Inducible Clindamycin Resistance Research Articles

Prevalence and genetic characteristics ofStaphylococcus aureus isolates from cellphones of medical students from Iran.

Although mobile phones as a rapid communication vehicle can lead to improved quality of healthcare, they can also facilitate the transmission of pathogens to patients. This current research focuses on genetic diversity, and genes involved in resistance and biofilm production of Staphylococcus aureus isolates from mobile phones of medical students. Antibiotic resistance profiling and polymerase chain reaction (PCR) amplification of antibiotic resistance and biofilm-related genes were investigated and statistically analyzed. Staphylococcal cassette chromosome mec (SCCmec) types were analyzed by multiplex PCR, and S. aureus protein A gene typing (spa typing) was done using PCR and sequencing. Sixty-four S. aureus isolates (16.8%) were obtained from 380 medical students' mobile phones who were working in hospitals. The findings showed that 71.9% of the isolates were MRSA and 78.1% were classified as MDR. All isolates exhibited sensitivity to vancomycin and linezolid. Overall, 7.8% of the isolates displayed an inducible clindamycin resistance phenotype, while 26.7% showed resistance to mupirocin. The results indicated that 68.8% of the isolates were biofilm producers, with 7 isolates (15.9%) classified as strong producers, 22 isolates (50%) as moderate producers, and 15 isolates (34.1%) as weak producers. The most prevalent type was CC8-MRSA III/t030 (18.7%), followed by CC8-MRSA III/t037 (12.5%), CC/ST22-MSSA/t790 (10.9%), CC1-MRSA IV-t114 (9.4%), CC1-MRSA IV-t127 (7.8%), CC8-MRSA V/t064 (7.8%), CC/ST15-MSSA-t360 (7.8%), CC30-MSSA/t021(6.3%), MRSA V-t355 (6.3%), CC8-MRSA III/t421 (4.7%), CC1-MRSA V-t267 (4.7%), and CC/ST15-MSSA-t084 (3.1%). The genetic diversity and prevalent multidrug resistance indicate that the resistance situation of S. aureus recovered from mobile phones in Tehran is severe, posing a potential threat to patients, the community, and healthcare settings.

Detection of Multidrug Resistant <i>Staphylococcus aureus </i>at Morogoro Regional Referral Hospital, Tanzania

<i>Background: </i>Hospital settings are associated with constant introduction of pathogens which can be transmitted among workers by patients, and visitors, resulting into potential nosocomial infections. This study compared the carriage and pattern of drug resistant <i>S. aureus </i>among patients and on equipment in hospital setting at Morogoro Regional Referral Hospital (MRRH). <i>Methods:</i> A cross sectional study was conducted by collecting samples from the anterior nares using sterile cotton swabs from patients. Furthermore samples were collected from inanimate surfaces, ward door handles; wheelchairs; and trolleys. The samples were incubated on mannitol salt agar plates aerobically at 37°C for 24 hours. Antimicrobial susceptibility testing was done using; erythromycin, azithromycin, ofloxacin, gentamicin, ciprofloxacin and cefoxitin. Clindamycin inducible resistance was tested by D test as per CLSI (2019). Data analysis was carried using SPSS where Chi – square was used to compare the association of occurrence of resistance and source of isolation. <i>Results: </i>Out of 200 samples, 54 tested positive for <i>S. aureus </i>were from human while the prevalence of <i>S. aureus </i>in inanimate objects was high in beds 10 (40%). The AMR was observed more in azithromycin (26.3%) than other antimicrobials. The D-Test showed inducible clindamycin-resistant phenotype in 57.1% of the MRSA isolates. The maternity ward had the highest risk of being exposed to <i>S. aureus </i>contamination [OR = 9.9 (95% CI, 2.0-19.30), p = 0.01] and tables [OR = 4.6 (95% CI, 1.22-1.89, p= 0.03)]. The recovery wards were least likely to be contaminated with the result of four times likely to be contaminate for both patients and surfaces [OR = 5.1 (95% CI, 1.3-8.6), p= 0.04] when compared with other wards. <i>Conclusion: </i>This study presents some important findings on MRSA which is a global concern, the authors encourages more researches are done in MRSA for efficient availability in the AMR database.

