus infection and different variables was assessed using bivariate and multivariate analysis. A P value <0.05 was considered statistically significant. Result. Of 388 study participants, the overall prevalence of S. aureus was 17% (66/388). Of these, the inducible type of clindamycin resistance was 25.8% (17/66) and 21.2% (14/66) were MRSA. All isolates were susceptible to chloramphenicol and resistant to tetracycline. A family size of 4–6 (AOR = 2.627, 95% CI (1.030–6.702)) and >7 (AOR = 3.892, 95% CI (1.169–12.959)), inpatient study participants (AOR = 3.198, 95% CI (1.197–8.070)), illness in the previous 4 weeks (AOR = 2.116, 95% CI (1.080–4.145)), and a history of chronic disease (AOR = 0.265, 95% CI (0.094–0.750)) were likely to have S. aureus infection. Conclusion. This study shows a considerable high magnitude of MRSA and inducible clindamycin resistance S. aureus isolates. To rule out clindamycin susceptibility testing, the D-test should be routinely performed.

CHARACTERIZATION OF STAPHYLOCOCCUS AUREUS ISOLATED FROM BURN WOUND; STRONG ANTIBACTERIAL ACTIVITY OF PHAGE COCKTAIL AGAINST VANCOMYCIN INTERMEDIATE-RESISTANT STAPHYLOCOCCUS AUREUS

A universal problem is about spread of Staphylococcus aureus infections in burn patients. The present study aimed to learn about the molecular characteristics and the resistance pattern of S. aureus strains isolated from burn patients. In this cross-sectional study, we investigated 100 unique S. aureus isolated from burn patients by antimicrobial activity and biofilm formation and evaluated the effect of Complex Pyobacteriophage, a commercial bacteriophage cocktail, against the isolates mentioned above. Methicillin-resistant Staphylococcus aureus (MRSA) comprised 76%, and methicillin-susceptible Staphylococcus aureus (MSSA) comprised 24% of 100 S. aureus strains. The resistance rate among MRSA isolates was higher than compared of MSSA. Mupirocin resistance was found in 30% of isolates, with 28 (93.3%) and 2 (6.7%) strains of MRSA and MSSA, respectively, found. Vancomycin intermediate resistance in S. aureus (VISA) was 13% of MRSA strains. Two isolates were confirmed as vancomycin-resistant S. aureus (VRSA) strains and carried vanA. 31 and 62% of the total isolates showed inducible and constitutive resistance phenotypes. The rate of inducible and constitutive clindamycin resistance among MRSA strains was higher than MSSA strains. Biofilm production was detected in 66% of isolates. Strong, moderate, and weak producers accounted for 25%, 17%, and 24% of isolates. Phage analysis showed that 81% were susceptible to the phage cocktail, and only 19% were resistant to the phage cocktail. Our data indicated that VISA strains prevalence in the burn unit was mainly from S. aureus infections. Present work recommended that vancomycin treatment be closely monitored to prevent the spread of VISA and VRSA strains. Observations also highlighted the role of bacteriophage cocktails in eradicating S. aureus-related infections.

Inducible clindamycin resistance in coagulase negative staphylococci

Induced clindamycin resistance poses a major problem for the use of this drug to treat staphylococcal infections. An infectious etiology is often implicated in the presence of CoNS in clinical specimens. A total of 183 isolates of Staphylococci spp. recovered from different clinical specimens were studied. A coagulase test was done to select coagulase negative Staphylococci, and they were confirmed by conventional microbiological techniques. Using the double disc approximation test, induced clindamycin resistance was detected (D-test). The D test was used to detect the inducible clindamycin resistance phenotype in erythromycin resistant and clindamycin sensitive isolates. A micro titer plate test was used to determine biofilm development in these isolates. One hundred and twenty eight isolates from various clinical specimens were identified as proven CoNS, which were distributed across six different species’. haemolyticus, the most common species of CoNS isolated, was isolated from all types of specimens. The present study revealed the strong association of biofilm with inducible clindamycin resistance among the CoNs isolates.

Inducible Clindamycin-Resistant Staphylococcus aureus Strains in Africa: A Systematic Review.

