Genomic Insights into and In Vitro Evaluation of Antimicrobial Combination Therapies for Carbapenem-Resistant Acinetobacter baumannii.

Background and Objectives: Acinetobacter baumannii (A. baumannii), particularly carbapenem-resistant A. baumannii (CRAB), represents a grave concern in healthcare settings and is associated with high mortality. This study aimed to conduct molecular, mutational, and phylogenetic analyses of specific genes in CRAB and evaluate the synergistic effects of selected antimicrobial combinations. Materials and Methods: Phenotypic characterization was performed on six CRAB strains by using the Modified Hodge Test (MHT) and IMP-EDTA Double-Disc Synergy Test (IMP-EDTA DDST). Carbapenemase- and metallo-beta-lactamase-encoding genes were amplified by using Polymerase Chain Reaction. Phylogenetic analysis using the MEGA 11 tool was used to determine the evolutionary relatedness of these genes. Mutational analysis was performed by using I-Mutant, MUPro, and PHD-SNP bioinformatics tools to predict mutations in the carbapenemase-encoding genes. Microdilution checkerboard titration assessed the synergistic effects of antimicrobial combinations (azithromycin-meropenem, rifampicin-meropenem, meropenem-colistin, and azithromycin-colistin) on these CRAB isolates. Results: The phenotypic characterization of six CRAB isolates revealed positive results for MHT and IMP-EDTA DDST. The molecular characterization revealed that carbapenemase- and MBL-encoding genes were present in all isolates with varying frequencies, including blaOXA-51 (100%) and blaIMP (0%). The sequence analysis revealed high evolutionary relatedness to sequences in the NCBI database. The mutational analysis identified 16 mutations, of which 1 mutation (P116L) in the blaOXA-58 gene predicted a change in the protein product, potentially contributing to carbapenem resistance. The checkerboard titration method did not reveal any synergism among the tested antimicrobial combinations against CRAB. Conclusion: This study's findings underscore the significant challenges posed by CRAB isolates harboring multiple resistant genes in treatment. This highlights the urgent need for novel antimicrobial agents, a crucial step towards reducing mortality rates not only in Pakistan but also globally.

Correction: Saeed, A., et al. Incidence of Vancomycin-Resistant Phenotype of the Methicillin-Resistant Staphylococcus aureus Isolated from a Tertiary Care Hospital in Lahore. Antibiotics 2020, 9, 3.

Staphylococcus aureus (S. aureus)-associated infections are one of the major threats to public health. The aim of the present study was to determine the antibiotic resistance pattern, as well as the genetic characterization, of methicillin and vancomycin-resistant S. aureus (VRSA) isolated from a tertiary care hospital in Lahore. The S. aureus isolates were isolated from different clinical samples, identified by biochemical testing, and subjected to antibiotic susceptibility testing via the disc diffusion method or broth microdilution method. The methicillin resistance gene (mecA) and vancomycin resistance gene (vanA) were amplified by the polymerase chain reaction. The S. aureus isolates showed high incidences of resistance against methicillin (76%) and moderate incidences of resistance to vancomycin (14%). Isolates were also resistant to several other drugs, such as cefoxitin (76%), ertapenem (83%), ampicillin (81%), tobramycin (78%), moxifloxacin (76%), and tetracycline (74%). An encouraging finding was that 98% of isolates were susceptible to tigecycline, indicating its possible role in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) and VRSA, as well as the multi-drug resistant S. aureus. The mecA gene was detected in 33.3% of tested isolates (10/30), while the vanA gene was also detected in 30% (9/30) of the tested isolates. In conclusion, the frequent presence of methicillin and vancomycin resistance in S. aureus appraises the cautious use of these antibiotics in clinical practices. Furthermore, it is suggested that there should be continuous monitoring of tigecycline treatments in clinical setups in order to delay the development of resistance against it.

Incidence of Vancomycin Resistant Phenotype of the Methicillin Resistant Staphylococcus aureus Isolated from a Tertiary Care Hospital in Lahore.

Staphylococcus aureus (S. aureus) associated infections are one of the major threats to public health. The aim of the present study was to determine the antibiotic resistance pattern as well as the genetic characterization of methicillin and vancomycin resistant S. aureus (VRSA) isolated from a tertiary care hospital in Lahore. The S. aureus were isolated from different clinical samples, identified by biochemical testing, and subjected to antibiotic susceptibility testing by disc diffusion method or broth microdilution method. Methicillin resistance gene (mecA) and vancomycin resistance gene (vanA) were amplified by polymerase chain reaction. The S. aureus isolates showed high incidence of resistance against methicillin (76%) and moderate incidence of resistance to vancomycin (44%). Isolates were also resistant to several other drugs such as cefoxitin (76%), ertapenem (83%), ampicillin (81%), tobramycin (78%), moxifloxacin (76%), and tetracycline (74%). An encouraging finding was that 98% of isolates were susceptible to tigecycline, indicating its possible role in the treatment of MRSA, VRSA, as well as multi-drug resistant S. aureus. The mecA gene was detected from 33.3% (10/30) while vanA gene was detected from 46.6% (14/30) of the tested isolates. In conclusion, frequent presence of methicillin and vancomycin resistance in S. aureus appraises the cautious use of these antibiotics in clinical practices. Furthermore, it is suggested that there should be continuous monitoring of tigecycline treatments in clinical setups in order to delay the development of resistance against it.