Trends of Antibacterial Interactions in Multidrug – Resistant Isolates: Exploring Resistance Phenotypes in the Ndé Division, West-Cameroon

Background: Reliable pieces of information concerning bacterial-antibiotic interactions are key assets for therapeutic management of bacterial diseases.
 Objective: The present study aimed at detecting phenotypic characteristics of bacterial resistance in multidrug-resistant isolates recovered from clinical specimens at the “Université des Montagnes” Teaching Hospital.
 Methods: The total of 226 isolates (142 Gram-negative rods and 84 Gram-positive cocci) were subjected to phenotypic screening of resistance mechanisms. All procedural steps were conducted according to standard protocols on bacterial susceptibility to antibiotics.
 Results: Primary pieces of information revealed high rates of resistant isolates, especially with beta-lactams and Trimethoprim/Sulfamethoxazole while Nitrofurantoin and Imipenem were most effective. Amongst Gram-negative rods, 56% expressed one enzymatic resistance mechanism and 12% expressed two against beta-lactams. Also, with extended spectrum beta-lactamases, high level cephalosporinases and inducible cephalosporinases most commonly observed. About 62% and 14% of Gram-positive cocci expressed constitutive and Clindamycin-inducible resistance, respectively. Decreased susceptibility to Ceftriaxone and Penicillin G was also recorded in suspect mutant isolates selected by these antibiotics. Potential synergetic and other antagonistic interactions were evenly detected.
 Conclusion: Overall, the data could represent reliable clue for advocacy about personalized combination therapy, then capacity building for routine affordable susceptibility tests in caretaking.

Prevalence of inducible clindamycin resistance amongst methicillin resistant and sensitive strains of Staphylococcus aureus from a tertiary care hospital, West Bengal, India.

Background: Staphylococcus aureus is a prevalent pathogen causing both nosocomial and community-acquired infections worldwide. The emergence of methicillin-resistant Staphylococcus aureus (MRSA) due to the acquisition of mecA and mecC genes poses a significant clinical challenge. The injudicious use of clindamycin for treating MRSA has led to the development of clindamycin resistance. This study aimed to determine the prevalence of inducible clindamycin resistance (iMLSB resistance phenotype) in Staphylococcus aureus isolates, employing the D test according to CLSI guidelines, particularly focusing on erythromycin-resistant strains. Methodology: A total of 147 Staphylococcus aureus isolates were subjected to antibiotic susceptibility testing using the Kirby Bauer disc diffusion method. The D test was employed to identify inducible clindamycin resistance. Results: The study revealed that 34% of isolates exhibited inducible clindamycin resistance, 40% demonstrated constitutive resistance, and the remaining 26% exhibited the MS phenotype. Notably, inducible clindamycin resistance was more prevalent in MRSA (40%) compared to MSSA (22%). Conclusion: The findings underscore the importance of incorporating the D test as a mandatory procedure in standard disc diffusion testing to accurately identify inducible clindamycin resistance. This knowledge is crucial for guiding appropriate antibiotic therapy in the face of increasing resistance patterns.

Determination of Inducible Clindamycin Resistance and Correlation with Vitek2 Inducible Clindamycin Resistance Test in Staphylococcus aureus Isolated from Clinical Samples.

To compare the performance of Vitek2 with the gold standard D test in terms of inducible clindamycin resistance (ICR) detection. Descriptive study. Place and Duration of the Study: Indus Hospital and Health Network Karachi, Pakistan, from November 2021 to April 2022. Standard operating procedures of the laboratory were followed for processing of clinical samples. Methicillin-resistant Staphylococcus aureus (MRSA) isolates were included. The isolates from the same patient within two-week time period were excluded. Clinical laboratory standards institute guidelines were followed for performing and interpreting D test. The results of the D test were compared with Vitek2 results for ICR. A total of 313 isolates were MRSA, of which 93 isolates tested positive for ICR on both the D test and Vitek2. Nine isolates were positive for ICR on Vitek2 and negative on the Kirby-Bauer disk diffusion method. One isolate tested positive on the disk method and negative on Vitek2. Vitek 2 appeared to give false positive results. Reporting false susceptibility of clindamycin can cause therapeutic failure which can markedly affect the patient's outcome. This discordance needs to be investigated further with a large sample size and stringent observation of D-test results to pick laboratory error. Methicillin-resistant Staphylococcus aureus, Inducible clindamycin resistance, D zone, Vitek2.