Introduction Excessive use of clindamycin enhances the acquisition of inducible clindamycin-resistant S. aureus strains, which is a significant health problem in Africa. The main objective of this review study was to determine the prevalence of inducible clindamycin resistance and related genes among S. aureus isolates in Africa. Methods A qualitative systematic review was conducted on inducible clindamycin resistance among S. aureus isolates in Africa using electronic databases such as Google Scholar and PubMed. Articles published in English before 2021 were selected, and relevant data were extracted, collected, and analyzed. Results In our search, 22 articles met the eligibility criteria for this review study. Of 3064 total S. aureus isolates, 605 had iMLSB phenotype. The overall prevalence of inducible clindamycin resistance in S. aureus isolates was 19.8% with a range of 2.9% to 44.0%. A high number of iMLSB phenotypes were observed in MRSA isolates (3.6–77.8%) than MSSA (0–58.8%). The overall prevalence of the iMLSB phenotype in MRSA strains was 26.8% (279/1041). The maximum peak prevalence of inducible clindamycin resistance among S. aureus isolates recorded in the continent was 44.0% in Egypt, followed by 35.8% in Libya and 33.3% in Uganda in 2017, 2007, and 2013, respectively. The highest prevalence of iMLSB phenotype in MRSA strains was reported in Egypt, 77.8%, followed by Nigeria, 75.0%, and Libya, 66.2%. Among the recovered drug-resistance genes, ermA, ermC, and msrA genes were commonly detected in Egypt with 67.9%, 70.0%, and 70.0% prevalence, respectively. Conclusion This review highlights a higher inducible resistance of S. aureus, including MRSA strains to clindamycin in the continent. Regular screening of these strains, wise use of clindamycin, and molecular detection and genotyping of resistant genes are urgent.

Detection and Prevalence of Inducible Clindamycin Resistance in Clinical Isolates of Staphylococcus aureus: Experience from Tertiary Care Hospital in Jaipur

Background: Staphylococcus aureus is a frequent cause of bacterial infections in both developed and developing countries. Emerging resistance to methicillin in this organism has left us with very few therapeutic alternatives to treat the infections caused by them. Objective: We aimed to determine the prevalence of inducible clindamycin resistance in clinical isolates of S. aureus and antimicrobial susceptibility pattern of S. aureus isolates due to the increasing prevalence of resistance to most antimicrobial agents in staphylococci signifies the need for new effective agents to treat staphylococcal infections. Methods: The study was carried out in the Department of Microbiology at Mahatma Gandhi Hospital, Sitapura, Jaipur, Rajasthan. All S. aureus isolates (non-repetitive) from different clinical samples received in clinical microbiology laboratory from in and outpatients in Mahatma Gandhi Medical College and Hospital, Jaipur, Rajasthan, were included in the study. Results: Out of 157 erythromycin-resistant S. aureus, 74 (47.133%) show MS phenotype, 48 (30.57%) show inducible clindamycin resistance, and 35 (22.29%) show constitutive resistance. All 48 S. aureus isolates which showed inducible clindamycin resistances (D-test positive) were further subjected to antimicrobial susceptibility testing.In the present study, 100% sensitivity was observed by vancomycin, linezolid and tigecycline, followed by tetracycline, 89.58% and gentamicin, 83.33% while 100% resistivity were observed by levofloxacin. Conclusion: We can conclude that there is high percentage of inducible clindamycin resistance among Staphylococcus isolates. If D-test would not have been performed, many inducible clindamycin-resistant S. aureus could have been easily misidentified as clindamycin susceptible, leading to therapeutic failure. Thus, simple and reliable D-test can be incorporated into routine in clinical microbiology laboratory.

Clinico-bacteriological profile and antibiogram of Staphylococcus epidermidis with special emphasis on Methicillin resistance and hospital acquired infections in a tertiary care center south India