Methicillin-resistant Staphylococcus aureus nasal colonisation amongst healthcare workers in Kurdistan Region, Iraq.

OBJECTIVES: The aim of this study was to determine the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers (HCWs) compared with non-HCWs at Duhok city, Kurdistan Region, northern Iraq. METHODS: A total of 182 HCWs with different occupations and working in different hospital units as well as 198 non-HCWs were recruited. Nasal swab samples were collected and were inoculated on mannitol salt agar and incubated at 35°C for 48h. Isolates identified as S. aureus underwent antimicrobial sensitivity testing to oxacillin. MRSA isolates were selected and investigated for presence of the mecA gene. RESULTS: Among the HCWs, 41/182 (22.5%) were carriers of S. aureus compared with 37/198 (18.7%) non-HCWs (P=0.4). Amongst the S. aureus carriers, 25/41 strains (61.0%) isolated from HCWs were MRSA compared with 8/37 strains (21.6%) isolated from non-HCWs (P=0.039). The mean age of MRSA carriers was 35.6±6.7years compared with 30±5.8years for MRSA non-carriers (P=0.0177). The mean working years of MRSA carriers was significantly higher than that of MRSA non-carriers (7.8±5.5years vs. 3.9±5.3years; P=0.04). CONCLUSIONS: The prevalence of MRSA was very high amongst HCWs. Regular screening of carriers is required for prevention of nosocomial infections.

SOCIO-DEMOGRAPHIC STUDY OF HEPATITIS C PATIENTS VISITING TERTIARY CARE HOSPITAL.

BACKGROUND: Hepatitis C is a very common blood-borne disease of liver caused by Hepatitis C Virus and about two third of these patients will ultimately end up having liver cirrhosis or hepatocellular carcinoma. This study was carried out to determine the sociodemographic status of the hepatitis C infected patients visiting tertiary care hospitals in Lahore, Pakistan. METHODS: This study was conducted during the months of October and November 2009. In this cross sectional study, 154 volunteer patients of HCV were included. They were investigated for sociodemographic variables and were statistically analysed by SPSS-15. RESULTS: Of these 154 patients, a high percentage of patients were females (70.1%). Majority of the patients belonged to the families of labour occupation (39.4%) of which 71.4 % were illiterate. Gender was found significantly associated with categories of sleep disturbance (p<0.05) and tension (p<0.05) among HCV patients. Married patients were significantly associated with tension (p<0.05) and a significant emotional and behavioural change in their attitude was also found (p<0.05). Patients with shorter interval after first diagnosis of the disease felt more emotional and had greater behavioural changes in their attitude (p<0.05). CONCLUSION: Incidence of Hepatitis C was higher in females and married females with shorter interval after first diagnosis of the disease were more depressed.

Susceptibility of methicillin-resistant Staphylococcus aureus and enterococci to teicoplanin in Pakistan: the MRSET study.

OBJECTIVE: To evaluate the susceptibility pattern of S. aureus and enterococci to teicoplanin using an in vitro method. METHODS: Between February and November 2011, valid bacteriological samples were collected at three hospitals in three cities in Pakistan and the organism was isolated. Only samples containing S. aureus or enterococci were tested for their sensitivity to teicoplanin and various other standard antimicrobials in therapy, using the disc diffusion testing by the Kirby-Bauer method. SPSS 18 was used for statistical analysis. RESULTS: Of the 401 isolates collected, a majority 293 (59.6%) were methicillin-sensitive S. aureus, while 136 (33.9%) were methicillin-resistant S. aureus; and 26 (6.5%) were enterococci. All isolates were sensitive to teicoplanin and vancomycin. CONCLUSION: Teicoplanin had the same in vitro sensitivity as vancomycin against methicillin-sensitive S. aureus, methicillin-resistant S. aureus and enterococci in clinical isolates.

Isolation and antibiotic susceptibility of E. coli from urinary tract infections in a tertiary care hospital.

OBJECTIVE: The study was conducted to isolate and determine the antibiotic resistance in E. coli from urinary tract infections in a tertiary care hospital, Lahore. METHODS: Urine samples (n=500) were collected from patients with signs and symptoms of Urinary tract infections. Bacteria were isolated and identified by conventional biochemical profile. Antibiotic resistance pattern of E. coli against different antibiotic was determined by Kirby-Baur method. RESULTS: Bacterial etiological agent was isolated from 402 samples with highest prevalence of E. coli (321, 80%) followed by Staphylococcus aureus (9.4%), Proteus species (5.4%) and Pseudomonas species (5.2%). The E. coli were highly resistant to penicillin (100%), amoxicillin (100%) and cefotaxime (89.7%), followed by intermediate level of resistance to ceftazidime (73.8%), cephradine (73.8%), tetracycline (69.4%), doxycycline (66.6%), augmentin (62.6%), gentamycin (59.8%), cefuroxime (58.2%), ciprofloxacin (54.2%), cefaclor (50%), aztreonam (44.8%), ceftriaxone (43.3%), imipenem (43.3%), and low level of resistance to streptomycin (30%), kanamycin (19.9%), tazocin (14%), amikacin (12.7%) and lowest to norfloxacin (11.2%). Out of 321 E. coli isolates, 261 (81%) were declared as multiple drug resistant and 5 (1.5%) were extensive drug resistant. CONCLUSION: It is concluded that most of the urinary tract infections in human are caused by multiple drug resistant E. coli.