Clindamycin Resistance Detection among MRSA at a Tertiary Care Hospital: A Cross-sectional Study

Introduction: Antimicrobial resistance is on the rise, posing a global threat to the success of modern surgical procedures. A common and notorious superbug causing community and hospital-acquired infections is Methicillin-resistant Staphylococcus aureus (MRSA). Its potential for easy and rapid spread leads to increased mortality in hospitals. Clindamycin, a relatively inexpensive and effective drug, is empirically prescribed for the treatment of MRSA infections. Due to the risk of misidentifying clindamycin resistance as susceptibility, leading to treatment failure, its judicious use after D-test is advocated. Aim: To isolate Staphylococcus aureus (S.aureus) from various clinical specimens and to identify MRSA using cefoxitin disc (30 μg), further determining the incidence of inducible clindamycin resistance among MRSA by the disc diffusion method (D-test). Materials and Methods: The present cross-sectional study was conducted in the Department of Microbiology, Government Mohan Kumaramangalam Medical College Hospital (GMKMCH), Salem, Tamil Nadu, India, from June 2023 to August 2023. Study was conducted using 185 S.aureus isolates collected from samples received from patients of all genders treated at the present study hospital. Various clinical samples such as pus, sputum, blood, urine and fluids collected from patients treated at the study Institute Salem during the study period were included. A cefoxitin disc (30 μg) was used to detect MRSA among the 185 S.aureus isolates by disc diffusion method as per Clinical and Laboratory Standards Institute (CLSI) guidelines, which were further tested for clindamycin resistance using clindamycin (2 μg) with erythromycin (15 μg) discs by the D-test. The data of the study were analysed using Statistical Package for the Social Sciences (SPSS) software version 21.0. Further descriptive statistics and a chi-square test with a level of significance, p-value ≤0.005 (statistically significant), were used. Results: Among 185 S.aureus isolates, 130 (70.27%) were Methicillin-sensitive S.aureus (MSSA) and 55 (29.7%) were MRSA. Inducible clindamycin resistance was observed in 22 (40%) isolates, while 17 (30.9%) isolates showed constitutive resistance, 9 (16.36%) showed the MS phenotype, and the remaining 7 (12.72%) showed the susceptible phenotype. Among the clindamycin resistance patterns in MRSA, inducible clindamycin resistance was reported predominantly. Conclusion: The majority of S.aureus was isolated from pus samples, highlighting its importance as a pyogenic microorganism. The current study records a high rate of MRSA resistance among S.aureus isolates. The present study reports a higher rate of inducible clindamycin resistance among MRSA isolates when compared to other phenotypes of clindamycin resistance. Therefore, routine D-testing must be implemented to identify inducible resistance to clindamycin in MRSA to avoid treatment failure.

Phenotypic Resistance of (MRSA) Clinical Isolates to Some Macrolide Antibiotic Groups

Antimicrobial resistance is one of the most significant global threats to human health in recent times, and it limits the achievement of several of the sustainable development goals. Methicillin-resistant Staphylococcus aureus (MRSA) is among the most essential multidrug-resistant bacterial pathogens. The study aimed to determine the prevalence of (MRSA) from different clinical samples to emphasise the suitable treatment. One hundred fifty different clinical samples were collected. All these samples were subjected to classical microbiological testing, which included culturing directly on mannitol salt agar and antibiotic susceptibility test (A.S.T). The results observed that only 32 out of 150 samples of MRSA isolates were identified using cefoxitin 30 (µg) as a screening antibiotic, as suggested by CLSI. These 32 MRSA isolates showed resistance toward penicillin and cefoxitin, high sensitivity against vancomycin, and moderate resistance against doxycycline and azithromycin. Considering the phenotyping resistance toward macrolide antibiotic groups, 10/32 (31.25%) showed S-phenotype,18/32 (52.65%) showed R-phenotype,4/32 (12.5%) showed D-phenotype while no MRSA isolated showed D+ phenotype. This study concludes that inducible clindamycin resistance of S. aureus (MRSA) increases the difficulty of treating S. aureus bacterial infections.

Prevalence and Characterization of Staphylococcus aureus Isolated from Retail Raw Milk Samples in Chennai, India.

