A standardised approach to the treatment and management of significant acinetobacter species infection at academic complex hospitals in KwaZulu-Natal.

Doctoral Degree. University of KwaZulu-Natal, Durban.Introduction: Carbapenem-resistant Acinetobacter species (Acinetobacter spp.) are increasingly recognised as important pathogens, whose resistance patterns present a high-risk global challenge. However, there is limited scientific data and a lack of a standardised approach to help the clinician select optimal therapy in local setting. This study aimed to provide a standardised approach for the management of significant Acinetobacter spp. infection based on phenotypic and genotypic characterisation of local isolates, as well as clinical characteristics and outcomes of patients at academic complex hospitals in KwaZulu-Natal. Objectives: The significance of Acinetobacter spp. infections and the most effective drug combinations for optimal therapy were determined. Acinetobacter spp. isolates were phenotypically and genotypically characterised. This was followed by the development of a standard management guideline for local use, based on the data obtained in the different objectives. Methods: The research consisted of a retrospective and prospective observational and experimental laboratory component. The laboratory component included synergy testing of colistin, susceptibility to antimicrobial agents in use at local hospitals, polymerase chain reaction and sequencing for analysis of the resistant genes related to carbapenem, colistin and amikacin. Phenotypic, genotypic, and clinical characterisation were utilised to develop a standardised management approach of significant Acinetobacter spp. infection. Results: Acinetobacter spp. was identified as a significant cause of sepsis and mortality among patients in a surgical intensive care unit (ICU). Cases of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Acinetobacter spp. increased over seven years, together with the emergence of pandrug-resistant (PDR) isolates. The results of synergy testing of colistin combinations with amikacin, carbapemens (imipemen, meropenem), ciprofloxacin, tazocin, linezolid, rifampicin and vancomycin against Acinetobacter spp. was highly diverse and speciesdependent. Characterisation of Acinetobacter spp. isolates showed that oxacillinase β-lactamase (OXA-23)-producing MDR isolates correlated with their antibiogram. Pulsed field gel electrophoresis (PFGE) showed horizontal transfer between seven clusters, each containing two patients each, totalling 14 patients. However, the PFGE typing revealed a diverse collection of MDR Acinetobacter spp. clones, and that isolates from not more than two patients were related. This suggests, therefore, that no outbreak had occurred based on the PFGE typing interpretation. Further genetic investigation revealed that the aphA6 gene were associated with amikacin resistance and IpxA gene may be associated with colistin resistance in our local setting. Conclusion: The results highlighted the importance of antibiotic stewardship in the treatment of Acinetobacter spp. infection. Individual-specific antibiograms are recommended as the best 2 approach for treatment in KwaZulu-Natal (KZN) and synergy testing should be performed for individualised direct therapy. The clinical and microbiological indicators of significant infection are crucial when establishing the decision to treat. The study provided a valuable standardised approach, including a flow chart of criteria for sepsis and colonisation; a standardised algorithm for the management; and synergy test at academic complex hospitals, Medical Microbiology laboratory, National Health Laboratory Service (NHLS) in KZN

Antimicrobial susceptibility of bacterial uropathogens in a South African regional hospital

Background: Urinary tract infections are common bacterial infections affecting millions worldwide. Although treatment options for urinary tract infections are well established, with ciprofloxacin long considered one of the antibiotics of choice, increasing antibiotic resistance may delay the initiation of appropriate therapy. While this increase in antimicrobial resistance has been demonstrated in multiple studies around the world, there is a dearth of information from developing countries. Objective: This study aimed to describe the antimicrobial susceptibility patterns of commonly isolated bacterial uropathogens in a South African hospital. Methods: Antimicrobial susceptibility data of isolates obtained from urine specimens at the RK Khan Hospital, a regional hospital in KwaZulu-Natal, South Africa, between January 2018 and December 2020 were retrieved from the hospital’s laboratory information system and analysed to determine the differences in resistance rates between the most frequently isolated bacterial uropathogens. Results: Of the 3048 bacterial urinary pathogens isolated between 2018 and 2020, Escherichia coli (1603; 53%) was the most common, followed by Klebsiella spp. (437; 14%). Both E. coli and Klebsiella spp. showed high rates of resistance to amoxicillin/clavulanic acid (29.8% and 42.3%) and ciprofloxacin (37.7% and 30.4%). Nitrofurantoin resistance was low among E. coli (6.2%) but high among Klebsiella spp. (61.3%). Conclusion: E. coli and Klebsiella spp. in this study were highly resistant to amoxicillin/clavulanic acid and ciprofloxacin, two of the frequently prescribed oral treatment options. What this study adds: This study highlights the importance of regular local antimicrobial resistance surveillance to inform appropriate empiric therapy

