A high level of antibiotic resistance in Klebsiella and Aeromonas isolates from street water sold in Mozambique, associated with the prevalence of extended-spectrum and AmpC ß-lactamases

The importance of "one health approach" to the AMR study and surveillance in Angola and other African countries

The dissemination of multidrug-resistant (MDR) bacterial isolates in low- and middle-income countries, including several African countries, is a major concern. The poor sanitary conditions of rural and urban families observed in certain regions may favor the transmission of bacterial infections between animals and humans, including those promoted by strains resistant to practically all available antibiotics. In Angola, in particular, the presence of these strains in human hospitals has already been described. Nevertheless, the information on antimicrobial resistance (AMR) prevalence in Angola is still scarce, especially regarding veterinary isolates. This review aimed to synthesize data on antimicrobial resistance in African countries, with a special focus on Angola, from a One Health perspective. The main goals were to identify research gaps that may require further analysis, and to draw attention to the importance of the conscious use of antimicrobials and the establishment of preventive strategies, aiming to guarantee the safeguarding of public health. To understand these issues, the available literature on AMR in Africa was reviewed. We searched PubMed for articles pertinent to AMR in relevant pathogens in Angola and other African countries. In this review, we focused on AMR rates and surveillance capacity. The principal findings were that, in Africa, especially in sub-Saharan countries, AMR incidence is high due to the lack of legislation on antibiotics, to the close interaction of humans with animals and the environment, and to poverty. The information about current resistance patterns of common pathogenic bacteria is sparse, and the number of quality studies is limited in Angola and in some other Sub-Saharan African countries. Also, studies on the "One Health Approach" focusing on the environment, animals, and humans, are scarce in Africa. The surveillance capacity is minimal, and only a low number of AMR surveillance programs and national health programs are implemented. Most international and cooperative surveillance programs, when implemented, are not properly followed, concluded, nor reported. In Angola, the national health plan does not include AMR control, and there is a consistent omission of data submitted to international surveillance programs. By identifying One Health strengths of each country, AMR can be controlled with a multisectoral approach and governmental commitment.

Multidrug Resistance in Enterococci Isolated from Cheese and Capable of Producing Benzalkonium Chloride-Resistant Biofilms

This study aimed to investigate enterococci recovered from eight Portuguese cheeses made with raw ewe's milk, regarding antibiotic resistance, virulence genes, minimum inhibitory concentration (MIC) of benzalkonium chloride (BAC), biofilm formation capacity, and biofilm eradication (MBEC) by BAC. Antimicrobial resistance against seven antibiotics of five groups was evaluated using the disk diffusion method. The presence of the genes that encode resistance to the antibiotics penicillin (blaZ), erythromycin (ermA, ermB, and ermC), vancomycin (vanA and vanB), aminoglycoside (aac(6')-Ie-aph(2″)-Ia), and β-lactam (pbp5) and the genes that encode virulence factors, frsB, cylA, gelE, esp, and agg, were investigated via multiplex PCR. The susceptibility of planktonic cells to BAC was evaluated by the MIC and MBC values of the isolates, using the broth microdilution method. To assess the biofilm-forming ability and resistance of biofilms to BAC, biofilms were produced on stainless steel coupons, followed by exposure to BAC. The results showed a high resistance to the antibiotics vancomycin (87.5%), erythromycin (75%), tetracycline (50%), and penicillin (37.5%). Multidrug resistance was observed in 68.8% of the isolates. Genes encoding the virulence factors FrsB (frsB) and gelatinase E (gelE) were detected in all isolates. The esp and cylA genes were found in 56.3% and 37.5% of the isolates, respectively. All isolates exhibited a biofilm-forming ability, regardless of incubation time and temperature tested. However, after 72 h at 37 °C, E. faecium and E. faecalis biofilms showed significant differences (p ≤ 0.05). Although most isolates (62.5%) were susceptible to BAC (MIC ≤ 10 mg/L), biofilms of the same isolates were, generally, resistant to the higher concentration of BAC (80 mg/mL) tested. This study using Enterococcus isolates from a ready-to-eat food, such as cheese, reveals the high percentages of vancomycin resistance and multidrug resistance, associated with the presence of virulence genes, in isolates also capable of producing biofilms resistant to BAC, an important active ingredient of many disinfectants. These results emphasize the need for effective control measures to ensure the safety and quality of dairy products.