Milk is an important source of food, and it is also a nutrient-rich medium, which can harbor multiple microorganisms. Staphylococcus aureus is an important foodborne pathogen in food-producing animals, and there have been many reports on its infection and antimicrobial resistance (AMR), which has significant global public health concerns. This study was designed to isolate, characterize, and analyze the AMR pattern of S. aureus from milk samples collected in Chennai, India. A total of 259 raw milk samples from 3 groups: dairy farms, local vendors, and retail outlets were analyzed, and it was found that 34% (89/259) were positive for S. aureus. Positive isolates were further characterized by pulsed-field gel electrophoresis and isolates recovered from different sources, study areas, and locations showed high genetic diversity with no similarity. The presence of AMR has been further assessed by phenotypic methods as per CLSI-M100 performance standards, and all the isolates were susceptible to ampicillin/sulbactam, mupirocin, and tylosin. Additionally, all of the isolates were resistant to ampicillin. There were 28 isolates categorized as multidrug-resistant, which showed resistance to more than 2-3 classes of antimicrobials. This is the first report of inducible clindamycin resistance and mupirocin sensitivity pattern from S. aureus isolates recovered from milk. This study established the occurrence varied with genetic diversity in the isolates prevalent in the study area and divergence pattern of AMR S. aureus. The AMR in these isolates and with methicillin-resistant S. aureus could pose a serious threat to food safety and economic implications.

Prevalence of methicillin and clindamycin resistant Staphylococcus species at a tertiary hospital in Tanzania: Implications for antibiotic stewardship and infection management

Methicillin and clindamycin resistance (constitutive and inducible) pose a common clinical challenge in treating Staphylococcal infections. This cross-sectional study, conducted at Muhimbili National Hospital (MNH) in Tanzania from April to June 2023, to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and clindamycin-resistant Staphylococcus (S.) species by using a cefoxitin disk (30 μg) and the D-test method as per CLSI 2022 guidelines. Of the 361 clinical samples, 125 (34.6%) were culture-positive. Among Staphylococcus spp., S. aureus was 6% (12/125), while 33.6% (42/125) were coagulase-negative staphylococci (CoNS). Among the isolated S. aureus, 75% were resistant to methicillin, while 66.7% of the CoNS were resistant to methicillin. Further, 92% (11/12) of the S. aureus isolates were resistant to erythromycin, and 50% (6/12) were resistant to clindamycin. Among the CoNS, 83% (35/42) were resistant to erythromycin, and 52% (22/42) were resistant to clindamycin. The proportion of inducible macrolides lincosamide streptogramin B resistance (iMLSB), constitutive macrolides lincosamide streptogramin B resistance (cMLSB), and macrolides lincosamide streptgramin B methicillin susceptible (MS) phenotypes among S. aureus isolates was 16.7%, 41.7%, and 33.3%, respectively, and among CoNS was 19%, 35.7%, and 28.6%, respectively. The overall prevalence of iMLSB and cMLSB phenotypes was 18.5% (10/54) and 37% (20/54), respectively. Comparatively, MRSA had more resistance to ciprofloxacin than methicillin-susceptible S. aureus (MSSA) (88.9% vs. 33.3% p = 0.027), while methicillin-resistant coagulase-negative staphylococci (MR-CoNS) had significantly higher resistance to gentamicin (35.7% vs. 7.1% p= 0.005), and trimethoprim-sulfamethoxazole (78.6% vs. 50% p=0.007) than methicillin-susceptible coagulase-negative staphylococci (MS-CoNS). The high prevalence of methicillin and inducible clindamycin resistance in this study points out a potential rise in treatment failures, prolonged hospitalization, and limited treatment options. Thus, emphasizes the importance of antibiotic stewardship and laboratory-guided antibiotic decisions. To address the growing challenge of antibiotic resistance in Tanzania, it is advisable to implement stringent public health measures, including monitoring antibiotic usage, conducting educational initiatives, and raising awareness among patients and healthcare professionals.