is a normal commensal of the skin and mucous membrane of humans and animals. Despite the growing importance of its pathogenesis especially in neonatal septicemia and device associated infections, it is still considered as insignificant isolate in the clinical practice. Hence, the present study is taken up to analyze the sources and risk factors of the isolates and to know their antibiogram along with occurrence of Methicillin resistant (MRSE).150 clinically significant isolates from various clinical specimens were considered in this study. Species identification was done by phenotypic methods. The antimicrobial susceptibility test and detection of Methicillin resistance were performed by Kirby-Bauer's disc diffusion method as per CLSI guidelines.Among 150 isolates, 78% were recovered from hospital acquired infections. They were commonly isolated in pediatric age group (30%) and among males (60.67%). Total of 34.67% were isolated from pus samples followed by blood (25.33%). Most of the isolates were associated with multiple risk factors like hospitalization, prior antibiotic administration, foreign body in situ and ICU admission. Majority of the isolates expressed resistance towards Penicillin (93.33%), followed by Amoxicillin-Clavulanic acid (76%), Cotrimoxazole (71.33%), Fluoroquinolones (64%), Gentamicin (60%) and Erythromycin (55.33%). Resistance against Amikacin (16.67%), Tetracycline (9.3%) and Linezolid (0.67%) was low. All isolates were sensitive to Vancomycin. Inducible Clindamycin resistance was 18% and MRSE was 68%.: Clinical importance and emergence of drug resistance among infections is growing with the advent of advanced medicine. This warrants the need to implement simple laboratory methods for species identification of the and to determine the antibiotic resistant patterns on routine basis. Clinical correlation of the isolate is crucial to rule out the colonizers and contaminants.

Bacteriological profile and antibiogram analysis from a tertiary care centre in eastern India: Time to Act / ReAct

Development of antimicrobial resistance imposes a serious threat to the timely and efficient healing of mankind who fall prey to the infectious agents. It is increasingly being reported day by day throughout the world. Irrational and overuse of antibiotics coupled with unavailability of regional or local antibiogram aggravates the situation further.To understand and present the local antbiogram data for this region and bridge the existing knowledge gap about the same for this particular region.Two year data was retrospectively analyzed from a 750 bedded tertiary care centre.A total of 1143 non repeat isolates were studied, their antibiogram profiles were analyzed. Percentage of Gram negative bacteria obtained were 59.6%, while Gram Positive bacteria were obtained in 40.4% of the isolates. (22.8%) was the most common organism isolated, followed by Staphylococcus aureus (14.2%), Other sp(12.8%), sp(12.6%), (9.4%), and complex(7.4%), Miscellaneous Bacteria(13.4%). An alarming number of isolates were found to be Multidrug resistant isolates(MDRs). With the panel of antibiotics tested for Gram negative bacterial isolates, only Fosfomycin(1.5%), Nitrofurantoin(16%) &amp; Chloramphenicol (19%) were the only antibiotics to exhibit &amp;#60;20% resistance. Antibiotics for Gram positive bacteria for which low resistance was observed were Vancomycin (0%), Linezolid (0.1%), Teicoplanin (&amp;#60;1%), Aminoglycosides (18%), Nitrofurantoin(15%), Chloramphenicol(6%) &amp; Tetracyclines(11%). Extended Spectrum Beta lactamase(ESBL) prevalence was estimated to be 63.6% in , 82.4% in Klebsiellapneumoniae. Methicillin resistant Staphylococcus aureus (MRSA) was seen in 54% of the isolates, while Inducible clindamycin resistance was observed in 35.9% of the isolates.It is high time that we shift our focus from internationally and nationally available data on antibiogram to locally prevalent antibiotic resistance pattern. It will ensure faster patient recovery at a lesser cost and also prevent undue development of drug resistance.

Constitutive and Inducible Clindamycin Resistance Frequencies among Staphylococcus sp. Coagulase Negative Isolates in Al-Basrah Governorate, Iraq.