The Socioeconomic Factors of Street Food Vending in Developing Countries and Its Implications for Public Health: A Systematic Review

The sale of ready-to-eat (RTE) street food represents an important source of income in many developing countries. However, these foods are frequently implicated in outbreaks of gastrointestinal diseases. Street food vendors face several constraints that hamper improvement in the microbiological quality of their products. The aim of this review was to update knowledge about the main causes of foodborne illnesses in developing countries, including the growing concern with the microbial transmission of antibiotic resistance. Following PRISMA guidelines, this systematic review was conducted on original articles published from January 2010 to July 2023. The search was carried out using Scopus, PubMed, Web of Science, Food Science and Technology Abstracts (FSTA), the International Information System for Agricultural Sciences and Technology (AGRIS), as well as isolated searches of relevant articles from Google Scholar. The initial search identified 915 articles, 50 of which were included in this systematic review. The results indicate that, in the majority of the 15 countries examined, women constitute the predominant segment of street food vendors, representing more than 55% of the total number of these vendors. In 11 countries, street food vendors under the age of 18 were identified. Most vendors had a low level of education and, consequently, were unaware of good hygiene practices when handling food. The combination of factors such as poor hygiene practices on the part of food handlers and the lack of facilities, namely, the absence of available potable water, were frequently listed as the main causes of food contamination. Enterobacteriaceae such as Escherichia coli (61.9%), Salmonella (30.1%), and Shigella spp. (9.5%), as well as Staphylococcus aureus (30.1%) and Listeria monocytogenes (14.3%), were the most common pathogens found in RTE street foods. In 22 studies from 13 developing countries, 59% (13/22) reported high multidrug resistance in Enterobacteriaceae (40% to 86.4% in E. coli, 16.7 to 70% in Salmonella, and 31 to 76.4% in S. aureus). To address the challenges faced by street vendors and improve their economic activities, it is necessary for government entities, consumers, and vendors to work together collaboratively.

Susceptibility antibiotic screening reveals high rates of multidrug resistance of Salmonella, Shigella and Campylobacter in HIV infected and uninfected patients from Mozambique

BACKGROUND

Antibacterial resistance is a growing concern worldwide, including in Mozambique. Diarrhea is an important cause of mortality in Mozambique, yet few local studies have reported on the resistance of bacterial pathogens in this context. Therefore, this study aims to characterize antibiotic susceptibility patterns of Salmonella, Shigella and Campylobacter spp. among patients with diarrhea, including those who are HIV-infected and-uninfected.

METHODS

We conducted antibiotic susceptibility testing on 157 stool isolates recovered from 129 patients aged between 0 and 80 years with diarrhea, including HIV infected (n = 68) and-uninfected individuals (n = 61), assisted at two health centers in Maputo city. The isolates comprised of 99 Salmonella, 45 Shigella and 13 Campylobacter strains. The Kirby-Bauer disk diffusion method was used on Mueller-Hinton II agar for Salmonella and Shigella spp., while Mueller-Hinton II agar with 5% defibrinated sheep blood was used for Campylobacter spp. We tested six antibiotics listed on the national essential medicines list, including ciprofloxacin, erythromycin, azithromycin, trimethoprim-sulfamethoxazole, gentamicin, and tetracycline.