Nasal carriage of methicillin and inducible clindamycin resistant Staphylococcus aureus among healthcare workers in a tertiary care hospital, Kathmandu, Nepal

Introduction and Objectives: Transmission of methicillin-resistant Staphylococcus aureus (MRSA) from healthcare workers is one of the most frequent causes of nosocomial infections globally. There is a significant burden of nosocomial MRSA infections in low and low-middle income countries (LMICs), including Nepal. The present study investigated the rate of nasal carriage of MRSA among the healthcare workers in a tertiary care hospital, in Kathmandu, Nepal with emphasis on inducible macrolide-lincosamide-streptogramin B (iMLSB) resistance. Material and method: The study was conducted at Star Hospital, Lalitpur, Nepal, from September 2022 to November 2022. Healthcare workers (HCWs) working at the diffeerent departments of the hospital were enrolled. Nasal swabs from both anterior nares of HCWs were collected aseptically and cultured on Mannitol Salt agar. S. aureus was identified by Gram stain and standard biochemical tests. Antibiotic susceptibility of S. aureus was performed by disc diffusion method. MRSA isolates were detected phenotypically by disc diffusion method using cefoxitin disc (30 µg), and inducible clindamycin resistance was detected phenotypically by the D-zone test. Results: Total 105 HCWs were enrolled in the study. Out of 105 HCWs, 14 (13.3%) were positive for S. aureus among which 6 (5.7%) were MRSA carriers. The nasal carriage of MRSA was highest among doctors (16.7%) and the HCWs of the post-operative department (14.3%). All the isolated MRSA were susceptible to chloramphenicol and vancomycin. Inducible MLSB resistance was detected in 33.3% MRSA while the rate was 21.4% in all isolated S. aureus. Conclusion: The study demonstrated that HCWs could be the potential source of nosocomial infection by methicillin and inducible clindamycin resistant S. aureus. Thus, preventive measures should be initiated to mitigate the risk of its spread and the test for detection of inducible clindamycin resistance should be incorporated into the routine antibiotic susceptibility testing in hospital settings. IMC J Med Sci. 2024; 18(1):005. DOI: https://doi.org/10.55010/imcjms.18.005 *Correspondence: Gaurab Pandey, Non-Communicable Disease Laboratory, National Public Health Laboratory, Teku, Kathmandu, 44600, Nepal; E-mail: pandeygaurab67@gmail.com

Macrolide-Lincosamide Resistance and Virulence Genes in Staphylococcus aureus Isolated from Clinical Specimens in Ardabil, Iran.

Staphylococcus aureus causes various hospital- and community-acquired infections. This study aimed to investigate the phenotypic and genotypic characteristics of erythromycin and inducible clindamycin resistance, virulence gene profiles, and spa types of S. aureus isolates collected from patients in Ardabil Province, Iran. A total of 118 clinical S. aureus isolates, including 50 (42.4%) methicillin-resistant S. aureus (MRSA) and 68 (57.6%) methicillin-susceptible S. aureus (MSSA) strains, were investigated. Resistance patterns were determined by the disk diffusion method and minimum inhibitory concentration (MIC) test. Inducible macrolide-lincosamide-streptogramin B (iMLSB) resistance was detected using D-test method. The polymerase chain reaction (PCR) was used to identify the virulence and resistance-encoding genes. Additionally, the spa types of the isolates were determined using the PCR, followed by sequencing. In total, 49.1% (58/118) and 44% (52/118) of the isolates were resistant to erythromycin and clindamycin, respectively. Overall, 13.5% (16/118) of the isolates showed the iMLSB resistance phenotype. The ermC gene (72.4% [42]) was the most frequent erythromycin resistance-encoding gene, followed by ermA (60.3% [35]), ermB (60.3% [35]), ermTR (51.7% [30]), and msrA (15.5% [9]) genes among erythromycin-resistant isolates. The virulence genes hla, hld, sea, LukS PV, tst, seb, sed, eta, sec, and etb were detected in 93.2%, 74.5%, 70.3%, 32.2%, 29.6%, 17%, 8.5%, 8.5%, 5.9%, and 4.2% of the isolates, respectively. Ten different spa types were identified for 58 erythromycin-resistant S. aureus strains, of which t030 and t078 types were the most common types. A high frequency of macrolide- and lincosamide-resistant S. aureus isolates with different genetic backgrounds of resistance and virulence may be found in patients in Ardabil Province, Iran.

Distribution of MecA and Erm Genes among Methicillin-resistant Staphylococcus Aureus with Inducible Resistance to Clindamycin.