Antibiotics called macrolide, lincosamide and streptogramin B (MLSB) are being used to treat staphylococci infections. Multiple pathways that impart resistance to MLSB antibiotics have been confirmed to cause clinical failure. The present work aimed to determine the frequency of constitutive and inducible clindamycin resistant among coagulase-negative staphylococci (CoNS) isolates of different clinical samples in Al-Basrah governorate, Iraq. The 28 CoNS, traditional techniques and the Vitek®2 system were used to identify the isolates. The disk diffusion technique was used to detect methicillin resistance and antibiotic sensitivity patterns via cefoxitin, gentamicin, ciprofloxacin, amikacin, teicoplanin, linezolid, doxycycline and vancomycin disks. Erythromycin and clindamycin antibiotic disks was used to detect the inducible and constitutive clindamycin resistance as well as a D-test according to CLSI guidelines. Among 28 CoNS isolated, the Staphylococcus aureus 11(39.29%), Staphylococcus epidermidis 7(25 %), Staphylococcus haemolyticus 4(14.29%) and Staphylococcus saprophyticus 3 (10.71%) were predominant isolated species. Out of 28 CoNS isolates, 15(53.57%) were methicillin resistant coagulase-negative staphylococci (MRCoNS) isolates and 13(46.43%) were methicillin sensitive coagulase-negative staphylococci (MSCoNS) isolates. The 15(53.57%) isolates out of 28 CoNS, showed erythromycin resistance while 6(40%) isolates out of 15 CoNS, showed inducible macrolide-lincosamide-streptogramin B (iMLSB) and 2(13.3%) of CONS isolated showed constitutive macrolide-lincosamide-streptogramin B (cMLSB). In order to achive the best result in choosing the suitable treatment and avoiding the loses the money and time, it is better to use the D-test for inducible clindamycin resistance in the daily routine work of antibiotic susceptibility testing in hospital and private clinical laboratories.

Four year trend of antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus in a tertiary care hospital, Lahore.

To determine the susceptibility pattern of methicillin-resistant staphylococcus aureus to different antibiotics. The descriptive study was conducted at the Microbiology Department of the University of Health Sciences, Lahore, Pakistan, from August 2016 to July 2019, and comprised staphylococcus aureus samples that were processed and identified using colony morphology on blood agar, gram stain, catalase, coagulase and deoxyribonuclease testing. Screening for methicillin-resistant staphylococcus aureus was done using cefoxitin disc 30µg and oxacillin disc 1mg. Antimicrobial susceptibility was tested using the modified Kirby-Bauer disc diffusion method in line with the Clinical and Laboratory Standards Institute guidelines 2019. Data was analysed using SPSS 24. Of the 2704 strains processed, 402(14.86%) were found to be methicillin-resistant staphylococcus aureus. Of them, 204(50.74%) were recovered from pus, while 10(2.48%) were recovered from urine. All 402(100%) isolates were sensitive to vancomycin and linezolid, and resistant to penicillin, followed by erythromycin 306(76.11%) and sulfamethoxazole/ trimethoprim 295(73.38%). Overall, lower resistance was seen with doxycycline 145(36.06%) and clindamycin 160(39.80%). Inducible clindamycin resistance was seen in 142(35.23%) isolates. An efficacious susceptibility pattern of methicillin-resistant staphylococcus aureus was seen with vancomycin and linezolid, moderate susceptibility with doxycycline and clindamycin, while high resistance was observed for penicillin, erythromycin and trimethoprim/sulfamethoxazole.

Comparison of Phenotypic and Genotypic Characterization Methods for the Detection of Methicillin-Resistant Staphylococcus Aureus.

IntroductionMethicillin-resistant Staphylococcus aureus (MRSA) is associated with high morbidity and mortality due to the development of antimicrobial resistance secondary to irrational use of antibiotics, nonadherence to infection control practices, and increased use of intravascular devices in healthcare systems. Detection of MRSA is critical in clinical microbiology laboratories as it helps identify MRSA carriers and avoid treatment failure in patients. Hence, this study compared various phenotypic methods with the standard genotyping method to determine a method that permits rapid and accurate detection of MRSA.Materials & MethodsStaphylococcus aureus (S. aureus) was initially identified based on colony morphology, Gram staining, standard biochemical tests, and antibiotic susceptibility using disk diffusion. MRSA was identified based on the detection of the mecA gene by polymerase chain reaction (PCR) and subsequent gel electrophoresis. Disk diffusion using cefoxitin or oxacillin and mannitol salt agar with 6-µg/ml oxacillin were used for phenotypic detection of MRSA. The D test was used to detect inducible clindamycin resistance in S. aureus isolates.ResultsOf the 100 S. aureus isolates analyzed, 37% were identified as MRSA by PCR and the cefoxitin disk diffusion method; however, only 31% were detected by the oxacillin disk diffusion method and 29% by the mannitol salt agar method. The sensitivity of the cefoxitin disk diffusion test, oxacillin disk diffusion, and mannitol salt agar methods was 86.05%, 83.78%, and 70.73%, respectively. Specificity was 100% for all the three phenotypic methods (p < 0.001). Notably, inducible clindamycin resistance was found in 37.2% of the MRSA isolates, indicating potential challenges in treatment.ConclusionAmong the three phenotypic methods tested, the cefoxitin disk diffusion method had 100% sensitivity and specificity, which is similar to that of PCR-based MRSA detection. Hence, the cefoxitin disk diffusion method is recommended for use in clinical laboratories, where molecular methods are not available as it is both cost-effective and easy to perform.