RESULTS

All isolates were resistant to at least one antibiotic. A high percentage of Salmonella spp. isolates were found to be resistant to trimethoprim-sulfamethoxazole (89.9%, n = 89), erythromycin (88.9%, n = 88) and tetracycline (76.8%, n = 76). In addition, 86.6% (n = 39) and 68.9% (n = 31) of Shigella isolates were resistant to trimethoprim-sulfamethoxazole and tetracycline, respectively. The majority of Campylobacter isolates (92.3%, n = 12) were resistant to erythromycin, azithromycin and tetracycline. Multidrug resistance (MDR) was observed in 79.8% of Salmonella spp., 76.9% of Campylobacter spp., and 57.8% of Shigella spp. Drug susceptibility profiles for Salmonella spp. and Campylobacter were similar in both HIV-1 infected and uninfected patients. However, Shigella spp. isolates obtained from patients without HIV infection were significantly more likely to be resistant to erythromycin, azithromycin or to exhibit multidrug resistance than those obtained from patients with HIV-1 infection (p < 0.05). All Shigella spp. and Campylobacter spp. isolates were susceptible to gentamicin.

CONCLUSION

Our study highlights concerning rates of antibiotic resistance and MDR among diarrheal bacterial pathogens in Mozambique. Further research is needed to understand the impact of HIV, ART therapy and immunosuppression on antibiotic resistance. Urgent interventions are essential to prevent the spread of resistant strains.

Enterotoxin- and Antibiotic-Resistance-Encoding Genes Are Present in Both Coagulase-Positive and Coagulase-Negative Foodborne Staphylococcus Strains

Food poisoning by staphylococcal enterotoxins (SE) is a major cause of foodborne illness, often associated with coagulase-positive staphylococci (CPS). The increase in the number of methicillin-resistant Staphylococcus aureus (MRSA) strains is another major problem associated with CPS. However, reports of the association of SE and methicillin-resistant Staphylococcus with coagulase-negative staphylococci (CNS) are beginning to re-emerge. In this context, the aim of this study is to investigate the presence of staphylococcal enterotoxin genes and to characterize the phenotypic and genotypic antimicrobial resistance in 66 isolates of Staphylococcus spp. (47 CNS and 19 CPS) recovered from ready-to-eat (RTE) street food sold in Maputo, Mozambique. Seven virulence genes encoding SE (sea, seb, sec, sed and see) and two toxins (hlb and sak) were screened by multiplex PCR (MPCR). Antimicrobial resistance against 12 antibiotics was evaluated by the disk diffusion method. The presence of genes encoding resistance to penicillin, methicillin, vancomycin and erythromycin (blaZ, mecA, vancA, vancB, ermA, ermB and ermC) were also screened by PCR. At least one of the seven virulence genes assessed in this study was detected in 57.9% and 51% of CPS and CNS isolates, respectively. In CPS isolates, the most frequent gene was hlb (47.4%), followed by sec (15.8%) and sea, seb and sed genes with 5.3% each. In CNS isolates, the most frequent gene was sec (36.2%) followed by sak (17%), hlb (14.9%), sed (12.8%) and seb (6.4%). Five of the twelve CPS in which virulence genes were detected were also antibiotic-resistant. All the CNS isolates harboring virulence genes (n = 27, 57.4%) were antimicrobial-resistant. The prevalence of multidrug resistance was higher (59.6%) in CNS than in CPS (26.3%) isolates. Regarding the presence of antibiotic-resistance genes, blaZ (penicillin-resistant) was the most frequent in both CPS (42.1%) and CNS (87.2%), followed by the mecA (encoding methicillin resistance) and vancA genes (vancomycin-resistant), which represented 36.8% and 31.6% in CPS isolates and 46.8% in CNS isolates, respectively. The prevalence of vancomycin-resistant staphylococci has been increasing worldwide and, to our knowledge, this is the first study to report the occurrence of vancomycin-resistant staphylococci in Mozambique. These results emphasize the need to investigate CNS isolates in parallel with CPS, as both constitute public health hazards, given their potential to produce SE and spread antimicrobial resistance genes.