The emergence of Methicillin-resistant Staphylococcus aureus and its ability to confer cross-resistance to macrolide-lincosamide-streptogramin B has complicated the treatment against it. Gene-based studies among phenotypic methicillin-resistant isolates with inducible resistance to clindamycin are less available in Nepal. This work was undertaken to detect the mecA and erm genes among such phenotypes isolated from clinical samples. S. aureus isolated from different clinical samples was identified by standard microbiological procedures (Gram-staining, colony morphology, and different biochemical tests). Methicillin-resistant and inducible resistant to clindamycin phenotypes were detected by using cefoxitin disc (30 µg) and a double disk diffusion test according to the Clinical and Laboratory Standards Institute guidelines and mecA and erm genes were detected by polymerase chain reaction. Among 120 S. aureus isolates, 51.67% (n=62) were MRSA, and the prevalence of inducibly-resistant, constitutively-resistant and Macrolide-Streptogramin phenotypes were 15.83% (n=19), 28.33% (n=34) and 15.83% (n=19) respectively. While 35.84% (n=43) of isolates showed sensitivity to both antibiotics, erythromycin and clindamycin. Out of 14 inducibly-resistant phenotypes, 57.14% (n=8) were found carrying ermC and 28.57% (n=4) phenotypes contained both ermA and ermC. All phenotypes were positive for the mecA gene. Macrolides-Lincosamide-Streptogramin B resistance was predominant among methicillin-resistant S. aureus. While all isolates with inducible clindamycin resistance harbored mecA gene, most of them also harbored ermC gene. The higher prevalence of inducible-resistant to clindamycin indicated the need for rational use of antimicrobial agents.

Identification of inducible clindamycin resistance gene in Streptococcus agalactiae isolates colonizing pregnant women in Suez Canal University Hospitals

Identification of inducible clindamycin resistance gene in Streptococcus agalactiae isolates colonizing pregnant women in Suez Canal University Hospitals

Agreement between Azithromycin and Erythromycin to Determine Inducible Clindamycin-Resistant Phenotypes in Staphylococcus aureus Isolates

Abstract Objectives To evaluate agreement in the detection of inducible clindamycin resistance by test method using azithromycin disk with reference method using erythromycin disk and to determine prevalence of inducible clindamycin-resistant phenotypes among Staphylococcus aureus isolates. Materials and Methods A total of 133 nonduplicate isolates of S. aureus from clinical samples were included in this prospective study. Agreement between erythromycin (reference method) and azithromycin (test method) disks for detection of inducible clindamycin resistance in S. aureus isolates was assessed. Statistical Analysis Chi-square test was used for analyzing categorical variables (p < 0.05 was considered significant). Results The prevalence of inducible clindamycin resistance (iMLSB) was 15.8%. A 100% agreement was recorded between reference and test methods for detecting inducible clindamycin-resistant phenotypes. For the determination of constitutive-resistant phenotypes (cMLSB) among S. aureus isolates, the test method demonstrated an agreement of 94.1%. Conclusion The present study demonstrated an agreement in the identification of inducible clindamycin-resistant phenotypes among S. aureus isolates by both erythromycin and azithromycin disks.

Antibacterial activity of soil-isolated Bacillus altitudinis/pumilus complex against methicillin-resistant Staphylococcus aureus from Mwanza, Tanzania

Antimicrobial resistance in methicillin-resistant Staphylococcus aureus and beta-lactamase-producing Gram-negative bacteria is a global health concern necessitating research and the development of effective antimicrobial agents. This study, conducted in May 2020 in Mwanza, Tanzania, aimed to determine the antibacterial activity of metabolites from soil-isolated Bacillus species against clinical bacterial pathogens. One soil-isolated Bacillus species, identified as Bacillus altitudinis/pumilus complex, showed antibacterial activity against Gram-positive cocci, including a methicillin-resistant S. aureus strain with inducible clindamycin resistance, previously isolated from a patient with osteomyelitis. Bacillus altitudinis/pumilus complex metabolites may be a potential source of antimicrobial agents against multidrug-resistant bacteria.What this study adds: The study supports existing research on the discovery and development of new antimicrobial agents against multi-drug-resistant bacteria. We report the antimicrobial activity of metabolites extracted from soil-isolated Bacillus altitudinis/pumilus complex strains against Gram-positive bacteria, including a methicillin-resistant Staphylococcus aureus strain with inducible clindamycin resistance

PHENOTYPIC DETERMINATION OF INDUCIBLE CLINDAMYCIN RESISTANT AND METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS FROM CLINICAL ISOLATES OF KHYBER TEACHING HOSPITAL, PESHAWAR