National sentinel site surveillance for antimicrobial resistance in Klebsiella pneumoniae isolates in South Africa, 2010-2012

Please cite as follows: Perovic, O. et al. 2014. National sentinel site surveillance for antimicrobial resistance in Klebsiella pneumoniae isolates in South Africa, 2010-2012. South African Medical Journal, 104(8):563-568, doi:10.7196/SAMJ.7617.The original publication is available at http://www.samj.org.zaBackground. The increasing rates of antimicrobial resistance observed in the nosocomial pathogen Klebsiella pneumoniae are of major public health concern worldwide. Objectives. To describe the antibiotic susceptibility profiles of K. pneumoniae isolates from bacteraemic patients submitted by sentinel laboratories in five regions of South Africa from mid-2010 to mid-2012. Molecular methods were used to detect the most commonly found extended-spectrum beta-lactamase (ESBL) and carbapenemase resistance genes. Methods. Thirteen academic centres serving the public healthcare sector in Gauteng, KwaZulu-Natal, Free State, Limpopo and Western Cape provinces submitted K. pneumoniae isolates from patients with bloodstream infections. Vitek 2 and MicroScan instruments were used for organism identification and susceptibility testing. Multiplex polymerase chain reactions (PCRs) were used to detect blaCTX-M, blaSHV and blaTEM genes in a proportion of the ESBL isolates. All isolates exhibiting reduced susceptibility to carbapenems were PCR tested for blaKPC and blaNDM-1 resistance genes. Results. Overall, 68.3% of the 2 774 isolates were ESBL-positive, showing resistance to cefotaxime, ceftazidime and cefepime. Furthermore, 46.5% of all isolates were resistant to ciprofloxacin and 33.1% to piperacillin-tazobactam. The major ESBL genes were abundantly present in the sample analysed. Most isolates (95.5%) were susceptible to the carbapenems tested, and no isolates were positive for blaKPC or blaNDM-1. There was a trend towards a decrease in susceptibility to most antibiotics. Conclusion. The high proportion of ESBL-producing K. pneumoniae isolates observed, and the prevalence of ESBL genes, are of great concern. Our findings represent a baseline for further surveillance in SA, and can be used for policy and treatment decisions.http://www.samj.org.za/index.php/samj/article/view/7617Publisher's versio

National sentinel site surveillance for antimicrobial resistance in Klebsiella pneumoniae isolates in South Africa, 2010 - 2012

Background. The increasing rates of antimicrobial resistance observed in the nosocomial pathogen Klebsiella pneumoniae are of major public health concern worldwide.Objectives. To describe the antibiotic susceptibility profiles of K. pneumoniae isolates from bacteraemic patients submitted by sentinel laboratories in five regions of South Africa from mid-2010 to mid-2012. Molecular methods were used to detect the most commonly found extended-spectrum beta-lactamase (ESBL) and carbapenemase resistance genes.Methods. Thirteen academic centres serving the public healthcare sector in Gauteng, KwaZulu-Natal, Free State, Limpopo and Western Cape provinces submitted K. pneumoniae isolates from patients with bloodstream infections. Vitek 2 and MicroScan instruments were used for organism identification and susceptibility testing. Multiplex polymerase chain reactions (PCRs) were used to detect blaCTX-M, blaSHV and blaTEM genes in a proportion of the ESBL isolates. All isolates exhibiting reduced susceptibility to carbapenems were PCR tested for blaKPC and blaNDM-1 resistance genes.Results. Overall, 68.3% of the 2 774 isolates were ESBL-positive, showing resistance to cefotaxime, ceftazidime and cefepime. Furthermore, 46.5% of all isolates were resistant to ciprofloxacin and 33.1% to piperacillin-tazobactam. The major ESBL genes were abundantly present in the sample analysed. Most isolates (95.5%) were susceptible to the carbapenems tested, and no isolates were positive for blaKPC or blaNDM-1. There was a trend towards a decrease in susceptibility to most antibiotics.Conclusion. The high proportion of ESBL-producing K. pneumoniae isolates observed, and the prevalence of ESBL genes, are of great concern. Our findings represent a baseline for further surveillance in SA, and can be used for policy and treatment decisions