MecA and ermA Gene Discrepancy from Their Phenotypic Profile in Staphylococcus aureus Isolates

Objectives: Staphylococcus aureus is one of the most important bacterial pathogens in clinical practice and a primary diagnostic focus for the routine microbiology laboratory. The aim of this study was to find out the phenotypic and genotypic variations in Staphylococcus aureus isolates at a tertiary care center in Lucknow. Methods: 140 clinical isolates of S. aureus were taken in the study. Kirby–Bauer disc diffusion method was performed to identify antibiotic susceptibility testing, phenotypically methicillin-resistant Staphylococcus aureus (MRSA) were identified by using cefoxitin disc (30 μg), and inducible clindamycin resistance was identified by the presence of D-shaped zone around clindamycin and by using conventional PCR method mecA and ermA genes were identified. Results: Out of 140 clinical isolates S. aureus, 93 (66.4%) were MRSA, and 47 (33.6%) were methicillin-sensitive Staphylococcus aureus (MSSA). Phenotype iMLSb was 41 (29.3%), cMLSb phenotype was 37 (26.4%), mecA gene was present in 84 (60%), and none of the samples showed ermA gene positivity. Conclusion: As we know, the presence of the mecA gene is the major evidence for the detection of MRSA isolates. Their presence in low numbers opens the door to search for other mechanisms that may compete with mecA gene in producing resistance phenomenon. The absence of ermA gene in strains S. aureus with iMLSb and cMLSb phenotypes concluded that some other erm gene is responsible for this MLS type of resistance. Due to the frequency of MRSA strains showing the iMLSb phenotype, the use of clindamycin in erythromycin-resistant strains cannot be recommended due to the high possibility of failure in treatment with this antibiotic. J Microbiol Infect Dis 2021; 11(4):6-11.

Bacterial profile, antimicrobial susceptibility patterns, and associated factors of community-acquired pneumonia among adult patients in Gondar, Northwest Ethiopia: A cross-sectional study.

IntroductionCommunity-acquired pneumonia is associated with higher morbidity, hospitalization, and mortality in adults. Likewise, antimicrobial resistance has increased in recent decades in Ethiopia. Therefore, this study was aimed to determine the bacterial isolates, their antimicrobial susceptibility patterns, and factors associated with community-acquired pneumonia among adult patients in Gondar, Northwest Ethiopia.Materials and methodsThis institutional-based cross-sectional study was conducted from April to June 2021. Sociodemographic, clinical, and other relevant data were collected using a pre-tested questionnaire. A total of 312 sputum specimens were collected using sputum cups and inoculated into blood agar, chocolate agar, mannitol salt agar, and MacConkey agar plates, which were then incubated at 37°C for 24 hours. The bacterial isolates were identified based on Gram staining, colony characteristics, and biochemical tests. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Inducible clindamycin resistance among the S. aureus isolates was detected by the D-test. Data were entered using EPI data version 4.6 and analyzed using SPSS version 20. P-value ≤ 0.05 at 95% CI was considered statistically significant.ResultsOf 312 cases, 39.4% (n = 123; 95% CI: 34.1%–44.9%) were found to have culture-confirmed pneumonia. The most common isolates were K. pneumoniae (31.0%, n = 39), S. pneumoniae (26.2%, n = 33), and S. aureus (20.6%, n = 26). The gram-positive bacteria were susceptible to chloramphenicol (100%) and clindamycin (96.6%). Gram-negative bacteria were susceptible to gentamicin (87.5%), azithromycin (87.1%), ciprofloxacin (86.6%), and ceftriaxone (79.0%) but highly resistant to ampicillin (100%), followed by tetracycline (87.1%), doxycycline (86.4%), co-trimoxazole (80.6%), and amoxicillin-clavulanic acid (79.0%). Overall, 72.2% of the isolates were multi-drug resistant to K. pneumoniae (94.9%, n = 37), E. coli (93.8%, n = 15), and S. pneumoniae (72.7%, n = 24). Only, 7.7% of S. aureus isolates showed inducible clindamycin resistance. Aging (AOR: 3.248, 95% CI: 1.001–10.545, p = 0.050), a history of pneumonia (AOR: 7.004, 95% CI: 3.591–13.658, p = 0.001), alcohol use (AOR: 6.614, 95% CI: 3.399–12.872, p < 0.001), and overcrowded living conditions (AOR: 4.348, 95% CI: 1.964–9.624, p = 0.001) were significantly associated with culture-positive sputum.Conclusion and recommendationsThis study found a high prevalence of bacteria-caused community-acquired pneumonia among adults and low susceptibility to ampicillin, tetracyclines, and amoxicillin-clavulanic acid. Therefore, culture-based bacterial identification and local antibiotic susceptibility testing should be performed regularly. Additionally, new insights into vaccine coverage against highly multi-drug resistant bacteria, particularly K. pneumoniae, are necessary.