Methicillin Resistant Staphylococcus aureus (MRSA) is a major pathogen involved in nosocomial infections and to some extent, in community acquired infections. Among Macrolide Lincosamine Streptogramin B (MLSB) class of drugs, Clindamycin was vigorously preferred for treating staphylococcal infections in the past few decades but, some genetic factors i.e. erm and msrA genes contribute in developing Inducible Clindamycin Resistance (iCR). Sensitivity tests performed on a routine basis cannot detect inducible resistance and may result in the failure of Clindamycin to be used as an effective medication. This study aimed to detect the phenotype of MRSA and iCR S. aureus from the clinical samples of Khyber Teaching Hospital, Peshawar. A total of 204 samples were collected randomly from each gender, 130 (63.72%) samples were isolated as S. aureus, while 74 (36.27%) were other bacterial species. Double disk diffusion (D-test) was performed to detect iCR phenotype, and 80 (61.5%) isolates showed iCR, while 50 (38.4%) were negative in this regard. MRSA phenotype was determined by strains conferring resistance to Cefoxitin antibiotic, which resulted in 84 (64.6%) isolates of MRSA and 46 (35.3%) of Methicillin Sensitive Staphylococcus aureus (MSSA). Antibiogram analysis showed efficient antimicrobial activity by Tigecycline 129 (99.2%), Fusidic Acid 126 (96.9%), and Doxycycline 124 (95.3%), while the highest resistance pattern was recorded against Ciprofloxacin 31(23.8%) and Clindamycin 28(21.5%). Our study concludes that misuse of antibiotics should be avoided to inhibit the spread of MRSA, and implementation of D-test regularly in hospitals is crucial.

Prevalence of MLSB Phenotypes of <i>Staphylococcus aureus</i> isolates in a tertiary care hospital of Delhi

Against the backdrop of the ever-changing Staphylococcal resistance pattern, clindamycin remains a viable therapeutic alternative Variation of Clindamycin drug resistance patterns with geographic area make inducible clindamycin resistance testing imperative for all staphylococcal isolates to avoid therapeutic failure. This was a prospective study conducted over a period of 1.5 years from January 2021 until June 2022. Prevalence of different MLSB Phenotypes of Staphylococcus aureus isolates was determined by standard disc diffusion method as per CLSI guidelines. Pyogenic samples received in the Microbiology lab that yielded Staphylococcus aureus were further tested for the presence of clindamycin resistance by disc diffusion method. Out of 6586 total pyogenic and respiratory specimens received in the lab, Staphylococcus aureus was yielded in 752 samples. On further testing for the MLSB phenotypes, 16.3% isolates were found to be iMLSB, 19.28% were cMLSB, 43.1% were of MSB type. ICR screening will reduce the unessential subjection of the patient to the antibiotic, and would prevent unnecessary adverse effects in the patients.

Molecular Characteristics of Staphylococcus aureus Strains to Carry Panton-Valentine Leukocidin Genes Isolated from Hospitalized Patients in Tehran, Iran

Background: Staphylococcus aureus with concurrent resistance to antibacterial agents is emerging globally. This emergence might be due to the production of different virulence determinants, notably Panton-Valentine leukocidin (PVL). Objectives: This study aimed to investigate the genetic characteristics of PVL-positive S. aureus strains isolates from clinical samples. Methods: An epidemiological study was conducted on 65 S. aureus isolates carrying pvl genes. An antibiogram test by the disk diffusion and broth microdilution methods was conducted to assess antimicrobial resistance profiles. Results: All detected methicillin-resistant S. aureus (MRSA) isolates were confirmed by mecA polymerase chain reaction (PCR) assays. The PVL-positive isolates were characterized using multiplex PCR assay to detect staphylococcal cassette chromosome mec (SCCmec) and agr types. The PVL frequency was 19.5% and 17.6% in MRSA and methicillin-susceptible S. aureus (MSSA), respectively. Among the PVL-positive isolates, 66.2% and 33.8% were MRSA and MSSA, respectively. Multidrug resistance amounted to 84.6% of the isolates (MRSA: 61.5%, MSSA: 23.1%). Staphylococcal cassette chromosome mec III was dominated (55.8%; 24/43). The most commonly identified agr was type III (53.8%; 35/65). Resistance to vancomycin amounted to 12.3% of the isolates, and all belonged to agr type III and SCCmec type III. The frequency of inducible and constitutive clindamycin resistance among PVL-positive MRSA strains (12.3% and 26.1%) was higher than PVL-positive MSSA strains (7.7% and 15.4%). Most constitutive and inducible clindamycin resistance isolates belonged to agr type III (26.2% and 18.5%) and SCCmec type III (each 27.9%). In the present study, 32.3% of the isolates were confirmed as mupirocin resistant, and all were MRSA, 9 (42.9%) and 12 (57.1%) isolates of which exhibited high-level mupirocin resistant (HLMUPR) and low-level mupirocin resistant phenotypes. All HLMUPR MRSA isolates belonged to SCCmec III and recovered from wound samples. Conclusions: The emergence of vancomycin-resistant S. aureus strains among PVL-positive S. aureus strains in Iran is a serious alarm and seems to be becoming the greatest concern in the treatment of staphylococcal infections in the healthcare setting. The present study reinforces plausible direct transfers between community and nosocomial PVL-positive S. aureus types.