Analysis of clinical and microbiological data on Acinetobacter baumannii strains assist the preauthorization of antibiotics at the patient level for an effective antibiotic stewardship program

Drug resistant Acinetobacter baumannii (A. baumannii) poses serious treatment challenges and is on the rise worldwide. The Infectious Diseases Society of America/Society for Healthcare Epidemiology of America recommends preauthorization of antibiotics to ensure successful antibiotic stewardship programs (ASWPs). This study estimates and analyzes the microbiological and clinical characteristics of A. baumanii strains with differentiating criteria for sepsis versus colonization, in order to support preauthorization and assist ASWPs at the patient level.A retrospective observational study was performed from 2008 to 2014. The clinical and microbiological characteristics of A. baumannii strains were correlated to assess pathogenic status and antibiotic resistance patterns. A flow chart was produced to differentiate between sepsis and colonization amongst patient groups.A. baumannii was cultured in 2656 cases, with a prevalence of 0.9–2.4% during 7 years study periods. There was a statistically significant difference between the sepsis and colonization groups (P = 0.02). Sepsis accounted for 37–51% of A. baumanii isolates and colonisation for 49–63% (P = < 0.01). Multidrug resistant (MDR), extensive drug resistant (XDR) and pandrug resistant (PDR) A. baumannii was detected in 53–60%, 1–19% and 1% of cultures in the sepsis group, and 75%, 8–23% and 1% in the colonized group. There was a high percentage of polymicrobial infection in the sepsis group and pure growth was not always significant for sepsis.Cases of MDR and XDR A. baumannii increased over the seven-year study, while PDR strains emerged. For a successful ASWP, both clinical and microbiological information should be interpreted when establishing preauthorization/decision to treat. Keywords: MDR, XDR, PDR A. baumannii, Prevalence, Sepsis, Colonized group, Preauthorization, Antibiotic stewardship progra

Association of Staphylococcus nasal colonization and HIV in end-stage renal failure patients undergoing peritoneal dialysis

Introduction: Staphylococcal infections can cause significant morbidity in patients undergoing dialysis. This study evaluated the effects of HIV infection on nasal carriage of Staphylococcus aureus, staphylococcal peritonitis, and catheter infection rates in patients with end-stage renal failure managed with continuous ambulatory peritoneal dialysis (CAPD). Methods: Sixty HIV-positive and 59 HIV-negative CAPD patients were enrolled and followed up for up to 18 months. S. aureus nasal carriage (detected by nasal swab culture), Staphylococcal peritonitis (diagnosed by clinical presentation, and CAPD effluent Staphylococcal culture and white blood cell count ≥100 cells/µL), and catheter infections (including exit site and tunnel infections) were assessed monthly. Results: At 18 months, S. aureus nasal carriage rates were 43.3% and 30.5% (p = 0.147) and the methicillin-resistant S. aureus (MRSA) nasal carriage rates were 31.7% and 13.6% (p = 0.018) for the HIV-positive and HIV-negative cohorts, respectively. The HIV-positive cohort was associated with increased hazards for staphylococcal peritonitis, (adjusted hazard ratio [AHR] 2.85, 95% confidence interval [CI] 1.19–6.84, p = 0.019) due to increased coagulase-negative staphylococcal (CNS) peritonitis rate in the HIV-positive cohort compared with the HIV-negative cohort (0.435 vs. 0.089 episodes/person-years; AHR 7.64, CI 2.18–26.82, p = 0.001). On multivariable analysis, CD4+ cell count <200 cells/µL, diabetes, and S. aureus nasal carriage were found to be independent predictors of S. aureus peritonitis. Conclusions: These findings suggest that HIV infection may be a risk factor for MRSA nasal colonization and may increase the risks of CNS peritonitis, while a CD4+ cell count <200 cells/µL and S. aureus nasal carriage may be important predictors of S. aureus peritonitis