Epidemiology, Microbiological Characteristics and Clinical Outcomes of Invasive Blood Stream Infections of Group B Streptococcal Isolates From Qatar

Background: Group B Streptococci (GBS) or Streptococcus agalactiae colonize humans genitourinary and gastrointestinal tracts particularly in females1. The pathogen is capable of causing invasive disease primarily in infants, pregnant and postpartum women as well as the elderly and patients with comorbidities2. There is a paucity of studies on the disease with regional differences in prevalence and presentation of invasive bloodstream infection (BSI)3. In this study, we aim to assess the prevalence, microbiological characteristics as well as clinical outcomes of invasive GBS disease from all ages groups at Hamad Medical Corporation (HMC), Qatar. Methods: A retrospective study was conducted on all patients with microbiologically confirmed GBS bacteremia between January 2015–March 2019. Demographic, microbiological characteristics, as well as clinical data, were extracted from the hospital information system. Results: Out of the 196 confirmed cases of GBS bloodstream infections, 63.7 % were females (125/196) of whom 44.8 % were pregnant (56/125). There were three distinct age group populations: pediatric less than 4 years of age at 35.7 %, young adults 25-34 (20.9 %), and the elderly &gt; 65 years (17.4 %). Presenting symptoms were fever in 53 % of the cases (104/196) (Table 1). Microbiological characteristics using disc diffusion tests demonstrated all isolates were universally sensitive to penicillin (100%, 196/196) with significant resistance to clindamycin at 28.6 % (56/196) and erythromycin at 49 % (96/196) of which 34.4 % (33/96) had inducible clindamycin resistance (Figure 1). The clinical outcomes showed a high cure rate of 87.25% (171/196) with low complications at 8.76 % (17/196) and 4% (8/196) 30-day mortality. Conclusion: Streptococcus agalactiae bloodstream infection in Qatar is common in females, affects the very young, and the elderly. The organism remains universality sensitive to penicillin with significant resistance to clindamycin and erythromycin. Patients present with mild symptoms have high cure rates, low complications, and safe outcomes for the majority of cases.

Determination of Inducible Clindamycin Resistance Amongst Clinical Isolates of Methicillin-Resistant Staphylococcus aureus in Kaduna, Nigeria

For quite a long time, mainly due to fewer treatment options, Clindamycin have been regarded as an alternative drug to effectively manage all Staphylococcus aureus infections. Strains with inducible clindamycin resistance (iMLSB phenotype) raise concerns because therapeutic failure may occur during treatment. Clindamycin is mostly regarded in treating serious infections that cannot be treated by other antibiotics, as it may cause colitis or mild diarrhea. A double disc diffusion test (D-test) for detecting inducible resistance to clindamycin in erythromycin-resistant methicillin-resistant S. aureus was performed by placing a 15µg erythromycin disc in proximity to a 2µg clindamycin disc in adjacent positions. For erythromycin-resistant isolates, D-test can help to determine whether clindamycin could be used as a therapeutic option (reported as susceptible when the D-test is negative or reported as resistant when the D-test is positive). Twenty (20) out of the 30 (thirty) isolates collected were confirmed to be determined by D-test as per CLSI guidelines. Fifteen (15) isolates were D-test Negative, 5 were resistant to both Erythromycin and Clindamycin, and none was D-test positive. D-test should be included as a mandatory method in routine disc diffusion testing to detect inducible clindamycin resistance in staphylococci for the optimum treatment of patients.