Genomic characterization of emerging invasive Streptococcus agalactiae serotype VIII in Alberta, Canada

Invasive Group B Streptococcus (GBS) can infect pregnant women, neonates, and older adults. Invasive GBS serotype VIII is infrequent in Alberta; however, cases have increased in recent years. Here, genomic analysis was used to characterize fourteen adult invasive serotype VIII isolates from 2009 to 2021. Trends in descriptive clinical data and antimicrobial susceptibility results were evaluated for invasive serotype VIII isolates from Alberta. Isolate genomes were sequenced and subjected to molecular sequence typing, virulence and antimicrobial resistance gene identification, phylogenetic analysis, and pangenome determination. Multilocus sequencing typing identified eight ST42 (Clonal Complex; CC19), four ST1 (CC1), and two ST2 (CC1) profiles. Isolates were susceptible to penicillin, erythromycin, chloramphenicol, and clindamycin, apart from one isolate that displayed erythromycin and inducible clindamycin resistance. All isolates carried genes for peptide antibiotic resistance, three isolates for tetracycline resistance, and one for macrolide, lincosamide, and streptogramin resistance. All genomes carried targets currently being considered for protein-based vaccines (e.g., pili and/or Alpha family proteins). Overall, invasive GBS serotype VIII is emerging in Alberta, primarily due to ST42. Characterization and continued surveillance of serotype VIII will be important for outbreak prevention, informing vaccine development, and contributing to our understanding of the global epidemiology of this rare serotype.

PHENOTYPIC DETECTION OF INDUCIBLE CLINDAMYCIN RESISTANCE IN STAPHYLOCOCCUS SPECIES ISOLATED FROM CLINICAL SAMPLES IN A TERTIARY CARE HOSPITAL

Introduction: Clindamycin is an effective drug used as an alternative to Vancomycin to treat skin and soft tissue infections caused by Staphylococcus spp. Reporting Staphylococcus as susceptible to Clindamycin without checking for inducible Clindamycin resistance may lead to therapeutic failure. Aim: To detect inducible Clindamycin resistance (MLSBi) among clinical isolates of Staphylococci by using a simple double-disc diffusion test (D-test). Methods: It was a prospective study conducted for 6 months from June 2022 to November 2022. All the Staphylococcal isolates from various samples were taken . Inducible clindamycin resistance (MLSBi) was detected by Erythromycin and Clindamycin disc approximation test (D-test) following CLSI guidelines. Results: A total of 216 Staphylococcus species were isolated from different samples. Out of the total samples Staphylococcus aureus were 42% and Coagulase negative Staphylococcus (CoNS) were 58%. Sensitivity to vancomycin, linezolid and teicoplanin were 100%. Methicillin resistance is seen in 21% of Staphylococcus aureus and 23% of CoNS. The different susceptibility patterns to clindamycin in both Staphylococcus aureus and CoNS were noted. Constitutive (MLSBc) phenotype was most prevalent (48%) followed by MS phenotype (43%) and inducible (MLSBi) phenotype (9%) among Erythromycin resistant Staphylococcus isolates. Sensitive phenotype (S) is detected in 27%. MLSBi was more frequent in Methicillin Resistant Staphylococcus aureus (MRSA) (28%) and MRCoNS (10%) than in MSSA (4%) and MSCoNS (2%). Conclusion: D-test should be included as a mandatory method in routine disc diffusion antimicrobial testing to detect inducible Clindamycin resistance in Staphylococci for the optimum treatment of patients.