Biofilm Formation in Methicillin-Resistant and Methicillin-Sensitive Staphylococcus aureus Strains

Background: The combination of methicillin resistance (MR) and the ability of biofilm formation of Staphylococcus aureus (SA) makes treatment difficult. Biofilm is formed by distinct genetic mechanisms in MRSA and methicillin-sensitive SA (MSSA), and hence, there is difference in the prevalence of biofilms in them. This study investigated the biofilm production in SA and analyzed its correlation with MR. Materials and methods: A total of 261 consecutive Staphylococcus aureus isolated from various clinical samples from January to April 2019 were included in the study. Antibiotic sensitivity was carried out as per Clinical and Laboratory Standards Institute guidelines and cefoxitin disk was used for screening for MR. Total of 147 MSSA and 114 MRSA were taken for further processing. Biofilm formation was determined by tube and microtiter plate methods in all the isolates. The data were analyzed for statistical significance using Microsoft excel software. Results: Resistance to erythromycin, clindamycin, gentamicin, cotrimoxazole, and inducible clindamycin resistance was significantly higher in all the MR Staphylococcus strain including biofilm forming MRSA strains. The biofilm formation was significantly higher in MSSA isolates by both the tube (78.2%) and microtiter plate methods (64.9%). Discussion: Although the antimicrobial resistance was higher in MRSA, the ability to form biofilms was significantly higher in MSSA. Biofilms of MSSA are usually less prevalent than MRSA probably because of the distinct genetic mechanisms involved in the formation of biofilms. The higher biofilm forming ability of MSSA in our study highlights the need for determination of other genes involved in biofilm formation and virulence mechanisms in SA.

Inducible Clindamycin Resistance and Biofilm Production among Staphylococci Isolated from Tertiary Care Hospitals in Nepal.

Resistance to antibiotics, biofilm formation and the presence of virulence factors play important roles in increased mortality associated with infection by staphylococci. The macrolide lincosamide streptogramin B (MLSB) family of antibiotics is commonly used to treat infections by methicillin-resistant isolates. Clinical failure of clindamycin therapy has been reported due to multiple mechanisms that confer resistance to MLSB. This study aims to find the incidence of different phenotypes of MLSB resistance and biofilm production among staphylococci. A total of 375 staphylococci were isolated from different clinical samples, received from two tertiary care hospitals in Nepal. Methicillin resistance was detected by cefoxitin disc diffusion method and inducible clindamycin resistance by D test, according to CLSI guidelines. Biofilm formation was detected by the tissue culture plate method and PCR was used to detect ica genes. Of the total staphylococci isolates, 161 (42.9%) were Staphylococcus aureus, with 131 (81.4%) methicillin-resistant strains, and 214 (57.1%) isolates were coagulase-negative staphylococci, with 143 (66.8%) methicillin-resistant strains. The overall prevalence of constitutive MLSB (cMLSB) and inducible MLSB (iMLSB) phenotypes was 77 (20.5%) and 87 (23.2%), respectively. Both iMLSB and cMLSB phenotypes predominated in methicillin-resistant isolates. The tissue culture plate method detected biofilm formation in 174 (46.4%) isolates and ica genes in 86 (22.9%) isolates. Among biofilm producing isolates, cMLSB and iMLSB phenotypes were 35 (20.1%) and 27 (15.5%), respectively. The cMLSB and iMLSB were 11 (12.8%) and 19 (22.1%), respectively, in isolates possessing ica genes. Clindamycin resistance in the form of cMLSB and iMLSB, especially among MRSA, emphasizes the need for routine D tests to be performed in the lab.

184. Inducible Clindamycin Resistance Testing on Pediatric Streptococcus pneumoniae Isolates

BackgroundIn 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.MethodsWe 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.ResultsWe 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). ConclusionErythromycin-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)